Doctoral School

Reading date: 07/10/2024

• GONZALEZ ROMERO, ADOLFO: Understanding sediment formation processes, properties and dust emission potential in desert dust hotspot regions
  
  Author: GONZALEZ ROMERO, ADOLFO
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Article-based thesis
  Deposit date: 16/07/2024
  Reading date: 07/10/2024
  Reading time: 10:00
  Reading place: UPC, Campus Nord Building C1. Classroom: 002 C/Jordi Girona, 1-3 08034 Barcelona
  Thesis director: QUEROL CARCELLER, XAVIER | PEREZ GARCIA-PANDO, CARLOS
  Committee:
       PRESIDENT: DE LA ROSA DÍAZ, JESÚS DAMIAN
       SECRETARI: CASTILLO FERNÁNDEZ, SONIA
       VOCAL: DI BIAGIO, CLAUDIA
  Thesis abstract: Desert dust, primarily composed of mineral particles from arid and semiarid regions, irnpacts the Earth's atmosphere, climate, ecosystems and human health. To better eva!uate these impacts, desert dust models must reduce uncertaintles, which partly stem from inadequate characterization of sediment properties. In this study, samples were co!lected from four regions (Morocco, lceland, Mojave Desert and Jordan), including crusts (ephemeral lake top sediments), paved sediments (eroded crusts by aeolian processes), sediments and aeolian ripples (transported by wind). These were analysed far particle size, aggregatlon state, mlnera!ogy and Fe modes of occurrence. The results yielded four conceptual models far the formation of dust-emitting sediments, highlighting their physicochemical properties. These models can guide future studies in obtaining relevant information from other dese1t dust hotspots for improved dust model!ing. Prior to sampling, it is crucial to characterize the region using various approaches, including geological background, sedimentology, and remete sensing, to accurately identify dust-emitting sources. Lowlands, being the rnost emissive areas, should be prioritized, with samples taken frorn the top few centimetres of soil. The particle aggregation state can be assessed by comparing the fu!ly and minimally dispersed particle size distributions, which is critica! for desert dust emission models. Crusts, the most common sedirnents in lowlands, are typically enriched in finer minerals, precipitated minerals, and total Fe content. This detailed characterization ensures that sampling accurately represents the dust-emitting areas. The first conceptual model !acuses on mid-latitude dust hotspots (MLDH), where ephemeral lakes and floodplains serve as the primary dust sources. These areas exhibit significant dust-emitting fluxes primarily driven by aeo!ian ripples and sa!tation, breaking the crusts in lowlands, which are characterized by a high particle aggregation state, finer particle size, and elevated clay and exchangeable Fe contents comparad to highlands. A variation of this rnodel, also for MLDHs, lncludes lowland crusts with high precipitation of carbonate and salt minerals, as seen in the White Desert of Jordan. The state of aggregation in these areas depends on whether precipitation processes accumulate as cement oras single minera! particles, with total Fe content diluted by mineral precipitation. Another variant pertains to aeolian sediments deposited in lowlands from desert dust storms, such as in the Black Desert. Here, crusts form from aeolian deposition and scarce rain accumulation in small depressions within the basalt field. Mineralogical evidence indicates that these sediments originate from aeolian transport from neighbouring dust hotspots rather than local weathering substrata (basalt fields), resulting in a low to mid particle aggregation state. Dust emission in these regions is limlted due to the rugged terrain of the basalt fields and the absence of aeolian ripples. The final conceptual model pertains to a high-latitude dust hotspot (HLDH), exemplified by lceland. This model is characterized by a unique combination of volcanic geology and a glacial environment. Glacial meltwaters release large volumes of paleo-volcanic ash, stored in the glacier's ice for millennia, into the river systems. A recent volcanic eruption formed a basaltic field, acting as a natural dam and creating an epherneral lake where fine ash and sediments are deposited. The mineralogy is predorninantly volcanic glass, with a significantly higher total Fe contentlfl<ee times that of MLDHsaed high abundance of magnetite. The absence of carbonates, salts, and clays contributes to the low aggregation state of these particles. These sediments, with their fine partic!e size and low particle aggregation state, are highly prone to dust emissions by saltation and potentia!ly aerodynamic entraínment.
  

Reading date: 09/10/2024

• CAÑO PRADES, IVAN: New synthesis methodologies to develop emerging chalcogenides and chalcohalides for photovoltaic applications
  
  Author: CAÑO PRADES, IVAN
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN ELECTRONIC ENGINEERING
  Department: Department of Electronic Engineering (EEL)
  Mode: Article-based thesis
  Deposit date: 05/09/2024
  Reading date: 09/10/2024
  Reading time: 10:00
  Reading place: Defensa pública a l'Aula A0.01 del Campus Diagonal-Besòs (EEBE)
  Thesis director: SAUCEDO SILVA, EDGARDO ADEMAR | PLACIDI, MARCEL JOSE
  Committee:
       PRESIDENT: PÉREZ RODRÍGUEZ, ALEJANDRO
       SECRETARI: VOZ SANCHEZ, CRISTOBAL
       VOCAL: HOYE, ROBERT LIANQI ZHAO
  Thesis abstract: Chalcogenide materials have been central to some of the most significant events in the history of photovoltaic energy, includingthe fabrication of the first solar cell in 1883 by Charles Fritts, which was based on selenium. However, the rapid development ofcrystalline silicon starting in 1954, and the lack of knowledge on their most attractive properties, led to various chalcogenidebasedmaterials to being largely overlooked despite the technological efforts to advance solar energy from the 1960s onward.Only in the last 10 to 20 years have these materials garnered renewed interest in the scientific community, driven by newadvances in structure simulation and advanced characterization techniques in materials science.In particular, antimony and bismuth chalcogenides have garnered considerable interest, as they are constituted by earthabundantelements, which can be easily extracted from the refinement of natural ores. Also, they are mostly harmless to thehuman health and the environment, they exhibit optimal properties for photovoltaic technology (such as a high absorptioncoefficient and bandgap in the visible spectrum range), and their optical properties can be tuned through doping strategies,chemical substitution or solid solution fabrication. They also exhibit structural and electronic characteristics similar to other highperformancephotovoltaic compounds (e.g., hybrid perovskites), and their quasi-1D crystalline structure based on covalentlybonded ribbons linked by Van der Waals interactions leads to unique anisotropic properties, such as enhanced electronictransport in the direction of the covalent chains. Therefore, by adjusting the structure, crystalline orientation, and composition, it ispossible to develop new materials with a clear potential for next-generation photovoltaic technologies. Furthermore, their highabsorption coefficient and adjustable bandgap open the door to exploring new application avenues, such as flexible, semitransparentsolar cells, or compatible devices with the Internet of Things.In the context of this effort directed towards the development of chalcogenide compounds for photovoltaics, this thesis focuses onthree groups of chalcogenide and chalcohalide materials (i.e., including chalcogenide and/or halide anions), which exhibit thefollowing common features: they present properties analogous to hybrid perovskites – either structurally or electronically –, havea low-dimensional crystalline structure, are composed of abundant elements without toxicity risk, and they have been scarcelystudied, leaving many unanswered questions regarding their chemical nature, behavior as semiconductors, and performance inphotovoltaic prototypes.The work has several objectives. First, we study the effects of synthesizing Sb2Se3 under non-stoichiometric conditions, as wellas adjusting its optical properties by incorporating bismuth via thermal evaporation processes. Secondly, we develop aninnovative and versatile methodology for the fabrication of antimony chalcohalides (SbSeI and SbSeBr), based on a combinationof co-evaporation and high-temperature and high-pressure annealing, which enables the fabrication of a wide range ofcompounds that could not be effectively synthesized with the previous techniques. Finally, we investigate a new solutionprocessing methodology based on molecular precursor ink deposition which allows obtaining chalcohalide anti-perovskites(Ag3SBr and Ag3SI) at very low temperatures, opening the door for these compounds to also be manufactured using adaptableand low-cost chemical techniques. All materials have been studied using structural and optoelectronic characterizationtechniques, showing their potential as photovoltaic absorbers, and demonstrating that chalcogenides still have much to offer inthe field of solar energy.
  

• ETXANDI SANTOLAYA, MAITE: A new approach for End of Life Estimations in Electric Vehicle Batteries: Maximizing Battery Usage
  
  Author: ETXANDI SANTOLAYA, MAITE
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Normal
  Deposit date: 16/07/2024
  Reading date: 09/10/2024
  Reading time: 10:00
  Reading place: Aula Màster (Building A3) C/Jordi Girona, 1-3 08034 Barcelona
  Thesis director: CORCHERO GARCIA, CRISTINA | CANALS CASALS, LLUC
  Committee:
       PRESIDENT: BENVENISTE PÉREZ, GABRIELA
       SECRETARI: DÍAZ GONZÁLEZ, FRANCISCO
       VOCAL: REDONDO IGLESIAS, EDUARDO
  Thesis abstract: The adoption of Electric Vehicles (EVs) requires careful management of their resource-intensive batteries to make sure that the transition does not come at a high environmental cost. Technological advancements and cost reductions have led to increased battery capacities and substantial expected residual value in retired batteries, highlighting the importance of circular economy practices, such as sharing and repurposing.Effective decision-making in the battery lifecycle requires precise estimation of End of Life (EoL). Current methods use a universal criterion of 70-80% State of Health (SoH) for defining the EoL, but this overlooks the individualities of each driver and their EV battery capacity.The initial part of the thesis assesses the adequacy of the universal EoL criteria. It begins by analysing the driving performance of EVs to identify new criteria for determining the functional EoL based on specific driving needs. Subsequently, the functional EoL thresholds for various realistic use cases are obtained using driving profiles derived from a proposed synthetic driving cycle model. The findings indicate that underperformance is influenced by factors such as battery capacity, charging frequency, and driving times, highlighting the shortcomings of current EoL estimates.Recognizing the limitations of the fixed EoL criteria, the second part of the thesis introduces a novel approach for EoL estimation using the State of Function (SoF). This approach considers historical driving requirements to define individualize EoL thresholds and employs a data-driven algorithm to predict the SoH under real-world operating conditions (i.e. partial charges). Both aspects, EoL requirements and battery degradation, are included in the proposed definition of the SoF, measuring how far the battery is from underperforming.The thesis results advocate shifting from the 70-80% SoH EoL criterion to the SoF measure to improve EoL estimations. In addition, understanding the functional EoL allows exploration of alternatives like Vehicle to Grid (V2G) and second-life applications to maximize battery usage, reduce residual value when reaching the recycling stage, and minimize environmental impact.
  

• MASSAGUÉ OBRADORS, JORDI: Tendencias y dinámica de los episodios de contaminación por ozono troposférico en España.
  
  Author: MASSAGUÉ OBRADORS, JORDI
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN NATURAL RESOURCES AND THE ENVIRONMENT
  Department: Department of Mining, Industrial and ICT Engineering (EMIT)
  Mode: Article-based thesis
  Deposit date: 12/09/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: QUEROL CARCELLER, XAVIER | ESCUDERO TELLECHEA, MIGUEL
  Committee:
       PRESIDENT: DOS ANJOS ALVES, CÉLIA
       SECRETARI: GAMISANS NOGUERA, XAVIER
       VOCAL: MUÑOZ CINTAS, AMALIA
  Thesis abstract: Tropospheric ozone (O3) is a secondary gaseous photochemical pollutant with adverse effects on health, ecosystems, and materials, and it contributes to the greenhouse effect. 94% of the urban population in Europe is exposed to harmful levels of O3, especially in the south and Mediterranean countries like Spain, where regulatory values are systematically exceeded. The abatement of O3 concentrations is complex due to the nonlinear reactions between its key precursors - nitrogen oxides (NOx) and volatile organic compounds (VOCs)- , and the influence of meteorology and atmospheric transport processes at various scales. The aim of this thesis is to enhance the understanding of O3 dynamics in Spain and contribute to the future National Ozone Plan aimed at reducing its levels. This research is based on the analysis of experimental air quality and meteorological data. A regionalization of the territory has been proposed according to the severity of O3 pollution. Critical zones (hotspots) are those with the highest O3 levels and should therefore be prioritized in implementing reduction policies. These include: the Madrid basin, the north of Barcelona (NoB), the closed basin of Puertollano, the interior of the Valencian Community, and the Guadalquivir basin (GB). In these hotspots, external contributions of O3 to Spain and Europe add to the considerable O3 production generated from intense local/regional precursor emissions, causing exceedances of regulatory values. Proper management of these emissions could significantly reduce O3 levels during episodes.Two hotspots have been studied in depth: (i) the GB, where some O3 contributions have been estimated. Controlling local/regional emissions could reduce O3 levels by up to ~50% during acute episodes. (ii) Barcelona - NoB axis, where three exceptional O3 episodes in the city have been analyzed, identifying their causes (mostly common): prior accumulation of O3, weekend effect, specific meteorological conditions, with Tramontana at altitude and very high temperatures, and multiregional convergence of air masses. The evolution of O3 levels has been analyzed in three phases: before (2008- 2019), during (2020- 2021), and after (2022- 2023) the COVID-19 pandemic, due to its impact on precursor emissions. Between 2008-2019, O3 levels in the hotspots showed divergent trends. In the Madrid basin, they increased generally due to meteorology, reduced NOx emissions from road traffic, and a slight increase in VOCs, in a VOC-limited O3 formation regime. In contrast, Seville recorded decreases in O3, attributed to an atypical urban O3 formation regime (more limited by NOx). Other hotspots showed no clear trends, due to slight variations in precursor emissions and the absence of meteorological variations. During the pandemic, O3 levels decreased widely across the country, especially on the Mediterranean littoral, where for the first time regulatory values were not exceeded, due to the unprecedented reduction in precursor emissions at various scales (local, regional, European, and hemispheric), and unfavorable meteorological conditions for O3 production/accumulation. During the post-pandemic period, O3 levels increased compared to the pandemic, although they generally did not reach pre-pandemic levels, despite multiple and intense heat waves conducive to O3. In all three periods, O3 levels increased in urban areas affected by traffic emissions, indicating various causes. The results suggest a long-term convergence between O3 levels in rural and urban environments. Additionally, they highlight the importance of analyzing O3 dynamics at the local/regional scale and applying differentiated management for the various hotspots.
  

• TSIOUTI, ANDRI: Generando patrimonio a partir de los escombros. La recuperación de los paisajes mineros en España
  
  Author: TSIOUTI, ANDRI
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN URBANISM
  Department: Department of Urbanism, Territory and Landscape (DUTP)
  Mode: Normal
  Deposit date: 10/07/2024
  Reading date: 09/10/2024
  Reading time: 16:00
  Reading place: Defensa pública presencial (ETSAB. Sala de Graus)
  Thesis director: SABATE BEL, JOAQUIN | PESOA MARCILLA, MELISA
  Committee:
       PRESIDENT: LLOP TORNE, CARLOS JUAN
       SECRETARI: SALVÀ MATAS, CATALINA
       VOCAL: ARRIBAS NAVARRO, LUIS DIEGO
       VOCAL: ROMÁN LÓPEZ, MARIA EMILIA
       VOCAL: MATIAS RODRIGUEZ, ROBERTO
  Thesis abstract: The purpose of this research is to analyze the processes of reclamation of mining areas in Spain. A systematic review of the literature on this matter shows that, although there are numerous publications addressing different ways to intervene in these places, most explain the interventions in an isolated and generic manner, or as specific cases, without analyzing the entirety of the processes employed as systems of successive stages. These studies also do not pay enough attention to how changes between different stages have occurred, the factors that have influenced the transition from one trend to another, or the shift from rejection to appreciation of the mining landscapes. All of this marks the starting point of this thesis, in which we aim to uncover the processes followed in the reclamation of mining areas and to observe the changes in attitudes that have occurred from one trend to another. This would be its main contribution.By exploring the main ideas and theories that have marked the path towards the reclamation of mining spaces, we highlight how long it has taken to understand them as cultural heritage in Spain. Its recognition dates back only three or four decades, during which, however, significant advances have been achieved and unique projects have taken place.In the thesis, we demonstrate how different dimensions have been incorporated into the reclamation processes, starting from pioneering cases—preceding the more common and legally required interventions—to other reference examples. We analyze the identified processes to reveal how progress has been made, from the initial demands for adequate environmental conditions to the recognition of mining heritage and the appreciation of mining traces. We particularly focus on how the cultural dimension has been integrated into the mining reclamation processes, from the early, relatively small-scale interventions to larger projects that incorporate numerous remnants related to that activity, culminating in the creation of territorial parks. We highlight the moment when the reclamation of mining areas, previously carried out due to legal obligation or the mining companies' initiative, became a social demand aimed at fostering local development. We also consider the valorization of the geological interest of many mining sites and their reclamation as a result of that progress.We defend the representativeness of the case studies, verifying that, although they are exceptional considering the numerous abandoned mines, they end up setting a clear trend while also being representative of the reclamation processes that could be applied in similar contexts. We uncover their components and the patterns that repeat in many of them, establishing guidelines for future projects and offering lessons on the factors that ensure weaknesses do not hinder the reclamation of mining landscapes but instead promote their revaluation and use for the common good.