440 research outputs found

    Hacia una arquitectura financiera regional. El sistema SUCRE

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    Dentro del camino hacia la arquitectura financiera regional una de las propuestas más recientes y polémicas ha resultado la creación del Sistema Unitario de Compensación Regional (SUCRE). Lanzada en la Tercera Cumbre Extraordinaria de los países del ALBA el 26 de Noviembre de 2008 esta iniciativa entró en vigor el 27 de Enero de 2010 con los objetivos explícitos de propiciar un desacople progresivo de las divisas internacionales y en particular del dólar estadounidense (usd); incrementar el comercio intrarregional, reducir las asimetrías a través de proyectos conjuntos de inversión y crear las bases para desarrollar una moneda común entre los países miembros. Acerca del SUCRE y su futuro existen muchas preguntas, algunas sin respuestas conclusivas y no cabe otra opción que manejar una duda razonable y esperar por el desarrollo de las relaciones entre los países firmantes, por la marcha del proceso de integración regional y en particular por el futuro del esquema ALBA

    Culturing requirements and commercial quality of four different species of Ulva (Ulvales, chlorophyta)

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    The commercial production of Ulva spp. by aquaculture is gaining in importance due both to the qualitative and quantitative increase in the use of the harvested biomass and its new applications in inland IMTA techniques. However, very little is known about the specific culturing requirements and commercial quality of the different species of Ulva. The aim of this work is to try from this point of view four Ulva species that could be grown in southern Europe: U. australis, U. fasciata, U. ohnoi and U. rigidaPostprint (author's final draft

    A new way to obtain climate files in areas with the presence of microclimates by applying the Sandia method: a Galician case study

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    In order to obtain reliable energy simulation results, it is essential to have accurate climate files corresponding to specific geographical locations. The present work describes a selection process of the Typical Meteorological Months (TMM) that will generate the Typical Meteorological Years (TMY) in eight locations of the Community of Galicia for an analysis period between 2008 and 2017 (10 years). The region of Galicia, located in the northwest of the Iberian Peninsula, due to its particular orography, is prone to the generation of differentiated microclimates in relatively close locations. The process of selecting the typical meteorological months has been carried out following the Sandia Laboratories method. In the present work, data from terrestrial meteorological stations have been combined with solar radiation data obtained from satellite images. Finally, for the validation and comparative study of results, files have been generated in Energy Plus Weather (epw) format. Trends have been checked and typical statistics have been used to analyse the correlations between the files generated with the Sandia method, and the usual reference files (LT, WY, BY). It is observed that with the eight files generated, new differentiated climates are detected, which will affect the improvement of the precision of the energy simulations of buildings that are going to be carried out. For example, in the case of the Campus Lugo and Pedro Murias stations, located in the same climatic zone according to Spanish regulations, differences are observed in the annual averages: DTm (13.7%), WV (41%) or GHI (9%)

    Characterizaton of Thermochemical Conversion Processes in a Technical-Scale Fixed-Bed Reactor: Pyrolysis and Gasification

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    Consolidated industrial application of biomass thermochemical conversion processes, such as pyrolysis and gasification, requires the development and application of control and optimization techniques. To this end, on-line process characterization, regarding mainly product distribution and composition under similar conditions as the ones encountered in industrial applications is needed. In the present study, slow pyrolysis and updraft gasification of thermally thick particles in a technical scale fixed-bed reactor are carried out under several process conditions. Different raw materials are used: pine wood chips, beech-wood spheres and cellulose. In pyrolysis, the increasing influence of transport phenomena in the conversion process due to the use of a technical-scale reactor and thermally thick wood particles is analysed through the temperature distribution inside the bed during the process together with the char properties characterization taken from four different positions inside the bed. The influence of process conditions, such as the N2 flow rate, on the products composition and distribution is also analysed. In gasification, the influence of the air to fuel ratio on the product gas composition is characterized, as well as the qualitative evolution of polycyclic aromatic hydrocarbons (PAH) representative species in the volatiles vapours by applying laser-induced fluorescence (LIF)

    Study of the effects of thermally thin and thermally thick particle approaches on the Eulerian modeling of a biomass combustor operating with wood chips

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    Two particle treatments, thermally thin and thick, are applied to Eulerian combustion modeling for biomass packed beds and tested through the simulation of an experimental plant. The paper shows the efficiency of the Eulerian approach for large packed beds and tests the behavior of both particle treatments, tested with in-bed and flame temperatures and released volatiles measurements at different locations, which is not common in the literature for a full size boiler. Both approaches are implemented in a model with a comprehensive framework that includes several submodels for the thermal conversion kinetics, bed motion, heat and mass transfer with the gas phase, and gas flow and reaction. Two experiments are performed with wood chips fuels with different moisture contents. The simulations of the two cases result in reasonably good predictions for both particle treatments. The results are similar for higher moisture content and, for the low-moisture test, the bed temperature distribution and reaction fronts are slightly different due to the different predictions of the drying and devolatilization fronts. The volatile measurements show that the T. Thin model results in slightly more accurate predictions than the T. Thick, possibly because the wood chips have a more thermally thin behaviorMinisterio de Ciencia, Innovación y Universidades | Ref. PID2021-126569OB-I00Universidade de Vigo/CISU
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