Volume 19 Issue 4

Particle boards are commonly manufactured from wood-based material bound with a thermosetting adhesive based on the reaction of formaldehyde with phenol, urea, melamine, or co-condensates. The use of formaldehyde is a cause for concern due to its harmful emissions. This study investigates the use of an alternative binder combined with particles derived from a short-cycle crop as an alternative to timber derived particles. A low density particle board was developed using hemp shiv as an aggregate with a binder made with crude glycerol, derived from the waste stream of the bio-diesel industry, esterified with citric acid under heat activation. This board was characterized and found to have good mechanical properties, low thermal conductivity, and good moisture buffering. Dimensional stability was compromised by swelling when exposed to water, but it will be possible to address this shortcoming using hydrophobic additives. The acoustic properties of the board were also found to be excellent, showing potential for use as a thermally insulating acoustic separator for internal walls.

Water pollution has become a worldwide issue, particularly in developing countries. This study aimed to cleanse water contaminated with reactive red (RR-198) and reactive blue (RB-19) dyes via adsorption onto nonliving white rot fungal biomass Phanerochaete chrysosporium under different operational conditions. It was found that P. chrysosporium removed more of RB-19 than RB-198. The conditions of pH 3, temperature 50 °C, adsorbent dosage 0.6 g, particle sizes of adsorbent (0.25 mm), and contact time (30 min) were optimum for removal of the dyes. RR-198 and RB-19 were removed with levels of 78.4% and 86.4%, respectively at pH 3; 79.6% and 90.0%, respectively using 0.6 g of adsorbent dosage; 82.0% and 87.0%, respectively at 30 min; and 82.0% and 87.2%, respectively at 50 °C. Thus, dead P. chrysosporium biomass was shown to be a biosorbent for the uptake of RB-19 and RR-198 dyes.

Effects of wood temperature were studied during CNC router processing relative to the resulting surface roughness, addressing a considerable gap in wood machining research. Three wood species (Scots pine, beech, and poplar) were machined at four temperatures (-20 °C, 0 °C, 20 °C, and 50 °C) to simulate diverse climatic conditions. The experiments were conducted at varied spindle speeds (6000, 12000, and 18000 rpm) and feed rates (3000 and 6000 mm/min). Surface roughness was measured using a portable tester in accordance with relevant ISO standards. A full factorial design was used to evaluate the effects of wood species, temperature, spindle speed, and feed rate on surface roughness. Results revealed a strong correlation between processing temperature and surface roughness, with a 25.9% increase in roughness observed as temperature rose from -20 °C to 50 °C. This temperature effect was consistent across all wood species, though its magnitude varied. The study also found that wood type, spindle speed, and feed rate significantly influenced surface quality, interacting with temperature effects. These findings suggest that controlling wood temperature during processing could be crucial for maintaining consistent surface quality in industrial applications, especially in facilities operating under variable environmental conditions.

Effects of thermoplastic polyurethane (TPU) types (Recycled (R) and Virgin (V)) composites with 15 wt% and 30 wt% oakwood flour addition were studied. Selected physical, mechanical, morphological, and thermal properties of resulting polymer composites were analyzed. Test samples were manufactured using injection molding, except that abrasion resistance specimens were manufactured using a compression molding process. The findings indicated that the types of TPU and filler contents played a significant role in the density and mechanical properties of the TPU test samples. The increased oak wood flour contents in both TPU types showed improvement in density, tensile modulus, hardness, flexural strength flexural modulus, dynamic impact strength, and yield strength of the composite while decreasing the elongation at break values. In addition, both TPU types and filler contents significantly affected the densities of V-TPU and R-TPU. The TPUs type, filler content, and cycle-rpm affected Taber’s abrasion resistance values. Weight loss, which increased with the number of cycles for the control samples, decreased with increasing wood flour content. This study aimed to provide an overview of the effect of the wood flour content in the manufacturing of thermoplastic-reinforced composites and to provide a basis for further research and development efforts.

Microfibrillated cellulose (MFC) batches were produced using never-dried and commercial, dried microcrystalline cellulose (MCC) as raw materials. Mechanical treatment was applied with a Masuko grinder using different refining degrees and consisting of one to three passes through the equipment. The impact of the mechanical treatment on the particle size distribution, fiber swelling properties, particle morphology as well as rheology of the manufactured MFC gel products were investigated. In addition, specific energy consumption of the process was calculated. The MFC gel samples manufactured from the never-dried AaltoCell™ MCC, demonstrated more pronounced changes in material properties with various refining parameters than those produced from the commercial, dried MCC, which is likely attributable to the hornification effect. The most significant reduction in particle sizes and the greatest increase in fiber saturation point and rheological properties were achieved during the initial pass through the grinder. The use of never-dried MCC as the raw material resulted in a stronger MFC gel with higher storage and loss modulus characteristics. Specific energy consumption also indicated that the refining energy transfers better to the never-dried structure of MCC, and more fibrillation can be obtained with less energy when using the never-dried MCC as raw material for MFC production.

Oil palm is Indonesia’s predominant estate crop, but it generates a significant amount of unproductive stem waste. This study examined the anatomical characteristics and their relationship with density from core to bark across the bottom, middle, and top sections, providing insights for effective OPS utilization. Anatomical characteristics were observed with optical and scanning electron microscopy, and the density was measured using an electronic densimeter. The vascular bundle numbers (VBN) increased from core to bark and decreased from top to bottom. The fiber bundle area (FBA) increased from core to bark and from top to bottom. The fiber length (FL), width (FW), and wall thickness (FWT) decreased from bottom to top, whereas the fiber lumen diameter (FLD) increased. The FL of all sections decreased from core to bark. The radial variation of FW, FLD, and FWT varied in each section. The fiber at the inner section of the middle section and the whole top section mostly showed third-grade pulp quality, whereas the bottom section and outer part of the middle section were mainly fourth-grade pulp quality. The density was positively correlated with VBN. FBA, FL, and FW were negatively correlated with oven-dry density, although not significantly, while FWT and FLD were not correlated with OPS density.

This study aimed to investigate the influence of dammar resin on the mechanical properties of composite materials reinforced with corn husk and paper waste laminates. Different percentages of dammar resin (50%, 60%, and 70%) were added to the matrix while keeping the reinforcement constant. For all samples, the ratio was maintained at 40% matrix and 60% reinforcement. With the experimental results obtained, statistical analyses were conducted: two-way analysis of variance (ANOVA), Levene’s test, Shapiro-Wilk test, and ANOVA post hoc (with Bonferroni correction). The null hypothesis stated that dammar resin does not influence the mechanical properties. For all tests considered, the null hypothesis was rejected (p < 0.05), the variances were homogeneous (p > 0.05), and the data followed a normal distribution (p > 0.05). It was found that dammar resin had a significant influence on the mechanical properties as the percentage increased from 50% to 70% (p < 0.0083). For each test, based on already known premises, an explanation of the phenomenon that could occur due to the insertion of dammar resin was provided, serving to complement and validate the statistical estimations.

This work was conducted using the PicoScope signal extraction and Adobe Audition procedure, which revealed significant insights regarding the Iban traditional drum called ketebong. Three ketebong of different lengths, i.e., long, medium, and short sizes were studied. The amplitude of the long ketebong signal remains constant, showing that it had sustained its timbre for a longer duration compared to medium and short ketebong. Considering the diameter, all ketebong are almost similar, all the ketebong yield fundamental frequency at 50.15 Hz (i.e., G1# ~51.9 Hz). Although all ketebong showed similar fundamental frequency, Adobe Audition showed that the long ketebong has a brighter sound than the medium ketebong followed by the short ketebong. The purpose of this study is to derive the musical qualities of Gendang Pampat (GP), with a particular emphasis on the ketebong performance technique. The goal is to produce a rhythmic composition that integrates and reinforces a connected, expressive, rhythmic musical arrangement. The study aims to establish a framework by investigating the interlocking of rhythmic of GP to generate musical interpretation for composing a new repertoire for GP performance.

Bamboo is a type of fast-growing and renewable natural resource that is an ideal building material. In this study, the longitudinal tensile, longitudinal compressive, flexural, longitudinal shear, transverse tensile, and transverse compressive stress-strain and strength properties of bamboo with a period of 240 days were conducted to study the time-varying deterioration performance of bamboo. The results showed that the mechanical properties of bamboo decreased gradually with the passage of time. The transverse compressive strength deteriorated the most, and the longitudinal tensile strength deteriorated the least. After 240 days of tests, bamboo CCS decreased by 52.5% and UTS decreased by 25.4%. Formulas to predict deterioration of mechanical properties were put forward and validated. It was found that the nodes of bamboo influenced its mechanical properties. The deterioration degree of the test specimens with nodes was slightly higher than that of the test specimens without nodes. These findings provide evidence about the deterioration mechanism of bamboo and are significant for promoting the development of bamboo architecture.

The functional and structural features of microbial load in soil are influenced by the presence of insecticides. This study examined the impact of two organophosphorus insecticides, dimethoate and parathion on the microbial load of soil. The colony count of fungi, actinomycetes, bacteria, and nitrogen fixing bacteria was reduced after insecticides application at 7 and 14 days, but at 28 days the colony count began to increase. The growth of two white rot fungi including Pleurotus sajor-caju and Phanerochaete chrysosporium was affected by parathion, which was reflected by a decrease in colony radius to 1.85±0.05 and 0.75±0.06 cm, respectively, and by dimethoate, reflected by a decrease in colony radius to 3.33±0.12 and 1.85±0.05 cm, respectively at 40 mg/L compared to colony radius at control 7.90±0.12 and 7.50±0.06 cm, respectively. The applied low concentration (10 mg/L) encouraged P. sajor-caju and P. chrysosporium to remove up to 87.7% and 81.8% of dimethoate, respectively, and 69.20 and 68.30% of parathion, respectively compared with the decomposition at high dose (40 mg/L) at 28 days. The presence of insecticides induced the production of ligninolytic enzymes lignin peroxidase, laccase, and manganase peroxidase.