Switching-Cell Arrays - An Alternative Design Approach in Power Conversion

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThe conventional design of voltage-source power converters is based on a two-level half-bridge configuration and the selection of power devices designed to meet the full application specifications (voltage, current, etc.). This leads to the need to design and optimize a large number of different devices and their ancillary circuitry and prevents taking advantage from scale economies. This paper proposes a paradigm shift in the design of power converters through the use of a novel configurable device consisting on a matrix arrangement of highly-optimized switching cells at a single voltage class. Each switching cell consists of a controlled switch with antiparallel diode together with a self-powered gate driver. By properly interconnecting the switching cells, the switching cell array (SCA) can be configured as a multilevel active-clamped leg with different number of levels. Thus, the SCA presents adjustable voltage and current ratings, according to the selected configuration. For maximum compactness, the SCA can be conceived to be only configurable by the device manufacturer upon the customer needs. For minimum cost, it can also be conceived to be configurable by the customer, leading to field-configurable SCAs. Experimental results of a 6x3 field-configurable SCA are provided to illustrate and validate this design approach.Peer ReviewedPostprint (author's final draft

Movimientos sociales: ¿Último bastión de la izquierda latinoamericana?

Reseña de: Petras, James y Veltmeyer, Henry (2005), Social Movements and State Power. Argentina, Brazil, Bolivia, Ecuador, Pluto Press, Londre

El vínculo ideacional entre la democracia y el Mercosur

Reseña de: Gardini, Gian Luca, The Origins of Mercosur. Democracy and Regionalization in South America, Ed. Palgrave Macmillan, febrero de 2010

Síntesi de nous complexes de coordinació 3d o 4f amb bases de Schiff. Estudi estructural i magnètic

Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2021, Tutor: Mohammed Salah El FallahThe main goal of this work was to obtain 3d and 4f polynuclear coordination compounds with Schiff bases as ligands and the study of their magnetic and structural properties. A few trials were carried out using Ni(II), Mn(II), Cu(II), Gd(III) and Dy(III), although only two compounds using Cu(II) and Mn(II) were able to crystallize. Their structures were successfully determined by X-ray diffraction. The copper compound crystallized as a dinuclear unit with formula C30H30Cl2Cu2N6O14, and a monomeric unit with formula C15H17Cl2CuN3O3 that co-crystallizes in the same crystal structure. The manganese complex was a dinuclear complex with formula C30H34Cl2Mn2N6O4 bridged by two chloride anions. Instead of the desired Schiff base, two new types of ligands were obtained due to an unexpected cyclization of one of the hydroxy groups leading to an oxazolidine ring in the first compound, and a rare double oxazolidine ring ligand that is able to complex the manganese (II) atoms in the second compound. Magnetic susceptibility measures were performed for both compounds. Compound 1 exhibits a weak antiferromagnetic coupling between the two Cu(II) metal ions, with an exchange constant J=-0.67 cm-1. Compound 2 exhibits a very weak antiferromagnetic coupling between the two Mn(II) metal ions, with an exchange constant J=-0.24 cm-

Paleoneuroanatomy of the European lambeosaurine dinosaur Arenysaurus ardevoli

The neuroanatomy of hadrosaurid dinosaurs is well known from North America and Asia. In Europe only a few cranial remains have been recovered that include the braincase. Arenysaurus is the first European endocast for which the paleoneuroanatomy has been studied. The resulting data have enabled us to draw ontogenetic, phylogenetic and functional inferences. Arenysaurus preserves the endocast and the inner ear. This cranial material was CT scanned, and a 3D-model was generated. The endocast morphology supports a general pattern for hadrosaurids with some characters that distinguish it to a subfamily level, such as a brain cavity that is anteroposteriorly shorter or the angle of the major axis of the cerebral hemisphere to the horizontal in lambeosaurines. Both these characters are present in the endocast of Arenysaurus. Osteological features indicate an adult ontogenetic stage, while some paleoneuroanatomical features are indicative of a subadult ontogenetic stage. It is hypothesized that the presence of puzzling mixture of characters that suggest different ontogenetic stages for this specimen may reflect some degree of dwarfism in Arenysaurus. Regarding the inner ear, its structure shows differences from the ornithopod clade with respect to the height of the semicircular canals. These differences could lead to a decrease in the compensatory movements of eyes and head, with important implications for the paleobiology and behavior of hadrosaurid taxa such as Edmontosaurus, Parasaurolophus and Arenysaurus. The endocranial morphology of European hadrosaurids sheds new light on the evolution of this group and may reflect the conditions in the archipelago where these animals lived during the Late CretaceousPeer ReviewedPostprint (published version

From the quest for autonomy to the dual break: Structural and agential changes in Brazil’s foreign policy during the 21st century

Informed by an understanding that the quest for autonomy can serve as a compass of Brazil’s foreign policy, this paper undertakes an extensive interpretative analysis of the concept in relation to the agency/structure debate. Our aim is to use these theoretical tools to analyse Brazil’s international action during the 21st century, paying special attention to Bolsonaro’s administration. This article argues that we are witnessing a dual break in autonomy: an essentially structural break related to the underlying trends currently redesigning the international world as we know it, and another more agential break, resulting from president Bolsonaro’s particular worldviewWe thank to the funding received from Aristos Campus Mundus. Campus of International Excellence (ACM2019_16

Review of Arte Escrita. Texto, imagen y género en el arte contemporáneo, (M. Méndez Baiges, ed.), Granada: Comares

Review of the book Arte Escrita, which -coordinated by Maite Méndez Baiges- offers us a tour of the text and image in contemporary art from the point of view of gender

UNASUR y la perspectiva estadocéntrica de seguridad en Sudamérica

Over the last few decades we have witnessed an emerging interest in security topics and mechanisms to analyse these. In the context of globalization, new threats have appeared (not only interstate, but mainly, intra- and trans-state), as well as theoretical approaches (such as Critical Security Studies, CSS) to deal with them. Regarding the South American region it is useful to consider the constitution of the Unasur as a forum to coordinate policies with a very relevant geostrategic and security influence. In this paper, I deal with the logics that motivated the birth of the UNASUR project, in order to examine the way this regional project acts against different types of security threats and regional crises until 2016-17, when Venezuelan crises escalated. Furthermore, empirical evidences are tested with the common characteristics proposed by Peoples and Vaughan-Williams for the CSS. Some conclusions are drawn as new aspects have been incorporated to the way UNASUR addressed regional conflicts (security as a derivate concept and a broader security agenda), while an important element remained the same: a state-centric perspective.En las últimas décadas hemos asistido a un creciente interés por los temas de seguridad y cómo analizarlos. En el marco de la globalización, han surgido nuevas amenazas (no sólo interestatales, sino también intra- y trans-estatales), así como nuevos enfoques teóricos para abordarlos (como los Estudios Críticos de Seguridad, CSS). En lo que concierne a la región sudamericana resulta oportuno entender el surgimiento de la UNASUR como un foro de coordinación de políticas con una importante relevancia geoestratégica y de seguridad. En este trabajo, se abordan las lógicas que motivaron el nacimiento de la UNASUR, con la intención de analizar cómo este proyecto regional se ha comportado ante los distintos tipos de amenazas de seguridad y las crisis regionales hasta el año 2016-17 con la escalada de la crisis venezolana. Además, se evalúan y testan las evidencias empíricas en contraste con las tres características comunes de los CSS que señalan Peoples y Vaughan-Williams. Finalmente, se extraen algunas conclusiones sobre las nuevas particularidades y prácticas que la UNASUR ha introducido a la hora de lidiar con conflictos regionales (seguridad como concepto derivativo y la ampliación de la agenda de seguridad), mientras que, por el contrario, el tercer componente permanecía igual: una perspectiva estadocéntrica

Mitificación y desmitificación de las independencias americanas: Bolívar y San Martín

Review-Essay de: • LYNCH, John, San Martín. Argentine Soldier, American Hero, Yale University Press, New Haven y Londres, 2009. • LYNCH, John, Simón Bolívar. A Life, Yale University Press, New Haven y Londres, 2006. • MADARIAGA, Salvador de, Bolívar, Espasa-Calpe, Madrid, 1975, [1951]