Percorrer por autor "Fiúza, A."
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- Assessment of the environmental radiation by in situ gamma ray spectrometryPublication . Dinis, M. L.; Góis, Joaquim; Carvalho, José Soeiro de; Meira Castro, Ana C.; Fiúza, A.Naturally occurring radioactive materials (NORM) under certain conditions can reach hazardous radiological levels contributing to an additional exposure dose to ionizing radiation. Most environmental concerns are associated with uranium mining and milling sites, but the same concerns should be addressed to natural near surface occurrences of uranium as well as man-made sources such as technologically enhanced naturally occurring radioactive materials (TENORM) resulting from phosphates industry, ceramic industry and energy production activities, in particular from coal-fired power plants which is one of the major sources of increased exposure to man from enhanced naturally occurring materials. This work describes the methodology developed to assess the environmental radiation by in situ gamma spectrometry in the vicinity of a Portuguese coal fired power plant. The current investigation is part of a research project that is undergoing in the vicinity of Sines Coal-Fired Power Plant (south of Portugal) until the end of 2013.
- A case study on the eco-efficiency performance of a composite processing industry: evaluation and quantification of potential improvementsPublication . Ribeiro, M.C.S.; Meira Castro, Ana C.; Silva, F.J.G.; Meixedo, JP; Oliveira, L.; Alvim, M.R.; Fiúza, A.; Dinis, M.L.In this study, an attempt was made in order to measure and evaluate the eco-efficiency performance of a pultruded composite processing company. For this purpose the recommendations of World Business Council for Sustainable Development (WCSD) and the directives of ISO 14301 standard were followed and applied. The main general indicators of eco-efficiency, as well as the specific indicators, were defined and determined. With basis on indicators’ figures, the value profile, the environmental profile, and the pertinent eco-efficiency ratios were established and analyzed. In order to evaluate potential improvements on company eco-performance, new indicators values and eco-efficiency ratios were estimated taking into account the implementation of new proceedings and procedures, at both upstream and downstream of the production process, namely: i) Adoption of a new heating system for pultrusion die-tool in the manufacturing process, more effective and with minor heat losses; ii) Recycling approach, with partial waste reuse of scrap material derived from manufacturing, cutting and assembly processes of GFRP profiles. These features lead to significant improvements on the sequent assessed eco-efficiency ratios of the present case study, yielding to a more sustainable product and manufacturing process of pultruded GFRP profiles.
- Design of experiments applied to the mix design process of polymer mortar materials modified with GFRP recyclatesPublication . Ribeiro, M.C.S.; Fiúza, A.; Dinis, M.L.; Meira Castro, Ana C.; Silva, F.J.G.; Meixedo, JPIn this work, the effect of incorporation of recycled glass fibre reinforced plastics (GFRP) waste materials, obtained by means of shredding and milling processes, on mechanical behavior of polyester polymer mortar (PM) materials was assessed. For this purpose, different contents of GFRP recyclates (between 4% up to 12% in mass), were incorporated into polyester PM materials as sand aggregates and filler replacements. The effect of silane coupling agent addition to resin binder was also evaluated. Applied waste material was proceeding from the shredding of the leftovers resultant from the cutting and assembly processes of GFRP pultrusion profiles. Currently, these leftovers, jointly with unfinished products and scrap resulting from pultrusion manufacturing process, are landfilled, with supplementary added costs. Thus, besides the evident environmental benefits, a viable and feasible solution for these wastes would also conduct to significant economic advantages. Design of experiments and data treatment were accomplish by means of full factorial design approach and analysis of variance ANOVA. Experimental results were promising toward the recyclability of GFRP waste materials as aggregates and reinforcement for PM materials, with significant improvements on mechanical properties with regard to non-modified formulations.
- Experiments on new polymer based mortars filled with FRP waste recyclates - a quantitative analysisPublication . Ribeiro, M.C.S.; Meixedo, JP; Meira Castro, Ana C.; Fiúza, A.; Dinis, M.L.; Silva, F.J.G.Glass fibre-reinforced plastics (GFRP) have been considered inherently difficult to recycle due to both: cross-linked nature of thermoset resins, which cannot be remolded, and complex composition of the composite itself. Presently, most of the GFRP waste is landfilled leading to negative environmental impacts and supplementary added costs. With an increasing awareness of environmental matters and the subsequent desire to save resources, recycling would convert an expensive waste disposal into a profitable reusable material. In this study, efforts were made in order to recycle grinded GFRP waste, proceeding from pultrusion production scrap, into new and sustainable composite materials. For this purpose, GFRP waste recyclates, were incorporated into polyester based mortars as fine aggregate and filler replacements at different load contents and particle size distributions. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified polymer mortars. Results revealed that GFRP waste filled polymer mortars present improved flexural and compressive behaviour over unmodified polyester based mortars, thus indicating the feasibility of the waste reuse in polymer mortars and concrete. © 2011, Advanced Engineering Solutions.
- Fate Hazardous elements in soils surrounding a coal-fired power plant complexPublication . Dinis, Maria L.; Góis, Joaquim; Fiúza, A.; Carvalho, J.S.; Meira Castro, Ana C.A study was carried out in the vicinity of a Portuguese coal-fired power plant in order to determine the extent and degree of soils contamination that may be related to the dispersion of the atmospheric emissions from the this coal-fired power plant. Metals and soluble ions concentrations have been determined both in-situ and in soil samples collected at sites potentially affected by the stacks’ emissions. The analysis of trace elements was performed by means of X-ray fluorescence. The concentrations of twenty trace elements were determined: As, Ba, Ca, Co, Cu, Fe, Hg, K, Mn, Mo, Ni, Pb, Rb, S, Sb, Se, Sr, Ti, Zn, Zr, even though very few measurements were obtained for some of these elements in some specific areas around the power plant. The spatial distribution obtained by kriging in combination with the analysis of the data by Principal Component Analysis (PCA) showed three important situations in what concerns to metal concentration in soils and according to soil uses and geographic localization: the power plant (peak concentrations in the immediate area around the stacks), in the prevailing wind direction (from N-NW to E-SE and SE-S) and the area comprised between 6 and 20 km from the power plant (mostly agricultural and pasture areas). Considering that soil’s concentration for the studied elements may had its origin in the past atmospheric emissions from the coal-fired power plant and were accumulated in surface soils over the past decades, the height of the stacks and the dispersion by seasonal winds, could explain the observed enrichment of some elements in the area between the 6 and 20 km. However, some of the typical heavy metals associated with coal combustion emissions such as Cd, Cr, Hg and Ni were not significantly registered in the area under study and this may suggest the contribution from other industrial plants present in the region.
- Hybrid thermoset polymeric composites – an Innovation towards sustainabilityPublication . Meira Castro, Ana C.; Ribeiro, M. C. S.; Meixedo, João Paulo; Silva, F.J.G.; Fiúza, A.; Dinis, M.L.; Alvim, M.In this study, a new waste management solution for thermoset glass fibre reinforced polymer (GFRP) based products was assessed. Mechanical recycling approach, with reduction of GFRP waste to powdered and fibrous materials was applied, and the prospective added-value of obtained recyclates was experimentally investigated as raw material for polyester based mortars. Different GFRP waste admixed mortar formulations were analyzed varying the content, between 4% up to 12% in weight, of GFRP powder and fibre mix waste. The effect of incorporation of a silane coupling agent was also assessed. Design of experiments and data treatment was accomplished through implementation of full factorial design and analysis of variance ANOVA. Added value of potential recycling solution was assessed by means of flexural and compressive loading capacity of GFRP waste admixed mortars with regard to unmodified polymer mortars. The key findings of this study showed a viable technological option for improving the quality of polyester based mortars and highlight a potential cost-effective waste management solution for thermoset composite materials in the production of sustainable concrete-polymer based products.
- Metodologia de dimensionamento de colunas de arrastamento por ar utilizadas para remoção de compostos orgânicos voláteis em aquíferos contaminadosPublication . Meira Castro, Ana C.; Fiúza, A.No presente trabalho faz-se uma apresentação do processo de arrastamento por ar em colunas com enchimento desordenado, utilizadas na remoção de compostos orgânicos voláteis (COV) de aquíferos contaminados. Apresentam-se os fundamentos teóricos relativos ao comportamento hidrodinâmico da coluna e ao processo de transferência de massa de contaminante da água para o ar. Posteriormente, são apresentados os modelos mais frequentemente utilizados na previsão da perda de carga da fase gasosa ao longo da coluna e da altura de enchimento necessária a garantir uma eficiente remoção de COV da água subterrânea.
- Optimising the energy consumption on pultrusion processPublication . Silva, Francisco J. G.; Ferreira, F.; Ribeiro, M. C. S.; Meira Castro, Ana C.; Castro, M.R.A.; Dinis, M.L.; Fiúza, A.This study is based on a previous experimental work in which embedded cylindrical heaters were applied to a pultrusion machine die, and resultant energetic performance compared with that achieved with the former heating system based on planar resistances. The previous work allowed to conclude that the use of embedded resistances enhances significantly the energetic performance of pultrusion process, leading to 57% decrease of energy consumption. However, the aforementioned study was developed with basis on an existing pultrusion die, which only allowed a single relative position for the heaters. In the present work, new relative positions for the heaters were investigated in order to optimise heat distribution process and energy consumption. Finite Elements Analysis was applied as an efficient tool to identify the best relative position of the heaters into the die, taking into account the usual parameters involved in the process and the control system already tested in the previous study. The analysis was firstly developed based on eight cylindrical heaters located in four different location plans. In a second phase, in order to refine the results, a new approach was adopted using sixteen heaters with the same total power. Final results allow to conclude that the correct positioning of the heaters can contribute to about 10% of energy consumption reduction, decreasing the production costs and leading to a better eco-efficiency of pultrusion process.
- Recycling of pultrusion production waste into innovative concrete-polymer composite solutionsPublication . Ribeiro, Maria Cristina Santos; Fiúza, A.; Meira Castro, Ana C.; Silva, F.J.G.; Meixedo, JP; Dinis, M.L.; Costa, C.; Ferreira, F.; Alvim, M.R.In this study, the added value resultant from the incorporation of pultrusion production waste into polymer based concretes was assessed. For this purpose, different types of thermoset composite scrap material, proceeding from GFRP pultrusion manufacturing process, were mechanical shredded and milled into a fibrous-powdered material. Resultant GFRP recyclates, with two different size gradings, were added to polyester based mortars as fine aggregate and filler replacements, at various load contents between 4% up to 12% in weight of total mass. Flexural and compressive loading capacities were evaluated and found better than those of unmodified polymer mortars. Obtained results highlight the high potential of recycled GFRP pultrusion waste materials as efficient and sustainable admixtures for concrete and mortar-polymer composites, constituting an emergent waste management solution.
- Remediação sustentável de reservas de água subterrânea contaminada: breve apontamentoPublication . Meira Castro, Ana C.; Fiúza, A.No presente trabalho faz-se uma breve introdução à problemática da contaminação de águas subterrâneas para consumo humano. Apresenta-se, também, uma caracterização dos diferentes tipos de fontes de contaminação e tipos de contaminantes associados. Por fim, são apresentadas algumas ferramentas tecnológicas existentes, bem como os respectivos campos de aplicação, com vista à descontaminação de sítios contaminados.