3.- Water at a temperature of 85 C flows through a thin-walled copper tube 0.03 m in diameter. The tube is enclosed by an eccentric cylindrical shell that is maintained at 45 C and has a diameter of 120 mm. The eccentricity, defined as the separation between the centers of the tube and the shell, is 20 mm. The space between the tube and the casing is filled with an insulating material that has a thermal conductivity of 0.005 W/m*K. Calculate the heat loss per unit length of the tube, and compare the result with the heat loss for a concentric arrangement.