Nanotube atom-count estimate
= Nanotube atom-count estimate
An area-based estimate treating each nanotube shell as a <graphene> cylinder. For <graphene> atomic area density $n_s$ and shell radii $r_j$, the carbon count per axial length is $N_C/\ell=2\pi n_s\sum_jr_j$. Defects and partial shells change the estimate.