Pour savoir comment effectuer et gérer un dépôt de document, consultez le « Guide abrégé – Dépôt de documents » sur le site Web de la Bibliothèque. Pour toute question, écrivez à corpus@ulaval.ca.
 

Personne :
Cloutier, Alain

En cours de chargement...
Photo de profil

Adresse électronique

Date de naissance

Projets de recherche

Structures organisationnelles

Fonction

Nom de famille

Cloutier

Prénom

Alain

Affiliation

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

ISNI

ORCID

Identifiant Canadiana

ncf10407795

person.page.name

Résultats de recherche

Voici les éléments 1 - 10 sur 10
  • 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
    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.
  • PublicationRestreint
    Particleboard made from hammer milled black spruce bark residues
    (Springer, 2000-03-01) Riedl, Bernard; Cloutier, Alain; Blanchet, Pierre
     The disposal of bark residues is an important problem for the forest industry. An important proportion of the bark produced by the paper and lumber industries is used for energy production, but a significant amount of bark is still unused. The objective of this study was to determine the technical feasibility of making particleboards from black spruce bark residues bonded with urea formaldehyde resin and meeting the indoor performance requirements for wood particleboards. In the positive case, this would define a new use for black spruce bark residues. Fresh black spruce bark residues were obtained from a sawmill located in the northeast part of the province of Quebec, Canada. The bark was kiln-dried at 60 °C, the particles were generated from a hammermill and sieved. Particles from 0.02 to 2.0 mm were used in the surface layers and particles from 2.0 to 6.0 mm were used in the core layer. Particleboards of 540 × 560 × 16 mm were made with a laboratory hot press following a factorial design with two manufacturing variables at three levels: (1) wood particles content of the surface layers (0, 25, 50 percent); and (2) UF resin content of the surface layers (12, 14 and 16 percent) with a UF resin content in the core of 8 percent. This resulted in a factorial design of 9 different combinations repeated 3 times for a total of 27 boards. It was observed that the heating kinetics varied according to the wood particles content in the surface layers. The compression ratio of the mat and the board internal bond, modulus of elasticity, modulus of rupture, linear expansion and thickness swell were determined. The results show that it is technically possible to make particleboard from bark residues meeting the American National Standard Institute indoor requirement for wood particleboard under certain conditions. The modulus of rupture of the boards was the most critical property in this study. The best mechanical properties were obtained with a 50 percent wood content and 14 percent resin content in the surface layers. The particleboards produced in this study did not meet the minimal requirements for linear expansion. The temperature measurements performed in the core of the mat during hot pressing show that heat transfer improves with an increase in wood particles content in the surface layers.
  • PublicationAccès libre
    Effect of strand geometry and wood species on strandboard mechanical properties
    (Society of Wood Science and Technology], 2009-07-01) Beck, Katherina; Cloutier, Alain; Salenikovich, Alexander; Beauregard L., Robert
    This study compared the performance of strandboards made from trembling aspen, a lowdensity hardwood species, with strandboards made from paper birch, a medium-density hardwood species. Strands were cut into three different lengths (78, 105, and 142 mm) and two thicknesses (0.55 and 0.75 mm) to compare the impact of species, strand geometry, specific surface, and slenderness ratio. Internal bond (IB), modulus of elasticity (MOE), and modulus of rupture (MOR) for flatwise and edgewise bending, compressive strength, and stiffness were all determined. Both species performed equally well in IB (0.73 MPa for both species combined). The highest MOE and MOR values in flatwise and edgewise bending were obtained for long, thin strands and were significantly lower for birch than for aspen panels (flatwise: 13.6 GPa and 99.2 MPa for aspen and 12.1 GPa and 85.5 MPa for birch; edgewise: 13.5 GPa and 66.3 MPa for aspen and 13.2 GPa and 65.7 MPa for birch). Short aspen strands resulted in the highest compressive properties, slightly higher than those of short birch strands (aspen: compressive strength 10.4 MPa and stiffness 1.22 GPa; birch: 10.8 MPa and 2.25 GPa, respectively). Strand length must therefore be a compromise between the need for high bending properties provided by long strands and the need for high compressive properties provided by short strands.
  • PublicationRestreint
    Determination of the effective water conductivity of red pine sapwood
    (Springer, 2000-01-31) Cloutier, Alain; Tremblay, Carl; Fortin, Yves
    The instantaneous profile method was used to establish the boundary desorption curve of the effective water conductivity function of red pine (Pinus resinosa Ait.) sapwood in the radial and tangential directions from nearly saturated to dry conditions at 18, 56 and 85 °C. The results obtained demonstrate that the effective water conductivity is a function of moisture content, temperature, and direction of flow. The effective water conductivity increases by several orders of magnitude (104–105) as moisture content increases from dry to nearly saturated conditions at a given temperature. The effective water conductivity also increases by a factor varying between 10 and 50 as temperature rises from 18 to 85 °C in the moisture content range considered. The variation of the moisture content–water potential relationship with temperature can explain part of the temperature effect. The effective water conductivity was generally higher in the radial direction than in the tangential direction in a ratio varying from about 1/1 to 3/1 depending on moisture content and temperature. Finally, the flux–gradient relationships obtained at given moisture contents were found to be linear, confirming the validity of using a moisture flux equation considering the water potential gradient as the driving force for the experimental conditions considered in the present work. The knowledge of the effective water conductivity function and of the moisture content–water potential relationship allows the utilization of a two-dimensional model of moisture movement in wood during drying using the gradient in water potential as the driving force for drying at temperatures up to 85 °C.
  • PublicationRestreint
    Longitudinal and transverse permeability of balsam fir wetwood and normal heartwood
    (Society of Wood Science and Technology (U.S.), 2000-04-01) Cloutier, Alain; Lihra, Torsten; Zhang, S. Y.
    The occurrence of wetwood in balsam fir is a problem in the drying of sawn lumber: drying time increases and moisture content of dried lumber is heterogeneous. Permeability may be used as an indicator of drying rates. Longitudinal, radial, and tangential intrinsic permeability of balsam fir wet-wood and normal heartwood was measured in this study. The longitudinal intrinsic permeability was about 2,000 times and 9,000 times higher than the tangential and the radial intrinsic permeability, respectively. Wetwood had a higher longitudinal permeability than normal heartwood, but no significant difference was found between the radial and tangential directions. Sampling height in the tree, basic density, and growth ring width had no effect on the intrinsic permeability. An increase of latewood percentage in the growth rings resulted in an increase in longitudinal intrinsic permeability and a decrease in tangential intrinsic permeability. Radial flow seemed to be controlled by ray blockage in wetwood and normal heartwood, which may result in radial impermeability of wood. A poorly drained stand seemed to favor wetwood formation.
  • PublicationRestreint
    Modeling vacuum-contact drying of wood : the water potential approach
    (2007-05-10) Defo, Maurice.; Cloutier, Alain; Fortin, Yves
    A two-dimensional mathematical model for vacuum-contact drying of wood is presented. The moisture and heat equations are based on the water potential concept whereas the pressure equation is formulated considering unsteady state conservation equation of dry air. Most of the model parameters were determined during independent experiments. The set of equations is then solved in a coupled form using the finite element method. The validation of the model is performed using experimental results obtained during vacuum-contact drying of sugar maple sapwood. The experimental and calculated data are in good agreement. Nevertheless, some discrepancies are observed which can be attributed to the boundary conditions used and to the fact that heat transfer by convection was neglected.
  • PublicationRestreint
    Characterization of juvenile wood to mature wood transition age in black spruce (Picea mariana (Mill.) B.S.P.) at different stand densities and sampling heights
    (International Academy of Wood Science, 2005-11-24) Cloutier, Alain; Alteyrac, Jérôme; Zhang, S. Y.
    The radial pattern of both maximum ring density and ring area of 36 black spruce trees were used to determine the transition age from juvenile wood to mature wood. The data were obtained by X-ray densitometry and both segmented linear and polynomial regressions were used to point out the age of the juvenile wood boundary. Three stand densities (1,790, 2,700 and 3,400 stems/ha) and three sampling heights (2.4, 5.1 and 7.8 m) were studied. Although maximum ring density and ring area presented similar radial patterns, they gave two significantly different results of transition ages. The maximum ring density over-estimated the transition age (17.6 years) in contrast to ring area (14 years). The results show that the transition from juvenile wood to mature wood occurred after 12 years at 7.8 m (versus 13.1 years at a height of 5.1 m, and 17.6 years at 2.4 m). Although transition age occurred later in the high stand density group (21 years), the difference was not significant between the three stand density groups. Nevertheless, transition age remains difficult to determine since no standard definition exists. The transition occurs over years, and most probably a transition wood exists between juvenile wood and mature wood. Estimation of the juvenile wood proportion in volume shows that it remains constant along the stem and it increases with stand density.
  • PublicationRestreint
    Experimental determination of the convective heat and mass transfer coefficients for wood drying
    (Springer., 2000-01-31) Cloutier, Alain; Fortin, Yves
    The knowledge of the convective heat and mass transfer coefficients is required for the characterization of the boundary conditions of the heat and mass transfer equations of a wood drying model based on water potential. A new experimental method for the determination of the convective mass transfer coefficient is presented. This method is based on the measurement of the moisture content, and indirectly the water potential, at the surface of a wood specimen at different drying times. Drying experiments were performed on red pine (Pinus resinosa Ait.) sapwood from nearly saturated to dry conditions at 56 °C, 52% relative humidity and air velocities of 1.0, 2.5 and 5.0 m s−1. The results show that the convective mass transfer coefficient is constant until the wood surface moisture content reaches about 80% and then decreases more or less gradually as the moisture content decreases further. The convective mass transfer coefficient increases with air velocity. A regression analysis shows that there is no significant improvement in considering the water potential gradient near the wood surface when the difference in water potential between the surface and the surrounding air (ψs − ψ∞) is used to determine the convective mass flux at the surface. Also, ψs − ψ∞ is more appropriate than the water vapour pressure difference (pvs − pv∞) as the responsible driving force of the moisture flux leaving the wood surface. The convective heat transfer coefficient was determined during the same experiments. A plateau is observed at high values of moisture content corresponding to the constant drying rate period.
  • PublicationRestreint
    Effects of fiber characteristics on the physical and mechanical properties of wood plastic composites
    (Elsevier, 2009-06-10) Bouafif, Hassine; Cloutier, Alain; Koubaa, Ahmed; Perré, Patrick
    We investigated the effects of fiber variability, size, and content on selected mechanical and physical properties of wood plastic composites. HDPE and fibers were compounded into pellets by twin-screw extrusion and test specimens were prepared by injection molding. All tested properties vary significantly with fiber origin. Higher fiber size produces higher strength and elasticity but lower energy to break and elongation. The effect of fiber size on water uptake is minimal. Increasing fiber load improves the strength and stiffness of the composite but decreases elongation and energy to break. Water uptake increases with increasing fiber content.