${\pi }_0=1-\frac{x_0}{L}$	(8a)
	${\pi }_L=\frac{x_0}{L}$	(8b)
	${\tau }_0=\frac{L^2}{2D}\frac{\frac{x_0}{L}\left(2-\frac{x_0}{L}\right)}{3}$	(8c)
	${\tau }_L=\frac{L^2}{2D}\frac{\left(1-\frac{x_0}{L}\right)\left(1+\frac{x_0}{L}\right)}{3}$	(8d)
	$\tau =\frac{L^2}{2D}\frac{x_0}{L}\left(1-\frac{x_0}{L}\right).$	(8e)