Drying Biological Material in Tray Dryer. A granular biological material wet with water is being dried in a pan 0.305 × 0.305 m and 38.1 mm deep. The material is 38.1 mm deep in the pan, which is insulated on the sides and bottom. Heat transfer is by convection from an air stream flowing parallel to the top surface at a velocity of 3.05 m/s, having a temperature of 65.6°C and humidity H = 0.010 kg H2O/kg dry air. The top surface receives radiation from steamheated pipes whose surface temperature TR = 93.3°C. The emissivity of the solid is ε = 0.95. It is desired to keep the surface temperature of the solid below 32.2°C so that decomposition will be kept low. Calculate the surface temperature and the rate of drying for the constant-rate period.