No abstract

The article gives the reason for the formation of Lake Aydarkul, according to which Lake Aydarkul began to form, starting from the catastrophically high year of 1969 - as a result of the discharge of 21 cubic kilometers of Syrdarya waters from the Shardara reservoir. The area of the lake system reached 2000 km2, salinity of water – 2 – 4 g/l. In the next decade, there was a drop in the water level in the lakes and deterioration in its quality. By 1978, the depth decreased from 25 to 20 meters, and salinity increased to 7-8 g/l. An analysis of the available materials devoted to this problem showed that the water surface of Aydar and Tuzkan lakes extends from west to east for more than 180 kilometers, and the adjacent chain of Arnasay lakes stretches from north to south for more than 70 kilometers. The reason for the salinity of Aydarkul was indicated - before the commissioning of the Shardara reservoir, salt lakes were located on the site of the lakes, and only in the Tuzkan Basin fed by the Kly River was a shallow salt lake. The problem can be solved by transporting an additional volume of water to the lower reaches of the Amudarya, which will improve the ecological situation in the Aral Sea region, provide, over time, the formation of fresh lakes and create a water management system Syrdarya - Aydarkul - Zarafshan - dead lakes - Amudarya. This system can serve the broad development of fisheries, and also contribute to the opening of new agricultural areas of the republic, while creating several hundred new jobs. A method is recommended for solving an important national economic task of the industry. It is proposed that for the formation of the water system Syrdarya – Aydarkul - Zarafshan - “dead lakes” – Amudarya – Priaralye, it is necessary to design and build the main canal with several sections of a length of about 250 km, each of which communicates with the lake of the above system, will provide gravity communication of three large rivers of the Aral Sea basin. It is proposed to design the main canal with improved lining, which will provide high efficiency, which, in turn, will reduce the filtration coefficient and contribute to an increase in water intake for the needs of the national economy, expansion of irrigated areas and the development of fisheries in the region, and improvement of the ecological situation in the Aral Sea region.

The paper presents the results of a theoretical and experimental study of the wear intensity of the elements of the flow part of centrifugal and axial pumps. Theoretical formulas recommended by various authors, obtained for models with flat samples based on energy theory, do not consider the features of hydraulic machines. Considering the movement of a solid particle in the interblade channels of the impellers of centrifugal and axial pumps, we chose design schemes that correspond to hydraulic and physical wear processes. The analysis shows that the action of centrifugal and inertial forces in the interblade channel of the impellers of centrifugal and axial pumps results in the separation and redistribution of solid particles in the flow. As a result, in centrifugal pumps at the end of the blade and axial pumps at the end gap of the impeller, the local concentration of solid particles increases compared to the average. The paper also provides dependencies for calculating the intensity of hydroabrasive wear of pump working parts.

Currently, many authors have studied the uniform axisymmetric pressure head laminar and turbulent movement of water in hydraulic smooth and rough (with uniform roughness) pipes of circular cross-section. The results obtained in the study of a plane-parallel turbulent flow in pressure canals allows here only to outline the structure of the corresponding dependencies and to clarify the simplest case of unpressurized fluid movement, when this movement can also be reduced to plane-parallel or, in other words, to movement in a canal of infinitely large width with a flat bottom. In all other cases, the only way to solve the problem is an experiment. The construction of numerous free-flow watercourses and machine canals of pumping stations requires scientifically based calculation methods.

Today, in the construction field, high-strength textile materials are increasingly practiced with the external reinforcement of structural elements. For the manufacture of textile externally reinforcing materials, they are mainly used: fiberglass, basalt, carbon fiber, and other high-strength fibers and threads. In combination with an epoxy or polyester matrix, they form an unconventional building material - carbon fiber. Carbon fiber - in comparison with conventional building materials, it has a number of indisputable advantages, such as high tensile strength, low specific gravity, high ability to resist corrosion. Carbon fiber is currently listed as the most promising material used in construction. However, its use is often limited by high prices for reinforcing material, because of this, the use of such material in the designs of large structures is economically irrational. The conclusion is made that it is necessary to determine the best reinforcement method in which the least amount of material is spent without loss of quality.