Structure and Properties of Nanostructured YBa<Subscript>2</Subscript>Cu<Subscript>3</Subscript>O<Subscript>7–δ</Subscript>, BiFeO<Subscript>3</Subscript>, and Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>

The development of new nanostructured materials based on YBa₂Cu₃O_7–δ, BiFeO₃, and Fe₃O₄ compounds is considered. The structure, morphology, and properties of these materials are studied. The possibilities of fabricating YBa₂Cu₃O_7–δ ceramics with given densities from nanopowders in a single stage by an energy efficient method and growing superconducting films of the same composition on a silicon substrate (on a SiO₂ layer) are demonstrated. The technique for fabricating BiFeO₃ nanopowder, making it possible to obtain nanostructured ceramics without additional accompanied phases commonly forming during BiFeO₃ synthesis is developed. Two methods of the single-stage synthesis of Fe₃O₄ nanopowder are presented: burning of nitrate-organic precursors and the electrochemical three-electrode method in which one of the electrodes, i.e., an anode containing scrap iron and slurry, is used as an expendable material.     

Fast Iterative Method with a Second-Order Implicit Difference Scheme for Time-Space Fractional Convection–Diffusion Equation

In this paper we intend to establish fast numerical approaches to solve a class of initial-boundary problem of time-space fractional convection–diffusion equations. We present a new unconditionally stable implicit difference method, which is derived from the weighted and shifted Grünwald formula, and converges with the second-order accuracy in both time and space variables. Then, we show that the discretizations lead to Toeplitz-like systems of linear equations that can be efficiently solved by Krylov subspace solvers with suitable circulant preconditioners. Each time level of these methods reduces the memory requirement of the proposed implicit difference scheme from \({\mathcal {O}}(N^2)\) to \({\mathcal {O}}(N)\) and the computational complexity from \({\mathcal {O}}(N^3)\) to \({\mathcal {O}}(N\log N)\) in each iterative step, where N is the number of grid nodes. Extensive numerical examples are reported to support our theoretical findings and show the utility of these methods over traditional direct solvers of the implicit difference method, in terms of computational cost and memory requirements.     

An indirect approach for egg weight sorting using image processing

An indirect approach for egg weight sorting, using image processing, is proposed in the paper. The eggs are sorted in four classes by weight. Regression analysis is used for approximation of relationship between egg weight and egg geometric parameters—perimeter, area, major and minor axis, shape index and shape factor. The values of the geometric parameters, collected by image processing and the one, collected by traditional method, are compared for each egg sample, using percent differences between data. The experimental results show that the most significant parameter for egg weight indirect measurement is the egg area, with correlation coefficient 0.989. The mathematical model for the relationship between weight and area of the egg is defined with coefficient of determination 0.978. The classification accuracy is achieved within the eggs test sample sorting. The total classification error is 2.5% for test set and 12.5% for training set.     

Simulation of drift-diffusion transport of charge carriers in semiconductor layers with a fractal structure in an alternating electric field

Based on the fractional-order partial differential equation, the diffusion-drift charge-carrier transport in a semiconductor layer with a fractal structure under a longitudinal alternating electric field is simulated. The simulation showed that the space–time distributions of carriers are broadened and asymmetric in layers with a fractal structure. Under certain conditions, the effect of charge oscillation frequency doubling in an external alternating electric field is observed.