Wood and Fiber Science (E-Journal)
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EXAMINATION OF WORLDWIDE HARDWOOD LUMBER PRODUCTION, TRADE, AND APPARENT CONSUMPTION: 1995-2013
Get PDFWorldwide hardwood lumber production fluctuated between 1995 and 2013 and changed considerably with respect to regional market shares. Similarly, worldwide hardwood lumber imports and exports have been constantly changing. Understanding these changes is important because collectively, they define the hardwood lumber consumption of a region or country. In 1995, North America accounted for 25% of worldwide hardwood lumber production whereas East Asia and Oceana (EAO) produced 26%. In the current century, a decline in production in the United States and increased production in China and Vietnam resulted in the EAO region accounting for more than 48% of worldwide hardwood lumber production in 2013. Much of the international trade of hardwood lumber is carried out by EAO and European countries and is intraregional among countries within these regions. Hardwood lumber consumption generally has been moderately to poorly correlated with population at the country level since 1995 and uncorrelated with gross domestic product. However, several other factors also appear to affect current consumption including loss or gain of secondary hardwood industries, age of the population, urbanization, and in recent years, slow economic growth in countries with high per capita grossnational product
CHARACTERIZATION OF COPPER IN LEACHATES FROM ACQ- AND MCQ-TREATED WOOD AND ITS EFFECT ON BASIDIOSPORE GERMINATION
Get PDFThe unpenetrated interior of wood with a shell of preservative treatment may be exposed when the wood is cut or when checks open up. Mobile copper from wood shell-treated with chromated copper arsenate (CCA) has been shown to protect cut ends and checks against basidiospore germination. However, recent observations found that leachates from alkaline copper quat (ACQ)-treated wood failed to prevent basidiospore germination on untreated wood although copper levels were higher than toxic thresholds previously identified. It was hypothesized that the copper in leachate from ACQ-treated wood may be coordinated with monoethanolamine and/or lignin-based ligands and that this may result in poorer performance against basidiospores. In this study, electron paramagnetic resonance spectroscopy was used to determine the form of copper in leachates from ACQ, micronized copper quat (MCQ), and coppersulfate-treated wood. Leachates from ACQ-treated wood contained at least some degree of coordination with a nitrogen- and oxygen-containing ligand, probably monoethanolamine. This was not detected in leachates from MCQ and copper-sulfate-treated wood. These leachates were further evaluated for their ability to inhibit germination of Tyromyces palustris basidiospores. At low concentrations of copper, the CuSO4 and MCQ leachates were more effective than the ACQ leachate. At high concentrations CuSO4 and MCQ, leachates prevented germination in all samples, whereas ACQ leachates prevented germination in all but one sample
Erratum
No full textThe following corrections should be made to:Chen T, Niu M, Xie Y (2015) Optimizing preparation conditions of ultra-low-density fiberboard byresponse surface methodology. Wood Fib Sci 47(3):240–248.Table 1: Units for Internal Bond Strength should be kPa.Figure 2. The units should be changed to kPa
To What do Firms Attribute Success? An Application of Attribution Theory to the Secondary Woodworking Industry
No full textSmall firms are a critical component of the secondary woodworking industry and are important to hardwood lumber demand in the US. Understanding managers’ perceptions of competitiveness in these firms is important to those working with the industry to help maintain a viable wood manufacturing base. One area of interest relative to the overall business environment involves attribution: to what do managers attribute their firms’ success? In this study, attribution theory was applied to a sample of secondary woodworking manufacturers to test for a “self-serving” attribution effect (ie success is caused by internal factors, whereas a lack of success is caused by external factors), which has been shown in some other industries. Also of interest was determining if the effect was amplified for small firms. The presence of an overall attribution effect among secondary woodworking manufacturers was generally supported, but little evidence was found of an effect related specifically to small firms. The presence of an overall attribution effect is discussed in terms of the implications for research and outreach directed toward the secondary woodworking industry
Optimization of Mechanical Properties of Bamboo Plywood
No full textThis study describes a process to apply response surface methodology (RSM) together with a niched Pareto genetic algorithm for optimization of the mechanical properties of bamboo plywood. Experiments were carried out to investigate the dependences of parallel and perpendicular modulus of rupture (MOR) and modulus of elasticity (MOE) of bamboo plywood on hot-pressing temperature, hotpressing time, pressure, amount of adhesive, and moisture content. Empirical equations were presented to describe the dependences. Orthogonal tests and RSM were used to establish models for MOE and MOR of bamboo plywood in the parallel and perpendicular directions. Solutions of the models were obtained by means of a Pareto genetic algorithm. By comparing the solutions with given initial values, the optimized parallel and perpendicular MOR were increased by 19.52 and 23.35%, respectively, and the optimized parallel and perpendicular MOE by 21.50 and 12.57%, respectively. Based on the optimization, typical panel operational parameters were hot pressing temperature 163.3C, hot-pressing time 17.6 min, hotpressing pressure 4.0 MPa, amount of adhesive 8.9%, and MC 15.7%. Results from this study are useful to bamboo plywood mills for selecting operational parameters to determine mechanical properties of bamboo plywood, which will decrease workload and time in determining technical parameters to manufacture bamboo plywood with expected MOE and MOR
Melanization of the Wood-Staining Fungus Aureobasidium Pullulans in Response to UV Radiation
No full textAureobasidium pullulans is a dark yeast-like fungus that commonly colonizes weathered wood surfaces. We isolated black melanized strains of A. pullulans from weathered southern pine wood and also a less common white strain. In this study, we test if this white strain is a melanin-deficient strain or one that melanizes when it is exposed to UV light. White and black strains of A. pullulans were grown on artificial media under UV radiation, visible light, or in the dark for 7 days, and their color and melanin contents were measured. The white strain was lighter and produced significantly less melanin when grown in the dark than the black strain. However, the white strain melanized and became darker when grown under UV and visible light, and after 1 wk of exposure to UV light, its hyphal melanin content was similar to that of the black strain, although the latter had also melanized and become darker on exposure to UV light. We conclude that the white strain of A. pullulans we isolated from weathered wood is a strain with the adaptive ability to melanize after exposure to UV light
COMPRESSIVE CREEP AND RECOVERY BEHAVIORS OF SEAT CUSHIONS IN UPHOLSTERED FURNITURE
Get PDFThis study investigated effects of compressive load magnitude and cover and core materials on the force-deformation-time behavior of seat cushions commonly used in upholstered furniture. Results indicated that the Burger and Kelvin models could be used to describe the creep and recovery behavior of a furniture seat cushioning system composed of foam, spring, and cover materials, respectively. Statistical analyses of experimental data indicated that the magnitude of creep loads had significant effects on the viscoelastic constants in mathematical expressions derived from the Burger model for describing the force-deformation-time behavior of the cushions evaluated. Foam cushions with coil springs had significantly greater viscoelastic constants than those without. Changing cushion cover material from leather to fabric had no significant effect on the elastic constant of tested cushion materials, but increased theviscous constant and delayed elastic-deformation-related damping constants
Development of a Testing Protocol for Effects on Strength of Laboratory- Manufactured, Fire Retardant-Treated Strandboard
No full textThis research investigated the mechanical properties of laboratory-manufactured, fire retardanttreated (FRT) strandboard in an effort to establish laboratory testing protocols for these types of composite products. This study evaluates both the initial effects of fire retardant treatment and the effects of extended high-temperature exposure. Two sets of FRT and untreated strandboard panels were manufactured and tested. Preliminary work had assessed the effect of strandboard specimen width on the stability of mean and variance estimates obtained when testing matched treated and untreated specimens with four different widths. Those results indicated that use of ≥200 mm-wide strandboard specimens decreased both variation and error associated in mean estimates compared with testing narrower-width strandboard specimens. The findings in this study show that the testing protocols developed for laboratorymanufactured, FRT strandboard were both reproducible and adequately severe. These laboratory test methods successfully identified the potential initial strength effects on strandboard performance and their potential for secondary strength loss when exposed for an extended time in a high temperature environment minimizing the costs of using large commercial production facilities
OPTIMIZING PREPARATION CONDITIONS OF ULTRA-LOW-DENSITY FIBERBOARD BY RESPONSE SURFACE METHODOLOGY
Get PDFPreparation conditions of ultra-low-density fiberboard (ULDF) were optimized using the Box–Behnken design and response surface methodology. The effect and interactions of Si-Al molar ratio, additive amount of Si sol, and additive amount of Si-Al compounds on internal bond strength of ULDF were investigated. The regression model for ULDF preparation was significant ( p < 0.0001), and the Si-Al molar ratio and the additive amount of Si sol had a significant effect on internal bond strength, whereas the additive amount of Si-Al compounds did not. Optimum internal bond strength (12.68 ± 0.35 KPa) was achieved at 500 mL Si-Al compounds with Si-Al molar ratio of 2:1 and 20 mL Si sol. Fourier transform infrared spectra of the ULDF confirmed that some covalent bonds between Si-Al additives and fibers might be formed, and the thermal conductivity, noise reduction coefficient, and contact angle analysis of ULDF further confirmed the validity of the optimal preparation conditions
Comparative Properties of Bamboo and Pine Pellets
Get PDFBamboo is a biomass material that has great potential as a bioenergy resource of the future. To the best of our knowledge, there is a lack of sufficient information concerning bamboo pellets. Bamboo and pine pellets were therefore manufactured using a laboratory pellet mill. This study was carried out to compare and evaluate the properties of bamboo and pine pellets as biomass solid fuels. Bamboo pellets exhibited better combustion properties except for inorganic ash and worse overall physical properties than pine pellets. Most properties of both pellets were improved through carbonization treatment except for bulk and particle density. The properties of all pellets determined in this study met the requirements of Pellet Fuels Institute standards except for bulk density of bamboo pellets, and the gross calorific value also met the minimum requirement for producing commercial pellets of DIN 51731 (>17,500 J/g) (1996). The information from this study is helpful for evaluating properties of bamboo pellets and developing and using bamboo resources