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(1) An explosive with predetermined mass and form of placement that is laid in a charge cavity and equipped with a charge initiator. The main forms of a charge are concentrated charges (spherical, cubic, or similar shapes) and distributed charges (cylindrical or flat). Concentrated charges are placed in underground workings of large cross section, such as chambers or tunnels, and are called tunnel (chamber) charges. Distributed charges placed in boreholes are called well charges, and those placed in shot holes are called blasthole charges. Kettle charges, in which the explosive is placed in an artificially created “kettle” in the bottom of the well, are a variety of borehole and blasthole charges. One of the main characteristics of a charge, which determines the efficiency of the explosion, is its design, which was advanced by the use of so-called air gaps between the parts of the charge or between the charge and the walls of the charge cavity (developed and introduced in the USSR from 1937 to 1962). The development of charges with air gaps made possible the control of the explosion processes by reducing the initial pressure of the explosion gases, increasing the length of the impulse, and exciting secondary waves, which propagate through the precompressed solid medium.
Further improvements of explosive charges are produced by the use of several types of explosives in one charge chamber and the introduction of multipulse sequences with millisecond delays in the explosion of parts of the charge.
N. V. MEL’NIKOV and L. N. MARCHENKO
(2) A powder propellant charge is a certain amount of powdei required to propel a projectile (a bomb or bullet) in the barrel of a firearm (weapon) and to project it at a specific velocity. Powder charges are placed in shell cases or in separate small pouches (cartridges) and may be fixed or variable. The latter type, called a multisection charge, consists of several preweighed divided parts that make it possible to change the mass of the charge by separation of a certain part of it and thus vary the initial velocity of the projectile, the nature of the trajectory, and the range of fire. Powder charges are divided into combat charges, special charges designed for experimental firing during the testing of combat materiel and armament and for special types of firing practice, and blank charges, intended for reproducing the sound of firing.
(3) A solid-propellant grain is one or more units (burners or grains) of a solid fuel, with a certain geometrical form, that are placed in the engine chamber and create a reactive force that propels the rocket at a specific velocity in a certain direction when the products of combustion are discharged through the nozzle.
(4) An ejection charge is a specific amount of powder placed in a projectile, mine, or shell case and designed for ejecting destructive, incendiary, and illuminating elements from the ammunition shell.
(5) A shell (bursting) charge is an explosive placed in the body of a shell or bomb, the warhead of a rocket, or a hand grenade; it is designed to produce an explosion with destruction of the ammunition shell and projection of the broken fragments.
(6) A nuclear charge is a fissionable substance (isotopes of uranium-235, plutonium-239, and other elements) that is placed in the warhead of a rocket or aerial bomb; it is capable of a self-propagating fission chain reaction accompanied by the release of a large amount of energy in an extremely short period of time.
(7) A thermonuclear charge is a mixture mainly consisting of hydrogen isotopes that are capable of a nuclear fusion reaction with the release of an enormous amount of energy, considerably greater than the energy of nuclear fission.
IU. V. FEDOROV
REFERENCESAssonov, V. A. Vzryvnye raboty, 3rd ed. Moscow, 1958.
Mel’nikov, N. V., and L. N. Marchenko. Energiia vzryva i konstruktsiia zariada. Moscow, 1964.
Marchenko, L. N. Uvelichenie effektivnosti vzryva pri dobyvanii poleznykh iskopaemykh. Moscow, 1965.
Vzryvchatye veshchestva i porokha. Moscow, 1955.
Mikhailov, E. P. Podryvnoe delo. Moscow, 1963.
ladernoe oruzhie (Fizicheskie osnovy). Moscow, 1965.
Mikhailov, V. A., and I. A. Naumenko. Iadernaia fizika i iadernoe oruzhie. Moscow, 1966.