The stoichiometry of the polyanions formed by the action of nitric acid on sodium tungstate (< 0.01M) has been studied by means of electrometric techniques involving pH-potentiometric and conductometric titrations. The well defined inflections and breaks in the titration curves provide evidence for the existence of the polyanions, para-W12O41(10-) and meta-W12O39(6-) corresponding to the ratio of H+:WO4(2-) as ...
We apply a macromolecular-orientation approach to produce high molecular weight polyethylene (HMWPE) + hydroxyapatite (HA) ductile composites with the stiffness and strength within the range of human cortical bone. Our composites are produced with different amounts (10 to 50% by weight) of the reinforcement by two procedures: bi-axial rotating drum and twin screw extrusion (TSE). The processing is by convention...
A colaboração entre a indústria e a universidade é, felizmente, cada vez mais usual nos dias que correm. A criação de protocolos de investigação e desenvolvimento entre as duas partes permite a obtenção de mais valias quer para a empresa, que vê os seus problemas estudados mais detalhadamente, quer para a universidade que aprende sempre com os aspectos mais práticos do ambiente industrial. O presente trabalho,...
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