TY JOUR TI Mathematical description of the stages of thermal expansion of pyrolysis waste wooden sleepers KW wooden sleepers KW drying KW pyrolysis KW condensation JO Actual directions of scientific researches of the XXI century: theory and practice AU Savelev, A.. AU Khayrullina, E.. AU Khayrullina, M.. AU Tuntsev, D.. AU Romancheva, I.. PY 2015 IS 3 PB FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov