bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of non-equidistant gray model based on optimization of background value in settlement prediction
Authors: Wei Jiameng , Jiang Huagen , Diao Jianpeng
Published: January 2021

In order to solve the influence of different original data series on model adaptability and fitting accuracy in non-equidistant grey model. Because the background value in the gray model is a key factor affecting the accuracy and adaptability of the model. Faced with this situation, this article uses the Newton-Cotes quadrature formula to optimize the background value, which improves the adaptability and fitting accuracy of the non-equidistant gray model. By constructing the model, the Newton-Cotes quadrature formula is applied to the application of the non-equidistant GM (1,1) modeling method in the settlement and deformation of buildings. The analysis shows that the new model method prediction is more suitable for building settlement monitoring and analysis, and the degree of fit is improved by about 30%. The new model is better than the traditional model.
Research on Deformation Control Measures of Surrounding Rock in Soft Rock Tunnel
Authors: Hao Junsuo
Published: January 2021

In order to study the control measures of soft rock tunnel surrounding rock deformation, based on the restraint effect of shotcrete anchor support on it, a support model was constructed, and numerical simulation was used to compare and analyze the restraint effects of different bolts controlling the surrounding rock deformation. The results show that: With the reduction of the bolt spacing (d), the resin bolt has a significant supporting effect compared with the mortar bolt support, the maximum displacement of the surrounding rock is reduced by 70.69%, and the maximum stress is reduced by 58.81%. With the increase of bolt length (L), compared with mortar bolt support, resin bolt has a more obvious restraint on surrounding rock deformation. The maximum displacement of surrounding rock is reduced by 57.89% and the maximum stress is reduced by 40.23%. When 4.5m <L< 6.m, 0.6m< d< 0.7m, the resin bolt has a significant effect on controlling the deformation of surrounding rock. In other cases, the use of mortar bolts or resin bolts to support the surrounding rock deformation has little significant difference.
Experimental Study on Thermal Expansion Property of Epoxy Mortar in Hydraulic Structure Repairing
Authors: Sun Yufei , He Jingjing , Ma Lingyun , Di Shengjie , Zhang Ying , Liu Jing , Xing Ruijiao
Published: January 2021

The thermal expansion property of epoxy mortar has a significant effect on the repair effect. Experiments were carried out to study the thermal expansion coefficient of epoxy mortar by changing the type of curing agent, various sand binder ratios and sand etc. The results show that the curing agent has a remarkable effect on the thermal expansion coefficient of epoxy mortar. When the type and content of curing agent are fixed, the influence of sand binder ratio and sand type on thermal expansion coefficient of epoxy mortar is relatively small. It is an effective way to reduce the thermal expansion coefficient of epoxy mortar with excellent curing agent. The research conclusion can provide a reliable basis for hydraulic concrete repairing.
Determination of properties of cermet coatings obtained by additive laser technologies
Authors: Biryukov V P
Published: January 2021

The paper presents the results of metallographic and tribological studies of 40Kh steel and multi component coating (Ni-Cr-B-Si, Co-Cr-W-Ni-B-Si) with the addition of 5 and 10 vol.% nano-tungsten carbide powder to the charge. The regularities of changes in the friction coefficients from pressure, sliding speed, jamming load from sliding speed and wear intensity of steel and surfaced coatings are shown.
An optimal experiment planning in the problem of longevity evaluation at crack propagation stage
Authors: Gadolina I V , Romanov A N , Bautin A A , Papic L
Published: January 2021

A large number of factors influencing the fatigue crack rate are traditionally studied separately. In this case, their interactions are not taken into account, and the experiment does not possess the property of optimality. The article describes the authors’ vision of the problem, how it would be possible to approach the solution of the research problem from the point of view of the theory of optimal experiment planning. Initially, it is proposed to consider three basic factors, namely: the influence of loading asymmetry, loading frequency and sequence of overloads. A full factorial experiment with varying factors at extreme levels is considered. The formalization of the factors describing the sequence of overloads is proposed.
Structural quality criteria for a surface layer formed by gas pressure nitriding of austenitic steels
Authors: Kuksenova L I , Alekseeva M S , Gress M A , Kozlov D A
Published: January 2021

The tribotechnical efficiency of gas pressure nitriding of austenitic class steels is shown. The characteristics of the structure and operational properties (contact endurance and wear resistance) are given in comparison with cemented steels.
Relation of threshold levels fatigue crack development in low-alloy steel under harmonic and operational loading
Authors: Lebedinsky S , Naumov O
Published: January 2021

The results of experimental studies of the patterns fatigue crack development in samples made of 20GFL steel cut from the cargo over-spring beam are analyzed. The relatio of the threshold stress intensity coefficient Kth, determined from the kinetic diagram of fatigue failure, and the parameters of the threshold level and the operational loading process is estimated.
Local damage to structural materials under low-cycle loading
Authors: Romanov A N
Published: January 2021

The damage accumulation kinetics in plastic (metals) and brittle materials (concrete) at the stages of fracture formation and development under cyclic loading is considered. The regularities of damage accumulation at microlevels due to structural and strain heterogeneity with the achievement of the limit state – the formation of micro-cracks are shownThe early formation curves of micro- and macro-fractures on the fatigue curves, the areas of dispersed fracture formation and development are determined.
Deformation and failure of polymer composites with different layouts under preliminary cyclic and quasi-static loads
Authors: Wildemann V E , Staroverov O A
Published: January 2021

The work presents the results of an experimental study of the mechanical behavior of polymer composite materials (PCM) subjected to sequential cyclic and quasi-static loads at normal temperatures. The methodological features of testing composites under complex mechanical influences are considered. The results of tests for preliminary cyclic and subsequent quasi-static tension of fiberglass specimens with different layouts are given in the fatigue sensitivity’s diagrams. Experimental data have been obtained confirming the difference in the nature of the change in the residual strength of fiberglass with different layouts.
Determination of polymer -substrate joint adhesive strength by means method of pulling fiber from the matrix and normal avulsion
Authors: Sergeev A Yu , Turusov R A , Andreev V I
Published: January 2021

Experimental results of polymer binder adhesive strength -metal substrate joint at shift and a normal detachment are given. It is established that the contact – layer method well describes pull-out tests. The model allows to get the parameters of adhesive joint related to the chosen couple adhesive – substrate, which do not depend on sample geometry. It is shown that the contact-layer method well describes pull-off tests and allows to develop recommendations to sample geometry.
The impact of production temperature of synthetic wollastonite filled with rice husk on its composition and modifying effect
Authors: Gotlib Elena , Tverdov Ilya , Phuong Ha Thi Nha , Sokolova Alla
Published: January 2021

Due to finite reserves of naturally occurring wollastonite, production of its synthetic analog on the base of available and renewable raw materials is of paramount importance. In this aspect, the by-products of cereal-processing industry, in particular, rice husk, command great attention of manufacturers. The properties of synthetic wollastonite manufactured on the base of rice husk ash and limestone are affected by the proportion of these components at the greater extent, as well as the synthesis temperature and time defining its phase composition. In this regard, the authors of the paper have studied the impact of production temperature on the structure of synthetic wollastonite and its modifying effect in epoxy compositions as against naturally occurring mineral. The obtained synthetic wollastonite, regardless the synthesis temperature, primarily contains β-wollastonite and larnite as an admixture. For the cost-effective purposes, the optimum temperature for manufacturing synthetic wollastonite on the base of rice husk ash is 800°C. Both naturally occurring and synthetic wollastonite on the base of rice husk enhance hardness of epoxy coatings, whereas the former one increase it in a greater degree due to a higher presence of β-wollastonite of needle-like particles in its composition.
Selection of Reinforcing Fiber for High-strength Lightweight Concrete for 3D-Printing
Authors: Duong Thanh Qui , Korolev Evgenij , Inozemtcev Aleksandr
Published: January 2021

The knowledge of cement concretes and the availability of raw materials allows them to be used for 3D-printing technology in construction. One of the ways to increase the strength and reduce the shrinkage of the extruded layers is the introduction of reinforcing fibers into the mixture. An important task is the selection of effective types and concentrations of fiber. In this work, research on the selection of such fibers for compositions of high-strength lightweight concrete on hollow microspheres has been carried out. The optimal content of fiber which provides an acceptable decrease in mobility and the greatest strength of concrete is 1.25…1.5 % of the mass of Portland cement. It was found that the studied concretes on hollow microspheres have a reliable connection at the «steel-concrete» interface. The adhesion strength to metal reinforcement with a diameter of 8…12 mm is 6.1… 10.1 MPa with a relative deformation of 0.097…0.025 mm/mm. High-strength lightweight fiber-reinforced concrete has low air permeability parameters, corresponding to the high water permeability grade W20. Such concrete with an average density of 1400 kg/m3 has high frost resistance F1800.
The research of moisture sorption characteristics in mineral wool under the Vietnamese climate conditions
Authors: Nguyen Tien Nam , Grabovy Petr
Published: January 2021

The article discusses the characteristics of the sorption wet steam of mineral wool in laboratory experiments, necessary to determine the change in its mass in conditions of high humidity of the environment, already a country with a tropical climate. The results can be used in new construction and renovation of facades of buildings in Vietnam. A feature of the application of thermal insulation materials in the system of thermal insulation of facades of buildings in different climatic conditions is a factor in the durability of the materials, etc. The climatic conditions of Vietnam have significant features such as high average temperatures, humidity, rainfall, and a long rainy season. These parameters affect the durability and thermal insulation qualities of materials in the thermal insulation system of building facades. The characteristics of moisture resistance of mineral wool, which are used in the systems of ventilated facade construction for thermal protection of buildings in the world in Russia, are considered. In the laboratory evaluation experiments made mineral wool sorption characteristics: extract samples under direct contact with different degrees of relative humidity for a month. This test simulates the effects of a tropical climate in the mineral wool in assembly or during operation, when the protective layer is damaged. The result of the experiment shows the dependence of the degree of sorption of humid vapors of mineral wool on the value of the humidity of the air environment and the time of its direct contact with humid air. According to the results of such experiments can make the choice of building types and technologies insulating materials suitable for the climatic conditions of the Vietnamese during the repair and construction works.
The study of interaction between rubber seed oil and epoxy resin
Authors: Gotlib Elena , Cherezova Elena , Lan Anh Nguyen Thi , Sokolova Alla
Published: January 2021

Plant oils are regarded as relatively cheap renewable and sustainable raw materials that could be efficiently used for manufacturing of glues, coatings, flooring and other materials. Among the plant oils, rubber seed oil (RSO) is of particular interest as it contains the large amount of free fatty acids. development of new innovative cost-effective technologies for processing renewable agricultural products of plant origin is of acute practical importance as they are considered as advanced sustainable raw materials for manufacturing the products of “green” chemistry. According to the literature review, free fatty acids could enhance performance of polymer composite materials, in particular, on the base of epoxy polymers. Having applied the methods of infrared spectroscopy and titrimetry, the authors identified the absence of chemical interaction between epoxy resin and rubber seed oil at room temperature. Having used the data of differential scanning calorimetry, it was stated that epoxy resins react with rubber seed oil at elevated temperatures.
Increasing the technology of waterproofing from bentonite mortars for construction, reconstruction and overall repair of a building
Authors: Korol Elena , Petrosyan Rima , Smirnova Nadezhda
Published: January 2021

Subject: The article investigates the parameters of the technological processes of arranging underground injection waterproofing from bentonite solutions for construction, reconstruction, and overhaul of buildings in cramped conditions, taking into account the features of mechanization of work, the number and qualifications of workers. Based on the results of the timekeeping studies carried out in experimental conditions, the costs of working time for performing technological operations on the arrangement of underground waterproofing with an injection compound from bentonite solutions were determined. Considering the identified technological features, the number and qualifications of workers have been established during the work on the arrangement of injection waterproofing from bentonite solutions.
Thermal conductivity of geopolymer concrete with different types of aggregate
Authors: Krotov Oleg , Gromyko Pavel , Gravit Marina , Belyaeva Svetlana , Sultanov Shukhrat
Published: January 2021

In this article the influence of aggregate of geopolymer concrete used in concrete printing of buildings and structures, architectural elements on its thermal conductivity is studied. All tests were conducted on device for measuring thermal conductivity called PIT-2 designed to measure the thermal conductivity of building and heat-insulating materials under stationary thermal conditions in accordance with ISO 7345:1987* and ISO 9251:1987. As the fine aggregate most commonly used river sand, quartz sand, ceramic foam, as well as one new coniferous shavings were taken. The results of 4 tests to determine the thermal conductivity of geopolymer concrete with various aggregates are listed in the summary table in the study. According to the test results, the lowest coefficient of thermal conductivity has geopolymer concrete on ceramic foam. In this study geopolymer concrete is considered as the main material for concrete printing of the houses and architectural forms. This material reduces CO2 emissions in the atmosphere.
Method for measuring deflections of monolithic floors in conditions of poor visibility of the structure
Authors: Perunov Aleksandr
Published: January 2021

The article shows the method of testing for determining deflections in the slab covering the basement of a residential complex under construction with underground parking. The features of the construction of this section of the building and the reasons for conducting additional research of the erected structures are described. A description of the structures of the studied part of the building, their defects and damages acquired during construction is given. The article describes the methodology and methods used to determine deflections from the control load in conditions of limited visibility due to the presence of mounted engineering systems, as well as restrictions on access to the structure due to the presence of reinforcement elements on its surface. Features of measurements and advantages of combined research methods to ensure the reliability and speed of analysis of the results are described. Based on the results of the research, this article draws conclusions about the possibility of using Express methods for assessing the stress-strain state of building structures, using the example of a residential building with underground parking that has been erected and is being put into operation.
The main causes of accidents of space lattice Kislovodsk-type structures
Authors: Kodysh Emil , Trekin Nikolay , Chaganov Aleksej , Bobrov Vladimir , Shmakov Sergej
Published: January 2021

The article deals with the operation problems of space lattice constructions (SLC) of the Kislovodsk-type, revealed as the results of a survey of more than ten structures within the period from 2000 to 2020. The main causes of accidents of the SLC system was revealed and presented. The disadvantages of production mounting of the Kislovodsk-type system with a hidden capital are considered; the recommendations for preventing the displacement of the SLC support connectors of the Kislovodsk-type system with a hidden capital are presented. As an example, the collapse causes of the Kislovodsk structure made with a hidden capital according to a rare scheme operated in Syktyvkar were analysed in the work. The results of numerical study of the load-bearing capacity of constructions made in CAD SCAD 21.1.1.1 were presented. The most common structural defect of this type – the elements overload of the SLC system is considered in this work. The calculation showed that the structural plate has a three times overload of 35% of the elements (compressive stability, strength). The overload is connected with the normative load increase of snow cover in 2003 and in 2016, and the weighting of the roof structure (twice as compared to the production solution) during its repair work. The load calculation was based on the survey of the SLC constructions. Based on analysis of constructions of this type, the authors give the recommendations on the list of works required for additional inclusion in the survey program of the technical condition of constructions.
Recent experience in solution of geotechnical problems during subway tunneling in Moscow
Authors: Khokhlov Ivan
Published: January 2021

Moscow subway is one of the world’s leaders in transportation. Moscow subway extension is a vital and urgent task for the authorities and engineers. Subway tunnelling requires using new design solutions, techniques and careful planning. However, widespread application of progressive construction methods does not always allow to achieve reliable efficiency in underground subway construction, mostly because of geotechnical risks impact. Mitigation of geotechnical risk becomes an actual task during subway tunnelling, providing security and saving costs and time. The most effective action to avoid geotechnical risk is scientific maintenance, which allows using the previous experience and making careful analysis, to choose the proper construction methods or develop an effective strategy during accidents.
Up-to-date technologies of constructing foundations on loose soil in the city of Moscow
Authors: Abelev Mark , Averin Igor , Karalli Daria , Kopteva Olga
Published: January 2021

The area of residential buildings constructed in various soil conditions in Moscow has amounted to more than 15 million square meters for the past 20 years. Analysis of the work performed in 1990-2010 showed that various design and survey organizations carry out design and engineering surveys in different ways.

Studies of the peculiarities of the construction of various objects in Moscow have shown a high efficiency of the examination of materials for geotechnical and envi-ronmental engineering surveys, as well as design documentation. There are cases when, in the course of construction work, the effectiveness of other, previously not provided for, design and technological solutions is confirmed.

Many possible emergencies of existing buildings, as well as the facilities under con-struction attached to them, unreasonable, expensive and ineffective design solutions were excluded in the process of special examination of the projects.
System of national standards for measuring and evaluating sound insulation
Authors: Tsukernikov Ilya , Shubin I L , Nevenchannaya T O
Published: January 2021

The features of international standards being introduced in the Russian Federation in the field of measurement and rating of sound insulation are considered. It has been noted that over the past eight years, on the basis of international standards, a system of fundamental national standards of Russia has been created to measure and evaluate sound insulation in buildings and elements of buildings and structures. The system includes five standards that establish technical methods for laboratory measurements of airborne and impact sound insulation, a standard that establishes approximate methods for field measurements of airborne and impact sound insulation, two standards for a single-number assessment of airborne and impact sound insulation, a standard that sets the rules for determining and application of the uncertainties of sound insulation measurement. In 2018, 2019, on the basis of international standards, drafts of two national standards were prepared on the methods of field measurements of sound insulation of building facades and their elements and sound insulation of airborne sound between two rooms in a building.
Innovative modular greening system for modern buildings
Authors: Korol Elena , Shushunova Natalia
Published: January 2021

For the sustainable development of the cities and auspicious environment for the life of future generations and the health of residents of the metropolis, it is very important to have not only comfortable housing, but also a healthy environment inside and outside it, and for this it is not at all necessary to live in rural areas. Today life in the city goes by at a very fast pace among the modern buildings. These are indispensable spaces for the life of every citizen, however, for the functioning and proper operation of the entire system of the human, it is necessary not only to move, but also to breathe the clear air. This is possible due to the plants in the urban environment, which are very few, and often the gas content and harmful impurities, together with CO2, exceed the maximum regulatory values in the air. The plants help to reduce them, and thus create a green environment for the population. Innovative modular greening systems for the roofs and facades of modern buildings, developed by the authors, possesses high manufacturability in comparison with competitors and help to the environment in general, which contributes to improving the health and longevity of people.
Expert Recommendations for Energy Improvements in Educational Facilities: Case Study-School Buildings in Azerbaijan
Authors: Mammadova G H , Mammadov N Y , Akbarova S M , Feyzieva G H
Published: January 2021

Energy efficiency and resource saving are the key parts of the state policy in Azerbaijan. They cover all areas of the economy, including the building industry and the educational institutions. Therefore utilizing of innovative architectural design and construction strategies, energy-efficient engineering equipment and renewable energy sources should be raised to the level of the current requirements. In pursuit of this aim, examining and evaluation energy consumption in the educational buildings at their operational stage are ones of the contemporary issues and offering recommendations by the implementation the energy improvements is crucial. This article makes research to find energy efficient opportunities and then suggest proper measures and recommendations for educational buildings, what solutions can be used in schools to reduce their energy consumption. There were examined some school buildings in different climate regions of Azerbaijan. There had been performed energy auditing of them and the results were processed by software. Technical data and results for 2 school buildings in Ujar and Lankaran are given here. The recommendations for energy improvements in educational buildings were proposed by the local experts-architects and auditors. Findings can be used for fulfilling a multi-disciplinary energy audit of any educational buildings.
Eigenwaves propagation in three-layer cylindrical viscoelastic shells with a filler non-uniform in thickness
Authors: Mirsaidov Mirziyod , Safarov Ismoil , Teshaev Muhsin , Nuriddinov Bakhtiyor
Published: January 2021

The paper provides the statement of the problem, the development of a calculation method and an algorithm to solve the problems of propagation and absorption of non-axisymmetric natural waves in layered dissipative-inhomogeneous viscoelastic three-layer cylindrical bodies. A detailed analysis of well-known publications devoted to this problem is given. The paper posed the problem of non-axisymmetric natural wave propagation in three-layer cylindrical shells with fillers, taking into account the theory of hereditary viscoelasticity. Dispersion equations were obtained and the dependence of the phase velocity on the wavenumber for the three-layer shells was constructed. A calculation method was developed based on the Muller, Gauss, and orthogonal sweep methods. The program (in C++ language) was compiled based on the developed algorithm. Numerical results were obtained for the complex phase velocity depending on various wavenumbers and parameters of an axisymmetric cylindrical mechanical system for the Kirchhoff-Love and Timoshenko hypotheses. The change in the real and imaginary parts of the complex phase velocity under various parameters of the system was investigated for structurally homogeneous and inhomogeneous mechanical systems. The results obtained by the Kirchhoff-Love and Timoshenko hypotheses are in good agreement but differ in the wave absorbing abilities. It was found that a decrease in filler thickness at a rigid inner shell leads to a rapid increase in the real and imaginary parts of the vibration frequencies.
Application of the theory of strength of materials to determine the shear stresses in beams with round holes
Authors: Saiyan Sergey , Paushkin Alexander
Published: January 2021

A study was carried out of the possibility of applicability of the theory of strength of materials to determine the shear stresses arising in sections weakened by perforation in the form of round holes, depending on the perforation parameters with a constant shearing force along the length of the beam. A method was proposed for the implementation of the Zhuravsky’s formula for a section weakened by round holes, in the form of dividing the cross section into two independent parts and determining the maximum shear stresses by methods of strength of materials. The reliability of this approach is confirmed by finite element analysis in the ANSYS Mechanical APDL software package. The results obtained can be used to determine the maximum shear stresses in perforated beams in cross-sections along the center of the cut.
Specifies of construction industry terminology and methods of analysis of the natural language sentences similarity by using isomorphism of their structures
Authors: Sak Alexander
Published: January 2021

This article discusses methods of automatic translation by analogy. Each dictionary entry in the online dictionary contains a certain number of examples highlighting the use of this lexeme in different contexts. The purpose of this study is to find an example from an online dictionary that most fully conveys the meaning of a word in a particular context. Based on the fact that natural language sentences can be represented as graphs, the author considers several methods based on set theory, graph theory and linear algebra to compare sentences in order to find the closest example in meaning. In addition to purely formal comparison methods based on syntax, the author presents methods for analyzing sentences based on the semantics of their components. The balance between syntactic and semantic structure when comparing sentences gives the best result for finding the correct meaning of the predicate, which ensures an adequate transfer of the idea of the sentence during translation.
Study of wave processes in elastic beams and nonlinear differential equations with moving singular points
Authors: Orlov Viktor , Gasanov Magomedyusuf
Published: January 2021

The main issue for building structures is to ensure its integrity. This is to some extent ensured by the study of wave processes in building structures using mathematical modelling and the identification of model parameters that guarantee the reliability of such structures. The article continues the study of wave processes in elastic beams on the basis of nonlinear differential equations previously published by the authors, in which the existence and uniqueness theorem was proved. At the same time, a feature of the nonlinear differential equation, a movable singular point, was associated with the location of the destruction of the structure. This paper presents a theoretical substantiation of the influence of the disturbance of a moving singular point on the structure of the analytical approximate solution. A priori estimates are obtained and numerical experiments are carried out, confirming the theoretical propositions.
Numerical simulation of fluid-structure interaction by the example of a flow past a cylinder with a flexible thin structure
Authors: Lantsova Irina
Published: January 2021

This article is devoted to the study of a numerical method of modelling fluid-structure interaction (FSI) problems, namely, optimization of computational resources. We consider a flexible thin-walled structure with clamped behind a fixed rigid non-rotating cylinder installed in a water channel. To solve the problem the “2-way FSI” mode of modelling in software ANSYS was used. The results are presented in tables and graphs in comparison with the data of the experiment and other authors.
Non-stationary temperature field of the heating device in the conditions of unsteady thermal field of the space
Authors: Akhverdashvili Robert , Gulkanov Aleksandr , Modestov Konstantin
Published: January 2021

The trend of the modern world is aimed at improving the energy efficiency of buildings and reducing unnecessary costs of heat and electricity. In view of this, heating systems are used with a periodic operating time, in order to reduce the cost of heat energy during periods of absence of people. As a result, this paper will consider a method for determining the temperature of a heating device, taking into account the heat accumulation by the metal body of the device and the heat carrier inside it, with changing environmental parameters, which will allow taking into account the accumulated heat during the heating system operation.
The fractional derivative type identification for the modelling deformation and strength characteristics of polymer concrete
Authors: Kirianova Ludmila
Published: January 2021

The article contains the comparative use analysis of fractional derivative three types (Riemann -Liouville, Caputo and model) at the Begley -Torvik equation when modeling the deformation and strength characteristics of polymer concrete. We also consider how to obtain a solution to the Begley -Torvik equation initial value problem for the fractional derivative model using a recurrent kernels sequence. Further, the correctness is substantiated of establishing the type and the fractional derivative order at the Begley -Torvik equation initial value problem.
Interpolyation in smoothing tin model of the earth
Authors: Inamov Aziz , Ruziev Ilkhom , Nurjanov Saatbay
Published: January 2021

This article deals with engineering (strategic site construction, buildings and structures, material cultural heritage sites), project (underground and overhead pipelines, railways, roads, power lines, fields and minerals, irrigation networks, hydraulic structures). Improved interpolation techniques for determining the most commonly used measuring heights in the process of land surveying, solving engineering problems on topographic maps and surveying land cadastral works (agriculture, fisheries) and the state cadaster illuminated. In addition, design of linear, dotted and field-themed objects, the study of absolute heights for volume measurements, the analysis of survey results in software for the geo-information system, the mapping of Earth’s dimensions, the determination of unknown altitude and land grinding. Optimized using an improved formula for implementation. In addition, there is a section with a relief section height within each relief interval, and traditional methods used to determine intermediate values have caused discomfort to specialists or users of this formula. In this paper, it is widely used that the formula developed can be used to develop a high-precision study of the absolute value of an unknown height and to develop a sequence algorithm for the implementation of modulation systems in the geo-information system family software.
Estimation of a motion equations system of a potential two-dimensional in a water flow plan to dimensionless form
Authors: Kondratenko Anatoly , Alexandrova Marija
Published: January 2021

In terms of stationary open water flow, the boundary conditions in the flow free spreading problem are reduced to a dimensionless form by the various coordinates and flow parameters’ transformations, including I.A. Sherenkov’s transformations, which bring the boundary value problem to a dimensionless form. It was found that the equations system itself can be reduced to a universal dimensionless form, but the boundary problem cannot be reduced, since the boundary conditions both at the flow outlet from a free-flow pipe and at the flow infinity downstream are not reduced to a universal dimensionless form. It is concluded that it is impossible to solve the boundary value problem once and then use this solution under any boundary conditions. It was also revealed that the problem solution depends on a dimensionless parameter-the Froude criterion at the flow outlet from the pipe. This proves that it is possible to build a universal graph, a universal method for solving the problem with Froude numbers at the flow outlet from the pipe more than unity or close to unity. But increasing the Froude number, it is necessary to build a series of graphs, and it is better to create a single theory, an algorithm for solving this problem.
Determination of calculating stresses on the depth of loess grounds of hydraulic structures
Authors: Xujakulov R , Rahmatov M , Nabiev E , Zaripov M
Published: January 2021

The processes of deformation and moistening of subsiding soils are closely related to each other. On the one hand, the deformations of subsiding soil depend on the degree of its moisture content, and on the other hand, they seriously affect the regularities of the process of moistening the massif. In connection with this, the improvement of methods for calculating the deformations of loess bases of hydraulic structures requires a thorough study of the process of moistening the massif and the influence on this process of the specifics of the impact and irrigation structures on the soil. The article presents the results of studies to determine the stresses on the depth of the loess bases of hydraulic structures in the Karshi steppe. It was established that the lateral pressure coefficient reaches its maximum during the period of the most intense manifestation of subsidence in the layer under consideration.
Research of the parameters of contour blasting in the construction of underground mining works in fast rocks
Authors: Norov Yunus , Karimov Yokub , Latipov Zuhriddin , Khujakulov Amirjon , Boymurodov Najmiddin
Published: January 2021

The article develops a methodology for studying the parameters of contour blasting during the construction of underground mine workings in hard rocks. Research has established the effect of the distance between the contour holes and the influence of the values of the coefficient of approximation on the efficiency of contour blasting.
Trajectory of sediment deposition at the bottom of water intake structures of pumping stations
Authors: Urishev B , Artikbekova F , Kuvvatov D , Nosirov F , Kuvatov U
Published: January 2021

The study of the causes and patterns of sediment deposition at the bottom of water intake structures of pumping stations, the negative impact of sediments on the efficiency of their operation is one of the important measures taken to improve the efficiency of the water recovery system. The issues of studying the determination of the deposition rate and the trajectory of solid particles at the bottom of structures were analyzed, and the main shortcomings and shortcomings in determining the parameters of particle deposition were identified. An equation is proposed that allows determining the trajectory of solid particles deposition taking into account their concentration in the flow, the main properties (density, geometric parameters) of particles and water flow, as well as the design dimensions of the pump station’s advance chamber. The obtained calculated results based on the proposed equation were verified by the results of the study of deposits at the bottom of the advance chamber of the operating pumping station, which showed that the spread of the obtained data does not exceed 7…12 %. At the same time, the smallest particles settle at the end of the prechamber in the water suction zone. The obtained data showed the possibility of using the proposed equation to determine the trajectory of sediment particles deposition at the bottom of water intake structures of pumping stations.
Mathematical modelling of bottom deformations in the kinematic wave approximation
Authors: Krutov Anatoly , Choriev Ruzimurod , Norkulov Bekhzod , Mavlyanova Dildora , Shomurodov Anvar
Published: January 2021

Two possible approaches for generalizing the kinematic wave model for deformable channels are being discussed in this paper, including the approximation in which the law of conservation of fluid mass includes erosion and sedimentation; and approximation that the fluid flow is determined by the kinematic wave equation without taking into account bottom deformations.

Systematic comparison of the results of calculations of self-similar waves for different values of the change in water flow was carried out as well.
Heli-drying units for drying fruit and vegetable products under conditions of Uzbekistan
Authors: Shaimardanov B , Abdurokhmonov Sh , Abdurokhmonova Sh , Ibragimova G
Published: January 2021

The article presents the results of research of solar drying plants for mechanization of preparation processes and organization of the drying process with a minimum energy consumption and maximum quality of finished products. The greatest effect is achieved when drying to low humidity, for example, drying fruit to a humidity of 2.5-3% is achieved in 4-16 hours, depending on the properties of the material to be dried. During vacuum drying, the rate of moisture evaporation increases, since the rate of moisture removal is proportional to the difference in water vapor pressure at the surface of the material and in the surrounding space. The efficiency of the process increases due to the lack of heat loss with the outgoing air.
Mathematical modeling of a hydraulic hitched system of gantry tractor with high clearance used in horticulture and viticulture
Authors: Shermukhamedov Abdulaziz , Annakulova Gulsara , Astanov Bekzod , Akhmedov Sh A
Published: January 2021

A mathematical model that allows comprehensive calculation of hydraulic hitched system (HHS) operation of a four-wheel gantry tractor with high clearance was developed in the paper. Analytical dependencies of angles, angular velocities and angular accelerations were determined, as well as the analogs of linear and angular velocities and link accelerations based on the kinematic diagram of the HHS hitch mechanism. A method for complex calculation of the HHS and a computer program using the Pascal algorithmic language were proposed on the basis of developed mathematical model. The changes in values of the driving force and re-sistance force on the hydraulic cylinder rod and the changes in fluid pressure in the hydraulic cylinder were calculated.
Free movement of mineral fertilizers and their mixtures in air
Authors: Khudayarov Berdirasul , Mambetsheripova Ajargul , Kuziyev Ulugbek , Sarimsakov Bakhtiyar
Published: January 2021

The object of research is the free movement of mineral fertilizers and their mixtures in the air after discharge from the centrifugal pneumomechanical apparatus, followed by the processes of distribution on the field surface.

The aerodynamic properties of the grains of mineral fertilizers or mixtures are different. Therefore, they are broken down into fractions during free movement in the air after being thrown from the centrifugal apparatus. A new pneumomechanical type equipment scheme was developed, developed and field tests were carried out using the method of assembling structural elements and the rules of classical mechanics, dedicated to the analysis of technological processes of centrifugal devices in existing and patent information materials and quality spraying of fertilizer mixtures. The expression was derived and calculated taking into account the fact that the rate of additional air flow decreases with distance, and the relative velocity of the fertilizer grains relative to it.

The centrifugal pneumomechanical device is designed to perform two functions simultaneously, the first is to throw mineral fertilizers, the second is to create an additional air flow and direct it behind the thrown fertilizer grains. The proposed centrifugal pneumomechanical type apparatus ensures even distribution of component fertilizer mixtures of different sizes, shapes and densities on the field surface.
Achievement of electric energy savings through controlling frequency convertor in the operation process of asynchronous motors in textile enterprises
Authors: Baratov Rustam , Pirmatov Nurali , Panoev Abdullo , Chulliyev Yakubjon , Ruziyev Sodiq , Mustafoqulov Almardon
Published: January 2021

In article are brought frequency regulation of the asynchronous electric motor and that reach to energy saving itself. Frequency management is energy saving so regulation of the frequency of the rotation of the asynchronous engine are provided increasing coefficient of efficiency and reduction of the loss to powers. A machine asynchronous is often used today as a power scale ranging with a motor from some Watts to several thousand kW. For power applications exceeding several kW, asynchronous motors run solely on three-phase AC power supplies. Owing to the sensitivity of a process or the critical nature of certain applications, the network may be supported with an Uninterruptible Power Supply.
Development of a front plow with active and passive working bodies
Authors: Mamatov F , Mirzaev B , Mirzahodzhaev Sh , Uzakov Z , Choriyeva D
Published: January 2021

The existing plows of smooth, furless plowing do not ensure efficient use of the power of energy-rich arable tractors, high-quality soil preparation for sowing and an increase in the productivity of the unit. The aim of the study is to substantiate the parameters of the active working body of the combined frontal plow, which ensures the efficient use of the power of energy-saturated arable tractors, high-quality soil preparation for sowing and an increase in the productivity of the unit. A constructive scheme of a combined frontal plow with active working bodies has been developed. Analytical dependencies are obtained that describe the process of interaction of an active working body with the soil and, on their basis, rational parameters of an active working body are determined. In the research, the laws and rules of theoretical mechanics, mathematical statistics, mathematical planning of experiments and methods of strain gauge were applied. It was found that when the active working body of the combined plow is in the form of an active cutter, its diameter is 572 mm, the number of knives is 5 pieces, the length of the knives is 16 cm and the sharpening angle is 20°, the required quality of plowing is ensured with the least energy consumption. In this case, the longitudinal distance from the nose of the body share to the shaft of the active working body of the combined frontal plow should be 3 cm, the indicator of the kinematic operating mode of the active working body – 2.19 the transverse distance between adjacent working bodies along the shaft of the active working body -26 cm.
Features of contact interaction of composite polymer materials with raw cotton in the process of friction
Authors: Eshkobilov Kh , Negmatov S , Abed S , Gulyamov G
Published: January 2021

Based on modern concepts of the theory of wear and tear in the course of studying the process of contact interaction of composite polymer materials with raw cotton, a molecular-mechanical-electrical theory of contact interaction is put forward, which reveals the influence of the electrical components of the friction forces on the mechanism and nature of friction.
Autonomous hybrid solar-heat pump for system heat-cooling in buildings
Authors: Anarbaev Anvar , Koroly Mexriya
Published: January 2021

In this paper, there is described technical desicion of heat-cooling supply in building by using the solar heat pump system. It is possible to realize a system having high reliability in operation of the system. The solar heat pump system according to the present technical desicion has high energy efficiency while ensuring reliability, and is useful as a domestic air conditioning and heating water heater. It can also be applied to uses such as industrial heating and cooling devices. In addition, the structure of the autonomous hybrid system according is useful as a method for efficiently using PV system.
Preparation and characterization of rabbit hair keratin hydrogel
Authors: Ge NaiWei , Zhang Yi , Zhang Hao , Zhu Ruoying , Shi Xueping
Published: January 2021

Protein-based hydrogel with the characters of environmentally friendly, resource saving and excellent biocompatibility has become a hot topic in the field polymer materials. In this paper, the rabbit hair keratin was extracted from waste rabbit hair ang then prepared into hydrogel by means of heating-cooling. The conclusion is that the molecular weight of rabbit hair keratin measured by SDS-PAGE concentrated in 40∼60kDa and rabbit hair keratin hydrogel in 11∼22 kDa. The forming conditions such as concentration and temperature of preparing hydrogel were experimented by using variable-controlling approach, the formation concentration of keratin should be over 125mg/ml and the temperature over 55°C. Various characterization techniques were used to determine the physical and chemical property of the hydrogel. As proved by scanning electron microscopy (SEM), covalent bonds and three-dimensional porous structure with many interconnected pores had been successfully formed. They were also characterized by thermogravimetric analysis (TG) and swelling test, etc. The consequence showed that the equilibrium moisture content can reach up to 20.21% and the swelling rate as high as 9.55%, which were inversely proportional to the concentration of keratin. Furthermore, the hydrogel had good thermal stability, the initial decomposition temperature is around 204°C. It is indicating that the excellent properties of rabbit hair keratin hydrogel can be further studied.