The Fluorescence Scanning Thermal Microscope (FSTM v3.0), was designed to create an inexpensive, and easily manufactured, device for measuring the diffusivity of samples with microscopic locational precision. This was accomplished by using a Blu-ray device known as a PHR-803T, referred to in this work as a PHR. The optics in the PHR are nearly identical in function to conventional devices used in thermoreflectance microscopy, making the PHR extremely useful to integrate into the FSTM design. The focus of this thesis is the application of the FSTM as a confocal microscope using 3D printed components and various low-cost devices to operate with comparable sampling accuracy to existing confocal microscopes. The electronics and optical filters were then adapted to enable the measurement of thermal waves, particularly by detecting a linear relationship between phase delay and the spacing between heating and sensing lasers, as predicted by previous work on the FSTM.

The Northern Highlands Terrane (NHT) in Scotland preserves a long record of metamorphism and convergent deformation related to several orogenic events that occurred from Neoproterozoic to Devonian time. Deconvolving the signatures of multiple tectonic events and determining the rates of metamorphism in settings like the NHT are important parts of better understanding the thermal and mechanical processes controlling convergent tectonics. I have used monazite-xenotime thermometry and geochronology, in conjunction with metamorphic petrology and additional accessory phase geochronology, to place constraints on the timing and rates of thermal metamorphism in a variety of structural settings throughout the NHT. Our data show that the ductile thrust nappes of northernmost Scotland preserve a record of Scandian (435-410 Ma) orogenesis. High grade metamorphism in the hinterland Naver nappe likely resulted from the widespread infiltration of granitic magmas at c. 425 Ma, which coincided with peak metamorphism. The timing of metamorphism in the hinterland Scandian thrust nappes is apparently younger than at least some deformation in the foreland Moine thrust zone, suggesting this orogenic wedge experienced large-scale out-of-sequence deformation and metamorphism. In contrast to the Scandian nappes, the Sgurr Beag nappe records primarily Precambrian metamorphism related to the Knoydartian orogeny (780-725 Ma). Additionally, monazite in the Sgurr Beag nappe preserves a record of widespread metasomatism and metamorphism at c. 600 Ma, possibly related to the break-up of Rodinia at that time. A potentially important heat source in orogenic systems, like those preserved in Scotland, is the thermal energy dissipated during deformation, otherwise known as shear heating. It is important to consider to how shear heating may contribute to metamorphism during orogenesis. This is challenging because there are few, if any, methods of relating observations from typical orogenic systems to magnitudes of shear heating. We have developed a model that is adaptable to a wide range of parameters that can be measured from naturally deformed rocks and places first-order constraints on magnitudes of shear heating. While our models suggest that shear heating is not particularly important in the NHT, in lower initial temperature mylonite zones shear heating could be more significant. / Doctor of Philosophy / The Northern Highlands Terrane (NHT) in Scotland preserves a long record of metamorphism and convergent deformation related to several orogenic events that occurred from Neoproterozoic to Devonian time. Understanding the record of each of these events and the rates at which metamorphic changes occurred is important for improving our understanding of the processes at work in continental collisions. The work presented in this thesis involves determining the temperatures recorded by metamorphic minerals and the ages of those minerals in order to reconstruct the temperature-time evolution of samples in a variety of positions within the NHT. Our data show that the collision and thermal metamorphism at 435-410 Ma is well preserved in northernmost Scotland. We argue that metamorphism in this area resulted from the widespread intrusion of hot magmas, which coincided in time with peak metamorphism. The timing of metamorphism in the core (hinterland) of this mountain belt is apparently younger than shallower deformation at the edges (foreland) of the mountain belt, suggesting active deformation and metamorphism retreated toward the hinterland during crustal shortening. In another part of the NHT, known as the Sgurr Beag nappe, a much older metamorphic event that occurred at 780-725 Ma is better preserved. In this area, the mineral monazite appears to record evidence of widespread fluid alteration at ~600 Ma, which has not previously been widely recognized in Scotland. A potentially important heat source in the Earth’s crust is shear heating associated with the thermal energy produced during deformation. It is important to consider what contribution shear heating may have made to the preserved metamorphic record in orogenic belts. This is challenging because there are few, if any, methods of relating observations from typical metamorphic rocks to estimated magnitudes of shear heating. We have developed a numerical model that is adaptable to a wide range of realistic natural scenarios and places first-order constraints on potential magnitudes of shear heating. While our models suggest that shear heating is not particularly important in the NHT, in some lower temperature fault zones shear heating could be more significant.

Mantle plumes are anomalously hot, narrow upwellings of mantle material that originate at the core-mantle boundary. As plumes rise they may form volumetrically large "heads" (~1000 km in diameter) with narrower (~100 km) "tails." Plume head melting is thought to form Large Igneous Provinces (LIPs), vast outpourings of basaltic lava (~106 km3), while plume tail melting forms linear chains of ocean island basalts (OIBs) similar the Emperor-Hawaii Seamount chain. Mantle plume derived melts indicate that these structures sample deep Earth geochemical and lithological heterogeneities. Studying plume-derived lavas can clarify important planetary-scale questions relating to the accretion of the Earth, primordial geochemical reservoirs, the fate of subducted materials, planetary differentiation, and convective mixing. / Ph. D. / Mantle plumes are hot, narrow upwellings of plastically flowing mantle material. These structures are thought to originate at the core-mantle boundary. Because mantle plumes originate in the deep interior of the planet, they are though to sample both primitive materials that are remnants of Earth’s formation as well as recycled crustal materials that have been subducted from the surface into the deep interior of the planet. When mantle plumes near the surface of the planet they begin to partially melt during a process known as adiabatic decompression melting. When these melts cool, they crystallize to form basalts. These rocks and their associated minerals can be studied to determine lava temperatures and pressures of formation. The geologic record suggests that relatively recently mantle plumes cool and eventually become magmatically inactive. In this project, we used the Galapagos plume as a case study to investigate why it has systematically cooled over the last 90 Ma. The Galapagos mantle plume is possibly the oldest active plume and records a 90 Ma volcanic evolution. We studied Galapagos-related lavas and olivine crystals across the entire 90 Ma evolution of the plume to better understand the life-death cycle of mantle plumes. Our data suggest that the plume may be cooling due to an increase in the amount of recycled oceanic crust. Alternatively, a recycled oceanic crust component could have always been present in the source of the plume, though was diluted during high degrees of partial melting when it was hottest at 90 Ma.

Thermal management challenges for microelectronics are a major issue for future integrated circuits, thanks to the continued exponential growth in component density described by Moore¡¯s Law. Current projections from the International Technology Roadmap for Semiconductors predict that local heat fluxes will exceed 1 kW/cm2 within a decade. There is thus an urgent need to develop new compact, high heat flux forced-liquid and evaporative cooling technologies. Thermometry techniques that can measure temperature fields with micron-scale resolution without disturbing the flow of coolant would be valuable in developing and evaluating new thermal management technologies. Specifically, the ability to estimate local convective heat transfer coefficients, which are proportional to the difference between the bulk coolant and wall surface temperatures, would be useful in developing computationally efficient reduced-order models of thermal transport in microscale heat exchangers. The objective of this doctoral thesis is therefore to develop and evaluate non-intrusive optical thermometry techniques to measure wall surface and bulk liquid temperatures with O(1-10 micronmeter) spatial resolution. Intensity-based fluorescence thermometry (FT), where the temperature distribution of an aqueous fluorescent dye solution is estimated from variations in the fluorescent emission intensity, was used to measure temperatures in steady Poiseuille flow at Reynolds numbers less than 10. The flow was driven through 1 mm square channels heated on one side to create temperature gradients exceeding 8 ¡ÆC/mm along both dimensions of the channel cross-section. In the evanescent-wave fluorescence thermometry (EFT) experiments, a solution of fluorescein was illuminated by evanescent waves to estimate the solution temperature within about 300 nm of the wall. In the dual-tracer FT (DFT) studies, a solution of two fluorophores with opposite temperature sensitivities was volumetrically illuminated over most of the `cross-section of the channel to determine solution temperatures in the bulk flow. The accuracy of both types of FT is determined by comparing the temperature data with numerical predictions obtained with commercial computational fluid dynamics software. The results indicate that EFT can measure wall surface temperatures with an average accuracy of about 0.3 ¡ÆC at a spatial resolution of 10 micronmeter, and that DFT can measure bulk water temperature fields with an average accuracy of about 0.3 ¡ÆC at a spatial resolution of 50 micronmeter in the image plane. The results also suggest that the spatial resolution of the DFT data along the optical axis (i.e., normal to the image plane) is at least an order of magnitude greater than the depth of focus of the imaging system.

Technological advances in clinical thermometers have resulted in a variety of minimally invasive devices that give rapid results but may not have the accuracy necessary for use in acutely ill adults. Inaccurate temperatures can result in missed opportunities for the early identification and treatment of infection and sepsis. Following the methodology outlined by Whittemore and Knafl, the purpose of this project was to conduct an integrative review of the research on the accuracy of clinical thermometers used for acutely ill adults. The evidence was categorized using the Hierarchy of Evidence for Interventional Studies, and the quality of the studies was appraised using the indicators described by Hooper and Andrews. Forty-seven studies met the inclusion criteria; the findings on device accuracy were contradictory. Device accuracy was found in 10 (n = 27) studies on the tympanic (TM), 2 (n = 8) on the chemical dot (CH), 7 (n = 19) on the temporal artery (TAT), and 3 (n = 13) on the axillary (AX) thermometers. Two of 2 studies found the no-touch (NT) device clinically inaccurate. Diagnostic accuracy was found in 3 (n = 8) and 0 (n = 5) studies on the TM and TAT, respectively. Only 22 studies had an acceptable quality grade of A or B, limiting the validity of the evidence. The evidence did not support the use of the NT and TAT thermometers or the AX route for acutely ill adults. The CH device should be use with caution, and abnormal temperatures should be validated with a more reliable device. For thermometers in use, appropriate training and technique are essential for the most accurate results. Closing the knowledge-to-practice gap on clinical thermometers can change the culture of nursing practice, improve early sepsis identification, and increase the quality of patient care.

Les ultrasons focalisés de haute intensité (HIFU) guidés par IRM et combinés à la thermométrie basée sur la fréquence de résonance du proton (PRF) sont une technique prometteuse pour l’ablation non invasive de tumeurs, le dépôt local de médicaments et l’activation des transgènes. Ce travail présente de nouveaux développements dans le domaine de la thermométrie PRF en présence de mouvement physiologique périodique associé aux variations du champ magnétique. De nouvelles stratégies de correction sont proposées et exploitent la méthode multi-baseline établie en incluant un modèle de variation de phase. Elles sont illustrées avec des exemples de thermométrie dans le sein et dans le cœur humain. De plus, d’autres facteurs influençant la thermométrie PRF, notamment la présence de graisse dans le sein et le flux sanguin dans le cœur, sont étudiés. Dans la seconde partie de ce travail a été abordée la problématique du contrôle précis de la température. Une première approche propose un algorithme de contrôle proportionel, intégral et dérivatif (PID) amélioré utilisant des paramétres de contrôle adaptatifs. En étendant ce concept à un contrôle 3D de la température, une implémentation de chauffage volumétrique est proposée. Par ailleurs, une nouvelle méthode de repositionnement dynamique de la coupe d’imagerie permet de fournir des informations volumétriques sur l’anatomie et la température en temps réel. La combinaison avec la compensation 2D de mouvement et l’adaptation du faisceau ultrasonore permet la réalisation d’un chauffage volumétrique suivant une courbe de température ou de dose thermique prédéfinie qui fonctionne même en présence de mouvements. / MR-guided high-intensity focused ultrasound (HIFU) using proton resonance frequency (PRF) based thermometry is a promising technique for non-invasive ablations in tumor therapy as well as for targeted drug delivery and the activation of transgenes. This work presents further developments in the field of PRF thermometry in the presence of periodical physiological motion and the associated magnetic field variations. Using the examples of thermometry in the human breast and the human heart, new correction strategies are presented which extend the established multi-baseline phase correction to include a model of the phase variation and external sensor readings from a pencil-beam navigator. In addition further factors, namely the presence of fat in the breast and blood flow in the heart influencing the performance of MR thermometry in these organs are examined.In the second part of this work, the issue of precise temperature control has been approached in two ways. First, an improved proportional, integral and derivative (PID) controller using adaptive control parameters is developed. By expanding the concept of temperature control to 3D, an implementation of volumetric heating is presented. A novel slice sweep technique provides volumetric anatomic and temperature information in near-real time. The combination with 2D motion compensation and adaptation of the ultrasound beam position allows to achieve volumetric heating according to a pre-defined target temperature or thermal dose value even in the presence of motion.

Thesis advisor: Michael Graf / The purpose of this dissertation was to investigate the temporal limit on the ability to measure temperature changes using magnetic resonance imaging (MRI). The limit was examined in experiments using a variety of imaging techniques for MRI-based temperature measurements. We applied these methods for monitoring temperature changes in focused ultrasound (FUS) heating experiments. FUS is an attractive alternative to surgical resection due to its noninvasive character. FUS treatments have been successfully conducted in several clinical applications. MRI and MR thermometry is a natural choice for the guidance of FUS surgeries, given its ability to visualize, monitor, and evaluate the success of treatments. MR thermometry, however, can be a very challenging application, as good resolution is often needed along spatial, temporal as well as temperature axes. These three quantities are strictly related to each other, and normally it is theoretically impossible to simultaneously achieve high resolutions for all axes. In this dissertation, techniques were developed to achieve this at cost of some reduction in spatial coverage. Given that the heated foci produced during thermal therapies are typically much smaller than the anatomy being imaged, much of the imaged field-of-view is not actually being heated and may not require temperature monitoring. By sacrificing some of the in-plane spatial coverage outside the region-of-interest (ROI), significant gains can be obtained in terms of temporal resolution. In the extreme, an ROI can be chosen to be a narrow pencil-like column, and a sampling time for temperature imaging is possible with a temporal resolution of a few milliseconds. MRI-based thermal imaging, which maps temperature-induced changes in the proton resonance frequency, was implemented in two projects. In the first project, three previously described, fast MR imaging techniques were combined in a hybrid method to significantly speed up acquisition compared to the conventional thermometry. Acceleration factors up to 24-fold were obtained, and a temporal resolution as high as 320 milliseconds was achieved. The method was tested in a gel phantom and in bovine muscle samples in FUS heating experiments. The robustness of the hybrid method with respect to the cancellation of the fat signal, which causes temperature errors, and the incorporation of the method into an ultrafast, three dimensional sequence were also investigated. In the second project, a novel MR spectroscopic sequence was investigated for ultrafast one-dimension thermometry. Temperature monitoring was examined during FUS sonications in a gel phantom, SNR performance was evaluated in vivo in a rabbit brain, and feasibility was tested in a human heart. It was shown capable in a FUS heating experiment in a gel phantom of increasing temporal resolution to as high as 53 milliseconds in a three Tesla MRI. The temporal resolution achieved is an order of magnitude faster than any other rapid MR thermometry sequences reported. With this one-dimensional approach, a short sampling time as low as 3.6 milliseconds was theoretically achievable. However, given the SNR that could be achieved and the limited heating induced by FUS in the gel phantom in a few milliseconds, any temperature changes in such a short period were obscured by noise. We have analyzed the conditions whereby a temporal resolution of a few-milliseconds could be obtained. / Thesis (PhD) — Boston College, 2011. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.

During gas turbine development testing, measurements of the gas-path stagnation temperature are used to characterise the engine running condition and establish individual engine component performance. These measurements are typically acquired using passively ventilated thermocouple probes, which are capable of achieving absolute stagnation temperature uncertainties of approximately 0.5 %. Historically, this measurement accuracy has been considered adequate to evaluate gains in turbomachinery efficiency. However, realisable turbomachinery efficiency gains have recently become sufficiently small that an improvement in measurement accuracy is now required. This has resulted in the specification of a target absolute stagnation temperature uncertainty of 0.1 %. The research presented in this thesis focusses on the development of a new stagnation temperature probe that will achieve a measurement uncertainty close to the target value. The new probe has been designed to utilise a thin-film platinum resistance thermometer (PRT) as the temperature sensitive element. For certain aspects of gas turbine engine testing, this type of sensor offers an improvement in measurement accuracy compared to a thermocouple.

Pour réduire significativement les émissions de CO2 dans les moteurs à combustion interne, un levier majeur est la réduction des pertes thermiques pariétales lors de la combustion. Ces pertes présentent un pic de plusieurs MW/m2 près du point mort haut, et sont liées à des phénomènes complexes d'interaction flamme-paroi qui dépendent du mode de combustion. Afin de mieux appréhender les phénomènes associés, il est nécessaire de caractériser le flux thermique à des échelles temporelles inférieures à la milliseconde.Dans ces travaux, une machine à compression rapide et une cellule à précombustion à volume constant sont utilisées pour simuler les phénomènes de combustion rencontrés en moteurs. Des thermocouples à jonction fines permettent une mesure de flux thermique instantanée avec une résolution temporelle de 0.1 ms. Ces moyens d'essais permettent de reproduire trois modes de combustion : flamme de propagation, flamme de diffusion et auto-inflammation. Ces travaux permettent également d'évaluer les différentes technologies envisageables de mesure de transfert thermique en combustion (thermocouples, thermorésistances et thermométrie phosphore rapide) au regard des caractéristiques métrologiques requises par la rapidité des phénomènes mis en jeu.Le flux lors du transfert thermique atteint des valeurs de plusieurs MW/m2 avec une forme qui dépend du mode de combustion. Le flux lors de la propagation d'une flamme prémélangée est dominé par un pic lors de l'interaction flamme paroi,d'environ 5 MW/m2 et de durée 0.5 ms. Le flux lors de la combustion d'un jet Diesel est approximativement un plateau pendant la durée de l'injection ; il est dominé par l'effet d'entraînement d'air par le jet qui cause une augmentation du coefficient de transfert convectif jusqu'à des valeurs de 10 kW/m2/K, l'augmentation de température liée à la combustion étant secondaire. Dans le cas d'ondes de pression générées par une auto-inflammation rapides de gaz(cliquetis lors d'un allumage commandé ou HCCI à fort contenu énergétique), une corrélation est observée entre l'intensité du cliquetis et le flux thermique associé, quel que soit le mode de combustion qui génère les oscillations de pression. Le flux lors du cliquetis est 3 à 5 fois plus élevé que lors d'une combustion par flamme de propagation comparable. / CO2 emissions in internal combustion engines are linked with inefficiencies due to wall heat losses during combustion.Those losses exhibit a sharp peak of a few MW/m2 close to top dead center and are linked to complex flame/wall interaction phenomena that vary with the combustion mode. A fine understanding of the associated phenomena requires experimental characterization of wall heat flux with a time resolution better than the millisecond. In this PhD work, a rapid compression machine and a precombustion cell are used to reproduce engine combustion phenomena. Thin-junction thermocouples allow an instantaneous measurement of the wall heat flux with a time resolution of 0.1 ms. Three combustion modes are generated: propagation flame, diffusion flame and auto-ignition.Different possible measurement technologies and procedures (thermocouples, thermoresistances and rapid phosphor thermometry) are compared and benchmarked against the features of combustion phenomena. Flux during wall heat transfer reaches values of a few MW/m2 and its shape varies with the combustion mode. During premixed flame propagation, flux is dominated by a peak during flame-wall interaction of about 5 MW/m2 in amplitude and 0.5 ms in duration. During Diesel combustion, heat flux is approximately constant during the injection duration; itsevolution is driven by an increase of the convection coefficient up to 10 kW/m2/K, which is attributed to air entrainment by the spray; the temperature increase from combustion is considered a second-order effect. During combustion presenting a pressure wave propagation (e.g. knock for some spark-ignition cases or HCCI with high energy content), the intensity of pressure oscillations and wall heat flux are shown to be correlated. That correlation is independent of the phenomenon creating the pressure wave; heat flux during knock is 3-5 times higher than for a comparable premixed propagation flame.

In this work we explore two novel uses of microwave technology in biomedical applications. Introductory material on the electrical properties of biological tissues is presented to form the groundwork for the basic theory behind both techniques. First, we develop a technique that uses 60 GHz signals to detect changes in blood oxidation levels. Several atmospheric propagation models are adapted to predict oxygen resonance spectra near this frequency. We are able to predict and observe the changes in these levels as the blood ages up to 48 hours. Identical testing procedures performed using arterial blood gas (ABG) calibration samples with controlled oxygen levels show similar results to those obtained as bovine blood ages. We then discuss a potential application of this technique to the detection and diagnosis of skin cancer. The second application involves non-invasive measurement of internal body temperatures. Conventional methods of body temperature measurement provide a numerical value for a specific location on the body. This value is then applied to the remaining body systems as a whole. For example, a measurement of 37° C obtained orally can possibly lead to the erroneous conclusion that temperature is normal throughout the body. Temperature measurements made on specific internal organs can yield more information about the condition of the body, and can be invaluable as a tool for performing remote diagnostic evaluations. We explore the use of microwave radiometry in the low GHz spectrum to show that temperature information can be obtained directly and non-invasively for internal organs. We use the principles of black-body radiation theory combined with the reflection and transmission characteristics of biological tissues to predict the temperature delta that would be externally measured, given specific changes in the internal temperature. Data taken using a microwave radiometer and planar structures made with biological phantoms are compared to analytical results, showing that detection of internal temperature changes of can be performed externally in this manner.