A long, solid cylindrical shaft of 150 mm diameter is made of a nickel alloy (k = 16 W/m*K, ĆĀ = 8400 kg/m^3, and c = 420 J/kg*K) and is initially at a uniform temperature of 228ĆĀ°C. If it is desired to raise the temperature of the entire cylinder to at least 330ĆĀ°C using a hot gas furnace at 425ĆĀ°C with h = 94 W/m^2*K, a) determine if 15 minutes within the furnace is sufficient to accomplish this and b) determine the temperature at a point within the shaft 25 mm from the shaft's surface at this same condition of 15 minutes of heating.