Theses authorised for defence

DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY

• GASPARINO FERREIRA DA SILVA, LUCAS: High-performance low-dissipation algorithms for simulation of turbulent compressible flows
  
  Author: GASPARINO FERREIRA DA SILVA, LUCAS
  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 AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Deposit date: 03/04/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: LEHMKUHL BARBA, ORIOL | MIRA MARTÍNEZ, DANIEL
  Committee:
       PRESIDENT: RUBIO CALZADO, GONZALO
       SECRETARI: JOFRE CRUANYES, LLUÍS
       VOCAL: COLOMBO, ALESSANDRO
  Thesis abstract: Motivated by recent advances in computational technology aiming at exascale capabilities, which implies a need for applicationscapable of taking advantage of these new supercomputing architectures, this work will present two algorithms aimed at implementing an efficient and low-dissipation algorithm focused on LESand DNS of turbulent compressible flows.The basis for the algorithms is the Continuous Galerkin method applied to elements whose nodes and quadrature points areformed from the Gauss-Lobatto-Legendre roots, resulting in a SpectralElements Method. Throughout this work, it will be evidenced that this formulation leads to highly efficient kernels for discretizingthe convective and diffusive terms of the compressible Navier-Stokes equations, with the added benefit that the order of the scheme is coupled with the order of the shape functionpolynomials employed by the elements themselves, significantly simplifying the process of increasing the order of the scheme.To achieve a stable Total Variational Diminishing algorithm, the \acrshort{sem} scheme will be paired with an EntropyViscosity-based stabilization model and a suitable splitting of the nonlinear convective terms will be employed to eliminate aliasing issues that occur in the \acrshort{sem} formulation.This spatial discretization is then coupled with both an explicit and a semi-implicit scheme to account for the temporal nature ofthe flow equations. The explicit version of the algorithm is expected to be simple and efficient per time step, but due to its \acrshort{cfl} condition limitation, the semi-implicit version is alsoproposed to allow for better overall performance incases where the time-step becomes overly limited, such as in wall-bounded flows.Considering the focus on producing a \acrshort{cfd} application towards the exascale future, an important aspect of this work isthat both algorithms are proposed with a full \acrshort{gpu}implementation in mind: the use of accelerators is expected to be a key aspect of future supercomputing architectures, and thus itis important to design these algorithms with this in mind.Examples detailing the performance of both algorithms will be presented both in the case of a single device and when distributedarchitectures using multiple devices are employed.
  
• RADHAKRISHNAN, SARATH: NON-EQUILIBRIUM WALL MODELING IN LES OF HIGH-SPEED TRANSITIONAL FLOWS
  
  Author: RADHAKRISHNAN, SARATH
  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 AEROSPACE SCIENCE AND TECHNOLOGY
  Department: Department of Physics (FIS)
  Mode: Normal
  Deposit date: 05/04/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: LEHMKUHL BARBA, ORIOL | MIRA MARTÍNEZ, DANIEL
  Committee:
       PRESIDENT: VINUESA MOLTIVA, RICARDO
       SECRETARI: RODRIGUEZ PEREZ, IVETTE MARIA
       VOCAL: ALCÁNTARA ÁVILA, FRANCISCO
  Thesis abstract: Wall-modeled large eddy simulation (WMLES) is a practical tool to perform the wall-bounded large eddy simulation (LES) with less computational cost by avoiding explicit resolution of the region near the wall. However, its use is limited in flows that have high non-equilibrium effects, like separation and/or transition. In this work, three wall modeling strategies are presented, two of them based on high-fidelity data. First, a technique is presented to improve the robustness of the state-of-the-art algebraic wall shear stress model. Second, an equilibrium-data-driven wall shear stress model is developed using the LES of the channel data. The key purpose of this is to estabilish the methodology of model development using high-fidelity data. The model is built using a machine learning technique that uses gradient-boosted regression trees (GBRT). The objective of the model is to learn the boundary layer of a turbulent channel flow so that it can be used in significantly different flows where the equilibrium assumptions are valid. The importance of selecting the appropriate data for training and the importance of choosing the input of the model are described. The model is validated a priori and a posteriori. A posteriori tests are conducted by implementing the model in a multiphysics solver and using it in the turbulent channel flow and in the flow over a wall-mounted hump. The performance of the model is compared with an algebraic wall shear stress model to understand the strengths and shortcomings of the data-based models and further improve the same. In the next step, the model is upgraded to a non-equilibrium wall model by using non-equilibrium data for the training. The high-fidelity data chosen for training include the Direct Numerical Simulation (DNS) of a double diffuser that has strong non-equilibrium flow regions and LES of a channel flow. The ultimate purpose of this model is to distinguish between equilibrium and non-equilibrium regions and to provide the appropriate wall shear stress. The ML system used for this study is also GBRT. The model is tested a priori and a posteriori. A posteriori tests are conducted on the diffuser, channel flows, flow over the hump, and junction flows. These tests showed that the model is very effective for corner flows and flows that involve relaminarization, while it performs rather less effectively in recirculation regions.
  

DOCTORAL DEGREE IN ARCHITECTURAL, BUILDING CONSTRUCTION AND URBANISM TECHNOLOGY

• RAKHSH MAHPOUR, ALI: Suitability of new lime nonwoven layered flax fiber composite as a reinforcement masonry historical structures system: Microstructural, mechanical, durability and sustainability assessment
  
  Author: RAKHSH MAHPOUR, ALI
  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, BUILDING CONSTRUCTION AND URBANISM TECHNOLOGY
  Department: Department of Architectural Technology (TA)
  Mode: Article-based thesis
  Deposit date: 27/03/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: CLARAMUNT BLANES, JOSE | ROSELL AMIGÓ, JUAN RAMON
  Committee:
       PRESIDENT: DE ANDRADE SILVA, FLAVIO
       SECRETARI: CORNADÓ BARDÓN, CÒSSIMA
       VOCAL: SANZ ARAUZ, DAVID
  Thesis abstract: This thesis investigates the feasibility and potential applications of flax fiber-reinforced lime mortars in masonry construction, particularly focusing on the seismic retrofitting of Unreinforced Masonry (URM) buildings. The composite material, featuring a non-woven structure of flax fiber layers within the lime mortar matrix, undergoes a comprehensive examination with a specific emphasis on mechanical properties, durability, and consistency. Structured as a collection of articles, the thesis covers various dimensions to provide a holistic understanding of the material's capabilities and applications. The first article delves into the mechanical characterization of Flax Fiber Reinforced Lime Mortars. This involves a rigorous assessment of properties such as tensile strength, compressive strength, flexural strength, and toughness. These mechanical attributes are crucial for determining the material's structural integrity and its potential effectiveness in retrofitting applications.In addition to mechanical properties, the thesis explores the durability of flax fiber-reinforced lime mortars. Durability tests are designed to simulate long-term exposure to environmental conditions, including moisture, temperature changes, and other potential stressors. Evaluating the material's resistance to these factors is essential for ensuring its performance and longevity in real-world applications. An integral part of the research involves investigating the optimal configuration of flax fiber layers within the lime mortar. This aspect aims to optimize the composite's flexibility, crack resistance, and chemical compatibility with historic masonry materials. The layered composition is a critical consideration for achieving the desired structural enhancements while maintaining the material's compatibility with historical structures. Furthermore, the thesis contributes to the understanding of the adhesion between flax fiber-reinforced lime mortars and masonry materials. The adhesion characteristics play a pivotal role in determining the effectiveness of the material as a retrofitting solution for URM buildings. The study aims to provide valuable insights into the mechanical properties, durability, and adhesion to ensure a comprehensive understanding of the material's suitability for historical masonry structures.In conclusion, this research, encapsulated in a series of articles, offers a thorough exploration of flax fiber-reinforced lime mortars for masonry construction. The emphasis on mechanical properties, durability, and adhesion positions the material as a potential innovative solution for retrofitting URM buildings. This not only aligns with sustainability goals but also ensures the preservation of cultural heritage. Looking forward, the thesis provides a foundation for further research, suggesting avenues such as numerical modeling and additive manufacturing for a more nuanced understanding and practical application of the developed materials in the construction industry.
  

DOCTORAL DEGREE IN ARCHITECTURAL, CIVIL AND URBAN HERITAGE AND REFURBISHMENT OF EXISTING BUILDINGS

• ZHANG, ZHIHUI: Linking architecture and emotions: sensory dynamics and methodological innovations
  
  Author: ZHANG, ZHIHUI
  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: (RA)
  Mode: Article-based thesis
  Deposit date: 25/03/2024
  Reading date: 07/05/2024
  Reading time: 11:30
  Reading place: Sala de Graus ETSAB. Planta Baixa (E.T.S. Arquitectura de Barcelona)
  Thesis director: FORT MIR, JOSEP MARIA | GIMÉNEZ MATEU, LUIS
  Committee:
       PRESIDENT: FONSECA ESCUDERO, DAVID
       SECRETARI: NAVARRO DELGADO, ISIDRO
       VOCAL: VENTURA RODÀ, ORIOL
  Thesis abstract: This study delves deeply into the complex relationship between the field of architecture and human emotions, aiming to fill a significant gap in existing research. It extensively explores the profound impact of architectural design elements, such as lighting, colour schemes, and the integration of natural landscapes, on emotional responses. This research goes beyond traditional focuses on aesthetics and sustainability, striving to innovate methods for assessing the emotional impact of architectural spaces.In this study, we adopted a technological pathway from the laboratory to virtual reality, and finally to AI, combining theoretical analysis with practical experiments and case studies. The main research includes examining the effects of lighting and spatial dimension variations on people's emotions, as well as the application of facial emotion recognition technology in virtual reality architectural environments, exploring AI's perceptual capabilities as a tool in architectural design. These studies aim to narrow the gap between theoretical research and practical application, providing new perspectives and empirical data for the field of architectural design.The study concludes with a reflection on the methodologies used and their broader implications for architectural design practice. It offers specific strategies for architects and designers, aimed at creating spaces that resonate emotionally and add substantial value to human experiences. By prioritizing emotional factors in the design process, this research seeks to enhance overall quality of life and promote well-being in thoughtfully designed architectural spaces.
  

DOCTORAL DEGREE IN AUTOMATIC CONTROL, ROBOTICS AND VISION

• MARTÍ SAUMELL, JOSEP: Agile aerial manipulation: an approach based on full-body dynamics and model predictive control
  
  Author: MARTÍ SAUMELL, 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 AUTOMATIC CONTROL, ROBOTICS AND VISION
  Department: Institute of Robotics and Industrial Informatics (IRI)
  Mode: Normal
  Deposit date: 26/03/2024
  Reading date: 30/04/2024
  Reading time: 11:00
  Reading place: Sala de Juntes de la Facultat Matemàtiques i Estadística (FME) de la UPC, C/Pau Gargallo, 14, 08028 Barcelona
  Thesis director: SANTAMARIA NAVARRO, ANGEL | SOLÀ ORTEGA, JOAN
  Committee:
       PRESIDENT: MANSARD, NICOLAS
       SECRETARI: MORCEGO SEIX, BERNARDO
       VOCAL: LIPPIELLO, VINCENZO
  Thesis abstract: Aerial manipulators, which commonly take the form of multirotors with attached robotic limbs, primarily employ their limbs for pure manipulation tasks and do not rely on them during aerial locomotion. Besides, their movement tends to be slow. This thesis aims to enhance an aerial manipulator¿s agility by harnessing its limb¿s capabilities to augment its overall motion. This objective involves investigating various modes of utilizing the limb: as a tail for aerial locomotion, as an arm for aerial manipulation, or as a leg for hybrid aerial-contact locomotion. The present thesis contributes to two specific domains: 1. Generation and control of agile motions for aerial manipulators, 2. Design and construction of a specialized aerial manipulator for executing agile motions.Generating agile motions requires predicting the movement of the robot considering its dynamics so that these dynamics can be used to favor the robot¿s motion. Hence, we can achieve complex maneuvers with relative ease. Optimal control is a trajectory-generation technique that meets these requirements, and that is central to this thesis. We encode the robot¿s tasks as cost functions of the optimal control problem (OCP) and use the whole-body dynamics as the constraints of the dynamic system. On the control side, to deploy such trajectories in a real robot, we use model predictive control (MPC) techniques, which is the closed-loop control extension of optimal control. To get the control command, an MPC controller solves the OCP in which we have encoded the agile trajectory, and then the controller applies the first command of the solution control trajectory. Thus, MPC requires solving an OCP at the control rate, i.e., within a few milliseconds. This forces us to use fast, specialized solvers based on the dynamic programming principle, such as differential dynamic programming (DDP). In their original form, these solvers cannot consider the control bounds. These bounds are important to create trajectories compatible with the real robot. To tackle this problem, in this thesis, we propose two DDP-based methods to consider the control bounds: one is based on a squashing function, and the other is based on a projection method. Even with these solvers, we face challenges in meeting the solving rate and are forced to reduce the MPC horizon. Reducing the MPC horizon implies that the MPC can only see a portion of the original OCP, possibly leaving out some of the tasks. This affects the predictive capability of the controller and compromises the accomplishment of the tasks, especially those that require an elaborate and dynamic maneuver. To overcome this difficulty, in this thesis, we propose to update, at each MPC iteration, the terminal cost function in the MPC with a function that encodes the part of the trajectory that remains unseen by the controller.Regarding robot design, deploying agile motions becomes difficult with existing aerial manipulators, which are generally big-size multirotor platforms with non-compliant, high-gear ratio limbs. In this thesis, we present Borinot, an open-source aerial robotic platform designed to research hybrid agile locomotion and manipulation using flight and contacts. This platform features an agile and powerful hexarotor that can be outfitted with torque-actuated limbs of diverse architecture, allowing for whole-body dynamic control. We present experiments with this robot showcasing different agile motions.In addition to the stated contributions, this thesis contributes in other areas required to operate the robot, such as a procedure for identifying the dynamical parameters based on factor-graph estimation or a hardware enhancement that allows for direct thrust control of Borinot¿s rotors.
  
• ORTI NAVARRO, JOAN: The Surface Defect Identification Problem in The Industry: A Novel Approach with Semantic Segmentation and Generative Adversarial Networks
  
  Author: ORTI NAVARRO, JOAN
  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: 18/03/2024
  Reading date: 10/05/2024
  Reading time: 11:00
  Reading place: Sala Actes de la Facultat de Matemàtiques i Estadística (FME), Campus Diagonal Sud, Carrer de Pau Gargallo, 14, 08028 Barcelona
  Thesis director: MORENO NOGUER, FRANCESC D'ASSIS | PUIG CAYUELA, VICENÇ
  Committee:
       PRESIDENT: SERRATOSA CASANELLES, FRANCESC ASSIS
       SECRETARI: GRAU SALDES, ANTONI
       VOCAL: VENTURA ROYO, CARLES
  Thesis abstract: Surface inspection of coated surfaces in the automotive industry, traditionally has been a manual process in charge of keen eye operators in charge of inspecting the whole car body. However, as might be deducted, manual inspections often lack repetitiveness and reliability, very much desired in a such a strict sector. Computer vision tackled this problem with the first automated defect detection systems, pinpointing the defects in the car body and their size. Nevertheless, as these systems are constrained to just detection, the operator is still in charge of properly labelling the defects to rework them correctly. Additionally, there is a lack of traceability between the process and the defects themselves, taking longer to identify the root causes of faulty paint shop facilities.In this thesis, we address the multidisciplinary problem of defect identification in specular surfaces, with two main research lines. In the first one, we developed a novel illumination approach based on indirect diffuse lighting, in contrast with the conventional specular reflection. Together with a high resolution camera, we demonstrated an important improvement in terms of defect recognition with respect to the existing defect detection systems. These results are assessed with specialized auditors from the SEAT Martorell factory.The second research line, oriented to computer vision, explore the possibilities of implementing a deep learning solution for industrial defect identification. We developed a fast and reliable context aggregation model, featuring dilated convolutions and residual connections between opposite layers. This model is then trained following a loss leverage between classification and segmentation, for a smoother training procedure. Additionally, in order to cope the frequent class imbalances in the industrial datasets, we developed a guided-crop image augmentation strategy, based on cropping real defect randomly into non-defective images to generate synthetic new samples. The results state that the combination of this model with this augmentation strategy is able to outperform well-known segmentation models.Eventually, for data scarcity situations, we resorted to image synthesis methods to generate new fake samples. Models like Pix2pix have proven to be able to generate close to real im- ages, helping the segmentation model to converge faster than with the previous guided-crop image augmentation technique. Later, this generative method will be surpassed by a more sophisticated one, which features spatially-adaptive normalization layers that help to synthe- size images even without an encoder. Overall, it demonstrated good capabilities in multiple industrial datasets.
  

DOCTORAL DEGREE IN BIOMEDICAL ENGINEERING

• FERNÁNDEZ BOSMAN, DAVID: PyMCGPU-IR: a new tool for patient dose monitoring in interventional radiology procedures
  
  Author: FERNÁNDEZ BOSMAN, DAVID
  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: Institute of Energy Technologies (INTE)
  Mode: Normal
  Deposit date: 27/02/2024
  Reading date: 24/04/2024
  Reading time: 11:30
  Reading place: Aula Capella, Escola Tècnica Superior d'Enginyeria Industrial de Barcelona (ETSEIB), Av. Diagonal, 647. 08028 Barcelona
  Thesis director: GINJAUME EGIDO, MERCE | DUCH GUILLEN, MARIA AMOR
  Committee:
       PRESIDENT: SANS MERCE, MARTA
       SECRETARI: SEMPAU ROMA, JOSEP
       VOCAL: SÁNCHEZ CASANUEVA, ROBERTO MARIANO
  Thesis abstract: Interventional radiology procedures are associated with potentially high radiation doses to the skin. The 2013/59/EURATOM Directive establishes that the equipment used for interventional radiology must have a device or a feature informing the practitioner of relevant parameters for assessing patient dose at the end of the procedure. Monte Carlo codes of radiation transport are considered to be one of the most reliable tools available to assess doses. However, they are usually too time consuming for use in clinical practice. This thesis has been developed at the Institute of Energy Technologies of the Universitat Politècnica de Catalunya within the framework of the European project "Implications of Medical Low Dose Radiation Exposure" (MEDIRAD). The main objective of this work is to develop a software tool based on the Monte Carlo program MC-GPU for assessing the skin dose in patients undergoing interventional radiology (IR) procedures. The achievement of this objective can be divided into two main blocks: the validation of MC-GPU and the development and validation of PyMCGPUIR, a skin dose calculation tool for IR procedures based on MC-GPU. For the validation of MC-GPU, simulations were conducted and compared with the well-validated code PENELOPE/penEasy and then compared against thermoluminescent measurements performed on slab phantoms, both in a calibration laboratory and at a hospital. MC-GPU demonstrated excellent agreement in organ dose distribution, with differences below 1%, despite reducing the calculation time by a factor of 2500. Comparisons with thermoluminescent measurements indicated agreements within 10%, validating MC-GPU¿s ability to provide accurate dose estimates in real clinical setups in very short times. In this work we have also developed PyMCGPU-IR, a new software tool based on the Monte Carlo program MC-GPU for assessing skin dose and organ doses in patients undergoing an interventional radiology (IR) procedure. PyMCGPU-IR has been validated through skin and organ dose measurements in an anthropomorphicphantom and showed differences below 6% in skin dose measurements and mostly below 20% in organ doses in clinical procedures. PyMCGPU-IR offers both, high performance and accuracy for dose assessment when compared with skin and organ dose measurements. It also allows the calculation of dose values at specific positions and organs, the dose distribution and the location of the maximum dose per organ. In addition, PyMCGPU-IR overcomes the time limitations of CPU-based MC codes.In this thesis we have shown that PyMCGPU-IR is an innovative Skin Dose Calculation (SDC) tool that offers higher performance and accuracy for skin dose calculations compared to most available SDCs. Currently, PyMCGPU-IR provides dose values only after the procedure has finished. In the future, PyMCGPU-IR could be adapted to provide real-time dose calculation if real-time radiation source information is available.
  

DOCTORAL DEGREE IN BUSINESS ADMINISTRATION AND MANAGEMENT

• HINOJOSA I RECASENS, JOSEP DOMINGO: Investigación sobre la persistencia, el cambio y la materialidad de la identidad organizacional: entrevistas a expertos y el caso de una empresa centenaria
  
  Author: HINOJOSA I RECASENS, JOSEP DOMINGO
  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: 05/03/2024
  Reading date: 30/05/2024
  Reading time: 11:30
  Reading place: Lectura públicaa l' Aula 28.8 de l'Escola Tècnica Superior d'Enginyeria Industrial de Barcelona (ETSEIB)- UPC
  Thesis director: SUNYER TORRENTS, ALBERT
  Committee:
       PRESIDENT: GARCÍA ÁLVAREZ, MARIA ERCILIA
       SECRETARI: PONS PEREGORT, OLGA
       VOCAL: SELVA OLID, CLARA
  Thesis abstract: ContextThis thesis investigates organizational identity, its persistence and change, and the relationship between identity and material objects. Organizational identity is what the members of an organization answer when they ask themselves: Who are we? and what do we do as an organization?. As a field of research, organizational identity has been gaining relevance in recent decades, especially since the authors Albert and Whetten (1985) established the academic foundations to characterize this concept through the attributes that identity must have: centrality, endurance and differentiation. This characterization was generally accepted by the scientific community and was not questioned for years; it is still considered relevant today. Organizational identity is a broad and complex topic that has been explored by various researchers using qualitative methods. Identity can evolve as organizational practices and narratives are reinterpreted. Some authors consider that identity is dynamic and that it can change as the organization evolves. In this thesis we develop an exploratory research on organizational identity, paying special attention to how identity can adapt, change and be instantiated by material objects. Specifically, this thesis has been structured based on two lines of research: The first line of research studies the persistence of organizational identity and its changes over time, the second line explores the possible relationships between the organizational identity and material artifacts.JustificationThere remains an interesting path to follow in research on organizational identity. Currently, organizational identity is part of the strategic debates and communication plans of many organizations, highlighting the relevance of this concept that can be considered the DNA of an organization. The purpose of this research is to deepen the understanding of organizational identity by exploring how it evolves when the environment changes, when new strategies or different events occur in which identity may face internal or external tensions. Finally, a single in-depth case study is developed exploring the relationships between the identity of an organization and some of its material artifacts.ContributionsThis study has shown that physical objects are part of an identity system that, including other intangible elements, such as verbal communication and narratives, support, instantiate and communicate organizational identity over time. This research results extend the literature on identity, and on the influence and use of material identity objects. The in-depth case study has shown that physical objects has been used to support, instantiate and communicate organizational identity. The data induction process has characterized three different categories of physical objects that provide identity meanings: primal artifacts, identity markers and artifacts created ad hoc.LimitationsThis work provides an exciting opportunity for future research to extend these findings by examining the persistence, change, and materiality of identity in other organizational contexts and industries.
  

DOCTORAL DEGREE IN CHEMICAL PROCESS ENGINEERING

• NASR ESFAHANI, KOUROSH: Mathematical modeling of advanced oxidation processes for the efficient wastewater treatment: Integrated Management of advanced oxidation processes and conventional Bio-Processes for the removal of recalcitrant components
  
  Author: NASR ESFAHANI, KOUROSH
  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: 28/03/2024
  Reading date: 02/07/2024
  Reading time: 11:00
  Reading place: Sala Polivalent de l'Edifici I, Planta baixa, Campus Diagonal-Besòs
  Thesis director: PEREZ MOYA, MONTSERRAT | GRAELLS SOBRE, MOISES
  Committee:
       PRESIDENT: PAIS VILAR, VÍTOR JORGE
       SECRETARI: SOLER TURU, LLUIS
       VOCAL: GARCIA MONTAÑO, JULIA
  Thesis abstract: The objective of this thesis is to contribute to the development of mathematical modeling of Advanced Oxidation Processes (AOPs) aimed at the competent treatment of recalcitrant organic compounds in wastewater. In particular, the Ph.D. thesis first focuses on developing mathematical models of AOPs, implementing these models in software tools, and enabling a deeper understanding of the complex nature of these processes through the detailed simulation of the evolution of chemical species along the reaction time for diverse and unexplored scenarios. Hence, these tools are next used for fitting the models to the experimental data obtained in the laboratory in the course of the thesis or reported in the literature. The fitted models are analyzed and refined through sensitivity analysis techniques, and finally, they are validated and their accuracy assessed. Models are mainly used for addressing operational issues, but also design aspects are considered in regard of the simulation of integrated processes using AOPs and conventional biotreatment processes.The thesis specifically addresses the development of a model for AOPs, above all photo-Fenton processes, including flexible H2O2 supply given as a function of time. The model contributes a practical tool aimed at providing model-based simulation for solving the problem of the management of the H2O2 dosage profile of the photo-Fenton process.The thesis also addresses the problem of the pH dependency of the photo-Fenton by modeling the possibility of performing the photo-Fenton process at near-neutral pH. This is studied by considering the use of iron complexing agents such as ethylenediamine disuccinic acid (EDDS). In a subsequent stage, as a step forward in improving photo-Fenton processes, a reported kinetic model of the Fe(3+)-EDDS mediated photo-Fenton process is extended to include the reactions occurring in the absence of H2O2, when EDDS(¿ 3- )radical generated from the lysis of the Fe(3+)-EDDS complex is responsible for the organic matter degradation. This is achieved by adopting a novel semi-empirical approach based on lumping radical species.Ozonation of wastewater is also studied as a different case of AOPs, focusing in the modeling of ozone decay during the treatment of secondary effluents containing organic matter. This is addressed by proposing a new model, based again in the used of lumped or surrogate concentrations. The ozone model developed is shown to be capable of describing the complex profile of the ozone at different initial concentrations, and has proved accurate to describe the experimental data obtained in the lab, as well as data reported in the literature.The modeling approach adopted in this thesis has also been used to explore integrated processes combining AOPs with other processes, namely conventional biotreatment processes which main acknowledged limitation is the incapacity to remove recalcitrant compounds from wastewaters. The study combined the AOP models developed with standard models such as ASM1 to map the correspondence between the variables employed in each model, and produce the simulation of different scenarios combining these two technologies.As a final remark, the thesis has also addressed the design and development of chemical reactors, particularly prototypes for photo-Fenton processes using 3D-printing. This last study addresses the selection of materials according to different criteria for reactor prototyping and subsequent testing of the chemical suitability of the reactor for carrying out AOPs.
  

DOCTORAL DEGREE IN CIVIL ENGINEERING

• NÚÑEZ CORBACHO, MARC: Aerodynamic shape optimization under uncertainties using embedded methods and adjoint techniques
  
  Author: NÚÑEZ CORBACHO, MARC
  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: 09/04/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: ROSSI BERNECOLI, RICCARDO | BAIGES AZNAR, JOAN
  Committee:
       PRESIDENT: LEHMKUHL BARBA, ORIOL
       SECRETARI: MARTINEZ FRUTOS, JESUS
       VOCAL: RICCHIUTO, MARIO
  Thesis abstract: This thesis develops a framework to perform shape optimization under uncertainties for a body under the action of aerodynamic forces. The solution of the flow is performed with finite elements using the full potential equation with an embedded approach, where the object of study is defined implicitly with a level set function. The optimization problem is solved by combining different software packages to perform the solution of the flow, advance in the optimization loop and perform uncertainty quantification. The first contribution of the thesis is the development of a full embedded approach for the solution of the full potential equation. Due to the inviscid hypothesis of potential solvers, these require the definition of a gap in the computational mesh in order to generate lift, known as the wake. Based on previous works where the wake is defined implicitly with an embedded approach, this work also considers the geometry as an embedded body. Mesh refinement and numerical terms are employed to improve the definition of the geometry in the mesh and ensure the definition of the Kutta condition. The solver is validated for two and three dimensions for subsonic and transonic flows with different reference data. Another contribution of the thesis is the development of the adjoint analysis for the subsonic full potential equation with embedded geometries in two dimensions. Each coordinate of the object of study is considered a design parameter in the adjoint analysis, where the effect of the level set function is considered. The sensitivities of the objective function with respect to the design parameters are validated by comparing them to the sensitivities obtained by using a finite differences approach. A shape optimization problem where the lift coefficient is maximized with geometrical constraints is solved as an example of application of the adjoint sensitivities. The embedded shape optimization problem is extended to consider uncertainties in the inlet condition. The optimization problem is reformulated by choosing a risk measure, the Conditional Value-at-risk, which is minimized. The adjoint sensitivities are adapted for the stochastic case, considering the selected risk measure. The estimation of the risk measure is performed thanks to an external uncertainty quantification library, by applying a novel approach which uses Monte Carlo methods to estimate the Conditional Value-at-risk. The stochastic case is solved in a distributed environment, where each optimization step deploys a Monte Carlo hierarchy to estimate the objective function and its gradients.
  

DOCTORAL DEGREE IN COMPUTER ARCHITECTURE

• NESTOROV, ANNA MARIA: Optimizing serverless architectures for data-intensive analytics workloads
  
  Author: NESTOROV, ANNA 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 COMPUTER ARCHITECTURE
  Department: (DAC)
  Mode: Normal
  Deposit date: 25/03/2024
  Reading date: 03/05/2024
  Reading time: 10:00
  Reading place: Sala C6-E101 - Facultat d'Informàtica de Barcelona (FIB)
  Thesis director: CARRERA PÉREZ, DAVID | BERRAL GARCÍA, JOSEP LLUÍS
  Committee:
       PRESIDENT: SANCHEZ ARTIGAS, MARC
       SECRETARI: GUITART FERNANDEZ, JORDI
       VOCAL: TAHERKORDI, AMIRHOSEIN
  Thesis abstract: Recently, serverless computing has garnered attention from academia and industry due to its on-demand resource provisioning, allowing users to focus solely on their core business logic by breaking down tasks into small stateless functions.Serverless offers benefits like a 'pay-per-use' cost model, greater flexibility, and transparent elastic resource auto-scaling.Researchers in academia and industry are increasingly exploring serverless computing's potential in complex, data-intensive analytics. These tasks, resource-heavy and highly parallel, involve significant inter-function communications. However, this shift presents challenges, requiring alignment with the specific needs and constraints of such applications. This research area is currently considered one of the most compelling areas of study. This thesis shows that it is possible to efficiently execute modern data-intensive analytics workloads, traditionally deployed in managed cloud clusters, within serverless computing environments using direct data inter-function communication and optimized performance-cost efficient resource allocation policies. To demonstrate this thesis, we first build a performance model for serverless workloads, considering data sharing, volume, and communication technologies. The model, with a relative error of 5.52%, evaluates the performance of a representative workload in serverless, analyzing task granularity and concurrency, data locality, resource allocation, and scheduling policies. Our results indicate that the performance of data-intensive analytics workloads in serverless can be up to 4.32x faster depending on how these are deployed. Furthermore, this characterization highlights inefficiencies in centralized object storage and stresses the primary importance of efficient resource use.We then introduce Floki, a data forwarding system that tackles the centralized object storage bottleneck. It enables direct communication between producer-consumer function pairs using fixed-size communication methods. Floki establishes point-to-point data channels for intra- and inter-node data transmission, allowing transparent data transfer and reducing network data copying. This workflow-oriented approach boosts performance and minimize resource requirements without restricting function placement.Our experimental evaluation, performed on the principal communication patterns in distributed systems, shows that Floki reduces the end-to-end time up to 74.95x, decreasing the most extensive data sharing time from 12.55 to 4.33 minutes, saving almost two-thirds of time. Additionally, Floki achieves up to 50,738x of resource-saving, equivalent to a memory allocation of approximately 1.9MB instead of an object storage allocation of 96GB.Finally, we investigates how to achieve efficient resource utilization in modern serverless environments and proposes Dexter, a novel resource allocation manager, leveraging serverless computing elasticity. Dexter continuously monitors application execution, dynamically allocating resources at a fine-grained level combining predictive and reactive strategies to ensure performance-cost efficiency (optimizing total runtime cost). Unlike black-box Machine Learning (ML) models, Dexter reaches a sufficiently good solution, prioritizing simplicity, generality, and ease of understanding. The proposed experimental evaluation demonstrates that our solution achieves a significant cost reduction of up to 4.65x, while improving resource efficiency up to 3.50x, when compared with the default serverless Spark resource allocation that dynamically requests exponentially more executors to accommodate pending tasks. Dexter also enables substantial resource savings, demanding up to 5.71x fewer resources. Dexter is a robust solution to new, unseen workloads, achieving up to 2.72x higher performance-cost efficiency thanks to its conservative resource scaling approach.
  

DOCTORAL DEGREE IN COMPUTING

• ALONSO ALONSO, JESUS: Dynamic Terrain Modeling
  
  Author: ALONSO ALONSO, JESUS
  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 COMPUTING
  Department: Department of Computer Science (CS)
  Mode: Normal
  Deposit date: 18/03/2024
  Reading date: 08/05/2024
  Reading time: 12:00
  Reading place: Sala de Teleensenyament del 'ETSETB, edifici B3, Barcelona Diagonal NORD
  Thesis director: JOAN ARINYO, ROBERT
  Committee:
       PRESIDENT: CHOVER, MIGUEL
       SECRETARI: ARGUDO MEDRANO, OSCAR
       VOCAL: BOSCH GELI, CARLES
  Thesis abstract: This work explores terrain modelling techniques that provide a comprehensive experience in terms of graphical representation, physics interaction and dynamic updates in real-time. In particular, our focus revolves around the creation of a system able to: 1) capture any possible feature we find on terrains, 2) maintain an accurate level of detail, 3) offer rendering and navigation in real-time, 4) include the option of performing dynamic updates in real-time, and 5) support physical interactions of entities also in real-time.Once previous models from the literature are reviewed, two models are proposed that take a digital elevation model as the base structure. The former follows a strategy in which we mimic the geotectonic events we find in nature. The latter uses a sculpting approach with convex polyhedra as a carving tool. To this end, several works are presented.While the first option introduces some gains with limits, the second option is a proposal that accomplishes the five required constraints. On the one hand, it can model tunnels, caves and overhangs, and terrain features can be captured with pixel-perfect accuracy. On the other hand, it is not demanding regarding processing and storage requirements and offers scalability. Finally, rendering, physics and dynamic updates can be performed in real-time.As a result, this work represents a significant contribution, offering an integrated solution capable of addressing the most challenging aspects of dynamic terrains. Our approach introduces a novel terrain model comprising diverse data structures and a suite of algorithms designed to capture a wide range of terrain formations accurately. A scene composed of tens of millions of triangles can be continuously updated to the extent of simulating a completely devastated terrain, rendered, and subjected to real-time physics computations involving tens of thousands of physical entities. The proposed model holds great potential for computer graphic applications, particularly in scenarios such as simulators and games, where dynamic landscapes play a paramount role.
  

DOCTORAL DEGREE IN CONSTRUCTION ENGINEERING

• JATIVA GUZMAN, ANDRES: APLICABILIDAD DE LA CENIZA VOLCÁNICA DE BAJA ACTIVIDAD COMO NUEVO RECURSO PARA MATERIALES CEMENTICIOS SOSTENIBLES.
  
  Author: JATIVA GUZMAN, ANDRES
  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: (DECA)
  Mode: Normal
  Deposit date: 03/04/2024
  Reading date: 29/05/2024
  Reading time: 11:00
  Reading place: Sala C1002 Edifici C1, Escola de Camins (ETSECCPB)- Campus Nord 08034 Barcelona
  Thesis director: ETXEBERRIA LARRAÑAGA, MIREN
  Committee:
       PRESIDENT: MAURY RAMIREZ, ANIBAL CESAR
       SECRETARI: CASANOVA HORMAECHEA, IGNACIO
       VOCAL: GIRÓ PALOMA, JESSICA
  Thesis abstract: Volcanic ash (VA), abundantly available in various regions globally, serves as an effective supplementary cementitious material (SCM) for partially substituting Portland cement (OPC). However, its inherently low reactivity presents a challenge for its broader utilization. This challenge can be overcome by enhancing VA's reactivity via several approaches: 1) employing mechanical and thermal treatments; 2) adding alkali activators; 3) using corrective additives to balance VA's chemical shortcomings; and 4) applying appropriate curing methods to stimulate pozzolanic reactions.According to ASTM C618 standards, VA falls into the Class N category. The study explored various activation strategies, including VA calcination (CVA) at temperatures ranging from 500 to 900 °C, alkali activation using Na2SiO3 (NSi), CaCl2 (CaCl), Na2SO4 (NS), and Na2CO3 (NC) at 1 to 4% dosages (relative to binder weight), and the strategic inclusion of SCMs like lime (L), fly ash (FA), and slag (EC) in amounts of 10, 20, and 30% (relative to VA weight). The curing process's influence was examined under different conditions: moist and heated environments (40 and 70°C for 3 days). The best mortar mixes underwent evaluations for compressive strength at intervals of 7, 28, and 90 days, alongside assessments of physical characteristics (e.g., porosity, water absorption, density) and microstructural properties. The mortars' durability was further gauged through shrinkage and acid resistance tests (against HCl, H2SO4, HNO3).For mortars comprising 35% VA (VA35) and subjected to moist curing, calcining VA at 700 °C coupled with a 20% lime addition resulted in achieving mortars boasting a peak strength of 49 MPa at 28 days, alongside a 9% reduction in water absorption compared to mortars with unmodified VA (VA35). Similarly, employing alkali activators, particularly NSi and CaCl at 1% and 2% dosages respectively, led to mortars demonstrating superior mechanical and physical properties.In mortars with a 50% VA content, the optimal alkali activator dosages were identified as 2% for NSi and 1% for CaCl. The addition of 20% FA and 10% EC emerged as the most effective corrective additives. Thermal curing (70°C for 3 days) significantly boosted early strength gains, curtailed mortar shrinkage, and enhanced resistance to H2SO4, especially notable in mortars prepared with CVA and 1% CaCl. Notwithstanding, at the 90-day mark, moist chamber curing was found to facilitate greater strength increases. A specific mix utilizing mixed activation (1% CaCl with CVA and 10% EC) notably outperformed, achieving 56 MPa, which is a 32% improvement over mortars with untreated VA (VA50). The presence of hydrated phases (C-S-H/C-S-A-H) and minerals such as portlandite, strätlingite, kuzelite, and Friedel's salt attested to the mortars' commendable performance.For mortars containing 75% VA, the best results were achieved with 2% NSi and 1% CaCl as activators, and the addition of 10% FA and 10% EC as correctives additives. Under moist curing, a mixed-activated mortar (1% CaCl-CVA-10%EC) exhibited the highest compressive strength at 90 days, reaching 44 MPa¿a 29% increase over mortars with untreated VA (VA75). Thermal curing expedited early strength development, minimized shrinkage, and bolstered resistance to H2SO4, along with improving porosity and water absorption rates, with the exception of CaCl-containing mortars. Notably, the VA75 mix showed limited portlandite formation and an absence of strätlingite.This investigation confirms the feasibility of achieving satisfactory compressive strengths in mortars with high VA content. Furthermore, by leveraging the studied activation and curing techniques, it's possible to tailor the mortar mix for specific applications, optimizing for properties such as minimal shrinkage, reduced water absorption, enhanced early-age strength, or heightened resistance to particular acid exposures.
  
• LIPA CUSI, LEONEL: Metodología numérica automatizada para la evaluación de la respuesta dinámica de construcciones prehispánicas de piedra de junta seca en el Perú.
  
  Author: LIPA CUSI, LEONEL
  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: (DECA)
  Mode: Change of supervisor
  Deposit date: 03/04/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: PELA, LUCA | TARQUE, SABINO NICOLA
  Committee:
       PRESIDENT: GOICOLEA RUIGÓMEZ, JOSÉ MARÍA
       SECRETARI: ROCA FABREGAT, PEDRO
       VOCAL NO PRESENCIAL: SALOUSTROS, SAVVAS
       VOCAL NO PRESENCIAL: SANTA CRUZ HIDALGO, SANDRA CECILIA
       VOCAL NO PRESENCIAL: SANDOVAL MANDUJANO, CRISTIAN
  Thesis abstract: The study and the conservation of stone heritage is a global concern, mainly when these constructions are in seismic zones. Due to its great cultural and historical diversity, Peru has many stone constructions in different archaeological sites, covering different construction typologies. Unfortunately, many of these constructions have not yet been structurally evaluated, so their structural behaviour is unknown. In addition, there is no classification of the stone structural typologies (taxonomy), so the different characteristics of existing constructions are unknown. One way to study the non-linear dynamic behaviour of these stone structures is to use a rigorous -but fast- numerical methodology to adequately reproduce the different failure mechanisms based on the dynamics of rigid bodies within the finite element method.Then, this work presents a taxonomic classification of prehispanic stone constructions in Peru, derived from a field study, as the first contribution. Based on this taxonomy, several archaeological sites in Puno and Cusco were classified, and the most common typologies of these regions were identified. The research also proposes novel algorithms developed in Python to obtain the geometric model of dry-joint stone structures using images taken by a camera, a mobile phone, or an existing photograph (including identification of stones and joints, named image segmentation). These routines allow the creation of a 3D model of each block (stone), assembling them, and exporting them to a finite element program for further evaluation.Regarding developing a numerical methodology, the dynamic of rigid bodies within the finite element method is proposed here. Each stone block is considered a rigid body interconnected with other blocks through nonlinear interfaces. This methodology was validated using Abaqus, based on the results of experimental tests developed in this thesis. The experimental campaign was carried out on three walls built with concrete blocks, simulating the geometry of the Inca structures. The walls were built on a tilting table and tested by rotating them out of the plane of the wall. Then, numerical models of the tests were developed by considering each stone as a rigid body and calibrating the contact properties to simulate the experimental behaviour correctly. The numerical results in weight, collapse angle, relative displacements at different points of the structure and collapse mechanisms were very similar to those obtained in the experimental campaign.As a case study, a section of an Inca stone wall from Sacsayhuaman, Cusco, was numerically evaluated using various seismic records. The complete geometric model of the stone wall was automatically obtained using the Python routines. Furthermore, discrete element particles represented the soil behind the wall. The properties of the numerical model were obtained from the experimental campaign, and the predominant frequencies of the structure were obtained using the vibration approach. As a result, the structure can adequately support these seismic records scaled up to a peak acceleration of 0.1 g. However, it suffers significant residual displacements for scaled records greater than 0.2 g.The proposed numerical methodology allows the rigorous evaluation of dry-jointed stone structures, knowing if the structure should be intervened to ensure its functionality. Therefore, it is expected that the results of this research will be used to study other stone constructions, opening possibilities for improving the methodology for different structural configurations.
  

DOCTORAL DEGREE IN ELECTRICAL ENGINEERING

• BAS CALOPA, PAU: Partial discharges in low-pressure atmosphere: an experimental approach to improving electrical protection
  
  Author: BAS CALOPA, PAU
  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: (DEE)
  Mode: Article-based thesis
  Deposit date: 21/03/2024
  Reading date: 06/05/2024
  Reading time: 11:00
  Reading place: Edifici TR5, sala conferències, ESEIAAT-UPC
  Thesis director: RIBA RUIZ, JORDI ROGER | MORENO EGUILAZ, JUAN MANUEL
  Committee:
       PRESIDENT: MONTAÑA PUIG, JUAN
       SECRETARI: ABOMAILEK RUBIO, BASEL CARLOS
       VOCAL: URRESTY BETANCOURT, JULIO CÉSAR
  Thesis abstract: This thesis contributes to the field of partial discharges in low-pressure environments, aiming to improve electrical wire interconnecting systems (EWIS) protection in aerospace applications. A series of experimental studies have been conducted to evaluate the potential of corona and surface discharges as indicators of electrical insulation degradation. To this end, the influence of variables such as pressure, pressure drop, frequency, and geometry on corona discharge behaviour has been examined. Furthermore, the performance of various sensors, including CMOS image sensors, photoelectric UV sensors, and acoustic cameras, in detecting corona discharges has been investigated and compared. Additionally, by employing RGB image processing techniques, this thesis presents a novel method for the quantification of corona discharges. This method allowed studying the correlation between the light intensity of electrical discharges and the dissipated electrical energy, with a particular focus on how pressure and frequency variation impacts on this relationship. The feasibility of utilizing corona and surface discharges as an indicator for the degradation of wire insulation has also been explored, providing foundational knowledge for the future development of electrical protection tools aimed at predictive maintenance. The findings from this research contribute to the advancement of predictive maintenance strategies, offering potential for early detection of insulation failures, thereby enhancing the safety and reliability of aerospace electrical systems.
  

DOCTORAL DEGREE IN ELECTRONIC ENGINEERING

• COLL VALENTÍ, ARNAU: Advanced c-Si solar cell structures: application of laser processes and optical nanostructures
  
  Author: COLL VALENTÍ, ARNAU
  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: 08/03/2024
  Reading date: 26/04/2024
  Reading time: 11:00
  Reading place: Defensa: Aula de Postgrau, edifici C5-116, ETSETB
  Thesis director: BERMEJO BROTO, ALEXANDRA | MARTIN GARCIA, ISIDRO
  Committee:
       PRESIDENT: VOZ SANCHEZ, CRISTOBAL
       SECRETARI: GARIN ESCRIVA, MOISES
       VOCAL: HERNÁNDEZ GARCÍA, DAVID
  Thesis abstract: This thesis works towards efficient and cost-effective methods to improve the performance of thin silicon solar cells. Focusing on two principal objectives, the Thesis develops novel techniques to enhance the production of colloidal crystals and the possibility to apply these crystals to improve the light trapping efficiency, as well as creating a unique structure for lased doped solar cells. Both advancements focus on improving the production solar cells using low-temperature processes and thin wafers, thus circumventing the dependences of high temperature procedures, while bolstering light trapping capabilities. This approach is motivated by the restarting trend to reduce silicon wafer thickness, therefore this work is pushed by the need to overcome the actual technical and physical constrains. The initial part of the Thesis focuses on the implementation of an electrospray system for the creation of colloidal crystals. These colloidal crystals are intended for application as photonic light trapping structures in solar cells. Afterwards, these structures are tested within a laser firing process to double check the viability to be used within the laser firing technique commonly used in solar cell fabrication.The main achievements within the electrospray deposition technique are the development of polystyrene and SiO2 colloidal crystals with areas in the range of 1-2cm2 and up to 17 layers of ordered particles while keep good optical quality. These layers are created at room temperature and with a process that could be adapted to batch processing and parallelized to increase the area. The technique has also been adapted to be used in non-even surfaces like C-Si pyramids or black silicon. At the same time, these structures had been used to create inverse colloidal crystals from Al2O3 and Al2O3 /TiO2 shells while getting rid of polystyrene nanoparticles. The final Al2O3 /TiO2 structure obtains high reflectivity values up to 98.2%. Finally, these inverse opals are created on top of Al2O3 passivated C-Si wafers. These structures are able to withstand a laser firing process while keeping the passivation, demonstrating the capability to be used with in the solar cells fabrication process.The second part of the thesis focuses in the creation of a process to achieve low temperature solar cells by means of highly-doped regions that are punctually defined through laser processed dielectric films. This technique call ¿DopLaCell¿ stand for doped by laser solar cell. In the initial stages of the process and as a proof of concept, 1x1 cm2 solar cells were created on both p- and n-type substrates with efficiencies of 11.6% and 12.8% respectively. In a second step, 1x1 cm2 n-type c-Si solar cells are created using the ¿cold¿ p+ emitters used in the ¿DopLaCell¿ structure. This second batch of solar cells uses a Heterojunction with Intrinsic Thin layer (HIT) in the front face. This approach avoids the use of Transparent Conductive Oxide (TCO) on the back side of the cell thus improving the reflectivity especially with IR photons. These cells reach efficiencies up to 18.1%. Finally the process is being improved towards a pure texturized ¿DopLaCell¿. In this final step, totally ¿cold¿ 2x2 cm2 solar cells are fabricated with and efficiency up to 17.0 % .This work represents a one big step forward towards a future path of thin silicon solar cells fabrication, addressing the actual technology limitations and enabling the possibility to overcome the principal issues. This research lays the ground towards thin, affordable and efficient solar cells improving the path towards a more viable and eco-friendly energy future
  
• RALLIS, KONSTANTINOS: Novel Nanoelectronic Circuits and Systems
  
  Author: RALLIS, KONSTANTINOS
  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: 13/03/2024
  Reading date: 09/05/2024
  Reading time: 11:00
  Reading place: ETSETB - Multimedia room Building B3 at Campus Nord UPC
  Thesis director: RUBIO SOLA, JOSE ANTONIO | SIRAKOULIS, GEORGIOS
  Committee:
       PRESIDENT: JIMÉNEZ JIMÉNEZ, DAVID
       SECRETARI: ABADAL CAVALLÉ, SERGI
       VOCAL: CUCU LAURENCIO, NICOLETA
  Thesis abstract: Lately, in the rise of the era of 2D materials, Graphene is one of the materials that has been extensively investigated for its possible integration in computing devices and thus computing circuits. This is mainly attributed to its very wide set of appealing properties. The combination of its electronic properties with others, such as mechanical, optical or chemical properties, can extend the range of use of computing devices and lead to groundbreaking interdisciplinary applications. However, this integration of Graphene in switching and computing elements is not easy. In this dissertation, the Non-Equilibrium Green's Function method (NEGF), along with the Tight Binding Hamiltonians, are fitted on experimental data from fabricated Graphene devices. Although as a computational method, NEGF is appropriate for the simulation of small-scale devices in the regime of nanometers, its ability to be efficiently expanded for the description of larger devices is presented. The aforementioned electronic properties of the material are highly related to its shape and structure. Consequently, it requires a very precise fabrication method that can guarantee the minimum presence of defects on the Graphene grid. For that reason, the effect of defects is deeply investigated. The NEGF method is further enhanced in order to be able to incorporate lattice defects. The most common lattice defects are included, meaning the single and double vacancy. A framework has thus been created, so that for the first time the user can select areas of interest on the grid, in which the defects will be concentrated. Those concentrations can also be variable. Moreover, an extensive study is conducted on defective grids with different concentrations of single and double vacancies. The investigated grids are non-rectangular and have regions with different widths. The effect of those vacancies on the electronic properties of Graphene is investigated, and more specifically their effect on the conductance and the energy gap of the device, as well as the effect on circuit-centered characteristics such as the leakage current and ON/OFF current ratio. Having a functional, robust, versatile, and accurate model, the focus of this thesis is extended to the level of circuits. The model is imported into SPICE through Verilog-A. In this part, the thesis emphasizes on the investigation of the switching capabilities of L-shaped Graphene Nanoribbons (GNRs). These structures have been proven to be able to operate as switches, without the use of a back gate, and here, the properties that are dependent on their dimensions are explored and optimized for the first time. The optimized structures are then used for the realization of a set of computing topologies. Initially, a novel area-optimized 2-branch comb-shaped topology is introduced for the realization of a universal computing set that consists of an AND, OR, NOT gate, and a Buffer. All these logic operations can be mapped on the same topology through appropriate biasing. Then, an extension of this, the 3-branch comb-shaped topology is proposed, which is able to operate as a 2-XOR, 3-XOR and 3-MAJ gate. The circuit of a 1-bit full adder, is also presented. For the evaluation of the performance of the topologies, several related metrics are employed such as the area, delay, power dissipation and the power-delay product. The operation of these topologies relies of the principles of Pass Transistor Logic (PTL) and reconfigurable computing. Finally, in an attempt to go beyond the conventional Boolean logic, the compliance of Graphene with Multi-Valued Logic (MVL) circuits and applications is investigated. The ability of a Graphene Quantum Point Contact (G-QPC) device to encode the digits of the radix-4 numeral system is presented and as a proof of concept, the operation of an arbitrary radix-4 adder is explained.
  

DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING

• KILIÇ, EYLEM: Advancing the use of waste streams in plastic composites
  
  Author: KILIÇ, EYLEM
  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: (DECA)
  Mode: Article-based thesis
  Deposit date: 18/03/2024
  Reading date: 30/05/2024
  Reading time: 12:00
  Reading place: Place: ETSECCPB UPC, Campus Nord Building C1. Classroom: 002 C/Jordi Girona, 1-3 08034 Barcelona
  Thesis director: PUIG VIDAL, RITA | FULLANA PALMER, PERE
  Committee:
       PRESIDENT: MÉNDEZ GONZÁLEZ, JOSÉ ALBERTO
       SECRETARI: GASSO DOMINGO, SANTIAGO
       VOCAL NO PRESENCIAL: EL BACHAWATI, MAKRAM
  Thesis abstract: The leather industry faces global challenges related to its sustainability credentials due the significant waste generated throughout the leather production processes. In the context of contemporary environmental policy, which is increasingly focused on sustainable production and consumption, the need to understand and mitigate environmental impacts associated with leather has become a strategic and economic imperative. In this respect, a comprehensive "gate-to-gate" life cycle assessment (LCA) was conducted following the newly released Leather Product Environmental Footprint Category Rules (PEFCR). The analysis aimed to evaluate the environmental impacts of leather production, with a specific focus on New Zealand's leather production industry, mainly due to its agriculturally oriented economy and large size of livestock sector.This thesis builds upon this foundation by addressing the issue of solid waste in the leather industry. Therefore, a waste valorization strategy was investigated to convert unavoidable waste into valuable resources through the production of new, value added composites, which involves incorporating leather waste (BF) into virgin and recycled high-density polyethylene (HDPE). The focus of this thesis is to analyze environmental impact of these novel composites, to improve the implementation of circular economy principles, within the context of their use in automotive bumper production. The environmental impact of these novel composites was compared to conventional polypropylene (PP), bumpers, by performing a cradle-to-gate life cycle assessment (LCA). The thesis also aims to provide a contribution to LCA methodology applied to composite materials, by adopting various functional units, such as mass, volume, and the volume of raw material fulfilling a specific impact strength requirement.The in-depth analysis of mechanical and thermal properties of the BF/HDPE composites highlights the composite¿s potential for industrial applications that require high mechanical strength and low thermal conductivity. The incorporation of leather waste not only enhances material properties, but also contributes to environmental sustainability by converting unavoidable waste into a value added product. The environmental assessment, adopting a cradle-to-gate LCA with various functional units, indicates that composites made from recycled HDPE and leather waste have a lower environmental impact than those from virgin materials. The only exception is when the material's impact strength is a key factor in the functional unit, due to the higher impact strength of HDPE-BF composites. In all cases, increasing the content of recycled materials in the bumpers increases its environmental performance, supporting the advancement of circular economy principles in the automotive sector.The research highlights the significance of choosing an appropriate functional unit, based on specific applications such as automotive bumpers, in comparing the environmental footprint of innovative composite materials with that of traditional materials. Broadening the scope of evaluation to include various functions yields a more realistic scenario, but it leads to higher uncertainties in the results as well.
  

DOCTORAL DEGREE IN MATERIALS SCIENCE AND ENGINEERING

• GORDON POZUELO, SANDRA: Mechanical integrity of coated PcBN systems: Mechanics and mechanisms involved under service-like conditions
  
  Author: GORDON POZUELO, 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 MATERIALS SCIENCE AND ENGINEERING
  Department: (CEM)
  Mode: Article-based thesis
  Deposit date: 19/02/2024
  Reading date: 10/05/2024
  Reading time: 11:00
  Reading place: EEBE (Escola d'Enginyeria Barcelona Est), Aula A2.14, planta 2, Campus Diagonal-Besòs
  Thesis director: LLANES PITARCH, LUIS MIGUEL | ROA ROVIRA, JOAN JOSEP
  Committee:
       PRESIDENT: MARI, DANIELE
       SECRETARI: FARGAS RIBAS, GEMMA
       VOCAL: BOTERO VEGA, CARLOS ALBERTO
  Thesis abstract: Polycrystalline cubic boron nitride (PcBN) is a composite competitive cutting tool material that excels performance when machining difficult-to-cut materials (e.g. hardened steels, superalloys, etc) due to its exceptional mechanical properties. In practice, PcBNs are coated with a ceramic film to prevent and prolong the onset of tribo-oxidation and abrasive wear. Although there is not a unique consolidated opinion regarding the benefits of coatings in PcBN, most of the bibliography agrees on their use when involving hard turning operations. Most of the research address the tool performance and wear mechanisms, whereas information involving materials science aspects of PcBN and coated PcBN tools, on the basis of understanding microstructure ¿ mechanical properties correlations, is quite limited. In this regard, this thesis focusses on studying hardness, fracture toughness and wear resistance as they are key mechanical properties controlling the mechanical integrity and reliability of the tool, which are related with the contact response, fracture resistance (e.g. premature chipping) and effective tool life, respectively. Four distinct substrates of the coated PcBN grades are studied and first characterized, including the development of characterization and testing protocols. In doing so, focus ion beam tomography and three-dimension (3D) image reconstruction was implemented to study the bulk microstructural characteristics of a PcBN grade with high cBN content and metallic binder. It was found to be a powerful and useful method to gain in-depth knowledge and understanding the microstructural characteristics of PcBN composite materials, additionally to those gathered by conventionally 2D method. The study then focuses on the assessment of the micromechanical properties of PcBN composite materials, as they are known to be key for optimizing their performance through microstructural design. High-speed nanoindentation is successfully implemented to characterize and correlate microstructure with local mechanical properties of such hard and stiff composite materials; where two different methodologies, 1D and 2D Gaussian, are used for statistically deconvoluting the data. It is found that the harder PcBN grade is clearly related with the high cBN content. A scaled-up method was employed to evaluate the contact response of uncoated PcBN grades. The higher cBN content and metallic binder grade, exhibits higher resistance to crack nucleation and a more gradual transition through different damage scenarios due to the concomitant increase of hardness and fracture toughness of this grade. Regarding fracture toughening mechanisms, crack path changes from propagation across the ceramic binder to transgranular fracture through cBN particles, as the cBN content increases. Very interesting, fracture toughness is enhanced by crack interaction with intrinsic sub-grained or twin boundaries within the individual cBN particles as well as by crack deviation through nano cBN particles dispersed in the binder. Afterwards, research was aimed to characterize coated PcBN (with different chemical nature and bias voltage), mainly in terms of coating adhesion strength and mechanical integrity of bulk coated systems as a function of the PcBN substrate microstructural assemblage. Mechanical response of the coated system, assessed by using Rockwell C indentation technique and scratch testing, is strongly dependent on the underneath substrate microstructural assemblage; and therefore, its different intrinsic hardness-toughness correlation. Finally, TiAlN-coated PcBN inserts were used to mill a hardened cold work tool steel. It was proposed as an exploratory study of milling performance of coated PcBN systems to assess the onset of coating failure without involving the emergence of other wear phenomena (e.g. thermally-driven ones).
  
• JOHANSSON, LINH HA HUONG LOVISA: 3D-printed biomimetic bone grafts: Clinical validation and improvement strategies
  
  Author: JOHANSSON, LINH HA HUONG LOVISA
  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: (CEM)
  Mode: Normal
  Deposit date: 26/03/2024
  Reading date: 06/05/2024
  Reading time: 10:00
  Reading place: EEBE (Escola d'Enginyeria Barcelona Est), Aula A0.02, Edifici A, planta 0, Campus Diagonal-Besòs.
  Thesis director: GINEBRA MOLINS, MARIA PAU | RAYMOND LLORENS, SANTIAGO
  Committee:
       PRESIDENT: MONTERO MARTÍN, JAVIER
       SECRETARI: DÍEZ ESCUDERO, ANNA
       VOCAL: OLDE DAMINK, LEON
  Thesis abstract: Bone defects pose a major clinical and socio-economic burden and there is a clear need for new bone grafting strategies that take into account the physical-chemical properties of the native bone, to help treat bone defects in a time- and cost-effective way.Autografts are considered the gold standard due to their biological performance, however, additional surgical procedures for bone harvesting poses drawbacks. For this reason, the industrial- and scientific communities have focused on the development of synthetic bone grafting solutions. The present PhD thesis advances in the development of biomimetic personalised bone grafting solutions, including the clinical validation and the development of new material formulations with improved mechanical performance. Chapter 1: Gives an insight into the general context of bone regeneration and the materials used as bone substitutes, emphasising the need for innovative personalised synthetic bone grafts. This chapter offers an overview of additive manufacturing techniques and frequently employed ceramics in bone tissue engineering and their consolidation strategies. Further, a global presentation is given on their clinical translation, especially emphasising calcium phosphates and MimetikOss® 3D. Chapter 2: Focuses on evaluating the clinical performance of the 3D-printed bone graft MimetikOss® 3D in a horizontal vestibular augmentation. The ridge in the anterior maxilla is reconstructed with a synthetic patient-specific bone graft with a staged approach for dental implant placement. 3D-printed bone grafts permit a perfect fit in the surgical site without any additional shaping, which reduces surgery time compared with other bone augmentation techniques (e.g., guided bone regeneration, standard blocks). The bone graft is completely osseointegrated and its macropores colonised by newly formed bone at 10-months post-surgery without signs of encapsulation. A stable bone gain is achieved, resulting in a fully restored bone width. Dental implants were placed without the need for regrafting and stayed stable at 1- year post-loading, demonstrating the clinical relevance of these bone grafts in vestibular bone augmentations. Chapter 3: Encompasses two routes for incorporating PLGA, as a binder or as a coating, to 3D-printed self-setting scaffolds, taking advantage of their low-temperature hardening, to enhance their mechanical performance. The addition of PLGA increases the capacity for plastic deformation, which significantly improves their toughness (by a 2.6-fold and 4.2-fold change in flexion for PLGA as a binder and as a coating, respectively; and by an 8-fold and 1.6-fold change in compression, respectively), while preserving the in vitro cell viability of MimetikOss® 3D (with MG-63 and hMSC cells). The configuration with PLGA as binder is the better option regarding the enhancement in mechanical performance and osteogenic differentiation (2-fold and 1.5-fold change increase for ALPL and RUNX2 expressions, respectively). Screwability tests demonstrate that the enhanced mechanical properties increase the fixability of the scaffolds in a complex fixation indication in the jaw. Chapter 4: Discusses the impact, limitations, and challenges of 3D-printed biomimetic bone grafts and emphasises the steps remaining before transferring the new technology to the market. It is shown that the developments made in this PhD thesis can be beneficial for the patients and have a positive impact on society. Composite patient-specific bone grafts have an impact on cost, time and performance of the future bone grafting solutions, and they strive towards added value in personalised medicine. This will help treat complex and large bone defects in a way that benefits both the clinician and the patient and encourages sustainable healthcare based on synthetic biomaterials. This technology was protected by a filed patent application, however, there is still work left before it can be translated to the market.
  

DOCTORAL DEGREE IN PHOTONICS

• DÍEZ MÉRIDA, JAIME: Probing Magic-Angle Twisted Bilayer Graphene with Gate Defined homo-Junctions
  
  Author: DÍEZ MÉRIDA, 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 PHOTONICS
  Department: Institute of Photonic Sciences (ICFO)
  Mode: Normal
  Deposit date: 09/04/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: EFETOV, DMITRI | LEWENSTEIN, MACIEJ
  Committee:
       PRESIDENT: WEITZ, THOMAS
       SECRETARI: RUBIO VERDÚ, CARMEN
       VOCAL: RIBEIRO PALAU, REBECA LISSETTE
  Thesis abstract: In 2018, following a theoretical prediction from 2011, it was found that stacking two layers of graphene with a relative twist angle of 1.1° between them leads to multiple new properties. At this so-called magic angle, the electronic band structure of the material reconstructs, creating a narrow flat band at the Fermi level. The formation of a flat band enhances electron-electron interactions, resulting in the emergence of states of matter not present in the original graphene layers, including correlated insulators, superconductivity, ferromagnetism and non-trivial topological states. The understanding of the origin of these correlated states could help unravel the physics of highly correlated flat band systems which could potentially provide key technological developments. The main objective of this thesis is to study magic-angle twisted bilayer graphene (MATBG) by creating monolithic gate-defined Josephson junctions. By exploiting the rich phase space of the material, we can create a Josephson junction by independently tuning the superconductor and the weak link state. Studying the Josephson effect is a first step towards understanding fundamental properties of a superconductor, such as its order parameter. First, we have optimized the fabrication of these gate-defined junctions made of all van der Waals materials. We have made double-graphite-gated hBN encapsulated MATBG devices where the top gate is split into two parts via nanolithography techniques. This configuration allows to independently control the three regions of the Josephson junction (superconductor, weak-link and superconductor). Then, we have studied the gate-defined Josephson junctions via low-temperature transport measurements. After demonstrating the Josephson effect in the fabricated devices, we focus on the behavior of one of these junctions in great detail. In particular, we have observed an unconventional behavior when the weak link of the junction is set close to the correlated insulator at half-filling of the hole-side flatband. We have observed a phase shifted Fraunhofer pattern with a pronounced magnetic hysteresis, characteristic of magnetic Josephson junctions. To understand the origin of the signals, we have performed a critical current distribution Fourier analysis as well as a tight binding calculation of a MATBG Josephson junction. Our theoretical calculations with a valley polarized state as the weak link can explain the key signatures observed in the experiment. Lastly, the combination of magnetization and its current-induced magnetization switching has allowed us to realize a programmable zero-field superconducting diode.Finally, we have shown the flexibility of these devices by studying a MATBG p-n junction under light illumination. We have studied the relaxation dynamics of hot electrons using time and frequency-resolved photovoltage measurements. The measurements have revealed an ultrafast cooling in MATBG compared to Bernal-bilayer from room temperature down to 5 K. The enhanced cooling in MATBG can be explained by the presence of the moiré pattern and corresponding mini-Brillouin zone. In summary, we have demonstrated that by integrating various MATBG states within a single device, we can gain a deeper insight into the system's properties and can engineer innovative, complex hybrid structures, such as magnetic Josephson junctions and superconducting diodes.
  

DOCTORAL DEGREE IN POLYMERS AND BIOPOLYMERS

• FERRERES CABANES, GUILLEM: Hybrid metal-organic nanoparticles for antimicrobial applications
  
  Author: FERRERES CABANES, GUILLEM
  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: 03/04/2024
  Reading date: 21/06/2024
  Reading time: 11:00
  Reading place: Sala de Conferències de l' ESEIAAT (Escola Superior d¿Enginyeries Industrial, Aeroespacial i Audiovisual de Terrassa), C/ Colom, 1-11, 08222 Terrassa.
  Thesis director: TZANOV, TZANKO | TORRENT BURGUES, JUAN
  Committee:
       PRESIDENT: PASHKULEVA, IVA HRISTOVA
       SECRETARI: GARRIGA SOLE, PERE
       VOCAL: VASSILEVA, ELENA
  Thesis abstract: Antimicrobial resistance (AMR) is a global health concern, which leads to increased morbidity and mortality, huge economic burden to the healthcare systems and potentially untreatable infections. Due to the inappropriate use of antibiotics, the natural adaptation has been accelerated and bacteria have developed multiple ways to degrade, alter, or expel drug molecules. Besides these resistance mechanisms, bacteria can adhere to surfaces and grow as biofilms ¿ organised assemblies of surface-bound cells, enclosed in a self-produced extracellular polymer matrix (EPM). The EPM holds the pathogens together, enables adhesion to surfaces, and enhances the tolerance to host immune responses and antibiotics compared to free-floating cells. Metal nanoparticles (NPs) have been suggested as a potential solution to fight resistant bacteria due to their strong antimicrobial activity and versatile mechanisms of action. However, inherent toxicity towards mammalian cells and large variation of physical properties are challenges that preclude the clinical application of such materials. In this thesis, metal NPs have been combined with different biomolecules for enhanced biocompatibility, increased antimicrobial efficacy, and enabling new functionalities to mitigate AMR.The first part of the thesis describes the formation of Ag NPs using bioactive macromolecules to produce multifunctional nanostructures. First, the matrix-degrading enzyme (MDE) ¿-amylase was used to reduce Ag(I), yielding NPs with antimicrobial and biofilm-degrading activity towards both gram-positive and gram-negative bacteria. Then, chitosan-Ag NPs were decorated with the quorum-quenching enzyme (QQE) acylase I, which combination was able to kill Pseudomonas aeruginosa, hinder biofilm formation, and inhibit bacterial quorum sensing (QS) based on acyl homoserine lactones (AHLs). Finally, adipic acid dihydrazide (ADH) was grafted on hyaluronic acid (HA) and used to form Ag NPs. The modified polymer (HA-ADH) played a crucial role in the interaction of the NPs with bacterial membranes, assessed using Langmuir isotherms, and reduced the toxicity of Ag towards human cells. In the second part of the thesis, HA-ADH and epigallocatechin gallate (EGCG) were used to produce nanostructured complexes with a scarcely studied antimicrobial Co(II). On one hand, Co(II) formed a complex with the biopolymer, which complex was transformed to antimicrobial nanogels (NGs) using an ultrasonic approach. On the other hand, incubation of EGCG with Co(II) yielded nanostructured metal-phenolic networks (MPN). These cobalt-containing NPs were active towards both gram-positive and gram-negative bacteria, and were able to inhibit biofilm formation due to the capacity of ECGC to disrupt QS. The last chapter of the thesis validates the use of the novel nanomaterials for antimicrobial functionalisation of medical devices. Coating of contact lenses with NGs hindered bacterial colonisation and unspecific absorption of proteins without affecting the optical properties and comfort of the material. Inclusion of MPN NPs in thiolated hyaluronic acid (THA) hydrogels endowed these materials with properties promoting efficient chronic wound treatment. The antibiotic-free hydrogels were able to control the main factors of wound chronicity by inhibiting the activity of deleterious wound enzymes, scavenging reactive oxidative species, and demonstrating pronounced antimicrobial activity, resulting in similar to commercial products wound management efficacy confirmed in vivo.
  
• MARTÍ BALLESTÉ, DÍDAC: Advanced molecular modelling techniques for immunosensor nanointerfaces
  
  Author: MARTÍ BALLESTÉ, DÍDAC
  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: 13/03/2024
  Reading date: 03/06/2024
  Reading time: 11:30
  Reading place: Sala Polivalent de l'Edifici I, Edifici I, planta baixa, Campus Diagonal-Besòs
  Thesis director: TORRAS COSTA, JUAN | ALEMAN LLANSO, CARLOS ENRIQUE
  Committee:
       PRESIDENT: POATER TEIXIDOR, ALBERT
       SECRETARI: SASSELLI RAMOS, IVAN
       VOCAL: CREHUET SIMON, RAMON
  Thesis abstract: Viruses and their infections have always affected human lives throughout history. Globalization contributed positively to the progress of human society in science and medicine which permited to deal with viruses, but the reality is that the number of infections does not decrease over the years. Globalization itself is here agin one of the main factors, as people move in more densely populated areas, which favors the spread of viruses. Another important factor is the viruses themselves, which over the years have shown a constant evolution that allowed them to adapt to new hosts. For these reasons, human-led efforts such as vaccines, antiviral treatments, sensors etc. are critical tools for human survival, and like viruses, humans must continue to innovate. This thesis focused on providing different understandings of a series of biochemical processes at molecular the level to facilitate the design of plasmonic resonance sensors, currently used for detecting diseases such as cancer, to enable a similar detection improvement in other viruses and diseases such as HIV and SARS-Cov-2.This thesis is divided into two parts, with the first focusing on the characterization related to the HIV virus. Several studies have been carried out using a combination of different molecular simulation techniques, classical dynamics, quantum mechanics and hybrid QM/MM-MD methods. These studies characterize the behavior of the antibody chosen in the design of the sensor, IgG1 , as well as its interactions with the silica surface that compounds the sensor and its orientation once functionalized on top of the surface. Additional studies were performedm focusing on the interaction between the immunoglobulin G and the glycoprotein that forms part of the HIV virus spike, and permited to identify the interactions helping the antibody to attach to the virus for the virus inhibition.In the second part, the same molecular simulation techniques have been used to study the virus which completely changed the world in 2020, SARS-CoV-2 known for the disease COVID19. As this virus was new at the time of the thesis, there was a dramatic lack of knowledge. Molecular modelling techniques were used to study the behavior of the virus spike in presence of heat or solvated in water. Similar studies to the case of HIV-IgG1 were performed between SARS-CoV-2 spike and different promising antibodies with the goal to identify the best candidate for sensor functionalization or virus inhibition. In this section, the interaction between the virus spike and the ACE2 enzyme, the target cell that SARS-CoV-2 use to infect human body, was also characterized. Finally, new antibodies were designed combining the previous ones with IgG1 and their behavior was studied in the presence of the sensor¿s silica surface and the nanoparticles gold surface used in the detector
  

DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS

• MAJORAL RAMONEDA, MARC: A Flexible System-on-Chip FPGA Architecture for Prototyping Experimental GNSS Receivers
  
  Author: MAJORAL RAMONEDA, MARC
  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: 03/04/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: FERNANDEZ PRADES, CARLOS | ARRIBAS LÁZARO, JAVIER
  Committee:
       PRESIDENT: CAPARRA, GIANLUCA
       SECRETARI: BARTZOUDIS, NIKOLAOS
       VOCAL: FONT BACH, JOSEP ORIOL
  Thesis abstract: The rapid evolution in satellite navigation technology (GNSS) requires advanced prototyping tools for exploring new signals and developing innovative systems. Prototyping is essential in the design and development process, as it allows researchers to test and refine their ideas before implementing them on a large scale.Prototyping using commercial GNSS receivers poses several challenges. Currently, these receivers are primarily based on application-specific integrated circuits (ASICs), which are characterized by low power consumption, compact dimensions, and low cost, but offer limited flexibility. Although some commercial devices incorporate software-defined radio (SDR) techniques, they often contain proprietary code that restricts reconfiguration through an application programming interface (API) established by the manufacturer.GNSS receivers based on free and open-source software have become very valuable resources in the field of research and development, especially in satellite navigation. These receivers are highly valued for their adaptability and flexibility, allowing researchers to tailor the software to specific experimental needs or develop new signal processing algorithms. However, software-defined receivers tend to be less energy-efficient compared to hardware-based receivers, as they operate on general-purpose processors, which are not optimized for low power consumption.This thesis focuses on the design and development of a low-cost architecture for prototyping experimental GNSS receivers, based on System-on-Chip Field Programmable Gate Arrays (SoC FPGAs). This architecture overcomes the limitations of commercial GNSS receivers in terms of adaptability, flexibility, and reprogramming capacity, and offers improved energy efficiency compared to software-based receivers that rely on general-purpose processors. The strategy consists of combining the versatility of software-defined radio with the intensive parallelism and optimized energy consumption of programmable logic devices, providing the best of both worlds. This fusion allows the development of compact, portable GNSS receivers, thus facilitating the prototyping of embedded devices suitable for field testing. In addition, the GNSS processing core is based on a free and open-source software implementation, which provides detailed access to the signal processing chain and allows unrestricted exploration and modification of the algorithms used.This thesis also presents a design methodology for the development of new prototypes and new GNSS signal processing algorithms based on the proposed SoC FPGA architecture. This methodology places special emphasis on code reuse, a key aspect for reducing development costs and time.The practical applications of this architecture have been demonstrated through three prototypes: a GNSS receiver for low Earth orbit (LEO), a GNSS signal repeater, and a high-sensitivity GNSS receiver.The innovative approach presented in this thesis facilitates the development of experimental prototypes of flexible and portable GNSS receivers and signal generators, suitable for both laboratory experiments and field testing.