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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.
331

Movement of radionuclides through unsaturated soils

de Sousa, Fernando Nuno 05 1900 (has links)
No description available.
332

Effects of ion concentration on the force field controlling the transmission of water through clay soils.

Paul-Douglas, Gabrielle. January 1969 (has links)
No description available.
333

Soil moisture and tensiometer measurements made to assist the management of supplementary irrigation of maize in eastern Ontario

Ibarra, Sandra. January 1997 (has links)
Field experiments were conducted in 1996, to evaluate the need of supplemental irrigation of maize on some sandy soils in Eastern Ontario. Field and laboratory measurements of soil properties were conducted. Plow layer and deficit irrigation management approaches were evaluated. Irrigation requirements using rain and evaporation data of the humid 1996 summer, as well as data from the drier 1974 summer, were evaluated. The results show that using a root zone depth less than 300 mm led to more water losses by drainage, more irrigation water requirements and more frequent irrigation applications, as compared to using a 400 mm root zone. Therefore, it is recommended that a 400 mm root zone depth be used for scheduling irrigation applications of 25 mm. Wilting began to appear at 60% soil moisture depletion. Thus, 50% moisture depletion is suggested as the time to start irrigation to avoid crop stress. / The principal assumptions for tabulation of irrigation scheduling were: (1) That the soil is at field capacity at the beginning of June; and (2) That upward flux from a water table is negligible, since the summer water table is deeper than 2 m. These assumptions are based on the facts that rain in May keeps the soil moist, the maize is small at the end of May and that AET (Actual Evapotranspiration) is less than PET (Potential Evapotranspiration). / The measurements show that soil moisture depletion varies from site to site within the fields. The water balance was calculated using weather data and available soil moisture holding capacities for three locations on the farm. The tensions that the plant roots exerted to obtain water from the soil were measured with tensiometers and tabulated as a guide for irrigation management.
334

Evaluation of commercially available moisture-sensing devices to monitor feather wetness

2015 March 1900 (has links)
The ability to detect moisture in broiler feathers for five moisture-sensing devices using varying techniques, an infrared (IR) camera, and one type of moisture-sensitive paper was evaluated in two experiments; using artificial feather beds in laboratory settings and in field conditions using live birds. In the first experiment (lab testing-phase I), seven levels of moisture were applied once per day to the swatches with four different feather densities to account for moisture variation and feather density present in commercial barn conditions. True moisture of the feathers was determined gravimetrically on a daily basis. Using the five devices, 20 readings each were acquired from each of the swatches. The average temperatures of a selected area from images captured using an IR camera along with average device readings were compared with the true moisture content. Moisture-sensitive paper images were analyzed in Photoshop and Matlab prior to statistical analysis. Data from all devices, the IR camera, and moisture-sensitive paper were analyzed using SAS Procedure GLM to define relationships between the true moisture content and the readings. The devices were analyzed based on their accuracy, consistency and sensitivity using adjusted-R2, standard error, and regression slope, respectively. The data from all devices and techniques were significantly correlated with feather swatch moisture content (P<0.05). Results from the first experiment suggested potential to measure feather moisture by several of the tested devices. While feather density presented as a challenge during this experiment, it was not considered as a significant issue when evaluating the devices. The “Hay” and “Construction 1” sensors showed the most promise in detecting feather moisture and iv were selected for further testing using live birds. The two devices had relatively higher accuracy, consistency, and sensitivity compared to other devices and techniques. The second experiment (field testing – phase II) evaluated the two selected devices (Hay and Construction 1 sensors) in various commercial broiler settings. Device readings were acquired from the back, wing, and breast feathers. A sample of back feathers from each bird was collected to determine the true moisture. Statistical analyses of data were the same as in experiment 1. Although the initial study, conducted within a lab setting, denoted a significant relationship between true moisture content and device readings, testing within the field environments showed the devices to perform poorly. Readings from both devices and for all the locations tested demonstrated a lack of sensitivity, accuracy, and consistency for measuring moisture in feathers of live birds.
335

CHARACTERIZATION OF INFLUENCE OF MOISTURE CONTENT ON MORPHOLOGICAL FEATURES OF SINGLE WHEAT KERNELS USING MACHINE VISION SYSTEM

Ramalingam, Ganesan 08 April 2010 (has links)
The main objective of this study was to quantify changes in physical features of western Canadian wheat kernels caused by moisture increase using a machine vision system. Single wheat kernels of eight western Canadian wheat classes were conditioned to 12, 14, 16, 18, and 20% (wet basis) moisture content, one after another, using headspaces above various concentrations of potassium hydroxide (KOH) solutions which regulated relative humidity. A digital camera of 7.4 x 7.4 μm pixel resolution with an inter-line transfer charge-coupled device (CCD) image sensor was used to acquire images of individual kernels of all samples. A machine vision algorithm developed at the Canadian Wheat Board Centre for Grain Storage Research, University of Manitoba, was implemented to extract 49 morphological features from the wheat kernel images. Of the 49 morphological features, 24, 11, 7, 21, 26, 11, 17, and 9 features of Canada Western Red Spring, Canada Western Amber Durum, Canada Prairie Spring White, Canada Prairie Spring Red, Canada Western Extra Strong, Canada Western Red Winter, Canada Western Hard White Spring, and Canada Western Soft White Spring wheat kernels, respectively, were significantly (α=0.05) different as the moisture content increased from 12 to 20%. Generally the basic morphological features such as area, perimeter, major axis length, minor axis length, maximum radius, minimum radius, and mean radius were linearly increased with increase in moisture content. In all cases the moment and Fourier descriptor features decreased as moisture content increased from 12 to 20%.
336

CHARACTERIZATION OF INFLUENCE OF MOISTURE CONTENT ON MORPHOLOGICAL FEATURES OF SINGLE WHEAT KERNELS USING MACHINE VISION SYSTEM

Ramalingam, Ganesan 08 April 2010 (has links)
The main objective of this study was to quantify changes in physical features of western Canadian wheat kernels caused by moisture increase using a machine vision system. Single wheat kernels of eight western Canadian wheat classes were conditioned to 12, 14, 16, 18, and 20% (wet basis) moisture content, one after another, using headspaces above various concentrations of potassium hydroxide (KOH) solutions which regulated relative humidity. A digital camera of 7.4 x 7.4 μm pixel resolution with an inter-line transfer charge-coupled device (CCD) image sensor was used to acquire images of individual kernels of all samples. A machine vision algorithm developed at the Canadian Wheat Board Centre for Grain Storage Research, University of Manitoba, was implemented to extract 49 morphological features from the wheat kernel images. Of the 49 morphological features, 24, 11, 7, 21, 26, 11, 17, and 9 features of Canada Western Red Spring, Canada Western Amber Durum, Canada Prairie Spring White, Canada Prairie Spring Red, Canada Western Extra Strong, Canada Western Red Winter, Canada Western Hard White Spring, and Canada Western Soft White Spring wheat kernels, respectively, were significantly (α=0.05) different as the moisture content increased from 12 to 20%. Generally the basic morphological features such as area, perimeter, major axis length, minor axis length, maximum radius, minimum radius, and mean radius were linearly increased with increase in moisture content. In all cases the moment and Fourier descriptor features decreased as moisture content increased from 12 to 20%.
337

Investigation of Soil Moisture - Vegetation Interactions in Oklahoma

Ford, Trenton W. 02 October 2013 (has links)
and-atmosphere interactions are an important component of climate, especially in semi-arid regions such as the Southern Great Plains. Interactions between soil moisture and vegetation modulate land-atmosphere coupling and thus represent a crucial, but not well understood climate factor. This study examines soil moisture-vegetation health interactions using both in situ observations and land surface model simulations. For the observational study, soil moisture is taken from 20 in situ Oklahoma Mesonet soil moisture observation sites, and vegetation health is represented by MODIS-derived normalized difference vegetation index (NDVI). For the modeling study, the variable infiltration capacity (VIC) hydrologic model is employed with two different vegetation parameterizations. The first is the model default vegetation parameter which is interannually-invariant leaf area index (LAI). This parameter is referred to as the control parameter. The second is MODIS-derived LAI, which captures interannual differences in vegetation health. Soil moisture simulations from both vegetation parameterizations are compared and the VIC-simulated soil moisture’s sensitivity to the vegetation parameters is also examined. Correlation results from the observation study suggest that soil moisture-vegetation interactions in Oklahoma are inconsistent, varying both in space and time. The modeling results show that using a vegetation parameterization that does not capture interannual vegetation health variability could potentially result in dry or wet biased soil moisture simulations.
338

Evaluation of Moisture Susceptibility of Warm Mix Asphalt

Garcia Cucalon, Maria Lorena 03 October 2013 (has links)
Economic, environmental and engineering benefits promote the rapid implementation of WMA technologies. However, concerns remain based on changes in the production process that may lead to moisture susceptibility in the early life as compared to HMA. To evaluate WMA moisture susceptibility during this critical period, standard laboratory tests were used for three field projects each with an HMA control mixtures and multiple WMA mixtures. Different specimen types were also evaluated to capture differences in mix design, quality control/quality assurance, and field performance. Specimens were evaluated for moisture susceptibility by Indirect Tensile (IDT) Strength, Resilient Modulus (MR) and Hamburg Wheel-Track Testing (HWTT). Specimens for IDT and MR were tested dry and then tested wet after conditioning as described in AASHTO T283 with one freeze-thaw cycle. HWTT was used to assess both moisture susceptibility and rutting potential under repeated loads in the presence of water at elevated temperatures (i.e., 122°F [50°C]), and the output parameters used for evaluation were the calculated Stripping Inflection Point (SIP) and the rut depth at 5000 load cycles. Based on the results of the laboratory tests performed on PMFC cores acquired at construction and with time, WMA during its early life exhibited inferior moisture resistance when compared to HMA. However, with time, specifically after one summer, the dry and wet properties of WMA became equivalent to those of HMA. For WMA constructed in the fall, the results from this study suggest that the inclusion of recycled asphalt pavement (RAP) or an anti-stripping agent may alleviate possible moisture susceptibility issues in the early life during wet, winter weather conditions. While some laboratory test results demonstrated that WMA is more moisture susceptible than HMA, field performance reported to date from the three projects used in this study shows no evidence of moisture damage. Therefore the search for a laboratory test to screen mixtures for moisture susceptibility continues. An alternative approach, applying Griffith crack growth theory and utilizing IDT, MR and air voids% the adhesive bond energy of asphalt mixtures was calculated for Texas field project. This value holds promise for characterizing performance of asphalt mixtures by considering basic properties and grouping into one representative value.
339

Temporal variability of soil hydraulic properties subsequent to tillage

Mapa, Ranjith Bandara January 1984 (has links)
Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1984. / Bibliography: leaves [187]-199. / Microfiche. / xvii, 199 leaves, bound ill. 29 cm
340

Influence of soil structure on water retention, water movement and thermodynamic properties of adsorbed water

Sharma, Munna Lal January 1966 (has links)
Typescript. / Thesis (Ph. D.)--University of Hawaii, 1966. / Bibliography: leaves 178-190. / xv, 190 l illus., tables

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