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BENDING TEST OF A METAL-WOOD PANEL WITH FLAT GALVANIZED SHEET WALLS STIFFENED BY WOODEN RIBS
Authors: T.R. Barkaya, S.L. Subbotin, A.V. Gavrilenko, S.I. Kazimirov
Abstract: The features of modeling post-stressed structures erected using phased tension of monostrends are considered. It is indicated that the separation of the calculated compression force into stages is carried out to reduce the time of the formwork turnover and more fully utilize the mechanical properties of reinforcing ropes due to the early inclusion of concrete in the work and compensation for the stress losses of the first stage. The conclusion is made: as a result of the fact that both its own weight and mounting loads act on concrete that has not reached the design strength and deformability, the structure acquires initial deformations (deflection), which, after hardening, remain in it, therefore, at the stage of secondary compression (and even more so by the time of loading with an operational load) the element already has some geometric nonlinearity. It is noted that the question arises about taking this factor into account when drawing up design schemes of post-stressed structures and the influence of the initial stress state on the distribution of forces in the element.
Keywords: : reinforced concrete, monolithic concrete, post-stress, reinforcement without coupling, monostrend, geometric nonlinearity, concrete retention
EFFECT OF COMPLEX ADDITIVE ON CREEP OF FINE-GRAINED CARBONATE CONCRETE
Authors: V.V. Belov, T.R. Barkaya, P.V. Kulyaev
Abstract: Fine-grained carbonate concretes are a fairly popular material at present, with good indicators for crack resistance, frost resistance, criteria for durability and reliability of building materials and structures. The task of finding the most economically and ecologically justified ways to increase the deformation properties of this concrete is relevant. The article reflects the results of the investigation of deformations of fine-grained carbonate concrete with a complex additive consisting of finely dispersed limestone filler and superplasticizer. Deformations are divided into conditionally instantaneous, short-term and long-term (creep). The study uses a method of planning experiments and special equipment, electric strain gauges for measuring instantaneous deformations and hour-type indicators for measuring creep deformations. It is shown that complex additive contributes to reduction of deformations of fine-grained carbonate concrete and leads to increase of their durability due to modification of structure formation and intensification of hydration process.
Keywords: fine-grained carbonate concretes, deformation properties, creep, influence, chemical additives
A METHOD FOR QUICKLY DETERMINING THE WEIGHT HUMIDITY SAND FOR CORRECTING THE COMPOSITION OF CONCRETE
Authors: Yu.G. Kosivtsov, V.I. Gultyaev
Abstract: The article describes an express method for determining the weight moisture content of sand for the manufacture of concrete mix, which allows for 5–7 min without the use of complex computer technology and equipment to calculate the required amount of mixing water.
Keywords: concrete mix, weight humidity of sand, energy saving
FEATURES OF APPLICATION OF FREQUENTLY RIBBED PREFABRICATED-MONOLITHIC FLOORS IN MODERN HOUSE-BUILDING
Authors: A.V. Levikov
Abstract: The article discusses the main advantages and disadvantages of the technology of using precast-monolithic floors in modern housing construction in comparison with prefabricated hollow-core floor slabs and solid monolithic slabs. Particular attention is paid to the main problem of this type of floors – the extremely low distribution capacity of loads across the span. The result of the calculation of the distribution capacity of the load of various arrangements of ribs, armored belts, unfastening beams for a concentrated load is presented and analyzed. Recommendations are given on the expedient field of application of often-ribbed prefabricated monolithic ceilings in housing construction.
Keywords: often ribbed prefabricated monolithic ceilings, hollow blocks, stiffener
APPLICATION OF A COMPUTER ALGEBRA PACKAGE FOR SOLVING
OF TECHNICAL THERMODYNAMIC PROBLEMS
Authors: F.V. Kachanovsky
Abstract: Characteristic example of MathCad application for solving of technical thermodynamic problems is considered. MathCad methods are compared with traditional methods, which were created in the days of hand computations. Advantages of MathСad are demonstrated.
Keywords: MathCad, technical thermodynamic problem, clapeiron equation, formula, function, computer programme, graph
ALGORITHMIC MODELS OF ELECTRIC LOAD CONTROL IN POWER SUPPLY SYSTEMS
Authors: K.B. Korneev, Yu.M. Pavlova, R. Osei-Оvusu
Abstract: The necessity of power consumption forecasting is indicated, which requires a qualitative and quantitative analysis of existing load curves for different groups of power consumers. It is noted that the use of intelligent accounting systems allows you to accumulate a large amount of statistical data that require further processing. Due to the fact that visual methods for identifying and grouping data are costly and not always accurate, it is proposed to average the collected statistical data and identify typical profiles (patterns) in them, according to which subsequent measurements can be attributed to a separate group (cluster) within the entire sample of load profiles.
Keywords: power system, load profile, pattern, forecasting, electrical analyzer, cluster, analysis, control, tariff
THE MAIN PROVISIONS OF THE LAWS OF THERMAL RADIATION
OF GAS VOLUMES OF ELECTRIC ARCS AND TORCHES DISCOVERED
IN RUSSIA (IN TVSTU)
Authors: A.N. Makarov
Abstract: The description of the fundamental laws of physics discovered by the author, the laws of thermal radiation of ionized and non-ionized gas volumes is given. On the basis of open laws, a modern theory of heat transfer and methods for calculating heat transfer in electric arc and flare metallurgical furnaces, furnaces of steam boilers, and combustion chambers of gas turbine plants of power plants have been developed. The use of scientific discovery makes it possible to create innovative electric arc steel-making furnaces, flare heating furnaces, furnaces, combustion chambers in which the consumption of electricity and fuel is reduced, productivity and service life are increased, and the amount of harmful emissions into the environment is reduced.
Keywords: heat exchange, heat radiation, electric arc, torch, furnaces, furnaces, combustion chambers
IMPROVING THE ACCURACY OF POWER CONSUMPTION FORECAST
OF INDUSTRIAL ENTERPRISE WITH ITS OWN GENERATION
Authors: S.V. Marinova
Abstract: The traditional ways of saving electricity by industrial enterprises are indicated. The advantages of coherent gas piston installations are described. The technique for increasing the accuracy of the forecast of power consumption of an industrial enterprise with its own generation is considered.
Keywords: electricity forecasting, artificial neural networks, gas piston installation, simulation, load, power grid
ON THE CONCEPT OF N-SYMMETRY OF A SPATIAL BODY
Authors: Al.A. Shum, A.M. Vetoshkin, An.A. Shum
Abstract: In the article the general concept of n-symmetry is transferred to the case of space. The issues of n-symmetry of a spatial body are considered. The concept of the center of n-symmetry of the body is introduced.
Keywords: symmetry, c-symmetry, s-symmetry, n-symmetry, center of symmetry, center of n-symmetry, function of three variables, density function, body, mass, center of mass
INFLUENCE OF MgO HYDRATION DEGREE
ON PROPERTIES OF Zn-Mg HYDROGEN SULFIDE ABSORB
Authors: K.A. Veres, V.V. Usov, A.A. Ilyin, S.P. Kochetkov
Abstract: The physical and sorption characteristics of a hydrogen sulfide absorber based on zinc oxide have been studied. It is indicated that magnesium oxide of varying degrees of hydration was used as a promotional additive in the work. The results of a study using X-ray phase analysis of the MgO hydration process in water are presented. It was found that with an increase in the hydration time of the magnesium oxide additive from 10 to 40 min, the temperature of the maximum sulfur capacity of the sample increases by 100 °C.
Keywords: zinc absorber, magnesium oxide, sulfur capacity
RESULTS OF ORDINARY LENGTHENING OBSERVATIONS THE PRECIPITATION׳S ACIDITY IN TVER
Authors: F.V. Kachanovsky
Abstract: Analysis had made of dynamics of the precipitation acidity (atmospheric precipitation had fallen in Tver in 1990–2021 years). Time series models of the indicator pH and her evolution were examined. Qubic model have considered as adequate. Trend, cyclic component and seasonal indices of the indicator pH preserved his character in spite of time series lengthening.
Keywords: acidity, acid rain, precipitation, model, time series, trend, cyclic component, seasonal component, residuals, indicator pH
ESTIMATION THE LEVEL OF ACCUMULATION HEAVY METALS IN BOTTOM SEDIMENTS
Authors: G.N. Ivanov, I.V. Krivenko, M.A. Smirnova, S.R. Ispiryan
Abstract: It is noted that one of the most important indicators of an effective and reliable assessment of the ecological state of a water body is the content of heavy metals in its bottom sediments containing complete geochemical information about the evolution of a water body. The results of the analysis of samples of bottom sediments taken in the Upper Volga lakes and the Ivankovsky reservoir are presented. It is concluded that the composition of the deposits under consideration indicates the presence of various zones corresponding to the level of pollution and the peculiarities of the formation of the composition of these deposits. Three geographical zones on the territory of the Upper Volga are distinguished, characterized by a different (in terms of the content of heavy metals and toxic substances in bottom sediments) ecological state. It is emphasized that on the basis of verified information about the ecological state of the water body, its competent operation is possible.
Keywords: state of the water body, bottom sediments, heavy metals, pollution degree of water bodies