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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Computer Model to Estimate Commercial Aviation Fuel Consumption and Emissions in the Continental United States

Zou, Zhihao 03 January 2013 (has links)
A comprehensive model is developed to estimate and predict the fuel consumption and emissions by domestic commercial aviation in the Continental United States. Most of the existing fuel consumption and emission models are limited in their ability to predict the annual fuel burn for air transportation at the national level. For example, those models either require real track data or are developed only to model single flight scenarios.  The model developed in this thesis is part of a software framework called the Transportation Systems Analysis Model (TSAM). The model has the capability to estimate fuel consumption and emissions for millions of domestic flights in a year in the continental U.S. TSAM is a nationwide, long-distance, multimodal travel demand forecast model developed at Virginia Tech. The model enables TSAM to quantify fuel and emission metrics for various modes of transportation. The EUROCONTROL Base of Aircraft Data (BADA) is employed as the Aircraft Performance Model to simulate individual flight profiles and calculate fuel burn rates. Fuel consumption on the ground (taxi mode) is estimated separately. Different operational conditions like wind states, terminal area detour, cruise altitude and airport elevation are considered in the model. Emissions of HC, CO, NOx and SOx are computed inside the Landing/Take-off (LTO) cycle based on the fuel consumption estimate, while greenhouse gas of CO2 is calculated for the complete flight cycle. / Master of Science
2

Vetenskaplig publicering i förändring : En fallstudie av en svensk högskolas implementering av ett öppet digitalt arkiv / Scholarly publishing in transformation : A case study of the implementation of an institutional repository at a Swedish university college

Thorsson, Anna, Zhou, Xi Ha Dan January 2008 (has links)
Since the beginning of the 21st century the Open Access-movement, which advocates free online distribution of scholarly information, has gained momentum. Authors can provide Open Access to their work in two main ways: by depositing a copy of their research output in an e-print archive and by publishing in Open Access journals. During the past few years, universities and other research institutions throughout the world have established institutional repositories to manage, preserve and provide access to the intellectual output of the university/research institution. The purpose of this master’s thesis is to describe the implementation of an institutional repository at the Swedish University College of Borås. The thesis also aims to describe the current situation regarding Open Access at the university college. The case study indicates that a requirement for the deposit of references into the repository is believed to have had a significant impact on the contents of the institutional repository. The full-text availability of research publications is, however, at present relatively low. The results show that there are three main barriers in the development of the institutional repository: lack of knowledge regarding Open Access and digital publishing, copyright issues and lack of time. Misconception and uncertainty regarding the guarantee of quality of the digital material are factors that most likely prevent researchers from depositing their research articles into the institutional repository. Librarians play a key role when it comes to informing about self-archiving and Open Access. Our conclusion is that to obtain more research publications in full-text, researchers need to gain more knowledge about institutional repositories and digital publishing. / Uppsatsnivå: D
3

A Process for the Quantification of Aircraft Noise and Emissions Interdependencies

de Luis, Jorge 05 May 2008 (has links)
The main purpose of this dissertation is to develop a process to improve actual policy-making procedures in terms of aviation environmental effects. This research work expands current practices with physics based publicly available models. The process herein proposed provides information regarding the interdependencies between the environmental effects of aircraft. These interdependencies are also tied to the actual physical parameters of the aircraft and the engine, making it more intuitive for decision-makers to understand the impacts to the vehicle due to different policy scenarios. These scenarios involve the use of fleet analysis tools in which the existing aircraft are used to predict the environmental effects of imposing new stringency levels. The aircraft used are reduced to a series of coefficients that represent their performance, in terms of flight characteristics, fuel burn, noise, and emissions. These coefficients are then utilized to model flight operations and calculate what the environmental impacts of those aircraft are. If a particular aircraft does not meet the stringency to be analyzed, a technology response is applied to it, in order to meet that stringency. Depending on the level of reduction needed, this technology response can have an effect on the fuel burn characteristic of the aircraft. The proposed alternative is to create a fleet of replacement aircraft to the current fleet that does not meet stringency. These replacement aircraft represent the achievable physical limits for state of the art systems. In addition, the replacement aircraft show the linkage between environmental effects and fundamental aircraft and engine characteristics, something that has been neglected in previous policy making procedures. Another aspect that has been ignored is the creation of the coefficients used for the fleet analyses. In current literature, a defined process for the creation of those coefficients does not exist, but this research work develops a process to do so and demonstrates that the characteristics of the aircraft can be propagated to the coefficients and to the fleet analysis tools.

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