Thesis (M.S.)--University of Michigan, 2007. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 90-93).

The ultimate application of this work is constraining the optical properties of cirrus particles, which are poorly understood, by providing an automatic method, using all-sky cameras and an infrared radiometer, to identify the occurrence of the 22° halo formed by cirrus. This is done by interpreting all sky images in terms of a scattering phase function (SPF), from which the halo ratio (HR) is calculated, and by implementing a cirrus detection algorithm to associate HR measures to ice cloud occurrences. Cirrus reflectivity at solar wavelengths is inversely related to the HR which, being an indirect measure of the regularity of the shape of the ice crystals forming the cloud, relates in turn inversely to the asymmetry parameter g. Therefore, the method proposed here to derive statistics of HRs is expected to reduce the uncertainty over the optical and microphysical properties of cirrus. The light intensity measured by the all sky camera is transformed into a scattering phase function, from which the halo formation is identified. This is done by developing image transformations and corrections needed to interpret all sky images quantitatively in terms of scattering phase function, specifically by transforming the original image from the zenith-centred to the light-source-centred system of coordinates and correcting for the air mass and for vignetting. The SPF is then determined by averaging the image brightness over the azimuth angle and the HR by calculating the ratio of brightness at two scattering angles in the vicinity of the 22° halo peak. The instrument transformation and corrections are performed using a series of Matlab scripts. Given that the HR is an ice cloud characteristic and since the method needs additional temperature information if the halo observation is to be associated with cirrus, a cirrus detection algorithm is necessary to screen out non-ice clouds before deriving reliable HR statistics. Cloud detection is determined by quantifying the temporal fluctuations of sky radiance, expressed as brightness temperature (BT), through De-trended Fluctuation Analysis and setting a clear sky fluctuation threshold. Cloud phase discrimination instead is achieved through first constructing an analytic radiative transfer model to obtain an estimate for average molecular absorption cross-section of water vapour within the spectral window of the radiometer. This is done to model the down-welling clear sky radiance, which is in turn used to correct cirrus emissivity and ultimately determine a dynamic BT threshold for the transition from ice to liquid-containing clouds. In addition to the molecular cross section the screen level air temperature and integrated water vapour are used as input parameters to the model. The utilisation of the all sky camera for such quantitative measurement was the particularly novel aspect of this work; this has not been done previously to the best of my knowledge. The cirrus detection method proposed is also innovative in that with respect to previous works it does not rely on the use of additional techniques such as LIDAR or microwave radiometry for discriminating cloud phase. Furthermore, the cirrus threshold proposed is not fixed but accounts for the attenuating properties of the atmosphere below the cloud. Once the cirrus detection algorithm is validated and cirrus occurrences determinable, the HR could be extended to estimating the asymmetry parameter and crystal roughness. These are retrievable, for instance, from in-situ observations of single ice crystal 2D scattering patterns from cloud probes of the SID (Small Ice Detector) type. This would be significant for the constraining of the optical and microphysical properties of cirrus.

L’objectif de ce projet est de développer des méthodes d’analyse et de caractérisation des défauts structurels des matériaux s’appuyant sur la thermographie infrarouge stimulée. Nous pouvons à l’aide d’une excitation photothermique distante et d’un outil d’analyse que nous avons développé en laboratoire, déterminer la structure sous jacente d’un matériau, repérer précisément ses défauts et les mesurer. L’application qui nous intéresse ici porte sur la prévention, le diagnostique et la restauration des oeuvres d’art, nous avons démontré par de précédents travaux, la pertinence de cette approche et son potentiel important dans de nombreux domaines, qu’ils soient industriels, culturels, médicales ou autres. Nous avons fait la démonstration qu’il était possible d’analyse des matériaux fragiles de façon fiable et sans contact et nous comptons généraliser cette approche en l’étendant dans ses domaines d’intervention et dans sa précision. / The objective of this project is to develop analysis and characterization of structural defects in material methods based on photothermal radiometry,We can by means of a remote photothermal excitation and an analysis tool that we have developed in the laboratory to determine the underlying structure of a material, precisely locate its flaws and measure. The application of interest here focuses on the prevention, diagnosis and restoration of works of art, we have demonstrated by previous work, the relevance of this approach and its significant potential in many areas, such as industrial cultural, medical or other. We have demonstrated that it was possible to analyze fragile materials reliably and without contact and we intend to generalize this approach by extending its focal areas and its accuracy.

La radiométrie photothermique (PTR) est une technique standard qui mesure les propriétés thermiques en mesurant la réponse thermique d’un matériau à un échauffement optique. Le travail présenté ici développe la théorie PTR en prenant en compte la dépendance non linéaire des émissions thermiques par rapport à la température. Cette théorie PTR est explorée numériquement et expérimentalement dans ce travail en utilisant la dépendance non linéaire du rayonnement thermique en fonction de la température. Une technique de mesure de l'effusivité thermique et deux nouvelles techniques de pyrométrie sont développées et testées expérimentalement. La première technique de pyrométrie permet une mesure précise de l’augmentation de température lors d'une mesure PTR traditionnelle. Cela a de nombreuses applications lorsque l'échantillon est sensible à l’augmentation de température et peut être endommagé en raison d’une surchauffe. La deuxième technique de pyrométrie ne nécessite pas que l’émissivité soit connue, mesurée ou d’être basée sur l’hypothèse d’un corps gris. Cependant la mesure peut être fortement influencée par une erreur sur la bande passante des filtres optiques utilisés et elle est très sensible à toute non-linéarité dans le système de détection. À partir des résultats expérimentaux, des directives de conception sont fournies pour minimiser ces deux inconvénients. La troisième méthode développée permet une mesure directe et sans contact de l'effusivité thermique d'un matériau homogène. Ce type de mesure n'a encore jamais été réalisé avec d'autres techniques. Les résultats expérimentaux d'effusivité de cette technique montrent un excellent accord avec les valeurs de la littérature. / Photothermal radiometry (PTR) is a standard technique which measures thermal properties by measuring a materials thermal response due to optical heating. PTR measures the emitted thermal radiation from a sample to determine the thermal response. The work presented here further develops the PTR theory by including the nonlinear dependence of thermal emission with respect to temperature. This more advanced PTR theory is numerically and experimentally explored in this work. A thermal effusivity measurement technique and two new pyrometry techniques are developed and experimentally tested using the nonlinear dependence in the PTR theory. The first pyrometry technique allows for accurate temperature measurement during a traditional PTR measurement. This has many applications when the sample is sensitive to an increase in temperature and possibly damaged due to overheating. The second pyrometry technique does not require emissivity to be known, measured, or rely on a gray body assumption. The measurement can be influenced greatly by any error in the bandwidth of optical filters used in the measurement, and it is very sensitive to any nonlinearity in the detection system. From the experimental results, design guidelines are provided to minimize these two drawbacks of the technique for future exploration. The direct thermal effusivity measurement developed allows for a non-contact, direct measurement of thermal effusivity of a homogenous material. This type of measurement has not been achieved with any other technique. The experimental effusivity results from this technique show excellent agreement with literature values.

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No. of bitstreams: 2 Tese - Isabel Rodrigues da Rocha - 2018.pdf: 13506861 bytes, checksum: 62a627a5358951b6c7a08e05e36e6b7e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-05-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The development of mankind has always been connected to water resources. Currently, they have been more intensely exploited, especially in electrical power generation, through the opening of countless hydropower plants in Brazil from which many are found in the biome called Cerrado, due to its great water resources. From the need of studies on artificial reservoir once its made, the study on Salto do Rio Verdinho ́s river basin and waterpower plant ́s reservoir, located in the lower part of Verde river ́s river basin, close to Paranaíba river ́s downstream, tributary of Paraná river, was chosen. Verde river ́s flow is the verge of Caçu and Itarumã counties, in the south of Goiás state. Therefore, the main goal of this work is to comprehend the dynamics of usage and occupation of the river basin ́s lands and Salto do Rio Verdinho ́s waterpower plant relating to its water quality. With that in mind, the landscape was rated according to its physical features and the relation among its geology, soils, slope, geomorphology and remaining natural vegetation, based on the observation of the structural principle of the landscape, revealing that the environment of the river basin region belongs to Mesozoic era ́s geological formations, such as flattened relief and predominance of slope with very soft dissection between interfluves. Data on the changes in usage and occupation of the lands was possible through satellites images, where it was found that between 2005 and 2015, the main usage was pasture with 546 km2, the second, was areas intended to temporary cultures, with 237,4 km2. The analyses regarding the quality of the water from the reservoir, were made according to the resolution no 357 from 2005 of CONAMA, it was ranked as of very low quality due to its high percentage of nitrite and phosphorus. It was ranked as class 4. The variables: TDS and CE, Temp and TDS, Temp and CE, present significant correlations. The components optically active in the water (chlorophyll, concentration of suspended sediment, transparency and murkiness) that interfere in the electromagnetic spectra, present correlations with the measures of reflectance in the wavelength of 716 nm and 720 nm in January 2015, while the variables correlated better with the wavelength of 647 nm, 697 nm e 704 nm in February 2016, pointing that these wavelengths belong to the color red. The reflectance during the rainy months, January 2015 and February 2016, registered values between 0,04 and 0,23%, while in the dry season, July 2015 and August 2016, 0,03 and 0,14%. Generally speaking, that the research led to comprehend the current dynamics of the river basin environment and of the hydropower plant Salto do Rio Verdinho ́s reservoir, on their natural and man induced components that affect the water quality, thus, fulfilling the intended general aim. / O desenvolvimento da humanidade, sempre esteve ligado aos usos dos recursos hídricos. E na atualidade esses recursos, vem sendo explorado com mais intensidade, especialmente para a geração de energia elétrica, a partir da implantação de inúmeras hidrelétricas no Brasil e sobretudo muitas no Bioma Cerrado, que detém grande riqueza de recursos hídricos. Na perspectiva, de estudos necessários em ambiente de reservatório artificial após a sua implantação, o objeto do estudo selecionado foi a bacia hidrográfica e o reservatório da usina hidrelétrica (UHE) Salto do Rio Verdinho, localizada no trecho inferior da bacia hidrográfica do Rio Verde, próximo a jusante no Rio Paranaíba, afluente do Rio Paraná. Assim, o curso fluvial do Rio Verde é o limite territorial dos municípios de Caçu e Itarumã, no sul do estado de Goiás. Portanto, o presente trabalho teve por objetivo geral, compreender a dinâmica de uso e ocupação das terras da bacia e do reservatório da UHE Salto do Rio Verdinho em relação a qualidade das suas águas. Diante disso, foram realizadas avaliações da paisagem a partir da caracterização física e da relação dos seus atributos de geologia, solos, declividade, geomorfologia e remanescentes de vegetação natural, baseado na observação de princípio estrutural da paisagem, revelando que o ambiente da região da bacia como todo pertence a formações geológicas da Era Mesozoica, com relevos aplainados, e predomínio de declividades com dissecação muito fraca entre os interflúvios. As alterações no Uso e Ocupação das Terras, foram realizadas a partir de interpretação de imagens de satélites, onde se verificou que entre 2005 a 2015, o uso predominante são destinadas às áreas de pastagens com 546 km2, e a segunda classe de maior uso, foram de áreas destinadas para culturas temporárias com 237,4 km2. A análise da qualidade das águas do reservatório, foram realizadas segundo a Resolução no 357 de 2005 do CONAMA, sendo classificada como de péssima qualidade, devido aos elevados valores do nitrito e do fósforo nas águas do reservatório, que permitiram enquadra- las na classe 4. As variáveis TDS e CE, Temp e TDS, Temp e CE apresentaram correlações significativas. Os Componentes Oticamente Ativos (Clorofila, Concentração de Sedimentos em Suspensão, Transparência da água e Turbidez) na água que interferem nos espectros eletromagnéticos, apresentaram correlações com às medidas das reflectâncias nas faixas de 716 nm e 720 nm no mês de janeiro de 2015, enquanto que em fevereiro de 2016 as variáveis se correlacionaram melhores com as faixas de 647 nm, 697 nm e 704 nm, indicando que essas faixas compreendem ao comprimento de onda de luz vermelha. As reflectâncias dos meses chuvosos, de janeiro de 2015 e fevereiro de 2016, registraram valores entre 0,04 e 0,23%, já nos períodos secos registraram valores entre 0,03 e 0,14%, para os meses de julho de 2015 e agosto de 2016. De modo geral, a pesquisa, permitiu compreender a dinâmica atual do ambiente da bacia e do reservatório da UHE Salto do Rio Verdinho, sobre suas componentes naturais e antrópicas que afetam a qualidade das águas, assim, atingindo o objetivo geral proposto.

A fototerapia é um procedimento estabelecido há mais de 50 anos no tratamento da icterícia em recém-nascidos. No entanto ainda não há um método padronizado de quantificação da dose fototerápica nos estudos clínicos publicados, dificultando a comparação de estudos prévios sobre a eficácia da fototerapia, bem como o estabelecimento de doses seguras e previsíveis. A dose fototerápica depende, dentre outros fatores, da irradiância média útil entregue pelas unidades fototerápicas. Mas não há procedimentos padronizados tanto na quantificação da irradiância útil ao tratamento, quanto na estimação da irradiância média útil em fontes fototerápicas. Por isso, têm sido relatadas grandes variações nas medições de uma mesma fonte usando os radiômetros disponíveis no mercado, como conseqüência da vasta diversidade de responsividades espectrais dos instrumentos. Um objetivo deste trabalho foi adaptar e aplicar os princípios da radiometria ultravioleta de banda larga na quantificação da irradiância disponível em fontes fototerápicas, estabelecendo procedimentos que permitem comparar irradiâncias medidas em diversas fontes, usando radiômetros com diferentes responsividades espectrais. Outro objetivo foi caracterizar amostras de fontes comumente usadas atualmente, focando o problema da estimação da irradiância média útil em unidades de fototerapia, propondo um método de estimação da irradiância média útil em fontes com foco dirigido. Os resultados experimentais obtidos nos permitem concluir que não somente é necessário padronizar a radiometria fototerápica, como também o método de estimação da irradiância média útil. / Phototherapy is a procedure established more than 50 years ago in the treatment of the newborn jaundice. However there is no a standard method to quantify the phototherapeutic dose in published clinical studies, hindering the comparison of previous studies on phototherapeutic effectiveness, as well as the establishment of safe and predictable doses. The phototherapeutic dose depends, among other factors, on the effective mean irradiance produced by the phototherapeutic unit. There are no standard procedures, however, neither to quantify the effective irradiance, nor to estimate the mean effective irradiance. As a consequence, large measurement variations in a same phototherapeutic unit are observed using different commercially available radiometers, as a consequence of the vast diversity of spectral responsivities of the instruments. An objective of this work was to adapt and to apply the bases of the wideband ultraviolet radiometry to quantify the available irradiance from phototherapeutic units, establishing procedures that allow us to compare measured irradiances from different sources, using radiometers presenting different spectral responsivities. Another objective was to characterize samples of phototherapeutic units commonly used, focusing the problem of the estimation of the effective mean irradiance from phototherapeutic units, proposing a method to estimate of the effective irradiance from focused sources. The experimental results allow us to conclude that it is not only necessary to standardize the phototherapeutic radiometry, but also the method of estimation of the effective mean irradiance.

No description available.

Photothermal Radiometry is a common thermal property measurement technique which is used to measure the properties of layered materials. Photothermal Radiometry uses a modulated laser to heat a sample, in which the thermal response can be used to determine the thermal properties of layers in the sample. The motivation for this work is to provide a better understanding of the accuracy and the repeatability of the Photothermal Radiometry measurement technique. Through this work the sensitivity of results to input uncertainties will be determined. Additionally, using numerical simulations the overall uncertainty on a theoretical measurement will be determined. The repeatability of Photothermal Radiometry measurements is tested with the use of a proton irradiated zirconium carbide sample. Due to the proton irradiation this sample contains two layers with a thermal resistance between the layers. This sample has been independently measured by three different researchers, in three different countries and the results are compared to determine the repeatability of Photothermal Radiometry measurements. Finally, from sensitivity and uncertainty analysis experimental procedures and suggestions are provided to reduce the uncertainty in experimentally measured results.

No description available.

The ability to observe temperature variations inside the human body may help in detecting the presence of medical anomalies. Abnormal changes in physiological parameters (such as metabolic and blood perfusion rates) cause localized tissue temperature change. If the anatomical information of an observed tissue region is known, then a nominal temperature profile can be created using the nominal physiological parameters. Temperature-varying radiation emitted from the human body can be captured using microwave radiometry and compared to the expected radiation from nominal temperature profiles to detect anomalies. Microwave radiometry is a passive system with the ability to capture radiation from tissue up to several centimeters deep into the body. Our proposed method is to use microwave radiometry in conjunction with another imaging modality (such as ultrasound) that can provide the anatomical information needed to generate nominal profiles and improve detection of temperature anomalies. An inference framework is developed for using the nominal temperature profiles and radiometric weighting functions obtained from electromagnetic simulation software, to detect and estimate the location of temperature anomalies. The effects on inference performance of random and systematic deviations from nominal tissue parameter values in normal tissue are discussed and analyzed.