BioResources (E-Journal)
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Varnish Adhesion Performance of Densified and Thermally Post-treated Beech and Pine Wood
No full textThe adhesion strength was studied for water-based nano-varnishes applied to densified and thermally post-treated beech (Fagus orientalis L.) and pine (Pinus sylvestris L.) woods. Specimens were thermo-mechanically densified at different compression ratios (20% and 40%) and temperatures (110 °C and 150 °C), and subsequently thermally treated at 190, 200, and 210 °C. One-component (OWB) and two-component (TWB) nano-varnishes were applied, and adhesion strength was evaluated using the pull-off test. Results revealed that the modification processes greatly influenced adhesion, with distinct effects depending on wood species. For untreated beech, densification improved adhesion strength, whereas for pine, it either reduced or did not cause a pronounced change. A primary finding was that thermal treatment decreased adhesion strength for all specimens in a temperature-dependent manner; higher temperatures led to progressively lower adhesion. This decline was more pronounced in densified specimens (especially beech wood). The reason was attributed to the cohesive failure within the weakened wood substrate rather than adhesive failure at the varnish-wood interface. Across all treatment conditions, TWB varnish exhibited superior adhesion compared to OWB. The study concluded that densification may have a species-specific effect, while thermal treatment fundamentally reduces wood surface strength and, consequently, varnish adhesion
Mechanical and Thermo-Mechanical Behaviors of Cork Filler-Reinforced Epoxy Composite
No full textMechanical characteristics were studied for epoxy composites reinforced with cork fillers, analyzing various loading conditions of fillers ranging from 0 to 30%. The fabrication utilized a hand layup method. The results indicated that the composite mechanical properties, glass transition temperature, and storage modulus were optimal at a 20% natural filler loading. Dynamic mechanical analysis (DMA) showcased exceptional energy absorption capabilities up to 110 °C. Thermogravimetric analysis (TGA) showed that the bio-filler degraded quickly, leaving 0.3% remnant, but the cork filler composite (25% v/v) showed an even residue concentration of 9%. Additionally, biodegradability tests showed weight loss in a soil burial test with the addition of bio-filler to the composite
Paper Fingerprint by Forming Fabric: A Univariate Feature Selection Approach Using Periodic Marks Analysis
No full textEvidence by which to confirm the location and approximate manufacturing date of document paper is a critical task in forensic investigations, particularly in cases involving suspected forgery or document manipulation. In this study, periodic marks formed during the papermaking process were analyzed using light-transmitted images captured by a two-dimensional lab formation sensor. Step and angle data from the top five intensity peaks were extracted and used to train tree-based classification models. To handle directional symmetry, a modulo 180° transformation was applied to the angle data. The random forest (RF) classifier outperformed decision tree (DT) and extreme gradient boosting (XGB) models, achieving the highest F1 score. Feature importance analysis revealed that the step and angle at the third intensity level were the most discriminative features, likely reflecting structural characteristics of forming fabrics or drainage patterns. A simplified univariate strategy using these features also showed potential for estimating production periods. However, differences between the top and bottom surfaces—particularly in twin-wire systems—introduced classification bias, highlighting the need to separately classify paper sides in forensic datasets. Overall, this study demonstrates the feasibility and limitations of using periodic mark analysis for document dating
Comparative Review of Natural and Synthetic Binders for Microbial Fuel Cell Electrodes
No full textMicrobial fuel cells (MFCs) are a promising technology for renewable energy and environmental remediation. The performance of MFCs is greatly influenced by the binder materials used on the electrodes, which must have good conductivity, stability, and compatibility with microorganisms. Synthetic binders, such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyuretane (PU), geopolymer binder, and polyvinyl alcohol (PVOH), are commonly used due to their electrochemical properties but are expensive and not environmentally friendly. In contrast, natural binders, such as chitosan, sucrose, carboxymethylcellulose (CMC), and vegetable oils, provide cost-effective and environmentally friendly alternatives. This review synthesizes findings from various studies, comparing the electrochemical properties, stability, and sustainability of chemical and natural binders. The review identifies key research gaps and suggests future directions to improve the performance of natural binders in MFCs, making them more viable for large-scale applications in terms of cost and environmental impact. Natural binders have the potential to be a sustainable alternative in MFC electrode development
A Comparative Approach to Sustainable Paper-based All-Cellulose Composite Production: NaOH/urea versus AlCl3/ZnCl2
No full textAll-cellulose composites were prepared using a novel AlCl3/ZnCl2 molten salt solvent system, which allows for fabrication at room temperature. Unlike conventional NaOH/urea solvent systems, the proposed solvent demonstrates enhanced solubility and processing efficiency without requiring low-temperature conditions. The composites produced at room temperature, while they displayed enhanced wet strength properties, possessed a rather poor tensile strength and Young´s Modulus. When the composites were treated with the molten salt solvent system at a higher temperature, the composites displayed a marked performance improvement, suggesting that the solvent’s efficiency is temperature dependent. At higher temperatures comparable performance to NaOH/ urea produced all-cellulose composites was demonstrated. This dual advantage, room-temperature processing and improved properties at elevated temperatures, demonstrates the versatility of the AlCl3/ZnCl2 molten salt solvent system and the potential for energy-efficient, scalable production of sustainable all-cellulose composites
Togunggak: Traditional Music of Kadazandusun
No full textThe togunggak is a traditional musical instrument made of bamboo. This work observed the unique sound characteristics to define the notes using Fast Fourier Transform (FFT) via a picoscope. The sound characteristics are represented by the dominant frequency with the corresponding intensity. The note of the biggest (tog. 6) to the smallest (tog. 1) bamboo tube is recorded as from G3 to G4. This work reveals that tog. 2 to tog. 5 for togunggak A produce the notes E4, D4, B3, and A3, which is not similar to togunggak B, i.e., E4, D4, C4, Bb3. All bamboo tubes produced fundamental frequency with the presence of two lower partials at 100 Hz and 200 Hz and weaker overtones (except tog. 6) in their frequency spectrum. Using symbol S for semitone dan T for tone (i.e. 2 semitone), the note interval of the tog. 6 to tog. 1 can be presented as TT2TT2T i.e., the G3, A3, B3, D4, E4, G4 note interval are presented by G3-A3 as T, A3-B3 as T, B3-D4 as 2T, D4-E4 as T and E4-G4 as 2T. The time frequency analysis (TFA) displays all the spectrograms with distinct prominent fundamental frequency peak
Mechanical and Finite Element Analysis of a Tree Microstructural Model Derived from Softwood Annual Rings
No full textA Scotch pine wood annual ring (AR) structure was modeled using AutoCAD and SolidWorks software. The same AR was separately modeled to create earlywood (EW), transition wood (TW), and latewood (LW). All 3D models were additively manufactured using Hyper PLA material and Creality 3D printer. Compression tests were performed to obtain load-deformation curves. The maximum force, compression strength (CS), and deformation at 500N load were determined. The EW presented the highest deformation while LW presented the highest CS. The TW and AR displayed intermediate behaviors. Finite Element Modeling and Analysis (FEM&A) was performed to compare with the experimental results. The numerical results presented considerable high deviations from the experiment. Around 78.7%, 41.7%, 89.3%, and 52% differences were observed for AR, EW, TW, and LW, respectively. Therefore, the capability of the model for prediction of mechanical behavior was not found to be successful. The essential reason for these discrepancies is the contrast between the orthotropic nature of wood and partially anisotropic nature of 3D printed models even if the filament is isotropic material. However, it should be taken into consideration that such high differences are not abnormal for the wood material even if the tested samples belong to the same log because of the variations in the material due to sampling details such as cutting location, orientation, etc. Furthermore, when considering the 3D printing parameters such as infill density, printing orientation, layer height, etc., the FEM&A results can be considered partially successful, although the differences were high.
Multimodal Evaluation of Warmth Perception in Wood: An Experimental Study Based on Visual, Tactile, and Visual-Tactile Interactions
No full textThe inherent warmth of wood is widely valued in design applications, yet the mechanisms underlying its perception across different sensory modalities have not been fully explored. The aim of this work was to investigate the physical properties that influence warmth perception of wood across different species and surface treatments, and to clarify the respective contributions of visual and tactile warmth during multisensory integration. In this work, 10 material samples were technically characterized and their perceived warmth was evaluated by participants under three conditions: vision-only, touch-only, or combined visual-tactile interactions. Infrared thermography was used to quantify material temperature changes. Results showed that color dominated warmth perception under the visual assessment, while thermal properties and hand-material interface temperature differences significantly influenced tactile warmth perception. Wood species exhibited substantial effects on warmth perception, whereas surface treatments showed limited impact. Visual-tactile warmth perception was significantly positively correlated with both modalities, predominantly mediated by tactile inputs during direct contact, with visual characteristics providing critical complementary information. These findings advance the understanding of wood’s multisensory warmth perception and provide valuable insights for user-centered wood space and product design
Response Mechanism of Extracellular Laccase Activity of Lyophyllum decastes to Cultivation Substrates and Subculture
No full textDifferent fermentation substrates were employed to investigate the variation patterns of lignocellulolytic enzymes in Lyophyllum decastes and the changes in laccase activity in subculture. The results showed that the activities of Lac, CMCase, and Xyl produced by the L. decastes F1 strain in liquid fermentation were significantly affected by different cultivating substrates. The optimal primary substrate for inducing Lac secretion in L. decastes F1 strain was corncob, followed by cottonseed hulls. The best supplementary substrate for Lac induction was soybean meal. The addition of corn cob and wheat bran was found to significantly stimulate the secretion of CMCae and Xyl in L. decastes F1 strain. The addition of different cultivation substrates enhanced Lac production in L. decastes subcultured strains (F1, F5, F10), but strains subjected to serial subculturing exhibited progressively diminished laccase production. The highest laccase activity detected in the fastest-growing subcultured strains within identical solid cultivation substrates demonstrated a phase-specific positive correlation between mycelial growth and extracellular laccase secretion
Evaluating Vegetable Oil Epoxidation Efficiency on Properties of Eucalyptus Wood: Thermal and Thermo-chemical Processing
No full textThe applications of wood are limited by its hygroscopicity and resulting dimensional changes, which reduce its service life for outdoor conditions. Modification methods develop the usages of wood-based products by altering the structure. This study compared the effect of oil heat treatment (OHT) with raw (SO) and epoxidized soybean oil (ESO) at different temperatures relative to the practical properties of eucalyptus wood. Fourier transform infrared spectra confirmed hemicellulose degradation with increasing temperatures of ESO-treated specimens. With increasing temperature, ESO darkened the specimens compared to SO. Thermal modification at the highest temperature in ESO resulted in a weight loss of modified specimens and the lowest density, with more hydrophobicity and dimensional stability compared to the SO-modified specimens. Based on bending data, unlike modulus of elasticity (MOE), modulus of rupture (MOR) did not show a statistical difference between the two types of oils, except at 150 °C. At 200 °C, the specimens modified with ESO exhibited lower hardness than SO. The impact resistance of 150 and 175 °C/ESO modified specimens was higher than SO specimens. In summary, functionalized vegetable oil significantly improved physical characteristics compared to SO, with obvious improvement in impact strength at 150 °C