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: MOURA BERODIA, JOSE LUIS
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.

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.

Author: MUÑOZ MARTIN, JOAN FRANCESC
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
Department: Department of Signal Theory and Communications (TSC)
Mode: Normal
Deposit date: 07/05/2021
Reading date: 17/06/2021
Reading time: 16:00
Reading place: Aula Teleensenyament - B3 - ETSETB - Campus Nord - meet.google.com/kkh-phaj-kdt
Thesis director: CAMPS CARMONA, ADRIANO JOSE
Committee:
     PRESIDENT: WICKERT, JENS
     SECRETARI: LOPEZ MARTINEZ, CARLOS
     VOCAL NO PRESENCIAL: RODRÍGUEZ ÁLVAREZ, NEREIDA
Thesis abstract: Earth Observation using satellites has helped to better model our planet. The goal of such systems is to provide large data sets to help to understand the effects of our actions on the climate, to predict storms in near real-time, to prevent forest fires, or to prevent desertification, among others. In the last years, thanks to the miniaturization of electronics a new type of satellite have become popular, the CubeSat, a small spacecraft weighing from 1 to 10 kg, which can carry different types of instruments. Thanks to the cost reduction of these new platforms, new techniques can be easily evaluated, and the concept of a mesh of sensors surrounding the Earth is becoming a reality. Besides, the suitability of new techniques is being proven for such small spacecraft, such as GNSS reflectometry (GNSS-R). GNSS-R instruments are typically cheaper, more efficient (in terms of power consumption), and smaller than their traditional equivalent ones. This Ph.D. thesis is devoted to the development of passive microwave remote sensing instruments for CubeSats. However, before entering into the instrument design, several field experiments were proposed to model and validate the use of GNSS-R under different conditions. This Ph.D. thesis is divided into three main parts. The first part is devoted to assessing the capabilities of GNSS-R to retrieve different geophysical parameters through a different set of field experiments. First, the achievable spatial resolution of L1 and L5 GNSS-R signals is analyzed under different conditions. Second, taking into account the incoherent integration limits previously analyzed, the coherency of GNSS-R signals is analyzed at L1 and L5 bands. Third, thanks to the use of short integration times, multiple reflections received in the GPS L5 reflected signal could be identified as multiple peaks, thanks to the narrower auto-correlation function of such signals. Over the ocean, these multiple peaks are analyzed and linked to the sea state. Over the Australian rainforest, these multiple peaks at L5 are linked to multiple reflections on top of the vegetation canopy and in the bare soil. Fourth, a methodology to estimate soil moisture content over land using GNSS-R signals is proposed. Finally, the use of GNSS-R signals to estimate sea-ice thickness and snow content over the sea-ice is examined thanks to the data collected by a circular polarization GNSS-R instrument part of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The second part of this dissertation is devoted to the design, implementation, and test of three passive microwave instruments for CubeSats. First, the Flexible Microwave Payload -1 (FMPL-1) is proposed as part of the 3Cat-4 mission. The instrument includes three experiments in a single platform: a total power L-band radiometer with frequent internal calibration, an L1/L2 GNSS reflectometer, and an AIS receiver. Second, the FMPL-2 instrument is proposed as the main payload of the 3Cat-5/A, one of the two instruments composing the ESA FSSCat mission, the first third-party mission contributing to the Copernicus system based on CubeSats. This second instrument is the evolved version of FMPL-1 and can provide synchronous GNSS-R and L-band radiometry data. Finally, a third instrument, the FMPL-3, is proposed for the GNSSaS mission of the NSSTC from the UAE. This third instrument includes the first-ever GNSS-R receiver at L5 and aims to prove the capabilities of such signals from space. Finally, in the third part, the first results of FMPL-2 are presented and analyzed. The instrument was successfully launched into a Low Earth Orbit during the Vega VV16 flight. First, the results of FMPL-2 during the first two weeks of in-orbit validation are presented. Data-driven algorithms to estimate sea-ice concentration, thickness, and soil moisture content over land are implemented using L-band microwave radiometry data and GNSS-R data retrieved by FMPL-2.

Author: YANG, XUEFEI
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: 20/05/2021
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: LOPEZ GRIMAU, VICTOR | CRESPI ROSELL, MARTIN
Committee:
     PRESIDENT: BACARDIT DALMASES, ANNA
     SECRETARI: GUTIERREZ BOUZAN, M. DEL CARMEN
     VOCAL: BOSCH SUADES, CARME
Thesis abstract: Textile wastewater often shows high color concentration, containing a large range of organic chemicals, with high chemical oxygen demand as well as hard-degradation materials. Therefore, understanding and developing effective textile industrial wastewater treatment technologies is environmentally important. Different treatments such as biological or physico-chemical processes have been studied to treat textile wastewater.Membrane Bioreactor (MBR) technology has been widely applied in textile wastewater treatment and Moving Bed Biofilm Reactor (MBBR) is a relatively novel technology to treat this type of wastewater. Both of them have some deficiencies and limitations during application. Thus, a MBBR-MBR hybrid system could be an attractive solution to the shortcomings of each treatment process.In this thesis, a hybrid MBBR-MBR system has been designed and applied for the treatment of textile wastewater. Additionally, the feasibility of reusing the treated water in new dyeing processes has been studied.The first step of the thesis work has been the comparative study of the treatment of textile wastewater by three treatment processes, conventional activated sludge (CAS), MBR and MBBR, working under the same operating conditions. The results showed that technically, MBR was the most efficient technology, of which the chemical oxygen demand (COD), total suspended solids (TSS), and color removal efficiency were 91%, 99.4%, and 80%, respectively, with a hydraulic retention time (HRT) of 1.3 days. MBBR, on the other hand, had a similar COD removal performance compared with CAS (82% vs. 83%) with halved HRT (1 day vs. 2 days) and 73% of TSS removed, while CAS had 66%. Economically, MBBR was a more attractive option for an industrial-scale plant since it saved 68.4% of the Capital Expenditures (CAPEX) and had the same Operational Expenditures (OPEX) as MBR. The MBBR system also had lower environmental impacts compared with CAS and MBR processes, since it reduced the consumption of electricity and decolorizing agent with respect to CAS. According to the results, the water treated by the MBBR system was reused to make new dyeings and the quality of new dyed fabrics was within the acceptable limits of the textile industry.Combined with the theory and experimental results, a hybrid MBBR-MBR reactor was designed and applied in textile wastewater treatment. The MBBR-MBR system achieved reducing the HRT to 1 day, which is very promising in textile industry comparing with conventional biological treatment. The removal efficiency of COD reached 93%, which is almost the maximum for a biological process treating this type of wastewater, as well as the color removal performance, which achieved 85%. Additionally, 99% of the TSS were removed due to the filtration. Furthermore, new dyeing processes reusing the treated water were performed. Color differences between new dyed fabrics and reference fabrics were found within the general requirement of textile industry (DECMC(2:1) < 1).Additionally, based on the experimental results in the pilot plant, an economic study and LCA analysis were carried out to evaluate the economic and environmental feasibility of the implementation of the hybrid MBBR-MBR on an industrial scale. Economically, MBBR-MBR had lower CAPEX and OPEX than CAS process due to lower effluent discharge tax and the decolorizing agent saved. The result of Net Present Value (NPV) and the Internal Rate of Return (IRR) of 18% suggested that MBBR-MBR is financially applicable for the implantation into industrial scale. The MBBR-MBR system also had lower environmental impacts compared with CAS process in the LCA study, especially in some categories, such as the Climate change, Human Health, Marine eutrophication, and ecotoxicity categories, thanks to the high quality of the effluent treated by MBBR-MBR and the avoiding of using extra decolorizing agent, a compound based on a quaternary amine.

Author: CALVO MINGUILLON, AUSIAS MARCH
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: 21/05/2021
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: GUARDIA MANUEL, ELVIRA
Committee:
     PRESIDENT: MADURGA DÍEZ, SERGIO
     SECRETARI: MARTÍ RABASSA, JORDI
     VOCAL: CALERO BORRALLO, CARLOS
Thesis abstract: The underlying topic of this thesis is the study of the application of the Force Matching (FM) algorithm to parameterize ion-water Force Fields using ab-initio simulations as reference. In order to do so three different main steps have been followed:(I) The results of a set of Car-Parrinello Molecular Dynamics (CPMD) simulations consistent of one ion and 96 water molecules have been analyzed and described to be used as reference for the FM algorithm and for the subsequent assessment of the obtained results. Four monovalent anions (fluoride, chloride, bromide and iodine), three monovalent cations (lithium, sodium and potassium) and two divalent cations (magnesium and calcium) have been used. For each simulation both, structural and dynamical properties, such as the ion-water Radial Distribution Functions (RDF), the coordination numbers, the residence time, the ion self-diffusion coefficient have been computed. The dynamics of the solvation shell molecules has also been analyzed.(II) To try to reduce the effects of the dimensionality reduction when moving from Density Functional Theory simulations to classical ones the use of polarization is one of the first techniques that is usually considered. In order to move a step forward in this direction the use of damping functions in conjunction with Polarizable Point Dipoles has been tested. For the chloride ion two different screening functions, Gaussian and exponential, were tested with three different values of ion polarizability of 2.25 ų, 4.00 ų and 5.48 ų and were then compared to the use of an undamped polarizability of 3.25 ų and to the results from the CPMD simulations. Both damping functions performed well when compared to the CPMD results and allow a better reproduction of dynamical properties of the ion and of its solvation shell at a negligible computational cost.(III) The main part of this thesis has consisted in testing and evaluating the performance of a wide set of ion-water interaction schemes in order to validate their capacity to reproduce the ab-initio results by means of the FM process. All the fitted force fields are of the form of a Lennard Jones potential. Three different water models have been mainly used. The well known SPC/E and RPOL models and a set of SPC-like water models previously developed in our group using the FM process referenced in this work as SPC-FM. Two different dispersion damping functions have been used: the Tang-Toennies function and a Fermi like one. Finally, the scaling of the ion charges and the use of weights during the matching process has been tested as well. The resulting fitted potentials have been used in a series of classical Molecular Dynamics simulations of ion-water systems at the same conditions as those of the CPMD simulations. Despite having a wide range of physical properties computed from the reference CPMD simulations, to keep the comparison simple enough, the quality of the force matching potentials has been assessed by comparing the resulting ion-water forces and the ion-oxygen and ion-hydrogen RDFs of the fitted potentials to those of reference. For each ion the best combination of water model, damping, scaling and force weight has been determined.