11 resultados para Tableware


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The micro-chemical/mineralogical composition of samples of grey-paste imitations of Italic Late Republican black gloss tableware displaying a particular kind of lozenge-shaped decoration (“Losanga pottery”) from Portuguese and Spanish archaeological sites in SW Iberia has been analysed by BSEM + EDS, μXRD, Powder XRD, Portable XRF and μRaman spectroscopy. “Losanga” decorated ceramics have been found throughout the Western Mediterranean. Most of the sherds display a green-brown to greyish-black engobe at the surface resembling the gloss found in Attic pottery from Classical Greece. The overall chemical, mineralogical and fossiliferous homogeneities of the ceramic paste show common features (low K-feldspar/plagioclase ratio, high Ca content, abundance of well-preserved fragments of foraminifera microfossils) that indicate low firing conditions in the kiln ranging from 650 to 900 °C. With respect to the ceramic body, analytical results confirm an enrichment in the surface gloss layer of iron, potassium and aluminium and a depletion in silicon and calcium; the very fine grain size of the surface coating suggests elutriation of iron oxide-rich clays as confirmed by the presence of magnetite, maghemite and goethite in μ-XRD scan. Chemical and mineralogical data also suggest that the firing process was performed in a 600–850 °C temperature range, adopting the well-known technique of alternating oxidizing and reducing firing conditions largely employed at the time. The analytical results, while compatible with the archaeological hypothesis of a common provenance of the raw materials for pottery production from the Guadalquivir valley workshops cannot be considered conclusive due to the similarity in the geological substrate in the two SW Iberian regions under study.

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Os objectivos do presente trabalho foram a investigação dos principais defeitos que ocorrem nos produtos de vidro de mesa produzidos por processos automáticos e o desenvolvimento de novos vidros e tecnologias que permitam aumentar os rendimentos de produção, ou a flexibilidade da operação de conformação. A viscosidade influencia a facilidade de conformação dos produtos. Temperaturas de gota mais baixas, espessuras de parede de produtos mais elevadas e baixas áreas de transferência térmica facilitam a ocorrência de defeitos, sobretudo mecânicos e de superfície. Foram identificados os produtos de vidro de mesa que apresentam maiores dificuldades na conformação, designados por produtos de forma complexa. Por ser um factor relevante na prática, discutiu-se o efeito da quantidade de casco usado na elaboração dos vidros sobre a conformação de produtos de forma complexa. A quantidade de casco influencia a volatilização de fundentes que por sua vez tem efeito sobre as propriedades de trabalhabilidade do vidro. Desenvolveram-se novos vidros compatíveis com a utilização de queimos enriquecidos em oxigénio que são utilizados para reduzirem os defeitos mecânicos e de superfície nos produtos de vidros de mesa prensados. A compatibilidade vidro/tecnologia fez-se com uma modificação do sistema de afinação do vidro. Os vidros modificados apresentam propriedades físicoquímicas semelhantes à do vidro inicial e por isso indicam viabilidade comercial. A tecnologia dos canais corantes foi utilizada para modificar a trabalhabilidade de um vidro base a partir da introdução até 5 % de fritas incolores ricas em Li2O. Os valores de RMS (velocidade relativa de máquina) desceram de 106,8 % para 95,7 % enquanto os valores de Pt (patamar de trabalho) subiram de 100,6 s para 111,3 s com o aumento de frita. As propriedades físico-químicas dos vidros aditivados com frita indicam viabilidade comercial. Esta inovação tecnológica introduz flexibilidade nos processos industriais vidreiros. A composição química do vidro e por isso as propriedades relacionadas com a trabalhabilidade podem ser entendidas como mais uma variável dos processos de conformação e usadas em função das técnicas de conformação disponíveis, da forma dos objectos a conformar e da engenharia da ferramenta moldante utilizada. Foi observada convergência entre os resultados experimentais e os valores calculados a partir dos modelos de Huff e Fluegel nos principais parâmetros da tecnologia vidreira (RMS e Pt) e nas propriedades dos vidros nomeadamente densidade e coeficiente de dilatação térmico. Uma parte importante deste trabalho decorreu em ambiente industrial. Em temas relacionados com a investigação do processamento vidreiro industrial, a prática de desenvolver trabalho experimental integrado no próprio ambiente industrial está claramente documentada na bibliografia publicada em revistas e jornais de referência internacional. ABSTRACT: The research on the causes of major defects that occur in glass tableware products produced by automatic processes and the development of new glasses and technologies for increasing the production efficiency, or the flexibility of operation were the objectives of the Thesis project. Viscosity influences the flexibility of glass forming. Lower drop temperatures, high product wall thicknesses, or low areas of heat transfer facilitate the occurrence of defects, mainly mechanical and surface born. We identified the products of glass tableware showing the greatest difficulties in forming, designated as complex shape products. The effect of the amount of recycled glass used in the preparation of glass batches on the conformation of products of complex shapes and on glass workability is discussed. The amount of recycled glass affects the volatilization of glass modifiers which in turn have an effect on the glass properties and workability. New glasses which become compatible with the use of oxygen burners were formulated, tested and developed to the industrial use, oxygen enrichment being used to reduce the mechanical and surface defects in pressed glass tableware. Compatibility glass / technology was achieved with a modified system of tuning of the glass. The modified glasses have physical and chemical properties similar to the original glass and therefore are commercially viable. The technology of the colouring channels was used to change glass workability of a glass base by the introduction of up to 5 % Li2O rich in colourless frit. The values of RMS (relative machine speed) fell from 106.8 % to 95.7 % while the values of Pt (cooling time) increased from 100.6 s to 111.3 s by the introduction of glass frits. The physico-chemical properties of the modified glass show commercial viability. This technology introduces flexibility in industrial processes of glass. The chemical composition of glass and therefore the properties related to workability can be understood as another variable of the glass forming processes and used according to the available forming techniques, the shape of objects and the engineering tools used for the moulds. Convergence was observed between experimental and predicted from Huff and Fluegel models in studying the properties of glasses. An important part of this work was done inside the industrial environment. On issues related to the investigation of the glass processing inside the industry, the practice of developing experimental work integrated in the industrial environment is clearly documented and referenced in the published literature in international journals and periodicals.

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Catalog and promotional literature for R. Wallace & Sons Manufacturing Co., manufacturers of silver tableware.

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Mode of access: Internet.

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This research is concerned with the relationship between business strategy and the environment within traditional sectors. It has sought to learn more about the strategic environmental attitudes of SMEs compared with large companies operating under the same market conditions. The sector studied is the ceramics industry (including tableware & ornamental-ware, sanitary ware & tiles, bricks, industrial & advanced ceramics and refractories) in the UK and France. Unlike the automotive, oil, chemical, steel or metal processing sectors, this industry is one of the few industrial sectors which has rarely been considered. The information on this sector was gathered by interviewing people responsible for environmental issues. The actual programme of valid interviews represents approximately a quarter of the UK and French ceramics industry which is large enough to enable a quantitative analysis and significant and non-biased conclusions. As a whole, all companies surveyed agreed that the ceramics activity impacts on the environment, and that they are increasingly affected both by environmental legislation, and by various non-legislative pressures. Approaches to the environmental agenda differ significantly among large and small companies. Smaller companies feel particularly pressed both by the financial costs and management time required to meet complex and changing legislation. The results of this survey also suggest that the ceramics industry sees environmental issues in terms of increased costs rather than new business opportunities. This is due principally to fears of import substitution from countries with lower environmental standards. Finally, replies indicate that generally there is a low level of awareness of the current legislative framework, suggesting a need to shift from a regulatory approach to a more self-regulated approach which encourages companies to be more proactive

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Drying is an important unit operation in process industry. Results have suggested that the energy used for drying has increased from 12% in 1978 to 18% of the total energy used in 1990. A literature survey of previous studies regarding overall drying energy consumption has demonstrated that there is little continuity of methods and energy trends could not be established. In the ceramics, timber and paper industrial sectors specific energy consumption and energy trends have been investigated by auditing drying equipment. Ceramic products examined have included tableware, tiles, sanitaryware, electrical ceramics, plasterboard, refractories, bricks and abrasives. Data from industry has shown that drying energy has not varied significantly in the ceramics sector over the last decade, representing about 31% of the total energy consumed. Information from the timber industry has established that radical changes have occurred over the last 20 years, both in terms of equipment and energy utilisation. The energy efficiency of hardwood drying has improved by 15% since the 1970s, although no significant savings have been realised for softwood. A survey estimating the energy efficiency and operating characteristics of 192 paper dryer sections has been conducted. Drying energy was found to increase to nearly 60% of the total energy used in the early 1980s, but has fallen over the last decade, representing 23% of the total in 1993. These results have demonstrated that effective energy saving measures, such as improved pressing and heat recovery, have been successfully implemented since the 1970s. Artificial neural networks have successfully been applied to model process characteristics of microwave and convective drying of paper coated gypsum cove. Parameters modelled have included product moisture loss, core gypsum temperature and quality factors relating to paper burning and bubbling defects. Evaluation of thermal and dielectric properties have highlighted gypsum's heat sensitive characteristics in convective and electromagnetic regimes. Modelling experimental data has shown that the networks were capable of simulating drying process characteristics to a high degree of accuracy. Product weight and temperature were predicted to within 0.5% and 5C of the target data respectively. Furthermore, it was demonstrated that the underlying properties of the data could be predicted through a high level of input noise.

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The intention of this thesis, “Ceramics in Britain (1840–90): Meanings and Metaphors” is to present new approaches for interpreting ceramics in nineteenth-century Britain by situating, problematizing, and contextualizing pottery and porcelain in the popular debates of the day within the methodologies of material culture, design, cultural and art histories. I ask how did ceramics—portable, functional, and often decorative objects—contribute to shaping modes of experiences? Crockery, tableware and blue-white-porcelain, admittedly largely mediated in texts and paintings, are at the centre of this research to examine how they imposed symbolism and influenced the engagement of their subjects beyond their intended meanings and functions. This thesis tracks a common rhetoric shared by writers and artists across genres and understood by readers and viewers: crockery in the cupboard, on the mantel, the table or the floor were popular motifs exemplifying class, gender, character, etiquette, and taste. This thesis also seeks to map ceramics’ relations with other objects and people depicted. Their meanings and metaphors changed, depending on their exchange with other objects in the room and who uses them. The conventions of representing ceramics dictated a particular grammar that writers and artists used, critiqued, discarded or personalized. The examination of ceramics mediated in text and image especially in comparison with extant objects invites a deeper probing of both material culture and artistic practice, which helps to situate the agency of the ceramic objects themselves. Also this thesis, in attempt to explore new methodological approaches for ceramic studies, examines the social life of the mid-Victorian relief-moulded “Minster” Jug in the Gardiner Museum in Toronto. The product originating in Staffordshire in 1843 and exported to the colonies holds significance due to its multiple life histories. Viewing the “Minster” through the lenses of curator, collector, consumer, and critic its layered lives unfold to reveal the protocols of museum praxis as well as important aspects of mid-nineteenth-century British society related to design reform, gender, imperialism and consumption patterns. This thesis contends that the British experienced ceramics in sometimes unexpected ways, unrelated to their original purpose, such as tools of violence or containers of solace, and transformative fantasy.

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Se evalúa si una sola extracción, mediante la aplicación de un método de ensayo normalizado que simula condiciones extremas de uso, permite determinar el contenido total de plomo y cadmio presente en piezas de vajilla cerámica que entran en contacto con los alimentos y su implicación en el resultado analítico. Se aplicó el método de ensayo varias veces sobre materiales de referencia de cerámica con diferentes concentraciones iniciales de plomo y el cadmio para cuantificar la liberación sucesiva de ambos metales. El lixiviado en cada aplicación se analizó por absorción atómica. Los resultados mostraron que una sola aplicación del método de ensayo no extrae todo el plomo y el cadmio en la vajilla cerámica. Se observaron liberaciones posteriores para todas las piezas de cerámica a prueba con diferente concentración inicial. Para cadmio se registraron las siguientes variaciones en las extracciones: 40 a 95% en la primera extracción, de 0 a 28% en la segunda, de 0.2 hasta 21% en la tercera, y de 1 a 40% en la cuarta. Para el plomo, se registraron los subsiguientes valores en los lixiviados entre el 50 y el 93% en la primera prueba, entre el 2 y el 24% en la segunda, entre el 2 y el 18% en la tercera y entre el 2 y el 17% en la cuarta extracción. Los resultados revelan que la cantidad total de plomo y cadmio liberado en una sola prueba estándar no reflejan el contenido total de plomo y cadmio que las piezas de cerámica liberan a largo plazo después de su uso.