Use of tire derived aggregate in tunnel cut-and-cover

A case-history is reported in which tire derived aggregate (TDA) was successfully applied to reduce the weight of fill upon a cut-and-cover railway tunnel. Subsequent 3D numerical analyses are used to explore the effect of different assumptions about the constitutive model of the TDA material. Alternative dispositions of TDA around the tunnel section are also examined. Reductions of up to 60% in lining bending moment may be achieved. For the case analyzed the elastic description of the TDA has little influence on tunnel lining loads, although is important for fill settlement estimates.Peer ReviewedPostprint (author's final draft

Thermal and Lighting Consumption Savings in Classrooms Retrofitted with Shading Devices in a Hot Climate

Most educational buildings in southern Spain do not meet current energy requirements as weak thermal envelopes and the lack of cooling systems lead to severe discomfort in classrooms, especially when temperatures are above 30 °C. Given that global warming is expected to worsen this situation in coming decades, one of the first steps to be taken is to protect window openings from high levels of solar radiation by adding shading devices to reduce indoor temperatures and improve visual comfort. The aim of this research is to evaluate the reduction in thermal and lighting consumption in a classroom where a solar protection system in the form of an egg-crate shading device was installed. Two classrooms—one with an egg-crate device and another with no shading system—were monitored and compared for a whole year. The use of an egg-crate device in these classrooms reduced indoor operative temperatures during warmer periods while also improving indoor natural illuminance levels. Moreover, annual electric air conditioning consumption decreased by approximately 20%, with a 50% reduction in electric lighting consumption. These savings in electricity were largely conditioned by the use patterns observed in these ambient systems.Spanish government BIA2014-53949-RMinistry of Economy and Competitiveness, Spanish GovernmentEuropean Regional Development Fun

Concrete wave barriers to mitigate ground vibrations induced by railway traffic: a three-dimensional numerical study

[Abstract:] Continuous wave barriers are mitigation measures to reduce vibrations induced by railway traffic which have been well studied in technical literature. Nevertheless, there are not many studies about discontinuous concrete wave barriers. By this reason, in this paper continuous and discontinuous concrete wave barriers are studied and compared. With this objective, two theoretical cases with discontinuous barriers have been analysed and the results have been compared with those from both continuous barriers and without barriers cases. The study has been carried out with a dynamic numerical 3D FEM model formulated in the space/time domain, which has previously been validated by authors on the Lisbon-Oporto (Portugal) railway line. The numerical results show the discontinuous barriers with a small separation between axles (less than twice the thickness of the continuous barrier) are an efficient measure in the reduction of vibrations, reaching values of insertion loss of up to 13 dB. So, these could be a very interesting alternative to continuous barriers, in order to conjugate a somewhat lower level of reduction of vibration at a considerable lower cost

Análisis de la respuesta elástica no lineal de las capas de base conformadas con materiales granulares en las secciones de la Instrucción 6.1 y 6.2 IC

[Resumen:] En el presente trabajo, se van a comprobar las secciones de la Instrucción de Carreteras (6.1 y 2 IC) que incorporen en su estructura capas de materiales granulares. Sin embargo, en esta oportunidad, en vez de emplear como herramienta de cálculo un sistema multicapa se utilizarán dos modelos numéricos para estudiar la respuesta de estas capas granulares: un modelo tridimensional (en FLAC3D), empleando un esquema explícito de diferencias finitas, y un modelo axilsimétrico (en SIGMA/W), que trabaja con elementos finitos

Analysing digital genres: function and functionality in corporate websites of computer hardware

The aim of this paper is to characterize corporate websites by describing some linguistic, semiotic and pragmatic properties regarding function and functionality. We also try to define the current prevailing set of functionality features of hardware corporate websites. For the purposes of our research we have analysed an English corpus of corporate websites of computer hardware from the United States. This research has been carried out as a part of the DIGALTT (Digital Genre Analysis for Language Teaching and Translation) Project, currently funded by the University of Las Palmas de Gran Canaria. Conclusions are intended to be applied to the teaching of English for Specific Purposes and Web Site Translation

Coastal Cliff Exposure and Management

[Abstract:] Coastal cliffs cover about 75% of the world's coastlines. Many of these cliffs suffer severe erosion problems, which are mainly caused by wave action and lead to important damages. The main objective of this work is to propose and apply a methodology to characterize and map wave exposure levels for the management of cliff coasts. The methodology proposed consists of a number of steps. First, a statistical characterization of the wave climate in deep water is performed. Second, relevant sea states are propagated towards the cliff by means of a numerical model. Then, the results are used to assess the distribution of significant wave heights and wave power along the cliff toe. Finally, four exposure levels are defined based on the wave power values at the cliff, and exposure zones are mapped accordingly along the cliff. This approach is illustrated with a case study – the Catedrales Cliffs and Beach, a tourism hotspot in Galicia (NW Spain) where erosion caused loss of human life. We find that exposure levels are primarily influenced by the nearshore bed morphology, which controls wave refraction, shoaling and breaking, as well as by the geometry and orientation of the cliff, with some parts more exposed than others to the prevailing wave direction. On the islets off the cliff the windward faces have a greater level of exposure, since the leeward faces are protected by the islets themselves and lower water depths. The rocky outcrops that occur at the cliff toe in some sections act as emerged (submerged) breakwaters under low (high) tide conditions, dissipating wave power and thus reducing wave exposure. The methodology proposed in this work enables coastal managers to prevent the personal and material damages derived from cliff erosion by focusing remedial measures where they are most needed.Ministerio de Ciencia, Innovación y Universidades; FJCI-2017-3178

Repercusiones posturales con los estiramientos en flexión de tronco y las pruebas de distancia dedos-planta y distancia dedos-suelo

La postura corporal no es un concepto estrictamente estático, siendo preciso analizar aquellos movimientos y ejercicios que se realizan con gran frecuencia en la actividad física y que repercuten de forma directa en diversas estructuras del aparato locomotor, fundamentalmente en el raquis. En el presente artículo de revisión se ofrece un estudio de dos ejercicios ampliamente utilizados en el ámbito clínico y de la actividad física, como son los estiramiento en flexión de tronco y los tests de flexibilidad de Distancia Dedos-Planta y Distancia Dedos-Suelo, que frecuentemente se efectúan con dudosa corrección. Podremos comprobar cómo su ejecución incorrecta influye negativamente sobre la estabilidad del raquis y estableceremos estrategias para su realización de forma correcta

Hot mix asphalt using C&D waste as coarse aggregates

[Abstract] This article evaluates the possibility of designing hot asphalt mix road pavements using Construction and demolition waste as coarse recycled aggregates. The percentages of recycled aggregates used in the mixtures were: 0%, 20%, 40% and 60%. Cement and lime were used as fillers. The mixtures made with coarse recycled aggregates complied with the Marshall technical specifications for low volume roads. The mixtures also showed good resistance to permanent deformation evaluated by means of wheel tracking tests. Nevertheless, the mixtures made with RA may have insufficient durability due to their high susceptibility to water action which was evaluated using stripping tests

LA DEFENSA CONSTITUCIONAL DE DERECHOS DE LOS PARLAMENTARIOS VINCULADOS A LA COMISIÓN DE DELITOS

A raíz de los hechos que se ven registrados en la realidad nacional peruana, actores políticos están siendo evaluados en un comportamiento típico respecto de una presunta ejecución de corrupción, especialmente a raíz del descubrimiento de los actos ejecutados en América Latina por Odebrecht. Sin embargo, este contexto está representando un verdadero problema tanto social, político como legal, por cuanto los contextos que se van descubriendo no sólo permiten detallar actos visibles de corrupción pero que no logran vincular un contexto procedimental en el ámbito jurisdiccional eficiente que finalmente conduzca a la imposición de una condena contra un presunto autor de un delito contra la administración pública. Una referencia muy importante si tomamos en cuenta que los actores evaluados en este contexto han ostentado altas funciones en la gestión gubernamental en el país, tanto a nivel de Presidentes de la República como gobernadores regionales o alcaldes, y que por ello lo delimitaremos al ámbito del estudio de casos vinculados a la esfera parlamentaria. Referencia muy coyuntural que permite evaluar el límite de capacidades del Ministerio Público y del Poder Judicial ante un elevado número de personas que podrían plantear acciones de garantía en defensa de sus intereses, a pesar de los hechos de corrupción en los cuales se han visto involucrados

Modelos mecánicos de los materiales granulares sueltos empleados en firmes de carreteras

[Resumen:] En los firmes de carreteras los materiales granulares sueltos desempeñan un importante papel estructural. Esto es así porque por un lado, durante la etapa de construcción del firme soportan el tráfico de obra y proporcionan un cimiento sobre el cual las capas superiores puedan situarse y compactarse y, por otro lado, en un firme terminado actúan como amortiguadores de las cargas del tráfico. En este artículo se expone una breve descripción de algunos modelos de predicción del comportamiento resiliente de los materiales granulares bajo las cargas del tráfic