Inhomogeneous contraction of interatomic distances in metallic clusters: Calculations for Csn and OCsn

The equilibrium geometrical structures of Csn and OCsn clusters have been obtained by a method that, in the framework of density-functional theory, describes the ion-electron interaction by means of a pseudopotential that is spherically averaged about the cluster center. In the size range studied (up to n =78 and 70, respectively) the clusters present well-separated atomic layers for which the distances to the two closest neighbors of each atom have been analyzed, showing that there is an inhomogeneous shrinking of the geometrical structure, in the sense that the distances obtained for atoms in the inner layers are lower than those for the outer ones. The analysis of the growing of the clusters suggests that the equilibrium geometries are those for which any atom of the aggregate has its closest neighbor at a distance lower than the nearest-neighbor distance of the pure bulk metal. For small (n ≤ 20) pure clusters, geometries of high symmetry have been found, which are completely modified by the presence of the oxygen impurity. A regular octahedron is formed around the oxygen atom in most cases

Radiation shielding properties of siderurgical aggregate concrete

ABSTRACT: The world is changing, and consequently so are policies on the use of natural resources. One of the most convenient ways to reduce the consumption of natural aggregates in the production of more sustainable construction materials is the use of recovered industrial by-products. In this study, concretes are designed using siderurgical aggregates from electric arc furnaces, taking advantage of their high density to use them as radiation shielding concrete. To verify the suitability of these aggregates, four concrete mixes were designed with different aggregates: limestone, siderurgical magnetite aggregates (the most commonly used in the nuclear field). The comparison of the different mixes was carried out focusing on the physical?mechanical properties in the field of ionizing radiation shielding (gamma radiation and neutron shielding) by means of simulations. In addition, an analysis was performed to establish how the w/c ratio and the amount of CEM affect shielding properties. In terms of linear attenuation coefficient and neutron transmission rate, the concrete with siderurgical aggregates shows intermediate capability in comparison with the limestone aggregate and magnetite concrete. The increase in the amount of cement and the w/c ratio caused a decrease in the linear attenuation coefficient and a reduction in the neutron transmission rate, but the variation in the w/c ratio did not have a significant impact on the neutron transmission rate.This research was co-financed by the European Regional Development Fund (ERDF) and the Ministry of Economy, Industry and Competitiveness (MINECO) within the framework of the project RTC2016-5637-3. The research has been possible thanks to the collaboration of the company INGECID, the department LADICIM (University of Cantabria) the Modern Physics Department of the University of Cantabria and the companies ROCACERO and SIDENOR

Estudio del impacto humano en una Reserva Natural: las Marismas de Santoña (Cantabria, España)

ABSTRACT: The Santoña Marshes Nature Reserve is one of the most important ecosystems of the Spanish Cantabrian coast due to its ecological value as a wintering area for migratory birds. Since an increase in population and substantial changes in the use of land have been observed in this area during the last century, the aim of this work was to attempt to see if anthropogenic activities are recorded in the accumulating sediments. Two sediment cores (50 cm length) were collected for isotopic dating (210Pb and 137Cs) and geochemical study (heavy metals). The data indicate an increasing trend in sedimentation rates during the last century, probably related to the progressive loss of the estuarine domains and the changes in their original hydrodynamic conditions due to infilling and the construction of dykes. However, no significant anthropogenic inputs of heavy metals have been detected in recent times.RESUMEN: La Reserva Natural de las Marismas de Santoña, situada en la costa cantábrica, posee un gran valor ecológico como lugar de invernada de aves migratorias. Dado el importante aumento de la presencia humana en la zona durante el último siglo, este trabajo tiene como objetivo estudiar si estas actividades antrópicas han dejado su huella en los sedimentos acumulados. Para ello se ha abordado la datación isotópica (137Cs y 210Pb) y el estudio geoquímico (metales pesados) de dos sondeos de 50 cm de longitud. Los resultados obtenidos señalan la existencia de un importante incremento en las tasas de sedimentación durante el ultimo siglo, posiblemente relacionado con la pérdida progresiva de la superficie y de las dinámicas estuarinas como consecuencia de los rellenos y de la construcción de diques. Sin embargo, no se han detectado niveles significativos de contaminación en metales pesados en los sedimentos más recientes

Mechanical behavior and microstructural changes in polyurethane exposed to high doses of X rays, gamma rays or neutron irradiation

Polymeric materials are widely used in applications where the environmental conditions entail their exposure to different sources of irradiation (in most cases ultraviolet or low dose of electromagnetic irradiation for sterilization). In contrast, in this study we have assessed the modifications undergone by a series of polyurethane joints exposed to high radioactive doses of either X-rays or gamma rays (with doses of 20.5, 100, 300 and 900?kGy) or neutron irradiation (with a fluence of 7.23·1010 n/cm2) which are typical of the environment of nuclear reactors. Tensile tests were carried out to assess the change in mechanical properties derived from the radioactive exposure. Three mechanical parameters were used to monitor the evolution of strength, ductility and toughness: the tensile strength (?max), the strain corresponding to ?max (??max) and the density of energy absorbed prior to maximum load (U?max). With regards to X and gamma rays, a negative impact of radiation on strength, ductility and toughness was observed. The detailed statistical analysis of the results has shown that a threshold dose of 300?kGy must be overcome to trigger the damage process. For the fluence employed in this study, neutron irradiation produced very little change in the mechanical properties. The SEM fractographic study has allowed the influence of irradiation on the material failure mechanisms to be identified. Thus, the fracture surface of unirradiated samples shows evidence of plastic deformation and ductile tearing. In contrast, the fracture surface of those samples exposed to a dose of 900?kGy corresponds to brittle fracture. In a consistent way, samples exposed to neutron irradiation have a fracture surface similar to that of the non-irradiated material. In summary, electromagnetic radiation for doses above the threshold leads to the embrittlement of polyurethane. Raman spectroscopy was employed to identify the microstructural changes induced by the different sources of radiation at the molecular level. The band corresponding to the vibration of the C-H bending bonds present in the polyurethane was measured as a function of the dose, finding a strong correlation between its vibration frequency and the dose of exposure to electromagnetic radiation. This shift is more sensitive than the mechanical material response since the frequency is affected at doses of 100?kGy, below the threshold previously identified for any of the mechanical properties. This correlation opens the door for the use of Raman spectroscopy as a novel non-destructive tool to characterize the microstructural effect of irradiation on polyurethane

Diseño y elaboración de modelos anatomía normal y patológicos del sistema cardiovascular fetal mediante impresión 3D

Depto. de Salud Pública y Materno - InfantilFac. de MedicinaFALSEsubmitte

Point-of-care manufacturing: a single university hospital's initial experience

The integration of 3D printing technology in hospitals is evolving toward production models such as point-of-care manufacturing. This study aims to present the results of the integration of 3D printing technology in a manufacturing university hospital.Analysis and interpretation of the data supported by Project PI18/01625 (Ministerio de Ciencia, Innovación y Universidades, Instituto de Salud Carlos III) and European Regional Development Fund (“Una manera de hacer Europa”)

Transversalidad y valores

Integra temas transversales como la paz, solidaridad, igualdad, tolerancia, salud, respeto al entorno, consumo y seguridad vial en el proceso de aprendizaje de los jóvenes como componente de su formación cuidadana. Los objetivos son: crear un estado de sensibilidad mayoritario en la comunidad educativa para que esté expectante ante los problemas que requieren su solidaridad; propiciar un intercambio creativo de contenidos conceptuales y procedimentales de temas transversales entre los distintos departamentos; resolver conflictos de convivencia en el centro por medio del diálogo constructivo; fomentar una conciencia de solidaridad, responsabilidad, respeto y afán de superación humana e intelectual y avanzar en la integración del equipo docente, desarrollando un espíritu favorable a la investigación-acción. Realizan actividades en fechas significativas: día mundial contra el sida, de los derechos humanos, sin tabaco y aniversario de la Constitución; visitas al Museo del Prado, Mezquita, Iglesia Evangélica y a la Sinagoga. Destaca la participación en campañas de solidaridad en colaboración con ONGs y la convocatoria de concursos literarios, de carteles y vídeos y excursiones ecológicas. Evalúa el grado de consecución de los objetivos y de participación y debate por medio de la observación, encuestas de opinión y trabajos realizados.Madrid (Comunidad Autónoma). Consejería de Educación y CulturaMadridMadrid (Comunidad Autónoma). Subdirección General de Formación del Profesorado. CRIF Las Acacias; General Ricardos 179 - 28025 Madrid; Tel. + 34915250893ES

Profundización en la sensibilización y formación en la accesibilidad e inclusión de las personas con discapacidad visual al proceso de enseñanza-aprendizaje dentro de la UCM

El presente proyecto, SENSIVISUAL-UCM-II, supone una continuidad en los procesos de formación y sensibili-zación de la comunidad universitaria en el uso de tecnologías de información y comuni-cación, TICs, accesibles para personas con discapacidad visual, donde debe prevalecer el derecho a la atención equitativa y de calidad, permitiendo su plena inclusión educativa y social, mediante el respeto a sus necesidades específicas. El presente proyecto conti-nua con el trabajo realizado y pretende ahondar en la adecuación de contenidos docen-tes mediante el uso de herramientas concretas que mejoren el proceso de enseñanza-aprendizaje para personas con déficit visual, siguiendo con el objetivo de la plena inclu-sión de estos alumnos en el aula. SENSIVISUAL-UCM-II persigue la mejora de la calidad docente y de los servicios vinculados a procesos de innovación en materia de inclusión y diversidad, centrándose en los alumnos con discapacidad visual, y bajo la referencia del Aprendizaje por Servicio. La propuesta educativa de este proyecto combina proce-sos de aprendizaje y de servicio a la comunidad en un mismo proyecto, en el que los compañeros de las personas con discapacidad visual aprenden, generando los materia-les didácticos y potenciando el trabajo colaborativo en los grupos de clase, a la vez que trabajan en necesidades reales de la comunidad con la finalidad de mejorarla. Bajo este objetivo, las acciones llevadas a cabo harán que la comunidad universitaria, tanto profe-sores, alumnos como personal de administración y servicios, se implique en la mejora de la institución en su conjunto y del servicio que ésta ha de dar a la sociedad, consiguiendo colocarnos como universidad de referencia en accesibilidad e inclusión