STUDY OF THE INFLUENCE OF TECHNOLOGICAL PARAMETERS ON THE GRANULOMETRIC CHARACTERISTICS OF SUBMICRON ALUMINUM OXIDE IN α-FORM

Experimental studies of the influence of technological parameters of grinding alumina raw materials in a ball mill on the kinetics of the grinding process and the granulometric characteristics of activated alumina in the α-form have been carried out. It is found that the use of spherical grinding bodies leads to the formation of a specific four-modal granulometric composition with maxima: 0.5; 4.0; 50.0 and 400.0 microns, respectively. The disadvantage of using spherical grinding bodies is the uneven distribution of the introduced intensifier additive (PEG), which in turn causes adhesion of fine particles and the appearance of aggregates. This is especially pronounced at n = 100 rpm. When using grinding bodies of cylindrical shape, on the contrary, there is a tendency towards a bimodal nature of the distribution of particles with maxima in the regions of 0.4 and 4 μm, respectively, regardless of the rotation speed of the drum (n). The use of cylpebs does not provoke agglomeration of the fine particle fraction, which is observed in the case of spherical grinding bodies. When analyzing the kinetics of grinding alumina raw materials, two main stages of the process are identified. The first stage corresponds to the active fragmentation of large initial aggregates into constituent crystallites by the cleavage mechanism. The second stage corresponds to a change in the grinding mechanism from crushing to abrasion. It is found that carrying out the grinding process for 10 hours using cylindrical grinding bodies at n = 100 rpm and φ = 0.35 provides a high yield of the submicron fraction of the target product (1 μm) - up to 20 wt. %.

DETERMINATION OF DESIGN PARAMETERS OF A STEP DISK MILL

The calculation of the design parameters of a disc mill equipped with a feeder made in the form of a conical hopper is given. For shredders of the disintegrator type, it is very important to ensure the uniformity of loading of the crushed material of the working zone of active impact on particles. In addition, the most important factor is the throughput capacity of all sections of the grinding plant. The throughput should be determined by the design and technological parameters of the working chamber of the mill. Its overload can lead to a blockage of the working chamber, and insufficient throughput will negatively affect the intensity and effectiveness of the impact on the particles of the material. For example, insufficient concentration of particles in the secondary zone of the grinding chamber leads to a decrease in the efficiency of mutual abrasion. The article attempts to determine the design and technological parameters in the loading and accelerating parts of the disk mill. At the same time, it is necessary to coordinate the throughput of the disk spreader and the volumetric flow rate of the material particles flowing from the hopper. In this case, it is advisable to take into account that as a result of a rather high rotational speed and the size of the initial particles, with the wrong height of the radial blade of the spreader, material particles can roll over the radial blades, which leads to a delay of the material in the zone of the spreading disc. Therefore, it is necessary to determine the calculation formulas for finding the required height of the radial blade of the spreading disc, depending on the size of the initial particles. The formula demonstrates that the height of the separating blade depends on the particle size, the speed of rotation of the disks and the distance to the point of meeting of the particle with the radial blade.

FORMATION OF RECREATIONAL AREAS BY USING DISTURBED URBAN LANDS

The article is devoted to the problems of disturbed lands that are part of urban territories, the need for reclamation and the creation of recreational spaces based on them. There are a large number of quarries on the territory of the Belgorod region, many of which are no longer functioning and they need to be transformed. The work in this direction entails an improvement in the environmental situation, increases the quality of the urban environment and makes these objects attractive for investment. The authors consider the main factors affecting the reclamation of the territory, analyze the types of soil and identify the relationship of geodesy with the architectural component of reclamation, present foreign and domestic experience in solving problems related to disturbed lands, comply a table of the main quarries of the Belgorod region in order to identify features characteristic of this region. As a result of the research, proposals and methods are put forward, taking into account regional peculiarities, for the reclamation of a chalk quarry in order to create a recreational space and then integrate it into the forest park framework in Belgorod, which will lead to an improvement in the environmental situation and aesthetic perception of the city as a whole.

SELECTION AND ANALYSIS OF RAW MATERIALS FOR A PROTECTIVE AND DECORATIVE LAYER OF COMPOSITE MATERIAL

With modern housing construction, the cost of finishing work has increased significantly. The development of protective and decorative coatings is necessary, with architectural and artistic advantages and high performance properties with a slight increase in cost. It is necessary to develop a high-quality multilayer monolithic composite with a high degree of adhesion of functional layers to each other. Glass industry waste of various fractions and coloring salts of metals are proposed to be used for a decorative layer, which allows to obtain an almost unlimited color gamut of the coating during plasma chemical modification. The choice of application of high-alumina refractory and alumina cement in the protective layer is justified due to their high thermal resistance to sudden temperature changes. Compositions of a protective layer based on binders and a decorative layer using crushed colored container glass and coloring metal salts moistened with a 5% aqueous solution of liquid glass have been proposed, which makes it possible to significantly expand the raw material base for obtaining functional coatings on concrete. The melt heating temperature and the kinetics of its cooling are determined in order to identify rational rates and duration of high-temperature treatment for further coating creation. Rational rates of plasma processing of composite material for the formation of coatings of various textures are revealed

THE USE OF PHOTOCATALYTIC CONCRETES IN ROAD CONSTRUCTION

The article discusses the possibility of reducing the atmospheric environmental load of highways by applying compositions with photocatalytic properties to acoustic screens. It is found that the amount of nitrogen oxides on the territory of the city of Moscow exceeds the MPC norms. Therefore, a potential way to reduce the level of the average daily and maximum one-time MPC of nitrogen oxides is proposed, when using coatings of traditional acoustic screens with photocatalytic compositions. Titanium dioxide in anatase form is considered as a photocatalytic agent. To reduce the density and increase the porosity of cement compositions, a cellulosic suspension obtained by saturation in an aqueous medium with subsequent homogenization is introduced. The effect of cellulose in the considered cement systems in combination with a photocatalytic agent has been investigated. By the method of mathematical planning, a two-factor compositional experiment is compiled. In result, the degrees of influence of titanium dioxide and cellulose additives on the strength, density and water absorption of the composites under study are established. The study of the structure of the obtained composites shows that TiO2 is mainly located on the surface of cellulose fibers, which theoretically increases the useful surface for photocatalytic reactions and, as a consequence, the final efficiency of the compositions.

SELECTION OF A RATIONAL RECIPE OF LIGHTWEIGHT CONCRETE ON A MIXTURE OF CERAMSITE GRAVEL, NATURAL CRUSHED STONE AND GRANULAR SLAG

In conditions of dense urban development and a variety of engineering and geological conditions, the use of concretes with a combined aggregate of a rationally selected composition will solve the existing problem of reducing the mass of reinforced concrete structures of buildings and structures and maintaining the required strength and deformability. In this paper, studies have been carried out on the choice of a rational formulation of lightweight concrete based on expanded clay gravel, natural crushed stone and granulated blast furnace slag by varying the volume content of porous coarse aggregate and the volume content of fine aggregate in relation to the mixture. In total, 9 series of prototypes and 1 series of control samples are manufactured and tested. One series of samples includes three cubes with dimensions of 10x10x10 cm. All samples are tested in terms of density and compressive strength, the coefficient of constructive quality is determined. The results of the study shows that the introduction of expanded clay gravel into the composition of heavy concrete instead of part of the dense coarse aggregate and the replacement of the fine dense aggregate with granular blast furnace slag leads to an increase in the structural quality factor, that is, a decrease in the compressive strength of concrete is compensated for by an even more significant decrease in the density of the material, and means weight reduction. The increase in the coefficient of constructive quality of concrete based on expanded clay gravel, natural crushed stone and granulated blast-furnace slag in comparison with the control composition is 15.6 %.

DOMESTIC AND FOREIGN TYPES OF REDEVELOPMENT OBJECTS FOR HOUSING

Manufacturing has historically been the driving force behind economic growth and structural change. During the financial and economic crisis, governments in Europe provided short-term assistance to industries that had fallen into disrepair by converting them into market-oriented industries (such as steelmakers and car manufacturers). As cities grow and the density of megacities increases, the need for their "renewal" began to appear, which is characterized by the transformation of non-functional buildings and old abandoned buildings for the purpose of further operation. The state and private organizations were interested in the transformation of such territories and actively invest in these projects. Industrial complexes are transformed into areas with residential apartment buildings and offices, their own social infrastructure, transport, entertainment reflecting the needs of modern society. In the future, urban areas can benefit greatly from new opportunities. All over the world, industrial territories are an integral part of cities. The article discusses the experience of reconstruction of industrial zones in Russia and abroad. The industrial heritage is adapting to the new context of the city, using the principles of sustainability, economy and aesthetics

DETERMINATION OF DESIGN PARAMETERS OF A STEP DISK MILL

The calculation of the design parameters of a disc mill equipped with a feeder made in the form of a conical hopper is given. For shredders of the disintegrator type, it is very important to ensure the uniformity of loading of the crushed material of the working zone of active impact on particles. In addition, the most important factor is the throughput capacity of all sections of the grinding plant. The throughput should be determined by the design and technological parameters of the working chamber of the mill. Its overload can lead to a blockage of the working chamber, and insufficient throughput will negatively affect the intensity and effectiveness of the impact on the particles of the material. For example, insufficient concentration of particles in the secondary zone of the grinding chamber leads to a decrease in the efficiency of mutual abrasion. The article attempts to determine the design and technological parameters in the loading and accelerating parts of the disk mill. At the same time, it is necessary to coordinate the throughput of the disk spreader and the volumetric flow rate of the material particles flowing from the hopper. In this case, it is advisable to take into account that as a result of a rather high rotational speed and the size of the initial particles, with the wrong height of the radial blade of the spreader, material particles can roll over the radial blades, which leads to a delay of the material in the zone of the spreading disc. Therefore, it is necessary to determine the calculation formulas for finding the required height of the radial blade of the spreading disc, depending on the size of the initial particles. The formula demonstrates that the height of the separating blade depends on the particle size, the speed of rotation of the disks and the distance to the point of meeting of the particle with the radial blade.

RESEARCH OF THE FUNCTIONING SYSTEM OF THE LIGHTING MODE

The article presents the results of a study carried out within the framework of a systematic approach using the "Wu Xing pentagram" symbolic method. The object of the research is the category of "lighting mode". The indicated category as a certain system are used. A diagram showing the life cycle of the "lighting mode" category is proposed. Five main components of the system have been identified based on the sequence of the formation of needs in the creation of a lighting regime in the room: investment, quantitative characteristics, quality characteristics, energy characteristics, maintenance and operating features. The characteristics of lighting installations and space-planning solutions in the main premises of preschool educational organizations are analyzed. The priority components for these premises are energy characteristics. Compliance with quantitative indicators depends on the efficiency of maintenance. The needs of aesthetic and emotional satisfaction are secondary, significant costs are not provided. Thus, it can be judged that in the premises presented, the development of the category of "lighting mode" follows the path of pathological restrictions As a result, a conclusion is made about the mechanism of functioning of the "lighting mode" category in accordance with the relations arising between its elements, namely, the relations of support or restriction. The research results can be used in the future when examining the quality of the light environment and monitoring the lighting conditions in the premises.

IDENTIFICATION AND CLASSIFICATION OF URBAN PLANNING CONFLICTS IN THE USE OF WATER RESOURCES IN BELGOROD

Sustainable development of the territory is impossible without balanced processes of anthropogenic human activity and rational use of natural resources. The problem of sufficiency and quality of water resources is relevant for the city of Belgorod. For 2021, the Belgorod region is limited by the resources of local surface and underground wastewater, with a fairly high level of municipal, agricultural and industrial consumers. The relevance of this work also lies in the increase in anthropogenic load on the natural framework, which entails a significant deterioration in the quality of surface and groundwater. In this regard, urban planning conflicts arise, which have an impact on the development of the city territory and the quality of the living environment. The research examines urban planning conflicts in the use of water resources in Belgorod. The causes of urban planning conflicts in relation to riverine territories and available water resources have been identified. The identified regulatory, property, land use, transport, social and functional urban planning conflicts are classified according to the hierarchical level, by duration, by the method of occurrence, by type of location, by the nature of manifestation. The introduction of water-saving design into the urban planning practice of the city of Belgorod is justified.