An electronic circuit including semiconductor modules and capacitors is positioned in the axial direction of a motor. A BD playback device is provided with an interactive content decision unit for analyzing control data received from a disc reader and determining whether a disc contains interactive content, and, if there is content, whether the interactive content should be played back. A plurality of fan blades are also connected to the shaft. The host computer loads the operating system in the portable apparatus into its random access semiconductor memory through the established connected-state operation. The compactness and functionality allows expansion joints for all types of piping and ducting and is particularly suitable for making expansion joints for piping and ducting with a diameter greater than 2 meters. Differential pressure causes the flow of a treatment fluid through the filter cake.