bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of some physico-chemical properties of Elaeagnus L. GUM
Authors: Abdullaev O. G. , Umarov A. V. , Abdukelimu N. , Aisa H. A. , Abdullaeva B. S.
Published: August 2023

As is known, most polysaccharides have biological activity, play important roles in life processes, and are widely used in healthcare, food processing, and cosmetic production due to their therapeutic effects and relatively low toxicity. Among polysaccharides, this class’s representatives do not have a biological activity to some pathogens of diseases but have a huge potential to use them in various sectors of the national economy, such as in the food industry, cosmetics, and pharmaceuticals. One such polysaccharide is the gum obtained from the plant Elaeagnus L. germinating in the Xinjiang Uygur Autonomous Region of China and Central Asia. The local people call it jidah. This article is devoted to the extraction, purification, the determination of the monomeric composition, molecular weight, viscosity, spectral analysis, and some chemical properties of the polysaccharide obtained from the gum of the named plant Elaeagnus L.
Deformation and damage capacity of thin–walled rods and tubular conduits under alternating loading
Authors: Abdusattarov Abdusamat , Ruzieva Nodira , Abdukadirov Farxod
Published: August 2023

The paper presents deformation and elastoplastic calculation of thin–walled rods (pipelines) under spatial – alternating loading taking into account damageability of material. On the basis of deformation theory and variational principle of Hamilton – Ostrogradsky the system of differential equations of motion (equilibrium) under alternating loading is obtained and the boundary value problems for structural elements are formulated. The algorithms and results of realization of calculation of thin–walled rods (pipes) under alternating loading in view of damage accumulation are given. Numerical results of displacement and force components depending on the number of loading cycles with regard for strain diagrams are given. Effects of secondary plastic deformations and elastic unloading on stress–strain states are shown graphically.
Study of the hydraulic parameters of the flow of solid particles in the process of hydrotransport
Authors: Babaev Askar , Teshabaeva Elmira , Obidjonov Axror , Chorshanbiev Umar
Published: August 2023

The article presents the characteristics of transferring solids together with water in the process of hydrotransport at pumping stations, that is, the influence on the distribution of kinematic and dynamic parameters of the flow of hydraulic transport, the description of the pressure dispersed flows in the process of hydrotransport with high volume concentrations and a wide range of particle sizes and densities of solid particles that form mixtures.
Study of the Composition and Model Parameters of Complexes Formed in Fe(II)-Fe(III)-Ascorbic Acid-Water Systems
Authors: Davlatshoeva Jahongul , Rakhimova Mubashira , Eshova Gulrukhsor
Published: August 2023

The redox system Fe(II)-Fe(III)-ascorbic acid-water at 298.16 K and 0.5 mol/l solution ionic strength was studied by the Clark-Nikolsky redox potential method. It was found that five complexes of Fe(III) composition are formed in the system: [Fe(HAsc)]2+; [Fe(HAsc)]+; [FeIIFeIII(HAsc)2(OH)2]+; [FeAsc]+; [Fe(Asc)2]-and four coordination compounds Fe(II)-[Fe(HAsc)]+; [FeIIFeIII(HAsc)2(OH)2]+[Fe(HAsc)2]0; [Fe(Asc)]0. Models of ionic equilibria have been compiled, and the domination areas of the complexes have been determined.
Dirichlet’s problem for a third-order parabolic hyperbolic type equation of the second kind
Authors: Abdullaev A. A. , Xolbekov J. A. , Axralov H.
Published: August 2023

Equations of mixed type, the degeneracy line of which is the envelope of a family of characteristics, therefore, is itself also a characteristic, in the literature it is customary to call equations of mixed type of the second kind, which causes additional difficulties in the study of boundary value problems for equations of the second kind. In the present work, a boundary value problem for a homogeneous equation of parabolic-hyperbolic type of the third order of the second kind is investigated. Necessary and sufficient conditions for the existence and uniqueness of a generalized solution of the problem are found. In some special cases, the representation of the solution of the problem under study is written out explicitly.
Computer simulation of a push-pull power amplifier
Authors: Aripov K. K. , Aripova U. K. , Toshmatov Sh. T.
Published: August 2023

The paper presents the results of computer simulation of power amplifiers based on bipolar and complementary Darlington transistors. It is shown that the constant voltage gain is ensured by changing the current gain in the range from 103to 105.
The transformation of organizational culture to corporate culture in joint stock companies
Authors: Sadikova M. A. , Umarxodjayeva M. G. , Akramova N. I. , Yusupov A. R.
Published: August 2023

The introduction of effective corporate governance elements in order for companies to win in healthy competition in the conditions of a market economy will serve to increase the profitability of companies. Companies implement an individual corporate culture, depending on the type and nature of the activity. This article examines the processes of transformation of organizational culture into corporate culture, the impact of corporate culture applied in the process of transformation of commercial banks on the competitiveness of the company.
Study of structure and properties of biodegradable composite films based on thermoplastic starch
Authors: Turdikulov I. H. , Saidmuhammedova M. Q. , Atakhanov A. A.
Published: August 2023

The increasing use of plastic products is causing pollution of nature with micro plastics, plastic waste and harmful substances. In this work, the possibility of obtaining thermoplastic starch was studied; its structure and properties were investigated. The biodegradable compositions based on polyethylene-starch and polyethylene-thermoplastic starches were obtained, in which starch was used as a filler in the polyethylene matrix. Comparative studies of composites properties, such as optical, physic-mechanical, rheological and biodegradability were carried out. The polyethylene-thermoplastic starch-based composite films with biodegradable properties can be used as packaging materials instead of packaging polyethylene bags.
A study of the process of printing patterns on mixed fabric
Authors: Irmatova Mukharram , Nabieva Iroda , Sharipova Nilufar
Published: August 2023

The article explores the possibilities of printing patterns using pigments in two stages on a cotton-polyester fabric with different fiber ratios. A two-stage pattern printing technology with active and dispersed dyes has been developed to apply withfor cotton-polyester fiber fabrics.
Econometric modeling and forecasting the development of the postal service in Uzbekistan
Authors: Otakuzieva Z. M. , Otakuzieva S.
Published: August 2023

This article is devoted to econometric modeling and forecasting of development of postal services in Uzbekistan. As a result of digitization and optimization of postal services using the VAR and ARDL models with 2SLS, the number of post offices, the number of postmen closely associated with it, has been shown to decrease.
Potential distribution over temperature sensors of p-n junction diodes with arbitrary doping of the base region
Authors: Bebitov Rakhim , Abdulkhaev Oybek , Yodgorova Dilbara , Istamov Damir , Khamdamov Giyos , Kuliyev Shukurullo , Abdullaev J. Sh. , Khakimov Alim , Rakhmatov Akhmad
Published: August 2023

In p-n-junction temperature sensors connected in the forwardbiased, the temperature dependence of the built-in potential is important, while in the reverse biased p-n-junction temperature sensors, it is necessary to study the temperature dependence of the built-in potential and space-charge region width.For this case, as well as for homogeneous and gradient alloyed cases, the temperature dependence of built-in potential and space-charge region widthare studied and mathematical analysis is presented for these cases.Based on these mathematical analysis, the results are obtained for cases where the base region of p-n-junction temperature sensors is doped at different concentrations with a homogeneous or inhomogeneous distributions of impurities. It is well known that in conventional temperature sensors, when the main current transport mechanism is determined by generation-recombination processes in space charge region, the dependence of the space charge region width on the temperature can affect the linearity of temperature response curve of sensor, it is desirable to increase the doping rate of the base region to weaken this effect, or it is necessary to use p-n junction.
Development of methods for discoloration and bleaching of textile waste
Authors: Abdumajidov Anvar , Nishanova Saodat , Miratayev Abdumalik , Nabiyeva Iroda
Published: August 2023

This article presents the results of research experiments conducted to study the process of decolorization of fibrous waste generated at different stages of the textile industry in order to use it in the production of paper types.
The importance of cloud computing trends and the conceptual model in higher education for sustainable development
Authors: Zaripov Bahodir , Mirzaliev Sanjar , Sharipov Zayniddin , Xakimov Bahodir , Xudayqulov Rustam , Aziz Ahmed , Sharipov Kongratbay
Published: August 2023

Computing increases the flexibility and access of educational users to a wide range of educational resources. This includes access to infrastructure, software, hardware, and platform at any time in any place provided there is internet access. Current research trends on cloud computing have sought to study the acceptance or adoption of technology; however, little research has been devoted to the continuance use in an organizational setting. To address this gap, this study aims to investigate the antecedents of cloud computing continuance use in HEIs. The collective nature of all these entities is known as the Cloud. While respondents from all types and sizes of institutions showed some similarities in their perceptions of the cloud and cloud usage, there are some notable differences that are highlighted in the key findings. This paper also aims to identify the benefits and limitations of SaaS in higher educational institutions, closes with a discussion of the research limitations, contribution, and future directions
The effect of a seismic wave on a two-span beam on rigid supports interacting with the ground
Authors: Berdibaev Mars , Mardonov Batir , Nishonov Nematilla , Baybulatov Khayrilla
Published: August 2023

The transverse vibrations of a two-span beam bridge, the shore supports of which interact with the surrounding soil during seismic action, are considered. The condition is accepted that the deformations of structures do not go beyond the limits of elasticity and vibrations are linear in nature. The bridge supports are assumed to be submerged in the ground and interacting with a rigid body under the action of non-stationary dynamic influences. The case is considered when the left, middle and right supports have equal masses and interact with the surrounding soil in the same way. The symmetry condition is applied, and it is sufficient to consider the equation of the right half of the beam. The problems are solved by the analytical Fourier method under the given boundary conditions. The results obtained are presented in the form of stress distribution over time and length of bridge structures, and their analysis is also presented.
Optimal distributed generation allocation in distribution system for power loss minimization and voltage stability improvement
Authors: Khasanov Mansur , Kamel Salah , Nazarov Furqat , Rizayeva Maxzuna , Shodiyeva Nozina
Published: August 2023

Voltage instability and power loss are significant problems in distribution Systems (DS). However, these problems are usually mitigated by the optimal integration of distributed generation (DG) units in the DN. In this regard, the optimal location and size of the DGs are crucial. Otherwise, System performance will deteriorate. This study is conducted to place the DGs in the radial DS. Mayfly Algorithm (MA) is used to determine the optimal placement and size of the DGs to minimize power loss, increase voltage stability in radial DS. The simulation results showed a reduction in the percentage of power loss is 69.14% for three PV-type DG unit integration. The corresponding percentage of power loss reduction is 98.09 % for three WT-type DG units by installing DG units to the test System. Similarly, the minimum bus voltage stability improves to 0.959 per unit for three PV type DG unit integration. The VSI after DG allocation increases to 0.989 per unit for three WT type DG units by optimal installing DG units. Comparative studies have been conducted, and the results have shown the effectiveness of the proposed method in reducing the power loss and improving the voltage stability of the DS. The proposed algorithm is evaluated in the IEEE-69 bus radial DS using MATLAB.
Analysis of changes in moisture transport parameters in soils under waterlogged conditions
Authors: Saliev Bakhodir , Melikuziyev Sarvar , Mirnigmatov Shukrullo , Sultonov Rustam , Bahodirov Shohruh , Khusenov Ulmasbek , Allayarov Timur
Published: August 2023

The article considers changes in natural patterns of moisture transport parameters under waterlogging and lowering of groundwater table, in conditions of filtration-anisotropic strata. The nature of anisotropy characteristic of river sediments (alluvial, pluvial, deltaic and their combinations) is the most widespread in the surface zone of the earth’s crust. Impact factors: external and artificial, in the process of waterlogging and drainage, affect both positively and negatively the thickness of the active zone, capacity and water permeability values. The research method is based on the generalization of different approaches, causes and factors of moisture movement and on the results of field experiments to determine the nature to reveal the essence of “gravity moisture discharge”. In more exact statement the problem of stationary filtration is solved by Laplace equation. The state of moisture in the aeration zone has been studied: unsteady, transient and gravitational. By investigating the nature of this process, it is established that the evaporation process takes place not from the surface of groundwater table, but from aeration zone located between air (above ground surface) and water space (lower boundary of aeration zone).
Features of spectral vibration diagnostics of traction power transformers in high-speed motion
Authors: Amirov Sulton , Yakubov Mirjalil , Jurayeva Kamila , Saydivaliyev Saidaziz
Published: August 2023

This paper uses spectral analysis methods to develop a mathematical model and algorithms for evaluating the diagnosed signals corresponding to certain defects of windings and magnetic circuits of traction power transformers. A distinctive feature of the study is at certain frequencies of spectral dependences, taking into account the effects associated with defect formation that have a different cause of their manifestation, for example, wide-field fluctuations and changes in the shape and width of spectral peaks. The presence of random fluctuations caused the application of the normal Gaussian distribution law of the measured values of the spectra. To solve the problem of identifying the diagnosed spectra corresponding to certain defects of the power transformer, algorithms for identifying the vector of diagnostic features based on the method of statistical recognition theory for large amounts of information are proposed.
Algorithm for adaptive observation based on method of instrumental variables
Authors: Nikolov Nikola , Alexandrova Mariela , Ubaydullayeva Shakhnoza , Gaziyeva Rano , Zulfiya Khafizova , Ubaydullayeva Dilorom
Published: August 2023

When the input signal and the output value of the object of control cannot be measured accurately, the state vector is estimated. The instrumental variables (IVs) method is a commonly used parameter estimation method [1-10]. The task of adaptive observation is to create state observers containing parameter estimators. In adaptive observers, the matrices A and b or c (depending on the chosen canonical state-space representation form) are assumed to be unknown. In the monitoring process, parameter estimation is performed, the unknown matrices are determined, and then the state vector is calculated. The paper aims to present a non-recurrent adaptive observation algorithm for SISO linear time-invariant (LTI) discrete systems. The algorithm is based on the instrumental variables (IVs) method, and the adaptive state observer (ASO) estimates the parameters, the initial and the current state vectors of the discrete system. The algorithm's workability and effectiveness are proved by using simulation data in MATLAB/Simulink.
Development of model and analysis of one-dimensional movement of ploughshare of subsoiler
Authors: Kuldoshev Davronbek , Djuraeva Nargiza , Urinov Aziz
Published: August 2023

Soil medium changes its structure and deforms when the actuating tool of an agricultural machine interacts with the soil. The effect of soil on the performance of the actuating tool can be taken into account through soil density and tensile strength. The model of a plastic medium proposed by Academician Kh.A. Rakhmatulin and simplified equations obtained based on the hypothesis of plane sections were used to describe the movement of soil near the point under finite deformations. It was stated that, depending on the coefficient of internal friction and cohesion of soil, a zone of high soil density could form near the actuating tool of the subsoiler ploughshare, where a significant increase in the resistance force is observed.
About rational number of spindles on drums of cotton harvester
Authors: Rizaev A. A. , Alimova D. B. , Omonov N. N. , Mamatmurodov I. A.
Published: August 2023

The technological process in a cotton harvesting machine is carried out mainly with the help of spindle drums, doffers, and mechanisms that set them in motion. The contact of the spindles in the drums with the open bolls of the cotton during the harvesting process is due to the quality of the harvest and the full set of parameters of the drums, which should be paid attention to: diameters, the number of spindles in them, kinematics, the size of the open bolls and the size of the cotton. The article presents the analytical expression linking the parameters of the drum and the open bolls of cotton based on the analysis of the results of studies conducted in this direction and experiments. The graphs were constructed that reveal the essence of this connection, and their analysis was given. The article presents the results of comparative experiments on the example of a vertically-spindle cotton harvester with two pairs of sequentially arranged spindle drums with 12, 14, and 15 spindles on each drum with the same diameter kinematic mode of its operation. The results of theoretical and experimental studies have allowed us to conclude that an increase in the number of spindles in front paired drums contributes to an increase in the completeness of cotton harvesting from open cotton bolls.
Improving energy efficiency of solar panels
Authors: Zikrillayev Khayrulla , Sodiqov Timur
Published: August 2023

This article is about a photovoltaic power plant built at the Korean side's expense, equipped with Korean-made solar panels, and where the author conducted scientific and practical research. The study used a scientific-practical, observational, comparative measuring method. All solar panel trackers were set at 30° degrees and not equipped with a sun tracking system, except for only one solar panel. The tracker of the TOP SUN module has a manual tracking system for the Sun, in which a person has to manually changes position from 15° to 45° degrees depending on the seasons. Thanks to the authors, a solar tracker has been developed to improve the efficiency of solar panels, which has a sun tracking system and low energy consumption, which is a key aspect. During the day, the solar panel parameters with and without a tracking system for the Sun were obtained; also, their power was calculated, and for comparison, a graph of the power difference was plotted. On average, a solar panel with a solar tracking system generates 30 % more energy than a solar panel without a tracking system.
Diagnostics system for plant leaf diseases using photo images
Authors: Muhamediyeva Dilnoz , Tukhtamurodov Nozir
Published: August 2023

The subject under consideration is the issue of detecting agricultural crop diseases. The preliminary data for determining the phytosanitary status of cultivated plants are the images of their leaves. To tackle this issue, a model of diagnostic algorithms has been proposed, which involves creating a set of preferred characteristics and making diagnostic decisions based on comparing these features. The process of establishing the model of diagnostic algorithms has been outlined. The effectiveness of the proposed model has been demonstrated in diagnosing wheat diseases based on leaf images.

A novel technique for detecting plant diseases has been introduced, relying on digital RGB photographs of leaves in the visible spectrum. The novelty of this method lies in diagnosing visible symptoms of plant leaf diseases from photographic images. There is a significant number of plant diseases that can reduce productivity, resulting in economic and environmental damage. Consequently, the accurate and timely diagnosis of plant diseases is paramount. One widely used approach for detecting plant pathologies involves using convolutional neural networks to diagnose plant leaf diseases from photographic images.
Formation of diffusion nitride-oxide coatings
Authors: Boynazarov Urol
Published: August 2023

It is known that nitro-oxide coatings were developed based on nitriding, which are obtained using a two-stage technology consisting of nitriding at the first stage of the process and vaporization at the second stage. Such processing provides high physical and mathematical characteristics of hardened parts.

This technological process was improved by us due to preliminary oxidation, which made it possible to accelerate the production of nitride-oxide with the necessary physical and mechanical properties.

This work makes a theoretical calculation of the oxidation processes and subsequent nitriding of steels and a comparison with experimental data on the example of 38X2MYA. The article presents an analysis of the formation of oxynitride diffusion protective layers obtained by a three-stage nitriding method at a temperature of 580° C, which consists of preliminary oxidation, nitriding, and subsequent steam oxidation. The article also describes the effect of the oxide film on the nitriding process during preliminary oxidation and nitriding under short-term conditions at a temperature of 580 S.
Technology and machine tape preparation soil for seeding
Authors: Mamatov F. M. , Ergashov G. X. , Ravshanova N. B. , Temirov I. , Babajanov L. K.
Published: August 2023

Mutual arrangement is a combined machine that performs strip preparation of the soil for sowing. The scheme and the functional scheme of the combined machine are given. Analytical dependences and mathematical models for determining the distance between the support wheels are obtained. In this case, the methods of theoretical and classical mechanics are used. To conduct experimental studies, a strain gauge laboratory and field installation has been developed with the possibility of changing the sheet casing, the ripper, and the main housings. Machines were determined in experiments. The plowshare of the lister housing and the ripper of at least 40 cm, between the main body and the lister housing of at least 70 cm, high-quality soil preparation for sowing melons of the required degree with minimal traction resistance.
Potato digger with latticed plowshares and oscillating rods
Authors: Mamatov F. M. , Karimov A. A.
Published: August 2023

The process of digging potatoes is characterized by high energy costs due to the interaction of the potato digger's plowshares with the tuber-bearing soil layer. The study aims to substantiate the parameters of potato digger's lattice plowshare. In the proposed potato digger, the plowshare is made latticed and equipped with oscillating rods. This potato digger has a mechanism for transmitting torque to oscillating rods. The experiments were carried out using a special laboratory-field installation. Various lattice plowshares were manufactured, and single-factor experiments were carried out. During the experiments, the degree of damage and loss of the tuber and the traction resistance potato digger were taken as evaluation criteria. The results of experimental studies to determine the parameters of plowshare are presented. It is established that the optimal design scheme for a potato digger consists of torque transmission mechanisms, lattice plowshares, and forcibly oscillating rods. As a result, theoretical studies, analytical dependencies, and mathematical models were obtained to determine the parameters of a lattice plowshare. Studies have established that to destroy the tuber formation to the required extent with minimal damage and loss of tuber, as well as energy costs, the width lattice plowshare should be 55 cm, the angle plowshare installation relative to the horizon is 22°, the length plowshare is 38 cm, and the width gap between the bars is 3 cm.
Parameters of passive working bodies of potato digging machine
Authors: Mamatov F. M. , Rustamova N. R. , Chuyanov D. Sh. , Toshtemirov S. J. , Kurbanov Sh. B.
Published: August 2023

The major working housing of potato digging machines is a plowshare on which energy costs and the quality of potato digging depend. The examination aims to justify the parameters of the plowshare and the divider of the combined digging working body. The constructive scheme of a potato-digging machine with a combined digging working body, the results of theoretical studies on the substantiation of the primary parameters of the main and intermediate plowshares and the divider, are presented. A special laboratory installation was used to conduct experiments. During the experiments, dividers with different capture widths were made, and the angle of the plowshare installation to the horizon was changed. The degree of damage and loss of the tuber and the traction resistance of the plowshares were taken as evaluation criteria. The outcome of the experimental investigation to determine the parameters of the plowshare is presented. Based on theoretical studies, analytical dependencies, and mathematical models were obtained that allow determining the parameters of the plowshare and the divider of the potato digging machine. It was found that for intensive destruction of the tuberous formation with minimal energy consumption and uniform transportation, the width of the colter of the combined working housing must be 45 cm, the perspective of the plowshare razor solution 90°, the perspective of inclination of the plowshare to the skyline within 27-30°, the length of the plowshare 40 cm, the width of the divider should be 45 cm, its length 39 cm, the angle the solution is 60°, the angle of installation of the working surface to the horizon in the transversely vertical plane is 65° and the range from the toe of the intermediate plowshare to the divider is 32.6 cm.
Dynamic models and analysis of overflow of upper level of GTS for their automatic protection
Authors: Usmanov A.M. , Yadgarova D.B. , Nig’matov A.M.
Published: August 2023

A catastrophic increase in the supply channels of hydraulic structures on canals should be controlled, and automatic headwater protection from overflow should be carried out. Knowing the dynamic model of such a process, it is possible, according to a previously developed algorithm, to generate a control signal at the beginning of the transient process to prevent an emergency. The reasons were analyzed as threats leading to the overflow of the headwater, among which non-discharged sediments stably intensify the dynamics of the transition process. A control system simulation model was created in the MatLab environment, the coefficients were determined, and the dynamic characteristics of the pool overflow process were built. In this case, the time constant was 7 seconds, and the removal of the control signal was possible within 1-3 seconds after the start of the transition. Reducing the probability of a pool overflow threat is predicted to be within 25%.
New technology for primary purification of sunflower and soybean oils
Authors: Akhmedov Azimjon , Erkaeva Nodira , Rakhmonkulova Oksana
Published: August 2023

This article presents the results of the return of a high-oil fuse for frying, and its further pressing; the acidity of the resulting oil reached 5-6 mg KOH, which is 2-3 units higher than the technological norm. To reduce the acidity of black oil to normal, additional costs are required for refining. According to the proposed method, after 5 hours of operation of the production line, the acidity of the black oil decreased to 1.2 mg KOH, which contributed to an increase in the yield of refined oil by 2.5%.
Role of process of interdisciplinary integration in courses to students of technical higher education institutions
Authors: Sharipov E. O. , Radjabov M. R. , Rustamov M. , Murodullaev J.
Published: August 2023

This article presents examples of creating a projection of a point in space onto the plane in the discipline of "Higher Mathematics" and "Engineering and Computer Graphics" and creating a projection of a point in space onto a plane.
Parameters of finger stalk lifter cut branches in intensive gardens
Authors: Shoumarova Muxayyo , Abdillaev Tulegen , Berdimuratov Parakhat , Jakhongirov Daurbek , Tadjimuratova Aziza
Published: August 2023

In Uzbekistan, the areas of intensive orchards are expanding, in which branches are regularly pruned according to agrotechnical rules.

In intensive orchards, the number of fruit trees is usually greater, so cut branches occupy most of the row-spacing area. They interfere with many operations, so they must be removed. Usually, this work is done manually. True, some rakes collect cut branches and take them out of the field. The parameters of existing rakes do not always meet the requirements, so the authors proposed a branch pick-up that works satisfactorily. This article provides a rationale for its kinematic parameters. This branch pick-up also allows you to pick up short-cut branches in intensive orchards.
Technologies to reduce water waste during land leaching and cultivation of industrial crops
Authors: Begmatov Ilkhom , Khajiyev Masharif
Published: August 2023

More than half of Uzbekistan's irrigated land is saline to some degree. The drying up of the Aral Sea has intensified this process. For many years, chronic salt storms in the northern part of the country have sprayed large quantities of salt onto agricultural land, leading to increased salinization. These processes cause the water required to flush saline soils year after year.

The problem is exacerbated by water shortages worldwide, including in Central Asia. This requires the leaching of saline soils and a multiplication of the water used in crop cultivation. Therefore, alternative use of water resources in our country is one of the most important issues for agriculture. The introduction of salt leaching and cultivation in farms based on outdated technologies and the low efficiency of new technologies (bio-solvent washing, etc.) in the production of new salt leaching and cultivation remain a negative obstacle for the economic development of farms and the country as a whole.

The analysis shows that in our country, billions of cubic meters of water are used to flush saline soils and cultivate agricultural crops. Still, only 60% of this water reaches the fields where crops are grown, while the rest of it disappears into the irrigation systems and irrigation processes (canals, ditches, and branch lines).

When providing water resources for soil salinization and cultivation using trapezoidal canals, part of the water flowing through them dissolves and filters the mineral and organic fertilizers in the soil due to air pressure and gravity; as a result, up to 30% of water is lost (wasted). In this paper, the water resources for soil washing and crop cultivation are replaced by a parabolic excavator with a trapezoidal boom, designed to save up to 30% of water resources.
Issues of digitalization of machine and tractor fleets in agriculture
Authors: Kulmatova Sayyora , Khatamov Ochildi , Yusupova Dilbar
Published: August 2023

The article describes an intelligent machine and tractor fleet in agriculture. The article also describes smart technologies that facilitate participants' work in agricultural management and maintenance systems in machine and tractor fleets.
Parameters of slitter for embedding manure in soil for melon crops
Authors: Chuyanov Dustmurod , Kholikova Nargiza , Shodmonov Golib , Buriyev Muhriddin
Published: August 2023

The purpose of the study is the theoretical justification of the parameters of the slitter for embedding manure in the soil. A slitter has been developed for lifting the formation, forming a gap along the manure strip lying on the field's surface, pushing it into the gap, and leveling the gap with soil. The basic principles and methods of classical mechanics, mathematical analysis, and statistics were used in this study. The slitter includes a rack, large and small cheeks connected to a soil-supporting plate with an increasing slope from the bottom to the top towards the small cheek and adjacent to the soil-supporting plate. A window is made in the big cheek for the passage of manure. The large cheek is somewhat pushed forward relative to the soil-bearing plate, and its front face is pointed. It is established that when planting fertilizers, the following operations must be carried out: lifting the formation, forming a gap along the manure strip lying on the field's surface, pushing the latter into the gap, and leveling the gap with soil. The working bodies of the dump type are the most acceptable for lifting the formation and the formation of a gap. The following optimal values of the parameters of the slitter are established: the removal of the large cheek is 710 mm, the width is 200 mm, the length and height of the window are 550 and 250 mm, respectively, and the angle between the forming and field edge in the horizontal plane is 42°, the height of the small and large cheeks of the slitter is 300 and 250 mm, respectively.
Technological basis of rotation of body with polygon
Authors: Kurbanov Sherzod , Temirov Isroil , Babajanov Laziz
Published: August 2023

Front-end plows are promising and carry out smooth plowing. A significant disadvantage of the front plow is that the housings do not completely rotate the layers within their own furrow and have a large traction resistance since they work in conditions of blocked cutting. The study aims to substantiate the technology of turnover of a polygonal formation in conditions of non-blocked cutting. The basic principles and methods of classical mechanics, mathematical analysis, and statistics were used in this study. The parameters of the polygonal formation formed by the angle beam and the body of the plow have been studied. Analytical dependences for determining the coordinate of the center of gravity of the formation and the displacement of its center of gravity along the ordinate axis are obtained. It was found that the displacement of the center of gravity of the formation along the ordinate with a formation width of 45-52.5 cm and a gripping width of the angle of 4-10 cm is 4-10 cm.
Synthesis of superplasticizer for concrete mixtures based on naphthalene
Authors: Kenjaev Akmal , Nurmonov Suvonqul , Kodirov Orifjon
Published: August 2023

In subsequent years the construction industry in our country is developing very rapidly. Accordingly, the requirements for the rational and efficient use of raw materials and energy resources in building materials are also increased. To effectively solve the problem of developing prefabricated, monolithic concrete and reinforced concrete structures with high strength and durability of concrete mixtures, and special chemical additives, the widespread use of superplasticizers is required. In particular, obtaining such products based on industrial secondary raw materials is more important.

Pyrolysis of hydrocarbon raw materials is the main method for obtaining low molecular mass olefins, mainly ethylene, propylene, and acetylene. The increasing production of ethylene and propylene has also led to increasing by-products generated in this process. A large amount of pyrolysis oil as a by-product is also obtained at pyrolysis. During the investigation, a naphthalene fraction was isolated from this product, and on its basis, a synthesis of superplasticizer for concrete mixtures was carried out.
Longitudinal vibrations of underground pipelines of finite length in medium surrounded by soil with different properties along pipeline length
Authors: Khusainov R. B. , Yuldoshev B. Sh. , Abdullaev D. , Khusainov S. B.
Published: August 2023

An analysis of the dynamic response of an underground main pipeline under a longitudinal wave propagating in soil along the pipe is given in the article. The problem of the longitudinal wave impact on a pipeline of finite length, interacting with soil according to the elastic-viscous law, is considered. The ends of the pipeline are fixed to massive nodes that interact with the medium according to linear laws. Along the length of the pipeline, the coefficients of the elastic and viscous pipeline-soil interaction change depending on the coordinate. In this article, the influence of the coefficients of elastic and viscous interaction of the "pipe-soil" system is studied when these coefficients are coordinate functions. The variability of the values of the coefficients along the length of the pipeline leads to a change in displacements from 0 to 15% and strain from 0 to 18%, compared with the case when these coefficients are constant. Depending on the length of the pipeline, the response of the pipeline to seismic action is different. This is especially evident at the boundary points. Considering the weight of nodes leads largely to a decrease in the strain of the pipeline relative to the soil strain at the boundary points.
Development of wastewater treatment technology with purpose of their reuse in process of obtaining cotton pulp
Authors: Sayfutdinov Ramziddin , Mirsaidova Kamila , Mirkamilov Shuxrat , Gullieva Yulduzkhon , Usmankhodzhaeva Iroda
Published: August 2023

Today, an urgent problem is developing a technology for producing cotton cellulose from low-grade linters with the rational use of water resources. This issue is especially relevant for the Republics of Central Asia.

Also, the development of a technology for the production of cotton pulp would provide an acute shortage of pulp and paper, protect the environment, reduce energy costs, reduce water and chemical costs, and rationally use available raw materials.

The paper presents the results of studies on the possibility of cleaning waste liquor and wash water for reuse in obtaining cotton cellulose. The object of the study is the cooking solution, spent liquor, used water after pulping and washing, their sanitary characteristics, and the quality indicators of the products obtained.

The discoloration of wastewater, the residual amount of sodium hydroxide, the change in the optical density of the cooking solution, and the chemical composition of the waste liquor and washing water after discoloration were experimentally studied.
Free boundary problem for predator-prey model
Authors: Elmurodov Alimardon , Norov Abduraxmon , Yuldasheva N. , Yuldashev Sanjarbek , Sadullayeva Mavjuda
Published: August 2023

In this article, we study the behavior of two species evolving in a domain with a free boundary. This system mimics the spread of invasive or new predator species, in which free boundaries represent the expanding fronts of predator species and are described by the Stefan condition. A priori estimates for the required functions are established. These estimates are used to prove the existence and uniqueness of the solution.
Change in wear resistance of alloy when alloying aluminium alloy with germanium oxide
Authors: Tursunbaev Sarvar , Turakhodjaev Nodir , Odilov Furqat , Mardanokulov Sharofiddin , Zokirov Ruslan
Published: August 2023

Various studies are being conducted on alloying materials for mechanical engineering with various unique elements. In particular, studies have been conducted to improve its properties by including elements such as lithium, zirconium, ytterbium, and erbium in the composition of the aluminum alloy. The article examines the change in the wear resistance ability of alloys in aluminum-silicon and aluminum-copper systems with germanium oxide based on their mechanical properties. The samples were poured into a resistance furnace. In this case, a germanium oxide compound was added to the charge of one to three percent. Wear resistance was determined using a diamond stone meter. At the same time, the samples were measured on the device with the strength of wear resistance at certain intervals. Based on the results obtained, a graph of the dependence of the wear resistance of the samples on the GeO mass was developed. The conclusions of the authors based on the results obtained are given in the final part of the article. The study was tested in the laboratory of the Department of Foundry Technologies of Tashkent State Technical University.
Theoretical description of marketing system of automotive enterprises
Authors: Sharipov Kongratbay , Zaynutdinova Umida
Published: August 2023

The article examines the issues of using benchmarking to increase the competitiveness of auto industry enterprises. In the present conditions, the interaction concept in the marketing activities of auto industry enterprises consists of relations (communication) between buyers and the participants of the buying and selling process; scientific proposals and recommendations are given to increase the importance of effective communication of marketing interaction. At the same time, it is important to effectively influence the marketing system of auto industry enterprises by implementing the results of marketing research of international research institutes in forming directions for increasing the effectiveness of the marketing activities of auto industry enterprises, and as a result, to increase the investment potential and competitiveness of auto industry enterprises. Studying the theoretical foundations of the formation of marketing strategies in the automotive industry and approaches to classifying the types of marketing strategies allow to determine the peculiarities of their use in the automotive industry of Uzbekistan and to develop appropriate measures. The analysis of the characteristics of the main methodological approaches to the development of marketing strategies of automobile industry enterprises in foreign countries practically substantiates the fact that the flexibility to the processes related to market development is important, not the relationships that arise during the development of the marketing strategy and its implementation.
Efficient reception of introducing basalt fiber in cement matrix of fiber concrete
Authors: Mukhamataliyev Irkin , Ruzmetov Fazliddin , Khudoyorov Azamat , Uzakov Sherbek
Published: August 2023

The article is devoted to solving the problem of the distribution of basalt fiber in the environment of the filled cement paste and the total volume of basalt fiber-reinforced concrete, which is one of the most important in the preparation of basalt fiber-reinforced concrete. This article presents the results of experimental studies to establish the most effective technological method of introducing basalt fiber into the cement matrix of the composite from the point of view of increasing the strength characteristics of fiber-reinforced concrete. In the experimental studies performed, standardized methods for the study of cement paste and stone were used. As a result of the research, graphical dependences of the strength and water demand of a dispersed-reinforced cement stone on introducing basalt fiber into the composite and the quantitative content of basalt fiber in the composite were obtained.

The analysis of the obtained results made it possible to establish that of the various methods for introducing basalt fiber into the cement matrix of basalt fiber-reinforced concrete, the most effective in terms of increasing the strength of the composite material, provided that the water demand of the fiber-reinforced concrete mixture remains unchanged, is preliminary dry mixing of cement with basalt fiber in a spring mill. The most favorable environment for the mechanical activation of basalt fiber in a spring mill has also been established, which makes it possible to achieve high rates in terms of the preservation of basalt fiber during joint grinding. The scientific novelty of the performed research lies in the fact that the issue of studying the distribution of basalt fiber was first studied at the level of the microstructure of basalt fiber-reinforced concrete.
Impact of bombardment by Ar+, Na+ and O2+ ions on spectra of elastically scattered electrons of single-crystal Ge
Authors: Abraeva Sevara , Tashmukhamedova Dilnoza , Gulyamova Soadat , Yusupjanova Mahsuna , Xujaniyazova Aziza
Published: August 2023

The impact of bombardment by Ar+, Na+, and O2+ ions on crystal structure, composition, and excitation energy of plasma oscillations and band-to-band transitions, was studied using elastically scattered electron spectroscopy. It has been shown that, regardless of the type of ions, after bombardment with ions with E0 = 1 keV at saturation dose D = Dsat, the near-surface layers of Ge(111) were subjected to significant disorientation. While in the case of bombardment by Ar+ ions, we don’t see any noticeable change in the composition, energy of band-to-band transitions, and excitation of plasma oscillations, the bombardment by Na+ and O2+ ions appear to lead to the formation of compounds between atoms of Ge and dopant atoms. As a result, we witness a somewhat dramatic change in the structure of the spectrum of elastically scattered electrons (ESE); in particular, the spectrum changes dramatically: in the range Ep ≤ 25 − 30 eV, whereby all features pertinent to Ge(111) seem to disappear altogether whereas those formerly unknown do appear instead. After heating of Ge(111) previously implanted by Na+ ions at T = 750 K, a continuous homogeneous NaGe film with a thickness of 35−40 Å is formed, and in the case of O2+ A GeO2 film with a 20−25 Å thickness formed at T = 850 K. The share of ion bond and the charge quantity Δq transferred by cation to anion were determined judging by a chemical shift of M45 core level peak of Ge.