In a steam turbine, a combined brush and labyrinth seal is provided between a diaphragm web and a sealing surface on a rotatable component radially outwardly of the rotor surface. This including a housing adapted for removable connection to cribs, changing tables and similar furniture, an ultraviolet light source in the housing for sanitizing items in the housing when closed and the ambient when opened, audio source and compartments for holding and storing select items. The edges 84A to 84D of the rod integrator can be prevented from being broken by coming into contact with the inner faces 66A to 66D of the case 61, and the edges 84A to 84D of the rod integrator 8 and the inner faces 66A to 66D of the case 61 can be prevented from rubbing against each other to generate dust due to abrasion. In a first embodiment the fret is comprised of magnetic material. A preferred embodiment of the dental radiography positioning system comprises an aimer ring that slides onto either a posterior imaging or an anterior imaging bar.