Hi Peter,
If I were to find the critical pressure and temperature at the same time.
For example,
The applied loads are T = 100°C , P = 20MPa in the buckling section
Tcrit = 100 x 3.8853e-2 . Pcrit= 20MPa x 3.8853e-2
Would that be correct? Because when I tried this two and plug in the Pcrit and Tcrit, the value does not come close to 1.