Research Articles

Fatty acid alkyl esters (FAMEs) derived from waste vegetable oils and non-edible oil sources are the most attractive alternative liquid biofuel in the energy field. Substitute methyl esters derived from waste cooking oil (WCO) have a lower induction period (3.12 h) and do not satisfy the Biodiesel EN 14214:2012 Standard (8 h). In this study, concentrations of 100, 250, 500, and 1000 ppm of four different types of phenolic antioxidants—butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tert-butyl hydroquinone (TBHQ), and propyl gallate (PG)—were used to examine oxidative stability and improve fuel quality. PG (250 ppm) showed the most effective result of 18 h to 12.17 h of the induction period of 6 months of storage. Antioxidant effectiveness increased with regard the oxidative stability of waste cooking oil methyl ester in the following order: BHT

Electrical resistance and resistivity were measured with various types of electrodes to evaluate the moisture content of wood. The conventional two-pin method, electrically conductive fabrics, and multi-pin electrodes were used to measure the electrical resistance of Japanese larch (Larix kaempferi) wood, and a four-pin probe was used for resistivity measurements. The resistance in the longitudinal direction measured with the two-pin electrode was slightly affected by the dimensions of the wood sample, whereas the resistance measured with the conductive fabric and multi-pin electrodes was clearly affected by the end surface area in contact with the electrode and the length between electrodes. The resistivity calculated from the relationship between the electrical resistance and sample dimensions also showed differences based on the sample dimensions. The least squares regression model trained with the resistance data based on the two-pin method predicted the moisture content with a high coefficient of determination of 0.986. The four-pin probe produced the most stable resistivity regardless of the sample dimensions, making it a feasible approach for the moisture evaluation of large wood members.

The involvement of wood decay fungi and the importance of their enzymes in polyethylene degradation is well documented. Therefore, decay-resistant hardwood associated fungi should be better degraders with their versatile enzymatic systems. In the current study, decaying hardwood associated fungi were isolated and their ability to degrade low-density polyethylene (LDPE) was assessed. Thirty-three isolates were identified by sequencing the internal transcribed spacer region of nuclear ribosomal DNA. Randomly selected isolates were tested for laccase producing abilities. Three species were selected to test their potentials in LDPE sheet degradation. Fungi were incubated in Czapek-Dox broth containing 20-micron LDPE sheets at room temperature for 60 days. The biodegradation signatures were assessed by analyzing the changes in structural characteristics of LDPE using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), percent reduction of tensile properties, and weight loss. FTIR analysis revealed changes in certain functional groups compared with the control, indicating chemical changes resulting from the treatment. LDPE sheets incubated with fungi showed cracks and holes under SEM analysis, percent reduction in tensile properties, and weight loss, which are the signatures of degradation. This study revealed that the hardwood decaying basidiomycetes, Phlebiopsis flavidoalba, Schizophyllum commune, and Phanerodontia chrysosporium have the potential for in vitro LDPE degradation.

Cross-laminated timber is a wood product with excellent fire resistance and mechanical performance that is often used in tiny houses. Using the ASTM standard E564, the shear performance of cross-laminated timber wall panels, with and without openings, were investigated in this study. The specimens were made of spruce-pine-fir IIc lumber and installed on a test platform using high-strength bolts passing through them. This connection mode limited the displacements obtained in the test, primarily the shear displacements and rocking displacements. By comparing the static load test data of the three specimens with openings and the one without an opening, it was found that openings reduced the shear strength and shear stiffness. For the same sized rectangular opening, the shear stiffness of the cross-laminated timber panel was less when the wider side was horizontal (normal to the direction of the applied force). The shear stiffness of the cross-laminated timber wall panels can be effectively improved by reinforcing the areas near the openings with metal sheets. With reinforcement, the shear strength did not change drastically, but the damage to the cross-laminated timber wall panels was significantly reduced.

In the described study, the relationships between the percentage and structure of selected lignocellulosic components and the efficiency of their anaerobic digestion and the quality of the produced biogas were analyzed. This research included various lignocellulosic raw materials. The biogas efficiency and quality tests were carried out according to DIN standard 38 414-8 (1985) and VDI standard 4630 (2016). Multiple TAPPI standards and the Seifert method were used to determine the chemical composition of the lignocellulose materials. Lignin structure analysis was performed using Fourier transform infrared spectroscopy. Wide-angle X-Ray scattering analysis was used to determine the degree of crystallinity of cellulose. The biogas was positively correlated with C=O and the syringyl to guaiacyl ratio, and negatively correlated with the crystalline structure of cellulose, lignin, cellulose, and extractives. In addition, methane was positively correlated with holocellulose and extractives and negatively correlated with the crystalline structure of cellulose, cellulose, substances soluble in NaOH, and the OH groups. The found independent features accounted for 86.0% of the biogas variability and 68.0% of the methane variability.

The effects of the moisture content, density, and striking direction of a hammer on the vibrational characteristics, i.e., the fundamental frequency and dynamic modulus of elasticity, of four wood species, i.e., poplar (Populus tomentosa), mahogany (Swietenia mahagoni), beech (Fagus orientalis), and ash (Fraxinus excelsior), commonly used in wood products were investigated, aiming to provide basic evidence for the nondestructive testing of wood materials. The results showed that the effect of the wood species on the fundamental frequency, dynamic modulus of elasticity, and static modulus of elasticity was statistically significant. The dynamic moduli of elasticity of the four wood species were higher than the corresponding static moduli of elasticity. The effect of the striking direction on the dynamic modulus of elasticity was not significant, indicating that no matter where the hammer struck, i.e., radial and tangential surfaces, the fundamental frequency was essentially constant. Negative relationships were found between the fundamental frequency and the density and moisture when the data of the four wood species were viewed as a population sample. The vibrational characteristics of each wood species varied, which can be applied to the nondestructive testing of wood.

Based on the solubility parameter theory, the Hansen solubility parameters of various solvents were calculated and compared to predict the solubility of cellulose in various solvents, which illustrates the feasibility of Hansen solubility parameters to predict the solubility of cellulose in solvents. This paper aims to make a more accurate prediction in advance when finding suitable cellulose solvent system, and then to reduce the burden of cellulose solvent selection.

Fused deposition modeling (FDM) 3D printing technology is the most common system for polymer additive manufacturing (AM). Recent studies have been conducted to expand both the range of materials that can be used for FDM and their applications. As a filler, wood flour was incorporated into poly lactic acid (PLA) polymer to develop a biocomposite material. Composite filaments were manufactured with various wood flour contents and then successfully used for 3D printing. Morphological, mechanical, and biodegradation properties of FDM 3D-printed PLA composites were investigated. To mitigate brittleness, 5 phr of maleic anhydride grafted ethylene propylene diene monomer (MA-EPDM) was added to the composite blends, and microstructural properties of the composites were examined by scanning electron microscopy (SEM). Mechanical strength tests demonstrated that elasticity was imparted to the composites. Additionally, test results showed that the addition of wood flour to the PLA matrix promoted pore generation and further influenced the mechanical and biodegradation properties of the 3D-printed composites. An excellent effect of wood flour on the biodegradation properties of FDM 3D-printed PLA composites was observed.

Furfural (F) cannot be easily polymerized like furfuryl alcohol, but it is an aldehyde that can react with urea (U) to make a polymeric network. The possibility of preparing F/U polymer along with an acidic catalyzer (maleic anhydride; M) was evaluated as a means to improve some selected properties of birch (Betula pendula) wood. The F+U/M resin was introduced into the wood with a double treatment technology. The first step involved dilution of F in water and methanol, and the second step was immersion in a U/M aqueous solution. The color of treated wood was darkened after resin curing from brown to a spectrum of black depending on the amount of loaded resin. The 60 to 80% of materials were converted to a non-leachable polymer based on the different formulations. The water absorption and volumetric swelling of the treated samples decreased with an increase in weight percent gain (WPG). The analysis of mechanical strength showed that treatment with F + U/M reduced to some extent the hardness and the impact bending of wood, while modulus of rupture, modulus of elasticity, and compression parallel to the grain with WPG were increased. The exposure of the samples to the accelerated weathering showed noticeable changes in color and roughness.

The “Selva Central” of Peru is characterized by its forest species richness that produces quality wood for countless uses. Therefore, it is necessary to identify the wood and its macroscopic anatomy, which is an important tool for the botanical identification of tree species. For this purpose, 13 sawmills located in 3 provinces were selected that exploit several tree species of “Selva Central”. Sampling of representative woods was carried out, identified by common names and, in the laboratory, they were polished, examined, and grouped by the similarity of the macroscopic anatomical structure, leading to the tree species identification. Twenty tree species were identified, belonging to 17 genera, with emphasis on the Lauraceae and Fabaceae families. However, Moraceae, Meliaceae, Lecythidaceae, Euphorbiaceae, Bignoniaceae, Myristicaceae, Combretaceae, and Burseraceae families were also identified. The anatomical structures of all the identified tree species were described, transversal and longitudinal tangential cross section images were collected, and a species identification key was constructed. The implications and importance of tree species identification via wood anatomy were discussed, in terms of controlling forest exploitation, traceability of the production chain, and the future development of an artificial intelligence tree-species identification method.