Consider a solid object separating two streams of air (one at higher temperature T1, and the other at lower temperature T4). Assume that the heat transfer coefficient of air is 15W/m2K, and the thermal conductivity of the solid is 80.2W/mK. The temperatures of the solid surfaces in contact with streams of air are T2 and T3, as shown in the figure. All other surfaces are well insulated. a) Draw an appropriate thermal circuit diagram for the heat transfer process above, showing the correct temperature points, resistance equations, and direction of heat transfer. [20 pts] b) Calculate the total thermal resistance (Rtot) in the process above. [20 pts]