Browsing by Author "Alves, L."
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- Additive manufacturing tooling for the automotive industryPublication . Leal, Rui; Barreiros, F. M.; Alves, L.; Romeiro, F.; Vasco, J. C.; Santos, M.; Marto, C.Automotive industry faces new challenges every day, new design trends and technological deployments from research push companies to develop new models and facelifts in short term, requiring new tools or tool reshaping. Concerning the current world economic scenario, decreasing time for tooling up becomes as important as decreasing time-to-market. Such scenario opens up the horizons for new manufacturing approaches like additive manufacturing, in this case, applied for tooling up a stamping process on the automotive industry for the production of body panels. This approach enables the manufacturing of stamping inserts using similar high performance alloy steel as in conventional tooling, therefore, without losing tool mechanical properties. The stamping tools produced were tested by an automotive company in order to determine tool behaviour under real operating conditions, considering the high level demands of the stamping process. The results obtained enabled to conclude that metal additive manufacturing provided tools for the stamping process with excellent performance with a significant decrease on time-to-tooling.
- Characterization and application of glycanases secreted by Aspergillus terreus CCMI 498 and Trichoderma viride CCMI 84 for enzymatic deinking of mixed office wastepaperPublication . Marques, Susana; Pala, Helena; Alves, L.; Amaral-Collaço, M. T.; Gama, Francisco Miguel; Gírio, Francisco M.Two enzymatic extracts obtained from xylan-grown Aspergillus terreus CCMI 498 and cellulose-grown Trichoderma viride CCMI 84 were characterised for different glycanase activities. Both strains produce extracellular endoxylanase and endoglucanase enzymes. The enzymes optimal activity was found in the temperature range of 45 /60 8C. Endoglucanase systems show identical activity profiles towards temperature, regardless of the strain and inducing substrate. Conversely, the endoxylanases produced by both strains showed maximal activity at different pH values (from 4.5 to 5.5), being the more acidic xylanase produced by T. viride grown on cellulose. The endoglucanase activities have an optimum pH at 4.5 /5.0. The endoxylanase and endoglucanase activities exhibited high stability at 50 8C and pH 5.0. Mannanase, b-xylosidase, and amylase activities were also found, being the first two activities only present for T. viride extract. These two enzymatic extracts were used for mixed office wastepaper (MOW) deinking. When the enzymatic extract from T. viride was used, a further increase of 24% in ink removal was obtained by comparison with the control. Both enzymes contributed to the improvement of the paper strength properties and the obtained results clearly indicate that the effective use of enzymes for deinking can also contribute to the pulp and paper properties improvement.