Abstract: A braking device has a portion having a braking surface adapted to come into contact with an opposite facing braking surface to apply a braking action, the braking surface being circumferentially free from obstacles to allow relative rotation between the braking surface and opposite facing braking surface when mutually in contact, and defining, in any point with respect to a revolution axis if the braking surface is fixed, or a rotation axis if the braking surface is rotative, an axial direction, a radial direction, a circumferential direction, and a tangential direction. A support connecting portion is radially outside the braking surface, either radially away from or outside the braking surface or either radially close to or inside the braking surface. A cooling portion, included circumferentially and laterally to the support connecting portion, has a plurality of axially through-openings adapted to increase a heat exchange surface and unadapted to create connecting surfaces.

Abstract: A watercraft (1) comprising a hull (2) and retention means (7, 10, 20, 20a, 20b) to connect a sea scooter (8) and said hull (2) together in such a manner that said sea scooter can at least contribute to the propulsion of said watercraft.

Abstract: A method for eliminating flying dust from an open space by spraying the flying dust with a jet of air carrying a number of atomized water droplets so that the atomized water droplets cause the flying dust to agglomerate and precipitate to the ground.

Abstract: A method for collecting and eliminating flying dust and for fire extinguishing use, characterised by spraying the space concerned by jets of air to which water and possibly surfactant have been added by injection into said jets.