A experiência de aprendizagem baseada em projetos interdisciplinares em um novo campus de engenharia sob a perspectiva dos discentes

This work aims to describe the experience of Project Based Learning (PBL) in the course of Mechanical Engineering (Engineering Campus - UACSA) of the Federal Rural University of Pernambuco (UFRPE), Brazil. To this end, it were considered both the perceptions of the students and also the data analysis, collected from 20 students, about the experience. The questionnaire answered by the students was organized around six topics: theme of the project, developed competences and learning skills, teamwork, role of teachers, the project assessment and project as a teaching-learning methodology. Also they wrote on the positive and less positive aspects and pointed suggestions for the implementation of PBL. Concisely, the survey results revealed that teamwork, the need for interpersonal relationships and the development of soft skills (autonomy, initiative and creativity in creating the prototype, research capacity, decision, organization, problem solving, time management) are prominent positive aspects, added to the fact that PBL brings the chance for the students to put into practice the theoretical knowledge acquired during the course. Problems for the project's implementation were identified as: lack of instruments and conditions given to students for the development of the prototype, the dense load of disciplines of the semester, the non-suitability of some disciplines involved in the project, plus the bad interaction between them. Besides the fact that there was the need for greater dialogue between the disciplines of the semester and/or a more substantial adjustment of the Pedagogical Course Project (PPC), the PBL as a teaching-learning methodology in the course of Mechanical Engineering met the main expectations, and also collaborated for integration, socialization and learning of students. Therefore it is defended its permanence and expansion (over all semesters of the course) at UACSA/ UFRPE.O presente artigo aborda a primeira experiência da Unidade Acadêmica do Cabo de Santo Agostinho campus das engenharias da UFRPE com o trabalho interdisciplinar através da metodologia de Aprendizagem Baseada em Projetos Interdisciplinares -PBL. Para tal, foi utilizado ao final do semestre letivo um questionário voltado aos discentes, com o objetivo de avaliar a experiência em suas várias dimensões. Os resultados da pesquisa presente neste artigo baseiam-se, sobretudo, nas percepções dos estudantes sobre o processo de implementação e avaliação desta experiência. O questionário respondido pelos estudantes foi organizado em torno de seis tópicos: tema do projeto, aprendizagens e competências desenvolvidas, trabalho em equipe, papel dos docentes, avaliação no projeto e projeto como metodologia de ensino-aprendizagem. Também responderam de forma dissertativa sobre os aspetos positivos e negativos e apontaram sugestões para a implementação do PBL. A investigação realizada através do questionário revela que o trabalho em equipe, o exercício do relacionamento interpessoal e o desenvolvimento de competências transversais são aspectos positivos de destaque, somados ao fato do PBL trazer possibilidade para que os discentes coloquem em prática os conhecimentos teóricos adquiridos durante o curso, promovendo o interesse dos discentes pelo próprio aprendizado ao terem contato com a aplicabilidade dos conceitos aprendidos no curso, além de desenvolver nos mesmos um senso crítico. Somando-se a isto, também foram apontadas algumas dificuldades, principalmente no que diz respeito à articulação entre as disciplinas e a carência de instrumentos para o desenvolvimento dos protótipos. No entanto, embora esses aspectos tenham sido verificados, percebe-se que o uso do PBL como metodologia de ensino cumpre o seu papel de atender aos objetivos propostos para uma aprendizagem ativa e o desenvolvimento de sujeitos críticos e reflexivos(undefined)info:eu-repo/semantics/publishedVersio

Surface modification of alumina nanoparticles with silane coupling agents

In the present paper we describe the surface modification of alumina nanoparticles using epoxy-containing alkoxysilanes (silane coupling agents, SCA). The materials were characterized using infrared spectroscopy and solid-state nuclear magnetic resonance. Whereas, neat alumina nanoparticles could be expectedly modified with the afore mentioned SCA, as evidenced by 13C CPMAS NMR, the presence of arylsulphonates at the surface of alumina caused the ring-opening polymerization of the epoxide. This polymerization reaction facilitated the surface modification of alumina by the SCA. X-ray powder diffraction and 27Al MAS NMR clearly demonstrated that in spite of the SCA polymerization, there were neither structural changes nor phase transitions in the alumina after the surface modification. The surface modification decreased the thermal stability of alumina, in comparison to pristine alumina nanoparticles

Electrical conductive behavior of polymer composites prepared with aqueous graphene dispersions

Graphene was produced from graphite powder using the three best known water-based conversion approaches. The first two are based on chemical oxidation methods, only differing in the reduction process, either by the use of hydrazine or by thermal expansion, respectively. The third one is based on long-term ultrasonic exfoliation. Water/surfactant solutions were prepared with these three nanofillers and latex technology concept was applied for the preparation of conductive graphene/polystyrene composites with well-dispersed graphene platelets. The samples were characterized with respect to filler properties and morphology, and their influences on electrical conductive properties of the composites were compared. Microscopic studies showed that both reduction processes lead to agglomeration/wrinkling of the platelets, even though they yield composites with high conductivity and low percolation threshold. Although mechanical ultrasound exfoliation of graphite produces less defective multi-layer graphene, these platelets have a smaller lateral size and their composites exhibit a higher percolation threshold. Differences in electronic transport behavior were observed, which suggest direct contact transport competing with tunneling

Tip-enhanced Raman spectroscopy and mapping of graphene sheets

Single graphene sheets, a few graphene layers, and bulk graphite, obtained via both micromechanical cleavage of highly oriented pyrolytic graphite and carbon vapor deposition methods, were deposited on a thin glass substrate without the use of any chemical treatment. Micro-Raman spectroscopy, tip-enhanced Raman spectroscopy (TERS), and tip-enhanced Raman spectroscopy mapping (TERM) were used for characterization of the graphene layers. In particular, TERM allows for the investigation of individual graphene sheets with high Raman signal enhancement factors and allows for imaging of local defects with nanometer resolution. Enhancement up to 560% of the graphene Raman band intensity was obtained using TERS. TERM (with resolution better than 100 nm) showed an increase in the number of structural defects (D band) on the edges of both graphene and graphite regions

Surface modification of alumina nanoparticles with silane coupling agents

In the present paper we describe the surface modification of alumina nanoparticles using epoxy-containing alkoxysilanes (silane coupling agents, SCA). The materials were characterized using infrared spectroscopy and solid-state nuclear magnetic resonance. Whereas, neat alumina nanoparticles could be expectedly modified with the afore mentioned SCA, as evidenced by 13C CPMAS NMR, the presence of arylsulphonates at the surface of alumina caused the ringopening polymerization of the epoxide. This polymerization reaction facilitated the surface modification of alumina by the SCA. X-ray powder diffraction and 27Al MAS NMR clearly demonstrated that in spite of the SCA polymerization, there were neither structural changes nor phase transitions in the alumina after the surface modification. The surface modification decreased the thermal stability of alumina, in comparison to pristine alumina nanoparticles. © 2010 Sociedade Brasileira de Química

Production and characterization of graphene-based nanocomposites of different natures and their applications in aqueous quinoline adsorption: A comparative study

Quinoline (QN) is a basic nitrogenous compound normally present in the wastewater from petroleum industry, being a toxic and harmful contaminant of emerging concern. In contrast, separation methods for QN capture are essential from an economic point of view, since quinoline has a wide range of industrial applications. This work aims to study and compare the application of two graphene oxide (GO) nanocomposites - graphene oxide/agar hydrogel (GO/agar) and magnetic graphene oxide (Mag.GO) – as adsorbents for aqueous quinoline. For Mag.GO, Freundlich isotherm model was best fitted to the equilibrium data, for GO/agar all isotherm models fitted the experimental data. The maximum experimental adsorption capacities in the equilibrium were approximately 25 mg g−1 for GO/agar, and 53 mg g−1 for Mag.GO. The increase in the acetate buffer concentration did not seem to significantly affect the adsorption capacities in both composites, which might indicate the selective adsorption of QN. Adsorption-desorption tests were performed for both nanocomposites with HCl and NaOH, and quinoline was efficiently recovered with NaOH in each case, even after three adsorption-desorption cycles. Although phytotoxicity assays with quinoline solution still indicated toxic effects before and after adsorption, both adsorbents proved to be good for quinoline removal, with Mag.GO showing greater adsorption capacity