Millet and problems of fodder production in Siberia

Available from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

INVESTIGATION OF MERCURY MIGRATION REGULARITIES IN SURFACE WATERS ON BASE OF FULL-SCALE OBSERVATIONS AND MODEL EXPERIMENTS

The mercury migration processes in the natural surface waters have been investigated. The aim is to develop the sensitive methods detecting the mercury in the natural waters, to determine the levels and changeability of the mercury content in the concrete natural objects, to determine the regularities of the mercury absorption with the clay minerals. The scales of the temporary mercury content changeability in the Katun river have been determined firstly. The new data about mercury content in the Baikal Lake have been obtained. The anomal dependence of the mercury sorption by montmorillonite upon pH medium has been found firstly. The methods for detection of the mercury in the natural waters with detection limit 1 ng/l have been developed. Application field: environment protection, monitoring of surface water qualityAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

The saturating mixture composition influence on the structure and properties of the diffusion chrome layer on gray cast iron

The article presents the results of research on the selection of the saturating mixture optimal composition during chromium plating of gray cast iron. It’s carried out the microstructural studies of the surface layer of gray cast iron SCh 12, obtained using saturating mixtures with different activators and their different percentages. Phase X-ray analysis showed that the obtained coatings on cast iron consist of chromium carbides Cr23C6 and Cr7C3. The carbide zone under the same conditions of diffusion saturation is formed at the amounts of activators exceeding 7%. It is shown that the coefficient of relative wear resistance of gray cast iron after diffusion chromium plating is directly dependent on the depth of the diffusion layer. The corrosion resistance of the coating with increasing thickness of the carbide zone also increases. At the same time, heat resistance decreases sharply with increasing percentage of activator. That is, the phase composition and morphology of the layer structure have a significant influence on the oxidation processes According to the method of experiment simplex-lattice planning, mathematical models of the dependences of the depth of the diffusion layer, corrosion resistance, oxidation, and the coefficient of relative wear resistance on the saturating mixture composition were obtained. Based on the obtained dependences, triple "property-composition" diagrams are constructed. The diagrams analysis confirmed the important role of activators in the process of diffusion chromium plating. It is shown that they promote the formation of active chromium atoms, which provides the formation of a continuous carbide coating. It has been established that during diffusion chromium plating of gray cast iron SCh 12 in order to increase the corrosion resistance of the diffusion layer in the saturating mixture, it is necessary to introduce NH4Cl and NH4F activators in an amount of 10…13%. It also provides with an increase in the coefficient of relative wear resistance of gray cast iron. The introduction into the saturating mixture of NH4Cl and NH4F activators, within 4…6% provides an increase in the scale resistance of the diffusion chromium layer by 10…15 times. The use of NaCl and NaF activators during diffusion chromium plating is impractical because when introduced into the mixture it saturates, in an amount of ≤ 13% they do not give a continuous carbide layer, significantly worsens its performance