Assume that a surface-grinding operation is being carried out under the following conditions: D = 250 mm D=250 mm, d = 0.4 mm d=0.4 mm, v = 0.5 m / s v=0.5 m/s, and V = 50 m / s V=50 m/s. These conditions are then changed to the following: D = 150 mm D=150 mm, d = 0.4 mm d=0.4 mm, v = 0.3 m / s v=0.3 m/s, and V = 25 m / s V=25 m/s. What is the difference in the temperature rise from the initial condition?