Entity

Time filter

Source Type


Rybin O.,Kharkiv State University of Food Technology and Trade | Raza M.,Bahauddin Zakariya University
International Journal of Applied Electromagnetics and Mechanics | Year: 2010

Analytical and numerical optimization method for evaluating the complex effective dielectric and magnetic constants of elementary flat slab of metamaterial is presented. The minimization problem is solved for a cascaded network representation of the slab utilizing the Effective Medium Theory. The algorithm is benchmarked using the free Meep FDTD software package. © 2010 - IOS Press and the authors. All rights reserved. Source


Zolochevsky A.,Kharkiv Polytechnic Institute | Parkhomenko L.,Kharkiv State University of Food Technology and Trade | Kuhhorn A.,TU Brandenburg
Materials Chemistry and Physics | Year: 2012

The effects of oxygen exchange kinetics at the oxygen-lean side of the perovskite-type hollow fiber membrane for oxygen separation from air, on chemical stresses, as well as those from bulk oxygen transport, are studied. Closed-form analytical solutions for oxygen permeation flux at steady state in the fiber lumen, and for the distribution of oxygen non-stoichiometry and chemical stresses in a transient state in the hollow fiber membrane have been obtained. Different operating modes of the Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3-δ hollow fiber membrane module to produce oxygen from air at 1173 K have been considered including sweep-gas operation, high-pressure operation and vacuum operation. Values of the chemical surface exchange coefficient in the broad range of oxygen partial pressure and the chemical diffusion coefficient have been determined from the permeation measurements. Values of the oxygen non-stoichiometry on both sides of the Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3-δ hollow fiber at equilibrium with the surrounded atmosphere have been obtained from the experimental data for different operating modes of membrane module. Chemical stresses in the hollow fibers of the module with three operating modes have been calculated. Practical recommendations on how to improve the performance and operating conditions, as well as, to avoid membrane break have been formulated. Investigations have shown that influence of oxygen surface exchange kinetics on chemical stresses increases strongly with decreasing the hollow fiber membrane thickness. © 2012 Elsevier B.V. All rights reserved. Source


Rybin O.,Kharkiv State University of Food Technology and Trade
International Journal of Applied Electromagnetics and Mechanics | Year: 2012

The complex effective relative permeability of a two-component ferrite-like metamaterial was studied for the two cases of electromagnetic wave propagation with respect to direction of dc magnetic bias field, namely, parallel and transverse. The metamaterial of interest is the host dielectric with periodically embedded ferric cylindrical or spherical inclusions. The inclusions are saturated with the biasing magnetic field and the magnetic losses are taken into account. The analysis was performed utilizing the Microwave Effective Medium Theory for two-component artificial composite materials with saturated lossless ferric inclusions [1]. Computations revealed that low values of refractive index as well as negative values of permeability can be achieved. © 2012-IOS Press and the authors. All rights reserved. Source


Rybin O.,Kharkiv State University of Food Technology and Trade | Rybin O.,Kharkov National Academy of Municipal economics
International Journal of Applied Electromagnetics and Mechanics | Year: 2012

In the paper, the possibility of achieving negative permeability for two-component metamaterials is analytically proven. The metamaterial media are presented as an infinite host dielectric material (air) with periodically embedded ferric cylindrical and spherical inclusions saturated with a biasing external magnetic field. The appropriate frequency-dependent inequalities are obtained in the frequency range where permeability becomes negative. The cases when electromagnetic wave propagates parallel and transverse to the direction of biasing magnetic field are studied. © 2012 - IOS Press and the authors. All rights reserved. Source


Rybin O.,Kharkiv State University of Food Technology and Trade
International Journal of Applied Electromagnetics and Mechanics | Year: 2011

In this paper, Effective Medium Theory for two-component metamaterial media as infinite host dielectric medium embedded periodically with cylindrical iron inclusions and spherical ones saturated with an external biasing magnetic field is developed in the microwave frequencies. The long wave approximation of effective permeability tensors for the considered metamaterial media has been obtained using the microwave extension of Effective Medium Approximation for polycrystalline ferrites and the long wave approximation of expressions of the effective magnetic permeability for two-component undiluted metal-dielectric composites with infinitely long non-magnetic metal cylindrical and spherical inclusions. The effective magnetic properties of the metamaterial media for the case of microwave propagation transverse to bias have been studied. It is shown that the considered metamaterial can exhibit the ultra-low refractive index phenomenon and the phenomenon of negative magnetic permeability for the case of microwave propagation transverse to bias. © 2011 ? IOS Press and the authors. Source

Discover hidden collaborations