Bezrodny M.K., Prytula N.O.
Optimum Operation of the Heat Pump in the Low-Temperature Heating Systems Using the Ground Heat
P. 7–12.
Fig. 4. Refs.: 13 titles.
The paper under scrutiny studies optimum operation of the heat pump in low-temperature heating systems utilizing the ground heat. When using the ground heat in the heat pump heating system there is an optimal degree of cooling brine in the evaporator of the heat pump corresponding to the minimum total cost of electricity for heat pump heating system as a whole. Through experiments conducted, we determine that the optimal degree of cooling brine in the evaporator of the heat pump largely depends on the constants A complex. However, it poorly depends on the calculated temperature of heat carrier for heating in the range of 30–50 °С, brine temperature at the inlet of the evaporator in the range of 2–5 °С and the ambient temperature. Finally, we obtain a formula for determining the optimal degree of cooling brine in the evaporator, depending on the constants A complex.
Galchenko V.V., Kovalchuk V.S.
Comparative Analysis of Data Preparation with Consideration of Distribution of Coolant Temperature on Cartridge Radius and Using its Average Value
P. 13–18.
Fig. 8. Tabl. 1. Refs.: 9 titles.
Influence of account of distributing of temperature of teplonosiya is studied on the radius of TVZ on the sizes of macroscopic sections of co-operation by the software products of Solidworks and Wimsd-5b. The macroscopic sections of co-operation were determined depending on composition of fuel, his burning down, position of organs of adjusting, closeness of teplonosiya, temperature of teplonosiya, temperature of fuel and concentration of liquid absorber. The method of dataorigination consisted in oserednenni of the indicated parameters of fuel and teplonosiya on the cut of TVZ. The conducted researches rotined that the account of distributing of temperature of teplonosiya on the cut of TVZ substantially did not have influenced on the homogenized macroscopic descriptions of the system in the “thermal” area of energies, but found out serious influence on descriptions in the “rapid” area of energies of neutrons and on some effects of reactivity. The got results testify to the necessity of subsequent leadthrough of researches for this direction.
Deshko V.I., Sukhodub I.O.
Heat and Mass Transfer Characteristics of Air-to-Air Membrane Recuperator During Heating Season
P. 19–26.
Fig. 8. Refs.: 18 titles.
This paper considers issues of heat and mass transfer simulation in cross flow membrane plate heat exchanger in ventilation systems with condensation and frost formation during heating season. Simulation results are presented in the form of distribution of heat and mass transfer coefficients and heat-transfer agents temperature on the heat exchange surface. We present the dependences of critical conditions of frost formation and sensible efficiency adjustment factor on indoor air relative humidity and outside air temperature. We examine the influence of heat exchanger position on condensation and frost formation processes and difference between condensation zones for sensible and total heat exchangers. Also, we discuss frost control and defrost strategies for heat recovery units in ventilation systems.
Kurilo I.A., Grudska V.P.
Comparative Analysis of the Rectified Voltage Control System with Booster Transformers
P. 27–33.
Fig. 8. Refs.: 8 titles.
The aim of the paper is to make the comparative analysis of the most promising rectified voltage control system layout modifications with booster transformers. We compare energy indices of various control systems and study the influence of zero sequence currents and voltages. We conclude that it is practically expedient to use the control system with the booster transformer whose secondary winding is connected to line wires of the main transformer delta-connected primary winding.
Pukhovyi I.I., Novakivsky E.V.
Coefficients of Southward Orientation of Solar Collectors Depending on their Angles of Slope and Azimuth for Conditions in Ukraine
P. 34–39.
Fig. 9. Tabl. 1. Refs.: 9 titles.
Based on the statistical data on the climate in Ukraine collected from both local and foreign sources, we determine coefficients of southward orientation of solar collectors. They are used at the dependence that considers the stream of solar radiation in clear sky, overcast expressed through power factors and coefficient of efficiency of flat solar collectors or passive systems of solar heating. In addition, we define that in summer more energy can be generated at the southern orientation and slope angles of about 30 degrees. More energy can be generated at the eastern (and western) and south-eastern (south-western) orientations at slope angles to horizon of about 90 and 60 degrees. Orientation coefficients for these slope angles can reach 1,25 in summer. Slope angles of solar collectors are not significant in winter because of cloudy sky, azimuth has a greater impact in winter.
Bidiuk P.I., Demkivskyj Ye.O., Bidiuk O.P.
Data Analysis with Bayesian Models
P. 40–54.
Fig. 1. Tabl. 1. Refs.: 23 titles.
In this paper, we propose to review some Bayesian data analysis models, namely the models with one and several parameters. Using statistical data and expert estimates, we develop the methodology for probabilistic models construction in the form of Bayesian networks. The methodology enables us to construct high adequacy probabilistic models for solving classification and forecasting problems. Furthermore, we propose an integrated dynamic network model by combining probabilistic and regression approaches. This model stands out against the known ones for its ability to estimate multistep forecasts. The forecast estimates computed by applying the dynamic model are compared with the results obtained by employing logistic and multiple regressions. The best results were obtained in this case with the combined dynamic net model.
Ivchenko V.A.
Using Forecasting Methodology for Evaluating Development Scenarios of the AR Crimea Argo-Industrial Sector
P. 55–63.
Fig. 3. Tabl. 3. Refs.: 11 titles.
In this paper we study and formalize the processes of the strategic planning. We define the algorithm to structure and evaluate the development scenarios of the object under research as a part of the strategic planning. In addition, we propose the methodology for choosing actors' policies to achieve the desired future state of the researched system. This methodology takes into account the factors of benefits, costs, opportunities, and risks. The methodology is based on the method of the hierarchy analysis, and utilizes the iterative application of the direct and reverse processes defined in this method. Moreover, we propose the solution to the problem of calculating actors' weights indirectly by the influence of the actors on the considered factors, namely the increase of benefits and oppotunities, and decrease of costs and risks. Finally, we reveal that an integration with other approaches to the management of the economic systems is required for applying our prediction evaluation methodology.
Kapustyan O.A., Yasinsky V.V.
Approximate Regulator for Evolutionary Inclusions subdifferential type
P. 64–68.
Refs.: 10 titles.
The article considers the problem of optimal stabilization for an evolution inclusion of subdifferential type with non-Lipschitz multi-valued interaction function of ε ·F (y), where ε>0 – small parameter. Provided that ε=0 problem allows an optimal regulator u[y], we prove that the formula u[y] provides an approximate stabilization of the initial problem for small ε>0. The obtained results permit us to expand a range of methods for solution of infinite-dimensional evolution problems with discontinuous and multi-valued coefficients and to study the issues of forecasting and control of complex objects relying on systematic approach.
Kasitskyi O.V.
Coordinate Descent Method with Average Weighted Direction Heuristic
P. 69–75.
Fig. 4. Tabl. 6. Refs.: 8 titles.
In this paper, we propose the heuristic for the coordinate descent method. It dramatically enhances the method convergence on “bad” functions for it. Also, we describe the theoretical foundation of the heuristic effectiveness. Furthermore, we propose the effective C++ implementation of the coordinate descent method with average weighted heuristic. Through experiments conducted, we assess the quality of the method under study as compared to gradient descent methods and Rosenbrock method. We show the strengths and weaknesses of this method. Finally, we draw the conclusions on appropriateness of using the method under various conditions.
Molodetska К.V.
Simulation of Thermal Field Rods Based on Differential Spectra Algebraic Properties
P. 76–80.
Fig. 1. Refs.: 10 titles.
The article exemplifies modeling of the thermal field of the rod diameter d by applying the method based on algebraic properties of differential spectra. This enabled to reduce the value of modeling errors and to improve symbolic mathematical descriptions of physical fields. To this end, forward and reverse differential spectra of physical fields of the rod are constructed. Incorrect problems of modeling occurring when coupling discrete direct and inverse spectra is resolved by regularization through incorporating initial and boundary conditions in the balance of differential spectra in a form that allows enhancing the system of equations for uncovering the unknown variables. Simulation results obtained are compared with exact solution of the problem. Hence we determine that they are consistent.
Sokurenko V.M., Nedilyuk V.S.
Numerical evaluation of probabilistic methods for non-continuous global optimization
P. 81–88.
Fig. 4. Tabl. 3. Refs.: 16 titles.
Currently global optimization becomes a widely used technique for solving complex problems in physics, engineering, biology, economy and other fields of human activity. By using the developed computer program, we examine functionality and efficiency of modern global optimization methods such as Improving Hit-and-Run, Simulated Annealing, Genetic Algorithm, Modified Differential Evolution and Electromagnetism-Like-Mechanism. Furthermore, we conduct comparative statistic investigations of these methods under identical stopping conditions over a set of 50 test functions having different complexity and dimension up to 20. Crucially, we reveal that the modified method of differential evolution developed by Ali, Pant and Abraham in 2009 is the most powerful and effective technique. In general, it requires minimum computation efforts to find a global optimum and has the maximum percent of correct solutions as compared to other considered methods.
Bobina M.M., Solovar O.M., Khyzhnyak V.G., Zabolotnyi I.V.
Zirconium Nitring in a Closed Reaction Space
P. 89–93.
Fig. 5. Tabl. 3. Refs.: 6 titles.
Currently there are methods for zirconium nitriding at high temperatures (1300-2000 °C) and long-term exposure (up to 24 hours). This paper aims at developing a novel method of zirconium nitriding at lower temperature and exposure time, while maintaining such satisfactory mechanical properties as coating and matrix. Nitriding was conducted at 900 °C for about 2 hours in an atmosphere of technically pure nitrogen. Samples were placed in the reaction chamber, which could provide the necessary degree of tightness and vacuum. An amount of titanium hydride TiN2 changed from 0,01 to 0,035 kg/m2 in the reaction chamber. Coating was formed on the samples surface. It consists of zirconium oxide ZrO2 on the surface and zirconium nitride under it and a solid solution of nitrogen in a-Zr. Depending on the amount of titanium hydride in the reaction chamber, these layers had different thickness, nitrogen content and microhardness. The obtained results allow developing methods to surface hardening by applying nitrogen and oxygen zirconium alloys used in nuclear power, chemical and medical industries.
Byakova A.V., Yurkova A.I., Gritsenko M.G.
The Effect of Plastic Deformation on the Structure of Powder Quasicrystalline Al–Fe–Cr Alloy
P. 94–98.
Fig. 4. Tabl. 1. Refs.: 12 titles.
The present paper is aimed at studying the effect of compaction by extrusion on the structural features of powder quasicrystalline Al–Fe–Cr alloy. Specifically, we use the powder alluminium alloy Al94Fe3Cr3 with fine-dispersed quasicrystalline particles reinforced by extrusion. We obtain the alloy by applying the water-atomization technique. Using X-ray diffraction analysis, scanning and transmission electron microscopy, we determine that consolidation of powder alloy Al94Fe3Cr3 results in loosing quasicrystalline phase content in a-Al matrix as compared with the initial alloy in the form of powder, which can totally decrease the alloy reinforcement. In addition, the alloy consolidation was conducted by single-axis deformation by extrusion at elevated temperatures (653 K) and high pressure (in the lengthwise and cross directions, notably Pl = 1,42 hPa and Pt = 3,30 hPa).
Gavrilenko O.G., Polyarus E.N., Zhideleva A.V., Minitsky A.V.
The Influence of Magnetic Treatment on Strength Properties of WC–Co and Fe–Al Detonation Coatings
P. 99–103.
Fig. 4. Refs.: 13 titles.
The paper investigates the influence of magnetic treatment on the destruction mechanism of detonation coatings of WC–Co and Fe–Al systems on the steel substrate at bend test. We establish that magnetic treatment enhances mechanical properties of the system “coating–substrate”. The plastic deformation of the system raises from 0,15 to 0, 35 % in the cracking moment. Tensions developed at the destruction moment increases from 700 to 1300 MРa for VK-15 hard-alloy, while for Fe3Al alloy deformation increases from 0,06 to 0,2 % and tensions raises from 214 to 582. The enhancement of properties is caused by improving of the adhesion quality on the “coating-substrate” boundary as a result of elements redistribution at magnetic treatment.
Kuznetsov Yu.N., Dmytriev D.O., Fyranskyy V.B., Stepanenko O.O.
Implementing the Concept of Framework Arrangements of Machine-Tools with Mechanisms of Parallel Structure
P. 104–111.
Fig. 2. Tabl. 1 Refs.: 8 titles.
This paper presents study samples of operating machines with the mechanisms of parallel structures built on the principles of the concept of machine frame layouts. We bring into light our basic ideas of implementing technical solutions according to the requirements of new metal-working equipment in light of modern trends in machine tools, such as multivariate, frame structure of the carrier system, hybridity, symmetrical layout, modular structure of the layout, and visual computer modeling of create layouts creation. Finally, we illustrate examples of forming a set of frame configurations depending on functional features.
Stepanchuk A.N., Demidenko O.A., Demidenko A.V., Shapoval K.O.
Structural Compaction of Iron-Based Powder Materials with Self-Fluxing Alloys
P. 112–116.
Fig. 7. Refs.: 9 titles.
We study the influence of compacting pressure, sintering temperature and composition of iron-based composite materials doped by self-fluxing alloys in the quantity of 10–30 % vol. on the structure, density and hardness. We employ the optical microscope МIM-8M and scanning electron microscope REM-106 to study the structure of materials. Specifically, the hardness testing machine TK-2M is used to conduct hardness testing. We uncover that pressing and sintering conditions, as well as the composition impact density and hardness of materials. Impregnating allows reaching maximum value of materials density during sintering. Finally, we reveal that it is possible to obtain materials with specified structure and properties, as well as certain performance by changing the composition of basic materials and conditions for obtaining products.
Ahmed Malik Lazim Al-Mzirawi, Balinsky E.G, Kolobrodov V.G.
Matching the Resolution of the Lens and Matrix of Medical Thermal Camera
P. 117–120.
Fig. 3. Refs.: 6 titles.
The paper considers the interrelation between radius of the confusion lens circle and the period matrix of modulation transfer function (MPF) with the concurrence lens and the detector. We propose two criteria of the alignment lens and the detector. The first criterion is the equality of the lens and matrix on the level M0 while the second criterion is the equality of the MPF lens detector at the Nyquist frequency. Finally, we uncover the reduced dependence of the normalized radius of the circle ro/VD of confusion on the value of the contrast of the lens alignment M0.
Bantysh A.K., Ostrouh A.P., Ivanova V.V., Taranenko V.B.
Modeling of Discrete Non-Diffracting Beams
P. 121–125.
Fig. 5. Refs.: 4 titles.
In this paper, we propose the technique for computing the scheme of holographic recording on the photopolymer of photonic structures, which create various discrete non-diffracting beams. We study how a number of laser beams, scheme geometry and relative phase shifts between laser beams impact the resultant transverse intensity and phase distribution in the interference structure. Moreover, we numerically model such structures as striped, triangular, square and hexagonal structures, specifically kagome and honeycomb pattern. By applying specific analysis of the beam phase shifts, we simulate vortex structures. These structures are characterized by point and line phase dislocations. We demonstrate experimental results of structures recording and show that adding the central laser beam to the recording scheme makes it possible to obtain a number of 3D structures.
Tkachenko O.A., Chyzh I.G.
Temperature Defocusing of the Image in Optical Systems
P. 126–131.
Fig. 3. Refs.: 7 titles.
We obtain the working formulae. Applying the analytical method, they allow analyzing the temperature effect of optical and mechanical elements of optical system on value of the image temperature defocusing, formed by optical system. Abbe invariant is used to determine the segment, which indicates the position of the image plane relative to the last optical surface of the optical system and is dependent on the temperature magnitude. The formulae permit calculating the value of temperature movement of the image plane according to data of structural parameters of optical system, data of constructions of mechanical details, as well as the data of temperature coefficients of optical system and materials of mechanical details. The account of the local temperature distribution of optical and mechanical components of the optical block device is possible. Furthermore, the method also allows us solving the synthesis problem of optical bock, in which the position of the image plane must be constant with temperature fluctuations in a given interval.
Barbash V.A., Trembus I.V.
Rationale Method of Holocellulose Contents Determination in Non-Wood Plant Materials
P. 132–136.
Fig. 3. Tabl. 1. Refs.: 8 titles.
Method of determination of holocellulose contents in non-wood plant raw materials with taking into account the peculiarities of their anatomical structure and chemical composition was proposed. It was shown that the sustainable level of concentration peracetic acid and hydrogen peroxide determined after seven days of saturation of the solution. The dependences of the holocellulose contents on the duration of treatment different representatives of annual plants were established. It was recommended to process non-wood holocellulose contents plant material by peracetic acid solution for 30 minutes. Holocellulose contents in non-wood plant materials, which were determined by the proposed method with literature data for different plant materials, were compared. Application of the proposed method will unify the determination of holocellulose contents and more accurately determine its contents in various representatives of non-wood plant materials.
Koval I.Z., Starchevskyy V.L.
Intensification Effect of Gas Bubbling in the Processes of Ultrasonic Water Disinfection
P. 137–140.
Fig. 2. Tabl. 2. Refs.: 10 titles.
The paper investigates the influence of various gases on the microorganisms destruction under the ultrasonic water treatment. Under simultaneous action of gas and ultrasound the effective destruction of Bacillus bacteria was achieved for the less process duration as compared with using each agent separately. Water disinfection efficiency at the gas bubbling effect in ultrasound field is about 1,0–1,6 % higher than ultrasound action alone and above 50 % higher than gases effect alone, depending on the gas bubbling nature. The obtained intensification of water disinfection under the simultaneous action of gas and ultrasound shows the importance and practical significance of this method for processing of infected water medium. Moreover, we calculate the values of effective rate constants of microbial cells inactivation and establish dependences of bacteria destruction degrees of time and process conditions. Also, we demonstrate that water purification process from microorganisms is described by the first-order kinetic equation.
Kushmyruk A.I., Kosogin O.V., Linyucheva O.V., Miroshnichenko Yu.S.
Electrochemical Gas Sensor for Determining Hydrogen Sulfide in Air and Technological Environments
P. 141–148.
Fig. 5. Tabl. 1. Refs.: 20 titles.
In this paper, we determine the range of potentials, which shows electrochemical stability and corrosion resistance of titanium and catalytically active electrodes based on it in 5 m of HClO4 solution. We reveal that the current-free potentials of these electrodes comply with compromise potentials conjugate reduction reaction of adsorbed oxygen and oxidation of hydrogen sulfide in the presence of hydrogen sulfide. Based on studies of properties of the semiconductor oxide electrocatalysts of transition metals, gas-diffusion electrodes are developed. It results in the selective anodic oxidation of hydrogen sulfide and allows creating the amperometric sensor for monitoring hydrogen sulfide in air and technological environments on their basis. This sensor surpasses basic technology characteristics of existing analogues of leading international manufacturers. The hydrogen sulfide sensor will contribute to enhancing safety and security in corrosion production that will intensify the development of oil and gas fields, improve the operation of communal services, as well as facilitate rapid analysis of forensic examinations.
Tureluc M.P., Gorobetz S.V., Makedonska A.O., Gorbic P.P.
Biofunctionalization of Nanocomposites Based on Magnetite Modified with Mezo-2,3-Dymercaptosuccin Acid
P. 149–154.
Fig. 6. Tabl. 1. Refs.: 16 titles.
In this paper, we synthesize magnetite-based nanocomposites modified by meso-2,3-dymercaptosuccin acid with biologically active immobilized components (normal human immunoglobulin (Ig) and 2-mercaptonycotin acid (2-MNC). Also, we investigate physical-and-chemical properties of magnetic suspensions based on them. We develop the method of chemical surface modification of single-domain magnetite with thiol groups. The obtained nanocomposite is biofunctionalized by normal human immoglobulin by using sulfo-SMCC heterofunctionalized reagent. We immobilize model biologically active compound 2-MNCs on the surface of magnetically sensitive nanocomposite by the reaction of thiols disulfide exchange using dipiridyl-disulfide. By employing XRT methods and Fourier infrared spectroscopy, we prove the presence of disulfide bridges and SH-groups on the modified surface, and determine the quantitative content of thiol groups.
Fedenko U.M., Dontsova T.A., Astrelin I.M.
Turbidimetry Method of Evaluating the Nanoparticles Sizes in “White Zoles” ZrO2
P. 155–158.
Fig. 4. Tabl. 1. Refs.: 8 titles.
We determine the possibility of employing turbidimetric method for the express evaluation of particles sizes in “white sols” of zirconium oxide (IV) synthesized by hydrothermal method. We define the phase content in zirconium oxide (IV) synthesized by this method, which mainly comprises the tetragonal modification. We find the particles sizes of zirconium oxide (IV) obtained employing the turbidimetric method, as well as by using the ZetaSizer device. Hence the particles sizes are 62 and 65 nm. The obtained data shows that using turbidimetry as an express-method for calculating ZrO2 particles sizes synthesized by the hydrothermal method.