Estudio experimental del Sistema de Albañilería Integral en la construcción de viviendas sismorresistentes. Experimental study of the Integral Masonry System in the construction of earthquake resistant houses

This paper presents the application of the Integral Masonry System (IMS) to the construction of earthquake resistant houses and its experimental study. To verify the security of this new type of building in seismic areas of the third world two prototypes have been tested, one with adobe and the other with hollow brick. In both cases it’s a two-story 6x6x6 m3 house built to scale 1/2. The tests are carried out at the Laboratory of Antiseismic Structures of the Department of Engineering, Pontifical Catholic University of Peru in Lima, in collaboration with the UPM (Technical University of Madrid). This article shows the design process of the prototypes to test, including the sizing of the reinforcements, the characteristics of the tests and the results obtained. These results show that the IMS with adobe or brick remains stable with no significant cracks faced with a severe earthquake, with an estimated acceleration of 1.8 g. Este artículo presenta una aplicación del Sistema de Albañilería Integral (SAI) a la construcción de viviendas sismorresistentes y su estudio experimental. Para verificar su seguridad para su construcción en zonas sísmicas del tercer mundo se han ensayado dos prototipos, uno con adobe, y otro con ladrillo hueco. Se trata de una vivienda de 6x6x6 m3 y dos plantas que se construyen a escala 1/2. Los ensayos se realizaron en el Laboratorio de Estructuras Antisísmicas del Departamento de Ingeniería de la Pontificia Católica Universidad del Perú (PUCP) de Lima en colaboración con la UPM (Universidad Politécnica de Madrid). Este artículo muestra el proceso de diseño de los prototipos a ensayar, incluido el dimensionado de los refuerzos, las características de los ensayos y los resultados obtenidos. Estos resultados muestran que el SAI con adobe o ladrillo permanece estable sin grietas significativas ante un sismo severo, con una aceleración estimada de 1,8 g

Formation of Epitaxial MnBi Layers on (Ga,Mn)As

The initial growth of MnBi on MnAs terminated (GaMn)As is studied by means of synchrotron based photoelectron spectroscopy. From analysis of surface core level shifts we conclude that a continued epitaxial MnBi layer is formed, in which the MnAs/MnBi interface occurs between As and Bi atomic planes. The well defined 1x2 surface reconstruction of the MnAs surface in preserved for up to 2 ML of MnBi before clear surface degradation occurs.Comment: 18 pages, 5 figure

Influence of annealing parameters on the ferromagnetic properties of optimally passivated (Ga,Mn)As epilayers

The influence of annealing parameters - temperature and time - on the magnetic properties of As-capped (Ga,Mn)As epitaxial thin films have been investigated. The dependence of the transition temperature (Tc) on annealing time marks out two regions. The Tc peak behavior, characteristic of the first region, is more pronounced for thick samples, while for the second (`saturated') region the effect of the annealing time is more pronounced for thin samples. A right choice of the passivation medium, growth conditions along with optimal annealing parameters routinely yield Tc-values of ~ 150 K and above, regardless of the thickness of the epilayers.Comment: 5 pages, 3 figure

Post-growth annealing of GaMnAs under As capping - an alternative way to increase Tc

We demonstrate that in situ post-growth annealing of GaMnAs layers under As capping is adequate for achieving high Curie temperatures (Tc) in a similar way as ex situ annealing in air or in N2 atmosphere practiced earlier.Comment: 13 pages, 4 figure

MnAs dots grown on GaN(0001)-(1x1) surface

MnAs has been grown by means of MBE on the GaN(0001)-(1x1) surface. Two options of initiating the crystal growth were applied: (a) a regular MBE procedure (manganese and arsenic were delivered simultaneously) and (b) subsequent deposition of manganese and arsenic layers. It was shown that spontaneous formation of MnAs dots with the surface density of 1$\cdot 10^{11}$ cm$^{-2}$ and $2.5\cdot 10^{11}$ cm$^{-2}$, respectively (as observed by AFM), occurred for the layer thickness higher than 5 ML. Electronic structure of the MnAs/GaN systems was studied by resonant photoemission spectroscopy. That led to determination of the Mn 3d - related contribution to the total density of states (DOS) distribution of MnAs. It has been proven that the electronic structures of the MnAs dots grown by the two procedures differ markedly. One corresponds to metallic, ferromagnetic NiAs-type MnAs, the other is similar to that reported for half-metallic zinc-blende MnAs. Both system behave superparamagnetically (as revealed by magnetization measurements), but with both the blocking temperatures and the intra-dot Curie temperatures substantially different. The intra-dot Curie temperature is about 260 K for the former system while markedly higher than room temperature for the latter one. Relations between growth process, electronic structure and other properties of the studied systems are discussed. Possible mechanisms of half-metallic MnAs formation on GaN are considered.Comment: 20+ pages, 8 figure

Graphene as Metal-Free Catalyst for Aqueous Phase Reforming of Ethylene Glycol

[EN] Graphene obtained by pyrolysis of alginate shows in the absence of any metal, catalytic activity towards the decomposition of ethylene glycol into hydrogen and carbon dioxide at 250 8C due to the presence of hydrogenating/dehydrogenating sites. This reaction has interest in the context of valorization of waste waters from cellulose depolymerization and it is typically catalyzed by platinum and other transition metals. In this regard, the use of graphene as metal-free catalyst may have a considerable advantage from the point of sustainability of the catalyst. Based on the influence of the presence of acids and bases and the lack of influence of quenchers of reactive oxygen species, it is proposed that the active sites on the graphene could be frustrated acid-base Lewis pairs acting as dehydrogenating centers. Controls with oxalic acid and glyoxal have shown that if ethylene glycol is converted into these a-dicarbonylic compounds, spontaneous decarboxylation would occur totally (oxalic acid) or in some extent (glyoxal. 30%). In the last case, decarboxylation is also assisted by graphene.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa and CTQ2015-69153-CO2-R1) and Generalitat Valenciana (Prometeo 2013-014) is gratefully acknowledged. I. E.-A. thank to Spanish Ministry of Science for PhD scholarships. This research is partly funded by the EU-JSPS joint initiative through the NOVACAM project.Esteve-Adell, I.; Bakker, N.; Primo Arnau, AM.; Hensen, EJM.; García Gómez, H. (2017). Graphene as Metal-Free Catalyst for Aqueous Phase Reforming of Ethylene Glycol. ChemistrySelect. 2(22):6338-6343. https://doi.org/10.1002/slct.201701138S6338634322

Ensayos de dinteles de fábrica de ladrillo atirantada sobre los nuevos Apoyos Pi, distanciados 6m entre sí

Comunicación presentada en las II Jornadas de Investigación en Construcción: "60 años de Informes de la Construcción", celebradas los pasados 22, 23 y 24 de mayo de 2008 en el Instituto "Eduardo Torroja" de Ciencias de la Construcción (IETCC-CSIC) de Madrid.Comparando la Arquitectura de Ladrillos del s.XIX con el empleo del ladrillo en la Arquitectura del s.XX, se puede observar que abunda mayor patología en las fábricas de ladrillo cara vista recientes que en las más antiguas. El primer paso para prevenir la abundante fisuración de la albañilería apreciada en España a finales del siglo pasado, se dio en 1992, con la realización del "Manual Murfor: La fábrica armada", estableciéndose en él los criterios posteriormente contemplados en el "Eurocódigo 6: Estructuras de Fábrica", de recomendar armar con el 0,03% de la sección del muro, y a distancias verticales no mayores de 600mm. Las primeras aplicaciones arquitectónicas de la fábrica armada en España, fueron realizadas por este Arquitecto en sus obras de la Plaza de la Remonta y de El Espinillo, divulgándose por su potencial arquitectónico, tanto en Europa como en América.En este artículo se retoman las posibilidades del incremento de prestaciones de la fábrica armada Murfor con "arcos atirantados ciegos de gran luz", establecidas por primera vez en el Manual español, lo que permite salvar 6m de luz con solamente 2 armaduras Murfor de 5mm de diámetro en la parte inferior de los dinteles.Los autores agradecen la inestimable colaboración de los Institutos de Investigación IBAC de Aachen (Alemania) y el I.E. Torroja de Madrid (España), por haber hecho posible esta interesante colaboración investigadora europea de valor internacional.Peer reviewe