Albert Katunin

A model is constructed that mathematically describes the rise to the water surface of an explosive object made of ferromagnetic material by means of an electromagnet in the form of a solenoid on a core of ferromagnetic material. Taking into account that the magnetic permeability of water is close to unity, and water slightly weakens the magnetic field that passes through it, it is shown that the water environment does not significantly affect the magnetic properties of the electromagnet under the conditions of its proper waterproofing. It is shown that the magnitude of magnetic induction required to lift an object made of ferromagnetic material depends on the area of the working surface of the electromagnet according to a law close to hyperbolic. Explosive objects made of ferromagnetic materials can be removed from water using electromagnets with a certain parameter . The developed model shows that the parameter is a function of the square root of the mass of the object being lifted and is inversely proportional to the diameter of the electromagnet core. To lift explosive objects weighing up to 100 kg, a core made of a material with a high magnetic permeability and a high winding density of the electromagnet winding are required. The magnetic induction at a distance r from the working surface of an electromagnet of radius R varies according to the law R ³ /(R ² +r ² ) ^3/2 . It is proved by calculation that with an increase in the diameter of the electromagnet core, the magnetic induction decreases more slowly with distance from it. The results obtained are the scientific basis for engineering and design work in the development of new methods and devices for underwater humanitarian demining.

The work investigates the effect of additives to the primary material of a current-carrying conductor on the heating temperature of an electrical wire, exemplified by a single-core aluminium wire with single-layer polyvinyl chloride insulation. It establishes the dependencies between the wire's heating temperature and its operating time under load currents that are lower, close to, and higher than the permissible levels set by regulations. The effect of chromium, vanadium, and titanium additives to the primary material of a current-carrying conductor on the wire's heating temperature during operation is also evaluated. Even small amounts of additives (less than 0.1%) to the primary material of a current-carrying conductor can affect the heating temperature of the loaded wire. Chromium additives have the most effect, while titanium additives have the least effect. The study demonstrates that during operation, a loaded electrical wire heats the least if the primary material of its current-carrying conductor has none of the additives considered in the article.