bluuebunny/crossref_metadata_2025_split huggingface dataset:
Method for calculating the porosity of cement composite materials using X-ray computed tomography
Authors: Sharanova Anastasia , Dmitrieva Maria , Leitsin Vladimir , Shinyaeva Maria 
Published: January 2021

Abstract
X-ray computed tomography is a promising method for non-destructive testing of the internal structure of materials. The article provides an overview of the use of computed tomography to study the structure of cement-based composite building materials. Computed tomography of four samples of fine-grained concrete mixture was performed: basic composition and compositions with different contents of additives of redispersible polymer powder and calcium formate. A method for calculating the porosity in these samples using a constructed 3D model and special software is presented.
Equivalent viscous damping ratio for a RC column under seismic load after a fire
Authors: Tamrazyan Ashot , Chernik Vladimir 
Published: January 2021

Abstract
The problem of taking into account combinations of special influences in the design of buildings and structures is currently quite relevant. In the event of a combination of fire and seismic load, two options are possible: fire after an earthquake and an earthquake after a fire. This work is devoted to the development of the methodology for calculating RC columns when the second option appears. It is known that fire effects reduce the mechanical characteristics of concrete and reinforcement. When calculating for seismic loads, it is also important to understand how the properties of a structure change during heating to dissipate deformation energy under low-cycle loads. When calculating RC columns using the displacement based design (DBD) method, dissipative properties are estimated the viscous damping ratio. In this work, this ratio is determined by considering the energy losses in one cycle of oscillations, which are equal to the area of the hysteresis loop. Hysteresis loops are determined by numerical calculation of RC columns for a combination of vertical preload and quasistatic horizontal displacement. The mechanical properties of the columns correspond to different fire times: 0, 30, 60, 90 and 120 minutes. In numerical modeling, it was found that the total energy that the column is capable of dissipating decreases with increasing duration of fire exposure. In its turn the hysteresis damping ratio at different fire duration can be either more or less than its initial value. The hysteresis damping coefficient decreases only for a time of fire of 30 and 60 min. With a longer fire duration (90 and 120 min), the coefficient does not decrease.
Influence of lowering groundwater level on the behavior of pile in soft soil
Authors: Znamenski Vladimir , Hegazy Osama , Sayed Diaaeldin , Thuy Duong Le 
Published: January 2021

Abstract
The article presents the results of numerical analysis of the development of negative skin friction forces of a single pile by lowering the level of the groundwater ta-ble in soft clay soils. The analysis is conducted with a three-dimensional model (3D) us-ing the ABAQUS software package. Results from the present work are found to be in congruent with the available published results. Moreover, the influence of lowering of the groundwater table in distribution of negative skin friction and axial forces on the pile as well as the maximum relative displacement between the soil and pile at various stages has been observed. The compression of the pile material is also taken into con-sideration in the study. Based on the results of the current numerical analysis, an equa-tion has been proposed for estimating the additional load on the pile, which is caused by negative frictional forces.
Use of natural the fracture of coal under the regulatory impact of water hammer in the coal-watercoal cluster of utilities sector
Authors: Chernyshev Sergey , Zommer Tatyana 
Published: January 2021

Abstract
The project to establish a prototype coal-coalwater cluster housing involves the use of constructed or existing boilers innovative coal-water-carbon technologies, including recycling and solid types of coal fuel in coal-water fuel slurry followed by burning in specially equipped furnaces. Analysis of the processes of brittle destruction of coal as a fractured rock at the macro and microlevels has shown that directed hydromining with the release of methane contained in coal seams, as well as wet grinding with the production of a certain granulometric composition of watercoal fuel suspension by hydroimpact occurs through macro-and microcracks. Also, as a result of the research, it becomes possible to use natural fracturing of control coal in the framework of creating a pilot site for an innovative coal-watercoal cluster of housing and communal services. A control model for an innovative coal-watercoal technology based on automatic control of the granulometric composition using of natural the fracture of coal the regulatory impact of water hammer is proposed. The technological regularities of reducing the negative technogenic impact on geospheres are revealed, including the method of managing the environmental and technological qualities of innovative coal-water suspension based on automatic control of the granulometric composition when grinding coal using the water hammer method.
Mathematical modeling of failure of port control systems
Authors: Khripko Tatyana 
Published: January 2021

Abstract
The need to increase the capacity of ports is due to the development of the Northern Sea Route as a national transport route of Russia in the Arctic, the National Program for the Development of the Far East, in the context of an increase in trade with other regions of Russia, as well as the reorientation of cargo flows from the Baltic ports to Russian ones in Primorsk, Ust-Luga and Vysotske. Increasing cargo turnover and ensuring the strategic economic interests of Russia requires the reconstruction of existing and construction of new modern port-industrial complexes, provided with advanced technologies, including the automation of logistics management processes, production and engineering systems. This article describes a method for mathematical modeling of the failure of control systems for automation of cargo terminals of ports. Since failures in the operation of automation systems lead to an increase in the load of cargo berths (terminals) of both sea and river port complexes, to a violation of logistics schemes, and as a consequence to an increase in costs. Modeling is carried out using methods of probability theory, in particular, the Poisson distribution law. A comparison of the empirical and theoretical failure rates of automation is performed using the Pearson criterion. The performed modeling will allow determining the technical and economic indicators of new construction, reconstruction or overhaul, in terms of the engineering systems of the facility, and optimize the automation processes.
Environmental monitoring in construction for hydro-technical structures and land reclamation facilities of Uzbekistan
Authors: Nasrulin Aydar , Ergasheva Dilbar , Khamdamov Bekmamat , Shadibekova Fatima 
Published: January 2021

Abstract
The article is devoted to the urgent topic of creating a comprehensive geographic information system for environmental monitoring and decision support for hydro-technical structures and land reclamation facilities of Uzbekistan. The research results allow a more substantial assessment of the environmental situation, the fundamental features of the arid zone. For monitoring, a methodology is disclosed, which will help water and water organizations to plan and predict the environmental status in the water sector. The results of a comprehensive analysis of the Aral Sea basin using geographic information systems will help in creating a decision support system. The excessive use of water resources within the Aral Sea basin for agricultural, industrial, and wastewater needs has resulted in the contamination of water resources by a diversity of hazardous chemicals from anthropogenic. Expert questionnaires for environmental measures developed during the reconstruction of hydro-technical structures and land reclamation facilities. They are using the methodology of environmental monitoring. It is possible to evaluate and improve the hydro ecological situation of hydro-technical structures and land reclamation facilities in Uzbekistan
Management of the waste of construction and demolition
Authors: Ostyakova A V , Mazurin D M 
Published: January 2021

Abstract
The problem of accumulation, transport and disposal of waste is currently the cause of environmental degradation of territories, so it is relevant. The main method of waste disposal in Russia is landfill disposal without additional disposal methods, including recycling. In recent years, technologies for handling construction and demolition waste have been developed so that they can be recycled after processing as raw materials, for example, in the construction industry or in road repairs. This will save primary natural resources and energy. The article uses the example of a specific project for the reconstruction of the building in Moscow to present the technology for handling of the construction and demolition waste during the dismantling of a building with the preservation of the facade wall. The classification of waste according to the Federal classification catalog of waste is given, the volume of waste generated is calculated, the term and organization of their temporary storage on the construction site is given, and the possibility and options for secondary use of this waste are analyzed. Based on the comparison of options, the route scheme for transportation of the construction and demolition waste outside the construction site to the landfill, where the recovery complex and the crushing complex are located. There the waste will be prepared for recycling.
Dynamic and kinematic conditions for designing water channels
Authors: Qosimov Jakhongir , Nasritdinova Umida , Nasritdinov Axmadjon 
Published: January 2021

Abstract
Studies are conducted for design institutes in which the mating structures of pumping stations (PS) are designed. In the regional conditions of the Republic of Uzbekistan during the operation of the PS, of particular importance is the problem of protecting equipment from pumps and fins, as well as the stability of water supply facilities and the creation of favorable hydraulic conditions for supplying flow to the pumps. The main factors in the conditions of flow inlet are calculations related to suspended particles.
Hydraulic characteristics of the water flow under the conditions of stationary inward flow over pipelines with protection coating
Authors: Bryansky Ilya , Bryanskaya Yuliya , Yumasheva Maria 
Published: January 2021

Abstract
While passing through waterbodies the pipeline crossings are affected by the inward flow. It might lead to soil erosion near it, and objects floating in this flow can cause damage of the pipeline, increasing risks of collapse. There are several types of protective coatings that are used on the pipelines, including the flexible protective concrete pavement (mats). Experience has shown that partial erosion of soil foundation can cause flipping of the blocks in first row of the protective coating that would result in its wrapping. This article presents the results of experimental research of hydraulic characteristics of water flow while flowing over two types of flexible concrete mats UGZBM-S and UGZBM placed crosswise the inward flow, that protect the pipeline. We’ve also determined the levels of free surface above differently buried pipeline crossings protected with two types of flexible concrete pavements under the conditions of stationary inward flow.
Influence of the drag coefficient on the maximum pressure of water hammer
Authors: Jonkobilov Ulugmurad , Jonkobilov Sobir , Tashmurza Yuldashev , Xoshiyev Shukhrat 
Published: January 2021

Abstract
The article presents the results of theoretical and experimental studies of the effect of hydraulic friction on the maximum increase in pressure during water hammer. To solve the problem of determining hydraulic friction along a pressure pipe, the telegraph equation was adopted as a mathematical model. As a result of solving the adopted equation, dependence is obtained for calculating the energy loss in a non-stationary process. The calculations of the proposed formula are in good agreement with the experimental data of the author. This proves the legitimacy of the obtained dependence of the author and provides an accurate calculation of pipes for strength during impact and resource saving of pipe material
Studying the hydrodynamic conditions of fluids in reservoir conditions and assessing their influence on the accumulation and placement of hydrocarbon deposits
Authors: Shoymuratov Tuychi , Yarboboyev Tulkin , Jurayev Fazliddin , Shodiyev Bobur 
Published: January 2021

Abstract
The article discusses the study of the behavior of reservoir fluids and the influence of the hydrodynamic situation on the accumulation and conservation of hydrocarbon deposits in the explored structures of the Beshkent trough. The main attention is paid to studying the value of the potential energy of fluids by mapping them at different points in the reservoir to determine the path of formation water and the possible hydrocarbon deposits associated with them. The places of their most probable accumulation are forecasted and recommendations are given for the implementation and adoption of optimal decisions on the targeted conduct of prospecting and exploration.
Strengthening technology and modeling of dams from reinforced soil
Authors: Glovatsky Oleg , Hamdamov B , Bekchanov Fakhriddin , Saparov Azamat 
Published: January 2021

Abstract
The aim of the work is to develop a methodology and technique for modeling reinforced soil for further use and application in hydraulic facilities to ensure their stable operation. The objectives of the study are to substantiate the efficiency of using dams of large canals made of reinforced soil at hydraulic structures of pumping stations of the Republic of Uzbekistan, taking into account local conditions, developing recommendations for the rational design of retaining walls and dams from reinforced soil. To achieve this goal, it is necessary to solve the problems of coordinating the operating modes of the pumping station with the introduction of retaining walls and dams from reinforced soil on full-scale structures. The article discusses the implementation of the method of building them in the management of water distribution on irrigation systems in Bukhara and Kashkadarya regions. The theoretical foundations of modeling and design of test stands for the study of volumetric models of dams of large channels made of reinforced soil have been developed. Studies on volumetric models of dams made of reinforced soil were carried out in compliance with the criteria of approximate similarity, which made it possible to obtain new physical ideas about the operation of structures at the stage of destruction. The conducted studies of the models of the built-up part of the dams made it possible to estimate the bearing capacity by the value of the breaking load of the reinforced model to the value of the breaking load of the unreinforced (reference) model.
The presence of reinforcement in the soil increases the bearing capacity of the model in comparison with the unreinforced one: even with the volume percentage of reinforcement μ = 0.064%, the hardening coefficient is equal to Chard = 2.60; with μ = 0.032% Chard = 1.70-2.07. With the same percentage of reinforcement μ = 0.032%, an increase in the vertical spacing of the reinforcement leads to a decrease in the bearing capacity by 12-15%. A more even arrangement of reinforcing elements in the ground (close vertical and horizontal spacing between them Sh ≈ Sv
) ensures the maximum bearing capacity of a reinforced soil structure.
Technology of water supply to water inlets of pumping stations
Authors: Ergashev Rustam , Ismoilov Naim , Nasirova Naira , Kholbutaev Boybek , Khusanbayeva Khusnora , Nazarov Odil 
Published: January 2021

Abstract
The aim of the research is to increase the efficiency of pumping stations operation by improving the methods of uniform spreading of the flow from the front chamber and the water intake of the pumping station and the development of constructive measures to improve the hydraulic conditions of the flow supply to the pumps. This goal is achieved by the fact that the device for supplying water to the water intake contains guiding elements. The improvement of the method of hydraulic calculation of the flow in the front chamber and the water intake chamber is carried out on the example of the head pumping station of the Jizzakh cascade. In the process of research, standard methods of full-scale and bench tests of pumps, methods of mathematical and hydraulic modeling, statistical processing of results and the creation of mathematical models based on the laws of hydromechanics were used.
The project substantiates the choice of a technical solution to improve the hydraulic structure of the flow in front of the impeller of the pumps of the Jizzakh head pumping station. The authors have developed new technical solutions, including an element for influencing the flow, installed in the water intake chamber of the pumps. This makes it possible to expand the ranges of stable, cavitation-free operation of the pump, to ensure an increase in the reliability of water supply to the pumping station, without resorting to complex and expensive reconstruction measures.
The quality of loosening the soil with subsoilers of the combined machine
Authors: Fayzullayev Kh , Mamatov S , Radjabov M , Sharipov Sh , Tavashov R , Nurmanova M 
Published: January 2021

Abstract
The aim of the study is to study the influence of the parameters of subs oilers on the quality of loosening of the soil when preparing the soil for sowing melons and gourds under a film with a combined machine. The authors have developed a combined machine for preparing the soil for sowing melons and gourds under a film. The structural diagram of the developed machine is presented. Theoretically, the completeness of loosening of the soil by subs oilers of the machine is determined from their parameters and relative position. Theoretical and experimental studies have established that the scheme of pair wise arrangement of subs oilers inclined to the right and left of the combined machine with working surfaces facing each other, as well as shifted relative to each other in the longitudinal plane, provides the required quality of work, while the longitudinal distance between the subs oilers should be 75 cm, and the transverse distance is 60 cm.
Cotton harvesters for one-time cotton-picking
Authors: Rizaev Anvar , Matchanov Rafik , Yuldashev A T , Kuldashev D A , Djuraeva N B , Karimov Nuriddin , Ashurov Nurali 
Published: January 2021

AbstractThe paper provides the study and substantiation of the parameters of semi-hitched spindle cotton harvesters during one-time cotton-picking. A calculation scheme for the spindle interaction with an open cotton boll in the “cylinder-deformable ball” form was proposed. A mathematical model to change the distance between oppositely located spindle drums in the working chamber and a method to calculate the indentation of the boll contact on the spindle of a vertical-spindle picking apparatus were obtained. The model made it possible to calculate the rational technological parameters of the device and machine. Kinematic functioning parameters of vertical-and horizontal-spindle picking devices were specified, taking into account their installation on a semi-hitched cotton harvester. The obtained data were used to create machines for a one-time cotton-picking.
Bench-scale study of centrifugal fan parameters
Authors: Rizaev Anvar , Malikov Zafar , Yuldashev Abdurakhim , Kuldoshev Davronbek , Temirov Djamaliddin , Borotov Atkham 
Published: January 2021

Abstract
The article is devoted to the development of a special simulation bench installation for studying the quality of the centrifugal fan used in the suction -blower pneumatic transport system of modern vertical -spindle cotton pickers. The principle of operation of a production structure of a pneumatic transport system with a lateral elliptical inlet of the fan casing is described based on a known technical solution. In order to determine the optimal location of the lateral elliptical suction channel of the fan casing, a stand was created that includes a centrifugal fan mounted on a frame and receiving movement by means of a belt drive from an electric motor. Four different positions of the ellipsoidal inlet and one central side connection of the air intake to the fan casing were tested on the bench. Based on the experiments carried out using a given amount of transported cotton, the performance of the fan was determined with the least damage to the seeds.
Synthesis of submicron-sized carbon-doped TiO2 for photodegradation of formaldehyde from wood-based panels
Authors: Luo Ligang , Yao Weihui , Yuan Ronghui , Shi Wei , Jin Xiaohong , Hu Jianhua , Jiang Guojun 
Published: January 2021

Abstract
Carbon-doped TiO2 particles were prepared by hydrothermal treatments and characterised via field emission scanning electron microscopy, powder X-ray diffraction and X-ray photoelectron spectroscopy. The results show that carbon was successfully doped into the TiO2 structures. Photocatalytic reactions were further investigated in a simulated indoor environment, and the visible-light catalytic activity of the carbon-doped TiO2 was evaluated by monitoring the photodegradation of the formaldehyde from wood-based panels. A degradation rate of 90% in 70 min was obtained, which demonstrated high photocatalytic performance.
Ceramic proppants for hydraulic fracturing
Authors: Biryukova A A , Dzhienalyev T D , Panichkin A V 
Published: January 2021

Abstract
The purpose of the work is the development of ceramic proppants from serpentinites and red mud. The chemical and mineralogical composition of the raw material was studied. It has been established that the main mineral of serpentinites is serpentine, which is present in the form of fibrous chrysotile and lamellar antigorite. Red mud is represented by sodium aluminosilicates of various hydrated forms, silicon oxide and hematite. Structural-phase transformations of compositions based on serpentinite and red mud were studied in the heat treatment process. The proppant phase composition is represented by forsterite, clinoenstatite, spinel compounds and complex sodium aluminosilicates. Proppants of magnesia-silicate composition based on serpentinite and red mud have been obtained with the following properties: bulk density 1.59-1.61 g/cm3, fraction of crushed granules with a compressive load of 69 MPa no more than 22%, sphericity and roundness - 0.8, chemical resistance - 98%.
Research on the wear and life of copper tungsten alloy contacts of high voltage SF6 circuit breakers
Authors: Xu Chao , Huang Hai , Wang Ying , Shi Xingcai 
Published: January 2021

Abstract
Three phase short circuit and two phase short circuit grounding fault of power system have a significant influence on the electrical life of circuit breaker contact. In this paper, the mathematical model of each component is established by Power System Analysis Software Package (PSASP), and the simulation model is built to simulate the dynamic state of the circuit breaker after different short-circuit faults. The simulated result confirms that contact electrical wear quantity related to the type of short circuit fault and the position of short circuit point. The size of short circuit current will directly impact electrical wear quantity and electrical life of circuit breaker contact.