340 resultados para porcelain stoneware
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"This edition is limited to 1,500 copies, of which this is no. 1015."
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"Selected list of works on porcelain": p. xxvi-xxxii.
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Bibliography: p. xiii-xvi.
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Mode of access: Internet.
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We compare the trace element and Sr isotopic compositions of stoneware bodies made in Yaozhou and Jizhou to characterise these Chinese archaeological ceramics and examine the potential of Sr isotopes in provenance studies. Element concentrations determined by ICP-MS achieve distinct characterisation for Jizhou samples due to their restricted variation, yet had limited success with Yaozhou wares because of their large variability. In contrast, Sr-87/Sr-86 ratios in Yaozhou samples have a very small variation and are all significantly lower than those of Jizhou samples, which show a large variation and cannot be well characterised with Sr isotopes. Geochemical interpretation reveals that Sr-87/Sr-86 ratios will have greater potential to characterise ceramics made of low Rb/Sr materials such as kaolin clay, yet will show larger variations in ceramics made of high Rb/Sr materials such as porcelain stone. (c) 2005 Elsevier B.V. All rights reserved.
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Materiais compósitos restauradores representam um dos mais bem sucedidos biomateriais na pesquisa moderna, na substituição do tecido biológico em aparência e função. Nesta linha, a porcelana feldspática tem sido largamente usada em odontologia devido suas interessantes qualidades como estabilidade de cor, propriedades estéticas, elevada durabilidade mecânica, biocompatibilidade, baixa condutividade térmica e elevada resistência ao desgaste. Entretanto, este material é frágil e pode falhar em ambiente oral devido ao micro-vazamento, baixa resistência à tração, descolagem ou fratura. Assim, para melhorar as propriedades mecânicas da porcelana, a zircônia parcialmente estabilizada com Ítria (Y-TZP) pode ser uma boa alternativa para fortalecer e produzir infraestruturas totalmente cerâmicas (coroas e próteses parciais fixas). Portanto, este estudo tem por objetivo avaliar as propriedades mecânicas e características microestruturais da porcelana reforçada com zircônia (3Y-TZP) em diferentes conteúdos e as variáveis que afetam as propriedades mecânicas destes materiais. O estudo de caracterização revelou que a zircônia comercial apresenta melhores resultados quando comparada com a zircônia sintetizada pelo CPM. Assim, os estudos seguintes utilizaram a zircônia comercial para todos os testes requeridos. As partículas de zircônia apresentam elevadas propriedades mecânicas quando comparadas a zircônia aglomerada. Os diferentes conteúdos revelam que as propriedades mecânicas dos compósitos aumentam com o aumento do conteúdo volumétrico até 30% vol.% (198,5Mpa), ou seja, maior resistência à flexão quando comparada com os outros compósitos. Do mesmo modo, a resistência ao desgaste para os compósitos com (30%, vol.% de zircônia) apresenta valores superiores quando comparado aos demais compósitos. Na adesão cerâmico-cerâmico a porcelana exibe elevada adesão para a superfície de zircônia porosa quando comparada a superfície rugosa. Os furos superficiais (PZ) e aplicação de compósitos com camada intermediária (RZI) na zircônia causam separadamente uma melhoria da resistência ao cisalhamento da zircônia-porcelana quando comparados as amostras convencionais de zircônia-porcelana (RZ), embora não sejam estatisticamente significativas (p>0.05). A presença de uma camada intermediaria produz um aumento significativo na força de ligação (~55%) em relação as amostras convencionais (RZ). Portanto, a correta a correta configuração e tratamento superficial podem produzir subestruturas com qualidade e força de ligação adequadas aos requisitos odontológicos.
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The dielectric porcelain is usually obtained by mixing various raw materials proportions and is used in the production of electronic equipment for various applications, from capacitors of high and low Power to insulators for low, medium, high and extra high voltage, which are used in distribution lines and transmission of electricity.This work was directed to the s tudy of technological properties of technic porcelain, made from raw materials extracted from pegmatites found in the regions of Seridó and the Alto Oeste of Rio Grande do Norte, which are made of kaolin, quartz and feldspar, abundant and high quality in these regions. The technic ceramics were obtained by mixing in appropriate levels, kaolin, feldspar, quartz and clay, the last item from a pottery in the city of Sao Gonçalo do Amarante, Rio Grande do Norte. During the development the following characterizations correlated to raw materials were made: laser particle sizing, x-ray diffraction, DTA and TG. The compositions studied were formed by uniaxial pressing at a pressure of 50 MPa and sintered at temperatures ranging from 1150 to 1350ºC and levels (times) of sintering between 30, 60, 90 and 120 minutes. The characterization of the samples were taken from the analysis of weight loss, linear shrinkage, porosity, stoneware curve, bulk density, flexural strength of three points, SEM and X-ray diffraction, TMA, Dielectric and cross Resistivity. The studied materials can be employed in producing the objects used in electrical engineering such as: insulators for low, medium and high-voltage electrical systems, command devices, bushing insulation for transformers, power capacitors, spark plugs, receptacles for fluorescent and incandescent light bulbs and others
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Composite polymer insulators provide many advantages over the traditional porcelain insulators and they are increasingly being used at both transmission and distribution levels. In the present paper, an epoxy resin/silica nanocomposite dielectric material (NDM) structure is proposed and fabricated. Hydrophobic fumed silica is incorporated in epoxy resin matrix and acetone is adopted as media agent to effectively achieve homogenous dispersion of the nano-scale silica filler. The acetone also acts as diluents to reduce viscosity before the curing phase of epoxy resin and enables bubbles to escape from being trapped. Through partial discharge (PD) and surface aging tests, it is illustrated that the inception of surface discharge of the proposed NDM is relatively higher than that of the non-filled counterpart, and a better PD resistivity was observed in the negative half cycle regarding to applied AC voltage. Results of surface aging test indicate that surface discharge activity is retarded over the test conducting time. By contrast, surface discharge developed to the opposite way on the non-filled sample. Therefore, the proposed NDM could provide better safety reliability and lower maintenance cost to industrial application compared with nonfilled conventional epoxy resin.
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Seven photographic reproductions of a white porcelain ceremonial drinking cup used circa 1715 by the local Chevra Kadisha (burial society) in Eisenstadt, Austria, with Hebrew text and depictions of a Jewish funeral around the circumference.
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A frieze-like composition depicting storefronts with mixed English and Chinese language signs, as well as activities of shopkeepers and shoppers.
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Two cups and two saucers used for chocolate. The Einstein children's portraits are emblazoned on these delicate teacups, presumably by their parents, as these come from the family collection.
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Revolution at home! Visual Changes in Everyday Life in Finland in the Late 1960s and Early 1970s The purpose of my research was to investigate the visual changes in private homes in Finland during the 1960s and 1970s. The 1960s is often described as a turning point in Finnish life, a time when the society's previous agricultural orientation began to give way first to an industrial orientation and then, by the end of the 1970s, to a service orientation. My title refers to three elements in the transition period: the question of daily life; the timeframe; and the visual changes observable in private homes, which in retrospect signalled a kind of revolution in the social orientation. Those changes appeared not only in colours and designs but also in the forms and materials of household objects. My premise is that analysing interiors from a historical perspective can reveal valuable information about Finnish society and social attitudes, information that might easily escape attention otherwise. I have used the time-honoured method of collecting narratives. As far back as Aristotle, formulating narratives has been a means of gaining knowledge. By collecting and classifying narratives about the 1960s and 1970s, it is possible to gain new insight into these important decades. The archetypal 1960s narrative, involving student demonstrations and young people's efforts to improve society, is well known. Less well known is the narrative that relates the changes going on in daily life. Substantially the study focuses mainly on fabrics, porcelain ware and the use of plastics. Marimekko's style is especially important when following innovations in the 1950s, 1960s and 1970s. Porcelain production at the Arabia factory was another element that had a great influence on the look of Finnish homes and kitchens; and a further widespread phenomenon of the late 1960s and early 1970s was the use of plastics in many different forms. Further evidence was sought in Anttila department store mail catalogues, which displayed products that were marketed on a large scale, as well as in magazines such as Avotakka. The terminal point of the visual evolution is the real homes, as seen in the questionnaire "Homemade". I have used the 800 pages of the oral history text that respondents of the Finnish Literature Society have written about their first home in the 1960s. I also used archival material on actual homes in Helsinki from the archives of the Helsinki City Museum. The basic story is the elite narrative, which was produced by students in the 1960s. My main narrative from the same time is visual change in everyday life in the late 1960s and early 1970s. I have classified the main narrative of visual change into four subcategories: the narrative of national ideas, the narrative of a better standard of living, the narrative of objects in the culture of everyday life and the narrative of changing colour and form.
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Transmission of bulk power at high voltages over very long distances has become very imperative. At present, throughout the globe, this task has been mostly performed by overhead transmission lines. The dual task of mechanically supporting and electrically isolating the live phase conductors from the support tower is performed by string insulators. Whether in clean condition or under polluted conditions, the electrical stress distribution along the insulators governs the possible flashover, which is quite detrimental to the system. However, a reliable data on stress distribution in commonly employed string insulators are rather scarce. Considering this, the present work has made an attempt to study accurately, the field distribution in 220 kV strings for six different types of porcelain/ceramic insulators (Normal and Antifog discs) used for high voltage transmission. The surface charge simulation method is employed for the required field computation. Voltage and electric stress distribution is deduced and compared across different types of discs. A comparison on normalised surface resistance, which is an indicator for the stress concentration under polluted condition, is also attempted.