Mesoscale Modeling Spring Semester 2014
is to present the development of the basic equations used in mesoscale models, as well as the various methods Integrity: All students are subject to the policies regarding academic integrity found in Section 1://www.conflictresolution.colostate.edu/conduct-code). Other information on academic integrity can be found on the Learning@CSU website (http://learning.colostate.edu/integrity
Rotational and divergent kinetic energy in the mesoscale model ALADIN
Zagar, Nedjeljka
energy, divergent energy, ALADIN, limited-area modelling 1. Introduction Horizontal divergenceRotational and divergent kinetic energy in the mesoscale model ALADIN By V. BLAZ ICA1 *, N. Z AGAR1 received 7 June 2012; in final form 7 March 2013) ABSTRACT Kinetic energy spectra from the mesoscale
Wind resource assessment with a mesoscale non-hydrostatic model
Boyer, Edmond
Wind resource assessment with a mesoscale non- hydrostatic model Vincent Guénard, Center for Energy is developed for assessing the wind resource and its uncertainty. The work focuses on an existing wind farm mast measurements. The wind speed and turbulence fields are discussed. It is shown that the k
MESOSCALE MODELLING OF WIND ENERGY OVER NON-HOMOGENEOUS TERRAIN
Pielke, Roger A.
MESOSCALE MODELLING OF WIND ENERGY OVER NON-HOMOGENEOUS TERRAIN (ReviewArticle) Y. MAHRER.1. OBSERVATIONALAPPROACHES Evaluations of wind energy based on wind observations (usually surface winds) at well, the resolution of the wind energy pattern throughout an extended area by this methodology requires a large number
WIND ATLAS FOR EGYPT: MEASUREMENTS, MICRO-AND MESOSCALE MODELLING
sets for evaluating the potential wind power output from large electricity-producing wind turbine and accurate wind atlas data sets for evaluating the potential wind power output from large electricityWIND ATLAS FOR EGYPT: MEASUREMENTS, MICRO- AND MESOSCALE MODELLING Niels G. Mortensen1 , Jens
STATISTICAL MECHANICS MODELING OF MESOSCALE DEFORMATION IN METALS
Anter El-Azab
2013-04-08T23:59:59.000Z
The research under this project focused on a theoretical and computational modeling of dislocation dynamics of mesoscale deformation of metal single crystals. Specifically, the work aimed to implement a continuum statistical theory of dislocations to understand strain hardening and cell structure formation under monotonic loading. These aspects of crystal deformation are manifestations of the evolution of the underlying dislocation system under mechanical loading. The project had three research tasks: 1) Investigating the statistical characteristics of dislocation systems in deformed crystals. 2) Formulating kinetic equations of dislocations and coupling these kinetics equations and crystal mechanics. 3) Computational solution of coupled crystal mechanics and dislocation kinetics. Comparison of dislocation dynamics predictions with experimental results in the area of statistical properties of dislocations and their field was also a part of the proposed effort. In the first research task, the dislocation dynamics simulation method was used to investigate the spatial, orientation, velocity, and temporal statistics of dynamical dislocation systems, and on the use of the results from this investigation to complete the kinetic description of dislocations. The second task focused on completing the formulation of a kinetic theory of dislocations that respects the discrete nature of crystallographic slip and the physics of dislocation motion and dislocation interaction in the crystal. Part of this effort also targeted the theoretical basis for establishing the connection between discrete and continuum representation of dislocations and the analysis of discrete dislocation simulation results within the continuum framework. This part of the research enables the enrichment of the kinetic description with information representing the discrete dislocation systems behavior. The third task focused on the development of physics-inspired numerical methods of solution of the coupled dislocation kinetics and crystal mechanics framework. To a large extent, this task has also been successfully started. We have developed a custom finite-element approach with mesh points being a subset of the underlying crystal structure. When used to predict the evolution of the dislocation system, the planar motion of dislocations is naturally captured for all slip systems, thus minimizing numerical errors and providing simple ways to investigate cross slip and dislocation reactions. Preliminary results in this direction show that we are closer than ever in building a predictive framework for dislocation dynamics and mesoscale plasticity based on the first principles of dislocation dynamics. The rest of the report gives and overview of the research performed under this project and highlights the key results and open questions left for future investigations.
Mesoscale Modeling of LX-17 Under Isentropic Compression
Springer, H K; Willey, T M; Friedman, G; Fried, L E; Vandersall, K S; Baer, M R
2010-03-06T23:59:59.000Z
Mesoscale simulations of LX-17 incorporating different equilibrium mixture models were used to investigate the unreacted equation-of-state (UEOS) of TATB. Candidate TATB UEOS were calculated using the equilibrium mixture models and benchmarked with mesoscale simulations of isentropic compression experiments (ICE). X-ray computed tomography (XRCT) data provided the basis for initializing the simulations with realistic microstructural details. Three equilibrium mixture models were used in this study. The single constituent with conservation equations (SCCE) model was based on a mass-fraction weighted specific volume and the conservation of mass, momentum, and energy. The single constituent equation-of-state (SCEOS) model was based on a mass-fraction weighted specific volume and the equation-of-state of the constituents. The kinetic energy averaging (KEA) model was based on a mass-fraction weighted particle velocity mixture rule and the conservation equations. The SCEOS model yielded the stiffest TATB EOS (0.121{micro} + 0.4958{micro}{sup 2} + 2.0473{micro}{sup 3}) and, when incorporated in mesoscale simulations of the ICE, demonstrated the best agreement with VISAR velocity data for both specimen thicknesses. The SCCE model yielded a relatively more compliant EOS (0.1999{micro}-0.6967{micro}{sup 2} + 4.9546{micro}{sup 3}) and the KEA model yielded the most compliant EOS (0.1999{micro}-0.6967{micro}{sup 2}+4.9546{micro}{sup 3}) of all the equilibrium mixture models. Mesoscale simulations with the lower density TATB adiabatic EOS data demonstrated the least agreement with VISAR velocity data.
MESOSCALE AVERAGING OF NUCLEATION AND GROWTH MODELS
Burger, Martin
(cf. e.g. [49]), semiconductor crystal growth (cf. [37]), biomineralization (cf. e.g. [48]), DNA (cf. e.g. [2, 4, 10, 26, 28, 32]). The aim of this paper is to bridge between these two type of models
Meso-Scale Model for Simulations of Concrete Subjected to Cryogenic Temperatures
Masad, Noor Ahmad
2013-07-17T23:59:59.000Z
software ABAQUS. In this model, concrete is considered as a 3- phase composite material in a meso-scale structure: mortar matrix, aggregate, and interfacial transmission zone (ITZ). The Concrete Damage Plasticity model in ABAQUS is used to represent...
Mesoscale Modeling During Mixed-Phase Arctic Cloud Experiment
Avramov, A.; Harringston, J.Y.; Verlinde, J.
2005-03-18T23:59:59.000Z
Mixed-phase arctic stratus clouds are the predominant cloud type in the Arctic (Curry et al. 2000) and through various feedback mechanisms exert a strong influence on the Arctic climate. Perhaps one of the most intriguing of their features is that they tend to have liquid tops that precipitate ice. Despite the fact that this situation is colloidally unstable, these cloud systems are quite long lived - from a few days to over a couple of weeks. It has been hypothesized that mixed-phase clouds are maintained through a balance between liquid water condensation resulting from the cloud-top radiative cooling and ice removal by precipitation (Pinto 1998; Harrington et al. 1999). In their modeling study Harrington et al. (1999) found that the maintenance of this balance depends strongly on the ambient concentration of ice forming nucleus (IFN). In a follow-up study, Jiang et al. (2002), using only 30% of IFN concentration predicted by Meyers et al. (1992) IFN parameterization were able to obtain results similar to the observations reported by Pinto (1998). The IFN concentration measurements collected during the Mixed-Phase Arctic Cloud Experiment (M-PACE), conducted in October 2004 over the North Slope of Alaska and the Beaufort Sea (Verlinde et al. 2005), also showed much lower values then those predicted (Prenne, pers. comm.) by currently accepted ice nucleation parameterizations (e.g. Meyers et al. 1992). The goal of this study is to use the extensive IFN data taken during M-PACE to examine what effects low IFN concentrations have on mesoscale cloud structure and coastal dynamics.
Meso-scale eects of tropical deforestation in Amazonia: preparatory LBA modelling studies
Paris-Sud XI, Université de
Meso-scale eects of tropical deforestation in Amazonia: preparatory LBA modelling studies A. J forest is good, above deforested areas (pasture) poor. The models' underestimate of the temperature Modelling studies with general circulation models have shown that large-scale deforestation of the Amazon
Niyogi, Dev
Development and Evaluation of a Coupled Photosynthesis-Based Gas Exchange Evapotranspiration Model (GEM) for Mesoscale Weather Forecasting Applications DEV NIYOGI Department of Agronomy, and Department form 13 May 2008) ABSTRACT Current land surface schemes used for mesoscale weather forecast models use
Spatial-temporal mesoscale modelling of rainfall intensity using gage and radar data
Reich, Brian J.
Spatial-temporal mesoscale modelling of rainfall intensity using gage and radar data Montserrat fields. Doppler radar data offer better spatial and temporal coverage, but Doppler radar measures values. We use spatial logistic regression to model the probability of rain for both sources of data
Mesoscale modelling for an offshore wind farm Jake Badger*, Rebecca Barthelmie, Sten Frandsen for an offshore wind farm in a coastal location. Spatial gradients and vertical profiles between 25 m and 70 m offshore wind farms tend to be placed within the coastal zone, the region within around 50km from
Draxl, C.; Churchfield, M.; Mirocha, J.; Lee, S.; Lundquist, J.; Michalakes, J.; Moriarty, P.; Purkayastha, A.; Sprague, M.; Vanderwende, B.
2014-06-01T23:59:59.000Z
Wind plant aerodynamics are influenced by a combination of microscale and mesoscale phenomena. Incorporating mesoscale atmospheric forcing (e.g., diurnal cycles and frontal passages) into wind plant simulations can lead to a more accurate representation of microscale flows, aerodynamics, and wind turbine/plant performance. Our goal is to couple a numerical weather prediction model that can represent mesoscale flow [specifically the Weather Research and Forecasting model] with a microscale LES model (OpenFOAM) that can predict microscale turbulence and wake losses.
Meng, Zhiyong
degraded). As in Part I, where the perfect model assumption was utilized, most analysis error reduction of significant model errors due to physical parameterizations by assimilating synthetic sounding and surfaceTests of an Ensemble Kalman Filter for Mesoscale and Regional-Scale Data Assimilation. Part II
Cloud shading retrieval and assimilation in a satellite-model coupled mesoscale analysis system
Lipton, A.E. (Phillips Lab., Hanscom AFB, MA (United States))
1993-11-01T23:59:59.000Z
A retrieval-assimilation method has been developed as a quantitative means to exploit the information in satellite imagery regarding shading of the ground by clouds, as applied to mesoscale weather analysis. Cloud radiative parameters are retrieved from satellite visible image data and used, along with parameters computed by a numerical model, to control the model's computation of downward radiative fluxes at the ground. These fluxes influence the analysis of ground surface temperatures under clouds. The method is part of a satellite-model coupled four-dimensional analysis system that merges information from visible image data in cloudy areas with infrared sounder data in clear areas, where retrievals of surface temperatures and water vapor concentrations are assimilated. The substantial impact of shading on boundary-layer development and mesoscale circulations was demonstrated in simulations, and the value of assimilating shading retrievals was demonstrated with a case study and with a simulated analysis that included the effects of several potential sources of error. The case study was performed in the northwestern Texas area, where convective cloud development was influenced by the shading effects of a persistent region of stratiform cloud cover. Analyses that included shading retrieval assimilation had consistently smaller shelter-height temperature errors than analyses without shading retrievals. When clear-area surface temperature retrievals from sounder data were analyzed along with cloudy-area shading retrievals, the contrast in heating between the shaded and clear parts of the domain led to large variations in analyzed boundary-layer depths and had a modest impact on analyzed wind flow. The analyzed locations of upward vertical motion corresponded roughly to areas of convective cloud development observed in satellite imagery. 29 refs., 17 figs., 2 tabs.
Finite Element Modeling of Drilling Using DEFORM
Gardner, Joel D.; Dornfeld, David
2006-01-01T23:59:59.000Z
Vijayaraghavan, A. (2005), Drilling of Fiber- ReinforcedFINITE ELEMENT MODELING OF DRILLING USING DEFORM J. Gardner,of Comprehensive Drilling Simulation Tool ABSTRACT DEFORM-
Ismael Hernndez-Carrasco; Vincent Rossi; Emilio Hernndez-Garca; Veronique Garon; Cristbal Lpez
2013-11-05T23:59:59.000Z
Recent studies, both based on remote sensed data and coupled models, showed a reduction of biological productivity due to vigorous horizontal stirring in upwelling areas. In order to better understand this phenomenon, we consider a system of oceanic flow from the Benguela area coupled with a simple biogeochemical model of Nutrient-Phyto-Zooplankton (NPZ) type. For the flow three different surface velocity fields are considered: one derived from satellite altimetry data, and the other two from a regional numerical model at two different spatial resolutions. We compute horizontal particle dispersion in terms of Lyapunov Exponents, and analyzed their correlations with phytoplankton concentrations. Our modelling approach confirms that in the south Benguela there is a reduction of biological activity when stirring is increased. Two-dimensional offshore advection and latitudinal difference in Primary Production, also mediated by the flow, seem to be the dominant processes involved. We estimate that mesoscale processes are responsible for 30 to 50% of the offshore fluxes of biological tracers. In the northern area, other factors not taken into account in our simulation are influencing the ecosystem. We suggest explanations for these results in the context of studies performed in other eastern boundary upwelling areas.
Processing of cloud condensation nuclei by collision-coalescence in a mesoscale model
Mechem, David B.; Robinson, Paul C.; Kogan, Yefim L.
2006-09-26T23:59:59.000Z
The Naval Research Laboratory's Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) is employed to explore the relative importance of source, sink, and transport processes in producing an accurate forecast of the ...
Meso-Scale Modeling of Spall in a Heterogeneous Two-Phase Material
Springer, H K
2008-06-26T23:59:59.000Z
The influence of the heterogeneous second-phase particle structure and applied loading conditions on the ductile spall response of a model two-phase material was investigated. Quantitative metallography, three-dimensional (3D) meso-scale simulations (MSS), and small-scale spall experiments provided the foundation for this study. Nodular ductile iron (NDI) was selected as the model two-phase material for this study because it contains a large and readily identifiable second- phase particle population. Second-phase particles serve as the primary void nucleation sites in NDI and are, therefore, central to its ductile spall response. A mathematical model was developed for the NDI second-phase volume fraction that accounted for the non-uniform particle size and spacing distributions within the framework of a length-scale dependent Gaussian probability distribution function (PDF). This model was based on novel multiscale sampling measurements. A methodology was also developed for the computer generation of representative particle structures based on their mathematical description, enabling 3D MSS. MSS were used to investigate the effects of second-phase particle volume fraction and particle size, loading conditions, and physical domain size of simulation on the ductile spall response of a model two-phase material. MSS results reinforce existing model predictions, where the spall strength metric (SSM) logarithmically decreases with increasing particle volume fraction. While SSM predictions are nearly independent of applied load conditions at lower loading rates, which is consistent with previous studies, loading dependencies are observed at higher loading rates. There is also a logarithmic decrease in SSM for increasing (initial) void size, as well. A model was developed to account for the effects of loading rate, particle size, matrix sound-speed, and, in the NDI-specific case, the probabilistic particle volume fraction model. Small-scale spall experiments were designed and executed for the purpose of validating closely-coupled 3D MSS. While the spall strength is nearly independent of specimen thickness, the fragment morphology varies widely. Detailed MSS demonstrate that the interactions between the tensile release waves are altered by specimen thickness and that these interactions are primarily responsible for fragment formation. MSS also provided insights on the regional amplification of damage, which enables the development of predictive void evolution models.
Jochum, Markus
-term in situ measurements. Given the shallow mixed layer, this additional surface heat flux warms the cold of the ocean. The observed relationship between the near-surface winds and mesoscale SSTs generate Ekman pump- ing velocities at the scale of the cold filaments, whose magnitude is the order of 1 m/day in both
Churchfield, M. J.; Michalakes, J.; Vanderwende, B.; Lee, S.; Sprague, M. A.; Lundquist, J. K.; Moriarty, P. J.
2013-10-01T23:59:59.000Z
Wind plant aerodynamics are directly affected by the microscale weather, which is directly influenced by the mesoscale weather. Microscale weather refers to processes that occur within the atmospheric boundary layer with the largest scales being a few hundred meters to a few kilometers depending on the atmospheric stability of the boundary layer. Mesoscale weather refers to large weather patterns, such as weather fronts, with the largest scales being hundreds of kilometers wide. Sometimes microscale simulations that capture mesoscale-driven variations (changes in wind speed and direction over time or across the spatial extent of a wind plant) are important in wind plant analysis. In this paper, we present our preliminary work in coupling a mesoscale weather model with a microscale atmospheric large-eddy simulation model. The coupling is one-way beginning with the weather model and ending with a computational fluid dynamics solver using the weather model in coarse large-eddy simulation mode as an intermediary. We simulate one hour of daytime moderately convective microscale development driven by the mesoscale data, which are applied as initial and boundary conditions to the microscale domain, at a site in Iowa. We analyze the time and distance necessary for the smallest resolvable microscales to develop.
Development and validation of a vertically two-dimensional mesoscale numerical model
Walters, Michael Kent
2012-06-07T23:59:59.000Z
because the model is dry. The equations are as follows: dv " ? 1 1 d dv f k X V ? ? Vp ? g Vz + ? ~ ? (pK ? ), (2) dt P pH ds m ds pgH do dn d o + 'it ~ pV + ? (ns) + p V ~ VH = 0 dt ds P H (4) dT . H Q sg ? + d t C p C p pRT The symbols... of the model. The remaining variables have been previously defined. 15 The finite difference equations are as follows: ~ H (o V (i, k) = H(i+1) * ( p(i+1, k) + p(i, k) ) * u(i+1, k) ? H(i) * ( p(i, k) + p (i-l, k) ) * u(i, k) / ( 2 a DX ) = DV(i k) (I...
Application of Finite Mixture Models for Vehicle Crash Data Analysis
Park, Byung Jung
2010-07-14T23:59:59.000Z
heterogeneity through the use of finite mixture regression models. A Finite mixture of Poisson or NB regression models is especially useful when the count data were generated from a heterogeneous population. To evaluate these models, Poisson and NB mixture...
Coupling the High Complexity Land Surface Model ACASA to the Mesoscale Model WRF
Xu, L.
In this study, the Weather Research and Forecasting Model (WRF) is coupled with the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA), a high complexity land surface model. Although WRF is a state-of-the-art regional ...
Berri, G.J.; Nunez, M.N. (Universidad de Buenos Aires (Argentina) Pabellon II Ciudad Universitaria, Buenos Aires (Argentina))
1993-05-01T23:59:59.000Z
A hydrostatic and incompressible mesoscale model with transformed horizontal coordinates is presented. The model is applied to study the sea-land-breeze circulation over Rio de La Plata. One of the new coordinates is shoreline-following and the other one is locally quasi-perpendicular to the first one. The original set of equations in the Cartesian coordinates is rewritten in the curvilinear coordinates. This transformation is useful provided that the curvilinear coordinates are close to being orthogonal. The horizontal domain covers 250 km [times] 250 km, and the vertical domain is 2 km deep. To predict the sea-land-breeze circulation the model is integrated over 12 h. The forcing of the model is a cyclic perturbation of the surface temperature. The changes in the wind direction during the day are in good agreement with the observations from six weather stations in the region. The same program code is applied to uniform domains of different resolutions in order to test the coordinate transformation. Results show that the predictions based upon the variable-resolution version resemble ones obtained using high uniform resolution but consume only one-fourth the computer time needed by the latter. Comparison of the vertical velocity patterns predicted by the model to the cumulus clouds distribution observed from satellite images show a very good agreement too. The authors believe that all these results justify the use of the coordinate transformation in this type of model, although further verifications are needed in order to draw more definitive conclusions. 28 refs., 11 figs.
Lee, In Young
1993-09-01T23:59:59.000Z
The distribution of atmospheric pollutants is governed by dynamic processes that create the general conditions for transport and mixing, by microphysical processes that control the evolution of aerosol and cloud particles, and by chemical processes that transform chemical species and form aerosols. Pollutants emitted into the air can undergo homogeneous gas reactions to create a suitable environment for the production by heterogeneous nucleation of embryos composed of a few molecules. The physicochemical properties of preexisting aerosols interact with newly produced embryos to evolve by heteromolecular diffusion and coagulation. Hygroscopic particles wig serve as effective cloud condensation nuclei (CCN), while hydrophobic particles will serve as effective ice-forming nuclei. Clouds form initially by condensation of water vapor on CCN and evolve in a vapor-liquid-solid system by deposition, sublimation, freezing, melting, coagulation, and breakup. Gases and aerosols that enter the clouds undergo aqueous chemical processes and may acidity hydrometer particles. Calculations for solar and longwave radiation fluxes depend on how the respective spectra are modified by absorbers such as H{sub 2}O, CO{sub 2}, O{sub 3}, CH{sub 4}, N{sub 2}O, chlorofruorocarbons, and aerosols. However, the flux calculations are more complicated for cloudy skies, because the cloud optical properties are not well defined. In this paper, key processes such as tropospheric chemistry, cloud microphysics parameterizations, and radiation schemes are reviewed in terms of physicochemical processes occurring, and recommendations are made for the development of advanced modules applicable to mesoscale models.
Self-Assembly of Mesoscale Isomers: The Role of Pathways and Degrees of Freedom
Menon, Govind
Self-Assembly of Mesoscale Isomers: The Role of Pathways and Degrees of Freedom Shivendra Pandey1 geometric path sampling and a mesoscale experimental model to investigate the self-assembly of a model. Citation: Pandey S, Johnson D, Kaplan R, Klobusicky J, Menon G, et al. (2014) Self-Assembly of Mesoscale
Silicon Micromachined Dimensional Calibration Artifact for Mesoscale...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Micromachined Dimensional Calibration Artifact for Mesoscale Measurement Machines 1 Silicon Micromachined Dimensional Calibration Artifact for Mesoscale Measurement Machines 2...
Modeling a bender element test using Abaqus Finite Element Program
Johnson, Sean (Sean Michael)
2011-01-01T23:59:59.000Z
Finite Element Methods hold promise for modeling the behavior of an unsaturated soil specimen subjected to bender element agitation. The immediate objective of this research project is to reproduce a bender element test ...
A frequency domain finite element model for tidal circulation
Westerink, Joannes J.
1985-01-01T23:59:59.000Z
A highly efficient finite element model has been developed for the numerical prediction of depth average circulation within small scale embayments which are often characterized by irregular boundaries and bottom topography.
Impact of Agricultural Practice on Regional Climate in a CoupledLand Surface Mesoscale Model
Cooley, H.S.; Riley, W.J.; Torn, M.S.; He, Y.
2004-07-01T23:59:59.000Z
The land surface has been shown to form strong feedbacks with climate due to linkages between atmospheric conditions and terrestrial ecosystem exchanges of energy, momentum, water, and trace gases. Although often ignored in modeling studies, land management itself may form significant feedbacks. Because crops are harvested earlier under drier conditions, regional air temperature, precipitation, and soil moisture, for example, affect harvest timing, particularly of rain-fed crops. This removal of vegetation alters the land surface characteristics and may, in turn, affect regional climate. We applied a coupled climate(MM5) and land-surface (LSM1) model to examine the effects of early and late winter wheat harvest on regional climate in the Department of Energy Atmospheric Radiation Measurement (ARM) Climate Research Facility in the Southern Great Plains, where winter wheat accounts for 20 percent of the land area. Within the winter wheat region, simulated 2 m air temperature was 1.3 C warmer in the Early Harvest scenario at mid-day averaged over the two weeks following harvest. Soils in the harvested area were drier and warmer in the top 10 cm and wetter in the 10-20 cm layer. Midday soils were 2.5 C warmer in the harvested area at mid-day averaged over the two weeks following harvest. Harvest also dramatically altered latent and sensible heat fluxes. Although differences between scenarios diminished once both scenarios were harvested, the short-term impacts of land management on climate were comparable to those from land cover change demonstrated in other studies.
McArthur, Karl Edward
1996-01-01T23:59:59.000Z
, and constituent fluxes. The finite difference scheme in SW=D is based on a spatial discretization of the water body as a grid of equal sized, square cers. The model includes the effects of wetting and drying, wind, inflows and return flows, flow barriers...
Compositional modeling of threephase flow with gravity using higherorder finite element methods
Firoozabadi, Abbas
Compositional modeling of threephase flow with gravity using higherorder finite element methods using higherorder finite element methods. Gravity poses complications in modeling multiphase processes flow with gravity using higherorder finite element methods, Water Resour. Res., 47, W05511, doi:10
Finite element modeling of syntactic foam.
Hobbs, Michael L.
2004-10-01T23:59:59.000Z
A decomposition model has been developed to predict the response of removable syntactic foam (RSF) exposed to fire-like heat fluxes. RSF consists of glass micro-balloons (GMB) in a cured epoxy polymer matrix. A chemistry model is presented based on the chemical structure of the epoxy polymer, mass transport of polymer fragments to the bulk gas, and vapor-liquid equilibrium. Thermophysical properties were estimated from measurements. A bubble nucleation, growth, and coalescence model was used to describe changes in properties with the extent of reaction. Decomposition of a strand of syntactic foam exposed to high temperatures was simulated.
Houze, Jr., Robert A. [University of Washington Dept. of Atmospheric Sciences
2013-11-13T23:59:59.000Z
We examined cloud radar data in monsoon climates, using cloud radars at Darwin in the Australian monsoon, on a ship in the Bay of Bengal in the South Asian monsoon, and at Niamey in the West African monsoon. We followed on with a more in-depth study of the continental MCSs over West Africa. We investigated whether the West African anvil clouds connected with squall line MCSs passing over the Niamey ARM site could be simulated in a numerical model by comparing the observed anvil clouds to anvil structures generated by the Weather Research and Forecasting (WRF) mesoscale model at high resolution using six different ice-phase microphysical schemes. We carried out further simulations with a cloud-resolving model forced by sounding network budgets over the Niamey region and over the northern Australian region. We have devoted some of the effort of this project to examining how well satellite data can determine the global breadth of the anvil cloud measurements obtained at the ARM ground sites. We next considered whether satellite data could be objectively analyzed to so that their large global measurement sets can be systematically related to the ARM measurements. Further differences were detailed between the land and ocean MCS anvil clouds by examining the interior structure of the anvils with the satellite-detected the CloudSat Cloud Profiling Radar (CPR). The satellite survey of anvil clouds in the Indo-Pacific region was continued to determine the role of MCSs in producing the cloud pattern associated with the MJO.
Mesoscale hybrid calibration artifact
Tran, Hy D. (Albuquerque, NM); Claudet, Andre A. (Albuquerque, NM); Oliver, Andrew D. (Waltham, MA)
2010-09-07T23:59:59.000Z
A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.
Test of modified BCS model at finite temperature
V. Yu. Ponomarev; A. I. Vdovin
2005-08-24T23:59:59.000Z
A recently suggested modified BCS (MBCS) model has been studied at finite temperature. We show that this approach does not allow the existence of the normal (non-superfluid) phase at any finite temperature. Other MBCS predictions such as a negative pairing gap, pairing induced by heating in closed-shell nuclei, and ``superfluid -- super-superfluid'' phase transition are discussed also. The MBCS model is tested by comparing with exact solutions for the picket fence model. Here, severe violation of the internal symmetry of the problem is detected. The MBCS equations are found to be inconsistent. The limit of the MBCS applicability has been determined to be far below the ``superfluid -- normal'' phase transition of the conventional FT-BCS, where the model performs worse than the FT-BCS.
MESOSCALE SIMULATIONS OF POWDER COMPACTION
Lomov, Ilya; Fujino, Don; Antoun, Tarabay; Liu, Benjamin [Lawrence Livermore National Laboratory, P. O. Box 808, Livermore CA 94551 (United States)
2009-12-28T23:59:59.000Z
Mesoscale 3D simulations of shock compaction of metal and ceramic powders have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating a well-characterized shock compaction experiment of a porous ductile metal. Simulation results using the Steinberg material model and handbook values for solid 2024 aluminum showed good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not as well studied as metals, so a simple material model for solid ceramic (tungsten carbide) has been calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powders have been performed and showed good agreement with experimental data. The numerical shock wave profile has same character and thickness as that measured experimentally using VISAR. The numerical results show reshock states above the single-shock Hugoniot line as observed in experiments. We found that for good quantitative agreement with experiments 3D simulations are essential.
Mesoscale Dynamics Spring Semester 2014
ATS 735 Mesoscale Dynamics (3 cr) Spring Semester 2014 Instructor: Richard H. Johnson, Room ATS 305, certain topics in mesoscale dynamics may be emphasized more than others. Although basic concepts lectures on some of the topics. Several books that are relevant to the course are: Cloud Dynamics, 1993 (R
An evaluation of finite element models of stiffened plates subjected to impulsive loading
Pedatzur, Omri
2004-01-01T23:59:59.000Z
Different finite element models are evaluated for two very common structures, a cantilever beam and a stiffened plate, subjected to impulsive loading. For the cantilever beam case, the finite element models are one, two ...
Jackson, Jason R.
1996-01-01T23:59:59.000Z
CONSTITUTIVE MODEL EFFECTS ON FINITE ELEMENT MODELING OF ELASTOMER BEHAVIOR IN RADIAL INTERFERENCE SEAL CONFIGURATIONS A Thesis by JASON R. JACKSON Subnutted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1996 Major Subject: Mechanical Engineering CONSTITUTIVE MODEL EFFECTS ON FINITE ELEMENT MODELING OF ELASTOMER BEHAVIOR IN RADIAL INTERFERENCE SEAL CONFIGURATIONS A Thesis by JASON R. JACKSON...
Energy conserving Anisotropic Anhysteretic Magnetic Modelling for Finite Element Analysis
Jens Krause
2012-12-20T23:59:59.000Z
To model ferromagnetic material in finite element analysis a correct description of the constitutive relationship (BH-law) must be found from measured data. This article proposes to use the energy density function as a centrepiece. Using this function, which turns out to be a convex function of the flux density, guarantees energy conservative modelling. The magnetic field strength can be seen as a derivative with respect to the flux density. Especially for anisotropic materials (from lamination and/or grain orientation) this method has advantages. Strictly speaking this method is only valid for anhysteretic and thermodynamically stable material.
Finite Bisimulation of Reactive Untimed Infinite State Systems Modeled as Automata with Variables
Kumar, Ratnesh
1 Finite Bisimulation of Reactive Untimed Infinite State Systems Modeled as Automata with Variables for reactive untimed infinite state systems called input- output extended finite automaton (I/O-EFA), which of a finite bisimilar abstraction. The results are illustrated through examples that model reactive software
Finite Element Multi-physics Modeling for Ohmic Contact of Microswitches , D. Leray1, 2
Boyer, Edmond
Finite Element Multi-physics Modeling for Ohmic Contact of Microswitches H.Liu1, 2 , D. Leray1, 2-physics modelling of electrical contact is accomplished with the finite element commercial package ANSYSTM . Two behaviour of electrical contact with rough surface included. Keywords: multi-physics, finite element
A Finite Element Model for Simulation of Carbon Dioxide Sequestration
Bao, Jie; Xu, Zhijie; Fang, Yilin
2013-11-02T23:59:59.000Z
We present a hydro-mechanical model, followed by stress, deformation, and shear-slip failure analysis for geological sequestration of carbon dioxide (CO2). The model considers the poroelastic effects by taking into account of the two-way coupling between the geomechanical response and the fluid flow process. Analytical solutions for pressure and deformation fields were derived for a typical geological sequestration scenario in our previous work. A finite element approach is introduced here for numerically solving the hydro-mechanical model with arbitrary boundary conditions. The numerical approach was built on an open-source finite element code Elmer, and results were compared to the analytical solutions. The shear-slip failure analysis was presented based on the numerical results, where the potential failure zone is identified. Information is relevant to the prediction of the maximum sustainable injection rate or pressure. The effects of caprock permeability on the fluid pressure, deformation, stress, and the shear-slip failure zone were also quantitatively studied. It was shown that a larger permeability in caprock and base rock leads to a larger uplift but a smaller shear-slip failure zone.
Surface photovoltage measurements and finite element modeling of SAW devices.
Donnelly, Christine
2012-03-01T23:59:59.000Z
Over the course of a Summer 2011 internship with the MEMS department of Sandia National Laboratories, work was completed on two major projects. The first and main project of the summer involved taking surface photovoltage measurements for silicon samples, and using these measurements to determine surface recombination velocities and minority carrier diffusion lengths of the materials. The SPV method was used to fill gaps in the knowledge of material parameters that had not been determined successfully by other characterization methods. The second project involved creating a 2D finite element model of a surface acoustic wave device. A basic form of the model with the expected impedance response curve was completed, and the model is ready to be further developed for analysis of MEMS photonic resonator devices.
Taylor, G.; Dong, C.; Sun, S.
2010-03-18T23:59:59.000Z
A mathematical model for contaminant species passing through fractured porous media is presented. In the numerical model, we combine two locally conservative methods, i.e. mixed finite element (MFE) and the finite volume methods. Adaptive triangle mesh is used for effective treatment of the fractures. A hybrid MFE method is employed to provide an accurate approximation of velocities field for both the fractures and matrix which are crucial to the convection part of the transport equation. The finite volume method and the standard MFE method are used to approximate the convection and dispersion terms respectively. The model is used to investigate the interaction of adsorption with transport and to extract information on effective adsorption distribution coefficients. Numerical examples in different fractured media illustrate the robustness and efficiency of the proposed numerical model.
Tao, Wei-Kuo; Houze, Robert, A., Jr.; Zeng, Xiping
2013-03-14T23:59:59.000Z
This three-year project, in cooperation with Professor Bob Houze at University of Washington, has been successfully finished as planned. Both ARM (the Atmospheric Radiation Measurement Program) data and cloud-resolving model (CRM) simulations were used to identify the water budgets of clouds observed in two international field campaigns. The research results achieved shed light on several key processes of clouds in climate change (or general circulation models), which are summarized below. 1. Revealed the effect of mineral dust on mesoscale convective systems (MCSs) Two international field campaigns near a desert and a tropical coast provided unique data to drive and evaluate CRM simulations, which are TWP-ICE (the Tropical Warm Pool International Cloud Experiment) and AMMA (the African Monsoon Multidisciplinary Analysis). Studies of the two campaign data were contrasted, revealing that much mineral dust can bring about large MCSs via ice nucleation and clouds. This result was reported as a PI presentation in the 3rd ASR Science Team meeting held in Arlington, Virginia in March 2012. A paper on the studies was published in the Journal of the Atmospheric Sciences (Zeng et al. 2013). 2. Identified the effect of convective downdrafts on ice crystal concentration Using the large-scale forcing data from TWP-ICE, ARM-SGP (the Southern Great Plains) and other field campaigns, Goddard CRM simulations were carried out in comparison with radar and satellite observations. The comparison between model and observations revealed that convective downdrafts could increase ice crystal concentration by up to three or four orders, which is a key to quantitatively represent the indirect effects of ice nuclei, a kind of aerosol, on clouds and radiation in the Tropics. This result was published in the Journal of the Atmospheric Sciences (Zeng et al. 2011) and summarized in the DOE/ASR Research Highlights Summaries (see http://www.arm.gov/science/highlights/RMjY5/view). 3. Used radar observations to evaluate model simulations In cooperation with Profs. Bob Houze at University of Washington and Steven Rutledge at Colorado State University, numerical model results were evaluated with observations from W- and C-band radars and CloudSat/TRMM satellites. These studies exhibited some shortcomings of current numerical models, such as too little of thin anvil clouds, directing the future improvement of cloud microphysics parameterization in CRMs. Two papers of Powell et al (2012) and Zeng et al. (2013), summarizing these studies, were published in the Journal of the Atmospheric Sciences. 4. Analyzed the water budgets of MCSs Using ARM data from TWP-ICE, ARM-SGP and other field campaigns, the Goddard CRM simulations were carried out to analyze the water budgets of clouds from TWP-ICE and AMMA. The simulations generated a set of datasets on clouds and radiation, which are available http://cloud.gsfc.nasa.gov/. The cloud datasets were available for modelers and other researchers aiming to improve the representation of cloud processes in multi-scale modeling frameworks, GCMs and climate models. Special datasets, such as 3D cloud distributions every six minutes for TWP-ICE, were requested and generated for ARM/ASR investigators. Data server records show that 86,206 datasets were downloaded by 120 users between April of 2010 and January of 2012. 5. MMF simulations The Goddard MMF (multi-scale modeling framework) has been improved by coupling with the Goddard Land Information System (LIS) and the Goddard Earth Observing System Model, Version 5 (GOES5). It has also been optimized on NASA HEC supercomputers and can be run over 4000 CPUs. The improved MMF with high horizontal resolution (1 x 1 degree) is currently being applied to cases covering 2005 and 2006. The results show that the spatial distribution pattern of precipitation rate is well simulated by the MMF through comparisons with satellite retrievals from the CMOPRH and GPCP data sets. In addition, the MMF results were compared with three reanalyses (MERRA, ERA-Interim and CFSR). Although the MMF tends
A finite difference model for free surface gravity drainage
Couri, F.R.; Ramey, H.J. Jr.
1993-09-01T23:59:59.000Z
The unconfined gravity flow of liquid with a free surface into a well is a classical well test problem which has not been well understood by either hydrologists or petroleum engineers. Paradigms have led many authors to treat an incompressible flow as compressible flow to justify the delayed yield behavior of a time-drawdown test. A finite-difference model has been developed to simulate the free surface gravity flow of an unconfined single phase, infinitely large reservoir into a well. The model was verified with experimental results in sandbox models in the literature and with classical methods applied to observation wells in the Groundwater literature. The simulator response was also compared with analytical Theis (1935) and Ramey et al. (1989) approaches for wellbore pressure at late producing times. The seepage face in the sandface and the delayed yield behavior were reproduced by the model considering a small liquid compressibility and incompressible porous medium. The potential buildup (recovery) simulated by the model evidenced a different- phenomenon from the drawdown, contrary to statements found in the Groundwater literature. Graphs of buildup potential vs time, buildup seepage face length vs time, and free surface head and sand bottom head radial profiles evidenced that the liquid refills the desaturating cone as a flat moving surface. The late time pseudo radial behavior was only approached after exaggerated long times.
Calibration under uncertainty for finite element models of masonry monuments
Atamturktur, Sezer,; Hemez, Francois,; Unal, Cetin
2010-02-01T23:59:59.000Z
Historical unreinforced masonry buildings often include features such as load bearing unreinforced masonry vaults and their supporting framework of piers, fill, buttresses, and walls. The masonry vaults of such buildings are among the most vulnerable structural components and certainly among the most challenging to analyze. The versatility of finite element (FE) analyses in incorporating various constitutive laws, as well as practically all geometric configurations, has resulted in the widespread use of the FE method for the analysis of complex unreinforced masonry structures over the last three decades. However, an FE model is only as accurate as its input parameters, and there are two fundamental challenges while defining FE model input parameters: (1) material properties and (2) support conditions. The difficulties in defining these two aspects of the FE model arise from the lack of knowledge in the common engineering understanding of masonry behavior. As a result, engineers are unable to define these FE model input parameters with certainty, and, inevitably, uncertainties are introduced to the FE model.
Sensitivity of mesoscale gravity waves to the baroclinicity of jet-front systems
Wang, Shuguang
2006-04-12T23:59:59.000Z
To investigate the generation of mesoscale gravity waves from upper-tropospheric jet-front systems, five different life cycles of baroclinic waves are simulated with a high-resolution mesoscale model (MM5 with 10-km grid spacing). The baroclinicity...
Finite-difference modeling of commercial aircraft using TSAR
Pennock, S.T.; Poggio, A.J.
1994-11-15T23:59:59.000Z
Future aircraft may have systems controlled by fiber optic cables, to reduce susceptibility to electromagnetic interference. However, the digital systems associated with the fiber optic network could still experience upset due to powerful radio stations, radars, and other electromagnetic sources, with potentially serious consequences. We are modeling the electromagnetic behavior of commercial transport aircraft in support of the NASA Fly-by-Light/Power-by-Wire program, using the TSAR finite-difference time-domain code initially developed for the military. By comparing results obtained from TSAR with data taken on a Boeing 757 at the Air Force Phillips Lab., we hope to show that FDTD codes can serve as an important tool in the design and certification of U.S. commercial aircraft, helping American companies to produce safe, reliable air transportation.
Three-dimensional finite difference time domain modeling of the Earth-ionosphere cavity resonances
Pasko, Victor
domain (FDTD) model of Schumann resonances (SR) with a set of classical eigenfrequency and quality factorThree-dimensional finite difference time domain modeling of the Earth-ionosphere cavity resonances-dimensional finite difference time domain modeling of the Earth-ionosphere cavity resonances, Geophys. Res. Lett., 32
Stricker, C. [Swiss Federal Institute of Technology, Zuerich (Switzerland); Fernando, R.L. [Louisiana State Univ., New Orleans, LA (United States); Elston, R.C. [Univ. of Illinois, Urbana, IL (United States)
1995-12-01T23:59:59.000Z
This paper presents an extension of the finite polygenic mixed model of Fernando et al. to linkage analysis. The finite polygenic mixed model, extended for linkage analysis, leads to a likelihood that can be calculated using efficient algorithms developed for oligogenic models. For comparison, linkage analysis of 5 simulated 4021-member pedigrees was performed using the usual mixed model of inheritance, approximated by Hasstedt, and the finite polygenic mixed model extended for linkage analysis presented here. Maximum likelihood estimates of the finite polygenic mixed model could be inferred to be closer to the simulated values in these pedigrees. 31 refs., 2 tabs.
Acoustic Characterization of Mesoscale Objects
Chinn, D; Huber, R; Chambers, D; Cole, G; Balogun, O; Spicer, J; Murray, T
2007-03-13T23:59:59.000Z
This report describes the science and engineering performed to provide state-of-the-art acoustic capabilities for nondestructively characterizing mesoscale (millimeter-sized) objects--allowing micrometer resolution over the objects entire volume. Materials and structures used in mesoscale objects necessitate the use of (1) GHz acoustic frequencies and (2) non-contacting laser generation and detection of acoustic waves. This effort demonstrated that acoustic methods at gigahertz frequencies have the necessary penetration depth and spatial resolution to effectively detect density discontinuities, gaps, and delaminations. A prototype laser-based ultrasonic system was designed and built. The system uses a micro-chip laser for excitation of broadband ultrasonic waves with frequency components reaching 1.0 GHz, and a path-stabilized Michelson interferometer for detection. The proof-of-concept for mesoscale characterization is demonstrated by imaging a micro-fabricated etched pattern in a 70 {micro}m thick silicon wafer.
Radhakrishnan, Balasubramaniam [ORNL; Gorti, Sarma B [ORNL; Stoica, Grigoreta M [ORNL; Muralidharan, Govindarajan [ORNL; Stoica, Alexandru Dan [ORNL; Wang, Xun-Li [ORNL; Specht, Eliot D [ORNL; Kenik, Edward A [ORNL; Muth, Thomas R [ORNL
2012-01-01T23:59:59.000Z
The focus of the present research is to develop an integrated deformation and recrystallization model for magnesium alloys at the microstructural length scale. It is known that in magnesium alloys nucleation of recrystallized grains occurs at various microstructural inhomogeneities such as twins and localized deformation bands. However, there is a need to develop models that can predict the evolution of the grain structure and texture developed during recrystallization and grain growth, especially when the deformation process follows a complicated deformation path such as in asymmetric rolling. The deformation model is based on a crystal plasticity approach implemented at the length scale of the microstructure that includes deformation mechanisms based on dislocation slip and twinning. The recrystallization simulation is based on a Monte Carlo technique that operates on the output of the deformation simulations. The nucleation criterion during recrystallization is based on the local stored energy and the Monte Carlo technique is used to simulate the growth of the nuclei due to local stored energy differences and curvature. The model predictions are compared with experimental data obtained through electron backscatter analysis and neutron diffraction.
Brioude, J.; Kim, S. W.; Angevine, Wayne M.; Frost, G. J.; Lee, S. H.; McKeen, S. A.; Trainer, Michael; Fehsenfeld, Fred C.; Holloway, J. S.; Ryerson, T. B.; Williams, E. J.; Petron, Gabrielle; Fast, Jerome D.
2011-10-31T23:59:59.000Z
The 2000 and 2006 Texas Air Quality Study (TexAQS 2000 and 2006) field campaigns took place in eastern Texas in August-October of 2000 and 2006. Several flights of the National Oceanic and Atmospheric Administration (NOAA) and National Center for Atmospheric Research (NCAR) research aircraft were dedicated to characterizing anthropogenic emissions over Houston. Houston is known for having serious problems with non-attainment of air quality standards. We present a method that uses three models and aircraft observations to assess and improve existing emission inventories using an inverse modeling technique. We used 3-dimensional and 4-dimensional variational (3D-VAR and 4D-VAR) inverse modeling techniques based on a least-squares method to improve the spatial and temporal distribution of CO, NOy (sum of all reactive nitrogen compounds), and SO2 emissions predicted by the 4-km-resolution U.S. Environmental Protection Agency (EPA) National Emission Inventory (NEI) for 2005. Differences between the prior and posterior inventories are discussed in detail. We found that in 2006 the prior daytime emissions in the urban area of Houston have to be reduced by 40% {+-} 12% for CO and 7% {+-} 13% for NOy. Over the Houston Ship Channel, where industrial emissions are predominant, the prior emissions have to be reduced by 41% {+-} 15% for CO and 51% {+-} 9% for NOy. Major ports around Houston have their NOy emissions reduced as well, probably due to uncertainties in near-shore ship emissions in the EPA NEI inventory. Using the measurements from the two field campaigns, we assessed the interannual emission variability between 2000 and 2006. Daytime CO emissions from the Houston urban area have been reduced by 8% {+-} 20%, while the NOy emissions have increased by 20% {+-} 12% from 2000 to 2006. In the Houston Ship Channel, the daytime NOy emissions have increased by 13% {+-} 17%. Our results show qualitative consistencies with known changes in Houston emissions sources.
Review of structure representation and reconstruction on mesoscale and microscale
Li, Dongsheng
2014-05-01T23:59:59.000Z
Structure representation and reconstruction on mesoscale and microscale is critical in material design, advanced manufacturing and multiscale modeling. Microstructure reconstruction has been applied in different areas of materials science and technology, structural materials, energy materials, geology, hydrology, etc. This review summarizes the microstructure descriptors and formulations used to represent and algorithms to reconstruct structures at microscale and mesoscale. In the stochastic methods using correlation function, different optimization approaches have been adapted for objective function minimization. A variety of reconstruction approaches are compared in efficiency and accuracy.
A FINITE ELEMENT MODEL FOR THE TIME-DEPENDENT JOULE HEATING PROBLEM*
Larsson, Stig
.3) 0 system models the electric heating* *ial differential equation describing the electric heating of a conducting body. We prove err* *or A FINITE ELEMENT MODEL FOR THE TIME-DEPENDENT JOULE HEATING PROBLEM
Meso-scale machining capabilities and issues
BENAVIDES,GILBERT L.; ADAMS,DAVID P.; YANG,PIN
2000-05-15T23:59:59.000Z
Meso-scale manufacturing processes are bridging the gap between silicon-based MEMS processes and conventional miniature machining. These processes can fabricate two and three-dimensional parts having micron size features in traditional materials such as stainless steels, rare earth magnets, ceramics, and glass. Meso-scale processes that are currently available include, focused ion beam sputtering, micro-milling, micro-turning, excimer laser ablation, femto-second laser ablation, and micro electro discharge machining. These meso-scale processes employ subtractive machining technologies (i.e., material removal), unlike LIGA, which is an additive meso-scale process. Meso-scale processes have different material capabilities and machining performance specifications. Machining performance specifications of interest include minimum feature size, feature tolerance, feature location accuracy, surface finish, and material removal rate. Sandia National Laboratories is developing meso-scale electro-mechanical components, which require meso-scale parts that move relative to one another. The meso-scale parts fabricated by subtractive meso-scale manufacturing processes have unique tribology issues because of the variety of materials and the surface conditions produced by the different meso-scale manufacturing processes.
The representation of boundary currents in a finite element shallow water model
Dben, Peter D
2015-01-01T23:59:59.000Z
We evaluate the influence of local resolution, eddy viscosity, coastline structure, and boundary conditions on the numerical representation of boundary currents in a finite element shallow-water model. The use of finite element discretization methods offers a higher flexibility compared to finite difference and finite volume methods, that are mainly used in previous publications. This is true for the geometry of the coast lines and for the realization of boundary conditions. For our investigations we simulate steady separation of western boundary currents from idealized and realistic coast lines. The use of grid refinement allows a detailed investigation of boundary separation at reasonable numerical cost.
A mixed finite-element scheme of a semiconductor energy-transport model
Hanke-Bourgeois, Martin
A mixed finite-element scheme of a semiconductor energy-transport model using dual entropy variables Stephan Gadau, Ansgar J¨ungel, and Paola Pietra Abstract. One-dimensional stationary energy employing a mixed-hybrid finite- element method which has the advantage to fulfill current conser- vation
Analysis of a finite element formulation for modelling phase separation
Wells, G N; Garikipati, Krishna
2007-01-01T23:59:59.000Z
equation, which makes its numerical solution particularly challenging. To this end, a finite element formulation has been developed which can solve the Cahn-Hilliard equation in its primal form using C^0 basis functions. Here, analysis of a fully discrete...
Finite Element Modelling and Molecular Dynamic Simulations of Carbon nanotubes/ Polymer Composites
Gaddamanugu, Dhatri
2010-07-14T23:59:59.000Z
Modeling of single-walled carbon nanotubes, multi-walled nanotubes and nanotube reinforced polymer composites using both the Finite Element method and the Molecular Dynamic simulation technique is presented. Nanotubes subjected to mechanical loading...
Lee, Sang Hoon
2012-02-14T23:59:59.000Z
, changing rock permeability. In this work, two- and three-dimensional finite element methods were developed to simulate coupled reservoirs with damage mechanics and stress-dependent permeability. The model considers the influence of fluid flow, temperature...
Reeder, D. Benjamin (Davis Benjamin), 1966-
2002-01-01T23:59:59.000Z
This thesis investigates the complexities of acoustic scattering by finite bodies in general and by fish in particular through the development of an advanced acoustic scattering model and detailed laboratory acoustic ...
TEA - a linear frequency domain finite element model for tidal embayment analysis
Westerink, Joannes J.
1984-01-01T23:59:59.000Z
A frequency domain (harmonic) finite element model is developed for the numerical prediction of depth average circulation within small embayments. Such embayments are often characterized by irregular boundaries and bottom ...
Finite element decomposition and grid generation for brain modeling and visualization
Batte, David Allan
1997-01-01T23:59:59.000Z
Numerical grid generation is used to provide a framework for brain and neuron visualization. Smoothing spline surfaces are fit to contour data to generate 3D solid model reconstruction of brain tissues. Finite element methods are then used...
Raman, Sethu
surfaceatmosphere exchanges in mesoscale air pollution systems Devdutta S. Niyogi & Sethu Raman NorthMesoscale Atmospheric Dispersion, 2001, Ed. Z. Boybeyi, WIT Publications, Southampton, UK, Advances in Air Pollution, Vol 9, p. 424. Chapter 9 Numerical modeling of gas deposition and bi- directional
Decoupled Modeling of Chilled Water Cooling Coils Using a Finite Element Method
Wang, G.; Liu, M.
2005-01-01T23:59:59.000Z
Decoupled Modeling of Chilled Water Cooling Coils Using a Finite Element Method Gang Wang Research Associate University of Nebraska Lincoln Mingsheng Liu Professor University of Nebraska Lincoln David E. Claridge Professor Texas A... be decoupled using a constant sensible heat ratio (SHR) and the saturation humidity ratio vs. temperature curve can be treated as linear in a small area corresponding to a finite element of the coil. This paper presents the decoupled cooling coil model...
A finite element model for laminated composite plates with matrix cracks and delaminations
Buie, Kevin Daniel
1988-01-01T23:59:59.000Z
A FINITE ELEMENT MODEL FOR LAMINATED COMPOSITE PLATES WITH MATRIX CRACKS AND DELAMINATIONS A Thesis by KEVIN DANIEL BUIE Submitted to the Office of Graduate Studies of Texas ASM University in partial fulfillment of' the requirements... for the degree of MASTER OF SCIENCE December 1988 Major Subject: Aerospace Engineering A FINITE ELEMENT MODEL FOR LAMINATED COMPOSITE PLATES WITH MATRIX CRACKS AND DELAMINATIONS A Thesis by KEVIN DANIEL BUIE Approved as to style and content by: David H...
A Finite Element Algorithm of a Nonlinear Diffusive Climate Energy Balance Model
Díaz, Jesús Ildefonso
A Finite Element Algorithm of a Nonlinear Diffusive Climate Energy Balance Model R. BERMEJO,1 J. This model belongs to the category of energy balance models introduced independently by the climatologists M climate. The energy balance model we are dealing with consists of a two-dimensional nonlinear parabolic
Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert; Gao, Fei; Sun, Xin; Tonks, Michael; Biner, Bullent; Millet, Paul; Tikare, Veena; Radhakrishnan, Balasubramaniam; Andersson , David
2012-04-11T23:59:59.000Z
A study was conducted to evaluate the capabilities of different numerical methods used to represent microstructure behavior at the mesoscale for irradiated material using an idealized benchmark problem. The purpose of the mesoscale benchmark problem was to provide a common basis to assess several mesoscale methods with the objective of identifying the strengths and areas of improvement in the predictive modeling of microstructure evolution. In this work, mesoscale models (phase-field, Potts, and kinetic Monte Carlo) developed by PNNL, INL, SNL, and ORNL were used to calculate the evolution kinetics of intra-granular fission gas bubbles in UO2 fuel under post-irradiation thermal annealing conditions. The benchmark problem was constructed to include important microstructural evolution mechanisms on the kinetics of intra-granular fission gas bubble behavior such as the atomic diffusion of Xe atoms, U vacancies, and O vacancies, the effect of vacancy capture and emission from defects, and the elastic interaction of non-equilibrium gas bubbles. An idealized set of assumptions was imposed on the benchmark problem to simplify the mechanisms considered. The capability and numerical efficiency of different models are compared against selected experimental and simulation results. These comparisons find that the phase-field methods, by the nature of the free energy formulation, are able to represent a larger subset of the mechanisms influencing the intra-granular bubble growth and coarsening mechanisms in the idealized benchmark problem as compared to the Potts and kinetic Monte Carlo methods. It is recognized that the mesoscale benchmark problem as formulated does not specifically highlight the strengths of the discrete particle modeling used in the Potts and kinetic Monte Carlo methods. Future efforts are recommended to construct increasingly more complex mesoscale benchmark problems to further verify and validate the predictive capabilities of the mesoscale modeling methods used in this study.
Cheng, Hao
2006-10-30T23:59:59.000Z
sensitivity computation of the streamline models with the versatility of finite-difference simulation was developed. Use of finite-difference simulation can account for complex physics. Finally, we developed an approach to history matching three-phase flow...
FINITE VOLUME METHODS APPLIED TO THE COMPUTATIONAL MODELLING OF WELDING PHENOMENA
Taylor, Gary
1 FINITE VOLUME METHODS APPLIED TO THE COMPUTATIONAL MODELLING OF WELDING PHENOMENA Gareth A.Taylor@brunel.ac.uk ABSTRACT This paper presents the computational modelling of welding phenomena within a versatile numerical) and Computational Solid Mechanics (CSM). With regard to the CFD modelling of the weld pool fluid dynamics, heat
Buscaglia, Gustavo C.
Conservative one-dimensional finite volume discretization of a new cavitation model for piston Cavitation ElrodAdams model Pistonrings a b s t r a c t This paper presents a conservative numerical implementation of a new cavitation model that is well suited for lubrication problems with cavitated regions
Isothermal model of ICF burn with finite alpha range treatment
Galloway, Conner Daniel (Conner Daniel Cross)
2009-01-01T23:59:59.000Z
A simple model for simulating deuterium tritium burn in inertial confinement fusion capsules is developed. The model, called the Isothermal Rarefaction Model, is zero dimensional (represented as ordinary differential ...
Schlegel, Nicole-Jeanne
2011-01-01T23:59:59.000Z
in running RCMs over Greenland to produce high-qualityoutlet glaciers. For Greenland, this detail is specificallyCurrently, no coupled Greenland Ice Sheet model experiment
Nuclear mass systematics by complementing the Finite Range Droplet Model with neural networks
S. Athanassopoulos; E. Mavrommatis; K. A. Gernoth; J. W. Clark
2005-11-30T23:59:59.000Z
A neural-network model is developed to reproduce the differences between experimental nuclear mass-excess values and the theoretical values given by the Finite Range Droplet Model. The results point to the existence of subtle regularities of nuclear structure not yet contained in the best microscopic/phenomenological models of atomic masses. Combining the FRDM and the neural-network model, we create a hybrid model with improved predictive performance on nuclear-mass systematics and related quantities.
Reading, University of
in the Lokal Modell (LM) can be found in Doms et al. (2004). Here a short summary of the cloud physics is given-scale clouds Since 26th of April 2004 the Lokal Modell (LM) uses a two-category ice scheme which explicitly S that are considered in this two-category ice scheme of LM. The individual microphysical processes are: Sc condensation
A Mixed Finite-Element Discretization of the Energy-Transport Model for Semiconductors
Pietra, Paola
A Mixed Finite-Element Discretization of the Energy-Transport Model for Semiconductors Stefan Holst #12;tting mixed #12;nite-element method is used to discretize the stationary energy. Energy-transport models describe the ow of electrons through a semi- conductor device, in uenced by di
Finite-element discretization of a linearized 2 -D model for lubricated oil transportation
Frey, Pascal
Finite-element discretization of a linearized 2 - D model for lubricated oil transportation V acts as a lubricant by coating the wall of the pipeline, thus preventing the oil from adhering is devoted to the numerical simulation of a linearized model for the lubricated trans- portation of heavy
On a tensor-based finite element model for the analysis of shell structures
Arciniega Aleman, Roman Augusto
2006-04-12T23:59:59.000Z
In the present study, we propose a computational model for the linear and nonlinear analysis of shell structures. We consider a tensor-based finite element formulation which describes the mathematical shell model in a natural and simple way by using...
Modeling the Effect of Finite-Rate Hydrogen Diffusion on Porosity Formation in Aluminum Alloys
Beckermann, Christoph
Modeling the Effect of Finite-Rate Hydrogen Diffusion on Porosity Formation in Aluminum Alloys KENT of hydrogen in the melt is developed to predict pore formation during the solidification of aluminum alloys by Lee et al.[3] Recent examples of porosity models for aluminum alloy castings, including the effect
A Finite-Element Model for Simulation of Carbon Dioxide Sequestration
Bao, Jie; Xu, Zhijie; Fang, Yilin
2014-09-01T23:59:59.000Z
Herein, we present a coupled thermal-hydro-mechanical model for geological sequestration of carbon dioxide followed by the stress, deformation, and shear-slip failure analysis. This fully coupled model considers the geomechanical response, fluid flow, and thermal transport relevant to geological sequestration. Both analytical solutions and numerical approach via finite element model are introduced for solving the thermal-hydro-mechanical model. Analytical solutions for pressure, temperature, deformation, and stress field were obtained for a simplified typical geological sequestration scenario. The finite element model is more general and can be used for arbitrary geometry. It was built on an open-source finite element code, Elmer, and was designed to simulate the entire period of CO2 injection (up to decades) both stably and accuratelyeven for large time steps. The shear-slip failure analysis was implemented based on the numerical results from the finite element model. The analysis reveals the potential failure zone caused by the fluid injection and thermal effect. From the simulation results, the thermal effect is shown to enhance well injectivity, especially at the early time of the injection. However, it also causes some side effects, such as the appearance of a small failure zone in the caprock. The coupled thermal-hydro-mechanical model improves prediction of displacement, stress distribution, and potential failure zone compared to the model that neglects non-isothermal effects, especially in an area with high geothermal gradient.
Daniels, Megan Hanako
2010-01-01T23:59:59.000Z
compressible numerical weather prediction model incompressible numerical weather prediction model withcompressible numerical weather prediction model in
Postulated Mesoscale Quantum of Internal Friction Hysteresis
Randall D. Peters
2004-05-27T23:59:59.000Z
Evidence is provided, from yet another experiment, for the existence of a mesoscale quantum of internal friction hysteresis, having the value of the electron rest energy divided by the fine structure constant.
Heat Transport in Groundwater Systems--Finite Element Model
Grubaugh, E. K.; Reddell, D. L.
into groundwater aquifers for long term energy storage. Analytical solutions are available that predict water temperatures as hot water is injected into a groundwater aquifer, but little field and laboratory data are available to verify these models. The objectives...
Finite Element Modeling of the Fastening Systems and the Concrete
Barkan, Christopher P.L.
Sleeper and Ballast 0 500 1000 1500 2000 2500 3000 3500 4000 0.0000 0.0002 0.0004 0.0006 0.0008 0 of strands Rail seat area is between 0.39 m to 0.67 m Rail Seat Area Component Modeling: Concrete Sleeper Seat Area Position of concrete surface strain lt = 0.48 m Component Modeling: Concrete Sleeper
Development of a finite element model of decompressive craniectomy
Fletcher, Tim L.; Kolias, Angelos G.; Hutchinson, Peter J. A.; Sutcliffe, Michael P. F.
2014-07-15T23:59:59.000Z
of high strains were comparatively small. Mesh. Axi-symmetric quadratic elements with reduced inte- gration (Abaqus element CAX8RPH) were used in all FE models. A fine mesh was created directly under the craniectomy edge with an average element length of 0...
Finite Element Modeling of Rate-Dependent Ratcheting in Granular Materials
Paris-Sud XI, Universit de
Finite Element Modeling of Rate-Dependent Ratcheting in Granular Materials A. Karrech a,, A. Seibi thrust is the introduc- tion of the "Chicago" law in a continuum approach to account for the ratcheting or jointly with the ratcheting effect. Non-associated plasticity is adopted since the paper mainly targets
Meson properties in a nonlocal SU(3) chiral quark model at finite temperature
Contrera, G. A. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Physics Department, Centro Atomico Constituyentes, Buenos Aires (Argentina); Gomez Dumm, D. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); IFLP, Dpto. de Fisica, Universidad Nacional de La Plata, C.C. 67, (1900) La Plata (Argentina); Scoccola, N. N. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, 1078 Buenos Aires (Argentina)
2010-11-12T23:59:59.000Z
Finite temperature meson properties are studied in the context of a nonlocal SU(3) quark model which includes flavor mixing and the coupling of quarks to the Polyakov loop (PL). We analyze the behavior of scalar and pseudoscalar meson masses and mixing angles, as well as quark-meson couplings and pseudoscalar meson decay constants.
Finite-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water
Kurganov, Alexander
Finite-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water Alina Chertock of shallow water equations and the pollutant propagation is described by a transport equation. The idea and the pollution computations: the shallow water equations are numerically integrated using a #12;nite- volume
A Finite Element Model for Ice Ball Evolution in a Multi-probe Cryosurgery
Wan, Richard G.
to intracellular ice injury for fast cooling rates, and solution effects injury for slow cooling rates. BasicallyA Finite Element Model for Ice Ball Evolution in a Multi-probe Cryosurgery RICHARD WANa, *, ZHIHONG October 2002; In final form 8 May 2003) The ice formation in a water body is examined for the computation
A finite difference model for predicting sediment oxygen demand in streams
Charbonnet, Danielle Andrea
2003-01-01T23:59:59.000Z
in the representative river system using benthic chambers. A finite difference model was developed based on Fick's Law of Diffusion. Mass transfer principles are used to perform a mass balance on the oxygen concentrations in the sediment in order to determine SOD...
Modelling CO2 diffusion and assimilation in a leaf with axisymmetric finite volumes
Herbin, Raphaèle
Modelling CO2 diffusion and assimilation in a leaf with axisymmetric finite volumes Emily Gallouët. This paper deals with the numerical simulation of the diffusion and assimilation by photosynthesis of CO2 medium, from experimental measurements of the pointwise value of internal CO2 concentration, giving some
Suciu, Nicolae
A mixed finite element discretization scheme for a concrete carbonation model with concentration/unsaturated porous media. The special features of our problem are twofold: the reaction produces water and therefore for the case of concrete carbonation one of the most important physico-chemical processes affecting
Finite-temperature order-disorder phase transition in a cluster model of decagonal tilings
Ghler, Franz
phase,2 because its phason degrees of freedom are frozen (locked). The high-temperature state is accordingly called unlocked phase. Here, the thermal energy is suffi- ciently high to excite the phasonFinite-temperature order-disorder phase transition in a cluster model of decagonal tilings Michael
Propagation of Kelvin waves along irregular coastlines in finite-difference models
Propagation of Kelvin waves along irregular coastlines in finite-difference models David J. Schwaba of Kelvin wave phase speed on offshore grid resolution and propagation direction relative to the numerical propagating along a straight coastline; (2) Kelvin wave propagating at a 45 angle to the numerical grid along
Modeling of board-level package by Finite Element Analysis and laser interferometer measurements
Cao, Wenwu
and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai be simulated by an equivalent Finite Element Analysis (FEA) model of the board-level package, in which detailed layer structure of the Print Circuit Board (PCB), signal wires and through-holes were ignored
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
Three-dimensional finite difference time domain modeling of the Schumann resonance
Pasko, Victor
Three-dimensional finite difference time domain modeling of the Schumann resonance parameters to as Schumann resonances and are excited by lightning discharges. The detection of such resonances on other frequency propagation is employed to study the Schumann resonance problems on Titan, Venus, and Mars
TRAVELING WAVES IN A FINITE CONDENSATION RATE MODEL FOR STEAM INJECTION
Eindhoven, Technische Universiteit
TRAVELING WAVES IN A FINITE CONDENSATION RATE MODEL FOR STEAM INJECTION J. BRUINING AND C.J. VAN DUIJN Abstract. Steam drive recovery of oil is an economical way of producing oil even in times of low oil prices and is used world wide. This paper focuses on the one-dimensional setting, where steam
Thermodynamics and fluctuations of conserved charges in Hadron Resonance Gas model in finite volume
Bhattacharyya, Abhijit; Samanta, Subhasis; Sur, Subrata
2015-01-01T23:59:59.000Z
The thermodynamics of hot and dense matter created in heavy-ion collision experiments are usually studied as a system of infinite volume. Here we report on possible effects for considering a finite system size for such matter in the framework of the Hadron Resonance Gas model. The bulk thermodynamic variables as well as the fluctuations of conserved charges are considered. We find that the finite size effects are insignificant once the observables are scaled with the respective volumes. The only substantial effect is found in the fluctuations of electric charge which may therefore be used to extract information about the volume of fireball created in heavy-ion collision experiments.
Winding Transitions at Finite Energy and Temperature: An O(3) Model
Salman Habib; Emil Mottola; Peter Tinyakov
1996-08-14T23:59:59.000Z
Winding number transitions in the two dimensional softly broken O(3) nonlinear sigma model are studied at finite energy and temperature. New periodic instanton solutions which dominate the semiclassical transition amplitudes are found analytically at low energies, and numerically for all energies up to the sphaleron scale. The Euclidean period beta of these finite energy instantons increases with energy, contrary to the behavior found in the abelian Higgs model or simple one dimensional systems. This results in a sharp crossover from instanton dominated tunneling to sphaleron dominated thermal activation at a certain critical temperature. Since this behavior is traceable to the soft breaking of conformal invariance by the mass term in the sigma model, semiclassical winding number transition amplitudes in the electroweak theory in 3+1 dimensions should exhibit a similar sharp crossover. We argue that this is indeed the case in the standard model for M_H < 4 M_W.
Puckett, A.D.
2000-09-01T23:59:59.000Z
The ability to model wave propagation in circular cylindrical bars of finite length numerically or analytically has many applications. In this thesis the capability of an explicit finite element method to model longitudinal waves in cylindrical rods with circular cross-sections is explored. Dispersion curves for the first four modes are compared to the analytical solution to determine the accuracy of various element sizes and time steps. Values for the time step and element size are determined that retain accuracy while minimizing computational time. The modeling parameters are validated by calculating a signal propagated with a broadband input force. Limitations on the applicability are considered along with modeling parameters that should be applicable to more general geometries.
Boyer, Edmond
identification method - associating a direct finite element model of Gleeble tests and an optimization module1 Inverse Finite Element Modelling and Identification of Constitutive Parameters of UHS Steel Based-2 ) hc heat transfer coefficient at interface between specimen and grips (W m-2 K) hth_eff effective
Quark matter and meson properties in a Nonlocal SU(3) chiral quark model at finite temperature
Gomez Dumm, D., E-mail: dumm@fisica.unlp.edu.ar [UNLP, IFLP, Departamento de Fisica (Argentina); Contrera, G. A., E-mail: contrera@tandar.cnea.gov.ar [CONICET (Argentina)
2012-06-15T23:59:59.000Z
We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with a background color field. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles, and decay constants.
Critical analysis of quark-meson coupling models for nuclear matter and finite nuclei
Horst Mueller; Byron K. Jennings
1998-07-09T23:59:59.000Z
Three versions of the quark-meson coupling (QMC) model are applied to describe properties of nuclear matter and finite nuclei. The models differ in the treatment of the bag constant and in terms of nonlinear scalar self-interactions. As a consequence opposite predictions for the medium modifications of the internal nucleon structure arise. After calibrating the model parameters at equilibrium nuclear matter density, binding energies, charge radii, single-particle spectra and density distributions of spherical nuclei are analyzed and compared with QHD calculations. For the models which predict a decreasing size of the nucleon in the nuclear environment, unrealistic features of the nuclear shapes arise.
Building relativistic mean field models for finite nuclei and neutron stars
Wei-Chia Chen; J. Piekarewicz
2014-08-18T23:59:59.000Z
Background: Theoretical approaches based on density functional theory provide the only tractable method to incorporate the wide range of densities and isospin asymmetries required to describe finite nuclei, infinite nuclear matter, and neutron stars. Purpose: A relativistic energy density functional (EDF) is developed to address the complexity of such diverse nuclear systems. Moreover, a statistical perspective is adopted to describe the information content of various physical observables. Methods: We implement the model optimization by minimizing a suitably constructed chi-square objective function using various properties of finite nuclei and neutron stars. The minimization is then supplemented by a covariance analysis that includes both uncertainty estimates and correlation coefficients. Results: A new model, FSUGold2, is created that can well reproduce the ground-state properties of finite nuclei, their monopole response, and that accounts for the maximum neutron star mass observed up to date. In particular, the model predicts both a stiff symmetry energy and a soft equation of state for symmetric nuclear matter--suggesting a fairly large neutron-skin thickness in Pb208 and a moderate value of the nuclear incompressibility. Conclusions: We conclude that without any meaningful constraint on the isovector sector, relativistic EDFs will continue to predict significantly large neutron skins. However, the calibration scheme adopted here is flexible enough to create models with different assumptions on various observables. Such a scheme--properly supplemented by a covariance analysis--provides a powerful tool to identify the critical measurements required to place meaningful constraints on theoretical models.
Simulation of dynamic fracture using peridynamics, finite element modeling, and contact.
Littlewood, David John
2010-11-01T23:59:59.000Z
Peridynamics is a nonlocal extension of classical solid mechanics that allows for the modeling of bodies in which discontinuities occur spontaneously. Because the peridynamic expression for the balance of linear momentum does not contain spatial derivatives and is instead based on an integral equation, it is well suited for modeling phenomena involving spatial discontinuities such as crack formation and fracture. In this study, both peridynamics and classical finite element analysis are applied to simulate material response under dynamic blast loading conditions. A combined approach is utilized in which the portion of the simulation modeled with peridynamics interacts with the finite element portion of the model via a contact algorithm. The peridynamic portion of the analysis utilizes an elastic-plastic constitutive model with linear hardening. The peridynamic interface to the constitutive model is based on the calculation of an approximate deformation gradient, requiring the suppression of possible zero-energy modes. The classical finite element portion of the model utilizes a Johnson-Cook constitutive model. Simulation results are validated by direct comparison to expanding tube experiments. The coupled modeling approach successfully captures material response at the surface of the tube and the emerging fracture pattern. The coupling of peridynamics and finite element analysis via a contact algorithm has been shown to be a viable means for simulating material fracture in a high-velocity impact experiment. A combined peridynamics/finite element approach was applied to model an expanding tube experiment performed by Vogler, et al., in which loading on the tube is a result of Lexan slugs impacting inside the tube. The Lexan portion of the simulation was modeled with finite elements and a Johnson-Cook elastic-plastic material model in conjunction with an equation-of-state law. The steel tube portion of the simulation was modeled with peridynamics, an elastic-plastic material model, and a critical stretch bond damage model. The application of peridynamics to the tube portion of the model allowed the capture of the formation of cracks and eventual fragmentation of the tube. The simulation results yielded good agreement with the experimental results published by Vogler, et al., for the velocity and displacement profiles on the surface of the tube and the resulting fragment distribution. Numerical difficulties were encountered that required removal of hexahedron elements from the Lexan portion of the model over the course of the simulation. The significant number of inverted and nearly-inverted elements appearing over the course of the simulation is believed to be a result of irregularities in the contact between the Lexan and AerMet portions of the model, and was likely exacerbated by the ultra-high strength of the AerMet tube. Future simulations are planned in which the Lexan portion of the simulation is modeled with peridynamics, or with an alternative method such as smoothed particle hydrodynamics, with the goal of reducing these numerical difficulties.
Leng, Wei [Chinese Academy of Sciences; Ju, Lili [University of South Carolina; Gunzburger, Max [Florida State University; Price, Stephen [Los Alamos National Laboratory; Ringler, Todd [Los Alamos National Laboratory,
2012-01-01T23:59:59.000Z
The numerical modeling of glacier and ice sheet evolution is a subject of growing interest, in part because of the potential for models to inform estimates of global sea level change. This paper focuses on the development of a numerical model that determines the velocity and pressure fields within an ice sheet. Our numerical model features a high-fidelity mathematical model involving the nonlinear Stokes system and combinations of no-sliding and sliding basal boundary conditions, high-order accurate finite element discretizations based on variable resolution grids, and highly scalable parallel solution strategies, all of which contribute to a numerical model that can achieve accurate velocity and pressure approximations in a highly efficient manner. We demonstrate the accuracy and efficiency of our model by analytical solution tests, established ice sheet benchmark experiments, and comparisons with other well-established ice sheet models.
Temporal Changes in Wind as Objects for Evaluating Mesoscale Numerical Weather Prediction
Knievel, Jason Clark
a method of evaluating numerical weather prediction models by comparing the characteristics of temporal for biases in features forecast by the model. 1. Introduction Verification of numerical weather predictionTemporal Changes in Wind as Objects for Evaluating Mesoscale Numerical Weather Prediction DARAN L
Modeling of reactor components using FIDAP: a finite element computer code
Gangadharan, Anand
1989-01-01T23:59:59.000Z
of MASTER OF SCIENCE May 1989 Major Subject: Nuclear Engineering MODELING OF REACTOR COMPONENTS USING FIDAP - A FINITE ELEMENT COMPUTER CODE A Thesis by ANAND GANGADHARAN Approved as to style and content by. assin A. Hassan (Chair of Committee... of Nuclear Engineering, Texas ASM University. I feel elated in placing on record, my direct and totally involved interaction with the Chairman of my committee, Prof. Y. A. Hassan. I am grateful to him for his constant and unreserved encouragement...
Boyer, Edmond
- 1 - Implementation of surface tension with wall adhesion effects in a three-dimensional finite element modelling of surface tension. The external stress vectors associated with surface tension a drop of liquid on a plane is treated. Keywords : surface tension, finite element method, average
Hoofard, Michael Eugene
1986-01-01T23:59:59.000Z
MESOSCALE CONVECTIVE CCMPLLX VS. NON-MESOSCALE CONVECTIVE COMPLEX THUNDERSTORMS: A COMPARISON OF SELECTED METEOROLOGICAL VARIABLES A Thesis MICHAkL EUGENE JJOOFARD Submitted to the Graduate College of Texas AJkM University in partial... by MICHAEL EUGENE HOOFARD Approved as to style and content by: a ter . enry (Chairman of Committee) %~5 44 c5 c usan gur c (Member) ona . oc ing (Member) ames . cogg (Head of Department) August 1986 ABSTRACT Nesoscale Convective Complex vs. Non...
Parallel 3D Finite Element Numerical Modelling of DC Electron Guns
Prudencio, E.; Candel, A.; Ge, L.; Kabel, A.; Ko, K.; Lee, L.; Li, Z.; Ng, C.; Schussman, G.; /SLAC
2008-02-04T23:59:59.000Z
In this paper we present Gun3P, a parallel 3D finite element application that the Advanced Computations Department at the Stanford Linear Accelerator Center is developing for the analysis of beam formation in DC guns and beam transport in klystrons. Gun3P is targeted specially to complex geometries that cannot be described by 2D models and cannot be easily handled by finite difference discretizations. Its parallel capability allows simulations with more accuracy and less processing time than packages currently available. We present simulation results for the L-band Sheet Beam Klystron DC gun, in which case Gun3P is able to reduce simulation time from days to some hours.
Efficient Computation of Info-Gap Robustness for Finite Element Models
Stull, Christopher J. [Los Alamos National Laboratory; Hemez, Francois M. [Los Alamos National Laboratory; Williams, Brian J. [Los Alamos National Laboratory
2012-07-05T23:59:59.000Z
A recent research effort at LANL proposed info-gap decision theory as a framework by which to measure the predictive maturity of numerical models. Info-gap theory explores the trade-offs between accuracy, that is, the extent to which predictions reproduce the physical measurements, and robustness, that is, the extent to which predictions are insensitive to modeling assumptions. Both accuracy and robustness are necessary to demonstrate predictive maturity. However, conducting an info-gap analysis can present a formidable challenge, from the standpoint of the required computational resources. This is because a robustness function requires the resolution of multiple optimization problems. This report offers an alternative, adjoint methodology to assess the info-gap robustness of Ax = b-like numerical models solved for a solution x. Two situations that can arise in structural analysis and design are briefly described and contextualized within the info-gap decision theory framework. The treatments of the info-gap problems, using the adjoint methodology are outlined in detail, and the latter problem is solved for four separate finite element models. As compared to statistical sampling, the proposed methodology offers highly accurate approximations of info-gap robustness functions for the finite element models considered in the report, at a small fraction of the computational cost. It is noted that this report considers only linear systems; a natural follow-on study would extend the methodologies described herein to include nonlinear systems.
Howat, Ian M.
and logistical needs and has helped advance polar numerical weather prediction as well as understanding support for the USAP. The concern at the time was the numerical weather prediction (NWP) guidance-time implementation of the Weather Research and Forecasting model (WRF; Skamarock et al. 2008) to support the U
Chaboureau, Jean-Pierre
, tests made with three different values of an ice to snow autoconversion threshold reveal a profound-scale cloudiness in the model. A similar test conducted on the ice water and the liquid water paths confirms and water vapor. Once cloud is formed, however, it is the role of the microphysical scheme to parameterize
Heymsfield, A.
1997-09-01T23:59:59.000Z
The overall purpose of this research was to exploit measurements in clouds sampled during several field programs, especially from experiments in tropical regions, in a four-component study to develop and validate cloud parameterizations for general circulation models, emphasizing ice clouds. The components were: (1) parameterization of basic properties of mid- and upper-tropospheric clouds, such as condensed water content, primarily with respect to cirrus from tropical areas; (2) the second component was to develop parameterizations which express cloud radiative properties in terms of basic cloud microphysical properties, dealing primarily with tropical oceanic cirrus clouds and continental thunderstorm anvils, but also including altocumulus clouds; (3) the third component was to validate the parameterizations through use of ground-based measurements calibrated using existing and planned in-situ measurements of cloud microphysical properties and bulk radiative properties, as well as time-resolved data collected over extended periods of time; (4) the fourth component was to implement the parameterizations in the National Center for Atmospheric Research (NCAR) community climate model (CCM) II or in the NOAA-GFDL model (by L. Donner GFDL) and to perform sensitivity studies.
Barham, M; White, D; Steigmann, D; Rudd, R
2009-04-08T23:59:59.000Z
Recently a new class of biocompatible elastic polymers loaded with small ferrous particles (magnetoelastomer) was developed at Lawrence Livermore National Laboratory. This new material was formed as a thin film using spin casting. The deformation of this material using a magnetic field has many possible applications to microfluidics. Two methods will be used to calculate the deformation of a circular magneto-elastomeric film subjected to a magnetic field. The first method is an arbitrary Lagrangian-Eulerian (ALE) finite element method (FEM) and the second is based on nonlinear continuum electromagnetism and continuum elasticity in the membrane limit. The comparison of these two methods is used to test/validate the finite element method.
Universal Model of Finite-Reynolds Number Turbulent Flow in Channels and Pipes
Victor S. L'vov; Itamar Procaccia; Oleksii Rudenko
2007-12-07T23:59:59.000Z
In this Letter we suggest a simple and physically transparent analytical model of the pressure driven turbulent wall-bounded flows at high but finite Reynolds numbers Re. The model gives accurate qualitative description of the profiles of the mean-velocity and Reynolds-stresses (second order correlations of velocity fluctuations) throughout the entire channel or pipe in the wide range of Re, using only three Re-independent parameters. The model sheds light on the long-standing controversy between supporters of the century-old log-law theory of von-K\\`arm\\`an and Prandtl and proposers of a newer theory promoting power laws to describe the intermediate region of the mean velocity profile.
Finite Mixture of ARMA-GARCH Model for Stock Price Prediction Him Tang, Kai-Chun Chiu and Lei Xu
Xu, Lei
Finite Mixture of ARMA-GARCH Model for Stock Price Prediction Him Tang, Kai-Chun Chiu and Lei Xu mixture of autore- gressive generalized autoregressive conditional het- eroscedasticity (AR-GARCH) models to extend the mixture of AR-GARCH model (W.C. Wong, F. Yip and L. Xu, 1998) to the mixture of ARMA- GARCH
Plotkin, Steven S.
Correlated energy landscape model for finite, random heteropolymers Steven S. Plotkin, Jin Wang landscape or random energy model REM estimates. A tricritical point is obtained where behavior of the order has been derived from the study of the most rugged energy landscape, the so-called random energy model
Finite Element Analysis of the Amontons-Coulomb's Model using Local and Global Friction Tests
Oliveira, M. C.; Menezes, L. F.; Ramalho, A. [CEMUC, Department of Mechanical Engineering, University of Coimbra, Polo II, Rua Luis Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra (Portugal); Alves, J. L. [Department of Mechanical Engineering, University of Minho, Campus de Azurem, 4800-058, Guimaraes (Portugal)
2011-05-04T23:59:59.000Z
In spite of the abundant number of experimental friction tests that have been reported, the contact with friction modeling persists to be one of the factors that determine the effectiveness of sheet metal forming simulation. This difficulty can be understood due to the nature of the friction phenomena, which comprises the interaction of different factors connected to both sheet and tools' surfaces. Although in finite element numerical simulations friction models are commonly applied at the local level, they normally rely on parameters identified based on global experimental tests results. The aim of this study is to analyze the applicability of the Amontons-Coulomb's friction coefficient identified using complementary tests: (i) load-scanning, at the local level and (ii) draw-bead, at the global level; to the numerical simulation of sheet metal forming processes.
The Casimir force on a piston at finite temperature in Randall-Sundrum models
Hongbo Cheng
2011-12-29T23:59:59.000Z
The Casimir effect for a three-parallel-plate system at finite temperature within the frame of five-dimensional Randall-Sundrum models is studied. In the case of Randall-Sundrum model involving two branes we find that the Casimir force depends on the plates distance and temperature after one outer plate has been moved to the distant place. Further we discover that the sign of the reduced force is negative as the plate and piston locate very close, but the reduced force nature becomes repulsive when the plates distance is not very tiny and finally the repulsive force vanishes with extremely large plates separation. The thermal influence causes the repulsive Casimir force greater. Within the frame of one-brane scenario the reduced Casimir force between the piston and one plate left keeps attractive no matter how high the temperature is. It is interesting that the thermal effect leads the attractive Casimir force greater instead of changing the force nature.
Analysis of Refrigerant Flow and Deformation for a Flexible Short-Tube using a Finite Element Model
O'Neal, D.L.; Bassiouny, R.
reliability. Short-tubes have either a constant inner dia- meter flow channel or a tapered channel with a smallAbstract A finite element model was used to simulate single-phase flow of R-22 through flexible short-tubes. The numerical model included the fluid... in the flow area. The more flexible (5513 kPa) short-tube restricted the mass flow rate more than the most rigid (9889 kPa) short-tube used in this study. The mass flow rates estimated with the finite element model were as much as 14% higher than those from...
Phase Reduction Models for Improving the Accuracy of the Finite Element Solution of
Boyer, Edmond
, acoustic scattering, short-wave problem, finite element method, pollution, accuracy, On-Surface Radiation in view of a numerical finite element solution. It is well-known that pollution error causes inaccuracies the pollution error in the finite element solution of time-harmonic scattering problems. The pollution error
Dynamical aspects of the plane-wave matrix model at finite temperature
Naoyuki Kawahara; Jun Nishimura; Kentaroh Yoshida
2006-04-25T23:59:59.000Z
We study dynamical aspects of the plane-wave matrix model at finite temperature. One-loop calculation around general classical vacua is performed using the background field method, and the integration over the gauge field moduli is carried out both analytically and numerically. In addition to the trivial vacuum, which corresponds to a single M5-brane at zero temperature, we consider general static fuzzy-sphere type configurations. They are all 1/2 BPS, and hence degenerate at zero temperature due to supersymmetry. This degeneracy is resolved, however, at finite temperature, and we identify the configuration that gives the smallest free energy at each temperature. The Hagedorn transition in each vacuum is studied by using the eigenvalue density method for the gauge field moduli, and the free energy as well as the Polyakov line is obtained analytically near the critical point. This reveals the existence of fuzzy sphere phases, which may correspond to the plasma-ball phases in N=4 SU(\\infty) SYM on S^1 X S^3. We also perform Monte Carlo simulation to integrate over the gauge field moduli. While this confirms the validity of the analytic results near the critical point, it also shows that the trivial vacuum gives the smallest free energy throughout the high temperature regime.
FINITE RATE OF INNOVATION BASED MODELING AND COMPRESSION OF ECG G. Baechler N. Freris R.F. Quick
Dalang, Robert C.
FINITE RATE OF INNOVATION BASED MODELING AND COMPRESSION OF ECG SIGNALS G. Baechler N. Freris R and compress ECG signals. This technique generalizes classical FRI estimation to enable the use of a sum of asym- metric Cauchy-based pulses for modeling electrocardiogram (ECG) signals. We experimentally show
Hyperbolic reformulation of a 1D viscoelastic blood flow model and ADER finite volume schemes
Montecinos, Gino I.; Mller, Lucas O.; Toro, Eleuterio F.
2014-06-01T23:59:59.000Z
The applicability of ADER finite volume methods to solve hyperbolic balance laws with stiff source terms in the context of well-balanced and non-conservative schemes is extended to solve a one-dimensional blood flow model for viscoelastic vessels, reformulated as a hyperbolic system, via a relaxation time. A criterion for selecting relaxation times is found and an empirical convergence rate assessment is carried out to support this result. The proposed methodology is validated by applying it to a network of viscoelastic vessels for which experimental and numerical results are available. The agreement between the results obtained in the present paper and those available in the literature is satisfactory. Key features of the present formulation and numerical methodologies, such as accuracy, efficiency and robustness, are fully discussed in the paper.
Quantum-corrected drift-diffusion models: Solution fixed point map and finite element approximation
Falco, Carlo de [School of Mathematical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Jerome, Joseph W. [Department of Mathematics, Northwestern University, 2033 Sheridan Road, Evanston, IL 60208-2730 (United States); Sacco, Riccardo [Dipartimento di Matematica 'F.Brioschi', Politecnico di Milano, via Bonardi 9, 20133 Milano (Italy)], E-mail: riccardo.sacco@polimi.it
2009-03-20T23:59:59.000Z
This article deals with the analysis of the functional iteration, denoted Generalized Gummel Map (GGM), proposed in [C. de Falco, A.L. Lacaita, E. Gatti, R. Sacco, Quantum-Corrected Drift-Diffusion Models for Transport in Semiconductor Devices, J. Comp. Phys. 204 (2) (2005) 533-561] for the decoupled solution of the Quantum Drift-Diffusion (QDD) model. The solution of the problem is characterized as being a fixed point of the GGM, which permits the establishment of a close link between the theoretical existence analysis and the implementation of a numerical tool, which was lacking in previous non-constructive proofs [N.B. Abdallah, A. Unterreiter, On the stationary quantum drift-diffusion model, Z. Angew. Math. Phys. 49 (1998) 251-275, R. Pinnau, A. Unterreiter, The stationary current-voltage characteristics of the quantum drift-diffusion model, SIAM J. Numer. Anal. 37 (1) (1999) 211-245]. The finite element approximation of the GGM is illustrated, and the main properties of the numerical fixed point map (discrete maximum principle and order of convergence) are discussed. Numerical results on realistic nanoscale devices are included to support the theoretical conclusions.
Kirchner, James W.
Inferring catchment precipitation by doing hydrology backward: A test in 24 small and mesoscale September 2012; published 10 October 2012. [1] The complexity of hydrological systems and the necessary simplification of models describing these systems remain major challenges in hydrological modeling. Kirchner
Contrera, G. A. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, (1429) Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Dumm, D. Gomez [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); IFLP, Dpto. de Fisica, Universidad Nacional de La Plata, C.C. 67, (1900) La Plata (Argentina); Scoccola, Norberto N. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, (1429) Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, (1078) Buenos Aires (Argentina)
2010-03-01T23:59:59.000Z
We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with the Polyakov loop. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles and decay constants. The critical temperature is found to be T{sub c{approx_equal}}202 MeV, in better agreement with lattice results than the value recently obtained in the local SU(3) PNJL model. It is seen that above T{sub c} pseudoscalar meson masses get increased, becoming degenerate with the masses of their chiral partners. The temperatures at which this matching occurs depend on the strange quark composition of the corresponding mesons. The topological susceptibility shows a sharp decrease after the chiral transition, signalling the vanishing of the U(1){sub A} anomaly for large temperatures.
Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.
Bower, Ward Isaac; Quintana, Michael A.; Johnson, Jay
2012-01-01T23:59:59.000Z
Arc faults in photovoltaic (PV) modules have caused multiple rooftop fires. The arc generates a high-temperature plasma that ignites surrounding materials and subsequently spreads the fire to the building structure. While there are many possible locations in PV systems and PV modules where arcs could initiate, bypass diodes have been suspected of triggering arc faults in some modules. In order to understand the electrical and thermal phenomena associated with these events, a finite element model of a busbar and diode was created. Thermoelectrical simulations found Joule and internal diode heating from normal operation would not normally cause bypass diode or solder failures. However, if corrosion increased the contact resistance in the solder connection between the busbar and the diode leads, enough voltage potentially would be established to arc across micron-scale electrode gaps. Lastly, an analytical arc radiation model based on observed data was employed to predicted polymer ignition times. The model predicted polymer materials in the adjacent area of the diode and junction box ignite in less than 0.1 seconds.
A finite element model for transient thermal/structural analysis of large composite space structures
Lutz, James Delmar
2012-06-07T23:59:59.000Z
on approximate 6 analysis techniques based on finite elements has begun. Such techniques as reduced basis techniques and generalized transform methods offer hope of solving the finite element 8 equations more efficiently. An integrated thermal/structural... integrated analysis codes. However, Mahaney, Thornton, and Dechaumphai have identified require 5 ments for such thermal/structural programs. They concluded that such analysis methods should have the following five characteristics. First, a common finite...
Demeio, Lucio
Virtual Laboratories > 12. Finite Sampling Models > 1 2 3 4 5 6 7 8 9 7. The Coupon Collector of a coupon collector: each time the collector buys a certain product (bubble gum or Cracker Jack, for example} In terms of the coupon collector, this random variable gives the number of products required to get k
Finite element modelling of transport and drift effects in tokamak divertor and SOL
Simard, M.; Marchand, R. [INRS-Energie et Materiaux, Varennes, Quebec (Canada); Boucher, C.; Gunn, J.P. [Centre Canadien de Fusion Magnetique, Varennes, Quebec (Canada)] [and others
1996-12-31T23:59:59.000Z
A finite element code is used to simulate transport of a single-species plasma in the edge and divertor of a tokamak. The physical model is based on Braginskii`s fluid equations for the conservation of particles, parallel momentum, ion and electron energy. In modelling recycling, transport of neutral density and energy is treated in the diffusion approximation. The electrostatic potential is obtained from the generalized Ohm`s law. It is used to compute the electric field and the associated E x B drift. In a first approximation, transport is assumed to be ambipolar. The system of equations is discretized on an unstructured triangular mesh, thus permitting good spatial resolution near the X-point and an accurate description of divertor plates of arbitrary shape. Special care must be taken to prevent numerical corruption of the highly anisotropic thermal diffusion. Comparisons will be made between simulations and experimental results from TdeV. This will focus, in particular, on density and temperature profiles at the divertor plates, and on the plasma parallel velocity in the SOL. The asymmetry in the power deposited to the inner and outer divertors and the effect of magnetic field reversal will be considered. Comparisons with B2-Eirene simulation results will also be presented.
Abreu, L. M.; Malbouisson, J. M. C. [Instituto de Fisica, Universidade Federal da Bahia, 40210-340, Salvador, BA (Brazil); Malbouisson, A. P. C. [Centro Brasileiro de Pesquisas Fisicas, MCT, 22290-180, Rio de Janeiro, RJ (Brazil)
2011-01-15T23:59:59.000Z
We investigate finite-size effects on the phase structure of chiral and difermion condensates at finite temperature and density in the framework of the two-dimensional large-N Nambu-Jona-Lasinio model. We take into account size-dependent effects by making use of zeta-function and compactification methods. The thermodynamic potential and the gap equations for the chiral and difermion condensed phases are then derived in the mean-field approximation. Size-dependent critical lines separating the different phases are obtained considering antiperiodic boundary conditions for the spatial coordinate.
Finite-size scaling in the quantum phase transition of the open-system Dicke-model
G. Konya; D. Nagy; G. Szirmai; P. Domokos
2012-06-22T23:59:59.000Z
Laser-driven Bose-Einstein condensate of ultracold atoms loaded into a lossy high-finesse optical resonator exhibits critical behavior and, in the thermodynamic limit, a phase transition between stationary states of different symmetries. The system realizes an open-system variant of the celebrated Dicke-model. We study the transition for a finite number of atoms by means of a Hartree-Fock-Bogoliubov method adapted to a damped-driven open system. The finite-size scaling exponents are determined and a clear distinction between the non-equilibrium and the equilibrium quantum criticality is found.
Tests of an ensemble Kalman filter for mesoscale and regional-scale data assimilation
Meng, Zhiyong
2007-09-17T23:59:59.000Z
technique with real observations (Houtekamer et al. 2005; Whitaker et al. 2006). However, the performance of the EnKF implemented in mesoscale models has not been compared directly to that of variational method. ____________ This dissertation follows... while perturbing the observation. However, the computation cost is very large when applying this method to high-degree- of-freedom systems. Whitaker and Hamill (2002) introduced the ensemble square-root filter (EnSRF) as a better way to deal...
Multiscale Modeling with Carbon Nanotubes
Maiti, A
2006-02-21T23:59:59.000Z
Technologically important nanomaterials come in all shapes and sizes. They can range from small molecules to complex composites and mixtures. Depending upon the spatial dimensions of the system and properties under investigation computer modeling of such materials can range from equilibrium and nonequilibrium Quantum Mechanics, to force-field-based Molecular Mechanics and kinetic Monte Carlo, to Mesoscale simulation of evolving morphology, to Finite-Element computation of physical properties. This brief review illustrates some of the above modeling techniques through a number of recent applications with carbon nanotubes: nano electromechanical sensors (NEMS), chemical sensors, metal-nanotube contacts, and polymer-nanotube composites.
Thompson, Anne
with small amount of moisture, dry dynamic gravity wave modes continue to dominate. However, convective-permitting simulations with the Weather Research and Forecast (WRF) model are performed to study mesoscale gravity waves/negative), and 7-km dynamic tropopause (turquoise lines). Wave Identification Figure 3. Comparison of WP5 at 132 h
Mesoscale Quantization and Self-Organized Stability
Randall D. Peters
2005-06-16T23:59:59.000Z
In the world of technology, one of the most important forms of friction is that of rolling friction. Yet it is one of the least studied of all the known forms of energy dissipation. In the present experiments we investigate the oscillatory free-decay of a rigid cube, whose side-length is less than the diameter of the rigid cylinder on which it rests. The resulting free-decay is one of harmonic motion with damping. The non-dissipative character of the oscillation yields to a linear differential equation; however, the damping is found to involve more than a deterministic nonlinearity. Dominated by rolling friction, the damping is sensitive to the material properties of the contact surfaces. For `clean' surfaces of glass on glass, the decay shows features of mesoscale quantization and self-organized stability.
Adaptive Finite Element Modeling Techniques for the Poisson-Boltzmann Equation
Michael Holst; James Andrew McCammon; Zeyun Yu; Yongcheng Zhou; Yunrong Zhu
2010-09-30T23:59:59.000Z
We develop an efficient and reliable adaptive finite element method (AFEM) for the nonlinear Poisson-Boltzmann equation (PBE). We first examine the regularization technique of Chen, Holst, and Xu; this technique made possible the first a priori pointwise estimates and the first complete solution and approximation theory for the Poisson-Boltzmann equation. It also made possible the first provably convergent discretization of the PBE, and allowed for the development of a provably convergent AFEM for the PBE. However, in practice the regularization turns out to be numerically ill-conditioned. In this article, we examine a second regularization, and establish a number of basic results to ensure that the new approach produces the same mathematical advantages of the original regularization, without the ill-conditioning property. We then design an AFEM scheme based on the new regularized problem, and show that the resulting AFEM scheme is accurate and reliable, by proving a contraction result for the error. This result, which is one of the first results of this type for nonlinear elliptic problems, is based on using continuous and discrete a priori pointwise estimates to establish quasi-orthogonality. To provide a high-quality geometric model as input to the AFEM algorithm, we also describe a class of feature-preserving adaptive mesh generation algorithms designed specifically for constructing meshes of biomolecular structures, based on the intrinsic local structure tensor of the molecular surface. The stability advantages of the new regularization are demonstrated using an FETK-based implementation, through comparisons with the original regularization approach for a model problem. The convergence and accuracy of the overall AFEM algorithm is also illustrated by numerical approximation of electrostatic solvation energy for an insulin protein.
Evolution of moisture convergence in a mesoscale convective complex
Bercherer, John Phillip
1990-01-01T23:59:59.000Z
Committee: Dr. Keuneth C. Brundidge Two separate Mesoscale Convective Complexes (MCCs) were investigated to determine if a characteristic surface moisture convergence (MC) signature existed on the mesoscale during their lifecycle. The first storm (Case 1... convergence, a bandpass filtering technique was utilized. It was found that MC could identify the general area of initial thunderstorm activity 2 h prior to its development for both cases. During the initial development stage of Case 1, advection...
Mesoscale phenomena in solutions of 3-methylpyridine, heavy water, and an antagonistic salt
Jan Leys; Deepa Subramanian; Eva Rodezno; Boualem Hammouda; Mikhail A. Anisimov
2013-08-22T23:59:59.000Z
We have investigated controversial issues regarding the mesoscale behavior of 3-methylpyridine (3MP), heavy water, and sodium tetraphenylborate (NaBPh4) solutions by combining results obtained from dynamic light scattering (DLS) and small-angle neutron scattering (SANS). We have addressed three questions: (i) what is the origin of the mesoscale inhomogeneities (order of 100 nm in size) manifested by the "slow mode" in DLS? (ii) Is the periodic structure observed from SANS an inherent property of this system? (iii) What is the universality class of critical behavior in this system? Our results confirm that the "slow mode" observed from DLS experiments corresponds to long-lived, highly stable mesoscale droplets (order of 100 nm in size), which occur only when the solute (3MP) is contaminated by hydrophobic impurities. SANS data confirm the presence of a periodic structure with a periodicity of about 10 nm. This periodic structure cannot be eliminated by nanopore filtration and thus is indeed an inherent solution property. The critical behavior of this system, in the range of concentration and temperatures investigated by DLS experiments, indicates that the criticality belongs to the universality class of the 3-dimensional Ising model.
Minimizing EIT image artefacts from mesh variability in Finite Element Models
Adler, Andy
artefacts which occur in electrical impedance tomography (EIT) images due to limitations in finite element R B Lionheart2 1 Systems and Computer Engineering, Carleton University, Ottawa, Canada 2 School of Mathematics, University of Manchester, UK Abstract. Electrical Impedance Tomography solves an inverse problem
Contrera, G. A. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, 1429 Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Orsaria, M. [CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Gravitation, Astrophysics and Cosmology Group, FCAyG, UNLP, La Plata (Argentina); Scoccola, N. N. [Physics Department, Comision Nacional de Energia Atomica, Av.Libertador 8250, 1429 Buenos Aires (Argentina); CONICET, Rivadavia 1917, 1033 Buenos Aires (Argentina); Universidad Favaloro, Solis 453, 1078 Buenos Aires (Argentina)
2010-09-01T23:59:59.000Z
We study the phase diagram of strongly interacting matter in the framework of a nonlocal SU(2) chiral quark model which includes wave function renormalization and coupling to the Polyakov loop. Both nonlocal interactions based on the frequently used exponential form factor, and on fits to the quark mass and renormalization functions obtained in lattice calculations are considered. Special attention is paid to the determination of the critical points, both in the chiral limit and at finite quark mass. In particular, we study the position of the critical end point as well as the value of the associated critical exponents for different model parametrizations.
Praveen, E., E-mail: svmstaya@gmail.com; Satyanarayana, S. V. M., E-mail: svmstaya@gmail.com [Department of Physics, Pondicherry University, Puducherry-605014 (India)
2014-04-24T23:59:59.000Z
Traditional definition of phase transition involves an infinitely large system in thermodynamic limit. Finite systems such as biological proteins exhibit cooperative behavior similar to phase transitions. We employ recently discovered analysis of inflection points of microcanonical entropy to estimate the transition temperature of the phase transition in q state Potts model on a finite two dimensional square lattice for q=3 (second order) and q=8 (first order). The difference of energy density of states (DOS) ? ln g(E) = ln g(E+ ?E) ?ln g(E) exhibits a point of inflexion at a value corresponding to inverse transition temperature. This feature is common to systems exhibiting both first as well as second order transitions. While the difference of DOS registers a monotonic variation around the point of inflexion for systems exhibiting second order transition, it has an S-shape with a minimum and maximum around the point of inflexion for the case of first order transition.
T Manos; M Robnik
2015-01-21T23:59:59.000Z
We study the quantum kicked rotator in the classically fully chaotic regime $K=10$ and for various values of the quantum parameter $k$ using Izrailev's $N$-dimensional model for various $N \\le 3000$, which in the limit $N \\rightarrow \\infty$ tends to the exact quantized kicked rotator. By numerically calculating the eigenfunctions in the basis of the angular momentum we find that the localization length ${\\cal L}$ for fixed parameter values has a certain distribution, in fact its inverse is Gaussian distributed, in analogy and in connection with the distribution of finite time Lyapunov exponents of Hamilton systems. However, unlike the case of the finite time Lyapunov exponents, this distribution is found to be independent of $N$, and thus survives the limit $N=\\infty$. This is different from the tight-binding model of Anderson localization. The reason is that the finite bandwidth approximation of the underlying Hamilton dynamical system in the Shepelyansky picture (D.L. Shepelyansky, {\\em Phys. Rev. Lett.} {\\bf 56}, 677 (1986)) does not apply rigorously. This observation explains the strong fluctuations in the scaling laws of the kicked rotator, such as e.g. the entropy localization measure as a function of the scaling parameter $\\Lambda={\\cal L}/N$, where $\\cal L$ is the theoretical value of the localization length in the semiclassical approximation. These results call for a more refined theory of the localization length in the quantum kicked rotator and in similar Floquet systems, where we must predict not only the mean value of the inverse of the localization length $\\cal L$ but also its (Gaussian) distribution, in particular the variance. In order to complete our studies we numerically analyze the related behavior of finite time Lyapunov exponents in the standard map and of the 2$\\times$2 transfer matrix formalism. This paper is extending our recent work.
De Castro, Carlos Armando
2011-01-01T23:59:59.000Z
In this paper is developed a simple mathematical model of transient heat transfer under soil with plastic mulch in order to determine with numerical studies the influence of different plastic mulches on the soil temperature and the evolutions of temperatures at different depths with time. The governing differential equations are solved by a Galerkin Finite Element Model, taking into account the nonlinearities due to radiative heat exchange between the soil surface, the plastic mulch and the atmosphere. The model was validated experimentally giving good approximation of the model to the measured data. Simulations were run with the validated model in order to determine the optimal combination of mulch optical properties to maximize the soil temperature with a Taguchi's analysis, proving that the material most used nowadays in Colombia is not the optimal and giving quantitative results of the properties the optimal mulch must possess.
Davidson, Timothy Ross
1994-01-01T23:59:59.000Z
regionally corresponds with the northern limit of the Paleozoic carbonates, at the contact of the Eleana Formation, a Paleozoic aquitard. This study investigates, using finite difference modeling, the relationship between the steep hydraulic gradient...
Lau, Ryan
2007-09-17T23:59:59.000Z
Relatively little is known about marine controlled-source electromagnetic surveys (MCSEM) used to detect hydrocarbon reservoirs. Typical MCSEM require the use of inversion to generate a model of the subsurface. We utilize a 3D finite-element forward...
Yu-Kui Zhou
1995-06-08T23:59:59.000Z
The fused six-vertex models with open boundary conditions are studied. The Bethe ansatz solution given by Sklyanin has been generalized to the transfer matrices of the fused models. We have shown that the eigenvalues of transfer matrices satisfy a group of functional relations, which are the $su$(2) fusion rule held by the transfer matrices of the fused models. The fused transfer matrices form a commuting family and also commute with the quantum group $U_q[sl(2)]$. In the case of the parameter $q^h=-1$ ($h=4,5,\\cdots$) the functional relations in the limit of spectral parameter $u\\to \\i\\infty$ are truncated. This shows that the $su$(2) fusion rule with finite level appears for the six vertex model with the open boundary conditions. We have solved the functional relations to obtain the finite-size corrections of the fused transfer matrices for low-lying excitations. From the corrections the central charges and conformal weights of underlying conformal field theory are extracted. To see different boundary conditions we also have studied the six-vertex model with a twisted boundary condition.
Regueiro, Richard A. (University of Colorado, Boulder, CO); Borja, R. I. (Stanford University, Stanford, CA); Foster, C. D. (Stanford University, Stanford, CA)
2006-10-01T23:59:59.000Z
Localized shear deformation plays an important role in a number of geotechnical and geological processes. Slope failures, the formation and propagation of faults, cracking in concrete dams, and shear fractures in subsiding hydrocarbon reservoirs are examples of important effects of shear localization. Traditional engineering analyses of these phenomena, such as limit equilibrium techniques, make certain assumptions on the shape of the failure surface as well as other simplifications. While these methods may be adequate for the applications for which they were designed, it is difficult to extrapolate the results to more general scenarios. An alternative approach is to use a numerical modeling technique, such as the finite element method, to predict localization. While standard finite elements can model a wide variety of loading situations and geometries quite well, for numerical reasons they have difficulty capturing the softening and anisotropic damage that accompanies localization. By introducing an enhancement to the element in the form of a fracture surface at an arbitrary position and orientation in the element, we can regularize the solution, model the weakening response, and track the relative motion of the surfaces. To properly model the slip along these surfaces, the traction-displacement response must be properly captured. This report focuses on the development of a constitutive model appropriate to localizing geomaterials, and the embedding of this model into the enhanced finite element framework. This modeling covers two distinct phases. The first, usually brief, phase is the weakening response as the material transitions from intact continuum to a body with a cohesionless fractured surface. Once the cohesion has been eliminated, the response along the surface is completely frictional. We have focused on a rate- and state-dependent frictional model that captures stable and unstable slip along the surface. This model is embedded numerically into the element using a generalized trapezoidal formulation. While the focus is on the constitutive model of interest, the framework is also developed for a general surface response. This report summarizes the major research and development accomplishments for the LDRD project titled 'Cohesive Zone Modeling of Failure in Geomaterials: Formulation and Implementation of a Strong Discontinuity Model Incorporating the Effect of Slip Speed on Frictional Resistance'. This project supported a strategic partnership between Sandia National Laboratories and Stanford University by providing funding for the lead author, Craig Foster, during his doctoral research.
Hiroaki Kohyama
2008-04-30T23:59:59.000Z
We construct the phase diagram of the chiral and diquark condensates at finite temperature and density in the 1+1 dimensional (2D) two flavor massless Gross Neveu model. The resultant phase diagram shows (I) the chiral condensed phase at low temperature and density, (II) the diquark condensed phase at low temperature and high density, and (III) the chiral and diquark coexisting phase at low temperature and intermediate density. This phase structure is also seen in the 3D Gross Neveu model and the 4D Nambu Jona-Lasinio (NJL) model. Thus the phase diagrams of the chiral and diquark condensates in the NJL-type models do not change qualitatively in 2D, 3D and 4D.
Energy Landscape of the Finite-Size Mean-field 2-Spin Spherical Model and Topology Trivialization
Dhagash Mehta; Jonathan D. Hauenstein; Matthew Niemerg; Nicholas J. Simm; Daniel A. Stariolo
2014-09-29T23:59:59.000Z
Motivated by the recently observed phenomenon of topology trivialization of potential energy landscapes (PELs) for several statistical mechanics models, we perform a numerical study of the finite size $2$-spin spherical model using both numerical polynomial homotopy continuation and a reformulation via non-hermitian matrices. The continuation approach computes all of the complex stationary points of this model while the matrix approach computes the real stationary points. Using these methods, we compute the average number of stationary points while changing the topology of the PEL as well as the variance. Histograms of these stationary points are presented along with an analysis regarding the complex stationary points. This work connects topology trivialization to two different branches of mathematics: algebraic geometry and catastrophe theory, which is fertile ground for further interdisciplinary research.
Analysis and behavioral modeling of the Finite State Machines of the Xpress Transfer Protocol
Madduri, Venkateswara Rao
1994-01-01T23:59:59.000Z
OF THE 3. 4 SPECIFICATION OF THE XTP FINITE STATE MACHINES . A. XTP Context Manager State Machine B. XTP Output State Machine C. XTP Sync State Machine. D. XTP Rate Control State Machine E. XTP Control-Send State Machine. . . F. XTP Input State... control parameters 26 II XTP context manager state transition table[12]. III XTP output state machine transition table [12]. IV XTP sync state machine transition table[12]. 40 V XTP rate control state machine transition table[12]. VI XTP control...
Modeling and simulation for a PEM fuel cell with catalyst layers in finite thickness.
Yin, Jianghui (Author)
2007-01-01T23:59:59.000Z
??A detailed non-isothermal computational fluid dynamics (CFD) model for proton electrolyte membrane (PEM) fuel cells is developed in this thesis. This model consists of the (more)
Characterization of Caribbean Meso-Scale Eddies Jose M. Lopez
Gilbes, Fernando
Characterization of Caribbean Meso-Scale Eddies Jose M. Lopez Department of Marine Sciences, P-term goal is to improve predictivity of physical, biogeochemical and optical properties of Eastern Caribbean, biological and optical variables across frontal and eddy boundaries in the Eastern Caribbean Sea · To develop
Molecule-Mimetic Chemistry and Mesoscale Self-Assembly
Prentiss, Mara
Molecule-Mimetic Chemistry and Mesoscale Self-Assembly NED B. BOWDEN, MARCUS WECK, INSUNG S. CHOI systems. We suggest that it will be possible to develop complex structures composed of "objects" that self-assemble, shape recognition, and size exclusion can be used to guide the self-assembly of these objects
LANSCE School on Neutron Scattering: Materials at the Mesoscale
1 11th LANSCE School on Neutron Scattering: Materials at the Mesoscale Lujan Center Los Alamos. Please name the applicant for admission to the 11th LANSCE School on Neutron Scattering: Last, First LANSCE School on Neutron Scattering including: drive and motivation, ability to work with others
Goudon, Thierry, E-mail: thierry.goudon@inria.fr [Team COFFEE, INRIA Sophia Antipolis Mediterranee (France) [Team COFFEE, INRIA Sophia Antipolis Mediterranee (France); Labo. J.A. Dieudonne CNRS and Univ. Nice-Sophia Antipolis (UMR 7351), Parc Valrose, 06108 Nice cedex 02 (France); Parisot, Martin, E-mail: martin.parisot@gmail.com [Project-Team SIMPAF, INRIA Lille Nord Europe, Park Plazza, 40 avenue Halley, F-59650 Villeneuve d'Ascq cedex (France)] [Project-Team SIMPAF, INRIA Lille Nord Europe, Park Plazza, 40 avenue Halley, F-59650 Villeneuve d'Ascq cedex (France)
2012-10-15T23:59:59.000Z
In the so-called Spitzer-Haerm regime, equations of plasma physics reduce to a nonlinear parabolic equation for the electronic temperature. Coming back to the derivation of this limiting equation through hydrodynamic regime arguments, one is led to construct a hierarchy of models where the heat fluxes are defined through a non-local relation which can be reinterpreted as well by introducing coupled diffusion equations. We address the question of designing numerical methods to simulate these equations. The basic requirement for the scheme is to be asymptotically consistent with the Spitzer-Haerm regime. Furthermore, the constraints of physically realistic simulations make the use of unstructured meshes unavoidable. We develop a Finite Volume scheme, based on Vertex-Based discretization, which reaches these objectives. We discuss on numerical grounds the efficiency of the method, and the ability of the generalized models in capturing relevant phenomena missed by the asymptotic problem.
Dingle, A.N.
1982-05-12T23:59:59.000Z
A numerical model designed for the study of mesoscale weather phenomena is presented. It is a three-dimensional, time-dependent model based upon a mesoscale primitive-equation system, and it includes parameterizations of cloud and precipitation processes, boundary-layer transfers, and ground surface energy and moisture budgets. This model was used to simulate the lake-effect convergence over and in the lee of Lake Michigan in late fall and early winter. The lake-effect convergence is created in advected cold air as it moves first from cold land to the warm constant-temperature lake surface, and then on to cold land. A numerical experiment with a prevailing northwesterly wind is conducted for a period of twelve hours. Two local maxima of the total precipitation are observed along the eastern shore of Lake Michigan. The results in this hypothetical case correspond quite well to the observed precipitation produced by a real event in which the hypothetical conditions are approximately fulfilled.
Liu, Yueqiang, E-mail: yueqiang.liu@ccfe.ac.uk; Chapman, I. T. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)] [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Graves, J. P. [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association EURATOM-Confederation Suisse, 1015 Lausanne (Switzerland)] [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association EURATOM-Confederation Suisse, 1015 Lausanne (Switzerland); Hao, G. Z. [Southwestern Institute of Physics, PO Box 432, Chengdu 610041 (China)] [Southwestern Institute of Physics, PO Box 432, Chengdu 610041 (China); Wang, Z. R.; Menard, J. E.; Okabayashi, M. [Princeton Plasma Physics Laboratory, Princeton University, PO Box 451, Princeton, New Jersey 08543-0451 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, PO Box 451, Princeton, New Jersey 08543-0451 (United States); Strait, E. J.; Turnbull, A. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)] [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)
2014-05-15T23:59:59.000Z
A non-perturbative magnetohydrodynamic-kinetic hybrid formulation is developed and implemented into the MARS-K code [Liu et al., Phys. Plasmas 15, 112503 (2008)] that takes into account the anisotropy and asymmetry [Graves et al., Nature Commun. 3, 624 (2012)] of the equilibrium distribution of energetic particles (EPs) in particle pitch angle space, as well as first order finite orbit width (FOW) corrections for both passing and trapped EPs. Anisotropic models, which affect both the adiabatic and non-adiabatic drift kinetic energy contributions, are implemented for both neutral beam injection and ion cyclotron resonant heating induced EPs. The first order FOW correction does not contribute to the precessional drift resonance of trapped particles, but generally remains finite for the bounce and transit resonance contributions, as well as for the adiabatic contributions from asymmetrically distributed passing particles. Numerical results for a 9MA steady state ITER plasma suggest that (i) both the anisotropy and FOW effects can be important for the resistive wall mode stability in ITER plasmas; and (ii) the non-perturbative approach predicts less kinetic stabilization of the mode, than the perturbative approach, in the presence of anisotropy and FOW effects for the EPs. The latter may partially be related to the modification of the eigenfunction of the mode by the drift kinetic effects.
Martini, Matus; Gustafson, William I.; Yang, Qing; Xiao, Heng
2014-11-27T23:59:59.000Z
Organized mesoscale cellular convection (MCC) is a common feature of marine stratocumulus that forms in response to a balance between mesoscale dynamics and smaller scale processes such as cloud radiative cooling and microphysics. We use the Weather Research and Forecasting model with chemistry (WRF-Chem) and fully coupled cloud-aerosol interactions to simulate marine low clouds during the VOCALS-REx campaign over the southeast Pacific. A suite of experiments with 3- and 9-km grid spacing indicates resolution-dependent behavior. The simulations with finer grid spacing have smaller liquid water paths and cloud fractions, while cloud tops are higher. The observed diurnal cycle is reasonably well simulated. To isolate organized MCC characteristics we develop a new automated method, which uses a variation of the watershed segmentation technique that combines the detection of cloud boundaries with a test for coincident vertical velocity characteristics. This ensures that the detected cloud fields are dynamically consistent for closed MCC, the most common MCC type over the VOCALS-REx region. We demonstrate that the 3-km simulation is able to reproduce the scaling between horizontal cell size and boundary layer height seen in satellite observations. However, the 9-km simulation is unable to resolve smaller circulations corresponding to shallower boundary layers, instead producing invariant MCC horizontal scale for all simulated boundary layers depths. The results imply that climate models with grid spacing of roughly 3 km or smaller may be needed to properly simulate the MCC structure in the marine stratocumulus regions.
Crossing the mesoscale no-mans land via parallel kinetic Monte Carlo.
Garcia Cardona, Cristina (San Diego State University); Webb, Edmund Blackburn, III; Wagner, Gregory John; Tikare, Veena; Holm, Elizabeth Ann; Plimpton, Steven James; Thompson, Aidan Patrick; Slepoy, Alexander (U. S. Department of Energy, NNSA); Zhou, Xiao Wang; Battaile, Corbett Chandler; Chandross, Michael Evan
2009-10-01T23:59:59.000Z
The kinetic Monte Carlo method and its variants are powerful tools for modeling materials at the mesoscale, meaning at length and time scales in between the atomic and continuum. We have completed a 3 year LDRD project with the goal of developing a parallel kinetic Monte Carlo capability and applying it to materials modeling problems of interest to Sandia. In this report we give an overview of the methods and algorithms developed, and describe our new open-source code called SPPARKS, for Stochastic Parallel PARticle Kinetic Simulator. We also highlight the development of several Monte Carlo models in SPPARKS for specific materials modeling applications, including grain growth, bubble formation, diffusion in nanoporous materials, defect formation in erbium hydrides, and surface growth and evolution.
TXLINE-2: a finite length model to simulate the dispersion of pollutants from roadways
Schroeder, James Henry
2012-06-07T23:59:59.000Z
Modelling Near Roadways Gradient Transport Approach B. Existing Dispersion Models HIWAY-2 CALINE-3 TXLINE C. Methods of Deteimining Source Strl ngth 12 O. Methods of Testing and Compar1ng Models ties s Balance Tea t Comparison to Data l4 E. Data... Dispersion From Roadways E. Link Capabilities F. Comparison of Dispets1 on Mocieis Using Existing Data 72 Comparison to the GM Data 72 Comparison to the Texas Data 75 Comparison to the SRI Data General Discussion 90 CHAPTER V TABLE OF CONTENTS...
Arslan, Melis
2005-01-01T23:59:59.000Z
Many biological, natural and synthetic materials possess a networked or micro-truss-like microstructure. In this thesis work, a general microstructurally-informed continuum level constitutive model of the large stretch ...
A multi-scale iterative approach for finite element modeling of thermal contact resistance
Thompson, Mary Kathryn, 1980-
2007-01-01T23:59:59.000Z
Surface topography has long been considered a key factor in the performance of many contact applications including thermal contact resistance. However, essentially all analytical and numerical models of thermal contact ...
Smart finite state devices: A modeling framework for demand response technologies
Turitsyn, Konstantin
We introduce and analyze Markov Decision Process (MDP) machines to model individual devices which are expected to participate in future demand-response markets on distribution grids. We differentiate devices into the ...
An elastic-perfectly plastic flow model for finite element analysis of perforated materials
Jones, D.P.; Gordon, J.L.; Hutula, D.N.; Banas, D.; Newman, J.B.
1999-02-01T23:59:59.000Z
This paper describes the formulation of an elastic-perfectly plastic flow theory applicable to equivalent solid [EQS] modeling of perforated materials. An equilateral triangular array of circular penetrations is considered. The usual assumptions regarding geometry and loading conditions applicable to the development of elastic constants for EQS modeling of perforated plates are considered to apply here. An elastic-perfectly plastic [EPP] EQS model is developed for a collapse surface that includes fourth-order stress terms. The fourth order yield function has been shown to be appropriate for plates with a triangular array of circular holes. A complete flow model is formulated using the consistent tangent modulus approach based on the fourth order yield function.
Mongkolcheep, Kathira
2010-10-12T23:59:59.000Z
The purpose of this work is to present a methodology to predict vibrations of drilllstrings for oil recovery service. The work extends a previous model of the drill collar between two stabilizers in the literature to include drill collar flexibility...
k - Version of Finite Element Method for Polymer flows using Giesekus Constitutive Model
Deshpande, Kedar M.
2008-01-31T23:59:59.000Z
and hence high Deborah number flows are invariably associated with higher flow rates and thus higher velocities. In many standard model problems such as couette flow, lid driven cavity, expansion, contraction etc, severe deborah number (De) limitations...
A finite element model of the turbulent flow field in a centrifugal impeller
Hlavaty, Steven Todd
1993-01-01T23:59:59.000Z
, or for applications such as pumps utilizing a liquid as the working medium. Full ellipticity of the flow- governing equations throughout the computational domain is rigorously retained. As a result, the model is conceptually capable of predicting real-flow effects... such as flow separation and recirculation, regardless of whether such complex flow behavior is local or massive. Applicability of the model is illustrated using a typical pump impeller of the purely centrifugal type. In presenting the computed flow field...
Convective cell development and propagation in a mesoscale convective complex
Ahn, Yoo-Shin
2012-06-07T23:59:59.000Z
~ , National Fisheries University of Pusan Chairman of Advisory Committee: Dr ~ Kennth CD Brundidge A case study was made of the mesoscale convective complex (MCC) which occurred over southern Oklahoma and northern Texas on 27 May 1981. This storm moved... in an east-southeasterly direction and during much of its lifetime was observable by radars at Oklahoma City, OK and Stephenville, TX. It was found that the direction of cell (VIP level 3 or more reflectivity) propagation was somewhat erratic...
Styles, Vanessa
FOR SUPERCONDUCTIVITY C.M. ELLIOTT, D. KAY #3; AND V.STYLES y CENTRE FOR MATHEMATICAL ANALYSIS AND ITS APPLICATIONS long cylindrical superconductor subject to a transverse magnetic #12;eld. We prove an error between of an evolutionary variational inequality arising from a critical state model for a type-II superconductor
Finite element and nite volume discretizations of Drift-Di usion type uid models for semiconductors
Brezzi, Franco
Milano Via Bonardi 9, 20133 Milano, Italy z University of Western Australia Department of Mathematics and Statistics Nedlands, Western Australia 6907, Australia This paper is to appear as a Chapter of Numerical the initial/boundary conditions which complete the model. We also consider in more detail the Energy
Optimization of relativistic mean field model for finite nuclei to neutron star matter
B. K. Agrawal; A. Sulaksono; P. -G. Reinhard
2012-04-12T23:59:59.000Z
We have optimized the parameters of extended relativistic mean-field model using a selected set of global observables which includes binding energies and charge radii for nuclei along several isotopic and isotonic chains and the iso-scalar giant monopole resonance energies for the $^{90}$Zr and $^{208}$Pb nuclei. The model parameters are further constrained by the available informations on the energy per neutron for the dilute neutron matter and bounds on the equations of state of the symmetric and asymmetric nuclear matter at supra-nuclear densities. Two new parameter sets BSP and IUFSU* are obtained, later one being the variant of recently proposed IUFSU parameter set. The BSP parametrization uses the contributions from the quartic order cross-coupling between $\\omega$ and $\\sigma$ mesons to model the high density behaviour of the equation of state instead of the $\\omega$ meson self-coupling as in the case of IUFSU* or IUFSU. Our parameter sets yield appreciable improvements in the binding energy systematics and the equation of state for the dilute neutron matter. The importance of the quartic order $\\omega-\\sigma$ cross coupling term of the extended RMF model, as often ignored, is realized.
E-Print Network 3.0 - approximate mesoscale information Sample...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of Technology Collection: Engineering 5 Mesoscale variability in time series data: Satellite-based estimates for the U.S. JGOFS Bermuda Atlantic Summary: coverage. GLOVER ET...
Finite Element Modeling of Suspended Particle Migration in Non-Newtonian Fluids
Altobelli, S.; Baer, T.; Mondy, L.; Rao, R.; Stephens, T.
1999-03-04T23:59:59.000Z
Shear-induced migration of particles is studied during the slow flow of suspensions of spheres (particle volume fraction {phi} = 0.50) in an inelastic but shear-thinning, suspending fluid in flow between counterrotating concentric cylinders, The conditions are such that nonhydrodynamic effects are negligible. The movement of particles away from the high shear rate region is more pronounced than in a Newtonian suspending liquid. We test a continuum constitutive model for the evolution of particle concentration in a flowing suspension proposed by Phillips et al. (1992) by using shear-thinning, suspending fluids. The fluid constitutive equation is Carreau-like in its shear-thinning behavior but also varies with the local particle concentration. The model is compared with the experimental data gathered with nuclear magnetic resonance (NMR) imaging.
Smart Finite State Devices: A Modeling Framework for Demand Response Technologies
Turitsyn, Konstantin; Ananyev, Maxim; Chertkov, Michael
2011-01-01T23:59:59.000Z
We introduce and analyze Markov Decision Process (MDP) machines to model individual devices which are expected to participate in future demand-response markets on distribution grids. We differentiate devices into the following four types: (a) optional loads that can be shed, e.g. light dimming; (b) deferrable loads that can be delayed, e.g. dishwashers; (c) controllable loads with inertia, e.g. thermostatically-controlled loads, whose task is to maintain an auxiliary characteristic (temperature) within pre-defined margins; and (d) storage devices that can alternate between charging and generating. Our analysis of the devices seeks to find their optimal price-taking control strategy under a given stochastic model of the distribution market.
Pettit, J. R. [Rolls-Royce Nuclear, PO BOX 2000, Derby, UK, DE21 7XX and Research Centre for NDE, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Walker, A. [Rolls-Royce Nuclear, PO BOX 2000, Derby DE21 7XX (United Kingdom); Lowe, M. J. S. [Research Centre for NDE, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)
2014-02-18T23:59:59.000Z
Defects which posses rough surfaces greatly affect ultrasonic wave scattering behaviour, often reducing the magnitude of reflected signals. Ultrasonic inspections rely upon this response for detecting and sizing flaws. For safety critical components reliable characterisation is crucial. Therefore, providing an accurate means to predict reductions in signal amplitude is essential. An extension of Kirchhoff theory has formed the basis for the UK power industry inspection justifications. However, it is widely recognised that these predictions are pessimistic owing to analytical approximations. A numerical full field modelling approach does not fall victim to such limitations. Here, a Finite Element model is used to aid in setting a non-conservative reporting threshold during the inspection of a large pressure vessel forging that might contain embedded rough defects. The ultrasonic response from multiple rough surfaces defined by the same statistical class is calculated for normal incident compression waves. The approach is validated by comparing coherent scattering with predictions made by Kirchhoff theory. At lower levels of roughness excellent agreement is observed, whilst higher values confirm the pessimism of Kirchhoff theory. Furthermore, the mean amplitude in the specular direction is calculated. This represents the information obtained during an inspection, indicating that reductions due to increasing roughness are significantly less than the coherent component currently being used.
Antoine, Xavier - Institut de Mathématiques ?lie Cartan, Université Henri Poincaré
Accepted 12 January 2009 Available online 21 January 2009 Keywords: Helmholtz equation Acoustic scattering Short-wave problem Finite element method Pollution Accuracy On-Surface Radiation Condition method a b- lems in view of a numerical finite element solution. It is well-known that pollution error causes
Vortex arrays and meso-scale turbulence of self-propelled particles
Robert Grossmann; Pawel Romanczuk; Markus Br; Lutz Schimansky-Geier
2014-05-30T23:59:59.000Z
Inspired by the Turing mechanism for pattern formation, we propose a simple self-propelled particle model with short-ranged alignment and anti-alignment at larger distances. It is able to produce orientationally ordered states, periodic vortex patterns as well as meso-scale turbulence. The latter phase resembles observations in dense bacterial suspensions. The model allows a systematic derivation and analysis of a kinetic theory as well as hydrodynamic equations for density and momentum fields. A phase diagram with regions of such pattern formation as well as spatially homogeneous orientational order and disorder is obtained from a linear stability analysis of these continuum equations. Microscopic Langevin simulations of the self-propelled particle system are in agreement with these findings.
Pion condensation in the two--flavor chiral quark model at finite baryochemical potential
T. Herpay; P. Kovcs
2008-11-17T23:59:59.000Z
Pion condensation is studied at one--loop level and nonzero baryochemical potential in the framework of two flavor constituent quark model using the one--loop level optimized perturbation theory for the resummation of the perturbative series. A Landau type of analysis is presented for the investigation of the phase boundary between the pion condensed/non-condensed phases. The statement that the condensation starts at $\\muI = m_{\\pi}$ is slightly modified by one--loop corrections. The second order critical surface is determined and analysed in the $\\muI-\\muB-T$ space. The $\\muI$ dependence of the one--loop level charged pion pole masses is also studied.
James, Stephen M.
2011-08-08T23:59:59.000Z
-dimensional axisymmetric beam-element code. ANSYS is used as a code to build three-dimensional non-axisymmetric solid-element casing models. The work done in this thesis opens the scope to incorporate complex non-axisymmetric casing models with XLTRC2....
Finite Element Modelling of the Sawing of DC Cast AA2024 Aluminium Alloy Slabs
Drezet, J.-M. [Computational Materials Laboratory, School of Engineering, Ecole Polytechnique Federale de Lausanne, Station 12, CH-1015 Lausanne (Switzerland); Ludwig, O. [Calcom-ESI SA, PSE-A, CH-1015 Lausanne (Switzerland); Heinrich, B. [Alcan Aluminium Valais SA, CH3960 Sierre (Switzerland)
2007-04-07T23:59:59.000Z
In the semi-continuous casting of large cross-section rolling sheet ingots of high-strength aluminum alloys (2xxx and 7xxx series), the control of the residual (internal) stresses generated by the non-uniform cooling becomes a necessity. These stresses must be relieved by a thermal treatment before the head and foot of the ingot can be cut. Otherwise, the saw can be caught owing to compressive stresses or cut parts may be ejected thus injuring people or damaging equipment. These high added-value ingots need to be produced in secure conditions. Moreover, a better control of the sawing procedure could allow the suppression of the thermal treatment and therefore save time and energy. By studying the stress build-up during casting and the stress relief during sawing, key parameters for the control and optimization of the processing steps, can be derived. To do so, the direct chill (DC) casting of the AA2024 alloy is modeled with ABAQUS 6.5 with special attention to the thermo-mechanical properties of the alloy. The sawing operation is then simulated by removing mesh elements so as to reproduce the progression of the saw in the ingot. Preliminary results showing the stress relief during sawing accompanied by the risk of saw blocking due to compression or initiating a crack ahead of the saw, are analyzed with an approach based on the rate of strain energy release.
Boundary Conditions of the Hydro-Cascade Model and Relativistic Kinetic Equations for Finite Domains
K. A. Bugaev
2004-01-29T23:59:59.000Z
A detailed analysis of the coupled relativistic kinetic equations for two domains separated by a hypersurface having both space- and time-like parts is presented. Integrating the derived set of transport equations, we obtain the correct system of the hydro+cascade equations to model the relativistic nuclear collision process. Remarkably, the conservation laws on the boundary between domains conserve separately both the incoming and outgoing components of energy, momentum and baryonic charge. Thus, the relativistic kinetic theory generates twice the number of conservation laws compared to traditional hydrodynamics. Our analysis shows that these boundary conditions between domains, the three flux discontinuity, can be satisfied only by a special superposition of two cut-off distribution functions for the ``out'' domain. All these results are applied to the case of the phase transition between quark gluon plasma and hadronic matter. The possible consequences for an improved hydro+cascade description of the relativistic nuclear collisions are discussed. The unique properties of the three flux discontinuity and their effect on the space-time evolution of the transverse expansion are also analyzed. The possible modifications of both transversal radii from pion correlations generated by a correct hydro+cascade approach are discussed.
Lo, F. S.; Lee, T. H. [Department of Mechanical Engineering, National Central University, Jhongli City, Taoyuan County 32001, Taiwan (China)] [Department of Mechanical Engineering, National Central University, Jhongli City, Taoyuan County 32001, Taiwan (China); Lu, P. S. [NanoScience Simulation Laboratory, Fu Jen Catholic University, Xinzhuang Dist., New Taipei City 24205, Taiwan (China)] [NanoScience Simulation Laboratory, Fu Jen Catholic University, Xinzhuang Dist., New Taipei City 24205, Taiwan (China); Ragan-Kelley, B. [Applied Science and Technology, University of California, Berkeley, California 94720 (United States) [Applied Science and Technology, University of California, Berkeley, California 94720 (United States); Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States); Minnich, A. [Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States) [Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States); Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125 (United States); Lin, M. C., E-mail: mingchiehlin@gmail.com [NanoScience Simulation Laboratory, Fu Jen Catholic University, Xinzhuang Dist., New Taipei City 24205, Taiwan (China); Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States); Verboncoeur, J. P. [Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States) [Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (United States); Department of Electrical and Computing Engineering, Michigan State University, East Lansing, Michigan 48824 (United States)
2014-02-15T23:59:59.000Z
A thermionic energy converter (TEC) is a static device that converts heat directly into electricity by boiling electrons off a hot emitter surface across a small inter-electrode gap to a cooler collector surface. The main challenge in TECs is overcoming the space charge limit, which limits the current transmitted across a gap of a given voltage and width. We have verified the feasibility of studying and developing a TEC using a bounded finite-difference time-domain particle-in-cell plasma simulation code, OOPD1, developed by Plasma Theory and Simulation Group, formerly at UC Berkeley and now at Michigan State University. In this preliminary work, a TEC has been modeled kinetically using OOPD1, and the accuracy has been verified by comparing with an analytically solvable case, giving good agreement. With further improvement of the code, one will be able to quickly and cheaply analyze space charge effects, and seek designs that mitigate the space charge effect, allowing TECs to become more efficient and cost-effective.
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 ...
Prentiss, Mara
Mesoscale Self-Assembly of Hexagonal Plates Using Lateral Capillary Forces: Synthesis Using examines self-assembly in a quasi-two-dimensional, mesoscale system. The system studied here involves and hydrophilic faces on the hexagonal plates led to three outcomes: (i) the extension of the strategies of self-assembly
Generation of strong mesoscale eddies by weak ocean gyres by Michael A. Spall1
Generation of strong mesoscale eddies by weak ocean gyres by Michael A. Spall1 ABSTRACT The generation of strong mesoscale variability through instability of the large-scale circulation in the interior of oceanic gyres is addressed. While previous studies have shown that eddies generated from weakly sheared
Customizing mesoscale self-assembly with 3D printing
M. Poty; G. Lumay; N. Vandewalle
2013-10-17T23:59:59.000Z
Self-assembly due to capillary forces is a common method for generating 2D mesoscale structures from identical floating particles at the liquid-air interface. Designing building blocks to obtain a desired mesoscopic structure is a scientific challenge. We show herein that it is possible to shape the particles with a low cost 3D printer, for composing specific mesoscopic structures. Our method is based on the creation of capillary multipoles inducing either attractive or repulsive forces. Since capillary interactions can be downscaled, our method opens new ways to low cost microfabrication.
Poster Sessions J. Dudhia Mesoscale and Microscale Meteorology Division
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - September 2006PhotovoltaicSeptember 22, 2014SocietyJ. Dudhia Mesoscale and
Deterministic, Nanoscale Fabrication of Mesoscale Objects
Jr., R M; Shirk, M; Gilmer, G; Rubenchik, A
2004-09-24T23:59:59.000Z
Neither LLNL nor any other organization has the capability to perform deterministic fabrication of mm-sized objects with arbitrary, {micro}m-sized, 3-dimensional features with 20-nm-scale accuracy and smoothness. This is particularly true for materials such as high explosives and low-density aerogels. For deterministic fabrication of high energy-density physics (HEDP) targets, it will be necessary both to fabricate features in a wide variety of materials as well as to understand and simulate the fabrication process. We continue to investigate, both in experiment and in modeling, the ablation/surface-modification processes that occur with the use of laser pulses that are near the ablation threshold fluence. During the first two years, we studied ablation of metals, and we used sub-ps laser pulses, because pulses shorter than the electron-phonon relaxation time offered the most precise control of the energy that can be deposited into a metal surface. The use of sub-ps laser pulses also allowed a decoupling of the energy-deposition process from the ensuing movement/ablation of the atoms from the solid, which simplified the modeling. We investigated the ablation of material from copper, gold, and nickel substrates. We combined the power of the 1-D hydrocode ''HYADES'' with the state-of-the-art, 3-D molecular dynamics simulations ''MDCASK'' in our studies. For FY04, we have stretched ourselves to investigate laser ablation of carbon, including chemically-assisted processes. We undertook this research, because the energy deposition that is required to perform direct sublimation of carbon is much higher than that to stimulate the reaction 2C + O{sub 2} => 2CO. Thus, extremely fragile carbon aerogels might survive the chemically-assisted process more readily than ablation via direct laser sublimation. We had planned to start by studying vitreous carbon and move onto carbon aerogels. We were able to obtain flat, high-quality vitreous carbon, which was easy to work on, experimentally and relatively easy to model. We were provided with bulk samples of carbon aerogel by Dr. Joe Satcher, but the shop that would have prepared mounted samples for us was overwhelmed by programmatic assignments. We are pursuing aligned carbon nanotubes, provided to us by colleagues at NASA Ames Research Center, as an alternative to aerogels. Dr. Gilmer started modeling the laser/thermally accelerated reactions of carbon with H{sub 2}, rather than O{sub 2}, due to limited information on equation of state for CO. We have extended our molecular dynamics models of ablation to include carbon in the form of graphite, vitreous carbon, and aerogels. The computer code has features that allow control of temperature, absorption of shock waves, and for the ejection of material from the computational cell. We form vitreous carbon atomic configurations by melting graphite in a microcanonical cell at a temperature of about 5000K. Quenching the molten carbon at a controlled rate of cooling yields material with a structure close to that of the vitreous carbon produced in the laboratory. To represent the aerogel, we have a computer code that connects ''graphite'' rods to randomly placed points in the 3-D computational cell. Ablation simulations yield results for vitreous carbon similar to our previous results with copper, usually involving the transient melting of the material above the threshold energy density. However, some fracturing in the solid regions occurs in this case, but was never observed in copper. These simulations are continuing, together with studies of the reaction of hydrogen with vitreous graphite at high temperatures. These reactions are qualitatively similar to that of oxygen with the carbon atoms at the surface, and the simulations should provide insight into the applicability of the use of chemical reactions to shape the surfaces of aerogels.
Langerman, M.A.
1990-09-01T23:59:59.000Z
Steady-state modeling considerations for simulating the in situ vitrification (ISV) process are documented based upon the finite element numerical approach. Recommendations regarding boundary condition specifications and mesh discretization are presented. The effects of several parameters on the ISV process response are calculated and the results discussed. The parameters investigated include: (1) electrode depth, (2) ambient temperature, (3) supplied current, (4) electrical conductivity, (5) electrode separation, and (6) soil/waste characterization. 13 refs., 29 figs., 1 tab.
Introduction Positive finite rank . . .
Li, Chi-Kwong
Introduction Positive finite rank . . . Positive finite rank . . . Positive finite rank . . . ¯? I qixf1981@sxu.edu.cn #12;Introduction Positive finite rank . . . Positive finite rank . . . Positive finite rank . . . ¯? I K 12 19 £ ¶w« ' 4 ò ? 1 Introduction · In quantum mechanics, a quantum system
Analysis of Mesoscale Model Data for Wind Integration (Poster)
Schwartz, M.; Elliott, D.; Lew, D.; Corbus, D.; Scott, G.; Haymes, S.; Wan, Y. H.
2009-05-01T23:59:59.000Z
Supports examination of implications of national 20% wind vision, and provides input to integration and transmission studies for operational impact of large penetrations of wind on the grid.
AN URBAN SURFACE EXCHANGE PARAMETERISATION FOR MESOSCALE MODELS
boundary layer, Urban climato- logy, Urban energy balance. 1. Introduction The main reason floor) and vertical (walls) surfaces on the wind speed, temperature and turbulent kinetic energy in a bidimensional case of a city over flat terrain. The new parameterisation is shown to be able to reproduce
J. McCarty; A. J. Clark; J. Copperman; M. G. Guenza
2014-07-03T23:59:59.000Z
Structural and thermodynamic consistency of coarse-graining models across multiple length scales is essential for the predictive role of multi-scale modeling and molecular dynamic simulations that use mesoscale descriptions. Our approach is a coarse-grained model based on integral equation theory, which can represent polymer chains at variable levels of chemical details. The model is analytical and depends on molecular and thermodynamic parameters of the system under study, as well as on the direct correlation function in the k --> 0 limit, c0. A numerical solution to the PRISM integral equations is used to determine c0, by adjusting the value of the effective hard sphere diameter, d, to agree with the predicted equation of state. This single quantity parameterizes the coarse-grained potential, which is used to perform mesoscale simulations that are directly compared with atomistic-level simulations of the same system. We test our coarse-graining formalism by comparing structural correlations, isothermal compressibility, equation of state, Helmholtz and Gibbs free energies, and potential energy and entropy using both united atom and coarse-grained descriptions. We find quantitative agreement between the analytical formalism for the thermodynamic properties, and the results of Molecular Dynamics simulations, independent of the chosen level of representation. In the mesoscale description, the potential energy of the soft-particle interaction becomes a free energy in the coarse-grained coordinates which preserves the excess free energy from an ideal gas across all levels of description. The structural consistency between the united-atom and mesoscale descriptions means the relative entropy between descriptions has been minimized without any variational optimization parameters. The approach is general and applicable to any polymeric system in different thermodynamic conditions.
McCarty, J.; Clark, A. J.; Copperman, J.; Guenza, M. G., E-mail: mguenza@uoregon.edu [Department of Chemistry and Biochemistry, and Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403 (United States)
2014-05-28T23:59:59.000Z
Structural and thermodynamic consistency of coarse-graining models across multiple length scales is essential for the predictive role of multi-scale modeling and molecular dynamic simulations that use mesoscale descriptions. Our approach is a coarse-grained model based on integral equation theory, which can represent polymer chains at variable levels of chemical details. The model is analytical and depends on molecular and thermodynamic parameters of the system under study, as well as on the direct correlation function in the k ? 0 limit, c{sub 0}. A numerical solution to the PRISM integral equations is used to determine c{sub 0}, by adjusting the value of the effective hard sphere diameter, d{sub HS}, to agree with the predicted equation of state. This single quantity parameterizes the coarse-grained potential, which is used to perform mesoscale simulations that are directly compared with atomistic-level simulations of the same system. We test our coarse-graining formalism by comparing structural correlations, isothermal compressibility, equation of state, Helmholtz and Gibbs free energies, and potential energy and entropy using both united atom and coarse-grained descriptions. We find quantitative agreement between the analytical formalism for the thermodynamic properties, and the results of Molecular Dynamics simulations, independent of the chosen level of representation. In the mesoscale description, the potential energy of the soft-particle interaction becomes a free energy in the coarse-grained coordinates which preserves the excess free energy from an ideal gas across all levels of description. The structural consistency between the united-atom and mesoscale descriptions means the relative entropy between descriptions has been minimized without any variational optimization parameters. The approach is general and applicable to any polymeric system in different thermodynamic conditions.
Irbäck, Anders
at finite temperature Anders Irba¨cka) and Frank Potthastb) Department of Theoretical Physics, University. We find that by these algorithms one gains large factors in efficiency in comparison to a fairly well-defined shape. This phase is interesting from the viewpoint of proteins, but for a generic
Probabilistic finite element analysis of marine risers
Leder, H. Vern
1990-01-01T23:59:59.000Z
Review 1. 2 Research Study 10 2 FORMULATION OF THE SECOND ? MOMENT ANALYSIS METHOD 13 2. 1 Finite Element Equations 2. 2 Random Vector Formulation 2. 3 The Correlation Function 2. 4 Random Field Discretization 2. 5 Taylor Series Expansion 2. 6... ILLUSTRATIVE EXAMPLE. . . . . . . . . . . . . . . . . . 4 APPLICATION OF PROBABILISTIC FINITE ELEMENT METHODS TO MARINE RISER ANALYSES 4. 1 Finite Element Model . 4. 1. 1 Formulation of the Equation of Motion 4. 1. 2 Finite Element Discretization 4. 1. 3...
Simulations of amphiphilic fluids using mesoscale lattice-Boltzmann and lattice-gas methods
P. J. Love; M. Nekovee; J. Chin; N. Gonzalez-Segredo; P. V. Coveney
2002-12-06T23:59:59.000Z
We compare two recently developed mesoscale models of binary immiscible and ternary amphiphilic fluids. We describe and compare the algorithms in detail and discuss their stability properties. The simulation results for the cases of self-assembly of ternary droplet phases and binary water-amphiphile sponge phases are compared and discussed. Both models require parallel implementation and deployment on large scale parallel computing resources in order to achieve reasonable simulation times for three-dimensional models. The parallelisation strategies and performance on two distinct parallel architectures are compared and discussed. Large scale three dimensional simulations of multiphase fluids requires the extensive use of high performance visualisation techniques in order to enable the large quantities of complex data to be interpreted. We report on our experiences with two commercial visualisation products: AVS and VTK. We also discuss the application and use of novel computational steering techniques for the more efficient utilisation of high performance computing resources. We close the paper with some suggestions for the future development of both models.
Application of the 85 GHz ice scattering signature to a global study of mesoscale convective systems
Devlin, Karen Irene
1995-01-01T23:59:59.000Z
It has long been observed that tropical convection tends to cluster, organizing into multicellular mesoscale convective systems (MCS), In convective towers, updrafts on the order of 10 m s-I favor the formation of large, precipitation-sized ice...
Mesoscale Origin of the Enhanced Cycling-Stability of the Si...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Mesoscale Origin of the Enhanced Cycling-Stability of the Si-Conductive Polymer Anode for Li-ion Batteries. Abstract: Electrode used in lithium-ion battery is invariably a...
Design of a high-speed, meso-scale nanopositioners driven by electromagnetic actuators
Golda, Dariusz, 1979-
2008-01-01T23:59:59.000Z
The purpose of this thesis is to generate the design and fabrication knowledge that is required to engineer high-speed, six-axis, meso-scale nanopositioners that are driven by electromagnetic actuators. When compared to ...
electroseismic monitoring of co2 sequestration: a finite element ...
Fabio Zyserman
Keywords: Electroseismic Modeling, Poroelasticity, CO2 sequestration, Finite element methods. 2000 AMS ... carbon dioxide emissisons into the atmosphere.
Manufacturing Ultra-Precision Meso-scale Products by Coining
Seugling, R M; Davis, P J; Rickens, K; Osmer, J; Brinksmeier, E
2010-02-18T23:59:59.000Z
A method for replicating ultra-precision, meso-scale features onto a near-net-shape metallic blank has been demonstrated. The 'coining' technology can be used to imprint a wide range of features and/or profiles into two opposing surfaces. The instrumented system provides the ability to measure and control the product thickness and total thickness variation (TTV). The coining mechanism relies on kinematic principles to accurately and efficiently produce ultra-precision work pieces without the production of by products such as machining chips, or grinding swarf while preserving surface finish, material structure and overall form. Coining has been developed as a niche process for manufacturing difficult to machine, millimeter size components made from materials that may present hazardous conditions. In the case described in this paper a refractory metal part, tantalum (Ta) was produced with 4 {micro}m peak to valley 50 {micro}m special wavelength sine wave coined into the surface of 50 {micro}m blank. This technique shows promise for use on ductile materials that cannot be precision machined with conventional single crystal diamond tooling and/or has strict requirements on subsurface damage, surface impurities and grain structure. As a production process, it can be used to reduce manufacturing costs where large numbers of ultra-precision, repetitive designs are required and produce parts out of hazardous materials without generating added waste.
MICRO-SEISMOMETERS VIA ADVANCED MESO-SCALE FABRICATION
Garcia, Caesar A; Onaran, Guclu; Avenson, Brad; Hall, Neal
2014-11-07T23:59:59.000Z
The Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) seek revolutionary sensing innovations for the monitoring of nuclear detonations. Performance specifications are to be consistent with those obtainable by only an elite few products available today, but with orders of magnitude reduction in size, weight, power, and cost. The proposed commercial innovation calls upon several technologies including the combination of meso-scale fabrication and assembly, photonics-based displacement / motion detection methods, and the use of digital control electronics . Early Phase II development has demonstrated verified and repeatable sub 2ng noise floor from 3Hz to 100Hz, compact integration of 3-axis prototypes, and robust deployment exercises. Ongoing developments are focusing on low frequency challenges, low power consumption, ultra-miniature size, and low cross axis sensitivity. We are also addressing the rigorous set of specifications required for repeatable and reliable long-term explosion monitoring, including thermal stability, reduced recovery time from mass re-centering and large mechanical shocks, sensitivity stability, and transportability. Successful implementation will result in small, hand-held demonstration units with the ability to address national security needs of the DOE/NNSA. Additional applications envisioned include military/defense, scientific instrumentation, oil and gas exploration, inertial navigation, and civil infrastructure monitoring.
Koteras, J.R.
1993-07-01T23:59:59.000Z
Tunnels buried deep within the earth constitute an important class geomechanics problems. Two numerical techniques used for the analysis of geomechanics problems, the finite element method and the boundary element method, have complementary characteristics for applications to problems of this type. The usefulness of combining these two methods for use as a geomechanics analysis tool has been recognized for some time, and a number of coupling techniques have been proposed. However, not all of them lend themselves to efficient computational implementations for large-scale problems. This report examines a coupling technique that can form the basis for an efficient analysis tool for large scale geomechanics problems through the use of an iterative equation solver.
Regueiro, Richard A.
, hydrofracturing, or oil shale production. Current macro- scale and multiscale models do not account simultaneously
Smith, Richard Edwin
1992-01-01T23:59:59.000Z
-dimensionalized numerical and analytical solutions of the one-dimensional model using identical parameters to solve Equation 3 when KH is homogeneous. . . . . . . . . . . , , , . . . . . . . . . . . , . . . . . . . . . . . , . , 36 12 Total pore pressure at the end... deposition) for the one-dimensional model. . 40 14 Total pore pressure at the end of Stage 3 (thrust loading) for the one- dimensional model. . 42 15 Decay of X with time beginning at the end of Stage 3 (thrust loading) for the one-dimensional model...
Mesoscale Tank Experiments for Investigating Carbon Tetrachloride Biodegradation
Brady D. Lee; Robert J. Lenhard
2005-06-01T23:59:59.000Z
Mesoscale tank experiments were performed to simulate bioremediation of saturated zone carbon tetrachloride (CCl4) originating from a vadose zone carbon tetrachloride source. The mesoscale tank is 2-m wide by 2-m high by 3-m long and was constructed of stainless steel, yielding a total volume of 12 m3. Simulated geology within the tank consisted of two unconsolidated sand layers separated by a clay layer containing variable-sized stainless steel tubes that represented fractures within a consolidated porous medium. The thickness of the upper sand layer was approximately 55 cm, the thickness of the virtual fracture layer was 25 cm, and the thickness of the lower sand layer was approximately 98 cm. The water table was located at an elevation of approximately 54 cm from the bottom of the tank. CCl4 was added to the sealed tank by pouring 500 ml of neat CCl4 into a beaker buried approximately 10 cm below the upper sand surface through a stainless steel tube. The CCl4 was then allowed to partition through the reactor over time, eventually coming to equilibrium. Once CCl4 equilibrium had occurred in the saturated zone (~500 ppb); the reactor was bioaugmented with a CCl4 degrading culture enriched from the Subsurface Disposal Area at the INEEL. The culture was grown to a cell density of ~ 1.0 x 108 cells/ml and injected into the simulated aquifer through a center sampling port. Following injection of the culture, an initial aliquot of lactate (1,000 g/L), nitrogen, and phosphorus were added to the reactor. Lactate was injected every 3 5 days for one month. After 1 month of operation, a continuous supply of lactate (1,000 g/L) was pumped into the reactor at an average rate of 50 mL/min. CCl4 concentrations in the unsaturated zone were measured using hollow fiber membrane samplers, while liquid samples were analyzed to monitor levels in the simulated aquifer zone. Samples were also taken for analysis of volatile organic acids and cell density. As would be expected, increases in cell density over the length of the cell correlated with the flow of the water through the cell. One week following injection microbes and lactate, cell numbers were in the range of 5.0 x 106 cells/mL, by the end of the experiment cell numbers had increased to approximately 1.94 x 107 cells/mL. Five days after lactate injection was initiated, chloroform appeared in liquid samples taken for chlorinated VOC analysis. CCl4 concentrations in the liquid phase dropped to approximately 180 ppb. At the conclusion of the batch lactate injection phase of the bioaugmentation, CCl4 levels averaged 40 ppb and chloroform levels averaged 44 ppb. Interestingly, once continuous lactate addition was initiated, CCl4 concentrations in the saturated zone increased with spikes as high as 3,000 ppb. Chloroform concentrations also increased following continuous addition of lactate. Since the CCl4 source in the breaker had been depleted, vadose zone concentrations of CCl4 dropped steadily during addition of lactate to the saturated zone. CCl4 levels of ~ 800 ppmv were noted at the beginning of the experiment, levels decreased to below 200 ppmv by the end of the bioaugmentation phase. No chloroform was noted in the vadose zone during testing.
Verley, Jason C.; Axness, Carl L.; Hembree, Charles Edward; Keiter, Eric Richard; Kerr, Bert (New Mexico Institute of Mining and Technology, Socorro, NM)
2012-04-01T23:59:59.000Z
Photocurrent generated by ionizing radiation represents a threat to microelectronics in radiation environments. Circuit simulation tools such as SPICE [1] can be used to analyze these threats, and typically rely on compact models for individual electrical components such as transistors and diodes. Compact models consist of a handful of differential and/or algebraic equations, and are derived by making simplifying assumptions to any of the many semiconductor transport equations. Historically, many photocurrent compact models have suffered from accuracy issues due to the use of qualitative approximation, rather than mathematically correct solutions to the ambipolar diffusion equation. A practical consequence of this inaccuracy is that a given model calibration is trustworthy over only a narrow range of operating conditions. This report describes work to produce improved compact models for photocurrent. Specifically, an analytic model is developed for epitaxial diode structures that have a highly doped subcollector. The analytic model is compared with both numerical TCAD calculations, as well as the compact model described in reference [2]. The new analytic model compares well against TCAD over a wide range of operating conditions, and is shown to be superior to the compact model from reference [2].
Swaminathan, Madhavan
system become increasingly more critical regarding the signal integrity and electromagnetic interference electromagnetic interference. Hence, accurate modeling of power/ground planes is critical to estimate the noise
John Bulava; Philip Gerhold; Karl Jansen; Jim Kallarackal; Attila Nagy
2011-11-11T23:59:59.000Z
We study a chirally invariant Higgs-Yukawa model regulated on a space-time lattice. We calculate Higgs boson resonance parameters and mass bounds for various values of the mass of the degenerate fermion doublet. Also, first results on the phase transition temperature are presented. In general, this model may be relevant for BSM scenarios with a heavy fourth generation of quarks.
AN IMPLICIT 2-D DEPTH-AVERAGED FINITE-VOLUME MODEL OF FLOW AND SEDIMENT TRANSPORT IN COASTAL WATERS
US Army Corps of Engineers
diffusion induced by currents, waves and wave breaking. The model uses a quadtree rectangular mesh. However, because of the dynamic nature of currents and waves on the coast, neither bed load nor suspended with the spectral wave transformation model called CMS-Wave, which solves the steady-state wave-action balance
E-Print Network 3.0 - art finite element Sample Search Results
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
system. We generated finite element models of the Boeing 767 and of the top 20 stories of the North Tower... elements. The finite ... Source: Irfanoglu, Ayhan - School of...
Bobby S Acharya; Michael R Douglas
2006-06-21T23:59:59.000Z
We present evidence that the number of string/$M$ theory vacua consistent with experiments is a finite number. We do this both by explicit analysis of infinite sequences of vacua and by applying various mathematical finiteness theorems.
Tabares-Velasco, P. C.; Christensen, C.; Bianchi, M.; Booten, C.
2012-07-01T23:59:59.000Z
Phase change materials (PCMs) represent a potential technology to reduce peak loads and HVAC energy consumption in buildings. There are few building energy simulation programs that have the capability to simulate PCM but their accuracy has not been completely tested. This report summarizes NREL efforts to develop diagnostic tests cases to obtain accurate energy simulations when PCMs are modeled in residential buildings.
Harrison, Mark
, isotropic, composite system consisting of a fluid-filled well bore Qf through a fluid-saturated porous solid-filled borehole Qf through a fluid-saturated porous solid Qp. The problem arises naturally in acoustic well in the model. This paper is related to several previous works on the subject. The theory of propagation
Doswell III, Charles A.
Multicellular Convection ADRIAN M. LOFTUS* School of Meteorology, University of Oklahoma, Norman, Oklahoma DANIEL B. WEBER Center for Analysis and Prediction of Storms, University of Oklahoma, Norman, Oklahoma CHARLES A. DOSWELL III Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma
Thomas, Jeremy N.
in Argentina during the Sprite2006 Campaign in Brazil F. T. São Sabbas,1 M. J. Taylor,2 P.D. Pautet,2 M. Bailey convective system (MCS) over Argentina, as part of the third sprite campaign in Brazil. GOES infrared (IR a mesoscale convective system in Argentina during the Sprite2006 Campaign in Brazil, J. Geophys. Res., 115, A
Larval fish assemblages and mesoscale oceanographic structure along the Mesoamerican Barrier Reef Caribbean region, and contains spawning sites for a number of reef fish species. Despite this, little is known of the distribution and transport of pelagic fish larvae in the area, and basic in situ
Combustion in Meso-scale Vortex Chambers Ming-hsun Wu*
Yang, Vigor
%. For propane/air combustion, the stability limits ranged from ~ 0.25 to 2 for the 124 mm3 combustor. Methane of a small combustor not only makes the heat generated from the combustion process hard to keep pace1 Combustion in Meso-scale Vortex Chambers Ming-hsun Wu* , Yanxing Wang, Vigor Yang and Richard A
Zhang, Da-Lin
ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 27, NO. 2, 2010, 243252 Mesoscale Barotropic Instability of Vortex Rossby Waves in Tropical Cyclones ZHONG Wei1 ( Í), LU Han-Cheng1 (ö ), and Da-Lin ZHANG2 1 Institute of Meteorology, PLA University of Science and Technology, Nanjing 211101 2 Department
Ebert, Beth
and an objectbased approach E. M. C. Demaria,1 D. A. Rodriguez,2 E. E. Ebert,3 P. Salio,4 F. Su,5 and J. B. Valdes1 to precipitation was mitigating the effect of the errors. Citation: Demaria, E. M. C., D. A. Rodriguez, E. E. Ebert, P. Salio, F. Su, and J. B. Valdes (2011), Evaluation of mesoscale convective systems in South
Karl-Ludwig Kratz; Khalil Farouqi; Peter Mller
2014-06-10T23:59:59.000Z
Theoretical studies of the nucleosynthesis origin of the heavy elements in our Solar System (S.S.) by the rapid neutron-capture process (r-process) still face the entwined uncertainties in the possible astrophysical scenarios and the nuclear-physics properties far from stability. In this paper we present results from the investigation of an r-process in the high-entropy wind (HEW) of core-collapse supernovae (here chosen as one of the possible scenarios for this nucleosynthesis process), using new nuclear-data input calculated in a consistent approach, for masses and $\\beta$-decay properties from the new finite-range droplet model FRDM(2012). The accuracy of the new mass model is 0.56 MeV with respect to {\\sc AME2003}, to which it was adjusted. We compare the new HEW r-process abundance pattern to the latest S.S. r-process residuals and to our earlier calculations with the nuclear-structure quantities based on FRDM(1992). Substantial overall and specific local improvements in the calculated pattern of the r-process between $A\\simeq 110$ and $^{209}$Bi, as well as remaining deficiencies are discussed in terms of the underlying spherical and deformed shell structure far from stability.
Yeh, G.T.
1987-08-01T23:59:59.000Z
The 3DFEMWATER model is designed to treat heterogeneous and anisotropic media consisting of as many geologic formations as desired, consider both distributed and point sources/sinks that are spatially and temporally dependent, accept the prescribed initial conditions or obtain them by simulating a steady state version of the system under consideration, deal with a transient head distributed over the Dirichlet boundary, handle time-dependent fluxes due to pressure gradient varying along the Neumann boundary, treat time-dependent total fluxes distributed over the Cauchy boundary, automatically determine variable boundary conditions of evaporation, infiltration, or seepage on the soil-air interface, include the off-diagonal hydraulic conductivity components in the modified Richards equation for dealing with cases when the coordinate system does not coincide with the principal directions of the hydraulic conductivity tensor, give three options for estimating the nonlinear matrix, include two options (successive subregion block iterations and successive point interactions) for solving the linearized matrix equations, automatically reset time step size when boundary conditions or source/sinks change abruptly, and check the mass balance computation over the entire region for every time step. The model is verified with analytical solutions or other numerical models for three examples.
Extremality of translation-invariant phases for a finite-state SOS-model on the binary tree
C. Kuelske; U. A. Rozikov
2014-11-21T23:59:59.000Z
We consider the SOS (solid-on-solid) model, with spin values $0,1,2$, on the Cayley tree of order two (binary tree). We treat both ferromagnetic and antiferromagnetic coupling, with interactions which are proportional to the absolute value of the spin differences. We present a classification of all translation-invariant phases (splitting Gibbs measures) of the model: We show uniqueness in the case of antiferromagnetic interactions, and existence of up to seven phases in the case of ferromagnetic interactions, where the number of phases depends on the interaction strength. Next we investigate whether these states are extremal or non-extremal in the set of all Gibbs measures, when the coupling strength is varied, whenever they exist. We show that two states are always extremal, two states are always non-extremal, while three of the seven states make transitions between extremality and non-extremality. We provide explicit bounds on those transition values, making use of algebraic properties of the models, and an adaptation of the method of Martinelli, Sinclair, Weitz.
Mesoscale Simulations of a Wind Ramping Event for Wind Energy Prediction
Rhodes, M; Lundquist, J K
2011-09-21T23:59:59.000Z
Ramping events, or rapid changes of wind speed and wind direction over a short period of time, present challenges to power grid operators in regions with significant penetrations of wind energy in the power grid portfolio. Improved predictions of wind power availability require adequate predictions of the timing of ramping events. For the ramping event investigated here, the Weather Research and Forecasting (WRF) model was run at three horizontal resolutions in 'mesoscale' mode: 8100m, 2700m, and 900m. Two Planetary Boundary Layer (PBL) schemes, the Yonsei University (YSU) and Mellor-Yamada-Janjic (MYJ) schemes, were run at each resolution as well. Simulations were not 'tuned' with nuanced choices of vertical resolution or tuning parameters so that these simulations may be considered 'out-of-the-box' tests of a numerical weather prediction code. Simulations are compared with sodar observations during a wind ramping event at a 'West Coast North America' wind farm. Despite differences in the boundary-layer schemes, no significant differences were observed in the abilities of the schemes to capture the timing of the ramping event. As collaborators have identified, the boundary conditions of these simulations probably dominate the physics of the simulations. They suggest that future investigations into characterization of ramping events employ ensembles of simulations, and that the ensembles include variations of boundary conditions. Furthermore, the failure of these simulations to capture not only the timing of the ramping event but the shape of the wind profile during the ramping event (regardless of its timing) indicates that the set-up and execution of such simulations for wind power forecasting requires skill and tuning of the simulations for a specific site.
A multiscale preconditioner for stochastic mortar mixed finite elements
Yotov, Ivan
physical models in different subdomains. The mortar finite element method is a generalization is the stochastic collocation method [4,40,39]. It combines a finite element discretiza- tion in physical space the approximation properties of the stochastic finite element method [5,37], making it more efficient than MCS
2003-12-06T23:59:59.000Z
FVE is closely related to the control volume finite element method ... simple stencils, to apply to a fairly wide range of fluid flow equations, to effectively treat.
Hoeth, Brian Richard
2012-06-07T23:59:59.000Z
This study provides a detailed analysis of cloud-to-aphics. ground (CG) lightning flashes within individual Mesoscale Convective Systems (MCSs) that occurred in the Central United States during May-August of 1992 and 1993. Analysis of the CG...
Hodapp, Charles Lee
2009-05-15T23:59:59.000Z
originated in the convective or transition regions. Both in-situ charging mechanisms created by the development of the mesoscale updraft and charge advection by the front-to-rear flow likely contribute to the increased electrification and lightning...
Mechem, David B.; Chen, Shuyi S.; Houze, Robert A. Jr.
2006-04-01T23:59:59.000Z
Momentum transport by the stratiform components of mesoscale convective systems (MCSs) during the Tropical OceanGlobal Atmosphere Coupled OceanAtmosphere Response Experiment in December 1992 is investigated using a ...
Modeling, Analysis and Simulation of Multiscale Preferential Flow - 8/05-8/10 - Final Report
Ralph Showalter; Malgorzata Peszynska
2012-07-03T23:59:59.000Z
The research agenda of this project are: (1) Modeling of preferential transport from mesoscale to macroscale; (2) Modeling of fast flow in narrow fractures in porous media; (3) Pseudo-parabolic Models of Dynamic Capillary Pressure; (4) Adaptive computational upscaling of flow with inertia from porescale to mesoscale; (5) Adaptive modeling of nonlinear coupled systems; and (6) Adaptive modeling and a-posteriori estimators for coupled systems with heterogeneous data.
Rushing, John Ford
2014-04-25T23:59:59.000Z
potential laboratory tests, (b) comparisons of laboratory tests results to full-scale accelerated pavement test results, and (c) analyses of results from finite element simulations. The laboratory study evaluated of the repeated load test, the static creep...
Mesoscale fracture fabric and paleostress along the San Andreas fault at SAFOD
Almeida, Rafael Vladimir
2009-05-15T23:59:59.000Z
Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Judith Chester Committee Members, Frederick Chester David Schechter Head of Department... of Advisory Committee: Dr. Judith Chester Spot cores from Phase 1 drilling of the main borehole at the San Andreas Fault Observatory at Depth (SAFOD) were mapped to characterize the mesoscale structure and infer paleostress at depth. Cores were oriented...
Representation of the mesoscale wind field using a line integral technique
Trares, John S
1982-01-01T23:59:59.000Z
REPPESENTATION OF THE MESOSCALE WIND FIELD USING A LINE INTEGRAL TECHNII1UE A Thesis by JOHN SEBASTIAN TRARES, JR. Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE May 1982 Major Subject: Meteorology REPRESENTATION OF THE HESOSCALE WIND FIELD USING A LINE INTEGRAL TECHNIQUE A Thesis by JOHN SESASTIAN TRARES, JR. Approved as to style and content by: Chairman of Committee Nember ember Head of Depar...
Alexandre Nicolas; Francesco Puosi; Hideyuki Mizuno; Jean-Louis Barrat
2015-03-05T23:59:59.000Z
Shear transformations (i.e., localised rearrangements of particles resulting in the shear deformation of a small region of the sample) are the building blocks of mesoscale models for the flow of disordered solids. In order to compute the time-dependent response of the solid material to such a shear transformation, with a proper account of elastic heterogeneity and shear wave propagation, we propose and implement a very simple Finite-Element (FE) -based method. Molecular Dynamics (MD) simulations of a binary Lennard-Jones glass are used as a benchmark for comparison, and information about the microscopic viscosity and the local elastic constants is directly extracted from the MD system and used as input in FE. We find very good agreement between FE and MD regarding the temporal evolution of the disorder-averaged displacement field induced by a shear transformation, which turns out to coincide with the response of a uniform elastic medium. However, fluctuations are relatively large, and their magnitude is satisfactorily captured by the FE simulations of an elastically heterogeneous system. Besides, accounting for elastic anisotropy on the mesoscale is not crucial in this respect. The proposed method thus paves the way for models of the rheology of amorphous solids which are both computationally efficient and realistic, in that structural disorder and inertial effects are accounted for.
Analysis of azimuthal mode dynamics of mesoscale eddies
McCalpin, John David
1984-01-01T23:59:59.000Z
Rossby wave modes. The results appear to be in excellent qualitative agree- ment with Fli erl's (1977) analytic solutions. But the real advantage to numerical simulation is in the application to nonlinear models and arbitrary initial conditions. Mc...Wi lli ams and Fli erl ( 1979) presented the results of an extensive parameter survey using their two-mode non- linear quasigeostrophic model. The primary result is that nonlinear processes impede dispersion in intense vortices, so that friction be...
Upscaling Calcite Growth Rates From the Mesoscale to the Macroscale
Bracco, Jacquelyn N [ORNL; Stack, Andrew G [ORNL; Steefel, Carl I [Lawrence Berkeley National Laboratory (LBNL)
2013-01-01T23:59:59.000Z
Quantitative prediction of mineral reaction rates in the subsurface remains a daunting task partly because a key parameter for macroscopic models, the reactive site density, is poorly constrained. Here we report atomic force microscopy (AFM) measurements on the calcite surface of monomolecular step densities, treated as equivalent to the reactive site density, as a function of aqueous calcium-to-carbonate ratio and saturation index. Data for the obtuse step orientation are combined with existing step velocity measurements to generate a model that predicts overall macroscopic calcite growth rates. The model is quantitatively consistent with several published macroscopic rates under a range of alkaline solution conditions, particularly for two of the most comprehensive data sets without the need for additional fit parameters. The model reproduces peak growth rates and its functional form is simple enough to be incorporated into reactive transport or other macroscopic models designed for predictions in porous media. However, it currently cannot model equilibrium, pH effects, and may overestimate rates at high aqueous calcium-to-carbonate ratios. The discrepancies in rates at high calcium-to-carbonate ratios may be due to differences in pre-treatment, such as exposing the seed material to SI 1.0 to generate/develop growth hillocks, or other factors.
Thirumalai, Devarajan
Finite-temperature phase diagram of nonmagnetic impurities in high-temperature superconductors to the superconducting phase in cuprates which is eliminated for p 0.05; in the same region for these dilute impurity destruction of the superconducting phase.1,2 In yttrium barium copper oxide YBCO , the transition temperature
Choi, Myunghee [Retired] [Retired; Chan, Vincent S. [General Atomics] [General Atomics
2014-02-28T23:59:59.000Z
This final report describes the work performed under U.S. Department of Energy Cooperative Agreement DE-FC02-08ER54954 for the period April 1, 2011 through March 31, 2013. The goal of this project was to perform iterated finite-orbit Monte Carlo simulations with full-wall fields for modeling tokamak ICRF wave heating experiments. In year 1, the finite-orbit Monte-Carlo code ORBIT-RF and its iteration algorithms with the full-wave code AORSA were improved to enable systematical study of the factors responsible for the discrepancy in the simulated and the measured fast-ion FIDA signals in the DIII-D and NSTX ICRF fast-wave (FW) experiments. In year 2, ORBIT-RF was coupled to the TORIC full-wave code for a comparative study of ORBIT-RF/TORIC and ORBIT-RF/AORSA results in FW experiments.
Finite N from Resurgent Large N
Couso-Santamara, Ricardo; Vaz, Ricardo
2015-01-01T23:59:59.000Z
Due to instanton effects, gauge-theoretic large N expansions yield asymptotic series, in powers of 1/N^2. The present work shows how to generically make such expansions meaningful via their completion into resurgent transseries, encoding both perturbative and nonperturbative data. Large N resurgent transseries compute gauge-theoretic finite N results nonperturbatively (no matter how small N is). Explicit calculations are carried out within the gauge theory prototypical example of the quartic matrix model. Due to integrability in the matrix model, it is possible to analytically compute (fixed integer) finite N results. At the same time, the large N resurgent transseries for the free energy of this model was recently constructed. Together, it is shown how the resummation of the large N resurgent transseries matches the analytical finite N results up to remarkable numerical accuracy. Due to lack of Borel summability, Stokes phenomena has to be carefully taken into account, implying that instantons play a dominan...
Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping1 Peter Gaube ,Dudley B. Chelton;Three mechanisms for self-induced Ekman pumping in the interiors of mesoscale ocean eddies temperature (SST) field, which generates a stress curl and therefore Ekman pumping in regions of crosswind SST
Samelson, Roger
Satellite Observations of Mesoscale Eddy-Induced Ekman Pumping1 Peter Gaube ,Dudley B. Chelton;Three mechanisms for self-induced Ekman pumping in the interiors of mesoscale ocean eddies generates a curl of the stress and therefore Ekman pumping in regions of crosswind SST gradients
Hartley, Roger
ARCHITECTURE OF THE MERCURY MESOSCALE METEOROLOGICAL DATA FUSION C. Fields, C. Cavendish, M. Coombs Atmospheric Sciences Laboratory White Sands Missile Range, NM 88002-5501 USA 1. INTRODUCTION The MERCURY) that require meteorological data as input (McWilliams or al., this volume). MERCURY addresses, at the mesoscale
Diurnal cycle of air pollution in the Kathmandu Valley, Nepal: 2. Modeling results
Panday, Arnico K.
After completing a 9-month field experiment studying air pollution and meteorology in the Kathmandu Valley, Nepal, we set up the mesoscale meteorological model MM5 to simulate the Kathmandu Valley's meteorology with a ...
FINITE DISJUNCTIVE PROGRAMMING CHARACTERIZATIONS ...
2010-03-07T23:59:59.000Z
In this paper, we give a finite disjunctive programming procedure to obtain .... In this paper, assuming a nonempty feasible set and bounded general integer variables ..... to find the last node ? on the path from the root node such that xk ? C?. There are two ..... http://arxiv.org/PS cache/arxiv/pdf/0707/0707.3945v1.pdf.
Finite generation conjectures for cohomology over finite fields.
Thomas H Geisser
We construct an intermediate cohmology between motivic cohomology and Weil-etale cohomology. Using this, the Bass conjecture on finite generation of motivic cohomology, and the Beilinson-Tate on the finite generation of Weil-etale cohomology are related.
Design and fabrication of a meso-scale stirling engine and combustor.
Echekki, Tarek (Sandia National Laboratories, Livermore, CA); Haroldsen, Brent L. (Sandia National Laboratories, Livermore, CA); Krafcik, Karen L. (Sandia National Laboratories, Livermore, CA); Morales, Alfredo Martin (Sandia National Laboratories, Livermore, CA); Mills, Bernice E. (Sandia National Laboratories, Livermore, CA); Liu, Shiling (Sandia National Laboratories, Livermore, CA); Lee, Jeremiah C. (Sandia National Laboratories, Livermore, CA); Karpetis, Adionos N. (Sandia National Laboratories, Livermore, CA); Chen, Jacqueline H. (Sandia National Laboratories, Livermore, CA); Ceremuga, Joseph T. (Sandia National Laboratories, Livermore, CA); Raber, Thomas N. (Sandia National Laboratories, Livermore, CA); Hekmuuaty, Michelle A. (Sandia National Laboratories, Livermore, CA)
2005-05-01T23:59:59.000Z
Power sources capable of supplying tens of watts are needed for a wide variety of applications including portable electronics, sensors, micro aerial vehicles, and mini-robotics systems. The utility of these devices is often limited by the energy and power density capabilities of batteries. A small combustion engine using liquid hydrocarbon fuel could potentially increase both power and energy density by an order of magnitude or more. This report describes initial development work on a meso-scale external combustion engine based on the Stirling cycle. Although other engine designs perform better at macro-scales, we believe the Stirling engine cycle is better suited to small-scale applications. The ideal Stirling cycle requires efficient heat transfer. Consequently, unlike other thermodynamic cycles, the high heat transfer rates that are inherent with miniature devices are an advantage for the Stirling cycle. Furthermore, since the Stirling engine uses external combustion, the combustor and engine can be scaled and optimized semi-independently. Continuous combustion minimizes issues with flame initiation and propagation. It also allows consideration of a variety of techniques to promote combustion that would be difficult in a miniature internal combustion engine. The project included design and fabrication of both the engine and the combustor. Two engine designs were developed. The first used a cylindrical piston design fabricated with conventional machining processes. The second design, based on the Wankel rotor geometry, was fabricated by through-mold electroforming of nickel in SU8 and LIGA micromolds. These technologies provided the requisite precision and tight tolerances needed for efficient micro-engine operation. Electroformed nickel is ideal for micro-engine applications because of its high strength and ductility. A rotary geometry was chosen because its planar geometry was more compatible with the fabrication process. SU8 lithography provided rapid prototypes to verify the design. A final high precision engine was created via LIGA. The micro-combustor was based on an excess enthalpy concept. Development of a micro-combustor included both modeling and experiments. We developed a suite of simulation tools both in support of the design of the prototype combustors, and to investigate more fundamental aspects of combustion at small scales. Issues of heat management and integration with the micro-scale Stirling engine were pursued using CFD simulations. We found that by choice of the operating conditions and channel dimensions energy conversion occurs by catalysis-dominated or catalysis-then-homogeneous phase combustion. The purpose of the experimental effort in micro-combustion was to study the feasibility and explore the design parameters of excess enthalpy combustors. The efforts were guided by the necessity for a practical device that could be implemented in a miniature power generator, or as a stand-alone device used for heat generation. Several devices were fabricated and successfully tested using methane as the fuel.
FINITE-EXTENT K-2 KINEMATIC SOURCE
Cerveny, Vlastislav
FINITE-EXTENT K-2 KINEMATIC SOURCE MODELLING: THE 1999 ATHENS EARTHQUAKE STRONG. Direct S-waves are presumably dominant in the wave field, so these waves only are taken into account the strongest (S-wave) phase. In spite of many simplifying assumptions, namely omitting the site effects
EXPANDED MIXED FINITE ELEMENT METHODS FOR QUASILINEAR SECOND ORDER ELLIPTIC PROBLEMS, II
EXPANDED MIXED FINITE ELEMENT METHODS FOR QUASILINEAR SECOND ORDER ELLIPTIC PROBLEMS, II Zhangxin coefficient times the gradient). Based on this formulation, mixed finite element approximations with low permeability and to the transport equation with small dispersion in groundwater modeling
Prentiss, Mara
Mesoscale Self-Assembly: Capillary Bonds and Negative Menisci Ned Bowden, Scott R. J. Oliver., Cambridge, Massachusetts 02138 ReceiVed: September 2, 1999 This paper describes the self-assembly) that examined the self-assembly of hexagonal plates of PDMS (F ) 1.05 g/cm3) that had a density close
Johnson, Richard H.
October 1986 R. H. Johnson 721 Lower-Tropospheric Warming and Drying in Tropical Mesoscale Convective Systems: Implications for the Problem of Cumulus Parameterization By Richard H. Johnson Department beneath the stratiform com- ponents of these systems (Houze, 1977; Zipser, 1977; Johnson and Kriete, 1982
Finite group symmetry breaking
G. Gaeta
2005-10-02T23:59:59.000Z
Finite group symmetry is commonplace in Physics, in particular through crystallographic groups occurring in condensed matter physics -- but also through the inversions (C,P,T and their combinations) occurring in high energy physics and field theory. The breaking of finite groups symmetry has thus been thoroughly studied, and general approaches exist to investigate it. In Landau theory, the state of a system is described by a finite dimensional variable (the {\\it order parameter}), and physical states correspond to minima of a potential, invariant under a group. In this article we describe the basics of symmetry breaking analysis for systems described by a symmetric polynomial; in particular we discuss generic symmetry breakings, i.e. those determined by the symmetry properties themselves and independent on the details of the polynomial describing a concrete system. We also discuss how the plethora of invariant polynomials can be to some extent reduced by means of changes of coordinates, i.e. how one can reduce to consider certain types of polynomials with no loss of generality. Finally, we will give some indications on extension of this theory, i.e. on how one deals with symmetry breakings for more general groups and/or more general physical systems.
Yang, Xiujun
2009-05-15T23:59:59.000Z
through complex geological models. In recent years, a significant amount of work has been done in our group using 2D finite-difference modeling. For complex salt structures which exploration and pro- duction industries meet today, 2D finite...
Mechanical instability at finite temperature
Xiaoming Mao; Anton Souslov; Carlos I. Mendoza; T. C. Lubensky
2014-07-08T23:59:59.000Z
Many physical systems including lattices near structural phase transitions, glasses, jammed solids, and bio-polymer gels have coordination numbers that place them at the edge of mechanical instability. Their properties are determined by an interplay between soft mechanical modes and thermal fluctuations. In this paper we investigate a simple square-lattice model with a $\\phi^4$ potential between next-nearest-neighbor sites whose quadratic coefficient $\\kappa$ can be tuned from positive negative. We show that its zero-temperature ground state for $\\kappa power-law behavior of the shear modulus as a function of temperature. We expect our study to provide a general framework for the study of finite-temperature mechanical and phase behavior of other systems with a large number of floppy modes.
3.021J / 1.021J / 10.333J / 18.361J / 22.00J Introduction to Modeling and Simulation, Spring 2008
Buehler, Markus
This course explores the basic concepts of computer modeling and simulation in science and engineering. We'll use techniques and software for simulation, data analysis and visualization. Continuum, mesoscale, atomistic and ...
Cardin, Julien; Dufour, Christian; Gourbilleau, Fabrice
2015-01-01T23:59:59.000Z
A comparative study of the gain achievement is performed in a waveguide optical amplifier whose active layer is constituted by a silica matrix containing silicon nanograins acting as sensitizer of either neodymium ions (Nd 3+) or erbium ions (Er 3+). Due to the large difference between population levels characteristic times (ms) and finite-difference time step (10 --17 s), the conventional auxiliary differential equation and finite-difference time-domain (ADE-FDTD) method is not appropriate to treat such systems. Consequently, a new two loops algorithm based on ADE-FDTD method is presented in order to model this waveguide optical amplifier. We investigate the steady states regime of both rare earth ions and silicon nanograins levels populations as well as the electromagnetic field for different pumping powers ranging from 1 to 10 4 mW.mm-2. Furthermore, the three dimensional distribution of achievable gain per unit length has been estimated in this pumping range. The Nd 3+ doped waveguide shows a higher gross...
Caesar, Kathy-Ann Lois
1995-01-01T23:59:59.000Z
Mesoscale convective systems (MCSs) are known to cool the subcloud layer by the introduction of penetrative downdrafts to the surface, resulting in the formation of cold domes (also known as cold pools). Five MCSs sampled during the Tropical Ocean...
Tonks, Michael R. [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Zhang, Yongfeng [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Bai, Xianming [Idaho National Laboratory (INL), Idaho Falls, ID (United States)
2014-06-01T23:59:59.000Z
This report summarizes development work funded by the Nuclear Energy Advanced Modeling Simulation program's Fuels Product Line (FPL) to develop a mechanistic model for the average grain size in UO? fuel. The model is developed using a multiscale modeling and simulation approach involving atomistic simulations, as well as mesoscale simulations using INL's MARMOT code.
Finite element analysis of human joints
Bossart, P.L.; Hollerbach, K.
1996-09-01T23:59:59.000Z
Our work focuses on the development of finite element models (FEMs) that describe the biomechanics of human joints. Finite element modeling is becoming a standard tool in industrial applications. In highly complex problems such as those found in biomechanics research, however, the full potential of FEMs is just beginning to be explored, due to the absence of precise, high resolution medical data and the difficulties encountered in converting these enormous datasets into a form that is usable in FEMs. With increasing computing speed and memory available, it is now feasible to address these challenges. We address the first by acquiring data with a high resolution C-ray CT scanner and the latter by developing semi-automated method for generating the volumetric meshes used in the FEM. Issues related to tomographic reconstruction, volume segmentation, the use of extracted surfaces to generate volumetric hexahedral meshes, and applications of the FEM are described.
King, Joshua David
2005-02-17T23:59:59.000Z
to simulate CSEM experiments. The objective of the present study is to model the changes in electromagnetic response for a resistive disk and a more geometrically complex structure, which are rough approximations of hydrocarbon reservoirs. The parameters...
Rainfall-Runoff Modelling of Meso-Scale Catchments in the Upper Ewaso
Richner, Heinz
, but growing demand for irrigation water on its foothills produces water shortage in the lowlands. Water founded River Water Users Associations, but their work is hindered by a lack of knowledge on the present and future availability of water resources. This study tries to make a contribution to better water
Surface Stresses and Turbulent Fluxes: Problems in Mesoscale Modeling over Terrain
: Turbulent mixing in breaking waves (Epifanio and Qian, 2008) LES for breaking mountain wave Flow past a hill) = Dx Ly (u, v, w) = Dy One kinematic condition (no flow through the boundary): w = u h x + v h y at the boundary and combine with the kinematic condition Lx ui,j,0 vi,j,0 wi,j,0 = f (Dx i,j , interior) , Ly
Humbert, Mark Edward
1980-01-01T23:59:59.000Z
with convection is upward motion at all levels with a maximum value just prior to max1mum convect1ve intensity. Days without convection showed a cont1nual vertical turbulent m1xing of moisture from a shallow boundary layer to the 700 mb level. Lack... of 4 g kg 1 are observed. The moisture content increases at the 22 Post Big Spring Midland Robert Lee 4 500 mb cn 0 O m 8 L. cn 6 x 4 2 700 mb . . ~ ''. ~' . ~ / r 12 10 850 mb 15 18 21 00 03 Time (GNT hours) Fig. 9. Time profiles...
Author's personal copy Mesoscale modeling of electric double layer capacitors with three-dimensional
Pilon, Laurent
, cylindrical, and spherical electrodes or pores. EDLCs with highly ordered porous electrodes. EDLC with ordered bimodal meso- porous formulations for simulating electric double layer capacitors (EDLCs) with three-dimensional ordered structures
Finite generation of Tate cohomology.
Jon F. Carlson; Sunil K. Chebolu; Jan Minac.; 15 (2011) 244-257
Let G be a finite group and let k be a field of characteristic p. Given a finitely generated indecomposable non-projective kG-module M, we conjecture that if the Tate cohomology $\\HHHH^*(G, M)$ of G with coefficients in M is finitely generated over the Tate cohomology ring $\\HHHH^*(G, k)$, then the support variety V_G(M) of M is equal to the entire maximal ideal spectrum V_G(k). We prove various results which support this conjecture. The converse of this conjecture is established for modules in the connected component of k in the stable Auslander-Reiten quiver for kG, but it is shown to be false in general. It is also shown that all finitely generated kG-modules over a group G have finitely generated Tate cohomology if and only if G has periodic cohomology.
Pugh, Mary
and the thermoelectric material. The new model is especially useful when an accurate picture of transients materials with a high thermoelectric figure of merit to convert heat to electricity [3]. Despite relatively and application interest in thermoelectric materials has been in thin films [5], [6] and the design of microscale
Assessment of Molecular Modeling & Simulation
None
2002-01-03T23:59:59.000Z
This report reviews the development and applications of molecular and materials modeling in Europe and Japan in comparison to those in the United States. Topics covered include computational quantum chemistry, molecular simulations by molecular dynamics and Monte Carlo methods, mesoscale modeling of material domains, molecular-structure/macroscale property correlations like QSARs and QSPRs, and related information technologies like informatics and special-purpose molecular-modeling computers. The panel's findings include the following: The United States leads this field in many scientific areas. However, Canada has particular strengths in DFT methods and homogeneous catalysis; Europe in heterogeneous catalysis, mesoscale, and materials modeling; and Japan in materials modeling and special-purpose computing. Major government-industry initiatives are underway in Europe and Japan, notably in multi-scale materials modeling and in development of chemistry-capable ab-initio molecular dynamics codes.
Measuring kinetic energy changes in the mesoscale with low acquisition rates
Roldn, . [ICFOInstitut de Cincies Fotniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona) (Spain); GISCGrupo Interdisciplinar de Sistemas Complejos, Madrid (Spain); Martnez, I. A.; Rica, R. A., E-mail: rul@ugr.es [ICFOInstitut de Cincies Fotniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona) (Spain); Dinis, L. [GISCGrupo Interdisciplinar de Sistemas Complejos, Madrid (Spain); Departamento de Fsica Atmica, Molecular y Nuclear, Universidad Complutense de Madrid, 28040 Madrid (Spain)
2014-06-09T23:59:59.000Z
We report on the measurement of the average kinetic energy changes in isothermal and non-isothermal quasistatic processes in the mesoscale, realized with a Brownian particle trapped with optical tweezers. Our estimation of the kinetic energy change allows to access to the full energetic description of the Brownian particle. Kinetic energy estimates are obtained from measurements of the mean square velocity of the trapped bead sampled at frequencies several orders of magnitude smaller than the momentum relaxation frequency. The velocity is tuned applying a noisy electric field that modulates the amplitude of the fluctuations of the position and velocity of the Brownian particle, whose motion is equivalent to that of a particle in a higher temperature reservoir. Additionally, we show that the dependence of the variance of the time-averaged velocity on the sampling frequency can be used to quantify properties of the electrophoretic mobility of a charged colloid. Our method could be applied to detect temperature gradients in inhomogeneous media and to characterize the complete thermodynamics of biological motors and of artificial micro and nanoscopic heat engines.
Impact of mesoscale eddies on water transport between the Pacific Ocean and the Bering Sea
Prants, S V; Budyansky, M V; Uleysky, M Yu
2013-01-01T23:59:59.000Z
Sea surface height anomalies observed by satellites in 1993--2012 are combined with simulation and observations by surface drifters and Argo floats to study water flow pattern in the Near Strait (NS) connected the Pacific Ocean with the Bering Sea. Daily Lagrangian latitudinal maps, computed with the AVISO surface velocity field, and calculation of the transport across the strait show that the flow through the NS is highly variable and controlled by mesoscale and submesoscale eddies in the area. On the seasonal scale, the flux through the western part of the NR is negatively correlated with the flux through its eastern part ($r=-0.93$). On the interannual time scale, a significant positive correlation ($r=0.72$) is diagnosed between the NS transport and the wind stress in winter. Increased southward component of the wind stress decreases the northward water transport through the strait. Positive wind stress curl over the strait area in winter--spring generates the cyclonic circulation and thereby enhances the...
Sales, James Gregory
1994-01-01T23:59:59.000Z
stratigraphy typical ol North American thrust belts (Figure 3) where the horizontal permeability of Layer 3 is ten times the vertical permeability. 49 23 a) Total pore pressure, b) excess pore pressure, c) ). , and d) temperature, for a stratigraphy... typical of North American thrust belts (Figure 3) where the horizontal pcrmcahility of Layer 3 is one-hundred times the vertical permeability. 50 24 a) Total pore pressure, b) excess porc prcssure, c) X, and d) tcmpcraturc, for "standard" model...
Discontinuous Galerkin finite element methods for gradient plasticity.
Garikipati, Krishna. (University of Michigan, Ann Arbor, MI); Ostien, Jakob T.
2010-10-01T23:59:59.000Z
In this report we apply discontinuous Galerkin finite element methods to the equations of an incompatibility based formulation of gradient plasticity. The presentation is motivated with a brief overview of the description of dislocations within a crystal lattice. A tensor representing a measure of the incompatibility with the lattice is used in the formulation of a gradient plasticity model. This model is cast in a variational formulation, and discontinuous Galerkin machinery is employed to implement the formulation into a finite element code. Finally numerical examples of the model are shown.
Quantum Mechanics associated with a Finite Group
Robert W. Johnson
2006-04-20T23:59:59.000Z
I describe, in the simplified context of finite groups and their representations, a mathematical model for a physical system that contains both its quantum and classical aspects. The physically observable system is associated with the space containing elements fxf for f an element in the regular representation of a given finite group G. The Hermitian portion of fxf is the Wigner distribution of f whose convolution with a test function leads to a mathematical description of the quantum measurement process. Starting with the Jacobi group that is formed from the semidirect product of the Heisenberg group with its automorphism group SL(2,F{N}) for N an odd prime number I show that the classical phase space is the first order term in a series of subspaces of the Hermitian portion of fxf that are stable under SL(2,F{N}). I define a derivative that is analogous to a pseudodifferential operator to enable a treatment that parallels the continuum case. I give a new derivation of the Schrodinger-Weil representation of the Jacobi group. Keywords: quantum mechanics, finite group, metaplectic. PACS: 03.65.Fd; 02.10.De; 03.65.Ta.
INTRODUCTION TO THE FINITE ELEMENT METHOD
California at Berkeley, University of
in popularity with the finite difference method in the areas of heat transfer and fluid mechanics. 1DRAFT Chapter 1 INTRODUCTION TO THE FINITE ELEMENT METHOD 1.1 Historical perspective: the origins of the finite el- ement method The finite element method constitutes a general tool for the numerical solution
Mattison, Kevin Morgan
1992-01-01T23:59:59.000Z
ON THE EFFECT OF THE STRA 'Y-STATE APPROXIMATION IN TIME-SPACE COMPOSITE STUDIES OF MESOSCALE CONVECTIVE SYSTEMS A Thesis KEVIN MORGAN MATTISON Subnitted to the Office of Graduate Studies of Texas A&M University in partial fulfillnent... of the requirements for the degree of MASTER OF SCIENCE Decenber 1992 Major Subject: Meteorology ON THE EFFECT OF THE STEADY-STATE APPROXINATIOH IN TIME-SPACE COMPOSITE STUDIES OF NESOSCALE COHVECTIVE SYSTENS A Thesis KEVIN MORGAN NATTISOH Approved as to style...
Dr. David Whitfield; Dr. Daniel Hyams
2009-09-14T23:59:59.000Z
In Year 1 of this project, items 1.1 and 1.2 were addressed, as well as item 2.2. The baseline parallel computational simulation tool has been refined significantly over the timeline of this project for the purpose of atmospheric dispersion and transport problems; some of these refinements are documented in Chapter 3. The addition of a concentration transport capability (item 1.2) was completed, along with validation and usage in a highly complex urban environment. Multigrid capability (item 2.2) was a primary focus of Year 1 as well, regardless of the fact that it was scheduled for Year 2. It was determined by the authors that due to the very large nature of the meshes required for atmospheric simulations at mesoscale, multigrid was a key enabling technology for the rest of the project to be successful. Therefore, it was addressed early according to the schedule laid out in the original proposal. The technology behind the multigrid capability is discussed in detail in Chapter 5. Also in Year 1, the issue of ground topography specification is addressed. For simulations of pollutant transport in a given region, a key prerequisite is the specification of the detailed ground topography. The local topography must be placed into a form suitable for generating an unstructured grid both on the topography itself and the atmospheric volume above it; this effort is documented in Chapter 6. In Year 2 of this project, items 1.3 and 2.1 were addressed. Weather data in the form of wind speeds, relative humidity, and baseline pollution levels may be input into the code in order to improve the real-world fidelity of the solutions. Of course, the computational atmospheric boundary layer (ABL) boundary condition developed in Year 1 may still be used when necessary. Cloud cover may be simulated via the levels of actinic flux allowed in photochemical reactions in the atmospheric chemistry model. The primary focus of Year 2 was the formulation of a multispecies capability with included chemical reactions (item 2.1). This proved to be a very arduous task, taking the vast majority of the time and personnel allocation for Year Two. The addition of this capability and related verification is documented in Chapter 7. A discussion of available tropospheric chemistry models is located in Chapter 8; and, a technology demonstrator for the full multispecies capability is detailed in Chapter 9. Item 2.3 has been partially addressed, in that the computation of sensitivity derivatives have been incorporated in the Tenasi code [7]. However, it has not been utilized in this project in order to compute probability distribution functions for pollutant deposition. In order to completely address the integration of weather and sensor data into the code (item 1.3) and integrate with existing sensor networks (item 3.1), a customizable interface was established. Weather data is most commonly available via a real database, and as such, support for accessing these databases is present in the solver source code. For integration functionality, a method of dynamic code customization was developed in Year 3, which is documented in Chapter 11.
Relativistic Random Phase Approximation At Finite Temperature
Niu, Y. F. [State Key Laboratory for Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Physics Department, Faculty of Science, University of Zagreb (Croatia); Paar, N.; Vretenar, D. [Physics Department, Faculty of Science, University of Zagreb (Croatia); Meng, J. [State Key Laboratory for Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China)
2009-08-26T23:59:59.000Z
The fully self-consistent finite temperature relativistic random phase approximation (FTRRPA) has been established in the single-nucleon basis of the temperature dependent Dirac-Hartree model (FTDH) based on effective Lagrangian with density dependent meson-nucleon couplings. Illustrative calculations in the FTRRPA framework show the evolution of multipole responses of {sup 132}Sn with temperature. With increased temperature, in both monopole and dipole strength distributions additional transitions appear in the low energy region due to the new opened particle-particle and hole-hole transition channels.
Our scenario is akin to the magnetic furnace model proposed by Axford and
Pe'er, Dana
Our scenario is akin to the magnetic furnace model proposed by Axford and McKenzie (1416) and to ideas invoking reconnection of mesoscale loops (38, 39). We adopt from the furnace model the idea. However, our model of the nascent solar wind is intrinsically 3-D, and the magnetic field geometry
HERMES: A Model to Describe Deformation, Burning, Explosion, and Detonation
Reaugh, J E
2011-11-22T23:59:59.000Z
HERMES (High Explosive Response to MEchanical Stimulus) was developed to fill the need for a model to describe an explosive response of the type described as BVR (Burn to Violent Response) or HEVR (High Explosive Violent Response). Characteristically this response leaves a substantial amount of explosive unconsumed, the time to reaction is long, and the peak pressure developed is low. In contrast, detonations characteristically consume all explosive present, the time to reaction is short, and peak pressures are high. However, most of the previous models to describe explosive response were models for detonation. The earliest models to describe the response of explosives to mechanical stimulus in computer simulations were applied to intentional detonation (performance) of nearly ideal explosives. In this case, an ideal explosive is one with a vanishingly small reaction zone. A detonation is supersonic with respect to the undetonated explosive (reactant). The reactant cannot respond to the pressure of the detonation before the detonation front arrives, so the precise compressibility of the reactant does not matter. Further, the mesh sizes that were practical for the computer resources then available were large with respect to the reaction zone. As a result, methods then used to model detonations, known as {beta}-burn or program burn, were not intended to resolve the structure of the reaction zone. Instead, these methods spread the detonation front over a few finite-difference zones, in the same spirit that artificial viscosity is used to spread the shock front in inert materials over a few finite-difference zones. These methods are still widely used when the structure of the reaction zone and the build-up to detonation are unimportant. Later detonation models resolved the reaction zone. These models were applied both to performance, particularly as it is affected by the size of the charge, and to situations in which the stimulus was less than that needed for reliable performance, whether as a result of accident, hazard, or a fault in the detonation train. These models describe the build-up of detonation from a shock stimulus. They are generally consistent with the mesoscale picture of ignition at many small defects in the plane of the shock front and the growth of the resulting hot-spots, leading to detonation in heterogeneous explosives such as plastic-bonded explosives (PBX). The models included terms for ignition, and also for the growth of reaction as tracked by the local mass fraction of product gas, {lambda}. The growth of reaction in such models incorporates a form factor that describes the change of surface area per unit volume (specific surface area) as the reaction progresses. For unimolecular crystalline-based explosives, the form factor is consistent with the mesoscale picture of a galaxy of hot spots burning outward and eventually interacting with each other. For composite explosives and propellants, where the fuel and oxidizer are segregated, the diffusion flame at the fuel-oxidizer interface can be interpreted with a different form factor that corresponds to grains burning inward from their surfaces. The form factor influences the energy release rate, and the amount of energy released in the reaction zone. Since the 19th century, gun and cannon propellants have used perforated geometric shapes that produce an increasing surface area as the propellant burns. This helps maintain the pressure as burning continues while the projectile travels down the barrel, which thereby increases the volume of the hot gas. Interior ballistics calculations use a geometric form factor to describe the changing surface area precisely. As a result, with a suitably modified form factor, detonation models can represent burning and explosion in damaged and broken reactant. The disadvantage of such models in application to accidents is that the ignition term does not distinguish between a value of pressure that results from a shock, and the same pressure that results from a more gradual increase. This disagrees with experiments, where
An integrated model for the post-solidification shape and grain morphology of fusion welds
Kidess, Anton; Duggan, Gregory; Browne, David J; Kenjere, Saa; Richardson, Ian; Kleijn, Chris R
2015-01-01T23:59:59.000Z
Through an integrated macroscale/mesoscale computational model, we investigate the developing shape and grain morphology during the melting and solidification of a weld. In addition to macroscale surface tension driven fluid flow and heat transfer, we predict the solidification progression using a mesoscale model accounting for realistic solidification kinetics, rather than quasi-equilibrium thermodynamics. The tight coupling between the macroscale and the mesoscale distinguishes our results from previously published studies. The inclusion of Marangoni driven fluid flow and heat transfer, both during heating and cooling, was found to be crucial for accurately predicting both weld pool shape and grain morphology. However, if only the shape of the weld pool is of interest, a thermodynamic quasi-equilibrium solidification model, neglecting solidification kinetics, was found to suffice when including fluid flow and heat transfer. We demonstrate that the addition of a sufficient concentration of approximately 1 $\\...
Finite element simulation and parameter optimization of a flexible tactile pressure sensor array
Lee, Shira M. (Shira Miriam)
2005-01-01T23:59:59.000Z
A finite element model was developed to optimize design of a flexible tactile sensor. The sensor consists of layers of thin-film copper and PDMS, and the model can be used to determine the effects on sensor sensitivity and ...
DOLFIN: Automated Finite Element Computing
Logg, Anders; Wells, G N
2009-01-01T23:59:59.000Z
delec 1980]. (4) L2-conforming finite elements: (a) DGq, arbitrary degree discontinuous Lagrange elements; and (b) CR1, first degree CrouzeixRaviart5 elements [Crouzeix and Raviart 1973]. Arbitrary combinations of the above elements may be used to define...
Quantum Chemistry at Finite Temperature
Liqiang Wei
2006-05-23T23:59:59.000Z
In this article, we present emerging fields of quantum chemistry at finite temperature. We discuss its recent developments on both experimental and theoretical fronts. First, we describe several experimental investigations related to the temperature effects on the structures, electronic spectra, or bond rupture forces for molecules. These include the analysis of the temperature impact on the pathway shifts for the protein unfolding by atomic force microscopy (AFM), the temperature dependence of the absorption spectra of electrons in solvents, and the temperature influence over the intermolecular forces measured by the AFM. On the theoretical side, we review advancements made by the author in the coming fields of quantum chemistry at finite temperature. Starting from the Bloch equation, we have derived the sets of hierarchy equations for the reduced density operators in both canonical and grand canonical ensembles. They provide a law according to which the reduced density operators vary in temperature for the identical and interacting many-body systems. By taking the independent particle approximation, we have solved the equations in the case of a grand canonical ensemble, and obtained an energy eigenequation for the molecular orbitals at finite temperature. The explicit expression for the temperature-dependent Fock operator is also given. They form a mathematical foundation for the examination of the molecular electronic structures and their interplay with finite temperature. Moreover, we clarify the physics concerning the temperature effects on the electronic structures or processes of the molecules, which is crucial for both theoretical understanding and computation. Finally, ....
Businger, Steven
technological advances in our ability to forecast cyclogenesis, one cannot say that the cyclone problem to probe the mesoscale structure and evolution of winter cyclones in recent years. Many recent advances treatment of their dynamics. Kraus and Businger (1994) review the air-sea interaction in cyclones, and Houze
Topological clusters in SU(2) gluodynamics at finite T and
Topological clusters in SU(2) gluodynamics at finite T and the evidence for KvB calorons E'2005, Trinity College, Dublin July 25 to 30, 2005 #12;Overview Content · Introduction · The SU(2) KvB Caloron · Caloron-like Structures in Monte-Carlo Samples ? · A Stochastic Caloron Model · Summary
An Efficient Probabilistic Finite Element Method for Stochastic Groundwater Flow
Osnes, Harald
of groundwater flow and transport from mathematical models involves considerable uncertainty due to the presenceAn Efficient Probabilistic Finite Element Method for Stochastic Groundwater Flow Harald Osnes Hans by nonlinear effects as oe Y approaches unity in more general domains. 1 #12; 1 Introduction The prediction
Parity-odd and CPT-even electrodynamics of the SME at Finite Temperature
Rodolfo Casana; Manoel M. Ferreira Jr; Madson R. O. Silva
2009-10-19T23:59:59.000Z
This work examines the finite temperature properties of the CPT-even and parity-odd electrodynamics of the standard model extension. We start from the partition function written into the functional integral formalism in Ref. \\cite{Finite}. After specializing the Lorentz-violating tensor $ W_{\\alpha \
CharacteristicGalerkin and Mixed Finite Element Approximation of Contamination by Compressible
Chou, So-Hsiang
CharacteristicGalerkin and Mixed Finite Element Approximation of Contamination by Compressibledisposal contamination in porous media is modeled by a coupled system of partial differential equations for the brine, radionuclides, and heat and by a mixed finite element method for the pressure and velocity
LOCKING-FREE FINITE ELEMENT METHOD FOR A BENDING MOMENT FORMULATION OF TIMOSHENKO BEAMS
Rodríguez, Rodolfo
LOCKING-FREE FINITE ELEMENT METHOD FOR A BENDING MOMENT FORMULATION OF TIMOSHENKO BEAMS FELIPE LEPE for Timo- shenko beams. It is known that standard finite elements applied to this model lead to wrong results when the thickness of the beam t is small. Here, we consider a mixed formulation in terms
Determination of fracture toughness of AZ31 Mg alloy using the cohesive finite element method
Chen, Long-Qing
Determination of fracture toughness of AZ31 Mg alloy using the cohesive finite element method X Received in revised form 21 June 2012 Accepted 11 August 2012 Keywords: Fracture toughness Cohesive finite is to develop a micromechanical approach for determining the fracture toughness. A phase-field model for grain
Ewing, Richard E.
A ThreeDimensional Finite Element Simulation for Transport of Nuclear Waste Contamination of South Carolina, Columbia, South Carolina ABSTRACT: Model equations for transport of nuclearwaste based up on the inherent physics. A threedimensional finite element method for nuclear waste
Plasma conductivity at finite coupling
Babiker Hassanain; Martin Schvellinger
2011-08-31T23:59:59.000Z
By taking into account the full order(\\alpha'^3) type IIB string theory corrections to the supergravity action, we compute the leading finite 't Hooft coupling order(\\lambda^{-3/2}) corrections to the conductivity of strongly-coupled SU(N) {\\cal {N}}=4 supersymmetric Yang-Mills plasma in the large N limit. We find that the conductivity is enhanced by the corrections, in agreement with the trend expected from previous perturbative weak-coupling computations.
Impeller deflection and modal finite element analysis.
Spencer, Nathan A.
2013-10-01T23:59:59.000Z
Deflections of an impeller due to centripetal forces are calculated using finite element analysis. The lateral, or out of plane, deflections are an important design consideration for this particular impeller because it incorporates an air bearing with critical gap tolerances. The target gap distance is approximately 10 microns at a rotational velocity of 2500 rpm. The centripetal forces acting on the impeller cause it deflect in a concave fashion, decreasing the initial gap distance as a function of radial position. This deflection is characterized for a previous and updated impeller design for comparative purposes. The impact of design options such as material selection, geometry dimensions, and operating rotational velocity are also explored, followed by a sensitivity study with these parameters bounded by specific design values. A modal analysis is also performed to calculate the impeller's natural frequencies which are desired to be avoided during operation. The finite element modeling techniques continue to be exercised by the impeller design team to address specific questions and evaluate conceptual designs, some of which are included in the Appendix.
Model Wind over the Central and Southern California Coastal Ocean HSIAO-MING HSU
Model Wind over the Central and Southern California Coastal Ocean HSIAO-MING HSU National Center of high-resolution wind in coastal ocean modeling. This paper tests the Coupled OceanAtmosphere Mesoscale Prediction System (COAMPS) at the 9-, 27-, and 81-km grid resolutions in simulating wind off the central
Development of an Adjoint for a Complex Atmospheric Model, the ARPS, using TAF
Gao, Jidong
, such as operational weather predictions models, pose challenges on the applicability of AD tools. We report- ational weather prediction models are much more complex, and the problem sizes tend to be much larger as a system for mesoscale and storm-scale numerical weather prediction as well as a wide range of idealized
Application of Mass Lumped Higher Order Finite Elements
Chen, J.; Strauss, H. R.; Jardin, S. C.; Park, W.; Sugiyama, L. E.; Fu., G.; Breslau, J.
2005-11-01T23:59:59.000Z
There are many interesting phenomena in extended-MHD such as anisotropic transport, mhd, 2-fluid effects stellarator and hot particles. Any one of them challenges numerical analysts, and researchers are seeking for higher order methods, such as higher order finite difference, higher order finite elements and hp/spectral elements. It is true that these methods give more accurate solution than their linear counterparts. However, numerically they are prohibitively expensive. Here we give a successful solution of this conflict by applying mass lumped higher order finite elements. This type of elements not only keep second/third order accuracy but also scale closely to linear elements by doing mass lumping. This is especially true for second order lump elements. Full M3D and anisotropic transport models are studied.
Patrinoiu, Greta; Caldern-Moreno, Jose Maria; Culita, Daniela C. [Illie Murgulescu Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest (Romania); Birjega, Ruxandra [National Institute for Lasers, Plasma and Radiation Physics, P.O. Box Mg27, Magurele, Bucharest (Romania); Ene, Ramona [Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest (Romania); Carp, Oana, E-mail: ocarp@icf.ro [Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest (Romania)
2013-06-15T23:59:59.000Z
A green template route for the synthesis of mesoscale solid ZnO spheres was ascertained. The protocol involves a double coating of the carbonaceous spheres with successive layers of zinc-containing species by alternating a non-ultrasound and ultrasound-assisted deposition, followed by calcination treatments. The composites were characterized by FTIR spectroscopy, thermal analysis, scanning electron microscopy while the obtained ZnO spheres by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, N{sub 2} adsorptiondesorption isotherms and photoluminescence investigations. A growth mechanism of the solid spheres is advanced based on these results. While the spheres' diameters and the mean size values of ZnO are independent on deposition order, the surface area and the external porosity are fairly dependent. The photoluminescence measurements showed interesting emission features, with emission bands in the violet to orange region. The spheres present high photocatalytical activity towards the degradation of phenol under UV irradiation, the main reaction being its mineralization. - Graphical abstract: A novel and eco-friendly methodology for the synthesis of mesoscale solid ZnO spheres was developed. The protocol involves a double coating of the starch-derived carbonaceous spheres with successive layers of zinc-containing species by alternating a non-ultrasound and ultrasound-assisted deposition, followed by calcination treatments. - Highlights: ZnO solid spheres are obtained via a template route using carbonaceous spheres. Two-step coatings of interchangeable order are used as deposition procedure. The coating procedure influences the porosity and surface area. ZnO spheres exhibited interesting visible photoluminescence properties. Solid spheres showed photocatalytical activity in degradation of phenol.
Finite temperature Casimir effect for graphene
Ignat V. Fialkovsky; Valery N. Marachevsky; Dmitri V. Vassilevich
2011-02-09T23:59:59.000Z
We adopt the Dirac model for quasiparticles in graphene and calculate the finite temperature Casimir interaction between a suspended graphene layer and a parallel conducting surface. We find that at high temperature the Casimir interaction in such system is just one half of that for two ideal conductors separated by the same distance. In this limit single graphene layer behaves exactly as a Drude metal. In particular, the contribution of the TE mode is suppressed, while one of the TM mode saturates the ideal metal value. Behaviour of the Casimir interaction for intermediate temperatures and separations accessible for an experiment is studied in some detail. We also find an interesting interplay between two fundamental constants of graphene physics: the fine structure constant and the Fermi velocity.
On the secure obfuscation of deterministic finite automata.
Anderson, William Erik
2008-06-01T23:59:59.000Z
In this paper, we show how to construct secure obfuscation for Deterministic Finite Automata, assuming non-uniformly strong one-way functions exist. We revisit the software protection approaches originally proposed by [5, 10, 12, 17] and revise them to the current obfuscation setting of Barak et al. [2]. Under this model, we introduce an efficient oracle that retains some 'small' secret about the original program. Using this secret, we can construct an obfuscator and two-party protocol that securely obfuscates Deterministic Finite Automata against malicious adversaries. The security of this model retains the strong 'virtual black box' property originally proposed in [2] while incorporating the stronger condition of dependent auxiliary inputs in [15]. Additionally, we show that our techniques remain secure under concurrent self-composition with adaptive inputs and that Turing machines are obfuscatable under this model.
Magnetic insulation at finite temperatures
Goedecke, G. H.; Davis, Brian T.; Chen, Chiping [Physics Department, New Mexico State University, Las Cruces, New Mexico 88003 and Raytheon Missile Systems, 1151 E. Hermans Road, Tucson, Arizona 85706 (United States); Intense Beam Theoretical Research Group, Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 and Raytheon Missile Systems, 1151 E. Hermans Road, Tucson, Arizona 85706 (United States)
2006-08-15T23:59:59.000Z
A finite-temperature non-neutral plasma (FTNNP) theory of magnetically insulated (MI) electron flows in crossed-field vacuum devices is developed and applied in planar geometry. It is shown that, in contrast to the single type of MI flow predicted by traditional cold-plasma treatments, the nonlinear FTNNP equations admit five types of steady flow, of which three types are MI flows, including flows in which the electric field and/or the tangential velocity at the cathode may be zero or nonzero. It is also shown that finite-temperature Vlasov-Poisson treatments yield solutions for electron number densities and electrostatic potentials that are a subset of the FTNNP solutions. The algorithms that are used to solve the FTNNP equations numerically are discussed, and the numerical results are presented for several examples of the three types of MI flow. Results include prediction of the existence, boundaries, number density profiles, and other properties of sheaths of electrons in the anode-cathode gap.
Final Report for Integrated Multiscale Modeling of Molecular Computing Devices
Glotzer, Sharon C.
2013-08-28T23:59:59.000Z
In collaboration with researchers at Vanderbilt University, North Carolina State University, Princeton and Oakridge National Laboratory we developed multiscale modeling and simulation methods capable of modeling the synthesis, assembly, and operation of molecular electronics devices. Our role in this project included the development of coarse-grained molecular and mesoscale models and simulation methods capable of simulating the assembly of millions of organic conducting molecules and other molecular components into nanowires, crossbars, and other organized patterns.
Finite element approximation of coupled seismic and ...
zyserman
layer, having a thickness of about 10 nm. Finite element approximation of coupled seismic and electromagnetic waves in gas hydrate-bearing sediments p.
RESIDUALLY FINITE DIMENSIONAL C*-ALGEBRAS AND ...
2000-04-27T23:59:59.000Z
finite-dimensional C*-algebra embeds in the CAR algebra (the UHF algebra of type. 2?). ... Throughout the paper we let B denote the CAR algebra, B ?= ?. ?.
An application of stochastic finite element method in structural reliabiity
Agrawal, Sanjay
1993-01-01T23:59:59.000Z
OF SCIENCE August 1993 Major Subject: Civil Engineering AN APPLICATION OF STOCHASTIC FINITE ELEMENT METHOD IN STRUCTURAL RELIABILITY A Thesis by SANJAY AGRAWAL Approved as to style and content by: Kostas apadimitriou (Chair of Committee) John M... of the beam on the buckling load. The statistical methodology can be efficiently used with available FORM/SORM reliability techniques to compute the probability of failure of the beam due to buckling. Random fields are used to quantify the modeling...
Frequency-Domain Modeling Techniques for the Scalar Wave Equation : An Introduction
Ajo-Franklin, Jonathan B.
2005-01-01T23:59:59.000Z
Frequency-domain finite-difference (FDFD) modeling offers several advantages over traditional timedomain
Evans, Jason
-level water consumption were more than doubled relative to simulations that did not incorporate MODIS data. 1. Introduction The dual pressures of local water consumption and global climate change threaten of potential evapotranspiration (PET) from the surface (Penman 1948). Surface conditions, including soil mois
Development of a Meso-Scale Material Model for Ballistic Fabric and Its Use in Flexible-Armor
Grujicic, Mica
.g., as reinforcements in rigid polymer matrix composites, PMCs, for lightweight vehicle- armor systems). Flexible-amide) fabric and an E-glass fiber/ethyl cellulose composite in body-armor systems can be linked to the Korean of the body- armor vests relative to up to 0.30 caliber threats, ceramic insert strike-plates are commonly
Heinemann, Detlev
.physik.uni-oldenburg.de/ehf *GKSS Research Center Geesthacht, Max-Planck-Stra?e 1, D-21494 Geesthacht, Germany To asses wind has been developed at the GKSS Research Center in Geesthacht, Germany ([8]). It numerically solves
Smith, K. Shafer
. SHAFER SMITH Center for Atmosphere Ocean Science, Courant Institute of Mathematical Sciences, New York
Theoretical investigation of finite size effects at DNA melting
Buyukdagli, S; Buyukdagli, Sahin; Joyeux, Marc
2007-01-01T23:59:59.000Z
We investigated how the finiteness of the length of the sequence affects the phase transition that takes place at DNA melting temperature. For this purpose, we modified the Transfer Integral method to adapt it to the calculation of both extensive (partition function, entropy, specific heat, etc) and non-extensive (order parameter and correlation length) thermodynamic quantities of finite sequences with open boundary conditions, and applied the modified procedure to two different dynamical models. We showed that rounding of the transition clearly takes place when the length of the sequence is decreased. We also performed a finite-size scaling analysis of the two models and showed that the singular part of the free energy can indeed be expressed in terms of an homogeneous function. However, both the correlation length and the average separation between paired bases diverge at the melting transition, so that it is no longer clear to which of these two quantities the length of the system should be compared. Moreo...
Omega3P: A Parallel Finite-Element Eigenmode Analysis Code for Accelerator Cavities
Lee, Lie-Quan; Li, Zenghai; Ng, Cho; Ko, Kwok; /SLAC
2009-03-04T23:59:59.000Z
Omega3P is a parallel eigenmode calculation code for accelerator cavities in frequency domain analysis using finite-element methods. In this report, we will present detailed finite-element formulations and resulting eigenvalue problems for lossless cavities, cavities with lossy materials, cavities with imperfectly conducting surfaces, and cavities with waveguide coupling. We will discuss the parallel algorithms for solving those eigenvalue problems and demonstrate modeling of accelerator cavities through different examples.
Coastal Wave Generation and Wave Breaking over Terrain: Two Problems in Mesoscale Wave Dynamics
Qian, Tingting
2010-07-14T23:59:59.000Z
and idealized numerical modeling. The linear theory for ow without terrain shows that the solution depends on two parameters: a nondimensional coastal width L and a nondimensional wind speed U. For U 6= 0 the solution is composed of three distinct wave branches...
North Pacific Mesoscale Coupled Air-Ocean Simulations Compared with Observations
Koracin, Darko; Cerovecki, Ivana; Vellore, Ramesh; Mejia, John; Hatchett, Benjamin; McCord, Travis; McLean, Julie; Dorman, Clive
2013-04-11T23:59:59.000Z
Executive summary The main objective of the study was to investigate atmospheric and ocean interaction processes in the western Pacific and, in particular, effects of significant ocean heat loss in the Kuroshio and Kuroshio Extension regions on the lower and upper atmosphere. It is yet to be determined how significant are these processes are on climate scales. The understanding of these processes led us also to development of the methodology of coupling the Weather and Research Forecasting model with the Parallel Ocean Program model for western Pacific regional weather and climate simulations. We tested NCAR-developed research software Coupler 7 for coupling of the WRF and POP models and assessed its usability for regional-scale applications. We completed test simulations using the Coupler 7 framework, but implemented a standard WRF model code with options for both one- and two-way mode coupling. This type of coupling will allow us to seamlessly incorporate new WRF updates and versions in the future. We also performed a long-term WRF simulation (15 years) covering the entire North Pacific as well as high-resolution simulations of a case study which included extreme ocean heat losses in the Kuroshio and Kuroshio Extension regions. Since the extreme ocean heat loss occurs during winter cold air outbreaks (CAO), we simulated and analyzed a case study of a severe CAO event in January 2000 in detail. We found that the ocean heat loss induced by CAOs is amplified by additional advection from mesocyclones forming on the southern part of the Japan Sea. Large scale synoptic patterns with anomalously strong anticyclone over Siberia and Mongolia, deep Aleutian Low, and the Pacific subtropical ridge are a crucial setup for the CAO. It was found that the onset of the CAO is related to the breaking of atmospheric Rossby waves and vertical transport of vorticity that facilitates meridional advection. The study also indicates that intrinsic parameterization of the surface fluxes within the WRF model needs more evaluation and analysis.
Ultraviolet extrapolations in finite oscillator bases
S. Knig; S. K. Bogner; R. J. Furnstahl; S. N. More; T. Papenbrock
2014-12-29T23:59:59.000Z
The use of finite harmonic oscillator spaces in many-body calculations introduces both infrared (IR) and ultraviolet (UV) errors. The IR effects are well approximated by imposing a hard-wall boundary condition at a properly identified radius L_eff. We show that duality of the oscillator implies that the UV effects are equally well described by imposing a sharp momentum cutoff at a momentum Lambda_eff complementary to L_eff. By considering two-body systems with separable potentials, we show that the UV energy corrections depend on details of the potential, in contrast to the IR energy corrections, which depend only on the S-matrix. An adaptation of the separable treatment to more general interactions is developed and applied to model potentials as well as to the deuteron with realistic potentials. The previous success with a simple phenomenological form for the UV error is also explained. Possibilities for controlled extrapolations for A > 2 based on scaling arguments are discussed.
Finite temperature topological order in 2D topological color codes
Mehdi Kargarian
2009-07-19T23:59:59.000Z
In this work the topological order at finite temperature in two-dimensional color code is studied. The topological entropy is used to measure the behavior of the topological order. Topological order in color code arises from the colored string-net structures. By imposing the hard constrained limit the exact solution of the entanglement entropy becomes possible. For finite size systems, by raising the temperature, one type of string-net structure is thermalized and the associative topological entropy vanishes. In the thermodynamic limit the underlying topological order is fragile even at very low temperatures. Taking first the thermodynamic limit and then the zero-temperature limit and vice versa does not commute, and their difference is related only to the topology of regions. The contribution of the colors and symmetry of the model in the topological entropy is also discussed. It is shown how the gauge symmetry of the color code underlies the topological entropy.
Correction due to finite speed of light in absolute gravimeters
Nagornyi, V D; Zanimonskiy, Y Y
2010-01-01T23:59:59.000Z
Correction due to finite speed of light is among the most inconsistent ones in absolute gravimetry. Formulas reported by different authors yield corrections scattered up to 8 $\\mu$Gal with no obvious reasons. The problem, though noted before, has never been studied, and nowadays the correction is rather postulated than rigorously proven. In this paper we investigate the problem from several prospectives, find the corrections for different types of absolute gravimeters, and establish relationships between different ways of implement them. The obtained results enabled us to analyze and understand the discrepancies in the results of other authors. We found that the correction derived from the Doppler effect is accountable only for $\\tfrac{2}{3}$ of the total correction due to finite speed of light, if no signal delays are considered. Another major source of inconsistency was found in the tacit use of simplified trajectory models.
Serrato, M. G.
2013-09-27T23:59:59.000Z
The DOE Office of Environmental management (DOE EM) faces the challenge of decommissioning thousands of excess nuclear facilities, many of which are highly contaminated. A number of these excess facilities are massive and robust concrete structures that are suitable for isolating the contained contamination for hundreds of years, and a permanent decommissioning end state option for these facilities is in situ decommissioning (ISD). The ISD option is feasible for a limited, but meaningfull number of DOE contaminated facilities for which there is substantial incremental environmental, safety, and cost benefits versus alternate actions to demolish and excavate the entire facility and transport the rubble to a radioactive waste landfill. A general description of an ISD project encompasses an entombed facility; in some cases limited to the blow-grade portion of a facility. However, monitoring of the ISD structures is needed to demonstrate that the building retains its structural integrity and the contaminants remain entombed within the grout stabilization matrix. The DOE EM Office of Deactivation and Decommissioning and Facility Engineering (EM-13) Program Goal is to develop a monitoring system to demonstrate long-term performance of closed nuclear facilities using the ISD approach. The Savannah River National Laboratory (SRNL) has designed and implemented the In Situ Decommissioning Sensor Network, Meso-Scale Test Bed (ISDSN-MSTB) to address the feasibility of deploying a long-term monitoring system into an ISD closed nuclear facility. The ISDSN-MSTB goal is to demonstrate the feasibility of installing and operating a remote sensor network to assess cementitious material durability, moisture-fluid flow through the cementitious material, and resulting transport potential for contaminate mobility in a decommissioned closed nuclear facility. The original ISDSN-MSTB installation and remote sensor network operation was demonstrated in FY 2011-12 at the ISDSN-MSTB test cube located at the Florida International University Applied Research Center, Miami, FL (FIU-ARC). A follow-on fluid injection test was developed to detect fluid and ion migration in a cementitious material/grouted test cube using a limited number of existing embedded sensor systems. This In Situ Decommissioning Sensor Network, Meso-Scale Test Bed (ISDSN-MSTB) - Phase 3 Fluid Injection Test Summary Report summarizes the test implementation, acquired and processed data, and results from the activated embedded sensor systems used during the fluid injection test. The ISDSN-MSTB Phase 3 Fluid Injection Test was conducted from August 27 through September 6, 2013 at the FIU-ARC ISDSN-MSTB test cube. The fluid injection test activated a portion of the existing embedded sensor systems in the ISDSN-MSTB test cube: Electrical Resistivity Tomography-Thermocouple Sensor Arrays, Advance Tensiometer Sensors, and Fiber Loop Ringdown Optical Sensors. These embedded sensor systems were activated 15 months after initial placement. All sensor systems were remotely operated and data acquisition was completed through the established Sensor Remote Access System (SRAS) hosted on the DOE D&D Knowledge Management Information Tool (D&D DKM-IT) server. The ISDN Phase 3 Fluid Injection Test successfully demonstrated the feasibility of embedding sensor systems to assess moisture-fluid flow and resulting transport potential for contaminate mobility through a cementitious material/grout monolith. The ISDSN embedded sensor systems activated for the fluid injection test highlighted the robustness of the sensor systems and the importance of configuring systems in-depth (i.e., complementary sensors and measurements) to alleviate data acquisition gaps.
adaptive finite element: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
properties and performance of the adaptive finite element approach to the design of nano-photonic components. Central issues are the construction of vectorial finite elements...
adaptive finite elements: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
properties and performance of the adaptive finite element approach to the design of nano-photonic components. Central issues are the construction of vectorial finite elements...
Santarpia, Joshua
2001-01-01T23:59:59.000Z
interest in using it to study severe weather. Mesoscale vortices that are often asso- ciated with severe storms such as supercells and bow echoes have been of particular interest. One of the first discussions of this type of circulation is from Brooks... radar echoes associated with a tornado indicating a cyclonic circulation. He likened the structure to that of a small-scale hurricane. Ray's (1976) dual-Doppler radar analysis of a supercell storm was the first to show a vortex pair and strong cy...
Rother, Gernot [ORNL; Vlcek, Lukas [ORNL; Gruszkiewicz, Miroslaw {Mirek} S [ORNL; Chialvo, Ariel A [ORNL; Anovitz, Lawrence {Larry} M [ORNL; Banuelos, Jose Leo [ORNL; Wallacher, Dirk [Helmholtz-Zentrum Berlin; Grimm, Nico [Helmholtz-Zentrum Berlin; Cole, David [Ohio State University
2014-01-01T23:59:59.000Z
Adsorption of supercritical CO2 in nanoporous silica aerogel was investigated by a combination of experiments and molecular-level computer modeling. High-pressure gravimetric and vibrating tube densimetry techniques were used to measure the mean pore fluid density and excess sorption at 35 C and 50 C and pressures of 0-200 bar. Densification of the pore fluid was observed at bulk fluid densities below 0.7 g/cm3. Far above the bulk fluid density, near-zero sorption or weak depletion effects were measured, while broad excess sorption maxima form in the vicinity of the bulk critical density region. The CO2 sorption properties are very similar for two aerogels with different bulk densities of 0.1 g/cm3 and 0.2 g/cm3, respectively. The spatial distribution of the confined supercritical fluid was analyzed in terms of sorption- and bulk-phase densities by means of the Adsorbed Phase Model (APM), which used data from gravimetric sorption and small-angle neutron scattering experiments. To gain more detailed insight into supercritical fluid sorption, large-scale lattice gas GCMC simulations were utilized and tuned to resemble the experimental excess sorption data. The computed three-dimensional pore fluid density distributions show that the observed maximum of the excess sorption near the critical density originates from large density fluctuations pinned to the pore walls. At this maximum, the size of these fluctuations is comparable to the prevailing pore sizes.
3-D Finite Element Analyses of the Egan Cavern Field
Klamerus, E.W.; Ehgartner, B.L.
1999-02-01T23:59:59.000Z
Three-dimensional finite element analyses were performed for the two gas-filled storage caverns at the Egan field, Jennings dome, Louisiana. The effects of cavern enlargement on surface subsidence, storage loss, and cavern stability were investigated. The finite element model simulated the leaching of caverns to 6 and 8 billion cubic feet (BCF) and examined their performance at various operating conditions. Operating pressures varied from 0.15 psi/ft to 0.9 psi/ft at the bottom of the lowest cemented casing. The analysis also examined the stability of the web or pillar of salt between the caverns under differential pressure loadings. The 50-year simulations were performed using JAC3D, a three dimensional finite element analysis code for nonlinear quasistatic solids. A damage criterion based on onset of dilatancy was used to evaluate cavern instability. Dilation results from the development of microfractures in salt and, hence, potential increases in permeability onset occurs well before large scale failure. The analyses predicted stable caverns throughout the 50-year period for the range of pressures investigated. Some localized salt damage was predicted near the bottom walls of the caverns if the caverns are operated at minimum pressure for long periods of time. Volumetric cavern closures over time due to creep were moderate to excessive depending on the salt creep properties and operating pressures. However, subsidence above the cavern field was small and should pose no problem, to surface facilities.
Theory of finite-entanglement scaling at one-dimensional quantum critical points
Frank Pollmann; Subroto Mukerjee; Ari Turner; Joel E. Moore
2009-04-20T23:59:59.000Z
Studies of entanglement in many-particle systems suggest that most quantum critical ground states have infinitely more entanglement than non-critical states. Standard algorithms for one-dimensional many-particle systems construct model states with limited entanglement, which are a worse approximation to quantum critical states than to others. We give a quantitative theory of previously observed scaling behavior resulting from finite entanglement at quantum criticality: the scaling theory of finite entanglement is only superficially similar to finite-size scaling, and has a different physical origin. We find that finite-entanglement scaling is governed not by the scaling dimension of an operator but by the "central charge" of the critical point, which counts its universal degrees of freedom. An important ingredient is the recently obtained universal distribution of density-matrix eigenvalues at a critical point\\cite{calabrese1}. The parameter-free theory is checked against numerical scaling at several quantum critical points.
Preliminary Phase Field Computational Model Development
Li, Yulan; Hu, Shenyang Y.; Xu, Ke; Suter, Jonathan D.; McCloy, John S.; Johnson, Bradley R.; Ramuhalli, Pradeep
2014-12-15T23:59:59.000Z
This interim report presents progress towards the development of meso-scale models of magnetic behavior that incorporate microstructural information. Modeling magnetic signatures in irradiated materials with complex microstructures (such as structural steels) is a significant challenge. The complexity is addressed incrementally, using the monocrystalline Fe (i.e., ferrite) film as model systems to develop and validate initial models, followed by polycrystalline Fe films, and by more complicated and representative alloys. In addition, the modeling incrementally addresses inclusion of other major phases (e.g., martensite, austenite), minor magnetic phases (e.g., carbides, FeCr precipitates), and minor nonmagnetic phases (e.g., Cu precipitates, voids). The focus of the magnetic modeling is on phase-field models. The models are based on the numerical solution to the Landau-Lifshitz-Gilbert equation. From the computational standpoint, phase-field modeling allows the simulation of large enough systems that relevant defect structures and their effects on functional properties like magnetism can be simulated. To date, two phase-field models have been generated in support of this work. First, a bulk iron model with periodic boundary conditions was generated as a proof-of-concept to investigate major loop effects of single versus polycrystalline bulk iron and effects of single non-magnetic defects. More recently, to support the experimental program herein using iron thin films, a new model was generated that uses finite boundary conditions representing surfaces and edges. This model has provided key insights into the domain structures observed in magnetic force microscopy (MFM) measurements. Simulation results for single crystal thin-film iron indicate the feasibility of the model for determining magnetic domain wall thickness and mobility in an externally applied field. Because the phase-field model dimensions are limited relative to the size of most specimens used in experiments, special experimental methods were devised to create similar boundary conditions in the iron films. Preliminary MFM studies conducted on single and polycrystalline iron films with small sub-areas created with focused ion beam have correlated quite well qualitatively with phase-field simulations. However, phase-field model dimensions are still small relative to experiments thus far. We are in the process of increasing the size of the models and decreasing specimen size so both have identical dimensions. Ongoing research is focused on validation of the phase-field model. Validation is being accomplished through comparison with experimentally obtained MFM images (in progress), and planned measurements of major hysteresis loops and first order reversal curves. Extrapolation of simulation sizes to represent a more stochastic bulk-like system will require sampling of various simulations (i.e., with single non-magnetic defect, single magnetic defect, single grain boundary, single dislocation, etc.) with distributions of input parameters. These outputs can then be compared to laboratory magnetic measurements and ultimately to simulate magnetic Barkhausen noise signals.
Kaul, Sandeep P.
2004-09-30T23:59:59.000Z
Spontaneous imbibition plays a very important role in the displacement mechanism of non-wetting fluid in naturally fractured reservoirs. We developed a new 2D two-phase finite element numerical model, as available commercial simulators cannot...
Pielke, Roger A.
-case impacts of power plant plumes on U.S. National Park lands in south Florida is presented based that synoptic baroclinicity, mesoscale thermal circulations, and boundary-layer turbulence can separately of the polluted air. Both a mathematical description and examples of numerical model simulations are used
Mesoscale Simulations of Particulate Flows with Parallel Distributed Lagrange Multiplier Technique
Kanarska, Y
2010-03-24T23:59:59.000Z
Fluid particulate flows are common phenomena in nature and industry. Modeling of such flows at micro and macro levels as well establishing relationships between these approaches are needed to understand properties of the particulate matter. We propose a computational technique based on the direct numerical simulation of the particulate flows. The numerical method is based on the distributed Lagrange multiplier technique following the ideas of Glowinski et al. (1999). Each particle is explicitly resolved on an Eulerian grid as a separate domain, using solid volume fractions. The fluid equations are solved through the entire computational domain, however, Lagrange multiplier constrains are applied inside the particle domain such that the fluid within any volume associated with a solid particle moves as an incompressible rigid body. Mutual forces for the fluid-particle interactions are internal to the system. Particles interact with the fluid via fluid dynamic equations, resulting in implicit fluid-rigid-body coupling relations that produce realistic fluid flow around the particles (i.e., no-slip boundary conditions). The particle-particle interactions are implemented using explicit force-displacement interactions for frictional inelastic particles similar to the DEM method of Cundall et al. (1979) with some modifications using a volume of an overlapping region as an input to the contact forces. The method is flexible enough to handle arbitrary particle shapes and size distributions. A parallel implementation of the method is based on the SAMRAI (Structured Adaptive Mesh Refinement Application Infrastructure) library, which allows handling of large amounts of rigid particles and enables local grid refinement. Accuracy and convergence of the presented method has been tested against known solutions for a falling sphere as well as by examining fluid flows through stationary particle beds (periodic and cubic packing). To evaluate code performance and validate particle contact physics algorithm, we performed simulations of a representative experiment conducted at the University of California at Berkley for pebble flow through a narrow opening.
B-spline finite elements for plane elasticity problems
Aggarwal, Bhavya
2007-04-25T23:59:59.000Z
. The k-refinement is reported to be much more efficient and robust than the standard h or p- refinement used in the conventional FEM models. Besides the use of B-spline functions for structural problems, they have been used in some other fields as well... and convergence behavior. The paper reports a reduction in the numerical cost using B-spline FEM. The use of the B-spline finite element method for the thermistor problem [29,30] and for a numerical solution of Burger?s equation[31- 33] has been successfully...
Current commutator anomalies in finite-element quantum electrodynamics
Dean F. Miller
1993-12-20T23:59:59.000Z
Four-dimensional quantum electrodynamics has been formulated on a hypercubic Minkowski finite-element lattice. The equations of motion have been derived so as to preserve lattice gauge invariance and have been shown to be unitary. In addition, species doubling is avoided due to the nonlocality of the interactions. The model is used to investigate the lattice current algebra. Regularization of the current is shown to arise in a natural and nonarbitrary way. The commutators of the lattice current are calculated and shown to have the expected qualitative behavior. These lattice results are compared to various continuum calculations. (Five figures available from author.)
Conservation Scheme for sigma Ocean Models
Chu, Peter C.
Conservation Scheme for sigma Ocean Models (Finite Volume Consideration for Pressure Gradient Force for the Finite Volume · Flux Conservation #12;Dynamic and Thermodynamic Equations · Continuity · Momentum
The Lagrangian particle dispersion model FLEXPART-WRF VERSION 3.1
Brioude, J.; Arnold, D.; Stohl, A.; Cassiani, M.; Morton, Don; Seibert, P.; Angevine, W. M.; Evan, S.; Dingwell, A.; Fast, Jerome D.; Easter, Richard C.; Pisso, I.; Bukhart, J.; Wotawa, G.
2013-11-01T23:59:59.000Z
The Lagrangian particle dispersion model FLEXPART was originally designed for cal- culating long-range and mesoscale dispersion of air pollutants from point sources, such as after an accident in a nuclear power plant. In the meantime FLEXPART has evolved into a comprehensive tool for atmospheric transport modeling and analysis at different scales. This multiscale need from the modeler community has encouraged new developments in FLEXPART. In this document, we present a version that works with the Weather Research and Forecasting (WRF) mesoscale meteoro- logical model. Simple procedures on how to run FLEXPART-WRF are presented along with special options and features that differ from its predecessor versions. In addition, test case data, the source code and visualization tools are provided to the reader as supplementary material.
Finite-temperature lineshapes in gapped quantum spin chains
Fabian H. L. Essler; Robert M. Konik
2007-12-05T23:59:59.000Z
We consider the finite-temperature dynamical structure factor (DSF) of gapped quantum spin chains such as the spin one Heisenberg model and the transverse field Ising model in the disordered phase. At zero temperature the DSF in these models is dominated by a delta-function line arising from the coherent propagation of single particle modes. Using methods of integrable quantum field theory we determine the evolution of the lineshape at low temperatures. We show that the line shape is in general asymmetric in energy and becomes Lorentzian only at temperatures far below the gap. We discuss the relevance of our results for the analysis of inelastic neutron scattering experiments on gapped spin chain systems such as CsNiCl_3 and YBaNiO_5.
Nonlinear Legendre Spectral Finite Elements for Wind Turbine Blade Dynamics: Preprint
Wang, Q.; Sprague, M. A.; Jonkman, J.; Johnson, N.
2014-01-01T23:59:59.000Z
This paper presents a numerical implementation and examination of new wind turbine blade finite element model based on Geometrically Exact Beam Theory (GEBT) and a high-order spectral finite element method. The displacement-based GEBT is presented, which includes the coupling effects that exist in composite structures and geometric nonlinearity. Legendre spectral finite elements (LSFEs) are high-order finite elements with nodes located at the Gauss-Legendre-Lobatto points. LSFEs can be an order of magnitude more efficient that low-order finite elements for a given accuracy level. Interpolation of the three-dimensional rotation, a major technical barrier in large-deformation simulation, is discussed in the context of LSFEs. It is shown, by numerical example, that the high-order LSFEs, where weak forms are evaluated with nodal quadrature, do not suffer from a drawback that exists in low-order finite elements where the tangent-stiffness matrix is calculated at the Gauss points. Finally, the new LSFE code is implemented in the new FAST Modularization Framework for dynamic simulation of highly flexible composite-material wind turbine blades. The framework allows for fully interactive simulations of turbine blades in operating conditions. Numerical examples showing validation and LSFE performance will be provided in the final paper.
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Modeling Figure 1 shows... by coupling the wing finite element model and the aerodynamic model is based on the unsteady Doublet... - TURKEY STRUCTURAL MODELING AND FLUTTER...
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationClean Communities of WesternVailCloistered JuneLabClosest TypeClosing
Accelerated finite element elastodynamic simulations using the GPU
Huthwaite, Peter, E-mail: p.huthwaite@imperial.ac.uk
2014-01-15T23:59:59.000Z
An approach is developed to perform explicit time domain finite element simulations of elastodynamic problems on the graphical processing unit, using Nvidia's CUDA. Of critical importance for this problem is the arrangement of nodes in memory, allowing data to be loaded efficiently and minimising communication between the independently executed blocks of threads. The initial stage of memory arrangement is partitioning the mesh; both a well established greedy partitioner and a new, more efficient aligned partitioner are investigated. A method is then developed to efficiently arrange the memory within each partition. The software is applied to three models from the fields of non-destructive testing, vibrations and geophysics, demonstrating a memory bandwidth of very close to the card's maximum, reflecting the bandwidth-limited nature of the algorithm. Comparison with Abaqus, a widely used commercial CPU equivalent, validated the accuracy of the results and demonstrated a speed improvement of around two orders of magnitude. A software package, Pogo, incorporating these developments, is released open source, downloadable from (http://www.pogo-fea.com/) to benefit the community. -- Highlights: A novel memory arrangement approach is discussed for finite elements on the GPU. The mesh is partitioned then nodes are arranged efficiently within each partition. Models from ultrasonics, vibrations and geophysics are run. The code is significantly faster than an equivalent commercial CPU package. Pogo, the new software package, is released open source.
Complex saddle points in QCD at finite temperature and density
Hiromichi Nishimura; Michael C. Ogilvie; Kamal Pangeni
2014-08-12T23:59:59.000Z
The sign problem in QCD at finite temperature and density leads naturally to the consideration of complex saddle points of the action or effective action. The global symmetry $\\mathcal{CK}$ of the finite-density action, where $\\mathcal{C}$ is charge conjugation and $\\mathcal{K}$ is complex conjugation, constrains the eigenvalues of the Polyakov loop operator $P$ at a saddle point in such a way that the action is real at a saddle point, and net color charge is zero. The values of $Tr_{F}P$ and $Tr_{F}P^{\\dagger}$ at the saddle point, are real but not identical, indicating the different free energy cost associated with inserting a heavy quark versus an antiquark into the system. At such complex saddle points, the mass matrix associated with Polyakov loops may have complex eigenvalues, reflecting oscillatory behavior in color-charge densities. We illustrate these properties with a simple model which includes the one-loop contribution of gluons and massless quarks moving in a constant Polyakov loop background. Confinement-deconfinement effects are modeled phenomenologically via an added potential term depending on the Polyakov loop eigenvalues. For sufficiently large $T$ and $\\mu$, the results obtained reduce to those of perturbation theory at the complex saddle point. These results may be experimentally relevant for the CBM experiment at FAIR.
SUPPRESSION OF DIELECTRONIC RECOMBINATION DUE TO FINITE DENSITY EFFECTS
Nikolic, D.; Gorczyca, T. W.; Korista, K. T. [Western Michigan University, Kalamazoo, MI (United States); Ferland, G. J. [University of Kentucky, Lexington, KY (United States); Badnell, N. R. [University of Strathclyde, Glasgow (United Kingdom)
2013-05-01T23:59:59.000Z
We have developed a general model for determining density-dependent effective dielectronic recombination (DR) rate coefficients in order to explore finite-density effects on the ionization balance of plasmas. Our model consists of multiplying by a suppression factor those highly-accurate total zero-density DR rate coefficients which have been produced from state-of-the-art theoretical calculations and which have been benchmarked by experiment. The suppression factor is based upon earlier detailed collision-radiative calculations which were made for a wide range of ions at various densities and temperatures, but used a simplified treatment of DR. A general suppression formula is then developed as a function of isoelectronic sequence, charge, density, and temperature. These density-dependent effective DR rate coefficients are then used in the plasma simulation code Cloudy to compute ionization balance curves for both collisionally ionized and photoionized plasmas at very low (n{sub e} = 1 cm{sup -3}) and finite (n{sub e} = 10{sup 10} cm{sup -3}) densities. We find that the denser case is significantly more ionized due to suppression of DR, warranting further studies of density effects on DR by detailed collisional-radiative calculations which utilize state-of-the-art partial DR rate coefficients. This is expected to impact the predictions of the ionization balance in denser cosmic gases such as those found in nova and supernova shells, accretion disks, and the broad emission line regions in active galactic nuclei.
Generalized finite element method for Helmholtz equation
Hidajat, Realino Lulie
2009-05-15T23:59:59.000Z
reduces the pollution effect due to wave number and we are able to obtain a highly accurate solution with a much smaller number of degrees-of-freedom compared with the classical Finite Element Method. The q-convergence of the handbook functions...
Infrared finite coupling in Sudakov resummation
Georges Grunberg
2006-02-06T23:59:59.000Z
New arguments are presented to emphasize the interest of the infrared finite coupling approach to power corrections in the context of Sudakov resummation. The more regular infrared behavior of some peculiar combinations of Sudakov anomalous dimensions, free of Landau singularities at large Nf, is pointed out. A general conflict between the infrared finite coupling and infrared renormalon approaches to power corrections is explained, and a possible resolution is proposed, which makes use of the arbitrariness of the choice of exponentiated constant terms. A simple ansatz for a 'universal' non-perturbative Sudakov effective coupling at large Nf follows naturally from these considerations. In this last version, a new result is presented: the striking emergence of an infrared finite perturbative effective coupling in the Drell-Yan process at large Nf (at odds with the infrared renormalon argument) within the framework of Sudakov resummation for eikonal cross sections of Laenen, Sterman and Vogelsang. Some suggestions for phenomenology at finite Nf, alternative to the shape function approach, are given.
Finite volume renormalization scheme for fermionic operators
Monahan, Christopher; Orginos, Kostas [JLAB
2013-11-01T23:59:59.000Z
We propose a new finite volume renormalization scheme. Our scheme is based on the Gradient Flow applied to both fermion and gauge fields and, much like the Schr\\"odinger functional method, allows for a nonperturbative determination of the scale dependence of operators using a step-scaling approach. We give some preliminary results for the pseudo-scalar density in the quenched approximation.
Tate Cohomology of Finite Dimensional Hopf Algebras
Nguyen, Van Cat
2014-06-19T23:59:59.000Z
Let A be a finite dimensional Hopf algebra over a field k. In this dissertation, we study the Tate cohomology ?* (A, k) and Tate-Hochschild cohomology (HH) ?* (A, A) of A, and their properties. We introduce cup products that make them become graded...
Cavity Field Reconstruction at Finite Temperature
Moya-Cessa, H; Tombesi, P; Roversi, J A
2000-01-01T23:59:59.000Z
We present a scheme to reconstruct the quantum state of a field preparedinside a lossy cavity at finite temperature. Quantum coherences are normallydestroyed by the interaction with an environment, but we show that it ispossible to recover complete information about the initial state (beforeinteraction with its environment), making possible to reconstruct any$s$-parametrized quasiprobability distribution, in particular, the Wignerfunction.
Finitely presented groups 4 Max Neunhffer
Neunhöffer, Max
under rotation and inversion and all r R are reduced. Max Neunhöffer (University of St Andrews.e.: pa, pb R for a, b ^X with a = b. Max Neunhöffer (University of St Andrews) Finitely presented is a piece, we have |p| r|. (|r| is the length in letters). Max Neunhöffer (University of St Andrews
Universitat Regensburg On finite-dimensional motives
Regensburg, Universität - Naturwissenschaftliche Fakultät I
Preprint Nr. 05/2006 #12;On finite-dimensional motives and Murre's conjecture by Uwe Jannsen To Jacob Murre to the existing results (cf. [An1] for a survey) which may be interesting in their own right, but also bear on our
A MIXED FINITE ELEMENT--FINITE VOLUME FORMULATION OF THE BLACKOIL MODEL #
Bergamaschi, Luca
three independent components (oil, gas, and water) form the three phases (liquid, vapor, and aqua. The two chemical components, oil and gas, represent ideal mean hydrocarbons. At standard pressure and temperature (``stocktank'' conditions or STC), the ``oil'' hydrocarbon will be present in the liquid phase
Hong, Jung-Wuk, 1970-
2004-01-01T23:59:59.000Z
In this thesis we develop some advances in the method of finite spheres which is a truly meshless numerical technique for the solution of boundary value problems on geometrically complex domains. We present the development ...
Behera, B; Routray, T R; Centelles, M
2015-01-01T23:59:59.000Z
The properties of spin polarized pure neutron matter and symmetric nuclear matter are studied using the finite range simple effective interaction, upon its parametrization revisited. Out of the total twelve parameters involved, we now determine ten of them from nuclear matter, against the nine parameters in our earlier calculation, as required in order to have predictions in both spin polarized nuclear matter and finite nuclei in unique manner being free from uncertainty found using the earlier parametrization. The information on the effective mass splitting in polarized neutron matter of the microscopic calculations is used to constrain the one more parameter, that was earlier determined from finite nucleus, and in doing so the quality of the description of finite nuclei is not compromised. The interaction with the new set of parameters is used to study the possibilities of ferromagnetic and antiferromagnetic transitions in completely polarized symmetric nuclear matter. Emphasis is given to analyze the resul...
Liquefaction Mapping in Finite-Element Simulations Kirk C. Ellison, S.M.ASCE1
Andrade, Jose
soil liquefaction based on solid mechanical theory rather than empiricism. DOI: 10.1061/ ASCE GT.1943 potentially unstable regions in granular soils at the engineering scale. Example simulations are presented-5606.0000122 CE Database subject headings: Soil liquefaction; Finite element method; Constitutive models
A Two Level Finite Difference Scheme for One Dimensional Pennes' Bioheat Equation \\Lambda
Zhang, Jun
by exposing human body to heat in a flash fire or being in contact with hot substances are some of the most for a skin heating model are conducted. Key words: bioheat transfer, Pennes' equation, finite difference.S. Department of Energy Office of Science under grant DEFG0202ER45961, by the Japanese Research Organization
Combining CSP and ObjectZ: Finite or Infinite Trace Semantics?
Olderog, Ernst-Rüdiger
Combining CSP and ObjectZ: Finite or Infinite Trace Semantics? Clemens Fischer Universit semantics as a means of com bining CSP with ObjectZ. The purpose of this combination is to more effectively specify complex, concurrent systems: while CSP is ideal for modelling systems of concurrent
Fehske, Holger
Laboratory, Los Alamos, New Mexico 87545, USA (Received 11 August 2010; revised manuscript received 17 and polaron transport through finite quantum structures in the framework of the one-dimensional Holstein model a quantum wall or dot is generally accompanied by strong phonon number fluctuations due to phonon emission
A 2D/3D Discrete Duality Finite Volume Scheme. Application to ECG simulation
Paris-Sud XI, Université de
A 2D/3D Discrete Duality Finite Volume Scheme. Application to ECG simulation Y. Coudi`ere Universit-10Oct2008 #12;A 2D/3D DDFV scheme for ECG simulation 1 Introduction Computer models of the electrical-known electrocardiogram (ECG). It gives a non-invasive representation of the cardiac electrical function. Un- derstanding
A 2D/3D Discrete Duality Finite Volume Scheme. Application to ECG simulation
Coudière, Yves
A 2D/3D Discrete Duality Finite Volume Scheme. Application to ECG simulation Y. Coudi`ere Universit for ECG simulation 1 Introduction Computer models of the electrical activity in the myocardium, the measurement of which on the body surface is the well-known electrocardiogram (ECG). It gives a non
Duality in spaces of finite linear combinations of atoms
Ricci, Fulvio
Duality in spaces of finite linear combinations of atoms Fulvio Ricci and Joan Verdera Abstract In this note we describe the dual and the completion of the space of finite linear combinations of (p, )-atoms, )-atoms, 0
Complete Embedded Minimal Surfaces of Finite Total David Hoffman
Complete Embedded Minimal Surfaces of Finite Total Curvature David Hoffman Department-5300 Bonn, Germany July 18, 1994 Contents 1 Introduction 2 2 Basic theory and the global Weierstrass representation 4 2.1 Finite total curvature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2
Radial convection of finite ion temperature, high amplitude plasma blobs
Wiesenberger, M., E-mail: Matthias.Wiesenberger@uibk.ac.at; Kendl, A. [Institute for Ion Physics and Applied Physics, Association EURATOM-AW, University of Innsbruck, A-6020 Innsbruck (Austria); Madsen, J. [Association EURATOM-DTU, Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark)
2014-09-15T23:59:59.000Z
We present results from simulations of seeded blob convection in the scrape-off-layer of magnetically confined fusion plasmas. We consistently incorporate high fluctuation amplitude levels and finite Larmor radius (FLR) effects using a fully nonlinear global gyrofluid model. This is in line with conditions found in tokamak scrape-off-layers (SOL) regions. Varying the ion temperature, the initial blob width, and the initial amplitude, we found an FLR dominated regime where the blob behavior is significantly different from what is predicted by cold-ion models. The transition to this regime is very well described by the ratio of the ion gyroradius to the characteristic gradient scale length of the blob. We compare the global gyrofluid model with a partly linearized local model. For low ion temperatures, we find that simulations of the global model show more coherent blobs with an increased cross-field transport compared to blobs simulated with the local model. The maximal blob amplitude is significantly higher in the global simulations than in the local ones. When the ion temperature is comparable to the electron temperature, global blob simulations show a reduced blob coherence and a decreased cross-field transport in comparison with local blob simulations.
GLOBAL AND FINITE TERMINATION OF A TWO-PHASE ...
2007-06-12T23:59:59.000Z
GLOBAL AND FINITE TERMINATION OF A TWO-PHASE. AUGMENTED LAGRANGIAN FILTER METHOD FOR. GENERAL QUADRATIC PROGRAMS?.
On the Translation of Procedures to Finite Machines
Müller-Olm, Markus
On the Translation of Procedures to Finite Machines Abstraction Allows a Clean Proof Markus M¨uller-Olm
On the Translation of Procedures to Finite Machines
Müller-Olm, Markus
On the Translation of Procedures to Finite Machines Abstraction Allows a Clean Proof Markus M?ullerOlm
Two-flavor QCD phases and condensates at finite isospin chemical potential
Zhao Zhang; Yu-xin Liu
2007-02-06T23:59:59.000Z
We study the phase structure and condensates of two-flavor QCD at finite isospin chemical potential in the framework of a confining, Dyson-Schwinger equation model. We find that the pion superfluidity phase is favored at high enough isospin chemical potential. A new gauge invariant mixed quark-gluon condensate induced by isospin chemical potential is proposed based on Operator Product Expansion. We investigate the sign and magnitude of this new condensate and show that it's an important condensate in QCD sum rules at finite isospin density.
Topology on locally finite metric spaces
Capraro, Valerio
2011-01-01T23:59:59.000Z
The necessity of a theory of General Topology and, most of all, of Algebraic Topology on locally finite metric spaces comes from many areas of research in both Applied and Pure Mathematics: Molecular Biology, Mathematical Chemistry, Computer Science, Topological Graph Theory and Metric Geometry. In this paper we propose the basic notions of such a theory and some applications: we replace the classical notions of continuous function, homeomorphism and homotopic equivalence with the notions of NPP-function, NPP-local-isomorphism and NPP-homotopy (NPP stands for Nearest Point Preserving); we also introduce the notion of NPP-isomorphism. We construct three invariants under NPP-isomorphisms and, in particular, we define the fundamental group of a locally finite metric space. As first applications, we propose the following: motivated by the longstanding question whether there is a purely metric condition which extends the notion of amenability of a group to any metric space, we propose the property SN (Small Neighb...
Casimir friction at zero and finite temperatures
Johan S. Hye; Iver Brevik
2014-03-26T23:59:59.000Z
The Casimir friction problem for dielectric plates that move parallel to each other is treated by assuming one of the plates to be at rest. The other performs a closed loop motion in the longitudinal direction. Therewith by use of energy dissipation the formalism becomes more manageable and transparent than in the conventional setting where uniform sliding motion is assumed from $t=-\\infty$ to $t=+\\infty$. One avoids separating off a reversible interparticle force (independent of friction) from the total force. Moreover, the cases of temperatures $T=0$ and finite $T$ are treated on the same footing. For metal plates we find the friction force to be proportional to $v^3$ at $T=0$ while at finite $T$ it is proportional to $v$ for small $v$ as found earlier. Comparisons with earlier results of Pendry (1997, 2010) and Barton (2011) are made.
Finitely Generated Subnormal Subgroups of GL n (D) Are Central #
Finitely Generated Subnormal Subgroups of GL n (D) Are Central # M. MahdaviHezavehi M. G. Mahmudi is to investigate the structure of finitely generated subnormal subgroups of GL n (D) with n # 1. Assume that n # 2 and N is a normal subgroup of GL n (D). It is shown in [1] that if N is finitely generated, then N
Solving the ANTS Problem with Asynchronous Finite State Machines
Solving the ANTS Problem with Asynchronous Finite State Machines Yuval Emek1 , Tobias Langner2 such that each agent is controlled by an asynchronous (randomized) finite state machine: they possess a constant actions are controlled by a randomized finite state machine (FSM) operating in an asynchronous en
FINITE-FUEL SINGULAR CONTROL WITH DISCRETIONARY STOPPING
Wang, Hui
FINITE-FUEL SINGULAR CONTROL WITH DISCRETIONARY STOPPING IOANNIS KARATZAS DepartmentsG40; Secondary 60J65. Key Words: Singular stochastic control, optimal stopping, finite-fuel We discuss the finite-fuel, singular stochastic control problem of optimally tracking the standard
Interval Finite Element Methods: New Directions Rafi Muhanna1
Kreinovich, Vladik
Interval Finite Element Methods: New Directions Rafi Muhanna1 , Vladik Kreinovich2 , Pavel Sol´in2 advanced numerical methods to tackle these problems, such as finite element methods (FEM). Lately, new advanced version of these methods have appeared, such as hierarchic higher-order finite element methods (hp
Introduction to Finite Element Methods \\Lambda Paul S. Heckbert
Treuille, Adrien
Introduction to Finite Element Methods \\Lambda Paul S. Heckbert Carnegie Mellon University Global be solved numerically. In this chapter we explain some of the basics of the finite element method Illumination course notes, SIGGRAPH '93, Anaheim, Aug. 1993 41 #12; 42 Introduction to Finite Element Methods
Gunn, C.A.; Oberer, R.B.; chiang, L.G.; Ceo, R.N.
2003-01-28T23:59:59.000Z
This paper proposes refinements to the finite source correction factor used in holdup measurements. Specifically it focuses on a more general method to estimate the average detector response for a finite source. This proposed method for the average detector response is based directly on the Generalized Geometry Holdup (GGH) assay method. First, the finite source correction factor as originally proposed is reviewed in this paper. Following this review the GGH assay method is described. Lastly, a new finite area calibration factor based on GGH is then proposed for finite point and line sources. As an alternative to the direct use of the finite arca calibration factor, finite source correction factors are also derived from this calibration factor. This new correction factor can be used in a manner similar to the finite source correction factor as currently implemented.
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.
1 Finite Groups 1.1 Generalities
Sohoni, Milind
1 Finite Groups 1.1 Generalities Let V be a vector space over C , and let GL(V ) denote the group that (#26;; V ) is indecomposable is there is no expression V = W 1 #8;W 2 such that #26;(g)(W i ) #18; W i (#26; #3; ; V #3; ) de#12;ned as #26; #3; (v #3; )(v) = v #3; (#26;(g 1 )(v)). It will be convenient
Solitons with nested structure over finite fields
Fumitaka Yura
2014-05-08T23:59:59.000Z
We propose a solitonic dynamical system over finite fields that may be regarded as an analogue of the box-ball systems. The one-soliton solutions of the system, which have nested structures similar to fractals, are also proved. The solitonic system in this paper is described by polynomials, which seems to be novel. Furthermore, in spite of such complex internal structures, numerical simulations exhibit stable propagations before and after collisions among multiple solitons with preserving their patterns.
Yang-Mills correlators at finite temperature: A perturbative perspective
U. Reinosa; J. Serreau; M. Tissier; N. Wschebor
2014-05-12T23:59:59.000Z
We consider the two-point correlators of Yang-Mills theories at finite temperature in the Landau gauge. We employ a model for the corresponding Yang-Mills correlators based on the inclusion of an effective mass term for gluons. The latter is expected to have its origin in the existence of Gribov copies. One-loop calculations at zero temperature have been shown to agree remarkably well with the corresponding lattice data. We extend on this and perform a one-loop calculation of the Matsubara gluon and ghost two-point correlators at finite temperature. We show that, as in the vacuum, an effective gluon mass accurately captures the dominant infrared physics for the magnetic gluon and ghost propagators. It also reproduces the gross qualitative features of the electric gluon propagator. In particular, we find a slight nonmonotonous behavior of the Debye mass as a function of temperature, however not as pronounced as in existing lattice results. A more quantitative description of the electric sector near the deconfinement phase transition certainly requires another physical ingredient sensitive to the order parameter of the transition.
Efficient finite-time measurements under thermal regimes
Carlos Alexandre Brasil; Leonardo Andreta de Castro; Reginaldo de Jesus Napolitano
2014-07-11T23:59:59.000Z
Contrary to conventional quantum mechanics, which treats measurement as instantaneous, here we explore a model for finite-time measurement. The main two-level system interacts with the measurement apparatus in a Markovian way described by the Lindblad equation, and with an environment, which does not include the measuring apparatus. To analyse the environmental effects on the final density operator, we use the Redfield approach, allowing us to consider a non-Markovian noise. In the present hybrid theory, to trace out the environmental degrees of freedom, we use a previously-developed analytic method based on superoperator algebra and Nakajima-Zwanzig superoperators. Here, we analyse two types of system-environment interaction, phase and amplitude damping, which allows us to conclude that, in general, a finite-time quantum measurement performed during a certain period is more efficient than an instantaneous measurement performed at the end of it, because the rate of change of the populations is attenuated by the system-measurement apparatus interaction.
Edwards, W.R.; Hoyer, E.H.; Thompson, A.C.
1985-10-01T23:59:59.000Z
The first crystal of the Brown-Hower x-ray monochromator of the LBL-EXXON 54 pole wiggler beamline at Stanford Synchrotron Radiation Laboratory (SSRL) is subjected to intense synchrotron radiation. To provide an accurate thermal/structural analysis of the existing monochromator design, a finite element analysis (FEA) was performed. A very high and extremely localized heat flux is incident on the Si (220) crystal. The crystal, which possesses pronouncedly temperature-dependent orthotropic properties, in combination with the localized heat load, make the analysis ideally suited for finite element techniques. Characterization of the incident synchrotron radiation is discussed, followed by a review of the techniques employed in modeling the monochromator and its thermal/structural boundary conditions. The results of the finite element analysis, three-dimensional temperature distributions, surface displacements and slopes, and stresses, in the area of interest, are presented. Lastly, the effects these results have on monochromator output flux and resolution are examined.
Heavy quark scattering and quenching in a QCD medium at finite temperature and chemical potential
Berrehrah, H; Cassing, W; Gossiaux, P B; Aichelin, J
2015-01-01T23:59:59.000Z
The heavy quark collisional scattering on partons of the quark gluon plasma (QGP) is studied in a QCD medium at finite temperature and chemical potential. We evaluate the effects of finite parton masses and widths, finite temperature $T$ and quark chemical potential $\\mu_q$ on the different elastic cross sections for dynamical quasi-particles (on- and off-shell particles in the QGP medium as described by the dynamical quasi-particles model "DQPM") using the leading order Born diagrams. Our results show clearly the decrease of the $qQ$ and $gQ$ total elastic cross sections when the temperature and the quark chemical potential increase. These effects are amplified for finite $\\mu_q$ at temperatures lower than the corresponding critical temperature $T_c (\\mu_q)$. Using these cross sections we, furthermore, estimate the energy loss and longitudinal and transverse momentum transfers of a heavy quark propagating in a finite temperature and chemical potential medium. Accordingly, we have shown that the transport pro...
Solar Electric Generating System II finite element analysis
Dohner, J.L.; Anderson, J.R.
1994-04-01T23:59:59.000Z
On June 2, 1992, Landers` earthquake struck the Solar Electric Generating System II, located in Daggett, California. The 30 megawatt power station, operated by the Daggett Leasing Corporation (DLC), suffered substantial damage due to structural failures in the solar farm. These failures consisted of the separation of sliding joints supporting a distribution of parabolic glass mirrors. At separation, the mirrors fell to the ground and broke. It was the desire of the DLC and the Solar Thermal Design Assistance Center (STDAC) of Sandia National Laboratories (SNL) and to redesign these joints so that, in the event of future quakes, costly breakage will be avoided. To accomplish this task, drawings of collector components were developed by the STDAC, from which a detailed finite element computer model of a solar collector was produced. This nonlinear dynamic model, which consisted of over 8,560 degrees of freedom, underwent model reduction to form a low order nonlinear dynamic model containing only 40 degrees of freedom. This model was then used as a design tool to estimate joint dynamics. Using this design tool, joint configurations were modified, and an acceptable joint redesign determined. The results of this analysis showed that the implementation of metal stops welded to support shafts for the purpose of preventing joint separation is a suitable joint redesign. Moreover, it was found that, for quakes of Landers` magnitude, mirror breakage due to enhanced vibration in the trough assembly is unlikely.
Schlegel, Nicole-Jeanne
2011-01-01T23:59:59.000Z
Jakobshavn I. Rinks Observed Historic Flux (km 3 ice/year)I. Rinks * Outlets fed by the Northeast Greenland Ice StreamRinks, measured in 2000). Figure 3.1: Steady-state (A) topography (m) and (C) ice
The distortion of a uniform flow field due to a finite flat plate
Zull, Lawrence Michael
1970-01-01T23:59:59.000Z
Advantages of the Application of the Complete Navier-Stokes Equations Synopsis II ANALYSIS The Physical Model The Mathematical Model Governing Differential Fquations Initial and Boundary Conditions 10 III METHOD OF SOLUTION 19 General Method... INTRODUCTION Pur ose and Sco e The purpose of this study is to apply numerical methods to solve the exact partial differential equations governing viscous fluid flow past a finite flat plate. The flow condition studied is that of time-dependent, two...
TOPAZ3D. 3-D Finite Element Heat Transfer
Shapiro, A.B. [Lawrence Livermore National Lab., CA (United States)
1992-02-24T23:59:59.000Z
TOPAZ3D is a three-dimensional implicit finite element computer code for heat transfer analysis. TOPAZ3D can be used to solve for the steady-state or transient temperature field on three-dimensional geometries. Material properties may be temperature-dependent and either isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions can be specified including temperature, flux, convection, and radiation. By implementing the user subroutine feature, users can model chemical reaction kinetics and allow for any type of functional representation of boundary conditions and internal heat generation. TOPAZ3D can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in the material surrounding the enclosure. Additional features include thermal contact resistance across an interface, bulk fluids, phase change, and energy balances.
Finite-size scaling in unbiased translocation dynamics
Giovanni Brandani; Fulvio Baldovin; Enzo Orlandini; Attilio L. Stella
2014-02-17T23:59:59.000Z
Finite-size scaling arguments naturally lead us to introduce a coordinate-dependent diffusion coefficient in a Fokker-Planck description of the late stage dynamics of unbiased polymer translocation through a membrane pore. The solution for the probability density function of the chemical coordinate matches the initial-stage subdiffusive regime and takes into account the equilibrium entropic drive. Precise scaling relations connect the subdiffusion exponent to the divergence with the polymer length of the translocation time, and also to the singularity of the probability density function at the absorbing boundaries. Quantitative comparisons with numerical simulation data in $d=2$ strongly support the validity of the model and of the predicted scalings.
The $f_1(1285)$ in finite volume
Li-Sheng Geng; Xiu-Lei Ren; Yu Zhou; Hua-Xing Chen; Eulogio Oset
2015-03-23T23:59:59.000Z
Lattice QCD simulations provide a promising way to disentangle different interpretations of hadronic resonances, which might be of particular relevance to understand the nature of the so-called $XYZ$ particles. Recent studies have shown that in addition to the well-established naive quark model picture, the axial-vector meson $f_1(1285)$ can also be understood as a dynamically generated state built upon the $KK^*$ interaction. In this work, we calculate the energy levels of the $KK^*$ system in the $f_1(1285)$ channel in finite volume using the chiral unitary approach. We propose to calculate the loop function in the dimensional regularization scheme, which is equivalent to the hybrid approach adopted in previous studies. We also study the inverse problem of extracting the bound state information from synthetic lattice QCD data and comment on the difference between our approach and the L{\\" u}scher method.
The $f_1(1285)$ in finite volume
Geng, Li-Sheng; Zhou, Yu; Chen, Hua-Xing; Oset, Eulogio
2015-01-01T23:59:59.000Z
Lattice QCD simulations provide a promising way to disentangle different interpretations of hadronic resonances, which might be of particular relevance to understand the nature of the so-called $XYZ$ particles. Recent studies have shown that in addition to the well-established naive quark model picture, the axial-vector meson $f_1(1285)$ can also be understood as a dynamically generated state built upon the $KK^*$ interaction. In this work, we calculate the energy levels of the $KK^*$ system in the $f_1(1285)$ channel in finite volume using the chiral unitary approach. We propose to calculate the loop function in the dimensional regularization scheme, which is equivalent to the hybrid approach adopted in previous studies. We also study the inverse problem of extracting the bound state information from synthetic lattice QCD data and comment on the difference between our approach and the L{\\" u}scher method.
Finite element analyses of a linear-accelerator electron gun
Iqbal, M., E-mail: muniqbal.chep@pu.edu.pk, E-mail: muniqbal@ihep.ac.cn [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Wasy, A. [Department of Mechanical Engineering, Changwon National University, Changwon 641773 (Korea, Republic of)] [Department of Mechanical Engineering, Changwon National University, Changwon 641773 (Korea, Republic of); Islam, G. U. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan)] [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Zhou, Z. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)
2014-02-15T23:59:59.000Z
Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000?C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator.
Finite quantum dissipation: the challenge of obtaining specific heat
Hnggi, Peter; Talkner, Peter
2008-01-01T23:59:59.000Z
We consider a free particle coupled with finite strength to a bath and investigate the evaluation of its specific heat. A harmonic oscillator bath of Drude type with cutoff frequency omega_D is employed to model an ohmic friction force with dissipation strength gamma. Two scenarios for obtaining specific heat are presented. The first one uses the measurement of the kinetic energy of the free particle while the second one is based on the reduced partition function. Both descriptions yield results which are consistent with the Third Law of thermodynamics. Nevertheless, the two methods produce different results that disagree even in their leading quantum corrections at high temperatures. We also consider the regime where the cutoff frequency is smaller than the friction strength, i.e. omega_D1.
Finite size scaling for quantum criticality using the finite-element method
Edwin Antillon; Birgit Wehefritz-Kaufmann; Sabre Kais
2012-03-08T23:59:59.000Z
Finite size scaling for the Schr\\"{o}dinger equation is a systematic approach to calculate the quantum critical parameters for a given Hamiltonian. This approach has been shown to give very accurate results for critical parameters by using a systematic expansion with global basis-type functions. Recently, the finite element method was shown to be a powerful numerical method for ab initio electronic structure calculations with a variable real-space resolution. In this work, we demonstrate how to obtain quantum critical parameters by combining the finite element method (FEM) with finite size scaling (FSS) using different ab initio approximations and exact formulations. The critical parameters could be atomic nuclear charges, internuclear distances, electron density, disorder, lattice structure, and external fields for stability of atomic, molecular systems and quantum phase transitions of extended systems. To illustrate the effectiveness of this approach we provide detailed calculations of applying FEM to approximate solutions for the two-electron atom with varying nuclear charge; these include Hartree-Fock, density functional theory under the local density approximation, and an "exact"' formulation using FEM. We then use the FSS approach to determine its critical nuclear charge for stability; here, the size of the system is related to the number of elements used in the calculations. Results prove to be in good agreement with previous Slater-basis set calculations and demonstrate that it is possible to combine finite size scaling with the finite-element method by using ab initio calculations to obtain quantum critical parameters. The combined approach provides a promising first-principles approach to describe quantum phase transitions for materials and extended systems.
Gnanadesikan, Anand
by the current generation of Earth System Models. Using satellite-based22 estimate of oxygen consumption 1000 m2 /s. Varying Aredi across a suite24 of Earth System Models yields a broadly consistent result with about 1/3 of these waters39 dropping below 10 M (solid black line, Fig. 1c,d).40 The Earth System Models
Energy spectra of finite temperature superfluid helium-4 turbulence
Kivotides, Demosthenes [Department of Aeronautics, Imperial College London, London SW7 2AZ (United Kingdom)
2014-10-15T23:59:59.000Z
A mesoscopic model of finite temperature superfluid helium-4 based on coupled Langevin-Navier-Stokes dynamics is proposed. Drawing upon scaling arguments and available numerical results, a numerical method for designing well resolved, mesoscopic calculations of finite temperature superfluid turbulence is developed. The application of model and numerical method to the problem of fully developed turbulence decay in helium II, indicates that the spectral structure of normal-fluid and superfluid turbulence is significantly more complex than that of turbulence in simple-fluids. Analysis based on a forced flow of helium-4 at 1.3 K, where viscous dissipation in the normal-fluid is compensated by the Lundgren force, indicate three scaling regimes in the normal-fluid, that include the inertial, low wavenumber, Kolmogorov k{sup ?5/3} regime, a sub-turbulence, low Reynolds number, fluctuating k{sup ?2.2} regime, and an intermediate, viscous k{sup ?6} range that connects the two. The k{sup ?2.2} regime is due to normal-fluid forcing by superfluid vortices at high wavenumbers. There are also three scaling regimes in the superfluid, that include a k{sup ?3} range that corresponds to the growth of superfluid vortex instabilities due to mutual-friction action, and an adjacent, low wavenumber, k{sup ?5/3} regime that emerges during the termination of this growth, as superfluid vortices agglomerate between intense normal-fluid vorticity regions, and weakly polarized bundles are formed. There is also evidence of a high wavenumber k{sup ?1} range that corresponds to the probing of individual-vortex velocity fields. The Kelvin waves cascade (the main dynamical effect in zero temperature superfluids) appears to be damped at the intervortex space scale.
Dynamic analysis of mechanisms by finite elements
Botsali, F.M.; Uenuevar, A. [Selcuk Univ., Konya (Turkey). Mechanical Engineering Dept.
1996-11-01T23:59:59.000Z
The need to increase productivity in order to decrease manufacturing costs lead to an increase in the working speeds of machines and mechanical systems used in manufacturing. A method is presented for investigating the dynamics of mechanisms with elastic links. Finite element method is used in the formulation of the dynamic problem. Modal transformation is used in order to reduce the number of equations of motion. Using the presented technique, elastic and rigid body motions of mechanism links are solved simultaneously. The presented method may be applied to spatial and open loop mechanisms including robot manipulators as well.
Niu, Y. F. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Paar, N.; Vretenar, D. [Physics Department, Faculty of Science, University of Zagreb, Zagreb (Croatia); Meng, J. [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Department of Physics, University of Stellenbosch, Stellenbosch 7602 (South Africa)
2011-04-15T23:59:59.000Z
We introduce a self-consistent microscopic theoretical framework for modeling the process of electron capture on nuclei in stellar environment, based on relativistic energy density functionals. The finite-temperature relativistic mean-field model is used to calculate the single-nucleon basis and the occupation factors in a target nucleus, and J{sup {pi}}=0{sup {+-}}, 1{sup {+-}}, and 2{sup {+-}} charge-exchange transitions are described by the self-consistent finite-temperature relativistic random-phase approximation. Cross sections and rates are calculated for electron capture on {sup 54,56}Fe and {sup 76,78}Ge in stellar environment, and results compared with predictions of similar and complementary model calculations.
One dimensional electroseismic modeling using the finite element ...
2013-01-30T23:59:59.000Z
... and Campanella, O., Characterization of frozen orange juice by ultrasound and wavelet analysis, to appear in Journal of the. Science of Food and Agriculture...
Finite element modeling of SHTE and PSVTM electroseismics
zyserman
(kinetic) energy. The electroseismic equations linking ...... located centered with respect to the x-axis and on the soil surface. The com- putational domain has 3...
Flexible finite-element modeling of global geomagnetic depth sounding
Ribaudo, Joseph Thomas
2011-01-01T23:59:59.000Z
also like to thank Steven Constable, Alexei Kuvshinov, andand Bob Parker and Steven Constable for useful discussions.Randolph E. Bank Steven C. Constable Jeffrey S. Gee Robert
Finite element modeling of SHTE and PSVTM electroseismics
Fabio I. Zyserman
2010-10-07T23:59:59.000Z
Article history: Received 8 January ... partially saturated gas regions are presented. ...... homogeneous layer of water-saturated poorly permeable shale; the.
Finite element modeling of hydraulic fracturing in 3D
2013-03-22T23:59:59.000Z
Mar 22, 2013 ... tion of hydrofracture properties using signals from hydraulic pumps. J. Pet. Sci. ... A.. Touzelet. S.: Tracer testing of the geothermal heat ex-.
Parallel finite element modeling of earthquake ground response and liquefaction
Lu, Jinchi
2006-01-01T23:59:59.000Z
Machines Corporation (IBM). Arduino, P. , Kramer, S. , and2000; Shao and Desai 2000; Arduino et al. 2001). Currently,
Finite element based micromechanical modeling of periodic composite microstructures
Rosario, Matthew J
2010-01-01T23:59:59.000Z
The mechanical behavior of cellular solids, including stiffness and strength, can be tuned by tailoring the underlying geometry and material constituents of the microstructure. Here the effect of key parameters on the ...
Finite-element harmonic experiments to model fractured induced ...
santos
Mar 10, 2014 ... Fractured hydrocarbon reservoirs have been the subject of interest in ...... size. Once a continuous fractal distribution of brine is obtained over...
Finite element modeling of heat and mass transport in aquifers
Grubaugh, Elston Kent
1980-01-01T23:59:59.000Z
1s written as v [ ' ( ? + pg ? )] + 0 = (o + ep a ) ? + ez a ? !I) kxi o ap aT ax, ax; o p at o T at where kx. 1 Po Bp 9T intr1nsic permeab1lity in the x. direct1on, L ; 2. 1 fluid density, M L -2. fluid dynamic v1scos1ty, FTL 2 -l... The basis functions used here are presented in Table 1. These functions fulfill both the compatibility and completeness requirements Linear Nodes le 5r lo Quadratic Nodes 13 I 820 9 I I l7 J Ig ~ I8 l4 19 23 24 Cubic Nodes 37 38 30 39 743...
Finite Difference Modeling of Seismic Responses to Intersecting Fracture Sets
Chi, Shihong
2006-01-01T23:59:59.000Z
Fractured reservoir characterization is becoming increasingly important for the petroleum industry. Currentmethods for this task are developed based on effectivemedia theory, which assumes the cracks or fractures in a ...
A Mixed Finite Element Framework for Modeling Coupled Fluid Flow ...
Birendra Jha
2005-10-03T23:59:59.000Z
such as recovery from compaction drive, waterflooding, surface subsidence, seal in- tegrity ...... and for rocks and concrete it is in the range of 0.4-0.6. ...... incorporate into the programs an automatic, self-adaptive, procedure which adjusts.
R.H. Saunders GS concrete growth mitigation project instrumentation and finite element analysis
Adeghe, L.; Hindy, A.; Ho, M.S. [Hydroelectric Business Unit, Ontario Hydro, Toronto, Ontario (Canada)
1995-12-31T23:59:59.000Z
In 1991, concrete expansion due to Alkali-Silica Reaction (ASR), was diagnosed as the cause of operational and structural problems at R.H. Saunders Generating Station. Reestablishment of contraction joints between the generating units by cutting slots was initiated in January 1993 to relieve accumulated stresses and allow further expansion without deforming the turbine-generators. An integral part of the remedial measure is the installation of an extensive instrumentation system and development of detailed finite element models of the powerhouse structures. In total, two hundred and thirty five instruments have been installed. The instruments include surface extensometers, borehole extensometers, crackmeters, stressmeters, pendulums, thermocouples, borehole convergence meters and strain gauges. All the instruments are monitored continuously by an Automatic Data Acquisition System (ADAS) which allows instrument data to be evaluated remotely. This instrumentation system is being used to collect data on the structural concrete expansion and response to slot cutting. To complement the instrumentation data, three different finite element models have been developed for use. The models range from a very detailed representation of a single powerhouse unit to a less detailed model of the sixteen-unit powerhouse. The finite element models have been calibrated to reflect measured data and subsequently used to estimate the location and frequency of future cuts.
B. Behera; X. Vias; T. R. Routray; M. Centelles
2015-01-12T23:59:59.000Z
The properties of spin polarized pure neutron matter and symmetric nuclear matter are studied using the finite range simple effective interaction, upon its parametrization revisited. Out of the total twelve parameters involved, we now determine ten of them from nuclear matter, against the nine parameters in our earlier calculation, as required in order to have predictions in both spin polarized nuclear matter and finite nuclei in unique manner being free from uncertainty found using the earlier parametrization. The information on the effective mass splitting in polarized neutron matter of the microscopic calculations is used to constrain the one more parameter, that was earlier determined from finite nucleus, and in doing so the quality of the description of finite nuclei is not compromised. The interaction with the new set of parameters is used to study the possibilities of ferromagnetic and antiferromagnetic transitions in completely polarized symmetric nuclear matter. Emphasis is given to analyze the results analytically, as far as possible, to elucidate the role of the interaction parameters involved in the predictions.
LATTICE QCD AT FINITE TEMPERATURE AND DENSITY.
BLUM,T.; CREUTZ,M.; PETRECZKY,P.
2004-02-24T23:59:59.000Z
With the operation of the RHIC heavy ion program, the theoretical understanding of QCD at finite temperature and density has become increasingly important. Though QCD at finite temperature has been extensively studied using lattice Monte-Carlo simulations over the past twenty years, most physical questions relevant for RHIC (and future) heavy ion experiments remain open. In lattice QCD at finite temperature and density there have been at least two major advances in recent years. First, for the first time calculations of real time quantities, like meson spectral functions have become available. Second, the lattice study of the QCD phase diagram and equation of state have been extended to finite baryon density by several groups. Both issues were extensively discussed in the course of the workshop. A real highlight was the study of the QCD phase diagram in (T, {mu})-plane by Z. Fodor and S. Katz and the determination of the critical end-point for the physical value of the pion mass. This was the first time such lattice calculations at, the physical pion mass have been performed. Results by Z Fodor and S. Katz were obtained using a multi-parameter re-weighting method. Other determinations of the critical end point were also presented, in particular using a Taylor expansion around {mu} = 0 (Bielefeld group, Ejiri et al.) and using analytic continuation from imaginary chemical potential (Ph. de Forcrand and O. Philipsen). The result based on Taylor expansion agrees within errors with the new prediction of Z. Fodor and S. Katz, while methods based on analytic continuation still predict a higher value for the critical baryon density. Most of the thermodynamics studies in full QCD (including those presented at this workshop) have been performed using quite coarse lattices, a = 0.2-0.3 fm. Therefore one may worry about cutoff effects in different thermodynamic quantities, like the transition temperature T{sub tr}. At the workshop U. Heller presented a study of the transition temperature for three different lattice spacings and performed a continuum extrapolation of T{sub tr} for the first time. Lattice calculations of the meson spectral functions were presented by M. Asakawa, S. Datta, E. Laermann and H. Matsufuru. These show that charmonia ground states ({eta}{sub c} and J/{psi}) continue to exist in the plasma at least up to a temperature of 1.7 T{sub tr}. At what temperature charmonia states cease to exist is not yet clear. Calculations presented by M. Asakawa show dissolution of the J/{psi} at T = 1.7 T{sub tr}, while the analysis presented H. Matsufuru provided evidence that ground state charmonia still exist at this temperature. S. Datta argued that the ground state charmonia is likely to dissolve only for temperatures T > 2.25 T{sub tr}, while the P-states are dissociated at, 1.1 T{sub tr}. It is also very interesting that, even in the case of light quarks, meson spectral functions show a resonance-like structure in the plasma phase (talk by E. Laermann). Finally attempts to calculate transport properties in the Quark Gluon Plasma were presented by S. Gupta. The workshop devoted special attention to the finite temperature modification of inter-quark forces and color screening, another area where considerable progress has been made in recent years (talks by 0. Kaczmarek, K. Petrov, O. Philipsen and F. Zantow). Many other new theoretical developments which cannot be discussed here were also presented on the workshop. Altogether the workshop was a great success, for which we thank all the participants.
Quarkonium Dissociation at Finite Chemical Potential
Kakade, Uttam
2015-01-01T23:59:59.000Z
We have studied the dissociation of quarkonia states in a deconfined medium of quarks and gluons at large baryon chemical potential and small temperature region. The aim of this study is to probe the dense baryonic medium expected to be produced at FAIR facility, GSI Darmstadt. This is done by correcting both the short and long-distance terms of the Cornell potential by a dielectric function, embodying the effects of deconfined quarks and gluons, at finite baryon chemical potential and temperature. It is found that $J/\\psi$ is dissociated approximately at 2 $\\mu_c$ in the temperature range 20-50 MeV, which can indirectly help to locate the point on QCD phase diagram at large chemical potential and low temperature zone.
On perfect order subsets in finite groups
Tuan, Nguyen Trong
2010-01-01T23:59:59.000Z
If $G$ is a finite group and $x\\in G$ then the set of all elements of $G$ having the same order as $x$ is called {\\em an order subset of $G$ determined by $x$} (see [2]). We say that $G$ is a {\\em group with perfect order subsets} or briefly, $G$ is a {\\em $POS$-group} if the number of elements in each order subset of $G$ is a divisor of $|G|$. In this paper we prove that for any $n\\geq 4$, the symmetric group $S_n$ is not $POS$-group. This gives the positive answer to one of two questions rising from Conjecture 5.2 in [3].
Light front Casimir effect at finite temperature
Rodrigues, P L M; Alves, Danilo T; Alves, Van Srgio; Silva, Charles R
2015-01-01T23:59:59.000Z
The correct description of the standard Casimir effect for periodic boundary conditions via light front formalism implies in these conditions imposed at fixed Minkowski times [Almeida {\\it et al.} Phys. Rev. {\\bf D 87}, 065028 (2013); Chabysheva and Hiller, Phys. Rev. {\\bf D 88}, 085006 (2013)] instead of fixed light front times. The unphysical nature of this latter condition is manifested in the vacuum part by no regularization yielding a finite Casimir energy density [Lenz and Steinbacher, Phys. Rev. {\\bf D 67}, 045010 (2003)]. In the present paper, we extend this discussion and analyze the problem of the light front quantization with simultaneous presence of a thermal bath and boundary conditions. Considering both the oblique light front as well as Dirac light front coordinates, we show that the imposition of periodic boundary conditions at fixed Minkowski times recovers the expected behaviors for the energy density and Casimir entropy. We also investigate how the unphysical nature of the periodic boundary...
BCS Instability and Finite Temperature Corrections to Tachyon Mass in Intersecting D1-Branes
Sudipto Paul Chowdhury; Swarnendu Sarkar; B. Sathiapalan
2014-09-12T23:59:59.000Z
A holographic description of BCS superconductivity is given in arxiv:1104.2843. This model was constructed by insertion of a pair of D8-branes on a D4-background. The spectrum of intersecting D8-branes has tachyonic modes indicating an instability which is identified with the BCS instability in superconductors. Our aim is to study the stability of the intersecting branes under finite temperature effects. Many of the technical aspects of this problem are captured by a simpler problem of two intersecting D1-branes on flat background. In the simplified set-up we compute the one-loop finite temperature corrections to the tree-level tachyon mass using the frame-work of SU(2) Yang-Mills theory in (1 + 1)-dimensions. We show that the one-loop two-point functions are ultraviolet finite due to cancellation of ultraviolet divergence between the amplitudes containing bosons and fermions in the loop. The amplitudes are found to be infrared divergent due to the presence of massless fields in the loops. We compute the finite temperature mass correction to all the massless fields and use these temperature dependent masses to compute the tachyonic mass correction. We show numerically the existence of a transition temperature at which the effective mass of the tree-level tachyons becomes zero, thereby stabilizing the brane configuration.
Felice, Maria V. [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, United Kingdom and Rolls-Royce plc., Bristol BS34 7QE (United Kingdom); Velichko, Alexander; Wilcox, Paul D. [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR (United Kingdom); Barden, Tim J.; Dunhill, Tony K. [Rolls-Royce plc., Bristol BS34 7QE (United Kingdom)
2014-02-18T23:59:59.000Z
A hybrid model to simulate the ultrasonic array response from stress corrosion cracks is presented. These cracks are branched and difficult to detect so the model is required to enable optimization of an array design. An efficient frequency-domain finite element method is described and selected to simulate the ultrasonic scattering. Experimental validation results are presented, followed by an example of the simulated ultrasonic array response from a real stress corrosion crack whose geometry is obtained from an X-ray Computed Tomography image. A simulation-assisted array design methodology, which includes the model and use of real crack geometries, is proposed.
R. Ogul; A. S. Botvina
2002-10-15T23:59:59.000Z
The fragment production in multifragmentation of finite nuclei is affected by the critical temperature of nuclear matter. We show that this temperature can be determined on the basis of the statistical multifragmentation model (SMM) by analyzing the evolution of fragment distributions with the excitation energy. This method can reveal a decrease of the critical temperature that, e.g., is expected for neutron-rich matter. The influence of isospin on fragment distributions is also discussed.
QCD phase diagram at finite baryon and isospin chemical potentials
Sasaki, Takahiro; Sakai, Yuji; Yahiro, Masanobu [Department of Physics, Graduate School of Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Kouno, Hiroaki [Department of Physics, Saga University, Saga 840-8502 (Japan)
2010-12-01T23:59:59.000Z
The phase structure of two-flavor QCD is explored for thermal systems with finite baryon- and isospin-chemical potentials, {mu}{sub B} and {mu}{sub iso}, by using the Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model. The PNJL model with the scalar-type eight-quark interaction can reproduce lattice QCD data at not only {mu}{sub iso}={mu}{sub B}=0, but also {mu}{sub iso}>0 and {mu}{sub B}=0. In the {mu}{sub iso}-{mu}{sub B}-T space, where T is temperature, the critical endpoint of the chiral phase transition in the {mu}{sub B}-T plane at {mu}{sub iso}=0 moves to the tricritical point of the pion-superfluidity phase transition in the {mu}{sub iso}-T plane at {mu}{sub B}=0 as {mu}{sub iso} increases. The thermodynamics at small T is controlled by {radical}({sigma}{sup 2}+{pi}{sup 2}) defined by the chiral and pion condensates, {sigma} and {pi}.
Finiteness of the universe and computation beyond Turing computability
Tien D. Kieu
2004-03-16T23:59:59.000Z
We clarify the confusion, misunderstanding and misconception that the physical finiteness of the universe, if the universe is indeed finite, would rule out all hypercomputation, the kind of computation that exceeds the Turing computability, while maintaining and defending the validity of Turing computation and the Church-Turing thesis.
Finite time analysis of an endoreversible fuel cell A. Vaudrey
Paris-Sud XI, Universit de
Finite time analysis of an endoreversible fuel cell A. Vaudrey , P. Baucour, F. Lanzetta, R of this paper consists in a detailed thermodynamical description of a fuel cell, using finite time thermodynamics (FTT). Starting from the comparison beetween a reversible fuel cell and a Carnot heat engine
Muller's ratchet clicks in finite time Julien Audiffren, Etienne Pardoux
Paris-Sud XI, Universit de
Muller's ratchet clicks in finite time Julien Audiffren, Etienne Pardoux Abstract We consider the accumulation of deleterious mutations in an asexual pop- ulation, a phenomenon known as Muller's ratchet, using, the ratchet clicks a.s. in finite time. That is to say the minimum number of deleterious mutations
Duality in spaces of finite linear combinations of atoms
Verdera, Joan
Duality in spaces of finite linear combinations of atoms Fulvio Ricci and Joan Verdera Abstract In this note we describe the dual and the completion of the space of finite linear combinations of (p, #)atoms, #)atoms, 0
Infinite Hamilton Cycles in Squares of Locally Finite Graphs
Diestel, Reinhard
Infinite Hamilton Cycles in Squares of Locally Finite Graphs Agelos Georgakopoulos Abstract We prove Diestel's conjecture that the square G2 of a 2-connected locally finite graph G has a Hamilton if and only if they have distance at most n in G. A Hamilton cycle in a graph is a cycle containing all its
Curved finite elements by the method of initial strains
Leick, Roger Dale
1974-01-01T23:59:59.000Z
, pp. 383-432. 2. Clough, R. W. , "Comparison of Three Dimensional Finite Elements, " Proceedin s of the S osium on A lication of Finite Element Mhd l. t''i~Et f, Vd6'ltUt ty, 1969, pp. 1-26. 3. Stricklin, J. A. , informal proposal submitted to Dr...
Finite-Horizon Optimal Transmission Policies for Energy Harvesting Sensors
Jagannathan, Krishna
Finite-Horizon Optimal Transmission Policies for Energy Harvesting Sensors Rahul Vaze School: krishnaj@ee.iitm.ac.in Abstract--In this paper, we derive optimal transmission poli- cies for energy harvesting sensors to maximize the utility obtained over a finite horizon. First, we consider a single energy
Electromagnetic source localization with finite set of frequency measurements
Abdul Wahab; Amer Rasheed; Rab Nawaz; Saman Anjum
2014-09-16T23:59:59.000Z
A phase conjugation algorithm for localizing an extended radiating electromagnetic source from boundary measurements of the electric field is presented. Measurements are taken over a finite number of frequencies. The artifacts related to the finite frequency data are tackled with $l_1-$regularization blended with the fast iterative shrinkage-thresholding algorithm with backtracking of Beck & Teboulle.
NON-CLOSED CURVES IN Rn WITH FINITE TOTAL FIRST
Gilkey, Peter B
], and Kondo and Tanaka [14] have examined the global properties of the total curvature of a curveNON-CLOSED CURVES IN Rn WITH FINITE TOTAL FIRST CURVATURE ARISING FROM THE SOLUTIONS OF AN ODE P finite total first curvature. If all the roots of the associated characteristic polynomial are simple, we
Hybrid Systems with Finite Bisimulations Gerardo Lafferriere1
Pappas, George J.
Hybrid Systems with Finite Bisimulations Gerardo Lafferriere1 , George J. Pappas2 , and Shankar is one of the main approach- es to hybrid system analysis. Decidability questions for verification algo classes of planar hybrid systems. 1 Introduction Hybrid systems consist of finite state machines
Finite anticanonical transformations in field-antifield formalism
Batalin, Igor A; Tyutin, Igor V
2015-01-01T23:59:59.000Z
We study the role of arbitrary (finite) anticanonical transformations in the field-antifield formalism, and the gauge-fixing procedure based on the use of these transformations. Properties of generating functionals of Green functions subjected to finite anticanonical transformations are considered.
Finite anticanonical transformations in field-antifield formalism
Igor A. Batalin; Peter M. Lavrov; Igor V. Tyutin
2015-01-29T23:59:59.000Z
We study the role of arbitrary (finite) anticanonical transformations in the field-antifield formalism, and the gauge-fixing procedure based on the use of these transformations. Properties of generating functionals of Green functions subjected to finite anticanonical transformations are considered.
Parallel Finite Element Simulation of Tracer Injection in Oil Reservoirs
Coutinho, Alvaro L. G. A.
Parallel Finite Element Simulation of Tracer Injection in Oil Reservoirs Alvaro L.G.A. Coutinho In this work, parallel finite element techniques for the simulation of tracer injection in oil reservoirs. Supercomputers have made it possible to consider global reservoir effects which can not be represented using
Glover, David M.
.S. JGOFS Bermuda Atlantic Time-Series Study (BATS) site David M. Glover Woods Hole Oceanographic that climate scale variability needs to be carefully removed to isolate the eddy signature. #12;2 Glover et al dynamics, model errors and unresolved three-dimensional effects [Glover and Doney, 1996; Glover et al
An h-adaptive finite element method for turbulent heat transfer
Carriington, David B [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
A two-equation turbulence closure model (k-{omega}) using an h-adaptive grid technique and finite element method (FEM) has been developed to simulate low Mach flow and heat transfer. These flows are applicable to many flows in engineering and environmental sciences. Of particular interest in the engineering modeling areas are: combustion, solidification, and heat exchanger design. Flows for indoor air quality modeling and atmospheric pollution transport are typical types of environmental flows modeled with this method. The numerical method is based on a hybrid finite element model using an equal-order projection process. The model includes thermal and species transport, localized mesh refinement (h-adaptive) and Petrov-Galerkin weighting for the stabilizing the advection. This work develops the continuum model of a two-equation turbulence closure method. The fractional step solution method is stated along with the h-adaptive grid method (Carrington and Pepper, 2002). Solutions are presented for 2d flow over a backward-facing step.
Kais, Sabre
initio approximations and exact formulations. The critical parameters could be atomic nuclear charges, and an "exact" formulation using FEM. We then use the FSS approach to determine its critical nuclear chargePHYSICAL REVIEW E 85, 036706 (2012) Finite-size scaling for quantum criticality using the finite
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an implementation of a single-fluid inter- face model in the ALE-AMR code to simulate surface tension effects. The model does not require explicit information on the physical...
Light front Casimir effect at finite temperature
P. L. M. Rodrigues; Silvana Perez; Danilo T. Alves; Van Srgio Alves; Charles R. Silva
2015-01-06T23:59:59.000Z
The correct description of the standard Casimir effect for periodic boundary conditions via light front formalism implies in these conditions imposed at fixed Minkowski times [Almeida {\\it et al.} Phys. Rev. {\\bf D 87}, 065028 (2013); Chabysheva and Hiller, Phys. Rev. {\\bf D 88}, 085006 (2013)] instead of fixed light front times. The unphysical nature of this latter condition is manifested in the vacuum part by no regularization yielding a finite Casimir energy density [Lenz and Steinbacher, Phys. Rev. {\\bf D 67}, 045010 (2003)]. In the present paper, we extend this discussion and analyze the problem of the light front quantization with simultaneous presence of a thermal bath and boundary conditions. Considering both the oblique light front as well as Dirac light front coordinates, we show that the imposition of periodic boundary conditions at fixed Minkowski times recovers the expected behaviors for the energy density and Casimir entropy. We also investigate how the unphysical nature of the periodic boundary conditions imposed at fixed light front times manifests in the thermal part of the energy and entropy, showing that in the classical limit the Casimir entropy decreases linearly with the temperature (not becoming independent of the temperature as expected), and also that the Kirchhoff theorem is not respected.
RSL: A parallel Runtime System Library for regional atmospheric models with nesting
Michalakes, J.G.
1997-08-01T23:59:59.000Z
RSL is a parallel runtime system library developed at Argonne National Laboratory that is tailored to regular-grid atmospheric models with mesh refinement in the form of two-way interacting nested grids. RSL provides high-level stencil and interdomain communication, irregular domain decomposition, automatic local/global index translation, distributed I/O, and dynamic load balancing. RSL was used with Fortran90 to parallelize a well-known and widely used regional weather model, the Penn State/NCAR Mesoscale model.
Modeling a solar energy collector with an integrated phase-change material
Guerra, Alexander Adrian
2009-01-01T23:59:59.000Z
In this thesis, a finite-element computer model was created to simulate a solar air heater with an integrated-phase change material. The commercially available finite element package ADINA-Fluid was used to generate the ...
Infrared nullification of the effective electromagnetic field at finite temperature
Kirill A. Kazakov; Vladimir V. Nikitin
2009-10-30T23:59:59.000Z
The problem of infrared divergence of the effective electromagnetic field at finite temperature (T) is revisited. A model of single spatially localized electron interacting with thermal photons is considered in the limit T to 0 using two different regularization schemes. The first is based on the shift i 0 to i varepsilon of the electron propagator pole in the complex energy plane, and is used to explicitly calculate the effective field in the one-loop approximation. We show that the matrix-valued imaginary part of the electron self-energy can be consistently related to the pole shift, and that the presence of the heat bath leads to appearance of an effective varepsilon sim T, thus providing a natural infrared regulator of the theory. We find that the one-loop effective Coulomb field calculated using this varepsilon vanishes. The other scheme combines an infrared momentum cutoff with smearing of the delta-functions in the interaction vertices. We prove that this regularization admits factorization of the infrared contributions in multi-loop diagrams, and sum the corresponding infinite series. The effective electromagnetic field is found to vanish in this case too. An essentially perturbative nature of this result is emphasized and discussed in connection with the long-range expansion of the effective field.
Finite quantum dissipation: the challenge of obtaining specific heat
Peter Hnggi; Gert-Ludwig Ingold; Peter Talkner
2008-05-26T23:59:59.000Z
We consider a free particle coupled with finite strength to a bath and investigate the evaluation of its specific heat. A harmonic oscillator bath of Drude type with cutoff frequency omega_D is employed to model an ohmic friction force with dissipation strength gamma. Two scenarios for obtaining specific heat are presented. The first one uses the measurement of the kinetic energy of the free particle while the second one is based on the reduced partition function. Both descriptions yield results which are consistent with the Third Law of thermodynamics. Nevertheless, the two methods produce different results that disagree even in their leading quantum corrections at high temperatures. We also consider the regime where the cutoff frequency is smaller than the friction strength, i.e. omega_Dheat based on the thermodynamic prescription becomes negative. This anomaly is rooted in an ill-defined density of states of the damped free particle which assumes unphysical negative values when gamma/omega_D>1.
Equation of state and QCD transition at finite temperature
Bazavov, A; Bhattacharya, T; Cheng, M; Christ, N H; DeTar, C; Ejiri, S; Gottlieb, S; Gupta, R; Heller, U M; Huebner, K; Jung, C; Karsch, F; Laermann, E; Levkova, L; Miao, C; Mawhinney, R D; Petreczky, P; Schmidt, C; Soltz, R A; Soeldner, W; Sugar, R; Toussaint, D; Vranas, P
2009-03-25T23:59:59.000Z
We calculate the equation of state in 2+1 flavor QCD at finite temperature with physical strange quark mass and almost physical light quark masses using lattices with temporal extent N{sub {tau}} = 8. Calculations have been performed with two different improved staggered fermion actions, the asqtad and p4 actions. Overall, we find good agreement between results obtained with these two O(a{sup 2}) improved staggered fermion discretization schemes. A comparison with earlier calculations on coarser lattices is performed to quantify systematic errors in current studies of the equation of state. We also present results for observables that are sensitive to deconfining and chiral aspects of the QCD transition on N{sub {tau}} = 6 and 8 lattices. We find that deconfinement and chiral symmetry restoration happen in the same narrow temperature interval. In an Appendix we present a simple parametrization of the equation of state that can easily be used in hydrodynamic model calculations. In this parametrization we also incorporated an estimate of current uncertainties in the lattice calculations which arise from cutoff and quark mass effects. We estimate these systematic effects to be about 10 MeV.
Reis, A. C.; Moreira Filho, L. A. [ITA - Aeronautic Technological Institute, IEM, Praca Mal. Eduardo Gomes, 50 - Vila das Acacias - S. J. Campos, CEP 1228-900 (Brazil); Menezes, M. A. [ITA - Aeronautic Technological Institute, IEM, Praca Mal. Eduardo Gomes, 50 - Vila das Acacias - S. J. Campos, CEP 1228-900 (Brazil); UNESP - Sao Paulo State University, Ilha Solteira Engineering Faculty, DEM, Av. Brasil, 56 - Centro - Ilha Solteira - SP, CEP 15385-000 (Brazil)
2007-04-07T23:59:59.000Z
The aim of this paper consists in presenting a method of simulating the warpage in 7xxx series aluminium alloy plates. To perform this simulation finite element software MSC.Patran and MSC.Marc were used. Another result of this analysis will be the influence on material residual stresses induced on the raw material during the rolling process upon the warpage of primary aeronautic parts, fabricated through machining (milling) at Embraer. The method used to determinate the aluminium plate residual stress was Layer Removal Test. The numerical algorithm Modified Flavenot Method was used to convert layer removal and beam deflection in stress level. With such information about the level and profile of residual stresses become possible, during the step that anticipate the manufacturing to incorporate these values in the finite-element approach for modelling warpage parts. Based on that warpage parameter surely the products are manufactured with low relative vulnerability propitiating competitiveness and price.
Spin Squeezing in Finite Temperature Bose-Einstein Condensates : Scaling with the system size
Alice Sinatra; Emilia Witkowska; Yvan Castin
2012-05-02T23:59:59.000Z
We perform a multimode treatment of spin squeezing induced by interactions in atomic condensates, and we show that, at finite temperature, the maximum spin squeezing has a finite limit when the atom number $N\\to \\infty$ at fixed density and interaction strength. To calculate the limit of the squeezing parameter for a spatially homogeneous system we perform a double expansion with two small parameters: 1/N in the thermodynamic limit and the non-condensed fraction $/N$ in the Bogoliubov limit. To test our analytical results beyond the Bogoliubov approximation, and to perform numerical experiments, we use improved classical field simulations with a carefully chosen cut-off, such that the classical field model gives for the ideal Bose gas the correct non-condensed fraction in the Bose-condensed regime.
Attraction of Meso-Scale Objects on the Surface of a Thin Elastic Film Supported on a Liquid
Aditi Chakrabarti; Manoj K. Chaudhury
2014-08-07T23:59:59.000Z
We study the interaction of two parallel rigid cylinders on the surface of a thin elastic film supported on a pool of liquid. The excess energy of the surface due to the curvature of the stretched film induces attraction of the cylinders that can be quantified by the variation of their gravitational potential energies as they descend into the liquid while still floating on the film. Although the experimental results follow the trend predicted from the balance of the gravitational and elastic energies of the system, they are somewhat underestimated. The origin of this discrepancy is the hysteresis of adhesion between the cylinder and the elastic film that does not allow the conversion of the total available energy into gravitational potential energy as some part of it is recovered in stretching the film behind the cylinders while they approach each other. A modification of the model accounting for the effects of adhesion hysteresis improves the agreement between theoretical and experimental results. The contribution of the adhesion hysteresis can be reduced considerably by introducing a thin hydrogel layer atop the elastic film that enhances the range of attraction of the cylinders (as well as rigid spheres) in a dramatic way. Morphological instabilities in the gel project corrugated paths to the motion of small spheres, thus leading to a large numbers of particles to aggregate along their defects. These observations suggest that a thin hydrogel layer supported on a deformable elastic film affords an effective model system to study elasticity and defects mediated interaction of particles on its surface.
Daniels, Megan Hanako
2010-01-01T23:59:59.000Z
74 ii Soil Moisture Sensors: Decagon ECH2O Capacitance133 A.10 Soil types corresponding to each75 Soil Moisture and Temperature Probe
Daniels, Megan Hanako
2010-01-01T23:59:59.000Z
red indicates water towers generated by kinematic wavethe kinematic wave equation will begin to collect water onred indicates water towers generated by kinematic wave
Grujicic, Mica
) and for the vehicle-armor systems (e.g. as reinforce- ments in rigid polymer matrix composites, PMCs, for lightweight. Replacement of metal with a nylon (poly- amide) fabric and an E-glass fiber/ethyl cellulose composite in body the ballistic performance of the body-armor vests relative to up to 0.30 caliber threats, ceramic insert strike
Hall, Sharon J.
and latent heat fluxes and therefore the ground temperature, Tg. Evaporation, E, for each grid cell temperature and heat fluxes in the Phoenix metropolitan area. S. Grossman-Clarke1, J.A. Zehnder2, and W) satellite images [2]. The data were upscaled to a 30-second grid and used to augment and correct
Daniels, Megan Hanako
2010-01-01T23:59:59.000Z
direction, (b) wind speed, (c) potential temperature, and (Airport of potential temperature, wind speed, winderrors (bias) for potential temperature, wind speed, wind
E-Print Network 3.0 - anisotropic finite-frequency sensitivity...
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to study the finite-frequency sensitivity to anisotropic parameters... will see later. Smith et al. (2004) introduce 2-D anisotropic sensitivity kernels for finite-frequency......
Modeling-Computer Simulations At Long Valley Caldera Geothermal...
of a rock matrix with finite hydraulic conductivity cut by a steeply dipping fracture with infinite hydraulic conductivity. For this model to match the pressure data the...
Representing Cloud Processing of Aerosol in Numerical Models
Mechem, D.B.; Kogan, Y.L.
2005-03-18T23:59:59.000Z
The satellite imagery in Figure 1 provides dramatic examples of how aerosol influences the cloud field. Aerosol from ship exhaust can serve as nucleation centers in otherwise cloud-free regions, forming ship tracks (top image), or can enhance the reflectance/albedo in already cloudy regions. This image is a demonstration of the first indirect effect, in which changes in aerosol modulate cloud droplet radius and concentration, which influences albedo. It is thought that, through the effects it has on precipitation (drizzle), aerosol can also affect the structure and persistence of planetary boundary layer (PBL) clouds. Regions of cellular convection, or open pockets of cloudiness (bottom image) are thought to be remnants of strongly drizzling PBL clouds. Pockets of Open Cloudiness (POCs) (Stevens et al. 2005) or Albrecht's ''rifts'' are low cloud fraction regions characterized by anomalously low aerosol concentrations, implying they result from precipitation. These features may in fact be a demonstration of the second indirect effect. To accurately represent these clouds in numerical models, we have to treat the coupled cloud-aerosol system. We present the following series of mesoscale and large eddy simulation (LES) experiments to evaluate the important aspects of treating the coupled cloud-aerosol problem. 1. Drizzling and nondrizzling simulations demonstrate the effect of drizzle on a mesoscale forecast off the California coast. 2. LES experiments with explicit (bin) microphysics gauge the relative importance of the shape of the aerosol spectrum on the 3D dynamics and cloud structure. 3. Idealized mesoscale model simulations evaluate the relative roles of various processes, sources, and sinks.
Shell structure and orbit bifurcations in finite fermion systems
A. G. Magner; I. S. Yatsyshyn; K. Arita; M. Brack
2010-12-07T23:59:59.000Z
We first give an overview of the shell-correction method which was developed by V. M. Strutinsky as a practicable and efficient approximation to the general selfconsistent theory of finite fermion systems suggested by A. B. Migdal and collaborators. Then we present in more detail a semiclassical theory of shell effects, also developed by Strutinsky following original ideas of M. Gutzwiller. We emphasize, in particular, the influence of orbit bifurcations on shell structure. We first give a short overview of semiclassical trace formulae, which connect the shell oscillations of a quantum system with a sum over periodic orbits of the corresponding classical system, in what is usually called the "periodic orbit theory". We then present a case study in which the gross features of a typical double-humped nuclear fission barrier, including the effects of mass asymmetry, can be obtained in terms of the shortest periodic orbits of a cavity model with realistic deformations relevant for nuclear fission. Next we investigate shell structures in a spheroidal cavity model which is integrable and allows for far-going analytical computation. We show, in particular, how period-doubling bifurcations are closely connected to the existence of the so-called "superdeformed" energy minimum which corresponds to the fission isomer of actinide nuclei. Finally, we present a general class of radial power-law potentials which approximate well the shape of a Woods-Saxon potential in the bound region, give analytical trace formulae for it and discuss various limits (including the harmonic oscillator and the spherical box potentials).
Transactions of NAMRI/SME FINITE ELEMENT SIMULATION OF
Ozel, Tugrul
Transactions of NAMRI/SME FINITE ELEMENT SIMULATION OF Ti-6Al-4V ALLOY Turul Manufacturing #12;Transactions of NAMRI/SME 50 Volume 38, 2010 excessive heat generation. Usually above 120 m
Torsion cohomology for solvable groups of finite rank.
Karl Lorensen
We define a class $\\mathcal{U}$ of solvable groups of finite abelian section rank which includes all such groups that are virtually torsion-free as well as those that are finitely generated. Assume that $G$ is a group in $\\mathcal{U}$ and $A$ a $\\mathbb ZG$-module. If $A$ is $\\mathbb Z$-torsion-free and has finite $\\mathbb Z$-rank, we stipulate a condition on $A$ that guarantees that $H^n(G,A)$ and $H_n(G,A)$ must be finite for $n\\geq 0$. Moreover, if the underlying abelian group of $A$ is a ?ernikov group, we identify a similar condition on $A$ that ensures that $H^n(G,A)$ must be a ?ernikov group for all $n\\geq 0$.
Characters and finite Frobenius rings Jay A. Wood
Wood, Jay
Characters and finite Frobenius rings Jay A. Wood Department of Mathematics Western Michigan-modules; 3. R = R as right R-modules. Due independently to Hirano, 1997, and Wood, 1999. JW (WMU) Frobenius
FINITE FRACTURE MECHANICS OF MATRIX MICROCRACKING IN COMPOSITES
Nairn, John A.
FINITE FRACTURE MECHANICS OF MATRIX MICROCRACKING IN COMPOSITES JOHN A. NAIRN INTRODUCTION damage following complex loading conditions. This chapter describes a fracture mechanics approach to the microcracking problem. A complicating feature of composite fracture mechanics analysis is that laminates often
Finite generation and continuity of topological Hochschild and cyclic homology.
Bjrn Ian Dundas; Matthew Morrow
The goal of this paper is to establish fundamental properties of the Hochschild, topological Hochschild, and topological cyclic homologies of commutative, Noetherian rings, which are assumed only to be F-finite in the majority of our results. This mild hypothesis is satisfied in all cases of interest in finite and mixed characteristic algebraic geometry. We prove firstly that the topological Hochschild homology groups, and the homotopy groups of the fixed point spectra $TR^r$, are finitely generated modules. We use this to establish the continuity of these homology theories for any given ideal. A consequence of such continuity results is the pro Hochschild-Kostant-Rosenberg theorem for topological Hochschild and cyclic homology. Finally, we show more generally that the aforementioned finite generation and continuity properties remain true for any proper scheme over such a ring.
Peakons, Strings, and the Finite Toda Lattice RICHARD BEALS
Zakharov, Vladimir
Peakons, Strings, and the Finite Toda Lattice RICHARD BEALS Yale University DAVID H. SATTINGER Utah;92 R. BEALS, D. H. SATTINGER, AND J. SZMIGIELSKI viewpoints was explored in an unpublished paper by Mc
Average dynamics of a finite set of coupled phase oscillators
Dima, Germn C., E-mail: gdima@df.uba.ar; Mindlin, Gabriel B. [Laboratorio de Sistemas Dinmicos, IFIBA y Departamento de Fsica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabelln 1, Ciudad Universitaria, Buenos Aires (Argentina)] [Laboratorio de Sistemas Dinmicos, IFIBA y Departamento de Fsica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabelln 1, Ciudad Universitaria, Buenos Aires (Argentina)
2014-06-15T23:59:59.000Z
We study the solutions of a dynamical system describing the average activity of an infinitely large set of driven coupled excitable units. We compared their topological organization with that reconstructed from the numerical integration of finite sets. In this way, we present a strategy to establish the pertinence of approximating the dynamics of finite sets of coupled nonlinear units by the dynamics of its infinitely large surrogate.
Seven-point finite difference simulation of waterfloods
Wong, Steven Anthony
1985-01-01T23:59:59.000Z
SEVEN-POINT FINITE DIFFERENCE SIMULATION OF WATERFLOODS A Thesis by STEVEN ANTHONY WONG Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degr ee of MASTER OF SCIENCE December 1985... Major Subject: Petr oleum Engineer ing SEVEN-POINT FINITE DIFFERENCE SIHULATION OF WATERFLOODS A Thesis by STEVEN ANTHONY WONG Approved as to style and content by: hing H. Wu (Chairman of Committee) Richard A. Startzman (member) David D. Van...
Hierarchical strategy for rapid finite element analysis
Varghese, Julian
2004-09-30T23:59:59.000Z
A new methodology is introduced where the natural hierarchical character of model descriptions and simulation results are exploited to expedite analysis of problems. The philosophy and the different concepts involved are illustrated by implementing...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
a single-fluid diffuse interface model in the ALE-AMR hydrodynamics code to simulate surface tension effects. We show simula- tions and compare them to other surface tension...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
sion effects. We show the result of a test case, and compare it to the result without surface tension. The model describes droplet formation nicely. Application The ARRA-funded...
Transport coefficients of heavy quarks around $T_c$ at finite quark chemical potential
H. Berrehrah; P. B. Gossiaux; J. Aichelin; W. Cassing; J. M. Torres-Rincon; E. Bratkovskaya
2014-06-20T23:59:59.000Z
The interactions of heavy quarks with the partonic environment at finite temperature $T$ and finite quark chemical potential $\\mu_q$ are investigated in terms of transport coefficients within the Dynamical Quasi-Particle model (DQPM) designed to reproduce the lattice-QCD results (including the partonic equation of state) in thermodynamic equilibrium. These results are confronted with those of nuclear many-body calculations close to the critical temperature $T_c$. The hadronic and partonic spatial diffusion coefficients join smoothly and show a pronounced minimum around $T_c$, at $\\mu_q=0$ as well as at finite $\\mu_q$. Close and above $T_c$ its absolute value matches the lQCD calculations for $\\mu_q=0$. The smooth transition of the heavy quark transport coefficients from the hadronic to the partonic medium corresponds to a cross over in line with lattice calculations, and differs substantially from perturbative QCD (pQCD) calculations which show a large discontinuity at $T_c$. This indicates that in the vicinity of $T_c$ dynamically dressed massive partons and not massless pQCD partons are the effective degrees-of-freedom in the quark-gluon plasma.
A new finite element lifting surface technique
Kocurek, James David
1973-01-01T23:59:59.000Z
~ ~ ~ ~ ~ ~ ~ ~ ~ 34 VITA 39 vi LIST OF FIGURES Figure Page 1. Planar Panel Idealization 13 2. Vortex-Box Lifting Surface Model 14 3. Vortex-Box Trailing Wake Model 4. Spanwise Distribution Of Circulation, Planar Wing 5. Chordwise Distribution Of Circulation... coordinate ? ~ circulation strength, ft /sec 2 p ~ freestream density, slugs/ft 3 o a portion of S and W velocity potential, ft /sec 2 Subscripts a, b, c points in Cartesian space i, g indicies n ~ direction normal to a surface x, y, z with respect...
Wei, Jun
Climatological high resolution coupled climate model simulations for the maritime continent have been carried out using the regional climate model (RegCM) version 3 and the finite volume coastal ocean model (FVCOM) ...
Spdtke, P
2013-01-01T23:59:59.000Z
Modeling of technical machines became a standard technique since computer became powerful enough to handle the amount of data relevant to the specific system. Simulation of an existing physical device requires the knowledge of all relevant quantities. Electric fields given by the surrounding boundary as well as magnetic fields caused by coils or permanent magnets have to be known. Internal sources for both fields are sometimes taken into account, such as space charge forces or the internal magnetic field of a moving bunch of charged particles. Used solver routines are briefly described and some bench-marking is shown to estimate necessary computing times for different problems. Different types of charged particle sources will be shown together with a suitable model to describe the physical model. Electron guns are covered as well as different ion sources (volume ion sources, laser ion sources, Penning ion sources, electron resonance ion sources, and H$^-$-sources) together with some remarks on beam transport.
The stress field around two parallel edge cracks in a finite body
Hardin, Patrick Wayne
2012-06-07T23:59:59.000Z
the application of the Schwarz alternating method in conjunction with complex mapping techniques for modelling the stress fields around two arbitrarily oriented cracks in an infinite body (see Fig. 1. 4). M P 0. 83W I. 83W Again 19. Isolated, Single...-Ended Crack Located in a Finite Body. " Zo r A I I 0 I Figure IA. Two Aibitnuily Oiiented Conchs Located in an Infinite Body. t CHAFIXR II FULL-FIELD REPRESENTATION OF THE STRESS FIELD SURROUNDING TWO EDGE CRACKS OVERVIEW OF THE METHODOLOGY USED...
Finite size effects in the static structure factor of dusty plasmas
Davletov, A. E., E-mail: askar@physics.kz; Yerimbetova, L. T.; Mukhametkarimov, Ye. S.; Ospanova, A. K. [Department of Physics and Technology, Al-Farabi Kazakh National University, Al-Farabi av. 71, 050040 Almaty (Kazakhstan)
2014-07-15T23:59:59.000Z
Based on the previously developed pseudopotential model of the dust particles interaction, which takes into account both the finite size and screening effects, the equilibrium distribution functions are investigated in a broad range of plasma parameters. The treatment stems entirely from the renormalization theory of plasma particles interactions which leads to the so-called generalized Poisson-Boltzmann equation. In particular, an analytical expression for the static structure factor of the dust particles is proposed and its non-monotonic behavior in the hyper-netted chain approximation is found in a specified domain of plasma parameters to indicate the formation of short- or even long-range order in the system.
Nuclear spin structure in dark matter search: The finite momentum transfer limit
V. A. Bednyakov; F. Simkovic
2006-08-09T23:59:59.000Z
Spin-dependent elastic scattering of weakly interacting massive dark matter particles (WIMP) off nuclei is reviewed. All available, within different nuclear models, structure functions S(q) for finite momentum transfer (q>0) are presented. These functions describe the recoil energy dependence of the differential event rate due to the spin-dependent WIMP-nucleon interactions. This paper, together with the previous paper ``Nuclear spin structure in dark matter search: The zero momentum transfer limit'', completes our review of the nuclear spin structure calculations involved in the problem of direct dark matter search.
A note on finite abelian gerbes over toric Deligne-Mumford stacks
Jiang, Yunfeng
2008-07-01T23:59:59.000Z
-Mumford stack are again toric Deligne-Mumford stacks. 1. Introduction Let ? := (N, ?, ?) be a stacky fan of rank(N) = d as defined in [4]. If there are n one-dimensional cones in the fan ?, then modelling the construction of toric varieties [5], [6], the toric....2. From Proposition 4.6 in [3], any Deligne-Mumford stack is a ?-gerbe over an orbifold for a finite group ?. Our results are the toric case of that general result. In particular, given a stacky fan ? = (N, ?, ?), let ?red = (N, ?, ?) be the reduced stacky...
Deformable model for 3D intramodal nonrigid breast image registration with fiducial skin markers
of FSM, finite element method (FEM) is used to distribute the markers' displacements linearly over with rigid registration technique. Keywords: Intramodal image registration, finite element method, deformable, we developed a finite element method (FEM) deformable breast model to correct motion artifacts
McLeod, R.; Hawkins, R.J.; Kallman, J.S.
1991-04-01T23:59:59.000Z
Interest has recently grown in applying microwave modeling techniques to optical circuit modeling. One of the simplest, yet most powerful, microwave simulation techniques is the finite-difference time-domain algorithm (FDTD). In this technique, the differential form of the time-domain Maxwell's equations are discretized and all derivatives are approximated as differences. Minor algebraic manipulations on the resulting equations produces a set of update equations that produce fields at a given time step from fields at the previous time step. The FDTD algorithm, then, is quite simple. Source fields are launched into the discrete grid by some means. The FDTD equations advance these fields in time. At the boundaries of the grid, special update equations called radiation conditions are applied that approximate a continuing, infinite space. Because virtually no assumptions are made in the development of the FDTD method, the algorithm is able to represent a wide-range of physical effects. Waves can propagate in any direction, multiple reflections within structures can cause resonances, multiple modes of various polarizations can be launched, each of which may generate within the device an infinite spectrum of bound and radiation modes. The ability to model these types of general physical effects is what makes the FDTD method interesting to the field of optics. In this paper, we discuss the application of the finite-difference time-domain technique to integrated optics. Animations will be shown of the simulations of a TE coupler, TM grating, and a TE integrated detector. 3 refs., 1 fig.
Finite-size energy of non-interacting Fermi gases
Martin Gebert
2014-06-14T23:59:59.000Z
We prove the asymptotics of the difference of the ground-state energies of two non-interacting $N$-particle Fermi gases on the half line of length $L$ in the thermodynamic limit up to order $1/L$. We are particularly interested in subdominant terms proportional to $1/L$, called finite-size energy. In the nineties Affleck and co-authors [Aff97, ZA97, AL94] claimed that the finite-size energy equals the decay exponent occuring in Anderson's orthogonality catastrophe. It turns out that the finite-size energy depends on the details of the thermodynamic limit and typically also includes a linear term in the scattering phase shift.
Ultra-soft fermionic excitation at finite chemical potential
Jean-Paul Blaizot; Daisuke Satow
2014-05-13T23:59:59.000Z
It has been suggested previously that an ultra-soft fermionic excitation develops, albeit with a small spectral weight, in a system of massless fermions and scalar bosons with Yukawa interaction at high temperature ($T$). In this paper we study how this excitation is modified at finite chemical potential ($\\mu$). We relate the existence of the ultra-soft mode to symmetries, in particular charge conjugation, and a supersymmetry of the free system which is spontaneously broken by finite temperature and finite density effects, as argued earlier by Lebedev and Smilga. A non vanishing chemical potential breaks both symmetries explicitly, and maximally at zero temperature where the mode ceases to exist. A detailed calculation indicates that the ultra-soft excitation persists as long as $T\\gtrsim \\mu$.
Infrared finite ghost propagator in the Feynman gauge
A. C. Aguilar; J. Papavassiliou
2007-12-05T23:59:59.000Z
We demonstrate how to obtain from the Schwinger-Dyson equations of QCD an infrared finite ghost propagator in the Feynman gauge. The key ingredient in this construction is the longitudinal form factor of the non-perturbative gluon-ghost vertex, which, contrary to what happens in the Landau gauge, contributes non-trivially to the gap equation of the ghost. The detailed study of the corresponding vertex equation reveals that in the presence of a dynamical infrared cutoff this form factor remains finite in the limit of vanishing ghost momentum. This, in turn, allows the ghost self-energy to reach a finite value in the infrared, without having to assume any additional properties for the gluon-ghost vertex, such as the presence of massless poles. The implications of this result and possible future directions are briefly outlined.
Pion condensation in electrically neutral cold matter with finite baryon density
D. Ebert; K. G. Klimenko
2006-04-26T23:59:59.000Z
The possibility of the pion condensation phenomenon in cold and electrically neutral dense baryonic matter is investigated in $\\beta$-equilibrium. For simplicity, the consideration is performed in the framework of a NJL model with two quark flavors at zero current quark mass and for rather small values of the baryon chemical potential, where the diquark condensation might be ignored. Two sets of model parameters are used. For the first one, the pion condensed phase with finite baryon density is realized. In this phase both electrons and the pion condensate take part in the neutralization of the quark electric charge. For the second set of model parameters, the pion condensation is impossible if the neutrality condition is imposed. The behaviour of meson masses vs quark chemical potential has been studied in electrically neutral matter.
Material model library for explicit numerical codes
Hofmann, R.; Dial, B.W.
1982-08-01T23:59:59.000Z
A material model logic structure has been developed which is useful for most explicit finite-difference and explicit finite-element Lagrange computer codes. This structure has been implemented and tested in the STEALTH codes to provide an example for researchers who wish to implement it in generically similar codes. In parallel with these models, material parameter libraries have been created for the implemented models for materials which are often needed in DoD applications.
Fusion barrier distributions in systems with finite excitation energy
K. Hagino; N. Takigawa; A. B. Balantekin
1997-06-24T23:59:59.000Z
Eigen-channel approach to heavy-ion fusion reactions is exact only when the excitation energy of the intrinsic motion is zero. In order to take into account effects of finite excitation energy, we introduce an energy dependence to weight factors in the eigen-channel approximation. Using two channel problem, we show that the weight factors are slowly changing functions of incident energy. This suggests that the concept of the fusion barrier distribution still holds to a good approximation even when the excitation energy of the intrinsic motion is finite. A transition to the adiabatic tunneling, where the coupling leads to a static potential renormalization, is also discussed.
Fluctuation corrections on thermodynamic functions: Finite size effect
Sudarson Sekhar Sinha; Arnab Ghosh; Deb Shankar Ray
2013-04-26T23:59:59.000Z
The explicit thermodynamic functions, in particular, the specific heat of a spin system interacting with a spin bath which exerts finite dissipation on the system are determined. We show that the specific heat is a sum of the products of a thermal equilibration factor that carries the temperature dependence and a dynamical correction factor, characteristic of the dissipative energy flow under steady state from the system. The variation of specific heat with temperature is accompanied by an abrupt transition that depends on these dynamical factors characteristic of the finite system size.
Finite n Largest Eigenvalue Probability Distribution Function of Gaussian Ensembles
Leonard N. Choup
2011-01-27T23:59:59.000Z
In this paper we focus on the finite n probability distribution function of the largest eigenvalue in the classical Gaussian Ensemble of n by n matrices (GEn). We derive the finite n largest eigenvalue probability distribution function for the Gaussian Orthogonal and Symplectic Ensembles and also prove an Edgeworth type Theorem for the largest eigenvalue probability distribution function of Gaussian Symplectic Ensemble. The correction terms to the limiting probability distribution are expressed in terms of the same Painleve II functions appearing in the Tracy-Widom distribution.
Finite temperature analysis of a quasi2D dipolar gas
Ticknor, Christopher
2012-01-01T23:59:59.000Z
We present finite temperature analysis of a quasi2D dipolar gas. To do this, we use the Hartree Fock Bogoliubov method within the Popov approximation. This formalism is a set of non-local equations containing the dipole-dipole interaction and the condensate and thermal correlation functions, which are solved self-consistently. We detail the numerical method used to implement the scheme. We present density profiles for a finite temperature dipolar gas in quasi2D, and compare these results to a gas with zero-range interactions. Additionally, we analyze the excitation spectrum and study the impact of the thermal exchange.
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.
Excitation energy dependence of symmetry energy of finite nuclei
S. K. Samaddar; J. N. De; X. Vinas; M. Centelles
2007-10-11T23:59:59.000Z
A finite range density and momentum dependent effective interaction is used to calculate the density and temperature dependence of the symmetry energy coefficient Csym(rho,T) of infinite nuclear matter. This symmetry energy is then used in the local density approximation to evaluate the excitation energy dependence of the symmetry energy coefficient of finite nuclei in a microcanonical formulation that accounts for thermal and expansion effects. The results are in good harmony with the recently reported experimental data from energetic nucleus-nucleus collisions.
N. Schunck; D. Duke; H. Carr
2014-02-21T23:59:59.000Z
Understanding the mechanisms of induced nuclear fission for a broad range of neutron energies could help resolve fundamental science issues, such as the formation of elements in the universe, but could have also a large impact on societal applications in energy production of nuclear waste management. The goal of this paper is to set up the foundations of a microscopic model to study the static aspects of induced fission as a function of the excitation energy of the incident neutron, from thermal to fast neutrons. To account for the high excitation energy of the compound nucleus, we employ a statistical approach based on finite temperature nuclear density functional theory with Skyrme energy densities, which we benchmark on the fission of 239Pu(n,f). We compute the evolution of the least-energy fission pathway across multidimensional potential energy surfaces with up to five collective variables as a function of the nuclear temperature, and predict the evolution of both the inner and outer fission barriers as a function of the excitation energy of the compound nucleus. We show that the coupling to the continuum induced by the finite temperature is negligible in the range of neutron energies relevant to induced fission. We prove that the concept of quantum localization introduced recently can be extended to T>0, and we apply the method to compute the kinetic and interaction energy of fission fragments as a function of the temperature. While large uncertainties in theoretical modeling remain, we conclude that finite temperature nuclear density functional may provide a useful framework to obtain accurate predictions.
Finite-particle-number approach to physics
Noyes, H.P.
1982-10-01T23:59:59.000Z
Starting from a discrete, self-generating and self-organizing, recursive model and self-consistent interpretive rules we construct: the scale constants of physics (3,10,137,1.7x10/sup 38/); 3+1 Minkowski space with a discrete metric and the algebraic bound ..delta.. is an element of ..delta.. tau is greater than or equal to 1; the Einstein-deBroglie relation; algebraic double slit interference; a single-time momentum-space scattering theory connected to laboratory experience; an approximation to wave functions; local phase severance and hence both distant correlations and separability; baryon number, lepton number, charge and helicity; m/sub p//m/sub e/; a cosmology not in disagreement with current observations.
Gradient Plasticity Model and its Implementation into MARMOT
Barker, Erin I.; Li, Dongsheng; Zbib, Hussein M.; Sun, Xin
2013-08-01T23:59:59.000Z
The influence of strain gradient on deformation behavior of nuclear structural materials, such as boby centered cubic (bcc) iron alloys has been investigated. We have developed and implemented a dislocation based strain gradient crystal plasticity material model. A mesoscale crystal plasticity model for inelastic deformation of metallic material, bcc steel, has been developed and implemented numerically. Continuum Dislocation Dynamics (CDD) with a novel constitutive law based on dislocation density evolution mechanisms was developed to investigate the deformation behaviors of single crystals, as well as polycrystalline materials by coupling CDD and crystal plasticity (CP). The dislocation density evolution law in this model is mechanism-based, with parameters measured from experiments or simulated with lower-length scale models, not an empirical law with parameters back-fitted from the flow curves.
Modeling atmospheric deposition using a stochastic transport model
Buckley, R.L.
1999-12-17T23:59:59.000Z
An advanced stochastic transport model has been modified to include the removal mechanisms of dry and wet deposition. Time-dependent wind and turbulence fields are generated with a prognostic mesoscale numerical model and are used to advect and disperse individually released particles that are each assigned a mass. These particles are subjected to mass reduction in two ways depending on their physical location. Particles near the surface experience a decrease in mass using the concept of a dry deposition velocity, while the mass of particles located within areas of precipitation are depleted using a scavenging coefficient. Two levels of complexity are incorporated into the particle model. The simple case assumes constant values of dry deposition velocity and scavenging coefficient, while the more complex case varies the values according to meteorology, surface conditions, release material, and precipitation intensity. Instantaneous and cumulative dry and wet deposition are determined from the mass loss due to these physical mechanisms. A useful means of validating the model results is with data available from a recent accidental release of Cesium-137 from a steel-processing furnace in Algeciras, Spain in May, 1998. This paper describes the deposition modeling technique, as well as a comparison of simulated concentration and deposition with measurements taken for the Algeciras release.
Yasuya Nakayama; David Andelman
2015-01-11T23:59:59.000Z
We study the electric double layer by combining the effects of ion finite size and dielectric decrement. At high surface potential, both mechanisms can cause saturation of the counter-ion concentration near a charged surface. The modified Grahame equation and differential capacitance are derived analytically for a general expression of a permittivity epsilon(n) that depends on the local ion concentration, n, and under the assumption that the co-ions are fully depleted from the surface. The concentration at counter-ion saturation is found for any epsilon(n), and a criterion predicting which of the two mechanisms (steric vs. dielectric decrement) is the dominant one is obtained. At low salinity, the differential capacitance as function of surface potential has two peaks (so-called camel-shape). Each of these two peaks is connected to a saturation of counter-ion concentration caused either by dielectric decrement or by their finite size. Because these effects depend mainly on the counter-ion concentration at the surface proximity, for opposite surface-potential polarity either the cations or anions play the role of counter-ions, resulting in an asymmetric camel-shape. At high salinity, we obtain and analyze the crossover in the differential capacitance from a double-peak shape to a uni-modal one. Finally, several nonlinear models of the permittivity decrement are considered, and we predict that the concentration at dielectrophoretic saturation shifts to higher concentration than those obtained by the linear decrement model.
Babak, Olena, E-mail: obabak@ualberta.ca; Deutsch, Clayton V. [University of Alberta, Centre for Computational Geostatistics, Department of Civil and Environmental Engineering (Canada)], E-mail: cdeutsch@ualberta.ca
2009-03-15T23:59:59.000Z
An important aim of modern geostatistical modeling is to quantify uncertainty in geological systems. Geostatistical modeling requires many input parameters. The input univariate distribution or histogram is perhaps the most important. A new method for assessing uncertainty in the histogram, particularly uncertainty in the mean, is presented. This method, referred to as the conditional finite-domain (CFD) approach, accounts for the size of the domain and the local conditioning data. It is a stochastic approach based on a multivariate Gaussian distribution. The CFD approach is shown to be convergent, design independent, and parameterization invariant. The performance of the CFD approach is illustrated in a case study focusing on the impact of the number of data and the range of correlation on the limiting uncertainty in the parameters. The spatial bootstrap method and CFD approach are compared. As the number of data increases, uncertainty in the sample mean decreases in both the spatial bootstrap and the CFD. Contrary to spatial bootstrap, uncertainty in the sample mean in the CFD approach decreases as the range of correlation increases. This is a direct result of the conditioning data being more correlated to unsampled locations in the finite domain. The sensitivity of the limiting uncertainty relative to the variogram and the variable limits are also discussed.
Thermodynamics and Finite size scaling in Scalar Field Theory
Debasish Banerjee; Saumen Datta; Sourendu Gupta
2008-12-05T23:59:59.000Z
In this work we consider the 1-component real scalar $\\phi^4$ theory in 4 space-time dimensions on the lattice and investigate the finite size scaling of thermodynamic quantities to study whether the thermodynamic limit is attained. The results are obtained for the symmetric phase of the theory.
Thermodynamics and Finite size scaling in Scalar Field Theory
Thermodynamics and Finite size scaling in Scalar Field Theory A thesis submitted to the Tata Research, Mumbai December 2008 #12;ii #12;Synopsis In this work we study the thermodynamics of an interacting 4 theory in 4 space- time dimensions. The expressions for the thermodynamic quantities are worked
Aspects of finite temperature field theories in Ads/CFT
Brigante, Mauro
2008-01-01T23:59:59.000Z
In this dissertation I study some properties of field theories at finite temperature using the AdS/CFT correspondence. I present a general proof of an "inheritance principle" satisfied by a weakly coupled SU(N) (or U(N)) ...
Neutron in a Strong Magnetic Field: Finite Volume Effects
Brian C. Tiburzi
2014-03-04T23:59:59.000Z
We investigate the neutron's response to magnetic fields on a torus with the aid of chiral perturbation theory, and expose effects from non-vanishing holonomies. The determination of such effects necessitates non-perturbative treatment of the magnetic field; and, to this end, a strong-field power counting is employed. Using a novel coordinate-space method, we find the neutron propagates in a coordinate-dependent effective potential that we obtain by integrating out charged pions winding around the torus. Knowledge of these finite volume effects will aid in the extraction of neutron properties from lattice QCD computations in external magnetic fields. In particular, we obtain finite volume corrections to the neutron magnetic moment and magnetic polarizability. These quantities have not been computed correctly in the literature. In addition to effects from non-vanishing holonomies, finite volume corrections depend on the magnetic flux quantum through an Aharonov-Bohm effect. We make a number of observations that demonstrate the importance of non-perturbative effects from strong magnetic fields currently employed in lattice QCD calculations. These observations concern neutron physics in both finite and infinite volume.