We construct blow-up solutions of the energy critical wave map equation on R → N with polynomial blow-up rate (t for blow-up at t = 0) in the case when N is a surface of revolution. Here we extend the blow-up range found by Carstea (ν > 1 2 ) based on the work by Krieger, Schlag and Tataru to ν > 0. This work relies on and generalizes the recent result of Krieger and the author where the target...

This work is concerned with positive classical solutions for a quasilinear parabolic equation with a gradient term and nonlinear boundary flux. We find sufficient conditions for the existence of global and blow-up solutions. Moreover, an upper bound for the ‘blow-up time’, an upper estimate of the ‘blow-up rate’ and an upper estimate of the global solution are given. Finally, some application e...

In this paper we analyze the asymptotic finite time blow-up of solutions to the heat equation with a nonlinear Neumann boundary flux in one space dimension. We perform a detailed examination of the nature of the blow-up, which can occur only at the boundary, and we provide tight upper and lower bounds for the blow-up rate for “arbitrary” nonlinear functions F , subject to very mild restrictions.

This paper deals with the blow-up properties of positive solutions to a system of two heat equations ut = ∆u, vt = ∆v in BR× (0, T ) with Neumann boundary conditions ∂u ∂η = e vp , ∂v ∂η = e uq on ∂BR × (0, T ), where p, q > 1, BR is a ball in Rn, η is the outward normal. The upper bounds of blow-up rate estimates were obtained. It is also proved that the blow-up occurs only on the boundary.

X iv :0 71 0. 13 61 v3 [ m at hph ] 1 6 O ct 2 00 7 Blow-up rate for a semi-linear accretive wave equation M. Jazar∗ and Ch. Messikh Abstract. In this paper we consider the semi-linear wave equation: utt − ∆u = ut|ut| in R where 1 ≤ p ≤ 1 + 4 N−1 if N ≥ 2. We give the optimal blow-up rate for blowing up solutions of this equation. AMS Subject Classifications: 35L05,35L67

In this paper we obtain the blow-up rate for positive solutions of ut = uxx−λu, in (0, 1)×(0, T ) with boundary conditions ux(1, t) = uq(1, t), ux(0, t) = 0. If p < 2q − 1 or p = 2q − 1, 0 < λ < q, we find that the behaviour of u is given by u(1, t) ∼ (T − t) − 1 2(q−1) and, if λ < 0 and p ≥ 2q − 1, the blow up rate is given by u(1, t) ∼ (T − t) − 1 p−1 . We also characterize the blow-up profil...

The blow-up rate estimate for the solution to a semilinear parabolic equation ut = ∆u+V (x)|u|p−1u in Ω×(0, T ) with 0-Dirichlet boundary condition is obtained. As an application, it is shown that the asymptotic behavior of blow-up time and blow-up set of the problem with nonnegative initial data u(x, 0) = Mφ(x) as M goes to infinity, which have been found in [5], are improved under some reason...