Eastern-European Journal of Enterprise Technologies
http://journals.uran.ua/eejet
<p><span lang="EN-US">Terminology used in the title of the "Eastern-European Journal of Enterprise Technologies" - "enterprise technologies" should be read as "industrial technologies". <strong>"Eastern-European Journal of Enterprise Technologies"</strong> publishes all those best ideas from the science, which can be introduced in the industry. Since, obtaining the high-quality, competitive industrial products is based on introducing high technologies from various independent spheres of scientific researches, but united by a common end result - a finished high-technology product. Among these scientific spheres, there are engineering, power engineering and energy saving, technologies of inorganic and organic substances and materials science, information technologies and control systems. Publishing scientific papers in these directions are the main development "vectors" of the "Eastern-European Journal of Enterprise Technologies". Since, these are those directions of scientific researches, the results of which can be directly used in modern industrial production: space and aircraft industry, instrument-making industry, mechanical engineering, power engineering, chemical industry and metallurgy.</span></p><p><span lang="EN-US">Therefore, the scientists, associated with modern production, have the opportunity to participate in technology transfer to industry, publishing the results of their applied scientific researches. Industrialists, in turn, can draw scientific and practical information from the journal - each in their direction:</span></p><ul><li>specialists in management and computer science - from volumes "Applied Information Technologies and Control Systems", "Mathematics and Cybernetics - Applied Aspects";</li><li>mechanical and design engineers - from the volume "Applied Mechanics";</li><li>production engineers - from volumes "Mechanical Engineering Technology", "Applied Physics", " Materials Science", "Technology of organic and inorganic substances and the Ecology";</li><li>production and power engineers - from the volume "Energy-saving technology and equipment".</li></ul><p><span lang="EN-US">The goal of the journal is to eliminate the gap, which occurs between the rapidly emerging new scientific knowledge and their introduction in the industry, which requires much more time. Industrial enterprises are active subscribers to the "Eastern-European Journal of Enterprise Technologies", and production engineers check the practical value of those scientific and technological ideas, which are recommended for implementation by scientists-authors of the ''Eastern-European Journal of Enterprise Technologies".</span></p><p><span lang="EN-US">The objective of the journal in achieving the goal is forming a "scientific component" of modern technologies transfer from science to industry. Therefore, in the papers, published in the journal, the emphasis is placed on both scientific novelty, and practical value.</span></p>en-US<p>Our journal abides by the CREATIVE COMMONS copyright rights and permissions for open access journals.</p><p>Authors, who are published in this journal, agree to the following conditions:</p><p>1. The authors reserve the right to authorship of the work and pass the first publication right of this work to the journal under the terms of a Creative Commons Attribution License, which allows others to freely distribute the published research with the obligatory reference to the authors of the original work and the first publication of the work in this journal.</p><p> 2. The authors have the right to conclude separate supplement agreements that relate to non-exclusive work distribution in the form in which it has been published by the journal (for example, to upload the work to the online storage of the journal or publish it as part of a monograph), provided that the reference to the first publication of the work in this journal is included.</p>selezniova.alina@gmail.com (Makarenko Alina)selezniova.alina@gmail.com (Makarenko Alina)Mon, 30 Apr 2018 16:10:27 +0300OJS 2.4.4.1http://blogs.law.harvard.edu/tech/rss60Development of a multicriteria model for making decisions on the location of solid waste landfills
http://journals.uran.ua/eejet/article/view/129287
<p class="a">We have developed a structure of the multi-criteria model of decision making related to determine optimal sites for the location of solid waste landfills (using the south of Odessa oblast as an example). A special feature of the model is the integration of GIS and the multi-criteria methods of decision-making. Based on the created raster criteria maps in the GIS geodatabase and expert estimation of the significance of criteria, we ranked alternatives according to the degree of suitability. A multilevel hierarchical decision-making structure includes three groups of criteria: environmental, physical, and socio-economic; it takes into consideration the state building requirements to the construction of SW polygons. Such an approach provides for the acceptability of results of the analysis by most stakeholders.</p><p class="a">The simulation is performed for the three scenarios that imply the aggregation of layers of criteria into a combined map of suitability using Boolean logic, fuzzy logic, and a combination of methods of weighted overlay and a fuzzy analysis of hierarchies. To account for the uncertainty of original information and subjectivity in expert assessments, we employed an apparatus of fuzzy logic. Piecewise-linear membership functions of the fuzzy set are proposed for the standardization of criteria. We calculated weights of criteria using a modified method of the analysis of hierarchies, in which we used linguistic variables represented by triangular fuzzy numbers to perform the paired comparison of criteria significance.</p><p class="a">The results of the simulation show that the use of operations of a fuzzy intersection or a fuzzy combination in order to aggregate a combined suitability map can lead to errors related to the underestimation or overestimation of alternatives. The most acceptable method is a weighted linear combination, or the operation of fuzzy geometric averaging, in cases when it is difficult or impossible to determine the weight of criteria.</p>Svitlana Kuznichenko, Ludmila Kovalenko, Iryna Buchynska, Yurii Gunchenkohttp://journals.uran.ua/eejet/article/view/129287Tue, 24 Apr 2018 12:23:18 +0300Prediction of specific electrical resistivity of polymeric composites based on carbon fabrics
http://journals.uran.ua/eejet/article/view/129062
<p class="a">We have proposed an improved approach to forecasting electrical resistivity of composite materials based on carbon fabrics by using a finite element method that takes into consideration a deformation of the reinforcing material during molding. Electrical characteristics of homogenized reinforcing fibers are determined by using known dependences for unidirectional composites. Based on the developed approach, we calculated values of electrical resistivity of composite materials based on the carbon fabric of twilled weaving and the weft-knitted carbon fabric. To account for a change in the thickness of the weft-knitted carbon fabric during molding, we simulated its deformation under the action of vacuum pressure. The obtained calculated values of electrical resistivity of the examined materials are in good agreement with the results of experimental study. Divergence between the calculated and experimental results for a material based on the carbon fabric of twilled weaving is 10 %. For materials based on the weft-knitted carbon fabric, divergence is 11 % towards the weft and 32 % in the direction of the base of the fabric.</p><p class="a">Given that the volumetric fiber content in a material from the weft-knitted carbon fabric was determined based on the results of modeling its deformation at molding, as well as the results of similar studies, reliability of the simulation can be considered quite satisfactory. The proposed approach could be applied when choosing a rational scheme for weaving a fabric in order to estimate specific resistivity in the absence of information about volumetric fiber content and the actual structure of the material after its fabrication.</p>Vadym Stavychenko, Svitlana Purhina, Pavlo Shestakovhttp://journals.uran.ua/eejet/article/view/129062Fri, 20 Apr 2018 15:37:25 +0300Effect of heat treatment and cryogenics on hardness of ductile cast iron microstructure (FCD50)
http://journals.uran.ua/eejet/article/view/129013
<p>The results of researches of possibilities of increasing the mechanical properties of pig iron with ball-bearing graphite of brand FCD-50 by the combined heat treatment are described. The scheme of multistage heat treatment, the characteristic feature of which is the operation of cooling in liquid nitrogen, is proposed. The use of such a scheme allows for increased HRC hardness characteristics. The study of the microstructure of cast iron treated with this scheme has proved the efficiency of the cryogenic heat treatment stage and determined its rational regimes.</p><p>To match or approximate the properties of steel, the mechanical properties of this ductile cast iron 50 (FCD-50) must be enhanced by methods such as ACTDI (austemper cryogenic and temper Ductile Iron). In this procedure, the FCD-50 specimen is inserted into the electric kitchen heater at 350 °C (room temperature), heated to 600 °C and held at this temperature for 45 minutes. Next, the specimen is heated to 900 °C and held at this temperature for 1 hour (temperature austenisation). Then, the specimen is placed in furnace 2 at 3,000 °C for 45 minutes (austempering process). The specimen subsequently is cooled in liquid nitrogen. In this study, additional specimens were obtained for hardness and microstructure tests. The as-cast test yielded a hardness value of 18.39 HRC. In the hardness test for the ACTDI process, 12 hours of submersion yielded the highest hardness result of 24.25 HRC. In terms of the changes in microstructure after soaking changes, the amount of perlite present in the specimen was greater than that of ferrite, and the arrangement of graphite nodules was better than that of the as-cast material.</p>Suriasnyah Sabarudin, Pratikto Pratikto, Agus Suprapto, Yudy Surya Irawanhttp://journals.uran.ua/eejet/article/view/129013Fri, 20 Apr 2018 11:20:39 +0300The effect of external magnetic flux field in the QTS weldment on the change of fatigue crack propagation behaviors
http://journals.uran.ua/eejet/article/view/122919
<p class="a">This investigation discusses fatigue crack propagation behaviors on the welded joint of Hot Rolled Quench Tempered Steel (QTS) in which during welding process the fusion zone of the joint was subjected to magnetic flux field. The QTS weldability is not really excellent due to the change of microstructure into tempered martensite, and the possibility of microcrack defect on the welding area is still high. The purpose of the investigation is to know the effect of External Magnetic Flux (EMF) field during welding process on fatigue crack propagation behaviors. The external magnetic flux is applied transversely from two sides of the workpiece using a DC powered solenoid of 0, 3, 6, 9 and 15 Amperes. The effect of EMF is more sensitive to decrease the tensile strength and the fatigue crack propagation rate of the weld area. The result shows that the electromagnetic force on the weld pool increases. It causes the liquid metal circulation rate to increase and welding defects to decrease. This indicates that the liquid metal and filler metal are easily mixed, the release of gas from liquid metal to surface before solidification easily happens. The finding shows that the effect of EMF is more efficient.</p>Sugiarto Sugiarto, Rudy Soenoko, Anindito Purnowidodo, Yudy Surya Irawanhttp://journals.uran.ua/eejet/article/view/122919Thu, 19 Apr 2018 17:27:32 +0300Application of information technologies for the optimization of itinerary when delivering cargo by automobile transport
http://journals.uran.ua/eejet/article/view/128907
<p>We have proven the applicability of modern tools of information technologies to solve a traveling salesman problem using a combinatorial method and a transport problem, which is stated in the form of a road transport network, by the simplex method. The obtained results of solving these problems were employed when making up the optimum itinerary of cargo delivery along international routes. The methods proposed could solve transportation problems of any dimensionality, both balanced and non-balanced in terms of cargo transportation volumes.</p><p>Advantageous geographical position of Ukraine and the existence of strong transportation infrastructure is an important basis to form robust economy of Ukraine. The potential of Ukraine in the international market of transportation services is estimated rather high by experts. Based on the Logistics Performance Index, calculated by the World Bank, Ukraine ranks 61, which is the best indicator among all CIS countries. Development of optimal itinerary of cargo delivery along international routes is predetermined by several factors, the main among them being the high cost of transportation services and tough competition between domestic and foreign freight carriers.</p><p class="231">The application of information technologies in transportation services opens up new prospects for improving the efficiency of freight transportation. Optimization of cargo delivery schemes is one of the key tasks of transport logistics. Combined use of the described methods for solving open network transportation problems, specifically a method of finding the shortest routes in a road transport network and methods for reducing the unbalanced cargo transportation to the balanced form, makes it possible to obtain considerable synergistical, economical, and organizational-technological effects.</p>Georgii Prokudin, Оlexiy Chupaylenko, Olexiy Dudnik, Oleksii Prokudin, Alena Dudnik, Vitaliy Svatkohttp://journals.uran.ua/eejet/article/view/128907Thu, 19 Apr 2018 11:45:14 +0300Development of a method for determining the area of operation of unmanned vehicles formation by using the graph theory
http://journals.uran.ua/eejet/article/view/128745
<p class="a">The results of research into influence of modification of the topology of a heterogeneous formation of unmanned vehicles on the area, covered by this formation are presented. We proposed an approach, according to which the method for modeling the structure of complex technical systems is applied to describe the behavior of unmanned vehicles’ formation. The changes in topology and in the covered area as a result of unmanned vehicles’ rearrangement within a formation were considered.</p><p class="a">Based on the result of present study, a method for determining the area of unmanned vehicles’ formation operation involving the graph theory was proposed. Formation of the loaded directed graphs that correspond to the main (star, ring, bus) and mixed (hierarchical star with a bus, hierarchical star with a ring) formation topologies was considered in detail. The adjacency matrix and the loading matrix for the topology "hierarchical star" were analyzed.</p><p class="a">In addition, the study conducted allows us to conclude that to ensure a full coverage of a certain territory, the mathematical model of the structure of a dynamic system must be characterized by a random number of vertices that correspond to a variable number of unmanned vehicle in a formation. Various technical characteristics of unmanned vehicles, which belong to different classes by weight or control type, must be considered into account when constructing the matrix of graph loading. Calculation of the area, covered by an unmanned vehicles’ formation, is performed as calculation of the area of polygons, assigned by their vertices, using the interpolation concept to count the intermediate values of magnitudes by a discrete set of known coordinate values. Calculation of the formation area is based on the ranges, within which sustainable communication between the drones of different models is provided.</p><p class="a">Partition of the loading matrix into subordination units makes it possible to decrease computational complexity and thereby prolong operation of a formation. Application of this approach will allow us to plan more effectively the time and the number of drones in a formation, necessary for covering the territory of the specified size.</p>Iryna Zhuravska, Inessa Kulakovska, Maksym Musiyenkohttp://journals.uran.ua/eejet/article/view/128745Tue, 17 Apr 2018 14:16:55 +0300Development of method of multifactor classification of transport and logistic processes
http://journals.uran.ua/eejet/article/view/128679
<p class="a">A method of classification of a set of objects and/or processes in transport and logistics systems on the basis of a multifactor analysis was proposed.</p><p class="a">Combination of the methods of statistical and factor analysis, the systems hierarchy analysis method and modern methods of logistic analysis has enabled formation of a complex classification model. A three-stage algorithm was proposed for solving multifactor problems of classification in the fields of transport and logistics and the theory of organization of cargo transportation. At the first stage, the factor influence is investigated based on the chosen criterion. At the second stage, a comprehensive analytical indicator is created that characterizes the influence of factors on the objects under study and is based on the systemic hierarchy analysis method. The use of the hierarchy analysis method enables both use of factual data based on a thorough statistical analysis and involvement of experts in solving multifactorial decision-making problems. The use of modern logistic analysis methods in the third stage makes it possible to reasonably divide classification objects in the transport and logistics systems among various numbers of dynamic classes. At this stage, it is also possible to involve experts in the formation of boundaries of classes. The model was implemented using the Symbolic Computing Package in the Maple-7 and the Microsoft Excel environments.</p><p class="a">Classification of Ukraine's trading partner countries by indicators of international turnover of certain groups of goods which can be transported in universal containers according to the Ukrainian foreign economic activity classifier (UFEAC) was made. Through simulation, the set of partner countries in foreign trade was divided into three classes. Classification of Ukraine’s partner countries by indicators of international turnover of certain groups of goods which can be transported in universal containers in accordance with the Ukraine’s foreign economic activity classifier (UFEAC) has allowed us to divide a set of partner countries in foreign trade into three classes. The classification results are in good agreement with the classic ABC analysis. Classification of countries by the criterion of specific value of goods flows has allowed us to divide the set of countries under study into two classes. This is explained by the fact that classification was made for a set of all partner countries in the first example and twenty countries with the largest turnover were previously selected in the second example.</p><p class="a">Application of the proposed method of multifactor classification ensures dividing the objects of classification, in general, among different numbers of groups. At the same time, the boundaries of dynamic classes which are formed on the basis of a comprehensive assessment of the factor influence and depend on the concrete formulation of the problem and the criteria taken into account.</p><p class="a">The proposed classification method can be used in transport, logistics, customs and brokerage enterprises, as it allows for planning and controlling supply of goods to varying degrees of detail and apply appropriate strategies.</p><p class="a">Further development and improvement of this study is possible in the direction of using intelligent systems and algorithms to solve problems of multifactor analysis of transport and logistics systems.</p>Arkadii Bosov, Nataliya Khalipova, Iryna Prohoniuk, Violetta Kuzmenko, Viktor Duhanets, Inna Shevchenkohttp://journals.uran.ua/eejet/article/view/128679Mon, 16 Apr 2018 17:56:24 +0300Analysis of energy of internal waves in a threelayer semiinfinite hydrodynamic system
http://journals.uran.ua/eejet/article/view/128641
<p class="a">Energy characteristics of waves propagation along the contact surfaces in a hydrodynamics system "liquid half-space – layer –layer with a rigid lid" are explored. Based on the solutions of first approximation to a weakly non-linear model, the integral relations for wave motion energy in each layer and for the total energy of the system were obtained. An analysis of energy of wave processes revealed that an increase in wave number causes a decrease in energy of wave motion of the upper layers, and energy of wave motion of the lower half-space at some values of wave number reaches extreme values. In this case, total energy of the system is descending in nature and rather quickly approaches its limit value.</p>The numerical values of energy for three different cases of propagation of progressive waves were obtained: only along the upper contact surface, only along the lower contact surface, along both surfaces simultaneously. Comparison of the obtained values of energy revealed that in the case of waves propagation along both contact surfaces simultaneously, the total energy of the system is close to the sum of energies of the system at waves propagation along one of the surfacesOlga Avramenko, Maria Lunyovahttp://journals.uran.ua/eejet/article/view/128641Mon, 16 Apr 2018 17:55:05 +0300Numerical simulation of two-dimensional problems of creep crack growth with material damage consideration
http://journals.uran.ua/eejet/article/view/119727
<p>Approach for numerical simulation of the process of the creep crack growth taking into account the hidden material damage is proposed. The approach is based on the application of finite element creep modeling, accompanied by damage. For calculations, the FEM Creep software package is used. Using the proposed algorithm for rebuilding the grid with the removal of the destroyed elements, the current picture of deformation and fracture is analyzed. This takes into account the growing level of damage during the crack motion in each element. Numerical fracture simulation data are used to determine the constants in the differential creep fracture propagation equation. As an example, the creep fracture of planar specimens with sharp notches in their plane is considered. The material of the specimens is a high-temperature nickel-based alloy EI 867 at a temperature of 950 °C. Calculations are carried out for different values of the load. For different times, finite element grids with remote elements are shown. Graphs of the dependence of crack length on time are built. Comparison of numerical and calculated data obtained with the motion equation of a crack shows their acceptable coincidence. The possibility of using the proposed approach for obtaining constants in the equation of crack motion as an alternative to the existing experimental one is discussed.</p>Dmytro Breslavsky, Alyona Kozlyuk, Oksana Tatarinovahttp://journals.uran.ua/eejet/article/view/119727Mon, 16 Apr 2018 17:28:24 +0300Investigation of the work of the road construction at the sites by pipe drenes from materials of different origin
http://journals.uran.ua/eejet/article/view/126512
<p>The paper reports research into operation of road structures with tubular drains made from materials with different physical-mechanical properties, which makes it possible to identify basic factors that affect operational conditions under the influence of own mass and the rated load from rolling stock in accordance with the building norms of Ukraine. Non-standard road structures were simulated in the SCAD environment. The results of numerical simulation allowed us to derive diagrams of normal stresses and deformations of structural layers in road surfacing, as well as in the body of tubular drains. The calculations were performed both for the standard and the actual compaction of material used as a trench backfill, for a PVC pipe and a concrete pipe.</p><p>Consideration of tubular openings in solid layered road structures made it possible to estimate the actual stressed-deformed state at the sections of roads that require control over a water-heat mode. The proposed method of study enables the selection of individual design-structural parameters for drainages of shallow laying for general-purpose public roads of different technical categories as opposed to the standard approaches implied by the building regulations of Ukraine.</p>Оlena Slavinska, Vyacheslav Savenko, Andrey Bubela, Andrey Yaremovhttp://journals.uran.ua/eejet/article/view/126512Mon, 16 Apr 2018 17:22:46 +0300Development of new technological solutions for recovery of heavy nonferrous metals from technogenic waste of electroplating plants and sludge of water treatment systems
http://journals.uran.ua/eejet/article/view/128532
<p>In galvanic cakes and municipal wastewater sludge, there are significant amounts of heavy non-ferrous metals, which are classified as hazard class I ecotoxicants and are currently being disposed. The existing methods of toxic waste processing do not provide for the selection and efficient recovery of valuable components. However, the cost of non-ferrous and precious metals and their industrial content in these types of technogenic waste allow justifying the payback and profitability of their industrial processing.</p><p>Based on the laboratory and large-scale laboratory experiments, flow diagrams of processing of galvanic cakes and wastewater sludge are proposed. The calculated kinetic and thermodynamic characteristics (activation energy, time of complete dissolution, Gibbs free energy value), the recovery parameters of heavy non-ferrous metals (ε<sub>Cu</sub>=99.5 %, ε<sub>Ni</sub>=99.5 %, ε<sub>Zn</sub>=99.9 %) indicate the possibility of industrial implementation of the given flow diagrams. Dependencies of copper recovery on temperature and leaching time are presented. The obtained results allow speaking about the kinetic limitation of the process of galvanic cake leaching (Е<sub>Cu</sub>=15.7 kJ/mol) and demonstrate the possibility of conducting the process at low temperatures (t=40 <sup>o</sup>C), which leads to lower energy consumption.</p><p>The advantage of the proposed options of processing of galvanic cakes and wastewater sludge is the presence of commercial equipment, the use of traditional hydrometallurgical processes, availability and low cost of reactants, short payback periods and anthropogenic load reduction.</p>Mikhail Barkan, Anton Kornevhttp://journals.uran.ua/eejet/article/view/128532Thu, 12 Apr 2018 14:10:18 +0300Development of principles and methods for calculation of direct current hybrid contactors
http://journals.uran.ua/eejet/article/view/128495
<p>The study showed that we can implement the principle of current control of the main circuit of a hybrid DC contactor by introduction of a small-size transformer of current into it. It has two primary windings, the first of which is connected to the first pole in succession with the main contact, the second one ‒ in series with a semiconductor switch, which shunts this contact in opposition to the first, and one secondary power supply.</p><p>The study determined peculiarities of the processes of current flowing from the circuit of the main contacts, the commutation of a current transformer, the charging of a commutation condenser for locking of a semiconductor switch. The study showed that a magnetic wire conductor of a transformer is saturated and a control circuit is deenergized in a switched-on state. When a contactor is switched off, the charge of a commutation condenser capacitor goes due to a direct current under an action of EMF, which occurs on the secondary winding of a transformer during its re-magnetization in the opposite direction by current flowing in a shunting circuit. At the same time, at the given values of a cross section of a magnetic conductor and capacity of a condenser, a voltage level to which it is charged, does not depend on the number of turns of the secondary winding, but it is proportional to a square root of commutated current. The time of its charge under the same conditions is proportional to the number of turns of the secondary winding. This makes it possible to approach reasonably definition of parameters of elements that provide reliable locking of semiconductor switchers.</p>The study showed that the proposed hybrid contactors, due to introduction of circuit current control, have properties that enhance their competitiveness compared to the existing ones. Specifically, they increased reliability, they do not need a power supply from an additional power source, they exclude standard drivers, they show minimized energy consumption. Thus, the application aspect of a use of the obtained scientific result is the possibility of creation of competitive reliable hybrid DC contactors for voltage up to 1,000 V and currents of 100‒630 AAnatoly Soskov, Nataliya Sabalaeva, Yana Forkun, Marina Glebovahttp://journals.uran.ua/eejet/article/view/128495Thu, 12 Apr 2018 14:04:07 +0300Study of the influence of oxidizing parameters on the composition and morphology of Al2O3•CoOx coatings on AL25 alloy
http://journals.uran.ua/eejet/article/view/128457
<p>The influence of operating parameters of plasma-electrolytic oxidation in diphosphate cobalt-containing electrolyte on the process of formation of oxide coatings on alumosilicon alloy AL25 (GOST 1583) was studied. It was shown that inclusion of cobalt into the composition of surface oxide layers leads to a change of morphology and topography of the surface. Variation of current density and PEO time allows flexible control of the process of incorporation of the catalytic component into the matrix of oxide of basic metal. It was shown that at an increase in oxidation time, cobalt content in the surface oxide layer increases.</p><p>The rational mode of plasma-electrolytic treatment of piston alloy in diphosphate electrolyte for obtaining oxide coatings, enriched with cobalt, was substantiated. It is advisable to perform formation of PEO-coatings on AL25 with developed globular-mosaic surface, maximum cobalt content, with minimizing impurities in the range of current densities of 3–5 A/dm<sup>2</sup> within 20–40 min. The obtained cobalt-containing oxide coatings can be used in the air and water purification systems, specifically, for intracylinder catalysis of gas emissions of internal combustion engines.</p>Ann Karakurkchi, Mykola Sakhnenko, Maryna Ved'http://journals.uran.ua/eejet/article/view/128457Wed, 11 Apr 2018 16:33:35 +0300Development of a technology for absorbing screening of command posts with electronic equipment
http://journals.uran.ua/eejet/article/view/128423
<p>The problem of creation of a technology for effective protection of rooms of control points with electronic equipment against powerful intentional and industrial interferences was studied. Development of ray weapons is a new challenge to electronic equipment safety by the use of modern powerful electromagnetic weaponry. Absence of theoretical recommendations in the conditions of growing practical needs causes the relevance of this problem solution.</p><p>As a result of theoretical and experimental studies, rational ways for solution of the problem related to the necessity of absorption of the field energy in a wide frequency range at the level of 40...50 dB were substantiated while the level of absorption known from publications is 10...20 dB.</p><p>The basis for solving this problem is a significant improvement of the technology for preparation of a filler with necessary electromagnetic properties. This is an electrically conductive ferrite-ferrite compound with a structure of spinel of inverse type which has the commensurate levels of relative dielectric and magnetic permeability and electrical conductivity of (103...104) S/m. These properties of the filler will contribute to the satisfaction of generally contradictory requirements. Such are the requirements for reducing the field energy reflection from the surface of the radiation absorbing coating of the room and the requirements for increasing linear energy absorption by coating (12...15 dB/mm). Therefore, the proposed 4 mm thick absorbing Sorel cement tiles with the proposed filler provide absorption of field energy in a wide frequency band at a level of 40...50 dB due to their polymerization filling.</p><p>The choice of the aforementioned binder base for the filler is justified because significant levels of thermal stability of the base are required. In principle, it is also necessary to improve the technology of highly concentrated filling of the solid, heat-resistant polymer base for the radiation absorbing coating, which effectively protects hardware of the command post from contemporary ray weapons.</p><p>Existing organic polymer bases for the required coating have a limited ecological purity and working temperature not exceeding 250...300 <sup>o</sup>C.</p><p>Therefore, it is expedient to use an environmentally friendly inorganic polymer in a form of Sorel cement with significantly higher thermal stability. That is why the technology of screening rooms by covering their inner surface with absorbing Sorel cement tiles was proposed. Once the filler is prepared, pre-filling of the aqueous solution of cement ingredients with dispersed filler as a field energy converter is made. After solidification of the Sorel cement tiles and covering the surface of the room, energy of interfering electromagnetic fields falling on the coating converts into heat energy.</p>The necessary hardware screening at a level of 40...50 dB is provided by the following technology stages. First, thermochemical synthesis of conductive ferrite oxide of transition metals with a structure of spinel of inverse type is carried out at a temperature above 600 <sup>o</sup>C. Secondly, vibrational polymerization concentrated filling of the base mixture of the magnesium oxide and saturated aqueous solution of magnesium chloride is realized without the loss of strength of the tiles after their solidification. The tiles are solidified at room temperature for 15 to 17 hoursBoris Demianchuk, Aleksander Matsko, Natalia Natalia Kolesnychenko, Vladimir Diachenko, Wiacheslav Obertashttp://journals.uran.ua/eejet/article/view/128423Wed, 11 Apr 2018 16:31:25 +0300Exploiting the knowledge engineering paradigms for designing smart learning systems
http://journals.uran.ua/eejet/article/view/128410
<p class="a">Knowledge engineering (KE) is a subarea of artificial intelligence (AI). Recently, KE paradigms have become more widespread within the fields of smart education and learning. Developing of Smart learning Systems (SLS) is very difficult from the technological perspective and a challenging task. In this paper, three KE paradigms, namely: case-based reasoning, data mining, and intelligent agents are discussed. This article demonstrates how SLS can take advantage of the innovative KE paradigms. Therefore, the paper addresses the pros of such smart computing approaches for the industry of SLS. Moreover, we concentrate our discussion on the challenges faced by knowledge engineers and software developers in developing and deploying efficient and robust SLS. Overall, this study introduces the reader the KE techniques, approaches and algorithms currently in use and the open research issues in designing the smart learning systems.</p>Abdel Badeeh Mohamed M. Salem, Silvia Parushevahttp://journals.uran.ua/eejet/article/view/128410Wed, 11 Apr 2018 16:30:09 +0300Modeling a thermal conductivity process under the action of flame on the wall of fireretardant reed
http://journals.uran.ua/eejet/article/view/128316
<p>Creating environmentally friendly flame-retardant materials for natural inflammable roof structures will make it possible to control the processes of thermal stability and physical-chemical properties of a protective coating over its life cycle. There is therefore a need to study conditions for the formation of a thermal conductivity barrier and for the establishment of a mechanism that inhibits heat transfer to the material. It was experimentally determined that reed, non-treated with a flame-retardant agent, was ignited under the action of burner in 5 seconds, with the flame spreading throughout the entire surface, which resulted in its complete burning and the loss of mass. The study that we conducted into the influence of a coating on the transfer processes of a high-temperature flame to a material, established the fire protection process mechanisms, which imply the inhibition of such an action. It was proven that this process includes the decomposition of flame retardants under the action of temperature, with heat absorption and release of incombustible gases, the formation of ash-like products at the surface of a natural combustible material, as well as thermal insulation. That made it possible to determine conditions to protect reed from fire by forming a barrier to thermal conductivity. Experimental study has confirmed that a sample of fire-retardant reed withstood a thermal influence; the action of a heat flow lead to the swelling of the impregnation and the coating, which lasted for 120 seconds. We estimated the maximum possible penetration of temperature through the thickness of a coating and established that when reed, protected by the impregnating composition, was exposed to a flame of the burner, temperature at the inner surface was less than 147 °C with the mass loss not exceeding 2.9 %. Even greater efficiency was demonstrated by samples that were treated with the coating; the temperature did not exceed 140 °C, with a 2.5% mass loss. We also established that the coefficient of thermal conductivity, when protected from fire, reaches 1.6 W/(m∙°C) for the impregnating composition, and 1.2 W/(m∙°C) for the coating, respectively.</p>Yuriy Tsapko, Аleksii Tsapkohttp://journals.uran.ua/eejet/article/view/128316Tue, 10 Apr 2018 16:59:13 +0300Generalization of one algorithm for constructing recurrent splines
http://journals.uran.ua/eejet/article/view/128312
<p class="a">We have analyzed two algorithms, close in composition, for constructing a smoothing spline, which imply a change only in the last link of the spline when new experimental data arrive. The main feature of the N. D. Dicoussar algorithm is the form of a polynomial representation in order to describe a link of the spline. It is shown that a given polynomial is one of the hierarchical form of the Hermitian polynomial.</p><p class="a">We have proposed a modification to the D. A. Silaev algorithm for constructing a smoothing spline with different orders of smoothness: from zero to the second, aimed at enhancing the stability of this algorithm. To this end, we substantiated recommendations related to the form of polynomials representation, which describe the links of splines of the specified form. For this purpose, we estimated conditionality of matrices used in the algorithm. For the spline of zero-order smoothness, the most advisable is to apply a polynomial in the N. D. Dicoussar form, and for splines with higher orders of smoothness of joining the links, it is appropriate to use different forms of the Hermitian polynomials.</p>Based on computational examples, a possibility was demonstrated to generalize the D. A. Silaev algorithm to construct a spline with links of various lengths, which is determined by the rate of change in the examined parameter. That makes it possible to reduce the volume of information that contains a description of the spline itself, and to prevent such a widespread shortcoming of approximation when using polynomials as parasitic oscillations. It was shown as well that in the presence of significant measurement errors in experimental data there may occur a need to decrease the length of the spline's link (compared to that derived by the D. A. Silaev rule) in order to provide the spline with a property of robustnessGalina Tuluchenko, Gennadii Virchenko, Galyna Getun, Viacheslav Martynov, Mykola Tymofieievhttp://journals.uran.ua/eejet/article/view/128312Tue, 10 Apr 2018 16:58:05 +0300Tools for forecasting and optimizing the tuning parameter of the lowspeed engine for designing a ship with the kite
http://journals.uran.ua/eejet/article/view/128302
<p>The developed simulation (stochastic) mathematical model for calculating fuel consumption of the main low-speed engine of a transport ship with a kite is proposed. The peculiarity of the model is the use of a number of initial probabilistic quantities such as wave height, wind speed, in the form of inverse integral distribution functions of their values. This makes it possible, using a generator of uniformly distributed pseudo-random numbers, to compute the arrays of possible values of the total fuel consumption of the main engine for the entire future operation and to determine the expected value of consumption. Such a simulation model with a pseudo-random number generator serves as a tool for comparing the fuel consumption of the alternative main engines, differing in the value of the “internal combustion engine – turbocharger” matching parameter. The minimum value of the total fuel consumption corresponds to the optimum value of the matching parameter.</p><p>Due to the simulation mathematical model, the influence of the “internal combustion engine – turbocharger” matching parameter on the total fuel consumption for the 25-year operation period of the tanker with a deadweight of 26,470 t is investigated with the help of a computer. Its propulsion is provided by the 6S50ME-C7 engine and SkySails 640 m<sup>2</sup> kite switched if the winds are favorable. It is found that the optimum matching parameter corresponds to a point on the propeller curve of the engine with a load coordinate of 60.5 % of the rated value. This refers to a round transatlantic voyage in the Northern Atlantic, mainly in temperate latitudes, with prevailing westerlies and northeast trade winds. Fuel economy in the liner shipping at speeds of about 13.5 knots for these conditions due to the use of the kite is 21 %, from the optimization of the mentioned parameter 3.4 % and in general 24.4 %. At the price of fuel for ship diesel engines of USD 322/ton, the expected value of fuel consumption reduction for the medium-range tanker for the specified period is USD 2,029.000 or USD 81,000/year.</p>Vladimir Shostak, Alena Kisarovahttp://journals.uran.ua/eejet/article/view/128302Tue, 10 Apr 2018 16:56:55 +0300Application of piecewisecubic functions for constructing a Bezier type curve of C1 smoothness
http://journals.uran.ua/eejet/article/view/128284
<p class="a">We have proposed and implemented a new method for constructing a spline curve of third degree, which possesses the properties of both a cubic spline and the Bezier curve. Similar to building the Bezier curves, control points are assigned, whose position affects the shape of the curve. In the proposed approach, the sections of the straight line that connect control points are tangent to the curve that is constructed. The location of touch points can be different, allowing the construction of different curves for one set of control points. A special feature of the proposed method is assigning, in abscissa of control points, some unknown spline values that are found from conditions for the continuity of the first derivatives of the curve at these points. Finding the coefficients of polynomials that make up the curve comes down to solving a system of linear equations with a three-diagonal matrix. The built curve is a piecewise-cubic function, continuous along with its first derivative throughout the entire interval. Conditions were found for any set of control points in the form of inequalities, which parameters of the curve must meet, at which the curve does exists and it is unique. These conditions follow from the requirement for a diagonal advantage of the matrix of the system for determining coefficients of the curve. A series of computational experiments were performed, which showed that the curve effectively inherits the shape assigned by control points. Similar to the Bezier curves, the proposed curve could be used in computer graphics systems and computer systems for technical design, specifically for the creation of fonts, drawings of parts, elements of transportation vehicles' bodies, etc.</p>Oleg Stelia, Leonid Potapenko, Ihor Sirenkohttp://journals.uran.ua/eejet/article/view/128284Tue, 10 Apr 2018 16:55:43 +0300Adaptive control over nonlinear objects using the robust neural network FCMAC
http://journals.uran.ua/eejet/article/view/128270
The paper explores issues related to the application of artificial neural networks (ANN) when solving the problems on identification and control of nonlinear dynamic systems. We have investigated characteristics of the network, which is a result of the application of the apparatus of fuzzy logic in a classical СМАС neural network, which is titled FCMAC ‒ Fuzzy Cerebral Model Arithmetic Computer. We studied influence of the form of receptive fields of associative neurons on the accuracy of identification and control; various information hashing algorithms that make it possible to reduce the amount of memory required for the implementation of a network; robust learning algorithms are proposed allowing the use of a network in systems with strong perturbations. It is shown that the FСМАС network, when selecting appropriate membership functions, can be applied in order to synthesize indirect control systems with and without a reference model; it is more efficient to use it in control systems with the reference model. This sharply reduces the quantity of training pairs and simplifies the coding due to the narrower range of the applied values of input signals. The results obtained are confirmed by simulation modeling of the processes of identification of and control over nonlinear dynamical systemsOleg Rudenko, Oleksandr Bezsonov, Oleh Lebedievhttp://journals.uran.ua/eejet/article/view/128270Tue, 10 Apr 2018 16:54:41 +0300