Sistemas de gestión de energía para microrredes: evolución y desafíos en el marco de la transición energética

Context: Microgrids have been gaining space and credibility in terms of research and real applications. Technological maturity and new regulations have allowed these types of systems to position themselves as a real alternative to increase the coverage of the energy service and improve its quality. One of the biggest challenges of microgrids is the management of resources and their synchronization with conventional grids. In order to overcome the inconvenience of synchronizing and managing the components of a microgrid, research on management systems has been conducted, which usually consist of a set of modules and control strategies that manage the available resources. However, these studies have not reached unanimity on the best method to perform these tasks, which is why it is necessary to perform a systematic collection of information and clearly define the state of research in energy systems management for this type of network. Method: Based on the above, a systematic mapping was carried out in this article, wherein a significant number of papers that have contributed to this area were compiled. Taxonomies were generated based on the nature of the variables collected. These variables correspond to the data or information that enters and/or leaves the microgrid management system, such as meteorological variables, power, priority loads, intelligent loads, economic, operating states, and binary outputs. Conclusions: It was observed that, despite the advances in studying different techniques and strategies microgird control and management, other factors that may affect performance have not been covered in a relevant way, such as the nature of variables and microgrid topology, among others.     Contexto: Las microrredes eléctricas han venido ganando espacio y credibilidad a nivel de investigación y aplicaciones reales. La madurez tecnológica y las nuevas regulaciones han permitido que este tipo de sistemas se posicionen como una alternativa real para aumentar la cobertura del servicio de energía y mejorar su calidad. Uno de los mayores retos de las microrredes es la gestión de los recursos y su sincronización con la red convencional. Con el fin de superar el inconveniente de sincronizar y gestionar los componentes de la microrred, se ha investigado sobre sistemas de gestión, los cuales normalmente consisten en un conjunto de módulos y estrategias de control que administran los recursos disponibles. Sin embargo, estas investigaciones no han llegado a una unanimidad sobre el mejor método para realizar estas tareas, por lo cual se hace necesario realizar una recopilación sistemática de información y definir claramente el estado de la investigación en gestión de sistemas de energía para este tipo de redes. Método: Con base en lo anterior, en este artículo se realizó un mapeo sistemático, donde se recopiló un importante número de artículos que han aportado a este campo. Se generaron taxonomías basadas en la naturaleza de las variables que se recopilaron. Dichas variables corresponden a los datos o información que entran y/o salen del sistema de gestión de la microrred, tales como variables meteorológicas, potencia, cargas prioritarias, cargas inteligentes, económicas, estados de operación y salidas binarias. Conclusiones: Se observa que, a pesar de los avances en el estudio de las diferentes técnicas y estrategias de control y gestión de microrredes, no se han cubierto de forma relevante otros factores que pueden afectar al rendimiento, como la naturaleza de las variables y la topología de la microrred, entre otros

High Strain Rate Characterization of Thermoplastic Fiber-Reinforced Composites under Compressive Loading

Experimental study on the mechanical behavior of polyphenylene sulfide (PPS)-based composite laminates reinforced with carbon and glass fibers subjected to different strain rates under compression load is reported. Quasi-static tests have been carried out using an electromechanical universal testing machine at three different strain rates, while dynamic tests were done using a split-Hopkinson pressure bar (SHPB) apparatus at two pressure setups in the gas chamber. High-speed imaging system was used to monitor failure process during dynamic test, and these images were used to measure strain by digital image correlation (DIC) in order to compare the DIC-based measurements performed with the SPHPB strain gauges and quasi-static results. Fractography analysis was also performed to identify the main failure mechanisms induced at different strain rates

PROPOSTA DE METODOLOGIA PARA A RECUPERAÇÃO DA PRODUÇÃO CIENTÍFICA EM CIÊNCIA DA INFORMAÇÃO NA BASE BRAPCI

Propõe uma metodologia de atribuição de pesos a campos de busca em processos de Recuperação da Informação (RI) na Base Referencial de Artigos de Periódicos em Ciência da Informação (Brapci). Define características de uma metodologia de RI para determinar a relevância de estudos em uma área temática específica. Realiza um teste piloto na Brapci para a validação da proposta, com o tema epistemologia da Ciência da Informação. Discute duas vertentes, a primeira, relativa à recuperação da informação e a segunda, sobre a temática de busca para ilustrar o alcance do método. A proposta de hierarquização de artigos por pesos, atribuídos aos campos título, palavra-chave e resumo, categoriza os documentos mais relevantes para a temática buscada. Conclui que os resultados da aplicação do método adéquam-se às bases teóricas da área e à importância dos seus autores para o domínio específico e que a produção recuperada abrange documentos relevantes para outras áreas relacionadas à CI, reiterando seu caráter interdisciplinar

Updated Evolutionary Sequences for Hydrogen-deficient White Dwarfs

We present a set of full evolutionary sequences for white dwarfs with hydrogen-deficient atmospheres. We take into account the evolutionary history of the progenitor stars, all the relevant energy sources involved in the cooling, element diffusion in the very outer layers, and outer boundary conditions provided by new and detailed non-gray white dwarf model atmospheres for pure helium composition. These model atmospheres are based on the most up-to-date physical inputs. Our calculations extend down to very low effective temperatures, of ∼2500 K, provide a homogeneous set of evolutionary cooling tracks that are appropriate for mass and age determinations of old hydrogen-deficient white dwarfs, and represent a clear improvement over previous efforts, which were computed using gray atmospheres.Instituto de Astrofísica de La Plat

Native pigs: a climate resilient business enterprise

The International Institute of Rural Reconstruction (IIRR) and CCAFS introduced the low external input project on small-livestock system to communities in Guinayangan Climate-Smart Village (CSV) in the Philippines. This is part of the Developing Scalable Approaches for Community Based Adaption project of IIRR. Climate-smart agriculture approaches, including those in livestock production, were introduced to help build farm resilience in anticipation of the impacts of climate change. The experiences shared in this publication was generated over 6 years. Replication are now seen in nearly all of the Philippine Department of Agriculture CSVs

Selective fractionation of free glucose and starch from microalgae using aqueous two-phase systems

Microalgae are a promising source of lipids, pigments, proteins and carbohydrates, which are valuable compounds for many industries. However, optimal fractionation and valorization of all produced compounds is necessary to improve the economic viability of microalgae production. This paper aims to understand the fractionation of microalgae carbohydrates (free glucose and starch) in aqueous two-phase systems. Three aqueous two-phase systems were investigated to efficiently and mildly separate carbohydrates from disrupted Neochloris oleoabundans. This strain contains 16 w/w% of proteins, 48 w/w% total fatty acids and 27 w/w% carbohydrates when cultivated under saline water and nitrogen depletion conditions. The protein content decreases and the amount of fatty acids and carbohydrates increases notably under stress conditions and glucose becomes the main carbohydrate in this microalgae. Glucose is present in the disrupted microalgae as part of polymeric carbohydrates (starch) or in monomeric form (free glucose). With the aqueous two-phase system Polyethylene Glycol 400 - Cholinium dihydrogen phosphate (PEG400-ChDHp) microalgal free glucose is fractionated up to a recovery of 99% to the most hydrated bottom phase in a single step. Simultaneously, a recovery of 70% is reached for microalgal starch in the interface after two additional liquid-liquid extractions with PEG400-ChDHp. The final fractions obtained were free of pigments.publishedVersionPaid Open Acces

Assessment of Guinea Grass Panicum maximum under Silvopastoral Systems in Combination with Two Management Systems in Orellana Province, Ecuador

Climate change has increased the interannual and seasonal variation in the average temperature and precipitation rate, which determine forage availability globally. Similar patterns of change have occurred in tropical regions, and Ecuador is no exception. This region includes other influencing factors, such as the conversion of tropical forests to extensive pastures. Therefore, this study was carried out to evaluate guinea grass (Panicum maximum) cultivated under silvopastoral systems with different management strategies in both of the seasons of the study region in Ecuador (rainy season and dry season). A randomized complete block design was used for the experiment, with three repetitions and three treatments. Agronomic measures, forage production, chemical composition, animal responses, and soil properties were evaluated. Data were analyzed with the Mixed model of SAS. Differences in all evaluated parameters were observed between treatments, and silvopastoral systems (SPSs) produced better results than conventional grass monoculture. Furthermore, there was a strong seasonal effect on forage production, chemical composition, and soil properties. Therefore, management of Panicum maximum with well-planned grazing can enhance animal responses and help to retain natural resources, lowering the pressure on forests

Influence of Litter Size at Birth on Productive Parameters in Guinea Pigs

A study was conducted at the Escuela Superior Politècnica de Chimborazo, Ecuador, to evaluate the influence of litter size of guinea pigs (Cavia porcellus) on their development and to establish the economic profitability of the production system. Forty-eight animals were used, distributed into litters of two, three, and four rodents per litter, with a balanced diet and green fresh alfalfa for the weaning, growth, and fattening stage, the rodents and litters were randomly selected, applying the statistical model completely randomly and evaluating different variables across 120 days. The litters of three guinea pigs obtained the best productive responses and economic profitability. With respect to sex, the males presented better productive behavior, greater economic increase, and less cost, evidencing that mixed feeding influences the number of guinea pigs per birth in terms of growth and development. The results serve to improve guinea pig meat production for the rural population

Energy Management Systems for Microgrids: Evolution and Challenges within the Framework of the Energy Transition

Context: Microgrids have been gaining space and credibility in terms of research and real applications. Technological maturity and new regulations have allowed these types of systems to position themselves as a real alternative to increase the coverage of the energy service and improve its quality. One of the biggest challenges of microgrids is the management of resources and their synchronization with conventional grids. In order to overcome the inconvenience of synchronizing and managing the components of a microgrid, research on management systems has been conducted, which usually consist of a set of modules and control strategies that manage the available resources. However, these studies have not reached unanimity on the best method to perform these tasks, which is why it is necessary to perform a systematic collection of information and clearly define the state of research in energy systems management for this type of network. Method: Based on the above, a systematic mapping was carried out in this article, wherein a significant number of papers that have contributed to this area were compiled. Taxonomies were generated based on the nature of the variables collected. These variables correspond to the data or information that enters and/or leaves the microgrid management system, such as meteorological variables, power, priority loads, intelligent loads, economic, operating states, and binary outputs. Conclusions: It was observed that, despite the advances in studying different techniques and strategies microgird control and management, other factors that may affect performance have not been covered in a relevant way, such as the nature of variables and microgrid topology, among others