Call number: LD2668 .T4 1984 L37 / Master of Science

The falling film flow of milk was studied both analytically and experimentally. Experiments were carried out for concentrations from 19.93% to 62.09% to obtain the rheological data of milk while analytical studies were done to derive the solutions of the problem. Studies which include calculations and simulations were carried out for a typical milk flow in a falling film evaporator. It was found that milk was non-Newtonian at high concentrations and Herschel-Bulkley model was able to model the milk flow. The typical falling film flow was able to be simulated as a two phase flow in COMSOL to gain a better understanding of the flow. It was found that there were counter-current flow between the film and air in the evaporator. A Matlab program was also used to study the analytical solutions of the film temperature change while it flows down the tube with results showing that heat transfer was not linear as would have believed. Results from several experiments also enabled the change of milk viscosity with time to be modeled. Milk viscosity increased steadily with time and higher at higher total solids from 35.47% to 49.25% for three hours. Calculations revealed that film thickness of milk was very thin, from 0.00116 m at the entrance of tube to 0.00146 m at the tube exit. From the use of models developed of the rheological parameters, results showed that these parameters have impacts on film flow except the yield stress. However, the viscosity and yield stress are factors that will limit the operating range available for falling film evaporator.

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The Upper Devonian Grosmont reservoir in Alberta, Canada, is the single largest carbonate bitumen reservoir in the world, with an estimated 400 billion barrels of bitumen in place. The Grosmont bitumen formed from light crude oil via extensive biodegradation, which produced extremely high in-situ viscosities of >1 million cP. Forty nine samples from fifteen wells were selected for rheological behavior, viscosity, and biodegradation pattern analysis. In addition, various methods of viscosity determination were compared. Results indicate that the Grosmont bitumen is essentially a non-Newtonian fluid at in-situ conditions, exhibiting a distinctive shear-thinning behavior at T < 40C. Neglecting this character will cause inaccurate viscosity measurements. The viscosity variations in the Grosmont reservoir are cyclic with depth and are stratigraphically controlled. The bitumen exhibits 3 levels of biodegradation. Biodegradation parameters from hopanes and tricyclic terpanes may potentially be used for bitumen quality prediction.

Viscosity and fermentability are considered important properties of dietary fiber. Viscosity increases digesta viscosity and reduces digesta passage rate, nutrient digestion and absorption whereas fermentability increases fermentation into short chain fatty acids (SCFA). The objectives were to enhance the understanding of these properties of dietary fiber and their effects on digestive physiology using surgical models in pigs. In study 1, three catheterized pigs fed 3 diets containing 0, 3, or 6% oat -glucan concentrate (BG0, BG3, and BG6) in a repeated 3 3 Latin square. Pigs fed BG6 had a lower net glucose flux. Pigs fed BG6 tended to have lower portal C-peptide without lowered insulin. Pigs fed BG6 had lower portal glucose dependent insulinotropic peptide (GIP) and glucagon like peptide-1 (GLP-1), which in turn were correlated (R2 = 0.81 and 0.88, respectively) with portal glucose. Pigs fed BG3 and BG6 had a higher net SCFA flux, indicating increased fermentation. In study 2 and 3, ileal cannulated grower pigs were fed semi-purified diets supplemented with 5% purified non-starch polysaccharides (NSP) in a 2 (low and high viscous) 2 (low, and high fermentable) factorial arrangement using cellulose (CEL), carboxymethylcellulose (CMC), and low and high viscous oat -glucan (LBG and HBG, respectively). The CMC, LBG and HBG induced high ileal digesta viscosity coinciding with high nutrient digestibility; in contrast, CEL had lowest viscosity and nutrient digestibility. The CEL, LBG and HBG increased fecal SCFA. Linear discriminate analysis of NSP and TRFLP profiles and 16S rRNA gene copy numbers of bacterial groups revealed that CMC resulted in distinctive bacterial communities. The gene copy number of butyryl-CoA CoA transferase was higher than for butyrate kinase, indicating that this pathway is dominant for butyrate production in pigs. In study 4, similar dietary treatments were fed to catheterized pigs. High viscous and fermentable HBG increased net butyrate flux and insulin and GLP-1 production but did not affect net glucose flux. Thus, the viscosity and fermentability are important functional properties of dietary fiber that better explained the physiological effects on kinetics of digestion, absorption, hormones responses, fermentation and thus nutrient flow and intestinal health. / Animal Science

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