Auburn University

Safety In the Shop: A Theory of Planned Behavior Analysis of Student Perceptions of Safety and First Aid in a Shop Class

2026-01-12T00:00:00Z

Safety In the Shop: A Theory of Planned Behavior Analysis of Student Perceptions of Safety and First Aid in a Shop Class Fogal, James Safety practices in agriculture-based shop classes, especially involving the need for first aid, is of upmost importance. The research in this paper analyzes safety consciousness in agricultural mechanics shop class, specifically related to the knowledge and confidence in performing first aid and CPR skills. This dissertation reviews the importance of safety in agriculture and agriculture-based shop classes and the role that first aid, wilderness advanced first aid, and CPR play within agricultural safety programs. It shows the critical importance for solid first aid and CPR education for the training of agricultural professionals and recommends the teaching of a Wilderness Advanced First Aid class as a part of safety for all working within the field of agriculture.

Compressible Biglobal Stability of Rocket Internal Flowfields

2026-01-07T00:00:00Z

Compressible Biglobal Stability of Rocket Internal Flowfields Ramesh Kumar, Tharikaa Combustion instability remains one of the most persistent challenges in rocket propulsion, where the nonlinear interaction between hydrodynamic structures and acoustic resonances can precipitate severe performance degradation or structural failure. To address this problem, a fully compressible biglobal stability framework is developed to predict hydrodynamic and vorticoacoustic instabilities in both porous solid-rocket-motor chambers and bidirectional vortex engines. Unlike traditional methods that rely on separate modal decomposition, the present formulation preserves compressibility so that acoustic and vortical branches emerge naturally. In the quiescent limit, the solver reproduces the classical Helmholtz eigenfrequencies and mode shapes, thereby confirming the embedded wave dynamics within the compressible Navier–Stokes system. Applied to the compressible Taylor–Culick mean flow, the solver yields a comprehensive eigenspectrum that captures hydrodynamic and vorticoacoustic responses while differentiating between longitudinal, radial, and mixed-frequency structures across tangential orders. Increasing the Mach number produces a systematic detuning of vorticoacoustic frequencies, quantifying the convective influence on modal selection. The analysis further demonstrates how wall injection and flow turning regulate the penetration of acoustic vorticity into the core, shaping the growth rates and topology of the unstable modes. The same framework is extended to the bidirectional vortex engine, representing a class of strongly swirling, injection-driven configurations relevant to liquid and hybrid propulsion. Through the use of complex-lamellar mean flow, the solver captures coupled axial–radial oscillations and delineates stability trends. Collectively, these results provide a unified physics-based foundation for predicting and interpreting modal behavior in compressible rocket flows, thereby advancing the understanding of combustion instability and informing strategies for mitigating flow–acoustic coupling in next-generation propulsion systems.

On Viscous and Compressible Cyclonic Motions in Confined Hemispherical Chambers

2026-01-06T00:00:00Z

On Viscous and Compressible Cyclonic Motions in Confined Hemispherical Chambers Little, Daniel This dissertation presents a theoretical investigation into the mechanics of steady-state, swirl-driven flows confined within an impermeable hemispherical chamber. A hierarchy of three distinct analytical models is developed to systematically isolate and characterize the roles of geometric confinement, weak compressibility, and viscosity. First, a generalized incompressible, inviscid baseline model is derived from the Bragg--Hawthorne equation (BHE). An eigenfunction expansion technique yields a discrete spectrum of solution modes, and the analysis characterizes the evolution of the meridional streamline topology with increasing radial and polar mode numbers. Second, the inviscid framework is extended to incorporate first-order compressibility effects using a Rayleigh--Janzen expansion in the squared injection Mach number. This analysis yields closed-form expressions for the dilatational shifts of several flowfield features, including the mantle surface where the axial velocity reverses; this study also identifies a composite parameter that captures the effects of compressibility. Third, viscous phenomena near solid boundaries are resolved using a multiple-scales asymptotic framework, providing a model for the boundary-layer structure. Collectively, these theoretical results provide a more complete physical understanding of hemispherical vortex flows and establish a set of exact solutions for the verification of computational methods.

Judging a book by its cover: Evaluating the relationship between sexual signals and fitness in an iteroparous species

2026-01-06T00:00:00Z

Judging a book by its cover: Evaluating the relationship between sexual signals and fitness in an iteroparous species Gomes Goethlich, Monet With this dissertation, we evaluated the relationship between sexually selected traits and reproductive success, considering alternative perspectives by which we quantify, evaluate, and interpret these traits. Sexually selected traits, such as cranial appendages in ungulates, can serve as indicators of condition, and researchers often discuss them interchangeably when comparing their role in obtaining greater reproductive success. We discussed the evolution and physiological constraints associated with the development of antlers and horns and propose that permanent versus temporary traits likely communicate vastly different messages in long-lived species. We investigated age-related patterns in antler allometry utilizing 16 years of data from a population of known-aged, freely breeding white-tailed deer (Odocoileus virginianus). We observed a positive, nonlinear relationship between antler and body size across all age classes, where for every for every 10% increase in body size, we observed an 8.05% increase in antler size (± 0.017 SE, P < 0.001). For ages 1.5-5.5 years, antler allometry value had no significant relationship with increased annual reproductive success (P = 0.33-0.79). However, for deer aged 6.5+ years, allometry value was positively associated with annual reproductive success (P = 0.002). We also identified antler characteristics that may facilitate either armament or ornament utility and assessed their relationship to annual reproductive success (ARS). We found sum of antler tine lengths (armament and ornament characteristic) and number of antler points (armament characteristic) to be associated with ARS within our top antler characteristic models, and that gross antler score better predicted this relationship than either variable alone. The relationship between sum of the antler tine lengths, number of antler points, gross antler score and ARS varied quadratically with age, peaking at approximately 5.5 years of age. Additionally, the relationship between number of antler points and ARS declined as the male population age increased (-0.06 ± 0.02, p = 0.007). Despite temptation to identify antlers as either armaments or ornaments, our findings suggest a complex relationship between antler characteristics and ARS, contingent upon age and population dynamics.