Develop the finite difference approximation of Fick's second law of diffusion in polar coordinates. Write a MATLAB program that can be used to solve the following problem: A wet cylinder of agar gel at 278 K with a uniform concentration of urea of 100 mol/m 3 has a diameter of 0.03 m and is 1.0 m long with flat parallel ends. The diffusivity is 5• 10 -1~ m2/s. Calculate the concentration at the midpoint of the cylinder after 100 h for the following cases if the cylinder is suddenly immersed in turbulent pure water. Since the cylinder is long, you may ignore axial diffusion.