Volume 19 Issue 3

The use of wood in the construction sector to reduce greenhouse gas (GHG) emissions is garnering global interest. In South Korea, the wood usage in public buildings is limited, being influenced by factors such as the high price of wood products and their limited use in large structures. In this work the future wood consumption in South Korea is predicted based on its potential use in current public buildings. The structural wood products required for the buildings were quantified based on the available statistical data. Items investigated were the (1) number of buildings started, (2) ratio of public buildings, (3) ratio of wooden structures, (4) average floor area of wooden buildings, (5) material cost per floor, and (6) wood prices. Assuming that the buildings contain reinforced-concrete and wooden structures, the wood consumption was estimated based on the replacement ratio. The results indicated that the prices of wood products were relatively higher than those of raw timber. The number of buildings is expected to decrease in line with the expected population decline, resulting in the decrease of wood amount required for public buildings. To achieve long-term GHG-reduction goals, it is important to replace the existing public buildings in Korea with wooden structures.

The mortise and loose tenon (M&LT) joint is a form between mortise-and-tenon (M&T) joint and dowel. It combines the advantages of easy processing and high bonding strength and has no requirement for the shape of the tenon shoulder. However, there is a lack of research conducted separately on the parallel-to-grain part of M&LT joint. This study explored the withdrawal capacity of the equivalence I-type specimen to focus on the strength of the parallel-to-grain part of M&LT joint by conducting mechanical experiments and establishing finite element model. The results indicated that (1) The largest average pull-out load occurred at the group of 0.1 mm interference fit with the value of 16000 N, most of the joints underwent shear damage of material parallel-to-grain; (2) The maximum load of FEM is 14300 N with an error of 10.5%, so finite element model is a rational approach to predict the withdrawal strength of parallel-to-grain connection of M&LT joint.

This paper reports the first study of phyco-remediation of cyantraniliprole, a second-generation diamide insecticide with high toxicity and persistence in aquatic environments, using the green microalga Chlamydomonas reinhardtii. Cultures of C. reinhardtii were treated with four concentrations of cyantraniliprole (0, 25, 50, and 100 ppm). The removal efficiency, antioxidant responses, and biomass composition of the microalga were measured after 1 h and one week of exposures. C. reinhardtii was able to remove cyantraniliprole from the medium by biodegradation, biotransformation, bioaccumulation, and bio-adsorption mechanisms, achieving up to 87.0% removal within 1 h and 84.5% after one week. The microalga also maintained acceptable levels of enzymatic and non-enzymatic antioxidants, indicating its tolerance to cyantraniliprole stress. Moreover, some treated cultures (especially those with 25 and 50 ppm cyantraniliprole) showed enhanced specific growth rate, and biomass productivity compared to control cultures. In addition, those with 50 and 100 ppm cyantraniliprole showed enhanced carbohydrate and lipid concentrations compared to the control cultures. These results suggest that C. reinhardtii is a promising candidate for bioremediation of cyantraniliprole-contaminated water and biofuel production.

Green routes for the bio-designing of bicomponent nanocomposites and their utilizations have attracted many investigators. Bio-designing of CuO@ZnO nanocomposites was performed using spent mushroom substrate (SMS). Ultraviolet-spectrophotometry, transmission electron microscopy, Fourier transform infrared (FT-IR), and energy dispersive X-ray (EDX), besides X-ray diffraction (XRD) were exploited to characterize the synthesized CuO@ZnO. The dimensions of CuO@ZnO nanocomposites ranged from 31.4 and 95.9 nm. Both FT-IR and EDX analyses displayed the presence of some organic constituents from the SMS that joined to the surface of the fabricated CuO@ZnO nanocomposite. CuO@ZnO nanocomposite succeeded in inhibiting Candida albicans with an inhibition zone of 33.5 ± 2 mm. C. albicans biofilm was affected by CuO@ZnO nanocomposite with biofilm inhibition of 25.08, 68.70, and 88.56% at 25, 50, and 75% of minimum inhibitory concentration, respectively. Molecular docking studies showed substantial binding affinities, as well as common hydrogen bonds. Optimum binding sites for CuO and ZnO nanoparticles were found to have binding affinities of interactions with 4YDE, 3DRA, and 1EAG proteins of C. albicans, resulting in, respectively, -2.7942, -3.30097, and -2.52129 kcal/mol, and -3.78244, -4.6029, and -4.1352 kcal/mol values. The findings suggest that CuO@ZnO nanocomposite can effectively suppress C. albicans growth.

Catastrophe theory was used to establish a safety assessment model to reduce the reliance on subjective judgments in evaluation of timber-framed heritage buildings. This study was conducted in three phases. Initially, a comprehensive evaluation index system was established from the perspective of foundation. It consisted of eight aspects and 25 safety evaluation indicators using superstructure load-bearing elements, maintenance structures, and their interconnections in timber-framed heritage buildings. The 25 safety evaluation indicators included foundation, base, stone piers, columns, beams, lintels (beams, pads, and other bending components), bracket sets, arches, maintenance walls, beam-brace connections, and roof structures. The bottom-level indicators in the index system were dimensionless. The second phase employed typical catastrophe models (cusp, swallowtail, and butterfly) for normalization, resulting in calculated catastrophe scales and evaluation levels. The case study of the Buddha Hall of Zhihua Temple, Beijing, was applied in the final phase. It was found that the catastrophe scales method solved the subjectivity issues in determining weights. Additionally, the calculations were found to be concise and reliable, providing accurate results. The model can be used as a theoretical reference for the future safety assessment of timber-framed heritage buildings.

The unit density value is a key quality index for pellet feed production. This study presents an experimental evaluation of the unit density for the pelletizing of caragana and corn straw, under different levels of technological parameters, including moisture content, weight ratio of caragana, and particle size. Results showed that these three parameters of raw materials affected unit density. Through orthogonal test and extreme variance analysis, it was shown that the various moisture content and weight ratio of caragana had a significant effect on the density of pellets, and the influencing factors were ranked as moisture content > weight ratio of caragana > particle size of the materials. In compliance with industry standards, optimizations of the parameters resulted in a granulation density of 1.15 g/cm³ with particle size of 5 mm, moisture content of 13.4% and weight ratio of caragana of 24.8%.

In this research, a novel mineral-based composite board was developed using gypsum as a mineral binder and rice straw as a readily available agro-based resource. The study involved two key phases: Phase 1: The preliminary assessment of rice straw-gypsum composite involved integrating different ratios of rice straw into gypsum to examine the influence of rice straw integration on the composite board’s performance. The specific proportions used were 90:10%, 80:20%, and 70:30% for rice straw to gypsum. Phase 2: Reinforcement with bacterial nanocellulose fibers. In the subsequent phase, gypsum board composites containing 10%, 20%, and 30% rice straw were further enhanced by the addition of bacterial nanocellulose fibers at 1% and 3% levels. The results indicated a significant influence of rice straw incorporation on the physical and mechanical properties of the panels. The composite boards with 3% bacterial nanocellulose fiber gel exhibited the highest mechanical performance, with values of 13.5 MPa for modulus of rupture, 4650 MPa for modulus of elasticity, and 0.79 MPa for Internal Bond. The study revealed that the adverse effects of rice straw substitution on the mechanical properties and thickness swelling of the panels could be mitigated to a certain extent by incorporating nanocellulose fibers.

To guarantee the uniformity of the flow field within an equilibration chamber during the process of hot air baking and to elevate the quality of high-density wood panels, an in-depth analysis was conducted, focusing on the impact of various factors such as the number of side air inlets in the chamber, the spacing between panel gaps, and the configuration of the bottom air inlet spacing. The aim was to optimize the structural parameters to enhance the uniformity of temperature and wind speed. The results indicated that the factors influencing the flow field uniformity within the equilibration chamber were, in descending order of importance, the number of side inlets, the spacing between the bottom inlets, and the distance between the plate gaps. In addition, the optimized hot air increased the average velocity by 0.16 m/s and the average temperature by 6.44K. The percentage of boards passing the inspection of its substandard products was only 9.2%, an improvement of 11.8 percentage points, and the average moisture content was also reduced to 8.76%. The simulation and analysis program effectively improved the uniform distribution of temperature and air velocity in the equilibration chamber and improved the quality of panel production. Therefore, the adoption of this solution helps to achieve efficient drying of wood-based panels and reduce costs.

The production of cashew nuts has been increasing globally, leading to a greater volume of waste materials that require proper management. Nevertheless, cashew nutshells (CNS), currently considered waste by most processors, offer a noteworthy opportunity for alternative applications owing to their distinct physical, chemical, and thermal properties.  This article reviews alternative applications for CNS that can leverage these properties, while evaluating research gaps. The potential uses are classified into three categories: material development, energy production, and substance absorption. In the materials segment, various examples are discussed where CNS serves as raw material to synthesize biopolymers, cementitious materials, and a broad range of composites. The energy production section discusses various processes that utilize CNS, including pyrolysis, gasification, and briquette production. The absorption section presents CNS and activated carbon derived from CNS as effective absorbents for liquid-phase and gas-phase applications. While this review highlights numerous research-level possibilities for CNS utilization, only a few of these options have been implemented within the industry. Consequently, further research is essential, particularly in CNS characterization, economic and environmental assessment, and real-life implementation, to broaden and enhance the integration of this biomass into applications that can contribute to the value of both its production and processing chain.

The potential of paper and paperboard as fiber-based materials capable of replacing conventional polymer-based materials has been widely investigated and evaluated. Due to paper’s limited extensibility and inherent heterogeneity, local structural variations lead to unpredictable local mechanical behavior and instability during processing, such as mechanical forming. To gain a deeper understanding of the impact of mechanical behavior and heterogeneity on the paper forming process, the Finite Element Method (FEM) coupled with continuum modeling is being explored as a potential approach to enhance comprehension. To achieve this goal, utilizing experimentally derived material parameters alongside stochastic finite element methods allows for more precise modeling of material behavior, considering the local material properties. This work first introduces the approach of modeling heterogeneity or local material structure within continuum models, such as the Stochastic Finite Element Method (SFEM). A fundamental challenge lies in accurately measuring these local material properties. Experimental investigations are being conducted to numerically simulate mechanical behavior. An overview is provided of experimental methods for material characterization, as found in literature, with a specific focus on measuring local mechanical material structure. By doing so, it enables the characterization of the global material structure and mechanical behavior of paper and paperboard.