Research Articles

Cellulose foams are potential sustainable alternatives for packaging, thermal insulation, and acoustic applications due to their porous structure and renewable origin. Besides good mechanical properties and moisture control, antimicrobial performance is essential for applications involving contact with moisture and organic matter, such as food packaging and medical materials. This study investigates the antibacterial, antifungal, and soil biodegradation behavior of cellulose foams coated with a thin layer (approximately 5 g/m²) of xylan hemicellulose and its modified derivatives, including acetylated and AKD (alkylketene dimer) modified xylan. The results showed that foams treated with acetylated xylan exhibited the highest antibacterial activity, with about 58% inhibition of Bacillus sp species after 24 h at 27 °C. A slight antifungal effect was also observed, with delayed growth of Aspergillus and Penicillium species. Both coating composition and xylan modification significantly affected the degradation kinetics.

Surface roughness plays a critical role in determining the performance and quality of paper products; however, its accurate determination depends strongly on the geometry of the stylus used in contact profilometry. Herein, the effect of stylus-tip size on surface roughness characterization was evaluated along with the suitability of fractal dimension (FD) analysis as a supplementary metric. Styluses with tip radii ranging from 0.25 to 1.75 mm were examined, and a 0.5-mm stylus tip (0.5R) yielded the most stable and reliable surface roughness measurements under a constant contact force of 5 gf. Coating considerably reduced surface roughness fluctuations, with the roughness mean absolute deviation (RMAD) decreasing by 78%. A comparison between a 0.5R conical stylus and a pyramidal stylus showed strong agreement in the R_a and RMAD values, confirming that the conical design maintained minimal contact area. High-resolution profilometry (0.1-μm spacing distance and 200,000 data points per scan) enabled the computation of FD via power spectral density analysis. FD values approached 2 for coated paper, reflecting a transition from line-dominated to more areal surface structures. These findings indicate that stylus selection critically affects surface roughness characterizations and that FD serves as a useful complementary descriptor for surface roughness changes.

Mechanical, microstructural, and hygrothermal behaviours were studied for hybrid epoxy composites reinforced with Borassus flabellifer fruit fiber (BFF), snake grass fiber (SGF), and gum Arabic. Six composites were fabricated with varying BFF-SGF ratios while maintaining constant epoxy (60%) and gum Arabic (10%) content. The composites were evaluated for tensile, flexural, impact, hardness, interlaminar shear strength (ILSS), density, water absorption, thickness swelling, and microstructural morphology using scanning electron microscopy (SEM). Hybridization significantly improved the overall structural performance of the composites. Among all compositions, the C3 composite (15% BFF / 15% SGF / 10% gum Arabic) exhibited the highest tensile strength (72 MPa), flexural strength (89 MPa), impact strength (28 kJ/m²), hardness (79 Shore D), ILSS (42 MPa), and density (1.21 g/cm³), and the lowest water absorption (6.1%) and minimum thickness swelling (1.53%) after 72 h. SEM analysis revealed improved fiber-matrix interfacial bonding, reduced void content, and uniform gum dispersion in the hybrid composites, which contributed to their superior performance. In contrast, single-fiber and gum-free composites demonstrated lower mechanical and hygrothermal performance due to weaker interfacial adhesion and non-uniform stress transfer. These findings indicate that BFF-SGF hybrid composites are promising materials for lightweight structural and semi-structural applications.

The goal of this project was to examine the bamboo craft activities at Sentra Industri’s “Bambu Kencana” center and to suggest technological know-how for creating composite bamboo panels. The employees of the Mechanical Engineering Department at the Faculty of Engineering at Universitas Muhammadiyah Yogyakarta (UMY) Indonesia got the opportunity to visit the center in order to carry this out. Wulung (Gigantochloa atroviolacea), apus (Gigantochloa apus), petung (Dendrocalamus asper), ampel (Bambusa vulgaris ssp.), and tutul (Bambusa maculata) were among the species found on the bamboo plantation at Jangkang Kidul, Sentolo. Apus is the species utilized for webbing. Day beds, chairs, and sofa settees are the center’s primary focus. The entire production process is based only on the old-fashioned way of nailing and tying rattan furniture. A bamboo composite panel is manufactured and brought to the center. The Purwanto people in Jangkang Kidul, Sentolo, received instruction on how to make a bamboo composite. In an attempt to revive the bamboo craft activity, UMY created a prototype using the bamboo composite. By giving a discussion on the process of creating a bamboo composite, the community was introduced to a value-added technology.

Effects of deep eutectic solvents (DES) type and pretreatment time were evaluated relative to lignin extraction efficiency. Three major indicators, including lignin yield, solid residue proportion, and lignin purity, were investigated in detail at fixed molar ratios (1:8 and 1:8:1) and temperature (120 °C). The lignin yield gradually increased over 2 to 10 h, reaching 78.9% at 6 h in the choline chloride (ChCl)-formic acid (Fa)-oxalic acid (OA) system. The solid residue proportion continuously decreased to 36.4%, while maintaining lignin purity above 90% without significant variation. According to the lignin structure analysis, the basic aromatic structure of lignin, comprising syringyl (S) and guaiacyl (G) units, remained unchanged after treatment with the ternary DES system. The C/O ratio of carbon-rich macromolecular structures gradually increased with reaction time, and the carbon content of the samples exceeded 60%. This study provides a new approach to optimizing lignin extraction.

Rice husk (RH) is a global agricultural byproduct that poses environmental challenges due to disposal via open burning. This study contributes new findings on the RH valorization from Roban, Sarawak, establishing a highly effective hydrochloric acid (HCl) leaching protocol that yields amorphous silica with enhanced purity. The scientific significance lies in the successful optimization of treatment parameters to achieve superior silica oxide (SiO₂) purity of 97.26 wt%, and significantly enhanced whiteness index (WI) (74.4), demonstrating the efficiency of this protocol for regional variants. Furthermore, the structural analysis demonstrates the isolation of a predominantly amorphous phase, providing a critical baseline for utilizing Sarawak-specific agricultural waste in high-performance industrial applications. Energy dispersive X-ray (EDX) spectroscopy analysis confirmed the successful elimination of metallic impurities (P, K, Ca, and Fe), resulting in a reduced mass yield from 43.18% to 36.64%. Furthermore, HCl treatment narrowed the particle size distribution (SPAN: 1.66) and slightly reduced the mean diameter to 33.0 µm. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses confirmed that both samples retained a stable amorphous structure. These results demonstrate that RH from this region is a viable, low-cost precursor for high-quality silica production, offering a sustainable alternative for agricultural waste management.

Leptoglossus occidentalis (Hemiptera: Coreidae), an invasive pest native to North America, causes significant damage to coniferous seed production worldwide. This study evaluated the effectiveness of contact spray and Arborjet trunk injection methods for controlling L. occidentalis in black pine (Pinus nigra) seed orchards in Bursa-Karacabey, Türkiye. Abamectin (18 g/L), as insecticide, was applied to plots of 50 trees each in 2025, and 300 cones were harvested in November 2025 for seed fill and empty cone analysis. Statistical analyses included Kruskal-Wallis and Wilcoxon tests with Bonferroni correction. Seed fill percentages were 9.7% (control), 33.9% (spray), and 52.8% (Arborjet trunk injection). The Arborjet method yielded approximately 5.6 times higher seed fill than the control with the lowest coefficient of variation (17.2%). Empty cone ratios differed significantly among groups (Fisher’s exact test, P < 0.001), with 0% in the Arborjet group versus 12% in the spray group. Treatment type explained 63.3% of total variance (η² = 0.633), with very large pairwise effect sizes (Cohen’s d = 1.33 to 3.42). These results demonstrate that systemic trunk injection should be prioritized over contact spray in seed orchards and gene conservation areas.

Glued laminated timber beams are vulnerable to brittle tensile failure in the tension zone, which limits their flexural efficiency and application in modern timber structures. This study investigated two reinforcement strategies for such beams: external steel reinforcement and bottom steel plate reinforcement connected with self-tapping screws. Unreinforced beams were tested as controls. Full-scale four-point bending tests were conducted to evaluate failure mode, load-deflection response, load-strain behaviour, bearing capacity, stiffness, and ductility. A three-dimensional finite element model was then developed and validated against the experimental results. The control beams failed in brittle tension, with an average ultimate load of 21.6 kN. The externally reinforced beams showed no effective improvement in flexural behaviour because prestress transfer and steel-timber interaction were insufficient. In contrast, the steel plate reinforcement restored 76% of the original load-bearing capacity of damaged beams and improved deformation capacity, although failure was still governed by timber delamination and screw shear. The validated numerical model reproduced the full loading-to-failure process and can support the design and optimization of reinforced timber members.

Sorghum bicolor is a promising multi-purpose crop for the bioeconomy. To unfold its potential, genotypes must be matched to the respective industrial processes. Five sorghum genotypes were evaluated under contrasting field conditions in Southwest Germany, focusing on the stalk as a source of lignocellulosic biomass for paper production. Dual-purpose hybrids, particularly Ganymed and Tarzan, demonstrated high resilience, maintaining stable biomass and sugar yield under drought stress. Compositional analysis of the stalk showed substantial genotypic differences in extractive, carbohydrate, and lignin contents. Ganymed and Tarzan possessed higher glucose and xylose levels and lower extractives than KIT1 and Hannibal, making them more favorable candidates for biobased processing. Soda pulping results aligned with chemical profiles: Ganymed achieved the highest pulp yield (50.2%) and moderate kappa number (30.5), while KIT1 showed the lowest yield (38.0%) and the highest kappa number (40.3), Tarzan and Zerberus produced pulps with low kappa values (23.5 and 19.8 respectively) but moderately reduced yields due to hemicellulose loss (43.9% and 39.9%, respectively). Paper produced from Tarzan (6.6 mN.m²/g) had high tear indices compared to the other sorghum genotypes. Overall, Ganymed, Tarzan, and Zerberus showed strong suitability as lignocellulosic feedstocks, offering promising options for biorefinery and paper production.

In response to the growing demand for smart household products, this study focused on the intelligent design optimization of a wooden dressing mirror that integrates traditional wood craftsmanship with smart home technologies. A data-driven design framework was developed by combining the PESTEL model, Kano demand analysis, and the Function-Behavior-Structure (FBS) model to address the personalized requirements of young single adults. PESTEL analysis identified market opportunities in sustainable wooden products and digital home integration, while the Kano model quantified and categorized user demands. The FBS model then transferred these demands into functional attributes, forming a comprehensive demand–function mapping framework. An empirical study with 16 young single adults employed semi-structured interviews and questionnaires. The results showed that (1) the Kano questionnaire had high reliability and validity (KMO > 0.92, Bartlett’s p < 0.001, Cronbach’s α > 0.92); (2) seventeen needs were classified as Must-be, One-dimensional, Attractive, and Indifferent, with “virtual fitting” showing the highest satisfaction sensitivity (0.734), and (3) the FBS model effectively guided the functional translation into hardware and software. The proposed PESTEL–Kano–FBS framework provides a practical approach for developing sustainable, user-centered smart wooden household products.