  Although infinite cylinders are not astrophysical entities, it is possible to
learn a great deal about the basic qualitative features of generation of
gravitational waves and the behavior of the matter conforming such shells in
the limits of very small radius. We describe the analytical model using kinetic
theory for the matter and the junction conditions through the shell to obtain
its equation of motion. The nature of the static solutions are analyzed, both
for a single shell as well as for two concentric shells. In this second case,
for a time dependent external shell, we integrate numerically the equation of
motion for several values of the constants of the system. Also, a brief
description in terms of the Komar mass is given to account for the
gravitational wave energy emitted by the system.
