Induction heating converter's design, control and modeling applied to continuous wire heating

Induction heating is a heating method for electrically conductive materials that takes advantage of the heat generated by the Eddy currents originated by means of a varying magnetic field. Since Michael Faraday discovered electromagnetic induction in 1831, this phenomena has been widely studied in many applications like transformers, motors or generators' design. At the turn of the 20th century, induction started to be studied as a heating method, leading to the construction of the first industrial induction melting equipment by the Electric Furnace Company in 1927. At first, the varying magnetic fields were obtained with spark-gap generators, vacuum-tube generators and low frequency motor-generator sets. With the emergence of reliable semiconductors in the late 1960's, motor-generators were replaced by solid-state converters for low frequency applications. With regard to the characterization of the inductor-workpiece system, the first models used to understand the load's behavior were based on analytical methods. These methods were useful to analyze the overall behavior of the load, but they were not accurate enough for a precise analysis and were limited to simple geometries. With the emergence of computers, numerical methods experienced a tremendous growth in the 1990's and started to be applied in the induction heating field. Nowadays, the development of commercial softwares that allow this type of analysis have started to make the use of numerical methods popular among research centers and enterprises. This type of softwares allow a great variety of complex analysis with high precision, consequently diminishing the trial and error process. The research realized in last decades, the increase in the utilization of numerical modeling and the appearance and improvement of semiconductor devices, with their corresponding cost reduction, have caused the spread of induction heating in many fields. Induction heating equipments can be found in many applications, since domestic cookers to high-power aluminum melting furnaces or automotive sealing equipments, and are becoming more and more popular thanks to their easy control, quick heating and the energy savings obtained. The present thesis focuses on the application of induction heating to wire heating. The wire heating is a continuous heating method in which the wire is continuously feeding the heating inductor. This heating method allows high production rates with reduced space requirements and is usually found in medium to high power industrial processes working 24 hours per day. The first chapters of this study introduce the induction heating phenomena, its modeling and the converters and tanks used. Afterwards, a multichannel converter for high-power and high-frequency applications is designed and implemented with the aim of providing modularity to the converter and reduce the designing time, the production cost and its maintenance. Moreover, this type of structure provides reliability to the system and enables low repairing times, which is an extremely interesting feature for 24 hours processes. Additionally, a software phase-locked loop for induction heating applications is designed and implemented to prove its flexibility and reliability. This type of control allows the use of the same hardware for different applications, which is attractive for the case of industrial applications. This phase-locked loop is afterwards used to design and implement a load-adaptative control that varies the references to have soft-switching according to load's variation, improving converter's performance. Finally, the modeling of a continuous induction wire hardening system is realized, solving the difficulty of considering the mutual influence between the thermal, electromagnetic and electric parameters. In this thesis, a continuous process is modeled and tested using numerical methods and considering converter's operation and influence in the process.Postprint (published version

Cuidados en el sobrepeso y la obesidad infantil

This is the published version of a work that was accepted for publication in Medicina Clínica. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Medicina Clínica 25.6 (2015) DOI: 10.1016/j.tcs.2015.05.00

Southernmost record of Yellow-headed Vulture, <i>Cathartes burrovianus</i> Cassin, 1845 (Cathartiformes, Cathartidae), in Buenos Aires Province, Argentina

We report the southernmost record of Yellow-headed Vulture, Cathartes burrovianus, in Punta Piedras, north-eastern Buenos Aires province, Argentina. This record implies the presence of this species in a new habitat: the Pampas ecoregion. Considering this and other records in Argentina and Uruguay, the species distribution could be extending south from its known range.Facultad de Ciencias Naturales y Muse

Southernmost record of Yellow-headed Vulture, <i>Cathartes burrovianus</i> Cassin, 1845 (Cathartiformes, Cathartidae), in Buenos Aires Province, Argentina

We report the southernmost record of Yellow-headed Vulture, Cathartes burrovianus, in Punta Piedras, north-eastern Buenos Aires province, Argentina. This record implies the presence of this species in a new habitat: the Pampas ecoregion. Considering this and other records in Argentina and Uruguay, the species distribution could be extending south from its known range.Facultad de Ciencias Naturales y Muse

Southernmost record of Yellow-headed Vulture, <i>Cathartes burrovianus</i> Cassin, 1845 (Cathartiformes, Cathartidae), in Buenos Aires Province, Argentina

We report the southernmost record of Yellow-headed Vulture, Cathartes burrovianus, in Punta Piedras, north-eastern Buenos Aires province, Argentina. This record implies the presence of this species in a new habitat: the Pampas ecoregion. Considering this and other records in Argentina and Uruguay, the species distribution could be extending south from its known range.Facultad de Ciencias Naturales y Muse

Bisections of centrally symmetric planar convex bodies minimizing the maximum relative diameter

In this paper we study the bisections of a centrally symmetric planar convex body which minimize the maximum relative diameter functional. We give necessary and sufficient conditions for being a minimizing bisection, as well as analyzing the behavior of the so-called standard bisection.Ministerio de Economía e Innovación MTM2013-48371-C2-1-PJunta de Andalucía FQM-32

Satisfacción de la calidad de servicio del fast food Bembos Chiclayo, 2019

La calidad del servicio es uno de los aspectos más importantes para asegurar la permanencia de las empresas en el mercado; tomando en cuenta que un servicio se considera de calidad cuando logra su fin, el cual es satisfacer las necesidades de los clientes en el presente y en el futuro. La presente tesis planteó como objetivo principal determinar el nivel de calidad del servicio del fast food Bembos 2019. Referente a la metodología, la investigación fue de tipo básica y descriptiva con un enfoque cuantitativo, su diseño es no experimental y la población estuvo conformada por 4320 personas. Para ello, se utilizó el modelo de medición de calidad Servperf (Coin & Taylor) que permitió conocer el grado de calidad de servicio que reciben los clientes. Asimismo, en las dimensiones del servicio: elementos tangibles, fiabilidad, capacidad de respuesta, seguridad y empatía, se elaboró un cuestionario de 22 preguntas para los clientes, la cual se llevó a cabo mediante la técnica de la encuesta y como instrumento de medición el cuestionario tipo Likert. Se pudo obtener como resultados que un 56.66% tomó la opción ni de acuerdo / ni desacuerdo, lo cual es positivo para que puedan trabajar en ello y seguir mejorando. El personal cuenta con una buena disposición para poder brindar un buen servicio, tienen empatía, tratan con amabilidad, son respetuosos, sin embargo necesita capacitación en atención al cliente para poder reforzar sus cualidades y/o habilidades y poder brindarles a los clientes un buen servicio

The effect of age on brain insulin signalling

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 14-07-2017Esta tesis tiene embargado el acceso al texto completo hasta el 14-07-201