A 20-mm-diameter sphere is suspended in a dry airstream with a temperature of 22°C. The power supplied to an embedded electrical heater within the sphere is 2.51 W when the surface temperature is 32°C. How much power is required to maintain the sphere at 32°C if its outer surface has a thin porous covering saturated with water? Evaluate the properties of air and the diffusion coefficient of the air-water vapor mixture at 300 K.