Abstract: A diffuser which includes a cylinder open at one end and closed at the opposite end, the open end of the cylinder being securable to air supply; the wall of the diffuser being formed with a plurality of holes therethrough, each hole having a larger diameter on the exterior of the wall of the diffuser than on the interior of the wall of the diffuser, the longitudinal axis of each hole being inclined at an acute angle to both the radius and the longitudinal axis of the diffuser, and the orientation of each hole with respect to the longitudinal axis of the diffuser being such that when the diffuser is rotated about it longitudinal axis in use, the leading edge of each hole is at a higher elevation than the trailing edge of each hole.

Abstract: A self-powered mobile platform that is configured to be remotely wirelessly controlled, said platform including a base with a first face that is dimensioned and configured to allow a vertical landing aircraft to land and take off.

Abstract: An aerator/mixer which includes a rotatable hollow drive shaft one or more air intake ports adjacent one end, and a propeller and an air permeable diffuser mounted adjacent to the other end; the diffuser is mounted below the propeller; and is in communication with the interior of the hollow drive shaft such that air supplied to the air intake port can exit only through the diffuser, the aerator/mixer further includes a device for rotating the drive shaft and the propeller and a device for supplying air at above atmospheric pressure to the or each air intake port.

Abstract: An aerator/mixer which includes a rotatable hollow drive shaft one or more air intake ports adjacent one end, and a propeller and an air permeable diffuser mounted adjacent to the other end; the diffuser is mounted below the propeller; and is in communication with the interior of the hollow drive shaft such that air supplied to the air intake port can exit only through the diffuser, the aerator/mixer further includes means for rotating the drive shaft and the propeller and means for supplying air at above atmospheric pressure to the or each air intake port.