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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

APPLICATION OF DISTRIBUTED GENERATION SOURCES FOR MICRO-GRID POWER QUALITY ENHANCEMENT

Rafiei, Sepide 03 February 2014 (has links)
In conventional power generation systems, large centralized plants operating on fossil fuel mainly generate the electric power. The generated electricity has to travel through the long transmission and distribution lines to be delivered to the end users. In addition to being costly, this structure yields poor reliability and low efficiency. On the other hand, serious concerns have been raised about the shortage of fossil fuels, global warming, and energy security. As a result, the power systems are moving toward more distributed structures based on renewable energy resources. During the last decade, the concept of small-scale energy resources distributed over the grid has gained a considerable interest. This concept is often called distributed generation (DG). DG systems are mainly using renewable energy sources as their prime movers. Renewable energy sources (including biomass, wind, solar, hydropower, and geothermal) can provide clean, efficient, reliable and adequate energy supply while making modern energy services accessible and affordable. However, despite the substantial benefits of distributed generation, the application of an individual DG system can cause as many problems as it may solve. To avoid such problems and to realize the emerging potential of distributed generation, a system approach has been taken, in which generation and loads are considered as a subsystem called “micro-grid”. One important issue in the existing power network is the capability of renewable energy sources to increase the power quality of the micro-grid. One aspect of this feature is harmonic compensation using distributed resources. In this thesis an adoptive notch filter (ANF) is employed in the control system of a distributed generation (DG) system for harmonic compensation. It is shown that the performance of the system is highly improved using the adoptive notch filter. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2014-02-01 08:16:28.205
2

TASK DESCRIPTIONS OF NON-WESTERN ENGLISH LANGUAGE USE

Lanteigne, Betty 08 April 2005 (has links)
Many English tests and texts based on Western culture are inappropriate for regions where English use differs from that of Europe and North America. In these non-Western settings, it is desirable that English instruction and assessment be based on real-world English use. / Mike Williamson
3

Transcendence

Klinke, James 05 December 2012 (has links)
Artist Statement I have often created art with an organic quality because I have felt bound by the earth’s natural elements and forces. These extend to and influence my human qualities which influence my artwork. My paintings and mixed media works symbolize the issues and defects that affect me in various ways and represent my attempt at overcoming them. At its core, my body of work addresses psychological and emotional recovery work. I have been burdened for a long period of time with anxiety, various character defects, and difficulties but I find catharsis through creative expression. Because I have chosen to address and convey my on-going struggle for emotional well-being in my work, I depict distorted images which I sometimes describe as ghostlike figures. These images symbolize the issues and defects that often have a negative impact on my life. However, in many ways, these images also symbolize to me the gratitude I feel for overcoming such trying times. For without these psychological and emotional trials and tribulations, I would not be the person I am at this point in my life. I now possess the tools I need to develop a healthier quality of life. My experiences are reflected in my works.
4

Predicting drag losses & oil flow characteristics in a wet clutch system using numerical analysis

Liljegren, Marcus, Ljeskovica, Edin January 2016 (has links)
This report presents the Master Thesis done by two students at the Mechanical Engineering program, Design Engineering at Luleå University of Technology. The thesis was performed at Luleå University of Technology in collaboration with BorgWarner PDS located in Landskrona. The objective for the thesis was to study the potential for predicting and optimizing drag losses and oil flow characteristics in a wet clutch system using numerical simulations in LS-DYNA. BorgWarner PDS manufactures and distributes the Haldex coupling, which is an electro-hydraulic coupling used in an active four-wheel drive system. BorgWarner PDS strives to make the Haldex coupling more efficient by minimizing energy losses in order to lower fuel consumption for the vehicle and a smaller impact on the environment. As testing on prototypes are costly and time consuming it is therefore desirable to use numerical simulations instead. To determine the potential for numerical simulations to predict and optimize both drag losses and oil flow characteristics a numerical model was set up using LS-DYNA. A test rig was designed in order to achieve a controlled testing environment in order to validate the numerical models, both qualitatively and quantitatively. The numerical model uses the built in Fluid Structure Interaction method in LS-DYNA, which is a combination of a structural model and an incompressible fluid model. The test rig measures torque on the clutch housing induced by the dragging of oil as the clutch drum rotates. The tests were performed using different rotational speeds, varying from 250-1500 rpm, and different clutch housing geometries. The results were gathered from an average of ten measurements of the drag torque. A high- speed camera was also used to capture the oil flow characteristics. The numerical simulations were done using the same parameters used for the tests i.e. different rotational speeds and clutch housing geometries. In addition, each simulation was performed using different mesh sizes; 0.5 mm, 1 mm and 2 mm in order to analyze mesh dependence. The numerical model was set to measure the drag torque on the clutch drum and was then compared to the experimental results in order to validate the numerical model quantitatively. The oil flow characteristics from the numerical simulation were compared to the high-speed movies to validate the numerical model qualitatively. The numerical model shows promising results when it comes to predicting drag torque and oil flow characteristics. The results also show that using a numerical model for optimization purposes are possible as the experimentally measured drag torque at different clutch house geometries corresponds to the numerically simulated drag torque. The conclusions from this Master Thesis is that numerical simulations do have a potential for predicting drag losses and oil flow characteristics in a wet clutch system. The numerical model created in this project can also be used to obtain valuable information about geometry changes when it comes to optimizing the wet clutch system. However, the numerical model is still at an early stage and can be seen as a second generation model where further work needs to be done in order to include more of the complex geometries of a wet clutch system have. Although LS-DYNA is state-of-the-art when it comes to these kinds of complex simulations it still needs to be developed further to handle such complex simulations.
5

Metal-catalysed synthesis in the presence of boronates

Ma, Ming Ju January 2014 (has links)
This thesis describes the use of alcohols as alkylating agents for the formation of new C-C and C-N bonds and the development of new, advantageous, catalytic syntheses of boronic acid compounds.
6

Either side of a line

White, Lowell Mick 29 August 2005 (has links)
This collection of original short stories with a critical introduction has been written as a summary and capstone of my study of creative writing at Texas A&M University. The introduction explores the nature and development of short fiction, the influences on my writing, and attempts to place my stories within the context of short fiction and Texas fiction. The stories deal with aspects of life in early 21st Century Texas ?? a complicated time of boom and bust, of love and fear, of dislocation and greater dislocation.
7

An economic analysis of regulation by conditional permits /

Lenntorp, Erik. January 2006 (has links) (PDF)
Univ., Diss.--Linköping, 2006.
8

A hermeneutical and phenomenological investigation into the epoche as lived experience in existential phenomenological psychotherapy

Wasz, Margaret January 2010 (has links)
This study is an exploration of the epoche as a lived experience in existential phenomenological psychotherapy. Beginning with the philosophical underpinnings of the epoche the study explores Husserl's writings regarding the epoche and his reason for introducing the epoche to the practice of phenomenology. A phenomenological · approach to method is used, namely Van Manen's hermeneutic interpretive phenomenology. Using this method, data was generated from ten interviews with existential phenomenological psychotherapists. The focus of the interviews was how the epoche was experienced in practice as a lived experience and how it was effected, this included the procedures used to help effect the epoche and the struggle to maintain the epoche against the pull of the natural attitude. To further explore and understand the epoche I include a piece on my research journey and a personal lived experience in effecting the epoche. Using three stages, thoughtfulness, thematic analysis and seeking meaning, the data is analyzed and from here the themes emerge. The interpretations emerge out of these phenomenological themes and are contrasted and compared with existing concepts in existential phenomenological philosophy, and with current multidisciplinary thought highlighting preliminary possibilities for reconfiguring existing approaches to the epoche. This thesis argues that the coresearchers using other approaches such as mindfulness inadvertently find a way of effecting the epoche and that the mistrust and difficulties co-researchers experience with regard to the epoche is based on misconceptions regarding the epoche, misconceptions which crossed over from phenomenological philosophy to phenomenological psychotherapy. There is also the issue of the lack of instruction in how to perform the epoche. As a consequence the epoche is only partially appreciated and it is to this end that this study might bring into view the relevance and remit of the epoche not only in existential psychotherapy but in using the epoche in any phenomenological investigations.
9

Towards an analytical framework for privacy-preserving aggregation in smart grid

Alamatsaz, Navid Reza 05 1900 (has links)
Recent changes to the power grid are expected to influence the way energy is provided and consumed by customers. Advanced Metering Infrastructure (AMI) is a tool to incorporate these changes for modernizing the electricity grid. However, this information-based power grid can reveal sensitive private information from the user's perspective as it can gather highly-granular power consumption data. This has led to limited consumer acceptance and proliferation of the smart grid. Hence, it is crucial to design a mechanism to prevent the leakage of such sensitive consumer usage information. Among different solutions for preserving consumer privacy in Smart Grid Networks (SGN), private data aggregation techniques have received a tremendous focus from security researches. In this work, a novel and efficient CDMA-based approach to privacy-preserving aggregation in SGNs, utilizing random perturbation of power consumption data, with limited use of traditional cryptography has been presented. The efficiency and performance of the proposed privacy-preserving data aggregation scheme is evaluated and validated through extensive statistical analyses and simulations. In the past few years, only limited work has been done on quantifying the privacy leakage of the smart grid due to the deployment of the smart meters. The goal of such quantification is to provide a formal framework to show how much privacy is lost in smart metering systems and to what extent the proposed solutions reduce this loss of privacy. As a second research direction, we study the existing metrics for quantifying privacy in various domains. Then, we present four information theoretic metrics to represent the privacy gained by utilizing different Smart grid Privacy Preserving Mechanisms (SPPMs). We investigate the applicability of the theory of information entropy as a potential privacy metric and suggest using conditional entropy, joint entropy, and relative entropy to further analyze the privacy-leakage in smart metering systems. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science
10

Etched into history: Analysis of male and female portrayals in American films between 1950-2012

Bocchino, Hulda 05 1900 (has links)
As the medium of film has become ubiquitous, it has become an influential vehicle for the transmission of gender-related values. Because gender portrayals in popular entertainment film play a role in the formation of social identity, and can affect human behavior, this thesis studies a group of popular American entertainment film's portrayals of their male and female characters. The method used to study the films, which were selected from the years 1950-2012, utilizes qualitative content analysis. The findings suggest that the female characters within the films studied broke old gender stereotypes more consistently than did their male characters. That said, there was some progress in terms of how some of the later films portrayed their primary male characters. / Thesis (M.A.)--Wichita State University, Fairmount College of Liberal Arts and Sciences, Dept. of Communication

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