A 15-mm radius pipe is going to be insulated with an insulation material (k=0.1 W/mK). The heat transfer coefficient between the pipe and the surrounding air is 10 W/m2K. What happens to heat transfer rate with respect to no-insulation (bare pipe) case if the thickness of the insulation material is I) 3 mm II) 4 mm III) 6 mm?

A wall consists of a layer of wood and a layer of cork insulation of the same thickness. The temperature inside is 34.0°C, and the temperature outside is 0.0°C. The thermal conductivity of wood is 0.130 W/(m·K) and the thermal conductivity of cork is 0.0460 W/(m·K). A) What is the temperature at the interface between the wood and the cork if the cork is on the inside and the wood on the outside? in C  B) What is the temperature at the interface if the wood is on the inside and the cork is on the outside? in C C) It doesn’t matter whether the cork is placed on the inside or the outside of the wooden wall because the temperature at the interface differs for the two cases.the temperature at the interface differs for the two cases. the temperature at the interface is the same for the two cases.the temperature at the interface is the same for the two cases. the total thermal resistance is the same for the two cases.the total thermal resistance is the same for the two cases.…

d) Compare Young's modulus E (the stiffness property) and thermal conductivity (the heat transmission property) of aluminum alloys (a non-ferrous metal), alumina (a technical ceramic), polyethylene (a thermoplastic polymer) and neoprene (an elastomer). Which has the highest modulus Which has the lowest thermal conductivity? Lest you answer in a table Material 1- Young's modulus, E GPa T-conductivity . W/m.K 2. 3- 4-

Q5A) Consider a composite spherical shell comprising an insulating layer of unknown thermal conductivity sandwiched between two layers of steel (k = 45 W/m. °C). The inner shell has 100 mm inner diameter and wall thickness of 5 mm. The outer shell has 150 mm inner diameter and wall thickness of 2 mm. The inner surface of inner spherical shell was experimentally found 120 °C while outer surface of outer spherical shell was at 67 °C. The ambient air was at 30 °C with heat-transfer coefficient at outer surface 6 W/m². °C. Determine thermal conductivity of insulating material. Then, experiment was repeated on another day when ambient air temperature was 13 °C. The inner surface temperature of inner shell and convection coefficient remained unchanged. Calculate temperature of outer surface of outer shell in this case.