The nature of motions in intense magnetic fields is investigated. For a flux tube in a uniform atmosphere a dispersion relation is derived for the modes of vibration and analytic approximations are obtained for a slender tube. In a stratified atmosphere an expansion procedure is used to derive an equation for the vertical velocity perturbation. The behaviour of motions within the flux tube is shown to depend upon a transition frequency ω_v such that vertically propagating waves are possible only for frequencies greater than ω_v. Also, the nature of convective instability in a slender magnetic flux tube is explored. A sufficient condition for stability is derived for the case of an arbitrary temperature profile in the external medium. For a tube of infinite depth, with a uniform-temperature gradient inside the tube equal to that in the exterior, a necessary and sufficient condition for convective stability to occur inside the tube is derived. Under the assumptions of the model, intense flux tubes are convectively stable if sufficiently shallow (with depths 1 - 2 x 10³ km or less). Tubes that extend deeper into the convection zone are potentially (convectively) unstable, but may be stabilised for sufficiently strong magnetic fields. Radiative damping of waves is important in the upper photosphere and the effect of radiative relaxation on the propagation of waves in an intense flux tube is examined both for a uniform and stratified atmosphere. The cut-off frequency is generalized to include the effects of radiative relaxation. The phase-shift between velocity oscillations at two different levels and the phase difference between temperature and velocity perturbations are derived and compared with the available observations. Finally, the consequences of the observed steady downflow are discussed.

The concept of status crystallization (Lenski: 1954) considers, simultaneously, the influence which status rankings on the education, occupation, and income hierarchies exert on the individual. Incongruent rankings on various status dimensions are thought to predispose an individual to a number of select reactions, most notably, the expression of political extremism and the desire for social change. In addition, past research suggests that voluntary association membership may serve as an integrative mechanism at both the social psychological and the sociological levels. The relationship between the nature of the status inconsistency experienced and the expression of liberal and/or conservative political and economic ideologies was examined, with the expectation that educational level would be the most crucial determinant of political ideology and income, of economic ideology. As well, the nature of the relationship between membership in instrumental voluntary associations and status inconsistency was investigated. Structured interviews were administered to respondents via telephone communication. The McClosky scale of conservatism (1958) and the Laumann scale of economic liberalism (1966) were employed to determine the relationship between the type of inconsistency experienced and the expression of liberal or conservative ideologies. Analysis of the data failed to reveal statistically significant results. The relationship between inconsistency and the expression of an extreme ideology was not altered when the nature of the inconsistency was examined. As well, there was no difference between status consistent and inconsistent respondents with respect to the number of instrumental voluntary association memberships reported. / M.S.

In this thesis I investigate the implications, for one's account of mathematics, of holding an anti-realist view. The primary aim is to appraise the scope of revision imposed by anti-realism on classical inferential practice in mathematics. That appraisal has consequences both for our understanding of the nature of mathematics and for our attitude towards anti-realism itself. If an anti-realist position seems inevitably to be absurdly revisionary then we have grounds for suspecting the coherence of arguments canvassed in favour of anti-realism. I attempt to defend the anti-realist position by arguing, i) that it is not internally incoherent for anti-realism to be a potentially revisionary position, and ii) that an anti-realist position can, plausibly, be seen to result in a stable intuitionistic position with regard to the logic it condones. The use of impredicative methods in classical mathematics is a site of traditional intuitionistic attacks. I undertake an examination of what the anti-realist attitude towards such methods should be. This question is of interest both because such methods are deeply implicated in classical mathematical theory of analysis and because intuitionistic semantic theories make use of impredicative methods. I attempt to construct the outlines of a set theory which is anti-realistically acceptable but which, although having no antecedent repugnance for impredicative methods as such, appears to be too weak to offer an anti-realistic vindication of impredicative methods in general. I attempt to exonerate intuitionistic semantic theories in their use of impredicative methods by showing that a partial order relying on the nature of our grasp of the intuitionistic meaning stipulations for the logical constants precludes a possible circularity.

VAZ,G.L. O. Eletrodeposição, Caracterização e Estudos de Corrosão de Revestimentos de Ni-Mo e Ni-W 2007. 85 f. Dissertação (Mestrado em Ciências) – Centro de Ciências , Universidade Federal do Ceará, Fortaleza, 2007. / Submitted by irlana araujo (irlanaaraujo@gmail.com) on 2011-12-14T18:55:54Z No. of bitstreams: 1 2007dis_Gust_Vaz.pdf: 5262736 bytes, checksum: 7e10de74f24375b9e91a9301ceb635b7 (MD5) / Approved for entry into archive by Aline Nascimento(vieiraaline@yahoo.com.br) on 2011-12-19T14:50:29Z (GMT) No. of bitstreams: 1 2007dis_Gust_Vaz.pdf: 5262736 bytes, checksum: 7e10de74f24375b9e91a9301ceb635b7 (MD5) / Made available in DSpace on 2011-12-19T14:50:29Z (GMT). No. of bitstreams: 1 2007dis_Gust_Vaz.pdf: 5262736 bytes, checksum: 7e10de74f24375b9e91a9301ceb635b7 (MD5) Previous issue date: 2007-02-05 / The corrosion behavior and mechanical properties of Ni-Mo and Ni-W electrocoatings in NaCl solutions are investigated in this work. A comparative study has been done with the properties of Cr. All electrocoatings were obtained under galvanostatic control at room temperature and were evaluated in terms of composition, microstructure, microhardness, cristalinity and corrosion resistance. The surface morphology was characterized by scanning electron microscopy (SEM), the chemical composition was determined by energy dispersive X-rays (EDX), the microhardness was measured by the Vickers hardness test and the structure was determined by X-ray diffraction (DRX). The electrochemical corrosion tests were carried out by linear potenciodinamic polarization (PP) and electrochemical impedance spectroscopy (EIS). The results showed that Ni-Mo and Ni-W present good corrosion resistance when compared with Cr coatings, and the best were Ni-13Mo and Ni-14W. The layer’s micrographs present homogeneous layers with nodules distributed in the surface and cracks can be observed to Ni-17Mo and Ni-25Mo. Ni-Mo and Ni-W coatings are crystalline exhibiting a face-centred-cubic structure in the solid solution. The microhardness increased with the Mo or W percentage and heat treatments increased the hardness of the coatings, while Cr decreased its hardness with heat treatment. / O comportamento da corrosão e as propriedades mecânicas de revestimentos de Ni-Mo e Ni-W em soluções de NaCl foram investigados neste trabalho, sendo feito um estudo comparativo com as propriedades do revestimento de cromo industrial. Todas as camadas foram obtidas sob controle galvanostático em temperatura ambiente e foram avaliadas em termos de composição química, microestrutura, icrodureza, cristalinidade e resistência à corrosão. A morfologia superficial foi caracterizada por microscopia de varredura eletrônica (MEV), a composição química foi determinada por energia dispersiva de raios X (EDX), a microdureza foi medida pelo teste de dureza de Vickers e a estrutura cristalina foi determinada por difração de raios X (DRX). Os testes eletroquímicos de corrosão foram realizados por polarização potenciodinâmica linear (PP) e pela espectroscopia de impedância eletroquímica (EIE). Os resultados mostraram que os revestimentos de Ni-Mo e Ni-W apresentam boa resistência à corrosão quando comparados com os revestimentos de Cr, sendo os melhores Ni-13Mo e Ni-14W. As camadas foram homogêneas, com nódulos distribuídos na superfície e a presença de trincas para as camadas Ni-17Mo e Ni-25Mo. Os revestimentos apresentam uma estrutura cristalina do tipo cúbica de face centrada com a formação de uma solução sólida. A microdureza aumentou com o percentual de Mo e W na camada e com o tratamento térmico a dureza das ligas aumentaram, enquanto as camadas de Cr diminuíram sua dureza com o tratamento térmico.

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