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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

Soil-moisture characteristics of Hong Kong soils in the low suction range /

Liu, Chee-chuen. January 1981 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1981.
2

Calibration of the soil moisture accounting model using the adaptive random search algorithm

Weinig, Walter Theodore, January 1991 (has links) (PDF)
Thesis (M.S. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 96-99).
3

Estimation of soil moisture in the southern united states in 2003 using multi-satellite remote sensing measurements

Soriano, Melissa. January 2008 (has links)
Thesis (M.S.)--George Mason University, 2008. / Vita: p. 65. Thesis director: John Qu. Submitted in partial fulfillment of the requirements for the degree of Master of Science in Earth System Science. Title from PDF t.p. (viewed Jan. 11, 2009). Includes bibliographical references (p. 59-64). Also issued in print.
4

Moisture conditions associated with pavements in South Africa

Haupt, Frank Johannes 26 January 2015 (has links)
A variety of geotechnical and pavement engineering problems require that one know whit the eventual moisture conditions under a covered area will be, as considerable savings may result from preventive design measures. The historical development of the theory describing soil water movement is summarized and the factors affecting the establishment of the moisture regime in pavements are discussed. & comprehensive literature survey, firstly to determine the state of the knowledge concerning pavement moisture conditions and secondly to accumulate the greater part of available moisture prediction techniques, was carried out and the salient features are highlighted. It was decided to evaluate these models' prediction accuracies when applied to local conditions and for this all available local moisture information was gathered. The most common methods available to measure soil water potential are briefly discussed and recommendations regarding routine measurements put forward. None of the models tested were found to be applicable without modifications and consequently an exhaustive statistical analysis of the local data was undertaken in order to develop more accurate empirical prediction techniques for local conditions. This analysis included multiple stepwise linear regressions, the transformation and combination of certain predictors, linear regressions for certain ranges of values, non-linear regressions and linear regressions on only selected parameters. Conclusions about general moisture trends have also been drawn. The influence of climate and compactive effort on the empirical prediction models were evaluated and recommendations put forward as to how these influences may be accounted for in design. A method is proposed for calculating a probable maximum (or minimum) moisture content for design purposes. The term "characteristic maximum (or minimum) moisture content" is defined as that moisture content above (or below) which only a certain percentage of actual moisture content values will fall. The application of this concept in pavement and geotechnical engineering is explained. Relationships between other soil engineering parameters are also given. A provisional rational method, incorporating soil suction, is also proposed for completeness1 sake. This method is intended, at least initially, to serve as a check on the empirical method, but with time it is bound to be refined to a more accurate
5

Preliminary non-destructive assessment of moisture content, hydration and dielectric properties of Portland cement concrete

Avelar Lezama, Ivan 25 April 2007 (has links)
Moisture availability is a focal point in the structural development of young concrete. Under low humidity and hot weather conditions, concrete loses moisture rapidly as it hardens, and it is very difficult, if not impossible, to minimize this loss even though proper curing procedures are used. Early losses in moisture content jumpstart premature surface self-dissecation, increase surface paste porosity, prevent concrete from achieving the mechanical properties for which it was originally designed, and facilitate the development of surface distresses such as spalling. Curing effectiveness and structural assessment of young concrete is generally done through conventional destructive or invasive testing. However, there is no fully established non-destructive testing protocol to assess moisture content and its effects on concrete properties quantitatively in an on-site, fast, and non-invasive way. The possibility and feasibility of establishing a testing protocol with such attributes is explored. Previous research on pavement bases has used dielectric measurements to relate moisture content to their structural performance. Due to the high dielectric value of water as compared to any other material used in construction, it is possible to relate high volumetric water content to high dielectric readings. In this study, compressive strength tests combined with dielectric and mass measurements are used to investigate how dielectric properties change with hydration. The results of this study suggest that it may be possible to approximate the volumetric moisture content in concrete by measuring the dielectric value of concrete as it hardens.
6

Modeling and application of soil moisture at varying spatial scales with parameter scaling

Das, Narendra Narayan 15 May 2009 (has links)
The dissertation focuses on characterization of subpixel variability within a satellite-based remotely sensed coarse-scale soil moisture footprint. The underlying heterogeneity of coarse-scale soil moisture footprint is masked by the area-integrated properties within the sensor footprint. Therefore, the soil moisture values derived from these measurements are an area average. The variability in soil moisture within the footprint is introduced by inherent spatial variability present in rainfall, and geophysical parameters (vegetation, topography, and soil). The geophysical parameters/variables typically interact in a complex fashion to make soil moisture evolution and dependent processes highly variable, and also, introduce nonlinearity across spatio-temporal scales. To study the variability and scaling characteristics of soil moisture, a quasi-distributed Soil-Vegetation-Atmosphere-Transfer (SVAT) modeling framework is developed to simulate the hydrological dynamics, i.e., the fluxes and the state variables within the satellite-based soil moisture footprint. The modeling framework is successfully tested and implemented in different hydroclimatic regions during the research. New multiscale data assimilation and Markov Chain Monte Carlo (MCMC) techniques in conjunction with the SVAT modeling framework are developed to quantify subpixel variability and assess multiscale soil moisture fields within the coarse-scale satellite footprint. Reasonable results demonstrate the potential to use these techniques to validate multiscale soil moisture data from future satellite mission e.g., Soil Moisture Active Passive (SMAP) mission of NASA. The results also highlight the physical controls of geophysical parameters on the soil moisture fields for various hydroclimatic regions. New algorithm that uses SVAT modeling framework is also proposed and its application demonstrated, to derive the stochastic soil hydraulic properties (i.e., saturated hydraulic conductivity) and surface features (i.e., surface roughness and volume scattering) related to radar remote sensing of soil moisture.
7

Preliminary non-destructive assessment of moisture content, hydration and dielectric properties of Portland cement concrete

Avelar Lezama, Ivan 25 April 2007 (has links)
Moisture availability is a focal point in the structural development of young concrete. Under low humidity and hot weather conditions, concrete loses moisture rapidly as it hardens, and it is very difficult, if not impossible, to minimize this loss even though proper curing procedures are used. Early losses in moisture content jumpstart premature surface self-dissecation, increase surface paste porosity, prevent concrete from achieving the mechanical properties for which it was originally designed, and facilitate the development of surface distresses such as spalling. Curing effectiveness and structural assessment of young concrete is generally done through conventional destructive or invasive testing. However, there is no fully established non-destructive testing protocol to assess moisture content and its effects on concrete properties quantitatively in an on-site, fast, and non-invasive way. The possibility and feasibility of establishing a testing protocol with such attributes is explored. Previous research on pavement bases has used dielectric measurements to relate moisture content to their structural performance. Due to the high dielectric value of water as compared to any other material used in construction, it is possible to relate high volumetric water content to high dielectric readings. In this study, compressive strength tests combined with dielectric and mass measurements are used to investigate how dielectric properties change with hydration. The results of this study suggest that it may be possible to approximate the volumetric moisture content in concrete by measuring the dielectric value of concrete as it hardens.
8

Measurement of the surface forces in soils

Shull, Charles Albert. January 1916 (has links)
Dissertation : Botany : Chicago : 1916. / "Bibliographie": p. 29-31.
9

Objective analysis of horizontal moisture patterns.

O’Neill, Archibald Desmond Joseph. January 1965 (has links)
Since 1946 the development of the electronic computer has simplified and speeded up the processing of data of all types. Consequently, many scientific problems have either become tractable for the first time or can now be approached in a more rigorous and less subjective manner. Specifically, the study of meteorology, in all its aspects, has gained new impetus from the introduction of machine methods. [...]
10

Water retention in clay soils by capillary and swelling forces.

Chang, Ren-Kong. January 1966 (has links)
Water in clay soils is considered to be held by capillary and swelling forces. Both forces are operative but the importance of each force depends upon the water content. This relationship was assessed from water retention, swelling pressure, and volume change studies using samples of different aggregate sizes compacted to different porosities. [...]

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