Air with an average bulk temperature of 338.8 K is flowing through a packed bed of spheres having a diameter of 12.7 mm. Packed bed and spheres are maintained at 400 K. The void fraction ε of the bed is 0.38 and the bed has a diameter of 0.61 m and a height of 2.44 m. The air enters the bed at 1.10 atm abs at the rate of 0.358 kg/s. Calculate the Colburn J factor and heat transfer coefficient for air.