Theses authorised for defence
DOCTORAL DEGREE IN ARCHITECTURAL, CIVIL AND URBAN HERITAGE AND REFURBISHMENT OF EXISTING BUILDINGS
- PÉREZ SANDOVAL, MIGUEL ÁNGEL: Integración de BIM en la educación arquitectónica: Impacto del aprendizaje basado en proyectos y equipos distribuidos globalmenteAuthor: PÉREZ SANDOVAL, MIGUEL ÁNGEL
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 ARCHITECTURAL, CIVIL AND URBAN HERITAGE AND REFURBISHMENT OF EXISTING BUILDINGS
Department: Departamento de Representación Arquitectónica (RA)
Mode: Normal
Deposit date: 26/07/2024
Reading date: 22/11/2024
Reading time: 11:00
Reading place: Videoconference meet.google.com/zso-esei-wse+ Face-to-face (Room Sala de Graus. ETSAB. Main floor)
Thesis director: VALLS DALMAU, FRANCISCO | NAVARRO DELGADO, ISIDRO
Committee:
PRESIDENT: MINAYA HERNANDEZ, FERNANDO RAFAEL
SECRETARI: REDONDO DOMINGUEZ, ERNEST
VOCAL: FONSECA ESCUDERO, DAVID
Thesis abstract: This doctoral thesis delves into the user experience of the Building Information Modeling (BIM) methodology in architectural pedagogy, through four in-depth case studies. This research proposes an educational innovation approach that integrates the BIM methodology in interuniversity workshops implementing Globally Distributed Teams (GDT) and the Project Based Learning (PBL) approach, with the objective of improving the educational experience and training students for effective collaboration in Architecture. Engineering and Construction Industry (AEC).The interuniversity workshops were held with the participation of students and professors from prestigious architecture schools in Mexico and Spain: the Metropolitan Autonomous University of Azcapotzalco (UAM-Azc), the Barcelona Higher Technical School of Architecture (ETSAB) and the Higher Technical School of La Salle. Architecture (URL). Likewise, other renowned institutions such as the University of Guadalajara (UdeG) and the Universitat Politècnica de València (UPV) were integrated.For four consecutive years, participants tackled social facility design challenges, including a First Contact Family Clinic (2020), a Cultural Center (2021), an Intermediate Therapy Center for COVID-19 (2022), and a Refugee Camp . , Ukraine Crisis (2023).The research employed a mixed methodological approach that combined quantitative analysis of data collected through surveys with qualitative analysis of data derived from interviews and participant observation. With this approach, this research demonstrates that it improves the user experience through collaboration and exchange between students located in distant geographical locations, while seeking to identify best practices in the use of BIM to enrich the training of future architects. in the AEC industry. It is projected that the findings of these interuniversity workshops with GDT and PBL will be very useful for both educational institutions as a methodological example.
DOCTORAL DEGREE IN AUTOMATIC CONTROL, ROBOTICS AND VISION
- LAPLAZA GALINDO, JAVIER: Human motion and intention prediction/detection for human-robot collaborationAuthor: LAPLAZA GALINDO, JAVIER
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 AUTOMATIC CONTROL, ROBOTICS AND VISION
Department: Institute of Industrial and Control Engineering (IOC)
Mode: Normal
Deposit date: 29/10/2024
Reading date: 05/12/2024
Reading time: 11:30
Reading place: Sala Juntes Facultat de Matemàtiques i Estadística (FME), Campus Diagonal Sud, Carrer de Pau Gargallo, 14, Distrito de Les Corts, 08028 Barcelona
Thesis director: SANFELIU CORTES, ALBERTO | MORENO NOGUER, FRANCESC D'ASSIS
Committee:
PRESIDENT: GONZALEZ SABATE, JORDI
SECRETARI: ANGULO BAHON, CECILIO
VOCAL: ALAMI, RACHID
Thesis abstract: This doctoral thesis develops and evaluates advanced human motion prediction models to improve human-robot interactions in handover and harvesting tasks. The research creates three unique datasets and utilizes pose detection algorithms and RGBD cameras for 3D reconstruction of human skeletons.A deep learning model based on Attention and Graph Convolutional Networks (GCN) is proposed to enhance prediction accuracy by integrating the robot’s end effector position. The research shows greater accuracy when considering the approach and pre-contact phases separately.Additionally, by including obstacles and human intentions in the models, prediction accuracy improves further, and a user study confirms this enhances interaction quality in terms of sociability, naturalness, and comfort. The thesis also investigates body gestures as a communication channel, finding users prefer gesture-based communication over traditional methods.In summary, the research significantly contributes to human-robot interaction by providing robust datasets and advanced prediction models, enhancing the naturalness and effectiveness of collaborative tasks.
- MASIP ALVAREZ, ALBERT: Contribució a la identificació de models LTI intervalars en el domini de la freqüènciaAuthor: MASIP ALVAREZ, ALBERT
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 AUTOMATIC CONTROL, ROBOTICS AND VISION
Department: Department of Automatic Control (ESAII)
Mode: Normal
Deposit date: 27/09/2024
Reading date: 16/12/2024
Reading time: 12:00
Reading place: Sala de Videoconferències del TR1 del Campus de Terrassa, Escola Superior d'Enginyeries Industrial, Aeroespacial i Audiovisual de Terrassa (ESEIAAT-TR5) Carrer de Colom, 11, 08222 Terrassa
Thesis director: PUIG CAYUELA, VICENÇ | QUEVEDO CASIN, JOSEBA-JOKIN
Committee:
PRESIDENT: VEHI CASELLAS, JOSEP
SECRETARI: ESCOBET CANAL, TERESA
VOCAL: BONDIA COMPANY, JORGE
Thesis abstract: The main objective of this Thesis is to provide an algorithm for the robust identification of models in the form of a transfer function with interval parameters. The starting uncertain data are in the frequency domain; its representation will consist of bands of uncertainty, polygons or other flat figures in the complex plane.To reach the main objective of the work, firstly an extensive analysis of the mathematical tools and the characteristic measures of the candidate signals to excite the process is made. Different alternatives are studied to conveniently excite a process and it is verified that, whenever possible, it is necessary to apply band-limited harmonic signals to obtain information rich in spectral content. Thus, the model obtained will be able to represent the plant's behavior as faithfully as possible.Before proceeding to the robust identification itself, a historical review of nominal identification techniques is carried out. Emphasis is placed on the approach in the form of regressor of the problem. The approximation of the time delay of the plant and a method to decide the most suitable order for the model to be identified are studied.Given the inadequacy of the nominal model when looking at the data, it is proposed to incorporate uncertainty about the identified model in the form of interval parameters.The entire robustness study of the model pivots around Kharitonov's theorem, which assumes independence between the parameters of the polynomials. A chapter is dedicated to determining the frequency response of a transfer function with interval parameters based on this theorem.Within the algorithms proposed for robust identification, the work begins by extending the linear approach in parameters in the case of intervals. But this way of approaching the problem, despite presenting guarantees of convergence and optimality, shows an important fault when considering the frequency response of the identified model: it turns out to be insufficient to guarantee the inclusion of all observed data, since it omits part of the response when it establishes the restrictions of the problem.For this reason it is necessary to reformulate the problem as a non-linear optimization problem. The approach will have as its objective function to obtain the parameters of the model with the least dilation possible and that the response of the model adjusts in the most adapted way possible to the uncertain source data. The constraints will consider the property of inclusion of the data on the part of the model or vice versa. But these restrictions are given in the form of rules or in the form of a nested optimization problem. It is for this reason that it is necessary to properly condition the problem from the beginning.Since it is a non-convex optimization problem, without guarantee of a solution even though the appropriate order of the model is guessed, a previous study of stability and sensitivity is made to provide a seed and limits of the intervals to be found that ease to get the best possible solution.Throughout the Thesis there are application examples, synthetic and experimental, that show the wide scope of the proposed method and the diversity of plants on which it is applied.The thesis covers only linear, continuous and time-invariant (LTI) models. A future investigation would be to extend the results of this Thesis to the linear case with variable parameters (LPV). This would allow to put the interval coefficients of the polynomials of the identified transfer function as a function of one or several parameters that depend, for example, on the operating point of the plant.To avoid the inconvenience of the jumps caused by the restrictions in the form of rules in the optimization problem raised, it is proposed, as future work, to translate the rules as propositional logic.
- OLIVARES ALARCOS, ALBERTO: Foundations of ontology-based explainable robots Author: OLIVARES ALARCOS, ALBERTO
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 AUTOMATIC CONTROL, ROBOTICS AND VISION
Department: Institute of Robotics and Industrial Informatics (IRI)
Mode: Normal
Deposit date: 27/09/2024
Reading date: 18/12/2024
Reading time: 11:00
Reading place: Defensa pública Sala d'Actes de la Facultat de Matemàtiques i Estadística (FME), Campus Diagonal Sud, Edifici U. C. Pau Gargallo, 14 08028 Barcelona
Thesis director: ALENYÀ RIBAS, GUILLEM | FOIX SALMERON, SERGIO
Committee:
PRESIDENT: BEETZ, MICHAEL
SECRETARI: RODRIGUEZ AGUILAR, JUAN ANTONIO
VOCAL: SRIDHARAN, MOHAN
Thesis abstract: A critical challenge in the design of robots that operate while interacting with humans is to ensure mutual understanding, which contributes to build reliable human-robot interactions. It is an arduous task since interactive scenarios are often uncertain, exposing robots to exogenous situations that affect their ongoing activities. In those cases, robots shall perceive and recognize unexpected changes in the environment, represent and reason about them, and decide how to adapt to them. This will certainly modify robots' internal knowledge, and it is fair to assume that part of the new robot beliefs might be hidden from other agents such as humans. Hence, robots shall also be capable of communicating or explaining the relevant knowledge about those beliefs updates. In this context, this thesis investigates the use of ontologies as an integrative framework for the construction of robot explanations, particularly within interactive settings involving humans. To this end, the thesis starts formulating the scope of the relevant domain knowledge to conceptualize, and it continues proposing novel ontological models and methods for ontology-based robot explanation generation. The first part of the thesis discusses two main contributions: a systematic review and classification of the state-of-the-art that narrows down the target set of reality phenomena to be conceptualized, and the investigation and development of novel robot perception methods to extract from realistic robot experiences the common patterns of the target conceptualization. The second part discusses the two remaining contributions: ontological analysis and modeling of the target domain knowledge, and the design and development of algorithms to construct ontology-based robot explanations. Note that the different ontological models and algorithms were mainly validated in collaborative and adaptive robotic scenarios. However, they were conceived from a foundational perspective, and we think that their scientific value extrapolates to other application domains (e.g. assistive robotics). Overall, the scientific contributions of this thesis set a solid foundational basis for the ontology-based explainable robots domain, boosting the design of trustworthy interactive robots.
DOCTORAL DEGREE IN BIOMEDICAL ENGINEERING
- TOST ABADÍAS, ANA: Cognitive function evaluation in pediatric patients with neurodevelopmental disorders by means of EEG dataAuthor: TOST ABADÍAS, ANA
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 BIOMEDICAL ENGINEERING
Department: Department of Automatic Control (ESAII)
Mode: Article-based thesis
Deposit date: 01/10/2024
Reading date: 22/11/2024
Reading time: 11:30
Reading place: Aula 4.2, planta 4, Escola Tècnica Superior d'Enginyeria Industrial de Barcelona, Campus Diagonal Sud, Edifici PI (Pavelló I). Av. Diagonal, 647 08028 Barcelona
Thesis director: MAÑANAS VILLANUEVA, MIGUEL ANGEL | BACHILLER MATARRANZ, ALEJANDRO
Committee:
PRESIDENT: POZA CRESPO, JESÚS
SECRETARI: TAUSTE CAMPO, ADRIÁN FRANCISCO
VOCAL: SOLE CASALS, JORDI
Thesis abstract: Neurodevelopmental disorders encompass diverse conditions characterized by delays or impairments in motor, social, language, and cognitive skills. These disordersshare clinical features, making biomarker identification and validation crucial for diagnosis, outcome prediction, and treatment monitoring. Brain research seeks tounderstand normal and abnormal functions by analyzing brain activity in spatial and temporal domains, advancing our knowledge.Electroencephalography (EEG) is a key tool for studying neurodevelopmental disorders. This non-invasive technique offers excellent temporal resolution, enablingthe direct measurement of brain activity and evaluation of neurophysiological oscillations on a millisecond scale. EEG’s portability allows recordings in varioussettings, including with infants and young children, aiding in understanding typical and atypical brain development.This study focuses on EEG-based biomarkers for Rett syndrome (RTT), a rare neurodevelopmental disorder involving global psychomotor development degeneration.RTT primarily affects females due to mutations in the MECP2 gene on the X chromosome, with an occurrence rate of 1 in 10,000-15,000 newborns. Symptomsemerge between 6 and 18 months, progressing to cause developmental delays, seizures, coordination and movement difficulties, and social and communicationimpairments.Assessing cognitive and social aspects in RTT patients is challenging due to the absence of speech, declining purposeful hand movements, and emerging autismsymptoms. However, research shows that RTT patients can communicate through pre-intentional methods, with eye gaze being particularly effective when usingeye-tracking technology. This allows for quantifiable assessments of cognitive and social aspects.The study investigated neural responses in RTT patients during cognitive tasks using eye-tracking and wireless EEG to measure brain activity. The goal was toenhance neuropsychological abilities and provide cognitive training to improve communication deficits. However, EEG registration in awake pediatric patients withintellectual and motor disabilities is challenging due to artifacts from uncontrolled movements and muscle activity, necessitating the development of an optimalartifact rejection method for reliable results.The thesis developed an artifact rejection strategy effective across all signal types, exploring energy-based and distribution-based methods. Performance validationinvolved classifying data by variability and using density estimators for visualization and probabilistic categorization.The second objective was to assess brain activation changes from cognitive training over four days using spectral EEG analysis during resting state with eyes open(EO-RS), active training (AT), and passive training (PT). This aimed to understand how cognitive training influences brain activity patterns over time and betweenstates.The third objective was to evaluate connectivity during a single session, comparing AT and PT with EO-RS. Connectivity was assessed using magnitude squaredcoherence (MSC) and cross mutual information function (CMIF) to determine whether cognitive stimulation improves brain connectivity and information flow, aimingto identify the most effective protocol and provide insights into RTT pathophysiology and therapeutic interventions.In conclusion, this thesis advances the understanding of RTT and its therapeutic interventions. The effective artifact rejection strategy addressed challenges in EEGdata analysis for pediatric patients with neurodevelopmental and motor disorders. Findings from spectral and connectivity analyses showed cognitive trainingbenefits, including shifts in power to fast frequency bands, increased connectivity, and reduced brain asymmetry. These insights support developing targetedinterventions and therapies for improved outcomes in RTT.
DOCTORAL DEGREE IN BUSINESS ADMINISTRATION AND MANAGEMENT
- BARRAJÓN RASTROLLO, JOSE LUIS: Navigating Organizational Change for Successful Implementation of HR AnalyticsAuthor: BARRAJÓN RASTROLLO, JOSE LUIS
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 BUSINESS ADMINISTRATION AND MANAGEMENT
Department: Department of Management (OE)
Mode: Normal
Deposit date: 19/09/2024
Reading date: 13/12/2024
Reading time: 13:00
Reading place: Defensa pública Sala Juntes, planta 1, FIB - UPC
Thesis director: FERNANDEZ ALARCON, VICENÇ | GALLARDO GALLARDO, EVA
Committee:
PRESIDENT: MARIN GARCIA, JUAN A.
SECRETARI: PONS PEREGORT, OLGA
VOCAL: ORTIZ DE URBINA CRIADO, MARTA
Thesis abstract: Context: Numerous studies affirm the positive impact of Human Resources Analytics (HRA) on gaining a competitive edge and enhancing Human Resources (HR) strategic role therefore given the importance of knowing how to implement an HRA function in organizations successfully, this Ph.D. thesis brings relevant insights of the most critical variables, and the barriers to be faced during this process so that future researchers and practitioners have the enough knowledge and tools to address it with success.Purpose: The Ph.D. thesis is divided into two interrelated purposes: (1) identifying the most crucial factors through which organizations base their HRA implementation and (2) the learning barriers to face during the organizational change that suppose implementing those factors to become a data-driven decision-making organization.Method: For the culmination of both purposes, we have conducted an inductive/explorative study using semi-structured interviews as the qualitative data collection method. In this case, the sample consists of ten managers, seven HRA function leaders, and three from HR departments who had carried out analytics projects. Those ten leaders work for ten different organizations in distinct sectors and across varying levels of analytical maturity. We have based on a couple of frameworks, one of organizational learning and another of HRA to design and create our own to guide the research.Results: Through empirical qualitative research, we obtained the five key HRA factors highlighted in the literature: Data, Technology Support, Culture, People and Project Design. Additionally, we considered the analytical maturity level of our organization's sample and related to this, the results show that Data quality and accessibility are crucial in descriptive and predictive stages. On the contrary, prescriptive organizations seem to be more focused on Technology, to support advanced analytical models. As far as organizational change is concerned, our results show that the intensity of the learning barriers in HRA decreases as the organizations increase their analytical maturity level. Besides, communication problems seem to be in the descriptive organizations, especially with the Data and Technology departments and the management. On the other hand, in predictive organizations, HR and/or HRA departments seem to lack autonomy in accessing the Data, building their teams, and choosing the technology they need to mature the function. Finally, other factors, such as ethics, budget, and trust in the HR function, were shown in the results.Conclusions / Implications: This allows researchers and practitioners to design and implement an HRA function supported by a framework that guarantees success in the process.Originality: This Ph.D. thesis extends existing theory about HRA success factors (SSFF), as well as organizational learning, developing a new model including both disciplines for implementing HRA function in organizations successfully.
- CARBONELL LAUNOIS, NICOLAS: ENTREPRENDRE AU BURKINA FASO : Quelles sont les contraintes au développement des entreprises et les facteurs de succès pour entreprendre au Burkina Faso, un pays pauvre et enclavé au coeur de l’Afrique?Author: CARBONELL LAUNOIS, NICOLAS
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 BUSINESS ADMINISTRATION AND MANAGEMENT
Department: Department of Management (OE)
Mode: Normal
Deposit date: 18/10/2024
Reading date: 17/12/2024
Reading time: 12:00
Reading place: Seminari 1- DOE, planta 7 de l' ETSEIB- UPC - Avda. Diagonal, 647, Barcelona
Thesis director: VAN WUNNIK, LUCAS PHILIPPE
Committee:
PRESIDENT: SIRI, ALAIN
SECRETARI: GRIMALDI, DIDIER CAMILLE
VOCAL: CHAPUS, QUENTIN
Thesis abstract: This thesis examines the constraints to business development and identifies the key success factors for entrepreneurship in Burkina Faso, a landlocked and poor country located in the heart of Africa. The work is based on an in-depth analysis of the geographical, historical, institutional and cultural obstacles that hinder the country's economic development and explores how some entrepreneurs manage to overcome these difficulties.The thesis develops a typology of development obstacles, classified according to their depth: deep obstacles (geographical and historical), intermediate obstacles (cultural and technological) and immediate obstacles (governance and access to finance). These elements are confronted with the strategies of Burkinabe entrepreneurs who have been able to grow their businesses in these difficult conditions.The theoretical study identifies five key success factors contributing to the success of businesses in Burkina Faso: the educational level of entrepreneurs, their entrepreneurial leadership, their strategic positioning, organizational efficiency, and their ability to adapt to the environment. To determine the relative importance of success factors and business performance, surveys and accounting analyses will be conducted.From the discussion of the results of this research, recommendations arise for entrepreneurs, policy makers and researchers to support business development in Burkina Faso.
- RICO FLOR, CRISTINA: Un planteamiento metodológico acerca de la mejora en el sector público del Principado de Andorra. La tramitación administrativaAuthor: RICO FLOR, CRISTINA
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 BUSINESS ADMINISTRATION AND MANAGEMENT
Department: Department of Management (OE)
Mode: Normal
Deposit date: 27/09/2024
Reading date: 28/11/2024
Reading time: 11:30
Reading place: Seminari I - Dept. Organitació d'Empreses, planta 7 - ETSEIB- UPC - Avda. Diagonal, 647, Barcelona
Thesis director: CAÑABATE CARMONA, ANTONIO
Committee:
PRESIDENT: PEÑA LÓPEZ, ISMAEL
SECRETARI: COLL BERTRAN, JOSEP
VOCAL: ALET VILAGINES, JOSEP
Thesis abstract: Administrative procedures are the most common form of interaction between citizens and the Administration, serving as the mechanism through which public services are provided. The aim of this thesis is to demonstrate that administrative procedures can be improved by applying process management and game theory.The research question posed is: Can administrative procedures be improved through the application of process management and the definition of a Nash equilibrium for the strategies that the Administered and the Administration can follow? As we will see, the application of the proposed methodology allows us to identify significant improvement opportunities that will be useful for enhancing administrative procedures. From this experience, fundamental knowledge will be obtained that will serve both for its application in future projects to improve processes in other areas of this Administration, as well as in other public administrations.The research has three objectives: 1) To identify which aspects of administrative procedures could be improved to increase user satisfaction, 2) To define the best strategy for the citizen to follow to successfully complete the procedure, and 3) To define the best strategy for the Administration to follow to increase the satisfaction of users of the service, with the priority of optimizing the management of public resources.The work is structured into two parts, each applying a different methodology. This approach to research is based on current methodological trends used in the evaluation of public policies.In the first part of the research, improvement in the service provider is addressed through the application of Process Management for Public Administration (PMPA). This methodology has been specifically created to design improvement processes in Public Administration.The second part of the thesis focuses on considering administrative procedures as a strategic situation involving two agents: the Administration (A) and the Administered (U). Based on this consideration, the following hypothesis was defined: “Given the strategic situation between the Administration and the Administered, which involves carrying out the administrative procedure, the optimal solution will be reached when neither the Administration nor the Administered have reasons to change their strategy, finding themselves in a state of equilibrium.”The identification of the improvement is resolved through the development of a mathematical model obtained from the application of game theory. This model serves to identify a Nash equilibrium and analyze how this equilibrium point varies depending on the different strategies that the Administration and the Administered can adopt when facing administrative procedures.The results of the first part of the research allow for the identification of specific aspects of the processes that can be improved and how to do so. In the second part, identifying the strategies that lead to a Nash equilibrium allows for specifying what the user should do when facing administrative procedures to achieve a satisfactory result and what is the best strategy for the Administration to provide the best service to citizens, considering the limitations of its resources.The research focuses on improving administrative procedures within the framework of a simplified administration, such as that of Andorra, and in the realm of public policy evaluation, which is increasingly becoming a key aspect for public managers.
DOCTORAL DEGREE IN CHEMICAL PROCESS ENGINEERING
- ARMENGOL PROFITÓS, MARINA: Cobalt-Ruthenium Bimetallic Catalysts for Dry Reforming of MethaneAuthor: ARMENGOL PROFITÓS, MARINA
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 CHEMICAL PROCESS ENGINEERING
Department: Department of Chemical Engineering (EQ)
Mode: Normal
Deposit date: 16/09/2024
Reading date: 03/12/2024
Reading time: 11:30
Reading place: EEBE - Sala Polivalent - Edifici A - Campus Diagonal-Besòs
Thesis director: LLORCA PIQUE, JORDI | JIMÉNEZ DIVINS, NÚRIA
Committee:
PRESIDENT: MEDINA CABELLO, FRANCISCO
SECRETARI: CABOT CODINA, ANDREU
VOCAL: VELASCO VÉLEZ, JUAN JESÚS
Thesis abstract: The processes used nowadays for hydrogen and syngas production require more sustainable alternatives to advance in the necessary decarbonisation to fight against climate crisis. Currently, the main process is methane steam reforming (MSR) using natural gas. In this thesis, the use of dry reforming of methane (DRM) is proposed as a method of producing syngas. DRM is an attractive alternative since the two reactants, methane and carbon dioxide, are gases with a high global warming potential (GWP). Moreover, they are found together in the biogas resulting from the anaerobic digestion of organic matter. In the actual state-of-the-art, Ni catalysts supported on a wide range of metal oxides have been extensively studied. However, the main disadvantage is the accumulation of carbon that causes deactivation.In Chapter 4, the application of CoRu bimetallic catalysts supported on CeO2 has been studied. The catalysts have been prepared by conventional incipient wetness impregnation and by mechanochemical methods. A screening of catalytic activity has been conducted, and in-situ characterisation (NAP-XPS and XRD) has been used to get insight into the nature and behaviour of the catalytic active sites. It has been observed how the addition of ruthenium directly impacts the reducibility of cobalt species and results in smaller nanoparticles, as demonstrated by temperature-programmed reduction (H2-TPR) and XRD, respectively. The results of NAP-XPS show how ruthenium is able to modify the metal-support interaction, evidenced by a greater Ce3+/Ce ratio in the bimetallic samples. The synthesis method influences the dispersion of Co and Ru on the surface; NAP-XPS data suggested a higher Ru concentration on the surface of the bimetallic ball-milled samples, indicating the formation of small Ru clusters during milling, as confirmed by TEM analyses. Samples prepared by mechanochemistry, both mono- and bimetallic, have higher activity and stability than those synthesised by the conventional impregnation method, achieving higher CH4 and CO2 conversions. CoRu/CeO2-BM catalyst turns out as a stable catalyst for 24 hours at 700 C and with an average H2/CO ratio close to 1.In Chapter 5, the application of the same CoRu formulation supported on a Mg-Al-O mixed oxide has been studied. For these catalysts, the effect of Ru addition and the use of different precursors has also been studied, observing an effect on the catalytic activity and stability related to a synergy between Co and Ru. Through a "Design of Experiments" approach, the impact of various parameters of mechanochemical synthesis, such as milling frequency, milling time, and precursor addition order, has been studied. It should be highlighted that the samples synthesised by mechanochemistry show a lower amount of carbon deposits, which is ascribed to the particular architecture of the catalytic active sites.Finally, in Chapter 6, characterisation under operating conditions (X-ray absorption spectroscopy and X-ray diffraction) of the main samples synthesised in the previous chapter is performed. In addition to studying dry methane reforming, a small amount of water vapour is added to the reaction to study the combined reforming of methane (CRM), where steam reforming and dry reforming occur simultaneously. It is also observed that in CRM the carbon deposition in samples prepared by mechanochemical methods is substantially lower than those synthesised by conventional impregnation.
- LECHTENBERG, FABIAN: Multi-actor multi-criteria decision-making methods and tools for the implementation of industrial symbiosis and circular economy solutions in the process industryAuthor: LECHTENBERG, FABIAN
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 CHEMICAL PROCESS ENGINEERING
Department: Department of Chemical Engineering (EQ)
Mode: Normal
Deposit date: 01/10/2024
Reading date: 26/11/2024
Reading time: 11:00
Reading place: Defensa pública EEBE, Sala Polivalent, Ed. I, I0.1, Campus Diagonal - Besós.
Thesis director: GRAELLS SOBRE, MOISES | ESPUÑA CAMARASA, ANTONIO
Committee:
PRESIDENT: CABALLERO SUÁREZ, JOSÉ ANTONIO
SECRETARI: MONTASTRUC, LUDOVIC
VOCAL NO PRESENCIAL: LEONARD, GRÉGOIRE
Thesis abstract: The quest for sustainable development is both urgent and complex. Paradigms like circular economy (CE) and industrial symbiosis (IS) aim to address this challenge by promoting strategies to achieve a more efficient use of available resources and a reduction of generated waste. However, the implementation of these paradigms faces significant practical challenges that hinder their widespread application. Despite the availability of process integration (PI) methods and tools to identify opportunities for sharing resources and closing material loops in the process industry, and the growing computational power to handle increasingly complex problems, the practical challenge remains to quantitatively, fairly, and transparently demonstrate that the proposed solutions satisfy the objectives of all decision-makers involved.Driven by this challenge, this Thesis aims to bridge the gap by developing frameworks that facilitate multi-actor multi-criteria decision-making. To achieve this, appropriate methods from game theory (GT) are identified to address the multi-actor problem, evaluating the alternatives based on Life Cycle Assessment (LCA) that allows for obtaining quantitative, comparable, and transparent indicators for the multi-criteria problem. Focusing on the process industry, all developed solution methods leverage process systems concepts and mathematical programming. In the first part of this Thesis, GT is utilized as a tool to find solutions that are fair and acceptable for all actors involved. To that end, cooperative profit allocation approaches are applied to PI problems, which have been designed using a proposed framework to reach targeted benefits (economic and environmental) through the introduction of waste-to-resource technologies. Moreover, a Stackelberg competition based framework for the identification of stable outcomes of non-cooperative bargaining between the actors in waste-to-resource pathways, in the absence of a regulatory authority, is proposed and applied a plastic waste recycling case. The second part employs LCA as a tool to quantify the environmental benefits of implementing CE and IS solutions, as a procedure to systematically consider interlinked phenomena such as burden-shifting. Furthermore, this Thesis advances life cycle optimization (LCO) by integrating mathematical programming with LCA to leverage extensive data from commercial Life Cycle Inventory (LCI) databases. Practical contributions include the development of the ``Python-based User-defined Lifecycle Product Optimization'' (PULPO) method, which exploits LCI databases to globally evaluate the individual decisions of the involved processes and their interdependencies. This approach allows the consideration of global supply chain targets in the decision-making of specific links in the chain.The third part synthesizes the insights and approaches developed in the previous two parts and proposes the cooperative PI-MAMCA framework, which includes quantitative procedures for evaluating the stability in the allocation of benefits, based on previously established approaches for multi-actor multi-criteria decision-making. For the first time, simultaneous allocation of various benefits among multiple actors is proposed, demonstrating that, even when considering multiple criteria, fair and acceptable solutions exist.
DOCTORAL DEGREE IN CIVIL ENGINEERING
- GARRIDO SALSAS, FRANCISCO JAVIER: THE IMPACTS OF MAIN TRENDS ON THE PORT SECTOR. EVOLUTION TOWARDS A NEW GENERATION OF GREEN AND DIGITAL PORTSAuthor: GARRIDO SALSAS, FRANCISCO JAVIER
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 CIVIL ENGINEERING
Department: Barcelona School of Civil Engineering (ETSECCPB)
Mode: Normal
Deposit date: 27/09/2024
Reading date: 02/12/2024
Reading time: 11:00
Reading place: ETSECCPB, Sala Tesines C1-002 (C/Jordi Girona 1-3, mòdul C1, Campus Nord, Barcelona).
Thesis director: SAURI MARCHAN, SERGI
Committee:
PRESIDENT: TRUJILLO CASTELLANO, LOURDES
SECRETARI: CAMPOS CACHEDA, JOSÉ MAGÍN
VOCAL: CAMARERO ORIVE, ALBERTO
Thesis abstract: Trends in logistics and more broadly across technology and energy are resulting in changes on the traditional business models and roles of ports. Since the port ecosystem is going to be considerably different in the following two decades, decision-makers need to be aware about these trends to prioritize investments and build new and dynamic strategic masterplans. This thesis seeks to analyze some current trends impacting on ports and analyze the changes on their roles to define long-term strategy. The results of this thesis will contribute to the state of the art of Ports of the Future by identifying the main trends impacting on ports in the long term (2040). The impacts are identified by means of the Delphi method process within the Port Community of Barcelona. The research allowed to identify which are the key drivers that are going to transform ports: green measures to decarbonize maritime transport and supply chains; circular economy hubs to produce or customize on site and on demand products in port areas; new physical and digital infrastructures for automated and connected vehicles and port terminals; and finally, a fully digitalization to offer new services (track and trace, call optimization, etc.) as well as an optimized supply chain oriented to offer resiliency for the hinterland clients of the ports. These trends will change the long-term port business ecosystem. The research uses Business Canvas Model methodology to identify the future port management dynamics, role and strategy. The results outline conceptual actions to be considered and introduced in port planning to ensure its sustainable growth in harmony with their nearby societies. The conclusions taken based on the case study of the Port of Barcelona are extended to other European ports. The thesis studies the evolution of the ship size, which is a relevant factor in order to plan the investments needed in port infrastructure. The analysis is focused on the container segment which is one of the most relevant in maritime trade. Since the container ship was born, we have seen an impressive increase in order to get advantage of the economies of scale. In the last two decades, the capacity of vessels has been trebled. Despite the exponential growth experienced in this sector, individuals question if it is possible to reach a peak capacity, as has occurred with bulk cargo vessels and, recently, aircraft. This thesis aims to predict the possible size and dimensions of a new generation of mega container ships. Based on economy of scale, port infrastructure, demand and environmental trends and naval design criteria the limit ship size has been estimated. The results suggest that it is still possible additional slight increases of the ship size. This thesis allows Port Authorities to understand the needs of shipping container industry to plan the expansion and investment necessary in their ports.In terms of social sustainability, the research explores how is going to impact the identified trends in the human capital of ports, focusing on the introduction of new technologies. Among others, ICT, cloud technology, 5G, automation, augmented reality, artificial intelligence, block chain and Big Data Analytics are going to conduct several major changes in the port job market. The thesis analyses the impacts of these changes on the capacities and training of port personnel based on questionnaires and interviews to relevant ports of different continents. Finally, in terms of environmental sustainability, the thesis explores measures for decarbonization of ports, due to the fact that it is expected to be a key strategic factor. In this dimension, the thesis focusses on one of the measures with higher impact on reduction of GHG emissions and air pollution, which is the On Shore Power supply. presenting the current state of the art of OPS in ports and the main challenges and barriers in the future. The analysis is linked with the Energy Transition strategy of ports.
- MALIKOSKI VIEIRA, LUAN: Low-order face-based approaches for incompressible computational fluid dynamicsAuthor: MALIKOSKI VIEIRA, LUAN
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 CIVIL ENGINEERING
Department: Barcelona School of Civil Engineering (ETSECCPB)
Mode: Change of supervisor
Deposit date: 27/09/2024
Reading date: 29/11/2024
Reading time: 15:30
Reading place: Defensa pública ETSECCPB, Sala Tesines C1-002 (C/Jordi Girona 1-3, mòdul C1, Campus Nord, Barcelona)
Thesis director: HUERTA CEREZUELA, ANTONIO | GIACOMINI, MATTEO | SEVILLA CÁRDENAS, RUBÉN
Committee:
PRESIDENT: HASSAN, OUBAY
SECRETARI: NOGUEIRA GAREA, XESÚS ANTÓN
VOCAL: CARDIFF, PHILIP
Thesis abstract: The fast and accurate simulation of laminar and turbulent incompressible flows is crucial in science and engineering. Low-order numerical strategies, particularly finite-volume (FV) methods based on cell-centred and vertex-centred approaches, remain essential in CFD, especially in industrial settings, due to their favourable trade-off between computational cost and accuracy. However, these methods face challenges such as stabilising convective-dominated flows, handling velocity-pressure coupling, and managing numerical flux reconstruction on distorted and stretched grids. The face-centred finite volume (FCFV) method emerges as an alternative to standard FV methods. Derived from a mixed formulation of the discontinuous Galerkin method, FCFV avoids flux reconstruction at cell faces, making its accuracy and convergence nearly insensitive to grid quality. It also satisfies the Ladyzhenskaya-Babuška-Brezzi (LBB) condition without special treatment for velocity-pressure coupling. This work showcases the FCFV method for simulating laminar and turbulent incompressible flows for the first time. The formulation is based on the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the negative Spalart-Allmaras (SA) model. Three new convective stabilisations inspired by Riemann solvers are proposed, along with monolithic and staggered solution strategies for the RANS-SA system and two relaxation strategies for pseudo-time marching. A new hybrid pressure FCFV formulation is also introduced to improve the FCFV accuracy in laminar flow simulations by enriching the pressure space through relaxed compressibility conditions. Both FCFV and hybrid pressure FCFV achieve first-order convergence of velocity, velocity gradient tensor, and pressure, accurately predicting engineering quantities such as drag and lift on structured and unstructured meshes. By avoiding gradient reconstruction, these methods are less sensitive to mesh quality, even on highly distorted grids. Numerical benchmarks for laminar and turbulent, steady and transient cases assess the performance, accuracy, and robustness of the proposed methodologies. Implemented in Fortran 90, these methods lay the foundation for the integration of FCFV techniques within the CFD community. The work concludes with a detailed discussion of the Fortran 90 FCFV code implementation.
- SANZ RAMOS, MARCOS: Numerical modelling of non-Newtonian shallow flowsAuthor: SANZ RAMOS, MARCOS
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 CIVIL ENGINEERING
Department: Barcelona School of Civil Engineering (ETSECCPB)
Mode: Article-based thesis
Deposit date: 30/09/2024
Reading date: 18/12/2024
Reading time: 11:30
Reading place: Defensa pública ETSECCPB, Sala Tesines C1-002 (C/Jordi Girona 1-3, mòdul C1, Campus Nord, Barcelona).
Thesis director: BLADE CASTELLET, ERNEST
Committee:
PRESIDENT: SALAZAR GONZÁLEZ, FERNANDO
SECRETARI: SANCHEZ JUNY, MARTI
VOCAL: LÓPEZ GÓMEZ, DAVID
Thesis abstract: Numerical modelling of natural phenomena, particularly weather-related which are the 90 % of global disasters, is essential to analyse and predict hazardous situations for the people, the economy and the environment. The evolution of these numerical tool, from simple one-dimensional to complex three-dimensional models, to simulate hydrological hazards like floods, mass movements, and avalanches is challenging, especially those in which the fluid can be characterized as non–Newtonian flows.This PhD thesis focusses on the extension of Iber, a depth-averaged two-dimensional hydrodynamic numerical tool, to simulate non–Newtonian shallow flows. To that end, a particular numerical scheme based on an upwind discretisation to ensure for the non–velocity-dependent terms of the shear stresses has been developed to counterbalance the pressure forces. This ensures the stop of the fluid according to the rheological properties of the fluid, even in steep slopes and complex geometries. The code besides being validated and applied in theoretical, analytical, and in common and non–common non–Newtonian shallow flows in real situations, it has been fully integrated in the graphical user interface of Iber. This facilitates the model build-up, setup and results visualization converting the new code in a software suite fully operational for all practitioners.
DOCTORAL DEGREE IN COMPUTATIONAL AND APPLIED PHYSICS
- DUQUE GIJON, MARIA: Experimental study of the coherence of the light emitted by a semiconductor laser with optical feedbackAuthor: DUQUE GIJON, MARIA
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 COMPUTATIONAL AND APPLIED PHYSICS
Department: Department of Physics (FIS)
Mode: Normal
Deposit date: 27/09/2024
Reading date: 05/12/2024
Reading time: 11:00
Reading place: Sala Conferencias del TR5, c/ Colom 11, Campus Terrassa
Thesis director: MASOLLER, CRISTINA | TIANA ALSINA, JORDI
Committee:
PRESIDENT: CORNELLES SORIANO, MIGUEL
SECRETARI: VILASECA RICART, MERITXELL
VOCAL: HONG, YANHUA
Thesis abstract: Semiconductor lasers are part of our daily lives, finding applications in telecommunications, sensing, metrology, and biomedicine due to their compact size, efficiency, and versatility. This thesis explores how optical feedback influences the temporal and spatial coherence of semiconductor lasers through a technique based on random intensity patterns, i.e., speckle. Optical feedback involves reinjecting part of the emitted laser light through an external reflector, inducing various nonlinear dynamics operating regimes. While much research has focused on optical feedback's effects on temporal coherence, its impact on spatial coherence is less studied. This thesis proposes the speckle contrast analysis to study the coherence of semiconductor laser light under optical feedback. Speckle patterns arise from the interference of coherent light when it propagates through a diffusive medium. This technique enables the quantification of the coherence of the light providing, valuable insights into the spatial coherence of laser light. High speckle contrast patterns reveal valuable information about both the laser light and the diffusive medium. However, speckle can degrade image quality in imaging applications, requiring speckle mitigation. The thesis aims to study how optical feedback affects the coherence of the light emitted by a semiconductor laser, with the particular goal of identifying conditions where feedback reduces the light coherence and, consequently, the speckle contrast.The first part of this thesis investigates the emergence and evolution of coherence during the laser turn-on transition under different optical feedback scenarios with respect to the non feedback scenario, using a mirror and a diffractive grating as reflectors, and using a multimode fiber as a diffusive medium.The second part proposes a procedure to differentiate between temporal and spatial coherence using speckle pattern analysis with three different diffusive mediums: multimode fiber, multimode fiber and a diffuser, and single-mode fiber and a diffuser. By analyzing speckle contrast and relating it with optical spectrum measurements, we reveal the evolution of the coherence in a solitary and optically fed back semiconductor laser across a huge range of pump currents, highlighting the difference between temporal and spatial coherence. Complementary to speckle contrast technique we have made use of the spatial entropy measure to unveil nonlinear spatial correlations between pixel values of speckle images.This thesis also investigates the impact of sinusoidal modulation in the pump current on the coherence of semiconductor lasers with optical feedback. The modulation amplitude and frequency play a crucial role in influencing coherence. The goal is to identify the optimal modulation conditions under which a fed back semiconductor laser emits light with lower spatial and temporal coherence compared to scenarios without modulation.Finally, this thesis includes a chapter on the impact of optical injection on the timing jitter of a semiconductor laser. Timing jitter refers to the variability in the timing of emitted light pulses from the semiconductor laser, which can significantly impact the precision of optical systems, as the optical analog-to-digital converters.This study was carried out at the Photonics Laboratory at IFCA under the supervision of Dr. Ana Quirce, as a secondment.This thesis is devoted to an experimental study of the effects of Optical feedback or optical injection on the temporal and spatial characteristics of the output emission of semiconductor lasers.
- ZENG, MING: Barocaloric and multicaloric effects under hydrostatic pressure and electric fieldAuthor: ZENG, MING
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 COMPUTATIONAL AND APPLIED PHYSICS
Department: Department of Physics (FIS)
Mode: Normal
Deposit date: 05/11/2024
Reading date: 04/12/2024
Reading time: 09:45
Reading place: Aula A2.1- Escola d'Enginyeria de Barcelona Est. (EEBE)
Thesis director: LLOVERAS MUNTANE, POL MARCEL | TAMARIT MUR, JOSE LUIS
Committee:
PRESIDENT: NATAF, GUILLAUME
SECRETARI: ROMANINI, MICHELA
VOCAL NO PRESENCIAL: LI, JUNNING
Thesis abstract: At present, HFC refrigerants with a global warming potential of thousands of times that of CO2, are widely used in air conditioners and, refrigerators. Due to lack of maintenance and poor management, and low or moderate efficiencies, cooling devices contribute to approximately 8% of total greenhouse gas emissions. Given the increasing global warming, it is urgent to find new cooling technologies with low carbon emissions. Cooling methods based on solid-state caloric effects (adiabatic temperature changes ∆T and isothermal entropy changes ∆S) driven by external fields have been proposed as an environmentally friendly alternative to today's gas compression equipment. This thesis focus on caloric effects driven by hydrostatic pressure (barocaloric, BC) and/or electric field (electrocaloric, EC) near first-order phase transitions. In particular, BC effects have been investigated in different material families: Inorganic salts, Mn-based antiperovskites, superionic plastic crystals, and melting of stearic acid encapsulated in metal–organic frameworks (MOFs). Multicaloric effects were also investigated under simultaneous application of pressure and electric field on Lead Scandium Tantalate (PbSc0.5Ta0.5O3, PST). For this purpose, standard and modulated differential scanning calorimetry, and differential thermal analysis under different applied pressure and/or electric field were performed on the mentioned materials. The obtained data were combined with temperature-dependent volume data to construct the isofield entropy curves from which the caloric effects were calculated using the quasi-direct method. Concerning antiperovskite manganese nitrides: Mn3Cu1 – xSnxN, giant inverse BC effects were obtained. Interestingly, all these samples exhibit reversible|∆S| > 20 J K−1 kg−1 at pressures below 100 MPa thanks to a hysteresis lower than 1 K, which is minimized at the equiatomic composition x=0.5. Concerning LiCB11H12, this compound exhibits a high-temperature phase that combines superionic conductivity and orientational molecular disorder which appears above a phase transition with colossal latent heat. In that case, we obtained outstanding conventional reversible |∆S| 200 J K−1 kg−1 and |∆T| 10 K, respectively ∆p 100 MPa, which increase up to |∆S| 280 J K−1 kg−1 and |∆T| 32 K, respectively, under the applied pressure of only ∆p 230 MPa. Concerning MIL−101 (Cr)−NH2+x% stearic acid (SA) system, that with x = 80% SA displays |∆T| 25 K and |∆S| 550 J K−1 kg−1 under ∆p 200 MPa. These results suggest that MOFs can be used as suitable solid framework for encapsulation of non-solid high-performance BC materials. Finally, the multicaloric effects in the prototypical ferroelectric PST have also been studied. Unprecedented calorimetry experiments under simultaneous electric fields E up to around 7 kV cm−1 and hydrostatic pressures p up to 400 MPa were conducted across the ferroelectric transition on PST. The so far unexplored 3-dimensional phase diagram T(p,E) was obtained and analyzed. It was demonstrated that multicaloric effects may provide opportunities that cannot be achieved by monocaloric effects, such as tuning or expansion of temperature ranges and efficiency improvement. This research has demonstrated the feasibility, novelty, and impact of multicaloric effects under p and E, thus opening up a new area of caloric effects that should provide new physical insights on the wide family of ferroelectrics.
DOCTORAL DEGREE IN CONSTRUCTION ENGINEERING
- MENDUIÑA MONTERO, RAUL: Estudio teórico y experimental del refuerzo mediante recrecido de encepados rígidos de hormigón armadoAuthor: MENDUIÑA MONTERO, RAUL
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 CONSTRUCTION ENGINEERING
Department: Department of Civil and Environmental Engineering (DECA)
Mode: Normal
Deposit date: 25/10/2024
Reading date: 16/12/2024
Reading time: 11:30
Reading place: ETSECCPB UPC- Aula C1002 - C/Jordi Girona, 1-3 08034 Barcelona
Thesis director: BAIRÁN GARCÍA, JESÚS MIGUEL | MARI BERNAT, ANTONIO RICARDO
Committee:
PRESIDENT: TORRES LLINAS, LLUÍS
SECRETARI: OLLER IBARS, EVA MARIA
VOCAL: FERNANDEZ PEREZ, IGNASI
Thesis abstract: The need to strengthen foundations in existing structures has become increasingly important, driven by the aging of constructions and the growing demand for enhanced structural capacity, whether due to changes in use or updates to regulatory standards. In the case of rigid RC foundations, these often behave as D-regions, areas where stress and deformations do not follow a linear pattern and require specialized design approaches. While numerous studies have focused on the reinforcement of B-regions, research addressing the behavior of D-regions, such as rigid foundations, remains limited. This thesis addresses this gap by analyzing the behavior and reinforcement techniques through the enlargement of rigid reinforced concrete pile caps, a solution that increases their structural capacity. Special emphasis is made on the application of the Strut-and-Tie Method (STM), an approach particularly suited for D-regions, as it simplifies the non-linear behavior of stresses in these areas, facilitating the understanding of the structural mechanisms involved.The research combines a comprehensive literature review with an experimental campaign, in which reinforcement of rigid RC pile caps through enlargement was evaluated. The experimental tests and Non-Linear Finite Element Analysis (NLFEA) helped study the structural behavior of the pile caps in different configurations. The analysis of the results shows that enlargement is an effective technique to improve the structural capacity of foundations, although its success depends on factors such as the quality of the joints between the new and existing concrete and, to a lesser extent, the arrangement of secondary reinforcement. Additionally, the behavior in the Serviceability Limit State (SLS) was analyzed, and strut-and-tie models were proposed, with concrete ties whose tension varies with the evolution of crack widths. These models are capable of coherently explaining the behavior observed experimentally across the entire load range.Following the presentation of the experimental results, different design methodologies are compared, and the use of STM for reinforced pile caps is proposed, with a particular focus on verifying the struts crossing the joints between the original and enlarged sections. The findings are not only applicable to various structural scenarios but also establish a solid foundation for future research on the reinforcement of D-regions, making a significant contribution to the preservation and enhancement of existing structures.
DOCTORAL DEGREE IN ELECTRICAL ENGINEERING
- DADJO TAVAKOLI, SAMAN: Control Design for Converters in Modern Power SystemAuthor: DADJO TAVAKOLI, SAMAN
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 ELECTRICAL ENGINEERING
Department: Department of Electrical Engineering (DEE)
Mode: Normal
Deposit date: 25/09/2024
Reading date: 22/11/2024
Reading time: 11:00
Reading place: Aula 28.8 - ETSEIB- UPC - Avda. Diagonal, 647, Barcelona
Thesis director: GOMIS BELLMUNT, ORIOL | PRIETO ARAUJO, EDUARDO
Committee:
PRESIDENT: WANG, XIONGFEI
SECRETARI: RENEDO ANGLADA, FRANCISCO JAVIER
VOCAL: LINDNER, MARCO
Thesis abstract: Dynamic behavior of modern power system is increasingly influenced by the dynamics of power converters. At the generation level, a high volume of wind and solar energy with their large-scale power converters are replacing conventional synchronous generators. At the transmission level, many High Voltage Direct Current (HVDC) projects based on Modular Multilevel Converter (MMC) technology are commissioned to transfer offshore wind to the load centers, interconnect two non-synchronous AC grids, or two different nodes of the same AC grid (as an embedded link) to enhance the security of supply. The consumption level also faces such high integration of power converters since the modern flexible loads, such as electric vehicles, industrial motor drives, and recent hydrogen electrolyzers, are connected to the power system via power converters. Such transformation in generation, transmission, and consumption levels leads to the power dynamics that have never been experienced before in the conventional power systems.The high penetration of power converters may cause several challenges: reduction in the system total inertia and short-circuit current, excitation of undesirable interactions among control loops, reduction in stability margin, and loss of devices in the context of fault-ride through (FRT). Such challenges can be addressed by appropriate adjustments in the control systems of power converters.At the transmission level, this thesis focuses on improving the dynamic behavior of HVDC systems. A methodology is suggested to study the small-signal stability and evaluate potential interactions that may happen among control loops of two HVDC converter stations. Next, a multivariable controller based on H-inf design practice is developed to optimize the dynamic behavior of the system. As a follow-up study, mu-synthesis control approach is adopted to make HVDC control resilient against AC grid impedance variation. In the context of FRT performance, the fault operation of the HVDC system is improved by appropriate modification of the MMC control loops. Finally, a brief study on the DC voltage droop control design is conducted on a multi-terminal HVDC system. At the generation level, this thesis investigates the dynamic behavior of grid-forming control during fault events in a low-strength power system. It investigates the complication related to the existing grid codes and suggests two FRT controls for AC voltage support during fault recovery. As the last step, this thesis evaluates the feasibility of modern flexible loads to provide grid-forming services to the low-strength power grid. A hydrogen electrolyzer is used as an example and the operational constraints related to the hydrogen production are linked to the grid-forming functionalities.
- DAKIC, JOVANA: Tools for analysis of novel concepts of transmission systems for offshore wind power plantsAuthor: DAKIC, JOVANA
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 ELECTRICAL ENGINEERING
Department: Department of Electrical Engineering (DEE)
Mode: Normal
Deposit date: 04/11/2024
Reading date: 02/12/2024
Reading time: 09:00
Reading place: Aula Capella- ETSEIB- UPC - Avda. Diagonal, 647, Barcelona
Thesis director: GOMIS BELLMUNT, ORIOL | CHEAH MAÑÉ, MARC
Committee:
PRESIDENT: ERGUN, HAKAN
SECRETARI: BULLICH MASSAGUÉ, EDUARD
VOCAL: RUEDA TORRES, JOSE LUIS
Thesis abstract: Achieving the goals set forth by the Paris Agreement requires to cut global greenhouse gas emissions in half by 2030. Significant portions of high-emission technologies should be substituted with zero- or low-carbon alternatives in less than six years. Expanding renewable energy is crucial for transitioning to a sustainable energy landscape. Currently, the offshore wind industry stands at the brink of significant expansion, regarded as an efficient energy source due to high wind speeds at sea, great consistency, and lack of physical interference that are common on land or from human-made structures. In addition, the notable technological advances in wind turbine size and power ratings lead to an increase in volume of projects and investments.On the other side, the new connections of numerous inverters to the grid bring fast changing rules in the grid codes and challenge the development time line. Also, the high inflation rates affect the project costs and decelerate the energy transition.Early-phase planning of offshore wind projects is one of the primary steps that facilitates overcoming the challenges mentioned earlier. The benefit stands in developing a digital model of a potential wind power plant project to be able to anticipate future conditions and plan on a global scale. Therefore, this thesis focuses on determining cost effective solutions of transmission systems for integration of offshore wind power plants. A tool is developed to enable a thorough evaluation of key technical and financial characteristics of different type of transmission configurations and assessment of viability. Firstly, the focus is the optimal design of High Voltage Alternating Current (HVAC) systems, by including minimization of the cost with a special emphasis on benefits of installing a mid-cable reactor. The well-known rivalry between using HVAC and High Voltage Direct Current (HVDC) systems is analysed in detail for a range of offshore wind power plant rated powers and distances from the shore. Further on, the tool is expanded with the possibility to design the system to achieve grid code reactive power compliance. In addition, the offshore wind power plant is modelled more in detail, therefore maximum contribution of the wind turbines to the transmission system are studied. The collaboration with Vatenfall enabled application and validation of the tool based on data from existing and future projects.Finally, design of a novel transmission system including Low Frequency Alternating Current (LFAC) technology is investigated. The consequence of low frequency on the sizing and cost of the system is explained, while including a range of non-standard frequencies. Moreover, the comparison and break-even distance of all three technologies are presented.
DOCTORAL DEGREE IN ELECTRONIC ENGINEERING
- BANDAHALLI MALLAPPA, PRASAD KUMAR: Design and Implementation of High-Level Multilevel Inverters: Focusing on 15-level, 25-level, and 33-level Topologies with Asymmetrical Configuration and Optimal Component ChoicesAuthor: BANDAHALLI MALLAPPA, PRASAD KUMAR
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: Normal
Deposit date: 27/09/2024
Reading date: 21/11/2024
Reading time: 11:30
Reading place: Sala Polivalente A0.03. Planta 0. Edificio "A" de la EEBE del Campus Diagonal-Besòs.
Thesis director: MARTINEZ GARCIA, HERMINIO | VELASCO QUESADA, GUILLERMO
Committee:
PRESIDENT: BARGALLO PERPIÑA, RAMON
SECRETARI: VIDAL IDIARTE, ENRIQUE
VOCAL: FERNÁNDEZ HERRERO, CRISTINA
Thesis abstract: The primary goal of this thesis is to establish multilevel inverter (MLI) topologies for industrial settings. Because of its numerous benefits, including low power dissipation on powersupplies and low harmonic contents, MLI topologies are utilized in medium- and high-power applications, such as active power filters, FACTS devices, and machine currents. The chosenswitching strategies are crucial in removing harmonic distortion from the output voltage provided by the MLI. Depending on the inverter's power requirements, different topologies and controlstrategies may be selected. However, they have several drawbacks over MLI, such as the need for separate power sources for each stage. Consequently, MATLAB/SIMULINK is used to simulateMLI.This work aims to offer a unique topology for a single-phase 15-level asymmetric MLI to minimize component requirements. The suggested design uses asymmetric DC sources to reach amaximum 15-level output voltage through an H-bridge topology. To enable a 25-level version appropriate for renewable energy applications, the original 15-level MLI structure is furtherimproved, lowering system costs and dimensions. However, the higher component count in MLI presents reliability issues, particularly about the decrease of total harmonic distortion, whichcontinues to be a research focus. Several factors are examined for the proposed 15-level- and the extended 25-level MLI, including total standing voltage, multilayer inverter cost function, andpower loss. Next, it facilitates the integration of renewable energy sources and streamlines the use of components by contributing to a novel topology for 15-level asymmetric MLI. Even thoughmultilevel inverters have many benefits, future developments in this field must address reliability issues related to overall harmonic distortion reduction. Then, a unique 33-level asymmetricalsingle-phase MLI is built, utilizing fewer components and a lower Total Standing Voltage (TSV) at the switches. Variable-rated switches are employed to lower the overall cost of the inverter, andthe distribution of stress among the switches is carefully examined. The suggested design combines four asymmetrical DC sources with twelve switches to generate 33 voltage output levels.The inverter's performance is determined by many crucial factors, including TSV, efficiency, power loss, and cost function (CF). Using a range of combinational loads, the MLI was evaluatedin dynamic load conditions with unforeseen load disturbances, and it was discovered to be stable throughout the operation. A thorough comparison uses graphical representations based on stressvi across switches, stress distribution, switch count, DC source count, gate driver circuits, component count factor, TSV, CF, and other existing topologies. It is demonstrated to be more efficient andbetter in every way. According to simulation and experiments, the Total Harmonic Distortion (THD) is within IEEE guidelines. The suggested framework was created in MATLAB/Simulinkand tested using hardware in a lab environment.
- GON MEDAILLE, AXEL: Advanced characterization and modelling of innovative low-dimensional materials for solar cells applications Author: GON MEDAILLE, AXEL
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: Normal
Deposit date: 05/11/2024
Reading date: 20/12/2024
Reading time: 11:00
Reading place: Defensa pública en la Sala A2.14 del Edificio A del Campus Besós-EEBE
Thesis director: SAUCEDO SILVA, EDGARDO ADEMAR | JEHL, ZACHARIE VICTOR SAMUEL NATHANAEL
Committee:
PRESIDENT: PÉREZ RODRÍGUEZ, ALEJANDRO
SECRETARI: ORTEGA VILLASCLARAS, PABLO RAFAEL
VOCAL: DIMITRIEVSKA, MIRJANA
Thesis abstract: Energy transition keeps its course while new materials keep emerging promising better impact on environment. Among those materials, Q-1D chalco-halides materials using Bi and Sb, S, Se and I, Br, giving rise to wide combinations of materials. Most of them present the unique feature of a Pnma crystallographic structure allowing them to grow alongside one preferential direction, giving them optoelectronic properties highly seeked for PV applications, in particular for thin film solar cells. So far, Sb2Se3 has been the most investigated material within this class of material with an efficiency up until now of XX% in substrate configuration under AM1.5 spectrum illumination. Indeed, Sb2Se3 presenting the same crystallographic structure, is well-known within the PV community. However, despite having promising results over the past years, Sb2Se3-based solar cells reached a bottleneck in terms of efficiency. More generally, Q-1D chalco-halides materials either lack or do not have characterization data due to their recent emergence or re-emergence for some materials.This thesis will intend to address Sb2Se3 bottlenecks and present some solutions to allow Sb2Se3-based and other Q-1D chalco-halides solar cells to reach new heights through device modelling, present advanced characterization results from other Q-1D chalco-halides materials such as BiSeBr & SbSeI. Finally, the use of a novel material: Ti3C2Tx MXenes as selective contact suitable for those absorbers is also presented in this thesis. Firstly, a brief introduction of Sb2Se3 modelling parameters as well as BiSeBr & SbSeI results from by Raman spectroscopy and Time – Resolved Photoluminescence (TRPL) characterization are presented. A multi-wavelength investigation done by Raman spectroscopy coupled with novel Density Function Theory (DFT) are presented, giving information regarding the composition of the materials and the impact of the synthesis method for BiSeBr & SbSeI. Additionally, TRPL measurements highlighted the carriers’ dynamics and provide hints towards defects status of those materials. Altogether, this information helped to determine the potential of those new material as photo-absorber according to new figure of merit. Secondly, an emphasis is put on the device modelling using SCAPS-1D software and previous references to generate a qualitative model of Sb2Se3/CdS solar cells in substrate configuration to then design 2 numerical solutions to tackle the current bottlenecks experienced by the PV community. Those numerical solutions enable Sb2Se3 devices to reach 10.7% in efficiency by either implementing an ultrathin Al2O3 oxide intercalated between Sb2Se3 and CdS or operating a partial surface sulfurization on Sb2Se3 layer. Then, a simplified structure including only BiSeBr and 2 selective contacts was generated to pinpoint requirements from an electrical point of view. Although, due to software limitations, optical consideration is lacking to determine accurately suitable selective contacts, first approximations were determined through those simulations.Lastly, we develop the use of another novel material: MXenes Ti3C2Tx as a potential selective contact for Sb2Se3-based solar cells. Besides their wide range of deposition techniques and application, MXenes properties can be modulated alongside their synthesis. Initially, we perform materials characterization through Raman spectroscopy and X-Rays Diffraction (XRD) while changing intercalating agent and post deposition treatment (PDT) parameters to highlight this modulating feature. Then, we synthetized devices with Ti3C2Tx as hole transport layer (HTL) and Sb2Se3 as absorber. To improve carrier extraction, Se was incorporated on Ti3C2Tx layer under different PDT configurations. While PV performances were still poor compared to reference device without Ti3C2Tx some parameters presented some improvements upon Se incorporation onto Ti3C2Tx surface.
- JIMENEZ ARGUIJO, ALEX: Advanced strategies for the defect management in high efficiency kesterite solar cellsAuthor: JIMENEZ ARGUIJO, ALEX
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: 24/10/2024
Reading date: 13/01/2025
Reading time: 10:00
Reading place: Defensa pública a la Sala Polivalent del Campus EEBE (Besós)
Thesis director: SAUCEDO SILVA, EDGARDO ADEMAR | GIRALDO MUÑOZ, SERGIO
Committee:
PRESIDENT: GROSSBERG-KUUSK, MAARJA
SECRETARI: CAZORLA SILVA, CLAUDIO
VOCAL: CALVO BARRIO, LORENZO
Thesis abstract: Kesterite-based solar cells represent a promising avenue towards sustainable energy production due to their reliance on abundant, low-toxicity materials, aligning with global initiatives to minimize environmental impact and enhance energy security. This thesis contributes significantly to the field by advancing the understanding and efficiency of kesterite solar cells through innovative defect management strategies and the development of high-performance devices.The research initially focuses on developing a comprehensive and realistic model of kesterite solar cells, which is pivotal in bridging the theoretical predictions with experimental results, providing a robust framework for the analysis of the efficiency limitations and identifying avenues for enhancement. By incorporating a realistic depiction on the influence of defects on the device performance, this model sets a new benchmark for the assessment and optimization of thin-film solar cells. The innovative approaches for defect control within kesterite materials are central to the thesis. The research demonstrates that through precise defect control by an induced electric field or transient doping with small atoms, such as hydrogen and lithium, it is possible to significantly modulate the defect structure of kesterite absorbers. These modifications lead to the decoupling majority carrier density from minority carrier lifetime, effectively enhancing the performance and efficiency of the solar cells. These approaches not only improve the electrical properties of the material but also provides a method to systematically address the intrinsic limitations of kesterite semiconductors.Moreover, the thesis presents advancements in the synthesis and processing of kesterite solar cells, employing techniques such as solution processing, doping, and interface passivation. These methods have been shown to considerably improve the compositional uniformity and optoelectronic properties of the materials, driving the efficiencies closer to those required for commercial viability. Notably, the development of solution-processed kesterite solar cells emerge as a scalable and environmentally benign method, indicating a significant step towards the industrialization of this photovoltaic technology.The thesis concludes that the strategies and methodologies developed herein substantially enhance the understanding and performance of kesterite solar cells. The findings underscore the potential of these materials in the transition to renewable energy sources, highlighting their role in promoting a sustainable future. With further refinement and optimization, kesterite solar cells could play a critical role in the global energy landscape, offering a viable, cost-effective, and environmentally sustainable solution to meet the growing energy demands.In summary, the work presented in this thesis exemplifies a significant advance in the field of photovoltaics, offering practical solutions and novel insights that pave the way for further research and development towards achieving high-efficiency, sustainable solar energy techniques.
- JIMENEZ GUERRA, MAYKEL: Innovative bulk and interfaces management on Q-1D Sb2Se3 based solar cells Author: JIMENEZ GUERRA, MAYKEL
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: Normal
Deposit date: 31/10/2024
Reading date: 24/01/2025
Reading time: 10:00
Reading place: Defensa pública a l'Aula A1.08, EEBE, campus Besós
Thesis director: SAUCEDO SILVA, EDGARDO ADEMAR | SÁNCHEZ GONZÁLEZ, YUDANIA
Committee:
PRESIDENT: SPALATU, NICOLAE
SECRETARI: PLACIDI, MARCEL JOSE
VOCAL: GARCÍA SÁNCHEZ SÁNCHEZ, MARIO FIDEL
Thesis abstract: This thesis investigated antimony Q-1D (Sb)-based solar cells as a promising alternative for sustainable energy generation, addressing critical challenges related to material properties, interfaces, and device architecture. Innovative strategies were developed to optimize optoelectronic properties and improve conversion efficiency, focusing on Sb2Se3, but including also preliminary studies on the Sb2(S,Se)3 solid solution, as well as exploring cadmium-free (Cd-free) materials as electron selective transport layers (ETL).A major achievement was the optimization of the Sb2Se3/CdS interface using chemical etching techniques, such as KCN treatment, which increased the average efficiency of solar cells from 4% to 5%, reaching 5.3% in the best-performing sub-cell. These treatments not only enhanced surface passivation but also altered surface polarity, resulting in the formation of a "buried junction" that improved the fill factor and overall energy conversion efficiency.High-pressure thermal annealings proved effective in enhancing crystal quality by increasing grain size, promoting preferred crystal orientations, and reducing defect density, which enabled a 5.8% efficiency using a new co-evaporation method. These findings demonstrate the feasibility of these techniques to improve device performance and reproducibility.Cadmium-free or significantly Cd-reduced configurations were explored to reduce environmental impact, achieving an efficiency of 6.6% in superstrate-configuration devices based on Sb2(S,Se)3, approaching the 7.6% benchmark achieved with CdS. In the substrate configuration, a Cd-free Sb2Se3 cell reached an efficiency of 5.2%, surpassing the 4.8% achieved with CdS, highlighting the potential of alternative materials to replace cadmium.Despite the progress made, several challenges remain, such as ensuring the stability of Sb2Se3 interfaces under operational conditions and optimizing new materials like SbSeI and SbSeBr. Improving the scalability of fabrication processes and the cost-effectiveness of new treatments are also key areas for future research. The results of this thesis provide a solid foundation for developing more efficient and sustainable Sb2Se3-based solar cells, emphasizing the importance of continued innovation in materials science and device engineering to overcome the remaining challenges and advance toward more scalable and efficient photovoltaic technologies.
DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING
- ALTAMIRA ALGARRA, BEATRIZ: Bioplastic production by cyanobacteria-rich microbiomes. From field samples to productive culturesAuthor: ALTAMIRA ALGARRA, BEATRIZ
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: 05/11/2024
Reading date: 17/12/2024
Reading time: 10:30
Reading place: Campus Diagonal Besòs, Edifici A (EEBE). Sala polivalent, edifici A Av. Eduard Maristany, 16 08019 Barcelona
Thesis director: GARCIA SERRANO, JOAN | GONZALEZ FLO, EVA
Committee:
PRESIDENT: KRÖMER, JENS
SECRETARI: UGGETTI, ENRICA
VOCAL: BORIN, SARA
Thesis abstract: Biobased and biodegradable, like polyhydroxyalkanoates (PHAs), offer an alternative to petroleum-based plastics by reducing energy use and mitigating plastic waste. Among PHAs, polyhydroxybutyrate (PHB) is the most extensively studied, but its high production costs make it essential to explore novel production systems, like cyanobacteria. In addition, in the seek for exploring cost-effective strategies regarding PHB synthesis, the use of cyanobacteria rich microbiomes, or mixed cultures - a diverse microbial culture comprising various cyanobacterial strains and other microorganisms - is a strong option. However, research on cyanobacteria microbiomes for PHB production is relatively scarce.The present PhD thesis aims to contribute to this research gap by exploring the potential of cyanobacteria-enriched microbiomes, detailing the entire experimental process from field sample collection to the development of productive microbiomes in 3 liters (L) photobioreactors (PBRs). Additionally, it is also intended to provide fundamental insights to improve the production PHB process. To achieve the objective, seven samples were collected from different locations to obtain various microbiomes. A low concentration of phosphorus (0.2 mg·L⁻¹) was applied to promote the dominance of cyanobacteria. In an initial experiment to optimize PHB production, three factors were evaluated: organic carbon supplementation, inorganic carbon supplementation, and light cycles. The results showed that the addition of organic carbon, in the form of acetate, increased PHB production in all samples, reaching up to 14 % PHB in dry cell weight (dcw).In the attempt to develop a methodology to successfully obtain a productive photosynthetic microbiome, the operating mode in regards to nutrients, temperature, light, and carbon supplementation was evaluated in a 3 L PBR under non-sterile conditions. A two-stage approach was developed consisting in alternating seven days for biomass growth and seven days for PHB accumulation. During accumulation phase, acetate supplementation (600 mg·L⁻¹) combined with exposure to darkness resulted in different PHB yields across microbiomes. Of the seven microbiomes analysed, two stood out for their high PHB production, reaching peaks of 28 % and 37 %dcw, some of the highest levels reported in cyanobacteria. Three other microbiomes maintained sustained but lower production (12-15% dcw PHB), while the remaining two showed very low production (<5% dcw PHB) due to the presence of non-PHB-producing organisms, such as green algae. Analysis of 16S rRNA and gene expression revealed that the high PHB levels were associated with the overexpression of the phaC gene, responsible for PHB synthesis, and glgp1, involved in glycogen catabolism, indicating a relationship between the two metabolic pathways. Low PHB production was linked to the overexpression of the gltA gene, which diverts resources toward the Krebs cycle, away from PHB synthesis.Microscopy techniques successfully confirmed the presence of PHB granules within cyanobacteria cells. Further validation of the accumulated polymer as PHB was achieved through Raman spectroscopy, Fourier-transform infrared spectroscopy, and proton nuclear magnetic resonance.Finally, simultaneous production of up to 205 mg·L⁻¹ exopolyssacharides (EPS) and 12 %dcw PHB was achieved in a 3 L PBR. Notably, the presence of uronic acid in the EPS promoted biomass flocculation. Overall, this thesis tries to demonstrate the feasibility of using cyanobacteria rich microbiomes for long-term PHB production in a non-sterile system. The research provides valuable insights into the metabolic pathways involved and the microbial community contributing to the process, offering a multidisciplinary approach for optimizing cultivation factors and bringing this promising technology closer to pilot scale-up, paving the way for more sustainable and cost-effective bioplastic manufacturing technology.
- ARFELIS ESPINOSA, SERGI: Life cycle assessment as a tool for the industrialisation of chemical and mechanochemical processesAuthor: ARFELIS ESPINOSA, SERGI
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: 27/09/2024
Reading date: 21/11/2024
Reading time: 13:00
Reading place: Defensa pública lloc ETSECCPB UPC, Campus Nord Building C1. Classroom: 002 C/Jordi Girona, 1-3 08034 Barcelona
Thesis director: FULLANA PALMER, PERE | BALA GALA, ALBA | MALPARTIDA GARCIA, IRENE
Committee:
PRESIDENT: MAIRELES, PEDRO JESÚS
SECRETARI: DELGADO AGUILAR, MARC
VOCAL: CANALES MUÑOZ, ROBERTO IVAN
Thesis abstract: The chemical sector is a $4 trillion global business and a major employer, with chemicals present in almost all manufactured products. Increasing investment and the chemical industry's innovative capacity to provide safe and sustainable products will be vital in offering new solutions and supporting the ecological transition of our economy and society. Multiple approaches and tools have been developed to assist chemists in the development, design, and application of chemical products. The Life Cycle Assessment (LCA) approach, applied to the design of chemicals and processes, has helped scientists examine environmental impacts from a life cycle perspective. It provides a global view of environmental burdens, covering a broad set of environmental indicators such as Global Warming, Primary Energy Consumption, Water Use, Land Use, or Resource Depletion.This thesis is related to the application of LCA to the industrialization of chemical and mechanochemical processes. The first article presents a literature review of LCA for chemical processes. The second article is another review on mechanochemical processes. Chemistry and mechanochemistry are leading sectors in the application of LCA, but their methodology is still scarce. The development of these articles aims to provide a guide for the advancement of these topics. Additionally, the thesis continues with the evaluation of innovative technologies for chemical processes: production of calcium zincate as an ingredient for rechargeable batteries, cellulose extraction from wood chips, or nicotine extraction from tobacco leaves, for instance.It has been concluded that the choice of raw material is often the main source of environmental impact in a chemical process. Furthermore, mass and energy balances, as well as the type of energy supplied to power the process, are of great importance as part of the life cycle inventory. When selecting the functional unit (FU) for industrial chemical processes, where a given amount of product must be supplied within a given time frame, special attention must be paid. Although it falls outside the scope of cradle-to-gate LCA practice, variables such as reaction residence time can result in the final product having more service units or more functions. Therefore, this should be considered valuable additional information when deciding between alternatives. The LCA result with an FU that depends solely on mass does not account for this. Several chemical LCA studies already conduct assessments using flow rate as an FU. Another example is the consideration of module D within EN 15804:2012+A2:2019 for the inclusion of information outside the cradle-to-gate scope in LCAs of construction products.Moreover, the scalability of material flows from the laboratory scale, where data is obtained, to the pilot or industrial scale, where the process will be applied, is of crucial importance. For this purpose, different frameworks based on thermodynamic equations, as well as process modeling and simulation tools, have been used throughout the thesis. For instance, it has been observed that energy optimization from the lab to the industrial scale is around 20% on average, reaching maximum values of 90% for some equipment, such as the reactor used in Deasyl's laboratories. Finally, in LCA comparisons, an environmental impact evolution study is conducted, taking into account forecasts for electricity mixes in the coming years according to reports from the European Green Deal to interpret how the results will behave in the future.
DOCTORAL DEGREE IN MARINE SCIENCES
- SAMPER GARCIA, YAIZA JULIA: RENEWAL TIME AS A TOOL FOR WATER QUALITY CONTROL IN PORTS ENVIRONMENTS.Author: SAMPER GARCIA, YAIZA JULIA
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 MARINE SCIENCES
Department: Department of Civil and Environmental Engineering (DECA)
Mode: Article-based thesis
Deposit date: 12/07/2024
Reading date: 25/11/2024
Reading time: 11:00
Reading place: Defensa pública a l'Aula C2-212 de l'ETSECCPB
Thesis director: SANCHEZ-ARCILLA CONEJO, AGUSTIN | ESPINO INFANTES, MANUEL
Committee:
PRESIDENT: GARCÍA SOTILLO, MARCOS
SECRETARI: GRIFOLL COLLS, MANUEL
VOCAL: LORENTE JIMENEZ, PABLO
Thesis abstract: Currently, maritime transport plays a fundamental role in the global distribution of goods. In addition to their commercial function, ports are becoming of increasing importance in the recreational and tourism sectors. As a result, ports and the surrounding areas are subjected to strong environmental pressures, especially in the aquatic environment. This research analyses in six Spanish harbours the meteo-oceanographic variables that influence water inflows and outflows and, consequently, the renewal time of the harbours. This parameter can serve as an indicator of water quality in a semi-confined domain, as it is influenced by a wide range of factors, including environmental conditions, hydrodynamic characteristics and the harbour shape itself. The main objective of this doctoral thesis is to calculate and propose the use of the renewal time as a tool to control and improve water quality in port environments.The first part of this work is based only on observational data from measurement campaigns carried out in the ports of Barcelona, Tarragona and Castellón. This section analyses the meteorological and hydrodynamic conditions during the campaigns and investigates the occurrence of downwelling events under N/NE wind conditions, as well as upwelling events during S/W wind episodes. In addition, these events are related to variations in harbour renewal time and it is suggested that, under strong anticyclone conditions, the renewal time increases.The second study combines observations and numerical simulations to investigate the days with renewal times above the period mean in the ports of Huelva, Gijón and Cartagena. Using the results of the SAMOA system, it analyses the influence of atmospheric forcings such as wind and atmospheric pressure on the water exchanges between the port and the exterior. The results show that the majority of the days with a high renewal time can be attributed to wind events that favour the inflow of water into each port. Also, variations in atmospheric pressure lead to differences in water level between the inside and outside of the harbour, causing inflows or outflows of water that significantly affect the renewal time. In the third part of the thesis, the renewal time in the ports of Barcelona, Tarragona and Gijón is recalculated the LOCATE model, which integrates Eulerian hydrodynamic information from SAMOA and PARCELS, a Lagrangian particle solver. In this case, particle launches are simulated inside the harbours to study circulation and renewal trends both at the surface and at the bottom. The results show spatial variations both horizontally and vertically in all ports. Moreover, in the Mediterranean harbours (microtidal), the renewal time obtained at the bottom is higher than at the surface, however, in the Gijón harbour (mesotidal) the inverse is observed, it is higher at the surface.Throughout the three articles that compose it, the hydrodynamics of six Spanish ports have been characterized, combining the use of observational data with numerical simulations. This characterization allows for the study of water exchanges between the port and the exterior, as well as to calculate the renewal time, which is fundamental to guarantee the quality of the water in these semi-confined domains. The results have shown significant differences in the renewal time of the different harbours depending on the size and shape of the harbour, the environmental conditions and forcings, and the location and tidal regime. Therefore, it is essential to develop adapted management strategies based on the needs of each harbour to ensure adequate water quality.
DOCTORAL DEGREE IN MATERIALS SCIENCE AND ENGINEERING
- DE LA CRUZ JESUS, LUCIA GUADALUPE: Multifunctional eco-friendly aerogel composites for thermal insulation and fire resistant applications.Author: DE LA CRUZ JESUS, LUCIA GUADALUPE
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 MATERIALS SCIENCE AND ENGINEERING
Department: Department of Materials Science and Engineering (CEM)
Mode: Article-based thesis
Deposit date: 01/10/2024
Reading date: 22/11/2024
Reading time: 12:00
Reading place: Defensa pública EEBE, Sala Polivalente del Edificio A, planta baja, Campus Diagonal-Besòs
Thesis director: SANCHEZ SOTO, MIGUEL ANGEL | ABT, TOBIAS MARTIN
Committee:
PRESIDENT: MASPOCH RULDUA, MARIA LLUÏSA
SECRETARI: CASTILLO LÓPEZ, GERMAN
VOCAL: ECEIZA MENDIGUREN, MARÍA ARÁNZAZU
Thesis abstract: Replacing petroleum-based polymers with natural alternatives requires overcoming the limitations of their thermal and mechanical properties, as well as the inherently low fire resistance of the biomass from which they are derived. A common method for improving thermal insulation is through the use of porous systems such as technical foams. Aerogels, as highly porous materials, are lightweight and have low thermal conductivity, making them effective barriers for this purpose. However, the challenge remains in finding a solution where all the aforementioned properties are fully optimized. This thesis aims to demonstrate that by using environmentally friendly materials and processes, it is possible to create multifunctional aerogels with optimized properties, positioning them as viable alternatives, among others, to conventional foams.Polyvinyl alcohol (PVA), a biodegradable synthetic polymer, was initially studied with the introduction of alginate and tannic acid (TA) as natural modifiers and clay playing the role of structural scaffold. The hydrogen bonding between the polar groups of the components resulted in a nearly tenfold improvement in the mechanical properties as compared to pure PVA aerogels. The addition of NaOH was necessary to overcome the high hydrogen bonding attraction between TA and PVA that causes a fast precipitation of a solid which hindered gel formation. The PVA aerogel matrix was further cross-linked using calcium and borate ions, leading to an additional enhancement in mechanical performance, along with increased thermal stability and fire resistance, with the peak of heat release decreasing five-fold with respect to PVA.Gelatin—an abundant and cost-effective protein—was utilized as a novel system for developing optimized aerogel composites. Tannic acid played a crucial role in establishing strong bonds with the active sites of gelatin, a process that was carried out under alkaline conditions to stabilize the hydrogel complex. This approach resulted in exceptionally strong aerogels, achieving up to a 15-fold increase in yield stress. The protective action of well-dispersed nanoclay particles enhanced the pyrolytic decomposition and charring effects of tannic acid, imparting excellent flame-retardant properties to the aerogels. Although gelatins’ highly hydrophilic nature posed an initial challenge, a simple dip-coating treatment with polydimethylsiloxane and SiO2 nanoparticles effectively conferred superhydrophobic surfaces.Finally, the performance of modified ammonium alginate/clay/tannic acid composites was studied based on the orientation induced during the freeze-drying process. Alginate, a naturally abundant polysaccharide, was chosen as the base polymer for the aerogels due to its high fire resistance and the release of nitrogen upon heating, which reduces the amount of combustible gases. Orientation and crosslinking were key steps in enhancing the mechanical properties, achieving values as high as 305 MPa for Young’s modulus and 7 MPa cm³/g for yield strength, placing these systems among the highest reported in the literature. Thermal conductivity fit well with existing model predictions, increasing in axially oriented samples due to heat convection contribution through large vertical pores. Thermal stability and fire resistance were significantly improved by the addition of tannic acid, resulting in a minimal peak heat release of just 21 kW/m² and no detectable flame.New types of eco-friendly composite aerogels with an ultralight, porous structure have been developed. They were successfully fabricated using freeze-drying and post-cross-linking techniques, achieving an excellent balance of mechanical strength, thermal stability, and fire retardancy. In summary, this work demonstrates that bio-based and biodegradable aerogels can serve as a viable approach when seeking greener alternatives with properties comparable to current traditional foam-like materials.
- REZAYAT, MOHAMMAD: Effect of Laser Surface Texturing on Metastable Austenitic Stainless Steel AISI 301LNAuthor: REZAYAT, MOHAMMAD
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 MATERIALS SCIENCE AND ENGINEERING
Department: Department of Materials Science and Engineering (CEM)
Mode: Article-based thesis
Deposit date: 18/10/2024
Reading date: 13/12/2024
Reading time: 12:00
Reading place: EEBE, aula AA1.06, Campus Diagonal-Besòs
Thesis director: MATEO GARCIA, ANTONIO MANUEL | ROA ROVIRA, JOAN JOSEP
Committee:
PRESIDENT: CASALINO, GIUSEPPE
SECRETARI: FARGAS RIBAS, GEMMA
VOCAL: LAGUNA BERCERO, MIGUEL ÁNGEL
Thesis abstract: Laser Surface Texturing (LST) has emerged as a versatile and effective technique for modifying the surface properties of metallic materials, offering precise control over surface topography and microstructure. This PhD thesis presents a comprehensive investigation into the effects of LST on metastable austenitic stainless steel AISI 301LN, focusing on microstructural evolution, surface integrity, and corrosion resistance behavior.The study begins with a thorough characterization of the AISI 301LN, including an in-deep analysis of its chemical composition, microstructure, and mechanical properties, at different length scales. The material's inherent properties serve as a baseline for evaluating the effects of LST. Experimental analysis by doing a Design of Experiments (DoE) of the key-parameters for the LST process is conducted, trying to get a deep knowledge of the laser power, scanning speed, and focal distance position effects on austenitic stainless steels. A series of experiments are designed and executed to systematically vary these parameters, allowing for a detailed examination of their impact on surface morphology, grain structure, and phase composition.Microstructural evolution resulting from LST is investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). SEM micrographs reveal significant changes in surface topography, including the formation of grooves, ridges, and other microscale features induced by the laser beam. EDS analysis provides insights into changes in phase composition and/or transformation, such as the formation of α’-martensite near the surface due to rapid heating and cooling cycles induced during the laser processing. Mechanical properties of LST samples are evaluated at the micro- and macrometric length scale by using the Vickers hardness technique, leading to get a correlation between processing laser parameters and the material hardness. Surface hardness is found to increase with higher laser power and lower scanning speeds, attributed to changes in microstructure induced by thermal energy input.Statistical analysis is used to quantify the depth of the microstructural evolution zone, revealing the influence of laser power, scanning speed, and focal distance position on the depth profile. These findings provide valuable insights into the optimal processing conditions for achieving desired surface properties. Corrosion resistance of LST is assessed through immersion testing in molten carbonate salt environments, simulating harsh operating conditions encountered in industrial applications. Post-test analysis using SEM-EDS allows for the examination of oxide scale formation and corrosion mechanisms, with results indicating improved corrosion resistance for samples subjected to specific LST conditions.In general, this PhD thesis contributes to a deeper understanding of the complex interactions between the key LST parameters and the surface integrity from a different perspective of metastable austenitic stainless steel AISI 301LN. The comprehensive experimental approach, combined with advanced analytical techniques, enhances our knowledge of microstructural evolution, mechanical behavior, and corrosion resistance in metallic materials treated with the LST technique. These insights have significant implications for the development of advanced surface engineering techniques and the optimization of material performance in various engineering applications in the automotive, aeronautic, and medical, among other fields.
DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
- KARIMZADEGAN, KAVOOS: Fluidic Oscillator Numerical Modelling Considering Dimensional ModificationsAuthor: KARIMZADEGAN, KAVOOS
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 MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
Department: Department of Fluid Mechanics (MF)
Mode: Change of supervisor
Deposit date: 27/09/2024
Reading date: 12/12/2024
Reading time: 10:00
Reading place: Defensa pública presencial a l'aula 118-Edifici TR5-ETSEIAAT (Terrassa).
Thesis director: BERGADÀ GRANYÓ, JOSEP MARIA | MIRZAEI, MASOUD
Committee:
PRESIDENT: CASALS TERRE, JASMINA
SECRETARI: GONZÁLEZ CASTRO, JOSEP RAMON
VOCAL: HERRERO SABARTÉS, JUAN
Thesis abstract: Fluidic Oscillators (FO) may significantly improve flow mixing and cooling. However, they are mostly used in Active Flow Control (AFC) applications, where the pulsating flow they generate interacts with the boundary layer to typically postpone its separation. Before using any FO in an application, it is crucial to analyze the frequencies and amplitudes it may produce based on the incoming mass flow and its dimensions. The current work focuses on explaining this particular aspect in a somewhat innovative FO setup. We have preformed a numerical study of a conventional FO arrangement using both two-dimensional (2D) and three-dimensional (3D) approaches. Upon comparing the 3D and 2D data and analyzing the primary disparities, we made adjustments to the internal dimensions of the FO to assess the impact on its dynamic performance. The current findings clarify which are the internal dimensional alterations that provide greater output frequencies and amplitudes in the velocity field. An effort is made to examine the source of the self-sustained oscillations. According to the results of the numerical investigations, the dimensional modifications influenced the reverse flow inside the feedback channels, increasing/decreasing it at the feedback channels outlets, which had a clear effect on the frequency and on the operation of the device. When evaluating the forces acting on the jet as it enters the mixing chamber, the pressure momentum (pressure force) appears under all conditions studied, to be several times higher than the mass flow one, from which it can be concluded that this fluidic oscillator is pressure driven. As expected, the increase of the incoming flow Reynolds number, has a direct relation on the fuidic oscillator outlet frequency. The present research establishes for the first time a relation between the reverse mass flow in the feedback channels with the fluidic oscillator outlet frequency, the higher the feedback channel mass flow, the smaller the fluidic oscillator outlet frequency. Also has also been stated that, the 2D-CFD simulations, overestimated the feedback channel reverse flow.
- MORALES AVALOS, JORGE EDUARDO: Modeling of orthopedic surgeries using advanced biomechanical computational techniquesAuthor: MORALES AVALOS, JORGE EDUARDO
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 MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
Department: Department of Mechanical Engineering (EM)
Mode: Normal
Deposit date: 30/09/2024
Reading date: 13/12/2024
Reading time: 10:00
Reading place: Defensa pública a la sala Polivalent de l'EEBE.Campus Diagonal Besòs.
Thesis director: SERRANCOLÍ MASFERRER, GIL | SÁNCHEZ EGEA, ANTONIO JOSÉ
Committee:
PRESIDENT: GILL, RICHIE
SECRETARI: NOAILLY, JEROME BERNARD
VOCAL: PELFORT LOPEZ, XAVIER
Thesis abstract: This dissertation deals with the modeling and simulation of orthopaedic surgeries with the help of computational biomechanical techniques. These orthopaedic conditions are characterized by their geometry and mechanical interactions and need to be translated properly to a virtual environment. Besides engineering simulations such as stress and strain calculations, pre-surgery planning, development of patient-specific treatments and innovation on new surgical trends are some of the benefits that may result from the development of accurate and reliable orthopaedic in-silico models. To provide detailed digital models for the different fields of application, a strong collaboration with surgeons experts on the field has been considered. New knee orthopaedics surgical opportunities have appeared in the last decades oriented to minimizing the effect of diseases like \acrfull{koa}, such as proximal fibular osteotomy (PFO) and computational modeling might help to investigate their biomechanics in-silico. This work focus on the systematic development of in-silico PFO models that can be later on used to create proper and reliable virtual representations of patient-specific surgical treatment response.A major challenge for correctly representing anatomical models for virtual environments is developing a consistent data acquisition methodology and model reconstruction methods. By using \acrfull{fem}, generating accurate mechanical models of orthopaedic systems for a specific condition may provide a reliable baseline for all future virtual modeling approaches. Therefore, numerical simulations have been formulated based on real-world clinical case scenarios provided by our medical collaborators and partners. Mechanical models have be hence not only virtually investigated, but a comparison with respect to patient-specific treatments has been made. The biomechanical response of human joints, with particular interest on the knee, before and after surgical interventions has been herein investigated. These surgical interventions were pre-planned to provide the healthcare needed to the patients without this research work affecting any required medical care. The novel contribution of this investigation is the quantitative analysis of the impact of PFO on the biomechanics of the knee joint. The results provide mechanical evidence that PFO can effectively redistribute and homogenize joint stresses, while also repositioning the \acrfull{cop} towards the center of the knee, similar to what is observed post \acrfull{hto}. The findings propose PFO as a potentially viable and simpler alternative to conventional surgical methods for managing severe KOA, specifically in patients with medial compartment genu-varum.Furthermore, the computational techniques implemented will be optimized to produce the best possible results in the most efficient way. This research also marks the first application of FEMs that may support one of the underlying biomechanical theories of PFO, providing a foundation for future clinical and in-silico studies.
DOCTORAL DEGREE IN NATURAL RESOURCES AND THE ENVIRONMENT
- SIMONA PUJADÓ, JOSEP: A proposal for a new method to assess road traffic noise in the United KingdomAuthor: SIMONA PUJADÓ, JOSEP
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: Normal
Deposit date: 29/07/2024
Reading date: 21/11/2024
Reading time: 12:00
Reading place: Sala d'Actes EPSEM
Thesis director: VALLBE MUMBRU, MARC | ROSSELL GARRIGA, JOSEP MARIA
Committee:
PRESIDENT NO PRESENCIAL: TORIJA MARTÍNEZ, ANTONIO
SECRETARI: JORGE SANCHEZ, JUAN
VOCAL NO PRESENCIAL: AUSEJO PRIETO, MIGUEL
Thesis abstract: This thesis proposes a novel approach for assessing road traffic noise in the United Kingdom, aiming to partially revise the existing methodology outlined in the Design Manual for Roads and Bridges (DMRB). This assessment transcends the mandates of planning law and policy, encompassing obligations imposed by both common law and environmental legislation.The document re-examines the legal and regulatory stipulations that noise assessments must satisfy. It offers a thorough and lucid examination of the progression of noise legislation in England, tracing the history of rail, road, and aircraft noise from their inception to the present.Upon establishing the legal and regulatory prerequisites, the thesis conducts a critical analysis of the prevailing planning policies concerning noise, considering factors such as sustainability and good design principles. Subsequently, it scrutinises the methodology currently prescribed in the DMRB.The thesis then delves into cost-benefit analysis, exploring its application in evaluating road traffic noise and the implementation of noise abatement strategies. With this groundwork in place, it introduces a proposition to modify the existing DMRB methodology.The proposed amendments encompass four key aspects:1. Expanding the reporting of impacts to include both individual receptors and the wider community, thereby addressing the stipulations of common and environmental law.2. Shifting the focus from reporting ‘impacts’ to reporting ‘effects’.3. Elucidating the cost-benefit analysis involved in the adoption of noise reduction measures.4. Assigning a monetary value to noise effects, which could serve as an indicator of a project’s significance.This refined approach aims to enhance the framework for noise assessment, ensuring a more holistic and effective evaluation of road traffic noise implications.Furthermore, the research presented in this thesis investigates the factors that must be considered in any proposal that contemplates replacing the current road traffic noise prediction methodology (CRTN) with a new method based on the Harmonoise European research project. It specifically focuses on the decision-making process regarding the introduction of a noise mitigation measure (where a noise fence is taken as an example of one of such mitigation measures). This decision-making process should include not only the cost of the mitigation measure but also the cost of any compensation to be paid for the loss of value in an interest of land under the Land Compensation Act 1973.
DOCTORAL DEGREE IN NUCLEAR AND IONISING RADIATION ENGINEERING
- CURCOLL MASANES, ROGER: Enhancing greenhouse gases flux estimates through improved atmospheric radon monitoring using the Radon Tracer MethodAuthor: CURCOLL MASANES, ROGER
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 NUCLEAR AND IONISING RADIATION ENGINEERING
Department: Institute of Energy Technologies (INTE)
Mode: Normal
Deposit date: 27/09/2024
Reading date: 05/12/2024
Reading time: 12:00
Reading place: Defensa pública a la Secció d'Enginyeria Nuclear, pavelló C', planta 1, porta 31.07, ETSEIB.
Thesis director: VARGAS DRECHSLER, ARTURO | GROSSI, CLAUDIA
Committee:
PRESIDENT: FONT GUITERAS, LLUÍS
SECRETARI: PINO GONZALEZ, DAVID
VOCAL: HERNANDEZ CEBALLOS, MIGUEL ANGEL
Thesis abstract: Anthropogenic greenhouse gas (GHG) emissions are the main drivers of global warming and climate change. Despite advancements in sources quantification, uncertainties persist in the quantification of carbon dioxide (CO2) and methane (CH4) emissions, both biogenic and anthropogenic. The Paris Agreement has heightened the need to reduce these uncertainties through independent observations and methodologies.This work has focused on improving the estimation of GHG fluxes through the application of the Radon Tracer Method (RTM). This methodology combines high-quality measurements of atmospheric radon and of the GHGs of interest with radon flux data from the footprint of the stations to quantify GHG fluxes. Radon fluxes are obtained by combining radon flux maps with atmospheric transport models.In the first part of the thesis, a high-sensitivity monitor (ARMON v2) for measuring atmospheric radon was developed, calibrated, and compared with other monitors. The ARMON v2 is an improved version of a previous monitor designed by the Institute of Energy Techniques (INTE). Its detection principle is based on the deposition of 218Po+ particles on a semiconductor detector by applying a voltage of 10kV in the detection volume. The ARMON v2 was designed to meet the necessary requirements for measuring radon at atmospheric stations and to serve as a reference monitor for the in-situ calibration of other devices. It is more robust, portable, and easier to use than its predecessor and includes software that allows full control and real-time data visualisation.The detection efficiency of the new ARMON v2 was obtained both theoretically and experimentally. Theoretically, the collection of 218Po+ particles on the detector surface was simulated. Experimentally, it was calibrated in radon chambers at the INTE and PTB (Germany), obtaining efficiency values of 0.0057 s-1 Bq m-3 and 0.0059 s-1 Bq m-3 respectively. Uncertainty analysis gave values below 10% for radon concentrations above 5 Bq m-3. Additionally, the response of the ARMON v2 was compared with other devices at atmospheric stations in France and Germany. The ARMON v2 will be commercialised by Radonova, a company to which the usage licence has been granted.In the second part, the atmospheric transport model Flexpart-WRF and the radon flux maps developed under the traceRadon project, both used in the subsequent application of the RTM, were validated. Validation was carried out by modelling radon concentration, combining Flexpart-WRF simulations with radon flux maps at three stations: SAC (near Paris, France), DEC (Ebro Delta, Spain), and BII (Barcelona, Spain). The latter two present complex terrain due to their proximity to the sea and sea breeze regimes.In the final part, RTM was applied at DEC and BII. At DEC, CH4 fluxes associated with rice cultivation were quantified, while at BII, metropolitan emissions of CO2 and CH4 were measured. The results at DEC show a high correlation with previous studies conducted using accumulation chambers. Moreover, they reveal that inventories such as EDGAR do not adequately account for agricultural emissions from the Ebro Delta. At BII, the RTM results were compared with EDGAR for CH4 and with four inventories for CO2. The RTM-estimated fluxes align with inventories in terms of low seasonality and magnitude, but variability among inventory values makes their evaluation challenging.The application of RTM, together with atmospheric transport models such as Flexpart-WRF, offers an alternative and independent methodology for quantifying and observing the seasonal variability of GHG fluxes in complex areas with anthropogenic emissions. Furthermore, the need to improve the precision of radon flux maps to increase the reliability of estimates is emphasised.
DOCTORAL DEGREE IN OPTICAL ENGINEERING
- GAL, EYAL: Clinical comparison of two specialty soft lenses for KeratoconusAuthor: GAL, EYAL
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 OPTICAL ENGINEERING
Department: Department of Optics and Optometry (OO)
Mode: Normal
Deposit date: 30/09/2024
Reading date: 28/11/2024
Reading time: 10:30
Reading place: Auditori Joan Salvadó del Centre Universitari de la Visió - https://meet.google.com/vqk-vvvz-poh
Thesis director: GANTZ, LIAT
Committee:
PRESIDENT: SHNEOR, EINAT
SECRETARI: LAMARCA MATEU, JOSE
VOCAL: TRAVE HUARTE, SONIA
Thesis abstract: Due to advanced diagnostic instruments for detection of early-stage keratoconus (KC), and procedures that halt its progression such as corneal collagen cross-linking (CXL), optometry clinics are now seeing less severe cases of irregular corneas. As a result, optometrists are treating earlier stages of KC, and contact lens (CL) solutions for earlier stages of the disease are warranted. This thesis comprehensively evaluated the utility of two specialty soft lenses for KC of varying diameters and thicknesses in 40 eyes (N=20, mean age: 39±10, range: 23-55 yrs.) with KC grade 1 or 2 (based on Amsler-Krumeich) using a randomized, crossover, prospective longitudinal (up to one year follow-up) clinical design. The visual quality, contrast sensitivity, higher order aberrations (HOA), subjective satisfaction and wearer preference were compared between SoftK2 and Semi-scleral SoftK lenses. Objective visual outcomes were also compared with those obtained with gold-standard RGP lenses. Both soft lens designs significantly improved high contrast visual acuity (SoftK2 0.05±0.07, Semi-scleral SoftK 0.10±0.09LogMAR) compared with the habitual state (0.23±0.27 LogMAR). SoftK2 lenses provided low contrast VA 0.29±0.15 LogMAR), high contrast VA (0.04±0.06 LogMAR), contrast sensitivity (1.55±0.12 Log units), and HOA similar to GP lenses (low contrast visual acuity 0.27±0.17 Log MAR, high contrast visual acuity 0.07±0.07 LogMAR and contrast sensitivity 1.55±0.10 LogCS units). With low contrast, Semi- scleral SoftK did not show statistical significance compered to SoftK2 and from habitual state (0.40±0.2 Semi-scleral SoftK 0.52±0.3 habitual). No adverse events, limbal or conjunctival redness, papillary reaction, unusual appearances, or patient complaints requiring clinical action were noted at any of the follow-up visits with either lens type. The SoftK2 lens was preferred by 75% of the participants and had fewer participants with reported adverse events of dryness sensation after two weeks of wear. More participants continued its use over a period of 12-month with SoftK2 (7 participants were still using SoftK2 after 12 months, while no one was with Semi- scleral SoftK).SoftK2, Semi-scleral SoftK, and scleral GP lenses showed significant improvements of coma, trefoil, and tetrafoil HOAs compared to the uncorrected state, without significant differences between the lenses. SoftK2 and Semi-scleral SoftK lenses induced corneal swelling with clinically significant values in the periphery (7%-9% higher than the habitual state), which implies careful monitoring of eventual physiological adaptation changes to sustained hypoxia induced by the lens over time.The soft lenses were expected to only partially correct the refractive error of the KC participants leaving a small residual astigmatism. Since no clinical test currently exists to detect alterations in visual perception due to residual uncorrected astigmatism, an early part of the dissertation, was devoted to examining the utility of a novel test developed by Prof. Arnold Wilkins (UK), theWilkins Egg and Ball Test (WEBT) to address this question. The results of the WEBT were compared between three cohorts: 32 normal participants (mean age: 24±5) under baseline and induced cylinder ,22 keratoconic eyes (N=13, mean age: 36±12) and 23 astigmatic participants (mean age: 36±12). The WEBT was found to be sensitive to overall blur and not to residual astigmatic blur. Its measurements with Soft K2 compared with Semi-scleral SoftK lenses were not significantly different.We conclude that specialty soft lens designs for keratoconus are a viable alternative for KC patients with Stage 1 or 2 in terms of visual quality and tolerance. However, more research is needed to evaluate the long term eventual physiological implications of induced corneal swelling.
DOCTORAL DEGREE IN PHOTONICS
- BERNAL TEXCA, FRANCISCO GUMARO: Photonic based approaches to overcome intrinsic losses in organic solar cellsAuthor: BERNAL TEXCA, FRANCISCO GUMARO
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 PHOTONICS
Department: Institute of Photonic Sciences (ICFO)
Mode: Normal
Deposit date: 18/10/2024
Reading date: 29/11/2024
Reading time: 11:00
Reading place: ICFO, Mediterranean Technology Park, Avinguda Carl Friedrich Gauss, 3, 08860 Castelldefels, Barcelona
Thesis director: MARTORELL PENA, JORDI
Committee:
PRESIDENT: PUIGDOLLERS GONZALEZ, JOAQUIN
SECRETARI: LIGUORI, NICOLETTA
VOCAL: ARMIN, ARDALAN
Thesis abstract: The large dependence on fossil fuels led to a severe environmental crisis, evident in the acceleration of climate change caused by the greenhouse effect. This unsustainable model has led to a reassessment of our energy infrastructure, which has initiated a shift towards more sustainable energy sources. Renewable energy sources, such as wind, hydro, and particularly solar, provide a more sustainable alternative. Solar energy, which can be transformed into electrical energy by photovoltaic (PV) cells, is notable for its abundant availability and minimal environmental impact. However, intrinsic fundamental losses in solar energy conversion limit the power conversion efficiency (PCE) of single-junction planar geometry solar cell devices to 33.1%, as described by the Shockley-Queisser detailed balance model. In this thesis, we address the study of two fundamental losses limiting the maximum efficiency achievable by planar-geometry single-junction solar cells. We consider the approach on organic solar cell (OSC)s because they offer significant benefits over traditional inorganic-based cells. OSCs, made from carbon-based materials, can be flexible, integrable, lightweight, and potentially less costly to produce. These qualities make OSCs a promising innovation for incorporating solar power into a wider range of applications, advancing the pursuit of a cleaner, more sustainable energy future. The thesis is organized into four main chapters. In Chapter 1 we discuss global energy demand and positioning solar energy as a sustainable alternative. It also covers a discussion on the intrinsic losses leading to the fundamental limits in solar energy conversion. Chapter 1 also provides an overview of the state-of-the-art OSCs, including the properties of organic semiconductor materials and device photophysics, and concludes with a justification for the research developed and described in the rest of the thesis. Chapter 2 focuses on mitigating transmission and thermalization losses by employing a tandem strategy. To overcome some of the limitations of the two-terminal configuration, we develop a four-terminal tandem structure composed of a transparent front and an opaque back cell, thus enhancing fabrication feasibility and overall performance. Chapters 3 and 4 delve into Boltzmann losses linked to a mismatch between the absorption and emission cones that directly impact the maximum achievable open-circuit voltage (Voc). In Chapter 3, we investigate the mechanisms governing the quasi-Fermi level splitting (QFLS) dynamics in OSCs. Our study identifies direct radiative recombination and recombination via trapping states as the two primary competing processes controlling the QFLS in PM6:Y6 solar cells. We propose a strategy to passivate trap states, leading to a reduction in mid-gap trap states density and, consequently, an increase in Voc. We highlight the role played by radiative recombination in regulating the final Voc of such PM6:Y6 solar cell. Chapter 4 builds on these findings by leveraging the emitted photons to experimentally demonstrate an Voc enhancement through the restriction of photon emission, thereby reducing Boltzmann losses. We demonstrate that using a two-optical resonance cavity configuration, we can obtain a reduction in the mismatch between the absorption and emission cones in OSCs. We experimentally demonstrate a solely optical-based Voc increase larger than 30 mV. In summary, the findings in the present thesis establish an optical-based path to increase Voc and the performance of the solar cells and eventually surpass the Shockley-Queisser PCE limit for planar-geometry single-junction solar cells.
- BUOB, SANDRA: Quantum-gas microscopy of strontium Bose- and Fermi-Hubbard systemsAuthor: BUOB, SANDRA
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 PHOTONICS
Department: Institute of Photonic Sciences (ICFO)
Mode: Normal
Deposit date: 16/10/2024
Reading date: 22/11/2024
Reading time: 10:00
Reading place: ICFO, Mediterranean Technology Park, Avinguda Carl Friedrich Gauss, 3, 08860 Castelldefels, Barcelona
Thesis director: TARRUELL PELLEGRIN, LETICIA
Committee:
PRESIDENT: HOLGER ESSLINGER, TILMAN
SECRETARI: LOZA ALVAREZ, PABLO
VOCAL: GROSS, CHRISTIAN
Thesis abstract: Ultracold atoms have proven to be a valuable asset to study and understand complex quantum many-body systems in a well-controlled setting. In particular, quantum-gas microscopes provide unprecedented access to local observables and allow one to investigate those systems at the level of each individual particle, giving new insights on their behaviour. While so far most of these microscopes used alkali atoms, the distinct properties of alkaline-earth atoms, in particular strontium, combined with quantum-gas microscopy are expected to shed new light on a broad variety of many-body problems. This thesis describes the realization of single-site-resolved imaging for both bosonic and fermionic strontium atoms in a Hubbard-regime optical lattice, which unlocks the possibility to study novel types of Bose- and SU(N) Fermi-Hubbard systems.An essential step in ultracold-atom experiments is the preparation of a quantum degenerate cloud. In the first part of this thesis, we discuss the methods we have implemented in our apparatus to achieve this goal. We developed a new resonant-shielding method to double the atom number during the first cooling stage in a broad-linewidth blue magneto-optical trap. During the second cooling stage in a narrow-linewidth red magneto-optical trap, the hyperfine structure of the fermionic atoms adds additional challenges which are addressed by mixing the hyperfine states with an additional laser for efficient trapping and cooling. After the laser-cooling stages, we perform evaporative cooling in a far red-detuned optical potential before loading the atoms into a two-dimensional optical lattice. The lattice laser operates at the clock-magic wavelength of strontium (813.4nm) which will enable high-precision measurements in future experiments.To image the individual atoms in the optical lattice, we place a high-NA objective in close vicinity to the atoms. We demonstrate single-atom resolution for bosonic and fermionic strontium and successfully reconstruct the lattice occupation for both of them, reaching fidelities as high as 96%. For the bosonic Sr-84 atoms, we induce fluorescence on the blue broad-linewidth transition and simultaneously perform attractive Sisyphus cooling on the red narrow-linewidth transition. Moreover, combining this imaging method with momentum-space detection, we observe the matter-wave interference arising from the phase coherence of the Bose-Hubbard superfluid. For the fermionic Sr-87 atoms, we image with the red transition only, which allows us to obtain for the first time for a fermionic alkaline-earth atom both single-atom resolution and spin-resolved detection.This thesis has combined, for the first time, quantum-gas microscopy with ultracold strontium and its distinct spectral properties. This platform should enable a broad range of future studies. For the bosons, it unlocks investigation of the single-atom-resolved dissipative Bose-Hubbard systems and the exploration of collective atom-photon scattering in ordered atomic arrays. For the fermions, the spin-dependent single-atom detection provides the ideal setting for investigations of antiferromagnetic correlations in SU(N≤10) Fermi-Hubbard systems and the realization of exotic magnetic phases.
- FRAUENDORF BRANCO CENNI, MARINA: Correlations and Measurements as Resources for Quantum Information TasksAuthor: FRAUENDORF BRANCO CENNI, MARINA
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 PHOTONICS
Department: Institute of Photonic Sciences (ICFO)
Mode: Normal
Deposit date: 16/10/2024
Reading date: 25/11/2024
Reading time: 10:00
Reading place: ICFO, Mediterranean Technology Park, Avinguda Carl Friedrich Gauss, 3, 08860 Castelldefels, Barcelona
Thesis director: ACÍN DAL MASCHIO, ANTONIO
Committee:
PRESIDENT: SANPERA TRIGUEROS, ANNA
SECRETARI: LEWENSTEIN, MACIEJ
VOCAL: PERARNAU LLOBET, MARTI
Thesis abstract: The advent of quantum mechanics, which predicted strange, counter-intuitive effects and phenomena, that could not be mimicked by classical physical theories, revolutionized the scope and understanding of physics research back in the XIX century. As time passed, and quantum theory became better understood, a shift of paradigm occurred: what used to be solely an object of investigation and analysis became also a tool, as it was realized that the extraordinary, exotic features of systems working in the quantum regime could also be harnessed as resources that could be used to our benefit in different tasks. This shift of paradigm marked the beginning of a Second Quantum Revolution, which was characterized by the rise of the Quantum Information Science and Technologies. Central quantum resources such as quantum correlations, including entanglement, and also non-classicality and non-Gaussianity, were shown to be useful for data processing tasks such as communication, computation and parameter estimation, to name a few. In this thesis, we dive into the field of parameter estimation, or Metrology, and discuss the role of physical correations on the precision of the information retrieval of variables encoded in physical systems. We begin by exploring the role of a specific kind of correlations, those that arise indirectly between quantum probes via the interaction with a common environment, in the retrieval of temperature information of a cold bosonic bath. We then analyse the role of restricting the measurement choice of the probes to a limited set, that of Gaussian measurements, and show their usefulness in characterizing the temperature of Gaussian systems. Finally, we go beyond the scope of the field of Metrology and Thermometry, and look for effective ways to certify the presence of a number of relevant quantum resources in states produced by third order light-matter interaction, also known as three photon generation. There, we show that correctly tailored quantum witnesses can effectively certify the presence of quantum phenomena with no classical analog in photonic nonlinear processes.
- MACARONE PALMIERI, ADRIANO: Deep learning for boosted quantum state estimation and bath parameter extractionAuthor: MACARONE PALMIERI, ADRIANO
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 PHOTONICS
Department: Institute of Photonic Sciences (ICFO)
Mode: Normal
Deposit date: 22/10/2024
Reading date: 11/12/2024
Reading time: 10:00
Reading place: ICFO, Mediterranean Technology Park, Avinguda Carl Friedrich Gauss, 3, 08860 Castelldefels, Barcelona
Thesis director: LEWENSTEIN, MACIEJ
Committee:
PRESIDENT: HA KYAV, THI
SECRETARI: LIGUORI, NICOLETTA
VOCAL: GARZANITI, NICOLA
Thesis abstract: The thesis explores the application of supervised deep learning (DL) to mitigate noise in quantum state estimation protocols, to offer a viable tool for quantum technologies development, that leverages quantum properties, like entanglement. This is vital for quantum information processing and is used in applications like quantum teleportation, quantum key distribution, and superdense coding. However, the practical implementation of these technologies is challenged by noise and errors, making accurate certification of quantum states essential.Traditionally, state tomography is the best possible desiderata, but it is resource-intensive. Alternative methods with better scaling, such as permutationally invariant states and shadows, have been proposed, though they are limited in scope, because limited to specific classes of states or can estimate some quantum properties only. The thesis specifically investigates whether supervised DL can be used to mitigate noise and achieve full quantum state estimation under various conditions, including limited resources, different noisy sources, and, last, incomplete information.The research introduces a novel approach using the out-of-distribution paradigm to extend the applicability of supervised deep learning to unknown data distributions, such as noisy quantum states measured with imperfect setups. This study at a higher depth the generalization ability of deep learning protocols while maintaining the simplicity of trained supervised neural networks. In this way, seamless application from synthetic to experimental data is allowed. At the same time, the computational aspect involves analyzing the complexity of different models and their learning abilities, and noise mitigation capabilities, and showcasing transformer-based models in certifying genuine k-body entanglement as superior.Lastly, the thesis addresses noise characterization using deep learning, particularly how this can infer environmental noise parameters from a single-qubit probe without fixed-time conditions. This contributes to better noise reduction and system control in quantum technologies.
- ORSINI, LORENZO: A Topological Nanophotonics platform based on hyperbolic phonon-polaritonsAuthor: ORSINI, LORENZO
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 PHOTONICS
Department: Institute of Photonic Sciences (ICFO)
Mode: Normal
Deposit date: 10/10/2024
Reading date: 19/12/2024
Reading time: 12:00
Reading place: ICFO, Mediterranean Technology Park, Avinguda Carl Friedrich Gauss, 3, 08860 Castelldefels, Barcelona
Thesis director: KOPPENS, FRANK
Committee:
PRESIDENT: ALONSO GONZÁLEZ, PABLO
SECRETARI: GARCÍA DE ABAJO, JAVIER
VOCAL: GIANNINI, VICENZO
Thesis abstract: Topological Nanophotonics is an emerging interdisciplinary field that offers a groundbreaking approach to control and manipulate light at the nanoscale. It combines principles from Topology, Photonics, and Nanotechnology to investigate the captivating behavior of light when confined to structures on the nanometer scale. A main goal of the community is to achieve topological edge states deeply confined below the diffraction limit. Despite promising theoretical and experimental progress, achieving these edge states in a Nanophotonic system remained elusive until now.This thesis is devoted to achieving these Topological edge states in a Nanophotonic system by combining several methods. First, we used natural hyperbolic materials to take advantage of their high-quality sub-diffraction-limit electromagnetic modes, known as hyperbolic phonon polaritons. Additionally, we employed an indirect patterning technique to fabricate nanophotonic devices, solving fabrication-induced issues and allowing for the precise control over the nanostructures. Finally, we characterized these Nanophotonic systems using scattering-type scanning near-field optical microscopy. Achieving deep subwavelength topological edge states required several foundational achievements:Quantitative Polaritonic Near-Field Analysis:Scattering-type scanning near-field optical microscopy is a powerful imaging technique for studying materials beyond the diffraction limit. However, interpreting near-field measurements poses challenges in mapping the response of polaritonic structures to meaningful physical properties. To address this, we developed a theory using the transfer matrix method to simulate the near-field response of 1D polaritonic structures. This efficient and accurate analytical theory maps the near-field response to well-defined physical properties, enhancing the understanding of near-field images and complex polaritonic phenomena. Advancing the Hyperbolic Platform:The physics underlying our hyperbolic platform was largely unexplored, leading to a significant gap in understanding the fundamental properties and control methods of indirect patterned hyperbolic materials. Our studies provided new insights into the behavior of hyperbolic phonon polaritons in indirect patterned systems. We achieved three key results: first, we gained new insights into the fundamental behavior of hyperbolic phonon polaritons providing a deeper understanding of their interactions within indirect patterned systems; second, we investigated indirect patterned hyperbolic nanocavities achieving record-breaking quality factors, approximately 80, while maintaining the mode volume five orders of magnitude smaller than the free-space excitation wavelength; and third, discovering that the coupling mechanism between cavities is radiative, significantly impacting the design of lattices and photonic crystals using indirect patterning. Achieving Deep Subwavelength Topological Edge States:We experimentally demonstrated deep subwavelength topological edge states by implementing a one-dimensional lattice based on the Su-Schrieffer-Heeger model. The topological edge state was confined in a sub-diffraction volume of 0.021μm³, four orders of magnitude smaller than the free-space excitation wavelength volume used to probe the system, while maintaining a resonance quality factor above 100.
- VINCENT, STEPHY: Solution Processed Colloidal Quantum Dot-Based Short Wave Infrared Light EmittersAuthor: VINCENT, STEPHY
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 PHOTONICS
Department: Institute of Photonic Sciences (ICFO)
Mode: Normal
Deposit date: 25/10/2024
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: KONSTANTATOS, GERASIMOS
Committee:
PRESIDENT: ANTHOPOULOS, THOMAS
SECRETARI: BURGUES CEBALLOS, IGNASI
VOCAL: CHRISTODOULOU, SOTIRIOS
Thesis abstract: Shortwave infrared (SWIR) light sources are highly significant due to their ability to interact with molecular bonds and penetrate materials with reduced scattering and absorption. These properties make SWIR light exceptionally valuable across diverse applications, including spectroscopic analysis, non-invasive biomedical imaging, food and agriculture, and environmental monitoring. However, traditional SWIR sources tend to be bulky, inefficient, and characterized by high bulb temperatures, prolonged warm-up times, limited dimming capabilities, relatively short lifespans, and high costs. This has resulted in an increasing demand for more efficient, compact, and cost-effective alternatives.Solution-processed colloidal quantum dots (CQDs) are promising candidates for advanced SWIR light sources due to their wavelength tunability, high photoluminescence quantum yield (PLQY), and cost-effective synthesis. While CQD-based light sources are well-established in the visible range, there is a need for further development of SWIR emitters. This thesis addresses this gap by utilizing CQDs to create efficient, flexible SWIR light emitters through a simplified and cost-effective fabrication method.We developed SWIR light emitters with an emission wavelength of around 1350 nm using the down-conversion (DC) technique, where lead sulfide (PbS) quantum dots (QDs) absorb high-energy photons and emit lower-energy SWIR photons. Down-conversion using QDs addresses certain drawbacks of conventional phosphor-converted LEDs based on lanthanides or transition metal ions, such as the need for complex fabrication processes involving high-temperature sintering or annealing, limited emission band tunability, and challenges in supporting pulsed operations. We used binary blends of large-bandgap matrix QDs and small-bandgap emitter QDs, as they are reported to improve the PLQY.Initially, flexible DC films were fabricated on PET substrates via solid-state ligand exchange (SSLE) and spin coating, with various ligands, including 3-Mercaptopropionic Acid (MPA), combinations of Zinc Iodide (ZnI2) and MPA, and combinations of 1-Ethyl-3-methylimidazolium Iodide (EMII) and MPA, studied. The best performance was achieved using MPA as the ligand, and selectively exciting the emitter QDs proved more efficient than exciting both matrix and emitter QDs. The DC film treated with MPA, when excited by a 980 nm LED produced a SWIR power density of 0.19 mW mm⁻². Despite these promising results, spin coating was found to be inefficient and labor-intensive, necessitating a more scalable method.To address this, we developed an alternative fabrication method using ethyl cellulose (EC) polymer, where oleic acid-capped QDs are mixed with EC to form flexible QD-EC composites. This approach is industrially adaptable, reduces QD usage by a factor of 20, eliminates wastage, and requires less manual effort than the SSLE process. It also allows for scalable fabrication of DC films in any size or shape. The maximum SWIR power density achieved for a DC film with OA-capped PbS QDs, without ligand modification, was 0.18 mW mm⁻² .To further enhance efficiency, we applied solution-phase ligand exchange (SPLE) using 1-dodecanethiol (DDthiol) to improve surface passivation and reduce non-radiative recombination. DC films made with DDthiol-treated PbS QDs demonstrated a three-fold increase in SWIR power output and reduced efficiency roll-off by 37% at higher excitation power, compared to films with oleic acid (OA)-capped QDs. The best-performing film, composed of DDthiol-treated matrix QDs and OA-capped emitter QDs, achieved a maximum SWIR power density of 0.54 mW mm⁻² . This methodology was further extended to develop SWIR light sources emitting at 1470 nm. In summary, we developed efficient and flexible SWIR light sources using solution-processed CQDs through a cost-effective and scalable fabrication method by overcoming the limitations of conventional sources.
DOCTORAL DEGREE IN POLYMERS AND BIOPOLYMERS
- BALLESTAR DE LAS HERAS, RICARDO LUIS: Manufacturing and recycling of polyolefins and biopolymers in a circular economy model. Mechanical, thermal and morphological characterization of polymers and high-performance films.Author: BALLESTAR DE LAS HERAS, RICARDO LUIS
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 POLYMERS AND BIOPOLYMERS
Department: Department of Chemical Engineering (EQ)
Mode: Article-based thesis
Deposit date: 26/07/2024
Reading date: 22/11/2024
Reading time: 16:00
Reading place: Defensa pública a ESEIAAT (Escola Superior d'Enginyeries Industrial, Aeroespacial i Audiovisual de Terrassa) Edifici TR1. C. Colom, 1 08222 Terrassa
Thesis director: COLOM FAJULA, XAVIER | CAÑAVATE AVILA, FRANCISCO JAVIER
Committee:
PRESIDENT: SAURINA CANALS, JOAN
SECRETARI: GARRIGA SOLE, PERE
VOCAL: MARÍN GENESCÀ, MARC
Thesis abstract: On April 29th, 2015, the EU enacted Directive 2015/720, aimed at reducing plastic consumption, promoting the use of reusable bags and encouraging the replacement of single-use plastic bags with biodegradable alternatives. This European legislation was transposed into Spanish law by Royal Decree 293/2018, dated May 18th.This legislation and its accompanying regulations have significantly impacted the transformation sector, forcing it to reinvent itself to continue its activities. This work aims to provide answers to the challenges faced by manufacturers due to this new context, as well as address the needs resulting from it. Distinctive features of this project are its practical nature and industrial scale.A primary objective is to establish the processability and quality windows for recycled post-industrial and post-consumer materials, ensuring the production of a final product with predefined quality standards. The study examines three types of polyethylene: virgin, post-industrial, and post-consumer. Each type undergoes a combined cycle simulating an industrial recycling process, with post-industrial material being processed up to twelve times and post-consumer material up to four times. This methodology of cyclic processing supports the principle of circularity in sample characterization.For each cycle, involving extrusion and recycling, the study examines micro and macroscopic changes, analyzing morphological and structural changes (using DSC, TGA, GPC, and FTIR techniques) and the evolution of mechanical properties (tensile strength, elongation at break, tear resistance, impact resistance (dart test), and colorimetric changes).At the microstructural level, two types of crystalline structures are observed, and they evolve differently through the processing cycles due to the thermo-oxidative degradation phenomena that occur along the process. The changes include a reduction in crystallinity due to the breakdown of more linear and less branched chains, and an increase in cross-linking among more branched structures. These microstructural changes affect post-industrial and post-consumer recycled polyethylene differently.Macroscopically, tear resistance is the most critical property affected during the recycling cycles, decreasing by up to 40% from the initial value and potentially becoming the main limitation for the successive reuse of these polymers.In line with the previously mentioned regulations, biodegradable polymers are another focus of interest. The study examines biodegradable compostable polymers used to manufacture single-use bags. A secondary objective is to determine how long these biodegradable polymers retain their usability properties under standard storage conditions, analyzing the samples over twelve consecutive months.Macroscopically, a progressive loss in tensile, elongation, and impact properties is the most significant phenomenon. Microscopically, two degradation mechanisms—hydrolysis and thermo-oxidation—are observed, both occurring in the amorphous phase of the material.The study concludes that the tested bags have a shelf life of over twelve months under standard storage conditions.
- DE LAMA ODRÍA, MARÍA DEL CARMEN ELIZABETH: Applications of hydroxyapatite nanoparticles in the field of biomedicineAuthor: DE LAMA ODRÍA, MARÍA DEL CARMEN ELIZABETH
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 POLYMERS AND BIOPOLYMERS
Department: Department of Chemical Engineering (EQ)
Mode: Normal
Deposit date: 04/10/2024
Reading date: 02/12/2024
Reading time: 11:00
Reading place: Defensa publica EEBE, Sala Polivalente del Edificio A, planta baja, Campus Diagonal-Besòs
Thesis director: DEL VALLE MENDOZA, LUIS JAVIER | DEL VALLE MENDOZA, JUANA MERCEDES
Committee:
PRESIDENT: REINA DEL POZO, MANUEL
SECRETARI: ESPAÑOL PONS, MONTSERRAT
VOCAL: GIMÉNEZ BONAFÉ, JOSEFA
Thesis abstract: In the biomedical field, calcium phosphates have attracted attention due to their biocompatibility and bioactivity. They can be found in different individual phases (e.g., amorphous calcium phosphate, tricalcium phosphate, tetracalcium phosphate, octacalcium phosphate and hydroxyapatite), which vary in composition, Ca/P ratio, crystalline structure, degree of substitution, and properties. Among them, carbonated-low crystallinity and highly crystalline hydroxyapatite (CHAp and HAp, respectively) have principally been used for the design of targeted drug delivery systems (DDS) and implant coatings. As the study of the CHAp and HAp nanoparticles with modified morphologies or with different ionic substituents is commonly focused on the characterization of the systems or on the general analysis of the induced biochemical response, the main objective of the thesis was to extend the knowledge of their biomolecular impact in a variety of cell lines (e.g., tumoral or osteoblastic cell lines). On the first chapter, the potential of CHAp as a carrier for doxycycline (DOX) was evaluated. The system was designed to facilitate the delivery of the antibiotic, repurposed as an antitumoral agent. Moreover, the additive effect of the constituent CHAp ions was demonstrated and the triggered changes in the proteomic and lipidomic profiles were in detail described for the first time by SR-FTIRM. The analysis of TEM micrographs helped to elucidate the morphological variations in the cells treated with CHAp or DOX- CHAp nanoparticles, providing evidence that the mineral systems induce different death mechanisms in the normal and tumoral cell lines. In order to offer a more controlled drug release and to reduce the effect of CHAp components on the normal cells, the nanoparticles were included in electrospun PLA or PLA-PEG fibers in the following chapter. Interestingly, only the PLA-PEG scaffolds allowed the release of antibiotic.In the subsequent chapter, HAp was synthesized with an urchin-like morphology. These nanoparticles were characterized and their potential role as drug carrier of gentamicin was similarly described for the first time. In addition, urchin like nanoparticles with a fluor substitution were prepared and their encapsulation efficiency compared to the values obtained with CHAp and the non-substituted urchin-like systems. The formulated carriers were originally thought as an implant coating that could help prevent the post-surgical infections that remain the principal complication of the orthopedic procedures. The newly developed systems were successfully electrodeposited on the polydopamine/collagen coated implants, followed by a final electrodeposited layer of poly-lysine.
- MATOS RESINA, MARIA LEONOR: New multiresponsive materials platforms for cancer treatment: Smart electroconductive nanoparticles and transdermal devicesAuthor: MATOS RESINA, MARIA LEONOR
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 POLYMERS AND BIOPOLYMERS
Department: Department of Chemical Engineering (EQ)
Mode: Change of supervisor
Deposit date: 07/10/2024
Reading date: 16/12/2024
Reading time: 14:30
Reading place: Anfiteatro PA-3 (Piso -1 do Pavilhão de Matemática) do Instituto Superior Técnico de Lisboa.(13:30 hora de Lisboa - 14:30 hora local)
Thesis director: ALEMAN LLANSO, CARLOS ENRIQUE | ALVES FERREIRA, FREDERICO CASTELO | ARAÚJO ESTEVES, TERESA SOFIA
Committee:
PRESIDENT: ESTRELA RODRIGUES CONDE, JOAO PEDRO
SECRETARI: FERREIRA MORGADO, JORGE MANUEL
VOCAL: GELMI, MARIAL LUISA
VOCAL: VAZAO DE ALMEIDA, HENRIQUE MARTINIANO
VOCAL: ACCARDO, ANTONELLA
Thesis abstract: Cancer remains the leading cause of death in many developed countries. Despite significant progress in cancer treatment many challenges persist, such as severe side effects, damage to healthy tissues due to non-specific drug distribution and high systemic toxicity.Multiresponsive biomaterials systems have emerged as powerful tools for biomedical applications, especially in cancer treatment. This research aims to advance materials approaches to cancer therapy through the development of new electro-responsive materials platforms, incorporating smart nanoparticles (NPs) and transdermal or implantable devices. For example, NPs were used for controlled drug delivery triggered by electrical stimulation, while the devices also responded to secondary stimuli such as acidic pH or to the presence of tumor biomarkers. This combination of external and endogenous stimuli provides enhanced spatiotemporal control over drug delivery.Several therapeutic agents were tested, including an anticancer pentapeptide (CR(NMe)EKA), or drugs like curcumin, and chloramphenicol. The therapeutic agents were loaded into poly(3,4-ethylenedioxythiophene) NPs (PEDOT NPs), which provided the electrical stimuli response. These drug-loaded PEDOT NPs were then incorporated into various biomaterials scaffolds, such as pH-responsive hydrogels and bio-responsive fibers, creating multiresponsive devices. For instance, to achieve a multiresponsive injectable carrier for controlled delivery of the anticancer peptide CR(NMe)EKA, a biocompatible and pH-responsive hydrogel, formed by phenylboronic acid grafted with chitosan, was synthesized and loaded with PEDOT NPs. An electro-chemo responsive hydrogel for chloramphenicol release was prepared by grafting polyacrylic acid onto sodium alginate and encapsulating PEDOT NPs in situ. Additionally, a wireless biomaterials-based electrostimulation system was developed to enable controlled and on-demand release of anticancer drugs, promoting in vitro human prostate cancer cell death. This system utilized curcumin-loaded PEDOT NPs encapsulated in coaxial poly(glycerol sebacate)/poly(caprolactone) electrospun fibers.Overall, this work lays the foundation for designing and developing smarter, more effective biomaterial-based delivery systems for anticancer therapy.Keywords: cancer therapy; controlled drug delivery; electroresponsive nanoparticles; multiresponsive biomaterials; targeting cancer cells.
DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
- ROY, SWASTIKA: Beyond XAI for Trustworthy Federated Learning in 6G Zero-Touch Network SlicingAuthor: ROY, SWASTIKA
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 SIGNAL THEORY AND COMMUNICATIONS
Department: Department of Signal Theory and Communications (TSC)
Mode: Normal
Deposit date: 27/09/2024
Reading date: 16/12/2024
Reading time: 10:00
Reading place: Defensa pública: Edifici B3 Sala de Teleenseyament, ETSETB, Campus Nord
Thesis director: VERIKOUKIS, CHRISTOS | CHERGUI, HATIM
Committee:
PRESIDENT: ALONSO ZARATE, LUIS GONZAGA
SECRETARI: ADELANTADO FREIXER, FERRAN
VOCAL NO PRESENCIAL: SPYROPOULOS, THRASYVOULOS
Thesis abstract: In the approaching era of 6G networks, the necessity for AI-driven zero-touch network automation ishighlighted by the need to support multiple network slices for various use cases. Network slicing (NS),a significant innovation beyond 5G, will depend on AI to effectively manage complicated communicationnetworks. However, the traditional centralized approach for monitoring and controlling raw data facesseveral challenges. Federated Learning (FL) under a decentralized paradigm provides advantages,including improved security, fewer data exchanges, scalability, lower computational costs, and facilitatedfast local analysis and decision-making.Besides, Explainable AI (XAI) plays a crucial role in establishing trust in the AI black boxes throughoutthe deployment, which becomes imperative, mainly when AI is responsible for complicated resourcemanagement and anomaly detection. Stakeholders seek highly performing AI models for efficientresource allocation to ensure fairness, accountability, and compliance. Furthermore, flexible, intelligentmanagement across Radio Access Network (RAN), core network, cloud, and edge is needed to providerevolutionary connectivity in the broader context of the 6G era. The O-RAN Alliance’s push for Open RANarchitecture and AI-driven management tools further supports this vision.The thesis focuses on advancing the efficiency, scalability, transparency, and trustworthiness of 6Gnetworks through innovative approaches in FL, network resource management, and AI/MLmethodologies. The main objectives include reducing SLA violations, enhancing convergence time, andoptimizing computation costs in FL-based analytic engines. Additionally, the aim is to address the trade-off between performance and explainability, ensuring trustworthy predictions and transparent decision-making in the context of 6G network slicing. The proposed approaches leverage closed-loop automation,XAI, and novel federated learning models to achieve these goals while aligning with the demands andchallenges of the evolving 6G O-RAN landscape.First, A cloud-native SLA-driven FL model has been proposed to improve scalability and performance fornon-IID data at the RAN-Edge. It also demonstrated its superiority in reducing SLA violations andcomputation costs compared to different FL baselines.Second, inspired by closed-loop automation and XAI, we have designed an Explainable Federated DeepLearning (FDL) model to predict per-slice RAN dropped traffic probability, prioritizing explainabilitymetrics and outperforming baseline models.Third, we have proposed an explanation-guided in-hoc federated learning (FL) approach to address thetrade-off between AI performance and explainability for trustworthy 6G network slicing resourcemanagement in a RAN-Edge setup.Fourth, motivated by closed-loop (CL) automation and explanation-guided learning (EGL), we havepresented an explanation-guided federated learning (EGFL) scheme to ensure trustworthy predictionsand enhance model fairness.Lastly, addressing critical resource provisioning challenges among multiple virtualized base station (vBS)instances in the 6G O-RAN landscape, we have proposed a Federated Machine Reasoning (FLMR)framework to optimize CPU demand prediction for vBS, ensure transparent AI decisions and showcasesuperior performance compared to the DeepCog baseline.These methods advance 6G network scalability, efficiency, and transparency, contributing to developingAI-driven, trustworthy network management solutions.
- WANG, YIAN: Detection and Dynamic Update of Landslide Deformation in Plateau Reservoir Area Using Time Series InSARAuthor: WANG, YIAN
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 SIGNAL THEORY AND COMMUNICATIONS
Department: Department of Signal Theory and Communications (TSC)
Mode: Change of supervisor + Article-based thesis
Deposit date: 31/10/2024
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: MALLORQUI FRANQUET, JORDI JOAN | GONG, JIANYA
Committee:
PRESIDENT: LI, ZENGYUAN
SECRETARI: DONG, JIE
VOCAL: WAN, CHANGCHENG
VOCAL NO PRESENCIAL: BROQUETAS IBARS, ANTONI
VOCAL NO PRESENCIAL: ZHAO, FENG
Thesis abstract: Spaceborne radar interferometry (InSAR) has shown significant advantages in extracting surface deformation information of landslides. However, the steep terrain, dense vegetation coverage, and rapidly changing meteorological conditions in complex reservoir areas pose substantial challenges to the application of time-series InSAR technology for landslide deformation detection and dynamic monitoring. Therefore, achieving reliable, efficient, and high-precision InSAR-based landslide deformation detection and dynamic updates in complex mountainous regions has become a research hotspot in the fields of radar remote sensing and engineering geology. This paper addresses the aforementioned challenges and conducts theoretical algorithm development and applied research, with the main research contents and contributions including the following:1) InSAR Applicability Estimation Method for Landslide Detection.2) Sequential Optimization Method for Distributed Scatterer Polarimetric Interferometric Phase. 3)Tropospheric Delay Phase Correction for Mountainous InSAR Considering Spatial Heterogeneity. 4) Automatic Detection and Dynamic Cataloging Method for Large-Scale Active Landslides Using InSAR.
DOCTORAL DEGREE IN SUPPLY CHAIN AND OPERATIONS MANAGEMENT
- ANICH GUTIÉRREZ, NICOLAS ENRIQUE: Metodología para el rediseño de cadenas de suministro multinegocioAuthor: ANICH GUTIÉRREZ, NICOLAS ENRIQUE
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 SUPPLY CHAIN AND OPERATIONS MANAGEMENT
Department: Department of Management (OE)
Mode: Normal
Deposit date: 27/09/2024
Reading date: 02/12/2024
Reading time: 11:00
Reading place: Aula 28.8 - ETSEIB- UPC - Avda. Diagonal, 647, Barcelona
Thesis director: MATEO DOLL, MANUEL
Committee:
PRESIDENT: DE CASTRO VILA, RODOLFO
SECRETARI: LUSA GARCIA, AMAIA
VOCAL: BENEDITO BENET, ERNEST
Thesis abstract: Each supply chain arises in response to a new need, whether due to new customer groups or new forms of communicationwith customers. As reality evolves, new supply chains are designed, many of them similar to those existing. Currently, several supply chains of the same organization can be managed independently, either due to different customer groups or different marketing channels. This is a multi-business case. In turn, changes in the environment lead managers to modify the configuration of supply chains, which is a redesign. In addition, academic literature deals extensively with the design of supply chains, while redesign is limited; likewise, multi-business reconfiguration is not frequent.In this work, a methodology is developed for redesigning several supply chains corresponding to several businesses in a network structure called REDNURS (Re-Design Network Under Risk and Synergies). This methodology, based on asuccession of steps, determines the stages and levels of complementarity of a pivot chain with respect to others. The effects of synergies do not only include simple complementarities of activities, but also they take into account the different decision levels (strategic, tactical, and operational) and dimensions (static and dynamic) in supply chains.To this end, the MESHAV (Methodology of Evaluated Synergies Horizontally and Vertically) is developed. Its objective is, on the one hand, to achieve the measurement of synergistic sources and obtain a Horizontal Synergistic Factor. On the other hand, the dynamic behavior must be evaluated, which is achieved through a Vertical Synergistic Factor derived from the results obtained in its structural phase. All these structural and dynamic changes allow obtaining the Global Synergistic Factor of the network, the result of which is reflected in an a priori redesign of each multi-business chain.The use of qualitative and quantitative tools allows obtaining, from an a priori solution provided by MESHAV, a group of different types of architectures, which consider inventory levels, processing times, costs and service levels. To do this, algorithms are developed to optimize the redesign of this multi-business network. For which, static models are used for the structural dimension and dynamic models for the evolution of flows. The tools used are, first of all, simulation models in conjunction with AHP (Analytic Hierarchy Process) and TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) systems. The simulation allows analyzing the dynamic dimension; from a set of scenarios and configurations, dynamic indicators such as inventory times and levels are obtained. This result is used as the starting data for the resolution of the static dimension using linear programming models, either for the manufacturing stage or for the distribution stage.This work demonstrates the applicability of the research by developing the redesign of three supply chains in the pharmaceutical sector of a South American country and additionally the redesign for a global group that manufacturesautomobiles of different brands.
DOCTORAL DEGREE IN SUSTAINABILITY
- ESPINOZA AGUILAR, YURI PATRICIO: De la explotación extractiva a la recuperación ambiental, paisajes mineros su transición. Portovelo – EcuadorAuthor: ESPINOZA AGUILAR, YURI PATRICIO
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 SUSTAINABILITY
Department: University Research Institute for Sustainability Science and Technology (IS.UPC)
Mode: Normal
Deposit date: 30/09/2024
Reading date: 29/11/2024
Reading time: 11:00
Reading place: Defensa pública Aula DECA - B1-005.
Thesis director: MAYORGA CÁRDENAS, MIGUEL YURY
Committee:
PRESIDENT: GALINDO DÍAZ, JORGE ALBERTO
SECRETARI: PESOA MARCILLA, MELISA
VOCAL: ALVAREZ PALAU, EDUARD JOSEP
Thesis abstract: In Ecuador, extractive exploitation constitutes one of the most relevant productive sectors due to its capacity to generate economic resources, at the same time mining has often caused severe environmental impacts, this qualification can be a consequence of both processes with little technological development, as well as the geographical characteristics and the environment in which the gold deposits are located. This study is based on the importance of the environmental, social and economic transformation that gold extraction has caused over time in Portovelo, a canton located in the south of Ecuador in the province of El Oro and considered the first mining center in the country.We live in a time in which humanity has given obvious importance to the protection of the environment, in the processes of extractive exploitation the environmental crisis is nothing more than one of the most perceptible symptoms due to the relationship between society and nature, in an unsustainable way. by the change in the natural heritage and culture. The increase in resilience in the face of transformations due to mining activities through the recovery, protection, defense and sustainable use of the mining heritage that is manifested in the landscape as an environmental and cultural indicator of the components, processes and combined characteristics. The recovery of mining landscapes is an element of affinity, identity and manifestation of the diversity that results from the articulation of the mining legacy of the place. However, other factors intervene and have intervened in its modeling, fragmentation and transformation. The infrastructure and equipment associated with the extractive activity, as well as the implantation of ways of life and work totally different from the traditional ones of the mining towns, have left a trace of a cultural nature that is totally perceptible by today's society. In this way, mining landscapes, better or worse preserved, have their own characteristics that vary from other landscapes and in turn have enough differentiating elements that distinguish them from each other.For this research, the phases of extractive exploitation and the socio-environmental consequences to heritage and its transition that have suffered over time as a consequence of population growth, changes in their customs and cultural identity are considered in an integrated manner, through specific methodologies. management with sustainability criteria that contribute to the environmental recovery of the landscape value of all its constituent elements applicable to the acquired legacy. It is important to evaluate in an articulated way the development, growth and planning of the mining heritage of Portovelo, aimed at identifying the aesthetic qualities, state and condition of the historical landscape that determines the constant interaction with the environment, the degree of alteration presented by environmental factors and social identified and its landscape valuation. The model will also be based on bibliographic work and field experimentation, embodied in transition sheets, thematic maps and geographic information systems, which corroborate what was found in the place of study.
- VIDAL MONÉS, BERTA: Unravelling the complexity of food loss and waste: towards sustainable food systems Author: VIDAL MONÉS, BERTA
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 SUSTAINABILITY
Department: University Research Institute for Sustainability Science and Technology (IS.UPC)
Mode: Normal
Deposit date: 27/09/2024
Reading date: 29/11/2024
Reading time: 11:00
Reading place: Defensa pública a - D4-002a - Escola d'Enginyeria Agroalimentària i de Biosistemes de Barcelona (EEABB)
Thesis director: DÍAZ RUIZ, RAQUEL | LOPEZ I GELAT, FELIU
Committee:
PRESIDENT: TORRES MORENO, MIRIAM
SECRETARI: KALLAS CALOT, ZEIN
VOCAL NO PRESENCIAL: VITTUARI, MATTEO
Thesis abstract: Global food systems pose both threats and solutions for sustaining quality of life in our planet. Roughly 40% of the food meant for humans is lost or wasted globally, exacerbating systems unsustainability. Urgent action is needed to reduce food loss and waste, yet progress towards SDG 12.3 is slow. We sustain that a crucial aspect of this challenge lies in an incomplete understanding of the problem, particularly at the extremes of the supply chain where significant amounts of food are lost and wasted. Primary production remains understudied while, consumption stages (households and food services) have been extensively analysed yet the issue persists. To foster effective action towards its prevention, the main goal of this thesis is to better characterize the causes lying behind the phenomenon. By doing so I address the three subdomains in need for further comprehension, each of them targeting one specific objective: 1) to characterize the complex nature of food loss at primary production; 2) to identify the dynamics prompting food waste generation in households under extreme event conditions, and 3) to evaluate the role of food waste prevention measures in food services.This thesis consists of three chapters utilizing diverse methodologies. Chapter 1 extensively examines the fruit and vegetable sector in Catalonia, enhancing understanding of food loss complexity through literature review, semi-structured interviews and participant observation. Identified causes were then reviewed and organized using complex-solving methods to recognize root causes. In Chapter 2, an online survey during the COVID-19 lockdown in Spain explores household food waste related behaviours. Chapter 3 proposes a methodological framework for co-designing food waste prevention strategies with canteen staff, measuring food waste at four school canteens in Barcelona. This involves direct measurement and participant observation to inform effective prevention actions based on nudging.This thesis provides evidence-based contributions for action towards food loss and waste prevention. Chapter 1 proved the multifaceted character of food loss, by describing 9 dimensions of causes, revealing and characterising their interconnectedness. In Chapter 2 dynamics related to food waste during the COVID-19 lockdown in households were identified, emphasising the importance of considering personal time and mental health when designing effective prevention measures. Finally, chapter 3 provided evidence on the effectiveness of nudging strategies in preventing food waste in school canteens, especially when co-designed and implemented with canteen staff. These findings are valuable for researchers, policy makers and stakeholders seeking to foster action towards food loss and waste prevention.
DOCTORAL DEGREE IN THEORY AND HISTORY OF ARCHITECTURE
- HEINONEN, PIJATTA MAARIA: Beyond planning: Prefiguring horizontal practices of architecture in the context of autonomous geographiesAuthor: HEINONEN, PIJATTA MAARIA
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 THEORY AND HISTORY OF ARCHITECTURE
Department: Department of History and Theory of Architecture and Communication Techniques (THATC)
Mode: Normal
Deposit date: 25/09/2024
Reading date: 20/12/2024
Reading time: 12:00
Reading place: Face-to-face (Room Sala de Graus. ETSAB. Main floor)
Thesis director: MONTANER MARTORELL, JOSE MARIA | HERNÁNDEZ FALAGÁN, DAVID
Committee:
PRESIDENT: OYON BAÑALES, JOSE LUIS
SECRETARI: FERRERI, MARA
VOCAL: GARCÍA VÁZQUEZ, CARLOS
Thesis abstract: Hegemonic organization of space and architecture as its essential means respond to political and economic intentions whose determination is out of most people’s reach. Representations of dominant practices are embedded in the order and form of space, reaching the spaces and practices of everyday life. The reform of architecture alone has been understood as insufficient in addressing the imbalance of power, indicating the necessity of more fundamental changes in the societal context that architecture depends on. The possible politics of space that would be based on decentralization and inhabitants’ self-determination have been approached theoretically. However, investigations into architectural practices that are, in fact, taking place in counter-hegemonic contexts are few. This study investigated architecture that emerges within the prefiguration of social change, focusing on social movements whose autonomous politics are characterized by horizontal, egalitarian, and non-capitalist principles. The research questions were: What are the characteristics of architectural decision-making, and, what are the characteristics of the architecture carried out in occupied, largely self-built autonomous geographies? The research was based on grounded theory and was guided by simultaneous collection and analysis of data as well as theoretical sampling. Data was collected in three different autonomous geographies in Central Europe. The methods of data collection were participant observation, drawing, mapping, and interviews. The analysis was based on qualitative coding and followed the constant comparative method. The study found first that, in the examined geographies, the collective organization of space is carried out in a direct democratic, transparent manner. Collective decision-making highlights the direct participation of everyone in relevant decisions, from the founding principles of organization to the specific patterns and forms of space. Second, the collective organization of space is voluntary and partial. It is combined with decentralization of decision-making and individual autonomy of intervening in space. Autonomy facilitates a certain freedom to transform space and the social relations implied within, beyond their collective determination. In the examined geographies, spatial organization develops through simultaneous collective and autonomous interventions in a partially non-planned manner. Third, the inhabitants question the property of space and the permanence of architectural form. The open, common, and malleable nature of space enables its transformation according to horizontal lines, referring directly to the inhabitants present. The findings provide new insights into an architecture based on the politics of participation. While the study supports previous theorizations, one of its main contributions is the elaboration of architectural participation as it relates to the shifting negotiation between the individual and the collective. Furthermore, the principal theoretical implication of this study is the questioning and negation of overarching planning that the findings suggest. Instead of exhaustive instruments such as the urban plan, the findings indicate a less invasive idea of coordination-in-space that arises voluntarily from the bottom up. Finally, while questioning certain precepts of normative planning, the study also indicates directions to explore further the possibilities of an indeterminate, horizontal organization of space.
DOCTORAL DEGREE IN URBANISM
- BARRIOS AVALOS, JUAN JOSE: Reestructuración urbana de la Región Hidrológica 36 Nazas - Aguanaval, México: Modelos agroproductivos y sus sistemas hidrográficosAuthor: BARRIOS AVALOS, JUAN JOSE
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: 30/09/2024
Reading date: 22/11/2024
Reading time: 11:30
Reading place: Face-to-face (Room C-B1. ETSAB. Main floor)
Thesis director: FRANQUESA SANCHEZ, JORDI
Committee:
PRESIDENT: LLOP TORNE, CARLOS JUAN
SECRETARI: MENDOZA ARROYO, MARIA DEL CARMEN
VOCAL: SAINZ GUTIERREZ, VICTORIANO
Thesis abstract: Hydrological Region 36 (RH36) is one of the 37 hydrological regions identified in Mexico by the National Water Commission. Within this region lie the basins of the Nazas and Aguanaval rivers, two endorheic rivers in northwestern Mexico. The waters of these rivers have enabled the Metropolitan Area of La Laguna to become a prosperous region with a significant agro-industrial sector. This success was achieved through the regulation of the rivers, primarily the Nazas River, via the construction of dams and canals between 1930 and 1990. However, the control established over the Nazas River through the Lázaro Cárdenas and Francisco Zarco dams, as well as the network of canals in the lower basin, exacerbated the loss of the Mayrán Lagoon at its mouth and led to the disappearance of flow in the lower basin in the area of Torreón, Gómez Palacio, and Lerdo.In the lower basins of RH36, there is significant water stress resulting from the overexploitation of major aquifers and the reduced availability of water resources due to the impacts of climate change. This research is based on the hypothesis that the severe water stress is partly caused by the disconnection between the regional infrastructure for water storage and distribution, agricultural irrigation systems, rural and urban populations, and their productive agricultural areas. Additionally, it is argued that hydraulic infrastructures have been planned without considering the regional urban context of the lower basin and its logical dimensions, leading to disruptions in the ecological matrix and the organization of rural populations.The research employs a basin approach to define the scope of the study. It sustained that for the restructuring of populations and the potential fluvial restoration of the Nazas and Aguanaval rivers, it is essential to understand the organization of all communities within the geographical boundaries. Each of the 33 sub-basins that make up RH36 are subject to an in-depth analysis of its urban and rural fabric. In addition to populations, the study of agricultural areas, hydraulic infrastructure, and road networks is a fundamental part of this basin approach.The thesis is organized into four chapters. The first chapter outlines the methodology, hypothesis, objectives, and the general structure of RH36. It also includes references to water storage structures in various contexts with geographical conditions similar to RH36. The second chapter is an atlas aimed at constructing morphological information about the 33 sub-basins of the region, including their urban, rural, and agricultural areas. This atlas is one of the main contributions of the research and serves as a prelude to Chapters III and IV. Chapter III explores global references on river restoration and dam removal, which serve as a foundation for Chapter IV, where the strategic approach to fluvial restoration in RH36 is presented.Finally, the research presents conclusions based on a thorough analysis of the urban and rural fabric, the hydrographic network, and hydraulic infrastructure. It argues that hydraulic infrastructures located in the urban-rural transition zones of intermediate cities within RH36 can provide ecosystem services and promote ecological and productive balance in the region. Furthermore, it maintains that the hydrological restoration in the lower courses of the Nazas and Aguanaval rivers is directly dependent on the restructuring of hydraulic infrastructure in both urban and rural populations throughout Hydrological Region 36.
- FIALLO CARDONA, GLORIA CAROLINA: INTERACCIONES LÍQUIDAS. Dibujar el agua de la ciudad de BogotáAuthor: FIALLO CARDONA, GLORIA CAROLINA
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: 24/10/2024
Reading date: 26/11/2024
Reading time: 16:30
Reading place: Face-to-face (Room Sala de Grados ETSAB. Main floor) Videoconference: meet.google.com/fuy-hpct-jsp
Thesis director: SABATE BEL, JOAQUIN | PESOA MARCILLA, MELISA
Committee:
PRESIDENT: LLOP TORNE, CARLOS JUAN
SECRETARI: GALLEGO PICARD, ELISA
VOCAL: LONGHIN, ELENA
VOCAL NO PRESENCIAL: OSORIO GUZMAN, ANA MARIA
VOCAL NO PRESENCIAL: MEDINA ACOSTA, MERCEDES
Thesis abstract: Bogotá, located in a lacustrine savanna surrounded by páramos and wetlands, has been shaped throughout its history by its relationship with water. From the muisca camellones to modern urbanization processes, the city has integrated rivers, canals, and streams into its urban fabric. Water, “sie,” has been the subject of study from various disciplines, highlighting its environmental, economic, and social significance. However, the traditional approach in Bogotá has focused on water supply and risk control, often leading to overexploitation of the resource and a reductionist representation on maps, where water is depicted as a simple blue line, disconnected from its context, resulting in a loss of environmental quality.In light of the current climate crisis, it is imperative to reexamine the relationship between water and territory with a more holistic and sensitive approach, especially from an environmental perspective. This research is based on the hypothesis that Bogotá acts as an interface between páramos and wetlands, revealing the need for new interpretations of how water interacts with the territory. The main objective is to explain the interactions between water and the city of Bogotá, shedding light on the role of water in the city through two epistemological approaches: water as a subject of rights and as a network agent.The thesis uses hydrocartographies, combining data analysis techniques with interpretative drawings and empirical observations to provide a comprehensive view of the different representations of water and its influence on territorial configuration. The proposed trans-scalar and multidimensional approach allows questioning traditional analyses and exploring new solutions based on an understanding of water’s natural cycles.We conclude that in Bogotá, water acts as a dynamic agent in the spatial dialogue between the urban environment and bodies of water, redefining boundaries through a trans-scalar approach that challenges traditional limits and proposes a more harmonious integration of territorial components. Since no cartography is definitive and each representation reflects processes in constant flux, the study suggests a new way of appreciating the territory’s attributes, promoting a reconciliation between water and the city while emphasizing the constancy of change, the fluidity. This deeper understanding highlights the need to adapt urban planning to consider water not only as a static resource but as a subject of rights and an agent in constant influence over urban development. The vision of Bogotá as a city of wetlands, interacting with páramos and basins, would make water dynamics visible in urban planning, challenging territorial models that have ignored its presence.
Last update: 21/11/2024 05:45:30.