An efficient multi-objective evolutionary approach for solving the operation of multi-reservoir system scheduling in hydro-power plants

This paper tackles the short-term hydro-power unit commitment problem in a multi-reservoir system ? a cascade-based operation scenario. For this, we propose a new mathematical modeling in which the goal is to maximize the total energy production of the hydro-power plant in a sub-daily operation, and, simultaneously, to maximize the total water content (volume) of reservoirs. For solving the problem, we discuss the Multi-objective Evolutionary Swarm Hybridization (MESH) algorithm, a recently proposed multi-objective swarm intelligence-based optimization method which has obtained very competitive results when compared to existing evolutionary algorithms in specific applications. The MESH approach has been applied to find the optimal water discharge and the power produced at the maximum reservoir volume for all possible combinations of turbines in a hydro-power plant. The performance of MESH has been compared with that of well-known evolutionary approaches such as NSGA-II, NSGA-III, SPEA2, and MOEA/D in a realistic problem considering data from a hydro-power energy system with two cascaded hydro-power plants in Brazil. Results indicate that MESH showed a superior performance than alternative multi-objective approaches in terms of efficiency and accuracy, providing a profit of $412,500 per month in a projection analysis carried out.European CommissionMinisterio de Economía y CompetitividadComunidad de Madri

Assembly of Soft Electrodes and Ion Exchange Membranes for Capacitive Deionization

The responsible use of water, as well as its reuse and purification, has been a major problem for decades now. In this work, we study a method for adsorbing ions from aqueous solutions on charged interfaces using highly porous electrodes. This water purification process is based on the electric double layer concept, using the method known as capacitive deionization (CDI): If we pump salty solutions through the volume comprised between two porous electrodes while applying a potential difference to them, ions present in the solution are partially removed and trapped on the electrode surfaces. It has been well established that the use of carbon electrodes in combination with ion exchange membranes (membrane-CDI) improves the efficiency of the method above that achieved with bare activated carbon. Another approach that has been tested is based on coating the carbon with polyelectrolyte layers, converting them into “soft electrodes” (SEs). Here we investigate the improvement found when combining SEs with membranes, and it is shown that the amount of ions adsorbed and the ratio between ions removed and electrons transported reach superior values, also associated with a faster kinetics of the process. The method is applied to the partial desalination of up to 100 mM NaCl solutions, something hardly achievable with bare or membrane-covered electrodes. A theoretical model is presented for the ion transport in the presence of both the membrane and the polyelectrolyte coating.This research was funded by MINECO, Spain, grant number PGC2018-098770-B-I00 and RYC-2014-1690

Stacking of capacitive cells for electrical energy production by salinity exchange

Publisher's link: http://www.sciencedirect.com/science/article/pii/S0378775316303676?np=yHa estado embargado durante 1 año, hasta julio 2017In this paper we explore methods for stacking individual cells in order to increase the amount of energy that can be extracted from salinity gradient cycles (capmix methods). Each of the cells consists of a pair of parallel electrodes made of activated carbon particles, either bare or coated by a layer of polyelectrolyte. In these methods, energy is produced based on the modifications in the electrical double layer (EDL) structure in the pores of the carbon particles upon exchange of the salinity of the surrounding medium. In the case of the bare carbon particles, the electrodes are externally charged in presence of high-salt concentration, and discharged after exchanging the solution for a dilute one (sea- vs. river-water cycles). In a first stacking approach, we simply connect the electrodes side-by-side and only the outermost ones can be connected to the external source. Using a stack where potential and current between cells can be measured, it is shown that only the external electrodes seem to work, and it is suggested that this is a consequence of internal short-circuit currents between oppositely charged electrodes of different cells through the electrolyte. In contrast, the side-by-side configuration is operational if coated electrodes are used.MICINN, Spain (Project FIS2013-47666-C3-1R)RYC-2014-16901 (MINECO)FEDER Funds E

Polylectrolyte- versus membrane-coated electrodes for energy production by Capmix salinity exchange methods

La versión final publicada se puede encontrar en: Journal of Power Sources, 302(20): 387-393 (2016). http://dx.doi.org/10.1016/j.jpowsour.2015.10.076In this paper we analyze the energy and power achievable by means of a re- cently proposed salinity gradient technique for energy production. The method, denominated soft electrode or SE, is based on the potential di erence that can be generated between two porous electrodes coated with cationic and anionic polyelectrolytes. It is related to the Capacitive Donnan Potential (CDP) tech- nique, where the electrical potential variations are mostly related to the Donnan potential, of ion-selective membranes in the case of CDP, and of the polyelec- trolyte coating in SE. It is found that although SE is comparable to CDP in terms of energy production, it presents slower rates of voltage change, and lower achieved power. The separate analysis of the response of positively and neg- atively coated electrodes shows that the latter produces most of the voltage rise and also of the response delay. These results, together with electrokinetic techniques, give an idea on how the two types of polyelectrolytes adsorb on the carbon surface and a ect di erently the di usion layer. It is possible to suggest that the SE technique is a promising one, and it may overcome the drawbacks associated to the use of membranes in CDP.MINECO FIS2013-47666-C3-1-RJunta de Andalucía, PE2012-FQM0694European Union 7th Framework Programme (FP7/2007–2013) under agreement No. 25686

An efficient multi-objective evolutionary approach for solving the operation of multi-reservoir system scheduling in hydro-power plants

This paper tackles the short-term hydro-power unit commitment problem in a multi-reservoir system ? a cascade-based operation scenario. For this, we propose a new mathematical modeling in which the goal is to maximize the total energy production of the hydro-power plant in a sub-daily operation, and, simultaneously, to maximize the total water content (volume) of reservoirs. For solving the problem, we discuss the Multi-objective Evolutionary Swarm Hybridization (MESH) algorithm, a recently proposed multi-objective swarm intelligence-based optimization method which has obtained very competitive results when compared to existing evolutionary algorithms in specific applications. The MESH approach has been applied to find the optimal water discharge and the power produced at the maximum reservoir volume for all possible combinations of turbines in a hydro-power plant. The performance of MESH has been compared with that of well-known evolutionary approaches such as NSGA-II, NSGA-III, SPEA2, and MOEA/D in a realistic problem considering data from a hydro-power energy system with two cascaded hydro-power plants in Brazil. Results indicate that MESH showed a superior performance than alternative multi-objective approaches in terms of efficiency and accuracy, providing a profit of $412,500 per month in a projection analysis carried out.European CommissionAgencia Estatal de InvestigaciónComunidad de Madri

Prevalence of Child-Adolescent Chronic Pathologies in Cantabria (Spain)

Objective: The study of child-adolescent chronic pathologies (CACPs) is a relevant aspect for public health and this knowledge is necessary for prevention and control. Our objective was to analyze the prevalence and distribution of the main CACPs in the region of Cantabria (Spain). Methodology: The stratified data were obtained from the whole child and adolescent population treated by the Cantabria Health Service in the year 2019. The prevalence of the most frequent CACPs and their differences based on sex, urban non-urban location and levels of complexity and risk were assessed. The statistical analysis was performed with the SPSS program. Results: 90,163 people aged from birth to 17-year-olds were analyzed (48.7% girls and 51.3% boys). At least one CACP was present in 29.1% of the population studied (26,234). CACPs were less prevalent in girls (25.5%) than in boys (32.6%), (?2, p <0.001; OR: 0.708; IC 95%: 0.688-0.729). The two most common CACPs were: asthma (16.7%) and attention deficit hyperactivity disorder (6.3%). Multimorbidity occurred in 1,978 girls (4.5%) and in 2,916 boys (6.3%). Those chronic pathologies were less prevalent in urban areas (26.5%) than in non-urban areas (28.0%), (?2, p <0.001; OR: 1.037; 95% CI: 1.023-1.052). CACPs level of complexity was slightly higher in girls and in non-urban locations. The level of risk was similar when sex and location where compared. Conclusion: CACPs were very common in the age group studied. Our data indicate that not only is there a need for a greater number of descriptive studies, but also a greater accuracy on the clinical records of CACPs. These actions would allow the implementation of effective programs for prevention and early detection of CACPs and better treatment and control, once they are diagnosed

Polyelectrolyte-coated carbons used in the generation of blue energy from salinity differences

This is the unedited version of this manuscript. The publisher's edited version can be reached at this URL: http://pubs.rsc.org/en/content/articlelanding/2014/cp/c4cp03527e#!divAbstractIn this work we present a method for the production of clean, renewable electrical energy from the exchange of solutions with different salinities. Activated carbon films are coated with negatively or positively charged polyelectrolytes by well-established adsorption methods. When two oppositely charged coated films are placed in contact with an ionic solution, the potential difference between them will be equal to the difference between their Donnan potentials, and hence, energy can be extracted by building an electrochemical cell with such electrodes. A model is elaborated on the operation of the cell, based on the electrokinetic theory of soft particles. All the features of the model are experimentally reproduced, although a small quantitative difference concerning the maximum opencircuit voltage is found, suggesting that the coating is the key point to improve the efficiency. In the used experimental conditions, we obtain a power of 12.1 mW/m2. Overall, the method proves to be a fruitful and simple approach to salinity-gradient energy production. Obtaining energy from salinity differences asDepartamento de Física AplicadaThe research leading to these results received funding from the European Union 7th Framework Programme (FP7/2007-2013) under agreement No. 256868. Further financial sup- ports from Junta de Andalucía, project PE2012-FQM694, and Ministerio de Economía y Competitividad (Spain), project FIS2013-47666-C3-1-R

Multi-ionic effects on energy production based on double layer expansion by salinity exchange

The edited version of the manuscript can be obtained at: Delgado et al., J. Colloid Interface Science (2014); DOI http://dx.doi.org/10.1016/j.jcis.2014.08.009It has been recently shown that the free energy change upon salinity mixing in river mouths can be harvested taking advantage of the fact that the capacitance of charged solid/liquid interfaces (electrical double layers, EDLs) depends strongly on the ionic composition of the liquid medium. This has led to a new generation of techniques called Capmix technologies, one of them (CDLE or Capacitive energy extraction based on DL Expansion) based precisely on such dependence. Despite the solution composition playing a crucial role on the whole process, most of the research carried out so far has mainly focused on pure sodium chloride solutions. However, the effect of other species usually present in river and sea waters should be considered both theoretically and experimentally in order to succeed in optimizing a future device. In this paper, we analyse solutions of a more realistic composition from two points of view. Firstly, we find both experimentally and theoretically that the presence of ions other than sodium and chloride, even at low concentrations, may lead to a lower energy extraction in the process. Secondly, we experimentally consider the possible effects of other materials usually dispersed in natural water (mineral particles, microbes, shells, pollutants) by checking their accumulation in the carbon films used, after being exposed for a long period to natural sea water during CDLE cycles.Universidad de Granada. Departamento de Física AplicadaThe research leading to these results received funding from the European Union 7th Framework Programme (FP7/2007-2013) under agreement No. 256868. Financial support from Junta de Andalucia (Project PE2012-FQM 694) and MINECO (Project FIS2013-4766-C3-1-R) is also acknowledged. One of us, M.M.F., is grateful to the University of Granada for her FPU grant

Arte comunitario como herramienta de inclusión : experiencias en el Taller de Expresión Artística del Centro Penitenciario Madrid IV de Navalcarnero

La Educación Artística, como herramienta para la integración social, puede funcionar como canal mediador en diferentes contextos para fomentar el pensamiento crítico y localizar lugares de encuentro e intercambio de perspectivas. En España se han desarrollado varios proyectos en los que esta disciplina se ha incluido en los programas educativos de prisiones para contribuir a la reinserción y el enriquecimiento cultural de los internos. En el presente artículo se expone la experiencia del taller de arte en el Centro Penitenciario Madrid IV, prisión ubicada en Navalcarnero, dentro de la Comunidad de Madrid. Esta iniciativa es coordinada por la asociación Solidarios para el Desarrollo, que trabaja dentro de la acción social y comunitaria con el objetivo de crear espacios que propicien el acercamiento socio-cultural. Se abordan en primer lugar los antecedentes existentes, para después profundizar en la actividad desde la primera toma de contacto en la intervención didáctica hasta la materialización y valoración de la actividad, dividendo la experiencia en dos bloques que explican tanto la acción desde la parte social como desde la parte artística. Los resultados que derivarán en conclusiones se obtienen a partir de las fichas de seguimiento de objetivos, así como de la extracción de categorías recogidas en la sesión de evaluación. Así, esta experiencia puede convertirse en un referente para las prácticas artísticas en contextos de privación de libertad como herramienta de mediación y reflexión comunitaria.

Why Should We Be Concerned with the Use of Spent Coffee Grounds as an Organic Amendment of Soils? A Narrative Review

Spent coffee grounds (SCG) are produced in massive amounts throughout the world as a bio-residue from coffee brewing. However, SCG are rich in carbohydrates, proteins, lipids, bioactive compounds and melanoidins, which are macromolecules with chelating properties. Additionally, SCG have showed potential applications in several fields such as biotechnology (bioethanol, volatile aromatic compounds, carotenoids, fungi and enzymes), energy production (combustion, pyrolysis, torrefaction, gasification, hydrothermal carbonization) and environmental sciences (composting). This review will focus on the last of these applications. SCG improve soil quality by increasing their chemical, physicochemical, physical properties and biological fertility. However, SCG inhibit plant growth at very low concentrations (1%) due to i. the stimulation of microbial growth and consequent competition for soil nitrogen between soil microorganisms and plant roots; ii. the presence of phytotoxic compounds in SCG, such as polyphenols. The SCG transformations that have proven to eliminate these compounds are vermicomposting and pyrolysis at 400 degrees C. However, it has been pointed out by some studies that these compounds are responsible for the chelating properties of SCG, which makes their elimination not recommended. The use of SCG as biochelates has also been studied, generating a residue-micronutrient mixture for the biofortification of edible plants.Andalusian Ministry of Economic Transformation, Knowledge Industry and Universities PY20_00585Plan Propio de Investigacion y Transferencia of the University of Granada under the program "Intensificacion de la Investigacion, modalidad B