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Prediction Of In-Plane Stiffnesses And Thermomechanical Stresses In Cylindrical Composite Cross-Sections, Bryson M. Chan

Master's Theses

Accurate mechanical analysis of composite structures is necessary for the prediction of laminate behavior. Cylindrical composite tubes are a mainstay in many structural applications. The fundamental design of circular composite cross-sections necessitates the development of a comprehensive composite lamination theory. A new analytical method is developed to characterize the behavior of thin-walled composite cylindrical tubes using a modified plate theory. A generated numerical solver can predict properties such as axial stiffness, bending stiffness, layer stresses, and layer strains in composite tubes subjected to combined mechanical loading and thermal effects. The model accounts for the curvature by transforming and translating the …

Associations Between Parenting Stress, Feeding Practices, And Child Eating Behaviors During The Covid-19 Pandemic, Maria G. Gonzalez

Master's Theses

The COVID-19 pandemic provides an important opportunity to understand how parenting stress during social crisis may predict child feeding practices and perceptions of child mealtime behaviors. The objective of the present study was to explore whether parents’ perceived increases in and overall levels of parenting stress during the pandemic were associated with controlling feeding practices and perceptions of child eating behaviors. Parents (n = 284) of 4–6-year-old children completed a cross-sectional online survey between March and April 2020. The survey assessed parents’ perceived change in parenting stress during the onset of the pandemic and levels of parenting stress during …

Stress Ecology Of The Pacific Rattlesnakes (Crotalus Oreganus And Crotalus Helleri), Natalie Claunch

Master's Theses

Stress is a physiological state induced by disturbance or adverse environmental conditions and is modulated by the glucocorticoid hormone corticosterone (CORT) in reptiles. Stressors can have various impacts on vertebrate trait expression and may affect survival or reproduction. Little is known about the effects of chronically elevated CORT in free-ranging reptiles, or the effect of disturbance stress on venom composition in captive snakes.

In chapter 1, we investigated the effects of researcher induced disturbance on CORT levels and venom composition in a group of captive Northern Pacific rattlesnakes (Crotalus oreganus). Venom protein concentration and plasma CORT levels were …

A Finite Element Analysis Of Tibial Stem Geometry For Total Knee Replacements, Aaron Isidro Bautista

Master's Theses

The purpose of this study was to investigate the influence of tibial stem geometry on stress shielding of the tibia for patients with a total knee replacement. Finite element analysis was used to study different tibial stem geometry types, as well as a vast array of different geometric sizes. Both a peg and stem type geometry were analyzed and compared in order to determine what type geometry causes the least amount of stress shielding. A static loading condition with a dynamic loading factor of three was used for the system and the stress responses were analyzed at regions of interest …

Transient Small Wind Turbine Tower Structural Analysis With Coupled Rotor Dynamic Interaction, George R. Katsanis

Master's Theses

Structural dynamics is at the center of wind turbine tower design - excessive vibrations can be caused by a wide range of environmental and mechanical sources and can lead to reduced component life due to fatigue, noise, and impaired public perception of system integrity. Furthermore, periodic turbulent wind conditions can cause system resonance resulting in significantly increased structural loads. Structural vibration issues may become exacerbated in small wind applications where the analytical and experimental resources for system verification and optimization are scarce. This study combines several structural analysis techniques and packages them into a novel and integrated form that can …

House Finches, Carpodacus Mexicanus: Hormones, Stress, And Song Control Regions, Katherine Olivia Ganster

Master's Theses

Song production in songbirds is controlled by parts of the brain known as the song control regions (SCRs). During spring, gonads increase in size, males sing to attract mates, and SCRs become larger. This neuroplasticity is controlled by the change in day length and increased plasma testosterone (T) levels. Plasma T can be reduced by stress through the production of corticosterone (CORT), through the production of beta-endorphin, or through direct effects on the testes via the nervous system. We determined the T, estradiol, and CORT hormonal profiles of wild House Finches by capturing and sampling blood from the finches every …

The Proteomic Response Of Sea Squirts (Genus Ciona Congeners) To Hyposalinity Stress, James S. Koman

Master's Theses

The ascidian species Ciona savignyi and C. intestinalis are invasive species but show interspecific differences in their population response to hypo-saline stress associated with heavy winter-run off events that are predicted to become more frequent due to climate change. Despite an almost world-wide distribution, C. intestinalis seems to be more susceptible to hypo-saline stress than the geographically more limited C. savignyi. Given that the genomes of both species are fully sequenced, we were able to compare their proteomic response to both acute and chronic salinity to characterize the mechanisms that are responsible for setting tolerance limits to hyposaline conditions …