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This thesis research was conducted to test the hypothesis that the survival and growth of both neonatal and postweaning piglets can be improved by nutritional modulations. Two experiments were carried out to 1) evaluate effects of birth weight on mortality, growth performance, and efficiency of sow-reared piglets; and 2) determine the effects of a phytochemical (Yucca schidigera) on growth performance of postweaning pigs. In the first experiment, piglets (n=160) from 18 multiparous sows (Landrace X Large White) were used. Body weight of all piglets were recorded immediately after birth, d 7, d 14, d 21 and d 35 of their age. Individual milk consumption of piglets was estimated using the weigh-suckle-weigh method. Average daily gain and mortality were recorded. To analyze the effects of birth weight on future BW and growth, piglets were classified based on their birth weight into four categories of A: 0.7-1.09 kg, B: 1.10-1.49 kg, C: 1.50-1.89 kg and D: >1.90. Data were statistically analyzed using one-way ANOVA. Results indicated that low birth weight of pigs not only increased (P < 0.05) their incidence of mortality but also negatively impacted (P < 0.05) their whole-body growth. Interestingly, surviving low-birth-weight piglets had a higher (P < 0.05) rate of efficiency to utilize milk nutrients for growth than larger littermates. In the second experiment, two 21-day trials using 21-d-old postweaning piglets (n=111) were performed (d 21 to 42 of age). In the first trial, pigs were assigned to one of the three groups fed diets supplemented with 0 (control), 120 ppm or 180 ppm of Yucca powder (BIOPOWDER). The second trial was conducted as the first trial except that the basal diet contained 0.2 percent L-citrulline (an effective precursor of arginine). Body weight, average daily gain and feed intake of all pigs were measured weekly in both trials. At the last day of experiment, 2 h after the last meal, jugular blood samples were taken from all pigs in both trials for amino acid analysis. One-way ANOVA was used to statistically analyze the data. When the basal diet did not contain citrulline, dietary supplementation with BIOPOWDER did not affect (P > 0.05) any of the measured variables related to growth performance. However, supplementing an appropriate dose of this yucca extract (120 ppm) to a citrulline-fortified diet increased growth performance and feed efficiency in these animals. Adequate availability of arginine is required for BIOPOWDER to exert its anabolic effect on piglet growth and its regulatory action on improving the efficiency of nutrient utilization in young pigs. These findings have important implications for nutritionally modulating the growth of neonatal pigs and, therefore, the swine industry worldwide.

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The study of the subsurface flow and distribution of water is critical to the evaluation of the unsaturated zone for a potential geologic high-level radioactive waste repository. This site is located at Yucca Mountain, Nevada in the northern Mojave Desert. and was chosen on the basis of its low precipitation, deep unsaturated zone, and layered volcanic rocks providing the potential for natural hydraulic barriers to reduce the downward percolation of water through the waste storage area. The detailed characterization of hydrologic properties is necessary to evaluate the mechanisms responsible for the distribution and flow of water in the unsaturated zone. Analyses in this study have provided detailed hydrogeologic units with unique hydrologic properties and hydraulic parameters. Porosity was determined to be a useful physical property for predicting hydraulic parameters, as it relates to the largescale deterministic processes that created the volcanic rocks. The detailed property dataset, along with field measurements of moisture status, temperature, and chemistry, were used to evaluate the potential for lateral diversion in the rocks above the potential repository. It was determined that lateral diversion is a small-scale process in this natural system. On the basis of analyses performed in this study, it is suggested that large-scale diversion is not likely to occur at this site. This mechanism should not, therefore, be relied upon to perform as a natural hydraulic barrier to flow reducing percolation through the unsaturated zone. / Graduation date: 2002

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Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 24, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation supervisors: Dr. William H. Miller, Dr. Brady D. Hanson. Vita. Includes bibliographical references.

Thesis (Ph. D.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references.

Yucca Mountain was designated as the proposed high-level radioactive waste repository by the U.S. Government in 1987. The proposed repository design requires high safety for a long maintenance period of 10,000 years. To satisfy this requirement, evaluation of the influence of earthquakes on the repository is necessary. Prediction of earthquake-induced ground motions around the repository requires knowledge of the dynamic properties of the geologic materials around the repository. The main geologic materials in the vicinity of Yucca Mountain are tuffs (ignimbrites) which are formed by the deposition of volcanic ash mixed with erupted volcanic gas, water vapor and pyroclastic material. Two types of dynamic tests, (1) the free-free, unconfined, resonant column and direct arrival test (freefree URC test) and (2) the fixed-free resonant column and torsional shear test (fixed-free RCTS test), were used to measure the dynamic properties of tuffs. The emphasis in this dynamic testing was evaluation of shear modulus (G) and material damping ratio (D) of the tuffs in the small-strain (linear) and mildly nonlinear (to strains of about 0.02 %) ranges. To evaluate the influence of various parameters on G and D of tuffs, correlations with other features such as total unit weight, porosity and stratigraphic unit were performed and general relationships between them are proposed. In addition, an unconfined, slow-cyclic torsional shear (CTS) device was developed and used to measure the cyclic shear properties of the tuffs from Yucca Mountain at larger strain amplitudes than possible in the fixed-free RCTS tests. Additionally, the CTS device was also used to determine the shear failure strength of the tuffs. By combining the cyclic shear properties of the tuffs from the CTS tests and the dynamic properties of the tuffs from the fixed-free RCTS tests, complete dynamic property curves from small-strain to failure strain were evaluated. / text

Yucca Mountain was designated as the proposed high-level radioactive waste repository by the U.S. Government in 1987. The proposed repository design requires high safety for a long maintenance period of 10,000 years. To satisfy this requirement, evaluation of the influence of earthquakes on the repository is necessary. Prediction of earthquake-induced ground motions around the repository requires knowledge of the dynamic properties of the geologic materials around the repository. The main geologic materials in the vicinity of Yucca Mountain are tuffs (ignimbrites) which are formed by the deposition of volcanic ash mixed with erupted volcanic gas, water vapor and pyroclastic material. Two types of dynamic tests, (1) the free-free, unconfined, resonant column and direct arrival test (freefree URC test) and (2) the fixed-free resonant column and torsional shear test (fixed-free RCTS test), were used to measure the dynamic properties of tuffs. The emphasis in this dynamic testing was evaluation of shear modulus (G) and material damping ratio (D) of the tuffs in the small-strain (linear) and mildly nonlinear (to strains of about 0.02 %) ranges. To evaluate the influence of various parameters on G and D of tuffs, correlations with other features such as total unit weight, porosity and stratigraphic unit were performed and general relationships between them are proposed. In addition, an unconfined, slow-cyclic torsional shear (CTS) device was developed and used to measure the cyclic shear properties of the tuffs from Yucca Mountain at larger strain amplitudes than possible in the fixed-free RCTS tests. Additionally, the CTS device was also used to determine the shear failure strength of the tuffs. By combining the cyclic shear properties of the tuffs from the CTS tests and the dynamic properties of the tuffs from the fixed-free RCTS tests, complete dynamic property curves from small-strain to failure strain were evaluated.