It is desired to design a' cast iron monobloc vessel of Inside diameter at 20 cm and internal operating pressure at 10 MPa. For design permissible stress at 18 MPa and using the Lame's equation, calculate the shell thickness of the vessel (Hint: Derive the shell thickness formula from given Lame's equation] (12 marks) Lame's equation: P.(r) - P.(r.)* ,(r - (r (r.)- (r) (r)(r.) . P-P. x2 (r.)-(r)