clc;clear;

epsilon = 8.854e-12;

diameter = 2e-2;
Dab = 2.5;
Dbc = 2.5;
Dca = 5;

radius = diameter/2;
Deq = (Dab*Dbc*Dca)^(1/3);

Cn = (2*pi*epsilon)/(log(Deq/radius))