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A review of most popular direct and indirect methods of skin friction measurement and their brief characteristic are given. A comparative analysis of measurement results is presented; the results were obtained using some of the methods in an incompressible turbulent boundary layer on a flat plate under conditions of the formation of a negative (favorable) streamwise pressure gradient on the plate surface and in a gradient-free flow. The degree of effectiveness of the methods under the conditions described is evaluated, and the limits of their applicability and limitations are shown.

Composition and properties of the main products of slow heating carbonization (1

Changes in the chemical composition of aspen wood after grinding in the ball, planetary, and vibrational centrifugal mills are estimated from the copper number, contents of water-soluble substances, monosaccharides in water-soluble substances, and the amount of easily hydrolyzed polysaccharides. It is stated that the destruction of polios and lignin occurs more intensively during the grinding of wood in the presence of sodium hydroxide.

The features of the processes of thermal decomposition of mechanoactivated technical fluorocarbon materials (FCM-MA) of substoichiometric and superstoichiometric composition in vacuum and inert media have been studied at 250

Composition of 133 urinary calculi from patients of the Novosibirsk Region was studied for the purpose of analysis of peculiarities of urolithiasis in this region. The studies were carried out by means of X-ray diffractometry and IR spectroscopy. It is demonstrated that more than 80 % of all the stones were oxalate-containing, and more than a half of them were of oxalate-apatite nature. Such a composition witnesses to the leading role of metabolic disturbances in the genesis of urinary stones. Struvite-apatite and pure carbonate-apatite concrements typical of infectious processes made up only 9.8 % of all the pathological formations. Uric acid was identified in 11.3 % of stones, 3 % of them being pure uric acid concrements. The obtained results are compared with the data of similar studies carried out in Moscow and Berlin.

The possibility of creating a multielemental standard sample of deep water of Lake Baikal is substantiated. This is a new type of standard sample of natural waters balanced with respect to a wide range of macro- and trace elements. A standard sample reflects the specificity of matrix composition of hydro-carbonate-calcium waters to which waters of many world rivers and lakes and rain waters belong. Creation of a standard sample of Baikal

Results of field observations of the formation and distribution of the chemical sink of mineral substances and heavy metals in the closed drainage of the Ob'

Various conditions of extraction of chemical elements (Cd, Zn, Cu, Cr, Mn, Pb, Ni, As, Hg) standardized in the composition of sediments of waste waters of urban purification works for their subsequent assay by the method of atomic absorption recommended for production control and estimation of sediments hazard class have been studied.  It is demonstrated that the maximal extraction of Cd, Zn, Cu, Cr, Mn, Pb and Ni is achieved when using a mixture of nitric acid and hydrogen peroxide for heating. A special preparation of samples is recommended for extraction of Hg and As. Taking into account the results obtained with the help of the method proposed, the hazard class of real waste water sediments of urban purification works of Kazan and Naberezhnye Chelny has been calculated, and the possibility of their use as fertilizer has been estimated.

Indirect oxidation of maleic acid by hydrogen peroxide electrochemically generated in situ from oxygen in the gas-diffusion electrode in 1 M Na₂SO₄ has been studied. The oxidation of substrate in divided cell with cation-exchange membrane is shown to proceed to malic acid, and in undivided cell destructive oxidation occurs to CO₂ and H₂O.

The composition of minerals, the structure of apatite and the content of ecologically controlled elements in the phosphorites from the Khubsugul (KhPB) and Dzabkhan (DPB) phosphorite-bearing basins of Mongolia are investigated. The structural chemical and mineralogical classification of the phosphorites is performed. With respect to the mineralogical composition, the major part of phosphorites belongs to the cherty and carbonate-siliceous types. The phosphate substance of the KhPB and DPB deposits is represented by hydroxylcarbonatefluoroapatite. As regards the ratio of the major components, the apatites comprising these phosphorites belong to the first subgroup of the alkaline type, i. e. are phosphorus-deficient with respect to the stoichiometric composition. The content of trace elements in phosphorites was estimated using the dimensionless universal characteristics, i. e. ecological index of phosphates, which was 1.186 for the phosphorites of the Khubsugul deposit and 1.643 for the Burenkhan deposit, which means their ecological safety and suitability for use as fertilizers without chemical processing and enrichment. The proposed classification and ecological evaluation are necessary for solving the problem concerning the choice of an optimal technology of phosphorite processing, including mechanochemical treatment as the simplest and ecologically safest one. The classification can be useful for solving the genetic problems and for the search for new phosphorite deposits.