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Shmychkova O.,Ukrainian State University of Chemical Technology | Luk'yanenko T.,Ukrainian State University of Chemical Technology | Velichenko A.,Ukrainian State University of Chemical Technology | Meda L.,Instituto Guido Donegani Energie Non Convenzionali | Amadelli R.,CNR Institute for Organic Syntheses and Photoreactivity
Electrochimica Acta | Year: 2013

The influence of bismuth ions on kinetics of lead dioxide electrodeposition from methanesulfonate elec-trolytes and physico-chemical properties of obtained coatings were studied. Experimental results areconsistent with a mechanism previously proposed in the literature for lead dioxide electrodeposition.The presence of bismuth ions in the electrodeposition solution causes a decrease of rate constants oflead dioxide formation due to co-adsorption phenomena. Deposits from solutions containing bismuthions appear shiny dark grey, and show good adhesion to metal support. SEM images reveal a compactstructure with spindle-shaped submicron and nanosized crystals and X-ray diffractograms demonstratedthat incorporation of bismuth diminishes the size of crystal particles. Oxygen evolution was investigatedto test electrocatalytic activity. It is shown, that oxygen overpotential on modified electrodes is signifi-cantly higher than on non-modified PbO2-electrode, which depends on bismuth content in deposit andsegregation of bismuth that induces surface heterogeneity due to sites with different electroactivity forwater oxidation. © 2013 Elsevier Ltd.


Shmychkova O.,Ukrainian State University of Chemical Technology | Luk'Yanenko T.,Ukrainian State University of Chemical Technology | Amadelli R.,CNR Institute for Organic Syntheses and Photoreactivity | Velichenko A.,Ukrainian State University of Chemical Technology
Journal of Electroanalytical Chemistry | Year: 2013

An investigation is reported on lead dioxide electrodeposition from methanesulfonate electrolytes, that additionally containing Ce3+ ions. It is shown, that ion additive influences on kinetics of PbO2 formation without changing of process mechanism. During the deposition are formed lead dioxide electrodes micromodified by cerium that have different physico-chemical properties vs. traditional PbO2-anodes. Electrocatalytical reactivity of electrodes involved in respect to oxygen evolution was investigated. © 2013 Elsevier B.V. All rights reserved.


Amadelli R.,CNR Institute for Organic Syntheses and Photoreactivity | Samiolo L.,CNR Institute for Organic Syntheses and Photoreactivity | Battisti A.D.,University of Ferrara | Velichenko A.B.,Ukrainian State University of Chemical Technology
Journal of the Electrochemical Society | Year: 2011

The oxidative degradation of phenolic compounds (4-chlorophenol and 4-nitrophenol) was studied using different electrochemical systems involving ozone formation at PbO2 anodes: (i) direct electrolysis at constant current; (ii) ex-situ use of O3 and (iii) combined use of anodically generated stream of O3/O2 fed into the cathode where H2O2 is electrogenerated by O2 reduction. We show that the latter advanced oxidation method gives the best results: it is a Fenton-type degradation of the target pollutants taking place in the cathodic compartment by reason of the highly oxidizing environment brought about by radicals that are formed mainly in the reactions of O3 with OH - and HO2 -. © 2011 The Electrochemical Society.


Kasian O.,Ukrainian State University of Chemical Technology | Luk'yanenko T.,Ukrainian State University of Chemical Technology | Velichenko A.,Ukrainian State University of Chemical Technology
Chemistry and Chemical Technology | Year: 2012

The kinetics of complexing agents anodic decomposition in electrolytes based on Cr(III) salts was investigated. In Cr(III) electrolytes urea was shown to be fixed in complexes with Cr 3+-ions. It was found that the main way of free carbamide degradation was hydrolysis characterized by a high rate (k = 4.5·10 -3 min -1). Decrease in formic acid concentration during electrolysis at composite TiO x/PtO y-anodes was insignificant. © Kasian O., Luk'yanenko T., Velichenko A., 2012.


Anisimov V.,Ukrainian State University of Chemical Technology
Chemistry and Chemical Technology | Year: 2012

The interrelation between structures and strength, deformation, rheological, and tribotechnical characteristics of thermoplastic polyurethanes based on oligoether blends has been studied. A notable change of properties over the whole concentration range was observed. The best compositions have been found. © Anisimov V., 2012.


Protsenko V.S.,Ukrainian State University of Chemical Technology | Gordiienko V.O.,Ukrainian State University of Chemical Technology | Danilov F.I.,Ukrainian State University of Chemical Technology
Electrochemistry Communications | Year: 2012

Kinetics and mechanism of chromium-carbon alloy deposition process were investigated using trivalent chromium electroplating bath containing formic acid and carbamide (urea). The rate of carbon co-deposition process is determined by the rate of chromium electroplating reaction (electrochemical process of Cr-deposition imposes its own kinetics regularities on carbon co-deposition). It was supposed that a part of active chromium ad-atoms generated as a result of Cr(II) ions discharge may interact with adsorbed organic bath constituents by "chemical" mechanism. © 2012 Elsevier B.V.


Apostolova R.,Ukrainian State University of Chemical Technology | Peskov R.,Ukrainian State University of Chemical Technology | Shembel E.,Ukrainian State University of Chemical Technology
Journal of Solid State Electrochemistry | Year: 2014

We reported previously the superiority of electrochemical characteristics of the mechanical mixtures of micrometer LiMn2O4 spinel with multiwall carbon nanotubes (MCNT) over those of spinel compositions with natural graphite in the prototypes of the Li-ion batteries. In the presented work, we extended the investigation of the kinetic and interfacial characteristics of the spinel in the redox reaction with the Li ion. Slow-rate scan cyclic voltammetry and impedance spectroscopy were used. Carbon electroconductive fillers, their nature, and particle sizes play the key role in the efficiency of the electrochemical transformation of spinel in Li-ion batteries. Electrodes based on the composition of the spinel and MCNT show a good cycling stability and efficiency at the discharge rate of 2C. Chemical diffusion coefficients of Li ion, which were determined in spinel composite with MCNT and graphite near potentials of peak activity in deintercalation/ intercalation processes, change within one order of 10-12 cm 2 s-1. The value of this chemical diffusion coefficient for the composition of the spinel with MCNT and with graphite change within one order of 10-12 cm2 s-1. The data of the impedance spectroscopy shows that the resistance of surface films on the spinel (R s) is low and does not considerably differ from R s in composites of the spinel with MCNT and graphite. The investigation shows that the resistance of charge transport (R ct) through the boundary of surface film/spinel composite is dependent on the conductive filler. Value of R ct in spinel electrode decreases by the factor of thousand in the presence of carbon filler. Exchange current of spinel electrode increases from the order of 10-7 to 10-4 A cm-2 under the influence of MCNT. At the potentials of maximum activity in deintercalation processes, exchange current of spinel composite electrode with MCNT is 2.2-3.0 times more than one of the composite with graphite. Determining role of the resistance of charge transport in electrode processes of spinel is established. The value of R ct is dependent on the resistance in contacts between spinel particles and also between particles and current collectors. Contact resistance decreases under the influence of MCNT with more efficiency than under the influence of graphite EUZ-M because of small the size of its particles with high surface area of the MCNT. © 2013 Springer-Verlag Berlin Heidelberg.


Vinogradov B.V.,Ukrainian State University of Chemical Technology
Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu | Year: 2016

Purpose: To estimate the effectiveness of the coupling with rubber-cord shells for evenly distributed load between the transmission lines in the twin-motor drives of tumbling mills. Methodology: We gave the dynamic and static elastic characteristics of clutches and drive containing the coupling with rubber-cord shells. The performance of couplings containing rubber-cord shell was analyzed based on the mathematical models describing the load transmission lines of each engine depending on the displacement angle of the motor and hydraulic couplings parameters. Findings: The schemes and characteristics of clutches containing rubber-cord shell are presented. It was proved that these couplings, in case of use of the rubber-cord shells available at the market allow transmitting the torque of up to 8,000 kN · m, which satisfies the twin-engine drives with a total capacity up to 10,000 kW. We considered the drives containing the coupling with rubber-cord shells filled with a liquid and connected with hydropneumatic accumulator for the cases when the hydraulic system of rubber-cord shells is independent and connected by the common pipeline. The technique of quantitative evaluation of the uneven distribution of load between the engines was developed. Originality: The regularities of distribution of static loads in synchronous twin-drum drive mills containing elastic couplings with rubber-cord shells Practical value: It was proved that the use of flexible couplings with rubber-cord shells without hydraulic connection between the couplings results in a more even load distribution due to the increased compliance of the mechanical system.


Protsenko V.S.,Ukrainian State University of Chemical Technology | Danilov F.I.,Ukrainian State University of Chemical Technology
Journal of Electroanalytical Chemistry | Year: 2011

Equations are derived and analyzed that interrelate the quantities of the ideal activation energy W (determined at a constant Galvani potential value), the real activation energy A (measured at a constant overpotential value) and the so-called formal activation energy Ω (measured at a constant electrode potential vs. an arbitrarily chosen reference electrode). The mathematical forms of dependence of apparent formal activation energy on electrode potential are established. It is shown that using formal activation energy (measured at a constant electrode potential) is applicable for kinetics analysis of various electrode processes. The expressions obtained in this study may be used when processing temperature dependences of highly irreversible electrochemical reactions. © 2010 Elsevier B.V. All rights reserved.


Olevskyi V.,Ukrainian State University of Chemical Technology
AIP Conference Proceedings | Year: 2014

We propose the method of modeling, which provides a meromorphic continuation of the asymptotic polynomial solution of differential equations based on 2D Padé approximants in nonlinear shell theory. We represent calculations of displacements, stability and vibration of inhomogeneous loaded shells with developable surface by means of this method. Accuracy of theoretic results is confirmed by means of holographic experiments with specimens made from stainless steel. © 2014 AIP Publishing LLC.

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