Research Articles

The aim of this study was to investigate the effect of blade type and sharpness angle on blade wear, cutting power, and surface roughness. The study was conducted on medium-density fibreboard (MDF) panels. Two blade types were analyzed (high-speed steel and cemented carbides) along with three variants of sharpness angles (40°, 45°, and 55°). Machining operations were performed on a spindle moulder at a feed rate of 6.3 m/min and rotational speed of 4500 min-1. The blade wear criterion was adopted as the loss of cutter surface area measured on the rake face. Roughness was determined using the Ra parameter, which was measured at three points on the cross-section of the MDF panel. A new, multifaceted approach to the study of cutting a narrow surface of the MDF board was used, thanks to which the interaction of such parameters as blade wear, cutting power, and machining quality as well as the type of material of the knives and their angular parameters were determined. An increase in blade wear and cutting power was recorded with an increase in cutting path, while roughness at the MDF panel cross-section varied. The cemented carbides cutter with the 45° angle may be proposed as optimal, because it showed a relatively low wear and cutting power while providing good quality of the milled surface.

The use of coconut husk sawdust and tomato stem particles at varying blending proportion was examined for the production of particle board. Boards of dimensions 350 mm by 350 mm by 6 mm were produced (coconut husk dust, tomato stem particles) at different blending proportion and addition of additive (CaCl2 at different concentrations). The physical properties (water absorption and thickness swelling) and mechanical properties (modulus of rupture (MOR) and modulus of elasticity (MOE)) were investigated. Thickness swelling and water absorption were investigated at 24 and 48 hours. The results showed that boards exhibited mean values of 0.50% to 4.16% and 2.12% to 7.00% respectively of thickness swelling at 24 hours and 48 hours respectively and 13.6% to 25.2% and 17.6% to 29.1% of water absorption at 24 h and 48 h, respectively. The boards also exhibited means of 1.00 N/mm2 to 5.25 N/mm2 and 339 N/mm2 to 3430 N/mm2 for MOR and MOE respectively. An increase in the tomato particle content caused increase in water absorption and thickness swelling, resulting in the highest water absorption and thickness swelling values. Tomato stem and coconut husk dust can be used to produce cement bonded boards after pre-treatment with hot water and preferably both sieved.

To expand the application of wood as a building material, a new type of I-shaped wood-steel beam that consisted of laminated veneer lumber and cold-formed thin-walled steel was considered in this paper. The shear performance of nine wood-steel composite beams was tested to evaluate the effects of shear span ratio, web thickness, and flange thickness. Then, the failure pattern and failure mechanism of the composite beams were analyzed. The main affecting factors of shear capacities were also discussed. Furthermore, the calculation formula for bearing capacities of composite beams was established and the calculation results were compared with the experimental results. The experimental results showed that the combined effect of composite beams was excellent. The shear capacity was mainly affected by shear span ratio and web thickness. The calculation formula of the shear capacity was established based on the shear flow theory and the specification for structural steel buildings. The formula was derived from the micro-segment balance method and the reciprocal theorem of shear stress. The calculation results according to the formula were in good agreement with the experimental values.

Foams were prepared from hydrophobically modified ethyl(hydroxyethyl) cellulose (EHEC), methyl nanocellulose, and native microfibrillated cellulose (MFC). Their film- and foam-forming abilities, stabilities, and suitabilities for foam coating on different substrates were investigated. The role of EHEC as a polymeric stabilizing agent was also studied. The EHEC-MFC foams showed greater stability and water-holding ability under pressurized dewatering than MFC foams prepared in the presence of a surfactant. A foam could be created with methyl nanocellulose without any foaming agent. Selected nanocellulose gels and foam formulations were used to coat various substrates. The surface was efficiently closed by gel and foam coatings prepared from the methyl nanocellulose and EHEC solutions, which was ascribed to good coating holdout. Coatings on papers with different levels of smoothness/density and hydrophobicity/ hydrophilicity confirmed that foam-substrate interactions affected the coat quality. The air permeance was reduced by 99% and 64% with a methyl nanocellulose coating and an EHEC-MFC coating, respectively. An EHEC-MFC coating created a hydrophobic surface on a hydrophilic substrate, and methyl nanocellulose improved the oil resistance even at a low coat weight.

The object of this study was to prepare activated carbons containing nitrogenous functional groups by a chemical method from nitrogen-containing raw materials. Fish (Ctenopharyngodon idellus) scales were impregnated with phosphoric acid (H3PO4) and activated at varied temperatures. The adsorption ability, structural characteristics, surface chemistry, and morphology of the activated carbons were characterized by methylene blue and iodine values, nitrogen adsorption, the Boehm method, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The total alkaline groups content of the activated carbon produced from fish scales was 0.4330 mmol/g, the total acidic groups was 1.68 mmol/g, the Brunauer–Emmett–Teller (BET) surface area was 501 cm2/g, and the total pore volume was 0.284 cm3/g. The average pore diameter was 1.94 nm under an activation temperature of 550 °C, an activation time of 1 h, and an impregnation ratio of 2. As a result of this study, nitrogenous functional groups that contained acid-base amphoteric adsorbent were produced.

The filamentous fungus strain Fusarium sp. ZW-21 was used for ethanol production with corncob hydrolysate. The fermentation conditions of ethanol production from corncob hydrolysate by the strain were investigated, and the effect of temperature, pH, nitrogen source, and surfactants on the ethanol production was investigated. The two factors yeast extract and polysorbate 80 were selected for further optimization by response surface methodology. The optimal conditions for ethanol production by the strain Fusarium sp. ZW-21 were 50 g/L sugar of corncob hydrolysate, 10.35 g/L yeast extract, 10 g/L KH2PO4, 0.5 g/L MgSO4·7H2O, 0.38 g/L polysorbate 80, pH 6.0, inoculum size of 1 mL/50 mL medium, and incubation temperature of 30 °C. The fermentation period was 5 d under oxygen-limited conditions, and the ethanol yield was 24.2 g/L

Laminated timber composed of small-diameter timbers reinforced with a steel bar and fiber-reinforced polymer (FRP) were fabricated to satisfy the seismic design performance level of wooden columns, and their compression strength performance was evaluated. The experimental results showed that the average compression strength of the specimen reinforced with a CFRP (Carbon FRP) bar increased by approximately 7% compared to that of the control. The average compression strengths of the specimens reinforced with a GFRP (Glass FRP) bar and a steel bar increased by 38 and 37% compared to that of the control, respectively. The unreinforced control column specimens showed a diagonal failure tendency due to the fiber slope angle, and the wood part of the reinforced specimens showed a failure mode with suppressed diagonal fracture. The average strength of the column reinforced with a CFRP plate increased by approximately 6%, but the average strength of the column reinforced with a GFRP plate decreased by approximately 5%. A comparison of the measured and predicted compression strengths of the specimens showed that the strength differences of all the specimens except the specimen reinforced with a GFRP plate were good (2 to 10.4%).

The reliability of the measurement method in determining the mass concentration of wood dust relates to the sampling time for the detection of wood particles in the ambient air of woodworking places. The aim of this study was to calculate the mass limit of detection (LOD), limit of quantification (LOQ), and the minimal sampling time (tLOD and tLOQ) for determination and quantification of samples, based on the hardwood dust mass concentration at various woodworking places in the sawmills, floor production factories, and carpentries. Determination of the mass concentration of respirable, inhalable, and total hardwood dust from ambient air was performed using personal sampling pumps and three types of filter holders: respirable dust cyclone, Institute of Occupational Medicine IOM inhalable dust sampler, and total dust open-faced filter holder. The average limit of detection amounts to 0.052, 0.083, and 0.167 mg for respirable, inhalable, and total hardwood dust, respectively. The minimal detection sampling time for collecting all observed types of dust fractions ranged between 1.12 h and 1.72 h. The minimal quantification time for all collected hardwood dust samples ranged from 3.75 h to 5.51 h. Pearson’s correlation test showed that the reliability of the measurements was affected more by the dustiness of the workspace than the real sampling time.

Cast polyamide 6 (PA6G), trade name Castamide, is a semi-crystalline polymer widely used in the engineering plastics industry. There is a need to recycle valuable waste (W)-PA6G generated during part manufacturing of this polymer (approximately 30%). This study attempts to utilize W-PA6G in the manufacture of wood-plastic composites as a polymeric matrix. The effect of lignocellulosic filler type (FT) and filler content (FC) on the mechanical, morphological, and thermal properties of W-PA6G-based composites were investigated. During manufacturing, N-butyl benzene sulfonamide (N-BBSA) and lithium chloride (LiCl) were utilized as a plasticizer and a melt temperature-lowering salt, respectively. The rice husk (RH) and Uludağ fir wood flour (WF) filled W-PA6G-based composites were successfully manufactured using a combination of extrusion and injection molding. Compared to RH filled composites, WF filled composites provided better tensile and flexural properties (both strength and modulus) at 20% and 30% filler contents. Morphological study showed the nonhomogeneous distribution of fillers in the polymeric matrix. Lignocellulosic filler resulted in reduced melting temperature and crystallinity of W-PA6G-based composites. This reduction was more pronounced in RH filled composites.

This paper presents research conducted on pine timber sawn from logs obtained from three different forestry regions in western Poland. Forestry regions were characterized in terms of i.e. annual mean temperature and rainfall distribution, soil, growing stock, and technical quality and type of forest. The timber logs were classified in three different quality classes, A, B, and C as per PN-D 95017 (1992). The coefficients of correlation were calculated for pairs of the studied properties (density, modulus of elasticity (MOE), and static bending strength (MOR)) considering the forestry region of origin of the different quality logs. The statistical analysis revealed that there is a strict correlation between quality class of logs, geographical origin in terms of technical quality of forest, and physical and mechanical parameters of sawn timber.