TY JOUR TI IMPROVEMENT OF COOLING EFFICIENCY OF FIRE CONTROL UNITS KW fire alarm KW heat pipe KW pulse heat pipe KW closed loop KW phase change JO Problems of risk management in the technosphere AU Kuzmina, T.A. AU Maer, O.M. AU Terekhin, S.N. PY 2026 IS 2025 PB Saint-Petersburg University of State Fire Service of Emercom of Russia