МATHEMATICS Bazhenov D.S. Rings with a bounded graded index of nilpotency ............................................... 5 Bondarchuk I.S., Gerasimchuk A.L., Glukhova L.B., Marchenko E.S., Kychkin A.A., Kychkin A.K. A study of kinetic characteristics of biocidal action of copper oxide nanoparticles during climatic destruction and biocorrosion under extreme conditions of cold climate ...................................................................................................................... 13 Maiyer F.F., Tastanov M.G., Utemissova A.A. Estimates of analytical functions whose ranges of values are contained in a circular lune ................................................................... 28 Senashov V.I. A criterion of nonsimplicity of a group with a finite element ............................. 44 MECHANICS Azarov D.A. Formulation of constitutive relations for nonlinear elastic media using a mechanical–geometric model with diagonal bonds ............................................................ 51 Arkhipov V.A., Basalaev S.A., Perfil’eva K.G., Poryazov V.A. Method and results of an experimental study of heat losses in a combustion chamber of a solid-propellant propulsion system ................................................................................................................. 62 Borzenko E.I., Garbuzov D.N., Efremov M.A. Numerical modeling of non-newtonian fluid flows in an apparatus with blade mixers ....................................................................... 70 Valiullina V.I., Galeev R.R., Zinnatullin R.R., Musin A.A., Kovaleva L.A. Impact of the electromagnetic field on the properties of porous materials containing complex colloidal mixtures of organic compounds ............................................................................. 84 Valikhov V.D., Khrustalyov A.P., Zhukov I.A., Vorozhtsov A.B. Effect of basalt fibers on the structure and mechanical properties of AK12 aluminum alloy ........................ 97 Larkin D.O., Eremin I.V. Investigation of a two-phase flow in the nozzles of solidpropellant rockets ................................................................................................................ 108 Min’kov L.L., Gimaeva N.R., Dil’ D.V. Numerical study of the transition to a steady-state operating mode of a nozzleless propulsion system with a viscoelastic cylindrical charge ......................................................................................... 120 Pavlov M.S., Pavlyuk Yu.A., Pyshnograi G.V. Effect of rheologocal properties of polymer melts on kinematics of their flows in converging channeles ............................ 136 Starchenko A.V., Danilkin E.A., Leshchinskiy D.V. Numerical simulation of the solar radiation effect on the aerodynamics, heat exchange, and pollution transfer in a street canyon ................................................................................................... 151 Shablovskiy O.N. Unstable perturbations in a swirling flow of an ideal incompressible fluid in the regions with open boundaries ........................................................................... 166