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Programa de incentivo à destinação correta do vidro; Program of incentives to assign correct of glass

Salata, Robinson
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/04/2008 PT
Relevância na Pesquisa
36.690083%
Muitas das ações e das preocupações orientadas para a destinação mais correta dos resíduos sólidos urbanos, particularmente do vidro de embalagens, acabam por não se concretizarem pela falta de informações básicas, geralmente muito simples e que podem ser disponibilizadas com facilidade. Neste trabalho propomos o desenvolvimento de um programa que incentive os usuários de embalagens de vidro a não descartarem, de maneira indiscriminada e inconsciente, este material. Trata-se, portanto, de um programa de incentivo que busca apoiar, técnica e informacionamente, todos aqueles que hoje são consumidores de embalagens de vidro, embora não tenham como garantir o retoro deste material às recicladoras ou à indústria vidreira. Este trabalho pretende se constituir em um instrumento de apoio a uma atuação mais correta das municipalidades e/ou instituições, na busca de uma destinação mais eficiente das embalagens de vidro consumidas em sua área de atuação. Apesar da indústria vidreira afirmar que tem capacidade instalada para reciclar todo o vidro produzido no Brasil, é sabido que mais da metade da produção anual de embalagens de vidro não retorna às fábricas de vidro. A razão principal é que não há comprador de caco de vidro para as cidades localizadas a mais de 500 km dos centros de produção. A proposta desenvolvida neste trabalho...

Análise da diferenciação osteoblástica in vitro sobre superfícies de materiais vítreos e vitrocerâmicos bioativos; In vitro osteoblastic differentiation on bioactive glass and glassceramic surfaces

Alves, Olivia Cherubin
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/08/2012 PT
Relevância na Pesquisa
36.67104%
Materiais vítreos e vitrocerâmicos bioativos podem ser usados particulados ou como scaffolds em diferentes tratamentos de defeitos ósseos. Tratamentos térmicos que possibilitam o desenvolvimento de scaffolds a partir de composições de vidros bioativos introduzem fases cristalinas em sua estrutura amorfa com potencial impacto na bioatividade e biocompatibilidade do material. O objetivo do presente estudo foi avaliar, qualitativa e quantitativamente, o desenvolvimento do fenótipo osteogênico de culturas de células osteoblásticas sobre substratos vítreos e vitrocerâmicos bioativos. Células MC3T3-E1 foram cultivadas em condições osteogênicas por períodos de até 21 dias sobre superfícies de Bioglass® 45S5, de duas preparações de vitrocerâmica bioativa e altamente cristalina, Biosilicato® e Biosilicato® para scaffold, e de borosilicato (vidro bioinerte). Foram avaliados, nos períodos de 7, 12 e 21 dias, morfologia celular, formação de matriz mineralizada e expressão de genes relacionados à osteogênese. Os resultados mostraram confluência das culturas sobre as superfícies de vidros e vitrocerâmicas, com progressiva formação de multicamadas celulares. A quantificação de vermelho de Alizarina revelou aumento de mineralização para culturas sobre materiais bioativos...

Recycling of glass cullet as aggregate for clays used to produce roof tiles

Costa, F.B.; Teixeira, S.R.; Souza, A.E.; Santos, G.T.A.
Fonte: Rede Latino-Americana de Materiais Publicador: Rede Latino-Americana de Materiais
Tipo: Artigo de Revista Científica Formato: 1146-1153
ENG
Relevância na Pesquisa
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 04/15421-2; Numerous silicates based wastes have been produced and considered for recycling and reuse. Among them, glass cullet is one of the most common silicate wastes and has considerable volume in the cities wastes. A big amount of this waste is recycled by the glass industry but another part is dumped in the cities garbage deposits. In the last few decades there has been considerable research on the reuse of glass waste as aggregate to produce glass-ceramic, for mortars, ceramics and for cement and concrete. This work is concerned to study the reuse of one way glass bottles as aggregate to produce roof tiles (red ceramic). Two kinds of glass powder were prepared by sieving: alpha (0.088 to 0.125 mm) and beta (0.037 to 0.088 mm). Prismatic ceramic bodies (CB) were pressed (60 x 20 x ~5 mm) using a ceramic mass with 0, 5, 8 and 10 % of glass cullet powder added and fired at five different temperatures (800 to 1200 ºC). The results of the technological tests (flexural strength, water absorption, dimensional changes, density and porosity apparent) show that shrinkage increases with the glass content and all other properties above are improved. These changes are more exhibited at temperatures higher than 900°C and in the higher powder glass concentrations (8 e 10%).

Effect of temperature on glass-ceramic films prepared by impregnation of commercial float glass surfaces with oxide powders under pressure

Cava, S.; Sequinel, T.; Tebcherani, S. M.; Lazaro, S. R.; Pianaro, S. A.; Varela, José Arana
Fonte: Elsevier B.V. Sa Publicador: Elsevier B.V. Sa
Tipo: Artigo de Revista Científica Formato: 5889-5891
ENG
Relevância na Pesquisa
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); SnO(2) samples were prepared as ultrafine powder by a chemical synthesis method and deposited on the surface of commercial float glass substrates The glass surface was impregnated with these powders under high gas pressure (1.6-1.8 MPa) and heating to below the glass transition temperature in a designed pressurized chamber, forming SnO(2) films on glass surface Phases were analyzed by X-ray diffraction and the results confirmed the SnO(2) powders as a single-phase tetragonal structure. Analysis of the chemical composition of glass substrates before and after powder impregnation revealed an ion exchange process caused by the substitution of sodium ions by tin ions on the glass surface. Differences in the surface morphology of SnO(2) films on glass surface were related to the morphology of synthesized powders for deposition and impregnation. The mechanism of SnO(2) films on glass surface was based on mass transfer between the glass substrates and SnO(2) powders as a function of the treatment temperature. (C) 2010 Elsevier B.V. All rights reserved.

Osteoconductivity of modified fluorcanasite glass-ceramics for bone tissue augmentation and repair

Bandyopadhyay-Ghosh, S.; Faria, P. E. P.; Johnson, A.; Felipucci, D. N. B.; Reaney, I. M.; Salata, L. A.; Brook, I. M.; Hatton, P. V.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 760-768
ENG
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Modified fluorcanasite glasses were fabricated by either altering the molar ratios of Na 2O and CaO or by adding P 2O 5 to the parent stoichiometric glass compositions. Glasses were converted to glass-ceramics by a controlled two-stage heat treatment process. Rods (2 mm x 4 mm) were produced using the conventional lost-wax casting technique. Osteoconductive 45S5 bioglass was used as a reference material. Biocompatibility and osteoconductivity were investigated by implantation into healing defects (2 mm) in the midshaft of rabbit femora. Tissue response was investigated using conventional histology and scanning electron microscopy. Histological and histomorphometric evaluation of specimens after 12 weeks implantation showed significantly more bone contact with the surface of 45S5 bioglass implants when compared with other test materials. When the bone contact for each material was compared between experimental time points, the Glass-Ceramic 2 (CaO rich) group showed significant difference (p = 0.027) at 4 weeks, but no direct contact at 12 weeks. Histology and backscattered electron photomicrographs showed that modified fluorcanasite glass-ceramic implants had greater osteoconductivity than the parent stoichiometric composition. Of the new materials...

Glass foam of macroporosity using glass waste and sodium hydroxide as the foaming agent

Bento, André C.; Kubaski, Evaldo T.; Sequinel, Thiago; Pianaro, Sidnei A.; Varela, José Arana; Tebcherani, Sergio M.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 2423-2430
ENG
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Glass foams using float glass waste and sodium hydroxide were produced. The influence of the sodium hydroxide amount in the foam formulation was studied. Titanium dioxide was used as a strengthening agent. The variations of temperature, heating rate and sintering time were investigated during the synthesis process. Open porosity was estimated using mercury porosimetry. The morphology of the glass foams was evaluated using scanning electron microscopy, phase formation was studied using X-ray diffraction, and chemical composition was estimated using X-ray fluorescence. As a result, glass foams with macroporosity were obtained. Since the glass foams used glass waste as reactant, the results suggest the development of an alternative route for glass recycling. © 2012 Elsevier Ltd and Techna Group S.r.l.

Experimental analysis on steel reinforced glass beams at different temperatures

Cruz, Paulo J. S.; Valente, Isabel; Carvalho, Paulo L. L.; Marinho, B.; Ribeiro, Samuel
Fonte: COST Action TU0905 Publicador: COST Action TU0905
Tipo: Conferência ou Objeto de Conferência
Publicado em 18/04/2013 ENG
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This work is funded by FEDER Funds, through the Operational Programme Competitiveness Factors – COMPETE, and Portuguese Funds, through FCT - Foundation for Science and Technology, under the project PTDC/ECM/116609/2010, “S-GLASS: Structural Performance and Design Rules of Glass Beams Externally Reinforced”. In addition, The COST Action TU0905 ‘‘Structural Glass – Novel Design Methods and Next Generation Products’’ is also acknowledged.; Whereas glass components were used as infill elements in the past, contemporary architectural concepts include glass components as load-bearing elements. Recent architectural trends and technological developments have brought about unprecedented opportunities in the use of glass in buildings. The increasingly daring structural applications of glass will continue to drive the development of structural glass elements with high post-failure resistances. The present work aims to explore the concepts of structural performance of glass beams and the effectiveness of an embedded steel reinforcement system. The reinforcement system consists in embedding perforated stainless steel plates in the lamination process. The experimental study focuses on the effect of thermal actions and compares the use of soft foils and stiff foils (temperature ranging from approximately 16 ºC to 85 ºC).; Fundação para a Ciência e a Tecnologia (FCT)

Vidro estrutural em condições extremas: aplicações em ambiente submerso; Structural glass in extreme conditions: underwater applications

Sousa, João Tiago Maia
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Trabalho de Conclusão de Curso
Publicado em //2014 POR
Relevância na Pesquisa
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Dissertação de mestrado integrado em Engenharia Civil; O vidro é um material milenar. No entanto, a sua utilização na construção tem apenas alguns séculos. Depois de uma constante evolução no processo de fabrico de vidro, nos dias de hoje é possível criar painéis de vidro liso com elevadas resistências, que além de serem usados como elementos decorativos, cada vez mais são utilizados como elementos estruturais. Nesta dissertação foi feito um estudo da aplicação do vidro como elemento estrutural num caso muito específico, a sua utilização em ambiente submerso, nomeadamente a sua utilização em piscinas e aquários. Este tipo de estruturas, devido aos seus requisitos funcionais, requer elevados cuidados no processo de estudo e dimensionamento. Ao longo deste trabalho foram estudadas soluções estruturais de vidro laminado tendo em consideração os fatores que influenciam a aplicação deste tipo de material em ambiente submerso. Neste contexto, o estudo compreendeu uma componente de trabalho experimental e posteriormente uma avaliação com recurso a modelos numéricos do comportamento estrutural dos elementos de vidro estudados. Numa primeira fase procedeu-se ao ensaio experimental do vidro em flexão simples tendo por base a norma EN 1288-3...

On the evaluation of the mechanical behaviour of structural glass elements

Costa, S.; Miranda, M.; Varum, H.; Teixeira-Dias, F.
Fonte: Trans Tech Publications Publicador: Trans Tech Publications
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Glass can be considered to be a high-technology engineering material with a multifunctional potential for structural applications. However, the conventional approach to the use of glass is often based only on its proper-ties of transparency and isolation. It is thus highly appropriate and necessary to study the mechanical behaviour of this material and to develop adequate methods and models leading to its characterisation. It is evident that the great potential of growth for structural glass applications is an important opportunity of development for the glass industry and the building/construction sectors. The work presented in this paper is a reflection of this conclusion. The authors shortly present the state-of-the-art on the application of glass as a structural element in building and construction, and refer to other potential fields of application and available glass materials. The experimental procedures and methods adopted in three-point bending tests performed on 500 x 100 [mm(2)] float, laminated and tempered glass specimens with thicknesses between 4 and 19 mm are thoroughly described. The authors evaluated the mechanical strength and stiffness of glass for structural applications. This work contributes to a deeper knowledge of the properties of this material.

On the Evaluation of the Mechanical Behaviour of Structural Glass Elements

Costa, S.; Miranda, M.; Varum, H.; Teixeira-Dias, F.
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
36.659355%
Glass can be considered to be a high-technology engineering material with a multifunctional potential for structural applications. However, the conventional approach to the use of glass is often based only on its properties of transparency and isolation. It is thus highly appropriate and necessary to study the mechanical behaviour of this material and to develop adequate methods and models leading to its characterisation. It is evident that the great potential of growth for structural glass applications is an important opportunity of development for the glass industry and the building/construction sectors. The work presented in this paper is a reflection of this conclusion. The authors shortly present the state-of-the-art on the application of glass as a structural element in building and construction, and refer to other potential fields of application and available glass materials. The experimental procedures and methods adopted in three-point bending tests performed on 500 × 100 [mm2] float, laminated and tempered glass specimens with thicknesses between 4 and 19 mm are thoroughly described. The authors evaluated the mechanical strength and stiffness of glass for structural applications. This work contributes to a deeper knowledge of the properties of this material.

Surface reactivity enhancement of silica-based glass-ceramic scaffolds; Aumento da reactividade superficial de suportes porosos vitroceramicos à base de sílica

Davim, Erika Judith Cardoso Rodrigues
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
36.721973%
A paradigm shift is taking place from using transplanting tissue and synthetic implants to a tissue engineering approach that aims to regenerate damaged tissues by combining cells from the body with highly porous scaffold biomaterials, which act as templates, guiding the growth of new tissue. The central focus of this thesis was to produce porous glass and glass-ceramic scaffolds that exhibits a bioactive and biocompatible behaviour with specific surface reactivity in synthetic physiological fluids and cell-scaffold interactions, enhanced by composition and thermal treatments applied. Understanding the sintering behaviour and the interaction between the densification and crystallization processes of glass powders was essential for assessing the ideal sintering conditions for obtaining a glass scaffolds for tissue engineering applications. Our main goal was to carry out a comprehensive study of the bioactive glass sintering, identifying the powder size and sintering variables effect, for future design of sintered glass scaffolds with competent microstructures. The developed scaffolds prepared by the salt sintering method using a 3CaO.P2O5 - SiO2 - MgO glass system, with additions of Na2O with a salt, NaCl, exhibit high porosity, interconnectivity...

Recycling of glass cullet as aggregate for clays used to produce roof tiles

Costa,F.B.; Teixeira,S.R.; Souza,A.E.; Santos,G.T.A.
Fonte: Rede Latino-Americana de Materiais Publicador: Rede Latino-Americana de Materiais
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 PT
Relevância na Pesquisa
36.645754%
Numerous silicates based wastes have been produced and considered for recycling and reuse. Among them, glass cullet is one of the most common silicate wastes and has considerable volume in the cities wastes. A big amount of this waste is recycled by the glass industry but another part is dumped in the cities garbage deposits. In the last few decades there has been considerable research on the reuse of glass waste as aggregate to produce glass-ceramic, for mortars, ceramics and for cement and concrete. This work is concerned to study the reuse of one way glass bottles as aggregate to produce roof tiles (red ceramic). Two kinds of glass powder were prepared by sieving: alpha (0.088 to 0.125 mm) and beta (0.037 to 0.088 mm). Prismatic ceramic bodies (CB) were pressed (60 x 20 x ~5 mm) using a ceramic mass with 0, 5, 8 and 10 % of glass cullet powder added and fired at five different temperatures (800 to 1200 ºC). The results of the technological tests (flexural strength, water absorption, dimensional changes, density and porosity apparent) show that shrinkage increases with the glass content and all other properties above are improved. These changes are more exhibited at temperatures higher than 900°C and in the higher powder glass concentrations (8 e 10%).

Low frequency Raman scattering in amorphous materials: fused quartz, "pyrex" boro-silicate glass and soda-lime silicate glass

Elozi, Khaled.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
ENG
Relevância na Pesquisa
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Raman scattering in the region 20 to 100 cm -1 for fused quartz, "pyrex" boro-silicate glass, and soft soda-lime silicate glass was investigated. The Raman spectra for the fused quartz and the pyrex glass were obtained at room temperature using the 488 nm exciting line of a Coherent Radiation argon-ion laser at powers up to 550 mW. For the soft soda-lime glass the 514.5 nm exciting line at powers up to 660 mW was used because of a weak fluorescence which masked the Stokes Raman spectrum. In addition it is demonstrated that the low-frequency Raman coupling constant can be described by a model proposed by Martin and Brenig (MB). By fitting the predicted spectra based on the model with a Gaussian, Poisson, and Lorentzian forms of the correlation function, the structural correlation radius (SCR) was determined for each glass. It was found that to achieve the best possible fit· from each of the three correlation functions a value of the SCR between 0.80 and 0.90 nm was required for both quartz and pyrex glass but for the soft soda-lime silicate glass the required value of the SCR. was between 0.50 and 0.60 nm .. Our results support the claim of Malinovsky and Sokolov (1986) that the MB model based on a Poisson correlation function provides a universal fit to the experimental VH (vertical and horizontal polarizations) spectrum for any glass regardless of its chemical composition. The only deficiency of the MB model is its failure to fit the experimental depolarization spectra.

Microstructured tellurite glass fibre laser development.

Oermann, Michael Raymond
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011
Relevância na Pesquisa
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This thesis contains a study of the suitability of tellurite glass for use in microstructured fibre lasers. This thesis looks into the possibility for lasing at around 3μm, where tellurite glass is transparent. To test the lasing potential of fabricated tellurite glass microstructured fibres, lasing at 1.5μm was demonstrated. The research contained within this thesis includes: The development and characterisation of the tellurite glass composition; including modifications made to this composition to match the refractive indices of the doped and undoped glasses, reducing the glass material loss, finding the glass crystallisation stability and density as well as measuring the temperature dependence of the glass melt viscosity, of which an understanding is required for its extrusion (Chapter 2). The fabrication of microstructured tellurite fibres which included large mode area fibres, motivated by the desire to fabricate a double clad fibre and the development of small core fibres which were used in the fibre laser experiments (Chapter 3). A spectroscopic study of the erbium III doped glass including lifetimes, absorption and emission measurements (Chapter 4) and a description of the laser modelling, experiments and results (Chapter 5).; Thesis (Ph.D.) -- University of Adelaide...

Soft-glass microstructured optical fibres for nonlinear applications.

Zhang, Wen Qi
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2012
Relevância na Pesquisa
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The objective of this thesis is to explore the potentials of using soft-glass (non-silica) based microstructured optical fibres (MOFs) for nonlinear optical applications. The high linear and nonlinear refractive indices of soft glasses and the ability to tailor the dispersion properties of MOFs have made them an ideal platform for developing nonlinear optical applications. Soft glasses also provide the possibilities of developing waveguides with mid-infrared transmission capability. In addition, the advances in fabricating MOFs with sub-wavelength structures and high refractive index contrast mean that nonlinear processes in these fibres can no longer accurately explored using conventional theories (namely scalar theories). A full vectorial theory is thus required, and this thesis drives forward some applications of recently developed generalised nonlinear theory. In this work, the author studies soft-glass MOFs from two aspects. The first aspect is to develop soft-glass MOFs for new frequency light generation using the scalar theories. The second aspect is to explore new nonlinear phenomena in sub-wavelength scale high-index-contrast waveguides, which includes soft-glass MOFs, using a full vectorial theory. The goal of studying these two aspects is develop a general theory that can explain and accurately predict all nonlinear effects in all types of waveguides. Progress towards two novel nonlinear light sources is described...

Chinese Glass before the Han Dynasty; Die chinesische Gläser vor der Han Dynastie

Li, Hui
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
Relevância na Pesquisa
36.750278%
According to archaeological evidence, the earliest glass eye beads were discovered in Egypt, which date back to early third millennium B.C. The eye beads occurred as the earliest glass products in China after ninth century B.C. It soon became clear that these beads not only resembled Western specimens were decorative motifs where concerned, but also paralleled their chemical composition. Other kinds of glass artifacts emerged after the first occurrences of glass eye beads. In this context, unmistakable similarities in shape and decorative motifs leave no doubt that glass bi discs and glass furniture for swords are imitations of traditional Chinese jade or bronze artifacts. The visible analogies also allow for the conclusion that such forged glass products were manufactured in China. The glass eye beads with composition of lead and barium and Chinese typical characteristic glass products, such as glass bi discs and glass furniture for swords suggest that at least in middle Warring States Chinese could produce glass on their own. On the other hand, the fact that Chinese began to manufacture true glass shortly after eye beads were first imported into Hunan province, indicates that the technique necessary for glass-making was introduced simultaneously with glass eye bead and allowed for Changsha to become a new center of glass production other than other states in north China. As the distribution of glass artifacts shows...

Hohlglas aus Westfalen-Lippe. Vergleichende Untersuchungen zu archäologischen Funden des Mittelalters und der Neuzeit; Hollow glass from Westfalia-Lippe. A comparative investigation into medieval and modern archaeological finds

Tausendfreund, Heike
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE
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36.757268%
HOHLGLAS AUS WESTFALEN-LIPPE. VERGLEICHENDE UNTERSUCHUNGEN ZU ARCHÄOLOGISCHEN FUNDEN DES MITTELALTERS UND DER NEUZEIT. In dieser Arbeit werden Hohlgläser aus verschiedenen archäologischen Ausgrabungen in Westfalen-Lippe vom 12. bis zum 20. Jahrhundert untersucht. Der Auswertungsteil beinhaltet eine Analyse von Fundstücken aus Fundorten der Kategorien „Burg/Herrensitz“, „Kloster/sakrale Einrichtung“ und „Stadt“ und einen Vergleich der westfälisch-lippischen Hohlgläser mit den Funden aus überregionalen Gebieten. Bei der Analyse von drei exemplarisch für die Fundorttypen untersuchten Ausgrabungsstätten wird deutlich, dass dort das Auftreten von Hohlglas generell in seiner zeitlichen Entwicklung dem der Gesamtfundmenge aus Westfalen-Lippe entspricht. Weiterhin zeigt sich, dass die Analyse von ausgesuchten Fundorten stellvertretend für die Gesamtanzahl schwierig ist, weil die zutage getretenen Funde sehr unterschiedlich sind. Bei dieser Analyse kann es sich nur um eine vorsichtige Annäherung an die früheren Lebensbedingungen der Menschen handeln. Der zweite Punkt der Auswertung ist ein überregionaler Vergleich, in dem das Fundgut aus Westfalen-Lippe mit Hohlgläsern aus Nord- und Süddeutschland, den Niederlanden und England verglichen wird. Diese Gegenüberstellung war nur durch eine Auswahl an Glas- und Ausgrabungsliteratur der entsprechenden Gebiete möglich und hat keinerlei Anspruch auf Vollständigkeit. In den ersten Jahrhunderten des Vergleichszeitraumes ließen sich große Abweichungen der Glasformen erkennen. Diese verschwanden erst im 16. Jahrhundert mit der Glasproduktion à la Façon de Venise. Dieser Trend breitete sich bis ins 17. Jahrhundert über ganz Europa aus und hatte eine Vereinheitlichung der Glastypen und einen Anstieg der Glasherstellung zur Folge. Dies bewirkte niedrigere Preise für Gläser...

Properties of glass-ceramics obtained from crystallization of the SiO2-Al2O3-MgO-Li2O system with addition of ZrO2

Souza Filho, Manoel Pereira de; Campos, Elson de; Moreira, Janaina Pardi; Lopes, Cristina Moniz Araujo; Melo, Francisco Cristóvão Lourenço de
Fonte: Trans Tech Publications Ltd Publicador: Trans Tech Publications Ltd
Tipo: Conferência ou Objeto de Conferência Formato: 369-374
ENG
Relevância na Pesquisa
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This paper presents the study results with glass-ceramics obtained from base glass (MgO-Al2O3- SiO2-Li2O system) with addition of ZrO2 as nucleating agent. The glass was melted at 1650 degrees C for 3 h and at a heating rate of 10 degrees C/min. The molten glass was poured into a graphite mold to obtain monolithic samples and also in water in order to obtain particulate material. Such material was grinded and then pressed by both uniaxial and isostatic pressing methods before being sintered. Both the monolithic and pressed samples were performed under two different conditions of heat treatment so that their nucleation and crystallization occurred. In the first one, the samples were heated to 1100 degrees C with a heating rate of 10 degrees C/min. In the second one, there was an initial heating rate of 10 degrees C/min up to 780 degrees C, which was kept for 5 minutes. After that, the samples were heated to 1100 degrees C at a heating rate of 1 degrees C/min. Microhardness analyses showed that base glass presented values around 7.0 GPa. The glass-ceramics obtained from the powder sintering showed microhardness values lower than those obtained from monolithic samples. The highest hardness values were observed in the samples which were treated with two heating rates...

The Application of Post Consumer Glass as a Cementing Agent in Mine Backfill

Sargeant, Aubrey Lancelot
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 2229822 bytes; application/pdf
EN; EN
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ABSTRACT This research evaluated the application of post consumer glass as a cementing agent in underground mine backfills. The underlying theory indicates that glass is pozzolanic and, when used in finely divided form, reacts as an activator to generate binding products, thus contributing to the development of backfill strength. The objective of the research was to evaluate the strength performance of backfills when Normal Portland Cement (NPC) is replaced with various percentages of post consumer glass. The research evaluated the performance of backfills prepared using tailings from three candidate mines, namely Stobie, David Bell and Kidd Creek. Each backfill was prepared using unique recipes, and the strength and other properties were evaluated at cure times of 7, 14, 28, 56, 112 and 224 days. Laboratory work involved visual, physical and chemical material characterization followed by strength evaluations. Results of strength assessment reveal that glass, when incorporated as part of the binder in backfill development is reactive, and can contribute to the strength of backfill. Further analysis of the results also indicated that the reactivity of glass may be affected by the incorporation of slag within the recipe, the availability of lime and the level of hydration of the binders. The research concluded that...

El vidrio en la civilización egipcia. Descripción de piezas de vidrio del tipo incrustaciones de una colección de la Universidad de Sevilla; The glass in the Egyptian civilization. Description of glass elements considered as glass inlays of an Egyptian Collection of the University of Sevilla

Ruíz-Conde, Antonio; Sánchez-Soto, Pedro José; Villegas Broncano, María Ángeles; Seco Álvarez, M.
Fonte: Sociedad Española de Cerámica y Vidrio Publicador: Sociedad Española de Cerámica y Vidrio
Tipo: Artículo Formato: 204626 bytes; application/pdf
SPA
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[ES] En el presente trabajo, se destaca la importancia que la manufactura y el arte del vidrio tuvo para la civilización egipcia. Se describe a grandes rasgos su evolución histórica y los principales métodos de fabricación. A continuación, se resalta la existencia de una serie de materiales vítreos, denominados genéricamente incrustaciones, que en la época egipcia tuvieron diversos fines, todos ellos de elevado nivel artístico, como son pequeños amuletos, piezas de joyería y otras aplicaciones, entre ellos las máscaras y los cartonajes. Dichos materiales podrían ser precedentes del mosaico vidriado. Como ejemplo de interés de este tipo de manufactura, se han seleccionado una serie de incrustaciones en vidrio procedentes de una colección de Arte Egipcio de la Universidad de Sevilla con el objetivo de darla a conocer. Se describen dichas piezas y se lleva a cabo una discusión crítica sobre las características de las mismas. Los resultados obtenidos en la descripción de estas piezas se relacionan con información disponible en una serie de fuentes bibliográficas sobre incrustaciones, por ejemplo las de vidrio monocromático del Museo Grecorromano de Alejandría, Museo Británico y Museo Egipcio de El Cairo.; [EN] In this work...