Crenças e experiências de professores no PIBID de Língua Inglesa : interação e ressignificação?

There are diverse studies about beliefs in Applied Linguistics since 1970 or so (BARCELOS, 2004), especially beliefs about teaching and learning Foreign Languages. The research about beliefs and experiences of English language teachers, who take part in a program of teaching incentive (Pibid), and, therefore, are immersed in public schools for elementary education, is relevant, once the (ac)knowledgment of these beliefs related to their teaching and learning experiences allows these teachers to reflect about the aspects that involve their teaching practice and their role as teachers of English language. The present work aims to investigate the interaction of beliefs and experiences related to foreign language teaching and learning of teachers who are participants of Pibid, in the subproject of English Language at the Federal University of Uberlândia (UFU), in 2013. The objective is to identify the beliefs and experiences about teaching and learning that the pre-service teachers (PI), the coordinator teacher (PF) and the supervisor teachers (PS) of the program show and how their beliefs and experiences influence each other and can or cannot be redefined. This is a qualitative and interpretative master’s research, in which I analized one narrative of each PI, one interview of PF and another of each PS, and, also, two meetings – the first between the PF and the PIs, and the second between all the participants in the subproject. All the data was collected at the end of their participation in Pibid, approximately one year and six months later. Therefore, I raised some beliefs and experiences about English language teaching and learning present in the teachers’ discourse and analized excerpts in their speech that evidenced the interaction with other participants and its influence to the formation, confirmation, demystification and redefinition of their beliefs. The results of this analysis bring elements that may help the constant reflection of university teachers, teachers in practice and pre-service teachers about the aspects that involve the teaching experiences in public schools.

Preparação de catalisadores para reações de esterificação do ácido oleico baseados em matrizes polímericas sulfonadas POLI(1- FENILETILENO) (PS) e POLI(1-CLOROETILENO) (PVC)

Chemical modification of polymer matrices is an alternative way to change its surface properties. The introduction of sulfonic acid groups in polymer matrices alter properties such as adhesion, wettability, biocampatibility, catalytic activity, among others. This paper describes the preparation of polymeric solid acid based on the chemical modification of poly (1-fenietileno) (PS) and Poly (1-chloroethylene) (PVC) by the introduction of sulfonic acid groups and the application of these polymers as catalysts in the esterification reaction of oleic acid with methanol. The modified materials were characterized by Infrared Spectroscopy, Elemental Analysis and titration acid-base of the acid groups. All techniques confirmed the chemical changes and the presence of sulfur associated with sulfonic acid groups or sulfates. The modified polymers excellent performance in the esterification reaction of oleic acid with methanol a degree of conversion higher than 90% for all investigated polymers (modified PS and PVC (5% w / w)), with a mass ratio of oleic acid: methanol 1:10 to 100 ° C. The best performance was observed for the modified PVC catalyst (PVCS) which showed low degree of swelling during the reactions is recovered by filtration different from that observed for polystyrene sulfonate (PSS). Given these facts, the PVCS was employed as a catalyst in the esterification reaction of oleic acid in different times and different temperatures to obtain the kinetic parameters of the reaction. Experimental data show a great fit for pseudo-homogeneous model of second order and activation energy value of 41.12 kJ mol -1, below that found in the literature for the uncatalyzed reaction, 68.65 kJ mol -1 .The PVCS exhibits good catalytic activity for 3 times of reuse, with a slight decrease in the third cycle, but with a conversion of about 78%. The results show that solid polymeric acid has good chemical stability for the application in esterification reaction of commercial importance with possible application in the biodiesel production. The advantages in use of this system are the increased reaction rate at about 150 times, at these test conditions, the replacement of sulfuric acid as a catalyst for this being the most corrosive and the possibility of reuse of the polymer for several cycles.