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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Degree of Whiteness and Maturity Among World Cotton Cultivars

Gregory, Kendra 2012 May 1900 (has links)
Increased US export of cotton and global competition necessitates that plant breeders continue to improve fiber properties of upland cotton, Gossypium hirsutum (L.). Cotton cultivars having whiter fibers and more mature fibers are desirable due to decreased processing costs. TAM B182-33 ELS (Extra Long Staple) germplasm line of upland cotton, and Tamcot CAMD-E, a short staple obsolete cultivar were crossed with 36 cultivars representing unique germplasm pools from China (12 cultivars), west and central Africa (7 cultivars), south Africa (10 cultivars), and the United States (7 cultivars) that represent distinct germplasm pools. Parents and F1s were grown in College Station, TX, in a Line x Tester design during the summers of 2010 and 2011. Seedcotton was harvested by hand (to avoid the presence of thrash particles in the lint that could bias the color measurements), deburred and allowed to dry in limited light. Cotton samples were ginned on a laboratory saw gin, separated into 2.00 gram subsamples, and color measurements were taken using a Konica-Minolta CR-310 reflectance colorimeter. Absolute color measurements were obtained in two color systems (tristimulus XYZ and CIE L*a*b*). At the Fiber and Biopolymer Research Institute (FBRI) in Lubbock, TX, 50.0 mg samples of the 38 parents and F1s were used to determine maturity ratio (MR), ribbon width (RbWth) and micronaire (Mic) on a Cottonscope. The fibers were cut into 2.0 mm snippets and immersed in an aqueous solution containing a surfactant and NaCl. Approximately, 20,000 snippets per entry were analyzed for MR, RbWth and Mic in the Cottonscope using polarized light. General and specific combining abilities for all the variables were calculated from the data collected. Despite the evident genetic variation from this study for the degree of fiber whiteness, the difficulties in the phenotypic screening of this trait and its importance relative to other fiber traits are problematic. At this time, it is not advisable to begin a cotton breeding program based upon degree of fiber whiteness. Genetic variation also existed for MR, RbWth and Mic among the distinct germplasm pools utilized in this study, but it is not advisable to begin a breeding program based on RbWth or Mic. However, a cotton breeding program to improve MR would be feasible, especially with fast and repeatable measurements from the Cottonscope.
2

Analysis of coronal discoloration from commonly used obturation materials.

Elkhazin, Mohamed M. A. January 2007 (has links)
<p>The objective of this study was to assess coronal discoloration due to four commonly used endodontic sealers with gutta-percha, using spectrophotometric analysis. Extracted human teeth were obturated with the experimental sealers and GP. The sealers that were tested included AH Plus, EndoRez, and Kerr Pulp Canal Sealer. The teeth were maintained in a moist environment at 37 C. Immediate pretreatment readings of the crowns of the extracted teeth with a spectrometer were used as baseline data. Subsequent readings were taken every two weeks for two months. Results were analysed using Wilcoxson Signed Rank sum test and Kruskal Wallis test.</p>
3

Analysis of coronal discoloration from commonly used obturation materials.

Elkhazin, Mohamed M. A. January 2007 (has links)
<p>The objective of this study was to assess coronal discoloration due to four commonly used endodontic sealers with gutta-percha, using spectrophotometric analysis. Extracted human teeth were obturated with the experimental sealers and GP. The sealers that were tested included AH Plus, EndoRez, and Kerr Pulp Canal Sealer. The teeth were maintained in a moist environment at 37 C. Immediate pretreatment readings of the crowns of the extracted teeth with a spectrometer were used as baseline data. Subsequent readings were taken every two weeks for two months. Results were analysed using Wilcoxson Signed Rank sum test and Kruskal Wallis test.</p>
4

Analysis of coronal discoloration from commonly used obturation materials

Elkhazin, Mohamed M. A. January 2007 (has links)
Magister Scientiae Dentium - MSc(Dent) / The objective of this study was to assess coronal discoloration due to four commonly used endodontic sealers with gutta-percha, using spectrophotometric analysis. Extracted human teeth were obturated with the experimental sealers and GP. The sealers that were tested included AH Plus, EndoRez, and Kerr Pulp Canal Sealer. The teeth were maintained in a moist environment at 37 C. Immediate pretreatment readings of the crowns of the extracted teeth with a spectrometer were used as baseline data. Subsequent readings were taken every two weeks for two months. Results were analysed using Wilcoxson Signed Rank sum test and Kruskal Wallis test. / South Africa
5

Automated facial metrology

O'Mara, David Thomas John January 2002 (has links)
Automated facial metrology is the science of objective and automatic measurement of the human face. There are many reasons for measuring the human face. Psychologists are interested in determining how humans perceive beauty, and how this is related to facial symmetry [158]. Biologists are interested in the relationship between symmetry and biological fitness [124]. Anthropologists, surgeons, forensic experts, and security professionals can also benefit from automated facial metrology [32, 101, 114]. This thesis investigates the concept of automated facial metrology, presenting original techniques for segmenting 3D range and colour images of the human head, measuring the bilateral symmetry of n-dimensional point data (with particular emphasis on measuring the human head), and extracting the 2D profile of the face from 3D data representing the head. Two facial profile analysis techniques are also presented that are incremental improvements over existing techniques. Extensive literature reviews of skin colour modelling, symmetry detection, symmetry measurement, and facial profile analysis are also included in this thesis. It was discovered during this research that bilateral symmetry detection using principal axes is not appropriate for detecting the mid-line of the human face. An original mid-line detection technique that does not use symmetry, and is superior to the symmetry-based technique, was developed as a direct result of this discovery. There is disagreement among researchers about the effect of ethnicity on skin colour. Some researchers claim that people from different ethnic groups have the same skin chromaticity (hue, saturation) [87, 129, 206], while other researchers claim that different ethnic groups have different skin colours [208, 209]. It is shown in this thesis that people from apparently different ethnic groups can have skin chromaticity that is within the same Gaussian distribution. The chromaticity-based skin colour model used in this thesis has been chosen from the many models previously used by other researchers, and its applicability to skin colour modelling has been justified. It is proven in this thesis that the Mahalanobis distance to the skin colour distribution is Gaussian in both the chromatic and normalised rg colour spaces. Most facial profile analysis techniques use either tangency or curvature to locate anthropometric features along the profile. Techniques based on both approaches have been implemented and compared. Neither approach is clearly superior to the other, but the results indicate that a hybrid technique, combining both approaches, could provide significant improvements. The areas of research most relevant to facial metrology are reviewed in this thesis and original contributions are made to the body of knowledge in each area. The techniques, results, literature reviews, and suggestions presented in this thesis provide a solid foundation for further research and hopefully bring the goal of automated facial metrology a little closer to being achieved.
6

Analyse de l'illumination et des propriétés de réflectance en utilisant des collections d'images / Illumination and Photometric Properties using Photo Collections

Diaz, Mauricio 26 October 2011 (has links)
L'utilisation de collections d'images pour les applications de vision par ordinateur devient de plus en plus commune des nos jours. L'objectif principal de cette thèse est d'exploiter et d'extraire des informations importantes d'images de scènes d'extérieur a partir de ce type de collections : l'illumination présente au moment de la prise, les propriétés de reflectance des matériaux composant les objets dans la scène et les propriétés radiométriques des appareils photo utilisés. Pour atteindre notre objectif, cette thèse est composée de deux parties principales. Dans un premier temps nous allons réaliser une analyse de différentes représentations du ciel et une comparaison des images basée sur l'apparence de celui-ci. Une grande partie de l'information visuelle perçue dans les images d'extérieures est due a l'illumination en provenance du ciel. Ce facteur est représenté par les rayons du soleil réfléchis et réfractés dans l'atmosphère en créant une illumination globale de l'environnement. En même temps cet environnement détermine la façon de percevoir les objets du monde réel. Etant donné l'importance du ciel comme source d'illumination, nous formulons un processus générique en trois temps, segmentation, modélisation et comparaison des pixels du ciel, pour trouver des images similaires en se basant sur leurs apparences. Différentes méthodes sont adoptées dans les phases de modélisation et de comparaison. La performance des algorithmes est validée en trouvant des images similaires dans de grandes collections de photos. La deuxième partie de cette thèse consiste a exploiter l'information géométrique additionnelle pour en déduire les caractéristiques photométriques de la scène. A partir d'une structure 3D récupérée en utilisant des méthodes disponibles, nous analysons le processus de formation de l'image a partir de modèles simples, puis nous estimons les paramètres qui les régissent. Les collections de photos sont généralement capturées par différents appareils photos, d'où l'importance d'insister sur leur calibrage radiométrique. Notre formulation estime cet étalonnage pour tous les appareils photos en même temps, en utilisant une connaissance a priori sur l'espace des fonctions de réponse des caméras possibles. Nous proposons ensuite, un cadre d'estimation conjoint pour calculer une représentation de l'illumination globale dans chaque image, l'albedo de la surface qui compose la structure 3D et le calibrage radiométrique pour tous les appareils photos. / The main objective of this thesis is to exploit the photometric information avail- able in large photo collections of outdoor scenes to infer characteristics of the illumination, the objects and the cameras. To achieve this goal two problems are addressed. In a preliminary work, we explore opti- mal representations for the sky and compare images based on its appearance. Much of the information perceived in outdoor scenes is due to the illumination coming from the sky. The solar beams are reflected and refracted in the atmosphere, creating a global illumination ambiance. In turn, this environment determines the way that we perceive objects in the real world. Given the importance of the sky as an illumination source, we formulate a generic 3–step process in order to compare images based on its appearance. These three stages are: segmentation, modeling and comparing of the sky pixels. Different approaches are adopted for the modeling and comparing phases. Performance of the algorithms is validated by finding similar images in large photo collections. A second part of the thesis aims to exploit additional geometric information in order to deduce the photometric characteristics of the scene. From a 3D structure recovered using available multi–view stereo methods, we trace back the image formation process and estimate the models for the components involved on it. Since photo collections are usually acquired with different cameras, our formulation emphasizes the estimation of the radiometric calibration for all the cameras at the same time, using a strong prior on the possible space of camera response functions. Then, in a joint estimation framework, we also propose a robust computation of the global illumination for each image, the surface albedo for the 3D structure and the radiometric calibration for all the cameras.
7

Avaliação de Metodologia para Controle e Medição de Cor em Efluentes Têxteis. / Methodology for Assessment and Control Color Measurement in Waste Textiles.

Gil Leonardo Aliprandi Lucido 01 December 2010 (has links)
Os processos de beneficiamento têxtil, como o alvejamento, a purga, o tingimento e as lavagens são reconhecidamente impactantes ao meio ambiente, tanto do ponto de vista de consumo de água, quanto da geração de efluentes. Os efluentes têxteis oriundos dos processos de beneficiamento se caracterizam por apresentarem elevadas concentrações de substâncias emulsificantes, íons cloreto, sólidos e matéria orgânica, além de alta toxicidade. Mas sem dúvida, o maior problema desses efluentes deve-se a presença de corantes e pigmentos. Alguns parâmetros físico-químicos importantes no controle da poluição hídrica são de difícil medição e consequente monitoramento, principalmente pela ausência de legislação que expresse de maneira clara e objetiva os limites destes parâmetros. Este fato permite avaliações dúbias e contestações aos órgãos ambientais. Especificamente no caso do parâmetro cor, esta subjetividade obriga muitas indústrias a empregarem valores de controle de cor oriundos de outros estados, ou até mesmo de outros países. No Rio de Janeiro, de acordo com a NT-202-R-10 do INEA, o critério para cor é estar virtualmente ausente no efluente. Neste contexto, este estudo avaliou algumas metodologias empregadas na determinação da cor em um efluente têxtil. Para a medição de cor, foram empregadas três metodologias descritas na literatura. A primeira metodologia desenvolvida para análise de água, também utilizada para efluentes líquidos, se baseia em medições espectrofotométricas em um único comprimento de onda padrão (450nm ou 465nm), tendo como referência soluções de Pt-Co. Essa metodologia não abrange todas as tonalidades do espectro de cores possíveis para os efluentes têxteis. O segundo método se baseia na medição em três comprimentos de onda (436, 525 e 620nm), denominado índice DFZ. O último método investiga os valores máximos de absorbância, na faixa entre 350 e 700nm, na amostra. Os resultados obtidos mostraram que as correções dos valores de medição de cor utilizando os valores máximos de absorbância expressaram melhor a realidade dos dados experimentais, visto que eliminam um possível erro causado pela restrita faixa de detecção do método tradicional, numa região do espectro típica para tonalidades encontradas na água. / The textile finishing processes, mainly the primary ones, like bleaching and cleaning, or secondary finishing, as dyeing and washing, are recognized to have an effect upon the environment because of the water wasting and the amount of wastewater. The textile wastewaters that are coming from those processes presents high concentration of emulsified substances, chlorine particles, solids and organic materials with a lot of toxicity. Theres no doubt the most important problem is the presence of dyes and pigments. Some physical and chemical parameters that are very important on water pollution control are not easy to measure and checking because there are no clear limits for those parameters. This situation may cause wrong evaluation and some contestation on environmental organisms decisions. Mainly on color parameter, that subjectivity almost force companies to search for outside values and methods at other national region or even on another country. At Rio de Janeiro, based on INEAs NT-202-R10, color should be virtually not present on wastewater. So, this research tested three different methods for measure color on textile wastewater described on literature. The first one was developed for analyze color on water, but its also used for wastewater and is based on spectrophotometric measurements at one standard wavelength (450 or 465nm) and Pt-Co standard solution. Unfortunately, this method can not comprise all possible textile effluent hues. The second method for color measurement on wastewater is called DFZ index and uses different measurements on three wavelengths (436, 525 and 620nm) to compare with some values limits. The last one analyzes the maximum absorbance values between 350nm and 700nm. The results pointed that color values corrections using the maximum absorbance values were closest to the real values because eliminates the problem observed with the small wavelength band used for clean water color measurement method.
8

Avaliação de Metodologia para Controle e Medição de Cor em Efluentes Têxteis. / Methodology for Assessment and Control Color Measurement in Waste Textiles.

Gil Leonardo Aliprandi Lucido 01 December 2010 (has links)
Os processos de beneficiamento têxtil, como o alvejamento, a purga, o tingimento e as lavagens são reconhecidamente impactantes ao meio ambiente, tanto do ponto de vista de consumo de água, quanto da geração de efluentes. Os efluentes têxteis oriundos dos processos de beneficiamento se caracterizam por apresentarem elevadas concentrações de substâncias emulsificantes, íons cloreto, sólidos e matéria orgânica, além de alta toxicidade. Mas sem dúvida, o maior problema desses efluentes deve-se a presença de corantes e pigmentos. Alguns parâmetros físico-químicos importantes no controle da poluição hídrica são de difícil medição e consequente monitoramento, principalmente pela ausência de legislação que expresse de maneira clara e objetiva os limites destes parâmetros. Este fato permite avaliações dúbias e contestações aos órgãos ambientais. Especificamente no caso do parâmetro cor, esta subjetividade obriga muitas indústrias a empregarem valores de controle de cor oriundos de outros estados, ou até mesmo de outros países. No Rio de Janeiro, de acordo com a NT-202-R-10 do INEA, o critério para cor é estar virtualmente ausente no efluente. Neste contexto, este estudo avaliou algumas metodologias empregadas na determinação da cor em um efluente têxtil. Para a medição de cor, foram empregadas três metodologias descritas na literatura. A primeira metodologia desenvolvida para análise de água, também utilizada para efluentes líquidos, se baseia em medições espectrofotométricas em um único comprimento de onda padrão (450nm ou 465nm), tendo como referência soluções de Pt-Co. Essa metodologia não abrange todas as tonalidades do espectro de cores possíveis para os efluentes têxteis. O segundo método se baseia na medição em três comprimentos de onda (436, 525 e 620nm), denominado índice DFZ. O último método investiga os valores máximos de absorbância, na faixa entre 350 e 700nm, na amostra. Os resultados obtidos mostraram que as correções dos valores de medição de cor utilizando os valores máximos de absorbância expressaram melhor a realidade dos dados experimentais, visto que eliminam um possível erro causado pela restrita faixa de detecção do método tradicional, numa região do espectro típica para tonalidades encontradas na água. / The textile finishing processes, mainly the primary ones, like bleaching and cleaning, or secondary finishing, as dyeing and washing, are recognized to have an effect upon the environment because of the water wasting and the amount of wastewater. The textile wastewaters that are coming from those processes presents high concentration of emulsified substances, chlorine particles, solids and organic materials with a lot of toxicity. Theres no doubt the most important problem is the presence of dyes and pigments. Some physical and chemical parameters that are very important on water pollution control are not easy to measure and checking because there are no clear limits for those parameters. This situation may cause wrong evaluation and some contestation on environmental organisms decisions. Mainly on color parameter, that subjectivity almost force companies to search for outside values and methods at other national region or even on another country. At Rio de Janeiro, based on INEAs NT-202-R10, color should be virtually not present on wastewater. So, this research tested three different methods for measure color on textile wastewater described on literature. The first one was developed for analyze color on water, but its also used for wastewater and is based on spectrophotometric measurements at one standard wavelength (450 or 465nm) and Pt-Co standard solution. Unfortunately, this method can not comprise all possible textile effluent hues. The second method for color measurement on wastewater is called DFZ index and uses different measurements on three wavelengths (436, 525 and 620nm) to compare with some values limits. The last one analyzes the maximum absorbance values between 350nm and 700nm. The results pointed that color values corrections using the maximum absorbance values were closest to the real values because eliminates the problem observed with the small wavelength band used for clean water color measurement method.

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