Issues in adaptive mesh refinement
Dai, William Wenlong [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
In this paper, we present an approach for a patch-based adaptive mesh refinement (AMR) for multi-physics simulations. The approach consists of clustering, symmetry preserving, mesh continuity, flux correction, communications, and management of patches. Among the special features of this patch-based AMR are symmetry preserving, efficiency of refinement, special implementation offlux correction, and patch management in parallel computing environments. Here, higher efficiency of refinement means less unnecessarily refined cells for a given set of cells to be refined. To demonstrate the capability of the AMR framework, hydrodynamics simulations with many levels of refinement are shown in both two- and three-dimensions.
On Adaptive Mesh Refinement for Atmospheric Pollution Models
Sandu, Adrian
On Adaptive Mesh Refinement for Atmospheric Pollution Models Emil M. Constantinescu and Adrian res- olution system for modeling regional air pollution based on the chemical transport model STEM. Keywords: Air Pollution Modeling, Adaptive Mesh Refinement. 1 Introduction Inadequate grid resolution can
GRChombo : Numerical Relativity with Adaptive Mesh Refinement
Katy Clough; Pau Figueras; Hal Finkel; Markus Kunesch; Eugene A. Lim; Saran Tunyasuvunakool
2015-03-11T23:59:59.000Z
Numerical relativity has undergone a revolution in the past decade. With a well-understood mathematical formalism, and full control over the gauge modes, it is now entering an era in which the science can be properly explored. In this work, we introduce GRChombo, a new numerical relativity code written to take full advantage of modern parallel computing techniques. GRChombo's features include full adaptive mesh refinement with block structured Berger-Rigoutsos grid generation which supports non-trivial "many-boxes-in-many-boxes" meshing hierarchies, and massive parallelism through the Message Passing Interface (MPI). GRChombo evolves the Einstein equation with the standard BSSN formalism, with an option to turn on CCZ4 constraint damping if required. We show that GRChombo passes all the standard "Apples-to-Apples" code comparison tests. We also show that it can stably and accurately evolve vacuum black hole spacetimes such as binary black hole mergers, and non-vacuum spacetimes such as scalar collapses into black holes. As an illustration of its AMR capability, we demonstrate the evolution of triple black hole merger, which can be set up trivially in GRChombo.
GRChombo : Numerical Relativity with Adaptive Mesh Refinement
Clough, Katy; Finkel, Hal; Kunesch, Markus; Lim, Eugene A; Tunyasuvunakool, Saran
2015-01-01T23:59:59.000Z
Numerical relativity has undergone a revolution in the past decade. With a well-understood mathematical formalism, and full control over the gauge modes, it is now entering an era in which the science can be properly explored. In this work, we introduce GRChombo, a new numerical relativity code written to take full advantage of modern parallel computing techniques. GRChombo's features include full adaptive mesh refinement with block structured Berger-Rigoutsos grid generation which supports non-trivial "many-boxes-in-many-boxes" meshing hierarchies, and massive parallelism through the Message Passing Interface (MPI). GRChombo evolves the Einstein equation with the standard BSSN formalism, with an option to turn on CCZ4 constraint damping if required. We show that GRChombo passes all the standard "Apples-to-Apples" code comparison tests. We also show that it can stably and accurately evolve vacuum black hole spacetimes such as binary black hole mergers, and non-vacuum spacetimes such as scalar collapses into b...
Adaptive mesh refinement for shocks and material interfaces
Dai, William Wenlong [Los Alamos National Laboratory
2010-01-01T23:59:59.000Z
There are three kinds of adaptive mesh refinement (AMR) in structured meshes. Block-based AMR sometimes over refines meshes. Cell-based AMR treats cells cell by cell and thus loses the advantage of the nature of structured meshes. Patch-based AMR is intended to combine advantages of block- and cell-based AMR, i.e., the nature of structured meshes and sharp regions of refinement. But, patch-based AMR has its own difficulties. For example, patch-based AMR typically cannot preserve symmetries of physics problems. In this paper, we will present an approach for a patch-based AMR for hydrodynamics simulations. The approach consists of clustering, symmetry preserving, mesh continuity, flux correction, communications, management of patches, and load balance. The special features of this patch-based AMR include symmetry preserving, efficiency of refinement across shock fronts and material interfaces, special implementation of flux correction, and patch management in parallel computing environments. To demonstrate the capability of the AMR framework, we will show both two- and three-dimensional hydrodynamics simulations with many levels of refinement.
CONSTRAINED-TRANSPORT MAGNETOHYDRODYNAMICS WITH ADAPTIVE MESH REFINEMENT IN CHARM
Miniati, Francesco [Physics Department, Wolfgang-Pauli-Strasse 27, ETH-Zuerich, CH-8093 Zuerich (Switzerland); Martin, Daniel F., E-mail: fm@phys.ethz.ch, E-mail: DFMartin@lbl.gov [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)
2011-07-01T23:59:59.000Z
We present the implementation of a three-dimensional, second-order accurate Godunov-type algorithm for magnetohydrodynamics (MHD) in the adaptive-mesh-refinement (AMR) cosmological code CHARM. The algorithm is based on the full 12-solve spatially unsplit corner-transport-upwind (CTU) scheme. The fluid quantities are cell-centered and are updated using the piecewise-parabolic method (PPM), while the magnetic field variables are face-centered and are evolved through application of the Stokes theorem on cell edges via a constrained-transport (CT) method. The so-called multidimensional MHD source terms required in the predictor step for high-order accuracy are applied in a simplified form which reduces their complexity in three dimensions without loss of accuracy or robustness. The algorithm is implemented on an AMR framework which requires specific synchronization steps across refinement levels. These include face-centered restriction and prolongation operations and a reflux-curl operation, which maintains a solenoidal magnetic field across refinement boundaries. The code is tested against a large suite of test problems, including convergence tests in smooth flows, shock-tube tests, classical two- and three-dimensional MHD tests, a three-dimensional shock-cloud interaction problem, and the formation of a cluster of galaxies in a fully cosmological context. The magnetic field divergence is shown to remain negligible throughout.
ENZO: AN ADAPTIVE MESH REFINEMENT CODE FOR ASTROPHYSICS
Bryan, Greg L.; Turk, Matthew J. [Columbia University, Department of Astronomy, New York, NY 10025 (United States); Norman, Michael L.; Bordner, James; Xu, Hao; Kritsuk, Alexei G. [CASS, University of California, San Diego, 9500 Gilman Drive La Jolla, CA 92093-0424 (United States); O'Shea, Brian W.; Smith, Britton [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Abel, Tom; Wang, Peng; Skillman, Samuel W. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Menlo Park, CA 94025 (United States); Wise, John H. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, GA (United States); Reynolds, Daniel R. [Department of Mathematics, Southern Methodist University, Box 750156, Dallas, TX 75205-0156 (United States); Collins, David C. [Department of Physics, Florida State University, Tallahassee, FL 32306 (United States); Harkness, Robert P. [NICS, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831 (United States); Kim, Ji-hoon [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Kuhlen, Michael [Theoretical Astrophysics Center, University of California Berkeley, Hearst Field Annex, Berkeley, CA 94720 (United States); Goldbaum, Nathan [Institute for Astronomy, University of Edinburgh, Edinburgh EH9 3HJ (United Kingdom); Hummels, Cameron [Department of Astronomy/Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States); Tasker, Elizabeth [Physics Department, Faculty of Science, Hokkaido University, Kita-10 Nishi 8, Kita-ku, Sapporo 060-0810 (Japan); Collaboration: Enzo Collaboration; and others
2014-04-01T23:59:59.000Z
This paper describes the open-source code Enzo, which uses block-structured adaptive mesh refinement to provide high spatial and temporal resolution for modeling astrophysical fluid flows. The code is Cartesian, can be run in one, two, and three dimensions, and supports a wide variety of physics including hydrodynamics, ideal and non-ideal magnetohydrodynamics, N-body dynamics (and, more broadly, self-gravity of fluids and particles), primordial gas chemistry, optically thin radiative cooling of primordial and metal-enriched plasmas (as well as some optically-thick cooling models), radiation transport, cosmological expansion, and models for star formation and feedback in a cosmological context. In addition to explaining the algorithms implemented, we present solutions for a wide range of test problems, demonstrate the code's parallel performance, and discuss the Enzo collaboration's code development methodology.
RAM: a Relativistic Adaptive Mesh Refinement Hydrodynamics Code
Zhang, Wei-Qun; /KIPAC, Menlo Park; MacFadyen, Andrew I.; /Princeton, Inst. Advanced Study
2005-06-06T23:59:59.000Z
The authors have developed a new computer code, RAM, to solve the conservative equations of special relativistic hydrodynamics (SRHD) using adaptive mesh refinement (AMR) on parallel computers. They have implemented a characteristic-wise, finite difference, weighted essentially non-oscillatory (WENO) scheme using the full characteristic decomposition of the SRHD equations to achieve fifth-order accuracy in space. For time integration they use the method of lines with a third-order total variation diminishing (TVD) Runge-Kutta scheme. They have also implemented fourth and fifth order Runge-Kutta time integration schemes for comparison. The implementation of AMR and parallelization is based on the FLASH code. RAM is modular and includes the capability to easily swap hydrodynamics solvers, reconstruction methods and physics modules. In addition to WENO they have implemented a finite volume module with the piecewise parabolic method (PPM) for reconstruction and the modified Marquina approximate Riemann solver to work with TVD Runge-Kutta time integration. They examine the difficulty of accurately simulating shear flows in numerical relativistic hydrodynamics codes. They show that under-resolved simulations of simple test problems with transverse velocity components produce incorrect results and demonstrate the ability of RAM to correctly solve these problems. RAM has been tested in one, two and three dimensions and in Cartesian, cylindrical and spherical coordinates. they have demonstrated fifth-order accuracy for WENO in one and two dimensions and performed detailed comparison with other schemes for which they show significantly lower convergence rates. Extensive testing is presented demonstrating the ability of RAM to address challenging open questions in relativistic astrophysics.
Thickness-based adaptive mesh refinement methods for multi-phase flow simulations with thin regions
Chen, Xiaodong [The State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Vigor, E-mail: vigor.yang@aerospace.gatech.edu [School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0150 (United States)
2014-07-15T23:59:59.000Z
In numerical simulations of multi-scale, multi-phase flows, grid refinement is required to resolve regions with small scales. A notable example is liquid-jet atomization and subsequent droplet dynamics. It is essential to characterize the detailed flow physics with variable length scales with high fidelity, in order to elucidate the underlying mechanisms. In this paper, two thickness-based mesh refinement schemes are developed based on distance- and topology-oriented criteria for thin regions with confining wall/plane of symmetry and in any situation, respectively. Both techniques are implemented in a general framework with a volume-of-fluid formulation and an adaptive-mesh-refinement capability. The distance-oriented technique compares against a critical value, the ratio of an interfacial cell size to the distance between the mass center of the cell and a reference plane. The topology-oriented technique is developed from digital topology theories to handle more general conditions. The requirement for interfacial mesh refinement can be detected swiftly, without the need of thickness information, equation solving, variable averaging or mesh repairing. The mesh refinement level increases smoothly on demand in thin regions. The schemes have been verified and validated against several benchmark cases to demonstrate their effectiveness and robustness. These include the dynamics of colliding droplets, droplet motions in a microchannel, and atomization of liquid impinging jets. Overall, the thickness-based refinement technique provides highly adaptive meshes for problems with thin regions in an efficient and fully automatic manner.
Jablonowski, Christiane
Three Dimensional Adaptive Mesh Refinement on a Spherical Shell for Atmospheric Models for Atmospheric Research 1. Introduction One of the most important advances needed in global climate models of this project is a parallel adaptive grid library, which is currently under development at the University
An adaptive mesh refinement technique for dynamics of solids
Trivedi, Abhishek
2007-01-01T23:59:59.000Z
adaptations; right: cut-off grid with a solution contour.adaptations; right: cut-off grid with a solution contour.
Conformal refinement of unstructured quadrilateral meshes
Garmella, Rao [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
We present a multilevel adaptive refinement technique for unstructured quadrilateral meshes in which the mesh is kept conformal at all times. This means that the refined mesh, like the original, is formed of only quadrilateral elements that intersect strictly along edges or at vertices, i.e., vertices of one quadrilateral element do not lie in an edge of another quadrilateral. Elements are refined using templates based on 1:3 refinement of edges. We demonstrate that by careful design of the refinement and coarsening strategy, we can maintain high quality elements in the refined mesh. We demonstrate the method on a number of examples with dynamically changing refinement regions.
Hydrodynamical adaptive mesh refinement simulations of turbulent flows - I. Substructure in a wind
Iapichino, L; Schmidt, W; Niemeyer, J C
2008-01-01T23:59:59.000Z
The problem of the resolution of turbulent flows in adaptive mesh refinement (AMR) simulations is investigated by means of 3D hydrodynamical simulations in an idealised setup, representing a moving subcluster during a merger event. AMR simulations performed with the usual refinement criteria based on local gradients of selected variables do not properly resolve the production of turbulence downstream of the cluster. Therefore we apply novel AMR criteria which are optimised to follow the evolution of a turbulent flow. We demonstrate that these criteria provide a better resolution of the flow past the subcluster, allowing us to follow the onset of the shear instability, the evolution of the turbulent wake and the subsequent back-reaction on the subcluster core morphology. We discuss some implications for the modelling of cluster cold fronts.
Hydrodynamical adaptive mesh refinement simulations of turbulent flows - I. Substructure in a wind
L. Iapichino; J. Adamek; W. Schmidt; J. C. Niemeyer
2008-07-01T23:59:59.000Z
The problem of the resolution of turbulent flows in adaptive mesh refinement (AMR) simulations is investigated by means of 3D hydrodynamical simulations in an idealised setup, representing a moving subcluster during a merger event. AMR simulations performed with the usual refinement criteria based on local gradients of selected variables do not properly resolve the production of turbulence downstream of the cluster. Therefore we apply novel AMR criteria which are optimised to follow the evolution of a turbulent flow. We demonstrate that these criteria provide a better resolution of the flow past the subcluster, allowing us to follow the onset of the shear instability, the evolution of the turbulent wake and the subsequent back-reaction on the subcluster core morphology. We discuss some implications for the modelling of cluster cold fronts.
L. Iapichino; J. C. Niemeyer
2008-07-01T23:59:59.000Z
The development of turbulent gas flows in the intra-cluster medium and in the core of a galaxy cluster is studied by means of adaptive mesh refinement (AMR) cosmological simulations. A series of six runs was performed, employing identical simulation parameters but different criteria for triggering the mesh refinement. In particular, two different AMR strategies were followed, based on the regional variability of control variables of the flow and on the overdensity of subclumps, respectively. We show that both approaches, albeit with different results, are useful to get an improved resolution of the turbulent flow in the ICM. The vorticity is used as a diagnostic for turbulence, showing that the turbulent flow is not highly volume-filling but has a large area-covering factor, in agreement with previous theoretical expectations. The measured turbulent velocity in the cluster core is larger than 200 km/s, and the level of turbulent pressure contribution to the cluster hydrostatic equilibrium is increased by using the improved AMR criteria.
A Predictive Model of Fragmentation using Adaptive Mesh Refinement and a Hierarchical Material Model
Koniges, A E; Masters, N D; Fisher, A C; Anderson, R W; Eder, D C; Benson, D; Kaiser, T B; Gunney, B T; Wang, P; Maddox, B R; Hansen, J F; Kalantar, D H; Dixit, P; Jarmakani, H; Meyers, M A
2009-03-03T23:59:59.000Z
Fragmentation is a fundamental material process that naturally spans spatial scales from microscopic to macroscopic. We developed a mathematical framework using an innovative combination of hierarchical material modeling (HMM) and adaptive mesh refinement (AMR) to connect the continuum to microstructural regimes. This framework has been implemented in a new multi-physics, multi-scale, 3D simulation code, NIF ALE-AMR. New multi-material volume fraction and interface reconstruction algorithms were developed for this new code, which is leading the world effort in hydrodynamic simulations that combine AMR with ALE (Arbitrary Lagrangian-Eulerian) techniques. The interface reconstruction algorithm is also used to produce fragments following material failure. In general, the material strength and failure models have history vector components that must be advected along with other properties of the mesh during remap stage of the ALE hydrodynamics. The fragmentation models are validated against an electromagnetically driven expanding ring experiment and dedicated laser-based fragmentation experiments conducted at the Jupiter Laser Facility. As part of the exit plan, the NIF ALE-AMR code was applied to a number of fragmentation problems of interest to the National Ignition Facility (NIF). One example shows the added benefit of multi-material ALE-AMR that relaxes the requirement that material boundaries must be along mesh boundaries.
Dynamic Implicit 3D Adaptive Mesh Refinement for Non-Equilibrium Radiation Diffusion
Philip, Bobby [ORNL] [ORNL; Wang, Zhen [ORNL] [ORNL; Berrill, Mark A [ORNL] [ORNL; Rodriguez Rodriguez, Manuel [ORNL] [ORNL; Pernice, Michael [Idaho National Laboratory (INL)] [Idaho National Laboratory (INL)
2014-01-01T23:59:59.000Z
The time dependent non-equilibrium radiation diffusion equations are important for solving the transport of energy through radiation in optically thick regimes and find applications in several fields including astrophysics and inertial confinement fusion. The associated initial boundary value problems that are encountered exhibit a wide range of scales in space and time and are extremely challenging to solve. To efficiently and accurately simulate these systems we describe our research on combining techniques that will also find use more broadly for long term time integration of nonlinear multiphysics systems: implicit time integration for efficient long term time integration of stiff multiphysics systems, local control theory based step size control to minimize the required global number of time steps while controlling accuracy, dynamic 3D adaptive mesh refinement (AMR) to minimize memory and computational costs, Jacobian Free Newton Krylov methods on AMR grids for efficient nonlinear solution, and optimal multilevel preconditioner components that provide level independent linear solver convergence.
Schaal, Kevin; Chandrashekar, Praveen; Pakmor, Rüdiger; Klingenberg, Christian; Springel, Volker
2015-01-01T23:59:59.000Z
Solving the Euler equations of ideal hydrodynamics as accurately and efficiently as possible is a key requirement in many astrophysical simulations. It is therefore important to continuously advance the numerical methods implemented in current astrophysical codes, especially also in light of evolving computer technology, which favours certain computational approaches over others. Here we introduce the new adaptive mesh refinement (AMR) code TENET, which employs a high-order Discontinuous Galerkin (DG) scheme for hydrodynamics. The Euler equations in this method are solved in a weak formulation with a polynomial basis by means of explicit Runge-Kutta time integration and Gauss-Legendre quadrature. This approach offers significant advantages over commonly employed finite volume (FV) solvers. In particular, the higher order capability renders it computationally more efficient, in the sense that the same precision can be obtained at significantly less computational cost. Also, the DG scheme inherently conserves a...
3D Adaptive Mesh Refinement Simulations of Pellet Injection in Tokamaks
R. Samtaney; S.C. Jardin; P. Colella; D.F. Martin
2003-10-20T23:59:59.000Z
We present results of Adaptive Mesh Refinement (AMR) simulations of the pellet injection process, a proven method of refueling tokamaks. AMR is a computationally efficient way to provide the resolution required to simulate realistic pellet sizes relative to device dimensions. The mathematical model comprises of single-fluid MHD equations with source terms in the continuity equation along with a pellet ablation rate model. The numerical method developed is an explicit unsplit upwinding treatment of the 8-wave formulation, coupled with a MAC projection method to enforce the solenoidal property of the magnetic field. The Chombo framework is used for AMR. The role of the E x B drift in mass redistribution during inside and outside pellet injections is emphasized.
Dynamic implicit 3D adaptive mesh refinement for non-equilibrium radiation diffusion
B. Philip; Z. Wang; M.A. Berrill; M. Birke; M. Pernice
2014-04-01T23:59:59.000Z
The time dependent non-equilibrium radiation diffusion equations are important for solving the transport of energy through radiation in optically thick regimes and find applications in several fields including astrophysics and inertial confinement fusion. The associated initial boundary value problems that are encountered often exhibit a wide range of scales in space and time and are extremely challenging to solve. To efficiently and accurately simulate these systems we describe our research on combining techniques that will also find use more broadly for long term time integration of nonlinear multi-physics systems: implicit time integration for efficient long term time integration of stiff multi-physics systems, local control theory based step size control to minimize the required global number of time steps while controlling accuracy, dynamic 3D adaptive mesh refinement (AMR) to minimize memory and computational costs, Jacobian Free Newton–Krylov methods on AMR grids for efficient nonlinear solution, and optimal multilevel preconditioner components that provide level independent solver convergence.
Multigroup radiation hydrodynamics with flux-limited diffusion and adaptive mesh refinement
González, Matthias; Commerçon, Benoît; Masson, Jacques
2015-01-01T23:59:59.000Z
Radiative transfer plays a key role in the star formation process. Due to a high computational cost, radiation-hydrodynamics simulations performed up to now have mainly been carried out in the grey approximation. In recent years, multi-frequency radiation-hydrodynamics models have started to emerge, in an attempt to better account for the large variations of opacities as a function of frequency. We wish to develop an efficient multigroup algorithm for the adaptive mesh refinement code RAMSES which is suited to heavy proto-stellar collapse calculations. Due to prohibitive timestep constraints of an explicit radiative transfer method, we constructed a time-implicit solver based on a stabilised bi-conjugate gradient algorithm, and implemented it in RAMSES under the flux-limited diffusion approximation. We present a series of tests which demonstrate the high performance of our scheme in dealing with frequency-dependent radiation-hydrodynamic flows. We also present a preliminary simulation of a three-dimensional p...
Relativistic Hydrodynamic Flows Using Spatial and Temporal Adaptive Structured Mesh Refinement
Peng Wang; Tom Abel; Weiqun Zhang
2007-12-31T23:59:59.000Z
Astrophysical relativistic flow problems require high resolution three-dimensional numerical simulations. In this paper, we describe a new parallel three-dimensional code for simulations of special relativistic hydrodynamics (SRHD) using both spatially and temporally structured adaptive mesh refinement (AMR). We used the method of lines to discretize the SRHD equations spatially and a total variation diminishing (TVD) Runge-Kutta scheme for time integration. For spatial reconstruction, we have implemented piecewise linear method (PLM), piecewise parabolic method (PPM), third order convex essentially non-oscillatory (CENO) and third and fifth order weighted essentially non-oscillatory (WENO) schemes. Flux is computed using either direct flux reconstruction or approximate Riemann solvers including HLL, modified Marquina flux, local Lax-Friedrichs flux formulas and HLLC. The AMR part of the code is built on top of the cosmological Eulerian AMR code {\\sl enzo}. We discuss the coupling of the AMR framework with the relativistic solvers. Via various test problems, we emphasize the importance of resolution studies in relativistic flow simulations because extremely high resolution is required especially when shear flows are present in the problem. We also present the results of two 3d simulations of astrophysical jets: AGN jets and GRB jets. Resolution study of those two cases further highlights the need of high resolutions to calculate accurately relativistic flow problems.
Rhoads, James
Thermonuclear Flashes at the University of Chicago. FLASH is a modular, adaptive mesh, parallel simulation code to thermonuclear reactions in supernovae and novae. The FLASH code was designed to study thermonuclear flashes Thermonuclear Flashes, The University of Chicago, Chicago, IL 60637 2 Center for Applied Scientific Computing
Patched based methods for adaptive mesh refinement solutions of partial differential equations
Saltzman, J.
1997-09-02T23:59:59.000Z
This manuscript contains the lecture notes for a course taught from July 7th through July 11th at the 1997 Numerical Analysis Summer School sponsored by C.E.A., I.N.R.I.A., and E.D.F. The subject area was chosen to support the general theme of that year`s school which is ``Multiscale Methods and Wavelets in Numerical Simulation.`` The first topic covered in these notes is a description of the problem domain. This coverage is limited to classical PDEs with a heavier emphasis on hyperbolic systems and constrained hyperbolic systems. The next topic is difference schemes. These schemes are the foundation for the adaptive methods. After the background material is covered, attention is focused on a simple patched based adaptive algorithm and its associated data structures for square grids and hyperbolic conservation laws. Embellishments include curvilinear meshes, embedded boundary and overset meshes. Next, several strategies for parallel implementations are examined. The remainder of the notes contains descriptions of elliptic solutions on the mesh hierarchy, elliptically constrained flow solution methods and elliptically constrained flow solution methods with diffusion.
Ly{alpha} RADIATIVE TRANSFER IN COSMOLOGICAL SIMULATIONS USING ADAPTIVE MESH REFINEMENT
Laursen, Peter [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100, Copenhagen Oe (Denmark); Razoumov, Alexei O. [Institute for Computational Astrophysics, Department of Astronomy and Physics, Saint Mary's University, Halifax, NS, B3H3C3 (Canada); Sommer-Larsen, Jesper [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstrasse 2, D-85748 Garching (Germany)], E-mail: pela@dark-cosmology.dk, E-mail: razoumov@ap.smu.ca, E-mail: jslarsen@astro.ku.dk
2009-05-01T23:59:59.000Z
A numerical code for solving various Ly{alpha} radiative transfer (RT) problems is presented. The code is suitable for an arbitrary, three-dimensional distribution of Ly{alpha} emissivity, gas temperature, density, and velocity field. Capable of handling Ly{alpha} RT in an adaptively refined grid-based structure, it enables detailed investigation of the effects of clumpiness of the interstellar (or intergalactic) medium. The code is tested against various geometrically and physically idealized configurations for which analytical solutions exist, and subsequently applied to three different simulated high-resolution 'Lyman-break galaxies', extracted from high-resolution cosmological simulations at redshift z = 3.6. Proper treatment of the Ly{alpha} scattering reveals a diversity of surface brightness (SB) and line profiles. Specifically, for a given galaxy the maximum observed SB can vary by an order of magnitude, and the total flux by a factor of 3-6, depending on the viewing angle. This may provide an explanation for differences in observed properties of high-redshift galaxies, and in particular a possible physical link between Lyman-break galaxies and regular Ly{alpha} emitters.
Constrained-Transport Magnetohydrodynamics with Adaptive-Mesh-Refinement in CHARM
Miniatii, Francesco; Martin, Daniel
2011-05-24T23:59:59.000Z
We present the implementation of a three-dimensional, second order accurate Godunov-type algorithm for magneto-hydrodynamic (MHD), in the adaptivemesh-refinement (AMR) cosmological code CHARM. The algorithm is based on the full 12-solve spatially unsplit Corner-Transport-Upwind (CTU) scheme. Thefluid quantities are cell-centered and are updated using the Piecewise-Parabolic- Method (PPM), while the magnetic field variables are face-centered and areevolved through application of the Stokes theorem on cell edges via a Constrained- Transport (CT) method. The so-called ?multidimensional MHD source terms?required in the predictor step for high-order accuracy are applied in a simplified form which reduces their complexity in three dimensions without loss of accuracyor robustness. The algorithm is implemented on an AMR framework which requires specific synchronization steps across refinement levels. These includeface-centered restriction and prolongation operations and a reflux-curl operation, which maintains a solenoidal magnetic field across refinement boundaries. Thecode is tested against a large suite of test problems, including convergence tests in smooth flows, shock-tube tests, classical two- and three-dimensional MHD tests,a three-dimensional shock-cloud interaction problem and the formation of a cluster of galaxies in a fully cosmological context. The magnetic field divergence isshown to remain negligible throughout. Subject headings: cosmology: theory - methods: numerical
Schmidt, W; Iapichino, L; Vazza, F; Almgren, A S
2014-01-01T23:59:59.000Z
We compare two different codes for simulations of cosmological structure formation to investigate the sensitivity of hydrodynamical instabilities to numerics, in particular, the hydro solver and the application of adaptive mesh refinement (AMR). As a simple test problem, we consider an initially spherical gas cloud in a wind, which is an idealized model for the merger of a subcluster or galaxy with a big cluster. Based on an entropy criterion, we calculate the mass stripping from the subcluster as a function of time. Moreover, the turbulent velocity field is analyzed with a multi-scale filtering technique. We find remarkable differences between the commonly used PPM solver with directional splitting in the Enzo code and an unsplit variant of PPM in the Nyx code, which demonstrates that different codes can converge to systematically different solutions even when using uniform grids. For the test case of an unbound cloud, AMR simulations reproduce uniform-grid results for the mass stripping quite well, although...
Paris-Sud XI, Université de
of diffusive fluxes. Numerical results on an example of real-life thermal oil-recovery in a reservoir refinement, compositional Darcy flow, thermal flow, finite volume method 1 Introduction The thermal under a non-isothermal condition. The governing equations are the conservation of the amount of each
Adaptively refined large eddy simulations of clusters
Maier, A; Schmidt, W; Niemeyer, J C
2009-01-01T23:59:59.000Z
We present a numerical scheme for modelling unresolved turbulence in cosmological adaptive mesh refinement codes. As a first application, we study the evolution of turbulence in the intra-cluster medium and in the core of a galaxy cluster. Simulations with and without subgrid scale model are compared in detail. Since the flow in the ICM is subsonic, the global turbulent energy contribution at the unresolved length scales is smaller than 1% of the internal energy. We find that the production of turbulence is closely correlated with merger events occurring in the cluster environment, and its dissipation locally affects the cluster energy budget. Because of this additional source of dissipation, the core temperature is larger and the density is smaller in the presence of subgrid scale turbulence than in the standard adiabatic run, resulting in a higher entropy core value.
An accuracy study of mesh refinement on mapped grids
Calhoun, Donna
An accuracy study of mesh refinement on mapped grids D. Calhoun and R. J. LeVeque, October, 2003 on a highly skewed portion of a mapped grid. Smooth and shock-wave solutions to the Euler equations are used interface. Key words: gas dynamics, finite-volume, finite-difference, Cartesian grid, mapped grids
Visualization of Adaptive Mesh Refinement Data
Geddes, Cameron Guy Robinson
of processed data Ideal basis for specialized AMR visualization tool replacement [Argon bubble subjected: Â Create new variables from existing ones via arithmetic expressions: +, -, *, /, dot product, cross
CLAMR (Compute Language Adaptive Mesh Refinement)
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t z C o . C l a r k C o'IUHopper3CHOS2,2,CIMEL2
Stochastic domain decomposition for time dependent adaptive mesh generation
Bihlo, Alexander; Walsh, Emily J
2015-01-01T23:59:59.000Z
The efficient generation of meshes is an important component in the numerical solution of problems in physics and engineering. Of interest are situations where global mesh quality and a tight coupling to the solution of the physical partial differential equation (PDE) is important. We consider parabolic PDE mesh generation and present a method for the construction of adaptive meshes in two spatial dimensions using stochastic domain decomposition that is suitable for an implementation in a multi- or many-core environment. Methods for mesh generation on periodic domains are also provided. The mesh generator is coupled to a time dependent physical PDE and the system is evolved using an alternating solution procedure. The method uses the stochastic representation of the exact solution of a parabolic linear mesh generator to find the location of an adaptive mesh along the (artificial) subdomain interfaces. The deterministic evaluation of the mesh over each subdomain can then be obtained completely independently us...
How Efficient are Delaunay Refined Meshes? An Empirical Study
Könemann, Jochen
and the coefficients of a piecewise linear approximation, f(pl) (x, y) f(x, y). Unstructured meshes pose an efficiency-computational
Cosmos++: Relativistic Magnetohydrodynamics on Unstructured Grids with Local Adaptive Refinement
Peter Anninos; P. Chris Fragile; Jay D. Salmonson
2005-09-09T23:59:59.000Z
A new code and methodology are introduced for solving the general relativistic magnetohydrodynamic (GRMHD) equations in fixed background spacetimes using time-explicit, finite-volume discretization. The code has options for solving the GRMHD equations using traditional artificial-viscosity (AV) or non-oscillatory central difference (NOCD) methods, or a new extended AV (eAV) scheme using artificial-viscosity together with a dual energy-flux-conserving formulation. The dual energy approach allows for accurate modeling of highly relativistic flows at boost factors well beyond what has been achieved to date by standard artificial viscosity methods. It provides the benefit of Godunov methods in capturing high Lorentz boosted flows but without complicated Riemann solvers, and the advantages of traditional artificial viscosity methods in their speed and flexibility. Additionally, the GRMHD equations are solved on an unstructured grid that supports local adaptive mesh refinement using a fully threaded oct-tree (in three dimensions) network to traverse the grid hierarchy across levels and immediate neighbors. A number of tests are presented to demonstrate robustness of the numerical algorithms and adaptive mesh framework over a wide spectrum of problems, boosts, and astrophysical applications, including relativistic shock tubes, shock collisions, magnetosonic shocks, Alfven wave propagation, blast waves, magnetized Bondi flow, and the magneto-rotational instability in Kerr black hole spacetimes.
Parallel Implementation and Scaling of an Adaptive Mesh Discrete Ordinates Algorithm for Transport
Howell, L H
2004-11-29T23:59:59.000Z
Block-structured adaptive mesh refinement (AMR) uses a mesh structure built up out of locally-uniform rectangular grids. In the BoxLib parallel framework used by the Raptor code, each processor operates on one or more of these grids at each refinement level. The decomposition of the mesh into grids and the distribution of these grids among processors may change every few timesteps as a calculation proceeds. Finer grids use smaller timesteps than coarser grids, requiring additional work to keep the system synchronized and ensure conservation between different refinement levels. In a paper for NECDC 2002 I presented preliminary results on implementation of parallel transport sweeps on the AMR mesh, conjugate gradient acceleration, accuracy of the AMR solution, and scalar speedup of the AMR algorithm compared to a uniform fully-refined mesh. This paper continues with a more in-depth examination of the parallel scaling properties of the scheme, both in single-level and multi-level calculations. Both sweeping and setup costs are considered. The algorithm scales with acceptable performance to several hundred processors. Trends suggest, however, that this is the limit for efficient calculations with traditional transport sweeps, and that modifications to the sweep algorithm will be increasingly needed as job sizes in the thousands of processors become common.
Particle Systems for Adaptive, Isotropic Meshing of CAD Models
Utah, University of
Particle Systems for Adaptive, Isotropic Meshing of CAD Models Jonathan R. Bronson, Joshua A adaptive triangular surface and tetrahedral volume meshes from CAD models. Input shapes are treated. These particles reach a good distribution by minimizing an energy computed in 3D world space, with movements
Unsteady adjoint analysis for output sensitivity and mesh adaptation
Krakos, Joshua Ambre
2012-01-01T23:59:59.000Z
Adjoint analysis in computational fluid dynamics (CFD) has been applied to design optimization and mesh adaptation, but due to the relative expense of unsteady analysis these applications have predominantly been for steady ...
Dimensional reduction as a tool for mesh refinement and trackingsingularities of PDEs
Stinis, Panagiotis
2007-06-10T23:59:59.000Z
We present a collection of algorithms which utilizedimensional reduction to perform mesh refinement and study possiblysingular solutions of time-dependent partial differential equations. Thealgorithms are inspired by constructions used in statistical mechanics toevaluate the properties of a system near a critical point. The firstalgorithm allows the accurate determination of the time of occurrence ofa possible singularity. The second algorithm is an adaptive meshrefinement scheme which can be used to approach efficiently the possiblesingularity. Finally, the third algorithm uses the second algorithm untilthe available resolution is exhausted (as we approach the possiblesingularity) and then switches to a dimensionally reduced model which,when accurate, can follow faithfully the solution beyond the time ofoccurrence of the purported singularity. An accurate dimensionallyreduced model should dissipate energy at the right rate. We construct twovariants of each algorithm. The first variant assumes that we have actualknowledge of the reduced model. The second variant assumes that we knowthe form of the reduced model, i.e., the terms appearing in the reducedmodel, but not necessarily their coefficients. In this case, we alsoprovide a way of determining the coefficients. We present numericalresults for the Burgers equation with zero and nonzero viscosity toillustrate the use of the algorithms.
AN ADAPTIVE SURFACE FINITE ELEMENT METHOD BASED ON VOLUME MESHES
Demlow, Alan
studied in this paper. The paper of Dziuk [12] contains the first analysis of a finite element methodAN ADAPTIVE SURFACE FINITE ELEMENT METHOD BASED ON VOLUME MESHES ALAN DEMLOW AND MAXIM A. OLSHANSKII Abstract. In this paper we define an adaptive version of a recently introduced finite element
Yaqi Wang; Jean C. Ragusa
2011-10-01T23:59:59.000Z
Diffusion synthetic acceleration (DSA) schemes compatible with adaptive mesh refinement (AMR) grids are derived for the SN transport equations discretized using high-order discontinuous finite elements. These schemes are directly obtained from the discretized transport equations by assuming a linear dependence in angle of the angular flux along with an exact Fick's law and, therefore, are categorized as partially consistent. These schemes are akin to the symmetric interior penalty technique applied to elliptic problems and are all based on a second-order discontinuous finite element discretization of a diffusion equation (as opposed to a mixed or P1 formulation). Therefore, they only have the scalar flux as unknowns. A Fourier analysis has been carried out to determine the convergence properties of the three proposed DSA schemes for various cell optical thicknesses and aspect ratios. Out of the three DSA schemes derived, the modified interior penalty (MIP) scheme is stable and effective for realistic problems, even with distorted elements, but loses effectiveness for some highly heterogeneous configurations. The MIP scheme is also symmetric positive definite and can be solved efficiently with a preconditioned conjugate gradient method. Its implementation in an AMR SN transport code has been performed for both source iteration and GMRes-based transport solves, with polynomial orders up to 4. Numerical results are provided and show good agreement with the Fourier analysis results. Results on AMR grids demonstrate that the cost of DSA can be kept low on locally refined meshes.
Adaptive upscaling with the dual mesh method
Guerillot, D.; Verdiere, S.
1997-08-01T23:59:59.000Z
The objective of this paper is to demonstrate that upscaling should be calculated during the flow simulation instead of trying to enhance the a priori upscaling methods. Hence, counter-examples are given to motivate our approach, the so-called Dual Mesh Method. The main steps of this numerical algorithm are recalled. Applications illustrate the necessity to consider different average relative permeability values depending on the direction in space. Moreover, these values could be different for the same average saturation. This proves that an a priori upscaling cannot be the answer even in homogeneous cases because of the {open_quotes}dynamical heterogeneity{close_quotes} created by the saturation profile. Other examples show the efficiency of the Dual Mesh Method applied to heterogeneous medium and to an actual field case in South America.
Numerical relativity simulations of neutron star merger remnants using conservative mesh refinement
Tim Dietrich; Sebastiano Bernuzzi; Maximiliano Ujevic; Bernd Bruegmann
2015-04-06T23:59:59.000Z
We study equal and unequal-mass neutron star mergers by means of new numerical relativity simulations in which the general relativistic hydrodynamics solver employs an algorithm that guarantees mass conservation across the refinement levels of the computational mesh. We consider eight binary configurations with total mass $M=2.7\\,M_\\odot$, mass-ratios $q=1$ and $q=1.16$, and four different equation of states (EOSs), and one configuration with a stiff EOS, $M=2.5M_\\odot$ and $q=1.5$. We focus on the post-merger dynamics and study the merger remnant, dynamical ejecta and the postmerger gravitational wave spectrum. Although most of the merger remnants form a hypermassive neutron star collapsing to a black hole+disk system on dynamical timescales, stiff EOSs can eventually produce a stable massive neutron star. Ejecta are mostly emitted around the orbital plane; favored by large mass ratios and softer EOS. The postmerger wave spectrum is mainly characterized by non-axisymmetric oscillations of the remnant. The stiff EOS configuration consisting of a $1.5M_\\odot$ and a $1.0M_\\odot$ neutron star shows a rather peculiar dynamics. During merger the companion star is very deformed; about~$\\sim0.03M_\\odot$ of rest-mass becomes unbound from the tidal tail due torque; and the merger remnant forms stable neutron star surrounded by a massive accretion disk $\\sim0.3M_\\odot$. Similar configurations might be particularly interesting for electromagnetic counterparts. Comparing results obtained with and without the conservative mesh refinement algorithm, we find that post-merger simulations can be affected by systematic errors if mass conservation is not enforced in the mesh refinement strategy. However, mass conservation also depends on grid details and on the artificial atmosphere setup. [abridged
ROAMing terrain (Real-time Optimally Adapting Meshes)
Duchaineau, M.; Wolinsky, M.; Sigeti, D.E.; Miller, M.C.; Aldrich, C.; Mineev, M.
1997-07-01T23:59:59.000Z
Terrain visualization is a difficult problem for applications requiring accurate images of large datasets at high frame rates, such as flight simulation and ground-based aircraft testing using synthetic sensor stimulation. On current graphics hardware, the problem is to maintain dynamic, view-dependent triangle meshes and texture maps that produce good images at the required frame rate. We present an algorithm for constructing triangle meshes that optimizes flexible view-dependent error metrics, produces guaranteed error bounds, achieves specified triangle counts directly, and uses frame-to-frame coherence to operate at high frame rates for thousands of triangles per frame. Our method, dubbed Real-time Optimally Adapting Meshes (ROAM), uses two priority queues to drive split and merge operations that maintain continuous triangulations built from pre-processed bintree triangles. We introduce two additional performance optimizations: incremental triangle stripping and priority-computation deferral lists. ROAM execution time is proportionate to the number of triangle changes per frame, which is typically a few percent of the output mesh size, hence ROAM performance is insensitive to the resolution and extent of the input terrain. Dynamic terrain and simple vertex morphing are supported.
ADAPTIVE MESH REFINEMENT FOR WAVE PROPAGATION IN NONLINEAR SOLIDS
Trangenstein, John A.
Laboratory under contract W-7405-Eng-48. Partial support was* * provided by the Applied Mathematical
An adaptive mesh refinement technique for dynamics of solids
Trivedi, Abhishek
2007-01-01T23:59:59.000Z
which supports the Burger-Olinger algorithm for parallelmethod based on the Burger-Olinger algorithm [DAGH web site
Hierarchical Partitioning Techniques for Structured Adaptive Mesh Refinement Applications
(CAREERS), EIA 0103674 (NGS) and EIA-0120934 (ITR), and by DOE ASCI/ASAP (Caltech) via grant number PC
Star formation with adaptive mesh refinement and magnetohydrodynamics
Collins, David C.
2009-01-01T23:59:59.000Z
Terms . . . . 29 2.1.10 Dual Energy Formalism . . . . . . .we will discuss the dual energy formulation in Enzo forenergy shows up. With dual energy formalism on (see section
adaptive interactive technologies: Topics by E-print Network
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Shock-induced combustion Fluid-structure interaction Implementation Parallel Adaptive Cartesian Upwind Mathematics Websites Summary: Finite volume methods Adaptive mesh refinement...
hp-mesh adaptation for 1-D multigroup neutron diffusion problems
Wang, Yaqi
2007-04-25T23:59:59.000Z
-refinement.................................................................90 Fig. III-13. Convergence of different schemes.......................................................................91 Fig. III-14. Convergence results of Lobatto and Peano shape functions................................92 Fig. III-15.... Convergence results with different maximum polynomial order ........................92 Fig. III-16. Influence on convergence sequence of h-constraint and initial mesh..................94 Fig. III-17. Influence on resulting mesh of h-constraint and initial...
Adaptive Anisotropic Mesh Technique For Coupled Problems: Application To Welding Simulation
Paris-Sud XI, Université de
Adaptive Anisotropic Mesh Technique For Coupled Problems: Application To Welding Simulation M, such as welding for instance, is the control of the mesh, that is an appropriate mastering of the spatial welding. We demonstrate that the use of an anisotropic adaptive finite element method can result
Desbrun, Mathieu
tetrahedral meshes: these versatile geometric representations are used in finite element and finite volume simulations of physical phenomena as varied as material deformation, heat transfer, and electromagnetic the domain and its boundaries, while satisfying a series of criteria on element shapes and sizes. Most
ADAPTIVE PHYSICS BASED TETRAHEDRAL MESH GENERATION USING LEVEL SETS
Fedkiw, Ron
using finite elements, masses and springs, or an optimization procedure. The resulting mesh is well boundary. To maintain element quality during this compression phase we relax the positions of the nodes and as a result we obtain most if not all data from an actual human subject. Our current method involves using
A refined volume-of-fluid algorithm for capturing sharp fluid interfaces on arbitrary meshes
Zhang, Di; Jiang, Chunbo; Liang, Dongfang; Chen, Zhengbing; Yang, Yan; Shi, Ying
2014-06-30T23:59:59.000Z
conserve mass, and can be easily extended to unstructured meshes and three dimensions, so they are capable of accurately capturing the free surface and modelling merging and fragmentation in multiphase flows. In this article, a new blended high... -tracking method for the computations of multiphase flow. Journal of Computational Physics 2001; 169(2): 708–759. 21 14. Harlow FH, Welch JE. Numerical calculation of time-dependent viscous incompressible flow of fluid with free surface. Physics of Fluids...
Adaptive mesh, finite volume modeling of marine ice sheets Stephen L. Cornforda
Adaptive mesh, finite volume modeling of marine ice sheets Stephen L. Cornforda , Daniel F. Martinb Abstract Continental scale marine ice sheets such as the present day West Antarctic Ice Sheet are strongly phenomenon of this kind is the migration of the grounding line -- the division between ice in contact
Bajc, Iztok; Žumer, Slobodan
2015-01-01T23:59:59.000Z
This paper presents a 3D mesh adaptivity strategy on unstructured tetrahedral meshes by a posteriori error estimates based on metrics, studied on the case of a nonlinear finite element minimization scheme for the Landau-de Gennes free energy functional of nematic liquid crystals. Newton's iteration for tensor fields is employed with steepest descent method possibly stepping in. Aspects relating the driving of mesh adaptivity within the nonlinear scheme are considered. The algorithmic performance is found to depend on at least two factors: when to trigger each single mesh adaptation, and the precision of the correlated remeshing. Each factor is represented by a parameter, with its values possibly varying for every new mesh adaptation. We empirically show that the time of the overall algorithm convergence can vary considerably when different sequences of parameters are used, thus posing a question about optimality. The extensive testings and debugging done within this work on the simulation of systems of nemati...
Refinement trajectory and determination of eigenstates by a wavelet based adaptive method
Pipek, Janos; Nagy, Szilvia [Department of Theoretical Physics, Institute of Physics, Budapest University of Technology and Economics, H-1521 Budapest (Hungary); Department of Telecommunication, Jedlik Anyos Institute of Informatics, Electrical and Mechanical Engineering, Szechenyi Istvan University, H-9026 Gyor, Egyetem ter 1 (Hungary)
2006-11-07T23:59:59.000Z
The detail structure of the wave function is analyzed at various refinement levels using the methods of wavelet analysis. The eigenvalue problem of a model system is solved in granular Hilbert spaces, and the trajectory of the eigenstates is traced in terms of the resolution. An adaptive method is developed for identifying the fine structure localization regions, where further refinement of the wave function is necessary.
Designing for Heterogeneity and Unreliability: Examples from Adaptive Mesh
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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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisitingContract Management FermiDavid Turner David3Depth ProfilefromRefinement |
Gutowski, William J.; Prusa, Joseph M.; Smolarkiewicz, Piotr K.
2012-05-08T23:59:59.000Z
This project had goals of advancing the performance capabilities of the numerical general circulation model EULAG and using it to produce a fully operational atmospheric global climate model (AGCM) that can employ either static or dynamic grid stretching for targeted phenomena. The resulting AGCM combined EULAG's advanced dynamics core with the "physics" of the NCAR Community Atmospheric Model (CAM). Effort discussed below shows how we improved model performance and tested both EULAG and the coupled CAM-EULAG in several ways to demonstrate the grid stretching and ability to simulate very well a wide range of scales, that is, multi-scale capability. We leveraged our effort through interaction with an international EULAG community that has collectively developed new features and applications of EULAG, which we exploited for our own work summarized here. Overall, the work contributed to over 40 peer-reviewed publications and over 70 conference/workshop/seminar presentations, many of them invited. 3a. EULAG Advances EULAG is a non-hydrostatic, parallel computational model for all-scale geophysical flows. EULAG's name derives from its two computational options: EULerian (flux form) or semi-LAGrangian (advective form). The model combines nonoscillatory forward-in-time (NFT) numerical algorithms with a robust elliptic Krylov solver. A signature feature of EULAG is that it is formulated in generalized time-dependent curvilinear coordinates. In particular, this enables grid adaptivity. In total, these features give EULAG novel advantages over many existing dynamical cores. For EULAG itself, numerical advances included refining boundary conditions and filters for optimizing model performance in polar regions. We also added flexibility to the model's underlying formulation, allowing it to work with the pseudo-compressible equation set of Durran in addition to EULAG's standard anelastic formulation. Work in collaboration with others also extended the demonstrated range of validity of soundproof models, showing that they are more broadly applicable than some had previously thought. Substantial testing of EULAG included application and extension of the Jablonowski-Williamson baroclinic wave test - an archetype of planetary weather - and further analysis of multi-scale interactions arising from collapse of temperature fronts in both the baroclinic wave test and simulations of the Held-Suarez idealized climate. These analyses revealed properties of atmospheric gravity waves not seen in previous work and further demonstrated the ability of EULAG to simulate realistic behavior over several orders of magnitude of length scales. Additional collaborative work enhanced capability for modeling atmospheric flows with adaptive moving meshes and demonstrated the ability of EULAG to move into petascale computing. 3b. CAM-EULAG Advances We have developed CAM-EULAG in collaboration with former project postdoc, now University of Cape Town Assistant Professor, Babatunde Abiodun. Initial study documented good model performance in aqua-planet simulations. In particular, we showed that the grid adaptivity (stretching) implemented in CAM-EULAG allows higher resolution in selected regions without causing anomalous behavior such as spurious wave reflection. We then used the stretched-grid version to analyze simulated extreme precipitation events in West Africa, comparing the precipitation and event environment with observed behavior. The model simulates fairly well the spatial scale and the interannual and intraseasonal variability of the extreme events, although its extreme precipitation intensity is weaker than observed. In addition, both observations and the simulations show possible forcing of extreme events by African easterly waves. 3c. Other Contributions Through our collaborations, we have made contributions to a wide range of outcomes. For research focused on terrestrial behavior, these have included (1) upwind schemes for gas dynamics, (2) a nonlinear perspective on the dynamics of the Madden-Julian Oscillation, (3) numerical realism of thermal co
Iztok Bajc; Frédéric Hecht; Slobodan Žumer
2015-05-26T23:59:59.000Z
This paper presents a 3D mesh adaptivity strategy on unstructured tetrahedral meshes by a posteriori error estimates based on metrics, studied on the case of a nonlinear finite element minimization scheme for the Landau-de Gennes free energy functional of nematic liquid crystals. Newton's iteration for tensor fields is employed with steepest descent method possibly stepping in. Aspects relating the driving of mesh adaptivity within the nonlinear scheme are considered. The algorithmic performance is found to depend on at least two factors: when to trigger each single mesh adaptation, and the precision of the correlated remeshing. Each factor is represented by a parameter, with its values possibly varying for every new mesh adaptation. We empirically show that the time of the overall algorithm convergence can vary considerably when different sequences of parameters are used, thus posing a question about optimality. The extensive testings and debugging done within this work on the simulation of systems of nematic colloids substantially contributed to the upgrade of an open source finite element-oriented programming language to its 3D meshing possibilities, as also to an outer 3D remeshing module.
6th International Meshing Roundtable '97
White, D.
1997-09-01T23:59:59.000Z
The goal of the 6th International Meshing Roundtable is to bring together researchers and developers from industry, academia, and government labs in a stimulating, open environment for the exchange of technical information related to the meshing process. In the pas~ the Roundtable has enjoyed significant participation born each of these groups from a wide variety of countries. The Roundtable will consist of technical presentations from contributed papers and abstracts, two invited speakers, and two invited panels of experts discussing topics related to the development and use of automatic mesh generation tools. In addition, this year we will feature a "Bring Your Best Mesh" competition and poster session to encourage discussion and participation from a wide variety of mesh generation tool users. The schedule and evening social events are designed to provide numerous opportunities for informal dialog. A proceedings will be published by Sandia National Laboratories and distributed at the Roundtable. In addition, papers of exceptionally high quaIity will be submitted to a special issue of the International Journal of Computational Geometry and Applications. Papers and one page abstracts were sought that present original results on the meshing process. Potential topics include but are got limited to: Unstructured triangular and tetrahedral mesh generation Unstructured quadrilateral and hexahedral mesh generation Automated blocking and structured mesh generation Mixed element meshing Surface mesh generation Geometry decomposition and clean-up techniques Geometry modification techniques related to meshing Adaptive mesh refinement and mesh quality control Mesh visualization Special purpose meshing algorithms for particular applications Theoretical or novel ideas with practical potential Technical presentations from industrial researchers.
Adaptive mesh refinement for a finite difference scheme using a quadtree decomposition approach
Auviur Srinivasa, Nandagopalan
2009-05-15T23:59:59.000Z
.............................................................. 24 3.7 A Quintessential Problem in Solid Mechanics................................................ 29 IV THE TORSION PROBLEM................................................................................. 30 4.1 Introduction to the Torsion... Problem in Elasticity........................................... 30 4.2 Torsion of Cylinders of Non Circular Cross Section...................................... 35 4.3 Multiply Connected Domains...
GeoClaw's Adaptive Mesh Refinement with Dry States and Well Balancing
Maryland at College Park, University of
, Oct. 22, 2010 #12;Malpasset Dam Failure Catastrophic failure in 1959 R. J. LeVeque Coastal Flows Workshop, CSCAMM, Oct. 22, 2010 #12;Malpasset Dam Failure R. J. LeVeque Coastal Flows Workshop, CSCAMM, Oct
SOLUTION OF EQUILIBRIUM RADIATION DIFFUSION PROBLEMS USING IMPLICIT ADAPTIVE MESH REFINEMENT
Kurien, Susan
, and combustion applications such as modeling of coal-fired power generation systems and wildfire spread
Constrained-Transport Magnetohydrodynamics with Adaptive-Mesh-Refinement in CHARM
Miniatii, Francesco
2012-01-01T23:59:59.000Z
uses a piecewise-linear (PLM) or piecewise-parabolic (PPM)we illustrate the case of PLM reconstruction. So in thiso? and both in the PPM and PLM cases, and the summation is
Grauer, Rainer
of introducing coordinate transformations such that inside a small box the numeri cal resolution is sufficient. The growth of vorticity fits a power law behavior proportional to 1=(T \\Lambda \\Gamma t) where T \\Lambda
Adaptive Mesh Refinement and Multilevel Iteration for Flow in Porous Media
Trangenstein, John A.
are provided. #12; 1 Introduction. The numerical treatment of fieldscale simulation of enhanced oil recovery in diameter and involve hundreds of wells. Also, fluid models used in enhanced oil recovery often encompass tion is a formidable task. To provide useful information for the development of recovery processes
Geddes, Cameron Guy Robinson
Platforms Michael Welcome, Charles Rendleman, Leonid Oliker Computational Research Division Lawrence. It is therefore imperative to understand the tradeoffs between conventional scalar and parallel-vector platforms
adaptive tree code: Topics by E-print Network
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9 A fast tree-based method for estimating column densities in Adaptive Mesh Refinement codes Influence of UV radiation field on the structure of molecular clouds CERN Preprints...
Sudarshan, Raghunathan, 1978-
2005-01-01T23:59:59.000Z
We propose a simple and unified approach for a posteriori error estimation and adaptive mesh refinement in finite element analysis using multiresolution signal processing principles. Given a sequence of nested discretizations ...
Lipnikov, Konstantin [Los Alamos National Laboratory; Agouzal, Abdellatif [UNIV DE LYON; Vassilevski, Yuri [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
We present a new technology for generating meshes minimizing the interpolation and discretization errors or their gradients. The key element of this methodology is construction of a space metric from edge-based error estimates. For a mesh with N{sub h} triangles, the error is proportional to N{sub h}{sup -1} and the gradient of error is proportional to N{sub h}{sup -1/2} which are optimal asymptotics. The methodology is verified with numerical experiments.
Tip Vortex Field Resolution Using an Adaptive Dual-Mesh Computational Nathan Hariharan
Steffen, Michael
, efficiency, and power of the Helios dual- mesh paradigm is demonstrated through high fidelity solutions, and noise. The wake of the vehicles also complicates near-ground operations, from shipboard landings AMR in an unstructured Euler solver. Potsdam[3] also applied unstructured AMR to wind turbine wake
Armstrong, Jerawan C. [Los Alamos National Laboratory; Favorite, Jeffrey A. [Los Alamos National Laboratory
2012-06-20T23:59:59.000Z
The Levenberg-Marquardt (or simply Marquardt) and differential evolution (DE) optimization methods were recently applied to solve inverse transport problems. The Marquardt method is fast but convergence of the method is dependent on the initial guess. While it has been shown to work extremely well at finding an optimum independent of the initial guess, the DE method does not provide a global optimal solution in some problems. In this paper, we apply the Mesh Adaptive Direct Search (MADS) algorithm to solve the inverse problem of material interface location identification in one-dimensional spherical radiation source/shield systems, and we compare the results obtained by MADS to those obtained by Levenberg-Marquardt and DE.
and connectors. Simulating the entire three-dimensional (3D) structure of typical geometries of interest reaches-speed Printed Circuit Boards (PCB's) and packages. However, the latter are generally very complicated and have electromagnetic pulse during propagation. Since most EM energy only exists in a small region during
Ito, Atsushi
and dynamical load balancing, we use Morton ordered (Z-ordered) curve [2] which is a kind of space-filling curve fully threaded tree (FTT) data structure [1]. And we have parallelized the code, considering good load such as Hilbert curve. Generally, in particle code such as PIC, part of particle calculation occupies most
Robust and Efficient Adaptive Moving Mesh Solution of the 2-D Euler equations
Zegeling, Paul
to track individual features of the physi- cal solutions, such as shocks and emerging instabilities [2] in which the difficult choice of a user-defined adaptivity constant in the monitor function lists our conclusions. 2 The 2D Euler equations The two-dimensional Euler equations of gas dynamics
Method of modifying a volume mesh using sheet insertion
Borden, Michael J. (Albuquerque, NM); Shepherd, Jason F. (Albuquerque, NM)
2006-08-29T23:59:59.000Z
A method and machine-readable medium provide a technique to modify a hexahedral finite element volume mesh using dual generation and sheet insertion. After generating a dual of a volume stack (mesh), a predetermined algorithm may be followed to modify (refine) the volume mesh of hexahedral elements. The predetermined algorithm may include the steps of locating a sheet of hexahedral mesh elements, determining a plurality of hexahedral elements within the sheet to refine, shrinking the plurality of elements, and inserting a new sheet of hexahedral elements adjacently to modify the volume mesh. Additionally, another predetermined algorithm using mesh cutting may be followed to modify a volume mesh.
Eldred, Michael Scott; Subia, Samuel Ramirez; Neckels, David; Hopkins, Matthew Morgan; Notz, Patrick K.; Adams, Brian M.; Carnes, Brian; Wittwer, Jonathan W.; Bichon, Barron J.; Copps, Kevin D.
2006-10-01T23:59:59.000Z
This report documents the results for an FY06 ASC Algorithms Level 2 milestone combining error estimation and adaptivity, uncertainty quantification, and probabilistic design capabilities applied to the analysis and design of bistable MEMS. Through the use of error estimation and adaptive mesh refinement, solution verification can be performed in an automated and parameter-adaptive manner. The resulting uncertainty analysis and probabilistic design studies are shown to be more accurate, efficient, reliable, and convenient.
, it treats the simulation process as a "black box", since we estimate the dynamics from stochastic sam- ples on stochastic sampling. Our scheme combines normal and tangential geometric correction with refinement) and temporal coherence (i.e, it evolves in time through geo-morphing). · Stochastic Sampling: we employ
toolkit computational mesh conceptual model.
Baur, David G.; Edwards, Harold Carter; Cochran, William K.; Williams, Alan B.; Sjaardema, Gregory D.
2010-03-01T23:59:59.000Z
The Sierra Toolkit computational mesh is a software library intended to support massively parallel multi-physics computations on dynamically changing unstructured meshes. This domain of intended use is inherently complex due to distributed memory parallelism, parallel scalability, heterogeneity of physics, heterogeneous discretization of an unstructured mesh, and runtime adaptation of the mesh. Management of this inherent complexity begins with a conceptual analysis and modeling of this domain of intended use; i.e., development of a domain model. The Sierra Toolkit computational mesh software library is designed and implemented based upon this domain model. Software developers using, maintaining, or extending the Sierra Toolkit computational mesh library must be familiar with the concepts/domain model presented in this report.
Quadrilateral/hexahedral finite element mesh coarsening
Staten, Matthew L; Dewey, Mark W; Scott, Michael A; Benzley, Steven E
2012-10-16T23:59:59.000Z
A technique for coarsening a finite element mesh ("FEM") is described. This technique includes identifying a coarsening region within the FEM to be coarsened. Perimeter chords running along perimeter boundaries of the coarsening region are identified. The perimeter chords are redirected to create an adaptive chord separating the coarsening region from a remainder of the FEM. The adaptive chord runs through mesh elements residing along the perimeter boundaries of the coarsening region. The adaptive chord is then extracted to coarsen the FEM.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Obtain from refinement of calibrant (eg. LaB 6 ) Gives the initial values for the profile function (instrumental only parameters) Add screenshot for previous slide on...
Tetrahedral Mesh Generation for Deformable Bodies Neil Molino
Stanford University
, the finite element method or an optimization approach to relax the positions of both the interior refinement, finite element method, level set methods 1 Introduction Tetrahedral meshes are used in a number for fluid flow and heat transfer where the mesh is not deformed, and for small deformation solids where
Adaptive Implicit Non-Equilibrium Radiation Diffusion
Philip, Bobby [ORNL; Wang, Zhen [ORNL; Berrill, Mark A [ORNL; Rodriguez Rodriguez, Manuel [ORNL; Pernice, Michael [Idaho National Laboratory (INL)
2013-01-01T23:59:59.000Z
We describe methods for accurate and efficient long term time integra- tion of non-equilibrium radiation diffusion systems: implicit time integration for effi- cient long term time integration of stiff multiphysics systems, local control theory based step size control to minimize the required global number of time steps while control- ling accuracy, dynamic 3D adaptive mesh refinement (AMR) to minimize memory and computational costs, Jacobian Free Newton-Krylov methods on AMR grids for efficient nonlinear solution, and optimal multilevel preconditioner components that provide level independent solver convergence.
Adaptive-grid methods for time-dependent partial differential equations
Hedstrom, G.W.; Rodrique, G.H.
1981-01-01T23:59:59.000Z
This paper contains a survey of recent developments of adaptive-grid algorithms for time-dependent partial differential equations. Two lines of research are discussed. One involves the automatic selection of moving grids to follow propagating waves. The other is based on stationary grids but uses local mesh refinement in both space and time. Advantages and disadvantages of both approaches are discussed. The development of adaptive-grid schemes shows promise of greatly increasing our ability to solve problems in several spatial dimensions.
An adaptive framework for high-order, mixed-element numerical simulations
Caplan, Philip Claude Delhaye
2014-01-01T23:59:59.000Z
This work builds upon an adaptive simulation framework to allow for mixed-element meshes in two dimensions. Contributions are focused in the area of mesh generation which employs the Lk norm to produce various mesh types. ...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Fiber Mesh Diagnostic for Transverse Profile Measurements RadiaBeam Technologies October 2010 ATF User's Meeting R. Agustsson (PI), G. Andonian, A. Murokh, R. Tikhoplav Funded by...
ITP Petroleum Refining: Profile of the Petroleum Refining Industry...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Profile of the Petroleum Refining Industry in California: California Industries of the Future Program ITP Petroleum Refining: Profile of the Petroleum Refining Industry in...
ITP Petroleum Refining: Energy Bandwidth for Petroleum Refining...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Bandwidth for Petroleum Refining Processes ITP Petroleum Refining: Energy Bandwidth for Petroleum Refining Processes bandwidth.pdf More Documents & Publications ITP Petroleum...
Measuring mesh qualities and application to variational mesh adaptation
Huang, Weizhang
2005-11-01T23:59:59.000Z
? Wm,q(K),(2.3) where Pk(K) is the space of polynomials of degree no more than k, then there ex- ists a constant C = C(K, P , ?) such that, for all affine-equivalent finite elements (K,PK ,?K), |v ? ?k,Kv|Wm,q(K) ? C?(F ? K) ?1?m|det(F ?K)| 1 q |v.... For this case, condition (2.5) implies s = 0 and p > n. Taking t = 0 in (2.7) and using (2.4), we get |v ? ?k,Kv|Wm,q(K) ? C?(F ? K) ?1?m|det(F ?K)| 1 q × ? i1,...,il hi1,K , . . . , hil,K?D(i1,...,il)v?Lp(K).(2.8) For l = 1, (2.8) reduces to |v ? ?k,Kv...
ViewDependent Refinement of Progressive Meshes Hugues Hoppe
California at Berkeley, University of
to these criteria. The algorithm exploits view coherence, supports frame rate regulation, and is found to require not contribute to the image (Figure 12a). While these faces are typically culled early in the rendering pipeline
View-Dependent Refinement of Progressive Meshes Hugues Hoppe
Cohen, Michael
to these criteria. The algorithm exploits view coherence, supports frame rate regulation, and is found to require in the rendering pipeline, this processing incurs a cost. Similarly, it is often unnecessary to render faces
Energy Science and Technology Software Center (OSTI)
001825MLTPL01 Structured Adaptive Mesh Refinement Application Infrastructure https://computation.llnl.gov/casc/samrai
Progressive Compression of Volumetric Subdivision Meshes
Laney, D; Pascucci, V
2004-04-16T23:59:59.000Z
We present a progressive compression technique for volumetric subdivision meshes based on the slow growing refinement algorithm. The system is comprised of a wavelet transform followed by a progressive encoding of the resulting wavelet coefficients. We compare the efficiency of two wavelet transforms. The first transform is based on the smoothing rules used in the slow growing subdivision technique. The second transform is a generalization of lifted linear B-spline wavelets to the same multi-tier refinement structure. Direct coupling with a hierarchical coder produces progressive bit streams. Rate distortion metrics are evaluated for both wavelet transforms. We tested the practical performance of the scheme on synthetic data as well as data from laser indirect-drive fusion simulations with multiple fields per vertex. Both wavelet transforms result in high quality trade off curves and produce qualitatively good coarse representations.
Constant-mesh, multiple-shaft transmission
Rea, J.E.; Mills, D.D.; Sewell, J.S.
1992-04-21T23:59:59.000Z
This patent describes a multiple-shaft, constant-mesh transmission adapted to establish selectively a reverse torque delivery path and a forward drive torque delivery path and having a torque input means including a torque input shaft, a mainshaft aligned with the input shaft, a countershaft geared to the input shaft in spaced, parallel relationship with respect to the mainshaft, a torque output shaft joined to the mainshaft; multiple mainshaft gear elements journalled on the main airshaft, multiple cluster gear elements carried by the countershaft in meshing engagement with the mainshaft gear elements, one of the cluster gear elements being rotatably journalled on the countershaft; a reverse idle gear, a reverse gear journalled on the countershaft, the reverse idler gear being in constant mesh with the reverse gear and one of the mainshaft gear elements; first clutch means for connecting selectively the reverse gear and the countershaft; second synchronizer clutch means for connecting selectively the one of the mainshaft gear elements to the mainshaft; and third synchronizer clutch means for selectively connecting another of the mainshaft gear elements to the mainshaft; the first clutch means being a double-acting clutch with a first common axially movable clutch element adapted upon movement in one axial direction to drivably connected the reverse gear to the countershaft and adapted upon movement in the opposite axial direction to connect the one cluster gear element to the countershaft.
Mesh Puppetry: Cascading Optimization of Mesh Deformation with Inverse Kinematics
Desbrun, Mathieu
approach builds upon traditional rigging by optimizing skeleton position and vertex weights. Keywords: Mesh deformation, nonlinear optimization, inverse kinematics, geometry processing. 1 Introduction. To allow for more global and complex deforma- tion, many authors proposed to cast mesh deformation
A Unified Algorithm for Adaptive Spacetime Meshing
Thite, Shripad
: Wave equation describing displacement u(x, t) about the mean. utt - 2 uxx = 0 (i) wavespeed can terrain whose spatial projection is a triangulation Advance in time local neighborhood of front of dependence of Q. Approximate domains of dependence and influence by a circular symmetric double cone. Shripad
Bozzelli, Laura; French, Tim; Hales, James; Pinchinat, Sophie
2012-01-01T23:59:59.000Z
In this paper we present refinement modal logic. A refinement is like a bisimulation, except that from the three relational requirements only 'atoms' and 'back' need to be satisfied. Our logic contains a new operator 'forall' in additional to the standard modalities 'Box' for each agent. The operator 'forall' acts as a quantifier over the set of all refinements of a given model. We call it the refinement operator. As a variation on a bisimulation quantifier, it can be seen as a refinement quantifier over a variable not occurring in the formula bound by the operator. The logic combines the simplicity of multi-agent modal logic with some powers of monadic second order quantification. We present a sound and complete axiomatization of multiagent refinement modal logic. We also present an extension of the logic to the modal mu-calculus, and an axiomatization for the single-agent version of this logic. Examples and applications are also discussed: to software verification and design (the set of agents can also be s...
Advances in the development of wire mesh reactor for coal gasification studies - article no. 084102
Zeng, C.; Chen, L.; Liu, G.; Li, W.H.; Huang, B.M.; Zhu, H.D.; Zhang, B.; Zamansky, V. [GE Global Research Shanghai, Shanghai (China)
2008-08-15T23:59:59.000Z
In an effort to further understand the coal gasification behavior in entrained-flow gasifiers, a high pressure and high temperature wire mesh reactor with new features was recently built. An advanced LABVIEW-based temperature measurement and control system were adapted. Molybdenum wire mesh with aperture smaller than 70 {mu} m and type D thermocouple were used to enable high carbon conversion ({gt}90%) at temperatures {gt}1000 {sup o}C. Gaseous species from wire mesh reactor were quantified using a high sensitivity gas chromatography. The material balance of coal pyrolysis in wire mesh reactor was demonstrated for the first time by improving the volatile's quantification techniques.
Wood, A.; Cornitius, T.
1997-06-11T23:59:59.000Z
The U.S.Refining Industry is facing hard times. Slow growth, tough environmental regulations, and fierce competition - especially in retail gasoline - have squeezed margins and prompted a series of mergers and acquisitions. The trend has affected the smallest and largest players, and a series of transactions over the past two years has created a new industry lineup. Among the larger companies, Mobil and Amoco are the latest to consider a refining merger. That follows recent plans by Ashland and Marathon to merge their refining businesses, and the decision by Shell, Texaco, and Saudi Aramco to combine some U.S. operations. Many of the leading independent refiners have increased their scale by acquiring refinery capacity. With refining still in the doldrums, more independents are taking a closer look at boosting production of petrochemicals, which offer high growth and, usually, better margins. That is being helped by the shift to refinery processes that favor the increased production of light olefins for alkylation and the removal of aromatics, providing opportunity to extract these materials for the petrochemical market. 5 figs., 3 tabs.
Analysis of moving mesh partial differential equations with spatial smoothing
Huang, Weizhang; Russell, Robert D.
1997-06-01T23:59:59.000Z
ANALYSIS OF MOVING MESH PARTIAL DIFFERENTIAL EQUATIONS WITH SPATIAL SMOOTHING#3; WEIZHANG HUANGy AND ROBERT D. RUSSELLz SIAM J. NUMER. ANAL. c© 1997 Society for Industrial and Applied Mathematics Vol. 34, No. 3, pp. 1106{1126, June 1997 013 Abstract.... report NM-N8902, CWI, Amsterdam, 1989. [CD85] G. F. CAREY AND H. T. DINH, Grading functions and mesh redistribution, SIAM J. Numer. Anal., 22 (1985), pp. 1028{1040. [DD87] E. A. DORFI AND L. O’C. DRURY, Simple adaptive grids for 1-D initial value problems...
Towards automated crystallographic structure refinement with phenix.refine
Afonine, Pavel V., E-mail: pafonine@lbl.gov; Grosse-Kunstleve, Ralf W.; Echols, Nathaniel; Headd, Jeffrey J.; Moriarty, Nigel W. [Lawrence Berkeley National Laboratory, One Cyclotron Road, MS64R0121, Berkeley, CA 94720 (United States); Mustyakimov, Marat; Terwilliger, Thomas C. [Los Alamos National Laboratory, M888, Los Alamos, NM 87545 (United States); Urzhumtsev, Alexandre [CNRS–INSERM–UdS, 1 Rue Laurent Fries, BP 10142, 67404 Illkirch (France); Université Henri Poincaré, Nancy 1, BP 239, 54506 Vandoeuvre-lčs-Nancy (France); Zwart, Peter H. [Lawrence Berkeley National Laboratory, One Cyclotron Road, MS64R0121, Berkeley, CA 94720 (United States); Adams, Paul D. [Lawrence Berkeley National Laboratory, One Cyclotron Road, MS64R0121, Berkeley, CA 94720 (United States); University of California Berkeley, Berkeley, CA 94720 (United States)
2012-04-01T23:59:59.000Z
phenix.refine is a program within the PHENIX package that supports crystallographic structure refinement against experimental data with a wide range of upper resolution limits using a large repertoire of model parameterizations. This paper presents an overview of the major phenix.refine features, with extensive literature references for readers interested in more detailed discussions of the methods. phenix.refine is a program within the PHENIX package that supports crystallographic structure refinement against experimental data with a wide range of upper resolution limits using a large repertoire of model parameterizations. It has several automation features and is also highly flexible. Several hundred parameters enable extensive customizations for complex use cases. Multiple user-defined refinement strategies can be applied to specific parts of the model in a single refinement run. An intuitive graphical user interface is available to guide novice users and to assist advanced users in managing refinement projects. X-ray or neutron diffraction data can be used separately or jointly in refinement. phenix.refine is tightly integrated into the PHENIX suite, where it serves as a critical component in automated model building, final structure refinement, structure validation and deposition to the wwPDB. This paper presents an overview of the major phenix.refine features, with extensive literature references for readers interested in more detailed discussions of the methods.
Wavelet Analysis for Progressive Meshes Martin Bertram
Hering-Bertram, Martin
Wavelet Analysis for Progressive Meshes Martin Bertram Fraunhofer ITWM Kaiserslautern Abstract We present a wavelet construction for irregular triangle meshes based on edge-collapse and vertex: progressive meshes, wavelets, compression, multires- olution modeling 1 Introduction Wavelets provide
A Theory of Program Refinement
Denney, Ewen WKC
We give a canonical program refinement calculus based on the lambda calculus and classical first-order predicate logic, and study its proof theory and semantics. The intention is to construct a metalanguage for refinement in which basic principles...
Collaboration Topics - Meshing | National Nuclear Security Administrat...
National Nuclear Security Administration (NNSA)
Simulation and Computing and Institutional R&D Programs NNSACEA Cooperation in Computer Science Collaboration Topics - Meshing Collaboration Topics - Meshing This work...
Robust and efficient overset grid assembly for partitioned unstructured meshes
Roget, Beatrice, E-mail: broget@uwyo.edu; Sitaraman, Jayanarayanan, E-mail: jsitaram@uwyo.edu
2014-03-01T23:59:59.000Z
This paper presents a method to perform efficient and automated Overset Grid Assembly (OGA) on a system of overlapping unstructured meshes in a parallel computing environment where all meshes are partitioned into multiple mesh-blocks and processed on multiple cores. The main task of the overset grid assembler is to identify, in parallel, among all points in the overlapping mesh system, at which points the flow solution should be computed (field points), interpolated (receptor points), or ignored (hole points). Point containment search or donor search, an algorithm to efficiently determine the cell that contains a given point, is the core procedure necessary for accomplishing this task. Donor search is particularly challenging for partitioned unstructured meshes because of the complex irregular boundaries that are often created during partitioning. Another challenge arises because of the large variation in the type of mesh-block overlap and the resulting large load imbalance on multiple processors. Desirable traits for the grid assembly method are efficiency (requiring only a small fraction of the solver time), robustness (correct identification of all point types), and full automation (no user input required other than the mesh system). Additionally, the method should be scalable, which is an important challenge due to the inherent load imbalance. This paper describes a fully-automated grid assembly method, which can use two different donor search algorithms. One is based on the use of auxiliary grids and Exact Inverse Maps (EIM), and the other is based on the use of Alternating Digital Trees (ADT). The EIM method is demonstrated to be more efficient than the ADT method, while retaining robustness. An adaptive load re-balance algorithm is also designed and implemented, which considerably improves the scalability of the method.
Streaming Compression of Hexahedral Meshes
Isenburg, M; Courbet, C
2010-02-03T23:59:59.000Z
We describe a method for streaming compression of hexahedral meshes. Given an interleaved stream of vertices and hexahedral our coder incrementally compresses the mesh in the presented order. Our coder is extremely memory efficient when the input stream documents when vertices are referenced for the last time (i.e. when it contains topological finalization tags). Our coder then continuously releases and reuses data structures that no longer contribute to compressing the remainder of the stream. This means in practice that our coder has only a small fraction of the whole mesh in memory at any time. We can therefore compress very large meshes - even meshes that do not file in memory. Compared to traditional, non-streaming approaches that load the entire mesh and globally reorder it during compression, our algorithm trades a less compact compressed representation for significant gains in speed, memory, and I/O efficiency. For example, on the 456k hexahedra 'blade' mesh, our coder is twice as fast and uses 88 times less memory (only 3.1 MB) with the compressed file increasing about 3% in size. We also present the first scheme for predictive compression of properties associated with hexahedral cells.
Minimally refined biomass fuel
Pearson, Richard K. (Pleasanton, CA); Hirschfeld, Tomas B. (Livermore, CA)
1984-01-01T23:59:59.000Z
A minimally refined fluid composition, suitable as a fuel mixture and derived from biomass material, is comprised of one or more water-soluble carbohydrates such as sucrose, one or more alcohols having less than four carbons, and water. The carbohydrate provides the fuel source; water solubilizes the carbohydrates; and the alcohol aids in the combustion of the carbohydrate and reduces the vicosity of the carbohydrate/water solution. Because less energy is required to obtain the carbohydrate from the raw biomass than alcohol, an overall energy savings is realized compared to fuels employing alcohol as the primary fuel.
HEXHOOP: MODULAR TEMPLATES FOR CONVERTING A HEX-DOMINANT MESH TO AN ALL-HEX MESH
Shimada, Kenji
. Such conversion templates make all-hex meshing possible for a complicated geometry for which the existing direct conversion template, called HEXHOOP, that fully automates a conversion from a hex-dominant mesh to an all templates successfully convert a hex-dominant mesh to an all-hex mesh. Keywords: mesh conversion, template
Refines Efficiency Improvement
WRI
2002-05-15T23:59:59.000Z
Refinery processes that convert heavy oils to lighter distillate fuels require heating for distillation, hydrogen addition or carbon rejection (coking). Efficiency is limited by the formation of insoluble carbon-rich coke deposits. Heat exchangers and other refinery units must be shut down for mechanical coke removal, resulting in a significant loss of output and revenue. When a residuum is heated above the temperature at which pyrolysis occurs (340 C, 650 F), there is typically an induction period before coke formation begins (Magaril and Aksenova 1968, Wiehe 1993). To avoid fouling, refiners often stop heating a residuum before coke formation begins, using arbitrary criteria. In many cases, this heating is stopped sooner than need be, resulting in less than maximum product yield. Western Research Institute (WRI) has developed innovative Coking Index concepts (patent pending) which can be used for process control by refiners to heat residua to the threshold, but not beyond the point at which coke formation begins when petroleum residua materials are heated at pyrolysis temperatures (Schabron et al. 2001). The development of this universal predictor solves a long standing problem in petroleum refining. These Coking Indexes have great potential value in improving the efficiency of distillation processes. The Coking Indexes were found to apply to residua in a universal manner, and the theoretical basis for the indexes has been established (Schabron et al. 2001a, 2001b, 2001c). For the first time, a few simple measurements indicates how close undesired coke formation is on the coke formation induction time line. The Coking Indexes can lead to new process controls that can improve refinery distillation efficiency by several percentage points. Petroleum residua consist of an ordered continuum of solvated polar materials usually referred to as asphaltenes dispersed in a lower polarity solvent phase held together by intermediate polarity materials usually referred to as resins. The Coking Indexes focus on the amount of these intermediate polarity species since coke formation begins when these are depleted. Currently the Coking Indexes are determined by either titration or solubility measurements which must be performed in a laboratory. In the current work, various spectral, microscopic, and thermal techniques possibly leading to on-line analysis were explored for measuring the Coking Indexes.
A Concept-Driven Construction of the Mondex Protocol using Three Refinements
Banach, Richard
as closely as possible to the original, or by adapting the problem to fit the style of the tool, thereby, the proof is monolithic, consisting of a single refinement. Other authors, particularly [19] and [20], have
A ConceptDriven Construction of the Mondex Protocol using Three Refinements
Banach, Richard
as closely as possible to the original, or by adapting the problem to fit the style of the tool, thereby, the proof is monolithic, consisting of a single refinement. Other authors, particularly [19] and [20], have
Interactive graphical tools for three-dimensional mesh redistribution
Dobbs, L.A.
1996-03-01T23:59:59.000Z
Three-dimensional meshes modeling nonlinear problems such as sheet metal forming, metal forging, heat transfer during welding, the propagation of microwaves through gases, and automobile crashes require highly refined meshes in local areas to accurately represent areas of high curvature, stress, and strain. These locally refined areas develop late in the simulation and/or move during the course of the simulation, thus making it difficult to predict their exact location. This thesis is a systematic study of new tools scientists can use with redistribution algorithms to enhance the solution results and reduce the time to build, solve, and analyze nonlinear finite element problems. Participatory design techniques including Contextual Inquiry and Design were used to study and analyze the process of solving such problems. This study and analysis led to the in-depth understanding of the types of interactions performed by FEM scientists. Based on this understanding, a prototype tool was designed to support these interactions. Scientists participated in evaluating the design as well as the implementation of the prototype tool. The study, analysis, prototype tool design, and the results of the evaluation of the prototype tool are described in this thesis.
Crystal structure refinement with SHELXL
Sheldrick, George M., E-mail: gsheldr@shelx.uni-ac.gwdg.de [Department of Structural Chemistry, Georg-August Universität Göttingen, Tammannstraße 4, Göttingen 37077 (Germany)
2015-01-01T23:59:59.000Z
New features added to the refinement program SHELXL since 2008 are described and explained. The improvements in the crystal structure refinement program SHELXL have been closely coupled with the development and increasing importance of the CIF (Crystallographic Information Framework) format for validating and archiving crystal structures. An important simplification is that now only one file in CIF format (for convenience, referred to simply as ‘a CIF’) containing embedded reflection data and SHELXL instructions is needed for a complete structure archive; the program SHREDCIF can be used to extract the .hkl and .ins files required for further refinement with SHELXL. Recent developments in SHELXL facilitate refinement against neutron diffraction data, the treatment of H atoms, the determination of absolute structure, the input of partial structure factors and the refinement of twinned and disordered structures. SHELXL is available free to academics for the Windows, Linux and Mac OS X operating systems, and is particularly suitable for multiple-core processors.
Peraire, Jaime
A Simplex Cut-Cell Adaptive Method for High-Order Discretizations of the Compressible Navier;A Simplex Cut-Cell Adaptive Method for High-Order Discretizations of the Compressible Navier adaptation for high-order discretizations and simplex, cut-cell mesh generation. First, output-based mesh
Towards Real Earth Models --Computational Geophysics on Unstructured Tetrahedral Meshes?
Farquharson, Colin G.
Towards Real Earth Models -- Computational Geophysics on Unstructured Tetrahedral Meshes? Colin tetrahedral meshes. EM geophysics on unstructured tetrahedral meshes. Disadvantages, difficulties, challenges. Conclusions. #12;Outline: Geological models! Advantages of unstructured tetrahedral meshes. EM geophysics
Mesh Puppetry: Cascading Optimization of Mesh Deformation with Inverse Kinematics
Zhou, Kun
approach builds upon traditional rigging by optimizing skeleton position and vertex weights. Keywords: Mesh deformation, nonlinear optimization, inverse kinematics, geometry processing. 1 Introduction,mathieu}@caltech.edu Figure 1: Armadillo Olympics: The Armadillo model (top left) can be deformed to take various sport poses
ITP Petroleum Refining: Energy and Environmental Profile of the...
Energy Bandwidth for Petroleum Refining Processes ITP Petroleum Refining: Technology Roadmap for the Petroleum Industry ITP Petroleum Refining: Profile of the Petroleum Refining...
ORIGINAL ARTICLE Hexahedral mesh generation constraints
Utah, University of
For finite element analyses within highly elastic and plastic structural domains, hexahedral meshes have historically offered some benefits over tetrahedral finite element meshes in terms of reduced error, smaller element counts, and improved reliability. However, hexahedral finite element mesh generation continues
Zhang, Jie; Ni, Ming-Jiu, E-mail: mjni@ucas.ac.cn
2014-01-01T23:59:59.000Z
The numerical simulation of Magnetohydrodynamics (MHD) flows with complex boundaries has been a topic of great interest in the development of a fusion reactor blanket for the difficulty to accurately simulate the Hartmann layers and side layers along arbitrary geometries. An adaptive version of a consistent and conservative scheme has been developed for simulating the MHD flows. Besides, the present study forms the first attempt to apply the cut-cell approach for irregular wall-bounded MHD flows, which is more flexible and conveniently implemented under adaptive mesh refinement (AMR) technique. It employs a Volume-of-Fluid (VOF) approach to represent the fluid–conducting wall interface that makes it possible to solve the fluid–solid coupling magnetic problems, emphasizing at how electric field solver is implemented when conductivity is discontinuous in cut-cell. For the irregular cut-cells, the conservative interpolation technique is applied to calculate the Lorentz force at cell-center. On the other hand, it will be shown how consistent and conservative scheme is implemented on fine/coarse mesh boundaries when using AMR technique. Then, the applied numerical schemes are validated by five test simulations and excellent agreement was obtained for all the cases considered, simultaneously showed good consistency and conservative properties.
Mesh-based Sensor Relocation for Coverage Maintenance in Mobile Sensor Networks
Santoro, Nicola
sophisticated protocols, mobile sensor networks are more flexible and adaptive to unknown or hazardous of reasons. All of them rely on global/cross-network message transmissions for discovering nearby replacementMesh-based Sensor Relocation for Coverage Maintenance in Mobile Sensor Networks Xu Li SCS, Carleton
TetSplat: Real-Time Rendering and Volume Clipping of Large Unstructured Tetrahedral Meshes
TetSplat: Real-Time Rendering and Volume Clipping of Large Unstructured Tetrahedral Meshes Ken-resolution data representations. These compact hierarchical data structures are then adaptively rendered and probed in real-time on a commodity PC. Our point-based rendering algorithm, which is inspired by QSplat
A PARALLEL GEOMETRIC MULTIGRID METHOD FOR FINITE ELEMENTS ON OCTREE MESHES
Biros, George
A PARALLEL GEOMETRIC MULTIGRID METHOD FOR FINITE ELEMENTS ON OCTREE MESHES RAHUL S. SAMPATH for the discretized finite element operators and the intergrid transfer operations. The key component of our scheme it has a low setup cost. Key words. Geometric Multigrid, Finite Element Method, Linear Octrees, Adaptive
Zone refining of plutonium metal
Blau, M.S.
1994-08-01T23:59:59.000Z
The zone refining process was applied to Pu metal containing known amounts of impurities. Rod specimens of plutonium metal were melted into and contained in tantalum boats, each of which was passed horizontally through a three-turn, high-frequency coil in such a manner as to cause a narrow molten zone to pass through the Pu metal rod 10 times. The impurity elements Co, Cr, Fe, Ni, Np, U were found to move in the same direction as the molten zone as predicted by binary phase diagrams. The elements Al, Am, and Ga moved in the opposite direction of the molten zone as predicted by binary phase diagrams. As the impurity alloy was zone refined, {delta}-phase plutonium metal crystals were produced. The first few zone refining passes were more effective than each later pass because an oxide layer formed on the rod surface. There was no clear evidence of better impurity movement at the slower zone refining speed. Also, constant or variable coil power appeared to have no effect on impurity movement during a single run (10 passes). This experiment was the first step to developing a zone refining process for plutonium metal.
Confined helium on Lagrange meshes
Baye, Daniel
2015-01-01T23:59:59.000Z
The Lagrange-mesh method has the simplicity of a calculation on a mesh and can have the accuracy of a variational method. It is applied to the study of a confined helium atom. Two types of confinement are considered. Soft confinements by potentials are studied in perimetric coordinates. Hard confinement in impenetrable spherical cavities is studied in a system of rescaled perimetric coordinates varying in [0,1] intervals. Energies and mean values of the distances between electrons and between an electron and the helium nucleus are calculated. A high accuracy of 11 to 15 significant figures is obtained with small computing times. Pressures acting on the confined atom are also computed. For sphere radii smaller than 1, their relative accuracies are better than $10^{-10}$. For larger radii up to 10, they progressively decrease to $10^{-3}$, still improving the best literature results.
Modeling planar 3-valence meshes
Gonen, Ozgur
2009-05-15T23:59:59.000Z
Akleman Vinod Srinivasan Committee Members, Richard Burt Head of Department, Mark Clayton December 2007 Major Subject: Visualization Sciences iii ABSTRACT Modeling Planar 3-Valence Meshes. (December 2007) Ozgur Gonen, B.A., Istanbul Bilgi University Co... Istanbul Bilgi University in 2003. He worked as a Multimedia Developer before joining the Master of Science in Visualization Sciences program at Texas A&M University. He mostly worked with Dr. Ergun Akleman during his masters studies. He can be reached...
Modeling planar 3-valence meshes
Gonen, Ozgur
2008-10-10T23:59:59.000Z
Akleman Vinod Srinivasan Committee Members, Richard Burt Head of Department, Mark Clayton December 2007 Major Subject: Visualization Sciences iii ABSTRACT Modeling Planar 3-Valence Meshes. (December 2007) Ozgur Gonen, B.A., Istanbul Bilgi University Co... Istanbul Bilgi University in 2003. He worked as a Multimedia Developer before joining the Master of Science in Visualization Sciences program at Texas A&M University. He mostly worked with Dr. Ergun Akleman during his masters studies. He can be reached...
Method of generating a surface mesh
Shepherd, Jason F. (Albuquerque, NM); Benzley, Steven (Provo, UT); Grover, Benjamin T. (Tracy, CA)
2008-03-04T23:59:59.000Z
A method and machine-readable medium provide a technique to generate and modify a quadrilateral finite element surface mesh using dual creation and modification. After generating a dual of a surface (mesh), a predetermined algorithm may be followed to generate and modify a surface mesh of quadrilateral elements. The predetermined algorithm may include the steps of generating two-dimensional cell regions in dual space, determining existing nodes in primal space, generating new nodes in the dual space, and connecting nodes to form the quadrilateral elements (faces) for the generated and modifiable surface mesh.
7th International Meshing Roundtable '98
Eldred, T.J.
1998-10-01T23:59:59.000Z
The goal of the 7th International Meshing Roundtable is to bring together researchers and developers from industry, academia, and government labs in a stimulating, open environment for the exchange of technical information related to the meshing process. In the past, the Roundtable has enjoyed significant participation from each of these groups from a wide variety of countries.
ITP Petroleum Refining: Impacts of Condition Assessment on Energy...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
ITP Petroleum Refining: Impacts of Condition Assessment on Energy Use: Selected Applications in Chemicals Processing and Petroleum Refining ITP Petroleum Refining: Impacts of...
Firing of pulverized solvent refined coal
Derbidge, T. Craig (Sunnyvale, CA); Mulholland, James A. (Chapel Hill, NC); Foster, Edward P. (Macungie, PA)
1986-01-01T23:59:59.000Z
An air-purged burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired without the coking thereof on the burner components. The air-purged burner is designed for the firing of pulverized solvent refined coal in a tangentially fired boiler.
Feature recognition applications in mesh generation
Tautges, T.J. [Sandia National Labs., Albuquerque, NM (United States); Liu, S.S.; Lu, Y.; Kraftcheck, J.; Gadh, R. [Wisconsin Univ., Madison, WI (United States). Mechanical Engineering Dept.
1997-06-01T23:59:59.000Z
The use of feature recognition as part of an overall decomposition-based hexahedral meshing approach is described in this paper. The meshing approach consists of feature recognition, using a c-loop or hybrid c-loop method, and the use of cutting surfaces to decompose the solid model. These steps are part of an iterative process, which proceeds either until no more features can be recognized or until the model has been completely decomposed into meshable sub-volumes. This method can greatly reduce the time required to generate an all-hexahedral mesh, either through the use of more efficient meshing algorithms on more of the geometry or by reducing the amount of manual decomposition required to mesh a volume.
Parallel octree-based hexahedral mesh generation for eulerian to lagrangian conversion.
Staten, Matthew L.; Owen, Steven James
2010-09-01T23:59:59.000Z
Computational simulation must often be performed on domains where materials are represented as scalar quantities or volume fractions at cell centers of an octree-based grid. Common examples include bio-medical, geotechnical or shock physics calculations where interface boundaries are represented only as discrete statistical approximations. In this work, we introduce new methods for generating Lagrangian computational meshes from Eulerian-based data. We focus specifically on shock physics problems that are relevant to ASC codes such as CTH and Alegra. New procedures for generating all-hexahedral finite element meshes from volume fraction data are introduced. A new primal-contouring approach is introduced for defining a geometric domain. New methods for refinement, node smoothing, resolving non-manifold conditions and defining geometry are also introduced as well as an extension of the algorithm to handle tetrahedral meshes. We also describe new scalable MPI-based implementations of these procedures. We describe a new software module, Sculptor, which has been developed for use as an embedded component of CTH. We also describe its interface and its use within the mesh generation code, CUBIT. Several examples are shown to illustrate the capabilities of Sculptor.
adaptive mesh strategy: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
used to solve hyperbolic spacetime partial differential equations (PDEs) to accurately model wave propagation phenomena arising in important applications in science and...
Optimization Online - The mesh adaptive direct search algorithm ...
Robert B. Gramacy
2011-07-06T23:59:59.000Z
Jul 6, 2011 ... ... optima; one real application from a chemical engineering simulator for styrene production; and one from contaminant cleanup and hydrology.
The mesh adaptive direct search algorithm with treed Gaussian ...
Gramacy and Le Digabel
2013-05-24T23:59:59.000Z
May 24, 2013 ... for styrene production; and one from contaminant cleanup and hydrology. In all three cases we show that the TGP surrogate is preferable to a ...
anisotropic mesh adaptation: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
due to the large ratio ????. One goal in the plasma physics research is to control the thermonuclear fusion power by magnetic confinement... is added to reduce the poloidal...
Unstructured Adaptive Mesh MOL Solvers for Atmospheric Reacting
Utah, University of
. Achieving high resolution in air pollution models is a difficult challenge because of the large number for the next generation of air pollution models in order to "capture important smaller scale atmospheric in understanding the complex processes which lead to the formation of pollutants such as greenhouse gases, acid
Repartitioning of Adaptive Meshes: Experiments with Multilevel Di usion ?
Karypis, George
are simply swapped into one or more underbalanced partitions in order to bring these par- titions up
Dynamic scaling in the Mesh Adaptive Direct Search algorithm for ...
Audet Le Digabel Tribes
2014-03-31T23:59:59.000Z
Mar 31, 2014 ... occurs when the output of these functions are obtained by launching a computer code with some x ? Rn as input. These functions are typically ...
An Arbitrary Lagrangian Eulerian Formulation with Adaptive Mesh ...
... Lawrence Livermore National Laboratory Abstract: An efficient numerical ... of Energy by University of California Lawrence Livermore National Laboratory ...
Volume Rendering by Adaptive Refinement (revised January, 1989)
Stanford University
. 1988; Sabella 1988; Upson and Keeler 1988). The principal advantages of volume rendering over other
Triangular and Quadrilateral Surface Mesh Quality Optimization Using Local
Shashkov, Mikhail
quality solid meshes. Since surface meshes define external and internal boundaries of computational and mixed meshes in the plane [16]. However, optimization of surface meshes must address addi- tional in a locally derived tangent plane and then pull the vertex back to the smo
Zone refining of plutonium metal
NONE
1997-05-01T23:59:59.000Z
The purpose of this study was to investigate zone refining techniques for the purification of plutonium metal. The redistribution of 10 impurity elements from zone melting was examined. Four tantalum boats were loaded with plutonium impurity alloy, placed in a vacuum furnace, heated to 700{degrees}C, and held at temperature for one hour. Ten passes were made with each boat. Metallographic and chemical analyses performed on the plutonium rods showed that, after 10 passes, moderate movement of certain elements were achieved. Molten zone speeds of 1 or 2 inches per hour had no effect on impurity element movement. Likewise, the application of constant or variable power had no effect on impurity movement. The study implies that development of a zone refining process to purify plutonium is feasible. Development of a process will be hampered by two factors: (1) the effect on impurity element redistribution of the oxide layer formed on the exposed surface of the material is not understood, and (2) the tantalum container material is not inert in the presence of plutonium. Cold boat studies are planned, with higher temperature and vacuum levels, to determine the effect on these factors. 5 refs., 1 tab., 5 figs.
LR: Compact connectivity representation for triangle meshes
Gurung, T; Luffel, M; Lindstrom, P; Rossignac, J
2011-01-28T23:59:59.000Z
We propose LR (Laced Ring) - a simple data structure for representing the connectivity of manifold triangle meshes. LR provides the option to store on average either 1.08 references per triangle or 26.2 bits per triangle. Its construction, from an input mesh that supports constant-time adjacency queries, has linear space and time complexity, and involves ordering most vertices along a nearly-Hamiltonian cycle. LR is best suited for applications that process meshes with fixed connectivity, as any changes to the connectivity require the data structure to be rebuilt. We provide an implementation of the set of standard random-access, constant-time operators for traversing a mesh, and show that LR often saves both space and traversal time over competing representations.
Overhearing in 802.11 mesh networks
Afanasyev, Mikhail
2009-01-01T23:59:59.000Z
through a port on an HP 2626-PWR switch. There are sevenuplink, but no neighbors in the mesh. ) CDF of nodes Pwr5 Pwr 10 Pwr 15 Pwr 20 Pwr 30 Pwr 40 Pwr 50 Pwr 60
Hexahedral Mesh Generation Constraints Jason F. Shepherd
Utah, University of
Introduction Numerical approximation methods, including finite element, finite difference, and finite volume finite element meshes have historically offered some mathematical benefit over tetrahe- dral finite with respect to finite element analyses within highly elastic, and plastic, structural domains. However
Reaping Energy Savings from Petroleum Refining
Deng, A.; Cascone, R.
2006-01-01T23:59:59.000Z
REAPING ENERGY SAVINGS FROM PETROLEUM REFINING Alan Deng, Project Manager, San Francisco, CA, Ron Cascone, Project Manager, White Plains, NY, Nexant, Inc. ABSTRACT The refining industry is one of the largest energy users in Pacific Gas... years’ energy conservation and demand-side management program participation. The PG&E’s refinery energy efficiency program (REEP) is designed to address key market barriers and tap into the savings potential from energy-intensive refining processes...
Automatic Scheme Selection for Toolkit Hex Meshing
TAUTGES,TIMOTHY J.; WHITE,DAVID R.
1999-09-27T23:59:59.000Z
Current hexahedral mesh generation techniques rely on a set of meshing tools, which when combined with geometry decomposition leads to an adequate mesh generation process. Of these tools, sweeping tends to be the workhorse algorithm, accounting for at least 50% of most meshing applications. Constraints which must be met for a volume to be sweepable are derived, and it is proven that these constraints are necessary but not sufficient conditions for sweepability. This paper also describes a new algorithm for detecting extruded or sweepable geometries. This algorithm, based on these constraints, uses topological and local geometric information, and is more robust than feature recognition-based algorithms. A method for computing sweep dependencies in volume assemblies is also given. The auto sweep detect and sweep grouping algorithms have been used to reduce interactive user time required to generate all-hexahedral meshes by filtering out non-sweepable volumes needing further decomposition and by allowing concurrent meshing of independent sweep groups. Parts of the auto sweep detect algorithm have also been used to identify independent sweep paths, for use in volume-based interval assignment.
Automatic scheme selection for toolkit hex meshing
WHITE,DAVID R.; TAUTGES,TIMOTHY J.
2000-02-17T23:59:59.000Z
Current hexahedral mesh generation techniques rely on a set of meshing tools, which when combined with geometry decomposition leads to an adequate mesh generation process. Of these tools, sweeping tends to be the workhorse algorithm, accounting for at least 50% of most meshing applications. Constraints which must be met for a volume to be sweepable are derived, and it is proven that these constraints are necessary but not sufficient conditions for sweepability. This paper also describes a new algorithm for detecting extruded or sweepable geometries. This algorithm, based on these constraints, uses topological and local geometric information, and is more robust than feature recognition-based algorithms. A method for computing sweep dependencies in volume assemblies is also given. The auto sweep detect and sweep grouping algorithms have been used to reduce interactive user time required to generate all-hexahedral meshes by filtering out non-sweepable volumes needing further decomposition and by allowing concurrent meshing of independent sweep groups. Parts of the auto sweep detect algorithm have also been used to identify independent sweep paths, for use in volume-based interval assignment.
U. S. refiners move into another challenging technical era
Hall, J.R. (Ashland Oil Inc., Ashland, KY (US))
1991-10-21T23:59:59.000Z
With the transition to unleaded gasoline scarcely behind us, another new era is dawning for the U.S. refiner. No one yet knows the exact configuration of the refinery of the future and no two refineries are likely to adapt in exactly the same way. What is certain, however, is that by the year 2000, refineries will be more technologically advanced, their products will be more environmentally acceptable, and their operators will be more highly trained. The typical U.S. refinery in the year 2000 will be located at an existing refinery site because economic and environmental considerations will make it impossible to build new grassroots capacity. As a result of the Clean Air act, the refinery of tomorrow will produce cleaner fuels The entire U.S. gasoline pool will likely be reformulated. Most of the diesel fuel pool will consist of ultralow-sulfur product. And jet fuel-which is experiencing rapid demand growth-will be an increasingly important product. Many existing refining process will remain in use, but they will be more efficient and more technologically advanced. Energy efficiency will be a primary concern, as refiners seek to combat ever-increasing crude oil costs and refinery operating expenses. The refinery of the future also will be much more environmentally acceptable. The article is a closer look at the refinery of the future.
Anisotropic output-based adaptation with tetrahedral cut cells for compressible flows
Park, Michael Andrew
2008-01-01T23:59:59.000Z
Anisotropic, adaptive meshing for flows around complex, three-dimensional bodies remains a barrier to increased automation in computational fluid dynamics. Two specific advances are introduced in this thesis. First, a ...
The generation of hexahedral meshes for assembly geometries: A survey
TAUTGES,TIMOTHY J.
2000-02-14T23:59:59.000Z
The finite element method is being used today to model component assemblies in a wide variety of application areas, including structural mechanics, fluid simulations, and others. Generating hexahedral meshes for these assemblies usually requires the use of geometry decomposition, with different meshing algorithms applied to different regions. While the primary motivation for this approach remains the lack of an automatic, reliable all-hexahedral meshing algorithm, requirements in mesh quality and mesh configuration for typical analyses are also factors. For these reasons, this approach is also sometimes required when producing other types of unstructured meshes. This paper will review progress to date in automating many parts of the hex meshing process, which has halved the time to produce all-hex meshes for large assemblies. Particular issues which have been exposed due to this progress will also be discussed, along with their applicability to the general unstructured meshing problem.
Election algorithms in asynchronous mesh networks
Veeramacheneni, Ramu
1992-01-01T23:59:59.000Z
complexity in electing a single leader for an asynchronous square mesh network. Also, the other idea is to ensure no deadlocks. Peterson designed an election algorithm for asynchronous square meshes that uses about 100n messages in the worst case. When run... Claim 2. 3. 1 Claim 2. 3. 1-Case 2 30 31 Claim 2. 3. 1-Case 2. 2 32 10 Claim 2. 4. 1 Claim 2, 4. 1-Case 2 34 12 Lemma 3 36 13 14 Claim 4. 1 Claim 4. 2 Claim 4. 3. 1 37 38 39 Claim 4. 3, 1-Case 2. 2 40 17 Claim 4. 4. 1-Case 2 41 18 Claim...
Generation of high quality 2D meshes for given bathymetry
Colmenero, Jorge, S.B. Massachusetts Institute of Technology
2014-01-01T23:59:59.000Z
This thesis develops and applies a procedure to generate high quality 2D meshes for any given ocean region with complex coastlines. The different criteria used in determining mesh element sizes for a given domain are ...
Robustness improvement of polyhedral mesh method for airbag deployment simulations.
Vuik, Kees
Robustness improvement of polyhedral mesh method for airbag deployment simulations. TU Delft Description Airbag flexible membrane. Modeled by equations of elasticity, solved numerically using FEM Flow and Problem Description Airbag triangulation intersects in arbitrary way the Cartesian Mesh. Cartesian cells
Firing of pulverized solvent refined coal
Lennon, Dennis R. (Allentown, PA); Snedden, Richard B. (McKeesport, PA); Foster, Edward P. (Macungie, PA); Bellas, George T. (Library, PA)
1990-05-15T23:59:59.000Z
A burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired successfully without any performance limitations and without the coking of the solvent refined coal on the burner components. The burner is provided with a tangential inlet of primary air and pulverized fuel, a vaned diffusion swirler for the mixture of primary air and fuel, a center water-cooled conical diffuser shielding the incoming fuel from the heat radiation from the flame and deflecting the primary air and fuel steam into the secondary air, and a watercooled annulus located between the primary air and secondary air flows.
North Dakota Refining Capacity Study
Dennis Hill; Kurt Swenson; Carl Tuura; Jim Simon; Robert Vermette; Gilberto Marcha; Steve Kelly; David Wells; Ed Palmer; Kuo Yu; Tram Nguyen; Juliam Migliavacca
2011-01-05T23:59:59.000Z
According to a 2008 report issued by the United States Geological Survey, North Dakota and Montana have an estimated 3.0 to 4.3 billion barrels of undiscovered, technically recoverable oil in an area known as the Bakken Formation. With the size and remoteness of the discovery, the question became 'can a business case be made for increasing refining capacity in North Dakota?' And, if so what is the impact to existing players in the region. To answer the question, a study committee comprised of leaders in the region's petroleum industry were brought together to define the scope of the study, hire a consulting firm and oversee the study. The study committee met frequently to provide input on the findings and modify the course of the study, as needed. The study concluded that the Petroleum Area Defense District II (PADD II) has an oversupply of gasoline. With that in mind, a niche market, naphtha, was identified. Naphtha is used as a diluent used for pipelining the bitumen (heavy crude) from Canada to crude markets. The study predicted there will continue to be an increase in the demand for naphtha through 2030. The study estimated the optimal configuration for the refinery at 34,000 barrels per day (BPD) producing 15,000 BPD of naphtha and a 52 percent refinery charge for jet and diesel yield. The financial modeling assumed the sponsor of a refinery would invest its own capital to pay for construction costs. With this assumption, the internal rate of return is 9.2 percent which is not sufficient to attract traditional investment given the risk factor of the project. With that in mind, those interested in pursuing this niche market will need to identify incentives to improve the rate of return.
Source: Energy Information Administration, Form EIA-782A, "Refiners...
U.S. Energy Information Administration (EIA) Indexed Site
Gallons per Day Motor Gasoline No. 2 Distillate Residual Fuel Oil 5. U.S. Refiner Wholesale Petroleum Product Volumes Figure Percentages of Refiner Wholesale Volumes 1995...
Source: Energy Information Administration, Form EIA-782A, "Refiners...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
Gallons per Day Motor Gasoline No. 2 Distillate Residual Fuel Oil 5. U.S. Refiner Wholesale Petroleum Product Volumes Figure Percentages of Refiner Wholesale Volumes 1997...
Source: Energy Information Administration, Form EIA-782A, "Refiners...
Gasoline and Diesel Fuel Update (EIA)
Gallons per Day Motor Gasoline No. 2 Distillate Residual Fuel Oil 5. U.S. Refiner Wholesale Petroleum Product Volumes Figure Percentages of Refiner Wholesale Volumes 1996...
Improving NMR Protein Structure Quality by Rosetta Refinement...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
NMR Protein Structure Quality by Rosetta Refinement: A Molecular Replacement Study. Improving NMR Protein Structure Quality by Rosetta Refinement: A Molecular Replacement Study....
Social Network Analysis Plugin (SNAP) for Mesh Networks
Kotz, David
networks, called Mesh-Mon, that can help a team of system administrators (sysadmins) manage a wireless. In a wireless mesh network context, a system administrator should pay attention to "bridging nodes" sinceSocial Network Analysis Plugin (SNAP) for Mesh Networks Soumendra Nanda BAE Systems Burlington, MA
LNG FEM: Graded Meshes on Domains of Polygonal Structures
Nistor, Victor
LNG FEM: Graded Meshes on Domains of Polygonal Structures Hengguang Li and Victor Nistor Abstract. We develop LNG FEM, a software package for graded mesh generation and for solving elliptic equations. LNG FEM gen- erates user-specified graded meshes on arbitrary 2D domains with straight edges
A Meshing Pipeline for Biomedical Computing Michael Callahan1
Utah, University of
, will incorporate a flexible suite of tools that will offer some gener- ality to mesh generation of biomedical, mesh generation, and numerical simulations. An impor- tant requirement of the numerical approximation of the resulting visualizations. Historically, the generation of these meshes has been a significant bottleneck
Introducing Reference Semantics via Refinement Graeme Smith
Smith, Graeme
Introducing Reference Semantics via Refinement Graeme Smith Software Verification Research Centre, University of Queensland, Australia smith@svrc.uq.edu.au Abstract. Two types of semantics have been given
Efficient Spacetime Meshing with Nonlocal Cone Constraints
Thite, Shripad
displacement u(x, t) about the mean. utt - 2 uxx = 0 (i) wavespeed can be a constant or a function & Design (CPSD) An NSF-funded project at UIUC CS Jonathan Booth, Shuo-Heng Chung, Prof. Jeff Erickson, Prof Palaniappan Shripad Thite (thite@uiuc.edu) IMR'04 -- Spacetime meshing p. #12;Project Scope Implementation
Hierarchy-Direction Selective Approach for Locally Adaptive Sparse Grids
Stoyanov, Miroslav K [ORNL
2013-09-01T23:59:59.000Z
We consider the problem of multidimensional adaptive hierarchical interpolation. We use sparse grids points and functions that are induced from a one dimensional hierarchical rule via tensor products. The classical locally adaptive sparse grid algorithm uses an isotropic refinement from the coarser to the denser levels of the hierarchy. However, the multidimensional hierarchy provides a more complex structure that allows for various anisotropic and hierarchy selective refinement techniques. We consider the more advanced refinement techniques and apply them to a number of simple test functions chosen to demonstrate the various advantages and disadvantages of each method. While there is no refinement scheme that is optimal for all functions, the fully adaptive family-direction-selective technique is usually more stable and requires fewer samples.
Diffusive mesh relaxation in ALE finite element numerical simulations
Dube, E.I.
1996-06-01T23:59:59.000Z
The theory for a diffusive mesh relaxation algorithm is developed for use in three-dimensional Arbitary Lagrange/Eulerian (ALE) finite element simulation techniques. This mesh relaxer is derived by a variational principle for an unstructured 3D grid using finite elements, and incorporates hourglass controls in the numerical implementation. The diffusive coefficients are based on the geometric properties of the existing mesh, and are chosen so as to allow for a smooth grid that retains the general shape of the original mesh. The diffusive mesh relaxation algorithm is then applied to an ALE code system, and results from several test cases are discussed.
Refining and classifying finite-time Lyapunov exponent ridges
Allshouse, Michael R
2015-01-01T23:59:59.000Z
While more rigorous and sophisticated methods for identifying Lagrangian based coherent structures exist, the finite-time Lyapunov exponent (FTLE) field remains a straightforward and popular method for gaining some insight into transport by complex, time-dependent two-dimensional flows. In light of its enduring appeal, and in support of good practice, we begin by investigating the effects of discretization and noise on two numerical approaches for calculating the FTLE field. A practical method to extract and refine FTLE ridges in two-dimensional flows, which builds on previous methods, is then presented. Seeking to better ascertain the role of an FTLE ridge in flow transport, we adapt an existing classification scheme and provide a thorough treatment of the challenges of classifying the types of deformation represented by an FTLE ridge. As a practical demonstration, the methods are applied to an ocean surface velocity field data set generated by a numerical model.
Data-Parallel Mesh Connected Components Labeling and Analysis
Harrison, Cyrus; Childs, Hank; Gaither, Kelly
2011-04-10T23:59:59.000Z
We present a data-parallel algorithm for identifying and labeling the connected sub-meshes within a domain-decomposed 3D mesh. The identification task is challenging in a distributed-memory parallel setting because connectivity is transitive and the cells composing each sub-mesh may span many or all processors. Our algorithm employs a multi-stage application of the Union-find algorithm and a spatial partitioning scheme to efficiently merge information across processors and produce a global labeling of connected sub-meshes. Marking each vertex with its corresponding sub-mesh label allows us to isolate mesh features based on topology, enabling new analysis capabilities. We briefly discuss two specific applications of the algorithm and present results from a weak scaling study. We demonstrate the algorithm at concurrency levels up to 2197 cores and analyze meshes containing up to 68 billion cells.
Anderson, Charles H.
Green Petroleum Refining - Mathematical Models for Optimizing Petroleum Refining Under Emission understand that my thesis may be made electronically available to the public. #12;iii Abstract Petroleum and treating options for petroleum refinery waste streams. The performance of the developed model
An independent refiners approach to RFG
Czeskleba, M.
1994-12-31T23:59:59.000Z
This report was presented by Mike Czeskleba,Senior Business Analyst for Ashland Petroleum Company in Ashland, Kentucky. Ashland is one of the largest independent refiners and a leading marketer of gasoline and other petroleum products in the U.S. The issues addressed in this report concern the use of ethanol as a gasoline extender and renewable oxygenate, and its use in Reformulated Gasolines (RFG). The impact of Clean Air Act requirements for 1995 and beyond on petroleum refiners and producers is discussed. Some of the strategies which Ashland Petroleum Company is using to meet regulation requirements is also presented.
Topic Models to Interpret MeSH MEDLINE's Medical Subject Headings
Newman, David
://ii.nlm.nih.gov/mti.shtml #12;MeSH heading Major MeSH heading Major qualifier MeSH-qualifier combination Humans Brain metabolism Brain (metabolism) Table 1. Most frequent MeSH headings, major MeSH headings, major qualifiers and MeTopic Models to Interpret MeSH MEDLINE's Medical Subject Headings David Newman12 , Sarvnaz Karimi
Transforming and Refining Abstract Constraint Specifications
Walsh, Toby
Transforming and Refining Abstract Constraint Specifications Alan M. Frisch1 , Brahim Hnich2 , Ian choose model transformations to reduce greatly the amount of effort that is required to solve a problem by systematic search. It is a consid- erable challenge to automate such transformations. A problem may be viewed
Sudbury: Nickel Smelting and Refining Nickel Production
Toohey, Darin W.
Sudbury: Nickel Smelting and Refining Nickel Production o Toyota buys most of its nickel from Sudbury to produce its nickel- metal hydride batteries Used in cars such as the Toyota Prius SO2 Emissions o The smelting of nickel = large amount of SO2 released as byproduct 4 metric tons of SO2 per
Focus on Venezuelan heavy crude: refining margins
Not Available
1984-01-25T23:59:59.000Z
Of six crudes refined in the US Gulf Coast, heavy Venezuelan crude Lagunillas (15/sup 0/ API) provides the best margin per barrel. Data for end of December 1983 and the first three weeks of January show that margins on all crudes are on the rise in this market, due to a turnaround in product prices. The lighter crudes are showing the greatest increase in Gross Product Worth. This is having a modest shrinking effect on the margin differential between light and heavy crudes in this market. The domestic crude West Texas Intermediate, at 40/sup 0/ API, provides the highest GPW in this crude slate sample, over US $31 per barrel, compared to GPW of under US $28 per barrel for Lagunillas. Still, as Lagunillas cost about US $8 less than does WTI, refiners with sufficient residue conversion capacity can be earning about US $3.50 more in margin per barrel than they can with WTI. Although few refiners would be using a 15/sup 0/ API crude exclusively for any length of time, heavier oil's inclusion in modern refiners' diets is enhancing their competitive position more than any other single factor. This issue of Energy Detente presents the fuel price/tax series and industrial fuel prices for January 1984 for countries of the Western Hemisphere.
Rotordynamic evaluation of hybrid damper seals with metal mesh elements
Bhamidipati, Laxmi Narasimha Kameswara Sarma
2003-01-01T23:59:59.000Z
. . CHAPTFR 1 INTRODUCTION Literature Review II RESEARCH OBJECTIVES AND METHOD. Obj ective Method . III LEAKAGE TESTS . . . . I 0 Experimental Apparatus and Instrumentation. . . Procedure Results IV ROTATING TESTS . . . . I 0 . . . . 10 . . . . I... metal mesh elements. Figure 1: The New MHS Figure 2: New Metal Mesh Elements Figure 3: Comparison between Old and New Metal Mesh Elements 10 CHAPTER III LEAKAGE TESTS Since the primary objective of a seal is to prevent leakage from the high...
Optimization Online - Efficient and Fair Routing for Mesh Networks
Andrea Lodi
2010-02-08T23:59:59.000Z
Feb 8, 2010 ... Abstract: Inspired by the One Laptop Per Child project, we consider mesh networks that connect devices that cannot recharge their batteries ...
Multi-hop routing for wireless mesh networks
Bhorkar, Abhijeet
2012-01-01T23:59:59.000Z
in Wireless Mesh Networks . . . . . . . . . . . . . 1.2in Mobile, Ad Hoc, and Wireless Networks (WiOpt), [45] Amanin ICDCS Workshop on Wireless Networks and Mobile Computing,
Refining industry trends: Europe and surroundings
Guariguata, U.G.
1997-05-01T23:59:59.000Z
The European refining industry, along with its counterparts, is struggling with low profitability due to excess primary and conversion capacity, high operating costs and impending decisions of stringent environmental regulations that will require significant investments with hard to justify returns. This region was also faced in the early 1980s with excess capacity on the order of 4 MMb/d and satisfying the {open_quotes}at that point{close_quotes} demand by operating at very low utilization rates (60%). As was the case in the US, the rebalancing of the capacity led to the closure of some 51 refineries. Since the early 1990s, the increase in demand growth has essentially balanced the capacity threshold and utilization rates are settled around the 90% range. During the last two decades, the major oil companies have reduced their presence in the European refining sector, giving some state oil companies and producing countries the opportunity to gain access to the consumer market through the purchase of refining capacity in various countries-specifically, Kuwait in Italy; Libya and Venezuela in Germany; and Norway in other areas of Scandinavia. Although the market share for this new cast of characters remains small (4%) relative to participation by the majors (35%), their involvement in the European refining business set the foundation whereby US independent refiners relinquished control over assets that could not be operated profitably as part of a previous vertically integrated structure, unless access to the crude was ensured. The passage of time still seems to render this model valid.
Fast Algorithms for Computing Self-Avoiding Walks and Mesh Intersections over Unstructured Meshes1
Chen, Sheng-Wei
Dynamics Conference, Orlando, FL, U.S.A., June 23{26, 2003. 1This work was partially supported by the NSC-Ignition gasoline engine 14], the blades in a gas turbine, and a deforming droplet in the vicinity of a nozzle requires O(N1N2) time complexity to test whether a triangle in the second unstructured mesh intersects
Grain Refinement of Permanent Mold Cast Copper Base Alloys
M.Sadayappan; J.P.Thomson; M.Elboujdaini; G.Ping Gu; M. Sahoo
2005-04-01T23:59:59.000Z
Grain refinement is a well established process for many cast and wrought alloys. The mechanical properties of various alloys could be enhanced by reducing the grain size. Refinement is also known to improve casting characteristics such as fluidity and hot tearing. Grain refinement of copper-base alloys is not widely used, especially in sand casting process. However, in permanent mold casting of copper alloys it is now common to use grain refinement to counteract the problem of severe hot tearing which also improves the pressure tightness of plumbing components. The mechanism of grain refinement in copper-base alloys is not well understood. The issues to be studied include the effect of minor alloy additions on the microstructure, their interaction with the grain refiner, effect of cooling rate, and loss of grain refinement (fading). In this investigation, efforts were made to explore and understand grain refinement of copper alloys, especially in permanent mold casting conditions.
5.841 Crystal Structure Refinement, Fall 2006
Mueller, Peter
This course in crystal structure refinement examines the practical aspects of crystal structure determination from data collection strategies to data reduction and basic and advanced refinement problems of organic and ...
5.067 Crystal Structure Refinement, Fall 2007
Mueller, Peter
This course in crystal structure refinement examines the practical aspects of crystal structure determination from data collection strategies to data reduction and basic and advanced refinement problems of organic and ...
Finding Regions of Interest on Toroidal Meshes
Wu, Kesheng; Sinha, Rishi R; Jones, Chad; Ethier, Stephane; Klasky, Scott; Ma, Kwan-Liu; Shoshani, Arie; Winslett, Marianne
2011-02-09T23:59:59.000Z
Fusion promises to provide clean and safe energy, and a considerable amount of research effort is underway to turn this aspiration intoreality. This work focuses on a building block for analyzing data produced from the simulation of microturbulence in magnetic confinementfusion devices: the task of efficiently extracting regions of interest. Like many other simulations where a large amount of data are produced,the careful study of ``interesting'' parts of the data is critical to gain understanding. In this paper, we present an efficient approach forfinding these regions of interest. Our approach takes full advantage of the underlying mesh structure in magnetic coordinates to produce acompact representation of the mesh points inside the regions and an efficient connected component labeling algorithm for constructingregions from points. This approach scales linearly with the surface area of the regions of interest instead of the volume as shown with bothcomputational complexity analysis and experimental measurements. Furthermore, this new approach is 100s of times faster than a recentlypublished method based on Cartesian coordinates.
Using supercritical fluids to refine hydrocarbons
Yarbro, Stephen Lee
2014-11-25T23:59:59.000Z
This is a method to reactively refine hydrocarbons, such as heavy oils with API gravities of less than 20.degree. and bitumen-like hydrocarbons with viscosities greater than 1000 cp at standard temperature and pressure using a selected fluid at supercritical conditions. The reaction portion of the method delivers lighter weight, more volatile hydrocarbons to an attached contacting device that operates in mixed subcritical or supercritical modes. This separates the reaction products into portions that are viable for use or sale without further conventional refining and hydro-processing techniques. This method produces valuable products with fewer processing steps, lower costs, increased worker safety due to less processing and handling, allow greater opportunity for new oil field development and subsequent positive economic impact, reduce related carbon dioxide, and wastes typical with conventional refineries.
Dinosaurs can fly -- High performance refining
Treat, J.E. [Booz-Allen and Hamilton, Inc., San Francisco, CA (United States)
1995-09-01T23:59:59.000Z
High performance refining requires that one develop a winning strategy based on a clear understanding of one`s position in one`s company`s value chain; one`s competitive position in the products markets one serves; and the most likely drivers and direction of future market forces. The author discussed all three points, then described measuring performance of the company. To become a true high performance refiner often involves redesigning the organization as well as the business processes. The author discusses such redesigning. The paper summarizes ten rules to follow to achieve high performance: listen to the market; optimize; organize around asset or area teams; trust the operators; stay flexible; source strategically; all maintenance is not equal; energy is not free; build project discipline; and measure and reward performance. The paper then discusses the constraints to the implementation of change.
Volume Decomposition and Feature Recognition for Hexahedral Mesh Generation
GADH,RAJIT; LU,YONG; TAUTGES,TIMOTHY J.
1999-09-27T23:59:59.000Z
Considerable progress has been made on automatic hexahedral mesh generation in recent years. Several automatic meshing algorithms have proven to be very reliable on certain classes of geometry. While it is always worth pursuing general algorithms viable on more general geometry, a combination of the well-established algorithms is ready to take on classes of complicated geometry. By partitioning the entire geometry into meshable pieces matched with appropriate meshing algorithm the original geometry becomes meshable and may achieve better mesh quality. Each meshable portion is recognized as a meshing feature. This paper, which is a part of the feature based meshing methodology, presents the work on shape recognition and volume decomposition to automatically decompose a CAD model into meshable volumes. There are four phases in this approach: (1) Feature Determination to extinct decomposition features, (2) Cutting Surfaces Generation to form the ''tailored'' cutting surfaces, (3) Body Decomposition to get the imprinted volumes; and (4) Meshing Algorithm Assignment to match volumes decomposed with appropriate meshing algorithms. The feature determination procedure is based on the CLoop feature recognition algorithm that is extended to be more general. Results are demonstrated over several parts with complicated topology and geometry.
Mesh Geometry Compression for Mobile Graphics Jongseok Lee
Lee, Seungyong
, for mobile graphics, API standards such as OpenGL ES and JSR-184 have been proposed [8], and the graphicsMesh Geometry Compression for Mobile Graphics Jongseok Lee POSTECH thirdeye@postech.ac.kr Sungyul--This paper presents a compression scheme for mesh geometry, which is suitable for mobile graphics. The main
An Improved Vertex Caching Scheme for 3D Mesh Rendering
Lin, Gang
An Improved Vertex Caching Scheme for 3D Mesh Rendering Gang Lin and Thomas P.-Y. Yu Abstract to the graphics pipeline during rendering. To make effective use of the cache and facilitate rendering, it is key effective algorithm for generating a sequence for efficient rendering of 3D polygonal meshes based on greedy
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
Validating Process Refinement with Ontologies , Gerd Groener2
Staab, Steffen
Validating Process Refinement with Ontologies Yuan Ren1 , Gerd Groener2 , Jens Lemcke3 , Tirdad University of Koblenz-Landau, 3 SAP AG Abstract. A crucial task in process management is the validation of process refinements. A process refinement is a process description in a more fine-grained representation
MECS 2006 - Petroleum Refining | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(FactDepartment ofLetterEconomy andTermsDepartment1|Petroleum Refining MECS 2006 -
Hex-dominant mesh generation using 3D constrained triangulation
OWEN,STEVEN J.
2000-05-30T23:59:59.000Z
A method for decomposing a volume with a prescribed quadrilateral surface mesh, into a hexahedral-dominated mesh is proposed. With this method, known as Hex-Morphing (H-Morph), an initial tetrahedral mesh is provided. Tetrahedral are transformed and combined starting from the boundary and working towards the interior of the volume. The quadrilateral faces of the hexahedra are treated as internal surfaces, which can be recovered using constrained triangulation techniques. Implementation details of the edge and face recovery process are included. Examples and performance of the H-Morph algorithm are also presented.
, and wavelets Kristofer Davis and Yaoguo Li, Center for Gravity, Electrical, and Magnetics, Colorado School transforms on a re-ordered parameter set. The adaptive mesh discretizes the model region by starting transforms by storing only significant coefficients of those functions. This not only increases the speed
Municipal wireless mesh networks as a competitive broadband delivery platform
Hassan-Ali, Mudhafar
2007-01-01T23:59:59.000Z
Recently there has been a growing interest in deploying Wireless Mesh Networks by municipalities. This interest stems from the desire to provide broadband connectivity to users lacking access to broadband alternatives. The ...
Analyte separation utilizing temperature programmed desorption of a preconcentrator mesh
Linker, Kevin L. (Albuquerque, NM); Bouchier, Frank A. (Albuquerque, NM); Theisen, Lisa (Albuquerque, NM); Arakaki, Lester H. (Edgewood, NM)
2007-11-27T23:59:59.000Z
A method and system for controllably releasing contaminants from a contaminated porous metallic mesh by thermally desorbing and releasing a selected subset of contaminants from a contaminated mesh by rapidly raising the mesh to a pre-determined temperature step or plateau that has been chosen beforehand to preferentially desorb a particular chemical specie of interest, but not others. By providing a sufficiently long delay or dwell period in-between heating pulses, and by selecting the optimum plateau temperatures, then different contaminant species can be controllably released in well-defined batches at different times to a chemical detector in gaseous communication with the mesh. For some detectors, such as an Ion Mobility Spectrometer (IMS), separating different species in time before they enter the IMS allows the detector to have an enhanced selectivity.
Properties of plain weave metallic wire mesh screens Zenghui Zhao
Peles, Yoav
, heat pipes, solar energy collector, thermal insu- lation, etc. Structures or laminates made of wire heat transfer by coating the heat transfer surface with a mesh screen is found in [2]. In recent years
Ordering schemes for parallel processing of certain mesh problems
O'Leary, D.
1984-09-01T23:59:59.000Z
In this work, some ordering schemes for mesh points are presented which enable algorithms such as the Gauss-Seidel or SOR iteration to be performed efficiently for the nine-point operator finite difference method on computers consisting of a two-dimensional grid of processors. Convergence results are presented for the discretization of u /SUB xx/ + u /SUB yy/ on a uniform mesh over a square, showing that the spectral radius of the iteration for these orderings is no worse than that for the standard row by row ordering of mesh points. Further applications of these mesh point orderings to network problems, more general finite difference operators, and picture processing problems are noted.
Effects of mesh density and flow conditioning in simulating 7-pin wire wrapped fuel pins.
Smith, J. G.; Babin, B. R.; Pointer, W. D.; Fischer, P. F. (Mathematics and Computer Science); ( NE); (Kansas State Univ.)
2008-01-01T23:59:59.000Z
In response to the goals outlined by the U.S. Department of Energy's Global Nuclear Energy Partnership program, Argonne National Laboratory has initiated an effort to create an integrated multi-physics multi-resolution thermal hydraulic simulation tool package for the evaluation of nuclear power plant design and safety. As part of this effort, the applicability of a variety of thermal hydraulic analysis methods for the prediction of heat transfer and fluid dynamics in the wire-wrapped fuel-rod bundles found in a fast reactor core is being evaluated. The work described herein provides an initial assessment of the capabilities of the general purpose commercial computational fluid dynamics code Star-CD for the prediction of fluid dynamic characteristics in a wire wrapped fast reactor fuel assembly. A 7-pin wire wrapped fuel rod assembly based on the dimensions of fuel elements in the concept Advanced Burner Test Reactor [1] was simulated for different mesh densities and domain configurations. A model considering a single axial span of the wire wrapped fuel assembly was initially used to assess mesh resolution effects. The influence of the inflow/outflow boundary conditions on the predicted flow fields in the single-span model were then investigated through comparisons with the central span region of models which included 3 and 5 spans. The change in grid refinement had minimal impact on the inter-channel exchange within the assembly resulting in roughly a 5 percent maximum difference. The central span of the 3-span and 5-span cases exhibits much higher velocities than the single span case,, with the largest deviation (15 to 20 percent) occurring furthest away from the wire spacer grids in the higher velocity regions. However, the differences between predicted flow fields in the 3-span and 5-span models are minimal.
Finite element meshing approached as a global minimization process
WITKOWSKI,WALTER R.; JUNG,JOSEPH; DOHRMANN,CLARK R.; LEUNG,VITUS J.
2000-03-01T23:59:59.000Z
The ability to generate a suitable finite element mesh in an automatic fashion is becoming the key to being able to automate the entire engineering analysis process. However, placing an all-hexahedron mesh in a general three-dimensional body continues to be an elusive goal. The approach investigated in this research is fundamentally different from any other that is known of by the authors. A physical analogy viewpoint is used to formulate the actual meshing problem which constructs a global mathematical description of the problem. The analogy used was that of minimizing the electrical potential of a system charged particles within a charged domain. The particles in the presented analogy represent duals to mesh elements (i.e., quads or hexes). Particle movement is governed by a mathematical functional which accounts for inter-particles repulsive, attractive and alignment forces. This functional is minimized to find the optimal location and orientation of each particle. After the particles are connected a mesh can be easily resolved. The mathematical description for this problem is as easy to formulate in three-dimensions as it is in two- or one-dimensions. The meshing algorithm was developed within CoMeT. It can solve the two-dimensional meshing problem for convex and concave geometries in a purely automated fashion. Investigation of the robustness of the technique has shown a success rate of approximately 99% for the two-dimensional geometries tested. Run times to mesh a 100 element complex geometry were typically in the 10 minute range. Efficiency of the technique is still an issue that needs to be addressed. Performance is an issue that is critical for most engineers generating meshes. It was not for this project. The primary focus of this work was to investigate and evaluate a meshing algorithm/philosophy with efficiency issues being secondary. The algorithm was also extended to mesh three-dimensional geometries. Unfortunately, only simple geometries were tested before this project ended. The primary complexity in the extension was in the connectivity problem formulation. Defining all of the interparticle interactions that occur in three-dimensions and expressing them in mathematical relationships is very difficult.
Electron beam skull melting and refining of secondary copper
Bychkov, Y.; Ladokhin, S. [Donetskvtortsvetmet, Donetsk (Ukraine)
1995-12-31T23:59:59.000Z
Electron Beam Melting is the most efficient technology for metals and alloys refining. For secondary metals processing the Electron Beam Skull Melting (EBSM) with the electromagnetic stirring (EMS) of melt in the crucible was shown to be the most appropriate. The copper produced by EBSM with EMS possesses higher density and electric conductivity in comparison with other refining methods. The details for high power electrical machines were cast of the copper waste refined by EBSM technology.
Durnbaugh, A.
2011-01-01T23:59:59.000Z
? Built Environment ? Natural Environment ? People FIVE STRATEGIES Copyright 2011, City of Chicago ADAPTATION ESL-KT-11-11-16 9 CCAP Adaptation Evolution 2007 2008 2009 2010 ? Understood the climate science: Assess climate impacts... E xi st in g Tr un k Existing on Rogers Rogers Ave CIP Stormwater management: Chicago?s comprehensive sewer model Climate impacts Example actions to prepare the built environment Copyright 2011, City of Chicago ESL-KT-11-11-16 13 CCAP...
Feature based volume decomposition for automatic hexahedral mesh generation
LU,YONG; GADH,RAJIT; TAUTGES,TIMOTHY J.
2000-02-21T23:59:59.000Z
Much progress has been made through these years to achieve automatic hexahedral mesh generation. While general meshing algorithms that can take on general geometry are not there yet; many well-proven automatic meshing algorithms now work on certain classes of geometry. This paper presents a feature based volume decomposition approach for automatic Hexahedral Mesh generation. In this approach, feature recognition techniques are introduced to determine decomposition features from a CAD model. The features are then decomposed and mapped with appropriate automatic meshing algorithms suitable for the correspondent geometry. Thus a formerly unmeshable CAD model may become meshable. The procedure of feature decomposition is recursive: sub-models are further decomposed until either they are matched with appropriate meshing algorithms or no more decomposition features are detected. The feature recognition methods employed are convexity based and use topology and geometry information, which is generally available in BREP solid models. The operations of volume decomposition are also detailed in the paper. The final section, the capability of the feature decomposer is demonstrated over some complicated manufactured parts.
Table 44. Refiner Motor Gasoline Volumes by Formulation, Sales...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
250 Energy Information AdministrationPetroleum Marketing Annual 1999 Table 44. Refiner Motor Gasoline Volumes by Formulation, Sales Type, PAD District, and State (Thousand Gallons...
Table 44. Refiner Motor Gasoline Volumes by Formulation, Sales...
Gasoline and Diesel Fuel Update (EIA)
- - - - W W - - - - - - See footnotes at end of table. 44. Refiner Motor Gasoline Volumes by Formulation, Sales Type, PAD District, and State 292 Energy...
Table 43. Refiner Motor Gasoline Volumes by Grade, Sales Type...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
220 Energy Information AdministrationPetroleum Marketing Annual 1998 Table 43. Refiner Motor Gasoline Volumes by Grade, Sales Type, PAD District, and State (Thousand Gallons per...
Table 43. Refiner Motor Gasoline Volumes by Grade, Sales Type...
Gasoline and Diesel Fuel Update (EIA)
220 Energy Information AdministrationPetroleum Marketing Annual 1999 Table 43. Refiner Motor Gasoline Volumes by Grade, Sales Type, PAD District, and State (Thousand Gallons per...
Table 35. Refiner Motor Gasoline Prices by Grade, Sales Type...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
Energy Information Administration Petroleum Marketing Annual 1995 Table 35. Refiner Motor Gasoline Prices by Grade, Sales Type, PAD District, and State (Cents per Gallon...
Table 35. Refiner Motor Gasoline Prices by Grade, Sales Type...
Gasoline and Diesel Fuel Update (EIA)
134 Energy Information AdministrationPetroleum Marketing Annual 1998 Table 35. Refiner Motor Gasoline Prices by Grade, Sales Type, PAD District, and State (Cents per Gallon...
Petroleum Products Table 43. Refiner Motor Gasoline Volumes...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
220 Energy Information AdministrationPetroleum Marketing Annual 2000 Table 43. Refiner Motor Gasoline Volumes by Grade, Sales Type, PAD District, and State (Thousand Gallons per...
Table 43. Refiner Motor Gasoline Volumes by Grade, Sales Type...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
Energy Information Administration Petroleum Marketing Annual 1995 Table 43. Refiner Motor Gasoline Volumes by Grade, Sales Type, PAD District, and State (Thousand Gallons per...
Petroleum Products Table 43. Refiner Motor Gasoline Volumes...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
Energy Information Administration Petroleum Marketing Annual 1995 Table 43. Refiner Motor Gasoline Volumes by Grade, Sales Type, PAD District, and State (Thousand Gallons per...
Table 44. Refiner Motor Gasoline Volumes by Formulation, Sales...
U.S. Energy Information Administration (EIA) Indexed Site
250 Energy Information AdministrationPetroleum Marketing Annual 1998 Table 44. Refiner Motor Gasoline Volumes by Formulation, Sales Type, PAD District, and State (Thousand Gallons...
Table 44. Refiner Motor Gasoline Volumes by Formulation, Sales...
Gasoline and Diesel Fuel Update (EIA)
Energy Information Administration Petroleum Marketing Annual 1995 Table 44. Refiner Motor Gasoline Volumes by Formulation, Sales Type, PAD District, and State (Thousand Gallons...
Table 35. Refiner Motor Gasoline Prices by Grade, Sales Type...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
134 Energy Information AdministrationPetroleum Marketing Annual 1999 Table 35. Refiner Motor Gasoline Prices by Grade, Sales Type, PAD District, and State (Cents per Gallon...
ITP Petroleum Refining: Energy Efficiency Roadmap for Petroleum...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Energy Efficiency Roadmap for Petroleum Refineries in California ITP Petroleum Refining: Energy Efficiency Roadmap for Petroleum Refineries in California refiningroadmap.pdf More...
Table 19. U.S. Refiner Residual Fuel Oil Prices
U.S. Energy Information Administration (EIA) Indexed Site
Prices," source for backcast estimates prior to January 1983. 19. U.S. Refiner Residual Fuel Oil Prices 36 Energy Information Administration Petroleum Marketing Annual 1997...
Table 19. U.S. Refiner Residual Fuel Oil Prices
U.S. Energy Information Administration (EIA) Indexed Site
Prices," source for backcast estimates prior to January 1983. 19. U.S. Refiner Residual Fuel Oil Prices 36 Energy Information Administration Petroleum Marketing Annual 1996...
Source: Energy Information Administration, Form EIA-782A, "Refiners...
U.S. Energy Information Administration (EIA) Indexed Site
Refiner Retail Volumes 1996 Annual Averages Motor Gasoline No. 2 Distillate Propane Kero-jet Residual Fuel Oil Other Energy Information Administration Petroleum Marketing Annual...
Source: Energy Information Administration, Form EIA-782A, "Refiners...
U.S. Energy Information Administration (EIA) Indexed Site
Refiner Retail Volumes 1997 Annual Averages Motor Gasoline No. 2 Distillate Propane Kero-jet Residual Fuel Oil Other Energy Information Administration Petroleum Marketing Annual...
MESH-based Active Monte Carlo Recognition (MESH-AMCR) Felix v. Hundelshausen and H.J. Wunsche
Block, Marco
of recognizing categories of objects, such as cars, bikes or faces (see (Fei-Fei, Fergus, & Perona 2004), (Serre specific, identical objects, such a identifying a specific face or a specific building. Our approach MESH
Utah, University of
, this pipeline will incorporate a flexible suite of tools that will offer some generality to mesh generation, geometric modeling (segmentation, mesh generation), material modeling, numerical approximation (finite many of the visualization results are displayed. Historically, the generation of these meshes has been
Parallel Triangular Decompositions of an Oil Refining Simulation Xiaodong Zhang
Moreno Maza, Marc
important process in oil refining is to separate the crude oil into various oil products. This process the composition of the various oil products in designed refining columns operated under a given set of conditions oil products. This process is called distilla- tion, which is a thermal separation method
Specification and Refinement of a RealTime Control System
Smith, Graeme
such approach via the specification and refinement of the wellÂknown Steam Boiler Control Problem. The case. These features, although not central to the Steam Boiler Control Problem, are typical of features which mustÂlevel (i.e., abstract) specification of the Steam Boiler Control Problem. This specification is refined
Feasibility of Organizations -A Refinement of Chemical Organization Theory
Hinze, Thomas
Feasibility of Organizations - A Refinement of Chemical Organization Theory with Application to P a theorem providing a criteria for an unfeasible organization. This is a refinement of organization theory organization. Key words: reaction networks, constructive dynamical systems, chem- ical organization theory
Adaptive Visuo-Haptic Rendering for Hybrid Modeling of Macromolecular Assemblies
Wriggers, Willy
Adaptive Visuo-Haptic Rendering for Hybrid Modeling of Macromolecular Assemblies Stefan Birmanns1-time load balancing of virtual reality and haptic render- ing. In structural biology a variety of image rendering. During critical load conditions the error metric of a dynamic mesh simplification technique
Changing System Interfaces Consistently: a New Refinement Strategy for CSP B
Doran, Simon J.
Changing System Interfaces Consistently: a New Refinement Strategy for CSP B Steve Schneider refinement in the context of CSP B. Our motivation to include this notion of refinement within the CSP B to change the events of a CSP process and the B machines when refining a system. Notions of refinement based
Electron beam cold hearth refining in Vallejo
Lowe, J.H.C. [Axel Johnson Metals, Inc., Vallejo, CA (United States)
1994-12-31T23:59:59.000Z
Electron Beam Cold Hearth Refining Furnace (EBCHR) in Vallejo, California is alive, well, and girding itself for developing new markets. A brief review of the twelve years experience with EBCHR in Vallejo. Acquisition of the Vallejo facility by Axel Johnson Metals, Inc. paves the way for the development of new products and markets. A discussion of some of the new opportunities for the advancement of EBCHR technology. Discussed are advantages to the EBCHR process which include: extended surface area of molten metal exposed to higher vacuum; liberation of insoluble oxide particles to the surface of the melt; higher temperatures that allowed coarse solid particles like carbides and carbonitrides to be suspended in the fluid metal as fine micro-segregates, and enhanced removal of volatile trace impurities like lead, bismuth and cadmium. Future work for the company includes the continued recycling of alloys and also fabricating stainless steel for the piping of chip assembly plants. This is to prevent `killer defects` that ruin a memory chip.
Adaptive Ray Tracing for Radiative Transfer around Point Sources
Tom Abel; Benjamin D. Wandelt
2001-11-01T23:59:59.000Z
We describe a novel adaptive ray tracing scheme to solve the equation of radiative transfer around point sources in hydrodynamical simulations. The angular resolution adapts to the local hydrodynamical resolution and hence is of use for adaptive meshes as well as adaptive smooth particle hydrodynamical simulations. Recursive creation of rays ensures ease of implementation. The multiple radial integrations needed to solve the time dependent radiative transfer are sped up significantly using a quad-tree once the rays are cast. Simplifications advantageous for methods with one radiation source are briefly discussed. The suggested method is easily generalized to speed up Monte Carlo radiative transfer techniques. In summary a nearly optimal use of long characteristics is presented and aspects of its implementation and comparison to other methods are given.
Mesh component design and software integration within SUMAA3d.
Freitag, L.
1999-01-13T23:59:59.000Z
The requirements of distributed-memory applications that use mesh management software tools are diverse, and building software that meets these requirements represents a considerable challenge. In this paper we discuss design requirements for a general, component approach for mesh management for use within the context of solving PDE applications on parallel computers. We describe recent efforts with the SUMAA3d package motivated by a component-based approach and show how these efforts have considerably improved both the flexibility and the usability of this software.
Reactor physics verification of the MCNP6 unstructured mesh capability
Burke, T. P. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Kiedrowski, B. C.; Martz, R. L. [X-Computational Physics Division, Monte Carlo Codes Group, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Martin, W. R. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States)
2013-07-01T23:59:59.000Z
The Monte Carlo software package MCNP6 has the ability to transport particles on unstructured meshes generated from the Computed-Aided Engineering software Abaqus. Verification is performed using benchmarks with features relevant to reactor physics - Big Ten and the C5G7 computational benchmark. Various meshing strategies are tested and results are compared to reference solutions. Computational performance results are also given. The conclusions show MCNP6 is capable of producing accurate calculations for reactor physics geometries and the computational requirements for small lattice benchmarks are reasonable on modern computing platforms. (authors)
Turbine component cooling channel mesh with intersection chambers
Lee, Ching-Pang; Marra, John J
2014-05-06T23:59:59.000Z
A mesh (35) of cooling channels (35A, 35B) with an array of cooling channel intersections (42) in a wall (21, 22) of a turbine component. A mixing chamber (42A-C) at each intersection is wider (W1, W2)) than a width (W) of each of the cooling channels connected to the mixing chamber. The mixing chamber promotes swirl, and slows the coolant for more efficient and uniform cooling. A series of cooling meshes (M1, M2) may be separated by mixing manifolds (44), which may have film cooling holes (46) and/or coolant refresher holes (48).
The Video Mesh: A Data Structure for Image-based Video Editing
Durand, Fredo
2009-12-16T23:59:59.000Z
This paper introduces the video mesh, a data structure for representing video as 2.5D "paper cutouts." The video mesh allows interactive editing of moving objects and modeling of depth, which enables 3D effects and ...
The Video Mesh: A Data Structure for Image-based Three-dimensional Video Editing
Chen, Jiawen
This paper introduces the video mesh, a data structure for representing video as 2.5D “paper cutouts.” The video mesh allows interactive editing of moving objects and modeling of depth, which enables 3D effects and ...
Durnbaugh, A.
2011-01-01T23:59:59.000Z
/pest introduction. Buildings Fa?ade & structural damage. Higher peak electricity demand. Lake Michigan Decreased lake ice in winter & lower lake levels. Greater stress on water resources in times of need. Homes Increased cooling costs & energy... of Chicago ? 2011 ESL-KT-11-11-16 3 Chicago River Promote & incentivize green infrastructure to manage stormwater. Monitor threat of aquatic invasive species. RESILIENCY Adaptation will help reduce the impact of the changes that can be expected...
Hydrogen and Fuel Cells - Refining the Message Initiating a National Dialogue and Educational Agenda
Eggert, Anthony; Kurani, Kenneth S; Turrentine, Tom; Ogden, Joan M; Sperling, Dan; Winston, Emily
2005-01-01T23:59:59.000Z
April 1, 2005 Hydrogen and Fuel Cells – Refining the MessageHydrogen and Fuel Cells – Refining the Message Initiating athe communication problem. Hydrogen and fuel cells have now
E-Print Network 3.0 - amerya petroleum refining Sample Search...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
) Petroleum Refining Efficiency: 150 ppm S RFG with MTBE: GBS (d) Petroleum Refining... Eficiency: ... Source: Argonne National Laboratory - GREET Model Project Collection:...
Terwilliger, T. C.; Los Alamos National Laboratory, Mailstop M888, Los Alamos, NM 87545, USA; Lawrence Berkeley National Laboratory, One Cyclotron Road, Building 64R0121, Berkeley, CA 94720, USA; Department of Haematology, University of Cambridge, Cambridge CB2 0XY, England
2008-01-01T23:59:59.000Z
Iterative model-building, structure refinement, and densitytool for iterative model- building, structure refinement andusing RESOLVE or TEXTAL model- building, RESOLVE statistical
A CRYSTALLINE, RED GREEN STRATEGY FOR MESHING HIGHLY DEFORMABLE OBJECTS WITH
Fedkiw, Ron
compress the mesh to tightly fit the object boundary using either masses and springs, the finite element- cific to the application at hand. The requirements for fluid flow and heat transfer where the mesh algorithm that produces both high quality elements and a mesh that is well conditioned for subsequent large
A Flexible Mesh-Generation Strategy for Image Representation Based on Data-Dependent Triangulation
Adams, Michael D.
A Flexible Mesh-Generation Strategy for Image Representation Based on Data-Dependent Triangulation A Flexible Mesh-Generation Strategy for Image Representation Based on Data-Dependent Triangulation by Ping Li schemes for image represen- tation are studied. A flexible mesh-generation framework and a highly
Source: Energy Information Administration, Form EIA-782A, "Refiners...
U.S. Energy Information Administration (EIA) Indexed Site
S O N D 0 10 20 30 40 50 60 70 1995 Cents per Gallon Excluding Taxes Retail < or 1% Wholesale < or 1% Retail > 1% Wholesale > 1% 7. U.S. Refiner Residual Fuel Oil Prices and...
Table 43. Refiner Motor Gasoline Volumes by Grade, Sales Type...
Gasoline and Diesel Fuel Update (EIA)
150.0 2,026.7 W W 234.5 161.7 - 396.3 See footnotes at end of table. 43. Refiner Motor Gasoline Volumes by Grade, Sales Type, PAD District, and State 262 Energy Information...
Table 43. Refiner Motor Gasoline Volumes by Grade, Sales Type...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
253.2 2,222.4 W W 206.4 134.3 - 340.7 See footnotes at end of table. 43. Refiner Motor Gasoline Volumes by Grade, Sales Type, PAD District, and State 262 Energy Information...
Petroleum Products Table 43. Refiner Motor Gasoline Volumes...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
150.0 2,026.7 W W 234.5 161.7 - 396.3 See footnotes at end of table. 43. Refiner Motor Gasoline Volumes by Grade, Sales Type, PAD District, and State 262 Energy Information...
Petroleum Products Table 43. Refiner Motor Gasoline Volumes...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
253.2 2,222.4 W W 206.4 134.3 - 340.7 See footnotes at end of table. 43. Refiner Motor Gasoline Volumes by Grade, Sales Type, PAD District, and State 262 Energy Information...
Consensus Clustering Algorithms: Comparison and Refinement Andrey Goder
Filkov, Vladimir
-deterministic clustering algorithms, e.g. K-means, are sensitive to the choice of the initial seed clusters; running K-meansConsensus Clustering Algorithms: Comparison and Refinement Andrey Goder Vladimir Filkov Computer
Source: Energy Information Administration, Form EIA-782A, "Refiners...
U.S. Energy Information Administration (EIA) Indexed Site
Refiner Retail Volumes 1995 Annual Averages Motor Gasoline No. 2 Distillate Propane Kero-jet Residual Fuel Oil Other 39.1% 17.4% 2.2% 32.0% 8.1% 1.1% Energy Information...
Japan`s refiner/marketers headed for major shakeout
NONE
1996-08-26T23:59:59.000Z
Japan`s downstream oil industry is in a state of crisis and headed for a major shakeout. The major catalyst for this was a dramatic deregulation step during April 1996 that allowed refined petroleum product imports by non-refiners. The move, together with a sharp drop in refining margins, falling retail gasoline prices, and a service station sector on the brink of collapse, are all leading to massive changes in the way the country`s refiners and marketers do business. This paper reviews the collapse of corporate profits during this period of deregulation; the development of a new price system geared toward bringing the prices of gasoline, fuel oil, and kerosene into line with each other to offset the fall in gasoline prices; and industry restructuring including mergers, acquisitions, and marketing consolidation. The paper then makes predictions on the outcome of these changes on the Japanese oil industry.
Polygons in Buildings and their Refined Side Lengths
Kapovich, Michael; Leeb, Bernhard; Millson, John J.
2009-01-01T23:59:59.000Z
1999. [Bro] K. Brown, Buildings, Springer, 1989. [BuBI] D.AMS, 2001. [D] M. Davis, Buildings are CAT(0), in “Geometryat Springerlink.com POLYGONS IN BUILDINGS AND THEIR REFINED
Steps taken at Malelane refinery to improve refined sugar quality
M Moodley; Pm Schorn
1997-01-01T23:59:59.000Z
The refinery at Malelane has in the past produced refined sugar for the consumer market. A decision was taken by the management of Transvaal Sugar (TSB) to produce a quality of refined sugar that would also be acceptable to the industrial and the export markets. The processes that were evaluated and implemented at the Malelane refinery during the past three seasons to achieve this objective, are described.
The Virtual Mesh: A Geometric Abstraction for Efficiently Computing Radiosity
Petitjean, Sylvain
, an abstraction of the input geometry that allows complex shapes to be illuminated as if they were simple are mapped while preserving their energy properties. Radiosity values are then computed on these supports, by exactly integrating curved surfaces in the resolution process, the virtual mesh allows complex scenes
Using Hierarchical Simplicial Meshes to Render Atmospheric Effects
Atalay, F. BetĂĽl
Using Hierarchical Simplicial Meshes to Render Atmospheric Effects F. Betul Atalay David M. Mount natural phenomena. An important problem in this area is that of rendering scenes containing atmospheric and smoke. Generating photorealistic renderings through ray-tracing is computationally very demanding
Blue Crab, Callinectes sapidus, Trap Selectivity Studies: Mesh Size
Blue Crab, Callinectes sapidus, Trap Selectivity Studies: Mesh Size VINCENT GUILLORY and PAUL had replaced drop nets and trot lines as the dominant gear in the commercial blue crab, Callinectes, LA 70343. ABSTRACT-Catch rates and sizes of blue crabs, Callinectes sapidus, were com pared in traps
Robustness improvement of polyhedral mesh method for airbag deployment simulations.
Vuik, Kees
Robustness improvement of polyhedral mesh method for airbag deployment simulations. TU Delft to simulate the deployment of airbags. The solution is approximated using Euler's equations d dt qd + S (q the boundary of the object immersed in the flow, the airbag. The geometry of the airbag is preserved
Hierarchical occlusion culling for arbitrarily-meshed height fields
Edmondson, Paul Michael
2004-09-30T23:59:59.000Z
Many graphics applications today have need for high-speed 3-D visualization of height fields. Most of these applications deal with the display of digital terrain models characterized by a simple, but vast, non-overlapping mesh of triangles. A great...
ENABLING ENERGY DEMAND RESPONSE WITH VEHICULAR MESH NETWORKS
Chuah, Chen-Nee
ENABLING ENERGY DEMAND RESPONSE WITH VEHICULAR MESH NETWORKS Howard CheHao Chang1, Haining Du2 compared to their counterparts such as laptops in nomad computing or sensor networks. First, vehicles response (DR) [1] for automatic utility usage retrievals and price dispatching. DR is a project in- itiated
Experimental Anatomy of Packet Losses in Wireless Mesh Networks
California at Davis, University of
reliability. The factors that we studied include traffic load, number of hops and flows, transmission rates for the system configuration and thereby improve the reliability of wireless mesh networks. I. INTRODUCTION to low-cost, off-the-shelf equipment. Many important civilian applications, including, but not limited to
PubMed advanced exercise: MeSH Searching
Rzepa, Henry S.
achilles tendon and click Search. With MeSH searches, you enter only one search term at a time and you don can remove the need to enter multiple alternative terms to describe the same concept. For the following exercise, please search PubMed using: a) search terms that feature within the following
Medially Based Meshing with Finite Element Analysis of Prostate Deformation
Crouch, Jessica R.
Medially Based Meshing with Finite Element Analysis of Prostate Deformation Jessica R. Crouch1 have approached prostate imaging problems using meth- ods that incorporate finite element analysis. Assume the prostate is a linearly elastic body and compute its deformation using finite element analysis
Convergence Tests for the Hamiltonian Particle-Mesh
Al Hanbali, Ahmad
. The Hamiltonian particle-mesh method (HPM) 4. Test: Burgers' solution to the SWE 5. Test: Iacono solution to the SWE Bremen 2008 Page 2 of 18 #12;Introduction & Motivation Why looking at convergence aspects of HPM, not really documented: - Order of accuracy? - Restrictions in choice HPM parameters to assure convergence
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
Anisotropic Mesh Adaptation for the Finite Element Solution of Anisotropic Diffusion Problems
Li, Xianping
2011-12-31T23:59:59.000Z
, it is very difficult and also expensive to align the coordinate in computations, especially when the plasma is also heterogeneous. Moreover, spurious solution (e.g., negative temperature) may occur which may lead to imaginary sound speed and cause problems... formations. A porous medium is a material permeated by an interconnected network of pores which are typically filled with a fluid (liquid or gas). Fig. 1.4 shows a sketch of a porous medium. One of the major tasks of petroleum engineering is to produce crude...
Improving the Performance of Uintah: A Large-Scale Adaptive Meshing Computational
Utah, University of
a software system in which fundamental chem- istry and engineering physics are fully coupled with nonlinear with a force much larger than expected leaving behind a 70 foot crater. Fortunately no one was hurt. Why did to convective and radiative heat fluxes from a fire which heats the container and the PBX. After some amount
Laser ray tracing in a parallel arbitrary Lagrangian-Eulerian adaptive mesh refi
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 - -/e),,sandLaserLaserSecurityLaser ray tracing
Prusa, Joseph
2012-05-08T23:59:59.000Z
This project had goals of advancing the performance capabilities of the numerical general circulation model EULAG and using it to produce a fully operational atmospheric global climate model (AGCM) that can employ either static or dynamic grid stretching for targeted phenomena. The resulting AGCM combined EULAGĂ˘Â?Â?s advanced dynamics core with the Ă˘Â?Â?physicsĂ˘Â?Âť of the NCAR Community Atmospheric Model (CAM). Effort discussed below shows how we improved model performance and tested both EULAG and the coupled CAM-EULAG in several ways to demonstrate the grid stretching and ability to simulate very well a wide range of scales, that is, multi-scale capability. We leveraged our effort through interaction with an international EULAG community that has collectively developed new features and applications of EULAG, which we exploited for our own work summarized here. Overall, the work contributed to over 40 peer- reviewed publications and over 70 conference/workshop/seminar presentations, many of them invited.
Zachmann, Gabriel
. Consistent Normal Orientation for Polygonal Meshes Pavel Borodin Gabriel Zachmann Reinhard Klein Institute
Numerical homogenization of concrete microstructures without explicit meshes
Sanahuja, Julien, E-mail: julien.sanahuja@edf.fr; Toulemonde, Charles, E-mail: charles.toulemonde@edf.fr
2011-12-15T23:59:59.000Z
Life management of electric hydro or nuclear power plants requires to estimate long-term concrete properties on facilities, for obvious safety and serviceability reasons. Decades-old structures are foreseen to be operational for several more decades. As a large number of different concrete formulations are found in EDF facilities, empirical models based on many experiments cannot be an option for a large fleet of power plant buildings. To build predictive models, homogenization techniques offer an appealing alternative. To properly upscale creep, especially at long term, a rather precise description of the microstructure is required. However, the complexity of the morphology of concrete poses several challenges. In particular, concrete is formulated to maximize the packing density of the granular skeleton, leading to aggregates spanning several length scales with small inter particle spacings. Thus, explicit meshing of realistic concrete microstructures is either out of reach of current meshing algorithms or would produce a number of degrees of freedom far higher than the current generic FEM codes capabilities. This paper proposes a method to deal with complex matrix-inclusions microstructures such as the ones encountered at the mortar or concrete scales, without explicitly meshing them. The microstructure is superimposed to an independent mesh, which is a regular Cartesian grid. This inevitably yields so called 'gray elements', spanning across multiple phases. As the reliability of the estimate of the effective properties highly depends on the behavior affected to these gray elements, special attention is paid to them. As far as the question of the solvers is concerned, generic FEM codes are found to lack efficiency: they cannot reach high enough levels of discretization with classical free meshes, and they do not take advantage of the regular structure of the mesh. Thus, a specific finite differences/finite volumes solver has been developed. At first, generic off-the-shelf linear system solvers were used. To further improve the efficiency in terms of memory requirements, specific variants of the preconditioned conjugate gradient were implemented. This allowed to homogenize the conductivity of a concrete-like microstructure using more than 10{sup 9} degrees of freedom on a rather common hardware for 2010 (a PC embedding 48 GB of RAM). Taking benefit of the properties of the regular Cartesian grid we have also investigated a multi-level method to improve the CPU efficiency of the code.
Infrared transparent frequency selective surface based on metallic meshes
Yu, Miao [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China) [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China); University of Chinese Academy of Sciences, Beijing, 100049 (China); Xu, Nianxi; Liu, Hai; Gao, Jinsong, E-mail: gaojs@ciomp.ac.cn [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China)] [Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China)
2014-02-15T23:59:59.000Z
This paper presents an infrared transparent frequency selective surface (ITFSS) based on metallic meshes. In this ITFSS structure, periodic cross-slot units are integrated on square metallic meshes empowered by coating and UV-lithography. A matching condition is proposed to avoid the distortion of units. Experimental results show that this ITFSS possesses a good transmittance of 80% in the infrared band of 3–5 ?m, and also a stable band-pass behavior at the resonance frequency of 36.4 GHz with transmittance of ?0.56 dB. Theoretical simulations about the ITFSS diffractive characteristics and frequency responses are also investigated. The novel ITFSS will attract renewed interest and be exploited for applications in various fields.
Fracture and Fragmentation of Simplicial Finite Elements Meshes using Graphs
Mota, A; Knap, J; Ortiz, M
2006-10-18T23:59:59.000Z
An approach for the topological representation of simplicial finite element meshes as graphs is presented. It is shown that by using a graph, the topological changes induced by fracture reduce to a few, local kernel operations. The performance of the graph representation is demonstrated and analyzed, using as reference the 3D fracture algorithm by Pandolfi and Ortiz [22]. It is shown that the graph representation initializes in O(N{sub E}{sup 1.1}) time and fractures in O(N{sub I}{sup 1.0}) time, while the reference implementation requires O(N{sub E}{sup 2.1}) time to initialize and O(N{sub I}{sup 1.9}) time to fracture, where NE is the number of elements in the mesh and N{sub I} is the number of interfaces to fracture.
US refiners choose variety of routes to MTBE
Rhodes, A.K.
1992-09-07T23:59:59.000Z
This paper reports that refiners and merchant manufacturers in the U.S. are gearing up to produce the large volumes of methyl tertiary butyl ether (MTBE) needed to comply with oxygenated gasoline requirements. The 1990 U.S. Clean Air Act Amendments specify that, as of the first of this coming November, gasoline containing a minimum of 2.7 wt % oxygen must be sold in 39 CO-nonattainment cities. Refiners and others are scurrying to bring MTBE capacity on line in time to meet this requirement. Many U.S. refiners already have some operating MTBE capacity, but this will not be nearly enough to meet the looming increase in demand. As a result, additional capacity is being constructed worldwide.
Numerical solution of plasma fluid equations using locally refined grids
Colella, P., LLNL
1997-01-26T23:59:59.000Z
This paper describes a numerical method for the solution of plasma fluid equations on block-structured, locally refined grids. The plasma under consideration is typical of those used for the processing of semiconductors. The governing equations consist of a drift-diffusion model of the electrons and an isothermal model of the ions coupled by Poisson's equation. A discretization of the equations is given for a uniform spatial grid, and a time-split integration scheme is developed. The algorithm is then extended to accommodate locally refined grids. This extension involves the advancement of the discrete system on a hierarchy of levels, each of which represents a degree of refinement, together with synchronization steps to ensure consistency across levels. A brief discussion of a software implementation is followed by a presentation of numerical results.
The US petroleum refining industry in the 1980's
Not Available
1990-10-11T23:59:59.000Z
As part of the EIA program on petroleum, The US Petroleum Refining Industry in the 1980's, presents a historical analysis of the changes that took place in the US petroleum refining industry during the 1980's. It is intended to be of interest to analysts in the petroleum industry, state and federal government officials, Congress, and the general public. The report consists of six chapters and four appendices. Included is a detailed description of the major events and factors that affected the domestic refining industry during this period. Some of the changes that took place in the 1980's are the result of events that started in the 1970's. The impact of these events on US refinery configuration, operations, economics, and company ownership are examined. 23 figs., 11 tabs.
Mesh size and code option effects of strength calculations
Kaul, Ann M [Los Alamos National Laboratory
2010-12-10T23:59:59.000Z
Modern Lagrangian hydrodynamics codes include numerical methods which allow calculations to proceed past the point obtainable by a purely Lagrangian scheme. These options can be employed as the user deems necessary to 'complete' a calculation. While one could argue that any calculation is better than none, to truly understand the calculated results and their relationship to physical reality, the user needs to understand how their runtime choices affect the calculated results. One step toward this goal is to understand the effect of each runtime choice on particular pieces of the code physics. This paper will present simulation results for some experiments typically used for strength model validation. Topics to be covered include effect of mesh size, use of various ALE schemes for mesh detangling, and use of anti-hour-glassing schemes. Experiments to be modeled include the lower strain rate ({approx} 10{sup 4} s{sup -1}) gas gun driven Taylor impact experiments and the higher strain rate ({approx} 10{sup 5}-10{sup 6} s{sup -1}) HE products driven perturbed plate experiments. The necessary mesh resolution and the effect of the code runtime options are highly dependent on the amount of localization of strain and stress in each experiment. In turn, this localization is dependent on the geometry of the experimental setup and the drive conditions.
MESH2D GRID GENERATOR DESIGN AND USE
Flach, G.; Smith, F.
2012-01-20T23:59:59.000Z
Mesh2d is a Fortran90 program designed to generate two-dimensional structured grids of the form [x(i),y(i,j)] where [x,y] are grid coordinates identified by indices (i,j). The x(i) coordinates alone can be used to specify a one-dimensional grid. Because the x-coordinates vary only with the i index, a two-dimensional grid is composed in part of straight vertical lines. However, the nominally horizontal y(i,j{sub 0}) coordinates along index i are permitted to undulate or otherwise vary. Mesh2d also assigns an integer material type to each grid cell, mtyp(i,j), in a user-specified manner. The complete grid is specified through three separate input files defining the x(i), y(i,j), and mtyp(i,j) variations. The overall mesh is constructed from grid zones that are typically then subdivided into a collection of smaller grid cells. The grid zones usually correspond to distinct materials or larger-scale geometric shapes. The structured grid zones are identified through uppercase indices (I,J). Subdivision of zonal regions into grid cells can be done uniformly, or nonuniformly using either a polynomial or geometric skewing algorithm. Grid cells may be concentrated backward, forward, or toward both ends. Figure 1 illustrates the above concepts in the context of a simple four zone grid.
Multi-Block Enhancement for Lagrangian Dendritic Mesh setup in Altair5
Douglass, Rodney W [Los Alamos National Laboratory
2010-12-15T23:59:59.000Z
Initial mesh setup for an ASC mUlti-physics code at LANL is done using Altair5. Altair5 assumes that the final mesh is composed of logical structured mesh blocks linked together at mesh boundaries to form, ultimately, an unstructured mesh. Within these blocks, meshes may have dendrites, that is, local regions where two zones share common edges (in two-dimensions, or faces in three-dimensions) with a single zone. In many cases, contiguous subsets of the initial set of blocks may have the same material assigned to them, but without smoothing the mesh would form a computationally challenging initial mesh. Some of these blocks may also have zones with nodes on domain boundaries. This paper reports on the implementation of multiblock smoothing in Altair5, which allows for dendrites and for moving boundary nodes. Dendritic nodes are constrained to be located at the average of their neighbor nodes while boundary nodes are constrained to move along the boundary geometry. Two fundamentally different smoothing methods were implemented. First, a variational principle is presented that balances zonal size and distortion via a user selected weighting with constraints imposed using penalty methods for dendritic nodes and Lagrange multipliers for boundary nodes. Second, the Laplace-Beltrami smoother is presented. This is a general elliptic smoother which can easily be modified to give Laplacian and Winslow-Crowley mesh smoothing. Results are shown for several test meshes of interest.
Trends in heavy oil production and refining in California
Olsen, D.K.; Ramzel, E.B.; Pendergrass, R.A. II.
1992-07-01T23:59:59.000Z
This report is one of a series of publications assessing the feasibility of increasing domestic heavy oil production and is part of a study being conducted for the US Department of Energy. This report summarizes trends in oil production and refining in Canada. Heavy oil (10{degrees} to 20{degrees} API gravity) production in California has increased from 20% of the state's total oil production in the early 1940s to 70% in the late 1980s. In each of the three principal petroleum producing districts (Los Angeles Basin, Coastal Basin, and San Joaquin Valley) oil production has peaked then declined at different times throughout the past 30 years. Thermal production of heavy oil has contributed to making California the largest producer of oil by enhanced oil recovery processes in spite of low oil prices for heavy oil and stringent environmental regulation. Opening of Naval Petroleum Reserve No. 1, Elk Hills (CA) field in 1976, brought about a major new source of light oil at a time when light oil production had greatly declined. Although California is a major petroleum-consuming state, in 1989 the state used 13.3 billion gallons of gasoline or 11.5% of US demand but it contributed substantially to the Nation's energy production and refining capability. California is the recipient and refines most of Alaska's 1.7 million barrel per day oil production. With California production, Alaskan oil, and imports brought into California for refining, California has an excess of oil and refined products and is a net exporter to other states. The local surplus of oil inhibits exploitation of California heavy oil resources even though the heavy oil resources exist. Transportation, refining, and competition in the market limit full development of California heavy oil resources.
Trends in heavy oil production and refining in California
Olsen, D.K.; Ramzel, E.B.; Pendergrass, R.A. II
1992-07-01T23:59:59.000Z
This report is one of a series of publications assessing the feasibility of increasing domestic heavy oil production and is part of a study being conducted for the US Department of Energy. This report summarizes trends in oil production and refining in Canada. Heavy oil (10{degrees} to 20{degrees} API gravity) production in California has increased from 20% of the state`s total oil production in the early 1940s to 70% in the late 1980s. In each of the three principal petroleum producing districts (Los Angeles Basin, Coastal Basin, and San Joaquin Valley) oil production has peaked then declined at different times throughout the past 30 years. Thermal production of heavy oil has contributed to making California the largest producer of oil by enhanced oil recovery processes in spite of low oil prices for heavy oil and stringent environmental regulation. Opening of Naval Petroleum Reserve No. 1, Elk Hills (CA) field in 1976, brought about a major new source of light oil at a time when light oil production had greatly declined. Although California is a major petroleum-consuming state, in 1989 the state used 13.3 billion gallons of gasoline or 11.5% of US demand but it contributed substantially to the Nation`s energy production and refining capability. California is the recipient and refines most of Alaska`s 1.7 million barrel per day oil production. With California production, Alaskan oil, and imports brought into California for refining, California has an excess of oil and refined products and is a net exporter to other states. The local surplus of oil inhibits exploitation of California heavy oil resources even though the heavy oil resources exist. Transportation, refining, and competition in the market limit full development of California heavy oil resources.
Reducing noise in moving-grid codes with strongly-centroidal Lloyd mesh regularization
Mocz, Philip; Pakmor, Rudiger; Genel, Shy; Springel, Volker; Hernquist, Lars
2015-01-01T23:59:59.000Z
A method for improving the accuracy of hydrodynamical codes that use a moving Voronoi mesh is described. Our scheme is based on a new regularization scheme that constrains the mesh to be centroidal to high precision while still allowing the cells to move approximately with the local fluid velocity, thereby retaining the quasi-Lagrangian nature of the approach. Our regularization technique significantly reduces mesh noise that is attributed to changes in mesh topology and deviations from mesh regularity. We demonstrate the advantages of our method on various test problems, and note in particular improvements obtained in handling shear instabilities, mixing, and in angular momentum conservation. Calculations of adiabatic jets in which shear excites Kelvin Helmholtz instability show reduction of mesh noise and entropy generation. In contrast, simulations of the collapse and formation of an isolated disc galaxy are nearly unaffected, showing that numerical errors due to the choice of regularization do not impact ...
Time Critical Isosurface Refinement And Smoothing V. Pascucci
Texas at Austin, University of
the global geometry of the embedding (no self- intersections) of any approximated level of detail: (i) a progressive al- gorithm that builds a multi-resolution surface by successive refine- ments so of the U.S. Depart- ment of Energy by University of California Lawrence Livermore National Laboratory under
Source: Energy Information Administration, Form EIA-782A, "Refiners...
U.S. Energy Information Administration (EIA) Indexed Site
4. U.S. Refiner Wholesale Petroleum Product Prices Figure J F M A M J J A S O N D 0 20 40 60 80 100 120 1996 Cents per Gallon Excluding Taxes Kero-jet Propane No. 1 Distillate No....
Source: Energy Information Administration, Form EIA-782A, "Refiners...
Gasoline and Diesel Fuel Update (EIA)
4. U.S. Refiner Wholesale Petroleum Product Prices Figure J F M A M J J A S O N D 0 20 40 60 80 100 120 1995 Cents per Gallon Excluding Taxes Kero-jet Propane No. 1 Distillate No....
Source: Energy Information Administration, Form EIA-782A, "Refiners...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
4. U.S. Refiner Wholesale Petroleum Product Prices Figure J F M A M J J A S O N D 0 20 40 60 80 100 120 1997 Cents per Gallon Excluding Taxes Kero-jet Propane No. 1 Distillate No....
Table 35. Refiner Motor Gasoline Prices by Grade, Sales Type...
U.S. Energy Information Administration (EIA) Indexed Site
71.8 W 70.5 78.9 W 76.0 83.6 W 69.2 75.2 See footnotes at end of table. 35. Refiner Motor Gasoline Prices by Grade, Sales Type, PAD District and State 176 Energy Information...
Table 35. Refiner Motor Gasoline Prices by Grade, Sales Type...
Gasoline and Diesel Fuel Update (EIA)
W 68.4 70.8 W W 78.6 W 85.7 81.8 W 69.3 73.8 See footnotes at end of table. 35. Refiner Motor Gasoline Prices by Grade, Sales Type, PAD District and State 176 Energy Information...
Refinement of the One-Copy Serializable Correctness Criterion
Muńoz, Francesc
Refinement of the One-Copy Serializable Correctness Criterion M. I. Ruiz-Fuertes, F. D. Mu~noz-Esco. Mu~noz-Esco´i Instituto Tecnol´ogico de Inform´atica Universidad Polit´ecnica de Valencia Camino de
Electron beam melting and refining state of the art 1995
Bakish, R. [ed.
1995-12-31T23:59:59.000Z
This is the proceedings of the Electron Beam Melting and Refining - State of the Art 1995 Conference. It contains 23 of the 30 scheduled papers. Papers cover an array of electron beam melting applications, from industrial plating of metal strip, through government work on manufacturing and processing fissile alloys. Separate abstracts have been prepared for articles from this proceedings.
Refining Hygienic Macros for Modules and Separate Compilation Matthias Blume
Blume, Matthias
Refining Hygienic Macros for Modules and Separate Compilation Matthias Blume Department of Computer of the assumptions hygienic macro systems are based on. We will investigate how these assumptions have to be changed, and the consequences for the construction of hygienic macro expanders. Macro expansion algorithms rely on their ability
Note on refined topological vertex, Jack polynomials and instanton counting
Jianfeng Wu
2010-12-10T23:59:59.000Z
In this article, we calculated the refined topological vertex for the one parameter case using the Jack symmetric functions. Also, we obtain the partition function for elliptic N=2 models, the results coincide with those of Nekrasov instanton counting partition functions for the $N=2^{\\ast}$ theories.
#PRL --A Proof Refinement Calculus for Classical Reasoning
Kreitz, Christoph
#ÂµPRL -- A Proof Refinement Calculus for Classical Reasoning in Computational Type Theory Nuria, 14482 Potsdam, Germany {brede,kreitz}@cs.uniÂpotsdam.de Abstract. We present a hybrid proof calculus #ÂµPRL to conÂ structive proofs and show that the restriction of #ÂµPRL to ÂµÂsafe proof terms is sound
PRL A Proof Refinement Calculus for Classical Reasoning
Kreitz, Christoph
ÂµPRL Â A Proof Refinement Calculus for Classical Reasoning in Computational Type Theory Nuria Brede, Germany {brede,kreitz}@cs.uni-potsdam.de Abstract. We present a hybrid proof calculus ÂµPRL that combines and show that the restriction of ÂµPRL to Âµ-safe proof terms is sound and complete for intuitionistic
Refining 31 P nuclear magnetic resonance spectroscopy for marine
Paytan, Adina
Refining 31 P nuclear magnetic resonance spectroscopy for marine particulate samples: Storage 31 P nuclear magnetic resonance (NMR) spectroscopy has recently been used to characterize phosphorus.e., no storage, refrigeration, freezing, and oven-drying and grinding) prior to extraction for solution 31 P
Department of Computing Stepwise Refinement in Event-B||CSP
Doran, Simon J.
in Event-B||CSP Part 1: Safety Steve Schneider, Helen Treharne and Heike Wehrheim March 12th 2011 #12;Stepwise Refinement in Event-B CSP Part 1: Safety Steve Schneider1 Helen Treharne1 Heike Wehrheim2 1, 2011 Contents 1 Introduction 3 2 CSP 3 2.1 Notation
Cummings, Julian C. [California Institute of Technology
2013-05-15T23:59:59.000Z
This project was a collaboration between researchers at the California Institute of Technology and the University of California, Irvine to investigate the utility of a global field-aligned mesh and gyrokinetic field solver for simulations of the tokamak plasma edge region. Mesh generation software from UC Irvine was tested with specific tokamak edge magnetic geometry scenarios and the quality of the meshes and the solutions to the gyrokinetic Poisson equation were evaluated.
, Plastic Mesh Supporters, and Graphite Fiber Brush Anodes Xiaoyuan Zhang a , Shaoan Cheng b, c , Peng Liang (mW/m2 ) Reference Single brush Single Without plastic mesh or GF1 12 9.5±0.2 68±1 1160±21 This study Single brush Single Without plastic mesh, with GF1 12 11.8±2.1 74±4 1277±80 This study Single brush
The use of Fourier reverse transforms in crystallographic phase refinement
Ringrose, S.
1997-10-08T23:59:59.000Z
Often a crystallographer obtains an electron density map which shows only part of the structure. In such cases, the phasing of the trial model is poor enough that the electron density map may show peaks in some of the atomic positions, but other atomic positions are not visible. There may also be extraneous peaks present which are not due to atomic positions. A method for determination of crystal structures that have resisted solution through normal crystallographic methods has been developed. PHASER is a series of FORTRAN programs which aids in the structure solution of poorly phased electron density maps by refining the crystallographic phases. It facilitates the refinement of such poorly phased electron density maps for difficult structures which might otherwise not be solvable. The trial model, which serves as the starting point for the phase refinement, may be acquired by several routes such as direct methods or Patterson methods. Modifications are made to the reverse transform process based on several assumptions. First, the starting electron density map is modified based on the fact that physically the electron density map must be non-negative at all points. In practice a small positive cutoff is used. A reverse Fourier transform is computed based on the modified electron density map. Secondly, the authors assume that a better electron density map will result by using the observed magnitudes of the structure factors combined with the phases calculated in the reverse transform. After convergence has been reached, more atomic positions and less extraneous peaks are observed in the refined electron density map. The starting model need not be very large to achieve success with PHASER; successful phase refinement has been achieved with a starting model that consists of only 5% of the total scattering power of the full molecule. The second part of the thesis discusses three crystal structure determinations.
Radiation transport on unstructured mesh with parallel computers
Fan, W.C.; Drumm, C.R.
2000-07-01T23:59:59.000Z
This paper summarizes the developmental work on a deterministic transport code that provides multidimensional radiation transport capabilities on an unstructured mesh. The second-order form of the Boltzmann transport equation is solved utilizing the discrete ordinates angular differencing and the Galerkin finite element spatial differencing. The discretized system, which couples the spatial-angular dependence, is solved simultaneously using a parallel conjugate-gradient (CG) iterative solver. This approach eliminates the need for the conventional inner iterations over the discrete directions and is well-suited for massively parallel computers.
Mesh Generation for SHARP: Unprecedented Complexity | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(FactDepartment3311, 3312), OctoberMay 18-19,Department ofEnergyMesh Generation
Chau, Chi-Fai
1994-01-01T23:59:59.000Z
A technologically feasible cottonseed oil-isopropyl alcohol (IPA) miscella refining process was developed to produce high quality cottonseed oil. Individual steps necessary to refine cottonseed oil-IPA miscella were determined and improved...
WELDABILITY OF GRAIN-REFINED Fe-12Ni-0.25Ti STEEL FOR CRYOGENIC APPLICATIONS
Morris Jr., J.W.
2013-01-01T23:59:59.000Z
of the Cryogenic Nickel Steels, WRC Bull, 205, May, 1975.REFINED Fe-12Ni-0.25Ti STEEL FOR CRYOGENIC APPLICATIONS D.E.REFINED Fe-12Ni-0.25Ti STEEL FOR CRYOGENIC APPLICATIONS D.
Protein extraction in the refinement of Coastal Bermudagrass
De La Rosa Perez, Luis Bernardo
1992-01-01T23:59:59.000Z
, phosphoric acid, gaseous hydrochloric acid, anhydrous ammonia and ethylendiamine (Chang et aL, 1981; Wylie and Steen, 1988). Also the use of organic solvents such as hexane or cadoxen ([Cd(ethylendiamine)3](OH)2, cadmium ethylendiamine) (Ladisch et al... and lignin. Integrated conversion of the entire "barrel of biomass" (also referred to as biomass refining), is essential to obtain good system economics. This study evaluated the use of the Ammonia Fiber Explosion (AFEX) process in an integrated conversion...
EWO Mee'ng September 2012 Petrobras Refining Decision-Making Design
Grossmann, Ignacio E.
& Algorithm Thesis Prospectus Mathematical Modeling for Strategic and Investment Planning in the Oil-Refining Industry Brenno C. Menezes, Lincoln F. Moro Refining Op7miza7on PETROBRAS Petróleo SEWO Mee'ng September 2012 Petrobras Refining Decision-Making Design Thesis Formulation
Refinement and verification of concurrent systems specified in ObjectZ and CSP
Smith, Graeme
Refinement and verification of concurrent systems specified in ObjectZ and CSP Graeme SmithZ and CSP. A common semantic basis for the two languages enables a unified method of refinement to be used, based upon CSP refinement. To enable statebased techniques to be used for the ObjectZ components
H-Morph: An indirect approach to advancing front hex meshing
OWEN,STEVEN J.; SAIGAL,SUNIL
2000-05-30T23:59:59.000Z
H-Morph is a new automatic algorithm for the generation of a hexahedral-dominant finite element mesh for arbitrary volumes. The H-Morph method starts with an initial tetrahedral mesh and systematically transforms and combines tetrahedral into hexahedra. It uses an advancing front technique where the initial front consists of a set of prescribed quadrilateral surface facets. Fronts are individually processed by recovering each of the six quadrilateral faces of a hexahedron from the tetrahedral mesh. Recovery techniques similar to those used in boundary constrained Delaunay mesh generation are used. Tetrahedral internal to the six hexahedral faces are then removed and a hexahedron is formed. At any time during the H-Morph procedure a valid mixed hexahedral-tetrahedral mesh is in existence within the volume. The procedure continues until no tetrahedral remain within the volume, or tetrahedral remain which cannot be transformed or combined into valid hexahedral elements. Any remaining tetrahedral are typically towards the interior of the volume, generally a less critical region for analysis. Transition from tetrahedral to hexahedra in the final mesh is accomplished through pyramid shaped elements. Advantages of the proposed method include its ability to conform to an existing quadrilateral surface mesh, its ability to mesh without the need to decompose or recognize special classes of geometry, and its characteristic well-aligned layers of elements parallel to the boundary. Example test cases are presented on a variety of models.
SUPPLEMENTAL INFORMATION The Use and Optimization of Stainless Steel Mesh Cathodes in
of Hydrogen Energy (IJHE) #12;Mesh Surface Area Calculation Figure S1: SS 304 woven mesh configuration, where (or cm2 / cm2 ) Specific area per 7 cm2 cathode: 2 cm45.107 =Ă?S Specific area per reactor volume: 3232
Author's personal copy Power generation using an activated carbon and metal mesh cathode in a
Author's personal copy Power generation using an activated carbon and metal mesh cathode Engineering, Zhejiang University, Hangzhou 310027, PR China c Separation and Conversion Technology, VITO online 24 September 2009 Keywords: Microbial fuel cell Activated carbon Metal mesh Cathode a b s t r a c
Braun, Torsten
Solar-powered WirelessMesh Networksfor Environmental Monitoring Torsten Braun, Thomas Staub the development and experiencesof a solar-power driven wirelessmesh network for connectingsensorsin rural is available. II. SOLAR-POWER DRIVEN WIRELESS MESH NETWORK DEPLYOMENT AND OPERATION In a technology project
Burshid, Sami Muhammad
1999-01-01T23:59:59.000Z
, the metal mesh density and the amplitude of vibration of the seal journal on the metal mesh dynamic response. The second set was designed to check the effect of varying these three parameters in addition to the effect of varying the inlet pressure...
Case Study: A Visual Tool for Moving Mesh Numerical Methods Daryl H. Hepting \\Lambda
Zhang, Richard "Hao"
. Com puter visualization of moving mesh methods is an extension of an approach using computersCase Study: A Visual Tool for Moving Mesh Numerical Methods Daryl H. Hepting \\Lambda darylh differential equations are indispensable in scientific and engineering research, where they are used to model
Articulated Mesh Animation from Multi-view Silhouettes Daniel Vlasic Ilya Baran Wojciech Matusik
Popovic, Jovan
, and deformation model learning. CR Categories: I.3.7 [Computer Graphics]: Three Dimensional Graphics and Realism--AnimationArticulated Mesh Animation from Multi-view Silhouettes Daniel Vlasic Ilya Baran Wojciech Matusik Institute of Technology Abstract Details in mesh animations are difficult to generate but they have great
LNG FEM: GENERATING GRADED MESHES AND SOLVING ELLIPTIC EQUATIONS ON 2-D DOMAINS OF POLYGONAL, Minnesota 55455Â0436 Phone: 612-624-6066 Fax: 612-626-7370 URL: http://www.ima.umn.edu #12;LNG FEM AND VICTOR NISTOR Abstract. We develop LNG FEM, a software package for graded mesh gen- eration
Minimum Interference Channel Assignment in Multi-Radio Wireless Mesh Networks
Gupta, Himanshu
program and a linear program formulation of our optimization problem to obtain lower bounds on overall Mesh Networks, Channel Assignment, Graph Coloring, Interference, Mathe- matical Programming. I1 Minimum Interference Channel Assignment in Multi-Radio Wireless Mesh Networks Anand Prabhu
Suresh, Krishnan
Submitted to: Finite Elements in Analysis and Design 1 Finite Element Analysis over Tangled In modern finite element analysis (FEA), a mesh is said to be `tangled' if it contains one or more inverted are also illustrated. 1. INTRODUCTION In modern finite element analysis (FEA), the underlying mesh
On the Access Pricing and Network Scaling Issues of Wireless Mesh Networks
Lui, John C.S.
1 On the Access Pricing and Network Scaling Issues of Wireless Mesh Networks Ray K. Lam Dah. This paper studies the use of pricing as an incentive mechanism to stimulate participation and collaboration in public wireless mesh networks. Our focus is on the "economic behavior" of the network nodes-- the pricing
Topographic accuracy assessment of bare earth lidar-derived unstructured meshes Matthew V. Bilskie
Central Florida, University of
: Shallow water equations Unstructured mesh Lidar DEM Storm surge Accuracy a b s t r a c t This study water equations model. A methodology is developed to compute root mean square error (RMSE) and the 95th, urban regions, etc.) and have coarse mesh resolution in areas outside the focus region (e.g. deep water
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
Hamiltonian particle-mesh simulations for a non-hydrostatic vertical slice model
Reich, Sebastian
of the Hamiltonian Particle-Mesh (HPM) (Frank et al. 2002) and provides preservation of mass, momentum, and energy in Robert (1993). The accuracy of the solutions from the HPM simulation is comparable to those reported. More recently, the Hamiltonian particle-mesh (HPM) method has been introduced (Frank et al. 2002
Implicit Surface Tension Formulation with a Lagrangian Surface mesh on an Eulerian Simulation Grid
Thrun, Sebastian
Implicit Surface Tension Formulation with a Lagrangian Surface mesh on an Eulerian Simulation Grid framework for forces on a Lagrangian mesh to the case of surface tension force, which when treated explicitly leads to a tight t = O(x3/2 ) time step restriction. By applying surface tension as an implicit
Frey, Pascal
Semi-implicit surface tension formulation with a Lagrangian surface mesh on an Eulerian simulation mesh to the case of a surface tension force, which when treated explicitly leads to a tight time step restriction. By applying surface tension as a semi-implicit Lagrangian force, the resulting method benefits
How Many Potatoes Are in a Mesh? Marc van Kreveld1
Pach, János
How Many Potatoes Are in a Mesh? Marc van Kreveld1 , Maarten L¨offler1 , and J´anos Pach2 1 Dept analyze how many convex polygons (potatoes) can be con- structed by taking unions of triangles from Springer-Verlag Berlin Heidelberg 2012 #12;How Many Potatoes Are in a Mesh? 167 Table 1. Results
An optimization framework for monitoring multi-channel multi-radio wireless mesh networks q
Reisslein, Martin
, unless P = NP. We con- duct simulations in random networks and scale-free networks to evaluate November 2012 Keywords: Wireless mesh networks Multi-channel multi-radio wireless networks Security problem for behavior-based detection in multi- channel multi-radio wireless mesh networks. In behavior-based
Refined similarity hypotheses in shell models of turbulence
Emily S. C. Ching; H. Guo; T. S. Lo
2008-04-16T23:59:59.000Z
A major challenge in turbulence research is to understand from first principles the origin of anomalous scaling of the velocity fluctuations in high-Reynolds-number turbulent flows. One important idea was proposed by Kolmogorov [J. Fluid Mech. {\\bf 13}, 82 (1962)], which attributes the anomaly to the variations of the locally averaged energy dissipation rate. Kraichnan later pointed out [J. Fluid Mech. {\\bf 62}, 305 (1973)] that the locally averaged energy dissipation rate is not an inertial-range quantity and a proper inertial-range quantity would be the local energy transfer rate. As a result, Kraichnan's idea attributes the anomaly to the variations of the local energy transfer rate. These ideas, generally known as refined similarity hypotheses, can also be extended to study the anomalous scaling of fluctuations of an active scalar, like the temperature in turbulent convection. In this paper, we examine the validity of these refined similarity hypotheses and their extensions to an active scalar in shell models of turbulence. We find that Kraichnan's refined similarity hypothesis and its extension are valid.
Jarrell, Joshua
2012-02-14T23:59:59.000Z
?s DORT/ TORT Code . . . . . . . . . . . . 26 3.3 University of Florida?s PENTRAN Code . . . . . . . . . . . . . . . . 27 3.4 P.N. Brown?s Locally Refined Quadrature Rules . . . . . . . . . . . . 27 3.5 J.C. Stone?s 2D Adaptive Strategies... quadrature sets. We give overviews of the Oak Ridge National Laboratory?s DORT/TORT code, the University of Florida?s PENTRAN code , and Los Alamos National Laboratory?s Adaptive Strategies. We discuss J.C. Stone?s work in adaptive angular discretizations...
An efficient approach to unstructured mesh hydrodynamics on the cell broadband engine (u)
Ferenbaugh, Charles R [Los Alamos National Laboratory
2010-12-14T23:59:59.000Z
Unstructured mesh physics for the Cell Broadband Engine (CBE) has received little or no attention to date, largely because the CBE architecture poses particular challenges for unstructured mesh algorithms. SPU memory management strategies such as data preloading cannot be applied to the irregular memory storage patterns of unstructured meshes; and the SPU vector instruction set does not support the indirect addressing needed by connectivity arrays. This paper presents an approach to unstructured mesh physics that addresses these challenges, by creating a new mesh data structure and reorganizing code to give efficient CBE performance. The approach is demonstrated on the FLAG production hydrodynamics code using standard test problems, and results show an average speedup of more than 5x over the original code.
PubMed search tips March 2013, Medical Library Nijmegen MeSH Search Medical Subject Headings
van Suijlekom, Walter
or in selected fields, like title, abstract, author. Untagged terms that are entered in the search box with a MeSH term in PubMed you have 2 options: 1. Type the MeSH term in the PubMed search box adding [MeSH] 2. Find a term in the MeSH Database, click on Add to Search Builder (right of the screen
The Evolving Block Universe and the Meshing Together of Times
George F R Ellis
2014-07-27T23:59:59.000Z
It is proposed that spacetime should be regarded as an evolving block universe, bounded to the future by the present time, which continually extends to the future. This future boundary is defined at each time by measuring proper time along Ricci eigenlines from the start of the universe. A key point is that physical reality can be represented at many different scales: hence the passage of times may be seen as different at different scales, with quantum gravity determining the evolution of space time itself but quantum field theory determining the evolution of events within spacetime .The fundamental issue then arises as to how the effective times at different scales mesh together, leading to the concept so global and local times.
Three-dimensional gravity modeling and focusing inversion using rectangular meshes.
Commer, M.
2011-03-01T23:59:59.000Z
Rectangular grid cells are commonly used for the geophysical modeling of gravity anomalies, owing to their flexibility in constructing complex models. The straightforward handling of cubic cells in gravity inversion algorithms allows for a flexible imposition of model regularization constraints, which are generally essential in the inversion of static potential field data. The first part of this paper provides a review of commonly used expressions for calculating the gravity of a right polygonal prism, both for gravity and gradiometry, where the formulas of Plouff and Forsberg are adapted. The formulas can be cast into general forms practical for implementation. In the second part, a weighting scheme for resolution enhancement at depth is presented. Modelling the earth using highly digitized meshes, depth weighting schemes are typically applied to the model objective functional, subject to minimizing the data misfit. The scheme proposed here involves a non-linear conjugate gradient inversion scheme with a weighting function applied to the non-linear conjugate gradient scheme's gradient vector of the objective functional. The low depth resolution due to the quick decay of the gravity kernel functions is counteracted by suppressing the search directions in the parameter space that would lead to near-surface concentrations of gravity anomalies. Further, a density parameter transformation function enabling the imposition of lower and upper bounding constraints is employed. Using synthetic data from models of varying complexity and a field data set, it is demonstrated that, given an adequate depth weighting function, the gravity inversion in the transform space can recover geologically meaningful models requiring a minimum of prior information and user interaction.
Exact results on ABJ theory and the refined topological string
Masazumi Honda; Kazumi Okuyama
2014-07-22T23:59:59.000Z
We study the partition function of the ABJ theory, which is the N=6 superconformal Chern-Simons matter theory with gauge group U(N)xU(N+M) and Chern-Simons levels (k,-k). We exactly compute the ABJ partition function on a three sphere for various k, M and N via the Fermi gas approach. By using these exact data, we show that the ABJ partition function is completely determined by the refined topological string on local P^1 x P^1, including membrane instanton effects in the M-theory dual.
Minimally refined biomass fuel. [carbohydrate-water-alcohol mixture
Pearson, R.K.; Hirschfeld, T.B.
1981-03-26T23:59:59.000Z
A minimally refined fluid composition, suitable as a fuel mixture and derived from biomass material, is comprised of one or more water-soluble carbohydrates such as sucrose, one or more alcohols having less than four carbons, and water. The carbohydrate provides the fuel source; water-solubilizes the carbohydrate; and the alcohol aids in the combustion of the carbohydrate and reduces the viscosity of the carbohydrate/water solution. Because less energy is required to obtain the carbohydrate from the raw biomass than alcohol, an overall energy savings is realized compared to fuels employing alcohol as the primary fuel.
Changing Trends in the Refining Industry (released in AEO2006)
Reports and Publications (EIA)
2006-01-01T23:59:59.000Z
There have been some major changes in the U.S. refining industry recently, prompted in part by a significant decline in the quality of imported crude oil and by increasing restrictions on the quality of finished products. As a result, high-quality crudes, such as the West Texas Intermediate (WTI) crude that serves as a benchmark for oil futures on the New York Mercantile Exchange (NYMEX), have been trading at record premiums to the OPEC (Organization of the Petroleum Exporting Countries) Basket price.
REFINING PROGRAM HELPS REENERGIZE NEBRASKA UPGRADES | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreakingMay 2015 < prevQuick Guide: Power PurchaseOwner's Role3REFINING PROGRAM
Refining Bio-Oil alongside Petroleum | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreakingMay 2015 < prevQuick Guide:U.N.JuneAs part of itsRefining Bio-Oil
ITP Petroleum Refining: Petroleum Technology Vision 2020 | Department of
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't YourTransport(Fact Sheet),Energy Petroleum Technology Vision 2020 ITP Petroleum Refining:
Microfluidic sieve using intertwined, free-standing carbon nanotube mesh as active medium
Bakajin, Olgica (San Leandro, CA); Noy, Aleksandr (Belmont, CA)
2007-11-06T23:59:59.000Z
A microfluidic sieve having a substrate with a microfluidic channel, and a carbon nanotube mesh. The carbon nanotube mesh is formed from a plurality of intertwined free-standing carbon nanotubes which are fixedly attached within the channel for separating, concentrating, and/or filtering molecules flowed through the channel. In one embodiment, the microfluidic sieve is fabricated by providing a substrate having a microfluidic channel, and growing the intertwined free-standing carbon nanotubes from within the channel to produce the carbon nanotube mesh attached within the channel.
A new graphical user interface for a 3D topological mesh modeler
Morris, David Victor
2008-10-10T23:59:59.000Z
background color, or vice versa, while others may prefer an orange to blue contrast between the object color and the viewport background based on the sensitivity of their eyes [2]. There exist a myriad file formats for storing 3-dimensional mesh data..., and it is often desirable to work with the same mesh in multiple software packages. This requires each application to have the ability to import and export data in at least one of many 3D file formats. One of the most commonly used and widely support mesh formats...
is an open-source software suite for Partial Differential Equation
Alonso, Juan J.
-physics simulations · Adaptive, goal-oriented mesh refinement and sliding meshes Documentation and a full description.stanford.edu Analyze. Optimize. Design! DLR-F6 static pressure contours Sample Unstructured High-Fidelity Analysis and Optimization Baseline and Final N+2 surface pressure The New Open-Source CFD code
SURF 2005; final report Load Balancing Strategies for
SURF 2005; final report Load Balancing Strategies for Parallel SAMR Algorithms A Study of partial differential equations are important in many areas of science and technology. Only adaptive mesh in a load-balanced manner is even more difficult than for unstructured mesh refinement techniques. Therefore
Zachmann, Gabriel
. Consistent Normal Orientation for Polygonal Meshes Pavel Borodin Gabriel Zachmann Reinhard Klein Institute
California refiners move smoothly into next phase of RFG
Schaffer, S. [ed.
1996-05-01T23:59:59.000Z
The California RFG program (CARB RFG) began at the refinery level in March, the terminal level in April and will begin being enforced at the retail level June 1. By all accounts, early implementation is proceeding smoothly, with prices for both gasoline and oxygenates remaining fairly steady. Analysts labeled the introduction of the world`s cleanest gasoline {open_quotes}a non-event{close_quotes}. By April 1, more than half of the retail gasoline stations in California had fully complying CARB RFG. With cumulative investments of more than $3 billion, California`s refiners will be looking to recapture as much of the cost in the marketplace as possible. The incremental cost of CARB RFG production over federal RFG is estimated by refiners to be about 10{cents}/gal, mainly due to the capital investments needed for hydrotreating to reduce sulfur levels. Early batches of fuel on the spot market sold for about 8{cents}/gal over conventional prices, about 4.5{cents}/gal above federal RFG, according to the Oil Price Information Service (OPIS).
A refined model for characterizing x-ray multilayers
Oren, A.L.; Henke, B.L.
1987-12-01T23:59:59.000Z
The ability to quickly and accurately characterize arbitrary multilayers is very valuable for not only can we use the characterizations to predict the reflectivity of a multilayer for any soft x-ray wavelength, we also can generalize the results to apply to other multilayers of the same type. In addition, we can use the characterizations as a means of evaluating various sputtering environments and refining sputtering techniques to obtain better multilayers. In this report we have obtained improved characterizations for sample molybdenum-silicon and vanadium-silicon multilayers. However, we only examined five crystals overall, so the conclusions that we could draw about the structure of general multilayers is limited. Research involving many multilayers manufactured under the same sputtering conditions is clearly in order. In order to best understand multilayer structures it may be necessary to further refine our model, e.g., adopting a Gaussian form for the interface regions. With such improvements we can expect even better agreement with experimental values and continued concurrence with other characterization techniques. 18 refs., 30 figs., 7 tabs.
Parallel Volume-Rendering Algorithm Performance on Mesh-Connected Multicomputers
Shahabi, Cyrus
Parallel Volume-Rendering Algorithm Performance on Mesh-Connected Multicomputers Ulrich Neumann rendering algorithms. This issue has not been addressed in papers describing particular parallel implementations, but is pertinent to anyone dc- signing or implementing parallel rendering algorithms. Parallel
Experimental evaluation of wire mesh for design as a bearing damper
Choudhry, Vivek Vaibhav
2004-11-15T23:59:59.000Z
Wire mesh vibration dampers have been the subject of some very encouraging experiments at the Texas A&M Turbomachinery laboratories for the past several years and have emerged as an excellent replacement for squeeze film dampers. Their capability...
A Clean-Slate Architecture for Reliable Data Delivery in Wireless Mesh Networks
Lindemann, Christoph
A Clean-Slate Architecture for Reliable Data Delivery in Wireless Mesh Networks Sherif M. El, Germany Abstract-- In this paper, we introduce a clean-slate architecture for improving the delivery
Properties of Inconel 625 Mesh Structures Grown by Electron Beam Additive Manufacturing
List III, Frederick Alyious [ORNL; Dehoff, Ryan R [ORNL; Lowe, Larry E [ORNL; Sames, William J [ORNL
2014-01-01T23:59:59.000Z
Relationships between electron beam parameters (beam current, beam speed, and beam focus) and physical properties (mass, diameter, elastic modulus, and yield strength) have been investigated for Inconel 625 mesh cubes fabricated using an additive manufacturing technology based on electron beam melting. The elastic modulus and yield strength of the mesh cubes have been systematically varied by approximately a factor of ten by changing the electron beam parameters. Simple models have been used to understand better these relationships. Structural anisotropies of the mesh associated with the layered build architecture have been observed and may contribute, along with microstructural anisotropies, to the anisotropic mechanical properties of the mesh. Knowledge of this kind is likely applicable to other metal and alloy systems and is essential to rapidly realize the full potential of this burgeoning technology.
Experimental evaluation of a metal-mesh bearing damper in a high speed test rig
Zarzour, Mark Joseph
1999-01-01T23:59:59.000Z
Metal mesh is a commercially available material used in many applications including seals, heat shields, filters, gaskets, aircraft engine mounts, and vibration absorbers. This material has been tested in the Turbomachinery Laboratory at Texas A...
Experimental examination of wire mesh dampers subjected to large amplitude displacements
Jones, Adam Matthew
2009-06-02T23:59:59.000Z
, including: temperature insensitivity, oil-free operation, and the ability to contain large amplitude vibrations. Furthermore, due to their direct damping and lack of cross-coupled stiffness, the wire mesh reduces the response to imbalance and increases...
The use and optimization of stainless steel mesh cathodes in microbial electrolysis cells
achieve performance similar to carbon cathodes containing a platinum catalyst in MECs. SS mesh cathodes voltammetry at low bubble coverages (low current densities) was also consistent with performance on this basis
Conservation Properties of the Hamiltonian Particle-Mesh method for the
Frank, Jason
Computing, Computational Science #12;#12;Abstract The Hamiltonian particle-mesh (HPM) method is used . . . . . . . . . . . . . . 16 2.2 The QG model on a sphere . . . . . . . . . . . . . . . . . . . 17 3 The HPM Method 19 3
Performance evaluation of configurable arrays with mesh interconnections and wormhole routing
Krishnamoorthy, Deviusha
1997-01-01T23:59:59.000Z
applications (with and without the embeddings) are obtained through an execution driven simulation. The embeddings are shown to provide similar performance to the original mesh when the rectangular grid's height-width ratio is closer to unity. However...
Schempp, Philipp [BAM, Germany; Tang, Z. [BIAS, Germany; Cross, Carl E. [Los Alamos National Laboratory; Seefeld, T. [BIAS, Germany; Pittner, A. [BAM, Germany; Rethmeier, M. [BAM, Germany
2012-06-28T23:59:59.000Z
The goals are: (1) Establish how much Ti/B grain refiner is need to completely refine aluminum weld metal for different alloys and different welding conditions; (2) Characterize how alloy composition and solidification parameters affect weld metal grain refinement; and (3) Apply relevant theory to understand observed behavior. Conclusions are: (1) additions of Ti/B grain refiner to weld metal in Alloys 1050, 5083, and 6082 resulted in significant grain refinement; (2) grain refinement was more effective in GTAW than LBW, resulting in finer grains at lower Ti content - reason is limited time available for equiaxed grain growth in LBW (inability to occlude columnar grain growth); (3) welding travel speed did not markedly affect grain size within GTAW and LBW clusters; and (4) application of Hunt CET analysis showed experimental G to be on the order of the critical G{sub CET}; G{sub CET} was consistently higher for GTAW than for LBW.
A Pliant Method for Anisotropic Mesh Generation Frank J. Bossen
California at Berkeley, University of
elements conform well to the requested shape metric. The method appears particularly well suited to surface- ysis, heat transfer, fluid flow, electromagnetics, computer graphics, and other applications. It should interface that allows it to be used inside an adaptive finite element solver or in other contexts. allows
Impact of Environmental Compliance Costs on U.S. Refining Profitability 1995-2001
Reports and Publications (EIA)
2003-01-01T23:59:59.000Z
This report assesses the effects of pollution abatement requirements on the financial performance of U.S. petroleum refining and marketing operations during the 1995 to 2001 period. This study is a follow-up to the October 1997 publication entitled The Impact of Environmental Compliance Costs on U.S. Refining Profitability, that focused on the financial impacts of U.S. refining pollution abatement investment requirements in the 1988 to1995 period.
Connectivity-based, all-hexahedral mesh generation method and apparatus
Tautges, T.J.; Mitchell, S.A.; Blacker, T.D.; Murdoch, P.
1998-06-16T23:59:59.000Z
The present invention is a computer-based method and apparatus for constructing all-hexahedral finite element meshes for finite element analysis. The present invention begins with a three-dimensional geometry and an all-quadrilateral surface mesh, then constructs hexahedral element connectivity from the outer boundary inward, and then resolves invalid connectivity. The result of the present invention is a complete representation of hex mesh connectivity only; actual mesh node locations are determined later. The basic method of the present invention comprises the step of forming hexahedral elements by making crossings of entities referred to as ``whisker chords.`` This step, combined with a seaming operation in space, is shown to be sufficient for meshing simple block problems. Entities that appear when meshing more complex geometries, namely blind chords, merged sheets, and self-intersecting chords, are described. A method for detecting invalid connectivity in space, based on repeated edges, is also described, along with its application to various cases of invalid connectivity introduced and resolved by the method. 79 figs.
Connectivity-based, all-hexahedral mesh generation method and apparatus
Tautges, Timothy James (Albuquerque, NM); Mitchell, Scott A. (Albuquerque, NM); Blacker, Ted D. (Green Oaks, IL); Murdoch, Peter (Salt Lake City, UT)
1998-01-01T23:59:59.000Z
The present invention is a computer-based method and apparatus for constructing all-hexahedral finite element meshes for finite element analysis. The present invention begins with a three-dimensional geometry and an all-quadrilateral surface mesh, then constructs hexahedral element connectivity from the outer boundary inward, and then resolves invalid connectivity. The result of the present invention is a complete representation of hex mesh connectivity only; actual mesh node locations are determined later. The basic method of the present invention comprises the step of forming hexahedral elements by making crossings of entities referred to as "whisker chords." This step, combined with a seaming operation in space, is shown to be sufficient for meshing simple block problems. Entities that appear when meshing more complex geometries, namely blind chords, merged sheets, and self-intersecting chords, are described. A method for detecting invalid connectivity in space, based on repeated edges, is also described, along with its application to various cases of invalid connectivity introduced and resolved by the method.
AHF: Array-Based Half-Facet Data Structure for Mixed-Dimensional and Non-Manifold Meshes
Dyedov, Volodymyr; Ray, Navamita; Einstein, Daniel R.; Jiao, Xiangmin; Tautges, T.
2014-08-31T23:59:59.000Z
We present an Array-based Half-Facet mesh data structure, or AHF, for efficient mesh query and modification operations. The AHF extends the compact array-based half-edge and half-face data structures (T.J. Alumbaugh and X. Jiao, Compact array-based mesh data structures, IMR, 2005) to support mixed-dimensional and non-manifold meshes. The design goals of our data structure include generality to support such meshes, efficiency of neighborhood queries and mesh modification, compactness of memory footprint, and facilitation of interoperability of mesh-based application codes. To accomplish these goals, our data structure uses sibling half-facets as a core abstraction, coupled with other explicit and implicit representations of entities. A unique feature of our data structure is a comprehensive implementation in MATLAB, which allows rapid prototyping, debugging, testing, and deployment of meshing algorithms and other mesh-based numerical methods. We have also developed C++ implementation built on top of MOAB (T.J. Tautges, R. Meyers, and K. Merkley, MOAB: A Mesh-Oriented Database, Sandia National Laboratories, 2004). We present some comparisons of the memory requirements and computational costs, and also demonstrate its effectiveness with a few sample applications.
Table 7. U.S. Refiner Motor Gasoline Volumes by Grade and Sales...
U.S. Energy Information Administration (EIA) Indexed Site
Information Administration Petroleum Marketing Annual 1995 Table 7. U.S. Refiner Motor Gasoline Volumes by Grade and Sales Type (Million Gallons per Day) - Continued Year...
Table A1. Refiner/Reseller Motor Gasoline Prices by Grade, PAD...
U.S. Energy Information Administration (EIA) Indexed Site
AdministrationPetroleum Marketing Annual 1999 401 Table A1. RefinerReseller Motor Gasoline Prices by Grade, PAD District and State, 1984-Present (Cents per Gallon...
Table A1. Refiner/Reseller Motor Gasoline Prices by Grade, PAD...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
Information Administration Petroleum Marketing Annual 1995 Table A1. RefinerReseller Motor Gasoline Prices by Grade, PAD District and State, 1984-Present (Cents per Gallon...
Table 6. U.S. Refiner Motor Gasoline Prices by Grade and Sales...
U.S. Energy Information Administration (EIA) Indexed Site
Energy Information AdministrationPetroleum Marketing Annual 1999 Table 6. U.S. Refiner Motor Gasoline Prices by Grade and Sales Type (Cents per Gallon Excluding Taxes) - Continued...
Table 10. U.S. Refiner Oxygenated Motor Gasoline Prices by...
U.S. Energy Information Administration (EIA) Indexed Site
AdministrationPetroleum Marketing Annual 1999 Table 10. U.S. Refiner Oxygenated Motor Gasoline Prices by Grade and Sales Type (Cents per Gallon Excluding Taxes) Year Month...
Table 6. U.S. Refiner Motor Gasoline Prices by Grade and Sales...
U.S. Energy Information Administration (EIA) Indexed Site
Energy Information AdministrationPetroleum Marketing Annual 1998 Table 6. U.S. Refiner Motor Gasoline Prices by Grade and Sales Type (Cents per Gallon Excluding Taxes) - Continued...
Table 7. U.S. Refiner Motor Gasoline Volumes by Grade and Sales...
U.S. Energy Information Administration (EIA) Indexed Site
Energy Information AdministrationPetroleum Marketing Annual 1998 Table 7. U.S. Refiner Motor Gasoline Volumes by Grade and Sales Type (Million Gallons per Day) - Continued Year...
Table 6. U.S. Refiner Motor Gasoline Prices by Grade and Sales...
U.S. Energy Information Administration (EIA) Indexed Site
Information Administration Petroleum Marketing Annual 1995 Table 6. U.S. Refiner Motor Gasoline Prices by Grade and Sales Type (Cents per Gallon Excluding Taxes) - Continued...
Table 2. U.S. Refiner Prices of Petroleum Products to End Users
U.S. Energy Information Administration (EIA) Indexed Site
fuel. Note: Motor gasoline averages and totals prior to October 1993 include leaded gasoline. Sources: Energy Information Administration Form EIA-782A, "Refiners'Gas Plant...
RFA-14-0001 - In the Matter of Commonwealth Oil Refining Company...
Broader source: Energy.gov (indexed) [DOE]
both programs would reduce the dependence of Puerto Rican consumers on high cost imported oil and refined petroleum products and that, consequently, both programs were consistent...
Refining and Extending the Business Model with Information Technology: Dell Computer Corporation
Kraemer, Kenneth L; Dedrick, Jason; Yamashiro, Sandra
1999-01-01T23:59:59.000Z
of Dell’s Direct Business Model Fuels Fifteenth ConsecutiveAND EXTENDING THE REFINING AND EXTENDING THE BUSINESS MODELBUSINESS MODEL CENTER FOR RESEARCH ON INFORMATION TECHNOLOGY
OPERATOR INTERACTION WITH MODEL-BASED PREDICTIVE CONTROLLERS IN PETROCHEMICAL REFINING
Virginia, University of
OPERATOR INTERACTION WITH MODEL-BASED PREDICTIVE CONTROLLERS IN PETROCHEMICAL REFINING Greg A success in the petrochemical industry, they have introduced new challenges for the operators and engineers
Table A2. Refiner/Reseller Prices of Aviation Fuels, Propane...
Gasoline and Diesel Fuel Update (EIA)
Marketing Annual 1999 421 Table A2. RefinerReseller Prices of Aviation Fuels, Propane, and Kerosene, by PAD District, 1983-Present (Cents per Gallon Excluding Taxes) -...
Table A2. Refiner/Reseller Prices of Aviation Fuels, Propane...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
Marketing Annual 1995 467 Table A2. RefinerReseller Prices of Aviation Fuels, Propane, and Kerosene, by PAD District, 1983-Present (Cents per Gallon Excluding Taxes) -...
Quantitative Methods for Strategic and Investment Planning in the Oil-Refining
Grossmann, Ignacio E.
by one refinery Refinery Opera*onal Planning - Simulate the Refining Scenarios Supply Chain Investments Planning - Test the refinery best scenarios
Table 46. Refiner No. 2 Distillate, Diesel Fuel, and Fuel Oil...
Gasoline and Diesel Fuel Update (EIA)
Petroleum Marketing Annual 1998 295 Table 46. Refiner No. 2 Distillate, Diesel Fuel, and Fuel Oil Volumes by PAD District and State (Thousand Gallons per Day) - Continued...
Table 46. Refiner No. 2 Distillate, Diesel Fuel, and Fuel Oil...
Gasoline and Diesel Fuel Update (EIA)
Petroleum Marketing Annual 1995 337 Table 46. Refiner No. 2 Distillate, Diesel Fuel, and Fuel Oil Volumes by PAD District and State (Thousand Gallons per Day) - Continued...
Table 46. Refiner No. 2 Distillate, Diesel Fuel, and Fuel Oil...
U.S. Energy Information Administration (EIA) Indexed Site
Petroleum Marketing Annual 1999 295 Table 46. Refiner No. 2 Distillate, Diesel Fuel, and Fuel Oil Volumes by PAD District and State (Thousand Gallons per Day) - Continued...
Table A3. Refiner/Reseller Prices of Distillate and Residual...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
Marketing Annual 1999 441 Table A3. RefinerReseller Prices of Distillate and Residual Fuel Oils, by PAD District, 1983-Present (Cents per Gallon Excluding Taxes) - Continued...
Table 12. U.S. Refiner Reformulated Motor Gasoline Prices by...
U.S. Energy Information Administration (EIA) Indexed Site
Administration Petroleum Marketing Annual 1995 Table 12. U.S. Refiner Reformulated Motor Gasoline Prices by Grade and Sales Type (Cents per Gallon Excluding Taxes) - Continued...
Table 10. U.S. Refiner Oxygenated Motor Gasoline Prices by...
U.S. Energy Information Administration (EIA) Indexed Site
Administration Petroleum Marketing Annual 1995 Table 10. U.S. Refiner Oxygenated Motor Gasoline Prices by Grade and Sales Type (Cents per Gallon Excluding Taxes) - Continued...
Table 11. U.S. Refiner Oxygenated Motor Gasoline Volumes by...
U.S. Energy Information Administration (EIA) Indexed Site
Administration Petroleum Marketing Annual 1995 Table 11. U.S. Refiner Oxygenated Motor Gasoline Volumes by Grade and Sales Type (Million Gallons per Day) - Continued Year...
Design of Ensemble-Based Component Systems by Invariant Refinement
study aims at resource optimization, such as travel time, energy consumption, and parking lot-evolving resilient distributed systems that are composed of autonomous components has been partially addressed. INTRODUCTION Addressing the challenge of developing large-scale distributed autonomic and adaptive systems [26
Fuel and oxygen addition for metal smelting or refining process
Schlichting, M.R.
1994-11-22T23:59:59.000Z
A furnace for smelting iron ore and/or refining molten iron is equipped with an overhead pneumatic lance, through which a center stream of particulate coal is ejected at high velocity into a slag layer. An annular stream of nitrogen or argon enshrouds the coal stream. Oxygen is simultaneously ejected in an annular stream encircling the inert gas stream. The interposition of the inert gas stream between the coal and oxygen streams prevents the volatile matter in the coal from combusting before it reaches the slag layer. Heat of combustion is thus more efficiently delivered to the slag, where it is needed to sustain the desired reactions occurring there. A second stream of lower velocity oxygen can be delivered through an outermost annulus to react with carbon monoxide gas rising from slag layer, thereby adding still more heat to the furnace. 7 figs.
Wavelet Bi-frames with few Generators from Multivariate Refinable Functions
Ehler, Martin
Wavelet Bi-frames with few Generators from Multivariate Refinable Functions Martin Ehler Bin Han compactly supported wavelet bi-frames with few generators from almost any pair of compactly sup- ported multivariate refinable functions. In our examples, we focus on wavelet bi-frames whose primal and dual wavelets
Refining k-means by Bootstrap and Data Depth Aurora Torrente and Juan Romo
Romo, Juan
Refining k-means by Bootstrap and Data Depth Aurora Torrente and Juan Romo Departamento de Estad two simple, computationally fast methods that allow the refinement of the initial points of k-means to cluster a given data set. They are based on alternating k-means and the search of the deepest (most
Rapidly-Exploring Roadmaps: Weighing Exploration vs. Refinement in Optimal Motion Planning
North Carolina at Chapel Hill, University of
Rapidly-Exploring Roadmaps: Weighing Exploration vs. Refinement in Optimal Motion Planning Ron of already explored regions to find better paths. We present the rapidly- exploring roadmap (RRM), a new to explore further or to refine the explored space by adding edges to the current roadmap to find higher
To appear in EPTCS. A CSP account of Event-B refinement
Doran, Simon J.
To appear in EPTCS. A CSP account of Event-B refinement Steve Schneider Department of Computing a CSP account of Event-B refinement, with a treatment for the first time of splitting events and of anticipated events. To this end, we define a CSP seman- tics for Event-B and show how the different forms
FDR3 --A Modern Refinement Checker for CSP Thomas Gibson-Robinson, Philip Armstrong,
Oxford, University of
FDR3 -- A Modern Refinement Checker for CSP Thomas Gibson-Robinson, Philip Armstrong, Alexandre.roscoe}@cs.ox.ac.uk Abstract. FDR3 is a complete rewrite of the CSP refinement checker FDR2, incorporating a significant number describe the new algorithm that FDR3 uses to construct its internal representation of CSP processes
FDR3 --A Modern Refinement Checker for CSP Thomas Gibson-Robinson, Philip Armstrong,
Oxford, University of
FDR3 -- A Modern Refinement Checker for CSP Thomas Gibson-Robinson, Philip Armstrong, Alexandre.roscoe}@cs.ox.ac.uk Abstract. FDR3 is a complete rewrite of the CSP refinement checker FDR2, incorporating a significant number describe the new algorithm that FDR3 uses to construct its in- ternal representation of CSP processes
Don't care in SMT--Building flexible yet efficient abstraction/refinement solvers
Leucker, Martin
Don't care in SMT--Building flexible yet efficient abstraction/refinement solvers Andreas Bauer Satisfiability Modulo Theories (SMT) solver for a wide range of theories. Our method follows the abstrac- tion/refinement approach to simplify the implementation of custom SMT solvers. The expected performance penalty
Don't care in SMT---Building flexible yet efficient abstraction/refinement solvers
Leucker, Martin
Don't care in SMT---Building flexible yet efficient abstraction/refinement solvers Andreas Bauer an efficient Satisfiability Modulo Theories (SMT) solver for a wide range of theories. Our method follows the abstrac tion/refinement approach to simplify the implementation of custom SMT solvers. The expected
Aspects of Western Refining, Inc.'s Proposed Acquisition of Giant Industries, Inc.
Reports and Publications (EIA)
2006-01-01T23:59:59.000Z
Presentation of company-level, non-proprietary data and relevant aggregate data for U.S. refinery capacity and gasoline marketing of Western Refining and Giant Industries to inform discussions of Western Refining Inc.'s proposed acquisition of Giant Industries Inc. for a total of $1.5 billion, which was announced August 28, 2006.
Shepherd, Jason (Albuquerque, NM); Mitchell, Scott A. (Albuquerque, NM); Jankovich, Steven R. (Anaheim, CA); Benzley, Steven E. (Provo, UT)
2007-05-15T23:59:59.000Z
The present invention provides a meshing method, called grafting, that lifts the prior art constraint on abutting surfaces, including surfaces that are linking, source/target, or other types of surfaces of the trunk volume. The grafting method locally modifies the structured mesh of the linking surfaces allowing the mesh to conform to additional surface features. Thus, the grafting method can provide a transition between multiple sweep directions extending sweeping algorithms to 23/4-D solids. The method is also suitable for use with non-sweepable volumes; the method provides a transition between meshes generated by methods other than sweeping as well.
Adaptive Street Lighting Controls
Broader source: Energy.gov [DOE]
This two-part DOE Municipal Solid-State Street Lighting Consortium webinar focused on LED street lighting equipped with adaptive control components. In Part I, presenters Amy Olay of the City of...
Climate Change Adaptation Planning
Office of Energy Efficiency and Renewable Energy (EERE)
This course provides an introduction to planning for climate change impacts, with examples of tribes that have been going through the adaptation planning process. The course is intended for tribal...
Verification of Unstructured Mesh Capabilities in MCNP6 for Reactor Physics Problems
Burke, Timothy P. [Los Alamos National Laboratory; Martz, Roger L. [Los Alamos National Laboratory; Kiedrowski, Brian C. [Los Alamos National Laboratory; Martin, William R. [Los Alamos National Laboratory
2012-08-22T23:59:59.000Z
New unstructured mesh capabilities in MCNP6 (developmental version during summer 2012) show potential for conducting multi-physics analyses by coupling MCNP to a finite element solver such as Abaqus/CAE[2]. Before these new capabilities can be utilized, the ability of MCNP to accurately estimate eigenvalues and pin powers using an unstructured mesh must first be verified. Previous work to verify the unstructured mesh capabilities in MCNP was accomplished using the Godiva sphere [1], and this work attempts to build on that. To accomplish this, a criticality benchmark and a fuel assembly benchmark were used for calculations in MCNP using both the Constructive Solid Geometry (CSG) native to MCNP and the unstructured mesh geometry generated using Abaqus/CAE. The Big Ten criticality benchmark [3] was modeled due to its geometry being similar to that of a reactor fuel pin. The C5G7 3-D Mixed Oxide (MOX) Fuel Assembly Benchmark [4] was modeled to test the unstructured mesh capabilities on a reactor-type problem.
Discriminative Adaptive Training and Bayesian Inference for
de Gispert, AdriĂ
adaptation is a standard part of many speech recognition systems. This process requires some adaptation data
Yano, Masayuki, Ph. D. Massachusetts Institute of Technology
2012-01-01T23:59:59.000Z
Improving the autonomy, efficiency, and reliability of partial differential equation (PDE) solvers has become increasingly important as powerful computers enable engineers to address modern computational challenges that ...
Boyer, Edmond
-Einstein condensates Ionut Danaila,a,b , FrÂ´edÂ´eric Hechta,b aUPMC Univ Paris 06, UMR 7598, Laboratoire Jacques Abstract Numerical computations of stationary states of fast-rotating Bose-Einstein condensates require-Einstein condensate, vortex, Sobolev gradient, descent method. 1. Introduction Recent research efforts in the field
Recanati, Catherine
ÂEinstein condensates Ionut Danaila #,a,b , Frâ??edâ??eric Hecht a,b a UPMC Univ Paris 06, UMR 7598, Laboratoire Jacques Abstract Numerical computations of stationary states of fastÂrotating BoseÂEinstein condensates requireÂEinstein condensate, vortex, Sobolev gradient, descent method. 1. Introduction Recent research e#orts in the field
Organizational Adaptation Kathleen M. Carley
Sadeh, Norman M.
Organizational Adaptation Kathleen M. Carley Dept. of Social and Decision Sciences Carnegie Mellon: Kathleen M. Carley, 1998, "Organizational Adaptation." Annals of Operations Research. 75: 25-47. #12;Organizational Adaptation A computational model of organizational adaptation in which change occurs at both
Chow, Fotini Katopodes
reflect off grid refinement interfaces, specifically on the outflow boundary from a fine to a coarse grid reflection off grid refinement interfaces by forcing the filter-resolved scale on a fine grid to equal
Development of Au-Ag nanowire mesh fabrication by UV-induced approach
Saggar, Siddhartha [Laboratory for Molecular Photonics and Electronics, Department of Physics, National Institute of Technology, Calicut, Kerala, India and School of Nanoscience and Technology, National Institute of Technology, Calicut, Kerala (India); Predeep, Padmanabhan, E-mail: predeep@nitc.ac.in
2014-10-15T23:59:59.000Z
In an attempt to overcome the limitations of the presently prevailing transparent conducting electrode (TCE) - indium tin oxide (ITO) - many materials have been considered for replacing ITO. Recently, a novel method has been reported for the synthesis of Au-Ag nanowire (NW) mesh, and tested successfully for organic-light-emitting-diodes (OLEDs). It employs UV-induced reduction of gold- and silver- precursors to form Au-Ag NW mesh. In this report, Au-Ag NW mesh thin films are synthesized on glass substrates with an objective for use as facing-electrode for Organic Photovoltaics. Various issues and factors affecting the fabrication-process have been improved, and are also discussed here. The electrode showed good transmitivity, of around 95% (excluding that of glass substrate). The advantage of the technique is its simple processing method and cost-effectiveness.
Utah, University of
on the surface of the scalp and the geometry and conductivity properties within the head, calculate the current and potential fields within the brain through an inverse procedure. To test these methods, we have constructed several finite element head models from magnetic resonance images (MRI) of a patient. The finite element
William J. Gutowski; Joseph M. Prusa, Piotr K. Smolarkiewicz
2012-04-09T23:59:59.000Z
This project had goals of advancing the performance capabilities of the numerical general circulation model EULAG and using it to produce a fully operational atmospheric global climate model (AGCM) that can employ either static or dynamic grid stretching for targeted phenomena. The resulting AGCM combined EULAG's advanced dynamics core with the 'physics' of the NCAR Community Atmospheric Model (CAM). Effort discussed below shows how we improved model performance and tested both EULAG and the coupled CAM-EULAG in several ways to demonstrate the grid stretching and ability to simulate very well a wide range of scales, that is, multi-scale capability. We leveraged our effort through interaction with an international EULAG community that has collectively developed new features and applications of EULAG, which we exploited for our own work summarized here. Overall, the work contributed to over 40 peer-reviewed publications and over 70 conference/workshop/seminar presentations, many of them invited.
Moving mesh partial differential equations (MMPDEs) based upon the equidistribution principle
Huang, Weizhang; Ren, Yuhe; Russell, Robert D.
1994-06-01T23:59:59.000Z
, ft Ot of fixed, Of Of Of Ox dt Ot fixed= Oz tfixed Ot fixed + fixed for an arbitrary function f f(z, t) f(z(, t), t). Suppose that a uniform mesh is given on the computational domain by (3) i -, 0, 1,...,n, where n is a certain positive integer...) satisfies the QSEP is completely determined from the initial mesh by this relationship. 3.2. (MMPDE2). The analysis for (MMPDE2) is similar to that of (MMPDE1). From a linear stability analysis, we have (49) 5x(, t) e-5 M(x(, 0), 0) 6x(, 0).M(x(,t),t) D ow...
M Moodley; N K Padayachee; V Govender
Due to the successful use of the Saccharoflex 2000 reflectance measurement instrument on the estimation of refined sugar colour elsewhere in the world, it was decided by Tongaat-Hulett Sugar to evaluate the instrument at the refinery in Durban. Tests were carried out on first, second, third and fourth refined sugars, the results of which showed a good correlation between the ICUMSA colour measurement and the reflectance reading obtained from the Saccharoflex 2000. The instrument offers a number of advantages, the main one being that a refined sugar colour value can be obtained in less than a minute. The refinery has therefore purchased one for process control.
Influence of Aluminum Content on Grain Refinement and Strength of AZ31 Magnesium GTA Weld Metal
Babu, N. Kishore [Singapore Institute of Manufacturing Technology; Cross, Carl E. [Los Alamos National Laboratory
2012-06-28T23:59:59.000Z
The goal is to characterize the effect of Al content on AZ31 weld metal, the grain size and strength, and examine role of Al on grain refinement. The approach is to systematically vary the aluminum content of AZ31 weld metal, Measure average grain size in weld metal, and Measure cross-weld tensile properties and hardness. Conclusions are that: (1) increased Al content in AZ31 weld metal results in grain refinement Reason: higher undercooling during solidification; (2) weld metal grain refinement resulted in increased strength & hardness Reason: grain boundary strengthening; and (3) weld metal strength can be raised to wrought base metal levels.
http://rcc.its.psu.edu/hpc A Numerical Investigation on the Interplay Among Geometry, Meshes, and
BjĂ¸rnstad, Ottar Nordal
other combinations - Total time: RR quality metric => IMR quality metric Experiment 2: - Effect Objective: To study the effect the choice of mesh quality metric, preconditioner, and sparse linear solver: Boundary condition used is the Dirichlet boundary condition (u=0). Mesh Quality Metrics: Four different
Implementing TCP Flow-Level Fairness Using 802.11e in a Multi-Radio Mesh Testbed
Duffy, Ken
, CSMA/CA, TCP, test-bed I. Introduction The problems faced by TCP in 802.11 multi-hop mesh wireless with multi-radio relay stations built us- ing commodity hardware. The proposed approach creates present whenever TCP flows are aggregated at a relay hop in a mesh network. This leads to queueing
Feasibility Study of Single-Photon Counting Using a Fine-mesh Phototube for an Aerogel Readout
R. Enomoto et al
1994-12-14T23:59:59.000Z
The fine-mesh phototube is one type of photodetector which can be used under a strong magnetic field. For an aerogel readout, the single-photon detection efficiency should be close to 100\\% in order to identify particle species. We carried out a feasibility study of single-photon counting using fine-mesh phototubes, and obtained a possible solution.
State of heavy oil production and refining in California
Olsen, D.K.; Ramzel, E.B. [BDM-Oklahoma, Inc., Bartlesville, OK (United States)
1995-12-31T23:59:59.000Z
California is unique in the United States because it has the largest heavy oil (10{degrees} to 20{degrees}API gravity) resource, estimated to be in excess of 40 billion barrels. Of the current 941,543 barrels/day of oil produced in California (14% of the U.S. total), 70% or 625,312 barrels/day is heavy oil. Heavy oil constituted only 20% of California`s oil production in the early 1940s, but development of thermal oil production technology in the 1960s allowed the heavy industry to grow and prosper to the point where by the mid-1980s, heavy oil constituted 70% of the state`s oil production. Similar to the rest of the United States, light oil production in the Los Angeles Basin, Coastal Region, and San Joaquin Valley peaked and then declined at different times throughout the past 30 years. Unlike other states, California developed a heavy oil industry that replaced declining light oil production and increased the states total oil production, despite low heavy oil prices, stringent environmental regulations and long and costly delays in developing known oil resources. California`s deep conversion refineries process the nation`s highest sulfur, lowest API gravity crude to make the cleanest transportation fuels available. More efficient vehicles burning cleaner reformulated fuels have significantly reduced the level of ozone precursors (the main contributor to California`s air pollution) and have improved air quality over the last 20 years. In a state where major oil companies dominate, the infrastructure is highly dependent on the 60% of ANS production being refined in California, and California`s own oil production. When this oil is combined with the small volume of imported crude, a local surplus of marketed oil exists that inhibits exploitation of California`s heavy oil resources. As ANS production declines, or if the export restrictions on ANS sales are lifted, a window of opportunity develops for increased heavy oil production.
Adaptive Medical Information Delivery Combining User, Task and Situation Models
., in their model for adaptive hypermedia AHAM [2], distinguish contentadaptation from link adaptation
Hou, Y. Thomas
Abstract Wireless mesh networks have emerged as a promising technology for providing ubiquitous for multiple-description video communications in wireless mesh networks. We aim to answer the following in wireless mesh 190890-8044/08/$25.00 © 2008 IEEE TT IEEE Network · January/February 2008 Shiwen Mao, Auburn
Table 9. U.S. Refiner Conventional Motor Gasoline Volumes by...
U.S. Energy Information Administration (EIA) Indexed Site
5.7 5.9 4.4 12.9 NA 17.3 See footnotes at end of table. 9. U.S. Refiner Conventional Motor Gasoline Volumes by Grade and Sales Type 18 Energy Information Administration ...
Table 10. U.S. Refiner Oxygenated Motor Gasoline Prices by...
U.S. Energy Information Administration (EIA) Indexed Site
98.0 98.0 86.6 75.0 - 80.1 See footnotes at end of table. 10. U.S. Refiner Oxygenated Motor Gasoline Prices by Grade and Sales Type 20 Energy Information Administration ...
Table 13. U.S. Refiner Reformulated Motor Gasoline Volumes by...
U.S. Energy Information Administration (EIA) Indexed Site
3.3 3.4 7.9 3.3 W 11.3 See footnotes at end of table. 13. U.S. Refiner Reformulated Motor Gasoline Volumes by Grade and Sales Type 26 Energy Information Administration ...
Table 12. U.S. Refiner Reformulated Motor Gasoline Prices by...
U.S. Energy Information Administration (EIA) Indexed Site
92.4 92.1 83.7 74.1 W 80.9 See footnotes at end of table. 12. U.S. Refiner Reformulated Motor Gasoline Prices by Grade and Sales Type 24 Energy Information Administration ...
Table 8. U.S. Refiner Conventional Motor Gasoline Prices by...
U.S. Energy Information Administration (EIA) Indexed Site
87.4 86.9 78.3 68.5 W 70.8 See footnotes at end of table. 8. U.S. Refiner Conventional Motor Gasoline Prices by Grade and Sales Type 16 Energy Information Administration ...
Table 12. U.S. Refiner Reformulated Motor Gasoline Prices by...
U.S. Energy Information Administration (EIA) Indexed Site
92.8 92.5 84.0 72.5 W 80.7 See footnotes at end of table. 12. U.S. Refiner Reformulated Motor Gasoline Prices by Grade and Sales Type 24 Energy Information Administration ...
Table 8. U.S. Refiner Conventional Motor Gasoline Prices by...
U.S. Energy Information Administration (EIA) Indexed Site
88.4 87.8 80.1 70.0 NA 72.6 See footnotes at end of table. 8. U.S. Refiner Conventional Motor Gasoline Prices by Grade and Sales Type 16 Energy Information Administration ...
Table 10. U.S. Refiner Oxygenated Motor Gasoline Prices by...
U.S. Energy Information Administration (EIA) Indexed Site
94.0 93.9 83.2 73.8 - 79.3 See footnotes at end of table. 10. U.S. Refiner Oxygenated Motor Gasoline Prices by Grade and Sales Type 20 Energy Information Administration ...
Table 13. U.S. Refiner Reformulated Motor Gasoline Volumes by...
U.S. Energy Information Administration (EIA) Indexed Site
3.6 3.7 7.9 3.1 W 11.0 See footnotes at end of table. 13. U.S. Refiner Reformulated Motor Gasoline Volumes by Grade and Sales Type 26 Energy Information Administration ...
Table 9. U.S. Refiner Conventional Motor Gasoline Volumes by...
U.S. Energy Information Administration (EIA) Indexed Site
5.7 5.9 3.9 12.7 W 16.6 See footnotes at end of table. 9. U.S. Refiner Conventional Motor Gasoline Volumes by Grade and Sales Type 18 Energy Information Administration ...
Process for solvent refining of coal using a denitrogenated and dephenolated solvent
Garg, Diwakar (Macungie, PA); Givens, Edwin N. (Bethlehem, PA); Schweighardt, Frank K. (Allentown, PA)
1984-01-01T23:59:59.000Z
A process is disclosed for the solvent refining of non-anthracitic coal at elevated temperatures and pressure in a hydrogen atmosphere using a hydrocarbon solvent which before being recycled in the solvent refining process is subjected to chemical treatment to extract substantially all nitrogenous and phenolic constituents from the solvent so as to improve the conversion of coal and the production of oil in the solvent refining process. The solvent refining process can be either thermal or catalytic. The extraction of nitrogenous compounds can be performed by acid contact such as hydrogen chloride or fluoride treatment, while phenolic extraction can be performed by caustic contact or contact with a mixture of silica and alumina.
Table A2. Refiner/Reseller Prices of Aviation Fuels, Propane...
U.S. Energy Information Administration (EIA) Indexed Site
- W 73.5 See footnotes at end of table. A2. RefinerReseller Prices of Aviation Fuels, Propane, and Kerosene, by PAD District, 1983-Present Energy Information Administration ...
Economic impact of the European Union Emission Trading Scheme : evidence from the refining sector
Lacombe, Romain H
2008-01-01T23:59:59.000Z
I study the economic impact of the European Union Emission Trading Scheme (EU ETS) on the refining industry in Europe. I contrast previous ex-ante studies with the lessons from a series of interviews I conducted with ...
Tronrud, Dale E.; Berkholz, Donald S.; Karplus, P. Andrew (Oregon State U.)
2010-07-02T23:59:59.000Z
The major macromolecular crystallographic refinement packages restrain models to ideal geometry targets defined as single values that are independent of molecular conformation. However, ultrahigh-resolution X-ray models of proteins are not consistent with this concept of ideality and have been used to develop a library of ideal main-chain bond lengths and angles that are parameterized by the {phi}/{psi} angle of the residue [Berkholz et al. (2009), Structure, 17, 1316-1325]. Here, it is first shown that the new conformation-dependent library does not suffer from poor agreement with ultrahigh-resolution structures, whereas current libraries have this problem. Using the TNT refinement package, it is then shown that protein structure refinement using this conformation-dependent library results in models that have much better agreement with library values of bond angles with little change in the R values. These tests support the value of revising refinement software to account for this new paradigm.
Table 46. Refiner No. 2 Distillate, Diesel Fuel, and Fuel Oil...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
132.9 1,418.3 See footnotes at end of table. 46. Refiner No. 2 Distillate, Diesel Fuel, and Fuel Oil Volumes by PAD District and State Energy Information Administration ...
Table 46. Refiner No. 2 Distillate, Diesel Fuel, and Fuel Oil...
Gasoline and Diesel Fuel Update (EIA)
839.2 135.0 1,251.9 See footnotes at end of table. 46. Refiner No. 2 Distillate, Diesel Fuel, and Fuel Oil Volumes by PAD District and State Energy Information Administration ...
Table A3. Refiner/Reseller Prices of Distillate and Residual...
Gasoline and Diesel Fuel Update (EIA)
A3. RefinerReseller Prices of Distillate and Residual Fuel Oils, by PAD District, 1983-Present (Cents per Gallon Excluding Taxes) Geographic Area Year No. 1 Distillate No. 2...
Optimized Execution of Action Chains through Subgoal Refinement Freek Stulp and Michael Beetz
Cremers, Daniel
Optimized Execution of Action Chains through Subgoal Refinement Freek Stulp and Michael Beetz, Germany {stulp,beetz}@in.tum.de Abstract In this paper we propose a novel computation model
Refine your search Select options from the menu on the left hand
Yener, Aylin
://psu.summon.serialssolutions.comhttp://psu.summon.serialssolutions.com F I N A L LY : RESEARCH AS EASYAS 1-2-3 #12;1 Enter search term into search box. 2 Refine results relevant articles were published in that year. Include or Exclude subject terms from your searchRefine your search Select options from the menu on the left hand side of the results screen
Adaptation and adaptability : expectant design for resilience in coastal urbanity
Ruskeepää, Laura A. Delaney (Laura Ashley Delaney)
2011-01-01T23:59:59.000Z
What is the nature of and possibility for urban resiliency through adaptation? Adaptation implies responsiveness to phenomena that are disruptive to a system's functioning; it is a willful evolution in response to changed ...
An Effective Mesh-Generation Strategy for Image Representation Using Data-Dependent Triangulation
Adams, Michael D.
, Victoria, BC, Canada pingli@ece.uvic.ca and mdadams@ece.uvic.ca August 2013 Ping Li and Michael D. Adams Ping Li and Michael D. Adams Department of Electrical and Computer Engineering University of Victoria (UVic) PacRim 2013 August 2013 1 #12;Outline 1 Motivation 2 Triangle Meshes for Image Representation 3
Paris-Sud XI, Université de
to internal combustion engines D. Kaha,3 , O. Emreb,c,d,2 , Q. H. Trand , S. de Chaisemartind, , S. Jayd , F meshes. Extending the approach to internal combustion engine and fuel injection requires solving two simulations with spray in internal combustion engines have become a critical target in the automotive industry
Survivable Smart Grid Communication: Smart-Meters Meshes to the Rescue
Tague, Patrick
Survivable Smart Grid Communication: Smart-Meters Meshes to the Rescue Arjun P. Athreya and Patrick flattening process. This process involves smart-meters and other disaster surviving elements of higher system as a function of outage area, smart-meter density and smart-meter's neighborhood size. The results from
PMR: Point to Mesh Rendering, A Feature-Based Approach Tamal K. Dey James Hudson
Dey, Tamal Krishna
PMR: Point to Mesh Rendering, A Feature-Based Approach Tamal K. Dey James Hudson The Ohio State. Point based rendering methods have been shown effective for this task. Building on this paradigm we introduce the PMR system which uses a hierarchy both in points and triangles for rendering. This hierarchy
Calculation of eddy currents in moving structures by a sliding mesh-nite element method
Buffa, Annalisa
Calculation of eddy currents in moving structures by a sliding mesh- nite element method A. Bu of eddy currents in non-stationary structures. Both 2D and 3D models are considered. The approximation. An implicit Euler scheme is used to discretize in time. Key words { eddy currents, nite element approxima
M.Sc.-thesis research Robustness improvement of polyhedral mesh method for airbag
Vuik, Kees
M.Sc.-thesis research Robustness improvement of polyhedral mesh method for airbag deployment. Project background A madymo airbag deployment simulation is a coupled simulation of the airbag fabric dynamics (structural equations of motion) and the fluid inside the airbag (Euler equations of fluid motion
Use of Carbon Mesh Anodes and the Effect of Different Pretreatment
Use of Carbon Mesh Anodes and the Effect of Different Pretreatment Methods on Power Production, China, and Department of Civil and Environmental Engineering, Penn State University, 231Q Sackett electrode spacing improves power generation. Carbon cloth and carbon paper materials typically used
Plotkin, Joshua B.
orienting facets in polygon meshes by minimizing the Dirichlet energy of generalized winding numbers. While based on the Dirichlet energy of the generalized winding number. Our motivation came from the fact Dirichlet energy of the corresponding generalized winding number. 2 Method 2.1 Patch extraction
Generating 3D volumetric meshes of internal and external fruit Mikolaj Cieslak1,2
Paris-Sud XI, Université de
Generating 3D volumetric meshes of internal and external fruit structure Mikolaj Cieslak1 Godin2 and Nadia Bertin1 1 INRA, UR 1115 Plantes et Systčmes de Culture Horticoles, Domaine St Paul, Site Agroparc, F-84914 Avignon Cedex 9, France 2 CIRAD/INRIA/INRA, Virtual Plants INRIA Team, UMR AGAP
A Mesh-based Robust Topology Discovery Algorithm for Hybrid Wireless Networks
Birman, Kenneth P.
A Mesh-based Robust Topology Discovery Algorithm for Hybrid Wireless Networks Ranveer CHANDRA˘ @research.att.com Abstract Wireless networks in home, office and sensor applications consist of nodes by a wireline network. Topology information of the wireless network at these powerful nodes can be used
Blackledge, Todd
Mesh Width Influences Prey Retention in Spider Orb Webs Todd A. Blackledge & Jacquelyn M. Zevenbergen Department of Biology, The University of Akron, Akron, OH, USA Introduction Orb webs depend upon threads, the sticky spirals of orb webs perform two important functions during prey cap- ture. First
Kolner, Brian H.
1 Intelligent Network-Layer Management for Wireless Mesh Networks: Dynamic Tuning of a Reactive Routing Protocol Dan Marconett, Minsoo Lee, Xiaohui Ye and S. J. Ben Yoo Dept. of Electrical and Computer learning to dynamically modify reactive routing protocol parameters in real-time, to better facilitate
Chirathadam, Thomas
2012-12-10T23:59:59.000Z
pads and a smooth top foil. The analysis models the top foil as a 2D finite element (FE) shell supported uniformly by a metal mesh under-layer. The solution of the structural FE model coupled with a gas film model, governed by the Reynolds equation...
I N F O R M A T I K Neural Meshes: Statistical Learning
Jeong, Won-Ki
classic papers like [21] which has shown the potential of a signal- theoretic approach, the majority' $ ' $ #12; I N F O R M A T I K © ¨ Neural Meshes: Statistical Learning Methods in Surface learning process. The topology is learned through statistics based op- erations which create boundaries
Spacefilling curves for 2simplicial meshes created with bisections and reflections
Eindhoven, Technische Universiteit
computational 2meshes which can be very e#ciently loadbalanced with the use of a spacefilling curve. Keywords: Grid generation, space filling curve, load balancing Mathematics Subject Classification 2000: 65M the elements in curvetraversal order, and the required loadbalance redistribution amounts to a possible
Identifying Pollution Attackers in Network-Coding Enabled Wireless Mesh Networks
Lui, John C.S.
Identifying Pollution Attackers in Network-Coding Enabled Wireless Mesh Networks Yongkun Li: cslui@cse.cuhk.edu.hk Abstract--Pollution attack is a severe security problem in network-coding enabled spreading of polluted packets to deplete network resources. We address this security problem even when
Global optimization-based deformable meshes for surface extraction from medical
Neumaier, Arnold
(GAGR). By global optimization of the energy of the de- formable models, we are capable of reducingGlobal optimization-based deformable meshes for surface extraction from medical images Jussi Tohka, Dual surface minimization (DSM) and a hybrid of real-coded genetic algorithms and a greedy algorithm
Light-Hierarchy: The Optimal Structure for Multicast Routing in WDM Mesh Networks
Paris-Sud XI, Université de
Light-Hierarchy: The Optimal Structure for Multicast Routing in WDM Mesh Networks Fen Zhou on the same wavelength, the light-tree structure was always thought to be optimal for multicast routing session, an MI node could be crosswise visited more than once to switch a light signal towards several
Multicast Routing and Wavelength Assignment in WDM Mesh Networks with Sparse Splitting
Paris-Sud XI, Université de
separately by heuristic algorithms, or formulated as an Integer Linear Programming (ILP) and solved onceMulticast Routing and Wavelength Assignment in WDM Mesh Networks with Sparse Splitting Fen Zhou.cousin@irisa.fr Abstract--In this paper routing and wavelength assignment for supporting multicast traffic is investigated
Assignment of Roles and Channels for a Multichannel MAC in Wireless Mesh Networks
Paris-Sud XI, Université de
MILP (Mixed Integer Linear Programming) problem. Its solution leads to the optimal assignment of roles for constructing such a molecular structure through a MILP (Mixed Integer Linear Programming) formulationAssignment of Roles and Channels for a Multichannel MAC in Wireless Mesh Networks Fabrice Theoleyre
A network-coding based event diffusion protocol for wireless mesh networks
Beraldi, Roberto
of mobile and/or portable wireless devices (e.g. WiFi-enabled smart phones, mobile TV devices, etc.) which. The grid topology arising from a metropolitan deployment of a WMN [11], LeSubscribe [16]. However, while over a Manhattan like city model, see [1], in which mesh routers can be considered as approximately
3D Harmonic Mapping and Tetrahedral Meshing of Brain Imaging Data
Thompson, Paul
3D Harmonic Mapping and Tetrahedral Meshing of Brain Imaging Data Yalin Wang1 , Xianfeng Gu2 , Paul algorithm finds a harmonic map from a 3-manifold to a 3D solid sphere and the second is a novel sphere of magnetic resonance images (MRI). A heat flow method is used to solve the volumetric harmonic mapping
CONVERGENCE OF THE HAMILTONIAN PARTICLE-MESH METHOD FOR BAROTROPIC FLUID FLOW
Oliver, Marcel
AND MARCEL OLIVER Abstract. We prove convergence of the Hamiltonian Particle-Mesh (HPM) method, initially, and a StrangFix condition of order 3 for the local par- tition of unity kernel, the HPM method converges limiting case of the HPM algorithm and we find that the respective rates of convergence are comparable
On the rate of convergence of the Hamiltonian particle-mesh method
Oliver, Marcel
. The Hamiltonian Particle-Mesh (HPM) method is a particle-in-cell method for compressible fluid flow with Hamiltonian structure. We present a numer- ical short-time study of the rate of convergence of HPM in terms available theoretical estimates. Our results indicate that HPM performs best when the number of particles
The Effect of Vertex Reordering on 2D Local Mesh Optimization Efficiency
Shontz, Suzanne M.
. To numerically solve the equations, finite element, finite volume, and other PDE-discretization methods-1318, pknupp@sandia.gov 1 Local Mesh Optimization Many applications in computational science such as heat transfer, advection- diffusion, and fluid dynamics numerically solve partial differential equations
Hierarchical Extraction of Iso-Surfaces with Semi-Regular Meshes Kai Hormann
Hormann, Kai
Hierarchical Extraction of Iso-Surfaces with Semi-Regular Meshes Kai Hormann Ulf Labsik Martin and final result of our hierarchical iso-surface extraction algorithm. Abstract In this paper we present a novel approach to iso-surface extrac- tion which is based on a multiresolution volume data
Adaptive sequential controller
El-Sharkawi, Mohamed A. (Renton, WA); Xing, Jian (Seattle, WA); Butler, Nicholas G. (Newberg, OR); Rodriguez, Alonso (Pasadena, CA)
1994-01-01T23:59:59.000Z
An adaptive sequential controller (50/50') for controlling a circuit breaker (52) or other switching device to substantially eliminate transients on a distribution line caused by closing and opening the circuit breaker. The device adaptively compensates for changes in the response time of the circuit breaker due to aging and environmental effects. A potential transformer (70) provides a reference signal corresponding to the zero crossing of the voltage waveform, and a phase shift comparator circuit (96) compares the reference signal to the time at which any transient was produced when the circuit breaker closed, producing a signal indicative of the adaptive adjustment that should be made. Similarly, in controlling the opening of the circuit breaker, a current transformer (88) provides a reference signal that is compared against the time at which any transient is detected when the circuit breaker last opened. An adaptive adjustment circuit (102) produces a compensation time that is appropriately modified to account for changes in the circuit breaker response, including the effect of ambient conditions and aging. When next opened or closed, the circuit breaker is activated at an appropriately compensated time, so that it closes when the voltage crosses zero and opens when the current crosses zero, minimizing any transients on the distribution line. Phase angle can be used to control the opening of the circuit breaker relative to the reference signal provided by the potential transformer.
CONTRIBUTED Adaptive Stochastic Control
Powell, Warren B.
sources, many forms of energy storage, and microgrid management (see Fig. 1). Computationally, controlling of distributed generation and storage within the Smart Grid. KEYWORDS | Adaptive stochastic control (ASC.g., factory assembly lines, petrochemical plants, and nuclear power plants). Below we describe
ON AN ADAPTIVE CONTROL ALGORITHM FOR ADAPTIVE OPTICS APPLICATIONS
ON AN ADAPTIVE CONTROL ALGORITHM FOR ADAPTIVE OPTICS APPLICATIONS MOODY T. CHU Abstract. The wavefront aberrations induced by atmospheric turbulence can severely degrade the performance of an optical imaging system. Adaptive optics refers to the process of removing unwanted wave front distortions
ON AN ADAPTIVE CONTROL ALGORITHM FOR ADAPTIVE OPTICS APPLICATIONS
ON AN ADAPTIVE CONTROL ALGORITHM FOR ADAPTIVE OPTICS APPLICATIONS MOODY T. CHU \\Lambda Abstract. The wavefront aberrations induced by atmospheric turbulence can severely degrade the performance of an optical imaging system. Adaptive optics refers to the process of removing unwanted wave front distortions
Adaptive Survey Design Andrew Sage
Carriquiry, Alicia
. Andrew Sage Iowa State University CSSM March 14, 2014 2 / 35 #12;Adaptive and Responsive Designs collection, although they may be revised during data collection. A responsive design is an adaptive design
Development of an Atmospheric Climate Model with Self-Adapting Grid and Physics
Penner, Joyce E. [University of Michigan] University of Michigan
2013-08-10T23:59:59.000Z
This project was targeting the development of a computational approach that would allow resolving cloud processes on small-scales within the framework of the most recent version of the NASA/NCAR Finite-Volume Community Atmospheric Model (FVCAM). The FVCAM is based on the multidimensional Flux-Form Semi-Lagrangian (FFSL) dynamical core and uses a ?vertically Lagrangian? finite-volume (FV) representation of the model equations with a mass-conserving re-mapping algorithm. The Lagrangian coordinate requires a remapping of the Lagrangian volume back to Eulerian coordinates to restore the original resolution and keep the mesh from developing distortions such as layers with overlapping interfaces. The main objectives of the project were, first, to develop the 3D library which allows refinement and coarsening of the model domain in spherical coordinates, and second, to develop a non-hydrostatic code for calculation of the model variables within the refined areas that could be seamlessly incorporated with the hydrostatic finite volume dynamical core when higher resolution is wanted. We also updated the aerosol simulation model in CAM in order to ready the model for the treatment of aerosol/cloud interactions.
Climate Change, Adaptation, and Development
Cole, Daniel H.
2008-01-01T23:59:59.000Z
Climate Change, Adaptation, and Development Daniel H. Cole*THE COSTS OF CLIMATE CHANGE . ADAPTATIONCONVENTION ON CLIMATE CHANGE . IV. A.
ON ADAPTIVE SAMPLING Philippe Flajolet
Flajolet, Philippe
. We analyze the storage/accuracy trade--off of an adaptive sampling algorithm due to Wegman that makes. Wegman [11] has proposed an interesting alternative solution to that problem based on Adaptive Sampling 4. 2 Wegman's Adaptive Sampling Method The problem discussed here is the following. We are given
Adaptive control for accelerators
Eaton, Lawrie E. (Los Alamos, NM); Jachim, Stephen P. (Los Alamos, NM); Natter, Eckard F. (Santa Fe, NM)
1991-01-01T23:59:59.000Z
An adaptive feedforward control loop is provided to stabilize accelerator beam loading of the radio frequency field in an accelerator cavity during successive pulses of the beam into the cavity. A digital signal processor enables an adaptive algorithm to generate a feedforward error correcting signal functionally determined by the feedback error obtained by a beam pulse loading the cavity after the previous correcting signal was applied to the cavity. Each cavity feedforward correcting signal is successively stored in the digital processor and modified by the feedback error resulting from its application to generate the next feedforward error correcting signal. A feedforward error correcting signal is generated by the digital processor in advance of the beam pulse to enable a composite correcting signal and the beam pulse to arrive concurrently at the cavity.
Sali, Andrej
for future refinements when applied wholesale, but is already capable of producing valuable insight when
Need for refining capacity creates opportunities for producers in Middle East
Ali, M.S.S. (Bahrain National Oil Co., Awali (Bahrain))
1994-07-11T23:59:59.000Z
Oil industry interest in refining has revived in the past few years in response to rising oil consumption. The trend creates opportunities, for countries in the Middle East, which do not own refining assets nearly in proportion to their crude oil reserved. By closing this gap between reserves and refining capacity, the countries can ease some of the instability now characteristic of the oil market. Some major oil producing countries have begun to move downstream. During the 1980s, Venezuela, Kuwait, Saudi Arabia, Libya, and other members of the Organization of Petroleum Exporting Countries acquired refining assets through direct total purchase or joint ventures. Nevertheless, the oil industry remains largely unintegrated, with the Middle East holding two thirds of worldwide oil reserves but only a small share downstream. As worldwide refining capacity swings from a period of surplus toward one in which the need for new capacity will be built. The paper discusses background of the situation, shrinking surplus, investment requirements, sources of capital, and shipping concerns.
Hogarty, T.F.; Lindstrom, P.M.
1986-10-01T23:59:59.000Z
It is alleged by some dealers that (major) refiners consistently sell their gasoline through directly operated stations at retail prices below the prices charged to resellers. The results of this examination, involving more than 2000 price comparisons, failed to reveal a single instance where the average monthly retail price at refiner operated stations was below the price charged resellers by refiners. This result obtained not only for all gasoline sales by major refiners, but also for specific grades of gasoline sold by all refiners. Moreover, a large majority of the average monthly price differentials were greater than 6 cents per gallon, and exceeded 10 cents per gallon in a significant number of instances. Thus, the data do not support the allegation of widespread ''below-cost'' selling by refiners through outlets which they own and operate. Therefore, the rationale offered for legislation mandating retail divorcement, or prohibiting ''below-cost'' is not supported by the evidence. 3 figs., 5 tabs.
Mckenna, Sean
2010-01-15T23:59:59.000Z
An experimental investigation exploring the use of wire mesh/hollow glass microsphere combination for use as thermal insulation was conducted with the aim to conclude whether or not it represents a superior insulation technology to those...
Dohrmann, C.R.; Heinstein, M.W.; Jung, J.; Key, S.W.
1999-01-01T23:59:59.000Z
This report documents a collection of papers on a family of uniform strain tetrahedral finite elements and their connection to different element types. Also included in the report are two papers which address the general problem of connecting dissimilar meshes in two and three dimensions. Much of the work presented here was motivated by the development of the tetrahedral element described in the report "A Suitable Low-Order, Eight-Node Tetrahedral Finite Element For Solids," by S. W. Key {ital et al.}, SAND98-0756, March 1998. Two basic issues addressed by the papers are: (1) the performance of alternative tetrahedral elements with uniform strain and enhanced uniform strain formulations, and (2) the proper connection of tetrahedral and other element types when two meshes are "tied" together to represent a single continuous domain.
On Modeling and Analysis of MIMO Wireless Mesh Networks with Triangular Overlay Topology
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Cao, Zhanmao; Wu, Chase Q.; Zhang, Yuanping; Shiva, Sajjan G.; Gu, Yi
2015-01-01T23:59:59.000Z
Multiple input multiple output (MIMO) wireless mesh networks (WMNs) aim to provide the last-mile broadband wireless access to the Internet. Along with the algorithmic development for WMNs, some fundamental mathematical problems also emerge in various aspects such as routing, scheduling, and channel assignment, all of which require an effective mathematical model and rigorous analysis of network properties. In this paper, we propose to employ Cartesian product of graphs (CPG) as a multichannel modeling approach and explore a set of unique properties of triangular WMNs. In each layer of CPG with a single channel, we design a node coordinate scheme thatmore »retains the symmetric property of triangular meshes and develop a function for the assignment of node identity numbers based on their coordinates. We also derive a necessary-sufficient condition for interference-free links and combinatorial formulas to determine the number of the shortest paths for channel realization in triangular WMNs.« less
Automating crystallographic structure solution and refinement of protein–ligand complexes
Echols, Nathaniel, E-mail: nechols@lbl.gov; Moriarty, Nigel W., E-mail: nechols@lbl.gov; Klei, Herbert E.; Afonine, Pavel V. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8235 (United States); Bunkóczi, Gábor [University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Cambridge CB2 0XY (United Kingdom); Headd, Jeffrey J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8235 (United States); McCoy, Airlie J.; Oeffner, Robert D.; Read, Randy J. [University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Cambridge CB2 0XY (United Kingdom); Terwilliger, Thomas C. [Los Alamos National Laboratory, Los Alamos, NM 87545-0001 (United States); Adams, Paul D., E-mail: nechols@lbl.gov [Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8235 (United States); University of California at Berkeley, Berkeley, CA 94720-1762 (United States)
2014-01-01T23:59:59.000Z
A software system for automated protein–ligand crystallography has been implemented in the Phenix suite. This significantly reduces the manual effort required in high-throughput crystallographic studies. High-throughput drug-discovery and mechanistic studies often require the determination of multiple related crystal structures that only differ in the bound ligands, point mutations in the protein sequence and minor conformational changes. If performed manually, solution and refinement requires extensive repetition of the same tasks for each structure. To accelerate this process and minimize manual effort, a pipeline encompassing all stages of ligand building and refinement, starting from integrated and scaled diffraction intensities, has been implemented in Phenix. The resulting system is able to successfully solve and refine large collections of structures in parallel without extensive user intervention prior to the final stages of model completion and validation.
t s + t w m 2D Square Mesh with Wraparound
Zhang, Jun
t s + t w m 2D Square Mesh with Wraparound: 3.5 AlltoAll Personalized Communication 0 1 2 3 4 7 5 of the messages t s 3.5 AlltoAll Personalized Communication the alltoall broadcast on a hypercube 3.5 AlltoAll Personalized Communication ( t s + 1 2 t w ) mp ( p 1 ) 3.5.2. Cut
Pražnikar, Jure [Institute Jožef Stefan, Jamova 39, 1000 Ljubljana (Slovenia); University of Primorska, (Slovenia); Turk, Dušan, E-mail: dusan.turk@ijs.si [Institute Jožef Stefan, Jamova 39, 1000 Ljubljana (Slovenia); Center of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, (Slovenia)
2014-12-01T23:59:59.000Z
The maximum-likelihood free-kick target, which calculates model error estimates from the work set and a randomly displaced model, proved superior in the accuracy and consistency of refinement of crystal structures compared with the maximum-likelihood cross-validation target, which calculates error estimates from the test set and the unperturbed model. The refinement of a molecular model is a computational procedure by which the atomic model is fitted to the diffraction data. The commonly used target in the refinement of macromolecular structures is the maximum-likelihood (ML) function, which relies on the assessment of model errors. The current ML functions rely on cross-validation. They utilize phase-error estimates that are calculated from a small fraction of diffraction data, called the test set, that are not used to fit the model. An approach has been developed that uses the work set to calculate the phase-error estimates in the ML refinement from simulating the model errors via the random displacement of atomic coordinates. It is called ML free-kick refinement as it uses the ML formulation of the target function and is based on the idea of freeing the model from the model bias imposed by the chemical energy restraints used in refinement. This approach for the calculation of error estimates is superior to the cross-validation approach: it reduces the phase error and increases the accuracy of molecular models, is more robust, provides clearer maps and may use a smaller portion of data for the test set for the calculation of R{sub free} or may leave it out completely.
Studies on design of a process for organo-refining of coal to obtain super clean coal
Sharma, C.S.; Sharma, D.K. [Indian Inst. of Tech., New Delhi (India). Centre for Energy Studies
1999-08-01T23:59:59.000Z
Organo-refining of coal results in refining the coal to obtain super clean coal and residual coal. Super clean coal may be used to obtain value added chemicals, products, and cleaner fuels from coal. In the present work, studies on the design of a semicontinuous process for organo-refining of one ton of coal have been made. The results are reported. This is only a cursory attempt for the design, and further studies may be required for designing this process for use in the development of a scaled-up process of organo-refining of coal.
Tautges, T. J.; Jain, R.; Mathematics and Computer Science
2010-01-01T23:59:59.000Z
Nuclear reactor cores are constructed as rectangular or hexagonal lattices of assemblies, where each assembly is itself a lattice of fuel, control, and instrumentation pins, surrounded by water or other material that moderates neutron energy and carries away fission heat. We describe a system for generating geometry and mesh for these systems. The method takes advantage of information about repeated structures in both assembly and core lattices to simplify the overall process. The system allows targeted user intervention midway through the process, enabling modification and manipulation of models for meshing or other purposes. Starting from text files describing assemblies and core, the tool can generate geometry and mesh for these models automatically as well. Simple and complex examples of tool operation are given, with the latter demonstrating generation of meshes with 12 million hexahedral elements in less than 30 minutes on a desktop workstation, using about 4 GB of memory. The tool is released as open source software as part of the MeshKit mesh generation library.
A Cut-Cell Approach for 2D Cartesian Meshes that Preserves Orthogonal Grid Sweep Ordering
Jarrell, Joshua J [ORNL] [ORNL; Grove, Robert E [ORNL] [ORNL; Evans, Thomas M [ORNL] [ORNL
2011-01-01T23:59:59.000Z
In this paper, we present a cut-cell methodology for solving the two-dimensional neutral-particle transport equation on an orthogonal Cartesian grid. We allow the rectangular cell to be subdivided into two polygonal subcells. We ensure that this division (or cut) conserves the volumes of the materials in the subcells and we utilize a step-characteristics (SC) slice balance approach (SBA) to calculate the angular fluxes exiting the cell as well as the average scalar fluxes in each subcell. Solving the discrete ordinates transport equation on an arbitrary mesh has historically been difficult to parallelize while maintaining good parallel efficiency. However on Cartesian meshes, the KBA algorithm maintains good parallel efficiency using a direct solve. The ability to preserve this algorithm was a driving factor in the development of our cut-cell method. This method also provides a more accurate depiction of a material interface in a cell, which leads to more accurate solutions downstream of this cell. As a result, fewer spatial cells can be utilized, resulting in reduced memory requirements. We apply this approach in the 2D/3D discrete ordinates neutral-particle transport code Denovo, where we analyze a 2D 3 x 3 lattice of pincells. We show that, for eigenvalue problems, a significant increase in accuracy for a given mesh size is gained by utilizing the cut-cell, SC equations instead of the standard homogenized-cell, SC equations.
,"Motor Gasoline Sales to End Users, Total Refiner Sales Volumes"
U.S. Energy Information Administration (EIA) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghurajiConventional Gasoline Sales to End Users, Total Refiner Sales Volumes"forUsers, Total Refiner
,"U.S. Conventional Gasoline Refiner Sales Volumes"
U.S. Energy Information Administration (EIA) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghurajiConventional Gasoline Sales to End Users, Total Refiner SalesConventional Gasoline Refiner Sales
,"U.S. Conventional, Average Refiner Gasoline Prices"
U.S. Energy Information Administration (EIA) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere IRaghurajiConventional Gasoline Sales to End Users, Total Refiner SalesConventional Gasoline Refiner
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProducts (VAP) VAP7-0973 1 IntroductionActinide ChemistryActivitiesAdapting to
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProducts (VAP) VAP7-0973 1 IntroductionActinide ChemistryActivitiesAdapting
BRIDGING NAVIGATION, SEARCH AND ADAPTATION. Adaptive Hypermedia Models Evolution
De Bra, Paul
Corpus, Dexter Model, AHAM, GAF. Abstract: Adaptive Hypermedia Systems (AHS) have long been concentrating The most referenced (but certainly not only) Adaptive Hypermedia (AH) model dates back to 1999. Since AHAM/Hypermedia modelling from Dexter Model through AHAM to the proposed GAF model, out- line advantages of each framework
Alston, T. G.; Humphrey, J. L.
1981-01-01T23:59:59.000Z
Argonne National Laboratory has started a program to identify future RD&D projects that (i) promise cost-effective savings of scarce fuels in the chemical and petroleum refining industries, (ii) are not likely to be pursued by industry alone...
Broader source: Energy.gov [DOE]
The U.S. Department of Energy developed this statement to assess the potential environmental, economic and social impacts associated with the construction and short-term operation of a 6,000-tons-per-stream-day-capacity facility that will demonstrate the technical operability, economic viability, and environmental acceptability of the solvent refined coal process at Fort Martin, West Virginia.
Table 7. U.S. Refiner Motor Gasoline Volumes by Grade and Sales...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
35.2 213.6 9.5 9.8 12.9 16.6 NA 29.5 See footnotes at end of table. 7. U.S. Refiner Motor Gasoline Volumes by Grade and Sales Type 14 Energy Information Administration ...
Table A1. Refiner/Reseller Motor Gasoline Prices by Grade, PAD...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
71.6 92.3 78.2 101.8 83.6 87.5 74.7 See footnotes at end of table. A1. RefinerReseller Motor Gasoline Prices by Grade, PAD District, and State, 1984-Present 452 Energy Information...
Table 6. U.S. Refiner Motor Gasoline Prices by Grade and Sales...
U.S. Energy Information Administration (EIA) Indexed Site
62.2 68.5 90.1 89.6 82.4 70.9 NA 75.9 See footnotes at end of table. 6. U.S. Refiner Motor Gasoline Prices by Grade and Sales Type 12 Energy Information Administration ...
Table 11. U.S. Refiner Oxygenated Motor Gasoline Volumes by...
U.S. Energy Information Administration (EIA) Indexed Site
- 4.9 0.4 0.4 0.3 0.4 - 0.7 See footnotes at end of table. 11. U.S. Refiner Oxygenated Motor Gasoline Volumes by Grade and Sales Type 22 Energy Information Administration ...
Table 6. U.S. Refiner Motor Gasoline Prices by Grade and Sales...
U.S. Energy Information Administration (EIA) Indexed Site
61.5 67.3 89.8 89.5 82.2 69.4 71.1 74.9 See footnotes at end of table. 6. U.S. Refiner Motor Gasoline Prices by Grade and Sales Type 12 Energy Information Administration ...
Table 7. U.S. Refiner Motor Gasoline Volumes by Grade and Sales...
Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]
33.9 215.8 9.7 10.0 12.1 16.3 0.0 28.4 See footnotes at end of table. 7. U.S. Refiner Motor Gasoline Volumes by Grade and Sales Type 14 Energy Information Administration ...
Table 11. U.S. Refiner Oxygenated Motor Gasoline Volumes by...
U.S. Energy Information Administration (EIA) Indexed Site
W 5.6 0.5 0.5 0.5 0.4 - 0.9 See footnotes at end of table. 11. U.S. Refiner Oxygenated Motor Gasoline Volumes by Grade and Sales Type 22 Energy Information Administration ...
The Nekrasov-Okounkov hook length formula: refinement, elementary proof, extension and applications
Paris-Sud XI, Université de
2008/05/09 The Nekrasov-Okounkov hook length formula: refinement, elementary proof, extension and applications Guo-Niu HAN ABSTRACT. -- The paper is devoted to the derivation of the expan- sion formula function for t-cores. Several applications are derived, including the "marked hook formula". 1
Tools for macromolecular model building and refinement into electron cryo-microscopy reconstructions
Brown, Alan; Long, Fei; Nicholls, Robert A.; Toots, Jaan; Emsley, Paul; Murshudov, Garib, E-mail: garib@mrc-lmb.cam.ac.uk [MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH (United Kingdom)
2015-01-01T23:59:59.000Z
A description is given of new tools to facilitate model building and refinement into electron cryo-microscopy reconstructions. The recent rapid development of single-particle electron cryo-microscopy (cryo-EM) now allows structures to be solved by this method at resolutions close to 3 Ĺ. Here, a number of tools to facilitate the interpretation of EM reconstructions with stereochemically reasonable all-atom models are described. The BALBES database has been repurposed as a tool for identifying protein folds from density maps. Modifications to Coot, including new Jiggle Fit and morphing tools and improved handling of nucleic acids, enhance its functionality for interpreting EM maps. REFMAC has been modified for optimal fitting of atomic models into EM maps. As external structural information can enhance the reliability of the derived atomic models, stabilize refinement and reduce overfitting, ProSMART has been extended to generate interatomic distance restraints from nucleic acid reference structures, and a new tool, LIBG, has been developed to generate nucleic acid base-pair and parallel-plane restraints. Furthermore, restraint generation has been integrated with visualization and editing in Coot, and these restraints have been applied to both real-space refinement in Coot and reciprocal-space refinement in REFMAC.
Grain refinement and texture development of cast bi90sb10 alloy via severe plastic deformation
Im, Jae-taek
2009-05-15T23:59:59.000Z
The purpose of this work was to study learn about grain refinement mechanisms and texture development in cast n-type Bi90Sb10 alloy caused by severe plastic deformation. The practical objective is to produce a fine grained and textured...
Proceedings of the conference on electron beam melting and refining - state of the art 1996
Bakish, R. [ed.
1996-12-31T23:59:59.000Z
This conference proceedings summarizes state-of-the-art work in the field of electron-beam melting and refining, as presented at the 1996 conference. Papers are grouped as follows: invited papers; tutorial papers; electron beam melting related fundamentals; electron beam evaporation papers; and miscellaneous papers. Separate abstracts have been submitted to the energy database for some contributions to this proceedings.
REFINING AND MAINTAINING THE OPTIMAL PERFORMANCE OF THE CEBAF SRF SYSTEMS *
REFINING AND MAINTAINING THE OPTIMAL PERFORMANCE OF THE CEBAF SRF SYSTEMS * C. Reece, J. Benesch CEBAF at Jefferson Lab is striving to achieve its maximum reliability at the maximum deliverable energy beam time when CEBAF is run near its maximum energy. Operation at increased rf power levels has
Rocky Mountain area petroleum product availability with reduced PADD IV refining capacity
Hadder, G.R.; Chin, S.M.
1994-02-01T23:59:59.000Z
Studies of Rocky Mountain area petroleum product availability with reduced refining capacity in Petroleum Administration for Defense IV (PADD IV, part of the Rocky Mountain area) have been performed with the Oak Ridge National Laboratory Refinery Yield Model, a linear program which has been updated to blend gasolines to satisfy constraints on emissions of nitrogen oxides and winter toxic air pollutants. The studies do not predict refinery closures in PADD IV. Rather, the reduced refining capacities provide an analytical framework for probing the flexibility of petroleum refining and distribution for winter demand conditions in the year 2000. Industry analysts have estimated that, for worst case scenarios, 20 to 35 percent of PADD IV refining capacity could be shut-down as a result of clean air and energy tax legislation. Given these industry projections, the study scenarios provide the following conclusions: The Rocky Mountain area petroleum system would have the capability to satisfy winter product demand with PADD IV refinery capacity shut-downs in the middle of the range of industry projections, but not in the high end of the range of projections. PADD IV crude oil production can be maintained by re-routing crude released from PADD IV refinery demands to satisfy increased crude oil demands in PADDs II (Midwest), III (Gulf Coast), and Washington. Clean Air Act product quality regulations generally do not increase the difficulty of satisfying emissions reduction constraints in the scenarios.