bluuebunny/crossref_metadata_2025 huggingface dataset:
Method for determining optimal overhaul service of centrifugal and axial pumps
Authors: Uralov Bakhtiyor , Eshev Sobir , Khakimova G. , Mutalov Sh. , Raimova I. , Arzieva D. , Salimbayev Mirsoxibjon
Published: August 2023

The efficiency of pump operation mainly depends on the maximum permissible wear of the parts of their flow path. One of the factors determining the need for repair and restoration of centrifugal and axial pumps is the wear of parts that form the sealing and slotted gaps of the impellers. With an increase in the design clearances of the impellers, the leakage of liquid increases proportionally, and this worsens the energy performance of the pumps and, accordingly, leads to an increase in operating costs. At certain clearance values, the costs reach such a value that the pump operation becomes impractical. Therefore, when assessing the pump's performance, it is important to establish the wear limits of its parts. About a machine part, the limit state is a state in which its further operation is impossible due to an unrecoverable decrease in operating efficiency below the permissible level or the need for repair.
New concept of cast iron melting technology in induction crucible furnace
Authors: Turakulov Murot , Tursunov Nodirjon , Yunusov Salokhiddin
Published: August 2023

The article considers methods for reducing harmful impurities in the composition of synthetic cast iron (SCI) and improving the strength characteristics of cast iron. A new method for smelting SCI using steel scrap as charge materials in induction crucible furnaces is proposed, including filling of metal charge, together with transfer cast iron, return of own production, carburetors, and ferroalloys to carburize and alloy up to the required chemical composition. It is revealed that with an increase in steel scrap in the metal charge, the melting time, specific power consumption, melting duration, hardness of the experimental sample increase, and the yield of usable liquid cast iron decreases. To achieve the required hardness of the experimental sample, it is necessary to have мeтaллoшихтefrom 10 to 40% of steel scrap in the metal charge.
Strength of reinforced concrete T-beams of bridges reinforced with external reinforcement from fabric polymeric composites
Authors: Akhmedov Sherzod , Aripov Khodjiakmal , Ospanov Ruslan , Mirzaolimov Ilhom , Kenjayev Temurbek
Published: August 2023

Work is devoted to rehabilitating damaged, injured reinforced concrete T-beams of bridges of carbon fibre-reinforced plastic materials. Estimating beams' resistance at shear depended on the percent of longitudinal working reinforcing- μ, attitudes of flight of shear to a working height of section - av/ho, an interval, quantity, and orientation of CFFM strips. The mechanism of destruction and estimation of bearing ability strengthened damaged and intact Т-beams are investigated at shear. Results of deformations of the stretched working and cross-section armature, deformations of concrete on the height of beams and in strips CFFM from loading. The influence of CFFM on the bearing ability and character of the destruction of beams is investigated.
Traffic intensity on roads with big longitudinal slope in mountain conditions
Authors: Fayzullayev Erkin , Khakimov Shaukat , Rakhmonov Azimjon , Rajapova Sayyora , Rakhimbaev Zokhidjon
Published: August 2023

The instantaneous, average, and critical speeds of vehicles passing through the Kamchik pass were determined in this article. The law of critical speeds of safe movement of the traffic flow has been developed. The research results on determining the speed of movement of vehicles of different categories in mountain conditions are presented. To ensure safety, depending on the speed of the vehicles and the condition of the road surface on the dangerous areas of the mountain road, recommendations are given on the speed limits and road signs to be installed.
Influence of type of modified fillers based on dune sand on properties of cement paste, stone, and on technological and strength properties of concrete
Authors: Narov Rustam , Rashidov Jasur , Turgunbayev Urinbek
Published: August 2023

Industrial enterprises are being built on a large scale in the desert regions of Uzbekistan. Concrete remains the main material in construction to this day. However, there is an acute shortage of sand of normal size. In this regard, an urgent task is to find effective and affordable technological methods for improving the properties of cement paste, concrete mix, and concrete on dune sand and cement savings. Taking into account our previous studies, the main attention was paid to establishing quantitative dependencies, changing the properties of cement paste and concrete from the introduction of sand dune fillers modified with additives of acidic (SDFMAA) and basic (marl) nature into their composition and the influence of methods for preparing a mixture of conventional and separate.
Rayleigh and love surface waves with regard to seismic stress state of earth bed
Authors: Shayakhmetov S. B. , Kalpenova Z. D. , Lesov K. S. , Umarov Kh. K.
Published: August 2023

This article presents the results of studies on the propagation of surface seismic waves, which directly affect the stability and strength of a high embankment of the subgrade. The subgrade is the foundation of the railway track. In an elastic half-space with a layer in which surface waves propagate, the conditions for the existence and propagation of a harmonic Rayleigh wave are considered. The equations of motion of a medium in a layer and half-space and their solutions in the form of plane waves propagating in phase along the contact boundary, some general laws of Rayleigh wave propagation are given. The accepted theories and calculation methods' main provisions are proposed for designing a durable and reliable subgrade and considering its seismic stress state.
Influence temperature and strong magnetic field on oscillations of density of energy states in heterostructures with quantum wells Hgcdte/Cdhgte
Authors: Erkaboev U. I. , Sayidov N. A. , Negmatov U. M. , Mirzaev J. I. , Rakhimov R. G.
Published: August 2023

For the first time, the influence of temperature and a transverse strong magnetic field on the oscillations of the density of energy states is studied in the conduction band of heterostructures with quantum wells HgCdTe/CdHgTe. Analytical expressions are derived for oscillations of the density of states in quantum-dimensional heterostructural materials in the presence of transverse quantizing magnetic fields with a parabolic dispersion law. A new mathematical model has been developed for calculating the temperature dependence of the density of states oscillations in nanosized heterostructural materials under the action of a transverse quantizing magnetic field.
Assessment of land reclamation status using remote sensing and GIS in territory of Pakhtakor district of Uzbekistan
Authors: Mukhtorov Uzbekkhon , Gapparov Samandar , Djumaev Ziyadulla , Utaev Abdukholik , Olloniyozov Sardor , Karimov Erkin
Published: August 2023

The importance of land distribution across all sectors of the national economy cannot be overstated, particularly in agriculture. Agricultural land plays a critical role in meeting the population's food needs and satisfying the demand for raw materials in the industry. The fertility of the land is the main productive property in agriculture. Continuous improvements in land productivity, combined with the adoption of innovative technologies, are key factors in modern agriculture development. However, natural and anthropogenic factors are negatively impacting agricultural land productivity, leading to a decrease in productivity. To prevent this, urgent measures must be taken to improve the reclamation conditions of agricultural lands, develop regions following climate change, and effectively organize cadastral reclamation activities. Additionally, monitoring the reclamation condition of agricultural lands is crucial in times of scarcity. This research focuses on the assessment of the melioration condition of agricultural land in the Pakhtakor district of the Republic of Uzbekistan, using geoinformation technologies and remote sensing data. These technologies enable the low-cost, timely, and high-accuracy measurement of changes in soil conditions over large land areas. By continuously monitoring the earth's surface, we can identify existing problems and develop timely solutions to address them. In research, enhancing agricultural land productivity is a critical task for modern agriculture development. Innovative technologies and effective monitoring strategies, such as geoinformation and remote sensing techniques, are essential to achieving this goal. Through this research, we hope to contribute to the continued improvement of land management practices and sustainable agriculture in Uzbekistan.
Criteria for integro-differential modeling of plane-parallel flow of viscous incompressible fluid
Authors: Abdullaev A. A. , Safarbayeva N. M. , Kholkhodjaev B.
Published: August 2023

For a liquid with a nonmonotonic flow curve in the stationary case in the region of the descending branch, setting the velocity at the boundary does not uniquely determine the shear stress, strain rate distribution, and velocity profile that arise since the problem is known to have many unstable solutions. At the same time, the problem of the motion of such fluid under the action of a given pressure difference has no more than three solutions, two of which are stable, and the third is unstable and not reproducible. Which of the two stable solutions is realized depends on the loading history. The problem of determining the velocity profile for a fluid characterized by a nonmonotonic rheological flow curve between parallel planes is considered. The existence of a solution is realized by reducing the problem posed to a singular integral equation of normal type, which is known by the Carleman – Vekua regularization method developed by S.G. Mikhlin and M.M. Smirnov equivalently reduces to the Fredholm integral equation of the second kind, and the solvability of the latter follows from the uniqueness of the solution delivered problem describing of criteria for integro–differential modeling of a plane-parallel flow of a viscous incompressible fluid.
Calorimetric study of methanol adsorption in LiZSM-5 and CsZSM-5 zeolites
Authors: Ergashev Oybek , Bakhronov Khayot , Akhmedova Nodira , Abdullayeva Shoira , Khalilov Sarvar , Kholikov Kamoliddin
Published: August 2023

This paper presents isotherms and basic (ΔH, ΔF,and ΔS) thermodynamic characteristics of methanol adsorption in Li3,37ZSM-5 and Cs3,17ZSM-5 zeolites obtained by the calorimetric method. For measurements of isotherms and differential heat of adsorption, a system consisting of a universal high-vacuum adsorption unit and an attached differential modified Tian-Calvet type microcalorimeter, DAC-1-1A, which directly quantifies and qualifies the nature and forces of adsorption interaction, was used. The adsorption isotherm is described by the equations of the volumetric micropore filling theory (VMOT). The correlation between the adsorption-energy characteristics is found, and the molecular mechanism of methanol adsorption in Li3,37ZSM-5 and Cs3,17ZSM-5 zeolites throughout the filling region is revealed. Methanol adsorbed in Li3,37ZSM-5 and Cs3,17ZSM-5 zeolites is located in the first coordination sphere with cations Li+and Cs+, forming tetra- and trimeric complexes. It is found that the charge density significantly affects the adsorption mechanism, the adsorption energy, and the number of adsorbed molecules. It was determined that the average molar entropy of ammonia adsorption on LiZSM-5 and CsZSM-5 zeolites indicates that the mobility of methanol molecules in the zeolite is below the liquid phase and close to the mobility of the solid phase, indicating a strong inhibition of mobility of methanol adsorbed on cations. This work shows how calorimetric data can complement crystal structure results and detect subtle adsorbent/adsorbate interactions at the molecular level.
Basic thermodynamic characteristics and isotherm of ammonia adsorption in NaZSM-5 and LiZSM-5 zeolites
Authors: Bakhronov Khayot , Ergashev Oybek , Sultonov Amirkhon , Kholmedov Hamid , Ganiev Abror , Asfandiyorov Maruf
Published: August 2023

This paper presents the results of isotherm and basic (ΔH, ΔF,and ΔS) thermodynamic characteristics of ammonia adsorption in Na zeolites2,87ZSM-5 and Li3,37ZSM-5; also the adsorption isotherm is described by the bulk micro-pore filling theory (BFM) equations. The correlation between adsorption-energy characteristics is found, and the molecular mechanism of ammonia adsorption in Na2,87ZSM-5 and Li3,37ZSM-5 zeolites in the whole filling region is revealed. The ammonia adsorbed in NaZSM-5 and LiZSM-5 zeolites is located in the first coordination sphere with Na+and Li+cations, forming octa- and hexaammonia complexes. From the adsorption thermokinetics, it was determined that Li+cations are located in the screened positions of the ZSM-5 zeolite crystal lattice. The adsorption of ammonia molecule results in Li+cations migration from the zeolite lattice into junctions formed by the intersection of straight and zigzag channels and the formation of ion/molecular complexes of various multiplicity in them. It was determined that the average molar entropy of ammonia adsorption on NaZSM-5 and LiZSM-5 zeolites indicates that the mobility of ammonia molecules in the zeolite is below the liquid phase and close to the mobility of the solid phase, indicating a strong limitation of mobility of ammonia adsorbed on the cations.
Mathematical model of braking process of car
Authors: Kasimov Omil , Tukhtamishov Sobit
Published: August 2023

A mathematical model of braking a car using differential equations has been compiled. The calculation scheme of the plane-parallel motion of the car during braking is given. When braking a car, three forces are considered in the contact of each wheel with the road: the braking force, the slip resistance force, and the normal reaction of the road. A diagram of the components of the braking force acting in the plane contact of the wheel with the road when sliding. A scheme has been drawn up to determine the normal reactions on the wheels of a car. To assess the preservation of the car's controllability, a function of the driver's control action is introduced into the mathematical model, imitating the algorithm of his action. The angular speed of the steering wheel is limited by the driver's capabilities, and in emergencies is 250 ... 350 deg / s. If the heading angle decreased with the introduction of the driver's control action function, then the skid was considered controlled.
Determination of state of avalanche protection gallery during seismic impact and avalanches
Authors: Abdujabarov Abdukhamit , Begmatov Pardaboy , Eshonov Farkhod , Mekhmonov Mashkhurbek , Khamidov Maqsudjon
Published: August 2023

The article considers the definitions of the state of the avalanche protection gallery under seismic impact and avalanches. Determined emerging horizontal and vertical vibrations of the entire structure. A calculation scheme was developed to study the dynamics of loose bodies. The scheme of vibrations of a reinforced concrete gallery with an arch covering with backfill soil during a possible earthquake in the OYZ plane is considered. The main type of vibration is lateral, vertical dynamic forces in the ground backfill. The dependence of horizontal forces on the snow layer, the dependence of the force Fr on the gallery on the speed of avalanche movement, the dependence of the force Fr on the unevenness of the backfill soil, and the change in the frequency characteristics of the gallery on the speed of avalanche movement were determined.
Results of theoretical and experimental data of tractor cabin carcass
Authors: Khakimzyanov R. R.
Published: August 2023

In the article results of the comparative analysis of the elastic-plastic calculation of a protective skeleton of a cabin of a tractor based on a method of final elements with the experimental research spent on the cabin of the tractor of class 1.4.are resulted. The carried out research has shown good adequacy of the received theoretical results (the maximum deviation does not exceed 12 %, and an average deviation of 8 %), and the offered technique of elastic-plastic calculation can be applied by working out new designs of a skeleton of cabins of tractors.
Research on methods for effective use of machines in kit in construction and repair of asphalt concrete pavement
Authors: Maksudov Zakir , Kudaybergenov Mavlyan
Published: August 2023

This paper develops a methodology for studying the effective use of asphalt paving and transport machines, the main determining parameters of which are the cost and productivity of transporting and laying asphalt concrete mix. An algorithm has been developed for optimizing the operational performance of a set of asphalt paving and transport machines in the construction and repair of roads.
Modeling of cargo flow processes in the logistics of the transport system
Authors: Usmonov Jonibek , Djuraev Tulkindjon , Malikova Nodira , Kuvnakov Avaz
Published: August 2023

The management of cargo flows and transport activities is one of the most significant challenges currently. This article aims to discuss optimizing material flows in both transport and cargo management. It also develops mathematical software and material flow structures to facilitate management and production functions in supply enterprises. The article solves regulatory and forecasting issues using material flows and information models to optimize vehicle operational forms.
Structure of refractory materials based on local mineral raw
Authors: Rashidov Jasur , Ibragimov Bakhrom , Chulliyev Farkhod , Salimova Iroda
Published: August 2023

The paper is devoted to the results of microscopic analysis of the structure of fire-resistant materials developed on the basis of local mineral raw materials. The authors point out that in this regard, a special place is occupied by the microscopic analysis of refractory materials, because the use of various radiation and various designs of microscopes from optical to electronic requires various special preparation of objects and special methods for deciphering the observed images. Moreover, the use of these methods in relation to the fire-resistant compositions obtained during the experiments, consisting of kaolin, wollastonite, soda water glass, silica, finely dispersed thermovermiculite, silicon dioxide, dolomite, etc., demonstrates their microrelief morphology, which gives rise to other experiments related to increasing the quality of fire resistance of the objects under study.
Capacity Utilization Factor (CUF) of the 70kW on-grid solar station in the dry climate of Termez
Authors: Tursunov M. N. , Sabirov Kh. , Axtamov T. Z. , Abdiyev U. B. , Chariyev M. M. , Yuldoshov B. A. , Toshpulatov S. F.
Published: August 2023

The aim of the present study was to assess the installed capacity utilization factor and the suitability of a 70kW photovoltaic plant placed on the roof of a dormitory located at Termez city (Termez state university). We can report the energy to production directly through mobile devices. CUF is one of the quantities that shows the performance quality of each power generating station. The results of our research cover two months autumn and winter. Through this, the theoretically estimated minimum values of CUF on the least sunny days have also been proven in real values. It is estimated that the annual result of this value will be around 15%-20%. Because in the winter months, the value of individual CUF on open days increases by 20%. An estimated 15.68 mln kg of CO2 was avoided due to the generation of 22.4MWh of energy. This is a small improvement in the environment and energy sector.
Device for measuring the magnetic scattering field of the frontal part of the stator winding of a traction asynchronous electric motor of an electric rolling stock
Authors: Pirmatov N. B. , Berdiyev U. T. , Usmonov K. K. , Nazirkhanov T. M. , Berdiyorov U. N.
Published: August 2023

The article deals with the issues of improving the energy efficiency of mainline locomotives with asynchronous traction motors by determining the characteristics of the traction drive using a device for measuring the magnetic scattering field of the frontal part of the stator winding.
Parameters of the access road for disaster situations on the roads in the mountain area
Authors: Faizullaev E. Z. , Rakhmonov A. S. , Mukhtorjanov U. M. , Turdibekov S. , Nasirjanov Sh. I.
Published: August 2023

In the article, a mathematical model for determining the parameters of the access road for catastrophic situations on highways passing through the mountainous area is developed. The reliability of the mathematical model is proven by experiment.
Study of a protein-containing and keto-dietary product based on local raw materials
Authors: Atakhodjaeva Inoyat , Akramova Rano , Choriyev Abdusattor , To‘xtayev Shuxrat , Li Vyacheslav
Published: August 2023

An urgent task of our era is the development of such compositions of innovative multifunctional products that take into account the effect of mutual enrichment of products of animal and vegetable origin, physiological substances, the ability of dietary fiber to remove harmful substances from the body and the ability of prebiotics to maintain microecological balance in the gastrointestinal tract.
Manufacturing technology of photovoltaic devices based on layered compositions and their properties
Authors: Umarov A. V. , Djumabayev D. K. , Mirsalikhov B. A. , Kasimova G. A.
Published: August 2023

The paper considers the manufacturing technology and study of the mechanisms of operation and properties of layered electrical compositions, as well as the study of the possibility of obtaining effective photoelectric converters on their basis.
Forecasting potato yield dynamics in the Tashkent region of the Republic of Uzbekistan
Authors: Vakhabov V. V. , Hidoyatova M. A.
Published: August 2023

Observations of some phenomenon, the nature of which changes over time, generates an ordered sequence, which is called a time series. The statistical regularity of the series of dynamics ȳt the average potato yield in the Tashkent region of the Republic of Uzbekistan (based on the materials of the CSO of the Republic of Uzbekistan for 2000-2018 year) was studied by the method of statistical analysis of time series. Point and interval estimates for the average potato yield were built with a 95% guarantee, explicit types of trends were identified and the yield in the Tashkent region was predicted for subsequent years. Using the Darbin-Watson statistical criteria, it was found that the average potato yield in the region has autocorrelation dependence.
Field studies to determine the deformations of low-pressure hydraulic structures
Authors: Paluanov Daniyar
Published: August 2023

The article deals with the issues of field studies of the deformation of low-pressure hydraulic structures in operation. Based on the results of the project, preliminary and repeated geodetic measurements, a longitudinal profile of sedimentation of the concrete structure body was built using the obtained leveling.
Factors affecting electrolytic level maintenance in acid batteries
Authors: Mamatkulov Asilbek , Erkabaev Furkat
Published: August 2023

The aim of this study is to increase the utilization factor of the active masses by ensuring that the electrolyte in the batteries is evenly distributed over the separator height and kept constant at the desired height.
Media resources in video information systems
Authors: Beknazarova Saida , Ishanxadjayeva Zamira , Jaumitbaeva Mexriban
Published: August 2023

The article describes methods for increasing the contrast of images in video information systems, the main compression of the video stream is provided by eliminating inter-frame redundancy using methods for compensating the movement of image fragments of adjacent frames. However, the use of motion compensation methods requires the formation of additional data (metadata) containing information about the types of image blocks used, their movement coordinates, etc. At the same time, in order to increase the compression of the video stream without sacrificing its quality, a higher accuracy of motion compensation is required, which leads to an increase in the number of blocks and, accordingly, an increase in the volume of the video stream metadata that reduces the effectiveness of motion compensation. This is the main problem of compressing streaming video without compromising image quality. In addition, higher positioning accuracy of blocks with motion compensation dramatically reduces the speed of image processing, which is not always feasible in real-time systems.
Technology of fabrication of CDSXTe1-X solid solution on silicon substrate
Authors: Sapaev I. B. , Sapaev B. , Babajanov D.
Published: August 2023

Heterojunction between Si and CdSxTe1-x have been obtained by vacuum deposition of powders of cadmium sulfide and cadmium telluride on the surface of monocrystalline silicon. The optimal temperature regime for the growth of the CdSxTe1-x solid solution on the silicon surface has been determined. The values of the crystal lattice constant and the thickness of the CdSxTe1-x solid solution at the interface of the n/Si − n/ CdSxTe1-x heterostructure are calculated.
Methods for improving contrast of agricultural images
Authors: Mamatov N. S. , Niyozmatova N. A. , Jalelova M. M. , Samijonov A. N. , Tojiboyeva Sh. X.
Published: August 2023

In recent years, there has been a sharp increase in interest in using satellite imagery in agriculture. These images are useful for monitoring crops, analyzing soil conditions, and identifying potential machine problems. However, the quality of these images can vary greatly depending on factors such as weather conditions, time of day, and the type of satellite used. One common problem with images, in general, is poor contrast or lack of contrast, which can make it difficult to identify objects such as crops or machinery. This work is devoted to methods of contrast enhancement and evaluation criteria used to improve the quality of agricultural images obtained from satellites and unmanned aerial vehicles, as well as the selection of the optimal pair of criteria and methods.
Method of calculation of the magnetic induction of the stator winding of a spiritual synchronous motor
Authors: Toirov O. , Pirmatov N. , Khalbutaeva A. , Jumaeva D. , Khamzaev A.
Published: August 2023

This article discusses the calculation of the magnetic fields of the differential scattering of the stator, passing in the radial direction (penetrating the body of the rotor core), taking into account the saturation nonlinearities of the tooth zones of the magnetic circuit. The results of the method for calculating the magnetic permeability of the final values of the steel sections of the magnetic circuit in the stator and rotor of a salient-pole synchronous motor for its spatial harmonic fields in the air gap are presented.
Modeling of vertical axis wind turbine using Ansys Fluent package program
Authors: Khujaev Ismatulla , Toirov Olimjon , Jumayev Jura , Hamdamov Muzaffar
Published: August 2023

The paper considers a variant of the problem of modeling the flow around a developed wind turbine. Building a CAD model Fig. 1. was carried out in the SolidWorks environment, where the main geometric dimensions were specified. Since the task is reduced to modeling a flat task, the 2D design mode was chosen.
Study of possibilities of getting nanocarbons from butadien-1.3 and texture characteristics of nanocarbons and catalyses
Authors: Djanikulov Sherali , Fayzullayev Normurot
Published: August 2023

The purpose of the study is to study the possibility of obtaining nanocarbons in a catalyst containing 15%Ni*5%Co*5%Fe*5%Cu*2% Mo/HSZ and to check the texture characteristics of the catalyst and nanocarbon. The research method is a catalyst containing 15%Ni*5%Co*5%Fe*5%Cu*2%Mo/HSZ prepared by precipitation of nitrates of the corresponding metals. The method of examination is electron microscopy. The morphological composition of the samples was performed by scanning electron microscopy (SEM) on a device "JEOL JSM-6390 LA" equipped with an energy dispersion X-ray microanalysis unit (EDX). We place the sample on double-sided carbon conductive tape glued to a copper-chrome table. Then we vacuum it in the instrument chamber. Microphotography recording was performed at 5-25 kV working distances and 8-10 mm under accelerating voltage. EDX spectra were recorded at 20 kV, with a working distance of 10 mm. The microstructure of the samples was examined by scanning electron microscopy. The JEOL 2100F used an accelerating voltage of 200 kV. The samples were dispersed, processed in ultrasound with methanol, and rubbed on a copper wall. The catalysts were preheated and passivated at 400 ℃ for 4 h at a 30 ml/min flow of nitrogen. Recycled catalysts are also 2% by volume in an oxygen-argon mixture. The O2/Ar reaction was inactivated at room temperature after cessation. The average size of the metal particles and the diameter of the carbon nanotubes were determined in the Image-ProPlus program. We calculated the average size of 500 particles for each catalyst, and 100 carbon nanotubes were processed to measure the average diameter of the carbon nanotubes. After synthesis and functionalization of carriers in the catalyst 15%Ni*5%Co*5%Fe*5%Cu*2%Mo/HSZ, the nanocarbons were condensed, and their outer diameter remained unchanged and amounted to 10-30 nm. Carbon nanotubes range in diameter from 5 to 15 nm, depending on the size of the metal particles, and in length from a few microns. The main conclusions are that the highly dispersed metal particles located at the ends of the nanotubes are an important factor in the growth of nanotubes. Larger iron particles are characterized by changes in the diameter of carbon nanotubes during growth. At the beginning of growth, the diameter of such a nanotube is 30...50 nm; however, it decreases to 5...15 nm.
Human body temperature monitoring wireless system
Authors: Zakirov Ruslan , Abdulhaev Oybek , Khakimov Alim , Rahmatov Ahmad , Yodgorova Dilbara , Kuliev Shukur , Istamov Damir
Published: August 2023

To solve the problems of medical diagnostics, human body temperature measurement has become widespread. In many cases, to make a correct diagnosis, it is required to obtain results of continuous monitoring during a certain period instead of a single temperature measurement. This paper discusses a wireless body temperature monitoring system using a high-precision semiconductor sensor and the RN 4870 Bluetooth module.
Steeling of synthetic cast iron in induction crucible furnace taking into account consumption rate of carburizers
Authors: Turakulov Murot , Tursunov Nodirjon , Yunusov Salokhiddin
Published: August 2023

In an article about the importance of the choice of materilas, harmful impurities in synthetic cast iron, amd improving the strength characteristics of cast iron, which requires a new method of smelting synthetic cast iron using steel scrap as charge in the corrresponding crucible furnaces, the presences of a charge of metal charge, together with pig iron, the return of own production, carburetors, and ferroalloys for the purpose of carburizing and alloying to the required chemical composition.
Arrangement of equipment at production site of multi-product production using heuristic algorithm
Authors: Abdukarimov T. G. , Erkinov Sh. N. , Nasullayeva M. Q. , Aliyev J. V. , O’lmasov S. Kh.
Published: August 2023

This article considers the task finding of the optimum equipment arrangement on the production site. Naturally, even earlier, before the development of the concept of lean manufacturing, the designers of machine-building enterprises faced the task of minimizing transportation costs. However, the techniques used in the past are usually focused on mass production, not lean, and therefore cannot be correctly used in the design of modern production systems. In addition, such methods, often developed several decades ago, are based on a broad regulatory framework and accumulated experience in designing enterprises. Still, they are not designed to use computer technology to find solutions to optimization problems typical for production design. As a result, today, the task of creating methods for designing enterprises, taking into account the specifics of lean production and involving the use of computers to solve optimization problems of designing machine-building production, is relevant. Flexible and rigid settlement models of the solution of a task are described, and the shortcomings and advantages of both models are specified. The algorithm of the solution of a task when using a flexible model is offered. This algorithm is constructed on a synthesis of a heuristic algorithm of imitation of annealing with linear programming methods.
Study of the friction of the brake shoe of a freight car
Authors: Inagamov Sardor , Djabbarov Shukhrat , Abdullaev Bakhrom , Ruzmetov Yadgor , Inoyatov Kamoliddin , Hurmatov Yahyo
Published: August 2023

This article explores issues related to the friction of the brake pads of a freight car. The coefficients of friction of composite and cast-iron pads of a new type, calculated for a range of different speeds, and the specific braking force during emergency braking are given. A sectional brake block for a freight car and a locomotive has been developed. The advantages of sectional brake pads have been scientifically substantiated. The obtained calculations allow us to recommend them for further study and implementation in operation on the railways.
Study of the physico-chemical characteristics of reinforced composite polymer materials
Authors: Khalimov Shukhrat , Nishonov Farkhodkhon , Begmatov Dilmurod , Wani Mohammad Farooq , Ziyamukhamedova Umida
Published: August 2023

One of the important properties of reinforced composite polymer materials is their physico-chemical properties. Their structure plays an important role in assessing the physico-chemical properties of composite materials. Research objectives - to study the physico-chemical properties of high-strength polymer composite materials.

Experiments were carried out at 100 and 400-fold magnification in an optical microscope to study the morphology and structural changes of various parts of high-strength polymer composite materials with a polymer binder - ED-20 and nitrone fibers. IR spectroscopic studies were also carried out to study the interaction of nitron fibers with an epoxy binder - ED-20 during the formation of high-strength polymer composite materials. The data obtained in the study of various sections of polymer composites revealed a linear structure characteristic of nitron fibers coated on all sides with a polymer binder - ED-20, and structural changes in morphology at 100 and 400-fold magnification. Infrared spectral studies showed that the intermolecular interaction between hydroxyl and amide groups was established as a result of the interaction of the nitrile groups of the nitrone fiber and ED-20 with PEPA. Based on the analysis of the results obtained, it can be concluded that the developed composite materials based on epoxy binders with nitrone fibers can be considered as a new class of composite materials designed to operate under high stress conditions.
Limited different schemes for mutual diffusion problems
Authors: Muhamediyeva D. K. , Muminov S. , Shaazizova M. E. , Hidirova Ch. , Bahromova Yu.
Published: August 2023

In the article, the problems of mutual diffusion, represented by a system of nonlinear differential equations of parabolic type, were modeled following numerical solving methods. The developed software was tested using various examples and obtained positive results. Mutual diffusion processes were visualized.
Practice of applying models of clustering of incoming semi-structured data in management systems
Authors: Askaraliyev O. U. , Muxtarova G. X. , Malikova N. T. , Yuldashev R. H.
Published: August 2023

A scheme for solving the problem of binary clustering of incoming data in the control system is proposed. Different ways of presenting the initial data of the clustering problem are considered. Methods of sequential shortening and sequential merging of clusters and the model of initial placement of clusters are considered. Estimating the number of clusters is given to solve the clustering problem. A binary clustering method has been proposed for points in a circle. The clustering practice was performed based on the research results, and the developed model and algorithms were implemented. The optimal variant of the processing process based on clustering methods for semi-formed information sources is proposed based on the proposed structure.
Development of models and algorithms of aerodynamic drag of a high-speed train and calculations of particle entrainment
Authors: Ravshanov N. , Egamberdiev B. B.
Published: August 2023

The work is a study of the patterns of jet-cavitation air flows when flowing around a high-speed passenger train. On the basis of theoretical studies, the forces of resistance (frontal and near-wall) of the external environment to the movement of the train, the influence of cavitation currents on the near-wall layer, the current flows generated during the movement of the rolling stock, the resistance of the external environment of the rolling stock, both as a whole and on each car of the train, are determined, the influence of cavitation flow from solid particles lying on the underlying surface, critical velocities that reduce the entrainment of solid particles, establishing the regularity of the movement of entrained solid particles. The work also includes a theoretical determination of the aerodynamic drag coefficient and hydrodynamic pressure forces, normal and shear stresses on the surface of the wall of a train consisting of n cars, a study of the effect of gaps between cars and on the speed characteristics of the train, leading to a change in the acceleration of cars.
New composition of chemicals and heavy drilling fluids for drilling oil and gas wells
Authors: Kobilov Nodirbek , Khamidov Bosit , Shukurov Abror , Kodirov Sarvar , Juraev Kuvonchbek
Published: August 2023

The article shows the importance of obtaining new composition of heavy drilling fluids based on composite chemical reagents from local raw materials and industrial wastes for drilling oil and gas wells. In the process of building oil and gas wells to maintain the stability of the walls, to prevent the flow of salts, and to prevent the penetration of formation fluids into the well, it becomes necessary to increase the density of the drilling fluid, which can be accomplished by introducing components with increased density. For obtaining and stabilization heavy drilling fluid were investigated and recommended new compositions of powder water soluble gossypol resin and carboxymetylcellylose sodium and other minerals. Stabilization indexes and their determination in the drilling process of oil and gas wells have been investigated. The result of research have been implemented in the drilling process of oil and gas wells with abnormally high reservoir pressure.
Development and research of layered composite materials based on Cu2ZnSnS(Se)4 for solar cells
Authors: Umarov A. V. , Mirsalixov B. A. , Djumabayev D. K. , Xusnuddinov F. X.
Published: August 2023

This paper discusses the development of manufacturing technology with low costs for the production of solar cells based on Cu2ZnSnS(Se)4 crystals, elucidation of the physical principles of operation and the search for solutions to improve the efficiency of converting solar energy into electrical energy. The morphology of grown ingots and some electrophysical properties of Cu2ZnSnS(Se)4 crystals were studied.
Urban space digitalisation as a factor in urban communities’ consolidation
Authors: Babintsev V.P. , Khripkova D.V. , Khripkov K.A.
Published: August 2023

The article is devoted to the study of the impact of digitalisation of the provincial Russian cities on the prospects of consolidation of urban communities. It is noted that digitalisation qualitatively change the metabolism of the modern city, turning the urban environment into a space of interaction of complex socio-biotechnical systems. Virtual-digital practises, technologies, and services are built into all the processes of urban development, which leads to the transformation of most social phenomena: processes, institutions, communities, as it makes society more dynamic, changeable, “turbulent”. Based on the results of the expert survey, which was conducted in the sociological study Social Consolidation of Urban Communities - Opportunities and Limitations in a Digitalized Urban Environment, March-April 2022 (N = 50), the positive and negative effects of digitalisation / digitalisation of the urban environment for the prospects of social consolidation are analyzed. It is empirically confirmed that the wiggle effects of the digitalisation of the urban environment on the enhancement of consolidation are ambivalent. On the one hand, digitalisation creates new conditions for communication and mobilisation of city dwellers, but on the other hand, it leads to the emergence of nontraditional barriers.
Functional zoning in urban planning and architectural design
Authors: Stetsky S.V. , Zheltaya A.O. , Dorozhkina E.A.
Published: August 2023

The article discusses a variety of issues, concerning functional zoning. These questions are being considered, starting from the wide-scale urban territories and up to small private plots and dwellings. The urban planning and design are being analyzed in accordance to the main classification features, i.e., in accordance to the number of population, planning schemes and planning structures. It is noted, that in the long run, the principles of zoning are highly dependent in the above-mentioned points of a master planning. The functional zoning of individual houses or flats are being considered with nearly the same method adopted. A dwelling division to functional zones depends upon its size, number of occupants, personal desires, etc.
Contribution of E-Leadership to 21st-Century Competencies of Principals in Riau Province
Authors: Ayub Daeng , Adi Putra M. Jaya , Muryanti Muryanti
Published: August 2023

The main objective of this study was to examine the contribution of e-leadership, specifically among principals in Elementary Schools, Junior High Schools, Senior High Schools, and Vocational High Schools. The study population consisted of 384 participants, with a sample size of 196 principals. A quantitative approach was used, employing two variables. Data was collected through a questionnaire and analysed using descriptive and inferential statistical analysis. The results of the study indicated that the mean score for Principals’ 21st-century Competencies was 3.76, falling into the highest category. Similarly, the mean score for the Variable E-Leadership among principals was 3.77, also falling into the highest category. The study revealed that e-leadership accounted for 69.80% of the contribution to the principals’ 21st-century Competencies, with the remaining 30.20% being attributed to other factors. It is important to note that principals who demonstrate effective leadership utilizing technological advancements in the 21st-century are more likely to possess good 21st-century competencies. The findings also highlight that higher levels of e-leadership correspond to greater competency among principals in the 21st-century. Therefore, it is recommended that principals enhance their e-leadership capabilities to further develop their 21st-century competencies.
Needs Analysis for Developing Problem Solving-Based E-Module for Projectile Motion to Train High School Students’ Conceptual Understanding in Pekanbaru
Authors: Azizahwati Azizahwati , Purwaningsih Sri , Sahal Muhammad , Harlipadensi Harlipadensi , Rahmad M.
Published: August 2023

The conceptual understanding of high school students in Pekanbaru is still low. This is due to: 1) the need for students’ active involvement in problem-solving activities and 2) the lack of interactive learning resources in motivating and strengthening students’ conceptual understanding. Students’ low conceptual understanding can be overcome by using a learning media in the form of a problem-solving-based e-module in the learning activities. This research is survey research—the first step in developing a problem-solving-based e-learning module. The purpose of this research is to find out what the students need in learning physics which results in the need to develop a problem-solving-based e-module on physics learning. The results of the analysis of 102 students suggested that 63.7% of the students use printed books in learning, which, according to students, are less practical. Moreover, as many as 61.8% of the students experience problems in problem-based learning, meaning that students have problems in analysing problems as well as interpreting and evaluating problemsolving; therefore, problem-solving-based learning is needed. As many as 59.8% of the students don’t learn independently, meaning that students are very dependent on the role of the teacher. Furthermore, based on the results of the survey, 53.9% of the students feel more enthusiastic if the learning uses technology, and 66.7% considered the concept of projectile motion as difficult. These results indicate that it is necessary to develop teaching material in the form of problem solving-based e-module for projectile motion as a physics learning medium to train students’ conceptual understanding in the city of Pekanbaru.
Technology-assisted Language Learning: Friends or Enemies
Authors: Farikah Farikah , Normawati Afi , Mulyani Mimi , Astuty Astuty , Cahyaningrum Aulya
Published: August 2023

This case study compared learners’ perspectives regarding using technology as a learning device. A total of 35 university students completed virtual interviews to collect information dealing with the student’s perspectives on technology-assisted language learning. They completed virtual interviews on their responses to technology implementation during the online teaching-learning process. The virtual interviews were conducted casually and followed the procedures of ’narrative interviewing.’ The discussions were started by asking some questions about the general experience of using technology during the teaching-learning process at university. The thematic analysis of qualitative data supplemented the interview findings by providing insights into why technology assists language learning during online learning. In general, however, most students argue that using technology as a tool for online learning has three roles. They are helping students find information, minimize the virus’s spread, and facilitate learning. This study demonstrated the potential of technology for assisting language learning during virtual learning.