Abstract: A lighting apparatus for controlling a plant disease is provided to reliably inhibit a spore formation and a hyphal growth of a filamentous fungi, reliably induce a disease resistance, prevent a leaf scorch, and promote a growth of a plant. A UV light source repeats a light irradiation which has an irradiation pattern of combining a light irradiation, in which UV-C and UV-B and a visible light are superimposed, with a visible light irradiation alone at least twice a day. The emission of UV-B and UV-C enables the reliable inhibition of the spore formation of the filamentous fungi, for example. Its intermittent emission prevents a plant from getting too used to ultraviolet rays, promotes a generation of an antibacterial substance, for example, and prevents a leaf scorch. The continuous emission of the visible light enables a promotion of a growth of the plant.

Abstract: A lighting apparatus for controlling a plant disease is provided to reliably inhibit a spore formation and a hyphal growth of a filamentous fungi, reliably induce a disease resistance, prevent a leaf scorch, and promote a growth of a plant. A UV light source repeats a light irradiation which has an irradiation pattern of combining a light irradiation, in which UV-C and UV-B and a visible light are superimposed, with a visible light irradiation alone at least twice a day. The emission of UV-B and UV-C enables the reliable inhibition of the spore formation of the filamentous fungi, for example. Its intermittent emission prevents a plant from getting too used to ultraviolet rays, promotes a generation of an antibacterial substance, for example, and prevents a leaf scorch. The continuous emission of the visible light enables a promotion of a growth of the plant.

Abstract: An electrostatic precipitator for removing fine particles from gas is described. The precipitator includes an array of dust collection pipes, each negatively charged and serving as an electrode. Each pipe has a pin-like positively charged discharge electrode centrally located within it. Mist-laden gas is caused to flow through the pipes and is electrostatically cleaned. A slit is formed in the pipes to permit some cleaned gas to be mixed with uncleaned gas and reintroduced into the pipes to reduce the density of the fine particles in the gas entering the pipes. The pipes may be vertically or horizontally arranged.

Abstract: A drill and trimming attachment assembly is disclosed for drilling holes with beveled top openings in a work piece. The assembly includes a drill shaft with at least one longitudinally extending groove formed therein. A trimming attachment suitable for clamping to the drill shaft is also provided to form a beveled recess at the top of a hole formed by the drill. The trimming attachment includes a body and a trimming blade having base and arm portions. The base portion of the trimming blade is detachably secured to the body, and the body is arranged to be removably journaled about and clamped to the shaft of the drill such that an edge of the arm portion of the trimming blade is closely received by the groove. Thus, during use, the groove carries at least a portion of the load acting against the trimming blade.

Abstract: A hole cutter having a generally cylindrical cutter body provided around its lower end with a plurality of first cutting teeth each having a plurality of cutting edges, and a plurality of second cutting teeth adapted to scrape a surface cut by the first cutting teeth.

Abstract: In a reduction gear apparatus consisting of a pair of planetary gears rotatably mounted on an input shaft, and a plurality of internal gears positioned within a casing so as to engage with said planetary gears, an output shaft rotatably mounted to said casing is rotated at two different reduction ratios by selectively fixing said internal gears to said casing.