Centrifugal melt spinning of polyvinylpyrrolidone (PVP)/triacontene copolymer fibres

Polyvinylpyrrolidone/1-triacontene (PVP/TA) copolymer fibre webs produced by centrifugal melt spinning were studied to determine the influence of jet rotation speed on morphology and internal structure as well as their potential utility as adsorbent capture media for disperse dye effluents. Fibres were produced at 72 C with jet head rotation speeds from 7000 to 15,000 r min-1. The fibres were characterised by means of SEM, XRD and DSC. Adsorption behaviour was investigated by means of an isothermal bottle point adsorption study using a commercial disperse dye, Dianix AC-E. Through centrifugal spinning nanofibers and microfibers could be produced with individual fibres as fine as 200–300 nm and mean fibre diameters of ca. 1–2 lm. The PVP/TA fibres were mechanically brittle with characteristic brittle tensile fracture regions observed at the fibre ends. DSC and XRD analyses suggested that this brittleness was linked to the graft chain crystallisation where the PVP/TA was in the form of a radial brush copolymer. In this structure, the triacontene branches interlock and form small lateral crystals around an amorphous backbone. As an adsorbent, the PVP/TA fibres were found to adsorb 35.4 mg g-1 compared to a benchmark figure of 30.0 mg g-1 for a granular-activated carbon adsorbent under the same application conditions. PVP/TA is highly hydrophobic and adsorbs disperse dyes through the strong ‘‘hydrophobic bonding’’ interaction. Such fibrous assemblies may have applications in the targeted adsorption and separation of non-polar species from aqueous or polar environments

CELLULAR AUTOMATA MODEL – LANDSCAPE DYNAMICS SIMULATION TOOL IN THE PROCESS OF CHANGE IN LAND USE AND COVER IN THE CITY OF GAÚCHA DO NORTE – MT

Abstract. The factors that contribute to land use change in the municipality of Gaúcha do Norte - MT, are entirely linked to the economic process and agricultural production. This process has left Brazil in a state of alert due to the process of deforestation and loss of tropical forests. From 2000 to 2010, the forest areas converted into agriculture accounted for 13.3%, the main factor that directly potentiated with deforestation was the cultivation of soybeans, which in turn was occupying places previously occupied by livestock and pushing the livestock forest inside. The phenomena of land use change and land cover start from multidimensional issues in the environmental and economic context. The use of environmental modeling through cellular automata to analyze land use change phenomena and reproduce the trajectory through future land use simulations and evolution establishes an integration associated by mathematical models and flow integration systems. That predict the trajectory of land use change, thus generating a dynamic model capable of predicting future land use changes by replicating possible patterns of landscape evolution and enabling assessments of future ecological implications for the environment. </jats:p

Un'altra educazione \ue8 possibile

Il volume mette in tensione diverse concezioni dell'educazione (da diritto universale a merce) a partire da una selezione di contributi internazionali presentati al Primo Forum Mondiale dell'Educazione a Porto Alegre (Ottobre 2001)

BALANÇO DAS AVALIAÇÕES MUNICIPAIS DO PLANO DE AÇÕES ARTICULADAS: DESAFIOS ATUAIS AO DESENVOLVIMENTO DA POLÍTICA NACIONAL PAR

Resumo: Em 2012, o Plano de Ações Articuladas (PAR) deixa de limitar-se ao Plano de Metas Compromisso Todos pela Educação, ascendendo à condição de política de Estado. Apoiado na análise dos estudos teórico-empíricos que versam sobre a avaliação do PAR na esfera municipal, publicados no período 2007-2012, o presente artigo visa ao delineamento de alguns dos desafios postos ao desenvolvimento da atual política nacional PAR. Observa que a prestação de assistência técnica e financeira por parte do MEC tem sido crescente e consensualmente ajuizada como deficitária, acarretando interrupção de um elevado número de ações desencadeadas pelos municípios, com impactos mais expressivos na dimensão correspondente à formação inicial e continuada de professores (Educação Infantil e Ensino Fundamental) e demais profissionais da educação, quadro agravado por grandes debilidades locais, em especial as decorrentes dos elevados déficits de qualificação de pessoal técnico e de infraestrutura