Pausas preenchidas e domínios prosódicos: evidências para a validação do descritor fluência em um teste de proficiência oral em língua estrangeira

O presente trabalho configura um estudo sobre o emprego das pausas preenchidas eh (ɛ) e uh (ɘ) por brasileiros falantes de inglês como língua estrangeira em entrevistas do Teste de Profi ciência Oral em Língua Inglesa (TEPOLI). O estudo fundamenta-se sobre a teoria da Fonologia Prosódica de Nespor e Vogel (1986) e sobre os estudos de pausas preenchidas e o conceito de fluência de Moniz (2006), Merlo (2006) e Scarpa (1995). A investigação compõe-se de um olhar triplo: analisamos a escolha de eh e uh como sons preenchedores; investigamos os contextos prosódicos das pausas preenchidas; e examinamos a motivação cognitivo-discursiva para a inserção dessas pausas preenchidas. Os dados embasam uma reflexão sobre o conceito de fluência e oferecem maior poder descritivo à escala do teste, contribuindo, portanto, para seus estudos de validade e confiabilidade.

Properties of glass-ceramics obtained from crystallization of the SiO2-Al2O3-MgO-Li2O system with addition of ZrO2

This paper presents the study results with glass-ceramics obtained from base glass (MgO-Al2O3- SiO2-Li2O system) with addition of ZrO2 as nucleating agent. The glass was melted at 1650 degrees C for 3 h and at a heating rate of 10 degrees C/min. The molten glass was poured into a graphite mold to obtain monolithic samples and also in water in order to obtain particulate material. Such material was grinded and then pressed by both uniaxial and isostatic pressing methods before being sintered. Both the monolithic and pressed samples were performed under two different conditions of heat treatment so that their nucleation and crystallization occurred. In the first one, the samples were heated to 1100 degrees C with a heating rate of 10 degrees C/min. In the second one, there was an initial heating rate of 10 degrees C/min up to 780 degrees C, which was kept for 5 minutes. After that, the samples were heated to 1100 degrees C at a heating rate of 1 degrees C/min. Microhardness analyses showed that base glass presented values around 7.0 GPa. The glass-ceramics obtained from the powder sintering showed microhardness values lower than those obtained from monolithic samples. The highest hardness values were observed in the samples which were treated with two heating rates, whose values were around 9.2 +/- 0.5 GPa. Moreover, the glass-ceramics which were produced with an only heating rate, presented values around 7.1 +/- 0.2 GPa, very close to those observed in the base glass.