In world practice, traditional blades used in high-speed wind turbines, both horizontal-axial and vertical-axial, have a wing-shaped profile. However, for horizontal-axial wind turbines, blades with such a profile have a fairly narrow range of operating values of the angle of attack of the incoming air flow and a low value of the moment of pulling from place. As for vertical-axial wind turbines, the self-starting of the rotor with wing blades is completely absent and additional devices are needed to start the rotor into operation. In order to ensure the selfstarting of the rotor and the operation of the wind turbine at high and low wind speeds, a new shape of the blade profile was developed, called non-closed wing profile. The concept of the development is that the blade should have a configuration in which the pulling force is involved at the beginning of the movement, and then, with the establishing of the movement, a lifting force would arise, which acquires a prevailing character in the operating mode. The article presents the results of experimental studies of the aerodynamic characteristics of the developed non-closed wing blades. One of the results obtained is to determine the effect of the thickness of the blade profile on the range of values of subcritical angles of attack of the incoming air flow and the differences between the nature and range of changes in the coefficients of lifting force and pulling force in a traditional wing blade and a blade with a non-closed wing profile. Studies of the rotor model of a vertical-axial wind turbine with non-closed wing blades have confirmed the presence of its self-starting and operability even at low wind speeds.
A significant disadvantage of parts made of linear block polyurethanes under conditions of friction contact in the presence of an aqueous medium is the intensification of hydrolysis processes and decrease in volume strength. It was proposed to slow down the hydrolysis of polyurethanes in three ways: by directed changes in chemical structure, by electromagnetic radiation of different intensities and by creation of composite materials, based on the principle of additional intermolecular crosslinking at the manufacturing and hot processing stages. The conditions for the formation of a smooth wear-resistant surface that protects the material from rapid destruction are revealed.
ZnO, ZnO/Alginate coatings were obtained on the pre-anodized Ti6Al4V substrates by the thermal substrate deposition method (TSD). In the frame of this work, the TSD method was at first applied for obtaining ZnO coating from aqueous alginate-containing and alginate-free solutions on a metal surface. XRD, SEM analyses show that the biopolymer has a significant influence on the formation of the coating, their morphology, texture, structure of ZnO nanoparticles. The average rate of ZnO deposition from alginate containing solution is 30 μm/min, while from alginate-free solutions – 6 μm/min. In the presence of alginate, spherical particles with flower-shaped inclusions are formed, while from the polymer-free solution, single crystals in the form of tetrahedral were obtained. Zone of inhibition test against Gram-positive S. aureus ATCC 25923 and Gram-negative E. coli ATCC 25922 proves the antibacterial activity of the ZnO/Alg coatings.
Results of scientific researches show the trend of active using nitrides and borides of transition metals and their combination in developing protective materials. While single elements nitrides have been well studied, their multilayer modifications and combinations require more detailed study. Physical-mechanical properties and structural-phase state of multilayer coating according to the deposition conditions is an important task for the study. It will be the analysis of physical-mechanical and electrical properties of coatings based on refractory metals nitrides, their structure and phase composition and surface morphology depending on the parameters of condensation. It was established the structure and behavior of nano scale coatings based on refractory metals nitrides (Ti, Zr) depending on the size of nano grains, texture, stress occurring in coatings.
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