O. N. Bodin1, V.M. Zhigachev2, U.N. Balaba3, I.V. Golubkova4

1–4 Penza State Technological University (Penza, Russia)
1 bodin_o@inbox.ru, 2 zhigachevvm@mail.ru, 3 balabaul2017@gmail.com, 4 ilonna1990@mail.ru