Kuzmichev A.I.
Simulation of Ionization and Emission Processes in the High-Voltage Electron-ion System with Cold Cathode and Pulse Ion Generator
P. 7–12.
Fig. 4. Refs.: 4 titles.
This paper develops the mathematical model of high-voltage low-pressure electron-ion system with a cold cathode and a pulse plasma ion generator disposed behind an anode. The model is based on kinetic equations describing time dynamics of ionization processes in the plane electrode gap with participation of electrons, ions and neutral species after ion charge exchange, as well as electrode emission processes, including reflection of atoms from cathode and electrons from anode. Numerical calculations allowed revealing and studying regimes of non-self-maintained and self-maintained discharges initiated by pulse injection of ions from the anode at gas pressures, accordingly, below and above some critical value. Continuously operating ion generator is needed to maintain the non-self-maintained discharge. The ion generator may be switched off after initiating the self-maintained discharge but duration of transient process of establishing this discharge can be shorted by increase of injected ion current density and injection pulse duration. Velocity and energy distributions of flows of high-energy particles going to the electrodes and time dynamics of variation of these flows are determined in different sections of the electrode gap. The obtained data is used for developing pulse electron and ion sources as well as of devices for thermo-ion deposition of materials in particular for manufacturing electromagnetic metamaterials.
Keywords: ionization, secondary electron emission, cold cathode, high-voltage low-pressure system, self-maintained discharge, non-self-maintained discharge, pulse plasma ion generator.
Prodeus A.M.
Speech Corpora as Facilities of Creation and Storage of Exemplary Speech Signals
P. 13–19.
Fig. 2. Refs.: 22 titles.
Speech corpora are an important constituent of modern investigators’ toolkit in such areas as speech correction, designing and testing elements of telecommunication systems and systems of automatic speech recognition. In this paper, we search for elements of construction technology of the sound part of noisy Ukrainian speech corpora. To this end, we consider characteristics of the most wiely used modern noisy speech corpora which allow formulating principles of such corpora design. The regularity of formulated principles is shown by an example of known modern program toolkit FaNT which permits constructing quickly speech corpora with required properties. The guidelines on constructing similar program toolkit in Matlab environment are developed. Such toolkit will allow not only to work out by joint efforts the best version of a Ukrainian noisy speech corpus, but to compare algorithms of noise reduction and algorithms of automatic speech recognition elaborated by various scientists with one another in the future.
Keywords: speech corpus, noisy speech, signal distortions, program toolkit.
Strelkovskaya I.V., Solovskaya I.N., Gutsal Ju.V.
Defining Parameters of Quality Mobile Network Technology LTE/MVNO with Tensor Analysis
P. 20–26.
Fig. 2. Refs.: 8 titles.
The paper under scrutiny proposes the sequence of actions for characterizing the quality parameters of the mobile network LTE/MVNO for convenient configuration of network connections of objects. To determine the quality parameters of the network LTE/MVNO tensor decomposition of the network architecture we employ the method for obtaining the optimal configuration of the network connections of objects for preset values of packet delay using the criterion of the maximum capacity. To consider more complex network topology and architecture using tensor decomposition we propose to divide it into subnets for further research and obtaining findings for each subnet in isolation and the network as a whole. We determine the parameters of the quality of the network LTE/MVNO such as bandwidth, packet queue length in the path, the contours of the network nodes for each subnet and the network as a whole. The resulting tensor method can be used for a variety of networking tasks taking into account the complexity of the architecture and topology with specificity of functioning of the protocols used.
Keywords: tensor methods, decomposition network, the quality of the network, bandwidth, packet delay, packet queue length.
Kovrygo Yu.M., Bahan T.H.
Method of Setting H¥-Pidregulators for Objects with Delay
P. 27–33.
Fig. 6. Refs.: 5 titles.
Given the widespread use of PID controller and the presence of uncertainties for thermal facilities, the synthesis method should be developed. It can be instrumental in obtaining sufficient robustness and providing practically important quality indicators of the closed-loop system within the set limits of uncertainty besides unconditional stabilization facility with delay. Using the optimality criterion as H¥ norm closed system, we obtain PID controller settings for objects with delay. We show that by changing the parameter settings l of the controller we can achieve the desired compromise between the quality metrics and the system robustness. Optimality criterion as H¥ norm of the closed-loop system enables easy and quick setting of the PID controller for objects of the 1st and 2nd order with delay. These settings will definitely depend on the object parameters and the value of l. By changing this ratio we can guarantee that a specified direct indicator of quality which is rather convenient in practice can be elaborated. Alternatively we can achieve the desired combination of several indexes of quality for the worst system case, thus ensure its robustness.
Keywords: PID controller, H¥-control, nominal quality, robustness.
Pukhovyі I.I., Nikolaenko Yu.Ye., Postolenko A.M.
Using Cold from Snow, Ice and Ground for Cooling Small Data Centers in Ukraine
P. 34–38.
Fig. 2. Refs.: 12 titles.
In this paper, we consider using renewable sources of cold (snow, ice and ground) for cooling server premises. We determine the required volumes of snow and ice for an average capacity of 10 kW during 7 months in southern regions of Ukraine and 4 months in the northern regions of Ukraine. The volume of snow and ice accumulators intended for 7 months of operation taking into account accumulation efficiency coefficient is about 2000 and 1000 tones. The ice and snow accumulators require the area from 50 to 300 square meters. Due to electricity saving and selling СО2 emission quotes, snow accumulators can pay off within 10 years and ice accumulators can pay off when the ice is produced from water at the consumption place only at the water price less than 1 UAH (0,125 USD) per m3, which can be obtained through using surface waters and relatively pure cooled sewage water. When the heat of phase transition is used for air heating for ventilation or heat pumps, the ice accumulation system pays off even when the running water is used. The installation of horizontal ground heat exchangers made of polymer pipes with a diameter of 120 to 140 mm for cooling of atmospheric air swill pay off approximately within 3 years.
Keywords: data centers, cooling, snow, ice, ground, accumulation, capital expenses, operating expenses, payback period, sale of СО2 emission quotes.
Yandulskii O.S., Timokhin O.V., Timokhina A.O.
Increasing the Efficiency of Frequency Load Shedding of Power System
P. 39–43.
Fig. 7. Tabl. 2. Refs.: 9 titles.
The paper considers the frequency load shedding of an electric power system. The objective of this paper is to enhance the structure and algorithms of frequency load shedding-1 (AUFLS-1) using cutting-edge technologies, namely Wide Area Measurement System. We model the operation of the system of complex power supply when various emergencies in the Power Factory software occur. We aim at revealing the fact of the voltage corner reaction on the emergency occurrence and elaborating the algorithm of detecting the emergency by speed of voltage corner change. The result and novelty of this research is that we propose how to upgrade the system AUFLS-1 by introducing the additional starting block reacting to the speed of the voltage corner change which increases the speed of AUFLS-1 system operation. As a result the system AUFLS-1 starts up not only by achieving “frequency” set point but also by analyzing the speed of voltage corner change.
Keywords: emergency control automatics, Wide Area Measurement System (WAMS), under frequency load shedding.
Zahirska I.O., Bidyuk P.I.
A Scenario Approach to Modeling of the Pacific Trash Vortex
P. 44–50.
Fig. 4. Tabl. 6. Refs.: 21 назва.
The study performed aimed at constructing and comparing scenarios of the solid waste treatment policy in different countries and their influence on variations of environmental dynamics changes in the area of ecological catastrophe – Pacific trash vortex. As input data for the scenario constructing and performing corresponding analysis the statistics for the solid waste processing in the USA, European Union and Singapore was used. The models were constructed for forecasting of the waste accumulated and the percentage of their processing. It was established that the process of the waste accumulation is described best with autoregressive model and structural model with trend. The basic trends for further development of the process under study have been discovered. Over the next ten years the implementation of various solid waste treatment scenarios in the world can cause a variety of implications for the Pacific trash vortex and ecological situation in general, as discussed in the article. A comparative analysis of the policy scenarios for the solid waste treatment was carried out. Using as an example this environmental problem a general methodology of scenario building is described. The indicators to define the robustness of these scenarios and the best one of them were found using actual data. The following tools were used for the purpose: scenario modeling, decision tree constructing for probabilistic modeling, autoregression models and models with description of trend.
Keywords: ocean ecology, Pacific trash vortex, statistical data, regression models, scenario analysis, scenario tree, perspectives
Bohushevskij V.S., Yehorov K.V.
Control of Bath Dynamics along Purging as Part of the Control System Converter Melting
P. 51–56.
Fig. 1. Refs.: 9 titles.
The purpose of research is to lay the theoretical foundation and specify the control model of bath dynamics along the blowdown. The research is conducted on converters of 160 tons. Specifically, we study the control dynamics of decarbonization and changes of bath temperature. We use deterministic and statistical methods to process the research results. We obtain the estimates of carbon content and temperature of bath converter depending on the accuracy of priori (intensity purging, distance lance to the level of metal, etc.) and posteriori information (analysis of exhaust gases from the converter, heat flows into the tuyere cooler and converter gases, etc.) as well as the kinetic melting period. We obtain the smallest errors relying on compatible balance and statistical methods. The easiest way to control the bath dynamics is direct measurement of initial parameters of the process, notably temperature, composition of metal and slag and their masses. The mathematical model is tested when the carbon mass fraction is predicted at the converter facility of the V.I. Lenin Metallurgy Plant. Finally, we determine that standard deviation of calculated mass fraction of carbon for medium-and low-carbon steels is 0,045 %.
Keywords: process, control, converter, blowing, gas, tuyere, system, the rate, coefficient, analysis.
Burmak А.P., Sidorenko S.I., Vasylyev М.O., Voloshko S.M.
Cyclic Character of the Microhardness Aluminium Alloy D16 under Ultrasonic Impact Treatment
P. 57–62.
Fig. 4. Refs.: 14 titles.
The article studies possibilities of more effective surface hardening as compared with conventional thermo-mechanical processing. Specifically, we provide the insight into surface hardening of light structural alloys by ultrasonic impact treatment (UIT) in air under quasi-hydrostatic pressure of the sample. By example of the commercial aluminum alloy D16 we demonstrate the unique opportunity to harden the surface (up to ~600 %) using the synergistic effect of low-temperature processes of mechanical nanostructuring as well as mechanical and chemical interaction of aluminum with oxygen under the influence of UIT. We propose the qualitative model for formation of oxide coating several tens of micrometers thick. By employing a set of physical methods we establish basic laws of the phase formation and chemical composition, structure and mechanical properties of the D16 alloy surface layers depending on the amplitude and duration of UIT. We show that the development of dynamic recovery and dynamic recrystallization processes causes the cyclic nature of microhardness changes. Under optimal conditions of UIT the wear resistance of surface layers increased by ~2,5 times, and the compression residual stresses level is 650 MPa.
Keywords: ultrasonic impact treatment, aluminum alloy, nanostructure, aluminum oxide.
Gavrish А.P., Кyrychok P.O., Roik Т.A., Vitsuk Yu.Yu.
Analysis of surfaces’ quality parameters of sliding bearings Made of composite alloys for printing machines at abrasive grinding
P. 63–67.
Tabl. 5. Refs.: 10 titles.
In the article we present the research results of defect layers formation on surfaces of sliding bearings made of new high-alloy composite alloys produced from tool steels wastes and intended for high-speed printing machines. We show that such quality parameters of surfaces like cold-work strengthening, depth of its bedding, and range of cold-work strengthening and distortions of the 2-nd type are formed as a result of interaction between force and temperature fields appearing on the top of abrasive grain at fine abrasive grinding of friction surfaces of sliding bearings. We prove that final quality of surfaces depends on interaction of simultaneously arising processes of strengthening and tempering of working surfaces of sliding bearings at abrasive grinding. Moreover, we define the dependence of range of cold-work strengthening, its depth and distortions of the 2-nd type from composition of abrasive tool, its graininess, bond type of abrasive disc, parameters of grinding: using lubricating and cooling liquid, depth of grinding, rotation speed of the disc and line feed. We make the recommendation on how to choose grinding tools and cutting parameters for industrial purposes which meet the demands to quality of friction surfaces of high-speed bearings for rotary printing machines.
Kyrychok T.Yu.
Algorithm for Solving Multicriteria Problem of Choice of Banknote Deterioration Characteristics Using the Utility Function
P. 68–75.
Fig. 1. Tabl. 4. Refs.: 12 titles.
The utility functions of alternatives based on additive, multiplicative, additive-multiplicative and entropy convolutions of factors as well as metrics of Chebyshev, Euclid, Minkowski and the method of deviation from the sample have been formed taking into account separation of factors for stimulators and destimulators. The algorithm of the determination of alternatives' preferences was developed on base utility function. The developed algorithm is implemented for solving of multicriteria problem of choice the most accurate characteristic of deterioration for banknotes in real circulation. It was found that the most accurate characteristic suitable for a reliable banknote sorting is a mass. All proposed methods of formation of the utility function have a high accuracy of the alternatives' preferences determination within the range of individual criteria and criteria weights typical for printing production. The least standard deviations are demonstrated by utility functions that are based on the Euclidean and Minkowski metrics and the multiplicative and additive – multiplicative convolution of criteria.
Keywords: utility function, convolution, stimulators, destimulator, multicriteria problem, banknote sorting, banknote deterioration.
Kylinich А.A.
Influence of Temperature-Temporal Parameters of Annealing on Structure and Mechanical Properties of Alloy АМг6л with Enhanced Maintenance of Silicon
P. 76–79.
Fig. 1. Tabl. 4. Refs.: 5 titles.
In this paper we study the influence of temperature-temporal parameters of in-process annealing set on structure and mechanical properties of alloy АМг6л with 1 % of silicon admixtures. Melting is conducted in the laboratory resistance stove in graphite crucible. We use the following materials: aluminium А99, ligature Al–Mg, Al–Zr, Al–Be, Al–Ti, Al–Si. The obtained standard samples 10 mm in diameter are annealed at different temperature-temporal parameters. Also, we determine their mechanical properties. We establish that alloy АМг6л can reach the maximum level of mechanical properties 1,0 % Si after annealing at the following mode – 430 °С, 20 h. + 530 °С , 8 h. The replacement of the standard annealing for the new mode for the alloy under study containing 1 % Si allows increasing the values of temporal break resistance by 12 %, and relative lengthening by 41 %. The new mode of annealing is instrumental in changing the phase morphology of Mg2Si from ramified one to a more compact. Also, grinding and spheroidizing of the particles take place. It influences the increase of level of mechanical properties of alloy АМг6л.
Keywords: phase composition, structure, annealing, morphology, mechanical properties.
Legeza V.P., Dychka I.A., Legeza D.V.
Mathematical Simulation of Oscillations of a String with Movable Bearing in a Vertical Plane
P. 80–83.
Fig. 1. Tabl. 1. Refs.: 11 titles.
We consider the natural oscillations of the string whose left end is fixed and the right one has the ability to move in a vertical plane by a defined law. We should address this issue to construct an adequate mathematical model of the electric wire taking into account longitudinal displacement of one of its ends. The right-hand mobile support is a commuting pendant with electric wire in the form of insulator strings. The purpose of research is to show and justify the boundary conditions occurring during vibration of a string considering the movements of its right pillar and solve the corresponding boundary problem. The technique for solving the boundary value problem lies in the state that the solution of the wave equation should be searched in such a form that its time-average standard deviation derived from the boundary condition should be minimal. Emphasized should be the obtained research results: change of fundamental frequency of basic tone of string vibrations caused by its right pillar movement in vertical plane within the range of parameters change of the considered system can be neglected.
Keywords: galloping of wires, oscillations of string, border task, variable border conditions, frequency of basic tone of oscillations, averaging method, isochronous absorber.
Smokovych I.Ia., Loskutova Т.V., Khyzhnyak V.G., Pogrebova I.S.
Heat Resistance and Corrosion Resistance of Complex Chromium+Aluminum Diffusion Coatings on Titanium Alloy VT6
P. 84–88.
Fig. 3. Tabl. 1. Refs.: 11 titles.
In this paper we study the microstructure, phase and chemical composition of complex chromium+aluminum diffusion coatings obtained by simultaneous saturation of titanium alloy VT6 with chromium and aluminum from powder mixtures. We discover that coatings consist of three separate layers of Al3Ti, AlTi, AlTi3 phases. The microhardness of diffusion multilayers in the area of Al3Ti phase is 7,1–9,0 GPa, of the main diffusion layer AlTi – 5,2–8,2 GPa and 11,0 GPa for the AlTi3 phase, that is by 2-4 times higher the microhardness of initial VT6 (3,63 GPa). The heat resistance of the titanium alloy VT6 increases from 450 to 700 °C due to formation of protective oxides films of aluminum and chromium on the surface. Corrosion resistance of VT6 increases by 2,52 times in an aqueous solution of 5 % HOOC(CH2)4COOH acid and by 9,53 times in an aqueous solution of 3 % H2O2. Furthermore, diffusion chromium+aluminum coatings obtained using the proposed method may be suitable for practical use on parts and constructions made of titanium alloy VT6 to improve their performance properties and to extend the operation life under conditions of high temperatures, abrasion and relevant aggressive environments.
Keywords: titanium alloys, VT6, diffusion coatings, chromium, aluminum, microhardness, heat resistance, corrosion resistance.
Denysov M.О.
The Model of Optical Radiation Propagation in Tissue
P. 89–93.
Fig. 3. Refs.: 12 titles.
The paper shows the relevance of developing the model of optical radiation propagation in tissue that will further implementatation of calculation engineering methods of optical radiation intensity distribution in tissues for surgical intervention or therapeutic effect. We propose the so called “three pulse” model of optical radiation propagation in tissue and method based on it. To calculate the coefficients of the model basic expression, we develop the three-equation system. These equations describe the boundary conditions of optical radiation propagation in tissue. By using the Monte-Carlo simulation method and proposed engineering method we compare results of optical propagation in tissue for identical tissue optical parameters. These results correlate with the mean square modelling error (within 15 %) for other analytical models. The proposed calculation engineering method for optical radiation intensity distribution in tissue may be alternative for Monte-Carlo simulation method with considerable calculation simplification and calculating time reduction.
Keywords: model, tissue, radiation, Monte-Carlo, method.
Kolobrodov V.G., Mykytenko V.I., Siryi Ie.A.
Investigation of Kinoform Element Chromatism
P. 94–98.
Fig. 7. Tabl. 1. Refs.: 5 titles.
The paper investigates the chromatic characteristic of the kinoform element in a given spectral range. Based on the well-known chromatism theory we obtain more exact expressions of the chromatic focus shift and the dispersion coefficient. The enhanced chromatism theory determined that the chromatic focus shift and the dispersion coefficient depend not only on a spectral range but also on a Fresnel zone number. Based on the enahnced theory we analyze the kinoform chromatism in the spectral range of 8–12 µm. We demonstrate that the element focuses the light with design wavelength to a single point, other light – to an uniformly illuminated line. We detect that the dispersion coefficient isn’t a constant, it has different value within each kinoform diffractive zones. Furthermore we analyze the geometry size of a monochromatic spot focused in an imaging region by all Fresnel zones. We propose the method for determining the imaging plane optimal location, in which spot size has minimal value.
Kucherenko О.K., Muraviov O.V., Ostapenko D.O.
Temperature Influence on Aberration Properties of Infra-Red Lenses
P. 99–105.
Fig. 4. Tabl. 5. Refs.: 7 titles.
This paper considers temperature influence on image quality of focusing systems operating in an infra-red spectral range for the case of homogeneous temperature distribution. Using the optical design programs it is possible to estimate the influence of temperature on optical descriptions of depicting systems operating under unstable temperature conditions. The article elucidates the results of temperature influence analysis on aberration properties of non-athermalized and athermalized infra-red lenses. The analysis conducted shows that at the temperature change to 40 degrees in the system of typical infra-red lens projected without taking into account temperature influence the system resolvability worsens by several times as a result of thermal misfocusing. At the same time the nature of the field aberrations dependence on the entrance pupil size or corner of optical system eyeshot in the image plane does not change. By using passive optical athermalization methods the dependence of infra-red lenses characteristics on temperature can be eliminated at the stage of focusing system projection.
Keywords: thermoaberrations, infra-red lenses, thermal defocusing.
Stelmakh N.V.
Formation of the Model Structure of Assembly Products in Instrument-Making
P. 106–110.
Fig. 4. Refs.: 7 titles.
The paper deals with the specific nature of assembly processes in instrument-making and considers the current state of development of computer-aided design technology assembly and their suitability for conditions of instrument-making production. In addition, we develop the mathematical model of the assembly product in instrument-making taking into account complexity and specificity of the assembly, adjustment and test work. We propose the method of forming the model describing the structure of the assembly product which represents it as a hierarchical system of interconnected structural elements. The proposed model is integrated in the CAD system. It is informative and suitable for the process of automated assembly design. Relying on the proposed method describing the product structure we develop the software “AsCAM” containing the procedures and database design and technology information. This software can effectively solve the problem of technology preparation of small-scale assembly plant in construction of the circuit assembly of the product and flow diagram of assembly.
Keywords: component design, assembly products, the model describing the structure of products, computer aided design.
Tymchik G.S., Tereshchenko M.F., Rudyk V.U.
The System of Temperature Control in a Magnetotherapy
P. 111–116.
Fig. 6. Tabl. 2. Refs.: 8 titles.
The article is devoted to the issue of the temperature control of a biological object in the magnetotherapy. We develop the mathematical model of the magnetic field influence on a biological object with the control of the temperature variation on the surface epidermis areas. We conduct an experimental research of temperature variation of a biological object with magnetotherapy apparatuses “MIT-11” and “POLUS-4”. The quantitative and qualitative estimation of theoretical and experimental research results of a thermal field shows high convergence of results and efficiency of the developed mathematical model of specific thermal action of a magnetic field on a biological tissue. Based on experimental and theoretical research we elaborate the system of temperature control and pointed precisely acting dosage of magnetic field on biological tissue providing high efficiency of the therapeutic effect of required forms of magnetic fields on biological tissue due to the measuring of temperature gradient during the magnetotherapy procedure.
Keywords: magnetotherapy, magnetotherapy apparatus, magnetic field, temperature method of control.
Barbash V.A.
Microcrystalline Cellulose from Bast Plants
P. 117–122.
Tabl. 4. Refs.: 14 titles.
It was found that the chemical composition of flax fiber is common to cotton fiber, but differs from the stems of hemp and kenaf, softwood and hardwood because of higher content of ash, lesser lignin and pentosans content. Stems of hemp and kenaf compared with wood at approximately the same cellulose content have lesser lignin content, ash content and a much larger number of substances that dissolve in water and NaOH. It is shown that the water preliminary hydrolysis of bast plants compared with acid preliminary hydrolysis leads to less extraction of herbal minerals, hemicelluloses and cellulose fractions of low molecular weight. Increasing liquid to solid ratio in acid preliminary hydrolysis reduces mineral content in fibers and stems of plants, resulting in decreased yield and increased content of residual lignin in pulps. Cellulose was obtained by alkaline-sulfite-alcohol method of bast plants delignification. Different schemes of bleaching organosolvent pulp using various charges of calcium hypochlorite, hydrogen peroxide and hydrochloric acid were investigated. It is shown that stage of hydrolysis organosolvent bleached cellulose by solutions of sulfuric acid and hydrogen peroxide provides microcrystalline cellulose with the required quality indexes.
Keywords: microcrystalline cellulose, flax, hemp, kenaf, preliminary hydrolysis, organosolvent cooking, bleaching, hydrolysis.
Vorobyova V.I., Chygyrynets’ О.E., Chygyrynets’ E.О.
Investigation Inhibition Properties of Volatile Atmospheric Corrosion Inhibitor Based on Natural Material
P. 123–128.
Fig. 4. Tabl. 3. Refs.: 16 titles.
The aim was to study the component composition of the volatile compounds of hops isopropanol extract and evaluation of physical and chemical properties of the new film on the metal surface. The volatiles extract of hope cones are analysed by Gas Chromatography–Mass Spectrometry (GC–MS). Based on the data of the gas chromatography-mass spectrometry we identify the qualitative composition of the volatile compounds of the extract hops “Aromatic”. The main components are terpenoids, ketones, phenolic compounds, phenol and phenol carboxylic acid. Hope cones extract is developed as novel volatile corrosion inhibitors and can be used as solution and impregnated paper (VPI paper). We also study the effect of volatile compounds isopropanol extract of the kinetics of the partial electrode reactions. The experimental results show that the investigated extract, which can effectively retard the anodic dissolution of steel, are anodic inhibitors. We discover that the using volatile fractions of the hops extract as an inhibitor leads to formation of the film shifts of corrosion potential in the positive direction and significantly reduces the corrosion rate. The maximum increase in the hydrophobicity and the shift of the corrosion potential in the positive direction is observed after steel pre-treatment for 2 days in vapors of extract volatile compounds.
Keywords: hop cones, VCI, atmospheric corrosion, component composition, gas chromatography-mass spectrometry.
Vorobyova M.I., Pivovarov A.A.
Dissolution Silver in Plasma Chemically Activated Solutions
P. 129–134.
Fig. 3. Tabl. 1. Refs.: 17 titles.
This study suggests the possibility and efficiency of application solutions treated under the contact non-equilibrium low-temperature plasma for intensification dissolution of silver in cyanide leaching systems. The obtained research results show that plasma activated solutions due to the complex of peroxide and super peroxides compounds, radicals and particles formed in water during processing have higher oxidizing properties compared to synthetic hydrogen peroxide and oxygen commonly used in the hydrometallurgical industry as oxidizing component. We investigate that the influence of main technology parameters on the speed of the process of silver dissolution in activated solutions, as well as synthetic hydrogen peroxide and oxygen. In addition, we show that the silver dissolution in all cases is characterized by transitional type kinetics proved by the calculated values of activation energies. The comparison of values of activation energies show the advantage of using activated solutions before adding synthetically hydrogen peroxide and oxygen.
Keywords: kinetics, dissolution, silver, rotating disk, plasma-chemical activated water.
Gorobets О.Yu., Gorobets Yu.I., Rospotnyuk V.P.
Electromotive Force at Etching Homogeneous Magnetized Steel Cylinder in the Electrolyte
P. 135–141.
Fig. 3. Refs.: 26 titles.
In this paper, we calculate the electric cell voltage of the physical circuit at etching of ferromagnetic electrode in the form of a cylinder in an electrolyte caused by inhomogeneous distribution of concentration of the paramagnetic corrosion products on the surface of a steel cylinder in an inhomogeneous magnetostatic field. The shape of the electrode was chosen because all points of the cylinder surface are equivalent in this model system in the absence of magnetization and effects of the magnetic field can be easily separated from the effects of a different nature. The current density and Lorentz force are calculated in an electrolyte in the vicinity of the magnetized steel cylinder. The Lorentz force causes movement of an electrolyte perpendicular to the direction of the external magnetic field along the cylinder axis. Comparison of calculations with experimental data allows concluding that a certain part of paramagnetic ions in the electrolyte in a magnetic field represents the nanoclusters of paramagnetic ions, which can be for example nanobubbles. The results of the theoretical modeling can be used for creating functional materials by means of magnetoelectrolysis and for modeling of the influence of the biogenic magnetic nanoparticles on transport processes and biochemical reactions in cells of live organisms.
Keywords: Magnetohydrodynamic stirring, magnetoelectrolysis, effective paramagnetic susceptibility, gradient magnetic force, Lorentz force, micro- and nanobubbles.