In a tempering process, glass plate, which is initially at a uniform temperature T i , is cooled by suddenly reducing the temperature of both surfaces to T s The plate is 20 mm thick, and the glass has a thermal diffusivity of 6 x 10 7 m 2 s (a) How long wi1l it take for the mid plane temperature to achieve 50 of its maximum possible temperature reduction (b) If (T i T s ) 300e, what is the maximum temperature gradient in the glass at the above time

Question: In a tempering process, glass plate, which is initially at a uniform temperature T i , is cooled by suddenly reducing the temperature of both

In a tempering process, glass plate, which is initially at a uniform temperature T_i, is cooled by suddenly reducing the temperature of both surfaces to T_s. The plate is 20 mm thick, and the glass has a thermal diffusivity of 6 x 10^-7 m²/s.

(a) How long wi1l it take for the mid plane temperature to achieve 50% of its maximum possible temperature reduction?

(b) If (T_i - T_s) = 300°e, what is the maximum temperature gradient in the glass at the above time?

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