  We conduct experiments and simulations to study the disordered packing of
rods in small containers. Experiments study cylindrical rods with aspect ratio
ranging from 4 to 32; simulations use of spherocylinders with similar aspect
ratios. In all cases, rods pack randomly in cylindrical containers whose
smallest dimension is larger than the rod length. Packings in smaller
containers have lower volume fractions than those in larger containers,
demonstrating the influence of the boundaries. The volume fraction extrapolated
to infinite container size decreases with increasing aspect ratio, in agreement
with previous work. X-ray tomography experiments show that the boundary effects
depend on the orientation of the boundary, indicating a strong influence of
gravity, whereas the simulation finds boundary effects that are purely
geometric. In all cases, the boundary influence extends approximately half a
particle length into the interior of the container.
