X. Frank Xu
2010-03-30T23:59:59.000Z
Multiscale modeling of stochastic systems, or uncertainty quantization of multiscale modeling is becoming an emerging research frontier, with rapidly growing engineering applications in nanotechnology, biotechnology, advanced materials, and geo-systems, etc. While tremendous efforts have been devoted to either stochastic methods or multiscale methods, little combined work had been done on integration of multiscale and stochastic methods, and there was no method formally available to tackle multiscale problems involving uncertainties. By developing an innovative Multiscale Stochastic Finite Element Method (MSFEM), this research has made a ground-breaking contribution to the emerging field of Multiscale Stochastic Modeling (MSM) (Fig 1). The theory of MSFEM basically decomposes a boundary value problem of random microstructure into a slow scale deterministic problem and a fast scale stochastic one. The slow scale problem corresponds to common engineering modeling practices where fine-scale microstructure is approximated by certain effective constitutive constants, which can be solved by using standard numerical solvers. The fast scale problem evaluates fluctuations of local quantities due to random microstructure, which is important for scale-coupling systems and particularly those involving failure mechanisms. The Green-function-based fast-scale solver developed in this research overcomes the curse-of-dimensionality commonly met in conventional approaches, by proposing a random field-based orthogonal expansion approach. The MSFEM formulated in this project paves the way to deliver the first computational tool/software on uncertainty quantification of multiscale systems. The applications of MSFEM on engineering problems will directly enhance our modeling capability on materials science (composite materials, nanostructures), geophysics (porous media, earthquake), biological systems (biological tissues, bones, protein folding). Continuous development of MSFEM will further contribute to the establishment of Multiscale Stochastic Modeling strategy, and thereby potentially to bring paradigm-shifting changes to simulation and modeling of complex systems cutting across multidisciplinary fields.
Multiscale Modeling of Hematologic Disorders
Fedosov, Dmitry A.; Pivkin, Igor; Pan, Wenxiao; Dao, Ming; Caswell, Bruce; Karniadakis, George E.
2012-01-28T23:59:59.000Z
Parasitic infectious diseases and other hereditary hematologic disorders are often associated with major changes in the shape and viscoelastic properties of red blood cells (RBCs). Such changes can disrupt blood flow and even brain perfusion, as in the case of cerebral malaria. Modeling of these hematologic disorders requires a seamless multiscale approach, where blood cells and blood flow in the entire arterial tree are represented accurately using physiologically consistent parameters. In this chapter, we present a computational methodology based on dissipative particle dynamics (DPD) which models RBCs as well as whole blood in health and disease. DPD is a Lagrangian method that can be derived from systematic coarse-graining of molecular dynamics but can scale efficiently up to small arteries and can also be used to model RBCs down to spectrin level. To this end, we present two complementary mathematical models for RBCs and describe a systematic procedure on extracting the relevant input parameters from optical tweezers and microfluidic experiments for single RBCs. We then use these validated RBC models to predict the behavior of whole healthy blood and compare with experimental results. The same procedure is applied to modeling malaria, and results for infected single RBCs and whole blood are presented.
Multiscale modeling of spatially variable water and energy balance processes
Famiglietti, JS; Wood, EF
1994-01-01T23:59:59.000Z
MULTISCALE WATER AND ENERGY BALANCE MODELING Wood, E. F. ,MULTISCALE WATER AND ENERGY BALANCE MODELING cess runoff,models of water and energy balance, Ph.D. dissertation,
Multiscale model reduction for shale gas transport in fractured media
Akkutlu, I Y; Vasilyeva, Maria
2015-01-01T23:59:59.000Z
In this paper, we develop a multiscale model reduction technique that describes shale gas transport in fractured media. Due to the pore-scale heterogeneities and processes, we use upscaled models to describe the matrix. We follow our previous work \\cite{aes14}, where we derived an upscaled model in the form of generalized nonlinear diffusion model to describe the effects of kerogen. To model the interaction between the matrix and the fractures, we use Generalized Multiscale Finite Element Method. In this approach, the matrix and the fracture interaction is modeled via local multiscale basis functions. We developed the GMsFEM and applied for linear flows with horizontal or vertical fracture orientations on a Cartesian fine grid. In this paper, we consider arbitrary fracture orientations and use triangular fine grid and developed GMsFEM for nonlinear flows. Moreover, we develop online basis function strategies to adaptively improve the convergence. The number of multiscale basis functions in each coarse region ...
Jiang, Lijian
2009-05-15T23:59:59.000Z
porous media, oil reservoir simulations and subsurface characterization. In the work, we investigate three main multiscale numerical methods, i.e., multiscale finite element method, partition of unity method and mixed multiscale finite element method...
Institute for Multiscale Modeling of Biological Interactions
Paulaitis, Michael E; Garcia-Moreno, Bertrand; Lenhoff, Abraham
2009-12-26T23:59:59.000Z
The Institute for Multiscale Modeling of Biological Interactions (IMMBI) has two primary goals: Foster interdisciplinary collaborations among faculty and their research laboratories that will lead to novel applications of multiscale simulation and modeling methods in the biological sciences and engineering; and Building on the unique biophysical/biology-based engineering foundations of the participating faculty, train scientists and engineers to apply computational methods that collectively span multiple time and length scales of biological organization. The success of IMMBI will be defined by the following: Size and quality of the applicant pool for pre-doctoral and post-doctoral fellows; Academic performance; Quality of the pre-doctoral and post-doctoral research; Impact of the research broadly and to the DOE (ASCR program) mission; Distinction of the next career step for pre-doctoral and post-doctoral fellows; and Faculty collaborations that result from IMMBI activities. Specific details about accomplishments during the three years of DOE support for IMMBI have been documented in Annual Progress Reports (April 2005, June 2006, and March 2007) and a Report for a National Academy of Sciences Review (October 2005) that were submitted to DOE on the dates indicated. An overview of these accomplishments is provided.
Stochastic multiscale models for fracture analysis of functionally graded materials
Rahman, Sharif
Chakraborty, Sharif Rahman * Department of Mechanical and Industrial Engineering, College of Engineering three multiscale models, including sequential, invasive, and concurrent models, for fracture analysis-intensity factors or accurate probability of fracture initiation. The concurrent multiscale model is sufficiently
Stochastic realization theory for exact and approximate multiscale models
Tucker, Dewey S. (Dewey Stanton)
2005-01-01T23:59:59.000Z
The thesis provides a detailed analysis of the independence structure possessed by multiscale models and demonstrates that such an analysis provides important insight into the multiscale stochastic realization problem. ...
Final Report for Integrated Multiscale Modeling of Molecular Computing Devices
Glotzer, Sharon C.
2013-08-28T23:59:59.000Z
In collaboration with researchers at Vanderbilt University, North Carolina State University, Princeton and Oakridge National Laboratory we developed multiscale modeling and simulation methods capable of modeling the synthesis, assembly, and operation of molecular electronics devices. Our role in this project included the development of coarse-grained molecular and mesoscale models and simulation methods capable of simulating the assembly of millions of organic conducting molecules and other molecular components into nanowires, crossbars, and other organized patterns.
Multiscale modeling of spatially variable water and energy balance processes
Famiglietti, J. S; Wood, E. F
1994-01-01T23:59:59.000Z
MULTISCALE WATER AND ENERGY BALANCE MODELING Wood, E. F. ,spatially variable water and energy balance processes J. S.modeling. Water and energy balance models are developed at
Multiscale modeling of spatially variable water and energy balance processes
Famiglietti, JS; Wood, EF
1994-01-01T23:59:59.000Z
AND WOOD: MULTISCALE WATER AND ENERGY BALANCE MODELING Wood,of spatially variable water and energy balance processes J.hydrological modeling. Water and energy balance models are
Multiscale Modeling of Radiation Damage in
Multiscale Modeling of Radiation Damage in Fusion Reactor Materials Brian D. Wirth, R.J. Kurtz-7405-Eng-48. #12;Presentation overview · Introduction to fusion reactor materials and radiation damage. tailor He HFIR isotopic tailor He HFIR target/RB He appmHe displacement damage (dpa) ffuussiioonn
Multiscale numerical methods for some types of parabolic equations
Nam, Dukjin
2009-05-15T23:59:59.000Z
method. The goal of the second problem is to develop efficient multiscale numerical techniques for solving turbulent diffusion equations governed by celluar flows. The solution near the separatrices can be approximated by the solution of a system of one...
Application of multiscale water and energy balance models on a tallgrass prairie
Famiglietti, J. S; Wood, E. F
1994-01-01T23:59:59.000Z
Application of multiscale water and energy balance models onAPPLICATION OF MULTISCALE WATER AND ENERGY BALANCE MODELSand macroscale models of water and energy balance, Ph.D.
Moist multi-scale models for the hurricane embryo
Majda, Andrew J. [New York University; Xing, Yulong [ORNL; Mohammadian, Majid [University of Ottawa, Canada
2010-01-01T23:59:59.000Z
Determining the finite-amplitude preconditioned states in the hurricane embryo, which lead to tropical cyclogenesis, is a central issue in contemporary meteorology. In the embryo there is competition between different preconditioning mechanisms involving hydrodynamics and moist thermodynamics, which can lead to cyclogenesis. Here systematic asymptotic methods from applied mathematics are utilized to develop new simplified moist multi-scale models starting from the moist anelastic equations. Three interesting multi-scale models emerge in the analysis. The balanced mesoscale vortex (BMV) dynamics and the microscale balanced hot tower (BHT) dynamics involve simplified balanced equations without gravity waves for vertical vorticity amplification due to moist heat sources and incorporate nonlinear advective fluxes across scales. The BMV model is the central one for tropical cyclogenesis in the embryo. The moist mesoscale wave (MMW) dynamics involves simplified equations for mesoscale moisture fluctuations, as well as linear hydrostatic waves driven by heat sources from moisture and eddy flux divergences. A simplified cloud physics model for deep convection is introduced here and used to study moist axisymmetric plumes in the BHT model. A simple application in periodic geometry involving the effects of mesoscale vertical shear and moist microscale hot towers on vortex amplification is developed here to illustrate features of the coupled multi-scale models. These results illustrate the use of these models in isolating key mechanisms in the embryo in a simplified content.
Deymier, Pierre
technique for coupling disparate simula- tion methods that address the same process, albeit at differentDynamic compound wavelet matrix method for multiphysics and multiscale problems Krishna February 2008 The paper presents the dynamic compound wavelet method dCWM for modeling the time evolution
A multilevel multiscale mimetic method for an anisotropic infiltration problem
Lipnikov, Konstantin [Los Alamos National Laboratory; Moulton, David [Los Alamos National Laboratory; Svyatskiy, Daniil [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
Modeling of multiphase flow and transport in highly heterogeneous porous media must capture a broad range of coupled spatial and temporal scales. Recently, a hierarchical approach dubbed the Multilevel Multiscale Mimetic (M3) method, was developed to simulate two-phase flow in porous media. The M{sup 3} method is locally mass conserving at all levels in its hierarchy, it supports unstructured polygonal grids and full tensor permeabilities, and it can achieve large coarsening factors. In this work we consider infiltration of water into a two-dimensional layered medium. The grid is aligned with the layers but not the coordinate axes. We demonstrate that with an efficient temporal updating strategy for the coarsening parameters, fine-scale accuracy of prominent features in the flow is maintained by the M{sup 3} method.
MULTISCALE MODELING OF SOLIDIFICATION OF MULTI-COMPONENT ALLOYS
Zabaras, Nicholas J.
MULTISCALE MODELING OF SOLIDIFICATION OF MULTI-COMPONENT ALLOYS A Dissertation Presented;MULTISCALE MODELING OF SOLIDIFICATION OF MULTI-COMPONENT ALLOYS Lijian Tan, Ph.D. Cornell University 2007-dimensional dendrite growth of pure material and alloys, eutectic and peritectic solidification, convection effects
A Multiscale Method for Fast Capacitance Extraction Johannes Tausch
Tausch, Johannes
A Multiscale Method for Fast Capacitance Extraction Johannes Tausch Dept. of Mathematics Southern boundary-element method, like the well- known FASTCAP program, but instead of using an adaptive fast method can be applied to complicated geometries, generates a sparser boundary-element matrix than
Multiscale modeling in granular flow
Rycroft, Christopher Harley
2007-01-01T23:59:59.000Z
Granular materials are common in everyday experience, but have long-resisted a complete theoretical description. Here, we consider the regime of slow, dense granular flow, for which there is no general model, representing ...
Multiscale molecular dynamics using the matched interface and boundary method
Geng Weihua [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States); Wei, G.W., E-mail: wei@math.msu.ed [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States); Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824 (United States)
2011-01-20T23:59:59.000Z
The Poisson-Boltzmann (PB) equation is an established multiscale model for electrostatic analysis of biomolecules and other dielectric systems. PB based molecular dynamics (MD) approach has a potential to tackle large biological systems. Obstacles that hinder the current development of PB based MD methods are concerns in accuracy, stability, efficiency and reliability. The presence of complex solvent-solute interface, geometric singularities and charge singularities leads to challenges in the numerical solution of the PB equation and electrostatic force evaluation in PB based MD methods. Recently, the matched interface and boundary (MIB) method has been utilized to develop the first second order accurate PB solver that is numerically stable in dealing with discontinuous dielectric coefficients, complex geometric singularities and singular source charges. The present work develops the PB based MD approach using the MIB method. New formulation of electrostatic forces is derived to allow the use of sharp molecular surfaces. Accurate reaction field forces are obtained by directly differentiating the electrostatic potential. Dielectric boundary forces are evaluated at the solvent-solute interface using an accurate Cartesian-grid surface integration method. The electrostatic forces located at reentrant surfaces are appropriately assigned to related atoms. Extensive numerical tests are carried out to validate the accuracy and stability of the present electrostatic force calculation. The new PB based MD method is implemented in conjunction with the AMBER package. MIB based MD simulations of biomolecules are demonstrated via a few example systems.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gao, Kai; Fu, Shubin; Gibson, Richard L.; Chung, Eric T.; Efendiev, Yalchin
2015-04-14T23:59:59.000Z
It is important to develop fast yet accurate numerical methods for seismic wave propagation to characterize complex geological structures and oil and gas reservoirs. However, the computational cost of conventional numerical modeling methods, such as finite-difference method and finite-element method, becomes prohibitively expensive when applied to very large models. We propose a Generalized Multiscale Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both the boundaries and interior of a coarse node support or coarse element. The application of multiscale basis functions can capture the fine scale mediummore »property variations, and allows us to greatly reduce the degrees of freedom that are required to implement the modeling compared with conventional finite-element method for wave equation, while restricting the error to low values. We formulate the continuous Galerkin and discontinuous Galerkin formulation of the multiscale method, both of which have pros and cons. Applications of the multiscale method to three heterogeneous models show that our multiscale method can effectively model the elastic wave propagation in anisotropic media with a significant reduction in the degrees of freedom in the modeling system.« less
Multiscale Computational Modeling of Multiphase Composites with Damage
Cheng, Feifei
2013-11-01T23:59:59.000Z
A multiscale computational framework for multiphase composites considering damage is developed in this research. In micro-scale, micromechanics based homogenization methods are used to estimate effective elastic moduli ...
Gao, Kai; Gibson, Richard L; Chung, Eric T; Efendiev, Yalchin
2014-01-01T23:59:59.000Z
It is important to develop fast yet accurate numerical methods for seismic wave propagation to characterize complex geological structures and oil and gas reservoirs. However, the computational cost of conventional numerical modeling methods, such as finite-difference method and finite-element method, becomes prohibitively expensive when applied to very large models. We propose a Generalized Multiscale Generalized Multiscale Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both boundaries and the interior of a coarse node support or coarse element. The application of multiscale basis functions can capture the fine scale medium property variations, and allows us to greatly reduce the degrees of freedom that are required to implement the modeling compared with conventional finite-element method for wave equation, while restricting the error to low values. We formulate the continuous Galerkin and di...
Application of multiscale water and energy balance models on a tallgrass prairie
Famiglietti, J. S; Wood, E. F
1994-01-01T23:59:59.000Z
of multiscale water and energy balance models on a tallgrassOF MULTISCALE WATER AND ENERGY BALANCE MODELS I •l I •. [models of water and energy balance, Ph.D. dissertation,
Multi-Scale Jacobi Method for Anderson Localization
John Z. Imbrie
2014-07-03T23:59:59.000Z
A new KAM-style proof of Anderson localization is obtained. A sequence of local rotations is defined, such that off-diagonal matrix elements of the Hamiltonian are driven rapidly to zero. This leads to the first proof via multi-scale analysis of exponential decay of the eigenfunction correlator (this implies strong dynamical localization). The method has been used in recent work on many-body localization [arXiv:1403.7837].
Multiscale modeling of polyisoprene on graphite
Pandey, Yogendra Narayan; Brayton, Alexander; Doxastakis, Manolis, E-mail: edoxastakis@uh.edu [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204 (United States)] [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204 (United States); Burkhart, Craig; Papakonstantopoulos, George J. [Global Materials Science Division, The Goodyear Tire and Rubber Company, Akron, Ohio 44305 (United States)] [Global Materials Science Division, The Goodyear Tire and Rubber Company, Akron, Ohio 44305 (United States)
2014-02-07T23:59:59.000Z
The local dynamics and the conformational properties of polyisoprene next to a smooth graphite surface constructed by graphene layers are studied by a multiscale methodology. First, fully atomistic molecular dynamics simulations of oligomers next to the surface are performed. Subsequently, Monte Carlo simulations of a systematically derived coarse-grained model generate numerous uncorrelated structures for polymer systems. A new reverse backmapping strategy is presented that reintroduces atomistic detail. Finally, multiple extensive fully atomistic simulations with large systems of long macromolecules are employed to examine local dynamics in proximity to graphite. Polyisoprene repeat units arrange close to a parallel configuration with chains exhibiting a distribution of contact lengths. Efficient Monte Carlo algorithms with the coarse-grain model are capable of sampling these distributions for any molecular weight in quantitative agreement with predictions from atomistic models. Furthermore, molecular dynamics simulations with well-equilibrated systems at all length-scales support an increased dynamic heterogeneity that is emerging from both intermolecular interactions with the flat surface and intramolecular cooperativity. This study provides a detailed comprehensive picture of polyisoprene on a flat surface and consists of an effort to characterize such systems in atomistic detail.
Fast multiscale Gaussian beam methods for wave equations in bounded convex domains
Bao, Gang, E-mail: bao@math.msu.edu [Department of Mathematics, Zhejiang University, Hangzhou 310027 (China) [Department of Mathematics, Zhejiang University, Hangzhou 310027 (China); Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States); Lai, Jun, E-mail: laijun@msu.edu [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States)] [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States); Qian, Jianliang, E-mail: qian@math.msu.edu [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States)] [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States)
2014-03-15T23:59:59.000Z
Motivated by fast multiscale Gaussian wavepacket transforms and multiscale Gaussian beam methods which were originally designed for pure initial-value problems of wave equations, we develop fast multiscale Gaussian beam methods for initial boundary value problems of wave equations in bounded convex domains in the high frequency regime. To compute the wave propagation in bounded convex domains, we have to take into account reflecting multiscale Gaussian beams, which are accomplished by enforcing reflecting boundary conditions during beam propagation and carrying out suitable reflecting beam summation. To propagate multiscale beams efficiently, we prove that the ratio of the squared magnitude of beam amplitude and the beam width is roughly conserved, and accordingly we propose an effective indicator to identify significant beams. We also prove that the resulting multiscale Gaussian beam methods converge asymptotically. Numerical examples demonstrate the accuracy and efficiency of the method.
Multiscale modeling of alloy solidification using a database approach
Zabaras, Nicholas J.
Multiscale modeling of alloy solidification using a database approach Lijian Tan, Nicholas Zabaras-scale model based on a database approach is presented to investigate alloy solidification. Appropriate, liquid volume fraction and microstructure features. These assumptions lead to a macroscale model with two
A COMPUTATIONAL METHOD TO EXTRACT MACROSCOPIC VARIABLES AND THEIR DYNAMICS IN MULTISCALE SYSTEMS
Gottwald, Georg A.
A COMPUTATIONAL METHOD TO EXTRACT MACROSCOPIC VARIABLES AND THEIR DYNAMICS IN MULTISCALE SYSTEMS-independent methods for analysing multiscale dy- namical systems using numerical techniques based on the transfer operator and its adjoint. In particular, we present a method for testing whether an arbitrary dynamical
A Generalized Multiscale Finite Element Method for Poroelasticity Problems I: Linear Problems
Brown, Donald L
2015-01-01T23:59:59.000Z
In this paper, we consider the numerical solution of poroelasticity problems that are of Biot type and develop a general algorithm for solving coupled systems. We discuss the challenges associated with mechanics and flow problems in heterogeneous media. The two primary issues being the multiscale nature of the media and the solutions of the fluid and mechanics variables traditionally developed with separate grids and methods. For the numerical solution we develop and implement a Generalized Multiscale Finite Element Method (GMsFEM) that solves problem on a coarse grid by constructing local multiscale basis functions. The procedure begins with construction of multiscale bases for both displacement and pressure in each coarse block. Using a snapshot space and local spectral problems, we construct a basis of reduced dimension. Finally, after multiplying by a multiscale partitions of unity, the multiscale basis is constructed in the offline phase and the coarse grid problem then can be solved for arbitrary forcin...
Regueiro, Richard A.
, hydrofracturing, or oil shale production. Current macro- scale and multiscale models do not account simultaneously
Probabilistic multiscale models and measurements of self-heating
Paris-Sud XI, Université de
1 Probabilistic multiscale models and measurements of self-heating under multiaxial high cycle cyclic loadings, usually referred to as "self-heating tests." This paper focuses on two models whose parameters are tuned by resorting to self-heating tests and then used to predict high cycle fatigue
Identification of a mesoscale model with multiscale experimental observations
Paris-Sud XI, Université de
Identification of a mesoscale model with multiscale experimental observations M.T. Nguyen, C and at mesoscale within the framework of a heterogeneous microstruc- ture which is modeled by a random elastic measurements of the displacement fields at macroscale and at mesoscale performed with only a single specimen
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
Masud, Arif
. There are many processes in nat- ure that can be modeled using the Darcy flow equations. Oil extraction to be solenoidal (i.e., a divergence free vector field). The main issue is that the equations of Darcy flow leadA stabilized mixed finite element method for Darcy flow based on a multiscale decomposition
Mathematical and Numerical Analyses of Peridynamics for Multiscale Materials Modeling
Du, Qiang
2014-11-12T23:59:59.000Z
The rational design of materials, the development of accurate and efficient material simulation algorithms, and the determination of the response of materials to environments and loads occurring in practice all require an understanding of mechanics at disparate spatial and temporal scales. The project addresses mathematical and numerical analyses for material problems for which relevant scales range from those usually treated by molecular dynamics all the way up to those most often treated by classical elasticity. The prevalent approach towards developing a multiscale material model couples two or more well known models, e.g., molecular dynamics and classical elasticity, each of which is useful at a different scale, creating a multiscale multi-model. However, the challenges behind such a coupling are formidable and largely arise because the atomistic and continuum models employ nonlocal and local models of force, respectively. The project focuses on a multiscale analysis of the peridynamics materials model. Peridynamics can be used as a transition between molecular dynamics and classical elasticity so that the difficulties encountered when directly coupling those two models are mitigated. In addition, in some situations, peridynamics can be used all by itself as a material model that accurately and efficiently captures the behavior of materials over a wide range of spatial and temporal scales. Peridynamics is well suited to these purposes because it employs a nonlocal model of force, analogous to that of molecular dynamics; furthermore, at sufficiently large length scales and assuming smooth deformation, peridynamics can be approximated by classical elasticity. The project will extend the emerging mathematical and numerical analysis of peridynamics. One goal is to develop a peridynamics-enabled multiscale multi-model that potentially provides a new and more extensive mathematical basis for coupling classical elasticity and molecular dynamics, thus enabling next generation atomistic-to-continuum multiscale simulations. In addition, a rigorous study of nite element discretizations of peridynamics will be considered. Using the fact that peridynamics is spatially derivative free, we will also characterize the space of admissible peridynamic solutions and carry out systematic analyses of the models, in particular rigorously showing how peridynamics encompasses fracture and other failure phenomena. Additional aspects of the project include the mathematical and numerical analysis of peridynamics applied to stochastic peridynamics models. In summary, the project will make feasible mathematically consistent multiscale models for the analysis and design of advanced materials.
MULTISCALE MODELING OF THE RESPIRATORY TRACT
Maury, Bertrand
that this problem has at least one solution locally in time for any data and, in the special case where the spring: NavierŔStokes equations; local existence; coupling of models; ventilation process; Finite Element Method
Multiscale Subsurface Biogeochemical Modeling Project at NERSC
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports(Journal Article) |govInstrumentsmfrirtA Journey Inside the Complex andFOUR Los Phase 1MillerYi LiuAmericanMoreTowardMultiscale Subsurface
Multiscale modeling of exocytosis in the fertilization process
Aldo Ledesma Duran; I. Santamaria-Holek
2015-02-23T23:59:59.000Z
We discuss the implementation of a multiscale biophysico-chemical model able to cope with the main mechanisms underlying cumulative exocytosis in cells. The model is based on a diffusion equation in the presence of external forces that links calcium signaling and the biochemistry associated to the activity of cytoskeletal-based protein motors. This multiscale model offers an excellent quantitative spatio-temporal description of the cumulative exocytosis measured by means of fluorescence experiments. We also review pre-existing models reported in the literature on calcium waves, protein motor activation and dynamics, and intracellular directed transport of vesicles. As an example of the proposed model, we analyze the formation of the shield against polyspermy in the early events of fertilization in sea urchin eggs.
Fluid simulations with atomistic resolution: a hybrid multiscale method with field-wise coupling
Borg, Matthew K. [Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow G1 1XJ (United Kingdom)] [Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow G1 1XJ (United Kingdom); Lockerby, Duncan A., E-mail: duncan.lockerby@warwick.ac.uk [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Reese, Jason M., E-mail: jason.reese@strath.ac.uk [Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow G1 1XJ (United Kingdom)
2013-12-15T23:59:59.000Z
We present a new hybrid method for simulating dense fluid systems that exhibit multiscale behaviour, in particular, systems in which a Navier–Stokes model may not be valid in parts of the computational domain. We apply molecular dynamics as a local microscopic refinement for correcting the Navier–Stokes constitutive approximation in the bulk of the domain, as well as providing a direct measurement of velocity slip at bounding surfaces. Our hybrid approach differs from existing techniques, such as the heterogeneous multiscale method (HMM), in some fundamental respects. In our method, the individual molecular solvers, which provide information to the macro model, are not coupled with the continuum grid at nodes (i.e. point-wise coupling), instead coupling occurs over distributed heterogeneous fields (here referred to as field-wise coupling). This affords two major advantages. Whereas point-wise coupled HMM is limited to regions of flow that are highly scale-separated in all spatial directions (i.e. where the state of non-equilibrium in the fluid can be adequately described by a single strain tensor and temperature gradient vector), our field-wise coupled HMM has no such limitations and so can be applied to flows with arbitrarily-varying degrees of scale separation (e.g. flow from a large reservoir into a nano-channel). The second major advantage is that the position of molecular elements does not need to be collocated with nodes of the continuum grid, which means that the resolution of the microscopic correction can be adjusted independently of the resolution of the continuum model. This in turn means the computational cost and accuracy of the molecular correction can be independently controlled and optimised. The macroscopic constraints on the individual molecular solvers are artificial body-force distributions, used in conjunction with standard periodicity. We test our hybrid method on the Poiseuille flow problem for both Newtonian (Lennard-Jones) and non-Newtonian (FENE) fluids. The multiscale results are validated with expensive full-scale molecular dynamics simulations of the same case. Very close agreement is obtained for all cases, with as few as two micro elements required to accurately capture both the Newtonian and non-Newtonian flowfields. Our multiscale method converges very quickly (within 3–4 iterations) and is an order of magnitude more computationally efficient than the full-scale simulation.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gao, Kai; Chung, Eric T.; Gibson, Richard L.; Fu, Shubin; Efendiev, Yalchin
2015-06-05T23:59:59.000Z
The development of reliable methods for upscaling fine scale models of elastic media has long been an important topic for rock physics and applied seismology. Several effective medium theories have been developed to provide elastic parameters for materials such as finely layered media or randomly oriented or aligned fractures. In such cases, the analytic solutions for upscaled properties can be used for accurate prediction of wave propagation. However, such theories cannot be applied directly to homogenize elastic media with more complex, arbitrary spatial heterogeneity. We therefore propose a numerical homogenization algorithm based on multiscale finite element methods for simulating elasticmore »wave propagation in heterogeneous, anisotropic elastic media. Specifically, our method used multiscale basis functions obtained from a local linear elasticity problem with appropriately defined boundary conditions. Homogenized, effective medium parameters were then computed using these basis functions, and the approach applied a numerical discretization that is similar to the rotated staggered-grid finite difference scheme. Comparisons of the results from our method and from conventional, analytical approaches for finely layered media showed that the homogenization reliably estimated elastic parameters for this simple geometry. Additional tests examined anisotropic models with arbitrary spatial heterogeneity where the average size of the heterogeneities ranged from several centimeters to several meters, and the ratio between the dominant wavelength and the average size of the arbitrary heterogeneities ranged from 10 to 100. Comparisons to finite-difference simulations proved that the numerical homogenization was equally accurate for these complex cases.« less
Multi-scale problems, high performance computing and hybrid numerical methods
Paris-Sud XI, Université de
Multi-scale problems, high performance computing and hybrid numerical methods G. Balarac, G of High Performance Computing (HPC) is not anymore restricted to academia and scientific grand challenges
Multi-scale problems, high performance computing and hybrid numerical methods
Cottet, Georges-Henri
Multi-scale problems, high performance computing and hybrid numerical methods G. Balarac, G of High Performance Computing G. Balarac LEGI, CNRS and Universit´e de Grenoble, BP 53, 38041 Grenoble
Kim, G.; Pesaran, A.; Smith, K.; Graf, P.; Jun, M.; Yang, C.; Li, G.; Li, S.; Hochman, A.; Tselepidakis, D.; White, J.
2014-06-01T23:59:59.000Z
This presentation discusses the significant enhancement of computational efficiency in nonlinear multiscale battery model for computer aided engineering in current research at NREL.
Multi-Scale Multi-Dimensional Model for Better Cell Design and Management (Presentation)
Kim, G.-H.; Smith, K.
2008-09-01T23:59:59.000Z
Describes NREL's R&D to develop a multi-scale model to assist in designing better, more reliable lithium-ion battery cells for advanced vehicles.
Bauer, Georg; Gamnitzer, Peter [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany)] [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany); Gravemeier, Volker, E-mail: vgravem@lnm.mw.tum.de [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany) [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany); Emmy Noether Research Group “Computational Multiscale Methods for Turbulent Combustion”, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany); Wall, Wolfgang A. [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany)] [Institute for Computational Mechanics, Technische Universität München, Boltzmannstr. 15, 85747 Garching (Germany)
2013-10-15T23:59:59.000Z
Highlights: •We present a computational method for coupled multi-ion transport in turbulent flow. •The underlying formulation is a variational multiscale finite element method. •It is combined with the isogeometric concept for electrochemical systems. •Coupled multi-ion transport in fully turbulent Taylor–Couette flow is simulated. •This example is an important model problem for rotating cylinder electrodes. -- Abstract: Electrochemical processes, such as electroplating of large items in galvanic baths, are often coupled to turbulent flow. In this study, we propose an isogeometric residual-based variational multiscale finite element method for multi-ion transport in dilute electrolyte solutions under turbulent flow conditions. In other words, this means that the concepts of isogeometric discretization and variational multiscale methods are successfully combined for developing a method capable of simulating the challenging problem of coupled multi-ion transport in turbulent flow. We present a comprehensive three-dimensional computational method taking into account, among others, coupled convection–diffusion-migration equations subject to an electroneutrality constraint in combination with phenomenological electrode-kinetics modeling. The electrochemical subproblem is one-way coupled to turbulent incompressible flow via convection. Ionic mass transfer in turbulent Taylor–Couette flow is investigated, representing an important model problem for rotating-cylinder-electrode configurations. Multi-ion transport as considered here is an example for mass transport at high Schmidt number (Sc=1389). An isogeometric discretization is especially advantageous for the present problem, since (i) curved boundaries can be represented exactly, and (ii) it has been proven to provide very accurate solutions for flow quantities when being applied in combination with residual-based variational multiscale modeling. We demonstrate that the method is robust and provides results which are in good agreement with direct numerical simulation results as well as empirical mass-transfer correlations reported in literature.
Multiscale Modeling of Materials - Concepts and Illustration
Aditi Mallik; Keith Runge; James W. Dufty; Hai-Ping Cheng
2005-07-24T23:59:59.000Z
The approximate representation of a quantum solid as an equivalent composite semi-classical solid is considered for insulating materials. The composite is comprised of point ions moving on a potential energy surface. In the classical bulk domain this potential energy is represented by pair potentials constructed to give the same structure and elastic properties as the underlying quantum solid. In a small local quantum domain the potential is determined from a detailed quantum calculation of the electronic structure. The primary new ingredients are 1) a determination of the pair potential from quantum data for equilibrium and strained structures, 2) development of pseudo-atoms for a realistic treatment of charge densities where bonds have been broken to define the quantum domain, and 3) inclusion of polarization effects on the quantum domain due to its environment. This formal structure is illustrated in detail for an silica nanorod. For each configuration considered, the charge density of the entire solid is calculated quantum mechanically to provide the reference by which to judge the accuracy of the modeling.It is then shown that the quantum rod, the rod constructed from the classical pair potentials, and the composite classical/quantum rod all have the same equilibrium structure and response to elastic strain. The accuracy of the modeling is shown to apply for two quite different quantum chemical methods for the underlying quantum mechanics: transfer Hamiltonian and density functional methods.
Multiscale modeling for fluid transport in nanosystems.
Lee, Jonathan W.; Jones, Reese E.; Mandadapu, Kranthi Kiran; Templeton, Jeremy Alan; Zimmerman, Jonathan A.
2013-09-01T23:59:59.000Z
Atomistic-scale behavior drives performance in many micro- and nano-fluidic systems, such as mircrofludic mixers and electrical energy storage devices. Bringing this information into the traditionally continuum models used for engineering analysis has proved challenging. This work describes one such approach to address this issue by developing atomistic-to-continuum multi scale and multi physics methods to enable molecular dynamics (MD) representations of atoms to incorporated into continuum simulations. Coupling is achieved by imposing constraints based on fluxes of conserved quantities between the two regions described by one of these models. The impact of electric fields and surface charges are also critical, hence, methodologies to extend finite-element (FE) MD electric field solvers have been derived to account for these effects. Finally, the continuum description can have inconsistencies with the coarse-grained MD dynamics, so FE equations based on MD statistics were derived to facilitate the multi scale coupling. Examples are shown relevant to nanofluidic systems, such as pore flow, Couette flow, and electric double layer.
Multiscale geometric modeling of macromolecules I: Cartesian representation
Xia, Kelin [Department of Mathematics, Michigan State University, MI 48824 (United States)] [Department of Mathematics, Michigan State University, MI 48824 (United States); Feng, Xin [Department of Computer Science and Engineering, Michigan State University, MI 48824 (United States)] [Department of Computer Science and Engineering, Michigan State University, MI 48824 (United States); Chen, Zhan [Department of Mathematics, Michigan State University, MI 48824 (United States)] [Department of Mathematics, Michigan State University, MI 48824 (United States); Tong, Yiying [Department of Computer Science and Engineering, Michigan State University, MI 48824 (United States)] [Department of Computer Science and Engineering, Michigan State University, MI 48824 (United States); Wei, Guo-Wei, E-mail: wei@math.msu.edu [Department of Mathematics, Michigan State University, MI 48824 (United States) [Department of Mathematics, Michigan State University, MI 48824 (United States); Department of Biochemistry and Molecular Biology, Michigan State University, MI 48824 (United States)
2014-01-15T23:59:59.000Z
This paper focuses on the geometric modeling and computational algorithm development of biomolecular structures from two data sources: Protein Data Bank (PDB) and Electron Microscopy Data Bank (EMDB) in the Eulerian (or Cartesian) representation. Molecular surface (MS) contains non-smooth geometric singularities, such as cusps, tips and self-intersecting facets, which often lead to computational instabilities in molecular simulations, and violate the physical principle of surface free energy minimization. Variational multiscale surface definitions are proposed based on geometric flows and solvation analysis of biomolecular systems. Our approach leads to geometric and potential driven Laplace–Beltrami flows for biomolecular surface evolution and formation. The resulting surfaces are free of geometric singularities and minimize the total free energy of the biomolecular system. High order partial differential equation (PDE)-based nonlinear filters are employed for EMDB data processing. We show the efficacy of this approach in feature-preserving noise reduction. After the construction of protein multiresolution surfaces, we explore the analysis and characterization of surface morphology by using a variety of curvature definitions. Apart from the classical Gaussian curvature and mean curvature, maximum curvature, minimum curvature, shape index, and curvedness are also applied to macromolecular surface analysis for the first time. Our curvature analysis is uniquely coupled to the analysis of electrostatic surface potential, which is a by-product of our variational multiscale solvation models. As an expository investigation, we particularly emphasize the numerical algorithms and computational protocols for practical applications of the above multiscale geometric models. Such information may otherwise be scattered over the vast literature on this topic. Based on the curvature and electrostatic analysis from our multiresolution surfaces, we introduce a new concept, the polarized curvature, for the prediction of protein binding sites.
Multiscale/Multiphysics Modeling of Biomass Thermochemical Processes
Pannala, Sreekanth [ORNL; Simunovic, Srdjan [ORNL; Frantziskonis, G. [University of Arizona
2010-01-01T23:59:59.000Z
Computational problems in simulating biomass thermochemical processes involve coupling processes that span several orders of magnitude in space and time. Computational difficulties arise from the multitude of the problem governing equations, each typically applying over a narrow range of spatiotemporal scales, thus making it necessary to represent the processes as the result of the interaction of multiple physics modules, termed here as multiscale/multiphysics (MSMP) coupling. Predictive simulations for such processes require algorithms that can efficiently integrate the underlying MSMP methods across the scales in order to achieve prescribed accuracy and control the computational cost. In addition, MSMP algorithms must scale to one hundred thousand processors or more in order to effectively harness the new computational resources and accelerate the scientific advances. In this chapter, we discuss the state-of-the-art in modeling the macro-scale phenomena in a biomass pyrolysis reactor along with details of the shortcomings and prospects in improving predictability. We also introduce the various multiphysics modules needed to model thermochemical conversion at lower spatiotemporal scales. Furthermore, we illustrate the need for MSMP coupling for thermochemical processes in biomass and provide an overview of the wavelet-based coupling techniques we have developed recently. In particular, we provide details about the compound wavelet matrix (CWM) and the dynamic CWM (dCWM) methods and show they are highly efficient in transferring information among multiphysics models across multiple temporal and spatial scales. The algorithmic gain is in addition to the parallel spatial scalability from traditional domain decomposition methods. The CWM algorithms are serial in time and limited by the smallest-system time-scales. In order to relax this algorithmic constraint, we have recently coupled time parallel (TP) algorithms to CWM, thus yielding a novel approach termed tpCWM. We present preliminary results from the tpCWM technique, indicating that we can accelerate time-to-solution by 2 to 3-orders of magnitude even on 20-processors and this can potentially constitute a new paradigm for MSMP simulations. If such improvements in simulation capability can be generalized, the tpCWM approach can lead the way to predictive simulations of biomass thermochemical processes.
Multiscale Design of Advanced Materials based on Hybrid Ab Initio and Quasicontinuum Methods
Luskin, Mitchell [University of Minnesota
2014-03-12T23:59:59.000Z
This project united researchers from mathematics, chemistry, computer science, and engineering for the development of new multiscale methods for the design of materials. Our approach was highly interdisciplinary, but it had two unifying themes: first, we utilized modern mathematical ideas about change-of-scale and state-of-the-art numerical analysis to develop computational methods and codes to solve real multiscale problems of DOE interest; and, second, we took very seriously the need for quantum mechanics-based atomistic forces, and based our methods on fast solvers of chemically accurate methods.
A computational strategy for multiscale systems with applications to Lorenz 96 model
Van Den Eijnden, Eric
A computational strategy for multiscale systems with applications to Lorenz 96 model Ibrahim 2004 Available online Abstract Numerical schemes for systems with multiple spatio-temporal scales are investigated. The multiscale schemes use asymptotic results for this type of systems which guarantee
Multiscale multiphysics and multidomain models—Flexibility and rigidity
Xia, Kelin [Department of Mathematics, Michigan State University, East Lansing, Michigan 48824 (United States)] [Department of Mathematics, Michigan State University, East Lansing, Michigan 48824 (United States); Opron, Kristopher [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824 (United States)] [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824 (United States); Wei, Guo-Wei, E-mail: wei@math.msu.edu [Department of Mathematics, Michigan State University, East Lansing, Michigan 48824 (United States) [Department of Mathematics, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States)
2013-11-21T23:59:59.000Z
The emerging complexity of large macromolecules has led to challenges in their full scale theoretical description and computer simulation. Multiscale multiphysics and multidomain models have been introduced to reduce the number of degrees of freedom while maintaining modeling accuracy and achieving computational efficiency. A total energy functional is constructed to put energies for polar and nonpolar solvation, chemical potential, fluid flow, molecular mechanics, and elastic dynamics on an equal footing. The variational principle is utilized to derive coupled governing equations for the above mentioned multiphysical descriptions. Among these governing equations is the Poisson-Boltzmann equation which describes continuum electrostatics with atomic charges. The present work introduces the theory of continuum elasticity with atomic rigidity (CEWAR). The essence of CEWAR is to formulate the shear modulus as a continuous function of atomic rigidity. As a result, the dynamics complexity of a macromolecular system is separated from its static complexity so that the more time-consuming dynamics is handled with continuum elasticity theory, while the less time-consuming static analysis is pursued with atomic approaches. We propose a simple method, flexibility-rigidity index (FRI), to analyze macromolecular flexibility and rigidity in atomic detail. The construction of FRI relies on the fundamental assumption that protein functions, such as flexibility, rigidity, and energy, are entirely determined by the structure of the protein and its environment, although the structure is in turn determined by all the interactions. As such, the FRI measures the topological connectivity of protein atoms or residues and characterizes the geometric compactness of the protein structure. As a consequence, the FRI does not resort to the interaction Hamiltonian and bypasses matrix diagonalization, which underpins most other flexibility analysis methods. FRI's computational complexity is of O(N{sup 2}) at most, where N is the number of atoms or residues, in contrast to O(N{sup 3}) for Hamiltonian based methods. We demonstrate that the proposed FRI gives rise to accurate prediction of protein B-Factor for a set of 263 proteins. We show that a parameter free FRI is able to achieve about 95% accuracy of the parameter optimized FRI. An interpolation algorithm is developed to construct continuous atomic flexibility functions for visualization and use with CEWAR.
A Mathematical Analysis of Atomistic-to-Continuum (AtC) Multiscale Coupling Methods
Gunzburger, Max
2013-11-13T23:59:59.000Z
We have worked on several projects aimed at improving the efficiency and understanding of multiscale methods, especially those applicable to problems involving atomistic-to-continuum coupling. Activities include blending methods for AtC coupling and efficient quasi-continuum methods for problems with long-range interactions.
A computational method to extract macroscopic variables and their dynamics in multiscale systems
Gary Froyland; Georg A. Gottwald; Andy Hammerlindl
2014-09-29T23:59:59.000Z
This paper introduces coordinate-independent methods for analysing multiscale dynamical systems using numerical techniques based on the transfer operator and its adjoint. In particular, we present a method for testing whether an arbitrary dynamical system exhibits multiscale behaviour and for estimating the time-scale separation. For systems with such behaviour, we establish techniques for analysing the fast dynamics in isolation, extracting slow variables for the system, and accurately simulating these slow variables at a large time step. We illustrate our method with numerical examples and show how the reduced slow dynamics faithfully represents statistical features of the full dynamics which are not coordinate dependent.
Multiscale approach for modeling hot mix asphalt
Dessouky, Samer Hassan
2005-08-29T23:59:59.000Z
presents the development of elastic and visco-plastic models that account for important aspects of the microstructure distribution in modeling the macroscopic behavior of HMA. In the first part of this study, an approach is developed to introduce a length...
Multiscale modeling of clay-water systems
Ebrahimi, Davoud
2014-01-01T23:59:59.000Z
The engineering properties of soils are highly affected by clay content and clay-water interactions. However, existing macro-scale continuum models have no length scale to describe the evolution of the clay microstructure ...
Application of multiscale water and energy balance models on a tallgrass prairie
Famiglietti, J. S; Wood, E. F
1994-01-01T23:59:59.000Z
models of water and energy balance, Ph.D. dissertation,variable water and energy balance processes, Water Resour.OF MULTISCALE WATER AND ENERGY BALANCE MODELS sented at the
A Multiscale Model for Coupled Heat Conduction and Deformations of Viscoelastic Composites
Khan, Kamran Ahmed
2012-07-16T23:59:59.000Z
This study introduces a multiscale model for analyzing nonlinear thermo-viscoelastic responses of particulate composites. A simplified micromechanical model consisting of four sub-cells, i.e., one particle and three matrix sub-cells is formulated...
Accelerating Particle Filter using Randomized Multiscale and Fast Multipole Type Methods
Averbuch, Amir
1 Accelerating Particle Filter using Randomized Multiscale and Fast Multipole Type Methods Gil that accelerates the computation of particle filters. Unlike the conventional way, which calculates weights over Shabat, Yaniv Shmueli, Amit Bermanis and Amir Averbuch Abstract--Particle filter is a powerful method
Integrated Multiscale Modeling of Molecular Computing Devices
Weinan E
2012-03-29T23:59:59.000Z
The main bottleneck in modeling transport in molecular devices is to develop the correct formulation of the problem and efficient algorithms for analyzing the electronic structure and dynamics using, for example, the time-dependent density functional theory. We have divided this task into several steps. The first step is to developing the right mathematical formulation and numerical algorithms for analyzing the electronic structure using density functional theory. The second step is to study time-dependent density functional theory, particularly the far-field boundary conditions. The third step is to study electronic transport in molecular devices. We are now at the end of the first step. Under DOE support, we have made subtantial progress in developing linear scaling and sub-linear scaling algorithms for electronic structure analysis. Although there has been a huge amount of effort in the past on developing linear scaling algorithms, most of the algorithms developed suffer from the lack of robustness and controllable accuracy. We have made the following progress: (1) We have analyzed thoroughly the localization properties of the wave-functions. We have developed a clear understanding of the physical as well as mathematical origin of the decay properties. One important conclusion is that even for metals, one can choose wavefunctions that decay faster than any algebraic power. (2) We have developed algorithms that make use of these localization properties. Our algorithms are based on non-orthogonal formulations of the density functional theory. Our key contribution is to add a localization step into the algorithm. The addition of this localization step makes the algorithm quite robust and much more accurate. Moreover, we can control the accuracy of these algorithms by changing the numerical parameters. (3) We have considerably improved the Fermi operator expansion (FOE) approach. Through pole expansion, we have developed the optimal scaling FOE algorithm.
Multiscale modeling of oscillations and spiral waves in Dictyostelium populations
Javad Noorbakhsh; David Schwab; Allyson Sgro; Thomas Gregor; Pankaj Mehta
2014-09-12T23:59:59.000Z
Unicellular organisms exhibit elaborate collective behaviors in response to environmental cues. These behaviors are controlled by complex biochemical networks within individual cells and coordinated through cell-to-cell communication. Describing these behaviors requires new mathematical models that can bridge scales -- from biochemical networks within individual cells to spatially structured cellular populations. Here, we present a family of multiscale models for the emergence of spiral waves in the social amoeba Dictyostelium discoideum. Our models exploit new experimental advances that allow for the direct measurement and manipulation of the small signaling molecule cAMP used by Dictyostelium cells to coordinate behavior in cellular populations. Inspired by recent experiments, we model the Dictyostelium signaling network as an excitable system coupled to various pre-processing modules. We use this family of models to study spatially unstructured populations by constructing phase diagrams that relate the properties of population-level oscillations to parameters in the underlying biochemical network. We then extend our models to include spatial structure and show how they naturally give rise to spiral waves. Our models exhibit a wide range of novel phenomena including a density dependent frequency change, bistability, and dynamic death due to slow cAMP dynamics. Our modeling approach provides a powerful tool for bridging scales in modeling of Dictyostelium populations.
Multi-Scale Coupling in Ocean and Climate Modeling
Zhengyu Liu, Leslie Smith
2009-08-14T23:59:59.000Z
We have made significant progress on several projects aimed at understanding multi-scale dynamics in geophysical flows. Large-scale flows in the atmosphere and ocean are influenced by stable density stratification and rotation. The presence of stratification and rotation has important consequences through (i) the conservation of potential vorticity q = {omega} {center_dot} {del} {rho}, where {omega} is the total vorticity and {rho} is the density, and (ii) the existence of waves that affect the redistribution of energy from a given disturbance to the flow. Our research is centered on quantifying the effects of potential vorticity conservation and of wave interactions for the coupling of disparate time and space scales in the oceans and the atmosphere. Ultimately we expect the work to help improve predictive capabilities of atmosphere, ocean and climate modelers. The main findings of our research projects are described.
Cummings, P. T.
2010-02-08T23:59:59.000Z
This document reports the outcomes of the Computational Nanoscience Project, "Integrated Multiscale Modeling of Molecular Computing Devices". It includes a list of participants and publications arising from the research supported.
Analysis of the ventilation systems in the Dartford tunnels using a multiscale modelling approach
Colella, Francesco; Rein, Guillermo; Carvel, Ricky O; Reszka, Pedro; Torero, Jose L
2010-01-01T23:59:59.000Z
The capabilities of the ventilation systems in the two road tunnels at Dartford (London, UK) are analysed using a multi-scale modelling approach. Both tunnels have complex semi-transverse ventilation systems with jet fans to control longitudinal...
The bootstrap multiscale analysis for the multi-particle Anderson model
Abel Klein; Son T. Nguyen
2012-12-22T23:59:59.000Z
We extend the bootstrap multi-scale analysis developed by Germinet and Klein to the multi-particle Anderson model, obtaining Anderson localization, dynamical localization, and decay of eigenfunction correlations.
Paris-Sud XI, Université de
Analysis of the finite element heterogeneous multiscale method for nonlinear elliptic homogenization problems. Assyr Abdulle and Gilles Vilmart September 28, 2012 Abstract An analysis of the finite finite elements. Op- timal a-priori error estimates are obtained for the H1 and L2 norms, error bounds
A multiscale mathematical model of cancer, and its use in analyzing irradiation therapies
Benjamin Ribba; Thierry Colin; Santiago Schnell
2006-06-24T23:59:59.000Z
Background: Radiotherapy outcomes are usually predicted using the Linear Quadratic model. However, this model does not integrate complex features of tumor growth, in particular cell cycle regulation. Methods: In this paper, we propose a multiscale model of cancer growth based on the genetic and molecular features of the evolution of colorectal cancer. The model includes key genes, cellular kinetics, tissue dynamics, macroscopic tumor evolution and radiosensitivity dependence on the cell cycle phase. We investigate the role of gene-dependent cell cycle regulation in the response of tumors to therapeutic irradiation protocols. Results: Simulation results emphasize the importance of tumor tissue features and the need to consider regulating factors such as hypoxia, as well as tumor geometry and tissue dynamics, in predicting and improving radiotherapeutic efficacy. Conclusion: This model provides insight into the coupling of complex biological processes, which leads to a better understanding of oncogenesis. This will hopefully lead to improved irradiation therapy.
A Multiscale Dynamo Model Driven by Quasi-geostrophic Convection
Calkins, Michael A; Tobias, Steven M; Aurnou, Jonathan M
2015-01-01T23:59:59.000Z
A convection-driven multiscale dynamo model is developed for the plane layer geometry in the limit of low Rossby number. The small-scale fluctuating dynamics are described by a magnetically-modified quasi-geostrophic equation set, and the large-scale mean dynamics are governed by a diagnostic thermal wind balance. The model utilizes three timescales that respectively characterize the convective timescale, the large-scale magnetic diffusion timescale, and the large-scale thermal diffusion timescale. Distinct equations are derived for the cases of order one and low magnetic Prandtl number. It is shown that the low magnetic Prandtl number model is characterized by a magnetic to kinetic energy ratio that is asymptotically large, with ohmic dissipation dominating viscous dissipation on the large-scales. For the order one magnetic Prandtl number model the magnetic and kinetic energies are equipartitioned and both ohmic and viscous dissipation are weak on the large-scales; large-scale ohmic dissipation occurs in thi...
Components for Atomistic-to-Continuum Multiscale Modeling of Flow in Micro- and Nanofluidic Systems
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Adalsteinsson, Helgi; Debusschere, Bert J.; Long, Kevin R.; Najm, Habib N.
2008-01-01T23:59:59.000Z
Micro- and nanofluidics pose a series of significant challenges for science-based modeling. Key among those are the wide separation of length- and timescales between interface phenomena and bulk flow and the spatially heterogeneous solution properties near solid-liquid interfaces. It is not uncommon for characteristic scales in these systems to span nine orders of magnitude from the atomic motions in particle dynamics up to evolution of mass transport at the macroscale level, making explicit particle models intractable for all but the simplest systems. Recently, atomistic-to-continuum (A2C) multiscale simulations have gained a lot of interest as an approach to rigorously handle particle-levelmore »dynamics while also tracking evolution of large-scale macroscale behavior. While these methods are clearly not applicable to all classes of simulations, they are finding traction in systems in which tight-binding, and physically important, dynamics at system interfaces have complex effects on the slower-evolving large-scale evolution of the surrounding medium. These conditions allow decomposition of the simulation into discrete domains, either spatially or temporally. In this paper, we describe how features of domain decomposed simulation systems can be harnessed to yield flexible and efficient software for multiscale simulations of electric field-driven micro- and nanofluidics.« less
Common themes, methods, and applications in multiscale science
Baker, G.A. Jr.
1997-10-01T23:59:59.000Z
In 1993, under the leadership of Richard Slansky, the T-Division Director, an initiative was started to facilitate cross communications and interactions between a large number of different workers who were, from their own perspectives and with regard to their own challenges, in fact working on very difficult problems which involved multiple size and time scales. The realization of this common element had the potential for valuable mutual interaction. His initiative led initially to a competency development initiative and subsequently to a broadening recognition of the importance of multiscale science and a broadening application of it to problems and concerns inherent in significant fields of endeavor at the Los Alamos National Laboratory. One of the aspects of this effort was a series of meetings which emphasizes cross communication between the workers. It was realized early on that this cross communication would be fare more effective, considering the difficult technical nature and that the range of the material was well outside the area of specialization of individual members of the group, if notes were taken, written up, and disseminated. This report represents the collection of these notes.
Bayesian data assimilation for stochastic multiscale models of transport in porous media.
Marzouk, Youssef M. (Massachusetts Institute of Technology, Cambridge, MA); van Bloemen Waanders, Bart Gustaaf (Sandia National Laboratories, Albuquerque NM); Parno, Matthew (Massachusetts Institute of Technology, Cambridge, MA); Ray, Jaideep; Lefantzi, Sophia; Salazar, Luke (Sandia National Laboratories, Albuquerque NM); McKenna, Sean Andrew (Sandia National Laboratories, Albuquerque NM); Klise, Katherine A. (Sandia National Laboratories, Albuquerque NM)
2011-10-01T23:59:59.000Z
We investigate Bayesian techniques that can be used to reconstruct field variables from partial observations. In particular, we target fields that exhibit spatial structures with a large spectrum of lengthscales. Contemporary methods typically describe the field on a grid and estimate structures which can be resolved by it. In contrast, we address the reconstruction of grid-resolved structures as well as estimation of statistical summaries of subgrid structures, which are smaller than the grid resolution. We perform this in two different ways (a) via a physical (phenomenological), parameterized subgrid model that summarizes the impact of the unresolved scales at the coarse level and (b) via multiscale finite elements, where specially designed prolongation and restriction operators establish the interscale link between the same problem defined on a coarse and fine mesh. The estimation problem is posed as a Bayesian inverse problem. Dimensionality reduction is performed by projecting the field to be inferred on a suitable orthogonal basis set, viz. the Karhunen-Loeve expansion of a multiGaussian. We first demonstrate our techniques on the reconstruction of a binary medium consisting of a matrix with embedded inclusions, which are too small to be grid-resolved. The reconstruction is performed using an adaptive Markov chain Monte Carlo method. We find that the posterior distributions of the inferred parameters are approximately Gaussian. We exploit this finding to reconstruct a permeability field with long, but narrow embedded fractures (which are too fine to be grid-resolved) using scalable ensemble Kalman filters; this also allows us to address larger grids. Ensemble Kalman filtering is then used to estimate the values of hydraulic conductivity and specific yield in a model of the High Plains Aquifer in Kansas. Strong conditioning of the spatial structure of the parameters and the non-linear aspects of the water table aquifer create difficulty for the ensemble Kalman filter. We conclude with a demonstration of the use of multiscale stochastic finite elements to reconstruct permeability fields. This method, though computationally intensive, is general and can be used for multiscale inference in cases where a subgrid model cannot be constructed.
Luscher, Darby J.
2010-04-01T23:59:59.000Z
All materials are heterogeneous at various scales of observation. The influence of material heterogeneity on nonuniform response and microstructure evolution can have profound impact on continuum thermomechanical response at macroscopic “engineering” scales. In many cases, it is necessary to treat this behavior as a multiscale process thus integrating the physical understanding of material behavior at various physical (length and time) scales in order to more accurately predict the thermomechanical response of materials as their microstructure evolves. The intent of the dissertation is to provide a formal framework for multiscale hierarchical homogenization to be used in developing constitutive models.
Multi-Scale Multi-physics Methods Development for the Calculation of Hot-Spots in the NGNP
Downar, Thomas; Seker, Volkan
2013-04-30T23:59:59.000Z
Radioactive gaseous fission products are released out of the fuel element at a significantly higher rate when the fuel temperature exceeds 1600°C in high-temperature gas-cooled reactors (HTGRs). Therefore, it is of paramount importance to accurately predict the peak fuel temperature during all operational and design-basis accident conditions. The current methods used to predict the peak fuel temperature in HTGRs, such as the Next-Generation Nuclear Plant (NGNP), estimate the average fuel temperature in a computational mesh modeling hundreds of fuel pebbles or a fuel assembly in a pebble-bed reactor (PBR) or prismatic block type reactor (PMR), respectively. Experiments conducted in operating HTGRs indicate considerable uncertainty in the current methods and correlations used to predict actual temperatures. The objective of this project is to improve the accuracy in the prediction of local "hot" spots by developing multi-scale, multi- physics methods and implementing them within the framework of established codes used for NGNP analysis. The multi-scale approach which this project will implement begins with defining suitable scales for a physical and mathematical model and then deriving and applying the appropriate boundary conditions between scales. The macro scale is the greatest length that describes the entire reactor, whereas the meso scale models only a fuel block in a prismatic reactor and ten to hundreds of pebbles in a pebble bed reactor. The smallest scale is the micro scale--the level of a fuel kernel of the pebble in a PBR and fuel compact in a PMR--which needs to be resolved in order to calculate the peak temperature in a fuel kernel.
Multiscale Modeling and Solution Multiplicity in Catalytic Pellet Reactors Kedar Kulkarni,
Linninger, Andreas A.
Multiscale Modeling and Solution Multiplicity in Catalytic Pellet Reactors Kedar Kulkarni, Jeonghwa phenomena in catalytic pellet reactors are often difficult to analyze because of coupling between heat at the macroscopic level as well as the catalyst pellets at the microscopic level. The resulting approach yields
Modeling of the multiscale dispersion of nanoparticles in a hematite coating , F. Willot1
Boyer, Edmond
Modeling of the multiscale dispersion of nanoparticles in a hematite coating E. Couka1 , F. Willot1 conclude in Sec. (6). 2. Hematite nanocubes coating 2.1. Dispersion of nanoparticles In this work, we-Auguste Desbručres, 91003 Evry, France. Images of a hematite-based epoxy coating are obtained by scanning electron
Noise clinic: some good and bad patients Multiscale signal-dependent noise model
Mayberry, Marty
Noise clinic: some good and bad patients Multiscale signal-dependent noise model Noise estimation recipes illustrated by DCT References The noise clinic Miguel Colom, Marc Lebrun, Jean-Michel Morel CMLA, ENS Cachan Saarbr¨ucken, September 2013 Miguel Colom, Marc Lebrun, Jean-Michel Morel The noise clinic
Uncertainty quantification using multiscale methods for porous media flows
Dostert, Paul Francis
2009-05-15T23:59:59.000Z
known formulations of the constitutive relations: Haverkamp model [25] : ?(u) = ?(?s ??r)?+|u|? +?r, k(x,u) = Ks(x) AA+|u|?. van Genuchten model [43] : ?(u) = ?(?s ??r)[1+(?|u|)n]m +?r, k(x,u) = Ks(x) braceleftbig1?(?|u|)n?1 [1+(?|u|)n]?mbracerightbig2... [1+(?|u|)n]m/2 . Exponential model [44] : ?(u) = ?se?u, (2.10) k(x,u) = Ks(x)e?u. Irmay model [28] : ?(u) = ?r +(?s ??r)e?u, (2.11) k(x,u) = Ks(x) parenleftbigg??? r ?s ??r parenrightbiggm . In each of the above constitutive relations...
MULTISCALE ITERATIVE METHODS, COARSE LEVEL OPERATOR CONSTRUCTION AND DISCRETE HOMOGENIZATION
locally strong varying phenomena on a microscale level, the grid for numerical simulation can not be chosen sufficiently fine enough due to reasons of storage requirements and numerical complexity. We apply the Galerkin approximation, used in multi grid methods for determining coarse grid equations
A Multiscale Modeling Approach to Analyze Filament-Wound Composite Pressure Vessels
Nguyen, Ba Nghiep; Simmons, Kevin L.
2013-07-22T23:59:59.000Z
A multiscale modeling approach to analyze filament-wound composite pressure vessels is developed in this article. The approach, which extends the Nguyen et al. model [J. Comp. Mater. 43 (2009) 217] developed for discontinuous fiber composites to continuous fiber ones, spans three modeling scales. The microscale considers the unidirectional elastic fibers embedded in an elastic-plastic matrix obeying the Ramberg-Osgood relation and J2 deformation theory of plasticity. The mesoscale behavior representing the composite lamina is obtained through an incremental Mori-Tanaka type model and the Eshelby equivalent inclusion method [Proc. Roy. Soc. Lond. A241 (1957) 376]. The implementation of the micro-meso constitutive relations in the ABAQUS® finite element package (via user subroutines) allows the analysis of a filament-wound composite pressure vessel (macroscale) to be performed. Failure of the composite lamina is predicted by a criterion that accounts for the strengths of the fibers and of the matrix as well as of their interface. The developed approach is demonstrated in the analysis of a filament-wound pressure vessel to study the effect of the lamina thickness on the burst pressure. The predictions are favorably compared to the numerical and experimental results by Lifshitz and Dayan [Comp. Struct. 32 (1995) 313].
Hierarchical Multiscale Modeling of Macromolecules and their Assemblies
Peter Ortoleva; Abhishek Singharoy; Stephen Pankavich
2013-01-24T23:59:59.000Z
Soft materials (e.g., enveloped viruses, liposomes, membranes and supercooled liquids) simultaneously deform or display collective behaviors, while undergoing atomic scale vibrations and collisions. While the multiple space-time character of such systems often makes traditional molecular dynamics simulation impractical, a multiscale approach has been presented that allows for long-time simulation with atomic detail based on the co-evolution of slowly-varying order parameters (OPs) with the quasi-equilibrium probability density of atomic configurations. However, this approach breaks down when the structural change is extreme, or when nearest-neighbor connectivity of atoms is not maintained. In the current study, a self-consistent approach is presented wherein OPs and a reference structure co-evolve slowly to yield long-time simulation for dynamical soft-matter phenomena such as structural transitions and self assembly. The development begins with the Liouville equation for N classical atoms and an ansatz on the form of the associated N-atom probability density. Multiscale techniques are used to derive Langevin equations for the coupled OP configurational dynamics. The net result is a set of equations for the coupled stochastic dynamics of the OPs and centers of mass of the subsystems that constitute a soft material body. The theory is based on an all-atom methodology and an interatomic force field, and therefore enables calibration-free simulations of soft matter, such as macromolecular assemblies.
Wang Fei; Zhao Xuezeng [School of Mechanical and Electronic Engineering, Harbin Institute of Technology, Harbin 150001 (China); Li Ning [Shanghai Second Polytechnic University, Shanghai 201209 (China)
2010-10-15T23:59:59.000Z
We introduce a multiscale characterization method for line edge roughness (LER) based on redundant second generation wavelet transform. This method involves decomposing LER characteristics into independent bands with different spatial frequency components at different scales, and analyzing the reconstructed signals to work out the roughness exponent, the spatial frequency distribution characteristics, as well as the rms value. The effect of noise can be predicted using detailed signals in the minimum space of scale. This method was applied to numerical profiles for validation. Results show that according to the line edge profiles with similar amplitudes, the roughness exponent R can effectively reflect the degree of irregularity of LER and intuitively provide information on LER spatial frequency distribution.
Multiscale modeling of solar cells with interface phenomena
Foster, David H; Peszynska, Malgorzata; Schneider, Guenter
2013-01-01T23:59:59.000Z
We describe a mathematical model for heterojunctions in semiconductors which can be used, e.g., for modeling higher efficiency solar cells. The continuum model involves well-known drift-diffusion equations posed away from the interface. These are coupled with interface conditions with a nonhomogeneous jump for the potential, and Robin-like interface conditions for carrier transport. The interface conditions arise from approximating the interface region by a lower-dimensional manifold. The data for the interface conditions are calculated by a Density Functional Theory (DFT) model over a few atomic layers comprising the interface region. We propose a domain decomposition method (DDM) approach to decouple the continuum model on subdomains which is implemented in every step of the Gummel iteration. We show results for CIGS/CdS, Si/ZnS, and Si/GaAs heterojunctions.
FULL CRITICAL REVIEW Novel approaches to multiscale modelling in
Elliott, James
of nanocrystalline metals and alloys, crack propagation in brittle solids, polymer chain relaxation in nanocomposites, Materials modelling, Molecular dynamics, Monte Carlo, Finite element analysis, Hierarchical/hybrid models and mechanical properties, although some discussion of electrical percolation in polymer nanocomposites
Continuum-based Multiscale Computational Damage Modeling of Cementitous Composites
Kim, Sun-Myung
2011-08-08T23:59:59.000Z
of Advisory Committee: Dr. Rashid K. Abu Al-Rub Based on continuum damage mechanics (CDM), an isotropic and anisotropic damage model coupled with a novel plasticity model for plain concrete is proposed in this research. Two different damage evolution laws... in the commercial finite element analysis program Abaqus, and the overall performance of the proposed model is verified by comparing the model predictions to various experimental data on macroscopic level. Using the proposed coupled plasticity...
Journal of Multiscale Modelling Vol. 1, No. 1 (2009) 2155
Ghosh, Somnath
2009-01-01T23:59:59.000Z
capability of failure properties, such as strain to fail- ure, ductility and fracture toughness FRAMEWORK FOR CHARACTERIZATION AND MODELING DUCTILE FRACTURE IN HETEROGENEOUS ALUMINUM ALLOYS SOMNATH GHOSH components contributing to the overall framework of multi- scale modeling of ductile fracture in aluminum
Novel approaches to multiscale modelling in materials science
Elliott, James
of nanocrystalline metals and alloys, crack propagation in brittle solids, polymer chain relaxation in nanocomposites, Materials modelling, Molecular dynamics, Monte Carlo, Finite element analysis, Hierarchical/hybrid models in polymer nanocomposites and the control of nucleation in biomimetic materials is also given. Many
A stochastic multiscale model for electricity generation capacity ...
2011-04-21T23:59:59.000Z
efficient method for coupling multiple temporal scales using the framework of singular perturbation ..... used to capture this specific structure in energy data. ...... Data. Center, http://www.ncdc.noaa.gov/oa/ncdc.html. [Řksendal and Sulem, 2007] ...
Airflow in a Multiscale Subject-Specific Breathing Human Lung Model
Choi, Jiwoong; Hoffman, Eric A; Tawhai, Merryn H; Lin, Ching-Long
2013-01-01T23:59:59.000Z
The airflow in a subject-specific breathing human lung is simulated with a multiscale computational fluid dynamics (CFD) lung model. The three-dimensional (3D) airway geometry beginning from the mouth to about 7 generations of airways is reconstructed from the multi-detector row computed tomography (MDCT) image at the total lung capacity (TLC). Along with the segmented lobe surfaces, we can build an anatomically-consistent one-dimensional (1D) airway tree spanning over more than 20 generations down to the terminal bronchioles, which is specific to the CT resolved airways and lobes (J Biomech 43(11): 2159-2163, 2010). We then register two lung images at TLC and the functional residual capacity (FRC) to specify subject-specific CFD flow boundary conditions and deform the airway surface mesh for a breathing lung simulation (J Comput Phys 244:168-192, 2013). The 1D airway tree bridges the 3D CT-resolved airways and the registration-derived regional ventilation in the lung parenchyma, thus a multiscale model. Larg...
Wang, Yuan; Wang, Minghuai; Zhang, Renyi; Ghan, Steven J.; Lin, Yun; Hu, Jiaxi; Pan, Bowen; Levy, Misti; Jiang, Jonathan; Molina, Mario J.
2014-05-13T23:59:59.000Z
Atmospheric aerosols impact weather and global general circulation by modifying cloud and precipitation processes, but the magnitude of cloud adjustment by aerosols remains poorly quantified and represents the largest uncertainty in estimated forcing of climate change. Here we assess the impacts of anthropogenic aerosols on the Pacific storm track using a multi-scale global aerosol-climate model (GCM). Simulations of two aerosol scenarios corresponding to the present day and pre-industrial conditions reveal long-range transport of anthropogenic aerosols across the north Pacific and large resulting changes in the aerosol optical depth, cloud droplet number concentration, and cloud and ice water paths. Shortwave and longwave cloud radiative forcing at the top of atmosphere are changed by - 2.5 and + 1.3 W m-2, respectively, by emission changes from pre-industrial to present day, and an increased cloud-top height indicates invigorated mid-latitude cyclones. The overall increased precipitation and poleward heat transport reflect intensification of the Pacific storm track by anthropogenic aerosols. Hence, this work provides for the first time a global perspective of the impacts of Asian pollution outflows from GCMs. Furthermore, our results suggest that the multi-scale modeling framework is essential in producing the aerosol invigoration effect of deep convective clouds on the global scale.
Multi-Scale Indentation Hardness Testing; A Correlation and Model
Bennett, Damon W.
2010-01-20T23:59:59.000Z
This thesis presents the research results of a correlation and model based on nano and macroindentation hardness measurements. The materials used to develop and test the correlation include bulk tantalum and O1 tool steel. ...
Multiscale Modeling and Simulation of Organic Solar Cells
de Falco, Carlo; Sacco, Riccardo; Verri, Maurizio
2012-01-01T23:59:59.000Z
In this article, we continue our mathematical study of organic solar cells (OSCs) and propose a two-scale (micro- and macro-scale) model of heterojunction OSCs with interface geometries characterized by an arbitrarily complex morphology. The microscale model consists of a system of partial and ordinary differential equations in an heterogeneous domain, that provides a full description of excitation/transport phenomena occurring in the bulk regions and dissociation/recombination processes occurring in a thin material slab across the interface. The macroscale model is obtained by a micro-to-macro scale transition that consists of averaging the mass balance equations in the normal direction across the interface thickness, giving rise to nonlinear transmission conditions that are parametrized by the interfacial width. These conditions account in a lumped manner for the volumetric dissociation/recombination phenomena occurring in the thin slab and depend locally on the electric field magnitude and orientation. Usi...
Pesaran, A.; Kim, G. H.; Smith, K.; Santhanagopalan, S.; Lee, K. J.
2012-05-01T23:59:59.000Z
This 2012 Annual Merit Review presentation gives an overview of the Computer-Aided Engineering of Batteries (CAEBAT) project and introduces the Multi-Scale, Multi-Dimensional model for modeling lithium-ion batteries for electric vehicles.
Concurrent multiscale computational modeling for dense dry granular materials interfacing
Regueiro, Richard A.
of interfacial mechanics between granular soil and tire, tool, or penetrometer, while properly representing far computational modeling of interfacial mechanics between granular materials and deformable solid bodies, agricultural grains (in silo flows), dry soils (sand, silt, gravel), and lunar and martian regolith (soil found
Majda, Andrew J.
Multiscale models for synoptic-mesoscale interactions in the ocean1 Ian Grooms , K. Shafer Smith of the midlatitude oceanic synoptic scale -- where coherent features such as jets and rings form -- and the mesoscale, defined by the internal deformation scale. The synoptic scale and mesoscale overlap at low and mid
T.A> Buscheck; Y. Sun; Y. Hao
2006-03-28T23:59:59.000Z
The MultiScale ThermoHydrologic Model (MSTHM) predicts thermal-hydrologic (TH) conditions within emplacement tunnels (drifts) and in the adjoining host rock at Yucca Mountain, Nevada, which is the proposed site for a radioactive waste repository in the US. Because these predictions are used in the performance assessment of the Yucca Mountain repository, they must address the influence of variability and uncertainty of the engineered- and natural-system parameters that significantly influence those predictions. Parameter-sensitivity studies show that the MSTHM predictions adequately propagate the influence of parametric variability and uncertainty. Model-validation studies show that the influence of conceptual-model uncertainty on the MSTHM predictions is insignificant compared to that of parametric uncertainty, which is propagated through the MSTHM.
Anh Bui; Nam Dinh; Brian Williams
2013-09-01T23:59:59.000Z
In addition to validation data plan, development of advanced techniques for calibration and validation of complex multiscale, multiphysics nuclear reactor simulation codes are a main objective of the CASL VUQ plan. Advanced modeling of LWR systems normally involves a range of physico-chemical models describing multiple interacting phenomena, such as thermal hydraulics, reactor physics, coolant chemistry, etc., which occur over a wide range of spatial and temporal scales. To a large extent, the accuracy of (and uncertainty in) overall model predictions is determined by the correctness of various sub-models, which are not conservation-laws based, but empirically derived from measurement data. Such sub-models normally require extensive calibration before the models can be applied to analysis of real reactor problems. This work demonstrates a case study of calibration of a common model of subcooled flow boiling, which is an important multiscale, multiphysics phenomenon in LWR thermal hydraulics. The calibration process is based on a new strategy of model-data integration, in which, all sub-models are simultaneously analyzed and calibrated using multiple sets of data of different types. Specifically, both data on large-scale distributions of void fraction and fluid temperature and data on small-scale physics of wall evaporation were simultaneously used in this work’s calibration. In a departure from traditional (or common-sense) practice of tuning/calibrating complex models, a modern calibration technique based on statistical modeling and Bayesian inference was employed, which allowed simultaneous calibration of multiple sub-models (and related parameters) using different datasets. Quality of data (relevancy, scalability, and uncertainty) could be taken into consideration in the calibration process. This work presents a step forward in the development and realization of the “CIPS Validation Data Plan” at the Consortium for Advanced Simulation of LWRs to enable quantitative assessment of the CASL modeling of Crud-Induced Power Shift (CIPS) phenomenon, in particular, and the CASL advanced predictive capabilities, in general. This report is prepared for the Department of Energy’s Consortium for Advanced Simulation of LWRs program’s VUQ Focus Area.
Xue, Chuan; Brown, Anthony
2015-01-01T23:59:59.000Z
The organization of the axonal cytoskeleton is a key determinant of the normal function of an axon, which is a long thin projection away from a neuron. Under normal conditions two axonal cytoskeletal polymers microtubules and neurofilaments align longitudinally in axons and are interspersed in axonal cross-sections. However, in many neurotoxic and neurodegenerative disorders, microtubules and neurofilaments segregate apart from each other, with microtubules and membranous organelles clustered centrally and neurofilaments displaced to the periphery. This striking segregation precedes abnormal and excessive neurofilament accumulation in these diseases, which in turn leads to focal axonal swellings. While neurofilament accumulation suggests the impairment of neurofilament transport along axons, the underlying mechanism of their segregation from microtubules remains poorly understood for over 30 years. To address this question, we developed a stochastic multiscale model for the cross-sectional distribution of mic...
Cummings, Peter [Vanderbilt University] [Vanderbilt University
2009-11-15T23:59:59.000Z
The document is the final report of the DOE Computational Nanoscience Project DE-FG02-03ER46096: Integrated Multiscale Modeling of Molecular Computing Devices. It included references to 62 publications that were supported by the grant.
Luo, Jian; Tomar, Vikas; Zhou, Naixie; Lee, Hongsuk
2013-06-30T23:59:59.000Z
Based on a recent discovery of premelting-like grain boundary segregation in refractory metals occurring at high temperatures and/or high alloying levels, this project investigated grain boundary segregation and embrittlement in tungsten (W) based alloys. Specifically, new interfacial thermodynamic models have been developed and quantified to predict high-temperature grain boundary segregation in the W-Ni binary alloy and W-Ni-Fe, W-Ni-Ti, W-Ni-Co, W-Ni-Cr, W-Ni-Zr and W-Ni-Nb ternary alloys. The thermodynamic modeling results have been experimentally validated for selected systems. Furthermore, multiscale modeling has been conducted at continuum, atomistic and quantum-mechanical levels to link grain boundary segregation with embrittlement. In summary, this 3-year project has successfully developed a theoretical framework in combination with a multiscale modeling strategy for predicting grain boundary segregation and embrittlement in W based alloys.
McLaughlin, Dennis
The multiscale autoregressive (MAR) framework was introduced in the last decade to process signals that exhibit multiscale features. It provides the method for identifying the multiscale structure in signals and a filtering ...
David A. Randall; Marat Khairoutdinov
2007-12-14T23:59:59.000Z
The Colorado State University (CSU) Multi-scale Modeling Framework (MMF) is a new type of general circulation model (GCM) that replaces the conventional parameterizations of convection, clouds and boundary layer with a cloud-resolving model (CRM) embedded into each grid column. The MMF that we have been working with is a “super-parameterized” version of the Community Atmosphere Model (CAM). As reported in the publications listed below, we have done extensive work with the model. We have explored the MMF’s performance in several studies, including an AMIP run and a CAPT test, and we have applied the MMF to an analysis of climate sensitivity.
Investigating ice nucleation in cirrus clouds with an aerosol-enabled Multiscale Modeling Framework
Zhang, Chengzhu; Wang, Minghuai; Morrison, H.; Somerville, Richard C.; Zhang, Kai; Liu, Xiaohong; Li, J-L F.
2014-12-01T23:59:59.000Z
In this study, an aerosol-dependent ice nucleation scheme [Liu and Penner, 2005] has been implemented in an aerosol-enabled multi-scale modeling framework (PNNL MMF) to study ice formation in upper troposphere cirrus clouds through both homogeneous and heterogeneous nucleation. The MMF model represents cloud scale processes by embedding a cloud-resolving model (CRM) within each vertical column of a GCM grid. By explicitly linking ice nucleation to aerosol number concentration, CRM-scale temperature, relative humidity and vertical velocity, the new MMF model simulates the persistent high ice supersaturation and low ice number concentration (10 to 100/L) at cirrus temperatures. The low ice number is attributed to the dominance of heterogeneous nucleation in ice formation. The new model simulates the observed shift of the ice supersaturation PDF towards higher values at low temperatures following homogeneous nucleation threshold. The MMF models predict a higher frequency of midlatitude supersaturation in the Southern hemisphere and winter hemisphere, which is consistent with previous satellite and in-situ observations. It is shown that compared to a conventional GCM, the MMF is a more powerful model to emulate parameters that evolve over short time scales such as supersaturation. Sensitivity tests suggest that the simulated global distribution of ice clouds is sensitive to the ice nucleation schemes and the distribution of sulfate and dust aerosols. Simulations are also performed to test empirical parameters related to auto-conversion of ice crystals to snow. Results show that with a value of 250 ?m for the critical diameter, Dcs, that distinguishes ice crystals from snow, the model can produce good agreement to the satellite retrieved products in terms of cloud ice water path and ice water content, while the total ice water is not sensitive to the specification of Dcs value.
Toward Multi-scale Modeling and simulation of conduction in heterogeneous materials.
Lechman, Jeremy B.; Battaile, Corbett Chandler.; Bolintineanu, Dan; Cooper, Marcia A.; Erikson, William W.; Foiles, Stephen M.; Kay, Jeffrey J [Sandia National Laboratories, Livermore, CA; Phinney, Leslie M.; Piekos, Edward S.; Specht, Paul Elliott; Wixom, Ryan R.; Yarrington, Cole
2015-01-01T23:59:59.000Z
This report summarizes a project in which the authors sought to develop and deploy: (i) experimental techniques to elucidate the complex, multiscale nature of thermal transport in particle-based materials; and (ii) modeling approaches to address current challenges in predicting performace variability of materials (e.g., identifying and characterizing physical- chemical processes and their couplings across multiple length and time scales, modeling infor- mation transfer between scales, and statically and dynamically resolving material structure and its evolution during manufacturing and device performance). Experimentally, several capabilities were sucessfully advanced. As discussed in Chapter 2 a flash diffusivity capabil- ity for measuring homogeneous thermal conductivity of pyrotechnic powders (and beyond) was advanced; leading to enhanced characterization of pyrotechnic materials and properties impacting component development. Chapter 4 describes sucess for the first time, although preliminary, in resolving thermal fields at speeds and spatial scales relevant to energetic components. Chapter 7 summarizes the first ever (as far as the authors know) application of TDTR to actual pyrotechnic materials. This is the first attempt to actually characterize these materials at the interfacial scale. On the modeling side, new capabilities in image processing of experimental microstructures and direct numerical simulation on complicated structures were advanced (see Chapters 3 and 5). In addition, modeling work described in Chapter 8 led to improved prediction of interface thermal conductance from first principles calculations. Toward the second point, for a model system of packed particles, significant headway was made in implementing numerical algorithms and collecting data to justify the approach in terms of highlighting the phenomena at play and pointing the way forward in de- veloping and informing the kind of modeling approach oringinally envisioned (see Chapter 6). In both cases much more remains to be accomplished.
MULTI-SCALE MODELING AND APPROXIMATION ASSISTED OPTIMIZATION OF BARE TUBE HEAT EXCHANGERS
Bacellar, Daniel [University of Maryland, College Park; Ling, Jiazhen [University of Maryland, College Park; Aute, Vikrant [University of Maryland, College Park; Radermacher, Reinhard [University of Maryland, College Park; Abdelaziz, Omar [ORNL
2014-01-01T23:59:59.000Z
Air-to-refrigerant heat exchangers are very common in air-conditioning, heat pump and refrigeration applications. In these heat exchangers, there is a great benefit in terms of size, weight, refrigerant charge and heat transfer coefficient, by moving from conventional channel sizes (~ 9mm) to smaller channel sizes (< 5mm). This work investigates new designs for air-to-refrigerant heat exchangers with tube outer diameter ranging from 0.5 to 2.0mm. The goal of this research is to develop and optimize the design of these heat exchangers and compare their performance with existing state of the art designs. The air-side performance of various tube bundle configurations are analyzed using a Parallel Parameterized CFD (PPCFD) technique. PPCFD allows for fast-parametric CFD analyses of various geometries with topology change. Approximation techniques drastically reduce the number of CFD evaluations required during optimization. Maximum Entropy Design method is used for sampling and Kriging method is used for metamodeling. Metamodels are developed for the air-side heat transfer coefficients and pressure drop as a function of tube-bundle dimensions and air velocity. The metamodels are then integrated with an air-to-refrigerant heat exchanger design code. This integration allows a multi-scale analysis of air-side performance heat exchangers including air-to-refrigerant heat transfer and phase change. Overall optimization is carried out using a multi-objective genetic algorithm. The optimal designs found can exhibit 50 percent size reduction, 75 percent decrease in air side pressure drop and doubled air heat transfer coefficients compared to a high performance compact micro channel heat exchanger with same capacity and flow rates.
Reinhold H. Dauskardt
2005-08-30T23:59:59.000Z
Final technical report detailing unique experimental and multi-scale computational modeling capabilities developed to study fracture and subcritical cracking in thin-film structures. Our program to date at Stanford has studied the mechanisms of fracture and fatigue crack-growth in structural ceramics at high temperature, bulk and thin-film glasses in selected moist environments where we demonstrated the presence of a true mechanical fatigue effect in some glass compositions. We also reported on the effects of complex environments and fatigue loading on subcritical cracking that effects the reliability of MEMS and other micro-devices using novel micro-machined silicon specimens and nanomaterial layers.
Multiscale Method for Elastic Wave Propagation in the Heterogeneous, Anisotropic Media
Gao, Kai
2014-08-05T23:59:59.000Z
Seismic wave simulation in realistic Earth media with full wavefield methods is a fundamental task in geophysical studies. Conventional approaches such as the finite-difference method and the finite-element method solve ...
Multi-Scale Methods and Complex Processes: a Survey and Look Ahead
Lucia, Angelo
using multi- scale methods and often require high performance computing (clusters, supercomputers, cloud
11/13/2007 1 Multiscale Physics
; Plasma Physics Materials Science Analogies; The new kid on the block: Multiscale Modeling; A few11/13/2007 1 Multiscale Physics Challenges for Plasma- Facing Materials N.M. Ghoniem (UCLA) and B-20, 2007 Orlando, Florida #12;11/13/2007 2 Lecture Outline Research Approach and the Materials Environment
Electric field based fabrication methods for multi-scale structured surfaces
Joung, Young Soo
2014-01-01T23:59:59.000Z
Control of micro/nano scale surface structures and properties is crucial to developing novel functional materials. From an engineering point of view, the development of scalable and economical micro/nano-fabrication methods ...
Pan, Wenxiao; Fedosov, Dmitry A.; Caswell, Bruce; Karniadakis, George E.
2011-05-27T23:59:59.000Z
In this work we compare the predictive capability of two mathematical models for red blood cells (RBCs) focusing on blood flow in capillaries and arterioles. Both RBC models as well as their corresponding blood flows are based on the dissipative particle dynamics (DPD) method, a coarse-grained molecular dynamics approach. The first model employs a multiscale description of the RBC (MS-RBC), with its membrane represented by hundreds or even thousands of DPD-particles connected by springs into a triangular network in combination with out-of-plane elastic bending resistance. Extra dissipation within the network accounts for membrane viscosity, while the characteristic biconcave RBC shape is achieved by imposition of constraints for constant membrane area and constant cell volume. The second model is based on a low-dimensional description (LD-RBC) constructed as a closed torus-like ring of only 10 large DPD colloidal particles. They are connected into a ring by worm-like chain (WLC) springs combined with bending resistance. The LD-RBC model can be fitted to represent the entire range of nonlinear elastic deformations as measured by optical-tweezers for healthy and for infected RBCs in malaria. MS-RBCs suspensions model the dynamics and rheology of blood flow accurately for any size vessel but this approach is computationally expensive above 100 microns. Surprisingly, the much more economical suspensions of LD-RBCs also capture the blood flow dynamics and rheology accurately except for vessels with sizes comparable to RBC diameter. In particular, the LD-RBC suspensions are shown to properly capture the experimental data for the apparent viscosity of blood and its cell-free layer (CFL) in tube flow. Taken together, these findings suggest a hierarchical approach in modeling blood flow in the arterial tree, whereby the MS-RBC model should be employed for capillaries and arterioles below 100 microns, the LD-RBC model for arterioles, and the continuum description for arteries.
Multi-scale modelling of III-nitrides: from dislocations to the electronic structure
Holec, David
level modelling for the case of the critical thickness of thin epitaxial layers, and covers some issues of simulating the electronic structure of III-nitride alloys by means of the first principle methods. The first part of this work discusses several...
Wavelet correlations to reveal multiscale coupling in geophysical systems
Casagrande, Erik; Miralles, Diego; Entekhabi, Dara; Molini, Annalisa
2015-01-01T23:59:59.000Z
The interactions between climate and the environment are highly complex. Due to this complexity, process-based models are often preferred to estimate the net magnitude and directionality of interactions in the Earth System. However, these models are based on simplifications of our understanding of nature, thus are unavoidably imperfect. Conversely, observation-based data of climatic and environmental variables are becoming increasingly accessible over large scales due to the progress of space-borne sensing technologies and data-assimilation techniques. Albeit uncertain, these data enable the possibility to start unraveling complex multivariable, multiscale relationships if the appropriate statistical methods are applied. Here, we investigate the potential of the wavelet cross-correlation method as a tool for identifying multiscale interactions, feedback and regime shifts in geophysical systems. The ability of wavelet cross-correlation to resolve the fast and slow components of coupled systems is tested on syn...
Multiscale Simulation Framework for Coupled Fluid Flow and Mechanical Deformation
Tchelepi, Hamdi
2014-11-14T23:59:59.000Z
A multiscale linear-solver framework for the pressure equation associated with flow in highly heterogeneous porous formations was developed. The multiscale based approach is cast in a general algebraic form, which facilitates integration of the new scalable linear solver in existing flow simulators. The Algebraic Multiscale Solver (AMS) is employed as a preconditioner within a multi-stage strategy. The formulations investigated include the standard MultiScale Finite-Element (MSFE) andMultiScale Finite-Volume (MSFV) methods. The local-stage solvers include incomplete factorization and the so-called Correction Functions (CF) associated with the MSFV approach. Extensive testing of AMS, as an iterative linear solver, indicate excellent convergence rates and computational scalability. AMS compares favorably with advanced Algebraic MultiGrid (AMG) solvers for highly detailed three-dimensional heterogeneous models. Moreover, AMS is expected to be especially beneficial in solving time-dependent problems of coupled multiphase flow and transport in large-scale subsurface formations.
Multiscale modeling and characterization for performance and safety of lithium-ion batteries
Pannala, Sreekanth [ORNL; Turner, John A [ORNL; Allu, Srikanth [ORNL; Elwasif, Wael R [ORNL; Kalnaus, Sergiy [ORNL; Simunovic, Srdjan [ORNL; Kumar, Abhishek [ORNL; Billings, Jay Jay [ORNL; Wang, Hsin [ORNL; Nanda, Jagjit [ORNL
2015-01-01T23:59:59.000Z
Lithium-ion batteries are highly complex electrochemical systems whose performance and safety are governed by coupled nonlinear electrochemical-electrical-thermal-mechanical processes over a range of spatiotemporal scales. In this paper we describe a new, open source computational framework for Lithium-ion battery simulations that is designed to support a variety of model types and formulations. This framework has been used to create three-dimensional cell and battery pack models that explicitly simulate all the battery components (current collectors, electrodes, and separator). The models are used to predict battery performance under normal operations and to study thermal and mechanical safety aspects under adverse conditions. The model development and validation are supported by experimental methods such as IR-imaging, X-ray tomography and micro-Raman mapping.
with friction P.-A. Boucard1, D. Odi`evre1 and F. Gatuingt1 LMT-Cachan (ENS Cachan/CNRS/Universit´e Paris 6/PRES with friction. Our approach is based on the multiscale LATIN method with domain decomposition. This is a mixed; transient dynamics; domain decomposition; contact; friction; parallel processing 1. INTRODUCTION Modeling
Report of the First Multiscale Mathematics Workshop: First Steps toward a Roadmap
Gropp, Bill
mathematics and considerable development of computational methods and software will be required to address and engineering problems will remain out of reach for the foreseeable future. Mathematical modelingReport of the First Multiscale Mathematics Workshop: First Steps toward a Roadmap #12
Grell, Georg; Fast, Jerome D.; Gustafson, William I.; Peckham, Steven E.; McKeen, Stuart A.; Salzmann, Marc; Freitas, Saulo
2010-01-01T23:59:59.000Z
This is a conference proceeding that is now being put together as a book. This is chapter 2 of the book: "INTEGRATED SYSTEMS OF MESO-METEOROLOGICAL AND CHEMICAL TRANSPORT MODELS" published by Springer. The chapter title is "On-line Chemistry within WRF: Description and Evaluation of a State-of-the-Art Multiscale Air Quality and Weather Prediction Model." The original conference was the COST-728/NetFAM workshop on Integrated systems of meso-meteorological and chemical transport models, Danish Meteorological Institute, Copenhagen, May 21-23, 2007.
Pritchard, Michael Stephen
2011-01-01T23:59:59.000Z
their Community Earth System Model (Richard Neale, personaldevelopment of Earth system models capable of reproducing
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)
2013-07-01T23:59:59.000Z
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.
MULTISCALE PHENOMENA IN MATERIALS
A. BISHOP
2000-09-01T23:59:59.000Z
This project developed and supported a technology base in nonequilibrium phenomena underpinning fundamental issues in condensed matter and materials science, and applied this technology to selected problems. In this way the increasingly sophisticated synthesis and characterization available for classes of complex electronic and structural materials provided a testbed for nonlinear science, while nonlinear and nonequilibrium techniques helped advance our understanding of the scientific principles underlying the control of material microstructure, their evolution, fundamental to macroscopic functionalities. The project focused on overlapping areas of emerging thrusts and programs in the Los Alamos materials community for which nonlinear and nonequilibrium approaches will have decisive roles and where productive teamwork among elements of modeling, simulations, synthesis, characterization and applications could be anticipated--particularly multiscale and nonequilibrium phenomena, and complex matter in and between fields of soft, hard and biomimetic materials. Principal topics were: (i) Complex organic and inorganic electronic materials, including hard, soft and biomimetic materials, self-assembly processes and photophysics; (ii) Microstructure and evolution in multiscale and hierarchical materials, including dynamic fracture and friction, dislocation and large-scale deformation, metastability, and inhomogeneity; and (iii) Equilibrium and nonequilibrium phases and phase transformations, emphasizing competing interactions, frustration, landscapes, glassy and stochastic dynamics, and energy focusing.
A SIMPLE CLOSURE APPROXIMATION FOR SLOW DYNAMICS OF A MULTISCALE SYSTEM: NONLINEAR AND
Abramov, Rafail
A SIMPLE CLOSURE APPROXIMATION FOR SLOW DYNAMICS OF A MULTISCALE SYSTEM: NONLINEAR response, multiscale systems, nonlinear coupling AMS subject classifications. 37M, 37N 1. Introduction slow and fast variables of the system. Many closure methods were designed for multiscale dynamical
Freed, Alan D.; Einstein, Daniel R.; Carson, James P.; Jacob, Rick E.
2012-03-01T23:59:59.000Z
In the first year of this contractual effort a hypo-elastic constitutive model was developed and shown to have great potential in modeling the elastic response of parenchyma. This model resides at the macroscopic level of the continuum. In this, the second year of our support, an isotropic dodecahedron is employed as an alveolar model. This is a microscopic model for parenchyma. A hopeful outcome is that the linkage between these two scales of modeling will be a source of insight and inspiration that will aid us in the final year's activity: creating a viscoelastic model for parenchyma.
Multiscale Reservoir Simulation: Layer Design, Full Field Pseudoization and Near Well Modeling
Du, Song
2012-12-10T23:59:59.000Z
In the past decades, considerable effort has been put into developing high resolution geological models for oil and gas reservoirs. Although the growth of computational power is rapid, the static model size still exceeds the model size for routine...
Ortiz, Michael
ENRICHMENT WITH APPLICATION TO SINGLE-CRYSTAL PLASTICITY SERGIO CONTI, PATRICE HAURET, AND MICHAEL ORTIZ, single-crystal plasticity, for which the explicit relaxation of the problem is derived analytically words. multiscale computing, relaxation, microstructure, finite elements, enhanced strain, single-crystal
Modeling, Analysis and Simulation of Multiscale Preferential Flow - 8/05-8/10 - Final Report
Ralph Showalter; Malgorzata Peszynska
2012-07-03T23:59:59.000Z
The research agenda of this project are: (1) Modeling of preferential transport from mesoscale to macroscale; (2) Modeling of fast flow in narrow fractures in porous media; (3) Pseudo-parabolic Models of Dynamic Capillary Pressure; (4) Adaptive computational upscaling of flow with inertia from porescale to mesoscale; (5) Adaptive modeling of nonlinear coupled systems; and (6) Adaptive modeling and a-posteriori estimators for coupled systems with heterogeneous data.
Evaluation of the Multi-Scale Modeling Framework using Data from...
Office of Scientific and Technical Information (OSTI)
Measurement (ARM) program was to provide long-term observations for evaluation of cloud and radiation treatment in global climate models. Unfortunately, traditional...
Watt-Sun: A Multi-Scale, Multi-Model, Machine-Learning Solar...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
proposed technology will leverage deep machine learning and self-adjusting voting algorithms to decide between various forecasting models and expert systems. This approach will...
The Radiative Properties of Small Clouds: Multi-Scale Observations and Modeling
Feingold, Graham [NOAA ESRL; McComiskey, Allison [CIRES, University of Colorado
2013-09-25T23:59:59.000Z
Warm, liquid clouds and their representation in climate models continue to represent one of the most significant unknowns in climate sensitivity and climate change. Our project combines ARM observations, LES modeling, and satellite imagery to characterize shallow clouds and the role of aerosol in modifying their radiative effects.
MULTI-SCALE MODELLING USING 3-DIMENSIONAL ADAPTIVE MESHING WITH AN IMPLICIT, MULTIGRID SOLVER: A
Jimack, Peter
Research1 and School of Computing2 , University of Leeds, Leeds LS2-9JT, UK. Keywords: Phase-Field, Dendritic Growth, Mesh Adaptivity, Multigrid Methods. Abstract We review the application of advanced
PublishedbyManeyPublishing(c)IOMCommunicationsLtd Novel approaches to multiscale modelling in
Elliott, James
in brittle solids, polymer chain relaxation in nanocomposites and the control of nucleation in biomimetic, Monte Carlo, Finite element analysis, Hierarchical/hybrid models, Density functional theory, Review List
A multi-scale iterative approach for finite element modeling of thermal contact resistance
Thompson, Mary Kathryn, 1980-
2007-01-01T23:59:59.000Z
Surface topography has long been considered a key factor in the performance of many contact applications including thermal contact resistance. However, essentially all analytical and numerical models of thermal contact ...
Sheng, Nuo, 1977-
2006-01-01T23:59:59.000Z
Polymer/clay nanocomposites have been observed to exhibit enhanced thermal/mechanical properties at low weight fractions (We) of clay. Continuum-based composite modeling reveals that the enhanced properties are strongly ...
Parallel multiscale simulations of a brain aneurysm
Grinberg, Leopold [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States)] [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States); Fedosov, Dmitry A. [Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, Jülich 52425 (Germany)] [Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, Jülich 52425 (Germany); Karniadakis, George Em, E-mail: george_karniadakis@brown.edu [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States)
2013-07-01T23:59:59.000Z
Cardiovascular pathologies, such as a brain aneurysm, are affected by the global blood circulation as well as by the local microrheology. Hence, developing computational models for such cases requires the coupling of disparate spatial and temporal scales often governed by diverse mathematical descriptions, e.g., by partial differential equations (continuum) and ordinary differential equations for discrete particles (atomistic). However, interfacing atomistic-based with continuum-based domain discretizations is a challenging problem that requires both mathematical and computational advances. We present here a hybrid methodology that enabled us to perform the first multiscale simulations of platelet depositions on the wall of a brain aneurysm. The large scale flow features in the intracranial network are accurately resolved by using the high-order spectral element Navier–Stokes solver N??T?r. The blood rheology inside the aneurysm is modeled using a coarse-grained stochastic molecular dynamics approach (the dissipative particle dynamics method) implemented in the parallel code LAMMPS. The continuum and atomistic domains overlap with interface conditions provided by effective forces computed adaptively to ensure continuity of states across the interface boundary. A two-way interaction is allowed with the time-evolving boundary of the (deposited) platelet clusters tracked by an immersed boundary method. The corresponding heterogeneous solvers (N??T?r and LAMMPS) are linked together by a computational multilevel message passing interface that facilitates modularity and high parallel efficiency. Results of multiscale simulations of clot formation inside the aneurysm in a patient-specific arterial tree are presented. We also discuss the computational challenges involved and present scalability results of our coupled solver on up to 300 K computer processors. Validation of such coupled atomistic-continuum models is a main open issue that has to be addressed in future work.
SMART: A Stochastic Multiscale Model for the Analysis of Energy Resources, Technology and Policy
Powell, Warren B.
-use strategies (level of demand, demand response). A major component will be renewable energy that depend from wind, demands, prices and rainfall. We also wish to model long-term investment decisions demonstrate the methodology using both spatially aggregate and disaggregate representations of energy supply
2005-01-2962 Multi-scale modeling of advanced life support systems
Kortenkamp, David
hybrid (continuous/discrete) physical system modeling at the sub-system level. INTRODUCTION Advanced Life-systems that can be hierarchically refined to their underlying physical components, such as electric motors, pumps, compressors, valves, and heat exchangers. The design of advanced control architectures also depends critically
Global and multi-scale features of solar wind-magnetosphere coupling: From modeling to forecasting
Sitnov, Mikhail I.
with the AL index, which measures the magnetic field disturbances produced by the substorm current system, such as turbulence, bursty bulk flows [Angelopolous et. al., 1999], and fluctuations in the near-Earth current sheet to reconstruct behavior of the system independent of modeling assump- tions, long time series data of geomagnetic
Understanding Creep Mechanisms in Graphite with Experiments, Multiscale Simulations, and Modeling
Eapen, Jacob; Murty, Korukonda; Burchell, Timothy
2014-06-02T23:59:59.000Z
Disordering mechanisms in graphite have a long history with conflicting viewpoints. Using Raman and x-ray photon spectroscopy, electron microscopy, x-ray diffraction experiments and atomistic modeling and simulations, the current project has developed a fundamental understanding of early-to-late state radiation damage mechanisms in nuclear reactor grade graphite (NBG-18 and PCEA). We show that the topological defects in graphite play an important role under neutron and ion irradiation.
Multi-scale Modeling Approach to Acoustic Emission during Plastic Deformation
Jagadish Kumar; G. Ananthakrishna
2011-02-20T23:59:59.000Z
We address the long standing problem of the origin of acoustic emission commonly observed during plastic deformation. We propose a frame-work to deal with the widely separated time scales of collective dislocation dynamics and elastic degrees of freedom to explain the nature of acoustic emission observed during the Portevin-Le Chatelier effect. The Ananthakrishna model is used as it explains most generic features of the phenomenon. Our results show that while acoustic emission bursts correlated with stress drops are well separated for the type C serrations, these bursts merge to form nearly continuous acoustic signals with overriding bursts for the propagating type A bands.
A Hybrid Multiscale Framework for Subsurface Flow and Transport Simulations
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Scheibe, Timothy D.; Yang, Xiaofan; Chen, Xingyuan; Hammond, Glenn E.
2015-06-01T23:59:59.000Z
Extensive research efforts have been invested in reducing model errors to improve the predictive ability of biogeochemical earth and environmental system simulators, with applications ranging from contaminant transport and remediation to impacts of biogeochemical elemental cycling (e.g., carbon and nitrogen) on local ecosystems and regional to global climate. While the bulk of this research has focused on improving model parameterizations in the face of observational limitations, the more challenging type of model error/uncertainty to identify and quantify is model structural error which arises from incorrect mathematical representations of (or failure to consider) important physical, chemical, or biological processes, properties, ormore »system states in model formulations. While improved process understanding can be achieved through scientific study, such understanding is usually developed at small scales. Process-based numerical models are typically designed for a particular characteristic length and time scale. For application-relevant scales, it is generally necessary to introduce approximations and empirical parameterizations to describe complex systems or processes. This single-scale approach has been the best available to date because of limited understanding of process coupling combined with practical limitations on system characterization and computation. While computational power is increasing significantly and our understanding of biological and environmental processes at fundamental scales is accelerating, using this information to advance our knowledge of the larger system behavior requires the development of multiscale simulators. Accordingly there has been much recent interest in novel multiscale methods in which microscale and macroscale models are explicitly coupled in a single hybrid multiscale simulation. A limited number of hybrid multiscale simulations have been developed for biogeochemical earth systems, but they mostly utilize application-specific and sometimes ad-hoc approaches for model coupling. We are developing a generalized approach to hierarchical model coupling designed for high-performance computational systems, based on the Swift computing workflow framework. In this presentation we will describe the generalized approach and provide two use cases: 1) simulation of a mixing-controlled biogeochemical reaction coupling pore- and continuum-scale models, and 2) simulation of biogeochemical impacts of groundwater – river water interactions coupling fine- and coarse-grid model representations. This generalized framework can be customized for use with any pair of linked models (microscale and macroscale) with minimal intrusiveness to the at-scale simulators. It combines a set of python scripts with the Swift workflow environment to execute a complex multiscale simulation utilizing an approach similar to the well-known Heterogeneous Multiscale Method. User customization is facilitated through user-provided input and output file templates and processing function scripts, and execution within a high-performance computing environment is handled by Swift, such that minimal to no user modification of at-scale codes is required.« less
A Hybrid Multiscale Framework for Subsurface Flow and Transport Simulations
Scheibe, Timothy D.; Yang, Xiaofan; Chen, Xingyuan; Hammond, Glenn E.
2015-01-01T23:59:59.000Z
Extensive research efforts have been invested in reducing model errors to improve the predictive ability of biogeochemical earth and environmental system simulators, with applications ranging from contaminant transport and remediation to impacts of biogeochemical elemental cycling (e.g., carbon and nitrogen) on local ecosystems and regional to global climate. While the bulk of this research has focused on improving model parameterizations in the face of observational limitations, the more challenging type of model error/uncertainty to identify and quantify is model structural error which arises from incorrect mathematical representations of (or failure to consider) important physical, chemical, or biological processes, properties, or system states in model formulations. While improved process understanding can be achieved through scientific study, such understanding is usually developed at small scales. Process-based numerical models are typically designed for a particular characteristic length and time scale. For application-relevant scales, it is generally necessary to introduce approximations and empirical parameterizations to describe complex systems or processes. This single-scale approach has been the best available to date because of limited understanding of process coupling combined with practical limitations on system characterization and computation. While computational power is increasing significantly and our understanding of biological and environmental processes at fundamental scales is accelerating, using this information to advance our knowledge of the larger system behavior requires the development of multiscale simulators. Accordingly there has been much recent interest in novel multiscale methods in which microscale and macroscale models are explicitly coupled in a single hybrid multiscale simulation. A limited number of hybrid multiscale simulations have been developed for biogeochemical earth systems, but they mostly utilize application-specific and sometimes ad-hoc approaches for model coupling. We are developing a generalized approach to hierarchical model coupling designed for high-performance computational systems, based on the Swift computing workflow framework. In this presentation we will describe the generalized approach and provide two use cases: 1) simulation of a mixing-controlled biogeochemical reaction coupling pore- and continuum-scale models, and 2) simulation of biogeochemical impacts of groundwater – river water interactions coupling fine- and coarse-grid model representations. This generalized framework can be customized for use with any pair of linked models (microscale and macroscale) with minimal intrusiveness to the at-scale simulators. It combines a set of python scripts with the Swift workflow environment to execute a complex multiscale simulation utilizing an approach similar to the well-known Heterogeneous Multiscale Method. User customization is facilitated through user-provided input and output file templates and processing function scripts, and execution within a high-performance computing environment is handled by Swift, such that minimal to no user modification of at-scale codes is required.
Hydraulic Fracture: multiscale processes and moving
Peirce, Anthony
Hydraulic Fracture: multiscale processes and moving interfaces Anthony Peirce Department Siebrits (SLB, Houston) #12;2 Outline · What is a hydraulic fracture? · Mathematical models of hydraulic and physical processes Fracture Energy Breaking rock Leak-off Viscous energy loss #12;8 Scaling
Image Analysis Model-Based Methods
Wolfe, Patrick J.
Model-Based Methods Comparing and Evaluating Models Summary Further Reading Data Collection ScientificImage Analysis Model-Based Methods Comparing and Evaluating Models Summary Further Reading Fully Low-Count Image Analysis #12;Image Analysis Model-Based Methods Comparing and Evaluating Models
Niyogi, Devdutta S. [Purdue
2013-06-07T23:59:59.000Z
The CLASIC experiment was conducted over the US southern great plains (SGP) in June 2007 with an objective to lead an enhanced understanding of the cumulus convection particularly as it relates to land surface conditions. This project was design to help assist with understanding the overall improvement of land atmosphere convection initiation representation of which is important for global and regional models. The study helped address one of the critical documented deficiency in the models central to the ARM objectives for cumulus convection initiation and particularly under summer time conditions. This project was guided by the scientific question building on the CLASIC theme questions: What is the effect of improved land surface representation on the ability of coupled models to simulate cumulus and convection initiation? The focus was on the US Southern Great Plains region. Since the CLASIC period was anomalously wet the strategy has been to use other periods and domains to develop the comparative assessment for the CLASIC data period, and to understand the mechanisms of the anomalous wet conditions on the tropical systems and convection over land. The data periods include the IHOP 2002 field experiment that was over roughly same domain as the CLASIC in the SGP, and some of the DOE funded Ameriflux datasets.
Kwon, Joseph Sangil
2015-01-01T23:59:59.000Z
A. Ha. On-line process optimization and control using theA. Varshney. Control and Optimization of Multiscale Processprocesses can be found in [23]. Remark 5.4 The proposed optimization/control
Identifying overlapping communities in social networks using multi-scale local information expansion
Li, Hui-Jia; Liu, Zhi-Ping; Chen, Luonan; Zhang, Xiang-Sun
2015-01-01T23:59:59.000Z
Most existing approaches for community detection require complete information of the graph in a specific scale, which is impractical for many social networks. We propose a novel algorithm that does not embrace the universal approach but instead of trying to focus on local social ties and modeling multi-scales of social interactions occurring in those networks. Our method for the first time optimizes the topological entropy of a network and uncovers communities through a novel dynamic system converging to a local minimum by simply updating the membership vector with very low computational complexity. It naturally supports overlapping communities through associating each node with a membership vector which describes node's involvement in each community. This way, in addition to uncover overlapping communities, we can also describe different multi-scale partitions by tuning the characteristic size of modules from the optimal partition. Because of the high efficiency and accuracy of the algorithm, it is feasible ...
MULTISCALE MATHEMATICS FOR BIOMASS CONVERSION TO RENEWABLE HYDROGEN
Vlachos, Dionisios; Plechac, Petr; Katsoulakis, Markos
2013-09-05T23:59:59.000Z
The overall objective of this project is to develop multiscale models for understanding and eventually designing complex processes for renewables. To the best of our knowledge, our work is the first attempt at modeling complex reacting systems, whose performance relies on underlying multiscale mathematics. Our specific application lies at the heart of biofuels initiatives of DOE and entails modeling of catalytic systems, to enable economic, environmentally benign, and efficient conversion of biomass into either hydrogen or valuable chemicals. Specific goals include: (i) Development of rigorous spatio-temporal coarse-grained kinetic Monte Carlo (KMC) mathematics and simulation for microscopic processes encountered in biomass transformation. (ii) Development of hybrid multiscale simulation that links stochastic simulation to a deterministic partial differential equation (PDE) model for an entire reactor. (iii) Development of hybrid multiscale simulation that links KMC simulation with quantum density functional theory (DFT) calculations. (iv) Development of parallelization of models of (i)-(iii) to take advantage of Petaflop computing and enable real world applications of complex, multiscale models. In this NCE period, we continued addressing these objectives and completed the proposed work. Main initiatives, key results, and activities are outlined.
Dudhia, Jimy
2013-03-12T23:59:59.000Z
Clouds in the tropical western Pacific are an integral part of the large scale environment. An improved understanding of the multi-scale structure of clouds and their interactions with the environment is critical to the ARM (Atmospheric Radiation Measurement) program for developing and evaluating cloud parameterizations, understanding the consequences of model biases, and providing a context for interpreting the observational data collected over the ARM Tropical Western Pacific (TWP) sites. Three-dimensional cloud resolving models (CRMs) are powerful tools for developing and evaluating cloud parameterizations. However, a significant challenge in using CRMs in the TWP is that the region lacks conventional data, so large uncertainty exists in defining the large-scale environment for clouds. This project links several aspects of the ARM program, from measurements to providing improved analyses, and from cloud-resolving modeling to climate-scale modeling and parameterization development, with the overall objective to improve the representations of clouds in climate models and to simulate and quantify resolved cloud effects on the large-scale environment. Our objectives will be achieved through a series of tasks focusing on the use of the Weather Research and Forecasting (WRF) model and ARM data. Our approach includes: -- Perform assimilation of COSMIC GPS radio occultation and other satellites products using the WRF Ensemble Kalman Filter assimilation system to represent the tropical large-scale environment at 36 km grid resolution. This high-resolution analysis can be used by the community to derive forcing products for single-column models or cloud-resolving models. -- Perform cloud-resolving simulations using WRF and its nesting capabilities, driven by the improved regional analysis and evaluate the simulations against ARM datasets such as from TWP-ICE to optimize the microphysics parameters for this region. A cirrus study (Mace and co-authors) already exists for TWP-ICE using satellite and ground-based observations. -- Perform numerical experiments using WRF to investigate how convection over tropical islands in the Maritime Continent interacts with large-scale circulation and affects convection in nearby regions. -- Evaluate and apply WRF as a testbed for GCM cloud parameterizations, utilizing the ability of WRF to run on multiple scales (from cloud resolving to global) to isolate resolution and physics issues from dynamical and model framework issues. Key products will be disseminated to the ARM and larger community through distribution of data archives, including model outputs from the data assimilation products and cloud resolving simulations, and publications.
Tang Shaojie; Tang Xiangyang [Imaging and Medical Physics, Department of Radiology and Imaging Sciences, Emory University School of Medicine, 1701 Uppergate Dr., C-5018, Atlanta, Georgia 30322 (United States); School of Automation, Xi'an University of Posts and Telecommunications, Xi'an, Shaanxi 710121 (China); Imaging and Medical Physics, Department of Radiology and Imaging Sciences, Emory University School of Medicine, 1701 Uppergate Dr., C-5018, Atlanta, Georgia 30322 (United States)
2012-09-15T23:59:59.000Z
Purposes: The suppression of noise in x-ray computed tomography (CT) imaging is of clinical relevance for diagnostic image quality and the potential for radiation dose saving. Toward this purpose, statistical noise reduction methods in either the image or projection domain have been proposed, which employ a multiscale decomposition to enhance the performance of noise suppression while maintaining image sharpness. Recognizing the advantages of noise suppression in the projection domain, the authors propose a projection domain multiscale penalized weighted least squares (PWLS) method, in which the angular sampling rate is explicitly taken into consideration to account for the possible variation of interview sampling rate in advanced clinical or preclinical applications. Methods: The projection domain multiscale PWLS method is derived by converting an isotropic diffusion partial differential equation in the image domain into the projection domain, wherein a multiscale decomposition is carried out. With adoption of the Markov random field or soft thresholding objective function, the projection domain multiscale PWLS method deals with noise at each scale. To compensate for the degradation in image sharpness caused by the projection domain multiscale PWLS method, an edge enhancement is carried out following the noise reduction. The performance of the proposed method is experimentally evaluated and verified using the projection data simulated by computer and acquired by a CT scanner. Results: The preliminary results show that the proposed projection domain multiscale PWLS method outperforms the projection domain single-scale PWLS method and the image domain multiscale anisotropic diffusion method in noise reduction. In addition, the proposed method can preserve image sharpness very well while the occurrence of 'salt-and-pepper' noise and mosaic artifacts can be avoided. Conclusions: Since the interview sampling rate is taken into account in the projection domain multiscale decomposition, the proposed method is anticipated to be useful in advanced clinical and preclinical applications where the interview sampling rate varies.
Sengupta, Arkaprabha
2010-01-01T23:59:59.000Z
Phase transformation in Nitinol polycrystals 3.1 Martensiticvector pairs (m ? , b ? ) for Nitinol . . . . . . . . . . .4 Constitutive model of Nitinol 4.1 Constitutive models for
Lushnikov, Pavel
with differential adhesion and shape fluctuations is a cellular Potts model CPM which is an extension of the well-known Potts model from statistical mechanics 12,13 . In this model each bio- logical cell is represented model to a continuous description Mark Alber,1, * Nan Chen,1 Tilmann Glimm,2 and Pavel M. Lushnikov1,3 1
Ivan Jane?ek; Tomáš Jan?a; Pavel Naar; Frederic Renard; René Kalus; Florent X. Gadéa
2012-03-08T23:59:59.000Z
In this supplementary material, we recollect, for reader's convenience, the general scheme of suggested multiscale model (Sec. 1), and basic informations about approaches used for pilot study: a detailed description of the interaction model (Sec. 2) and dynamical methods used for the dark dynamics step (Sec. 3) reported previously in two preceding studies [1, 2]. In addition, a detailed description of the treatment of radiative processes is also given (Sec. 4).
Jane?ek, Ivan; Naar, Pavel; Renard, Frederic; Kalus, René; Gadéa, Florent X
2012-01-01T23:59:59.000Z
In this supplementary material, we recollect, for reader's convenience, the general scheme of suggested multiscale model (Sec. 1), and basic informations about approaches used for pilot study: a detailed description of the interaction model (Sec. 2) and dynamical methods used for the dark dynamics step (Sec. 3) reported previously in two preceding studies [1, 2]. In addition, a detailed description of the treatment of radiative processes is also given (Sec. 4).
A Many-Task Parallel Approach for Multiscale Simulations of Subsurface Flow and Reactive Transport
Scheibe, Timothy D.; Yang, Xiaofan; Schuchardt, Karen L.; Agarwal, Khushbu; Chase, Jared M.; Palmer, Bruce J.; Tartakovsky, Alexandre M.
2014-12-16T23:59:59.000Z
Continuum-scale models have long been used to study subsurface flow, transport, and reactions but lack the ability to resolve processes that are governed by pore-scale mixing. Recently, pore-scale models, which explicitly resolve individual pores and soil grains, have been developed to more accurately model pore-scale phenomena, particularly reaction processes that are controlled by local mixing. However, pore-scale models are prohibitively expensive for modeling application-scale domains. This motivates the use of a hybrid multiscale approach in which continuum- and pore-scale codes are coupled either hierarchically or concurrently within an overall simulation domain (time and space). This approach is naturally suited to an adaptive, loosely-coupled many-task methodology with three potential levels of concurrency. Each individual code (pore- and continuum-scale) can be implemented in parallel; multiple semi-independent instances of the pore-scale code are required at each time step providing a second level of concurrency; and Monte Carlo simulations of the overall system to represent uncertainty in material property distributions provide a third level of concurrency. We have developed a hybrid multiscale model of a mixing-controlled reaction in a porous medium wherein the reaction occurs only over a limited portion of the domain. Loose, minimally-invasive coupling of pre-existing parallel continuum- and pore-scale codes has been accomplished by an adaptive script-based workflow implemented in the Swift workflow system. We describe here the methods used to create the model system, adaptively control multiple coupled instances of pore- and continuum-scale simulations, and maximize the scalability of the overall system. We present results of numerical experiments conducted on NERSC supercomputing systems; our results demonstrate that loose many-task coupling provides a scalable solution for multiscale subsurface simulations with minimal overhead.
Testing a method for modelling pronunciation variation.
Kessens, Judith M; Wester, Mirjam; Cucchiarini, Catia; Strik, Helmer
1997-01-01T23:59:59.000Z
In this paper we describe a method for improving the performance of a continuous speech recognizer by modelling pronunciation variation. Although the results obtained with this method are in line with those reported by ...
Individual-specific multi-scale finite element simulation of cortical bone of human proximal femur
Ascenzi, Maria-Grazia, E-mail: mgascenzi@mednet.ucla.edu [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States)] [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States); Kawas, Neal P., E-mail: nealkawas@ucla.edu [UCLA/Orthopaedic Hospital, Department of Orthopaedic Surgery, Rehabilitation Bldg, Room 22-69, 1000 Veteran Avenue, University of California, Los Angeles, CA 90095 (United States); Lutz, Andre, E-mail: andre.lutz@hotmail.de [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany)] [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany); Kardas, Dieter, E-mail: kardas@ibnm.uni-hannover.de [ContiTech Vibration Control, Jaedekamp 30 None, 30419 Hannover (Germany)] [ContiTech Vibration Control, Jaedekamp 30 None, 30419 Hannover (Germany); Nackenhorst, Udo, E-mail: nackenhorst@ibnm.uni-hannover.de [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany)] [Institute of Biomechanics and Numerical Mechanics, Leibniz University Hannover, 30167 Hannover (Germany); Keyak, Joyce H., E-mail: jhkeyak@uci.edu [Department of Radiological Sciences, Medical Sciences I, Bldg 811, Room B140, University of California, Irvine, CA 92697-5000 (United States)
2013-07-01T23:59:59.000Z
We present an innovative method to perform multi-scale finite element analyses of the cortical component of the femur using the individual’s (1) computed tomography scan; and (2) a bone specimen obtained in conjunction with orthopedic surgery. The method enables study of micro-structural characteristics regulating strains and stresses under physiological loading conditions. The analysis of the micro-structural scenarios that cause variation of strain and stress is the first step in understanding the elevated strains and stresses in bone tissue, which are indicative of higher likelihood of micro-crack formation in bone, implicated in consequent remodeling or macroscopic bone fracture. Evidence that micro-structure varies with clinical history and contributes in significant, but poorly understood, ways to bone function, motivates the method’s development, as does need for software tools to investigate relationships between macroscopic loading and micro-structure. Three applications – varying region of interest, bone mineral density, and orientation of collagen type I, illustrate the method. We show, in comparison between physiological loading and simple compression of a patient’s femur, that strains computed at the multi-scale model’s micro-level: (i) differ; and (ii) depend on local collagen-apatite orientation and degree of calcification. Our findings confirm the strain concentration role of osteocyte lacunae, important for mechano-transduction. We hypothesize occurrence of micro-crack formation, leading either to remodeling or macroscopic fracture, when the computed strains exceed the elastic range observed in micro-structural testing.
Multi-Scale Multi-Dimensional Li-Ion Battery Model for Better Design and Management (Presentation)
Kim, G.-H.; Smith, K.
2008-10-01T23:59:59.000Z
The developed model used is to provide a better understanding and help answer engineering questions about improving the design, operational strategy, management, and safety of cells.
Multiscale Universal Interface: A Concurrent Framework for Coupling Heterogeneous Solvers
Tang, Yu-Hang; Bian, Xin; Li, Zhen; Karniadakis, George E
2014-01-01T23:59:59.000Z
Concurrently coupled numerical simulations using heterogeneous solvers are powerful tools for modeling multiscale phenomena. However, major modifications to existing codes are often required to enable such simulations, posing significant difficulties in practice. In this paper we present a C++ library, i.e. the Multiscale Universal Interface (MUI), which is capable of facilitating the coupling effort for a wide range of multiscale simulations. The library adopts a header-only form with minimal external dependency and hence can be easily dropped into existing codes. A data sampler concept is introduced, combined with a hybrid dynamic/static typing mechanism, to create an easily customizable framework for solver-independent data interpretation. The library integrates MPI MPMD support and an asynchronous communication protocol to handle inter-solver information exchange irrespective of the solvers' own MPI awareness. Template metaprogramming is heavily employed to simultaneously improve runtime performance and c...
Carter, Emily A.
prediction of dislocation nucleation and the effects of varying alloy composition. The model is illustrated and Department of Mechanical and Aerospace Engineering, D404A Engineering Quadrangle, Princeton, NJ 08544 (eac
Probabilistic Methods for Model Validation
Halder, Abhishek
2014-05-01T23:59:59.000Z
Instead of Moments or Sets . . . . . 6 1.3.4 Methodology and Organization . . . . . . . . . . . . . . . . . 8 1.4 Contributions of This Dissertation . . . . . . . . . . . . . . . . . . . . 9 2. UNCERTAINTY PROPAGATION FOR DETERMINISTIC FLOW . . . . 12 2...’s Density Function Based Model Fal- sification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 4.6 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 xv 5. CASE STUDY: F-16 CONTROLLER ROBUSTNESS VERIFICATION...
Multiscale Analysis and Optimisation of Photosynthetic Solar Energy Systems
Andrew K. Ringsmuth
2014-02-24T23:59:59.000Z
This work asks how light harvesting in photosynthetic systems can be optimised for economically scalable, sustainable energy production. Hierarchy theory is introduced as a system-analysis and optimisation tool better able to handle multiscale, multiprocess complexities in photosynthetic energetics compared with standard linear-process analysis. Within this framework, new insights are given into relationships between composition, structure and energetics at the scale of the thylakoid membrane, and also into how components at different scales cooperate under functional objectives of the whole photosynthetic system. Combining these reductionistic and holistic analyses creates a platform for modelling multiscale-optimal, idealised photosynthetic systems in silico.
Multiscale Analysis and Optimisation of Photosynthetic Solar Energy Systems
Ringsmuth, Andrew K
2014-01-01T23:59:59.000Z
This work asks how light harvesting in photosynthetic systems can be optimised for economically scalable, sustainable energy production. Hierarchy theory is introduced as a system-analysis and optimisation tool better able to handle multiscale, multiprocess complexities in photosynthetic energetics compared with standard linear-process analysis. Within this framework, new insights are given into relationships between composition, structure and energetics at the scale of the thylakoid membrane, and also into how components at different scales cooperate under functional objectives of the whole photosynthetic system. Combining these reductionistic and holistic analyses creates a platform for modelling multiscale-optimal, idealised photosynthetic systems in silico.
Morin, Jeffrey W. (Jeffrey William)
2011-01-01T23:59:59.000Z
Multi-scale surface interaction methods have been studied to achieve optimal locomotion over surface features of differing length scales. It has been shown that anisotropy is a convenient way of transferring an undirected ...
Unraveling the 3D genome: genomics tools for multiscale exploration
Straight, Aaron
Unraveling the 3D genome: genomics tools for multiscale exploration Viviana I. Risca and William J genome and the roles it may play in regulating transcription. Here we review core methods and new tools-scale chromosomal domains, and discuss the emerging pic- ture of the 3D genome that these tools have revealed. Blind
Peridynamics as a rigorous coarse-graining of atomistics for multiscale materials design.
Lehoucq, Richard B.; Aidun, John Bahram; Silling, Stewart Andrew; Sears, Mark P.; Kamm, James R.; Parks, Michael L.
2010-09-01T23:59:59.000Z
This report summarizes activities undertaken during FY08-FY10 for the LDRD Peridynamics as a Rigorous Coarse-Graining of Atomistics for Multiscale Materials Design. The goal of our project was to develop a coarse-graining of finite temperature molecular dynamics (MD) that successfully transitions from statistical mechanics to continuum mechanics. The goal of our project is to develop a coarse-graining of finite temperature molecular dynamics (MD) that successfully transitions from statistical mechanics to continuum mechanics. Our coarse-graining overcomes the intrinsic limitation of coupling atomistics with classical continuum mechanics via the FEM (finite element method), SPH (smoothed particle hydrodynamics), or MPM (material point method); namely, that classical continuum mechanics assumes a local force interaction that is incompatible with the nonlocal force model of atomistic methods. Therefore FEM, SPH, and MPM inherit this limitation. This seemingly innocuous dichotomy has far reaching consequences; for example, classical continuum mechanics cannot resolve the short wavelength behavior associated with atomistics. Other consequences include spurious forces, invalid phonon dispersion relationships, and irreconcilable descriptions/treatments of temperature. We propose a statistically based coarse-graining of atomistics via peridynamics and so develop a first of a kind mesoscopic capability to enable consistent, thermodynamically sound, atomistic-to-continuum (AtC) multiscale material simulation. Peridynamics (PD) is a microcontinuum theory that assumes nonlocal forces for describing long-range material interaction. The force interactions occurring at finite distances are naturally accounted for in PD. Moreover, PDs nonlocal force model is entirely consistent with those used by atomistics methods, in stark contrast to classical continuum mechanics. Hence, PD can be employed for mesoscopic phenomena that are beyond the realms of classical continuum mechanics and atomistic simulations, e.g., molecular dynamics and density functional theory (DFT). The latter two atomistic techniques are handicapped by the onerous length and time scales associated with simulating mesoscopic materials. Simulating such mesoscopic materials is likely to require, and greatly benefit from multiscale simulations coupling DFT, MD, PD, and explicit transient dynamic finite element methods FEM (e.g., Presto). The proposed work fills the gap needed to enable multiscale materials simulations.
Multiscale modeling of the brittle to ductile transition S.J. Noronha, J. Huang, N.M. Ghoniem *
Ghoniem, Nasr M.
zone is represented as an array of discrete dislocations emitted from crack-tip sources. In their model they equated the competing forces acting on a dislocation near the crack-tip, and derived material parameters, the surface en- ergy (c) and the unstable stacking fault energy (cus) [2
Multiscale Metrology and Optimization of Ultra-Scaled InAs Quantum Well FETs
Kharche, Neerav
A simulation methodology for ultra-scaled InAs quantum well field-effect transistors (QWFETs) is presented and used to provide design guidelines and a path to improve device performance. A multiscale modeling approach is ...
Ravikumar, Rahul
2009-05-15T23:59:59.000Z
to texture information extraction and utilization. This research focuses on the use of multi-scale image texture analysis techniques using Gabor filter banks and Wavelet transformations. Gabor filter banks model texture as irradiance patterns in an image over...
Ravikumar, Rahul
2009-05-15T23:59:59.000Z
to texture information extraction and utilization. This research focuses on the use of multi-scale image texture analysis techniques using Gabor filter banks and Wavelet transformations. Gabor filter banks model texture as irradiance patterns in an image over...
Multiscale Simulations of Materials: Exploring New Physics and Applications
Levitt and Arieh Warshel "for the development of multiscale models for complex chemical systems challenge of sustainable energy Report of Intergovernmental Panel on Climate Change 25% 30% Time and resources running out #12;#12;Sunlight hitting the dark discs could power the whole world: " solar cells
MULTISCALE NUMERICAL STUDY OF TURBULENT FLOW AND BUBBLE ENTRAINMENT
Kirby, James T.
MULTISCALE NUMERICAL STUDY OF TURBULENT FLOW AND BUBBLE ENTRAINMENT IN THE SURF ZONE BY GANGFENG MA . . . . . . . . . . . . . . . . . . . . . 3 1.1.2 Numerical Investigations . . . . . . . . . . . . . . . . . . . . . 5 1.2 Bubble Entrainment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.4 Bubble Entrainment Model . . . . . . . . . . . . . . . . . . . . . . . 18 2.5 Bubble Breakup
Multi-scale First-Principles Modeling of Three-Phase System of Polymer Electrolyte Membrane Fuel Cel
Brunello, Giuseppe; Choi, Ji; Harvey, David; Jang, Seung
2012-07-01T23:59:59.000Z
The three-phase system consisting of Nafion, graphite and platinum in the presence of water is studied using molecule dynamics simulation. The force fields describing the molecular interaction between the components in the system are developed to reproduce the energies calculated from density functional theory modeling. The configuration of such complicated three-phase system is predicted through MD simulations. The nanophase-segregation and transport properties are investigated from the equilibrium state. The coverage of the electrolyte on the platinum surface and the dissolution of oxygen are analyzed.
Zhang, Xuesong; Sahajpal, Ritvik; Manowitz, D.; Zhao, Kaiguang; LeDuc, Stephen D.; Xu, Min; Xiong, Wei; Zhang, Aiping; Izaurralde, Roberto C.; Thomson, Allison M.; West, Tristram O.; Post, W. M.
2014-05-01T23:59:59.000Z
The development of effective measures to stabilize atmospheric CO2 concentration and mitigate negative impacts of climate change requires accurate quantification of the spatial variation and magnitude of the terrestrial carbon (C) flux. However, the spatial pattern and strength of terrestrial C sinks and sources remain uncertain. In this study, we designed a spatially-explicit agroecosystem modeling system by integrating the Environmental Policy Integrated Climate (EPIC) model with multiple sources of geospatial and surveyed datasets (including crop type map, elevation, climate forcing, fertilizer application, tillage type and distribution, and crop planting and harvesting date), and applied it to examine the sensitivity of cropland C flux simulations to two widely used soil databases (i.e. State Soil Geographic-STATSGO of a scale of 1:250,000 and Soil Survey Geographic-SSURGO of a scale of 1:24,000) in Iowa, USA. To efficiently execute numerous EPIC runs resulting from the use of high resolution spatial data (56m), we developed a parallelized version of EPIC. Both STATSGO and SSURGO led to similar simulations of crop yields and Net Ecosystem Production (NEP) estimates at the State level. However, substantial differences were observed at the county and sub-county (grid) levels. In general, the fine resolution SSURGO data outperformed the coarse resolution STATSGO data for county-scale crop-yield simulation, and within STATSGO, the area-weighted approach provided more accurate results. Further analysis showed that spatial distribution and magnitude of simulated NEP were more sensitive to the resolution difference between SSURGO and STATSGO at the county or grid scale. For over 60% of the cropland areas in Iowa, the deviations between STATSGO- and SSURGO-derived NEP were larger than 1MgCha(-1)yr(-1), or about half of the average cropland NEP, highlighting the significant uncertainty in spatial distribution and magnitude of simulated C fluxes resulting from differences in soil data resolution.
Short Communication Concurrent correction method for modeling
Kirby, James T.
Short Communication Concurrent correction method for modeling morphological response to dredging the morphological impact of an offshore dredging pit using a process-based model, the hydrodynamic conditions, often with the initial bathymetry profile before dredging. This lack of equilibrium causes a fast profile adjustment
Multiscale Simulation of Blood Flow in Brain Arteries with an Aneurysm
Leopold Grinberg; Vitali Morozov; Dmitry A. Fedosov; Joseph Insley; Michael Papka; Kalyan Kumaran; George Karniadakis
2013-04-24T23:59:59.000Z
Multi-scale modeling of arterial blood flow can shed light on the interaction between events happening at micro- and meso-scales (i.e., adhesion of red blood cells to the arterial wall, clot formation) and at macro-scales (i.e., change in flow patterns due to the clot). Coupled numerical simulations of such multi-scale flow require state-of-the-art computers and algorithms, along with techniques for multi-scale visualizations. This animation presents results of studies used in the development of a multi-scale visualization methodology. First we use streamlines to show the path the flow is taking as it moves through the system, including the aneurysm. Next we investigate the process of thrombus (blood clot) formation, which may be responsible for the rupture of aneurysms, by concentrating on the platelet blood cells, observing as they aggregate on the wall of the aneurysm
Multipole Extraction: A novel, model independent method
E. Stiliaris; C. N. Papanicolas
2007-03-20T23:59:59.000Z
A novel method for extracting multipole amplitudes in the nucleon resonance region from electroproduction data is presented. The method is based on statistical concepts and it relies heavily on Monte Carlo and simulation techniques; it produces precise identification and determination of the contributing multipole amplitudes in the resonance region and for the first time a rigorous determination of the associated experimental uncertainty. The results are demonstrated to be independent of any model bias. The method is applied in the reanalysis of the $Q^{2}=0.127 GeV^2/c^2$ Bates and Mainz $N\\to \\Delta$ data.
Multiscale Assessment of Wildlife Sustainability in Switchgrass...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Multiscale Assessment of Wildlife Sustainability in Switchgrass Biofuel Feedstock Production Jun 29 2015 03:30 PM - 04:30 PM Chris Lituma, The University of Tennessee, Knoxville...
Multiscale characterization and analysis of shapes
Prasad, Lakshman (Los Alamos, NM); Rao, Ramana (Sunnyvale, CA)
2002-01-01T23:59:59.000Z
An adaptive multiscale method approximates shapes with continuous or uniformly and densely sampled contours, with the purpose of sparsely and nonuniformly discretizing the boundaries of shapes at any prescribed resolution, while at the same time retaining the salient shape features at that resolution. In another aspect, a fundamental geometric filtering scheme using the Constrained Delaunay Triangulation (CDT) of polygonized shapes creates an efficient parsing of shapes into components that have semantic significance dependent only on the shapes' structure and not on their representations per se. A shape skeletonization process generalizes to sparsely discretized shapes, with the additional benefit of prunability to filter out irrelevant and morphologically insignificant features. The skeletal representation of characters of varying thickness and the elimination of insignificant and noisy spurs and branches from the skeleton greatly increases the robustness, reliability and recognition rates of character recognition algorithms.
Clustering attributed graphs: models, measures and methods
Bothorel, Cecile; Magnani, Matteo; Micenkova, Barbora
2015-01-01T23:59:59.000Z
Clustering a graph, i.e., assigning its nodes to groups, is an important operation whose best known application is the discovery of communities in social networks. Graph clustering and community detection have traditionally focused on graphs without attributes, with the notable exception of edge weights. However, these models only provide a partial representation of real social systems, that are thus often described using node attributes, representing features of the actors, and edge attributes, representing different kinds of relationships among them. We refer to these models as attributed graphs. Consequently, existing graph clustering methods have been recently extended to deal with node and edge attributes. This article is a literature survey on this topic, organizing and presenting recent research results in a uniform way, characterizing the main existing clustering methods and highlighting their conceptual differences. We also cover the important topic of clustering evaluation and identify current open ...
Geoelectrical Measurement of Multi-Scale Mass Transfer Parameters
Day-Lewis, Frederick; Singha, Kamini; Haggerty, Roy; Johnson, Tim; Binley, Andrew; Lane, John
2014-01-16T23:59:59.000Z
Mass transfer affects contaminant transport and is thought to control the efficiency of aquifer remediation at a number of sites within the Department of Energy (DOE) complex. An improved understanding of mass transfer is critical to meeting the enormous scientific and engineering challenges currently facing DOE. Informed design of site remedies and long-term stewardship of radionuclide-contaminated sites will require new cost-effective laboratory and field techniques to measure the parameters controlling mass transfer spatially and across a range of scales. In this project, we sought to capitalize on the geophysical signatures of mass transfer. Previous numerical modeling and pilot-scale field experiments suggested that mass transfer produces a geoelectrical signature—a hysteretic relation between sampled (mobile-domain) fluid conductivity and bulk (mobile + immobile) conductivity—over a range of scales relevant to aquifer remediation. In this work, we investigated the geoelectrical signature of mass transfer during tracer transport in a series of controlled experiments to determine the operation of controlling parameters, and also investigated the use of complex-resistivity (CR) as a means of quantifying mass transfer parameters in situ without tracer experiments. In an add-on component to our grant, we additionally considered nuclear magnetic resonance (NMR) to help parse mobile from immobile porosities. Including the NMR component, our revised study objectives were to: 1. Develop and demonstrate geophysical approaches to measure mass-transfer parameters spatially and over a range of scales, including the combination of electrical resistivity monitoring, tracer tests, complex resistivity, nuclear magnetic resonance, and materials characterization; and 2. Provide mass-transfer estimates for improved understanding of contaminant fate and transport at DOE sites, such as uranium transport at the Hanford 300 Area. To achieve our objectives, we implemented a 3-part research plan involving (1) development of computer codes and techniques to estimate mass-transfer parameters from time-lapse electrical data; (2) bench-scale experiments on synthetic materials and materials from cores from the Hanford 300 Area; and (3) field demonstration experiments at the DOE’s Hanford 300 Area. In a synergistic add-on to our workplan, we analyzed data from field experiments performed at the DOE Naturita Site under a separate DOE SBR grant, on which PI Day-Lewis served as co-PI. Techniques developed for application to Hanford datasets also were applied to data from Naturita. 1. Introduction The Department of Energy (DOE) faces enormous scientific and engineering challenges associated with the remediation of legacy contamination at former nuclear weapons production facilities. Selection, design and optimization of appropriate site remedies (e.g., pump-and-treat, biostimulation, or monitored natural attenuation) requires reliable predictive models of radionuclide fate and transport; however, our current modeling capabilities are limited by an incomplete understanding of multi-scale mass transfer—its rates, scales, and the heterogeneity of controlling parameters. At many DOE sites, long “tailing” behavior, concentration rebound, and slower-than-expected cleanup are observed; these observations are all consistent with multi-scale mass transfer [Haggerty and Gorelick, 1995; Haggerty et al., 2000; 2004], which renders pump-and-treat remediation and biotransformation inefficient and slow [Haggerty and Gorelick, 1994; Harvey et al., 1994; Wilson, 1997]. Despite the importance of mass transfer, there are significant uncertainties associated with controlling parameters, and the prevalence of mass transfer remains a point of debate [e.g., Hill et al., 2006; Molz et al., 2006] for lack of experimental methods to verify and measure it in situ or independently of tracer breakthrough. There is a critical need for new field-experimental techniques to measure mass transfer in-situ and estimate multi-scale and spatially variable mass-transfer parame
Dinner, Aaron
2014-01-01T23:59:59.000Z
THE JOURNAL OF CHEMICAL PHYSICS 140, 184114 (2014) Using multiscale preconditioning to accelerate, "coarse- grained (CG)" model to accelerate calculations with an accu- rate and expensive "fine-grained (FG
Alternative methods of modeling wind generation using production cost models
Milligan, M.R. [National Renewable Energy Lab., Golden, CO (United States)] [National Renewable Energy Lab., Golden, CO (United States); Pang, C.K. [P Plus Corp., Cupertino, CA (United States)] [P Plus Corp., Cupertino, CA (United States)
1996-08-01T23:59:59.000Z
This paper examines the methods of incorporating wind generation in two production costing models: one is a load duration curve (LDC) based model and the other is a chronological-based model. These two models were used to evaluate the impacts of wind generation on two utility systems using actual collected wind data at two locations with high potential for wind generation. The results are sensitive to the selected wind data and the level of benefits of wind generation is sensitive to the load forecast. The total production cost over a year obtained by the chronological approach does not differ significantly from that of the LDC approach, though the chronological commitment of units is more realistic and more accurate. Chronological models provide the capability of answering important questions about wind resources which are difficult or impossible to address with LDC models.
Multitier Multiscale Sensing: a new paradigm for actuated sensing
2007-01-01T23:59:59.000Z
of dynamic environmental phenomena include solar lightSolar light radiation Two- tier multiscale architecture Environmental
Adaptive model training system and method
Bickford, Randall L; Palnitkar, Rahul M
2014-11-18T23:59:59.000Z
An adaptive model training system and method for filtering asset operating data values acquired from a monitored asset for selectively choosing asset operating data values that meet at least one predefined criterion of good data quality while rejecting asset operating data values that fail to meet at least the one predefined criterion of good data quality; and recalibrating a previously trained or calibrated model having a learned scope of normal operation of the asset by utilizing the asset operating data values that meet at least the one predefined criterion of good data quality for adjusting the learned scope of normal operation of the asset for defining a recalibrated model having the adjusted learned scope of normal operation of the asset.
Adaptive model training system and method
Bickford, Randall L; Palnitkar, Rahul M; Lee, Vo
2014-04-15T23:59:59.000Z
An adaptive model training system and method for filtering asset operating data values acquired from a monitored asset for selectively choosing asset operating data values that meet at least one predefined criterion of good data quality while rejecting asset operating data values that fail to meet at least the one predefined criterion of good data quality; and recalibrating a previously trained or calibrated model having a learned scope of normal operation of the asset by utilizing the asset operating data values that meet at least the one predefined criterion of good data quality for adjusting the learned scope of normal operation of the asset for defining a recalibrated model having the adjusted learned scope of normal operation of the asset.
Yang, Zhaoqing; Khangaonkar, Tarang
2010-11-19T23:59:59.000Z
Water circulation in Puget Sound, a large complex estuary system in the Pacific Northwest coastal ocean of the United States, is governed by multiple spatially and temporally varying forcings from tides, atmosphere (wind, heating/cooling, precipitation/evaporation, pressure), and river inflows. In addition, the hydrodynamic response is affected strongly by geomorphic features, such as fjord-like bathymetry and complex shoreline features, resulting in many distinguishing characteristics in its main and sub-basins. To better understand the details of circulation features in Puget Sound and to assist with proposed nearshore restoration actions for improving water quality and the ecological health of Puget Sound, a high-resolution (around 50 m in estuaries and tide flats) hydrodynamic model for the entire Puget Sound was needed. Here, a threedimensional circulation model of Puget Sound using an unstructured-grid finite volume coastal ocean model is presented. The model was constructed with sufficient resolution in the nearshore region to address the complex coastline, multi-tidal channels, and tide flats. Model open boundaries were extended to the entrance of the Strait of Juan de Fuca and the northern end of the Strait of Georgia to account for the influences of ocean water intrusion from the Strait of Juan de Fuca and the Fraser River plume from the Strait of Georgia, respectively. Comparisons of model results, observed data, and associated error statistics for tidal elevation, velocity, temperature, and salinity indicate that the model is capable of simulating the general circulation patterns on the scale of a large estuarine system as well as detailed hydrodynamics in the nearshore tide flats. Tidal characteristics, temperature/salinity stratification, mean circulation, and river plumes in estuaries with tide flats are discussed.
Multiscale dynamics of solar magnetic structures
Vadim M. Uritsky; Joseph M. Davila
2012-01-10T23:59:59.000Z
Multiscale topological complexity of solar magnetic field is among the primary factors controlling energy release in the corona, including associated processes in the photospheric and chromospheric boundaries. We present a new approach for analyzing multiscale behavior of the photospheric magnetic flux underlying this dynamics as depicted by a sequence of high-resolution solar magnetograms. The approach involves two basic processing steps: (1) identification of timing and location of magnetic flux origin and demise events (as defined by DeForest et al., 2007) by tracking spatiotemporal evolution of unipolar and bipolar photospheric regions, and (2) analysis of collective behavior of the detected magnetic events using a generalized version of Grassberger - Procaccia correlation integral algorithm. The scale-free nature of the developed algorithms makes it possible to characterize the dynamics of the photospheric network across a wide range of distances and relaxation times. Three types of photospheric conditions are considered to test the method: a quiet photosphere, a solar active region (NOAA 10365) in a quiescent non-flaring state, and the same active region during a period of M-class flares. The results obtained show (1) the presence of a topologically complex asymmetrically fragmented magnetic network in the quiet photosphere driven by meso- and supergranulation, (2) the formation of non-potential magnetic structures with complex polarity separation lines inside the active region, and (3) statistical signatures of canceling bipolar magnetic structures coinciding with flaring activity in the active region. Each of these effects can represent an unstable magnetic configuration acting as an energy source for coronal dissipation and heating.
Final Technical Report "Multiscale Simulation Algorithms for Biochemical Systems"
Petzold, Linda R.
2012-10-25T23:59:59.000Z
Biochemical systems are inherently multiscale and stochastic. In microscopic systems formed by living cells, the small numbers of reactant molecules can result in dynamical behavior that is discrete and stochastic rather than continuous and deterministic. An analysis tool that respects these dynamical characteristics is the stochastic simulation algorithm (SSA, Gillespie, 1976), a numerical simulation procedure that is essentially exact for chemical systems that are spatially homogeneous or well stirred. Despite recent improvements, as a procedure that simulates every reaction event, the SSA is necessarily inefficient for most realistic problems. There are two main reasons for this, both arising from the multiscale nature of the underlying problem: (1) stiffness, i.e. the presence of multiple timescales, the fastest of which are stable; and (2) the need to include in the simulation both species that are present in relatively small quantities and should be modeled by a discrete stochastic process, and species that are present in larger quantities and are more efficiently modeled by a deterministic differential equation (or at some scale in between). This project has focused on the development of fast and adaptive algorithms, and the fun- damental theory upon which they must be based, for the multiscale simulation of biochemical systems. Areas addressed by this project include: (1) Theoretical and practical foundations for ac- celerated discrete stochastic simulation (tau-leaping); (2) Dealing with stiffness (fast reactions) in an efficient and well-justified manner in discrete stochastic simulation; (3) Development of adaptive multiscale algorithms for spatially homogeneous discrete stochastic simulation; (4) Development of high-performance SSA algorithms.
Multiscale eddy simulation for moist atmospheric convection: Preliminary investigation
Stechmann, Samuel N., E-mail: stechmann@wisc.edu [Department of Mathematics, University of Wisconsin-Madison (United States); Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison (United States)
2014-08-15T23:59:59.000Z
A multiscale computational framework is designed for simulating atmospheric convection and clouds. In this multiscale framework, large eddy simulation (LES) is used to model the coarse scales of 100 m and larger, and a stochastic, one-dimensional turbulence (ODT) model is used to represent the fine scales of 100 m and smaller. Coupled and evolving together, these two components provide a multiscale eddy simulation (MES). Through its fine-scale turbulence and moist thermodynamics, MES allows coarse grid cells to be partially cloudy and to encompass cloudy–clear air mixing on scales down to 1 m; in contrast, in typical LES such fine-scale processes are not represented or are parameterized using bulk deterministic closures. To illustrate MES and investigate its multiscale dynamics, a shallow cumulus cloud field is simulated. The fine-scale variability is seen to take a plausible form, with partially cloudy grid cells prominent near cloud edges and cloud top. From earlier theoretical work, this mixing of cloudy and clear air is believed to have an important impact on buoyancy. However, contrary to expectations based on earlier theoretical studies, the mean statistics of the bulk cloud field are essentially the same in MES and LES; possible reasons for this are discussed, including possible limitations in the present formulation of MES. One difference between LES and MES is seen in the coarse-scale turbulent kinetic energy, which appears to grow slowly in time due to incoherent stochastic fluctuations in the buoyancy. This and other considerations suggest the need for some type of spatial and/or temporal filtering to attenuate undersampling of the stochastic fine-scale processes.
Formal Support for an Informal Business Modelling Method \\Lambda
Chen-Burger, Yun-Heh (Jessica)
Formal Support for an Informal Business Modelling Method \\Lambda YunHeh ChenBurger, David emails: jessicac@dai.ed.ac.uk, dr@dai.ed.ac.uk September 1, 1998 Abstract Business modelling methods modelling method: IBM's Business System Devel opment Method (BSDM). We describe the knowledge which we
CONVERGENCE OF A MULTISCALE FINITE ELEMENT METHOD ...
1999-04-17T23:59:59.000Z
Mar 3, 1999 ... In the above proof, ul is used as an intermediate step towards ...... Current address: Exxon Production Research Company, P. O. Box 2189, Houston, TX 77252 ... Department of Mathematics, Purdue University, West Lafayette, ...
Generalized finite element method for multiscale analysis
Zhang, Lin
2004-11-15T23:59:59.000Z
solutions ||uh||U and the overkill solutions ||uov||U. Analytical void functions of order pvoid = 1 were employed for the simple handbook solutions psiX;1/2j . ..................... 30 3.2 Relative errors eGFEMREL (deltah,p,phb; gamma) for Problems I...GFEMREL (deltah,p,phb; gamma) for Problem I(a)-I(d). The approx- imate solutions were computed by employing the handbook functions psiX;1/2j , but no analytical void functions were used in the numerical con- struction of these functions...
Bayes Linear Uncertainty Analysis for Oil Reservoirs Based on Multiscale Computer Experiments
Oakley, Jeremy
of the input parameters for a reservoir model. Therefore, an uncertainty analysis for the model often proceedsBayes Linear Uncertainty Analysis for Oil Reservoirs Based on Multiscale Computer Experiments for the efficient management of the reservoir. In a Bayesian analysis, all of our uncertainties are incorporated
CBE EnergyPlus Modeling Methods for UFAD Systems
Webster, Tom; Bauman, Fred; Lee, Kwang Ho; Schiavon, Stefano; Daly, Alan; Hoyt, Tyler
2012-01-01T23:59:59.000Z
uc/item/4mt314vs CBE EnergyPlus Modeling Methods for UFADreport December 2012 CBE EnergyPlus Modeling Methods formodule specifications for EnergyPlus v3.1 and higher. We
Multiscale Problems: Numerical Analysis and Scientific Computing
Wirosoetisno, Djoko
/Transport Equations Alternative (Wind, Solar, Wave, . . . ) Weather and Climate Prediction Wave Energy Fuel CellsMultiscale Problems: Numerical Analysis and Scientific Computing with Applications in Energy inverse problems, data assimilation, stochastic differential equations Networks, compressed sensing
Multiscale ab initio approaches to materials physics
Engeness, Torkel Dyrbaek, 1972-
2003-01-01T23:59:59.000Z
This work presents new ab initio approaches to materials physics. We first introduce the multiscale approach to determination of thermal properties and changes in free energy. With this approach one can perform thermal ...
Property Variability Stochastic Multiscale Analysis and Design
Zabaras, Nicholas J.
Property Variability Stochastic Multiscale Analysis and Design of Engine Disks N. Zabaras, B. Wen, 7/28/2010 Materials Process Design and Control Laboratory Cornell University #12;Property Property Variability Due to Microscale Uncertainties Stochastic Forging Design Stochastic Forging Design
A multivariate quadrature based moment method for supersonic combustion modeling
Raman, Venkat
A multivariate quadrature based moment method for supersonic combustion modeling Pratik Donde- ture method of moments (DQMOM) is well suited for multivariate problems like combustion. Numerical is developed. A decoupling procedure allows extension of this method to multivariate problems. Se
Vikas Tomer; John Renaud
2010-08-31T23:59:59.000Z
It is estimated that by using better and improved high temperature structural materials, the power generation efficiency of the power plants can be increased by 15% resulting in significant cost savings. One such promising material system for future high-temperature structural applications in power plants is Silicon Carbide-Silicon Nitride (SiC-Si{sub 3}N{sub 4}) nanoceramic matrix composites. The described research work focuses on multiscale simulation-based design of these SiC-Si{sub 3}N{sub 4} nanoceramic matrix composites. There were two primary objectives of the research: (1) Development of a multiscale simulation tool and corresponding multiscale analyses of the high-temperature creep and fracture resistance properties of the SiC-Si{sub 3}N{sub 4} nanocomposites at nano-, meso- and continuum length- and timescales; and (2) Development of a simulation-based robust design optimization methodology for application to the multiscale simulations to predict the range of the most suitable phase morphologies for the desired high-temperature properties of the SiC-Si{sub 3}N{sub 4} nanocomposites. The multiscale simulation tool is based on a combination of molecular dynamics (MD), cohesive finite element method (CFEM), and continuum level modeling for characterizing time-dependent material deformation behavior. The material simulation tool is incorporated in a variable fidelity model management based design optimization framework. Material modeling includes development of an experimental verification framework. Using material models based on multiscaling, it was found using molecular simulations that clustering of the SiC particles near Si{sub 3}N{sub 4} grain boundaries leads to significant nanocomposite strengthening and significant rise in fracture resistance. It was found that a control of grain boundary thicknesses by dispersing non-stoichiometric carbide or nitride phases can lead to reduction in strength however significant rise in fracture strength. The temperature dependent strength and microstructural stability was also significantly depended upon the dispersion of new phases at grain boundaries. The material design framework incorporates high temperature creep and mechanical strength data in order to develop a collaborative multiscale framework of morphology optimization. The work also incorporates a computer aided material design dataset development procedure where a systematic dataset on material properties and morphology correlation could be obtained depending upon a material processing scientist's requirements. Two different aspects covered under this requirement are: (1) performing morphology related analyses at the nanoscale and at the microscale to develop a multiscale material design and analyses capability; (2) linking material behavior analyses with the developed design tool to form a set of material design problems that illustrate the range of material design dataset development that could be performed. Overall, a software based methodology to design microstructure of particle based ceramic nanocomposites has been developed. This methodology has been shown to predict changes in phase morphologies required for achieving optimal balance of conflicting properties such as minimal creep strain rate and high fracture strength at high temperatures. The methodology incorporates complex material models including atomistic approaches. The methodology will be useful to design materials for high temperature applications including those of interest to DoE while significantly reducing cost of expensive experiments.
Graham, Samuel Jr. (; .); Wong, C. C.; Piekos, Edward Stanley
2004-02-01T23:59:59.000Z
A concurrent computational and experimental investigation of thermal transport is performed with the goal of improving understanding of, and predictive capability for, thermal transport in microdevices. The computational component involves Monte Carlo simulation of phonon transport. In these simulations, all acoustic modes are included and their properties are drawn from a realistic dispersion relation. Phonon-phonon and phonon-boundary scattering events are treated independently. A new set of phonon-phonon scattering coefficients are proposed that reflect the elimination of assumptions present in earlier analytical work from the simulation. The experimental component involves steady-state measurement of thermal conductivity on silicon films as thin as 340nm at a range of temperatures. Agreement between the experiment and simulation on single-crystal silicon thin films is excellent, Agreement for polycrystalline films is promising, but significant work remains to be done before predictions can be made confidently. Knowledge gained from these efforts was used to construct improved semiclassical models with the goal of representing microscale effects in existing macroscale codes in a computationally efficient manner.
that have been used to quantify the effect of clouds on radiation budget in both modeling and observationalSURFACE CLOUD RADIATIVE FORCING, CLOUD FRACTION AND CLOUD ALBEDO: THEIR RELATIONSHIP AND MULTISCALE/Atmospheric Sciences Division Brookhaven National Laboratory P.O. Box, Upton, NY www.bnl.gov ABSTRACT Cloud-radiation
Kulkarni, Yashashree
2012-01-01T23:59:59.000Z
Journal for Multiscale Computational Engineering, 10 (1): 1331 (2012) COARSE GRAINING OF ATOMISTIC Engineering, University of Houston, Houston, TX 77204, E-mail: ykulkarni@uh.edu In this paper, we propose- scription. These models are usually broadly classified as sequential or concurrent approaches. Sequential
An Expectation-Maximization Method for Calibrating Synchronous Machine Models
Meng, Da; Zhou, Ning; Lu, Shuai; Lin, Guang
2013-07-21T23:59:59.000Z
The accuracy of a power system dynamic model is essential to its secure and efficient operation. Lower confidence in model accuracy usually leads to conservative operation and lowers asset usage. To improve model accuracy, this paper proposes an expectation-maximization (EM) method to calibrate the synchronous machine model using phasor measurement unit (PMU) data. First, an extended Kalman filter (EKF) is applied to estimate the dynamic states using measurement data. Then, the parameters are calculated based on the estimated states using maximum likelihood estimation (MLE) method. The EM method iterates over the preceding two steps to improve estimation accuracy. The proposed EM method’s performance is evaluated using a single-machine infinite bus system and compared with a method where both state and parameters are estimated using an EKF method. Sensitivity studies of the parameter calibration using EM method are also presented to show the robustness of the proposed method for different levels of measurement noise and initial parameter uncertainty.
A multiscale Molecular Dynamics approach to Contact Mechanics
C. Yang; U. Tartaglino; B. N. J. Persson
2006-01-05T23:59:59.000Z
The friction and adhesion between elastic bodies are strongly influenced by the roughness of the surfaces in contact. Here we develop a multiscale molecular dynamics approach to contact mechanics, which can be used also when the surfaces have roughness on many different length-scales, e.g., for self affine fractal surfaces. As an illustration we consider the contact between randomly rough surfaces, and show that the contact area varies linearly with the load for small load. We also analyze the contact morphology and the pressure distribution at different magnification, both with and without adhesion. The calculations are compared with analytical contact mechanics models based on continuum mechanics.
Interior Point Methods, Nonlinear Models & Parallelisation
Grothey, Andreas
;Overview Asset and Liability Management Models Mean-Variance Formulation/Stochastic Programming Structure Grothey IPM, Nonlinear Models & Parallelisation #12;Portfolio Optimization: Asset and Liability Management and Liability Management A set of assets J = {1, ..., J} is given (e.g. bonds, stock, real estate). At every
Modeling Pronunciation Variation for a Dutch CSR: Testing Three Methods
Wester, Mirjam; Kessens, Judith M; Strik, Helmer
This paper describes how the performance of a continuous speech recognizer for Dutch has been improved by modeling pronunciation variation. We used three methods to model pronunciation variation. First, within-word variation ...
Simplified methods of modeling multilayer reservoirs
Ryou, Sangsoo
1993-01-01T23:59:59.000Z
and Camacho suggested for hydraulically fracture wells. We also examined modeling responses of wells with positive skin factors completed in multilayer reservoirs with equivalent single layer solutions. More specifically, this work examined the boundary...
Lee, Hee Eun
2004-09-30T23:59:59.000Z
wing with the Synthetic Jet Actuator (SJA). We use the Regularized Orthogonal Least Square method (Mark, 1996) and the RAN-EKF (Resource Allocating Network-Extended Kalman Filter) as a reference approach. The first part of the algorithm determines...
Tuning Methods for Model Predictive Controllers
methods for tuning of a Gas-Oil Furnace, a Wood-Berry Distillation Column and a Cement Mill Circuit. #12 to develop a tuning toolbox for SISO systems, which visualizes the performance of control designs. A study systemer, som kan visualisere ydelsen af regulator designs. Der er undersřgt, hvorledes ydelsesm
Minisymposium on Validated Methods: Applications to Modeling, Analysis,
Kreinovich, Vladik
in Medicine and Engineering Organizers: Andreas Rauh1 and Ekaterina Auer2 During the last decades, computer of the mathematical model of the considered process. In this minisymposium, we focus on validated methods as a meansMinisymposium on Validated Methods: Applications to Modeling, Analysis, and Design of Systems
Zhigilei, Leonid V.
of Laser Ablation: Applications to Nanotechnology Leonid V. Zhigilei1 and Avinash M. Dongare 1 Abstract-driven methods in nanotechnology. In this pa- per we discuss two computational schemes developed for simulation, applications of laser ablation have been extended into emerging area of nanotechnology. In particular, laser
Hydrostatic Hamiltonian particle-mesh (HPM) methods for atmospheric modeling.
Reich, Sebastian
Hydrostatic Hamiltonian particle-mesh (HPM) methods for atmospheric modeling. Seoleun Shin Sebastian Reich Jason Frank August 19, 2011 Abstract We develop a hydrostatic Hamiltonian particle-mesh (HPM) method for efficient long-term numerical integration of the atmosphere. In the HPM method, the hydro
Hydrostatic Hamiltonian particle mesh (HPM) methods for atmospheric modeling.
Frank, Jason
Hydrostatic Hamiltonian particle mesh (HPM) methods for atmospheric modeling. Seoleun Shin Sebastian Reich Jason Frank March 17, 2011 Abstract We develop a hydrostatic Hamiltonian particle mesh (HPM) method for efficient long-term numerical integration of the atmosphere. In the HPM method, the hydro
MULTILEVEL FAST MULTIPOLE METHOD FOR MODELING PERMEABLE STRUCTURES
Sarabandi, Kamal
MULTILEVEL FAST MULTIPOLE METHOD FOR MODELING PERMEABLE STRUCTURES USING CONFORMAL FINITE ELEMENTS #12;Copyright c Kubilay Sertel All Rights Reserved 2003 #12;ABSTRACT MULTILEVEL FAST MULTIPOLE METHOD fast multipole method for impen- etrable targets in the context of flat-triangular geometry
A General Method for Feature Matching and Model Extraction
Olson, Clark F.
A General Method for Feature Matching and Model Extraction Clark F. Olson Jet Propulsion Laboratory is extracted from or #12;t to data that draws bene#12;ts from both generate-and-test methods and those based that are ecient and robust. We apply this method to object recognition, geometric primitive extraction, robust
Cobb, Barry R.; Shenoy, Prakash P.
2006-04-01T23:59:59.000Z
In this paper, we propose the plausibility transformation method for translating Dempster-Shafer (D-S) belief function models to probability models, and describe some of its properties. There are many other transformation methods used...
Paris-Sud XI, Université de
Hydraulic transmissivity and heat exchanges: aperture lowpass filtering model 1 SUMMARY Natural aperture that describes at best the macroscopic properties (hydraulic conductivity, heat exchange of the effective hydraulic and thermal properties (apertures). A detailed study of the influence of the bandwidth
Ghosh, Somnath
2006-01-01T23:59:59.000Z
based pre-processor for multi-scale modelling of cast aluminium alloys Somnath Ghosh1,3 , D M Valiveti4 aluminium alloy with different secondary dendrite arm spacings SDAS is demonstrated. The MDP method in the UK 1363 #12;1364 S Ghosh et al 1. Introduction Cast aluminium alloys such as the 319-type
Liu, Dajiang [Ames Laboratory; Evans, James W. [Ames Laboratory
2013-12-01T23:59:59.000Z
A realistic molecular-level description of catalytic reactions on single-crystal metal surfaces can be provided by stochastic multisite lattice-gas (msLG) models. This approach has general applicability, although in this report, we will focus on the example of CO-oxidation on the unreconstructed fcc metal (100) or M(100) surfaces of common catalyst metals M = Pd, Rh, Pt and Ir (i.e., avoiding regimes where Pt and Ir reconstruct). These models can capture the thermodynamics and kinetics of adsorbed layers for the individual reactants species, such as CO/M(100) and O/M(100), as well as the interaction and reaction between different reactant species in mixed adlayers, such as (CO + O)/M(100). The msLG models allow population of any of hollow, bridge, and top sites. This enables a more flexible and realistic description of adsorption and adlayer ordering, as well as of reaction configurations and configuration-dependent barriers. Adspecies adsorption and interaction energies, as well as barriers for various processes, constitute key model input. The choice of these energies is guided by experimental observations, as well as by extensive Density Functional Theory analysis. Model behavior is assessed via Kinetic Monte Carlo (KMC) simulation. We also address the simulation challenges and theoretical ramifications associated with very rapid diffusion and local equilibration of reactant adspecies such as CO. These msLG models are applied to describe adsorption, ordering, and temperature programmed desorption (TPD) for individual CO/M(100) and O/M(100) reactant adlayers. In addition, they are also applied to predict mixed (CO + O)/M(100) adlayer structure on the nanoscale, the complete bifurcation diagram for reactive steady-states under continuous flow conditions, temperature programmed reaction (TPR) spectra, and titration reactions for the CO-oxidation reaction. Extensive and reasonably successful comparison of model predictions is made with experimental data. Furthermore, we discuss the possible transition from traditional mean-field-type bistability and reaction kinetics for lower-pressure to multistability and enhanced fluctuation effects for moderate- or higher-pressure. Behavior in the latter regime reflects a stronger influence of adspecies interactions and also lower diffusivity in the higher-coverage mixed adlayer. We also analyze mesoscale spatiotemporal behavior including the propagation of reaction diffusion fronts between bistable reactive and inactive states, and associated nucleation-mediated transitions between these states. This behavior is controlled by complex surface mass transport processes, specifically chemical diffusion in mixed reactant adlayers for which we provide a precise theoretical formulation. The msLG models together with an appropriate treatment of chemical diffusivity enable equation-free heterogeneous coupled lattice-gas (HCLG) simulations of spatiotemporal behavior. In addition, msLG + HCLG modeling can describe coverage variations across polycrystalline catalysts surfaces, pressure variations across catalyst surfaces in microreactors, and could be incorporated into a multiphysics framework to describe mass and heat transfer limitations for high-pressure catalysis. (C) 2013 Elsevier Ltd. All rights reserved.
Systems and methods for modeling and analyzing networks
Hill, Colin C; Church, Bruce W; McDonagh, Paul D; Khalil, Iya G; Neyarapally, Thomas A; Pitluk, Zachary W
2013-10-29T23:59:59.000Z
The systems and methods described herein utilize a probabilistic modeling framework for reverse engineering an ensemble of causal models, from data and then forward simulating the ensemble of models to analyze and predict the behavior of the network. In certain embodiments, the systems and methods described herein include data-driven techniques for developing causal models for biological networks. Causal network models include computational representations of the causal relationships between independent variables such as a compound of interest and dependent variables such as measured DNA alterations, changes in mRNA, protein, and metabolites to phenotypic readouts of efficacy and toxicity.
A decision-theoretic method for surrogate model selection.
Field, Richard V., Jr. (.,; .)
2005-06-01T23:59:59.000Z
The use of surrogate models to approximate computationally expensive simulation models, e.g., large comprehensive finite element models, is widespread. Applications include surrogate models for design, sensitivity analysis, and/or uncertainty quantification. Typically, a surrogate model is defined by a postulated functional form; values for the surrogate model parameters are estimated using results from a limited number of solutions to the comprehensive model. In general, there may be multiple surrogate models, each defined by possibly a different functional form, consistent with the limited data from the comprehensive model. We refer to each as a candidate surrogate model. Methods are developed and applied to select the optimal surrogate model from the collection of candidate surrogate models. The classical approach is to select the surrogate model that best fits the data provided by the comprehensive model; this technique is independent of the model use and, therefore, may be inappropriate for some applications. The proposed approach applies techniques from decision theory, where postulated utility functions are used to quantify the model use. Two applications are presented to illustrate the methods. These include surrogate model selection for the purpose of: (1) estimating the minimum of a deterministic function, and (2) the design under uncertainty of a physical system.
Process Model Discovery: A Method Based on Transition System Decomposition
van der Aalst, Wil
Process Model Discovery: A Method Based on Transition System Decomposition Anna A. Kalenkova1 discovery algo- rithms deal with large data sets to learn automatically process models. As more event data by the unified process model. The proposed discovery algorithm is illustrated using a running example. 1
Advanced methods of flux identification for clarifierthickener simulation models q
Bürger, Raimund
with mathematical models for the batch and continuous sedimentation of finely divided solid par- ticles dispersed: Solidliquid separation Thickener simulation Batch sedimentation Flux identification Mathematical modelAdvanced methods of flux identification for clarifierthickener simulation models q Fernando
Empirical Multiscale Networks of Cellular Regulation
de Bivort, Benjamin
Empirical Multiscale Networks of Cellular Regulation Benjamin de Bivort1* , Sui Huang2,3,4 , Yaneer Bar-Yam5 1 Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, Boston, Massachusetts, United States of America, 3 Department of Pathology, Children's Hospital
Multiscale simulation of blood flow in brain arteries with an aneurysm
Grinberg, Leopold; Fedosov, Dmitry A; Insley, Joseph A; Papka, Michael E; Kumaran, Kalyan; Karniadakis, George Em
2011-01-01T23:59:59.000Z
Interfacing atomistic-based with continuum-based simulation codes is now required in many multiscale physical and biological systems. We present the first results from coupled atomistic-continuum simulations on 190,000 processors. Platelet aggregation in the patient-specific model of an aneurysm has been modeled using a high-order spectral/hp element Navier-Stokes solver with a stochastic (coarse-grained) Molecular Dynamics solver based on Dissipative Particle Dynamics (DPD).
Formal Support for an Informal Business Modelling Method
Chen-Burger, Jessica; Robertson, Dave; Stader, Justine
2000-01-01T23:59:59.000Z
Business modelling methods are popular but, since they operate primarily in the early stages of software lifecycles, most are informal. This paper describes how we have used a conventional formal notation (first order predicate logic) in combination...
CBE EnergyPlus modeling methods for UFAD systems
Webster, T.; Bauman, F.; Lee, K.; Schiavon, S.; Daly, A.; Hoyt, T.
2013-01-01T23:59:59.000Z
Summary Report CBE EnergyPlus Modeling Methods for UFADmodule specifications for EnergyPlus v3.1 and higher. Wethe term Kc used in the Energyplus documentation. It is the
Constraining climate model properties using optimal fingerprint detection methods
Forest, Chris Eliot.; Allen, Myles R.; Sokolov, Andrei P.; Stone, Peter H.
We present a method for constraining key properties of the climate system that are important for climate prediction (climate sensitivity and rate of heat penetration into the deep ocean) by comparing a model's response to ...
Multiscale Simulations of Li Ion Conductivity in Solid Electrolyte
Sushko, Maria L.; Rosso, Kevin M.; Zhang, Jiguang; Liu, Jun
2011-09-15T23:59:59.000Z
Optimizing solid electrolyte design for its application in Li-ion and Li-metal batteries requires a fundamental understanding of the mechanism of ion and electron transport in the material at the nano- to micron-scales. We have performed simulations of Li+ and electron conductivity in lithium phosphorus oxynitride, one of the most widely used solid electrolytes, using novel hierarchical multiscale models. By comparing the results of one- and three-dimensional models we show that for this material with complex non-linear Li+ diffusion pathways three-dimensional description is essential for reproducing experimentally measured conductivity. We also suggest some basic principles to design optimum electrolyte tailored for low and high temperature regimes.
Physics-based multiscale coupling for full core nuclear reactor...
Office of Scientific and Technical Information (OSTI)
multiscale coupling for full core nuclear reactor simulation Numerical simulation of nuclear reactors is a key technology in the quest for improvements in efficiency, safety,...
Automatic Lung Vessel Segmentation via Stacked Multiscale Feature Learning
Toronto, University of
Automatic Lung Vessel Segmentation via Stacked Multiscale Feature Learning Ryan Kiros, Karteek We introduce a representation learning approach to segmenting vessels in the lungs. Our algorithm
CHANGE PROCESS MODELLING USING THE EKD-CHANGE MANAGEMENT METHOD
Boyer, Edmond
CHANGE PROCESS MODELLING USING THE EKD-CHANGE MANAGEMENT METHOD S. Nurcan* , J. Barrios*1 , G The Enterprise Knowledge Development - Change Management Method (EKD-CMM) provides a systematic way to organise and to guide the organisational change management. The EKD-CMM road map, implemented in the electronic guide
Byrne, Jason P.; Morgan, Huw; Habbal, Shadia R. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Gallagher, Peter T., E-mail: jbyrne@ifa.hawaii.edu [Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2 (Ireland)
2012-06-20T23:59:59.000Z
Studying coronal mass ejections (CMEs) in coronagraph data can be challenging due to their diffuse structure and transient nature, and user-specific biases may be introduced through visual inspection of the images. The large amount of data available from the Solar and Heliospheric Observatory (SOHO), Solar TErrestrial RElations Observatory (STEREO), and future coronagraph missions also makes manual cataloging of CMEs tedious, and so a robust method of detection and analysis is required. This has led to the development of automated CME detection and cataloging packages such as CACTus, SEEDS, and ARTEMIS. Here, we present the development of a new CORIMP (coronal image processing) CME detection and tracking technique that overcomes many of the drawbacks of current catalogs. It works by first employing the dynamic CME separation technique outlined in a companion paper, and then characterizing CME structure via a multiscale edge-detection algorithm. The detections are chained through time to determine the CME kinematics and morphological changes as it propagates across the plane of sky. The effectiveness of the method is demonstrated by its application to a selection of SOHO/LASCO and STEREO/SECCHI images, as well as to synthetic coronagraph images created from a model corona with a variety of CMEs. The algorithms described in this article are being applied to the whole LASCO and SECCHI data sets, and a catalog of results will soon be available to the public.
Matrix Modeling Methods for Spaceflight Campaign Logistics Analysis
de Weck, Olivier L.
Matrix Modeling Methods for Spaceflight Campaign Logistics Analysis Afreen Siddiqi and Olivier L-based modeling approach for analyzing spaceflight campaign logistics. A campaign is considered to be a series logistics properties. A logistics strategy index is proposed for quantifying manifesting strategies
A Primer on Hardware Security: Models, Methods, and Metrics
INVITED P A P E R A Primer on Hardware Security: Models, Methods, and Metrics The paper is a primer on hardware security threat models, metrics, and remedies. By Masoud Rostami, Farinaz Koushanfar, and Ramesh) production supply chain has intro- duced hardware-based vulnerabilities. Existing literature in hardware
Topic Models: A Novel Method for Modeling Couple and Family David C. Atkins
Rubin, Tim
Topic Models: A Novel Method for Modeling Couple and Family Text Data David C. Atkins University participants' responses are not forced into a set number of categories, text-based data can be very rich an alternative method for analyzing text data called topic models (Steyvers & Griffiths, 2006), which has not yet
High-order / low-order methods for ocean modeling
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Newman, Christopher; Womeldorff, Geoff; Chacón, Luis; Knoll, Dana A.
2015-01-01T23:59:59.000Z
We examine a High Order/Low Order (HOLO) approach for a z-level ocean model and show that the traditional semi-implicit and split-explicit methods, as well as a recent preconditioning strategy, can easily be cast in the framework of HOLO methods. The HOLO formulation admits an implicit-explicit method that is algorithmically scalable and second-order accurate, allowing timesteps much larger than the barotropic time scale. We show how HOLO approaches, in particular the implicit-explicit method, can provide a solid route for ocean simulation to heterogeneous computing and exascale environments.
Multiscale stochastic simulations of chemical reactions with regulated scale separation
Koumoutsakos, Petros, E-mail: petros@ethz.ch [Chair of Computational Science, Clausiusstrasse 33, ETH Zurich, CH-8092 (Switzerland)] [Chair of Computational Science, Clausiusstrasse 33, ETH Zurich, CH-8092 (Switzerland); Feigelman, Justin [Chair of Computational Science, Clausiusstrasse 33, ETH Zurich, CH-8092 (Switzerland)] [Chair of Computational Science, Clausiusstrasse 33, ETH Zurich, CH-8092 (Switzerland)
2013-07-01T23:59:59.000Z
We present a coupling of multiscale frameworks with accelerated stochastic simulation algorithms for systems of chemical reactions with disparate propensities. The algorithms regulate the propensities of the fast and slow reactions of the system, using alternating micro and macro sub-steps simulated with accelerated algorithms such as ? and R-leaping. The proposed algorithms are shown to provide significant speedups in simulations of stiff systems of chemical reactions with a trade-off in accuracy as controlled by a regulating parameter. More importantly, the error of the methods exhibits a cutoff phenomenon that allows for optimal parameter choices. Numerical experiments demonstrate that hybrid algorithms involving accelerated stochastic simulations can be, in certain cases, more accurate while faster, than their corresponding stochastic simulation algorithm counterparts.
Multiscale Modeling and Homogenization of Composite Materials
Mseis, George
2010-01-01T23:59:59.000Z
of superelasticity in nitinol polycrystals. Computationalto superelasticity of Nitinol polycrystals and in Nadler and
Representing and modeling images with multiscale local
Simoncelli, Eero
few years has been a very good experience. I would like to thank some friends I was fortunate to get, Barney Bramham, Tyler Neylon, Fred Lalibert´e. I would like to thank my friends and colleagues from the Laboratory for Computational Vision : Umesh Rajashekar, Alan Stocker, Zhou Wang, Cynthia Rudin, Rosa Figueras
MultiscaleModeling andComputation
E, Weinan
example with multiple time scales is that of protein folding. While the time scale for the vibration for protein folding, then the electronic structures of the water Weinan E is professor of mathematics
A SECRET KEY BASED MULTISCALE FRAGILE WATERMARK IN THE WAVELET Hua Yuan and Xiao-Ping Zhang
Zhang, Xiao-Ping
A SECRET KEY BASED MULTISCALE FRAGILE WATERMARK IN THE WAVELET DOMAIN Hua Yuan and Xiao-Ping Zhang. In this paper, a secret key based fragile watermarking scheme is presented based on this statistical model and modified in a way to form special relationships for image authentication. The secret key is designed
Localized Scale Coupling and New Educational Paradigms in Multiscale Mathematics and Science
LEAL, L. GARY
2013-06-30T23:59:59.000Z
One of the most challenging multi-scale simulation problems in the area of multi-phase materials is to develop effective computational techniques for the prediction of coalescence and related phenomena involving rupture of a thin liquid film due to the onset of instability driven by van der Waals or other micro-scale attractive forces. Accurate modeling of this process is critical to prediction of the outcome of milling processes for immiscible polymer blends, one of the most important routes to new advanced polymeric materials. In typical situations, the blend evolves into an ?emulsion? of dispersed phase drops in a continuous matrix fluid. Coalescence is then a critical factor in determining the size distribution of the dispersed phase, but is extremely difficult to predict from first principles. The thin film separating two drops may only achieve rupture at dimensions of approximately 10 nm while the drop sizes are 0(10 ?m). It is essential to achieve very accurate solutions for the flow and for the interface shape at both the macroscale of the full drops, and within the thin film (where the destabilizing disjoining pressure due to van der Waals forces is proportional approximately to the inverse third power of the local film thickness, h-3). Furthermore, the fluids of interest are polymeric (through Newtonian) and the classical continuum description begins to fail as the film thins ? requiring incorporation of molecular effects, such as a hybrid code that incorporates a version of coarse grain molecular dynamics within the thin film coupled with a classical continuum description elsewhere in the flow domain. Finally, the presence of surface active additions, either surfactants (in the form of di-block copolymers) or surface-functionalized micro- or nano-scale particles, adds an additional level of complexity, requiring development of a distinct numerical method to predict the nonuniform concentration gradients of these additives that are responsible for Marangoni stresses at the interface. Again, the physical dimensions of these additives may become comparable to the thin film dimensions, requiring an additional layer of multi-scale modeling.
Multiscale Computation. Needs and Opportunities for BER Science
Scheibe, Timothy D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smith, Jeremy C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2015-01-01T23:59:59.000Z
The Environmental Molecular Sciences Laboratory (EMSL), a scientific user facility managed by Pacific Northwest National Laboratory for the U.S. Department of Energy, Office of Biological and Environmental Research (BER), conducted a one-day workshop on August 26, 2014 on the topic of “Multiscale Computation: Needs and Opportunities for BER Science.” Twenty invited participants, from various computational disciplines within the BER program research areas, were charged with the following objectives; Identify BER-relevant models and their potential cross-scale linkages that could be exploited to better connect molecular-scale research to BER research at larger scales and; Identify critical science directions that will motivate EMSL decisions regarding future computational (hardware and software) architectures.
Dynamics of a neural system with a multiscale architecture
Breakspear, Michael
Dynamics of a neural system with a multiscale architecture Michael Breakspear1,2,3,* and Cornelis J of Clinical Neurophysiology, VU University Medical Centre, Amsterdam, The Netherlands The architecture for neural systems in which the dynamics are nested within a multiscale architecture. In essence
Faculty Position in Multi-scale Manufacturing Technologies
Psaltis, Demetri
-precision additive manufacturing technologies; · multi-scale micro-precision manufacturing; · high throughput. Christian Enz Search Committee Chair E-mail: manufacturing-search@epfl.ch For additional information on EPFLFaculty Position in Multi-scale Manufacturing Technologies at the Ecole polytechnique fédérale de
ANDREA BRAIDES Multi-scale Problems for Lattice Systems
Braides, Andrea
ANDREA BRAIDES Multi-scale Problems for Lattice Systems Multi-scale Problems in Sustainable Resource Management The Royal Netherlands Academy of Arts and Sciences September 9, 2010 A.Braides: Multi. -convergence for Beginners, OUP 2002 B. Handbook of -convergence (Handbook of Diff. Eqns, Elsevier, 2006) A
Critical Zones in Desert Fog: Aids to Multiscale Navigation
Furnas, George W.
Critical Zones in Desert Fog: Aids to Multiscale Navigation Susanne Jul Computer Science +1 734-763-0076 furnas@umich.edu ABSTRACT In this paper, we introduce the problem of "desert fog desert fog in multiscale electronic worlds. Prototypes of these aids have been implemented
Curve fitting methods for solar radiation data modeling
Karim, Samsul Ariffin Abdul, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my; Singh, Balbir Singh Mahinder, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my [Department of Fundamental and Applied Sciences, Faculty of Sciences and Information Technology, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan (Malaysia)
2014-10-24T23:59:59.000Z
This paper studies the use of several type of curve fitting method to smooth the global solar radiation data. After the data have been fitted by using curve fitting method, the mathematical model of global solar radiation will be developed. The error measurement was calculated by using goodness-fit statistics such as root mean square error (RMSE) and the value of R{sup 2}. The best fitting methods will be used as a starting point for the construction of mathematical modeling of solar radiation received in Universiti Teknologi PETRONAS (UTP) Malaysia. Numerical results indicated that Gaussian fitting and sine fitting (both with two terms) gives better results as compare with the other fitting methods.
A meshless method for modeling convective heat transfer
Carrington, David B [Los Alamos National Laboratory
2010-01-01T23:59:59.000Z
A meshless method is used in a projection-based approach to solve the primitive equations for fluid flow with heat transfer. The method is easy to implement in a MATLAB format. Radial basis functions are used to solve two benchmark test cases: natural convection in a square enclosure and flow with forced convection over a backward facing step. The results are compared with two popular and widely used commercial codes: COMSOL, a finite element model, and FLUENT, a finite volume-based model.
Multilevel method for modeling large-scale networks.
Safro, I. M. (Mathematics and Computer Science)
2012-02-24T23:59:59.000Z
Understanding the behavior of real complex networks is of great theoretical and practical significance. It includes developing accurate artificial models whose topological properties are similar to the real networks, generating the artificial networks at different scales under special conditions, investigating a network dynamics, reconstructing missing data, predicting network response, detecting anomalies and other tasks. Network generation, reconstruction, and prediction of its future topology are central issues of this field. In this project, we address the questions related to the understanding of the network modeling, investigating its structure and properties, and generating artificial networks. Most of the modern network generation methods are based either on various random graph models (reinforced by a set of properties such as power law distribution of node degrees, graph diameter, and number of triangles) or on the principle of replicating an existing model with elements of randomization such as R-MAT generator and Kronecker product modeling. Hierarchical models operate at different levels of network hierarchy but with the same finest elements of the network. However, in many cases the methods that include randomization and replication elements on the finest relationships between network nodes and modeling that addresses the problem of preserving a set of simplified properties do not fit accurately enough the real networks. Among the unsatisfactory features are numerically inadequate results, non-stability of algorithms on real (artificial) data, that have been tested on artificial (real) data, and incorrect behavior at different scales. One reason is that randomization and replication of existing structures can create conflicts between fine and coarse scales of the real network geometry. Moreover, the randomization and satisfying of some attribute at the same time can abolish those topological attributes that have been undefined or hidden from researchers. We propose to develop multilevel methods to model complex networks. The key point of the proposed strategy is that it will help to preserve part of the unknown structural attributes by guaranteeing the similar behavior of the real and artificial model on different scales.
Discontinuous Galerkin Method for the Air Pollution Model
Zhao, Lite; Hou, Qinzhi
2011-01-01T23:59:59.000Z
In this paper we present the discontinuous Galerkin method to solve the problem of the two-dimensional air pollution model. The resulting system of ordinary differential equations is called the semidiscrete formulation. We show the existence and uniqueness of the ODE system and provide the error estimates for the numerical error.
March 4 2010 1 Application of Modelling Methods in
Gorban, Alexander N.
March 4 2010 1 Application of Modelling Methods in Wind Turbine Engineering Andrej Horvat and dwindling fossil fuels are making zero-head wind and water turbines increasingly important as renewable been looking at advancing free stream turbine performance to achieve economic competitiveness
Li, Dongsheng; Li, Yulan; Hu, Shenyang Y.; Sun, Xin; Khaleel, Mohammad A.
2012-03-01T23:59:59.000Z
A multiscale methodology was developed to predict the evolution of thermal conductivity of polycrystalline fuel under irradiation. In the mesoscale level, phase field model was used to predict the evolution of gas bubble microstructure. Generation of gas atoms and vacancies were taken into consideration. In the macroscopic scale, a statistical continuum mechanics model was applied to predict the anisotropic thermal conductivity evolution during irradiation. Microstructure predicted by phase field model was fed into statistical continuum mechanics model to predict properties and behavior. Influence of irradiation intensity, exposition time and morphology were investigated. This approach provides a deep understanding on microstructure evolution and property prediction from a basic scientific viewpoint.
Hero, Alfred O.
Background Basic methods Model-based algorithms Model-free algorithms RTI Perspectives Conclusions 23, 2015 1 52 #12;Background Basic methods Model-based algorithms Model-free algorithms RTI Coates (McGill) 2 52 #12;Background Basic methods Model-based algorithms Model-free algorithms RTI
Milligan, M R
1996-04-01T23:59:59.000Z
As an intermittent resource, capturing the temporal variation in windpower is an important issue in the context of utility production cost modeling. Many of the production cost models use a method that creates a cumulative probability distribution that is outside the time domain. The purpose of this report is to examine two production cost models that represent the two major model types: chronological and load duration cure models. This report is part of the ongoing research undertaken by the Wind Technology Division of the National Renewable Energy Laboratory in utility modeling and wind system integration.
HyPEP FY06 Report: Models and Methods
DOE report
2006-09-01T23:59:59.000Z
The Department of Energy envisions the next generation very high-temperature gas-cooled reactor (VHTR) as a single-purpose or dual-purpose facility that produces hydrogen and electricity. The Ministry of Science and Technology (MOST) of the Republic of Korea also selected VHTR for the Nuclear Hydrogen Development and Demonstration (NHDD) Project. This research project aims at developing a user-friendly program for evaluating and optimizing cycle efficiencies of producing hydrogen and electricity in a Very-High-Temperature Reactor (VHTR). Systems for producing electricity and hydrogen are complex and the calculations associated with optimizing these systems are intensive, involving a large number of operating parameter variations and many different system configurations. This research project will produce the HyPEP computer model, which is specifically designed to be an easy-to-use and fast running tool for evaluating nuclear hydrogen and electricity production facilities. The model accommodates flexible system layouts and its cost models will enable HyPEP to be well-suited for system optimization. Specific activities of this research are designed to develop the HyPEP model into a working tool, including (a) identifying major systems and components for modeling, (b) establishing system operating parameters and calculation scope, (c) establishing the overall calculation scheme, (d) developing component models, (e) developing cost and optimization models, and (f) verifying and validating the program. Once the HyPEP model is fully developed and validated, it will be used to execute calculations on candidate system configurations. FY-06 report includes a description of reference designs, methods used in this study, models and computational strategies developed for the first year effort. Results from computer codes such as HYSYS and GASS/PASS-H used by Idaho National Laboratory and Argonne National Laboratory, respectively will be benchmarked with HyPEP results in the following years.
IMPROVED NUMERICAL METHODS FOR MODELING RIVER-AQUIFER INTERACTION.
Tidwell, Vincent C.; Sue Tillery; Phillip King
2008-09-01T23:59:59.000Z
A new option for Local Time-Stepping (LTS) was developed to use in conjunction with the multiple-refined-area grid capability of the U.S. Geological Survey's (USGS) groundwater modeling program, MODFLOW-LGR (MF-LGR). The LTS option allows each local, refined-area grid to simulate multiple stress periods within each stress period of a coarser, regional grid. This option is an alternative to the current method of MF-LGR whereby the refined grids are required to have the same stress period and time-step structure as the coarse grid. The MF-LGR method for simulating multiple-refined grids essentially defines each grid as a complete model, then for each coarse grid time-step, iteratively runs each model until the head and flux changes at the interfacing boundaries of the models are less than some specified tolerances. Use of the LTS option is illustrated in two hypothetical test cases consisting of a dual well pumping system and a hydraulically connected stream-aquifer system, and one field application. Each of the hypothetical test cases was simulated with multiple scenarios including an LTS scenario, which combined a monthly stress period for a coarse grid model with a daily stress period for a refined grid model. The other scenarios simulated various combinations of grid spacing and temporal refinement using standard MODFLOW model constructs. The field application simulated an irrigated corridor along the Lower Rio Grande River in New Mexico, with refinement of a small agricultural area in the irrigated corridor.The results from the LTS scenarios for the hypothetical test cases closely replicated the results from the true scenarios in the refined areas of interest. The head errors of the LTS scenarios were much smaller than from the other scenarios in relation to the true solution, and the run times for the LTS models were three to six times faster than the true models for the dual well and stream-aquifer test cases, respectively. The results of the field application show that better estimates of daily stream leakage can be made with the LTS simulation, thereby improving the efficiency of daily operations for an agricultural irrigation system. ACKNOWLEDGEMENTSThe authors appreciatively acknowledge support for Sue Tillery provided by Sandia National Laboratories' through a Campus Executive Laboratory Directed Research and Development (LDRD) research project.Funding for this study was provided by Directed Research and Development (LDRD) research project.
Topic Models: A Novel Method for Modeling Couple and Family David C. Atkins
Steyvers, Mark
of California, Los Angeles Couple and family researchers often collect open-ended linguistic data participants' responses are not forced into a set number of categories, text-based data can be very richTopic Models: A Novel Method for Modeling Couple and Family Text Data David C. Atkins University
Integrated approaches to the optimal design of multiscale systems
Lovelady, Eva Marie
2009-05-15T23:59:59.000Z
This work is aimed at development of systematic approaches to the design of multiscale systems. Specifically four problems are addressed: environmental impact assessment (EIA) of new and retrofitted industrial processes, ...
A multiscale approximation algorithm for the cardinality constrained knapsack problem
Krishnan, Bharath Kumar
2006-01-01T23:59:59.000Z
I develop a multiscale approximation algorithm for the cardinality constrained knapsack problem. The algorithm consists of three steps: a rounding and reduction step where a hierarchical representation of the problem data ...
Integrated approaches to the optimal design of multiscale systems
Lovelady, Eva Marie
2009-05-15T23:59:59.000Z
This work is aimed at development of systematic approaches to the design of multiscale systems. Specifically four problems are addressed: environmental impact assessment (EIA) of new and retrofitted industrial processes, integration of process...
The linear and nonlinear rheology of multiscale complex fluids
Jaishankar, Aditya
2014-01-01T23:59:59.000Z
The microstructures of many complex fluids are typically characterized by a broad distribution of internal length scales. Examples of such multiscale materials include physically and chemically cross-linked gels, emulsions, ...
Electrowetting and droplet impalement experiments on superhydrophobic multiscale
Brunet, Philippe
Electrowetting and droplet impalement experiments on superhydrophobic multiscale structures F925544c The reversible actuation of droplets on superhydrophobic surfaces under ambient conditions. Introduction The superhydrophobic character of a surface generally arises from an interplay between the surface
Cryptic Faulting and Multi-Scale Geothermal Fluid Connections...
from Mt Resistivity Surveying Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Cryptic Faulting and Multi-Scale Geothermal Fluid Connections in...
Dombroski, M; Melius, C; Edmunds, T; Banks, L E; Bates, T; Wheeler, R
2008-09-24T23:59:59.000Z
This study uses the Multi-scale Epidemiologic Simulation and Analysis (MESA) system developed for foreign animal diseases to assess consequences of nationwide human infectious disease outbreaks. A literature review identified the state of the art in both small-scale regional models and large-scale nationwide models and characterized key aspects of a nationwide epidemiological model. The MESA system offers computational advantages over existing epidemiological models and enables a broader array of stochastic analyses of model runs to be conducted because of those computational advantages. However, it has only been demonstrated on foreign animal diseases. This paper applied the MESA modeling methodology to human epidemiology. The methodology divided 2000 US Census data at the census tract level into school-bound children, work-bound workers, elderly, and stay at home individuals. The model simulated mixing among these groups by incorporating schools, workplaces, households, and long-distance travel via airports. A baseline scenario with fixed input parameters was run for a nationwide influenza outbreak using relatively simple social distancing countermeasures. Analysis from the baseline scenario showed one of three possible results: (1) the outbreak burned itself out before it had a chance to spread regionally, (2) the outbreak spread regionally and lasted a relatively long time, although constrained geography enabled it to eventually be contained without affecting a disproportionately large number of people, or (3) the outbreak spread through air travel and lasted a long time with unconstrained geography, becoming a nationwide pandemic. These results are consistent with empirical influenza outbreak data. The results showed that simply scaling up a regional small-scale model is unlikely to account for all the complex variables and their interactions involved in a nationwide outbreak. There are several limitations of the methodology that should be explored in future work including validating the model against reliable historical disease data, improving contact rates, spread methods, and disease parameters through discussions with epidemiological experts, and incorporating realistic behavioral assumptions.
Next Generation Multi-Scale Quantum Simulation Software for Strongly Correlated Materials
Jarrell, Mark
2014-11-18T23:59:59.000Z
The goal of this project was to develop a new formalism for the correlated electron problem, which we call, the Multi Scale Many Body formalism. This report will focus on the work done at the Louisiana State University (LSU) since the mid term report. The LSU group moved from the University of Cincinnati (UC) to LSU in the summer of 2008. In the last full year at UC, only half of the funds were received and it took nearly two years for the funds to be transferred from UC to LSU . This effectively shut down the research at LSU until the transfer was completed in 2011, there were also two no-cost extensions of the grant until August of this year. The grant ended for the other SciDAC partners at Davis and ORNL in 2011. Since the mid term report, the LSU group has published 19 papers [P1-P19] acknowledging this SciDAC, which are listed below. In addition, numerous invited talked acknowledged the SciDAC. Below, we will summarize the work at LSU since the mid-term report and mainly since funding resumed. The projects include the further development of multi-scale methods for correlated systems (1), the study of quantum criticality at finite doping in the Hubbard model (2), the description of a promising new method to study Anderson localization with a million-fold reduction of computational complexity!, the description of other projects (4), and (5) a workshop to close out the project that brought together exascale program developers (Stellar, MPI, OpenMP,...) with applications developers.
Multiscale Analysis of the Gradient of Linear Polarisation
Robitaille, J -F
2015-01-01T23:59:59.000Z
We propose a new multiscale method to calculate the amplitude of the gradient of the linear polarisation vector using a wavelet-based formalism. We demonstrate this method using a field of the Canadian Galactic Plane Survey (CGPS) and show that the filamentary structure typically seen in gradients of linear polarisation maps depends strongly on the instrumental resolution. Our analysis reveals that different networks of filaments are present on different angular scales. The wavelet formalism allows us to calculate the power spectrum of the fluctuations seen in gradients of linear polarisation maps and to determine the scaling behaviour of this quantity. The power spectrum is found to follow a power law with gamma ~ 2.1. We identify a small drop in power between scales of 80 well to the overlap in the u-v plane between the Effelsberg 100-m telescope and the DRAO 26-m telescope data. We suggest that this drop is due to undersampling present in the 26-m telescope data. I...
Trabanino, Rene J; Vaidehi, Nagarajan; Hall, Spencer E; Goddard, William A; Floriano, Wely
2013-02-05T23:59:59.000Z
The invention provides computer-implemented methods and apparatus implementing a hierarchical protocol using multiscale molecular dynamics and molecular modeling methods to predict the presence of transmembrane regions in proteins, such as G-Protein Coupled Receptors (GPCR), and protein structural models generated according to the protocol. The protocol features a coarse grain sampling method, such as hydrophobicity analysis, to provide a fast and accurate procedure for predicting transmembrane regions. Methods and apparatus of the invention are useful to screen protein or polynucleotide databases for encoded proteins with transmembrane regions, such as GPCRs.
Atmospheric Environment 38 (2004) 44274436 Statistical comparison of observed and CMAQ modeled daily
Jun, Mikyoung
2004-01-01T23:59:59.000Z
2004 Abstract New statistical procedures to evaluate the Models-3/Community Multiscale Air Quality reserved. Keywords: Air quality model; Model evaluation; Spacetime process; Separable covariance function 1. Introduction The Models-3/Community Multiscale Air Quality (CMAQ) modeling system has been
Andersohn, Alexander
2013-08-27T23:59:59.000Z
-suited for multiscale modeling, I came across the term representative volume element (or RVE) used commonly in biomaterials. Not finding a definition for the mesoscale well-suited for the aim of multiscale modeling, an alternative definition was provided herein... are similar, there are some clear differences. The differences outlined in this section are evidence that a new definition for the mesoscale, tailored for multiscale modeling, was needed. Some elements of the RVE, which is mostly used in biomaterials...
Progress in Fast, Accurate Multi-scale Climate Simulations
Collins, William D [Lawrence Berkeley National Laboratory (LBNL); Johansen, Hans [Lawrence Berkeley National Laboratory (LBNL); Evans, Katherine J [ORNL; Woodward, Carol S. [Lawrence Livermore National Laboratory (LLNL); Caldwell, Peter [Lawrence Livermore National Laboratory (LLNL)
2015-01-01T23:59:59.000Z
We present a survey of physical and computational techniques that have the potential to con- tribute to the next generation of high-fidelity, multi-scale climate simulations. Examples of the climate science problems that can be investigated with more depth include the capture of remote forcings of localized hydrological extreme events, an accurate representation of cloud features over a range of spatial and temporal scales, and parallel, large ensembles of simulations to more effectively explore model sensitivities and uncertainties. Numerical techniques, such as adaptive mesh refinement, implicit time integration, and separate treatment of fast physical time scales are enabling improved accuracy and fidelity in simulation of dynamics and allow more complete representations of climate features at the global scale. At the same time, part- nerships with computer science teams have focused on taking advantage of evolving computer architectures, such as many-core processors and GPUs, so that these approaches which were previously considered prohibitively costly have become both more efficient and scalable. In combination, progress in these three critical areas is poised to transform climate modeling in the coming decades.
Progress in fast, accurate multi-scale climate simulations
Collins, W. D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Johansen, H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Evans, K. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Woodward, C. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Caldwell, P. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2015-01-01T23:59:59.000Z
We present a survey of physical and computational techniques that have the potential to contribute to the next generation of high-fidelity, multi-scale climate simulations. Examples of the climate science problems that can be investigated with more depth with these computational improvements include the capture of remote forcings of localized hydrological extreme events, an accurate representation of cloud features over a range of spatial and temporal scales, and parallel, large ensembles of simulations to more effectively explore model sensitivities and uncertainties. Numerical techniques, such as adaptive mesh refinement, implicit time integration, and separate treatment of fast physical time scales are enabling improved accuracy and fidelity in simulation of dynamics and allowing more complete representations of climate features at the global scale. At the same time, partnerships with computer science teams have focused on taking advantage of evolving computer architectures such as many-core processors and GPUs. As a result, approaches which were previously considered prohibitively costly have become both more efficient and scalable. In combination, progress in these three critical areas is poised to transform climate modeling in the coming decades.
Progress in fast, accurate multi-scale climate simulations
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Collins, W. D.; Johansen, H.; Evans, K. J.; Woodward, C. S.; Caldwell, P. M.
2015-01-01T23:59:59.000Z
We present a survey of physical and computational techniques that have the potential to contribute to the next generation of high-fidelity, multi-scale climate simulations. Examples of the climate science problems that can be investigated with more depth with these computational improvements include the capture of remote forcings of localized hydrological extreme events, an accurate representation of cloud features over a range of spatial and temporal scales, and parallel, large ensembles of simulations to more effectively explore model sensitivities and uncertainties. Numerical techniques, such as adaptive mesh refinement, implicit time integration, and separate treatment of fast physical time scales are enablingmore »improved accuracy and fidelity in simulation of dynamics and allowing more complete representations of climate features at the global scale. At the same time, partnerships with computer science teams have focused on taking advantage of evolving computer architectures such as many-core processors and GPUs. As a result, approaches which were previously considered prohibitively costly have become both more efficient and scalable. In combination, progress in these three critical areas is poised to transform climate modeling in the coming decades.« less
Combining Coarse-Grained Protein Models with Replica-Exchange All-Atom Molecular Dynamics
Wabik, Jacek; Gront, Dominik; Kouza, Maksim; Kolinski, Andrzej
2013-01-01T23:59:59.000Z
We describe a combination of all-atom simulations with CABS, a well-established coarse-grained protein modeling tool, into a single multiscale protocol. The simulation method has been tested on the C-terminal beta hairpin of protein G, a model system of protein folding. After reconstructing atomistic details, conformations derived from the CABS simulation were subjected to replica-exchange molecular dynamics simulations with OPLS-AA and AMBER99sb force fields in explicit solvent. Such a combination accelerates system convergence several times in comparison with all-atom simulations starting from the extended chain conformation, demonstrated by the analysis of melting curves, the number of native-like conformations as a function of time and secondary structure propagation. The results strongly suggest that the proposed multiscale method could be an efficient and accurate tool for high-resolution studies of protein folding dynamics in larger systems.
Stochastic multiscale fracture analysis of three-dimensional functionally graded composites
Rahman, Sharif
Stochastic multiscale fracture analysis of three-dimensional functionally graded composites Sharif: Probabilistic fracture mechanics Polynomial dimensional decomposition Random microstructure Reliability a b for stochastic multiscale fracture analysis of three-dimensional, particle-matrix, functionally graded materials
Leus, Geert
incident angles. The former gives rise to the multi-lag effect; the latter implies that the radial velocity Doppler effects (manifested in signal scales) and time of arrivals (manifested in lags). We capture such an effect in this paper with a multi-scale multi-lag (MSML) model, and show that the resulting frequency
Assessment of Molecular Modeling & Simulation
None
2002-01-03T23:59:59.000Z
This report reviews the development and applications of molecular and materials modeling in Europe and Japan in comparison to those in the United States. Topics covered include computational quantum chemistry, molecular simulations by molecular dynamics and Monte Carlo methods, mesoscale modeling of material domains, molecular-structure/macroscale property correlations like QSARs and QSPRs, and related information technologies like informatics and special-purpose molecular-modeling computers. The panel's findings include the following: The United States leads this field in many scientific areas. However, Canada has particular strengths in DFT methods and homogeneous catalysis; Europe in heterogeneous catalysis, mesoscale, and materials modeling; and Japan in materials modeling and special-purpose computing. Major government-industry initiatives are underway in Europe and Japan, notably in multi-scale materials modeling and in development of chemistry-capable ab-initio molecular dynamics codes.
Application of the Asymptotic Iteration Method to a Perturbed Coulomb Model
Paolo Amore; Francisco M. Fernandez
2006-04-17T23:59:59.000Z
We show that the asymptotic iteration method converges and yields accurate energies for a perturbed Coulomb model. We also discuss alternative perturbation approaches to that model.
A comparison between the fission matrix method, the diffusion model and the transport model
Dehaye, B.; Hugot, F. X.; Diop, C. M. [Commissariat a l'Energie Atomique et aux Energies Alternatives, Direction de l'Energie Nucleaire, Departement de Modelisation des Systemes et Structures, CEA DEN/DM2S, PC 57, F-91191 Gif-sur-Yvette cedex (France)
2013-07-01T23:59:59.000Z
The fission matrix method may be used to solve the critical eigenvalue problem in a Monte Carlo simulation. This method gives us access to the different eigenvalues and eigenvectors of the transport or fission operator. We propose to compare the results obtained via the fission matrix method with those of the diffusion model, and an approximated transport model. To do so, we choose to analyse the mono-kinetic and continuous energy cases for a Godiva-inspired critical sphere. The first five eigenvalues are computed with TRIPOLI-4{sup R} and compared to the theoretical ones. An extension of the notion of the extrapolation distance is proposed for the modes other than the fundamental one. (authors)
5, 755794, 2005 Reduction methods
Paris-Sud XI, Université de
ACPD 5, 755794, 2005 Reduction methods for chemical schemes S. Szopa et al. Title Page Abstract Assessment of the reduction methods used to develop chemical schemes: building of a new chemical scheme for VOC oxidation suited to three-dimensional multiscale HOx-NOx-VOC chemistry simulations S. Szopa 1
Modeling and Test-and-Rate Methods for Innovative Thermosiphon Solar Water Heaters: Preprint
Burch, J.; Shoukas, G.; Brandemuhl, M.; Krarti, M.
2006-05-01T23:59:59.000Z
Conference paper regarding research in modeling and test-and-rate methods for thermosiphon solar domestic water heaters.
Memory of jamming - multiscale flow in soft and granular matter
Nishant Kumar; Stefan Luding
2015-07-29T23:59:59.000Z
Soft, disordered, micro-structured materials are ubiquitous in nature and industry, and are different from ordinary fluids or solids, with unusual, interesting flow properties. The transition from fluid to solid - at the so-called jamming density - features a multitude of complex mechanisms, but there is no unified theoretical framework that explains them all. In this study, a simple yet quantitative and predictive model is presented, which allows for a changing jamming density, encompassing the memory of the deformation history and explaining a multitude of flow phenomena at and around jamming. The jamming density, introduced as a new state-variable, changes due to the deformation history and relates the system's macroscopic response to its micro-structure. The packing efficiency can increase logarithmically slow under gentle "tapping" or repeated (isotropic) compression, leading to an increase of the jamming density. In contrast, shear deformations cause anisotropy, changing the packing efficiency exponentially fast with either dilatancy or compactancy. The memory of the system near jamming can be explained by a micro-statistical model that involves a multiscale, fractal energy landscape and links the microscopic particle picture to the macroscopic continuum description, providing a unified explanation for the qualitatively different flow-behavior for different deformation modes. To complement our work, a recipe to extract the history-dependent jamming density from experimentally accessible data is proposed, and alternative state-variables are compared. The proposed simple, usable macroscopic model, will help predicting and avoiding geophysical hazards, bring forward industrial process design and optimization, and understand and solve scientific challenges in fundamental research.
Jun, Gyuchan T; Morris, Zoe; Eldabi, Tillal; Harper, Paul; Naseer, Aisha; Patel, Brijesh; Clarkson, John P
2011-05-19T23:59:59.000Z
Simulation, Mathematical Programming/Optimisation Methods, Markov Models, Queuing Theory, Structural Equation Modelling, System Dynamics, Process Mapping, Spatial Mapping, Monte Carlo Simulation, Cognitive Mapping, Soft Systems Methodology 2. Simulation... analysis Table 2 Twenty eight methods identified for the selection tool Categories No. Methods Problem Structuring Methods 1 Drama Theory & Confrontation Analysis 2 Robustness Analysis 3 Soft Systems Methodology 4 Strategic Choice Approach 5 Strategic...
WIDE-FIELD ASTRONOMICAL MULTISCALE CAMERAS
Marks, Daniel L.; Brady, David J., E-mail: dbrady@ee.duke.edu [Department of Electrical and Computer Engineering and Fitzpatrick Institute for Photonics, Box 90291, Duke University, Durham, NC 27708 (United States)
2013-05-15T23:59:59.000Z
In order to produce sufficiently low aberrations with a large aperture, telescopes have a limited field of view. Because of this narrow field, large areas of the sky at a given time are unobserved. We propose several telescopes based on monocentric reflective, catadioptric, and refractive objectives that may be scaled to wide fields of view and achieve 1.''1 resolution, which in most locations is the practical seeing limit of the atmosphere. The reflective and Schmidt catadioptric objectives have relatively simple configurations and enable large fields to be captured at the expense of the obscuration of the mirror by secondary optics, a defect that may be managed by image plane design. The refractive telescope design does not have an obscuration but the objective has substantial bulk. The refractive design is a 38 gigapixel camera which consists of a single monocentric objective and 4272 microcameras. Monocentric multiscale telescopes, with their wide fields of view, may observe phenomena that might otherwise be unnoticed, such as supernovae, glint from orbital space debris, and near-earth objects.
Uncertainty quantification using multiscale methods for porous media flows
Dostert, Paul Francis
2009-05-15T23:59:59.000Z
permeability we use L1 = 0.5, L2 = 0.1 and ?2 = 2.0. . . . . . . . . . 15 2.7 Example boundary conditions for local upscaling problem. The upper left demonstrates boundary conditions in the x-direction and the upper right demonstrates boundary conditions....3)) restricted to the same 2-D hyperplane. . . . . . . . . . . . 89 6.2 Acceptance rate comparison between Algorithms I, II and III; ? = 0.05, ?2f = 0.003. In the left plot, the coarse-grid 11? 11 is used in the simulation...
International Workshop Multiscale Methods for Fluid and Plasma Turbulence
Schneider, Kai
Bob Krasny, USA David Montgomery, USA Volker Naulin, Denmark Caroline Nore, France Assad Oberai, USA
Multiscale numerical methods for some types of parabolic equations
Nam, Dukjin
2009-05-15T23:59:59.000Z
,Dxvhbardblp/(p?s)UK +Cbardbl??Dt ?N?vh,DxvhbardblqV? K (2.18) We will show the convergence of the last two terms in (2.18) separately. 21 Step 1. First we study bardbl??Dx ?N?vh,DxvhbardblpUK. Let JK?[tn,tn+1]? = {i ? Zd+1 : (Y? ? T0,?)i ? (K ? [tn,tn+1]) negationslash= ?,(Y... i (1 +|?vh|p +|Dxvh|p)|(Y? ?T0,?)i| ? C parenleftbigg?? ?1 parenrightbiggp hd xht hdxht(1 +|? vh|p +|Dxvh|p)(hd?1 x ?1ht +h d x?2) ? C parenleftbigg?? ?1 parenrightbiggpparenleftbigg? 1 hx + ?2 ht parenrightbigg (|K?[tn,tn+1]|+bardbl...
The LATIN multiscale computational method and the Proper Generalized Decomposition
drastically and presents some sim- ilarities with the POD. Initially introduced for the analyze and reduction numbers of degrees of freedom and the corresponding calcula- tion costs are generally prohibitive. There and the macroscale. A new micro/macro computational strat- egy was proposed in [18] which involved space and time
Identification of Rational Functions using two-degree-of-freedom model by forced vibration method
McCalley, James D.
Identification of Rational Functions using two-degree-of-freedom model by forced vibration method Functions Self-excited forces Two-degree-of-freedom model Forced vibration method Streamlined section model the Rational Functions from wind tunnel section model tests in free vibration. To overcome the limitations
Neural node network and model, and method of teaching same
Parlos, Alexander G. (College Station, TX); Atiya, Amir F. (College Station, TX); Fernandez, Benito (Austin, TX); Tsai, Wei K. (Irvine, CA); Chong, Kil T. (College Station, TX)
1995-01-01T23:59:59.000Z
The present invention is a fully connected feed forward network that includes at least one hidden layer 16. The hidden layer 16 includes nodes 20 in which the output of the node is fed back to that node as an input with a unit delay produced by a delay device 24 occurring in the feedback path 22 (local feedback). Each node within each layer also receives a delayed output (crosstalk) produced by a delay unit 36 from all the other nodes within the same layer 16. The node performs a transfer function operation based on the inputs from the previous layer and the delayed outputs. The network can be implemented as analog or digital or within a general purpose processor. Two teaching methods can be used: (1) back propagation of weight calculation that includes the local feedback and the crosstalk or (2) more preferably a feed forward gradient decent which immediately follows the output computations and which also includes the local feedback and the crosstalk. Subsequent to the gradient propagation, the weights can be normalized, thereby preventing convergence to a local optimum. Education of the network can be incremental both on and off-line. An educated network is suitable for modeling and controlling dynamic nonlinear systems and time series systems and predicting the outputs as well as hidden states and parameters. The educated network can also be further educated during on-line processing.
Neural node network and model, and method of teaching same
Parlos, A.G.; Atiya, A.F.; Fernandez, B.; Tsai, W.K.; Chong, K.T.
1995-12-26T23:59:59.000Z
The present invention is a fully connected feed forward network that includes at least one hidden layer. The hidden layer includes nodes in which the output of the node is fed back to that node as an input with a unit delay produced by a delay device occurring in the feedback path (local feedback). Each node within each layer also receives a delayed output (crosstalk) produced by a delay unit from all the other nodes within the same layer. The node performs a transfer function operation based on the inputs from the previous layer and the delayed outputs. The network can be implemented as analog or digital or within a general purpose processor. Two teaching methods can be used: (1) back propagation of weight calculation that includes the local feedback and the crosstalk or (2) more preferably a feed forward gradient decent which immediately follows the output computations and which also includes the local feedback and the crosstalk. Subsequent to the gradient propagation, the weights can be normalized, thereby preventing convergence to a local optimum. Education of the network can be incremental both on and off-line. An educated network is suitable for modeling and controlling dynamic nonlinear systems and time series systems and predicting the outputs as well as hidden states and parameters. The educated network can also be further educated during on-line processing. 21 figs.
ADVANCED METHODS OF FLUX IDENTIFICATION FOR CLARIFIER-THICKENER SIMULATION MODELS
Bürger, Raimund
models for the batch and continuous sedimentation of finely divided solid particles dispersed-liquid separation, thickener simulation, batch sedimentation, flux identifi- cation, mathematical model. PresentedADVANCED METHODS OF FLUX IDENTIFICATION FOR CLARIFIER-THICKENER SIMULATION MODELS FERNANDO
Multi-scale analysis of lung computed tomography images
Gori, I; Fantacci, M E; Martinez, A Preite; Retico, A; De Mitri, I; Donadio, S; Fulcheri, C; Gargano, G; Magro, R; Santoro, M; Stumbo, S; 10.1088/1748-0221/2/09/P09007
2009-01-01T23:59:59.000Z
A computer-aided detection (CAD) system for the identification of lung internal nodules in low-dose multi-detector helical Computed Tomography (CT) images was developed in the framework of the MAGIC-5 project. The three modules of our lung CAD system, a segmentation algorithm for lung internal region identification, a multi-scale dot-enhancement filter for nodule candidate selection and a multi-scale neural technique for false positive finding reduction, are described. The results obtained on a dataset of low-dose and thin-slice CT scans are shown in terms of free response receiver operating characteristic (FROC) curves and discussed.
Testing Generalized Linear Models Using Smoothing Spline Methods
Wang, Yuedong
the hypothesis of Generalized Linear Models (GLM) versus general smoothing spline models for data from exponential families. The tests developed are based on the connection between the smoothing spline models and residual plots are less informative for discrete data. Therefore general diagnostic and model building
Neighborhood analysis methods in acoustic modeling for automatic speech recognition
Singh-Miller, Natasha, 1981-
2010-01-01T23:59:59.000Z
This thesis investigates the problem of using nearest-neighbor based non-parametric methods for performing multi-class class-conditional probability estimation. The methods developed are applied to the problem of acoustic ...
Simplified modeling methods for mechanically fastened connections in flight structures
Brewer, Brett Andrew
2012-01-01T23:59:59.000Z
load sharing, failure modes, and basic design are outlined such that later developments in the finite element method
Li, Haijun
such as quantitative risk management, decision analysis under uncertainty, and their applications in areas methods developed for reliability modeling and risk analysis. Reliability theory and risk analysis have. This special volume highlights this convergence of reliability modeling and risk analysis, that forms the core
Multi-Scale Initial Conditions For Cosmological Simulations
Hahn, Oliver; /KIPAC, Menlo Park; Abel, Tom; /KIPAC, Menlo Park /ZAH, Heidelberg /HITS, Heidelberg
2011-11-04T23:59:59.000Z
We discuss a new algorithm to generate multi-scale initial conditions with multiple levels of refinements for cosmological 'zoom-in' simulations. The method uses an adaptive convolution of Gaussian white noise with a real-space transfer function kernel together with an adaptive multi-grid Poisson solver to generate displacements and velocities following first- (1LPT) or second-order Lagrangian perturbation theory (2LPT). The new algorithm achieves rms relative errors of the order of 10{sup -4} for displacements and velocities in the refinement region and thus improves in terms of errors by about two orders of magnitude over previous approaches. In addition, errors are localized at coarse-fine boundaries and do not suffer from Fourier-space-induced interference ringing. An optional hybrid multi-grid and Fast Fourier Transform (FFT) based scheme is introduced which has identical Fourier-space behaviour as traditional approaches. Using a suite of re-simulations of a galaxy cluster halo our real-space-based approach is found to reproduce correlation functions, density profiles, key halo properties and subhalo abundances with per cent level accuracy. Finally, we generalize our approach for two-component baryon and dark-matter simulations and demonstrate that the power spectrum evolution is in excellent agreement with linear perturbation theory. For initial baryon density fields, it is suggested to use the local Lagrangian approximation in order to generate a density field for mesh-based codes that is consistent with the Lagrangian perturbation theory instead of the current practice of using the Eulerian linearly scaled densities.
Error Control Based Model Reduction for Parameter Optimization of Elliptic
of technical devices that rely on multiscale processes, such as fuel cells or batteries. As the solutionError Control Based Model Reduction for Parameter Optimization of Elliptic Homogenization Problems optimization of elliptic multiscale problems with macroscopic optimization functionals and microscopic material
Interactive Multiscale Classification of High-Resolution Remote Sensing Images
Gosselin, Philippe-Henri
1 Interactive Multiscale Classification of High-Resolution Remote Sensing Images Jefersson Alex dos~ao Abstract The use of remote sensing images (RSIs) as a source of information in agribusiness applications in space occupation. However, the identification and recognition of crop regions in remote sensing images
Mechanical Engineering Department Multi-scale optical metrology and
Furlong, Cosme
Mechanical Engineering Department Multi-scale optical metrology and nondestructive testing: CAMET;Mechanical Engineering Department Motivation: production cycle with CAD/CAE/CAM support CAD/CAE Computer #12;Mechanical Engineering Department 200 mm Microscale and Nanoscale Macroscale Actual blade
Hydraulic Fractures: multiscale phenomena, asymptotic and numerical solutions
Peirce, Anthony
Hydraulic Fractures: multiscale phenomena, asymptotic and numerical solutions SANUM Conference (UMN) Eduard Siebrits (SLB) #12;2 Outline · Examples of hydraulic fractures · Governing equations Energy Breaking rock Leak-off Viscous energy loss #12;10 2-3D HF Equations · Elasticity · Lubrication
Wax Segregation in Oils: A Multiscale Mario Primicerio
Primicerio, Mario
Wax Segregation in Oils: A Multiscale Problem. Mario Primicerio Department of Mathematics "Ulisse the behaviour of a real oil. It is a mixture of a given standard "wax" and a "solvent" (decane). The wax we/dissolution of wax For any waxy crude oil, and in particular for our "ideal mixture" with a given wax concentration c
Development of a Model to Compare Emergency Chemical Decontamination Methods
Bradley, Richard N; Huff, Ester N
2008-01-01T23:59:59.000Z
Emergency Chemical Decontamination Methods Richard N.the clothing even after decontamination. Additionally, whileon the skin before decontamination, we found significant
Robust Linearization of RF Amplifiers Using NonLinear Internal Model Control Method
Paris-Sud XI, Université de
Robust Linearization of RF Amplifiers Using NonLinear Internal Model Control Method Smail Bachir #1, the nonlinear Internal Model Control (IMC) method is introduced and applied to linearize high frequency Power to be controlled [8]. If the model is a perfect representation of the non linear system, the controller can
Soatto, Stefano
2.10 Multiscale Actuated Sensing (MAS) Multiscale actuated sensing research activities have focused on the trajectory design process for underwater vehicles. We take an Informative Path Planning approach to the robot path-planning problem. We aim to choose measurements that best describe a scalar field of interest (e
A STABILIZED MODEL AND AN EFFICIENT SOLUTION METHOD ...
2011-01-28T23:59:59.000Z
We propose a stabilized model for the electricity generation management problem on ... Jours de Pointe in French] contracts in France), the electricity generation ...
Radiation Damage in Nuclear Fuel for Advanced Burner Reactors: Modeling and Experimental Validation
Jensen, Niels Gronbech; Asta, Mark; Ozolins, Nigel Browning'Vidvuds; de Walle, Axel van; Wolverton, Christopher
2011-12-29T23:59:59.000Z
The consortium has completed its existence and we are here highlighting work and accomplishments. As outlined in the proposal, the objective of the work was to advance the theoretical understanding of advanced nuclear fuel materials (oxides) toward a comprehensive modeling strategy that incorporates the different relevant scales involved in radiation damage in oxide fuels. Approaching this we set out to investigate and develop a set of directions: 1) Fission fragment and ion trajectory studies through advanced molecular dynamics methods that allow for statistical multi-scale simulations. This work also includes an investigation of appropriate interatomic force fields useful for the energetic multi-scale phenomena of high energy collisions; 2) Studies of defect and gas bubble formation through electronic structure and Monte Carlo simulations; and 3) an experimental component for the characterization of materials such that comparisons can be obtained between theory and experiment.
Webster, Mort David.; Tatang, Menner A.; McRae, Gregory J.
This paper presents the probabilistic collocation method as a computationally efficient method for performing uncertainty analysis on large complex models such as those used in global climate change research. The collocation ...
Lee, Kyoung-Jin
2006-08-16T23:59:59.000Z
the wavefront construction method. Modeling with wavefront construction code is applied to anisotropic media as well as isotropic media. Synthetic seismograms are computed using the wavefront construction method as a new way of generating synthetics...
Accelerated Iterative Method for Solving Steady Solutions of Linearized Atmospheric Models
Watanabe, Masahiro
Accelerated Iterative Method for Solving Steady Solutions of Linearized Atmospheric Models Masahiro approach, referred to as the accelerated iterative method (AIM), is developed for solving steady state, respectively. For ensuring the accelerated asymptotic convergence of iterative procedure
A Conformal Mapping Grid Generation Method for Modeling High-Fidelity Aeroelastic Simulations
Worley, Gregory
2010-07-14T23:59:59.000Z
This work presents a method for building a three-dimensional mesh from two- dimensional topologically identical layers, for use in aeroelastic simulations. The method allows modeling of large deformations of the wing in ...
Interconnected hydro-thermal systems Models, methods, and applications
. The study has been financed by the Danish Academy of Technical Sciences (ATV) and Elkraft System-thermal power systems. One of the main goals of the study has been the development of modelling tools modelling applied to power system analysis within an international perspective. It consists of two parts
Modeling of the Aging Viscoelastic Properties of Cement Paste Using Computational Methods
Li, Xiaodan
2012-07-16T23:59:59.000Z
computational model using finite element method to predict the viscoelastic behavior of cement paste, and using this model, virtual tests can be carried out to improve understanding of the mechanisms of viscoelastic behavior. The primary finding from...
Inference in sensor networks : graphical models and particle methods
Ihler, Alexander T. (Alexander Thomas), 1976-
2005-01-01T23:59:59.000Z
Sensor networks have quickly risen in importance over the last several years to become an active field of research, full of difficult problems and applications. At the same time, graphical models have shown themselves to ...
A Method for Computing Conditional Probabilities in Probabilistic Library Model
, . PLM , in-vitro DNA , , PLM , 1% . PLM . 1. (Probabilistic Library Model) DNA [4], .[2,3] in-vitro DNA , PCR dilution .[1] PLM , . , , DNA , DNA . PLM , .[2, 3] , DNA (wDNF) DNA
Game-Method Model for Field Fires Nina Dobrinkova1
Fidanova, Stefka
Engineering, Bulgarian Academy of Sciences krat@bas.bg Abstract. Every year about 45000 forest fires occur fire. This model can be used also by non specialist in the forest fires field for learn- ing
Multi-scale analysis and simulation of powder blending in pharmaceutical manufacturing
Ngai, Samuel S. H
2005-01-01T23:59:59.000Z
A Multi-Scale Analysis methodology was developed and carried out for gaining fundamental understanding of the pharmaceutical powder blending process. Through experiment, analysis and computer simulations, microscopic ...
Chow, J.C.; Severance, P.W.; Spengler, J.D.
1985-01-01T23:59:59.000Z
The research reported here extends source apportioment techniques by combining four air quality model types to establish multi-scale source/receptor relationships. The selected models are: Branching Atmospheric Trajectory (BAT) model for regional-scale contributors; Principal Component Analysis (PCA) receptor model for urban and regional-scale contributors; Chemical Mass Balance (CMB) receptor model for urban- and regional-scale contributors; Industrial Source Complex Short-Term (ISC-ST) dispersion model for urban-scale contributors. The framework in which these models are placed allows each one to be replaced with better ones when these new models have been demonstrated to be superior. The theoretical basis, previous applications, and the results of model evaluation studies are summarized by Chow in great detail and will not be presented here. The objectives of this research are: to develop a method for multi-scale composite modeling applications; to define the data requirements; and to apportion local and distract pollution sources using the composite modeling strategy. Results from the entire research effort are too lengthy to include here. This paper focuses on CMB portion of the method. Trajectory and Principal Component Analyses were reported earlier.
Building upon Fast Multipole Methods to detect and model organizations
Paris-Sud XI, Université de
is the gravitational constant. Similarly for N bodies of charge q, Coulomb law [Coulomb 1785] describes as structures and organizations of the simulation. We give in this article a method that detects and manages a description of the gravitational field in is Newton law [Newton 1686]: = - - 3 =1 Where
Multiscale Toxicology- Building the Next Generation Tools for Toxicology
Retterer, S. T. [ORNL] [ORNL; Holsapple, M. P. [Battelle Memorial Institute] [Battelle Memorial Institute
2013-10-31T23:59:59.000Z
A Cooperative Research and Development Agreement (CRADA) was established between Battelle Memorial Institute (BMI), Pacific Northwest National Laboratory (PNNL), Oak Ridge National Laboratory (ORNL), Brookhaven National Laboratory (BNL), Lawrence Livermore National Laboratory (LLNL) with the goal of combining the analytical and synthetic strengths of the National Laboratories with BMI?s expertise in basic and translational medical research to develop a collaborative pipeline and suite of high throughput and imaging technologies that could be used to provide a more comprehensive understanding of material and drug toxicology in humans. The Multi-Scale Toxicity Initiative (MSTI), consisting of the team members above, was established to coordinate cellular scale, high-throughput in vitro testing, computational modeling and whole animal in vivo toxicology studies between MSTI team members. Development of a common, well-characterized set of materials for testing was identified as a crucial need for the initiative. Two research tracks were established by BMI during the course of the CRADA. The first research track focused on the development of tools and techniques for understanding the toxicity of nanomaterials, specifically inorganic nanoparticles (NPs). ORNL?s work focused primarily on the synthesis, functionalization and characterization of a common set of NPs for dissemination to the participating laboratories. These particles were synthesized to retain the same surface characteristics and size, but to allow visualization using the variety of imaging technologies present across the team. Characterization included the quantitative analysis of physical and chemical properties of the materials as well as the preliminary assessment of NP toxicity using commercially available toxicity screens and emerging optical imaging strategies. Additional efforts examined the development of high-throughput microfluidic and imaging assays for measuring NP uptake, localization, and toxicity in vitro. The second research track within the MSTI CRADA focused on the development of ex vivo animal models for examining druginduced cardiotoxicity. ORNL's role in the second track was limited initially, but was later expanded to include the development of microfluidic platforms that might facilitate the translation of Cardiac 'Microwire' technologies developed at the University of Toronto into a functional platform for drug screening and predictive assessment of cardiotoxicity via highthroughput measurements of contractility. This work was coordinated by BMI with the Centre for the Commercialization of Regenerative Medicine (CCRM) and the University of Toronto (U Toronto). This partnership was expanded and culminated in the submission of proposal to Work for Others (WFO) agencies to explore the development of a broader set of microphysiological systems, a so call human-on-a-chip, that could be used for toxicity screening and the evaluation of bio-threat countermeasures.
A Physics Based Method for Combining Multiple Anatomy Models with
Magee, Derek
of Leeds, UK b Mid Yorkshire Hospitals NHS Trust, Wakefield, UK c Leeds Teaching Hospitals NHS Trust, Leeds model is a volumetric segmentation that contains the labelling of the anatomy components of 1Corresponding Author: School of Computing, University of Leeds, UK. E-mail: drm@comp.leeds.ac.uk #12;Current
An Empirical Comparison of Field Defect Modeling Methods
operating system as judged by the Theil forecasting statistic (explained in section 4). We conjecture about Management, Measurement, Reliability, Experimentation, Defect modeling, empirical research, COTS, maintenance-based and metrics-based approach, as judged by the Theil forecasting statistic. We suggest possible conditions
A Nonlinear ModelBased Control Method for Magnetostrictive Actuators
with the field H 0 generated by the permanent magnet. To model the transducer for structural applications the realignment of magnetic moments in response to applied magnetic fields to generate strains in the material to applied magnetic fields. For many ap plications, the magnitude of the generated strains and forces makes
Synthetic Spectrum Methods for Three-Dimensional Supernova Models
R. C. Thomas
2003-10-21T23:59:59.000Z
Current observations stimulate the production of fully three-dimensional explosion models, which in turn motivates three-dimensional spectrum synthesis for supernova atmospheres. We briefly discuss techniques adapted to address the latter problem, and consider some fundamentals of line formation in supernovae without recourse to spherical symmetry. Direct and detailed extensions of the technique are discussed, and future work is outlined.
Three-Dimensional Lithium-Ion Battery Model (Presentation)
Kim, G. H.; Smith, K.
2008-05-01T23:59:59.000Z
Nonuniform battery physics can cause unexpected performance and life degradations in lithium-ion batteries; a three-dimensional cell performance model was developed by integrating an electrode-scale submodel using a multiscale modeling scheme.
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE EDDY CURRENT MODEL WITH CIRCUIT/FIELD COUPLINGS
AN ADAPTIVE FINITE ELEMENT METHOD FOR THE EDDY CURRENT MODEL WITH CIRCUIT/FIELD COUPLINGS JUNQING for solving the eddy current model with voltage excitations for complicated three dimensional structures of the proposed method. Key words. Eddy current, circuit/field coupling, adaptivity, a posteriori error analysis
Numerical Methods for the Bogoliubov-Tolmachev-Shirkov model in superconductivity theory
Zhihao Ge; Ruihua Li
2015-03-08T23:59:59.000Z
In the work, the numerical methods are designed for the Bogoliubov-Tolmachev-Shirkov model in superconductivity theory. The numerical methods are novel and effective to determine the critical transition temperature and approximate to the energy gap function of the above model. Finally, a numerical example confirming the theoretical results is presented.
Economics Definitions, Methods, Models, and Analysis Procedures for Homeland Security Applications
Economics Definitions, Methods, Models, and Analysis Procedures for Homeland Security Applications, Programmer Computational Economics Group January 29, 2010 SAND2010-4315 #12;2 This page intentionally blank #12;3 Economics Definitions, Methods, Models, and Analysis Procedures for Homeland Security
Robertson, Eric P (Idaho Falls, ID); Christiansen, Richard L. (Littleton, CO)
2007-05-29T23:59:59.000Z
A method of optically determining a change in magnitude of at least one dimensional characteristic of a sample in response to a selected chamber environment. A magnitude of at least one dimension of the at least one sample may be optically determined subsequent to altering the at least one environmental condition within the chamber. A maximum change in dimension of the at least one sample may be predicted. A dimensional measurement apparatus for indicating a change in at least one dimension of at least one sample. The dimensional measurement apparatus may include a housing with a chamber configured for accommodating pressure changes and an optical perception device for measuring a dimension of at least one sample disposed in the chamber. Methods of simulating injection of a gas into a subterranean formation, injecting gas into a subterranean formation, and producing methane from a coal bed are also disclosed.
Robertson, Eric P (Idaho Falls, ID); Christiansen, Richard L. (Littleton, CO)
2007-10-23T23:59:59.000Z
A method of optically determining a change in magnitude of at least one dimensional characteristic of a sample in response to a selected chamber environment. A magnitude of at least one dimension of the at least one sample may be optically determined subsequent to altering the at least one environmental condition within the chamber. A maximum change in dimension of the at least one sample may be predicted. A dimensional measurement apparatus for indicating a change in at least one dimension of at least one sample. The dimensional measurement apparatus may include a housing with a chamber configured for accommodating pressure changes and an optical perception device for measuring a dimension of at least one sample disposed in the chamber. Methods of simulating injection of a gas into a subterranean formation, injecting gas into a subterranean formation, and producing methane from a coal bed are also disclosed.
Method of modeling transmissions for real-time simulation
Hebbale, Kumaraswamy V.
2012-09-25T23:59:59.000Z
A transmission modeling system includes an in-gear module that determines an in-gear acceleration when a vehicle is in gear. A shift module determines a shift acceleration based on a clutch torque when the vehicle is shifting between gears. A shaft acceleration determination module determines a shaft acceleration based on at least one of the in-gear acceleration and the shift acceleration.
Yortsos, Y.C.
2001-05-29T23:59:59.000Z
This report is an investigation of various multi-phase and multiscale transport and reaction processes associated with heavy oil recovery. The thrust areas of the project include the following: Internal drives, vapor-liquid flows, combustion and reaction processes, fluid displacements and the effect of instabilities and heterogeneities and the flow of fluids with yield stress. These find respective applications in foamy oils, the evolution of dissolved gas, internal steam drives, the mechanics of concurrent and countercurrent vapor-liquid flows, associated with thermal methods and steam injection, such as SAGD, the in-situ combustion, the upscaling of displacements in heterogeneous media and the flow of foams, Bingham plastics and heavy oils in porous media and the development of wormholes during cold production.
The Hamiltonian Particle-Mesh (HPM) method for numerical modeling of atmospheric flows.
Kim, Guebuem
The Hamiltonian Particle-Mesh (HPM) method for numerical modeling of atmospheric flows. Seoleun Shin 15. Feb. 2011 Abstract The Hamiltonian Particle-Mesh (HPM) method is an interesting alternative have developed schemes based on the HPM method for the shallow-water equations on the sphere, nonhydro
Zabaras, Nicholas J.
MODELING OF MICROSTRUCTURE EVOLUTION IN MULTICOMPONENT ALLOYS USING THE LEVEL SET METHOD Sibley School of Mechanical and Aerospace Engineering 188 Frank H. T. Rhodes Hall Cornell University-component alloy, Microstructure, Solidification. A level set method combining features of front tracking methods
Synthesis of Numerical Methods for Modeling Wave Energy Converter-Point Absorbers: Preprint
Li, Y.; Yu, Y. H.
2012-05-01T23:59:59.000Z
During the past few decades, wave energy has received significant attention among all ocean energy formats. Industry has proposed hundreds of prototypes such as an oscillating water column, a point absorber, an overtopping system, and a bottom-hinged system. In particular, many researchers have focused on modeling the floating-point absorber as the technology to extract wave energy. Several modeling methods have been used such as the analytical method, the boundary-integral equation method, the Navier-Stokes equations method, and the empirical method. However, no standardized method has been decided. To assist the development of wave energy conversion technologies, this report reviews the methods for modeling the floating-point absorber.
System and method for modeling and analyzing complex scenarios
Shevitz, Daniel Wolf
2013-04-09T23:59:59.000Z
An embodiment of the present invention includes a method for analyzing and solving possibility tree. A possibility tree having a plurality of programmable nodes is constructed and solved with a solver module executed by a processor element. The solver module executes the programming of said nodes, and tracks the state of at least a variable through a branch. When a variable of said branch is out of tolerance with a parameter, the solver disables remaining nodes of the branch and marks the branch as an invalid solution. The valid solutions are then aggregated and displayed as valid tree solutions.
Lifetime statistics of quantum chaos studied by a multiscale analysis
Di Falco, A.; Krauss, T. F. [School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS (United Kingdom); Fratalocchi, A. [PRIMALIGHT, Faculty of Electrical Engineering, Applied Mathematics and Computational Science, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia)
2012-04-30T23:59:59.000Z
In a series of pump and probe experiments, we study the lifetime statistics of a quantum chaotic resonator when the number of open channels is greater than one. Our design embeds a stadium billiard into a two dimensional photonic crystal realized on a silicon-on-insulator substrate. We calculate resonances through a multiscale procedure that combines energy landscape analysis and wavelet transforms. Experimental data is found to follow the universal predictions arising from random matrix theory with an excellent level of agreement.
S. Adamenko; V. Bolotov; V. Novikov
2013-07-17T23:59:59.000Z
Physical fundamentals of the self-organizing theory for the system with varying constraints are considered. A variation principle, specifically the principle of dynamic harmonization as a generalization of the Gauss-Hertz principle for the systems with varying internal structure is formulated. In compliance with this principle the system evolves through dynamics of the processes leading to harmonization of the internal multiscale structure of the system and its connections with external actions as a result of minimizing the dynamic harmonization function. Main principles of the shell model of self-organization under the action of the dominating entropic disturbance are formulated.
Review of Wind Energy Forecasting Methods for Modeling Ramping Events
Wharton, S; Lundquist, J K; Marjanovic, N; Williams, J L; Rhodes, M; Chow, T K; Maxwell, R
2011-03-28T23:59:59.000Z
Tall onshore wind turbines, with hub heights between 80 m and 100 m, can extract large amounts of energy from the atmosphere since they generally encounter higher wind speeds, but they face challenges given the complexity of boundary layer flows. This complexity of the lowest layers of the atmosphere, where wind turbines reside, has made conventional modeling efforts less than ideal. To meet the nation's goal of increasing wind power into the U.S. electrical grid, the accuracy of wind power forecasts must be improved. In this report, the Lawrence Livermore National Laboratory, in collaboration with the University of Colorado at Boulder, University of California at Berkeley, and Colorado School of Mines, evaluates innovative approaches to forecasting sudden changes in wind speed or 'ramping events' at an onshore, multimegawatt wind farm. The forecast simulations are compared to observations of wind speed and direction from tall meteorological towers and a remote-sensing Sound Detection and Ranging (SODAR) instrument. Ramping events, i.e., sudden increases or decreases in wind speed and hence, power generated by a turbine, are especially problematic for wind farm operators. Sudden changes in wind speed or direction can lead to large power generation differences across a wind farm and are very difficult to predict with current forecasting tools. Here, we quantify the ability of three models, mesoscale WRF, WRF-LES, and PF.WRF, which vary in sophistication and required user expertise, to predict three ramping events at a North American wind farm.
Piri, Mohammad
2014-03-31T23:59:59.000Z
Under this project, a multidisciplinary team of researchers at the University of Wyoming combined state-of-the-art experimental studies, numerical pore- and reservoir-scale modeling, and high performance computing to investigate trapping mechanisms relevant to geologic storage of mixed scCO{sub 2} in deep saline aquifers. The research included investigations in three fundamental areas: (i) the experimental determination of two-?phase flow relative permeability functions, relative permeability hysteresis, and residual trapping under reservoir conditions for mixed scCO{sub 2}-?brine systems; (ii) improved understanding of permanent trapping mechanisms; (iii) scientifically correct, fine grid numerical simulations of CO{sub 2} storage in deep saline aquifers taking into account the underlying rock heterogeneity. The specific activities included: (1) Measurement of reservoir-?conditions drainage and imbibition relative permeabilities, irreducible brine and residual mixed scCO{sub 2} saturations, and relative permeability scanning curves (hysteresis) in rock samples from RSU; (2) Characterization of wettability through measurements of contact angles and interfacial tensions under reservoir conditions; (3) Development of physically-?based dynamic core-?scale pore network model; (4) Development of new, improved high-? performance modules for the UW-?team simulator to provide new capabilities to the existing model to include hysteresis in the relative permeability functions, geomechanical deformation and an equilibrium calculation (Both pore-? and core-?scale models were rigorously validated against well-?characterized core-? flooding experiments); and (5) An analysis of long term permanent trapping of mixed scCO{sub 2} through high-?resolution numerical experiments and analytical solutions. The analysis takes into account formation heterogeneity, capillary trapping, and relative permeability hysteresis.
Soil cracking modelling using the mesh-free SPH method
Bui, H H; Kodikara, J; Sanchez, M
2015-01-01T23:59:59.000Z
The presence of desiccation cracks in soils can significantly alter their mechanical and hydrological properties. In many circumstances, desiccation cracking in soils can cause significant damage to earthen or soil supported structures. For example, desiccation cracks can act as the preference path way for water flow, which can facilitate seepage flow causing internal erosion inside earth structures. Desiccation cracks can also trigger slope failures and landslides. Therefore, developing a computational procedure to predict desiccation cracking behaviour in soils is vital for dealing with key issues relevant to a range of applications in geotechnical and geo-environment engineering. In this paper, the smoothed particle hydrodynamics (SPH) method will be extended for the first time to simulate shrinkage-induced soil cracking. The main objective of this work is to examine the performance of the proposed numerical approach in simulating the strong discontinuity in material behaviour and to learn about the crack ...
Linear and NonLinear Estimation Methods Applied to the Hemodynamic model
Schaal, Stefan
Linear and NonLinear Estimation Methods Applied to the Hemodynamic model Evangelos A. Theodorou s that controls the blood inflow. The total balloon model can be defined by the 4 differential equations the hemodynamic process of the balloon model. These equations consist of a set of deterministic highly non
FINITE VOLUME METHODS APPLIED TO THE COMPUTATIONAL MODELLING OF WELDING PHENOMENA
Taylor, Gary
1 FINITE VOLUME METHODS APPLIED TO THE COMPUTATIONAL MODELLING OF WELDING PHENOMENA Gareth A.Taylor@brunel.ac.uk ABSTRACT This paper presents the computational modelling of welding phenomena within a versatile numerical) and Computational Solid Mechanics (CSM). With regard to the CFD modelling of the weld pool fluid dynamics, heat
A CONSISTENT MODELLING METHODOLOGY FOR SECONDARY1 SETTLING TANKS: A RELIABLE NUMERICAL METHOD2
Bürger, Raimund
relations for hindered settling, compression and dispersion can be used within the model, allowing the user, continuous sedimentation, secondary clarifier, simulation5 model, partial differential equation6 NomenclatureA CONSISTENT MODELLING METHODOLOGY FOR SECONDARY1 SETTLING TANKS: A RELIABLE NUMERICAL METHOD2
Numerical Experiments of Some Krylov Subspace Methods for Black Oil Model
Lai, Choi-Hong
Numerical Experiments of Some Krylov Subspace Methods for Black Oil Model Jianwen Cao #3; Choi of linear systems originated from the black oil model in oil reservoir simulation. There exists some Krylov subspace algorithms and pre- conditioning techniques for the black oil model as appeared in the literature
a uniformly accurate multiscale time integrator pseudospectral ...
2014-10-14T23:59:59.000Z
‡Beijing Computational Science Research Center, Beijing 100084, China; and Department of .... costs are significantly increased in the method in [10].
Numerical Zoom for Multiscale Problems with an Application to Nuclear Waste Disposal
Numerical Zoom for Multiscale Problems with an Application to Nuclear Waste Disposal Jean of a nuclear waste repository site. Key words: Multiscale, Finite Element, Domain Decomposition, Chimera, Numerical Zoom, Nuclear Waste. PACS: 02.30.Jr, 47.11.Fg, 28.41.Kw, 47.55.P- 1 Introduction The present paper
Ueckermann, Mattheus Percy
2009-01-01T23:59:59.000Z
A new generation of efficient parallel, multi-scale, and interdisciplinary ocean models is required for better understanding and accurate predictions. The purpose of this thesis is to quantitatively identify promising ...
Richardson, John G. (Idaho Falls, ID)
2009-11-17T23:59:59.000Z
An impedance estimation method includes measuring three or more impedances of an object having a periphery using three or more probes coupled to the periphery. The three or more impedance measurements are made at a first frequency. Three or more additional impedance measurements of the object are made using the three or more probes. The three or more additional impedance measurements are made at a second frequency different from the first frequency. An impedance of the object at a point within the periphery is estimated based on the impedance measurements and the additional impedance measurements.
Chen, H.W. (Los Alamos National Lab., NM (United States). Biophysics Group M715)
1995-01-01T23:59:59.000Z
Structural classification and parameter estimation (SCPE) methods are used for studying single-input single-output (SISO) parallel linear-nonlinear-linear (LNL), linear-nonlinear (LN), and nonlinear-linear (NL) system models from input-output (I-O) measurements. The uniqueness of the I-O mappings (see the definition of the I-O mapping in Section 3-A) of some model structures is discussed. The uniqueness of the I-O mappings (see the definition of the I-O mapping in Section 3-A) of some model structures is discussed. The uniqueness of I-O mappings of different models tells them in what conditions different model structures can be differentiated from one another. Parameter uniqueness of the I-O mapping of a given structural model is also discussed, which tells the authors in what conditions a given model's parameters can be uniquely estimated from I-O measurements. These methods are then generalized so that they can be used to study single-input multi-output (SIMO), multi-input single-output (MISO), as well as multi-input multi-output (MIMO) nonlinear system models. Parameter estimation of the two-input single-output nonlinear system model (denoted as the 2f-structure in 2 cited references), which was left unsolved previously, can now be obtained using the newly derived algorithms. Applications of SCPE methods for modeling visual cortical neurons, system fault detection, modeling and identification of communication networks, biological systems, and natural and artificial neural networks are also discussed. The feasibility of these methods is demonstrated using simulated examples. SCPE methods presented in this paper can be further developed to study more complicated block-structures models, and will therefore have future potential for modeling and identifying highly complex multi-input multi-output nonlinear systems.
Grunwald, Sabine
Comparison of multivariate methods for inferential modeling of soil carbon using visible Diffuse reflectance spectroscopy Visible/near-infrared spectroscopy Multivariate calibration Pre multivariate techniques (stepwise multiple linear regression, principal components regression, partial least
Modeling nighttime ecosystem respiration from measured CO2 concentration and air temperature ecosystem carbon budgets from micrometeorological methods remains nighttime ecosystem respiration theory to infer the two components of ecosystem respiration (aboveground and forest floor) from measured
Vega, Leonardo
1998-01-01T23:59:59.000Z
For a heterogeneous aquifer of unknown size and shape, ics. Aquifer Influence Functions (AIF) can be used to model the aquifer pressure behavior from field production and pressure data. Two methods have been used in the past to accomplish this...
Applying model-based methods to analyze genomics data Zhaohui Qin
Jin, Jiashun
Applying model-based methods to analyze genomics data by Zhaohui Qin Department of Biostatistics in the post-genomic era. Effective clustering and screening algorithms facilitate the identification of subtle
Sparse Models and Methods for Optimal Instruments with an Application to Eminent Domain
Belloni, Alexandre
2011-07-12T23:59:59.000Z
We develop results for the use of LASSO and Post-LASSO methods to form first-stage predictions and estimate optimal instruments in linear instrumental variables (IV) models with many instruments, p, that apply even when p ...
ENERGY Hydrogen Pipeline Material Testing Facility Objective We provide critical data, measurement methods and models that enable safe and economical transport, delivery and storage of hydrogen fuel predictions about the safe operating limits of pipelines carrying pressurized gaseous hydrogen, thereby
Lee, Sang Hoon
2012-02-14T23:59:59.000Z
, changing rock permeability. In this work, two- and three-dimensional finite element methods were developed to simulate coupled reservoirs with damage mechanics and stress-dependent permeability. The model considers the influence of fluid flow, temperature...
Model reduction for active control design using multiple-point Arnoldi methods
Lassaux, G.
A multiple-point Arnoldi method is derived for model reduction of computational fluid dynamic systems. By choosing the number of frequency interpolation points and the number of Arnoldi vectors at each frequency point, the ...
Lusk, Miriam Beatriz
2011-12-31T23:59:59.000Z
To capture the fracture process and non-linear behavior at the element and structural level of granular materials, concrete, under the presence of pre-existing imperfections, a constitutive model and a mesh free method is ...
Heinemann, Detlev
Solar energy applications Concentrated solar-thermal (CSP) Large grid-connected PV Remote area PVMotivation Methods Model configuration Results Forecasting Summary & Outlook 1/ 14 Retrieving Heinemann Institute of Physics, Energy Meteorology Group University of Oldenburg 1t
Zhang, Xuesong
2009-05-15T23:59:59.000Z
This study focuses on developing and evaluating efficient and effective parameter calibration and uncertainty methods for hydrologic modeling. Five single objective optimization algorithms and six multi-objective optimization ...
Griffith, Daniel Todd
2005-02-17T23:59:59.000Z
The main objective of this work is to demonstrate some new computational methods for estimation, optimization and modeling of dynamical systems that use automatic differentiation. Particular focus will be upon dynamical ...
Ray methods in the modelling of seismic wave fields Ivan Psenc'ik
Cerveny, Vlastislav
and in the solution of forward and inverse problems of seismology and seismic exploration for oil. This contributionRay methods in the modelling of seismic wave fields Ivan PĹ¸senĹ¸c'ik Academy of Sciences, BoĹ¸cn'i II@seis.karlov.mff.cuni.cz Abstract Seismic ray method has broad applications in the numerical modelling of seismic wave fields
Ringler, Todd D [Los Alamos National Laboratory; Gunzburger, Max [FLORIDA STATE UNIV; Ju, Lili [UNIV OF SOUTH CAROLINA
2008-01-01T23:59:59.000Z
During the next decade and beyond, climate system models will be challenged to resolve scales and processes that are far beyond their current scope. Each climate system component has its prototypical example of an unresolved process that may strongly influence the global climate system, ranging from eddy activity within ocean models, to ice streams within ice sheet models, to surface hydrological processes within land system models, to cloud processes within atmosphere models. These new demands will almost certainly result in the develop of multi-resolution schemes that are able, at least regional to faithfully simulate these fine-scale processes. Spherical Centroidal Voronoi Tessellations (SCVTs) offer one potential path toward the development of robust, multi-resolution climate system component models, SCVTs allow for the generation of high quality Voronoi diagrams and Delaunay triangulations through the use of an intuitive, user-defined density function, each of the examples provided, this method results in high-quality meshes where the quality measures are guaranteed to improve as the number of nodes is increased. Real-world examples are developed for the Greenland ice sheet and the North Atlantic ocean. Idealized examples are developed for ocean-ice shelf interaction and for regional atmospheric modeling. In addition to defining, developing and exhibiting SCVTs, we pair this mesh generation technique with a previously developed finite-volume method. Our numerical example is based on the nonlinear shallow-water equations spanning the entire surface of the sphere. This example is used to elucidate both the potential benefits of this multi-resolution method and the challenges ahead.
Sereda, Yuriy V.; Ortoleva, Peter J., E-mail: ortoleva@indiana.edu [Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405 (United States)
2014-04-07T23:59:59.000Z
A closed kinetic equation for the single-particle density of a viscous simple liquid is derived using a variational method for the Liouville equation and a coarse-grained mean-field (CGMF) ansatz. The CGMF ansatz is based on the notion that during the characteristic time of deformation a given particle interacts with many others so that it experiences an average interaction. A trial function for the N-particle probability density is constructed using a multiscale perturbation method and the CGMF ansatz is applied to it. The multiscale perturbation scheme is based on the ratio of the average nearest-neighbor atom distance to the total size of the assembly. A constraint on the initial condition is discovered which guarantees that the kinetic equation is mass-conserving and closed in the single-particle density. The kinetic equation has much of the character of the Vlasov equation except that true viscous, and not Landau, damping is accounted for. The theory captures condensation kinetics and takes much of the character of the Gross-Pitaevskii equation in the weak-gradient short-range force limit.
Mixed-RKDG Finite Element Methods for the 2-D Hydrodynamic Model for Semiconductor Device Simulation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Chen, Zhangxin; Cockburn, Bernardo; Jerome, Joseph W.; Shu, Chi-Wang
1995-01-01T23:59:59.000Z
In this paper we introduce a new method for numerically solving the equations of the hydrodynamic model for semiconductor devices in two space dimensions. The method combines a standard mixed finite element method, used to obtain directly an approximation to the electric field, with the so-called Runge-Kutta Discontinuous Galerkin (RKDG) method, originally devised for numerically solving multi-dimensional hyperbolic systems of conservation laws, which is applied here to the convective part of the equations. Numerical simulations showing the performance of the new method are displayed, and the results compared with those obtained by using Essentially Nonoscillatory (ENO) finite difference schemes. Frommore »the perspective of device modeling, these methods are robust, since they are capable of encompassing broad parameter ranges, including those for which shock formation is possible. The simulations presented here are for Gallium Arsenide at room temperature, but we have tested them much more generally with considerable success.« less
Modeling and estimation in Gaussian graphical models : maximum-entropy methods and walk-sum analysis
Chandrasekaran, Venkat
2007-01-01T23:59:59.000Z
Graphical models provide a powerful formalism for statistical signal processing. Due to their sophisticated modeling capabilities, they have found applications in a variety of fields such as computer vision, image processing, ...
Sensitivity of Ocean-Atmosphere Coupled Models to the Coupling Method : Example of Tropical Cyclone
that the iterative process of the method ensures consistency of the coupled solution across the air-sea interface infrastructure, and a coupling algorithm. Sev- eral parameterizations for surface atmospheric flow dynamics underSensitivity of Ocean-Atmosphere Coupled Models to the Coupling Method : Example of Tropical Cyclone
Furumura, Takashi
coordinates using the pseudospectral method (PSM). The PSM is an attractive time- domain technique that uses the heterogeneity in the model. Synthetic seismograms obtained by the PSM calculation are compared with those agreement. The PSM method is illustrated by constructing the seismic P^SV wave˘eld for strongly
A quick and efficient method for consistent initialization of battery models
Subramanian, Venkat
criterion on the other end that can ulti- mately satisfy all the required conditions in a battery unitA quick and efficient method for consistent initialization of battery models Vijayasekaran 2007 Available online 21 April 2007 Abstract Secondary batteries are usually modeled as a system
Statistical prediction of aircraft trajectory: regression methods vs point-mass model
Paris-Sud XI, Université de
the altitude of climbing aircraft. In addition to the standard linear regression model, two common non-linear, BADA, linear regression, neural networks, Loess. INTRODUCTION Predicting aircraft trajectoriesStatistical prediction of aircraft trajectory: regression methods vs point-mass model M. Ghasemi
Incident and in situ irradiance in Lakes Cadagno and Lucerne: A comparison of methods and models
Sommaruga, Ruben
Incident and in situ irradiance in Lakes Cadagno and Lucerne: A comparison of methods and models Key words: Lake Lucerne, Lake Cadagno, PAR, UV-A, UV-B, irradiance regime, radiative transfer models) at the field stations Kastanienbaum at Lake Lucerne (434 m a.s.l.) and Piora at Lake Cadagno (1923 m a
Conditional modeling and the jitter method of spike resampling Asohan Amarasingham,1
Hatsopoulos, Nicholas
Review Conditional modeling and the jitter method of spike resampling Asohan Amarasingham,1 October 2011 Amarasingham A, Harrison MT, Hatsopoulos NG, Geman S. Conditional modeling and the jitter correct hypoth- esis tests. We focus on the approach to resampling known as jitter. We review a wide range
A consistent modelling methodology for secondary settling tanks: a reliable numerical method
Bürger, Raimund
accounting for sediment compressibility, and a dispersion term for turbulence. In addition, the solutionA consistent modelling methodology for secondary settling tanks: a reliable numerical method modelling methodology for secondary settling tanks (SSTs) leads to a partial differential equation (PDE
Supersonic combustion studies using a multivariate quadrature based method for combustion modeling
Raman, Venkat
Supersonic combustion studies using a multivariate quadrature based method for combustion modeling function (PDF) of thermochemical variables can be used for accurately computing the combustion source term of predictive models for supersonic combustion is a critical step in design and development of scramjet engines
Bayesian methods for the quantification of uncertainties in syngas chemistry models
Raman, Venkat
Bayesian methods for the quantification of uncertainties in syngas chemistry models Kalen Braman, Todd Oliver and Venkat Raman, The University of Texas, Austin, Texas, 78712 Syngas chemistry modeling is an integral step toward the development of safe and ef- ficient syngas combustors. Although substantial effort
Modeling Respiratory Lung Motion a Biophysical Approach using Finite Element Methods
Lübeck, Universität zu
Modeling Respiratory Lung Motion a Biophysical Approach using Finite Element Methods Rene Wernera motion gains in importance. In this paper a biophysical approach for modeling lung motion is described. Main aspects of the process of lung ventilation are identified and outlined as the starting point
Bangerth, Wolfgang
Adaptive finite element methods for forward modeling in fluorescence enhanced frequency domain for Subsurface Modeling, ICES, University of Texas, Austin, TX Abstract: An adaptive finite element scheme the boundary measurements of photon energy resulting from the tissue stimulation via infrared light sources
Research on a Model of Extracting Persons' Information Based on Statistic Method
Research on a Model of Extracting Persons' Information Based on Statistic Method and Conceptual Abstract. In order to extract some important information of a person from text, an extracting model base. The three main elements of events, domain, situation and background, are also extracted from
Approximation Methods for Pricing Problems under the Nested Logit Model with Price Bounds
Rusmevichientong, Paat
Approximation Methods for Pricing Problems under the Nested Logit Model with Price Bounds W@orie.cornell.edu September 5, 2013 Abstract We consider two variants of a pricing problem under the nested logit model. In the first variant, the set of products offered to customers is fixed and we want to determine the prices
Gracie, Robert
PeerReview Only An XFEM Model for Carbon Sequestration Journal: International Journal for Numerical method, Carbon Sequestration, Multiphase flow, XFEM, Multifield systems, Petrov-Galerkin httpScience (www.interscience.wiley.com). DOI: 10.1002/nme An XFEM Model for Carbon Sequestration Chris Ladubec
Physics-based statistical model and simulation method of RF propagation in urban environments
Pao, Hsueh-Yuan (San Jose, CA); Dvorak, Steven L. (Tucson, AZ)
2010-09-14T23:59:59.000Z
A physics-based statistical model and simulation/modeling method and system of electromagnetic wave propagation (wireless communication) in urban environments. In particular, the model is a computationally efficient close-formed parametric model of RF propagation in an urban environment which is extracted from a physics-based statistical wireless channel simulation method and system. The simulation divides the complex urban environment into a network of interconnected urban canyon waveguides which can be analyzed individually; calculates spectral coefficients of modal fields in the waveguides excited by the propagation using a database of statistical impedance boundary conditions which incorporates the complexity of building walls in the propagation model; determines statistical parameters of the calculated modal fields; and determines a parametric propagation model based on the statistical parameters of the calculated modal fields from which predictions of communications capability may be made.
HMMSeg wavelet methods Robert E. Thurman
Noble, William Stafford
HMMSeg wavelet methods Robert E. Thurman Division of Medical Genetics Department of Genome Sciences University of Washington February 5, 2007 Wavelets provide a framework for multi-scale analysis. By decomposing a given data type into increasingly coarser scales, wavelet analysis allows broader and broader
Multiscale CFD simulations of entrained flow gasification
Kumar, Mayank, Ph. D. Massachusetts Institute of Technology
2011-01-01T23:59:59.000Z
The design of entrained flow gasifiers and their operation has largely been an experience based enterprise. Most, if not all, industrial scale gasifiers were designed before it was practical to apply CFD models. Moreover, ...
Multiscale modeling of damage in multidirectional composite laminates
Singh, Chandra Veer
2009-05-15T23:59:59.000Z
the strengths of micro-damage mechanics (MDM) and continuum damage mechanics (CDM) in predicting the sti - ness degradation due to these cracks. The micromechanics is performed on a repre- sentative unit cell using a three-dimensional nite element analysis.... Results and Discussion . . . . . . . . . . . . . . . . . . . . 83 1. Crack Surface Displacements . . . . . . . . . . . . . . 83 2. Prediction of Sti ness Degradation . . . . . . . . . . . 89 3. Parametric Study of Constraint E ects . . . . . . . . 91 4...
Kinetic Theories in Multiscale Modeling of Polycrystals Maria Emelianenko
Maryland at College Park, University of
Metallkunde, 96 (2005) 207. Recent discovery Grain boundary character (GBCD) is a scale invariant steady state
Optimization Online - A stochastic multiscale model for electricity ...
Panos Parpas
2011-05-30T23:59:59.000Z
May 30, 2011 ... However, current trends such as increasing penetration of intermittent renewable generation and increased demand response requires a ...
Multiscale Modeling and Simulation of Fluid Flows in Inelastic Media
Popov, Peter
in porous media (e.g. soil), Elasticity equations in heterogeneous media (concrete, asphalt), etc permeability K = 0.0045 0.0000 0.0000 0.0000 0.0025 0.0000 0.0000 0.0000 0.0043 #12;- p. 8/42 Nonlinear
An improved multiscale model for dilute turbulent gas particle...
Office of Scientific and Technical Information (OSTI)
applications, such as the scale-up in the design of circulating fluidized combustor and coal gasifications. In engineering applications, the particle volume fraction can vary from...
Multiscale modeling and analysis of nanofibers and nonwoven materials
Buell, Sezen
2010-01-01T23:59:59.000Z
Nanostructured fibrous materials have been made more readily available in large part owing to recent advances in electrospinning, which is a technique for the production of nanofibers with diameters down to the range of a ...
Multiscale Modeling, Simulation and Control of Protein Crystallization Processes
Nayhouse, Michael Jeffrey
2015-01-01T23:59:59.000Z
Stochastic simulation of chemical kinetics. Annu. Rev. Phys.in protein crystal growth. Chemical Engineering Science, 87:time evolution of coupled chemical reactions. J. Comput.
Multiscale Modeling of Process Dynamics and Microstructure Development...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of Process Dynamics and Microstructure Development in Laser-based Keyhole Welding and Additive Manufacturing Jun 05 2015 10:00 AM - 11:00 AM Wenda Tan, University of Utah, Salt...
Multi-Scale Indentation Hardness Testing; A Correlation and Model
Bennett, Damon W.
2010-01-20T23:59:59.000Z
d Indentation diagonal PA Projected cross-sectional contact area SA Actual contact surface area g Gravitational acceleration ITH Indentation hardness mp Mean contact pressure C Constraint factor E Elastic modulus of the sample /E Elastic... result, it is used in corrosive environments such as oil and gas pipelines. Other pertinent properties for tantalum are discussed below. Tantalum is classified as a refractory metal (heat resistant metals with melting temperatures over 3000?F (1650?C...
Multiscale modeling of damage in multidirectional composite laminates
Singh, Chandra Veer
2009-05-15T23:59:59.000Z
provides reasonable predictions for multidirectional laminatesin which intralaminar cracks may form in multiple orientations. Nevertheless, theprediction of damage accumulation and its effect on structural performance is a verydifficult problem due...
Multiscale Computational Modeling of Multiphase Composites with Damage
Cheng, Feifei
2013-11-01T23:59:59.000Z
and interfacial layer with low effective thermal conductivity lowers the overall heat flux flowing through NiTi/Ti_(3)SiC_(2) IPC. The existence of thermal residual stress within stainless-steel/bronze IPCs leads to plastic deformation, especially in bronze...
Sketch interpretation using multiscale stochastic models of temporal patterns
Sezgin, Tevfik Metin, 1978-
2006-01-01T23:59:59.000Z
Sketching is a natural mode of interaction used in a variety of settings. For example, people sketch during early design and brainstorming sessions to guide the thought process; when we communicate certain ideas, we use ...
Multiscale computational models of transmural heterogeneities and ventricular arrhythmogenesis
Flaim, Sarah N.
2006-01-01T23:59:59.000Z
G, Keating MT, Towbin JA, Beggs AH, Brink P, Wilde AAM,G, Keating MT, Towbin JA, Beggs AH, Brink P, Wilde AA,G, Keating MT, Towbin JA, Beggs AH, Brink P, Wilde AA,
Gardner, Shea Nicole (San Leandro, CA)
2007-10-23T23:59:59.000Z
A method and system for tailoring treatment regimens to individual patients with diseased cells exhibiting evolution of resistance to such treatments. A mathematical model is provided which models rates of population change of proliferating and quiescent diseased cells using cell kinetics and evolution of resistance of the diseased cells, and pharmacokinetic and pharmacodynamic models. Cell kinetic parameters are obtained from an individual patient and applied to the mathematical model to solve for a plurality of treatment regimens, each having a quantitative efficacy value associated therewith. A treatment regimen may then be selected from the plurlaity of treatment options based on the efficacy value.
G. J. de Frias; W. Aquino; K. H. Pierson; M. W. Heinstein; B. W. Spencer
2014-03-01T23:59:59.000Z
One of the main computational issues with explicit dynamics simulations is the significant reduction of the critical time step as the spatial resolution of the finite element mesh increases. In this work, a selective mass scaling approach is presented that can significantly reduce the computational cost in explicit dynamic simulations, while maintaining accuracy. The proposed method is based on a multiscale decomposition approach that separates the dynamics of the system into low (coarse scales) and high frequencies (fine scales). Here, the critical time step is increased by selectively applying mass scaling on the fine scale component only. In problems where the response is dominated by the coarse (low frequency) scales, significant increases in the stable time step can be realized. In this work, we use the proper orthogonal decomposition (POD) method to build the coarse scale space. The main idea behind POD is to obtain an optimal low-dimensional orthogonal basis for representing an ensemble of high-dimensional data. In our proposed method, the POD space is generated with snapshots of the solution obtained from early times of the full-scale simulation. The example problems addressed in this work show significant improvements in computational time, without heavily compromising the accuracy of the results.
A method for the quantification of model form error associated with physical systems.
Wallen, Samuel P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brake, Matthew Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2014-03-01T23:59:59.000Z
In the process of model validation, models are often declared valid when the differences between model predictions and experimental data sets are satisfactorily small. However, little consideration is given to the effectiveness of a model using parameters that deviate slightly from those that were fitted to data, such as a higher load level. Furthermore, few means exist to compare and choose between two or more models that reproduce data equally well. These issues can be addressed by analyzing model form error, which is the error associated with the differences between the physical phenomena captured by models and that of the real system. This report presents a new quantitative method for model form error analysis and applies it to data taken from experiments on tape joint bending vibrations. Two models for the tape joint system are compared, and suggestions for future improvements to the method are given. As the available data set is too small to draw any statistical conclusions, the focus of this paper is the development of a methodology that can be applied to general problems.
Implementation of the Immersed Boundary Method in the Weather Research and Forecasting model
Lundquist, K A
2006-12-07T23:59:59.000Z
Accurate simulations of atmospheric boundary layer flow are vital for predicting dispersion of contaminant releases, particularly in densely populated urban regions where first responders must react within minutes and the consequences of forecast errors are potentially disastrous. Current mesoscale models do not account for urban effects, and conversely urban scale models do not account for mesoscale weather features or atmospheric physics. The ultimate goal of this research is to develop and implement an immersed boundary method (IBM) along with a surface roughness parameterization into the mesoscale Weather Research and Forecasting (WRF) model. IBM will be used in WRF to represent the complex boundary conditions imposed by urban landscapes, while still including forcing from regional weather patterns and atmospheric physics. This document details preliminary results of this research, including the details of three distinct implementations of the immersed boundary method. Results for the three methods are presented for the case of a rotation influenced neutral atmospheric boundary layer over flat terrain.
MULTISCALE FLOW AND TRANSPORT IN POROUS MEDIA
governed by stochastic nonlinear coupled systems of partial di erential equations ... This represents a formidable ... of two-phase ow in oil reservoirs, presents a class .... (2..5). The mean of x(!; t) is then approximated by. hx(!; t)i. 1. X. n=0. (i ) n. n! ..... Figure 4.1 shows a gray scale plot of a real- .... ow I: Single porosity models.
Dorland, William [University of Maryland
2014-11-18T23:59:59.000Z
The Center for Multiscale Plasma Dynamics (CMPD) was a five-year Fusion Science Center. The University of Maryland (UMD) and UCLA were the host universities. This final technical report describes the physics results from the UMD CMPD.
Garnier, Josselin
multiscale analysis the hotspot dynamics during the deceleration phase of inertial confinement December 2004) paper is devoted study deceleration phase inertial confinement capsules. First self. [DOI: 10.1063/1.1825389] INTRODUCTION dynamics the deceleration phase inertial con finement fusion
Multiscale Physical and Biological Dynamics in the Philippine Archipelago: Predictions and Processes
Lermusiaux, Pierre F. J.
The Philippine Archipelago is remarkable because of its complex geometry, with multiple islands and passages, and its multiscale dynamics, from the large-scale open-ocean and atmospheric forcing, to the strong tides and ...
Park, Han-Young
2012-10-19T23:59:59.000Z
field-level energy (pressure), which is followed by local update where we match well-by-well performances by calibration of local cell properties. The inclusion of multiscale calibration, integrating production data in coarse grid and successively finer...
Bootstrap multiscale analysis and localization for multi-particle continuous Anderson Hamiltonians
Abel Klein; Son Nguyen
2014-04-15T23:59:59.000Z
We extend the bootstrap multiscale analysis developed by Germinet and Klein to the multi-particle continuous Anderson Hamiltonian, obtaining Anderson localization with finite multiplicity of eigenvalues, decay of eigenfunction correlations, and a strong form of dynamical localization.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gan, Yanjun; Duan, Qingyun; Gong, Wei; Tong, Charles; Sun, Yunwei; Chu, Wei; Ye, Aizhong; Miao, Chiyuan; Di, Zhenhua
2014-01-01T23:59:59.000Z
Sensitivity analysis (SA) is a commonly used approach for identifying important parameters that dominate model behaviors. We use a newly developed software package, a Problem Solving environment for Uncertainty Analysis and Design Exploration (PSUADE), to evaluate the effectiveness and efficiency of ten widely used SA methods, including seven qualitative and three quantitative ones. All SA methods are tested using a variety of sampling techniques to screen out the most sensitive (i.e., important) parameters from the insensitive ones. The Sacramento Soil Moisture Accounting (SAC-SMA) model, which has thirteen tunable parameters, is used for illustration. The South Branch Potomac River basin nearmore »Springfield, West Virginia in the U.S. is chosen as the study area. The key findings from this study are: (1) For qualitative SA methods, Correlation Analysis (CA), Regression Analysis (RA), and Gaussian Process (GP) screening methods are shown to be not effective in this example. Morris One-At-a-Time (MOAT) screening is the most efficient, needing only 280 samples to identify the most important parameters, but it is the least robust method. Multivariate Adaptive Regression Splines (MARS), Delta Test (DT) and Sum-Of-Trees (SOT) screening methods need about 400–600 samples for the same purpose. Monte Carlo (MC), Orthogonal Array (OA) and Orthogonal Array based Latin Hypercube (OALH) are appropriate sampling techniques for them; (2) For quantitative SA methods, at least 2777 samples are needed for Fourier Amplitude Sensitivity Test (FAST) to identity parameter main effect. McKay method needs about 360 samples to evaluate the main effect, more than 1000 samples to assess the two-way interaction effect. OALH and LP? (LPTAU) sampling techniques are more appropriate for McKay method. For the Sobol' method, the minimum samples needed are 1050 to compute the first-order and total sensitivity indices correctly. These comparisons show that qualitative SA methods are more efficient but less accurate and robust than quantitative ones.« less
Multiscale schemes for the predictive description and virtual engineering of materials.
von Lilienfeld-Toal, Otto Anatole
2010-09-01T23:59:59.000Z
This report documents research carried out by the author throughout his 3-years Truman fellowship. The overarching goal consisted of developing multiscale schemes which permit not only the predictive description but also the computational design of improved materials. Identifying new materials through changes in atomic composition and configuration requires the use of versatile first principles methods, such as density functional theory (DFT). Using DFT, its predictive reliability has been investigated with respect to pseudopotential construction, band-gap, van-der-Waals forces, and nuclear quantum effects. Continuous variation of chemical composition and derivation of accurate energy gradients in compound space has been developed within a DFT framework for free energies of solvation, reaction energetics, and frontier orbital eigenvalues. Similar variations have been leveraged within classical molecular dynamics in order to address thermal properties of molten salt candidates for heat transfer fluids used in solar thermal power facilities. Finally, a combination of DFT and statistical methods has been used to devise quantitative structure property relationships for the rapid prediction of charge mobilities in polyaromatic hydrocarbons.
Tian, Zhiting
Knowledge on phonon transmittance as a function of phonon frequency and incidence angle at interfaces is vital for multiscale modeling of heat transport in nanostructured materials. Although thermal conductivity reduction ...
Hwang, Yu-Jer
2012-01-01T23:59:59.000Z
as a substrate material. Experimental Section Supramolecularmaterials: multi-scale and multi-modality characterization Abstract .5 Introduction 6 Experimental Section Supramolecular
Lek, Sovan
, Greece Abstract Convinced by the predictive quality of artificial neural network (ANN) models in ecology. # 2002 Published by Elsevier Science B.V. Keywords: Artificial neural networks; Backpropagation; NonReview and comparison of methods to study the contribution of variables in artificial neural
Numerical methods for the simulation of a corrosion model in a nuclear waste deep repository $
Paris-Sud XI, Université de
Numerical methods for the simulation of a corrosion model in a nuclear waste deep repository $ C of the French nuclear waste management agency ANDRA, investigations are conducted to optimize and finalize by the Nuclear Waste Management Agency ANDRA Corresponding author. Phone: +49 30 20372 560, Fax: +49 30 2044975
Novel Method for Incorporating Model Uncertainties into Gravitational Wave Parameter Estimates
Christopher J. Moore; Jonathan R. Gair
2014-12-11T23:59:59.000Z
Posterior distributions on parameters computed from experimental data using Bayesian techniques are only as accurate as the models used to construct them. In many applications these models are incomplete, which both reduces the prospects of detection and leads to a systematic error in the parameter estimates. In the analysis of data from gravitational wave detectors, for example, accurate waveform templates can be computed using numerical methods, but the prohibitive cost of these simulations means this can only be done for a small handful of parameters. In this work a novel method to fold model uncertainties into data analysis is proposed; the waveform uncertainty is analytically marginalised over using with a prior distribution constructed by using Gaussian process regression to interpolate the waveform difference from a small training set of accurate templates. The method is well motivated, easy to implement, and no more computationally expensive than standard techniques. The new method is shown to perform extremely well when applied to a toy problem. While we use the application to gravitational wave data analysis to motivate and illustrate the technique, it can be applied in any context where model uncertainties exist.
B. Julia-Diaz; H. Kamano; T. -S. H. Lee; A. Matsuyama; T. Sato; N. Suzuki
2009-02-18T23:59:59.000Z
Within the relativistic quantum field theory, we analyze the differences between the $\\pi N$ reaction models constructed from using (1) three-dimensional reductions of Bethe-Salpeter Equation, (2) method of unitary transformation, and (3) time-ordered perturbation theory. Their relations with the approach based on the dispersion relations of S-matrix theory are dicusssed.
FSR Methods for Second-Order Regression Models Hugh B. Crews
Boos, Dennis
approach to forward selection by using different -to-enter values for first-order and second-order terms-order linear regression models. Often, interaction and quadratic terms are also of interest, but the number-order terms. Method performance is compared through Monte Carlo simulation, and an illustration is provided
FSR Methods for Second-Order Regression Models Hugh B. Crews1
Boos, Dennis
-order linear regression models. Often, interaction and quadratic terms are also of interest, but the number first-order and second-order terms. Method performance is compared through Monte Carlo simulation optimization, selecting interaction and quadratic terms is important. In such applications, second-order terms
Robust model based control method for wind energy production A. Pintea 1
Boyer, Edmond
Robust model based control method for wind energy production A. Pintea 1 , D. Popescu 1 , Ioana system. Keywords: Wind power, robustness, IMC, stability, turbine, pitch control. 1. INTRODUCTION Wind energy has proved to be an important source of clean and renewable energy because no fossil fuels
A New Method for Modeling and Solving the Protein Fold Recognition Problem
Istrail, Sorin
Idstract A New Method for Modeling and Solving the Protein Fold Recognition Problem (Extended}@ornl.gov Computational recognition of native-like folds from a protein fold database is considered to be a promising recog- nition through optimally aligning (threading) an amino acid sequence and a protein fold (template
Liu, Yijun
A fast multipole boundary element method for modeling 2-D multiple crack problems with constant 3 April 2014 Accepted 20 May 2014 Keywords: Fast multipole BEM 2-D multi-crack problems Constant elements Crack opening displacements Stress intensity factors a b s t r a c t A fast multipole boundary
FINITE WAVELET DOMAIN METHOD FOR EFFICIENT MODELING OF LAMB WAVE BASED STRUCTURAL HEALTH MONITORING
Paris-Sud XI, Université de
FINITE WAVELET DOMAIN METHOD FOR EFFICIENT MODELING OF LAMB WAVE BASED STRUCTURAL HEALTH MONITORING element exploits the advantages of wavelets for the spatial discretization of the displacement field : Wavelet-based Finite Element, Transient Response. 1 INTRODUCTION The dynamic transient response and wave
Modeling Plasma Flow in a Magnetic Nozzle with the Lattice-Boltzmann Method
Ebersohn, Frans Hendrik
2010-07-14T23:59:59.000Z
run by NASA. The code was shown to predict accurately the physics of the experiment. Another study [20] conducted research with both computational and experimental studies. From their experimental studies they gained a variety radial... equation??..?..?..21 Plasma physics?????????????????.?24 Kinetic plasma theory and magnetohydrodynamics??..?..27 Plasma detachment mechanics??????????.....?31 IV COMPUTATIONAL MODEL????????????????.35 Lattice Boltzmann method...
Mills, Richard
Evaluating variable switching and flash methods in modeling carbon sequestration in deep geologic performance computing to assess the risks involved in carbon sequestration in deep geologic formations-thermal- chemical processes in variably saturated, non-isothermal porous media is applied to sequestration
Abundance determinations in HII regions: model fitting versus Te-method
L. S. Pilyugin
2002-11-14T23:59:59.000Z
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.
Ewing, Richard E.
, where the fluid (oil, water, gas) meets no resistance form the surrounding rock [1]. The main difficulty
Control method and system for hydraulic machines employing a dynamic joint motion model
Danko, George (Reno, NV)
2011-11-22T23:59:59.000Z
A control method and system for controlling a hydraulically actuated mechanical arm to perform a task, the mechanical arm optionally being a hydraulically actuated excavator arm. The method can include determining a dynamic model of the motion of the hydraulic arm for each hydraulic arm link by relating the input signal vector for each respective link to the output signal vector for the same link. Also the method can include determining an error signal for each link as the weighted sum of the differences between a measured position and a reference position and between the time derivatives of the measured position and the time derivatives of the reference position for each respective link. The weights used in the determination of the error signal can be determined from the constant coefficients of the dynamic model. The error signal can be applied in a closed negative feedback control loop to diminish or eliminate the error signal for each respective link.
geological model by any method requires much analysis and redefinition and is not a fast or simple process. The process of building a geological model is an iterative one. First, the geoscientist builds required to construct a three dimensional model of geology. There are many computational methods
Multiscale polar theory of microtubule and motor-protein assemblies
Tong Gao; Robert Blackwell; Matthew A. Glaser; M. D. Betterton; Michael J. Shelley
2015-01-27T23:59:59.000Z
Microtubules and motor proteins are building blocks of self-organized subcellular biological structures such as the mitotic spindle and the centrosomal microtubule array. These same ingredients can form new "bioactive" liquid-crystalline fluids that are intrinsically out of equilibrium and which display complex flows and defect dynamics. It is not yet well understood how microscopic activity, which involves polarity-dependent interactions between motor proteins and microtubules, yields such larger scale dynamical structures. In our multiscale theory, Brownian dynamics simulations of polar microtubule ensembles driven by crosslinking motors allow us to study microscopic organization and stresses. Polarity sorting and crosslink relaxation emerge as two polar-specific sources of active destabilizing stress. On larger length scales, our continuum Doi-Onsager theory captures the hydrodynamic flows generated by polarity-dependent active stresses. The results connect local polar structure to flow structures and defect dynamics.
High-order continuum kinetic method for modeling plasma dynamics in phase space
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Vogman, G. V.; Colella, P.; Shumlak, U.
2014-12-15T23:59:59.000Z
Continuum methods offer a high-fidelity means of simulating plasma kinetics. While computationally intensive, these methods are advantageous because they can be cast in conservation-law form, are not susceptible to noise, and can be implemented using high-order numerical methods. Advances in continuum method capabilities for modeling kinetic phenomena in plasmas require the development of validation tools in higher dimensional phase space and an ability to handle non-cartesian geometries. To that end, a new benchmark for validating Vlasov-Poisson simulations in 3D (x,vx,vy) is presented. The benchmark is based on the Dory-Guest-Harris instability and is successfully used to validate a continuum finite volumemore »algorithm. To address challenges associated with non-cartesian geometries, unique features of cylindrical phase space coordinates are described. Preliminary results of continuum kinetic simulations in 4D (r,z,vr,vz) phase space are presented.« less
Wan, Hui; Rasch, Philip J.; Zhang, Kai; Qian, Yun; Yan, Huiping; Zhao, Chun
2014-09-08T23:59:59.000Z
This paper explores the feasibility of an experimentation strategy for investigating sensitivities in fast components of atmospheric general circulation models. The basic idea is to replace the traditional serial-in-time long-term climate integrations by representative ensembles of shorter simulations. The key advantage of the proposed method lies in its efficiency: since fewer days of simulation are needed, the computational cost is less, and because individual realizations are independent and can be integrated simultaneously, the new dimension of parallelism can dramatically reduce the turnaround time in benchmark tests, sensitivities studies, and model tuning exercises. The strategy is not appropriate for exploring sensitivity of all model features, but it is very effective in many situations. Two examples are presented using the Community Atmosphere Model version 5. The first example demonstrates that the method is capable of characterizing the model cloud and precipitation sensitivity to time step length. A nudging technique is also applied to an additional set of simulations to help understand the contribution of physics-dynamics interaction to the detected time step sensitivity. In the second example, multiple empirical parameters related to cloud microphysics and aerosol lifecycle are perturbed simultaneously in order to explore which parameters have the largest impact on the simulated global mean top-of-atmosphere radiation balance. Results show that in both examples, short ensembles are able to correctly reproduce the main signals of model sensitivities revealed by traditional long-term climate simulations for fast processes in the climate system. The efficiency of the ensemble method makes it particularly useful for the development of high-resolution, costly and complex climate models.
Ringler, Todd [Los Alamos National Laboratory; Ju, Lili [University of South Carolina; Gunzburger, Max [Florida State University
2008-01-01T23:59:59.000Z
During the next decade and beyond, climate system models will be challenged to resolve scales and processes that are far beyond their current scope. Each climate system component has its prototypical example of an unresolved process that may strongly influence the global climate system, ranging from eddy activity within ocean models, to ice streams within ice sheet models, to surface hydrological processes within land system models, to cloud processes within atmosphere models. These new demands will almost certainly result in the develop of multiresolution schemes that are able, at least regionally, to faithfully simulate these fine-scale processes. Spherical centroidal Voronoi tessellations (SCVTs) offer one potential path toward the development of a robust, multiresolution climate system model components. SCVTs allow for the generation of high quality Voronoi diagrams and Delaunay triangulations through the use of an intuitive, user-defined density function. In each of the examples provided, this method results in high-quality meshes where the quality measures are guaranteed to improve as the number of nodes is increased. Real-world examples are developed for the Greenland ice sheet and the North Atlantic ocean. Idealized examples are developed for ocean–ice shelf interaction and for regional atmospheric modeling. In addition to defining, developing, and exhibiting SCVTs, we pair this mesh generation technique with a previously developed finite-volume method. Our numerical example is based on the nonlinear, shallow water equations spanning the entire surface of the sphere. This example is used to elucidate both the potential benefits of this multiresolution method and the challenges ahead.
Anderson, R W; Pember, R B; Elliot, N S
2000-09-26T23:59:59.000Z
A new method for the solution of the unsteady Euler equations has been developed. The method combines staggered grid Lagrangian techniques with structured local adaptive mesh refinement (AMR). This method is a precursor to a more general adaptive arbitrary Lagrangian Eulerian (ALE-AMR) algorithm under development, which will facilitate the solution of problems currently at and beyond the boundary of soluble problems by traditional ALE methods by focusing computational resources where they are required. Many of the core issues involved in the development of the ALE-AMR method hinge upon the integration of AMR with a Lagrange step, which is the focus of the work described here. The novel components of the method are mainly driven by the need to reconcile traditional AMR techniques, which are typically employed on stationary meshes with cell-centered quantities, with the staggered grids and grid motion employed by Lagrangian methods. These new algorithmic components are first developed in one dimension and are then generalized to two dimensions. Solutions of several model problems involving shock hydrodynamics are presented and discussed.
Model reduction for slow–fast stochastic systems with metastable behaviour
Bruna, Maria, E-mail: bruna@maths.ox.ac.uk [Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom) [Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom); Computational Science Laboratory, Microsoft Research, Cambridge CB1 2FB (United Kingdom); Chapman, S. Jonathan [Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom)] [Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom); Smith, Matthew J. [Computational Science Laboratory, Microsoft Research, Cambridge CB1 2FB (United Kingdom)] [Computational Science Laboratory, Microsoft Research, Cambridge CB1 2FB (United Kingdom)
2014-05-07T23:59:59.000Z
The quasi-steady-state approximation (or stochastic averaging principle) is a useful tool in the study of multiscale stochastic systems, giving a practical method by which to reduce the number of degrees of freedom in a model. The method is extended here to slow–fast systems in which the fast variables exhibit metastable behaviour. The key parameter that determines the form of the reduced model is the ratio of the timescale for the switching of the fast variables between metastable states to the timescale for the evolution of the slow variables. The method is illustrated with two examples: one from biochemistry (a fast-species-mediated chemical switch coupled to a slower varying species), and one from ecology (a predator–prey system). Numerical simulations of each model reduction are compared with those of the full system.
Wang, Shaobu; Lu, Shuai; Zhou, Ning; Lin, Guang; Elizondo, Marcelo A.; Pai, M. A.
2014-09-04T23:59:59.000Z
In interconnected power systems, dynamic model reduction can be applied on generators outside the area of interest to mitigate the computational cost with transient stability studies. This paper presents an approach of deriving the reduced dynamic model of the external area based on dynamic response measurements, which comprises of three steps, dynamic-feature extraction, attribution and reconstruction (DEAR). In the DEAR approach, a feature extraction technique, such as singular value decomposition (SVD), is applied to the measured generator dynamics after a disturbance. Characteristic generators are then identified in the feature attribution step for matching the extracted dynamic features with the highest similarity, forming a suboptimal ‘basis’ of system dynamics. In the reconstruction step, generator state variables such as rotor angles and voltage magnitudes are approximated with a linear combination of the characteristic generators, resulting in a quasi-nonlinear reduced model of the original external system. Network model is un-changed in the DEAR method. Tests on several IEEE standard systems show that the proposed method gets better reduction ratio and response errors than the traditional coherency aggregation methods.
Modeling and Evaluation of Geophysical Methods for Monitoring and Tracking CO2 Migration
Daniels, Jeff
2012-11-30T23:59:59.000Z
Geological sequestration has been proposed as a viable option for mitigating the vast amount of CO{sub 2} being released into the atmosphere daily. Test sites for CO{sub 2} injection have been appearing across the world to ascertain the feasibility of capturing and sequestering carbon dioxide. A major concern with full scale implementation is monitoring and verifying the permanence of injected CO{sub 2}. Geophysical methods, an exploration industry standard, are non-invasive imaging techniques that can be implemented to address that concern. Geophysical methods, seismic and electromagnetic, play a crucial role in monitoring the subsurface pre- and post-injection. Seismic techniques have been the most popular but electromagnetic methods are gaining interest. The primary goal of this project was to develop a new geophysical tool, a software program called GphyzCO2, to investigate the implementation of geophysical monitoring for detecting injected CO{sub 2} at test sites. The GphyzCO2 software consists of interconnected programs that encompass well logging, seismic, and electromagnetic methods. The software enables users to design and execute 3D surface-to-surface (conventional surface seismic) and borehole-to-borehole (cross-hole seismic and electromagnetic methods) numerical modeling surveys. The generalized flow of the program begins with building a complex 3D subsurface geological model, assigning properties to the models that mimic a potential CO{sub 2} injection site, numerically forward model a geophysical survey, and analyze the results. A test site located in Warren County, Ohio was selected as the test site for the full implementation of GphyzCO2. Specific interest was placed on a potential reservoir target, the Mount Simon Sandstone, and cap rock, the Eau Claire Formation. Analysis of the test site included well log data, physical property measurements (porosity), core sample resistivity measurements, calculating electrical permittivity values, seismic data collection, and seismic interpretation. The data was input into GphyzCO2 to demonstrate a full implementation of the software capabilities. Part of the implementation investigated the limits of using geophysical methods to monitor CO{sub 2} injection sites. The results show that cross-hole EM numerical surveys are limited to under 100 meter borehole separation. Those results were utilized in executing numerical EM surveys that contain hypothetical CO{sub 2} injections. The outcome of the forward modeling shows that EM methods can detect the presence of CO{sub 2}.
Vandersall, Jennifer A.; Gardner, Shea N.; Clague, David S.
2010-05-04T23:59:59.000Z
A computational method and computer-based system of modeling DNA synthesis for the design and interpretation of PCR amplification, parallel DNA synthesis, and microarray chip analysis. The method and system include modules that address the bioinformatics, kinetics, and thermodynamics of DNA amplification and synthesis. Specifically, the steps of DNA selection, as well as the kinetics and thermodynamics of DNA hybridization and extensions, are addressed, which enable the optimization of the processing and the prediction of the products as a function of DNA sequence, mixing protocol, time, temperature and concentration of species.
Boyer, Edmond
Hybrid Protein Model (HPM) : a method to compact protein 3D-structure information of the Seventh International Symposium on String Processing Information R #12;Hybrid Protein Model (HPM
Exponential control of overlap in the replica method for p-spin Sherrington-Kirkpatrick model
Dmitry Panchenko
2007-01-30T23:59:59.000Z
Recently, Michel Talagrand computed the large deviations limit $\\lim_{N\\to\\infty}(Na)^{-1}\\log \\e Z_N^a$ for the moments of the partition function $Z_N$ in the Sherrington-Kirkpatrick model for all real $a\\geq 0.$ For $a\\geq 1$ the limit is given by Guerra's inverse bound and this result extends the classical physicist's replica method that corresponds to integer $a.$ We give a new proof for $a\\geq 1$ in the case of the pure $p$-spin SK model that provides a strong exponential control of the overlap.
Long-time integration methods for mesoscopic models of pattern-forming systems
Abukhdeir, Nasser Mohieddin [Department of Chemical Engineering, University of Delaware, Newark, DE (United States); Vlachos, Dionisios G., E-mail: vlachos@udel.ed [Department of Chemical Engineering, University of Delaware, Newark, DE (United States); Katsoulakis, Markos [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA (United States); Department of Applied Mathematics, University of Crete, Heraklion (Greece); Institute of Applied and Computational Mathematics, Foundation for Research and Technology Hellas, Heraklion (Greece); Plexousakis, Michael [Department of Applied Mathematics, University of Crete, Heraklion (Greece); Institute of Applied and Computational Mathematics, Foundation for Research and Technology Hellas, Heraklion (Greece)
2011-06-20T23:59:59.000Z
Spectral methods for simulation of a mesoscopic diffusion model of surface pattern formation are evaluated for long simulation times. Backwards-differencing time-integration, coupled with an underlying Newton-Krylov nonlinear solver (SUNDIALS-CVODE), is found to substantially accelerate simulations, without the typical requirement of preconditioning. Quasi-equilibrium simulations of patterned phases predicted by the model are shown to agree well with linear stability analysis. Simulation results of the effect of repulsive particle-particle interactions on pattern relaxation time and short/long-range order are discussed.
Even-Parity S_(N) Adjoint Method Including SP_(N) Model Error and Iterative Efficiency
Zhang, Yunhuang
2014-08-10T23:59:59.000Z
In this Dissertation, we analyze an adjoint-based approach for assessing the model error of SP_(N) equations (low fidelity model) by comparing it against S_(N) equations (high fidelity model). Three model error estimation methods, namely, direct...
A method for solving stochastic equations by reduced order models and local approximations
Grigoriu, M., E-mail: mdg12@cornell.edu [Cornell University, Ithaca, NY 14853-3501 (United States)
2012-08-01T23:59:59.000Z
A method is proposed for solving equations with random entries, referred to as stochastic equations (SEs). The method is based on two recent developments. The first approximates the response surface giving the solution of a stochastic equation as a function of its random parameters by a finite set of hyperplanes tangent to it at expansion points selected by geometrical arguments. The second approximates the vector of random parameters in the definition of a stochastic equation by a simple random vector, referred to as stochastic reduced order model (SROM), and uses it to construct a SROM for the solution of this equation. The proposed method is a direct extension of these two methods. It uses SROMs to select expansion points, rather than selecting these points by geometrical considerations, and represents the solution by linear and/or higher order local approximations. The implementation and the performance of the method are illustrated by numerical examples involving random eigenvalue problems and stochastic algebraic/differential equations. The method is conceptually simple, non-intrusive, efficient relative to classical Monte Carlo simulation, accurate, and guaranteed to converge to the exact solution.
An efficient modeling method for thermal stratification simulation in a BWR suppression pool
Haihua Zhao; Ling Zou; Hongbin Zhang; Hua Li; Walter Villanueva; Pavel Kudinov
2012-09-01T23:59:59.000Z
The suppression pool in a BWR plant not only is the major heat sink within the containment system, but also provides major emergency cooling water for the reactor core. In several accident scenarios, such as LOCA and extended station blackout, thermal stratification tends to form in the pool after the initial rapid venting stage. Accurately predicting the pool stratification phenomenon is important because it affects the peak containment pressure; and the pool temperature distribution also affects the NPSHa (Available Net Positive Suction Head) and therefore the performance of the pump which draws cooling water back to the core. Current safety analysis codes use 0-D lumped parameter methods to calculate the energy and mass balance in the pool and therefore have large uncertainty in prediction of scenarios in which stratification and mixing are important. While 3-D CFD methods can be used to analyze realistic 3D configurations, these methods normally require very fine grid resolution to resolve thin substructures such as jets and wall boundaries, therefore long simulation time. For mixing in stably stratified large enclosures, the BMIX++ code has been developed to implement a highly efficient analysis method for stratification where the ambient fluid volume is represented by 1-D transient partial differential equations and substructures such as free or wall jets are modeled with 1-D integral models. This allows very large reductions in computational effort compared to 3-D CFD modeling. The POOLEX experiments at Finland, which was designed to study phenomena relevant to Nordic design BWR suppression pool including thermal stratification and mixing, are used for validation. GOTHIC lumped parameter models are used to obtain boundary conditions for BMIX++ code and CFD simulations. Comparison between the BMIX++, GOTHIC, and CFD calculations against the POOLEX experimental data is discussed in detail.
A Cutting Plane Method for Solving Harvest Scheduling Models with Area Restrictions
Brown, Sally
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 A Cutting Plane Method for Solving Harvest Scheduling Models with Area Restrictions N´ora K¨onnyua , S´andor F. T.e., clear-cuts) cannot exceed an area threshold in any given time period or over a set of periods called
Griffith, Daniel Todd
2005-02-17T23:59:59.000Z
computation and evaluation of partial derivatives with minimal user coding. The key results in this dissertation details the use of OCEA through a number of computational studies in estimation and dynamical modeling. Several prototype problems are studied... Embedding Method), has been recently developed which shows promise for efficient computation and evaluation of partial derivatives. For a rather arbitrary sequentially substituted set of functions, coded in FORTRAN 90, OCEA invokes operator overloading...
Kihm, IconKenneth David
transfer density. CONSTRUCTAL DESIGN: THE GENERATION OF MULTI-SCALE HEAT AND FLUID FLOW STRUCTURES-scale structures in natural convection with the objective of maximizing the heat transfer density, or the heat transfer rate per unit of volume§ . The flow volume is filled with vertical equidistant heated blades
Application of 2D-Nonlinear Shallow Water Model of Tsunami by using Adomian Decomposition Method
Waewcharoen, Sribudh; Boonyapibanwong, Supachai; Koonprasert, Sanoe [Department of Mathematics, King Mongkut's University of Technology, North Bangkok (Thailand)
2008-09-01T23:59:59.000Z
One of the most important questions in tsunami modeling is the estimation of tsunami run-up heights at different points along a coastline. Methods for numerical simulation of tsunami wave propagation in deep and shallow seas are well developed and have been widely used by many scientists (2001-2008). In this paper, we consider a two-dimensional nonlinear shallow water model of tsunami given by Tivon Jacobson is work [1]. u{sub t}+uu{sub x}+{nu}u{sub y} -c{sup 2}(h{sub x}+(h{sub b}){sub x}) {nu}{sub t}+u{nu}{sub x}+{nu}{nu}{sub y} = -c{sup 2}(h{sub y}+(h{sub b}){sub y}) h{sub t}+(hu){sub x}+(h{nu}){sub y} = 0 g-shore, h is surface elevation and s, t is time, u is velocity of cross-shore, {nu} is velocity of along-shore, h is surface elevation and h{sub b} is function of shore. This is a nondimensionalized model with the gravity g and constant reference depth H factored into c = {radical}(gH). We apply the Adomian Decompostion Method (ADM) to solve the tsunami model. This powerful method has been used to obtain explicit and numerical solutions of three types of diffusion-convection-reaction (DECR) equations. The ADM results for the tsunami model yield analytical solutions in terms of a rapidly convergent infinite power series. Symbolic computation, numerical results and graphs of solutions are obtained by Maple program.
An iterative stochastic ensemble method for parameter estimation of subsurface flow models
Elsheikh, Ahmed H., E-mail: aelsheikh@ices.utexas.edu [Center for Subsurface Modeling (CSM), Institute for Computational Engineering and Sciences (ICES), University of Texas at Austin, TX (United States); Dept. of Earth Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal (Saudi Arabia); Dept. of Applied Mathematics and Computational Sciences, King Abdullah University of Science and Technology (KAUST), Thuwal (Saudi Arabia); Wheeler, Mary F. [Center for Subsurface Modeling (CSM), Institute for Computational Engineering and Sciences (ICES), University of Texas at Austin, TX (United States)] [Center for Subsurface Modeling (CSM), Institute for Computational Engineering and Sciences (ICES), University of Texas at Austin, TX (United States); Hoteit, Ibrahim [Dept. of Earth Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal (Saudi Arabia) [Dept. of Earth Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal (Saudi Arabia); Dept. of Applied Mathematics and Computational Sciences, King Abdullah University of Science and Technology (KAUST), Thuwal (Saudi Arabia)
2013-06-01T23:59:59.000Z
Parameter estimation for subsurface flow models is an essential step for maximizing the value of numerical simulations for future prediction and the development of effective control strategies. We propose the iterative stochastic ensemble method (ISEM) as a general method for parameter estimation based on stochastic estimation of gradients using an ensemble of directional derivatives. ISEM eliminates the need for adjoint coding and deals with the numerical simulator as a blackbox. The proposed method employs directional derivatives within a Gauss–Newton iteration. The update equation in ISEM resembles the update step in ensemble Kalman filter, however the inverse of the output covariance matrix in ISEM is regularized using standard truncated singular value decomposition or Tikhonov regularization. We also investigate the performance of a set of shrinkage based covariance estimators within ISEM. The proposed method is successfully applied on several nonlinear parameter estimation problems for subsurface flow models. The efficiency of the proposed algorithm is demonstrated by the small size of utilized ensembles and in terms of error convergence rates.
Advanced statistical methods for eye movement analysis and modeling: a gentle introduction
Boccignone, Giuseppe
2015-01-01T23:59:59.000Z
In this Chapter we show that by considering eye movements, and in particular, the resulting sequence of gaze shifts, a stochastic process, a wide variety of tools become available for analyses and modelling beyond conventional statistical methods. Such tools encompass random walk analyses and more complex techniques borrowed from the pattern recognition and machine learning fields. After a brief, though critical, probabilistic tour of current computational models of eye movements and visual attention, we lay down the basis for gaze shift pattern analysis. To this end, the concepts of Markov Processes, the Wiener process and related random walks within the Gaussian framework of the Central Limit Theorem will be introduced. Then, we will deliberately violate fundamental assumptions of the Central Limit Theorem to elicit a larger perspective, rooted in statistical physics, for analysing and modelling eye movements in terms of anomalous, non-Gaussian, random walks and modern foraging theory. Eventually, by resort...
Modeling resonance interference by 0-D slowing-down solution with embedded self-shielding method
Liu, Y.; Martin, W. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI, 48109 (United States); Kim, K. S.; Williams, M. [Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37831-6172 (United States)
2013-07-01T23:59:59.000Z
The resonance integral table based methods employing conventional multigroup structure for the resonance self-shielding calculation have a common difficulty on treating the resonance interference. The problem arises due to the lack of sufficient energy dependence of the resonance cross sections when the calculation is performed in the multigroup structure. To address this, a resonance interference factor model has been proposed to account for the interference effect by comparing the interfered and non-interfered effective cross sections obtained from 0-D homogeneous slowing-down solutions by continuous-energy cross sections. A rigorous homogeneous slowing-down solver is developed with two important features for reducing the calculation time and memory requirement for practical applications. The embedded self-shielding method (ESSM) is chosen as the multigroup resonance self-shielding solver as an integral component of the interference method. The interference method is implemented in the DeCART transport code. Verification results show that the code system provides more accurate effective cross sections and multiplication factors than the conventional interference method for UO{sub 2} and MOX fuel cases. The additional computing time and memory for the interference correction is acceptable for the test problems including a depletion case with 87 isotopes in the fuel region. (authors)
Ray methods in the modelling of seismic wave elds Ivan P sen c k , Petr Bulant , Vlastislav
Cerveny, Vlastislav
and in the solution of forward and inverse problems of seismology and seismic exploration for oil. This contributionRay methods in the modelling of seismic wave #12;elds Ivan P#20;sen#20;c#19;#16;k #3; , Petr Bulant.cz Abstract Seismic ray method has broad applications in the numerical modelling of seismic wave #12;elds
Hunter, C.
2012-03-28T23:59:59.000Z
Several of the most common methods for estimating Pasquill-Gifford (PG) stability (turbulence) class were evaluated for use in modeling the radiological consequences of SRS accidental releases using the MELCOR Accident Consequence Code System, Ver. 2 (MACCS2). Evaluation criteria included: (1) the ability of the method to represent diffusion characteristics above a predominantly forested landscape at SRS, (2) suitability of the method to provide data consistent with the formulation of the MACCS2 model, and (3) the availability of onsite meteorological data to support implementation of the method The evaluation resulted in a recommendation that PG stability classification for regulatory applications at SRS should be based on measurements of the standard deviation of the vertical component of wind direction fluctuations, {sigma}{sub e}, collected from the 61-m level of the SRS meteorological towers, and processed in full accordance with EPA-454/R-99-005 (EPA, 2000). This approach provides a direct measurement that is fundamental to diffusion and captures explicitly the turbulence generated by both mechanical and buoyant forces over the characteristic surface (forested) of SRS. Furthermore, due to the potentially significant enhancement of horizontal fluctuations in wind direction from the occurrence of meander at night, the use of {sigma}{sub e} will ensure a reasonably conservative estimate of PG stability class for use in dispersion models that base diffusion calculations on a single value of PG stability class. Furthermore, meteorological data bases used as input for MACCS2 calculations should contain hourly data for five consecutive annual periods from the most recent 10 years.
Simulation of Thermal Stratification in BWR Suppression Pools with One Dimensional Modeling Method
Haihua Zhao; Ling Zou; Hongbin Zhang
2014-01-01T23:59:59.000Z
The suppression pool in a boiling water reactor (BWR) plant not only is the major heat sink within the containment system, but also provides the major emergency cooling water for the reactor core. In several accident scenarios, such as a loss-of-coolant accident and extended station blackout, thermal stratification tends to form in the pool after the initial rapid venting stage. Accurately predicting the pool stratification phenomenon is important because it affects the peak containment pressure; the pool temperature distribution also affects the NPSHa (available net positive suction head) and therefore the performance of the Emergency Core Cooling System and Reactor Core Isolation Cooling System pumps that draw cooling water back to the core. Current safety analysis codes use zero dimensional (0-D) lumped parameter models to calculate the energy and mass balance in the pool; therefore, they have large uncertainties in the prediction of scenarios in which stratification and mixing are important. While three-dimensional (3-D) computational fluid dynamics (CFD) methods can be used to analyze realistic 3-D configurations, these methods normally require very fine grid resolution to resolve thin substructures such as jets and wall boundaries, resulting in a long simulation time. For mixing in stably stratified large enclosures, the BMIX++ code (Berkeley mechanistic MIXing code in C++) has been developed to implement a highly efficient analysis method for stratification where the ambient fluid volume is represented by one-dimensional (1-D) transient partial differential equations and substructures (such as free or wall jets) are modeled with 1-D integral models. This allows very large reductions in computational effort compared to multi-dimensional CFD modeling. One heat-up experiment performed at the Finland POOLEX facility, which was designed to study phenomena relevant to Nordic design BWR suppression pool including thermal stratification and mixing, is used for validation. Comparisons between the BMIX++, GOTHIC, and CFD calculations against the POOLEX experimental data are discussed in detail.
A Penalty Method to Model Particle Interactions in DNA-laden Flows
Trebotich, D; Miller, G H; Bybee, M D
2006-10-06T23:59:59.000Z
We present a hybrid fluid-particle algorithm to simulate flow and transport of DNA-laden fluids in microdevices. Relevant length scales in microfluidic systems range from characteristic channel sizes of millimeters to micron scale geometric variation (e.g., post arrays) to 10 nanometers for the length of a single rod in a bead-rod polymer representation of a biological material such as DNA. The method is based on a previous fluid-particle algorithm in which long molecules are represented as a chain of connected rods, but in which the physically unrealistic behavior of rod crossing occurred. We have extended this algorithm to include screened Coulombic forces between particles by implementing a Debye-Hueckel potential acting between rods. In the method an unsteady incompressible Newtonian fluid is discretized with a second-order finite difference method in the interior of the Cartesian grid domain; an embedded boundary volume-of-fluid formulation is used near boundaries. The bead-rod polymer model is fully coupled to the solvent through body forces representing hydrodynamic drag and stochastic thermal fluctuations. While intrapolymer interactions are modeled by a soft potential, polymer-structure interactions are treated as perfectly elastic collisions. We demonstrate this method on flow and transport of a polymer through a post array microchannel in 2D where the polymer incorporates more realistic physical parameters of DNA, and compare to previous simulations where rods are allowed to cross. We also show that the method is capable of simulating 3D flow in a packed bed micro-column.
A Method for Modeling Household Occupant Behavior to Simulate Residential Energy Consumption
Johnson, Brandon J [ORNL] [ORNL; Starke, Michael R [ORNL] [ORNL; Abdelaziz, Omar [ORNL] [ORNL; Jackson, Roderick K [ORNL] [ORNL; Tolbert, Leon M [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK)
2014-01-01T23:59:59.000Z
This paper presents a statistical method for modeling the behavior of household occupants to estimate residential energy consumption. Using data gathered by the U.S. Census Bureau in the American Time Use Survey (ATUS), actions carried out by survey respondents are categorized into ten distinct activities. These activities are defined to correspond to the major energy consuming loads commonly found within the residential sector. Next, time varying minute resolution Markov chain based statistical models of different occupant types are developed. Using these behavioral models, individual occupants are simulated to show how an occupant interacts with the major residential energy consuming loads throughout the day. From these simulations, the minimum number of occupants, and consequently the minimum number of multiple occupant households, needing to be simulated to produce a statistically accurate representation of aggregate residential behavior can be determined. Finally, future work will involve the use of these occupant models along side residential load models to produce a high-resolution energy consumption profile and estimate the potential for demand response from residential loads.
Plys, Martin; Burelbach, James; Lee, Sung Jin; Apthorpe, Robert [Fauske and Associates, LLC, 16W070 83rd St., Burr Ridge, IL, 60527 (United States)] [Fauske and Associates, LLC, 16W070 83rd St., Burr Ridge, IL, 60527 (United States)
2013-07-01T23:59:59.000Z
A unified modeling method applicable to the processing, shipping, and storage of spent nuclear fuel and sludge has been incrementally developed, validated, and applied over a period of about 15 years at the US DOE Hanford site. The software, FATE{sup TM}, provides a consistent framework for a wide dynamic range of common DOE and commercial fuel and waste applications. It has been used during the design phase, for safety and licensing calculations, and offers a graded approach to complex modeling problems encountered at DOE facilities and abroad (e.g., Sellafield). FATE has also been used for commercial power plant evaluations including reactor building fire modeling for fire PRA, evaluation of hydrogen release, transport, and flammability for post-Fukushima vulnerability assessment, and drying of commercial oxide fuel. FATE comprises an integrated set of models for fluid flow, aerosol and contamination release, transport, and deposition, thermal response including chemical reactions, and evaluation of fire and explosion hazards. It is one of few software tools that combine both source term and thermal-hydraulic capability. Practical examples are described below, with consideration of appropriate model complexity and validation. (authors)
RodrĂguez, Rodolfo
Numerical analysis of a finite element method for the axisymmetric eddy current model, 27002, Lugo, Spain The aim of this paper is to analyze a finite element method to solve an eddy current of the method are reported. Keywords: low-frequency harmonic Maxwell equations, eddy current problems, finite
Deformed Hamilton-Jacobi Method in Covariant Quantum Gravity Effective Models
Mu Benrong; Peng Wang; Haitang Yang
2014-08-21T23:59:59.000Z
We first briefly revisit the original Hamilton-Jacobi method and show that the Hamilton-Jacobi equation for the action $I$ of tunnelings of a fermionic particle from a charged black hole can be written in the same form as that of a scalar particle. For the low energy quantum gravity effective models which respect covariance of the curved spacetime, we derive the deformed model-independent KG/Dirac and Hamilton-Jacobi equations using the methods of effective field theory. We then find that, to all orders of the effective theories, the deformed Hamilton-Jacobi equations can be obtained from the original ones by simply replacing the mass of emitted particles $m$ with a parameter $m_{eff}$ that includes all the quantum gravity corrections. Therefore, in this scenario, there will be no corrections to the Hawking temperature of a black hole from the quantum gravity effects if its original Hawking temperature is independent of the mass of emitted particles. As a consequence, our results show that breaking covariance in quantum gravity effective models is a key for a black hole to have the remnant left in the evaporation.
Multi-scale investigation of sheared flows in magnetized plasmas
Thomas, Jr., Dr. Edward
2014-09-19T23:59:59.000Z
Flows parallel and perpendicular to magnetic fields in a plasma are important phenomena in many areas of plasma science research. The presence of these spatially inhomogeneous flows is often associated with the stability of the plasma. In fusion plasmas, these sheared flows can be stabilizing while in space plasmas, these sheared flows can be destabilizing. Because of this, there is broad interest in understanding the coupling between plasma stability and plasma flows. This research project has engaged in a study of the plasma response to spatially inhomogeneous plasma flows using three different experimental devices: the Auburn Linear Experiment for Instability Studies (ALEXIS) and the Compact Toroidal Hybrid (CTH) stellarator devices at Auburn University, and the Space Plasma Simulation Chamber (SPSC) at the Naval Research Laboratory. This work has shown that there is a commonality of the plasma response to sheared flows across a wide range of plasma parameters and magnetic field geometries. The goal of this multi-device, multi-scale project is to understand how sheared flows established by the same underlying physical mechanisms lead to different plasma responses in fusion, laboratory, and space plasmas.
Toni Smithl; Lyudmila V. Slipchenko; Mark S. Gordon
2008-02-27T23:59:59.000Z
This study compares the results of the general effective fragment potential (EFP2) method to the results of a previous combined coupled cluster with single, double, and perturbative triple excitations [CCSD(T)] and symmetry-adapted perturbation theory (SAPT) study [Sinnokrot and Sherrill, J. Am. Chem. Soc., 2004, 126, 7690] on substituent effects in {pi}-{pi} interactions. EFP2 is found to accurately model the binding energies of the benzene-benzene, benzene-phenol, benzene-toluene, benzene-fluorobenzene, and benzene-benzonitrile dimers, as compared with high-level methods [Sinnokrot and Sherrill, J. Am. Chem. Soc., 2004, 126, 7690], but at a fraction of the computational cost of CCSD(T). In addition, an EFP-based Monte Carlo/simulated annealing study was undertaken to examine the potential energy surface of the substituted dimers.
a a twostep scheme for natural gas combustion [30] coupled with a simplified turbulent kinetics model [6An Embedded Boundary Method for the Modeling of Unsteady Combustion in an Industrial Gas the simulation of an experimental natural gasfired furnace are shown. 1 Introduction The ability to model
Jenny, Bernhard
This course teaches essential methods, algorithms, and data models for building geospatial software. Students are introduced to raster and vector data models and algorithms for the manipulation of this course, algorithms for modeling, analyzing and visualizing geographic informa- tion are discussed
Long Gamma-Ray Bursts Calibrated by Pade Method and Constraints on Cosmological Models
Jing Liu; Hao Wei
2014-10-15T23:59:59.000Z
Gamma-ray bursts (GRBs) are among the most powerful sources in the universe. In the recent years, GRBs have been proposed as a complementary probe to type Ia supernovae (SNIa). However, as is well known, there is a circularity problem in the use of GRBs to study cosmology. In this work, based on the Pad\\'e approximant, we propose a new cosmology-independent method to calibrate GRBs. We consider a sample consisting 138 long GRBs and obtain 79 calibrated long GRBs at high redshift $z>1.4$ (named Mayflower sample) which can be used to constrain cosmological models without the circularity problem. Then, we consider the constraints on several cosmological models with these 79 calibrated GRBs and other observational data. We show that GRBs are competent to be a complementary probe to the other well-established cosmological observations.
A Realizability-Preserving Discontinuous Galerkin Method for the $M_1$ Model of Radiative Transfer
Frank, Martin [RWTH Aachen University; Olbrant, Edgar [RWTH Aachen University; Hauck, Cory D [ORNL
2012-01-01T23:59:59.000Z
The M{sub 1} model for radiative transfer coupled to a material energy equation in planar geometry is studied in this paper. For this model to be well-posed, its moment variables must fulfill certain realizability conditions. Our main focus is the design and implementation of an explicit Runge-Kutta discontinuous Galerkin method which, under a more restrictive CFL condition, guarantees the realizability of the moment variables and the positivity of the material temperature. An analytical proof for our realizability-preserving scheme, which also includes a slope-limiting technique, is provided and confirmed by various numerical examples. Among other things, we present accuracy tests showing convergence up to fourth-order, compare our results with an analytical solution in a Riemann problem, and consider a Marshak wave problem.
Advanced methods for uncertainty quantification in tail regions of climate model predictions.
Safta, Cosmin; Debusschere, Bert J.; Najm, Habib N.; Sargsyan, Khachik
2010-09-01T23:59:59.000Z
Conventional methods for uncertainty quantification are generally challenged in the 'tails' of probability distributions. This is specifically an issue for many climate observables since extensive sampling to obtain a reasonable accuracy in tail regions is especially costly in climate models. Moreover, the accuracy of spectral representations of uncertainty is weighted in favor of more probable ranges of the underlying basis variable, which, in conventional bases does not particularly target tail regions. Therefore, what is ideally desired is a methodology that requires only a limited number of full computational model evaluations while remaining accurate enough in the tail region. To develop such a methodology, we explore the use of surrogate models based on non-intrusive Polynomial Chaos expansions and Galerkin projection. We consider non-conventional and custom basis functions, orthogonal with respect to probability distributions that exhibit fat-tailed regions. We illustrate how the use of non-conventional basis functions, and surrogate model analysis, improves the accuracy of the spectral expansions in the tail regions. Finally, we also demonstrate these methodologies using precipitation data from CCSM simulations.
Interactive Rapid Dose Assessment Model (IRDAM): reactor-accident assessment methods. Vol. 2
Poeton, R.W.; Moeller, M.P.; Laughlin, G.J.; Desrosiers, A.E.
1983-05-01T23:59:59.000Z
As part of the continuing emphasis on emergency preparedness, the US Nuclear Regulatory Commission (NRC) sponsored the development of a rapid dose assessment system by Pacific Northwest Laboratory (PNL). This system, the Interactive Rapid Dose Assessment Model (IRDAM) is a micro-computer based program for rapidly assessing the radiological impact of accidents at nuclear power plants. This document describes the technical bases for IRDAM including methods, models and assumptions used in calculations. IRDAM calculates whole body (5-cm depth) and infant thyroid doses at six fixed downwind distances between 500 and 20,000 meters. Radionuclides considered primarily consist of noble gases and radioiodines. In order to provide a rapid assessment capability consistent with the capacity of the Osborne-1 computer, certain simplifying approximations and assumptions are made. These are described, along with default values (assumptions used in the absence of specific input) in the text of this document. Two companion volumes to this one provide additional information on IRDAM. The user's Guide (NUREG/CR-3012, Volume 1) describes the setup and operation of equipment necessary to run IRDAM. Scenarios for Comparing Dose Assessment Models (NUREG/CR-3012, Volume 3) provides the results of calculations made by IRDAM and other models for specific accident scenarios.
Tsakalides, Panagiotis
grey: Pacific ocean, LAX, freeway system. · Dark grey: mountain slops · Lighter grey: suburban areas: ·· Oil spill boundaries on waterOil spill boundaries on water ·· Changes in delicate ecosystems
Deformed Hamilton-Jacobi Method in Covariant Quantum Gravity Effective Models
Benrong, Mu; Yang, Haitang
2014-01-01T23:59:59.000Z
We first briefly revisit the original Hamilton-Jacobi method and show that the Hamilton-Jacobi equation for the action $I$ of tunnelings of a fermionic particle from a charged black hole can be written in the same form as that of a scalar particle. For the low energy quantum gravity effective models which respect covariance of the curved spacetime, we derive the deformed model-independent KG/Dirac and Hamilton-Jacobi equations using the methods of effective field theory. We then find that, to all orders of the effective theories, the deformed Hamilton-Jacobi equations can be obtained from the original ones by simply replacing the mass of emitted particles $m$ with a parameter $m_{eff}$ that includes all the quantum gravity corrections. Therefore, in this scenario, there will be no corrections to the Hawking temperature of a black hole from the quantum gravity effects if its original Hawking temperature is independent of the mass of emitted particles. As a consequence, our results show that breaking covariance...
Shell model method for Gamow-Teller transitions in heavy, deformed nuclei
Gao Zaochun [Joint Institute for Nuclear Astrophysics and Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); China Institute of Atomic Energy, P.O. Box 275 (18), Beijing 102413 (China); Sun Yang [Joint Institute for Nuclear Astrophysics and Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Chen, Y.-S. [China Institute of Atomic Energy, P.O. Box 275(18), Beijing 102413 (China); Institute of Theoretical Physics, Academia Sinica, Beijing 100080 (China)
2006-11-15T23:59:59.000Z
A method for calculation of Gamow-Teller transition rates is developed by using the concept of the Projected Shell Model (PSM). The shell model basis is constructed by superimposing angular-momentum-projected multiquasiparticle configurations, and nuclear wave functions are obtained by diagonalizing the two-body interactions in these projected states. Calculation of transition matrix elements in the PSM framework is discussed in detail, and the effects caused by the Gamow-Teller residual forces and by configuration-mixing are studied. With this method, it may become possible to perform a state-by-state calculation for {beta}-decay and electron-capture rates in heavy, deformed nuclei at finite temperatures. Our first example indicates that, while experimentally known Gamow-Teller transition rates from the ground state of the parent nucleus are reproduced, stronger transitions from some low-lying excited states are predicted to occur, which may considerably enhance the total decay rates once these nuclei are exposed to hot stellar environments.
Takahiro Mizusaki; Noritaka Shimizu
2012-01-27T23:59:59.000Z
We propose a new variational Monte Carlo (VMC) method with an energy variance extrapolation for large-scale shell-model calculations. This variational Monte Carlo is a stochastic optimization method with a projected correlated condensed pair state as a trial wave function, and is formulated with the M-scheme representation of projection operators, the Pfaffian and the Markov-chain Monte Carlo (MCMC). Using this method, we can stochastically calculate approximated yrast energies and electro-magnetic transition strengths. Furthermore, by combining this VMC method with energy variance extrapolation, we can estimate exact shell-model energies.
Michael R Tonks; Yongfeng Zhang; Xianming Bai
2014-06-01T23:59:59.000Z
This report summarizes development work funded by the Nuclear Energy Advanced Modeling Simulation program's Fuels Product Line (FPL) to develop a mechanistic model for the average grain size in UO? fuel. The model is developed using a multiscale modeling and simulation approach involving atomistic simulations, as well as mesoscale simulations using INL's MARMOT code.
McKittrick, Joanna
Elastic moduli of untreated, demineralized and deproteinized cortical bone: Validation online 15 November 2011 Keywords: Cortical bone Elastic moduli Multi-scale modeling Demineralization include completely demineralized and deproteinized bones as well as untreated bone samples. Porosity
Tsai, Yue-Lin Sming [National Center for Nuclear Research, Hoza 69, 00-681 Warsaw (Poland); Yuan, Qiang [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P.R.China (China); Huang, Xiaoyuan, E-mail: Sming.Tsai@fuw.edu.pl, E-mail: yuanq@ihep.ac.cn, E-mail: x_huang@bao.ac.cn [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, P.R.China (China)
2013-03-01T23:59:59.000Z
Observation of ?-rays from dwarf galaxies is an effective way to search for particle dark matter. Using 4-year data of Fermi-LAT observations on a series of Milky Way satellites, we develop a general way to search for the signals from dark matter annihilation in such objects. Instead of giving prior information about the energy spectrum of dark matter annihilation, we bin the Fermi-LAT data into several energy bins and build a likelihood map in the ''energy bin - flux'' plane. The final likelihood of any spectrum can be easily derived through combining the likelihood of all the energy bins. It gives consistent result with that directly calculated using the Fermi Scientific Tool. This method is very efficient for the study of any specific dark matter models with ?-rays. We use the new likelihood map with Fermi-LAT 4 year data to fit the parameter space in three representative dark matter models: i) toy dark matter model, ii) effective dark matter operators, and iii) supersymmetric neutralino dark matter.
Tidal Downsizing model. I. Numerical methods: saving giant planets from tidal disruptions
Nayakshin, Sergei
2014-01-01T23:59:59.000Z
Tidal Downsizing (TD) is a recently developed planet formation theory that supplements the classical Gravitational disc Instability (GI) model with planet migration inward and tidal disruptions of GI fragments in the inner regions of the disc. Numerical methods for a detailed population synthesis of TD planets are presented here. As an example application, the conditions under which GI fragments collapse faster than they migrate into the inner $a\\sim$ few AU disc are considered. It is found that most gas fragments are tidally or thermally disrupted unless (a) their opacity is $\\sim 3$ orders of magnitude less than the interstellar dust opacity at metallicities typical of the observed giant planets, or (b) the opacity is high but the fragments accrete large dust grains (pebbles) from the disc. Case (a) models produce very low mass solid cores ($M_{\\rm core} < 0.1$ Earth masses) and follow a negative correlation of giant planet frequency with host star metallicity. In contrast, case (b) models produce massiv...
Commercial Implementation of Model-Based Manufacturing of Nanostructured Metals
Lowe, Terry C. [Los Alamos National Laboratory
2012-07-24T23:59:59.000Z
Computational modeling is an essential tool for commercial production of nanostructured metals. Strength is limited by imperfections at the high strength levels that are achievable in nanostructured metals. Processing to achieve homogeneity at the micro- and nano-scales is critical. Manufacturing of nanostructured metals is intrinsically a multi-scale problem. Manufacturing of nanostructured metal products requires computer control, monitoring and modeling. Large scale manufacturing of bulk nanostructured metals by Severe Plastic Deformation is a multi-scale problem. Computational modeling at all scales is essential. Multiple scales of modeling must be integrated to predict and control nanostructural, microstructural, macrostructural product characteristics and production processes.
Multi-Scale Gradient Expansion of the Turbulent Stress Tensor
Gregory L. Eyink
2005-12-10T23:59:59.000Z
We develop an expansion of the turbulent stress tensor into a double series of contributions from different scales of motion and different orders of space-derivatives of velocity, a Multi-Scale Gradient (MSG) expansion. The expansion is proved to converge to the exact stress, as a consequence of the locality of cascade both in scale and in space. Simple estimates show, however, that the convergence rate may be slow for the expansion in spatial gradients of very small scales. Therefore, we develop an approximate expansion, based upon an assumption that similar or `coherent' contributions to turbulent stress are obtained from disjoint subgrid regions. This Coherent-Subregions Approximation (CSA) yields an MSG expansion that can be proved to converge rapidly at all scales and is hopefully still reasonably accurate. As an application, we consider the cascades of energy and helicity in three-dimensional turbulence. To first order in velocity-gradients, the stress has three contributions: a tensile stress along principal directions of strain, a contractile stress along vortex lines, and a shear stress proportional to `skew-strain.' While vortex-stretching plays the major role in energy cascade, there is a second, less scale-local contribution from `skew-strain'. For helicity cascade the situation is reversed, and it arises scale-locally from `skew-strain' while the stress along vortex-lines gives a secondary, less scale-local contribution. These conclusions are illustrated with simple exact solutions of 3D Euler equations. In the first, energy cascade occurs by Taylor's mechanism of stretching and spin-up of small-scale vortices due to large-scale strain. In the second, helicity cascade occurs by `twisting' of small-scale vortex filaments due to a large-scale screw.
An Embedded Boundary Method for the Modeling of Unsteady Combustion in an Industrial Gas the simulation of an experimental natural gasfired furnace are shown. \\Lambda This work was performed under
Lucio Mayer; Stelios Kazantzidis; Andres Escala
2008-07-22T23:59:59.000Z
(Abridged) We review the results of the first multi-scale, hydrodynamical simulations of mergers between galaxies with central supermassive black holes (SMBHs) to investigate the formation of SMBH binaries in galactic nuclei. We demonstrate that strong gas inflows produce nuclear disks at the centers of merger remnants whose properties depend sensitively on the details of gas thermodynamics. In numerical simulations with parsec-scale spatial resolution in the gas component and an effective equation of state appropriate for a starburst galaxy, we show that a SMBH binary forms very rapidly, less than a million years after the merger of the two galaxies. Binary formation is significantly suppressed in the presence of a strong heating source such as radiative feedback by the accreting SMBHs. We also present preliminary results of numerical simulations with ultra-high spatial resolution of 0.1 pc in the gas component. These simulations resolve the internal structure of the resulting nuclear disk down to parsec scales and demonstrate the formation of a central massive object (~ 10^8 Mo) by efficient angular momentum transport. This is the first time that a radial gas inflow is shown to extend to parsec scales as a result of the dynamics and hydrodynamics involved in a galaxy merger, and has important implications for the fueling of SMBHs. Due to the rapid formation of the central clump, the density of the nuclear disk decreases significantly in its outer region, reducing dramatically the effect of dynamical friction and leading to the stalling of the two SMBHs at a separation of ~1 pc. We discuss how the orbital decay of the black holes might continue in a more realistic model which incorporates star formation and the multi-phase nature of the ISM.
Ontological Investigation of Ecosystem Hierarchies and Formal Theory for Multiscale Ecosystem
Bittner, Thomas
Ontological Investigation of Ecosystem Hierarchies and Formal Theory for Multiscale Ecosystem at Buffalo sorokine@buffalo.edu 2 Institute of Formal Ontology and Medical Information Systems, Leipzig thomas.bittner@ifomis.uni-leipzig.de 3 National Center for Geographic Information and Analysis (NCGIA
POPULATION, MULTI-SCALE PROCESSES, AND LAND USE TRANSITIONSIN WilliamKY Pan
Lopez-Carr, David
POPULATION, MULTI-SCALE PROCESSES, AND LAND USE TRANSITIONSIN THE AMAZON WilliamKY Pan DavidL. Carr focusedon anddebatedthe drivers of LUCC, such as the influence of population dynamics (Carr et al 2006; Allen andBarnes 1985; Barbieri andCarr 2005; Mather andNeedle 2000; Pan et al. 2007; Armenterasaet al
Chip-Package Co-Simulation with Multiscale Structures Myunghyun Ha1
Swaminathan, Madhavan
Chip-Package Co-Simulation with Multiscale Structures Myunghyun Ha1 , Krishna Srinivasan2 and Madhavan Swaminathan3 Packaging Research Center School of Electrical and Computer Engineering, Georgia-404-894-3842 { 1 mha, 2 krishna, 3 madhavan.swaminathan } @ece.gatech.edu Abstract Chip-package co
Multi-scale Demand-Side Management for Continuous Power-intensive Processes
Grossmann, Ignacio E.
1 Multi-scale Demand-Side Management for Continuous Power-intensive Processes Sumit Mitra Advisor, PA Collaborators: Jose M. Pinto (Praxair), Nikhil Arora (Praxair) #12;Demand-Side Management (DSM Demand-Side Management (DSM) "Systematic utility and government activities designed to change the amount
Adaptive Multiscale Molecular Dynamics of Macromolecular Fluids Steven O. Nielsen,1
Nielsen, Steven O.
diffusion in polymer electrolytes, signal transduction be- tween proteins, nanostructure formationAdaptive Multiscale Molecular Dynamics of Macromolecular Fluids Steven O. Nielsen,1 Preston B 2010; published 3 December 2010) Until now, adaptive atomisticcoarse-grain (A/CG) molecular dynamics
Charge mobility of discotic mesophases: A multiscale quantum/classical study
J. Kirkpatrick; V. Marcon; J. Nelson; K. Kremer; D. Andrienko
2007-01-16T23:59:59.000Z
A correlation is established between the molecular structure and charge mobility of discotic mesophases of hexabenzocoronene derivatives by combining electronic structure calculations, Molecular Dynamics, and kinetic Monte Carlo simulations. It is demonstrated that this multiscale approach can provide an accurate ab-initio description of charge transport in organic materials.
Non-Destructive Whole Lung Assessment via Multi-scale Micro CT Imaging Combined with Stereology
Wang, Ge
Non-Destructive Whole Lung Assessment via Multi-scale Micro CT Imaging Combined with Stereology Tech, Virginia, USA Running head Non-Destructive Whole Lung Assessment via µCT Contact Information Eric-hoffman@uiowa.edu Phone: 319-353-6213 Fax: 319-356-1503 #12;Abstract Estimating volume fractions of the lung parenchyma
3D multi-scale imaging of experimental fracture generation in shale gas reservoirs.
Henderson, Gideon
in research and shale unconventional reservoirs that will provide you with the skills to enter the oil and gas3D multi-scale imaging of experimental fracture generation in shale gas reservoirs. Supervisory-grained organic carbon-rich rocks (shales) are increasingly being targeted as shale gas "reservoirs". Due
Multiscale analysis of three consecutive years of anomalous flooding in Pakistan
Houze Jr., Robert A.
Multiscale analysis of three consecutive years of anomalous flooding in Pakistan By K. L. Rasmussen investigation into three years of anomalous floods in Pakistan provides insight into their formation, unifying for the formation of anomalous easterly midlevel flow across central India into Pakistan that advected deep
A Multiscale Study of High Performance Double-Walled Nanotube Polymer
Espinosa, Horacio D.
- tinuous CNT yarns from CVD grown CNT aerogels.1,2,34 The stretching of the low den- sity aerogels of CNTs of randomly oriented bundles of DWNTs thinly coated with polymeric organic compounds. A multiscale in situ performance of yarns and isolated DWNT bundles with and without polymer coatings. DWNT polymer yarns exhibited
CONTAM 01 MultiScale Soil Sensor Network in Support of Groundwater Quality Team Members
California at Los Angeles, University of
CONTAM 01 MultiScale Soil Sensor Network in Support of Groundwater Quality Protection Team Members of the ongoing CENS investigation into reclaimed wastewater infiltration into shallow soils and groundwater recharge. Groundwater resources are typically over-drafted during dry periods in arid and semi
Multi-scale Complexity Analysis on the Sequence of E. coli Complete Genome
Ren, Kui
Multi-scale Complexity Analysis on the Sequence of E. coli Complete Genome Jin Wang1 , Qidong Zhang-scale density distribution of nucleotides from the complete Escherichia coli genome by applying the newly density distribution of bases from this genome was obtained. Especially we have discovered that G, C
Multi-scale mechanical improvement produced in carbon nanotube fibers by irradiation cross-linking
Espinosa, Horacio D.
Review Multi-scale mechanical improvement produced in carbon nanotube fibers by irradiation cross devoted to studying such cross-linking by the irradiation of CNT based materials using either high energy particles, such as elec- trons, to directly covalently cross-link CNTs, or electromagnetic irradiation
Boyer, Edmond
The Geological Society Special Publication - 1 - Multiscale fracture analysis along the French Philippe Lebon, BP 540, 76 058 Le Havre Cedex, France 3. Applied Geology Research Unit, University version to the Geological Society of London : 20th March 2003 Special issue: "Coastal chalk cliff
ISO-SWS calibration and the accurate modelling of cool-star atmospheres: I. Method
L. Decin; C. Waelkens; K. Eriksson; B. Gustafsson; B. Plez; A. J. Sauval; W. Van Assche; B. Vandenbussche
2000-08-21T23:59:59.000Z
A detailed spectroscopic study of the ISO-SWS data of the red giant Alpha Tau is presented, which enables not only the accurate determination of the stellar parameters of Alpha Tau, but also serves as a critical review of the ISO-SWS calibration. This study is situated in a broader context of an iterative process in which both accurate observations of stellar templates and cool star atmosphere models are involved to improve the ISO-SWS calibration process as well as the theoretical modelling of stellar atmospheres. Therefore a sample of cool stars, covering the whole A0 -- M8 spectral classification, has been observed in order to disentangle calibration problems and problems in generating the theoretical models and corresponding synthetic spectrum. By using stellar parameters found in the literature large discrepancies were seen between the ISO-SWS data and the generated synthetic spectrum of Alpha Tau. A study of the influence of various stellar parameters on the theoretical models and synthetic spectra, in conjunction with the Kolmogorov-Smirnov test to evaluate objectively the goodness-of-fit, enables us to pin down the stellar parameters with a high accuracy: Teff = 3850 +/- 70 K, log g = 1.50 +/- 0.15, M = 2.3 +/- 0.8 Msun, z = -0.15 +/- 0.20 dex, microturbulence = 1.7 +/- 0.3 km/s, 12C/13C= 10 +/- 1, abundance of C = 8.35 +/- 0.20 dex, abundance of N= 8.35 +/- 0.25 dex, abundance of O = 8.83 +/- 0.15 dex and the angular diameter is 20.77 +/- 0.83 mas. These atmospheric parameters were then compared with the results provided by other authors using other methods and/or spectra.
T. A. Carroll; M. Kopf; K. G. Strassmeier
2008-07-24T23:59:59.000Z
The major challenges for a fully polarized radiative transfer driven approach to Zeeman-Doppler imaging are still the enormous computational requirements. In every cycle of the iterative interplay between the forward process (spectral synthesis) and the inverse process (derivative based optimization) the Stokes profile synthesis requires several thousand evaluations of the polarized radiative transfer equation for a given stellar surface model. To cope with these computational demands and to allow for the incorporation of a full Stokes profile synthesis into Doppler- and Zeeman-Doppler imaging applications as well as into large scale solar Stokes profile inversions, we present a novel fast and accurate synthesis method for calculating local Stokes profiles. Our approach is based on artificial neural network models, which we use to approximate the complex non-linear mapping between the most important atmospheric parameters and the corresponding Stokes profiles. A number of specialized artificial neural networks, are used to model the functional relation between the model atmosphere, magnetic field strength, field inclination, and field azimuth, on one hand and the individual components (I,Q,U,V) of the Stokes profiles, on the other hand. We performed an extensive statistical evaluation and show that our new approach yields accurate local as well as disk-integrated Stokes profiles over a wide range of atmospheric conditions. The mean rms errors for the Stokes I and V profiles are well below 0.2% compared to the exact numerical solution. Errors for Stokes Q and U are in the range of 1%. Our approach does not only offer an accurate approximation to the LTE polarized radiative transfer it, moreover, accelerates the synthesis by a factor of more than 1000.
Liu, C.; Zeig, M.; Claridge, D. E.; Wei, G.; Bruner, H.; Turner, W. D.
2005-01-01T23:59:59.000Z
A Method for Simulating Heat Recovery Systems Using AirModel in Implementations of the ASHRAE Simplified Energy Analysis Procedure Chenggang Liu Research Associate Energy Systems Laboratory Texas A&M University College Station, TX Marvin..., TX W. Dan Turner, Ph.D., P.E. Professor & Director Energy Systems Laboratory Texas A&M University College Station, TX Abstract A method for simulating heat recovery systems using AirModel in implementations of the ASHRAE simplified...
Liu, C.; Zeig, M.; Claridge, D. E.; Wei, G.; Bruner, H.; Turner, W. D.
2005-01-01T23:59:59.000Z
A Method for Simulating Heat Recovery Systems Using AirModel in Implementations of the ASHRAE Simplified Energy Analysis Procedure Chenggang Liu Research Associate Energy Systems Laboratory Texas A&M University College Station, TX Marvin..., TX W. Dan Turner, Ph.D., P.E. Professor & Director Energy Systems Laboratory Texas A&M University College Station, TX Abstract A method for simulating heat recovery systems using AirModel in implementations of the ASHRAE simplified...
Fix, N. J.
2008-01-31T23:59:59.000Z
The purpose of the project is to conduct research at an Integrated Field-Scale Research Challenge Site in the Hanford Site 300 Area, CERCLA OU 300-FF-5 (Figure 1), to investigate multi-scale mass transfer processes associated with a subsurface uranium plume impacting both the vadose zone and groundwater. The project will investigate a series of science questions posed for research related to the effect of spatial heterogeneities, the importance of scale, coupled interactions between biogeochemical, hydrologic, and mass transfer processes, and measurements/approaches needed to characterize a mass-transfer dominated system. The research will be conducted by evaluating three (3) different hypotheses focused on multi-scale mass transfer processes in the vadose zone and groundwater, their influence on field-scale U(VI) biogeochemistry and transport, and their implications to natural systems and remediation. The project also includes goals to 1) provide relevant materials and field experimental opportunities for other ERSD researchers and 2) generate a lasting, accessible, and high-quality field experimental database that can be used by the scientific community for testing and validation of new conceptual and numerical models of subsurface reactive transport.
Phoha, Vir V.
An Interactive Dynamic Model for Integrating Knowledge Management Methods and Knowledge Sharing Technology in a Traditional Classroom Vir V. Phoha Computer Science Louisiana Tech University Ruston, LA Management methods and Knowledge Sharing technology to integrate the acquisition of skills and relevant