Wood and Fiber Science (E-Journal)
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EFFECT OF PROCESSING PARAMETERS ON THE SYNTHESIS OF LIGNIN-BASED GRAPHENE-ENCAPSULATED COPPER NANOPARTICLES
Get PDF Graphene-encapsulated copper nanoparticles (GECNs) can be applied in the wood protection industry. In this study, a simple thermal treatment was applied to a mixture of kraft lignin and copper sulfate for the synthesis of GECNs. The effect of temperature, duration time, temperature rising ramp, and argon gas flow rate were investigated on the quality of the GECNs. Temperature was found to be the most important factor in the growth of graphene; high temperature was preferred to obtain less defective graphene shells. Gas flow rate, duration time, and temperature rising ramp had less effect. The optimum synthesis parameters were proposed as 1000C, 30-min duration time, 20C/min temperature rising ramp, and 1200-sccm argon gas flow rate. Results showed that postheat treatment was a feasible way to improve the crystallinity of graphite.
Wood-rubber composite fabricated from rubber mixing and vulcanization molding process
Get PDFWood-rubber composites (WRC) has been successfully manufactured through rubber mixing and vulcanization molding process. The morphological properties of the composite panels were characterized using a scanning electron microscope (SEM). It showed that the wood powders were well embedded in the tire rubber matrix. The functional groups of the composites were observed by Fourier transform infrared spectroscopy. The curing characteristics were analyzed on the WRC fabricated with different wood powder loadings. The mechanical properties of the WRCS including, tensile strength, elongation at break, hardness and rebound resilience, were examined. It was determined that the wood powder loading should not be more than 50 wt %. Incorporation of wood powder increased the hardness of the WRC with about 53% improvement when the wood powder loaiding increased from 0% to 50%. The water absorption of the WRC was lower than that of traditional wood-based composites
Quantifying environmental impacts of poplar biomass production in the U.S. Pacific Northwest
Get PDFThe life cycle impacts were determined for poplar-managed four ways in the Pacific Northwest of the United States. Two sites had 3-yr rotations and either no irrigation (Site 1) or irrigation with river water (Site 2). The other sites had 12-yr rotations and irrigation with wastewater from a treatment facility (Site 3) or irrigation with landfill leachate (Site 4). Primary data for land preparation, plantation management, harvesting, and land restoration at each site and the production of cuttings at an additional facility were collected. A cradle to gate life cycle assessment was conducted using SimaPro PhD v8 based on the primary data and secondary data from the US life cycle inventory and ecoinvent v3 database to create a life cycle inventory. Impact indicators were provided by TRACI model. Short rotations resulted in lower global warming impact per unit output (79.5 and 54.5 kg CO2 eq/t) and energy consumption (1381.8 and 877.4 MJ/t) than long rotations (93.1 and 81 kg CO2 eq/t and 1406.9 and 1343.5 MJ/t) mainly due to reduced diesel use. Higher planting densities resulted in greater water and electrical consumption attributed to cuttings. Pesticide and herbicide use strongly affected ozone depletion and eutrophication, whereas fuel consumption had strong effects on global warming impact, smog, and acidification. Increasing biomass yield reduced impacts. When the electricity was all from biomass, global warming and acidification decreased; however, ozone depletion, smog, and eutrophication increased. The results suggested that both, herbicide application during plantation management and diesel consumed during harvesting at these sites should be optimized to decrease the environmental impacts.
EFFECT OF CUTTING PARAMETERS ON DUST EMISSION AND SURFACE ROUGHNESS DURING HELICAL PLANING RED OAK WOOD
Get PDFCutting parameters can influence the chip thickness and resulting dust emission and surface quality during wood machining. The purpose of this study was to evaluate the effect of cutting parameters on the airborne dust emission (0.1-15 μm) and surface roughness produced by helical planing red oak wood. Two cutting depths (0.5 and 1.0 mm) and eight feed speeds (from 6 to 20 m/min) were combined to obtain four average chip thicknesses (from 0.10 to 0.22 mm). The results showed that dust emission decreases as average chip thickness increases. Dust emission also increased for the higher cutting depth but for thinner chips (0.10 mm thick). For thicker chips, dust emitted was similar for the two studied cutting depths. Regression models for estimating dust emission for each particle size fraction as a function of average chip thickness and cutting depth were developed. Furthermore, higher values of average chip thickness produced higher surface roughness. The best helical planing condition was obtained when using 0.5-mm cutting depth, 0.18-mm average chip thickness, and 16 m/min feed speed. This condition was the fastest feed speed allowable to obtain the best surface quality while minimizing dust production.
MECHANO-SORPTIVE CREEP MECHANISM OF BAMBOO-BASED PRODUCTS IN BENDING
Get PDFThe phenomenon of mechano-sorptive (MS) creep is critical to structural design. It can result in greater deformation and earlier failure under cyclical moisture conditions. This study focuses on the MS bending creep of bamboo laminated veneer lumber (BLVL) and glued laminated bamboo (GLB). All samples were found to exhibit a large creep increment during moisture cycling compared with samples under constant humidity conditions. Relative creep increased with adsorption and showed a slight increase with desorption. However, in the modified creep, subtracting the elastic and shrinkage-swelling components of the total creep, a substantial decrease in absorption for the BLVL was observed, whereas the adsorption increased for the GLB. The creep limit of BLVL was 1.293 mm, and GLB’s limit was 3.363 mm.
FINE PARTICLES CONTENT IN DUST CREATED IN CNC MILLING OF SELECTED WOOD COMPOSITES
Get PDFThis paper presents the results of particle-size distribution of dust created in the milling of selected wood composites, which was carried out using a computer numerical control (CNC) machine. The particle-size distribution was studied through the sieving method and the laser diffraction analysis method. The results of the sieve analysis presented general information about the particle-size distribution of the dust, and the results of laser analysis revealed the content of the finest particles in the whole mass of dust created. The particle size of the dust is subject to the influence of the type of wood composite and the fragmentation degree of wood from which the composites are made. The dust created in milling of fibreboards is characterized by the highest content of the finest particles. It is also 2-3 times higher than in dust from drilling
ENVIRONMENTAL UTILITY OF WOOD SUBSTITUTION IN COMMERCIAL BUILDINGS USING LIFE-CYCLE ANALYSIS.
Get PDFWood is the predominant construction material in the US residential sector. In commercial and midrise construction, the use of wood is limited compared with reinforced concrete and steel. Wood, being a natural, renewable material that sequesters carbon, is a natural fit for newer construction with enhanced sustainability goals. The objective of this study is to evaluate and identify the environmental utility (avoided emissions) of using wood in place of steel and concrete in the commercial construction and renovation sectors in Oregon, United States. The study used comparative, cradle-to-grave, life-cycle analysis, with Athena Impact Estimator for Buildings. Six case studies that represent different building functionalities, material systems, and construction techniques were modeled via the user interface input option, and the results were evaluated for global warming potential (GWP) and impacts on energy sources, such as fossil fuel consumption, when structural materials are substituted using wood. Out of the six case studies, one building was completely redesigned as per current codes using wood as the major structural material. Bills of materials for both wood redesigns and the as-built designs were used as input in the software and subsequently analyzed. Results showed that the average reduction in GWP due to wood substitution was about 60% across the six case studies. These findings reinforce the perception of wood as a green building material having potential for commercial construction.