A part is to be cast (the Casting in the figure). The volume of this part is 300,0000 mm and the surface area is 160,000 mm. Assume the mold constant C is 1 and exponent n is 2. We are considering two riser designs: (1) A single riser design. The solidification time of the riser needs to be 1.3x of the casting solidification time. (2) A dual-riser design. The two risers have the same dimensions. In this case, the solidification time of the riser only needs to be 1.05x of the casting solidification time. In both designs, the riser diameter and height are the same (h = d) 120 mm Basin Runner Casting Single Riser Riser Riser Casting Dual Riser Riser a. Calculate the solidification of the casting. (6 pts) b. Calculate the riser dimension of the single riser design, round up to the nearest 5 or 10 mm. (8 pts) c. Calculate the riser dimension of the dual-riser design, round up to the nearest 5 or 10 mm. (8 pts) d. Calculate the yield rates of both designs. (10 pts) e. If the basin-to-gate elevation is 120 mm, what is the minimal runner diameter when using the single riser design? (8 pts)