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Influência do volume vesical na diminuição da dose recebida na bexiga e no PTV ...

Introdução: O cancro retal continua a ser um dos principais problemas de saúde a nível mundial, sendo a toxicidade gastro-intestinal e génito-urinária os efeitos tardios da radioterapia mais reportados. A utilização da Belly-Board para minimizar essa toxicidade, reduzindo o volume de bexiga e intestino delgado irradiados é recomendada. No entanto, o protocolo mais adequado para o volume vesical nestes doentes é...

Use of acoustic energy in sand casting of aluminium alloys

During the last years, some researchers have focused the development of ultrasonic microstructure refinement /modification techniques of die-casting aluminium alloys, to improve their properties. The developed techniques are highly efficient when applied to the die-casting process, but their capability with sand and ceramic moulding are unknown. Sand/ceramic aluminium castings are prone to coarse microstructure...

Factors affecting the metal recovery yield during induction melting of aluminiu...

Machining operations of cast parts usually generate considerable amounts of waste in the form of chips (usually 3–5% of the casting weight). Traditionally, swarf is sold to scrapers and remelters, but this option is quite expensive because the selling price is roughly 30% of the acquisition price of the commercial 2nd melt raw material. For most aluminium foundries that incorporate machining operations in their...

Aluminium evaporation during ceramic crucible induction melting of titanium alu...

Melting TiAl based alloys in ceramic crucibles often leads to chemical contamination, alloy heterogeneity and non-metallic inclusions. The severity of such phenomena usually depends on the nature of crucible materials, the melting stock composition and the melting parameters, namely superheating time and temperature and melting pressure. Among the referred drawbacks, Al loss during melting is a critical aspect,...

Evaluation of functionally graded ceramic crucible for induction melting of TiA...

During the last years a very significant effort to develop a melting crucible for induction melting of Ti based alloys at competitive cost has been carried out by many researchers, where the authors are included. Results obtained so far have shown that no material accomplishes the melting crucibles two main demands: inertness facing titanium alloys and suitable/enough thermal-shock resistance. Until now, yttriu...

Influence of indirect ultrasonic vibration on the microstructure and mechanical...

The influence of high intensity ultrasound (US) propagating through a steel mold on the microstructure and mechanical properties of die-cast AlSi9Cu3, for different levels of electric power and at different distances to the waveguide/mold interface. The influence of those parameters on the morphology of -Al and eutectic Si and on the volume of porosity were investigated and characterized. The morphological ch...

Use of acoustic energy in the processing of molten aluminium alloys

During the last years aluminium alloys have been gaining increased acceptance as structural materials in the automotive and aeronautical industries, mainly due to their light weight, good formability and corrosion resistance. However, improvement of mechanical properties is a constant in research activities, either by the development of new alloys or by microstructure manipulation. This presentation focuses a ...

The influence of melt treatment process on the quality and permormance [i. é pe...

The performance of a mechanical component is often limited by the intrinsic characteristics of the materials used or by weaknesses/limitations inherent to the manufacturing process. Despite their widespread use, the casting of aluminum alloys is not easy since they are prone to coarse and heterogeneous structures, usually dendritic. Moreover they are susceptible to hydrogen absorption during melting, requiring ...

Simulation of the nucleation of the precipitate Al3Sc in an aluminum scandium a...

Low density, high strength to corrosion and specific strength to weight ratio are properties that made aluminum alloys excellent materials for transportation industry. A promising way to develop ultra-high strength aluminum alloys is achieved by the addition of metallic elements with low solubility in aluminum, promoting the Al3X (X = Sc) nanoparticles formation. Moreover, Al alloys have applications in the aer...

Survival of a probiotic culture incorporated into orange juice after spray-drying