1,720,999 research outputs found

    Qualitative properties for solutions of reaction-diffusion parabolic systems and their gradients

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    The aim of this paper is to investigate a class of reaction–diffusion parabolic systems with initial and boundary values of 4 Dirichlet type. Sufficient conditions on data are established in order to preclude blow-up and obtain that the solutions and their 5 gradients decay exponentially in time

    Explicit estimates for blow-up solutions to parabolic systems under nonlocal boundary conditions

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    This paper deals with a nonlinear parabolic system, which contains a nonlocal term in the boundary conditions. Explicit estimates from above and from below for the blow-up time are obtained by means of suitable inequalities and appropriate auxiliary functions

    Upper and lower solutions in quasilinear parabolic boundary value problems

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    The authors study a class of initial boundary value problems associated with parabolic quasilinear equations: by introducing special auxiliary functions, upper and lower solutions are obtained, which turn out to be sharp in the sense that they coincide with the solution in particular situations

    Exponential decay bounds for nonlinear heat problems with Robin boundary conditions

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    We investigate the behavior of the solution of a nonlinear heat problem, when Robin conditions are prescribed on the boundary ∂Ω×(t > 0), Ω a bounded R2 domain. We determine conditions on the geometry and data sufficient to preclude the blow up of the solution and to obtain an exponential decay bound for the solution and its gradient

    Sharp upper and lower solutions in some parabolic problems

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    In this paper we construct upper and lower solutions for a class of parabolic initial-boundary value problems in terms of the solution ψ(x)\psi(x) of the St-Venant problem and first eigenvalue problem. These bounds are sharp in the sense that they coincide with the exact solution in particular situations

    Bounds for blow-up time in nonlinear parabolic system

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    We consider a nonlinear parabolic system with Neumann boundary conditions which solution may blow up in finite time t*: We determine a lower bound for t* by using a Sobolev type inequality. In addition an upper bound for t* is obtained, under alternative conditions on the non linearities

    Blow-up phenomena in reaction-diffusion systems

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    In this paper we deal with the blow-up phenomena of solutions to two different classes of reaction-diffusion systems coupled through nonlinearities with nonlinear boundary conditions. By using a differential inequality technique, we derive upper and lower bounds for the blow-up time, if blow-up occurs. Moreover by introducing suitable auxiliary functions, we give suffcient conditions on data in order to obtain global existence
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