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A Normal Mode Stability Analysis of Numerical Interface Conditions for Fluid/Structure Interaction

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Communications in Computational Physics 2011年第7期10卷 279-304页

作者： j.w.banks B.Sjogreen Center for Applied Scientific Computing Lawrence Livermore National LaboratoryLivermoreCA 94551USA

In multi physics computations where a compressible fluid is coupled with a linearly elastic solid,it is standard to enforce continuity of the normal velocities and of the normal stresses at the interface between the fluid and the *** a numerical scheme,there are many ways that velocity-and stress-continuity can be enforced in the discrete *** paper performs a normal mode stability analysis of the linearized problem to investigate the stability of different numerical interface conditions for a model problem approximated by upwind type finite difference *** analysis shows that depending on the ratio of densities between the solid and the fluid,some numerical interface conditions are stable up to the maximal CFL-limit,while other numerical interface conditions suffer from a severe reduction of the stable *** paper also presents a new interface condition,obtained as a simplified characteristic boundary condition,that is proved to not suffer from any reduction of the stable *** experiments in one space dimension show that the new interface condition is stable also for computations with the non-linear Euler equations of compressible fluid flow coupled with a linearly elastic solid.

关键词： Finite difference method normal mode analysis fluid/structure interaction compressible fluid interface condition

CELLULAR AUTOMATA MODELLING OF GRAIN COARSENING DURING REHEATING AND VALIDATION wITH THE EXPERIMENTAL RESULTS

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Acta Metallurgica Sinica(English Letters) 2005年第2期18卷 113-120页

作者： w.H.Yu E.j.Palmiere S.P.banks j.T.Han SchoolofMaterialsScienceandEngineering UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofEngineeringMaterials UniversityofSheffieldSheffieldS13JDUK DepartmentofAutomaticControlandSystemsEngineering UniversityofSheffieldSheffieldS13J-DUK

A novel 2D cellular automata (CA) model has been developed for description of normal grain coarsening and abnormal grain coarsening process. The program reflects the grain coarsening quite well even through the average grain size becomes very large. Follow results have been obtained: (a) The model reflect the normal grain growth kinetics gradually increase with probability and grain growth speed can be controlled. Based on this result, temperature can be coupled in the model. (b) Abnormal grain growth is modelled successfully. (c) Methodology has been put forward to find the relationship between the experiment results and modelling results. The experimental work on the grain coarsening has been carried out. Graphical output matched the realistic microstructure in every detail. Because many physical parameters can be taken into account in the CA programme, this CA model could not only qualitatively demonstrate the grain growth process, but also quantitatively predict and analyse the grain coarsening process.

关键词： computer simulation grain growth microstructure reheating

Cellular automata modelling of austenite grain coarsening during reheating——I. Normal grain coarsening

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journal of University of Science and Technology Beijing 2004年第6期11卷 517-523页

作者： wanhuaYU E.j.Palmiere S.P.banks jingtaoHan MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofEngineeringMaterials UniversityofSheffieldSheffieldS13JDUK DepartmentofAutomaticControlandSystemsEngineering UniversityofSheffieldSheffieldS13JDUK

A two-dimensional cellular automaton (CA) model has been developed for thedescription of the normal grain coarsening process. The probabilistic CA method incorporatingMoore's definition of the neighbourhood is used to simulate the normal grain coarsening process witha new transition rule. The model simulates the grain coarsening process in as much detail that ispossible, from the point of initial nucleation to subsequent coarsening with computational *** unique result is that the grain coarsening speed can be controlled by the specific method, thisresult is vital to model the grain coarsening quantitatively. In order to make this model valid,experimental work has been done to provide solid evidence for this model. Comparison of themodelling result and the experimental result has been carried out.

关键词： computer simulation grain growth microstructure reheating

Cellular automata modelling of grain coarsening during reheating——Ⅱ. Abnormal grain growth

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journal of University of Science and Technology Beijing 2005年第1期12卷 26-32页

作者： wanhuaYu E.j.Palmiere S.P.banks jingtaoHan DepartmentofMaterialsEngineering UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofEngineeringMaterials UniversityofSheffieldS13JDSheffieldUK DepartmentofAutomaticControlandSystemsEngineering UniversityofSheffieldS13JDSheffieldUK

The 2-dimensional cellular automata (CA) simulation technique has been utilized to investigate the abnormal grain coarsening. The growth of abnormal grains is modelled under this assumption that different grains have different boundary energies and boundary mobilities. As temperature increases, some grains may first get rid of the particle pinning effect. Thus a high probability is obtained for atoms to jump over the boundary, so that they can consume other primary retained grains quickly. From the simulation, the characteristics of the abnormal grain coarsening under different conditions are demonstrated successfully. An experiment has also been carried out to reflect the abnormal grain coarsening on the microalloy steel. Simulation results are quite close to the experimental evidence.

关键词： computer simulation grain growth microstructure reheating

A method to evaluate REE-HFSE mineralised provinces by value creation potential, and an example of application: Gardar REE-HFSE province, Greenland

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Geoscience Frontiers 2020年第6期11卷 2141-2156页

作者： Graham j.banks Símun D.Olsen Antonio Gusak Geological Survey of Denmark and Greenland Øster Voldgade 10DK-1350CopenhagenDenmark Permanent Address:Route to Reserves Ulriksdalvej 13Valby2500CopenhagenDenmark University of Copenhagen Øster Voldgade 10DK-1350CopenhagenDenmark

The rare earth elements and high-field-strength elements(REE-HFSE)exploration sector conducts most evaluations at deposit and smaller *** is not evident how the sector performs a preceding exploration stage—rating and prioritising REE-HFSE mineralised provinces—to determine which provinces are prospective enough to warrant *** we present an objective,repeatable,low-cost method to screen any REE-HFSE province,as a foundation for district-scale investigations or asset *** is original for REE-HFSE screening,and adapted from regional scale copper,cobalt and petroleum exploration,and CO2 storage,screening *** is centred upon a mineralised province’s favourability for potential value creation,and to identify:(a)its main information gaps;(b)its weakest links;(c)its exploration maturity and remaining potential category;(d)how it compares against other REE-HFSE provinces;and(e)if further investigation is *** method incorporates geoscience,strategy,economic and socio-environmental factors in a way that is understandable and directly usable across stakeholder *** workflow is systematic,yet flexible enough to accommodate organisationspecific criteria,and usable for other *** provides the platform to build a global REE-HFSE province map and database consistently across national boundaries and *** for the extent of province exploration maturity and remaining mineral potential are *** illustrate the applicability of these methods using the Gardar REE-HFSE Province(GRHP)of south *** conclude that it is a moderate size,frontier province that is currently of questionable favourability for value *** move GRHP into a positive favourability class,its current weak links need strengthening by research,government policy and industry stakeholders:evaluate the mineral system;integrate all information geospatially and place it in the public domain;help the region improve some communi

关键词： REE HFSE Province Screening Favourability Value

Detection of Arterial Occlusions Using Viscoelastic wave Propagation

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Advances in Applied Mathematics and Mechanics 2009年第1期1卷 1-28页

作者： H.T.banks j.R.Samuels,jr. Center for Research in Scientific Computation North Carolina State UniversityCampus Box 8212RaleighNC 27695-8212USA

we consider the problem of detecting cardiac artery occlusions using stenosis driven viscoelastic(VE)waves propagated through biotissue to body surface *** investigate possible statistical model formulations(ordinary least squares(OLS),generalized least squares(GLS))and post analysis techniques(residual plots)to ascertain uncertainty in estimates as well as validity of the statistical models as part of a methodology for stenosis detection using viscoelastic waves.

关键词： Inverse problems viscoelastic models wave propagation in biotissue statistical models

Correlation of stress radiographs to injuries associated with lateral ankle instability

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world journal of Orthopedics 2021年第9期12卷 710-719页

作者： joshua w Sy Andrew j Lopez Gregory E Lausé j banks Deal Michael B Lustik Paul M Ryan Department of Orthopaedic Surgery Tripler Army Medical CenterHonoluluHI 96859United States Department of Statistics Tripler Army Medical CenterHonoluluHI 96859United States

BACKGROUND Stress radiographs have demonstrated superior efficacy in the evaluation of ankle *** To determine if there is a degree of instability evidenced by stress radiographs that is associated with pathology concomitant with ankle ligamentous *** A retrospective review of 87 consecutive patients aged 18-74 who had stress radiographs performed at a single institution between 2014 and 2020 was *** manual radiographic stress views were then correlated with magnetic resonance imaging and operative *** A statistically significant association was determined for the mean and median stress radiographic values and the presence of peroneal pathology(P=0.008 for tendonitis and P=0.020 for peroneal tendon tears).A significant inverse relationship was found between the presence of an osteochondral defect and increasing degrees of instability(P=0.043).CONCLUSION Although valuable in the clinical evaluation of ankle instability,stress radiographs are not an independent predictor of conditions associated with ankle in-stability.

关键词： Ankle stress radiographs Lateral ankle instability Osteochondral defect Arthroscopy Peroneal tendinopathy

Determination of Interrogating Frequencies to Maximize Electromagnetic Backscatter from Objects with Material Coatings

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Communications in Computational Physics 2006年第2期1卷 362-382页

作者： H.T.banks K.Ito j.Toivanen Center for Research in Scientific Computation Box 8205North Carolina State UniversityRaleighNC 27695-8205USA

The electromagnetic backscattering of a crosscut of a cruise missile coated by a thin homogeneous layer made of radar absorbent material is modeled using a finite element *** on the radar cross section and a reflection coefficient,optimization problems are formulated for evaders and interrogators leading to optimal material parameters for the coating and optimal monostatic radar operating frequencies,*** coating materials are constructed for several radar *** only dielectric permittivity gives a narrow frequency range of high absorption while also tuning magnetic permeability widens it *** the coating layers considered do not provide substantial reduction of backscattering in the entire frequency range from 0.2 to 1.6 *** experiments also demonstrate that the reflection coefficient based on a simple planar geometry can predict well the strength of radar cross section in the sector of interest with a substantially reduced computational burden.

关键词： Radar cross section radar absorbent material optimization finite element model

Insights into the role of jasmonic acid-mediated defenses against necrotrophic and biotrophic fungal pathogens

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Frontiers in Biology 2012年第1期7卷 48-56页

作者： Christopher j. ANTICO Chad COLON Taylor banks Katrina M. RAMONELL Department of Biological Sciences University of Alabama Tuscaloosa AL 35487 USA

jasmonic acid （jA） is a natural hormone regulator involved in development, responses against woundingand pathogen attack. Upon perception of pathogens, jA is synthesized and mediates a signaling cascade initiating various defense responses. Traditionally, necrotrophic fungi have been shown to be the primary activators of jA- dependent defenses through the jA-receptor, COIl. Conversely, plants infected with biotrophic fungi have classically been associated with suppressing jA-mediated responses. However, recent evidence has shown that certain biotrophic fungal species also trigger activation of jA-mediated responses and mutants deficient in jA signaling show an increase in susceptibility to certain biotrophic fungal pathogens. These findings suggest a new role for jA in defense against fungal biotrophs. This review will focus on recent research advancing our knowledge of jA-dependant responses involved in defense against both biotrophic and necrotrophic fungi.

关键词： jasmonic acid (jA) methyl jasmonate (MejA) biotrophic fungi necrotrophic fungi COIl