Author: GASPARINI, ANDREA
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING
Department: (DECA)
Mode: Article-based thesis
Deposit date: 21/01/2021
Reading date: 04/03/2021
Reading time: 11:00
Reading place: ETSECCPB - UPC Campus Nord - Videoconferència: https://meet.google.com/bfk-jhbi-qks
Thesis director: GRANDIA I BORRÀS, FIDEL | BRUNO I SALGOT, JORGE
Committee:
     PRESIDENT: VOLTATTORNI, NUNZIA
     SECRETARI: FOLCH DURAN, ARNAU
     VOCAL: MAZADIEGO MARTINEZ, LUIS FELIPE
Thesis abstract: CO2 geological storage is considered ane af the aptions technolagically viable in arder to decrease the industrial emissians of this gas species that strongly contribute to the greenhause effect in the atmosphere (IPCC, 2005). As naturally, oíl and gas am stored in poraus rocks that have the same key geological features required far CO2 starage, so CCS aim to recreate a naturnl · process to trap carban diaxide far millians of years into deep saline aquifer ar depleted oil c..nd gas fields. Episodic release of CO2 fram undergraund can occur from either natural processes (i.e., mantle degassing, thermal decarbonation, volcanic areas) o·r industrial (geological storagé of CO2, CCS). Because of leakage can occur at every step of a ces project, monitoring assumes an importan! role not only during and after injection but also befare in arder to know the state of the entire site from deep underground (reservoir level) to surface. In this respect, the use of atmospheric dispersion numerical models helps predicting the dispersion of the CO2-enriched gas plume once emitted from underground and allows an accurate map of risk leve! through time under particular meteorological conditions. The aim of this PhD. project is to give a better understanding of eo2 behaviour in the unsaturated zone and its atmospheric dispersion. The results are obtained from experimental and numerical modelling of CO2 leakage from an artificial leakage site and from natural analogues applied to risk assessment for CCS sites. To reach the above-mentioned targets and to prove results, this research plan combines experimental activity on site and numerical modelling. The first part ofthe research plan consisted of a contribution in the PISCO2 project at the ES.CO2 facilities placed in Ponferrada (Spain) . The objective of this project was to predict how the injected CO2 will move laterally and vertically in the unsaturated zone and to determine the critica! parameters that will affect the ecosystems. This part has been published in a peer review journal and presentad in an international congress.The second part of the PhD. project has focused on the study of two natural analogues in volcanic areas. Natural analogues provide evidences of the impact of CO2 leakage, for both sites two approaches have been followed: a) direct measurement of air concentration and b) numerical atmospheric modelling with the 1WODEE2 code. The study of eo2 emissions in natural systems provides a valuable information on the assessment and quantification of potential risks related to underground carbon storage leakage. Emissions of eo2 are studied in a iarge variety of geological environments, i.e., sedimentary basins, active andnon-active volcanic areas, seismically-active regions, and geothermal fields. Because of the physics of carbon dioxide gas, e.g., colourless, odourless, higher density compared to air, its accumulation may re:oult hazardous and even lethal for life The objective of atmospheric dispersion modelling is to predict how will move the plume, generated by a leakage in natural degassing systems and ces sitesResults obtained from this doctorate provide:¿Caupling experimental and numerical data in arder to test new methods and!or nume,ical codes;¿New elements to the knowledge of CO2 behaviours in the unsaturated zone as seen at PISCO2;¿Nev,¡ clues on nan-invasive monitoring techniques far ces sites and na ural ana!ogues;¿The usefulness of studying natural analogues;¿The usefuiness of the SAP system, as a good method to evaluate high gas emissions from underground;¿The efficiency of atmospheric modelling as a valuable methodology in the risk assessment;¿The importance of risk assessment maps in active degassing areas;¿ The need of production of forecasting maps to evaluate dangerous scenarios. Numerical models (multiphase transport and atmospheric gas dispersion) are proved to be usefull tools to predict gas behaviour in the vadose zone and in

Author: JAIMES BOTÍA, SAMUEL
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: 26/11/2020
Reading date: 04/03/2021
Reading time: 16:30
Reading place: Sala de Graus ETSAB - UPC Campus Sud - Av Diagonal 649 - videoconferència: meet.google.com/twb-xuus-tie
Thesis director: GUARDIA BASSOLS, MANUEL | RAMÍREZ NIETO, JORGE VICENTE
Committee:
     PRESIDENT: MUNTAÑOLA THORNBERG, JOSE
     SECRETARI: MONCLUS FRAGA, FRANCISCO-JAVIER
     VOCAL NO PRESENCIAL: DIAZ GUERRERO, RUTH MARCELA
Thesis abstract: The housing market designed in Bucaramanga during the study period of the fifties not only shows the transfer of technical knowledge through international cooperation, but also, the capitalist frenzy for the consumption of technology as a form of ideological containment, demonstrates the enthusiasm of entrepreneurs and industrialist through innovation and the development of new techniques and materials that express a new modernized lifestyle. Formal experimentalism in search of this ¿lifestyle¿ by local architects was more linked to the inter-institutional ¿corporate link¿ of particular interests in the exploration and yields of the construction of residential projects together with bureaucratic planning and foreign financing that was in search of accessibility of housing to the lower classes of workers and peasants which migrated to the city to reduce a real deficit, particularly the spatial changes of housing, in e.g... kitchens, sewing rooms, libraries, courtyards, interior gardens and exterior gardens, roads and urban public spaces, which gave distinction and exclusivity expressing the ¿social ascent¿ of the middle classes and the ¿progress¿ of an emerging business, industrial and commercial society of Bucaramanga residents. This ideological modernization of ¿great expectations of progress¿ is synthesized in the urban actions of Bucaramanga, the houses made in the foothills of the Sotomayor neighborhoods (Bolarquí); El Prado and Cabecera del Llano, for the emerging business, industrial and commercial society, the houses made in the small plateaus of the southern periphery in the neighborhoods of La Victoria, La Salle and Conucos for the working classes, and those made by self-construction in the archipelagos of the northern periphery and the western escarpment of the Arenales neighborhoods like, Kennedy , Las Olas, La Joya and Campo Hermoso of workers in order to contain the communist advance and moderately cover the housing deficit in Bucaramanga. The purpose of this thesis is a critical reflection of the inter-institutional cooperation and interests that determined the urban and architectural development of the Bucaramanga plateau, an academic contribution to the modernization of the city, that managed to recover the scattered and little valued information in missing files in order to take advantage of its knowledge in the reconstruction and to develop the ideas from the evidences found all though a deceptive but indispensable form of work for the understanding of today's metropolitan area of a contemporary city. Precisely, because this is it, the case of an intermediate city such as Bucaramanga, its contribution to possible comparative approximations is undeniable, it offers multiple references at the Latin American level, especially to OEA member states.

Author: BENVENISTE PEREZ, GABRIELA
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: 27/11/2020
Reading date: 05/03/2021
Reading time: 10:00
Reading place: Escola de Camins - UPC Campus Nord - videocofnerència: meet.google.com/mtk-zbzs-gye
Thesis director: AMANTE GARCIA, BEATRIZ | CORCHERO GARCIA, CRISTINA
Committee:
     PRESIDENT: RUIZ AMADOR, DIEGO
     SECRETARI: ÁLVAREZ DEL CASTILLO, MARÍA DOLORES
     VOCAL NO PRESENCIAL: FERREIRA FERREIRA, VICTOR JOSE
Thesis abstract: The continuous and expected increase of electrification in the transport sector, the so-called "electromobility" revolution, is one of the main drivers of progress in energy storage for vehicle propulsion.Today's electric vehicles (EVs) use lithium-ion (Li-ion) batteries due to their high energy density compared to other types of batteries. Current rechargeable lithium-ion (Li-ion) batteries for EVs are capable of storing around 180 Wh/kg of energy density at cell level and 120 Wh/kg at battery level, while the typical consumption of one kg of petrol produces 3350 Wh of useful work. There is still a factor of 19 between the energy delivered by a kilo of petrol and 1 kg of battery (for example, the autonomy of a car with a similar weight that is powered by batteries is 5-10 times less than with petrol). Therefore, if we want to reach, or even approach, the goal of a 500 km autonomy with battery powered vehicles in the short term, it is necessary to research new materials and battery configurations. In this respect, lithium-Sulphur (Li-S) batteries are the closest battery technology capable of meeting these expectations.Despite the fact that solutions exist at a technical level, or are in the process of being implemented, to overcome the technological barriers which electric energy storage presents for EVs, their implementation on our roads remains a challenge and is below the expectations setout. One of the reasons why this implementation is not satisfactory is the high cost of electric vehicles, mainly due to the high cost of batteries.New electric storage technologies such as Li-S batteries must therefore take into account not only the technical factor for their design, but also strategies to be able to reuse them in a second life in order to reduce their potential cost and thus help reduce the price of the EV paid by the end user. Furthermore, in addition to offering a suitable technological solution and presenting itself as an economically viable alternative, it is necessary to study the impact on the environment produced throughout the life cycle of Li-S batteries.For this reason, this doctoral thesis focuses on the environmental analysis of all the stages of the life cycle of these batteries, from the scaling of Li-S button cells produced in the laboratory to a 50 kWh battery. The methodology used to calculate the environmental impacts of the batteries is the Life Cycle Assessment (LCA) according to ISO 14040 and 14044:2006, which allows a quantitative evaluation of the environmental profile of the batteries for all the stages of their life cycle, emphasizing the most critical aspects that can be improved. In addition, the thesis has also dealt with issues related to the suitability of the batteries for use in second life, based on current experience with Li-ion batteries. To this end, on the one hand, ageing tests have been carried out on the cells to determine their behaviour and longevity. On the other hand, an economic evaluation has been made of the actions taken to dismantle a battery once its first life in the vehicle has ended, this being the first stage to prepare the battery for its second life in a secondary energy storage system.The results obtained from these analyses have served as a basis for establishing a framework for adding more information on the environmental performance of these batteries in Li-S. In addition, information has been provided in order to determine the feasibility of using this type of battery, not only in a first life in the electric vehicle, but also in its second life in a stationary application, and in this way to be able to follow the principles of the Circular Economy.

Author: GARCÍA PASTOR, 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 SIGNAL THEORY AND COMMUNICATIONS
Department: Department of Signal Theory and Communications (TSC)
Mode: Confidentiality
Deposit date: 03/02/2021
Reading date: 09/03/2021
Reading time: 14:00
Reading place: Aula Teleensenyament - B3 - ETSETB - Campus Nord - videoconferència: meet.google.com/frc-hbet-ydy
Thesis director: MATEU MATEU, JORDI | COLLADO GOMEZ, JUAN CARLOS
Committee:
     PRESIDENT: AIGNER, ROBERT
     SECRETARI: UBEDA FARRE, EDUARDO
     VOCAL NO PRESENCIAL: MIREA, TEONA
Thesis abstract: Nowadays, mobile devices have become a key technology in our lives, making us become part of a connected world, in which millions of mobile handsets are sold every year. In order to satisfy the user demands, many mobile communication standards are working together in the same device (LTE-A, 5G-NR, IEEE Wireless LAN Standards, etc.). High data rates are demanded for different wireless services working on a very crowded frequency spectrum, where all the devices and systems need to operate at the same time without detrimental of mutual interference. Although this major objective has to be faced from different perspectives, such as new modulations and new networking protocols, the radio frequency (RF) and microwave components, forming the communication chain in a transceiver, play a significant role on the whole system performance. Passive devices, like filters, contribute to the signal degradation due to passive intermodulation (PIM). PIM can be generated by the lack of mismatch between metallic contacts, oxidation, or basically, by the inherent nonlinear material properties used on the fabrication of the devices. Although the impact of PIM is lower than the distortion introduced by active devices, for current wireless services and their demanding requirements, any type of nonlinear generation is certainly an issue.Acoustic wave (AW) devices have become a fundamental technology for portable handsets supporting current wireless communication networks. Bulk Acoustic Wave (BAW) has become the main technology nowadays for high frequency filters. This technology allows a high degree of miniaturization, easily making more than 40 filters per device, and also gives other advantages as low insertion losses and multiple frequency operation. Despite these major advantages, BAW resonators exhibit a nonlinear behavior, i.e., they may suffer of intermodulation and harmonic distortion, which might become a real bottle neck for the full expansion of the technology in the ever increasing stringent requirements.The aim of this thesis is focused on characterizing this nonlinear limitation, quite present in acoustic resonators, by defining the origin of different nonlinear manifestations in BAW resonators, and providing new nonlinear models to reduce the computational time required to simulate those undesired effects.The first part of this work explains the basic knowledge about acoustic propagation and piezoelectricity, presenting the linear and nonlinear constitutive equations, including the typical nonlinear manifestations appearing in those devices. Then, the typical circuit models for AW devices and, more specifically its applicability to BAW devices, is presented.The second part of this work is focused on the nonlinear analysis of BAW resonators, by measuring different nonlinear manifestation of 8 different BAW devices, identifying the origin of the nonlinear effects and demonstrating that this unique hypothesis is consistent with those manifestations for all the measured resonators.

Author: HÜMBELI, PATRICK
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN PHOTONICS
Department: Institute of Photonic Sciences (ICFO)
Mode: Normal
Deposit date: 11/02/2021
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: ACÍN DAL MASCHIO, ANTONIO
Committee:
     PRESIDENT: VAN NIEUWENBURG, EVERT
     SECRETARI: GRASS, TOBIAS DANIEL
     VOCAL: DUNJKO, VEDRAN
Thesis abstract: Research at the intersection of machine learning (ML) and quan- tum physics is a recent growing field due to the enormous expec- tations and the success of both fields. ML is arguably one of the most promising technologies that has and will continue to dis- rupt many aspects of our lives. The way we do research is almost certainly no exception and ML, with its unprecedented ability to find hidden patterns in data, will be assisting future scientific discoveries. Quantum physics on the other side, even though it is sometimes not entirely intuitive, is one of the most successful physical theories and we are on the verge of adopting some quan- tum technologies in our daily life. Quantum many-body physics is a subfield of quantum physics where we study the collective behavior of particles or atoms and the emergence of phenomena that are due to this collective behavior, such as phases of matter. The study of phase transitions of these systems often requires some intuition of how we can quantify the order parameter of a phase. ML algorithms can imitate something similar to intu- ition by inferring knowledge from example data. They can, there- fore, discover patterns that are invisible to the human eye which makes them excellent candidates to study phase transitions. At the same time, quantum devices are known to be able to perform some computational task exponentially faster than classical com- puters and they are able to produce data patterns that are hard to simulate on classical computers. Therefore, there is the hope that ML algorithms run on quantum devices show an advantage over their classical analog. This thesis is devoted to study two different paths along the front lines of ML and quantum physics. On one side we study the use of neural networks (NN) to classify phases of mater in many-body quantum systems. On the other side, we study ML algorithms that run on quantum computers. The connection be- tween ML for quantum physics and quantum physics for ML in this thesis is an emerging subfield in ML, the interpretability of learning algorithms. A crucial ingredient in the study of phase transitions with NNs is a better understanding of the predictions of the NN, to eventually infer a model of the quantum system and interpretability can assist us in this endeavor. The interpretabil- ity method that we study analyzes the influence of the training points on a test prediction and it depends on the curvature of the NN loss landscape. This further inspired an in-depth study of the loss of quantum machine learning (QML) applications which we as well will discuss. In this thesis we give answers to the questions of how we can leverage NNs to classify phases of matter and we use a method that allows to do domain adaptation to transfer the learned "in- tuition" from systems without noise onto systems with noise. To map the phase diagram of quantum many-body systems in a fully unsupervised manner, we study a method known from anomaly detection that allows us to reduce the human input to a mini- mum. We will as well use interpretability methods to study NNs that are trained to distinguish phases of matter to understand if the NNs are learning something similar to an order parame- ter and if their way of learning can be made more accessible to humans. And finally, inspired by the interpretability of classical NNs, we develop tools to study the loss landscapes of variational quantum circuits to identify possible differences between classi- cal and quantum ML algorithms that might be leveraged for a quantum advantage.