Exothermal reaction in a sphere

Consider heat transfer in a slab with a nonlinear fourth order radiation boundary condition at the surface.[16] (Schiesser, 1991) The governing equation in dimensionless form is 

Maple s stiff solver (Rosenbrock algorithm) is used by setting the option stiff = true  

5 Method of Lines for Parabolic Partial Differential Equations 

The center of the sphere explodes after t = 0.3784 and the numerical calculations stop  

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