Cylindrical tank with hemispherical ends is used store liquid oxygen at -183°C. The diameter of the tank is 1.5 m and the total length is 8 m. The tank is covered with a 10 cm thick layer of insulation. Determine the thermal conductivity of the insulation so that the boil-off rate does not exceed 10.8 kg/hr. The latent heat of vaporization of liquid oxygen is 214 kJ/kg. Assume that the outer surface temperature of the insulation is 27°C and that the thermal resistance of the wall of the tank is negligible.