Macros

Funciones con un número variable de argumentos. Formas especiales quote y quasiquote. Macros en Scheme. Ejemplos

Unravelling the optimization of few-layer graphene crystallinity and electrical conductivity in ceramic composites by Raman spectroscopy

Zirconia composites with few-layer graphene (FLG) were prepared by two powder processing routines -ultrasonic agitation or planetary ball milling- and spark plasma sintered at 1250 and 1300 °C. An in-depth study of the crystallinity of FLG, in terms of presence and nature of defects, was performed by Raman spectroscopy, revealing enhanced FLG crystallinity after sintering. This enhancement was more noticeable in the composites sintered at the highest temperature, with lower amount of structural defects and amorphous carbon. However, remaining amorphous carbon was detected in the composites prepared by planetary ball milling even after sintering at the highest temperature, resulting in lower electrical conductivities. Optimum results in terms of electrical conductivity were achieved for the composites prepared by ultrasonic agitation and sintered at 1300 °C, with electrical percolation limit below 2.5 vol% FLG and high electrical conductivity (678 S/m for 5 vol% FLG), as result of the enhanced FLG crystallinity after sintering.Ministerio de Ciencia, Innovación y Universidades PGC 2018- 101377-B-100Ministerio de Asuntos Económicos y Transformación Digital BES-2016- 078711Universidad de Sevilla USE-18740-

La ciudad amable: propuesta de evaluación transversal

El programa de La Ciudad Amable -LCA- creado en 2013 por la Consejería de Fomento y Vivienda de la Junta de Andalucía, dirigido a los Ayuntamientos, orienta las actuaciones en el espacio público andaluz hacia metodologías de intervención que incorporen parámetros de activación urbana, movilidad sostenible, calidad ambiental, participación o integración social. LCA se desarrolla en tres fases: formativa; de creación -poniendo en práctica estos principios en el espacio urbano-; y divulgativa. La calidad de la propuesta la ha hecho merecedora de ser seleccionada en el Concurso de Buenas Prácticas de Dubai 2014, siendo Finalistas en la categoría Best. El proyecto de investigación “Sistema de información activa de los espacios públicos de Andalucía” (GGI3001/IDIU) incluye como parte de su investigación el análisis de los 21 proyectos licitados en la primera convocatoria LCA 2013, determinando la integralidad de las propuestas y la definición de espacios públicos sostenibles e inclusivos.La Ciudad Amable Programme -LCA- created in 2013 by the Department of Development and Housing of the Regional Government of Andalusia, and aimed at the local councils, guides the interventions within Andalusian public spaces towards methodologies in which parameters of urban activation, sustainable mobility, environmental quality, participation and social integration are brought together. LCA is developed in three phases: training; creation- putting in practice the objetives of this Programme in the urban space-; and dissemination. Due to its quality, this initiative was selected, and then competed in 2014 for the Dubai International Award for Best Practices, and was finalists for the -Best- category. As part of the research project, “An active information system on the public spaces of Andalusia” (Code: GGI3001/IDIU), it has been evaluated the 21 projects put forward for the first call in 2013. The study of the projects has allowed us to determine the scope of their contribution to the definition of sustainable and inclusive public spaces

Graphene nanoplatelets for electrically conductive 3YTZP composites densified by pressureless sintering

3 mol% yttria tetragonal zirconia polycrystalline (3YTZP) ceramic composites with 2.5, 5 and 10 vol% graphene nanoplatelets (GNP) were pressureless sintered in argon atmosphere between 1350 and 1450 °C. The effects of the GNP content and the sintering temperature on the densification, microstructure and electrical properties of the composites were investigated. An isotropic distribution of GNP surrounding ceramic regions was exhibited regardless the GNP content and sintering temperature used. Electrical conductivity values comparable to the ones of fully dense composites prepared by more complex techniques were obtained, even though full densification was not achieved. While the composite with 5 vol% GNP exhibited electrical anisotropy with a semiconductor-type behaviour, the composite with 10 vol% GNP showed an electrically isotropic metallic-type behaviour.Ministerio de Economía y Competitividad MAT2015-67889-

Uso de Apache Forrest y CVS para la actualización y generación de material docente de una asignatura

En este artículo se detalla un procedimiento que se ha llevado a cabo en la asignatura Lenguajes y Paradigmas de Programación para la gestión de la web (actualización y generación) por un grupo de profesores. El enfoque está basado en la utilización de distintas herramientas de libre distribución. Se ha conseguido una gestión estructurada y accesible por todos los profesores de la asignatura. Por otra parte, el uso de dichas herramientas ha facilitado la generación del contenido de la asignatura en distintos formatos

Eficacia en la aplicación de las medidas de formación para los deportistas de alto nivel en el territorio español

Academic training and planning are fundamental in ensuring the integration of elite athletes into the labour market. The main goal of this study was to analyse the extent to which academic measures are applied by the system's different stakeholders. When the information process was analysed, certain shortcomings were noted. Most calls by athletes were for the dates of exams to be changed due to their coincidence with an official competition, as confirmed by requests to all bodies. The period from 20 to 30 years of age is critical in academic terms and a fully comprehensive service should be ensured for these top athletes in order to provide ongoing guidance.La formación académica y la planificación son fundamentales para una exitosa inserción laboral de los atletas de élite. El objetivo de este estudio fue detectar el nivel de aplicación de las medidas de formación por los diferentes agentes que participan en el sistema. Al analizar el proceso de información se apreciaron ciertas carencias en el mismo. El cambio de fechas de exámenes con motivo de competiciones/concentraciones oficiales fue el aspecto más demandado por los diferentes deportistas. Dado que el periodo de los 20 a los 30 años es crítico para la formación, sería necesario aportar un servicio de cobertura total para la población de deportistas de Alto Nivel, con el fin de dar un asesoramiento permanente y trazar una línea continua desde la vida deportiva a la vida laboral en los deportistas.A formação académica e a planificação são fundamentais para uma bem sucedida inserção laboral dos atletas de elite. O objectivo deste estudo foi detectar o nível de aplicação de medidas de formação pelos diferentes agentes desportivos que participam no sistema. Ao analisar o processo de informação foram identificadas algumas carências no mesmo. A mudança das datas dos exames por motivos de competições/concentrações oficiais foi o aspecto mais pedido pelos diferentes desportistas. Dado que o período dos 20 aos 30 anos é crítico para a formação, seria necessário adicionar um serviço de cobertura total para a população de desportistas de Alto Rendimento, com o objectivo de assessorar permanentemente e traçar uma linha contínua desde a vida desportiva à vida laboral dos desportistas

Eficacia en la aplicación de las medidas de formación para los deportistas de alto nivel en el territorio español

La formación académica y la planificación son fundamentales para una exitosa inserción laboral de los atletas de élite. El objetivo de este estudio fue detectar el nivel de aplicación de las medidas de formación por los diferentes agentes que participan en el sistema. Al analizar el proceso de información se apreciaron ciertas carencias en el mismo. El cambio de fechas de exámenes con motivo de competiciones/concentraciones oficiales fue el aspecto más demandado por los diferentes deportistas. Dado que el periodo de los 20 a los 30 años es crítico para la formación, sería necesario aportar un servicio de cobertura total para la población de deportistas de Alto Nivel, con el fin de dar un asesoramiento permanente y trazar una línea continua desde la vida deportiva a la vida laboral en los deportistas

Microstructure, interfaces and properties of 3YTZP ceramic composites with 10 and 20 vol% different graphene-based nanostructures as fillers

The graphene family comprises not only single layer graphene but also graphene-based nanomaterials (GBN), with remarkably different number of layers, lateral dimension and price. In this work, two of these GBN, namely graphene nanoplatelets (GNP) with n∼15–30 layers and few-layer graphene (FLG) with n < 3 layers have been evaluated as fillers in 3 mol% yttria stabilized tetragonal zirconia (3YTZP) ceramic composites. Composites with 10 and 20 vol% GNP or FLG have been fabricated by wet powder processing and spark plasma sintering (SPS) and the influence of the content and number of layers of the graphene-based filler has been assessed. For both graphene-based fillers, an intermediate zirconia oxycarbide has been detected in the grain boundaries. The lower stacking degree and much more homogeneous distribution of the FLG, revealed by transmission electron microscopy (TEM), can improve load transfer between the GBNs and the ceramic matrix. However, high FLG contents lower densification of the composites, due partly to the larger FLG interplanar spacing also estimated by TEM. The hardness (both Vickers and nanoindentation) and the elastic modulus decrease with increased GBN content and with improved graphene dispersion. The FLG greatly inhibit the crack propagation that occur perpendicular to their preferential orientation plane. The composites with thinner FLG have higher electrical conductivity than those with GNP. The highest electrical conductivity is achieved by composites with 20 vol% FLG in the direction perpendicular to the compression axis during sintering, σ⊥ = 3400 ± 500 Sm-1.Ministerio de Economía y Competitividad MAT2015-67889-

Spark Plasma Sintered Zirconia Ceramic Composites with Graphene-Based Nanostructures

The addition of graphene-based nanostructures (GBNs) can improve the inherent fragility of ceramics and provide them with improved electrical and thermal conductivities. However, both the starting material (ceramic matrix and GBNs) and the processing/sintering approach are crucial for the final composite microstructure and properties. This work focuses on the influence of the content and dimensions of the GBN filler (10 and 20 vol%; 3 and ~150 layers), the powder-processing conditions (dry versus wet), and the homogenization method (ultrasound sonication versus high-energy planetary ball milling) on GBN/tetragonal zirconia (3YTZP) composites. The microstructure and electrical properties of the spark plasma sintered (SPS) composites were quantified and analyzed. The highest microstructural homogeneity with an isotropic microstructure was achieved by composites prepared with thicker GBNs milled in dry conditions. A high content (20 vol%) of few-layered graphene as a filler maximizes the electrical conductivity of the composites, although it hinders their densification.Ministerio de Economía y Competitividad MAT2015-67889-P

Optimizing the homogenization technique for graphene nanoplatelet/yttria tetragonal zirconia composites: Influence on the microstructure and the electrical conductivity

3 mol% yttria tetragonal zirconia polycrystalline (3YTZP) ceramic composite powders with 10 vol% nominal content of graphene nanoplatelets (GNPs) were prepared using four different homogenization routines: dispersion of the powder mixture by ultrasonication in isopropyl alcohol, homogenization in a high-energy planetary ball mill in wet or dry conditions after ultrasonication, and milling of the powders in a high-energy planetary ball mill in dry conditions. A significant effect of the homogenization routine on the powders particle size distribution was revealed by laser granulometry and Raman spectroscopy. Highly densified composites were obtained after spark plasma sintering (SPS) and remarkable differences on the GNP size, shape and distribution throughout the ceramic matrix and also in the electrical conductivity were observed in the four different composites. The composite with the best performance in terms of electrical conductivity was the one prepared after planetary ball milling of the powders in dry conditions as a consequence of the reduced dimensions of the GNPs and their excellent distribution throughout the ceramic matrix.Ministerio de Economía y Competitividad MAT2015-67889-