Potatoes with a density of 1049 kg/m, a moisture content of 83% and a side of 12.5 mm, cut in the shape of a backgammon bowl, were frozen in a cold air stream at -35C. The thawing process of these carrots will be carried out in a still air environment at 20 C. The freezing initial temperature of the potatoes is -2C, the thermal conductivity coefficient above this temperature is 0.56 W/m C, the heat transfer coefficient is 25 W/m "C. Calculate the thawing time of the potatoes accordingly.