You are assined the task of process design for a fixed-bed carbon adsorber system. You are given the following data: the inlet airstream flows at 5000 acfm (at 95 degrees F and 1 atm) and contains .2% n-pentane by volume; the proper operating carbon capacity for n-pentane is 3.5 kg n-pentane per 100 kg carbon. What is the minimum amount (in kg) of carbon needed for each adsorber bed if you decide to have the system operate for 1 hour between bed regenerations?