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Based on a system of gas dynamics equations for a mixture of vibrationally excited chemically reacting molecular gases, the effect of a carbon dioxide additive on the stability of a hypersonic boundary layer of neutral nitrogen on a plate was studied. Calculations were performed for five mixture composition variants. Steady-state flow parameters were calculated using a locally self-similar approximation of the boundary layer equations. Within the framework of linear stability theory, the dependences of the critical Reynolds numbers Re_δc and the laminar-turbulent transition Reynolds numbers Re_xT* on the molar concentration of the additive were obtained. In particular, for a 50% mixture, the relative increase in both criteria compared to the corresponding values for a mixture of perfect gases is approximately 53%. Moreover, the contribution of CO₂ dissociation to the shift of the laminar-turbulent transition zone is twice as great as the contribution of vibrational mode relaxation. It is shown that the obtained dependence ofRe_xT* on the molar concentration of the additive correlates with the corresponding experimental results of Professor H. Hornung's group.

This paper considers a relation between the emissivity of metals from the V period of the Periodic System while melting process with thermophysical properties: surface tension coefficient (γ) and specific heat capacity (C_p). Taking the own and available experimental data and using the theoretical calculation within Foot’s approximation, we elucidated the laws of emissivity as a function of electronic stricture and interatomic interaction. It was demonstrated that a correlation between the emissivity and γ and C_p has a complicated behavior and this is dictated by general trends (emissivity increases with γ) and by a specific electron configuration for given elements. The results underline the importance of considering the periodicity and electronic configuration in forecasting the thermophysical properties of metals in the phase transition state.

The results of an experimental study of the influence of tabs (teeth) of various shapes on the intensity of turbulent heat transfer in the separation zone in the near wake of a backward-facing step are presented. In this stagnation region, a significant decrease in heat transfer is observed, which negatively affects the thermal-hydraulic efficiency. Five tab shapes were studied in the experiments: square, triangular, cylindrical, semi-cylindrical, and semi-conical ones. The tabs were installed at the step edge immediately before flow separation. Measurements were conducted at Reynolds number Re_Н = 4000 and varying tab pitch. It was found that square tabs with a pitch of 2.5 calibers (step height) have the greatest effect on flow and heat transfer, but at the same time, they cause the greatest hydraulic resistance, therefore, their thermal-hydraulic efficiency is lowest. Semi-conical tabs installed with a pitch of five calibers showed the best results.

Ground-based simulation of processes around space vehicles in open space is a topical issue for rocket industry. Some problems can be covered by middle-size vacuum-based gas-dynamic setups; they provide model flow regimes for imitation of natural regimes befitting from low financial and material costs. The updates for the laboratory vacuum setup LAMPUS-2 based in Novosibirsk State University and improvements in gas dynamic diagnostic tools enabled a wide range of study for supersonic jets emerging from a nozzle cluster. This paper presents the measurement results performed for binary cluster jets using photo visualization method and scanning of argon flows for different ratio of stagnation pressure to the ambient pressure. The process of condensation has a significant influence on the dynamics of interacting jets.

The development of optoelectronic methods for measuring through a multiphase barrier in the study of a dispersed component in experiments on modeling the natural and technical hydrodynamic systems is a pressing issue. The difficulties of direct measurements under hurricane conditions necessitate laboratory measurements. Spray formation was studied in detail during the laboratory experiments in the high-speed wind-wave channel (WWC) at the Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS). A modern, non-contact optical method for diagnosing two-phase flows-laser Doppler anemometry (LDA)-was used to measure the kinematic characteristics of the aerosol flow. Experiments were carried out to measure the aerosol droplet aerodynamics in WWC of IAP RAS. It was demonstrated that the measuring system enables to measure all three components of the aerodynamic flow velocity through a multiphase barrier at wind speeds from 10 to 40 m/s over a wide range of conditions. The results of measurements were compared with the readings of the Pitot tube, and good agreement and reproducibility of the experimental results were shown.

A method to synthesis new hybrid derivatives of α-pinene with α-aminophosphonate fragment has been developed to obtain an additional centre of metal coordination in the molecules of potential extractants for heavy metals. It has been shown that O-alkyl ethers of α-amino oximes of the pinane series can be converted according to the two-stage version of Kabachnik-Fields reaction with dimethylphosphite and benzaldehyde into new chiral α-aminophosphonates with a satisfactory preparative yield (40-42 %). According to this scheme, terpene aminophosphonates are obtained as highly lipophilic products in the form of a pair of stereoisomers with a diastereomeric purity of 49-66 %.

A method for modifying nopinane-annelated 4,5-diazafluorene by introducing butyl groups and an additional amide group is proposed. Stereoselectivity of the formation of a single isomer by the substitution of a benzyl methylene group of pinane system is demonstrated. The structure of the new substances is established using a set of physicochemical methods. The synthesised substances can be promising tridentate ligands and extractants for d- and f-elements.

Triarylmethyl radicals (TAM, trityls) presented in the form of water-soluble tricarboxylic acids are widely used in biomedical, chemical and spectroscopic studies. In most applications, trityl radicals demonstrate high stability against various redox agents. An exception is the oxidative degradation of TAM to diamagnetic quinone methides. A typical active form of oxygen in biological environments, superoxide (O₂^·- or HO₂^·) is involved in this reaction. The details of this process have been studied in order to identify the factors controlling the channel of TAM consumption. The study has been performed using quantum chemical calculations (by means of the density functional theory) on a model trityl - triphenylmethyl radical presented in the form of a monocarboxylic acid. Alternative routes differing in the nature of protonation of key reagents in the aqueous medium have been considered. It has been established that protonation/deprotonation of reagents controls the barrier of the rate-limiting stage and, thus, the rate of the observed decarboxylation. This conclusion is in good agreement with the experimental data on the dependence of the reaction rate on pH. Among the reaction pathways considered, the most favourable one is the interaction of TAM anion, containing deprotonated carboxyl group, with protonated superoxide (neutral hydroperoxide radical HO₂^·). Taking into account the identified features, an analysis of alternative oxidation routes of another TAM derivative was carried out, for which the role of the key stage is assigned to proton elimination.

The reaction of 2-R-5,5-diethyl-2-ethynylpyrrolidin-1-oxyls (where R = Et, i-Pr) with esters of azidoacetic and p-azidobenzoic acids in the presence of copper(I) salts has been studied. It was found that the presence of the bulky isopropyl substituent prevents the reaction with ethyl ether of p-azidobenzoic acid and decreases the yield of the corresponding triazole in the reaction with methyl ester of azidoacetic acid. The resulting nitroxides demonstrated a high degree of resistance to reduction by ascorbic acid, which was comparable to the stability of 3,4-bis-hydroxymethyl-2,2,5,5-tetraethylpyrrolidin-1-oxyl.

Results obtained in the studies of living systems using chemical fingerprinting methodology are presented. Gas chromatography - mass spectrometry and the tools of chemical fingerprinting were applied to obtain the chromatographic profiles and to determine the isomeric-homologous series of characteristic target metabolites of various classes of the objects of plant origin and cuticular lipids of insects at different stages of ontogenesis and living in different climatic conditions. The main target metabolites considered herein are hydrocarbons, ketones, alcohols, fatty acids and their hydroxy-derivatives, esters, alkylresorcinols, di- and triterpenoids, phenol acids, and lignans. The approach used in the work makes it possible to establish the composition of characteristic target metabolites in various living systems and their changes in the processes occurring under the influence of abiotic and biotic factors, targeted gene mutations, which can be used both in fundamental and applied research, including the improvement of approaches to biological control of economically important insect pests in agriculture.