Thesis (M.S.)--Rochester Institute of Technology, 1992. / Typescript. Includes bibliographical references (leaves [152]-164).

Thesis (M.S.)--Rochester Institute of Technology, 2009. / Typescript. Includes bibliographical references (leaves 55-57).

Thesis (M.S.)--University of Michigan, 2001. / Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 2001. / Includes bibliographical references.

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O propósito deste trabalho foi avaliar, in-vitro, a alteração de cor da cerâmica de dissilicato de lítio, após o envelhecimento artificial acelerado (EAA), variando-se os seguintes aspectos: processo de confecção (cerâmica monolítica e com infraestrutura coberta por cerâmica de revestimento), espessuras de 1,5 e 2,0mm e substratos de resina e liga metálica, com e sem cimento. Para isso foram confeccionadas 40 pastilhas de cerâmica IPS e.max Press, que foram divididas em 2 grupos (n=20): LT (cerâmica de baixa translucidez na cor A2) e HO (cerâmica de alta opacidade). Neste grupo as pastilhas foram confeccionadas com 0,5mm de espessura e, posteriormente, revestidas com a cerâmica IPS e.max Ceram na cor A2 e com espessuras de 1,0 e 1,5mm. Foram utilizados substratos em resina composta (n=20) e em liga metálica (cobre-alumínio) (n=20). Para a cimentação foi utilizado o cimento de polimerização dual Variolink II, na cor translúcida. A leitura da cor foi realizada em um espectrofotômetro (Minolta CM2600d), equipado com fonte de luz padrão D65 (luz do dia). A cor determinada no aparelho é expressa em coordenadas CIE L* a* b* e os valores correspondentes foram utilizados para calcular o E. Foram feitas as seguintes comparações: discos de cerâmica antes do EAA vs discos de cerâmica cimentadas sobre os substratos antes do EAA; discos de cerâmica cimentadas sobre os substratos antes do EAA vs discos de cerâmica cimentadas sobre os substratos após o EAA; discos de cerâmica antes do EAA vs discos de cerâmica cimentadas sobre os substratos após o EAA; discos de cerâmica antes do EAA vs discos de cerâmica após o EAA. Os dados foram submetidos a análise estatística (ANOVA) a 3 critérios e (ANOVA) a 2 critérios e testes de Tukey, p<0,05). Os resultados mostraram que: 1. os grupos somente de discos de cerâmica vs discos de cerâmica com 1,5 e 2,0mm de espessuras, cimentadas em substratos de resina e liga metálica, antes do EAA. O menor valor encontrado de E (E=3,6) foi com o grupo de discos da cerâmica HOA2 com 2mm de espessura cimentados em substrato de metal, seguido pelo grupo da mesma cerâmica com 1,5mm de espessura cimentada em substrato de resina. O maior valor encontrado (E=10,0) foi com os discos de cerâmica LTA2 com 1,5 e 2mm de espessuras e cimentados em substrato de metal; 2. os grupos com discos de cerâmicas com 1,5 e 2,0mm de espessuras e cimentados em substratos de resina e liga metálica antes do EAA vs o mesmo grupo após EAA. Os grupos de discos com a cerâmica HOA2 com 2mm de espessura cimentados em substrato de metal teve menor alteração de cor (E=1,1) e a maior alteração de cor ocorreu com o grupo da cerâmica LTA2 com 2mm de espessura cimentada em substrato de metal (E=2,1); 3. os grupos somente com discos de cerâmica antes do EAA vs grupos de cerâmicas com discos de 1,5 e 2,0mm de espessuras e cimentados em substratos de resina e liga metálica após o EAA. O menor valor encontrado (E=3,7) foi com a cerâmica HOA2 com revestimento e 2mm de espessura cimentada em substrato de metal. O maior valor encontrado (E=10,0) foi o da cerâmica LTA2 com 1,5 e 2mm de espessuras cimentadas em substrato de metal; 4. os grupos discos de cerâmica, antes e após o processo de EAA O grupo que teve menor alteração de cor foi o da cerâmica HOA2 com 1,5mm (E=0,6). O grupo que teve maior alteração de cor foi o da cerâmica LTA2 com 2mm (E=2,2). Concluiu-se que o EAA causou alteração na cor final das cerâmicas de dissilicato de lítio, levando-se em conta as variáveis pesquisadas. / The purpose of this in vitro study was to evaluate the color changing of the lithium disilicate ceramic discs after accelerated artificial aging (AAA) varying the following aspects: manufacturing process (monolithic ceramic and infrastructure with ceramic covering), thickness of the ceramic (1.5 and 2.0 mm) and abutment substrate (composite resin and alloy), with and without cement. Forty ceramic discs were fabricated with ceramic IPS e.max Press and divided into two groups (n = 20): LT (low translucency, shade A2) and HO (high opacity). In the HO group, the discs were fabricated with a thickness of 0.5 mm of the IPS e.max Ceram combined with a thickness of 1 or 1.5mm of veneering ceramic, shade A2. The abutments substrates were fabricated with composite resin (n = 20) and metallic alloy (n = 20). The resin cement used was Variolink II translucent color. Color was measured with a spectrophotometer and expressed in CIE L * a * b * coordinates. Color differences (E) were calculated. The data were analyzed with ANOVA and the Tukey HSD test (p <0.05).The results showed that 1.in the groups of ceramic discs vs. ceramic discs with 1.5 and 2.0mm thickness, cemented on resin substrates and metal alloy, before AAA, the lowest value of E (E = 3,6) was obtained for HOA2 ceramic discs with 2mm thickness cemented in metal substrate, followed by ceramic discs with 1.5mm thickness cemented in substrate of resin. The highest value (E = 10.0) was observed for ceramic discs LTA2 with 1.5 and 2mm thickness and cemented in metal substrate; 2. In the groups with ceramic discs with 1.5 and 2.0mm thickness and cemented on resin and metal substrates prior to AAA vs the same group after AAA, the HOA2 ceramic discs with 2mm thickness cemented on a metal substrate had the smallest color change (E = 1,1) and the largest occurred for LTA2 with 2mm thickness and cemented in metallic substrate (E = 2.1); 3. In the groups of ceramic discs before AAA vs groups of ceramic with discs of 1.5 and 2.0mm of thickness and cemented on resin substrates and metal alloy after AAA, the lowest value (E = 3,7) was obtained for HOA2 veneering ceramic 2mm thickness cemented on a metal substrate. The highest value found (E = 10.0) was for LTA2 ceramic with 1.5 and 2mm thickness cemented on a metal substrate; 4. comparing the groups of ceramic discs before and after the AAA process, the lowest color change was obtained for HOA2 ceramic with 1.5mm (E = 0.6) and the greatest color change was fore LTA2 ceramic with 2mm (E = 2.2). It was concluded that the AAA caused alteration in the final color of the lithium disilicate ceramics, taking into account the variables studied.

The thesis presents the evaluation of polysulfone sorbents for solid phase extraction (SPE) and the development of colorimetric probes for pesticides analysis in water. Through electrospraying and electrospinning techniques, different morphologies of sorbents (particles, beaded fibers and bead-free fibers) were fabricated. The sorbents were morphologically characterized by scanning electron microscopy. Adsorption capacities of sorbents were evaluated by conducting recoveries studies for model pesticides; atrazine, chlorpyrifos and DDT using batch and column SPE modes. Better recovery results were achieved by employing the batch mode of fibers, as values ranged from 98 to 105percent. Further sorbent evaluation was conducted using breakthrough experiments and static experiments. The breakthrough studies indicated that 1700 μL was the sample volume that could be percolated with no breakthrough of the analyte that correspond to a concentration of 150 mg/g of sorbent that can be extracted without any loss of analyte. From static studies, quantities of each model compound adsorbed into the fiber at the equilibrium time were evaluated. The adsorbed atrazine was 65, chlorpyrifos 250 and DDT 400 mg/g of sorbent. Kinetic studies suggested retention mechanism following pseudo first and second order model observed by high correlation coefficients (> 0. 96), demonstrating the fiber affinity to retain both polar and non-polar compounds opening a possibility to be used as sorbent for sample preparation of different classes of pesticides in water. For the second part of the study simple strategies for colorimetric sensing based on silver nanoparticles and polivinylpyrrolidone capped nanoparticles were developed, respectively for atrazine and chlorpyrifos detection. The limits of detection of the methods were 3.32 and 0.88 mg/L for atrazine and chlorpyrifos respectively. The applicability of the probe in real samples was demonstrated by the recoveries studies of tap water varying from 94 to 104 percent. The versatility of the probe was demonstrated by affording a simple, rapid and selective detection of atrazine and chlorpyrifos in the presence of other pesticides by direct analysis without employing any sample handling steps. Attempt to incorporate the probes in a solid support was achieved by using nylon 6 as solid support polymer proving to be fast and useful for on-site detection.

Les nouvelles techniques de compression vidéo doivent intégrer un haut niveau d'adaptabilité, à la fois en terme de bande passante réseau, de scalabilité des formats (taille d'images, espace de couleur…) et de compatibilité avec l'existant. Dans ce contexte, cette thèse regroupe des études menées en lien avec le standard HEVC. Dans une première partie, plusieurs adaptations qui exploitent les propriétés du signal et qui sont mises en place lors de la création du bit-stream sont explorées. L'étude d'un nouveau partitionnement des images pour mieux s'ajuster aux frontières réelles du mouvement permet des gains significatifs. Ce principe est étendu à la modélisation long-terme du mouvement à l'aide de trajectoires. Nous montrons que l'on peut aussi exploiter la corrélation inter-composantes des images et compenser les variations de luminance inter-images pour augmenter l'efficacité de la compression. Dans une seconde partie, des adaptations réalisées sur des flux vidéo compressés existants et qui s'appuient sur des propriétés de flexibilité intrinsèque de certains bit-streams sont investiguées. En particulier, un nouveau type de codage scalable qui supporte des espaces de couleur différents est proposé. De ces travaux, nous dérivons des metadata et un modèle associé pour opérer un remapping couleur générique des images. Le stream-switching est aussi exploré comme une application particulière du codage scalable. Plusieurs de ces techniques ont été proposées à MPEG. Certaines ont été adoptées dans le standard HEVC et aussi dans la nouvelle norme UHD Blu-ray Disc. Nous avons investigué des méthodes variées pour adapter le codage de la vidéo aux différentes conditions de distribution et aux spécificités de certains contenus. Suivant les scénarios, on peut sélectionner et combiner plusieurs d'entre elles pour répondre au mieux aux besoins des applications. / The new video codecs should be designed with an high level of adaptability in terms of network bandwidth, format scalability (size, color space…) and backward compatibility. This thesis was made in this context and within the scope of the HEVC standard development. In a first part, several Video Coding adaptations that exploit the signal properties and which take place at the bit-stream creation are explored. The study of improved frame partitioning for inter prediction allows better fitting the actual motion frontiers and shows significant gains. This principle is further extended to long-term motion modeling with trajectories. We also show how the cross-component correlation statistics and the luminance change between pictures can be exploited to increase the coding efficiency. In a second part, post-creation stream adaptations relying on intrinsic stream flexibility are investigated. In particular, a new color gamut scalability scheme addressing color space adaptation is proposed. From this work, we derive color remapping metadata and an associated model to provide low complexity and general purpose color remapping feature. We also explore the adaptive resolution coding and how to extend scalable codec to stream-switching applications. Several of the described techniques have been proposed to MPEG. Some of them have been adopted in the HEVC standard and in the UHD Blu-ray Disc. Various techniques for adapting the video compression to the content characteristics and to the distribution use cases have been considered. They can be selected or combined together depending on the applications requirements.

<p>Microscale environments provide significant resolution and distortion challenges with respect to measurement techniques; however, with improvements to existing techniques, it is possible to gather relevant data to better understand the thermal and fluidic mechanisms at such small scales in evaporating droplets.</p> <p> </p> <p>Infrared thermography provides several unique challenges at small scales. A primary issue is that the low native resolution of traditional infrared cameras significantly hamper the collection of details of microscale features. Furthermore, surfaces exhibiting vastly different emissivities, results in inaccurate temperature measurements that can only be corrected with irradiance-based emissivity maps of the surface; however, due to the resolution limitations of infrared thermography, these emissivity maps can also display significant errors. These issues are overcome through the use of multi-frame super-resolution. The enhanced resolution allows for better capture of microscale features, therefore, enhancing the emissivity map. A quantitative error analysis of the system is conducted to quantify the feature size resolution improvement as well as the smoothing effect of super-resolution reconstruction. Furthermore, a sensitivity analysis is conducted to quantify the impact of registration uncertainty on the accuracy of the reconstruction. Finally, the improved emissivity map from super-resolution is demonstrated to show the increased accuracy over low-resolution mapping.</p> <p> </p> <p>When applied to water droplets, particularly on nonwetting surfaces, infrared thermography is confounded by the presence of nonuniform reflectivities due to the spherical curvature of the liquid-air interface. Thus, when measuring the temperature along the vertical axis of a water droplet, it is necessary to correct the reflection. Using a controlled background environment, in conjunction with the Fresnel equations, it is possible to correct the reflective effects on the interface and calculate the actual temperature profile. This allows for a better understanding of the governing mechanisms that determine the thermal transport within the droplet. While thermal conduction is the primary transport mechanism along the vertical axis of the droplet, it is determined that the temperature drop is partially dampened by the convective transport from the ambient air to the liquid interface. From this understanding revealed by the measurements, the vapor-diffusion-based model for evaporation was enhanced to better predict evaporation rates.</p> <p> </p> <p>Further exploration into the mechanisms behind droplet evaporation on nonwetting surfaces requires accurate knowledge of the internal flow behavior. In addition, the influence of the working fluid can have a significant impact on the governing mechanisms driving the flow and the magnitude of the flowrate. While water droplet evaporation has been shown to be governed by buoyancy-driven convection on nonwetting substrates, similar studies on organic liquid droplets are lacking. Particle image velocimetry is effective at generating a velocity flow field, but droplets introduce distortion due to the refraction from the spherical interface of the droplet. As such, velocity correction using a ray-tracing approach was conducted to correct the velocity magnitudes and direction. With the velocity measurements, the flow was determined to be surface-tension-driven and showed speeds that are an order of magnitude higher than those seen in buoyancy-driven flow in water droplets. This resulted in the discovery that advection plays a significant role in the transport within the droplet. As such, the vapor-diffusion-governed evaporation model was adjusted to show a dramatic improvement at predicting the temperature gradient along the vertical axis of the droplet.</p> <p> </p> <p>Armed with the knowledge of flow behavior inside droplets, it is expected that droplets with aqueous solutions should exhibit buoyancy-driven convection. The final part of this work, therefore, leverages this phenomenon to enhance mixing during reactions. Colorimetry is a technique that is widely utilized to measure the concentration of a desired sample within some liquid; the sample reacts with a reagent dye the color change is measured, usually through absorbance measurements. In particular, the Bradford assay is used to measure protein concentration by reacting the protein to a Coomassie^TM Brilliant Blue G-250. The absorbance of the dye increases, most significantly at the 590 nm wavelength, allowing for precise quantitation of the amount of protein in the solution. A droplet-based reaction chamber with buoyancy-enhanced mixing has the potential to speed up the measurement process by removing the need for a separate pre-mixing step. Furthermore, the reduced volume makes the process more efficient in terms of reactant usage. Experimental results of premixed solutions of protein sample and reagent dye show that the absorbance measurement through a droplet tracks strongly with the protein concentration. When the protein sample and dye reagent are mixed <i>in situ</i>, the complex interaction between the reactants, the mixing, and the adsorption of protein onto the substrate creates a unique temporal evolution in the measured absorbance of the droplet. The characteristic peaks and valleys of this evolution track strongly with concentration and provide the framework for measurement of concentration in a droplet-based system.</p> <p> </p> <p>This thesis extends knowledge about droplet thermal and fluidic behavior through enhanced measurement techniques. This knowledge is then leveraged in a novel application to create a simple, buoyancy-driven colorimetric reaction setup. Overall, this study contributes to the field of miniaturized, efficient reaction and measurement devices.</p>

A incidência de doenças crônicas atinge índices epidêmicos, sendo responsável por mais de 60% da mortalidade mundial. Medidas preventivas são adotadas e, entre elas, uma alimentação balanceada. Nesta inclui-se o consumo de frutos e vegetais, especialmente os de coloração vermelha e laranja, ricos em carotenoides, fitonutrientes que muitas vezes assumem papel de antioxidantes, prevenindo a incidência destas doenças. No presente trabalho foram obtidas linhagens quase isogênicas (NILs) de tomateiro contendo os alelos at, B, Del, gf, og, r, t e y, os quais afetam a composição de carotenoides. Tais linhagens constituem uma importante ferramenta para estudos de nutracêutica, como os testes de biodisponibilidade de diferentes tipos de carotenoides no plasma sanguíneo, após ingestão, o que foi testado no presente trabalho através do emprego de HPLC e ratos da linhagem Wistar. Além disso, frente às diferentes ofertas de cores e composições metabólicas de tomates disponíveis no mercado, as NILs permitiram o ajuste de parâmetros de colorimetria como um método rápido para identificar os principais mutantes da via de biossíntese de carotenoides presentes em linhagens comerciais. Ressalta-se que, muitas vezes as cores podem enganar e não trazer vantagens nutricionais, como é o caso do consumo de linhagens comerciais contendo a mutação yellow flesh (r). Por fim, as NILs foram utilizadas para verificar se as mutações alterando a composição de carotenoides possuíam alguma penalidade em termos de produtividade ou outros parâmetros de qualidade de fruto (Teor de Sólidos Solúveis, acidez). Os resultados mostraram-se de aplicabilidade e geraram um banco de dados passível de expansão, para novos mutantes que alterem a cor do tomate e fazendo uso de outros backgrounds. Tais dados podem ser usados tanto para programas de melhoramento visando a qualidade nutricional, quanto para o comércio atacado, beneficiando o consumidor final. / The incidence of chronic disease reaches epidemic levels, accounting for over 60% of global mortality. Preventive measures are adopted, and among them, a balanced diet. This includes the fruits and vegetables consumption, especially the red and orange ones, rich in carotenoids, phytonutrients which often assumes the role of antioxidants preventing these diseases incidence. In this study, tomato near isogenic lines (NILS) containing the alleles B, Del, gf, og, r, t and y, were obtained, affecting the carotenoid fruit content. Such lines are an important tool for nutraceutical studies, like different carotenoids bioavailability tests in blood plasma after ingestion, which was tested in this work by HPLC employment and Wistar rats. Moreover, in the face of different colors and metabolic contents offerings of tomatoes available at the market, NILs allowed the adjustment of colorimetric parameters as a fast way to identify carotenoids biosynthetic pathway key mutants present in commercial strains. It is highlighted that many times colors can mislead and not bring nutritional benefits, like the consumption of commercial strains containing the mutation yellow flesh (r). At the end, NILs were used to verify if the carotenoid content mutations had some penalty in terms of productivity or other fruit quality parameters (Soluble Solids Content, acidity). The results showed relevant and generated a database capable of expansion to new fruit color tomato mutants even in other genetic backgrounds. Such data can be used both for nutritional quality breeding programs, both for the wholesale trade, benefiting the end user.