Abstract: A rotor of a gas turbine having two adjacent rotor discs, on each of which moving blades are fastened, an annular rotor component being arranged between the rotor discs and having at its opposite ends circumferential annular grooves, in each of which a circumferential fastening projection on the respective rotor disc engages. When the rotor is stationary a first outer flank of the first annular groove rests under pressure against a first outer flank of the first fastening projection and there is play between a first inner flank of the first annular groove and a first inner flank of the first fastening projection.

Abstract: A motorized firearm barrel cleaning system includes a main body containing an electric motor unit configured to generate sonic vibrations. An elongated rod is in communication with the motor unit for transferring the vibrations to a removable brush head having a shape and dimension for making contact with a firearm barrel.