bluuebunny/crossref_metadata_2025 huggingface dataset:
Prospect for the application of augmented and virtual reality technologies in the design, production, operation of aircraft and training of aviation personnel
Authors: Neretin E S , Kolokolnikov P A , Mitrofanov S Yu
Published: July 2021

Employees of the Department 703 MAI together with employees of Department 741.170 PJSC “Corporation “Irkut” carried out work on the analysis of possibilities of introduction of modern innovative technologies of augmented and virtual reality in the design, production, operation of aircraft and training of aviation personnel. In the course of work, prototypes of two virtual reality sets were developed. As part of the demonstration of the capabilities of augmented reality technology for solving the problems of aircraft operation and aviation personnel training, two mobile applications were developed. Approbation of the presented projects were carried out in MAI and PJSC “Corporation “Irkut”. The presented prototypes received the highest rating of the scientific and technical Council of PJSC “Corporation “Irkut”, and the interest in implementing such solutions in their production processes was confirmed by manufacturers of aircraft simulators (LLC NPF “SKT” represented by the chief designer), higher educational institutions (MSTU GA represented by the Vice-Rector for research and development), aircraft manufacturers (PJSC “Corporation “Irkut” represented by the Deputy head of the design and training methodology Department) and aircraft operators (PJSC “Aeroflot” represented by the Director of the aviation personnel training Department).
Adaptive algorithm for mobile robot movement control
Authors: Zhidkov V N
Published: July 2021

The paper reviews the goal of controlling mobile robot movement along the planned path. It proposes an adaptive robot movement control algorithm, allowing to increase the precision of holding the robot within the prescribed path under the conditions of unstable navigation field. The adaptation of the algorithm to jamming environment is in redistributing weights of the weighted sum of estimates given by the ultrasound navigation system (USNS) and wheel pulse transducers (WPT). When precision of the USNS reduces affect of the WPT on the final estimate increases while affect of the USNS decreases. Such a redistribution is carried out when the system is operating due to changing elements of a measurement noise matrix in Kalman filter [1] with use of which a mobile robot heading angle is estimated. Corresponding elements of the measurement noise matrix increase along with increase of deviation of the mobile robot trajectory from a straight line. The extent of deviation calculated as the standard error of a regression is defined by means of the statistical analyses involving the last n measurements contained in buffer store of the USNS. The obtained results demonstrate significant benefit of the developed mobile robot heading estimation algorithm in comparison with the conventional filtering algorithm basing on using the classical Kalman filter with the measurement noise matrix whose elements are fixed.
Metal bioaccumulation potential of the seaweed Kappaphycus alvarezii
Authors: Tresnati J , Yasir I , Zainuddin  , Syafiuddin  , Aprianto R , Tuwo A
Published: July 2021

Kappaphycus alvareziiis one of the two main species of seaweed commodities cultivated in Indonesia.K. alvareziimore popularly known asEucheuma cottonii, is belongs to the red algae. This seaweed is one of the most important commercial sources of carrageenans, a family of gel-forming, viscosifying polysaccharides. Carrageenans are used as gelling, thickening, and stabilizing agents in a variety of commercial applications, especially in food products such as frozen desserts, chocolate milk, cottage cheese, whipped cream, instant products, yoghurt, jellies, pet foods, and sauces. Aside from these functions, carrageenans are used in pharmaceutical formulations, cosmetics, and industrial applications such as mining. This study aimed to analyse the metal bioaccumulation potential of the seaweedK. alvarezii. This study was conducted in three sea areas around South Sulawesi, namely the Gulf of Bone, Flores Sea and the Makassar Strait. Seaweed samples were collected from seaweed cultivation locations in four locations (Regency of Jeneponto in two locations, Takalar and Pangkep). The metal concentrations analysed were Copper (Cu), Cadmium (Cd), and Lead (Pb). The concentration in Cu, Cd, and Pb in the seaweedK. alvareziiwas higher than the concentration in ambient sea water. The seaweedK. alvareziihas a potential as a bioaccumulator, but the accumulation were not consistent. The Cu, Cd, and Pb probably can be accumulated or released back. This is good in terms of food safety because heavy metals can be released during post-harvest processing and carrageenan powder processing. The results of this study indicate thatK. alvareziihas the potential for bioaccumulation, but not permanent accumulation, so it is safe for human health.
Effect of dielectric screening function on binding energy and diamagnetic susceptibility of impurity doped in GaAs conical quantum dots
Authors: Iqraoun E , Sali A , El— Bakkari K
Published: July 2021

In this study, we have investigated the effect of the impurity dependent dielectric screening function on the diamagnetic susceptibility and the binding energy of a shallow-donor impurity confined in a GaAs conical quantum dot (CQD). The calculations have been made within the effective mass approximation, variational method and considering an infinite confining potential. Our results suggest that the effects of the variation of geometrical parameters of CQD are playing a pronounce influence on the diamagnetic susceptibility and the binding energy. The results show that the diamagnetic susceptibility depends strongly on the impurity position and it severely affected by the geometrical parameters of CQD.
First principal calculation and Monte Carlo simulations of the Magnetocaloric effect, Electronic and Magnetic properties in perovskite oxide Pr 0.65Sr 0.35MnO 3
Authors: Kadim G , Masrour R , Jabar A , Hlil E K
Published: July 2021

We have used the first principal calculation and Monte Carlo simulations (MCS) to investigate the magnetocaloric effect, electronic and magnetic properties of Pr 0.65Sr 0.35MnO 3 (PSMO) perovskite. The exchange-correlation potential was treated with the generalized gradient approximation (GGA) for the electronic and magnetic properties. The ferromagnetic phase of PSMO is half metallic with 100% spin polarization, which is important in the relation to the colossal magnetoresistance properties of this compound. The magnetic moment is obtained. The thermal variation of magnetization of PSMO has been obtained. The temperature dependence of the magnetic entropy change and the adiabatic temperature are obtained by MCS. The Curie temperature of PSMO has been deduced. The field dependence of relative cooling power PSMO has been obtained.
Reducing the environmental impact of mining production through the use of man-made waste
Authors: Gorbatyuk N , Adigamov A , Kobelev O , Pashkov A
Published: July 2021

The admissibility of replacing traditional cement, used as a binder with magnesium-containing man-made waste in the preparation of a construction and fill mixture is justified. The possibility of replacing the traditional specially mined aggregate in construction and fill mixtures is proved. The results of testing samples after cementing and a construction-fill mixture prepared on the basis of man-made waste are presented. The positive effect of mechanical activation of the backfill mixture components on its rheological properties and strength characteristics of the fill mass is studied. The use of lignosulfonate as an additive was confirmed to improve the binding and rheological properties of the backfill mixture. The involvement of man-made waste in the closed cycle of the main and auxiliary production reduces the volume of man-made massifs, which significantly reduces the impact of mining production on the environment.
Assessment of the impact of modifier and filler on the physical and mechanical and operational properties of plastering mortars
Authors: Savchenko S , Antoniuk N
Published: July 2021

To assessment of the impact of the addition of microsilica on the mechanical properties of the plaster mortar, experimental-statistical modeling was used. A complex of engineering problems based on models describing the change in the technological and physical and mechanical properties of the plaster mortar during the control of the dosages of microsilica and superplasticizing admix was solved. The problem of choosing the optimal dosage of the filler was solved under the condition of the equality of the water-cement ratio and the mobility of the compositions without and with microsilica additive, which was achieved by appropriate adjusting the dosage of the superplasticizing admix on the consumption of microsilica, i.e. the concentration of the superplasticizing admix was dependent on the consumption of microsilica. Analysis of the effectiveness of the addition of microsilica in the entire factor space using the model of relative efficiency was carried out. The areas of optimal compositions of plaster mortars, in which the increased technological and mechanical parameters are performed, have been determined. An assessment of the effect of ultrafine filler on the operating ability of plaster mortars has been carried out. The main indicators were: the value of adhesion of the plaster layer to the concrete base; the strength of the concrete base (“old” concrete); strength of the plaster layer; indicator of water absorption of the plaster layer. The assessment of the frost resistance of the modified plaster mortar was carried out after 20, 40 and 60 cycles of freezing and thawing. It was found that the proposed modification made it possible to increase the adhesion strength of the plaster layer to the base, save the characteristics of the concrete base after exposure to an aggressive environment, increase the strength of the plaster layer and make it less permeable due to the compaction of the structure, and also to reduce the thickness of the plaster layer without losing its protective properties.
Use of the dactyling effect to obtain a compositional structure in white iron during forming
Authors: Myronova T , Ashkelianets A , Chukhlib V , Biba N , Gubskii S , Okun A
Published: July 2021

Cast iron is traditionally used as a casting alloy for the manufacture of products operating in various industries. White cast irons are used for parts with high wear resistance due to the presence in their composite structure a large number of eutectic carbides, which are located around the dendrites of the solid solution and provide a high level of hardness and strength. The location of eutectic colonies in the form of a mesh causes a low level of ability to withstand impact loading, facilitates the chipping of individual “grains” in abrasive wear and limits the use of these alloys. The use of forming process allows us to grind the eutectic mesh in the structure of white cast iron, which significantly improves the complex of mechanical and operational properties. But the low level of plasticity of white cast iron in the cast state does not allow widespread using white cast iron plastic deformation. The possibility of hot deformation of cast iron workpieces with different speeds and schemes was investigated. The deformation rate of alloys was varied due to the use of different equipment for mass and small-series production using different types of metal forming.
Analysis of the reliability of the plates of complex shapes for the cams of automatic half-hose machines by the criterion of fatigue strength
Authors: Berezin L , Rubanka M , Savchenko K , Polishchuk O
Published: July 2021

The purpose of the work is to develop the algorithm for calculation of the probability of failure-free operation of flexible plates of complex shapes for the cams, using the criterion of fatigue strength, to make decisions on minimization of their sizes with the subsequent evaluation of the implemented measures. The studies are performed on the example of a plate for the cam, the configuration of which provides both beam and double console deformations at the same time. The comprehensive approach is presented, which includes dynamic analysis of the needle impact on the cam surface, computer simulation of geometric parameters of the plate by the finite element method (FEM) according to the condition of strength, and classical principles of mathematical statistics and Theory of Probability. The finite-element model with a volumetric 8-node element is used, which allows, with ease of calculations, to obtain the results with a high accuracy when determining the stress-deformed state of the study object. The computer simulation is performed using Code_Aster software with free access. Also, in the calculation of reliability, the random nature of the multifactorial influence on the value of the plate fatigue limit and the loading variations of the cam are considered. When determining the equivalent forces, taking into account the cyclical operation of the machine, the forces that affect the cams during the production of one product are taken as a loading. The numbers of cycles corresponding to these loadings are calculated by the formulas, which are made as a result of the analysis of trajectories of needles motion concerning the cams when knitting different sections of the product. When calculating equivalent stresses, only stresses that influence the accumulation of fatigue failures are used, that is, the values greater than the half of the detail fatigue limit.

The proposed computational approach can be used to generate the cams with flexible work plates of different configurations, including under the equal stress condition.
The influence of time on the bearing capacity of piles in water-saturated clay soils
Authors: Novskiy A , Bichev I , Novskiy V , Yeresko E
Published: July 2021

The change in the bearing capacity of piles over time is an established fact that is carefully studied by many researchers. Depending on the type of soils and their condition, there is both a decrease (in sandy) and an increase (in clay) in the bearing capacity of piles over time. The most effective increase in bearing capacity occurs in water-saturated, clayey soils with the property of thixotropy. The results of experimental studies of soils with piles in natural conditions, carried out with different periods of their rest, are of considerable value in the study of this phenomenon. During the construction of a multi-storey residential complex in Odessa, which began in 2019, it became necessary to increase the load on the pile foundation made of prismatic piles with a length of 16 m and a cross-section of 350×350 mm. According to research in 2019, the bearing capacity of the piles was 1500 kN. In February 2021, static soil tests were carried out with the existing piles from under the grillage of the building, which was installed by 90%, while the bearing capacity of the piles was 1800 kN. Thus, for the period from July 2019 to February 2021, the bearing capacity of C160.35-11 piles at the construction site in water-saturated soils in Odessa increased from 1500 kN to 1800 kN, which is 20%.
Reliability assessment of cylindrical joints with tensioned roll band of the rolling mill
Authors: Checheneva O N , Pashkov A N , Balakhnina E E , Sizova E I , Devyatiarova V V
Published: July 2021

The work addresses to the problem of ensuring the operability of a composite roll made in the form of a cylindrical joint with the tension of a carbide band and a steel axis. When considering the wear processes, all the characteristics related to the surface microgeometry are combined by a dimensionless complex roughness parameter, which, along with the roughness class, includes the features of the surface treatment technology. To determine the contact pressure associated with the tension, the Lame formula for calculating thick-walled cylinders is used. When a hard-alloy bandage is placed on a steel roll with the tension between the contacting surfaces, a plastic unsaturated or saturated contact is performed, for which a method for calculating the tension values shall be proposed. Formulas are given for determining the maximum permissible torque that does not cause a change in the strength of the joint with tension under conditions of plastic saturated and unsaturated contact. In order to test the strength of the connection elements with tension, the theory of the greatest tangential stresses is applied for two dangerous points located on the inner surfaces of the covered and the covering parts: a formula is obtained for determining the maximum permissible calculated value of tension from the strength condition of the covered part. An example of fitting with the tension of a band made of hard alloy VK8 on a working roll made of improved steel 45 with a diameter of d = 100 mm is considered. The band is installed using a press with an H7/p6 fit to transmit a torque of M = 5 kNm. The minimum tension value is obtained from the condition of fixing the contact surfaces without their relative slippage, and the maximum tension value is obtained from the condition of the strength of the steel axis. As a result of the calculations, it was found that the minimum tolerance for this attachment does not provide the transmission of the specified torque since its value is less than the minimum allowable tension. Therefore, to ensure reliable operation of the connection with tension, it is recommended to use the H7/s6 fit, which provides the transmission of the specified torque without the strength of the connection elements.
Study of metal changes in form during forging of on-off valves
Authors: Chukhlib V , Duvanskii O , Biba N , Ashkelianets A , Gubskii S , Okun A
Published: July 2021

An overview of the existing technological scheme for the production of on-off valves is given. The analysis of the existing shape of the on-off valves was carried out with its classification by the output hole. Depending on the shape of the on-off valve output hole, a new technological process is proposed for obtaining on-off valve with a tapered part of the output hole using free forging. To develop the main forging technological scheme, an analysis of the part of the workpiece that is directly exposed to the technological tool was performed by determining the displaced bulks. For this, the entire bulk of the metal under the influence of the deforming tool was divided into characteristic zones, both before deformation and after its implementation. The analysis of the shape change showed the dependence of the metal flow parameters relates to the main geometric and technological parameters, and for this, the main graphic changes were built. On the basis of these studies, a new technological forging process of on-off valve forged pieces with the maximum approximate shape to the finished product can be developed.
Investigation of the surface properties of quartz-based dispersed materials
Authors: Danchenko Yu , Andronov V , Vazhynskyi S , Khmyrov I , Khmyrova A
Published: July 2021

Researched quartz disperses materials (Ukraine): mineral - quartzite of the Ovruch deposit and quartz sand of the Novovodolazsky deposit and products of processing of quartz minerals - dinas and marshalite. The mineral composition, surface morphology, dispersion and specific surface area were experimentally studied. The structure of the hydroxyl-hydrate surface layer was studied by thermogravimetric (TG) analysis and differential thermal analysis (DTA). The number and acid-base characteristics of surfaces active centers were investigated by the methods of pK-metric and pH-metric. It is established that the mechanisms of physical and chemical adsorption of water molecules on the surface of all quartz dispersed materials are identical and do not depend on the mineral nature of impurities. It is shown that the thickness of the surface hydroxyl-hydrate layer of quartz dispersed materials is determined by the amount of chemically adsorbed water, i.e. the thickness of the hydroxyl layer and depends on the nature of the associated minerals. It is established that the acid-base surface characteristic of quartz materials significantly depends on the chemical nature of the accompanying minerals and does not depend on the thickness of the surface hydroxyl-hydrate layer.
Efficient technologies for making gypsum binders
Authors: Gabitov A I , Salov A S , Ryazanova V A , Timofeev A A , Timofeev V A
Published: July 2021

A number of various proposed options and flow charts applied for the production of gypsum binders are considered herein. Large volumes of inorganic waste amount to millions of tons therefore the phosphogypsum utilization to get effective gypsum binders is an urgent issue. The production of phosphogypsum binders both in our country and abroad is indicated to go in three main directions - burnt, autoclaved and anhydrite (hard-burnt) binders.
Influence of technological factors on the properties of building materials on the basis of expanded alunitized high-silica mountain rocks
Authors: Gots V I , Palchik P P , Palchik S P , Berdnik O Y
Published: July 2021

The influence of technological factors in the production of building materials on the basis of expanded alunitized high-silica rocks on their physical-mechanical and thermal-technical characteristics is determined. It is determined that the production of wall materials with high physical and mechanical and thermophysical characteristics, as well as the ability to obtain products with certain predetermined geometric dimensions, are determined by a set of initial indicators, both properties of raw materials and processes, as well as a certain sequence of individual elemental operations. It is shown that the production of wall materials with high physical and mechanical and thermal characteristics can be achieved by reproducing in the volume of the material of a porous system of closed type with homogeneous, evenly distributed throughout the material pores. The influence of the nature of pores and their textural characteristics of alunitized highly siliceous rocks on the performance properties of building materials has been studied. It is shown that the extension of the service life of these materials without reducing their basic physical and mechanical, thermal and thermal-technical indicators directly depends on the porosity coefficient, the values of their textural values and the nature of the pores. The influence of technological factors on the process of pore formation of alunitized highly siliceous rocks, their textural characteristics and stability of parameters during operation under the influence of aggressive environmental factors are considered. It is determined that the increase in the operating temperature of materials created in compliance with these principles is determined by the morphology and structural characteristics of the source materials by their chemical and mineralogical composition, as well as the influence of process parameters.
Calculation of coast-protecting structure from wave influence
Authors: Grishin A
Published: July 2021

A coupled system consisting of a shore protection structure, a soil base and an aquatic environment is considered. The influence of the aquatic environment on the oscillations of the structure was taken into account. The wave processes arising in the system from the action of surfing and breaking waves were investigated. The developed methodology and software package allow the calculation of various structures interacting with a deformable soil environment from the action of static and dynamic loads, taking into account the real properties of their materials, such as elasticity, viscosity and plasticity. The theory of plastic flow was used. Discretization of the computational area was performed by the finite element method. Studies were carried out on the basis of the obtained schemes of plastic zones, diagrams of stresses and oscillations at various points of the structure.
Research of the process of water absorption by thermally modified wood
Authors: Tsapko Y , Bondarenko O , Horbachova O , Mazurchuk S
Published: July 2021

The analysis of the process of thermal modification of wood, which was obtained by a controlled process of pyrolysis of wood heating (> 180 °C), which causes some chemical changes in the structures of cell wall components (lignin, cellulose and hemicellulose), to increase its durability. It is proved that in the process of thermal modification there is a decomposition of hemicelluloses and amorphous part of cellulose, reduction of water absorption, and also the quantity of substances which are the environment for development of fungi decreases. In addition lignin and psevdolihnin formed by the process of polymerization and redistribution in cell volume and cell walls provide higher density, hardness, increase the hydrophobicity (water repelling), thereby reducing their ability to absorb moisture and swell. Polymerised lignin fills the inside of the cell – formed closed porous structure with low ability to bind water. It was established that the most effective option to reduce such substances are temperature and exposure time. The results of water absorption, dependence on which the calculated diffusion coefficient in the water absorption. Thermal modification of wood reduces water absorption by more than 10 times within 6 hours, which allows it to be used on objects with high humidity.
Some features of oscillations and stability of reinforced cylindrical shells under action of movable inertial loading
Authors: Klyushnyk D , Demianenko A , Zelensky A
Published: July 2021

This paper describes some features of the mathematical models for the elastic shell with movable load and for the elastic elements of changeable length. In these systems two forms of eigenoscillations - the eigen component and the accompanying one, displaced in phase to the right angle correspond to every frequency of the system. The accompanying component is caused by the mobile inertia load or by the changeable length and they are non-trivial when those factors are present. As well as for objects with time-varying length, these problems lie in outside of the scope of the classical problems of mathematical physics due to that the eigenfrequencies and eigenforms will be presented as time-nondependent functions. This non-classical section of the mathematical physics is waiting for its development, new researches and generalizations. The main attention of this work is paid to the elastic systems with the mobile inertia load. The problem of oscillations and stability of thin cylindrical envelope with regular stringer set is being considered under assumption that they are regularly placed with a small step from one to another. Also, we assume that there is unsymmetrical stream of mobile inertia load. There is a wide variety of problems in area of jet engine, cooling systems, flying, and floating vehicle framework’s design, which boil down to such computational schemes. The linear theory of structural-orthotropical envelopes with equilibrium equations and geometrical Donnel-Mushtary relations are being used to obtain of the discussed problem formulation. We assume that ribs of the shell are considered as Kirchhoff-Klebsh bars. The accurate solution of the problem is obtained by using of two-waves representation for motion and it has been applied for research on influence of geometry, elastic and structural parameters on the oscillation and stability properties of the shell.
Laboratory tests of the steel fiber concrete road slab model
Authors: Surianinov M , Neutov S , Korneieva I , Kirichenko D
Published: July 2021

The results of experimental studies of bearing capacity and cracking resistance of road slab models made of steel-fiber concrete according to the span loading scheme are presented. The bearing capacity of the models has been fixed at 27.96 kN, which is 2 times higher than the load corresponding to the beginning of cracking (14.8 kN). At the moment of bearing capacity loss, the height of compressed zone was 1 cm, which is one third of its original size. The relative strains before the first crack appeared were 0.1175×10-4 and 0.235×10-4 in the compressed and stretched zones, respectively, and similar limiting relative strains reached values of 3.715×10-4 and 9.235×10-4. The maximum crack opening width was substantially less than in the same tests of the slabs without dispersion reinforcement and was 0.3 mm, which is explained by the more ductile properties of steel fiber concrete, which prevent crack opening. The final deflection in the middle of the plate model span was 10.4 mm, which is 5.5 times greater than the deflection before cracking began (1.9 mm).
Study of deformation properties of alkali activated concretes using active aggregates
Authors: Kovalchuk O , Zozulynets V
Published: July 2021

Results of study of deformation properties of fine-grain concrete are shown using slag alkali activated cement and active aggregate. It had been shown that expansion deformations of specimens, supplying process of alkaline corrosion of aggregate in concrete, directly combined with component composition and conditions of hardening of material. It was shown that using alkaline component in the state of dry salt shrinkage deformations are varying in the shorter ranges comparing to concrete with the soluble glass. Introduction of active mineral admixture leads to the decreasing of deformations comparing to the compositions without admixture. Different conditions of hardening of the specimens are also influence well on the development of shrinkage deformations. It is shown that drying of specimens with active process of alkaline corrosion of concrete makes it possible to stop development of expansion deformations in concrete. Hydrophobization of the dried specimens make it possible to store linear characteristics of specimens. Hydrophobization of without drying leads to the intensification of structure formation processes and higher rates of development of deformations. Traditional method of protection of concrete constructions (covering by painting materials) is not able to prevent, but also possible to activate development of destructive processes of alkaline corrosion of concrete.
Basics of automation in the formation of matrices of the numerical-analytical method of the boundary elements in calculation of spatial frame structures
Authors: Kushnir A M , Kuchmenko I M , Chub O A
Published: July 2021

The basic principles of the methodology for automating the formation of matrices of the numerical-analytical method of boundary elements (BEM) for the calculation of spatial frame structures are presented.
Influence of boundary forces on the strength of a thin-walled cylindrical tank
Authors: Dziuba L , Lishchynska K , Chmyr O , Tomenko V
Published: July 2021

The strength of a thin-walled cylindrical large-capacity tank was evaluated. The walls of the tank and the bottom are simultaneously exposed to hydrostatic pressure of the liquid and additionally gas pressure-loaded. The stress at the bottom of the tank was determined taking into account the boundary forces under the combined action of hydraulic and gas pressures. The dependences for determining the boundary forces were obtained by solving the equation of deformations compatibility of a thin-walled cylindrical shell and a round plate resting on a solid surface. The influence of gas pressure increase on the magnitude of stresses was investigated.
Investigation of the Stability Conditions of an Automated Control System for a Centrifugal CVT of Automotive Special Equipment
Authors: Lytovchenko V. , Pidhornyy M. , Bondarenko M. , Fedyuk I. , Shapovalov O.
Published: July 2021

Modern continuously variable mechanical transmissions (CVT) with V-belt variators change the gear ratio due to tangential forces. In most cases, both the input and the initial links are geometrically similar wedge disks that move in a linear mode along their axis of rotation, while the process of controlling the transformation of the gear ratio is realized individually for each of the proposed solutions. The authors suggest employing direct action forces, the centrifugal force of the CVT working elements and the variator for transformation, instead of the traditionally used tangential forces. The use of the methods specified above allows reducing power loss by means of mechanical self-regulation of the continuously variable transmission.
Scientifically grounded approach to the prescription of additives for obtaining complex-modified concretes
Authors: Adylkhodzhaev A I , Makhamataliev I M , Tsoy V M , Kondrashchenko V I
Published: July 2021

Annotation

The results of theoretical and experimental studies on the development of a scientifically grounded method of prescribing plasticizing chemical additives and mineral fillers in the selection of the compositions of complex-modified concretes (CMB) at the design stage are presented. The classification of plasticizing additives according to the degree of decrease in the surface tension of water upon their introduction and the activity of mineral additives according to the indicator of the reduced hydration activity, allowing to obtain highly economical MPC with the required properties.
Modelling of wind impacts on silos and silo parks
Authors: Makhinko A , Makhinko N
Published: July 2021

This paper devoted computer modelling of wind impacts on the silos for grain storage in order to obtain their aerodynamic characteristics. This modelling was made in the system of computer analysis Ansys Workbench for various wind conditions and different layouts of silos: separately located silo and silo parks by varying their sizes and mutual arrangement at various angles of the wind pressure. Within the numerical experiment it was obtained not only a huge array of data about the aerodynamic resistance of the silos, but also developed a special technique of the mathematical modelling of the wind effects on the selected class of constructions. This technique is a single software module for the platform Ansys Workbench, which automatically forms an optimal calculation area, makes an estimation of the wind loads on the silo and exports obtained loads in the software package SCAD for calculating the strength and deformability. To achieve this goal it was made the calculation of the same tasks on meshes of different dimensions, set the dimensions of the mesh in different places of the calculation area and installed the minimum required time of computer simulations.
Justification of conditions of application of thermo modified veneer for protection of wooden products from moisture
Authors: Tsapko Y , Horbachova O , Bondarenko O , Mazurchuk S
Published: July 2021

The analysis of the process of thermal modification of wood was carried out and it was found that the treatment causes chemical changes in the structures of wood components (lignin, cellulose and hemicellulose). It is proved that in the process of thermal modification there is a decomposition of hemicelluloses and amorphous part of cellulose, reduced water absorption, and also reduces the amount of substances that are the environment for the development of fungi, which leads to increased durability. In addition lignin and psevdolihnin formed by the process of polymerization and pererozpodilynyu in cell volume and cell walls provide higher density, hardness, increase the hydrophobicity (water repelling), thereby reducing their ability to absorb moisture and swell. It has been experimentally established that in comparison with unmodified veneer, which gained 22.41 % of moisture in two weeks, veneer modified at 250 and 280 °C gained 2.5 times less moisture - on average 8.6 %. It is established that with the increase of the modification temperature to 280 °C, the water absorption decreases more than twice. The results of the research will also allow to purposefully solve further problems on the creation of new methods of thermal modification of wood and the conditions of its operation at various sites.
Optimization of the calculated scheme
Authors: Medved I , Surianinov M , Otrosh Y , Pirohov O
Published: July 2021

Any calculation is preceded by the stage of creating a design scheme of a real design, which would most accurately respond to real operating conditions. The more optimally drawn up the calculation scheme, the less time consuming there will be stages of calculation and designing the corresponding design. There are practically no results of the use of such an approach in the calculations of building structures. This article an attempt is made to show the possibility and feasibility of using “search for solutions” (add-in for Microsoft Excel) at the stage of selecting the optimal parameters of the design scheme.
Investigation of impulse load attenuation in closed-cell foam in the framework of couple stress elasticity
Authors: Mikulich O , Shvabyuk V
Published: July 2021

The article analyzes the processes of attenuation of impulse loads in foam materials with closed-cell. In the framework of the couple stress elasticity, the analysis of the distribution of dynamic radial stresses in foam media with tunnel cavities of constant cross-section under the action of an impulse load of different duration applied to the cavity boundary in the radial direction is performed. An analytical-numerical approach is used for calculating of the dynamic stresses, which is based on the application of the Fourier transform over time and the modified boundary integral equation method. Numerical calculations of the dynamic stresses were performed using the method of mechanical quadrature and collocation method. The modified algorithm for discrete inverse Fourier transform was used for the calculation of the originals of the dynamic radial stresses. Based on the analysis of numerical calculations, the influence of the impulse duration on the attenuation rate of the pulse load in foam media is established.
Nonbearing Wall infill Under Seismic Impacts In Terms Of Non-Linear Static Analysis
Authors: Oleksiy Murashko , Mikola Kubiiovich , Denys Bezushko , Andrii Arsiriy
Published: July 2021

The presence of wall infill during seismic impacts is one of the key factors that significantly affect the seismic stability of buildings. Also, irregularity of configuration in plan and height can often lead to more serious damage comparing to regular buildings, due to torsional oscillations and stress concentration on individual elements. The purpose of this article is to study the behavior of various irregularities in the shape of buildings under seismic impacts in terms of non-linear static analysis, taking into account the non-bearing wall infill. For this purpose, five typical geometric shapes of the building plan used in Ukraine and abroad (rectangular, + shape, L-shaped, T-shaped and 4-shaped) were adopted.

The calculations were performed using the Pushover Analysis (nonlinear static analysis) method in CAD Lira-SAPR 2019. The main parameter that forms the basis for seismic stability analysis is the story drift under seismic impacts. Obtained results indicate the need to take into account the effect of wall infill, as this can lead to an increase in the seismic stability of the building and stress concentration on individual elements, which can lead to their collapse.
Portland cement easy treatability as the basis of concrete structure stable quality
Authors: Nikolaev A P , Kondrachenko E V , Kondrachenko V I
Published: July 2021

An opportunity is discussed to improve operational parameter stability of concrete and reinforced concrete articles on Portland cement basis in heavy-duty environment. Demonstration of binding properties of cements with identical normative parameters was shown to be dissimilar under amended operational conditions. Such behavior may be supposedly connected to insufficiently stable relation between alkalinity and dispersity of consumed Portland cement.

It was found feasible to arrange preventive control of incoming Portland cement with due consideration of its application conditions. The results of such control were shown to be efficient at substantiated correction of applied Portland cement activity.

The purpose of this research has been expansion of methodological basis of mineral binder quality control for stabilization of consumer properties of concrete and reinforced concrete structures produced on their basis.
The results of complex tests of piles during the installation of piled-raft foundations of the grain terminal in difficult soil conditions near the sea coast
Authors: Novsky O V , Marchenko M V , Mosicheva I I , Novsky V O
Published: July 2021

The engineering and geological conditions of the construction site for the designed terminal for processing and transshipment of grain products and its brief structural characteristics were presented; during arranging the zero cycle of the structure for the operative assessment of the accepted parameters of piles and confirmation of their calculated load, a series of dynamic and static tests of prismatic piles were carried out; requirements, normative methods, technology and devices for testing piles were given; calculations and analysis of their results and preliminary assessment of the accepted parameters of the piles were performed; the possibility of operational forecasting and adjustment of the calculated load and parameters of the piles accepted in the project in difficult geological conditions near the edge of the sea coast was shown.
Development of analytical calculation method for axisymmetric oscillations of circular and annular plates on variable Winkler elastic foundation
Authors: Krutii Yu , Surianinov M , Osadchiy V , Kolomiichuk V
Published: July 2021

An analytical method for calculating axisymmetric vibrations of circular and annular plates on a variable elastic Winkler base is presented. The proposed calculation method is based on the exact solution of the oscillation equation with the subsequent development of a method for its numerical implementation. To construct an exact solution, the direct integration method is used, which was previously developed by one of the authors for differential equations with continuous variable coefficients. The proposed method does not require the discretization of the considered structure and it is a real alternative to the application of approximate methods during solving this types of problems. Based on the exact solution of the differential equation, this method will allow to obtain better picture of oscillations in comparison with approximate methods. In fact, the exact solution has qualitative information and forms the most complete picture of the physical phenomenon that is researched.
Influence of the processes taking place in the contact zone “masonry - plaster coating” on the destruction of the wall structure
Authors: Paruta V , Grynyova I , Gnyp O , Lavrenyuk L
Published: July 2021

To create the optimal composition of the plaster solution with the preassigned properties, it is necessary to know the processes taking place in the “masonry-coating” system, including in the contact zone between it and the masonry, the mechanism of its destruction. The purpose of the presented work was to describe the processes of occurrence and growth of cracks in the plaster coating and its contact zone with the masonry, in the process of its application, hardening and operation of the wall structure. In recent years, significant progress has been made in analyzing the reliability of plaster coatings, their behavior during operation, however, there are problems in predicting the evolution of damage in terms of initiation and growth of cracks, which ultimately leads to cracking and delamination of the plaster coating from masonry. The behavior of the plaster coating largely depends on its structure and the structure of the contact zone. The state of the “masonry-coating” system was described and this made it possible to obtain data on the process of its destruction, the appearance and spread of cracks. The system was destroyed according to two main schemes: formation and development of cracks in the coating and in the contact zone. Thus, these researches make it possible to reduce the number of defects in the contact zone with the masonry and increase the service life of the wall structure.
Special aspects of exterior design of elements of stationary and mobile observation constructions
Authors: Petrovska Yu
Published: July 2021

The article systematizes scientific, informational, regulatory and reference literature on the research topic. Construction schemes of stationary, mobile and transportable Ferris wheels are considered, and their common and distinctive features and peculiarities are outlined. Designs of the world’s highest Ferris wheels are illustrated, the history of their creation, types, design and functional features are described. Special aspects of construction of amusement towers as objects of the short-term panoramic observation of the area are specified. The functional purpose of metal observation constructions used in the entertainment industry is discussed. The development of the tourist industry of cities with active sightseeing attractions is analyzed. Conclusions of the scientific research are drawn and prospects for the development of observation constructions as amusement facilities and landmarks of the urban environment are described.
Investigation of the Conditions for the Use of Material with the Shape Memory Effect in the Sprinklers
Authors: Petukhova O , Gornostal S , Sherbak S
Published: July 2021

The expediency of using nitinol, which is a material with the shape memory effect (SME), as a sensitive element (SE) of a sprinkler has been substantiated. The influence of various parameters on the SE dimensions is analyzed and it is shown that the response time of an element made of a material with the shape memory effect depends on the dimensions of the fixing device (FD) (the diameter of the glass bulb and its thickness). Calculations have shown that the use of the material minimizes the response time of the sprinkler. It is shown that the response time depends on the voltage (or current) in the electrical network, on the size of the fixing device, the cross-sectional radius of the actuator and the critical temperature at which the actuator is triggered.
Development of tools (laboratory facilities) for researching the effect of physical properties of landfill soils on slope stability
Authors: Rashkevich N , Strelec V , Shcherbak S , Yeremenko S
Published: July 2021

The paper presents a developed laboratory unit and a technique for conducting experimental studies of the effect of physical properties of landfill soils, such as moisture, density, temperature, on slope stability in order to verify the reliability of a mathematical model and a methodology for preventing emergencies associated with displacement developed on its basis. Conducted field studies of humidity, density, temperature of landfill soils of typical solid waste disposal facilities. The analysis of the conditions for obtaining the maximum amount of methane in the composition of biogas has been carried out. The basic requirements for the laboratory unit have been determined and the area of the factor space for conducting experimental laboratory studies has been established.