BioResources (E-Journal)
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Application Parameters of Water Transfer Printing on Wood-based Panel Surfaces
No full textOptimum application values of the Water Transfer Printing (WTP) technique were determined on various wood-based panel surfaces. For this purpose, 8-mm-thick, glossy white, acrylic-coated medium-density fiberboard (MDF) panels (high gloss panels), polyvinyl chloride (PVC)-coated MDF panels, MDF Lam ready-to-use panels, and cellulosic, polyurethane, acrylic, and water-based paint applied MDF panels were used. An automatic immersion system with pool was designed and produced. A 30-μm-thick carbon patterned WTP film was applied on sample panel surfaces prepared with the help of this device at four immersion angles (0º, 15º, 30º, and 45º), four immersion speeds (50 cm/min, 100 cm/min, 150 cm/min, and 200 cm/min), and four immersion times (5 to 10 s, 20 to 30 s, 50 to 60 s, and 80 to 90 s). The optimum parameters of the WTP technique regarding the temperature and relative humidity of the application environment, water temperature, laying method, dissolution time, amount of activator, spray gun angle and tip clearance, air pressure, as well as immersion angle, speed, and time were determined using the measurement and observation method. According to the optimum parameters obtained in the study, the WTP technique was successfully applied to all wood-based panel surfaces
Ergosterol Supplementation Improves Furfural Tolerance of Saccharomyces cerevisiae to Produce Ethanol and Its Underlying Mechanism
No full textFurfural produced during lignocellulose pretreatment to reduce the recalcitrance inhibits the growth of Saccharomyces cerevisiae and reduces ethanol yield. To reduce the adverse effect of furfural on S. cerevisiae, exogenous ergosterol was supplemented and the impact on S. cerevisiae under furfural stress was studied. The lag phage was shortened by 50%, and the maximum ethanol yield was increased by 158% with 50 mg/L ergosterol supplementation under 4 g/L furfural stress. Flow cytometry analysis results showed that permeable cells and intracellular reactive oxygen species were decreased by 45 and 53%, respectively with the addition of ergosterol under furfural stress. The fatty acid composition of S. cerevisiae was changed; the intracellular glycerol and ergosterol content was increased after ergosterol supplementation. The saturation of fatty acid was increased. Addition of ergosterol promoted cell growth by decreasing oxidative stress. Under 4 g/L furfural stress, the lag phage of S. cerevisiae BY4741 (erg3△) and S. cerevisiae BY4741 (erg5△) was longer than that of S. cerevisiae BY4741, and the maximum ethanol concentration was decreased
Dissolution and Reaction Catalysis Strategy Using Alkaline Solvent for Mild Fabrication of Chitin Composite Hydrogel for Dye Adsorption
No full textAs the most abundant natural amino polysaccharide, chitin remains among the least exploited polymers due to its poor solubility, which restricts its research and utilization. In this study, a new chitin composite hydrogel was prepared by a mild process at 25 °C within a short time. To enhance the adsorption capacity, sodium carboxymethyl cellulose and attapulgite were introduced into the structure of a hydrogel by chemical reaction and physical interaction, respectively. Alkaline solution was used as a solvent to dissolve chitin and used as a catalyst to accelerate the cross-linking reaction between chitin and sodium carboxymethyl cellulose. This solvent (8 wt% NaOH/6 wt% urea solution) has dual functions: to dissolve chitin and to accelerate the cross-linking reaction of chitin with carboxymethyl cellulose by epichlorohydrin. The cross-linking reaction occurred at room temperature (25 °C) within a short time (4 h). Fourier transform infrared spectroscopy (FTIR) indicated that chitin and sodium carboxymethyl cellulose has been successfully cross-linked. X-ray diffraction results showed that the cross-linked structure was amorphous and that attapulgite kept its crystal structure in the hydrogel. Scanning electron microscopy showed the coarse surface of composite hydrogel with attapulgite. The adsorption capacity for methylene blue reached 167 mg g-1.
Alternative Particleboards Based on Treated and Untreated Hay
No full textAgricultural resources have a great potential to be a supplement or replacement for wood, especially in countries lacking wood resources, or during times of economic turmoil of wood markets, for manufacturing panel products. Previous research has focused on various sources including wheat straw, rice straw, rapeseed, or oil palm stems, but so far hay was not considered. Hay consists of cut and dried grasses, legumes, or other herbaceous plants. It has similar structure to wheat straw with a typical waxy surface layer and poor bondability. Soaking in NaOH was employed to improve the bondability of used full-length hay, or hay particles for urea formaldehyde (UF) resin. A comparison of the physical and mechanical properties was assessed. The vertical density profile of hay panels made from treated hay reached smaller differences between surface and core density. Full-length hay panels reached the higher average values of the equilibrium moisture content (EMC), due to the structure. The bending properties of panels made of treated hay particles showed improvement, with modulus of rupture being 3.5 times higher, and modulus of elasticity 2.6 times higher than that of the untreated hay particles. Thickness swelling after 48 hours decreased for the NaOH-pretreated hay panels
Effect of Thermal Bridge in Light-Frame Wood Wall
No full textThe presence of thermal bridges in a wall increases local heat conduction of the building envelope, resulting in a decrease in the wall’s average thermal resistance. Simultaneously, the internal surface temperature of thermal bridge is lower than that of the surrounding areas and shows a tendency of condensation. Therefore, it is necessary to employ thermal bridges in the stage of construction design. In the research, a two-dimensional steady-state numerical simulation was performed targeting thermal bridges with light-frame wood wall. Meanwhile, the heat bridge effect was simulated under different circumstances by changing the types of insulation and cladding materials, the number of the studs, and the framing factor. The results showed that the linear heat transfer coefficient increased linearly as the studs and framing factor rose. After the test was validated, the relative error rate between the simulated correction coefficients and the experimentally derived correction coefficients was 11.4%, indicating that the correction coefficients can be simulated
Preparation, Properties, and Mechanism of Anionic and Cationic Cellulose Nanocrystals/Waterborne Polyurethane Composite Films
No full textThree kinds of cellulose nanocrystals (CNCs) were added into waterborne polyurethane (WPU) and nanocomposite films that were prepared by solution casting. The influence of different ionic function groups on microstructure and properties of composite films was investigated. Compared with sulfated CNCs (SCNCs) and TEMPO oxidized CNCs (TOCNCs), FE-SEM images showed that cationized CNCs (CaCNCs) had better dispersion in composite films. The thermal decomposition of these composite films was delayed by 15 °C compared with pure WPU film. The tensile strength and fracture work of CaCNC/WPU composite film increased by 11.9% and 8.4%, respectively. The light transmittance of CaCNC/WPU composite film was highest among the 3 composite films, but its oxygen permeability was the lowest. In sum, the composite film with CaCNCs had optimal strength, toughness, light transmittance, and oxygen barrier properties, which is consistent with good compatibility of the two components and densest structure observed in SEM. There may be an ionic attraction and hydrogen bonds of CaCNCs and WPU in the composite film. The composite films are expected to have applications in food packaging, furniture coatings, and biomedical fields