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On an isotropic porous solid cylinder:the analytical solution and sensitivity analysis of the pressure

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1499-1522页

作者： H.ASGHARi L.MiLLER R.PENTA J.MERODiO Departamento de matematica aplicada a las TiC ETS de Ingenieria de Sistemas InformaticosUniversidad Politecnica de MadridMadrid 28031Spain School of Mathematics and Statistics University of GlasgowGlasgow G128QQU.K.

Within this work,we perform a sensitivity analysis to determine the influence of the material input parameters on the pressure in an isotropic porous solid *** provide a step-by-step guide to obtain the analytical solution for a porous isotropic elastic cylinder in terms of the pressure,stresses,and elastic *** obtain the solution by performing a Laplace transform on the governing equations,which are those of Biot's poroelasticity in cylindrical polar *** enforce radial boundary conditions and obtain the solution in the Laplace transformed domain before reverting back to the time *** sensitivity analysis is then carried out,considering only the derived pressure *** analysis finds that the time t,Biot's modulus M,and Poisson's ratio ν have the highest influence on the pressure whereas the initial value of pressure P_(0) plays a very little role.

关键词： sensitivity analysis Laplace transform cylindrical polar coordinate Biot's modulus cylinder

Quasilinear elliptic problems with exponential growth via the Nehari manifold method: Existence of nonnegative and nodal solutions

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Acta Mathematica Sinica,English Series 2024年

作者： Giovany FiGUEiREDO Sandra Moreira Ricardo Ruviaro Address Departamento de matematica Universidade de Brasilia Departamento de matematica e informatica Universidade Estadual do Maranhao Departamento de matematica Universidade de Brasilia

in this paper we will be concerned with the problem -Δu-1/2Δ(a（x）u2)u+V（x）u=f（u）,x∈R2，where V is a potential continuous and f : R → R is a superlinear continuous function with exponential subcritical or exponential critical growth. We use as a main tool the Nehari manifold method in order to show existence of nonnegative solutions and existence of nodal solutions. Our results complement the classical result of solutions for quasilinear Schrodinger equations via the Nehari method due to Jia-quan Liu, Ya-qi Wang and Zhi-Qiang Wang in the sense that in this article we are considering nonlinearity of the exponential type.

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A LOW-COST OPTiMiZATiON APPROACH FOR SOLViNG MiNiMUM NORM LiNEAR SYSTEMS AND LiNEAR LEAST-SQUARES PROBLEMS

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Journal of Computational Mathematics 2024年第4期42卷 932-954页

作者： Debora Cores Johanna Figueroa Defense University Center at the Spanish Naval Academy Plaza de Espana36920 MarinPontevedraSpain Departamento de matematica Facultad de MatematicaPontificia Universidad Catolica de ChileAv.Vicuna Mackenna 4860San JoaquinSantiago 894000Chile

Recently,the authors proposed a low-cost approach,named Optimization Approach for Linear Systems(OPALS)for solving any kind of a consistent linear system regarding the structure,characteristics,and dimension of the coefficient matrix *** results obtained by this approach for matrices with no structure and with indefinite symmetric part were encouraging when compare with other recent and well-known *** this work,we proposed to extend the OPALS approach for solving the Linear Least-Squares Problem(LLSP)and the Minimum Norm Linear System Problem(MNLSP)using any iterative low-cost gradient-type method,avoiding the construction of the matrices AT A or AAT,and taking full advantage of the structure and form of the gradient of the proposed nonlinear objective function in the gradient *** combination of those conditions together with the choice of the initial iterate allow us to produce a novel and efficient low-cost numerical scheme for solving both ***,the scheme presented in this work can also be used and extended for the weighted minimum norm linear systems and minimum norm linear least-squares *** include encouraging numerical results to illustrate the practical behavior of the proposed schemes.

关键词： Nonlinear convex optimization Gradient-type methods Spectral gradient method Minimum norm solution linear systems Linear least-squares solution

A Stable FE-FD Method for Anisotropic Parabolic PDEs with Moving interfaces

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Communications on Applied Mathematics and Computation 2024年第2期6卷 992-1012页

作者： Baiying Dong Zhilin Li Juan Ruiz-Alvarez School of Civil and Hydraulic Engineering NingXia UniversityYinchuan 750021NingxiaChina School of Mathematics and Computer Science NingXia Normal UniversityGuyuan 756000NingxiaChina Department of Mathematics North Carolina State UniversityRaleighNC 27695-8205USA Departamento de matematica aplicada y Estadistica Universidad Politecnica de CartagenaCartagenaSpain

in this paper,a new finite element and finite difference(FE-FD)method has been developed for anisotropic parabolic interface problems with a known moving interface using Cartesian *** the spatial discretization,the standard P,FE discretization is applied so that the part of the coefficient matrix is symmetric positive definite,while near the interface,the maximum principle preserving immersed interface discretization is *** the time discretization,a modified Crank-Nicolson discretization is employed so that the hybrid FE-FD is stable and second order *** terms are needed when the interface crosses grid *** moving interface is represented by the zero level set of a Lipschitz continuous *** experiments presented in this paper confirm second orderconvergence.

关键词： Anisotropic parabolic interface problem Hybrid finite element and finite difference(FE-FD)discretization Modified Crank Nicolson scheme

On a Shallow Water Model for the Simulation of Turbidity Currents

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Communications in Computational Physics 2009年第9期6卷 848-882页

作者： T.Morales de Luna M.J.Castro Dıaz C.Pares Madronal E.D.Fernandez Nieto Analisis Matematico Facultad de Ciencias–Univ.MalagaCampus de Teatinoss/n29071-MalagaSpain dpto.matematica aplicada i ETS Arquitectura–Univ.SevillaAvda.Reina Mercedes N.241012-SevillaSpain

We present a model for hyperpycnal plumes or turbidity currents that takes into account the interaction between the turbidity current and the bottom,considering deposition and erosion effects as well as solid transport of particles at the bed load due to the *** entrainment from the ambient water in which the turbidity current plunges is also *** of ambient water is neglected and the rigid lid assumption is *** model is obtained as a depth-average system of equations under the shallow water hypothesis describing the balance of fluid mass,sediment mass and mean *** character of the system is analyzed and numerical simulations are carried out using finite volume schemes and path-conservative Roe schemes.

关键词： Turbidity currents hyperbolic systems finite volume methods path-conservative schemes numerical modeling

Stochastic Maximum Principle for Optimal Advertising Models with Delay and Non-Convex Control Spaces

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Advances in Pure Mathematics 2024年第6期14卷 442-450页

作者： Giuseppina Guatteri Federica Masiero Dipartimento di matematica Politecnico di Milano via Bonardi Milano Italia Dipartimento di matematica e Applicazioni Universit di Milano-Bicocca via Cozzi Milano Italia

in this paper we study optimal advertising problems that model the introduction of a new product into the market in the presence of carryover effects of the advertisement and with memory effects in the level of goodwill. in particular, we let the dynamics of the product goodwill to depend on the past, and also on past advertising efforts. We treat the problem by means of the stochastic Pontryagin maximum principle, that here is considered for a class of problems where in the state equation either the state or the control depend on the past. Moreover the control acts on the martingale term and the space of controls U can be chosen to be non-convex but now the space of controls U can be chosen to be non-convex. The maximum principle is thus formulated using a first-order adjoint Backward Stochastic Differential Equations (BSDEs), which can be explicitly computed due to the specific characteristics of the model, and a second-order adjoint relation.

关键词： Stochastic Optimal Control Delay Equations Advertisement Models Stochastic Maximum Principle

A multi-shot target wheel assembly for high-repetition-rate, laser-driven proton acceleration

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High Power Laser Science and Engineering 2024年第2期12卷 87-94页

作者： J.Penas A.Bembibre D.Cortina-Gil L.Martin A.Reija C.Ruiz M.Seimetz A.Alejo J.Benlliure instituto Galego de Fisica de Altas Enerxias Universidade de Santiago de CompostelaSantiago de CompostelaSpain Laboratorio Laser de Aceleracion y Aplicaciones RIAIDTUniversidade de Santiago de CompostelaSantiago de CompostelaSpain instituto Universitario de Física Fundamental y matematicas y dpto.de Didactica de la matematica y de las Ciencias Experimentales Universidad de SalamancaSalamancaSpain instituto de instrumentación para imagen Molecular(i3M) CSIC-Universitat Politecnica de ValenciaValenciaSpain

A multi-shot target assembly and automatic alignment procedure for laser–plasma proton acceleration at high repetition rate are *** assembly is based on a multi-target rotating wheel capable of hosting more than 5000 targets,mounted on a 3D motorized stage to allow rapid replenishment and alignment of the target material between laser *** automatic alignment procedure consists of a detailed mapping of the impact positions at the target surface prior to the irradiation that ensures stable operation of the target,which alongside the purpose-built design of the target wheel,enables operation at rates up to 10 *** and continuous laser-driven proton acceleration at 10 Hz is demonstrated,with observed cut-off energy stability about 15%.

关键词： high repetition rate laser-plasma acceleration multi-shot operation proton source target assembly

immersed Boundary Approach to Biofilm Spread on Surfaces

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Communications in Computational Physics 2022年第1期31卷 257-292页

作者： Ana Carpio Rafael Gonzalez-Albaladejo Departamento de matematica aplicada Universidad Complutense28040 MadridSpain

We propose a computational model to study the growth and spread of bacterial biofilms on interfaces,as well as the action of antibiotics on *** membranes are represented by boundaries immersed in a fluid matrix and subject to interaction ***,division and death of bacterial cells follow dynamic energy budget rules,in response to variations in environmental concentrations of nutrients,toxicants and substances released by the *** this way,we create,destroy and enlarge boundaries,either spherical or *** forces represent details of the interaction between cells,and the interaction with the *** can investigate geometrical arrangements and the formation of porous *** simulations illustrate the evolution of top views and diametral slices of small biofilm seeds,as well as the action of *** show that cocktails of antibiotics targeting active and dormant cells can entirely eradicate a biofilm.

关键词： Hybrid multiscale models immersed boundary methods dynamic energy budget models bacterial biofilm antibiotic resistance

Studies on Standard Formation Enthalpies of Rare Earth Compounds by Using Structural Parameters

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Journal of Rare Earths 2000年第3期18卷 237-239页

作者：杨锋冯琳 Grupo de Mecanica Celeste i. Departamento de matematica aplicada a la ingenieria. E. T. S. de ingenieros industriales. Universidad de Valladolid. E - 47 011 Valladolid Spain Grupo de Mecanica Celeste i. Departamento de matematica aplicada a la ingenieri

The atomic structural parameter P-i = (Z(i)*/n(i)*) (1 + n(i)*/n(i)) (1 + m(i)/Z) and the molecular structural parameter [GRAPHiCS] are defined. The standard formation enthalpies (Delta(f)H(m)(phi)) of 74 species of rare earth compounds were studied with P, and the correlation coefficient is R > 0.94. The structural factors and the properties of rare earth compounds are influenced by the Z(i)*, n(i)*, n(i), m(i), Z. This study has special referential value to predict the properties of rare earth compounds.

关键词： rare earths structural parameter standard formation enthalpies