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Yekaterinburg, Russia

Kuzmin E.A.,Ural State University of Economics
Biosciences Biotechnology Research Asia | Year: 2015

A focus of the paper is a problem of "observability" regarding food security. Known scientific approaches to identification of a similar condition have not provided us with a grounded solution to refer to actual borders of security (or standards of mutual penetration). Their absence makes methodological capacities of modelling essentially disturbed. It is levelling of these contradictions that is an aim of this research. The authors put forward and give a scientific rationale for a hypothesis for fragmentary food security, an essence of which is come down to a research on certain agricultural commodity groups. In a critical review, features of security are specified. A theoretical development of authors' provisions have resulted in formalization of a number of models built in terms of the dependence factor or inherent openness of the food system. These and other features have made it possible to offer a distinctive technique for an analytical interpretation of findings, including an assessment of risk for lost security condition in a food aspect of the issue. Source


Brainina K.Z.,Ural State University of Economics | Galperin L.G.,Ural State Technical University | Galperin A.L.,Ural Federal University
Journal of Solid State Electrochemistry | Year: 2010

A mathematical model is proposed that describes the processes of electrooxidation of metal nanoparticles localized on the surface of an indifferent macroelectrode. In contrast to previously proposed models based on geometric factors (shapes of particles and diffusion zones), the proposed model has introduced thermodynamic considerations which take into account the energy differences between the nanoparticle ensembles from microparticles and macroparticles. A series of voltammograms was obtained as a result of calculations and characteristic relationships between the different parameters were found. An analysis of the findings, on the one hand, predicts the shape and characteristic features of the experimental voltammograms and, on the other hand, provides information regarding energetic properties of the nanoparticles. © 2009 Springer-Verlag. Source


Brainina Kh.Z.,Ural State University of Economics | Galperin L.G.,Ural Federal University | Vikulova E.V.,Ural State University of Economics
Journal of Solid State Electrochemistry | Year: 2012

It is shown that nanoparticles localized on a foreign solid electrode may display two opposite shifts of dissolution potential, namely, a shift toward either more positive or more negative values as compared with the equilibrium potential of M n+/M 0 or the potential of bulk metal electrooxidation. The observed phenomena are interpreted in view of three energy states of substance, which are realized depending on contribution of the surface Gibbs free energy (ΔG°) to the energy of the system. Literature data concerning different metalsubstrate pairs and specially conducted experimental investigations of electrooxidation of gold nanoparticles (radius equal to 10 and 150 nm), which are localized on the surface of glassy carbon, bulk gold, and platinum electrodes are presented and discussed. A shift of maximum current potential of small nanoparticles oxidation toward more positive values is observed in this series. The oxidation potential of large nanoparticles is not affected by the nature of the substrate. In all cases, electrooxidation of gold nanoparticles occurs at the more negative potentials than those of the bulk gold electrooxidation. It is shown that depending on the nature of the substrate and nanoparticle size, the dominating effect is either interaction of nanoparticles with the substrate (ΔG°<0) and electrochemical potential shifts toward positive values or impact of surface Gibbs free energy of nanoparticles (ΔG°>0) into energy of the system and electrochemical potential shifts toward negative values. The validity of the proposed assumptions is confirmed by good correlation of literature and our experimental data with calculated ones. © Springer-Verlag 2012. Source


Brainina Kh.Z.,Ural State University of Economics | Galperin L.G.,Ural Federal University | Vikulova E.V.,Ural State University of Economics | Stozhko N.Yu.,Ural State University of Economics | And 3 more authors.
Journal of Solid State Electrochemistry | Year: 2011

The article presents the findings of microscopic and electrochemical studies of size-dependent gold particles electrooxidation. Gold particles were immobilized on the surface of carbon-containing screen-printed electrodes. The experiment demonstrated that the transition from macroparticles to nanoparticles caused a shift of the maximum current potential of gold oxidation into the area with more negative potentials. A decrease in particle size resulted in an increase in the electrochemical activity of metal. A positive correlation between experimental and calculated curves confirms a mathematical model (2) and correctness of the calculations. Measured parameters of voltammograms, in particular, maximum current potential, can be used to describe the electrochemical activity and energy properties of nanoparticles. © 2010 Springer-Verlag. Source


Brainina Kh.Z.,Ural State University of Economics | Galperin L.G.,Ural Federal University | Vikulova E.V.,Ural State University of Economics | Galperin A.L.,Ural Federal University
Journal of Solid State Electrochemistry | Year: 2013

The paper proposes a mathematical model describing electrooxidation of a polydisperse system of metal nanoparticles from the surface of an indifferent macro-electrode. It is shown that the degree of dispersion of a nanoparticle ensemble affects the shape of oxidation voltammograms. When the degree of dispersion rises and the average size of nanoparticles becomes smaller, the range of oxidation potentials increases. The results of the experimental study of electrooxidation of gold nanoparticles with different degrees of dispersion are given. The particles were localized on the surface of graphite screen-printed electrodes. A good agreement between the parameters of the experimental and calculated voltammograms confirms the correctness of the proposed model. © 2012 Springer-Verlag. Source

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