Thesis (M.S.)--Ohio University, August, 1999. / Title from PDF t.p.

Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 1, 2009) Vita. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xx, 161 p.; also includes graphics Includes bibliographical references (p. 153-161). Available online via OhioLINK's ETD Center

No description available.

Although sulphur is one of the more abundant elements present in plants, its importance as a plant nutrient has been underestimated until comparatively recently. Scientific literature over the past few years, however, shows that interest in the determination of sulphur in natural waters, soil and plant materials has been renewed. Perhaps the main reason for the non-recognition of the importance of sulphur as a plant nutrient is the fact that sulphur-deficiency seldom occurs since sufficient sulphur is usually added to the soil in rainfall (particularly near industrial towns) to supply all the sulphur requirements of plants. In addition, sulphur is frequently present in fertilizers added to soils to counteract deficiency in other elements, especially phosphorus. Superphosphates, for example contain up to 60%, gypsum. Sulphur is also added to the soil in some instances in order to reduce the soil pH, the elemental sulphur being fairly readily oxidised in the soil to sulphuric acid. The organic fraction in the soil also contains sulphur.

A study was undertaken to determine some of the factors which affected the extraction of sulphur from seven selected soils of the Lower Fraser Valley and Vancouver Island; with particular reference to the effect of pH, concentration and cation of phosphate buffers. In all cases the presence of phosphate resulted in more sulphur being extracted, than extraction with water only. In every instance increasing the concentration of neutral sodium phosphate buffers from 0.005M to 0.5M resulted in increasing sulphur extraction. Using a 0.5H sodium phosphate buffer and increasing the pH from 4 to 8 generally resulted in maximum extraction at pH 7, except notably in the Langford soil in which the amount of sulphur extracted increased as the pH was changed from 4 to 8. The behaviour of four surface soils when extracted with 0.5M sodium phosphate at varying pH levels was quite similar, the mineralogy of the <2µ fraction was also similar. Gel filtration studies of the 0.5M phosphate extracts of the Langford showed that at pH 4 little inorganic sulphate was extracted, while from pH 6 to 8, the amount extracted remained almost constant, though more than three times that extracted at pH 4. The extracted organic fraction increased as the pH varied from 4 to 8. In soils with a low carbon content and a high content of free iron and aluminum oxides, the water extractable sulphur was very low, as was the amount of phosphate extractable organic sulphate. The amount of sulphate extracted from the original air dry samples by 0.5M phosphate was very much less than the sulphate adsorbed from a 50 ppm sulphur solution. It was found that a neutral 0.5M sodium phosphate solution extracted more sulphur in nearly all cases, than other extractants, and in the soils studied cold water did not seem suitable. The neutral 0.5M phosphate solution extracted inorganic and a portion of the organic sulphate and may be expected to be a suitable chemical extractant which will be able to indicate the sulphur status of soils of the Lower Fraser Valley. / Land and Food Systems, Faculty of / Graduate

A study was undertaken to determine some of the factors which affected the extraction of sulphur from seven selected soils of the Lower Fraser Valley and Vancouver Island; with particular reference to the effect of pH concentration and cation of phosphate buffers. In all cases the presence of phosphate resulted in more sulphur being extracted, than extraction with water only. In every instance increasing the concentration of neutral sodium phosphate buffers from 0.005M to 0.5M resulted in increasing sulphur extraction. Using a 0.5M sodium phosphate buffer and increasing the pH from 4 to 8 generally resulted in maximum extraction at pH 7, except notably in the Langford soil in which the amount of sulphur extracted increased as the pH was changed from 4 to 8. The behaviour of four surface soils when extracted with 0.5M sodium phosphate at varying pH levels was quite similar, the mineralogy of the <2μ fraction was also similar. Gel filtration studies of the 0.5M phosphate extracts of the Langford showed that at pH 4 little inorganic sulphate was extracted, while from pH 6 to 8, the amount extracted remained almost constant, though more than three times that extracted at pH 4. The extracted organic fraction increased as the pH varied from 4 to 8. In soils with a low carbon content and a high content of free iron and aluminum oxides, the water extractable sulphur was very low, as was the amount of phosphate extractable organic sulphate. The amount of sulphate extracted from the original air dry samples by 0.5M phosphate was very much less than the sulphate adsorbed from a 50 ppm sulphur solution. It was found that a neutral 0.5M sodium phosphate solution extracted more sulphur in nearly all cases, than other extractants, and in the soils studied cold water did not seem suitable. The neutral 0.5M phosphate solution extracted inorganic and a portion of the organic sulphate and may be expected to be a suitable chemical extractant which will be able to indicate the sulphur status of soils of the Lower Fraser Valley. / Land and Food Systems, Faculty of / Graduate

No description available.

No description available.

The kinetics of the reaction of atomic sulfur and nitrogen dioxide have been investigated over the temperature range 298 to 650 K and pressures from 14 - 405 mbar using the laser flash photolysis - resonance fluorescence technique. The overall bimolecular rate expression k (T) = (1.88 ± 0.49) x10-11 exp-(4.14 ± 0.10 kJ mol-1)/RT cm3 molecule-1 s-1 is derived. Ab initio calculations were performed at the CCSD(T)/CBS level of theory and a potential energy surface has been derived. RRKM theory calculations were performed on the system. It is found that an initially formed SNO2 is vibrationally excited and the rate of collisional stabilization is slower than the rate of dissociation to SO + NO products by a factor of 100 - 1000, under the experimental conditions.