bluuebunny/crossref_metadata_2025 huggingface dataset:
Feasibility study on construction of highway tunnel with large cross section in red beds geology
Authors: Zhu Junhao , Luan Guitao , He Baobing , Wu Hao
Published: January 2021

This paper is based on the Shanchongqing Tunnel of Yishi Expressway in Yunnan Province and takes numerical simulation to analyze the feasibility of using the three-step method to construct a three-lane large section tunnel in red beds. Through the research, it is found that the maximum displacement and settlement of the vault is -10.72mm, and the uplift value of the tunnel invert is 9.49mm; the maximum horizontal displacement of the arch waist on the left is 11.03mm, and the minimum horizontal displacement of the arch on the right is -12.52mm; the top displacement settlement extreme value is -10.72mm, the uplift value of the tunnel invert is 9.49mm, the maximum horizontal displacement value of the left arch waist is 11.03mm, and the minimum horizontal displacement value of the right arch waist is -12.52mm; the maximum axis of the left tunnel anchor rod The force is 41.82Mpa, and the maximum axial force of the bolt support structure of the right hole is 43.72Mpa. Therefore, through empirical comparison, these values meet the stability requirements of the tunnel. Comprehensively, the three-step method is feasible in the excavation of large-section V-level surrounding rock in red geology.
Sub-model stress analysis for construction process of a metro crossing passage tunnel with shield machine
Authors: Li GangGang , Chen ZhenLei , Liu ChaoJie , Lin ZhiQiang
Published: January 2021

This paper aims to simulate and optimize the structure stress during the construction process of a metro crossing passage tunnel with shield machine. Taking the world first metro crossing passage tunnel with shield method at Ningbo Metro Line 3 as an example, a finite element analysis model is developed to simulate the construction process. To achieve accurate results in some key structural components local sub-model approach is applied for some of sub-structures. The results obtained from the present finite element analysis are found to match well with the strain test monitoring data of the concrete segments. The obtained results also show that the maximum stress occurs at the T-joint of the starting and receiving sections during the construction process. With the progress of the construction, the stress at the T-joint of the starting section is gradually reduced, while the stress at the T-joint of the receiving section is gradually increased. Consequently, an authentic, reliable and advanced simulation process is established, which could provide technical support for the optimization of the construction process of metro crossing passage tunnel.
Risk Assessment of the construction of metro stations with open cut method based on fuzzy comprehensive evaluation method
Authors: Li Xiaolong , Wan Rongqiang , Wu Bo , Meng Guowang , Chen Huihao
Published: January 2021

Due to the loose structure, high moisture content and easy liquefaction of the sandy land layer in the coastal area, the construction of subway station open excavation has a high safety risk. Taking the deep foundation pit of Yufengwei station of Guangzhou Metro Line 7 as an example, this paper adopts fuzzy comprehensive evaluation method to evaluate the construction risk of Guangzhou metro station with open excavation method in the coastal area. The results are accurate and reliable, which can provide a reference for similar projects.
Effect of cement and fluidized bed combustion ashes on properties of phosphogypsum composite cementitious materials
Authors: Ma Pengfei , Li Shuang , Cheng Baojun , Yu Baoying , Gao Yuxin
Published: January 2021

The effect of fluidized bed combustion ashes (FBC) and cement by monodoping and compound doping on the mechanical properties and water resistance of phosphogypsum composite cementitious materials was studied, and the mechanism was explored by SEM. The results showed that the cement and fluidized bed combustion ashes by monodoping have a negative effect on the compressive strength of phosphogypsum, but can effectively improve its softening coefficient. When cement and fluidized bed combustion ashes mixed together, the softening coefficient increased with the increase of cement from 0 to 10%. But the softening coefficient decreased with the increase of cement from 0 to 20%, however, the compressive strength increased. Through the ANOVA analysis, the optimal dosage of cement, fluidized bed combustion ashes and phosphogypsum was obtained. Through the SEM, the hydration products covered on the surface of gypsum crystal, increased the compactness of the hardened body.
Peculiarities of the images of microscroches during load testing for fatigue fracture
Authors: Akhmetkhanov R S
Published: January 2021

The paper investigates the features of changes in the fractal dimension of microsection images during load tests for fatigue life. For this, the methods of the theory of fractals were used - the assessment of the fractal dimension of the images of microsections at different stages of loading, and their multifractal spectra were also determined. It was found that before the destruction of the sample, the multifractal spectrum degenerates into a monofractal.
Determination of tribological characteristics of polymer materials
Authors: Biryukov V P , Prince A N
Published: January 2021

The paper presents the results of tribological tests of thermoplastic polyurethanes (TPU) and rubber based on nitrile butadiene rubber (BNR) on rigidly fixed silicon carbide and free abrasive. The influence of pressure and sliding speed on the coefficients of friction is shown. For Elastollan 1164, the coefficient of friction and mass loss were 0.2-0.3 and 0.028 g, which is 5-7 times lower than for BNR.
Effect of strain rate on strength of unidirectional CFRP
Authors: Dumansky A M , Alimov M A , Terekhin A V
Published: January 2021

An analysis of the anisotropy of failure stress envelopes for unidirectional carbon fiber reinforced plastic at different strain rates, including dynamic loading, is carried out. Based on the study of transverse compressive and share strengths, a peak of the failure stress envelopes is observed, which is described by using the parabolic function approximation. It is shown that with an increase in the strain rate, not only an increase in strength but also a shift of the peaks to the area of higher transverse compressive stresses are observed.
Multiscale modeling of damage and fracture of a composite overwrapped pressure vessel
Authors: Eremin N V
Published: January 2021

An approach to multiscale modeling of damage and fracture of a composite overwrapped pressure vessel based on experimental studies is presented. The proposed approach takes into account the interaction of mechanical properties and structural parameters of the composite material at each scale level and their joint interaction. A micromodel of the fracture of a composite material has been developed taking into account the structural features. Calculated mechanical and strength properties of unidirectional composite material are determined. A mesomodel of fracture of a layered composite material is presented for numerical three-point flexural tests. Experimental verification of the numerical mesomodel of straining and fracture of a layered composite material has been carried out. A comparative analysis of the experimental data and numerical modeling showed the quantitative and qualitative agreement of the results. A macromodel of damage and fracture of a composite overwrapped pressure vessel is presented. The diagrams of progressive damage in a composite shell depending on the mode of fracture are presented. An assessment of the strength of the vessel structure is given taking into account the initiation and evolution of damage in the composite shell.
Calculated and experimental diagnostics of the stress state of large-sized parts of the chemical industry machines and estimation of their longevity
Authors: Petrova I M , Filimonov M A
Published: January 2021

A series of model and full-scale strain-gauge studies of the stress-strain state (SSS) of a large compressor connecting rod has been carried out. A computational model for assessing SSS is proposed, and its satisfactory agreement with the obtained experimental results is shown. The results of the SSS assessment are used to predict the resource for various operating options.
The substantiation of the influence of asphalt resin paraffin oil residue on the asphalt concrete technology
Authors: Bisenov Kylyshbai , Tanzharikov Panabek , Sarabekova Ulbossyn , Kodar Erden , Abildaev Nurlan
Published: January 2021

Based on scientific research and experimental tests, it has been proved that solid waste from oil fields in the Kyzylorda region based on asphalt resin paraffin sediment (ARPS) is close and binding in its chemical composition to the main component of the asphalt-concrete mixture of the road surface. And the most effective method of disposal and neutralization of oil waste was chosen. In this article, it is proposed to develop an asphalt-concrete technology based on asphalt-resinous paraffin deposits. The issue of increasing the reserves of raw materials for the production of durable asphalt concrete and reducing the amount of oil-containing waste in the fields due to the sale of solid oil-containing waste will be considered. Based on the study, the composition of asphalt-resinous paraffin deposits was analyzed by IR spectroscopy. The infrared (IR) absorption spectrum was captured in the IR-Fourier spectrometer. The results of the study showed the suitability of asphalt-resinous paraffin deposits for use as organic binders to dense asphalt concrete of type «B» grade III for IV-V road climatic zones recommended for applying top layers of coating on roads of technical category IY.
Complete diagrams of strain under axial tension of steel-fiber reinforced concrete with different fiber types and content
Authors: Krasnovsky Rostislav , Kapustin Dmitriy , Korotkikh Dmitry , Efishov Luka
Published: January 2021

The work provides the results of experimental investigation of strain properties of steel-fiber reinforced concrete with high-strength cement-sand matrix and various content of fiber (up to 6% by volume). The work demonstrates influence of the type and content of steel fiber over changes of characteristics of complete diagrams of strain under axial tension. It shows that introduction of fiber gives elastic properties to the matrix that (properties) in a greater degree depend upon the type of fiber than upon percent of fiber reinforcement.
Principle of computer synthesis of network polymers possessing a specified interval of glass temperatures
Authors: Askadskii Andrey , Zhdanova Tatyana , Matseevich Tatyana
Published: January 2021

For the first time, the model and the principle of constructing a corresponding computer program for the electronic synthesis of polymer networks with a given glass transition temperature range have been proposed. A repeating network fragment is synthesized from the smallest basic fragments that are connected to each other using a steering matrix of interactions. As an example, 10 cross-linked points, 16 basic fragments for constructing inter cross-linked chains and 5 repeating fragments of polymer networks are presented, the glass transition temperatures of which are within the specified range from 450 to 480K.
Seismic resistance estimation of existing turbogenerator foundation structures under ductility level earthquake impact by nonlinear static method
Authors: Zubritskiy Maksim , Ushakov Oleg , Sabitov Linar , Bambulevich Maksim , Akhtyamova Leysan
Published: January 2021

The article considers the multimodal nonlinear static method as a seismic resistance estimation method of existing turbogenerator foundation structures. The object of research is the turbogenerator foundation on the Tom-Usinsk State District Power Station. The article proposes a modified algorithm for the characteristic point search by the nonlinear static method. According to the calculations results, the existing foundation structures after a partial equipment replacement and the construction site increased seismicity are operational.
Studying the influence of taking into account the elastic-plastic behavior of strut elements on the retaining system equilibrium
Authors: Ter-Martirosyan Armen , Sidorov Vitalii
Published: January 2021

Currently, there is a rapid compaction of urban areas, which inevitably leads to the need for more active and integrated use of the underground space. In conditions of dense urban development, for the construction of underground structures or underground parts of buildings, it is necessary to design and realize deep excavations with vertical walls under the protective of the retaining structures, including supporting systems. The most common support is a system of metal elements -distribution beams and pipes (struts). The article deals with the calculation of the real excavations, taking into account the elastic and elastoplastic behavior of the support elements, the influence of this factor on the resulting internal forces and the stability of entire retaining system. Questions about the correctness of calculations by elastic models for structural elements used in geotechnics, are raised.
The influence of the human factor on the safety of operation of the industrial buildings and structures
Authors: Gvozdev Evgeniy
Published: January 2021

The article examines the results of the determining the indicator of the influence of the human factor on the safety of operation of industrial buildings and structures, their reliability to ensure the technological process. The purpose of the study is to provide a rationale for the occurrence of failures in the functioning of physical objects, after defects, which are associated with the human factor. To determine the indicators of the influence of the human factor on the safety of the operation of the buildings and structures, it is proposed to assess the risks not only taking into account technical factors, but also to supplement the scenarios of the occurrence and implementation of events associated with the human factor, shortcomings committed at various levels of the organization of public administration. To solve the problem, it is proposed to use the parameterization of the dependencies between the indicators of the occurrence of emergency events based on the human factor to the total number of all events that have occurred. The consistent theoretical description of the formulas is presented, which makes it possible to establish a relationship between the safety margin of the buildings and structures, the probability of its destruction under the realized influences associated with the human factor. The innovative approach is described, indicating the need to integrate the errors of the personnel operating the facility into the overall structure of risk assessment.
Analysis of the seismic stability of foundations according to laboratory soil tests
Authors: Ter-Martirosyan Armen , Sobolev Evgeny
Published: January 2021

Seismically hazardous areas are widespread on the territory of Russia. These are the North Caucasus, Altai, Sayan, Eastern Siberia, Kamchatka, Sakhalin. The issues of earthquake-resistant construction in difficult engineering and geological conditions, design in new earthquake-prone zones and construction in already developed territories are important aspects of the increasing intensity of development. Against this background, the problem of assessing the dynamic stability of soils becomes a priority task of modern soil dynamics and geotechnics. The article focuses on highlighting the main stages of the analysis of the dynamic stability of the foundations of structures of increased responsibility, taking into account complex geological conditions. The work contains the theoretical foundations of the methodology for assessing stability under dynamic loads, a description of laboratory equipment and test methods, the process of processing the experimental results. The study uses the results of assessing the dynamic stability of foundations obtained in the course of practical activities of the Scientific and Educational Center “Geotechnics” of the Moscow State University of Civil Engineering..
Polyspast -personal fall protection equipment. Features of certification and certification tests
Authors: Zherdev Kirill , Korolchenko Olga , Gadzhiyev Ragim
Published: January 2021

In the paper there was considered polyspast system as a means of personal protective equipment against falling from height. The structural place of these products in the classification of protective equipment, their functional purpose in ensuring the safety of work at height is analysed. The issue of statistics of accidents at work at height is touched upon. The relevance of the issue of continuous work on safety in this sector of work is shown. There are similarities in the need for safety and rescue operations in both the sports and industrial sectors. The purpose of this work is to form competent recommendations on various aspects of certification and certification tests of polyspasts to improve the safety of users, athletes (including children) and rescuers when performing various tasks and work at height. Within the framework of this work, the procedures for forming technical requirements for certified products, the totality of interaction of the main technical requirements of the technical regulations with the lists of standards specified in the Appendix to the technical regulations are considered. The analysis of two examples of polyspasts, certified in the market of the Eurasian Customs Union. The weak points of their certification due to the problems of the normative and technical state of the main documents in this area are shown. The conclusions provide a brief analysis of the problems of certification and certification testing of polyspast systems. Recommendations of both structural and local nature are formulated to improve the safety of certified products.
Reinforcement of brick partitions of buildings located in seismic areas with composite materials based on carbon fibers
Authors: Kabantsev Oleg , Simakov Oleg
Published: January 2021

Brick masonry is one of the most commonly used materials for creating internal partitions of buildings, including those located in seismic areas. The codes of a number of countries, including Russia, prescribe design requirements for strengthening partitions with external discrete steel reinforcement. At the same time, this solution is both labor-intensive in the production of works, and increases the seismic load on the partition (increasing the mass of the partition). This article explores the option of replacing the steel external reinforcement of partitions with composite roll materials – grids and tapes on an epoxy basis. The analysis of the strength values obtained in the course of experimental studies is carried out, and the result of calculations of the load-bearing capacity of characteristic partitions of real buildings with and without external reinforcement is given.
Finite element analysis of a frame connection of a girder with a rack under beyond design basis impact
Authors: Chernykhovsky Boris , Evtushenko Sergej , Alekseeva Anastasia
Published: January 2021

Over the past decade, the number of accidents in steel-framed buildings has been decreasing thanks to advanced approaches to cause analysis. In the presented article, a brief overview of the existing common design solutions of frame joints of the rack with the crossbar is made. A finite element design model of the structure under consideration has been made in accordance with the most common design solutions based on the experience of designing construction design organizations. The analysis of the local buckling of a steel structure element, which had cases of collapse in real life, was carried out. The results of the structural analysis of the structure without the presence of any defects were assessed, and the dependence of the bearing capacity of the structure on the presence of defects and the degree of their development was presented in a graphical form. The presence of a sensitive parameter of the structure under study was determined and the direction of further research of the frame connection of the rack with the girder was determined.
Assessment of translate-ability of “green” standards requirements into a machine-readable format for automated verification
Authors: Rybakova Angelina , Makisha Elena
Published: January 2021

Application of BIM methods gradually extends to all stages of life cycle of construction object, including the stage of expert review when compliance to mandatory state standards is evaluated. Moreover, there have been recently recommendations established related to the environment impact of a construction object, or so-called “green” standards. Their wide implementation requires verification of information models not only for compliance with mandatory state standards, but also to recommend “green” standards in the framework of certification. A necessary condition for organizing this process is the translation of the relevant requirements of the “green” standards into a machine-readable format. In this viewpoint, it is important to assess this possibility and develop corresponding approaches. The purpose of this study was to assess the requirements of existing “green” rating systems for the ability to translate into a machine-readable format for further automated verification of information models. To achieve this goal, an analysis of existing “green” certification systems was performed. As a result, according to a set of criteria, the “green” systems were identified, the translation of the requirements of which is appropriate and promising. For these standards, the possibility of translating their requirements into a machine-readable format was evaluated and recommendations were made to improve it.
Determination of the amount of internal heat input in the office space
Authors: Frolova Anastasia
Published: January 2021

A feature of office buildings is the presence in them of constant internal heat inputs during working hours, which, in accordance with the current standards for thermal protection of buildings [1], are not taken into account when determining the required value of the heat transfer resistance of the building envelope. However, they perform an important role in the choice of thermal protection of a building and directly affect the energy consumption of systems for maintaining the internal microclimate of premises [2-20]. The purpose of this study is to confirm the presence of internal heat gains (technological and household) during the day and year at a level close to the studied level [2-4] and the correctness of maintaining a given temperature regime in office premises, in which internal heat gains are known during the working day.
Determination of stiffness parameters of reinforced concrete structures using the decomposition method for calculating their survivability
Authors: Fedorova Nataliya , Kolchunov Vitaliy , Tuyen Vu Ngoc , Iliushchenko Tatyana
Published: January 2021

A method for determining the generalized stiffness of reinforced concrete structural systems of monolithic buildings using the decomposition method is presented. The secondary calculated scheme for determining dynamic additional loading in the frame of a monolithic building is adopted in the form of a substructure isolated from the frame of a building in the zone of possible local failure under a special action. For such a system, generalized stiffnesses are defined, depending on the angular stiffness of the support restraints and the stiffness of the overlying floors (adjacent structural elements). Analytical dependencies and a method for determining the overall stiffness of reinforced concrete substructures with specified boundary conditions are proposed. The influence of boundary conditions on internal force factors of the substructure is investigated. Recommendations are given for improving the survivability of the considered structural systems of monolithic buildings, as well as suggestions for their protection from progressive collapse.
Seismic responses of multi-story building isolated by Lead-Rubber Bearings considering effects of the vertical stiffness and buckling behaviors
Authors: Nguyen Van-Tu , Nguyen Xuan-Dai
Published: January 2021

Elastomeric isolation bearing is one of the most commonly efficient devices and widely applied for protecting constructions in the earthquake regions. Its significant lateral deformation during operation, however, may affect its load-carrying capacity, especially the stability of the bearing. The current preliminary design method often focuses on shear behavior without effects of vertical stiffness and stability conditions that do not reflect the practical operation of devices. The paper presents the effect of vertical stiffness and buckling behavior on the seismic performance of lead-rubber bearing (LRB) used for seismic isolation in multi-story buildings. The effective parameters of LRB are estimated by the single-mode spectral analysis method, through a bilinear model, calculated by a typical target spectrum of Eurocode 8. A two-spring equivalent model is employed to study the effects of the vertical stiffness and critical buckling load that is varied as a function of lateral deformation. A set of time history nonlinear analysis is conducted to investigate the effects of vertical stiffness and critical buckling load on the seismic responses of building structures. The findings show the taking into account of the vertical stiffness and buckling behavior results in an increase of lateral displacements and a decrease of the lateral force and the floor acceleration of the isolated building.
Determination seismic effect of buildings and structures, taking into account changes model of external relations within the life cycle
Authors: Kabantsev Oleg , Sergeev Evgeny
Published: January 2021

This research paper discusses the problem of the strain state formation in the bearing system through its lifespan. It is demonstrated that in the general case the seismic events (being quite rare natural acts) can impact the structures which, by the time an earthquake hits, will experience strains developed during the period preceding the earthquake. Consequently, the accurate seismic load calculation for the bearing system in view of the seismic events shall account for the strain state developed in the structures prior to the seismic event. Analysis of the customary computational techniques used in seismic load calculations for bearing systems and employing the response spectrum method reveals, that in the context of a single-stage calculation method it is possible to introduce only one model of external relations that corresponds to either the long-term loading effect or to the short-term seismic loads. Such approach is not aligned with the true-life pattern of external relations, which is subject to changes through the life span. For the purposes of accurate prediction of seismic response in buildings, it is proposed to use a multistage calculation method with the stage-to-stage inheritance of the stress-strain state. At that, at any stage it is possible to modify the properties of external relations. Compared are the calculation results of the seismic impact test model employing the customary calculation techniques and the multistage calculation method with adjustment of the external relations model to correspond with the lifespan mode. The outcome of the research proves that the use of the customary single-stage calculation method leads to significant simplification of the bearing system strain model, as well as to inaccuracy of the seismic response prediction result. Based on the research outcome, the single-stage calculation method is advised. It permits to take into account developments in the external relations model through the building lifespan.
Transverse vibrations of an underground cylindrical structure
Authors: Abduvaliev A , Abdulkhayzoda A
Published: January 2021

The transverse vibrations of an extended cylindrical underground structure under the action of concentrated forces changing according to a harmonic law are considered. The problem of transverse vibrations of a cylindrical rod interacting with an elastic homogeneous medium was solved by the Fourier method. Approximate solutions are obtained using the method of compensating loads. The influence of soil conditions and geometrical dimensions of the structure, the location of active forces on the amplitude-frequency characteristics of the object are analyzed.
Express-method of determining the water-yielding capacity of natural water sludge in modern dewatering technologies
Authors: Ryltseva Yuliya
Published: January 2021

Water treatment of surface sources for the purposes of public water service provision is impossible without waste build-up – sludge of water treatment plants. This kind of waste poses a considerable threat to the environment as it represents a complex organomineral structure with a high concentration of chemical reagents used for source water clarification and decolourization. In the present day, it is still international practice to discharge wastewater into surface water objects or onto the land surface, which causes severe damage to the natural environment. A tightening of environmental regulations encourages housing and utility services sector to undertake measures related to waste processing (waste dewatering). To implement these purposes mechanical machines (centrifuges, decanting tanks, filter presses, vacuum filters) are widely applied. An initial sludge quality, more particularly a filterability indicator – specific resistance to filtration – is a critical factor for the successful functioning of these machines. The higher the specific resistance to filtration, the worse the sludge gives away moisture, the more reagents and (or) mineral additives should be used before sending sludge for dewatering. Determining indicator of specific resistance to filtration using standard methods is quite a long process requiring the use of laboratory equipment. In this article, the author proposes an express-method enabling to determine within a short time span the water-yielding capacity of sludge based on the capillary suction speed of filtrate, standing out from its components. This method allows simplifying the start-up and commissioning of the modern sludge dewatering equipment as well as operation on the whole.
Planning organization of facilities for the municipal solid waste processing for use in the structure of small cities of Russia
Authors: Finogenov A
Published: January 2021

The range of problems, related to the environmentally dangerous accumulation of solid domestic waste (SDW) in Russian cities and settlements and the lack of effective ways of handling them, has been analyzed. The importance of this problem is substantiated for the difficult location conditions of geographically remote small towns and settlements of Russia, where the rational solution for solid waste collection conditions, transportation and processing still has not been found. The planning organization concept for small cities with the inclusion in their structure a modern system of objects for processing solid waste is proposed. A new methodological approach to the formation of functionally completed and environmentally friendly small residential agglomerations in the Russian regions is substantiated. The proposed methodology is focused on the use of advanced native technologies, using domestic waste as a renewable source of fuel for the production of electric and thermal energy. The new methodological approach is based on the complete exclusion of domestic waste landfill disposal in small towns in Russia and provides an effective scheme for waste collecting, advance preparation and container delivery for it complex processing with extensive use of the local railway transport network. The results of the study allow us to identify new directions in the field of small towns design and development in Russia, in relation to the requirements of a sustainable ecological environment ensuring.
Axisymmetric turbulent methane jet propagation in a wake air flow under combustion at a finite velocity
Authors: Hamdamov Muzaffar , Khujaev Ismatulla , Bazarov Orifjan , Isabaev Kasimbek
Published: January 2021

This article proposes a numerical method for solving the problem of an axisymmetric methane jet propagation in an infinite wake air flow. The dimensionless equations of the turbulent boundary layer of reacting gases in von Mises coordinates and the k-e turbulence model were used in modeling. The equations for N components of the gas mixture were reduced to two equations by introducing the Schwab-Zeldovich functions. To solve the problem in von Mises coordinates, a two-layer, six-point implicit finite-difference scheme was used, which provided the second order of accuracy of the approximation in coordinates. An iterative process was realized due to the nonlinearity of the equations for the conservation and transfer of substances. The effect of the radius of fuel nozzle on the indices of turbulent jet and flame was investigated. It was found that in an infinite wake flow of fuel with a decrease in the nozzle radius, the rate of chemical reaction and the highest temperature in the calculation area decrease, and the amount of unburnt fuel increases.
Recycling of municipal solid waste using solar energy
Authors: Toshmamatov Bobir , Davlonov Khayrullo , Rakhmatov Obid , Toshboev Abdumalik
Published: January 2021

The article proposes a solar installation for thermal processing of municipal solid waste and presents a method of technical and economic analysis of systems for processing municipal solid waste based on solar energy. The object of the research is a solar installation for thermal processing of municipal solid waste. The analysis of the heat balance of the developed solar installation was compiled and carried out, and the energy requirement for thermal processing of municipal solid waste was determined. The work uses the methods of the theory of heat and mass transfer and body balances of heat power and solar installations. The created solar installation for anaerobic fermentation of solid waste to obtain landfill gas and bio fertilizers has been investigated. Balance methods of numerical and experimental studies of anaerobic fermentation of solid waste were used to analyze the results. A calculation has been made showing the energy efficiency of a solar installation for the processing of municipal solid waste using solar energy. Based on the research carried out, it was found that at an average heating temperature of 50-55 °C, 200-250 m3 of landfill gas was obtained from one ton of household waste.
Maintainability of a self-pressurized closed irrigation network
Authors: Rahmatov Mahmud , Matyakubov Bakhtiyar , Berdiev Mustafo
Published: January 2021

This article presents the issues of maintainability of a self-pressurized closed irrigation network, which is one of the main most important characteristics of their reliability. The indicators of maintainability have been determined, the patterns of distribution of the time to restore the network operability have been established, bottlenecks have been identified during repair and restoration work. The obtained data is recommended for use in predicting the operability and developing regulatory requirements for network reliability.
Prospects for the development of Central Asia energy-deficient regions applying renewable energy and digital technology
Authors: Elistratov Viktor , Bogun Inna , Kasina Valeriia
Published: January 2021

The object of research in the article is the methodology for digital design of renewable energy facilities of Central Asia energy-deficient regions. This methodology is based on the creation of multi-layer geo-information space. Each layer of this space is an information map, containing necessary data for the design and implementation of renewable energy facilities for the development of energy-deficient regions. Designing map layers takes different approaches, depending on the type of information needed. In Central Asia as well as in the global energy industry is undergoing an energy transition and a regulatory policy for renewable energy in the electricity sector is being implemented, but introduced renewable capacities are connected to centralized power supply and do not currently contribute to the development of remote areas. Taking into account the availability of sufficient renewable energy resources technical capacity, a reasonable solution is the introduction of renewables generating facilities. This allows improving energy efficiency by reducing losses during transmission and distribution of electricity due to proximity to the consumers and improving the environmental situation in energy-deficient settlements by decreasing harmful emissions. Potential analysis confirms the possibility of implementing an energy strategy with the prospect of developing renewable energy projects in Central Asian countries.
Simulation of criteria for selection of remote protection settings with remote starting in lines with distributed sources
Authors: Voloshyn Semen , Omelchuk Anatolii , Tarasiuk Oleh , Titova Liudmyla , Gumenyuk Yuriy
Published: January 2021

The article presents the conditions of coordination of adjacent remote protections with remote start-up, considering the peculiarities of parameters, operating modes and operating conditions of partitioned branched distribution lines. The influence of parameters and modes of operation of such lines on the technical characteristics of these protections, in particular, on the range of control settings for resistance and operating time at the end of the range and the requirements for the linearity of time characteristics. It is recommended to use the results of the conducted research for adjustment of remote protections of partitioned lines with sources of distributed generation. In order to ensure the selective action of protection in different modes of operation of the lines and the convenience of choosing the settings of operation, the time characteristic of the protection must be linear. In addition, the linearity of the protection time characteristic allows the operation time value to be used to determine the distance to the short circuit location. Due to the need to debug the protection by the time of operation from the operation of the arresters and from burnout of the fusible insert fuses soldering in the event of a short circuit directly behind the fuse, the initial duration of protection should be 0.25…0.40 s.
Preparation of N, N-dialkyl quaternary ammonium chitosan and its long-lasting antibacterial finishing process for rabbit fur fabric
Authors: Jiang Yingxue , Zhang Yi , Zhang Hao
Published: January 2021

N,N-dialkylchitosan (N,N-CTS) was modified by n-butyraldehyde using Schiff base method, it is then synthesized with N,N-CTS by etherification with 3-chloro-2-hydroxypropyltriethylammonium chloride (CHPTAC-ethyl). FTIR and spectrophotometry were used to characterize their chemical structure and physical and chemical properties. The minimum antibacterial activity of the modified chitosan was determined by the minimum bacteriostatic method, and the minimum effective bacteriostatic concentration (MIC) of Escherichia coli was 0.2 g/L, which was better than that of natural chitosan. The antibacterial effect and washing resistance of rabbit wool fabric were investigated by using modified chitosan. After washing for 10 times, the results showed that the inhibition rate of N,N-CCTS on escherichia coli was still more than 99.9%.
Marine based biomaterial-fish collagen enhances the polarization of human macrophage
Authors: Liu Chao , Sun Jiao
Published: January 2021

Fish collagen have the potential to be used in biomedical fields due to the biocompatible and biodegradable features. However, how hydrolyzed fish collagen regulate human macrophage has not been clearly unraveled. The aim of the current study is to investigate the effects of hydrolyzed fish collagen on the polarization state of human macrophages. The cell viability of human macrophages treated by hydrolyzed fish collagen were determined using CCK-8 assay. The polarization of human macrophages treated by hydrolyzed fish collagen were detected by quantitative real-time polymerase chain reaction (qRT-PCR). it was found that 0.25,0.5 and 1mg/ml hydrolyzed fish collagen did not alter the cell viability of human macrophages. Further, the data showed that hydrolyzed fish collagen inhibited the expression of M1 macrophage marker IL-ip and TNF-a while enhanced the expression of M2 macrophage marker arginase 1(Arg1) and IL-10. Taken together, the results indicated that treatment with hydrolyzed fish collagen result in a significant shift towards an M2 phenotype for human macrophages.
Corrosion behavior of C-22, Ti-0.2Pd and Ti-32Mo alloys in the aqueous solution of hydrochloric acid and sodium chlorate
Authors: Zhang Mingyue , Ma Bingqing , Xu Jian , Zhou Huangwei , Liu Yi , Chen Zhibing , Xu Ziwei , Chen Jia , Ye Jiafan
Published: January 2021

Corrosion behavior of Hastelloy C-22, Ti-0.2Pd and Ti-32Mo alloys in the aqueous solution of hydrochloric acid and sodium chlorate was investigated. The C-22 alloy was pitted because the intergranular carbides rich in Cr and Mo would lead to the lack of corrosion-resistant elements in the adjacent area. The Ti-0.2Pd alloy was pitted because the passivation trend decreased in reducing solution and Cl− broke through the passivation film. The weigh loss rate and corrosion depth of Ti-0.2Pd alloy increased sharply after pitting corrosion, which was due to the rapid corrosion of the materials exposed inside by the corrosion medium. The Ti-32Mo alloy was pitted due to the transpassivation of Mo caused by NaClO3. In the process of corrosion, the products of reaction between Mo and Cl− formed an insoluble and dense protective film, which slowed down the corrosion rate of Ti-32Mo, that is why the weigh loss rate and corrosion depth increased slowly even if pitting corrosion happened.
Thermal deformation behavior of Stellite 6B alloy
Authors: Yawei Zhang , Shixiao Zhang , Xudong Lu
Published: January 2021

Stellite 6B is carbide-hardened Co-based superalloy. It finds extensive application in the harsh industrial environment, because of excellent wear characteristics, high hardness, good corrosion resistance, and superior mechanical properties. Hot compression tests were performed on Stellite 6B alloy to study high temperature dynamic recrystallization and microstructure evolution during thermal deformation. The tests were performed in the temperature 1000 °C, 1050 °C, 1100 °C, 1150 °C and 1200 °C and at the strain rates of 0.01 s−1, 0.1 s−1, 1 s −1 and 10 s−1. Stress-strain curves, and the microstructural evolution of the Stellite 6B alloy were investigated. The results showed that the recrystallization was nucleated at the carbides, original grain boundaries and twin grain boundaries, the dynamic recovery process is inhibited, and the softening effect by dynamic recrystallization is more significant.
Potential of limestone powder to improve the stabilization of sulfate-contained saline soil
Authors: Bazarbekova Ayazhan , Shon Chang-Seon , Kissambinova Aizhan , Ryeol Kim Jong , Zhang Dichuan , Moon Sung-Woo
Published: January 2021

The geotechnical properties of soils differ from area to area, depending on the origin of soil, environmental conditions of a region, and soil treatment processes. As a subgrade material in pavement construction, however, the soil is required to meet specific standards for its engineering properties, such as plasticity, deformability, strength, and durability parameters. For this purpose, soil undergoes a stabilization process, in which it is treated with chemical additives. This paper studies the potential of limestone powder as a stabilizer in combination with cement in the stabilization of sulfate-contained saline soil. For this purpose, silty sand (A-2-4(0) according to AASHTO soil classification system) containing high sulfate and sodium contents was stabilized with 6% and 8% cement by dry weight, 2% and 4% limestone powder at fixed 4% cement content, and 2% limestone powder by dry weight at 6% cement content. Series of tests were performed to determine the improvement of geotechnical properties of these mixtures, such as unconfined compressive strength, Atterberg limits, three-dimensional (3-D) swelling, and dielectric constant. Experimental results show that the addition of limestone powder to the cement-treated saline soil decreases soil plasticity, increases maximum dry density, improves strength parameter, reduces volumetric swelling and moisture susceptibily of soil.
Beyond Standardization: Improving External Validity and Reproducibility in Experimental Evolution
Authors: Desjardins Eric , Kurtz Joachim , Kranke Nina , Lindeza Ana , Richter S Helene
Published: January 2021

Discussions of reproducibility are casting doubts on the credibility of experimental outcomes in the life sciences. Although experimental evolution is not typically included in these discussions, this field is also subject to low reproducibility, partly because of the inherent contingencies affecting the evolutionary process. A received view in experimental studies more generally is that standardization (i.e., rigorous homogenization of experimental conditions) is a solution to some issues of significance and internal validity. However, this solution hides several difficulties, including a reduction of external validity and reproducibility. After explaining the meaning of these two notions in the context of experimental evolution, we import from the fields of animal research and ecology and suggests that systematic heterogenization of experimental factors could prove a promising alternative. We also incorporate into our analysis some philosophical reflections on the nature and diversity of research objectives in experimental evolution.
Phylogenetic analysis of Microlicieae (Melastomataceae), with emphasis on the re-circumscription of the large genusMicrolicia
Authors: Versiane Ana Flávia Alves , Romero Rosana , Reginato Marcelo , Welker Cassiano A Dorneles , Michelangeli Fabián A , Goldenberg Renato
Published: January 2021

Microlicieae are a monophyletic tribe comprising seven genera: Chaetostoma, Lavoisiera, Microlicia s.s., Poteranthera, Rhynchanthera, Stenodon and Trembleya. Microlicia s.s. includes 172 species predominantly distributed in the campo rupestre of Brazil. Its delimitation is complex because the generic boundaries, mostly with Lavoisiera and Trembleya, are unclear. Here we present a phylogenetic analysis for Microlicieae focusing on Microlicia s.s., with the specific goals: (1) to test the monophyly of Microlicia s.s.; (2) to investigate morphological characters that could help in circumscribing clades and/or genera in the tribe and (3) to provide an appropriate classification for Microlicia s.s. and related genera. This study was based on plastid (atpF-atpH, trnS-trnG), nuclear ribosomal (nrITS, nrETS) and nuclear low-copy (waxy) DNA sequences, through maximum likelihood and Bayesian inference analyses. The history of 12 morphological characters was estimated based on ancestral state reconstruction analyses. Our analysis shows Microlicia s.s. to be paraphyletic with Chaetostoma, Lavoisiera, Stenodon and Trembleya nested in it. Most characters traditionally used to diagnose these genera are homoplastic. We propose the inclusion of these four genera in a broadly circumscribed Microlicia s.l., and provide new combinations and names for their species. As here defined, Microlicieae has three genera, Rhynchanthera, Poteranthera and Microlicia s.l., Microlicia s.l. being the fourth richest genus in Melastomataceae with c. 245 species.