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Transmission Problem (transmission + problem)

Distribution by Scientific Domains

Mathematics and Statistics	85%

Selected Abstracts

Transmission problems for Maxwell's equations with weakly Lipschitz interfaces

MATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 6 2006
Andreas Axelsson
Abstract We prove sufficient conditions on material constants, frequency and Lipschitz regularity of interface for well posedness of a generalized Maxwell transmission problem in finite energy norms. This is done by embedding Maxwell's equations in an elliptic Dirac equation, by constructing the natural trace space for the transmission problem and using Hodge decompositions for operators d and , on weakly Lipschitz domains to prove stability. We also obtain results for boundary value problems and transmission problems for the Hodge,Dirac equation and prove spectral estimates for boundary singular integral operators related to double layer potentials. Copyright © 2005 John Wiley & Sons, Ltd. [source]

A transmission problem with imperfect contact for an unbounded multiply connected domain

MATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 4 2010
L. P. Castro
Abstract An analysis of the flux of certain unbounded doubly periodic multiply connected domains with circle disjoint components is performed. This is done under generalized non-ideal contact conditions on the boundary between domain components, which include analytic given data. A formula for the flux that depends on the conductivity of components, their radii, centers, the conductivity of the matrix, and also certain values of special Eisenstein functions is derived. Existence and uniqueness of solution to the problem are obtained by using a transmission problem with imperfect contact for analytic functions in corresponding Hardy spaces. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Heat transfer in composite materials with Stefan,Boltzmann interface conditions

MATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 11 2008
Yang Gufan
Abstract In this paper, we discuss nonstationary heat transfer problems in composite materials. This problem can be formulated as the parabolic equation with Stefan,Boltzmann interface conditions. It is proved that there exists a unique global classical solution to one-dimensional problems. Moreover, we propose a numerical algorithm by the finite difference method for this nonlinear transmission problem. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Heat transfer at high energy devices with prescribed cooling flow

MATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 4 2007
Jens Breuer
Abstract We study the heat transfer from a high-energy electric device into a surrounding cooling flow. We analyse several simplifications of the model to allow an easier numerical treatment. First, the flow variables velocity and pressure are assumed to be independent from the temperature which allows a reduction to Prandtl's boundary layer model and leads to a coupled nonlinear transmission problem for the temperature distribution. Second, a further simplification using a Kirchhoff transform leads to a coupled Laplace equation with nonlinear boundary conditions. We analyse existence and uniqueness of both the continuous and discrete systems. Finally, we provide some numerical results for a simple two-dimensional model problem. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Transmission problems for Maxwell's equations with weakly Lipschitz interfaces

A FEM,DtN formulation for a non-linear exterior problem in incompressible elasticity

MATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 2 2003
Gabriel N. Gatica
Abstract In this paper, we combine the usual finite element method with a Dirichlet-to-Neumann (DtN) mapping, derived in terms of an infinite Fourier series, to study the solvability and Galerkin approximations of an exterior transmission problem arising in non-linear incompressible 2d-elasticity. We show that the variational formulation can be written in a Stokes-type mixed form with a linear constraint and a non-linear main operator. Then, we provide the uniqueness of solution for the continuous and discrete formulations, and derive a Cea-type estimate for the associated error. In particular, our error analysis considers the practical case in which the DtN mapping is approximated by the corresponding finite Fourier series. Finally, a reliable a posteriori error estimate, well suited for adaptive computations, is also given. Copyright © 2003 John Wiley & Sons, Ltd. [source]

A Knowledge,based Algorithm for the Internet Transmission Control Protocol (TCP)

BULLETIN OF ECONOMIC RESEARCH, Issue 1 2002
Freek Stulp
Using a knowledge,based approach, the authors derive a protocol for the sequence transmission problem, which provides a high,level model of the Internet transmission control protocol (TCP). The knowledge,based protocol is correct for communication media where deletion and reordering errors may occur. Furthermore, it is shown that both sender and receiver eventually attain depth,n knowledge about the values of the messages for any n, but that common knowledge about the messages is not attainable. [source]

Transmission problems for Maxwell's equations with weakly Lipschitz interfaces

Minimal regularity of the solutions of some transmission problems

MATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 4 2003
D. Mercier
We consider some transmission problems for the Laplace operator in two-dimensional domains. Our goal is to give minimal regularity of the solutions, better than H1, with or without conditions on the (positive) material constants. Under a monotonicity or quasi-monotonicity condition on the constants (or on the inverses according to the boundary conditions), we study the behaviour of the solution near vertex and near interior nodes and show in each case that the given regularity is sharp. Without condition we prove that the regularity near a corner is of the form H1+,, where , is a given bound depending on the material constants. Numerical examples are presented which confirm the sharpness of our lower bounds. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Minimal regularity of the solution of some boundary value problems of Signorini's type in polygonal domains

MATHEMATISCHE NACHRICHTEN, Issue 6 2005
Denis Mercier
Abstract We study the regularity in Sobolev spaces of the solution of transmission problems in a polygonal domain of the plane, with unilateral boundary conditions of Signorini's type in a part of the boundary and Dirichlet or Neumann boundary conditions on the remainder part. We use a penalization method combined with an appropriated lifting argument to get uniform estimates of the approximated solutions in order to obtain some minimal regularity results for the exact solution. The same method allows us to consider problems with thin obstacles. It can be easily extended to 3D problems. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Anosmia after general anaesthesia: a case report

ANAESTHESIA, Issue 12 2009
I. Konstantinidis
Summary Although anaesthetic drugs are included among the aetiological factors of anosmia, limited reports exist of anosmia induced by general anaesthesia. We present the case of a 60-year-old female patient with a 3-month history of altered smell and taste immediately after recovery from general anaesthesia for a urological operation. The anaesthetic drugs used were fentanyl, propofol and sevoflurane. Clinical examination and a computed tomography brain scan did not reveal any pathology. Psychophysical testing showed anosmia and normal taste function. Imaging studies using single photon emission computed tomography of the brain were performed twice: as a baseline examination; and after odour stimulation with phenyl ethyl alcohol. Normal brain activity without reaction to odorous stimuli suggested peripheral dysfunction or stimuli transmission problems. The patient, after four months of olfactory retraining, demonstrated significant improvement. The onset of the dysfunction in relation with the imaging findings may imply that anaesthetics could induce the olfactory dysfunction. [source]