Search

In this paper was studied the content of heavy metals in atmospheric dust of Dushanbe and Ayvaj. Dust samples were taken and analyzed to determine the content of heavy metals (HM): Zn, Pb, Cu, Cr, V, Ni, Co, As, Sr, MnO, TiO2 and Fe2O3 using X-ray fluorescence spectrometry. The pollution levels and environmental risks of HMs were assessed using the geoaccumulation index, contamination factor, pollution load index and potential ecological risk index. The results revealed severe contamination of atmospheric dust from Ayvaj and Dushanbe with particularly hazardous HMs such as As and Pb, the proportion of As is higher in the dust of Dushanbe, and the contribution of Pb is significant in the samples of Ayvaj. The concentrations of As, Pb, Zn, MnO, Sr, TiO2, V, Co in the dust of Dushanbe and As, Pb, Zn, Sr, TiO2, Cu in the dust of Ayvaj showed high variability (CV> 35%), which indicates an intense influence of anthropogenic activity. The results of the pollution factor analysis show that As, Co, V in Ayvaj atmospheric dust samples and Pb, Cr, Ni, V, MnO in Dushanbe samples were assigned to the class of very high pollution (CF>3). According to the results of the geoaccumulation index Ayvaj is heavily polluted with the following elements: V, Pb, Cr (3< Igeo ≤4). Based on the ecological risk index method, As and Pb were found to be priority pollutants in the study areas.

The agrochemical properties of soil are important for its fertility, plant growth and development, and harvesting. In this case, humus is one of the main indicators of the total amount of nutrients. These indicators vary by soil layer. The reduction of the amount of humus in the lower layers of the soil has a negative effect on the agrophysical and agrochemical properties of the soil. Soil humus is a complex of high molecular complex chemicals consisting of protein, amino acid, wax, tar, low molecular organic acids, cellulose, lignin, chitin and other substances. Its amount is closely related to a number of factors and conditions - the amount and quality of biomass falling into the soil, the chemical composition of the soil, the environment, water-air, thermal properties, and physical-mechanical properties. This article presents information on the chemical and agrochemical status of typical rainfed sierozems. According to the results of the study, rainfed sierozems are very low in humus, low to moderate in mineral nitrogen and mobile phosphorus, moderate to high in exchangeable potassium. Carbonates are not evenly distributed along the profile of rainfed silozems, that is, some sections differ from the surface layers in their carbonate content, while in other sections, some accumulation of carbonates is observed in the middle and lower layers.

This article presents the results of a numerical study of the stress concentration around two equal and unequal holes in an orthotropic spherical shell made of composite materials under the action of internal pressure. The influence of geometric (hole radii, shell thickness, distance between holes) characteristics, as well as material orthotropy and shear stiffness, on the stress state of spherical shells made of composite materials is studied. A numerical algorithm based on the finite element method has been developed and a software package has been implemented on a computer that allows solving the problem of stress concentration near two unequal holes in spherical shells made of composite materials.

In the process of energy reform, liberalization and deregulation of the electricity market, a number of features have been identified that are related to the fact that in the conditions of market relations, the economic benefit and the price of electricity for consumers become a priority. There is certain isolation of networks and power lines from generation facilities; attention is lost to such an important problem as the reliability and safety of power supply. In this situation, the load on the power elements of the electric network increases, there is a need to create appropriate reserves of generating capacities, to increase the throughput of electric networks. All this involves increasing the role of system operators and improving supervisory control systems. The strategic goal of this study was to analyze the development of the electric power complex by the creation of smart grid systems as a platform for market, managerial and technological innovations that provide a transition to a new level of development of the electric power industry in Uzbekistan.