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Polymeric materials have attracted a lot of attention for the past several decades. Different sectors of manufacturing industry, such as packaging, building and automotive industry have introduced polymeric materials in their applications. Common polymer manufacturing processes include thermoforming and blow molding. In this research, characteristics of a new polymer manufacturing process, referred to as axial-feed hot gas tube forming (HGTF) are studied. Experimental studies were conducted to form a simple axisymmetric component from extruded polypropylene (PP) tube by varying several key process parameters such as internal pressure, temperature and axial feed. Tube shape and deformation characteristics were studied as a function of the above process parameters. In addition, two consecutive material models have been utilized for finite element simulation of axial-feed HGTF of PP tube using a commercial FE code. One of them is conventional hyperelastic Ogden material model and another is more advanced viscoelastic-viscoplastic Augmented Hybrid material model (AHM), that has been recently developed. Simulation results from two models were analyzed and compared with the experimental results and good general agreement has been obtained. Results showed that application of more advanced AHM material model led to improved prediction of part shape and strain distribution over the part profile. / Thesis / Master of Applied Science (MASc)

Zearalenone (ZEN) is an estrogenic mycotoxin produced by fungi in the genus Fusarium. Fusarium species commonly occur in cereal crops such as corn, wheat, barley, and rice which are used in swine feed. In addition to cereals, co-products of ethanol distillation, brewing, and baking are frequently re-purposed as swine feed. ZEN contamination has been related to severe reproductive issues including pelvic organ prolapse (POP), which describes the displacement of pelvic floor organs from their healthy anatomical positions. A recent rise in the rate of POP in sows highlights a need for more information surrounding the occurrence of ZEN in swine feed and the possible role of ZEN in POP. This research aims to understand the relationship between ZEN contamination in swine feed and swine reproductive health. The primary objectives of this work are to (1) characterize the stress relaxation behavior of vaginal tissue in the swine model, (2) determine how ZEN consumption effects the elasticity of pelvic support tissue. (3) determine where ZEN and a related metabolite accumulate in the swine reproductive tract, (4) evaluate the prevalence of ZEN and related Fusarium mycotoxins in swine feed and ingredients, and (5) track ZEN and related Fusarium mycotoxins throughout production of beer and brewers' spent grains (BSG). Results from this work can help stakeholders to mitigate mycotoxin contamination in swine feed, evaluate swine for ZEN toxicosis, and provide care for animals experiencing POP. / Doctor of Philosophy / Under certain conditions, some fungi produce harmful toxins (mycotoxins) that can compromise the health of humans and animals. Mycotoxin-producing fungi are common in cereal crops such as corn, wheat, and barley which may be fed to humans or animals. Swine are especially sensitive to mycotoxins, making feed composition important for animal welfare and profitability. Zearalenone (ZEN) is a mycotoxin that behaves like estrogen, a hormone frequently associated with female reproductive health. Pelvic organ prolapse (POP) is a condition, common in women, wherein organs in the pelvic floor such as the vagina, rectum, and uterus, descend from their healthy anatomical position. Swine herds are experiencing higher rates of POP, which may be related to ZEN contamination in feed. The overall goal of this research is to understand the relationship between mycotoxin contamination in feed and swine reproductive health. The specific objectives of this research are to (1) characterize the mechanical properties of vaginal tissue in swine, (2) characterize mechanical properties of pelvic support tissue associated with POP, in swine fed ZEN, (3) determine which reproductive tissues which accumulate ZEN in swine, (4) evaluate the prevalence of ZEN and related mycotoxins in swine feed, and (5) track ZEN and related mycotoxins throughout production of beer and brewers' spent grain, a co-product used in animal feed. This research can help animal producers develop strategies to mitigate mycotoxin contamination in feed and improve veterinary care.

Beef cattle producers continuously search for nutritional management options that provide flexibility to production scenarios. Due to its positive effects on maternal productivity, early weaning is one such alternative strategy that has received considerable interest. To better understand the effects of early weaning on calf productivity, an extensive literature review and three experiments were conducted to evaluate the effects of early weaning on finishing feed efficiency, marbling development and retail product quality of beef steers. In experiment I, which included 90 Angus-sired steers from four calving seasons, early weaning followed by a short ad libitum concentrate-feeding and pasture-backgrounding phase reduced finishing residual feed intake (RFI) by 7 % (P < 0.0001) and increased carcass marbling score (MS) by 10 % (P < 0.01) when compared to conventionally weaned (CW) contemporaries. Similar effects were observed in experiment II, which included 28 Angus and Simmental-sired steers, as early weaning reduced RFI (P < 0.01) and increased carcass MS (P < 0.01). Lung mass of early weaned (EW) steers was greater than their CW contemporaries (P < 0.05), and was inversely related to RFI (R2 = 0.17; P < 0.05). Finishing treatments in this experiment included a high corn ration and an alternative low corn ration that iso-calorically replaced 50 % of the DM from corn with dried corn gluten feed. Iso-caloric replacement of corn reduced lung mass (P < 0.01), and when combined with the observed increase of EW steers suggests that lung development is affected by dietary energy type at various stages of growth. In experiment III, objective analyses of ribeye steaks obtained from steers included in experiment two revealed that early weaning increased cross-sectional muscle fiber area by 28 % (P < 0.001) and tended to increase (P = 0.08) Warner-Bratzler shear force by 36 %. Nonetheless, these effects were not great enough to alter un-trained consumer perception of texture (P ≥ 0.65), juiciness (P ≥ 0.55), flavor (P ≥ 0.25) or overall acceptability (P ≥ 0.34). Collectively, these results indicate that early weaning enhances finishing feed efficiency and carcass marbling without affecting un-trained consumer sensory perception. / Ph. D.

A controlled feeding experiment was conducted to compare the influence of barn-cured and field-cured alfalfa hay out from the same field on milk production and liveweight of dairy cows. Twelve Holstein cows were used in this trial. The double-reversal feeding method was followed. Grain was fed at the same rate to each group of cows. Hay was fed as the only source of roughage, and equal amounts of the two kinds of hay were fed to the two groups of cows. There was practically no difference in the total consumption of the two kinds of hay. Analysis of variance on the amounts of four per cent fat-corrected milk produced revealed highly significant differences at the one per cent level in favor of the barn-cured hay. The hays were sampled at regular intervals for proximate analysis. At the time of feeding the barn-cured hay contained .36 per cent more moisture, 2.63 per cent more protein, .26 per cent more fat, 1.20 per cent less fiber, 2.26 per cent less nitrogen-free extract, and .66 per cent more ash. The cows gained slightly in liveweight when they received the field-cured hay and lost slightly in liveweight when they received the barn-cured hay. Liveweight changes were not significant when analyzed statistically. / Master of Science

Typescript (photocopy). / Digitized by Kansas Correctional Industries