Doctoral School

Reading date: 21/11/2024

• ARFELIS ESPINOSA, SERGI: Life cycle assessment as a tool for the industrialisation of chemical and mechanochemical processes
  
  Author: ARFELIS ESPINOSA, SERGI
  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: Department of Civil and Environmental Engineering (DECA)
  Mode: Article-based thesis
  Deposit date: 27/09/2024
  Reading date: 21/11/2024
  Reading time: 13:00
  Reading place: Defensa pública lloc ETSECCPB UPC, Campus Nord Building C1. Classroom: 002 C/Jordi Girona, 1-3 08034 Barcelona
  Thesis director: FULLANA PALMER, PERE | BALA GALA, ALBA | MALPARTIDA GARCIA, IRENE
  Committee:
       PRESIDENT: MAIRELES, PEDRO JESÚS
       SECRETARI: DELGADO AGUILAR, MARC
       VOCAL: CANALES MUÑOZ, ROBERTO IVAN
  Thesis abstract: The chemical sector is a $4 trillion global business and a major employer, with chemicals present in almost all manufactured products. Increasing investment and the chemical industry's innovative capacity to provide safe and sustainable products will be vital in offering new solutions and supporting the ecological transition of our economy and society. Multiple approaches and tools have been developed to assist chemists in the development, design, and application of chemical products. The Life Cycle Assessment (LCA) approach, applied to the design of chemicals and processes, has helped scientists examine environmental impacts from a life cycle perspective. It provides a global view of environmental burdens, covering a broad set of environmental indicators such as Global Warming, Primary Energy Consumption, Water Use, Land Use, or Resource Depletion.This thesis is related to the application of LCA to the industrialization of chemical and mechanochemical processes. The first article presents a literature review of LCA for chemical processes. The second article is another review on mechanochemical processes. Chemistry and mechanochemistry are leading sectors in the application of LCA, but their methodology is still scarce. The development of these articles aims to provide a guide for the advancement of these topics. Additionally, the thesis continues with the evaluation of innovative technologies for chemical processes: production of calcium zincate as an ingredient for rechargeable batteries, cellulose extraction from wood chips, or nicotine extraction from tobacco leaves, for instance.It has been concluded that the choice of raw material is often the main source of environmental impact in a chemical process. Furthermore, mass and energy balances, as well as the type of energy supplied to power the process, are of great importance as part of the life cycle inventory. When selecting the functional unit (FU) for industrial chemical processes, where a given amount of product must be supplied within a given time frame, special attention must be paid. Although it falls outside the scope of cradle-to-gate LCA practice, variables such as reaction residence time can result in the final product having more service units or more functions. Therefore, this should be considered valuable additional information when deciding between alternatives. The LCA result with an FU that depends solely on mass does not account for this. Several chemical LCA studies already conduct assessments using flow rate as an FU. Another example is the consideration of module D within EN 15804:2012+A2:2019 for the inclusion of information outside the cradle-to-gate scope in LCAs of construction products.Moreover, the scalability of material flows from the laboratory scale, where data is obtained, to the pilot or industrial scale, where the process will be applied, is of crucial importance. For this purpose, different frameworks based on thermodynamic equations, as well as process modeling and simulation tools, have been used throughout the thesis. For instance, it has been observed that energy optimization from the lab to the industrial scale is around 20% on average, reaching maximum values of 90% for some equipment, such as the reactor used in Deasyl's laboratories. Finally, in LCA comparisons, an environmental impact evolution study is conducted, taking into account forecasts for electricity mixes in the coming years according to reports from the European Green Deal to interpret how the results will behave in the future.
  

• BANDAHALLI MALLAPPA, PRASAD KUMAR: Design and Implementation of High-Level Multilevel Inverters: Focusing on 15-level, 25-level, and 33-level Topologies with Asymmetrical Configuration and Optimal Component Choices
  
  Author: BANDAHALLI MALLAPPA, PRASAD KUMAR
  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: 27/09/2024
  Reading date: 21/11/2024
  Reading time: 11:30
  Reading place: Sala Polivalente A0.03. Planta 0. Edificio "A" de la EEBE del Campus Diagonal-Besòs.
  Thesis director: MARTINEZ GARCIA, HERMINIO | VELASCO QUESADA, GUILLERMO
  Committee:
       PRESIDENT: BARGALLO PERPIÑA, RAMON
       SECRETARI: VIDAL IDIARTE, ENRIQUE
       VOCAL: FERNÁNDEZ HERRERO, CRISTINA
  Thesis abstract: The primary goal of this thesis is to establish multilevel inverter (MLI) topologies for industrial settings. Because of its numerous benefits, including low power dissipation on powersupplies and low harmonic contents, MLI topologies are utilized in medium- and high-power applications, such as active power filters, FACTS devices, and machine currents. The chosenswitching strategies are crucial in removing harmonic distortion from the output voltage provided by the MLI. Depending on the inverter's power requirements, different topologies and controlstrategies may be selected. However, they have several drawbacks over MLI, such as the need for separate power sources for each stage. Consequently, MATLAB/SIMULINK is used to simulateMLI.This work aims to offer a unique topology for a single-phase 15-level asymmetric MLI to minimize component requirements. The suggested design uses asymmetric DC sources to reach amaximum 15-level output voltage through an H-bridge topology. To enable a 25-level version appropriate for renewable energy applications, the original 15-level MLI structure is furtherimproved, lowering system costs and dimensions. However, the higher component count in MLI presents reliability issues, particularly about the decrease of total harmonic distortion, whichcontinues to be a research focus. Several factors are examined for the proposed 15-level- and the extended 25-level MLI, including total standing voltage, multilayer inverter cost function, andpower loss. Next, it facilitates the integration of renewable energy sources and streamlines the use of components by contributing to a novel topology for 15-level asymmetric MLI. Even thoughmultilevel inverters have many benefits, future developments in this field must address reliability issues related to overall harmonic distortion reduction. Then, a unique 33-level asymmetricalsingle-phase MLI is built, utilizing fewer components and a lower Total Standing Voltage (TSV) at the switches. Variable-rated switches are employed to lower the overall cost of the inverter, andthe distribution of stress among the switches is carefully examined. The suggested design combines four asymmetrical DC sources with twelve switches to generate 33 voltage output levels.The inverter's performance is determined by many crucial factors, including TSV, efficiency, power loss, and cost function (CF). Using a range of combinational loads, the MLI was evaluatedin dynamic load conditions with unforeseen load disturbances, and it was discovered to be stable throughout the operation. A thorough comparison uses graphical representations based on stressvi across switches, stress distribution, switch count, DC source count, gate driver circuits, component count factor, TSV, CF, and other existing topologies. It is demonstrated to be more efficient andbetter in every way. According to simulation and experiments, the Total Harmonic Distortion (THD) is within IEEE guidelines. The suggested framework was created in MATLAB/Simulinkand tested using hardware in a lab environment.
  

• SIMONA PUJADÓ, JOSEP: A proposal for a new method to assess road traffic noise in the United Kingdom
  
  Author: SIMONA PUJADÓ, JOSEP
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN NATURAL RESOURCES AND THE ENVIRONMENT
  Department: Department of Mining, Industrial and ICT Engineering (EMIT)
  Mode: Normal
  Deposit date: 29/07/2024
  Reading date: 21/11/2024
  Reading time: 12:00
  Reading place: Sala d'Actes EPSEM
  Thesis director: VALLBE MUMBRU, MARC | ROSSELL GARRIGA, JOSEP MARIA
  Committee:
       PRESIDENT NO PRESENCIAL: TORIJA MARTÍNEZ, ANTONIO
       SECRETARI: JORGE SANCHEZ, JUAN
       VOCAL NO PRESENCIAL: AUSEJO PRIETO, MIGUEL
  Thesis abstract: This thesis proposes a novel approach for assessing road traffic noise in the United Kingdom, aiming to partially revise the existing methodology outlined in the Design Manual for Roads and Bridges (DMRB). This assessment transcends the mandates of planning law and policy, encompassing obligations imposed by both common law and environmental legislation.The document re-examines the legal and regulatory stipulations that noise assessments must satisfy. It offers a thorough and lucid examination of the progression of noise legislation in England, tracing the history of rail, road, and aircraft noise from their inception to the present.Upon establishing the legal and regulatory prerequisites, the thesis conducts a critical analysis of the prevailing planning policies concerning noise, considering factors such as sustainability and good design principles. Subsequently, it scrutinises the methodology currently prescribed in the DMRB.The thesis then delves into cost-benefit analysis, exploring its application in evaluating road traffic noise and the implementation of noise abatement strategies. With this groundwork in place, it introduces a proposition to modify the existing DMRB methodology.The proposed amendments encompass four key aspects:1. Expanding the reporting of impacts to include both individual receptors and the wider community, thereby addressing the stipulations of common and environmental law.2. Shifting the focus from reporting ‘impacts’ to reporting ‘effects’.3. Elucidating the cost-benefit analysis involved in the adoption of noise reduction measures.4. Assigning a monetary value to noise effects, which could serve as an indicator of a project’s significance.This refined approach aims to enhance the framework for noise assessment, ensuring a more holistic and effective evaluation of road traffic noise implications.Furthermore, the research presented in this thesis investigates the factors that must be considered in any proposal that contemplates replacing the current road traffic noise prediction methodology (CRTN) with a new method based on the Harmonoise European research project. It specifically focuses on the decision-making process regarding the introduction of a noise mitigation measure (where a noise fence is taken as an example of one of such mitigation measures). This decision-making process should include not only the cost of the mitigation measure but also the cost of any compensation to be paid for the loss of value in an interest of land under the Land Compensation Act 1973.
  

Reading date: 22/11/2024

• BALLESTAR DE LAS HERAS, RICARDO LUIS: Manufacturing and recycling of polyolefins and biopolymers in a circular economy model. Mechanical, thermal and morphological characterization of polymers and high-performance films.
  
  Author: BALLESTAR DE LAS HERAS, RICARDO LUIS
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN POLYMERS AND BIOPOLYMERS
  Department: Department of Chemical Engineering (EQ)
  Mode: Article-based thesis
  Deposit date: 26/07/2024
  Reading date: 22/11/2024
  Reading time: 16:00
  Reading place: Defensa pública a ESEIAAT (Escola Superior d'Enginyeries Industrial, Aeroespacial i Audiovisual de Terrassa) Edifici TR1. C. Colom, 1 08222 Terrassa
  Thesis director: COLOM FAJULA, XAVIER | CAÑAVATE AVILA, FRANCISCO JAVIER
  Committee:
       PRESIDENT: SAURINA CANALS, JOAN
       SECRETARI: GARRIGA SOLE, PERE
       VOCAL: MARÍN GENESCÀ, MARC
  Thesis abstract: On April 29th, 2015, the EU enacted Directive 2015/720, aimed at reducing plastic consumption, promoting the use of reusable bags and encouraging the replacement of single-use plastic bags with biodegradable alternatives. This European legislation was transposed into Spanish law by Royal Decree 293/2018, dated May 18th.This legislation and its accompanying regulations have significantly impacted the transformation sector, forcing it to reinvent itself to continue its activities. This work aims to provide answers to the challenges faced by manufacturers due to this new context, as well as address the needs resulting from it. Distinctive features of this project are its practical nature and industrial scale.A primary objective is to establish the processability and quality windows for recycled post-industrial and post-consumer materials, ensuring the production of a final product with predefined quality standards. The study examines three types of polyethylene: virgin, post-industrial, and post-consumer. Each type undergoes a combined cycle simulating an industrial recycling process, with post-industrial material being processed up to twelve times and post-consumer material up to four times. This methodology of cyclic processing supports the principle of circularity in sample characterization.For each cycle, involving extrusion and recycling, the study examines micro and macroscopic changes, analyzing morphological and structural changes (using DSC, TGA, GPC, and FTIR techniques) and the evolution of mechanical properties (tensile strength, elongation at break, tear resistance, impact resistance (dart test), and colorimetric changes).At the microstructural level, two types of crystalline structures are observed, and they evolve differently through the processing cycles due to the thermo-oxidative degradation phenomena that occur along the process. The changes include a reduction in crystallinity due to the breakdown of more linear and less branched chains, and an increase in cross-linking among more branched structures. These microstructural changes affect post-industrial and post-consumer recycled polyethylene differently.Macroscopically, tear resistance is the most critical property affected during the recycling cycles, decreasing by up to 40% from the initial value and potentially becoming the main limitation for the successive reuse of these polymers.In line with the previously mentioned regulations, biodegradable polymers are another focus of interest. The study examines biodegradable compostable polymers used to manufacture single-use bags. A secondary objective is to determine how long these biodegradable polymers retain their usability properties under standard storage conditions, analyzing the samples over twelve consecutive months.Macroscopically, a progressive loss in tensile, elongation, and impact properties is the most significant phenomenon. Microscopically, two degradation mechanisms—hydrolysis and thermo-oxidation—are observed, both occurring in the amorphous phase of the material.The study concludes that the tested bags have a shelf life of over twelve months under standard storage conditions.
  

• BARRIOS AVALOS, JUAN JOSE: Reestructuración urbana de la Región Hidrológica 36 Nazas - Aguanaval, México: Modelos agroproductivos y sus sistemas hidrográficos
  
  Author: BARRIOS AVALOS, JUAN JOSE
  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 URBANISM
  Department: Department of Urbanism, Territory and Landscape (DUTP)
  Mode: Normal
  Deposit date: 30/09/2024
  Reading date: 22/11/2024
  Reading time: 11:30
  Reading place: Face-to-face (Room C-B1. ETSAB. Main floor)
  Thesis director: FRANQUESA SANCHEZ, JORDI
  Committee:
       PRESIDENT: LLOP TORNE, CARLOS JUAN
       SECRETARI: MENDOZA ARROYO, MARIA DEL CARMEN
       VOCAL: SAINZ GUTIERREZ, VICTORIANO
  Thesis abstract: Hydrological Region 36 (RH36) is one of the 37 hydrological regions identified in Mexico by the National Water Commission. Within this region lie the basins of the Nazas and Aguanaval rivers, two endorheic rivers in northwestern Mexico. The waters of these rivers have enabled the Metropolitan Area of La Laguna to become a prosperous region with a significant agro-industrial sector. This success was achieved through the regulation of the rivers, primarily the Nazas River, via the construction of dams and canals between 1930 and 1990. However, the control established over the Nazas River through the Lázaro Cárdenas and Francisco Zarco dams, as well as the network of canals in the lower basin, exacerbated the loss of the Mayrán Lagoon at its mouth and led to the disappearance of flow in the lower basin in the area of Torreón, Gómez Palacio, and Lerdo.In the lower basins of RH36, there is significant water stress resulting from the overexploitation of major aquifers and the reduced availability of water resources due to the impacts of climate change. This research is based on the hypothesis that the severe water stress is partly caused by the disconnection between the regional infrastructure for water storage and distribution, agricultural irrigation systems, rural and urban populations, and their productive agricultural areas. Additionally, it is argued that hydraulic infrastructures have been planned without considering the regional urban context of the lower basin and its logical dimensions, leading to disruptions in the ecological matrix and the organization of rural populations.The research employs a basin approach to define the scope of the study. It sustained that for the restructuring of populations and the potential fluvial restoration of the Nazas and Aguanaval rivers, it is essential to understand the organization of all communities within the geographical boundaries. Each of the 33 sub-basins that make up RH36 are subject to an in-depth analysis of its urban and rural fabric. In addition to populations, the study of agricultural areas, hydraulic infrastructure, and road networks is a fundamental part of this basin approach.The thesis is organized into four chapters. The first chapter outlines the methodology, hypothesis, objectives, and the general structure of RH36. It also includes references to water storage structures in various contexts with geographical conditions similar to RH36. The second chapter is an atlas aimed at constructing morphological information about the 33 sub-basins of the region, including their urban, rural, and agricultural areas. This atlas is one of the main contributions of the research and serves as a prelude to Chapters III and IV. Chapter III explores global references on river restoration and dam removal, which serve as a foundation for Chapter IV, where the strategic approach to fluvial restoration in RH36 is presented.Finally, the research presents conclusions based on a thorough analysis of the urban and rural fabric, the hydrographic network, and hydraulic infrastructure. It argues that hydraulic infrastructures located in the urban-rural transition zones of intermediate cities within RH36 can provide ecosystem services and promote ecological and productive balance in the region. Furthermore, it maintains that the hydrological restoration in the lower courses of the Nazas and Aguanaval rivers is directly dependent on the restructuring of hydraulic infrastructure in both urban and rural populations throughout Hydrological Region 36.