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Artículos en revistas In this paper we apply stochastic dual dynamic programming decomposition to a nonconvex multistage stochastic hydrothermal model where the nonlinear water head effects on production and the nonlinear dependence between the reservoir head and the reservoir volume are modeled. The nonconvex constraints that represent the production function of a hydro plant are approximated by McCormick envelopes. These constraints are split into smaller regions and the McCormick envelopes are used for each region. We use binary variables for this disjunctive programming approach and solve the problem with a decomposition method. We resort to a variant of the L-shaped method for solving the MIP subproblem with binary variables at any stage inside the stochastic dual dynamic programming algorithm. A realistic large-scale case study is presented. info:eu-repo/semantics/publishedVersion

Artículos en revistas Liberalization policies, the challenges of integrating distributed generation resources, and the recent flattening of electricity demand due to the economic crisis and technological change have led to lower returns for European electricity suppliers. Innovative and sustainable business models are needed to serve electricity customers while reflecting the operational needs of the system and maintaining supplier financial viability. This paper describes a novel model of Integrated Energy Services that encompasses distributed generation (DG) and demand response (DR) resources for industrial customers. We further reflect on some of the market opportunities and regulatory drivers for the development of similar schemes across Europe. info:eu-repo/semantics/publishedVersion

The development of heat transfer fluids (HTF) and heat storage materials (HSM) is crucial to design concentrating solar plant (CSP). Binary alkaline nitrate mixtures are currently used as sensible thermal energy storage materials. However, multi-component nitrate/nitrite systems were proposed as possible better candidates. In particular, ternaries mixtures containing sodium, potassium, and calcium are extremely promising as thermal fluids, given their reduced toxicity and greater cost-effectiveness. Nevertheless, very few data are present in the scientific literature regarding the correspondent phase diagram, and only the properties of specific compositions are reported. For this reason, a regular solution model was developed and employed in this work, and validated by comparing the simulation results with experimentally obtained phase change values. In particular, given that the common calorimetric techniques are impracticable for detecting the transition temperatures of calcium containing nitrate mixtur...

A Life Cycle Assessment (LCA) with focus on carbon footprint, followed by Life Cycle Costing (LCC) of municipal solid waste (MSW) management were conducted in a residential area of a medium-sized European city of 80,000 inhabitants. The initial results showed high environmental impacts and lack of economic sustainability, due to the high amounts of waste landfilled, the low extent of separate collection, low performance of mechanical-biological treatment as well as absence from alternatives to landfilling of non-recyclable materials. Taking this result as a baseline scenario, three improvement.s were tested with the aim of turning the carbon footprint of the local MSW management system into a neutral value: (i) increased separate collection of recyclables, (ii) enhanced biogas production and (iii) refuse-derived fuel (RDF) production. Successively adding the improvements, three alternative improved scenarios were defined, until reaching a negative carbon footprint, meaning that an optimised system would avoid GHG emissions. The proposed changes were sufficient to achieve carbon neutrality, as well as reduce overall environmental impacts, but were not enough for achieving economic sustainability due to the great influence of collection costs, especially for separate collection. It was concluded that by using an adequate combination of several treatment options and increasing the separate collection of recyclable materials it is possible to turn MSW management into a carbon neutral activity as well as improve its economic balance.

Abstract Rigid ceramic filters have emerged as the most promising technology for cleaning of hot gases due to their resistance to attack by aggressive gases and high temperatures. Their potential may be further extended by using them in combination with injection of a dry sorbent to remove acid gases and other chemical contaminants. A crucial factor in their successful utilisation is the ability of the cleaning pulse to remove the deposited cake effectively from the filter surface. In this study, laboratory experiments have been carried out using a single ceramic candle filter. The non-steady-state behaviour of the filter in the initial period of filtration was followed. ‘Patchy’ cleaning of the filter was observed and is consequently identified as the major cause of the inefficiency of filter cleaning indicated by the measured residual pressure drops. A simple correlation has been proposed to determine the cleaned fraction from pressure differences as a measure of the efficiency of cleaning. The conditioning curves have been successfully simulated using a recently developed probabilistic model and it has been shown that the model can also be applied to simulate the experimental results obtained in a pilot plant operating at high temperatures. The modelling results are consistent with the experimental observation that patchy cleaning with a thin residual dust layer in the cleaned areas can explain the conditioning behaviour.

Thermokinetics of Biochar production.

Treball final de Grau en Psicologia. Codi: PS1048. Curs acadèmic 2015-2016 El estresante estilo de vida de la sociedad actual junto con la mala concepción sobre las posibles consecuencias del consumo de alcohol podrían ser algunas de las causas de que actualmente el alcohol sea una de las drogas más consumidas a nivel mundial según la OMS. Sin embargo, a pesar de todos los avances de la neurociencia, el mecanismo exacto de cómo actúa el alcohol en el SNC nos es aún desconocido. El objetivo de este trabajo es tratar de plantear y dar pruebas a favor de una hipótesis sobre como podría actuar realmente el alcohol en el cerebro. El método de este trabajo consta del análisis de 4 estudios que muestran las manipulaciones de diferentes mediadores de calcio y AMPc-­‐PKA y las consecuencias de esas manipulaciones a nivel molecular, celular, neurobiológico y conductual. Por una parte los resultados obtenidos nos muestran que posiblemente, estos mediadores de calcio tengan una función muy importantes a la hora de explicar el mecanismo de acción del alcohol en el cerebro. Pero, no obstante, no son suficientes evidencias como para afirmar con completa claridad y certeza que este sea el mecanismo exacto de actuación del alcohol en el SNC. The stressfull way of life of our nowadays society in adition to the missconception of the potencial consequences from alcohol consum could be some of the reasons for why alcohol is the worldwide most consumed drug according to OMS. However, besides all the neuroscience developments, the true mechanism of alcohol functionament on the SNC has been not proved. The method of this paper consists of the analysis of 4 studies that show the manipulations of the different mediators of calcium and cAMP-­‐PKA and the consequences of these manipulations at a molecular, cellular, neurobiological and behavioural level. The results, in one hand, show that is possible that those mediators of calcium are important for understands the true mechanism of how alcohol works in the brain. However, there are no enough evidences to completely agree that this is the exact mechanism by which alcohol acts at a central level.

The need to understand how past societies dealt with major climate events has been acknowledged by scholarship, however the existing archaeological record in most upland areas of Northern Britain and Ireland is not granular enough to avoid false ‘cause and effect’ conclusions and requires refinement to generational levels where possible. This project is an effort to generate a more granular and refined chronology through expanding existing chronologies of selected archaeological zones using radiocarbon dating of untested archived samples, new samples and re-evaluation of finds by typologies.