748 resultados para Explosion.
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We used a novel system of three continuous wave Doppler radars to successfully record the directivity of i) Strombolian explosions from the active lava lake of Erebus volcano, Antarctica, ii) eruptions at Stromboli volcano, Italy, and iii) a man-made explosion in a quarry. Erebus volcano contains a convecting phonolite lava lake, presumably connected to a magma chamber at depth. It is one of the few open vent volcanoes that allow a direct observation of source processes during explosions. Its lava lake is the source of frequent violent Strombolian explosions, caused by large gas bubbles bursting at the lake surface. The exact mechanism of these bubble bursts is unclear, as is the mechanism of the creation of the infrasound signal accompanying the explosions. We use the Doppler radar data to calculate the directivity of Strombolian eruptions at Erebus. This allows us to derive information about the expected type of infrasound source pattern (i.e. the role of a dipole in addition to the monopole signature) and the physical structure of the volcano. We recorded 10 large explosions simultaneously with three radars, enabling us to calculate time series of 3D directivity vectors (i.e. effectively 4D), which describe the direction of preferred expansion of the gas bubble during an explosion. Such directivity information allows a comparison to dipole infrasound radiation patterns recorded during similar explosions only a few weeks later. Video observations of explosions support our interpretation of the measurements. We conclude that at Erebus, the directivity of explosions is mainly controlled by random processes. Since the geometry of the uppermost conduit is assumed to have a large effect on the directivity of explosions, the results suggest a largely symmetrical uppermost conduit with a vertical axis of symmetry. For infrasound recordings, a significant dipole signature can be expected in addition to the predominant monopole signature.
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National Highway Safety Bureau, Washington, D.C.
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At head of title: Engineering and design.
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The Breslau arts scene during the Weimar period was one of the most vibrant in all of Germany, yet it has disappeared from memory and historiography. Breslau was a key center for innovative artistic production during the Weimar Republic; recovery of its history will shed new light on German cultural dynamics in the 1920s. Such a study has art historical significance because of the incredible extent of innovation that occurred in almost every intellectual field, advances that formed the basis for aesthetic modernism internationally and continue to affect the course of visual art and architecture today. Architecture education, just one example in many, is still largely based on a combination of the Bauhaus model from the 1920s and the model developed at the Breslau Academy of Fine and Applied Art. The exploratory attitude encouraged in Weimar era arts endeavors, as opposed to the conformism of academic art, is still a core value promoted in contemporary art and architecture circles. Given the long-lasting influence of Weimar culture on modernism one would expect to find a spate of studies examining every aspect of its cultural production, but this is not the case. Recent scholarship is almost exclusively focused on Berlin and the Dessau Bauhaus. Although both interests are understandable, the creative explosion was not confined to these cities but was part of a larger cultural ethos that extended into many of the smaller regional centers. The Expressionist associations the Blaue Reiter in Munich and Brücke in Dresden are two well-known examples. Equally, innovation was not confined to a few monumental projects like the Stuttgart Weissenhofsiedlung but part of a broader national cultural ethos. The dispersion of modernism occurred partly because of the political history of Germany as a loosely joined confederation of small city states and principalities that had strong individual cultural identities before unification in 1871 but also because of the German propensity to value and take intense pride in the Heimat, understood both as the hometown and the region. Heimatliebe translated into generous support for cultural institutions in outlying cities. Host to a roster of internationally acclaimed artists and architects, major collectors, arts organizations, museums, presses, galleries, and one of the premier German arts academies of the day, Breslau boasted a thriving modern arts scene until 1933 when the Nazis began their assault on so-called "degenerate" art. This book charts the cultural production of Breslau-based artists, architects, art collectors, urban designers, and arts educators, who were especially interesting because they operated in the space between the margins of Weimar-era cultural debates. Rather than accepting the radical position of the German avant-garde or the reactionary position of German conservatives, many Breslauers sought a middle ground. It is the first book in English to address this history and presents the history in a manner unique to any studies currently on the market. 'Beyond the Bauhaus' explores the polyvalent and contradictory nature of cultural production in Breslau in order to expand the cultural and geographic scope of Weimar history; the book asserts a reciprocal dimension to the relationship between regional culture and national culture, between centers like Breslau and the capital Berlin. With major international figures like the painters Otto Mueller and Oskar Moll, architects Hans Scharoun and Adolf Rading, urban planners Max Berg and Ernst May, collectors Ismar Littmann and Max Silberberg, and an art academy that by 1929 was considered the best in Germany, Breslau clearly had significance to narratives of Weimar cultural production. 'Beyond the Bauhaus' contributes the history of German culture during the Weimar Republic. It belongs alongside histories of art, architecture, urban design, exhibition, collecting, and culture; histories of the Bauhaus; histories of arts education more broadly; and German history. The readership would include those interested in German history; German art, architecture, urban design, planning, collecting, and exhibition history; in the avant-garde; the development of arts academies and arts pedagogy; and the history of Breslau and Silesia.
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Carbon nanotubes (CNT) are well-ordered, high aspect ratio allotropes of carbon. The two main variants, single-walled carbon nanotubes (SWCNT) and multi-walled carbon nanotubes (MWCNT) both possess a high tensile strength, are ultra-light weight, and have excellent chemical and thermal stability. They also possess semi- and metallic-conductive properties. This startling array of features has led to many proposed applications in the biomedical field, including biosensors, drug and vaccine delivery and the preparation of unique biomaterials such as reinforced and/or conductive polymer nanocomposites. Despite an explosion of research into potential devices and applications, it is only recently that information on toxicity and biocompatibility has become available. This review presents a summary of the performance of existing carbon biomaterials and gives an outline of the emerging field of nanotoxicology, before reviewing the available and often conflicting investigations into the cytotoxicity and biocompatibility of CNT. Finally, future areas of investigation and possible solutions to current problems are proposed. (c) 2005 Elsevier Ltd. All rights reserved.
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From the break up of the New Left into single issue groups at the end of the 1960s came a variety of groups representing the peace movement, environmental movement, student movement, women’s movement, and gay liberation movement. This explosion of new social movement activism has been heralded as the age of new radical politics. Many theorists and activists understand new social movements, as replacing the working class as an agent for progressive social change. Scholars and activists now alike debate the possibilities for revolutionary change in this era of multinational capitalism and new nationalisms. This paper examines some of the above claims in the context of the contemporary Serbian civil society. It explores the relationship between the civil society, activism, and narratives in Serbia. In particular, it examines the anti-Milosevic’ movement Otpor! (Resistance), and its discourse, practice and politics in public spaces, through an analysis of narratives of a set of roughly 20 interviews with Otpor! activists, aged 18-35. In the following discussion, then, I will focus on some of the particular dilemmas of contemporary Serbian popular movements - they are dilemmas to do with the growing complexity of media life in the Serbian spaces. I ground my debate on particular uses of the notion of civil society in the narratives of Otpor! activists, while I focus on the question of how do Otpor! activists relate to Leftist/radical politics and the idea of civil society.
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The optimum bandwidth for shallow, high-resolution seismic reflection differs from that required for conventional petroleum reflection. An understanding of this issue is essential for correct choice of acquisition instrumentation. Numerical modelling of simple Bowen Basin coal structures illustrates that, for high-resolution imaging, it is important to accurately record all frequencies up to the limit imposed by earth scattering. On the contrary, the seismic image is much less dependent on frequencies at the lower end of the spectrum. These quantitative observations support the use of specialised high-frequency geophones for high-resolution seismic imaging. Synthetic seismic inversion trials demonstrate that, irrespective of the bandwidth of the seismic data, additional low-frequency impedance control is essential for accurate inversion. Inversion provides no compelling argument for the use of conventional petroleum geophones in the high-resolution arena.
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Esta tese analisa o papel dos líderes da Igreja católica institucionalizada antes e durante o movimento e guerra do Contestado de 1912 a 1916. Movimento classificado como messiânico-milenarista ocorrido no sul do Brasil numa área litigiosa pleiteada pelos Estados do Paraná e Santa Catarina. Aponta o contexto sócio-econômico-político e religioso que criou condições para que o movimento pudesse emergir. Analisa a formação do catolicismo rústico popular brasileiro e suas expressões na região do Contestado, destacando-se o papel dos monges. Aprofunda a compreensão do catolicismo oficial em processo de romanização e do papel dos frades franciscanos, de suas concepções e práticas na tentativa de enquadrar a religião cabocla dentro dos princípios da reforma. Analisa a reação cabocla diante das mudanças implantadas na região e a explosão da irmandade, denominada Terra Santa , que buscava efetivar uma nova ordem . Aprofunda especialmente o papel dos frades representantes da Igreja católica, tendo em vista dispersar e pacificar o caboclo rebelde e a aliança, que estabeleceram com as forças repressoras, para implantar a ordem e a paz na região contestada, com a conseqüente eliminação radical da irmandade cabocla e de seus redutos .(AU)
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Este trabalho analisa sociologicamente na contemporaneidade o campo imagético na música gospel e de que forma, este influencia na mudança dos paradigmas imagético - estéticos utilizados pelas produtoras fonográficas em seu marketing religioso para a comercialização da música gospel no mercado da música evangélica brasileira, proporcionando neste modelo atual um crescimento qualitativo e quantitativo dos produtos destinados ao público evangélico. A pesquisa identifica nas produções visuais de divulgação e comercialização de CDs, DVDs, sites das produtoras fonográficas, feiras e premiações musicais, os mecanismos utilizados para a construção de um novo paradigma imagético que proporciona no campo religioso, o surgimento de um novo imaginário evangélico mimeticamente construído para alimentar um mercado gospel fomentado pela tríade social: espetáculo, consumo e entretenimento. Desta forma, a analise tem o seu recorte nas mudanças paradigmáticas que surgem a partir dos primeiros cantores e cantoras da década de 1950 até culminar na explosão da música gospel no início da década de 1990.(AU)
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Recently, we have seen an explosion of interest in ontologies as artifacts to represent human knowledge and as critical components in knowledge management, the semantic Web, business-to-business applications, and several other application areas. Various research communities commonly assume that ontologies are the appropriate modeling structure for representing knowledge. However, little discussion has occurred regarding the actual range of knowledge an ontology can successfully represent.