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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.
11

Late Little Ice Age glacier fluctuations in the Cascade Range of Washington and northern Oregon /

O'Neal, Michael Aaron. January 2005 (has links)
Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 99-111).
12

Modern and late Holocene climate-tree-ring growth relationships and growth patterns in Douglas-fir, coastal British Columbia, Canada

Zhang, Qibin 04 May 2018 (has links)
This thesis investigates nonlinear climate-growth relationships and spatio-temporal variations in radial growth of Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) in coastal British Columbia (BC), Canada. The technique of Artificial Neural Network (ANN) is used to model tree-ring growth response to climatic variables. Spatial variations in radial growth are examined by comparing ring-width chronologies from three sites on southeastern Vancouver Island and nine sites in Bella Coola area of central coast BC. Radial growth in late Holocene is analyzed by examining ring-width chronologies developed from subfossil Douglas-fir at the Heal Lake site on southern Vancouver Island. A two-level linear aggregate model is proposed as an improved conceptual framework for study of tree-rings and environment. This model is useful for better understanding the interactions and transformations between different environmental factors and for unambiguous interpretation of the impact of disturbance on tree growth. The ANN technique is demonstrated to be superior to the traditional linear regression approach because of its ability to capture nonlinear and complex relationships between climatic variables and tree-ring growth. The ANN model can be used to predict tree-ring growth under given climatic conditions, and to understand climate-growth relationships by scenario analysis. Comparisons of tree-ring chronologies from three sites on southeastern Vancouver Island suggest that the climate-growth responses are generally similar. In the Bella Coola area of central coast BC, principal component analysis shows that there is common growth response throughout the nine sites of different elevations. However, there is also contrasting growth responses between sites of high and low elevations. The growing season precipitation is likely a major factor controlling radial growth of Douglas-fir on macro-regional scale in coastal BC. Five floating ring-width chronologies in the past 3rd and 4th millennia are developed using 79 subfossil Douglas-fir from the Heal Lake site on southern Vancouver Island. These chronologies show slight fluctuations and strong variations at different intervals. Notable growth anomalies occurred at about 4000 years before present, suggesting intense environmental changes, e.g., frost and droughts, at a time of suspected climate transition. The results of this study will be of use to forest management and climate studies in coastal BC. / Graduate
13

Organizational Perspectives of Faculty and Administrators in a Southwest Community College District

Jackson, Zena McClellan 08 1900 (has links)
This quantitative study analyzed data from ModernThink’s Best Places to Work survey to describe if employees of different ethnic groups in a community college district held similar or different perspectives on aspects of the work place. ModernThink’s survey describes the perspectives of employees from the view of the individual, the workgroup, and the organization on the competencies of organizational: leadership, communication, respect, and alignment. The study analyzed responses from 457 faculty and administrators to describe workplace perspectives across the district, at seven campuses, and by ethnic group. The results revealed that the employee workgroup was neutral in its perceptions of both the perspectives and competencies for the district; by ModernThink’s criteria the district was not a best place or a poor place to work. Based on the overall responses, four campuses rated as a best place to work; three campuses were rated as neutral. Of the perspectives, one campus rated best in all three factors and two campuses rated best on two of three factors. Rating variations between the two ethnic groups were minimal across the district and only diverged at two of the seven campuses. Although the study did not examine campus culture or climate, the findings suggest that campus climates vary and likely influenced the survey responses.
14

Nitrogen removal from wastewater by an aerated subsurface flow constructed wetland

Redmond, Eric 01 May 2012 (has links)
The purpose of this research was to assess the ability of subsurface flow wetlands, with aeration and vegetation, to remove nitrogen in cold weather climates. Aeration was shown to enhance the wetland cell's ability to remove not only nitrogen but also CBOD, COD, and phosphorus (retention) more effectively. There was a significant difference (p< 0.05) in both total nitrogen and ammonia effluent concentrations comparing aerated to unaerated wetland cells, while no significance was found comparing planted and unplanted wetland cells. The effluent ammonia concentrations from the aerated wetland cells ranged from 2.7 to 5.7 mg N/L, while for unaerated cells effluent concentration ranged from 22 to 23 mg N/L. The effluent total nitrogen concentrations from the aerated wetland cells ranged from 9.0 to 12 mg N/L, while those from unaerated cells ranged from 23 to 24 mg N/L. The effluent concentrations showed no significant difference (p < 0.05) when comparing results of three temperature ranges. There is a correlation when comparing ammonia mass removal rates to mass loading rates. Ammonia removal in the aerated wetland cells ranged from 82 to 95%, while unaerated cells ranged from 39 to 45%. The hydraulic retention times ranged from 3.13 to 4.33 days and the tanks-in-series ranged from 1.46 to 2.84. Using this information the wetland cells were modeled using both the TIS and the PkC* models. The k values (PkC* model) of the aerated wetlands for ammonia ranged from 131 to 221 m/d, while the unaerated wetland cells had values ranging from 20.4 to 36.7 m/d. The models appear to show a good prediction of the effluent ammonia concentration for the unaerated cells but the aerated cells show the model does not effectively capture the effects of aeration.
15

Measuring Sports Class Learning Climates - the Development of the Sports Class Environment Scale

Dowdell, Trevor John, N/A January 2007 (has links)
Teaching (in this study, coaching) is a key determinant in learning any sports skill. The coach-athlete relationship is one of the most important influences on athlete's motivation and performance (Mageau & Vallerand, 2003). One of the key leadership roles the coach has in this relationship is the creation and maintenance of the sports class learning climate. The joint influence of the athlete's motivation and the environmental press (class learning climate) can determine the cognitive, affective, and performance patterns regularly displayed by athletes (Ntoumanis & Biddle, 1999). A sports class' learning climate is a set of internal characteristics that has an important role in shaping an athlete's motivational and behavioural pattern (Ames, 1992) and is a key characteristic of class effectiveness. In sports classes, motivational climate is a sub-set of the overall learning climate and is created primarily by the sport class coach. Motivational climate can be described as the participants' relatively persistent collective perceptions of the achievement goal structure of that setting. Recent studies of motivational climate in sport have provided insight into coaching behaviour and its effect on sports class motivational climate (Ntoumanis & Biddle, 1999). In spite of the potential value of class learning climate research to the field of sports class behavioural studies, no research has consolidated the fields of classroom learning climate research and sports class motivational climate studies. This study provides a model for the investigation of gymnastics sports class learning climates that involves a consolidation of the dimensions and items of the Perceived Motivational Climate in Sport Questionnaire-2 (Newton, Duda, & Yin, 2000) and the Classroom Environment Scale (Moos & Trickett, 1987). The development and validation of a new, unique learning climate scale - the Sports Class Environment Scale (SCES) - constitutes the focus of this research. The process of developing this consolidated instrument began with the production of an initial scale, and was followed by a review by a panel of experts in coaching and independent university researchers in sport and physical education. The SCES draft was then pilot tested with a small group (n = 41) of competitive gymnasts to prompt some changes to the scale. Initial field-testing of the SCES occurred with 28 male and 180 female competitive gymnasts from 6 metropolitan and 4 regional competitive gymnastics clubs in Queensland, Australia. Exploratory factor analysis provided a revised SCES with five subscales labeled Task Involvement and Improvement, Ego Involvement and Mistakes, Coach-Athlete Communication, Effort, Order and Organization, and Affiliation. Using the revised SCES subscales as dependent variables, multivariate analyses of variance were conducted to compare club type, gender, and competitive level. In this study, the low training hours and the high training hours gymnastics classes were different in their perceptions of the Ego Involvement of their class climate. Male and female gymnasts were different in their perceptions of Ego Involvement, Affiliation, and Effort, Order and Organization aspects of their class climates. This study demonstrates the potential utility of creating class learning climates high in both Task Involvement and Ego Involvement for competitive gymnastics clubs. This study breaks new ground, and may lead to novel insights into sports class learning climates. Because class learning climate is easier to manipulate than individual achievement goal dispositions (Whitehead, Andree, & Lee, 1997) and because perceptions of learning climate account for variance in learning outcomes beyond that attributable to student ability (Fraser, 1994, 1998, 2002), class learning climate is an important variable that should be better understood, described, developed, and manipulated. Effective measurement of sports class learning climates using the SCES may lead to a greater understanding of effective sports classes, and of coach and athlete behaviours in those classes, and provides a first step in monitoring sports class learning climates.
16

Evaluation and design of double-skin facades for office buildings in hot climates

Yellamraju, Vijaya 30 September 2004 (has links)
The main objectives of this research are (a) to investigate the thermal effect of double skin facades in office buildings in hot climates and (b) to propose guidelines for their efficient design based on this evaluation. The study involves the energy performance analysis of two buildings in India. A base case with the existing building skin was simulated for both the cities. The main source for the high cooling loads was found to be heat gain through windows and walls. This led to the evolution of a series of facade strategies with the goals of reducing heat gain, providing ventilation and day-lighting. The buildings were then simulated for their energy performance with the proposed double-skin strategies. Each of these strategies was varied according to the layers constituting the facade, the transparency of the facade and the orientation of the facade to which it is applied. Final comparisons of energy consumption were made between the proposed options and the base case to find the most efficient strategy and also the factors that affected this efficiency. The simulations were done using the building simulation software, Ener-Win. The double skin was simulated as per an approximate and simplistic calculation of the u-value, solar heat gain coefficient and transmissivity properties of the layers constituting the facade. The model relied on logically arrived at assumptions about the facade properties that were approximately within 10% range of measured values. Based on inferences drawn from these simulations, a set of design guidelines comprised of goals and parameters was generated for design of double-skin facades in hot climates typical to most of the Indian subcontinent. It was realized that the double-skin defined typically as a 'pair of glass skins separated by an air corridor' may not be an entirely energy efficient design strategy for hot climates. However, when used appropriately in combination with other materials, in the right orientation and with the right transparency, a double-layered facade turns out to be an energy efficient solution.
17

An analysis of maximum residential energy-efficiency in hot and humid climates

Malhotra, Mini 12 April 2006 (has links)
Energy-efficient building design involves minimizing the energy use and optimizing the performance of individual systems and components of the building. The benefits of energyefficient design, in the residential sector, are direct and tangible, provided that design strategies with a substantial combined energy and cost-saving potential are adopted. Many studies have been performed to evaluate the energy-saving potential and the costeffectiveness of various design options, and to identify conditions for optimizing the performance of building systems and components. The results of these studies, published in various resources, were analyzed discretely using different techniques, and were reported using different bases for comparison. Considering the complex interaction of, and energy flows through various building components, it is difficult to directly compare/combine the results from various studies to determine the energy-saving potential of combination of strategies, and to select an appropriate set of strategies for making design decisions. Therefore, this thesis develops a comprehensive survey and analysis of energy-efficient design strategies and their energy-saving potential, in isolation as well as in combination, using a DOE-2 simulation model of a prototype house in the hot and humid climate of Houston, Texas. Optimized strategies that included building configuration, materials/ assembly for building envelop components, and efficient mechanical and electrical systems, equipment and appliances, were applied in combination that could minimize the annual energy use. Application of these strategies is expected to allow downsizing systems and equipment and to confirm their operation at their rated performance, resulting in additional installation and operation cost savings. The study is concluded by outlining the procedures for selecting optimized set of strategies, and by developing guidelines for achieving maximum energy-efficiency in singlefamily detached houses in hot and humid climates. Thus, this study will facilitate the selection of energy-saving measures for their individual or combined application for developing energyefficient residences in hot and humid climates.
18

Evaluation and design of double-skin facades for office buildings in hot climates

Yellamraju, Vijaya 30 September 2004 (has links)
The main objectives of this research are (a) to investigate the thermal effect of double skin facades in office buildings in hot climates and (b) to propose guidelines for their efficient design based on this evaluation. The study involves the energy performance analysis of two buildings in India. A base case with the existing building skin was simulated for both the cities. The main source for the high cooling loads was found to be heat gain through windows and walls. This led to the evolution of a series of facade strategies with the goals of reducing heat gain, providing ventilation and day-lighting. The buildings were then simulated for their energy performance with the proposed double-skin strategies. Each of these strategies was varied according to the layers constituting the facade, the transparency of the facade and the orientation of the facade to which it is applied. Final comparisons of energy consumption were made between the proposed options and the base case to find the most efficient strategy and also the factors that affected this efficiency. The simulations were done using the building simulation software, Ener-Win. The double skin was simulated as per an approximate and simplistic calculation of the u-value, solar heat gain coefficient and transmissivity properties of the layers constituting the facade. The model relied on logically arrived at assumptions about the facade properties that were approximately within 10% range of measured values. Based on inferences drawn from these simulations, a set of design guidelines comprised of goals and parameters was generated for design of double-skin facades in hot climates typical to most of the Indian subcontinent. It was realized that the double-skin defined typically as a 'pair of glass skins separated by an air corridor' may not be an entirely energy efficient design strategy for hot climates. However, when used appropriately in combination with other materials, in the right orientation and with the right transparency, a double-layered facade turns out to be an energy efficient solution.
19

The weather and climate of Australia at the Last Glacial Maximum

Hope, Pandora January 2005 (has links) (PDF)
The global climate has experienced four glacial cycles in the last 420,000 years, with each cycle characterised by a prolonged period of cooling culminating in maximal glaciation followed by a brief warm period. The most recent period of maximal glaciation is termed the Last Glacial Maximum (LGM) and occurred about 21,000 years ago. We currently live in one of the warm periods. The global climate is changing, and it is becoming more important to understand the extremes of the climate system and how well our modelling capability can capture those extremes. / There has been a modelling intercomparison project established to examine how global general circulation models compare in simulating past climates, including the LGM. Analysis and comparison of these model results has been presented for many parts of the globe, but there has not been a comparison of the different model results over the Australian region. This thesis aims to fill that gap and explore the simulated LGM weather and climate of Australia and its drivers in more detail. Comparison with proxy evidence is also undertaken, and inconsistencies seen in the literature addressed. / The Australian climate at the LGM was believed to be generally cooler, drier and possibly windier from proxy evidence in the literature. In the comparison done here the mean temperature and precipitation fields from most models show cooler and drier conditions, with some seasonal variability, but there are some strong outliers. It was found that the differences were not dependent on model resolution, but that the surface parameterisations were highly important for these fields. / The shifts in the circulation were examined both in the model results and with a study of the non-linear link between the wind, surface moisture and dunes, which are a proxy for past winds. All the models simulate a southward shift in the westerlies in the Australian region. This is strongly driven byte prescribed sea-surface temperatures. Australia's current wind regime is conducive to dune building. However, the binding effect of soil moisture (or vegetation) is strong enough to limit present day movement, whereas in the drier climate at the LGM there was a capacity for sand movement. The analysis of dune orientations did not produce conclusive evidence for how the westerlies might have shifted at the LGM. / An apparent enigma in the proxy evidence at the LGM is the high lake levels in Australia’s south east, while most inland lakes were dry. Previous authors believed that the precipitation was still low, but the high lake levels were driven by lowered potential evaporation. The hydrological cycle was generally depressed in the LGM simulations, but the potential for evaporation remained high. Thus an alternative hypothesis is posed based on increased run off due to a known shift in the vegetation types and a lag in the timing of the run off due to snowmelt. / The analysis here shows that our capacity to simulate climates quite different from the present is still developing, but that model results can help explain apparent inconsistencies in the reconstruction of past climates from proxies.
20

Frost heaving and surface clast movement in turf-banked terraces, Eastern Glacier National Park, Montana /

Sawyer, Carol Frances. January 1900 (has links)
Thesis (Ph. D.)--Texas State University-San Marcos, 2007. / Vita. Appendices: leaves 178-213. Includes bibliographical references (leaves 214-234).

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