The variation of wood density and mechanical properties with site, tree and within tree (longitudinal and radial) were studied for blackwood (Acacia melanoxylon R. Br.) grown in four sites in Portugal. Twenty trees were randomly selected (40 cm dbh class, 33-51 years of age), sampled at three stem height levels (5%, 35% and 65% of tree height) and three radial positions (10%, 50% and 90% of radius). They were further tested for air-dry density at 12% moisture content, bending strength (MOR), modulus of elasticity (MOE) and compression strength parallel to grain (CS), using ISO standards. The overall mean properties of blackwood were: 654 kg m À3 density, 139 N mm À2 MOR, 141 Â 10 2 N mm À2 MOE and 61 N mm À2 CS. Site was not a significant source of variation for all wood properties. The variation between individual trees was the most important. Within the tree, the radial variation was highly significant for all traits, while the longitudinal variation was only significant for density. The correlation of density with the mechanical properties was moderate. Blackwood showed potential for being an alternative species to supply the industry with valuable hardwood timber. The significant differences found between the trees demonstrate the possibility of selection and improvement for increased wood quality.

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1This article presents a computational model and some simulation results for fibrous materials such as paper. To obtain a better understanding of the influence of fibre properties on the paper structure a novel paper model was developed. This is a physically based model where paper is formed by the sequential deposition of individual fibres. The model intends to capture key papermaking fibre properties like morphology, flexibility, and collapse and process operations such as fibre deposition, network forming or densification. This model is a step forward in transverse paper modelling. In fact, it is a three dimensional model that includes the fibre microstructure, that is, lumen and fibre wall thickness, with a resolution up to 0.05 lm. To test the model validity and predictive capability, laboratory hand sheets were used to study the network formation of an office paper, mainly produced from Eucalyptus globulus bleached Kraft pulp. This paper was characterized via an experimental design that included factors such as raw material and beating degree. The resulting porous structure was characterized and the mechanical performance was assessed. The computational simulation was used to investigate the relative influence of fibre properties such as fibre flexibility, dimensions and collapsibility. The developed multiscale model gave realistic predictions and enabled us to link fibre microstructure and paper properties.Keywords: Three dimension modelling / fibre modelling / cellulosic fibre materials modelling / fibre flexibility and collapsibility / office paper case study / Schlüsselwörter: Dreidimensionale Modellierung / Fasermodellierung / Modellierung zelluloser Fasermaterialien / Flexibilität und Kollabierneigung der Fasern / Untersuchung von Büropapier /

The fraction with molecular size >100 kDa corresponds to 56% of the organic load. Molecular size of pollutants is a major constraint to biodegradability. Ozone efficiency for improving biodegradability increases with molecular size. To raise biodegradability by ozonation the best outcome was with compounds >20 kDa.