Public display of deposited theses

DOCTORAL DEGREE IN APPLIED MATHEMATICS

• LAMAS RODRÍGUEZ, JOSÉ: Oscillatory motions, parabolic orbits and collision orbits in the planar circular restricted three-body problem.
  
  Author: LAMAS RODRÍGUEZ, JOSÉ
  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 APPLIED MATHEMATICS
  Department: School of Mathematics and Statistics (FME)
  Mode: Normal
  Deposit date: 09/05/2025
  Deposit END date: 22/05/2025
  Thesis director: MARTINEZ-SEARA ALONSO, MARIA TERESA | GUARDIA MUNARRIZ, MARCEL
  Thesis abstract: The planar circular restricted three body problem (PCRTBP) models the motion of a massless body under the attraction of other two bodies, the primaries, which describe circular orbits around their common center of mass. In a suitable system of coordinates, this is a two degrees of freedom Hamiltonian system. The orbits of this system are either defined for all (future or past) time or eventually go to collision with one of the primaries. For orbits defined for all time, Chazy provided a classification of all possible asymptotic behaviors, usually called final motions.By considering a sufficiently small mass ratio between the primaries, we analyze the interplay between collision orbits and various final motions and construct several types of dynamics.We show that orbits corresponding to any combination of past and future final motions can be created to pass arbitrarily close to either one of the primaries. In particular, we also establish oscillatory motions accumulating to collisions. That is, oscillatory motions in both position and velocity, meaning that as time tends to infinity, the superior limit of the position and velocity is infinity while the inferior limit of the distance to one of the primaries is zero. Additionally, we construct arbitrarily large ejection-collision orbits (orbits which experience collision in both past and future times) and periodic orbits that are arbitrarily large and get arbitrarily close to either one of the primaries. Combining these results, we construct ejection-collision orbits connecting both primaries.
  

DOCTORAL DEGREE IN ARTIFICIAL INTELLIGENCE

• GUTIÉRREZ MONDRAGÓN, MARIO ALBERTO: Exploring the Dynamics of the beta2-Adrenergic Receptor: Insights from Explainable AI in GPCR Research
  
  Author: GUTIÉRREZ MONDRAGÓN, MARIO 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 ARTIFICIAL INTELLIGENCE
  Department: Department of Computer Science (CS)
  Mode: Normal
  Deposit date: 12/05/2025
  Deposit END date: 23/05/2025
  Thesis director: VELLIDO ALCACENA, ALFREDO | KÖNIG, CAROLINE LEONORE
  Thesis abstract: G-protein coupled receptors are transmembrane proteins that serve as critical mediators between extracellular signals and intracellular responses. These highly dynamic entities orchestrate a wide array of cellular processes in response to various stimuli, including hormones, neurotransmitters, and environmental signals. Due to their versatility and central role in cellular communication, GPCRs are prime pharmacological targets for treating a wide spectrum of diseases, ranging from diabetes and Alzheimer's to various forms of cancer. Despite significant advances in understanding their dynamic conformational landscapes, the precise molecular mechanisms underlying their transient and intricate shifts, especially upon ligand binding, remain obscured by the complexity of their structures. This poses substantial challenges to the elucidation of the processes that govern their signaling mechanisms. In this thesis, we leverage the wealth of information generated by Molecular Dynamics simulations through advanced Machine Learning models to help decode the complex conformational landscape of GPCRs. A crucial step in our approach involves transforming the raw MD data into structured formats that are more suitable for analysis. Deep Neural Networks, known for their strength in capturing intricate relationships within large datasets, form the backbone of the thesis. When coupled with state-of-the-art explainability techniques, these models not only produce accurate classifications, but also reveal molecular mechanisms that drive the behavior of GPCRs.Our goal extends beyond building reliable models for classification. We aim to reveal critical patterns and insights that deepen our understanding of GPCR dynamics. By focusing on the beta2 -adrenergic receptor, our aim is to improve the interpretation of receptor behavior while creating a reliable framework for broader applications in proteomics.
  

DOCTORAL DEGREE IN BIOMEDICAL ENGINEERING

• GÓMEZ GONZÁLEZ, SÍLVIA: Surface modification treatments to enhance the performance of titanium backplate in keratoprosthesis
  
  Author: GÓMEZ GONZÁLEZ, SÍLVIA
  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 Materials Science and Engineering (CEM)
  Mode: Article-based thesis
  Deposit date: 15/05/2025
  Deposit END date: 28/05/2025
  Thesis director: MANERO PLANELLA, JOSE MARIA | BARRAQUER COMPTE, RAFAEL IGNACIO
  Thesis abstract: The cornea is the outermost layer of the eye, essential for vision as it provides protection and contributes 80% of the eye’s refractive power. Its transparency and lack of blood vessels are key to its function, but its deterioration can lead to corneal blindness. While corneal transplantation is an option, some patients are not candidates, making the keratoprosthesis (KPro) a viable alternative. The KPro, composed of a polymethylmethacrylate (PMMA) optical cylinder and a titanium (Ti) backplate, restores vision but comes with complications such as infections, glaucoma, and failures in corneal integration with Ti, affecting its long-term retention. The lack of bioactivity in Ti hinders corneal tissue adhesion and facilitates infections, which are further aggravated by the immunosuppression of KPro patients, increasing the risk of microbial colonization even years after surgery.This doctoral thesis aims to optimize the retention and performance of the KPro by improving corneal integration and preventing infections through surface modifications of Ti. Three strategies are explored: 1) Coating with a multifunctional peptide platform (PTF), 2) Silver ion (Ag) doping via electrodeposition, and 3) Ion implantation using the Metal Vapor Vacuum Arc (MEVVA) technique with Ag and copper (Cu). The PTF coating combines the cyclic peptide cRGD, which enhances cell adhesion, and the antimicrobial LF1-11 sequence, both anchored to Ti using L-DOPA to ensure efficient one-step functionalization. The cRGD sequence has a more stable structure than linear RGD, making integrin-mediated binding more effective. Although biomolecular coatings have shown promising results, their potential susceptibility to proteolytic degradation has driven the search for new alternatives, such as surface Ag incorporation through electrodeposition techniques. Electrodeposition was optimized by modifying process parameters to ensure uniform Ag distribution, minimizing toxicity while maximizing antimicrobial efficacy without compromising corneal biocompatibility. Finally, to extend ion release over time, antimicrobial surfaces were developed using the MEVVA technique. This method incorporates ions into the base material, offering controlled and sustained Ag release, while the addition of Cu enhances antifungal activity, reducing the risk of both bacterial and fungal infections. Additionally, co-culture assays were conducted to evaluate the antimicrobial efficacy of treated surfaces under more realistic conditions. In conclusion, this doctoral thesis provides innovative solutions to enhance the long-term retention and performance of the KPro, addressing critical challenges such as infection risk and poor corneal tissue integration. By exploring various surface modification strategies, this research successfully demonstrates the potential to improve KPro functionality.
  

DOCTORAL DEGREE IN CHEMICAL PROCESS ENGINEERING

• LOU, YAKE: Bimetallic catalysts for hydrogen production and purification
  
  Author: LOU, YAKE
  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: Change of supervisor
  Deposit date: 16/05/2025
  Deposit END date: 29/05/2025
  Thesis director: LLORCA PIQUE, JORDI | GUO, YUN | JIMÉNEZ DIVINS, NÚRIA
  Thesis abstract: In Chapter 3, CeO2-supported mono- and bi-metallic Co-Rh catalysts prepared by incipient wetness impregnation (IWI) and mechanochemical method (also called ball milling, BM) were used to investigate the DRM reaction. The Co and Rh of fresh catalysts were identified as 5-20 nm nanoparticles and small clusters. Monometallic Rh catalysts showed intimate Rh-CeO2 interaction. The BM method enhanced the catalysts' CO2 activation ability more effectively than the IWI method, resulting in less carbon deposition and graphitization. Overall, the Rh/CeO2-IWI exhibited the best DRM reaction performance among all catalysts due to the moderate interaction between Rh and CeO2, and Rh-Co/CeO2-BM prepared with 50 Hz exhibited a better DRM reaction performance than that of the bimetallic IWI catalyst due to the synergy effect between Co and Rh and CeO2.In Chapter 4, mono- and bi-metallic CoRh catalysts supported on MG70 prepared by IWI and BM methods were synthesized to investigate the DRM reaction. The Co and Rh of fresh MG70-supported bimetallic catalysts were identified as single atoms and small clusters. Besides, the Co and Rh were in intimate contact in the BM sample, which was beneficial to strengthen the interaction between Co and Rh. The stronger interaction between Co, Rh, and MG70 in the BM sample compared with that of the IWI sample helped stabilize smaller metal particle sizes after stability tests. Moreover, the use of bimetallic Co-Rh catalysts prepared by the BM method enhanced the redox properties of MG70-supported Co-Rh catalysts, which helped to decrease carbon graphitization. Overall, the Co+Rh/MG70-BM prepared with 50 Hz exhibited the best DRM reaction performance due to the excellent synergy effect between Co and Rh and the support MG70.In Chapter 5, we investigated the CO-PROX reaction activity of Pt/Al2O3 and a trace amount of Cu-modified Pt/Al2O3 prepared by the strong electrostatic adsorption method. The atomically dispersed Cu2+ was located on Pt nanoparticles, making Pt in a more electrondeficient state and maximizing the Pt-CuOx interface. The more electron-deficient state of Pt helped to weaken the CO adsorption, alleviating the CO poison effect. Besides, the Pt-CuOx interface played a role as an additional O2 activation site, enhancing the O2 activation ability. The CO-PROX reaction of Pt/Al2O3 and Pt-Cu/Al2O3 both followed the HCOO- intermediate route, and the introduction of Cu accelerated the decomposition of HCOO- intermediate. Overall, the addition of Cu enhanced the CO-PROX reaction activity of Pt/Al2O3 in the low-temperature and high-temperature range.In Chapter 6, Bi-modified Pt/Al2O3 catalysts were prepared by a two-step incipient wetness impregnation method to further widen the low-temperature operation window of the CO-PROX reaction. After introducing Bi, Pt nanoparticles tended to be located on Bi2O3 nanoparticles, creating a Pt-O-Bi interface. The redox ability of Pt-x Bi/Al2O3 gradually increased and the chemical state of Pt was gradually in a more electron-deficient state with the increase of Bi loading, therefore improving the O2 activation and decreasing the CO adsorption. Besides, the H2 activation ability was enhanced with increasing the Bi loading. The enhanced H2 activation ability facilitated forming HCOO- intermediates, thus strengthening the promotion effect of H2 at low temperatures. However, the enhanced H2 activation ability played a negative effect at high temperatures due to the enhanced H2 oxidation reaction. Overall, the Pt-0.5 Bi/Al2O3 exhibited the best CO-PROX reaction performance.
  

DOCTORAL DEGREE IN COMPUTATIONAL AND APPLIED PHYSICS

• FLÁVIO DORNELAS, RAMON GUILHERME: Cerámicas ferroeléctricas libres de plomo basadas en BaTiO3 para almacenamiento de energía y otras aplicaciones relacionadas
  
  Author: FLÁVIO DORNELAS, RAMON GUILHERME
  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: Change of supervisor
  Deposit date: 12/05/2025
  Deposit END date: 23/05/2025
  Thesis director: GARCIA GARCIA, JOSE EDUARDO | DE LOS SANTOS GUERRA, JOSE
  Thesis abstract: In this work, barium titanate (BaTiO3) based lead-free ferroelectric ceramics were synthesized and investigated, viewing their applicability in energy-storage devices. The inclusion of the tin (Sn) ion in the perovskite structure of the BaTiO3 (BT) system has been then considered, in order to study the influence of the doping content on the physical properties of the BaTi1–xSnxO3 (BTS) system, where x = 0.03, 0.06, 0.09, 0.12, 0.15 and 0.20). The samples were sintered from the solid-state reaction method from high-purity chemical grades. The structural Properties, investigated from X-ray diffraction and Raman spectroscopy techniques, confirmed the formation of the perovskite structure for all the cases, revealing a phases’ coexistence depending on the analyzed composition. In fact, samples in the 0.03  x  0.09 compositional range evidenced the coexistence between ferroelectric phases with orthorhombic and tetragonal symmetries. On the other hand, the 0.12 and 0.15 compositions revealed the coexistence of the ferroelectric and paraelectric phases, with rhombohedral and cubic symmetries, respectively, whereas the samples with x = 0.20 has shown to be a single-phase composition with the cubic paraelectric characteristic. Therefore, results reveal a strong influence of the Sn4+ cation on the structural and vibrational characteristics of the BT system. On the other hand, the dielectric properties have shown a decrease in the ferroelectric-paraelectric (high temperature) phases’ transition temperature with the increase in the tin content, whereas the low temperature ferroelectric-ferroelectric phases’ transition temperatures increased as the Sn concentration increases. Such a variation could be associated to the influence of both change and coexistence of the involved phases, with the increase of the doping cation. The increase in the Sn concentration also promoted an enlargement in the maximum permittivity peak, indicating a diffuse-type phases’ transition promoted by cationic disorder at the B-site of the perovskite structure. Moreover, the ferroelectric properties allowed for the estimation of the system’s performance for energy storage and solid-state cooling, revealing an optimized storage value for x = 0.15, with ~45 mJ/cm² of recoverable energy and 77% efficiency, as well as an electrocaloric strength coefficient of 0.40 K mm/kV for the 0.09 composition, with these values being higher than those reported in the literature for other similar lead-free systems.
  

DOCTORAL DEGREE IN COMPUTER ARCHITECTURE

• BERTRAN FERRER, MARTA: New approaches for resource management and job scheduling for HEP Grid computing
  
  Author: BERTRAN FERRER, MARTA
  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 COMPUTER ARCHITECTURE
  Department: Department of Computer Architecture (DAC)
  Mode: Normal
  Deposit date: 08/05/2025
  Deposit END date: 21/05/2025
  Thesis director: BADIA SALA, ROSA MARIA | BETEV, LATCHEZAR
  Thesis abstract: The Large Hadron Collider (LHC) ALICE (A Large Ion Collider Experiment) experiment uses grid computing for its extensive data processing and analysis. The ALICE Grid is composed of 48 sites distributed globally, which provide access to over 300,000 CPU cores. This diverse environment presents unique challenges as the computing nodes are very heterogeneous in terms of hardware, resource availability and management policies. This thesis focuses on optimising resource utilisation and job execution within the ALICE Grid in the context of the evolving multicore computing paradigm. The transition from single to multicore slots, combined with the increasing prevalence of multiprocess and multithreaded workflows, requires new resource management approaches.The thesis presents a black-box analysis of the multicore experiment software framework, tracing resource usage and system calls. Multiple sources of overhead were identified, particularly concerning the large amount of short-lived processes spawned by some workflows. To address this, the JAliEn monitoring system was extended and improved to accurately account for the resource utilisation of these short-lived processes. The observations led to modifications on the internal job workflow, resulting in a 47% reduction in the number of deployed processes and a 35% decrease in overall job execution time.For tailoring job requests to the specific characteristics of the executing systems, a model is proposed to estimate job execution times. This model leverages proportionality factors from the execution times on different Grid CPU models and uses them to dynamically scale job requests.To ensure the coherent and controlled utilisation of CPU resources, two approaches are proposed. The first uses CPU pinning and adapts the core selection to the processor architecture, optimising resource allocation for specific workloads. The second uses cgroups v2 sub-partitioning features to set boundaries on job CPU utilisation. The thesis made significant contributions to popular grid batch systems by enabling support for cgroups v2. This integration allowed JAliEn to become the first grid middleware to make use of this powerful resource management technology.When a slot is sub-partitioned to run multiple jobs in parallel, careful resource orchestration is crucial. This thesis presents a module within JAliEn that ensures equitable memory resource distribution among co-executing jobs. This module implements a targeted preemption of resource-intensive jobs to prevent slot overconsumption and ensure that jobs remain within their allocated memory limits.The thesis explores whole-node slot allocations in which JAliEn manages all the resources of a node. This novel scheduling model offers great flexibility and adaptability. To maximise resource usage in whole-node slots, CPU oversubscription was introduced to allow the execution of additional jobs when the running workload does not fully use the available CPU resources. To exploit whole-node allocations and maximise resource utilisation, the thesis proposes the extension of job brokering to consider not only CPU availability but also memory and disk space. Furthermore, the job definition syntax was equipped with new parameters for users to have greater control over resource requests.To sum up, this thesis presents a set of contributions that have substantially improved the efficiency and performance of grid computing within the ALICE experiment. The thesis addresses the challenges emerging from the evolving multicore environment by optimising resource utilisation and improving middleware reliability and observability. All these contributions introduced significant advances to the capabilities of the ALICE Grid, effectively enabling a more efficient data analysis for the LHC experiment.
  

DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING

• GONZÁLEZ CURBELO, MIGUEL ÁNGEL: Plastic Pollution in Marine Ecosystems: Spatiotemporal Assessment in Beach Sediments of Protected Coastal Areas
  
  Author: GONZÁLEZ CURBELO, 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 ENVIRONMENTAL ENGINEERING
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Normal
  Deposit date: 15/05/2025
  Deposit END date: 28/05/2025
  Thesis director:
  Thesis abstract: Plastic pollution has emerged as a critical threat to marine ecosystems, particularly in ecologically sensitive and protected coastal areas. This doctoral thesis presents a spatiotemporal assessment of plastic particle debris, including microplastics, in beach sediments from marine protected areas (MPAs) on the Caribbean coast of La Guajira, Colombia, and marine Special Areas of Conservation (SACs) in Tenerife, Canary Islands, Spain. Fieldwork involved systematic sampling across 13 beaches (seven in La Guajira and six in Tenerife), representing a variety of environmental conditions. The study in La Guajira, the first of its kind in the region, revealed microplastic abundance ranging from 2.4 ± 0.6 to 22 ± 7 microplastics/m2, with concentrations varying statistically by beach use but not significantly between the two sampling periods. Filaments, primarily from fishing activities, were the most prevalent type (38.5%). In Tenerife´s marine SACs, a comprehensive 12-week assessment of macro-, meso-, and microplastics uncovered significant spatial and temporal variability. Playa de Montaña Roja emerged as a notable pollution hotspot, with 64 ± 36 mesoplastics/m2 and 506 ± 364 microplastics/m2. Fragments dominated the samples (80%), especially white and light-colored, indicating their likely origin as secondary particles from consumer products. In both scenarios, the most common polymers detected were polyethylene (PE), polypropylene (PP), and polystyrene, due to their buoyancy in marine environments, which also reflects global trends in production. Further analysis of heavy metal presence in microplastics from Tenerife´s SACs, using microwave-assisted acid digestion and inductively coupled plasma mass spectrometry, identified sixteen elements, including appreciable levels of six Environmental Protection Agency (EPA)-priority heavy metals: chromium, nickel, copper, zinc, cadmium, and lead. Comparative analysis showed a preferential accumulation of chromium, copper, lead, and cadmium in PE fragments over PP pellets, highlighting the role of polymer type. Cadmium concentration was particularly high (105 ± 15 mg/kg) in PE fragments from Playa de Montaña Roja SAC. In summary, this doctoral thesis provides robust empirical evidence on the abundance, spatiotemporal distribution, and characteristics (shape, color, and polymer type) of microplastics in MPAs, along with associated heavy metal concentrations. The findings presented herein not only reinforce the urgency of addressing plastic pollution but also offer practical tools and insights to guide the development of public policies aimed at protecting vulnerable marine ecosystems from microplastic-related threats.
  

DOCTORAL DEGREE IN MARINE SCIENCES

• LÓPEZ MILLÁN, MARILYN: La reconversión de los espacios portuarios, en el puerto de Balboa en el pacífico de Panamá. Propuesta de mejora de la operativa mediante un modelo de optimización.
  
  Author: LÓPEZ MILLÁN, MARILYN
  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: Normal
  Deposit date: 15/05/2025
  Deposit END date: 28/05/2025
  Thesis director: MARTINEZ DE OSÉS, FRANCISCO JAVIER
  Thesis abstract: The coexistence of ports in the Panamanian Pacific with their surroundings requires everyone to have access to the ability to move around in an organized and spontaneous manner. The Port of Balboa, one of the most important centers in Panama's logistics chain and international trade, faces a series of operational challenges due to high demand and the complexity of its workflow. Efficient management of wait times and scheduling for carriers is one of the critical areas that directly impacts productivity and user satisfaction.To develop the studies, various surveys and interviews were conducted to understand the movement times outside and inside the terminal, as well as the arrival and approach of vessels to the terminal.Based on this diagnosis, a mathematical optimization formula was developed that took into account various factors, such as cargo volume, type of transport, truck characteristics, and the availability of port resources. The formula sought to reduce carrier wait times by assigning appointments more efficiently and in line with the port's actual capacity. To achieve this, optimization and mathematical programming techniques were used, which allowed for the establishment of a more precise methodology for appointment management.In this context, this research focused on developing a mathematical solution. Based on the results, a custom mathematical model was developed in Python that could be extrapolated to other terminals. This model seeks to generate operational efficiency and minimize long wait times outside the facilities. This model also fosters a positive relationship with the surrounding community.This research demonstrates the feasibility of applying optimization methods and advanced technological tools in ports and logistics terminals, contributing to improved appointment management and optimized wait times. The successful implementation of this formula at the Port of Balboa could be replicated at other ports and logistics points, offering a scalable solution to optimize service to carriers, reduce operating costs, and improve efficiency in international trade.The findings highlight that establishing an adequate flow to serve truck drivers by scheduling appointments to minimize wait times minimizes both the average truck service time and the total service time for all trucks during the day. Furthermore, queques and congestion around port facilities are eliminated.
  

DOCTORAL DEGREE IN MATERIALS SCIENCE AND ENGINEERING

• RIU PERDRIX, GUIOMAR: Dry-electropolishing of WC-Co cemented carbides: Chemical, microstructural and mechanical characterization
  
  Author: RIU PERDRIX, GUIOMAR
  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: 06/05/2025
  Deposit END date: 19/05/2025
  Thesis director: ROA ROVIRA, JOAN JOSEP | LLANES PITARCH, LUIS MIGUEL
  Thesis abstract: WC-Co cemented carbides are widely used in industry, particularly for cutting tools, due to its exceptional combination of mechanical properties. They are composites consisting of tungsten carbide (WC) particles embedded within a cobalt (Co) metallic binder. This microstructural assemblage provides a unique combination of hardness, wear resistance, and fracture toughness. However, these properties can degrade at high temperatures (>500 ºC) due to corrosion sensitivity. To address this limitation, protective coatings, such as titanium aluminium nitride (TiAlN) or titanium silicon nitride (TiSiN) are frequently applied, enhancing performance under high-temperature loading.Grinding is the most conventional post-processing technique used to achieve the final geometry and dimensional tolerances of WC-Co components. However, this method impacts surface integrity, inducing defects like voids, cracks, high roughness (0.2 - 0.6 µm), phase transformations in the metallic Co binder, and compressive residual stresses, extending up to 10-20 µm in depth. Accordingly, removal of the damaged layer though polishing is commonly advised.In recent years, a new dry-electropolishing technology has emerged for metallic alloys, allowing precise defect reduction and surface improvement. Unlike conventional electropolishing, which uses liquid electrolytes, dry-electropolishing uses solid porous polymeric particles (ion exchange resins) filled with an electrolytic medium. This method selectively removes material layer-by-layer from surface irregularities, reducing roughness and improving surface quality.This industrial Ph.D. thesis focus on the development of a novel dry-electrolyte specifically tailored for electropolishing WC-Co composites using DryLyte® Technology. The research explores the underlying polishing mechanisms, optimizes electrical parameters, and identifies key chemical reactions involved in the process. Results demonstrate that this process effectively eliminates surface defects, reduces roughness, and preserves the WC-Co microstructure, avoiding Co leaching and WC embrittlement.A comparative microstructural and mechanical analysis was conducted, evaluating various shaping and finishing methods, including grinding, electrical discharge machining (EDM), conventional polishing, and dry-electropolishing. The findings reveal that, while grinding and EDM are widely used, they generate surface defects such as micro-cracks, porosity, and harmful oxides. Conventional polishing improves surface roughness but removes hundreds of microns of material and fails to preserve compressive residual stresses, thereby diminishing the mechanical performance of the system. Conversely, dry-electropolishing precisely eliminates deformed layers, achieves smooth surfaces between phases, and retains beneficial compressive residual stresses.The thesis further explores the industrial applications of this technology, such as cutting edge preparation for WC-Co end-mill tools. Previous studies have demonstrated that an optimal edge preparation increases tool life. The results of this research confirm that dry-electropolishing can fine-tune the cutting edge radius, refine micro-geometric parameters, reduce roughness, and eliminate manufacturing-induced defects. A direct correlation between polishing time and micro-geometric parameters is established, showing rapid changes within the first three minutes, followed by stabilization.Additionally, the research investigates the stripping of worn TiAlN/TiSiN coating on WC-Co substrates to extend their operational lifespan and reduce costs. This process removes the films precisely, leaving an oxide surface layer without compromising the substrate microstructure. The process demonstrates a linear relationship between polishing time and remaining coating thickness, ensuring a controllable, efficient, and homogeneous method.
  

DOCTORAL DEGREE IN PHOTONICS

• BATLLE PORRO, SERGI: Near-field photocurrent in correlated 2D moiré materials
  
  Author: BATLLE PORRO, 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 PHOTONICS
  Department: Institute of Photonic Sciences (ICFO)
  Mode: Normal
  Deposit date: 14/05/2025
  Deposit END date: 27/05/2025
  Thesis director: KOPPENS, FRANK | STEPANOV, PETR
  Thesis abstract: Since the discovery of graphene, two-dimensional (2D) materials have garnered significant attention from the condensed matter physics community owing to their potential to engineer new physical, optical, and mechanical properties. The 2D material class now includes insulators (hexagonal boron nitride, hBN), semiconductors (transition metal dichalcogenides, TMDs), superconductors (NbSe2), topological insulators (Bi2Te3), and ferromagnets (CrI3). Beyond their inherent properties, layered materials allow for new characteristics through vertical stacking. Recent developments have led to the discovery of moiré materials, in which electronic properties are significantly altered by twisting adjacent 2D layers.The discovery of superconductivity in magic-angle twisted bilayer graphene (MATBG) marked a milestone in moiré physics, initiating a rapidly growing field. The resulting phase diagrams of other high-Tc superconductors, MATBG, serve as a platform for exploring highly tunable strongly correlated states. At a twist angle of approximately 1.1°, the "magic angle,” MATBG shows significant band flattening near the Dirac points, reducing the Fermi velocity and making the kinetic energy smaller than the repulsive Coulomb interactions. This results in superconductivity and various emergent phases dominated by many-body physics, including correlated insulators, orbital magnetism, nematic orders, and topological states.Moiré materials with large superlattice unit cells facilitate the exploration of strongly correlated phenomena at low charge carrier densities. Local back-gate electrodes enable capacitive tuning between strongly correlated states in-situ, a unique feature not available in other high-Tc superconductors. Advances in scanning probe techniques have allowed researchers to determine local properties at the sub-nanometer scale. Scattering-type scanning near-field optical microscopy (s-SNOM) is particularly suited for exploring MATBG because it can measure scattering and photovoltage signals at the nanometer scale while simultaneously probing mesoscopic electron transport. Utilizing a groundbreaking cryo-near-field nanoscopy method, we will conduct s-SNOM measurements at cryogenic temperatures (as low as 8 K) to assess the optical and photovoltage near-field responses. This approach employs energies in the mid-infrared (MIR) and terahertz (THz) ranges, which align with the anticipated optical transition energies in the band structures of these materials. The primary objectives of this thesis are to ascertain the pertinent optical and thermoelectric coefficients in twisted moiré materials, evaluate the impact of inhomogeneities through gate-tuned near-field photovoltage and optical measurements, visualize correlated phenomena and broken symmetry states, and comprehend the nature of dephased signals in various measurements. This dissertation seeks to highlight crucial advancements in quantum phases, quantum nano-optoelectronics, and thermoelectricity, while supporting interest in unresolved questions, such as the characteristics of low-temperature correlated states. Additionally, it outlines future objectives for near- and far-field photovoltage experiments.
  

DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS

• CARREÑO MEGIAS, XAVIER: Ground-based GEOSAR system using DVB-S/S2 signals of opportunity and FPGA based correlators
  
  Author: CARREÑO MEGIAS, XAVIER
  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: 06/05/2025
  Deposit END date: 19/05/2025
  Thesis director: BROQUETAS IBARS, ANTONI
  Thesis abstract: The SAR satellite missions from Geostationary Orbits (GEOSAR) offer short revisit times of less than 24 hours, which are essential for monitoring fast-evolving phenomena. A first mission has recently been launched in China, and other missions are being studied or proposed in Europe and the USA, with applications ranging from water cycle monitoring to terrain stability assessment. All of these missions share the need for precise orbit determination at Geostationary Orbits (GEO) to enable the formation of well-focused SAR images.By employing Field-Programmable Gate Array (FPGA) technology, digital correlators have been designed to be used in an interferometric orbit determination system. The system has been validated for obtaining orbital estimates using phase observables from the correlator outputs, which can be used to determine the satellite's trajectory. The implemented system tracks TV broadcasting telecommunication satellites, using the transmissions as signals of opportunity (SoOp). Urban reflectors are utilised to form large interferometric baselines with respect to the developed receiver.Precise orbital determination is crucial for Synthetic Aperture Radar (SAR). Simulation studies were conducted for a monostatic configuration and a ground-based bistatic configuration to assess the impact of orbital parameter estimation errors on SAR image focusing. An autofocusing technique based on entropy minimization optimisation has been studied to improve the focusing of the GEOSAR images affected by residual orbital errors, allowing for the relaxation of orbit precision requirements to the order of hundreds of metres. Using the same transmitters of opportunity as in the interferometric system, a ground-based SAR (GB-GEOSAR) passive system has been designed and implemented. A multichannel coherent receiver is employed to capture echo data from a close by urban scene. A range compression module, based on the design of the interferometric correlators, is employed to process the echo data by correlating it with the main satellite signal, which acts as a reference for the matched filter process. Azimuth compression, based on the orbital data from the interferometric system, is then applied to obtain SAR-focused images. These images can be used to study GEOSAR concepts and serve as proof of concept for the capabilities of a passive system, which could be employed for monitoring local regions with low deployment costs.Interferometric and polarimetric techniques can be applied to GB-GEOSAR images, which could be used in topographic or earth deformation mapping and surface type classification. An experimental evaluation based on images of urban and mountainous areas near the university campus has enabled the identification of the challenges, potentials, and limitations of the developed system.
  

DOCTORAL DEGREE IN SUSTAINABILITY

• RESTREPO MESA, MARIA DEL PILAR: Metodología de articulación de actores públicos, privados, academia y ciudadanía como esquema de gobernanza del agua en cuencas hídricas urbanas latinoamericanas
  
  Author: RESTREPO MESA, MARIA DEL PILAR
  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: Article-based thesis
  Deposit date: 06/05/2025
  Deposit END date: 19/05/2025
  Thesis director: MORATO FARRERAS, JORDI | CADENA GAITÁN, CARLOS
  Thesis abstract: This research work, initiated in 2018, proposes a methodology for the articulation of public, private, academic and citizen actors as a water governance scheme in Latin American watersheds. It combines technical knowledge with the local knowledge of the communities settled in the territory, transcending the limitations of governmental periods and promoting the appropriation of the actors through co-creation exercises to achieve sustainable actions that improve the conditions of the water resource, strengthening trust, reciprocity and cooperation.The methodology was applied in the watersheds of La Iguaná, Doña María and Santa Elena streams, located in the Aburrá Valley, whose core municipality is Medellín, Colombia. This process was part of the Alliance for the Climate and Health Emergency in the Aburrá Valley, in which entities such as CORANTIOQUIA and the Aburrá Valley Metropolitan Area, environmental authorities, the District of Medellín, the Metropolitan Technological Institute, the Polytechnic University of Catalonia, the Barcelona City Council, EPM as the Public Utilities Company, Pork Colombia (a private sector entity) and the settled communities participated. Seven years later, the actions in the watersheds have become more dynamic and the communities have joined together in the SOS Watershed Network, where they exchange knowledge and lessons learned. This shows that it is possible to consolidate a roadmap through co-creation exercises that can be implemented in the short, medium and long term. Following the ideas of Ostrom (1997) and Scharmer (2024), the process includes knowing the limits and natural supply of the territory, establishing a dialogue with small groups to lead from the emerging future in terms of ecosystem regeneration, homologating concepts, views and interests, knowing the actions carried out in the past, mobilizing resources according to the capacities and roles of each one with a view to achieving the common objective. This contributes to consolidating water governance, which will translate into the necessary water security for the population. Environmental observatories are key tools for co-creation among basin stakeholders. It is necessary to identify the most appropriate type of observatory for each basin and implement a permanent updating scheme to guide decision making, through co-creation schemes with all stakeholders, prioritizing the most urgent actions. The democratization of information, the active participation of citizens, the diversity of stakeholders involved, continuous monitoring, and regulatory frameworks are key aspects that an environmental observatory should have in order to consolidate water governance. The focus groups and the workshop on Barriers that limit Water Governance showed that the main barriers are: high levels of distrust among the different stakeholders, difficulty in working towards a common goal, particular interests, legal limitations to enhance collaborative work, lack of knowledge about what a watershed is and the lack of accurate information to make decisions that improve the environmental and social conditions of the watersheds towards water security. The methodology integrates local knowledge with technical rigor through dialogues where everyone values each other's contribution, visualizing together the priorities in each watershed. This constitutes a conscious leadership exercise that seeks to transcend the mechanisms implemented over time, motivating sustained and inclusive processes. It is hoped that, given the similarity of socio-environmental contexts in Latin America, it can be replicated in other regions, strengthening water governance schemes and environmental justice, highlighting the importance of water within the water-energy-food nexus, as a vital element for human survival.
  

DOCTORAL DEGREE IN URBAN AND ARCHITECTURAL MANAGEMENT AND VALUATION

• PIASEK VINOCUR, GONZALO: Vulnerabilidad + regeneración = población en peligro de expulsión. Aprendizajes para una regeneración urbana inclusiva
  
  Author: PIASEK VINOCUR, GONZALO
  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 URBAN AND ARCHITECTURAL MANAGEMENT AND VALUATION
  Department: Department of Architectural Technology (TA)
  Mode: Article-based thesis
  Deposit date: 13/05/2025
  Deposit END date: 26/05/2025
  Thesis director: GARCIA ALMIRALL, MARIA PILAR | MUXI MARTINEZ, ZAIDA
  Thesis abstract: This proposal is within the framework of a research project ‘Socio-spatial indicators for the improvement of building stock in vulnerable areas. Action criteria for the cases of the Metropolitan Areas of Barcelona and Bilbao’ (RE-INHABIT RTI2018-101342-B-I00), financed by the National Research Agency (AEI for its Spanish name). This framework project’s hypothesis is that most dense Spanish and European cities face the growing problematic of urban soil shortage, making it necessary to improve the existing housing stock.This work, framed within the ‘Urban and Architectural Management and Valuation’ Doctoral Program from Barcelona’s School of Architecture (Polytechnic University of Catalonia), aims to study the urban regeneration phenomenon in areas of high vulnerability from a broad perspective, taking into consideration both the physical and social components of the neighborhoods. Starting from the hypothesis that ‘most organized neighborhoods get more work and financial help’ – idea that was repeated regularly throughout a set of interviews – the main objective is to study the impact of urban regeneration policies in vulnerable areas of Barcelona at a social, physical-urban and socioeconomic level, in their links with the organizational component of the territories.If most organized neighborhoods receive most aid, it is interesting to ask what it means to be a more organized neighborhood; then, which are the conditions that make certain areas of the city promote higher levels of social interaction. Thus, based on the construction of a socio-residential vulnerability index, in its relation with another index of social capital (depicting the levels of social interaction) and another one of social infrastructure (focusing on the characteristics of spaces of social encounter) applied to the city of Barcelona, we seek to provide knowledge on innovative ways of studying and intervening with comprehensive policies focusing on the most disadvantaged areas of our cities. Likewise, a mapping and critical analysis of the existing urban regeneration instruments is carried out, with the intention of studying their impact, emphasizing the concepts of gentrification and the potential expulsion of residents. Using quantitative and qualitative research techniques and triangulation, the aim is to identify the real impacts of urban regeneration in the territory, while capturing the representations of both residents and actors from local entities and the public administration.In short, based on an analysis focused on a series of case studies in the city of Barcelona, the aim is to identify gaps, space for improvement, and innovative alternatives for both the study and the intervention in urban regeneration aimed at vulnerable neighborhoods, ensuring actions that tend to mitigate their adverse effects, the rooting of the resident population, the containment of rents, and sustainable local development. At the same time, the role of the beneficiaries of the programs is emphasized and a greater impact of these and of local organizations in the processes of improvement of their own environments is ensured, achieving greater appropriation and participation in regeneration instruments. Also, the purpose of this work is to achieve a methodology susceptible of being extrapolated to other processes of urban improvement.The results have allowed, broadly speaking, to explain the role of social infrastructure in the generation of social capital, and how both elements are key when thinking about the improvement of vulnerable neighborhoods. Likewise, the need to propose integrated approaches (both in research techniques and in the ways of intervening in the territory), if the intention is to regenerate to integrate and not to expel.
  

DOCTORAL DEGREE IN URBANISM

• LUZURIAGA TORRES, MARÍA FERNANDA: Ecologías [des]tejidas. Un discurso sobre la 'relación'.
  
  Author: LUZURIAGA TORRES, MARÍA FERNANDA
  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: 06/05/2025
  Deposit END date: 19/05/2025
  Thesis director: SOTOCA GARCIA, ADOLFO
  Thesis abstract: This research addresses the theme of coexistence, a concept of increasing relevance in the current context, marked by the economic, social, and environmental crises that have been manifesting globally since the beginning of this century. These crises have challenged the fragmented visions of Western modernity's urban thought, which divide reality into dichotomies such as: nature-culture, center-periphery, subject-object, public-private, or masculinity-femininity, compelling us to adopt new ways of thinking about space and its project. In this context, 'ecology' and 'body' have become key notions for rethinking coexistence among 'differents': human and non-human beings, desires, intentions, economies, ecosystems. The Amazon, being a place where diverse actors, peoples and nationalities, forms of spatial production, territorial conflicts over the extraction of natural resources, and imaginaries about space converge, is a place where the project of coexistence becomes particularly relevant.However, traditionally the Amazon has been represented through Western approaches that, implicitly, reproduce colonial matrix values and homogenizing visions of the region. This research, which focuses on the Tena canton, in the Ecuadorian Amazonian foothills, proposes a dual objective. On the one hand, it seeks to develop a new perspective that recognizes the invisibilized bodies and their multiple forms of relationship with the territory, overcoming reductionist visions. And, on the other hand, this research aims to rethink coexistence in a fragmented space: the Amazon is neither a primeval forest nor a purely rural space, but a dislocated territory where 'differents' coexist: peoples and nationalities, intentions, ways of life that produce a multiplicity of 'ecologies'.To fulfill this dual objective, it has been necessary to develop a specific interpretation methodology, which has been redefined throughout the course of the research. It is not, therefore, the rigid application of a pre-established protocol. While it has been required to collect and analyze both quantitative and qualitative data, as well as reconstruct the state of the art on the Amazon in urban studies. However, from the limitations and problems of insufficiency identified in this first stage, we realized that it was necessary to determine a coherent form of research, consistent with the characters of 'vacillation' and 'instability' of the Amazonian space. Hence, an approach to other disciplinary fields such as anthropology and sociology has been fundamental. This has allowed us to combine tools, resources, discourses, and concepts, paving the way to enter into 'relationship' with these complex realities, from our own bodily experience.Thus, traversing the territories and attentive to the characters constructed in the singularity of their daily lives, it was possible to establish a relationship between two key elements: socio-spatial analysis and the use of decolonial conceptual tools such as Eduardo Viveiros de Castro's 'cannibal thinking' and Silvia Rivera Cusicanqui's 'ch'ixi'. The socio-spatial analysis is carried out through the construction of a series of 'microhistories', analyzing the dynamics of 'power', 'resistance', and 'cannibalization' in the Amazonian space, paying special attention to the relationship between 'body' and 'territory'. The postulated hypothesis is that the dynamics of relationship can be interpreted as a result of the knowledge of bodies, which are patterns of resistance that make coexistence possible. Resistance understood as an active defense of human and non-human life, overcoming Western matrix discourses.