Volume 18 Issue 3

Microcrystalline cellulose (MCC) is a green material that has widespread applications in pharmaceuticals, food, cosmetics, and other industries because of its biocompatibility, biodegradability, hydrophilicity, and acid-insolubility. In this study, MCC was prepared from cotton waste via alkaline treatment and sulfuric acid hydrolysis. Further, the synthesized cotton-based MCC was characterized using Fourier transform infrared (FTIR), X-ray photoelectron, and energy dispersive X-ray spectroscopies. Based on these results, the major components were identified as carbon and oxygen. This finding was evidenced by the FTIR analysis, which displayed peak wavenumbers at 3446.9, 2891.1, 1649.5, 1380.1, 1061.2, and 1050 to 1150 cm^-1. The surface morphology was also examined by field emission scanning electron microscopy and field emission transmission electron microscopy, which showed that the prepared MCC has a smooth surface and a consistent, rod-like shape. In addition, the MCC exhibited the typical diffraction peaks of a crystalline structure of cellulose II at 12.2°, 20°, and 22.03°, which correspond to the diffraction planes of 1-10, 110, and 020, respectively, and had a crystallinity index of 78.7%. Moreover, the prepared MCC had a diameter of 37.8 µm and exhibited good stability with a peak at -76.5 mV. Further, the cotton-based MCC exhibited high thermal stability, as revealed by the TGA.

The pyrolysis of corn stalk (CS) was carried out to investigate the effect of wet torrefaction (WT) pre-treatment and Zn/Ni-HZSM-5 on the production of bio-oil characteristics. The synergy between WT and the loaded metal catalyst was also analyzed. The oxygen content of the CS was reduced from 50.5% to 40.8% with WT, and hemicellulose was almost removed. WT pretreatment also significantly reduced the oxygenated compounds of bio-oil and increased the selectivity of phenols, aromatics, and anhydro-sugars. The addition of catalyst improved the deoxygenation, oligomerization, and aromatization during pyrolysis. The loading of Zn and Ni could optimize the pyrolysis reaction path and increased the relative content of monocyclic aromatics (MAHs) from 3.58% to 9.67% and 6.44% during the pyrolysis of CS-WT, respectively, and bimetallic catalyst further enhanced the relative content of MAHs to 11.1%. The relative content of aromatics below C9 was higher than other groups (14.8%). Thus, the WT pretreatment of raw materials and synergistic effect of catalysts can jointly optimize the biomass pyrolysis reaction.

Natural dyes are widely available and mainly extracted from natural plants with green, safe, and sustainable characteristics. This study used Cinnamomum camphora fruit peel as the raw material under the premise of minimizing chemical reagents and employed the microwave-extraction method to extract the dyes from C. camphora fruit peel. The dye extraction conditions were optimized using response surface software via the Box-Behnken model to formulate a response surface test protocol. The results showed that optimizing the experimental conditions by the response surface method was reliable. The optimal extraction condition was found to be material-liquid ratio 1:20 (g: mL), microwave time 90 s, and microwave power 420 W. It is of practical application value to improve the extraction quantity of C. camphora fruit dye. At the same time, the infrared spectrum and HPLC-MS analysis of Cinnamomum camphora fruit dye were analyzed, and the stability of the dye was tested.

The preparation of bio-butanol from corn starch requires saccharification and fermentation processes. In view of the fact that the pH value at the later stage of fermentation is applicable to the enzymatic hydrolysis of glucoamylase, the effects of simultaneous saccharification and fermentation (SSF) and separate hydrolysis and fermentation (SHF) were compared in this paper. 11.2 g/L butanol and 21.5 g/L total solvent could be obtained by the SSF process, while the yield was 9.74 g/L butanol and 17.2 g/L total solvent in the SHF process. The SSF process required a shorter overall process time (120 h) than the SHF process (144 h) and resulted in a large increase of 38.9% in butanol productivity (2.25 g/Ld for SSF compared to 1.62 g/Ld for SHF). These results show that the application of SSF can reduce the fermentation overall time, simplify the fermentation process, and reduce equipment investment and operating costs.

Lignin structure is known to have significant effects on the enzymatic hydrolysis efficiency (EHE) of lignocellulose. In this study, the lignin produced from corn stalk pretreated with p-toluenesulfonic acid (PCS) was used to prepare carboxylated and quaternized lignin (CQCL) and epoxidized lignin (ECL), and the effect of the two modified lignin forms on the EHE of PCS was investigated. The results showed that EHE after adding CQCL (83.7%) was higher than adding ECL (60.8%). To explore the reasons, the unproductive adsorption, cellulase-lignin interaction, and molecular dynamics experiments were conducted. The results showed that the smaller hydrophobic interaction and electrostatic attraction between CQCL and cellulase caused less unproductive adsorption between CQCL and cellulase than ECL. Additionally, CQCL and ECL changed differently the conformations of key amino acid residues of cellobiohydrolase I and endoglucanase II, which was also responsible for the higher EHE after adding CQCL.

Chinese traditional colors are an important component of traditional culture, containing profound national culture and unique aesthetic ideas. Analyzing and applying the color characteristics of traditional Chinese colors can integrate traditional color design concepts into contemporary design, implying a design path from tradition to the present, and meeting the diversified and personalized consumer needs of the market. This study examined consumers’ psychological perception of traditional colors using the Natural Color System and Likert scale. Factor analysis and association tests revealed color attributes and image cognitive traits. The results reveal that blackness often degrades color image judgement. Saturation influenced Tang and Qing color perception. Red, green, and blue are the ideal hues for the Tang, Song, and Qing Dynasties, respectively. Song Dynasty culture and emotions are perfectly reflected in the green color. The Ming Dynasty’s visual traits are blue, and its culture and feeling are yellow. The red color best reflects the Qing Dynasty’s cultural and emotional traits, and the blue hue best matches its aesthetic traits. The study attempts to quantify customised furniture color design and improve product color design’s cultural meaning and aesthetic effect.

Knot detection is an important aspect of timber grading. Reducing the false-positive frequency of knot detection will improve the accuracy of the predicted grade, as well as the utilization of the graded timber. In this study, a framework for timber knot detection was proposed. Faster R-CNN, a state-of-the-art defect identification algorithm, was first employed to detect timber knots because of its high true-positive frequency. Then, an overlapping bounding box filter was proposed to lower the false positive frequency achieved by Faster R-CNN, where a single knot is sometimes marked several times. The filter merges the overlapping bounding boxes for one actual knot into one box and ensures that each knot is marked only once. The main advantage of this framework is that it reduces the false positive frequency with a small computational cost and a small impact on the true positive frequency. The experimental results showed that the detection precision improved from 90.9% to 97.5% by filtering the overlapping bounding box. The framework proposed in this study is competitive and has potential applications for detecting timber knots for timber grading.

The essential oil industry is a growing sector that generates 5.41 billion USD annually worldwide. Essential oils are widely used in medicine, agriculture, and perfumery. Although there are available systems in the market for domestic essential oil extraction, replacing the entire equipment in case of repair or malfunction can be costly. To address this problem, a pilot-scale essential oil extractor system was developed that operates through hydrodistillation. This system was used to process various citrus wastes such as green and yellow lemons, oranges, grapefruits, and Eucalyptus globulus. A factorial design was performed, and the best conditions were used to extract other biomass residues. GC-MS analysis revealed that the primary compound for orange, grapefruit, and green lemon essential oils is D-imonene, with 95.4%, 95.5%, and 49.2%, respectively. For yellow lemon the primary compound appeared to be D-limonene with 73.0% content, though the GC/MS data were less clear, and for eucalyptus, it is eucalyptol with 71.0%. The estimated production costs were 0.01 USD/mL, 0.04 USD/mL, 0.06 USD/mL, 0.07 USD/mL, and 0.15 USD/mL for orange, grapefruit, green lemon, yellow lemon, and eucalyptus essential oils, respectively. Therefore, the developed system is a competitive option for pilot-scale essential oil extraction.

In response to the lack of accurate and reliable parameters in the discrete element simulation analysis of the sugarcane leaf crushing and return device, in this work, the actual and simulated errors of two stacking angles α and β of sugarcane leaves were used as indicators to calibrate the discrete element parameters. The second-order regression models between the important parameters and the indicators were obtained by Plackett-Burman test, steepest climb test, and Box-Behnken optimization test, and the analysis of variance and interaction factors were performed. The response surface method and particle swarm optimization algorithm were used to find the best significance parameters, and the best combination of significance parameters was obtained: the static friction coefficient between sugarcane leaves was 0.306, the rolling friction coefficient between sugarcane leaves was 0.198, and the recovery coefficient of sugarcane leaf-plate collision was 0.102. The relative errors of the simulation results and the physical test stacking angle α and stacking angle β were 0.609% and 1.643%, respectively. The calibration parameters can provide a theoretical reference for the design and research of sugarcane leaf crushing and returning machines, as well as the calibration of discrete element model parameters for leaf crops with high water content.

Properties of Sentang wood planted in Kelantan, Malaysia, were studied,  focusing on the effect of radial growth rate on variation in the fiber and vessel element dimensions, moisture content, density, shrinkage, bending, and compression strength at the breast height of the tree. The trees were categorized into slow-, average-, and fast-growth categories, based on their breast height diameter and standard deviation. The variations in properties were then examined from the pith to the bark. The fiber length and diameter tend to decrease until a certain distance from the pith, followed by an increase toward the bark. Contrastingly, the vessel element length and diameter tend to increase until a maximum size is reached and then exhibit a relatively constant size toward the bark. The fast-growing trees tended to have longer and larger fibers, while the slow-growing trees tended to have longer and larger vessel elements. In addition, the fast-growing trees tended to have a higher green moisture content and shrinkage, lower density, lower modulus of rupture (MOR), and lower compression strength. The results revealed that growth rate seems to influence the modulus of elasticity (MOE) less than the MOR and compression strength.