Besma Bouslimi, Yves Bergeron, Ahmed Koubaa. Regional, Site, and Tree Variations ofWood Density and Growth in Thuja occidentalis L. in the Quebec Forest. 2022. Forests 13(12):1984
Thuja occidentalis L. wood is desirabl, e for wooden structures that require wood density uniformity. Wood density is a wood quality indicator related to numerous morphological, mechanical, physiological, and ecological properties. This study aimed to investigate the regional, site, and tree-to-tree variations of T. occidentalis wood density and growth components through the analysis of X-ray densitometer data. A total of 287 trees were randomly sampled from 11 sites in the Abitibi-Témiscamingue regions in Québec, Canada. The average ring density at breast height was 356 kg m−3, with a small difference between earlywood and latewood (167 kg m−3), indicating a relatively uniform wood. Ring density and width varied significantly between the Abitibi and the Témiscamingue regions, mainly in the juvenile wood. Trees from the Abitibi region showed higher ring density than those in the Témiscamingue region. In contrast, the ring width was higher in the Témiscamingue region. Site, tree, and cambial age significantly (p < 0.001) affected wood density and growth components. However, the largest variation is due to the tree-to-tree variation, accounting for about 15%–31% of the total variation. Compared to ring widths, ring density components showed a considerably smaller tree-to-tree variation and higher variation (7.1%) with cambial age than ring widths (0.6%). Ring width correlated positively and significantly (p < 0.001) with average temperature and annual precipitation, while ring density correlated negatively and significantly (p < 0.001) with average temperature and annual precipitation.
Yves Bergeron, Besma Bouslimi, Ahmed Koubaa. Intra-Ring Variations and Interrelationships for
SelectedWood Anatomical and Physical Properties
of Thuja Occidentalis L.. 2019. Forests 10(4):339
DOI : 10.3390/f10040339
Intra-ring variation in wood density and tracheid anatomical properties and wood property interrelationships were investigated in Thuja occidentalis L. Samples were taken from three stands in Abitibi–Témiscamingue, Quebec, Canada. The structure of T. occidentalis wood is simple, homogeneous and uniform, which is desirable for wooden structures that require wood uniformity. From early- to latewood, cell and lumen diameter decreased, while cell wall thickness increased. These changes led to an increase of the cell wall proportion. Wood ring density and width interrelationships were weaker in mature wood compared to juvenile wood. Earlywood density is the more important in determining mature wood density than latewood density and proportion. Earlywood density explains 92% and 89% of the variation in juvenile and mature wood density, respectively. The negative relationship between ring density and width, although significant, was low and tends to weaken with increasing tree age, thus providing the opportunity for silvicultural practices to improve both growth and wood density. Ring width was positively and strongly correlated to early- and latewood width, but negatively correlated to tracheid length and latewood proportion. Accordingly, increases in ring width produce smaller tracheids and wider earlywood without a corresponding increase in latewood. Practical implications of the results are discussed.
Flavia Braghiroli, Nesrine Hamza, Hassine Bouafif, C.M. Neculita, Ahmed Koubaa. Production, characterization, and potential of activated biochar as adsorbent for phenolic compounds from leachates in a lumber industry site. 2018. Environnemental Research 25(26):26562-26575
DOI : 10.1007/s11356-018-2712-9
There is growing interest in low-cost, efficient materials for the removal of organic contaminants in municipal and industrial effluents. In this study, the efficiency of biochar and activated biochar, as promising adsorbents for phenol removal, was investigated at high (up to 1500 mg L?1) and low concentrations (0.54 mg L?1) in synthetic and real effluents (from wood-residue deposits in Québec), respectively. The performance of both materials was then evaluated in batch adsorption experiments, which were conducted using a low solid/liquid ratio (0.1 g:100 mL) at different phenol concentrations (C0?=?5–1500 mg L?1), and at 20 °C. Activated biochars presented higher phenol adsorption capacity compared to biochars due to their improved textural properties, higher micropore volume, and proportion of oxygenated carbonyl groups connected to their surface. The sorption equilibrium was reached within less than 4 h for all of materials, while the Langmuir model best described their sorption process. The maximum sorption capacity of activated biochars for phenol was found to be twofold relative to biochars (303 vs. 159 mg g?1). Results also showed that activated biochars were more effective than biochars in removing low phenol concentrations in real effluents. In addition, 95% of phenol removal was attained within 96 h (although 85% was removed after 4 h), thus reaching below the maximum authorized concentration allowed by Québec’s discharge criteria (0.05 mg L?1). These results show that activated biochars made from wood residues are promising potential adsorbent materials for the efficient treatment of phenol in synthetic and real effluents.
Sahbi Ouertani, Soufien Azzouz, R. Bahar, Lamine Hassini, Ali Belghith, Ahmed Koubaa. Microwave drying kinetics of jack pine wood: determination of phytosanitary efficacy, energy consumption, and mechanical properties. 2018. European Journal of Wood and Wood Products 76(4):1101-1111
DOI : 10.1007/s00107-018-1316-x
The aims of this study were to determine (1) the effects of microwave irradiation on the drying kinetics of jack pine wood, (2) the phytosanitary efficacy, and (3) the processing energy consumption and mechanical strength of the dried product. Microwave drying experiments were performed at 2.45 GHz frequency and at microwave powers ranging from 300 to 1000 W. Results indicate that higher microwave power and initial wood temperature and lower sample thickness increases the internal sample temperature, improves the drying rate, and reduces both drying time and energy consumption. The microwave irradiation efficacy to sanitize jack pine wood boards was determined in terms of temperature/time combinations based on actual drying kinetics according to standards for phytosanitary measures. The energy required to dry 12 mm thick wood board samples at microwave power ranging from 300 to 1000 W was in the range of 36.4–12.3 MJ/kg of water, respectively, for up to 65% energy consumption savings. The impact of microwave power on the mechanical properties was not statistically significant, although mechanical properties tended to decrease with increasing power. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
Mourad Saddem, Hassine Bouafif, Sébastien Migneault, Bernard Riedl, Ahmed Koubaa. Effect of fiber and polymer variability on the rheological properties of wood polymer composites during processing. 2018. Polymers Composites 40(S1):E609-E616
DOI : 10.1002/pc.24909
We investigated the effects of fiber variability, size and content on the fusion characteristics of wood particle-reinforced high-density polyethylene (HDPE). Five types of wood sawdust were used: eastern white cedar, with sapwood, and heartwood treated separately; jack pine divided into wood and bark; and black spruce. Three different fiber length classes were also used. Composite pellets containing wood particles at 25, 35, and 45% by weight with HDPE were made using a co-rotating twin-screw extruder. The pellets were melted and mixed during 7 min in a torque rheometer at 180°C. We also investigated the polymer variation using HDPE, polypropylen (PP), polyvinyl chloride (PVC), and a blend of (80% HDPE+ 20% PP) where wood fiber proportion and length were kept constant. We varied the mixing temperature to reach the melting temperature range of each polymer. Mixing and melting times, maximum torque and stabilized torque were obtained. Adding wood fibers to the HDPE increased processing time and torque energy. At constant fiber length and proportion, torque properties varied with fiber origin. Higher fiber length and proportion increased torque energy and time of stabilization. Thus, using wood fibers with different properties will lead to significant variations in processing, such as in extrusion or injection. The fusion characteristics of wood polymer composite vary among polymers. The PVC showed the highest steady-state torque. The formulation containing a polymer blend of HDPE and PP showed the highest torque energy. This higher torque energy is explained by the interaction of the incompatible polymeric chains of the two thermoplastic polymers. © 2018 Society of Plastics Engineers.
Manel Haddar, Ahmed Elloumi, Cheldy Bradai, Foued Elhalouani, Sébastien Migneault, Ahmed Koubaa. Synergetic effect of Posidonia oceanica fibres and deinking paper sludge on the thermo-mechanical properties of high density polyethylene composites. 2018. Industrial Crops and Products 121:26-35
DOI : 10.1016/j.indcrop.2018.04.075
This study evaluated the reinforcement potential of Posidonia oceanica fibres (POF) and deinking paper sludge (DPS) on the thermo-mechanical properties of high density polyethylene (HDPE) binary and hybrid composites. The weight ratios of the fillers (POF and/or DPS) to the polymer were 0:100; 20:80; 30:70 and 40:60 (wt:wt). Maleated polyethylene (MAPE) was added at a proportion of 3% by weight. The chemical composition, structural and thermal properties and morphology of the fillers were investigated by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The mechanical (tensile and impact strength) and thermal properties (TGA and Differential Scanning Calorimetry (DSC)) of the binary and hybrid composites were also investigated. Binary and hybrid composite properties depend on the chemical composition of the fillers (POF and DPS), the filler/matrix interfacial adhesion and the POF: DPS ratio. The tensile modulus and strength of the binary and hybrid composites increased with increasing filler content (POF or/and DPS). A better interfacial adhesion between fillers and matrix was achieved in the presence of MAPE. HDPE/POF/MAPE composites achieved the highest tensile modulus and strength with 40% POF. But lower thermal stability, ductility and impact strength were found with the addition of the POF. However, the thermal stability, crystallinity, ductility and toughness improved in HDPE/POF/DPS/MAPE hybrid composites due to the addition of DPS or the substitution of POF by DPS. © 2018 Elsevier B.V.
François Godard, Pierre Rivard, Joël Soucy, Ahmed Koubaa. Rheological behavior of high-density polyethylene (HDPE) filled with paper mill sludge. 2018. Journal of Applied Polymer 135:46484
DOI : 10.1002/app.46484
A comparative study was conducted of composites made with sludge from three different paper mills. Sludges were obtained from a thermomechanical pulp (TMP), a chemico?TMP (CTMP), and a Kraft mill with a feedstock of primarily black spruce. The primary sludge (PS) and secondary sludge (SS) were mixed at two different ratios (PS:SS?=?7:3 and 9:1) and blended with high?density polyethylene (HDPE) at 20%, 30%, and 40% proportion. The blends were tested using plate–plate geometry before subjection to frequency sweep by oscillation rheometry. The storage modulus (G?), loss modulus (G?), and complex viscosity (?*) increased with increasing paper sludge content. Decreasing the PS:SS ratio from 9:1 to 7:3 decreased G?, G?, and ?*. Differential scanning calorimetry showed that sludge addition increased both the melting and crystallization temperature, for a positive effect on crystallinity. Although the behavior of sludge–high?density polyethylene blends differed from that of traditional wood plastic composite made with wood flour, they obtained G?, G?, and ?* values of the same magnitude. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46484.
Azmul Huda, Pierre Périnet, Yves Fortin, Roger E. Hernandez, Ahmed Koubaa, Alain Cloutier. Phenotypic and genotypic correlations for wood properties of hybrid poplar clones of Southern Quebec. 2018. Forests 9(3):140
DOI : 10.3390/f9030140
This study aims to understand the phenotypic and genotypic correlations among wood anatomical, physical, and mechanical properties of hybrid poplar clones. Samples were taken from seven clones grown on three sites in Southern Quebec, Canada. Five trees per clone were randomly sampled from each site to measure anatomical (fiber length, fiber proportion, vessel proportion, fiber wall thickness, tension wood), physical (basic density, volumetric, longitudinal, tangential, and radial shrinkage), and mechanical wood properties (flexural modulus of elasticity (MOE), modulus of rupture (MOR), ultimate crushing strength parallel to the grain). The observed phenotypic and genotypic correlations between these wood properties were moderate to strong, except for fiber length and vessel proportion. Genotypic correlations for all wood properties were higher than for corresponding phenotypic correlations. Furthermore, fiber length showed weak correlations, whereas, vessel proportion showed strongly negative correlations with all other properties. Strong correlations were also found among fiber proportion, fiber wall thickness, basic density, and mechanical properties. Furthermore, results from this study show close genotypic and phenotypic correlations between fiber proportion, fiber wall thickness, and wood density, which consequently affect the mechanical performance of wood products. These findings indicate that there is a substantial opportunity to improve wood quality by selecting several wood properties for different end uses. © 2018 by the authors.
Dexiang Wu, Wei-dan Ding, CuiCui Luo, Abdelkader Chaala, Ahmed Koubaa. Robust DEA to assess the reliability of methyl methacrylate-hardened hybrid poplar wood. 2017. Annals of Operation Research 248 (1-2):515-529
DOI : 10.1007/s1047
We transformed a data envelopment analysis (DEA) optimization model into a robust second-order cone equivalent to immunize against output perturbation in an uncertainty set. The robust DEA framework was then used to assess the effect of a wood hardening treatment using methyl methacrylate (MMA) on selected hybrid poplar clones. Because the performance of MMA-hardened hybrid poplar clones varies across clones, ranking hardened clones is crucial for developing hardening treatments for specific industrial applications. The numerical results demonstrate that the hardening treatment can be optimized by applying the proposed DEA framework to select the best hybrid poplar clone types and the optimal amount of impregnated chemicals.
Claudia B. Caceres, Roger E. Hernandez, Ahmed Koubaa. Effects of log position in the stem and commercial thinning on jack pine chip dimensions produced by a chipper-canter. 2017. European Journal of Wood and Wood Products 75(3): 359-373
DOI : 10.1007/s00107-016-1062-x
Fifteen stems of jack pine (Pinus banksiana Lamb.) coming from three commercial thinned (CT) plots (control, moderate, and intensive thinning) in the Abitibi-Témiscamingue region, Canada, were cross-cut into three 2.4 m length sections: bottom, middle, and top logs. Logs were processed with a chipper-canter at three cutting widths (CW 12.7, 19.1, and 25.4 mm), producing chips and a three faced cant. Chips were assessed by thickness, width, and length. Knot characteristics [total knot number (TKN) and area (TKA)] were assessed in the three cant faces. Growth ring attributes [earlywood density, latewood density (LWD), ring density (RD), earlywood proportion (EWP), ring width, and rings per mm], mechanical properties (shear, splitting, modulus of elasticity and modulus of rupture in bending), and basic density were evaluated on samples obtained within each CW area. The weighted mean chip thickness (WCT) was significantly affected by the log position in the stem (LPS) and CW. WCT increased as CW increased. Jack pine produce thicker chips than black spruce, when processed under the same cutting parameters. Thickness of chips coming from bottom and middle logs was similar due to a greater taper of the bottom log, which slightly increased this dimension. Thickest chips were produced in the top log due to a higher TKA and TKN towards the top of the stem. Multiple linear regressions showed that TKA, CW, and RD were significant predictors of WCT. Chip size distributions were significantly affected by the CT, LPS, and CW. Thinned stands logs appeared to produce smaller chips than natural stand logs. Moreover, chip thickness distribution was affected primarily by TKA and EWP, while the width and length distribution was mainly affected by EWP, LWD, and TKN. Chip size in jack pine is to some degree determined by knot attributes, growth ring characteristics, and wood density of the raw material. These results suggest the potential advantage of sorting logs prior to chipping, either by species, LPS and/or provenance (thinned or natural stands).
voir la liste complète
Youssef Ben Slim, Ahmed Koubaa, Sana Koubba, Yves Bergeron, Alexis Achim. Prédiction des propriétés physiques et chimiques du bois d’érable à sucre par la spectroscopie infrarouge proche 24e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2022-11-22)
Achraf Ammar, Ahmed Koubaa, Yves Bergeron, Dorra Gassara, Pierre Grondin. Potentiel de la tomographie acoustique pour la caractérisation non destructive de la proportion de la carie et son impact sur le module d’élasticité du bois de l’érable à sucres 23e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue (2021-12-07)
Ana Verhulst-Casanova, Fabio Gennaretti, Ahmed Koubaa, Yves Bergeron, Alexis Achim, Steve Bédard. Liens entre le climat et l'anatomie du bois d'érable à sucre (Acer saccharum Marshall) à la limite nordique de son aire de répartition au Québec 23e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue (2021-12-07)
Ahmed Koubaa, Hassine Bouafif. Utilisation du biochar activé comme support de croissance des micro-organismes capables de dégrader les hydrocarbures aromatiques polycycliques (HAPs) 22e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, complètement virtuel (2020-12-02)
Fayez Elleuch, Ahmed Koubaa, Mohamed Khlif. Amélioration de la stabilité dimensionnelle et de la durabilité des composites bois-polymères à haute teneur en fibres 21e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2019-11-30)
Mayssa Hmaied, Ahmed Koubaa, Hassine Bouafif. Effets des prétraitements de la biomasse forestière résiduelle des conifères sur la productivité et la qualité des huiles essentielles 21e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2019-11-30)
Feker Mnif, Ahmed Koubaa, Hatem Mrad. Détection des contaminants métalliques avant l’étape de pressage des panneaux à lamelles orientées par voie électromagnétique. 21e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2019-11-30)
Raymond Pendi, Annie DesRochers, Ahmed Koubaa. Effets de l'espacement initial des plants de peuplier hybride sur les propriétés physiques du bois, suivant un gradient latitudinal dans l'ouest du Québec 21e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2019-11-30)
Yasmine Zribi, Ahmed Koubaa, Cheldy Bradai. Effets de l'éclaircie commerciale et de la fertilisation sur le module d’élasticité dynamique du bois de l’épinette noire à l’échelle du cerne 21e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2019-11-30)
He Wang, Ahmed Koubaa, Sébastien Migneault, François Godard. Affiche 17
La morphologie et l’adhésion de l’aluminium et le Composite bois-polymère (CBP) 20e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Lorrainville, Québec. (2018-11-30)
Flavia Braghiroli, Ahmed Koubaa. L’utilisation des résidus de bois pour la production de matériaux hautement poreux pour les applications dans l'environnement et stockage d'énergie 20e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Lorrainville, Québec. (2018-11-30)
Thana Saffar, Hassine Bouafif, Armand Langlois, Ahmed Koubaa. Affiche 9
Utilisation de la lignine pyrolytique dans la fabrication des mousses de polyuréthane rigide 19e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Ste-Germaine-Boulé, Québec. (2017-11-30)
Abdelmajid Ben Jmeaa, Sébastien Migneault, Ahmed Koubaa. Affiche 1
Moulage par injection de polymères renforcés en fibres de cellulose avec haute charge en cellulose 19e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Ste-Germaine-Boulé, Québec. (2017-11-30)
Fatma Rzem, Ahmed Koubaa, Alain Leduc. Outils non destructifs pour l’étude des propriétés du bois de l’épinette noire 19e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Ste-Germaine-Boulé, Québec. (2017-11-30)
Nesrine Hamza, Ahmed Koubaa, Hassine Bouafif. Activation de biochars à partir de résidus de bois lignocellulosiques 19e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Ste-Germaine-Boulé, Québec. (2017-11-30)
Fedi Boukhris, Ahmed Koubaa, Sébastien Migneault. Défibrage des granules énergétiques et des composites bois-polymères 19e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Ste-Germaine-Boulé, Québec. (2017-11-30)
Mayssa Hmaied, Hassine Bouafif, Sara Magdouli, Ahmed Koubaa. Affiche 6
Étude de l’impact du conditionnement et du prétraitement de la biomasse forestière résiduelle sur les produits de transformation : cas des huiles essentielles 19e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Ste-Germaine-Boulé, Québec. (2017-11-30)
Ramzi Ayadi, Ahmed Koubaa. Potentiel des fibres torréfiées pour la fabrication de composites bois-polymère 18e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2016-12-01)
Besma Bouslimi, Ahmed Koubaa, Hassine Bouafif. Caractérisation des propriétés chimiques en utilisant la technologie d’infrarouge : cas du pin gris (Pinus banksiana Lamb) 18e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2016-12-01)
Besma Bouslimi, Ahmed Koubaa, Yves Bergeron. Effet de l’âge cambial et de la hauteur de l’arbre sur la variation intracerne de la densité du bois : cas du cèdre de l’est (Thuja occidentalis L.) 18e colloque de la Chaire AFD. Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Québec. (2016-12-01)
