Pt-impregnated catalysts on powdery SiC and other commercial supports for the combustion of hydrogen under oxidant conditions

We report the study of the catalytic hydrogen combustion over Pt-impregnated powdery silicon carbide (SiC) using H2PtCl6 as precursor. The reaction was conducted in excess of oxygen. β-SiC was selected for the study because of its thermal conductivity, mechanical properties, chemical inertness and surface area. The obtained Pt particles over SiC were medium size (average particle diameter of 5 nm for 0.5 wt% Pt). The activity of the Pt-impregnated catalyst over SiC was compared to those obtained in oxidized form over TiO2 and Al2O3 commercial supports (Pt particles very small in size, average particle diameter of 1 nm for 0.5 wt% Pt in both cases). The case of a SiO2 support was also discussed. Those Pt/SiC particles were the most active because of their higher contribution of surface Pt0, indicating that partially oxidized surfaces have better activity than those totally oxidized in these conditions. SiC was modified with an acid treatment and thus bigger (average particle diameter of 7 nm for 0.5 wt% Pt) and more active Pt particles were obtained. Durability of the SiC and TiO2 supported catalysts was tested upon 5 cycles and both have shown to be durable and even more active than initially. Exposure to the oxidative reaction mixture activates the catalysts and the effect is more pronounced for the completely oxidized particles. This is due to the surface oxygen chemisorption which activates catalystś surface.Junta de Andalucía PE2012-TEP862Ministerio de Economía y Competitividad CTQ2012-32519, CTQ2015-65918-RConsejo Superior de Investigaciones Científicas PIE-201460E01

Reseñas

José VALENZUELA CANDELARIO ; Rosa M. MORENO RODRÍGUEZ ; Fernando GIRÓN IRUESTE, El Hospital Real de Granada y sus Constituciones de gobierno (1593-1857). Asistencia a los pobres y regulación socia

Médicos y cirujanos de Zaragoza en la Edad Moderna : su número y estructura sociofamiliar

A través de la documentación del Colegio de Médicos y Cirujanos de Zaragoza, dispersa en numerosos archivos, se estudia la evolución del número de médicos y cirujanos que hubo en la ciudad de Zaragoza en la Edad Moderna en relación con elnúmero de habitantes que esta ciudad tenía, así como las posibles causas de su aumento o disminución y se comparan sus tasas con las de otras regiones españolas. También, estudiando un censo de 1723, se analizan las estructuras sociofamiliares de las diferentes profesiones sanitarias en Zaragoza, comparándolas con las de otras profesiones, de forma que sea posible conocer los diferentes niveles sociales en los que cada una de ellas estaba, verificándose que el nivel social de los médicos equivalía al de los boticarios, estando por encima del de los cirujanos y albéitares, y por debajo de los profesionales del derecho como notarios, abogados y juristas

Energy efficiency and integration of urban electrical transport systems: EVS and metro-trains of two real European lines

Transport is a main source of pollutants in cities, where air quality is a major concern. New transport technologies, such as electric vehicles, and public transport modalities, such as urban railways, have arisen as solutions to this important problem. One of the main difficulties for the adoption of electric vehicles by consumers is the scarcity of a suitable charging infrastructure. The use of the railway power supplies to charge electric vehicle batteries could facilitate the deployment of charging infrastructure in cities. It would reduce the cost because of the use of an existing installation. Furthermore, electric vehicles can use braking energy from trains that was previously wasted in rheostats. This paper presents the results of a collaboration between research teams from University of Rome Sapienza and Comillas Pontifical University. In this work, two real European cases are studied: an Italian metro line and a Spanish metro line. The energy performance of these metro lines and their capacity to charge electric vehicles have been studied by means of detailed simulation tools. Their results have shown that the use of regenerated energy is 98% for short interval of trains in both cases. However, the use of regenerated energy decreases as the train intervals grow. In a daily operation, an important amount of regenerated energy is wasted in the Italian and Spanish case. Using this energy, a significant number of electric vehicles could be charged every day

El control de las profesiones sanitarias en Aragón : el Prototomedicato y los Colegios

El cargo de Protomédico se implantó en Aragón en 1592, para controlar las profesiones sanitarias en los lugares que no estaban bajo la autoridad de los Colegios. Este articulo examina sus funciones a través de los problemas sanitarios que se plantearon en Aragón en el siglo XVII. Los datos muestran cómo la esfera de intervención de este cargo estaba limitada al examen de médicos, cirujanos y boticarios, y a la inspección de las boticas en los pueblos. Por otra parte, este trabajo destaca cómo los cambios politicos, que se llevaron a cabo por el gobierno central en 1770, y que trasformaron este puesto en una subdelegación del Protomedicato de Castilla, no significaron mucho porque el cargo de Protomédico en Aragón hacía tiempo que había sido servido por sustitutos, y los Colegios siguieron manteniendo su antigua estructura gremial sin perder sus privilegios

Electrocardiographic markers for cognitive decline detection.

Technological and medical advances in recent decades have promoted a lengthening of life expectancy, leading to an increase in age-associated cognitive diseases. As a result, there is a growing interest in efficient and cost-effective technological alternatives for the early detection of cognitive problems. Recent studies show growing evidence of a relationship between electrocardiogram (ECG) parameters and cognitive decline. For this reason, this study aims to assess the validity of ECG markers to detect mild cognitive impairment in elderly subjects. The 'Lemon' database, that contains the cognitive and ECG results of 227 healthy adults, has been analysed. Initially, the electrocardiographic signals have been filtered and adapted to extract multiple relevant ECG markers. To assess the reliability of these markers, several tests were conducted. A statistical analysis between cognitive categories, a machine learning classification problem, and multiple regressions with the additional tests included in the database. The analysis focused on elderly patients, who are classified in three cognitive groups according to their impairment (normal, moderate, and severe). Given the statistical significance between cognitive categories and the favourable results obtained in the regression analysis, two markers should be emphasised: the traditional temporal ratios of heart rate variability (HRV), such as the average beat, a measure of the average between QRS peaks, and the fragmentation ratios (HRF), an estimate of cardiac neuroautonomic dysfunction measured by variations in the QRS interval. Among the different classifiers, the artificial neural network (ANN) stands out, providing the best and most stable classification ratios (55.00 % accuracy, 47.60 % sensitivity, 50.00 % precision, in a three class, five-cross-fold problem). The reported tendency to correctly differentiate normal subjects must be emphasized. This is observed both in the statistical tests, where no significance is found between the moderate and severe groups, and in the classification problems, since there is a bias towards error among subjects with impaired condition. In conclusion, a slight relationship between cardiac markers and cognitive decline has been reported. Further research as well as the replication of the conducted study with different databases is recommended. The idea of combining ECG markers with other literary validated technologies, such as electrocardiography (EEG), suggests an interesting approach that may lead to improved detection of cognitive disorders in early stage

La marca de calidad "CV" para productos agrarios y agroalimentarios

En el presente trabajo realizamos una aproximación a la marca de calidad, como distintivo de identificación que permite diferenciar la oferta comercial de unos productos con una composición genuina, elaborados con unas técnicas que permitan resaltar sus rasgos reconocidos y apreciados, para después hacer referencia a la marca de calidad “CV” para productos agrarios y agroalimentarios y su principal normativa aplicable. En la Comunidad Valenciana, se establece un mecanismo de distinción o diferenciación técnica y comercial de los productos con valores peculiares de tipo cualitativo, sociocultural o económico, para la protección de su singularidad, evitando la competencia desleal y facilitando al consumidor su identificación