1,720,961 research outputs found
Desarrollo de una herramienta en excel para la evaluacion de procesos de manufactura de productos de aluminio utilizando un enfoque de sostenibilidad
Get PDFEn el proceso de manufactura de aluminio, cada una de las etapas es significativa, algunas de ellas más complejas, en las cuales el consumo de energía eléctrica es representativo. Esto conlleva al aumento de emisiones al ambiente debido a su relación directa. Por tal motivo, es importante diseñar los procesos de manufactura lo más sostenibles posibles. Teniendo en cuenta que el aluminio es un material totalmente reciclable, en este trabajo se desarrolla una herramienta computacional, como estrategia que permita considerar aspectos relevantes como las emisiones y la viabilidad económica, apoyando el proceso de toma de decisiones en la manufactura del aluminio. En esta tesis de Maestría se presenta una herramienta computacional en Microsoft Excel® que apoya la toma de decisiones en los procesos de producción de aluminio, utilizando un enfoque de sostenibilidad ambiental y económica. La aplicación de la herramienta permite hacer un análisis completo de cada uno de los procesos en términos ambientales y económicos con el fin de obtener un sistema sostenible.Magíster en Gestión Energética Industria
Techno-economic and environmental risk assessment of innovative propulsion systems for short-range civil aircraft
Get PDFAircraft are thought to contribute about 3.5% (IPCC, 1999) to the total radiative
forcing (a measure of change in climate) of all the human activities and this figure
is forecaste to increase. Future concerns for aviation’s role in climate change are
mainly due to the envisaged continued growth in this sector. Growth rates for
emissions are less than those for traffic growth since fuel efficiency continues to
improve over the years. Despite regular improvements in fuel efficiency, emissions
will carry on increasing and several solutions need to be found.
The growth of air travel as well and its effect on world economics is hampered by
local opposition to aircraft noise. Besides, restrictions on night take-off and landing
because of aircraft noise levels leads to a negative impact on the revenues of
Europe’s airlines and often results in non-European over-night airport refuelling
stops.
According to ACARE (Strategic Research Agenda, 2005), the sustainable
development of air transport depends on achieving a significant across-the-board
reduction in environmental impact, in terms of greenhouse gases, local pollution
and noise around airports. Over the past 40 years the introduction of new
technology has mitigated the environmental impact of aviation growth, but at the
expense of increasing operating costs. Consequently, in order to make aviation
more sustainable environmentally and economically, radically innovative turbofans
need to be considered and optimised at the aircraft level. Based on the above, this PhD project addresses the following research questions:
• The potential of different novel propulsion systems with enhanced
propulsive efficiency (using advanced, contra-rotating and geared
turbofans) and thermal efficiency (using intercooled and recuperated, and
constant volume combustion turbofans) to meet future environmental and
economical goals.
• The trade-offs to be made between noise, emissions, operating cost, fuel
burn and performance using single- and multi-objective optimisation case
study.
In order to achieve this, a multidisciplinary design framework was developed which
is made up of: aircraft and engine performance, weight, cost, noise, emissions,
environment, and economics and risk models. An appropriate commercially
available optimiser is coupled with this framework in order to generate a powerful
aero-engine preliminary design tool.
The innovative turbofans were benchmarked against the baseline turbofan at the
aircraft level using the A320. The multi-objective trade case study for minimum fuel
burn, NOx emissions, engine direct operating cost (DOC) and noise proves that
these engines are feasible to meet future noise and emissions requirements for an
acceptable cost of ownership. The key driver to lower engine DOC is a
considerable fall in fuel consumption. Nevertheless, acquisition and maintenance
cost rise owing to hardware complexity. Consequently, further study of these
engines is recommended as their environmental performance potential is
considerable
Diseño de planta de energía virtual para control y administración de plantas e infraestructura energética renovable en el entorno colombiano
No full textA continuación, se presenta el desarrollo del trabajo de grado titulada “Diseño de planta de energía virtual para control y administración de plantas e infraestructura energética renovable en el entorno colombiano”, para optar al título de Máster en Gestión de Tecnologías de la Información. En este proyecto se describen algunas de las necesidades que se presentan en las infraestructuras y distribución de producción de energías renovables en lo referente a su supervisión y gestión.
Como proyecto se planteó generar un diseño de una Planta de Energía Virtual, para la administración de plantas e infraestructuras de generación de energías renovables, con la construcción de un algoritmo que permite revisar e interrelacionar las condiciones ambientales, que puedan afectar la generación de las diferentes plantas y la demanda de energía, simulada en diferentes escenarios como alta demanda / baja oferta (generada por condiciones ambientales), alta demanda / baja oferta (por afectación en infraestructura), alta oferta / baja demanda, en Colombia.
En este proyecto se realiza un trabajo con modelos lineales de optimización y el uso de modelos PSO (Particle Swarm Optimization), construidos bajo la plataforma de Matlab.Introducción. -- 1. Planteamiento del Problema. -- 2. Justificación. -- 3. Objetivos. -- 3.1. Objetivo General. -- 3.2 Objetivos Específicos -- 4. Marco teórico. -- 4.1 Estado del Arte. -- 4.1.1 Ámbito Internacional. -- 4.1.1.1 Optimización -- 4.1.1.2 Plantas de energía virtual (VPP): -- 4.1.1.3 VPP-Optimización: -- 4.1.2 Entorno colombiano -- 4.1.2.1 Optimización -- 4.1.2.2 VPP -- 4.2 Marco conceptual -- 4.2.1 Optimización -- 4.2.2 Internet de las cosas IoT -- 4.2.3 Arquitectura BluePrint IBM -- 4.2.4 Smart Grid -- 4.2.5 SCADA -- 5. Metodología -- 5.1 Marco conceptual -- 5.2 Instrumentos -- 5.2.1 Análisis Documental -- 5.3 Procedimiento -- 5.3.1 Objetivo 1: Revisar del estado del arte y literatura sobre las plantas de energía virtual VPP (Virtual Power Plant) -- 5.3.2 Objetivo 2: Definir los requerimientos para el diseño de la planta de energía Virtual VPP. -- 5.3.3 Objetivo 3: Diseñar una planta de energía virtual de acuerdo con los requerimientos definidos que permita administrar diferentes infraestructuras independientes de energías no convencionales en Colombia. -- 5.3.4 Definir un algoritmo de control de distribución de carga energética y suministro por infraestructura dependiendo de condiciones ambientales y demanda de energía. -- 5.3.4.1 Algoritmo Lineal por Área -- 5.3.4.2 Algoritmo PSO por Área: -- 5.3.4.3 Algoritmo Lineal Multi-Area: -- 5.3.4.4 Algortimo PSO Multi Area -- 5.3.5 Validar el algoritmo desarrollado por medio de simulaciones para identificar la eficiencia del algoritmo -- 6. Resultados -- 6.1 Resultados algoritmo -- 6.1.1 Algoritmo lineal <= demanda -- 6.1.2 Algoritmo lineal = demanda. -- 6.1.3 Algoritmo PSO <= demanda. -- 6.1.4 Resumen Tiempos Por Área -- 6.2. Resultados algoritmo Multi-área. -- 6.2.1 Tiempos de respuestas Algoritmos para la configuración Multi-área. -- 6.3 Evaluación de los algoritmos. -- 7. Conclusiones. -- 8. Discusión – Referencias. -- Apé[email protected]
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Techno-economic and environmental risk assessment of innovative propulsion systems for short-range civil aircraft
Get PDFAircraft are thought to contribute about 3.5% (IPCC, 1999) to the total radiative forcing (a measure of change in climate) of all the human activities and this figure is forecaste to increase. Future concerns for aviation’s role in climate change are mainly due to the envisaged continued growth in this sector. Growth rates for emissions are less than those for traffic growth since fuel efficiency continues to improve over the years. Despite regular improvements in fuel efficiency, emissions will carry on increasing and several solutions need to be found. The growth of air travel as well and its effect on world economics is hampered by local opposition to aircraft noise. Besides, restrictions on night take-off and landing because of aircraft noise levels leads to a negative impact on the revenues of Europe’s airlines and often results in non-European over-night airport refuelling stops. According to ACARE (Strategic Research Agenda, 2005), the sustainable development of air transport depends on achieving a significant across-the-board reduction in environmental impact, in terms of greenhouse gases, local pollution and noise around airports. Over the past 40 years the introduction of new technology has mitigated the environmental impact of aviation growth, but at the expense of increasing operating costs. Consequently, in order to make aviation more sustainable environmentally and economically, radically innovative turbofans need to be considered and optimised at the aircraft level. Based on the above, this PhD project addresses the following research questions: • The potential of different novel propulsion systems with enhanced propulsive efficiency (using advanced, contra-rotating and geared turbofans) and thermal efficiency (using intercooled and recuperated, and constant volume combustion turbofans) to meet future environmental and economical goals. • The trade-offs to be made between noise, emissions, operating cost, fuel burn and performance using single- and multi-objective optimisation case study. In order to achieve this, a multidisciplinary design framework was developed which is made up of: aircraft and engine performance, weight, cost, noise, emissions, environment, and economics and risk models. An appropriate commercially available optimiser is coupled with this framework in order to generate a powerful aero-engine preliminary design tool. The innovative turbofans were benchmarked against the baseline turbofan at the aircraft level using the A320. The multi-objective trade case study for minimum fuel burn, NOx emissions, engine direct operating cost (DOC) and noise proves that these engines are feasible to meet future noise and emissions requirements for an acceptable cost of ownership. The key driver to lower engine DOC is a considerable fall in fuel consumption. Nevertheless, acquisition and maintenance cost rise owing to hardware complexity. Consequently, further study of these engines is recommended as their environmental performance potential is considerable.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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