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Editorial Complex Optimization and Simulation in Power Systems

In this work, two heuristic techniques used to reduce the number of simulations of lightning-induced voltages, which are required to assess the lightning performance of distribution lines according to the Monte Carlo methodology, are presented. The first uses the Rusck Formula to discard the events that do not cause damage to the line. The second is based on a multi-nonlinear regression of the previously simulated events. Both techniques were applied to estimate the flashover rate of straight and complex lines above flat ground with finite conductivities. As a result, between 80 \% to 90 \% of the total number of simulations were eliminated with a reduced error.

Quarterly sampling campaigns were carried out during year 2019 to study the effects of organic pollution on the diversity and abundance of meiofauna from a polluted coastal system in north-western Mexico. Amongst harpacticoids, the family Miraciidae Dana 1846 was by far the most abundant and diverse, and several new species and the proposal of some new genera of Stenheliinae Brady 1880 and Diosaccinae Sars 1906 will be published elsewhere. Amongst the Diosaccinae, the genus Robertgurneya Apostolov & Marinov 1988 was one of the most abundant. This genus was proposed and diagnosed by Lang (1944, 1948) but after a complex taxonomical history, was made available by Apostolov & Marinov (1988) who proposed an amended diagnosis and designated R. similis similis (Scott A. 1896) as the type species of the genus. Here I propose a new species, Robertgurneya mexicana sp. nov., and give a fully illustrated record of the widely distributed R. rostrata (Gurney 1927). The relationships amongst the species of Robertgurneya are not clear, but the new Mexican species shares with R. falklandiensis (Lang 1936) the elongated inner dimorphic spine on the basis of the male P1. Additionally, a new amended diagnosis for the genus Robertgurneya, as well as the reallocation of R. soyeri (Apostolov 1974) into Typhlamphiascus Lang 1944, and the creation of a new genus, Robertgurneyella gen. nov., for R. spinulosa (Sars 1911) are proposed. 

The present paper develops a methodology to choose the best connection scheme for traction substations of a Massive Electrical Railway System (MERS) and distribution substations in urban areas using graph theory and economical optimization.

In this work, the Monte Carlo method (MC) was extended to simulate the packing and segregation of particles subjected to a gravitational field and confined inside rigid walls. The method was used in systems containing spheres inside cylinders. The calculation of void fraction profiles in both the axial and radial directions was formulated, and some results are presented. In agreement with experimental data, the simulations show that the packed beds present structural ordering near the cylindrical walls up to a distance of about 4 particle diameters. The simulations also indicate that the presence of the cylindrical wall does not seem to have a strong effect on the gravitational segregation phenomenon.

Este artículo presenta el estado actual de las técnicas de inteligencia artificial y su aplicación al campo de la detección y diagnóstico de fallas en sistemas dinámicos. Inicialmente, se hace una breve descripción de lo que se considera un mecanismo de detección y diagnóstico de fallas, y se explican los enfoques actuales de estudio y aplicación de tales mecanismos. Posteriormente, se presentan los resultados más importantes de las diferentes técnicas de inteligencia artificial aplicadas a la detección y diagnóstico de fallas. Finalmente, se presenta un análisis comparativo con base en las características deseables de los mecanismos de detección y diagnóstico de fallas. El artículo concluye mencionando los beneficios de la clasificación de las técnicas presentadas y enumerando las posibles vías hacia donde debe ir la investigación en este campo.

Radiative heat transfer in a 1 kW cavity-type solar reactor devoted to the thermal reduction of compressed ZnO and SnO2 powders is analyzed by a Monte Carlo ray tracing simulation. The developed model takes into account the radiative properties of the reactant particles and of the ceramic cavity walls, as well as the angular intensity distribution of the incoming concentrated solar irradiation. The model also includes the conduction heat losses through the lateral walls and the energy consumed by the endothermic chemical reaction. It is used to predict the temperature and the absorbed flux density profiles on the inner cavity walls for different main features of the reactor, concerning the dimensions of the cavity and the type of reactant. Results show that the absorbed flux density profile and the theoretical thermochemical efficiency change with the cavity aspect ratio and with the oxide reactant. The cavity with an aspect ratio of 3 and a SnO2 pellet undergoing dissociation presents the highest thermochemical efficiency. Additionally, a different configuration of the reactor design is considered, which consists in implementing a layer of reactive particles on the inner lateral cavity wall. The model highlights that this type of reactor operation with a reactant layer on the lateral cavity wall results in an improved thermochemical efficiency.