Volume 19 Issue 3

The mechanical performance of timber composite floors is influenced by the degree of composite action between the components. In this study, the shear strength performance of cross-laminated timber and glued laminated timber composite floors based on the joining method was evaluated by push-out test. Eight types of timber-timber composite joints were evaluated using three different methods: lag screw joints, glued-in rod joints using fully threaded bolts and glass fiber reinforced plastic, and hybrid joints. Strength characteristics were derived to make theoretical predictions on the load-carrying capacity of the joints. The results showed that the glued-in rod joints were superior to the lag screw joints, with slip coefficients and ductility measured as 10 times and 2.5 times higher, respectively. The reliability of the strength characteristics of the glued-in rod joints was remarkably different depending on the presence or absence of anti-adhesive tape applied to the timber-to-timber joint surface. The load capacity of the hybrid joint, which combines mechanical and glued-in rod joining methods, was 47% higher than that of the lag screw joint and 38% higher than that of the glued-in bolt joint. In the European Yield Model modified to estimate the load capacity of joints, the rope effect and the yield moment of the fasteners had a remarkable impact on the predicted load capacity.

A pre-treatment process was evaluated in this work for wastewater from paper recycling using microwave technology followed by rapid precipitation of contaminants through centrifugation. Artificial neural networks (ANNs) were used to analyze and optimize the turbidity values. Thirty experimental runs were utilized including microwave (MW) power, duration, centrifuge time, and centrifuge speed as input variables, generated by the Central Composite Full Design (CCFD) approach. The experimental turbidity ranged from 8.1 to 19.7 NTU, while predicted values ranged from 8.4 to 19.7 NTU by ANN. The ANN model showed a robust prediction performance with low mean squared error values during training and testing. Moreover, high R² values showed a remarkable agreement between the experimental observations and ANN predictions. The results obtained from the input values (A:150.00, B:60.00, C:15.00, D:30.00) of sample 2, which gave the lowest turbidity value, showed the most removal of pollution. The results obtained from the input values (A:250.00, B:60.00, C:7.00, D:20.00) of sample 30, which gave the highest turbidity value, showed the least removal of pollution. The results showed that increasing RPM and time of the centrifugation process significantly affected the removal of pollution in wastewater.

The structure of vascular bundles and the mechanical properties of fibers are crucial factors determining the utilization of bamboo. This study investigated the structure of vascular bundles and evaluated the morphological and micromechanical properties of the fibers in Oligostachyum sulcatum. The results showed that the fiber length and width of O. sulcatum meet the requirements of raw materials for the papermaking process. However, the fiber content in O. sulcatum is relatively low, which may increase the cost of papermaking. The vascular bundle growth exhibited non-uniformity, especially at the top part, with no discernible pattern in bundle area changes. The nanoindentation testing demonstrated that the bamboo’s indentation modulus of elasticity (IMOE) and hardness values were comparable to those of moso bamboo (Phyllostachys edulis), suggesting its potential as a substitute in engineering applications.

Biosynthesis of metal nanoparticles is a cost-effective and environmentally friendly technology. In the present study, copper nanoparticles (CuNPs) were synthesized using white tea leaf extracts. They were then characterized for their chemical structure and evaluated ability for the methylene blue (MB) degradation in the adsorption system with H₂O₂. XRD and FTIR analyses revealed that the CuNPs were present as an amorphous phase, with the O-H polyphenol compound bound to the Cu ion. The XPS deconvolution indicated the presence of Cu²⁺ and Cu⁺ in the CuNPs. TEM images revealed that the average particle size was less than 10 nm. The CuNPs synthesized using different precursors exhibited effective ability for the MB degradation in the adsorption system. Based on the adsorption theory, the pseudo-second-order model fitted well with the experimental data, and the thermodynamic calculation suggested that the reaction was endothermic, and spontaneous. The CuNPs synthesized using the CuSO₄ precursor exhibited higher antibacterial activity compared to those synthesized using Cu(NO₃)₂. In conclusion, white tea leaf extract is an inexpensive and easily available precursor for the biosynthesis of copper nanoparticles. Further analysis based on an assumed degradation work will be considered in future work.

The fabrication of charcoal briquettes was considered using two distinct bases: palmyra palm and oil palm shells. The critical role of binders – namely tapioca starch, molasses, and termite mound clay (TMC) – were emphasized in influencing the properties of the briquettes. ANOVA results revealed that both the type of binder and charcoal significantly impacted various characteristics, such as proximate components like volatile matter content, and physical properties including combustion time. Briquettes made from palmyra palm shells notably demonstrated superior performance in terms of combustion time and onset time of saturation (OTS). Among the binders, tapioca starch was distinguished for contributing to the lowest ash content and the highest fixed carbon in the briquettes. Conversely, briquettes bound with TMC, despite having the lowest volatile matter percentage, also exhibited the highest ash content and fragility, in addition to the shortest combustion time. These findings highlight the importance of selecting appropriate binders to enhance the efficiency and sustainability of charcoal briquettes, aligning with the increasing demand for environmentally conscious energy solutions in the face of escalating global energy needs.

All-cellulose composites (ACCs) have been fabricated by using a variety of cellulosic sources, versatile technologies, and are sustainable alternatives for traditional composites. In this study, nonwoven-woven ACC laminates were created from wood-based Spinnova short fibers and Lyocell fabrics via partial dissolution and an NaOH-urea solvent system. The less-known wood-based Spinnova fiber is created for the textile industry, but it also has great potential for the composite industry. To identify the mechanical properties of ACCs—which greatly influence the range of material application—tensile, impact, and flexural tests were conducted. The mechanical properties indicated only moderate properties, which are influenced by high porosity and weak fiber bonding. Despite this, valuable information on the nonwoven-woven structured ACCs was obtained. To improve the ACC laminate’s ability to resist moisture, bio-based coatings (e.g., commercially available birch bark betulin and suberin acid mixture) were applied on the surface of ACCs and it successfully improved the wetting resistance. The results of contact angle analyses demonstrated that the highest contact angle of 128° was measured for betulin-coated laminates and the best stable hydrophobicity calculated a minute after the beginning of the experiment were observed at 109° for the uncommercial pressurized hot ethanol (PHE) extract of birch bark.

Static life cycle assessment (LCA) methodologies fail to consider the temporal profiles of system inputs and outputs (including emission timing), such that they underestimate the benefits of temporarily stored biogenic carbon in bioproducts, such as cotton. This research focuses on greenhouse gas emission timing and applies dynamic emission accounting to the life cycle of cotton woven pants. The significance of temporary biogenic carbon storage and emission timing is illustrated by converting the 2017 Cotton Incorporated static LCA to a dynamic model using the Dynamic Carbon Footprinter (baseline scenario). A reduction in cumulative radiative forcing for dynamic relative to static modeling of 22%, 5%, and 2% are observed at 10-years, 30-years, and 100-years, respectively. Alternative scenarios analyzed include converting cotton woven pants at end of life to bioenergy, to compost, or to building insulation, an alternative cotton production scenario using regenerative agricultural practices, and two pants extended lifetime scenarios. The regenerative agricultural practice scenario provides reductions in cumulative impacts compared to the baseline scenario of 96%, 69%, and 105% after 10, 30, and 100-years, respectively. A 3x extension in the lifetime of pants provides a benefit in reduced cumulative impacts of 31%, 40%, and 41%, after 10, 30, and 100-years, respectively. This case study with cotton demonstrates that dynamic LCA is a useful tool for assessing the benefits of biobased products, and it allows for more nuanced analysis of reductions in climate impacts in both the short- and long-term time horizons.

γ-Valerolactone (GVL) is a promising biomass-based platform compound that can be used for the removal of hemicellulose in pulp. In this study, a paper-grade pulp was treated using GVL to generate dissolving pulp for viscose production. The GVL concentration, treatment temperature, and reaction time had significant effect on the hemicellulose dissolution. The dissolving pulp with α-cellulose content of 92.3% and hemicellulose content of 5.45% was achieved with 60% GVL at 120 °C for 2 h. The Fock reactivity and intrinsic viscosity of the obtained dissolving pulp were 54.6% and 595 mL/g, which is comparable with the commercial product. In addition, GVL spent liquor was also recycled and reused to upgrade paper-grade pulp. By using purified recycled GVL to treat original pulp, the Fock reactivity of pulp was improved, and the cellulose content of as-prepared upgraded pulp increased to 92.1%, which was close to the cellulose content of dissolving pulp obtained from fresh GVL solution, while the intrinsic viscosity decreased significantly to 598 mL/g. Therefore, the efficient reuse of GVL not only ensured the high quality of dissolving pulp, but it also saved production costs and reduced environmental pollution.

In recent years, the custom wardrobe market has been steadily developing. While meeting the functional needs of users, it is gradually shifting towards aesthetic preferences. Rapidly grasping users’ preferences for the appearance of custom wardrobes is a key focus of current research. This study collected a large number of decorative surface images of custom wardrobes and objectively analyzed the design features based on color moments and Tamura texture feature data in computer image analysis methods. K-means cluster analysis was performed on the feature data. Collected images of the points closest to the cluster centers were further screened to select representative finish images, and finally a questionnaire survey was conducted at Nanjing Forestry University, with the help of semantic differential method and factor analysis. The characteristics of the samples were comprehensively summarized to infer design elements. The study found that warm-toned, medium-low saturation, and medium brightness surfaces were preferred by the panel. Different colors, contrasts, saturations, brightness, element features, and arrangements have significantly different effects on visual perception. These conclusions can provide a reference for subsequent custom wardrobe design.

Bark, the outermost tissue, plays an important role in protecting trees from damage induced by living organisms and the surrounding environment. Bark differs from the xylem primarily by the presence of suberin in cork cell walls. However, few studies have examined the role of suberin and its interactions with other chemical components in the cork. Consequently, this study aimed to understand the distribution of chemical components, including suberin and lignin, and their respective roles in cork cell walls, using Cerasus jamasakura (Siebold ex Koidz.) H. Ohba. Suberin and lignin were gradually and selectively removed from thin strip specimens. Fourier transform infrared (FTIR) spectroscopy suggested that desuberinization removed both suberin and part of the other matrix substances within a few minutes of treatment, whereas delignification exclusively removed lignin. Further microscopic observation revealed that suberin present was mainly in the secondary wall of cork cells, whereas lignin was present in both the tertiary wall and compound middle lamella. In addition, the cell wall collapse of the cork was only found in desuberinized specimens, whereas delignified specimens only showed monotonic contraction. Taken together, these results suggest that the presence of suberin in the cork contributes to the shape stability of cork cell walls.