Índices para la evaluación de un seguidor solar

The usage of solar trackers in solar energy technologies represents an alternative to increase the capture of solar radiation. However, the costs involved convert it into a prohibitive technology, having indexes and procedures that allow for its evaluation and determination of the viability of its use is of vital importance at the time of deciding its implementation and so to form the objective of this study. In the investigation carried out, the indexes of average gain, comparative efficiency and profitability are introduced and a procedure for the evaluation is developed, as a contribution to the decision-making process as to whether or not to use a solar tracker. It is confirmed that the use of trackers is completely viable when used with higher power technologies. Furthermore, it is shown that theoretically, the average gain index is higher than the values currently registered in scientific literature. Such factors support the possibility of designing and developing solar trackers with a higher gain, lower production costs and lower consumption indexes, as a way for their mass use in low power photovoltaic generators.El uso de los seguidores solares como tecnología de aprovechamiento de energía solar representa una alternativa para incrementar la captación de radiación solar. Sin embargo, sus costos lo convierten en una tecnología prohibitiva, por lo que disponer de índices y procedimientos que permitan su evaluación para determinar la viabilidad de uso es una herramienta de extrema importancia a la hora de decidir sobre su utilización y constituye el objetivo de este trabajo. Con la investigación realizada se introducen los índices de ganancia media, eficiencia comparativa y de utilidad y se desarrolla un procedimiento de evaluación, como contribución a la toma de decisiones sobre el uso o no de un seguidor solar. Se corrobora que su uso es totalmente viable mientras mayor es la potencia de las tecnologías en las cuales se utiliza. Además, se muestra que teóricamente el índice medio de ganancia es mayor que los valores registrados actualmente en la literatura científica. Tales elementos apoyan la posibilidad de diseñar y desarrollar seguidores solares con mayor ganancia, menores costos de fabricación y menores índices de consumo, como vía para su utilización masiva en generadores fotovoltaicos de baja potencia

EXPERIENCIAS DE LA UNIVERSIDAD ANTONIO NARIÑO, SEDE TUNJA, EN EL APROVECHAMIENTO DE LAS FUENTES DE ENERGÍA RENOVABLE

Las zonas no electrificadas son una realidad presente en países en vías de desarrollo, siendo la causa fundamental los altos costos de inversión. Esta situación se manifiesta en algunos municipios del departamento de Boyacá, por lo que en la sede Tunja de la Universidad Antonio Nariño se desarrollan investigaciones relacionadas con el desarrollo de tecnologías que aprovechen la energía solar y eólica para ser utilizadas en zonas no interconectadas. En el trabajo se presentan las experiencias utilizando materiales locales y reciclables, con precios competitivos en el mercado. Los resultados obtenidos son: solicitud de patente de un calefactor solar, un seguidor solar hidráulico mecánico y una máquina manufacturadora de conductos; se han construido turbinas verticales y horizontales a nivel de prototipo y un disco solar concentrador. Todos esos logros, basados en estudios realizados desde el año 2015, han sido materializados por los estudiantes en sus trabajos de grado

Numerical models of neutrino and gamma-ray emission from magnetic reconnection in the core of radio-galaxies

Non-blazar radio-galaxies emitting in the very-high-energy (VHE; >100 GeV) regime offer a unique perspective for probing particle acceleration and emission processes in black hole (BH) accretion-jet systems. The misaligned nature of these sources indicates the presence of an emission component that could be of hadronic origin and located in the core region. Here we consider turbulent magnetic reconnection in the BH accretion flow of radio-galaxies as a potential mechanism for cosmic-ray (CR) acceleration and VHE emission. To investigate if this scenario is able to account for the observed VHE data, we combine three numerical techniques to self-consistently model the accretion flow environment and the propagation of CRs plus electromagnetic cascades within the accretion flow zone. Here we apply our approach to the radio-galaxy Centaurus A and find that injection of CRs consistent with magnetic reconnection power partially reproduce the VHE data, provided that the accretion flow makes no substantial contribution to the radio-GeV components. The associated neutrino emission peaks at $\sim10^{16}$ eV and is two orders of magnitude below the minimum IceCube flux.Comment: To be published in the Proceedings of International Conference on Black Holes as Cosmic Batteries: UHECRs and Multimessenger Astronomy - BHCB2018 12-15 September, 2018, Foz du Iguazu, Brasi

Uso del desempeño de los índices de peligro de incendio como herramienta para el pronóstico de ocurrencias

One of the tools used for the evaluation of fire danger are the danger indices, allowing the reduction of the large losses caused by them. The Pinar del Río province is the first in Cuba in terms of the occurrence of fires. This research aims to demonstrate the use and importance of the performance of the Nesterov indices, FMA (Monte Alegre Formula), FMA+ (Modified Monte Alegre Formula) and (FPR) Pinar del Río Formula for the Pinar del Río province as a tool help in the decision-making process. The meteorological database and the fires that occurred in the province were used and the performance of the danger indices was determined through the Skill score and the percentage of success. The FPR index presented the lowest value of Skill score, however, it showed the highest value of success percentage and the best behavior of the distribution of degrees of danger, which globally demonstrates that it is the one with the best performance compared to the rest. of the evaluated indices. It was shown that the use of this index contributes to better planning and reduction of the costs of combating forest fires in the province of Pinar del Río.Una de las herramientas utilizadas para la evaluación del peligro de incendio son los índices de peligro, permitiendo la reducción de las cuantiosas pérdidas ocasionadas por los mismos. La provincia Pinar del Río es en Cuba la primera en cuanto a ocurrencia de incendios. Esta investigación tiene como objetivo demostrar el uso e importancia del desempeño de los índices Nesterov, FMA (Fórmula de Monte Alegre), FMA+ (Fórmula de Monte Alegre Modificada) y (FPR) Fórmula de Pinar del Río para la provincia Pinar del Río como herramienta de ayuda en el proceso de toma de decisiones. Se utilizó la base de datos meteorológicos y de los incendios ocurridos en la provincia y se determinó el desempeño de los índices de peligro mediante el Skill score y el porcentaje de éxito. El índice FPR presentó el menor valor de Skill score no obstante mostro el valor más alto de porcentaje de éxito y el mejor comportamiento de la distribución de los grados de peligro lo cual demuestra de forma global que es el de mejor desempeño en comparación con el resto de los índices evaluados. Se demostró que la utilización de este índice contribuye a una mejor planificación y reducción de los costos de combate de los incendios forestales en la provincia de Pinar del Río

Ensayo para la determinación del estado de conservación de la vegetación

The constant search of strategies that they lead towards the sustainable development makes the environmental indicators exposition more and more frequent. The target of these indicators is to give useful information for the control of the conservation of the environment. The use of formulae that allow quantifying the conservation of the vegetation makes possible the securing of an indicative value of the state of naturalness of the vegetation. Also, the use of natural types of habitat instead of phytosociology associations allows simplifying the proposed formulation, obtaining completely valid results. Finally, the effect of the change of scale in the calculation of the value of the index does not suppose changes in the validity of the obtained value. Nevertheless, we must consider that the values obtained are only comparable in works realized to equal scale

RELACIÓN ENTRE VARIABLES METEOROLÓGICAS E INCENDIOS FORESTALES EN LA PROVINCIA PINAR DEL RÍO, CUBA

Comprender la relación existente entre variables meteorológicas e incendios forestales es importante con vistas a una gestión de las actividades propias del manejo integral del fuego dentro de límites económicamente viables, socialmente aceptables y ecológicamente apropiados. Esta investigación fue desarrollada con el objetivo de argumentar las relaciones existentes entre variables meteorológicas tales como temperatura del aire, humedad relativa, precipitación y velocidad del viento y los incendios forestales en la provincia Pinar del Río, Cuba. La base de datos meteorológicos utilizados fue facilitada por el Centro Meteorológico Provincial de Pinar del Río y los datos de incendios forestales fueron obtenidos en el Cuerpo de Guardabosques de Pinar del Río a través de los correspondientes registros de ocurrencias de incendios. Toda la información utilizada se refiere al período del 01/01/2010 al 31/12/2014, totalizando cinco años de observaciones. Para los análisis estadísticos se utilizó el programa informático IBM SPSS Statistic versión 22. Los resultados muestran que la distribución anual de las variables meteorológicas tiene relación directa o inversa con la distribución de las ocurrencias de incendios y las áreas quemadas en la provincia Pinar del Río durante el período 2010-2014. Independientemente de lo anterior, las correlaciones entre variables meteorológicas e incendios forestales fueron bajas o muy bajas. No obstante, es posible demostrar que el mes de abril es el más propicio para la ocurrencia de los incendios forestales.Palabras clave:   Manejo del fuego; prevención de incendios forestales; factores meteorológicos; propagación del fuego; combustible forestal disponible

Thermal and light irradiation effect on the electrocatalytic performance of Hemoglobin modified Co3O4-g-C3N4 nanomaterials for oxygen evolution reaction

The oxygen evolution reaction (OER) plays a key role in the water splitting process and a high energy conversion efficiency is essential for the definitive advance of hydrogen-based technologies. Unfortunately, the green and sustainable development of electrocatalysts for water oxidation is nowadays a real challenge. Herein, a successful mechanochemical method is proposed for the synthesis of a novel hemoglobin (Hb) modified Co3O4/g-C3N4 composite nanomaterial. The controlled incorporation of cobalt entities as well as Hb functionalization, without affecting the g-C3N4 nanoarchitecture, was evaluated using different physicochemical techniques, such as X-ray diffraction, N2-physisorption, scanning electron microscopy, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The beneficial effect of the resulting ternary bioconjugate together with the influence of the temperature and light irradiation was investigated by electrochemical analysis. At 60 °C and under light exposition, this electrocatalyst requires an overpotential of 370 mV to deliver a current density of 10 mA·cm−2, showing a Tafel slope of 66 mV·dec−1 and outstanding long-term stability for 600 OER cycles. This work paves a way for the controlled fabrication of multidimensional and multifunctional bio-electrocatalysts

Diseño de un sistema de mantenimiento proactivo basado en la metodología RCM como propuesta para el mantenimiento de las plantas eléctricas tipo GPU del GANCA

This article develops a proposal whose purpose was to design a maintenance alternative based on Reliability that leads to providing greater operational availability in the Ground Electric Power Supply Units for Aircraft (GPU) of the Caribbean Naval Group (GANCA) in the city of Barranquilla. As a result of applying the Reliability Centered Maintenance (RCM) methodology and recognizing, anticipating, and controlling failure modes through maintenance tasks, the following activities are required: i) collection, ii) classification, and iii) categorization (i.e., equipment, subsystems, and systems, down to the component level, development of matrices, criticality analysis, causes, and consequences). With this, GANCA will have a solution for the maintenance of its GPUs that will serve as a reference to impact the increase in availability and improve the effectiveness of maintenance, and that can be used as a reference for other equipment that provides ground support in Colombian Naval Aviation. From a practical point of view, it is recommended to use the scheme proposed in this work.En este artículo se desarrolló una propuesta de trabajo cuyo propósito fue diseñar una alternativa de mantenimiento basada en confiabilidad para brindar mayor disponibilidad operativa en las Unidades de alimentación de Potencia eléctrica a Aeronaves en Tierra (GPU), del Grupo Aeronaval del Caribe (GANCA) en la ciudad de Barranquilla. Como resultado de la aplicación de la metodología de Mantenimiento Centrado en Confiabilidad (RCM), se logró el desarrollo de matrices, análisis de criticidad, causas y consecuencias a partir de la recolección, clasificación y categorización de los equipos, subsistemas y sistemas hasta el nivel de componentes; esto con el fin de reconocer, anticipar y controlar los modos de falla a través de tareas de mantenimiento. Con esto, el GANCA tendrá una solución para el mantenimiento de sus GPU, que servirá de referencia para impactar en el aumento de la disponibilidad y con ello mejorar la efectividad de mantenimiento, que podrá ser usada como referencia para otros equipos de apoyo terrestre en la Aviación Naval de Colombia. Desde el punto de vista práctico, se recomienda usar el esquema propuesto en este trabajo

Adaptation and performance of Nesterov, FMA and FMA+ fire indices in Macurije Forest Company, Cuba

 ResumoEsta pesquisa foi desenvolvida com os objetivos de ajustar e comparar o desempenho dos índices de Nesterov, Fórmula de Monte Alegre (FMA) e Fórmula de Monte Alegre Alterada (FMA+)na Empresa Florestal Macurije, província Pinar del Río, Cuba. Os dados meteorológicos e de ocorrência de incêndios, referentes ao período 01/01/2006 a 31/12/2011, foram fornecidos pelo Centro Meteorológico, pelo Instituto de Hydroeconomia e pelo Corpo de Guarda-Bosques da Província. Dois cenários foram considerados: um utilizando a precipitação registrada na Estação Meteorológica de Isabel Rubio e outro considerando, além dela, 11 pluviômetros distribuídos na área do estudo. Foram considerados como não indicativos de probabilidade de ocorrência de incêndios as classes de perigo Nulo e Pequeno e como indicativo da probabilidade de ocorrências as classes de perigo Médio, Alto e Muito Alto. A partir dessa definição, foram calculados os valores de skill score e porcentagem de sucesso dos índices nos dois cenários, utilizando-se as escalas atuais e ajustadas das classes do perigo. Os resultados indicaram um melhor desempenho para os três índices com as escalas ajustadas, sendo mais eficiente o índice FMA+. Para este, os valores de skill score e porcentagem de sucesso foram 0,0737 e 57,10%, respectivamente.AbstractAdaptation and performance of Nesterov, FMA and FMA+ fire indices in Macurije Forest Company, Cuba. This research aimed to adapt Nesterov, Monte Alegre Formula (FMA) fire danger indices, and Modified Monte Alegre Formula (FMA+) to the Macurije Forest Company conditions as well as to compare their performances. The meteorological and forest fire occurrences databases were provided by the Meteorological Center, Hydro-economy Institute, and Forest Guard Corps of the Pinar del Rio province. All data referred to the period from 01/01/2006 to 31/12/2011. Two different scenarios were considered: one considering the rainfall measured at the Isabel Rubio Meteorological Station and other with the inclusion of 11 pluviometers distributed throughout the focused area. The performance of indices was evaluated by skill score methodology. Null and Low fire danger classes were considered as indicative of no fire occurrence and Medium, High and Very High classes as indicative of fire occurrence. Based on this definition the skill score and the success percentages of the indices had been calculated in the two proposed scenarios. The current and the adjusted scales of the danger indices were used. The results pointed to better performance for the three indices with the adjusted scale. The FMA+ index was the most efficient to forecast the fire danger in the focused region. The skill score and the success percentage of this index were 0.0737 and 57.10%, respectively.Keywords: Fire danger index; forest fire; fire prevention.  AbstractThis research aimed to adapt Nesterov, Monte Alegre Formula (FMA) fire danger indices, and Modified Monte Alegre Formula (FMA+) to the Macurije Forest Company conditions as well as to compare their performances. The meteorological and forest fire occurrences databases were provided by the Meteorological Center, Hydro-economy Institute, and Forest Guard Corps of the Pinar del Rio province. All data referred to the period from 01/01/2006 to 31/12/2011. Two different scenarios were considered: one considering the rainfall measured at the Isabel Rubio Meteorological Station and other with the inclusion of 11 pluviometers distributed throughout the focused area. The performance of indices was evaluated by skill score methodology. Null and Low fire danger classes were considered as indicative of no fire occurrence and Medium, High and Very High classes as indicative of fire occurrence. Based on this definition the skill score and the success percentages of the indices had been calculated in the two proposed scenarios. The current and the adjusted scales of the danger indices were used. The results pointed to better performance for the three indices with the adjusted scale. The FMA+ index was the most efficient to forecast the fire danger in the focused region. The skill score and the success percentage of this index were 0.0737 and 57.10%, respectively.Keywords: Fire danger index; forest fire; fire prevention