Abstract: A protective system for dentist chill units including a protective element and a sealing substance around the drill to prevent the entrance of undesirable matter such as the HIV (AIDS) virus into the handpiece holding the drill, which may, when the drill is replaced by another drill, infect the next patient, the system including an optional device including at least one valve for preventing undesirable matter such as the HIV virus from remaining in the water system after possible entry through one or more water nozzles in the handpiece, once the water is pumped out and possibly replaced by disinfectant, and then again with cooling water.

Abstract: A firearm for firing cartridges (2) which may in at least one embodiment fire caseless cartridges (2), having a barrel (1) pivoting around a pivot point (11) from a firing position to a loading position, and back to the firing position. A fixed wall (16) is positioned behind chamber (19) when barrel (1) is in the firing position, which absorbs the recoil of a fired cartridge (2). A plug (6) may be used to seal chamber (19) when firing caseless cartridges (2). The pivoting movement of barrel (1) may be activated against spring (4) by gas pressure from a fired cartridge (2) escaping from a hole (3) in barrel (1). Residual gas in barrel (1) may be used to move rammer (7) against spring (8) and rammer (7) then chambers a cartridge (2). Barrel (1) then returns to the firing position.

Abstract: The present invention provides a screen for limiting the amount of light entering a camera lens through a sunshade. To this end, a camera which may be a film or video camera with interchangeable or fixed focal length lenses or interchangeable or fixed zoom lenses and which includes a sunshade having a fixed opening mounted to the lens is provided with an axially adjustable mask within the sunshade. The mask may be mounted at either the front or the rear opening of a bellows which is of the accordion-type. Positioning of the mask may be through a gear mechanism including a rack extending through an opening in the sunshade or may be through a slide mechanism external of the sunshade and passing internally thereof through a light sealed slot.

Abstract: This invention provides a process for obtaining substantially pure manganese metal by the reduction of a manganese oxide or a manganese halide by reaction with a subhalide of a transport metal. The transport metal can be aluminum, silicon, or titanium. In preferred embodiments of this procedure, a continuous closed cycle process is carried out wherein the transport metal value is reconverted to its subhalide and recycled for reaction with additional manganese compound.