Achemical plant has a tank that is in a process with alternating pressures. the tank alternates between 5 and 7 mpa for 5 cycles and then between 15 and 20 mpa for 3 cycles. each cycle that the tank goes through takes 1 hour. design a thick walled pressure vessel that has a lifetime of at least 6 months. assume that the tank has a 1.2 meter inner diameter, a ground surface finish, the applied force is axial, the internal operating temperature is 300 degrees celsius, and the reliability is 99.9%. consider stress elements at both the interior and exterior surfaces when designing the tank. (hint: it is strongly recommended to show the first iteration of calculations by hand and use a code for the following iterations to determine the optimum design.)