bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determining the effect of reinforcing a cement-concrete coating of bridges on the stressed-strained state of structures
Authors: Gameliak Igor , Dmytrychenko Andrew , Tsybulskyi Vitalii , Kharchenko Anna 
Published: March 2022

This paper reports a study of the cement-concrete coating on bridges using FRP reinforcement. That has made it possible to design optimal structures by selecting the height for reinforcement arrangement in the layers of a roadbed in order to ensure strength characteristics.
An engineering method for calculating a hard roadbed with composite reinforcement has been devised, which makes it possible to take into consideration its work both in a joint package of the structure with a slab and separately – when it exfoliates from the slab of the bridge's span structure. Underlying this research are effort-determining methods, estimation dependences from the theory of bending layered structures, as well as dependences from elasticity theory to assess the strength of materials for a roadbed. The consideration of shear strains when designing slabs has helped establish that the deflections according to the devises method were 1.4 times larger than those in the classical approach.
The method was tested by a numerical experiment, which confirmed the need to use composite reinforcement in the upper layers of a road surface on bridges, which improves its durability by 1.2 times. The results of the numerical experiment indicate that the equivalent stresses in the lower layers of a free-moving roadbed were 2.91 MPa, and, when operating in a joint assembly with a slab, they took a negative value (–0.2 MPa).
Practical application of the devised calculation method makes it possible to determine the refined normal stresses in the layers of a roadbed, taking into consideration the characteristics of structure operation. Owing to this, additional opportunities open up for calculating the roadbeds of bridges whose design utilizes the most common types of span structures in the bridge industry.
Analyzing the accuracy of detecting steganograms formed by adaptive steganographic methods when using artificial neural networks
Authors: Progonov Dmytro , Yarysh Mariia 
Published: March 2022

This paper reports a comparative analysis of accuracy in the detection of steganograms formed according to adaptive steganographic methods, using steganography detectors based on common and specialized types of artificial neural networks. The results of the review of modern convolutional neural networks applied for the tasks of digital image stegoanalysis have established that the accuracy of operating the steganography detectors based on these networks is significantly compromised when processing image packets characterized by a significant variability of statistical parameters.
The performance accuracy of steganography detectors based on the modern statistical model of container images maxSRMd2 has been investigated, as well as on the latest convolutional and «hybrid» artificial neural networks, in particular, GB-Ras and ASSAF networks, when detecting steganograms formed according to the adaptive steganographic methods HUGO and MiPOD. It was established that the use of the statistical model maxSRMd2 makes it possible to significantly (up to 30 %) improve the accuracy of steganogram detection in the case of analyzing those images that are characterized by a high level of natural noise. It was found that the use of the ASSAF network makes it possible to significantly (up to 35 %) reduce an error of steganogram detection compared to current steganography detectors based on the GB-Ras network and the maxSRMd2 statistical model. It was determined that the high accuracy of the ASSAF network-based steganography detector is maintained even in the most difficult case of image processing with high noise and poor filling of the container image with stegodata (less than 10 %).
The results reported here are of theoretical interest for designing high-precision steganography detectors capable of working under conditions of high variability in image parameters.
Development of compression algorithms for hyperspectral aerospace images based on discrete orthogonal transformations
Authors: Sarinova Assiya , Dunayev Pavel , Bekbayeva Aigul , Mekhtiyev Ali , Sarsikeyev Yermek 
Published: March 2022

The work is devoted to the description of the development of compression algorithms for hyperspectral aerospace images based on discrete orthogonal transformations for the purpose of subsequent compression in Earth remote sensing systems. As compression algorithms necessary to reduce the amount of transmitted information, it is proposed to use the developed compression methods based on Walsh-Hadamard transformations and discrete-cosine transformation. The paper considers a methodology for developing lossy and high-quality compression algorithms during recovery of 85 % or more, taking into account which an adaptive algorithm for compressing hyperspectral AI and the generated quantization table have been developed. The existing solutions to the lossless compression problem for hyperspectral aerospace images are analyzed. Based on them, a compression algorithm is proposed taking into account inter-channel correlation and the Walsh-Hadamard transformation, characterized by data transformation with a decrease in the range of the initial values by forming a set of channel groups [10–15] with high intra-group correlation [0.9–1] of the corresponding pairs with the selection of optimal parameters. The results obtained in the course of the research allow us to determine the optimal parameters for compression: the results of the compression ratio indicators were improved by more than 30 % with an increase in the size of the parameter channels. This is due to the fact that the more values to be converted, the fewer bits are required to store them. The best values of the compression ratio [8–12] are achieved by choosing the number of channels in an ordered group with high correlation.
Improvement of refrigerating machine energy efficiency through radiative removal of condensation heat
Authors: Tsoy Alexandr , Titlov Oleksandr , Granovskiy Alexandr , Koretskiy Dmitriy , Vorobyova Olga , Tsoy Diana , Jamasheva Rita 
Published: March 2022

In regions with a continental climate, refrigerators with air-cooled condensers operate at high condensation pressures during the summer season which reduces their efficiency and accelerates the wear of compressors. To reduce condensation pressure, it was proposed to use radiative cooling which is a way of heat removal through the planet's atmosphere to outer space in a form of infrared radiation. A refrigerating machine with an assembly of condensation heat removal including air and liquid cooling condensers connected in series has been developed. To reduce the condensation temperature, a pre-cooled heat-transfer agent is fed to the liquid cooling condenser during the day hours at high atmospheric temperatures. At night, the heat-transfer agent is cooled by radiative cooling.
An experimental study of the operation of a 600 W refrigerating machine including a sealed piston compressor was conducted. R134a refrigerant was used. Supply of pre-cooled heat-transfer agent at +33.1 °С has provided a reduction of condensation temperature from +47.0 to +39.1 °С. The study was conducted at an atmospheric air temperature of +38.0 °С. The degree of pressure growth was decreased by 30 %. The refrigeration coefficient was increased by 11 %. In comparison with the conventional scheme with an air-cooled condenser, energy consumption by the system did not change in the daytime.
The offered scheme of condensation heat removal reduces the pressure of condensation and provides stability for refrigerating machine operation. It can be used in stationary refrigerating machines at high daytime temperatures.
Improving the efficiency of finishing-hardening treatment of gas turbine engine blades
Authors: Pavlenko Dmytro , Kondratiuk Eduard , Torba Yuriy , Vyshnepolskyi Yevhen , Stepanov Dmytro 
Published: March 2022

This paper considers the influence of the technology to finish and strengthen compressor blade tips made of EP718-ID alloy on the characteristics of the surface quality, surface layer, and bearing capacity. Taking into consideration the special role of the finishing-strengthening treatment in the formation of the quality of the surface layer, various options for blade tip processing were investigated. The blade tips were shaped by high-speed line milling. The finishing-strengthening stage of tip machining included manual polishing and ultrasonic hardening operations with steel balls in various combinations.
The basic regularities have been established in the formation of the roughness of tip surfaces, the maximum height of micro-irregularities, the surface microhardness, and the propagation depth of the hardened layer, depending on the combination of finishing-strengthening machining techniques. The results of tests are given for multi-cycle fatigue of blade batches treated according to various variants of the technological process. The efficiency of polishing the surface of the tip after strengthening treatment has been established. To restore the quality characteristics of the surface layer after polishing, it is proposed to perform repeated strengthening treatment. It is shown that the use of double deformation hardening technology with intermediate polishing at the finishing-strengthening stage of blade manufacturing makes it possible to increase the endurance limit from 320 MPa to 400 MPa while increasing durability. Technology for the finishing-strengthening stage of machining blades made from nickel alloys, characterized by significant viscosity, has been devised. It is shown that based on the criteria of minimum labor intensity of machining and maximum endurance of blades, it is effective to use double deformation hardening with steel balls in an ultrasonic field with intermediate polishing.
Coagulation treatment of effluent from milk-processing enterprises with waste FeSO4
Authors: Kurylets Oksana , Helesh Andriy , Vasiichuk Viktor , Znak Zenoviy , Romaniv Anna 
Published: March 2022

As the world's population grows, the problem of food shortages becomes global, and, for human survival, it is necessary to significantly increase food production, which may increase environmental pollution.
This paper has theoretically and practically substantiated the expediency of coagulation treatment of wastewater from milk-processing enterprises. The coagulant proposed to use is a multi-tonnage waste from industrial enterprises, specifically technical ferrous sulfate.
It is shown that it is advisable to use the dairy effluent imitations based on milk powder for experimental studies.
The potentiometric titration of dairy effluent imitations has established the presence of two points (pH=4.2 and 8.3), which characterize the boundaries of the buffering capacity of solutions. The expediency of carrying out the process of coagulation of dairy effluents in a weakly alkaline environment at pH≥8.3 has been substantiated, and, for the starting effluent to reach such a pH value, a 10-% suspension of Са(ОН)2 should be used. The effectiveness of reagent treatment of dairy effluents has been experimentally confirmed, subject to the alternate introduction of a coagulant (technical FeSO4) and flocculant (polyacrylamide) in the quantities of 120 and 40 mg/dm3, respectively; the degree of clarification of dairy effluents is 90 % while the residual COC value is 76 mgO2/dm3.
It has been shown that when ultrasound was applied, it was possible to significantly reduce the interaction time and the amount of Са(ОН)2 suspension necessary to achieve pH≥8.3.
Thus, there are grounds to assert the prospects for devising highly effective technology for the coagulation treatment of wastewater from milk-processing enterprises; the results and conclusions reported here about the technological feasibility of using technical FeSO4 as a coagulant could be practically applied for other technologies of coagulation wastewater treatment, provided that its pH value is brought to 8.3.
Investigation of the appearance and elimination of pinking coloration in white wines
Authors: Bilko Marina , Gunko Sergiy , Babych Iryna , Naumenko Oksana , Mukoid Roman , Ischenko Mykola , Doboniy Inna , Danylenko Svetlana , Bovkun Alla , Stotska Olena 
Published: March 2022

Investigation of the appearance and elimination of “pinking” phenomenon in white wines is presented in the paper. Several factors that can cause pinking were analyzed: the degree of grapes ripeness and enzymatic treatment. The effect of fining agents based on polyvinylpolypyrrolidone (PVPP) on the elimination of “pinking” was determined. It was proved that pinking in wines decreases with an increase in the sugar content in grape. This is explained by a decrease in the content of anthocyanins at the end of technical ripeness of grape. Experimental studies confirmed that the use of pectolytic enzymes with cellulase, hemicellulase, β-glucanase activities increases the intensity of straw color and the appearance of body tones, but does not affect pinking. Such treatment contributed to a slight increase in the content of phenolic compounds in wine materials, but did not affect the content of anthocyanins and “pinking” susceptibility. Treatment of wine materials with complex PVPP-based agents including sorbents and flocculants, is an effective way to eliminate the “pinking” phenomenon. This reduces “pinking” in wine materials from 70…90 % to 1…2 %. This is due to the presence of sorbents and flocculants in the fining agents, which react with phenolic substances that cause “pinking” in white wines, and remove them from the system. So, there are reasons to argue that processing grape at the end of technical ripeness will contribute to a lower “pinking” susceptibility of wine materials; pectolytic enzymes did not affect the appearance of this phenomenon in white wines, and PVPP-based fining agents together with bentonite, activated carbon, gelatin or casein, are an effective way to reduce the “pinking” susceptibility of wine.
Improving the accuracy and performance speed of the digital spectral-correlation method for measuring delay in radio signals and direction finding
Authors: Sabibolda Akezhan , Tsyporenko Vitaliy , Tsyporenko Valentyn , Smailov Nurzhigit , Zhunussov Kanat , Abdykadyrov Askar , Baigulbayeva Moldir , Duisenov Nurzak 
Published: March 2022

A promising direction for the development of passive radar monitoring stations is to improve their efficiency by increasing their speed of performance. For the digital spectral-correlation method for determining the delay of radio signals and direction finding, analytical expressions have been derived for a variance of the estimation of the delay in receiving a signal by radio channels and directions to the source of radio emission. A feature of the method reported in this study is the use of two-stage temporal and spatial spectral analysis of the mutual spectrum, a single-iteration correlation analysis.
The duration of estimating the direction finding has been evaluated through the total number of multiplication operations with accumulation. The proposed method, while providing for a gain of 27 times in terms of performance speed, demonstrated a slight decrease in accuracy compared to the optimal one due to energy signal loss.
The result of the simulation has established the dependences of the standard deviation in the direction finding and delay estimates on the signal-to-noise ratio, the type of spectral analysis window, and the size of the antenna base.
The standard deviation of the direction-finding estimate depends on the signal-to-noise ratio and varies over the range of values [0.08; 0.034]° with a change in the signal/noise ratio [−10; 40] dB. As the signal/noise ratio increases, the error decreases in line with a hyperbolic dependence. The standard deviation of the delay estimate depends on the signal-to-noise ratio and varies similarly to the error of the directional estimate, and is in the range of values [18.176; 1.56] ns, which corresponds to an error of [0.637; 0.055] %. The error of direction-finding estimation, depending on the size of the antenna base, decreases in the exponent within [1.6; 0.03]° with an increase in the antenna base in the range from 200 to 7,500 m.
The results reported here could be used for the parametric optimization of spectral-correlation radio direction finders at passive radar monitoring stations.
Optimization of mechanical properties of recycled polyurethane waste microfiller epoxy composites using grey relational analysis and taguchi method
Authors: Abed Salwa A. , Khalaf Ahmad A. , Mnati Hayder Mohammed , Hanon Muammel M. 
Published: March 2022

Mechanical properties and thermal conductivity of epoxy composites reinforced with recycled clamshell container waste as a micro filler (RCCF) were studied. The studies have been carried out to identify the influence of the two variables, the heating time periods (HT) within the range of 2, 4, 6 min., and wt % within the range of 1 %, 2 %, 4 % of recycled clamshell container waste that has been used as a reinforcing filler of epoxy composites. Recycling polyurethane waste aims to control and maintain a pollution-free environment, which is currently considered a difficult issue in addition to achieving low-cost aspects in preparing the composites. According to the method of no-combustion heating, the clamshell waste was converted from the natural plastic state into solids that were later made into 75 μm micro filler by grinding. Composites were ranked using grey relational analysis (GRA). The effect of each control parameter on response variables was analyzed by the Taguchi method. Using MINITAB 19 software, regression equations were obtained for each variable of mechanical properties and thermal conductivity to predict the properties of epoxy composites. The results of the addition of recycled clamshell container waste to epoxy resin show an improvement in the mechanical properties and thermal conductivity of the composites. The optimal value of the two factors was at HT2wt2, i.e. HT and wt % of 4 min and 2 %, respectively. The optimization values for the bending strength, impact strength, tensile strength, stiffness and thermal conductivity are 68.2 MPa, 10.348 kJ/m2, 21.08 MPa, 80 Shore D and 0.504 W/m·C°, respectively. The proposed Taguchi methodology based on grey relational analysis has been shown to be effective in solving multi-feature decision-making problems.
Development of a modification of the method for constructing energy-efficient sensor networks using static and dynamic sensors
Authors: Petrivskyi Volodymyr , Shevchenko Viktor , Yevseiev Serhii , Milov Oleksandr , Laptiev Oleksandr , Bychkov Oleksii , Fedoriienko Vitalii , Tkachenko Maksim , Kurchenko Oleg , Opirskyy Ivan 
Published: March 2022

Due to the widespread use of sensors and sensor networks in the tasks of territory coverage, the relevant criteria are maximizing coverage and minimizing energy consumption. At the same time, the compliance of the network with these criteria is an urgent problem in the modern technological world. A modification of the method for constructing energy-efficient sensor networks is proposed by introducing an additional criterion for minimizing the number of sensors and limiting the number of sensors used, which allows reducing the energy consumption of sensor networks by 19 %. In the resulting optimization problem, the optimality criteria are the functions of minimizing the area of uncovered territory, the value of energy consumption, and the number of sensors. The optimum solution is formed by pairs of values of the coverage radius and the level of intersection of the coverage areas, which provide maximum coverage while minimizing energy consumption and the number of sensors used. To solve the problem, the parameter convolution method and the genetic algorithm were used. In the case of dynamic sensors, the problem is to find such a trajectory of the sensor that provides the maximum flyby of the territory with a minimum length. A grid algorithm is proposed to find the necessary trajectory. The presented algorithm consists in dividing the territory into nodes and estimating the value of the covered territory by the sensor in this node. After the formation of estimates, the search for a Hamiltonian path was used. The case of a multiply connected territory with the possibility of turning it into a simply connected one is considered. A scheme for finding the parameters of energy-efficient coverage of the territory using static and dynamic sensors is proposed.
Improving the efficiency of the coal grinding process in ball drum mills at thermal power plants
Authors: Kamarova Saule , Abildinova Saule , Terziev Angel , Baydusenov Galym 
Published: March 2022

Ensuring the reliable operation of the dust fuel preparation system at thermal power plants (TPP) is a topical issue since it determines the energy strategy of any country that fires coals for thermal energy production. This unit is one of the most energy-intensive units in TPP. Those systems are outdated, poorly automated and high energy-intensive. Furthermore, they must ensure efficient and safe operation of the facility while being environmentally friendly. The current work focuses on the process of grinding coals in ball drum mills for further pulverized combustion. An experimental study was performed in order to determine the main factors (rotational speed of the drum mill, the degree of loading with the grinding balls, and the velocity of the supplied air) that affect the efficiency of the fuel preparation system. The obtained experimental data and performed mathematical modeling resulted in regression equations describing the energy performance of the mill. Three regression equations for mill productivity, power consumed, and specific surface area of the final product were obtained and validated. The study reveals that the lowest specific energy consumption is achieved when the relative rotational speed of the mill is between 0.81 and 0.87; the weighted average diameter of the balls ranges from 33.5 up to 34.5 mm; the load factor of the grinding media ranges from 0.325 up to 0.335, the supplied air velocity is between 0.2 and 0.3 m/s. The proposed methodology allows adjustment of the operating parameters of the grinding process to achieve the lowest energy consumption. The power consumption for the preparation can be reduced up to 5 % for the selected operation mode of the grinding facility.