Conjugate heat transfer in a closed volume with the local heat sources and non-uniform heat dissipation on the boundaries of heat conducting walls

Is solved the problem of heat transfer in the closed volume, limited by heat-conducting walls, with the local source of heat emission and the heterogeneous conditions of heat sink on the outer boundaries of solution area. The problem of convective heat transfer is solved with using a system of differential Navier-Stokes equations in the Boussinesq approximation. The simulation of turbulent flow conditions of heated air is carried out within the framework to k-ε model. On the basis the analysis of the obtained temperature field and the contour lines of stream functions is made conclusion about the essential transiency of the process in question. The obtained values of temperatures and speeds in different sections of region illustrate turbulence of the process. Are investigated laws governing the formation of temperature fields in closed areas with a local heat emission source under the conditions of intensive local heat sink into environment and accumulation of heat in the enclosing constructions

Flame fronts in Supernovae Ia and their pulsational stability

The structure of the deflagration burning front in type Ia supernovae is considered. The parameters of the flame are obtained: its normal velocity and thickness. The results are in good agreement with the previous works of different authors. The problem of pulsation instability of the flame, subject to plane perturbations, is studied. First, with the artificial system with switched-off hydrodynamics the possibility of secondary reactions to stabilize the front is shown. Second, with account of hydrodynamics, realistic EOS and thermal conduction we can obtain pulsations when Zeldovich number was artificially increased. The critical Zeldovich numbers are presented. These results show the stability of the flame in type Ia supernovae against pulsations because its effective Zeldovich number is small.Comment: 12 pages, 11 figure

The crisis of the communist party of the Soviet Union in 1990-1991 (according to the materials of the Novopolotsk committee of the CPSU)

The article presents the prerequisites for the crisis of the party-state apparatus of Novopolotsk, the main features and features of this process in 1990-1991. The conclusion is made about the regularity of the genesis of the problems, the escalation of tensions in accordance with the trends within the Byelorussian SSR, the connection between the rising crime rate and the decline in the standard of living and the loss of control over the management of the city

Analysis of influence of heat insulation on the thermal regime of storage tanks with liquefied natural gas

Is numerically investigated the process of convective heat transfer in the reservoirs of liquefied natural gas (LNG). The regimes of natural convection in a closed rectangular region with different intensity of heat exchange at the external borders are investigated. Is solved the time-dependent system of energy and Navier-Stokes equations in the dimensionless variables “vorticity – the stream function”. Are obtained distributions of the hydrodynamic parameters and temperatures, that characterize basic regularities of the processes. The special features of the formation of circulation flows are isolated and the analysis of the temperature distribution in the solution region is carried out. Is shown the influence of geometric characteristics and intensity of heat exchange on the outer boundaries of reservoir on the temperature field in the LNG storage

“No, not the Moon, but a Bright Dial...” (O. E. Mandelstam): Experience of Poetic-Ideographic Analysis

The principles of the formation of the author’s poetic ideography are highlighted — a new direction in the study of poetic texts, which is currently developing at the intersection of theoretical and practical ideography and author’s lexicography. The main goal of this approach is to identify and describe the individual author’s poetic pictures of the world and their representations in lexicographic parameters. Both the general model of the proposed poetic-ideographic analysis and the main theoretical concepts associated with the new cognitive-discursive approach to the interpretation of a poetic text are presented in the article. They are: a global individual-author’s worldview, a local picture of a fragment of the world, which in the dictionary have features their representation within the framework of various structures: integral global-event, local-fragmentary, macro- and micro-situational. They are used in the process of poetic-ideographic analysis of the poem “No, not the moon, but a bright dial...” (O. E. Mandelstam), carried out in the proposed article on the basis of the developed analysis model, its main stages, and tasks. The prospect of the research is the study of the integral individual-author’s worldview of O. E. Mandelstam, presented in the first edition of the book “Stone”, as well as the compilation of the author’s ideographic dictionary of the poet’s language

Importance of correlation effects in hcp iron revealed by a pressure-induced electronic topological transition

We discover that hcp phases of Fe and Fe0.9Ni0.1 undergo an electronic topological transition at pressures of about 40 GPa. This topological change of the Fermi surface manifests itself through anomalous behavior of the Debye sound velocity, c/a lattice parameter ratio and M\"ossbauer center shift observed in our experiments. First-principles simulations within the dynamic mean field approach demonstrate that the transition is induced by many-electron effects. It is absent in one-electron calculations and represents a clear signature of correlation effects in hcp Fe

Pressure-induced charge ordering transition in CaMn7O12

We use high-pressure resistivity and single crystal x-ray diffraction at ambient and low temperature to investigate the charge ordering phase transition of CaMn 7 O 12 . We have found that at ambient temperature the Jahn-Teller distortion of the Mn 3 + O 6 octahedra rapidly decreases above 20 GPa, and vanishes at 28 GPa, when two Mn octahedral sites initially occupied by Mn 3 + and Mn 4 + become regular and equivalent as the result of a charge delocalization. Such a change correlates with a two orders of magnitude drop in the resistivity and a symmetry increase from the low-pressure rhombohedral R ¯ 3 phase to the cubic Im ¯ 3 structure, the same as one found at ambient pressure above 440 K. This yields the slope of the charge ordering phase boundary of d T c / d p ? ? 6 K/GPa. This result is further supported by the lack of a structural phase transition up to the maximum measured pressure of 30 GPa when the experiment is performed at 70 K. The satellite reflections of the structural modulation of the multiferroic phase of CaMn 7 O 12 observed at 70 K were found to hold up to 25 GPa with the structure keeping a constant modulation vector k = ( 0 0 0.925 ) with pressure. The average structure at 70 K does not show other indications of further phase transition.Y. Li and X. Du from Peking University are greatly acknowledged for growing and providing the CaMn7O12 crystals. D. Spahr and J. König from Goethe University are acknowledged for help with the single-crystal diffraction experiments. M.S. would like to acknowledge the financial support under the DFG-ANR Grant No. WI1232/41-1 and DFG GACR Project No. WI3320/3-1. V.M. and J.R.-F. thank the financial support from the Spanish Ministerio de Ciencia e Innovación (MICINN) for the Beatriz Galindo Program (BG20/000777) and for the Project No. PGC2018-097520- A-I00, respectively. DESY Photon Science is gratefully acknowledged. PETRA III at DESY is a member of the Helmholtz Association (HGF)