Sol–Gel Coordination Chemistry: Building Catalysts from the Bottom-Up

The development of synthetic routes for the tailoring of efficient silica-based heterogeneous catalysts functionalized with coordination complexes or metallic nanoparticles has become a important goal in chemistry. Most of these techniques have been based on postsynthetic treatments of preformed silicas. Nevertheless, there is an emerging approach, so-called sol–gel coordination chemistry, based on co-condensation during the sol–gel preparation of the hybrid material of the corresponding complex or nanoparticle modified with terminal trialkoxysilane groups with a silica source (such as tetraethoxysilane) and in the presence of an adequate surfactant. This method leads to the production of new mesoporous metal complex-silica materials, with the metallic functionality incorporated homogeneously into the structure of the hybrid material, improving the stability of the coordination complex (which is protected by the silica network) and reducing the leaching of the active phase. This technique also offers the actual possibility of functionalizing silica or other metal oxides for a wider range of applications, such as photonics, sensing, and biochemical functions.

Análisis de las relaciones morfología-propiedades en nanocompuestos basados en matrices de copolímeros de bloque

El objetivo principal de la presente investigación ha sido desarrollar una nueva clase de materiales nanocompuestos orgánicos-inorgánicos basados en la capacidad de los copolímeros de bloque de auto-organizarse promoviendo la dispersión de nanopartículas, así como relacionar las diferentes morfologías obtenidas con las propiedades finales de los nanocompuestos. Para generar la nanoestructuración de estos nanocompuestos basados en copolímeros de bloque, como el poli(estireno-b-isopreno-b-estireno) (SIS) y el poli(estireno-b-butadieno-b-estireno) (SBS) en nanopartículas de plata, se han utilizado los conceptos de compatibilización y confinamiento. Es decir, las nanopartículas inorgánicas se confinaron en una sola fase del copolímero de bloque mediante tratamientos superficiales y su funcionalización física. En particular, se utilizaron surfactantes (el cloruro de tetrametilamonio, TMAC, y el dodecanotiol, DT) para favorecer la interacción entre las nanopartículas inorgánicas y la matriz polimérica. Teniendo en cuenta los cálculos teóricos de los parámetros de solubilidad obtenidos mediante la teoría de Hoftizer-Van Krevelen, y la electronegatividad propia de los diferentes elementos, los dos surfactantes elegidos tienen una muy buena compatibilidad con el bloque de estireno favoreciendo la localización de las nanopartículas de plata en este bloque.

Los retos actuales de la Física y Química del color

Día de la Química, Conferencia invitada, San Alberto Magno 2014.

Assessment of Competences in the Physical Chemistry Area: Use of the Department Teaching Portfolio

Competences have become a standard learning outcome in present university education within the European Higher Education Area (EHEA). In this regard, updated tools for their assessment have turned out essential in this new teaching-learning paradigm. Among them, one of the most promising tools is the “learner´s portfolio”, which is based on the gathering and evaluation of a range of evidences from the student, which provides a wider and more realistic view of his/her competence acquisition. Its appropriate use as a formative (continuous) assessment instrument allows a deeper appraisal of student´s learning, provided it does not end up as another summative (final) evaluation tool. In this contribution we propose the use of the portfolio as a unifying assessment tool within a university department (Physical Chemistry), exemplifying how the portfolio could yield both personalized student reports and averaged area reports on competence acquisition. A proposed stepwise protocol is given to organize the individual competence reports and estimate the global competence level following a bottom-up approach (i.e. ranging from the class group, subject, grade, and academic course).

The current challenges of Color Physics and Chemistry

Day of Chemistry, Invited conference, San Alberto Magno 2014

Estrategias territoriales participativas como instrumentos de diagnóstico y prospectiva, en el contexto europeo de los Fondos de Cohesión 2014–2020: el caso de Villena (Alicante)

Las Estrategias Territoriales de carácter participado, se han convertido en el instrumento válido para diagnosticar las necesidades de un territorio. La Unión Europea obliga la aplicación de esta herramienta en el nuevo contexto del periodo 2014–2020. En el municipio de Villena (Alicante), se realizó una estrategia territorial integrada, desde hace dos años que ha derivado en un foro económico social, a través del proceso de abajo-arriba. El estudio de caso avala que la ciudadanía sí que es importante y ha participado activamente en una planificación estratégica ya que los nuevos tiempos, en el contexto del desarrollo local, así lo determinan. Se establecen las fases de aplicación, la metodología utilizada y también los resultados obtenidos.

Shaking-table tests of flat-bottom circular silos containing grain-like material

According to Eurocode 8, the seismic design of flat-bottom circular silos containing grain-like material is based on a rough estimate of the inertial force imposed on the structure by the ensiled content during an earthquake: 80% of the mass of the content multiplied by the peak ground acceleration. A recent analytical consideration of the horizontal shear force mobilised within the ensiled material during an earthquake proposed by some of the authors has resulted in a radically reduced estimate of this load suggesting that, in practice, the effective mass of the content is significantly less than that specified. This paper describes a series of laboratory tests that featured shaking table and a silo model, which were conducted in order to obtain some experimental data to verify the proposed theoretical formulations and to compare with the established code provisions. Several tests have been performed with different heights of ensiled material – about 0.5 mm diameter Ballotini glass – and different magnitudes of grain–wall friction. The results indicate that in all cases, the effective mass is indeed lower than the Eurocode specification, suggesting that the specification is overly conservative, and that the wall–grain friction coefficient strongly affects the overturning moment at the silo base. At peak ground accelerations up to around 0.35 g, the proposed analytical formulation provides an improved estimate of the inertial force imposed on such structures by their contents.