Hydroecological monitoring of the quality of river waters of the Amudarya river basin in the territory of Uzbekistan

The article considers the problems of irrigation water quality in Central Asia through hydroecological monitoring. Practical and scientific recommendations for solving these problems are offered. There are noted the necessity of development of scientific base of researches on all aspects of water quality and protection of water resources; adoption of laws and administrative documents on protection of waters and improvement of their quality; performance of various engineering, technological actions. The hydroecological state of surface waters of large irrigated areas of the Amudarya river basin was studied for regieon: Surkhandarya, Kashkadarya, Khorezm and irrigated zones of the Republic of Karakalpakstan. It is noted that the process of salinization of irrigated lands is dangerous for the region. According to the calculations 50...55 million tons of various salts are came to irrigated annually fields. This is the reason for the deterioration of the hydrological state of irrigated agriculture in the region.

Environmental aspects of impacts of the impurities in the industrial microsilica during its processing

The mechanism of inhibitory effects of microsilica impurities on microsilica dissolution was discovered. The relevance of the work is due to the demand for liquid glass in the enterprises of Central Russia and the lower cost of raw materials, namely sodium silicate, compared with analogues. Waste disposal helps to solve the problems of resource conservation and environmental management. Microslica was studied by differential thermal analysis using a TGA 2 in the temperature range of 20...800 °C with a heating rate of 20 °C/min in air. Modification of microsilica was carried out by mixing with sodium hydroxide with a concentration of 15...25 wt.% at a temperature 20...50 °C with stirring at 600 rpm. The mechanism of formation of by-products with the basis of the obtained data was determined. The greatest contribution to the inhibitory effect on the process of producing liquid glass is made by aluminum ions. The resulting byproduct, hydroalumination sodium is formed in several stages and is catalyzed by sodium silicate. The reduction in the rate of mass transfer and temperature in the modification process of the microsilica reduces the amount of produced byproducts. The mechanism of inhibition of the process of dissolution of microsilica, a byproduct of the production of aluminum fluoride, was determined. The mechanism of the formation byproducts was proposed. The activation energy of the polymerization reaction was obtained. The value of the activation energy is 7.73 kJ/mol, indicates that the synthesis process takes place in the diffuse region. The optimal parameters of physical and chemical modification are determined. Microilica is treated with sodium hydroxide with a concentration of 25 % at a temperature of 20 °C at a speed of 600 rpm.

The regression equations for random values of initial and final moisture content of foam-polymer-mineral insulation of main heat pipes

This article presents the conclusion of regression equations for random values of the initial and final moisture content of the material of foam-polymer insulation of steel pipes of main heat pipelines according to the results of tests conducted in the factory. The example of approximation of experimental data about the source and target moisture content of the samples of foam insulation pipes shows that the regression equations with the help of the considered algorithm is practically possible.

The phytogenic effect of different-aged black saxaul plants on the productivity of wormwood-ephemeral vegetation under the conditions of Karnabchul

The aim of the study is to determine the effect of different-age black saxaul plants on the productivity of wormwood-ephemeral vegetation through the study of the phytogenic field of this ephemeroid species. The phytogenic field of black saxaul has been studied by the phytomer method in the desert Karnabchul. The study showed that its influence in the minimum phytogenic field on the productivity of wormwood-ephemeral vegetation is negative, in the external part of the phytogenic field on bluegrass and forbs is positive, and on wormwood and sedge remains negative. The highest productivity indices are observed in them between the outer and inner and outer parts of the phytogenic field of the middle-aged generative plants of the edificator.

The influence of the bottom sediments on water quality of small rivers

The research is devoted to the study of the effect of bottom sediments on the water quality of the Akhangaran river. It has been established that below the wastewater discharge of the Almalyk Mining and Metallurgical Combine, bottom sediments are formed in the coastal areas of the Akhangaran River, in which significant concentrations of mineral and organic substances accumulated. The toxic metals, the concentrations of which exceed the normative levels, especially in the summer season were found in the water. A strong correlation (r > 0.5) has been established between the content of elements in bottom sediments and their concentration in the water of the Akhangaran river. The obtained data shows that bottom sediments are secondary sources of pollution of small rivers. Thus, the monitoring the water quality of small rivers in areas where non-ferrous metallurgy enterprises are located should be carried out taking into account the adverse effects of bottom sediments on the state of water bodies. The content of elements in bottom sediments varies widely on average from 0.01 (surface layers) to 32.1 mg/g (deep layers). It is characteristic that iron and copper in the bottom sediments are present in higher concentrations compared to other elements.