Thesis (Ph. D.)--University of Wisconsin--Madison, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S. in environmental engineering)--Washington State University, May 2006. / Includes bibliographical references.

Thesis (Ph.D.)--York University, 2005. Graduate Programme in Earth and Space Science. / Typescript. Includes bibliographical references (leaves 186-196). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNR11559

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The low-rate trickling filter is the most common biological treatment process used in small and medium sized sewage works in the UK. It produces an inconsistent effluent quality, which has traditionally been related to seasonal changes in solids accumulation, grazing activity and sloughing of microbial film. The final effluent solids and, organic matter content is then too high for discharge or reuse. Given the increasingly stringent effluent standards, both in terms of quality and consistency, tertiary treatment is often required. This study was designed to investigate the key parameters affecting the performance of low-rate trickling filters and the characteristics of their effluents in terms of contaminant size, which might influence the efficiency of crossflow filtration as a tertiary treatment for the trickling filter.

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<p> Powder Metallurgy (P/M) offers a very efficient method to produce high volume, high throughput steel parts. The two most important property issues affecting P/M steels are: (I) possessing high mechanical properties despite having inherent internal porosity; (2) maintaining very tight dimensional tolerances during processing (sintering). Researchers are continually looking at ways to improve these two properties while keeping costs down. As in wrought and cast steels, in most applications P/M steels are alloyed; in P/M processing, alloys are typically added to Fe + C powder mixes as elemental powders. The entire mix of Fe+ C +elemental alloying additives are then consolidated under high pressure and sintered at high temperatures to strengthen the compact. The current work deals mainly with the the most commonly used alloying additives in P/M steels, Ni and Cu. </p> <p> While it is well-known that Ni and Cu do indeed improve the mechanical performance of steels and do affect the dimensional change of P/M parts in specific ways, for over 50 years the same standard Ni and Cu powders have been used in the industry. With new breakthroughs in the production of extra-fine metal powders (- 1-2 urn) P/M researchers now must examine the effect of particle size of alloying additions on the performance of sintered steels. Prior to the current work, significant documented work investigating the effect of particle size of Ni and Cu on the performance of P/M steels was very limited. </p> <p> The current work examined: (I) Ni powder particle size effects in P/M Ni steels; (2) Ni powder particle size effects in P/M Ni-Cu steels; (3) Ni and Cu powder particle size effects in P/M Ni-Cu-Mo steels. </p> <p> Specific focus was on determining the effects of particle sizes on the dimensional control and mechanical peformance of P/M steels. With both Ni and Cu, the finer the powder addition the better the dimensional control and mechanical performance of the steels. In steels containing both Ni and Cu, finer Ni also improved the distribution and diffusion of Cu. This suggested that there was a significant interaction between Ni and Cu during sintering which could be tailored to improve properties. The effect of changing Ni particle size on overall steel properties was significantly greater than the effect of changing Cu particle size. </p> <p> Mechanistic analyses via optical microscopy, SEM-EDX and E-SEM investigation, dilatometry, and differential thermal analysis were carried out to explain the results. Mathematical models were also developed to show the effect of Ni and Cu particle size on diffusion into the Fe matrix during sintering. </p> / Thesis / Master of Applied Science (MASc)

Broiler nutrition can be affected by many different factors, and diets can be made up of a wide variety of components. Feed enzymes, different Ca sources, and various ingredient particle sizes all contribute to broiler nutritional status and need to be investigated to determine their full effects on the bird. The objective of the first study was to evaluate various Ca sources and microbial phytases using an in vitro assay to simulate broiler digestion. The trial measured total Ca and P, soluble Ca and P, and pH. It involved limestone, dicalcium phosphate, highly soluble Ca (HSC), whey, and a control with no added Ca. Each diet was supplemented with 0 or 500 FTU/kg of phytase 1 or phytase 2. Diets were analyzed for total Ca and P and then were subjected to a gastric phase digestion, including the addition of HCl and pepsin, with incubation times of 5, 10, or 20 min. They were also subjected to a gastric phase and a SI phase digestion, including the addition of HCl, pepsin, NaHCO3, and pancreatin with incubation times of 5, 10, 20, or 60 min. The objective of the second study was to evaluate various particle sizes, Ca sources, and source locations using the same in vitro assay. Large, medium, and fine particle sizes, as well as limestone from 4 different locations and HSC were subjected to the same assays and conditions as in the first trial. These studies suggest that HSC is a highly soluble Ca source, phytase improves P solubility in vitro, fine particle size is more soluble than large particle size in vitro, and location from which the Ca source is obtained can affect Ca and P solubility. The in vitro assay utilized in this study is a fast and cost efficient technique for evaluating and comparing parameters of broiler diets to make recommendations for commercial poultry nutrition. / Master of Science

Master of Science / Food Science Institute / Fadi M. Aramouni / Jeffrey A. Gwirtz / In order to improve the quality of products available for consumers who require a gluten-free diet, this study examined the effects of sorghum flour composition and particle size on functionality in gluten-free batter bread. White, food-grade sorghum was milled to flour of varying extraction rates (60%, 80%, 100%), and was subsequently pin-milled at different speeds (no pin-milling, low- speed, and high-speed) to create flours of both variable composition and particle size. Two commercially-milled sorghum flour samples (AF and TV) were included in the study and subjected to the same pin-milling treatments. Characterization of each flour included measurements of flour composition, total starch content, particle size distribution, damaged starch, and water absorption. Bread characterization included measurement of specific volume, crumb properties, and crumb firmness through the use of digital imaging and texture profile analysis. Significant differences were found (p<0.05) in the composition of sorghum flours of varying extraction rate, most notably for fiber and total starch contents. Flour particle size and starch damage were significantly impacted by extraction rate and speed of pin milling (p<0.05). With the exception of the commercial flour samples, water absorption increased significantly with increasing extraction rate and speed of pin-milling speed (p<0.05). Within all treatments, breads produced from 60% extraction flour had significantly higher specific volumes, better crumb properties, and lower crumb firmness when compared to all other extractions and flour types. These measured bread characteristics were significantly impacted by flour properties, specifically particle size, starch damage, and fiber content (p<0.0001). The commercial flours studied produced breads of low specific volume, poor crumb properties, and dense textures. These results can assist millers and product developers in advancing the quality of sorghum-based gluten-free foods for the consumers that require them. Further research is necessary to better understand the extent to which particle size, and therefore starch damage, can improve sorghum-based gluten-free breads.