About the number
NON-AUTOCLAVE POROUS CONCRETE
BASED ON FUEL ASH
Authors: V.V. Belov, T.R. Barkaya, P.V. Kulyaev
Abstract: The work considers low-energy technology of non-autoclave porous concrete (NAPC) based on fuel ash. After closing with water and mixing in a conventional mixer, the feed mixture is poured into molds or formwork, where it swells and then solidifies under normal conditions or with little heat treatment. It is indicated that the use of NAPC with the same average density as conventional lightweight concrete on firing aggregates for reinforced load-bearing structures can be justified by close values of total porosity and associated elastic and deformative properties, as well as similar working conditions of reinforcement in these products. It is concluded that, in comparison with gas–reinforced concrete, NAPC favorably differ in greater stability of properties during manufacture, lower consumption of gas-forming additives, and in comparison with conventional light concrete – the absence of expensive large porous aggregates. Strength and deformation characteristics of NAPC are determined both at short-term and longterm active loads, which is the basis for further research on the use of this per-special material in bearing and enclosing structures.
Keywords: non-autoclave gas concrete, fuel ash as filler, low-energy technology, strength and deformation characteristics.
DRY MIX FOR RESTORATION AND RESTORATION OF BUILDINGS
BASED ON WHITE CEMENT AND HOLLOW GLASS MICROSPHERES
Authors: S.V. Perevozchikova, V.V. Belov
Abstract: The work reflects the urgency of the problem of restoration and restoration of architectural elements on the facades of buildings. Also reflected are the results of experimental work on the selection of the optimal composition of the mixture for lightweight architectural elements, which includes white cement, hollow glass microspheres, modifying additives and dolomite flour as a microfiller. The results of microscopic analysis of the material structure are presented.
Keywords: dry mortar, restoration, hollow glass microspheres, lightweight structures
ARCHITECTURAL AND LANDSCAPE ENVIRONMENT
OF HISTORICAL SETTLEMENTS: FROM SEMANTICS TO PRAGMATICS
Authors: V.V. Fedorov, M.V. Fedorov
Abstract: From the point of view of semiotics, the potential for the development of small historical cities in the central part of Russia is considered (on the example of the Tver region). The natural-climatic and socio-cultural features of the region are determined. A characteristic feature of small historical settlements is the presence of rivers and reservoirs. The role of water areas and coastal territories in creating a comfortable urban environment is analyzed. It is noted that the re-design of the contours of the coastline and the plastic treatment of adjacent areas opens up new opportunities for creating a multifunctional and comfortable environment. It is shown that the transformation of water areas and adjacent areas into structural elements of the future recreational framework ensures the unhindered movement of citizens and tourists along the shores; the organization of theatrical actions and concerts in the open air; the compositional diversity and the systematic nature of the visual series of sections of the coastline.
Keywords: small historical city, water area, coastline, reconstruction, coastal territories
SOLUTION OF THE PROBLEM OF STABILITY OF A CYLINDRICAL SHELL
MADE OF STEEL FOR PROPORTIONAL LOADING PROCESSES
IN A COMPUTER PROGRAM
Authors: S.V. Cheremnykh
Abstract: The theory of stability of shells beyond the elastic limit is considered. Marked: since, depending on the history of the loading process of an elastic-plastic system, its final deformation corresponding to the same external load is different, the study of inelastic stability problems should proceed fr om the analysis of simple combined loading processes leading to various critical deformations. Not only the question of the loading history, which leads to the minimum value of critical loads, is considered, but also the question of choosing and implementing such a loading history of this system, which gives it the maximum value of the stability lim it and load-bearing capacity. Innovative methods for solving the problem of stability under simple proportional loading for rectilinear trajectories in the direction of structural mechanics and mechanics of deformable solids, implemented in the developed computer program, are proposed.
Keywords: computer program, stability, bifurcation, shell, simple loading, trajectory, deformation, mechanics.
ANALYSIS OF THE ELECTRICAL CONDUCTIVITY
OF THE PRECIPITATION IN TVER DURING 2016–2020 YEARS
Authors: F.V. Kachanovsky
Abstract: Analysis had made of the precipitation′s electrical conductivity (atmospheric precipitation had fallen in Tver in 2016–2020 years). Time series models of the electrical conductivity were examined. Linear model has considered as adequate.
Keywords: сonductivity, acidity, acid rain, precipitation, model, time series, trend, cycle component, seasonal component, residuals.
RISK AND RELIABILITY MANAGEMENT IN POWER SUPPLY SYSTEMS
Authors: K.B. Korneev, Yu.M. Sokolova, R. Osei-Оvusu
Abstract: It is noted that the functioning of developing electric networks with distributed generation and demand management requires improving approaches to managing the reliability of the system. It is concluded that risk assessment and effective planning can be based only on a high-quality system analysis of the existing infrastructure, taking into account all factors. Some risks (primarily related to information security) that require a comprehensive study in order to prevent the occurrence of emergency situations are considered
Keywords: power system, risks, reliability, Internet of Things (IoT), security, management, distributed generation, demand management, alternative energy.
INFLUENCE OF ATMOSPHERIC SMOKING AND SLAG HEIGHT
ON HEAT EXCHANGE IN ARC STEEL MELTING FURNACES.
PART I. INFLUENCE OF ATMOSPHERIC HUMIDITY
ON LOSSES WITH GASES AND WATER
Authors: A.N. Makarov
Abstract: The composition of the dust and gas atmosphere affects the heat transfer in the arc steelmaking furnace. With a significant dustiness of the furnace atmosphere, the heat flux of arcs emitted by them into the free, not filled with charge, space is mainly absorbed by the dustgas medium and carried away from the furnace in the form of heat losses with exhaust gases. In the radiant atmosphere of the furnace, the heat flux of the arcs, radiated by them into the free space, reaches the walls, is absorbed by the water of the water-cooled panels and is carried away from the furnace in the form of heat losses with the cooling water.
Keywords: electric steel, electric arc, heat exchange, heat radiation, furnace.
MOMENTS OF A FLAT PLATE RELATIVE TO A STRAIGHT LINE
AND SOME QUESTIONS OF SYMMETRY
Authors: Al.An. Shum , A.M. Vetoshkin , An.Al. Shum
Abstract: The concept of n-th order moment of a flat plate relative to a given straight line is considered. A straight line is declared to be a line of n-symmetry if the moments of the n-th order of two sub-plates into which the original plate is divided by this straight line are the same. In this case, the lines of 0-symmetry turn out to be half-mass lines, and the lines of 1-symmetry – lines of equilibrium. The lemma proved earlier for half-mass lines and equilibrium lines can be carried over to the more general case of lines of n-symmetry.
Keywords: symmetry, c-symmetry, s-symmetry, center of symmetry, half-mass line, equilibrium line, density function, mass, center of mass, electric machine.
DETERMINATION OF THE ENERGY OF ACTIVATION
OF THE SYNTHESIS OF MAGNETIC LUBRICANT NANOOILS
BASED ON VISCOSIMETRIC STUDIES
Authors: A.N. Bolotov, O.O. Novikova, A.V. Novikov
Abstract: Equipment for experimental studies of the rheological behavior of magnetic nanofluids has been developed. It is indicated that the design of a rotational magnetic viscometer makes it possible to measure the standard characteristics of colloidal systems and to establish the structural features of liquids under shear stresses in a wide range of magnetic fields. A new method has been implemented to improve the antifriction and antiwear properties of magnetic nano-oils. It is proposed to estimate the activation energy of the chemical reaction of stabilization of colloidal systems using polymers based on the results of viscometric studies. The initial data for the calculation are experimental rheological curves taken at intermediate stages of the synthesis of polymer shells on dispersed particles in the process of obtaining magnetic nanofluids. The rate of the polymerization reaction was estimated as a function of temperature. It is noted that the results obtained will make it possible to obtain magnetic oils with specified rheological and tribotechnical properties.
Keywords: colloidal systems, magnetic nanofluid, magnetic lubricating nano-oils, viscometric studies, activation energy.
OF PLANT RAW MATERIALS MAY LILY OF THE VALLEY
Authors: M.G. Vinogradova
Abstract: The possibility of determining the chemical composition of the May lily of the valley by ultraviolet spectroscopy is discussed. The analysis of plant materials of populations of Lily of the valley in the composition of forest phytocenoses of torzhoksky district, Tver region. The phenolic compounds included in the studied plants were identified. The structure of the studied flavonoids is determined
Keywords: UV-spectroscopy, May lily of the valley, flavonoid compounds
REDUCED EXPOSURE TO POWDER COATING
Authors: V.V. Lebedev, N.G. Marilov
Abstract: It is noted that the powder method is increasingly used for painting metal products today. The advantages of this technology are described (the resulting paintwork is durable, durable and at the same time quite economical). It is separately indicated that using powder paint, it is possible to obtain various decorative environmentally friendly coatings. The general view of the technological line of preparation and application of powder polymer coating, the schematic diagram of spraying and deposition of charged particles on the parts are given. Various harmful and dangerous production factors affecting the employee during the organization and conduct of painting works are listed. The built prototype of the counter swirling flows apparatus is described, after testing which positive results were obtained and a decision was made to implement this device at TVZ LLC (Torzhok).
Keywords: powder painting, powder material, personal protective equipment, production factors.