The article highlights the issues related to the study of physical and mechanical characteristics of bulk materials, namely internal friction coefficients in static and dynamic modes. An innovative device of the carousel type for determining the frictional characteristics of bulk materials is described, which allows to implement the tasks of practical determination of dynamic coefficients of internal friction. Presented the program, methodology and results of research on the practical study of the internal friction coefficient of typical bulk products of agricultural production in the range of linear velocities of displacement of layers from 0 to 2.79 m/s, the reliability of which is not lower than 0.878.

This study presents a biomonitoring study of surface waters in the Krynka River basin, encompassing three major regional reservoirs: Khanzhenkovskoe, Olkhovskoe, and Zuyevskoe. These water bodies face significant anthropogenic pressure from mining effluents, industrial discharges, and domestic wastewater. Key pollutants identified are surfactants (SAAs), sulfates, phenols, chlorides, and manganese, with chemical oxygen demand (COD) exceeding regulatory limits. The research was conducted in September 2024. Based on the Specific Combinatorial Water Pollution Index, surface waters in the studied objects can be characterized as slightly polluted. To assess the negative impact of the identified pollutants on hydrobionts, the species composition of phytoplankton of the studied water bodies was analyzed. In the Olkhovskoe Reservoir and Olkhovaya River, cyanobacterial blooms (Oscillatoria agardhii G.) were observed, altering biodiversity in the Krynka River and Zuyevskoe Reservoir. Phytoplankton genera Synedra, Amphiprora, and Navicula—established bioindicators of aquatic ecosystem health—were dominant in Khanzhenkovskoe Reservoir, signaling nutrient enrichment and organic pollution. Changes in the species composition and structure of phytoplankton in the Krynka River, its tributaries and reservoirs, indicate a change in the level of saprobic water bodies from β to α-mesosaprobic, which indicates both the general level of surface water pollution and the accumulation of pollutants along the course of the river. The paper presents the results of fluorimetric analysis of photosynthetic activity of natural phytoplankton cells and demonstrates the possibility of using fluorescence induction curves for regular monitoring measurements. Fluorescence parameters indicate a general deterioration of photosynthetic activity of natural phytoplankton. The growth of Oscillatoria agardhii in the waters of the Olkhovskoe Reservoir and of green microalgae in the Zuevskoe Reservoir led to an increase in the fluorescence quantum yield (F_v/F_m) and the total photosynthetic activity index (PI), which makes it possible to use these parameters as indicator parameters reflecting the intensity of “blooming” of various phytoplankton species.

There are many devices for determining the coefficients of external friction, but there are almost no devices for determining the coefficients of internal friction of bulk products. The paper considers the question of physical and mechanical characteristics of bulk materials - the coefficients of external and internal friction. The purpose of this study was to create a device for determining the friction characteristics of bulk materials and its approbation by determining the coefficients of static and dynamic friction of grain materials. The basic parameters of the installation to determine the friction characteristics of bulk materials were defined - static and dynamic, internal and external friction coefficients. The developed installation allows measurements of shear forces inside the bulk material. The relationship between the coefficient of static and dynamic friction in organic and inorganic bulk materials is revealed. Grain crops have a higher value of the dynamic coefficient of friction at a speed up to 0.215 m/s. The difference between the values of static and dynamic friction coefficients was not revealed in the specified speed range of legumes. Dynamics of change in the coefficient of friction for grain crops depending on speed is studied using the example of wheat, and for mineral materials - using the example of table salt. For a speed range of 0-0.215 m/s, the relative change in the coefficient of friction for grain crops has a polynomial regression model, for mineral materials it has a logarithmic.

The article is devoted to the study of the coefficients of external friction of grain agricultural products-friction in static and dynamic modes, as the most important physical and mechanical characteristics of bulk materials. The description of carousel laboratory unit, program, methodology and results of studies on the practical determination of the coefficients of external friction for typical agricultural grain products according to the materials typical of the working bodies of the production machines. As a result of the research, it was found that in the range of linear velocities from 0 to 1.75 m/s, there is a change in the friction coefficients, which has a nonlinear character.

Introduction. The development of the agro-industrial complex until 2030 requires increasing the efficiency of the machine and tractor fleet with account for corrosion processes accelerating equipment wear. Existing assessment methods are based on empirical data and do not provide accurate forecasting. The introduction of AI and digital solutions will automate testing, reduce costs and improve the accuracy of assessing degradation caused by corrosion processes. Aim of the Study. The aim is to determine the compliance of experimental data on the effect of salt spray on the corrosion of agricultural machinery components with the distribution law through the example of reversing light switches. Materials and Methods. The object of study was reversing light switches widely used in agricultural machinery. The studies were carried out in a salt spray chamber with parame­ters corresponding to GOST R 52230 and GOST 9.302 for 200 hours with intermediate inspections every 48 hours. During the tests, the degree of corrosion was determined, calculated by the area of damaged sections. Using mathematical methods there was calculated the mean deviation, median, variance, standard deviation, skewness, kurtosis, and range of the sample. Results. As a result of the tests, the operability of the samples was confirmed and the obtained data compliance with the Weibull distribution law was assessed. It was experimentally established that the active phase of surface degradation of reversing light switches increases starting from 96 hours of exposure in the salt spray chamber that is caused by the destruction of protective coatings and progress of pitting corrosion. The use of a quadratic regression model made it possible to describe the dependence of corrosion damage on exposure time. Discussion and Conclusion. The statistical analysis of the sample confirmed Weibull distribution fit that makes it possible to predict further corrosion progress and improve performance assessment of products in salt spray conditions. Obtained parameters allow predicting the resource of components. The results of the study provide a basis for crea­ting digital twins and adaptive maintenance systems using artificial intelligence, which minimize machinery downtime.