Abstract: Several studies have shown that site measurements of the buffeting responses of long-span bridges do not always agree with predictions from analytical models. The observed discrepancy is believed to be explained by the variability in the wind’s turbulence field, which is ignored in the current design guidelines. Additionally, the guidelines neglect the true variability in the buffeting response, as this parameter is considered to be deterministically dependent on the mean wind speed only, and a single short-term-averaged wind condition is assumed to be representative of the bridge’s behaviour over its lifetime. Such assumptions underestimate the design buffeting response. Alternatively, a full long-term analysis is regarded as the most accurate approach to handling extreme response estimations. Applications of this analysis in the wind engineering literature are scarce due to its large computational demand. With the objective of alleviating such demand, this paper proposes a full long-term analysis framework based on importance sampling Monte Carlo (ISMC) simulations and investigates, for the first time, the extreme buffeting response of a suspension bridge in its design phase with this framework. The results were compared with available formulations based on reliability methods and numerical integration. The proposed ISMC framework requires fewer simulations than the other formulations while maintaining a good degree of accuracy. The results show that the estimated extreme response is 30% larger than the current design guidelines suggest, showing the importance of considering the turbulence parameters' and loading effects' variabilities when calculating extreme responses. Resumen: Diferentes estudios han mostrado que las mediciones en sitio de respuesta estructural de puentes colgantes ante acción del viento no coinciden con los modelos matemáticos que usamos hoy en día. La discrepancia puede ser explicada si se considera en el análisis la variabilidad de la turbulencia del viento. Sin embargo, esta no se incluye en las normas de diseño actuales. Adicionalmente, las normas ignoran la variabilidad misma de la respuesta. Este parámetro se considera determinístico tomando una sola condición de viento como representativa sobre toda la vida útil del puente. Estas suposiciones dan estimaciones erradas de la respuesta estructural de puentes colgantes. Alternativamente, el análisis de valores extremos a largo termino es considerado la metodología más precisa para este tipo de estimaciones ya que incluye la variabilidad de la turbulencia y la respuesta. Aplicaciones de este tipo de análisis son escasas debido a su exhaustiva demanda computacional. Con el objetivo de aliviar dicha demanda, este artículo presenta una formulación del análisis de largo tiempo usando simulaciones de Monte Carlo con muestreo por importancia. Este artículo investiga por primera vez la respuesta de un puente colgante en fase de diseño con este tipo de análisis. Los resultados fueron comparados con las otras formulaciones basados en métodos de confiabilidad e integración numérica. La formulación propuesta requiere menos simulaciones que las otras formulaciones sin demeritar la precisión en las estimaciones. Los resultados muestran que la respuesta extrema estimada con métodos de largo termino es 30% mayor que la respuesta estimada con los métodos actuales. De esta manera se comprueba que la variabilidad de la turbulencia y de la respuesta misma deben ser tenidos en cuenta en el diseño de puentes colgantes. * Nota: Los resultados de esta investigación (y estudios similares), sirvieron de base teórica para que el análisis de valores extremos a largo termino fuese incluido en la nueva edición norma de diseño de puentes en Noruega N400 (https://viewers.vegnorm.vegvesen.no/product/859933/nb) Esperamos que en el futuro regulaciones de otros países adopten el método.

Abstract: The conventional top-down scope of relying only on centralised sewerage has proven insufficient to reach the entire global population with safely managed sanitation and meet Sustainable Development Goals 6.2. and 6.3 by 2030. Citywide Inclusive Sanitation (CWIS) has emerged as an approach to accelerate progress by considering different technologies and service provision models within the same city to expand sanitation access equitably and sustainably. However, to generate an enabling environment for CWIS to be implemented successfully, regulatory frameworks must be adapted, as they are often unsuited for non-sewered sanitation solutions. By analysing the Colombian case study through a mixed qualitative methodology comprised of a policy review, semi-structured interviews, and workshops with key stakeholders in the urban sanitation sector, the country’s regulatory framework was evaluated to determine if it is adequate to implement CWIS. Regulations were identified to pose barriers for CWIS and produced a disabling environment for its application. This research proposes recommendations to adapt the regulatory framework to allow CWIS application in Colombia based on the encountered barriers. This is the first comprehensive study on regulations for CWIS in the Latin American context and therefore provides the basis for further research to understand the dynamics related to effective regulations for CWIS globally.

Abstract: Microfluidics is a relatively recent technology which involves the manipulation of fluids geometrically constrained to small scales. These devices have been gaining attention, especially due to the broad range of potential applications, being one of them microreactors. In this project, the optimum flow conditions for generation droplets under merging regime were established, identifying most important variables, which influence the regime desired in this type of application. Capillary and Reynolds numbers were found as the parameters which determine the region in which the system is performed. These numbers are subject to the interfacial tension, viscosity, and flowrate which are the most sensitive variables that modify all the regimes. Likewise, it was identified that the geometry of the microdevice influences on the system. Therefore, several microdevices were designed with different geometries where the viscosity, the flowrate, and the width ratio were varied at fixed interfacial tension, to assess their impact. It was found that by increasing the viscosity and flowrate, the shear forces inside the microdevices increase proportionally, giving way to undesired laminar regimes and bigger droplets. The width ratio has an indirect impact on the regime obtained, by increasing the amount of water entering the main channel. Phase diagrams illustrate the optimal conditions for merging regime, where the most optimal values found to have this regime and smallest droplet were by using width ratio of 1, and flowrates of 3.5ml/h and 0.8ml/h in the continuous phase and dispersed phases, respectively, using silicone oil of 5cSt. The results found in this study can contribute to the development of further research, including the formation of nanoparticles to carry out chemical reactions in a micro scale. Resumen: La microfluídica es una tecnología relativamente reciente que implica la manipulación de fluidos restringidos geométricamente a pequeñas escalas. Estos dispositivos han ido ganando atención, especialmente debido a la amplia gama de aplicaciones potenciales, siendo una de ellas los microrreactores. En este proyecto se establecieron las condiciones óptimas de flujo para la generación de gotas en régimen de fusión, identificando las variables más importantes, que influyen en el régimen deseado en este tipo de aplicación. Los números de capilaridad y de Reynolds se encontraron como los parámetros que determinan la región en la que se desarrolla el sistema. Estos números están sujetos a la tensión interfacial, la viscosidad y el caudal, que son las variables más sensibles que modifican todos los regímenes. Asimismo, se identificó que la geometría del microdispositivo influye en el sistema. Por lo tanto, se diseñaron varios microdispositivos con diferentes geometrías en los que la viscosidad, la velocidad de flujo y la relación de anchura se variaron a una tensión interfacial fija, para evaluar su impacto. Se comprobó que al aumentar la viscosidad y la velocidad de flujo, las fuerzas de cizallamiento en el interior de los microdispositivos aumentan proporcionalmente, dando lugar a regímenes laminares no deseados y a gotas más grandes. La relación de anchura tiene un impacto indirecto en el régimen obtenido, al aumentar la cantidad de agua que entra en el canal principal. Los diagramas de fase ilustran las condiciones óptimas para el régimen de fusión, donde los valores más óptimos encontrados para tener este régimen y la gota más pequeña fueron utilizandos a una la relación de anchura de 1, y caudales de 3,5ml/h y 0,8ml/h en la fase continua y en la fase dispersa, respectivamente, utilizando aceite de silicona de 5cSt. Los resultados encontrados en este estudio pueden contribuir al desarrollo de nuevas investigaciones, incluyendo la formación de nanopartículas para llevar a cabo reacciones químicas a microescala.

Abstract: The 2016 peace accords between the Colombian state and the FARC created great expectations of peace across the region. However, four years later, Colombia is experiencing a growing wave of violence from numerous actors, including former FARC dissidents. What drove the emergence of splinter groups after the 2016 peace accords? This thesis argues that insurgents’ levels of cohesiveness and ideological commitment during negotiations significantly condition the long-term prospects for successful accord implementation. When insurgencies enter these processes with low levels of these two factors, peace accords tend to transform, rather than end, the conflict. The thesis examines this argument through an analysis of the FARC’s organizational and ideological properties throughout history and finds that while the FARC had traditionally been a cohesive organization, during the 2000s the COIN strategy and Plan Colombia weakened its organizational structure. Furthermore, its incorporation in the drug trade contributed to the dilution of its ideological commitment. When accords were signed, the FARC lacked the necessary levels of cohesiveness and commitment to implement and enforce the accords in their ranks, causing the emergence of splinter groups. This thesis recommends that in an eventual negotiation with insurgencies, governments must give careful consideration to both the organizational and ideological properties of such organizations to avoid splintering and recurrence of violence.

Abstract: Information regarding the state of bridges is fundamental for maintaining a satisfactory performance level, given that deterioration may lead to bridge failure and thus, increased costs. Bridges face harsh environmental conditions and natural disasters are often inevitable and can be one of the main reasons for bridge collapse. Consequences from flooding events (e.g., scour) are responsible for a large percentage of failures in bridge structures. Therefore, the assessment of bridges susceptible to these phenomena is of utmost importance to identify possible mitigation needs. The objective of the present research is to present a consistent framework to obtain fragility curves associated with the inplane behavior of masonry arch bridges (MAB) under flood hazard. By implementing metamodeling techniques to the probabilistic analysis, a computational cost-efficient framework is proposed which is employed on a MAB “Ponte da Vala do Carregado” located in Portugal. A two-dimensional numerical model was constructed where the random variables that affect the structural capacity and the scouring process were considered. Finally, a parametric analysis, based on the geometric variations of the bridge structure and geotechnical variations of the foundation material (bed material), was implemented. The fragility curves show that failure probability increases when flow discharge increases, especially when the skew flow was considered. This will allow assessing the performance of bridges that may affect the network efficiency at important sections of the roadway system if damaged by a flood event. Resumen: La información sobre el estado de los puentes es fundamental para mantener un nivel de desempeño satisfactorio, dado que el deterioro puede conducir a la falla del puente y, por ende, a un aumento de los costos. Los puentes enfrentan duras condiciones ambientales y los desastres naturales a menudo son inevitables y pueden ser una de las principales razones del colapso del puente. Las consecuencias de las inundaciones (por ejemplo, la socavación) son responsables de un gran porcentaje de fallas en las estructuras de los puentes. Por lo tanto, la evaluación de puentes susceptibles a estos fenómenos es de suma importancia para identificar posibles necesidades de mitigación. El objetivo de la presente investigación es presentar un marco consistente para obtener curvas de fragilidad asociadas con el comportamiento en el plano de puentes de arco de mampostería (MAB) bajo peligro de inundación. Mediante la implementación de técnicas de metamodelado para el análisis probabilístico, se propone un marco computacional rentable que se emplea en un MAB ""Ponte da Vala do Carregado"" ubicado en Portugal. Se construyó un modelo numérico bidimensional donde se consideraron las variables aleatorias que afectan la capacidad estructural y el proceso de socavación. Finalmente, se implementó un análisis paramétrico, basado en las variaciones geométricas de la estructura del puente y las variaciones geotécnicas del material de cimentación (material del lecho). Las curvas de fragilidad muestran que la probabilidad de falla aumenta cuando aumenta la descarga del flujo, especialmente cuando se considera el flujo sesgado. Esto permitirá evaluar el desempeño de los puentes que pueden afectar la eficiencia de la red en secciones importantes del sistema vial si se dañan por una inundación.

Abstract: This essay seeks to establish the way in which the American TV show Bizarre Foods Americas builds up identities and meanings about the Getsemaní neighborhood (Cartagena de Indias, Colombia), during the interaction between an English-speaking 'adventurous cook' and the local people of the neighborhood, through multimodal resources. To describe and interpret the data we resort, on one hand, to virtual ethnography (Domínguez, et.al., 2007; Pauwels, 2012) and, on the other, to concepts related to language and globalization to explain the construction of identities (Blommaert, 2010; Pietikäinen, 2018; Menezes de Souza, 2019; Stroud, 2017). The results show that through a diverse repertoire of semiotic resources used during the program, different local identity traits are established. Results also evidence the perpetuation and legitimization of adverse social phenomena for the local population referred to unequal social relations of power and colonialist discourses. Resumen: Este ensayo busca establecer el modo como el programa de TV estadounidense Bizarre Foods Americas construye identidades y significaciones acerca del barrio Getsemaní (Cartagena de Indias, Colombia) en la interacción entre un 'cocinero aventurero' de habla inglesa y la gente local del barrio, mediante recursos multimodales. Para la descripción e interpretación de los datos acudimos, por un lado, a la etnografía virtual (Domínguez, et.al., 2007; Pauwels, 2012) y, por otro, a conceptos relacionados con el lenguaje y la globalización para explicar la construcción de identidades (Blommaert, 2010; Pietikäinen, 2018; Menezes de Souza, 2019; Stroud, 2017). Los resultados muestran que, a través de un diverso repertorio de recursos semióticos utilizados durante el programa, se establecen distintos elementos identitarios locales así como la perpetuación y legitimización de fenómenos sociales adversos para la población local referidos a relaciones sociales desiguales de poder y discursos colonialistas.

Abstract: This study conducts an overview of false cognates between Spanish and Portuguese to propose the didactic strategy of associative mnemonics: associative images with associative sentences, this with the aim of reducing interference and improving the accuracy at the time of recalling false cognates. The study was designed with 30 Spanish-native Colombian speakers who learn Portuguese as a foreign language at the University. The findings show that the associative mnemonics improve participants performance just when associative images are included (experimental group) rather than just associative sentences (control group), there was a rising of 25,8% when comparing groups with and without associative images. Participants also demonstrated different perceptions of the cognates depending on the type of task that they face. Linking individual translations between both languages showed a performance of 85%, but when the task was about a written description of pictures, the performance lowered to 54%. This study gives light to the need of teachers and students to find diverse metacognitive techniques to differentiate complex lexicon in both languages. Resumen: Este estudio realiza un recorrido por los falsos cognados entre español y portugués para proponer la estrategia didáctica de la mnemotécnica asociativa: imágenes asociativas con frases asociativas, esto con el objetivo de reducir la interferencia y mejorar la precisión al momento de recordar falsos cognados. El estudio fue diseñado con 30 hispanohablantes colombianos que aprenden portugués como lengua extranjera en la Universidad. Los hallazgos muestran que los mnemotécnicos asociativos mejoran el rendimiento de los participantes solo cuando se incluyen imágenes asociativas (grupo experimental) en lugar de solo frases asociativas (grupo control), hubo un incremento del 25,8% al comparar grupos con y sin imágenes asociativas. Los participantes también demostraron diferentes percepciones de los cognados según el tipo de tarea que desempeñan. Las traducciones individuales entre ambos idiomas mostraron un rendimiento del 85 %, pero cuando la tarea se trataba de una descripción escrita de imágenes, el rendimiento bajó al 54 %. Este estudio revela la necesidad de docentes y estudiantes de encontrar diversas técnicas metacognitivas para diferenciar léxicos complejos en ambas lenguas.

Abstract: Natural disasters are unavoidable and can cause serious damage to bridges, which maylead to catastrophic losses, both human and economic. Therefore, the assessment of bridges exposedto these events is of paramount importance to identify possible mitigation needs. The objective ofthe present work is to present consistent tools that may allow us to obtain the failure probability of amasonry arch bridge under a flood event, leading to local scour. Surrogate models were implementedto ease the computational cost of the probabilistic analysis. Moreover, a stochastic parametric analysisbased on the geotechnical properties of the soil components of masonry arch bridges located inPortugal was performed. The results show the failure mechanism of the masonry arch bridges whensubjected to scour-induced settlements and the influence of soil density on the failure probabilityobtained for different flow discharge values and angles of attack. The presented methodology andderived fragility curves can be used to assess bridge performance under a flood event, thus providinguseful information for bridge management and monitoring. Resumen: Los desastres naturales son inevitables y pueden causar graves daños a los puentes, lo que puede provocar pérdidas catastróficas, tanto humanas como económicas. Por lo tanto, la evaluación de los puentes expuestos a estos eventos es de suma importancia para identificar las posibles necesidades de mitigación. El objetivo del presente trabajo es presentar herramientas consistentes que nos permitan obtener la probabilidad de falla de un puente de arco de mampostería bajo un evento de inundación, conduciendo a una socavación local. Se implementaron metamodelos para reducir el costo computacional del análisis probabilístico. Además, se realizó un análisis paramétrico estocástico basado en las propiedades geotécnicas de los componentes del suelo de los puentes de arco de mampostería ubicados en Portugal. Los resultados muestran el mecanismo de falla de los puentes de arco de mampostería cuando se someten a asentamientos inducidos por socavación y la influencia de la densidad del suelo en la probabilidad de falla obtenida para diferentes valores de caudal y ángulos de ataque. La metodología presentada y las curvas de fragilidad derivadas se pueden usar para evaluar el desempeño del puente bajo un evento de inundación, proporcionando así información útil para la gestión y el monitoreo del puente.

Abstract: This project follows the complete development process of a sustainable building which intend to optimize the natural and built conditions, to merge the architecture with the sustainability; applied to the renovation of the BUILDING H in Palogrande Campus, Universidad Nacional de Colombia in the city of Manizales. Along this work the author put in practice the different methods of analysis and problem solution learned in the Politecnico di Milano, which are oriented to create a user experience focused in the current necessity of saving energy, having at simple sight the building spaces, systems, elements and components which will work to carry out this purpose, being the building use an interactive process between the users and the sustainability. A holistic approach leads the present project, starting from a general analysis of the physical, environmental, historical and social context at country, city, university and campus scale; the urban analysis considers the campus and its surrounding area, yet the design has been limited to the campus area; the architectural design follows the physical and social necessities and is connected with the sustainable strategies which intend to create an comfort environment with a low energy consumption; the details of the systems, elements and components are presented, as well as the structure analysis. Photographs, plans, schemes and renders illustrate the process and result. All the solutions proposed are ecofriendly oriented and expect to be a reference for future studies and design projects in another cities and functions.

Abstract: This work presents a study of mixed molybdenum vanadium and tungsten oxides applied to oxidative dehydrogenation of ethane (ODE). Different oxides were prepared by a microwave-assisted hydrothermal method using oxalic acid as a reducing agent to obtain a crystalline phase of composition (Mo0.52V0.38W0.1)2O5. The materials were studied by XRF, BET, X-ray poder diffraction (XRD), transmission electron microscopy, IR, UV–Vis, TPR-H2 and XPS spectroscopy. The structure with space group C2/m is closely related to that of R–Nb2O5 with cell parameters a ¼ 1215.1 p.m., b ¼ 374.2 p.m., c ¼ 402.0 p.m., and ? ¼ 90.70. This phase is stable under reaction and active and selective to ethylene in the ODE reaction. Comparison with the literature indicates that R–Nb2O5-type matrices constitute an alternative to Mo5O14-type oxides to control the selectivity of active species in ODE.