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Personne :
Cloutier, Alain

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Cloutier

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Alain

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Université Laval. Département des sciences du bois et de la forêt

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ncf10407795

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Voici les éléments 1 - 10 sur 70
  • PublicationRestreint
    Development of a new engineered wood product for structural applications made from trembling aspen and paper birch
    (Forest Products Research Society, 2009-07-31) Beck, Katherina; Cloutier, Alain; Salenikovich, Alexander; Beauregard L., Robert
    This study compared the bending performance of small (30 mm [1.2 in.] deep) laminated beams made from aspen oriented strand lumber (OSL), birch OSL, and commercial web-stock oriented strandboard (OSB) panels. Aspen OSL beams had an average modulus of elasticity (MOE) of 9.89 GPa (1.43 × 10^sup 6^ psi) and an average modulus of rupture (MOR) of 52.0 MPa (7.54 × 10^sup 3^ psi). The average MOE for birch OSL was 10.6 GPa (1.54 × 10^sup 6^ psi), and the average MOR was 58.4 MPa (8.47 × 10^sup 3^ psi). OSB laminated beams reached less than half of these values (5.17 GPa [0.75 × 10^sup 6^ psi] and 26.4 MPa [3.83 × 10^sup 3^ psi], respectively). Large (120 mm [4.72 in.] deep) laminated OSB beams were also tested to track the depth effect. The average MOR of aspen and birch OSL, adjusted to 120 mm depth, was estimated to be 46.7 MPa (6.77 × 10^sup 3^ psi) and 52.6 MPa (7.63 × 10^sup 3^ psi), respectively. Comparisons with laminated strand lumber products currently on the Canadian market showed the mechanical properties of this new product to be competitive
  • PublicationRestreint
    An investigation of thermochemical changes in Canadian hardwood species during wood welding
    (Springer, 2013-02-09) Erakovic, Sanja; Cloutier, Alain; Stevanovic-Janezic, Tatjana; Diouf, Papa Niokhor; Prado, Maria; Pizzi, Antonio; Royer, Mariana; Belleville, Benoît
    Thermochemical changes during wood-dowel welding were investigated in two Canadian hardwood species commonly used for indoor appearance applications: sugar maple (Acer saccharum) and yellow birch (Betula alleghaniensis). The original reference wood sample and the welded interface between two bonded wood pieces, a dowel and a substrate, were compared to explain differences in mechanical properties between species. Pyrolysis gas chromatography–mass spectrometry (Py-GC/MS), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS) were used. The gases emitted during wood welding were determined by Py-GC/MS and gas chromatography coupled with a thermal conductivity detector and a flame ionization detector (GC-TCD/FID). Results showed that thermal welding of birch and maple woods degrades hemicelluloses and affects lignin polymer through depolymerisation. Welding effectiveness is therefore directly associated with the properties of the original wood constituents, primarily lignin and carbohydrates. The lignin-related changes at the welded interface were greater for sugar maple than for yellow birch, corroborating mechanical property differences observed between the two species. The gases proportions were similar for both species and no harmful gases were detected in the smoke released during welding process.
  • PublicationRestreint
    Prediction of tracheid length and diameter in white spruce (Picea glauca)
    (Rijksherbarium/Hortus botanicus, 2015-05-20) Mvolo, Cyriac Serge; Defo, Maurice.; Cloutier, Alain; Koubaa, Ahmed; Ngueho Yemele, Martin Claude; Beaulieu, Jean
    The establishment of patterns of radial and longitudinal variations and the development of models to predict the wood anatomical properties, especially from juvenile wood, are of interest for both wood industry and researchers. Linear regressions were used to predict whole-tree, breast height and mature tracheid length and diameter in white spruce (Picea glauca (Moench) Voss) and the WBE model was used to predict the variation of tracheid diameter. Tracheid length and diameter increased from pith to bark. Tracheid length decreased, while tracheid diameter increased from apex to lower heights. Cambial age was the most important predictor of tracheid length. The final tracheid length models with either a log transformation or a third-order polynomial of cambial age explained 82% of the variation in the whole-tree tracheid length. At breast height, 83% of the variation in the whole tracheid length was explained using the juvenile value at a cambial age of 3 years. Up to 87% of the variation was explained by the model, including the average value of juvenile wood. However, mature wood tracheid length at breast height could not be predicted from juvenile wood. Distance from the apex predicted the tracheid widening in outer rings but failed to predict tracheid expansion of samples collected at fixed cambial ages. The WBE explained 86% of conduit widening in the outer rings. The sampling strategy, i.e. collecting samples longitudinally at a fixed cambial age vs. at a fixed calendar year is important in predicting tracheid diameter.
  • PublicationAccès libre
    Sensitivity study of a numerical model of heat and mass transfer involved during the medium-density fiberboard hot pressing process
    (Society of Wood Science and Technology, 2010-04-01) Deteix, Jean; Cloutier, Alain; Fortin, André; Kavazovic, Zanin.
    The objective of this work was to estimate the impact of the variability of the medium-density fiberboard mat heat and moisture transfer properties on the results predicted by a numerical model of hot pressing. The three state variables of the model, temperature, air pressure, and vapor pressure, depend on parameters describing the material properties of the mat known with a limited degree of precision. Moreover, different moisture sorption models and initial moisture contents also have an impact on the numerically predicted results. In this sensitivity study, we determined the impact of variations of the mat properties, sorption models, boundary conditions, and initial MC on the state variables. Our study shows that mat thermal conductivity, convective mass transfer coefficient of the external boundary, and gas permeability have the most significant impact on temperature, gas pressure, and MC within the mat. On the other hand, the convective heat transfer coefficient of the external boundary has no impact on the state variables. The sorption model affects significantly mat MC predictions only. The initial MC of the mat has a strong influence on the internal gas pressure.
  • PublicationAccès libre
    Radial variation of density and anatomical features of Eucalyptus nitens trees
    (Society of Wood Science and Technology, 2017-07-01) Salvo Sepúlveda, Linette Paola; Cloutier, Alain; Leandro-Zuñiga, Laura; Contreras, Helga; Elustondo, Diego; Ananías Abuter, Rubén
    This paper studies the relationship between apparent density and some anatomical properties of Eucalyptus nitens such as vessel frequency, vessel area, ring width, fiber cell wall thicknesses, and fiber length. The study involved 29 trees from 10 families of Eucalyptus nitens cut from a 17-yr-old plantation in Southern Chile. The properties were determined along the radial direction of the trees by using X-ray equipment and at selected positions through microscope and fiber quality analyzer equipment. The results showed that the anatomical properties of E. nitens did not change gradually from pith to bark, but they were better described by dividing the tree radius into three different wood-zones referred as inner-, middle-, and outer-wood. The apparent density of E. nitens was dependent of the vessel area, cell wall area, ring width, and latewood width. The correlation coefficient between apparent density and vessels area was negative and the correlation coefficient between apparent density and cell wall area, latewood ring width, and total ring width were positive. These means that E. nitens wood with lower density tended to have higher vessel area, and lower fiber cell wall area, ring width, and latewood width.
  • PublicationRestreint
    Mechanical characterization of asymmetric high density polyethylene/hemp composite sandwich panels with and without a foam core
    (Sage, 2015-07-24) Rodrigue, Denis; Kavianiboroujeni, Azam; Cloutier, Alain
    This work investigates the effects of different design parameters such as hemp content in the skins (10–40% wt.), layer thickness (1 and 2 mm), and foaming agent content in the core (0% wt., 0.6% wt. and 1.2% wt.) on the flexural properties of three layer sandwich panels of hemp and high density polyethylene produced by compression molding. The results show that hemp content was the most significant parameter for the flexural properties of these panels. In addition, it was found that specific modulus and strength (per unit weight) were 30% and 36% higher when using a foam core, respectively.
  • PublicationRestreint
    Densification of wood veneers by compression combined with heat and steam
    (Springer, 2011-02-01) Mariotti, Nicolas; Cloutier, Alain; Fang, Chang-Hua; Koubaa, Ahmed; Blanchet, Pierre
    Wood veneer 700×700 mm2 specimens made with aspen (Populus tremuloides) and hybrid poplar clone 15303 (Populus maximowiczii × Populus balsamifera) were densified using heat, steam, and pressure. Temperatures of 140, 160, 180, 200, and 220°C were applied at a maximum steam pressure of 550 kPa and maximum press hydraulic pressure ranging from 4.5 to 9.0 MPa. After densification, the oven-dry density increased significantly, veneers darkened, and lathe checks that were present on veneers before densification were conglutinated and veneer surface roughness decreased. Densified veneers showed markedly reduced hygroscopicity: the higher the densification temperature, the lower the wood hygroscopicity. The Brinell hardness of densified veneer was about two to three times that of control for both aspen and hybrid poplar. Tensile and bending strength also increased significantly after densification. However, the mechanical properties of densified veneers decreased slightly with increased densification temperature. The modulus of elasticity in tension and bending increased after densification, especially at high temperatures. A very high compression set recovery was found for veneers densified at low temperatures. Recovery decreased dramatically when densification temperature exceeded 180°C. Almost no recovery was found for veneers densified at 220°C.
  • PublicationAccès libre
    Chemical changes induced in Pinus radiata and Eucalyptus nitens following the densification process
    (Pulp and Paper Technical Association of Canada, 2015-01-31) Cloutier, Alain; Stevanovic-Janezic, Tatjana; Chavez, Romina; Koumba, Georges; Bustos, Cecilia
    Densification of wood leads to improvement of its mechanical properties. Specimens of Pinus radiata and Eucalyptus nitens wood were densified using heat, steam, and pressure to improve their mechanical properties and thus enhance their utilization. At a maximum steam pressure of 550 kPa and a maximum press hydraulic pressure ranging from 4.5 to 9 MPa, selected temperatures of 160°C, 180°C, and 200°C were used to check the mechanical properties and to identify the chemical composition of wood samples before and after densification. Densified wood samples showed markedly reduced hygroscopicity. The chemical changes in the wood constituents occurring during densification were characterized using FT-IR, Py-GC/MS, and XPS. According to the densification process between pine and eucalyptus, the results obtained showed that the densification effects were better for Eucalyptus nitens than for Pinus radiata. The FT-IR analysis revealed a high condensation index for pine lignin and the low condensation index for eucalyptus lignin, indicating easier formation of C-C linkages by densification in pine lignin. Py-GC/MS analyses were performed to follow the lignin/carbohydrate ratio, and these revealed major carbohydrate losses during densification at the highest temperature.
  • PublicationRestreint
    Genetic control of wood properties in Picea glauca - an analysis of trends with cambial age
    (National Research Council of Canada, 2010-04-15) MacKay, John; Lenz, Patrick; Cloutier, Alain; Beaulieu, Jean
    We investigated the genetic control of wood properties as a function of cambial age to enable improvement of juvenile wood attributes in white spruce (Picea glauca (Moench) Voss). Increment cores were taken from 375 trees randomly selected from 25 open-pollinated families in a provenance–progeny trial repeated on three sites. High-resolution pith-to-bark profiles were obtained for microfibril angle (MFA), modulus of elasticity (MOE), wood density, tracheid diameter and cell wall thickness, fibre coarseness, and specific fibre surface with the SilviScan technology. Heritability estimates indicated that genetic control of cell anatomy traits and wood density increased with cambial age, whereas the genetic control of MFA and MOE remained relatively low across growth rings. Wood density, radial cell diameter, cell wall thickness, and specific fibre surface were highly heritable, indicating that significant genetic gains could be expected in tree improvement programs, although cambial age at selection may strongly influence the magnitude of realized gains. In contrast, growth-related properties, such as ring width, core length, and tree height, gave weak or nonsignificant heritability estimates. Adverse correlations between mechanical strength and properties related to paper quality suggest that breeding strategies must incorporate both types of traits to improve white spruce wood quality for different end uses.
  • PublicationRestreint
    Comparison of mechanical properties of oriented strand board made from trembling aspen and paper birch
    (Springer, 2009-05-30) Beck, Katherina; Cloutier, Alain; Salenikovich, Alexander; Beauregard L., Robert
    This study compared the performance of oriented strand boards (OSB) made from trembling aspen, a low-density hardwood species, and OSB made from paper birch, a medium-density hardwood species. The birch strands were thinner than the aspen strands to ensure a comparable specific surface. Three levels of adhesive content were used: 3.5%, 5.0%, and 7.0%. Internal bond (IB) and modulus of elasticity (MOE) and modulus of rupture (MOR) for flatwise and edgewise bending were determined. Both species performed equally well in IB (3.5% adhesive content: 0.46 MPa, 5.0%: 0.60 MPa, and 7.0%: 0.65 MPa). The values of MOE in flatwise bending were slightly lower for birch than for aspen panels (11.8 GPa for aspen and 10.6 GPa for birch), and the MOR values were not significantly different (combined 68.3 MPa). Edgewise bending properties were not significantly different for the two species with a MOE of 10.5 GPa and a MOR of 43.2 MPa.