Search

Understanding the synergies between the Urban Heat Island (ICU) phenomenon and one of the extreme climatic events such as heat waves has become one of the great challenges of society that seeks to improve the quality of life. In this research, the Terrestrial Surface Temperature (TST) and the Urban Surface Heat Island (ICUS) have been determined using Sentinel-3 images of the city of Granada (Spain) during the months of July and August of the years 2019 and 2020. The purpose is to determine the possible synergies between both phenomena in an area classified as highly vulnerable to the effects of climate change. Using the Data Panel statistical analysis method, multivariate relationships were obtained during the heat wave periods. The results obtained, in line with previous research, indicate that TST and ICUS are intensified under heat wave conditions (Daytime: TST=2.2 °C and ICUS=0.2 °C; Nighttime: TST=4.4 °C and ICUS= 0.3 °C) and there are relationships between ICUS and wind direction and solar radiation that intensify in periods of heat wave. © 2022, Universidad Politecnica de Valencia.. All rights reserved.

This research was funded by the State Research Agency (AEI) of Spain and the European Regional Development Funds (ERDF), under project: PID2019-108761RB-I00., The need to tackle the urban heat island effect demands the implementation of cool surfaces as a mitigation strategy. This study comprehensively reviews the evolution of this research field from a materials perspective. It provides a bibliometric analysis of the relevant literature using the SciMAT software processing of bibliographic records from 1995 to 2020, for the evolution of cool surfaces. The results obtained show an increased interest in the field from 2011 to 2020, particularly for roof applications, and present the scientific evolution of reflective materials. According to the materials dimension adopted by the development of the research field, the study is refined from a bibliometric analysis of 982 selected records for the analysis of five themes: (i) Pigments; (ii) Phase change materials; (iii) Retroreflective materials; (iv) Ceramic materials; and (v) Glass. These materials present promising results in terms of their solar reflectance performances in the mitigation of the urban heat island phenomenon. At the end of this review, recommendations for future studies are provided for the creation of economic and environmentally friendly materials based on waste glass recycling. This study represents a valuable contribution that provides a scientific background with regard to cool surfaces from a materials perspective for future investigations., State Research Agency (AEI) of Spain, European Commission PID2019-108761RB-I00

Heritage preservation presents uncertainties in the global warming context. Both predicting the performance of environmental variables within the built environment and assessing the preservation conditions of heritage elements are today something of a challenge. Based on current monitorings, this study uses artificial intelligence to predict environmental performance in future scenarios. In addition, heritage elements are assessed according to threshold preservation values. The Chapel of the University of Seville was chosen as case study, applying both the threshold values from UNI 10829 and the performance index (PI) to assess the indoor environmental conditions. A total of 9 environmental treatment zones were identified according to temperature and humidity. To estimate the variables, the multilayer perceptron (MLP) was monitored and applied considering the time series of A2 future scenarios in each decade of the 21st century. The current MLP performances were analysed, thus showing a progressive reduction of the PI inside the church: at the end of the century, PI values oscillated between 6.6 and 6.8% in wooden objects, and between 1.8 and 2.3% in paintings. The results also showed a progressive increase in the number of hours and distance with respect to the optimal preservation values in the zones with a greater temperature and relative humidity, with cooling and dehumidification being the most effective strategies. This study represents a progress towards the most appropriate heritage preservation strategies by using an extrapolated methodology considering the climate change effect. Consejería de Economía, Conocimiento, Empresas y Universidad (Junta de Andalucía)

In recent years there has been an increase in the number of extreme weather events that lead to higher mortality, such as heat waves. This study carries out a new investigation that integrates the environmental quality parameters—the Surface Urban Heat Island (SUHI) and the Terrestrial Surface Temperature (LST)—during these periods of high temperatures and compares them with normal periods. The study of the relationship between these variables will allow improving the quality of life through new mitigation measures that will minimize the effects of climate change in urban areas. This study analyzes eight cities in the south of Spain (Andalusia) to assess environmental quality through gases SO2, NO2, CO, O3 and aerosols, obtained through Sentinel-5P satellite images, and the LST and SUHI obtained through Sentinel-3 images. Next, the results of periods of heat waves are compared with periods of normal environmental conditions during the summers of the years 2020 and 2021. The objective is to determine the possible impact of heat waves on environmental quality, as well as on the LST and SUHI of the investigated cities, which are located in an area identified as highly vulnerable to the effects of global warming. During the period of the heat wave and compared to the periods without a heat wave, a variety of environmental pollutants was found: SO2 (+165%), NO2 (+24%), CO (+8%), O3 (−4%) and aerosols (+193%). Both the LST and the SUHI suffered an average increase of 2.8 K. The results of this document can help to establish pollutant reduction mechanisms in periods prior to heat waves. This could minimize major effects on the population and provide sustainable development. © 2022 by the authors.

Esta tesis doctoral tiene como finalidad el estudio de las variables de proceso que afectan a las pérdidas de cobre en escorias procedentes de un Horno de Fusión Flash (Outotec) y de un Horno Eléctrico de tratamiento de escorias de la fundición Atlantic Copper S.L.U. (Huelva, España). Este estudio se llevó a cabo mediante la caracterización química-mineral y textural de muestras de fundidos industriales, el uso de la modelación termodinámica de los sistemas en equilibrio, y el desarrollo de metodologías de evaluación de las pérdidas de cobre y cálculos de proceso, basados en balances de masa y energía y los procesos de decantación de gotas de mata. Este trabajo consta de cinco capítulos. El capítulo 1 corresponde a la introducción donde se realiza una descripción del proceso productivo de la fundición Atlantic Copper y una revisión bibliográfica sobre los fundamentos físico-químicos de la fusión de cobre y las pérdidas de cobre en las escorias. En el capítulo 2 se presenta la propuesta de tesis definiéndose el objetivo general y los objetivos específicos alcanzados. El capítulo 3 describe la toma de muestras realizada a los distintos materiales y la preparación de las mismas para su análisis químico-mineral mediante distintas técnicas analíticas. El capítulo 4 presenta los resultados obtenidos y su discusión los cuales son divididos en 3 bloques: un primer bloque que recoge la caracterización de los materiales involucrados en el proceso de fusión flash, un segundo bloque que analiza desde el punto de vista del equilibrio termodinámico las escorias procedentes de la fusión flash y horno eléctrico de tratamiento de escorias, y un último bloque dedicado al análisis del proceso de fusión y decantación de la mata a través del desarrollo de metodologías de cálculos. El en capítulo 5 se presentan las conclusiones obtenidas. Tras la finalización de cada capítulo se recoge la bibliografía consultada, y al final de la memoria se adjuntan en anexos todos los análisis químicos, mineralógicos, granulométricos, coeficientes de distribución, matriz de cálculo y resultados secundarios que complementan al capítulo 4. El conjunto de estos estudios permitió realizar una evaluación y diagnóstico de los procesos con el objeto de aportar conocimiento a la práctica industrial para su optimización. Los resultados más importantes obtenidos son: § El estudio de caracterización químico-mineral y textural de los fundidos escoriamata una vez solidificados y muestreados en la corriente de gases del horno flash, mostró que la dimensión real del espacio reactivo del proceso de fusión tiene escala de gota micrométrica de fundido, haciendo intuir las limitaciones cinéticas del proceso. § La composición de los tipos de escorias I y II observada en los materiales arrastrados por los gases del horno flash, refleja distintas condiciones térmicas y fluctuaciones de la presión parcial de oxígeno y sirven de alimentación a las acreciones formadas en la salida de gases del horno. § Las escorias del Horno Flash se encuentran sobrecalentadas 109ºC por encima de la temperatura liquidus de la magnetita. El contenido de magnetita, el contenido de cobre disuelto y el grado de mata de las gotas de mata atrapada indican que las escorias tienen un grado de oxidación mayor que la mata del fondo del baño. Esta condición de no equilibrio favorece las pérdidas químicas de cobre en la escoria. § Las escorias del Horno Eléctrico muestran un bajo grado de reducción favoreciendo las pérdidas químicas de cobre y un sobrecalentamiento de 114ºC sobre el cotéctico magnetita-fayalita. § Las pérdidas de cobre en las escorias del horno flash y del horno eléctrico son principalmente de tipo químico. La cuantificación realizada estima un 73% de pérdidas químicas en el horno flash y un 85% en el horno eléctrico. § Los resultados del modelo de balance y energía del proceso de fusión muestran una adecuada concordancia a los valores industriales. La introducción de coeficientes de distribución y ratios moleculares en el modelo permitieron conocer la distribución del Zn y del Pb en las distintas fases del proceso y tener una estimación de las pérdidas químicas de cobre en la escoria en diferentes condiciones de operación. § Los modelos de decantación de gotas de mata en el baño de los hornos flash y eléctrico desarrollado en base a las propiedades reológicas, a la temperatura de la escoria líquida, a los tiempos de residencia y a la altura de la capa de escoria calculados, muestran una efectiva decantación con un elevado grado de limpieza., The aim of this doctoral thesis is to study the process variables that affect copper losses in slags from a Flash Smelting Furnace (Outotec) and an Electric Slag Treatment Furnace of the Atlantic Copper smelter S.L.U., (Huelva, Spain). This study was carried out through the chemical-mineral and textural characterization of samples of industrial melts, the use of thermodynamic modeling of systems in equilibrium, and the development of methodologies for the evaluation of copper losses and process calculations, based on mass and energy balances and the settling processes of the matte drops. This work consists of five chapters. Chapter 1 corresponds to the introduction where a description of the production process of the Atlantic Copper smelter and a bibliographic review on the physicochemical fundaments of copper smelting and copper losses in slags is made. In Chapter 2 the thesis proposal is presented, defining the general objective and the specific objectives achieved. Chapter 3 describes the sampling carried out on the different materials and their preparation for their chemical-mineral analysis using different analytical techniques. Chapter 4 presents the results obtained and their discussion, which are divided into 3 blocks: a first block that collects the characterization of the materials involved in the flash smelting process, a second block that analyzes from the point of view of thermodynamic equilibrium the slags from flash smelting and slag treatment electric furnace, and the last block dedicated to the analysis of the smelting and settling process of the matte through the development of calculation methodologies. In the chapter 5 the conclusions obtained are presented. After the completion of each chapter, the bibliography consulted is collected, and at the end of the report all the chemical, mineralogical, granulometric analyzes, distribution coefficients, calculation matrix, and secondary results that complement chapter 4 are attached as an annex. The set of these studies allowed to carry out an evaluation and diagnosis of the processes in order to contribute knowledge to industrial practice for its optimization. The most important results obtained are: § The study of chemical-mineral and textural characterization of the slag-matte melts once solidified and sampled in the gas stream of the flash furnace, showed that the real dimension of the reactive space of the smelting process has a scale of the melt micrometric drop, suggesting the kinetic limitations of the process. § The composition of slag types I and II observed in the materials entrained by the gases of the flash furnace reflect different thermal conditions and fluctuations in the oxygen partial pressure and serve as a feed for the accretions formed in the uptake of the furnace. § The slag from Flash Smelting Furnace is overheated 109ºC above the liquidus temperature of magnetite. The magnetite content, the dissolved copper content and the matte grade of the trapped matte droplets indicate that the slags have a higher degree of oxidation than the matte at the bottom of the bath. This non-equilibrium condition favors the chemical losses of copper in the slag. The slag from the Electric Furnace shows a low degree of reduction favoring the chemical losses of copper and an overheating of 114ºC over the cotéctic magnetitefayalite. § Copper losses in the flash furnace and electric furnace slag are mainly chemical. The quantification carried out estimates 73% chemical losses in the flash furnace and 85% in the electric furnace. § The results of the balance and energy model of the smelting process show an adequate concordance to the industrial values. The introduction of distribution coefficients and molecular ratios in the model allowed to know the distribution of Zn and Pb in the different phases of the process and to have an estimate of the chemical losses of copper in the slag under different operating conditions. § The models for the settling of droplets of matte in the bath of the flash and electric furnaces developed based on the rheological properties, the temperature of the liquid slag, the residence times, and the height of the slag layer calculated, show effective settling with a high degree of cleaning.

Due to the importance of concrete as a structural material and the pathologies that can be achieved by reinforced concrete structures when they are subjected to the action of fire both at the level of resistance and deformation, in this research we study the mechanical behavior of mass concrete with the addition of carbon nanofibers (CNFs) when exposed to the action of fire, in order to determine the improvements that this type of addition produces in concrete. To achieve this objective, compression break tests have been carried out on cylindrical concrete specimens incorporating CNFs. From the analysis of results, it can be concluded that the residual resistant capacity of concrete with the addition of 1% of CNFs by weight of cement subjected to the direct action of fire, is greater than that of concrete without additions, not obtaining better results, if the addition of CNFs increases to 2%. The addition of 1% of CNFs has not influenced the temperatures reached in the concrete, but produces a more homogeneous cooling and that the paste-aggregate bond is maintained despite thermal aggression, which decreases the spalling effect.

Currently, the scientific community has almost reached a consensus on the negative impacts of climate change. The causes of global warming are negative for sure, but are the impacts of these new climatic conditions negative and relevant? The answer is again probably yes, but not necessarily so. This study intends to evaluate the impacts of climate change on the functional deterioration of heritage buildings located in South Chile. For this purpose, an advanced artificial intelligence methodology, based on fuzzy logic, is used, and 79 heritage buildings, in five locations in South Chile, are analysed. The results obtained revealed that the predictions of climate change for this region, with an expected increase in temperature, associated with a reduction of the average annual precipitation, for the period 2045–2069, could actually benefit the functional performance of the heritage buildings analysed. Some lessons could be learned from the results, and the proposed model could be used for the prioritisation of maintenance activities, in heritage buildings, for the different locations analysed, considering the expected effect of climate changes, which in many other cases can be detrimental. © 2020 Elsevier Ltd