Volume 10 Issue 3

Many wood product manufacturers are trying to increase competitiveness by implementing continuous improvement programs such as lean manufacturing. However, the lumber drying process can significantly affect manufacturing time and inventory size, thus limiting how “lean” the entire process can become. The goal of this research was to determine how vacuum drying technology could support lean manufacturing concepts relative to conventional drying technology in hardwood manufacturing. Two flooring manufacturers with drying operations were modeled, and simulations were used to determine differences in cycle time and work-in-process inventory. The total cycle time of vacuum drying was 78% and 90% less than conventional drying. Work-in-process inventory was reduced by 57% and 52%. The reduction of work-in-process inventory in the drying process represents a potential cost savings of $7.3 million and $13.6 million per year for each manufacturer, respectively. The reduction in inventory carrying costs, faster drying rates, and reduced cycle time demonstrate that vacuum drying could significantly improve the competitiveness of hardwood flooring manufacturers.

In this study OSB strands produced by a CAE 6/36 disk flaker from re-saturated moso and guadua bamboo tissue were classified by surface quality and compared with industrial aspen OSB strands. Strands were first classified into three groups based on surface appearance and texture. The topographic features that characterize the surface were then measured using a laser surface profiler to give two surface roughness indicators; average roughness (Ra) and average maximum roughness (Rz). Guadua strand surface quality was extremely poor compared to moso due to its very large, dense vascular bundles. Ra and Rz values for many bamboo strands, particularly guadua, exceeded the typical diameter of resin droplets dispensed during industrial OSB blending, meaning that excessive roughness could compromise bonding efficiency in bamboo OSB.

Hydrothermal carbonization (HTC) of lawn grass was carried out at 200 °C and 240 °C for 30 to 180 min. The chemical, energetic, and structural characteristics of HTC solid residues were investigated. Results from HTC experiments indicate that solid mass yield of all solid residues was 31 to 50%. The hydrogen/carbon (H/C) and oxygen/carbon (O/C) atomic ratios of all solid residues were 1.17 to 1.64 and 0.45 to 0.65, respectively. The higher heating value (HHV) increased up to 20.54 MJ/kg with increasing HTC residence time at 240 °C for 180 min. Both XRD patterns and FTIR spectra show that differences occur with samples treated as compared to the raw material. Solid hydrochar exhibited higher ordered structure characteristics and was mainly derived from amorphous components degradation when the residence time was increased from 30 to 180 min at 200 °C, while hydrochar formed from cellulose components degradation with increased residence time at 240 °C. According to the results studied, it was found that prolonged residence time was favorable to the formation of hydrochar from lawn grass.

High-pressure molding at an elevated temperature was investigated as a potential technique for performing the esterification of octanoïc acid and octanoïc anhydride on cellulose and miscanthus. Emulsion, solvent exchange, and high-pressure homogenizer pretreatments were performed on the reactants in order to improve liquid-solid contacts. After pretreatment, cellulose or miscanthus and octanoïc acid or octanoïc anhydride were molded at 220 MPa and an elevated temperature. The mechanical properties of the resulting compressed materials were measured, and the material was then ground and washed; the water drop angle was measured, and IR analysis was performed, as well as an accurate measure of the degree of substitution. The esterification reaction was confirmed, the water properties of the grafted cellulose were modified, and the mechanical properties of the modified materials were altered. From this pioneering work, a better understanding of the effect of the molding process on the reaction and production of water-resistant compressed cellulose materials was developed.

Rice bran oil was extracted using hexane, as well as subcritical butane and propane. The quality of rice bran oils obtained using these three solvents was comparatively studied. The results showed that subcritical fluid extraction oil showed higher concentrations of health-conducive components (such as vitamin E, oryzanol, and phytosterol) compared with hexane-extracted oil. Extraction solvent had an important effect on the distribution of linoleic acid and oleic acid. The sterol compositions in rice bran oils were identified to be composed of ethyl iso-allocholate, campesterol, stigmasterol, sitosterols, and cyclolanosts. NMR data showed that butane-extracted oil had the highest triacylglycerols (TAGs) content and that subcritical propane-extracted oil had the highest wax content among the oils extracted with these three extraction solvents. The oils extracted by subcritical butane and propane showed higher oxidative stabilities. These results indicate that subcritical fluid extraction technology could be a useful method for producing high-quality rice bran oils and could become widely used in industrial applications.

The objective of this paper was to investigate the warping and surface checking of engineered wood flooring that was exposed to a heating system. The effects of decorative veneer type, wood structure, and wood shape on warping and surface checking were studied in a laboratory with a simulated heating system. Poplar/seven layer plywood engineered hardwood (structure C) or a 9 mm think poplar substrate layer wood was used, which contained the two veneer surface layers, structure A and structure B. For each structure, two shapes (mono-block or three splice) were tested, and a total of eight different veneer wood types were used. The highest degree of warping was seen in Eucalyptus or sapele veneer types. The degree of warping was the greatest for structure C with mono-block, followed by structure A with mono-block, structure C with three splice, and structure A with three splice. According to the surface checking tests for wood type, American ash, eucalyptus, maple, or birch exhibited the easiest wear, whereas, eastern black walnut exhibited the hardest wear. The surface checking tests revealed that the ranking from easiest to hardest wear was structure B, structure A, and structure C.

To effectively improve the strength of Plectocomia pierreana rattan cane without reducing its toughness, the cane was impregnated with a new water-soluble melamine-urea-formaldehyde (MUF) resin modified with low-molecular-weight polyethylene glycol (PEG), marked as PMUF. The PMUF synthetic process was optimized using an orthogonal test L9(34). Results showed that the dimensional stability, density, and most mechanical properties of modified canes were improved greatly. Compared with MUF, PMUF imparted the cane with higher anti-swelling efficiency (ASE), modulus of elasticity (MOE), modulus of rupture (MOR), and impact toughness. These improvements indicated that PMUF could effectively improve the cane’s dimensional stability and strength, while simultaneously retaining its flexibility. Based on a comprehensive evaluation, the optimum modification conditions were : PEG-400, PEG/Melamine mole ratio of 0.1, step-wise synthesis, and PMUF solution of 30%. The ASE of optimal modified canes reached 65.51%, and its mechanical properties such as the MOE, MOR, compressive modulus, and compressive strength increased by 135.61%, 129.01%, 106.22%, and 88.52%, respectively. Additionally, its impact toughness was only reduced by 6.85%. The PMUF modified P. pierreana canes is comparable to the commercial Daemonorops margaritae canes.

Beams strengthened with a composite material consisting of carbon and glass fibre stabilised with two types of adhesives were evaluated. The primary objective was to determine the technical attributes of joints, the maximum bending strength capacity, deflection, and modulus of elasticity. The reinforcement fibres tested were based on carbon and glass fibre. Epoxy and polyurethane adhesives were used for stabilising the fibres on a spruce timber beam. Composite beams glued in both a prestressed and non-prestressed condition were tested and then compared with non-reinforced control beams. A four-point deflection pursuant to EN 408 (1995) was used in the determination of the strength of the load-bearing construction beams based on composites, consisting of a fibre type, adhesive type, and spruce timber. This approach was applied to define the size of the construction beams and process the measurement results. Reinforcing construction beams with fibres applied in a prestressed condition resulted in an increase in the bending strength capacity by 31.6 to 44.4% compared with a non-reinforced solid timber construction beam. These construction elements, strengthened with carbon and glass fibre composites glued with epoxy and polyurethane adhesives, are suitable for applications that require bending resistance perpendiculary to the glued joint direction.

The potential for using cotton seed hulls (CSHs) and walnut shells (WSs) as new, essential substances for substrate preparation in the cultivation of Pleurotus ostreatus was studied. Substrates prepared with oak sawdust alone (OS) and with mixtures of OS and CSHs and WSs in different ratios were compared, and their effects on the earliness, total time, yield, and biological efficiency (BE) were determined. The nitrogen (N) content of the substrates prepared using CSHs and WSs alone was high, so the C:N ratio of the substrates diminished as the proportions of CSHs and WSs in the mixtures were increased. The highest yields were obtained from substrates containing the maximum amount of N. The highest yield and highest biological efficiency were obtained for a mixture of 25OS:75CSHs, indicating that the yield in the substrates increased as the amount of CSHs in the mixtures increased. The morphological characteristics were influenced by the various substrates and their various ratios. The properties of mushroom cultivation in bags were related to the nitrogen content, as indicated by the C:N ratios. The results indicated that CSHs and WSs could be used as new, essential substances in the preparation of substrates for the cultivation of Pleurotus ostreatus.

Bacillus amyloliquefaciens xylanase A (baxA), an endoxylanase (EC. 3.2.1.8) gene, was cloned through PCR using the genome of B. amyloliquefaciens as a template. The open reading frame of baxA was 642 bp, and the gene encoded a 213 amino acid protein with a predicted molecular mass of 23.3 kDa. reBaxA1 produced in Escherichia coli with the pET30a(+) vector (T7 lac promoter) formed inclusion body and did not show any xylanase activity. reBaxA2 produced in E. coli with the pCold TF vector (cspA lac promoter) showed high xylanase activity; this enzyme was secreted into the culture medium and remained in the cell. Sodium dodecyl sulphate–polyacrylamide gel electrophoresis analysis showed that the molecular weights of reBaxA1 and reBaxA2 were approximately 28.5 and 77.2 kDa, respectively. The optimal activity of reBaxA2 occurred at 55 °C and pH 6.0. Moreover, the Michaelis–Menten constant (Km) and maximal activity (Vmax) of reBaxA2 were 4.98 mg•ml-1 and 12.79 μmol•min–1•mL–1, respectively. High–performance liquid chromatography analysis showed that reBaxA2 released xylooligosaccharides from birchwood, beechwood, and oat spelt xylans, with xylopentaose, xylotriose, and xylotetraose as major products, respectively.