Cocondensation of the (het)aromatic aldehydes (I) with butyraldehyde (II) in the presence of urea (III) and a Co(II)/triethylaluminum catalytic system gives the (het)arylpyridines (IV), together with the diethylpropylpyridine (V).

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This article is devoted to the development of a sliding burnishing scheme using a flat cylindrical indenter. The previously established patterns of nanostructured state formation in the AISI 52100 steel subsurface layer showed a need to create a special tool with a variable tilt angle of the indenter and with force regulation. A new tool with a cubic boron nitride indenter opens wide possibilities for nanostructuring burnishing of hardened bearing steel. Firstly, a flat cylindrical indenter has high durability due to repeated rotation around its axis. Secondly, the change of the tilt angle to the treated surface allows controlling the contact compression pressure and plastic shear deformation, which determines the formation of a nanostructured state of the material by the method of severe plastic deformation (SPD). The purpose of the work is to determine the optimal parameters of the process and tool in order to form a nanostructure and significantly increase surface layer microhardness. The goal was achieved by the methods of finite element modeling (FEM) and experimental studies of burnishing when the indenter tilt angle changes from 0.5° to 2.5° under dry processing conditions. Numerical simulation of the process made it possible to establish optimal values of the indenter tilt angle of 2° and the burnishing force 250 N according to the criteria of maximum contact pressure and cumulative deformation. The experimental studies of cumulative deformations and the coefficient of friction by the method of burnishing a split disc and dynamometry of the process confirmed the FEM results. The transmission microscopy, durometry, and 3D surface profilometry showed the sensitivity of nanocrystallite sizes, microhardness, and roughness to an indenter tilt angle and confirmed the optimality of the established tilt angle value.

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Stress and strain distributions in the Yakutsk-Vilyui large igneous province (LIP) are numerically simulated under geotectonic extension. A two-dimensional model of the geological structure of a part of the Yakutsk-Vilyui LIP is developed using the geophysical data from the profile “Craton-1980”. However, these geophysical data can only be a source of the geometrical model and elastic properties of Earth’s layers. To describe non-elastic strains during the geological process, the Drucker-Prager-Nikolaevsky model of plasticity is adopted. For elastoplastic analysis of the geotectonic process, the “Jelly Sandwich” shear strength model for the continental lithosphere is used, which is based on the variation of the strength properties with depth. Zones of shear stress concentration and plastic strain localization are observed as a result of the extension in the Lindenskaya basin and Khapchagaiskaya reclamation complying with oil and gas deposit locations in the Yakutia region. Stress components have non-linear distributions determined by the dependence of strength properties on the depth and structural inhomogeneity of continental lithosphere. The pressure distribution obtained in the simulation can partially complement the geological information employed when analyzing the possibility of phase transitions in the rocks in different locations of the studied region.