A importância do lúdico no processo de aprendizagem

Relatório de estágio apresentado à Escola Superior de Educação de Paula Frassinnetti para obtenção do grau de Mestre em Educação Pré-Escolar e Ensino do 1º Ciclo do Ensino BásicoEste relatório, para além de evidenciar, o papel que o lúdico tem na vida das crianças, descreve a intervenção pedagógica realizada ao longo do estágio profissionalizante. A prática pedagógica baseou-se numa reflexão constante sobre a prática, melhorando os aspetos menos positivos e indo ao encontro das necessidades e motivações das crianças. Além disso, conhecer os grupos e as suas especificidades, bem como, as respetivas instituições permitiram à estagiária adaptar a sua intervenção. O desenvolvimento da intervenção pedagógica teve etapas fundamentais, sendo estas: a observação, a planificação, a ação e a avaliação. Partindo da observação e da intervenção desenvolvida em ambos os contextos, considerou-se importante explorar de forma mais aprofundada o impacto do lúdico no desenvolvimento das aprendizagens. Através do lúdico as crianças aproximam-se ao máximo da realidade, exprimem os seus sentimentos, angústias, receios, desejos e fantasias, fazendo com que se aproximem do mundo real

Orthogonal experimental design of titanium dioxide - Poly(methyl methacrylate) electrospun nanocomposite membranes for photocatalytic applications

An orthogonal experimental method was designed to assess the influence of the electrospinning processing parameters on average diameter and distribution of poly(methyl methacrylate) (PMMA) fibers. Based on the orthogonal experimental design analysis, electrospun TiO2-PMMA nanocomposites were processed with the optimal polymer processing conditions to obtain thin fibers with a high overall surface area. Further it was found that the average fiber diameter decreases from 2.0 ± 0.5 down to 1.2 ± 0.2 μm with increasing photocatalyst content. Moreover, the wettability of samples was independent of the filler amount, and showed strong hydrophobic behavior. Thermogravimetric analysis showed that for polymer solutions with concentrations higher than 10 wt%, there was a loss of the photocatalytic particles during processing, being more evident for the sample with 40 wt% particles present in the solution, with a loss of 8 wt% of ceramic particles. The immobilization of the TiO2 nanoparticles in the polymer fibers led to an increase of the thermal stability. The photocatalytic performance was assessed by using methylene blue (MB). The nanocomposite electrospun fiber membranes had a remarkable photocatalytic activity, especially the one with higher amount of TiO2, with all the MB dye being removed from the solution after 100 min, under UV. The orthogonal experimental design is an efficient way to save time and materials in the production of photocatalytic membranes

Ultra-stretchable MWCNT-Ecoflex piezoresistive sensors for human motion detection applications

Ultra-stretchable sensors are highly desirable for wearable electronic applications. In this paper, we manufactured self-standing piezoresistive sensors using a simple method based on blending multiwall carbon nanotubes (MWCNTs) with a stretchable elastomeric matrix (Ecoflex). The sensors showed a low electrical percolation threshold of 0.3 wt%, with an elastic modulus as soft as the human skin in the forearm and palm dermis. An increase in the cross-linking degree of the matrix from 17.43 ± 0.20 mol/m 3 up to 28.55 ± 2.07 mol/m 3 was observed with the incorporation of MWCNTs, revealing that the conductive filler is covalently bonded to the elastomeric matrix. The piezoresistive sensors showed high stretchability with an outstanding linearity between the resistance change with the applied strain, up to 200%, with significant sensitivity which is essential to use these sensors in human motion applications, e.g. finger bending, walking or speaking, and even detecting a hot liquid poured into a cup. Finally, MWCNT-Ecoflex sensors showed remarkable mechanical and electromechanical response features which are essential for wearable applications to monitor human motion with minimal discomfort

Effect of the mechanical stretching on the ferroelectric properties of a (VDF/TrFE) (75/25) copolymer film

The transition phase behaviour of a vinylidene fluoride–trifluoroethylene (VDF–TrFE) copolymer film was studied after being subjected to different mechanical stretching levels in both longitudinal (L) and transversal (T) directions relatively to the initial extrusion direction. Both ferroelectric–paraelectric (FE–PE) and melting transitions were detected in the films by differential scanning calorimetry, that were not affected by L stretching. This suggests that sliding mechanism along the c-axis of such films during plastic deformation influences slightly the all-trans chain conformations and the CF2 dipole orientation. On the other hand, the FE–PE peak decreases in area and temperature upon T stretching, indicating a damage of the ferroelectric phase. However, the melting peak maintains unchanged. This fact provides evidence that the mechanical stretching do not change the total degree of crystallinity. The results suggest that the stretching induces a FE–PE phase transformation, without affecting the degree of crystallinity.Fundação para a Ciência e Tecnologia (FCT) - Programa Operacional "Ciência, Tecnologia, Inovação" (POCTI) - POCTI/CTM/33501/99.Hamburger Synchrotronstrahlungslabor (HASYLAB) - Project II-01-006 EC

Behaviour of the ferroelectric phase transition of P(VDF/TrFE) (75/25) with increasing deformation

Samples of P(VDF-TrFE) 75/25 with several permanent deformations along the two main directions of the material were investigated by means infrared spectroscopy and calorimetric methods. The evolution of the phase transition temperature and the ferroelectric anomaly with increasing deformation was monitored and correlated with the structural changes occurring in the material.Fundaçãoo para a Ciência e Tecnologia (FCT) - Programa Operacional "Ciência, Tecnologia, Inovação" (POCTI) - POCTI/CTM/33501/99

Competência emocional e prática desportiva: estudo exploratório nas escolas Dragon Force

Esta investigação pretende analisar as dimensões da inteligência/competênciaemocional nos atletas das escolas Dragon Force. Assim, o objetivo principal destainvestigação é perceber como variam as dimensões da competência emocional tendoem conta a idade, a autoavaliação enquanto estudante, a experiência na seleção do seuescalão, a prática de outras modalidades e o número de treinos semanais.A amostra é constituída por 90 participantes, com média de idade de 14,17(DP= 1,12), sendo todos os participantes alunos das escolas Dragon Force, praticantesde futebol, hóquei e basquetebol. Os instrumentos utilizados foram a versãoportuguesa do Questionário de Competência Emocional (Lima Santos & Faria, 2005),que avalia três dimensões, Perceção Emocional, Expressão Emocional e Capacidadepara Lidar com a Emoção, e tem um total de 45 itens, avaliados numa escala de Likertde 6 pontos, entre 1 e 6, e o Questionário Sociodemográfico, que foi construído deraiz para este estudo.Os resultados obtidos indicaram que não existem diferenças significativas nacompetência emocional tendo em conta a experiência na seleção do seu escalão e aprática de outras modalidades. As correlações calculadas entre as dimensões dacompetência emocional e a idade, a autoavaliação enquanto estudante, e o número detreinos semanais também não se revelaram significativas.Foram analisados e discutidos os resultados e avançadas limitações do estudoe pistas para estudos futuros no contexto desportivo

Processing and charcterization of a novel nonporous Poly(vinylidene fluoride) films in the beta-phase

Poly(vinylidene fluoride) (PVDF) has remarkable properties leading to electro-optics, electro-mechanical and biomedical applications. In particular its piezo- and pyroelectric properties provide possibilities for many technological applications. The semicrystalline nature of PVDF, combined with the occurrence of at least four crystalline phases implies a complicated physical microstructure. The most frequently described and important phase is the β. The piezo and pyro-electric properties mainly depend on this phase, so increasing the β phase content has always been a great concern. It is possible to obtain films in the β phase by solution but this material presents a high porosity leading to an opaque appearance and a decrease of the mechanical an electrical properties. In this work, porous films in the β phase were obtained directly from the solution at 600C. After applying pressure perpendicular to the surface of the film at elevated temperature, the pores in the original sample are eliminated. The changes on the morphology and crystallinity associated to the pressure applied to the samples were also studied.Fundação para a Ciência e a Tecnologia (FCT) - grants POCTI/CTM/33501/99, POCI/CTM/59425/2004, SFRH/BD/16543/2004.CNPq, FAPESP - program ALFA-PLASTINET

A novel electrospun, hydrophobic, and elastomeric styrene-butadiene-styrene membrane for membrane distillation applications

© 2017 In this study, a novel hydrophobic, microporous membrane was fabricated from styrene-butadiene-styrene (SBS) polymer using electrospinning and evaluated for membrane distillation applications. Compared to a commercially available polytetrafluoroethylene (PTFE) membrane, the SBS membrane had larger membrane pore size and fiber diameter and comparable membrane porosity. The fabricated SBS showed slightly lower water flux than the PTFE membrane because it was two times thicker. However, the SBS membrane had better salt rejection and most importantly could be fabricated via a simple process. The SBS membrane was also more hydrophobic than the reference PTFE membrane. In particular, as temperature of the reference water liquid increased to 60 °C, the SBS membrane remained hydrophobic with a contact angle of 100° whereas the PTFE became hydrophilic with a contact angle of less than 90°. The hydrophobic membrane surface prevented the intrusion of liquid into the membrane pores, thus improving the salt rejection of the SBS membrane. In addition, the SBS membrane had superior mechanical strength over the PTFE membrane. Using the SBS membrane, stable water flux was achieved throughout an extended MD operation period of 120 h to produce excellent quality distillate (over 99.7% salt rejection) from seawater

Tailoring porous structure of ferroelectric poly(vinylidene fluoride-trifluoroethylene) by controlling solvent/polymer ratio and solvent evaporation rate

Ferroelectric macroporous poly(vinylidene fluoride-trifluoroethylene) membranes have been produced by isothermal crystallization from the solution at different temperatures starting from different diluted solutions of the co-polymer in dimethylformamide. In this way pore architecture, consisting in interconnected spherical pores can be obtained. The mechanism and kinetics of solvent evaporation was investigated and related to the evolution of the polymer microstructure. The mechanism underlying the pattern formation has been discussed on the light of the Flory-Huggins (FH) lattice theory, grain boundary effects and the Cahn-Hilliard equation for mass conservation systems. It was also observed that the temperature or initial concentration of the crystallization process does not affect the phase, ferroelectric transition temperature or the melting temperature of the polymer.The authors thank the Portuguese Foundation for Science and Technology (FCT) Grants PTDC/CTM-NAN/112574/2009, PTDC/CTM/73030/2006, PTDC/CTM/69316/2006 and NANO/NMed-SD/0156/2007. V.F., C.M.C. and V.S. thank the FCT for the SFRH/BD/44289/2008, SFRH/BD/68499/2010, SFRH/BPD/63148/2009 grants, respectively. JLGR acknowledge the funding from the Programa de Apoyo a la Investigacion y Desarrollo (PAID-00-09) of the Universidad Politecnica de Valencia for a short stay in Universidade do Minho, Braga, the support of the Spanish Ministry of Science through project No. MAT2010-21611-C03-01 (including the FEDER financial support) and funding for research in the field of Regenerative Medicine through the collaboration agreement from the Conselleria de Sanidad (Generalitat Valenciana), and the Institute de Salud Carlos III (Ministry of Science and Innovation). The authors wish also thank the CeNTI - Centre for Nanotechnology and Smart Materials, Rua Fernando Mesquita, 2782, 4760-034 Vila Nova de Famalicao, Portugal for allowing the use of some experimental equipment.California, A.; Cardoso, VF.; Costa, CM.; Sencadas, V.; Botelho, G.; Gómez Ribelles, JL.; Lanceros-Mendez, S. (2011). Tailoring porous structure of ferroelectric poly(vinylidene fluoride-trifluoroethylene) by controlling solvent/polymer ratio and solvent evaporation rate. EUROPEAN POLYMER JOURNAL. 47(12):2442-2450. https://doi.org/10.1016/j.eurpolymj.2011.10.005S24422450471

Influência das condições de processamento na morfologia e fases cristalinas do PVDF e nas transições de fase do copolímero P(VDF-TrFE)

Dissertação mestrado Processamento e Caracterização de MateriaisDentro dos polímeros o poli (fluoreto de vinilideno), PVDF e os copolímeros de (fluoreto de vinilideno) (VDF) com trifluoretileno (TrFE) e misturas a partir destes materiais reúnem as propriedades piezo, piro e ferroeléctricas mais interessantes do ponto de vista científico e tecnológico. Assim sendo, o objectivo deste trabalho é optimizar as condições de processamento das diferentes fases cristalinas do PVDF. Será estudado de forma sistemática a quantidade e qualidade da fase β presente no material, por esta fase oferecer melhores propriedades electroactivas. Foram empregues dois métodos para a obter β-PVDF. Primeiro, amostras de fase a foram obtidas directamente da fusão. Depois foi estudada a transformação de fase α→β por estiramento uniaxial de amostras originalmente na fase α obtidas por fusão. As amostras de fase α foram deformadas a diferentes temperaturas e a diferentes razões de estiramento. As condições óptimas de processamento foram encontradas e o material foi caracterizado por Espectroscopia no Infravermelho por Transformadas de Fourier e Calorimetria Diferencial de Varrimento. Foi obtido por estiramento um máximo de 80% de fase β e um grau de cristalinidade de 40%, a uma razão de estiramento de 5 à temperatura de 80ºC. O recurso à Microscopia Electrónica de Varrimento permitiu o estudo da evolução da microestrutura dos polímeros durante o processo de estiramento em estudo. Outro método utilizado para obter β - PVDF é o recurso às amostras obtidas directamente da solução. Estas demonstraram possuir um grau de cristalinidade superior ao das amostras obtidas por estiramento (~50,3%) sendo constituídas exclusivamente por fase β. Contudo, amostras obtidas por este método possuem uma elevada porosidade, que enfraquece a resposta mecânica e eléctrica do material. O problema foi resolvido e a porosidade foi eliminada. O processo utilizado para eliminar a porosidade não afecta a quantidade nem a qualidade da fase β presente no polímero e também foi encontrado um ligeiro acréscimo no grau de cristalinidade do material. Amostras de fase y foram processadas e caracterizadas, tal como misturas de PVDF/P(VDF¬TrFE). Neste último caso, a transição de fase ferroeléctrica - paraeléctrica observada nestas amostras é fortemente influenciada pelas condições de processamento.Among polymers, polyvinylidene fluoride (PVDF) and the co-polymers of (vinylidene fluoride) (VDF) with trifluorethylene (TrFE) and their blends present the most interesting piezo-, pyro, and ferroelectric properties, both from a scientific and a technological standpoint. With this perspective, the aim of this work was to encounter the optimum processing conditions for the different crystalline phases of PVDF. In particular, to perform a systematic study of the quantity and quality of the β phase present in the material, as this phase offers the best electroactive properties, among the different polymer phases. Two methods were employed to obtain β -PVDF. Firstly samples in the α phase were obtained directly from the melt. Then, the α to β transformation through uniaxial stretching of α phase samples, obtained by fusion, was studied. The phase samples were mechanically deformed at different temperatures and stretch ratios. The optimum stretching conditions were found and the material characterized by Fourier Transformed Infrared Spectroscopy and Differential Scanning Calorimetry. By this method a maximum transformation of up to 80% β phase and a degree of crystallinity of 40% was obtained, at a stretch ratio of 5 and temperature of 80ºC. Scanning Electron Microscopy permitted the evolution of the microstructure of the polymers during the stretching process to be studied. The other method used in to obtain β-PVDF involved the samples in this phase being obtained directly from the solution. These samples showed a degree of crystallinity higher that the ones obtained by stretching (~50.3%) and they consisted exclusively of the β phase. However, samples obtained by this method exhibited a high degree of porosity, which decreased the mechanical and electrical responses of the polymer. The problem was overcome and the porosity was eliminated. The process used for the elimination of the porosity did not affect the amount and quality of β phase present in the polymer and also was found to provide a slight increased the degree of crystallinity. In addition samples in the y phase were also processed and characterized, as well as blends of PVDF with PVDF-TrFE. In the later case, the ferroelectric-paraelectric phase transition observed in these samples is strongly dependent on the processing conditions