Wave processes in column rods of a rocker machine

The propagation of stress waves in a column of rods of a rocker machine during a lift is considered at an arbitrary time instant. Using an integral transformation of time, the second-degree differential equation for displacement is solved where the force of the column dead weight is taken into account. It is shown that the stress variation is of a pulsating type; parameters and a form of the pulsation cycle are given. The fatigue strength of a thread in the union joint of rods and the lifetime of rods having an initial fracture are determined.     

Features of electroplating of nanocrystalline chromium coatings from electrolytes based on Cr(III)

It is shown that, for the development of new chrome-plating technologies, it is necessary to proceed from the complicated Cr(III) chemistry. The analysis of the complexation processes of Cr(III) with hydroxycarboxylic acids in aqueous solutions is given. The results of investigations of deposition processes of chromium coatings from sulfate, oxalate–sulfate, and formate–glycine electrolytes are presented. Thin chromium films, as well as chromium films alloyed with cobalt, are obtained from formate–glycine electrolyte. With the use of atomic-force microscopy, it is shown that the formed chromium films are bright and possess a nanocrystalline structure and codeposition of chromium and cobalt leads to the formation of a more uniform structure.     

Tribological characteristics of hip joint endoprostheses

We have studied the friction pairs for a head–insert kinematic node of human hip endoprostheses and rabbit hip endoprostheses, both normal (intact) and with an osteoarthritis model, in conditions of dry friction and lubrication with biological medium. We have discovered that the rabbit hip with an osteoarthritis model exhibits deterioration of tribological characteristics. From the tribological point of view, the most suitable friction pairs for human hip endoprostheses are zirconium ceramics–aluminum ceramics, Oxinium–aluminum ceramics, aluminum ceramics–aluminum ceramics, and aluminum ceramics–polyethylene, which have shown the smallest coefficient of friction, the lowest adhesion bond strength when sheared, and minimal dependence of these parameters on the value of external load.     

Molecular structures of the open-shell IPR isomers of fullerene C90

Fifteen open-shell isomers off the forty six IPR isomers of fullerene C₉₀ were found and investigated: 5 (C_s), 7 (C₁), 9 (C₁), 10 (C_s), 11 (C₁), 20 (C₁), 21 (C₁), 22 (C₁), 23 (C₂), 24 (C₁), 25 (C_2v), 41 (C₂), 42 (C₂), 43 (C₂), and 44 (C₂). According to developed by us approach the positions of single, double, and delocalized π-bonds in the molecules of these isomers are shown for the first time. The obtained results of electronic and geometrical structures are fully supported by DFT method with the B3LYP functional at the 6-31G and 6-31G* levels. Molecules of these open-shell isomers contain different radical substructures (mainly the phenalenyl-radical substructures), they should be unstable and could not be obtained as empty molecules. Nevertheless, there is a possibility of obtaining them in polymeric forms or as endohedral or exohedral derivatives.     

Investigation of distributed power generation based on renewable energy sources and hydrogen batteries

The paper deals with investigation of distributed renewable power sources use efficiency by the example of solar power plant, wind farm and biogas power plants. The paper uses statistical data collection on weather conditions and solar radiation in different regions of the Russian Federation to assess effectiveness. It has been found out that arrangement of solar power plants and wind farms in the Republic of Bashkortostan is more profitable than their arrangement in other regions (Astrakhan, Vladivostok, Gorno-Altaisk, Makhachkala, St. Petersburg), and the use of biogas power plant is profitable in the region, where the production of biofuels is possible, including the Republic of Bashkortostan. Moreover, the paper presents a high-speed magnetoelectric generator for microturbines. In order to save and generate electric energy in accordance with consumer load curve, hydrogen batteries have been examined.