An external flow of water was applied on top of the planar surface of a fibrous polymer solid membrane $($with finite thickness$).$ You are told that moxifloxacin $($an antibiotics which is water soluble$)$ was encapsulated within the matrix of polymer solid membrane as mentioned above. You are told that the flux of moxifloxacin from the polymer membrane surface was determined as $2\mathrm{.}4{10}^{-5}$mol$\frac{e}{m^2(s)}$ under water flow with constant velocity profile. The concentration of moxifloxacin inside the polymer solid membrane $($at the region just next to the water layer$)$ is given as $7\mathrm{.}2$ mole$/$L$.$ Also, the concentration of moxifloxacin in the water far away from the surface of polymer solid membrane was known to be $0\mathrm{.}6$mol$\frac{e}{L}.$ The values of mass transfer coefficients are known too as follows: $k_{as}=3\mathrm{.}5{10}^{-9}\frac{m}{s}$;$k_{as}=9\mathrm{.}7{10}^9\frac{m}{s}.$

Calculate the partition coefficient ${}_{\text{A}\text{f}\text{s}}$ of moxifloxacin between water and polymer solid membrane.