Wood and Fiber Science (E-Journal)
Not a member yet
2592 research outputs found
Sort by
Effect of Material Properties and Anchorage Location on Load-Bearing Capacity of Screw-Connected and Hung Cabinets
No full textEffects of material type and thickness of selected wood-based composites for construction of cabinets and anchorage location of screws attaching cabinets to the wall on the vertical load-bearing capacity of four-sided wall cabinets were investigated. Experimental results show that screw anchorage location significantly affected the load-bearing capacity of four-sided wall cabinets. Cabinets anchored to the wall from their sides had a significantly higher vertical load-bearing capacity than the ones anchored to the wall from their top. Plywood (PLY) cabinets had a significantly higher vertical load-bearing capacity than medium-density fiberboard (MDF) and particleboard (PB) cabinets. MDF cabinets tended to have higher vertical load-bearing capacities than PB, but the significance was affected by screw anchorage location and material thickness. The vertical load-bearing capacity of PB cabinets was governed by its material modulus of rupture (MOR) and density, whereas MDF cabinets anchored from the sides were governed by their material internal bond strength and MDF cabinets anchored from the top by their material MOR and thickness. The vertical load-bearing capacity of PLY cabinets was dominated by material thickness only
Technical Note: Evaluation of a Crucible Furnace Retort for Laboratory Torrefactions of Wood Chips
Get PDFTorrefaction is a thermal process that improves biomass performance as a fuel by property enhancements such as decreased moisture uptake and increased carbon density. Most studies to date have used very small amounts of finely ground biomass. This study reports the testing of a crucible furnace retort that was fabricated to produce intermediate quantities of torrefied material and to allow processing of wood chips. Yields ranging from 51 to 96% were impacted to a greater extent by differences in temperature than time of treatment. Although temperature-control issues (gradients, slow heating) were experienced with the crucible furnace retort, this equipment proved to be useful for its intended purpose
Structure of Cellulosic Fiber-Derived Carbon Catalyzed by Iron Oxide Nanoparticles
No full textCatalytic graphitization of iron oxide-nanoparticle-coated cellulosic fibers from wood is presented in this study. Bleached cellulosic fibers coated with iron oxide nanoparticles and the control samples were pyrolyzed at five elevated temperatures: 800, 1000, 1200, 1400, and 1600°C. The structure changes of the fibers were examined by scanning electron microscope, X-ray diffraction (XRD), and Raman spectroscopy. The results showed that the graphitization of cellulosic fibers was accelerated during the pyrolysis process by the introduction of iron oxide nanoparticles. The results from XRD and Raman spectroscopy confirmed that at a temperature of greater than 800°C, a cellulosic fiber graphitic structure started to change on the iron oxide-nanoparticle-coated cellulosic fiber samples. A significant increase in the graphitic structure was shown at 1200°C
2010 Status Quo for Life Cycle Inventory and Environmental Impact Assessment of Wood-Based Panel Products in Germany
Get PDFConsidering the importance of the German wood-based panel industry, the current status of available life-cycle inventory (LCI) data for these products is quite unsatisfying. In this study, detailed disaggregated LCI and environmental life-cycle assessment (LCA) data and variation in data on production of the core products of the German wood-based panel sector are given. The data suit a wide range of applications and are transparently documented, allowing consistent combination with other raw data sets. The data are analyzed in terms of sensitivity of environmental impacts to the variations in LCI. Also, specific advice is given to LCA practitioners on how to narrow the presented variations with respect to the environmental impact category they are interested in. Results are presented for the typical midpoint environmental impact categories excluding toxicity indicators. For the latter, the relevant data gaps are discussed
Microstructure and Adsorption Property of Bamboo-Based Activated Carbon Fibers Prepared by Liquefaction and Curing
Get PDFIn this study, activated carbon fibers (BACF) were prepared from moso bamboo by phenol liquefaction, spinning, curing, and CO2 activation. The microstructure and porous texture of BACF were investigated by Fourier transform IR spectroscopy, X-ray diffraction, and N2 adsorption at -196°C. The surface area and pore volume increased progressively after activation, and yields were found in the range of 39-59.6%. BACF showed type I isotherms with multimodal pore size distributions in th
Localized Modulus of Elasticity in Timber and Its Significance for the Accuracy of Machine Strength Grading
Get PDFFrom previous research, it is well known that a localized modulus of elasticity (MOE) is a better indicating property (IP) of strength than an MOE averaged across a longer span. In this study, it was investigated to what extent the relationship, in terms of coefficient of determination (R2), between strength and localized MOE was dependent on the length across which the MOE was determined. Localized MOE was calculated with MOE profiles based on dot laser scanning of fiber directions, axial dynamic excitation, and a scheme of integration across a board's cross-section. Two board samples were investigated. Maximum R2 values, which were as high as 0.68 and 0.77, respectively, were obtained for localized MOE determined across lengths corresponding to about half the depth of the investigated boards. Consequently, application of a highly localized bending MOE as an IP will result in very competitive grading
Characterization of Chemical Wood Modification with Melamine-Urea-Formaldehyde Prepolymer on Fast-Growing Wood
No full textTo improve their overall performance, fast-growing poplar logs were modified by impregnation with a melamine-urea-formaldehyde (MUF) prepolymer. The results showed that density, dimensional stability, and mechanical properties of fast-growing poplar were markedly improved. The vertical density profile curves confirmed the even distribution of wood modifier in wood cells after impregnation. The water uptake for 72 h improved from 118.5 to 77.2%. Meanwhile, swelling of the modified wood in cross-section, radial section, and volume was decreased to 2.6, 3.1, and 4.8%, respectively. Significant improvements occurred in wood mechanical properties such as bending strength, compressive strength parallel to grain, modulus of elasticity in static bending, and hardness. The mechanism of modification was characterized by X-ray diffraction (XRD), Fourier transform IR spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDXA). Dynamic mechanical analysis showed that the storage modulus value of wood samples increased from 6.4 to 7.48 GPa. XRD showed that crystallinity of wood increased and formed a quasi-crystalline. FTIR analysis demonstrated that a chemical crosslinking reaction existed between the function groups of -NHCH2OH from the MUF prepolymer and the wood carboxyl C=O. Finally, SEM-EDXA indicated good dispersion of the modifier in wood fiber and other vertical cells
Acoustic Emission of Bolt-Bearing Testing on Structural Composite Lumbers
No full textAcoustic emission (AE) characteristics of full-hole bolt-bearing testing on structural composite lumbers (SCL) including laminated veneer lumber (LVL) and oriented strand lumber (OSL) were investigated. The main conclusion is that AE cumulative counts vs time curves of the tested SCL in this study can be characterized with three distinct regions in terms of AE count rates: Region I with a lower constant count rate, Region II with varied and increased count rates, and Region III with a higher constant count rate. Differences in AE count rates of these three regions occurred between LVL and OSL. Also, within each tested SCL, differences in AE count rates were observed among the three regions. These differences in terms of AE count rates between two tested SCL indicate that different types of wood-based composites might have different AE characteristics in terms of the count rate changes when they are subjected to increased bolt compression load. In other words, these differences in AE characteristics between the two tested materials suggest AE "signatures" do exist for SCL bolt connections
Characterization of Surface Chemical Heterogeneity of Cellulosic Fibers
No full textIn this study, the surface chemical heterogeneity and surface physical properties of single wood pulp and rayon fibers were investigated. Wetting force traces along the fiber length were obtained by applying the Wilhelmy technique to individual fibers. A parameter called the heterogeneity index was developed from advancing and receding wetting force traces via a cubic spline statistical routine and has been shown to be a meaningful parameter to quantify the surface heterogeneity of fibers. This was done for both "as is" wood pulp and rayon fibers and wood pulp treated with various dosages of the commercial sizing agents alkyl ketene dimer (AKD) and alkenyl succinic anhydride (ASA). The results indicated that the surface chemical heterogeneity index of AKD-sized fibers increased with AKD dosage, whereas the surface roughness of fibers remained virtually unchanged. This heterogeneity index is useful to more fully understand macroscopic sizing behavior of paper sheets beyond simply the value of a single fiber average advancing contact angle
Sol-Gel Deposition of TiO2 Nanocoatings on Wood Surfaces with Enhanced Hydrophobicity and Photostability
No full textTo enhance the resistance of wood against weathering, Chinese fir (Cunninghamia lanceolata) wood was modified via a two-step process by first growing titanium dioxide (TiO2) nanocoatings on the wood substrate using a sol-gel process followed by low-surface free-energy treatment with hydrolyzed hexadecyltrimethoxysilane (HDTMS). The morphology and chemical composition of the formed coatings were examined by field-emission scanning electron microscopy, energy dispersive X-ray analysis, and Fourier transform IR spectroscopy. Water contact angle (WCA) was used to characterize hydrophobicity. UV-Vis spectroscopy and accelerated weathering were used to evaluate the UV-shielding properties of the nanocoatings and the photostability of the treated wood, respectively. The results showed that the introduction of TiO2 nanoparticles facilitated the generation of a dual-size roughness on the wood substrate, and the long-chain alkyl groups of HDTMS were covalently linked to the surface of the particles. The WCA of the treated wood was improved remarkably up to ≈138° displaying high hydrophobicity. The TiO2 coatings also exhibited strong absorption of UV radiation and imparted the underlying wood substrate with enhanced photostability, which was highly dependent on the TiO2 loadings in the coatings