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Lake Baikal is a unique freshwater environment with maximum depths over 1600m. The high water pressure at the lakebed strengthens the solidifying effect of low water temperature on animal tissue lipids, and thus the effective temperatures in the depths of the lake equal subzero temperatures in shallow waters. Cottoidei species has colonized the different water layers of the lake, and developed different ecology and physiology reflected in their tissue biochemistry. We studied by gas chromatography the composition of fatty acids (FAs), largely responsible for tissue lipid physical properties, in the white muscle tissue of 13 species of the Cottoidei fish; 5 benthic abyssal, 6 benthic eurybathic and 2 benthopelagic species. The FA profiles reflected habitat depth. The muscles of the deepest living species contained little polyunsaturated FAs (PUFAs) and were instead rich in monounsaturated FAs (MUFAs), which may be due to occasional weak food web links to the PUFA-rich primary producers of the photic water layer, high MUFA supply from their benthic diet, and conversion of saturated FAs (SFAs) to MUFAs in the tissues of the fish. Despite the MUFA percentage among the abyssal species reached even 50 % (by weight) of total FAs, the PUFA percentage still remained above 20% in every species. The muscle MUFA/SFA ratio correlated negatively with the PUFA content of the fish muscle, suggesting viscosity control integrating the fluidity contributions from the dietary PUFAs and potentially endogenous MUFAs.

The research is devoted to the analysis of available and widely used conventional measures to ensure reliable operation of the in-situ reinforced concrete structures and their compliance with legal requirements. It requires using one of the research trends of the Samara school of material sciences developed by the authors some time ago. Several stages of the work have been distinguished during the process of defining methodological foundations for effective non-destructive methods. The first stage concerned the proper mathematical apparatus of the concrete deterioration under various types of external effects. The second stage is important for determining the composition of basic physical and mechanical characteristics. Finally, the third stage is the period when the most reliable existing non-destructive methods are identified and investigation on new techniques is carried out. Thus, the combination of the A.A. Griffiths energy theory and the kinetic theory of S.N. Zhurkov has led to the formation of the mathematical apparatus that is able to simulate conditions of external effects. Testing effective methods for the concrete quality control developed by authors of this paper has been performed at the construction site. The conditions under study are characterized by a large number of ambiguous factors influencing the quantitative indicators of quality control criteria.

Abstract. This paper presents the physical phenomenon of concrete fracture process by static uniaxial compression. The analysis of strength characteristics of concrete is carried out using fracture mechanics technology, and what is more, the actual operating conditions of structures are evaluated. The expediency of using energy approach and kinetic theory is given to consider material fracture processes with a large number of defects.