Radiation-Induced Heterogeneous Processes of Water Decomposition in the Presence of Mixtures of Silica and Zirconia Nanoparticles

The radiation-induced heterogeneous processes of water decomposition on mixtures of silicon dioxide (n-SiO₂) and zirconium dioxide (n-ZrO₂) nanoparticles have been studied. The kinetics of buildup of molecular hydrogen in the radiolytic processes of water decomposition in the test systems has been examined. The reaction rates and the radiation-chemical yield of hydrogen in the radiolysis of water in the presence of n-SiO₂–n-ZrO₂ mixtures with different ratios between the components have been determined. It has been found that the rates and radiation-chemical yields decreased on going from n-ZrO₂ to n-SiO₂. The individual components (n-SiO₂ and n-ZrO₂) and the mixtures of n-SiO₂–n-ZrO₂ and n-SiO₂–n-ZrO₂ + H₂O before and after γ-irradiation have been examined by Fourier-transform IR spectroscopy in order to reveal interactions between the components and to study the mechanism of radiolytic processes. It has been found that the adsorption of water in the test systems occurs via both molecular and dissociative mechanisms. It has been shown that there is no noticeable interaction between the components of the oxide nanoparticles under the conditions of the experiments.     

IR spectroscopy study of the radiation-thermal decomposition of water on nanosized zirconium dioxide

Radiation-thermal decomposition of water on nanosized ZrO₂ in the temperature range of 300–673 K has been studied by FTIR spectroscopy. It has been revealed by the X-ray diffraction method that the sample used has the centrsymmetric monoclinic crystal structure. It has been shown that nanosized zirconium dioxide adsorbs water on via the molecular and dissociative mechanisms. Intermediate products of the radiation-induced heterogeneous decomposition of water, namely, the molecular oxygen and hydrogen peroxide radical ions, zirconium hydride, and hydroxyl radicals have been detected. A comparative analysis of changes in the absorption bands of molecular water and surface hydroxyl groups with temperature has been conducted, and the stimulating role of radiation in the radiation-thermal process of water decomposition has been revealed.     

Temperature Dispersion of Dielectric Characteristics of Composite Materials Based on Polyethylene and Na+-Montmorillonite Nanoclays

Technical Physics - The temperature dispersion of dielectric properties of polyethylene-based composites and nanoclays of the Na+-montmorillonite type is studied. It was found that as a result of...     

Isomerization of n-butane on dealuminated mordenite promoted with zirconium dioxide

Zirconium dioxide promotes the catalytic activity of a dealuminated mordenite in n-butane isomerization. A method is suggested for preparing, without any solvents, a sulfated mordenite-zirconium catalyst active at relatively low temperatures.     

Electrophysical characteristics of nonlinear polymer-silicon composite resistors

The results of analysis of the current-voltage (I–V) characteristic and resistivity of composite resistors (varistors) based on nonpolar propylene and single-crystalline silicon (Si) are considered. The effect of the concentration of the composite components on the IV characteristic and resistivity is detected.     

Three-Body Problem with Variable Masses that Change Anisotropically at Different Rates

In this paper we consider a general case of the three-body problem with variable masses that change anisotropically at different rates. Due to the change of masses reactive forces appear which significantly complicate the problem. Equations of motion of the system have been derived in Jacobi coordinates for the first time. Using these equations of motion and applying the methods of perturbation theory in modified Jacobi and Delaunay elements, we have obtained canonical equations of perturbed motion of the system in the presence of reactive forces. Canonical system of equations for secular perturbations in the three-body problem with variable masses changing anisotropically was derived in explicit form in terms of the analogues of the second system of Poincaré elements. An approximate analytical solution of the differential equations for secular perturbations was obtained by Picard’s method.     

Conversion of Straight-Run Naphtha to C5−C6 Alkanes on Co(Ni)/HZSM–5/SO 4 2- —ZrO2 Composite Catalysts

Russian Journal of Applied Chemistry - The conversion of straight-run naphtha on composite catalytic systems containing HZSM-5 zeolite modified with 0.4 wt % Co or Ni and 15% SZ (10% SO 4 2-...