Voronezh State Technical University (Russian: Воронежский государственный технический университет) is a public university located in Voronezh, Russia..
This study presents a comprehensive investigation of the CoFe2O4–Pb2ScNbO6 (0.5CFO–0.5PSN) composite, synthesized via a solid-state reaction method. The composite, comprising a ferrite spinel and a relaxor ferroelectric, was characterized using a suite of techniques including dielectric spectroscopy, optical analysis, X-ray diffractometry, magnetometry, magnetodielectric measurements and electrocatalytic testing. At room temperature, the real part of the complex permittivity (ε′) attains a value of 105. Within the temperature range of 100–250 °C, ε′ increases significantly to approximately 1.4 × 106. The temperature dependence of permittivity, ε′(T), exhibits a relaxor behaviour, which is attributed to the diffuse phase transition inherent to the PSN component and contributions from Maxwell–Wagner interfacial polarization. A distinct anomaly in the ε′(T) curve is observed near 450 °C, manifested as a kink followed by a sharp increase. This feature is associated with the transition of the CFO component from a ferrimagnetic to a paramagnetic state. The analysis of the magnetoresistance coefficient, MR(H), reveals that the composite exhibits colossal magnetoresistance (CMR) on the order of 530
The effects of reinforcement type (steel cable and mesh, glass roving and mesh) and aggregate type (sand and limestone powder) on the shrinkage of 3D printed concrete were determined. To simulate different drying conditions of the material in thin layers of 3D printed structures, 3D printed plate samples were used and kept in environments with relative humidity of 30
The dielectric response dispersion in the solid solution 0.9Pb0.95Sr0.05(Zr0.52Ti0.48)O3–0.05Pb(Zn1/3Nb2/3)O3–0.05Pb(Mn1/3Sb2/3)O3 + 0.1 mol
The analysis of the reduction of the dimensionality of the initial statistical data was carried out using the cluster rule with grouping of independent parameters to ensure the arrangement of their average value in groups in ascending order. This made it possible to formulate the problem of finding the coefficients of the linear equation of spatial regression, which was solved by projecting the values of the dependent variable onto coordinate planes using the least squares method and the objective function in the form of superpositions of squared deviations. Projecting one of the regression equations of the 2-D format onto a plane parallel to the axis of the values of the dependent variable made it possible to identify a straight line in space through a parametric regression equation. An example of calculation is given.
The article presents the results of an experimental study of the dependence of the hydraulic resistance of a fixed dense and fluidized bed of a material on the particle size in a dispersed system. It has been found that the hydraulic resistance of the dense layer increases with increasing particle size and is practically independent of it in the fluidized state. An increase in the mass of the material in the working chamber leads to an increase in the hydraulic resistance of the layer. In the fluidized state, the hydraulic resistance of the layer also increases slowly with increasing air velocity.
