Volume 16 Issue 1

An important wood species in the furniture and parquet industry today is “doussie” wood. In this study, the effects of artificial weathering on ultraviolet-cured varnish (3 coats and 5 coats) applied to doussie (Afzelia africana) wood were investigated. The samples of the UV system cured varnishes were exposed to aging effects for 252 h and 504 h via an UV-A 340 nm lamp. The coated specimens were exposed to UV-A 340 nm fluorescent lamp in a QUV accelerated weathering tester for 252 h and 504 h. The surface adhesion strength, color (L*, a*, b*, ∆E*, ∆L*, ∆a*, and ∆b*) parameters, pendulum hardness, and glossiness (parallel (//) and perpendicular (⊥) at 20°, 60°, and 85°) of UV varnishes coated samples were quantified before and after weathering. According to the results, while the a* value increased, the adhesion, L*, b*, and glossiness values decreased with aging. As a result, it was concluded that doussie wood can be used in the production of flooring with UV-cured varnish.

The promotional effect of Zn was investigated relative to the calcining activation of HZSM-5. It was found that the lignin separated from walnut shell could be liquefied into small molecular ethers such as anisole by the promotional effect of the modified catalyst. Experimental results showed that, after the loading of Zn, the HZSM-5 catalyst retained its original crystal structure, which exhibited good metal dispersion. Besides, due to the existence of two interactions respectively of Zn with Al and Zn with a Brønsted-Lowry acid on the Zn/HZSM-5 catalyst surface, the remaining catalyst intergranular distance increased, particularly for the 2% Zn/HZSM-5 catalyst. The inside of the catalyst was in a state of spherical particle aggregation with a narrow pore size distribution and uniform particle size. The peak intensity of the Si-O stretching vibration was affected by the content of Zn, which was least affected for the 2% Zn/HZSM-5 catalyst. The signal peak of this small molecule ether was not found in the absence of the metal ions, and the catalytic effect of 2% Zn/HZSM-5 was more distinct. Calculated by the mass difference method, the yield of the liquid via the 2% Zn/HZSM-5 catalyst was 59.8%, including phenol and small molecule ethers represented by anisole.

This study investigated the effect of accelerated weathering conditions on total color changes on Scots pine (Pinus sylvestris L.) and poplar (Populus x euroamericana) wood surfaces using the Taguchi method. The experiments, based on the L18 orthogonal array, were conducted separately for both tree species. The radial and tangential surfaces of wood specimens were subjected to an accelerated weathering process using 340 nm ultraviolet (UV) lamps and temperature conditions of 50 °C. The factors for the minimum color change were determined via the signal-to-noise (S/N) ratios of the four parameters thought to be effective on color change. These parameters were cutting direction (two levels), UV-irradiance, conditioning, and water (three levels each). The most important factor affecting the color change was then determined by analysis of variance (ANOVA) testing. The results showed that the maximum UV-irradiance (W/m2) had the largest effect on the total color change, while the cutting direction (radial and tangential) had the smallest effect. The factors that affected the total color change of the poplar and Scots pine wood specimens were the same. However, the analysis revealed that different application times had varying effects on the color change.

The manufacturing of a sandwich structure engineered wood, constructed from a rice husk flake core and teak veneer as outside skins, was studied in this work. Epoxy adhesive was employed, while glass and carbon fiber, both short discontinuous and woven forms, were used as reinforcement. The impact strength, flexural properties, and dimensional stability of the samples after prolonged water immersion were measured. At the assigned reinforcement loadings, the rice husk flake/woven woods showed mechanical superiority over the rice husk flake/short discontinuous materials, regardless of the fiber type. The reason for the greater rice husk flake/woven interfacial adhesion and laminated woven strength, compared to the rice husk flake/short discontinuous composite was investigated. The samples constructed from teak veneer laminated with woven glass or carbon fiber skin and rice husk flake or rice husk flake/30% woven glass cores had greater mechanical properties. The high shear and tensile/compression stresses of woven glass or carbon fiber laminated onto teak veneer skins were confirmed. The sandwich structure engineered wood using woven glass and carbon fiber reinforcement exhibited good dimensional stability under prolonged water immersion. Carbon fiber was the better material candidate compared to woven glass in terms of manufacturing the sandwich engineered wood presented in this work.

Effects of incising parameters were studied relative to the drying performance and properties of super–fast dried oil palm wood. Different incising depths (1/3, 1/2, 2/3, and 100% of the total thickness) and distance (38 mm and 50 mm) were made on the oil palm wood boards prior to the super-fast drying procedure. All the boards achieved the desired moisture content after drying. Drying defects were minimal, as only two boards indicated end checks and surface checks defects. The board density ranged from 0.44 g/m3 to 0.60 g/m3, and the thickness swelling and water absorption of the boards ranged from 8.3% to 12.5% and 45% to 67%, respectively. The specific modulus of rupture and elasticty ranged from 0.35 N m3/kg mm2 to 0.77 N m3/kg mm2 and from 77.64 N m3/kg mm2 to 118.40 N m3/kg mm2, respectively. It can be concluded that the hole distances did not exert significant effect on the properties, with exception of specific modulus of elasticity. A hole depth of 1/3 mm was preferable, since the surface looked like no incision had been made and the sample had good physical and flexural properties.

Brewer’s spent grain (BSG) is the main solid by-product of the brewing sector. High moisture and nutrient-rich content render BSG easily perishable, leading to waste generation and environmental impacts. BSG has narrow applications in both feed and food sectors due to its composition including high fiber and low protein. Therefore, a processing strategy leading to the nutritional valorization of BSG could widen its applications. In this study, submerged cultivation of edible filamentous fungi (Aspergillus oryzae, Neurospora intermedia, and Rhizopus delemar) was introduced as a strategy to enhance the protein content of BSG. The growth of all strains in BSG increased the protein content of the fermented BSG. The highest increase of protein content (from 22.6% to 34.6%), was obtained by cultivation using A. oryzae and medium supplementation. The protein content increase was followed by a decrease in the content of polysaccharides (up to ca. 50%), namely starch, glucan, xylan, and arabinan. The addition of cellulase resulted in enhanced ethanol production from BSG but led to lower concentration of recovered solids. In conclusion, simple processing of BSG using edible filamentous fungi can lead to quality improvement of BSG, providing potential economic and environmental benefits to the brewing sector.

An aluminophosphate adhesive was used as the binder in plywood. The hot-pressing parameters of aluminophosphate adhesive-based plywood (APPs) including hot-press temperature (A), time (B), and pressure (C) were optimized using response surface methodology. Results indicated that the hot-press temperature was the most dominant factor. The maximum bonding strength of 1.98 MPa was found with an optimal parameter of 171 °C (hot-press temperature), 7.5 min (hot-press time), and 1.0 MPa (hot-press pressure). Additionally, the chemical reaction mechanism between aluminophosphate adhesive and wood fibers was characterized by X-ray photoelectron spectroscopy (XPS). Results showed that good interaction was generated between wood fibers and adhesives through their surface functional groups. In conclusion, the optimized pressing conditions of plywood significantly improved bonding strength of APPs.

Microcrystalline cellulose was oxidized via periodate followed by sulfonation. The sulfonated cellulose nanocrystals were obtained through centrifugation, dialysis, and sonication. The sulfonated cellulose nanocrystals were rod-like and had an average length of 140 nm to 153 nm and an average width of 8 to 10 nm. The Fourier transform infrared profiles and polyelectrate titration demonstrated successful introduction of the sulfonated groups into the cellulose nanocrystals. The sulfonated cellulose nanocrystals had a higher crystallinity index than dialdehyde cellulose. The thin films fabricated via the casting of the sulfonated cellulose nanocrystals suspensions were highly hydrophilic.

The controlled release of bergamot oil was evaluated from rubberwood boxes containing activated carbon and bergamot oil. Rubberwood boxes impregnated with different concentrations of bergamot oil (50, 100, and 300 µg g−1) with and without activated carbon were prepared. The treated rubberwood boxes were utilized to store strawberries at 6 °C for 21 d, while boxes with only activated carbon were used as a control. The inhibitory effects relative to Botrytis cinerea growth and quality of the strawberries after storage in rubberwood box were investigated. The microstructure of the rubberwood was evaluated via scanning electron microscopy. Gas chromatography mass spectrometry was used to quantify the volatile compounds. The rubberwood boxes with activated carbon and 100 µg g−1 of bergamot oil were found to inhibit Botrytis cinerea growth on strawberries and extend their shelf life for at least 21 d. Compared to rubberwood boxes without activated carbon, activated carbon was able to retard the release of bergamot oil into the system, yielding increased strawberry quality. Releasing less bioactive components from bergamot oil could decrease undesirable effects on strawberries, e.g., tissue, weight loss, flavour, and colour changes.

To improve the comprehensive utilization of planting and breeding waste resources, corn straw and cow manure were used as raw materials for exploring the molding process parameters for preparing agricultural fertilizers via compression after mixing. The pressure, compression speed, and holding time were the experimental factors, while the block drainage, compression ratio, and dimensional stability were used as evaluation indicators. This study analyzed the influence of various factors on the quality evaluation index of the formed blocks. The results show that the best factor ranges were as follows: a pressure of 15 kN to 24 kN, a compression speed of 200 mm/min to 400 mm/min, and a holding time of 30 s to 60 s. A ternary quadratic regression and rotating-combination test design was used to optimize the combination of forming parameters as well as performing test verification. The formed block yielded the following results: a block drainage of 6.29%, a compression ratio of 3.37, a dimensional stability of 86.5%, a pressure of 23.9 kN, a compression speed of 276 mm/min, and a holding time of 53.1 s. These results can provide a reference for the molding process and equipment development of corn straw and cow manure mixed fertilizer.