bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of eccentricity on the strength characteristics of glued rods made of steel cable reinforcement in solid wood
Authors: Koshcheev A A , Roshchina S I , Naichuk A Y , Vatin N I 
Published: August 2020

Abstract
The article is devoted to the study of the behavior of glued rods made of hot-rolled steel reinforcement and steel cables in a solid wood based on experimental tests of beam elements. The influence of eccentricity on the deformation - strength characteristics is studied with a straight-line gluing of reinforcing rods. The comparative analysis of the deformability indices of the centered and lateral gluing performed by milling with fillet groove U - shaped milling cutters was carried out. The technology of manufacturing samples, which consists of preparing wood, milling and pasting rebar into the groove, were described. The diagrams of deformation - strength characteristics of samples of various types were obtained and correlated. The conclusions were drawn about a local increase in strength in the case of using a steel cable as reinforcement and the negative effect of eccentricity on the strength of the adhesive joint during tensile tests. A visual analysis of the damage occurring during the test showed that in the manufacture of full-scale structures, glued rods should be closed with an array of wood. The conclusions were drawn about the optimal depth of milling of grooves for reinforcement, taking into account the use of adhesive compositions on epoxy resin filled with quartz sand - 1.5 depth of reinforcing bar diameter.
Local deformation and strength characteristics of S-shaped reinforcement in wood
Authors: Koshcheev A A , Roshchina S I , Aleksiievets V , Labudin B V 
Published: August 2020

Abstract
Reinforced wooden beam structures under the influence of critical loads are subject to brittle fracture, which is dangerous when operating beams in buildings. To solve this problem, reinforcement of wooden beams for civil and industrial buildings was invented using steel rope as a reinforcing element. The rope is located in the stretched area of the beams along the original S-shaped trajectory. Numerical studies of the deformation of the reinforcement model using the LIRA program are performed. Based on numerical studies, samples were made for testing for pulling S-shaped anchoring elements from solid wood. The analysis of deformation - strength characteristics based on the results of tests on a tensile testing machine glued curved rods. A triple increase in the ductility of the deformation of the paste in the zone of destructive loads was revealed. The main problems of this type of reinforcement are the appearance of stress concentrators in areas with a small radius of curvature of the reinforcement. As a result of the study, the optimal trajectory of the reinforcement insert was determined with the aim of obtaining higher strength and deformation characteristics - with a reduced oscillation amplitude. The possibility of using structures in the form of safety elements has been established, which allows to increase the destruction time of beam systems when exceeding the permissible load.
Strength and deformability of lightweight metal trusses with elements from cut I-beams
Authors: Popova M , Sergeev M , Lukina A , Shunqi Mei 
Published: August 2020

Abstract
The article is devoted to the study of the strength and deformability of light metal trusses with elements made of cut I-beams based on experimental tests. A truss design is proposed based on the idea of a waste – free technology for obtaining the maximum number of truss elements in the process of cutting the initial billet-a rolling I-beam. The manufacturing technology of the farm, research tasks and test samples are described. The developed and manufactured designs of truss models were a geometric similarity of trusses with parallel belts with a span of 24 m, a cross – section height along the shelves of the belts-2.4 m, with the length of the belt panels equal to 3 m, calculated for different loads. The analysis of the obtained results showed that the theoretical values of axial stresses in the elements of truss models differ from the values of experimental axial stresses in General by no more than 8%. According to the results of numerical studies of the stress-strain state of trusses in the elastic stage of their operation, it was established: - truss structures have sufficient stiffness and strength (the coefficient of load-bearing capacity was a value that varies for trusses of various series within the range of 1.34 – 1.7); - the stress values in the truss elements calculated during the processing of the results of numerical studies have a large similarity with the stress values calculated on the basis of experimental data.
Stress-strain state of wooden beams with external reinforcement
Authors: Lukin M V , Roshchina S I , Gribanov A S , Naychuk A Ya 
Published: August 2020

Abstract
The stress-strain state of wood-composite beams was studied numerically. Numerical studies were performed on wood-composite floor beams with a cross-section size of 100×240 mm and a length of 4.8 m. it was Experimentally proved that the deformability of wood-glued beams is reduced by 1.8…2.1 times, compared to conventional wooden beams. For wooden beams in the elastic design stage, the limiter is the calculation of the 2nd group of limit States (for stiffness), for composite beams, the calculation of the 1st group of limit States (for strength. The calculation proved that the deformability of wood composite beams is reduced by 1.8…2.1 times, compared to conventional wooden beams. The high efficiency of the finite element method calculation for evaluating the criteria of load-bearing capacity of wood-composite beams up to their destruction is proved.
Wooden beams with local wood modification
Authors: Gribanov A S , Roshchina S I , Naichuk A Ya , Melekhov V I 
Published: August 2020

Abstract
The purpose of this work is to study the strength of wooden beam structures with local modification of wood in the compressed zone. To achieve this goal, the physical and mechanical characteristics of modified wood were determined using modifiers based on ed-20 epoxy-diane resin, urea-formaldehyde resin, and dimethacrylic polyester. The best physical and mechanical characteristics were obtained for samples using dimethacrylic polyester: the ultimate strength was 84 MPa, the elastic modulus was 21 GPa. The increase in strength compared to solid wood was 46%, and the increase in the modulus of elasticity was 54%. Tests of beam structures with a span of 4.5 m and a cross section of 100x200 mm with local modification of wood in the compressed zone with a polymer composition based on dimethacrylic polyester were carried out. The increase in the strength of beams with local modification in the compressed zone compared to solid wood was 11% within the design loads, and the increase in stiffness by 18%. The “load-strain” relationships are constructed based on the test results. It is established that the greatest effect can be achieved when using external reinforcement systems together in a stretched zone by reducing the influence of defects and defects in beam structures and local modification of the extremely stressed compressed zone.
Numerical study of filtration process of ground and pressure waters in multilayer porous media
Authors: Daliev Sherzod , Abdullaeva Barno , Kubyasev Kurash , Abdullaev Otabek 
Published: August 2020

Abstract
A article discusses the process of forecasting changes in the level of ground and pressure water. A brief analysis and computational experiments of scientific papers on mathematical and numerical modeling of the object under study are given. For a comprehensive study of the problem under consideration, a mathematical model was developed that takes into account the external source, evaporation, filtration coefficients, active porosity, filtration rate and two-way boundary conditions. An effective numerical algorithm has been developed for predicting changes in the ground water level using a combination of finite-difference schemes and run-through methods. It has been studied that changes in the level of ground and pressure water, filtration permeability, water loss coefficient and filtration rate associated with the water level can have a serious impact on the environmental process.
Mathematical modeling of a waterjet jet for structural material cutting
Authors: Shpilev Vasiliy , Reshetnikov Mikhaile , Borodulina Svetlana , Zakharchenko Mikhail , Ivashchenko Yuri 
Published: August 2020

Abstract
When modeling a jet during hydroabrasive processing of structural materials, we will represent it as a heterogeneous environment. And accordingly, the hydroabrasive flow will be considered as a heterogeneous flow. The equations describing the formation of a heterogeneous flow are based on the equation of conservation of momentum of the total movement and allow for the interaction of the background flow and particles of the abrasive. A mathematical model of a heterogeneous flow, reveals the mechanism of formation of a waterjet jet. Based on the mathematical model, the hydrodynamic forces and surface stresses acting between the abrasive and the liquid can be taken into account. It also takes into account speed, concentration, mass, density of the fluid and abrasive. Knowing these parameters, it is possible to use the mathematical model of a heterogeneous flow to find the optimal conditions for the formation of a waterjet flow and the processing of structural materials.
Man-made soils and mining wastes as raw materials for building composites
Authors: Zakrevskaya Lubov , Gavrilenko Andrei , Andreeva Ksenia , Lubin Petr , Kapush Ilya , Udin Igor 
Published: August 2020

Abstract
The crucial task up to date is to find effective solutions to expand the raw material base of the construction industry by involving local natural and man-made raw materials instead of traditional expensive energy-intensive materials. An inexhaustible source of raw materials can be mining waste, such as dolomite and lime. Currently, they are large-tonnage industrial deposits that limit the area of development. The problems of strengthening man-made cohesive soils for the manufacture of wall materials, and their use as natural bases is also front and center. The optimal compositions of soil-concrete mixtures based on waste carbonate deposits are selected. The goal of this work was to design a composition of a complex binder for strengthening clay soil. The second goal of the work was to obtain masonry soil-concrete products. For this purpose, waste from the dolomite production of the Melekhovsky deposit was used. To solve the problems, authors carried out such tests as chemical analysis, mineralogical analysis, X-ray phase analysis, raster electron microscopy, compressive strength test, frost resistance test, and water resistance test. Comparing the obtained results, it is now becoming apparent that the compositions of GD-4 and GD-5 at close density values have high strength characteristics at design age. The content of dolomite waste above 30% leads to an increase in strength, the best results are achieved with a dolomite content of 34.6-45.3%, in this range also with increasing binder content, water absorption and density increase, and therefore porosity decreases. The phosphates that make up the composite increase its water resistance.
A composite ceramic material for an abrasive tool
Authors: Bolotov A N , Novikov V V , Novikova O O 
Published: August 2020

Abstract
The paper describes the features of the electrochemical formation of a modern abrasive tool material. The technology for obtaining the material consists in obtaining a composite diamond-bearing ceramic layer on the surface of diamond-aluminum sintered blanks by microarc oxidation. It was established that the degree of diamond metallization with copper and the relative density of a sintered blank affects oxidation the most. It was impossible to obtain a composite ceramic material by microarc oxidation with diamonds coated with nanodispersed copper with a metallization degree of over 100%. The relative density of sintered blanks should be 80–90% to form a composite material with optimal physicomechanical and tribotechnical properties. Diamond concentration did not affect the creation of stable spark discharges that form aluminum oxide. The optimal alkali concentration in the electrolyte to reach the maximum thickness of the diamond-bearing composite material was about 2 g/l. Comparative tests showed that the wear resistance of a diamond-bearing composite material with a ceramic matrix based on aluminum oxide was notably higher than traditional analogues under similar friction conditions. Finally, the paper determines the scope of the obtained diamond-bearing ceramic material as a tool for precision processing of superhard materials in precision engineering, instrumentation engineering, and the medical industry.
Diagrams of concrete behavior over time
Authors: Varlamov A , Kostyuchenko Y , Rimshin V , Kurbatov V 
Published: August 2020

Abstract
The article presents a new vision of building diagrams of the work of materials in time. The main starting point is the law of conservation of energy of a closed system. The material is represented by an initial graph of the energy acceleration distribution. The external influence is represented as a rectangular form of energy acceleration distribution. At every moment of time, the external acceleration of energy exceeds the acceleration of the material’s energy. The obtained dependence of the material diagram is analyzed. Graphs of various forms of energy acceleration are obtained. Their summation shows the true diagram of the work of the material. Defining the characteristic points of the concrete behavior diagram, a true diagram of concrete behavior over time is constructed. By changing these characteristic points, we track the changing behavior of concrete over time.
Modification of bitumen for road construction
Authors: Provatorova Galina , Vikhrev Alexander 
Published: August 2020

Abstract
To increase reliability and durability of road surfaces, asphalt concrete based on modified bitumens is actively used. Experts’ research shows that in modified bitumen extracted from road surfaces after 10 years of operation there are no significant changes in viscosity. The purpose of this study is to improve the properties of bitumen and asphalt concrete based on it by modifying road bitumen with carbon nanotubes. Bitumen was modified with carbon nano-tubes obtained by deposition from the gas phase in the laboratory of Vladimir State University. The selection of the optimal amount of the introduced modifier was performed, modified bitu-men was prepared, its properties were determined, and a comparative analysis of the properties of asphalt concrete made on modified and non-modified bitumen was carried out. Due to the introduction of carbon nanotubes into the heated bitumen, the strength and elasticity of the resulting asphalt concrete are significantly increased. The test results showed an improvement in all quality indicators of asphalt concrete by 7-9%, which allows us to say that the resulting composite has increased strength characteristics.
Influence of presteaming period and curing temperature on the plasticized concrete strength
Authors: Leshkanov Andrei , Dobshits Lev , Anisimov Sergey 
Published: August 2020

AbstractHeat-moisture treatment (HMT) is the main way to speed up the strength of reinforced concrete products. But this technology is the cause of high energy and resource costs. The use of traditional plasticizing additives in concrete is difficult in terms of early strength reduction. The modern industry of chemical additives allows regulating superplasticizers (SP) molecular structure. The use of such modifiers in concrete leads to early strength increase. The combination of HMT and SP using in concrete hardening makes the optimization of steaming parameters possible. HMT variable modes of concrete modified with polycarboxylate SP were investigated for early strength. The stripping concrete strength with an increase in SP dosage from 0.4 % to 2.0 % by cement mass decreases as follows: at the maximum curing temperature of 40 °C – on 32.8 %; at the temperature of 60 °C – on 27.2 %, at the temperature of 80 °C – on 23.8 %. The concrete compressive strength after HMT without the presteaming period is lower by only 5.4-14.3 % in comparison with concrete steamed with one for 1-2 hours. The research was carried out on concrete using sand with a low size modulus of 1.70. The authors show the superplasticizer effectiveness in terms of reducing the water-cement ratio and joint action with HMT. Mathematical models of the early concrete strength were obtained depending on curing temperature, presteaming period duration, and the SP dosage. The obtained results can be used in the reinforced concrete products production, subject to additional research.
Effect of superplasticizer and silica fume on the properties of self-compacting mortars
Authors: Smirnov A O , Dobshits L M , Anisimov S N 
Published: August 2020

Abstract
Self-compacting concrete is a highly flowing concrete that compact under self-weight without any vibration effort. The mortar phase of self-compacting concrete determines its rheological, strength characteristics, and durability. This paper discusses the effect of superplasticizer and silica fume on the properties of self-compacting mortars. Mini-slump flow diameter tests were conducted to determine the rheological properties of mortar mixtures, and compressive strength, density, water absorption, porosity experiments to assess the hardened properties of mortar specimens. Analysis of regression models shows that the use of superplasticizer reduces the water demand of mortar mixtures by up to 40 %, and the addition of silica fume leads to the densification of cement stone structure and reduces the porosity of concrete to 24 %. The maximum compressive strength at 2 days can be achieved with a superplasticizer content of 0.8-1.0 % and 0-5 % silica fume by binder weight, and at 28 days – with 1.0-1.2 % superplasticizer and 10-15 % silica fume content. According to X-ray phase analysis in a cement stone containing superplasticizer and silica fume, the degree of cement hydration increases and reduces the amount of portlandite, which leads to an increase in the strength and durability of the concrete.
The role of colmatation in liquid corrosion of hydrophobized concrete
Authors: Fedosov S V , Rumyantseva V E , Konovalova V S , Evsyakov A S 
Published: August 2020

Abstract
To reduce water absorption of cement concretes resort to hydrophobization by introducing special additives in the manufacturing process of the product. In the study of liquid corrosion of hydrophobized cement concretes of the W4, W6 and W8 waterproofness grades in media of various degrees of aggressiveness, the terms for achieving a state close to the equilibrium concentration of calcium cations in the solution were established. Based on the experimental data on the liquid corrosion of cement concretes of various grades in terms of water resistance, the optimum amount of hydrophobizing calcium stearate additive was determined, which is sufficient to prevent corrosion damage in concrete, depending on the degree of aggressiveness of the medium. Tests of strength characteristics of hydrophobized cement concretes of the W4, W6 and W8 waterproof grades were carried out. It is established that when alkali and alkaline-earth stearates are introduced into concrete as hydrophobic additives, its strength is significantly increased compared to non-hydrophobized concrete samples. Some special cases of changes in the mass conductivity coefficient during colmatation of hydrophobized cement concretes of the W4, W6 and W8 waterproof grades are considered and graphically illustrated. Profiles of changes in the rate of colmatation and the thickness of the colmatant layer for cement concretes with and without hydrophobizing additives are presented. The profiles show that over time there is a weakening of the mass flow, which is obviously associated with an increase in the colmatant layer. The rate of colmatation is also reduced due to the fact that the layer of colmatant partially or completely clogged the pores and prevents further penetration of the aggressive medium deep into the concrete.
Effect of laser radiation parameters on surface modification of critical engineering part
Authors: Abrakhin S I , Arakelian S M , Bukharov D N , Abrakhina S I , Evstyunin G A 
Published: August 2020

Abstract
In this work, computational experiments were carried out using the MatLab Laser ToolBox package to determine the power range of a radiation source for realizing nanomodification of the C45 grade steel surface without melting. The dependences of the sample maximum temperature are determined depending on the power of the laser radiation source, beam diameter, and scanning speed. It has been found that for a steel plate, a power of more than 3.7 kW in the case of a slowly moving source (10 mm/s) and more than 4.9 kW in the case of a fast-moving source (20 mm/s) are required for melting. Moreover, an increase in power of a slow source by 0.2-0.3 W is accompanied by an increase in the maximum temperature by 200 K at the beginning and will increase towards the end of the heating process, which goes into melting stage.
Examination of engine cylinder-piston group damages
Authors: Bazhenov Yu , Kirillov A , Bazhenov M 
Published: August 2020

Abstract
Results of investigations of engine cylinder-piston group (CPG) damages and causes of their occurrence are given. The object of the study is the KIA Ceed engine, which came for examination due to a significant decrease in power, increased consumption of motor oil, violation of the dynamics of the car. The analysis of the technical condition of the disassembled engine showed that the parts of the crank mechanism and the cylinder head have no operational damages. Serious damages were detected only in the cylinder-piston group of the engine: abrasive wear of the working surfaces of cylinders, pistons and compression rings, coking of oil removal rings, deposits on the surfaces of all pistons of the engine. According to the results of the studies, the cause of loss of efficiency by the engine is the destruction of the ceramic catalyst, the products of which in the form of ground powdered substance enter the cylinders together with the exhaust gases. This occurs at the moment of simultaneous opening of exhaust valves of two cylinders having different exhaust gas pressure. A small amount thereof, together with the catalyst breakage products, penetrates the lower pressure cylinder through the manifold. A study of the substance of deposits on the pistons of the engine and the destruction products of the elements of the ceramic catalyst (cordierite Al4Mg2O16Si5), carried out on the powder diffractometer BRUKER AXS, showed the identity of their diffraction composition. This indicates that damage to the parts of the CPG and loss of performance by the engine is caused by destruction of the ceramic catalyst.