The solubility of hydrogen gas in steel in terms of its mass fraction is given as WH, = 2.09 X 104 exp(-3950/T)P p05 where PH2 is the partial pressure of hydrogen in bars and T is the temperature in K. If natural gas is transported in a 1-cm- thick, 3-m-internal-diameter steel pipe at 500 kPa pressure and the mole fraction of hydrogen in the natural gas is 8 percent, determine the highest rate of hydrogen loss through a 100-m- long section of the pipe at steady conditions at a temperature of 293 K if the pipe is exposed to air. Take the diffusivity of hydrogen in steel to be 2.9 x 10-13 m2/s.