Adjustment of model parameters to estimate distribution transformers remaining lifespan

Currently, the electrical system in Argentina is working at its maximum capacity, decreasing the margin between the installed power and demanded consumption, and drastically reducing the service life of transformer substations due to overload (since the margin for summer peaks is small). The advent of the Smart Grids allows electricity distribution companies to apply data analysis techniques to manage resources more efficiently at different levels (avoiding damages, better contingency management, maintenance planning, etc.). The Smart Grids in Argentina progresses slowly due to the high costs involved. In this context, the estimation of the lifespan reduction of distribution transformers is a key tool to efficiently manage human and material resources, maximizing the lifetime of this equipment. Despite the current state of the smart grids, the electricity distribution companies can implement it using the available data. Thermal models provide guidelines for lifespan estimation, but the adjustment to particular conditions, brands, or material quality is done by adjusting parameters. In this work we propose a method to adjust the parameters of a thermal model using Genetic Algorithms, comparing the estimation values of top-oil temperature with measurements from 315 kVA distribution transformers, located in the province of Tucumán, Argentina. The results show that, despite limited data availability, the adjusted model is suitable to implement a transformer monitoring system.Fil: Jimenez, Victor Adrian. Universidad Tecnológica Nacional. Facultad Regional Tucumán. Centro de Investigación en Tecnologías Avanzadas de Tucumán; ArgentinaFil: Will, Adrian L. E.. Universidad Tecnológica Nacional. Facultad Regional Tucumán. Centro de Investigación en Tecnologías Avanzadas de Tucumán; ArgentinaFil: Gotay Sardiñas, Jorge. Universidad Tecnológica Nacional. Facultad Regional Tucumán. Centro de Investigación en Tecnologías Avanzadas de Tucumán; ArgentinaFil: Rodriguez, Sebastian Alberto. Universidad Tecnológica Nacional. Facultad Regional Tucumán. Centro de Investigación en Tecnologías Avanzadas de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentin

The inclusion of SMEs in the Value Chain of the Automotive Industry in Mexico under the Trans-Pacific Treaty (tpp)

Considerando la importancia y multiplicidad de acuerdos comerciales que ha firmado México, la relevancia de la Industria Automotriz en el país, así como la importancia de las Pequeñas y Medianas empresas (pymes) en su contribución al nivel de empleo, se plantea en el presente artículo el estudio de la posibilidad de inclusión de las pymes en la Industria Automotriz, dentro de un esquema de apertura comercial de última generación (El Acuerdo Transpacífico de Cooperación Económica, Trans-PacificPartnership, tpp). Por tanto, el presente artículo tiene por objeto el análisis de la problemática de inclusión de las pymes en la cadena de valor automotriz, dentro de las oportunidades que los acuerdos comerciales pueden generar. Tomando como partida el punto de vista de la teoría del oligopolio y el estudio de las redes globales de producción, se plantea el estudio de las características generales de la red global en la Industria Automotriz, a través del análisis de las empresas armadoras y empresas de autopartes de primer, segundo y tercer nivel y la forma en que se toman las decisiones de ingreso a la red. Se considera además que las armadoras y proveedoras de primer nivel son quienes tienen el papel de líderes de la cadena y, en última instancia, toman las decisiones con respecto al ingreso de nuevos jugadores dentro de la red. Se plantea así, que dadas las características del producto, la red y la forma en la que se llevan a cabo los procesos productivos y la toma de decisiones, resulta inviable y e incluso poco atractivo para las pymes incluirse en la red global de producción automotriz

A new intermediate mass protostar in the Cepheus A HW2 region

We present the discovery of the first molecular hot core associated with an intermediate mass protostar in the CepA HW2 region. The hot condensation was detected from single dish and interferometric observations of several high excitation rotational lines (from 100 to 880K above the ground state) of SO2 in the ground vibrational state and of HC3N in the vibrationally excited states v7=1 and v7=2. The kinetic temperature derived from both molecules is 160K. The high-angular resolution observations (1.25'' x 0.99'') of the SO2 J=28(7,21)-29(6,24) line (488K above the ground state) show that the hot gas is concentrated in a compact condensation with a size of 0.6''(430AU), located 0.4'' (300AU) east from the radio-jet HW2. The total SO2 column density in the hot condensation is 10E18cm-2, with a H2 column density ranging from 10E23 to 6 x 10E24cm-2. The H2 density and the SO2 fractional abundance must be larger than 10E7cm-3 and 2 x 10E-7 respectively. The most likely alternatives for the nature of the hot and very dense condensation are discussed. From the large column densities of hot gas, the detection of the HC3N vibrationally excited lines and the large SO2 abundance, we favor the interpretation of a hot core heated by an intermediate mass protostar of 10E3 Lo. This indicates that the CepA HW2 region contains a cluster of very young stars

Emociones

La presentación aborda las definiciones, autores, factores, funciones y teorias relativas a las emociones y al estrés

Equations of state in soil compression based on statistical mechanics

The authors have published a very interesting contribution in which they present a new and general relationship between void ratio and overburden pressure in the compression process of soils. The study is based on the law of interparticle energy distribution used in statistical mechanics and, in particular, the compression process of a soil is described according to its initial and final void ratios, and to a parameter /? which is related to the potential energy of a soil element. Such potential energy depends not only on the mass and elevation of soil particles, but also on the interactions between them. To account for such interactions, the authors introduce the concept of "imaginary particles", which allows them to use empirically-calibrated P values in the formulation without the need to consider interparticle interactions explicitly. In fact, the results presented by the authors show that such approach reproduces successfully the compression behaviour of a wide range of situations and soils