Esta tese de doutoramento é o resultado de duas pesquisas lexicográficas: a primeira, baseada no corpus estudado de oito minidicionários, seis publicados no Brasil e dois em Portugal, através da coleta, tabulação e análise contrastiva do nível de resolução dos itens lexicais da Introdução & apêndices, macro e microestruturas; a Segunda, uma pesquisa de campo, por amostragem, realizada na cidade de São Paulo, envolvendo alunos e professores do ensino fundamental e médio de duas escolas da rede particular e três da rede pública. A análise léxico-estatística do nível de resolução dos minidicionários compreendeu: Introdução & apêndices, em que analisamos Introdução & apêndices, a macroestrutura, em que priorizamos os empréstimos, lacunas, locuções, neologismos, nomes próprios, prefixo contra, prefixos e sufixos, siglas e microestrutura, através de antônimos e sinônimos, artigo definido, aumentativo irregular, campo lexical, contextos, definições, definições circulares, diminutivo irregular, divisão silábica, domínio, gênero feminino, formas sincréticas, homófonos, homógrafos, linguagem de explicação, parônimas, plural das palavras compostas, polissemia, predicação verbal, remissivas, rotulações, superlativos absolutos sintéticos, tautologia, vocabulário de explicação e vogal tônica/átona. A pesquisa de campo por amostragem foi feita por meio de quase 900 questionários, dos quais selecionamos 311 para nossa análise final, representativos do universo de alunos matriculados no ensino médio do Brasil em 1999. Estas análises pretenderam ser representativas do corpus total, tanto de minidicionários atualmente publicados no Brasil, como de alunos matriculados no ensino médio brasileiro. Expomos, ainda, o panorama histórico da produção lexicográfica em minidicionários, os fundamentos teóricos, estabelecimento do corpus e metodologia, uma análise de dois campos lexicais (peixes e frutos) e a tipologia dos dicionários monolíngues e a bibliografia. Das pesquisas acima, apresentamos, como conclusão do trabalho, uma sugestão de modelo de Superminidicionário de língua portuguesa para o ensino médio. / This doctorate thesis contains the results of two lexicographical piece of research. The first is based on the studied corpus of eight minidictionaries, six published in Brazil and two in Portugal, through the collection, tabulation and contrastive analysis of the level of resolution of the lexical items in the introduction and appendixes, in relation to their macro- and microstructures. The second is a piece of sampling field research carried out in the city of São Paulo. It involved students and teachers of fundamental and medium teaching at two schools in the private sector and three in the public sector. A lexical-statistical analysis of the level of resolution of the minidictionaries in the introduction and appendixes was carried out in that the introduction and appendixes were analysed. We looked at the macrostructure, in that we prioritized the loans, gaps, locutions, neologisms, proper names, prefixes against, prefixes and suffixes and acronyms. In addition, we looked at the microstructure, through considering the antonyms and synonyms, defined articles, irregular augmentatives, lexical field, contexts, definitions, circular definitions, irregular diminutives, syllabic divisions, domains, feminine gender, syncretic forms, homophones, homographs, explanatory language, paronyms, plurals of the composed words, instances of polysemy, predicative verbs, cross-references, labelling, synthetic absolute superlatives, tautologies, explanatory vocabulary and open/closed vowels. The sampling field research was conducted through giving out almost 900 questionnaires, out of the which we selected 311 for our final analysis, as these were representative of the enrolled students\' as a whole in the medium teaching in Brazil in 1999. These analyses are intended to be representative of the total corpus. So many of the minidictionaries are now published in Brazil, as of enrolled students in high education in Brazil. We further expose the historical panorama of the lexicographical production in minidictionaries, the theoretical foundation, the establishment of the corpus and methodology, an analysis of two lexical fields (fish and fruits) and the typology of the monolingual dictionaries and the bibliography. From the research above, we present, as a conclusion to the work, a suggestion for a model of a super-minidictionary of the Portuguese language for higher education. My thesis advisor was Professor Maria Vicentina.

by Cheng Kai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references. / by Cheng Kai. / Acknowledgments --- p.i / Abstract --- p.ii / Table of content --- p.iv / Chapter Chapter One --- Introduction / Chapter 1.1 --- Barkhausen emission --- p.1 / Chapter 1.2 --- Methods of measurements --- p.3 / Chapter 1.2.1 --- Magnetization of a sample --- p.4 / Chapter 1.2.2 --- Signal detection --- p.5 / Chapter 1.2.3 --- Signal processing --- p.5 / Chapter 1.3 --- Instrumentation --- p.6 / Chapter 1.3.1 --- Instron loading machine --- p.6 / Chapter 1.3.2 --- Optical microscopy --- p.7 / Chapter 1.3.3 --- Vicker's hardness tester --- p.7 / Chapter 1.3.4 --- Ceramic furnace --- p.8 / References --- p.9 / Chapter Chapter Two --- Domain Theory / Chapter 2.1 --- The postulate of domain --- p.16 / Chapter 2.2 --- Domain energy --- p.18 / Chapter 2.3 --- The magnetization process --- p.20 / Chapter 2.4 --- Effect of applied stress --- p.22 / Chapter 2.5 --- Hindrances to wall motion by inclusions --- p.23 / References --- p.24 / Chapter Chapter Three --- Steels / Chapter 3.1 --- The making of steel --- p.28 / Chapter 3.2 --- The iron-iron carbide phase diagram --- p.29 / Chapter 3.3 --- Heat treatment of plain-carbon steels --- p.29 / Chapter 3.3.1 --- Slow cooling of plain-carbon steels --- p.29 / Chapter 3.3.2 --- Rapid cooling of plain-carbon steels --- p.30 / Chapter 3.3.3 --- Annealing --- p.31 / References --- p.32 / Chapter Chapter Four --- Effects of carbon on Barkhausen emission in plain carbon steel / Chapter 4.1 --- introduction --- p.35 / Chapter 4.2 --- Experiments --- p.36 / Chapter 4.2.1 --- Samples --- p.36 / Chapter 4.3 --- Results and discussions --- p.37 / Chapter 4.4 --- Conclusions --- p.39 / References --- p.40 / Chapter Chapter Five --- Magnetization process in a steel plate/bar subjected to an increasing tensile load / Chapter 5.1 --- Introduction --- p.45 / Chapter 5.2 --- Experiments --- p.47 / Chapter 5.3 --- Results and discussions for the zinc-coated steel plate --- p.47 / Chapter 5.4 --- Results and discussions for mild steel --- p.50 / Chapter 5.5 --- A comparison between steel plate and steel bar --- p.52 / Chapter 5.6 --- Conclusions --- p.53 / References --- p.54 / Chapter Chapter Six --- Evaluation of residual stress in bent steel bars subjected to different heat treatment by Barkhausen emission / Chapter 6.1 --- Introduction --- p.60 / Chapter 6.2 --- Experiments --- p.60 / Chapter 6.3 --- Results and discussions --- p.61 / Chapter 6.4 --- Conclusions --- p.64 / References --- p.65 / Chapter Chapter Seven --- Effects of heat treatment on electrolytic zinc-coated steel plates by Barkhausen emission / Chapter 7.1 --- Introduction --- p.72 / Chapter 7.2 --- Experiments --- p.72 / Chapter 7.3 --- Results and discussions --- p.73 / Chapter 7.4 --- Conclusions --- p.75 / References --- p.76 / Chapter Chapter Eight --- Effects of demagnetizing and stray fields on Barkhausen emission / Chapter 8.1 --- Introduction --- p.80 / Chapter 8.2 --- Experiments --- p.80 / Chapter 8.3 --- Results and discussions --- p.81 / Chapter 8.4 --- Conclusions --- p.85 / References --- p.85 / Chapter Chapter Nine --- Conclusions and suggestions for further studies --- p.90

O benefício do consumo de compostos bioativos, como os carotenóides, tem sido amplamente demonstrado pela literatura científica. No entanto, alguns destes bioativos (como os carotenos), devido à sua hidrofobicidade, apresentam dificuldades para serem incorporados em formulações alimentícias aquosas, além de serem, dependendo da matriz alimentícia na qual estão inseridos, dificilmente absorvidos no tratogastrointestinal - ou seja, possuem limitada biodisponibilidade. Tais problemas podem ser contornados através da micro e da nanoencapsulação. O presente trabalho de Mestrado teve como objetivo utilizar a triestearina e o ácido esteárico para a encapsulação do beta-caroteno em micro e nanopartículas lipídicas sólidas, a caracterização físico-química das estruturas formadas e a avaliação da estabilidade química e microestrutural das mesmas. Nos sistemas microparticulados de ácido esteárico (AE) foi utilizado como tensoativo o polisorbato 80 e foram produzidos com 4 e 6% de lipídio, na ausência e na presença de alfa-tocoferol, e todos se mostram extremamente estáveis em relação à distribuição do tamanho médio das partículas, mas somente as partículas que continham alfa-tocoferol conseguiram preservar o beta-caroteno ao longo do período de 7 meses de armazenagem. No caso das micropartículas de triestearina também foram produzidos sistema com 4 e 6% de lipídio total, e a presença do hidrocolóide goma xantana foi essencial para evitar a floculação e permitir a estabilidade do sistema, e foram testadas formulações contendo misturas de tensoativos fosfatidilcolina de soja e polisorbato 60 e fosfatidilcolina de soja e polisorbato 20. Dentre tais sistemas, somente as micropartículas sólidas estabilizadas com polisorbato 60 se mostraram estáveis em relação ao tamanho médio das partículas, e o sistema com menor quantidade de lipídio manteve-se resistente à floculação até o 4º mês de estocagem. Sistemas nanoparticulados foram produzidos com 6% de lipídio total, testando-se uma e duas passagens no homogeneizador à alta pressão. Os dados obtidos indicaram que as nanopartículas lipídicas de AE não diferiram em relação à distribuição de tamanho, mas apresentaram aumento do diâmetro de partícula ao longo do tempo de estocagem. Por sua vez, para as nanopartículas de triestearina os sistemas (tanto com uma quanto com duas passagens no homogeneizador a alta pressão) se mostraram estáveis até cerca de dois meses de armazenagem, em termos de diâmetro médio de partícula, sendo que a distribuição de tamanho se mostrou mais homogênea para o sistema com duas passagens. A microestrutura de todos os sistemas foi avaliada por difratometria de raio-X (DRX) e calorimetria diferencial de varredura (DSC), e a quantidade de beta-caroteno preservada ao longo do tempo foi monitorada espectofometricamente e por colorimetria instrumental. De maneira geral, os sistemas microparticulados se mostraram melhores do que os nanoparticulados, tanto do ponto de vista de estabilidade da estrutura quanto da preservação do beta-caroteno. / The benefits from the consumption of bioactive compounds, like carotenoids, have been widely demonstrated for scientific literature. However, some of this compounds (like carotenes), due totheir hydrophobicity, are difficult to be incorporated in aqueous food formulations, and, depending on the food matrices where they are introduced, are hardly absorbed in the gastrointestinal tract - in order words, they present limited bioavailability. These problems can be overcome by micro and nanoencapsulation. In this context, the objective of this study was to investigate the temporal stability of beta-carotene encapsulated in solid lipid micro and nano particles produced with a mixture of stearic acid or tristearin and sunflower oil, monitoring the microstructure of the systems by X-ray diffractometry, differential scanning calorimetry, zeta potential and particle size measurements, and try to link the preservation of beta-carotene with microstructural considerations. The surfactant used for the stearic acid microparticulate systems was polysorbate 80 and formulations with 4 and 6% of total lipid were produced, in the absence and presence of alpha-tocopherol, and all systems showed high stability in terms of average particle diameter and size distribution, but only the particles containing alpha-tocopherol preserved the content of beta-carotene during the storage period of 7 months In the case of the tristearin microparticles the presence of a hydrocolloid (xanthan gum) was essential for avoid flocculation and improves the system stability, and formulations containing mixtures of surfactants (soybean phosphatidylcholine and polysorbate 60 and phosphatidylcholine and polysorbate 20) were tested. Among such systems, only the solidmicroparticles stabilized with phosphatidylcholine and polysorbate 60 showed stability in terms of average particle diameter and size distribution, and the system with less concentration of solid lipid did not show significant destabilization until the 4th month of storage. As for the nanoparticulated systems, formulations with 6% of total lipid were produced, testing one and two passages in high pressure homogenizer. Our results indicated the stearic acid solid nanoparticles did not exhibitalterations of size distribution, but average particle diameter increased along the time. On the other hand, the triestearin nanoparticles (both with one and two passage in high pressure homogeneizer) showed stability until two months of storage, in terms of average particle diameter, and the size distribution demonstrated to be more homogeneous for the systems submitted to two passages. As an overall conclusion, the microparticulated systems seemed to be more stable than the nanoparticulated ones, from the point of view of structure stability as well as in terms of beta-carotene preservation of beta-carotene.

Esta tese de doutoramento é o resultado de duas pesquisas lexicográficas: a primeira, baseada no corpus estudado de oito minidicionários, seis publicados no Brasil e dois em Portugal, através da coleta, tabulação e análise contrastiva do nível de resolução dos itens lexicais da Introdução & apêndices, macro e microestruturas; a Segunda, uma pesquisa de campo, por amostragem, realizada na cidade de São Paulo, envolvendo alunos e professores do ensino fundamental e médio de duas escolas da rede particular e três da rede pública. A análise léxico-estatística do nível de resolução dos minidicionários compreendeu: Introdução & apêndices, em que analisamos Introdução & apêndices, a macroestrutura, em que priorizamos os empréstimos, lacunas, locuções, neologismos, nomes próprios, prefixo contra, prefixos e sufixos, siglas e microestrutura, através de antônimos e sinônimos, artigo definido, aumentativo irregular, campo lexical, contextos, definições, definições circulares, diminutivo irregular, divisão silábica, domínio, gênero feminino, formas sincréticas, homófonos, homógrafos, linguagem de explicação, parônimas, plural das palavras compostas, polissemia, predicação verbal, remissivas, rotulações, superlativos absolutos sintéticos, tautologia, vocabulário de explicação e vogal tônica/átona. A pesquisa de campo por amostragem foi feita por meio de quase 900 questionários, dos quais selecionamos 311 para nossa análise final, representativos do universo de alunos matriculados no ensino médio do Brasil em 1999. Estas análises pretenderam ser representativas do corpus total, tanto de minidicionários atualmente publicados no Brasil, como de alunos matriculados no ensino médio brasileiro. Expomos, ainda, o panorama histórico da produção lexicográfica em minidicionários, os fundamentos teóricos, estabelecimento do corpus e metodologia, uma análise de dois campos lexicais (peixes e frutos) e a tipologia dos dicionários monolíngues e a bibliografia. Das pesquisas acima, apresentamos, como conclusão do trabalho, uma sugestão de modelo de Superminidicionário de língua portuguesa para o ensino médio. / This doctorate thesis contains the results of two lexicographical piece of research. The first is based on the studied corpus of eight minidictionaries, six published in Brazil and two in Portugal, through the collection, tabulation and contrastive analysis of the level of resolution of the lexical items in the introduction and appendixes, in relation to their macro- and microstructures. The second is a piece of sampling field research carried out in the city of São Paulo. It involved students and teachers of fundamental and medium teaching at two schools in the private sector and three in the public sector. A lexical-statistical analysis of the level of resolution of the minidictionaries in the introduction and appendixes was carried out in that the introduction and appendixes were analysed. We looked at the macrostructure, in that we prioritized the loans, gaps, locutions, neologisms, proper names, prefixes against, prefixes and suffixes and acronyms. In addition, we looked at the microstructure, through considering the antonyms and synonyms, defined articles, irregular augmentatives, lexical field, contexts, definitions, circular definitions, irregular diminutives, syllabic divisions, domains, feminine gender, syncretic forms, homophones, homographs, explanatory language, paronyms, plurals of the composed words, instances of polysemy, predicative verbs, cross-references, labelling, synthetic absolute superlatives, tautologies, explanatory vocabulary and open/closed vowels. The sampling field research was conducted through giving out almost 900 questionnaires, out of the which we selected 311 for our final analysis, as these were representative of the enrolled students\' as a whole in the medium teaching in Brazil in 1999. These analyses are intended to be representative of the total corpus. So many of the minidictionaries are now published in Brazil, as of enrolled students in high education in Brazil. We further expose the historical panorama of the lexicographical production in minidictionaries, the theoretical foundation, the establishment of the corpus and methodology, an analysis of two lexical fields (fish and fruits) and the typology of the monolingual dictionaries and the bibliography. From the research above, we present, as a conclusion to the work, a suggestion for a model of a super-minidictionary of the Portuguese language for higher education. My thesis advisor was Professor Maria Vicentina.

In this thesis, nanosecond pulsed lasers are used as the tools to generate microstructures on metal and glass. The applications of these structures are described too. The production of micro structures is demonstrated using diode-pumped solid state (DPSS) Nd:YVO4 lasers operating at wavelengths of 532nm or 1064 nm. The laser fluence and scanning speed are important parameters to control the results. The first part of thesis is on the laser generation of microstructures on metal surfaces. Copper (Cu) and titanium (Ti) have been studied. According to the reflectivity of metals, Cu is processed by a 532nm laser and Ti is processed by a 1064nm laser. It is shown that the periods of surface microstructures are highly dependent on the hatch distance (overlapping distance between laser scanning). Only if the laser fluence is greater than a threshold, may the microstructures on metals be induced. The thresholds are measured by the diameters of ablated areas at different fluence. Laser generated surface microstructures have been applied to modify the reflectivity of a Cu sample. It was found that laser induced surface microstructures on Copper can decrease the surface reflectivity by almost 97% between 250 nm and 700 nm. To find the mechanism of how to form microstructure on metal surface with laser, laser ablation and heating models have been studied. The 1D ablated numerical model is calculated in Matlab. The pressure of metal vapour is an important parameter, as it pushes the melted metal out of surface to form microstructures after re-solidification. The second part of thesis is on glass welding with microstructures on glass surfaces. The soda-lime glasses containing silver nanoparticles (from the company Codixx) have been studied and welded with Schott B270 glass. Compared with other techniques for welding glass, lasers offer the advantage of a relatively simple and flexible technique for joining the local area underneath the cover glass. Most of the laser energy is deposited in the Ag nanoparticle layer because of the large absorption coefficient at 532 nm. Expanded microstructures generated by the laser are applied to fill the gap between the glass surfaces. This is attributed to the formation of bubbles in the Ag nanoparticle layer after laser processing. The welded samples have the joint strength of 4.9 MPa and have great potential for industrial applications. A 3D analytical model is used to estimate the temperature of the glass after the laser pulse. The increase in temperature is about 129 °C. To induce the bubble in glass, many laser pulses are necessary. This is very different from the results for the metals.

by Li, Kowk Cheung = 利用木材製作具有生物形態的碳化矽 / 李國彰. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Abstracts in English and Chinese. / by Li, Kwok Cheung = Li yong mu cai zhi zuo ju you sheng wu xing tai de tan hua xi / Li Guozhang. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgements --- p.v / Table of contents --- p.vi / List of figure captions --- p.x / List of table captions --- p.xiv / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Biomorphic products and their potential applications --- p.1 / Chapter 1.2 --- Structures and mechanical behaviors of wood --- p.1 / Chapter 1.3 --- Characteristics and applications of SiC --- p.2 / Chapter 1.4 --- Common methods of producing biomorphic SiC from wood --- p.2 / Chapter 1.4.1 --- Chemical vapor deposition --- p.3 / Chapter 1.4.2 --- Melt infiltration --- p.3 / Chapter 1.4.3 --- Sol-gel process --- p.4 / Chapter 1.5 --- Carbothermal reduction process of silica --- p.5 / Chapter 1.6 --- Objectives of present work --- p.5 / Chapter 1.6.1 --- Comments on the previous works --- p.5 / Chapter 1.6.2 --- Current approaches --- p.6 / References --- p.8 / Chapter Chapter 2 --- Experimental procedures / Chapter 2.1 --- Wood biotemplates --- p.10 / Chapter 2.1.1 --- Balsa --- p.10 / Chapter 2.1.2 --- Flame tree --- p.10 / Chapter 2.2 --- Sol Gel process --- p.11 / Chapter 2.2.1 --- Precursor --- p.11 / Chapter 2.2.2 --- Reaction mechanisms --- p.11 / Chapter 2.2.3 --- "Effects of pH, temperature, and environment" --- p.12 / Chapter 2.3 --- Preparation of biomorphic SiC / Chapter 2.3.1 --- HC1 pretreatment --- p.13 / Chapter 2.3.2 --- Infiltration of silica via sol gel process --- p.13 / Chapter 2.3.2.1 --- Balsa --- p.14 / Chapter 2.3.2.2 --- Flame tree --- p.15 / Chapter 2.3.3 --- Sintering --- p.15 / Chapter 2.3.4 --- Removal of carbon --- p.15 / Chapter 2.4 --- Characterization methods --- p.16 / Chapter 2.4.1 --- Scanning electron microscope and energy dispersive x-ray spectroscopy --- p.16 / Chapter 2.4.2 --- X-ray diffractometry --- p.16 / Chapter 2.4.3 --- Differential thermal analysis --- p.16 / Chapter 2.4.4 --- Compressive strength analysis --- p.17 / Chapter 2.5 --- Summary --- p.17 / References --- p.18 / Figures --- p.19 / Chapter Chapter 3 --- Results and discussions / Chapter 3.1 --- Balsa --- p.21 / Chapter 3.1.1 --- HC1 pretreatment --- p.21 / Chapter 3.1.2 --- Infiltration behaviors --- p.21 / Chapter 3.1.2.1 --- By the standard method --- p.21 / Chapter 3.1.2.2 --- Modified sol-gel process --- p.21 / Chapter 3.1.3 --- SiC products --- p.22 / Chapter 3.1.3.1 --- Volumetric shrinkage and weight loss --- p.22 / Chapter 3.1.3.2 --- Compositions --- p.23 / Chapter 3.1.3.3 --- Morphology and structure --- p.24 / Chapter 3.1.4 --- Optimal infiltration conditions --- p.25 / Chapter 3.2 --- Flame tree --- p.25 / Chapter 3.2.1 --- HC1 pretreatment --- p.26 / Chapter 3.2.2 --- Infiltration behaviors --- p.26 / Chapter 3.2.3 --- SiC products --- p.26 / Chapter 3.2.3.1 --- Volumetric shrinkage and weight loss --- p.26 / Chapter 3.2.3.2 --- Composition --- p.27 / Chapter 3.2.3.3 --- Morphology and structure --- p.27 / Chapter 3.3 --- Mechanisms for the formation of SiC cell walls --- p.30 / Chapter 3.4 --- Compressive strength --- p.31 / Chapter 3.5 --- Summary --- p.34 / References --- p.35 / Tables --- p.36 / Figures --- p.38 / Appendix --- p.65 / Chapter Chapter 4 --- Conclusions and future works / Chapter 4.1 --- Summary --- p.67 / Chapter 4.2 --- Suggestions for future work --- p.68 / References --- p.70

O benefício do consumo de compostos bioativos, como os carotenóides, tem sido amplamente demonstrado pela literatura científica. No entanto, alguns destes bioativos (como os carotenos), devido à sua hidrofobicidade, apresentam dificuldades para serem incorporados em formulações alimentícias aquosas, além de serem, dependendo da matriz alimentícia na qual estão inseridos, dificilmente absorvidos no tratogastrointestinal - ou seja, possuem limitada biodisponibilidade. Tais problemas podem ser contornados através da micro e da nanoencapsulação. O presente trabalho de Mestrado teve como objetivo utilizar a triestearina e o ácido esteárico para a encapsulação do beta-caroteno em micro e nanopartículas lipídicas sólidas, a caracterização físico-química das estruturas formadas e a avaliação da estabilidade química e microestrutural das mesmas. Nos sistemas microparticulados de ácido esteárico (AE) foi utilizado como tensoativo o polisorbato 80 e foram produzidos com 4 e 6% de lipídio, na ausência e na presença de alfa-tocoferol, e todos se mostram extremamente estáveis em relação à distribuição do tamanho médio das partículas, mas somente as partículas que continham alfa-tocoferol conseguiram preservar o beta-caroteno ao longo do período de 7 meses de armazenagem. No caso das micropartículas de triestearina também foram produzidos sistema com 4 e 6% de lipídio total, e a presença do hidrocolóide goma xantana foi essencial para evitar a floculação e permitir a estabilidade do sistema, e foram testadas formulações contendo misturas de tensoativos fosfatidilcolina de soja e polisorbato 60 e fosfatidilcolina de soja e polisorbato 20. Dentre tais sistemas, somente as micropartículas sólidas estabilizadas com polisorbato 60 se mostraram estáveis em relação ao tamanho médio das partículas, e o sistema com menor quantidade de lipídio manteve-se resistente à floculação até o 4º mês de estocagem. Sistemas nanoparticulados foram produzidos com 6% de lipídio total, testando-se uma e duas passagens no homogeneizador à alta pressão. Os dados obtidos indicaram que as nanopartículas lipídicas de AE não diferiram em relação à distribuição de tamanho, mas apresentaram aumento do diâmetro de partícula ao longo do tempo de estocagem. Por sua vez, para as nanopartículas de triestearina os sistemas (tanto com uma quanto com duas passagens no homogeneizador a alta pressão) se mostraram estáveis até cerca de dois meses de armazenagem, em termos de diâmetro médio de partícula, sendo que a distribuição de tamanho se mostrou mais homogênea para o sistema com duas passagens. A microestrutura de todos os sistemas foi avaliada por difratometria de raio-X (DRX) e calorimetria diferencial de varredura (DSC), e a quantidade de beta-caroteno preservada ao longo do tempo foi monitorada espectofometricamente e por colorimetria instrumental. De maneira geral, os sistemas microparticulados se mostraram melhores do que os nanoparticulados, tanto do ponto de vista de estabilidade da estrutura quanto da preservação do beta-caroteno. / The benefits from the consumption of bioactive compounds, like carotenoids, have been widely demonstrated for scientific literature. However, some of this compounds (like carotenes), due totheir hydrophobicity, are difficult to be incorporated in aqueous food formulations, and, depending on the food matrices where they are introduced, are hardly absorbed in the gastrointestinal tract - in order words, they present limited bioavailability. These problems can be overcome by micro and nanoencapsulation. In this context, the objective of this study was to investigate the temporal stability of beta-carotene encapsulated in solid lipid micro and nano particles produced with a mixture of stearic acid or tristearin and sunflower oil, monitoring the microstructure of the systems by X-ray diffractometry, differential scanning calorimetry, zeta potential and particle size measurements, and try to link the preservation of beta-carotene with microstructural considerations. The surfactant used for the stearic acid microparticulate systems was polysorbate 80 and formulations with 4 and 6% of total lipid were produced, in the absence and presence of alpha-tocopherol, and all systems showed high stability in terms of average particle diameter and size distribution, but only the particles containing alpha-tocopherol preserved the content of beta-carotene during the storage period of 7 months In the case of the tristearin microparticles the presence of a hydrocolloid (xanthan gum) was essential for avoid flocculation and improves the system stability, and formulations containing mixtures of surfactants (soybean phosphatidylcholine and polysorbate 60 and phosphatidylcholine and polysorbate 20) were tested. Among such systems, only the solidmicroparticles stabilized with phosphatidylcholine and polysorbate 60 showed stability in terms of average particle diameter and size distribution, and the system with less concentration of solid lipid did not show significant destabilization until the 4th month of storage. As for the nanoparticulated systems, formulations with 6% of total lipid were produced, testing one and two passages in high pressure homogenizer. Our results indicated the stearic acid solid nanoparticles did not exhibitalterations of size distribution, but average particle diameter increased along the time. On the other hand, the triestearin nanoparticles (both with one and two passage in high pressure homogeneizer) showed stability until two months of storage, in terms of average particle diameter, and the size distribution demonstrated to be more homogeneous for the systems submitted to two passages. As an overall conclusion, the microparticulated systems seemed to be more stable than the nanoparticulated ones, from the point of view of structure stability as well as in terms of beta-carotene preservation of beta-carotene.

Four batches of pasteurized process cheese were prepared from the same Cheddar cheese by cooking to 82C in the presence of sodium citrate, disodium phosphate, tetrasodium pyrophosphate or sodium aluminum phosphate. Each batch contained the same moisture (40.6%) and emulsifying salt concentration (2.5%). The process cheese was sampled for microstructural and rheological examination after 0, 5, 10, 20 and 40 min in the cooker at 82C. Even though each emulsifying salt affected the physical properties of the process cheese differently, the cheese generally became firmer, stiffer, more elastic and less meltable as cooking time increased from 0 to 40 min. These changes were accompanied by a decrease in the dimension of fat masses and an increase in the degree of emulsification as evidenced by scanning electron microscopy and transmission electron microscopy. The degree of emulsification (fineness of fat particles) seemed directly related to firmness, poor meltability, toughness, breaking force, apparent stiffness modulus, degree of elasticity , apparent ultimate stress and inversely related to hysteresis and apparent ultimate strain. Tetrasodium pyrophosphate produced the most rapid emulsification of the fat in the cheese and sodium aluminum phosphate the slowest. The effect of the other salts was intermediate. The softest most meltable cheese was poorly emulsified while the firmest most sliceable was well emulsified. Sodium citrate and tetrasodium pyrophosphate crystals remained undissolved in the cheese after 40 min in the cooker while sodium aluminum phosphate crystals were still undissolved after 10 min. There was a close statistical relationship among several of the rheological measurements viz. meltability and firmness, toughness and breaking force, and meltability and breaking force. Future rheological studies on process cheese should not require all of the above measurements. An increase in the fineness of the fat emulsion as determined by scanning electron microscopy was generally accompanied by increased firmness, poorer meltability and increased toughness.

Thesis (M.Ed.) --University of Limpopo, 2009. / Some dictionaries are presented in such a way that their target users could not easily retrieve the required semantic information with special reference to Xitsonga/English Dikixinari/Dictionary (2005). Semantic information in the dictionary is presented unsystematically. In some cases extra-linguistic information in the form of contextual guidance is presented, which is regarded as secondary information in the place of semantic information (which is primary). The study evaluates this dictionary in terms of the primary of semantic comments in Xitsonga/English Dictionary. The study finds that translation equivalents are not arranged systematically in the microstructure. The research concludes that extra-linguistic information in a form of contextual guidance must be systematical used in the microstructure of Xitsonga/English Dikixinary/Dictionary (2005) so that dictionary users could be able to retrieve systematic information that could help them to speak the target language in a communicative functional way. This as a result will lead to communicative success. / Not listed

Reef-building corals (Order: Scleractinia) are undergoing rapid taxonomic revision after molecular systematics disputed the relationships at all taxonomic levels within traditional classification. New morphological characters are being used to produce evolutionary relationships supported by molecular phylogenetics. While these characters are providing more congruent taxonomic relationships, their variation has not been fully explored. Additionally, phenotypic plasticity (changes in morphology resulting from environmental factors influencing the expressed phenotype despite a shared genotype) is prevalent amongst Scleractinia. In order to better understand the nature of these characters and explore their variation, I created a series of aquaria-based experiments designed to test the stability of these new morphological characters in response to differing environmental conditions. Light intensity and temperature were chosen as the environmental factors varied in these experiments on the basis of being a known trigger for environmentally-driven plasticity and their importance in calcification rate. In addition to aquaria-based phenotypic plasticity experiments I also examined a group (Family: Euphylliidae) within Scleractinia that had been divided by molecular phylogeny into two disparate groups. My research focused on morphological features viewed at magnifications observable by scanning electron microscopy (SEM) called micromorphology. Although variation in the skeletal micromorphology is observable, the new morphological characters that are used in taxonomy display only small amounts of variation caused by changing environmental conditions and were found to be stable for use in taxonomic studies. Additionally, I found a few micromorphological features distinguishing the two groups previously assigned to Euphylliidae including the shape of the septal margins and the fine-scale skeletal texture.