Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 60-61). Also available on the World Wide Web.

Bareroot, conventional containerized, and large potted EKOgrown® seedlings of water oak (Quercus nigra) and white oak (Q. alba) were planted on two Hurricane Katrina damaged sites in south Mississippi. After two growing seasons, white oak exhibited greater survival (61.1%) than water oak (48.8%) and greater height growth (WHO = 7.4 cm, WAO = 1.4 cm). Water oak had greater groundline diameter (GLD) growth (3.3 mm) and greater second-year height growth (WHO = 2.5 cm, WAO = 9.6 cm). Second-year development could lead to greater height growth by water oak. Bareroot seedlings outperformed other planting stocks in survival and height growth, but EKO seedlings exhibited greater GLD growth. Even though EKO seedlings had greatest GLD growth, they exhibited the least overall height growth of all planting stocks (1.9 cm). Based on seedling cost and performance in this study, planting bareroot seedlings are the most efficient method to artificially regenerate oak forests.

Genetic improvement has been an integral part of loblolly pine plantation forestry in southern United States for about 60 years with focus on improving timber yield, wood quality, and pest and disease resistance. Advances in techniques of genetic selection, breeding, and propagation of planting material have made it possible to achieve genetic gains that are likely to result in significant changes in loblolly pine stand dynamics. Height-age relationships, height and diameter relationships and distributions, and intraspecific competition were investigated in second generation open-pollinated, controlled-pollinated, and clonal loblolly pine with an objective of characterizing the nature and magnitude of changes in these characteristics due to genetic improvement and clonal forestry. Genetic improvement and/or clonal forestry had no practical effect on parameters of the height-age and height-diameter relationships beyond the effect on the asymptote parameter of the Chapman-Richards and Korf equations that were used to model these relationships. Genetic improvement resulted in an increase in the mean of height distribution without a corresponding increase in the mean of the diameter distribution, but had no effect the variance and skewness of the distributions. Thus, growth and yield models in which basal area is a function of height at a specific age (site index) are likely to over predict genetic gains in basal area growth and volume yield. Increase in stand density resulted in an increase in variance of the diameter distribution of non-clonal stands but had no effect on the variance of the diameter distribution of clonal stands. Thus, diameter distribution of clonal stands may differ from that of non-clonal stands after crown closure despite the distributions not being different before and during early stages of crown closure. This study also evaluated methods that may be used to predict height growth of new genetic varieties and those that may be used to asses intraspecific competition in forest stands. Mixed-model approach of calibrating a height-age relationship to a new loblolly pine clone gave biased estimates for clones that were at the extremes of the distribution of the groups. The use of maximum likelihood with simulated annealing (MLSA) to evaluate competitive interactions among trees in loblolly pine stands gave non-unique estimates of optimum competitor selection radius. A simpler technique that uses Pearson correlations was proposed and was found to work better than MLSA. / Ph. D.

Hydraulic fracturing plays an important role in increasing production rate in tight reservoirs. The performance of the reservoir after fracturing can be observed from the productivity index. This parameter is dependent on the fracture geometry; height, length and width. Unified fracture design (UFD) offers a method to determine the fracture dimensions providing the maximum productivity index for a specific proppant amount. Then, in order to achieve the maximum productivity index, the treatment schedules including the amount of liquid and proppant used for each stage must be determined according to the fracture dimensions obtained from the UFD. The proppant number is necessary for determining the fracture geometry using the UFD. This number is used to find the maximum productivity index for a given proppant amount. Then, the dimensionless fracture conductivity index corresponding to the maximum productivity index can be computed. The penetration ration, the fracture length, and the propped fracture width can be computed from the dimensionless fracture conductivity. However, calculating the proppant number used in UFD requires the fracture height as an input. The most convenient way to estimate fracture height to input to the UFD is to assume that the fracture height is restricted by stress contrast between the pay zone and over and under-lying layers. In other words, the fracture height is assumed to be constant, independent of net pressure and equal to the thickness of the layer which has the least minimum principal stress. However, in reality, the fracture may grow out from the target formation and the height of fracture is dependent on the net pressure during the treatment. Therefore, it is necessary to couple determination of the fracture height with determination of the other fracture parameters. In this research, equilibrium height theory is applied to rigorously determine the height of fracture. Solving the problem iteratively, it is possible to incorporate the rigorous fracture height determination into the unified fracture design.

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The goal of this thesis is to develop a procedural terrain height map generator programmable using a Turing complete scripting language. The generator must allow rendering of partial maps by generating arbitrary rectangular region of the map described by any script. The thesis explains why this means the traditional script execution model won't work in this case and proposes a novel two stage model, which executes the scripts in two stages - a simulation stage and a rendering stage. Powered by TCPDF (www.tcpdf.org)

Faculty of Health Sciences Degree of Master of Science in Physiotherapy 9601486g / A study was conducted to determine the optimum position of the handlebar on the Johnny G. Spinning® bicycle to reduce low back pain in cyclists participating in a Spinning® class. A three period open label cross over design, involving thirty six subjects was conducted. Each subject participated in three Spinning® classes with a different handlebar height at each session. The saddle angle, saddle post height and fore/aft position of the saddle remained fixed to eliminate variability. The cyclists’ pain perception was measured via the Visual Analogue Scale, Lickert Scale and the McGill Pain Questionnaire. The results were analysed with respect to the change in the mean and standard deviation of the Visual Analogue Scale, the Lickert scale and the McGill Pain Questionnaire. The significance of the study was set at the 0.05 level. A zero value was recorded with respect to pain experienced by the cyclists during a Spinning® class on the VAS, Lickert scale and on the McGill Pain scale, when the handlebars were placed in the high handlebar height position on the Spinning® bicycle; this is the most important outcome of the study conducted. In conclusion, there is a statistically meaningful difference (p<0.001) between the mean values of pain recorded by participants of the low handlebar height compared to the normal handlebar height, with the normal handlebar height being the better position. The standard deviation remains relatively constant. No pain was recorded on the VAS, Lickert scale and on the McGill Pain scale when the handlebars were placed in the high handlebar height position on the Spinning® bicycle. The results of the study indicate that the high handlebar height position is the best position for participants in a Spinning® class.

Faculty of Engineering & Built Environment, School of Electrical & Info Engineering, Dissertation / The primary objective of this paper is to present results regarding data obtained from Eskom’s Lightning Positioning and Tracking System (LPATS) and is a continuation of the work presented at the two SAUPEC Conferences in Pretoria and Stellenbosch [1, 2]. LPATS provides some useful information regarding the lightning field measurements around the Brixton and Hillbrow Towers, in Johannesburg, for the two seasons of June 2001 to June 2003. The results suggest that there is a significant increase in apparent ground flash density in the vicinity of the towers when compared to the surrounding areas. The observation of mean current values in the order of -20kA suggests that the increased contribution of upward flashes to the total incidence of flashes in tall structures should lead to a decrease in measured current amplitudes.