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Ítem A Class of Conservative Lagrangian-Eulerian Methods on Triangular Grids for Hyperbolic Problems : Design, Analysis and Applications(Universidad EAFIT, 2024) Agudelo Quiceno, Jorge Eliécer; Pérez Sepúlveda, John Alexander; Cano Sánchez, José AlbeiroIn this thesis, we construct, analyze and implement a class of fully-discrete and semi-discrete schemes on triangular grids intended to numerically solve initial value problems involving multidimensional hyperbolic conservation and balance laws, both scalar and systems. The construction of this novel class of schemes is based on the no-flow surface/curve concept and introduces an effective class of numerical fluxes that do not require constructing or evaluating the Jacobian matrix of the respective flux functions. The implementation of the new fully-discrete and semi-discrete Lagrangian-Eulerian schemes, , in the solution of nontrivial scalar and systems problems, is performed using a weak CFL-type stability condition that is independent of the eigenvalues (exact and approximate values) of the relevant Jacobian of the numerical flux functions, and without the need for high-resolution reconstruction procedures.Ítem A Novel Injectable Piezoelectric Hydrogel for Periodontal Disease Treatment.(Universidad EAFIT, 2023) Roldán Lopera, Lina María; Correa Vélez, Santiago AlbertoPeriodontal disease is a multifactorial, bacterially induced inflammatory condition characterized by the progressive destruction of periodontal tissues. The successful nonsurgical treatment of periodontitis requires multifunctional technologies offering antibacterial therapies and promotion of bone regeneration simultaneously. For the first time, in this study, an injectable piezoelectric hydrogel (PiezoGEL) was developed after combining gelatin methacryloyl (GelMA) with biocompatible piezoelectric fillers of barium titanate (BTO) that produce electrical charges when stimulated by biomechanical vibrations (e.g., mastication, movements). We harnessed the benefits of hydrogels (injectable, light curable, conforms to pocket spaces, biocompatible) with the bioactive effects of piezoelectric charges. A thorough biomaterial characterization confirmed piezoelectric fillers' successful integration with the hydrogel, photopolymerizability, injectability for clinical use, and electrical charge generation to enable bioactive effects (antibacterial and bone tissue regeneration). PiezoGEL showed significant reductions in pathogenic biofilm biomass (∼41%), metabolic activity (∼75%), and the number of viable cells (∼2-3 log) compared to hydrogels without BTO fillers in vitro. Molecular analysis related the antibacterial effects to be associated with reduced cell adhesion (downregulation of porP and fimA) and increased oxidative stress (upregulation of oxyR) genes. Moreover, PiezoGEL significantly enhanced bone marrow stem cell (BMSC) viability and osteogenic differentiation by upregulating RUNX2, COL1A1, and ALP. In vivo, PiezoGEL effectively reduced periodontal inflammation and increased bone tissue regeneration compared to control groups in a mice model. Findings from this study suggest PiezoGEL to be a promising and novel therapeutic candidate for the treatment of periodontal disease nonsurgically.Ítem Aide à la décision en conception préliminaire par l'estimation des impacts environnementaux(Universidad EAFIT, 2016) Agudelo Gutiérrez, Lina María; Mejía Gutiérrez, Ricardo; Nadeau, Jean Pierre; Pailhes, JérômeÍtem Analyses of the Morphometric Variation within Caiman crocodilus Species Complex in Colombia(Universidad EAFIT, 2022) Angulo-Bedoya, Mónica; Webster, Mark; Benítez, Hugo A.; Balaguera-Reina, Sergio; Correa, Santiago; Roberto, Igor J.; Moncada-Jimenez, Juan F.; Mazzotti, Frank J.; Espinoza-Donoso, Sebastian; Lemic, Darija; Correa Vélez, Santiago Alberto; Pinel Peláez, NicolásÍtem Analysis of the environmental licensing procedure for coastal environments in Colombia : a geomorphological perspective from the concept of susceptibility to the effect of human interventions(Universidad EAFIT, 2019) Pereira Pomárico, Cristina Isabel; Correa Arango, Iván DaríoImportant flaws in the environmental licensing procedures in Colombia are directly related to the generalized degradation of its coastal fringes and littoral zones. These areas are severely affected by human interventions that interfere with natural processes and severely modify their sedimentary balances, geomorphological contexts, and physical-biotic conditions. Among many other examples, the following stand out: a) the widespread erosion and destruction of beaches and dunes in the Magdalena River delta, associated with the construction of the Bocas de Ceniza jetties; b) the drastic modification of the hydrodynamics of the littorals at the Atlantic and Magdalena departments due to linear infrastructure projects; c) the hyper-salinization and loss of more than 30,000 hectares of mangrove in the lagoon complex of the Ciénaga Grande de Santa Marta (CGSM) due to the expansion of the agricultural frontier and linear infrastructure projects; d) the accelerated retreat of beaches and cliffs in the southern Caribbean, due to activities such as deforestation, beach material extraction, and disordered and chaotic construction of nearly 500 rigid shore protection works; and e) the salinization of more than 10,000 hectares of freshwater marshes in the Bay of Cispatá as a consequence of the induced formation of the new delta of Tinajones. In this sense, the location of infrastructure in geological and geomorphologically unstable lands, affected by phenomena such as coastal subsidence and mud diapirism, poses first order natural threats and risks. This is a palpable panorama in the present and future of urban and rural areas of cities such as Barranquilla, Cartagena, Arboletes and Necoclí, all of them with future developments (industry, ports, urban development) of the greatest importance. The environmental costs associated with such interventions are incalculable, not counting the existence of numerous other examples, which demonstrate among other factors an insufficient acknowledgment to geomorphology in the evaluation, monitoring, and control of human interventions in the marine-coastal environment. These environmental management functions in Colombia are provided through the environmental licensing procedure, which rests upon national and regional authorities according to Law 99 of 1993. In the above context, the following research questions arise: What elements of the environmental licensing of interventions in coastal environments can be improved, giving priority to the particular geomorphological contexts of the intervention zones? How has the regulatory system evolved in Colombia with respect to human interventions on coastal environments? What technical improvements can be made to the Colombian regulatory framework to guide the evaluation, monitoring, and control of human interventions from the geomorphological approach of susceptibility? This research work examines the environmental regulatory framework that currently governs Colombian coastal zones, through two geographic levels. At the first macro level, human interventions 16 are characterized and analyzed on the continental Caribbean coast, a region that represents a significant sample of the Colombian context due to its higher levels of human occupation and consequent anthropogenic disturbances. At a second level, in greater detail, the conceptual and methodological approach resulting from this research is defined and illustrated, with the demonstration in one of the coastal environmental units defined by decree 1120 of 2013 for integrated coastal management. To answer the questions raised, Chapter I briefly introduces the historical geomorphological evolution of the Colombian coastlines since the end of the XVIII century. The complex geology and geomorphology of the Caribbean and Pacific coasts of Colombia are evident in this "appetizer", in which low-relief deltaic islands and mangroves contrast with steep rocky reliefs, cliffs and wide emerged and submerged coastal platforms. The historical evolution of the Colombian littorals involves changes in the coastline estimated in hundreds of meters, at maximum rates of 40 meters a year (Punta Rey, Arboletes, Tumaco Bay), and land losses and gains of the order of tens of square kilometers (Ciénaga de Mallorquín, Isla Cascajo, Tinajorenas Delta - Cispatá, Bay, Urabá Gulf, San Juan and Patía river deltas). These cases reflect drastic variations in the sediment balances of the coast, many of them caused or heavily influenced by human actions, such as navigation infrastructure, modification of river courses and coastal protection works. Chapter II identifies the geomorphological perspective in the environmental licensing of coastal interventions in Colombia, based on its comparison with the regulatory frameworks of Italy, Spain, and Cuba. The interviews and documentary reviews highlighted 59 interventions associated with human uses and activities in the coastal zones, whose compulsory nature for the licensing varies among countries. The natural geomorphological processes were also analyzed within the technical criteria included in the official guidelines for environmental studies. It is concluded that, despite the worldwide acceptance of environmental impact assessments through a licensing procedure, their application in coastal environments is still very diverse and limited in terms of the pertinence of the geomorphological processes that configures the coast. Therefore, seven good practices for the evaluation and control of anthropogenic impacts in the coastal zone are underlined, and a new process-oriented approach is introduced for environmental licensing procedures. In Chapter III, an inventory and characterization of human interventions on the continental coast of the Colombian Caribbean are documented, to establish a regional baseline. Based on images from Google Earth, a total of 2,742 works and activities were located, representing 29 different types of human interventions. This inventory was complemented with an evaluation of the general impact of each intervention, based on four attributes of its geomorphological effects, namely, extension, intensity, reversibility, and persistence. The three most common types of human interventions (low-density settlements, groins and luxury settlements with dock) were also the ones with the higher environmental impact. However, some interventions (e.g., high-density settlements or road infrastructure) had higher environmental impact values than more frequent ones. 17 Based on this exhaustive analysis of the Colombian Caribbean, Chapter IV evaluates the national environmental regulatory framework applicable to coastal areas. It evidences that the licensing procedure in Colombia currently regulates only four of the ten types of interventions with greater effect in the Colombian coastal zones. Also, the number of works and activities covered in each new legislative reform consistently decreased over time. In addition, three policy implications were extracted for coastal and ocean planning, related to a) the geographic diversity of tropical coastal zones; b) the need for territorial carrying capacity instruments and; c) the lack of articulation of territorial planning instruments. The conclusions identify an important gap between technical and political decision making in the environmental regulatory framework of Colombia, which stresses the need for the design of novel methods to assess the breadth and length of geomorphological dynamics in an environmental management context. Therefore, the previous chapters highlight three important deficiencies in Colombia, with respect to the environmental management of human interventions in coastal areas: 1) the absence of a strategy to determine interventions that require an environmental licensing procedure (screening); 2) a poor definition of the scope of environmental studies through relevant information requirements (scoping) and; 3) the disarticulation of environmental management instruments, such as territorial planning and environmental licenses. All these elements ratify that the environmental regulatory framework in Colombia has been insufficient to date to manage the anthropogenic impact in coastal environments due to the unawareness of the natural susceptibility to the effect of human interventions. In this work, the susceptibility is defined as the predisposition of an environmental unit (socio-natural system) to experience changes or affectation due to the introduction of human interventions. In order to propose improvements to the Colombian environmental system, Chapter V establishes a new conceptual and methodological approach to guide the evaluation, monitoring, and control of human impacts from a geomorphological perspective. This novel product has been called Susceptibility to Human Interventions for Environmental Licensing Purposes (SHIELP). The architecture of this model has three components, which are particular to a kind of environment, namely, geomorphological processes, geomorphological configurations and potentially impacting human interventions. Each of these components is translated into a variable by means of expert qualifications along with a fuzzy logic computation strategy. Therefore, the expert-diffuse system SHIELP qualifies the susceptibility of a distinctive landform to the effects of a characteristic type of human intervention, through the estimated perturbation in each geomorphological process that configures the kind of environment under study. As a demonstration, this chapter also documents the design of the expert-diffuse system for coastal environments, drafted from research workshops with members of the marine and coastal research institute INVEMAR (In Spanish: Instituto de Investigaciones Marinas y Costeras “José Benito Vives de Andréis”). The role of this institute as an official adviser to the environmental authorities in matters of impact assessment demonstrates its relevance to support the expert-knowledge base of the model. 18 As a consequence, the SHIELP model was applied with the parameters established for coastal environments, resulting in a database of susceptibility values for 4,524 interactions (littoral configuration vs intervention). The real applicability of this exercise corresponds to the translation of this database into a technical criterion to improve the Colombian regulatory framework. On the one hand, five susceptibility ranges were linked to five differentiated instruments, two of which articulate environmental licensing with territorial plans, while the others differentiate the pertinent degree of licensing for human interventions according to location properties (screening). On the other hand, the differentiated instruments were also combined with four degrees of information requirements for the definition of the scope in the respective environmental studies (scoping). In this way, the susceptibility value of a given intervention in a given configuration (interaction) would fit a percentile range that places its environmental control in a territorial competence (regional or national), and through a specific licensing instrument, with differentiated information requirements for the baseline definition. Finally, the operation of the SHIELP model was also demonstrated with a case study: the environmental coastal unit Magdalena River - Canal del Dique complex - Ciénaga Grande de Santa Marta lagoon system. The geographic information of this regional coastal unit was interpreted according to the parameters defined in the SHIELP model for coastal environments. 154 polygons were delimited in the study area, according to the 40 coastal configurations identified. As a result, 13 cartographic maps represent this area, with the levels of susceptibility attributed to each configuration for the 52 potentially impacting interventions. In order to illustrate the applicability of the model, four scenarios are presented to discriminate interventions by environmental management instrument (screening) and to define information requirements on geomorphological processes (scoping). In this way, the SHIELP model specifies the environmental licensing instrument for human interventions and the corresponding scope of the technical study, given the characteristics of its interaction with the geomorphological configuration. The Overall Conclusions document reflections and recommendations to the Colombian national environmental system – SINA (in Spanish: Sistema Nacional Ambiental) to implement the results of this research. In addition, this work opens a broad perspective for future research in the approach of susceptibility to the effect of human interventions. The SHIELP model for coastal environments can be replicated in different geographies to progressively articulate a national database of coastal susceptibility. Also, the presented methodological scheme can be applied in different kinds of environments, other than the coastal zone. The extension of this approach of geomorphological susceptibility to the variety of tropical ecosystems would set the path for a successful transition from the current anthropocentric and fragmentation-oriented conception towards an ecosystem-based management approach.Ítem Bacillus sp. strains and their inducible in vitro antagonism : a biochemical and molecular study(Universidad EAFIT, 2018) Sierra Zapata, Laura; Villegas Escobar, Valeska; Romero Tabarez, MagallyDiscovering novel antibiotic substances from natural sources and revitalizing the pipeline for screenings of naturally sourced substances that could render new bioactive compounds, is a priority nowadays in the face of a world crisis of antimicrobial resistance. This research was focused on disclosing an observed antagonism system composed of Bacillus sp. strains producing inducible antimicrobial activity against the plant pathogen Ralstonia solanacearum, a widespread bacterium that causes bacterial wilt disease to a great variety of plant species, including many agriculturally important ones as are bananas. The inducible phenomenon was discovered during the screening of 1493 aerobic endospore forming bacteria against plant pathogens. It was observed that in the presence of the chemical compound Triphenyl Tetrazolium Chloride (TTC), which belongs to the group of synthetic compounds known as tetrazolium salts used to monitor cell respiration, Bacillus sp. strains produced inhibition zones against the bacterial plant pathogen and other pathogenic bacterial species, while in the absence of the compound they did not have any bioactivity. During biochemical characterization, it was evidenced that although the phenomenon was observable across several species of the order Bacillales, strains belonging to B. cereus, B. pumilus and B. subtilis were outstanding in their inducible antagonism potential, among other species tested. Besides, relevant traits revealed that other tetrazolium salts did not induce antagonistic activity and that the addition of antioxidant compounds did not reduce the inducible antagonistic activity. Also, R. solanacearum sensitivity to antibiotics was not increased by the addition of TTC and the inducible activity was independent of the presence of the pathogenic strain. In order to determine genes and pathways that were activated under TTC conditions, transcriptomic and metabolomics analysis were performed. Transcriptomic results revealed that specific pathways of the nitrogen metabolism, such as pyrimidines, purines and histidine biosynthetic routes, were 2 to 5 fold up-regulated in B. subtilis NCIB-3610 cells growing under TTC presence. On the other hand, metabolomic analysis showed that 28 specific compounds were either unique or 3 to 5 fold more abundant in active extracts obtained from inducible conditions, compared to non-induced controls. Data mining on public chemical databases, using intrinsic properties of the selected compounds, suggests that they mostly belong to chemical families of carbamates, imidazoles, pyrrolidines, pyrimidines, dipeptides and oligopeptides, all of which are part of the nitrogen metabolism. Results suggest that Bacillus cells reduction of TTC into triphenyl formazan (TPF) and its further accumulation inside the cells, induces the production of nitrogen-derived compounds, either by activation of nitrogen metabolism biosynthetic pathways or by a biotransformation of TPF into derivatives. Once produced, the compounds are secreted into the medium and act as antimicrobials against other bacteria.Ítem Caracterización del flujo hidrodinámico y evaluación de su impacto en la acumulación y producción de hidrocarburos en el sector sur de la Cuenca de Llanos, Colombia(Universidad EAFIT, 2022) Gómez Moncada, Ricardo Andrés; Jaramillo Uribe, Marcela; Mora Bohorquez, AndrésThe southern sector of the Llanos Basin in Colombia has been identified as a basin where the hydrodynamic flow has influenced the potential of hydrocarbon storage and production. In this area the hydrodynamic flow coincides with a province of heavy and extra-heavy crude oils, which has hypothesized for this area, a critical condition that decreases the potential for hydrocarbon retention by the effect of hydrodynamic flow and the geochemical nature of the fluids. This work provides a comprehensive view to describe the impact of regional hydrodynamic flow on retention of the heavy oil accumulations present in the reservoirs that are part of the most important regional flow unit identified in the Southern Llanos Basin. The Basal Flow Unit (BFU) constitutes a basin-scale flow unit that hydraulically and laterally connects rocks from the Cretaceous (west) to the Oligocene (east) and extends from the basin's southwestern margin up to hundreds of kilometers within the Llanos foreland basin, and whose main water recharge zone has been identified towards the eastern flank of the Serranía de la Macarena. To understand the impact of the physicochemical properties of the fluids, we analyze the relationship between hydraulic data and the main characteristics of the fluids present in the BFU, and their spatial distribution on the present-day configuration of this flow unit. This analysis integrated information from hydraulic heads, SARA analysis (Saturates, Aromatics, Resins, and Asphaltenes), Whole Oil Gas Chromatography analysis, API-gravity, and oil densities. In addition, hydrochemical analysis of the primary ions and isotopic analysis (δ18O and δD) was performed in groundwater samples from the BFU, which was integrated with deep resistivity data measured in producing and exploratory oil wells in the area. The new isotopic analyzes of this study (δ18O and δD), and data from previous studies, allowed establishing the Local Meteoric Water Line (LMWL) for the Llanos basin. The δ18O and δD values of the groundwater samples follow the Local Meteoric Water Line proposed for the Llanos basin, supporting the presence of meteoric waters in the Basal Flow Unit and whose influence it extends from the recharge zone to more than 300 km east of the basin. The results allowed identifying the southwestern corner of the southern Llanos Basin as the area with the highest hydrodynamic flow impact, and therefore, the area with the least potential for hydrocarbon retention, attributing as the main causes: 1) the proximity to recharge areas, and 2) the low contrast of fluids densities (freshwaters and highly biodegraded heavy crude oils), implying high Tilt Amplification Factor (TAF) values. Furthermore, gradual changes in resistivities and ions concentration in groundwaters suggest the eastern flank of the Serranía de la Macarena as the main recharge zone of meteoric waters into the BFU. Finally, numerical simulation techniques were used to analyze the behavior of hydrocarbon drainage under hydrodynamic conditions, obtaining a first approximation to the average linear groundwater flow velocities between 10-3 and 10-4 ft/day.Ítem Compendium of publications on: differential operators on manifolds for CAD CAM CAE and computer graphics(Universidad EAFIT, 2020) Mejía Parra, Daniel; Ruiz Salguero, Oscar Eduardo; Posada Velásquez, Jorge LeónThis Doctoral Thesis develops novel articulations of Differential Operators on Manifolds for applications on Computer Aided Design, Manufacture and Computer Graphics, as follows: (1) Mesh Parameterization and Segmentation. Development and application of Laplace-Beltrami, Hessian, Geodesic and Curvature operators for topology and geometry – driven segmentations and parameterizations of 2-manifold triangular meshes. Applications in Reverse Engineering, Manufacturing and Medicine. (2) Computing of Laser-driven Temperature Maps in thin plates. Spectral domain - based analytic solutions of the transient, non-homogeneous heat equation for simulation of temperature maps in multi-laser heated thin plates, modeled as 2-manifolds plus thickness. (3) Real-time estimation of dimensional compliance of hot out-of-forge workpieces. A Special Orthogonal SO(3) transformation between 2-manifolds is found, which enables a distance operator between 2-manifolds in R^3 (or m-manifolds in R^n). This process instruments the real-time assessment of dimensional compliance of hot workpieces, in the factory floor shop. (4) Slicing or Level-Set computation for 2-manifold triangular meshes in Additive Manufacturing. Development of a classification of non-degenerate (i.e. non-singular Hessian) and degenerate (i.e. singular Hessian) critical points of non-Morse functions on 2-manifold objects, followed by computation of level sets for Additive Manufacturing. Most of the aforementioned contributions have been screened and accepted by the international scientific community (and published). Non-published material corresponds to confidential developments which are commercially exploited by the sponsors and therefore banned from dissemination.Ítem Compendium on "assessment of intended deformations and kinematic identification of parallel mechanisms under quasi-static condictions"(Universidad EAFIT, 2010) Durango Idárraga, Sebastián; Ruíz Salguero, Óscar EduardoÍtem Computational Geometry Contributions Applied to Additive Manufacturing(Universidad EAFIT, 2022) Montoya Zapata, Diego Alejandro; Ruiz Salguero, Oscar Eduardo; Posada Velásquez, Jorge LeónÍtem Computational Geometry in Medical Applications(Universidad EAFIT, 2016) Cortés Acosta, Camilo Andrés; Ruíz Salguero, Óscar Eduardo; Flórez Esnal, JuliánÍtem Computational Study of Cell Mobility and Transport Phenomena Through Textile Vascular Grafts Using a Multi-Scale Approach(Universidad EAFIT, 2015) Valencia Cardona, Raúl Adolfo; García Ruíz, Manuel Julio; Bustamante Osorno, JohnTextile vascular grafts are biomedical devices that serve as partial replacement of damaged arterial vessels, prevent aneurysms rupture and restore normal blood flow -- It is believed that the success of a textile vascular graft, in the healing process after implantation, is due to the porous micro-structure of the wall -- Among the key properties that take part in the tissue repair process are the type of fabric and degree of porosity and permeability, defining the ability of a well-controlled environment for the neovascularization, nutrient supply, and cellular transport -- Although the transport of fluids through textiles is of great technical interest in biomedical applications, little is known about predicting the micro-flow pattern and the transport and deposition of individual platelets, related with the graft occlusion -- Often, this information is difficult to obtain experimentally both in vivo and in vitro, representing a great deal of research efforts -- The aim of this work is to investigate how the type of fabric, permeability and porosity affect both the local fluid dynamics at several scales and the fluid-particle interaction among platelets in textile grafts with an anastomosis of end-to-end configuration -- Two types of samples were analyzed: woven and electrospun, this last one has been manufactured -- This study involves both experimental and computational tests -- The experimental tests were performed to characterize the permeability and porosity under static conditions -- The computational tests are based on a multiscale approach where the fluid flow was solved with the Finite Element Method and the discrete particles were solved with the Molecular Dynamic Method -- The fluid-particle interaction was accomplished in one-, two-, and four-ways, where the blood was considered as a suspension of platelets in plasma -- The textile wall was considered as a porous media with two scales of length: straight tubular structure with porous walls for the macro-domain and representative unit cells of fabric for the micro-domain. Additionally, it presents the implementation of a numerical case that includes one of the main applications of textile vascular grafts to repair Abdominal Aortic Aneurysms (AAA) -- The results have shown that the type of fabric in textile vascular grafts and the degree of porosity and permeability affect the local fluid dynamics and the level of penetration of platelet particles through the graft wall at several length scales, thus indicating their importance as design parameters -- It was found that the permeability is strongly depends on the micro-structure of the fabric, changing the local fluid dynamics and the time of residence of platelets inside the wall -- Moreover, the porous walls cause deviations from Poiseuille flow due to leakage flow through the wall from a macroscopic viewpoint -- Lastly, it was possible to observe that the textile wall with different porosities, acting like a barrier between the blood and an aneurysmal zone, affects the flow pattern, the number of platelets adhered to the artificial surface and the time of residence of platelets into the aneurysmal zone -- In conclusion, predicting the flow pattern and the mobility of blood cells through the textile wall before the graft is manufactured, the development of new textile grafts can be improvedÍtem Data assimilation in a lotos-euros chemical transport model for Colombia using satellite measurements(Universidad EAFIT, 2023) Yarce Botero, Andrés; Quintero Montoya, Olga Lucía; Heemink, ArnoldWhen considering air quality, notably in South America, it seems that we are falling behind more developed regions in exacerbating the issue. This shortfall serves not just as observation, but as a warning, as air quality problems here are rapidly escalating. Nevertheless, by examining how other countries have addressed similar issues, we can prepare ourselves to tackle our own challenges. In this thesis we demonstrate how utilizing Data Assimilation DA we can reduce the uncertainty in some model uncertain parameters in an air quality model such as the LOTOS-EUROS Chemical Transport Model (CTM). CTMs are critical for representing reality through numerical simulations of concentrations of atmospheric constituents. These models incorporate various processes, including emissions, transportation, chemical reactions, and deposition. It is imperative to use accurate models as they enable us to understand atmospheric processes better and develop effective solutions to environmental problems, more in regions with scarce measurenments. The LOTOS-EUROS model is employed, whereby the portrayal of reality accounts for uncertainty from multiple sources. To enhance model output, it is crucial to maximise the representativeness of the input information. From a measurement perspective in Colombia, there is an evident scarcity of ground-level equipment to monitor air quality in a comprehensive manner. The principal urban areas are monitored but extensive regions remain unobserved. This is precisely where satellite data, together with cost-effective sensors, prove advantageous by offering a more comprehensive range. Satellite air quality data has become increasingly available and its temporal and spatial resolution improves. However, cloud coverage, particularly around the Andean mountains, often obstructs satellite observations. This dissertation uses TROPOMI satellite-derived NO$_2$ concentrations as the primary data source for assessing air quality in tropical regions. Furthermore, this thesis involved the development of a customised electronic hardware device specifically designed to collect in-situ measurements in a mountainous region, to compare models and perform remote data assimilation experiments. Data assimilation (DA) methods can be divided into two main categories: sequential and variational methods. Sequential methods introduce observations progressively as they become available. On the contrary, variational methods adopt a wider perspective by assimilating observations over a predetermined time frame and refining model accuracy through optimizing a cost function. The 4D Var method is a noteworthy variational method that finds application in atmospheric sciences. The method employs an adjoint model that is a crucial component in enabling the optimization process through the computation of gradients that are vital for minimizing the cost function. The implementation of adjoint models, however, poses significant challenges, involving complex coding and maintenance requirements. These challenges are more pronounced when working in the area of Chemical Transport Model (CTM), where the goal is to significantly improve the physical modelling system based on an adjoint model that is not always available. To overcome the hurdles related to adjoint models, this study explored adjoint-free data assimilation techniques. Adjoint-free methods, such as the 4DEnVar and the Local Ensemble Kalman Filter (LEnKF), employ ensemble propagation within the model to estimate variables, presenting a practical substitute. The research explored parameters that modulate emission model uncertainties as a means to reduce CTM-related uncertainties, given the focus on emissions as a significant contributing factor. Conducting experiments in various urban and rural locations in Colombia enabled a more nuanced comprehension of emission parameters. The innovative use of ensemble-based data assimilation techniques, including the 4DEnVar and LEnKF, along with the incorporation of satellite observations, has substantially enhanced the refinement of emission parameters. The combination of chemical transport models (CTMs), satellite data, low-cost sensors, and data assimilation (DA) has led to significant progress in measuring atmospheric pollutants and forecasting emissions in Colombia. The integration of the LOTOS-EUROS model, improvements in satellite data processing, and alignment of sensors has substantially enhanced the region's atmospheric chemistry modelling capabilities in the region. Moreover, the implemented data assimilation techniques have proven effective in improving the precision of air quality models, strengthening the correlation between model projections and real-world observations.Ítem Desarrollo de un electrodo bioinspirado para generación de Hidrógeno(Universidad EAFIT, 2024) Carmona Saldarriaga, Laura; Ossa Henao, Edgar AlexanderÍtem Desarrollo de un proceso continuo para medicamentos antiinflamatorios con ingredientes activos de baja solubilidad que garanticen mayor eficacia y mejor solubilidad en excipientes poliméricos(Universidad EAFIT, 2019) Restrepo Uribe, Laura; Noriega Escobar, María del PilarÍtem Design and analysis of photovoltaic surfaces based on a multiphysics approach(Universidad EAFIT, 2023) Espitia Mesa, Gabriel Jaime; Mejía Gutiérrez, RicardoÍtem Efectos de la interacción de los hidrocarburos sobre la diagénesis en reservorios de areniscas siliciclásticas. Ejemplo formación mugrosa, cuenca valle medio del Magdalena (VMM), Colombia(Universidad EAFIT, 2023) Palmera Henao, Tania Sarith; Marín Cerón, María Isabel; García González, MarioÍtem Energy management strategy for a solar race car including meteorologic and probabilistic variable(2018) Betancur Valencia, Esteban; Osorio Gómez, GilbertoThis thesis describes the energy management strategy for racing solar cars, the racing strategy is treated as an optimal control problem with random variables and uncertain predictions. A computational model is developed for estimating the vehicle performance under specific circumstances. Two evolutionary heuristic optimization methods are implemented and tested for this case, their effectiveness, convergence and efficiency is measured and compared to exhaustive search approaches. The dependency on solar radiation is validated using the computational model with different test cases. In order to reduce the uncertainties on the solar radiation estimation, satellite images are used as inputs to image processing and machine learning techniques, their efficacy is compared. Finally, a validation case is executed and different scenarios are evaluated with the inclusion of the proposed methods, the experimental performance of a vehicle obtained using the strategy in the World Solar Challenge 2015 is exposed and compared to the predicted results from the simulation.Ítem Engineering estimation of topographic effects in site response analysis(Universidad EAFIT, 2021) Vergara Gallego, Juan Carlos; Gómez Cataño, Juan DavidDespite the irrefutable amount of theoretical and field evidence of the impact of topographic effects on the local response at a site the engineering community still lacks practical methods for its consideration in a standard routinely basis. The incorporation of topographic effects into site response analysis has been a major challenge to engineers as it involves coupling between mechanical and geometric modifications to the incident seismic waves, which at the same time demands for field data that is rarely available to the practicing engineer. On the other hand, it has been observed that the main signature of topographic effects, besides the expected change in frequency con tent, is its spatial variation. These complexities combined to the field data required to build fully coupled mechanical-geometrical models have resulted in complete under consideration of these effects. In this work we follow a rational approach to study the effect of surface topography on the response at local sites after formulating the problem following a diffraction perspective. Since this work is framed in an engineering context our main result is a method to incorporate the effect of surface topography in ground response analysis. Although the method requires numerical simulations we show that if the analyst brings into the problem the dynamic properties of the structure for which the analysis is conducted in the first place very moderate models may be required. These idea leads to the concept of size conditioned response spectra which uses a target structural response spectra to fix the size of the computational model. The resulting numerical domain turns out to be of manageable size thus it can be handled with standard computing resources. Although our proposed approach is limited to surface topography the combination of the theory of diffracted waves and the consideration of the structural response creates new venues to advance in understanding the problem of topographic effects.Ítem Ensemble-based Data Assimilation For High-uncertainty systems: a case of study with Particulate Matter in the Aburrá Valley(TU Delft, 2021) López Restrepo, Santiago; Quintero Montoya, Olga Lucía
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