A certain superinsulation material having a thermal conductivity of 2 x 10^-4 W/m.C is used to isulate a tank of liquid nitrogen that is maintained at -196 degrees celcius; 199 kj is required to vaporize each kilogram mass of nitrogen at this temperature. Assuming that the tank is sphere having an inner diameter(ID) of 0.56 m, estimate the amount of nitrogen vaporized per day for an insulation thickness of 2.5 cm and an ambient temperature of 25 degrees celcius. Assume that the outer temperature of the insulation is 25 degrees celcius.