Thesis--Basel. / Vita. Includes bibliographical references.

Thesis (MScIng)--University of Stellenbosch, 2007. / Bibliography.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains vii, 92 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 73-74).

Made available in DSpace on 2014-06-11T19:25:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-03-05Bitstream added on 2014-06-13T20:33:15Z : No. of bitstreams: 1 sousa_ecp_me_ilha_prot.pdf: 3838753 bytes, checksum: fb1abbca6e1c68797f42ad16a38d7a47 (MD5) / Vidros preparados a partir de massa fundida podem nuclear ou cristalizar novas fases quando são submetidos a tratamentos térmicos acima da temperatura de transição vítrea. Neste traba- lho foram apresentados estudos sobre a cinética de cristalização de vidros teluritos do sistema 80TeO2 –10WO3 –(10–x)Li2 O–xNa2 O, x = 0, 2, 4, 6 e 10% mol, denominado sistema TLWN. As principais teorias sobre nucleação e cristalização de vidros foram detalhadas, tais como: Teoria Clássica de Nucleação, Teoria Clássica de Nucleação Modificada, Teoria de Nucleação Adiabática e Teoria JMAK. Classicamente, o estudo da cristalização de vidros pode ser realizado através da teoria formulada por Johnson–Mehl–Avrami–Kolmogorov (JMAK), a qual descreve os processos de nucleação e cristalização, por intermédio das curvas de calorimetria exploratória diferencial – DSC. Os vidros foram sintetizados pelo método de resfriamento rápido (melt–quenching ). Medidas de DSC foram realizadas a diferentes taxas de aquecimento e com diferentes tama- nhos de partículas para estudar a cinética de cristalização dos vidros. Foi evidenciado o caráter amorfo de alguns vidros e para o vidro TLWN6 foram encontradas diferentes fases cristalinas, tais como: Na2 (TeW2 O9 ), Li2 Te2 O5 , WO3 , α–TeO2 e γ–TeO2 , dispersas na matriz devido aos di- versos tratamentos térmicos realizados em torno das temperaturas correspondentes aos máximos dos picos de cristalização e evidenciadas por DRX. Deconvoluções foram realizadas utilizando funções gaussianas para separar os picos sobrepostos da amostra TLWN6. Ficou evidente, por intermédio da análise dos termogramas, que o número de picos de cristalização aumenta com o incremento do óxido de sódio e também que os vidros teluritos deste sistema não possuem boa estabilidade térmica, quando... / The glasses prepared from the melt mass may crystallize or nuclear new phases when subjected to heat treatment above the glass transition temperature. In this work were presented studies on the kinetics of nucleation and crystallization of glasses tellurite of the system 80TeO2 –10WO3 – (10–x)Li2 O–xNa2 O, x = 0, 2, 4, 6 e 10% mol called TLWN system. The main theories on nucleation and crystallization of glasses have been detailed, such as: Classical Theory of Nucle- ation, Modified Classical Theory of Nucleation, the Nucleation Adiabatic Theory and Theory JMAK. Classically, the study of crystallization of glasses can be performed by theory formu- lated by Johnson–Mehl–Avrami–Kolmogorov (JMAK) which describes processes of nucleation and crystallization through of differential scanning calorimetry curves – DSC. The glasses were synthesized by the method of melt - quenching. DSC measurements were made at different hea- ting rates and with different particle sizes to study the crystallization kinetics of glass. It became evident amorphous character of some glasses and glass TLWN6 different crystalline phases have been found, such as Na2 (TeW2 O9 ), Li2 Te2 O5 , WO3 , α–TeO2 e γ–TeO2 , dispersed in the matrix due to the different heat treatments performed in around the temperatures corresponding to the peak maximum crystallization and evidenced by XRD. Deconvolutions were performed using gaussian functions to separate overlapping peaks TLWN6 sample. It became evident through the examination of thermographs, that the number of peaks of crystallization increases with the increase of sodium oxide and also that this system tellurite glasses do not have good thermal stability when compared to traditional glasses. The activation energies of the crystalline pha- ses were obtained using the... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:29:10Z (GMT). No. of bitstreams: 0 Previous issue date: 1999Bitstream added on 2014-06-13T18:38:54Z : No. of bitstreams: 1 bueno_la_me_araiq.pdf: 2056886 bytes, checksum: 478aa5eac56dfc7c1ea0cfc99298d6e6 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Este trabalho teve por objetivo principal a preparação de vitrocerâmicas transparentes no sistema PbGeO3-PbF2-CdF2 e a determinação do domínio vítreo no diagrama de composições para este sistema. Observou-se que a introdução dos óxidos de germânio e chumbo na forma de metagermanato de chumbo (PbGeO3) propiciou a diminuição da perda de íons fluoreto durante a síntese das amostras. Foram obtidos vidros bastante estáveis frente a ristalização, com boa qualidade óptica contendo alta concentração de metais pesados. A estrutura local nos vidros foi determinada utilizando-se as técnicas espectroscópicas vibracionais (IV e Raman) e absorção de raios X (EXAFS). Foi possível observar que os vidros possuem unidades estruturais formadas por tetraedros [GeO4] semelhantes àquelas presentes no composto cristalino PbGeO3. Para identificar as fases cristalinas e acompanhar o processo de cristalização em diferentes temperaturas definidas acima da temperatura de transição vítrea, Tg, nas amostras vítreas, foram utilizadas as técnicas de difração raios X, ressonância magnética nuclear de flúor (RMN-19F) e espectroscopia vibracional (IV e Raman). Observou-se que para todas as amostras a primeira fase a cristalizar é o ß-PbF2. Tratamentos térmicos realizados em temperaturas relacionadas ao processo exotérmico denominado pico de ceramização possibilitaram a obtenção de vitrocerâmicas transparentes contendo 0,5% em mol de íons Er3+ ou Eu3+. Através das técnicas de microscopia eletrônica de transmissão (MET), espectroscopia eletrônica de emissão dos íons lantanídios foi possível a identificação de cristais de ß-PbF2:Er3+,Eu3+ da ordem de 6 nm. / In the present study the glass domain in the PbGeO3-PbF2-CdF2 system is reported. Volatile fluoride loss may be diminished by usage of stoichiometric germanate glass, PbGeO3, instead of introducing individual oxides. Homogeneous glasses with good optical quality were obtained. The structural features in these glasses have been determined by vibrational spectroscopy and X-ray absorption spectroscopy (EXAFS). Tetrahedral structural units [GeO4] similar to those found in PbGeO3 crystal were identified. Crystallization process have been studied at differents temperatures above glass transition temperature, Tg, using X ray diffraction, nuclear magnetic resonance (NMR-19F) and vibrational spectroscopy (IR and Raman) techniques to identify the crystalline phases. Crystalline ß-PbF2 phase have been observed in all glass samples. Transparent glass ceramics were obtained by appropriate heat treatments above glass transition temperature (Tg). Glass composition 60PbGeO3-10PbF2-30CdF2 doped with lanthanide ions Er3+ or Eu3+ are suggest as new infrared emitting devices. By using transmission electronic microscopy (TEM) and X-ray diffraction was possible to identified ß-PbF2 crystals size around 6 nm. Spectroscopy measurements suggest that lanthanide ions concentrate in the crystalline domain.

Orientador: Keizo Yukimitu / Banca: João Carlos Silos Moraes / Banca: Walter Maigon Pontuschka / Resumo: Vidros preparados a partir de massa fundida podem nuclear ou cristalizar novas fases quando são submetidos a tratamentos térmicos acima da temperatura de transição vítrea. Neste traba- lho foram apresentados estudos sobre a cinética de cristalização de vidros teluritos do sistema 80TeO2 -10WO3 -(10-x)Li2 O-xNa2 O, x = 0, 2, 4, 6 e 10% mol, denominado sistema TLWN. As principais teorias sobre nucleação e cristalização de vidros foram detalhadas, tais como: Teoria Clássica de Nucleação, Teoria Clássica de Nucleação Modificada, Teoria de Nucleação Adiabática e Teoria JMAK. Classicamente, o estudo da cristalização de vidros pode ser realizado através da teoria formulada por Johnson-Mehl-Avrami-Kolmogorov (JMAK), a qual descreve os processos de nucleação e cristalização, por intermédio das curvas de calorimetria exploratória diferencial - DSC. Os vidros foram sintetizados pelo método de resfriamento rápido (melt-quenching ). Medidas de DSC foram realizadas a diferentes taxas de aquecimento e com diferentes tama- nhos de partículas para estudar a cinética de cristalização dos vidros. Foi evidenciado o caráter amorfo de alguns vidros e para o vidro TLWN6 foram encontradas diferentes fases cristalinas, tais como: Na2 (TeW2 O9 ), Li2 Te2 O5 , WO3 , α-TeO2 e γ-TeO2 , dispersas na matriz devido aos di- versos tratamentos térmicos realizados em torno das temperaturas correspondentes aos máximos dos picos de cristalização e evidenciadas por DRX. Deconvoluções foram realizadas utilizando funções gaussianas para separar os picos sobrepostos da amostra TLWN6. Ficou evidente, por intermédio da análise dos termogramas, que o número de picos de cristalização aumenta com o incremento do óxido de sódio e também que os vidros teluritos deste sistema não possuem boa estabilidade térmica, quando... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The glasses prepared from the melt mass may crystallize or nuclear new phases when subjected to heat treatment above the glass transition temperature. In this work were presented studies on the kinetics of nucleation and crystallization of glasses tellurite of the system 80TeO2 -10WO3 - (10-x)Li2 O-xNa2 O, x = 0, 2, 4, 6 e 10% mol called TLWN system. The main theories on nucleation and crystallization of glasses have been detailed, such as: Classical Theory of Nucle- ation, Modified Classical Theory of Nucleation, the Nucleation Adiabatic Theory and Theory JMAK. Classically, the study of crystallization of glasses can be performed by theory formu- lated by Johnson-Mehl-Avrami-Kolmogorov (JMAK) which describes processes of nucleation and crystallization through of differential scanning calorimetry curves - DSC. The glasses were synthesized by the method of melt - quenching. DSC measurements were made at different hea- ting rates and with different particle sizes to study the crystallization kinetics of glass. It became evident amorphous character of some glasses and glass TLWN6 different crystalline phases have been found, such as Na2 (TeW2 O9 ), Li2 Te2 O5 , WO3 , α-TeO2 e γ-TeO2 , dispersed in the matrix due to the different heat treatments performed in around the temperatures corresponding to the peak maximum crystallization and evidenced by XRD. Deconvolutions were performed using gaussian functions to separate overlapping peaks TLWN6 sample. It became evident through the examination of thermographs, that the number of peaks of crystallization increases with the increase of sodium oxide and also that this system tellurite glasses do not have good thermal stability when compared to traditional glasses. The activation energies of the crystalline pha- ses were obtained using the... (Complete abstract click electronic access below) / Mestre

L’étude présentée ici est consacrée à une approche expérimentale dans les verres silicatés d’alcalins lourds : (SiO2)1-x(Rb2O)x et (SiO2)1-x(Cs2O)x. La polymérisation du réseau est dépendante de la composition du verre, la concentration en cation modificateur ainsi que sa nature vont donc être des facteurs importants influençant la topologie du réseau silicaté. Afin de mieux comprendre les propriétés de ces verres, il est indispensable d'en connaître la structure. Dans ce travail nous nous sommes particulièrement intéressés à l’ordre à moyenne distance qui contrôle les propriétés mécaniques, et à l’ordre à courte distance déterminant pour les propriétés optiques. La spécificité de ce travail réside dans la volonté comprendre le rôle des cations lourds sur la structure et les propriétés du réseau silicaté, dans les binaires alcalins, à l’échelle macroscopique à l’aide de diffusion Brillouin et à l’échelle microscopique en utilisant les spectroscopies Raman et Infrarouge. / The study presented here is devoted to an experimental approach in heavy alkali silicate glasses (SiO2)1-x (Rb2O)x and (SiO2)1-x (Cs2O)x. The polymerization of the network is dependent on glass composition, the modifier cation concentration and its nature will be important factors influencing the topology of the silicate network. To better understand the properties of these glasses, it is essential to know the structure. In this work we are particularly interested in the medium-range order, which controls the mechanical properties, and short-range order for determining the optical properties. The specificity of this work lies in the will understand the role of heavy cations on the structure and properties of silicate network in the binary alkali at the macroscopic scale using Brillouin scattering and microscopic scale using Raman and Infrared spectroscopy.

Annotation I ame discussing a theme of glass jewellery in my Diploma Work. I am concerned with the ar of author jewellery in Czech Republic in specially chosen group of ten artists, which create glass artefacts. I used quantitative method of analysis for evaluation of theri work and combined it with my subjective impression. The results of my work are interesting gor aspect qualities of glass artefacts.

This is a thesis in two parts. Chapters one to four examine the circumstances of the stained glass revival in Scotland while chapters five to eight identify the particular character of nineteenth century Scottish glass painting up to the 1870s. The opening question is whether or not by the early nineteenth century glass painting was truly an art in decline and this discussion leads into the investigation of the significance of progress in the glass industry to the stained glass revival. This line of questioning continues with the identification of the pioneers of the stained glass revival in Scotland, re-assessing the contribution of James Ballantine and introducing William Cooper. The initial demand for stained glass in Scotland is explored through reference to genealogy, antiquarianism and High Church practice. Edinburgh offered unique opportunities for apprentice glass painters to acquire an art education and this thesis moves on to discuss how this influenced their approach to glass painting, focusing upon the career of Francis Wilson Oliphant. It argues that the commissions which shaped the future direction of Scottish glass painting were the rebuilding of the Houses of Parliament and the re-glazing of Glasgow Cathedral where, in both cases, German glass painting was nominated as the approved artistic model. As it was eventually decided that the new windows for Glasgow Cathedral should be designed and executed by the Königliche Glasmalereianstaff of Munich, thesis concludes with a demonstration of the subsequent German influence upon Scottish glass painting.

Vitrification is a well-established waste treatment method that has been used for silicate based wastes to achieve waste volume reduction and improve chemical stability before further use. However, the poor mechanical strength of the vitrified products has led to a low commercial value and thus an unjustifiable use of energy-intensive thermal technology over the cheaper, although environmentally unsatisfactory, land disposal option. To overcome this issue, the emphasis of this work lies in demonstrating the feasibility of fabricating dense glass-ceramics from several types of waste and combination of wastes, which are generally superior to their parent glasses in their mechanical performance, as well as highly porous glassceramics to be used in building industries as an alternative to conventional waste disposal. The first part of the research work demonstrated the ease of production of an array of relatively dense glass-ceramic material from coal ash from thermal power plants using powder sintering technology. These products had robust physical and mechanical properties suitable to compete against commercially available building materials such as granite and marble for the floor and wall covering applications. A fully-dense, fine-grained, high-strength glass-ceramic was also fabricated from Feslag using an economically viable single-stage melt heat-treatment route. The ironslag derived glass-ceramic material had a unique composition, with an associated microstructure containing a high content of titanium-rich compounds, and has the potential for non-critical load-bearing applications. Finally, the thesis provides the results of an experimental study concerning with the production of highly porous glass-ceramic foams from a mixture of coal ash and waste glass with the addition of an inorganic foaming agent. The correlations between physical, thermal, and mechanical properties were carried out based on results from practical experiments, physical model studies and numerical simulations using X-ray microtomography and finite element analysis. It was concluded that, these waste-derived materials have the potential to be used in building applications where there can be a large demand to meet the large volumes of wastes available.