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Development of a plasma-chemical method for producing amorphous silicon dioxide nanoparticles

https://doi.org/10.58224/2618-7183-2022-5-5-80-90
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 80-90 p.
Abstract
One of the most promising areas of production is additive technologies of building, in particular powder 3D printing. The aim of the work is to create a plasma-chemical method of obtaining amorphous silicon dioxide, satisfying the characteristics for the use of additive technologies of build-ing products, as well as in columns used in high performance liquid chromatography - one of the most common methods of study, as well as control of the environment and production products. One of the main requirements for particles is a porous structure with a surface that has a chemically bonded or physically coated active phase used for separation. Experimental installation for obtaining amorphous silica was developed, the feature of which was the possibility of rapid and continuous supply of pressed briquettes, rather than powdered material as it was previously. Studies have shown that the developed plasma-chemical process implemented in the condition of evaporation of briquettes consist-ing of 70% sand and 30% coke is effective enough to produce silicon oxide nanoparticles smaller than 200 nm. The developed method of obtaining nanoparticles should be further investigated on the ability to obtain nanoparticles smaller than 20 nm, it is so necessary to obtain the specific surface area of 200 m2/g, which will make it possible to produce from this raw material particles of the fixed phase carrier column of high-performance liquid chromatography.
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FLAT BENDING SHAPE STABILITY OF RECTANGULAR CROSS-SECTION WOODEN BEAMS WHEN FASTENING THE EDGE STRETCHED FROM THE BENDING MOMENT

https://doi.org/10.58224/2618-7183-2022-5-4-5-18
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 5-18 p.
Abstract
The article presents the solution to the problem of calculating the lateral buckling of wooden beams with a narrow rectangular section, taking into account intermediate point fixing in the edge stretched from the bending moment. The structure is considered as an orthotropic plate, the calculation is performed by the finite element method (FEM). To obtain a result that is valid for any beam geometry, the system of FEM equations is reduced to a dimensionless form. The dimensionless parameter that determines the value of the critical load is calculated based on the solution of the generalized eigenvalue problem. The numerical calculation algorithm is implemented in the MATLAB environment. The developed technique is verified by comparison with calculations in the LIRA and ANSYS software systems using flat and volumetric finite elements. A comparison is also made with the calculation formula presented in the Russian design standards for wooden structures SP 64.13330.2017 for the coefficient, taking into account intermediate fixing, with pure bending. It has been established that this dependence rather roughly takes into account the fastening from the bending plane of the edge stretched from the bending moment. Using the package Curve Fitting Toolbox of the MATLAB environment, we have selected refined formula for the coefficient, which can be used in engineering calculations.
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INVESTIGATION OF THE PROPERTIES OF ASPHALT CONCRETE ON MODIFIED BITUMEN POLYMERS

https://doi.org/10.58224/2618-7183-2022-5-4-19-29
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 19-29 p.
Abstract
The paper considers the method of obtaining bitumen modified with a Honeywell TitanTM7686 polymer additive and the preparation of asphalt concrete mixtures based on it. The aim of the work is to study the properties of the obtained bitumen and the possibility of its use in road organizations of the Vladimir region for the manufacture of asphalt concrete with improved deformative indicators. The study was carried out on bitumen BND 70/100 LLC LUKOIL – Nizhegorodnefteorgsintez, determined not only the main indicators of bitumen, but also some additional ones necessary to determine the intervals of mixing and compaction. A step-by-step algorithm for introducing an additive into bitumen is described, the optimal amount of the introduced modifier, temperature and mixing time are determined. The obtained test results of the modified bitumen were compared with the data of the initial samples. Next, the selection of the composition of the asphalt concrete mix was carried out and samples were made on modified bitumen and bitumen without a modifier. From the prepared asphalt concrete mixture A16Vn on bitumen modified by Honeywell Titan 7686, the top layer of the coating with a thickness of 4 cm was laid on the pilot site. After the installation of the asphalt concrete layer, cuttings were selected and studies of the selected samples from the coating were carried out. The test results showed a significant improvement in the main indicators of asphalt concrete mixtures and asphalt concrete, as well as resistance to rutting, which could not be achieved without the use of a modified binder.
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BINDER COMPOSITIONS BASED ON PORTLAND CEMENT AND VOLCANIC ASH

https://doi.org/10.58224/2618-7183-2022-5-4-30-38
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 30-38 p.
Abstract
Today, preference is given to composite binders. The use of dispersed mineral fillers makes it possible to realize the potential of binders to a large extent, which leads to an increase in the physico-mechanical, operational and technical properties of composite binders, as well as building materials based on them, and reduces the consumption of expensive binders. The creation of highly effective composite binders is based on the management of their production technology at all stages: the selection of raw materials, the development of optimal compositions, the use of mechanical activation of raw materials, the modification of composite binders with functional chemical additives, and some other methods. The use of volcanic ash in the world is quite diverse, it is used not only as additives for building materials, but also it has found its application in medicine. Many countries are beginning to use volcanic ash as a building material. The article presents the results of obtaining binder compositions of optimal composition based on Portland cement and volcanic ash. Experimental studies of the granulometric composition have been carried out, the results of tests of binder compositions of the compositions: cement – volcanic ash, prepared in a vibratory mill, have been presented. The results of physical and mechanical tests of binder compositions with different content of volcanic ash, activated for 10 and 20 minutes in a vibratory mill, have been obtained. Research work has been carried out to study the microstructure of volcanic ash.
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RESULTS OF ENDURANCE TESTING OF PREFABRICATED CRANE STRUCTURES

https://doi.org/10.58224/2618-7183-2022-5-4-39-49
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 39-49 p.
Abstract
The purpose of the work is to analyze the results of tests of prefabricated crane beams for endurance during cyclic tests on a specially designed stand. The method of carrying out such tests is given. It indicates the inadmissibility of the operation of steel crane structures with cracks and the importance of research aimed at increasing the endurance and durability of crane beams. It proves the need to develop new crane beams (various profiles) to increase the period of accident-free operation of industrial buildings (using bridge lifting mechanisms with heavy duty) up to 25 years. It is proved that the developed prefabricated crane beam has improved (in comparison with the standard) characteristics.
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POST-PANDEMIC URBANISM IS THE CURRENT REALITY

https://doi.org/10.58224/2618-7183-2022-5-4-50-60
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 50-60 p.
Abstract
The article discusses current problems and trends in the development of post-pandemic living spaces of the future. Growth of population affects the increase in demand for development of new areas. The 21st century is a period of innovative ideas, whereby society will rethink, improve and transform the environment to ensure high-quality living standards for the population. Architecture is characterized by continuity from the surrounding world. The main goal of the project is to reveal criteria of architectural space, which will allow mankind to live in a comfortable environment, even in a period of forced critical conditions. After studying the theoretical basis, there was a need for a comparative analysis of modern residential facilities and in determining general trends in construction. Analysis of volume-planning structure and architectural project of living spaces in recent years helped to formulate directions in the development of the post-pandemic city. The hypothesis was formed during the research, which suggests that the increase in the number of ideas about cities of the future contribute to safety and adaptability, harmonious visual appearance, the development of modern technologies. The thought movement is expanding, which is helping to build cities over the next 20 to 30 years. This work can become the basis for conceptualizing and systematizing the vision of post-pandemic urbanism.
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TYPOLOGY AND CLASSIFICATION OF ORTHODOX CHURCHES OF KAZAN BY PLANNING STRUCTURE

https://doi.org/10.58224/2618-7183-2022-5-4-61-70
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 61-70 p.
Abstract
The article is devoted to the compilation of a typology of a religious objects located on the territory of Kazan, built in the period from the XVI to the beginning of the XXI century. In order to identify development trends and determine the prevailing planning structures. Analysis of religious objects of Kazan allowed to trace a number of distinctive features of temples and calatog them according to functional typology. Classify all the objects according to their planning structure, the type of its development and the architectural planning solution. Ultimately, this article can become the basis for creating the aforementioned methodicak base for creating new model projects of religious architecture, based on the canon of the Orthododx church building, developed from the XVI to the XIX centuries.
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DESIGNING THE COMPOSITION OF ASPHALT CONCRETE BY THE CALCULATION METHOD

https://doi.org/10.58224/2618-7183-2022-5-3-5-16
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 5-16 p.
Abstract
The article proposes a promising technology for designing asphalt mixes based on the method of "irregular packing" of figures of different sizes and shapes. The calculation has been improved and adapted to deter-mine the bulk density of asphalt concrete depending on the content of bituminous binder. A detailed algorithm for designing asphalt mixes based on the "irregular packing" method is described. MS Excel spreadsheets have been created with calculation formulas for converting the grain composition of the mineral part of the asphalt concrete mixture, the content of bituminous binder by volume and recalculating the bulk density of asphalt concrete, the content of air voids, voids in the mineral aggregate and voids filled with bituminous binder. In order to justify the application of the "irregular packing" method of figures of different sizes and shapes in determining the bulk density of asphalt concrete, the results of the calculated data were compared with laboratory tests of control samples during the preparation of ShMA-16 and A 16Vn asphalt concrete mixes at the plant, as well as cores taken from the coating on highway. As a result of the comparison, it was found that the discrepancy between the obtained experimental and calculated values in terms of bulk density does not exceed 0.02 g/cm3, and in terms of the content of bituminous binder, less than 0.2%.
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TECHNOLOGICAL FEATURES OF THE CONSTRUCTION OF A DEMOUNTABLE FOUNDATION FOR TOWER STRUCTURES

https://doi.org/10.58224/2618-7183-2022-5-3-17-26
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 17-26 p.
Abstract
The paper proposes a new type of modular demountable reinforced concrete foundation for the construction of tower-type structures. Numerical modeling and design features of the manufacture and installation of the foundation, implemented under patent 2633604 “Demountable foundation for support” for a real tower with a height of 30 meters and a power of a 150 kV wind power plant, are given. The reduction of material consumption is achieved due to the formation of a cavity in each typical module and filling it with soil or any inert material. The result of the proposed solution is to increase the bearing capacity of the foundation as a whole, increase the strength and rigidity of its main joints, as well as simplify installation in comparison with traditional approaches to design. Moreover, the foundation modules, where maximum stresses occur, can be made of fibre concrete.
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SOLID CARBIDE TOOL WASTE RECYCLING TECHNOLOGY

https://doi.org/10.58224/2618-7183-2022-5-3-27-34
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 27-34 p.
Abstract
Carbide materials are widely used in various industries. However, due to the limited world reserves of tungsten and cobalt, as well as the accumulation of hard-to-process waste of solid carbide materials, the question arises about alternative sources of raw materials. So a large amount of waste is generated by the manufacturing industry. The main methods of processing require a significant consumption of reagents and energy, are distinguished by the toxicity and aggressiveness of working media, and a variety of special equipment. Electrochemical methods make it possible to significantly simplify the technological scheme and hardware design of the process, reduce the duration of recycling waste and improve environmental performance. The paper presents a technique for the disposal of carbide tools by the electrochemical method. Comparison of the compositions of electrolytes and current sources is carried out. Under comparable conditions, the highest current efficiency during oxidation of WC/Co alloys is achieved in nitric acid electrolytes. However, when using nitric and hydrochloric acids, harmful substances are released during electrolysis. Further experiments were carried out using sulfuric acid. The optimal reducing agent has been determined - hexamethylenetetramine. Powders of anode sludge were obtained, which were investigated by thermal analysis and energy dispersive methods. The chemical composition of the sludge has been established, which is defined as 20% oxide and 80% tungsten carbide.
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