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Theses authorised for defence

DOCTORAL DEGREE IN APPLIED MATHEMATICS

  • ROCA LACOSTENA, JORDI: The embedding problem for Markov matrices
    Author: ROCA LACOSTENA, JORDI
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN APPLIED MATHEMATICS
    Department: School of Mathematics and Statistics (FME)
    Mode: Normal
    Deposit date: 16/04/2021
    Reading date: 18/05/2021
    Reading time: 09:00
    Reading place: Facultat de matemàtiques i Estadística - UPC Campus Sud - Videoconferència : meet.google.com/qks-uyrm-gby
    Thesis director: FERNANDEZ SANCHEZ, JESUS | CASANELLAS RIUS, MARTA
    Committee:
         PRESIDENT: SUMNER, JEREMY
         SECRETARI: SERRA ALBO, ORIOL
         VOCAL: KUBJAS, KAIE
    Thesis abstract: The goal of this thesis is to solve the embedding problem for Markov matrices, posed by Gustav Elfving in1937. A Markov matrix is non-negative square matrix whose rows sum to 1. We say that such a matrix M is embeddable if it can be written as the exponential of a rate matrix, that is a real square matrix with rows summing to zero and non-negative off-diagonal entries. In this case, we say that the rate matrix is a Markov generator for M. The embedding problem consists deciding whether a given Markov matrix is embeddable or not, thus solving the embedding problem results in giving a characterization of embeddablem matrices.This problem is motivated by Markov processes, which are used to model the change of state of a random variable over time. under the assumption that future is independent from past given the present, that is, the assumption that the substitution probabilities do not depend on previous changes of state. In this framework, the entries of Markov matrices represent the substitution probabilities along a fixed time interval. When these probabilities ar considered to be continuous (and differentiable) functions depending on time, the Markov process is ruled by the instantaneous rates of substitution between states. In order to keep continuous-time Markov processes tractable, the substitution rates are usually assumed to be constant over time. In this case, we say that the process is a homogeneous continuous-time process and one displays all the rates together in a matrix called rate matrix Q. Moreover, the Markov matrix encoding the substitution probabilities after time t can be written as M(t) = exp(Qt) for all t=0. Thus, M(t) is embeddable and Qt is a Markov generator for it. Therefore, in the context of substitution processes, the embedding problem consists on deciding whether a given transicion matrix can be obtained from a homogeneous Markov process in continuous-time.The embedding problem is solved for 2x2 and 3x3 Markov matrices and also for some particular cases such as matrices close to the identity or matrices with dferent real eigenvaleus. In this thesis we present a method to decide wheter a Markov matrix with different eigenvalues (real or not) is embeddable. This solves the embedding problem for a dense subset of nxn Markov matrices for any size n. We also study the rate identifiability problem, which is concerned about the unicity of Markov generators for a given embeddable matrix. Moreover, we give an explicit solution for the embedding problem for 4x4 Markov matrices. Not only this case was the smaller unsolved case, but it has practical consequences in phylogenetics as the embedding problem appears related to fundamental questions concerning the consistency of nucleotide substitution models. These models generally use a Markov process to describe the substitution of nucleotides over time in a given DNA sequence. We give the solution of the embedding problem restricted to some commonly used nucleotide substitution models such as Kimura models and the strand-symmetric model. For each of these models, one can define two different versions related by the embedding problem, a homogeneous continuous-time version and a more general version that avoids the time consideration. We shall see that the proportion of embeddale matrices (i.e. in the continuous-time version of the model) within the general version of the model decreases as the model hypothesis are relaxed. Indeed, we shall see that the proportion of embeddable matrix lies in the range between the 0.05% and the 75% depending on the complexity of the model. This shows that the time-continuous versions of these models are much more restrictive.

DOCTORAL DEGREE IN ARCHITECTURAL, BUILDING CONSTRUCTION AND URBANISM TECHNOLOGY

  • MIRBAGHERI, MAHSA: Urban cemetery biophilic integration for human well-being (An applied case study of Tehran, Iran)
    Author: MIRBAGHERI, MAHSA
    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: Normal
    Deposit date: 25/03/2021
    Reading date: 25/05/2021
    Reading time: 16:00
    Reading place: Sala de Graus ETSAB - UPC Campus Sud - Av Diagonal 649, 08028 Barcelona - videoconferència: meet.google.com/jzn-kpju-guo
    Thesis director: PARDAL MARCH, CRISTINA | ROCA BLANCH, ESTANISLAO
    Committee:
         PRESIDENT: GARCÍA VÁZQUEZ, CARLOS
         SECRETARI: MARTI CASANOVAS, MIQUEL
         VOCAL NO PRESENCIAL: DOS SANTOS FERREIRA DA FONSECA BENTO, PEDRO JOSÉ
    Thesis abstract: Cemeteries are an ancient reality, and while their basic function has not changed, their physical layout as well as the symbolic and emotional role within our societies has undergone profound transformations over time. The Oxford dictionary literally defines cemetery as ¿A large burial ground¿. The meaning in the American heritage dictionary is similar: ¿A place for burying the dead.¿ The definitions of cemetery in both dictionaries significantly mentions the dead and dark side of these spaces. Not only these definitions but also modern zoning legislation on cemeteries deny their role as urban open public green spaces and their potential to contribute to human well-being. Decisions about cemeteries segregation follow two-dimensional land-use urban planning, without considering their relationships with other urban spaces and without a real understanding of human behavior. The usual process of urban development treats cemeteries as isolated singular function urban spaces, not as part of larger urban fabrics. This vision leads to the appearance of urban spaces without any urban design qualities. This research was conceived to investigate the main process of urban cemeteries integration with cities and human daily life by biophilic approaches (based on Iran as a case study). It has the potential to make an important contribution to both academic research and planning decisions on the roles of urban cemeteries in cities and their response to human well-being. The thesis is based on two literature review parts concerning urban design assessment and biophilic applied methods. It highlights the necessity of intervention at different scales (urban planning, urban design, architecture, and landscape design) in order to develop an integration process of cemeteries. The case study of Tehran and references to international cases lead to address the general strategies and guides of this process in detail.

DOCTORAL DEGREE IN AUTOMATIC CONTROL, ROBOTICS AND VISION

  • GARCIA LOPEZ, JAVIER: Geometric computer vision meets Deep Learning for autonomous driving applications
    Author: GARCIA LOPEZ, JAVIER
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN AUTOMATIC CONTROL, ROBOTICS AND VISION
    Department: Institute of Robotics and Industrial Informatics (IRI)
    Mode: Temporary seizure
    Deposit date: 05/03/2021
    Reading date: 17/05/2021
    Reading time: 10:00
    Reading place: Aula capella ETSEIB_ Defensa per videoconferència https://meet.google.com/ccy-mcrz-ufs
    Thesis director: MORENO NOGUER, FRANCESC D'ASSIS | AGUDO MARTÍNEZ, ANTONIO
    Committee:
         PRESIDENT: VENTURA ROYO, CARLES
         SECRETARI: SÁNCHEZ RIERA, JORDI
         VOCAL: HERRANZ ARRIBAS, LUIS
    Thesis abstract: This dissertation intends to provide theoretical and practical contributions on the development of deep learning algorithms forautonomous driving applications. The research is motivated by the need of deep neural networks (DNNs) to get a fullunderstanding of the surrounding area and to be executed on real driving scenarios with real vehicles equipped with specifichardware, such as memory constrained (DSP or GPU platforms) or multiple optical sensors, which constraints the algorithm'sdevelopment forcing the designed deep networks to be accurate, with minimum number of operations and low memoryconsumption.The main objective of this thesis is, on one hand, the research in the actual limitations of DL-based algorithms that prevent themof being integrated in nowadays' ADAS (Autonomous Driving System) functionalities, and on the other hand, the design andimplementation of deep learning algorithms able to overcome such constraints to be applied on real autonomous drivingscenarios, enabling their integration in low memory hardware platforms and avoiding sensor redundancy. Deep learning (DL)applications have been widely exploited over the last years but have some weak points that need to be faced and overcame inorder to fully integrate DL into the development process of big manufacturers or automotive companies, like the time needed todesign, train and validate and optimal network for a specific application or the vast knowledge from the required experts to tunehyperparameters of predefined networks in order to make them executable in the target platform and to obtain the biggestadvantage of the hardware resources. During this thesis, we have addressed these topics and focused on the implementationsof breakthroughs that would help in the industrial integration of DL-based applications in the automobile industry.This work has been done as part of the "Doctorat Industrial" program, at the company FICOSA ADAS, and it is because of thepossibilities that developing this research at the company's facilities have brought to the author, that a direct impact of theachieved algorithms could be tested on real scenarios to proof their validity. Moreover, in this work, the author investigates deepin the automatic design of deep neural networks (DNN) based on state-of-the-art deep learning frameworks like NAS (neuralarchitecture search). As stated in this work, one of the identified barriers of deep learning technology in nowadays automobilecompanies is the difficulty of developing light and accurate networks that could be integrated in small system on chips (SoC) orDSP. To overcome this constraint, the author proposes a framework named E-DNAS for the automatic design, training andvalidation of deep neural networks to perform image classification tasks and run on resource-limited hardware platforms. Thisapporach have been validated on a real system on chip by the company Texas Instrumets (tda2x) provided by the company,whose results are published within this thesis. As an extension of the mentioned E-DNAS, in the last chapter of this work theauthor presents a framework based on NAS valid for detecting objects whose main contribution is a learnable and fast way offinding object proposals on images that, on a second step, will be classified into one of the labeled classes.

DOCTORAL DEGREE IN CHEMICAL PROCESS ENGINEERING

  • BINTI SHAARANI, FARRA WAHIDA: Synthesis and Characterization of Polycarbonates from Epoxidized Vegetable Oils, Propylene Oxide and Carbon Dioxide
    Author: BINTI SHAARANI, FARRA WAHIDA
    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: 29/03/2021
    Reading date: 20/05/2021
    Reading time: 10:00
    Reading place: (16 pm Malàisia )- ETSEIB: Defensa per videoconferència per COVID19 https://meet.google.com/mos-mozn-pns
    Thesis director: BOU SERRA, JORGE
    Committee:
         PRESIDENT: MASDEU I BULTÓ, ANNA MARIA
         SECRETARI: ALMAJANO PABLOS, MARIA PILAR
         VOCAL: SHARIFFUDDIN, JUN HASLINDA
    Thesis abstract: The current research is primarily focused on the preparation of a polycarbonate using epoxidized linseed oil (ELO) and epoxidized soybean oil (ESO) as feedstocks. The presence of unsaturation in vegetable oil structure enables chemical modifications to introduce epoxy group which further used to synthesize polycarbonate via catalytic copolymerization with carbon dioxide (CO2). In this study, with the presence of heterogeneous catalyst a mixture of epoxidized vegetable oil and propylene oxide (PO) were reacted with CO2. Synthesis of polycarbonate via this pathway helps to lessen the reliance on petroleum-based feedstocks and besides employing renewable raw materials meets the 7th principle of 12 Principles of Green Chemistry that contributes to sustainability in chemistry.The research work is divided into four phases. The first phase comprises preliminary studies whereby preparation of a heterogeneous catalyst for the copolymerization of epoxide with CO2 were made. Catalyst screening tests showed that cobalt- zinc double metal cyanide (Co-Zn DMC), a heterogenous catalyst commonly employed in the copolymerization reaction was feasible for cyclohexene oxide (CHO)/CO2 and PO/CO2 copolymerization. Then in-situ epoxidation of unsaturated fatty acids using selected vegetable oils were carried out to modify vegetable oil to epoxidized vegetable oil. The molar ratio of 0.4:0.1:1.7 (organic acid: double bonds: hydrogen peroxide) were applied and the epoxidation reaction took place at 70ºC for five hours. No formation of polymer was observed from the terpolymerization of epoxidized olive oil (EOO), epoxidized palm oil (EPO) and epoxidized sunflower oil (ESFO) most likely due to the low content of epoxy group of the epoxide oils used. However, from the preliminary studies a promising result were obtained from both ELO and ESO whereby a polymer has been successfully developed from the copolymerization reaction.The second phase of the work is focused on the copolymerization of ESO, PO and CO2 catalyzed by Co-Zn DMC. Products comprises of mixture of poly(propylene carbonate), cyclic carbonate and polyether unit. The Mn of the polymeric products recorded is 6498 g. mol-1 with the percentage incorporation of ESO in the polymer is only 7.8%.The third phase of the work is dedicated on the development of a poly(carbonate-co-ether) using ELO as the starting material. The terpolymerization reaction were conducted at fixed CO2 pressure of 5 MPa and various catalyst loading, reaction temperature and reaction time. At CO2 pressure of 5 MPa, reaction temperature of 60ºC, reaction time of 24 h and catalyst loading of 0.2 g, the resultant polymer with maximum Mn of 6.21 x 105 g.mol-1 and PDI of 1.05 was recorded.Finally, the ability of the synthesized polymer to degrade was study under aerobic condition. The aerobic biodegradation of the test materials was determined under controlled composting conditions by analysis of evolved CO2 using an in-house built direct measurement respirometric (DMR) system. Results from this study discloses that 44.6% of PC-ELO and 51.8% of PC-ESO were degraded at the end of trial period. Both polymers were able to degrade most likely due to the co-monomer employed in the copolymerization reaction are renewable and bio based.
  • CORRUCHAGA GUERRERO, AGUSTÍN: Estudio de la evaporación de vertidos de disoluciones acuosas de amoníaco
    Author: CORRUCHAGA GUERRERO, AGUSTÍN
    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: Temporary seizure
    Deposit date: 26/03/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: CASAL FABREGA, JOAQUIM | PALACIOS ROSAS, ADRIANA
    Committee:
         PRESIDENT: MUTJÉ PUJOL, PERE
         SECRETARI: PLANAS CUCHI, EULALIA
         VOCAL: ZÁRATE LÓPEZ, LUIS GUADALUPE
    Thesis abstract: Evaporation from liquid spills is a phenomenon of great importance. This phenomenon has been studied by a number of researchers. However, most of them have focused on the evaporation of pure liquid spills or hydrocarbon mixtures, very few have analyzed the evaporation of ammonia from aqueous solutions.The work described in this thesis aims to be a contribution to the knowledge and prediction of the main FEATURES of ammonia evaporation from discharges of aqueous solutions.The first chapter briefly describes the main products derived from ammonia, as well as an overview of the evolution of production figures for this substance. The main characteristics in terms of transport and storage are also mentioned. Finally, the risks associated with the production and transport of ammonia are exposed.The second chapter presents a review of the most significant publications and of the different models proposed by various authors for the prediction of the evaporation rate, both from a generic point of view and in the specific, much smaller, case of the ammonia solutions.The third chapter is dedicated to the historical analysis of accidents that occurred in industrial facilities or in transport in which ammonia has been implicated. The results obtained from the statistical treatment of the information extracted from the different databases consulted are presented, dedicating a special section to transport by pipeline, given its importance. Finally, a major accident that occurred in Kingman (Kansas) in 2004 is described and analyzed.The fourth chapter describes the experimental set-up designed and built to obtain experimental data on the evaporation of ammonia from aqueous solutions under the influence of an air current.The fifth chapter presents the experimental data related to the evolution of temperature, concentration and mass, during the evaporation process of ammonia solutions at different air speeds.Finally, in the sixth chapter the modeling of the phenomenon is presented. In the first place, the three consecutive phases that have been observed throughout the process are described when analyzing the evolution of the mass and the temperature of the solution. Their existence may be important from the point of view of analyzing the risk associated with the possible generation of a toxic cloud in the case of an accidental spill, given the high evaporation rate in the first phase, and from the point of view of view of emergency management. To illustrate this aspect, it has been calculated with the ALOHA (Areal Locations of Hazardous Atmospheres) software, the leeward area in which there could be an impact on people for a given spill. These values highlight the hazard that an accidental spill could imply for people in the affected area. The experimental data have also been correlated with the most suitable dimensionless groups through dimensional analysis. This has made it possible to obtain a new expression to estimate the mass transfer coefficient (k) and to modify the equation frequently used to determine the evaporation rate. Likewise, the term relative to the equivalent diameter of the discharge has been deleted, since its inclusion in the model does not make sense for full-scale discharge. It has been studied how an increase in air speed produces an increase in evaporation speed, and how this influence is reduced as air speed increases. Finally, a comparison between the experimental data and those calculated with the new model is presented.

DOCTORAL DEGREE IN COMPUTATIONAL AND APPLIED PHYSICS

  • CASTRILLON CAMACHO, ARJUNA: Estudio de las propiedades fisicas en regiones chocadas en nebulosas planetarias.
    Author: CASTRILLON CAMACHO, ARJUNA
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN COMPUTATIONAL AND APPLIED PHYSICS
    Department: Department of Physics (FIS)
    Mode: Normal
    Deposit date: 24/03/2021
    Reading date: 12/05/2021
    Reading time: 15:00
    Reading place: Facultat d'Informàtica de Barcelona - UPC Campus Nord - videoconferència: https://meet.google.com/arz-vxyb-iqy
    Thesis director: JOSE PONT, JORDI | GARCÍA SENZ, DOMINGO
    Committee:
         PRESIDENT: DOMINGUEZ AGUILERA, MARIA INMACULADA
         SECRETARI: SALA CLADELLAS, GLÒRIA
         VOCAL: TRIGO RODRIGUEZ, JOSEP MARIA
    Thesis abstract: Planetary nebulae play a very important role in the chemical evolution of galaxies since they are responsible for returning nuclear-processed material to the interstellar medium. Observations of planetary nebulae are used to determine the chemical abundances present in the interstellar medium and in all galaxies.In this study, the properties and characteristics of the small-scale structures present in planetary nebulae are analyzed. The aim of this work is to understand the evolutionary fate of low and intermediate mass stars. Specifically, this work focuses on the study of episodes known as "jets", which are ejected by the central star of the planetary nebula. The presence of collimated bipolar fluxes and point-symmetry morphologies are commonly observed in planetary nebulae, but the physics of such structures is not yet well understood. With this thesis we want to determine the observational properties of some structures present in planetary nebulae, known as FLIER's/LlS (Fast Low Ionization Emission Regions [FLIERsl and Low Ionization Structures [LIS]).In a first phase, the morphology of a sample of planetary nebulae selected from the HST (Hubble Space Telescope) database is analyzed by applying anisotropic wavelet analysis. Through this analysis, we determined: first, the spatial distribution of the structures of interest (FLIERs/LlS) and their characteristic sizes; second, spectroscopic data with two-dimensional coverage of our sample are obtained. With these data, we can draw maps of physical conditions, such as the excitation and the ionization structure in bow shocks. Through these maps we can show the effects of photoionization due to heating caused by the central star in the areas known as irradiated shocks.All the analyses carried out on the planetary nebulae considered in this work yield conclusive results on the presence of microstructures. The abrupt changes evidenced in the ratios studied (10 Ill]/Ha, [N Il]/Ha) are a clear indication of the presence of microstructures in the regions of irradiated shocks. From the wavelet analysis, the presence of "knots", "jets", "jet-like" and filaments is evidenced in each of the nebulae considered. Additionally, the one-dimensional profiles present a slight spatial shift in each of the spectral lines considered (10 Ill], [N Il], and Ha), which indicates that the structures are symmetrically located with respect to the central star.From the analysis of the protoplanetary nebula CR 618, the movements of the lobes measured in two different time periods are quantified. From this, the parameters of the simulation using the hydrodynamic code created by Raga (2000) are set. We obtained encouraging results in the study of this nebula, allowing us to give an explanation to the proper motions and the morphology of the lobes from the well-collimated bipolar ejection and the precession in the axis of their flow.

DOCTORAL DEGREE IN CONSTRUCTION ENGINEERING

  • PENG, TIAN: Structural System Identification by Dynamic Observability Technique.
    Author: PENG, TIAN
    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: 20/04/2021
    Reading date: 21/05/2021
    Reading time: 15:30
    Reading place: Escola de Camins, Edifici C1, Aula 002, Campus Nord
    Thesis director: TURMO CODERQUE, JOSE | CASAS RIUS, JUAN RAMON
    Committee:
         PRESIDENT: RAMOS SCHNEIDER, GONZALO
         SECRETARI: MARTINEZ RODRIGO, MARIA DOLORES
         VOCAL NO PRESENCIAL: YUAN, SUN
    Thesis abstract: Structure system identification (SSI) can be classified as static and dynamic depending on the type of excitation. SSI by Observability Method (OM) using static tests was proposed and analyzed to address the observability of the estimated parameters. This mathematical approach has been used in other fields such as hydraulics, electrical, and power networks or transportation. Usually, the structural behavior of engineering structures can be identified according to dynamic characteristics such as mode shapes, natural frequencies, and damping ratios. However, the analysis of SSI by dynamic Observability Method using dynamic information is lacking. This Ph.D. thesis developed the dynamic Observability Method using masses, modal frequencies, modal deflections based on the static OM to obtain the geometrical and mechanical parameters of the structure. This thesis mainly contains three aspects of work.Firstly, in chapter 3, the development, for the first time, of constrained observability techniques (COM) for parametric estimation of structures using dynamic information such as frequencies and mode-shapes was proposed. New algorithms are introduced based on the dynamic eigenvalue equation. Two step by step examples are used to illustrate the functioning of these. Parametric expressions for the observed variables are successfully obtained,which will allow the study of the sensitivity of each of the variables in the problem and the error distribution, which is an advantage with respect to non-parametric SSI techniques. A large structure is used to validate this new application, whose structural properties can be obtained satisfactorily in either the whole or local analysis, and the results show that the required measurement set is smaller than the required for a static analysis. Chapters 4 and 5 are the applications of COM to fill the shortcomings of current research, such as the optimal SHM+SSI strategy and uncertainty quantification.Secondly, in chapter 4, the role of the SHM strategy and the SSI analysis based on the Constrained Observability Method (COM), which aims at reducing the estimation error, is discussed. A machine learning decision tool to help building the best-combined strategy of SHM and SSI that can result in the most accurate estimations of the structural properties is proposed, and the combination of COM and decision tree algorithm is used for the first time. The machine learning algorithm is based on the theory of Decision Trees. Decision trees are firstly presented to investigate the influence of the variables (layout of bridge, span length, measurement set, and weight factor in the objective function of the COM) involved in the SHM+SSI process on the error estimation in a general structure. The verification of the method with a real bridge with different levels of damage shows that the method is robust even for a high damage level, showing the SHM+SSI strategy that yields the most accurate estimation.Finally, an analysis of uncertainty quantification (UQ) is necessary to assess the effect of uncertainties on the estimated parameters and to provide a way to evaluate these uncertainties. This work is carried out in chapter 5. There are a large number of UQ approaches in science and engineering. It is identified that the proposed dynamic Constrained Observability Method (COM) can make up for some of the shortcomings of existing methods. After that, the COM is used to analyze a real bridge. A result is compared with a method based on a Bayesian approach demonstrating its applicability and correct performance through the analysis of a reinforced concrete beam.

DOCTORAL DEGREE IN EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS

  • AVILA HARO, JORGE ARTURO: Análisis estructural probabilista orientado a evaluación del daño sísmico de edificios de mampostería no reforzada: aplicación a edificios aislados y agregados del distrito del ensanche de Barcelona.
    Author: AVILA HARO, JORGE ARTURO
    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 EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS
    Department: (DECA)
    Mode: Normal
    Deposit date: 22/04/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: GONZALEZ DRIGO, JOSE RAMON | BARBAT BARBAT, HORIA ALEJANDRO | PUJADES BENEIT, LUIS GONZAGA
    Committee:
         PRESIDENT: GOULA SURIÑACH, XAVIER
         SECRETARI: LANTADA ZARZOSA, MARIA DE LAS NIEVES
         VOCAL NO PRESENCIAL: FOTI, DORA
    Thesis abstract: Despite the fact that masonry is one of the oldest and most used building materials, the number of existing studies and experimental data, as well as the applicability of its results (i.e. extrapolation), are substantially lower than those available for much more recent materials, such as concrete or steel. Furthermore, currently in Europe, a large number of residential buildings belong to masonry typologies. These circumstances justify the study of the characteristics and behaviour of the masonry to guide studies on seismic vulnerability.In particular, the Eixample district of Barcelona, in Spain, presents an urban park of functional housing made up 73% of unreinforced masonry structures, solved by means of load-bearing wall systems, without any consideration of seismic action and that, for the most part, exceed 100 years of useful life. These buildings, characteristics of Barcelona, have elements that differentiate them from other buildings of the same construction typology that can be found in other regions of Europe: 1) the number of floors significantly exceeds the average, being able to find buildings with up to 10 or 11 levels; 2) The buildings share dividing walls (e.g. lateral), thereby generating frameworks of buildings known as aggregates; 3) The properties and qualities of the different construction elements are closely linked to the production processes, not yet mechanized, of the time; 4) The level of construction techniques and the qualification of the workforce were very high.In this work, numerical 3D models of isolated structural configurations (i.e. individual building) and in aggregate, of existing buildings have been made, in order to determine and compare the behaviour between the different structural configurations. The buildings have been modelled incorporating the variability of their mechanical parameters and the seismic demand has also been selected taking into account its uncertainty.The structural analysis has been carried out using and comparing different non-linear static calculation procedures and using the incremental non-linear dynamic analysis as a reference. A discussion was carried out comparing the results and the degree of reliability of the different procedures used in relation to the typology of unreinforced masonry buildings. It can be concluded that the simplified methods (i.e. non-linear static) overestimate the damage corresponding to low values of PGA and underestimate the damage for higher values of PGA. Using different criteria, and including the probabilistic consideration of mechanical properties, as well as seismic demand, the foreseeable damage for these structures has been characterized by fragility functions and matrices and damage indices. A study of the correlation between the mechanical parameters and the observed damage is also provided, from which, a high correlation between the obtained results and the variables of interest, is observed, being the Young¿s modulus, E, the variable with the highest correlation coefficients.The common difficulties, in any work that involves large samples in relation to the amount of resources and computing time, have been solved through the design of adequate and sufficiently representative samples and by using current computational methods and tools, such as parallel and distributed computing.
  • MONTALBAN TURON, CARLOS: Análisis estructural de escaleras para edificios frente a viento y sismo
    Author: MONTALBAN TURON, CARLOS
    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 EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS
    Department: (DECA)
    Mode: Normal
    Deposit date: 14/01/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: BRUFAU NIUBÓ, ROBERTO | GONZALEZ DRIGO, JOSE RAMON
    Committee:
         PRESIDENT: MAÑA REIXACH, FRUCTUOSO
         SECRETARI: MARTÍN SÁIZ, RODRIGO
         VOCAL: DE SOUSA CRUZ, PAULO JORGE
    Thesis abstract: In this PhD Dissertation the structural performance of buildings with stairs submitted to lateral loads, is investigated. Because of the historical neglect of the interaction effects between the main structure and stairs, in professional and scientific practices, the objective is to address the current uncertainty regarding the structural safety of the evacuation exits of buildings, when they face seismic threats. For this reason, solutions are investigated in search of the optimal interaction between the main structure and the stairs. Currently, the project of buildings with stairs is controlled by different types of regulations, to ensure that, in an accidental situation, the stairs are the safest place and route to evacuate the building. However, in front of seismic threats, it is recommended not to stay in areas of the building with stairs, because it has been proven that they are elements highly vulnerable to the effects of the earthquake. The criteria for fire safety and against seismic threats are contradictory. Therefore, the need to rethink the way of designing stairs as well as their interaction with the building structure is confirmed. In an accidental situation (be it due to fire or to earthquake), the integrity of the staircase is essential to ensure a rapid evacuation of and adequate assistance to the users of the building and, for this reason, the structural safety of the evacuation routes should be guaranteed, in front of any accidental situation. In this research, four three dimensions (3D) models have been defined and, in each one of them, a non-linear static analysis has been performed against incremental pushes in the two main directions, which involves eight pushover analyses. Two analysis models correspond to the usual way of analyzing seismic behavior today, that is, without considering the structural presence of the stairs in the calculation model. The other two propose two different stair solutions, which, in these cases, have been modeled as part of the main structure. The research is carried out through three different fields of knowledge, the coordination of which has made it possible to solve a problem of international concern that each year causes the loss of hundreds of humans¿ lives, serious accidents and significant material damage, on all continents of the world. The three main areas of knowledge are: 1) architecture, 2) steel building engineer-ing, and 3) the study of seismic behavior (earthquake engineering). The contribution of this thesis to the problem of the fragility of the stairs could hardly have been made from the specialization in a single area of the three mentioned ones. Through the development, some preestablished impositions in each field of study are questioned and overcome: 1) the function of stairs in architecture, 2) the reason for the bracing system and the external actions that actually act on them and 3) the determining incidence of the stairs on the overall dynamic and seismic behavior of the building (structural dynamics and seis-mology). The main contribution is to offer, for the first time, an architecture project that provides a transversal solution to the three areas of study. Starting from Le Corbusier's definition, "... architecture is the wise, correct and magnificent game of volumes organized under light¿." Here, the parallelism could be nuanced: "... and of the organized masses in the face of acceleration". The scope of this thesis has been to design buildings in which the main structure and the stairs constitute an effective structural type against the effects of vertical (gravity) and horizontal (wind or earthquake) acceleration loads. The results obtained prove that the integration of the essential elements of the architecture (the main structure and the stairs, in this case) allows creating new, safer, more economical and resilient structural types.

DOCTORAL DEGREE IN ELECTRONIC ENGINEERING

  • GALINDO GUARCH, FRANCISCO JAVIER: DIGITAL HARDWARE ARCHITECTURES FOR BEAM SYNCHRONOUS PROCESSING AND RF SYNCHRONIZATION OF PARTICLE ACCELERATORS
    Author: GALINDO GUARCH, FRANCISCO JAVIER
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN ELECTRONIC ENGINEERING
    Department: Department of Electronic Engineering (EEL)
    Mode: Normal
    Deposit date: 14/04/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: MORENO AROSTEGUI, JUAN MANUEL | BAUDRENGHIEN, PHILIPPE
    Committee:
         PRESIDENT: NUÑEZ YAÑEZ, JOSE LUIS
         SECRETARI: VAZQUEZ GRAU, GREGORIO
         VOCAL: DAMERAU, HEIKO
    Thesis abstract: n Particle Accelerators, the Low-Level RF (LLRF) is the control system of the RF, and in the end, of the purpose of the machine, that is the energy transfer and acceleration of particles. It implements algorithms synchronizing the RF conveying the energy to the beam and tailoring its longitudinal parameters. For this, the LLRF uses beam-related signals whose spectral content changes during the acceleration. The increase in energy results in an increase of the beam velocity, and for circular accelerators (Synchrotrons) a decrease in revolution period. This is especially relevant for Hadron machines whose injection energy is low resulting in a significant increase of their velocity before reaching relativistic speeds. Hence, the LLRF needs to continuously tune its processing to the beam; we call this technique Beam Synchronous Processing. One important task of the LLRF is the compensation of the beam-induced voltage in the accelerating cavities (Beam Loading). In the CERN SPS the regulation bandwidth must cover 5 MHz on each side of the 200 MHz RF. With a beam revolution period around 23 µs more than a hundred revolution frequency harmonics, present in the beam signal, fall in the RF sidebands. The variation in beam velocity changes the position and spacing of the harmonics in the spectrum. The large number of harmonics and their varying positions make the algorithm reconfiguration an undesirable option. To cope with this, the early digital implementations used a system clock derived from the sweeping RF. This locks the sampling and the processing to the beam, by design. This historical solution, that is still in use in several machines, is now a limiting factor for the use of modern technologies.The Thesis presents a novel Beam Synchronous Processing Architecture, using a fixed frequency clocking, and capable of treating periodic signals with known and varying fundamental frequency. The Architecture is an alternative to the burden of reconfiguration in processing algorithms; it tunes the spectrum to the processing by resampling the input data. Two Resamplers are combined in the so-called resampling sandwich. The application algorithm requiring synchronism with the input signal is placed in the middle.The key element is a novel All-Digital Farrow-based Resampler, that accepts arbitrary resampling ratios that can be modified in real-time. The hardware uses a single fixed frequency system clock, making its implementation feasible in State-Of-the-Art FPGAs, ASICs and systems such as the new uTCA platform currently being deployed in the CERN SPS LLRF system. The input and output ports of the Resampler, and all the processing within the Architecture, are synchronous to this fixed frequency clock and accept data streams whose sampling rate can be variable and modified in real time.The Architecture has been commissioned in a LLRF uTCA crate hosting the One Turn FeedBack algorithm to control a real SPS cavity. The algorithm compensates the Beam Loading. The Architecture has demonstrated its capability to track in real-time an energy ramp with an RF frequency following a linear sawtooth pattern ramped at 2.4 MHz per second. The complete uTCA implementation has successfully passed all the functional validation and qualitative tests. The Architecture suits seamless the two technological paradigm changes adopted for the new CERN SPS LLRF system; first, the instantaneous value of the RF frequency is transmitted as a numerical word (used to set the resampling ratio), via a deterministic network, the White Rabbit. And second, the reference signal is now the fixed frequency clock recovered from this network. Both paradigms benefit from the all-digital Resampler and the Beam Synchronous Architecture that fulfil the techniques and technological needs for its implementation enabling novel LLRF algorithms and solutions.
  • YOOSEFI, ORAMAN: Simulation and Design of All-Optical Logic Gates Based on Photonic Crystals
    Author: YOOSEFI, ORAMAN
    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: 14/04/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: RODRIGUEZ MARTINEZ, ANGEL
    Committee:
         PRESIDENT: VILASECA ALAVEDRA, RAMON
         SECRETARI: TIANA ALSINA, JORDI
         VOCAL: MORENO SERENO, MAURICIO
    Thesis abstract: In this thesis,design and simulation of optical logic gases based on different photonics crystals presented to used in the electronics and telecommunication industries. Optical devices perform faster with higher efficiencies compare to the electrical device.The photonic crystal applications to achieve higher transmission power and contrast ratio focus on the design criteria. Results proved promising insights toward the development of gas sensors. The proposed structures have small dimensions as well as a wide functional interval.In Chapter 1,before employing the wavelength-division multiplexing (WDM) method, the notion of the electromagnetic wave in free space and in conductors with a description of equations was defined.Chapter 2 is dedicated to studying literature and similar research,started by the review of photonic crystals and photonic band gap. The gates, characteristics and design layouts were discussed without using nonlinear materials and optical amplifiers.Chapter 3 describes schemes proposed structures.In chapter 4, simulation studies and analysis of six new structures are presented. The procedure is as follows to use the linear logic NOT, OR and AND gates first. These structures have an input waveguide for applying a Gaussian optical pulse at a wavelength of 1550 nm. By changing the radius of the defect, the best dimension with the highest transmission is obtained.Afterward, by coupling these gates, and getting NOR and NAND gates in to study a reasonable contrast ratio and transmission power in each case by changing the defect radius obtained and proved the design concept. A full adder based on metal-insulator-metal (MIM) waveguide-based plasmonic waves. We studied the 4-input OR gate to design and simulate a full adder circuit, which used plasmonic waves to transmit signals; the 4-input gate presented in this study has a simple structure and is manufactured at a low cost. By optimizing the structure's dimensions, the losses and achieve a transmission coefficient of about 0.62 and educe the losses to 25% less than the mentioned design in the references.The next propose structure is a 2DPC based eight channels demultiplexer. This structure is proposed and designed using an octagonal ring resonator for WDM applications.The functional parameters are resonant wavelength, Q factor, channel spacing, spectral width, output efficiency, and crosstalk, are investigated. In this attempt, the channel selection is carried out by altering the octagonal ring resonator's size. The average transmission efficiency, Q factor, spectral width, and channel spacing of the proposed demultiplexer are 98.65%, 2212, 0.76 nm, and 1.75 nm, respectively. The proposed demultiplexer's crosstalk is low (30 dB ) as the even number of channels and the odd number of channels are dropped separately. The demultiplexer's size is about 752.64 µm2, and the functional characteristics of the proposed demultiplexer meet the requirements of WDM systems. Hence this demultiplexer can be incorporated for integrated optics. We have shown that the device is perfectly suitable for communication applications.Chapter 5 is the conclusion of the thesis and recommendation of future studies which has been presented for industrial purposes. In this thesis, a new photonic crystal slab for its use in gas sensing applications is proposed. Theoretical studies have been done to determine the response of the proposed structure to carbon dioxide. A simple laser with around 1 nm spectral widths can be used to simulate this device. Measurements can be done in two steps, which can be done simultaneously by using a reference device: step one with synthetic air and then adding known concentrations of CO.The output is referenced to the measurement with synthetic air.Our theoretical results show that variations of 17% in the transmission intensity and a clear variation on the transmission peaks' central wavelength.These results are already promising for the development of gas s

DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING

  • LI, JUN: Selenium and zinc enriched bioproducts generated from wastewater as micronutrient feed supplements and biofertilizers
    Author: LI, JUN
    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: Change of supervisor
    Deposit date: 18/03/2021
    Reading date: 31/05/2021
    Reading time: 16:00
    Reading place: ETSECCPB - UPC CAMPUS NORD - Videoconferència:
    Thesis director: FERRER MARTI, IVET | DU LAING, GIJS
    Committee:
         PRESIDENT: DE SMET, STEFAAN
         SECRETARI: ROUSSEAU, DIEDERIK
         VOCAL NO PRESENCIAL: LIANG, DONGLI
    Thesis abstract: This thesis aimed to explore the potential of Se/Zn-enriched bioproducts produced from wastewater treatment processes by eco-technologies (phytoextraction, bioreduction and microalgae-based systems) as Se/Zn feed supplements and biofertilizers.In the first part, two aquatic plants (Lemna and Azolla) with substantial protein content were applied to evaluate the possibility of Se and Zn bioaccumulation/removal from wastewater while producing micronutrient-enriched dietary proteins (for feed/food supplements) and biofertilizers. High transformation to organic Se forms and accumulation in plants after taking up Se(IV), together with the high protein content and fast growth rate, makes Lemna (also named duckweed later on) and Azolla good candidates for the production of Se- and Zn-enriched biomass, which can be used as crop fertilizers or protein-rich food/feed supplements or ingredients. The second and third parts, respectively, evaluated the valorization potential of the produced micronutrient-enriched duckweed as well as sludge generated in wastewater treatment processes containing single Se or Se combined with Zn as micronutrient biofertilizers. Micronutrient-enriched sludge dominated by the presence of Se in zero oxidation state (Se(0)) was found to be the preferred slow-release Se biofertilizer and an effective Se source to produce Se-enriched beans for Se-deficient populations, as compared to micronutrient-enriched duckweed. On the contrary, the Zn content in the seeds of beans was not successfully improved through the application of micronutrient-enriched biofertilizers in comparison with the control. This could be attributed to the lower Zn amount applied into soils as Se/Zn-enriched biomaterials. The following experiment explored the potential of Se removal in high rate algae ponds (HRAPs) treating domestic wastewater, while producing high-value Se-enriched biomass. Results indicated that the wastewater treatment performance of the HRAPs was effective. The produced Se-enriched microalgae in HRAPs fed with domestic wastewater contained a high content of crude protein (48% of volatile suspended solids), the selenoamino acid selenomethionine (SeMet) (91% of total Se), and the essential amino acid. The production of Se-enriched microalgae in HRAPs may offer a promising alternative for upgrading low-value recovered resources into high-value feed supplements. The last experiment aimed to evaluate the Se-enriched microalgae generated in the previous experiment as a potential biostimulant to enhance plant growth and as a Se biofertilizer to improve the Se content of plants. This study demonstrated that the application of raw Se-enriched microalgae biomass to soil (1-10%, soil application) and its extracts to leaves (1%, foliar spray) enhanced plant growth, which confirmed that Se-enriched microalgae acts as a biostimulant. Besides, a higher Se content in the plant was achieved after the application of Se-enriched microalgae or extracts thereof. This indicated that Se-enriched microalgae can be valorized as a biostimulant and biofertilizer to improve both the seed yields and Se content of beans, leading to a higher market value of the beans.This thesis contributes to offering an environmentally friendly and sustainable way for micronutrient biofortification/ supplementation in Se/Zn-deficient areas, while recovering nutrients from wastewater.
  • REQUEJO CASTRO, DAVID: Data¿driven Bayesian Networks modelling to support decision¿making: Application to the context of Sustainable Development Goal 6 on water and sanitation
    Author: REQUEJO CASTRO, 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 ENVIRONMENTAL ENGINEERING
    Department: (DECA)
    Mode: Normal
    Deposit date: 16/04/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: GINÉ GARRIGA, RICARD
    Committee:
         PRESIDENT: ESPINO INFANTES, MANUEL
         SECRETARI: VALVENY LLOBET, ERNEST
         VOCAL NO PRESENCIAL: GARCÍA VALIÑAS, MARIA DE LOS ANGELES
    Thesis abstract: We live in a complexand interconnected world which permeates ditterent scales. sectors or decision problems. This fact isacknowledged by the United Nations 2030 Agenda for Sustainable Development, which underscores current globalchallenges, recognizes their interconnectivity and calls for international action. lt is recognized that the connected nature of theissues we currently face have been tackled by "silo" approaches, separating the complexities ofthe real-world intospecialized disciplines. fields of research, institutions and ministries, each one focused on a fraction of the overall truth.Similarly, it is widely recognized the need of a major shift in decision-making processes towards more holistic andintegrated approaches. Evidence-based decrsion-making involves complexprocesses ofconsidering a wide range ofinformation of different nature. Nowadays, available data can support these processes, but methodologies to effectivelyintegrate these data are lacking.With the aim to contribute in this direction, this thesis focuses on the increasing use of Bayesian Networks (BNs) modellingas an approach to accom m odate com plex problem s and to support decis ion-making. Com mon practica em ploys separatelyexpert knowledge and empirical data to build and apply associated models. Des pite of the demonstrated utility of thispractica, in an era where the data are bigger, faster and more detailed than even before, there is still room for furtherexploration. Thus, this dissertation proposes a data-driven Bayesian Networks approach to combine expert opinion andquantitative data to support informad decision-making.We propose two systematic methods to this end. First. we use our approach to replicate composite indicators (Cl)-basedconceptual frameworks, which represent expert knowledge. through the use of structure learning algorithms, whichcharacterizes this data-driven Bayesian Networks approach. Second, we use our approach to identify interlinkagesassociated with a complex context, coupled with a statistical technique (i.e. bootstrapping) to reduce results uncertainty andwith a comprehensive result robustness analysis (i.e. expert knowledge).For testing and validating the proposed approach, this thesis takes the Sustainable Development Goal 6 embedded on the2030 Agenda as a reference point, with particular attention to the water, sanitation and hygier:ie sector.Our results emphasize the likely utility of the data-driven Bayesian Networks approach adopted. First. it allows the integrationof both expert knowledge and data availability when dealing with BNs modelling, and it accurately replicates (Cl)-basedconceptual frameworks. As added values, this combination improves model inference capacity, it reduces and quantifies thekey variables that explµin a pre-defined objective variable (implying important advantages in data updating), and it identifiesthe interlinkages among the variables considerad (which might enhance more integrated actions). Second, the approachadopted is useful to accommodate a thorough analysis and interpretation of the complexities and interdependencias of anycontext at hand. As added values, interlinkages identification is spurred on by the available data and this identification makesthe approach more suitable than the use of composite indicators. Third, the systematic nature of the methodologicalcontributions associated with the proposed approach can be adapted to different complexproblems. Thus, it might expandand deepen the knowledge about the validity, reliability and accuracy of using BNs modelling.

DOCTORAL DEGREE IN GEOTECHNICAL ENGINEERING

  • BARBOZA DE VASCONCELOS, RAMON: A double-porosity formulation for the THM behaviour of bentonite-based materials
    Author: BARBOZA DE VASCONCELOS, RAMON
    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 GEOTECHNICAL ENGINEERING
    Department: (DECA)
    Mode: Normal
    Deposit date: 03/03/2021
    Reading date: 18/05/2021
    Reading time: 11:00
    Reading place: ETSCCPB - UPC Campus Nord - videoconferència: meet.google.com/fgm-vzzb-jem
    Thesis director: GENS SOLE, ANTONIO | VAUNAT, JEAN
    Committee:
         PRESIDENT: VILLAR GALICIA, MARÍA VICTORIA
         SECRETARI: PRAT CATALAN, PERE
         VOCAL NO PRESENCIAL: LLORET CABOT, MARTI
    Thesis abstract: The thermo-hydro-mechanical (THM) behaviour of expansive clays has been extensively studied in the last decades due to the potential use of bentonites as components of engineered barrier systems (EBS) in deep geological repositories for high-level and long-lived radioactive wastes. Since the early post closure period, the EBS is subjected to changes in temperature, moisture content and stresses due to the coupled THM processes expected to occur in such an environment. The different structural levels found in unsaturated expansive clays requires the use of constitutive models that considers the explicit distinction of these pore-structure levels in their mathematical formulation in order to reproduce the development of the fabric of bentonite materials subjected to the complex THM paths taking place during the lifetime of a nuclear waste repository. A coupled THM formulation that represents the expansive soil as two overlapped but distinct structural media has been developed in the framework of classical and generalized plasticity theories. In such a double-structure approach, the THM behaviour of the expansive soil is characterized by constitutive laws formulated to account for the relevant processes affecting each porous medium and for the interaction mechanisms relating the deformation and the saturation states of the active clay particles to the structural arrangement of the clay aggregates and to the water potential in the larger interconnected pores. In addition, the mechanical response of the porous medium to any THM loading is intrinsically related to the compressibility of the clay minerals. The irreversible changes in the soil fabric are attributed to the loading-collapse (LC) mechanism and to the micro-macro structural coupling (ß-mechanism). Thermal effects are incorporated into the mathematical formulation of the double structure model, which has been implemented in a finite element code (CODE_BRIGHT) able to solve, in a fully coupled way, the system of partial differential equations arising from the governing equations (balance equations). An explicit and robust integration scheme with automatic sub-stepping and error control has been employed to update the stress tensor and the internal (history) variables. The capabilities of the implemented double-porosity model to predict the expected response of expansive clays under isothermal and non-isothermal scenarios have been checked by the performance of constitutive analyses following a number of prescribed THM paths under confined and unconfined conditions. In addition, sensitivity analyses have been carried out in order to verify the dependence of the local expansive response on the initial conditions and on the sequence of load application. Special attention has been placed on the role played by the pore-water mass transfer between the two pore-structure levels in the development of the swelling potential of the expansive porous medium. The performance of the model in reproducing the actual THM behaviour of laboratory-scale tests has also been examined by means of the modelling of the hydration of two heated columns made of granular bentonite materials, selected as potential buffer materials in the construction of engineered barriers. The comparison between the available experimental data and the model results has shown the ability of the current double-porosity formulation to simulate the main observed features of the THM behaviour of the expansive material when subjected to complex loading paths.
  • MADRID ARGOMEDO, MANUEL RICARDO: Construction and post-construction performance of vertical breakwaters on soft soils. The Port of Barcelona case
    Author: MADRID ARGOMEDO, MANUEL RICARDO
    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 GEOTECHNICAL ENGINEERING
    Department: (DECA)
    Mode: Normal
    Deposit date: 06/04/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: GENS SOLE, ANTONIO
    Committee:
         PRESIDENT: JOMMI, CRISTINA
         SECRETARI: LLORET MORANCHO, ANTONIO
         VOCAL NO PRESENCIAL: TORRIJO ECHARRI, FRANCISCO JAVIER
    Thesis abstract: The design and construction of vertical caisson breakwaters on soft soils represents a significant challenge for the engineering of marine structures. Past experience reveals that this type of structures is sometimes prone to failure or to undergo excessive settlements. Cyclic loading due to storm wave action adds an addtional degree of complexity. This Thesis present the performance of a wide-ranging set of geotechnical activities to address the key issues of stability, large caisson displacements and cyclic loading effects in the context of the construction of vertical breakwaters. They include site investigation operations (involving laboratory tests, in situ tests and field tests), constitutive models for soft clays (under static and cyclic conditions), instrumentation and monitoring systems, numerical modelling of the breakwater during and after construction and the evaluation of stability under static and cyclic loads. The construction and performance of a vertical breakwater built on the soft soils of the Port of Barcelona provides the focal point to integrate the description of those activities in a joint and structured manner.After reviewing the main aspects associated with the construction and performance of vertical breakwaters, the behaviour of the soft foundation soil is examined. Laboratory tests, in situ tests and a large scale instrumented preload test are considered. Particular attention is paid to undrained shear strength, small strain stiffness, compressibility characteristics and cyclic loading effects. Soil behaviour is then modelled by a range of different constitutive laws of different degrees of complexity. The proper representation of strength anisotropy, long-term creep and cyclic behaviour is explicitly addressed.An extensive monitoring system for the measurement of pore pressures and soil movements has been installed before construction and, following the loss of a number of sensors, after caisson emplacement as well. A novel feature of the instrumentation was the installation of sensors on the front and on the base of the caisson to measure the hydraulic response to the impact of sea waves. The monitoring data has provided the necessary information to achieve a sounder knowledge of the behaviour of the breakwater at different stages of construction and post-construction, including the response under storm loading.Numerical analyses have been carried out towards achieving a better understanding of the breakwater behaviour during construction, post-construction and under cyclic loads. The interplay between monitoring observations, construction history and simulation results is highlighted. Special attention has been given to the evaluation of stability during construction and post-construction. Whenever relevant, the observations provided by the monitoring system are incorporated in the evaluation; the measurement of the evolution of pore pressures has proved important to ensure the safety of the caisson during construction. Breakwater stability under cyclic loading has also been evaluated using both simplified and advanced methods.This ensemble of works performed in the context of a well-documented case history should prove of benefit for the design and construction of similar structures founded on soft ground.
  • TARRAGÓ MUNTÉ, DANIEL: Hydraulic fills liquefaction. Effect on quay stability
    Author: TARRAGÓ MUNTÉ, DANIEL
    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 GEOTECHNICAL ENGINEERING
    Department: (DECA)
    Mode: Normal
    Deposit date: 24/03/2021
    Reading date: 03/06/2021
    Reading time: 09:00
    Reading place: TSECCPB- Defensa per videoconferència per COVID-19 Enllaç:https://meet.google.com/rfu-tfwv-doj
    Thesis director: GENS SOLE, ANTONIO | ALONSO PEREZ DE AGREDA, EDUARDO
    Committee:
         PRESIDENT: GONZALEZ GALINDO, JESUS
         SECRETARI: ARROYO ALVAREZ DE TOLEDO, MARCOS
         VOCAL NO PRESENCIAL: PINEDA, JUBERT
    Thesis abstract: The starting point of this thesis is the failure of part of a quay wall under construction. The quay was divided in two phases, failure affected Phase 1 only. The failure and all the relevant associated information on quay design, construction and monitoring records are described in detail together with the results of a site investigation campaign carried out after the failure. Flow liquefaction of the hydraulic fill emplaced behind the quay wall was the main cause of the failure. The state of the hydraulic fill in the quay area is assessed in the light of the current understanding of the phenomenon and of a number of flow liquefaction criteria. In addition, an elastoplastic constitutive law is described that is capable to simulate the undrained brittleness behaviour that underlies the phenomenon of flow liquefaction. It is a critical-state model that incorporates the concept of state parameter. Subsequent finite element analyses are able to reproduce satisfactorily the behaviour of the quay during construction and the features and circumstances of the failure. Two possible triggering mechanisms are identified that can explain the failure: spontaneous liquefaction, or liquefaction of a limited zone caused by the concurrent construction of an embankment. A parametric study verifies the robustness of the simulation and the dependence of stability on the degree of brittleness of the hydraulic fill. The same type of analysis of quay Phase 2, not involved in the failure, revealed that the margin of safety was small if the hydraulic fill liquefied. Soil improvement measures were implemented and an extensive monitoring system was installed. Construction of quay Phase 2 was completed applying the observational method that involved a continuous check of the monitoring data and its comparison with numerical simulation results. An additional site investigation confirmed that the soil improvement measures had succeeded in removing both the flow and the cyclic liquefaction potential of the hydraulic fill, according to currently accepted criteria. The Phase 1 quay involved in the failure was reconstructed with mainly terrestrial fill with no flow potential liquefaction, as confirmed by the corresponding site investigation. Based on the experience gathered in the case and on the research carried out, an operational scheme dealing with quays constructed with hydraulic fills susceptible to flow liquefaction is proposed. It consists of a protocol to evaluate liquefaction potential of hydraulic fills, the use of a constitutive law capable of simulating flow liquefaction, the implementation of soil improvement measures to reduce flow liquefaction potential and the employment of a monitoring system to control the quay wall behaviour during construction and to provide data for comparison with numerical analyses results.
  • TRABUCCHI, MICHELA: Hydrodynamics and Geochemistry at Multiple Scales: Characterizing Preferential Flow-Paths and Wormholes in Evaporitic Sediments
    Author: TRABUCCHI, MICHELA
    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 GEOTECHNICAL ENGINEERING
    Department: (DECA)
    Mode: Normal
    Deposit date: 08/04/2021
    Reading date: 11/05/2021
    Reading time: 15:00
    Reading place: ETSECCPB- Defensa per videoconferència per COVID-19 Enllaç meet: https://meet.google.com/sms-tghs-aia
    Thesis director: CARRERA RAMIREZ, JESUS | FERNANDEZ GARCIA, DANIEL
    Committee:
         PRESIDENT: RIVA, MONICA
         SECRETARI: SANCHEZ VILA, FRANCISCO JAVIER
         VOCAL NO PRESENCIAL: COPTY, NADIM
         VOCAL NO PRESENCIAL: GOLFIER, FABRICE
         VOCAL NO PRESENCIAL: LUQUOT, LINDA
    Thesis abstract: The characterization of evaporitic aquifers for a better understanding of hydrodynamics and geochemical processes is of great importance, especially in environments where both the sustainability of unique ecosystems and the economic interests depend on aquifer features. This is the case of the Salar de Atacama (SdA) evaporitic nucleus, the "driving force" of this thesis, which prompt us to pursue two main objectives. First, characterizing the hydraulic behavior of the SdA nucleus, with special attention for the identification of highly connected structures (preferential flow-paths). Second, enriching the knowledge on preferential flow-paths development caused by dissolution processes (i.e. wormholes dynamics) and the corresponding changes in flow and transport behaviour.As a first step, we focused on the interpretation of hydraulic tests for aquifer characterization. Agarwal's method for recovery test interpretation was selected as suitable for analyzing the SdA aquifer response to imposed stresses for hydraulic properties estimation. Thus, we verified the method under ideal and non-ideal condition and we exposed its limitations. The latter were overcome by modifying the existing methodology and proposing an improved equivalent time to deal with variable pumping rates.At the same time we carried out a long-lasting cross-hole hydraulic test in the SdA nucleus. The complexity of system dynamics highlighted the need of seeking for a different methodology for aquifer characterization. We ended up developing a new filtering-corrective method through which aquifer characterization was carried out. The method involves estimating drawdowns, corrected from eventual systematic and structural errors, to be used as observations while automatically calibrating a groundwater model.Once validated the new method, we applied it, jointly with the stochastic inversion, to characterize the SdA nucleus in terms of spatial variability of the hydraulic conductivity at a large scale, with special attention for identifying connectivity structures. Results showed that these structures actually govern flow dynamics at large scale. Their identification was supported by independent information, which was used to verify the consistency of the results, thus the capability of the stochastic inversion in defining preferential flow-paths at large scale.Finally, we moved to an intermediate-scale analysis, carrying out a laboratory experiment under controlled conditions. We ran a dissolution experiment, jointly with several tracer tests, to study the evolution of a dissolution pattern characterized by dominant wormholes. We analyzed the evolution of wormhole dynamics, with special attention for wormholes growth, changes in hydraulic properties, geometry and competition for the flow. Furthermore, by interpreting the tracer tests we were able to quantify the effect that these structures have on the hydraulic and transport behavior. For that, we applied the multi-advection dispersion model, considering two modelling approaches: by fitting the measured BTCs with effective transport parameters and by predicting the BTCs evolution through a discrete wormhole modelling approach, applied knowing the geometry of the system and transport parameters of the undissolved matrix. Both approaches are capable of reproducing the experimental data, highlighting the ability to characterize the system. Results also demonstrate the high predictive power of the discrete wormhole model.

DOCTORAL DEGREE IN MATERIALS SCIENCE AND ENGINEERING

  • BESHARATLOO, HOSSEIN: Micromechanical properties of inorganic multiphase materials
    Author: BESHARATLOO, HOSSEIN
    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: 03/03/2021
    Reading date: 13/05/2021
    Reading time: 11:00
    Reading place: Escola d'Enginyeria de Barcelona Est - Campus Diagonal-Besòs - videoconferència: https://meet.google.com/yvk-ugwq-gup
    Thesis director: LLANES PITARCH, LUIS MIGUEL | ROA ROVIRA, JOAN JOSEP
    Committee:
         PRESIDENT: RINALDI, ANTONIO
         SECRETARI: JIMENEZ PIQUÉ, EMILIO
         VOCAL: MSAOUBI, RACHID
    Thesis abstract: This thesis is dedicated to understanding the micromechanical properties of multiphase materials which are indispensable in today¿s engineering applications. The mechanical behavior of these materials is dictated by the intrinsic response of each constitutive phase as well as the fashion in which they interact with each other. Therefore, an accurate assessment of both microstructural characteristics and small-scale mechanical properties becomes key for understanding the macroscopic behavior of these materials.Within the above context, the current study is intended to offer a systematic investigation, aiming to assess small-scale mechanical properties of multiphase materials through a protocol based on massive nanoindentation and statistical analysis. It consists of three sequential stages: (1) microstructural characterization, (2) micromechanical evaluation (massive indentation and statistical analysis), (3) correlation between microstructure and mechanical properties using advanced characterization techniques.Microstructural characterization of studied systems was carried out through extensive field emission scanning electron microscopy analysis. This is an essential step for determining testing parameters to be used when implementing massive indentation, particularly penetration depth of performed imprints. Based on the acquired information, massive indentation testing and statistical analysis of experimentally gathered data were implemented to determine the local properties of several unidentified phases. Such data analysis was then complemented by the use of different advanced characterization techniques for deeper inspection of microstructural features. Main goal of this final step was to define the unidentified mechanically distinct phases, based on physically- based correlations between microstructure features and small-scale properties.The proposed and described protocol has been implemented on three different materials: Duplex Stainless Steels (DSS), Polycrystalline cubic Boron Nitride (PcBN) composite and Ti(C,N)-FeNi cermets. They are representative of metal-metal, ceramic- ceramic, and ceramic-metal systems, respectively.Regarding DSS, the influence of the processing route on the local mechanical properties (hardness (H) and elastic modulus (E)) of ¿ and a phases of a DSS was successfully evaluated. Moreover, a novel 2D histogram of hardness and elastic modulus was introduced and validated as an effective tool to correlate microstructure and intrinsic mechanical properties of the constitutive phases of DSSs.PcBN composite consists of cBN particles embedded within a TiN binder. The correlation of relative B/N ratio and local hardness for individual cBN particles was studied, through complementary analysis using electron probe X-ray microanalysis of the data attained using the proposed methodology.The influence of ceramic/metal phase ratio and C addition on the local hardness of Ti(C,N)¿FeNi cermets have been assessed. Regarding the small-scale properties of the constitutive phases, the intrinsic hardness of both Ti(C,N) particles and FeNi binder were determined using the suggested testing procedure.It has been proven that the proposed methodology can be considered as a successful testing protocol for determining small-scale mechanical properties (H and E) of the studied multiphase systems. Nevertheless, successful implementation requires careful consideration of testing parameters used, based on microstructural, residual imprint, and plastic flow length scales.
  • KAMRANI MOGHADAM, MOHAMMAD REZA: Preparation and characterization of reactive extrusion modified PLA/ABS blends and its foams
    Author: KAMRANI MOGHADAM, MOHAMMAD REZA
    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: 23/03/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: SANCHEZ SOTO, MIGUEL ANGEL | CAILLOUX, JONATHAN
    Committee:
         PRESIDENT: LÓPEZ MARTÍNEZ, JUAN
         SECRETARI: MASPOCH RULDUA, MARIA LLUÏSA
         VOCAL: CASTILLO LÓPEZ, GERMAN
    Thesis abstract: The current thesis takes place within the context of the projects MAT2016-80045-R "Aplicaciones industriales de compuestos y mezclas basados en REX-PLA" and the project "PLAIABS Blends: Recydability and weight reduction" financially supported by the Ministerio de Economía y Competitividad of the Spanis h Government and SEAT res pectively.The main objective was to improve the properties of poly lactic acid (PLA) in arder to make it suitable for long-lasting applications where emphasis is de\Qted to the reduction of carbon dioxide emissions and the renewable raw materiaIs content. Among the different routes to enhance PLA properties, blending was used, as it is easily scalable bythe industry. Dueto its good balance of properties, ABS was considered a suitable polymer to be used together with PLA However, dueto their immiscibili ty, a coupling agent (ABS-g -MAH) was introduced.Apart of brittl ness, another PLA problem is its relatively easy degradation during process ing. Previous studies of the Group indicated that PLAdegradation could be limited using a multi epoxide reactive agent that a110ids the loss in molecular weight and increases the PLA melt visc osity, which, on the other hand, facilitates processing . Moreover, it was believed that the unreacted chain extender epoxide groups could also form covalent bonding with the coupling agent improving ABS and PLA compatibility.Using foams both the total weight and carbon dioxide generation of components can be diminished. For these reasons, different techniques for physicallyfoaming the blends either during injection (MuCell) or through a batch process were object of research. The effect of the above mentioned chain extender and the effect of a tale filler on the batch-foaming behavior of PLAwas studied.The first step of the research consisted in obtained the base materiaIs by reactive extrusion (REX) at a pilot plant seale (50 kg.). A conventional injection molding process was then employed to obtain standard samples that were used for the thermo­ mechanical characterization ofthe blends.The thermal stabilitywas studied bythe Kissinger 's method. The results showed that it was improved when the amount of ABS-g-MAH was increased. From the DSC analysis, it was found that in comparison to more perfect REX-PLA structures, crystals with a smaller lamellar thickness were formed in the blends. The differences in crystallinitywere small and do not influence the mechanical properties. The presence of ABS in the compositions led to a decrease ofthe blend 's storage modulus. Nonetheless, the ABS phase was found to playthe role of scaffold for the PLA phase that can undergo re­ crystallization, being thus able to support a certain amount of loading during heating.The physical foaming ofthe different injected blends was difficult to be achieved. The optimization ofthe foaming conditions required several triaIs and a large quantityof material. As the amount of each blend was limited, only a partial number of the proposed experiments were possible. The obtained blends contained a few large cells as well as a certain population of small sized cells. Although a complete micro-cellular structure was not achieved, the obtained one was similar to that of previous works found in literature. lt was, however, demonstrated that this technique can be used byindustryto generate lighter components.Batch foaming using CO2 in supercritical conditions resulted in successful foams with cell sizes below 100 microns and very high cell densi ties. In comparison to PLA, dueto its higher viscosity and melt resistance, using REX-PLA resulted in improved level offoaming which prevents from cell coalescence and collapse. The presence of ABS in the blends allowed broadening the range of pressure and temperatures in which foams can be produced. Tale was found to actas a nucleating agent leading to smaller cell sizes and higher cell densities in the foamed blends.

DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING

  • BOSSIO, MATIAS ALBERTO: Análisis de la respuesta dinámica en agitadores industriales
    Author: BOSSIO, MATIAS ALBERTO
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
    Department: Department of Fluid Mechanics (MF)
    Mode: Confidentiality
    Deposit date: 16/04/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: VALERO FERRANDO, MARÍA DEL CARMEN | VALENTIN RUIZ, DAVID
    Committee:
         PRESIDENT: SANTOLARIA MORROS, CARLOS
         SECRETARI: PRESAS BATLLÓ, ALEXANDRE
         VOCAL: BARRIO PEROTTI, RAUL
    Thesis abstract: In food and pharmacological industries, reducing the production time and improving the machine flexibility to be adapted to new products is a constant necessity. This generate changes on the initial working conditions for which the machines were designed. These conditions cause alterations on its dynamic response that can lead to structural failures. To detect the earliest signs of damage of the different elements of the machines makes possible to avoid unplanned downtimes and the economic losses that this involves.The use of agitators at these types of industries is common. The agitators are rotating machines composed for one or several blades, working with different types of fluids and with a wide range of shapes. The company Vak Kimsa S.A., with 48 years of history, has consolidated its position in recent years as agitators and in-line mixing manufacturer, being a leader in the national market. Due to the continuous development of new technologies, their integration to the industry and the increasing demand for competitive products, the company raise a long-term project to take its products to the next level. The objective is to be able to offer an agitator¿s monitoring service in order to avoid unplanned downtimes. Analysing, from the vibrational point of view, the state of the elements that compose the agitator and being able to stablish alarms according to this.The study is part of an Industrial Doctorate together with the CDIF (Centre for Industrial Diagnostics and Fluid Dynamics) of the UPC of Barcelona. The whole project has been financed by the Government of Catalonia, thanks to the funds earmarked for Industrial Doctorate projects.The objectives and the methodology used to carry out the project are detailed in this document. The experimental test, numerical simulations and the subsequent data analysis are explained, as well as the new knowledge obtained by the company in terms of the dynamic behaviours of the agitators and the use of new technology. Finally, and based on this, the minimum hardware and software are established in order to perform the monitoring service.
  • REINA GUZMÁN, WASHINGTON SALVATORE: Contribución a la metodología de caracterización dinámica de materiales resilientes para aplicaciones ferroviarias
    Author: REINA GUZMÁN, WASHINGTON SALVATORE
    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: 11/03/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: ARCOS VILLAMARÍN, ROBERT | CLOT RAZQUIN, ARNAU
    Committee:
         PRESIDENT: CARRASCAL VAQUERO, ISIDRO ALFONSO
         SECRETARI: PÀMIES GÓMEZ, TERESA
         VOCAL: DE ARCAS CASTRO, GUILLERMO
    Thesis abstract: This thesis is focused on the enhancement and development of advanced methodologies for the dynamic characterisation of resilient elements used in railway applications. On the one hand, this thesis proposes several improvements to the application of the indirect method described in ISO 10846 standard for determining the dynamic stiffness of resilient elements using a swept-sine excitation. Within this framework, this work proposes a method that allows to design the swept-sine excitation parameters in order to ensure a predefined maximum error of those estimated frequency response functions that are needed to determine the dynamic stiffness. This method is based on a procedure that uses a numerical simulation of the test-rig and the resilient element of study which allows to predict the error made as a function of the excitation parameters and of the existing background noise, allowing to optimise the test in terms of required time and results quality. The method is then validated experimentally for two case studies: a sample of an elastomeric material and a coil spring. This work has also studied the influence that the experimental setup, the static preload and the dynamic loading have on the estimation of the frequency response functions. On the other hand, this thesis considers the adaptation of an existing in situ methodology to laboratory testing. The methodology allows to determine the dynamic stiffness of an elastic element in a broad frequency range with a single test. This alternative methodology has been validated using the two case studies previously mentioned. By including the improvements made to the indirect method to this methodology, it is possible to obtain a simple and robust method that can take into account the uncertainty related to several effects such as the excitation, the background noise and the experimental setup. Finally, the dynamic stiffness results obtained for both case studies have been compared to the results obtained using standardised methods such as the direct and indirect methods. From these comparisons it can be concluded that the proposed alternative method is the best choice to determine the frequency dependence of the dynamic stiffness, specially at high frequencies, as it allows to perform a broad-band characterisation in a single test and it overcomes the problems induced by the inertia forces found when the direct method is applied at high frequencies.

DOCTORAL DEGREE IN NUCLEAR AND IONISING RADIATION ENGINEERING

  • COELLO DE PORTUGAL - MARTINEZ VAZQUEZ, JAIME MARIA: Local Optics Corrections in the HL-LHC
    Author: COELLO DE PORTUGAL - MARTINEZ VAZQUEZ, JAIME 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 NUCLEAR AND IONISING RADIATION ENGINEERING
    Department: Institute of Energy Technologies (INTE)
    Mode: Normal
    Deposit date: 17/03/2021
    Reading date: 16/06/2021
    Reading time: 11:00
    Reading place: ETSEIB_ Defensa per Videoconferència per COVID-19 Meet: https://meet.google.com/ynt-qsjz-zpi
    Thesis director: TOMAS GARCÍA, ROGELIO | KOUBYCHINE MERKULOV, YOURI ALEXANDROVICH
    Committee:
         PRESIDENT: PEREZ RODRIGUEZ, FRANCISCO JOSE
         SECRETARI: CORTES ROSSELL, GUILLEM PERE
         VOCAL: DALENA, BARBARA
    Thesis abstract: In order to increase the performance of particle colliders, it is crucial to make the beam sizes at the collision points as small as possible. This causes an increase of the beam size in the region surrounding the collision points thus enhancing the effect of magnetic errors. These errors must therefore be kept under tight control to ensure the performance and safety of the accelerator.The present thesis studies effects of the expected magnetic errors in the regions around the collision points on the beam optics that determine the beam size in the future High-Luminosity upgrade of the Large Hadron Collider (HL-LHC), a 27 km particle accelerator situated on the French-Swiss border near Geneva, Switzerland. It has become clear in recent years that in correcting the magnetic errors in this region a crucial requirement is an accurate measurement of the beam optics at the collision point. This thesis demonstrates that the technique used traditionally in recent years, called ¿K-modulation¿, is not accurate enough to ensure the performance of the HL-LHC and therefore alternative methods of performing this measurement must be studied.To perform these studies a new automatic optics correction tool has been developed and is presented in this thesis. This new tool allows faster and more systematic calculation of corrections of the magnetic errors around the interaction regions and has been successfully tested during commissioning and experiments in the LHC.Two complementary techniques are proposed in order to improve the accuracy of the determination of the beam sizes at the collision points, namely determining the minimum beam size near the collision point using the ¿phase-advance¿ of the beam oscillations around the accelerator and locating the position of this minimum, the ¿beam waist¿, by displacing it and maximising the collision rate characterized by the collider luminosity. In the thesis these techniques are studied theoretically, and the first results of their experimental validation performed in the LHC are presented.This push for smaller beam sizes at the collision points not only increases the beam sizes in sections around this point but also, though to lesser degree, in the arcs of the accelerator. These regions also become susceptible to smaller magnetic errors. As some regions of the accelerator do not count with adequate corrector magnets alternative solutions are needed. Here we present the first experimental results of an optics correction performed by traversing sextupoles with off-central beam in the LHC as a solution proposal. Another consequence of the growth of the beam sizes in the regions around the collision points is the eventual necessity for larger beam pipes. This is the case for HL-LHC where the magnetic lenses around the collision points are going to be replaced by new ones with the beam pipe of larger diameter. In order to keep the same magnetic strength though a new superconducting technology is going to be used to build these magnets. A downside of this novelty is that it is susceptible to a type of magnetic instability called ¿flux-jumps¿. In the thesis the effect of the flux-jumps on the beam sizes is studied theoretically and concrete predictions using measurements of this effect on the prototypes of the new magnets of the HL-LHC are given. The study is also extrapolated to the Future hadron-hadron Circular Collider (FCC-hh), a proposed 100 km circular collider, in which superconducting magnets of this type are expected to be installed all around its circumference.Finally, the thesis presents a summary of software developments performed during the previously mentioned studies, including a user interface to facilitate the use of the automatic correction tool, a new harmonic analysis program that replaces legacy code and many refactors and rewrites that have significantly eased the development of the optics measurements and corrections programs.

DOCTORAL DEGREE IN STATISTICS AND OPERATIONS RESEARCH

  • CORTÉS MARTÍNEZ, JORDI: Constant effect in randomized clinical trials with quantitative outcome. A methodological review.
    Author: CORTÉS MARTÍNEZ, JORDI
    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 STATISTICS AND OPERATIONS RESEARCH
    Department: Department of Statistics and Operations Research (EIO)
    Mode: Normal
    Deposit date: 19/04/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: COBO VALERI, ERIK | GONZÁLEZ ALASTRUE, JOSÉ ANTONIO
    Committee:
         PRESIDENT: SORRIBAS TELLO, ALBERTO
         SECRETARI: PEREZ ALVAREZ, NURIA
         VOCAL: CATALÁ LÓPEZ, FERRAN
    Thesis abstract: The past decade has seen continuous growth in so-called precision medicine, due especially to great advances in the genetics. While applying it presently goes unquestioned in certain fields like oncology, it is more controversia! in other medical specialties that usually practice it. Precision medicine is justified under two assumptions. First, it must be more cost-effective than the universal standard of care, as a world with limited resources requires that an individual treatment's benefits be inversely related to the number of people on whom it is effective. Second, and most importantly, the intervention under study should actually show different responses among patients or subgroups of them, which this work focuses on. Strictly speaking, the fundamental problem of causal inference makes the latter requirement impossible to prove, because a conventional trial observes patient outcome only under a single treatment. However, the variability of a continuous outcomeprovides important information about the presence (or absence) of a constant treatment effect, of which a direct consequence is that outcome variance remains unchanged under different treatment regimens. Thus, homoscedasticity may be a useful tool for testing the hypothesis of a homogeneous effect.Our work here conducts a methodological review of randomized clinical triaIs (RCT) with two ·treatment arms and a quantitative primary end point. Among other variables, we collected the outcome and baseline variances for each treatment group with two purposes: to quantify the outcome variance ratio between the experimental and reference groups; and to estimate the proportion of studies with variance discrepancies large enough to be attributed to a heterogeneous treatment effect among participants. This variance comparison was carried out between treatment arms (independent by randomization) and overtime, contrasting the end-of-study and baseline outcomes.The Medline database provided us 208 randomized clinical trials fulfilling the eligibility criteria and published in the years 2004, 2007, 2010 and 2013. A random effects model was used to estimate the variance ratios (experimental to reference), of which the mean was 0.89, 95% CI from 0,81 to 0,97. Thus, contrary to popular belief, the point estimate indicate that the experimental treatments reduce the variability of patient response by 11%. The experimental group's variance ratio (final to baseline) in the comparison over time was 0,86, 95% CI from 0,76 to 0,98, meaning lower variability at the end of the study. This analysis provides no statistical evidence to justify ruling out a constant intervention effect on our target population in four out of five studies (80,3%, 95% CI from 74,1 to 85,3%). This percentage barely changed in four sensitivity analyses with percentage point estimates ranging from 79,8 to 90,0%. Among the studies that we found evidence of a non-constant intervention effect, the experimental group showed 7,2% and 12,5%, respectively, greater and lower outcome variance than the reference arm. The high number of studies with lower variability in the experimental group can be explained by the ceiling and floor effects of sorne measurement scales, which generally group patients at one of the scale boundaries in cases of highly effective interventions.This work aims to show that comparing variances provides evidence on whether ar not precision medicine is a sensible choice for a specific treatment. When both arms have equal variances, a simple interpretation is that the treatment effect is constant. lf true, searching for any predictors of a differential response is futile. This means that the average treatment effect can be viewed as an individual treatment effect, which justifies using a single clinical guideline for all patients fulfilling the eligibility criteria. This in turn supports using parallel controlled trials to guide decision-making in these circumstances.
  • MOLINS LLEONART, EDUARD: Proposing some innovative study design features to regulatory agencies (EMA and FDA) in bioequivalence trials. Reference Scaled Average Bioequivalence, and Two-Stage Adaptive Designs
    Author: MOLINS LLEONART, EDUARD
    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 STATISTICS AND OPERATIONS RESEARCH
    Department: Department of Statistics and Operations Research (EIO)
    Mode: Normal
    Deposit date: 14/04/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: OCAÑA REBULL, JORDI
    Committee:
         PRESIDENT: GÓMEZ MELIS, GUADALUPE
         SECRETARI: DEL CASTILLO FRANQUET, JOAN
         VOCAL: KARALIS, VANGELIS
    Thesis abstract: In applications for generic medicinal products the concept of bioequivalence is fundamental. Two medicinal products, i.e. a test and a reference drugs containing the same active substance are considered bioequivalent if their bioavailability (rate and extent of absorption of an active substance that is absorbed from a drug product and becomes available at the site of action) after the administration of both products produce a similar therapeutic effect. The assessment of bioequivalence is based upon 90% confidence intervals for the ratio of the population geometric means (test/reference) for the parameters under consideration which should be contained within the limits 80%-125%. It is recommended using randomized, two-period, two-sequence, single dose crossover designs (2x2 crossover designs)The number of subjects to be included should be based on an appropriate sample size calculation, though the number of evaluable subjects should not be less than 12. Sometimes, there are drugs whose rate and extent of absorption is highly variable dose to dose within the same subject. The main problem with highly variable drugs is that to declare bioequivalence it requires a study with an unacceptably larger sample size. In this case, the usual approach to determine bioequivalence is `Reference Scaled Average Bioequivalence¿ (RSABE), which is based on expanding the limits as a function of the within-subject variability in the reference formulation. But, using 2x2 crossover designs, it is not possible to estimate separately the test and reference variabilities, and thus it requires using more complex designs like replicated or semi-replicated crossover designs.On the other hand, regulations also allow using common 2×2 crossover designs based on two-stage adaptive designs (TSD) with sample size re-estimation at an interim analysis. At an interim look (stage 1), if average bioequivalence is not declared with an initial sample size, they allow to increase it based on the intra-subject estimated variability and to enroll additional subjects at a stage 2, or to stop for futility in case of poor likelihood of bioequivalence. This is crucial because both parameters must clearly be pre-specified in protocols, and the strategy agreed with regulatory agencies in advance with emphasis on controlling the overall type I error.Using Monte Carlo simulations, we show that RSABE and TSD methodologies achieve comparable statistical power, though the scaled method usually requires less sample size, but at the expense of each subject being exposed more times to the treatments. With an adequate initial sample size (not too low, e.g., 24 subjects), TSDs are a flexible and efficient option to consider: They have enough power (e.g., 80%) at the stage 1 for non-highly variable drugs and, if otherwise, they provide the opportunity to step up to a stage 2 that includes additional subjects.Based on TSDs, we also present an iterative method to adjust the significance levels at each stage which preserves the overall type I error for a wide set of scenarios which should include the true unknown variability value, and which provides a power of at least 80%. TSDs work particularly well for coefficients of variation below 0.3 which are especially useful due to the balance between the power and the percentage of studies proceeding to stage 2. We present an R package to adjust the significance levels at each stage in order to control the overall type I error.

DOCTORAL DEGREE IN THEORY AND HISTORY OF ARCHITECTURE

  • AUBÁN BORRELL, MÓNICA: Memorias de la ciudad sin historia. La importancia de los afectos en la construcción y en las vivencias del barrio de La Mina
    Author: AUBÁN BORRELL, MÓNICA
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN THEORY AND HISTORY OF ARCHITECTURE
    Department: (THATC)
    Mode: Normal
    Deposit date: 20/04/2021
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: LLORENTE DIAZ, MARTA
    Committee:
         PRESIDENT: MEJÍA VALLEJO, CLARA ELENA
         SECRETARI: BITRIÁN VAREA, CARLOS
         VOCAL: MIRAS BORONAT, NÚRIA SARA
         VOCAL: LAGUILLO MENÉNDEZ, MANUEL
         VOCAL: SERRA PERMANYER, MARTA
    Thesis abstract: In 1959, in the context of urban growth promoted by the `Plan Comarcal¿, the so-called `Plan Parcial de La Mina¿ was approved, and a new neighbourhood was expected to be built on the right bank of river Besòs area. However, it was only in 1968 that construction began, and only in 1972 the definitive project was finally set. A reason that explains both the delay and the frequent changes introduced in the urban planning can be found in the decision of using La Mina as one of the main destinations for `barraquistas¿ or slums-dwellers in Barcelona. From an architectural perspective, the role that La Mina assumed in the campaign against shacks entailed a series of adjustments, reductions and rashness that, shortly afterwards, would pose a risk to habitability conditions in the new neighbourhood. From a symbolic perspective, the bound that linked La Mina to the most despicable urban form in the history of Barcelona involved maintaining unfair stereotypes and negative characteristics traditionally assigned to the population from slums areas.Considering the mentioned link as the principal axis of the reflection, this thesis proposes to explore the vague edges that separate the architectural structure of La Mina from its imaginary and from the quotidian experience of living in the neighbourhood. How have words, narratives, news, the media and photographs referring to La Mina influenced its process of spatial conformation? How have the representations of this place altered its current perception? What traces from past `barracas¿ remain in this peripheral landscape? Why does La Mina continue to be identified as a paradigm of urban marginality almost fifty years after its construction?During the whole research period, the aim to find answers to these questions has been guided by two basic premises. On the one hand, the importance of reassembling the history of the neighbourhood with a special focus on materials, both textual and graphic, preserved from La Mina and the near slum settlement El Camp de La Bota. On the other hand, the decision to introduce affection in the process of analysing and re-reading signs and traces left by imaginary and quotidian experience in the spatial structure of La Mina. Even though they have generally been excluded from architectural frameworks, not only fear, disdain and shame, but also pride and the sense of belonging or place attachment are essential dimensions when one tries to face the complexities and contradictions that define life in the neighbourhood of La Mina. Thus, history and affect have allowed building a firm base from which to look once more to La Mina leaving aside hackneyed topics and confronting all the questions, challenges and limits that this particular territory offers to the disciplines of Architecture and Urbanism.

DOCTORAL DEGREE IN TRANSPORT ENGINEERING AND INFRASTRUCTURE

  • MEDINA TAPIA, MARCOS: Urban Mobility Network Design. Functional Analysis and Modeling for a Concentric City
    Author: MEDINA TAPIA, MARCOS
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN TRANSPORT ENGINEERING AND INFRASTRUCTURE
    Department: (DECA)
    Mode: Normal
    Deposit date: 26/03/2021
    Reading date: 15/06/2021
    Reading time: 16:30
    Reading place: VIDEOCONFERENCIA Estat alarma Covid-19 - ETSECCPB, aula C2-001 enllaç:meet.google.com/cyg-nkzv-xai
    Thesis director: ROBUSTÉ ANTÓN, FRANCESC
    Committee:
         PRESIDENT: MONZÓN DE CACERES, ANDRÉS
         SECRETARI: ESTRADA ROMEU, MIGUEL ANGEL
         VOCAL: DELL\'OLIO, LUIGI
    Thesis abstract: Cities face problems influencing urban mobility, such as traffic growth, congestion, explosive population growth, urban sprawl. According to the literature, traffic, congestion, and urban development have an interrelationship with each other; traffic is a function of the system of activities attracting travel; activities define urban development and, its planning determines the traffic level and congestion. Thus, urban development requires a simultaneous interaction of its urban structure and transportation systems, contributing to urban mobility efficiency.The research proposes how to adapt infrastructure and land uses to meet the needs for traveling in a city. The above question promotes a balanced design between transportation networks, population distribution, land use, and infrastructure. The main objective is to develop a macroscopic method to identify infrastructure requirements reaching an appropriate service level for mobility and transportation.The methodology bases its formulation on analytical models to deduce critical components of a structural network for a concentric city, considering many dispersed cities set to this urban scheme. These key components must ensure the critical conditions of public and private transportation infrastructure. The Continuous Approximation (CA) method solves the problem based on local cost by using variables defined as densities.The dissertation focuses its research on urban design based on functionality, the role of heterogeneous distributed demand, and design effects on urban structure. The application of the model and obtained results focus on three types of analyzes. First, theoretical case analysis, considering both public and private transportation (multi-subcenter cities reduce total costs between 2.6 and 11.6%). Second, the analysis of a planning measure (subcenters save 3.5% of total costs) and new transportation technology (autonomous vehicles could neutralize the reduction in travel costs and times). Third, the model application to a current city such as Santiago of Chile (the system optimization advises an increment in subway services).Finally, the model, its implementation, analysis, and results prove that it is a promising contribution to planning science. In practice, its application can provide robust approaches to elaborate spatial planning instruments.Keywords: Urban mobility; Network design; Public Transportation; Private Transportation; Continuous approximation; Concentric city; Urban subcenters; Autonomous vehicles; Santiago, Chile.

NAUTICAL ENGINEERING, MARINE AND NAVAL RADIOELECTRONICS

  • JURADO GRANADOS, JOEL: Desarrollo e implementación de una formulación utilizando la teoría de mezclas serie/paralelo para la modelización de estructuras navales de materiales compuestos sometidas bajo cargas cíclicas
    Author: JURADO GRANADOS, JOEL
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: NAUTICAL ENGINEERING, MARINE AND NAVAL RADIOELECTRONICS
    Department: Department of Nautical Sciences and Engineering (CEN)
    Mode: Normal
    Deposit date: 24/03/2021
    Reading date: 10/05/2021
    Reading time: 16:00
    Reading place: Facultad de Náutica de Barcelona - Pla de Palau, 18, 08003 Barcelona - videoconferència: https://meet.google.com/yxe-mhid-viw
    Thesis director: MARTINEZ GARCIA, JAVIER | DI CAPUA, DANIEL
    Committee:
         PRESIDENT: PAREDES LÓPEZ, JAIRO ANDRÉS
         SECRETARI: OTERO GRUER, FERMÍN ENRIQUE
         VOCAL: KADIYALA, AJAY KUMAR
    Thesis abstract: The main goal of this thesis is the simulation of the performance of composite naval structures subjected to cyclic loads. The predicted behavior expected is the fatigue life of the composite structure, as well as the fatigue failure mechanisms. This achievement is conducted by coupling the serial/parallel mixing theory and a fatigue damage model. Consequently, the work has the following stages.In first place, a study is conducted in order to identify the failure mechanisms of composites in fatigue and how the different factors affect it, in order to propose a fatigue constitutive model for fibre and matrix. The review uses a constituent materials point of view, thus fatigue performance of fibres and resins are analyzed, as well as their role in each failure mechanisms. In addition, different variables that may affect fatigue behavior are described.Secondly, a numerical procedure for characterizing fibres and matrix is proposed, in order to predict the failure mechanisms in composites subjected to static loads. The procedure defines which experimental tests should be conducted and what material parameters are obtained from them. As a consequence, the material parameters of the constituent materials are defined, obtaining the failure of the composite by the failure of the constituent materials, without pre-defining the expected failure.The next stage is coupling the serial/parallel mixing theory and the fatigue model. The fatigue model modifies the constitutive equation of the components, while the rule of mixtures acts as a constitutive law manager. The fatigue models of fibre and matrix are characterized, assuming that the fatigue behavior of unidirectional laminates is driven by one of the constituents, in function of the loading direction. This methodology is validated for two different composite systems: a carbon epoxy cross-ply laminate and glass/polyester balanced angle-ply laminates.Finally, this numerical methodology is applied to two naval structures: a small section of a container ship and a flexible composite blade of a marine propeller. The two analyses obtain the failure mechanisms of both structures, as well as the ply or plies failing, and the corresponding constituent material causing the failure. One of the fatigue analyses is used in order to propose a simplified method capable of predicting the fatigue initiation in the structure, by only applying a quasi-static analysis. This method is based on comparing the maximum equivalent stress in the components with their SN fatigue curve.

Last update: 06/05/2021 05:06:02.