A cylindrical pressure vessel has an inner diameter of 150 mm and a wall thickness of 5 mm, and it contains a pressure of 20 MPa. A leak-before-break criterion must be met, with a safety factor of at least Xa-9 on crack length, requiring amax Xa t. (You have learned that a should be at least 2 to ensure LBB. Your design criteria should be a lot more conservative in this case with Xa -9). (a) Is the vessel safe if it is made from 300-M steel with 300C temper, which has Kic of 65 MPavm? (b) Is the vessel safe if it is made from A517-F steel, which has Kic of 187 MPavm? (c) What minimum fracture toughness is required for the materials in this application? (d) What is the safety factor (Xx) on K relative to KIC due to the Xa -9 requirement?