Doctoral School

Reading date: 15/12/2025

• MARTÍ ELÍAS, JOAN MARIA: Hidrografies urbanes. Cicle de l’aigua, forma urbana i estructura territorial al la Vall Baixa i al Delta del Llobregat
  
  Author: MARTÍ ELÍAS, JOAN 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 URBANISM
  Department: Department of Urbanism, Territory and Landscape (DUTP)
  Mode: Normal
  Deposit date: 31/10/2025
  Reading date: 15/12/2025
  Reading time: 17:00
  Reading place: ETSAB (Escuela Técnica Superior de Arquitectura de Barcelona) - Planta Baja - Sala de GradosAv. Diagonal, 649-651 - 08028 - Barcelona
  Thesis director: CROSAS ARMENGOL, CARLES
  Thesis abstract: The research dives in the relationship between urban morphology and water cycle from an ecosystemic perspective that integrates physical, territorial, and infrastructural components. The objective is to demonstrate that urban morphology is directly related with hydrological dynamics and that, therefore, it can become a key tool for redefining water management strategies in metropolitan contexts.This dissertation is grounded in the intensive exploration of a specific territory (la Vall Baixa and the Delta del Llobregat) through five successive approaches, addressing the territory from the metropolitan scale down to local urban fabrics. This process constructs a multi-scalar reading that relates the physical, infrastructural, and morphological conditions of the city to its hydrological dynamics.The territorial approach is enriched by a historical and conceptual dimension that reconstructs a genealogy of urban thought in an ecosystem perspective, based on figures and projects that conceived the city as a living system, dependent on its exchanges with the territory. The research also revisits nineteenth-century projects that, with a hygienist outlook, anticipated “proto-ecological” visions. In this regard, Garcia Fària’s proposal for the sanitation of the Eixample and the diversion of the river Llobregat constitutes a paradigmatic case that anticipates an integrated territorial interpretation, establishing a valuable precedent for contemporary urban planning practice.On this basis, the final stretch of the river Llobregat is studied, revealing the complexity of a hybrid morphology resulting from the superimposition of natural and anthropic logics. The river is presented as an ecological and productive infrastructure, a space where the persistence of hydraulic and agricultural traces coexists with metropolitan urbanization pressures. From here, the research turns to the underground dimension, analyzing the delta aquifer as a key element for environmental balance. Infiltration dynamics, alterations derived from urbanization, and opportunities for the reconversion of industrial and logistical spaces based on hydrogeological criteria are examined. The three-dimensional reading of the territory makes it possible to link surface and subsoil and to propose infiltration and regulation devices that restore natural functions.In the central part of the dissertation, these criteria are applied at an intermediate analytical scale, proposing the sub-basin as a functional unit of analysis and design, due to its capacity to integrate topographical continuities, road structures, and open spaces. On this basis, a parametric methodology is developed, articulated into six actions (capture, consumption, treatment, infiltration, retention, and reuse) applied to multiple metropolitan fabrics. A multi-scalar analysis makes it possible to identify hydromorphological indicators that guide design decisions according to context and urban structure. The result is an operative atlas that proposes ranges of intervention and adaptive criteria for urban transformation guided by hydrological principles.Finally, the research advances a paradigm shift: water becomes a design vector, not merely a technical constraint. Public space, the road network, and urban voids are recognized as multifunctional water devices, while the underground dimension is considered an active and inseparable layer of the urban system. This three-dimensional and complex vision relates metabolism and form, while articulating both regional scale and urban project.Overall, the dissertation contributes to creating a culture of urban design that integrates water as a vector of intelligibility and ordering, where the term “hidrografia” is not understood in the traditional sense of describing river courses, but rather as a critical instrument for mapping the presence, movement, and structuring capacity of water in all its forms.
  

• TRULLENQUE ORTIZ, MARTÍN: A Cross-Layer Perspective on Radio Resource Management and User Quality of Experience in V2X-Enabled 5G Networks.
  
  Author: TRULLENQUE ORTIZ, MARTÍN
  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: 31/10/2025
  Reading date: 15/12/2025
  Reading time: 11:00
  Reading place: Aula de Teleensenyament. Edifici B3, Campus Nord
  Thesis director: SALLENT ROIG, JOSE ORIOL | CAMPS MUR, DANIEL
  Thesis abstract: Vehicular communications are expected to be among the main verticals benefiting from the massive rollout of 5G. The millisecond latencies enabled by 5G, combined with network slicing and the global coverage offered by public cellular networks, leverage the conditions to adopt public cellular networks for vehicle-to-everything (V2X) communications. This vertical will introduce new services that generate additional traffic demands on existing radio infrastructure, posing distinct challenges for mobile network operators. From a service perspective, V2X services require both low latency and high reliability. For example, under a periodic exchange position information between vehicles, a single dropped packet can increase the position error estimate and jeopardize road safety. From a network perspective, vehicular services will demand resources differently from generic Internet users, often creating high user densities along highways, where user density is typically [MT1.1]low and radio deployment is not dense. Moreover, vehicle mobility can lead to long periods during which cells serve very few users, followed by periods of high demand that may compromise resource availability, especially during traffic congestion. To this end, this thesis investigates solutions for cell overloads caused by traffic jams when V2X services run over public cellular networks.The first contribution of this work is an in-depth analysis of vehicular mobility based on a dataset of realistic traces, aimed at understanding how traffic congestion drains radio resources. Studying vehicle flows across cells reveals user concentrations at specific road locations, providing opportunities for congestion control mechanisms. The second contribution examines the repeatability of high-load situations in a real 5G deployment. Measurements over a 5G NSA network show that congestion exhibits consistent daily patterns, duration, and load characteristics, motivating deterministic congestion control strategies.Building on these insights, this thesis proposes and implements two complementary approaches: a network-layer mobility load balancing algorithm that diverts vehicles at cell edges to neighbouring cells during traffic jams, and an application-layer mechanism that manages service degradation to control packet loss under overload. Combining both approaches, this thesis has conceived, designed, implemented and evaluated FOM-5G, a framework capable to derive the best congestion control strategy for each cell overload. The framework leverages the use of historical information data to optimize cell congestion responses through experience. Beyond its design and evaluation, the thesis also proposes an architectural integration of FOM-5G within the O-RAN architecture and network exposure API defined in the 5G core. Finally, the framework is validated through simulations using diverse vehicular traces that capture urban congestion scenarios. Results confirm FOM-5G’s ability to distinguish between different congestion events and select the optimal mitigation strategy, demonstrating its effectiveness in ensuring reliable V2X communications over public cellular networks.
  

Reading date: 16/12/2025

• AL AWAD, ABDULRAHMAN: Multiscale Multiphysics Investigation of Helium Bubble Formation and Dynamics in Liquid Lead-Lithium Eutectic
  
  Author: AL AWAD, ABDULRAHMAN
  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: Department of Physics (FIS)
  Mode: Normal
  Deposit date: 03/11/2025
  Reading date: 16/12/2025
  Reading time: 11:00
  Reading place: Aula C4 (porta 31.07) Secció d'Enginyeria Nuclear, pavelló C, ETSEIB (Campus Sud)
  Thesis director: BATET MIRACLE, LLUIS | SEDANO MIGUEL, LUIS ANGEL
  Thesis abstract: Liquid metals (LMs) and their alloys are characterized with excellent thermophysical and dynamic properties for heat transport purposes, thus rendering them as promising candidates in advanced energy-production technologies such as the nuclear fusion energy. Liquid lead-lithium eutectic (LLE) alloy remains a key medium of the various breeding blanket (BB) concepts of the EU DEMO design. In LLE-BBs, helium (He) is produced in a mole-to-mole ratio with tritium by nuclear reactions, and technical concerns regarding the state of He in liquid LLE alloy have been raised since the 1990s. Gas-bubble nucleation in weak liquid–gas solutions has been a challenging topic in theory, experimentation, and computer simulations, especially given the expected very low solubility of He in LMs and the scarcity of experimental data. Despite the continuous efforts, the He nucleation issue still lacks conclusive findings and robust estimations of relevant parameters, and the main objective of this thesis is to exploit ab initio (AIMD) and classical molecular dynamics (CMD) simulations in order to shed light on the underlying physics and theory, and to estimate the thermodynamic and kinetic conditions required for He bubbles to nucleate and grow in a manner that facilitates the integration of results and findings into macroscopic models, e.g., CFD models, for engineering design and nuclear safety purposes. Additionally, it aims to pave the way and generally contextualize the use of atomistic simulations in the field. In the first part of this thesis, the invaluable AIMD methods using SIESTA code are utilized to support and justify the selection and construction of classical interatomic potentials, where liquid Li, Pb and LLE alloy are systematically investigated. In the second part, a classical potential of the embedded-atom-method class is parametrized for liquid Li using mechanical and non-mechanical properties. A mixing scheme is introduced to reproduce properties of liquid LLE alloy. To minimize the arbitrariness of functional forms, the parametrization schemes address the uniqueness problem. CMD simulations with LAMMPS code are performed to extensively investigate and estimate static and dynamic properties of pure LM and He/LM systems, both bulk and interfacial properties. In the third part, in analogy with recent advances in crystallization and droplet formation studies, the diffusive-shielding stabilization, the thermodynamic irreversibility of bulk nanobubbles (bNBs) mechanisms and the mean-first passage times theory are revisited and deployed to characterize the stability of He-bNBs in liquid LLE alloy, as inspired from bubble stability theories and experiments in closed and finite-volume systems. Namely, an analytical perturbation approach with an appropriate equation-of-state of He-bNBs and a stochastic and kinetic approach via forward CMD simulations are established, and the consistency and equivalency of both is demonstrated and thoroughly discussed. Most importantly, the underlying theoretical bases, assumptions, limitations and their computational counterparts are extensively described and illustrated. The overall proposed framework resolves ambiguities about the influence of the simulation domain and time on the observed bNBs in CMD simulations. Essentially, it provides a novel and plausible explanation for helium-bNBs existence and persistence by carefully assessing and estimating the thermodynamic equilibrium conditions; hence, their stability and longevity are shown not to be in violation of the fundamental laws of solubility and diffusivity, at least in CMD simulations and given the relatively high supersaturation levels. Lastly, thermodynamic and kinetic conditions required for the helium nucleation phenomena to take place at LLE-BBs operating conditions are inferred, based on the various investigated theories and performed computations, and coherently, macroscopic modelling suggestions and recommendations are provided.
  

• BUSTO ABADIA, JAIME: Estudio y mejora del flujo armónico de cargas
  
  Author: BUSTO ABADIA, JAIME
  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: 18/11/2025
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: MESAS GARCIA, JUAN JOSE | SAINZ SAPERA, LUIS
  Thesis abstract: The presence of voltage and current harmonics in electrical installations is a long-standing challenge in the field of power quality, a challenge that remains relevant today due to the continuous increase in nonlinear loads connected to these installations, the growing sensitivity of electrical devices to disturbances, and the need to predict and prevent problems arising from all the above factors. To address this, both standards that evaluate and quantify the tolerable limits of harmonic distortion for the electrical system and the loads connected to it have been developed, as well as various tools based on the formulation and numerical solution of the system of equations posed in harmonic load flow analysis. In addition, procedures to mitigate the harmonic problem have been studied. In this context, the development of the harmonic load flow formulation has always aimed to study the problem using the smallest possible number of equations that still yield correct results, thereby reducing the numerical problems involved in its mathematical solution without sacrificing accuracy. Although this formulation has already been extensively studied, researchers continue to propose improvements to it that allow the aforementioned objectives to be better achieved.Considering all the above, the objectives established in the thesis, which have ultimately been achieved, are:1.- Development and programming of a new harmonic load flow formulation that improves the convergence properties of current formulations.2.- Harmonic sensitivity analysis of the four most common types of nonlinear loads in electrical installations (single-phase and three-phase rectifiers with capacitive filters, three-phase 6-pulse rectifiers, and discharge lamps), and incorporation of the results into the new formulation.3.- Validation of the new formulation against those existing in the literature using a 3-bus academic network and an IEEE 14-bus network expanded to 23 buses.4.- Study of the harmonic cancellation phenomenon using the new formulation and the IEEE 14-bus network expanded to 23 buses.The following methodology was employed to achieve these goals:In the first part of the thesis, the state of the art of existing harmonic load flow formulations found in the literature was analysed, along with the treatment of variables, equations, and the problems they present. Then, the four common types of nonlinear loads in electrical installations were described, along with their modelling and their voltage and current responses to harmonic excitations.Subsequently, the new formulation was presented, including the theoretical foundations it is based on, the calculation stages it is divided into, as well as the data used and the unknowns to be calculated. The harmonic sensitivity analysis of nonlinear loads was also shown, which determines the differentiated treatment each will receive in the new formulation.Next, two application examples were presented to validate the results obtained. The new formulation was applied to two networks of different complexity, analysing the results and comparing them with those obtained using other existing formulations, both with single and aggregated loads.The final part addressed the study of harmonic cancellation in several groups of aggregated nonlinear loads, calculating the harmonic cancellation rate in each case using the new formulation developed.
  

• MIRZAY SHAHIM, MAAHIN: Catalytic Properties of Amorphous Alloys
  
  Author: MIRZAY SHAHIM, MAAHIN
  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: 17/11/2025
  Reading date: 16/12/2025
  Reading time: 15:00
  Reading place: Sala Polivalent, Edifici I planta 0, espai I.0.1, EEBE Campus Besós
  Thesis director: PINEDA SOLER, ELOY | SOLER TURU, LLUIS
  Thesis abstract: This thesis explores the catalytic potential of metallic glasses (MGs) and their combination with cerium oxide (CeO₂) for low-temperature carbon monoxide (CO) oxidation and CO preferential oxidation (COPrOx) reactions. Metallic glasses, due to their non-crystalline structure and tunable composition, offer a promising platform for catalytic applications when appropriately engineered. The study focuses on three primary MG systems: Ce65Al35, Pd77Si16.5Cu6.5, and Cu48Zr48Al4, examining their structural characteristics, and catalytic behavior. The results showed that the Ce65Al35 metallic glass has limited catalytic activity, even after various activation treatments such as ball milling, calcination, or combination with CeO2. However, doping the binary Ce-Al system with Pd (Ce61Al35Pd4) markedly improved performance, achieving 100% CO conversion at 300°C when ball milled. Interestingly, mixing this ternary MG with CeO₂ did not provide further enhancement, indicating that Pd’s role is dominant and not synergistic with ceria. The Pd77Si16.5Cu6.5 MG emerged as the most effective standalone catalyst, delivering full CO conversion at only 240°C. Which could be attributed to Pd and its optimized distribution in the amorphous matrix. Control experiments with binary alloys (Pd77Si23 and Cu6Si94) highlighted the importance of both composition and structural processing, particularly the necessity of melt spinning and ball milling to generate active, fine-particle structures.Another major contribution of this work is the development and detailed characterization of Cu-based MG/CeO2 composites, especially Cu48Zr48Al4.These systems showed strong activity and stability in both CO and COPrOx reactions, with performance enhanced through ball milling. Structural and operando analyses (XPS, EXAFS, NEXAFS, and XRD) confirmed that the catalysts undergo surface rearrangement during reaction, stabilizing catalytically active Cu(I) atoms. A spontaneous aging phenomenon and a similar change under hydrogen pre-reduction pointed to the dynamic evolution of active sites during real operation conditions. This study demonstrates that mechanochemical synthesis and careful structural design of MG/CeO₂ composites enable the development of efficient, low-cost, and stable oxidation catalysts. These findings offer new strategies for creating highly active materials for pollution control and hydrogen purification technologies, opening the path to use amorphous metals for heterogeneous catalysis.