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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.
71

Design of a Surface Albedo Modification Payload for Near Earth Asteroid (NEA) Mitigation

Ge, Shen 2011 August 1900 (has links)
The development of the Surface Albedo Treatment System (SATS) onboard a spacecraft mission to the near earth asteroid (NEA) Apophis in 2012 is an innovative concept of deflecting NEAs from possible impact with the Earth through altering the Yarkovsky effect, a non-secular force in the solar system due to uneven surface thermal emission most profoundly affecting small rotating bodies subjected to sunlight. Though this force is small, its magnitude can be dramatic if extended over a period of time and if it uses the close approach of an asteroid near Earth to magnify the perturbation. The payload dispenses colored powder called albedo changing particles (ACPs) onto the surface changing its albedo and indirectly the surface temperature which changes the Yarkovsky effect. This study gives an in-depth description of both computational and experimental parts of the design of this system with primary focus on initial ground test setup. The initial experiments proposed to design the SATS is outlined in detail and justified by the mission criterion of interest as well as modeling the actual dispersal on the surface.
72

Radiative forcing and forest climate policy /

Thompson, Matthew P. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 70-74). Also available on the World Wide Web.
73

Methods of albedo determination from Explorer VII satellite radiation data

Takasugi, Shoji. January 1962 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 21).
74

Avaliação do nível de degradação das terras (desertificação) no alto curso da bacia hidrográfica do rio Paraíba.

ALVES, Telma Lúcia Bezerra. 14 June 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-06-14T11:32:02Z No. of bitstreams: 1 TELMA LÚCIA BEZERRA ALVES - TESE (PPGRN) 2016.pdf: 11238465 bytes, checksum: 7f1bc917d37a959d86daf700437c86cd (MD5) / Made available in DSpace on 2018-06-14T11:32:02Z (GMT). No. of bitstreams: 1 TELMA LÚCIA BEZERRA ALVES - TESE (PPGRN) 2016.pdf: 11238465 bytes, checksum: 7f1bc917d37a959d86daf700437c86cd (MD5) Previous issue date: 2016-02-25 / CNPq / A desertificação é um problema ambiental que atinge várias regiões no mundo, sendo definida como a degradação das terras nas zonas áridas, semiáridas e subúmidas resultante de vários fatores, incluindo variações climáticas e atividades humanas. O objetivo desse estudo foi avaliar o nível de degradação das terras (desertificação) no alto curso da bacia hidrográfica do Rio Paraíba, através da dinâmica temporal e espacial de aspectos climáticos, biofísicos e socioeconômicos. O alto curso da bacia hidrográfica engloba total ou parcialmente, a área de 18 municípios, distribuídos entre as microrregiões do Cariri Ocidental e Oriental do estado da Paraíba. Foram utilizados dados climáticos do período de 1950 a 2013 para as variáveis: precipitação pluvial e índice de aridez (Ia), dados de sensores orbitais - Moderate Resolution Imaging Spectro radiometer (MODIS), período de 2000 a 2013, visando à obtenção do albedo da superfície e do índice de vegetação ajustado ao solo (IVAS) e dados censitários (demográficos e agropecuários) para quantificação do índice socioeconômico e do nível de degradação na região. O teste de Mann-Kendall (MK) foi utilizado para identificação da tendência temporal das variáveis, ao nível de significância de α = 0,05, o método de Sen para quantificação da tendência e a krigagem para análise da dinâmica espacial das variáveis. Os principais resultados evidenciam que há uma tendência crescente da precipitação pluvial e decréscimo da aridez no alto curso da bacia como um todo, durante o período estudado. Pode-se inferir que estas condições não contribuem para desencadear o processo de degradação das terras (desertificação), sugerindo que as causas desse problema ambiental não são climáticas. A precipitação média anual aumenta na direção nordeste-noroeste da bacia, com mínimo (320 mm) em Cabaceiras e máximo (680 mm) nas localidades de Ouro Velho e Prata; o albedo da superfície e o índice de vegetação têm seus valores influenciados pela sazonalidade climática da região. A precipitação pluvial é o elemento que condiciona o aumento do índice de vegetação e diminuição do albedo da superfície, considerando-se que estas duas variáveis têm comportamento inverso. A região central do alto curso da bacia hidrográfica (municípios de Congo, Camalaú e Caraúbas) apresentou baixo índice de vegetação e elevado albedo da superfície, caracterizando possivelmente um processo de degradação das terras. Ao longo do período analisado (2000-2013), estas variáveis apresentaram tendência decrescente, mas não significativa, evidenciando um aumento pouco significativo da degradação das terras. Em relação ao índice socioeconômico geral de cada município – Isem observa-se que sete apresentaram “Moderada” degradação, dez “Baixa” degradação e apenas o município de Boqueirão apresentou situação de “Acentuada” degradação das terras. Os valores médios do Isem por município revelam que está havendo degradação das terras em todo o alto curso da bacia, porém em níveis Moderados e Baixos, sendo a região noroeste a área com maior pressão antrópica. Há uma tendência de aumento do índice socioeconômico - Iseb no alto curso da bacia hidrográfica com valor médio que indica uma situação de degradação “Moderada” das terras. Esse aumento é resultante do crescimento econômico, de programas sociais implantados e das melhorias nas condições de vida da população ao longo dos anos. / Desertification is an environmental problem that affects several regions in the world, defined as the land degradation of arid, semi-arid and sub-humid areas resulting from various factors, including climatic variations and human activities. The aim of this study was to evaluate the level of land degradation (desertification) in the upper course of the watershed of Paraíba River, through the temporal and spatial dynamics of climatic, biophysical and socio-economic aspects. The upper reaches of the watershed encompasses all or part of the area of 18 municipalities, distributed among the micro-regions of Western and Eastern Cariri state of Paraiba. Period of climatic data were used in 1950 the 2013 for the variables: rainfall and aridity index (Ia), orbital data from sensors - MODIS (Moderate Resolution Imaging Spectro radiometer), from 2000 to 2013, to obtain the surface albedo and Vegetation Index adjusted to the ground (SA VI) and census data (population and agricultural) to quantify the socio economic index and the level of degradation in the region. The Mann-Kendall test (MK) was used to identify the time trend variable, the level of significance o f α = 0.05, the Sen method to quantify the trend and Kriging for analyzing spatial dynamics of the variables. The main results show that there is an increasing trend of rainfall and decrease dryness on the upper course of the watershed as a whole, during the period studied. You can infer that these conditions do not contribute to trigger land degradation process (desertification), suggesting that the causes of this environmental problem is not climate. The average annual precipitation increases in the north-northwest direction of the watershed, with minimum (320 mm) in Cabaceiras and maximum (680 mm) in Ouro Velho and Prata localities; the surface albedo and vegetation index have their values influenced by the seasonality of the region. Rainfall is the element that determines the increase in vegetation index and decrease in surface albedo, considering that these two variables have opposite behavior. The central region of the upper course of the watershed (municipalities of Congo, Camalaú and Caraúbas) showe d a low rate of vegetation and high albedo surface, possibly featuring a land degradation process. Throughout the period analyzed (2000-2013), these variables showed a downward trend, but not significant, showing a slight increase of land degradation. Rega rding the general socioeconomic index of each municipality – Isem it is observed that seven had "moderate" degradation ten "Low" degradation and only the municipality of Boqueirão presented situation of "Severe" land degradation. The municipality by Isem average values reveal what's going on land degradation across the upper course of the watershed, but in Moderate and Low levels, and northwest region of the area with increased human pressure. There is a tendency to increase the socioeconomic index - Iseb in the upper course of the watershed with an average value indicating the degradation of situation "moderate" land. This increase is the result of economic growth, implemented social programs and improvements in the living conditions of the population over the years.
75

Pavement Surfaces Impact on Local Temperature and Building Cooling Energy Consumption

January 2015 (has links)
abstract: Pavement surface temperature is calculated using a fundamental energy balance model developed previously. It can be studied using a one-dimensional mathematical model. The input to the model is changed, to study the effect of different properties of pavement on its diurnal surface temperatures. It is observed that the pavement surface temperature has a microclimatic effect on the air temperature above it. A major increase in local air temperature is caused by heating of solid surfaces in that locality. A case study was done and correlations have been established to calculate the air temperature above a paved surface. Validation with in-situ pavement surface and air temperatures were made. Experimental measurement for the city of Phoenix shows the difference between the ambient air temperature of the city and the microclimatic air temperature above the pavement is approximately 10 degrees Fahrenheit. One mitigation strategy that has been explored is increasing the albedo of the paved surface. Although it will reduce the pavement surface temperature, leading to a reduction in air temperature close to the surface, the increased pavement albedo will also result in greater reflected solar radiation directed towards the building, thus increasing the building solar load. The first effect will imply a reduction in the building energy consumption, while the second effect will imply an increase in the building energy consumption. Simulation is done using the EnergyPlus tool, to find the microclimatic effect of pavement on the building energy performance. The results indicate the cooling energy savings of an office building for different types of pavements can be variable as much as 30%. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2015
76

Estimativa do saldo de radiação na região semiárida da Paraíba por meio de sensoriamento remoto orbital.

COSTA, Marcia Vanessa Gomes. 12 July 2018 (has links)
Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-07-12T18:49:35Z No. of bitstreams: 1 MARCIA VANESSA GOMES COSTA – DISSERTAÇÃO (PPGMET) 2015.pdf: 4478888 bytes, checksum: 1438314e0714853727e50726536e9cb7 (MD5) / Made available in DSpace on 2018-07-12T18:49:35Z (GMT). No. of bitstreams: 1 MARCIA VANESSA GOMES COSTA – DISSERTAÇÃO (PPGMET) 2015.pdf: 4478888 bytes, checksum: 1438314e0714853727e50726536e9cb7 (MD5) Previous issue date: 2015-08-27 / Capes / A energia total que incide sobre a superfície da Terra, afeta diretamente o balanço de radiação à superfície de forma diferenciada, a depender de aspectos biogeofísicos. A obtenção dos fluxos energéticos torna possível o estudo da dinâmica temporal de uma região específica, porém nem sempre é possível obter tais dados, devido ao número limitado de estações micrometeorológicas existentes e/ou disponíveis. Para tanto, torna-se possível a estimativa desses fluxos, como também de índices vegetativos através da utilização de imagens orbitais. O objetivo do presente trabalho é comprovar a eficácia de produtos MODIS/Terra para a estimativa do saldo de radiação para a região semiárida da Paraíba, que é uma região onde predomina o bioma Caatinga, sem a utilização de dados auxiliares de superfície. Foram utilizadas imagens referentes aos dias de ordem do ano: 25, 33, 57, 65, 81, 105, 137, 169, 193, 209, 217, 233, 249, 281, 289, 313, 329 e 361, do ano de 2013, que recobrem o Estado da Paraíba. A metodologia utilizada foi baseada em equações propostas por Bisht e Bras (2011). A validação dos resultados foi realizada com dados de duas torres micrometeorológicas experimentais, ambas estão localizadas em área de caatinga preservada e degradada, situadas no município de Campina Grande, na Paraíba. Para chegar ao resultado do saldo de radiação instantâneo, foram utilizados albedos computados de duas formas: utilizando o MCD43-A3 e o MOD09-A1. Os valores de albedo foram maiores na área degradada. Embora as estimativas tenham sofrido superestimação e subestimação, foi possível comprovar a eficácia do produto MODIS de albedo pronto (MCD43-A3) para a estimativa do saldo de radiação, com o EMP e o EMA de 16,48% e de 79,95 W/m², respectivamente; em contrapartida, o saldo obtido com o MOD09-A1 foi mais satisfatório para a área preservada, com EMP de 16,91% e EMA de 94,35 W/m² para a área degradada. O NDVI apresentou uma correlação negativa com o saldo de radiação. / The total energy falling on the surface, directly affects the radiation balance at the surface in different ways, depending on biogeophysical aspects. Obtaining of energy flows makes it possible to study the temporal dynamics of a specific region, but it is not always possible to obtain such data, due to the limited number of micrometeorological stations and / or available. Therefore, it becomes possible to estimate these flows, as well as vegetation indices using satellite images. The objective of this study is to prove the effectiveness of product MODIS / Terra to estimate the net radiation for the semi-arid region of Paraiba, which is a region dominated the Caatinga biome, without the use of auxiliary surface data. Images were used referring to days order of year 25, 33, 57, 65, 81, 105, 137, 169, 193, 209, 217, 233, 249, 281, 289, 313, 329 and 361, the year 2013 that cover the state of Paraíba. The methodology used was based on equations proposed by Bisht and Bras (2011). The validation of the results was performed with two micrometeorological towers experimental data, both are located in preserved and degraded area, located in the city of Campina Grande, Paraiba. To get to the result of the instantaneous net radiation, computed albedos were used in two ways: using the MCD43-A3 and the MOD09-A1. The albedo values were higher in degraded areas. Although estimates have been overestimation and underestimation, it was possible to prove the effectiveness of MODIS Product ready albedo, MCD43-A3, with EMP 16.48% for the radiation balance and the EMA was 79.95 W / m²; on the other hand, the balance obtained with the MOD09-A1 was more suitable for the preserved area with EMP 16.91% and EMA of 94.35 W / m² for the degraded area. The NDVI showed a negative correlation with the radiation balance.
77

O Metodo das ordenadas discretas na solucao da equacao de transporte em geometria plana com dependencia azimutal

CHALHOUB, EZZAT S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:42:57Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:16Z (GMT). No. of bitstreams: 1 06145.pdf: 4965019 bytes, checksum: afa11bbe0d27b123a27cffcd90fa9286 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
78

Análise espacial da temperatura e albedo de superfície em bacias hidrográficas / Spatial analysis of surface temperature and albedo in watersheds

Padovanni, Naia Godoy [UNESP] 01 September 2017 (has links)
Submitted by NAIA GODOY PADOVANI null (naiagp@gmail.com) on 2017-10-18T16:49:11Z No. of bitstreams: 1 NaiaGPadovanni_final.pdf: 4817773 bytes, checksum: 67b5a1858a5ffcf50056a856a74bcbce (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-10-23T17:42:38Z (GMT) No. of bitstreams: 1 padovanni_ng_me_soro.pdf: 4817773 bytes, checksum: 67b5a1858a5ffcf50056a856a74bcbce (MD5) / Made available in DSpace on 2017-10-23T17:42:38Z (GMT). No. of bitstreams: 1 padovanni_ng_me_soro.pdf: 4817773 bytes, checksum: 67b5a1858a5ffcf50056a856a74bcbce (MD5) Previous issue date: 2017-09-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O estudo dos fenômenos atmosféricos requer a compreensão de complexas relações e interações dos sistemas naturais e/ou antrópicos. As alterações da superfície terrestre alteram os processos de troca de energia entre a superfície e atmosfera em diferentes escalas, atuando na variação de temperatura da superfície e do ar, na intensidade dos fluxos de energia disponível na superfície e nas variações da energia armazenada na vegetação. A utilização de técnicas de sensoriamento remoto na compreensão dessas relações, a partir de uma abordagem geossistêmica, auxilia otimizando a obtenção de dados, no refinamento e acurácia destes e na análise sistêmica, tornando-se uma ferramenta importante para o entendimento dos processos ecológicos e antrópicos que agem nos sistemas terrestres. Neste contexto, este trabalho teve como objetivo a análise do comportamento espacial da Temperatura de Superfície (Ts) e albedo na Bacia Hidrográfica do Rio Una, Ibiúna – SP, a partir de imagens do sensor MODIS dos satélites TERRA e Aqua para os meses de Janeiro e Agostos dos anos de 2004, 2008, 2012 e 2015, considerando as modificações no uso do solo e ocupação da terra e as sazonalidades climáticas. A região de estudo vem sofrendo grandes mudanças no uso e cobertura da terra em função do crescimento urbano e das áreas de cultivo temporário e reflorestamento. Por fim, gerou-se um mapa da cobertura da terra para o ano de 2013, e a partir deste, realizou-se a análise do comportamento da Temperatura de superfície e do albedo. Os resultados obtidos foram comparados também com os dados de temperatura do ar e dados pluviométricos. / Atmospheric phenomena studies requires understanding about the complex relationships and interactions of natural and anthropic systems. Earth surface's changes alter the energy exchange processes between surface and atmosphere, at different scales, acting in : temperature variation of surface and air, the intensity of the energy streams available on the surface and the variations on energy stored in the vegetation. Remote sensing techniques utilization for the understanding of these relationships, in a geosystems approach, helps to optimize data acquisition, refinement and accuracy of these and systemic analysis, making it an important tool for the ecological and anthropic processes understanding, that act in terrestrial systems. In this context, the research's objective was the spatial behavior analysis of surface temperature (Ts) and albedo over the watershed area of the river Una (Ibiúna-SP), utilizing MODIS sensor images, from TERRA and Aqua satellites, captured in the months of January and August of 2004, 2008, 2012 and 2015, considering the changes in land use, land occupation and climatic seasonality. The study region has suffered major changes in land use and coverage on the basis of urban growth, cultivation areas and reforestation. So, a 2013 coverage map was generated, and from this, the behavior analysis of surface temperature and albedo was made. The results obtained were compared with the data of air temperature and rainfall data.
79

Pavement Temperature Effects on Overall Urban Heat Island

January 2013 (has links)
abstract: In recent years, an increase of environmental temperature in urban areas has raised many concerns. These areas are subjected to higher temperature compared to the rural surrounding areas. Modification of land surface and the use of materials such as concrete and/or asphalt are the main factors influencing the surface energy balance and therefore the environmental temperature in the urban areas. Engineered materials have relatively higher solar energy absorption and tend to trap a relatively higher incoming solar radiation. They also possess a higher heat storage capacity that allows them to retain heat during the day and then slowly release it back into the atmosphere as the sun goes down. This phenomenon is known as the Urban Heat Island (UHI) effect and causes an increase in the urban air temperature. Many researchers believe that albedo is the key pavement affecting the urban heat island. However, this research has shown that the problem is more complex and that solar reflectivity may not be the only important factor to evaluate the ability of a pavement to mitigate UHI. The main objective of this study was to analyze and research the influence of pavement materials on the near surface air temperature. In order to accomplish this effort, test sections consisting of Hot Mix Asphalt (HMA), Porous Hot Mix asphalt (PHMA), Portland Cement Concrete (PCC), Pervious Portland Cement Concrete (PPCC), artificial turf, and landscape gravels were constructed in the Phoenix, Arizona area. Air temperature, albedo, wind speed, solar radiation, and wind direction were recorded, analyzed and compared above each pavement material type. The results showed that there was no significant difference in the air temperature at 3-feet and above, regardless of the type of the pavement. Near surface pavement temperatures were also measured and modeled. The results indicated that for the UHI analysis, it is important to consider the interaction between pavement structure, material properties, and environmental factors. Overall, this study demonstrated the complexity of evaluating pavement structures for UHI mitigation; it provided great insight on the effects of material types and properties on surface temperatures and near surface air temperature. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2013
80

O Metodo das ordenadas discretas na solucao da equacao de transporte em geometria plana com dependencia azimutal

CHALHOUB, EZZAT S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:42:57Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:16Z (GMT). No. of bitstreams: 1 06145.pdf: 4965019 bytes, checksum: afa11bbe0d27b123a27cffcd90fa9286 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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