  In this paper we are giving a quantitative description of two different
configurations for noncontact gears. We consider the solutions from a
perturbative calculation for two semitransparent parallel plates and concentric
cylinders both with corrugations on the inner surfaces. In the case of
corrugated parallel plates we discuss results from first- and second-order
perturbation calculation in the corrugation amplitudes and we will concentrate
on the first-order perturbation for the case of the corrugated concentric
cylinders (the second order calculation is under study), both for the weak and
strong couplings. We compare the perturbative results with the results from the
PFA and an exact weak coupling calculation.
