A shaft machined of AISI 1022 steel having σuts = 70 ksi and σy = 52 ksi is loaded cyclically. The loading is characterized by the maximum bending moment Mmax = 1,500 lb-ft and minimum bending moment Mmin = 500 lb-ft at room temperature. Determine the diameter of the shaft, d [in], assuming the safety factor SF = 2 against both alternating and mean load components increasing in service with a constant ratio. The shaft has no any steps in its geometry.