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Patients with severe heart failure (HF) are often excluded from exercise training studies due to their potentially unstable nature and severe exercise intolerance. Steady state cycling and walking have been the most common interventions and it is unknown whether these training modalities are appropriate and safe for patients with severe HF as they can produce significant cardiovascular stress. Body-weight supported treadmill (BWST) training may be beneficial in patients with severe HF by improving the periphery while minimizing cardiac loading. The purpose of this study was to: 1) assess the safety and feasibility of BWST training in severe HF patients and 2) to evaluate the effect of BWST training on functional capacity, health-related quality of life (HRQL ), cardiopulmonary function, and blood vessel function. Three male patients with severe HF participated in the study. On study entry and at the end of 24 sessions of physician supervised BWST training, patients completed a cardiopulmonary exercise test, two HRQL questionnaires, a 6-Minute Walk Test (6-MWT), and a Doppler ultrasound study. Although there were no study-related adverse events, only one subject (Patient 1) was able to complete post-testing. However, all three patients seemed to demonstrate a general trend towards increased exercise tolerance. By the seventeenth exercise session, the BWS was reduced to zero for Patient 1. In addition, Patient 1 achieved an average walking speed of2.0 km/hr and was completing 34 minutes ofwalking with minimal rest periods by the end of the training program. Patients 2 and 3 also responded to the training as evidenced by a slight increase in exercise duration. However due to fluctuations in their health status, they did not have any substantial improvement. Patient 1 experienced substantial increases in functional capacity: a 64% increase in V02 peak (7.2 to 11.7 ml/kg/min); a 33% increase in peak power output (300 to 400 kpm/min); a 37% increase in VE peak (28 to 39 L/min); and a 28% increase in 6-MWT distance (223. 5 to 286m). In addition, Patient 1 's NYHA-FC improved after training from class III to II. A significant training effect was also evident by reductions in HR at rest (96 to 79 bpm) and during submaximal exercise (100 kpm/min) (105 to 84 bpm). HRQL also tended to improve for Patient 1. Based on these findings and observations, two conclusions can be made. First, patients with severe HF can safely participate in BWST training and may derive considerable benefits. Second, the feasibility of training patients with severe HF is highly dependent on their cardiac condition and other co-morbidities remaining stable enough to allow consistent training. / Thesis / Master of Science (MS)

Metal additive manufacturing stands poised to disrupt multiple industries with high material use efficiency and complex part production capabilities, however many technologies deposit material with sub-optimal properties, limiting their use. This decrease in performance largely stems from porosity laden parts, and asymmetric solidification-based microstructures. Solid-state additive manufacturing techniques bypass these flaws, using deformation and diffusion phenomena to bond material together layer by layer. Among these techniques, Additive Friction Stir Deposition (AFSD), stands out as unique for its freeform nature, and thermomechanical conditions during material processing. Leveraging its solid-state behavior, optimized microstructures produced by AFSD can reach performance levels near, at, or even above traditionally prepared metals. A strong understanding of the material conditions during AFSD and the phenomena responsible for microstructure evolution. Here we discuss two works aimed at improving the state of knowledge surrounding AFSD, promoting future microstructure optimization. First, a parametric study is performed, finding a wide array of producible microstructures across two material systems. In the second work, a stop-action type experiment is employed to observe the dynamic microstructure evolution across the AFSD material flow pathway, finding specific thermomechanical regimes that occur within. Finally, multiple conventional alloy systems are discussed as their microstructure evolution pertains to AFSD, as well as some more unique systems previously limited to small lab scale techniques, but now producible in bulk due to the additive nature of AFSD. / Doctor of Philosophy / The microstructure of a material describes the atomic behavior at multiple length scales. In metals this microstructure generally revolves around the behavior of millions of individual crystals of metal combined to form the bulk material. The state and behavior of these crystals and the atoms that make them up influence the strength and usability of the material and can be observed using various high fidelity characterization techniques. In metal additive manufacturing (i.e. 3D printing) the microstructure experiences rapid and severe changes which can alter the final properties of the material, typical to a detrimental effect. Given the other benefits of additive manufacturing such as reduced costs and complex part creation, there is desire to predict and control the microstructure evolution to maximize the usability of printed material. Here, the microstructure evolution in a solid-state metal additive manufacturing, Additive Friction Stir Deposition (AFSD), is investigated for different metal material systems. The solid-state nature of AFSD means no melting of the metal occurs during processing, with deformation forcing material together layer by layer. The conditions experienced by the material during printing are in a thermomechanical regime, with both heating and deformation applied, akin to common blacksmithing. In this work specific microstructure evolution phenomena are discussed for multiple materials, highlighting how AFSD processing can be adjusted to change the resulting microstructure and properties. Additionally, specific AFSD process interactions are studied and described to provide better insight into cumulative microstructure evolution throughout the process. This work provides the groundwork for investigating microstructure evolution in AFSD, as well as evidence and results for a number of popular metal systems.

Severe weather events frequently affect important marine fish stocks and fisheries along the United States Atlantic and Gulf of Mexico coasts. However, the effects of these events on fish and fisheries are not well understood. The availability of self-reported data from two fisheries in a region frequently affected by tropical cyclones provided a unique opportunity to investigate short-term responses to past events. This study involved selecting severe weather events, calculating changes in effort and catch-per-unit- effort (CPUE), and analyzing those changes across various temporal, spatial, and species-specific scenarios. Responses in each variable were analyzed within and across scenario factors and explored for correlations and linear multivariate relationships with hypothesized explanatory variables. A negative overall directional change was identified for logbook fishing effort. Based on both correlations and linear models, changes in logbook fishing effort were inversely related to changes in average maximum wind speed. Severe weather events are more likely to affect fishing effort than catch rates of reef-fish species. However, lack of responses in CPUE may also relate to the ability of this study to detect changes. The temporal and spatial scales analyzed in this study may not have been adequate for identifying changes in effort for the headboat fishery, or in CPUE for either fishery. Although there was no region-wide response in CPUE associated with severe weather events, further research on this topic is necessary to determine if storm-induced changes in fishery data are likely strong, long-lasting, or widespread enough to influence the outcome of stock-wide assessments. / Master of Science

Las secuencias de accidente con rotura de tubos en el generador de vapor (secuencias SGTR) están consideradas como contribuyentes del riesgo en reactores de agua a presión. Su relevancia radica en la potencial liberación de aerosoles radioactivos al medio ambiente en caso de accidente severo. Sin embargo, dichas partículas podrían quedar retenidas parcial o totalmente sobre las superficies del generador de vapor, incluso en condiciones extremas de ausencia de agua en el generador de vapor. La carencia de conocimiento en cuanto a la capacidad de retención de término fuente de este componente ha eludido su consideración en los estudios probabilistas de seguridad y en las guías de gestión de accidente severo. Esta tesis es una contribución a la comprensión y cuantificación de los procesos naturales de mitigación que tienen lugar dentro del generador de vapor como consecuencia de los accidentes SGTR. La principal actividad llevada a cabo ha sido el desarrollo de un modelo teórico que calcula la capacidad de retención de aerosoles en la etapa de rotura de un generador de vapor seco. El modelo, llamado ARI3SG, está basado en una aproximación de filtro y tiene una naturaleza semi-empírica. En él se tienen en cuenta tanto la dinámica de aerosoles como la hidrodinámica de aerosoles que tiene lugar dentro del generador de vapor en este tipo de escenarios. Para esto último, se han llevado a cabo una serie de simulaciones con el código tridimensional FLUENT 6.2, que han sido validadas con datos experimentales. El comportamiento del modelo ha sido evaluado en profundidad: primero, a través de un proceso de verificación con el que se ha visto que es robusto. Segundo, a través de un proceso de validación frente a los datos experimentales disponibles. Tercero, a través del estudio del efecto de las incertidumbres del escenario y del modelo sobre los resultados. La comparación frente a los datos experimentales ha sido satisfactoria y muestra la viabilidad del uso de formulaciones como la de ARI3SG en códigos de sistema. / López Del Prá, C. (2012). A THEORETICAL INVESTIGATION OF AEROSOL RETENTION WITHIN THE SECONDARY SIDE OF A STEAM GENERATOR UNDER A SGTR SEVERE ACCIDENT SEQUENCE IN A PWR NUCLEAR POWER PLANT [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/15183

Recent severe weather research has examined the potential role of total lightning patterns in the severe thunderstorm warning-decision process although none to-date have examined these patterns in explicitly weak-shear environments. Total lightning flashes detected by the Earth Networks Total Lightning Network (ENTLN) during the 2012-13 convective seasons (1 May – 31 August) over a region of the Central Appalachian Mountains were clustered into likely discrete thunderstorms and subsequently classified as either single-cell or multicell/supercell storm modes. The classification of storms was determined using a storm index (SI) which was informed by current National Weather Service (NWS) identification techniques. The 36 days meeting the minimum threshold of lightning activity were divided into 24 lightning-defined (LD) single-cell thunderstorm days and 12 LD multicell/supercell days. LD single-cell days possessed statistically significant lower 0000 UTC 0-6 km wind shear (13.8 knots) than LD multicell/supercell days (26.5 knots) consistent with traditional expectations of single-cell and multicell/supercell environments respectively. The popular 2σ total lightning jump algorithm was applied to all flashes associated with 470 individual LD thunderstorms. The frequencies of the storms’ total lightning jumps were then compared against any associated severe weather reports as an accuracy assessment. The overall performance of the algorithm among both categories was much poorer than in previous studies. While probability of detections (POD) of the 2σ algorithm were comparable to previous research, false alarm rates (FAR) were much greater than previously documented. Given these results, the 2σ algorithm does not appear fit for operational use in a weak shear environment. / Master of Science