Cardiovascular disease is the leading cause of death in firefighters (FF) around the nation. Recent observational studies have emerged suggesting that FF consume calorically dense foods, high in sugar and fat, but low in nutritional value which can exacerbate heart diseases and impair performance. The potential to improve cardiometabolic and performance measurements when following a carbohydrate (CHO) restricted diet (CRD) has gained interest in the literature. To date, only one study has employed a nutrition intervention in FF, yet its’ focus was on nutrient dense foods and antioxidant supplements. Therefore, the purpose of this study was to examine the cardiometabolic and performance effects of a 28-day CRD in FF. 15 career FF participated and finished the present study. Participants reported to the laboratory on 9 separate occasions. Trial 1 consisted of participants having a blood draw performed for assessment of their heart disease risk followed by body composition, blood pressure, and a glucose challenge test (GCT) to assess glucose impairment following ingestion of a 75 g glucose beverage. Trial 2 consisted of a graded exercise cycling test with 5 stages followed by a maximal Wingate for 30 s. Finally, the last trial included the FF physical performance assessment (FPPA) which consisted of a 2.41-km run followed by 2 min of maximal pull-ups, push-ups, and sit-ups. The first 3 trials were used as familiarizations, the second 3 trials were used as baseline measurements, and the last 3 trials followed the 28-day CRD. The CRD consisted of ad-libitum consumption of fat and protein and keeping CHO < 25% daily kilocalorie intake. Dependent variables measured pre- and post-diet included body composition, lipid profile, insulin, cortisol, c-reactive protein (CRP), GCT, substrate oxidation rates, Wingate variables, and the FPPA. Following the diet, participants had significant reductions in CRP, blood pressure, 2.41-km run time, CHO oxidation rates, and fat mass. Participants also had significant increases in high density cholesterol count, fat oxidation rates, and pull-up repetitions. Overall, our results show that a CRD in a high-stress occupation can favorably change markers of heart disease and body composition without decrements to physical performance.

The United States Air Force is in the process of developing a more electric aircraft. The development of an aircraft Integrated Power Unit and an Internal Starter/Generator will be instrumental in producing sufficient electrical power to run all non propulsive systems. Iron-cobalt alloys, such as Hiperco&#61650; alloy 50HS, are high temperature, high strength magnetic materials ideal for these power applications. Design requirements and previous studies indicate that these materials need to survive in temperatures up to 1000&#61616;F (810K), rotation speeds of about 55,000 rpm, and have strengths in excess of 80 ksi. Research conducted by Fingers provided the material and creep properties used in the analysis presented in this report. The finite element method was used to analyze a spinning rotor mounted to a circular shaft via an interference fit subjected to various operating environments. The power law creep model defined by Fingers was used to analyze three distinct rotor configurations. The first configuration was a constant temperature single lamina, mounted to a shaft of equal thickness, subject to temperatures between 727K and 780K, rotation speeds between 35,000 rpm and 60,000 rpm, and two different interference fits: 0.0015 inches and 0.003 inches. The results yield conservative predictions that indicate that these models could not survive the required operating conditions. The second configuration was a linear radial variation in temperature single lamina, mounted to a shaft of equal thickness, subjected to three temperature ranges, rotation speeds between 30,000 rpm and 55,000 rpm, and two different interference fits; 0.0015 inches and 0.003 inches. These results represent a more realistic model, which indicate that the "cooler" inner portions of the rotor restrict the creep deformations of the "hotter" outer portions resulting in higher possible operating temperatures and rotation speeds very near the required operating conditions. The third configuration was a lamina stack comprised of two rotor lamina, with a Coulomb friction surface interaction, and held together by a compressive axial force. These models represent a first step towards understanding the behavior of the entire rotor stack. / Master of Science

The present study had four main objectives. First, the relationship between the provision of spousal support and its theoretical antecedents and consequences was assessed as informed by the conservation of resources theory (Hobfoll, 1989). Second, the crossover of physicians' work interference with family conflict on their spouses' family demands (perceived family demands and family hours) was investigated. Next, the mediating role of social support as an explanation for the crossover process was examined using two distinct pathways. Lastly, the fourth objective of the present study was to investigate the relationships described above across multiple time points and using dual-source data (from physicians and their spouses). The final sample included matched responses from 126 couples across two time points. Results were generally supportive of the relationship between the provision of spousal support and the receipt of spousal support, perceived family demands, family hours, and work interference with family conflict (WIF) and were consistent with expected relationships according to COR theory. Results also provided support for the synchronous crossover of WIF on perceived family demands; however, results were generally unsupportive of the mediating role of the provision of spousal support in the crossover process. The present study makes several important contributions to the social support, work-family conflict, and crossover literatures by adding to the knowledge of the antecedents and consequences of the provision of spousal support, the growing body of research examining the crossover of WIF, and the understanding of the mediating role of the provision of spousal support in the crossover process. Major findings and areas of opportunity for future research are discussed.

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