Nonequilibrium processes in meta-stable media⋆.

Meta-stable systems are those staying in the local equilibrium state: being slightly deviated from it they return to the equilibrium, but in case deviation surpasses a critical value those systems fall down to another equilibrium state. Chemically reacting gaseous mixture provides a typical example of a meta-stable system. The paper is aimed at numerical and experimental investigation of detonation initiation in hydrogen-air mixtures due to focusing of a shock wave reflected inside a wedge. Both numerical and experimental investigations were conducted. Comparison of numerical and experimental results made it possible to validate the developed 3D transient mathematical model of chemically reacting gas mixture flows incorporating hydrogen-air mixtures. Kinetic schemes and turbulence models were improved based on comparison of numerical and experimental results. Several different flow scenarios manifest in the reflection of shock waves all being dependent on the incident shock wave intensity: reflection of the shock wave with lagging behind the combustion zone, formation of a detonation wave in reflection and focusing, and intermediate transient regimes.

Infection evolution and spreading models in non-uniform biological systems.

The paper investigates peculiarities of infection evolution and spreading models in non-uniform biological systems of individuals (humans, animals, plants) using the approach of mathematical modeling. The effects of different characteristic features are revealed. A robust tool for prediction of infection evolution (growth and spreading) under different external conditions is developed accounting for spatial non-uniformity of governing parameters.

[The choice of the radiation parameters in the laser reconstruction of the pupil]. / K vyboru parametrov izlucheniia pri lazernoi rekonstruktsii zrachkovogo otverstiia.

The phenomenon of a "local punch" of tissues in the zone of nano- or picosecond impulses of neodymium: YAG-laser radiation focusing allows to increase energy in the pulse by one order as compared with traditionally used energy. At this, in order to achieve the initial effect it becomes possible to reduce the number of shots by two orders and thus to increase the spot of radiation. The summary energy of action absorbed in the eye remains the same and that's why the number of complications doesn't increase. The widening of possibilities to choose a laser source for micro- and macroperforations allows, when prescribing the treatment, to more reliably consider clinical peculiarities in each concrete case.