Aplicación de un ciclo de mejora docente en Dinámica de la partícula

En esta comunicación se describe el diseño, aplicación y evaluación de un ciclo de mejora docente (CMD) realizado en la asignatura de Física I del Grado de Ingeniería Electrónica Industrial de la Universidad de Sevilla. En concreto, el ciclo se ha llevado a cabo durante el Tema 3 de la asignatura que trata sobre dinámica de la partícula. A lo largo de todo el ciclo se ha buscado conseguir un aprendizaje crítico por parte de los alumnos. Para ello, se han diseñado actividades con el objetivo de que los alumnos se replantearan conceptos previamente establecidos y fueran capaces de evaluar sus conocimientos. Por otro lado, también se ha intentado fomentar el trabajo en grupo mediante la realización de un taller basado en la resolución de un problema. Por último, el progreso de aprendizaje a lo largo del ciclo se ha evaluado mediante el uso de un cuestionario inicial y final

Analysis and synthesis of leaky-wave devices in planar technology

[ESP] ] El trabajo llevado a cabo durante la realización de esta tesis doctoral, se ha centrado en el análisis y síntesis de dispositivos de microondas en tecnología planar. En concreto, se han estudiado diferentes tipos de dispositivos basados en radiación por ondas de fuga "leaky waves", en los cuales las propiedades de radiación están determinadas por la constante de fase del modo "leaky" que es el que determina el ángulo de apuntamiento y por la tasa de radiación que es la que determina la intensidad de los campos radiados. De esta manera, controlando en amplitud y fase el modo "leaky" se puede obtener un control efectivo sobre el diagrama de radiación del dispositivo. Además, con el objetivo de poder obtener de una manera más eficiente las características de propagación de los modos de fuga "leaky" en función de los principales parámetros geométricos de la estructura, se han desarrollado diversas herramientas de análisis modal basadas en la técnica de resonancia transversa de la estructura. La capacidad para obtener un control simultáneo de la constante de propagación compleja del modo "leaky", ha sido demostrada mediante el diseño y fabricación de varios tipos de antena "leaky wave" (LWA) y de otros dispositivos como multiplexores y sistemas de enfoque en campo cercano. Para ello, se ha utilizado la tecnología planar de guía de onda integrada en sustrato (susbstrate integrated waveguide, SIW). Esta recientemente desarrollada tecnología, permite diseñar dispositivos de microondas basados en tecnología clásica de guía de ondas con sistemas de fabricación estándar usados en tecnología de circuitos impresos (printed circuit board, PCB). De esta forma, se pueden integrar en un mismo sustrato muchas de las diferentes partes que forman un sistema de comunicaciones, mejorando así su robustez y compactibilidad, además de reducir el coste y de contar con menores pérdidas que otras tecnologías planares como la microstrip. [ENG] The work developed along this doctoral thesis has been focused on the analysis and synthesis of microwave devices in planar technology. In particular, several types of devices based on the radiation mechanism of leaky waves have been studied. Typically, the radiation properties in leaky-wave devices are determined by the complex propagation constant of the leaky mode, wherein the phase constant is responsible for the pointing angle and the leakage rate for the intensity of the radiated fields. In this manner, by controlling both amplitude and phase of the leaky mode, an effective control over the device's radiation diagram can be obtained. Moreover, with the purpose of efficiently obtaining the leaky mode's radiation properties as function of the main geometrical parameters of the structure, several modal tools based on the transverse resonance analysis of the structure have been performed. In order to demonstrate this simultaneous control over the complex propagation constant in planar technology, several types of leaky-wave devices, including antennas (LWAs), multiplexors and near-field focusing systems, have been designed and manufactured in the technology of substrate integrated waveguide (SIW). This recently proposed technology, allows the design of devices based on classical waveguide technology with standard manufacturing techniques used for printed circuit board (PCB) designs. In this way, most of the parts that form a communication system can be integrated into a single substrate, thus reducing its cost and providing a more robust and compact device, which has less losses compared to other planar technologies such as the microstrip.Universidad Politécnica de Cartagen

Passive Planar Microwave Devices

Passive planar circuits play a key role in many RF/microwave applications, such as in wireless communications, medical instrumentation, and remote sensing. From their earliest developments during World War II to the present day, they have become indispensable for their low cost and low weight while maintaining high performance. As a result, they are still undergoing research and development. In recent years, multiple technologies have been proposed with the aim of combining the characteristics of traditional planar and nonplanar transmission lines, highlighting substrate integrated waveguide (SIW) technology as the most popular among them. This Special Issue is focused on highlighting recent contributions to microwave device development in planar technologies. A total of twelve papers have been published in this volume, each addressing several important research problems and advancements in the field of filters, multiport circuits, dividers, combiners, couplers, multiplexers, microwave sensors, and antennas. These articles provide a significant contribution to the state of the art

School refusal profiles maintained by negative reinforcement and their relationship with self-perceived health

Health alterations and school refusal behavior may significantly affect student evolution in all areas of student lives. The objective of this study was to use latent profile analysis to identify school refusal profiles sustained by negative reinforcement and to determine their relationship with distinct self-perceived health variables (Satisfaction, Well-being, Resilience, Performance, and Risk-Taking). The School Refusal Assessment Scale-Revised (SRAS-R) and the Child Health and Illness Profile (CHIP-CE/CRF) were administered to 737 students (60.9% male) aged between 8 and 10 (M = 8.76, SD = 0.74). Three profiles of school refusal maintained by negative reinforcement were obtained: no risk, moderate risk, and high risk. It was confirmed that school refusal through negative reinforcement correlates negatively with health dimensions, also finding that a higher risk profile for school refusal is associated with lower levels of self-perceived health. Similarly, it was determined that the high-risk profile is the most maladaptive, with significantly lower data in four of the five self-perceived health dimensions that were evaluated. In conclusion, remaining in situations with no or moderate risk of school refusal due to negative reinforcement encourages higher levels of self-perceived health, while being at high risk of school refusal due to negative reinforcement is associated with worse self-perceived health.This work has been funded by the Conselleria de Educación, Universidades y Empleo [CIAICO/2022/078]

Mainstreaming graphene in electrochemical energy storage devices: a Delphi-based adaptive priority-setting

Mainstreaming novel materials is essential to overcome crucial limitations of energy storage devices to address societal challenges and decarbonization efforts. However, mainstreaming requires enabling conditions that are influenced by complexities and tensions. Building on the concept of outcome-oriented scaling, this study explores how prioritization of interdependent drivers and barriers influences mainstreaming graphene in electrochemical energy storage devices. We capture the knowledge and perceptions of an expert panel through a Delphi survey combined with in-depth interviews. We find the ongoing prioritization trajectories to fail in setting interdependent drivers and barriers as a vision to achieve impact at scale, in creating opportunities to accelerate mainstreaming, and in addressing key sustainability pressures and reconfiguration barriers. Also, we find widespread consensus that urgent action is required to bend the prioritization trajectories in the right direction to achieve impact at scale. Mainstreaming graphene is likely to challenge, compete and disrupt incumbent systems instead of enabling a smooth transitionThe first author received funding from the Economic Development Agency for La Rioja, under the doctoral fellowship program, grant number: 1168/2018 (Resolución de concesión nº 1168/2018, de la Consejera de Desarrollo Económico e Innovación

Non-uniform sinusoidally modulated half-mode leaky-wave lines for near-field focusing pattern synthesis

A novel non-uniform sinusoidally modulated half-mode microstrip structure with application to near-field focused leaky-wave radiation in the backward Fresnel zone is proposed. First, it is presented a dispersion analysis of the constituent backward leaky wave in the sinusoidally modulated unit cell in half-width microstrip technology. This information is then used to design a finite non-uniform line that focuses the radiated fields at the desired point. Finally, eight similar line sources are arranged in a radial array to generate a three-dimensional focused spot located at the desired focal length over the simple central coaxial feeding. Simulated and experimental results are presented to validate the proposed simple approach.Ministerio de Educación y Ciencia TEC2013-47037-C5-5-R, TEC2010-21520-C04-04, TEC2013-41913-PFundación Séneca 08833/PI/0

Multilayered balanced dual-band bandpass filter based on magnetically coupled open-loop resonators with intrinsic common-mode rejection

A new dual-band balanced bandpass filter based on magnetically coupled open-loop resonators in multilayer technology is proposed in this paper. The lower differential passband, centered at the Global Positioning System (GPS) L1 frequency, 1.575 GHz, was created by means of two coupled resonators etched in the middle layer of the structure, while the upper differential passband, centered at a Wi-Fi frequency of 2.4 GHz, was generated by coupling two resonators on the top layer. Magnetic coupling was used to design both passbands, leading to an intrinsic common-mode rejection of 39 dB within the lower passband and 33 dB within the upper passband. Simulation and measurement results are provided to verify the usefulness of the proposed dual-band differential bandpass filter.Ministerio de Ciencia, Innovación y Universidades TEC2017-84724-

Student engagement in the school : interpersonal and inter-center differences

This research project aim to identify differences in students' engagement in school life, in terms of both sociopersonal characteristics (sex and educational stage) and type of school (state, private with some state funding and cooperative). Participants were 1229 students aged between 9 and 17 (598 from a worker cooperative and 631 from state and private stated-funded schools of the Basque Country and Catalonia). Three components were distinguished in engagement (emotional, behavioural and cognitive) as measured by a Spanish version of the Leadership, Organisational Learning and Student Outcomes (LOLSO) questionnaire by Mulford, Silins and Leithwood (2004). These data are related to the responses given to the Psychological Sense of School Membership (PSSM) questionnaire by Goodenow (1993), which examines factors affecting school engagement, with specific focus on students' sense of belonging. The results indicate that girls' engagement is higher than that of boys; that it decreases as students move up the school; and is higher in the worker cooperative than in the state or private stated-funded schools. Engagement was also found to be related to teachers' work and the relationship between teachers and studentsEsta investigación tiene por objeto identificar diferencias en la implicación del alumnado en su centro escolar tanto en función de características sociopersonales (sexo y ciclo educativo) como de la titularidad del centro (público, concertado, cooperativa). Participan en la misma 1229 estudiantes de entre 9 y 17 años (613 de un colegio cuyo profesorado conforma una cooperativa y 656 de centros públicos y concertados del País Vasco y Cataluña). Se diferencian tres componentes de la implicación (emocional, conductual y cognitiva) medida mediante una versión castellana del cuestionario Leadership, Organizational Learning and Student's Outcomes (LOLSO), de Mulford, Sillins y Leithwood (2004); se relacionan estos datos con las respuestas al cuestionario Psychological Sense of School Membership (PSSM), de Goodenow (1993), que analiza factores que afectan a la implicación escolar y específicamente al sentimiento de pertenencia. Los resultados indican que la implicación de las alumnas en mayor que la de los alumnos, que disminuye según avanza el curso escolar y que en el colegio-cooperativa es superior a la de centros de titularidad pública y concertada. La implicación, por otro lado, guarda relación con el trabajo de los docentes y con las relaciones entre estudiantes y profesores

Control electrónico del haz radiado en antenas leaky wave activas

En el siguiente artículo se presenta una novedosa antena leaky-wave (LWA) activa. La estructura es capaz de reconfigurar electrónicamente su haz de radiación principal trabajando a una frecuencia fija de operación. Dicha propiedad de redireccionamiento electrónico se introduce gracias a la utilización de una superficie de alta impedancia (HIS) activa cargada con diodos varactores. La recorifiguración del haz se basa en el control del desfase introducido por la HIS activa al variar la tensión de polarización aplicada a los diodos. Dicha variación cambia la constante de fase de los modos de fuga (modos leaky) que se propagan a través de la estructura, modificando el ángulo de radiación. La antena se ha analizado mediante un método basado en la Técnica de Resonancia Transversa (TRE), analizando una Red Equivalente Transversa (TEN) de la estructura. Para validar los resultados obtenidos, se han desarrollado y simulado varios diseños trabajando a 5.5GHz.Centro Universitario de la Defensa. Escuela de Turismo de Cartagena. Escuela Técnica Superior de Ingeniería Industrial UPCT. Escuela Técnica Superior de Ingeniería de Telecomunicación (ETSIT). Escuela de Ingeniería de Caminos y Minas (EICM). Escuela de Arquitectura e Ingeniería de Edificación (ARQ&IDE). Parque Tecnológico de Fuente Álamo. Navantia. Campus Mare Nostru

Control de la directividad en broadside en antena leaky-wave 1D

En este artículo se propone un método de diseño para controlar el ancho de haz en una antena leaky-wave ID cargada con una superficie selectiva en frecuencia. En concreto, esta antena posee la ventaja de apuntar en broadside porque está alimentada por el centro.Centro Universitario de la Defensa. Escuela de Turismo de Cartagena. Escuela Técnica Superior de Ingeniería Industrial UPCT. Escuela Técnica Superior de Ingeniería de Telecomunicación (ETSIT). Escuela de Ingeniería de Caminos y Minas (EICM). Escuela de Arquitectura e Ingeniería de Edificación (ARQ&IDE). Parque Tecnológico de Fuente Álamo. Navantia. Campus Mare Nostru