Tests in a laboratory adsorption column ¹/₄ in. in diameter and 12 in. long, packed with 20 x 32 mesh particles of activated carbon, gave good removal of solvent from an air stream, but t_b was too short (1.5 h) and ΔP would be too high in a longer bed 

(a) If 12 x 16 mesh particles were used in a 3-ft bed, by what factor would ΔP be changed? 

(b) If LUB was 4.0 in. for the 20 x 32 mesh bed, what would it be for the larger particles? What would be the new value of t_b?