Volume 20 Issue 2

Nine-layer laminated veneer lumber (LVL) 1300 by 850 mm, in nominal thickness of 20 mm, was produced using beech veneer and reinforced LVL (RLVL), by inserting carbon fiber fabric between the veneer sheets. The research aimed to assess the enhancement of flexural properties, both in edgewise and flatwise bending, of beech LVL reinforced with carbon fiber fabric. Two types of reinforcements were made, using two types of adhesives: phenol-formaldehyde (PF) and polyurethane (PUR), in the industrial conditions. In the first group of samples (K1), the reinforcements were placed further from the neutral axis, and in the second group (K2) closer to the neutral axis. These groups were compared to the unreinforced control sample (K). Some physical properties, bending behavior parallel to the grain, and failure mode were determined and analyzed. Edgewise bending strength of the RLVL was about 11% higher than the control in the case of PF adhesive, while flatwise bending strength was about 40% lower than the control in the case of PUR adhesive. The experimental data were verified using the ANOVA model. The most important results of the study define different behavior and fracture mechanisms for each reinforcement and adhesive, highlighting the potential of RLVL for structural applications.

Potential global warming impact makes it important to study the morphological response of plants under stress conditions. The ability of trees to survive and adapt to possible scenarios can be understood in detail thanks to this awareness. This study investigated the variation in needle and cone morphology of black pine trees growing in different altitudes and aspects (slope surface) within the Western Black Sea region of Türkiye. The research material consisted of 1560 needle and 1560 cone samples from 78 destructively sampled adult black pines growing in six forest stands of varying altitude and aspect. Altitude and aspect were found to be significant in influencing all investigated morphological characteristics including needle length (nl), needle width (nw), needle thickness (nt), sheath length (sl), cone length (cl), cone width (cw), and cw/cl ratio. The most obvious variation between morphological features was found in the cw as a function of altitude, with cones becoming wider as altitude increased. In addition, the morphological diversity of needles and cones due to aspect effect is more common at lower altitudes where there is a greater water deficit. Morphological variation was found to be higher in south-facing slopes where water stress is higher.

To study the seismic performance of ancient timber structures with attached windows and masonry walls,  a low-cycle reciprocating load test was conducted on a 1:2 scaled model of the Kanchuang frame. The frame’s failure modes, hysteretic behavior, skeleton curves, stiffness degradation, and energy dissipation capacity of the frame were obtained. Test results showed that the masonry wall of the structure was the first to crack and fail. The tenons of the wood window pulled out of the mortises gradually while the loading displacement increased. In addition, finite element models of the Chinese traditional Kanchuang frame were established and analyzed. The test results were basically consistent with the finite element analysis results. Based on the finite element models, the influences of impact parameters including friction coefficient, elastic modulus, compressive strength in parallel-to-grain directions, and vertical loads on the seismic performance of the Kanchuang frame were analyzed. The results showed that the ultimate load-bearing capacity, initial stiffness, and energy dissipation capacity of the Kanchuang frame are increased with the increase of friction coefficient, compress strength, and the elastic modulus. The influence of elastic modulus in perpendicular-to-grain directions was minor. The initial stiffness and energy dissipation capacity of the structure increased while the vertical loads increased. However, the ultimate peak loads and stiffness decreased with the increase of the vertical loads.

The rapid growth in Malaysia’s oil palm industry has resulted in the increase in production of palm oil and oil palm waste such as palm kernel shell (PKS). However, the lack of awareness on the beneficial value of these wastes has led to sustainability issues. Thus, PKS can be converted into biochar (PKSB) and can be used as a potential bio-filler. The PKSB was produced in sizes ranging from micro to nano using a high energy ball mill (HEBM) to be used as a filler in natural rubber (NR) vulcanizates. This study evaluated the effects of varying n-PKSB loadings (0 to 10 phr) on the cure characteristics, bound rubber content (BRC), swelling, tensile, and abrasion properties of the NR vulcanizates. Results showed that n-PKSB-filled NR vulcanizates had lower minimum torque (M_L) and cure rate index (CRI), along with improved BRC and crosslink density as the filler concentrations increased. The optimum loading ratio was 5 phr (F4), as this formulation offered the best mechanical properties and more homogenous dispersion of n-PKSB compared to other loadings. The overall performance of F4 showed high crosslink density (7.82 x 10^-5 mol/cm³), BRC (3.94%), tensile strength (17 MPa), abrasion resistance (32.37%), and lower EB (451%). Overall, n-PKSB has great potential as bio-filler, addressing oil palm waste issues and benefiting the industry.

Poly(butylene succinate-co-terephthalate) (PBST)/ layered zirconium phosphate (ZrP) composite was prepared by melt blending. The dispersion and orientation of ZrP within the PBST matrix were subsequently modified using a stretching-lamination post-treatment process. Effects of filler content and stretching ratio on the microstructure, rheological properties, thermal properties, mechanical properties, and barrier performance of the composites were investigated. Results showed that after post treatment, sliding occurred between the layers of ZrP, enhancing its dispersion within the PBST matrix and aligning it along the direction of the applied force. Furthermore, the degree of orientation increased with higher stretching ratios. In the stretching ratio of 300%, the intensity ratio of the crystal plane characteristic peaks (I₍₀₀₂₎/I₍₁₀₀₎) for the composite increased from 3.48 to 7.86. When the ZrP content was 3 wt% and the stretching ratio was 300%, compared with composite without post stretching, its tensile strength and elongation at break improved 10.7% and 14.4%, respectively. This study presents a novel solution to the dispersion challenges of nanofillers in composites from the perspective of processing methods, while also offering a solid foundation for the subsequent incorporation of nanocellulose to develop bio-based composites with higher mechanical strength and barrier properties.

Using environmentally friendly additives has been considered widely in different industries, especially papermaking, which has a high dependency on additives. The current study focused on applying a plant-based gum obtained from Astragalus gossypinus (a well-known plant in some regions of the world, especially Iran) in the papermaking process. The gum characterization showed a high content (about 84%) of carbohydrates (mainly hemicellulose with xyloarabinan monomers in the main chain and about 8% of uronic acid in the side chains), low ash content (2.58%) and insignificant protein content. FTIR spectra confirmed the structural results. The weight average molecular weight (M_w) and polydispersity of tragacanth gum were 4867 × 10³ g/mol and 1.423, respectively. Considering the mechanical strengths results, applying the gum in recycled pulp improved tensile, burst, bending, and tear indices significantly. Moreover, fines retention experienced a significant increment by applying up to 2% of the gum. The pulp drainage decreased consequently by increasing the dosage of gum. The FESEM images confirmed the higher retention and bonding in paper structure by applying the gum. The results seem to open a new door for the application of different plant gums as a green additive for papermaking industries.

A 3² factorial experimental design was conducted to evaluate the effects of pH and anionic trash catcher (ATC) dosage on Cobb number (1 min), cationic demand, and conductivity in softwood kraft pulp sizing with Alkenyl Succinic Anhydride (ASA). Results indicated that acidic conditions tended to enhance ASA’s reaction with cellulose, leading to superior hydrophobicity (Cobb number, 1 min = 23 g/m² at pH 4.0 and 121 µeq/L cationic demand). Statistical analysis confirmed that pH exerted a stronger influence on ASA performance (p-value 2.0×10^-7) compared to ATC dosage (p-value 0.0297), while conductivity had minimal effect. The findings suggest that optimizing ASA application in acid conditions improves water resistance, reducing reliance on high ATC dosages. This study provides valuable insights into ASA application strategies for papermaking, particularly in furnishes that do not require alkaline conditions to retain fillers, by optimizing wet-end chemistry control for enhanced sizing efficiency.

This study investigated the effect of crushed corn cob reinforcement on the compressive strength of composite materials with a hybrid matrix based on dammar (60%) and a synthetic epoxy (Resoltech 1050 with 1058s hardener). While previous research has explored mechanical and chemical properties of such composites, as well as the role of dammar resin, the specific impact of crushed corn cob on compressive strength had not yet been addressed. Materials with reinforcement mass fractions between 50% and 67% were fabricated, each with 15 samples. Power Analysis confirmed the sample size was statistically valid. A null hypothesis—stating that crushed corn cob has no significant influence on compressive strength—was tested and rejected (p < 0.05) using one-way ANOVA. Welch ANOVA confirmed the result (Fw > 2.49), and Kolmogorov-Smirnov tests showed data normality (p > 0.05). Post hoc ANOVA with Bonferroni correction confirmed significant differences between groups. The key finding was that beyond 66% crushed corn cob content, the materials lose engineering relevance due to inadequate compressive strength.

Due to challenges associated with hydrogen storage and transportation, on-site hydrogen production has garnered significant attention. However, achieving a balance between efficiency and cost remains a critical challenge in the catalytic conversion of ammonia to hydrogen. Catalysts utilizing carbon fiber supports derived from cellulose, which contain a high carbon content, have demonstrated promising dehydrogenation activity in ammonia pyrolysis. One such catalyst component is steel fiber which contains a high content of transition metals and serves as a connection between the carbon element and the metals, which would enhance its catalytic properties. In this study, the catalytic performance of commercial steel fiber for hydrogen production via ammonia pyrolysis was investigated. Activity tests and analytical characterizations revealed that the steel fiber catalyst exhibited excellent catalytic activity, stability, and cyclic performance, enabling COX-free hydrogen production. Characterization results indicated that the catalyst contained over 80 wt% iron atoms and exhibited low surface area. The Fe atoms were further converted into stable Fe-N bonds, with the number of Fe-N bonds decreasing as the reaction temperature increased, thereby accelerating the desorption rate of nitrogen atoms on the catalyst surface and enhancing conversion efficiency.

A watery extract of Schinus terebinthifolia leaves was used as the source for producing a nanocomposite of ZnO/CuO/Se (NC ZnO/CuO/Se). Transmission electron microscopy (TEM), UV, X-ray diffraction, and scanning electron microscopy-energy were employed to characterize NC ZnO/CuO/Se. Based on the TEM investigation, the nanoparticles had an average size between 40.9 and 50.2 nm. NC ZnO/CuO/Se had potent anti-H. pylori activity, as evidenced by a zone of inhibition of 34.3 mm. The NC ZnO/CuO/Se successfully inhibited H. pylori (MIC = 15.6 μg/mL) and showed better antimicrobial activity in comparison with the control. At 75% of MBC, it dramatically decreased the production of bacterial biofilms (91.1% inhibition). High antioxidant qualities were demonstrated by the NC ZnO/CuO/Se (> 88% in the DPPH assay). It demonstrated outstanding enzyme inhibition capacity against lipase, with an IC₅₀ of 41.66 ug/mL. The IC₅₀ value of NC ZnO/CuO/Se against normal cell lines (WI38) was 593.08 ± 2.35  µg mL^–1, which is a high dose. From the overall results, NC ZnO/CuO/Se exhibited favorable biological effects in vitro as a wide-spectrum treatment for various medical uses.