Energy, exergy and thermoeconomic analysis of an industrial solar pond

This study evaluates the viability of an industrial salinity gradient solar pond during two operating seasons (2014 and 2015). The Granada solar pond was built to supply low-temperature heat (up to 60 °C) to satisfy the temperature requirements of the flotation unit in a mineral processing plant (Solvay Minerales in Granada (Spain)). Energy analysis indicates that the non-convective zone (NCZ) and the upper convective zone (UCZ) have low efficiencies because these zones have a low capacity to store heat, and no heat extractions are carried out from these zones. In contrast, heat extraction in the lower convective zone (LCZ) has a positive impact on the system because it increases the capacity of the solar pond to store energy. Higher efficiencies were achieved in the second operation period in the LCZ, since higher amount of heat was extracted during this period. The overall exergy efficiency of the LCZ after the first and second operation periods was 1.6% and 2.3%, respectively. The solar pond works at temperatures close to room temperature and thus the exergetic efficiency decreases significantly. Regarding the thermoeconomic analysis, the cost of exergy stored is studied in this work, using two different approaches, by estimating the minimum price for exergy stored or the minimum surface area that ensure the thermoeconomic viability. The price of the stored exergy tends to decrease inversely to the price of fuel oil. Thus, the cost of the stored exergy must be four to five times higher than the price of fuel oil for the solar pond system to be feasible. On the other hand, solar pond technology is affected by economies of scale; the larger the solar pond, the higher the inflation rates and the lower the cost reduction rates that can be accommodated. This implies that estimating the cost of the stored exergy is complex due to the variability of the processes involved and can lead to erroneous interpretations when evaluating the viability of a solar pond from a thermoeconomic perspective.Peer ReviewedPostprint (author's final draft

Local, Regional, and Remote Seismo‐Acoustic Observations of the April 2015 VEI 4 Eruption of Calbuco Volcano, Chile

The two major explosive phases of the 22–23 April 2015 eruption of Calbuco volcano, Chile, produced powerful seismicity and infrasound. The eruption was recorded on seismo-acoustic stations out to 1,540 km and on five stations (IS02, IS08, IS09, IS27, and IS49) of the International Monitoring System (IMS) infrasound network at distances from 1,525 to 5,122 km. The remote IMS infrasound stations provide an accurate explosion chronology consistent with the regional and local seismo-acoustic data and with previous studies of lightning and plume observations. We use the IMS network to detect and locate the eruption signals using a brute-force, grid-search, cross-bearings approach. After incorporating azimuth deviation corrections from stratospheric crosswinds using 3-D ray tracing, the estimated source location is 172 km from true. This case study highlights the significant capability of the IMS infrasound network to provide automated detection, characterization, and timing estimates of global explosive volcanic activity. Augmenting the IMS with regional seismo-acoustic networks will dramatically enhance volcanic signal detection, reduce latency, and improve discrimination capability

Lo glocal y el turismo. Nuevos paradigmas de interpretación.

El estudio del turismo se realiza desde múltiples escalas y enfoques, este libro aborda muchos temas que es necesario discutir desde diversas perspectivas; es el caso de la reflexión sobre la propia disciplina y sus conceptos, así como los asuntos específicos referidos al impacto territorial, los tipos de turismo, las cuestiones ambientales, el tema de la pobreza, la competitividad, las políticas públicas, el papel de las universidades, las áreas naturales protegidas, la sustentabilidad, la cultura, el desarrollo, la seguridad, todos temas centrales documentados y expuestos con originalidad y dominio del asunto. Lo multiescalar es básico para la comprensión del sistema turístico, sistema formado de procesos globales, regionales y locales. El eje de discusión del libro es lo glocal, esa interacción entre lo nacional y local con lo global

Cine en compañía para prevenir enfermedades

El proyecto “Cine en compañía para prevenir enfermedades” es continuación del proyecto iniciado en 2017 (INNOVA-Docencia 18/2018, ApS-UCM 18/2019) y se encuadra en el campo de Salud Pública, higiene y prevención de enfermedad, dirigido a personas desfavorecidas o en riesgo de exclusión social. En esta edición se ha ampliado el área de conocimiento y profesores participantes, incluyendo no solo enfermedades infecciosas, como en ediciones anteriores, sino otras del ámbito de la Bioquímica y Biología Molecular. El proyecto es multidisciplinar e interfacultativo (21 tutores: profesores, colaboradores postdoctorales, doctorandos, estudiantes participantes en ediciones anteriores y técnico de laboratorio, de las Facultades de Farmacia, Biología y Medicina y del Hospital 12 de Octubre) y en él han participado 41 estudiantes de distintos Grados (Biología, Bioquímica, Ciencia y Tecnología de los Alimentos, Derecho, Farmacia, Ingeniería Electrónica) y Postgrados (Máster en Biología Sanitaria, y en Microbiología y Parasitología: Investigación y Desarrollo; Doctorado en Bioquímica y Biología Molecular) y participantes en la asignatura Transversal “Ciencia para la Sociedad”. La necesidad social detectada y atendida es la situación de algunos colectivos, por ejemplo, personas sin hogar, mujeres en exclusión, adictos a drogas, presidiarios o familias residentes en áreas no salubres, de una mayor exposición a determinadas enfermedades debido a sus condiciones de vida (enfermedades infecciosas, mentales, metabólicas derivadas de adicciones o alcoholismo), además de que encuentran escasas posibilidades de conocer cómo prevenirlas y la forma adecuada de recibir tratamiento. Adicionalmente, y no menos importante, acusan una carencia severa de compañía, atención y escucha de sus necesidades. Los estudiantes de universidad que cursan estudios en el campo de Ciencias y Ciencias de la Salud estudian estas enfermedades, por lo que pueden ayudar a estos colectivos en la mejora de prácticas higiénico-sanitarias, así como al acceso a la información para su prevención y tratamiento. Las actividades desarrolladas en el proyecto han consistido en el acompañamiento y desarrollo de una actividad lúdica mediante la proyección de películas comerciales que traten una enfermedad de interés en el colectivo a atender, seguida de coloquio para ayudar a conocer las formas adecuadas de prevención y tratamiento. Los equipos de 4-5 estudiantes (de distintas titulaciones y cursos) y dos tutores (senior y junior) han realizado varias visitas a centros sociales atendidos por Fundaciones con las que existe convenio de la UCM (centros de día para personas sin hogar, mujeres en exclusión, discapacitados o presidiarios, gestionados por Cáritas, Hogar-Sí, Diaconía, Medinacelli). Han investigado en profundidad las enfermedades que afectan y de interés del grupo atendido, seleccionado y analizado críticamente películas adecuadas, preparado materiales divulgativos (carteles, juegos) y diseñado y analizado encuestas para evaluar su actividad por parte de las personas atendidas y los coordinadores de los centros. Los resultados de las encuestas a todos los participantes (tutores, estudiantes, centros) y la recogida de opiniones y memorias de los estudiantes muestran una alta consecución de los objetivos de aprendizaje previstos, refuerzo de contenidos específicos de los estudios y, sobre todo, trabajo y adquisición de competencias transversales como trabajo en equipo, coordinación y asunción de responsabilidades, análisis crítico o expresión científica divulgativa. En cuanto a los objetivos de servicio, destaca la utilidad del proyecto en atención e información a los colectivos, la aplicación de los estudios a situaciones reales en atención a personas desfavorecidas y el valor social del proyecto

Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

Mapping density, diversity and species-richness of the Amazon tree flora

Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.Publisher PDFPeer reviewe

Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology

In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics

Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology

In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics