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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.
261

Alfalfa water-production functions under conditions of deficit irrigation with saline water

Pennington, Karrie Sellers,1949- January 1986 (has links)
This experiment was designed to determine the shape of the yield response function relating crop yield to total amount of saline irrigation water applied. Such a function contains a built-in leaching fraction that is the inevitable consequence of the inability of the plant to extract 100 % of the water from a saline soil. In order to define the production function and to determine the leaching fractions, alfalfa (Medicago sativa L. cv. 'Mesa Sirsa') was planted in soil columns in a greenhouse. Two experiments were run sequentially. These were irrigated with water of differing salinities. The first with an EC of 4 dS/m (1.4 bars) and the second with an EC of 8 dS/m (2.9 bars). Both solutions were prepared by adding equivalent amounts of sodium chloride and calcium chloride to distilled water. The treatment variables were amounts of irrigation water applied. The amounts in both experiments were 110%, 100%, 75%, 50% and 25% of the measured evapotranspiration (ET). Four crop harvests were made in each experiment. At the end of experiment 1, (approximately 120 days), one column from each treatment was destructively sampled for soil salinity and water content measurements. The remaining columns were similarly sampled at the end of experiment 2 (approximately 120 days). The crop-saline water production functions for both experiments were linear. Leaching fractions in experiment 1 were 9, 9, 6, 5 and 5% for treatments 1-5 respectively. Experiment 2 leaching fractions for treatments 1-5 respectively were 23, 25, 18, 15 and 17%. The lowest rootzone soil water osmotic potentials achieved by the end of experiment 1 for treatments 1-5 were -19, -20, -18, -26 and -24 bars. Corresponding treatment values achieved by the end of experiment 2 were -18, -22, -28, -31 and -45 bars.
262

SAMPLING VOLUME EFFECT ON MEASURING SALT IN THE SOIL PROFILE.

Hassan, Hesham Mahmoud. January 1982 (has links)
No description available.
263

GYPSUM AND AMMONIUM THIOSULFATE AS AMELIORATING AGENTS FOR SOILS IN ARIZONA.

Salih, Saad Mahdi. January 1982 (has links)
No description available.
264

EROSION AND RUNOFF FROM SODIUM DISPERSED, COMPACTED EARTH WATER HARVESTING CATCHMENTS.

Evett, Steven Roy. January 1983 (has links)
No description available.
265

CHLORIDE AND NITRATE DISTRIBUTION IN THE SOIL WITH FURROW AND BURIED DRIP IRRIGATION (SALINITY, SANDY LOAM)

Nava Leon, Jose Angel, 1956- January 1986 (has links)
No description available.
266

Nitrogen fixation by alfalfa as affected by salt stress and nitrogen levels

Zhou, Maoqian, 1961- January 1989 (has links)
The growth and Nitrogen fixation by one low salt tolerant alfalfa (Medicago sativa L.) and two germination salt tolerant selections inoculated with were investigated at two salt levels (0, -0.6 Mpa) and two N rates (1, 5ppm) using a system which automatically recirculates a nutrient solution. The high level of salinity (-0.6 Mpa osmotic potential of culture solution) resulted in substantial reduction in the N fixation percentage and total fixed N. The effect of salinity was more pronounced for later cuttings than for the earlier cutting. The N fixation percentages were substantially decreased by increasing N level and the reduction was enhanced by time. The N treatment levels did not exhibit a significant effect on total fixed N. Cultivars did not differ in either growth or N fixation. However, the interaction of N and salinity significantly decreased the percentage and amount of N fixation.
267

Structures and properties of magnetic molecular charge transfer salts

Martin, Lee January 1999 (has links)
No description available.
268

Mass spectrometry of organic and chlorometallated salts

Elaiwi, Ahmed Essa January 1994 (has links)
No description available.
269

Numerical simulation of hydrothermal salt separation process and analysis and cost estimating of shipboard liquid waste disposal

Hunt, Andrew Robert 06 1900 (has links)
CIVINS / Due to environmental regulations, waste water disposal for US Navy ships has become a requirement which impacts both operations and the US Navy's budget. In 2006, the cost for waste water disposal Navy-wide was 54 million dollars. There are many advanced waste water treatment technologies in the research and development stage at academic institutions, private corporations, and government labs. Additionally, considerable progress has been made in installing and operating unique waste water treatment systems onboard merchant and commercial vessels, showing that waste water treatment technologies are near the maturity level required for installation on US Navy ships. Installation and operations costs can be estimated from data collected from merchant ships, but the accompanying life cycle liquid disposal costs savings can be difficult to estimate. A cost estimator is presented which allows variations in ship's operational schedule and aids in determining the total life cycle savings, and the time for return on investment, when waste destruction technologies are installed in a class of ship. Additionally, the properties of one waste water destruction medium, supercritical water, are reviewed and its use in efficient and environmentally safe chemical processes are discussed. In particular, supercritical water is the medium of choice for the performance of a biomass to synthetic natural gas conversion process. The supercritical water is utilized to aid in a vital salt separation process which allows for efficient 4 hydrothermal gasification. Numerical simulations of the salt separation process are completed which help in understanding the flow properties. The results will aid in yielding an optimized salt separation process, improving the efficiency and viability of the conversion process. / CIVINS
270

Self-diffusion of Pb210 and Cl36 in Molten PbCl2-KCl Mixtures in the Region of the Compound 2PbCl2-KCl

Tidwell, Troy Haskell 06 1900 (has links)
The specific goal of the investigation was the measurement, as a function of temperature, of the self-diffusion coefficients of Pb210 and Cl36 in PbCl2-KCl compositions in the region of the first compound, and to calculate from these data the activation energy necessary for the diffusion of these ions.

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