The brick wall (of thermal conductivity 1.16 W/m ° C) of a building has dimensions

of 5 m by 7 m and is 18 cm thick.

How much heat flows through the wall in

a 17.2 h period when the average inside and

outside temperatures are, respectively, 24°C

and 8°C?

Answer in units of MJ.

Consider the growth of a 20-nm-diameter silicon nanowire onto a silicon wafer. the temperature of the wafer surface is maintained at 2400 k. assume the thermal conductivity of the silicon nanowire is 20 wm-1k-1 and all its surfaces including the tip are subjected to convection heat transfer with the coefficient h = 1×105 wm-2k-1 and t∞ = 8000 k. when the nanowire grows to l = 300 nm, what is the temperature of the nanowire tip (t (x =