180 research outputs found

    Comparing resonant photon tunneling via cavity modes and Tamm plasmon polariton modes in metal-coated Bragg mirrors

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    Resonant photon tunneling was investigated experimentally in multilayer structures containing a high-contrast (TiO2/SiO2) Bragg mirror capped with a semitransparent gold film. Transmission via a fundamental cavity resonance was compared with transmission via the Tamm plasmon polariton resonance that appears at the interface between a metal film and a one-dimensional photonic bandgap structure. The Tamm-plasmon-mediated transmission exhibits a smaller dependence on the angle and polarization of the incident light for similar values of peak transmission, resonance wavelength, and finesse. Implications for transparent electrical contacts based on resonant tunneling structures are discussed

    Glass Ceramic Waste Forms for Combined CS+LN+TM Fission Products Waste Streams

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    In this study, glass ceramics were explored as an alternative waste form for glass, the current baseline, to be used for immobilizing alkaline/alkaline earth + lanthanide (CS+LN) or CS+LN+transition metal (TM) fission-product waste streams generated by a uranium extraction (UREX+) aqueous separations type process. Results from past work on a glass waste form for the combined CS+LN waste streams showed that as waste loading increased, large fractions of crystalline phases precipitated upon slow cooling.[1] The crystalline phases had no noticeable impact on the waste form performance by the 7-day product consistency test (PCT). These results point towards the development of a glass ceramic waste form for treating CS+LN or CS+LN+TM combined waste streams. Three main benefits for exploring glass ceramics are: (1) Glass ceramics offer increased solubility of troublesome components in crystalline phases as compared to glass, leading to increased waste loading; (2) The crystalline network formed in the glass ceramic results in higher heat tolerance than glass; and (3) These glass ceramics are designed to be processed by the same melter technology as the current baseline glass waste form. It will only require adding controlled canister cooling for crystallization into a glass ceramic waste form. Highly annealed waste form (essentially crack free) with up to 50X lower surface area than a typical High-Level Waste (HLW) glass canister. Lower surface area translates directly into increased durability. This was the first full year of exploring glass ceramics for the Option 1 and 2 combined waste stream options. This work has shown that dramatic increases in waste loading are achievable by designing a glass ceramic waste form as an alternative to glass. Table S1 shows the upper limits for heat, waste loading (based on solubility), and the decay time needed before treatment can occur for glass and glass ceramic waste forms. The improvements are significant for both combined waste stream options in terms of waste loading and/or decay time required before treatment. For Option 1, glass ceramics show an increase in waste loading of 15 mass % and reduction in decay time of 24 years. Decay times of {approx}50 years or longer are close to the expected age of the fuel that will be reprocessed when the modified open or closed fuel cycle is expected to be put into action. Option 2 shows a 2x to 2.5x increase in waste loading with decay times of only 45 years. Note that for Option 2 glass, the required decay time before treatment is only 35 years because of the waste loading limits related to the solubility of MoO{sub 3} in glass. If glass was evaluated for similar waste loadings as those achieved in Option 2 glass ceramics, the decay time would be significantly longer than 45 years. These glass ceramics are not optimized, but already they show the potential to dramatically reduce the amount of waste generated while still utilizing the proven processing technology used for glass production

    O circuito social da fotografia em Porto Alegre (1922 e 1935)

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    Photography has been increasingly investigated by Brazilian historians, thus bringing about diverse methodological approaches for the analysis of such visual images. A fundamental component in the studies of this nature is research on photographys social circuit. Within this scope, there is a body of information that is related to the production, circulation and use of photography understood as a visual, creative and disseminating image for certain social imaginaries, and as an artifact that had a place in peoples lives in different contexts. In this article, the author investigates photographys social circuit in the city of Porto Alegre in the 1920s and 1930s, in an attempt to find clues of the presence of this modern invention in the life of Porto Alegre citizens and of the urban vistas that it disseminated

    O manuscrito e o iconográfico em cartões-postais belicosos: da apologia cavalheiresca à contestação da Grande Guerra (1914-1918) na França

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    O trabalho analisa mensagens transmitidas por cartões-postais produzidos e circulados na França no contexto da Primeira Guerra Mundial (1914-1918), apresentando temática associada ao conflito. O objetivo é contrapor as mensagens iconográficas e textuais neles impressas à quelas que foram manuscritas por seus remetentes, de modo a evidenciar formas de expressão e percepções do conflito, conforme empregadas por civis e militares, em diferentes momentos de seu desenvolvimento.The paper analyzes messages conveyed by postcards produced and circulated in France during the First World War (1914-1918), with themes referring to the conflict. The intention is to compare the iconographic and textual messages printed with handwritten messages, to display forms of expression and perception of war, used by civilian and military on different occasions

    Nos caminhos da Luz, antigos palacetes da elite paulistana

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    The present article is dedicated to recover the memory of the old mansions built in\ud the region of Luz Railway Station, from the beginning of the second half of the 19th Century\ud onwards. It was around that time that the region became São Paulo elites first residential\ud neighbourhood, concentrating mansions that expressed the local elaborations of architectural\ud Neo-classicism and Eclecticism. One intends to approach the interpretation processes that\ud characterised such architectural production

    Bem-morar em São Paulo, 1880-1910: Ramos de Azevedo e os modelos europeus

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    Domestic architecture achieves a great impulse in the second half of XIXth-century. From Europe to the whole world, models are conformed to the new social order and spread as industrialization takes command. Dwelling becomes the main concern among architects. New concepts are developed for the ideal house for 011 social strata: working class, middle-class, bourgeoisie. This essay traces the introduction in São Paulo of European formal patterns and principies Ihygiene, salubrity, comfort, social and domestic rites, social visibility) through the activity of F. P. Ramos de Azevedo! 1851-19281. The main projects he conceived for the local bourgeoisie are analysed.A arquitetura doméstica tem um grande impulso no século XIX. Da Europa são difundidos, para todo mundo, os modelos conformados à nova ordem social e à industrialização. A residência se transforma numa preocupação central dos arquitetos. Desenvolvem-se novos conceitos para casa ideal para todas as camadas sociais: operários, classe média, burguesia. Este artigo retrata, em São Paulo, a introdução de padrões formais e princípios (de higiene, salubridade, conforto, ritos sociais e domésticos, as aparências). a partir da atividade de F. P. Ramos de Azevedo (1851-19201. Analisam-se os principais projetos que ele desenvolveu para a burguesia local
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