Abstract: A buccal tube contains a rotating integral cover attachable over the archwire slot of the tube.

Abstract: A portable martial arts device for rigidly holding one or more boards to receive a karate blow or the like. The device comprises a freestanding framework and a board holder mounted on the framework for rigidly holding parallel edge margins of one or more boards thereby to position the boards for receiving a karate blow or the like. A mechanism is provided for mounting the board holder on the framework for pivotal movement about a generally horizontal axis thereby to permit adjustment of the angular position of one or more boards in the holder. The framework is adapted for adjustment of the height of the board holder, thereby permitting adjustment of the height of boards in the holder.

Abstract: A process for economical air drying of aqueous sludge, and a vehicle which may be used in practicing such process. The surface of a pool of sludge, such as in a sludge lagoon, is systematically agitated to break up the dry crust and to bring wet sludge to the surface for more rapid removal of water by evaporation and to form a dry upper layer of substantial thickness. The drier surface material is skimmed off the surface and either harvested directly or shifted laterally to provide an inclined surface on the lagoon so as to facilitate drainage of surface water, such as from precipitation. The dry surface sludge is harvested from the lagoon either after systematic shifting of the dry surface sludge to one side of the lagoon, or by transporting of the dry sludge through a conduit to the side of the lagoon, or by loading of the sludge into a receptacle of a stirring/harvesting vehicle for periodic delivery to the side of the lagoon.

Abstract: A hydraulic screw pump is provided having a rotatable screw which may comprise a helical blade disposed within an enclosed full or open half cylinder. In half-cylindrical constructions the helical blade rotates relative to a half cylinder which may be formed of concrete. The enclosed screw pumps may have the helical blades welded to the inner periphery of a surrounding metal cylinder so as to rotate therewith, or be welded to said surrounding metal cylinder and also to an inner cylinder which provides axial reinforcement.In all of the foregoing pump embodiments the improvement of this invention may be utilized to provide increased pump capacity by the novel expedient of flaring the pump discharge end so as to increase the critical depth and critical flow area in said discharge end thus increasing the possible maximum rate of liquid discharge.

Abstract: Method and apparatus for automatically controlled conducting of liquid downward through a gravity-flow subatmospheric-pressure shaft over a wide range of flow rates by use of a movable float-operated inlet valve with variable upward force being applied to the movable valve assembly to compensate for the variable downward forces resulting from the development of a partial vacuum in the flow shaft.

Abstract: Apparatus for achieving liquid flow at constant discharge rate from a liquid reservoir wherein the surface of liquid therein fluctuates in elevation.

Abstract: Sewage is subjected to a sudden pressure release to break up the organic solids particles for improving subsequent treatment or separation operations.