Volume 16 Issue 1

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.

The human perception of softness is an important yet complex property of hygiene tissue paper products. Softness is a function of the combination of machine technology, chemical additives, and furnish composition. As a result, it is difficult to investigate the influence of single parameters. Because no completely satisfactory method for determining the softness of furnishes is available at the laboratory scale, the influence of different fibrous materials in combination with their treatment cannot be comprehensively investigated. To work toward this possibility, this publication describes the development of a method to obtain reliable results based on laboratory handsheets using a modified tissue softness analyzer (TSA). With the help of basic statistical methods, a procedure was developed that reproducibly distinguished the influence between softwood and hardwood. To demonstrate the potential of this method, it was tested on an industrial tissue machine and the influence of four different furnishes on the softness of the semi-finished product was determined.

Drying has a major impact on the viability of sawn timber production, particularly through its influence on productivity, energy usage, and product quality. Traditionally, plantation-grown southern pine structural grade timber from Australia has been dried using high temperature (≥ 180 °C) conventional batch kilns. However, the Australian industry is showing increasing interest in continuous drying kilns because of reported cost savings and potential improvements in product quality. This study investigated the differences between continuous drying and conventional drying schedules on the radial permeability, wettability, gluability, and treatability of southern pine timber from Queensland plantations. The high temperature drying resulted in significantly lower liquid permeability compared to low temperature drying; however, there were no significant differences between drying schedules for gas permeability. For combined wood surface and core data, there were no significant differences in liquid permeability between low temperature drying and continuous drying or between continuous drying and high temperature drying schedules. For earlywood after surface machining, continuous drying resulted in the greatest wettability (based on K-values), whereas for latewood after surface machining, low temperature drying produced the greatest wettability. Earlywood had greater wettability compared to latewood. Continuous drying resulted in better gluability and treatability compared to conventional drying schedules.