TY JOUR TI ACOUSTIC ULTRASONIC HARDNESS TESTER KW ultrasound KW hardness measurement KW hardness KW acoustic methods KW the method of natural-model tests JO Alternative energy sources in the transport-technological complex: problems and prospects of rational use of AU Kovalev, I.. AU Lankin, A.. AU Baklanov, A.. AU Kazaryan, A.. PY 2015 IS 2 PB FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov