Fig. 7. Simplified schematic 2D picture of a 4 × 4 grid to illustrate the grid scheme used to calculate local temperatures according to eqn (9) where the Joule heat contribution depending on the local CNT density is added. Temperatures are evaluated on the grid vertices. Periodic boundary conditions are applied in all directions. For this reason grid points 1 and 4, 5 and 8, 9 and 12, 13 and 16, 2 and 14, 3 and 15 are equivalent.