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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.
31

Modeling Building Energy Use and HVAC Efficiency Improvements in Extreme Hot and Humid Regions

Bible, Mitchell 2011 August 1900 (has links)
An energy analysis was performed on the Texas A & M University at Qatar building in Doha, Qatar. The building and its HVAC systems were modeled using EnergyPlus. Building chilled water and electrical data were collected to validate the computer simulation. The simulated monthly electricity consumption was within plus/minus 5 percent of the metered building data. Ninety-five percent of simulated hourly electricity data in a day were within plus/minus 10 percent of metered data. Monthly chilled water demand was within plus/minus 18 percent of measurements, and simulated monthly demand was correlated to metered monthly values with an R-squared correlation coefficient of 0.95. Once the simulation was verified with the metered data, an optimization of the building's HVAC systems was performed. Better utilizing the building's variable speed fans at part loads showed potential annual electricity savings of 16 percent over the base case, with another 22 percent savings in chilled water energy. After converting chilled water savings to equivalent chiller electricity savings, the potential utility cost savings over the base case were found to be $90,000/yr at local utility rates. Reducing outdoor air intake to ASHRAE indoor air quality minimums yielded an additional 17 percent in potential chilled water savings and brought total monetary savings over the base case to $110,000/yr. Using a dedicated outside air system to precisely control individual zone ventilation showed potential for an additional 12 percent chilled water savings and $14,000 in yearly utility savings, while also eliminating cases of under-ventilation. A hypothetical retrofit of fan powered terminal units (FPTU's) resulted in energy savings only at very low minimum flow rates, below ventilation standards. Savings were never more than 20 percent over the no-fan case. Series FPTU's showed no savings at any flow setting and negligible difference was found between ECM and SCR motor control. Finally, the dependence on climate of each improvement was studied. Simulations were run in the relatively milder climates of Houston and Phoenix and compared to those found for Doha. It was found that variable speed fan operation is a more cost effective option for milder climates, while outside air control is more cost effective in extreme hot and humid climates such as Doha. Future study is needed to make the FPTU model valid for different climates and flow ranges.
32

A chemostratigraphic investigation of the late Ordovician greenhouse to icehouse transition oceanographic, climatic, and tectonic implications /

Young, Seth Allen, January 2008 (has links)
Thesis (Ph. D.)--Ohio State University, 2008.
33

Non-anthropogenic sources of carbon dioxide in the Glowworm Cave, Waitomo

Miedema, Natalie Margaret. January 2009 (has links)
Thesis (M.Sc. Earth and Ocean Sciences and Chemistry)--University of Waikato, 2009. / Title from PDF cover (viewed October 2, 2009). Includes bibliographical references (p. 161-170)
34

[en] DEFINITION OF BRAZILIAN RADIO-CLIMATES AIMING THE APPLICATION TO TROPOSCATTERING / [pt] DEFINIÇÃO DE REGIÕES RÁDIO CLIMÁTICAS DO BRASIL COM APLICAÇÃO A TROPODIFUSÃO

IVONICE RAYMUNDA LOPES DA SILVA 01 February 2008 (has links)
[pt] A finalidade deste trabalho é a definição de rádioclimas brasileiros. Inicialmente é feita a apresentação dos parâmetros meteorológicos relacionados com o campo de tropodifusão fazendo-se em seguida um tratamento para verificação da coerência existente entre a teoria da difusão troposférica e métodos empíricos de previsão da atenuação. Partindo de dados de radiossondagem faz-se um estudo da atenuação esperada na região da Vilhena (RO), onde se dispões de dados de duas sondagens, nos piores meses para propagação. É feita então uma análise comparativa entre a atenuação prevista em oito cidades brasileiras e a atenuação medida, pelo Centre National d`Etude dês Télécommunication (CNET), nas regiões de clima padronizado. Chega-se assim a definição de seis tipos de rádio clima existentes no Brasil, estabelecendo-se a diferença esperada, em dB, entre a atenuação nesses rádio climas e nos rádio clima padronizados. / [en] This work was aimed to define brazilian radio-climates. We were therefore led to iniciate it by presenting the meteorological parameters related to troposcattering. This introduction is followed by a development concerned with the stablishment of a comparison between troposcatter theory and some empirical approaches. Departing from available meteorological data we have carried out a study on the expected attenuation in a region near Vilhena (RO), where the data from two sonde tests during the worst propagation months were available. At Last, we have made a comparison between the predicted Attenuation on eight brazilian cities and those measure by the Centre National d`Études des Télécommunication (CNET). We were Led to the choice of six difference radio-climates in Brazil by setting the expected difference between the attenuation these radio-climates and the one in standard radioclimate.
35

An Integrated Model Of Work Climate

Kuenzi, Maribeth 01 January 2008 (has links)
Management scholars have become increasingly interested in the role of organizational context. As part of this trend, research on work climates has thrived. This contemporary climate research differs from traditional approaches by concentrating on facet-specific climate types like service or innovation, rather than general, global conceptualizations of climate. Consequently, the climate literature has become fragmented and disorderly. I seek to remedy this in my dissertation. Specifically, I propose and test an integrated model of work climate that examines both molar and facet-specific climates. Chapter 1 is a review of the organizational work climate literature. This review seeks to review, reorganize, and reintegrate the climate literature. In addition, this review brought to light an issue that hinders the integration of the climate literatures: the literature does not contain a quality instrument for assessing the general characteristics of the molar work climate of an organization. In Chapter 2, I develop a theoretically-driven measure of work climate by drawing on the competing values framework (Quinn & Rohrbaugh, 1983). Preliminary results from three studies suggest that the proposed four-component model of molar work climate appears to be viable. The results indicate the instrument has internal reliability. Further, the results demonstrate discriminant, convergent, and criterion-related validity. In Chapter 3, I propose and test an integrated model of work climate by drawing on bandwidth-fidelity theory (Cronbach & Gleser, 1957). I predict that facet-specific climates will be more strongly related to specific outcomes and molar climates will be more strongly related to global outcomes. Further, I suggest weaker, indirect relationships between molar climate and specific outcomes and between facet-specific climates and global outcomes. The results indicate support for my predictions.
36

Finding Intersection Between School and Community

Sugati, Alsaleh 01 November 2018 (has links)
This thesis seeks to create an architectural response for learning spaces that gathers community. A school and community center are explored through the interaction at public and private zones, and day and night operation. The thesis develops a propositional response to the dualities through material, light, and scale. A particular focus within the study of light is the effort to minimize solar gains while improving daylight and view to the outside that is challenging in hot climates, such as in Jeddah, Saudi Arabia. / Master of Architecture / This thesis seeks to create an architectural response for learning spaces that gathers community. A school and community center are explored through the interaction at public and private zones, and day and night operation. The thesis develops a propositional response to the dualities through material, light, and scale. A particular focus within the study of light is the effort to minimize solar gains while improving daylight and view to the outside that is challenging in hot climates, such as in Jeddah, Saudi Arabia.
37

The role of high-resolution dataset on developing of coastal wind-driven waves model in low energy system

Baghbani, Ramin 10 May 2024 (has links) (PDF)
The spatial variation of wave climate plays a crucial role in erosion, sediment transport, and the design of management actions in coastal areas. Low energy wave systems occur frequently and over a wide range of geographical areas. There is a lack of studies assessing wave model performance in low-energy environments at a regional scale. Therefore, this research aims to model a low energy wave system using a high-resolution dataset. The specific objectives of this study involves 1) using cluster analysis and extensive field measurements to understand the spatial behavior of ocean waves, 2) develop a physics based model of wind-driven waves using high-resolution measurements, and 3) compare machine learning and physics-based models in simulating wave climates. The findings of this study indicate that clustering can effectively assess the spatial variation of the wave climate in a low energy system, with depth identified as the most important influencing factor. Additionally, the physics-based model showed varying performance across different locations within the study area, accurately simulating wave climates in some locations but not in others. Finally, the machine learning model demonstrated overall acceptable performance and accuracy in simulating wave climates and revealed better agreement with observed data in estimating central tendency compared to the physics-based model. The physics-based model performed more favorably for dispersion metrics. These findings contribute to our understanding of coastal dynamics. By providing insights into the spatial behavior of wave climates in low energy systems and comparing the performance of physics-based model and machine learning model, this research contributes to the development of effective coastal management strategies and enhances our understanding of coastal processes.
38

Conditioned atria in the built environment - A possible solution for unsustainable urbanization and climate change in Nordic climates?

Cupello de Vasconcellos, Lucas January 2020 (has links)
The aim of the research is to explore the differences in final energy consumption and environmental impact of the construction materials related to the atrium alternative and a business-as-usual and evaluate how to improve thermal properties of old buildings that require renovations to fit thermal efficiency standards and comfort in operational conditions while reducing the overall impact of the projects. Results show that for the low-rise atrium most of the parameters related to the final energy demands and environmental impacts of the atrium construction materials are proportional and linear to the increase of the glazing area size. When compared to simply renovating old structures, the atrium alternative can promote a decrease in thermal losses by transmission and increase in incident solar radiation through the glazed area depending on the atrium dimensions and glazing area size. And although cooling, heating, electrical and ventilation demands are raised for the overall demand of the building the construction of an atrium bears less environmental impact than renovating old structures damaged by weather. / <p>2021-04-08</p>
39

Customer-to-customer roles and impacts in service encounters

Lee, Linda January 2016 (has links)
This thesis investigates customer-to-customer roles and impacts in the context of service encounters. This topic is studied from two angles: customer interactions during group service encounters and customer perceptions post service encounters. The first angle is a focus on group service encounters that addresses the lack of research on customer-to-customer interactions that occur in customer-to-customer interaction-intensive contexts. These are contexts where the interactions between customers are not peripheral to the service, where there can be an expectation to interact with the other customers, and are common in tourism and hospitality, recreation, and education. The second angle is a focus on service outcomes after the service encounter, including satisfaction, intention to recommend, and online word-of-mouth. Paper 1 explores how firms view and manage customer-to-customer interactions during group service encounters. It finds that the differences in attitude and conduct of firms create four possible stances toward customer-to-customer interaction. Paper 2 delves deeper into how customer-to-customer interactions impact the design and delivery of group service encounters, develops a typology of customer cohort climates (CCCs), and identifies how each CCC can be created through four elements of group service encounters. Paper 3  investigates how positive and negative customer-to-customer interactions impact service outcomes and finds that customer-to-customer interaction is a dissatisfier. Paper 4 examines how customers produce online hotel reviews and finds that content analysis of online reviews yields similar findings to more traditional quantitative research methods. This thesis advances research on the impact of customers on each other and provides evidence that other customers can and should be managed to achieve desired service outcomes. It further proposes how these interactions can be managed to further enhance service firm offerings. / <p>QC 20160516</p>
40

The Relations Between Perceived Parent, Coach, and Peer Created Motivational Climates, Goal Orientations, and Mental Toughness in High School Varsity Athletes

Beck, Nicholas M. 08 1900 (has links)
Determining the factors that contribute to mental toughness development in athletes has become a focus for researchers as coaches, athletes, and others extol its influence on performance success. In this study we examined a model of mental toughness development based on achievement goal theory, assessing the relations between motivational climates, goal orientations, and mental toughness. Five hundred ninety-nine varsity athletes, representing 13 different sports from six different high schools in a southwestern United States school district, participated in the study. Athletes completed self-report measures assessing parent, peer, and coach motivational climates, goal orientations, and their mental toughness. Initially, I examined the measurement model and found it fit the data well both in the exploratory (SRMR = .06; CFI = .94) and confirmatory (SRMR = .06; CFI = .95) samples. Second, the structural model was examined and found to fit the data well in both the exploratory (SRMR = .08; CFI = .93) and confirmatory samples (SRMR = .07, CFI = .95). Parent task-involving climate, (β = .55; p < .05) and coach task-involving climate (β = .32; p < .05), but not peer task-involving climate (β = .05), were associated with task goal orientation (R2 = .57). Ego goal orientation (R2 = .32) was explained by peer ego-involving climate (β = .15; p < .05), parent ego-involving climate (β = .39; p < .05), and coach ego-involving climate (β = .16; p < .05). Finally, only task goal orientation (β = .75; p < .05) was related to the athletes’ mental toughness (R2 = .56); the ego goal orientation pathway was not significant (β = .04). These results speak to the potential positive influence of parents and coaches on athletes’ mental toughness through their endorsement of task-involving messages and pursuits leading to the development of a task goal orientation.

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