Saltar navegación e ir al contenido principal

Estás filtrando por

Se encontraron 3946 resultados en recursos

Imagen de apoyo de Effects of higher portions of variable renewable energy in electricity power systems = Efectos en los sistemas eléctricos de potencia con el incremento de energías renovables variables o intermitentes

Por: Andrés Mauricio Ríos Echeverry | Fecha: 2014

Worldwide electricity power systems are evolving from conventional/dispatchable sources to environmental friendly but Not-dispatchable renewable energy (RE) sources. This has effects on the dynamic of the system and on conventional and RE generators, electricity quality and energy cost. This research identifies the main effects of higher portions of Non-dispatchable RE based on a reference case. An MATLAB/EXCEL “ad-hoc” model has been developed. It simulates the Unit Commitment (UC) and Economic Dispatch (ED) with 10 conventional generators and one zero fuel cost RE generator (Non-dispatchable RE as “study-case” and Dispatchable RE “reference-case”). Results indicated that higher portions of Non-dispatchable RE had a swapping effect where base load units were displaced. Consequently, the system ran at lower cost-efficient point, the number of Start-ups and RE curtailment increased compared to the reference case. Furthermore, conventional generators running cost and system running cost followed the variable pattern of the Non-dispatchable RE source. Meanwhile, these costs were linked to the demand in the reference case. Ultimately, higher portions of Non-dispatchable RE made the system underperform compared to the reference case. Therefore, this incentive technology that lessen unwanted effects. Future studies shall focus on increasing the number of units and complexity of the system by using more powerful software.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis

Temas:
Otros
Ingeniería

Imagen de apoyo de Long-term Impacts of Conditional Cash Transfers on the Rural Youth: Evidence from Mexico’s Oportunidades program

Por: Irene Clavijo Muñoz | Fecha: 2012

Despite ample evidence about the short-term impacts of conditional cash transfer (CCT) programs on education and health outcomes, little is known about their long-term effects. This paper evaluates the longer-run impacts (after nearly 10 years) of Mexico’s renowned CCT program Oportunidades, on the rural youth. In particular, it examines the effects of differential exposure to the program (of 1.5 additional years) on education and employment outcomes as well as adult life-style decisions (marriage and migration). The results do not show strong evidence of significant long-term impacts on education (except for the elder youth). There is some of evidence that early exposure to Oportunidades is associated with a higher probability of engaging in certain types of jobs. However, there is no indication of a shift away from agricultural activities. Finally, there is some evidence suggesting that longer exposure to the program may cause women to delay marriage. This effect could enhance women’s possibilities of participating in the labor market (through a reduction or postponement of the domestic workload.) However, finding no significant impact on earnings or probability of employment may imply that in these poor rural communities additional human capital accumulation may not suffice to improve the productive lives of these young adults in the long-run.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis

Temas:
Otros
Ciencias sociales

Imagen de apoyo de Evaluation of Activated Carbon for Treating Heavy Metals in Aquaculture

Por: William Camargo Navarro | Fecha: 1995

Aquaculture operations over the years have suffered a dramatic change because of the increasing levels of industrial and agricultural contaminants in the aquatic environment. Several methods have been studied to reduce the negative contribution of contaminated effluents in the ecosystem. The method studied in this research was the use of activated carbon sorption as a feasible method to reduce the influent and effluent load of heavy metals and other harmful pollutants present mainly in fresh water aquaculture installations. The sorption of Cd, Cu, Ni, Hg, Pb, and phenol-based compounds was evaluated using batch adsorption isotherms and breakthrough experiments in packed GAC vertical columns. Both experimental facets are commonly used as scaling up techniques in the waste water treatment technology. Adsorption of Cd, Cu, Pb, and phenol occurred at different rates for each toxic contaminant, with Cd being the most readily adsorbed pollutant. The analytical determination of nickel and mercury presented some difficulties, possibly due to the analytical procedures followed. Analysis of the breakthrough curves for Cd, Cu, Ni, Pb and phenol, after the samples were passed through the columns showed that the concentration of all contaminants was reduced to a minimum value. These results support similar conclusions mentioned by several authors in the literature. The results of this research proved that activated carbon technology can be applied in aquaculture; its use however will be limited because of the high costs involved in design and development, particularly in large scale aquaculture practices.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis

Temas:
Otros
Agricultura

Imagen de apoyo de The American Dream’s Sojourn in Latin America: the dynamics of irregular and mixed migration flows through Ecuador and Colombia = La suspensión del sueño americano en Latinoamerica: las dinámicas de los flujos migratorios irregulares y mixtos

Por: Ursula Bianca Wagner | Fecha: 2011

Scholars generally agree that irregular migration is the direct consequence of the restrictionist and containment policies that have been used by states to keep immigrants outside their borders. This creates a dynamic that has three significant parts. First, restrictive border policies and practices drive refugees, asylum-seekers, and other migrants to resort to the use of irregular migration in order to reach their destinations. Second, the use of this type of migration, in particular the use of human smugglers, criminalizes and de-legitimizes refugees and asylum-seekers, and consequently third, this continues to legitimize states’ restrictionist practices. This dissertation argues that the dynamic described above is either 1) facilitated by media discourses and constructed to portray irregular migrants as a social and economic threat or 2) challenged by media discourses portraying irregular migrants as helpless victims. This dissertation explains the above-mentioned dynamics by examining the cases of Colombia and Ecuador and by providing a critical discourse analysis of written media in both countries.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis

Temas:
Otros

Imagen de apoyo de Attitudes towards body size and physical appearance among Colombian and American college students:A Multi-cultural Study = Actitudes hacia el tamaño del cuerpo y apariencia fisica en estudiantes universitarios Colombianos y Americanos: Un Estudio Multi-C

Por: Natalia Rojas Segura | Fecha: 2009

The current study analyzed attitudes towards size and physical appearance among four hundred and seventy Colombian and two hundred and ten American college students. The effects of gender and culture (and their interaction) on thin ideal internalization, sociocultural pressure to be thin, and body image dissatisfaction were examined in the sample. Results from the study showed that there are differences between gender and country: Colombian students perceived themselves as having a better body image overall compared to American students; females from both countries had a lower body image satisfaction compared to males. Surprisingly, males from both countries worry about their physical size and appearance. Implications for future research include validating instruments especially for a Colombian population, as well as continuing to include males in studies related to body image and eating disorders because it was found that they were also unsatisfied with their overall body image.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis

Temas:
Otros
Medicina

Imagen de apoyo de Play Methodologies = Metodologías del Juego: The Back Story

Por: Sebastian Trujillo Torres | Fecha: 2017

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis

Temas:
Arquitectura

Imagen de apoyo de Play Methodologies = Metodologías del Juego

Por: Sebastian Trujillo Torres | Fecha: 2017

This project starts with a lari. A street cart, very common in many urban contexts of India. This project begins by proposing alternatives to appropriate public spaces and offer resources to confront scarcity (while harnessing frugality). Is a proposal for moving markets; changing spaces we could dare to call moving homes. This is a project of essential, minimum design, frugal prototyping and collaborative explorations. A project of learning and sharing that, almost coincidentally, results in enquiries of architectural theory. A proposition of methodologies based on the essential action of play; of participating, negotiating and, ultimately, changing the world with small, collective gestures. A ponder into issues of knowledge production in the global south, in parallel to a political initiative of decolonizing: decolonizing the mind by structuring our own methods of thought, capitalising on our capabilities and rearranging our priorities as spatial agents. This is an inquest into the technology of jugaad -an attitude of frugal improvisation and innovation widely used in India- which accounts for great possibilities of use in the field of design, of spatial practice. A reconsideration of reutilizing those existing thought+material processes, within our field of practice. A gap in that field, in which we can play.

Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Tesis

Temas:
Otros
Arquitectura

Por: Vanessa Andrea Domínguez Bocanegra | Fecha: 2018

El presente trabajo es un proyecto de emprendimiento que nace de la tradición de la comida y sazón de una familia caldense, de ahí mismo nace su nombre 'La Herencia'. Este restaurante a domicilio quiere ingresar al mercado de las carnes a través de los pinchos y productos para asados. Para lo anterior, se realizaron estudios del macro entorno, identificando tendencias, indicadores de consumo y factores políticos, económicos, ambientales y culturales, a fin de analizar la viabilidad de dicho negocio. Se proyecta que en el año 2019 'La Herencia' alcance una imagen reconocida por su nicho de mercado y sea el restaurante a domicilio preferido de los caldenses en Bogotá para realizar sus asados con amigos y familiares, generando una conexión emocional con un sentimiento de añoranza por la sazón caldense y los momentos para compartir. El enfoque de marketing estratégico de La Herencia nos ayudara a estar atentos a tendencias para actuar de manera oportuna y proactiva, como, por ejemplo, iniciar nuevos servicios de asados a domicilios y ampliar su portafolio de productos como de frutas, quesos, vegetales y frutos del mar, actividades que también requieren alta inversión en investigación y desarrollo para mejorar de manera continua.

Fuente: Universidad Externado de Colombia Formatos de contenido: Tesis

Temas:
Otros
Administración

Por: Natalia Guevara Pachón | Fecha: 2020

El proyecto Redes Colaborativas en Barrio Minuto de Dios "Tejiendo en Red Sostenibilidad y Convivencia", busca crear redes comunicativas que contribuyan a mejorar la convivencia ciudadana en el barrio Minuto de Dios usando la oferta cultural que se encuentran en el lugar. la cual pertenece a la Corporación que lleva el mismo nombre del barrio, para esto se busca mejorar los lazos de comunicación que existen entre las diferentes entidades culturales de la Corporación Minuto de Dios. Mediante estrategias colaborativas como; mesas de trabajo mensuales las cuales ayuden a tener lazos permanentes y directos entre el personal administrativo de las instituciones. Para generar una red interna que contribuya a la formación de redes externas que permitan crear nuevos espacios de integración entre los habitantes del barrio Minuto de Dios, con la finalidad de fomentar la convivencia ciudadana mediante el fortalecimiento de la oferta cultural que se encuentra en el lugar.

Fuente: Universidad Externado de Colombia Formatos de contenido: Tesis

Temas:
Administración
Otros
Tecnología
Museos

Por: Lady Johanna González Tibocha | Fecha: 2020

El Observatorio Astronómico Nacional (OAN) sede histórica es una institución de carácter patrimonial que está a cargo de la Facultad de Ciencias de la Universidad Nacional de Colombia. Es considerado como la cuna de la actividad científica del país, ya que fue el primer edificio construido para este fin en el marco de la primera empresa científica de la Nueva Granada. Actualmente, el OAN sede histórica cuenta con una de las colecciones museográficas más importantes de la Universidad Nacional y del país, en materia de ciencia y específicamente de astronomía, dentro de las cuales es posible encontrar instrumentos científicos, libros de ciencia, material mueble, obras de arte y archivos, los cuales no han sido aprovechados dado el restringido acceso al edificio por encontrarse en los predios de la Casa de Nariño, la escasa asignación de recursos y la falta de articulación con dependencias de la universidad para fortalecer los trabajos en esta sede. Dado lo anterior, se plantea la formulación de un Plan de Renovación Integral que permita fortalecerlo en su dimensión institucional, científica y patrimonial, a través de la reactivación de sus colecciones y puesta en marcha de acciones de apropiación social del conocimiento científico.

Fuente: Universidad Externado de Colombia Formatos de contenido: Tesis

Temas:
Otros