Resumo: Esta proposta baseou-se no modelo estrutural para análise da avaliação formativa, composto por processos inter-relacionados: comunicação de expectativas e critérios de sucesso; obtenção, coleta e interpretação de informações; fornecimento de feedback; e regulação da aprendizagem. Para ajudar o professor na implementação da avaliação formativa, articularam-se, com esses processos, as práticas: metodologia de aprendizagem baseada em problemas (ABP) e dimensões culturais de Hofstede. Durante um semestre e meio avaliou-se estatisticamente o desempenho de 55 estudantes. Competências e habilidades foram avaliadas em situações-problemas retiradas do Exame Nacional do Ensino Médio. O perfil cultural foi determinado pelo questionário Value Survey Model 1994. Como resultado observou-se melhora no desempenho acadêmico (p<0,05) e no comportamental dos estudantes (p<0,05). Porém, como a atribuição de nota é exigência do sistema, a postura avaliativa percorreu um nível intermediário entre classificatória e formativa. Formulários de apoio incluídos no plano pedagógico da escola favoreceram a prática de avaliação formativa.

Abstract: This proposal was based on a structural model for analyzing formative assessment that is composed of interrelated processes: communication of expectancies and success criteria, elicitation, collection and interpretation of information, provision of feedback, and regulation of learning. To help the teacher in the implementation of formative assessment, specific practices were articulated with those processes, namely the problem-based learning (PBL) methodology and Hofstede's cultural dimensions. For one semester and a half, the performance of 55 students was statistically evaluated. Competences and abilities were assessed in problem situations taken from Exame Nacional do Ensino Médio, and the cultural profile was determined by the Value Survey Model 1994 questionnaire. As a result, there was an improvement in both students' academic performance (p<0.05) and behavioral performance (p<0.05). However, as rating is a requirement in the system, the evaluation was at an intermediate degree between classificatory and formative. Supportive feedback forms included in the school’s pedagogical plan favored the practice of formative assessment.

O presente trabalho visa a investigar o efeito da deformação plástica severa introduzida pelo processo de embutimentos sucessivos, seguidos de forjamento rotativo, trefilação e do subseqüente recozimento a 950°C por 1 hora na microtextura de um compósito nanoestruturado de Nb-30%Cu em volume. A caracterização microestrutural foi realizada com o auxílio das técnicas de microscopia ótica (MO), microscopia eletrônica de varredura (MEV) e difração de elétrons retroespalhados (EBSD). Após o recozimento, a matriz de cobre exibia uma microestrutura totalmente recristalizada com uma textura do tipo fibra-gama. Os filamentos de Nb, após o processamento termomecânico empregado, exibiram uma fraca textura do tipo fibra-alfa. Os resultados mostraram que ocorreu um processo de recristalização parcial em várias áreas dos filamentos de Nb, em virtude de uma competição microestrutural.

The effect of severe plastic deformation introduced by the bundling-and-drawing process and the subsequent annealing in vacuum at 950°C for 1 hour on the microtexture of Nb-30%Cu (in vol%) nanostructured composite has been investigated. The microstructural characterization was carried out using light optical microscopy (LOM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). The microstructure of the Cu matrix was completely recrystallized, displaying a gamma-fiber texture after annealing. A weak alpha-fiber texture arises in the Nb filaments after the employed thermomechanical process. Results showed that in several areas of the multifilamentary niobium, a partial recrystallization developed, indicating microstructural competition.

The optimization of the energy generated by a MagnetoHydroDynamic (MHD) channel using a superconducting magnet demands the optimization of the magnetic field of the system and of the critical points on the magnet winding. This work must include the development of a high performance superconductor wire suitable for this system. Aiming to the construction of improved performance MHD channel, it was developed a low cost superconductor wire, with the required characteristics. The wire was made using a technology compatible with the assembling steps and heat treatment conditions of the MHD superconducting magnets fabrication. It was used the internal Sn method in Nb-7.5wt%Ta tube to fabricate a 271-filament wire with a diameter of 0.81 mm and a Cu/nonCu ratio of 2.3. The wire was heat treated at 200 °C to diffuse the Sn into the Cu shell, producing bronze, followed by the final reaction at temperatures ranging from 670 °C to 730 °C during 25 to 150 h, to produce (Nb,Ta)3Sn. The superconducting wire characterization was made measuring the critical current Ic versus the applied magnetic field in the range of 5 to 20 T, the critical temperature Tc and the residual resistivity ratio (RRR). The wire transported critical currents above those available in commercial superconducting wires. These values of Ic are higher than the expected values for the optimization of the MHD channel.