The wireless charging system for mining electric locomotives

The electric vehicles development has a high potential for energy saving: an energy-saving traffic control can reduce energy resource consumption, and integration with the power grid provides the ability of daily load pattern adjustment. These features are also relevant for underground mining. The critical element of vehicle-to-grid integration is the charging infrastructure, where wireless charging is promising to develop. The implementation of such systems in underground mining is associated with energy efficiency issues and explosion safety. The article discusses the development and research of a wireless charging system for mining electric locomotive A-5.5-600-U5. The analytic hierarchy process is used for justification of the circuitry and design solution by a comparison of different technical solutions based on energy efficiency and safety criteria. A complex computer model of the wireless charging system has been developed that gives the transients in the electrical circuit of a wireless charging system and the high-frequency field density distribution near the transmitting and receiving coils in a 3D setting. An approach to ignition risk evaluation based on the analysis of high-frequency field density in the charging area between the coils of the wireless charging system is proposed. The approach using a complex computer model is applied to the developed system. The study showed that the wireless charging system for mining electric locomotives operating in the gaseous-and-dusty mine is technically feasible and there are designs in which it is explosion safe

A DFT Study of Direct Oxidation of Benzene to Phenol by N 2

Density functional theory (DFT) calculations were carried out in a study of the mechanism of benzene oxidation by N2O to phenol over an extra framework dimeric [FeOFe]2+ species in ZSM-5 zeolite represented by a [Si6Al2O9H14(Fe(µ-O)Fe)] cluster model. The catalytic reactivity of such a binuclear species is compared with that of mononuclear Fe2+ and (FeO)+ sites in ZSM-5 investigated in our earlier works at the same level of theory (J. Phys. Chem. C2009, 113, 15307; 2010, 114, 12580). The activation energies for the elementary reaction step involved in the benzene hydroxylation over the binuclear and the mononuclear iron sites are comparable. The major difference in the catalytic behavior of the systems considered is related to the ability of Fe3+-containing sites to promote side reactions leading to the active site deactivation. Regeneration of the active site via the phenol desorption is much less favorable than its dissociation resulting in the formation of very stable grafted phenolate species on both the [Fe(µ-O)Fe]2+ and (FeO)+ sites. In the case of Fe2+ sites such an alternative reaction path does not exist resulting in their stable catalytic performance. Benzene hydroxylation and phenol formation over the binuclear (Fe(µ-O)Fe)2+ sites in ZSM-5 are promoted in the presence of water. These computational findings are consistent with the experimental observations and allow their rationalization at the molecular level