S.A. Kravtsov - Post-graduate Student, P.G. Demidov Yaroslavl State University. E-mail: sk860@outlook.com A.I. Topnikov - Ph. D. (Eng.), Assistant, P.G. Demidov Yaroslavl State University. E-mail: topartgroup@gmail.com A.L. Priorov - Dr. Sc. (Eng.), Associate Professor, P.G. Demidov Yaroslavl State University. E-mail: andcat@yandex.ru