Humans are able to control their heat production rate and heat loss rate to maintain a nearly constant core temperature of Tc 37 C under a wide range of environmental conditions. This process is called thermoregulation. From the perspective of calculating heat transfer between a human body and its surroundings, we focus on a layer of skin and fat, with its outer surface exposed to the environment and its inner surface at a temperature slightly less than the core temperature, Ti 35 C 308 K. Consider a person with a skin/fat layer of thickness L 3 mm and effective thermal conductivity k 0.3 W/m K. The person has a surface area A 1.8 m2 and is dressed in a bathing suit. The emissivity of the skin is 0.95. 1. When the person is in still air at T 297 K, what is the skin surface temperature and rate of heat loss to the environment? Convection heat transfer to the air is characterized by a free convection coefficient of h 2 W/m2 K. 2. When the person is in water at T 297 K, what is the skin surface temperature and heat loss rate? Heat transfer to the water is characterized by a convection coefficient of h 200 W/m2 K.