2. Carbon diffusion between two bars Two iron ingots containing different levels of dissolved carbon were fused together at plane x=0, in a similar fashion to that shown in the figure below. Assuming a general solution for the carbon concentration of the form: CA,x,t=A+Berf(4Dtx) write the appropriate boundary conditions to obtain an exact solution for the above example. If one cylinder contains 0.2%C and the other 0.05%C, what is the concentration of carbon at x=0 at time t ? Write down an expression for the mass flux of carbon at x=0, at time t. (b) (c)