Two Globally Convergent Adaptive Speed Observers for Mechanical Systems

A globally exponentially stable speed observer for mechanical systems was recently reported in the literature, under the assumptions of known (or no) Coulomb friction and no disturbances. In this note we propose and adaptive version of this observer, which is robust vis--a--vis constant disturbances. Moreover, we propose a new globally convergent speed observer that, besides rejecting the disturbances, estimates some unknown friction coefficients for a class of mechanical systems that contains several practical examples

Avances y desafíos de la formación investigativa en la carrera de Pedagogía de la Universidad Politécnica Salesiana de Ecuador

El presente ensayo es una aproximación inicial a la formación investigativa de la Carrera de Pedagogía de la Universidad Politécnica Salesiana de Ecuador (UPS) y fue elaborado como una exigencia del curso “Problemas sociales de la ciencia y la tecnología” impartido en la ciudad de la Habana como parte del doctorado en Ciencias Pedagógicas que el autor se encuentra cursando. El enfoque teórico utilizado es el del campo Ciencia, Tecnología y Sociedad (CTS) a través del cual se procura evidenciar las interrelaciones entre la investigación, la ciencia, la tecnología y el contexto histórico-social que configuran este complejo entramado

La Universidad Politécnica Salesiana en el proceso de rediseño curricular del consejo de educación superior del Ecuador

La sociedad ecuatoriana sigue con marcado interés el proceso de transformación de la matriz productiva auspiciada por el Gobierno actual. El Plan Nacional de Desarrollo ha señalado la pauta para ello y se espera que en el mediano plazo se vean los efectos de esta iniciativa. Un sector estratégico para este cambio lo constituye la educación superior, la misma que bajo las directrices del Consejo de Educación Superior (CES) empezó, desde hace algún tiempo atrás, el rediseño curricular de sus ofertas educativas. La Universidad Politécnica Salesiana (UPS) asumió de manera entusiasta y cívica este reto, pero en el camino se ha encontrado con algunos escollos que rebasan las dificultades normales que se pueden presentar en este tipo de esfuerzos y que por sus repercusiones generan un cierto nivel de preocupación e incertidumbre y que deben ser analizados con el filtro de la teoría pedagógica y los valores que guían la práctica educativa de nuestra institución

The Legal Implications of Anti-LGBTQ+ Curriculum Laws

Last March 2022, Florida’s Governor Ron DeSantis passed and enacted the Parental Rights in Education Act, which then became known as the infamous “Don\u27t Say Gay” bill. The bill bans instruction on sexual orientation and gender identity “before the 4th grade and requires such instruction to be ‘age-appropriate or developmentally appropriate.” The language of the bill itself is vague and broad and doesn’t provide clarity about the law’s compliance with non-discrimination and first amendment rights. Critics argue that the statute doesn’t define the meaning of “classroom instruction” or what constitutes “age-appropriate” or “developmentally appropriate” instruction, which leaves questions regarding the scope of the law. The “Don\u27t Say Gay” bill was based on the idea that parents have the fundamental right to make decisions regarding when and how their children should be introduced to certain topics, specially LGBTQ+ rights and history. The law, by default, stigmatizes the identities of LQGBTQ+ students, teachers and administrators and encourages them to hide who they are out of fear of retaliation by intolerant parents. Furthermore, the “Don\u27t Say Gay” bill inherently prevents teachers from educating children productively and introducing them to topics that are essential to their development. This post was originally published on the Cardozo Journal of Equal Rights and Social Justice website on April 3, 2023. The original post can be accessed via the Archived Link button above

Improving the Performance of Low Voltage Networks by an Optimized Unbalance Operation of Three-Phase Distributed Generators

This work focuses on using the full potential of PV inverters in order to improve the efficiency of low voltage networks. More specifically, the independent per-phase control capability of PV three-phase four-wire inverters, which are able to inject different active and reactive powers in each phase, in order to reduce the system phase unbalance is considered. This new operational procedure is analyzed by raising an optimization problem which uses a very accurate modelling of European low voltage networks. The paper includes a comprehensive quantitative comparison of the proposed strategy with two state-of-the-art methodologies to highlight the obtained benefits. The achieved results evidence that the proposed independent per-phase control of three-phase PV inverters improves considerably the network performance contributing to increase the penetration of renewable energy sources.Ministerio de Economía y Competitividad ENE2017-84813-R, ENE2014-54115-

La Manga Bordada del Corpus de la Catedral de Toledo.

Sin resume

Yielding of rockfill in relative humidity-controlled triaxial experiments

The final publication is available at Springer via http://dx.doi.org/10.1007/s11440-016-0437-9The paper reports the results of suction controlled triaxial tests performed on compacted samples of two well graded granular materials in the range of coarse sand-medium gravel particle sizes: a quartzitic slate and a hard limestone. The evolution of grain size distributions is discussed. Dilatancy rules were investigated. Dilatancy could be described in terms of stress ratio, plastic work input and average confining stress. The shape of the yield locus in a triaxial plane was established by different experimental techniques. Yielding loci in both types of lithology is well represented by approximate elliptic shapes whose major axis follows approximately the Ko line. Relative humidity was found to affect in a significant way the evolution of grain size distribution, the deviatoric stress-strain response and the dilatancy rules.Peer ReviewedPostprint (author's final draft