Research Articles

The possibility of using beech wood sawdust and hazelnut husk waste generated during the cultivation of Pleurotus ostreatus mushrooms as a filler in polycaprolactone (PCL)-based biocomposite films was investigated. Chemical and physical properties of the PCL biocomposites were determined. The beech sawdust and hazelnut husk were exposed to degradation for 73 d and 78 d, respectively, in slightly acidic environments at a relative humidity of 75%. The degraded materials caused the holocellulose and lignin contents in the PCL biocomposites to decrease, while the cellulose and α-cellulose contents increased. In general, as the lignocellulosic waste content increased, the tensile strength (TS) and elongation at break (EatB) values decreased and the tensile modulus (TM) and water absorption (WA) values increased. It was determined that the PCL biocomposite with the degraded beech sawdust absorbed more water than the composite with the undegraded beech sawdust. On the other hand, the PCL biocomposite with the degraded hazelnut husk absorbed less water than the composite with the raw hazelnut husk.

Lignocellulolytic white-rot fungi allow the bioconversion of agricultural wastes into value-added products that are used in a myriad of applications. The aim of this work was to use corn residues (Zea mays L.) to produce valuable products under solid-state fermentation (SSF) with Pleurotus ostreatus. White-rot fungus P. ostreatus was isolated from maize silage (MS) and thereafter it was inoculated on MS as substrate and compared with maize stover (MSt) and maize cobs (MC) to determine the best lignocellulosic substrate for the production of lignocellulolytic enzymes and extracellular protein. The MS gave the highest productivity of CMCase (368.2 U/mL), FPase (170.5 U/mL), laccase (11.4 U/mL), and MnPase (6.6 U/mL). This is compared to productivity on MSt of 222 U/mL, 50.2 U/mL, 4.55 U/mL, and 2.57 U/mL, respectively; and productivity on MC at the same incubation period as 150.5 U/mL, 48.2 U/mL, 3.58 U/mL, and 2.5 U/mL, respectively. The levels of enzyme production declined with increasing incubation period after 15 and 20 days using MS and MC, respectively, as substrates. Maximum liberated extracellular protein content (754 to 878 µg/mL) was recorded using MS, while a low amount (343 to 408 µg/mL) was liberated with using MSt and MC.

The growing interest in wood accessories has focused scientific research attention on wood cutting with small diameter tools. A problem that may arise when drilling wood is the phenomenon of wandering – when the hole is not made in the designed place. The difficulty in studying small diameter drill holes (0.5 mm to 0.9 mm) is due to the difficulty of automatic measurement. The development of an appropriate methodology may allow for the observation of this phenomenon without the need for high-class hardware and expensive software. This article presents the results of tests carried out on nearly 500 samples made of various wood-based materials (high-density fiberboard (HDF), medium-density fiberboard (MDF), chipboard, and plywood) in terms of the usefulness of the OpenCV computer vision library for the determination of wandering.

The interrelationships among specific gravity (SG), modulus of elasticity (MOE), and strength (modulus of rupture, MOR) are largely the foundational basis for non-destructive evaluation and testing. Resource monitoring and commercial structural lumber production often rely upon such non-destructive evaluation to predict the bending and/or tension strength of individual members. These technologies require routine calibration. In addition, it is important to know the extent to which a given resource may change over time. To that end, this study investigated the relationship among SG, MOE, and MOR of small clear specimens from three samples taken across an approximate 50-year period; 1965 to 2018. Coefficients of determination among these variables are presented along with the prediction equations. These findings can be used to gain insight into the reliability and stability of these relationships over time.

Straw mulch mat is a promising alternative to petroleum-based plastic mulching film. The straw pretreatment process parameters influence the mechanical properties of the mat. To explore the effect of pretreatment process parameters on physical properties of wheat straw mulch mat, a five-factor and five-level central composite design (CCD) methodology was studied. With response surface methodology (RSM) analysis, the effects of parameters (soaking water temperature, soaking time, processing speed, manufacturing temperature, and manufacturing pressure) on dry tensile index and wet tensile index of original film, and initial beating degree of the straw pulp were reported. The optimal technical parameters were optimized as soaking water temperature 90 °C, soaking time 1.5 h, manufacturing pressure 1.5 MPa, processing speed 83.5 to 87.8 r/min, and manufacturing temperature 95 to 100 °C. With the optimal condition, the dry tensile index, wet tensile index, and initial beating degree were higher than 8 N·m/g, 4 N·m/g, and 17 °SR, respectively. With this pretreatment of raw materials, the wheat straw mulch mat would meet the demands of mechanical properties for agriculture mulching after adding chemical additives.

In recent years, circular saw blades with thinner kerfs have been in high demand for improvement of the production yield of wood-based materials and the reduction of sawdust. In the case of ripping of solid wood, the number of teeth of a circular saw blade is normally set to 40 or 50, with a diameter of 305 mm, which allows less cutting resistance and smooth exhausting of sawdust. However, at certain rotational speeds, self-excited alternate-tooth vibration can easily occur in circular saw blades with such thin kerfs and so few teeth. Therefore, the cutting surface quality tends to be worse. In this study, the mechanism of this self-excited alternate-tooth vibration was clarified. The vibration mode and frequency were predicted by the finite element method. In addition, a circular saw blade with a body thickness 1.5 mm and 50 teeth was employed for wood-cutting experiments. The rotational speed range of the self-excited alternate-tooth vibration modes and their frequencies were investigated. When a double of the tooth passage frequency was slightly higher than the frequencies of the alternate-tooth vibration modes, an alternate-tooth vibration of the regenerative chatter type was excited, owing to the forces on the sides of the tooth.

The bark of Pteroceltis tatarinowii is one of the main raw materials for the manufacturing of Xuan paper. In order to guide the production of Xuan paper, the anatomical properties and chemical compositions of the bark and branch wood from P. tatarinowii at different years of age were analyzed in this study. The results from a variation analysis of the anatomical properties indicated that the ratio of the length to width of the bark and branch wood was greater than 30, while the ratio of the lumen diameter to the wall thickness was less than 1. Furthermore, there were significant differences in the length and the ratio of length to width of the bark and branch wood. The results from a variation analysis of the chemical composition indicated that the lignin content of branch wood at various ages (years) was greater than the lignin content of bark. Additionally, the cellulose extractive and pentosan contents of the branch wood was less than the contents in the bark. Based on the analysis of the anatomical and chemical composition, barks that were 2 to 3 years old were the most suitable raw materials for the manufacturing of Xuan paper.

This study investigated the effect of pressurized temperature on the thermal, mechanical, and morphological properties of nanocomposites made from recycled polyethylene with the weight ratio of 50%. Nanosilica was applied at 3 levels (0, 4, 8 %) and wood flour had a weight ratio of 50%. High-density polyethylene (HDPE) went through multiple procedures. It was found that by increasing the nanosilica content, the tensile and flexural strength properties, the residual ash content, and the thermal stability increased along with a reduction in the tensile and flexural modulus and impact resistance. As the temperature increased, the tensile and flexural strength and modulus and the impact resistance decreased. Scanning electron microscopy (SEM) images revealed that samples with 8% nanosilica showed different polymerization than the wood flour particles.

Naturally durable wood species such as western juniper (Juniperus occidentalis) are a potential source of bio-based wood preservatives for the improvement of non-durable timber species. This research investigated the durability of southern yellow pine (Pinus sp.) and western juniper lumber or strandboard. Single layer panels were made with six different types of wood or wood treatments: southern yellow pine, mixed juniper sapwood and heartwood, sapwood, heartwood, sapwood strands impregnated with juniper oil prior to and after panel manufacturing. Panels were fabricated with 560 kg/m3 oven-dry density with 5% of PF resin and 0.5% of wax. Durability testing was performed with the brown rot fungi Gloeophyllum trabeum and Rhodonia placenta and the white rot fungus Trametes versicolor. Internal bond as a crucial parameter of OSB was measured. Tests revealed that juniper heartwood and juniper heartwood strandboards were highly decay resistant, and juniper oil pre- and post-impregnation strandboard manufacture imparted increased resistance to decay against one brown rot fungus, Gloeophyllum trabeum. Juniper strandboard manufactured from non-impregnated strands showed significantly higher internal bond than pine. These results suggest there is excellent potential for manufacturing highly decay-resistant OSB from juniper, especially from heartwood and that juniper oil can increase the durability of juniper sapwood strandboard.

In the flow forming technique of wood, a wood block is flowed into metal dies to mold the material into a three-dimensional complex shape. The purpose of this study was to investigate the effect of molding load and the mechanical properties of the molded material in the case that wood as a raw material was irradiated with electron beam (EB). The EB-irradiated wood board was impregnated with thermosetting resin and was subsequently molded into the material by adding pressure and heating in a closed metal die. It was found that the molding load of the impregnated wood was decreased with increasing the EB absorbed dose. The mechanical properties of the molded material were evaluated using modulus of elasticity (MOE) and modulus of rupture (MOR) in a three-point bending test. With increasing EB dose, MOR decreased greatly, while MOE decreased slightly. The EB irradiation on raw wood made it possible to mold the material at low load, though higher dose irradiation caused larger decreases in the mechanical properties.