How you calculate the klinkenberg correction of air permeability samples?

The Klinkenberg correction for air permeability is calculated using the formula: ( k_{a} = k_{g} \cdot (1 + \frac{b}{P}) ), where ( k_{a} ) is the corrected air permeability, ( k_{g} ) is the measured gas permeability, ( P ) is the pressure, and ( b ) is a constant related to the flow characteristics of the gas through the porous material. The constant ( b ) can be determined from the slope of a plot of ( k_{g} ) versus ( 1/P ) using linear regression. This correction accounts for the Knudsen effect, which becomes significant at low pressures.