Aumento de la tenacidad de hormigones autocompactables reforzados con fibras cortas de polipropileno

Increases in bending tests by the addition of low volume fractions of Polypropylene (PP) Short Fibers PP. These toughness increases are similar to those attained by Fiber Reinforced Concrete (FRC) referred elsewhere as Engineered Cementitious Composites (ECC), having some ductility and strain hardening in direct tensile and flexural tests. Concretes mixtures were manufactured using natural pozzolanic blended Portland cement, volcanic crushed coarse aggregates and fine sand from Sahara desert dunes (0-1 mm) from Canary Islands quarries and sand reservoirs, respectively, besides ordinary siliceous sand (0-4 mm) and fly ash from an anthracite-coal heat generator.Se presentan en este artículo hormigones autocompactables que, mediante la adición de pequeñas fracciones volumétricas de fibras cortas de polipropileno, consiguen incrementos importantes de tenacidad en su comportamiento mecánico a flexión. Estos aumentos de tenacidad son semejantes a los que presentan un grupo de hormigones reforzados con fibras, denominados ECC (Engineered Cementitious Composites), que muestran también alguna ductilidad y endurecimiento por deformación en ensayos de tracción directa y flexión. Los hormigones se dosificaron empleando cemento Pórtland con Puzolana natural, áridos volcánicos de machaqueo y arena fina procedente de dunas del desierto del Sáhara (0-1 mm), de canteras y depósitos de Las Palmas de Gran Canaria (Islas Canarias), respectivamente, además de arena silícea ordinaria (0-4 mm) y cenizas volantes de una central térmica de combustible antracita

Improved O2-assisted styrene synthesis by double-function purification of SWCNT catalyst

The catalytic performance of SWCNT was notably improved in the oxidative dehydrogenation of ethylbenzene (EB) to styrene (ST) upon a double-function purification in one step of the raw SWCNT. This consists of lowering the MeOx concentration and generating surface C=O groups after processing it in nitric acid at controlled conditions, while preserving the structure. The textural improvement was ascribed to the cutting of the tubes/bundles by oxidation and to MeOx removal itself (dilution effect). Both EB conversion and ST selectivity increased with a parallel lowering of the undesired COx selectivity. The conversion was interpreted by the enhancement of the intrinsic properties (i.e., more surface ketonic groups) but also to the higher load of SWCNT in the bed upon purification; both factors contribute to a higher number of active sites (C=O) in the bed for styrene formation. The most purified catalyst underperformed in conversion once the purification altered the SWCNT structure notably. Thus, preserving the structure is an important condition to achieve high conversion and yield. The better selectivity was explained in two ways; more styrene-forming sites (C=O) or less COx-forming sites (uncoated MeOx) in the bed, or both. The styrene yield per catalyst volume was improved by an average of ca. 240 % in comparison to the non-purified SWCNT. Deactivation is critical in maximizing the purification effect on the intrinsic and volumetric yields. In practical terms, the purification method proved to enhance the reaction; the selectivity towards the unwanted COx was significantly lowered with a gain towards styrene, achieving comparable selectivity values as in the conventional process, but operated at much lower temperature

Longtime behavior of nonlocal Cahn-Hilliard equations

Here we consider the nonlocal Cahn-Hilliard equation with constant mobility in a bounded domain. We prove that the associated dynamical system has an exponential attractor, provided that the potential is regular. In order to do that a crucial step is showing the eventual boundedness of the order parameter uniformly with respect to the initial datum. This is obtained through an Alikakos-Moser type argument. We establish a similar result for the viscous nonlocal Cahn-Hilliard equation with singular (e.g., logarithmic) potential. In this case the validity of the so-called separation property is crucial. We also discuss the convergence of a solution to a single stationary state. The separation property in the nonviscous case is known to hold when the mobility degenerates at the pure phases in a proper way and the potential is of logarithmic type. Thus, the existence of an exponential attractor can be proven in this case as well

Bibliografía

Se reseñan los siguientes libros y revistas: * Hombres é ideas educadores, por el doctor Joaquín V. González * Principios de Psicología Biológica, por el doctor José Ingenieros; págs. 471, de la Biblioteca Científico-Filosófica, editada por la casa de Daniel Jorro, Madrid. * Fernando en el Colegio, educación moral y cívica, por el doctor Rodolfo Rivarola; pág. 220. * Trabajos prácticos en Física, por el doctor Teófilo Isnardi; pág. 242; Cabaut y Cía. editores. * Higiene escolar y puericultura. (Memoria correspondiente á los ejercicios 1910-1911, volumen III, de la Dirección General de Escuelas de la Provincia), págs. 568 en 4° mayor. * Fundamentos de la teoría del conocimiento, por F. E. Otto Schultze.-—140 págs * Las Escuelas Populares nocturnas de «puertas abiertas», para adultos. — Dirección General de Escuelas de la Provincia de Buenos Aires. * Campaña antipalúdica. — «La acción profiláctica concurrente de la ingeniería sanitaria» por el ingeniero Antonio Restagno. * Organización y metodología de la Enseñanza Agrícola Extensiva por Hugo Miatello. * Le gout et l’odorat, por Larguier des Bancels. * A text book of experimental Psychology, por Ch. Myers. * L’activité mentale et les éléments de l’esprit, por Fr. Paulhan. 2a edición París, Alean, 1913. * L’année psichologique. — L. Des Bancels é Th. Simón. París, Masson, 1912. * Examinandos y examinadores, crítica á la manera cómo se juzga y cómo debe juzgarse la competencia de los alumnos, por Desiderio Davel. * Biometría, por Manuel Velázquez Andrade, de Méjico; en un folleto de 18 páginas. * Gobierno Escolar en la Provincia de Buenos Aires, puntos de mira, por Rafael Alberto Palomeque; un volumen de 261 págs., editado por A. de Martino, Buenos Aires. * Introducción al estudio de los Miriópodos, por Carlos E. Porter, 1911. — Santiago de Chile, Imprenta Universitaria. Páginas 68. * Trabajos Prácticos para los cursos de Fisiología Vegetal, por el doctor Hans Seckt, catedrático de Botánica en el Instituto nacional del profesorado secundario; págs. 310, con 171 grabados. * Datos sobre la solubilidad de los metales en agua y en líquidos salinos, págs. 138, con numerosos cuadros gráficos y dos láminas. * Congreso Nacional de Enseñanza Secundaria, Nos. 1, 2, 3 y 4. * Psicología pedagógica per la divulgazione dei metodi e di una chiara visione dei problemi e dei resultati delta psicología pedagógica, por José Ferretti. Rivista di PsicologíaFacultad de Ciencias Jurídicas y Sociale

Magma emission rates fromshallow submarine eruptions using airborne thermal imaging

The effusion rate is the most important parameter to gatherwhen a volcanic eruption occurs, because it controls the way inwhich a lava body grows, extends and expands, influencing its dimensional properties. Calculation of lava flow volume from thermal images collected by helicopter surveys has been largely used during the last decade for monitoring subaerial effusive eruptions. However, due to the depths where volcanic activity occurs, monitoring submarine volcanic eruptions is a very difficult task. The 2011–2012 submarine volcanic eruption at El Hierro, Canary Islands, has provided a unique and excellent opportunity to monitor eruptive processes occurring on the seabed. The use of a hand-held thermal camera during daily helicopter flights allowed us to estimate for the first time the daily and total erupted magma volumes from a submarine eruption. The volume of magma emitted during this eruption has been estimated at 300 Mm3, giving an average effusion rate of ~25 m3 s−1. Thermal imagery by helicopter proved to be a fast, inexpensive, safe and reliable technique of monitoring volcanic eruptions when they occur on the shallow seabed.This research was financially supported by the projects MAKAVOL (MAC/3/C161) from the European Union MAC 2007–2013 Transnational Cooperation Program as well as from the Cabildo Insular de Tenerife. We are also grateful to the staff of El Hierro airport (AENA) for providing logistical support.Published219-2255V. Sorveglianza vulcanica ed emergenzeJCR Journalrestricte

Analysis of end-to-end multi-domain management and orchestration frameworks for software defined infrastructures: An architectural survey

Over the last couple of years, industry operators' associations issued requirements towards an end-to-end management and orchestration plane for 5G networks. Consequently, standard organisations started their activities in this domain. This article provides an analysis and an architectural survey of these initiatives and of the main requirements, proposes descriptions for the key concepts of domain, resource and service slicing, end-to-end orchestration and a reference architecture for the end-to-end orchestration plane. Then, a set of currently available or under development domain orchestration frameworks are mapped to this reference architecture. These frameworks, meant to provide coordination and automated management of cloud and networking resources, network functions and services, fulfil multi-domain (i.e. multi-technology and multi-operator) orchestration requirements, thus enabling the realisation of an end-to-end orchestration plane. Finally, based on the analysis of existing single-domain and multi-domain orchestration components and requirements, this paper presents a functional architecture for the end-to-end management and orchestration plane, paving the way to its full realisatio

Analysis of end-to-end multi-domain management and orchestration frameworks for software defined infrastructures: An architectural survey

Over the last couple of years, industry operators' associations issued requirements towards an end-to-end management and orchestration plane for 5G networks. Consequently, standard organisations started their activities in this domain. This article provides an analysis and an architectural survey of these initiatives and of the main requirements, proposes descriptions for the key concepts of domain, resource and service slicing, end-to-end orchestration and a reference architecture for the end-to-end orchestration plane. Then, a set of currently available or under development domain orchestration frameworks are mapped to this reference architecture. These frameworks, meant to provide coordination and automated management of cloud and networking resources, network functions and services, fulfil multi-domain (i.e. multi-technology and multi-operator) orchestration requirements, thus enabling the realisation of an end-to-end orchestration plane. Finally, based on the analysis of existing single-domain and multi-domain orchestration components and requirements, this paper presents a functional architecture for the end-to-end management and orchestration plane, paving the way to its full realisation

Emisiones naturales de CO2 y otros volátiles asociadas a la actividad volcánica en las Islas Canarias

Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna

Evaluación de las emisiones de SO2 a la atmósfera procedentes de las centrales térmicas y refinería de petróleo en la Isla de Tenerife mediante el uso de COSPEC

Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna)Las emisiones de S02 y NOx tiene efectos directos e indirectos muy significativos sobre el medio ambiente. El COSPEC es una técnica de espectroscopia ultravioleta que proporciona la posibilidad monitorizar de forma remota los niveles de emisión de S02 procedente de una zona industrial. Durante agosto y septiembre de 2003 se han realizado 217 medidas remotas para evaluar la emisión de S02 procedentes de las Centrales Térmicas de Caletil/as y Granadilla así como de la Refinería de Petróleo en SIC de Tenerife mediante el uso de un COSPEC V en posición móvil-terrestre. Durante el mes de agosto, los resultados reflejaron valores medios de 99, 28, y 23 toneladas diarias para las emisiones de S0 2 procedentes de UNELCO Caleti/las, Refinería y UNELCO Granadilla, respectivamente, mientras que estos valores medios durante el mes de septiembre fueron de 87, 113 y 18 toneladas diarias. La combinación del COSPEC con sistemas de OP-FTIR y cabinas para la medida de los niveles de inmisión de contaminantes atmosféricos permitirá estimar la emisión de otros contaminantes procedentes de estos focos industriales