Application example summary text:
EXAMPLE=117
NON-LINEAR HEAT CONDUCTION
Equation: K(U) * U,XX + Q = 0
with Q in data file or Q(X) given by SELECT_EXACT_SOURCE (defaults to
my_source_inc) via keyword use_exact_source.  Typical BC are
U(0) = T_1, U(L) = T_2, or given heat fluxes

Properties: (1)-K, (2)-C_t, (3) Q, for variable thermal
conductivity K = K_0 * (1 + C_t * T).  Defaults: 1., 0., 0.

DATA_SET 1
Six L2 elements, 10 iterations, K_0 = 50 W/(m C), C_t = 0.01 (1/C), 
Q = 0, L = 10 m
EXACT_SOL (1) = 100*(-1 + SQRT( 1 + 3*XYZ(1)/L))

DATA SET 2
Heinrich  & Pepper Ex. 6.5
Tungsten from 20 to 100 C. K_0 = 1.05 (W/cm C),  C_t = 0.002381 (1/C)
Q = 0, L = 8 cm, T(0) = 20 C, q(L) = -12 (W/cm^2)
EXACT_SOL (1) = 400*(-1.05 + SQRT( 1.21 + 0.6*XYZ(1)))
Four L3 elements 

DATA SET 3
Heinrich  & Pepper Ex. 6.5
Tungsten from 20 to 100 C. K_0 = 1.05 (W/cm C),  C_t = 0.002381 (1/C)
Q = 0, L = 8 cm, T(0) = 20 C, q(L) = -12 (W/cm^2)
EXACT_SOL (1) = 400*(-1.05 + SQRT( 1.21 + 0.6*XYZ(1)))
Four L3 elements, variable E used in error estimate (see DATA SET 2)