bluuebunny/crossref_metadata_2025 huggingface dataset:
Dependence of stress-strain state of hydraulic structures on infiltration moistening of foundation soils
Authors: Xujakulov R. , Samandarova G.
Published: August 2023

As is known, loess subsidence soils are widespread on the globe; their area in Europe and Asia is more than 13 million sq. km. Many of the loess rocks are also located in Central Asia, including the Republic of Uzbekistan. The practice of irrigation development of loess lands shows that the disruptions that have occurred so far in the operation of hydraulic structures (HTS) are due to insufficient knowledge and neglect in designing the features of joint work and interaction structures with their subsidence foundations. The design of hydraulic structures also does not fully consider these features. To ensure the long-term, reliable, and economical operation of hydraulic structures on subsiding soils, it is necessary to improve their design and construction methods, considering the peculiarities of interaction with loess foundations. This article deals with the features of infiltration soil moistening from channels and structures on them.

The article deals with the features of the infiltration moistening of soils from canals and structures on them. Based on the analysis of previous studies, the specificity of infiltration in loess soils is considered a serious factor affecting the stress-deformed state of hydraulic structures and their foundations.
Use of jet pump in vertical drainage systems
Authors: Rakhimov K. , Sultanov R.
Published: August 2023

Usually, vertical drains are widely used to improve land reclamation and construction of urban planning, transport and road construction, and agriculture. Vertical drainage systems are drainage systems that use pumped wells, open dug wells, or tube wells. There are calculation methods based on pumping curves and calculation methods based on the filtration equation of hydraulic calculation of vertical drainage. In the proposed system, jet apparatus is used in vertical drainage systems. Jet pumps are designed in such a way that they transfer the impulse through the high-speed primary to the secondary flow. Jet devices are widely used in agriculture, mining, oil extraction, and various industries. In addition, they can be used as an independent units or together with pump units.
Engineering and geological conditions of dam construction
Authors: Balabanov V. , Zhizdyuk A. , Karpov M. , Khudaev I. , Norov B.
Published: August 2023

The article presents studies of the engineering-geological conditions of dam construction, consisting of the structure of river valleys and slopes, conditions of rock occurrence, geotechnical and filtration properties of rocks, and geological conditions of the dam construction site. A classification of valley types with schemes, classification of rocks about the location of dams, and types of tectonic structure of valleys about the construction of dams are presented. Conclusions are drawn about the most favorable and unfavorable conditions for the construction of dams.
Shafts of technological machines with combined supports
Authors: Yunusov S. Z. , Kenjayev S. N. , Makhmudova Sh. A.
Published: August 2023

This article discusses experimental studies of a saw cylinder (SC) composite shaft with combined support. We proposed a new design of the support that provides a reduction in the shaft. The article considers the influence of changing the parameters of the elastic element of the support of the composite shaft (CS) of the SC using the ANSYS software, calculates and analyzes the reaction forces of the supports for different parameters of the elastic elements, and also considers the effect on the stresses of the system, as well as the results of experimental and comparative tests in production conditions on the SC of the cotton gin machines with a composite bearing, where the parameters of the elastic element differ from each other by different elasticity. The fiberization process took place according to the established technological parameters. The experimental and standard SC models were compared during the experiment.
Influence of nozzle geometry on torch parameters during gas combustion
Authors: Khodjiev S. , Pirimov A. , Avezov A. X.
Published: August 2023

In this paper, when performing and analyzing the series of calculated results of the analysis of the sides of a rectangular nozzle for the parameters of a turbulent free air jet and a flame of a propane-butane mixture based on three-dimensional parabolic Navier-Stokes bonds for multicomponent reacting jets. To estimate the turbulent viscosity, differential equations of the kinetic and dissipation of the kinetic energy of turbulence are observed with refined empirical constants that are acceptable in turbulent combustion, as in the calculations, the initial values of the kinetic energy of turbulence did not exceed 5% of the dimensionless velocity of the main jet. It was found that when an air jet flows out of a nozzle with an aspect ratio of (1:2) and (1:4) in the initial sections of the jet, its shape behaves like an ellipse and, with the distance, it turns into a round one, with dimensionless, x greater or equal to 20 for the nozzle (1:2) and x greater or equal to 30 for (1:4), and for this variant there is again a transition to an elliptical shape. Studies of the diffusion combustion of a propane-butane mixture flowing out of a rectangular nozzle with an aspect ratio of (1:2) and (1:4) showed that with the ratio of the speed of the oxidizer to fuel mu, the flame length increases when mu between 0 and 0.164, and then, with an increase of mu more than 0.41, the torch length is shortened. The axial distributions of the momentum flux density with the aspect ratio (1:4), the jet core is shortened by 2÷2.5 times, compared with the aspect ratio (1:2) with the other parameters unchanged. Setting the tangential velocity at the mouth of the nozzle (ω=6.1 m/s) leads to a decrease in the torch length by 11% compared to its value equal to zero.
Management of consumers needs for volume of transportation, taking into account the probable nature
Authors: Zhuraev Mukhiddin , Togaev Jamshid , Yusufkhonov Zokirkhon
Published: August 2023

The article investigates the issue of continuous provision of consumers' needs for transportation, which is formed by chance. At the same time, the indicators of elementary random processes aimed at satisfying the needs of consumers in transportation were investigated, and corresponding mathematical models were formed for them; methodological properties and aspects of this approach were also substantiated. Based on the cost of transporting raw cotton materials from the Nuriston cotton station to the Nishan cotton ginnery, the reliability of the results of operational planning of transportation and transportation management is considered.

Based on the mathematical models presented in the article, it becomes possible to continuously meet the production needs of an enterprise at any random cost of consumed and transported goods.
Assessment of quality of signal transmission process in focs with DWDM
Authors: Mirazimova Gulnora , Kadirova Laylo
Published: August 2023

The power of a group DWDM signal increases nonlinear interference in the optical path, especially the value of the interference of the FWM. These interfering factors degrade signal transmission quality and can completely disable the WDM system. Therefore, when designing a DWDM system, it is necessary to optimize the power of the transmitted signal to minimize the probability of error in the optical channel. The article presents the research results and analysis of factors affecting the quality of fiber-optic communication systems with wave separation of channels. Selecting the optimal power level of the group signal and evaluating the transmission quality of optical communication channels in WDM allows us to solve the problem of science-based design, implementation, and effective operation of advanced optical communication systems with wave division of channels.
Research on factors affecting highways passing through mountain and mountain areas
Authors: Yadgarov Sirojiddin , To’xtayev Matjon , Xoshimov Iftixor , Yuldoshev Akmalxon
Published: August 2023

In this article, flood floods affecting automobile roads and natural disaster relapse on maps using geoinformation systems. The flood consists of forecasting the arrival. The impact of floods on highways was considered from the studied factors. Flood (Flood current) - a stagnant mud or mud rock stream consisting of a mixture of water and rock fragments that suddenly appear in the basins of small mountaineers. How to increase productivity, increase movement, increase the duration of movement, reduce work time), reduce the impact of a natural disaster. Floods threaten settlements, railways, highways, and other structures. This regional model was developed specifically for Uzbekistan and offered an extremely high spatial and temporal resolution of the data. This is necessary for realistic and meaningful simulations.
Purification of borehole and domestic waters in rural conditions of Uzbekistan using filters and their hydraulic calculation
Authors: Obidjonov Axror , Umarov Uchkun , Babaev Askar , Quvondiqov Quvonchbek , Umarova Dinara
Published: August 2023

One of the main factors of human life is water, because more than 70% of the human body is water. In a situation where there is a shortage of fresh water around the world, there are increasing problems waiting to be solved, such as protection of water resources, effective use, and prevention of changes in their physical and chemical conditions. Environmental pollution also affects groundwater. Direct consumption of groundwater also has negative effects on the body in many cases. This article develops recommendations for specific amounts of groundwater treatment. Experimental tests were carried out and hydraulic calculations were carried out for the use of gravel and quartz sand, which are local raw materials, as filter load. The retention of organic and inorganic substances in a certain amount when water is passed through the filter load has been proven in experiments, and the results of the conducted research are presented in the article.
Bending-torsional vibrations of aircraft wing
Authors: Khudayarov B. A. , Ruzmetov K. Sh. , Turaev F. Zh. , Komilova Kh. M. , Kuralov B. A.
Published: August 2023

The problems of bending-torsional flutter of an aircraft wing are considered. Using equations of motion by the Bubnov-Galerkin method, based on the polynomial approximation of deflections and angle of twist, the problem is reduced to studying a system of ordinary integro-differential equations, where the independent variable is time. The solution of integro-differential equations with singular kernels is found by a numerical method based on quadrature formulas. The influence of physical-mechanical and geometric parameters on the flutter of the aircraft wing was studied. It was established that an account for the viscoelastic properties of the material of thin-walled aircraft structures leads to a 40-60% decrease in the critical flutter velocity. It is shown that an increase in the elongation parameter of an aircraft wing leads to a decrease in the flutter velocity.
Impact of rigid body and viscous-plastic rod of finite length
Authors: Begmatov Abduvali , Mamatova Nigora
Published: August 2023

The impact of a rigid body and a rod of finite length made of a viscoplastic incompressible material moving towards each other at constant velocity is studied in the article. One-dimensional motion is considered, i.e., velocity, stress, and other parameters are considered to be averaged over the rod section. According to the model of a viscous-plastic material, the rod is divided into two parts: the region of plastic strain and the region that moves as a solid body after impact. The boundary between these regions is unknown and needs to be determined. As a result, we arrive at a problem with a free boundary, a well-known example of which is the Stefan problem. However, the formulation of the problem under consideration differs significantly from the Stefan problem. In addition, the function to be determined that describes the unknown boundary, in contrast to the Stefan problem, is not explicitly present in the boundary conditions. There are various numerical methods for solving problems with an unknown moving boundary. However, as is known, implementing these methods is associated with significant difficulties. In this article, the method of integral relations is used - a modification of the Karman-Pohlhausen method known in the boundary layer theory. The problem is reduced to the Cauchy problem for a system of nonlinear ordinary differential equations proposed to be solved by successive approximations and the Runge-Kutta method. Numerical calculations were performed. The influence of changes in the mass and magnitude of the velocities of the rod and rigid body on the size of the plastic strain region and the change in stresses on the contact surface is revealed.
Analysis of soil salinity in irrigated agricultural land using remote sensing data: case study of Chinoz district in Uzbekistan
Authors: Oymatov Rustam , Teshaev Nozimjon , Makhsudov Rahimjon , Safarov Fayzali
Published: August 2023

Soil salinity is a serious agricultural concern in Uzbekistan, causing plant growth to be hampered and crop productivity to be diminished. This issue is especially prevalent in semi-desert and desert regions, compounding problems such as soil erosion, land degradation, subsidence, corrosion, and poor groundwater quality. On the other hand, Geographic Information Systems (GIS) and Remote Sensing (RS) technologies provide more efficient, cost-effective, and timely tools and procedures for mapping soil salinity. Different indices and methods can be used to detect and quantify soil salinity levels using the spectral information acquired by the Landsat-8 OLI sensor. Among these are the Normalized Difference Salinity Index (NDSI) and the Normolazed Difference Vegetation Index (NDVI). GIS software integrates satellite imagery with auxiliary data such as soil type and topography, allowing for a thorough assessment of soil salinity distribution over the research area. Compared to traditional methods, integrating remote sensing data with GIS analysis provides a more efficient and cost-effective approach to soil salinity assessment. The findings of this study will help us understand the distribution of soil salinity in the study area and provide insights for decision-making processes connected to sustainable land management.
Modeling of hydrogeological processes in irrigation areas based on modern programs
Authors: Abdullaev B. D. , Razzakov R. I. , Okhunov F. A. , Nasibov B. R.
Published: August 2023

This article uses modern modeling systems to assess the impact of intensive irrigation on the state of groundwater and the rocks of the aeration zone. In doing so, existing ideas about aquifer recharge, flow, consumption, and changes in groundwater quality were considered, studying these areas' hydrogeological and reclamation hydrogeological conditions. Groundwater balance analysis was performed based on the results of solving the inverse non-stationary problem for total groundwater deposits. The correspondence of underground water at control points during this period (results of regular observations of Kashkadarya GGS) and underground water seeping into the collector-drainage network in natural and model conditions was observed. According to the research results, renewable (flowing) underground water reserves in the general balance are 15671-2476 = 13195 m3/day, while the indicators of consumption and saturation of underground water reserves are equal to 2476 and 8915 m3/day. It was proved based on the results obtained with sample solutions to the problem, taking into account the rise or fall of the level of underground water in different parts. The article determined that the accumulation of underground water reserves in the region is mainly due to the increase of infiltration in newly developed lands. At the beginning and end of the modeling period, the depth of the groundwater table was shown using maps and marked with numbers.
Pulsating flows of viscous fluid in flat channel for given harmonic fluctuation of flow rate
Authors: Navruzov Kuralboy , Turayev Muhammadi , Shukurov Zoxid
Published: August 2023

In research work, it is pointed out the issue of a pulsating flow of a viscous incompressible fluid in a flat channel for a given harmonic fluctuation of the fluid flow rate. The study of the generation of pulsating current is used in biological mechanics, in particular, in the use of microchip systems. In addition, to ensure a constant flow of liquid, pneumatic micropumps that periodically squeeze liquid from empty volumes are widely used. In such systems, the installation of pulsating flow is shown to be economically beneficial. The transfer function of the amplitude-phase rate response is determined; with the help of these functions, the ratio of the tangential shear pressure on the channel fence to the average acceleration over the channel section is determined. In Figure 1, it can be seen that the ratio of KH = 0 of in τHC/τ0KC is close to one and α02 is less than one. If α02 takes on values greater than unity, then the ratio of to KH = 0 to τHC/τ0KC is greater than unity, and it has been shown to increase with increasing frequency of dimensionless oscillation. It was shown that in an unsteady flow of liquid, even in cases where liquid acceleration is equal to zero, it was studied that the stress on the wall of the channel exceeds its quasi-stationary value. τHC/τ0KC with the increase of the ratio KH, the increase of the parameter is explained by the fact that the change of the tensile stress on the wall advances in phases concerning the average speed along the section. Calculations determine that the non-stationary shear pressure on the channel fence increases non-monotonically with the acceleration of the liquid particle at low oscillation frequencies. The shear pressure reaches its maximum value, then decreases with increasing dimensionless oscillation rate, and asymptotically approaches the values without accelerated flow.
Adsorption properties of carbon adsorbents based on wood waste
Authors: Paygamov Rahimjon , Mexmonxonov Mansurhon , Abdikamalova Aziza , Eshmetov Izzat , Ergashev Oybek
Published: August 2023

This article investigates the adsorption properties of carbon adsorbents obtained from wood waste. The work aimed to study the effect of heat treatment and steam activation on the structure of coal and its ability to adsorb benzene. Electron microscopic, X-ray phase, and IR spectral analyses were carried out to achieve this goal. The results of electron microscopic analysis showed that the grain size of sample FK-600 was smaller than that of other samples. Still, the surface morphology of all solids was characterized by roughness and unevenness. Particularly heterogeneous surface morphology was observed in steam-treated activated carbons, indicating strong oxidation. X-ray phase analysis showed the presence of carbonate and silicon salts of metals in adsorbents obtained at 400 and 600°C. IR spectral analysis made it possible to reveal functional groups on the surface of carbon adsorbents. Thermal treatment and steam activation changed the number and type of functional groups. This work studied the influence of heat treatment and steam activation on the structure of coal and its ability to adsorb benzene. The analysis of adsorption isotherms showed that the adsorbents have a microporous structure and exhibit type I Brunauer isotherms. Experimental data indicate a significant increase in the specific surface area and adsorption volume with increased activation temperature. Heat treatment at higher temperatures and steam activation also contribute to opening additional pores in carbon adsorbents. The results obtained allow a deeper understanding of the interaction of carbon adsorbents with benzene and optimize the processes for obtaining such adsorbents based on wood waste. This is of great practical importance for water and air purification from organic pollutants and may lead to the development of more efficient and environmentally friendly purification methods.
Sources of alternative types of energy in system of hydro-engineering structures of angrenskaya mine of brown coal
Authors: Yakubov Salimjon , Khasanov Bakhriddin , Muratov Ashirbek , Yunusova Farida , Atajanova Donobuvi , Choriev Alibek
Published: August 2023

Along with the development of traditional energy in Uzbekistan, much attention is paid to alternative and renewable energy. The Angren Special Economic Zone, on the one hand, is a catalyst for the development of industrial production, the creation of new innovative technological enterprises, the strengthening of logistics processes, and the improvement of the city's living standards. All this requires the search for new sources of energy resources along with an increase in coal production. Unique hydraulic structures currently serve to ensure the functioning of the Angrenskaya coal mine. Analysis of individual technological hydrotechnical facilities made it possible to determine the availability of alternative energy sources. The paper provides some considerations on using these sources for energy generation using small hydropower plants. The average calculated indicators and energy potentials of alternative energy sources are presented. Some hydraulic turbines are considered within the framework of the hydraulic engineering systems.
Problems of climate change and efficient use of water resources in the Aral region
Authors: Urazbaev Ilkhom , Khamidov Akhrorxon , Khasimbetova Saltanat , Khamidov Mukhamadkhan
Published: August 2023

This artiсle рresents the results of sсientifiс researсh on сlimate сhange in the Aral Baу region due to global сlimate сhange and inсreasing water sсarсitу, as well as the develoрment of сotton irrigation methods taking into aссount soil-hуdrogeologiсal сonditions. In the Reрubliс of Karakalрakstan, whiсh is loсated in the Aralboуi region, global сlimate сhange рaрametрlaрin Biр diversitу and T-test analуsis revealed an inсrease in aсoсida air haрoрathу bу 1.42°C, and the sсientifiс-based irrigation рroсedure of сotton “Methodologу of сonduсting field exрeriments” of the Sсientifiс Researсh Institute of Cotton Seleсtion, Seeding and Cultivation Agroteсhnologies (2007 )” on the basis of the VIII hуdromodule with the largest area in the region was develoрed for the region, and it was found that irrigating сotton 4 times in the 1-2-1 sсheme with irrigation norms of 623-882 m3/ha and seasonal irrigation norms of 2789-2867 m3/ha is highlу effeсtive.
Cross-diffusion systems with convective transport
Authors: Muhamediyeva Dildora
Published: August 2023

The properties of cross-diffusion systems, which have double nonlinearity and include convective transfer, are investigated. This means that two factors are taken into account in the system: diffusion (random movement) and convection (transfer with the participation of the medium flow). The study of the properties of such systems makes it possible to understand how the interaction of these factors can influence the behavior of a population. The simulation of the processes of multicomponent cross-diffusion systems of a biological population with convective transfer on a computer is described. This means that with the help of numerical methods and computer models, models have been created that make it possible to simulate and study these systems. Such modeling helps to get an idea about the behavior of a cross-diffusion system under various conditions and system parameters. Estimates are obtained for solving the Cauchy problem of multicomponent cross-diffusion systems with convective transfer, which are analytical estimates of solutions. The study of the qualitative properties of the system made it possible to perform a numerical experiment depending on the values included in the system of numerical parameters.
Mathematical modeling of hydrodynamic resistance in an oscillatory flow of a viscoelastic fluid
Authors: Navruzov Kuralboy , Rajabov Suxrob , Ashurov Muzaffar
Published: August 2023

The problems of the oscillatory flow of a viscoelastic fluid in a flat channel for a given harmonic oscillation of the fluid flow rate are solved based on the generalized Maxwell model. The transfer function of the amplitude-phase frequency characteristics is determined. Using this function, the dependence of the hydrodynamic resistance on the dimensionless oscillation frequency is studied for various values of the elastic Deborah number and the concentration of the Newtonian fluid. It is shown that in an oscillatory flow of a viscoelastic fluid, the hydrodynamic resistance decreases depending on the Deborah number. With an increase in this number, the decrease becomes more pronounced than before. This effect allows us to evaluate the hydrodynamic resistance for a given law; the change in the longitudinal velocity averaged over the channel section and for the motion of a viscoelastic fluid in an unsteady flow allows us to determine the dissipation of the mechanical energy of the medium, which is important in the regulation of hydraulic and pneumatic systems.
Estimating Scheme Viscosity for Small-Scale Circulation with Implicit Finite-Difference Schemes
Authors: Salokhiddinov Abdulkhakim , Savitsky Andrey , McKinney Daene , Ashirova Olga
Published: August 2023

The article proposes a formula for calculating scheme viscosity, which manifests itself in calculations using implicit schemes for calculating the transfer of matter and momentum. The study aims to substantiate the structure of the formula for calculating the scheme viscosity using implicit schemes for calculating the mass and momentum transfer equation. As a result of the study, the structure of the formula for calculating the scheme viscosity for implicit schemes for solving the transfer equation was determined. The accuracy of the formula was checked on a test example. It is substantiated that by all possible means, it is necessary to avoid using implicit schemes when solving problems of small-scale circulation within urban areas. The manifestation of scheme viscosity in calculations of small-scale circulation, in which small pressure drops provide air movement, is unacceptable due to the many times the greater effect of scheme viscosity over natural viscosity.
Norms according to international roughness index of road pavements in Republic of Uzbekistan
Authors: Ablakulov A.
Published: August 2023

This scientific article presents an analysis of the norms of the roughness of road pavement in foreign countries. Based on the results obtained from the experimental research work on measuring the international roughness index (IRI) of road pavements on many years of various highways by studying their experience, norms on the roughness of road pavements in the Republic of Uzbekistan are recommended.
Evaluation of effect of deviations in width of cross-section of connected elements
Authors: Ergashov Akbar , Shojalilov Shukhrat , Djumaniyazova Rano , Shipilova Kamila
Published: August 2023

The tests were carried out in two stages: at the first stage, the height of the fall of the load was assumed to be insignificant, which did not lead to the destruction of the structure, while its deformation was considered in the elastic stage of the work of materials; at the second stage, the height of the fall of the load was selected based on the condition of bringing the structure to destruction, while the work of the structure in the elastic-plastic stage was studied.
Modeling of segmental excavator working tool for soil compaction
Authors: Khankelov T. K. , Askarkhodzhaev T. I. , Aslanov N. R.
Published: August 2023

The development of a methodology for physical modeling of the working process and a replaceable working tool of an excavator for soil compaction in the construction, maintenance, and repair of man-made engineering structures in confined spaces are considered in the article. This methodology is based on a rheological model of the soil compaction process containing Hooke and Newton's elements connected in parallel (the Voigt model is the method of integral analogs that have been used to obtain the main similarity criteria that adequately characterize the process of static compaction during elastoviscoplastic soil deformation). The formulas for the transition from the model parameters to the parameters of the full-scale process of soil compaction by a segmental working tool are obtained based on similarity criteria for modeling the option without changing soil properties.
Material selection for vehicle brake chamber case with using computer methods of analysis
Authors: Riskulov Alimjon , Nurmetov Khurshidbek , Avliyokulov Jamshed
Published: August 2023

In this paper, we consider options for using computer methods for analyzing the design features of some automotive units, which made it possible to justify the choice of materials and technologies for their manufacture. To improve the performance parameters that determine the service life of brake chamber housings made of a polymer composite material based on polyamide 6, methods for modifying the matrix are proposed that reduce its characteristic disadvantages -increased moisture absorption and a tendency to aging under the influence of atmospheric factors.
Testing wood-composite reinforced specimens for shearing along fibers
Authors: Lisyatnikov Mikhail , Lukin Mikhail , Martinov Vladislav , Roshcina Svetlana
Published: August 2023

With the development of chemical technologies, new building materials and products based on them appear. Such materials are used both in the production of new structures and in the strengthening of existing elements. A method of strengthening with glass and carbon fabrics has proven itself in reinforced concrete structures. We have developed a method for reinforcing high wood-glued beam structures with a polymer composite in the support zones. The composite consists of fiberglass impregnated with epoxy. To increase the strength, carbon nanotubes are included in the polymer composition. To confirm the effectiveness of this amplification, it is necessary to carry out numerical and experimental studies. In order to save labor costs, planning a multivariate experiment and machine tests of standard samples with and without amplification is first carried out. As a result of the test for chipping along the fibers of prototypes, it was found that the tensile strength of reinforced samples compared to wooden ones without reinforcement increased by 49%, which is the optimal value for full-scale tests.
Polymer compositions for restoration of destructed wooden structures
Authors: Lukina Anastasiya , Popova Marina , Sergeev Mihail , Chibrikin Danila
Published: August 2023

Under changing temperature and humidity conditions, organic material is biodegraded by microorganisms, rot appears, and wood is destroyed, which leads to a loss of operational reliability of wooden structure elements as a whole. To maintain the working condition of wooden structures, extend their life cycle, and ensure operational reliability, it becomes necessary to carry out work to strengthen and repair the surfaces of wooden elements. The article’s authors have developed polymer compositions that can be used to restore the bearing capacity. The first composition was developed based on epoxy resin, and the second was based on dimethacrylic polyester. Conducted tests to determine the compressive strength and shearing along the fibers and the adhesive strength in shear and bending of the wood-composite element. It has been established that the compressive and chipping strengths of impregnated samples are comparable to the strengths of "healthy" wood. The developed composition, based on epoxy resin, showed high adhesive-cohesive properties. It is shown that both materials equally provide the restoration of destructed elements and increase their bearing capacity. Science-based technical solutions for the restoration of local areas of destructed wooden structures can be used in projects to reconstruct, repair, and restore wooden buildings and structures.
Earthquake resistance of culverts of railways of Uzbekistan
Authors: Abdujabarov Abduhamit , Begmatov Pardaboy , Mekhmonov Mashkhurbek , Eshonov Farkhod
Published: August 2023

Based on full-scale and model experiments using a seismic platform and vibration disturbances from rolling stock during high-speed movement, additional functions affecting the dynamic stability of the railway roadbed have been identified. The calculation formulas for ensuring the seismic resistance of railway culverts with the determination of the influence of the slope of the terrain of the road and the speed of trains have been clarified. If the core is reinforced with geotextile after 0.5 m, the soil layer above the pipe can be reduced to h = 1.5 m, which significantly reduces the excavation volume and the rail-sleeper grid's slopes. In addition, the magnitude of long irregularities that occur in the pipe area decreases, increasing the repair time of roads and the resistance to seismic forces. When conducting experimental studies on models, when focusing on this coefficient, there is no need to bring the model of the structure to destruction, which saves time and building materials.
Comprehensive solution to environmental problems of ceramic production by recycling their waste in cement industry
Authors: Iskandarova Mastura , Atabaev Farrukh , Mironyuk Nina , Yunusova Farida , Kahhorov Uktam
Published: August 2023

The paper presents the results of studies to determine the suitability of the dump battle of fired ceramic products based on kaolin clays of the Angren deposit, the positive effect of the addition of fractionated ceramic battle on the formation of the structure and physico-mechanical properties of portland cement stone is established. For use as an additive in cement, the need for fractionation of ceramic production waste with separation of the burnt part of ceramic waste was noted; its chemical and mineralogical compositions and hydraulic activity were determined according to the Student’s criterion, the value of which was t=21.21, which is higher than its regulated value of at least 15 according to GOST (State Standard) 31108-2020. Based on the obtained research results, ceramic waste is recommended as an active mineral additive in cement. The positive effect of the addition of fractionated ceramic waste on the process of origin and evolution of neoplasms in terms of acceleration of hydrolysis, hydration of clinker minerals, and cement hardening with the formation of a low-porous structure of cement stone, which, despite a decrease in the proportion of high-temperature Portland cement clinker up to 20%, is characterized by high hydraulic activity corresponding to the grade of cement PC400-D20.
Dynamic buckling of plate made of glass reinforced plastic under rapidly increasing shear load
Authors: Eshmatov Bakhtiyor , Mirsaidov Mirziyod , Abdikarimov Rustamkhan
Published: August 2023

The research object of this work is a clamped rectangular plate made of glass-reinforced plastic. The dynamic problem of stability of the plate under rapidly increasing shear load is considered. Within the Kirchhoff–Love hypothesis framework, a mathematical model was built in a geometrically nonlinear formulation. By the Bubnov–Galerkin method, based on a polynomial approximation of the deflection, the problem was reduced to solving systems of nonlinear ordinary integro-differential equations. With a weakly singular Koltunov–Rzhanitsyn kernel with variable coefficients, the resulting system was solved by a numerical method based on quadrature formulas. The plate’s dynamic behavior was investigated depending on the plate’s geometric and physic parameters. The importance of considering the viscoelastic properties of the material is shown.
Gradient structural-phase states and properties of surface layer after nitro-oxidation
Authors: Eshkabilov Kholikul
Published: August 2023

The phase equilibrium is considered, the formation of nitride phases during gas nitriding due to the presence of carbon in the iron steel matrix in all formed structural-phase states of the nitride layer, carbides are released, the dispersion and dispersion of which in the nitride layer depends on the nitrogen potential of the saturating atmosphere. During subsequent oxidation in water vapor, simultaneously with the formation of a surface oxide film during the exposure period, especially in water vapor with additives of complexion agents, during reaction-diffusion, gradient structural-phase states of low-nitrogen carbonitride, oxycarbonitride, and nitride phases are formed in the nitride layer. At the same time, the presence of oxygen in the furnace atmosphere positively affects the formation of the nitride layer and the internal nitriding zone. The corrosion resistance of gradient nitride-oxide diffusion coatings depends on the presence of a surface oxide layer consisting of magnetite and the ratio of modified nitrides and γ'-phase composition. At the same time, in the composition of the nitride layer, the composition of oxycarbonitrides with a larger proportion of the γ'-phase has the highest corrosion resistance with a lower rate of development of corrosion damage on the surface. The presence of a surface oxide layer in the structural-phase states of the nitride-oxide layer, providing a positive property gradient, can provide conditions for external friction during sliding friction.
Structural-phase transformations during nitro oxidation of steels and surface properties
Authors: Eshkabilov Kholikul
Published: August 2023

Structural and phase changes in the surface diffusion layer during gas nitriding of steel were studied, with the formation of a crystallographic structure of the nitride layer for subsequent oxidation in water vapor. The conditions for forming carbides and nitrocarbides with simultaneous diffusion of nitrogen and decarburization of the steel matrix are determined depending on the nitrogen potential of the saturating medium.

The structural-phase states of the surface diffusion layer with a stepwise change in the nitrogen potential during nitriding at the first stage and followed by oxidation at the second stage, the formation of a surface oxide layer, as well as the conditions for participation in mutual diffusion processes of carbon in the nitride layer, decarburized from the steel matrix with the formation compositions of modified nitride phases.

The nitride-oxide layer’s corrosion properties and gradient properties in various structural-phase states of nitride phase compositions have been studied.
Properties of concrete containing high-calcium fly ash artificial aggregate
Authors: Barabanshchikov Y. G. , Usanova K. Y. , Umarov Sukhrob , Salimbayev Mirsoxibjon
Published: August 2023

The work aims to develop a concrete mixture with cold-bonded fly ash aggregate based on high-calcium fly ash and experimentally study its physical and mechanical properties. The results of experimental studies of concrete with artificial coarse aggregate based on fly ash from Berezovskaya Thermal Power Plant showed compressive strength of 28.92 MPa, flexural strength of 4 MPa, coefficient of linear thermal expansion of 14.5 * 10−6 K−1, modulus of elasticity of 16 *109 Pa, heat of hydration on the 10th day - 340 kJ/kg, shrinkage deformation of −1.8 mm/m. It has been established that heat treatment of fly ash aggregate for 8 hours at a temperature of 80 °C after 7 days of air storage did not positively affect the physical and mechanical properties of concrete. The compressive strength at the age of 28 days and the modulus of elasticity of the specimens with coarse aggregate after heat treatment were lower by 41% than that of the control mixture.
Forced vibrations of hereditary deformable shell elements of aircraft structures in gas flow under influence of atmospheric turbulence
Authors: Usmonov B.Sh. , Safarov I.I. , Teshaev M.Kh. , Nuriddinov B.Z. , Ablokulov Sh.Z.
Published: August 2023

The problem of vibrations of thin, hereditarily deformable shell elements moving in a gas under the action of atmospheric turbulence is considered. The work aims to study the flutter phenomenon of aircraft elements in a gas flow under the action of loads caused by atmospheric turbulence. Assuming that the relationship between stresses and strains for the shell material is linear-hereditary, a thin shell is used, which obeys the Kirchhoff-Love hypothesis. The aerodynamic force is written according to the linearized piston theory. A system of nonlinear integro-differential equations in partial derivatives is obtained to describe nonlinear oscillations of a thin isotropic viscoelastic shell. The system of nonlinear integro-differential equations is solved numerically by the method proposed by F. Badalov, which is based on the Bubnov-Galerkin methods, finite differences, and power series. When using an exponential kernel, the flutter rate increases to approximately 1.5%. Therefore, when using an exponential kernel, the flutter velocity of a viscoelastic shell practically coincides with the critical flutter velocity for ideally elastic plates. It was also found that the critical flutter velocity increases with an increase in the number of pinched sides of the shell.
Selecting wastewater treatment filters using local raw materials
Authors: Umarov Uchqun , Quvondiqov Quvonchbek , Obidjonov Axror , Babaev Askar , Ochildiyev Otabek
Published: August 2023

Currently, in a situation where there is a shortage of fresh water around the world, there are increasing problems waiting to be solved, such as protection of water resources, effective use, and prevention of changes in their physical and chemical conditions. As one of the solutions to these problems, it is considered to make the treatment of waste water suitable for reuse or to achieve it by carrying out theoretical and practical research aimed at discharging ecologically clean water into nature. The article develops recommendations for water treatment and reuse using local raw materials for filter devices widely used in wastewater treatment by small enterprises. Experimental tests and hydraulic calculations were carried out for the use of local gravel, quartz sand, activated bentonite and coal, as well as industrial waste rubber granules as filter load. Taking into account the substances contained in their wastewater, the cleaning parameters were determined and recommendations were developed for the conditions of use. It was proved that the cleaning efficiency of activated charcoal or bentonite filters can be reached up to 90-96% for enterprises with high content of oil-oil products and surfactants. Using quartz sand, gravel, and rubber granules to clean wastewater from suspended matter has been proven to be 92-98% effective in experiments.
Influence of dispersion and content of mineral filler on the structure and properties of gypsum binder
Authors: Turgunbayeva J. R. , Mirzayeva Z. M. , Hakimova Yo. T.
Published: August 2023

The effect of dispersion on the structure and properties of gypsum binder and the content of mineral filler from industrial waste (15%) - crushed steel-smelting slag from the mass of gypsum binder was studied. With the introduction of the optimal amount of filler, in turn, it can significantly improve the macrostructure of the composite, increase the strength of the gypsum stone by 20%, despite the reduction in the consumption of gypsum binder up to 25%. At the same time, their strength characteristics are preserved, relative to the gypsum binder without filler. The resulting gypsum binder can be used in the manufacture of gypsum tongue-and-groove boards for the construction of partitions in rooms with normal humidity.
Investigation of stress transfer through cracks in reinforced concrete elements
Authors: Akhmedov Sherzod , Saatova Nodira , Radjabov Tokhir , Shojalilov Shukhrat , Safarov Shakhzod
Published: August 2023

The article presents the results of studies of the mechanism of force transfer through cracks in reinforced concrete elements. New results for estimating the ultimate shear resistance and stiffness of sections with cracks are reflected. Tests of prototypes of the were carried out in a hydraulic press. To install the test sample into the press, without changing the value of the initial crack width obtained as a result of splitting, a special rigid frame made of metal corners was made during the sample turning.
CFD-mass transfer model process in a vertical sedimentation tank
Authors: Rizayev A. N. , Adilov K. A. , Xushvaqtov D. Q. , Ergashev Q. X.
Published: August 2023

Currently, the world is actively developing a logical course to create hypothetical strategies for the calculation of tanks for sewage sump. At the same time, engineers usually use balance models and one-dimensional kinematic models. These models do not take into account the hydrodynamics of the flow inside the sump and its complex geometric shape. This can be a serious deterrent to the widespread use of Navier-Stokes conditions when refining a regular plan. The use of CFD models based on the formulation of Navier-Stokes conditions requires the use of a really thin network, which leads to critical computer time spent on obtaining predictive information. To this conclusion, it is fundamental to form an successful CFD show to think about the method of wastewater treatment in vertical settling tanks, taking into consideration their geometric shape and plan highlights. The plans of individual parts, carried out by the strategy of the current count, are used. A 2-D-CFD demo was created that allows a vertical settler to be calculated in a few seconds, taking into account its geometric shape, the proximity of the central pipe, its parameters, and the proximity of a divider that has recently exited the pipe. The application of the strategy for checking the calculated space in the constructed show makes it possible to carry out coordinate numerical simulation of the flow hydrodynamics and mass transfer in settling tanks without limiting their shape. Creation of CFD models that allow, on the one hand, to require into consideration the geometric shape of the sump, the most physical forms of mass exchange within the structure, and on the other hand - requiring small time to get comes about. The created CFD demonstrate and the code based on it permit, with a little consumption of computer time - approximately the same as when calculating a one-dimensional demonstrate, to illuminate complex multiparametric issues that emerge at the plan arrange of vertical settling tanks, considering their shape and design features.
Study of the motion of modified solid particles in hydratransport systems
Authors: Chorshanbiev Umar , Ibadullaev Ahmadjon , Babaev Asqar , Kaxarov Baxadir
Published: August 2023

The article examines the movement of solid particles, the hydraulic calculations of pipes in the process of movement, the classification of reducing the impact of solid particles on hydrotransport systems. The effect of solid particle magnification on flow rate, pressure loss, speed reduction as a result of the effect of internal friction forces of solid particles, friction in the flow of solid particle hydroarations, pressure loss as a result of the impact of Resistance Forces, internal corrosion process observed in the pipe, increased energy consumption were analyzed using the example of hydrotransport systems Recommendations have been made to solve the problems of speed reduction and pressure loss due to the movement of solid particles in the hydroaration flow through the modification method. The prior and subsequent movement of solid particles in a pipe modification is shown through comparison graphs. Information about the gossipol Tar selected as a modifier is provided.