Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 251-254).

No description available.

The advent of Wide-Area measurement Systems has spurred interest in the use of non-local feedback signals for power swing damping control. Although damping can be improved through generator excitation systems, dc links and other grid connected power electronic converters, the full potential of wide-area measurements can be realized by coordinating the strategies used for multiple controllable devices in a grid. These strategies also need to be robust to partial or complete loss of communication, changes in operating points, topology and equipment outages, improve damping of all the controllable swing modes, and have adequate stability margins to avoid destabilization of untargeted modes. This thesis investigates a control strategy for multi-infeed and multi-terminal (also referred to as multiple embedded dc links in this thesis) dc links using local frequency difference signals as well as the frequency difference signals obtained from other dc links. This strategy combines the advantages of the local frequency difference signal with the additional degrees of freedom provided by the use of non-local frequency difference signals, to achieve targeted and enhanced swing mode damping for the poorly damped modes. Since the strategy uses only a limited set of non-local signals, the signals may be directly communicated to the dc links without having to be centrally collated with other system-wide measurements. The key aspect of the proposed strategy is the use of a symmetric positive definite (spd) gain matrix. This results in enhanced damping for all controllable swing modes. Furthermore, loss of communication between the dc links does not destroy the symmetric positive definiteness and the gain elements can be tuned to selectively enhance damping of poorly damped modes. Eigenvalue sensitivity analysis and case studies on a 3 machine 9 bus and 16 machine 68 bus system with multiple HVDC links are presented to demonstrate the key attributes and the effectiveness of this strategy. / October 2016

Thesis (Ed. D.)--Illinois State University, 1982. / Title from title page screen, viewed April 13, 2005. Dissertation Committee: Max Rennels (chair), Macon Williams, Gordon Redding, Heather Hanlon, Richard Hentz, Robert Stefl. Includes bibliographical references (leaf 27) and abstract. Also available in print.

Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Elizabeth M. Jakubowski, Florida State University, College of Education, Dept. of Middle & Secondary Education. Title and description from dissertation home page (viewed Sept. 19, 2006). Document formatted into pages; contains xiii, 219 pages. Includes bibliographical references.

The research problem reported in this thesis is an investigation of the teaching and learning of area measurement in the early years of school. Research indicates that children confuse the measurement of area and perimeter and also the use of linear and two-dimensional units of measure. The first phase of the study investigated the knowledge and skills which underpin an understanding of the L x B formula for calculating rectangular area. Those factors were used to plan a teaching program of four lessons for Year 1 and Year 2 children, focusing on: establishing the attribute of area; making, describing and drawing the spatial structure of arrays of repeated informal units to measure areas; and methods of counting to determine the total number of units. The effectiveness of the program was evaluated by implementing the lessons in four classes. Lessons planned from the then current syllabus were implemented in another four classes. Comparison of student learning outcomes from all classes indicated that the research lessons were more effective in assisting children to develop an understanding of a grid pattern or array of repeated informal units. The second phase of this study described the researcher’s investigation, design and trial of teacher professional learning strategies which would assist teachers to adopt successful methods of teaching young children to measure area. Seventeen volunteer teachers in seven school teams participated in one of three models of professional learning, based on varying levels of consultancy support. The models were based on the provision of lesson notes and teaching materials, facilitation of team meetings to discuss the implementation, and the provision of additional time to interview individual children following each lesson. Participation in the project assisted all of the participating teachers to develop their content knowledge and to modify their teacher-centred teaching practices. The key strategies and factors which contributed to this success included ongoing school based professional dialogue and support, the provision of a teaching program which emphasised students’ conceptual development within a sequence of activities, the role played by teacher leaders within each team, opportunities to develop questioning techniques and the motivation and disposition of the participating teachers.ABSTRACT / Doctor of Philosophy (PhD)

Thesis (Ph.D.)--University of Western Sydney, 2007. / "A thesis submitted to the University of Western Sydney, College of Arts, School of Education in fulfilment of the requirements for the degree of Doctor of Philosophy." Includes bibliography.

Due to the spread of urbanisation and increased environmental awareness, odour has become a major problem in communities surrounding landfills. The aim of this research was to investigate odour emissions from landfills and develop a management tool that operators could use to assist in minimising the impacts of odour. The management tool would be in the form of real-time predictions of odour concentrations in the vicinity of a source. The Bisasar Road landfill in Springfield, Durban was a case study site for the research. The methodologies used in this project can be divided into three broad categories. Firstly, flow visualisation experiments were conducted on the case study site to investigate the effects of complex terrain and the results compared to predictions from a dispersion model. Secondly, source characterisation was done on-site. Sources of odour were identified using a portable odour monitor (Electronic nose). Sources of odour were then sampled using sorbent tubes and analysis done using Gas Chromatography - Mass Spectrometry. Thirdly, numerical dispersion modelling was done. Five available dispersion models were assessed and compared against one another in order to select the most suitable model for this application. A software management tool or 'Odour Management System' (OMS), was designed and implemented on a computer at the Bisasar Road landfill. Qualitative results of the flow visualisation experiments show that terrain does have an effect on a dispersing plume path for short-range predictions. Comparisons between the flow experiments and model predictions are qualitatively consistent. Quantitative results were not obtained for the emission flow rate and emission concentration of landfill gas. The chemical composition of the fresh waste gas was determined. ADMSTM(Advanced Dispersion Modelling System) was found to be the most suitable dispersion model for this application. The OMS has been installed on-site to produce odour concentration graphics every ten minutes. A fence line odour control misting system has been installed along approximately 600 metres of the landfill border based on work done as part of this project. Weather conditions and information provided by the OMS, assist in running the odour control system economically. / Thesis (M.Sc.Eng.)-University of Natal,Durban, 2002.

Landfill gas (LFG) contributes significantly to air pollution. Methane (CH4) and carbon dioxide (CO2) are the major constituents of LFG, and are significant greenhouse gases that play a vital role in causing global warming. Certain air pollutants from landfill sites are carcinogenic (e.g. benzene), while others are odorous (e.g. methyl mercaptan). Due to these potential negative impacts, there is need to forecast the yield and production rate of biogas generated. Limited work has been done on the modelling of LFG emissions for landfill sites in Durban. This study focuses on the estimation of air pollutant emissions from three landfill sites, namely Bisasar Road, Shongweni and Buffelsdraai using the LANDGEM model and comparing the results against the findings of Hofstetter Gas Yield Model which has been utilized before by Durban Solid Waste (DSW) for Bisasar Road landfill. The greenhouse gases of global concern, namely CH4, CO2 and halocarbons were investigated in this study. The LANDGEM model predicted CO2 emissions to be higher than CH4 and other greenhouse gases. The warm, moist climatic conditions suitable for CH4 oxidation may be responsible for the increased generation rates of CO2. The main components of LFG which cause landfill odour problems are sulphur-containing compounds. Methyl mercaptan is the component causing persistent bad odours in the landfills, contrary to popular belief that hydrogen sulphide is the major contributor to odour pollution. Hydrogen sulphide has been predicted by LANDGEM to be the sulphur-containing gas that is produced in greatest quantities. Benzene and vinyl chloride are the most hazardous compounds emitted from landfills, since they are carcinogenic. The emission rates of benzene were found to be higher than those of vinyl chloride in the active landfill sites of Bisasar Road and Shongweni. The LANDGEM model estimated total LFG emissions of 8.371 x 107 m3y-1 at Bisasar Road landfill, compared with a lower emission rate of 3.285 x 107 m3y-1 predicted by the Hofstetter model. The LANDGEM model revealed LFG to peak during the closure of the landfill, and to decline thereafter for a long period of time. The Hofstetter model showed that LFG could reach its maximum within three years of waste deposition. LANDGEM model is a widely used methodology for estimating LFG emissions. It is used in United States as regulatory model to quantify the potential LFG emissions produced from the landfill. This model can be used by landfill owners and operators to evaluate the performance of the landfill and to determine whether the landfill is still subject to regulatory requirements, especially in the countries where emission guidelines have been established. Therefore, in the developing country like South Africa, it is essential to quantify and evaluate the LFG emissions released from landfills despite the fact that no legal LFG emission guidelines are put in place yet. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

Made available in DSpace on 2014-06-11T19:31:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-15Bitstream added on 2014-06-13T19:42:02Z : No. of bitstreams: 1 silva_eg_dr_botfca.pdf: 1092618 bytes, checksum: 2cecd410091c2837654b5683e84fd1b8 (MD5) / O desenvolvimento da agricultura e o uso da terra de maneira não somente a protegê-la contra alterações superficiais provocadas pela ação constante dos fenômenos naturais, mas também a desenvolver aos poucos sua capacidade produtiva, requer um cuidadoso planejamento inicial. Para que o mesmo seja efetivo e eficiente, é necessário que se tenha acesso a informações corretas e detalhadas, as quais podem estar disponíveis em imagens aéreas de sensoriamento remoto. O uso das fotografias aéreas verticais dentre os produtos do Sensoriamento Remoto se tornou cada vez mais frequente nos projetos de levantamentos, planejamentos e explorações do solo, principalmente porque substitui, com vantagens, outras bases cartográficas, além da riqueza de detalhes que oferece, eliminando-se assim as dificuldades de acesso em áreas inacessíveis, bem como facilitando a visão tridimensional, por aumentar o rendimento e a precisão do mapeamento, por meio da combinação dos trabalhos de campo e laboratório, com o estudo de interpretação fotográfica. Este trabalho utilizou-se de fotografias aéreas pancromáticas nas escalas nominais 1:25000 (1962), 1:45000 (1977) e coloridas na escala nominal aproximada de 1:30.000, proveniente do levantamento aerofotogramétrico efetuado no ano de 2005, tendo como objetivo mostrar através da utilização de um Sistema de Informação Geográfica (SIG) a possibilidade de realizar uma análise mais completa e segura de valores de área, obtidos diretamente na foto sem correções de escala, e posteriormente compará-los com os valores de área obtidos de fotografias aéreas com escalas corrigidas, tendo como referência a carta do Instituto Geográfico e Cartográfico do Estado de São Paulo, resultando num coeficiente de erro que mostrará as diferenças das áreas através... / interpretation is a basic resource and it constitutes in a technique which enables infinite refining. Agricultural development and ground use requires a careful initial planning in order not only to protect them against superficial changing provoked by natural phenomena but also to gradually develop its productive capacity. For the efficiency of ground management, it is necessary to access correct and detailed information which can be available through aerial images of remote sensing. The use of vertical aerial photography through Remote Sensing has become more common in ground collection, management and exploration, mainly because it substitutes, with lots f advantage, for cartographic bases, besides offering detailed characteristics, eliminating access difficulties in inaccessible areas, as well as facilitating a tridimensional view once it increases map efficiency and accuracy by combining field and laboratory work with photography interpretation. This work, using panchromatic aerial photography in nominal scale 1:25000 (1962), 1:45000 (1977) , and approximate nominal scale of 1:30.000, proceeding from aerial photogrameter developed in 2005, aimed at showing through the Geographic Information System (GIS) the possibility of developing a more complete and accurate analysis of the area values, obtained directly from photos without scale correction, and after comparing it with area values obtained from aerial photography with correct scale referred in IGC (Brazilian Cartography and Geography Institute) guidelines, resulting in an error coefficient which shows area differences through two proposed study. Considering the aerial photographies in three different years: 192, 1977 and 2005, it is possible to affirm that the 2005’s images presented lower values of area difference... (Complete abstract click electronic access below)