Abderrahim Famiri

Searching for material symmetries in the burr wood of Thuja by a direct contact ultrasonic method on spherical samples

This work is part of a program that aims at studying the burr wood of thuja (Tetraclinis articulata). The goal of this work is to identify material symmetries of burr wood to improve its machining. To have a sufficient number of data and to limit the variability between samples, an ultrasonic experimental device, in direct contact on spherical samples, has been developed and improved. Until now, the geometry used in direct contact ultrasonic methods was either cubic or polyhedral allowing to obtain, on the same sample, 3 (cube) to 13 (polyhedron) measurements or usable data. By choosing a reasonable angular gap, the spherical geometry allows the ultrasonic velocity to be measured in 133 different directions on the same specimen. We present here the adaptation and development of the ultrasonic experimental device and results obtained on (i) aluminum chosen as a reference material, (ii) beech wood and (iii) burr wood of thuja.

NATURAL DURABILITY OF Cedrus atlantica WOOD RELATED TO THE BIOACTIVITY OF ITS ESSENTIAL OIL AGAINST WOOD DECAYING FUNGI

The Atlas cedar, Cedrus atlantica is a resinous species of Pinaceae originated from North Africa and well known for its noble timber. This work was conducted to assess the natural durability of its wood, to study the chemical composition of essential oil extracted from its sawdust wood and to test the bioactivity of this essential oil against four wood decaying fungi: Gloeophyllum trabeum, Oligoporus placenta, Coniophora puteana and Trametes versicolor. The assessment of natural durability of wood was conducted according to the methods described in the European standards, CEN/TS 15083-1 and NF EN 350-1. Mass losses of wood specimens, after 16 weeks of exposure to fungi attack, in laboratory test, showed that Cedrus atlantica wood is very durable to durable against wood decay fungi attack. The extraction of essential oil from sawdust by hydro-distillation yielded about 3,35% and the chemical analysis of this essential oil by GC-MS showed that E-γ-Atlantone (19,73%); E-α- Atlantone (16,86%), 5-Isocedranol (11,68%); 9-iso-Thujopsanone (4,45%); Cedranone (4,13%) and Z α- Atlantone (4,02%) were the main major identified components. The antifungal activity tested by the direct contact technique on agar medium showed a strong inhibition of wood decaying fungi, especially Gloeophyllum trabeum inhibited at 1/1000 v/v concentration.

Physico-Mechanical Behavior and Recovery of Wood-Plastic Composite (WPC) Based on Recycled High Density Polyethylene (HDPE)

In this paper, we have investigated the stability, mechanical properties, and the microstructure of wood–plastic composites, which were fabricated using recycled high-density polyethylene (HDPE) with pine wood flour used as fillers. Composite panels were obtained using hot-press molding. The tensile and flexural properties of the composites based on recycled HDPE revealed the strength properties of the composites can be improved by increasing the polymer content, also the composite formulation significantly improved the morphology and the stability. Scanning Electron Microscope (SEM) was used to characterize the morphology of the wood particulate/HDPE interface. It was clearly proved from the results that wood-plastic composite (WPC) based on recycled high density polyethylene (HDPE) can be successfully utilized to fabricate stable and strong WPCs.

Determination of growth stresses indicator, moisture profiles and basic density of clonal eucalyptus wood

Liberation of growth stresses during cutting and sawing prevents the use of eucalyptus as working timber. The occurrence of log-end cracks and planks, due to the release of growth stress pre-existing in the standing tree, causes severe damage at the early stage of wood transformation. In this study, we determine the GSI of two clonal eucalyptus wood originated from Gharb Mâamora plantations, so as to have an idea about the occurrence of cracks before first wood transformation. The measurements of growth stress indicator (GSI) were performed on six trees of each clone by the single-hole method. Changes in moisture and basic density were carried out on wood discs. Results of GSI have showed the existence of variability in the distribution of GSI within the studied trees. Clonal eucalyptus trees exhibit a high nervousness illustrated by high GSI values associated with the presence of reaction wood. Changes in moisture and basic density of wood discs for these clones are variable from the core to the periphery. The important GSI values and moisture content and basic density gradients are responsible of splitting, cracks and distortions observed after cutting and/or sawing.

Improvement of Harvesting Practices for Sustainable Development of Moroccan Rosemary Mediterranean’s Scrublands

Abstract In Morocco, rosemary stands are mainly threatened by current practices which compromise their sustainability. To improve harvesting practices within natural stands, an experimental design was followed during 4 years in Debdou forest, Eastern Region of Morocco, where rosemary covers large areas. Harvesting practices tested to operate rosemary at different seasons of the year influenced regeneration of leaf biomass and essential oils production. During spring, the clear-cut allowed the best resumption, the highest yield of essential oil (2.03 %), and a supported production in leaf biomass. In summer, harvesting operations must be avoided because of their negative effect on vegetal growth and essential oils yields. Harvesting half of the clumps during autumn has the advantage to keep the part of the plant that is going to flower soon at the end of autumn, thus allowing rosemary clumps to play, firstly, their nectar-producing to beekeeping role, and secondly, to ensure the production of seeds for natural regeneration. Finally, winter is a convenient period for the rejuvenation of rosemary shrubs. Therefore, the best rate of resumption was obtained by clear-cutting (179.4 %) which allows a better regeneration and an improvement of the production. The best essential oil yields extracted from leaves, by hydro-distillation, were obtained during spring. Results of a chemical analysis, by GC-MS, showed that chemical composition did not varied drastically during different seasons and these essential oils were characterized by high amounts of 1,8-cineol (51.6–54.9 %) followed by significant quantities of α-pinene (6.4–8.5 %), camphor (12.6–16.9 %) and borneol (5.3–8.6 %).