c0 1000[mol/m^3] Initial concentration k_ads 1e-6[m^3/(mol*s)] Forward rate constant k_des 1e-9[1/s] Backward rate constant Gamma_s 1000[mol/m^2] Active site concentration Ds 1e-11[m^2/s] Surface diffusivity D 1e-9[m^2/s] Gas diffusivity v_max 1[mm/s] Maximum velocity delta 0.1[mm] Channel width