2) In class we have been mainly discussing scenarios where the diffusion coefficient is isotropic, 1.e., direction independent. For many materials systems though, the diffusion process can be anisotropic, i.e., direction dependent. An example of this is the diffusion of nickel atoms in the mineral Olivine, i.e., magnesium-iron silicate. Olivine has an orthorhombic crystal structure and the typical arrangement of atoms in the material result in different values of the diffusivity along its different directions. Derive the form of the diffusion equation for this material, assuming diffusivities Dy, D,,, D, along its three principal directions. (10 points)