Regional Dynamics Model (REDYN) | Open Energy Information
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Static and Dynamic Modeling of a Solar Active Region. I: Soft X-Ray Emission
Harry P. Warren; Amy R. Winebarger
2006-09-01
Recent simulations of solar active regions have shown that it is possible to reproduce both the total intensity and the general morphology of the high temperature emission observed at soft X-ray wavelengths using static heating models. There is ample observational evidence, however, that the solar corona is highly variable, indicating a significant role for dynamical processes in coronal heating. Because they are computationally demanding, full hydrodynamic simulations of solar active regions have not been considered previously. In this paper we make first application of an impulsive heating model to the simulation of an entire active region, AR8156 observed on 1998 February 16. We model this region by coupling potential field extrapolations to full solutions of the time-dependent hydrodynamic loop equations. To make the problem more tractable we begin with a static heating model that reproduces the emission observed in 4 different \\textit{Yohkoh} Soft X-Ray Telescope (SXT) filters and consider dynamical heating scenarios that yield time-averaged SXT intensities that are consistent with the static case. We find that it is possible to reproduce the total observed soft X-ray emission in all of the SXT filters with a dynamical heating model, indicating that nanoflare heating is consistent with the observational properties of the high temperature solar corona.
Particle dynamics in a non-flaring solar active region model
Threlfall, J; Neukirch, T; Parnell, C E
2015-01-01
The aim of this work is to investigate and characterise particle behaviour in a (observationally-driven) 3D MHD model of the solar atmosphere above a slowly evolving, non-flaring active region. We use a relativistic guiding-centre particle code to investigate particle acceleration in a single snapshot of the 3D MHD simulation. Despite the lack of flare-like behaviour in the active region, direct acceleration of electrons and protons to non-thermal energies ($\\lesssim420$MeV) was found, yielding spectra with high-energy tails which conform to a power law. Examples of particle dynamics, including particle trapping caused by local electric rather than magnetic field effects, are observed and discussed, together with implications for future experiments which simulate non-flaring active region heating and reconnection.
Dynamical Coupled-Channel Model of Meson Production Reactions in the Nucleon Resonance Region
T.-S. H. Lee; A. Matsuyama; T. Sato
2006-11-15
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.
1992-01-01
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.
Forest dynamics at regional scales: predictive models constrained with inventory data
Lines, Emily
2012-06-12
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...
Penny, Will
Hierarchical Dynamic Models Will Penny OU Processes Embedding OU(2) process Dynamic Models Hierarchical Dynamic Models Will Penny 26th May 2011 #12;Hierarchical Dynamic Models Will Penny OU Processes Dynamic Models Will Penny OU Processes Embedding OU(2) process Dynamic Models Generalised coordinates
Modeling the Dynamics of Desakota Regions: Global - Local Nexus in the Taipei Metropolitan Area
Wu, Bing-Sheng
2010-10-12
in 1991, focuses on how internal domestic and local forces drive the specific rural-urban transformation in Asia. However, the McGee-Ginsburg model does not emphasize the importance of globalization on Asian urbanization. To fill the gap, this study...
Xue, Yongkang
Dynamic downscaling of 22-year CFS winter seasonal hindcasts with the UCLA-ETA regional climate for Environmental Prediction Climate Forecast System (NCEP CFS), winter season predictions over the contiguous in the study. CFS over-predicts the precipitation in eastern and western US by as much as 45 and 90
Modeling regional power transfers
Kavicky, J.A.; Veselka, T.D.
1994-03-01
The Spot Market Network (SMN) model was used to estimate spot market transactions and prices between various North American Electric Reliability Council (NERC) regions for summer on-peak situations. A preliminary analysis of new or proposed additions to the transmission network was performed. The effects of alternative exempt wholesale generator (EWG) options on spot market transactions and the transmission system are also studied. This paper presents the SMN regional modelling approach and summarizes simulation results. Although the paper focuses on a regional network representation, a discussion of how the SMN model was used to represent a detailed utility-level network is also presented.
[CII] dynamics in the S140 region
Dedes, C.; Röllig, M.; Okada, Y.; Ossenkopf, V.; Mookerjea, B.; Collaboration: WADI Team
2015-01-22
We report the observation of [C II] emission in a cut through the S140 region together with single pointing observations of several molecular tracers, including hydrides, in key regions of the photon-dominated region (PDR) and molecular cloud [1]. At a distance of 910 pc, a BOV star ionizes the edge of the molecular cloud L1204, creating S140. In addition, the dense molecular cloud hosts a cluster of embedded massive young stellar objects only 75' from the H II region [e.g. 2, 3]. We used HIFI on Herschel to observe [CII] in a strip following the direction of the impinging radiation across the ionisation front and through the cluster of embedded YSOs. With [C II], we can trace the ionising radiation and, together with the molecular tracers such as CO isotopologues and HCO{sup +}, study the dynamical processes in the region. Combining HIFIs high spectral resolution data with ground based molecular data allows us to study the dynamics and excitation conditions both in the ionization front and the dense molecular star forming region and model their physical conditions [4].
Smyth, Padhraic
2013-07-22
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
2004-12-01
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.
Palo, P.A.; Meggitt, D.J.; Nordell, W.J.
1983-05-01
This paper presents a summary of the development and validation of undersea cable dynamics computer models by the Naval Civil Engineering Laboratory (NCEL) under the sponsorship of the Naval Facilities Engineering Command. These models allow for the analysis of both small displacement (strumming) and large displacement (static and dynamic) deformations of arbitrarily configured cable structures. All of the large displacement models described in this paper are available to the public. This paper does not emphasize the theoretical development of the models (this information is available in other references) but emphasizes the various features of the models, the comparisons between model output and experimental data, and applications for which the models have been used.
High order hybrid discontinuous Galerkin regional ocean modelling
Ueckermann, Mattheus Percy
2014-01-01
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
2014-01-01
For this thesis, several tools for dynamic model development were developed and analyzed. Dynamic models can be used to simulate and optimize the behavior of a great number of natural and engineered systems, from the ...
Dynamic interactions between electricity prices and the regional economy
Bethapudi, Daniel Naveen
2005-08-29
In this thesis we study characterize the dynamic relationships among two electricity price variables (residential and commercial) and six regional economic variables in order to examine each individual variable??s role in regional economic activity...
Regional weather modeling on parallel computers.
Baillie, C.; Michalakes, J.; Skalin, R.; Mathematics and Computer Science; NOAA Forecast Systems Lab.; Norwegian Meteorological Inst.
1997-01-01
This special issue on 'regional weather models' complements the October 1995 special issue on 'climate and weather modeling', which focused on global models. In this introduction we review the similarities and differences between regional and global atmospheric models. Next, the structure of regional models is described and we consider how the basic algorithms applied in these models influence the parallelization strategy. Finally, we give a brief overview of the eight articles in this issue and discuss some remaining challenges in the area of adapting regional weather models to parallel computers.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Pau, G. S. H.; Bisht, G.; Riley, W. J.
2014-04-04
Existing land surface models (LSMs) describe physical and biological processes that occur over a wide range of spatial and temporal scales. For example, biogeochemical and hydrological processes responsible for carbon (CO2, CH4) exchanges with the atmosphere range from molecular scale (pore-scale O2 consumption) to tens of kilometer scale (vegetation distribution, river networks). Additionally, many processes within LSMs are nonlinearly coupled (e.g., methane production and soil moisture dynamics), and therefore simple linear upscaling techniques can result in large prediction error. In this paper we applied a particular reduced-order modeling (ROM) technique known as "Proper Orthogonal Decomposition mapping method" that reconstructs temporally-resolvedmore »fine-resolution solutions based on coarse-resolution solutions. We applied this technique to four study sites in a polygonal tundra landscape near Barrow, Alaska. Coupled surface-subsurface isothermal simulations were performed for summer months (June–September) at fine (0.25 m) and coarse (8 m) horizontal resolutions. We used simulation results from three summer seasons (1998–2000) to build ROMs of the 4-D soil moisture field for the four study sites individually (single-site) and aggregated (multi-site). The results indicate that the ROM produced a significant computational speedup (> 103) with very small relative approximation error (« less
Regions in Energy Market Models
Short, W.
2007-02-01
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.
Regions in Energy Market Models
2009-01-18
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.
Dynamic models for nonstationary signal segmentation
Penny, Will
Dynamic models for nonstationary signal segmentation William D. Penny and Stephen J. Roberts w.penny
DYNAMIC MODELING FUEL PROCESSORS
Mease, Kenneth D.
turbine module (compressor and turbine sub-modules) Catalytic oxidizer Combustor module Heat exchanger, PEM, Gas Turbine General Model Assumptions · 1D process flow · Well-stirred within nodal volume · Slow reactants #12;Steam Reformation Occurs in Reformer and Fuel Cells Methane reformation reaction Water Gas
Developing a Dynamic Pharmacophore Model for HIV-1 Integrase
Carlson, Heather A.; Masukawa, Keven M.; Rubins, Kathleen; Bushman, Frederic; Jorgensen, William L.; Lins, Roberto; Briggs, James; Mccammon, Andy
2000-05-11
We present the first receptor-based pharmacophore model for HIV-1 integrase. The development of ''dynamic'' pharmacophore models is a new method that accounts for the inherent flexibility of the active site and aims to reduce the entropic penalties associated with binding a ligand. Furthermore, this new drug discovery method overcomes the limitation of an incomplete crystal structure of the target protein. A molecular dynamics (MD) simulation describes the flexibility of the uncomplexed protein. Many conformational models of the protein are saved from the MD simulations and used in a series of multi-unit search for interacting conformers (MUSIC) simulations. MUSIC is a multiple-copy minimization method, available in the BOSS program; it is used to determine binding regions for probe molecules containing functional groups that complement the active site. All protein conformations from the MD are overlaid, and conserved binding regions for the probe molecules are identified. Those conserved binding regions define the dynamic pharmacophore model. Here, the dynamic model is compared to known inhibitors of the integrase as well as a three-point, ligand-based pharmacophore model from the literature. Also, a ''static'' pharmacophore model was determined in the standard fashion, using a single crystal structure. Inhibitors thought to bind in the active site of HIV-1 integrase fit the dynamic model but not the static model. Finally, we have identified a set of compounds from the Available Chemicals Directory that fit the dynamic pharmacophore model, and experimental testing of the compounds has confirmed several new inhibitors.
Modeling Blog Dynamics Michaela Gotz
Leskovec, Jure
Modeling Blog Dynamics Michaela G¨otz Cornell University goetz@cs.cornell.edu Jure Leskovec@cs.cmu.edu Christos Faloutsos Carnegie Mellon University christos@cs.cmu.edu Abstract How do blogs produce posts? What local, underlying mech- anisms lead to the bursty temporal behaviors observed in blog networks? Earlier
Coupling of Integrated Biosphere Simulator to Regional Climate Model Version 3
Winter, Jonathan (Jonathan Mark)
A description of the coupling of Integrated Biosphere Simulator (IBIS) to Regional Climate Model version 3 (RegCM3) is presented. IBIS introduces several key advantages to RegCM3, most notably vegetation dynamics, the ...
A Relativistic Dynamical Collapse Model
Philip Pearle
2014-12-21
A model is discussed where all operators are constructed from a quantum scalar field whose energy spectrum takes on all real values. The Schr\\"odinger picture wave function depends upon space and time coordinates for each particle, as well as an inexorably increasing evolution parameter $s$ which labels a foliation of space-like hypersurfaces. The model is constructed to be manifestly Lorentz invariant in the interaction picture. Free particle states and interactions are discussed in this framework. Then, the formalism of the CSL (Continuous Spontaneous Localization) theory of dynamical collapse is applied. The collapse-generating operator is chosen to to be the particle number space-time density. Unlike previous relativistically invariant models, the vacuum state is not excited. The collapse dynamics depends upon two parameters, a parameter $\\Lambda$ which represents the collapse rate/volume and a scale factor $\\ell$. A common example of collapse dynamics, involving a clump of matter in a superposition of two locations, is analyzed. The collapse rate is shown to be identical to that of non-relativistic CSL when the GRW-CSL choice of $\\ell=a=10^{-5}$cm, is made, along with $\\Lambda=\\lambda/a^{3}$ (GRW-CSL choice $\\lambda=10^{-16}s^{-1}$). However, it is also shown that the change of mass of a nucleon over the age of the universe is then unacceptably large. The case where $\\ell$ is the size of the universe is then considered. It is shown that the collapse behavior is satisfactory and the change of mass over the age of the universe is acceptably small, when $\\Lambda= \\lambda/\\ell a^{2}$.
Dynamical modeling of tidal streams
Bovy, Jo, E-mail: bovy@ias.edu [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)
2014-11-01
I present a new framework for modeling the dynamics of tidal streams. The framework consists of simple models for the initial action-angle distribution of tidal debris, which can be straightforwardly evolved forward in time. Taking advantage of the essentially one-dimensional nature of tidal streams, the transformation to position-velocity coordinates can be linearized and interpolated near a small number of points along the stream, thus allowing for efficient computations of a stream's properties in observable quantities. I illustrate how to calculate the stream's average location (its 'track') in different coordinate systems, how to quickly estimate the dispersion around its track, and how to draw mock stream data. As a generative model, this framework allows one to compute the full probability distribution function and marginalize over or condition it on certain phase-space dimensions as well as convolve it with observational uncertainties. This will be instrumental in proper data analysis of stream data. In addition to providing a computationally efficient practical tool for modeling the dynamics of tidal streams, the action-angle nature of the framework helps elucidate how the observed width of the stream relates to the velocity dispersion or mass of the progenitor, and how the progenitors of 'orphan' streams could be located. The practical usefulness of the proposed framework crucially depends on the ability to calculate action-angle variables for any orbit in any gravitational potential. A novel method for calculating actions, frequencies, and angles in any static potential using a single orbit integration is described in the Appendix.
Applying waste logistics modeling to regional planning
Holter, G.M.; Khawaja, A.; Shaver, S.R.; Peterson, K.L.
1995-05-01
Waste logistics modeling is a powerful analytical technique that can be used for effective planning of future solid waste storage, treatment, and disposal activities. Proper waste management is essential for preventing unacceptable environmental degradation from ongoing operations, and is also a critical part of any environmental remediation activity. Logistics modeling allows for analysis of alternate scenarios for future waste flowrates and routings, facility schedules, and processing or handling capacities. Such analyses provide an increased understanding of the critical needs for waste storage, treatment, transport, and disposal while there is still adequate lead time to plan accordingly. They also provide a basis for determining the sensitivity of these critical needs to the various system parameters. This paper discusses the application of waste logistics modeling concepts to regional planning. In addition to ongoing efforts to aid in planning for a large industrial complex, the Pacific Northwest Laboratory (PNL) is currently involved in implementing waste logistics modeling as part of the planning process for material recovery and recycling within a multi-city region in the western US.
Modelling and Dynamic Simulation for Process Control
Skogestad, Sigurd
principles for model development are outlined, and these principles are applied to a simple ash tank (which. In this paper we consider dynamic process models obtained using fundamental principles (eg. based reactor, a simple trend analysis using temperature measurements may be suĆcient. Dynamic models
Jamming transitions in force-based models for pedestrian dynamics
Chraibi, Mohcine; Tordeux, Antoine; Nishinari, Katsuhiro; Schadschneider, Andreas; Seyfried, Armin
2015-01-01
Force-based models describe pedestrian dynamics in analogy to classical mechanics by a system of second order ordinary differential equations. By investigating the linear stability of two main classes of forces, parameter regions with unstable homogeneous states are identified. In this unstable regime it is then checked whether phase transitions or stop-and-go waves occur. Results based on numerical simulations show, however, that the investigated models lead to unrealistic behavior in form of backwards moving pedestrians and overlapping. This is one reason why stop-and-go waves have not been observed in these models. The unrealistic behavior is not related to the numerical treatment of the dynamic equations but rather indicates an intrinsic problem of this model class. Identifying the underlying generic problems gives indications how to define models that do not show such unrealistic behavior. As an example we introduce a new force-based model which produces realistic jam dynamics without the appearance of u...
Quantitative Modeling of High Temperature Magnetization Dynamics
Zhang, Shufeng
2009-03-01
Final Technical Report Project title: Quantitative Modeling of High Temperature Magnetization Dynamics DOE/Office of Science Program Manager Contact: Dr. James Davenport
Conceptual aircraft dynamics from inverse aircraft modeling
Ziegler, Gregory E
1999-01-01
This thesis presents a method of construe' ting a nonlinear dynamics model of a theoretical aircraft from the nonlinear batch simulation of an existing aircrew This method provides control law designers with a method of fabricating nonlinear models...
Modeling-Computer Simulations At Nw Basin & Range Region (Pritchett...
Modeling-Computer Simulations At Nw Basin & Range Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer...
Modeling-Computer Simulations At Nw Basin & Range Region (Biasi...
Modeling-Computer Simulations At Nw Basin & Range Region (Biasi, Et Al., 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer...
Dynamics Modelling of Biolistic Gene Guns
Zhang, M.; Tao, W.; Pianetta, P.A.
2009-06-04
The gene transfer process using biolistic gene guns is a highly dynamic process. To achieve good performance, the process needs to be well understood and controlled. Unfortunately, no dynamic model is available in the open literature for analysing and controlling the process. This paper proposes such a model. Relationships of the penetration depth with the helium pressure, the penetration depth with the acceleration distance, and the penetration depth with the micro-carrier radius are presented. Simulations have also been conducted. The results agree well with experimental results in the open literature. The contribution of this paper includes a dynamic model for improving and manipulating performance of the biolistic gene gun.
Diamond Lattice Model of Semicrystalline Polyethylene in the Amorphous Region
Diamond Lattice Model of Semicrystalline Polyethylene in the Amorphous Region ZhongHui 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
The Central Region in M100: Observations and Modeling
J. H. Knapen; J. E. Beckman; C. H. Heller; I. Shlosman; R. S. de Jong
1995-06-19
We present new high-resolution observations of the center of the late-type spiral M100 (NGC 4321) supplemented by 3D numerical modeling of stellar and gas dynamics, including star formation (SF). NIR imaging has revealed a stellar bar, previously inferred from optical and 21 cm observations, and an ovally-shaped ring-like structure in the plane of the disk. The K isophotes become progressively elongated and skewed to the position angle of the bar (outside and inside the `ring') forming an inner bar-like region. The galaxy exhibits a circumnuclear starburst in the inner part of the K `ring'. Two maxima of the K emission have been observed to lie symmetrically with respect to the nucleus and equidistant from it slightly leading the stellar bar. We interpret the twists in the K isophotes as being indicative of the presence of a double inner Lindblad resonance (ILR) and test this hypothesis by modeling the gas flow in a self-consistent gas + stars disk embedded in a halo, with an overall NGC4321-like mass distribution. We have reproduced the basic morphology of the region (the bar, the large scale trailing shocks, two symmetric K peaks corresponding to gas compression maxima which lie at the caustic formed by the interaction of a pair of trailing and leading shocks in the vicinity of the inner ILR, both peaks being sites of SF, and two additional zones of SF corresponding to the gas compression maxima, referred usually as `twin peaks').
A Framework for Modeling Uncertainty in Regional Climate Change
climate models). The modeling framework revolves around the Massachusetts Institute of Technology (MITA Framework for Modeling Uncertainty in Regional Climate Change Erwan Monier, Xiang Gao, Jeffery processes of policy development and implementation, climate change research needs to focus on improving
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 Satellite Program-F13 (DMSP-F13). The generation of the Region 2 currents is associated with the direction
Regional Short-Term Energy Model (RSTEM) Overview
Reports and Publications (EIA)
2009-01-01
The Regional Short-Term Energy Model (RSTEM) utilizes estimated econometric relationships for demand, inventories and prices to forecast energy market outcomes across key sectors and selected regions throughout the United States.
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
2008-10-15
Gasification (or partial oxidation) is a vital component of 'clean coal' technology. Sulfur and nitrogen emissions can be reduced, overall energy efficiency is increased, and carbon dioxide recovery and sequestration are facilitated. Gasification units in an electric power generation plant produce a fuel for driving combustion turbines. Gasification units in a chemical plant generate gas, which can be used to produce a wide spectrum of chemical products. Future plants are predicted to be hybrid power/chemical plants with gasification as the key unit operation. The widely used process simulator Aspen Plus provides a library of models that can be used to develop an overall gasifier model that handles solids. So steady-state design and optimization studies of processes with gasifiers can be undertaken. This paper presents a simple approximate method for achieving the objective of having a gasifier model that can be exported into Aspen Dynamics. The basic idea is to use a high molecular weight hydrocarbon that is present in the Aspen library as a pseudofuel. This component should have the same 1:1 hydrogen-to-carbon ratio that is found in coal and biomass. For many plantwide dynamic studies, a rigorous high-fidelity dynamic model of the gasifier is not needed because its dynamics are very fast and the gasifier gas volume is a relatively small fraction of the total volume of the entire plant. The proposed approximate model captures the essential macroscale thermal, flow, composition, and pressure dynamics. This paper does not attempt to optimize the design or control of gasifiers but merely presents an idea of how to dynamically simulate coal gasification in an approximate way.
Modeling of Alpine Atmospheric Dynamics II
Gohm, Alexander
Modeling of Alpine Atmospheric Dynamics II 707.424, VU 2, SS2005 Unit 7: Model code structure: mesoscale convective system 17-18 April 2004: Sierra hydraulic jump case 21 January 2005: the "Universiade) Introduction (brief description of the phenomenon and a description of the model and of the measurements
Dynamic modeling issues for power system applications
Song, Xuefeng
2005-02-17
Power system dynamics are commonly modeled by parameter dependent nonlinear differential-algebraic equations (DAE) x ???p y x f ) and 0 = p y x g ) . Due to (,, (,, the algebraic constraints, we cannot directly perform...
Ocean dynamics and thermodynamics in the tropical Indo- Pacific region
Drushka, Kyla
2011-01-01
an effective tsunami warning system for this region.to put an effective tsunami warning system in place. The
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) ...
Protein viscoelastic dynamics: a model system
Craig Fogle; Joseph Rudnick; David Jasnow
2015-02-02
A model system inspired by recent experiments on the dynamics of a folded protein under the influence of a sinusoidal force is investigated and found to replicate many of the response characteristics of such a system. The essence of the model is a strongly over-damped oscillator described by a harmonic restoring force for small displacements that reversibly yields to stress under sufficiently large displacement. This simple dynamical system also reveals unexpectedly rich behavior, exhibiting a series of dynamical transitions and analogies with equilibrium thermodynamic phase transitions. The effects of noise and of inertia are briefly considered and described.
Consistent nonlinear dynamics: identifying model inadequacy
Patrick E. McSharry; Leonard A. Smith
2004-03-09
Empirical modelling often aims for the simplest model consistent with the data. A new technique is presented which quantifies the consistency of the model dynamics as a function of location in state space. As is well-known, traditional statistics of nonlinear models like root-mean-square (RMS) forecast error can prove misleading. Testing consistency is shown to overcome some of the deficiencies of RMS error, both within the perfect model scenario and when applied to data from several physical systems using previously published models. In particular, testing for consistent nonlinear dynamics provides insight towards (i) identifying when a delay reconstruction fails to be an embedding, (ii) allowing state dependent model selection and (iii) optimising local neighbourhood size. It also provides a more relevant (state dependent) threshold for identifying false nearest neighbours.
Bayesian Nonparametric Inference of Switching Dynamic Linear Models
Fox, Emily Beth
Many complex dynamical phenomena can be effectively modeled by a system that switches among a set of conditionally linear dynamical modes. We consider two such models: the switching linear dynamical system (SLDS) and the ...
Modeling the Dynamics of Fermentation and Respiratory
Sheffield, University of
Modeling the Dynamics of Fermentation and Respiratory Processes in a Groundwater Plume of Phenolic implemented into a field- scale reactive transport model of a groundwater plume of phenolic contaminants toxicity toward degradation, bioavailability of mineral oxides, and adsorption of biogenic Fe(II) species
Akimkin, V V; Pavlyuchenkov, Ya N; Wiebe, D S
2015-01-01
We consider dust drift under the influence of stellar radiation pressure during the pressure-driven expansion of an HII region using the chemo-dynamical model MARION. Dust size distribution is represented by four dust types: conventional polycyclic aromatic hydrocarbons (PAHs), very small grains (VSGs), big grains (BGs) and also intermediate-sized grains (ISGs), which are larger than VSGs and smaller than BGs. The dust is assumed to move at terminal velocity determined locally from the balance between the radiation pressure and gas drag. As Coulomb drag is an important contribution to the overall gas drag, we evaluate a grain charge evolution within the HII region for each dust type. BGs are effectively swept out of the HII region. The spatial distribution of ISGs within the HII region has a double peak structure, with a smaller inner peak and a higher outer peak. PAHs and VSGs are mostly coupled to the gas. The mean charge of PAHs is close to zero, so they can become neutral from time to time because of char...
Six Degree of Freedom Morphing Aircraft Dynamical Model with Aerodynamics
Niksch, Adam
2010-01-14
model of a morphing aircraft is needed. This paper develops an aerodynamic model and a dynamic model of a morphing flying wing aircraft. The dynamic model includes realistic aerodynamic forces, consisting of lift, drag, and pitching moment about...
The internal dynamical equilibrium of HII regions: a statistical study
M. Relano; J. E. Beckman; A. Zurita; M. Rozas; C. Giammanco
2004-10-20
We present an analysis of the integrated Halpha emission line profiles for the HII region population of the spiral galaxies NGC 1530, NGC 6951 and NGC 3359. We show that 70% of the line profiles show two or three Gaussian components. The relations between the Halpha luminosity and non-thermal line width for the HII regions of the three galaxies are studied and compared with the relation found taken all the HII regions of the three galaxies as a single distribution. A clearer envelope in non-thermal line width is found when only those HII regions with non-thermal line width bigger than 13kms are considered. The linear fit for the envelope is logL=36.8+2.0*log(sigma). The masses of the HII regions on the envelope using the virial theorem and the mass estimates from the Halpha luminosity are comparable, which offers evidence that the HII regions on the envelope are virialized systems, while the remaining regions, the majority, are not in virial equilibrium.
Analytical modeling of balloon launch dynamics
Strganac, Thomas W
1980-01-01
aerodynam1cs. Actual fl1ght data has been used to qualify the model via comparisons of the launch trans1ent configurations. DEDICATION To my father. . THOMAS JOHN STRGANAC 1922-1980 . . . who provided me the examp1e to fo1Iow in life. ACKNOWLEDGEMENTS... OF TABLES. LIST OF FIGURES NOMENCLATURE. INTRODUCTION. PRESENT STATUS. DYNAMIC MODEL Forces on the Balloon. Buoyancy . Weight Distribution. Catenary . Bubble Aerodynamics, Equations of Motion. Kutta-Simpson Solution Technique NUMERICAL MODEL...
F region above kauai: Measurement, model, modification
Johnson, C.Y.; Sjolander, G.W.; Oran, E.S.; Young, T.R.; Bernhardt, P.A.; Da Rosa, A.V.
1980-08-01
A detailed description and analysis is presented of the Lagopedo II results. The rocket was launched on September 11, 1977. Prior to an explosive chemical release a rocket-borne ion mass spectrometer and dual-frequency beacon measured the ion composition and electron content of the undisturbed F region above Kauai, Hawaii. These results are compared to a detailed calculation of ionospheric ion denities. Considerable H/sub 2/O outgassing produced measurable 18/sup +/(H/sub 2/O/sup +/) and 19/sup +/(H/sub 3/O/sup +/) currents which together with O/sup +/ current were used to determine the H/sup 3/O/sup +//H/sub 2/O/sup +/ dissociative recombination rate ratio. The explosive event at 283 km swept clean a l-km-radius region. The boundary of the ionic void was characterized by a steep gradient in the ion density. Results for the first 60 s after the event are presented which show changes in ambient ion species 14/sup +/, 16/sup +/, 30/sup +/, new reactant species 15/sup +/, 17/sup +/, 18/sup +/, 19/sup +/, 27/sup +/, and 46/sup +/, and evidence of ionic depletion by sweeping.
Dynamic Precursors of Flares in Active Region NOAA 10486
Korsos, M B; Baranyi, T; Ludmany, A
2015-01-01
Four different methods are applied here to study the precursors of flare activity in the Active Region NOAA 10486. Two approaches track the temporal behaviour of suitably chosen features (one, the weighted horizontal gradient WGM, is generalised form the horizontal gradient of the magnetic field, GM; another is the sum of the horizontal gradient of the magnetic field, GS, for all sunspot pairs). WGM is a photospheric indicator that is a proxy measure of magnetic non-potentiality of a specific area of the active region, i.e. it captures the temporal variation of the weighted horizontal gradient of magnetic flux summed up for the region where opposite magnetic polarities are highly mixed. The third one, referred to as the separateness parameter, S(lf), considers the overall morphology. Further, GS and S(lf) are photospheric newly defined quick-look indicators of the polarity mix of the entire active region. The fourth method is tracking the temporal variation of small x-ray flares, their times of succession and...
The role of stellar feedback in the dynamics of H II regions
Lopez, Laura A.; Castro, Daniel [MIT-Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, 37-664H, Cambridge, MA 02139 (United States); Krumholz, Mark R.; Prochaska, J. Xavier; Ramirez-Ruiz, Enrico [Department of Astronomy and Astrophysics, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95060 (United States); Bolatto, Alberto D., E-mail: lopez@space.mit.edu [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
2014-11-10
Stellar feedback is often cited as the biggest uncertainty in galaxy formation models today. This uncertainty stems from a dearth of observational constraints as well as the great dynamic range between the small scales (?1 pc) where the feedback originates and the large scales of galaxies (?1 kpc) that are shaped by this feedback. To bridge this divide, in this paper we aim to assess observationally the role of stellar feedback at the intermediate scales of H II regions (?10-100 pc). In particular, we employ multiwavelength data to examine several stellar feedback mechanisms in a sample of 32 H II regions (with ages ?3-10 Myr) in the Large and Small Magellanic Clouds, respectively. Using optical, infrared, radio, and X-ray images, we measure the pressures exerted on the shells from the direct stellar radiation, the dust-processed radiation, the warm ionized gas, and the hot X-ray-emitting gas. We find that the warm ionized gas dominates over the other terms in all of the sources, although two have comparable dust-processed radiation pressures to their warm gas pressures. The hot gas pressures are comparatively weak, while the direct radiation pressures are one to two orders of magnitude below the other terms. We discuss the implications of these results, particularly highlighting evidence for hot gas leakage from the H II shells and regarding the momentum deposition from the dust-processed radiation to the warm gas. Furthermore, we emphasize that similar observational work should be done on very young H II regions to test whether direct radiation pressure and hot gas can drive the dynamics at early times.
Modeling of Reactor Kinetics and Dynamics
Matthew Johnson; Scott Lucas; Pavel Tsvetkov
2010-09-01
In order to model a full fuel cycle in a nuclear reactor, it is necessary to simulate the short time-scale kinetic behavior of the reactor as well as the long time-scale dynamics that occur with fuel burnup. The former is modeled using the point kinetics equations, while the latter is modeled by coupling fuel burnup equations with the kinetics equations. When the equations are solved simultaneously with a nonlinear equation solver, the end result is a code with the unique capability of modeling transients at any time during a fuel cycle.
DYNAMIC MODELING PROTON EXCHANGE MEMBRANE FUEL CELL
Mease, Kenneth D.
DYNAMIC MODELING PROTON EXCHANGE MEMBRANE FUEL CELL OVERVIEW Current/Completed Plug Power to garner SCAQMD funding for fuel cell testing GenCore system is sensitive to diluents · As built design stream to compensate for removal of EGR · Functionality of the modified GenCore Fuel Cell system
Keratin Dynamics: Modeling the Interplay between Turnover and Transport
Stephanie Portet; Anotida Madzvamuse; Andy Chung; Rudolf E. Leube; Reinhard Windoffer
2015-04-01
Keratin are among the most abundant proteins in epithelial cells. Functions of the keratin network in cells are shaped by their dynamical organization. Using a collection of experimentally-driven mathematical models, different hypotheses for the turnover and transport of the keratin material in epithelial cells are tested. The interplay between turnover and transport and their effects on the keratin organization in cells are hence investigated by combining mathematical modeling and experimental data. Amongst the collection of mathematical models considered, a best model strongly supported by experimental data is identified. Fundamental to this approach is the fact that optimal parameter values associated with the best fit for each model are established. The best candidate among the best fits is characterized by the disassembly of the assembled keratin material in the perinuclear region and an active transport of the assembled keratin. Our study shows that an active transport of the assembled keratin is required to explain the experimentally observed keratin organization.
Blount, G.; Greeley, R.; Christensen, P.R. (Arizona State Univ., Tempe (USA)); Smith, M.O.; Adams, J.B. (Univ. of Washington, Seattle (USA))
1990-09-10
Spatial variations in sand composition were mapped on a regional scale in a terrestrial sand sea, the Gran Desierto of Sonora, Mexico. Mesoscale mapping on a satellite image base allowed quantitative interpretation of the dynamic development of sand sheets and dunes. The results were used to interpret the Quaternary geologic history of the tectonically active region at the mouth of the Colorado River. Landsat thematic mapper multispectral images were used to predict the abundance of different mineralogies of sand grains in a mixed aeolian terrain. A spectral mixing model separated the effects of vegetation and topographically induced shading and shadow from the effects produced by different mineral and rock types. Compositions determined remotely agreed well with samples from selected areas within the spectral limitations of the thematic mapper. A simple discrimination capability for active versus inactive sand surfaces is demonstrated based upon differences in the percentage of low-albedo accessory grains occurring on dormant aeolian surfaces. A technique for discriminating between low-albedo materials and macroscopic shade is implemented by combing thermal images with the results of the spectral mixing model. The image analysis revealed important compositional variations over large areas that were not readily apparent in the field.
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
2010-11-08
This study focuses on defining and comparing response features that can be used for structural dynamics model validation studies. Features extracted from dynamic responses obtained analytically or experimentally, such as basic signal statistics, frequency spectra, and estimated time-series models, can be used to compare characteristics of structural system dynamics. By comparing those response features extracted from experimental data and numerical outputs, validation and uncertainty quantification of numerical model containing uncertain parameters can be realized. In this study, the applicability of some response features to model validation is first discussed using measured data from a simple test-bed structure and the associated numerical simulations of these experiments. issues that must be considered were sensitivity, dimensionality, type of response, and presence or absence of measurement noise in the response. Furthermore, we illustrate a comparison method of multivariate feature vectors for statistical model validation. Results show that the outlier detection technique using the Mahalanobis distance metric can be used as an effective and quantifiable technique for selecting appropriate model parameters. However, in this process, one must not only consider the sensitivity of the features being used, but also correlation of the parameters being compared.
Switched Dynamical Latent Force Models for Modelling Transcriptional Regulation
López-Lopera, Andrés F
2015-01-01
In order to develop statistical approaches for transcription networks, statistical community has proposed several methods to infer activity levels of proteins, from time-series measurements of targets' expression levels. A few number of approaches have been proposed in order to outperform the representation of fast switching time instants, but computational overheads are significant due to complex inference algorithms. Using the theory related to latent force models (LFM), the development of this project provide a switched dynamical hybrid model based on Gaussian processes (GPs). To deal with discontinuities in dynamical systems (or latent driving force), an extension of the single input motif approach is introduced, that switches between different protein concentrations, and different dynamical systems. This creates a versatile representation for transcription networks that can capture discrete changes and non-linearities in the dynamics. The proposed method is evaluated on both simulated data and real data,...
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 ...
Transactions in GIS Dynamic Modelling and Visualization on the Internet
Worboys, Mike
1 Transactions in GIS Dynamic Modelling and Visualization on the Internet Bo Huang* and Michael F for GIS to incorporate dynamic analytic models. At the same time, there is a need to distribute results of dynamic GIS using the Internet. Therefore, this paper sets out to explore the implementation of dynamic
Stochastic Lagrangian dynamics for charged flows in the E-F regions of ionosphere
Tang Wenbo; Mahalov, Alex [School of Mathematical and Statistical Sciences, Arizona State University, Tempe, Arizona 85287 (United States)
2013-03-15
We develop a three-dimensional numerical model for the E-F region ionosphere and study the Lagrangian dynamics for plasma flows in this region. Our interest rests on the charge-neutral interactions and the statistics associated with stochastic Lagrangian motion. In particular, we examine the organizing mixing patterns for plasma flows due to polarized gravity wave excitations in the neutral field, using Lagrangian coherent structures (LCS). LCS objectively depict the flow topology-the extracted attractors indicate generation of ionospheric density gradients, due to accumulation of plasma. Using Lagrangian measures such as the finite-time Lyapunov exponents, we locate the Lagrangian skeletons for mixing in plasma, hence where charged fronts are expected to appear. With polarized neutral wind, we find that the corresponding plasma velocity is also polarized. Moreover, the polarized velocity alone, coupled with stochastic Lagrangian motion, may give rise to polarized density fronts in plasma. Statistics of these trajectories indicate high level of non-Gaussianity. This includes clear signatures of variance, skewness, and kurtosis of displacements taking polarized structures aligned with the gravity waves, and being anisotropic.
A Dynamic Network Oligopoly Model Transportation Costs, Product Differentiation,
Nagurney, Anna
of Operations & Information Management Isenberg School of Management University of Massachusetts AmherstA Dynamic Network Oligopoly Model with Transportation Costs, Product Differentiation, and Quality of Massachusetts Amherst A Dynamic Network Oligopoly Model with Quality Competition #12;Acknowledgments
Modeling Dynamics of Post Disaster Recovery
Nejat, Ali
2012-10-19
: Civil Engineering MODELING DYNAMICS OF POST DISASTER RECOVERY A Dissertation by ALI NEJAT Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR... OF PHILOSOPHY Approved by: Chair of Committee, Ivan Damnjanovic Committee Members, Stuart D. Anderson Kenneth F. Reinschmidt Sergiy Butenko Arnold Vedlitz Head of Department, John Niedzwecki August 2011 Major Subject: Civil Engineering...
A Spatial Analysis of Multivariate Output from Regional Climate Models
Sain, Steve
, Columbus, OH 43210, ncressie@stat.osu.edu. 1 #12;1 Introduction Many processes in the Earth system cannot, etc. Climate models attempt to represent this system, as well as to incorporate anthropogenic forcingsA Spatial Analysis of Multivariate Output from Regional Climate Models Stephan R. Sain,1 Reinhard
DYNAMICAL MODELING OF GALAXY MERGERS USING IDENTIKIT
Privon, G. C.; Evans, A. S.; Barnes, J. E.; Hibbard, J. E.; Yun, M. S.; Mazzarella, J. M.; Armus, L.; Surace, J.
2013-07-10
We present dynamical models of four interacting systems: NGC 5257/8, The Mice, the Antennae, and NGC 2623. The parameter space of the encounters are constrained using the Identikit model-matching and visualization tool. Identikit utilizes hybrid N-body and test particle simulations to enable rapid exploration of the parameter space of galaxy mergers. The Identikit-derived matches of these systems are reproduced with self-consistent collisionless simulations which show very similar results. The models generally reproduce the observed morphology and H I kinematics of the tidal tails in these systems with reasonable properties inferred for the progenitor galaxies. The models presented here are the first to appear in the literature for NGC 5257/8 and NGC 2623, and The Mice and the Antennae are compared with previously published models. Based on the assumed mass model and our derived initial conditions, the models indicate that the four systems are currently being viewed 175-260 Myr after first passage and cover a wide range of merger stages. In some instances there are mismatches between the models and the data (e.g., in the length of a tail); these are likely due to our adoption of a single mass model for all galaxies. Despite the use of a single mass model, these results demonstrate the utility of Identikit in constraining the parameter space for galaxy mergers when applied to real data.
Sensitivity Analysis of a Dynamic Fleet Management Model Using Approximate Dynamic Programming
Topaloglu, Huseyin
of fleet management models is to make the vehicle repositioning and vehicle-to-load assignment decisions soSensitivity Analysis of a Dynamic Fleet Management Model Using Approximate Dynamic Programming present tractable algorithms to assess the sensitivity of a stochastic dynamic fleet management model
Introducing a new 3D dynamical model for barred galaxies
Jung, Christof
2015-01-01
The regular or chaotic dynamics of an analytical realistic three dimensional model composed of a spherically symmetric central nucleus, a bar and a flat disk is investigated. For describing the properties of the bar we introduce a new simple dynamical model and we explore the influence on the character of orbits of all the involved parameters of it, such as the mass and the scale length of the bar, the major semi-axis and the angular velocity of the bar as well as the energy. Regions of phase space with ordered and chaotic motion are identified in dependence on these parameters and for breaking the rotational symmetry. First we study in detail the dynamics in the invariant plane $z = p_z = 0$ using the Poincar\\'e map as a basic tool and then we study the full 3 dimensional case using the SALI method as principal tool for distinguishing between order and chaos. We also present strong evidence obtained through the numerical simulations that our new bar model can realistically describe the formation and the evol...
Restoration of the Potosi Dynamic Model 2010
Adushita, Yasmin; Leetaru, Hannes
2014-09-30
In topical Report DOE/FE0002068-1 [2] technical performance evaluations on the Cambrian Potosi Formation were performed through reservoir modeling. The data included formation tops from mud logs, well logs from the VW1 and the CCS1 wells, structural and stratigraphic formation from three dimensional (3D) seismic data, and field data from several waste water injection wells for Potosi Formation. Intention was for two million tons per annum (MTPA) of CO2 to be injected for 20 years. In this Task the 2010 Potosi heterogeneous model (referred to as the "Potosi Dynamic Model 2010" in this report) was re-run using a new injection scenario; 3.2 MTPA for 30 years. The extent of the Potosi Dynamic Model 2010, however, appeared too small for the new injection target. It was not sufficiently large enough to accommodate the evolution of the plume. Also, it might have overestimated the injection capacity by enhancing too much the pressure relief due to the relatively close proximity between the injector and the infinite acting boundaries. The new model, Potosi Dynamic Model 2013a, was built by extending the Potosi Dynamic Model 2010 grid to 30 miles x 30 miles (48 km by 48 km), while preserving all property modeling workflows and layering. This model was retained as the base case. Potosi Dynamic Model 2013.a gives an average CO2 injection rate of 1.4 MTPA and cumulative injection of 43 Mt in 30 years, which corresponds to 45% of the injection target. This implies that according to this preliminary model, a minimum of three (3) wells could be required to achieve the injection target. The injectivity evaluation of the Potosi formation will be revisited in topical Report 15 during which more data will be integrated in the modeling exercise. A vertical flow performance evaluation could be considered for the succeeding task to determine the appropriate tubing size, the required injection tubing head pressure (THP) and to investigate whether the corresponding well injection rate falls within the tubing erosional velocity limit. After 30 years, the plume extends 15 miles (24 km) in E-W and 14 miles (22 km) in N-S directions. After injection is completed, the plume continues to migrate laterally, mainly driven by the remaining pressure gradient. After 100 years post-injection, the plume extends 17 miles (27 km) in E-W and 15 miles (24 km) in N-S directions. The increase of reservoir pressure at the end of injection is approximately 370 psia around the injector and gradually decreases away from the well. The reservoir pressure increase is less than 30 psia beyond 14 miles (22 km) away from injector. The initial reservoir pressure is restored after approximately 20 years post-injection. This result, however, is associated with uncertainties on the boundary conditions, and a sensitivity analysis could be considered for the succeeding tasks. It is important to remember that the respective plume extent and areal pressure increase corresponds to an injection of 43 Mt CO2. Should the targeted cumulative injection of 96 Mt be achieved; a much larger plume extent and areal pressure increase could be expected. Re-evaluating the permeability modeling, vugs and heterogeneity distributions, and relative permeability input could be considered for the succeeding Potosi formation evaluations. A simulation using several injectors could also be considered to determine the required number of wells to achieve the injection target while taking into account the pressure interference.
AFDM: An Advanced Fluid-Dynamics Model
Bohl, W.R.; Parker, F.R. (Los Alamos National Lab., NM (USA)); Wilhelm, D. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Neutronenphysik und Reaktortechnik); Berthier, J. (CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France)); Goutagny, L. (CEA Centre d'Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (France). Inst. de Protection et de Surete Nucleaire); Ninokata,
1990-09-01
AFDM, or the Advanced Fluid-Dynamics Model, is a computer code that investigates new approaches simulating the multiphase-flow fluid-dynamics aspects of severe accidents in fast reactors. The AFDM formalism starts with differential equations similar to those in the SIMMER-II code. These equations are modified to treat three velocity fields and supplemented with a variety of new models. The AFDM code has 12 topologies describing what material contacts are possible depending on the presence or absence of a given material in a computational cell, on the dominant liquid, and on the continuous phase. Single-phase, bubbly, churn-turbulent, cellular, and dispersed flow regimes are permitted for the pool situations modeled. Virtual mass terms are included for vapor in liquid-continuous flow. Interfacial areas between the continuous and discontinuous phases are convected to allow some tracking of phenomenological histories. Interfacial areas are also modified by models of nucleation, dynamic forces, turbulence, flashing, coalescence, and mass transfer. Heat transfer is generally treated using engineering correlations. Liquid-vapor phase transitions are handled with the nonequilibrium, heat-transfer-limited model, whereas melting and freezing processes are based on equilibrium considerations. Convection is treated using a fractional-step method of time integration, including a semi-implicit pressure iteration. A higher-order differencing option is provided to control numerical diffusion. The Los Alamos SESAME equation-of-state has been implemented using densities and temperatures as the independent variables. AFDM programming has vectorized all computational loops consistent with the objective of producing an exportable code. 24 refs., 4 figs.
A Game-Theoretical Dynamic Model for Electricity Markets
Oct 6, 2010 ... Abstract: We present a game-theoretical dynamic model for competitive electricity markets.We demonstrate that the model can be used to ...
Short-Term Energy Outlook Model Documentation: Regional Residential Heating Oil Price Model
Reports and Publications (EIA)
2009-01-01
The regional residential heating oil price module of the Short-Term Energy Outlook (STEO) model is designed to provide residential retail price forecasts for the 4 census regions: Northeast, South, Midwest, and West.
Short-Term Energy Outlook Model Documentation: Regional Residential Propane Price Model
Reports and Publications (EIA)
2009-01-01
The regional residential propane price module of the Short-Term Energy Outlook (STEO) model is designed to provide residential retail price forecasts for the 4 Census regions: Northeast, South, Midwest, and West.
Design of a next-generation regional weather research and forecast model.
Michalakes, J.
1999-01-13
The Weather Research and Forecast (WRF) model is a new model development effort undertaken jointly by the National Center for Atmospheric Research (NCAR), the National Oceanic and Atmospheric Administration (NOAA), and a number of collaborating institutions and university scientists. The model is intended for use by operational NWP and university research communities, providing a common framework for idealized dynamical studies, fill physics numerical weather prediction, air-quality simulation, and regional climate. It will eventually supersede large, well-established but aging regional models now maintained by the participating institutions. The WRF effort includes re-engineering the underlying software architecture to produce a modular, flexible code designed from the outset to provide portable performance across diverse computing architectures. This paper outlines key elements of the WRF software design.
Dislocation dynamics: from microscopic models to macroscopic crystal plasticity
Hajj, A El; Monneau, R
2009-01-01
In this paper we study the connection between four models describing dislocation dynamics: a generalized 2D Frenkel-Kontorova model at the atomic level, the Peierls-Nabarro model, the discrete dislocation dynamics and a macroscopic model with dislocation densities. We show how each model can be deduced from the previous one at a smaller scale.
Dynamical model for light composite fermions
Derman, E.
1981-04-01
A simple dynamical model for the internal structure of the three light lepton and quark generations (..nu../sub e/,e,u,d), (..nu../sub ..mu../,..mu..,c,s), and (..nu../sub tau/,tau,t,b) is proposed. Each generation is constructed of only one fundamental massive generation F=(L-italic/sup 0/,L/sup -/,U,D) with the same (SU/sub 3/)/sub c/ x SU/sub 2/ x U/sub 1/ quantum numbers as the light generations, bound to a core of one or more massive Higgs bosons H, where H is the single physical Higgs boson necessary for spontaneous symmetry breaking in the standard model. For example, e/sup -/=L/sup -/H), ..mu../sup -/=L/sup -/HH), tau/sup -/=L/sup -/HHH). It is shown that the known binding force due to H exchange is attractive and strong enough to produce light bound states. Dynamical calculations for the bound-state composite fermions using the Bethe-Salpeter equation, together with some phenomenological imput, suggest M/sub H/approx.16 TeV and M/sub F/approx.100 GeV. It is likely that such bound states can have properties compatible with the up to now apparently elementary appearance of known fermions, for example, their Dirac magnetic moments and absence of intergeneration radiative decays (such as ..mu -->..e..gamma..). Phenomenological consequences and tests of the model are discussed.
Approach to Equilibrium of Glauber Dynamics In the One Phase Region. I: The Attractive Case
.g temperature and magnetic field) which do not give rise to a phase transition , must have a rapid (typically close to the line of first order phase transition was proved few years ago by the authors of the presentApproach to Equilibrium of Glauber Dynamics In the One Phase Region. I: The Attractive Case F
Observations of high-frequency internal waves in the Coastal Ocean Dynamics Region
Pringle, James "Jamie"
1 Observations of high-frequency internal waves in the Coastal Ocean Dynamics Region James M. Introduction In the deep ocean, away from horizontal and vertical boundaries, the high-frequency internal wave to examine how the high-frequency internal wave spectrum changes across a continental shelf. This is done
A nonlinear dynamic model of a once-through, helical-coil steam generator
Abdalla, M.A. [Oak Ridge Inst. for Science and Education, TN (United States)
1993-07-01
A dynamic model of a once-through, helical-coil steam generator is presented. The model simulates the advanced liquid metal reactor superheated cycle steam generator with a four-region, moving-boundary, drift-flux model. The model is described by a set of nonlinear differential equations derived from the fundamental equations of conversation of mass, energy, and momentum. Sample results of steady-state and transient calculations are presented.
Nonlinear Hybrid Dynamical Systems: Modeling, Optimal Control, and Applications
Stryk, Oskar von
Nonlinear Hybrid Dynamical Systems: Modeling, Optimal Control, and Applications Martin Buss1¨unchen, Germany Abstract. Nonlinear hybrid dynamical systems are the main focus of this paper. A modeling Introduction The recent interest in nonlinear hybrid dynamical systems has forced the merger of two very
Dynamical Systems Analysis of Various Dark Energy Models
Nandan Roy
2015-11-25
In this thesis, we used dynamical systems analysis to find the qualitative behaviour of some dark energy models. Specifically, dynamical systems analysis of quintessence scalar field models, chameleon scalar field models and holographic models of dark energy are discussed in this thesis.
Dynamical Systems Analysis of Various Dark Energy Models
Roy, Nandan
2015-01-01
In this thesis, we used dynamical systems analysis to find the qualitative behaviour of some dark energy models. Specifically, dynamical systems analysis of quintessence scalar field models, chameleon scalar field models and holographic models of dark energy are discussed in this thesis.
Adjoint modeling for atmospheric pollution process sensitivity at regional scale
Menut, Laurent
, a strong pollution event was documented over Paris as part of the Etude et Simulation de la Qualite´ de l'airAdjoint modeling for atmospheric pollution process sensitivity at regional scale Laurent Menut 1998 the pollution event changes from a well-marked ozone plume issued from Paris to a more general
Reference wind farm selection for regional wind power prediction models
Paris-Sud XI, Université 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
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 In this project we have performed spatial analysis of groundwater data in Thane and Latur districts of Maharashtra Groundwater Survey and Development Agency, Maharashtra), shape files for watershed boundaries and drainage
A regional modeling study of the entraining Mediterranean outflow
Ozgökmen, Tamay M.
A regional modeling study of the entraining Mediterranean outflow X. Xu,1,2 E. P. Chassignet,3 J. Fdependent entrainment parameterization of Xu et al. (2006). Given realistic topography and sufficient resolution of the outflow plume, and most importantly, the localized, strong entrainment that has been observed to occur
Linking Dynamical and Population Genetic Models of Persistent Viral Infection
Kelly, John K.; Williamson, Scott; Orive, Maria E.; Smith, Marilyn S.; Holt, Robert D.
2003-07-01
This article develops a theoretical framework to link dynamical and population genetic models of persistent viral infection. This linkage is useful because, while the dynamical and population genetic theories have developed ...
AFDM: An Advanced Fluid-Dynamics Model
Berthier, J. (CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France)); Wilhelm, D. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Neutronenphysik und Reaktortechnik); Bohl, W.R. (Los Alamos National Lab., NM (USA))
1990-09-01
This report consists of three parts. First, for the standard Advanced Fluid-Dynamics Model (AFDM), heat-transfer coefficients between components are worked out, depending on the different possible topologies. Conduction, convection, and radiative heat-transfer mechanisms are modeled. For solid particles, discontinuous phases that obey a rigid'' model, and components lacking relative motion, heat transfer is by conduction. Convection is represented for fluids in motion inside circulating'' bubbles and/or droplets. Radiation is considered between droplets in vapor continuous flow. In addition, a film-boiling model has been formulated, where radiation provides the lower limit on the fuel-to-coolant heat-transfer coefficient. Second, the momentum-exchange coefficients are defined for the standard AFDM. Between a continuous and discontinuous phase, the model consists of both laminar and turbulent terms. The most important feature is the drag coefficient in the turbulent term. It is calculated by a drag similarity hypothesis with limits for large Reynolds numbers, distorted particles,'' and churn-turbulent flow. A unique hysteresis algorithm exists to treat the liquid continuous to vapor continuous transition. Two discontinuous components are coupled using a turbulent term with an input drag coefficient. Fluid- structure momentum exchange is represented with a standard friction-factor correlation. Third, the formulas used for the AFDM simplified Step 1 models are discussed. These include the heat-transfer coefficients, the momentum-exchange functions, and the manner in which interfacial areas are determined from input length scales. The simplified modeling uses steady-state engineering correlations, as in SIMMER-II.
Regional-Scale Climate Change: Observations and Model Simulations
Raymond S. Bradley; Henry F. Diaz
2010-12-14
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.
Freezing and thawing a b s t r a c t Numerous cold regions water flow and energy transport models have. Simulated and/or observed climate change impacts in cryogenic soils include permafrost degradation, active that include the dynamic freezethaw process have been tested against analytical solutions, such as the Neumann
A Parallelizable and Approximate Dynamic Programming-Based Dynamic Fleet Management Model with
Topaloglu, Huseyin
-based dynamic fleet management model that can handle random load arrivals, random travel times and multiple-based model for the dynamic fleet management problem with random load arrivals, random travel times-based models for fleet management problems with random load arrivals, deterministic travel times and a single
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
Dynamics of a multigroup epidemiological model with group ...
Lamwah Chow
2011-09-22
spread across multiple countries and transmission between different subgroups in a ... Multigroup models have been used to study transmission dynamics of ...
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
2007-11-04
We use coordinated Hinode SOT/EIS observations that include high-resolution magnetograms, chromospheric and TR imaging and TR/coronal spectra in a first test to study how the dynamics of the TR are driven by the highly dynamic photospheric magnetic fields and the ubiquitous chromospheric waves. Initial analysis shows that these connections are quite subtle and require a combination of techniques including magnetic field extrapolations, frequency-filtered time-series and comparisons with synthetic chromospheric and TR images from advanced 3D numerical simulations. As a first result, we find signatures of magnetic flux emergence as well as 3 and 5 mHz wave power above regions of enhanced photospheric magnetic field in both chromospheric, transition region and coronal emission.
Quasi-static and Quasi-dynamic Modeling of Earthquake Failure at Intermediate Scales
Ben-Zion, Yehuda
Quasi-static and Quasi-dynamic Modeling of Earthquake Failure at Intermediate Scales GERT ZO¨ LLER1 of the regions around the fault, static/ kinetic friction laws with possible gradual healing, and stress transfer based on the solution of CHINNERY (1963) for static dislocations in an elastic half-space. As a new
Deep Learning Helicopter Dynamics Models Ali Punjani and Pieter Abbeel
Abbeel, Pieter
Deep Learning Helicopter Dynamics Models Ali Punjani and Pieter Abbeel Abstract-- We consider the problem of system identification of helicopter dynamics. Helicopters are complex systems, cou- pling rigid inspiration from recent results in Deep Learning to represent the helicopter dynamics with a Rectified Linear
Dynamical Reduction Models with General Gaussian Noises
Angelo Bassi; GianCarlo Ghirardi
2002-01-27
We consider the effect of replacing in stochastic differential equations leading to the dynamical collapse of the statevector, white noise stochastic processes with non white ones. We prove that such a modification can be consistently performed without altering the most interesting features of the previous models. One of the reasons to discuss this matter derives from the desire of being allowed to deal with physical stochastic fields, such as the gravitational one, which cannot give rise to white noises. From our point of view the most relevant motivation for the approach we propose here derives from the fact that in relativistic models the occurrence of white noises is the main responsible for the appearance of untractable divergences. Therefore, one can hope that resorting to non white noises one can overcome such a difficulty. We investigate stochastic equations with non white noises, we discuss their reduction properties and their physical implications. Our analysis has a precise interest not only for the above mentioned subject but also for the general study of dissipative systems and decoherence.
responses of human systems. This project seeks to apply a regional IAM framework to the Gulf Coast region issues, and energy supply issues are all occurring simultaneous- ly, but for which integrated modeling regionalized to develop a new regional IAM capability (Regional Global Change Assessment Model *RCGAM+). RCGAM
California Wintertime Precipitation in Regional and Global Climate Models
Caldwell, P M
2009-04-27
In this paper, wintertime precipitation from a variety of observational datasets, regional climate models (RCMs), and general circulation models (GCMs) is averaged over the state of California (CA) and compared. Several averaging methodologies are considered and all are found to give similar values when model grid spacing is less than 3{sup o}. This suggests that CA is a reasonable size for regional intercomparisons using modern GCMs. Results show that reanalysis-forced RCMs tend to significantly overpredict CA precipitation. This appears to be due mainly to overprediction of extreme events; RCM precipitation frequency is generally underpredicted. Overprediction is also reflected in wintertime precipitation variability, which tends to be too high for RCMs on both daily and interannual scales. Wintertime precipitation in most (but not all) GCMs is underestimated. This is in contrast to previous studies based on global blended gauge/satellite observations which are shown here to underestimate precipitation relative to higher-resolution gauge-only datasets. Several GCMs provide reasonable daily precipitation distributions, a trait which doesn't seem tied to model resolution. GCM daily and interannual variability is generally underpredicted.
From quantum to classical dynamics: Dynamic crossover in the relativistic $O(N)$ model
Mesterházy, David; Tanizaki, Yuya
2015-01-01
We investigate the transition from quantum to classical dynamics in the relativistic $O(N)$ vector model using the nonperturbative functional renormalization group in the real-time formalism. In thermal equilibrium, the theory is characterized by two scales, the interaction range for coherent scattering of particles and the mean free path determined by the rate of incoherent collision with excitations in the thermal medium. Their competition determines the renormalization group flow and the effective dynamics of the model. Here we quantify the dynamic properties of the model in terms of the scale-dependent dynamic critical exponent $z$ for arbitrary temperatures and in $2 \\leq d \\leq 4$ spatial dimensions.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Prein, Andreas; Langhans, Wolfgang; Fosser, Giorgia; Ferrone, Andrew; Ban, Nikolina; Goergen, Klaus; Keller, Michael; Tolle, Merja; Gutjahr, Oliver; Feser, Frauke; et al
2015-05-27
Regional climate modeling using convection permitting models (CPMs) emerges as a promising framework to provide more reliable climate information on regional to local scales compared to traditionally used large-scale models (LSMs). CPMs do not use convection parameterization schemes, known as a major source of errors and uncertainties, and have more accurate surface and orography elds. The drawback of CPMs is their high demand on computational resources. For this reason, the CPM climate simulations only appeared a decade ago. In this study we aim to provide a common basis for CPM climate simulations by giving a holistic review of the topic.more »The most important components in CPM, such as physical parameterizations and dynamical formulations are discussed, and an outlook on required future developments and computer architectures that would support the application of CPMs is given. Most importantly, this review presents the consolidated outcome of studies that addressed the added value of CPM climate simulations compared to LSMs. Most improvements are found for processes related to deep convection (e.g., precipitation during summer), for mountainous regions, and for the soil-vegetation-atmosphere interactions. The climate change signals of CPM simulations reveal increases in short and extreme rainfall events and an increased ratio of liquid precipitation at the surface (a decrease of hail) potentially leading to more frequent ash oods. Concluding, CPMs are a very promising tool for future climate research. However, coordinated modeling programs are crucially needed to assess their full potential and support their development.« less
A Dynamic Network Oligopoly Model Transportation Costs, Product Differentiation,
Nagurney, Anna
and Operations Management Isenberg School of Management University of Massachusetts Amherst, Massachusetts 01003A Dynamic Network Oligopoly Model with Transportation Costs, Product Differentiation, and Quality Network Oligopoly Model with Quality Competition #12;Acknowledgments This research was supported, in part
Continuous VRML output fromContinuous VRML output from regional circulation models: aregional and volume to viewview ·· Generate Virtual Reality Modeling LanguageGenerate Virtual Reality ModelingDesktop or laptop PC with web browser High speed/large RAM not essentialHigh speed/large RAM not essential
Learning vehicular dynamics, with application to modeling helicopters
Thrun, Sebastian
Learning vehicular dynamics, with application to modeling helicopters Pieter Abbeel Computer Abstract We consider the problem of modeling a helicopter's dynamics based on stateaction trajectories such as learned by CIFER (the industry standard in helicopter identification), and show that the linear
Learning vehicular dynamics, with application to modeling helicopters
Thrun, Sebastian
Learning vehicular dynamics, with application to modeling helicopters Pieter Abbeel Computer Abstract We consider the problem of modeling a helicopter's dynamics based on state-action trajectories such as learned by CIFER (the industry standard in helicopter identification), and show that the linear
Static and Impulsive Models of Solar Active Regions
S. Patsourakos; J. A. Klimchuk
2008-08-20
The physical modeling of active regions (ARs) and of the global coronal is receiving increasing interest lately. Recent attempts to model ARs using static equilibrium models were quite successful in reproducing AR images of hot soft X-ray (SXR) loops. They however failed to predict the bright EUV warm loops permeating ARs: the synthetic images were dominated by intense footpoint emission. We demonstrate that this failure is due to the very weak dependence of loop temperature on loop length which cannot simultaneously account for both hot and warm loops in the same AR. We then consider time-dependent AR models based on nanoflare heating. We demonstrate that such models can simultaneously reproduce EUV and SXR loops in ARs. Moreover, they predict radial intensity variations consistent with the localized core and extended emissions in SXR and EUV AR observations respectively. We finally show how the AR morphology can be used as a gauge of the properties (duration, energy, spatial dependence, repetition time) of the impulsive heating.
Dynamic Modeling in Solid-Oxide Fuel Cells Controller Design
Lu, Ning; Li, Qinghe; Sun, Xin; Khaleel, Mohammad A.
2007-06-28
In this paper, a dynamic model of the solid-oxide fuel cell (SOFC) power unit is developed for the purpose of designing a controller to regulate fuel flow rate, fuel temperature, air flow rate, and air temperature to maintain the SOFC stack temperature, fuel utilization rate, and voltage within operation limits. A lumped model is used to consider the thermal dynamics and the electro-chemial dynamics inside an SOFC power unit. The fluid dynamics at the fuel and air inlets are considered by using the in-flow ramp-rates.
MODELING SUPER-FAST MAGNETOSONIC WAVES OBSERVED BY SDO IN ACTIVE REGION FUNNELS
Ofman, L.; Liu, W.; Title, A.; Aschwanden, M.
2011-10-20
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.
Ye, Sheng; Li, Hongyi; Huang, Maoyi; Ali, Melkamu; Leng, Guoyong; Leung, Lai-Yung R.; Wang, Shaowen; Sivapalan, Murugesu
2014-07-21
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.
Lei, Huimin; Yang, Dawen; Huang, Maoyi
2014-04-16
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.
A multiscale MDCT image-based breathing lung model with time-varying regional ventilation
Yin, Youbing, E-mail: youbing-yin@uiowa.edu [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States) [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States); IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242 (United States); Department of Radiology, The University of Iowa, Iowa City, IA 52242 (United States); Choi, Jiwoong, E-mail: jiwoong-choi@uiowa.edu [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States) [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States); IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242 (United States); Hoffman, Eric A., E-mail: eric-hoffman@uiowa.edu [Department of Radiology, The University of Iowa, Iowa City, IA 52242 (United States); Department of Biomedical Engineering, The University of Iowa, Iowa City, IA 52242 (United States); Department of Internal Medicine, The University of Iowa, Iowa City, IA 52242 (United States); Tawhai, Merryn H., E-mail: m.tawhai@auckland.ac.nz [Auckland Bioengineering Institute, The University of Auckland, Auckland (New Zealand); Lin, Ching-Long, E-mail: ching-long-lin@uiowa.edu [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States) [Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, IA 52242 (United States); IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242 (United States)
2013-07-01
A novel algorithm is presented that links local structural variables (regional ventilation and deforming central airways) to global function (total lung volume) in the lung over three imaged lung volumes, to derive a breathing lung model for computational fluid dynamics simulation. The algorithm constitutes the core of an integrative, image-based computational framework for subject-specific simulation of the breathing lung. For the first time, the algorithm is applied to three multi-detector row computed tomography (MDCT) volumetric lung images of the same individual. A key technique in linking global and local variables over multiple images is an in-house mass-preserving image registration method. Throughout breathing cycles, cubic interpolation is employed to ensure C{sub 1} continuity in constructing time-varying regional ventilation at the whole lung level, flow rate fractions exiting the terminal airways, and airway deformation. The imaged exit airway flow rate fractions are derived from regional ventilation with the aid of a three-dimensional (3D) and one-dimensional (1D) coupled airway tree that connects the airways to the alveolar tissue. An in-house parallel large-eddy simulation (LES) technique is adopted to capture turbulent-transitional-laminar flows in both normal and deep breathing conditions. The results obtained by the proposed algorithm when using three lung volume images are compared with those using only one or two volume images. The three-volume-based lung model produces physiologically-consistent time-varying pressure and ventilation distribution. The one-volume-based lung model under-predicts pressure drop and yields un-physiological lobar ventilation. The two-volume-based model can account for airway deformation and non-uniform regional ventilation to some extent, but does not capture the non-linear features of the lung.
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
Generic solar photovoltaic system dynamic simulation model specification.
Ellis, Abraham; Behnke, Michael Robert; Elliott, Ryan Thomas
2013-10-01
This document is intended to serve as a specification for generic solar photovoltaic (PV) system positive-sequence dynamic models to be implemented by software developers and approved by the WECC MVWG for use in bulk system dynamic simulations in accordance with NERC MOD standards. Two specific dynamic models are included in the scope of this document. The first, a Central Station PV System model, is intended to capture the most important dynamic characteristics of large scale (> 10 MW) PV systems with a central Point of Interconnection (POI) at the transmission level. The second, a Distributed PV System model, is intended to represent an aggregation of smaller, distribution-connected systems that comprise a portion of a composite load that might be modeled at a transmission load bus.
The challenges of modelling antibody repertoire dynamics in HIV infection
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Luo, Shishi; Perelson, Alan S.
2015-07-20
Antibody affinity maturation by somatic hypermutation of B-cell immunoglobulin variable region genes has been studied for decades in various model systems using well-defined antigens. While much is known about the molecular details of the process, our understanding of the selective forces that generate affinity maturation are less well developed, particularly in the case of a co-evolving pathogen such as HIV. Despite this gap in understanding, high-throughput antibody sequence data are increasingly being collected to investigate the evolutionary trajectories of antibody lineages in HIV-infected individuals. Here, we review what is known in controlled experimental systems about the mechanisms underlying antibody selectionmore »and compare this to the observed temporal patterns of antibody evolution in HIV infection. In addition, we describe how our current understanding of antibody selection mechanisms leaves questions about antibody dynamics in HIV infection unanswered. Without a mechanistic understanding of antibody selection in the context of a co-evolving viral population, modelling and analysis of antibody sequences in HIV-infected individuals will be limited in their interpretation and predictive ability.« less
Improvement of snowpack simulations in a regional climate model
Jin, J.; Miller, N.L.
2011-01-10
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.
Steady-State Dynamics of the Forest Fire Model on Complex Networks
Bancal, Jean-Daniel
2009-01-01
Many sociological networks, as well as biological and technological ones, can be represented in terms of complex networks with a heterogeneous connectivity pattern. Dynamical processes taking place on top of them can be very much influenced by this topological fact. In this paper we consider a paradigmatic model of non-equilibrium dynamics, namely the forest fire model, whose relevance lies in its capacity to represent several epidemic processes in a general parametrization. We study the behavior of this model in complex networks by developing the corresponding heterogeneous mean-field theory and solving it in its steady state. We provide exact and approximate expressions for homogeneous networks and several instances of heterogeneous networks. A comparison of our analytical results with extensive numerical simulations allows to draw the region of the parameter space in which heterogeneous mean-field theory provides an accurate description of the dynamics, and enlights the limits of validity of the mean-field...
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 Sřrensen, Nicolaos Cutululis, Clemens Jauch, Frede Blaabjerg Title: Dynamic wind turbine system simulation tool PowerFactory DIgSILENT for different wind turbine concepts. It is the second
Novel Dynamical Modeling for Series-Parallel Resonant Converter
Noé, Reinhold
and voltage waveforms in the resonant tank are assumed to be sinusoidal. Using this approach steady enables accurate calculation of steady-state characteristics under all (light to heavy) load conditions. For studying the dynamical behavior of the SPRC and for control design dynamical modeling techniques
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
Stochastic modeling of lift and drag dynamics under turbulent conditions
Peinke, Joachim
Matthias Wächter Joachim Peinke ForWind - Center for Wind Energy Research University of Oldenburg, Germany measurement. The model is being developed with the aim to integrate it into a general wind energy converter dynamics, drag dynamics. 1 Introduction Wind energy converters (WECs) are permanently exposed to turbulent
Comparing Families of Dynamic Causal Models Will D. Penny1
Daunizeau, Jean
Comparing Families of Dynamic Causal Models Will D. Penny1 *, Klaas E. Stephan1,2 , Jean Daunizeau1: Penny WD, Stephan KE, Daunizeau J, Rosa MJ, Friston KJ, et al. (2010) Comparing Families of Dynamic, 2010; Published March 12, 2010 Copyright: Ă? 2010 Penny et al. This is an open-access article
Aging of asymmetric dynamics on the random energy model
Pierre Mathieu; Jean-Christophe Mourrat
2013-03-20
We show aging of Glauber-type dynamics on the random energy model, in the sense that we obtain the scaling limits of the clock process and of the age process. The latter encodes the Gibbs weight of the configuration occupied by the dynamics. Both limits are expressed in terms of stable subordinators.
Dynamic Simulation Model of a Consumer Foods Production Process !
Sun, Yu
schedule based on product list The SIMUL8 Component 1. Over 200 lines of simula0on code 2. ReadsDynamic Simulation Model of a Consumer Foods Production Process ! Goals · Create a dynamic simula0 Created par0ally automated Excel files to go handin hand with simula0on o Contains all SKUs and meat
Dynamic Modelling for Control of Fuel Cells Federico Zenith
Skogestad, Sigurd
Dynamic Modelling for Control of Fuel Cells Federico Zenith Sigurd Skogestad Department of Chemical Engineering Norwegian University of Science and Technology ( ntnu) Trondheim Abstract Fuel-cell dynamics have been investigated with a variable-resistance board applied to a high temperature polymer fuel cell
REGULAR ARTICLE A Simple Dynamic Model of Respiratory Pump
Fontecave-Jallon, Julie
REGULAR ARTICLE A Simple Dynamic Model of Respiratory Pump Pascale Calabrese · Pierre Baconnier the relative motion of rib cage and abdomen during quiet breathing. Keywords Respiratory pump model Á. Hillman and Finucane (1987) have produced a simple model of the respiratory pump that ``appears
A Diffusion Model in Population Genetics with Mutation and Dynamic
O'Leary, Michael
A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness Mike O'Leary Department of Mathematics Towson University May 24, 2008 Mike O'Leary (Towson University) A Diffusion Model in Genetics May Miller, Georgetown University Mike O'Leary (Towson University) A Diffusion Model in Genetics May 24, 2008
COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS
COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS Ugur Pasaogullari and Chao-dimensional model has been developed to simulate solid oxide fuel cells (SOFC). The model fully couples current density operation. INTRODUCTION Solid oxide fuel cells (SOFC) are among possible candidates
A Compositional and Dynamic Model for Face Aging
Zhu, Song Chun
A Compositional and Dynamic Model for Face Aging Jinli Suo, Song-Chun Zhu, Shiguang Shan, Member model for face aging. The compositional model represents faces in each age group by a hierarchical And.) crucial for age perception and Or nodes represent large diversity of faces by alternative selections
A Dynamic Island Model for Adaptive Operator Selection Caner Candan
Goëffon, Adrien
A Dynamic Island Model for Adaptive Operator Selection Caner Candan LERIA - University of Angers Angers, France caner.candan@univ-angers.fr Adrien Goëffon LERIA - University of Angers Angers, France
Applications of axial and radial compressor dynamic system modeling
Spakovszky, Zoltán S. (Zoltán Sándor), 1972-
2001-01-01
The presented work is a compilation of four different projects related to axial and centrifugal compression systems. The projects are related by the underlying dynamic system modeling approach that is common in all of them. ...
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 ...
Modeling and control of undesirable dynamics in atomic force microscopes
El Rifai, Osamah M
2002-01-01
The phenomenal resolution and versatility of the atomic force microscope (AFM), has made it a widely-used instrument in nanotechnology. In this thesis, a detailed model of AFM dynamics has been developed. It includes a new ...
Model reduction for nonlinear dynamical systems with parametric uncertainties
Zhou, Yuxiang Beckett
2012-01-01
Nonlinear dynamical systems are known to be sensitive to input parameters. In this thesis, we apply model order reduction to an important class of such systems -- one which exhibits limit cycle oscillations (LCOs) and ...
Off-line calibration of Dynamic Traffic Assignment models
Balakrishna, Ramachandran, 1978-
2006-01-01
Advances in Intelligent Transportation Systems (ITS) have resulted in the deployment of surveillance systems that automatically collect and store extensive network-wide traffic data. Dynamic Traffic Assignment (DTA) models ...
Transmission Dynamics of an Influenza Model with Age of Infection ...
2010-07-20
J Dyn Diff Equat. DOI 10.1007/s10884-010-9178-x. Transmission Dynamics of an Influenza Model with Age of Infection and Antiviral Treatment. Zhipeng Qiu ...
Multi-resolution modeling of the dynamic loading of metal matrix...
Office of Scientific and Technical Information (OSTI)
Journal Article: Multi-resolution modeling of the dynamic loading of metal matrix composites. Citation Details In-Document Search Title: Multi-resolution modeling of the dynamic...
Developing Generic Dynamic Models for the 2030 Eastern Interconnection Grid
Kou, Gefei; Hadley, Stanton W; Markham, Penn N; Liu, Yilu
2013-12-01
The Eastern Interconnection Planning Collaborative (EIPC) has built three major power flow cases for the 2030 Eastern Interconnection (EI) based on various levels of energy/environmental policy conditions, technology advances, and load growth. Using the power flow cases, this report documents the process of developing the generic 2030 dynamic models using typical dynamic parameters. The constructed model was validated indirectly using the synchronized phasor measurements by removing the wind generation temporarily.
Chen, Shu-Hua
will stress water resources, impact energy supply and demand, challenge crop and livestock pro & Forecasting) model. The dynamical downscaling was performed to both the GFS (Global forecast model) reanalysis
Dynamic reactor modeling with applications to SPR and ZEDNA.
Suo-Anttila, Ahti Jorma
2011-12-01
A dynamic reactor model has been developed for pulse-type reactor applications. The model predicts reactor power, axial and radial fuel expansion, prompt and delayed neutron population, and prompt and delayed gamma population. All model predictions are made as a function of time. The model includes the reactivity effect of fuel expansion on a dynamic timescale as a feedback mechanism for reactor power. All inputs to the model are calculated from first principles, either directly by solving systems of equations, or indirectly from Monte Carlo N-Particle Transport Code (MCNP) derived results. The model does not include any empirical parameters that can be adjusted to match experimental data. Comparisons of model predictions to actual Sandia Pulse Reactor SPR-III pulses show very good agreement for a full range of pulse magnitudes. The model is also applied to Z-pinch externally driven neutron assembly (ZEDNA) type reactor designs to model both normal and off-normal ZEDNA operations.
Mesoscale modeling of phase transition dynamics of thermoresponsive polymers
Li, Zhen; Li, Xuejin; Karniadakis, George Em
2015-01-01
We present a non-isothermal mesoscopic model for investigation of the phase transition dynamics of thermoresponsive polymers. Since this model conserves energy in the simulations, it is able to correctly capture not only the transient behavior of polymer precipitation from solvent, but also the energy variation associated with the phase transition process. Simulations provide dynamic details of the thermally induced phase transition and confirm two different mechanisms dominating the phase transition dynamics. A shift of endothermic peak with concentration is observed and the underlying mechanism is explored.
Dynamic competition model for construction contractors
Kim, Hyung Jin
2004-01-01
as an entity in a dynamic system, in which every entity is a profit optimizer responding to market conditions as well as its competitors' actions. In construction, the issue of competition has been focused on competitive bidding, which is a critical mechanism...
The dynamical structure of the MEO region: long-term stability, chaos, and transport
Daquin, Jerome; Deleflie, Florent; Alessi, Elisa Maria; Valsecchi, Giovanni B; Rossi, Alessandro
2015-01-01
It has long been suspected that the Global Navigation Satellite Systems exist in a background of complex resonances and chaotic motion; yet, the precise dynamical character of these phenomena remains elusive. Recent studies have shown that the occurrence and nature of the resonances driving these dynamics depend chiefly on the frequencies of nodal and apsidal precession and the rate of regression of the Moon's nodes. Woven throughout the inclination and eccentricity phase space is an exceedingly complicated web-like structure of lunisolar secular resonances, which become particularly dense near the inclinations of the navigation satellite orbits. A clear picture of the physical significance of these resonances is of considerable practical interest for the design of disposal strategies for the four constellations. Here we present analytical and semi-analytical models that accurately reflect the true nature of the resonant interactions, and trace the topological organization of the manifolds on which the chaoti...
A stochastic evolutionary model for capturing human dynamics
Fenner, Trevor; Loizou, George
2015-01-01
The recent interest in human dynamics has led researchers to investigate the stochastic processes that explain human behaviour in various contexts. Here we propose a generative model to capture the dynamics of survival analysis, traditionally employed in clinical trials and reliability analysis in engineering. We derive a general solution for the model in the form of a product, and then a continuous approximation to the solution via the renewal equation describing age-structured population dynamics. This enables us to model a wide rage of survival distributions, according to the choice of the mortality distribution. We provide empirical evidence for the validity of the model from a longitudinal data set of popular search engine queries over 114 months, showing that the survival function of these queries is closely matched by the solution for our model with power-law mortality.
Structure formation: Models, Dynamics and Status
T. Padmanabhan
1995-08-25
The constraints on the models for the structure formation arising from various cosmological observations at different length scales are reviewed. The status of different models for structure formation is examined critically in the light of these observations.
Modeling emotion dynamics in intelligent agents
Seif El-Nasr, Magy
1998-01-01
Emotions were shown to have a leading role in the human decision-making process, and thus they play an important role in human intelligence. Intelligent agents' research produced many models of emotional agents. However, most of these models focused...
Breazeale, K.; Isaak, D.T.; Yamaguchi, N.; Fridley, D.; Johnson, C.; Long, S.
1993-12-01
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.
Patrick B. Warren; Andrey Vlasov
2014-02-25
We extend our previous study [J. Chem. Phys. 138, 204907 (2013)] to quantify the screening properties of four mesoscale smoothed charge models used in dissipative particle dynamics. Using a combination of the hypernetted chain integral equation closure and the random phase approximation, we identify regions where the models exhibit a real-valued screening length, and the extent to which this agrees with the Debye length in the physical system. We find that the second moment of the smoothed charge distribution is a good predictor of this behaviour. We are thus able to recommend a consistent set of parameters for the models.
Sloan, Lisa C
2005-01-01
4) Central Coast; (5) Tulare Lake; (6) San Joaquin; (7) San4) Central Coast, (5) Tulare Lake, (6) San Joaquin River, (the smallest increase is in the Tulare Lake region. Median
A survey and a molecular dynamics study on the (central) hydrophobic region of prion proteins
Zhang, Jiapu
2014-01-01
Prion diseases are invariably fatal neurodegenerative diseases that affect humans and animals. Unlike most other amyloid forming neurodegenerative diseases, these can be highly infectious. Prion diseases occur in a variety of species. They include the fatal human neurodegenerative diseases Creutzfeldt-Jakob Disease (CJD), Fatal Familial Insomnia (FFI), Gerstmann-Straussler-Scheinker syndrome (GSS), Kuru, the bovine spongiform encephalopathy (BSE or 'mad-cow' disease) in cattle, the chronic wasting disease (CWD) in deer and elk, and scrapie in sheep and goats, etc. Transmission across the species barrier to humans, especially in the case of BSE in Europe, CWD in North America, and variant CJDs (vCJDs) in young people of UK, is a major public health concern. Fortunately, scientists reported that the (central) hydrophobic region of prion proteins (PrP) controls the formation of diseased prions. This article gives a detailed survey on PrP hydrophobic region and does molecular dynamics studies of human PrP(110-136...
Computational Fluid Dynamics (CFD) Modelling on Soot Yield for Fire
Computational Fluid Dynamics (CFD) Modelling on Soot Yield for Fire Engineering Assessment Yong S (CFD) Modelling is now widely used by fire safety engineers throughout the world as a tool of the smoke control design as part of the performance based fire safety design in the current industry
Dislocation dynamics: from microscopic models to macroscopic crystal plasticity
El Hajj, Ahmad
Dislocation dynamics: from microscopic models to macroscopic crystal plasticity A. El Hajj , H study ranges from atomic models to macroscopic crystal plasticity. At each scale, dislocations can crystal Z3 where each position with integer coordinates is occupied by one atom. We want to describe
Fluid Dynamic Models of Flagellar and Ciliary Beating
Fauci, Lisa
University, New Orleans, Louisiana, USA ABSTRACT: We have developed a fluidmechanical model of a eucaryotic mechanics of microtubules, and forces due to nexin links with a surrounding incompressible fluid. This model mechanisms, the passive elastic structure of the axoneme, and the external fluid dynamics. These flagellar
SIMULATING MARKET TRANSFORMATION DYNAMICS USING A HYBRID ENERGY ECONOMY MODEL
ii SIMULATING MARKET TRANSFORMATION DYNAMICS USING A HYBRID ENERGY ECONOMY MODEL: A LOOK the likely effects of alternative policies, potential adoption rates of clean technologies, and costs to society in the long run. My goal was to use a "hybrid" energy economy model (CIMS), which combines
A STOCHASTIC CELLULAR AUTOMATON MODEL OF EBOLA VIRUS DYNAMICS
Hawkins, Jane M.
A STOCHASTIC CELLULAR AUTOMATON MODEL OF EBOLA VIRUS DYNAMICS E. BURKHEAD AND J. HAWKINS Abstract. We construct a stochastic cellular automaton (SCA) model for the spread of the Ebola virus (EBOV). We of virus and the typical immune response to it, and the differences which reflect the drastically different
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
A Dynamic Model coupling Photoacclimation and Photoinhibition in Microalgae
Boyer, Edmond
in microalgae, thereby spanning multiple time scales. The properties of the model are investigated under quasi2 mitigation due to their inherent consumption of CO2 during photosynthesis, they can be coupledA Dynamic Model coupling Photoacclimation and Photoinhibition in Microalgae Philipp Hartmann1
Numerically Estimating Internal Models of Dynamic Virtual Objects
Sekuler, Robert
human subjects to manipulate a computer-animated virtual object. This virtual object (vO) was a high, human cognition, human information processing, ideal performer, internal model, virtual object, virtual, specifically how humans acquire an internal model of a dynamic virtual object. Our methodology minimizes
Modeling and simulation of consumer response to dynamic pricing.
Valenzuela, J.; Thimmapuram, P.; Kim, J (Decision and Information Sciences); (Auburn Univ.)
2012-08-01
Assessing the impacts of dynamic-pricing under the smart grid concept is becoming extremely important for deciding its full deployment. In this paper, we develop a model that represents the response of consumers to dynamic pricing. In the model, consumers use forecasted day-ahead prices to shift daily energy consumption from hours when the price is expected to be high to hours when the price is expected to be low while maintaining the total energy consumption as unchanged. We integrate the consumer response model into the Electricity Market Complex Adaptive System (EMCAS). EMCAS is an agent-based model that simulates restructured electricity markets. We explore the impacts of dynamic-pricing on price spikes, peak demand, consumer energy bills, power supplier profits, and congestion costs. A simulation of an 11-node test network that includes eight generation companies and five aggregated consumers is performed for a period of 1 month. In addition, we simulate the Korean power system.
Dynamical many-body localization in an integrable model
Aydin Cem Keser; Sriram Ganeshan; Gil Refael; Victor Galitski
2015-06-17
We investigate dynamical many-body localization and delocalization in an integrable system of periodically-kicked, interacting linear rotors. The Hamiltonian we investigate is linear in momentum, and its Floquet evolution operator is analytically tractable for arbitrary interaction strengths. One of the hallmarks of this model is that depending on certain parameters, it manifest both localization and delocalization in momentum space. We explicitly show that, for this model, the energy being bounded at long times is not a sufficient condition for dynamical localization. Besides integrals of motion associated to the integrability, this model manifests additional integrals of motion, which are the exclusive consequence of dynamical many-body localization. We also propose an experimental scheme, involving voltage-biased Josephson junctions, to realize such many-body kicked models.
DYNAMICAL MODEL OF AN EXPANDING SHELL
Pe'er, Asaf [Harvard-Smithsonian Center for Astrophysics, MS-51, 60 Garden Street, Cambridge, MA 02138 (United States)
2012-06-10
Expanding blast waves are ubiquitous in many astronomical sources, such as supernova remnants, X-ray emitting binaries, and gamma-ray bursts. I consider here the dynamics of such an expanding blast wave, both in the adiabatic and the radiative regimes. As the blast wave collects material from its surroundings, it decelerates. A full description of the temporal evolution of the blast wave requires consideration of both the energy density and the pressure of the shocked material. The obtained equation is different from earlier works in which only the energy was considered. The solution converges to the familiar results in both the ultrarelativistic and the sub-relativistic (Newtonian) regimes.
Deep ACS Imaging in the Globular Cluster NGC6397: Dynamical Models
Jarrod R. Hurley; Michael M. Shara; Harvey B. Richer; Ivan R. King; D. Saul Davis; Jason S. Kalirai; Brad M. S. Hansen; Aaron Dotter; Jay Anderson; Gregory G. Fahlman; R. Michael Rich
2008-02-28
We present N-body models to complement deep imaging of the metal-poor core-collapsed cluster NGC6397 obtained with the Hubble Space Telescope. All simulations include stellar and binary evolution in-step with the stellar dynamics and account for the tidal field of the Galaxy. We focus on the results of a simulation that began with 100000 objects (stars and binaries), 5% primordial binaries and Population II metallicity. After 16 Gyr of evolution the model cluster has about 20% of the stars remaining and has reached core-collapse. We compare the color-magnitude diagrams of the model at this age for the central region and an outer region corresponding to the observed field of NGC6397 (about 2-3 half-light radii from the cluster centre). This demonstrates that the white dwarf population in the outer region has suffered little modification from dynamical processes - contamination of the luminosity function by binaries and white dwarfs with non-standard evolution histories is minimal and should not significantly affect measurement of the cluster age. We also show that the binary fraction of main-sequence stars observed in the NGC6397 field can be taken as representative of the primordial binary fraction of the cluster. For the mass function of the main-sequence stars we find that although this has been altered significantly by dynamics over the cluster lifetime, especially in the central and outer regions, that the position of the observed field is close to optimal for recovering the initial mass function of the cluster stars (below the current turn-off mass). More generally we look at how the mass function changes with radius in a dynamically evolved stellar cluster and suggest where the best radial position to observe the initial mass function is for clusters of any age.
Slow dynamics in a model of the cellulose network
O. V. Manyuhina; A. Fasolino; M. I. Katsnelson
2007-06-07
We present numerical simulations of a model of cellulose consisting of long stiff rods, representing cellulose microfibrils, connected by stretchable crosslinks, representing xyloglucan molecules, hydrogen bonded to the microfibrils. Within a broad range of temperature the competing interactions in the resulting network give rise to a slow glassy dynamics. In particular, the structural relaxation described by orientational correlation functions shows a logarithmic time dependence. The glassy dynamics is found to be due to the frustration introduced by the network of xyloglucan molecules. Weakening of interactions between rod and xyloglucan molecules results in a more marked reorientation of cellulose microfibrils, suggesting a possible mechanism to modify the dynamics of the plant cell wall.
A Dynamic Solar Core Model: On the Activity-Related Changes of the Neutrino Fluxes
Attila Grandpierre
1998-10-08
The energy sources of the Sun may actually involve a thermonuclear runaway energy source present in stellar energy producing regions. I consider the conjectures of the derived model for the solar neutrino fluxes in case of a solar core allowed to vary in relation to the surface activity cycle. The observed neutrino flux data suggest a solar core possibly varying in time. In the dynamic solar model the quiet and runaway energy sources together may produce quasi-constant flux in the SuperKamiokande because it is sensitive to neutral currents, axions and anti-neutrinos, too. I calculate the contributions of the runaway source to the individual neutrino detectors. The results of the dynamic solar core model suggest that since the HOMESTAKE detects mostly the high energy electron neutrinos, therefore the HOMESTAKE data may aniticorrelate with the activity cycle. Activity correlated changes are expected to be present only marginally in the GALLEX and GNO data. The gallium detectors are sensitive mostly to the pp neutrinos, and the changes of the pp neutrinos arising from the SSM-like core is mostly compensated by the high-energy electron neutrinos produced by the hot bubbles of the dynamic energy source. The results suggest that the GALLEX data may show an anti-correlation, while the SuperKamiokande data may show a correlation with the activity cycle. Predictions of the dynamic solar model are presented for the SNO and Borexino experiments which can distinguish between the effects of the MSW mechanism and the consequences of the dynamic solar model. The results of the dynamic solar model are consistent with the present heioseismic measurements and can be checked with future heioseismic measurements as well. Keywords: solar neutrino problems - solar activity - thermonuclear runaways
STOCHASTIC DYNAMICS OF A COUPLED ATMOSPHEREOCEAN MODEL
's longwave radiation coefficient and the shortwave solar radiation profile. Third, we have demon- strated this coupled atmosphere-ocean model consists of stochastic Date: February 5, 2002. 1991 Mathematics Subject
Generative modeling of dynamic visual scenes
Lin, Dahua, Ph. D. Massachusetts Institute of Technology
2012-01-01
Modeling visual scenes is one of the fundamental tasks of computer vision. Whereas tremendous efforts have been devoted to video analysis in past decades, most prior work focuses on specific tasks, leading to dedicated ...
Modeling Infection with Multi-agent Dynamics
Dong, Wen
2012-01-01
Developing the ability to comprehensively study infections in small populations enables us to improve epidemic models and better advise individuals about potential risks to their health. We currently have a limited ...
A regional numerical ocean model of the circulation in the Bay of Biscay
Drijfhout, Sybren
A regional numerical ocean model of the circulation in the Bay of Biscay Y. Friocourt,1,2,3 B Peninsula and in the Bay of Biscay is investigated by means of a regional ocean model. In particular numerical ocean model of the circulation in the Bay of Biscay, J. Geophys. Res., 112, C09008, doi:10
CSAW: a dynamical model of protein folding
Kerson Huang
2006-01-12
CSAW (conditioned self-avoiding walk) is a model of protein folding that combines SAW (self-avoiding walk) with Monte-Carlo. It simulates the Brownian motion of a chain molecule in the presence of interactions, both among chain residues, and with the environment. In a first model that includes the hydrophobic effect and hydrogen bonding, a chain of 30 residues folds into a native state with stable secondary and tertiary structures. The process starts with a rapid collapse into an intermediate "molten globule", which slowly decays into the native state afer a relatively long quiescent period. The behavior of the radius of gyration mimics experimental data.
Analytical properties of a three-compartmental dynamical demographic model
E. B. Postnikov
2015-07-29
The three-compartmental demographic model by Korotaeyv-Malkov-Khaltourina, connecting population size, economic surplus, and educational level, is considered from the point of view of dynamical systems theory. It is shown that there exist two integrals of motion, which enable the system to be reduced to one non-linear ordinary differential equation. The study of its structure provides analytical criteria for the dominance ranges of the dynamics of Malthus and Kremer. Additionally, the particular ranges of parameters enable the derived general ordinary differential equations to be reduced to the models of Gompertz and Thoularis-Wallace.
Model Based Safety Assessment Dynamic System
Grigoras, .Romulus
Assessment Techniques ·Failure mode and effect analysis (FMEA) Model: from a local failure to its system chain .... 2 Functional FMEA template FT unannunciated loss of wheel braking #12;Drawbacks of the Classical Safety Assessment Techniques · Fault Tree, FMEA Give failure propagation paths without referring
Modeled regional climate change and California endemic oak ranges
Kueppers, Lara M.
pressure from cutting for fuel, grazing, conversion of woodlands to vineyards and orchards, water resource development, competition with inva- sive grasses, and urban expansion (1). Here, we report how the regional
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)
2012-12-01
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.
Green Algae as Model Organisms for Biological Fluid Dynamics
Goldstein, Raymond E
2014-01-01
In the past decade the volvocine green algae, spanning from the unicellular $Chlamydomonas$ to multicellular $Volvox$, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 $\\mu$m to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these re...
Green Algae as Model Organisms for Biological Fluid Dynamics
Raymond E. Goldstein
2014-09-08
In the past decade the volvocine green algae, spanning from the unicellular $Chlamydomonas$ to multicellular $Volvox$, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 $\\mu$m to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these remarkable organisms.
Modeling Dynamic Landscapes in Open Source GIS
Mitasova, Helena
2013-11-20
is free online • message board discussion, help • Google sites: post HW, get feedback • register to get credit Solar radiation modeling: monthly totals Applications in urban areas: solar panels, building design, thermal conditions,… Helena Mitasova, NCSU... topics: • Solar energy potential • Coastal hazards • Watershed analysis • Trail and greenway design • Lidar data processing Most students use ArcGIS but number of students who use GRASS for at least part of their project is increasing every semester...
An efficient model of drillstring dynamics
Butlin, T.; Langley, R. S.
2015-07-23
Vibration problems represent a significant cost to the oilwell drilling industry due to a wide range of problematic phenomena that can occur [1]. Torsional vibration can cause fatigue, damage to the drillbit if the direction of rotation periodically reverses... ,14]). There are many other effects that could be included in a drillstring model, such as fluid-structure interaction, the effect of free particles at frictional and cutting interfaces, well-path tortu- osity, mud-pump excitation, and buckling. It is clear...
Hans Peter Schmid; Craig Wayson
2009-05-05
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 crack initiation toughness : experiments and peridynamic modeling.
Foster, John T.
2009-10-01
This is a dissertation on research conducted studying the dynamic crack initiation toughness of a 4340 steel. Researchers have been conducting experimental testing of dynamic crack initiation toughness, K{sub Ic}, for many years, using many experimental techniques with vastly different trends in the results when reporting K{sub Ic} as a function of loading rate. The dissertation describes a novel experimental technique for measuring K{sub Ic} in metals using the Kolsky bar. The method borrows from improvements made in recent years in traditional Kolsky bar testing by using pulse shaping techniques to ensure a constant loading rate applied to the sample before crack initiation. Dynamic crack initiation measurements were reported on a 4340 steel at two different loading rates. The steel was shown to exhibit a rate dependence, with the recorded values of K{sub Ic} being much higher at the higher loading rate. Using the knowledge of this rate dependence as a motivation in attempting to model the fracture events, a viscoplastic constitutive model was implemented into a peridynamic computational mechanics code. Peridynamics is a newly developed theory in solid mechanics that replaces the classical partial differential equations of motion with integral-differential equations which do not require the existence of spatial derivatives in the displacement field. This allows for the straightforward modeling of unguided crack initiation and growth. To date, peridynamic implementations have used severely restricted constitutive models. This research represents the first implementation of a complex material model and its validation. After showing results comparing deformations to experimental Taylor anvil impact for the viscoplastic material model, a novel failure criterion is introduced to model the dynamic crack initiation toughness experiments. The failure model is based on an energy criterion and uses the K{sub Ic} values recorded experimentally as an input. The failure model is then validated against one class of problems showing good agreement with experimental results.
STRUCTURAL VALIDATION OF SYSTEM DYNAMICS AND AGENT-BASED SIMULATION MODELS
Tesfatsion, Leigh
, population dynamics, energy systems, and urban planning. The usefulness of these models is predicated including global warming, population dynamics, energy systems, and urban planning simply defy a face
Usefulness of the reversible jump Markov chain Monte Carlo model in regional flood frequency
Ribatet, Mathieu
Usefulness of the reversible jump Markov chain Monte Carlo model in regional flood frequency; revised 3 May 2007; accepted 17 May 2007; published 3 August 2007. [1] Regional flood frequency analysis and the index flood approach. Results show that the proposed estimator is absolutely suited to regional
Evaluation of Reconstructed Images of Regional Lung Changes Using a Model
Adler, Andy
Evaluation of Reconstructed Images of Regional Lung Changes Using a Model Robert P, Patterson1 A and Patterson 2004, Yang and Patterson 2010). In order to answer questions about regional lung changes, two regions were created in the posterior portion of the right lung where the resistivity can be independently
Deep ACS Imaging in the Globular Cluster NGC6397: Dynamical Models
Hurley, Jarrod R; Richer, Harvey B; King, Ivan R; Davis, D Saul; Kalirai, Jason S; Hansen, Brad M S; Dotter, Aaron; Anderson, Jay; Fahlman, Gregory G; Rich, R Michael
2008-01-01
We present N-body models to complement deep imaging of the metal-poor core-collapsed cluster NGC6397 obtained with the Hubble Space Telescope. All simulations include stellar and binary evolution in-step with the stellar dynamics and account for the tidal field of the Galaxy. We focus on the results of a simulation that began with 100000 objects (stars and binaries), 5% primordial binaries and Population II metallicity. After 16 Gyr of evolution the model cluster has about 20% of the stars remaining and has reached core-collapse. We compare the color-magnitude diagrams of the model at this age for the central region and an outer region corresponding to the observed field of NGC6397 (about 2-3 half-light radii from the cluster centre). This demonstrates that the white dwarf population in the outer region has suffered little modification from dynamical processes - contamination of the luminosity function by binaries and white dwarfs with non-standard evolution histories is minimal and should not significantly a...
An intelligent floor field cellular automata model for pedestrian dynamics
Ekaterina Kirik; Tat'yana Yurgel'yan; Dmitriy Krouglov
2009-06-15
A stochastic cellular automata (CA) model for pedestrian dynamics is presented. Our goal is to simulate different types of pedestrian movement, from regular to panic. But here we emphasize regular situations which imply that pedestrians analyze environment and choose their route more carefully. And transition probabilities have to depict such effect. The potentials of floor fields and environment analysis are combined in the model obtained. People patience is included in the model. This makes simulation of pedestrians movement more realistic. Some simulation results are presented and comparison with basic FF-model is made.
Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction
Veatch, Michael H.
of approximating functions for the differential cost. The first contribution of this paper is identifying new or piece-wise quadratic. Fluid cost has been used to initialize the value iteration algorithm [5Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction Michael H
Counterclockwise Dynamics of a Rate-Independent Semilinear Duhem Model
Bernstein, Dennis S.
Counterclockwise Dynamics of a Rate-Independent Semilinear Duhem Model Ashwani K. Padthe, Jin of a hysteretic simple closed curve. In magnetics, hysteresis caused by the irreversible flux-change mechanism dissipates energy in the form of heat [2]. In both cases, the energy dissipated in one cycle is equal
Dynamic and Static Influence Models on Starbucks Networks Minkyoung Kim
Dynamic and Static Influence Models on Starbucks Networks Minkyoung Kim Interdisciplinary Program Starbucks stores in Korea, which have been spread most rapidly in the world, as an exemplary social network for Starbucks to open the 100th store in Korea, which is the fastest growth of Starbucks in the world [10
GLOBAL DYNAMICS OF AN SEIR EPIDEMIC MODEL WITH VERTICAL TRANSMISSION
Li, Michael
GLOBAL DYNAMICS OF AN SEIR EPIDEMIC MODEL WITH VERTICAL TRANSMISSION MICHAEL Y. LI, HAL L. SMITH population through both horizontal and vertical transmission. The total host population is assumed to have at an endemic equilibrium state if it initially exists. The contribution of the vertical transmission
Modeling Combined Time-and Event-Driven Dynamic Systems
Baclawski, Kenneth B.
such as logistical systems, distributed sensor sys- tems and intelligent highway vehicle systems, are complex dynamic. In this approach, future behaviors are generated through quantitative simulation which "executes" a simulation model, typically at fixed time steps, to obtain quantitative values of state and/or output variables. 1
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
Geographical Information Systems and Dynamic Modeling via Agent Based Systems
de Figueiredo, Luiz Henrique
Geographical Information Systems and Dynamic Modeling via Agent Based Systems Cláudio Antônio da fariasol@eng.uerj.br ABSTRACT A full integration among Geographical Information Systems and Agent Based integrated with Geographical Information Systems (GIS). The first one is the movement of pedestrians
Modelling microbial population dynamics in nitritation processes Elisabetta Giusti a
Modelling microbial population dynamics in nitritation processes Elisabetta Giusti a , Stefano. Marta 3, I-50139 Florence, Italy b ENEA, Italian National Agency for New Technologies, Energy January 2011 Accepted 1 February 2011 Available online 3 March 2011 Keywords: Microbial kinetics Activated
Lessons Learned from Quantitative Dynamical Modeling in Systems Biology
Timmer, Jens
Lessons Learned from Quantitative Dynamical Modeling in Systems Biology Andreas Raue1,2 *. , Marcel of Physics, University of Freiburg, Freiburg, Germany, 2 Institute of Computational Biology, Helmholtz Center, Munich, Germany, 3 Systems Biology of Signal Transduction, German Cancer Research Center
Transport coefficients of a mesoscopic fluid dynamics model
N. Kikuchi; C. M. Pooley; J. F. Ryder; J. M. Yeomans
2003-02-21
We investigate the properties of stochastic rotation dynamics (Malevanets-Kapral method), a mesoscopic model used for simulating fluctuating hydrodynamics. Analytical results are given for the transport coefficients. We discuss the most efficient way of measuring the transport properties and obtain excellent agreement between the theoretical and numerical calculations.
Parameterized Model Order Reduction of Nonlinear Dynamical Systems
Reif, Rafael
Parameterized Model Order Reduction of Nonlinear Dynamical Systems Brad Bond Research Laboratory reduction technique for non-linear systems. Our approach combines an existing non-parameterized trajectory piecewise linear method for non-linear systems, with an existing moment matching param- eterized technique
Modeling the Dynamic Interaction of Hebbian and Homeostatic Plasticity
Stryker, Michael
Neuron Article Modeling the Dynamic Interaction of Hebbian and Homeostatic Plasticity Taro.toyoizumi@brain.riken.jp http://dx.doi.org/10.1016/j.neuron.2014.09.036 SUMMARY Hebbian and homeostatic plasticity together of plasticity directly modifies synaptic strength. Equilibrium is reached when the two are inducing equal
Modelling of the static and dynamic mechanical properties of human
Haslwanter, Thomas
Modelling of the static and dynamic mechanical properties of human otoliths DISSERTATION zur of the city of Paris #12;#12;Abstract The aim of this study is a numerical investigation of the static in the inner ears. They sense accelerations of the head. In the static case, information retrieved from them
Dynamic Modelling and Control Design of Pre-combustion Power
Foss, Bjarne A.
principles. The pre- combustion gas power cycle plants consist of reformers and separation units, com and control design of two pre-combustion power cycles, i.e., a hydro- gen membrane reformer (HMR) based power- pressors, gas and steam turbines and a heat recovery system. Analysis of dynamic models at an early stage
Dynamical Model of Rocket Propellant Loading with Liquid Hydrogen
Muratov, Cyrill
when liquid hydrogen is moved from a storage tank to an external tank via a transfer line. By employingDynamical Model of Rocket Propellant Loading with Liquid Hydrogen Viatcheslav V. Osipov MCT, Incevaporation of hydrogen, pressurization of the tanks, and liquid hydrogen and hydrogen vaporflows inthe presence
Open problem: Dynamic Relational Models for Improved Hazardous Weather Prediction
McGovern, Amy
Open problem: Dynamic Relational Models for Improved Hazardous Weather Prediction Amy McGovern1 dis- covery methods for use on mesoscale weather data. Severe weather phenomena such as tornados, thun, current techniques for predicting severe weather are tied to specific characteristics of the radar systems
On the characteristics of aerosol indirect effect based on dynamic regimes in global climate models
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhang, S.; Wang, M.; Ghan, S. J.; Ding, A.; Wang, H.; Zhang, K.; Neubauer, D.; Lohmann, U.; Ferrachat, S.; Takeamura, T.; et al
2015-09-02
Aerosol-cloud interactions continue to constitute a major source of uncertainty for the estimate of climate radiative forcing. The variation of aerosol indirect effects (AIE) in climate models is investigated across different dynamical regimes, determined by monthly mean 500 hPa vertical pressure velocity (?500), lower-tropospheric stability (LTS) and large-scale surface precipitation rate derived from several global climate models (GCMs), with a focus on liquid water path (LWP) response to cloud condensation nuclei (CCN) concentrations. The LWP sensitivity to aerosol perturbation within dynamic regimes is found to exhibit a large spread among these GCMs. It is in regimes of strong large-scale ascendmore »(?500 ?1) and low clouds (stratocumulus and trade wind cumulus) where the models differ most. Shortwave aerosol indirect forcing is also found to differ significantly among different regimes. Shortwave aerosol indirect forcing in ascending regimes is as large as that in stratocumulus regimes, which indicates that regimes with strong large-scale ascend are as important as stratocumulus regimes in studying AIE. It is further shown that shortwave aerosol indirect forcing over regions with high monthly large-scale surface precipitation rate (> 0.1 mm d?1) contributes the most to the total aerosol indirect forcing (from 64 to nearly 100 %). Results show that the uncertainty in AIE is even larger within specific dynamical regimes than that globally, pointing to the need to reduce the uncertainty in AIE in different dynamical regimes.« less
Gauge turbulence, topological defect dynamics, and condensation in Higgs models
Gasenzer, Thomas; McLerran, Larry; Pawlowski, Jan M.; Sexty, Dénes
2014-07-28
The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.
Gauge turbulence, topological defect dynamics, and condensation in Higgs models
Gasenzer, Thomas [Heidelberg Univ. (Germany). Inst. for Theoretische Physik; GSI-Darmstadt (Germany). ExtreMe Matter Inst. (EMMI); McLerran, Larry [Brookhaven National Lab. (BNL), Upton, NY (United States). RIKEN Research Center and Physics Dept.; China Central Normal Univ., Wuhan (China). Physics Dept.; Pawlowski, Jan M. [Heidelberg Univ. (Germany). Inst. for Theoretische Physik; GSI-Darmstadt (Germany). ExtreMe Matter Inst. (EMMI); Sexty, Dénes [Heidelberg Univ. (Germany). Inst. for Theoretische Physik; GSI-Darmstadt (Germany). ExtreMe Matter Inst. (EMMI)
2014-10-01
The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.
Gauge turbulence, topological defect dynamics, and condensation in Higgs models
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gasenzer, Thomas; McLerran, Larry; Pawlowski, Jan M.; Sexty, Dénes
2014-07-28
The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixedmore »point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.« less
On the modelling of spur and helical gear dynamic behaviour
Velex, Philippe
2012-01-01
This chapter is aimed at introducing the fundamentals of spur and helical gear dynamics. Using three-dimensional lumped models and a thin-slice approach for mesh elasticity, the general equations of motion for single-stage spur or helical gears are presented. Some particular cases including the classic one degree-of-freedom model are examined in order to introduce and illustrate the basic phenomena. The interest of the concept of transmission errors is analysed and a number of practical considerations are deduced. Emphasis is deliberately placed on analytical results which, although approximate, allow a clearer understanding of gear dynamics than that provided by extensive numerical simulations. Some extensions towards continuous models are presented.
Mathematical Modeling of Microbial Community Dynamics: A Methodological Review
Song, Hyun-Seob; Cannon, William R.; Beliaev, Alex S.; Konopka, Allan
2014-10-17
Microorganisms in nature form diverse communities that dynamically change in structure and function in response to environmental variations. As a complex adaptive system, microbial communities show higher-order properties that are not present in individual microbes, but arise from their interactions. Predictive mathematical models not only help to understand the underlying principles of the dynamics and emergent properties of natural and synthetic microbial communities, but also provide key knowledge required for engineering them. In this article, we provide an overview of mathematical tools that include not only current mainstream approaches, but also less traditional approaches that, in our opinion, can be potentially useful. We discuss a broad range of methods ranging from low-resolution supra-organismal to high-resolution individual-based modeling. Particularly, we highlight the integrative approaches that synergistically combine disparate methods. In conclusion, we provide our outlook for the key aspects that should be further developed to move microbial community modeling towards greater predictive power.
Gaussian Process Model for Collision Dynamics of Complex Molecules
Cui, Jie
2015-01-01
We show that a Gaussian Process model can be combined with a small number of scattering calculations to provide an accurate multi-dimensional dependence of scattering observables on the experimentally controllable parameters (such as the collision energy, temperature or external fields) as well as the potential energy surface parameters. This can be used for solving the inverse scattering problem, the prediction of collision properties of a specific molecular system based on the information for another molecule, the efficient calculation of thermally averaged observables and for reducing the error of the molecular dynamics calculations by averaging over the potential energy surface variations. We show that, trained by a combination of classical and quantum dynamics calculations, the model provides an accurate description of the scattering cross sections, even near scattering resonances. In this case, the classical calculations stabilize the model against uncertainties arising from wildly varying correlations ...
Sensitivity analysis of a dynamic model for submerged arc silicon furnaces.
Foss, Bjarne A.
Sensitivity analysis of a dynamic model for submerged arc silicon furnaces. B. F. Lund1 , B. A for a dynamic model of submerged arc silicon furnaces. The model we study, called "Simod", was developed updating a nonlinear, dynamic model of a silicon furnace. We have identified a parameter set that has
Model for dynamic self-assembled magnetic surface structures.
Belkin, M.; Glatz, A.; Snezhko, A.; Aranson, I. S.; Materials Science Division; Northwestern Univ.
2010-07-07
We propose a first-principles model for the dynamic self-assembly of magnetic structures at a water-air interface reported in earlier experiments. The model is based on the Navier-Stokes equation for liquids in shallow water approximation coupled to Newton equations for interacting magnetic particles suspended at a water-air interface. The model reproduces most of the observed phenomenology, including spontaneous formation of magnetic snakelike structures, generation of large-scale vortex flows, complex ferromagnetic-antiferromagnetic ordering of the snake, and self-propulsion of bead-snake hybrids.
MODELLING GROUNDWATER FLOW ON THE REGIONAL SCALE IN THE UPPER DANUBE CATCHMENT (GERMANY)
Cirpka, Olaf Arie
MODELLING GROUNDWATER FLOW ON THE REGIONAL SCALE IN THE UPPER DANUBE CATCHMENT (GERMANY) Roland.barthel@iws.uni-stuttgart.de Abstract. A groundwater flow model for the Upper Danube catchment (A=77,000km2 at gauge Passau, Germany coupled models. Modelling of groundwater flow, using coupled deterministic and hydrological approaches
Regional forecasting with global atmospheric models; Third year report
Crowley, T.J.; North, G.R.; Smith, N.R.
1994-05-01
This report was prepared by the Applied Research Corporation (ARC), College Station, Texas, under subcontract to Pacific Northwest Laboratory (PNL) as part of a global climate studies task. The task supports site characterization work required for the selection of a potential high-level nuclear waste repository and is part of the Performance Assessment Scientific Support (PASS) Program at PNL. The work is under the overall direction of the Office of Civilian Radioactive Waste Management (OCRWM), US Department of Energy Headquarters, Washington, DC. The scope of the report is to present the results of the third year`s work on the atmospheric modeling part of the global climate studies task. The development testing of computer models and initial results are discussed. The appendices contain several studies that provide supporting information and guidance to the modeling work and further details on computer model development. Complete documentation of the models, including user information, will be prepared under separate reports and manuals.
Modeling optical and UV polarization of AGNs III. From uniform-density to clumpy regions
Marin, F; Gaskell, C M
2015-01-01
A growing body of evidence suggests that part of, if not all, scattering regions of active galactic nuclei (AGNs) are clumpy. Hence. in this paper, we run radiative transfer models in the optical/UV for a variety of AGN reprocessing regions with different distributions of clumpy scattering media. We use the latest version of the Monte Carlo code STOKES presented in the first two papers of this series to model AGN reprocessing regions of increasing morphological complexity. We replace previously uniform-density media with up to thousands of constant-density clumps. We couple a continuum source to fragmented equatorial scattering regions, polar outflows, and toroidal, obscuring dust regions and investigate a wide range of geometries. We also consider different levels of fragmentation in each scattering region to evaluate importance of fragmentation for the net polarization of the AGN. We find that, in comparison with uniform-density models, equatorial distributions of gas and dust clouds result in grayer spectr...
2015-01-01
a new regional earth system model to inform natural andsystems, coupled earth system models (EaSMs) are essential.coupled regional earth system models (EaSMs). Decision
Ritschard, R.L.
2010-01-01
comprehensive list of model and data base assumptions and toe.g. , scenario, data base, model linkages, etc. , andfor regional models (largely due to data base constraints).
Annual Report On Regional Aquifer Modeling And Data Analysis
Lu, Zhiming
.................................................................................. 13 3.1 Estimates based on 2-D flow, measured hydraulic gradients and field-based hydraulic........................................................................... 19 4.2 Model Calibrations, Using New Water Level Data from R-wells
Johnston, Robert A.; Gao, Shengyi; Clay, Michael J.
2008-01-01
Barra. Comparison from the Sacramento Model Testbed. Transp.Management Policies in the Sacramento Region: Year Two.Land Use Scenarios for the Sacramento Region, Using Citizen-
Model of a deterministic detector and dynamical decoherence
Lee, Jae Weon; Shepelyansky, Dima L. [Laboratoire de Physique Theorique, UMR 5152 du CNRS, Univ. P. Sabatier, 31062 Toulouse Cedex 4 (France); Averin, Dmitri V. [Department of Physics, University of Stony Brook, SUNY, Stony Brook, New York 11794 (United States); Benenti, Giuliano [Center for Nonlinear and Complex Systems, Universita degli Studi dell'Insubria and Istituto Nazionale per la Fisica della Materia, Unita di Como, Via Valleggio 11, 22100 Como (Italy)
2005-07-15
We discuss a deterministic model of detector coupled to a two-level system (a qubit). The detector is a quasiclassical object whose dynamics is described by the kicked rotator Hamiltonian. We show that in the regime of quantum chaos the detector acts as a chaotic bath and induces decoherence of the qubit. We discuss the dephasing and relaxation rates and demonstrate that the main features of single-qubit decoherence due to a heat bath can be reproduced by our fully deterministic dynamical model. Moreover, we show that, for strong enough qubit-detector coupling, the dephasing rate is given by the rate of exponential instability of the detector's dynamics, that is, by the Lyapunov exponent of classical motion. Finally, we discuss the measurement in the regimes of strong and weak qubit-detector coupling. For the case of strong coupling the detector performs a measurement of the up/down state of the qubit. In the case of weak coupling, due to chaos, the dynamical evolution of the detector is strongly sensitive to the state of the qubit. However, in this case it is unclear how to extract a signal from any measurement with a coarse-graining in the phase space on a size much larger than the Planck cell.
Multi-resolution modeling of the dynamic loading of metal matrix...
Office of Scientific and Technical Information (OSTI)
Multi-resolution modeling of the dynamic loading of metal matrix composites. Citation Details In-Document Search Title: Multi-resolution modeling of the dynamic loading of metal...
Dynamic ModelingDynamic Modeling the Electric Power Networkthe Electric Power Network
Oro, Daniel
at the National Energy Modeling System/Annual Energy Outlook Conference, Washington, DC, March 10, 2003] #12
On preparation of viscous pore fluids for dynamic centrifuge modelling
Adamidis, O.; Madabhushi, S. P. G.
2014-11-21
upon cooling. Gelation temperatures for METHOCEL F50 are well above the expected range of temperatures in dynamic centrifuge modelling [Dow, 2002]. As a result, the gelation process is not consid- ered in this study. Measurements of viscosity... + e e · ki (24) where k is the coefficient of permeability and i is the hydraulic gradient. Since an upper estimate for shearing rate is sought after, the critical hydraulic gradient, for which the seepage forces become equal to the submerged weight...
Drowsy Region-Based Caches: Minimizing Both Dynamic and Static Power Dissipation
McKee, Sally A.
increasingly greater die area. Among dynamic power conservation schemes, horizontal partitioning reduces reductions in the cache system of up to 68-71%, depending on memory configuration, with a small increase for reducing leakage is drowsy caching [3], a memory design that exploits dynamic voltage scaling: reduced
Nuclear Hybrid Energy System Modeling: RELAP5 Dynamic Coupling Capabilities
Piyush Sabharwall; Nolan Anderson; Haihua Zhao; Shannon Bragg-Sitton; George Mesina
2012-09-01
The nuclear hybrid energy systems (NHES) research team is currently developing a dynamic simulation of an integrated hybrid energy system. A detailed simulation of proposed NHES architectures will allow initial computational demonstration of a tightly coupled NHES to identify key reactor subsystem requirements, identify candidate reactor technologies for a hybrid system, and identify key challenges to operation of the coupled system. This work will provide a baseline for later coupling of design-specific reactor models through industry collaboration. The modeling capability addressed in this report focuses on the reactor subsystem simulation.
CREATING DYNAMIC EQUIVALENT PV CIRCUIT MODELS WITH IMPEDANCE SPECTROSCOPY FOR ARC FAULT MODELING
CREATING DYNAMIC EQUIVALENT PV CIRCUIT MODELS WITH IMPEDANCE SPECTROSCOPY FOR ARC FAULT MODELING ® (NEC® ) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc of the arcing frequencies through PV components despite the potential for modules and other PV components
Modelling the e#ects of air pollution on health using Bayesian Dynamic Generalised Linear Models
Bath, University of
(2004)). Large multicity studies such as `Air pollution and health: a European approach' (APHEA across a number of US and European cities. Shortterm e#ects of air pollution on health are estimatedModelling the e#ects of air pollution on health using Bayesian Dynamic Generalised Linear Models
Modeling Needs Related to the Regional Observing System in the Gulf of Maine
Modeling Needs Related to the Regional Observing System in the Gulf of Maine RARGOM Report 05-1 Theme Session 6-7 July, 2005 Cliff House Ogunquit, Maine Convened by Regional Association for Research on the Gulf of Maine Gulf of Maine Census of Marine Life Gulf of Maine Ocean Observing System Coastal
Go to the Right of the Pillar: Modeling Unoccupied Regions for Robot Directives
Skubic, Marjorie
Go to the Right of the Pillar: Modeling Unoccupied Regions for Robot Directives Marjorie Skubic and Sam Blisard Dept. of Computer Engineering and Computer Science University of Missouri of regions that do not contain objects but may be referenced by objects in the environment, to compute target
User Guide for PV Dynamic Model Simulation Written on PSCAD Platform
Muljadi, E.; Singh, M.; Gevorgian, V.
2014-11-01
This document describes the dynamic photovoltaic model developed by the National Renewable Energy Laboratory and is intended as a guide for users of these models.
Use dynamic simulation to model HPU reactor depressuring
Ernest, J.B.; Depew, C.A. (Fluor Daniel, Inc., Irvine, CA (United States))
1995-01-01
Dynamic simulation is the best available method for the analysis of hydroprocessing unit (HPU) depressuring. Depressuring is crucial for the safe operation of hydrocracking and other HPUs with catalysts that have hydrocracking activity. Effective design for depressuring is valuable for all types of HPUs, both grass-roots and revamps. Reactor loop depressuring can set design temperatures and pressures for the reactor effluent cooling train and other equipment and piping in an HPU. Unfortunately, usual methods for determining equipment and piping design conditions during depressuring leave much room for improvement because they poorly account for time-dependent temperature and pressure changes. Dynamic simulation makes it practical to more accurately estimate these transient conditions. The paper discusses depressuring design, including the nature of depressuring, the impact of depressuring on design, and depressuring calculation methods. The author then describes modeling of hydroprocessing unit depressuring by discussing the general and particular correspondence of simulation modules to physical equipment using the base case of total electrical power failure. The special data that is required for dynamic simulation is described and typical simulation results are given. Lastly, the advantages of dynamic simulation are summarized.
Dynamics of Molecular Motors in Reversible Burnt-Bridge Models
Maxim N. Artyomov; Alexander Yu. Morozov; Anatoly B. Kolomeisky
2009-11-22
Dynamic properties of molecular motors whose motion is powered by interactions with specific lattice bonds are studied theoretically with the help of discrete-state stochastic "burnt-bridge" models. Molecular motors are depicted as random walkers that can destroy or rebuild periodically distributed weak connections ("bridges") when crossing them, with probabilities $p_1$ and $p_2$ correspondingly. Dynamic properties, such as velocities and dispersions, are obtained in exact and explicit form for arbitrary values of parameters $p_1$ and $p_2$. For the unbiased random walker, reversible burning of the bridges results in a biased directed motion with a dynamic transition observed at very small concentrations of bridges. In the case of backward biased molecular motor its backward velocity is reduced and a reversal of the direction of motion is observed for some range of parameters. It is also found that the dispersion demonstrates a complex, non-monotonic behavior with large fluctuations for some set of parameters. Complex dynamics of the system is discussed by analyzing the behavior of the molecular motors near burned bridges.
Modeling Regional Air Quality Using the Near-Explicit Master Chemical Mechanism
Li, Jingyi
2014-08-01
structure, allowing an explicit calculation of SOA formation from individual model species. Earlier attempts in this area were aimed at developing mechanisms for regional SOA using a small number of representative species (Griffin et al., 2002b; Griffin...
Humbert, Mark Edward
1980-01-01
MESOSCALE ENVIRONMENTAL MODELS ACCOMPANYING CONVECTION IN THE TEXAS HIPLEX REGION A Thesis by MARK EDWARD HUMBERT Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE May 1980 Major Subject: Meteorology MESOSCALE ENVIRONMENTAL MODELS ACCOMPANYING CONVECTION IN THE TEXAS HIPLEX REGION A Thesis by MARK EDWARD HUMBERT Approved as to style and content by: (Chairman of Co ttee) (Head of Department) (Member...
Eulerian hydrocode modeling of a dynamic tensile extrusion experiment (u)
Burkett, Michael W; Clancy, Sean P
2009-01-01
Eulerian hydrocode simulations utilizing the Mechanical Threshold Stress flow stress model were performed to provide insight into a dynamic extrusion experiment. The dynamic extrusion response of copper (three different grain sizes) and tantalum spheres were simulated with MESA, an explicit, 2-D Eulerian continuum mechanics hydrocode and compared with experimental data. The experimental data consisted of high-speed images of the extrusion process, recovered extruded samples, and post test metallography. The hydrocode was developed to predict large-strain and high-strain-rate loading problems. Some of the features of the features of MESA include a high-order advection algorithm, a material interface tracking scheme and a van Leer monotonic advection-limiting. The Mechanical Threshold Stress (MTS) model was utilized to evolve the flow stress as a function of strain, strain rate and temperature for copper and tantalum. Plastic strains exceeding 300% were predicted in the extrusion of copper at 400 m/s, while plastic strains exceeding 800% were predicted for Ta. Quantitative comparisons between the predicted and measured deformation topologies and extrusion rate were made. Additionally, predictions of the texture evolution (based upon the deformation rate history and the rigid body rotations experienced by the copper during the extrusion process) were compared with the orientation imaging microscopy measurements. Finally, comparisons between the calculated and measured influence of the initial texture on the dynamic extrusion response of tantalum was performed.
Dynamic mesoscale model of dipolar fluids via fluctuating hydrodynamics
Persson, Rasmus A. X.; Chu, Jhih-Wei, E-mail: jwchu@nctu.edu.tw [Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu 30068, Taiwan (China); Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30068, Taiwan (China); Voulgarakis, Nikolaos K. [Department of Mathematics, Washington State University, Richland, Washington 99372 (United States)
2014-11-07
Fluctuating hydrodynamics (FHD) is a general framework of mesoscopic modeling and simulation based on conservational laws and constitutive equations of linear and nonlinear responses. However, explicit representation of electrical forces in FHD has yet to appear. In this work, we devised an Ansatz for the dynamics of dipole moment densities that is linked with the Poisson equation of the electrical potential ? in coupling to the other equations of FHD. The resulting ?-FHD equations then serve as a platform for integrating the essential forces, including electrostatics in addition to hydrodynamics, pressure-volume equation of state, surface tension, and solvent-particle interactions that govern the emergent behaviors of molecular systems at an intermediate scale. This unique merit of ?-FHD is illustrated by showing that the water dielectric function and ion hydration free energies in homogeneous and heterogenous systems can be captured accurately via the mesoscopic simulation. Furthermore, we show that the field variables of ?-FHD can be mapped from the trajectory of an all-atom molecular dynamics simulation such that model development and parametrization can be based on the information obtained at a finer-grained scale. With the aforementioned multiscale capabilities and a spatial resolution as high as 5 Ĺ, the ?-FHD equations represent a useful semi-explicit solvent model for the modeling and simulation of complex systems, such as biomolecular machines and nanofluidics.
Multiphase flow in the advanced fluid dynamics model
Bohl, W.R.; Wilhelm, D.; Berthier, J.; Parker, F.P.; Ichikawa, S.; Goutagny, L.; Ninokata, H.
1988-01-01
This paper describes the modeling used in the Advanced Fluid Dynamics Model (AFDM), a computer code to investigate new approaches to simulating severe accidents in fast reactors. The AFDM code has 12 topologies describing what material contacts are possible depending on the presence or absence of a given material in a computational cell, the dominant liquid, and the continuous phase. Single-phase, bubbly, churn-turbulent, cellular, and dispersed flow are permitted for the pool situations modeled. Interfacial areas between the continuous and discontinuous phases are convected to allow some tracking of phenomenological histories. Interfacial areas also are modified by models of nucleation, dynamic forces, turbulence, flashing, coalescence, and mass transfer. Heat transfer generally is treated using engineering correlations. Liquid/vapor phase transitions are handled with a nonequililbrium heat-transfer-limited model, whereas melting and freezing processes are based on equilibrium considerations. The Los Alamos SESAME equation of state (EOS) has been inplemented using densities and temperatures as the independent variables. A summary description of the AFDM numerical algorithm is provided. The AFDM code currently is being debugged and checked out. Two sample three-field calculations also are presented. The first is a three-phase bubble column mixing experiment performed at Argonne National Laboratory; the second is a liquid-liquid mixing experiment performed at Kernforschungszentrum, Karlsruhe, that resulted in rapid vapor production. We conclude that only qualitative comparisons currently are possible for complex multiphase situations. Many further model developments can be pursued, but there are limits because of the lack of a comprehensive theory, the lack of detailed multicomponent experimental data, and the difficulties in keeping the resulting model complexities tractable.
Computational fluid dynamic modeling of fluidized-bed polymerization reactors
Rokkam, Ram
2012-11-02
Polyethylene is one of the most widely used plastics, and over 60 million tons are produced worldwide every year. Polyethylene is obtained by the catalytic polymerization of ethylene in gas and liquid phase reactors. The gas phase processes are more advantageous, and use fluidized-bed reactors for production of polyethylene. Since they operate so close to the melting point of the polymer, agglomeration is an operational concern in all slurry and gas polymerization processes. Electrostatics and hot spot formation are the main factors that contribute to agglomeration in gas-phase processes. Electrostatic charges in gas phase polymerization fluidized bed reactors are known to influence the bed hydrodynamics, particle elutriation, bubble size, bubble shape etc. Accumulation of electrostatic charges in the fluidized-bed can lead to operational issues. In this work a first-principles electrostatic model is developed and coupled with a multi-fluid computational fluid dynamic (CFD) model to understand the effect of electrostatics on the dynamics of a fluidized-bed. The multi-fluid CFD model for gas-particle flow is based on the kinetic theory of granular flows closures. The electrostatic model is developed based on a fixed, size-dependent charge for each type of particle (catalyst, polymer, polymer fines) phase. The combined CFD model is first verified using simple test cases, validated with experiments and applied to a pilot-scale polymerization fluidized-bed reactor. The CFD model reproduced qualitative trends in particle segregation and entrainment due to electrostatic charges observed in experiments. For the scale up of fluidized bed reactor, filtered models are developed and implemented on pilot scale reactor.
Broader source: Energy.gov [DOE]
In this report, we introduce a new transparent regional capacity expansion model with high spatio-temporal resolution and detailed representation of dispatch. The development of this model, referred to as the Resource Planning Model (RPM), is motivated by the lack of a tool in the public domain that can be used to characterize optimal regional deployment of resources with detailed dispatch modeling. In particular, RPM is designed to evaluate scenarios of renewable technology deployment to meet renewable portfolio standard (RPS) and emission-reduction goals, and to project possible deployment levels for various projections of future technology and fuel prices.
Mai, T.; Drury, E.; Eurek, K.; Bodington, N.; Lopez, A.; Perry, A.
2013-01-01
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.
Alternating-phase focusing: A model to study nonlinear dynamics
Sagalovsky, L.; Delayen, J.R.
1992-01-01
We discuss a new model to study alternating-phase focusing (APF). Our approach is based on representing the accelerating electric field with a continuous phase modulated traveling wave. The resulting nonlinear equations of motion can be solved analytically to predict the regions of stable APF motion. We also identify the key parameters which adequately describe the physics of APF. The model is believed to be applicable to low-{beta} ion linacs with short independently-controlled superconducting cavities being developed at ANL.
Alternating-phase focusing: A model to study nonlinear dynamics
Sagalovsky, L.; Delayen, J.R.
1992-09-01
We discuss a new model to study alternating-phase focusing (APF). Our approach is based on representing the accelerating electric field with a continuous phase modulated traveling wave. The resulting nonlinear equations of motion can be solved analytically to predict the regions of stable APF motion. We also identify the key parameters which adequately describe the physics of APF. The model is believed to be applicable to low-{beta} ion linacs with short independently-controlled superconducting cavities being developed at ANL.
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.
2008-08-01
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.
Model for Aggregated Water Heater Load Using Dynamic Bayesian Networks
Vlachopoulou, Maria; Chin, George; Fuller, Jason C.; Lu, Shuai; Kalsi, Karanjit
2012-07-19
The transition to the new generation power grid, or “smart grid”, requires novel ways of using and analyzing data collected from the grid infrastructure. Fundamental functionalities like demand response (DR), that the smart grid needs, rely heavily on the ability of the energy providers and distributors to forecast the load behavior of appliances under different DR strategies. This paper presents a new model of aggregated water heater load, based on dynamic Bayesian networks (DBNs). The model has been validated against simulated data from an open source distribution simulation software (GridLAB-D). The results presented in this paper demonstrate that the DBN model accurately tracks the load profile curves of aggregated water heaters under different testing scenarios.
Dynamic Decision Making for Graphical Models Applied to Oil Exploration
Martinelli, Gabriele; Hauge, Ragnar
2012-01-01
We present a framework for sequential decision making in problems described by graphical models. The setting is given by dependent discrete random variables with associated costs or revenues. In our examples, the dependent variables are the potential outcomes (oil, gas or dry) when drilling a petroleum well. The goal is to develop an optimal selection strategy that incorporates a chosen utility function within an approximated dynamic programming scheme. We propose and compare different approximations, from simple heuristics to more complex iterative schemes, and we discuss their computational properties. We apply our strategies to oil exploration over multiple prospects modeled by a directed acyclic graph, and to a reservoir drilling decision problem modeled by a Markov random field. The results show that the suggested strategies clearly improve the simpler intuitive constructions, and this is useful when selecting exploration policies.
Integrated Canada-U.S. Power Sector Modeling with the Regional Energy Deployment System (ReEDS)
Martinez, A.; Eurek, K.; Mai, T.; Perry, A.
2013-02-01
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.
Jiang, Chaowei; Feng, Xueshang [SIGMA Weather Group, State Key Laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Wu, S. T.; Hu, Qiang, E-mail: cwjiang@spaceweather.ac.cn, E-mail: fengx@spaceweather.ac.cn, E-mail: wus@uah.edu, E-mail: qh0001@uah.edu [Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL 35899 (United States)
2014-01-01
We present a comprehensive study of the formation and eruption of an active region (AR) sigmoid in AR 11283. To follow the quasi-static evolution of the coronal magnetic field, we reconstruct a time sequence of static fields using a recently developed nonlinear force-free field model constrained by vector magnetograms. A detailed analysis of the fields compared with observations suggests the following scenario for the evolution of the region. Initially, a new bipole emerges into the negative polarity of a preexisting bipolar AR, forming a null-point topology between the two flux systems. A weakly twisted flux rope (FR) is then built up slowly in the embedded core region, largely through flux cancellation, forming a bald patch separatrix surface (BPSS). The FR grows gradually until its axis runs into a torus instability (TI) domain, and the BPSS also develops a full S-shape. The combined effects of the TI-driven expansion of the FR and the line tying at the BP tear the FR into two parts with the upper portion freely expelled and the lower portion remaining behind the postflare arcades. This process dynamically perturbs the BPSS and results in the enhanced heating of the sigmoid and the rope. The accelerated expansion of the upper-portion rope strongly pushes its envelope flux near the null point and triggers breakout reconnection at the null, which further drives the eruption. We discuss the important implications of these results for the formation and disruption of the sigmoid region with an FR.
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, ...
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, ...
Gutowski, William J.; Prusa, Joseph M.; Smolarkiewicz, Piotr K.
2012-05-08
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
Entanglement dynamics in a model tripartite quantum system
Pradip Laha; B. Sudarsan; S. Lakshmibala; V. Balakrishnan
2015-09-23
A system comprising a $\\Lambda$-type or V-type atom interacting with two radiation fields exhibits, during its dynamical evolution, interesting optical phenomena such as electromagnetically-induced transparency (EIT) and a variety of nonclassical effects. Signatures of the latter are seen in the entanglement dynamics of the atomic subsystem and in appropriate field observables. Some of these effects have been experimentally detected, and have even been used to change the nonlinear optical properties of certain atomic media. It is therefore useful to investigate the roles played by specific initial states of the radiation fields, detuning parameters, field nonlinearities and the nature of field-atom couplings on EIT and on the entanglement between subsystems. We investigate these aspects in the framework of a simple model that captures the salient features of such tripartite entangled systems. Entanglement dynamics is shown to be very sensitive to the intensity-dependent atom-field couplings. Unexpected interesting features pertaining to the collapses and revivals of the atomic subsystem von Neumann entropy appear. These features could, in principle, be useful in enabling entanglement.
Dynamic Properties of Molecular Motors in Burnt-Bridge Models
Maxim N. Artyomov; Alexander Yu. Morozov; Ekaterina Pronina; Anatoly B. Kolomeisky
2007-05-04
Dynamic properties of molecular motors that fuel their motion by actively interacting with underlying molecular tracks are studied theoretically via discrete-state stochastic ``burnt-bridge'' models. The transport of the particles is viewed as an effective diffusion along one-dimensional lattices with periodically distributed weak links. When an unbiased random walker passes the weak link it can be destroyed (``burned'') with probability p, providing a bias in the motion of the molecular motor. A new theoretical approach that allows one to calculate exactly all dynamic properties of motor proteins, such as velocity and dispersion, at general conditions is presented. It is found that dispersion is a decreasing function of the concentration of bridges, while the dependence of dispersion on the burning probability is more complex. Our calculations also show a gap in dispersion for very low concentrations of weak links which indicates a dynamic phase transition between unbiased and biased diffusion regimes. Theoretical findings are supported by Monte Carlo computer simulations.
A LUMPED-PARAMETER DYNAMIC MODEL OF A THERMAL REGENERATOR FOR FREE-PISTON STIRLING ENGINES
Barth, Eric J.
A LUMPED-PARAMETER DYNAMIC MODEL OF A THERMAL REGENERATOR FOR FREE-PISTON STIRLING ENGINES Mark the mass flow, piston dynamics, and control volume behavior inside a free-piston Stirling engine. A new model for a Stirling engine thermal regenerator that incorporates a dynamically changing temperature
Polymer dynamics in repton model at large fields Anatoly B. Kolomeisky
Polymer dynamics in repton model at large fields Anatoly B. Kolomeisky Department of Chemistry, Poland Received 22 October 2003; accepted 26 January 2004 Polymer dynamics at large fields in Rubinstein simple exclusion models are used to analyze the reptation dynamics of polymers. It is found
Temporal Models for Groundwater Level Prediction in Regions of Maharashtra Dissertation Report
Sohoni, Milind
Temporal Models for Groundwater Level Prediction in Regions of Maharashtra Dissertation Report In this project work we perform analysis of groundwater level data in three districts of Maha- rashtra - Thane of these districts and developed seasonal models to represent the groundwater be- havior. Three different type
Coupling of Integrated Biosphere Simulator to Regional Climate Model version 3
Winter, Jonathan (Jonathan Mark)
2006-01-01
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, ...
An improved model of the lightning electromagnetic field interaction with the D-region ionosphere
14 March 2012. [1] We present an improved time-domain model of the lightning electromagnetic pulse. Introduction [2] Lightning discharges produce both an electromagnetic pulse (EMP), due to the rapid lightningAn improved model of the lightning electromagnetic field interaction with the D-region ionosphere R
Abundance determinations in HII regions: model fitting versus Te-method
L. S. Pilyugin
2002-11-14
The discrepancy between the oxygen abundances in high-metallicity HII regions determined through the Te-method (and/or through the corresponding "strong lines - oxygen abundance" calibration) and that determined through the model fitting (and/or through the corresponding "strong lines - oxygen abundance" calibration) is discussed. It is suggested to use the interstellar oxygen abundance in the solar vicinity, derived with very high precision from the high-resolution observations of the weak interstellar absorption lines towards the stars, as a "Rosetta stone" to verify the validity of the oxygen abundances derived in HII regions with the Te-method at high abundances. The agreement between the value of the oxygen abundance at the solar galactocentric distance traced by the abundances derived in HII regions through the Te-method and that derived from the interstellar absorption lines towards the stars is strong evidence in favor of that i) the two-zone model for Te seems to be a realistic interpretation of the temperature structure within HII regions, and ii) the classic Te-method provides accurate oxygen abundances in HII regions. It has been concluded that the "strong lines - oxygen abundance" calibrations must be based on the HII regions with the oxygen abundances derived with the Te-method but not on the existing grids of the models for HII regions.
A Dynamic Supply-Demand Model for Electricity Prices Manuela Buzoianu
A Dynamic Supply-Demand Model for Electricity Prices Manuela Buzoianu , Anthony E. Brockwell to as a dynamic supply-demand model, to simultaneously capture electricity price and usage time series. This model, and Duane J. Seppi Abstract We introduce a new model for electricity prices, based on the principle
Designability, thermodynamic stability, and dynamics in protein folding: A lattice model study
Levine, Alex J.
Designability, thermodynamic stability, and dynamics in protein folding: A lattice model study Re October 1998 In the framework of a lattice-model study of protein folding, we investigate the interplay model. Lattice models have been widely used in the study of protein folding dynamics.28 The main
Statistical Models for Solar Flare Interval Distribution in Individual Active Regions
Yuki Kubo
2008-02-01
This article discusses statistical models for solar flare interval distribution in individual active regions. We analyzed solar flare data in 55 active regions that are listed in the GOES soft X-ray flare catalog. We discuss some problems with a conventional procedure to derive probability density functions from any data set and propose a new procedure, which uses the maximum likelihood method and Akaike Information Criterion (AIC) to objectively compare some competing probability density functions. We found that lognormal and inverse Gaussian models are more likely models than the exponential model for solar flare interval distribution in individual active regions. The results suggest that solar flares do not occur randomly in time; rather, solar flare intervals appear to be regulated by solar flare mechanisms. We briefly mention a probabilistic solar flare forecasting method as an application of a solar flare interval distribution analysis.
Weeks, Eric R.
this behavior. The mode coupling theory [1] describes many aspects of dynamical behavior at high T is not only relevant in spin models [26], but also in a viscous equilibrium liquid. Finally, we show is still the understanding of the tremen- dous slowing down of molecular dynamics in supercooled liquids
Modeling Temporal Behavior in Large Networks: A Dynamic Mixed-Membership Model
Rossi, R; Gallagher, B; Neville, J; Henderson, K
2011-11-11
Given a large time-evolving network, how can we model and characterize the temporal behaviors of individual nodes (and network states)? How can we model the behavioral transition patterns of nodes? We propose a temporal behavior model that captures the 'roles' of nodes in the graph and how they evolve over time. The proposed dynamic behavioral mixed-membership model (DBMM) is scalable, fully automatic (no user-defined parameters), non-parametric/data-driven (no specific functional form or parameterization), interpretable (identifies explainable patterns), and flexible (applicable to dynamic and streaming networks). Moreover, the interpretable behavioral roles are generalizable, computationally efficient, and natively supports attributes. We applied our model for (a) identifying patterns and trends of nodes and network states based on the temporal behavior, (b) predicting future structural changes, and (c) detecting unusual temporal behavior transitions. We use eight large real-world datasets from different time-evolving settings (dynamic and streaming). In particular, we model the evolving mixed-memberships and the corresponding behavioral transitions of Twitter, Facebook, IP-Traces, Email (University), Internet AS, Enron, Reality, and IMDB. The experiments demonstrate the scalability, flexibility, and effectiveness of our model for identifying interesting patterns, detecting unusual structural transitions, and predicting the future structural changes of the network and individual nodes.
Entanglement dynamics for the double Tavis-Cummings model
Zhong-Xiao Man; Yun-Jie Xia; Nguyen Ba An
2009-02-14
A double Tavis-Cummings model (DTCM) is developed to simulate the entanglement dynamics of realistic quantum information processing where two entangled atom-pairs $AB$ and $CD$ are distributed in such a way that atoms $AC$ are embedded in a cavity $a$ while $BD$ are located in another remote cavity $b$. The evolutions of different types of initially shared entanglement of atoms are studied under various initial states of cavity fields. The results obtained in the DTCM are compared with that obtained in the double Jaynes-Cummings model (DJCM) [J. Phys. B \\textbf{40}, S45 (2007)] and an interaction strength theory is proposed to explain the parameter domain in which the so-called entanglement sudden death occurs for both the DTCM and DJCM.
Griffith, Daniel Todd
2005-02-17
The main objective of this work is to demonstrate some new computational methods for estimation, optimization and modeling of dynamical systems that use automatic differentiation. Particular focus will be upon dynamical ...
Detonating Failed Deflagration Model of Thermonuclear Supernovae I. Explosion Dynamics
Tomasz Plewa
2006-11-24
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)
2012-01-01
Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO{sub 2} concentration. To account for this known variability in nitrogen-photosynthesis relationships, we develop a mechanistic nitrogen allocation model based on a trade-off of nitrogen allocated between growth and storage, and an optimization of nitrogen allocated among light capture, electron transport, carboxylation, and respiration. The developed model is able to predict the acclimation of photosynthetic capacity to changes in CO{sub 2} concentration, temperature, and radiation when evaluated against published data of V{sub c,max} (maximum carboxylation rate) and J{sub max} (maximum electron transport rate). A sensitivity analysis of the model for herbaceous plants, deciduous and evergreen trees implies that elevated CO{sub 2} concentrations lead to lower allocation of nitrogen to carboxylation but higher allocation to storage. Higher growing-season temperatures cause lower allocation of nitrogen to carboxylation, due to higher nitrogen requirements for light capture pigments and for storage. Lower levels of radiation have a much stronger effect on allocation of nitrogen to carboxylation for herbaceous plants than for trees, resulting from higher nitrogen requirements for light capture for herbaceous plants. As far as we know, this is the first model of complete nitrogen allocation that simultaneously considers nitrogen allocation to light capture, electron transport, carboxylation, respiration and storage, and the responses of each to altered environmental conditions. We expect this model could potentially improve our confidence in simulations of carbon-nitrogen interactions and the vegetation feedbacks to climate in Earth system models.
Parameter Estimation of Dynamic Air-conditioning Component Models Using Limited Sensor Data
Hariharan, Natarajkumar
2011-08-08
This thesis presents an approach for identifying critical model parameters in dynamic air-conditioning systems using limited sensor information. The expansion valve model and the compressor model parameters play a crucial ...
DYNAMIC MODELLING OF LIVING ANIONIC SOLUTION POLYMERIZATION OF STYRENE/BUTADIENE/DIVINYLBENZENE
Schittkowski, Klaus
DYNAMIC MODELLING OF LIVING ANIONIC SOLUTION POLYMERIZATION OF STYRENE/BUTADIENE model for the living anionic solution polymerization of styrene/butadiene/divinylbenzene in a continuous kinetic reactor model for the living anionic solution polymerization of styrene/butadiene
VISION -- A Dynamic Model of the Nuclear Fuel Cycle
J. J. Jacobson; A. M. Yacout; S. J. Piet; D. E. Shropshire; G. E. Matthern
2006-02-01
The Advanced Fuel Cycle Initiative’s (AFCI) fundamental objective is to provide technology options that – if implemented – would enable long-term growth of nuclear power while improving sustainability and energy security. The AFCI organization structure consists of four areas; Systems Analysis, Fuels, Separations and Transmutations. The Systems Analysis Working Group is tasked with bridging the program technical areas and providing the models, tools, and analyses required to assess the feasibility of design and deploy¬ment options and inform key decision makers. An integral part of the Systems Analysis tool set is the development of a system level model that can be used to examine the implications of the different mixes of reactors, implications of fuel reprocessing, impact of deployment technologies, as well as potential “exit” or “off ramp” approaches to phase out technologies, waste management issues and long-term repository needs. The Verifiable Fuel Cycle Simulation Model (VISION) is a computer-based simulation model that allows performing dynamic simulations of fuel cycles to quantify infrastructure requirements and identify key trade-offs between alternatives. VISION is intended to serve as a broad systems analysis and study tool applicable to work conducted as part of the AFCI (including costs estimates) and Generation IV reactor development studies.
Castro, Christopher L.
to observations. The Great Plains low-level jet (LLJ) is also well represented in both RAMS and NARR, but the Baja Atmospheric Modeling System (RAMS). Part I: Model Climatology (19502002) CHRISTOPHER L. CASTRO* Department downscaled using the Regional Atmospheric Modeling System (RAMS) to generate a regional climate model (RCM
Huang, Hsin-Yuan; Hall, Alex
2013-07-24
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.
THE DYNAMICAL STRUCTURE FACTOR AND CRITICAL BEHAVIOR OF A TRAFFIC FLOW MODEL
Lübeck, Sven
261 THE DYNAMICAL STRUCTURE FACTOR AND CRITICAL BEHAVIOR OF A TRAFFIC FLOW MODEL L. ROTERS, S. L. The behavior of the model is determined by three parameters, the maximal velocity v max , the noise parameter P of the dynamical structure factor of the Nagel Schreckenberg traffic flow model based on the local occupation
2015-01-01
systems, coupled earth system models (EaSMs) are essential.a new regional earth system model to inform natural andthe Community Earth System Model (CESM; www2.cesm.ucar.edu)
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.
2012-03-21
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.
Comparing the escape dynamics in tidally limited star cluster models
Euaggelos E. Zotos
2015-08-21
The aim of this work is to compare the orbital dynamics in three different models describing the properties of a star cluster rotating around its parent galaxy in a circular orbit. In particular, we use the isochrone and the Hernquist potentials to model the spherically symmetric star cluster and we compare our results with the corresponding ones of a previous work in which the Plummer model was applied for the same purpose. Our analysis takes place both in the configuration $(x,y)$ and in the phase $(x,\\dot{x})$ space in order to elucidate the escape process as well as the overall orbital properties of the tidally limited star cluster. We restrict our investigation into two dimensions and we conduct a thorough numerical analysis distinguishing between ordered and chaotic orbits as well as between trapped and escaping orbits, considering only unbounded motion for several energy levels above the critical escape energy. It is of particular interest to determine the escape basins towards the two exit channels (near the Lagrangian points $L_1$ and $L_2$) and relate them with the corresponding escape times of the orbits.
Comparing the escape dynamics in tidally limited star cluster models
Zotos, Euaggelos E
2015-01-01
The aim of this work is to compare the orbital dynamics in three different models describing the properties of a star cluster rotating around its parent galaxy in a circular orbit. In particular, we use the isochrone and the Hernquist potentials to model the spherically symmetric star cluster and we compare our results with the corresponding ones of a previous work in which the Plummer model was applied for the same purpose. Our analysis takes place both in the configuration $(x,y)$ and in the phase $(x,\\dot{x})$ space in order to elucidate the escape process as well as the overall orbital properties of the tidally limited star cluster. We restrict our investigation into two dimensions and we conduct a thorough numerical analysis distinguishing between ordered and chaotic orbits as well as between trapped and escaping orbits, considering only unbounded motion for several energy levels above the critical escape energy. It is of particular interest to determine the escape basins towards the two exit channels (n...
Description of waste pretreatment and interfacing systems dynamic simulation model
Garbrick, D.J.; Zimmerman, B.D.
1995-05-01
The Waste Pretreatment and Interfacing Systems Dynamic Simulation Model was created to investigate the required pretreatment facility processing rates for both high level and low level waste so that the vitrification of tank waste can be completed according to the milestones defined in the Tri-Party Agreement (TPA). In order to achieve this objective, the processes upstream and downstream of the pretreatment facilities must also be included. The simulation model starts with retrieval of tank waste and ends with vitrification for both low level and high level wastes. This report describes the results of three simulation cases: one based on suggested average facility processing rates, one with facility rates determined so that approximately 6 new DSTs are required, and one with facility rates determined so that approximately no new DSTs are required. It appears, based on the simulation results, that reasonable facility processing rates can be selected so that no new DSTs are required by the TWRS program. However, this conclusion must be viewed with respect to the modeling assumptions, described in detail in the report. Also included in the report, in an appendix, are results of two sensitivity cases: one with glass plant water recycle steams recycled versus not recycled, and one employing the TPA SST retrieval schedule versus a more uniform SST retrieval schedule. Both recycling and retrieval schedule appear to have a significant impact on overall tank usage.
Temperature dependent transport coefficients in a dynamical holographic QCD model
Danning Li; Song He; Mei Huang
2014-11-19
We investigate temperature dependent behavior of various transport coefficients in a dynamical holographical QCD model. We show the nontrivial temperature dependent behavior of the transport coefficients, like bulk viscosity, electric conductivity as well as jet quenching parameter, and it is found that all these quantities reveal information of the phase transition. Furthermore, with introducing higher derivative corrections in 5D gravity, the shear viscosity over entropy density ratio also shows a valley around phase transition, and it is found that the shear viscosity over entropy density ratio times the jet quenching over temperature cubic ratio almost remains as a constant above phase transition, and the value is two times larger than the perturbative result in Phys.Rev.Lett.99.192301(2007).
Hydro-dynamical models for the chaotic dripping faucet
P. Coullet; L. Mahadevan; C. S. Riera
2004-08-20
We give a hydrodynamical explanation for the chaotic behaviour of a dripping faucet using the results of the stability analysis of a static pendant drop and a proper orthogonal decomposition (POD) of the complete dynamics. We find that the only relevant modes are the two classical normal forms associated with a Saddle-Node-Andronov bifurcation and a Shilnikov homoclinic bifurcation. This allows us to construct a hierarchy of reduced order models including maps and ordinary differential equations which are able to qualitatively explain prior experiments and numerical simulations of the governing partial differential equations and provide an explanation for the complexity in dripping. We also provide a new mechanical analogue for the dripping faucet and a simple rationale for the transition from dripping to jetting modes in the flow from a faucet.
Hydro-dynamical models for the chaotic dripping faucet
Coullet, P; Riera, C S
2004-01-01
We give a hydrodynamical explanation for the chaotic behaviour of a dripping faucet using the results of the stability analysis of a static pendant drop and a proper orthogonal decomposition (POD) of the complete dynamics. We find that the only relevant modes are the two classical normal forms associated with a Saddle-Node-Andronov bifurcation and a Shilnikov homoclinic bifurcation. This allows us to construct a hierarchy of reduced order models including maps and ordinary differential equations which are able to qualitatively explain prior experiments and numerical simulations of the governing partial differential equations and provide an explanation for the complexity in dripping. We also provide a new mechanical analogue for the dripping faucet and a simple rationale for the transition from dripping to jetting modes in the flow from a faucet.
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 ...
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
2014-12-01
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.
Emerging disease dynamics in a model coupling within-host and ...
Xiuli Cen
2014-08-27
Aug 2, 2014 ... Immunological models consider the within-host dynamics independent of the interactions between hosts (e.g., De Leenheer and Smith, 2003;.
Microscale and mesoscale discrete models for dynamic fracture of structures built of brittle are derived either at microscale with random distribution of material properties or at a mesoscale
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
2011-06-01
Article 690.11 in the 2011 National Electrical Code{reg_sign} (NEC{reg_sign}) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc fault protection device. Currently there is little experimental or empirical research into the behavior of the arcing frequencies through PV components despite the potential for modules and other PV components to filter or attenuate arcing signatures that could render the arc detector ineffective. To model AC arcing signal propagation along PV strings, the well-studied DC diode models were found to inadequately capture the behavior of high frequency arcing signals. Instead dynamic equivalent circuit models of PV modules were required to describe the impedance for alternating currents in modules. The nonlinearities present in PV cells resulting from irradiance, temperature, frequency, and bias voltage variations make modeling these systems challenging. Linearized dynamic equivalent circuits were created for multiple PV module manufacturers and module technologies. The equivalent resistances and capacitances for the modules were determined using impedance spectroscopy with no bias voltage and no irradiance. The equivalent circuit model was employed to evaluate modules having irradiance conditions that could not be measured directly with the instrumentation. Although there was a wide range of circuit component values, the complex impedance model does not predict filtering of arc fault frequencies in PV strings for any irradiance level. Experimental results with no irradiance agree with the model and show nearly no attenuation for 1 Hz to 100 kHz input frequencies.
High-resolution observations of active region moss and its dynamics
Morton, R J
2014-01-01
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...
Boyer, Edmond
, and simple models are usually considered in the analysis. This is an important constraint when uncertaintiesProbabilistic model identification of the bit-rock-interaction-model uncertainties in nonlinear model of uncertainties in a bit-rock interaction model for the nonlinear dynamics of a drill
Mixtures of Predictive Linear Gaussian Models for Nonlinear Stochastic Dynamical Systems
Baveja, Satinder Singh
Mixtures of Predictive Linear Gaussian Models for Nonlinear Stochastic Dynamical Systems David dynamical systems. The primary contribution of this work is to extend the PLG to nonlinear, stochastic- proves upon traditional linear dynamical system mod- els by using a predictive representation of state
Implementation of an Urban Parameterization Scheme into the Regional Climate Model COSMO-CLM
July 2012, in final form 23 April 2013) ABSTRACT As the nonhydrostatic regional model of the Consortium of urbanization on the environment, the authors extend its surface-layer parameterization by the Town Energy on spatial scales below ;3 km. 1. Introduction Since the level of world urbanization crossed the 50% mark
A MODIFIED GAMBLER'S RUIN MODEL POLYETHYLENE CHAINS IN THE AMORPHOUS REGION
A MODIFIED GAMBLER'S RUIN MODEL OF POLYETHYLENE CHAINS IN THE AMORPHOUS REGION ZhongHui 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
Fowler, Hayley
further demonstrates that existing precautionary allowances for climate change used for flood managementClick Here for Full Article Detecting changes in seasonal precipitation extremes using regional climate model projections: Implications for managing fluvial flood risk H. J. Fowler1 and R. L. Wilby2
Menut, Laurent
the a priori uncertainties in anthropogenic NOx and volatile organic compounds (VOC) emissions: (1) The a posteriori probability density function (pdf) for NOx emissions is not modified in its averageBayesian Monte Carlo analysis applied to regional-scale inverse emission modeling for reactive
Huppert, Herbert
Static and flowing regions in granular collapses down channels: Insights from a sedimenting shallow extend the model of Larrieu 2006 to include an estimation for the interface between the static, 043301 2007 . An empirical sedimentation term Ls and the instantaneous removal of a static deposit wedge
Spatial variability of regional model simulated JuneSeptember mean precipitation over West Africa
made with the CCSR/GISS RM3, driven by synchronous data from NCEP reanalysis. A five-member ensemble for a single season was generated by staggering the initial conditions of each member by 36 hr within] Regional climate model (RCM) simulations are driven by synchronous lateral boundary conditions (LBC
A Prototype Integrated Transportation Land-use Model for the Lausanne Region
Bierlaire, Michel
of Architecture, Civil and Environmental Engineering Ecole Polytechnique F´ed´erale de Lausanne transp . . . . . . . . . . . . . . . . . . . . . 6 3.2 Demographic Transition Model . . . . . . . . . . . . . . . . . . . 6 3.3 Development Project-Morges Region in 2000 . . . . . . . . . . . . . . . 14 6 UrbanSim Submodels Estimated for the Lausanne-Morges Re
Polar-region distributions of Poynting flux: Global models compared with observations
Lotko, William
of electric potential, field-aligned current and Poynting flux derived from the Lyon-Fedder-Mobarry globalPolar-region distributions of Poynting flux: Global models compared with observations P. D submitted to J. Atmospheric and Solar-Terrestrial Physics 15 June 2007 #12;with updated simulation results
Polar-region distributions of Poynting flux: Global models compared with observations
Lotko, William
of electric potential, field-aligned current and Poynting flux derived from the Lyon-Fedder-Mobarry globalPolar-region distributions of Poynting flux: Global models compared with observations P. D from the Preprint submitted to J. Atmospheric and Solar-Terrestrial Physics 11 July 2008 #12;DMSP F13
A Dynamic Solar Core model: the SSM-like solution
Attila Grandpierre
1998-08-31
I point out that the all the arguments against an astrophysical solution do not exclude a yet not recognised class of solar models, in which an explosive energy source is present in the solar core besides the standard pp and CNO cycle. It is shown from first principle physics that stars have a non-pp,CNO source: local thermonuclear runaways. I derive a model independent inequality, which shows that the problem of the missing beryllium neutrinos lies in that the SuperKamiokande contains a term arising from neutrinos from a runaway source which can produce high-energy electrons and high-energy axions, and muon and tau neutrinos. I point out, that the temperature dependence of the individual neutrino fluxes is related to pure nuclear physics but the usual luminosity constraint is model dependent and actually is a questionable assumption. Allowing non-pp,CNO reaction chains a new approach arises to interpret the neutrino detector data. The explicit temperature dependence leads to $\\Phi_{pp} \\propto T^4$ instead of the usual $\\Phi_{pp} \\propto T^{-1/2}$ for the SSM luminosity constraint. I assume a Sun analogue to the SSM with a different $T_c$. The separate neutrino detector equations lead to separate detector-related temperatures with the neutrino detector data. The results show a slightly lower than standard central temperature. I attempt to show that helioseismology is not in a necessary conflict with the dynamic solar model presented here. The results of the calculations may propose solutions to the problems of solar and atmospheric neutrino oscillations without an ad hoc introduction of sterile neutrinos and present predictions to Borexino and SNO measurements. {\\it PACS numbers}: 26.65+t, 26.30.+k, 96.60Jw, 95.30.Cq
THE NONPOTENTIALITY OF ACTIVE-REGION CORONAE AND THE DYNAMICS OF THE PHOTOSPHERIC MAGNETIC FIELD
Schrijver, Karel
The magnetic field in the solar photosphere frequently carries strong electric currents, even though the global that the global coronal magnetic field is often largely potential, provided that high-current systems induced by the pressure of the solar wind plasma are allowed for. The most commonly used model, the potential-field source
A Dynamic Solar Core Model: the Deviant Temperatures Approach
Attila Grandpierre
1998-08-31
I derive here a model independent inequality which shows that the problem of the missing beryllium neutrinos of the Sun roots in the fact that the SuperKamiokande contains a term arising from a non-pp,CNO source. First principle physics shows that the non-pp,CNO source is of thermonuclear runaway origin. Several indications suggest that the non-pp,CNO term plays a more significant role in the solar neutrino problems than neutrino oscillations. When removing the over-restricted SSM luminosity constraint, the temperature dependence of the neutrino fluxes is related to pure nuclear physics and follows $\\Phi_{pp} \\propto T^4$ instead of $\\Phi_{pp} \\propto T^{-1/2}$. The results of the calculations offer solutions to the solar neutrino problems and problems of neutrino oscillations. The dynamic solar model presents predictions to Borexino and SNO measurements. These predictions can serve to distinguish between the MSW and the non-pp,CNO effect. {\\it PACS numbers|: 26.65.+t, 26.30.+k, 96.60.JW, 95.30.Cq
Kimbell, J.S.; Gross, E.A.; Joyner, D.R.; Godo, M.N.; Morgan, K.T. (Chemical Industry Institute of Toxicology, Research Triangle Park, NC (United States))
1993-08-01
For certain inhaled air pollutants, such as reactive, water soluble gases, the distribution of nasal lesions observed in F344 rats may be closely related to regional gas uptake patterns in the nose. These uptake patterns can be influenced by the currents of air flowing through the upper respiratory tract during the breathing cycle. Since data on respiratory tract lesions in F344 rats are extrapolated to humans to make predictions of risk to human health, a better understanding of the factors affecting these responses is needed. To assess potential effects of nasal airflow on lesion location and severity, a methodology was developed for creation of computer simulations of steady-state airflow and gas transport using a three-dimensional finite element grid reconstructed from serial step-sections of the nasal passages of a male F344 rat. Simulations on a supercomputer used the computational fluid dynamics package FIDAP (FDI, Evanston, IL). Distinct streams of bulk flow evident in the simulations matched inspiratory streams reported for the F344 rat. Moreover, simulated regional flow velocities matched measured velocities in concurrent laboratory experiments with a hollow nasal mold. Computer-predicted flows were used in simulations of gas transport to nasal passage walls, with formaldehyde as a test case. Results from the uptake simulations were compared with the reported distribution of formaldehyde-induced nasal lesions observed in the F344 rat, and indicated that airflow-driven uptake patterns probably play an important role in determining the location of certain nasal lesions induced by formaldehyde. This work demonstrated the feasibility of applying computational fluid dynamics to airflow-driven dosimetry of inhaled chemicals in the upper respiratory tract.
Ultrafast Structural Dynamics in Combustion Relevant Model Systems
Weber, Peter M.
2014-03-31
The research project explored the time resolved structural dynamics of important model reaction system using an array of novel methods that were developed specifically for this purpose. They include time resolved electron diffraction, time resolved relativistic electron diffraction, and time resolved Rydberg fingerprint spectroscopy. Toward the end of the funding period, we also developed time-resolved x-ray diffraction, which uses ultrafast x-ray pulses at LCLS. Those experiments are just now blossoming, as the funding period expired. In the following, the time resolved Rydberg Fingerprint Spectroscopy is discussed in some detail, as it has been a very productive method. The binding energy of an electron in a Rydberg state, that is, the energy difference between the Rydberg level and the ground state of the molecular ion, has been found to be a uniquely powerful tool to characterize the molecular structure. To rationalize the structure sensitivity we invoke a picture from electron diffraction: when it passes the molecular ion core, the Rydberg electron experiences a phase shift compared to an electron in a hydrogen atom. This phase shift requires an adjustment of the binding energy of the electron, which is measurable. As in electron diffraction, the phase shift depends on the molecular, geometrical structure, so that a measurement of the electron binding energy can be interpreted as a measurement of the molecule’s structure. Building on this insight, we have developed a structurally sensitive spectroscopy: the molecule is first elevated to the Rydberg state, and the binding energy is then measured using photoelectron spectroscopy. The molecule’s structure is read out as the binding energy spectrum. Since the photoionization can be done with ultrafast laser pulses, the technique is inherently capable of a time resolution in the femtosecond regime. For the purpose of identifying the structures of molecules during chemical reactions, and for the analysis of molecular species in the hot environments of combustion processes, there are several features that make the Rydberg ionization spectroscopy uniquely useful. First, the Rydberg electron’s orbit is quite large and covers the entire molecule for most molecular structures of combustion interest. Secondly, the ionization does not change vibrational quantum numbers, so that even complicated and large molecules can be observed with fairly well resolved spectra. In fact, the spectroscopy is blind to vibrational excitation of the molecule. This has the interesting consequence for the study of chemical dynamics, where the molecules are invariably very energetic, that the molecular structures are observed unobstructed by the vibrational congestion that dominates other spectroscopies. This implies also that, as a tool to probe the time-dependent structural dynamics of chemically interesting molecules, Rydberg spectroscopy may well be better suited than electron or x-ray diffraction. With recent progress in calculating Rydberg binding energy spectra, we are approaching the point where the method can be evolved into a structure determination method. To implement the Rydberg ionization spectroscopy we use a molecular beam based, time-resolved pump-probe multi-photon ionization/photoelectron scheme in which a first laser pulse excites the molecule to a Rydberg state, and a probe pulse ionizes the molecule. A time-of-flight detector measures the kinetic energy spectrum of the photoelectrons. The photoelectron spectrum directly provides the binding energy of the electron, and thereby reveals the molecule’s time-dependent structural fingerprint. Only the duration of the laser pulses limits the time resolution. With a new laser system, we have now reached time resolutions better than 100 fs, although very deep UV wavelengths (down to 190 nm) have slightly longer instrument functions. The structural dynamics of molecules in Rydberg-excited states is obtained by delaying the probe ionization photon from the pump photon; the structural dynamics of molecules in their ground state or e
Stochastic model for aerodynamic force dynamics on wind turbine blades in unsteady wind inflow
Luhur, Muhammad Ramzan; Kühn, Martin; Wächter, Matthias
2015-01-01
The paper presents a stochastic approach to estimate the aerodynamic forces with local dynamics on wind turbine blades in unsteady wind inflow. This is done by integrating a stochastic model of lift and drag dynamics for an airfoil into the aerodynamic simulation software AeroDyn. The model is added as an alternative to the static table lookup approach in blade element momentum (BEM) wake model used by AeroDyn. The stochastic forces are obtained for a rotor blade element using full field turbulence simulated wind data input and compared with the classical BEM and dynamic stall models for identical conditions. The comparison shows that the stochastic model generates additional extended dynamic response in terms of local force fluctuations. Further, the comparison of statistics between the classical BEM, dynamic stall and stochastic models' results in terms of their increment probability density functions gives consistent results.
Toriumi, Shin; Cheung, Mark C M
2015-01-01
Light bridges, the bright structures that divide the umbra of sunspots and pores into smaller pieces, are known to produce wide variety of activity events in solar active regions (ARs). It is also known that the light bridges appear in the assembling process of nascent sunspots. The ultimate goal of this series of papers is to reveal the nature of light bridges in developing ARs and the occurrence of activity events associated with the light bridge structures from both observational and numerical approaches. In this first paper, exploiting the observational data obtained by Hinode, IRIS, and Solar Dynamics Observatory (SDO), we investigate the detailed structure of the light bridge in NOAA AR 11974 and its dynamic activity phenomena. As a result, we find that the light bridge has a weak, horizontal magnetic field, which is transported from the interior by large-scale convective upflow and is surrounded by strong, vertical fields of adjacent pores. In the chromosphere above the bridge, a transient brightening ...
Wetland model in an earth systems modeling framework for regional environmental policy analysis
Awadalla, Sirein Salah
2011-01-01
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 ...
AIR INGRESS ANALYSIS: PART 2 – COMPUTATIONAL FLUID DYNAMIC MODELS
Chang H. Oh; Eung S. Kim; Richard Schultz; Hans Gougar; David Petti; Hyung S. Kang
2011-01-01
The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena Identification and Ranking Studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the in-the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of the lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to the release of fission products into the confinement, which could be detrimental to a reactor safety. Computational fluid dynamic model developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional and three-dimensional CFD results for the quantitative assessment of the air ingress phenomena. A portion of results of the density-driven stratified flow in the inlet pipe will be compared with results of the experimental results.
REGIONAL SEISMIC AMPLITUDE MODELING AND TOMOGRAPHY FOR EARTHQUAKE-EXPLOSION DISCRIMINATION
Walter, W R; Pasyanos, M E; Matzel, E; Gok, R; Sweeney, J; Ford, S R; Rodgers, A J
2008-07-08
We continue exploring methodologies to improve earthquake-explosion discrimination using regional amplitude ratios such as P/S in a variety of frequency bands. Empirically we demonstrate that such ratios separate explosions from earthquakes using closely located pairs of earthquakes and explosions recorded on common, publicly available stations at test sites around the world (e.g. Nevada, Novaya Zemlya, Semipalatinsk, Lop Nor, India, Pakistan, and North Korea). We are also examining if there is any relationship between the observed P/S and the point source variability revealed by longer period full waveform modeling (e. g. Ford et al 2008). For example, regional waveform modeling shows strong tectonic release from the May 1998 India test, in contrast with very little tectonic release in the October 2006 North Korea test, but the P/S discrimination behavior appears similar in both events using the limited regional data available. While regional amplitude ratios such as P/S can separate events in close proximity, it is also empirically well known that path effects can greatly distort observed amplitudes and make earthquakes appear very explosion-like. Previously we have shown that the MDAC (Magnitude Distance Amplitude Correction, Walter and Taylor, 2001) technique can account for simple 1-D attenuation and geometrical spreading corrections, as well as magnitude and site effects. However in some regions 1-D path corrections are a poor approximation and we need to develop 2-D path corrections. Here we demonstrate a new 2-D attenuation tomography technique using the MDAC earthquake source model applied to a set of events and stations in both the Middle East and the Yellow Sea Korean Peninsula regions. We believe this new 2-D MDAC tomography has the potential to greatly improve earthquake-explosion discrimination, particularly in tectonically complex regions such as the Middle East. Monitoring the world for potential nuclear explosions requires characterizing seismic events and discriminating between natural and man-made seismic events, such as earthquakes and mining activities, and nuclear weapons testing. We continue developing, testing, and refining size-, distance-, and location-based regional seismic amplitude corrections to facilitate the comparison of all events that are recorded at a particular seismic station. These corrections, calibrated for each station, reduce amplitude measurement scatter and improve discrimination performance. We test the methods on well-known (ground truth) datasets in the U.S. and then apply them to the uncalibrated stations in Eurasia, Africa, and other regions of interest to improve underground nuclear test monitoring capability.
DYNAMIC MODELING AND CONTROL OF REACTIVE DISTILLATION FOR HYDROGENATION OF BENZENE
Aluko, Obanifemi
2010-01-16
This work presents a modeling and control study of a reactive distillation column used for hydrogenation of benzene. A steady state and a dynamic model have been developed to investigate control structures for the column. ...
Modelling of power plant dynamics and uncertainties for robust control synthesis *
Ray, Asok
, TRAC type models3 have been applied to perform safety analysis of nuclear power plants. However, complex dynamic processes such as fossil and nuclear power plants can be modelled and simulated
Networking technology adoption : system dynamics modeling of fiber-to-the-home
Kelic, Andjelka, 1972-
2005-01-01
A system dynamics model is developed and run to study the adoption of fiber-to-the-home as a residential broadband technology. Communities that currently do not have broadband in the United States are modeled. This case ...
Data-based Subsystem Identification for Dynamic Model Updating Steven Gillijns and Bart De Moor
Data-based Subsystem Identification for Dynamic Model Updating Steven Gillijns and Bart De Moor-pump example. I. INTRODUCTION Models induced from physical laws and models identified from data are both values. In empirical models, inaccuracies can be due to an inappropriate model class or to bad data
Borders as membranes :metaphors and models for improved policy in border regions.
Malczynski, Leonard A.; Passell, Howard David; Forster, Craig B. (University of Utah, Salt Lake City, UT); Cockerill, Kristan (Cockerill Consulting, Boone, NC)
2005-10-01
Political borders are controversial and contested spaces. In an attempt to better understand movement along and through political borders, this project applied the metaphor of a membrane to look at how people, ideas, and things ''move'' through a border. More specifically, the research team employed this metaphor in a system dynamics framework to construct a computer model to assess legal and illegal migration on the US-Mexico border. Employing a metaphor can be helpful, as it was in this project, to gain different perspectives on a complex system. In addition to the metaphor, the multidisciplinary team utilized an array of methods to gather data including traditional literature searches, an experts workshop, a focus group, interviews, and culling expertise from the individuals on the research team. Results from the qualitative efforts revealed strong social as well as economic drivers that motivate individuals to cross the border legally. Based on the information gathered, the team concluded that legal migration dynamics were of a scope we did not want to consider hence, available demographic models sufficiently capture migration at the local level. Results from both the quantitative and qualitative data searches were used to modify a 1977 border model to demonstrate the dynamic nature of illegal migration. Model runs reveal that current US-policies based on neo-classic economic theory have proven ineffective in curbing illegal migration, and that proposed enforcement policies are also likely to be ineffective. We suggest, based on model results, that improvement in economic conditions within Mexico may have the biggest impact on illegal migration to the U.S. The modeling also supports the views expressed in the current literature suggesting that demographic and economic changes within Mexico are likely to slow illegal migration by 2060 with no special interventions made by either government.
Modeling dynamic crack propagation in fiber reinforced composites including frictional effects q
Espinosa, Horacio D.
Modeling dynamic crack propagation in fiber reinforced composites including frictional effects q S Abstract Dynamic crack propagation in a unidirectional carbon/epoxy composite is studied through finite deformation anisotropic visco-plastic model is used to describe the constitutive response of the composite
DATA COLLECTION FOR DEVELOPING A DYNAMIC MODEL OF A LIGHT HELICOPTER
DATA COLLECTION FOR DEVELOPING A DYNAMIC MODEL OF A LIGHT HELICOPTER Stefano Geluardi 1,2 , Frank for Biological Cybernetics the influence of an augmented system on helicopter pilots with limited flight skills are necessary to identify the helicopter dynamic model. The mathematical and technical tools used to reach
Modelling Desert Dune Fields Based on Discrete Dynamics STEVEN R. BISHOPa,
Carretero, Ricardo
Modelling Desert Dune Fields Based on Discrete Dynamics STEVEN R. BISHOPa, *, HIROSHI MOMIJIb is developed to model the dynamics of sand dunes. The physical processes display strong non-linearity that has features we monitor morphology, dune growth, dune migration and spatial patterns within a dune field
Dang, Zhe
Bond Computing Systems: a Biologically Inspired and High-level Dynamics Model for Pervasive. Targeting at modeling the high-level dynamics of pervasive comput- ing systems, we introduce Bond Computing are regular, and study their computation power and verification problems. Among other results, we show
Xu, Haiping
that DRBD provides a powerful tool for system reliability modeling, and our proposed verification approachFORMAL SEMANTICS AND VERIFICATION OF DYNAMIC RELIABILITY BLOCK DIAGRAMS FOR SYSTEM RELIABILITY-scale computer-based systems. KEY WORDS Reliability modeling, dynamic reliability block diagrams (DRBD), Object
Berning, Torsten
Aalborg Universitet Dynamic Modeling of a Reformed Methanol Fuel Cell System using Empirical Data Reza Published in: Journal of Fuel Cell Science and Technology DOI (link to publication from Publisher. K., Andreasen, S. J., & Shaker, H. R. (2014). Dynamic Modeling of a Reformed Methanol Fuel Cell
GLOBAL STABILITY FOR A VIRUS DYNAMICS MODEL WITH NONLINEAR INCIDENCE OF INFECTION AND REMOVAL
GLOBAL STABILITY FOR A VIRUS DYNAMICS MODEL WITH NONLINEAR INCIDENCE OF INFECTION AND REMOVAL PAUL GEORGESCU AND YING-HEN HSIEH Abstract. Global dynamics of a compartmental model which describes virus and the removal rate of the virus are assumed to be nonlinear. In the case where the functional quotient between
Nagurney, Anna
An Efficiency Measure for Dynamic Networks Modeled as Evolutionary Variational Inequalities propose an efficiency/performance measure for dynamic net- works, which have been modeled as evolutionary and their rankings. We provide both continuous time and discrete time versions of the efficiency measure. We
Multi-Point Contact Models for Dynamic Self-Righting of a Hexapod
Multi-Point Contact Models for Dynamic Self-Righting of a Hexapod Uluc. Saranli1 , Alfred A. Rizzi1 on the design of a model-based controller that can achieve dynamical self-righting of a hexapod robot. Extending hexapod robot that negotiates badly irregular terrain at speeds better than one body length per second [12
Understanding Collective Crowd Behaviors: Learning a Mixture Model of Dynamic Pedestrian-Agents
Wang, Xiaogang
Understanding Collective Crowd Behaviors: Learning a Mixture Model of Dynamic Pedestrian@ee.cuhk.edu.hk, xtang@ie.cuhk.edu.hk Abstract In this paper, a new Mixture model of Dynamic pedestrian-Agents (MDA) is proposed to learn the collective behavior patterns of pedestrians in crowded scenes. Col- lective behaviors
Agarwal, Pratul K.
2015-11-24
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.
Agarwal, Pratul K.
2013-04-09
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.
Coupled thermodynamic-dynamic semi-analytical model of Free Piston Stirling engines
Formosa, Fabien
2013-01-01
The study of free piston Stirling engine (FPSE) requires both accurate thermodynamic and dynamic modelling to predict its performances. The steady state behaviour of the engine partly relies on non linear dissipative phenomena such as pressure drop loss within heat exchangers which is dependant on the temperature within the associated components. An analytical thermodynamic model which encompasses the effectiveness and the flaws of the heat exchangers and the regenerator has been previously developed and validated. A semi-analytical dynamic model of FPSE is developed and presented in this paper. The thermodynamic model is used to define the thermal variables that are used in the dynamic model which evaluates the kinematic results. Thus, a coupled iterative strategy has been used to perform a global simulation. The global modelling approach has been validated using the experimental data available from the NASA RE-1000 Stirling engine prototype. The resulting coupled thermodynamic-dynamic model using a standard...
Reports and Publications (EIA)
2010-01-01
The Regional Short-Term Energy Model (RSTEM) uses macroeconomic variables such as income, employment, industrial production and consumer prices at both the national and regional1 levels as explanatory variables in the generation of the Short-Term Energy Outlook (STEO). This documentation explains how national macroeconomic forecasts are used to update regional macroeconomic forecasts through the RSTEM Macro Bridge procedure.
Chen, Yuh-Ing
A study on the background and clustering seismicity in the Taiwan region by using point process), A study on the background and clustering seismicity in the Taiwan region by using point process models, J the shallow seismicity occurring in the Taiwan region during the 20th century using a stochastic declustering
McKenzie, Jeffrey M.
Analytical solutions for benchmarking cold regions subsurface water flow and energy transport Freezing and thawing a b s t r a c t Numerous cold regions water flow and energy transport models have of powerful simulators of cold regions subsurface water flow and energy transport have emerged in recent years
Yohe, G.W. )
1990-11-01
It is becoming increasingly clear, at least on a theoretical level, that modelers of the potential impacts of climate change must impose that change upon the world as it will be configured sometime in the future rather than confine their attention to considerations of what would happen to the world as it looks now. Initial baselines which focus on current circumstances are certainly worthwhile points of departure in any study, of course, but the truth is that social, economic, and political systems will evolve as the future unfolds; and careful analysis of that evolution across a globe experiencing changes in its climate must be undertaken, as well. In the vernacular of the analysts' workroom, while it may be interesting to try to see what would happen to dumb farmers'' who continue to do things as they always have regardless of what happens, it is critically important to evaluate the need for any sort of policy response to climate change in a world of smart farmers'' who will have observed the ramifications of climate change and responded in their own best interest. 9 refs., 2 figs.
Langner, Pawel
2009-11-26
Urban modelling and land-cover changes are well discussed in literature and are in a focal point of many researches. Regional urban growth (RUG) model for central Europe and the Baltic States projects land-cover changes ...
Global warming and climate change - predictive models for temperate and tropical regions
Malini, B.H.
1997-12-31
Based on the assumption of 4{degree}C increase of global temperature by the turn of 21st century due to the accumulation of greenhouse gases an attempt is made to study the possible variations in different climatic regimes. The predictive climatic water balance model for Hokkaido island of Japan (a temperate zone) indicates the possible occurrence of water deficit for two to three months, which is a unknown phenomenon in this region at present. Similarly, India which represents tropical region also will experience much drier climates with increased water deficit conditions. As a consequence, the thermal region of Hokkaido which at present is mostly Tundra and Micro thermal will change into a Meso thermal category. Similarly, the moisture regime which at present supports per humid (A2, A3 and A4) and Humid (B4) climates can support A1, B4, B3, B2 and B1 climates indicating a shift towards drier side of the climatic spectrum. Further, the predictive modes of both the regions have indicated increased evapotranspiration rates. Although there is not much of change in the overall thermal characteristics of the Indian region the moisture regime indicates a clear shift towards the aridity in the country.
Two-Way Integration of WRF and CCSM for Regional Climate Simulations...
Office of Scientific and Technical Information (OSTI)
the process of dynamical downscaling by avoiding massive intermediate model outputs at high frequency that are typically required for offline regional downscaling. The inline...
Phase transition free regions in the Ising model via the Kac-Ward operator
Marcin Lis
2015-05-17
We investigate the spectral radius and operator norm of the Kac-Ward transition matrix for the Ising model on a general planar graph. We then use the obtained results to identify regions in the complex plane where the free energy density limits are analytic functions of the inverse temperature. The bound turns out to be optimal in the case of isoradial graphs, i.e. it yields criticality of the self-dual Z-invariant coupling constants.
Mallet, Vivien
Inverse modeling of NOx emissions at regional scale over northern France: Preliminary investigation time distribution of NOx emissions is robust. Citation: Que´lo, D., V. Mallet, and B. Sportisse (2005), Inverse modeling of NOx emissions at regional scale over northern France: Preliminary investigation
Ren, Kui
On the modeling and simulation of reaction-transfer dynamics in semiconductor-electrolyte solar-performance semiconductor-liquid junction solar cells. We propose in this work a macroscopic mathematical model, a sys- tem-liquid junction, solar cell simulation, naso-scale device modeling. 1 Introduction The mathematical modeling
1 Abstract--Eventually, prediction of transformer thermal performance for dynamic loading will be made using models distilled from measure data, rather than models derived from transformer heat for measuring the acceptability of transformer thermal models. For a model to be acceptable, it must have
JACKSON VL
2011-08-31
The primary purpose of the tank mixing and sampling demonstration program is to mitigate the technical risks associated with the ability of the Hanford tank farm delivery and celtification systems to measure and deliver a uniformly mixed high-level waste (HLW) feed to the Waste Treatment and Immobilization Plant (WTP) Uniform feed to the WTP is a requirement of 24590-WTP-ICD-MG-01-019, ICD-19 - Interface Control Document for Waste Feed, although the exact definition of uniform is evolving in this context. Computational Fluid Dynamics (CFD) modeling has been used to assist in evaluating scaleup issues, study operational parameters, and predict mixing performance at full-scale.
Huntzinger, Deborah [University of Michigan; Post, Wilfred M [ORNL; Michalak, Anna [University of Michigan; West, Tristram O. [Joint Global Change Research Institute, PNNL; Jacobson, Andrew [NOAA ESRL and CIRES; Baker, Ian [Colorado State University, Fort Collins; Chen, Jing M. [University of Toronto; Davis, Kenneth [Pennsylvania State University; Hayes, Daniel J [ORNL; Hoffman, Forrest M [ORNL; Jain, Atul [University of Illinois, Urbana-Champaign; Liu, Shuguang [United States Geological Survey, Center for Earth Resources Observation and Science (USGS EROS); Mcguire, David [University of Alaska; Neilson, Ronald [Oregon State University, Corvallis; Poulter, Ben [Potsdam Institute for Climate Impact Research, Potsdam, Germany; Tian, Hanqin [Auburn University, Auburn, Alabama; Thornton, Peter E [ORNL; Tomelleri, Enrico [Max Planck Institute for Biogeochemistry; Viovy, Nicolas [National Center for Scientific Research, Gif-sur-Yvette, France; Xiao, Jingfeng [Purdue University; Cook, Robert B [ORNL
2012-01-01
Understanding of carbon exchange between terrestrial ecosystems and the atmosphere can be improved through direct observations and experiments, as well as through modeling activities. Terrestrial biosphere models (TBMs) have become an integral tool for extrapolating local observations and understanding to much larger terrestrial regions. Although models vary in their specific goals and approaches, their central role within carbon cycle science is to provide a better understanding of the mechanisms currently controlling carbon exchange. Recently, the North American Carbon Program (NACP) organized several interim-synthesis activities to evaluate and inter-compare models and observations at local to continental scales for the years 2000-2005. Here, we compare the results from the TBMs collected as part of the regional and continental interim-synthesis (RCIS) activities. The primary objective of this work is to synthesize and compare the 19 participating TBMs to assess current understanding of the terrestrial carbon cycle in North America. Thus, the RCIS focuses on model simulations available from analyses that have been completed by ongoing NACP projects and other recently published studies. The TBM flux estimates are compared and evaluated over different spatial (1{sup o} x 1{sup o} and spatially aggregated to different regions) and temporal (monthly and annually) scales. The range in model estimates of net ecosystem productivity (NEP) for North America is much narrower than estimates of productivity or respiration, with estimates of NEP varying between -0.7 and 2.2 PgC yr{sup -1}, while gross primary productivity and heterotrophic respiration vary between 12.2 and 32.9 PgC yr{sup -1} and 5.6 and 13.2 PgC yr{sup -1}, respectively. The range in estimates from the models appears to be driven by a combination of factors, including the representation of photosynthesis, the source and of environmental driver data and the temporal variability of those data, as well as whether nutrient limitation is considered in soil carbon decomposition. The disagreement in current estimates of carbon flux across North America, including whether North America is a net biospheric carbon source or sink, highlights the need for further analysis through the use of model runs following a common simulation protocol, in order to isolate the influences of model formulation, structure, and assumptions on flux estimates.
Markakis, Michail
This paper presents the results of a computational study that compares simulated compartmental (differential equation) and Volterra models of the dynamic effects of insulin on blood glucose concentration in humans. In the ...
Be Migration Studies at JET and their Interpretation by an Integrated Model for Plasma Impurity Transport and Wall Composition Dynamics
Hollow cathode theory and experiment. II. A two-dimensional theoretical model of the emitter region
Mikellides, Ioannis G.; Katz, Ira; Goebel, Dan M.; Polk, James E.
2005-12-01
Despite their long history and wide range of applicability that includes electric propulsion, detailed understanding of the driving physics inside orificed hollow cathodes remains elusive. The theoretical complexity associated with the multicomponent fluid inside the cathode, and the difficulty of accessing empirically this region, have limited our ability to design cathodes that perform better and last longer. A two-dimensional axisymmetric theoretical model of the multispecies fluid inside an orificed hollow cathode is presented. The level of detail attained by the model is allowed by its extended system of governing equations not solved for in the past within the hollow cathode. Such detail is motivated in part by the need to quantify the effect(s) of the plasma on the emitter life, and by the need to build the foundation for future modeling that will assess erosion of the keeper plate. Results from numerical simulations of a 1.2-cm-diam cathode operating at a discharge current of 25 A and a gas flow rate of 5 SCCM show that approximately 10 A of electron current, and 3.45 A of ion current return back to the emitter surface. The total emitted electron current is 33.8 A and the peak emitter temperature is found to be 1440 K. Comparisons with the measurements suggest that anomalous heating of the plasma is possible near the orifice region. The model predicts heavy species temperatures as high as 2034 K and peak voltage drops near the emitting surface not exceeding 8 V.
Zhang, Ming; Letiner, Thomas K; Korber, Bette T; Foley, Brian
2009-01-01
We have reexamined the subtype designations of {approx}10,000 subtype A, B, C, G, and AG, BC, BF recombinant sequences, and compared the results of the new analysis with their published designations. Intersubtype recombinants dominate HIV epidemics in three different geographical regions. The circulating recombinant from (CRF) CRF02-AG, common in West Central Africa, appears to result from a recombination event that occurred early in the divergence between subtypes A and G, although additional more recent recombination events may have contributed to the breakpoint pattern in this recombinant lineage as well. The Chinese recombinant epidemic strains CRF07 and CRF08, in contrast, result from recent recombinations between more contemporary strains. Nevertheless, CRF07 and CRF08 contributed to many subsequent recombination events. The BF recombinant epidemics in two HIV-1 epicenters in South America are not independent and BF epidemics in South America have an unusually high fraction of unique recombinant forms (URFs) that have each been found only once and carry distinctive breakpoints. Taken together, these analyses reveal a complex and dynamic picture of the current HIV-1 epidemic, and suggest a means of grouping and tracking relationships between viruses through preservation of shared breakpints.
M. C. M. Cheung; M. Schuessler; T. D. Tarbell; A. M. Title
2008-10-31
We present results from numerical modeling of emerging flux regions on the solar surface. The modeling was carried out by means of 3D radiative MHD simulations of the rise of buoyant magnetic flux tubes through the convection zone and into the photosphere. Due to the strong stratification of the convection zone, the rise results in a lateral expansion of the tube into a magnetic sheet, which acts as a reservoir for small-scale flux emergence events at the scale of granulation. The interaction of the convective downflows and the rising magnetic flux undulates it to form serpentine field lines emerging into the photosphere. Observational characteristics including the pattern of emerging flux regions, the cancellation of surface flux and associated high speed downflows, the convective collapse of photospheric flux tubes, the appearance of anomalous darkenings, the formation of bright points and the possible existence of transient kilogauss horizontal fields are discussed in the context of new observations from the Hinode Solar Optical Telescope. Implications for the local helioseismology of emerging flux regions are also discussed.
Algorithms for passive dynamical modeling and passive circuit realizations
Mahmood, Zohaib
2015-01-01
The design of modern electronic systems is based on extensive numerical simulations, aimed at predicting the overall system performance and compliance since early design stages. Such simulations rely on accurate dynamical ...
Modeling the dynamics and depositional patterns of sandy rivers
Jerolmack, Douglas J
2006-01-01
This thesis seeks to advance our understanding of the dynamic nature, spatial organization and depositional record of topography in sand-bedded rivers. I examine patterns and processes over a wide range of scales, on Earth ...
Dynamic reduced order modeling of entrained flow gasifiers
Monaghan, Rory F. D. (Rory Francis Desmond)
2010-01-01
Gasification-based energy systems coupled with carbon dioxide capture and storage technologies have the potential to reduce greenhouse gas emissions from continued use of abundant and secure fossil fuels. Dynamic reduced ...
Advancing understanding of affect labeling with dynamic causal modeling
Torrisi, SJ; Lieberman, MD; Bookheimer, SY; Altshuler, LL
2013-01-01
K.J. , Harrison, L. , Penny, W.D. , 2003. Dynamic causalNeuroimage 22, 1157–1172. Penny, W.D. , Stephan, K.E. ,emotions. Emotion 12, 229–235. Penny, W.D. , 2012. Comparing
A Lagrangian model of Copepod dynamics: clustering by escape jumps in turbulence
Ardeshiri, Hamidreza; Schmitt, François G; Souissi, Sami; Toschi, Federico; Calzavarini, Enrico
2016-01-01
Planktonic copepods are small crustaceans that have the ability to swim by quick powerful jumps. Such an aptness is used to escape from high shear regions, which may be caused either by flow per- turbations, produced by a large predator (i.e. fish larvae), or by the inherent highly turbulent dynamics of the ocean. Through a combined experimental and numerical study, we investigate the impact of jumping behaviour on the small-scale patchiness of copepods in a turbulent environment. Recorded velocity tracks of copepods displaying escape response jumps in still water are here used to define and tune a Lagrangian Copepod (LC) model. The model is further employed to simulate the behaviour of thousands of copepods in a fully developed hydrodynamic turbulent flow obtained by direct numerical simulation of the Navier-Stokes equations. First, we show that the LC velocity statistics is in qualitative agreement with available experimental observations of copepods in tur- bulence. Second, we quantify the clustering of LC...
Impact of Agricultural Practice on Regional Climate in a CoupledLand Surface Mesoscale Model
Cooley, H.S.; Riley, W.J.; Torn, M.S.; He, Y.
2004-07-01
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.
Modeling the dynamic component of the geoid and topography of Venus
Cerveny, Vlastislav
Modeling the dynamic component of the geoid and topography of Venus M. Pauer,1,2 K. Fleming,3 and O. [1] We analyze the Venusian geoid and topography to determine the relative importance of isostatic is whole mantle in style, (2) the long-wavelength geoid and topography are of purely dynamic origin, and (3
Static and dynamic length scales in a simple glassy plaquette model Robert L. Jack,1
Berthier, Ludovic
Static and dynamic length scales in a simple glassy plaquette model Robert L. Jack,1 Ludovic manuscript received 6 April 2005; published 5 July 2005 We study static and dynamic spatial correlations representation where spins are mapped to plaquette variables. We study the interplay between nontrivial static
Dynamic Modeling of Behavior Change H. T. Banks, Keri L. Rehm, Karyn L. Sutton
for investigating dynamic behavior change. While the approach is applicable to behavior change in eating disorders, smoking, substance abuse and other behavioral disorders, here we present our novel dynamical systems modeling approach to understand the processes governing an individual's behavior in the context of problem
Industry Dynamics: Foundations For Models with an Infinite Number of Firms
Van Roy, Ben
Industry Dynamics: Foundations For Models with an Infinite Number of Firms Gabriel Y. Weintraub August, 2010 Abstract This paper explores the connection between three important threads of economic research offering different approaches to studying the dynamics of an industry with heterogeneous firms
NREL: Regional Energy Deployment System (ReEDS) Model - Model Description
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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines lightGeospatial Toolkit TheCompetitiveMattPhotoQualitative Model
COMPUTERS AND BIOMEDICAL RESEARCH 17, 580-589 ( 1984) Multicompartment Model of Lung Dynamics*
Longtin, André
COMPUTERS AND BIOMEDICAL RESEARCH 17, 580-589 ( 1984) Multicompartment Model of Lung Dynamics* B of the lungs. The lungs are represented by 24 compartments each corresponding to a generation of the Weibel model A. In the model it is assumed that gases are transported in the lungs by convection and diffusion
Parasitic castration: a perspective from a model of dynamic energy Spencer R. Hall,1,
Hall, Spencer
of dynamic energy budgets (DEB), we show how these results readily emerge, assuming that parasites consume this model, we compare and contrast two strategies for parasites. ``Consumers'' only steal energy from model of energy flow using a minimal number of assumptions. Finally, the DEB model for both ``consumers
Automated Modeling of Dynamic Reliability Block Diagrams Using Colored Petri Nets
Xu, Haiping
solution to automated verification of DRBD models. Index Terms--System reliability, reliability block \\ Abstract--Computer system reliability is conventionally modeled and analyzed using techniques such as fault), defines a framework for modeling dynamic reliability behavior of computer-based systems. However
Development of a Data Driven Dynamic Model for a Plasma Etching Reactor Michael Nikolaoua)
Nikolaou, Michael
1 Development of a Data Driven Dynamic Model for a Plasma Etching Reactor Michael Nikolaoua for identification and validation of an empirical model for a helicon plasma reactor, on the basis of experimental manufacturing processes such as plasma etching, accurate models based on first principles may be developed
Computational Fluid Dynamics Modeling of a Lithium/Thionyl Chloride Battery with Electrolyte Flow
Wang, Chao-Yang
Computational Fluid Dynamics Modeling of a Lithium/Thionyl Chloride Battery with Electrolyte Flow W-dimensional model is developed to simulate discharge of a primary lithium/thionyl chloride battery. The model to the first task with important examples of lead-acid,1-3 nickel-metal hydride,4-8 and lithium-based batteries
Nonrigid Motion Analysis Based on Dynamic Refinement of Finite Element Models
Sarkar, Sudeep
Nonrigid Motion Analysis Based on Dynamic Refinement of Finite Element Models Leonid V. Tsap finite element models. The method is based on the iterative analysis of the differences betweenĂPhysically-based vision, deformable models, nonrigid motion analysis, biomedical applications, finite element analysis. Ă¦
Haptics-based Volumetric Modeling Using Dynamic Spline-based Implicit Functions
Qin, Hong
Haptics-based Volumetric Modeling Using Dynamic Spline-based Implicit Functions Jing Hua Hong Qin-based volumetric modeling framework, which is founded upon volumetric implicit functions and powerful physics-based modeling. The volumetric implicit functions incorporate hierarchical B-splines, CSG-based functional
Modelling vegetation dynamics at global scale due to climate changes: Comparison of two approaches
Belotelov, N.V.; Bogatyrev, B.G.; Lobanov, A.I.
1996-12-31
Climate changes will influence vegetation dynamics. One of the ways of forecasting these changes is the creation of mathematical models describing vegetation dynamics. Computer experiments can then be conducted under climate change scenarios. Two main approaches are used to create such models. The first approach is based on a bioclimatic dynamic approach. The second approach is based on modelling the main eco-physiological processes. The bioclimatic dynamic approach consists of hypotheses about vegetation types or biomes, and their interrelationships with climate. In the eco-physiological approach, a detailed description of the processes, such as production, mortality, plants migration and their competition is presented. A number of computer experiments has been conducted for several climatic scenario for Russia and the whole world. A qualitative comparison of the results with the results of an earlier bioclimatic model has been done.
Finite Element Modelling and Molecular Dynamic Simulations of Carbon nanotubes/ Polymer Composites
Gaddamanugu, Dhatri
2010-07-14
Modeling of single-walled carbon nanotubes, multi-walled nanotubes and nanotube reinforced polymer composites using both the Finite Element method and the Molecular Dynamic simulation technique is presented. Nanotubes subjected to mechanical loading...
Rojas Paico, Danny H.
2001-01-01
The integration of dynamic data into reservoir models is known as automatic history matching, and it requires the solution of an inverse problem through the minimization of an objective function. The objective function to ...
Seagraves, Andrew Nathan
2010-01-01
In this thesis a new parallel computational method is proposed for modeling threedimensional dynamic fracture of brittle solids. The method is based on a combination of the discontinuous Galerkin (DG) formulation of the ...
A model simulation of white-winged dove population dynamics in the Tamaulipan Biotic Province
Martinez, Cristina Ann
2002-01-01
I present the development, evaluation, and sensitivity analysis of a simulation model representing two components of population dynamics-natality and mortality-for the white-winged dove (Zenaida asiatica asiatica; WWDO). I also discuss the role...
Dynamic Modeling and Wavelet-Based Multi-Parametric Tuning and Validation for HVAC Systems
Liang, Shuangshuang
2014-07-10
Dynamic Heating, Ventilation, and Air-Conditioning (HVAC) system models are used for the purpose of control design, fault detection and diagnosis, system analysis, design and optimization. Therefore, ensuring the accuracy ...
Dynamical Modeling and Multi-Experiment Fitting with PottersWheel Supplement
Timmer, Jens
Dynamical Modeling and Multi-Experiment Fitting with PottersWheel Supplement Thomas Maiwald@fdm.uni-freiburg.de June 10, 2008 Abstract This supplement provides detailed information about the functionalities
A Nonlinear Continuous Time Optimal Control Model of Dynamic Pricing and Inventory Control with no
Adida, Elodie
time optimal control model for studying a dynamic pricing and inventory control problem for a make-to-stock of not introducing any approximation to the real setting: it provides the exact solution of the system. When taking
Dynamic Long-Term Modelling of Generation Capacity Investment and Capacity Margins
Eager, Dan; Hobbs, Benjamin; Bialek, Janusz
2012-04-25
is the mix and amount of generation investment over time in response to policies promoting high penetrations of variable output renewable power such as wind. Modelling the dynamics of merchant generation investment in market environments can inform the debate...
THE EMERGENT STRUCTURE OF THE DROSOPHILA WING A Dynamic Model Generator
Abate, Alessandro
THE EMERGENT STRUCTURE OF THE DROSOPHILA WING A Dynamic Model Generator Alberto Silletti Department packing; 2. then, given a movie (a sequence of frames) of the fly wing, correlate the networks generated
Design of a test apparatus to study a proposed dynamic tissue puncture model
Inman, Kathleen Marie
2013-01-01
Two test apparatuses were designed, built, and evaluated in order to study a proposed dynamic tissue puncture model. The test apparatuses were designed to improve existing experiments used previously to experimentally ...
EEGbased communication via dynamic neural network models William D. Penny and Stephen J. Roberts
Roberts, Stephen
EEGbased communication via dynamic neural network models William D. Penny and Stephen J. Roberts fw.penny, s.j.robertsg@ic.ac.uk Department of Electrical and Electronic Engineering, Imperial College
EEGbased communication via dynamic neural network models William D. Penny and Stephen J. Roberts
Penny, Will
EEGÂbased communication via dynamic neural network models William D. Penny and Stephen J. Roberts fw.penny, s.j.robertsg@ic.ac.uk Department of Electrical and Electronic Engineering, Imperial College
Development of a Dynamic DOE Calibration Model | Department of...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
model was developed. The model can be applied for calibration and control system optimization. p-22anderson.pdf More Documents & Publications Reducing the Particulate Emission...
Sleep Dynamics and Seizure Control in a Mesoscale Cortical Model
Lopour, Beth Ann
2009-01-01
Contributions . . . . . . . . . 2 Mesoscale Cortical Modelstates in h e from the mesoscale cortical model, here- afterand Seizure Control in a Mesoscale Cortical Model by Beth
Chan, Antoni Bert
2008-01-01
a ferris wheel and windmill . . . . . . . . 139 Segmentationa (a) ferris wheel and (b) windmill using LDT and DTM. V.H.3LDT segments the windmill into regions corresponding to the
Force-free field modeling of twist and braiding-induced magnetic energy in an active-region corona
Thalmann, J. K.
2014-01-01
The theoretical concept that braided magnetic field lines in the solar corona may dissipate a sufficient amount of energy to account for the brightening observed in the active-region (AR) corona has only recently been substantiated by high-resolution observations. From the analysis of coronal images obtained with the High Resolution Coronal Imager, first observational evidence of the braiding of magnetic field lines was reported by Cirtain et al. (hereafter CG13). We present nonlinear force-free reconstructions of the associated coronal magnetic field based on Solar Dynamics Observatory/Helioseismic and Magnetic Imager vector magnetograms. We deliver estimates of the free magnetic energy associated with a braided coronal structure. Our model results suggest (?100 times) more free energy at the braiding site than analytically estimated by CG13, strengthening the possibility of the AR corona being heated by field line braiding. We were able to appropriately assess the coronal free energy by using vector field measurements and we attribute the lower energy estimate of CG13 to the underestimated (by a factor of 10) azimuthal field strength. We also quantify the increase in the overall twist of a flare-related flux rope that was noted by CG13. From our models we find that the overall twist of the flux rope increased by about half a turn within 12 minutes. Unlike another method to which we compare our results, we evaluate the winding of the flux rope's constituent field lines around each other purely based on their modeled coronal three-dimensional field line geometry. To our knowledge, this is done for the first time here.
Huang, Zhenyu; Du, Pengwei; Kosterev, Dmitry; Yang, Steve
2013-05-01
Disturbance data recorded by phasor measurement units (PMU) offers opportunities to improve the integrity of dynamic models. However, manually tuning parameters through play-back events demands significant efforts and engineering experiences. In this paper, a calibration method using the extended Kalman filter (EKF) technique is proposed. The formulation of EKF with parameter calibration is discussed. Case studies are presented to demonstrate its validity. The proposed calibration method is cost-effective, complementary to traditional equipment testing for improving dynamic model quality.
Characteristics of identifying linear dynamic models from impulse response data using Prony analysis
Trudnowski, D.J.
1992-12-01
The purpose of the study was to investigate the characteristics of fitting linear dynamic models to the impulse response of oscillatory dynamic systems using Prony analysis. Many dynamic systems exhibit oscillatory responses with multiple modes of oscillations. Although the underlying dynamics of such systems are often nonlinear, it is frequently possible and very useful to represent the system operating about some set point with a linear model. Derivation of such linear models can be done using two basic approaches: model the system using theoretical derivations and some linearization method such as a Taylor series expansion; or use a curve-fitting technique to optimally fit a linear model to specified system response data. Prony analysis belongs to the second class of system modeling because it is a method of fitting a linear model to the impulse response of a dynamic system. Its parallel formulation inherently makes it well suited for fitting models to oscillatory system data. Such oscillatory dynamic effects occur in large synchronous-generator-based power systems in the form of electromechanical oscillations. To study and characterize these oscillatory dynamics, BPA has developed computer codes to analyze system data using Prony analysis. The objective of this study was to develop a highly detailed understanding of the properties of using Prony analysis to fit models to systems with characteristics often encountered in power systems. This understanding was then extended to develop general rules-of-thumb'' for using Prony analysis. The general characteristics were investigated by performing fits to data from known linear models under controlled conditions. The conditions studied include various mathematical solution techniques; different parent system configurations; and a large variety of underlying noise characteristics.
Characteristics of identifying linear dynamic models from impulse response data using Prony analysis
Trudnowski, D.J.
1992-12-01
The purpose of the study was to investigate the characteristics of fitting linear dynamic models to the impulse response of oscillatory dynamic systems using Prony analysis. Many dynamic systems exhibit oscillatory responses with multiple modes of oscillations. Although the underlying dynamics of such systems are often nonlinear, it is frequently possible and very useful to represent the system operating about some set point with a linear model. Derivation of such linear models can be done using two basic approaches: model the system using theoretical derivations and some linearization method such as a Taylor series expansion; or use a curve-fitting technique to optimally fit a linear model to specified system response data. Prony analysis belongs to the second class of system modeling because it is a method of fitting a linear model to the impulse response of a dynamic system. Its parallel formulation inherently makes it well suited for fitting models to oscillatory system data. Such oscillatory dynamic effects occur in large synchronous-generator-based power systems in the form of electromechanical oscillations. To study and characterize these oscillatory dynamics, BPA has developed computer codes to analyze system data using Prony analysis. The objective of this study was to develop a highly detailed understanding of the properties of using Prony analysis to fit models to systems with characteristics often encountered in power systems. This understanding was then extended to develop general ``rules-of-thumb`` for using Prony analysis. The general characteristics were investigated by performing fits to data from known linear models under controlled conditions. The conditions studied include various mathematical solution techniques; different parent system configurations; and a large variety of underlying noise characteristics.
Improvements to Regional Explosion Identification using Attenuation Models of the Lithosphere
Pasyanos, M E; Walter, W R
2009-03-30
Regional P/S amplitudes have been recognized as an effective discriminant between earthquakes and explosions. While closely spaced earthquake and explosions generally discriminate easily, the application of this technique to broad regions has been hampered by large variations in the amplitude of regional phases due to the attenuation structure of the crust and upper mantle. Making use of a recent P-wave and S-wave attenuation model of the lithosphere, we have found that correcting the events using our amplitude methodology significantly reduces the scattering in the earthquake population. We demonstrate an application of this technique to station NIL (Nilore, Pakistan) using broad area earthquakes and the 1998 Indian nuclear explosion recorded at the station using the Pn/Lg discriminant in the 1-2 Hz passband. We find that the explosion, which is lost in the scatter of the earthquakes in the uncorrected discriminant, clearly separates by correcting for the attenuation structure. We see a similar reduction in scatter and separation for the Pn/Sn and Pg/Lg discriminants in the same passband.
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.
2015-01-01
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.
A dynamic model for underbalanced drilling with coiled tubing
Rommetveit, R.; Vefring, E.H.; Wang, Z.; Bieseman, T.; Faure, A.M.
1995-11-01
A model for underbalanced drilling with coiled tubing has been developed which takes into account all important factors contributing to the process. This model is a unique tool to plan and execute underbalanced or near balance drilling operations. It is a transient, one-dimensional multi-phase flow model with the following components: Lift gas system model, multiphase hydraulics model, reservoir-wellbore interaction model, drilling model, models for multiphase fluids (lift gas, produced gas, mud, foam, produced gas, oil, water and cuttings). Various alternative geometries for gas injection are modeled as well as all important operations during underbalanced drilling with coiled tubing. The model as well as some simulation results for its use are presented in this paper.
Wang, Shaobu; Lu, Shuai; Zhou, Ning; Lin, Guang; Elizondo, Marcelo A.; Pai, M. A.
2014-09-04
In interconnected power systems, dynamic model reduction can be applied on generators outside the area of interest to mitigate the computational cost with transient stability studies. This paper presents an approach of deriving the reduced dynamic model of the external area based on dynamic response measurements, which comprises of three steps, dynamic-feature extraction, attribution and reconstruction (DEAR). In the DEAR approach, a feature extraction technique, such as singular value decomposition (SVD), is applied to the measured generator dynamics after a disturbance. Characteristic generators are then identified in the feature attribution step for matching the extracted dynamic features with the highest similarity, forming a suboptimal ‘basis’ of system dynamics. In the reconstruction step, generator state variables such as rotor angles and voltage magnitudes are approximated with a linear combination of the characteristic generators, resulting in a quasi-nonlinear reduced model of the original external system. Network model is un-changed in the DEAR method. Tests on several IEEE standard systems show that the proposed method gets better reduction ratio and response errors than the traditional coherency aggregation methods.
Chapter 18: Understanding the Developing Cellulosic Biofuels Industry through Dynamic Modeling
Newes, E.; Inman, D.; Bush, B.
2011-01-01
The purpose of this chapter is to discuss a system dynamics model called the Biomass Scenario Model (BSM), which is being developed by the U.S. Department of Energy as a tool to better understand the interaction of complex policies and their potential effects on the burgeoning cellulosic biofuels industry in the United States. The model has also recently been expanded to include advanced conversion technologies and biofuels (i.e., conversion pathways that yield biomass-based gasoline, diesel, jet fuel, and butanol), but we focus on cellulosic ethanol conversion pathways here. The BSM uses a system dynamics modeling approach (Bush et al., 2008) built on the STELLA software platform.
A One-Dimensional (1-D) Three-Region Model for a Bubbling Fluidized-Bed Adsorber
Lee, Andrew; Miller, David C.
2012-01-01
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.
A nanoflare model for active region radiance: application of artificial neural networks
M. Bazarghan; H. Safari; D. E. Innes; E. Karami; S. K. Solanki
2008-12-20
Context. Nanoflares are small impulsive bursts of energy that blend with and possibly make up much of the solar background emission. Determining their frequency and energy input is central to understanding the heating of the solar corona. One method is to extrapolate the energy frequency distribution of larger individually observed flares to lower energies. Only if the power law exponent is greater than 2, is it considered possible that nanoflares contribute significantly to the energy input. Aims. Time sequences of ultraviolet line radiances observed in the corona of an active region are modelled with the aim of determining the power law exponent of the nanoflare energy distribution. Methods. A simple nanoflare model based on three key parameters (the flare rate, the flare duration time, and the power law exponent of the flare energy frequency distribution) is used to simulate emission line radiances from the ions Fe XIX, Ca XIII, and Si iii, observed by SUMER in the corona of an active region as it rotates around the east limb of the Sun. Light curve pattern recognition by an Artificial Neural Network (ANN) scheme is used to determine the values. Results. The power law exponents, alpha 2.8, 2.8, and 2.6 for Fe XIX, Ca XIII, and Si iii respectively. Conclusions. The light curve simulations imply a power law exponent greater than the critical value of 2 for all ion species. This implies that if the energy of flare-like events is extrapolated to low energies, nanoflares could provide a significant contribution to the heating of active region coronae.
Gerber, Edwin
Heat and freshwater exchange on the Antarctic continental1" shelf in a regional coupled climate, South Korea 120-749. Email:21" cyoo@cims.nyu.edu.22" #12;2" Abstract23" Understanding heat. This study analyzes the heat and freshwater budget using a regional25" coupled climate model, which has been
Dynamic Model Validation of PV Inverters Under Short-Circuit Conditions: Preprint
Muljadi, E.; Singh, M.; Bravo, R.; Gevorgian, V.
2013-03-01
Photovoltaic (PV) modules have dramatically decreased in price in the past few years, spurring the expansion of photovoltaic deployment. Residential and commercial rooftop installations are connected to the distribution network; large-scale installation PV power plants (PVPs) have benefited from tax incentives and the low cost of PV modules. As the level penetration of PV generation increases, the impact on power system reliability will also be greater. Utility power system planners must consider the role of PV generation in power systems more realistically by representing PV generation in dynamic stability analyses. Dynamic models of PV inverters have been developed in the positive sequence representation. NREL has developed a PV inverter dynamic model in PSCAD/EMTDC. This paper validates the dynamic model with an actual hardware bench test conducted by Southern California Edison's Distributed Energy Resources laboratory. All the fault combinations -- symmetrical and unsymmetrical -- were performed in the laboratory. We compare the simulation results with the bench test results.
Voisin, Nathalie; Li, Hongyi; Ward, Duane L.; Huang, Maoyi; Wigmosta, Mark S.; Leung, Lai-Yung R.
2013-09-30
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.
Single cell growth and gene expression dynamics in model organisms
Cookson, Natalie Anne
2009-01-01
technology, and computational modeling, we can begin to probe and even mimic native network architecture and high-
Gedeon, Tomas
, from those appearing in physiology and ecology to Earth systems modeling, often experience critical
Bravo de la Parra, Rafael
Effects of density dependent sex allocation on the dynamics of a simultaneous hermaphroditic Available online 22 December 2009 Keywords: Sex-allocation model Sex-structured population dynamics Density model describing the dynamics of a population where sex allocation remains flexible throughout adult
Dynamical systems modeling of Continuous Flash Suppression Daisuke Shimaoka
Kaneko, Kunihiko
: Binocular rivalry Adaptation Neural modeling a b s t r a c t Continuous Flash Suppression (CFS is considered to be involved in CFS, but does not reproduce CFS. We then extend the model by including of visibility observed in CFS. In addition, this model captured some defining characteristics of CFS
Subin, Z.M.; Riley, W.J.; Kueppers, L.M.; Jin, J.; Christianson, D.S.; Torn, M.S.
2010-11-01
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.
Liese, Eric [U.S. DOE; Zitney, Stephen E. [U.S. DOE
2013-01-01
Research in dynamic process simulation for integrated gasification combined cycles (IGCC) with carbon capture has been ongoing at the National Energy Technology Laboratory (NETL), culminating in a full operator training simulator (OTS) and immersive training simulator (ITS) for use in both operator training and research. A derivative work of the IGCC dynamic simulator has been a modification of the combined cycle section to more closely represent a typical natural gas fired combined cycle (NGCC). This paper describes the NGCC dynamic process model and highlights some of the simulator’s current capabilities through a particular startup and shutdown scenario.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Wyant, M. C.; Bretherton, Christopher S.; Wood, Robert; Carmichael, Gregory; Clarke, A. D.; Fast, Jerome D.; George, R.; Gustafson, William I.; Hannay, Cecile; Lauer, Axel; et al
2015-01-09
A diverse collection of models are used to simulate the marine boundary layer in the southeast Pacific region during the period of the October–November 2008 VOCALS REx (VAMOS Ocean Cloud Atmosphere Land Study Regional Experiment) field campaign. Regional models simulate the period continuously in boundary-forced free-running mode, while global forecast models and GCMs (general circulation models) are run in forecast mode. The models are compared to extensive observations along a line at 20° S extending westward from the South American coast. Most of the models simulate cloud and aerosol characteristics and gradients across the region that are recognizably similar tomore »observations, despite the complex interaction of processes involved in the problem, many of which are parameterized or poorly resolved. Some models simulate the regional low cloud cover well, though many models underestimate MBL (marine boundary layer) depth near the coast. Most models qualitatively simulate the observed offshore gradients of SO2, sulfate aerosol, CCN (cloud condensation nuclei) concentration in the MBL as well as differences in concentration between the MBL and the free troposphere. Most models also qualitatively capture the decrease in cloud droplet number away from the coast. However, there are large quantitative intermodel differences in both means and gradients of these quantities. Many models are able to represent episodic offshore increases in cloud droplet number and aerosol concentrations associated with periods of offshore flow. Most models underestimate CCN (at 0.1% supersaturation) in the MBL and free troposphere. The GCMs also have difficulty simulating coastal gradients in CCN and cloud droplet number concentration near the coast. The overall performance of the models demonstrates their potential utility in simulating aerosol–cloud interactions in the MBL, though quantitative estimation of aerosol–cloud interactions and aerosol indirect effects of MBL clouds with these models remains uncertain.« less
Wyant, M. C.; Bretherton, Christopher S.; Wood, Robert; Carmichael, Gregory; Clarke, A. D.; Fast, Jerome D.; George, R.; Gustafson, William I.; Hannay, Cecile; Lauer, Axel; Lin, Yanluan; Morcrette, J. -J.; Mulcahay, Jane; Saide, Pablo; Spak, S. N.; Yang, Qing
2015-01-01
A diverse collection of models are used to simulate the marine boundary layer in the southeast Pacific region during the period of the October–November 2008 VOCALS REx (VAMOS Ocean Cloud Atmosphere Land Study Regional Experiment) field campaign. Regional models simulate the period continuously in boundary-forced free-running mode, while global forecast models and GCMs (general circulation models) are run in forecast mode. The models are compared to extensive observations along a line at 20° S extending westward from the South American coast. Most of the models simulate cloud and aerosol characteristics and gradients across the region that are recognizably similar to observations, despite the complex interaction of processes involved in the problem, many of which are parameterized or poorly resolved. Some models simulate the regional low cloud cover well, though many models underestimate MBL (marine boundary layer) depth near the coast. Most models qualitatively simulate the observed offshore gradients of SO_{2}, sulfate aerosol, CCN (cloud condensation nuclei) concentration in the MBL as well as differences in concentration between the MBL and the free troposphere. Most models also qualitatively capture the decrease in cloud droplet number away from the coast. However, there are large quantitative intermodel differences in both means and gradients of these quantities. Many models are able to represent episodic offshore increases in cloud droplet number and aerosol concentrations associated with periods of offshore flow. Most models underestimate CCN (at 0.1% supersaturation) in the MBL and free troposphere. The GCMs also have difficulty simulating coastal gradients in CCN and cloud droplet number concentration near the coast. The overall performance of the models demonstrates their potential utility in simulating aerosol–cloud interactions in the MBL, though quantitative estimation of aerosol–cloud interactions and aerosol indirect effects of MBL clouds with these models remains uncertain.
The Dynamics of Subhalos in Warm Dark Matter Models
Alexander Knebe; Bastian Arnold; Chris Power; Brad K. Gibson
2008-02-12
We present a comparison of the properties of substructure halos (subhalos) orbiting within host halos that form in Cold Dark Matter (CDM) and Warm Dark Matter (WDM) cosmologies. Our study focuses on selected properties of these subhalos, namely their anisotropic spatial distribution within the hosts; the existence of a "backsplash'' population; the age-distance relation; the degree to which they suffer mass loss; and the distribution of relative (infall) velocities with respect to the hosts. We find that the number density of subhalos in our WDM model is suppressed relative to that in the CDM model, as we would expect. Interestingly, our analysis reveals that backsplash subhalos exist in both the WDM and CDM models. Indeed, there are no statistically significant differences between the spatial distributions of subhalos in the CDM and WDM models. There is evidence that subhalos in the WDM model suffer enhanced mass loss relative to their counterparts in the CDM model, reflecting their lower central densities. We note also a tendency for the (infall) velocities of subhalos in the WDM model to be higher than in the CDM model. Nevertheless, we conclude that observational tests based on either the spatial distribution or the kinematics of the subhalo population are unlikely to help us to differentiate between the CDM model and our adopted WDM model.
Wang, Yuqing
, and development of regional earth system models. It is believed that with the demonstrated credibility of RCMs
Hammes-Schiffer, Sharon
Proton-coupled electron transfer reactions in solution: Molecular dynamics with quantum transitions A general minimal model for proton-coupled electron transfer PCET reactions in solution is presented. This model consists of three coupled degrees of freedom that represent an electron, a proton, and a solvent
renewal while the daughter stem cell remains in the niche; each stem cell is ``immortal'' under this modelCommentary Methylation patterns and mathematical models reveal dynamics of stem cell turnover in diseases such as cancer, it is essential to understand the process of somatic cell development and renewal
Discrete molecular dynamics studies of the folding of a protein-like model
Buldyrev, Sergey
Discrete molecular dynamics studies of the folding of a protein-like model Nikolay V Dokholyan1 to resolve in time the folding of model proteins in computer simulations. Different computational approaches). Results: We used the recently proposed approach of Zhou and Karplus to study the folding of a protein
Sand dune dynamics and climate change: A modeling H. Yizhaq,1
Ashkenazy, Yossi "Yosef"
Sand dune dynamics and climate change: A modeling approach H. Yizhaq,1 Y. Ashkenazy,1 and H. Tsoar2] We provide several examples for the coexistence of active and fixed sand dunes under similar climatic conditions, namely, with respect to wind power and precipitation rate. A model is developed for dune
Dang, Zhe
Bond Computing Systems: a Biologically Inspired and High-level Dynamics Model for Pervasive their com- putation power and verification problems. Among other results, we show that the computing power) techniques for pervasive computing systems. At a high-level, there are at least two views in modeling
Model-Lite Planning: Diverse Multi-Option Plans & Dynamic Objective Functions Daniel Bryce
Kambhampati, Subbarao
Model-Lite Planning: Diverse Multi-Option Plans & Dynamic Objective Functions Daniel Bryce}@asu.edu Abstract Knowledge acquisition is one major bottle-neck in using planning systems. Model-lite planning reduces this burden by placing responsibility on the planning system to cope with partially specified
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
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 Diffusion Model in Population Genetics with Mutation and Dynamic Fitness
O'Leary, Michael
A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness Mike O'Leary Department of Mathematics Towson University PDE Seminar Vanderbilt University November 2008 Mike O'Leary (Towson University are joint with Judith Miller, Georgetown University. Mike O'Leary (Towson University) A Diffusion Model
Mehmood et al. Paper No. 03-2158 1 Modeling Car-following Using System Dynamics
Hellinga, Bruce
Mehmood et al. Paper No. 03-2158 1 Modeling Car-following Using System Dynamics ARIF MEHMOOD, BRUCE2L 3G1, Canada. E-mail: amehmood@uwaterloo.ca Car following models describe driver behavior of relationships that do not correspond to physical aspects of the car- following process. In this paper we
Generalized models as a universal approach to the analysis of nonlinear dynamical systems
Thilo Gross; Ulrike Feudel
2006-01-29
We present a universal approach to the investigation of the dynamics in generalized models. In these models the processes that are taken into account are not restricted to specific functional forms. Therefore a single generalized models can describe a class of systems which share a similar structure. Despite this generality, the proposed approach allows us to study the dynamical properties of generalized models efficiently in the framework of local bifurcation theory. The approach is based on a normalization procedure that is used to identify natural parameters of the system. The Jacobian in a steady state is then derived as a function of these parameters. The analytical computation of local bifurcations using computer algebra reveals conditions for the local asymptotic stability of steady states and provides certain insights on the global dynamics of the system. The proposed approach yields a close connection between modelling and nonlinear dynamics. We illustrate the investigation of generalized models by considering examples from three different disciplines of science: a socio-economic model of dynastic cycles in china, a model for a coupled laser system and a general ecological food web.
British Columbia, University of
2008-01-01
Journal of Biomechanics 41 (2008) 10691076 A dynamic model of jaw and hyoid biomechanics during Our understanding of human jaw biomechanics has been enhanced by computational modelling et al., 2002; Curtis et al., 1997; Hamdy et al., 2000; Bakke et al., 2007). Its biomechanics however
Molecular Dynamics modelling of the adhesive interaction between fine F. A. Gilabert
Krivtsov, Anton M.
Molecular Dynamics modelling of the adhesive interaction between fine particles F. A. Gilabert the frictionless adhesive interaction force between two fine cohesive polymer grains. The model consists of three a higher resolution near the contact area. Secondly, the cohesion strength (i.e., the work of adhesion
A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic simulations Characterizing and optimizing overall performance of wind plants composed of large numbers at the National Renewable Energy Laboratory (NREL) are coupling physical models of the atmosphere and wind
El Nino duration time (month) Dynamic coupling of an ENSO model to the
Goelzer, Heiko
El Nino duration time (month) Dynamic coupling of an ENSO model to the global coupled climate model changes in the thermohaline circulation and changes in the El Nino/Southern Oscillation (ENSO), the Zebiak distribution El Nino event interval (month) · Interval between ENSO events shifted towards longer times
Aalborg Universitet Modelling and Validation of Water Hydration of PEM Fuel Cell Membrane in Dynamic
Liso, Vincenzo
Aalborg Universitet Modelling and Validation of Water Hydration of PEM Fuel Cell Membrane of Water Hydration of PEM Fuel Cell Membrane in Dynamic Operations. In ECS Transactions. (Vol. 68). ECS from vbn.aau.dk on: november 29, 2015 #12;Modelling and Validation of Water Hydration of PEM Fuel Cell
Coupling remote sensing with computational fluid dynamics modelling to estimate lake chlorophyll form 17 October 2000; accepted 1 June 2001 Abstract A remotely sensed image of Loch Leven, a shallow in the remotely sensed image. It is proposed that CFD modelling benefits the interpretation of remotely sensed
Theoretical modeling of propagation of magneto-acoustic waves in magnetic regions below sunspots
E. Khomenko; A. Kosovichev; M. Collados; K. Parchevsky; V. Olshevsky
2008-12-10
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.
Representation of Dormant and Active Microbial Dynamics for Ecosystem Modeling
Wang, Gangsheng; Mayes, Melanie; Gu, Lianhong; Schadt, Christopher Warren
2014-01-01
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.
Dynamic Models for Wind Turbines and Wind Power Plants
Singh, M.; Santoso, S.
2011-10-01
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.
Data Driven Approach for High Resolution Population Distribution and Dynamics Models
Bhaduri, Budhendra L; Bright, Eddie A; Rose, Amy N; Liu, Cheng; Urban, Marie L; Stewart, Robert N
2014-01-01
High resolution population distribution data are vital for successfully addressing critical issues ranging from energy and socio-environmental research to public health to human security. Commonly available population data from Census is constrained both in space and time and does not capture population dynamics as functions of space and time. This imposes a significant limitation on the fidelity of event-based simulation models with sensitive space-time resolution. This paper describes ongoing development of high-resolution population distribution and dynamics models, at Oak Ridge National Laboratory, through spatial data integration and modeling with behavioral or activity-based mobility datasets for representing temporal dynamics of population. The model is resolved at 1 km resolution globally and describes the U.S. population for nighttime and daytime at 90m. Integration of such population data provides the opportunity to develop simulations and applications in critical infrastructure management from local to global scales.
Modekurti, Srinivasarao; Bhattacharyya, Debangsu; Zitney, Stephen E.
2013-07-31
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 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
2012-01-01
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.
Dynamic modelling of chorded mitral valves inside left ventricle
Luo, Xiaoyu
model. This model allows us to investigate the influences of the flow vortex generated by the LV motion and swirls around in a clockwise fashion, forming a main clockwise vortex. This vortex persists through inside a tube, where the forward jet is accompanied by two vortices at each side. References
Cognitive Modeling Formulation and Analysis of Dynamic Systems
Bremen, Universität
trajectories produced by a local generator. #12;7 Logistic Growth Model Define p(t) as the probability affects the output (or, vice-versa, what inputs should be given to generate a desired output for the n-element binary valued lists. The state space of a brain model is the set of points contained
Modeling Temporal Activity Patterns in Dynamic Social Networks
Raghavan, Vasanthan; Galstyan, Aram; Tartakovsky, Alexander G
2013-01-01
The focus of this work is on developing probabilistic models for user activity in social networks by incorporating the social network influence as perceived by the user. For this, we propose a coupled Hidden Markov Model, where each user's activity evolves according to a Markov chain with a hidden state that is influenced by the collective activity of the friends of the user. We develop generalized Baum-Welch and Viterbi algorithms for model parameter learning and state estimation for the proposed framework. We then validate the proposed model using a significant corpus of user activity on Twitter. Our numerical studies show that with sufficient observations to ensure accurate model learning, the proposed framework explains the observed data better than either a renewal process-based model or a conventional uncoupled Hidden Markov Model. We also demonstrate the utility of the proposed approach in predicting the time to the next tweet. Finally, clustering in the model parameter space is shown to result in dist...
Modeling the dynamics of a tracer particle in an elastic active gel
E. Ben Isaac; É. Fodor; P. Visco; F. van Wijland; N. S. Gov
2015-07-03
The internal dynamics of active gels, both in artificial (in-vitro) model systems and inside the cytoskeleton of living cells, has been extensively studied by experiments of recent years. These dynamics are probed using tracer particles embedded in the network of biopolymers together with molecular motors, and distinct non-thermal behavior is observed. We present a theoretical model of the dynamics of a trapped active particle, which allows us to quantify the deviations from equilibrium behavior, using both analytic and numerical calculations. We map the different regimes of dynamics in this system, and highlight the different manifestations of activity: breakdown of the virial theorem and equipartition, different elasticity-dependent "effective temperatures" and distinct non-Gaussian distributions. Our results shed light on puzzling observations in active gel experiments, and provide physical interpretation of existing observations, as well as predictions for future studies.
Modeling the dynamics of a tracer particle in an elastic active gel
Isaac, E Ben; Visco, P; van Wijland, F; Gov, N S
2015-01-01
The internal dynamics of active gels, both in artificial (in-vitro) model systems and inside the cytoskeleton of living cells, has been extensively studied by experiments of recent years. These dynamics are probed using tracer particles embedded in the network of biopolymers together with molecular motors, and distinct non-thermal behavior is observed. We present a theoretical model of the dynamics of a trapped active particle, which allows us to quantify the deviations from equilibrium behavior, using both analytic and numerical calculations. We map the different regimes of dynamics in this system, and highlight the different manifestations of activity: breakdown of the virial theorem and equipartition, different elasticity-dependent "effective temperatures" and distinct non-Gaussian distributions. Our results shed light on puzzling observations in active gel experiments, and provide physical interpretation of existing observations, as well as predictions for future studies.
Modeling microbial dynamics in heterogeneous environments: Growth on soil carbon sources
Resat, Haluk; Bailey, Vanessa L.; McCue, Lee Ann; Konopka, Allan
2012-01-01
We have developed a new hybrid model to study how microbial dynamics are affected by the heterogeneity in the physical structure of the environment. The modeling framework can represent porous media such as soil. The individual based biological model can explicitly simulate microbial diversity, and cell metabolism is regulated via optimal allocation of cellular resources to enzyme synthesis, control of growth rate by protein synthesis capacity, and shifts to dormancy. This model was developed to study how microbial community functioning is influenced by local environmental conditions and by the functional attributes of individual microbes. Different strategies for acquisition of carbon from polymeric cellulose were investigated. Bacteria that express membrane-associated hydrolase had different growth and survival dynamics in soil pores than bacteria that release extracellular hydrolases. The kinetic differences may suggest different functional roles for these two classes of microbes in cellulose utilization. Our model predicted an emergent behavior in which co-existence led to higher cellulose utilization efficiency and reduced stochasticity. Microbial community dynamics were simulated at two spatial scales: micro-pores that resemble 6-20 {micro}m size portions of the soil physical structure and in 111 {micro}m size soil aggregates with a random pore structure. Trends in dynamic properties were very similar at these two scales, implying that micro-scale studies can be useful approximations to aggregate scale studies when local effects on microbial dynamics are studied.
Dynamic (G2) Model Design Document, 24590-WTP-MDD-PR-01-002, Rev. 12
Deng, Yueying; Kruger, Albert A.
2013-12-16
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.
phytoplanktonzooplankton food web model in the Oyashio region Shin-ichi Ito a, , Naoki Yoshie b , Takeshi Okunishi c , Tsuneo without ontogenetic vertical migration of the large zooplankton functional group. Determining or averaged state variables were used, in whether state variables were model functional groups or were
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.
2007-08-01
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.
Dynamic modeling of a single-stage downward firing, entrained flow gasifier
Kasule, J., Turton, R., Bhattacharyya, D., Zitney, S.
2012-01-01
The gasifier is the heart of the integrated gasification combined cycle (IGCC), a technology that has emerged as an attractive alternative to conventional coal-fired power plant technology due to its higher efficiency and cleaner environmental performance especially with the option of CO{sub 2} capture and sequestration. Understanding the optimal performance of the gasifier is therefore paramount for the efficient operation of IGCC power plants. Numerous gasifier models of varying complexity have been developed to study the various aspects of gasifier performance. These range from simple one-dimensional (1D) process-type models to rigorous higher order 2-3D models based on computational fluid dynamics (CFD). Whereas high-fidelity CFD models can accurately predict most key aspects of gasifier performance, they are computationally expensive and typically take hours to days to execute on high-performance computers. Therefore, faster 1D partial differential equation (PDE)-based models are required for use in dynamic simulation studies, control system analysis, and training applications. A number of 1D gasifier models can be found in the literature, but most are steady-state models that have limited application in the practical operation of the gasifier. As a result, 1D PDE-based dynamic models are needed to further study and predict gasifier performance under a wide variety of process conditions and disturbances. In the current study, a 1D transient model of a single-stage downward-fired GE/Texaco-type entrained-flow gasifier has been developed. The model comprises mass, momentum and energy balances for the gas and solid phases. The model considers the initial gasification processes of water evaporation and coal devolatilization. In addition, the key heterogeneous and homogeneous chemical reactions have been modeled. The resulting time-dependent PDE model is solved using the well-known method of lines approach in Aspen Custom Modeler®, whereby the PDEs in the spatial domain are discretized and the resulting differential algebraic equations (DAEs) are then integrated over time using a dynamic integrator. The dynamic response results of the gasifier performance parameters to certain disturbances commonly encountered during practical operation are presented. These disturbances include ramp and step changes to input variables such as coal flow rate, oxygen-to-coal ratio and water-to-coal ratio among others. Comparison of model predictions to available dynamic data will also be discussed.
Dynamics of the Oil Transition: Modeling Capacity, Costs, and Emissions
Brandt, Adam R.; Farrell, Alexander E.
2008-01-01
and income on energy and oil demand. Energy Journal, 23(1):conventional oil supply and demand. But, interestingly,World crude oil and natural gas: a demand and supply model.
Time consistency and risk averse dynamic decision models ...
2013-05-02
sistent models as we provide practitioners with an intuitive economic inter- pretation for the ... ning and financial engineering problems. Based on ... consistency is shown to be one basic requirement to get suitable optimal de- cisions, in ...
Model for Dynamic Self-Assembled Magnetic Surface Structures
M. Belkin; A. Glatz; A. Snezhko; I. S. Aranson
2010-02-02
We propose a first-principles model for self-assembled magnetic surface structures on the water-air interface reported in earlier experiments \\cite{snezhko2,snezhko4}. The model is based on the Navier-Stokes equation for liquids in shallow water approximation coupled to Newton equations for interacting magnetic particles suspended on the water-air interface. The model reproduces most of the observed phenomenology, including spontaneous formation of magnetic snake-like structures, generation of large-scale vortex flows, complex ferromagnetic-antiferromagnetic ordering of the snake, and self-propulsion of bead-snake hybrids. The model provides valuable insights into self-organization phenomena in a broad range of non-equilibrium magnetic and electrostatic systems with competing interactions.
Stochastic Modeling and Analysis of Pathway Regulation and Dynamics
Zhao, Chen
2012-07-16
called masters or canalizing genes. Characterizing and detecting such genes are thus highly valuable for the treatment of cancer. Chapter II is devoted to this task, where we present a Bayesian framework to model pathway interactions and then study...
Wang, Gangsheng; Post, Wilfred M; Mayes, Melanie
2013-01-01
We developed a Microbial-ENzyme-mediated Decomposition (MEND) model, based on the Michaelis-Menten kinetics, that describes the dynamics of physically defined pools of soil organic matter (SOC). These include particulate, mineral-associated, dissolved organic matter (POC, MOC, and DOC, respectively), microbial biomass, and associated exoenzymes. The ranges and/or distributions of parameters were determined by both analytical steady-state and dynamic analyses with SOC data from the literature. We used an improved multi-objective parameter sensitivity analysis (MOPSA) to identify the most important parameters for the full model: maintenance of microbial biomass, turnover and synthesis of enzymes, and carbon use efficiency (CUE). The model predicted an increase of 2 C (baseline temperature =12 C) caused the pools of POC-Cellulose, MOC, and total SOC to increase with dynamic CUE and decrease with constant CUE, as indicated by the 50% confidence intervals. Regardless of dynamic or constant CUE, the pool sizes of POC, MOC, and total SOC varied from 8% to 8% under +2 C. The scenario analysis using a single parameter set indicates that higher temperature with dynamic CUE might result in greater net increases in both POC-Cellulose and MOC pools. Different dynamics of various SOC pools reflected the catalytic functions of specific enzymes targeting specific substrates and the interactions between microbes, enzymes, and SOC. With the feasible parameter values estimated in this study, models incorporating fundamental principles of microbial-enzyme dynamics can lead to simulation results qualitatively different from traditional models with fast/slow/passive pools.
Ris-R-1400(EN) Dynamic wind turbine models in power
Risř-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
On the Characterization of Classical Dynamical Systems Using Supersymmetric Nonlinear $?$-models
A. J. Niemi; K. Palo
1995-03-13
We construct a two dimensional nonlinear $\\sigma$-model that describes the Hamiltonian flow in the loop space of a classical dynamical system. This model is obtained by equivariantizing the standard N=1 supersymmetric nonlinear $\\sigma$-model by the Hamiltonian flow. We use localization methods to evaluate the corresponding partition function for a general class of integrable systems, and find relations that can be viewed as generalizations of standard relations in classical Morse theory.
Winguth, Arne
a dynamic Earth system model A. Winguth Center for Climatic Research, Department of Atmospheric and Oceanic; accepted 26 October 2005; published 15 December 2005. [1] A complex Earth system model including atmosphere and anthropogenic climate change using a dynamic Earth system model, Geophys. Res. Lett., 32, L23714, doi:10
A dynamic battery model for co-design in cyber-physical systems Fumin Zhang, Zhenwu Shi
Zhang, Fumin
A dynamic battery model for co-design in cyber-physical systems Fumin Zhang, Zhenwu Shi School, Georgia 30332 Email: wolf@ece.gatech.edu Abstract We introduce a dynamic battery model that describes the variations of the capacity of a battery under time varying discharge current. This model supports a co
Stochastic Wilson-Cowan models of neuronal network dynamics with memory and delay
Goychuk, Igor
2015-01-01
We consider a simple Markovian class of the stochastic Wilson-Cowan type models of neuronal network dynamics, which incorporates stochastic delay caused by the existence of a refractory period of neurons. From the point of view of the dynamics of the individual elements, we are dealing with a network of non-Markovian stochastic two-state oscillators with memory which are coupled globally in a mean-field fashion. This interrelation of a higher-dimensional Markovian and lower-dimensional non-Markovian dynamics is discussed in its relevance to the general problem of the network dynamics of complex elements possessing memory. The simplest model of this class is provided by a three-state Markovian neuron with one refractory state, which causes firing delay with an exponentially decaying memory within the two-state reduced model. This basic model is used to study critical avalanche dynamics (the noise sustained criticality) in a balanced feedforward network consisting of the excitatory and inhibitory neurons. Such ...
Boutchko, R.
2014-01-01
emission tomography systems and computational fluid dynamicsa computational ?uid dynamics (CFD) model of the systemthe computational domain. A Cartesian coordinate system was
Dynamic Delayed Duplicate Detection for External Memory Model Checking
Evangelista, Sami
is a method to prove that finite state systems match their spec- ification. Given a model of the system space, of the system to check the validity of the property. Despite its simplicity, its practical to benefit from the aggregate computational power and memory of a cluster of machines, or make use
Dynamic Partial Order Reduction for Relaxed Memory Models Naling Zhang
Wang, Chao
Tech Blacksburg, VA, USA chaowang@vt.edu Abstract Under a relaxed memory model such as TSO or PSO reduction (POR) algorithm for verify- ing concurrent programs under TSO and PSO. Our method relies techniques to TSO and PSO without overhauling the verification algorithm. In addition to sound POR, we also
Dynamic modeling and learning user profile in personalized news agent
Widyantoro, Dwi Hendratmo
1999-01-01
result, many software agents have been employed to perform autonomous information gathering and altering on behalf of the user. One of the critical issues in such an agent is the capability of the agent to model its users and adapt itself over time...
Dynamical regimes in neural network models of matching behavior
Columbia University
models have been proposed to explain the matching behavior observed in the experiments. Here we study, several theoretical works explain the matching behavior observed in ex- periments (Sugrue et al., 2004 the matching behavior observed in experiments in which monkeys are trained to choose between two visual targets
Update on Small Modular Reactors Dynamics System Modeling Tool -- Molten Salt Cooled Architecture
Hale, Richard Edward; Cetiner, Sacit M.; Fugate, David L.; Qualls, A L.; Borum, Robert C.; Chaleff, Ethan S.; Rogerson, Doug W.; Batteh, John J.; Tiller, Michael M.
2014-08-01
The Small Modular Reactor (SMR) Dynamic System Modeling Tool project is in the third year of development. The project is designed to support collaborative modeling and study of various advanced SMR (non-light water cooled) concepts, including the use of multiple coupled reactors at a single site. The objective of the project is to provide a common simulation environment and baseline modeling resources to facilitate rapid development of dynamic advanced reactor SMR models, ensure consistency among research products within the Instrumentation, Controls, and Human-Machine Interface (ICHMI) technical area, and leverage cross-cutting capabilities while minimizing duplication of effort. The combined simulation environment and suite of models are identified as the Modular Dynamic SIMulation (MoDSIM) tool. The critical elements of this effort include (1) defining a standardized, common simulation environment that can be applied throughout the program, (2) developing a library of baseline component modules that can be assembled into full plant models using existing geometry and thermal-hydraulic data, (3) defining modeling conventions for interconnecting component models, and (4) establishing user interfaces and support tools to facilitate simulation development (i.e., configuration and parameterization), execution, and results display and capture.
Ding, Kai; Fuld, Matthew K; Du, Kaifang; Christensen, Gary E; Hoffman, Eric A; Reinhardt, Joseph M
2012-01-01
Purpose: Regional lung volume change as a function of lung inflation serves as an index of parenchymal and airway status as well as an index of regional ventilation and can be used to detect pathologic changes over time. In this article, we propose a new regional measure of lung mechanics --- the specific air volume change by corrected Jacobian. Methods: 4DCT and Xe-CT data sets from four adult sheep are used in this study. Nonlinear, 3D image registration is applied to register an image acquired near end inspiration to an image acquired near end expiration. Approximately 200 annotated anatomical points are used as landmarks to evaluate registration accuracy. Three different registration-based measures of regional lung mechanics are derived and compared: the specific air volume change calculated from the Jacobian (SAJ); the specific air volume change calculated by the corrected Jacobian (SACJ); and the specific air volume change by intensity change (SAI). Results: After registration, the mean registration err...
Multiple higher-order singularities and iso-dynamics in a simple glass-former model
Nicoletta Gnan; Gayatri Das; Matthias Sperl; Francesco Sciortino; Emanuela Zaccarelli
2014-07-15
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.
Modelling the Structure and Dynamics of Science Using Books
Ginda, Michael; Borner, Katy
2015-01-01
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...
Modelling Dynamic Constraints in Electricity Markets and the Costs of Uncertain Wind Output
Musgens, Felix; Neuhoff, Karsten
2006-03-14
define model demand as German demand net of CHP, run off river hydro, expected wind generation and international power exchange. Hourly wind forecasts and realisations are provided by ISET e.V. Generation plant data are taken from EWI’s plant data base... one model region and endogenously determine international power exchange. In addition, the model is directly applicable to many other empirical questions, such as the effect of CO2emission costs on plant dispatch and costs or competitive bench...
Whetton, P.H.; Pittock, A.B.; Haylock, M.R. ); Rayner, P.J. )
1994-03-01
To assist in estimating likely future climate change in the Australian region, the authors examine the results of four different general circulation modeling experiments run to assess the equilibrium impact of doubling greenhouse gases. The results examined were the most recent available at the time of study from various research centers in North America and Europe, as well as those of the Commonwealth Scientific and Industrial Research Organisation (CSIRO). The approach used is, first, to assess the quality of the control (1 x CO[sub 2]) simulations from each of the models of mean sea level (MSL) pressure and precipitation in the Australian region by comparing these with the corresponding observed patterns; and, second, to then analyze the 2 x CO[sub 2] results of only those model experiments with the best control simulations. Of the models examined two are chosen on the basis of their simulation of current climate in the region: the CSIRO four-level model (CSIRO4) and the United Kingdom Meteorological Office (UKMO) model. For conditions of equivalent doubling of CO[sub 2], both models show substantial increases in surface air temperature of around 4[degrees]-6[degrees] inland and 2[degrees]-4[degrees]C in coastal regions. Both models show decreased MSL pressure over the Australian continent and increases in rainfall over northern, central, and eastern Australia, particularly in the summer half of the year. The CSIRO4 model, but not the UKMO model, also shows increased pressure to the south of the continent and decreased winter rainfall in southwest and southern Australia. Generally, field significance tests show the pattern and magnitude of the changes to be significant of CSIRO4 (for which the necessary monthly simulated data were available). 42 refs., 20 figs., 5 tabs.
Exact solution of the van der Waals model in the critical region
Adriano Barra; Antonio Moro
2015-05-01
The celebrated van der Waals model describes simple fluids in the thermodynamic limit and predicts the existence of a critical point associated to the gas-liquid phase transition. However the behaviour of critical isotherms according to the equation of state, where a gas-liquid phase transition occurs, significantly departs from experimental observations. The correct critical isotherms are heuristically re-established via the Maxwell equal areas rule. A long standing open problem in mean field theory is concerned with the analytic description of van der Waals isotherms for a finite size system that is consistent, in the thermodynamic limit, with the Maxwell prescription. Inspired by the theory of nonlinear conservation laws, we propose a novel mean field approach, based on statistical mechanics, that allows to calculate the van der Waals partition function for a system of large but finite number of particles $N$. Our partition function naturally extends to the whole space of thermodynamic variables, reproduces, in the thermodynamic limit $N\\to \\infty$, the classical results outside the critical region and automatically encodes Maxwell's prescription. We show that isothermal curves evolve in the space of thermodynamic variables like nonlinear breaking waves and the criticality is explained as the mechanism of formation of a classical hydrodynamic shock.
Hagos, Samson M.; Feng, Zhe; McFarlane, Sally A.; Leung, Lai-Yung R.
2013-08-01
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.
Bass, Steffen A.
-ion collisions? · Introduction: the basics of kinetic theory · Examples of transport models and their application-equilibrium QGP and hydrodynamic expansion hadronization hadronic phase and freeze-out · rigorous calculation and data Transport-Theory: · only observe the final state · rely on QGP signatures predicted by Theory
Dynamics of Cell Shape and Forces on Micropatterned Substrates Predicted by a Cellular Potts Model
Philipp J. Albert; Ulrich S. Schwarz
2014-05-19
Micropatterned substrates are often used to standardize cell experiments and to quantitatively study the relation between cell shape and function. Moreover, they are increasingly used in combination with traction force microscopy on soft elastic substrates. To predict the dynamics and steady states of cell shape and forces without any a priori knowledge of how the cell will spread on a given micropattern, here we extend earlier formulations of the two-dimensional cellular Potts model. The third dimension is treated as an area reservoir for spreading. To account for local contour reinforcement by peripheral bundles, we augment the cellular Potts model by elements of the tension-elasticity model. We first parameterize our model and show that it accounts for momentum conservation. We then demonstrate that it is in good agreement with experimental data for shape, spreading dynamics, and traction force patterns of cells on micropatterned substrates. We finally predict shapes and forces for micropatterns that have not yet been experimentally studied.
Effects of CDTT model on the dynamical instability of cylindrically symmetric collapsing stars
Kausar, Hafiza Rizwana, E-mail: rizwa_math@yahoo.com [Centre for Applicable Mathematics and Statistics, UCP Business School, University of Central Punjab, Johar Town, Lahore (Pakistan)
2013-01-01
We assume cylindrically symmetric stars which begin collapsing by dissipating energy in the form of heat flux. We wish to study the effects of Carroll-Duvvuri-Trodden-Turner (CDTT) model, f(R) = R+??{sup 4}/R, on the range of dynamical instability. For this purpose, perturbation scheme is applied to all the metric functions, material functions and f(R) model to obtain the full set of dynamical equation which control the evolution of the physical variables at the surface of a star. It is found that instability limit involves adiabatic index ? which depends on the density profile and immense terms of perturbed CDTT model. In addition, model is constrained by some requirement, e.g. positivity of physical quantities. We also reduce our results asymptotically as ??0, being the GR results in both the Newtonian and post Newtonian regimes.
A Dynamic Network Economic Model of a Service-Oriented Internet with Price and
Nagurney, Anna
Nagurney Department of Operations and Information Management, Isenberg School of Management, Uni- versity-mail: dongl@som.umass.edu Sara Saberi Department of Operations and Information Management, Isenberg SchoolA Dynamic Network Economic Model of a Service-Oriented Internet with Price and Quality Competition
Dynamic model failure tests of dam structures Dalian University of Technology, Dalian 116024, China
Spencer Jr., Billie F.
index for the safety assessment of concrete dams and is predicted through dynamic model failure tests INTRODUCTION A great number of high dams will be built in highly seismic areas, the safety evaluation 116024, China ABSTRACT: For the earthquake safety evaluation of dam structures, it is desirable to extend
A Dynamical Systems Analysis of the Data Assimilation Linked Ecosystem Carbon (DALEC) Models
Skeldon, Anne C.
A Dynamical Systems Analysis of the Data Assimilation Linked Ecosystem Carbon (DALEC) Models Anna M make it ever more important to understand the processes involved in Earth systems, such as the carbon with it the ability to perform ever- more detailed studies of the Earth system and its components. Such studies help
Steady-State and Dynamic Modeling of Commercial Slurry High-Density Polyethylene (HDPE) Processes
Liu, Y. A.
, solvent, and oligomeric species from the polymer. Sol- vent is separated from the oligomer and recycled, Polymers Plus and Aspen Dynamics. The discussion includes thermodynamic properties, phase equilibrium, reaction kinetics, polymer properties, and other modeling issues. We characterize a Ziegler- Natta catalyst
Minimizing the Electricity Bill of Cooperative Users under a Quasi-Dynamic Pricing Model
Pedram, Massoud
advocating that "residential electricity prices must be based on time of use" to fully enable smart gridMinimizing the Electricity Bill of Cooperative Users under a Quasi-Dynamic Pricing Model Safar Hatami and Massoud Pedram University of Southern California Department of Electrical Engineering
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
A Real-Time Reliability Model for Ontology-Based Dynamic Web Service Composition
Xu, Haiping
153 A Real-Time Reliability Model for Ontology-Based Dynamic Web Service Composition Harmeet Chawla--Ontology-based web service composition allows for integration of available web services in real-time to meet desired objectives. In order to evaluate the quality of composite web services at runtime, there is a pressing need
A low-dimensional dynamic model of severe slugging for control design and analysis
Skogestad, Sigurd
. The prerequisites for this to occur are relatively low pipeline pressure and flow rates. Gravity induced slugs the topside (or wellhead) choke valve. However, the increased pressure drop will lower oil recoveryA low-dimensional dynamic model of severe slugging for control design and analysis Espen Storkaas
Simplified dynamic models for control of riser slugging in offshore oil production
Skogestad, Sigurd
especially for fields where the reservoir pressure is relatively low. Therefore, a solution that guaranteesForReview Only Simplified dynamic models for control of riser slugging in offshore oil production Journal: Oil and Gas Facilities Manuscript ID: Draft Manuscript Type: Technical Paper Date Submitted
Modeling and Dynamic Management of 3D Multicore Systems with Liquid Cooling
Simunic, Tajana
Modeling and Dynamic Management of 3D Multicore Systems with Liquid Cooling Ayse K. Coskun , Jos liquid cooling. Furthermore, for systems capable of varying the coolant flow rate at runtime, our University of Madrid, Spain. Embedded Systems Laboratory (ESL), Ecole Polytechnique FÂ´edÂ´erale de Lausanne
Sukhatme, Gaurav S.
Helicopter Srikanth Saripalli and Gaurav S. Sukhatme Robotics Embedded Systems Laboratory Department,gaurav}@robotics.usc.edu Abstract We propose the use of a model helicopter to emulate the landing dynamics of a spacecraft. Our controller accepts thruster inputs (like those on a spacecraft) and converts them into appropriate helicopter
Planning and Control of Electric Vehicles Using Dynamic Energy Capacity Models
Zhang, Wei
for a large population of Plug-in Electric Vehicles (PEVs) for demand response applications. We consider both costs. I. INTRODUCTION The number of Plug-in Electric Vehicles (PEVs) is ex- pected to be more than onePlanning and Control of Electric Vehicles Using Dynamic Energy Capacity Models Jianzhe Liu*, Sen Li
A Kernel-Based Spatio-Temporal Dynamical Model for Nowcasting Weather Radar Reflectivities
A Kernel-Based Spatio-Temporal Dynamical Model for Nowcasting Weather Radar Reflectivities Ke Xu of the technique and its potential for nowcasting weather radar reflectivities. Key Words: Bayesian, dilation to nowcasting weather radar reflectivities into two general categories. The first is the use of simple
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
Modelling dynamics of piezoelectric solids in the two-dimensional case
Melnik, Roderick
that may not be attained by purely electronic means. These new horizons of piezoelectric applicationsModelling dynamics of piezoelectric solids in the two-dimensional case R.V.N. Melnik a,*, K; Hollow piezoceramic cylinders; Corner points; Accuracy estimates 1. Introduction In many applications
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
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
A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness
O'Leary, Michael
A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness Mike O'Leary Department of Mathematics Towson University World Conference on Nonlinear Analysis Orlando, FL July 2008 Mike O'Leary of this work are joint with Judith Miller, Georgetown University. Mike O'Leary (Towson University) A Diffusion
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 Simple Stand Growth Model Based on Canopy Dynamics and Biomechanics
Cao, Quang V.
A Simple Stand Growth Model Based on Canopy Dynamics and Biomechanics Thomas J. Dean, Mauricio be expressed in terms of wind drag. From this point of view, biomechanical principles determine the stem cross in a developing stand, biomechanics create a conceptual framework for predicting aboveground stem production
PhD Position Available: integrative biomechanics, computational modeling, nonlinear dynamics
Clewley, Robert
PhD Position Available: integrative biomechanics, computational modeling, nonlinear dynamics and mathematical analysis of biomechanical and neural control systems. We are looking for an excellent and highly.edu/~biodhe/#Research). These are being used to study the Crayfish swim escape mechanism as a case study in integrative biomechanical
Simulation of exhaust gas pollution within an eventdriven multimodal dynamic traffic model
Toint, Philippe
. The second is the temporal evolution of the pollution level, both globally and at the scale of specific city1 Simulation of exhaust gas pollution within an eventdriven multimodal dynamic traffic model E development of the last decade, and the quality of life in cities is part of these emerging and widely spread
Perovskite Quantum Dots Modeled Using ab Initio and Replica Exchange Molecular Dynamics
Sargent, Edward H. "Ted"
Perovskite Quantum Dots Modeled Using ab Initio and Replica Exchange Molecular Dynamics Andrei Buin halide perovskites have recently attracted tremen- dous attention at both the experimental. Here we investigate perovskite quantum dots from theory, predicting an upper bound of the Bohr radius
DYNAMIC MODEL OF AN INDUSTRIAL HEAT PUMP USING WATER AS REFRIGERANT
Paris-Sud XI, Université de
1 DYNAMIC MODEL OF AN INDUSTRIAL HEAT PUMP USING WATER AS REFRIGERANT CHAMOUN MARWAN to improve industrial energy efficiency, the development of a high temperature heat pump using water vapor as refrigerant is investigated. Technical problems restraining the feasibility of this industrial heat pump
Combining Multiple Dynamic Models and Deep Learning Architectures for Tracking the
Carneiro, Gustavo
1 Combining Multiple Dynamic Models and Deep Learning Architectures for Tracking the Left Ventricle such that the expected segmentation of the current time step is estimated based on the appearance, shape, and motion Classifiers. This work was supported by project the FCT (ISR/IST plurianual funding) through the PIDDAC
Energy-Aware Modeling and Scheduling of Real-Time Tasks for Dynamic Voltage Scaling
Xu, Cheng-Zhong
scaling (DVS) is an effective approach to power reduction by scaling the processor voltage and frequency the voltage accordingly. On the other hand, a reduction of the operating frequency leads to an increaseEnergy-Aware Modeling and Scheduling of Real-Time Tasks for Dynamic Voltage Scaling Xiliang Zhong
Inferred Models for Dynamic and Sparse Hardware-Software Spaces Weidan Wu Benjamin C. Lee
Lee, Benjamin C.
Inferred Models for Dynamic and Sparse Hardware-Software Spaces Weidan Wu Benjamin C. Lee Duke University {weidan.wu, benjamin.c.lee}@duke.edu Abstract Diverse software and heterogeneous hardware pose new hardware-software analysis. These strategies include (i) identifying shared software behavior; (ii
Modelling Shale Gas Flow Using the Concept of Dynamic Apparent Permeability
Farid, Syed Munib Ullah
2015-05-12
The basic idea behind this research is to propose a work flow to model gas flow in numerical simulators, which would take into consideration all the complexities of the multiple porosity systems that exist in shale matrix and the different dynamics...
Coastal Dynamics 2013 MODELING OF THE TOHOKU-OKI 2011 TSUNAMI GENERATION, FAR-FIELD AND
Kirby, James T.
Coastal Dynamics 2013 Paper No. MODELING OF THE TOHOKU-OKI 2011 TSUNAMI GENERATION, FAR Tsunami hazard assessment for future megathrust earthquakes requires that we understand the source mechanisms and tsunami generation processes for large historical events, such as the devastating Tohoku
Filtering Noisy ECG Signals Using the Extended Kalman Filter Based on a Modified Dynamic ECG Model
Paris-Sud XI, Université de
of biomedical signal processing. Specifically, the extraction of ECG signals from low SNR measurementsFiltering Noisy ECG Signals Using the Extended Kalman Filter Based on a Modified Dynamic ECG Model University of Technology, Tehran, Iran 2 Images and Signals Laboratory, Institut National Polytechnique de
FLUID DYNAMICAL AND MODELING ISSUES OF CHEMICAL FLOODING FOR ENHANCED OIL RECOVERY
Daripa, Prabir
of the objective functions in tertiary oil recovery by polymer flooding is the "op- timal" viscous profileFLUID DYNAMICAL AND MODELING ISSUES OF CHEMICAL FLOODING FOR ENHANCED OIL RECOVERY Prabir Daripa are succinctly summarized including characteri- zation of the optimal flooding scheme that leads to maximum oil
A Probabilistic Model for the Dynamics of Cascading Failures and Blackouts in Power Grids
Hayat, Majeed M.
cause failures of power system components such as transmission lines and generators, which, in turn, may1 A Probabilistic Model for the Dynamics of Cascading Failures and Blackouts in Power Grids Mahshid Abstract--Current power grids suffer periodic disturbances that may trigger cascades of component failures
A continuum model for defect dynamics in metallic glasses Amit Acharya
Acharya, Amit
a fundamental characterization of the process of plastic deformation in a metallic glass, relating its structure and the simplest linear kinetic assumptions arising from enforcing the second law of thermodynamics mechanical model of defect dynamics in metallic glasses that accounts for topological, energetic, and kinetic
Dynamic Model and Control of a New Quadrotor Unmanned Aerial Vehicle with Tilt-Wing
Yanikoglu, Berrin
Dynamic Model and Control of a New Quadrotor Unmanned Aerial Vehicle with Tilt-Wing Mechanism Kaan, LQR, Quadrotor, Tilt-wing, VTOL. I. INTRODUCTION Unmanned aerial vehicles (UAV) designed for various of a new tilt-wing aerial vehicle (SUAVi: Sabanci University Unmanned Aerial Vehicle) that is capable
Technical Note Comparing Dynamic Causal Models using AIC, BIC and Free Energy
Penny, Will
Technical Note Comparing Dynamic Causal Models using AIC, BIC and Free Energy W.D. Penny Wellcome (Hoeting et al., 1999), signal processing (Penny and Roberts, 2002), machine learning (Beal and Ghahramani, 2003), and neuroimaging (Friston et al., 2008; Penny et al., 2003; Trujillo-Barreto et al., 2004
A non-stationary model for simulating the dynamics of ocular aberrations
Dainty, Chris
Signal Processing and Signal Modeling (Wiley Series in Telecommunications and Signal Processing, 2001). 2 of aberration components in the human eye," In IEEE Signal Process. Workshop Statist. pages 241-244 (2001). 12 and retinal image quality due to tear film dynamics," Opt. Express 14, 12552-12559 (2006). 18. L. Rankine, N
Extraction and Interpretation of gamma N --> Delta Form Factors within a Dynamical Model
B. Julia-Diaz; T. -S. H. Lee; T. Sato; L. C. Smith
2006-12-15
Within the dynamical model of Refs. [Phys. Rev. C54, 2660 (1996); C63, 055201 (2001)], we perform an analysis of recent data of pion electroproduction reactions at energies near the Delta(1232) resonance. We discuss possible interpretations of the extracted bare and dressed gamma N --> Delta form factors in terms of relativistic constituent quark models and Lattice QCD calculations. Possible future developments are discussed.
Overview of the synergia 3-D multi-particle dynamics modeling framework
Spentzouris, P.; Amundson, J.F.; Dechow, D.R.; /Tech-X, Boulder
2005-05-01
High precision modeling of space-charge effects is essential for designing future accelerators as well as optimizing the performance of existing machines. Synergia is a high-fidelity parallel beam dynamics simulation package with fully three dimensional space-charge capabilities and a higher-order optics implementation. We describe the Synergia framework and model benchmarks we obtained by comparing to semi-analytic results and other codes. We also present Synergia simulations of the Fermilab Booster accelerator and comparisons with experiment.