URBAN CONSTRUCTION AND ARCHITECTURE
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Published By Samara State University Of Architecture And Civil Engineering

2542-0151

2021 ◽  
Vol 11 (2) ◽  
pp. 48-55
Author(s):  
Nikolay M. BOCHAROV

The study of the nature of high-temperature corrosion of metals is one of the tasks in substantiating the relevance of the use of corrosion-resistant, heat-resistant coatings and barrier layers obtained on the basis of the natural oxidation process. The article presents the gradation of oxidation of surfaces of 08kp thin-sheet steel at diff erent temperature-time parameters of one cycle “heating-cooling”. To regulate the processing modes and register thermal eff ects, a diff erential thermal analysis device was used. It is shown that the eff ect of elevated temperatures on steel in air at atmospheric pressure triggers an intensive growth of scale, which peels off from the metal base and breaks down. After descaling on the steel surface, in addition to blue tarnishing, in some cases, fi lms of a red tint were found. Based on the data of diff erential thermal analysis, an att empt was made to separate and interpret transformations related directly to steel and to reactions in scale associated with iron oxides.


2021 ◽  
Vol 11 (2) ◽  
pp. 62-66
Author(s):  
Sergey V. EVDOKIMOV ◽  
Alexey A. ROMANOV ◽  
Boris G. IVANOV

The experience of operation of surface emergency gates in ice-breaking conditions at a number of hydroelectric power plants has shown the insuffi cient eff ectiveness of the methods used to combat freezing of structures. The rules for technical operation of spillway dam gates in winter provide for heating of structures by slots, threshold and skin in conjunction with measures to maintain mines before construction. However, measures to heat gates and build mines are not always suffi ciently justifi ed and justifi ed. In order to obtain full-scale data and scientifi c information for the development of recommendations on operating and accounting modes during design, full-scale studies of stresses and defl ections in the load-bearing elements of the watershed gate of the hydroelectric power station were carried out. This article presents the results of fi eld studies in comparison with calculated values. As a result of the studies, information on the static operation of fl at gates in winter conditions is obtained, which is of theoretical and practical interest. The materials can be used to clarify technical operation rules and to clarify regulatory documents for the design of hydromechanical equipment at hydroelectric power stations.


2021 ◽  
Vol 11 (2) ◽  
pp. 162-170
Author(s):  
Aleksandr I. DANILUSHKIN ◽  
Vasiliy A. DANILUSHKIN

The article discusses the problem of increasing the effi ciency of the linear section of the main gas pipeline system by developing eff ective control algorithms for the operating modes of the gas cooling unit. To develop control algorithms for a gas cooling unit, adapted mathematical models of thermal processes in air-cooled gas devices and in a gas pipeline are used. It is shown that when considering the dynamic modes, the gas pipeline system can be represented as consisting of two dynamic links. The link “gas cooling unit”, which includes up to 24 electric drives with heat exchangers, is characterized by relatively short time constants. In the main gas pipeline, heat exchange processes proceed much more slowly. This circumstance allows the main att ention to be focused on the development of an eff ective control system for the cooling plant. The control is carried out by discrete or continuous change in the fl ow rate of the cooling air through the heat exchanger by adjusting the number of switched on air coolers and changing the fan speed. The search for control algorithms for air coolers is carried out by formulating and solving the problem of minimizing the root-mean-square deviation of the gas temperature at the outlet from the heat exchanger from the required value. To implement the obtained control algorithms, a functional diagram of the automatic control system for the operating modes of the gas cooling unit has been developed.


2021 ◽  
Vol 11 (2) ◽  
pp. 171-177
Author(s):  
Evgeny A. KRESTIN ◽  
Grigoriy V. SEREBRYAKOV

Non-contact seals with fl at slott ed gaps of drives of electric power systems used in switchgears of hydraulic units, as well as in pumps and hydraulic motors have been investigated. Calculation of seals based on average clearance results in an underestimation or overestimation of the leakage rate compared to the operational values. The regularity of the distribution of pressure and fl ow rate in the gap of a fl at conical slot is determined, and formulas for the fl ow rate (leakage) and friction forces acting on the walls of the conical slot are found. To solve the problem, the approximate Navier-Stokes and fl ow continuity equations are used. Several special cases of the fl ow of the working fl uid in diff erent gaps are considered: a plane-parallel gap with an oscillating wall and at a constant pressure gradient and a conical gap at diff erent ratios of the pressure drop and the frictional action of the moving channel wall. When the wall oscillates in a conical gap and constant pressure, the presence of an extremum is characteristic. In this case, an excess pressure appeared in the slott ed gap, creating a supporting force, and the pressure value became high enough. When the lower wall of the conical slot moves in the direction of the increasing gap, the pressure inside the slott ed channel, under certain conditions, can reach a complete vacuum, the value of which is limited by the bulk strength of the liquid and the pressure of saturated vapor at a given temperature. When the pressure drop and oscillations of the wall of the conical gap are additive, then at a suffi ciently high velocity of the wall movement, the pressure inside the slot can even increase and exceed the value of the supplied pressure.


2021 ◽  
Vol 11 (2) ◽  
pp. 139-154
Author(s):  
Mikhail V. DUTSEV

The article is devoted to the reality of the modern historical city in the totality of the actual values of the valuable heritage, traces of the past, mental codes, archetypal images and the memory of civilization. The place of history in today’s socio-cultural fi eld and in the professional context is not clearly defi ned. Together with the understanding of the need to preserve the heritage, traces and memory of the past, there are global trends that mediate the features of the glocal in architecture. However, even this compromise cannot fully demonstrate the complexity of the historical city viability. According to the author, it is necessary to search for reasons that sometimes appear outside the material reality, but address directly to the spiritual world and mental space of a person, which is the main purpose of the article. The emphasis is placed on the artistic dimension of environmental realities, which allows us to determine the living connections of history and modernity on the basis of the author’s concept of artc integration. The article is illustrated by some results of cooperation between the Nizhny Novgorod State University of Architecture and Civil Engineering and the Polytechnic University of Milan (Politecnico di Milano) in the fi eld of reconstruction and renovation of historically valuable territories and author’s photographs.


2021 ◽  
Vol 11 (1) ◽  
pp. 46-55
Author(s):  
Arman B. KOSTUGANOV ◽  
Vitaly V. DEMIDOCHKIN

This article discusses the issue of determining the value the average wall temperature of the plate of a recuperative heat exchanger type “air-to-air” with a corrugated mesh insert based on the results processing the data of a physical experiment to determine the thermohydraulic characteristics such heat exchange surfaces. It has been established that the temperature fi eld of heat exchange surfaces of this type is nonuniform, depends on the conditions of heat exchange and hydraulic regimes of air fl ow. Therefore, the adoption of the arithmetic means value of the measured surface temperatures as the calculated average temperature of the heat exchanger wall entails signifi cant errors in the subsequent processing of experimental data and fi nal the values of the heat transfer coeffi cients, the values the Nusselt criterion and the criterion equations of heat transfer. It is proposed to determine the average value the wall temperature of the heat exchanger based on the results of measurements the wall’s temperatures, the estimate of the coordinates the center of distribution the results of measurements the wall temperatures, the equations of heat balance and heat transfer.


2021 ◽  
Vol 11 (1) ◽  
pp. 160-168
Author(s):  
Viktor P. GENERALOV ◽  
Elena M. GENERALOVA

The study reveals the aspects that defi ne the concept of “lifestyle”, including the main categories: standard of living, lifestyle, quality of life and lifestyle. Insuffi cient knowledge of the mutual infl uence of people’s “lifestyle” on the typological structure of apartments and residential buildings, on the quality of the urban environment is emphasized. The infl uence of the level of urbanization of the city territory on the characteristics of the “urban lifestyle” is considered. Problematic issues are raised related to the debate on the relationship between building density and comfort and the quality index of the living environment. The main directions of fundamental research in the fi eld of architecture, aimed at the development of new types of buildings, are touched upon. The emphasis is made on the methods of using high-rise buildings for the humanization of the urban environment and the formation of a modern “compact city”.


2021 ◽  
Vol 11 (1) ◽  
pp. 169-174
Author(s):  
Elena V. SHLIENKOVA ◽  
Anastasia V. DOLGOVA

The article is devoted to the concept of an associative landscape and the phenomenon of the visual nature of its perception. The aim of the work is to study the sign-symbolic images of nature on the example of a cultural landscape and their visualization of graphic design. The article examines the features of associative landscapes, the semiotic concept of the cultural landscape and its semantic reading as a text, the concept of semiosphere and noosphere. The object of the research is the associative landscape as a special type of space perception based on a visual-semiotic language. The subject of the research is the cultural landscape as a visual-spatial category, expressed in sign-symbolic images and directly related to the natural environment.


2021 ◽  
Vol 11 (1) ◽  
pp. 143-159
Author(s):  
Vasily D. FILIPPOV

The article is devoted to the work of Irving John Gill during his heyday, and then in conditions when the principles of modernism discovered by him, due to the lack of society’s need for new architecture in the United States, were not needed in this country - from 1909 until his death in 1936. New technologies used by Gill in the construction of public and residential buildings from concrete are described as well as his unsuccessful participation in the Panama-California World Exhibition of 1915-191, the construction near Los Angeles of the “ideal” city of Torrance and end-of-life projects. The reasons why Gill did not become the leader of the American and one of the leaders of world architecture are discussed, and his work is still controversial.


2021 ◽  
Vol 11 (1) ◽  
pp. 56-62
Author(s):  
Sergej A. ANCIFEROV ◽  
Elena V. CHIRKOVA ◽  
Mariya N. KUCHERENKO

The reasons for the occurrence of an impact when closing a butt erfl y valve installed on pipelines that discharge sludge water from horizontal sedimentation tanks of treatment facilities are considered. The assumption about the possibility of water hammer was experimentally refuted. It is hypothesized that the cause of the impact is the disruption of the fl uid fl ow when fl owing around a fl at plate at critical angles of att ack. A numerical experiment was carried out, which consists in modeling the movement of a water fl ow in a completely fi lled, closed space of a pipe. As a result of the experiment, it was revealed that the fl ow stall was caused by the formation of zones of high and low pressure, respectively, before and after the valve. This provides additional energy to increase the closing torque, comparable to the force of a pneumatic actuator, and results in an impact.


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