bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a method for estimating the effect of transformation of the normalized frequency mismatch function of a coherent bundle of radio pulses on the quality of radar frequency resolution
Authors: Yevseiev Serhii , Biesova Oksana , Kyrychenko Dmytro , Lukashuk Olena , Milevskyi Stanislav , Pohasii Serhii , Husarova Iryna , Goloskokova Anna , Sobchenko Volodymyr
Published: September 2021

The necessity of studying the influence of the transformation of the frequency mismatch function of a coherent bundle of radio pulses on the quality of solving the radar frequency resolution problem is substantiated. This solution determines the effectiveness of radar observation of high-speed and maneuvering individual and group aerodynamic objects. The method is based on explicit expressions for calculating the normalized frequency mismatch function of a coherent bundle of radio pulses, taking into account its transformation due to the radial motion of high-speed and maneuvering individual and group aerodynamic objects. The estimation of the potential frequency resolution of bundles with different numbers of radio pulses with typical parameters for a coherent pulse radar is carried out. Possible values of frequency resolution under the additive effect of uncorrelated internal noise of the radar receiver and the multiplicative effect of correlated phase fluctuations of the radar signal are estimated. With an insignificant multiplicative effect of correlated phase fluctuations, a twofold increase in the number of radio pulses in a bundle provides an improvement in the frequency resolution (reduction of the width of the normalized frequency mismatch function) by 100 %. With the predominant multiplicative effect of these fluctuations, a twofold increase in the number of radio pulses results in an improvement in the frequency resolution by about 40 %. The developed method is of great theoretical and practical importance for the further development of the radar theory of high-speed and maneuvering individual and group aerodynamic objects.
Establishing conditions for the existence of bounded solutions to the weakly nonlinear pulse systems
Authors: Asrorov Farhod , Perehuda Oleh , Sobchuk Valentyn , Sukretna Anna
Published: September 2021

Processes that involve jump-like changes are observed in mechanics (the movement of a spring under an impact; clockwork), in radio engineering (pulse generation), in biology (heart function, cell division). Therefore, high-quality research of pulse systems is a relevant task in the modern theory of mathematical modeling.
This paper considers the issue related to the existence of bounded solutions along the entire real axis (semi-axis) of the weakly nonlinear systems of differential equations with pulse perturbation at fixed time moments.
A concept of the regular and weakly regular system of equations for the class of the weakly nonlinear pulse systems of differential equations has been introduced.
Sufficient conditions for the existence of a bounded solution to the heterogeneous system of differential equations have been established for the case of poorly regularity of the corresponding homogeneous system of equations.
The conditions for the existence of singleness of the bounded solution along the entire axis have been defined for the weakly nonlinear pulse systems. The results were applied to study bounded solutions to the systems with pulse action of a more general form.
The established conditions make it possible to use the classical methods of differential equations to obtain statements about solvability and the continuous dependence of solutions on the parameters of a pulse system.
It has been shown that classical qualitative methods for studying differential equations are mainly naturally transferred to dynamic systems with discontinuous trajectories. However, the presence of a pulse action gives rise to a series of new specific problems.
The theory of systems with pulse influence has a wide range of applications. Such systems arise when studying pulsed automatic control systems, in the mathematical modeling of various mechanical, physical, biological, and other processes.
Method for determining coordinates of airborne objects by radars with additional use of ADS-B receivers
Authors: Khudov Hennadii , Diakonov Oleksii , Kuchuk Nina , Maliuha Volodymyr , Furmanov Kostiantyn , Mylashenko Ihor , Olshevskyi Yurii , Stetsiv Stanislav , Solomonenko Yuriy , Yuzova Iryna
Published: September 2021

The method of determining coordinates of an airborne object using ADS-B receivers was improved. The method involves the following sequence of actions: input of initial data, measurement of coordinates of the airborne object by the radar, checking the availability of data about the airborne object obtained from the ADS-B receivers. In the absence of such data, coordinates of the airborne object are determined only from the data of the radar. The airborne object mark was identified according to information from the radar and the ADS-B receivers. Unlike the known methods, the advanced method of determining coordinates of an airborne object by a radar additionally uses information from the ADS-B receivers.
The ADS-B receiver signals were experimentally studied. It was found that the ADS-B receiver has received more than 6,000 messages about airborne objects in a single day. It was established that information about the location of the airborne object contained in ADS-B messages was encoded in CPR format. An algorithm for decrypting the ADS-B messages with a global connection of an airborne object to geographical coordinates was presented. An algorithm for detecting signals of onboard transponders of ADS-B airborne objects was presented. Non-standard ADS-B messages from airborne objects were studied. It was suggested that some short non-standard ADS-B messages were received from small and military airborne objects.
Accuracy of determining coordinates of airborne objects by the radar with additional use of the ADS-B receiver was estimated. Dependence of the root mean square error of determining the airborne object coordinates on a distance to the airborne object was presented for various cases. It was established that the accuracy of determining the airborne object coordinates can be raised from 36 % to 67 % depending on the distance to the airborne object
Determination of the influence of a filler on the properties of composite materials based on polytetrafluorothylene for tribosystems of mechanisms and machines
Authors: Dudin Volodymyr , Makarenko Dmytro , Derkach Oleksii , Muranov Yevhen
Published: September 2021

This paper reports a comprehensive laboratory study into the thermophysical, physical-mechanical characteristics, and tribological properties of the designed composite materials based on polytetrafluoroethylene. In the structures of machines and mechanisms, a significant role belongs to the tribological conjugations made from polymeric and polymer-composite materials. The reliability of machines, in general, depends to a large extent on the reliability of movable connections. Composite materials of nonmetallic origin have a low cost, they are resistant to most aggressive chemicals and are capable of operating under conditions without lubrication. It was established that the characteristics and properties of materials must be adapted to the working conditions of separately considered tribological conjugations.
The mechanisms of thermal destruction have been established, both in the basic material and the carbon fiber based on it. It was found that carbon fiber, regardless of its content (quantity) in the polymer-composite material based on polytetrafluoroethylene, is mainly oriented perpendicular to the force application plane. It was found that with an increase in the carbon fiber content from 10 to 40 % by weight, the heat capacity decreases by 16‒39 % compared to the main material. The optimal operating modes for the designed composite materials have been substantiated on the basis of a pv factor: under a dry friction mode – up to 4 MPa∙m/s; at friction with lubrication – up to 36.4 MPa∙m/s. The dependence has been established of the friction coefficient on the operating modes of a composite material based on polytetrafluoroethylene containing 20 % by weight of carbon fiber when lubricated with oil and water.
The results reported here make it possible to synthesize the physical-mechanical characteristics and tribological properties of composite materials in accordance with the required modes of tribological conjugation.
Development of heart attack prediction model based on ensemble learning
Authors: Hasan Omar Shakir , Saleh Ibrahim Ahmed
Published: September 2021

With the advent of the data age, the continuous improvement and widespread application of medical information systems have led to an exponential growth of biomedical data, such as medical imaging, electronic medical records, biometric tags, and clinical records that have potential and essential research value. However, medical research based on statistical methods is limited by the class and size of the research community, so it cannot effectively perform data mining for large-scale medical information. At the same time, supervised machine learning techniques can effectively solve this problem. Heart attack is one of the most common diseases and one of the leading causes of death, so finding a system that can accurately and reliably predict early diagnosis is an essential and influential step in treating such diseases. Researchers have used various data mining and machine learning techniques to analyze medical data, helping professionals predict heart disease. This paper presents various features related to heart disease, and the model is based on ensemble learning. The proposed system involves preprocessing data, selecting attributes, and then using logistic regression algorithms as meta-classifiers to build the ensemble learning model. Furthermore, using machine learning algorithms (Support Vector Machines, Decision Tree, Random Forest, Extreme Gradient Boosting) for prediction on the Framingham Heart Study dataset and compared with the proposed methodology. The results show that the feasibility and effectiveness of the proposed prediction method based on group learning provide accuracy for medical recommendations and better accuracy than the single traditional machine learning algorithm.
Construction of an advanced method for recognizing monitored objects by a convolutional neural network using a discrete wavelet transform
Authors: Slyusar Vadym , Protsenko Mykhailo , Chernukha Anton , Gornostal Stella , Rudakov Sergey , Shevchenko Serhii , Chernikov Oleksandr , Kolpachenko Nadiia , Timofeyev Volodymyr , Artiukh Roman
Published: September 2021

The tasks that unmanned aircraft systems solve include the detection of objects and determining their state. This paper reports an analysis of image recognition methods in order to automate the specified process. Based on the analysis, an improved method for recognizing images of monitored objects by a convolutional neural network using a discrete wavelet transform has been devised. Underlying the method is the task of automating image processing in unmanned aircraft systems. The operability of the proposed method was tested using an example of processing an image (aircraft, tanks, helicopters) acquired by the optical system of an unmanned aerial vehicle. A discrete wavelet transform has been used to build a database of objects' wavelet images and train a convolutional neural network based on them. That has made it possible to improve the efficiency of recognition of monitored objects and automate a given process. The effectiveness of the improved method is achieved by preliminary decomposition and approximation of the digital image of the monitored object by a discrete wavelet transform. The stages of a given method include the construction of a database of the wavelet images of images and training a convolutional neural network. The effectiveness of recognizing the monitored objects' images by the improved method was tested on a convolutional neural network, which was trained with images of 300 monitored objects. In this case, the time to make a decision, based on the proposed method, decreased on average from 0.7 to 0.84 s compared with the artificial neural networks ResNet and ConvNets.
The method could be used in the information processing systems in unmanned aerial vehicles that monitor objects; in robotic complexes for various purposes; in the video surveillance systems of important objects
Analysis of transient mixed convection in a horizontal channel partially heated from below
Authors: Mashkour Mahmoud A.
Published: September 2021

The heat convection phenomenon has been investigated numerically (mathematically) for a channel located horizontally and partially heated at a uniform heat flux with forced and free heat convection. The investigated horizontal channel with a fluid inlet and the enclosure was exposed to the heat source from the bottom while the channel upper side was kept with a constant temperature equal to fluid outlet temperature. Transient, laminar, incompressible and mixed convective flow is assumed within the channel. Therefore, the flow field is estimated using Navier Stokes equations, which involves the Boussinesq approximation. While the temperature field is calculated using the standard energy model, where, Re, Pr, Ri are Reynolds number, Prandtl number, and Richardson number, respectively. Reynolds number (Re) was changed during the test from 1 to 50 (1, 10, 25, and 50) for each case study, Richardson (Ri) number was changed during the test from 1 to 25 (1, 5, 10, 15, 20, and, 25). The average Nusselt number (Nuav) increases exponentially with the Reynold number for each Richardson number and the local Nusselt number (NuI) rises in the heating point. Then gradually stabilized until reaching the endpoint of the channel while the local Nusselt number increases with a decrease in the Reynolds number over there. In addition, the streamlines and isotherms patterns in case of the very low value of the Reynolds number indicate very low convective heat transfer with all values of Richardson number. Furthermore, near the heat source, the fluid flow rate rise increases the convection heat transfer that clarified the Nusselt number behavior with Reynolds number indicating that maximum Nu No. are 6, 12, 27 and 31 for Re No. 1, 10, 25 and 50, respectively
Devising optimal technological parameters for spray drying to produce whole camel milk powder
Authors: Aralbayev Nurbek , Dikhanbayeva Fatima , Yusof Yus Aniza Binti , Tayeva Aigul , Smailova Zhuldyz
Published: September 2021

Camel milk is a valuable source of protein and nutrients, it has therapeutic and prophylactic properties. The production of dry dairy products based on camel milk implies prolonging its shelf life, a decrease in the cost of its transportation and storage. To manufacture dry camel milk, it is necessary to optimize the technological parameters of drying, which affect its physical-chemical properties.
Whole milk from camels (Camelus dromedarius) was dried on a spray drying plant under the following modes: the inlet temperature from 140 °C to 160 °C; the feed rate from 30 ml/min to 40 ml/min. The dependence of such physical properties of milk powder as the water solubility index, water absorption index, moisture content, hygroscopicity, density, water activity, the stickiness and size of particles on the technological parameters of drying has been established.
The study results show that the highest index of solubility of samples was equal to 81.25±0.11 %, which corresponded to the air temperature at the inlet of 150 °C and the feed rate of 30 ml/min. At the same time, the lowest solubility was 62.89±0.27 % under the modes of 140 and 40 ml/min, respectively. With an increase in the air temperature at the inlet and a decrease in the rate of supply of dairy raw materials, there was a decrease in the moisture content and water activity. However, an increase in the air temperature at the inlet above 150 °C led to a decrease in the solubility index in water. The optimal particle sizes of whole camel milk powder, preceding a relatively high solubility index, were 36.22±0.33 μm, 108.89±0.56 μm, and 229.19±0.74 μm.
The data reported in this paper could be useful in devising the technology for manufacturing a dry milk product from camel milk.
Enhancement of energy transfer efficiency for photovoltaic (PV) systems by cooling the panel surfaces
Authors: Majdi Hasan Shakir , Mashkour Mahmoud A. , Habeeb Laith Jaafer , Sabry Ahmad H.
Published: September 2021

The thermal coefficient of a solar photovoltaic (PV) panel is a value that is provided with its specification sheet and tells us precisely the drop in panel performance with rising temperature. In desert climates, the PV panel temperatures are known to reach above 70 degrees centigrade. Exploring effective methods of increasing energy transfer efficiency is the issue that attracts researchers nowadays, which also contributes to reducing the cost of using solar photovoltaic (PV) systems with storage batteries. Temperature handling of solar PV modules is one of the techniques that improve the performance of such systems by cooling the bottom surface of the PV panels. This study initially reviews the effective methods of cooling the solar modules to select a proper, cost-effective, and easy to implement one. An active fan-based cooling method is considered in this research to make ventilation underneath the solar module. A portion of the output power at a prespecified high level of battery state-of-charge (SOC) is used to feed the fans. The developed comparator circuit is used to control the power ON/OFF of the fans. A Matlab-based simulation is employed to demonstrate the power rate improvements and that consumed by the fans. The results of simulations show that the presented approach can achieve significant improvements in the efficiency of PV systems that have storage batteries. The proposed method is demonstrated and evaluated for a 1.62 kW PV system. It is found from a simultaneous practical experiment on two identical PV panels of 180 W over a full day that the energy with the cooling system was 823.4 Wh, while that without cooling was 676 Wh. The adopted approach can play a role in enhancing energy sustainability.
Thermal destruction of polymers: analysis of the process physicochemical parameters
Authors: Sezonenko Oleksii , Vasechko Oleksii , Aleksyeyenko Viktor
Published: September 2021

This experimental study has confirmed that during thermal decomposition of polymeric waste samples at a temperature of 850 °C, without oxygen access, there is a 90 % drop in the mass of this waste with the release of a large volume of gaseous products. This feature should be taken into consideration in the engineering calculations of reaction chambers, reactors, and connecting gas pipelines. The analytical study was carried out by a method of thermodynamic analysis using the universal estimation system Astra (TERRA). It has been shown that with an increase in reaction temperature there is a change in the composition of the products of thermal destruction of polymeric waste by reducing the mole fraction of СН4 and increasing the proportion of Н2. The calorific value was calculated according to Mendeleev’s empirical formula. The experimental study (a pyrolysis-gas chromatography method) has confirmed the calculation results regarding an increase in the proportion of hydrogen in the gaseous products of destruction with an increase in process temperature. As a result, due to the lower volumetric heat of hydrogen combustion, the total caloric content of the synthesis gas obtained is significantly reduced. For the experiments, a laboratory installation of low-temperature pyrolysis of polymers with external supply of thermal energy was built, and synthesis gas was used as an energy carrier.
At the experimental-industrial installation, by a low-temperature pyrolysis method, the synthesis gas of a stable composition with a lower heat of combustion of 24.8 kJ/m3 was obtained. The reliability of the results of the proposed estimation method to the results of instrumental measurements has been shown.
Promising areas of further studies have been determined, including the optimization of processes of thermal destruction of chlorine-containing polymer waste; the effective use of hydrogen from the composition of the synthesis gas obtained.
Determination of the applicability of the tungsten-containing material as low-cost electrodes for reverse electrodialysis
Authors: Kovalenko Vadym , Kotok Valerii
Published: September 2021

Electrodialysis, especially reverse, is a promising method of water desalination, concentration of solutions, extraction of valuable components from waste and rinse water, and power generation. The main problem is the search for low-cost universal anode-cathode materials. The work aims to determine the possibility of using the VNZh90 superalloy (5 % Ni, 5 % Fe, 90 % W) and the electroplated Ni-W alloy as a universal cathode-anode material for reverse electrodialysis. The crystal structure of the Ni-W alloy was studied by X-ray diffraction analysis; the morphology was studied by scanning electron microscopy. The anodic behavior of both alloys was studied by voltammetry in 6 % HCl in a saturated NaCl solution.
The high passivity of the VNZh90 superalloy was revealed. On the repeated anodic curve, the current density of the passivation plateau decreased 2.8 times and was 37 mA/dm2. This indicates that the use of the VNZh90 superalloy is promising as a universal cathode-anode material of a reverse electrodialyzer.
The phenomenon of significant passivation for the Ni-W alloy was also revealed. The primary curve of the alloy showed two dissolution peaks and a well-defined passivation plateau. Probably, the first peak corresponded to a more active phase with a low W content. This was confirmed by the absence of the first peak on the repeated anodic curve and the identity of the passivation plateaus of the primary and repeated curves. The passivation current density was 209 mA/dm2. These data also indicate the possibility and prospects of using the electroplated Ni-W alloy as a universal cathode-anode material of a reverse electrodialyzer after optimizing the composition and deposition method of the alloy, as well as reducing the wear rate.
The effect of metal wool on the charging and discharging rate of the phase transition thermal storage material
Authors: Khliyeva Olga , Zhelezny Vitaly , Paskal Aleksey , Hlek Yana , Ivchenko Dmytro
Published: September 2021

Thermal energy storage (TES) plays an important role in solar heat power systems. The use of phase change materials (PCM) and selecting additives to increase the rate of heat accumulation is a promising way to increase the efficiency and reliability of such systems.
The objects of the study were pure paraffin wax (PW) and composite PCMs based on it (containing aluminum and copper wool of 30 and 45 μm in diameter, respectively).
An experimental setup with a cylindrical measuring cell was created, which was also considered as a model of a capsule with a thermal storage material. The rate of temperature change in the pure PW sample and samples of composite PCMs was experimentally measured. Two modes of heating and cooling were investigated: from 48 to 59 °C (mode with a phase change) and from 30 to 40 °C (mode without phase changes).
Heating time from 48 to 59 °C for the PW sample was 13 min., for the PW samples with the content of aluminum wool of 0.00588 and 0.01780 m3·m-3 − 11 and 10.5 min., for the PW samples with the content of copper wool of 0.00524 and 0.01380 m3·m-3 − 11 and 8 min., correspondingly. The minimum heating time from 30 to 40 °C was 6 min. for the sample of PW with 0.01380 m3·m-3 of copper wool in comparison with 9 min. for the sample of pure PW.
The expediency of using copper wool as an additive to thermal storage materials of PW to increase the charging and discharging rate of TES devices without significantly raising their price was confirmed. The presence of metal wool in molten PW suppresses bottom-up convective currents, so the main mechanism of heat transfer is thermal conductivity. This fact will contribute to a faster equalization of the temperature field by the height of heat storage capsules
Devising an image processing method for transport infrastructure monitoring systems
Authors: Volkov Oleksandr , Komar Mykola , Volosheniuk Dmytro
Published: September 2021

Identifying and categorizing contours in images is important in many areas of computer vision. Examples include such operational tasks solved by using unmanned aerial vehicles as dynamic monitoring of the condition of transport infrastructure, in particular road markings.
This study has established that current methods of image contour analysis do not produce clear and reliable results when solving the task of monitoring the state of road markings. Therefore, it is a relevant scientific and applied task to improve the methods and models of filtration, processing of binary images, and qualitative and meaningful separation of the boundaries of objects of interest.
To solve the task of highlighting road marking contours on images acquired from an unmanned aerial vehicle, a method has been devised that includes an operational tool for image preprocessing – a combined filter. The method has several advantages and eliminates the limitations of known methods in determining the boundaries of the location of the object of interest, by highlighting the contours of a cluster of points using histograms.
The method and procedures reported here make it possible to successfully solve problems that are largely similar to those that an expert person can face when solving intelligent tasks of processing and filtering information.
The proposed method was verified at an enterprise producing the Ukrainian unmanned aerial vehicle "Spectator" during tests of information technology of dynamic monitoring of the state of transport infrastructure.
The results could be implemented in promising intelligent control systems in the field of modeling human conscious behavior when sorting data required for the perception of environmental features
Development and experimental study of analyzer to enhance maritime safety
Authors: Nosov Pavlo , Zinchenko Serhii , Plokhikh Viktor , Popovych Ihor , Prokopchuk Yurii , Makarchuk Dmytro , Mamenko Pavlo , Moiseienko Vladyslav , Ben Andrii
Published: September 2021

On the basis of empirical experimental data, relationships were identified indicating the influence of navigators' response to such vessel control indicators as maneuverability and safety. This formed a hypothesis about a non-random connection between the navigator's actions, response and parameters of maritime transport management.
Within the framework of this hypothesis, logical-formal approaches were proposed that allow using server data of both maritime simulators and operating vessels in order to timely identify the occurrence of a critical situation with possible catastrophic consequences.
A method for processing navigation data based on the analysis of temporal zones is proposed, which made it possible to prevent manifestations of reduced efficiency of maritime transport management by 22.5 %. Based on cluster analysis and automated neural networks, it was possible to identify temporary vessel control fragments and classify them by the level of danger. At the same time, the neural network test error was only 3.1 %, and the learning error was 3.8 %, which ensures the high quality of simulation results.
The proposed approaches were tested using the Navi Trainer 5000 navigation simulator (Wärtsilä Corporation, Finland). The simulation of the system for identifying critical situations in maritime transport management made it possible to reduce the probability of catastrophic situations by 13.5 %. The use of automated artificial neural networks allowed defining critical situations in real time from the database of maritime transport management on the captain's bridge for an individual navigator.
Revealing the features of the formation of the properties of processed cheese with wild onions
Authors: Alimardanova Mariam , Tlevlessova Dinara , Bakiyeva Venera , Akpanov Zhandos
Published: September 2021

Processed cheeses belong to food products of high nutritional and biological value. Bioflavonoids, which are widespread in higher plants and have a number of unique properties, are practically not found in traditional processed cheese chunks. Quercetin is most commonly found in plant flavonoids. Most studies have confirmed the following basic biological properties of quercetin: immunostimulating effect (increases the activity of phagocytes, T- and B-lymphocytes; increases the production of antibodies, reduces the manifestations of secondary immunodeficiency, the incidence of viral infections); oncoprotective effect due to a decrease in the damaging effect of oxygen radicals on the genetic apparatus; antioxidant protection; positive effect in cardiovascular diseases, etc. The cheapest, most bioavailable and frequently used plant raw materials are onions, which also contain bioflavonoids. The article explores the use of wild onions in the creation of functional processed cheese. In connection with the spread of coronavirus infection, it is necessary to strengthen the body's immunity with the help of nutrition. The experiments carried out have established the quantitative presence of flavonoids, vitamin K in processed cheese with wild onions. Inulin and saponins were found in the composition of wild onions, which also proves the advisability of using wild onions in food. The research results on the development of a technology for a new processed cheese and a method of adding wild onion filler in different variations: fresh and in the form of a powder are presented. It was found that fresh addition of Allium odorum imparts a sharp onion aroma, and when dried it imparts a slightly chalky aroma to the final product. The positive effect of the vegetable filler on the shelf life of processed cheese has been proven.
Implementation of the method of figurative transformations to minimizing symmetric Boolean functions
Authors: Solomko Mykhailo , Tadeyev Petro , Zubyk Liudmyla , Babych Stepaniia , Mala Yuliia , Voitovych Oksana
Published: September 2021

This paper reports a study that has established the possibility of improving the effectiveness of the method of figurative transformations in order to minimize symmetrical Boolean functions in the main and polynomial bases. Prospective reserves in the analytical method were identified, such as simplification of polynomial function conjuncterms using the created equivalent transformations based on the method of inserting the same conjuncterms followed by the operation of super-gluing the variables.
The method of figurative transformations was extended to the process of minimizing the symmetrical Boolean functions with the help of algebra in terms of rules for simplifying the functions of the main and polynomial bases and developed equivalent transformations of conjuncterms. It was established that the simplification of symmetric Boolean functions by the method of figurative transformations is based on a flowchart with repetition, which is the actual truth table of the assigned function. This is a sufficient resource to minimize symmetrical Boolean functions that makes it possible to do without auxiliary objects, such as Karnaugh maps, cubes, etc.
The perfect normal form of symmetrical functions can be represented by binary matrices that would represent the terms of symmetrical Boolean functions and the OR or XOR operation for them.
The experimental study has confirmed that the method of figurative transformations that employs the 2-(n, b)-design, and 2-(n, x/b)-design combinatorial systems improves the efficiency of minimizing symmetrical Boolean functions. Compared to analogs, this makes it possible to enhance the productivity of minimizing symmetrical Boolean functions by 100‒200 %.
There are grounds to assert the possibility of improving the effectiveness of minimizing symmetrical Boolean functions in the main and polynomial bases by the method of figurative transformations. This is ensured, in particular, by using the developed equivalent transformations of polynomial function conjuncterms based on the method of inserting similar conjuncterms followed by the operation of super-gluing the variables.
Defining features in the kinetics of sodium carbonate-bicarbonate solution carbonization and the quality of the resulting sodium bicarbonate crystals
Authors: Porokhnia Mykola , Tseitlin Musii , Bukhkalo Svitlana , Panasenko Vladimir , Novozhylova Tetiana
Published: September 2021

This paper reports a study into the influence of temperature and gas consumption on the carbonization kinetics (saturation with carbon dioxide) of sodium carbonate-bicarbonate solution. The study also examined the quality and speed of crystal formation in this process. This research is predetermined by the environmental problems faced by modern enterprises that produce purified sodium bicarbonate – an insufficient degree of carbonization and, as a result, excessive air pollution with carbon dioxide, which did not participate in the reaction during the process. This study addresses these particular issues. As a result of using specialized laboratory equipment, it was found that an increase in the absorbent temperature from 79 to 85 °C leads to a decrease in the maximum degree of carbonization of the solution from 64 to 59 %. In contrast, the quality of the resulting sodium bicarbonate crystals improves but only in the range from 79 to 82 °C. With a further increase in temperature, the quality stabilizes. It is shown that the carbonization rate increases with increasing specific consumption of the absorbent (carbon dioxide) and is characterized by a negative correlation with the value of oversaturation of the absorbent in terms of NaНCO3. The quality of sodium bicarbonate crystals decreases with increasing gas velocity. Thus, it was reasonable to assume that the established dependence of the kinetics of carbonization of Na2CO3 and NaНCO3 solution on the gas velocity in the apparatus is explained by the inhibition of СО2 absorption, which is caused by the diffusion resistance of sodium bicarbonate crystallization. To improve the quality of crystals and the productivity of carbonization by reducing the supersaturation in terms of NaНCO3, it is recommended to introduce a seed crystal in the zone of binding of crystals in the carbonization columns.
Design of solid oxide structure on the composite cathode for IT-SOFC
Authors: Kamal Dianta Mustofa , Susanto Iwan , Subarkah Rahmat , Zainuri Fuad , Zainuri Belyamin , Rahmiati Tia , Permana Sulaksana , Subardi Adi , Fu Yen-Pei
Published: September 2021

Solid oxide structure of the cobalt-free composite has been exploited as a new cathode material for IT-SOFCs. The composite model system was synthesized using the metallic oxide material, which was formed by a solid-state reaction technique. The generation of the Sm0.5Sr0.25Ba0.25FeO3-δ (SSBF) model system was carried out during the sintering process. The weight loss and oxygen content were investigated by thermal gravimetric analysis (TG). Meanwhile, X-ray diffraction characterized the structure of the composite and thermal conductivity tested the conductivity properties. The results showed that the structure of the SSBF composite demonstrated the perovskite single phase leading to the structural design. The decomposition and evaporation of the constituent elements of the composite corresponded to weight losses during the constructing process. The oxygen content of the model system was 2.98 after the calcination process. The electrical conductivity value reached 2 S cm-1 at 400 °C and increases to a maximum of 7.5 S cm-1 at 710 °C. The metallic element played to generating the conductive behavior at the low temperature, while the ionic structure acted as elevated temperature. So, mixed ionic and electric conductors (MIEC) were employed comprehensively for creating the conductive properties. Based on the structure and conductivity results, the SSBF composite has a good chance as an alternative cathode material with a perovskite single phase for future TI-SOFCs applications
Economic substantiation of outsourcing the information technologies and logistic services in the intellectual and innovative activities of an enterprise
Authors: Pererva Petro , Kuchynskyi Volodymyr , Kobielieva Tetiana , Kosenko Andriy , Maslak Olga
Published: September 2021

It has been proven that modern information and logistic technologies are the most important resource of the post-industrial society. It was proved that not every enterprise has a possibility to ensure its information and logistic activities using its own capabilities, so the possibilities of using outsourcing systems are becoming especially relevant. General features of outsourcing of information technologies and logistic services were determined. The most important of them include the mandatory existence of interaction between a supplier and a customer regarding the business processes of an enterprise. It was substantiated that several important types of outsourcing are used in the area of intellectual innovation activities of enterprises: complete and partial outsourcing, outsourcing of a joint type, outsourcing of the intermediate type, outsourcing of intellectual and innovative type.
The method for synthesis of indicators of economic efficiency of outsourcing of information and logistic services of direct and indirect action for the economic evaluation of its effectiveness was proposed. This approach makes it possible to fully evaluate the benefits of outsourcing in comparison with the variant when they are implemented by an enterprise using its own capabilities. The basis of the proposed method is the ratio of indicators that reproduce the advantages obtained due to outsourcing. The implementation of this method makes it possible to ensure an important relationship between the process of development of information or logistic service and the required quality.
Studies conducted at the enterprises of the Kharkiv industrial region showed that only three out of eight studied enterprises have economic grounds for using outsourcing. From the economic point of view, it is more expedient for other enterprises to carry out information (logistic) provision of their activities using their own resources.
Economic assessment of sources of investment in the development of municipal electric transport enterprises
Authors: Illiashenko Olena , Kondratenko Natalia
Published: September 2021

The organizational and economic foundations for the formation of an investment strategy for the development of urban electric transport enterprises have been developed. The economic content of the main stages of the investment process at these enterprises has been clarified. A list of basic principles for the effective formation of the investment process has been compiled. It is proved that the enterprises of urban electric transport in Ukraine are currently unprofitable and the problems of investment support for them are extremely relevant and important.
The main directions of the development of investment activity of urban electric transport enterprises have been investigated and strategic, tactical and operational methods of its activation have been proposed. At the same time, there are three main aspects of enhancing investment activity: investment, innovation and technological.
The main provisions of the strategy of attracting investment sources by urban electric transport enterprises have been developed, which allows ensuring the required level of investment flexibility of the enterprise and independence in obtaining investment resources from various sources. The main stages of this process have been identified and substantiated, which include: the time of action, the formation of strategic goals, the algorithm for selecting and justifying the sources of investment resources and the practical implementation of the investment strategy. The practical aspects of rating sources of investment resources have been investigated, taking into account risk factors, time of use, investment prices, the ability of an enterprise and the state to influence the formation and use of investment sources. An integral indicator has been determined for each of the possible sources of investment resources, according to which the most acceptable for urban electric transport enterprises in terms of the cost of attracting and the likelihood of risk occurrence are own funds (32 points), as well as state budget funds (22 points) and local budgets (21 points). Practical recommendations on the use of the developed provisions have been formed
Combined approach architecture development to simulation modeling of systems with parallelism
Authors: Suprunenko Oksana
Published: September 2021

Paradigms and graphical-analytical tools for building simulation tools and forming the architecture of a combined approach to studying the dynamic properties of systems with parallelism are described. An extension of the formal language of Petri nets is presented, which has greater modeling power than WF nets. The properties of hierarchical Petri nets are used to synthesize a holistic model.
Discrete-event modeling and modeling of dynamic systems, which allow reflecting the quantitative and qualitative characteristics of the elements of the systems under study, served as the basis for the combined approach to the simulation of systems with parallelism. On their basis, graphic-analytical tools are proposed that provide the ability to describe the modeled system, adhering to the principle of structural similarity. They have dynamic simulations that make it easy to visually analyze and correct the model. Also, the proposed toolkit provides for the analysis of the dynamic properties of the model, which makes it possible to identify accumulated phenomena that can lead to unpredictability of the system’s functioning.
A conceptual model for the synthesis and analysis of systems with parallelism is proposed, which provides for the construction of the components of the model based on the architecture. Their step-by-step analysis and the formation of an integral model of the software system are carried out using a network representation, according to the matrix description of which invariants are calculated. The analysis of invariants allows one to obtain the dynamic properties of the model and determine the localization of structures that lead to critical situations when they are detected.
The architecture of the combined approach to the simulation of systems with parallelism is built, which provides the study of their dynamic properties to improve the reliability of the functioning of software systems
Investigation of the influence of the configuration of the fire furnace chamber on the temperature regime during the implementation of tests for fire resistance
Authors: Pozdieiev Serhii , Nizhnyk Vadym , Feshchuk Yurii , Nekora Valeriia , Nuianzin Oleksandr , Shnal Taras
Published: September 2021

The issue related to the conditions for creating the required temperature regime of fire when testing structures for fire resistance has not been studied in detail up to now. That necessitated determining the technical conditions under which it is possible to comply with the standard temperature regime of fire in the fire chamber of the furnace. The influence of the design parameters of the fire furnace chamber on the condition of compliance with the standard fire temperature regime when tested for fire resistance has been established. One of the most effective methods for examining such an impact is computer simulation. A computer model of the fire furnace was built on the basis of a comprehensive analysis and earlier work on the study of such furnaces, taking into consideration technical characteristics, in particular, geometrical parameters, fuel and air supply systems. The obtained research results are a prerequisite for scientific substantiation of the design parameters of fire furnaces and their engineering systems, which is necessary to comply with the standard temperature regime of fire in the furnace fire chamber. This makes it possible to provide the necessary conditions for testing building structures for fire resistance in compliance with the requirements of the relevant standards. The computer model constructed makes it possible to create the necessary temperature regime in the fire chamber of the furnace (in this study, the standard temperature of fire). As a result of the study, the technical parameters of the fuel supply and ventilation system were determined, which ensure compliance with the standard temperature regime in the fire chamber of the furnace. That makes it possible to build an automated complex of the testing process for fire resistance of building structures. In addition, the data obtained can be the basis for the design of such fire furnaces with the ability to comply with different fire temperature regimes without the intervention of the operator.
Analysis of intercity bus public transport safety perception modeling using conjoint
Authors: Suraji Aji , Djakfar Ludfi , Wicaksono Achmad , Marjono Marjono , Putranto Leksmono Suryo , Susilo Sugeng Hadi
Published: September 2021

Public transport safety is still an issue that needs to be studied by bureaucrats and researchers. This is because public bus accidents are still quite high. This is because many families, involved in traffic accidents, are shocked by the accident. Therefore, the problem of perception of a safe bus needs to be studied. The purpose of this study was to determine the perception model of a safe public bus. Mathematical modeling based on the parameters that have been studied was selected first. While the second objective was to determine the importance value of the parameters that are an indication of the perception of the safety of intercity bus public transportation. This research is a type of perceptual one where the data is taken from the relevant respondents. The method of data collection was carried out using a questionnaire with respondents from bus company owners, drivers, and passengers in the province of East Java, Indonesia. Respondents were asked to answer questions related to the variables of income, speed, comfort, and safety. The method of conjoint analysis is used. The first stage is the result of modeling the perception of a safe bus. Further analysis is carried out to obtain the importance value of the parameters. The result of this research is a utility model for the perception of a safe bus, which is expressed by the equation U, where the variables include income, speed, comfort, and safety. The highest level of importance is income 33.29 %, followed by the security variable with a weight of 25.39 %. This shows that the income factor is a top priority for drivers and management of bus company owners, while road safety is second only to income. In other words, respondents' perceptions are more concerned with income, while safety is still a non-priority factor.