A semiconductor switching device is formed on a semiconductor substrate having a trench formed on one of its surfaces. The auxiliary system of the present invention sends data and control signals between an underwater installation\u2014for example, a lower stack 26 in a hydrocarbon drilling or production facility\u2014and an associated riser assembly 23. The article pushers are carried by a movable support plate between retracted positions behind the cutter blades and extended positions over the cutter blades. A charging circuit is operative to generate an electrostatic charge so that the brake dust is attracted to the charged collector plate.