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On a mathematical model for the crystallization of polymers

Maria Pia Gualdani (2003)

Bollettino dell'Unione Matematica Italiana

We consider a mathematical model proposed in [1] for the cristallization of polymers, describing the evolution of temperature, crystalline volume fraction, number and average size of crystals. The model includes a constraint W e q on the crystal volume fraction. Essentially, the model is a system of both second order and first order evolutionary partial differential equations with nonlinear terms which are Lipschitz continuous, as in [1], or Hölder continuous, as in [3]. The main novelty here is the...

On an over-determined problem of free boundary of a degenerate parabolic equation

Jiaqing Pan (2013)

Applications of Mathematics

This work is concerned with the inverse problem of determining initial value of the Cauchy problem for a nonlinear diffusion process with an additional condition on free boundary. Considering the flow of water through a homogeneous isotropic rigid porous medium, we have such desire: for every given positive constants K and T 0 , to decide the initial value u 0 such that the solution u ( x , t ) satisfies sup x H u ( T 0 ) | x | K , where H u ( T 0 ) = { x N : u ( x , T 0 ) > 0 } . In this paper, we first establish a priori estimate u t C ( t ) u and a more precise Poincaré type inequality...

On the Cauchy problem for linear hyperbolic functional-differential equations

Alexander Lomtatidze, Jiří Šremr (2012)

Czechoslovak Mathematical Journal

We study the question of the existence, uniqueness, and continuous dependence on parameters of the Carathéodory solutions to the Cauchy problem for linear partial functional-differential equations of hyperbolic type. A theorem on the Fredholm alternative is also proved. The results obtained are new even in the case of equations without argument deviations, because we do not suppose absolute continuity of the function the Cauchy problem is prescribed on, which is rather usual assumption in the existing...

On the domain dependence of solutions to the two-phase Stefan problem

Eduard Feireisl, Hana Petzeltová (2000)

Applications of Mathematics

We prove that solutions to the two-phase Stefan problem defined on a sequence of spatial domains Ω n N converge to a solution of the same problem on a domain Ω where Ω is the limit of Ω n in the sense of Mosco. The corresponding free boundaries converge in the sense of Lebesgue measure on N .

On the global regularity of subcritical Euler–Poisson equations with pressure

Eitan Tadmor, Dongming Wei (2008)

Journal of the European Mathematical Society

We prove that the one-dimensional Euler–Poisson system driven by the Poisson forcing together with the usual γ -law pressure, γ 1 , admits global solutions for a large class of initial data. Thus, the Poisson forcing regularizes the generic finite-time breakdown in the 2 × 2 p -system. Global regularity is shown to depend on whether or not the initial configuration of the Riemann...

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