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Colección institucional

Tesis y artículos académicos

En esta colección encontrarás los productos de investigación académica de beneficiarios de COLFUTURO y Fulbright, en diversas disciplinas, como arte, biología, administración e ingeniería.

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    • 1225 Tesis
    • 5 Audios
    • 820 Artículos
  • Creada el:
    • 15 de Julio de 2019
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Creador Biblioteca Virtual Banco de la República
Imagen de apoyo de  Propriedades mecânicas de juntas de tubos de aço API X80 soldadas com arames tubulares

Propriedades mecânicas de juntas de tubos de aço API X80 soldadas com arames tubulares

Por: Robert Eduardo Cooper Ordóñez | Fecha: 2003

Resumo: Recentemente, o processo de soldagem a arco com arame tubular (FCAW) começou a ser aplicado na soldagem de dutos, no entanto, poucas informações científicas estão disponíveis sobre as propriedades das juntas e parâmetros de soldagem adequados para o real aproveitamento deste processo na soldagem em dutos. Neste trabalho é apresentado um estudo do efeito da temperatura de preaquecimento e do tipo de arame tubular sobre a microdureza e resistência à tração de juntas soldadas do aço API grau X80. Para tanto, foi usado o processo de soldagem a arco com eletrodo tubular com e sem proteção gasosa. As soldas foram efetuadas em tubos com diâmetro de 30” e espessura de 0,625”. As variáveis de influência deste trabalho experimental foram: o tipo de arame tubular e a temperatura de preaquecimento. As juntas soldadas foram avaliadas conforme as normas API 1104 para os ensaios de tração e ASTM E384-99 para os ensaios de microdureza. Os resultados mostraram que, as propriedades mecânicas (resistência à tração e microdureza) das juntas foram superiores às do metal de base e que as propriedades não foram afetadas pelo tipo de arame tubular e pelas temperaturas de preaquecimento. Abstract: Flux Core Arc Welding processes (FCAW) are beginning to be applied in pipeline welds, however, very limited experimental data regarding mechanical properties of pipeline weld joints with these processes are available in the literature. In this paper, the effects of preheat temperature and type of FCAW on mechanical properties (microhardness and tensile strength) of API X80 weld joint steel are presented. FCAW processes with gas protection and self-shielded were used. Multipasses welding were applied in 30” diameter and 0,625” thickness tubes. Influence factors were: FCAW type and preheat temperature. Acceptance criteria of welded joints were evaluated by API 1104 standard for tensile strength test and ASTM E384-99 for microhardness test. The results obtained showed that FCAW type and preheat temperature have no influence on mechanical properties of API X80 joint steel.
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Propriedades mecânicas de juntas de tubos de aço API X80 soldadas com arames tubulares

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Imagen de apoyo de  Mapeamento da cadeia de valor na transformação de chapas

Mapeamento da cadeia de valor na transformação de chapas

Por: Robert Eduardo; Damasceno Calado Cooper Ordóñez | Fecha: 2003

Os processos de manufatura das organizações industriais apresentam, na maioria dasvezes, oportunidades de melhorias. Seria normal priorizar onde se deve atuar, pois existem áreas de otimização, porém encontram-se também áreas com diversos problemas cujo objetivo maior é, em um primeiro momento, realizar ações de contingência para se dar um tempo adequado até que resoluções corretivas definitivas sejam tomadas. É nesse sentido que se apresenta neste trabalho os principais conceitos do “Mapeamento do Fluxo da Cadeia de Valor” e um caso simples de utilização em um processo de transformação de chapa, porque, há muito tempo, tem-se presenciado experiencias positivas na utilização das técnicas do pensamento enxuto e de qualidade total. Acreditamos que o mapeamento é uma prática eficaz de observar o valor agregado de maneira simples, podendo-se contribuir para a redução das perdas e transformação do sistema tradicional de produção para um sistema de produção de valor onde a qualidade passa a ser uma conseqüência do sistema enxuto.
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Mapeamento da cadeia de valor na transformação de chapas

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Imagen de apoyo de  Estudo de trincas inducidas pelo  hidrogenio no metal  de solida do aço API X80 através do teste G-BOP

Estudo de trincas inducidas pelo hidrogenio no metal de solida do aço API X80 através do teste G-BOP

Por: Robert Eduardo; Ferreira da Silva Cooper Ordóñez | Fecha: 2004

Um dos defeitos mais grave relativo à soldagem dos aços de Alta Resistência e Baixa Liga(ARBL) são as indesejáveis trincas induzidas pelo hidrogênio (TIH), também conhecidas comotrincas a frio. Dentre os vários testes de soldabilidade utilizados para avaliar a susceptibilidade dejuntas soldadas quanto ao trincamento induzido pelo hidrogênio, o teste G-BOP (Gapped Bead-on-Plate) apresenta-se com um grande potencial para avaliar trincas a frio no metal de solda. As principais vantagens deste teste são: simplicidade e segurança na quantificação dasusceptibilidade a trincas na zona do metal de solda - MS, e aplicação para estabelecer níveismínimos de temperaturas de preaquecimento. Recentemente, o processo de soldagem a arco com arame tubular (FCAW) começou a ser aplicado na soldagem de dutos; o uso de arames tubular, em particular os autoprotegidos, tem se mostrado bastante promissor para soldagem de dutos nocampo, uma vez que, o arame tubular autoprotegido apresenta-se como a melhor opção à substituição do eletrodo revestido. Este trabalho tem como objetivo a aplicação do teste G-BOP para avaliar trincas de hidrogênio no metal de solda do aço API X80 e estudar a sua viabilidade para avaliar a influência da temperatura de preaquecimento na susceptibilidade à trinca inducida pelo hidrogênio de metais de solda do aço API X80 executados com o arame tubular autoprotegido E71T8-K6. Um Planejamento Aleatorizado por Níveis (PAN), foi usado para o desenvolvimento dos ensaios experimentais e análise dos resultados, correlacionando a presença e percentual de trincas no cordão de solda com a temperatura de preaquecimento. Os resultados mostraram que o teste G-BOP foi eficiente para avaliar a influência da temperatura de preaquecimento na formação de trincas no metal de solda e que o reaquecimento minimiza a susceptibilidade a trincas a frio de soldas do aço API X80, com o arame tubular autoprotegido.
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Estudo de trincas inducidas pelo hidrogenio no metal de solida do aço API X80 através do teste G-BOP

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Imagen de apoyo de  Are the New Physics Contributions from the Left-Right Symmetric Model Important for the Indirect CP Violation in the Neutral B Mesons?

Are the New Physics Contributions from the Left-Right Symmetric Model Important for the Indirect CP Violation in the Neutral B Mesons?

Por: Yeinzon; Quimbay Rodríguez García | Fecha: 2005

Several works analyzing the new physics contributions from the LeftRight Symmetric Model to the CP violation phenomena in the neutral B mesons can be found in the literature. These works exhibit interesting and experimentally sensible deviations from the Standard Model predictions but at the expense of considering a low right scale ?R around 1 TeV. However, when we stick to the more conservative estimates for ?R which say that it must be at least 107 GeV, no experimentally sensible deviations from the Standard Model appear for indirect CP violation. This estimate for ?R arises when the generation of neutrino masses is considered. In spite of the fact that this scenario is much less interesting and says nothing new about both the CP violation phenomenon and the structure of the LeftRight Symmetric Model, this possibility must be taken into account for the sake of completeness and when considering the see-saw mechanism that provides masses to the neutrino sector.
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Are the New Physics Contributions from the Left-Right Symmetric Model Important for the Indirect CP Violation in the Neutral B Mesons?

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Imagen de apoyo de  Making Housing Policy Work The Millennium Housing Project

Making Housing Policy Work The Millennium Housing Project

Por: Gabriel Nagy Patiño | Fecha: 2004

Con un año de retraso y dos veces el presupuesto original, el parque del “Milenio” abrio sus puertas a los habitantes de la ciudad de Chicago durant el pasado verano (2004). Este es uno de tantos proyectos de rahabilitación urban que a nivel mundial se desarrollaron antes o después del cambio de siglo. Otros mega-proyectos, de alto impacto urbano y asociados a celebraciones especiales han sido las instalaciones y escenarios deportivos para celebrar las olimpiadas. Unos y otros han requerido el esfuerzo del capital público y privado para sacar adelante obras para embellecer y volver más atractiva a la inversión en las grandes urbes modernas del nuevo y el viejo contienente. A excepcion de las residencias para los atletas asociados a la celebración de las olimpiadas han sido pocos los proyectos, durante los últimos treinta años, que han ampliado significativamente el inventario habitacional. Por el contrario muchos de estos proyectos, de inversion y embellecimiento urbano, generan plusvalias y valorizaciones que desplazan y afectan principalmente a propietarios e inquilinos de bajos ingresos. El documento sugiere que no es suficiente la existencia de un marco institucional y una política de vivienda, sino que se requiere de una efectiva y eficiente voluntad política para ampliar las opciones de vivienda a todos los segmentos de ingresos. Adicionalmente se requiere de autoridades conocedores y receptivas que puedan ver a través del “espejismo”de las bonanzas del mercado inmobiliario, como se exasperan la condiciones de vida y se amplia la demanda de vivienda barata y asequible. Finalmente en el documento se exploran argumentos que sugieren la conveneincia de una ciudad que incluya opciones habitacionales para todas las familias e individuos trabajadores, y el buen negocio económico que representa ampliar la oferta de vivienda en propiedad o arriendo para la demanda de vivienda de las familias de ingresos medios y bajos urbanos. Finalmente el documento sugiere la razón del ser de la rama ejecutiva del gobierno. La ejecución de proyectos de inversión que mejoren la calidad de vida de los ciudadanos debe ser la referencia por la cual se evalué la gestión de los gobernantes y de las autoridades sectoriales. Basta de maquillajes políticos y manos a la obra.
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Making Housing Policy Work The Millennium Housing Project

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Imagen de apoyo de  Vapor-Liquid Equilibria measurements and  modelling of LNG multi-component mixtures including Methane, Ethane, Propane and Butane at cryogenic conditions = Mediciones del Equilibrio Liquido-Vapor y modelamiento de mezcla multicomponente de Gas Natural Licuado incluyendo Metano, Etano, Propano y Butano a condiciones criogénicas

Vapor-Liquid Equilibria measurements and modelling of LNG multi-component mixtures including Methane, Ethane, Propane and Butane at cryogenic conditions = Mediciones del Equilibrio Liquido-Vapor y modelamiento de mezcla multicomponente de Gas Natural Licuado incluyendo Metano, Etano, Propano y Butano a condiciones criogénicas

Por: Rudith Andrea; May Porras Cifuentes | Fecha: 2012

The construction of an LNG facility implies a considerable expenditure the capital, generally, the process simulators are used to estimate the operating parameters of the liquefaction plant and to size the equipment needed. Although, natural gas data has been widely studied under non-cryogenic conditions, the availability of thermodynamic data for multi-component mixtures at high pressure, and cryogenic temperatures is still poor (Laskowski L., 2008). Therefore, accurate vapour-liquid equilibria (VLE), and calorific data for multi-component mixtures at LNG process conditions would enhance the simulations.Measurements of VLE data for binary mixture consisted of methane and butane and also a multi-component mixture; methane, ethane, propane and butane were performanced. Furthermore, a comparison of these data with the predictions given by Aspen HYSYS software, using the Peng-Robinson (PR), Soave Redlich Kwong (SRK) and the GERG equations of state (EOSs). Moreover, an improvement in the performance of cubic EOSs in HYSYS is studied by anchoring these data using a tuning code. Finally, analyse the impact of those finding in the LNG scrub column.The experimental part of the project has completed using a cryogenic VLE apparatus, while the modelling part has done by using a tuning code that interacts between HYSYS and MS Excel; it optimizes an objective function by the modification of binary interaction parameters in the equation of state.
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Vapor-Liquid Equilibria measurements and modelling of LNG multi-component mixtures including Methane, Ethane, Propane and Butane at cryogenic conditions = Mediciones del Equilibrio Liquido-Vapor y modelamiento de mezcla multicomponente de Gas Natural Licuado incluyendo Metano, Etano, Propano y Butano a condiciones criogénicas

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Imagen de apoyo de  Novela y violencia en Colombia: el narcotráfico y el sicariato

Novela y violencia en Colombia: el narcotráfico y el sicariato

Por: Óscar Wilson Osorio | Fecha: 2012

In this dissertation I will analyze twenty four novels which inquire into the topics of drug trafficking and contract killings in Colombia. I will enter these novels into the widest sphere of the narrative of Colombian violence; I will discuss the denomination “sicaresca” and the approach of literary analysis to this narrative. I will also propose a definition of said literature according to the connections with socio-historical referents that their works of fiction deal with. This is necessary because some of the critical approaches to this corpus carry an inheritance of prejudices that mar these analyses. I approach this narrative through the individual analysis of each of these novels and the cross-analyses of groups of novels according to the emphasis on the topics of drug trafficking and contract killing. I find that although these corpuses (drug trafficking novels and contract killing novels) have connections most of the times, they maintain substantial differences in their understanding of the phenomena of drug trafficking and contract killings, the city-violence relationship and the configuration of delinquents and their social impact. It is necessary to take into account that the social perception of the phenomenon of drug trafficking is determined by cultural, historical and regional conditions that determine the construction of literary fictions and the perception of the world that these entail. For this, I propose a literary cartography that examines the sociocultural influences and determinations in the construction of the world that these novels perform in five regions: the Atlantic coast, Valle del Cauca, Antioquia, Eje Cafetero and Bogotá. In regard to the contract killer novels, I inquire into the construction of the figure of the assassin, the city-violence relation, the phenomena of drug trafficking and contract killings, and the implications of the narrative in the reading matter of the reality that these works of fiction put forward. Finally, I perform a reading of the novel La Virgen de los Sicarios in which I present the existence of a criminal thinking of the narrator that determines the evaluation of the world that the text proposes. At the end of this chapter, I examine the cinematographic adaptation of this novel and the deep transformations that are entailed in the construction of the learned narrator and his perception of reality.
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Novela y violencia en Colombia: el narcotráfico y el sicariato

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Imagen de apoyo de  Use of Organic Rankine Cycle (ORC) in Low Density Polyethylene Plant (LDPE) = Uso de Ciclo Organico Rankine (ORC) en una planta de Polietileno de baja densidad (LDPE)

Use of Organic Rankine Cycle (ORC) in Low Density Polyethylene Plant (LDPE) = Uso de Ciclo Organico Rankine (ORC) en una planta de Polietileno de baja densidad (LDPE)

Por: Héctor Fabián Reyes Parada | Fecha: 2013

Climate change, environmental legislation and binding targets for renewable energy, alongside an increased focus on the economic benefits of energy and fuel conservation, are driving the adoption of new technologies as sources of energy. With these dynamics, it is evident that waste heat recovery technologies can play a key role in reducing in reducing indirectly the CO2 footprint of existing fossil power generation and achievement of renewable energy targets. Since the recovered heat is effectively ‘free of charge’, there is a direct positive impact on the energy costs to the end user. This project aims to implement a Organic Rankine Cycle system in a Petrochemical plant, in this case a Low density Polyethylene Plant because is generated hug quantities of heat waste in the polymerization reaction during 8000 hours/year. Also is evaluated the Technical and economical advantages in order to check the feasibility of the implementation of Organic Rankine Cycle System in a Petrochemical Plant. The impact of this Project could give a good guide of the feasibility of the implement ORC system in Industrial process, because the most projects launched with this Technology have been usually used in Geothermal Applications.
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Use of Organic Rankine Cycle (ORC) in Low Density Polyethylene Plant (LDPE) = Uso de Ciclo Organico Rankine (ORC) en una planta de Polietileno de baja densidad (LDPE)

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Imagen de apoyo de  MIXING LEARNING, CULTURE AND USER INTERFACES: IS THERE A RECIPE FOR THAT? A cross-cultural design proposal

MIXING LEARNING, CULTURE AND USER INTERFACES: IS THERE A RECIPE FOR THAT? A cross-cultural design proposal

Por: Vanesa Yepes Serna | Fecha: 2016

The aim of this work is to propose an effective design strategy to deliver complex information to a multicultural audience. Following this notion, this project attempts to recognise how the principles of interface design and learning could be applied in cross-cultural communication. To carry out this proposal, an e-learning course aimed at international students was developed. E-learning was chosen as an ideal starting point to perform an interface analysis, as through learning effectiveness is possible to assess efficacy in communication, giving a chance to evaluate an interface design under specific parameters. To propose a method that could address this goal, it became clear that the application of a multidisciplinary approach was crucial. Therefore, the proposed design strategy seeks to find the links between interface design heuristics, learning principles and cultural factors analysing a group of 349 international students from five different nationalities registered at the Bauhaus University of Weimar (Winter Semester 2015/16). Using the design strategy detailed in this document, an interface for an e-learning course was developed and, it will be implemented in the context of a pilot test during the Summer Semester 2017.
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MIXING LEARNING, CULTURE AND USER INTERFACES: IS THERE A RECIPE FOR THAT? A cross-cultural design proposal

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Imagen de apoyo de  The Rights of Indigenous Peoples in the Light of International Human Rights Law

The Rights of Indigenous Peoples in the Light of International Human Rights Law

Por: Luisa María Villa Yepes | Fecha: 2016

In the first part of this study we are going to deal with the problem of definition of an indigenous people in order to identify the subjects of international legal protection. At a second stage it is necessary to seek possible justifications in favor of a special protection of indigenous minorities. Why shall indigenous minorities be granted a privileged status under international law?In the third part of this contribution we will focus on indigenous protection from a general human rights and anti-discrimination perspective. It has to be understood that indigenous rights are an integral part of international human rights law. However, the internal cultural and religious self-determination of indigenous peoples has to be conceived in line with the basic principles of human rights protection. Therefore, we will have to ask whether, after centuries of colonialism, human rights doctrine applies a paternalistic approach towards indigenous minorities and introduces a new kind of colonial domination.
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The Rights of Indigenous Peoples in the Light of International Human Rights Law

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