Browsing by Author "Oliveira, J."
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- Cork processing wastewater treatment/valorisation by nanofiltrationPublication . Oliveira, J.; Nunes, M.; Santos, P.; Cantinho, Paula; Minhalma, MiguelNanofiltration process for the treatment/valorisation of cork processing wastewaters was studied. A DS-5 DK 20/40 (GE Water Technologies) nanofiltration membrane/module was used, having 2.09 m(2) of surface area. Hydraulic permeability was determined with pure water and the result was 5.2 L.h(-1).m(-2).bar(-1). The membrane presents a rejection of 51% and 99% for NaCl and MgSO4 salts, respectively. Two different types of regimes were used in the wastewaters filtration process, total recycling mode and concentration mode. The first filtration regime showed that the most favourable working transmembrane pressure was 7 bar working at 25 degrees C. For the concentration mode experiments it was observed a 30% decline of the permeate fluxes when a volumetric concentration factor of 5 was reached. The permeate COD, BOD5, colour and TOC rejection values remained well above the 90% value, which allows, therefore, the concentration of organic matter (namely the tannin fraction) in the concentrate stream that can be further used by other industries. The permeate characterization showed that it cannot be directly discharged to the environment as it does not fulfil the values of the Portuguese discharge legislation. However, the permeate stream can be recycled to the process (boiling tanks) as it presents no colour and low TOC (< 60 ppm) or if wastewater discharge is envisaged we have observed that the permeate biodegradability is higher than 0.5, which renders conventional wastewater treatments feasible.
- Intelligent sensors for real-time Hazard detection and visual indication on highwaysPublication . Oliveira, J.; Soares, J.; Lourenço, A. R.; Duarte, R. P.Traffic collisions, in particular high speed car accidents often result in huge damages, long traffic queues and loss of human lives. In this work, we present an inteligente modular autonomous system that monitors traffic in highways and alerts drivers of sudden stops, in poor visual conditions. The system is composed of several identical modules, to be placed in the middle of a highway’s lane, that sense the lights and communicate their presence and velocity to their neighbour modules via RF. With such information, the nearby modules estimate the velocity of the passing cars. When the module ahead detects a car passing at a much slower speed than what was previously estimated, it alerts the other modules, so they produce a visual indication for the oncoming drivers, preventing accidents.
- Minimisation of equivalent dose to the extremities during PET radiopharmaceuticals dispensingPublication . Oliveira, J.; Hunter, J.; Carolino, Elisabete; Lucena, FilipaPositron Emission Tomography-Computed Tomography (PET/CT) has emerged as an early diagnosis and staging in several pathologies, particularly on cancer. The radiopharmaceuticals used in this technique are beta plus-emitters (β+) and radiate gamma photons (γ) with 511 keV, which is considerably higher in comparison with conventional nuclear medicine, implying that the conventional amounts of lead and tungsten in shields are not enough for an appropriate radiation protection of the practitioners. In this work, two commercially available PET radiopharmaceuticals (PET-Rph) dispensers are compared. Results demonstrate that both instruments are robust and accurate, although not precise. Also, particular care needs to be taken while working with PET-Rph, namely the arrangement of the material and equipment on the working bench.