Abstract: A method for preparing a pyrotechnic composition which comprises preparing a composition in a gel form using nitrocellulose and a nitro compound other than nitrocellulose, adding an oxidizing agent, a combustible material and a color rendering agent to the composition, followed by mixing, forming the resultant mixture into a desired shape, and then drying; and a pyrotechnic composition obtainable by using the method. This method can be used for simplifying a production process while maintaining the effect of a star and a lance used in a pyrotechnic composition, particularly in a firework composition.

Abstract: A method for explosive cladding a metal surface with one or more layers of the same or different metal with a water-in-oil type emulsion explosive and an explosive clad metal composite comprising two or more layers of the same or different metal produced by explosive cladding with a water-in-oil type emulsion explosive.

Abstract: An apparatus for controlling intake air flow rate in an internal combustion engine comprises a throttle valve disposed in intake air passage for swing movement to change a flow rate of air to be supplied to combustion chambers of the engine, a stopper portion to which the throttle valve is abutted so as to stop swinging thereof in a full closed portion thereof, a spring for continually urging the throttle valve towards the full closed position, a control unit for determining a desired opening degree of the throttle valve in accordance with requirements on the engine, an actuator for generating a driving force for swinging the throttle valve to the desired opening degree in accordance with a command signal from the control unit, and geared mechanism for transmitting the driving force from the actuator to the throttle valve. The geared mechanism includes a pair of gears, each having a gear tooth portion. The gears are able to engage with each other exclusively at such gear tooth portions.