An efficient GPU implementation for a faster simulation of unsteady bed-load transport

Computational tools may help engineers in the assessment of sediment transport during the decision-making processes. The main requirements are that the numerical results have to be accurate and simulation models must be fast. The present work is based on the 2D shallow water equations in combination with the 2D Exner equation. The resulting numerical model accuracy was already discussed in previous work. Regarding the speed of the computation, the Exner equation slows down the already costly 2D shallow water model as the number of variables to solve is increased and the numerical stability is more restrictive. In order to reduce the computational effort required for simulating realistic scenarios, the authors have exploited the use of Graphics Processing Units in combination with non-trivial optimization procedures. The gain in computing cost obtained with the graphic hardware is compared against single-core (sequential) and multi-core (parallel) CPU implementations in two unsteady cases

Reparative giant cell granuloma in a pediatric patient

Reparative giant cell granulomas are benign, infrequent tumors, of non-odontogenic origin, that develop at central or peripheral level. Peripherally located lesions are frequently denominated ?giant cell epulis?, and never correspond to true neoplasia, but rather to inflammatory reactions secondary to another lesion (hemorrhage, etc.). It should be taken into account, that in general, head and neck tumors of infancy usually demonstrate an atypical biological behaviour. Furthermore, the anatomicopathologic diagnosis is often compromised in this type of lesion. We present the case of a 6-year-old boy, who, three weeks after suffering a slight facial trauma, developed a painless, exophytic swelling of approximately 4 cm, with bleeding on palpation, in the ipsilateral hemimaxilla. The lesion demonstrated rapid, progressive and continuous growth. The facial CT and incisional biopsy confirmed the suspected diagnosis of reparative giant cell granuloma. The patient was surgically treated, carrying out a left marginal maxillectomy associated with the extirpation of the soft-tissue lesion. The resultant defect was reconstructed with a Bichat fat-pad providing the patient with optimal esthetic and functional results. The definitive anatomicopathologic report of the surgical piece is compatible with reparative giant cell granuloma

Performance of a transmutation advanced device for sustainable energy application

Preliminary studies have been performed to design a device for nuclear waste transmutation and hydrogen generation based on a gas-cooled pebble bed accelerator driven system, TADSEA (Transmutation Advanced Device for Sustainable Energy Application). In previous studies we have addressed the viability of an ADS Transmutation device that uses as fuel wastes from the existing LWR power plants, encapsulated in graphite in the form of pebble beds, cooled by helium which enables high temperatures (in the order of 1200 K), to generate hydrogen from water either by high temperature electrolysis or by thermochemical cycles. For designing this device several configurations were studied, including several reflectors thickness, to achieve the desired parameters, the transmutation of nuclear waste and the production of 100 MW of thermal power. In this paper new studies performed on deep burn in-core fuel management strategy for LWR waste are presented. The fuel cycle on TADSEA device has been analyzed based on both: driven and transmutation fuel that had been proposed by the General Atomic design of a gas turbine-modular helium reactor. The transmutation results of the three fuel management strategies, using driven, transmutation and standard LWR spent fuel were compared, and several parameters describing the neutron performance of TADSEA nuclear core as the fuel and moderator temperature reactivity coefficients and transmutation chain, are also presente

Diseño eficiente de elementos constructivos: fachadas.

Se presentan la metodología y algunos resultados para el análisis de elementos constructivos de fachada de edificios de viviendas en España desde una perspectiva de ciclo de vida, teniendo en cuenta el impacto ambiental de los materiales que componen dicha fachada, y sus prestaciones en la fase de uso de las viviendas. Para ello se ha tomado un modelo de vivienda, y se han estudiado diferentes escenarios para la construcción de la fachada. Los resultados obtenidos proporcionan datos de referencia del comportamiento de estos sistemas en España, y permiten detectar las mejores estrategias para reducir el consumo energético en viviendas, en una amplia variedad de situaciones posibles, que se dan tanto en fachadas de nueva construcción como en la rehabilitación de fachadas existentes. Las categorías de impacto estudiadas son: consumo de combustibles fósiles y cambio climático y las estrategias de diseño están vinculadas a las zonas climáticas, la orientación, renovación del aire interior, materiales y composición de fachada. Tanto el enfoque como los resultados obtenidos suponen una aportación para la valoración ambiental de las estrategias de diseño en una fase inicial de proyecto

Gold cementation with zinc powder from leaching solutions with ammonia-thiosulphate

9 páginas, 11 figuras, 7 tablas.[ES] Se estudió la cementación de oro con polvo de cinc desde soluciones con tiosulfato y amoniaco, evaluando la influencia de las siguientes variables: concentración de tiosulfato, concentración de amoniaco, pH, concentración de cobre y concentración de cinc. Los resultados han permitido establecer la gran importancia que tiene, en este proceso, la relación amoniaco/tiosulfato y cómo la presencia de impurezas como cobre y cinc inhiben el proceso de cementación.[EN] The cementation of gold with powder of zinc, from solutions with thiosulphate and ammonia, was studied. The variables evaluated were: thiosulphate concentration, ammonia concentration, pH, copper concentration and zinc concentration. The results have revealed the great importance of ammonia/thiosulphate relationship in this process and that the impurities presence like copper and zinc will to inhibit the cementation process.Los autores expresan sus agradecimientos por el patrocinio recibido de la Comisión Nacional de Investigación Científica y Tecnológica a través del proyecto FONDECYT 1020017.Peer reviewe

A model based on Hirano-Exner equations for two-dimensional transient flows over heterogeneous erodible beds

In order to study the morphological evolution of river beds composed of heterogeneous material, the interaction among the different grain sizes must be taken into account. In this paper, these equations are combined with the two-dimensional shallow water equations to describe the flow field. The resulting system of equations can be solved in two ways: (i) in a coupled way, solving flow and sediment equations simultaneously at a given time-step or (ii) in an uncoupled manner by first solving the flow field and using the magnitudes obtained at each time-step to update the channel morphology (bed and surface composition). The coupled strategy is preferable when dealing with strong and quick interactions between the flow field, the bed evolution and the different particle sizes present on the bed surface. A number of numerical difficulties arise from solving the fully coupled system of equations. These problems are reduced by means of a weakly-coupled strategy to numerically estimate the wave celerities containing the information of the bed and the grain sizes present on the bed. Hence, a two-dimensional numerical scheme able to simulate in a self-stable way the unsteady morphological evolution of channels formed by cohesionless grain size mixtures is presented. The coupling technique is simplified without decreasing the number of waves involved in the numerical scheme but by simplifying their definitions. The numerical results are satisfactorily tested with synthetic cases and against experimental data

Identifying Topics in Social Media Posts using DBpedia

This paper describes a method for identifying topics in text published in social media, by applying topic recognition techniques that exploit DBpedia. We evaluate such method for social media in Spanish and we provide the results of the evaluation performed

Study of the effects of magnetic braking on the lithium abundances of the Sun and solar-type stars

The study of lithium (Li) surface abundance in the Sun and young stellar globular clusters which are seemingly anomalous in present-day scenarios, as well as the influence of rotation and magnetic braking (MB) on its depletion during pre-main sequence (PMS) and main sequence (MS). In this work, the effects of rotational mixing and of the rotational hydrostatic effects on Li abundances are studied by simulating several grids of PMS and MS rotating and non-rotating models. Those effects are combined with the additional impact of the MB (with magnetic field intensities ranging between 3.0 and 5.0 G). The data obtained from simulations are confronted by comparing different stellar parameters. The results show that the surface Li abundance for the Sun like models at the end of the PMS and throughout the MS decreases when rotational effects are included, i.e. the Li depletion rate for rotating models is higher than for non-rotating ones. This effect is attenuated when the MB produced by a magnetic field is present. This physical phenomena impacts also the star effective temperature ($T_{\mathrm{eff}}$) and its location in the HR diagram. The impact of MB in Li depletion is sensitive to the magnetic field intensity: the higher it is, the lower the Li destruction. A direct link between the magnetic fields and the convective zone (CZ) size is observed: stronger magnetic fields produce shallower CZ's. This result suggests that MB effect must be taken into consideration during PMS if we aim to reproduce Li abundances in young clusters

Effects of Non-Circular Motions on Azimuthal Color Gradients

Assuming that density waves trigger star formation, and that young stars preserve the velocity components of the molecular gas where they are born, we analyze the effects that non-circular gas orbits have on color gradients across spiral arms. We try two approaches, one involving semi-analytical solutions for spiral shocks, and another with magnetohydrodynamic (MHD) numerical simulation data. We find that, if non-circular motions are ignored, the comparison between observed color gradients and stellar population synthesis models would in principle yield pattern speed values that are systematically too high for regions inside corotation, with the difference between the real and the measured pattern speeds increasing with decreasing radius. On the other hand, image processing and pixel averaging result in systematically lower measured spiral pattern speed values, regardless of the kinematics of stellar orbits. The net effect is that roughly the correct pattern speeds are recovered, although the trend of higher measured $\Omega_p$ at lower radii (as expected when non-circular motions exist but are neglected) should still be observed. We examine the Martinez-Garcia et al. (2009) photometric data and confirm that this is indeed the case. The comparison of the size of the systematic pattern speed offset in the data with the predictions of the semi-analytical and MHD models corroborates that spirals are more likely to end at Outer Lindblad Resonance, as these authors had already found.Comment: 32 pages, 15 figures, accepted to Ap