Abstract: A stratospheric airship capable of substantially and smoothly varying the volume of a buoyant gas is provided so as to allow the airship to stably ascend into the stratosphere and keep a station therein. A stratospheric airship includes a gas envelope defined by a ship hull, the gas envelope being divided by a diaphragm into a buoyant gas compartment containing a buoyant gas and an air compartment containing air, the stratospheric airship being allowed to ascend by varying the volume ratio between the buoyant gas and the air, wherein the periphery of the diaphragm is coupled to the ship hull generally at the midpoint along the vertical dimension thereof, and a central portion of the diaphragm is coupled to a suspension chord whose upper and lower ends are coupled respectively to the upper and lower surfaces of the ship hull. The sloshing phenomenon of the diaphragm is suppressed, whereby the change in the shape thereof is balanced, and thus there is no asymmetric distribution of the buoyant gas.

Abstract: A vacuum cleaner for cleaning floors or carpets, having a suction mouth (6), a base plate (5), which encloses the suction mouth (6), and a suction line, electrostatic charging of parts of the vacuum cleaner being provided in order to assist the dust uptake. In order advantageously to provide the vacuum cleaner with the dust uptake being assisted by electrostatic charging, the base plate (5) is electrostatically charged, and the electrostatic charging is carried out by a separate generator (8) provided in the vacuum cleaner.