Environmental challenges, such as global warming, growing demand on energy, and diminishing oil sources have accelerated research on alternative energy conversion methods. Thermoelectric power generation is a promising method to convert wasted heat energy into useful electrical energy form. A temperature gradient imposed on a thermoelectric device produces a Seebeck potential. However, this temperature gradient causes thermal stresses due to differential thermal expansions and mismatching of the bonded components of the device. Thermal stresses are critical for thermoelectric devices since they can generate failures, including dislocations, cracks, fatigue fractures, and even breakdown of the entire device. Decreases in power-generation performance and operation lifetime are major consequences of these failures. In order to minimize thermal stresses in the legs without affecting power-generation capabilities, this study concentrates on structural solutions. Thermoelectric devices with non-segmented and segmented legs were modeled. Specifically, the possible effect of various leg geometries, configurations, and dimensions were evaluated using finite-element and statistical methods. Significant changes in the magnitudes and distributions of thermal stresses occurred. Specifically, the maximum equivalent stresses in the rectangular-prism and cylindrical legs were 49.9 MPa and 43.3 MPa, respectively for the temperature gradient of 100ºC. By using cylindrical legs with modified dimensions, decreases in the maximum stresses in legs reached 21.2% without affecting power-generation performance. Moreover, the effect of leg dimensions and coaxial-leg configurations on power generation was significant; in contrast, various leg geometries and rotated-leg configurations had very limited affect. In particular, it was possible to increase power output from 20 mW to 65 mW by simply modifying leg widths and heights within the defined range. It should be noted, however, this modification also increased stress levels. It is concluded that leg geometries, configurations, and dimensions can be redesigned for improved durability and overall performance of thermoelectric devices.

"Spray cooling has been important to control die temperature in forging processes for years. One area that has had little research is how thermal stresses in a metal are related to flow characteristics of the spray. Wyman-Gordon Corporation at its North Grafton MA facility uses spray cooling to cool their die after a forging process. The current system used is found to cause cracking along the surface of the impression in the die. The purpose of this project is to compare the nozzle system used by Wyman-Gordon to selected commercially available spray nozzles, and determine if there is a better spray cooling system than the one currently used. First the flow parameters, of Sauter mean diameter, particle velocity, and volumetric spray flux were experimentally found using a laser PDA system for four water driven nozzles, including the Wyman-Gordon nozzle, and one air-atomizing nozzle. The water atomizing nozzles were tested using pressures from 30 psi to 150 psi. For the air-atomizing nozzle, the water pressure was set at 60 psi and the air pressure was varied from 30 to 150 psi. Three nozzles were chosen, the Wyman-Gordon nozzle, the smaller orifice water atomizing nozzle, the air-atomizing nozzle, and an air stream, to conduct an inverse heat conduction experiment. Using the temperature gradients created by the cooling effects of each nozzle, the heat flux and induced thermal stresses were determined. The results showed the Wyman-Gordon nozzle was causing higher thermal stresses than the air/water and water nozzles. However, the air-atomizing nozzle and air stream, due to the high temperatures that the dies are subjected to, did not cool the die quick enough to be practical. The smaller orifice water atomizing nozzle proved to be the nozzle that would cool the surface of the dies within a practical time, and induce allowable thermal stresses, sufficiently enough below the yield strength of the die material. These results, although collected specifically to study the cooling of dies at Wyman-Gordon, could be generalized to include the cooling of any test piece with a high surface temperature. "

Este trabalho teve como objetivo avaliar um programa de suplementação de luz no desenvolvimento, desempenho e comportamento de bezerros em aleitamento e o uso da câmera termográfica como método para avaliação de variáveis fisiológicas por método não invasivo. O experimento foi realizado na Agência Paulista de Tecnologia dos Agronegócios - APTA, em Ribeirão Preto, SP. Foram utilizados 20 bezerros Jersey e mestiços da raça, divididos em dois tratamentos, com e sem programa de suplementação de luz artificial. O programa de suplementação de luz artificial consistiu em 6 h de luz artificial (das 00:00 as 6:00 h), completando 18 horas de luz por dia. Foram avaliadas as características fisiológicas dos animais: frequência respiratória (FR), temperatura da superfície do pelame (TSP), temperatura auricular (TA), temperatura caudal (TC) e temperatura retal (TR). A ingestão de ração e água também foi estudada. Avaliou-se também o desenvolvimento dos animais através dos ganhos médios diários de peso (GPMD), de altura, de comprimento e de perímetro torácico (PT). Foi estudado o comportamento social e ingestivo dos animais. E por fim, através de cinco coletas de dados em dias de alta entalpia, onde os dados foram registrados em quatro horários (18:00, 00:00, 06:00 e 12:00 h). Foram registradas as seguintes variáveis fisiológicas: TSP e TC, TA, e TR (método convencional). As fotos termográficas foram registradas com uma câmera termográfica, nos mesmos dias e horários de registros das variáveis fisiológicas pelo método convencional. As variáveis fisiológicas não apresentaram diferença significativa entre os tratamentos (P>0,0001), porém apresentaram diferença entre os horários de coleta, sendo que as maiores temperaturas foram encontradas na coleta das 12 h. O consumo de água e ração no experimento não teve variação significativa (P>0.01). Nos dias de alta entalpia a ingestão de água variou somente para o período de 31 a 75 dias de idade dos animais. O desenvolvimento dos animais mostrou diferença quando foram submetidos ao programa de suplementação de luz. O GPMD e o PT dos animais foi maior (P<0,001) para o tratamento sem luz, a altura foi influenciada (P=0,008) pela idade dos animais e o comprimento variou de acordo com o tratamento (P=0,006) e a idade (P=0,001). O programa de suplementação de luz não mostra diferenças nas variáveis fisiológicas e no consumo de alimento de bezerros em aleitamento, e o desenvolvimento dos animais é prejudicado nesta fase. O comportamento social dos animais não sofreu efeito significativo (P>0,05) do tratamento de luz, porém os períodos do dia dividido de seis em seis horas, influenciou a comportamento dos animais. As atividades de ócio e dormindo são as mais frequentes na criação de bezerros em aleitamento. O comportamento ingestivo é alterado pela presença de luz e pelo período do dia, sendo que os animais mostram maior consumo de água e ração quando não são submetidos a luz artificial. Os valores obtidos pelos dois métodos de colheita de dados foram correlacionados. Contudo, é possível relacionar fotos termográficas de bezerros em aleitamento com o método convencional de registro de temperaturas corporais. Para este trabalho, utilizou-se a temperatura auricular, na qual foi apresentada uma regressão para obter as demais temperaturas corporais do animal. / This study aimed to evaluate a light supplementation program on the development, performance and behavior of suckling calves and the use of thermographic camera as an evaluation method of physiological variables by a non-invasive method. The experiment was conducted in Sao Paulo Agency of Agribusiness Technology - APTA, in Ribeirao Preto, SP, Brazil. Were used 20 Jersey and crossbred calves, divided in two treatments, with and without artificial light supplementation. The light supplementation program consisted on 6 hours of artificial light (from 00:00 to 6:00 h), completing 18 hours of light per day. Were evaluated the physiological characteristics of the animals: respiratory frequency (RF), coat surface temperature (CST), ear temperature (ET), tail temperature (TT) e rectal temperature (RT). The ingestion of food and water was also considered. Was also evaluated the development of the animals through the daily average weight gain (BG), height, length and thoracic girth (TG). It was also evaluated the social and ingestive behavior of the animals. The experiment consisted of collecting data on five days of high enthalpy, where the data were recorded at four times (18, 00, 06 and 12 hours). It recorded the following physiological variables: coat surface temperature (CST) and flow temperature (FT) with infrared thermometer, ear temperature (ET) with digital ear thermometer, and rectal temperature (RT) with digital thermometer (conventional method). The thermography images were recorded with a thermography camera, on the same days and hours of record of physiological variables by the conventional method. Physiological variables showed no signicant difference between treatments (P>0,0001), but differ between the collection times, and the highest temperatures were found in the collection of 12 h. The water and food intake in the experimente did not change significantly (P>0.01). In the days of high water intake varied only for the period from 31 to 75 days old animals. The development of the animals showed a difference when they were submitted to the program of supplemental ligth. The ABW and TG of the animals was higher (P<0,001) for the treatment without light, and was also influenced (P=0,008)bye the age and length of the animals varied according to treatment (P=0,006) and age (P=0,001). The programo f supplementary light shows no diferences in physiological parameters, feed intake of suckling calves, and development of animals is impaired at this stage. The social behavior of animals was not affected (P>0,05) of the light treatment but the periods of the divided every six hours, influenced the behavior of animals. The leisure and sleeping activities are the most frequente in the creation of suckling calves. Feeding behavior is altered by the presence of light and time of day, and the animals show higher consumption of water and food when they are not subjected to artificial light. The values obtained by two methods of data collection were correlated. It is possible to relate thermography pictures of suckling calves on the conventional method if recording body temperatures. For this work we use the ear temperature, which was presented in a regression to obtain the rest of the animal body temperatures.

Made available in DSpace on 2017-07-10T19:25:11Z (GMT). No. of bitstreams: 1 sara.pdf: 194808 bytes, checksum: 22cd048e43a252ebba8d4a765f19839e (MD5) Previous issue date: 2012-06-14 / The common bean has great nutritional and economic importance in Brazil. It has high protein content, being a balanced food, rich in iron, calcium, vitamins, carbohydrates, fiber and lysine, representing the basis of Brazilian food. From a physiological point, it can be considered a culture with high requirement on climate conditions, and it is considered highly sensitive to frost, since it already suffers damage from temperatures lower than 4 °C. In this study, it was evaluated the technological quality of the beans, subjected to thermal stress by cold after physiological maturity, during storage environmental conditions for 0, 30, 60 and 90 days. Factors such as color, moisture content, percentage of soaking, volumetric expansion, percentage of whole grains, tannins, proteins and cooking time were evaluated. Statistical analysis consisted of analysis of variance and Tukey comparison test at 5% significance. No significant differences were found among treatments in soaking, tannins and cooking time. Regarding the color, brightness showed significant differences for time with no difference between treatments. The protein suffered a decrease in time, but there was no influence of frost. It was concluded that thermal stress by cold after physiological maturity did not affect the beans technological quality. / feijão tem grande importância nutricional e econômica no Brasil. Possui alto teor de proteína, sendo um alimento balanceado e rico em ferro, cálcio, vitaminas, carboidratos, fibras e lisina, constituindo base alimentar dos brasileiros. No aspecto fisiológico, pode-se considerar o feijão como cultura das mais exigentes em clima, sendo que o mesmo é considerado altamente sensível à geada, pois já sofre danos a partir de temperaturas menores de 4 ºC. Avaliou-se neste trabalho a qualidade tecnológica do feijão comum, submetido a estresse térmico por frio após a maturidade fisiológica, durante o armazenamento condições ambientais por 0, 30, 60 e 90 dias. Foram avaliadas a cor, teor de água, percentual de embebição, expansão volumétrica, percentual de grãos inteiros, taninos, tempo de cozimento e proteínas. A análise estatística consistiu em análise de variância e teste de comparação de médias Tukey a 5% de significância. Não foram encontradas diferenças significativas entre os tratamentos na embebição, taninos e tempo de cozimento. Em relação à cor, a luminosidade apresentou diferenças significativas para o tempo, não havendo diferença entre os tratamentos. O teor de proteína sofreu decréscimo no tempo; porém, não houve influência da geada. Concluiu-se que o estresse térmico por frio após a maturidade fisiológica não afetou a qualidade tecnológica dos grãos de feijão.

Este trabalho teve como objetivo avaliar um programa de suplementação de luz no desenvolvimento, desempenho e comportamento de bezerros em aleitamento e o uso da câmera termográfica como método para avaliação de variáveis fisiológicas por método não invasivo. O experimento foi realizado na Agência Paulista de Tecnologia dos Agronegócios - APTA, em Ribeirão Preto, SP. Foram utilizados 20 bezerros Jersey e mestiços da raça, divididos em dois tratamentos, com e sem programa de suplementação de luz artificial. O programa de suplementação de luz artificial consistiu em 6 h de luz artificial (das 00:00 as 6:00 h), completando 18 horas de luz por dia. Foram avaliadas as características fisiológicas dos animais: frequência respiratória (FR), temperatura da superfície do pelame (TSP), temperatura auricular (TA), temperatura caudal (TC) e temperatura retal (TR). A ingestão de ração e água também foi estudada. Avaliou-se também o desenvolvimento dos animais através dos ganhos médios diários de peso (GPMD), de altura, de comprimento e de perímetro torácico (PT). Foi estudado o comportamento social e ingestivo dos animais. E por fim, através de cinco coletas de dados em dias de alta entalpia, onde os dados foram registrados em quatro horários (18:00, 00:00, 06:00 e 12:00 h). Foram registradas as seguintes variáveis fisiológicas: TSP e TC, TA, e TR (método convencional). As fotos termográficas foram registradas com uma câmera termográfica, nos mesmos dias e horários de registros das variáveis fisiológicas pelo método convencional. As variáveis fisiológicas não apresentaram diferença significativa entre os tratamentos (P>0,0001), porém apresentaram diferença entre os horários de coleta, sendo que as maiores temperaturas foram encontradas na coleta das 12 h. O consumo de água e ração no experimento não teve variação significativa (P>0.01). Nos dias de alta entalpia a ingestão de água variou somente para o período de 31 a 75 dias de idade dos animais. O desenvolvimento dos animais mostrou diferença quando foram submetidos ao programa de suplementação de luz. O GPMD e o PT dos animais foi maior (P<0,001) para o tratamento sem luz, a altura foi influenciada (P=0,008) pela idade dos animais e o comprimento variou de acordo com o tratamento (P=0,006) e a idade (P=0,001). O programa de suplementação de luz não mostra diferenças nas variáveis fisiológicas e no consumo de alimento de bezerros em aleitamento, e o desenvolvimento dos animais é prejudicado nesta fase. O comportamento social dos animais não sofreu efeito significativo (P>0,05) do tratamento de luz, porém os períodos do dia dividido de seis em seis horas, influenciou a comportamento dos animais. As atividades de ócio e dormindo são as mais frequentes na criação de bezerros em aleitamento. O comportamento ingestivo é alterado pela presença de luz e pelo período do dia, sendo que os animais mostram maior consumo de água e ração quando não são submetidos a luz artificial. Os valores obtidos pelos dois métodos de colheita de dados foram correlacionados. Contudo, é possível relacionar fotos termográficas de bezerros em aleitamento com o método convencional de registro de temperaturas corporais. Para este trabalho, utilizou-se a temperatura auricular, na qual foi apresentada uma regressão para obter as demais temperaturas corporais do animal. / This study aimed to evaluate a light supplementation program on the development, performance and behavior of suckling calves and the use of thermographic camera as an evaluation method of physiological variables by a non-invasive method. The experiment was conducted in Sao Paulo Agency of Agribusiness Technology - APTA, in Ribeirao Preto, SP, Brazil. Were used 20 Jersey and crossbred calves, divided in two treatments, with and without artificial light supplementation. The light supplementation program consisted on 6 hours of artificial light (from 00:00 to 6:00 h), completing 18 hours of light per day. Were evaluated the physiological characteristics of the animals: respiratory frequency (RF), coat surface temperature (CST), ear temperature (ET), tail temperature (TT) e rectal temperature (RT). The ingestion of food and water was also considered. Was also evaluated the development of the animals through the daily average weight gain (BG), height, length and thoracic girth (TG). It was also evaluated the social and ingestive behavior of the animals. The experiment consisted of collecting data on five days of high enthalpy, where the data were recorded at four times (18, 00, 06 and 12 hours). It recorded the following physiological variables: coat surface temperature (CST) and flow temperature (FT) with infrared thermometer, ear temperature (ET) with digital ear thermometer, and rectal temperature (RT) with digital thermometer (conventional method). The thermography images were recorded with a thermography camera, on the same days and hours of record of physiological variables by the conventional method. Physiological variables showed no signicant difference between treatments (P>0,0001), but differ between the collection times, and the highest temperatures were found in the collection of 12 h. The water and food intake in the experimente did not change significantly (P>0.01). In the days of high water intake varied only for the period from 31 to 75 days old animals. The development of the animals showed a difference when they were submitted to the program of supplemental ligth. The ABW and TG of the animals was higher (P<0,001) for the treatment without light, and was also influenced (P=0,008)bye the age and length of the animals varied according to treatment (P=0,006) and age (P=0,001). The programo f supplementary light shows no diferences in physiological parameters, feed intake of suckling calves, and development of animals is impaired at this stage. The social behavior of animals was not affected (P>0,05) of the light treatment but the periods of the divided every six hours, influenced the behavior of animals. The leisure and sleeping activities are the most frequente in the creation of suckling calves. Feeding behavior is altered by the presence of light and time of day, and the animals show higher consumption of water and food when they are not subjected to artificial light. The values obtained by two methods of data collection were correlated. It is possible to relate thermography pictures of suckling calves on the conventional method if recording body temperatures. For this work we use the ear temperature, which was presented in a regression to obtain the rest of the animal body temperatures.

Made available in DSpace on 2017-05-12T14:48:35Z (GMT). No. of bitstreams: 1 sara.pdf: 194808 bytes, checksum: 22cd048e43a252ebba8d4a765f19839e (MD5) Previous issue date: 2012-06-14 / The common bean has great nutritional and economic importance in Brazil. It has high protein content, being a balanced food, rich in iron, calcium, vitamins, carbohydrates, fiber and lysine, representing the basis of Brazilian food. From a physiological point, it can be considered a culture with high requirement on climate conditions, and it is considered highly sensitive to frost, since it already suffers damage from temperatures lower than 4 °C. In this study, it was evaluated the technological quality of the beans, subjected to thermal stress by cold after physiological maturity, during storage environmental conditions for 0, 30, 60 and 90 days. Factors such as color, moisture content, percentage of soaking, volumetric expansion, percentage of whole grains, tannins, proteins and cooking time were evaluated. Statistical analysis consisted of analysis of variance and Tukey comparison test at 5% significance. No significant differences were found among treatments in soaking, tannins and cooking time. Regarding the color, brightness showed significant differences for time with no difference between treatments. The protein suffered a decrease in time, but there was no influence of frost. It was concluded that thermal stress by cold after physiological maturity did not affect the beans technological quality. / feijão tem grande importância nutricional e econômica no Brasil. Possui alto teor de proteína, sendo um alimento balanceado e rico em ferro, cálcio, vitaminas, carboidratos, fibras e lisina, constituindo base alimentar dos brasileiros. No aspecto fisiológico, pode-se considerar o feijão como cultura das mais exigentes em clima, sendo que o mesmo é considerado altamente sensível à geada, pois já sofre danos a partir de temperaturas menores de 4 ºC. Avaliou-se neste trabalho a qualidade tecnológica do feijão comum, submetido a estresse térmico por frio após a maturidade fisiológica, durante o armazenamento condições ambientais por 0, 30, 60 e 90 dias. Foram avaliadas a cor, teor de água, percentual de embebição, expansão volumétrica, percentual de grãos inteiros, taninos, tempo de cozimento e proteínas. A análise estatística consistiu em análise de variância e teste de comparação de médias Tukey a 5% de significância. Não foram encontradas diferenças significativas entre os tratamentos na embebição, taninos e tempo de cozimento. Em relação à cor, a luminosidade apresentou diferenças significativas para o tempo, não havendo diferença entre os tratamentos. O teor de proteína sofreu decréscimo no tempo; porém, não houve influência da geada. Concluiu-se que o estresse térmico por frio após a maturidade fisiológica não afetou a qualidade tecnológica dos grãos de feijão.

L'objectif de ce travail de thèse était d'étudier les effets de l'hyperthermie sur la proprioception et leurs répercussions sur la cinématique de la course à pied. Nous avons élaboré un protocole expérimental composé de deux études pour répondre à cette question. La première expérimentation a exploré l'hyperthermie induite en mode passif et son effet sur la proprioception. Notre hypothèse était que les perturbations neuromusculaires induites par une hyperthermie passive générale pourraient affecter la proprioception et l'équilibre. 14 participants ont réalisé une série de tests de la fonction neuromusculaire ainsi que des tests de proprioception et d'équilibre statique et dynamique dans une chambre environnementale en conditions chaude (44°C-50°C) et contrôle (24°C). Les résultats de cette 1ère étude ont montré qu'une augmentation de la température rectale (39.0°C vs. 36.9°C) et cutanée (37.9°C vs. 32°C) en ambiance chaude par rapport à la situation de contrôle était associée à une réduction de l'amplitude du reflexe H, une diminution de l'acuité proprioceptive et des perturbations de l'équilibre statique et dynamique. Ces résultats suggèrent que l'hyperthermie passive détériore la proprioception et l'équilibre, ce qui pourrait affecter le geste sportif. Afin d'explorer les effets de l'hyperthermie active sur la proprioception, nous avons par la suite réalisé le test de proprioception active chez 12 coureurs entrainés avant et après un test de 30 minutes en course à pied dans des conditions chaude (39°C) et contrôle (22°C). Les résultats de cette étude ont montré une augmentation plus importante des contraintes thermiques, perceptives et cardiovasculaires en ambiance chaude comparé à la condition tempérée. En plus, nous avons observé une diminution de l'acuité proprioceptive suite à l'exercice en ambiance chaude mais pas tempérée. Ces résultats montrent que les altérations identifiées en situation d'hyperthermie passive lors de la première étude sont également spécifiques à un exercice en ambiance chaude. Lors de ce protocole expérimental, nous avons également exploré les répercussions de ces perturbations de la proprioception sur la cinématique de la course à pied. Pour ce faire, les paramètres spatio-temporels et cinématiques angulaires de la foulée ont été mesurés à vitesse constante (i.e., 70% de la vitesse maximale aérobie) lors de la première et dernière minute de l'exercice (la vitesse étant librement choisie de la 2ème à la 29ème minute). Nous avons ainsi montré une diminution de la fréquence et une augmentation de la longueur des foulées avec la fatigue dans les deux conditions ; accompagnée de changement des paramètres angulaires limités à un redressement du bassin et une diminution de l'angle de la cheville. Cependant, Il n'y avait aucun effet de la condition thermique ou d'interaction entre la fatigue et l'environnement thermique pour les paramètres spatio-temporels et cinématiques angulaires. Ces résultats suggèrent que l'hyperthermie induite par un exercice de course à pied affecte la proprioception de la cheville, mais que cette altération n'affecte pas la cinématique de la course à pied. Suite à ces travaux, nous pouvons donc conclure que la proprioception est affectée par l'hyperthermie induite soit par des méthodes passives ou actives. Ces altérations pourraient provenir des effets de l'hyperthermie sur les fonctions neuromusculaire et cognitive. Cependant, la dégradation de l'acuité proprioceptive avec une augmentation de la température rectale au-delà de 39°C n'affecte pas la cinématique de la course à pied, ce qui suggère une forte stabilité du pattern de course malgré une proprioception et des fonctions neuromusculaires affectées / The objective of this PhD was to investigate the effects of hyperthermia on proprioception and their impact on running gait kinematics. We developed an experimental protocol consisting of two studies to answer this question.The first experiment explored passive hyperthermia and its effects on proprioception and balance. We hypothesized that neuromuscular disturbances induced by passive hyperthermia would impair proprioception and balance. 14 participants performed a series of tests of neuromuscular function, proprioception, as well as static and dynamic balance in an environmental chamber under hot (44°C - 50°C) and control (24°C) conditions. The results of this first study showed that an increase in rectal (39.0°C vs. 36.9°C) and skin (37.9°C vs. 32°C) temperatures in hot compared to control ambient conditions was associated with a reduction in the amplitude of the Hoffman reflex, a decrease in the proprioceptive acuity and impairments in static and dynamic balance. These results suggest that passive hyperthermia deteriorates proprioception and balance, something that could potentially affect sports movement. ln order to explore the effects of active hyperthermia on proprioception, we subsequently performed the active discrimination test in 12 trained runners before and just after a 30-minute running time-trials under hot (39°C) and control (22°C) conditions. The results of this study showed a larger increase in thermal, perceptual and cardiovascular stresses when running in the heat as compared to running in a temperate environment. ln addition, we observed a decrease in proprioceptive acuity following exercising in the heat only. This showed that the proprioceptive impairments identified during the first study are also present following exercise-induced hyperthermia, but not exercise-induced fatigue without hyperthermia. During this study, we have also explored the impact of hyperthermia-induced alterations in proprioception on running gait kinematics. To do so, we measured angular kinematics and spatiotemporal stride parameters at a constant speed (i.e., 70% of the maximum aerobic speed) during the first and last minute of the exercise (whilst speed was freely chosen from the 2nd to the 29th minute). Results showed that fatigue decreased step frequency and increase step length under both conditions, along inducing a few little changes in the angular kinematic parameters limited to an increase of the PELVlS angle and a decrease of the ANKLE angle. However, no interaction effect was found for any of the spatiotemporal or angular stride parameters. These results suggest that exercise-induced hyperthermia impairs ankle proprioception, but that this alteration does not affect running kinematics. ln summary, proprioception is affected by hyperthermia induced either by passive or active methods. These alterations could be due to the effects of hyperthermia on neuromuscular and cognitive functions. However, the degradation of proprioceptive acuity with an increase in rectal temperature above 39 °C does not affect the kinematics of running, suggesting that running pattern remains stable despite proprioception and neuromuscular functions impairments

To assemble the fulcrum of bascule bridges, a trunnion is immersed into liquid nitrogen so that it can be shrunk fit into the hub. This is followed by immersing the resulting trunnion-hub assembly into liquid nitrogen so that it can be then shrunk fit into the girder. On one occasion in Florida, when the trunnion-hub assembly was put into liquid nitrogen, development of cracks on the hub was observed. Experimental and numerical studies conducted since 1998 at University of South Florida show that the cracking took place due to combination of high interference stresses in the trunnion-hub assembly, low fracture toughness of steel at cryogenic temperatures, and steep temperature gradients due to sudden cooling. In this study, we are studying the benefit of staged cooling to avoid cracking in the trunnion-hub assembly when it is cooled down for shrink fitting. We looked at three cooling processes - 1) Direct immersion into liquid nitrogen 2) Immersion into a refrigerated chamber, then liquid nitrogen 3) Immersion into a refrigerated chamber, then a dry-ice/alcohol bath, and finally liquid nitrogen. The geometry of the trunnion-hub assembly was approximated by a composite made of two infinitely long hollows cylinders. The transient problem of temperature distribution and the resulting stresses was solved using finite difference method. Using critical crack lengths and Von-Mises stress as failure criteria, the three cooling processes were compared. The study showed that the minimum critical crack length and stress ratio is increased by as much as 200% when cooling first in refrigerated air followed by liquid nitrogen. However, there is little benefit from adding dry-ice/alcohol as an intermediate step in the cooling process.

World-wide coral reefs are in a state of decline as a result of many local and regional factors. Recent global mass mortalities of reef corals due to record warm sea temperatures have led researchers to consider global warming as one of the most significant threats to the persistence of coral reef ecosystems over the next 100 years. It is well established that elevated sea surface temperatures (SSTs) cause widespread coral bleaching, yet confusion lingers as to what facet of extreme temperatures is most important. Utilizing long-term in situ datasets, nine thermal stress indices were calculated and their effectiveness at segregating bleaching years a posteriori for multiple reefs on the Florida Reef Tract was tested. Simple bleaching thresholds based on deviations above the climatological maximum monthly SST were just as effective at identifying bleaching years as complex thermal stress indices. Near real-time bleaching alerts issued by NOAA's Integrated Coral Observing Network (ICON) are now based upon a running 30-day average SST, such that alerts are only issued when the running 30-day average SST exceeds the estimated bleaching threshold for a particular site. In addition to three widespread, mass-coral bleaching events, the Florida Reef Tract was impacted by three tropical storms and 12 hurricanes from 1997-2005. Sea surface cooling associated with the high frequency of hurricanes that impacted Florida in 2005 likely acted to ameliorate the severity and duration of bleaching. Nonetheless, hurricane-associated cooling is not expected to nullify the proposed effects of climate change on coral reefs. The role of thermal stress in coral bleaching has been extensively studied for eastern tropical Pacific (ETP) coral reefs. However, the ETP presents a unique opportunity as this region has sub-optimal conditions for coral reef development because of upwelling of carbon dioxide-enriched deep water along the shallow thermocline. This upwelling results in a depressed aragonite saturation state which is likely an additional factor in the poor reef development throughout the ETP. The highest aragonite saturation documented in this study occur in the Gulf of Chiriquí, which corresponds with the greatest reef development of the entire ETP. Seasonal upwelling had a significant effect on the carbonate chemistry of surface waters in Pacific Panamá. This regionally-depressed aragonite saturation state of the ETP appears to result in corals with a less dense skeleton. Density values of poritid corals from the Galápagos, where aragonite saturation was the lowest documented in this study, were significantly less dense relative to those from Panamá and the Great Barrier Reef. The density of non-living pocilloporid framework components were no different across the ETP aragonite saturation gradients. This could be a result of the activity of boring sponges removing the primary carbonate material within the dead coral skeleton, thus lowering density, albeit physical-chemical dissolution cannot be ruled out. These studies provide real-world examples of the ramifications of global climate change upon coral reef ecosystems.

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