Doctoral School

Reading date: 19/04/2024

• ARNAIZ MARTÍNEZ, DAVID MARIANO: Bringing Self-Awareness to the Extreme Edge - A Distributed Approach for Adaptive Energy Management in WSNs Applied to Structural Health Monitoring
  
  Author: ARNAIZ MARTÍNEZ, DAVID MARIANO
  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: 21/03/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: ALARCON COT, EDUARDO JOSE | MOLL ECHETO, FRANCESC DE BORJA | VILAJOSANA GUILLEN, XAVIER
  Committee:
       PRESIDENT: CHOWDHURY, KAUSHIK ROY
       SECRETARI: ABADAL CAVALLÉ, SERGI
       VOCAL: DINI, PAOLO
  Thesis abstract: In today's landscape, data are increasingly becoming an invaluable resource to enhance decision-making, enable predictive insights, improving operational efficiency, among numerous other applications. Within the current data-centric mindset, wireless sensors play a facilitator role, allowing the collection of data in a flexible, low-cost, and simple-to-deploy way.One of the ever-pending challenges of wireless sensor node technologies is their limited energy availability, particularly their limited battery life. To extend their battery life, sensor nodes need to use their energy as frugally as possible. The optimal behavior for a sensor node is highly dependent on the varying operation conditions. Thus, to operate optimally, sensor nodes need to incorporate adaptive mechanisms to dynamically adjust their behavior at runtime. These adaptive mechanisms are commonly referred to as Dynamic Energy Management (DEM).Despite the progress made in DEM, commercial sensor nodes continue to mostly operate using static behaviors, wasting energy. The main limitation impeding the widespread adoption of DEM is that it renders the node's behavior dependent on the operating conditions, thereby making the node's behavior unpredictable. In recent years, self-awareness has been proposed as a promising solution to this challenge. Self-aware systems autonomously adjust their behavior at runtime based on their internal and external operating conditions to achieve their operational goals as efficiently as possible. Consequently, while the behavior of a self-aware system may not be known at a given time, these systems provide some level of predictability by complying with their operational goals.This thesis delves into the use of self-awareness at the sensor node level to guide the node's adaptive behavior. The main objective of this thesis is to provide a solid foundation to support future progress in self-aware sensor nodes. In pursuit of this goal, it presents a reference architecture of a self-aware sensor node solving the existing lack of standardization in their design. Additionally, it proposes two self-aware monitoring methods enabling the node to comply with its battery lifetime target while optimizing its energy allocation to maximize its monitoring accuracy. Another key aspect that limits the adoption of self-awareness at the sensor node level is the node's lack of information and computing capabilities to model complex environments, as is usually the case in Structural Health Monitoring (SHM) applications. This thesis tackles this issue by proposing an anomaly-aware monitoring method tailored for SHM applications, which models the local vibration patterns measured by the node to determine the current monitoring requirements for the node. Finally, the thesis ends by exploring how the concept of self-awareness can be extended through the network, enabling the interaction between self-aware sensor nodes and a self-managing monitoring application running in the cloud.
  

• FAKHRAEI, JAVAD: Contributions to meshless methodologies for the simulation of acoustic radiation and scattering problems
  
  Author: FAKHRAEI, JAVAD
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Mechanical Engineering (EM)
  Mode: Normal
  Deposit date: 16/02/2024
  Reading date: 19/04/2024
  Reading time: 11:30
  Reading place: Sala de conferències del TR5 de l'ESEIAAT (Terrassa)
  Thesis director: ARCOS VILLAMARÍN, ROBERT | PÀMIES GÓMEZ, TERESA
  Committee:
       PRESIDENT: CORTESÃO GODINHO, LUIS MANUEL
       SECRETARI: CLOT RAZQUIN, ARNAU
       VOCAL: DENIA GUZMÁN, FRANCISCO DAVID
  Thesis abstract: Meshless methodologies have emerged as a valuable tool in the field of computational acoustics, offering an efficientapproach to model complex acoustic phenomena. These innovative numerical techniques offer a promising alternative totraditional mesh-based methods to deal with scattering and radiation acoustic wave propagation problems. Unlikeconventional mesh-based approaches, meshless methods do not rely on structured grids of the domain or its boundary,enabling more flexible and adaptive discretisation. The absence of a mesh eliminates the need for time-consuming gridgeneration and refinement, simplifying the simulation process and reducing the computational effort. This efficiency isespecially valuable in addressing large-scale acoustic simulations, such as those encountered in environmental noiseassessments and underwater acoustics.This dissertation is particularly centred on the study and development of a novel group of numerical meshless methodsrelated to boundary collocation approaches. These methods are employed to address problems involving the propagation ofacoustic waves in unbounded domains. The novel approaches presented in this research offer several benefits with respectto existing methodologies, in terms of robustness, accuracy and computational efficiency. Furthermore, in contrast to a fullythree-dimensional analysis, the approaches presented in this dissertation are formulated in the two-and-a-half-dimensionaldomain. This domain is particularly suited for scenarios where the system is subjected to longitudinally moving loads orsources and where the geometry of the system remains longitudinally invariant.The meshless methodologies developed in this thesis mainly rely on two of the most well-established meshless methods inthe field: the singular boundary method and the method of fundamental solutions. In the first instance, an approach based ona two-and-a-half-dimensional version of the singular boundary method is proposed and studied to address acousticradiation and scattering problems. Subsequently, its applicability for real case acoustic scenarios is evaluated throughsimulations involving point source diffraction in the presence of thin noise barriers. As probably representing the mostsignificant novelty of this dissertation, a hybrid method that combines the singular boundary method and the method offundamental solutions is introduced. It is specifically devised to tackle acoustic wave propagation problems featuringcomplex boundary geometries with corners and sharp edges. Finally, two modification techniques are proposed to enhancethe previously mentioned approach based on the two-and-a-half-dimensional sin- gular boundary method. The Burton¿Millerformulation in a first instance, and a dual surface scheme in the second. These modifications aim to overcome the issue ofspurious eigensolutions, which arises from the non-uniqueness solution problem associated with boundary collocationmethods. To comprehensively assess the capabilities and performance of the proposed meshless methods, the availableanalytical solutions and alternative numerical strategies such as the well-known boundary element method are also utilisedin various designed benchmark problems.
  

• PRAT ORTELLS, JAUME: Espai núvol: una anàlisi de l¿arquitectura de RCR arquitectes a través de les seves atmosferes.
  
  Author: PRAT ORTELLS, JAUME
  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 DESIGN
  Department: Department of Architectural Design (PA)
  Mode: Normal
  Deposit date: 07/02/2024
  Reading date: 19/04/2024
  Reading time: 11:00
  Reading place: Presencial Sala de Graus ETSAB. Planta Baixa
  Thesis director: COLL LOPEZ, JAIME | MASIP BOSCH, ENRIC
  Committee:
       PRESIDENT: BATLLE DURANY, ENRIC
       SECRETARI: CALLÍS FREIXAS, EDUARD
       VOCAL: LACASTA CODORNIU, MIGUEL
       VOCAL: BAILO ESTEVE, MANUEL
       VOCAL: PRIETO GONZÁLEZ, NURIA
  Thesis abstract: The work of RCR arquitectes is recognizable and recognized, based on intense interventions almost always represented from the inside out, deep, somber, which often incorporate this outside, this environment, in their expression: works, therefore, woven through their relationships with this environment, with the inhabitants, works that define deep spaces, gradations through architectural elements converted into filter systems; more an environment, a scene, an atmosphere, than an object. This atmospheric consideration is the basis of the understanding of the work of this study proposed by this thesis, and it does so through a journey through three scales of relationship between the work of architecture and its environment -with the atmosphere they generate- through a project associated with each of these stairs: The Entremurs House by the relationship scale of the person, the Espai La Lira for the city, the Pavelló del Baño -the smallest- for the territory. The analysis of the projects -carried out through a consultation of the original documentation deposited in the studio archives, much of it unpublished-, their relationship both with their own architecture and with many others, and an interpretation of each of these projects -all accompanied by a revisit of each of them- will allow us to introduce ourselves to the logic of the work of RCR arquitectes until we can question ourselves about a possible definition of the spaces proposed by this Study in this atmospheric key.
  

Reading date: 22/04/2024

• AZIZIAN, POOYA: MICROFLUIDICS FOR BIOSENSING WITH ADDITIVE MANUFACTURING:SIMULATION MODEL AND FABRICATION
  
  Author: AZIZIAN, POOYA
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Mechanical Engineering (EM)
  Mode: Article-based thesis
  Deposit date: 26/03/2024
  Reading date: 22/04/2024
  Reading time: 09:00
  Reading place: Sala de Conferències del TR1 de Campus UPC Terrassa.
  Thesis director: CASALS TERRE, JASMINA | CABOT CANYELLES, JOAN MARC | ORTEGA NOVILLO, ADRIAN | RICART CAMPOS, JORDI
  Committee:
       PRESIDENT: BENITO LÓPEZ, FERNANDO
       SECRETARI: RODRÍGUEZ VILLARREAL, ÁNGELES IVÓN
       VOCAL: BORTOLOTTI, CARLO AUGUSTO
  Thesis abstract: Over the last decade, biosensing has been moving towards the miniaturized and cost-effective point-of-care (POC) testing. Even though microfluidics is becoming a key enabling technology for POC testing, the need for robust peripheral equipment has been a notable limiting factor in extending its prevalence. By manipulating microchannels' geometry and surface properties, capillary-driven microfluidics can control fluids spontaneously, reducing the need for external instrumentation. This advantage is becoming more accessible, considering that additive manufacturing technologies are reaching a high level of maturity that allows cost-effective and rapid fabrication of three-dimensional (3D) features down to the sub-millimeter scale. Therefore, capillary-driven microfluidics are achieving higher technological readiness.A key component within the field of capillary-driven microfluidics is the capillary valve. The capillary valve can automatically stop and actuate fluid flows depending on the molecular interactions between the liquid and the microchannel surfaces. However, a major concern for these valves is the presence of unwanted diffusion and mixing during the valve function, leading to cross-contamination between reagents or even with the sample. This thesis studied different methods in the literature to stop and actuate the flow as the two main stages of these valves. Then, passing over the state-of-the-art, a novel 3D diffusion-free capillary valve was developed: the ¿-valve. This valve incorporates an air gap between solutions to eliminate diffusion between them. Based on the valve's distinctive configuration, the capillarity of the microfluidic circuit displaces the air gap at a predefined time to actuate without producing bubbles into the circuit. The proposed valve's design and study were performed via numerical simulation and experimental assays, while 3D printing (3DP) was employed to fabricate the microfluidic devices.The ¿-valve's functionality, single and in array, was proven and compared with the conventional capillary valves. Then, it was applied to the precise control of reagents for biosensing, demonstrated by two different competitive immunoassays via (i) the subsequent washing step for the lateral flow assay of cortisol, and (ii) the valve array for the sequential delivery of sample and three reagents to detect benzodiazepine quantitatively. The sensitivity was enhanced by avoiding the reagent diffusive premixing when using the ¿-valve by approximately 40%. As a result, the proposed capillary valve is a promising capillary component for conducting automated immunoassays at POC.In conclusion, the novel capillary valve addresses a current biosensing sensitivity issue coming from reagent diffusive premixing, and together with other disruptive capillary-driven circuit components, paves the way for truly packing lab-on-a-chip without requiring a lab around the chip. In this regard, the next generation of capillary-driven microfluidic devices will be promising tools offering (i) miniaturized features needing fewer samples and reagents, (ii) non-costly POC testing without peripheral instrumentation, (iii) automated, preprogrammed, and easy-to-use for non-expert users, as well as (iv) sensitive, precise and reliable based on novel 3D designs employing surface properties. This is owing to the recent advancements in microfabrication based on additive manufacturing extending 3D forming freedom.
  

• RIVET FERNÁNDEZ, IVÁN: Computational Multiscale Analysis for Additive Manufacturing
  
  Author: RIVET FERNÁNDEZ, IVÁN
  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: (DECA)
  Mode: Article-based thesis
  Deposit date: 18/03/2024
  Reading date: 22/04/2024
  Reading time: 11:00
  Reading place: Sala de Seminarios O.C. Zienkiewicz del Centro Internacional de Métodos Numéricos en Ingeniería - CIMNE Campus Nord de la UPC, Edifici C1 - 2a Planta, 08034 Barcelona
  Thesis director: CERVERA RUIZ, LUIS MIGUEL | DIALAMI SHABANKAREH, NARGES
  Committee:
       PRESIDENT: AURICCHIO, FERDINANDO
       SECRETARI: CAICEDO SILVA, MANUEL ALEJANDRO
       VOCAL: DOMINGO-ESPIN, MIQUEL
  Thesis abstract: This thesis aims towards the understanding and optimization of Additive Manufacturing (AM) components through the application of accurate computational multiscale simulations. The research is guided by three primary objectives: (1) the development of a multiscale orthotropic material model tailored for Fused Filament Fabrication (FFF) components, (2) the formulation of an optimization strategy to enhance the mechanical performance of FFF parts, and (3) the comprehensive characterization and modeling of their failure mechanisms.To address the first objective, a printing pattern-based orthotropic material model in the framework of multiscale analysis is constructed. This model accounts for the intricate interactions occurring at both filament and component scales in FFF, offering a nuanced representation of the material's behavior. By bridging these scales, the model ensures a comprehensive understanding of the mechanical response of FFF parts, enabling accurate predictions of their performance and failure modes.The second objective focuses on the optimization of the mechanical performance of FFF components. Leveraging the developed multiscale material model, an optimization strategy based on a novel statistics-based algorithm and an orthotropic failure criterion is formulated. The computational domain generation strategy is also tackled, analyzing different approaches and taking advantage of an Adaptive Mesh Refinement (AMR) technique to reduce the computational cost of the simulations. The developed methodology is fully embedded into the AM workflow.The final objective involves the characterization and modeling of the different failure mechanisms present in FFF parts. The different failure modes exhibited by FFF components are identified for each printing pattern present in the component, and a Mechanism-Based (MB) damage criterion is developed to model their stiffness degradation. In addition, an MB cracking model that accounts for the orthotropic brittleness of FFF parts is presented and validated against experimental tests.The central motivation driving this thesis is to alleviate the dependency on costly experimental procedures for characterizing and/or predicting the mechanical behavior of FFF components by performing high-precision and inexpensive multiscale simulations. The outcomes of this study aim to improve the current Design for Additive Manufacturing (DfAM) guidelines.