The primary purpose of this doctoral dissertation was to investigate the effect of body temperature responses at physiologically relevant sites during an incremental exercise test on the phenomenon of exercise-induced hypoxemia (EIH). This phenomenon has been considered as an important limitation to physical performance with a prevalence of ~50 % in trained male athletes, but described in both sexes, across the range of both age and physical fitness in more recent literature. Previously this phenomenon has been described as a decrement in both arterial oxygen partial pressure (PaO₂) and oxy-haemoglobin saturation (SaO₂or SpO₂) with, particularly important for PaO₂, a lack of or inappropriate correction made for the change in body temperature during intense exercise. The initial study of this thesis determined the thermal response within the body at physiologically relevant sites measured simultaneously during an incremental exercise test. The results demonstrated the inadequacy of rectal temperature as an indicator of the acute temperature changes occurring during an incremental exercise test due to its slow response rate and relative thermal inertia. Radial arterial blood and oesophageal temperatures were shown to behave almost identically during the exercise test, albeit with an offset of approximately 1.3ºC, and were considered much more appropriate and relevant indicators of thermal changes during exercise. As an extension of the initial work active muscle temperature (vastus lateralis) was measured during the exercise test, demonstrating a significantly lower resting temperature than the oft-reported “core” temperatures (rectal and oesophageal) as well as a significantly greater increase in temperature in comparison to all other measurement sites. Overall, the results of this first study indicated that the physiologically relevant temperatures measured at the oesophageal and muscle sites differed markedly to the outdated rectal temperature measurement site and should be used as measures of thermal response when evaluating oxygen loading (oesophageal) or unloading (active muscle). Utilising the definition of EIH as a decrease in PaO₂ of ≥ 10 mmHg, the effect of temperature correcting PaO₂ was evaluated in the second study. Arterial blood gases measured simultaneously to the temperature measurements during the incremental exercise test were adjusted for the temperature changes at each site (every 1ºC increase in temperature will increase a PaO₂ value by ~5 mmHg). Whilst uncorrected PaO₂ values indicated an almost 100% prevalence of EIH in this group, oesophageal temperature corrected PaO₂ values decreased this prevalence to ~50% while muscle temperature corrections resolved all cases of EIH and demonstrated an HYPEROXAEMIA (i.e. the reverse of the well-established phenomenon) in the majority of subjects. Further investigation of arterial oxygen content during the exercise test indicates that there is no disruption in the delivery of oxygen to the active muscles and therefore any performance decrement should be attributed to another mechanism. Whilst the phenomenon of EIH is determined by the definition applied and the use of temperature corrections in the case of PaO₂, its reproducibility in a test-retest situation had not previously been determined. Utilising a subset of previously tested subjects, the reproducibility of both temperature and PaO₂ were determined with results indicating that the blood gas response was highly reproducible, especially the minimum PaO₂ value noted during each exercise test. However, comparing a more statistically relevant definition of a change in PaO₂ of ± 2 standard deviations from the mean resting PaO₂ to the previous delimiter of 10 mmHg indicated a lesser reproducibility of the prevalence of EIH. In summary, this thesis exposes the inadequacies of previous research into EIH with regard to the expected reproducibility of the phenomenon and the need to correctly adjust PaO₂ values for exercise-induce hyperthermia as well as demonstrating the difference in thermal responses to acute exercise in physiologically significant areas of the body. Furthermore, previously described correlations between the change in PaO₂ and VO₂ max were not evident in the subjects tested within this thesis, nor was there any indication of a diffusion limitation based on reduced pulmonary capillary transit time (by association with VO₂ max) or pulmonary oedema (rebuked by a rapid return of PaO₂ to above resting levels following exercise cessation). / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320633 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2008

Rotary air-to-air energy exchangers (also called energy wheels) transfer both heat and moisture between supply and exhaust airstreams in buildings. In this thesis, it is hypothesized that the transient step response characteristics of an energy wheel are uniquely related to the steady-state cyclic response of the wheel. The primary objective of this research is to study the transient response of a humidity/temperature sensor and measure energy wheel performance with a new test procedure that uses only transient response characteristics. In this thesis, the transient characteristics of a humidity/temperature sensor and an energy wheel to a step change in relative humidity and temperature are investigated through two types of measurements. One test uses a small airflow, at controlled temperature and humidity conditions, passing through a small section of a porous wheel while measuring the outlet conditions after the inlet conditions are suddenly changed. For a step input, it is shown that the outlet humidity/temperature sensor data correlate with an exponential function with two time constants. Since the transient response characteristics of the humidity/temperature sensor must be known to predict the response of the wheel alone, a second test is required that is similar to the first test except that the wheel is removed. This test is used to obtain the transient response of the sensor alone. Data from these tests show that both the sensor and the sensor plus wheel have two sets of two time constants. An analysis is presented to determine the transient response of the wheel alone using the correlated properties of the sensor alone and the sensor with a wheel upstream. The challenge undertaken in this research was the development of a more flexible, lower cost test facility than that presented in ASHRAE Standard 84-1991(Method of Testing Air-to-Air Heat Exchangers). In future work, this new laboratory experimental test facility should be adapted to test most types of energy wheels. The configuration allows a wide range of mass flow rates, inlet supply air temperatures and relative humidities. Uncertainty analysis is used for each transient test for the sensors and air-to-air energy wheels to specify the sensor and wheel plus sensor characteristics. This uncertainty analysis shows that accurate sensor calibration under equilibrium conditions and the start time for the humidity sensor step change is crucial to achieve low uncertainties in the transient behaviour of sensor and energy wheels. Knowing the uncertainty in the characteristics of the sensors and the wheel plus sensors the uncertainty in the transient response of the wheel alone is predicted. The first time constant of the humidity sensor is found to be about 3 seconds, while the second time constant is found to be about 100 seconds. It is found that the predicted response of the wheel alone gives time constants that are about 6 seconds and 140 seconds. Other researchers can use this information presented in this thesis to estimate the effectiveness of an energy wheel.

Rotary air-to-air energy exchangers (also called energy wheels) transfer both heat and moisture between supply and exhaust airstreams in buildings. In this thesis, it is hypothesized that the transient step response characteristics of an energy wheel are uniquely related to the steady-state cyclic response of the wheel. The primary objective of this research is to study the transient response of a humidity/temperature sensor and measure energy wheel performance with a new test procedure that uses only transient response characteristics. In this thesis, the transient characteristics of a humidity/temperature sensor and an energy wheel to a step change in relative humidity and temperature are investigated through two types of measurements. One test uses a small airflow, at controlled temperature and humidity conditions, passing through a small section of a porous wheel while measuring the outlet conditions after the inlet conditions are suddenly changed. For a step input, it is shown that the outlet humidity/temperature sensor data correlate with an exponential function with two time constants. Since the transient response characteristics of the humidity/temperature sensor must be known to predict the response of the wheel alone, a second test is required that is similar to the first test except that the wheel is removed. This test is used to obtain the transient response of the sensor alone. Data from these tests show that both the sensor and the sensor plus wheel have two sets of two time constants. An analysis is presented to determine the transient response of the wheel alone using the correlated properties of the sensor alone and the sensor with a wheel upstream. The challenge undertaken in this research was the development of a more flexible, lower cost test facility than that presented in ASHRAE Standard 84-1991(Method of Testing Air-to-Air Heat Exchangers). In future work, this new laboratory experimental test facility should be adapted to test most types of energy wheels. The configuration allows a wide range of mass flow rates, inlet supply air temperatures and relative humidities. Uncertainty analysis is used for each transient test for the sensors and air-to-air energy wheels to specify the sensor and wheel plus sensor characteristics. This uncertainty analysis shows that accurate sensor calibration under equilibrium conditions and the start time for the humidity sensor step change is crucial to achieve low uncertainties in the transient behaviour of sensor and energy wheels. Knowing the uncertainty in the characteristics of the sensors and the wheel plus sensors the uncertainty in the transient response of the wheel alone is predicted. The first time constant of the humidity sensor is found to be about 3 seconds, while the second time constant is found to be about 100 seconds. It is found that the predicted response of the wheel alone gives time constants that are about 6 seconds and 140 seconds. Other researchers can use this information presented in this thesis to estimate the effectiveness of an energy wheel.

Interactions between an intense laser pulse and cluster targets are investigated using the recent experimental results of the cluster fusion experiments on the Texas Petawatt Laser (TPW). We achieved about 2x10⁷ DD fusion neutrons per shot on the TPW by optimizing the laser and gas jet parameters. A few different types of cluster targets were used on the TPW including deuterium clusters, deuterated methane clusters, deuterium cluster + helium-3 mixture, and deuterated methane cluster + helium-3 mixture. We designed our own neutron detectors and proton detectors for the measurements of the fusion yields. The calibration method of neutron detectors is described in detail. Through the yield measurements of the 2.45 MeV neutrons from the DD fusion reactions and 14.7 MeV protons from the D-³He fusion reactions in the deuterium-helium-3 mixture target, we successfully measured the ion temperature of the fusion plasma at the time of the fusion reactions. / text

The negative consequence of recent climate change on the Earth’s biodiversity has become more evident in recent years. Some animals, due to insularity or habitat fragmentation, are unable to shift their ranges altitudinally and latitudinally. Vulnerable species need to rely on behavioural and, more importantly, physiological responses in order to persist through present climatic changes. It has therefore become more obvious that physiological responses of individuals need to be incorporated into predictive models of the responses of mammals to accelerated climate change. The primary purpose of this study was to test the ‘Hyperthermic Daily Torpor’ hypothesis proposed recently by Lovegrove et al., (in press). The hypothesis suggests that, based on albeit limited evidence, some small mammals may be capable of hyperthermia induced hypometabolism equivalent to that experienced during torpor and hibernation in response to cold temperatures. These authors argue that such hyperthermic hypometabolism should reduce the risk of entry into pathological hyperthermia and also reduce the rate of water loss driven by heat-induced evaporative cooling. The reaction norms of desert mammals have been selected to be adaptive over a wide range of climatic conditions due to the unpredictability of their habitat. Thus, they are good models for testing the reaction norms that may be expressed in response to accelerated climate change. We therefore tested our hypothesis using two presumably heat-adapted desert rodents; the Namaqua rock mouse, Aethomys namaquensis, and the pygmy rock mouse, Petromyscus collinus, as model species. We used indirect respirometry to measure metabolic rate at high ambient temperatures. We progressively exposed the animals to high temperatures to induce thermal tolerance and thus minimize the risks of lethal hyperthermia. We also measured subcutaneous and core temperatures, using temperature-sensitive PIT tags (BioTherm Identipet) and modified iButtons (Maxim Integrated), respectively. A. namaquensis displayed the capacity for hyperthermia-induced hypometabolism (Q10 79 = 1.27 ± 1.61) whereas the P. collinus did not (Q10 = 2.45 ± 1.41). The implications of such a physiological response in A. namaquensis are crucial in terms of its capacity to minimize the risks of lethal, pathological hyperthermia. Recent models of endothermic responses to global warming based on ectothermic models predict a dichotomy in the thermoregulatory responses of mammals to high temperatures. This study, to our knowledge, provides some of the first data on these interspecific variations in the thermoregulatory responses of mammals to high temperatures. However, the different physiological responses to hyperthermia between these two species cannot be meaningfully interpreted without phylogenetically independent comparisons with other species, that is, a more expansive interspecific analysis. Nonetheless, we provide some autecological sketches to assist in future multivariate interspecific analyses. Physiological differences between captive or captive-bred and free-ranging mammals preclude the extrapolation of our findings to free-ranging mammals. It is almost impossible to collect MR data in the field, although a few authors have successfully done so, and it is often not feasible to collect Tb data in small free-ranging mammals. Most studies have therefore made use of externally-mounted temperature-sensitive data loggers in order to collect Tskin data as a proxy for Tcore data in free-ranging mammals. However, misleading gradients between Tskin and Tcore can occur if data loggers are placed too close to major-heat producing tissues and the effects of the external environment on these data loggers may result in large Tskin – Tcore gradients. The second objective of this thesis therefore was to test the validity of using subcutaneous temperatures (Tsub) from subcutaneously injected temperature-sensitive PIT tags as a proxy for Tcore using the Namaqua rock mouse, Aethomys namaquensis. We found that the difference between Tcore and Tsub was minimal (~ 0.34˚C) within the thermoneutral zone (TNZ) with slight, non-significant, differences outside the TNZ. There was a tendency for Tsub to underestimate Tcore below thermoneutrality and overestimate it above thermoneutrality. We attributed these differences to the various heat loss and heat gain mechanisms activated in response to heat and cold stress in order to maintain a setpoint Tb. Nevertheless, we found that the Tcore – Tskin differential never exceeded 1.59˚C above the wide 108 range of Tas (5˚ – 41˚C) measured. Thus, we can conclude that subcutaneous temperatures provide a reasonably reliable proxy for core temperature in small mammals. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Methods of temperature measurement by mass spectrometry have been critically reviewed. It was concluded that the most appropriate method depended critically on the availability of fundamental data, hence a database of fundamental spectroscopic constants, for diatomic ions which cause interferences in ICP-MS, was compiled. The equilibration temperature, calculated using the different methods and using various diatomic ions as the thermometric probes, was between c.a. 400 - 10,000 K in the central channel, and between c.a. 600 - 16,000 K when the plasma was moved 1.8 mm off-centre. The wide range in temperature reflected the range of temperature measurement methods and uncertainty in the fundamental data. Optical studies using a fibre optic connected to a monochromator were performed in order to investigate the presence of interferences both in the plasma and the interface region of the ICP-MS, and the influence of a shielded torch on these interferences. It was possible to determine the presence of some species in the plasma, such as the strongly bound metal oxides, however, no species other than OH were detected in the interface region of the ICP-MS. The OH rotational temperature within the interface region of the ICP-MS was calculated to be between 2,000 - 4,000 K. The effect of sampling depth, operating power, radial position and solvent loading, with and without the shielded torch, on the dissociation temperature of a variety of polyatomic interferences was investigated. These calculated temperatures were then used to elucidate the site of formation for different polyatomic interferences. Results confirmed that strongly bound ions such as MO+ were formed in the plasma, whereas weakly bound ions such as ArO+ were formed in the interface region due to gross deviation of the calculated temperatures from those expected for a system in thermal equilibrium.

The primary purpose of this doctoral dissertation was to investigate the effect of body temperature responses at physiologically relevant sites during an incremental exercise test on the phenomenon of exercise-induced hypoxemia (EIH). This phenomenon has been considered as an important limitation to physical performance with a prevalence of ~50 % in trained male athletes, but described in both sexes, across the range of both age and physical fitness in more recent literature. Previously this phenomenon has been described as a decrement in both arterial oxygen partial pressure (PaO₂) and oxy-haemoglobin saturation (SaO₂or SpO₂) with, particularly important for PaO₂, a lack of or inappropriate correction made for the change in body temperature during intense exercise. The initial study of this thesis determined the thermal response within the body at physiologically relevant sites measured simultaneously during an incremental exercise test. The results demonstrated the inadequacy of rectal temperature as an indicator of the acute temperature changes occurring during an incremental exercise test due to its slow response rate and relative thermal inertia. Radial arterial blood and oesophageal temperatures were shown to behave almost identically during the exercise test, albeit with an offset of approximately 1.3ºC, and were considered much more appropriate and relevant indicators of thermal changes during exercise. As an extension of the initial work active muscle temperature (vastus lateralis) was measured during the exercise test, demonstrating a significantly lower resting temperature than the oft-reported “core” temperatures (rectal and oesophageal) as well as a significantly greater increase in temperature in comparison to all other measurement sites. Overall, the results of this first study indicated that the physiologically relevant temperatures measured at the oesophageal and muscle sites differed markedly to the outdated rectal temperature measurement site and should be used as measures of thermal response when evaluating oxygen loading (oesophageal) or unloading (active muscle). Utilising the definition of EIH as a decrease in PaO₂ of ≥ 10 mmHg, the effect of temperature correcting PaO₂ was evaluated in the second study. Arterial blood gases measured simultaneously to the temperature measurements during the incremental exercise test were adjusted for the temperature changes at each site (every 1ºC increase in temperature will increase a PaO₂ value by ~5 mmHg). Whilst uncorrected PaO₂ values indicated an almost 100% prevalence of EIH in this group, oesophageal temperature corrected PaO₂ values decreased this prevalence to ~50% while muscle temperature corrections resolved all cases of EIH and demonstrated an HYPEROXAEMIA (i.e. the reverse of the well-established phenomenon) in the majority of subjects. Further investigation of arterial oxygen content during the exercise test indicates that there is no disruption in the delivery of oxygen to the active muscles and therefore any performance decrement should be attributed to another mechanism. Whilst the phenomenon of EIH is determined by the definition applied and the use of temperature corrections in the case of PaO₂, its reproducibility in a test-retest situation had not previously been determined. Utilising a subset of previously tested subjects, the reproducibility of both temperature and PaO₂ were determined with results indicating that the blood gas response was highly reproducible, especially the minimum PaO₂ value noted during each exercise test. However, comparing a more statistically relevant definition of a change in PaO₂ of ± 2 standard deviations from the mean resting PaO₂ to the previous delimiter of 10 mmHg indicated a lesser reproducibility of the prevalence of EIH. In summary, this thesis exposes the inadequacies of previous research into EIH with regard to the expected reproducibility of the phenomenon and the need to correctly adjust PaO₂ values for exercise-induce hyperthermia as well as demonstrating the difference in thermal responses to acute exercise in physiologically significant areas of the body. Furthermore, previously described correlations between the change in PaO₂ and VO₂ max were not evident in the subjects tested within this thesis, nor was there any indication of a diffusion limitation based on reduced pulmonary capillary transit time (by association with VO₂ max) or pulmonary oedema (rebuked by a rapid return of PaO₂ to above resting levels following exercise cessation). / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320633 / Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2008

L'objectif de la thèse est de développer des systèmes de Barrières Thermiques (BT) « capteurs » base zircone yttriée (ZrO2 + 9.8mol% Y2O3, YSZ) déposés par voie sol-gel selon un procédé de trempage-retrait. Ceux-ci sont dédiés à la mesure de la température par des méthodes de thermométrie par fluorescence et au suivi de l'endommagement dans l'épaisseur des revêtements. Les méthodes proposées sont basées sur le suivi de l'évolution, notamment avec la température, des propriétés de photoluminescence de marqueurs fluorescents lanthanides Ln3+, tels que l'europium Eu3+, le dysprosium Dy3+, l'erbium Er3+, le samarium Sm3+ ou encore le thulium Tm3+. Ceux-ci sont directement incorporés dans la structure de la zircone, semi-transparente dans le domaine d'émission visible de ces marqueurs. Un banc de mesure des propriétés de fluorescence (spectres, intensités et temps de vie) a spécifiquement été développé dans ce but. La caractérisation des différents couples YSZ:Ln3+ sous forme de poudres synthétisées par voie sol-gel a permis d'optimiser les compositions de manière à maximiser l'intensité du signal de fluorescence tout en préservant les propriétés microstructurales requises pour une BT. Les dépôts sol-gel réalisés par trempage-retrait permettent la fabrication de prototypes de BT multicouches fonctionnalisées intégrant jusqu'à trois couches fluorescentes de longueurs d'onde d'émission distinctes. De tels systèmes architecturés permettent de sonder optiquement la totalité de l'épaisseur de zircone déposée pour de futures applications visant à évaluer les gradients thermiques siégeant dans le volume des revêtements. Des BT fonctionnalisées contenant des défauts de délamination pré-calibrés à l'interface métal/céramique ont été également utilisées pour comparer l'intérêt d'une méthode de fluorescence accrue par réflectance et d'une méthode de thermographie infrarouge pour le suivi et l'évaluation des processus d'endommagement précurseurs de l'écaillage. Enfin, le potentiel qu'offrent les poudres de zircone YSZ:Ln3+ dopées en tant que marqueurs fluorescents de l'histoire thermique, alternatifs aux peintures thermiques utilisées industriellement, a aussi été analysé. / The aim of this work is to develop and study yttria stabilised zirconia (ZrO2 + 9.8at% Y2O3, YSZ) based thermal barrier coating (TBC) « sensor » systems deposited by a dip coating sol-gel process, and dedicated to temperature measurement and to the monitoring of damaging occuring within the thickness of the coatings, using fluorescence thermometry methods. These methods are based on the monitoring of the fluorescence properties of photoluminescent activators from the trivalent lanthanide ions group (Ln3+), such as samarium Sm3+, europium Eu3+, dysprosium Dy3+, erbium Er3+ and thulium Tm3+. These activators are directly incorporated into the zirconia YSZ host matrix lattice, which is semi-transparent at their emission wavelengths mainly falling in the visible range. An experimental set up was especially developped for the application of these methods. The characterisation of the different YSZ:Ln3+ powders synthesized by a sol-gel process allowed to optimise the compositions, and thus maximize the fluorescence signal intensity while avoidind any alteration of the zirconia crystal structure required from for a TBC material. The sol-gel dip coating process allowed to deposit functionalised multilayer TBC prototypes integrating up to three fluorescent layers with distinct emission wavelengths distributed throughout the thickness. Such coating architectures allow, with the fluorescence thermometry methods identified, to optically probe the coating across the whole thickness for future applications aiming to determine the thermal gradient in TBCs. Functionalised TBCs containing pre-calibrated delamination defects at the metal/ceramic interface were also used to compare the interest of the reflectance enhanced fluorescence method and an IR thermography method for early monitoring of TBC spallation. At last, the potential offered by YSZ:Ln3+ powders as thermal history sensors alternative to temperature sensitive paints was also investigated.

The master's thesis is devoted to the history and performance of non-contact temperature measurement, characterization of infrared cameras and infrared thermometers. Temperature is one of the most important physical quantities. Using an infrared camera we obtain information about the surface temperature in all picture. In the master's thesis is included the measurement and capturing the fatal defects on the punched billet, finding out the quality of temperature field and the quality of the overlapping work rolls. During the measurements were used infrared cameras TIM200, TIM400 from the company Micro-Epsilon and infrared cameras SC325, SC660 from the company Flir.

Made available in DSpace on 2014-10-09T12:34:46Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:29Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP