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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

Stability of Finite Difference Discretizations of Multi-physics Interface Conditions

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Communications in Computational physics 2013年第2期13卷 386-410页

作者： Björn Sjögreen Jeffrey W.banks Center for Applied Scientific Computing Lawrence Livermore National LaboratoryLivermoreCA 94551USA

We considermulti-physics computationswhere theNavier-Stokes equations of compressible fluid flow on some parts of the computational domain are coupled to the equations of elasticity on other parts of the computational *** different subdomains are separated by well-defined *** consider time accurate computations resolving all time *** such computations,explicit time stepping is very *** address the issue of discrete interface conditions between the two domains of different physics that do not lead to instability,or to a significant reduction of the stable time step *** such interface conditions is *** discretize the problem with high order centered difference approximations with summation by parts boundary *** derive L2 stable interface conditions for the linearized one dimensional discretized ***,we generalize the interface conditions to the full non-linear equations and numerically demonstrate their stable and accurate performance on a simple model *** energy stable interface conditions derived here through symmetrization of the equations contain the interface conditions derived through normal mode analysis by banks and Sj¨ogreen in[8]as a special case.

关键词： Fluid-structure interaction finite difference method summation by parts multiphysics interface condition

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

Modelling of propagating Shear Waves in Biotissue Employing an Internal Variable Approach to Dissipation

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Communications in Computational physics 2008年第3期3卷 603-640页

作者： H.T.banks Nicholas S.Luke Center for Research in Scientific Computation North Carolina State UniversityRaleighNC 27695-8205USA.

The ability to reliably detect coronary artery disease based on the acousticnoises produced by a stenosis can provide a simple, non-invasive technique for *** research exploits the shear wave fields in body tissue to detect andanalyze coronary stenoses. The methods and ideas outlined in earlier efforts [6] includinga mathematical model utilizing an internal strain variable approximation tothe quasi-linear viscoelastic constitutive equation proposed by Fung in [19] is extendedhere. As an initial investigation, a homogeneous two-dimensional viscoelastic geometryis considered. Being uniform in θ, this geometry behaves as a one dimensionalmodel, and the results generated from it are compared to the one dimensional resultsfrom [6]. To allow for different assumptions on the elastic response, several variationsof the model are considered. A statistical significance test is employed to determine ifthe more complex models are significant improvements. After calibrating the modelwith a comparison to previous findings, more complicated geometries are *** involving a heterogeneous geometrywith a uniformring running throughthe original medium, a θ-dependent model which considers a rigid partial occlusionformed along the inner radius of the geometry, and a model which combines the ringand occlusion are presented.

关键词： Viscoelasticity partial differential equations shear waves biotissue.

A Brief Review of Elasticity and Viscoelasticity for Solids

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Advances in Applied Mathematics and Mechanics 2011年第1期3卷 1-51页

作者： Harvey Thomas banks Shuhua Hu Zackary R.Kenz Center for Research in Scientific Computation and Department of Mathematics North Carolina State UniversityRaleighNC 27695-8212USA

There are a number of interesting applications where modeling elastic and/or viscoelastic materials is fundamental,including uses in civil engineering,the food industry,land mine detection and ultrasonic *** we provide an overview of the subject for both elastic and viscoelastic materials in order to understand the behavior of these *** begin with a brief introduction of some basic terminology and relationships in continuum mechanics,and a review of equations of motion in a continuum in both Lagrangian and Eulerian *** complete the set of equations,we then proceed to present and discuss a number of specific forms for the constitutive relationships between stress and strain proposed in the literature for both elastic and viscoelastic *** addition,we discuss some applications for these constitutive ***,we give a computational example describing the motion of soil experiencing dynamic loading by incorporating a specific form of constitutive equation into the equation of motion.

关键词： Mathematical modeling Eulerian and Lagrangian formulations in continuum mechanics elasticity viscoelasticity computational simulations in soil constitutive relationship

Absolute parameters of young stars:pU pup

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Research in Astronomy and Astrophysics 2021年第10期21卷 151-163页

作者： Ahmet Erdem Derya Surgit Timothy S.banks Burcu Ozkardes Edwin Budding Canakkale Onsekiz Mart University Astrophysics Research Center and Ulupinar ObservatoryTR-17100CanakkaleTurkey Department of physics Faculty of Arts and SciencesCanakkale Onsekiz Mart UniversityTerzioglu KampusuTR-17100CanakkaleTurkey Department of Space Sciences and Technologies Faculty of Arts and SciencesCanakkale Onsekiz Mart UniversityTerzioglu KampusuTR-17100CanakkaleTurkey Data Science Nielsen200 W JacksonChicagoIL 60606USA physics&Astronomy Harper College1200 W Algonquin RdPalatineIL 60067USA Visiting astronomer Mt.John ObservatoryUniversity of CanterburyPrivate Bag 4800Christchurch 8140NZ Carter Observatory Wellington 6012New Zealand School of Chemical&physical Sciences Victoria University of WellingtonWellington 6012New Zealand Variable Stars South RASNZPO Box 3181WellingtonNew Zealand

We present combined photometric and spectroscopic analyses of the southern binary star pU ***-resolution spectra of this system were taken at the University of Canterbury *** Observatory in the years 2008 and again in *** find the light contribution of the secondary component to be only 2%of the total light of the system in optical wavelengths,resulting in a single-lined spectroscopic *** TESS data revealed grazing eclipses within the light minima,though the tidal distortion,examined also from Hipparcos data,remains the predominating light curve *** model shows pU pup to have the more massive primary relatively close to filling its Roche *** pup is thus approaching the rare‘fast phase’of interactive(Case B)*** adopted absolute parameters are as follows:M_(1)=4.10(±0.20)M_(⊙),M_(2)=0.65(±0.05)M_(⊙),R_(1)=6.60(±0.30)R_(⊙),R_(2)=0.90(±0.10)R_(⊙);T_(1)=11500(±500)K,T_(2)=5000(±350)K;photometric distance=186(±20)pc,age=170(±20)*** less-massive secondary component is found to be significantly oversized and overluminous compared to standard main sequence *** discuss this discrepancy referring to heating from the reflection effect.

关键词： (stars:)binaries(including multiple):close stars:early-type stars:individual(pU pup) Galaxy:stellar content

pRELIMINARY STUDY ON MAKING OF WATER RESISTANCE WOOD FIBERBOARD

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Journal of Northeast Forestry University 1991年第2期2卷 54-60页

作者： banks W.B. Jones G.L. North Wales University North Wales University United KingdomUnited Kingdom

In the present study,described that preparation of oligoesterified wood fibre by theaddition reaction of the wood fibre with maleic anhydride(MA)and allyl glycidyl ether(AGE).Further,made of crosslinkable oligoesterified fiber board at high temperature and underhigh pressues,accompanying plasticization of the wood fibre *** product exhibitedthe high the modulus of repture in bending(MOR),good water repellency and dimesionalstability.

关键词： Wood fibre Oligoestcriflcation Fiberboard

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

Recent development of LiNi_xCo_yMn_zO_2:Impact of micro/nano structures for imparting improvements in lithium batteries

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Transactions of Nonferrous Metals Society of China 2013年第1期23卷 108-119页

作者：潘成迟 Craig E.banks 宋维鑫王驰伟陈启元纪效波中南大学化学化工学院有色金属资源化教育部重点实验室长沙410083 Faculty of Science and Engineering School of BiologyChemistry and Health ScienceDivision of Chemistry and MaterialsManchester Metropolitan UniversityChester StreetManchester M1 5GDLancsUK 天津市捷威动力工业有限公司天津300380

The recent advancement in the design,synthesis,and fabrication of micro/nano structured LiNixCoyMnzO2 with one-,two-,and three-dimensional morphologies was *** major goal is to highlight LiNixCoyMnzO2 materials,which have been utilized in lithium ion batteries with enhanced energy and power density,high energy efficiency,superior rate capability and excellent cycling stability resulting from the doping,surface coating,nanocomposites and nano-architecturing.

关键词： lithium-ion battery micro/nano structures LiNixCoyMnzO2 doping surface coating composite materials