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Anjos O.M.S.,Escola Superior Agraria de Castelo Branco | Santos A.J.A.,Researcher Institute Investigacao Cientifica Tropical | Simoes R.M.S.,University of Beira Interior
Appita Journal

This paper reports on the relationship between the fibre morphology of six Acacia melanoxylon bleached kraft pulps, produced from wood chips with basic densities of 449, 489, 493, 505, 514 and 616 kg/m 3, and their papermaking potential. Six wood samples were selected in order to provide pulps with markedly different fibre morphological properties. The pulps were beaten in a PFI mill at 500, 2500 and 4500 revolutions under a refining intensity of 1.7 N/mm and their papermaking potential evaluated. The mean values of fibre length, fibre width and coarseness ranged between 0.78 and 0.99 mm, 17.8 and 19.4 urn, and 4.8 and 6.2 mg/100 m, respectively. As expected, the fibres characteristics have very high impact on handsheet structure, including smoothness, and on mechanical and optical properties, for the unbeaten pulps. At a given beating input (same PFI revolutions), the differences between pulps remain very high. Moreover, for a given paper density, tensile and tear strength, and light scattering coefficient are very sensitive to mean pulp fibre characteristics. Source

Barata A.M.,Instituto Nacional Of Recursos Biologicos Inrb | Rocha F.A.,Instituto Nacional Of Recursos Biologicos Inrb | Lopes V.M.,Instituto Nacional Of Recursos Biologicos Inrb | Maia J.,Polytechnic Institute of Coimbra | And 9 more authors.
Acta Horticulturae

Genetic Resources are crucial to support human wellbeing by contributing to increase the income of the rural populations, thus, their general welfare, by maintaining the traditional sustainable agricultural systems. However, their importance goes far beyond the immediate economic value, as it has also drawn considerable interest at scientific and political levels as important elements contributing to local and global food security and quality. Being a repository of unforeseen potentialities, Medicinal, Aromatic and Culinary Plants Genetic Resources (MACP-GR) should be studied and preserved for the benefit of present and future generations. In the past few decades, research programmes on MACP-GR have been focusing on biochemical evaluation of wild material. Moreover, in the last decade, efforts have been made to preserve this genetic material in situ and ex situ. Since 2000, several researchers have pulled synergies and joined efforts and have proposed collaborative networks on MACP-GR. It was possible to define a first MAP Programme for the in situ and ex situ conservation, ethnobotany, characterization, evaluation in support of the promotion of their sustainable utilisation. In Portugal, the MAP collection preserved in ex situ conditions (field, seed and in vitro collections), totals 1224 accessions belonging, inter alia, to the families Liliaceae (3%), Apiaceae (2%) and Lamiaceae (0.7%). So far, 27 species belonging to these families were characterized, evaluated and multiplied, and a total of 1394 ethnobotanical questionnaires were elaborated at national level based on 804 interviews. Through these established networks it was possible to increase the extent and effectiveness of the knowledge about this important pool of genetic material and engage in systematic morphological characterisation and biochemical evaluation. The acquired integrated and complementary knowledge will allow for and the support of MAP future actions, associating the understanding and management of biodiversity and genetic resources conservation and utilisation. Source

Anjos O.,Escola Superior Agraria de Castelo Branco | Anjos O.,University of Lisbon | Pereira H.,University of Lisbon | Rosa M.E.,University of Lisbon
European Journal of Wood and Wood Products

The behaviour of cork under three point bending stress in the radial direction was evaluated in relation to porosity (range 2.0-15.4%) and density (range 0.160-0.220 g∈cm -3). The study was made using water-boiled cork planks of two commercial quality classes (good and poor quality) collected at an industrial mill. Cork samples were cut with the largest dimension in two directions, axial and tangential, and with the load zone in the inner part and the outer part of the plank. The stress-strain curves obtained in bending were similar for the different test specimens and similar to those observed for tensile tests in cork but the mechanical resistance of cork in bending was higher than in tension and lower than in compression. The direction of the internal stress in samples submitted to bending was a highly significant factor of variation. The curves showed an initial linear elastic region with a mean Young's modulus of 14 MPa for the tangential direction and 21 MPa for the axial direction, followed by a region of a gradual cork yielding up to a peak load, and failure at an average stress of 1.2 MPa and a strain of 14%. There was significant difference in the bending properties of cork samples obtained from cork planks of different quality classes. Density and porosity were not individually well correlated with the mechanical parameters. It was however possible to model Young's modulus by combining porosity and density. © 2011 Springer-Verlag. Source

Carneiro J.,Escola Superior Agraria de Castelo Branco | Cardenas L.M.,North Wyke Research | Hatch D.J.,North Wyke Research | Trindade H.,University of Tras os Montes e Alto Douro | And 3 more authors.
Environmental Chemistry Letters

Nitrous oxide (N2O) affects climate change as a greenhouse gas and indirectly contributes to stratospheric ozone depletion. The main source of N2O in soils is denitrification which requires high soil moisture, carbon and nitrate. Nitrification inhibitors can be used to mitigate emissions of N2O from soils. In Portugal, fertilisers are often applied when soils are still relatively warm and moist conditions conducive to denitrification. A Portuguese arable soil was inhibited with dicyandiamide, a nitrification inhibitor and the effect on soil microbiological activity and composition was determined after 46 days. Soils were then incubated and received carbon and ammonium under high soil water conditions and mineral N and N2O fluxes were measured during 22 days. We found that dicyandiamide decreased microbial populations and activity, but did not alter composition. Pre-conditioning of the soil with dicyandiamide was 80% more effective in reducing fluxes of N2O than simultaneous application with fertiliser. © 2009 Springer-Verlag. Source

Anjos O.,Escola Superior Agraria de Castelo Branco | Anjos O.,University of Lisbon | Pereira H.,University of Lisbon | Rosa M.E.,University of Lisbon
Materials and Design

The behaviour of cork under tensile stress in the tangential direction was studied using cork planks of two commercial quality classes and samples taken at three radial positions in the cork planks. The stress-strain curves showed a linear elastic region approximately until 2% strain (stress at 0.4 MPa), followed by a region of decreasing slope up to the fracture at an average stress of 0.6 MPa (strain of 5%). The radial position in the cork plank was a highly significant factor of variation in the tensile properties. The tensile properties showed statistically significant correlations with cork density and porosity. Source

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