Titanato de circonio: estabilidad termodinámica y expansión térmica

El titanato de circonio es un compuesto muy usado en aplicaciones electrocerámicas, aunque también se han descrito aplicaciones en el campo de la catálisis y de los sensores. Dada la anisotropía en la expansión térmica cristalográfica de este compuesto, podría ser planteado como constituyente de componentes estructurales. En general, para asegurar la integridad estructural y la homogeneidad microestructural de una pieza cerámica, es preciso utilizar velocidades de enfriamiento desde la temperatura de fabricación relativamente bajas. Este requerimiento tiene una importancia fundamental en el titanato de circonio, ya que pequeñas variaciones en la composición y en la velocidad de enfriamiento, producen variaciones significativas tanto en la distribución de fases como en la expansión térmica. En este trabajo se revisan los trabajos existentes sobre la estabilidad del titanato de circonio dentro de los sistemas ZrO2-TiO2 y ZrO2-TiO2-Y2O3. Se describen las principales discrepancias acerca de las fases compatibles existentes en la bibliografía actual y se discute el posible origen de estas discrepancias. Asimismo, se revisan los datos existentes sobre la expansión térmica cristalográfica de este compuesto.Peer reviewe

Nou projecte sobre radiacions evolutives alpines a Àsia

Noticia publicada en la web institutcional del Instituto Botánico de Barcelona el 27 de julio de 2016 -- Disponibles PDFs en español y catalán y capturas de pantalla de la noticia en la web.Peer reviewe

Serially improved GTOs for molecular applications (SIGMA): Basis sets from H to Ne

A new approach for generating Gaussian basis sets is reported and tested for atoms from H to Ne. The basis sets thus calculated, named SIGMA basis sets, range from DZ to QZ sizes and have the same composition per shell as Dunning basis sets but with different treatment of the contractions. The standard SIGMA basis sets and their augmented versions have proven to be very suitable for providing good results in atomic and molecular calculations. The performance of the new basis sets is analyzed in terms of total, correlation, and atomization energies, equilibrium distances, and vibrational frequencies in several molecules, and the results are compared at several computational levels with those obtained with the corresponding Dunning and other basis set

“Education Network” a new way to teach Chemistry

The complexity of chemistry has implications for the teaching of chemistry. That chemistry is a very complex subject. The majority of the students at University think that chemistry is a difficult discipline and they have difficulty in understanding the concepts. Moreover, students' interest in chemistry decreases the first year at university. The reason for this decrease might be that the contents of chemistry laboratory classes are boring, out of date and lacking of dynamism that students experience through visual media tools. For these reasons, new programs and methodologies should be developed. Those are based on making chemistry relevant through problem solving and collaborative learning hold promise for reforming chemistry education. It is about an education according to circumstances, which is adapted to context and virtual behaviour of people. It's time to CRUSH boredom by transforming your classroom into an Escape Room adventure. School-based escape games are a great teaching tool. The students while playing, learn. The most important point is that they won’t realize they’re doing both at the same time. In this work, an educational gamification experience based on the escape room concept was developed. The first (Do It Yourself) DIY Escape Room was built the year before at Mechanical Engineer Degree started, that took more than three weeks of work. It was presented to other professors to the same subject at different degrees. That DIY Escape Room was modified and adapted to each group. Each professor changed the clues, problems and so on in order to orientate the topic as much as possible to their students.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Realidad aumentada y proyectos de trabajo. Un maridaje con proyección.

¿Cómo será la sociedad en la que los niños y niñas de infantil de esta segunda década del siglo XXI se desarrollarán como ciudadanos y como profesionales? ¿Qué contentos, necesidades, aprendizajes y estrategias necesitarán para desenvolverse en su ámbito personal y laboral? Esta experiencia realizada en un grupo de 5 años de infantil y monitorizada por estudiantes del Grado en Educación Infantil con la mención de TIC es una apuesta por situar la importancia de las Tecnologías de la Información y la Comunicación para la formación de los futuros profesionales. En concreto, trata sobre la utilización de la realidad aumentada a través de la metodología de proyectos y su incidencia en el aprendizaje en los niños y niñas de educación infantil

The challenge of ab initio calculations in small neon clusters

Weakly bound neon dimer, trimer and tetramers are studied at HF and CCSD(T) levels using Dunning, ANO and SIGMA-s basis sets. Their ground-state binding energies are studied along with some structural properties. SIGMA-s basis sets have been developed explicitly for this issue but in a manner that can be readily applied to other atoms for the study of larger weakly bound systems. The difficulties for attaining accurate results on these systems are assessed by the computation of total, atomization and correlation energies, as well as equilibrium distances, with several basis sets of increasing size, ranging from non-augmented to double-augmented versions. Extrapolations are proposed to predict stabilization energies and the results are compared with previously published dat

Secondary poisoning of non-target animals in an Ornithological Zoo in Galicia (NW Spain) with anticoagulant rodenticides: a case report

The use of anticoagulants has increased in recent times as a method for controlling rodent populations. However, this increased use also provokes accidental and intentional ingestion for both animals and humans, triggering poisoning of non-target organisms. In the present report, a clinical case of secondary-poisoning of birds with anticoagulant rodenticides, which took place after a general rodenticide treatment in an Ornithological Zoological Park, is described. Three birds died as a result and samples were submitted to the Veterinary Hospital in Lugo (Galicia, NW Spain). After necropsy, samples of the birds, together with molluscs and faeces, were submitted to the Toxicology Unit of Caceres (Extremadura, W Spain) in order to detect possible chemicals. Results from HPLC analyses revealed the presence of the rodenticides difenacoum and brodifacoum. The present report shows that the risk of secondary exposure resulting from the scavenging of molluscs is likely to be significant. The potential routes of uptake by invertebrates include the consumption of rodent faeces, rodent carcases, the ingestion of soil-bound residues, and the direct consumption of poison baits.Irene de la Casa-Resino was supported by fellowship PRE09001 from Department of Employment, Enterprise and Innovation (Gobierno de Extremadura, Spain)S

An Embedded System in Smart Inverters for Power Quality and Safety Functionality

The electricity sector is undergoing an evolution that demands the development of a network model with a high level of intelligence, known as a Smart Grid. One of the factors accelerating these changes is the development and implementation of renewable energy. In particular, increased photovoltaic generation can affect the network’s stability. One line of action is to provide inverters with a management capacity that enables them to act upon the grid in order to compensate for these problems. This paper describes the design and development of a prototype embedded system able to integrate with a photovoltaic inverter and provide it with multifunctional ability in order to analyze power quality and operate with protection. The most important subsystems of this prototype are described, indicating their operating fundamentals. This prototype has been tested with class A protocols according to IEC 61000-4-30 and IEC 62586-2. Tests have also been carried out to validate the response time in generating orders and alarm signals for protections. The highlights of these experimental results are discussed. Some descriptive aspects of the integration of the prototype in an experimental smart inverter are also commented upon