The activation energy for the diffusion of atomic species A in metal B is 124 kJ/mol. Calculate the diffusion coefficient at 802°C, given that the value of D at 1150°C is 7.7 × 10-12 m2/s.

On solidification from a melt, the polymer polyethylene forms a semi-crystalline spherulite structure. (i) sketch an individual spherulite and label the amorphous and crystalline regions. (ii) draw a schematic to show the changes in specific volume with temperature during cooling from the melt, comparing it to the theoretical extremes of fully crystalline and fully amorphous (indicate tm and tg)