TY JOUR TI JUSTIFICATION OF THE MECHANISM OF THE FIRE EXTINGUISHING ACTION OF THE POWDER BASED ON AN ANALYSIS OF ITS FRACTIONAL COMPOSITION IN A NON-STATIONARY GAS-POWDER FLOW KW fractional composition KW fire extinguishing powder composition KW heat absorption power KW powder extinguishing effect JO Problems of risk management in the technosphere AU Kozhevin, D.F. PY 2025 IS 2025 PB Saint-Petersburg University of State Fire Service of Emercom of Russia