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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

Thermal gradients and water transfer in unsaturated soil.

Tromble, John Merrill,1932- January 1973 (has links)
An investigation into the flux of soil water under the influence of a thermal gradient was conducted in closed soil systems in the laboratory. A thermal gradient was imposed across the sandy loam soil columns and measured continuously for the duration of the experiment. The movement of soil water was monitored periodically using a gamna ray attenuation device until the columns reached an apparent steady state condition with no net flow. Imposition of boundary conditions enabled delineation and evaluation of the system parameters. Values of net water flux in soil columns were analyzed using the Taylor-Cary irreversible thermodynamic and the Philip-de Vries theory of water movement. Application of the Taylor-Cary equation to describe the flow reveals that for initial time periods the flow is slightly overestimated, however, this small difference may be within the realm of experimental error. The flow predicted by the Taylor-Cary equation for the succeeding time periods greatly exceeded the measured flow rates. The Philip-de Vries theory of soil-water movement predicted greater net water movement than was observed in soil columns with a temperature gradient of 2.67 ° C/cm and with an average soil water content of 10.5 to 11.5 cm³/cm³. The following conclusions were reached after analyzing the data for the sandy loam soil material. Water content and temperature influence the diffusion transfer coefficient, β*, in a closed soil system. Thus the transfer coefficient is not an independent entity. Hysteresis is present in the wetter part of the system, although the magnitude of hysteresis involved is unknown. The β* coefficient can be evaluated only in regions where hysteresis is not present. The transfer of soil water was greater in a leached soil with no air gap than in an unleached soil with no air gap. There was supporting evidence that liquid water continuity did not exist throughout the column since there was no appreciable solute transport. The observed change in soil water content distribution at 18.0 cm³/cm³ to the imposed temperature gradient was not significant for the sandy loam soil material. The observed soil water flux increased in response to the imposed temperature gradient as soil water content decreased from 18.0 to 10.5 cm³/cm³. No analytical procedure is presently available that will describe thermally induced flow under all conditions. The approach of Philip and de Vries requires that the physical properties of the soil must be known accurately so that correct estimates can be made of the individual diffusivities. This approach has been found to predict the flow with some success on relatively dry soils, however, it possibly would be in error when estimating thermally induced flow in regions where liquid continuity exists and up through to a saturated system. The Taylor and Cary equation may be adequate for describing water flow to predict trends or obtain comparative values, however, much additional work needs to be done before it will adequately describe the flow for transient conditions or steady state conditions where nonuniform water content distributions are present.
2

The effects of cyclic freeze-thaw on the properties of high water content clays /

Tucker, Alison. January 1985 (has links)
No description available.
3

Effects of drying methods, extent, and inorganic cementing constituents on the structural properties of typic Hydrandepts of Hawaii's forestland

Lim, Howard Sookil January 1979 (has links)
Photocopy of typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1979. / Bibliography: leaves 184-198. / Microfiche. / xvi, 224 leaves ill. 29 cm
4

The effects of cyclic freeze-thaw on the properties of high water content clays /

Tucker, Alison. January 1985 (has links)
No description available.
5

Geoprocessamento na identificação de ilhas de calor e influência do uso e ocupação do solo na temperatura aparente da superfície no município de Botucatu/SP

Mashiki, Mônica Yuri [UNESP] 14 December 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-12-14Bitstream added on 2014-06-13T19:31:28Z : No. of bitstreams: 1 mashiki_my_me_botfca.pdf: 1336062 bytes, checksum: 77b248004092a36d5eb04226bad1f78e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / A radiação eletromagnética recebida pelos materiais de diferentes composições presentes na superfície terrestre emite ondas de radiação proporcionais a sua temperatura. Segundo a lei de Planck quanto maior a temperatura de um dado corpo, maior radiação eletromagnética será emitida pelo corpo. Os satélites através dos seus sensores captam os diferentes comprimentos de onda do espectro eletromagnético gerando imagens de grande utilidade no sensoriamento remoto para estudos de diversas áreas do conhecimento. Este trabalho teve como objetivo analisar a influência dos diferentes usos e ocupação do solo na temperatura aparente da superfície no município de Botucatu/SP, através de imagens do satélite Landsat-5 captadas no dia 19/11/2010, órbita/ponto 220/076. Para o geoprocessamento das imagens utilizou-se o programa IDRISI versão ANDES. O algoritmo thermal foi utilizado para transformação dos níveis de cinza em graus Celsius. Foram utilizadas as bandas 3, 4 e 5 para composição falsa cor e visualização dos diferentes usos do solo e a banda 6, para a confecção do mapa temático da temperatura aparente da superfície. Dentre as classes verificadas, a classe de uso água apresentou a menor temperatura, 20.9ºC, devido ao seu elevado calor específico (1cal/gºC). Para classe de uso Eucalipto a temperatura encontrada foi 23.8ºC. A classe mata nativa variou sua temperatura entre 25.5 – 23.65 ºC, dentre as duas áreas distintas observadas. A classe solo exposto apresentou temperatura aparente de 33.6ºC, média próxima aos valores encontrados na classe área urbana. Para análise do meio urbano, seguiu-se a divisão em setores (Norte, Sul, Leste, Oeste e Centro) proposta pela prefeitura e em Regiões Operacionais, devido à grande heterogeneidade deste ambiente. O setor Norte apresentou a maior temperatura... / The electromagnetic radiation received by the different material composition presents on the land surface emits proportional radiation waves as its temperature. According to the Planck law how higher temperature of a given body, higher electromagnetic radiation will be emitted. Through its sensors satellites capture different length wave of the electromagnetic spectrum generating images to the study of different areas of remote sensing knowledge. This study aimed to analyze the influence of the different soil use and occupation in land surface temperature in the city of Botucatu/SP through images from the satellite Landsat 5 captured on 11/19/2010, path/row 220/076. For the images geoprocessing was used the program IDRISI ANDES version. The thermal algorithm was used to transform grey levels into Celsius degree. It was used the bands 3, 4 and 5 to the false color composition and visualization of the different soil uses. Between the classes verified the use water presents the lowest temperature, 20.9ºC, because of the high specific heat (1cal/gºC). The temperature of the class eucalyptus was 23.8ºC. The Native Forest class presents temperature between 25.5 – 23.65 ºC. Exposed soil presents 33.6ºC of land surface temperature, values closer to the urban area class. Urban environment analysis was divided into sectors (North, South, East, West and city center) and into operational regions because of your heterogeneity. The North sector presents the higher land surface temperature 32.7ºC, following by East sector with 32.1ºC and the city center 31.2ºC. The sectors with the lowest land surface temperature was West (28.6ºC) and South (29.8ºC). Remote sensing and geoprocessing are fundamental tools to the analysis of land surface temperature morphology without which it was not possible visualize this... (Complete abstract click electronic access below)
6

Geoprocessamento na identificação de ilhas de calor e influência do uso e ocupação do solo na temperatura aparente da superfície no município de Botucatu/SP /

Mashiki, Mônica Yuri, 1985- January 2012 (has links)
Orientador: Sérgio Campos / Banca: Osmar Delmanto Junior / Banca: Fernanda Leite Ribeiro / Resumo: A radiação eletromagnética recebida pelos materiais de diferentes composições presentes na superfície terrestre emite ondas de radiação proporcionais a sua temperatura. Segundo a lei de Planck quanto maior a temperatura de um dado corpo, maior radiação eletromagnética será emitida pelo corpo. Os satélites através dos seus sensores captam os diferentes comprimentos de onda do espectro eletromagnético gerando imagens de grande utilidade no sensoriamento remoto para estudos de diversas áreas do conhecimento. Este trabalho teve como objetivo analisar a influência dos diferentes usos e ocupação do solo na temperatura aparente da superfície no município de Botucatu/SP, através de imagens do satélite Landsat-5 captadas no dia 19/11/2010, órbita/ponto 220/076. Para o geoprocessamento das imagens utilizou-se o programa IDRISI versão ANDES. O algoritmo thermal foi utilizado para transformação dos níveis de cinza em graus Celsius. Foram utilizadas as bandas 3, 4 e 5 para composição falsa cor e visualização dos diferentes usos do solo e a banda 6, para a confecção do mapa temático da temperatura aparente da superfície. Dentre as classes verificadas, a classe de uso água apresentou a menor temperatura, 20.9ºC, devido ao seu elevado calor específico (1cal/gºC). Para classe de uso Eucalipto a temperatura encontrada foi 23.8ºC. A classe mata nativa variou sua temperatura entre 25.5 - 23.65 ºC, dentre as duas áreas distintas observadas. A classe solo exposto apresentou temperatura aparente de 33.6ºC, média próxima aos valores encontrados na classe área urbana. Para análise do meio urbano, seguiu-se a divisão em setores (Norte, Sul, Leste, Oeste e Centro) proposta pela prefeitura e em Regiões Operacionais, devido à grande heterogeneidade deste ambiente. O setor Norte apresentou a maior temperatura... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The electromagnetic radiation received by the different material composition presents on the land surface emits proportional radiation waves as its temperature. According to the Planck law how higher temperature of a given body, higher electromagnetic radiation will be emitted. Through its sensors satellites capture different length wave of the electromagnetic spectrum generating images to the study of different areas of remote sensing knowledge. This study aimed to analyze the influence of the different soil use and occupation in land surface temperature in the city of Botucatu/SP through images from the satellite Landsat 5 captured on 11/19/2010, path/row 220/076. For the images geoprocessing was used the program IDRISI ANDES version. The thermal algorithm was used to transform grey levels into Celsius degree. It was used the bands 3, 4 and 5 to the false color composition and visualization of the different soil uses. Between the classes verified the use water presents the lowest temperature, 20.9ºC, because of the high specific heat (1cal/gºC). The temperature of the class eucalyptus was 23.8ºC. The Native Forest class presents temperature between 25.5 - 23.65 ºC. Exposed soil presents 33.6ºC of land surface temperature, values closer to the urban area class. Urban environment analysis was divided into sectors (North, South, East, West and city center) and into operational regions because of your heterogeneity. The North sector presents the higher land surface temperature 32.7ºC, following by East sector with 32.1ºC and the city center 31.2ºC. The sectors with the lowest land surface temperature was West (28.6ºC) and South (29.8ºC). Remote sensing and geoprocessing are fundamental tools to the analysis of land surface temperature morphology without which it was not possible visualize this... (Complete abstract click electronic access below) / Mestre
7

Behaviour of alkaline sodic soils and clays as influenced by pH and particle change

Chorom, Mostafa. January 1996 (has links) (PDF)
Copies of author's previously published articles inserted. Bibliography: leaves 173-196. The objective of this thesis is to investigate the factors affecting swelling and dispersion of alkaline sodic soils containing lime and the ways to manage these soils to improve their physical condition. Studies on pure clay systems are included to understand the fundamental process involved in swelling and dispersion of pure and soil clays.
8

Behaviour of alkaline sodic soils and clays as influenced by pH and particle change / Mostafa Chorom.

Chorom, Mostafa January 1996 (has links)
Copies of author's previously published articles inserted. / Bibliography: leaves 173-196. / xviii, 197 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The objective of this thesis is to investigate the factors affecting swelling and dispersion of alkaline sodic soils containing lime and the ways to manage these soils to improve their physical condition. Studies on pure clay systems are included to understand the fundamental process involved in swelling and dispersion of pure and soil clays. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science

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