Research Articles

Thermal modification mechanisms and their effects on physical and mechanical properties of native Amazon hardwoods are not yet completely understood. It is expected that such treatments can improve the properties of low-value Amazonian woods and sapwood residues. This study aimed to investigate the impact of heat treatment on the swelling and mechanical properties (strength and stiffness to Static Bending and Janka hardness) of tauari wood (Couratari spp.), a low-value Amazonian hardwood. For this, tauari wood samples were thermally modified in an electric oven under hot air irradiation at final temperatures of 160 °C, 170 °C, 180 °C, 190 °C, 200 °C, and 210 °C for 2.5 h. The main results showed that thermal modification increased the hydrophobicity of tauari wood without any noticeable effects on the mechanical behavior of the wood up to 200 °C. It was stated that up to 200 °C thermal modification is beneficial in terms of gains in hydrophobicity. In contrast, above 200 °C, despite an increase in hydrophobicity, consistent decreases in strength (MOR) and hardness were observed.

Effects of temperature dependence and relative humidity were studied relative to the thermal conductivity of heat-treated pine and heat-treated beech, which are frequently used for building construction. Pine and beech wood were exposed to heat treatment at 180, 200, and 220 °C in nitrogen gas for 2 h. As a result, the thermal conductivity values of the heat-treated wood decreased as the temperature of the heat treatment process increased and relative humidity increased. However, thermal conductivity of wood became more stable after heat treatment under relative humidity changes. The thermal conductivity values increased with rising mean plate temperatures, while the temperature dependence of the heat-treated wood was not affected by the relative humidity changes. Consequently, heat-treated wood, with variable humidity without excessive heat changes, can be preferred for the construction of buildings.

Effects of pressure, dewatering time, and sludge cake thickness on the dewatering of wastewater sludge by the hydraulic dehydrator under the condition of adding CaO and FeSO₄ were analyzed using the response surface method (RSM). It was found that when the parameters of pressure, dewatering time, and sludge cake thickness were changed, the trends of dewatering papermaking sludge and municipal sludge were similar under the condition of raw sludge with 3% CaO and 3% FeSO₄. Specifically, the increase of pressure and dewatering time promotes the dewatering effect of wastewater sludge, and the thinner the sludge cake is, the better the dewatering effect. The water content can be affected by the change of pressure, dewatering time, and sludge cake thickness. In response surface analysis, the model F-value and coefficient of determination (R²) were 541.43 and 0.9986, respectively, indicating high significance and good correlation. In the model, the change of pressure, dewatering time, and sludge cake thickness affected the water content of paper sludge. Particularly, the increase of pressure and compression time enhanced the dewatering efficiency. The thinner the sludge cake was, the better the dewatering effect of paper sludge was.

Bambusa arundinacea (Retz.) Willd. is a large and thorny bamboo species used for construction and scaffolding purposes. Bamboo fibers, which are an important part of bamboo, give bamboo its excellent mechanical properties. The goal of this work was to get more information about fiber in order to learn more about bamboo material. It was tested for different ages, heights, and radial positions using the nanoindentation method. The results showed that the mean values of indentation modulus of elasticity and hardness of this species were 20.79 GPa and 497.01 MPa, respectively, and that the mechanical properties of the fiber cell walls were less affected by the three factors and were generally consistent. In regards to the age factor, it had little effect on the indentation modulus of elasticity, while the hardness increased slightly with age. The indentation modulus of elasticity and hardness tended to increase with increasing height. The fiber strength was relatively stable in different parts of the radial direction.

Water contamination has reached crisis proportions due to the rapid development of industrial operations. Humans, animals, and aquatic life are all at risk of accumulating non-biodegradable heavy metals and dyes in the water supply. The adsorption process using activated carbon was identified as the most efficient, economical, and facile method. Activated carbon has gained widespread popularity because of its specialty as an adsorbent in wastewater treatments. In addition, the abundance and inexpensiveness of local bamboo can be explored in producing a cheaper and more sustainable source of commercially activated carbon. Hence, this study aimed to investigate the optimal parameters for effective activated carbon production using G. albociliata, a bamboo species by characterizing its material properties and adsorption ability. Fourier infrared spectra and scanning electron microscopy were employed to identify the functional groups and surface porosity of the activated carbon produced. The adsorption abilities of the heavy metals were determined by atomic adsorption spectroscopy and via the adsorption of dyes by ultraviolet-visible analysis. This study revealed that the bamboo-based activated carbon was a powerful adsorbent and a non-toxic agent for wastewater treatment. The copper, zinc, and methylene blue would be removed effectively by more than 99.2%.

The relationship between the functional dimensions of the furniture and a user’s anthropometric dimensions is crucial for safety and functionality. The weight and dimensions of the user’s body significantly affect the functional dimensions of the furniture, especially for overweight users. This paper is focused on the concept of chair structural design, which is suitable for bariatric users, including the application of additional reinforcing structural components. Such components are expected to improve the stiffness and strength properties of the chair structure, and it provides the possibilities to a chair design with improved ergonomic parameters. To increase rigidity and reinforce the frame structure of a chair for obese users, the side stretchers, middle braces inserted under seat and armrests are used. The main goal of the different structural designs of chair frames is to minimize internal forces acting in the structural components of the chair. The finite element method (FEM) was used to determine the internal forces and stress-strain state in the structural elements of the chair, starting with the standard design of the chair frame and comparing different design variants. A synergistic effect is obtained, making the bariatric chair durable and ergonomic, without stigmatizing its users.

Sapele, pine, limba, iroko, beech, and oak wood species are important species used indoors and outdoors, as supplied by furniture companies. It is known that the color changes in wood material when exposed to the external environment. This is an important factor for the outdoor use of wood material. In this study, the color parameters of Scotch pine (Pinus sylvestris L.), oriental beech (Fagus orientalis L.), limba (Terminalia superba Engl. et Diels), sapele (Entandrophragma cylindricum), sessile oak (Quercus petraea L.), and iroko (Milicia excelsa) wood species, which are used in both indoor and outdoor woodworking industries in Van city, Turkey were investigated after exposing them to natural weather conditions for 9 months in outdoor conditions. Each type of wood exhibited a different color behavior in outdoor conditions. In sapele and limba wood species, b* and a* values increased and L* values decreased with increasing weathering time. It was observed that ∆E* increased with increasing time of exposure in all tree species. At the end of 9 months of weathering, the highest ∆E* value was determined in pine wood, followed by beech, sapele, limba, iroko, and oak wood species, respectively.

The study assessed CNC routing quality on maple and oak samples, using 90º V-Grooving router bits at various milling angles as function of grain orientation: 0°, 15°, 30°, 45°, 60°, 75°, 90°, and feed speeds of 3 and 6 m/min at spindle speed of 15,000 rpm. The routing quality was evaluated by roughness parameters for the V flank surfaces and by visual examination for the flanks’ edges. The change in the feed speed had no significant effect for the flanks surface quality of both species, but roughness values were considerable higher for maple samples at 90º and u=3 m/min (R_k = 23.7 µm compared to along the grain, R_k=9.83 µm for u=6 m/min) due to possible processing vibrations. The milling angle as function of grain orientation was significant in the case of oak, as the processing roughness increased with the cutting angle from 0° (R_k=11 to 13 µm) to 60°(R_k =28 to 30 µm). Fuzziness around the earlywood pores of oak was higher for the 6 m/min feed speed. A substantial increase in waviness coinciding with the annual growth areas was measured for crosscut oak samples (W_a = 34.0 µm, compared with W_a =7 .39 µm along the grain). The surface waviness of maple was not sensitive to the variation in the cutting angle or feed speed (W_a was around 3 to 4 µm). For the flank edges, the best visual option was found for cutting along the wood grain and the worst was for 60º, which caused biggest ruptures and especially for the 3 m/min feed speed, for both species.

Surface roughness and discoloration of thermally modified Scots pine (Pinus sylvestris L.), Kazdağı fir (Abies equi-trojani Asch. et Sint.), and Eastern beech (Fagus orientalis Lipsky) were evaluated. The surface roughness and discoloration of the samples sanded with 60, 80, and 120-grit grades were evaluated at temperature levels of 160, 180, 200, and 220 °C. Findings were subjected to multiple analysis of variance and Duncan’s homogeneity tests; using the SPSS package program, single, double, triple, and quadruple interactions were analyzed. The highest surface roughness values were found in Eastern beech samples with radial cross-section (12.4 µm) finished with 60-grit sandpaper. The lowest roughness value was found in Kazdagi fir samples that were heat-treated in 200 °C and processed with 120-grit sandpaper (2.03 µm). The lowest discoloration evaluation (∆E) value was found eastern beech samples 32.43, and highest ∆E values 46.86 found at Scots pine.

Antrodia cinnamomea is a valuable fungus. The 4-acetylantroquinonol B (4-AAQB) contained in it has strong anticancer activity. In this study, five kinds of herbs, burdock, wolfberry, coix seed, hawthorn, and tangerine peel were selected and processed into powders, aqueous extracts, and ethanolic extracts to investigate the effects on the production of 4-AAQB by A. cinnamomea. A combination strategy was conducted by adding burdock and tangerine peel aqueous extract. By this means, the production of 4-AAQB was improved to 54.5 mg/L, which was approximately 33-fold higher than the control. After analysis of components of the tangerine peel aqueous extract and the addition of the major components, vanillic acid, protocatechuic acid, and their analogs played an important role in the synthesis of 4-AAQB. It was demonstrated that the addition of Chinese herbs facilitated both cell growth of A. cinnamomea and 4-AAQB production, providing a feasible way to increase the yield of 4-AAQB.