Magnetic vector potential and magnetic field intensity due to a finite current carrying cylinder considering a variable current density along its axial dimension

With the aim of introducing a computationally efficient solution for problems such as the fast computation of magnetic field magnitudes and forces in coils and windings, this paper presents analytical expressions for the magnetic vector potential and magnetic field intensity in radial and axial directions due to a finite cylinder with infinitesimal wall thickness carrying a linearly varying current density between the values at the lower and upper ends. All expressions have been derived in terms of complete elliptic integrals of first, second and third kind, whose evaluation is achieved by means of very fast algorithms. The formulas presented make possible the fast computation of magnetic field at any point in space at reduced computational cost. The formulation is not only specially suited for modeling the current distribution in foil windings of power transformers but also for representing the magnetization of transformer core legs. The present method is also useful for efficient modeling of cylinders with constant current density since it is a generalization of this especial case. Finally, an example is presented where the results achieved using the proposed method are compared with those obtained using the finite element method showing a very good agreement between them.Fil: Díaz, Guillermo A.. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; ArgentinaFil: Mombello, Enrique Esteban. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Stephan, Voss. No especifíca

Expert system for the assessment of power transformer insulation condition based on type-2 fuzzy logic systems

An efficient expert system for the power transformer condition assessment is presented in this paper. Through the application of Duval's triangle and the method of the gas ratios a first assessment of the transformer condition is obtained in the form of a dissolved gas analysis (DGA) diagnosis according IEC 60599. As a second step, a knowledge mining procedure is performed, by conducting surveys whose results are fed into a first Type-2 Fuzzy Logic System (T2-FLS), in order to initially evaluate the condition of the equipment taking only the results of dissolved gas analysis into account. The output of this first T2-FLS is used as the input of a second T2-FLS, which additionally weighs up the condition of the paper-oil system. The output of this last T2-FLS is given in terms of words easily understandable by the maintenance personnel. The proposed assessing methodology has been validated for several cases of transformers in service. © 2011 Elsevier Ltd. All rights reserved.Fil: Flores, Wilfredo C.. Universidad Nacional Autónoma de Honduras; Honduras. Universidad Nacional de San Juan; ArgentinaFil: Mombello, Enrique Esteban. Universidad Nacional de San Juan; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Jardini, José. A.. Universidade de Sao Paulo; BrasilFil: Rattá Gutiérrez, Giuseppe Aníbal. Universidad Nacional de San Juan; ArgentinaFil: Corvo, Antonio M.. Companhia de Transmissão de Energía Elétrica Paulista; Brasi

Gastrointestinal electric stimulation in the dog

Los autores utilizando un marcapaso intestinal Modelo M. 1 100 aplicaron estímulos eléctricos en forma directa sobre la mucosa del tubo digestivo (estómago, yeyuno, colon) de perros logrando aumentar el peristaltismo tanto en tiempo como en intensidad de contracción con un franco incremento del tono entre los estímulos. Asimismo después de 5 a 6 horas de provocar choques eléctricos en forma ininterrumpida comprobaron que no se presentaban signos de agotamiento. En base a ello concluyen que el método es útil e inocuo en los cuadros de ileo paralítico de las más diversas etiologías tanto en humanos como en animales.The authors had been used an intestinal passmaker Model M. 1.100, electric stimulation were applied directly over digestive tube mucosal (stomach, yeyun and colon) on dogs. Success were found on peristaltism frequency on time and contraction intensity with increase of tone between stimulations. After 5 to 6 hours of electric shock in continuous form were proved that no sign of exhausted were present. On this base was concluded that the method is useful and not cause damages in paralytic ileum cause by different etiologies in human and animals.Facultad de Ciencias Veterinaria

An approach to dynamic line rating state estimation at thermal steady state using direct and indirect measurements

Dynamic line rating has emerged as a solution for reducing congestion in overhead lines, allowing the optimization of power systems assets. This technique is based on direct and/or indirect monitoring of conductor temperature. Different devices and methods have been developed to sense conductor temperature in critical spans. In this work, an algorithm based on WLS is proposed to estimate temperature in all ruling spans of an overhead line. This algorithm uses indirect measurements - i.e. weather reports and/or downscaling nowcasting models as inputs as well as direct measurements of mechanical tension, sag and/or conductor temperature. The algorithm has been tested using typical atmospheric conditions in Iceland along with an overhead line´s real design, showing robustness, efficiency and the ability to minimize error in measurements.Fil: Alvarez, David L.. Universidad Nacional de Colombia; ColombiaFil: Faria da Silva, F.. Aalborg Universitet; DinamarcaFil: Mombello, Enrique Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Energía Eléctrica. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; ArgentinaFil: Bak, Claus Leth. Aalborg Universitet; DinamarcaFil: Rosero, Javier A.. Universidad Nacional de Colombia; ColombiaFil: Ólason, Daníel Leó. Landsnet; Islandi

Gastrointestinal electric stimulation in the dog

Los autores utilizando un marcapaso intestinal Modelo M. 1 100 aplicaron estímulos eléctricos en forma directa sobre la mucosa del tubo digestivo (estómago, yeyuno, colon) de perros logrando aumentar el peristaltismo tanto en tiempo como en intensidad de contracción con un franco incremento del tono entre los estímulos. Asimismo después de 5 a 6 horas de provocar choques eléctricos en forma ininterrumpida comprobaron que no se presentaban signos de agotamiento. En base a ello concluyen que el método es útil e inocuo en los cuadros de ileo paralítico de las más diversas etiologías tanto en humanos como en animales.The authors had been used an intestinal passmaker Model M. 1.100, electric stimulation were applied directly over digestive tube mucosal (stomach, yeyun and colon) on dogs. Success were found on peristaltism frequency on time and contraction intensity with increase of tone between stimulations. After 5 to 6 hours of electric shock in continuous form were proved that no sign of exhausted were present. On this base was concluded that the method is useful and not cause damages in paralytic ileum cause by different etiologies in human and animals.Facultad de Ciencias Veterinaria

Metodi e tecniche dell'anatomia patologica

Materiali in anatomia patologica, fissazione, analisi macroscopica, analisi microscopica, cenni sulle analisi molecolari