Volume 18 Issue 2

Thin lamellae, corresponding to the layer components of structural glued members, i.e., 2-ply or 3-ply glued flooring, can be manufactured in re-sawing operations of kiln-dried wood blocks or in wet technologies, which currently seem to be more common because of the shorter drying time. The re-sawing process in wet technology is conducted on dedicated thin-cutting band sawing machines with stellite-tipped band saws. The goal of this research was to demonstrate the capacity of surface production (m²/ tool life) of visible layers of oak engineered flooring composites in a function of both a new band saw and a re-sharpened band saw blade. Additionally, the state of teeth of each band saw blade was examined at the end of the tool life. A series of cutting tests were performed in sawmill production conditions. The conducted tests revealed that a three times higher capacity of surface production was obtained for the new tool compared to re-sharpened tool. Additional microscopic observations of some re-sharpened teeth showed deformed plastic characteristics.

Restricted formaldehyde gas emissions and a scarcity of lignocellulosic raw materials have particleboard companies in Iran concerned about raw materials and adhesive use. The particle slenderness ratio is one of the main parameters that leads to the required mechanical characteristics of particleboard, together with the simultaneous decrease of density (raw materials) and the quantity of adhesive. The objective of this study was to evaluate the mechanical properties of particleboard composed of poplar particles with variables of density, adhesive quantity, and slenderness ratio using response surface technique. The variables were then optimized for the examined responses according to the EN 312-3 (1993) standard for the manufacturing of particleboard for domestic use as well as home and office furniture. Particleboard with minimum allowable properties according to EN 312-3 (MOR = 11 MPa, MOE = 1.6 GPa, and IB = 0.35 MPa) with a density of 0.65 g/cm³, adhesive percentage of 10.54, and a slenderness ratio of 37.5 can be produced, according to optimization findings. Through raising the density to 0.69 g/cm³ and the slenderness ratio to 46.99, the quantity of adhesive utilized in particleboard manufacturing could be decreased from 10.54 to 8.9% while keeping the minimum allowable resistances of EN 312-3  (1993) standard.

This study investigated the tensile properties and thermal behavior of virgin and hot press molded HDPE composites filled with different particle size and content of used beverage cartons which were the Tetra Pak^® cartons. The mechanical properties of the composites were positively influenced by particle size of the used beverage carton, such that the smallest particle size gave the highest tensile strength and tensile modulus. The tensile strength of the specimens decreased with increasing filler content (40 to 70 wt%), while the tensile modulus rose. Furthermore, the filler size and its content affected the thermal behavior of the specimens. Calorimetry analysis of composite specimens showed that melting temperature and enthalpy values of virgin HDPE and recycled-HDPE decreased with increasing Tetra Pak^® content. In all composite groups produced by adding Tetra Pak^®, the degree of crystallinity decreased as a function of Tetra Pak^® addition compared to the pure HDPE. Increasing particle size adversely affected the crystallization degree, which decreased with increasing particle size while the HDPE maintained its crystalline form. As for the recycled-HDPE composites, the degree of crystallization was reduced by increasing the Tetra Pak^® content, but this was still noticeably higher than that of the HDPE.

Recycled fibers are essential raw materials used by the paper industry. However, the strength of the formed paper may fall off excessively after several cycles of reuse of the fibers. Herein, the authors measured the changes in physical properties and fiber size after multiple recycling of fibers and prepared a handsheet from fiber recycled different times. Then the handsheets made with fibers that had been recycled 5 times were double-coated with nanocellulose derivatives to obtain oleophobic and hydrophobic paper. The first layer applied to the paper was cellulose nanofibril (CNF), and the second coating contained polydimethylsiloxane (PDMS) and CNF (CNFmp). The physical properties and barrier performance of coated paper were greatly improved compared to recycling paper. The water contact angle of the coated paper was as high as 139.8° and the Cobb₆₀ value was 35.18±2.15 g/m². The oil contact angle was 97.1°, and the oil kit number was 12/12.

Research into paper-based devices and ionic liquids has increased considerably in the past few years. Thus, the combination of paper-based devices with ionic liquids is also becoming an increasingly frequent research subject. However, the influence of the ionic liquid on the paper properties has been hardly considered. In this paper, the influence of a hydrophobic ionic liquid (1-butyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl)imide) on the mechanical properties of laboratory paper, isotropic and oriented, made from eucalyptus sulfate and cotton linters, is investigated. The tensile strength, elastic modulus, and breaking strain of papers saturated with ionic liquid were about 60 to 90% of the dry paper characteristics. In contrast to water, the breaking strain did not increase in the presence of the ionic liquid. This is because the ionic liquid only slightly swelled the fibers.

With the continuous development of the Internet economy, online furniture sales are increasingly becoming an important channel for consumers to purchase furniture. In order to investigate the influencing factors of consumers’ preference for purchasing furniture online, this paper aims to find out the influencing factors of online furniture consumption and their weight relations by using the literature research method and Delphi method to clarify the influencing factors of online furniture consumption, followed by the Analytic Hierarchy Process (AHP), from the Target Level, Criterion Level, and Sub-criterion Level. Weight analysis was carried out on the influencing factors of online furniture consumption. The three primary indicators included Personal Factor, Product Factor, and Service Factor. The 16 secondary indicators included Personality Traits, Revenue, Occupation, etc. An index system model was established for online furniture consumption based on the above factors. It was concluded that consumers are most influenced by the price of furniture among Product factors when choosing online furniture. The findings were consistent with the AHP model data when tested using a grey prediction model. The data from this study can therefore provide an important reference for online furniture product development and marketing promotion.

Hemicellulose was pre-extracted from poplar by the KOH extraction method. A series of activated carbons with high VOCs adsorption capacity were prepared using hemicellulose pre-extraction residue (HPR) as carbon precursor and KOH as the activator. The results showed that the pre-extraction using organic solvent (benzene-ethanol mixture) had no significant effect on the hemicellulose removal efficiency and the microporous structure of activated carbons. After the selective pre-extraction of 38.2 to 65.7 wt% hemicellulose from poplar, the final yield of activated carbons only decreased by 1.1 to 2.0%, but the pore structure of activated carbons was greatly improved. A total of 40.7 wt% hemicellulose in poplar was removed under 4 wt% alkali concentration and 3 h KOH treatment. The activated carbons prepared from HPR of poplar gave the highest BET surface area (3066 m²·g^-1) and pore volume (1.32 cm³·g^-1). The pore structures of activated carbons can be controlled to some extent by changing the removal degree of hemicellulose. The activated carbon obtained under the optimized conditions showed excellent adsorption capacity for toluene (733 mg·g^-1) and dichloromethane (184 mg·g^-1). The correlation between adsorption properties and pore structure shows that the adsorption capacities of toluene and dichloromethane were closely related to micropores (＜ 2 nm) and ultramicropores (＜ 0.6 nm) of activated carbon, respectively. The pre-extraction of hemicellulose greatly improved the volatile organic compound (VOC) adsorption capacity of activated carbons by increasing the percentage of micropores.

Inhibitory effects were evaluated for the extract from edible brown algae Ascophyllum nodosum vs. Pseudomonas fluorescens and Shewanella putrefaciens, which are tilapia spoilage organisms. Modified Gompertz and Logistic models were used to describe the inhibition effect of the extract, and both models indicated that the extract could inhibit bacteria growth by extending lag time and reducing maximum growth rate. The Lambert-Pearson model was applied to calculate the minimum inhibitory concentration (MIC) and non-inhibitory concentration (NIC) of the extract. The best-fit MIC and NIC values for P. fluorescens were 1.145 and 0.036 mg/mL, and 0.947 and 0.106 mg/mL for S. putrefaciens, respectively. Bacteriostatic assays on agar plates showed that the extract applied at concentrations higher than the MIC caused significant bacteriostatic effects, especially in S. putrefaciens. Algae extract (42 μg/disc) had inhibition zones against both P. fluorescens (1.72 cm) and S. putrefaciens (1.58 cm) in a disc diffusion assay. Treating tilapia fillets with the extract significantly reduced the total viable counts of both bacterial strains and postponed spoilage odor occurrence time (day 2 for the control group vs. day 9 for the extract treated group) during storage at 4 °C.  These findings suggest that the extract could be used as a natural anti-bacterial and preservation agent to extend the shelf life of cold storage tilapia.

A chair is a piece of furniture whose elements are loaded with relatively high forces. The strength of these elements is vital for the safety of using this type of furniture. The research aims to test the chair material system made of beech wood. The authors analyzed laminated elements with 9, 11, and 13 layers of veneers. The veneers were 1.23 mm thick, with perpendicular fiber directions in adjacent layers, and bonded with 220 g/m² of PVAc adhesive. The moisture content of the elements was 6 ± 1%. A three-point bending flexural test was performed to determine the stress-strain response of the tested three variants. A complementary numerical analysis allowed a more precise comparison of the three analyzed laminated elements variants. It was confirmed that all variants exceed the desired minimal values in chair support design. Moreover, the average strength values for tested laminated elements, differing in the number of veneers, were sufficient even with a reduced number of veneer layers. The experiments and numerical analysis results confirmed the usability of the three tested types of beech laminated elements to be used as highly loaded chair elements.

Mushroom products have been used as a biotechnological tool for many applications. Particularly, thermostable chitinase plays a vital role in biowaste management and biological control. In the present investigation, Amanita sp. was recorded in the subtropical region of Saudi Arabia, therefore, it was utilized for chitinase production using substrates chitin and dead fungal mycelia (DFM). Compared with the DFM, chitin was more suitable for chitinase activity at different temperatures and pH. Amanita sp. produced chitinase up to 70 °C, but the optimum was 50 °C. The chitinase activity was 4.98, 3.5, and 0.9 U.mg^-1 with the use of chitin, while it was 4.6, 3.1, and 0.6 U.mg^-1 with the use of DFM at 50, 60, and 70 °C, respectively. Chitinase activity was stable up to 60 °C, then it began to decrease at 70 °C. The chitinase activity was better at pH 4 and 5 than pH 8 and 9. The antifungal effect of the produced chitinase at 50 °C was more effective than at 60 °C. For instance, the Alternaria alternata colony radius was 3.50 cm and 2.26 cm at 50 °C while it was 4.35 cm and 4.13 cm at 60 °C when using DFM and chitin, respectively.