Metal casting riser design solved problems | Metal casting calculations

A cylindrical riser with diameter-to-length ratio = 1.0 is to be designed for a sand casting mold. The casting geometry is illustrated in Figure, in which the units are inches. If the mold constant in Chvorinov’s rule = 19.5 min/in2 , determine the dimensions of the riser so that the riser will take 0.5 min longer to freeze than the casting itself