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Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-04-12T20:41:07Z No. of bitstreams: 1 2012 - Juliana de Oliveira Lopes.pdf: 1518311 bytes, checksum: 21fc297e17199bf911f4cf85812c2694 (MD5) / Made available in DSpace on 2017-04-12T20:41:07Z (GMT). No. of bitstreams: 1 2012 - Juliana de Oliveira Lopes.pdf: 1518311 bytes, checksum: 21fc297e17199bf911f4cf85812c2694 (MD5) Previous issue date: 2012-04-26 / CAPES / The teak wood (Tectona grandis L. f.) from young plantations (12 years old) has some undesirable characteristics in terms of color uniformity as well as presenting a high proportion of sapwood, which is distinguished from heartwood by the lower durability and light color. In addition, teak wood has color change when exposed to ultraviolet (UV) radiation, which depreciates the product over time. Heat treatments can be applied to change, standardize and stabilise the color of the wood, thus adding more value to the final product. In this context, the objectives of this study were: (1) to determine the effect of spacing between trees on the physical properties (density and moisture content) and the original color of wood, (2) to determine the color change of wood after heat treatments, (3) to evaluate the color uniformity of the wood (pieces containing heartwood and sapwood) after heat treatments and (4) to evaluate the color stability of heat-treated wood after UV radiation in accelerated aging conditions. Nine trees from three different levels of spacing (4 x 2 m, 5 x 2 m and 6 x 2 m) were used, with three trees per spacing. Samples of 150 x 75 x 20 mm were produced and divided into three groups: I: samples with a predominance of heartwood (? 75% heartwood in relation to sapwood), II: samples with 100% of sapwood and III: samples with approximately 50% heartwood and 50% sapwood. The groups I and II were used to determine the physical properties, wood color changes before and after heat treatments and color stability after exposure to UV radiation, whereas those of group III were used to determine the color uniformity after heat treatments. Heat treatments were performed in a laboratorial electric oven from Linn Elektro Therm under two temperatures: 180 and 200?C. Color measurements were performed using the portable spectrophotometer CM 2600d in the CIE-L*a*b* space. The accelerated aging test was performed in a QUV/Spray from Q-Lab chamber. The total cycle of exposure to UV radiation was 168 hours, and color measurements were taken to every 42 hours. The spacing affected the physical properties and the original color of wood. The heat treatment affected more the density of heartwood than sapwood. Heartwood and sapwood presented an average decrease of the 52% in equilibrium moisture content after heat treatments. Heartwood and sapwood had the same lightness pattern at the different spacings. After the heat treatment, wood had a loss of lightness, becoming darker, and this was more pronounced in the treatment at 200?C. Heartwood and sapwood presented different behavior for the coordinates a* and b* depending of spacing, before and after heat treatments. There was a greater formation of red hue and loss on yellow hue of heartwood and sapwood treated at 200?C. Heat treatments caused a higher color change on sapwood than heartwood, which provided greater uniformity to the pieces of wood with heartwood and sapwood. The color of sapwood heat-treated at 180oC woods had higher stability at UV radiation, thus demonstrating the potential of heat treatment to obtain products of higher added value. / A madeira de teca (Tectona grandis L. f.) proveniente de plantios jovens (12 anos de idade) apresenta algumas caracter?sticas indesej?veis em termos de uniformidade de cor al?m de apresentar alta propor??o de alburno, o qual distingue-se do cerne pela menor durabilidade e cor clara. Al?m disso, a madeira de teca apresenta altera??o de cor quando exposta ? radia??o ultravioleta (UV), o que acaba depreciando o material ao longo do tempo. Tratamentos termorretificadores podem ser aplicados para alterar, uniformizar e estabilizar a cor da madeira, agregando assim maior valor ao produto final. Neste contexto, os objetivos deste estudo foram: (1) determinar o efeito do espa?amento entre ?rvores nas propriedades f?sicas (densidade e teor de umidade) e na cor original da madeira, (2) determinar a altera??o da cor da madeira ap?s a termorretifica??o, (3) avaliar a uniformidade da cor da madeira (pe?as contendo cerne e alburno) ap?s os tratamentos termorretificadores e (4) avaliar a estabilidade da cor da madeira termorretificada ? radia??o UV em condi??es de envelhecimento acelerado. Foram utilizadas nove ?rvores de teca provenientes de tr?s espa?amentos (4 x 2 m, 5 x 2 m e 6 x 2 m), sendo 3 ?rvores para cada espa?amento. Amostras de 150 x 75 x 20 mm foram produzidas e divididas em tr?s grupos: I: amostras com predomin?ncia de madeira do cerne (? 75% de cerne em rela??o ao alburno), II: amostras com 100% de alburno e III: amostras com aproximadamente 50% de cerne e 50% de alburno. Os grupos I e II foram utilizados para determinar as propriedades f?sicas, a varia??o da cor da madeira antes e ap?s a termorretifica??o e a estabilidade da cor ap?s ? radia??o UV, enquanto que o grupo III foi utilizado para determinar a uniformidade da cor ap?s a termorretifica??o. A termorretifica??o foi realizada em um forno mufla el?trico laboratorial Linn Elektro Therm sob duas temperaturas: 180 e 200?C. As medi??es de cor foram realizadas atrav?s do espectrofot?metro port?til CM 2600d no espa?o CIE-L*a*b*. O ensaio de envelhecimento acelerado foi realizado em uma c?mara QUV/Spray da Q-Lab. O ciclo total de exposi??o ? radia??o UV foi de 168 horas, sendo realizadas medi??es de cor ? cada 42 horas. O espa?amento afetou as propriedades f?sicas e a cor original da madeira. A termorretifica??o afetou mais a densidade do cerne que do alburno. As madeiras de cerne e alburno apresentaram uma redu??o m?dia de 52% no teor de umidade de equil?brio ap?s a termorretifica??o. O cerne e o alburno apresentaram o mesmo padr?o de luminosidade nos diferentes espa?amentos. Ap?s a termorretifica??o, a madeira teve perda de luminosidade, tornado-se mais escura, sendo isso mais acentuado para o tratamento ? 200?C. As madeiras de cerne e alburno apresentaram comportamentos diferentes para as coordenadas a* e b* dependendo do espa?amento, antes e ap?s a termorretifica??o. Ocorreu uma maior forma??o de pigmento vermelho e perda de pigmento amarelo nas madeiras de cerne e alburno tratadas ? 200?C. A termorretifica??o proporcionou uma maior altera??o ? cor do alburno, o que resultou em uma maior uniformidade ?s pe?as de madeira contendo cerne e alburno. A cor da madeira de alburno termorretificada ? 180?C apresentou maior estabilidade ? radia??o UV, mostrando assim o potencial da termorretifica??o para obten??o de produtos de maior valor agregado.

The aim of this study was to verify the color and opacity of a ceramic system (IPS e.max Ceram - Ivoclar Vivadent) and an indirect composite resin (SR Adoro Ivoclar Vivadent), with and without polishing, when stored in different media (immersed in water and red wine. Thirty-six test specimens (sp) 12mm in diameter and 2mm thick were built for each material. Immediately after ceramic sintering, and polishing of the composite, half the sp of each material were polished with a polishing system (OptraFine P Disc - Ivoclar Vivadent), washed in water and dried with gauze. The other half of the sp remained unpolished. Initial color and Percentage of Opacity were measured with a spectrophotometer (SP60 - X-Rite), using the CIE L* a* b* system. The sp of each material were divided into groups (n=9) according to the storage media (water and red wine). Color readings were performed at the time intervals of 7 and 30 days. Color alteration (ΔE) and percentage of opacity were calculated for each time interval and the data were submitted to statistical analysis (5%). When the composite, irrespective of polishing, was immersed in water, its �E increased after 30 days storage in water, whereas for IPS e.max, changes were observed only with polishing. However, after 7 days of immersion in red wine, SR Adoro with polishing presented changes, which seemed to continue increasing after 30 days, and also without polishing. IPS e.max presented greater color changes in 30 days with and without polishing in comparison with 7 days. IPS e.max showed greater opacity than SR Adoro. In SR Adoro there is variation in opacity over the course of immersion time in wine, whereas in IPS e.max, there was no change in opacity. / O objetivo deste trabalho foi verificar a cor e a opacidade de um sistema cerâmico (IPS e.max Ceram - Ivoclar Vivadent) e de um compósito de confecção indireta (SR Adoro Ivoclar Vivadent), com e sem polimento, quando armazenados em meios diferentes e por tempos distintos. Foram confeccionados 36 corpos de prova (cps) para cada material com 12 mm de diâmetro e 2 mm de espessura. Imediatamente após a sinterização da cerâmica e polimerização do compósito, a metade dos cps de cada material foi polida com um sistema de polimento (OptraFine P Disc - Ivoclar Vivadent), lavada em água e seca com gaze. A outra metade dos cps permaneceu sem polimento. Foi realizada a mensuração inicial de cor e o Percentual de Opacidade com um espectrofotômetro (SP60 - X-Rite), utilizando o sistema CIE L* a* b*. Os cps de cada material foram divididos em grupos (n=9) de acordo com os meios de armazenamento (água e vinho tinto). Leituras foram realizadas nos períodos de 7 e 30 dias. A alteração de cor (ΔE) e o Percentual de Opacidade foram calculados para cada período e os dados foram submetidos à análise estatística (5%). O compósito, independente do polimento, quando imerso em água após 30 dias de armazenamento aumentou o seu �E, enquanto que no sistema cerâmico a alteração foi observada apenas no grupo com polimento. Já em 7 dias de imersão em vinho o SR Adoro com polimento apresentou alteração, o que parece permanecer aumentando após 30 dias e também sem polimento. O IPS e.max apresentou maior alteração de cor em 30 dias com e sem polimento comparado com 7 dias. O IPS e.max demonstrou maior opacidade que o SR Adoro.

This study aimed to evaluate the translucency and value with different combinations of enamel , dentin and body of each composite regarding a standard thickness (1,5mm). Three different resin composites commercially available with a standard shade (A1), IPS Empress Direct, Charisma Diamond and Filtek Z350 XT were evaluated. A stainless steel matrix was used to prepare ninety disc-shaped specimens with 11mm diameter and 1,5mm thickness. The specimens were randomly allocated in 18 groups (n=5) according to different combinations of enamel , dentin and body presented in each resin composite evaluated. After light curing, specimens were stored in deionized water at 37º C for 24h. Three consecutive readings were performed according to the CIE L*a*b* color scale relative to the standard illuminant D65 on reflection spectrophotometer (SP60 - EX-Rite). The optical properties of translucency and value were measured by the parameters translucency (TP) and lightness in white background (L*w) and black background (L*b), respectively. The mean TP, L*w and L*b were analyzed by ANOVA (General Linear Models) and Tukey s post hoc tests (α =0.05). Scatter plots together with Spearman´s correlation coefficient were used to assess the relationship between TP and L*w and TP and L*b values. The groups had statistical significant different values (p=0.000). The resin composite Empress Direct when only a layer of enamel were employed presented the highest TP value, whereas the resin composite Filtek Z350 XT with a single layer of dentin presented the lowest TP value. A negative and strong correlation between TP and L*b and a positive and weak correlation between TP and L*w were observed. Optical properties as translucency and value rely on the material used. In general, there was statistical difference between the groups for TP and L* / Este estudo tem como objetivo analisar o comportamento óptico de diferentes resinas compostas, em distintas combinações de esmalte, dentina e corpo de cada composto em relação à espessura padrão (1,5mm) na percepção da translucidez e valor. Foram analisadas três marcas comerciais de resina composta (IPS Empress Direct, Charisma Diamond, Filtek Z350 XT) na cor A1. Uma matriz metálica foi utilizada para confeccionar noventa espécimes (1,5mm de espessura e 11mm de diâmetro). Os espécimes foram randomizados e divididos em 18 grupos (n=5) conforme as possibilidades de combinações de esmalte, dentina e corpo. Após a fotopolimerização, os espécimes foram armazenados em água deionizada por 24h a 37°C. Três leituras consecutivas foram realizadas por um espectrofotômetro de reflexão (SP 60 EX-Rite) relativo ao iluminante padrão D65 de acordo com o sistema CIE L* a* b*. As propriedades ópticas, translucidez e valor, foram mensuradas pelo parâmetro de translucidez (TP) e pela variável L* sobre fundo preto e branco respectivamente. A média dos valores do TP, L*b e L*p foram analisadas por ANOVA (Modelo Linear Geral) e testes Tukey s post hoc (α=0,05). Gráficos de dispersão juntamente com o coeficiente de correlação de Spearman entre TP e L*p e TP e L*b foram calculados. Os grupos apresentaram diferença estatística (p = 0,000). A resina composta Empress Direct somente de esmalte apresentou o maior valor de TP, enquanto Filtek Z350 XT com uma única camada de dentina apresentou o menor valor de TP. Há uma forte correlação negativa entre TP e L*p e uma fraca correlação positiva entre TP e L*b. Propriedades ópticas de translucidez e valor são dependentes do material utilizado. De maneira geral, houve diferenças entre os grupos estudados quando analisados o TP e L*.

The aim of the thesis on "Evaluation of the color of honey" was to determine why the instrument can not Lovibond Honey Colorpod 440110 to evaluate color of all types of honey and compare results of with spectrophotometric measurement methods. The work is divided into theoretical and practical part. The theoretical part is dedicated to honey, its composition and methods of evaluating color. The practical part describes the results obtained instrument Lovibond Honey Colorpod -- 440110, spectrophotometers Konica Minolta -- 3500d a FT -- NIR Antaris. In UV/VIS region not been demonstrated reason of errors of photometer. Maximum lightness had a very light honeys and the largest share of yellow had light honey. The highest values of absorbance attain dark honeys. In color space CIE L* a* b* had the largest share of red. Evaluation of the color of honey in the UV/VIS can not prove adulteration of honey always unambiguously, but there are signs by which honey can be described as suspicious. By analyzing the NIR spectrum is falsification of honey demonstrated using discriminant analysis.

It was investigated the colour reproduction on prints made in ink-jet printer. Experimentally investigated gradation characteristics of CMYK colours. It was made a 26 step strip with raster dots from 0 to 100 %. Prints were made at different printing regimes on papers with different whiteness. Zone optical densities were measured, compared with theoretical density values and gradational distortions were determined. Also were measured 100% raster strips in CIE L*a*b* coordinate system and defined the maximum reproduction of colours in ink-jet printer.

V diplomové práci je prezentovaná literární rešerše na téma termochromní pigmenty a jejich aplikace v polymerních matricích. Výzkum byl zaměřen na hlubší pochopení termochromního efektu v pigmentech na bázi molekulárních komplexů. Termochromní pigmenty byly aplikovány do polyuretanového textilního zátěru a bylo zjištěno optimální nastavení podmínek zátěru. Textilní zátěry byly podrobeny termickým zkouškám a zároveň byla pozorována jejich stálobarevnost.

Tooth-whitening or tooth-bleaching has become an integral part of modern dental practice. Today, a large number of whitening products are available on the market which are commonly categorized into dentist-supervised home bleaching, in-office bleaching and over-the-counter bleaching products according to their mode of application. This thesis looks into safety and efficacy of various tooth-whitening products and methods.

Tooth-whitening or tooth-bleaching has become an integral part of modern dental practice. Today, a large number of whitening products are available on the market which are commonly categorized into dentist-supervised home bleaching, in-office bleaching and over-the-counter bleaching products according to their mode of application. This thesis looks into safety and efficacy of various tooth-whitening products and methods.

Philosophiae Doctor - PhD / Tooth-whitening or tooth-bleaching has become an integral part of modern dental practice. Today, a large number of whitening products are available on the market which are commonly categorized into dentist-supervised home bleaching, in-office bleaching and over-the-counter bleaching products according to their mode of application. This thesis looks into safety and efficacy of various tooth-whitening products and methods. / South Africa