Volume 16 Issue 2

Bamboo-oriented strand board (BOSB) with superior physical properties can be used in the furniture industry to alleviate wood shortages. Two types of plug-in connectors were designed in this paper: a splint-type connector and V-type connector. By cantilever bending, corner tension, and compression tests of L-type corner joints of BOSB and wood-oriented strand board (WOSB), the connection performance of the new connectors and six typical connectors was compared. The new connectors function like clamps, do not require that a screw or bolt pass into or through the board, and can be assembled repeatedly. The V-type connectors were more suitable for BOSB, and the joints exhibited the highest ultimate bending moment values (133.9 N·m, 86.8 N·m, 117.7 N·m). The splint connectors were more suitable for WOSB and their ultimate bending moment values (57.1 N·m, 45.3 N·m, 61.3 N·m) were greater than the joints fixed by V-type connectors (50.4 N·m, 35.4 N·m, 46.1 N·m). The results revealed that the connector performance affects the joint strength and that different plates were suitable for different connectors. A joint failure analysis revealed two simple failure modes for the two new connectors.

The demand for timber resources in the building industry has been increasing. Plantation Eucalyptus nitens is of interest because of its sustainable supply and potential for structural applications. However, few design standards cover strength values of plantation eucalypt timber, especially flexural failure below and above the fibre saturation point, which is an important mechanism of failure in bending members used in the building industry. Static bending tests were undertaken using a universal testing machine to examine nonlinear bending behaviour of 130 fibre managed E. nitens small clear wood samples at low and high moisture contents (MC). The mean bending modulus of rupture (MOR) was 80.7 MPa for low MC and 59.0 MPa for high MC. The high MC samples exhibited larger displacements at low ultimate loads, while the low MC samples showed abrupt failures at relatively small displacements with high ultimate loads. The design characteristic values for low and high MC E. nitens were 68.5 MPa and 39.8 MPa, respectively. This research demonstrates that fibre managed E. nitens timber is a promising timber for structural applications, especially when exposed to water, as the MOR reduction of E. nitens timber above FSP is relatively lower than those of P. radiata, which is a traditional construction material.

The effects of nitrogen in the medium on the production of mycelial biomass, extracellular polysaccharides (EPS), and intracellular polysaccharides (IPS) was investigated in submerged cultures of Grifola frondosa. In addition, the effects on pellet morphology were examined. The maximum production levels of mycelial biomass (2.32 g/L), EPS (1.58 g/L), and IPS (29.1 mg/L) were obtained when the nitrogen sources in the medium were yeast extract, malt extract, and peptone, respectively. Using yeast extract as the nitrogen source yielded the maximum mycelial biomass, and morphological characterization revealed a composition of 47% large pellets (fraction L), 20% small pellets (fraction S), and 33% adhesive mycelia (fraction A). The maximum circularity value and the minimum roughness value of the pellets were observed using yeast extract cultures. Both the compactness (0.53) and circularity (0.15) of the pellets were the lowest among the seven types of nitrogen sources, but the roughness (2.86) was the highest in malt extract, which was the nitrogen source that resulted in maximum polysaccharide production. The results revealed that the production levels of mycelial biomass, EPS, and IPS of G. frondosa were associated with changes in pellet morphology due to the source of nitrogen in the medium.

Barks of Tachigali guianensis and Tachigali glauca, from the Brazilian Amazon rainforest, were studied regarding anatomy and chemical composition. The barks were similar, with a narrow rhytidome, a ring of sclerified cells below the periderm, a widely dilated and sclerified nonconducting phloem, septate crystal strands, and extensive phenolic deposits in cells. Differences between the species were mainly in the sclerenchyma. Proportions of cell types in the T. guianensis and T. glauca barks were, respectively: 27.8% and 28.3% axial parenchyma, 15.6% and 15.1% sieve tube elements, 11.6% and 13.4% radial parenchyma, 15.6% and 8.7% sclereids, and 30.5% and 34.5% fibers. Chemical analysis showed that the T. guianensis and T. glauca barks included, respectively: 18.0% and 15.3% extractives, 1.8% and 1.0% suberin, 26.8% and 27.9% lignin, and 3.5% and 4.5% ash. The predominant polysaccharides were glucose (72.8% and 82.8% of total neutral sugars) and xylose (17.9% and 11.6%). Ethanol-water extracts were high in phenolics (total phenolics of 441.0 mg gallic acid equivalents (GAE) / g extract and 641.7 mg GAE / g extract), with moderate antioxidant activities (IC50 values of 7.3 µg extract / mL and 5.6 µg extract / mL). Tachigali guianensis bark and, particularly, T. glauca bark may be sources of phenolic compounds.

This study created biomass-pellet fuel with reduced ash content from agarwood waste mixed with empty palm bunches (ACW+EPB), and from agarwood waste with rubber wood sawdust (ACW+RWS), utilizing the low ash value of the agarwood waste. The tested blends had a 1:1 ratio of agarwood waste and empty palm bunches, and a 1:3 ratio of agarwood waste and rubber wood sawdust. Comparisons were also conducted relative to Korean (Grade 4) (2014) and ENplus B (2014) commercial pellet standards. Before pressure molding, the mixture components were dried and ground in a pelletizing device with a motor power of 7.5 kW (380 V, 50 Hz), yielding 100 to 150 kg/h without added adhesive. The test results showed that ACW ash content decreased in the RWS hybrid, yet increased in the EPB mixture. The attributes of ash content, moisture content, and heating value of ACW+RWS satisfied ENplus B (2014) and Korean (Grade 4) (2014) standards at 1.70%, 4.50%, and 4,536 kcal/kg. The ACW+EPB also satisfied the Korean (Grade 4) standard at 4.20%, 6.50%, and 4,220 kcal/kg. Thus, the biomass pellets from the mixture of agarwood waste and rubber wood sawdust and that of agarwood waste and empty palm bunches were of suitable quality for commercial purposes.

NaOH-impregnation with catalyst steam explosion was found to be an efficient pretreatment method for oil palm empty fruit bunch (OPEFB) as a substrate for oil production by Naganishia cerealis IN1S2.5. Cellulase hydrolysis of the pretreated OPEFB yielded glucose at 0.364 g/g. Investigation of N. cerealis IN1S2.5 oil production in the OPEFB hydrolysate revealed a maximum oil yield (2.46 g/L) when the C/P molar ratio of the OPEFB hydrolysate was adjusted to 25.71, supplemented with Ca2+ and Zn2+, and set to pH 4. The N. cerealis IN1S2.5 oil was comprised of oleic (37.6%), palmitic (36.2%), and steric (17.9%) acids, all (w/w), as the major fatty acids. Predicted properties of the produced biodiesel indicated the potential of N. cerealis IN1S2.5 oil as a biodiesel feedstock.

Compost and Arbuscular mycorrhizal fungi are environmentally sustainable and low-cost materials that can benefit tropical soils with high phosphorus fixation and low organic matter content. This study investigated the effects of Arbuscular mycorrhizal fungi (AMF) and compost on the growth and nutrient uptake efficiency of sugarcane (Saccharum officinarum) seedlings. The experimental design was a completely randomized factorial design, where factor A (n = 5) was the compost doses (0, 15, 30, 60 and 120 t ha-1) and B (n = 3) the AMF inoculum (Rhizophagus clarus, Gigaspora margarita, and non-inoculated). At 30 and 90 d, seedlings’ diameter and height were measured. Mycorrhizal colonization rate, biomass production, nutrient uptake (P and N), and mycorrhizal dependency were assessed at the end of the experiment. The AMF and compost doses affected the colonization rate, initial growth, biomass production, and nutrient uptake of sugarcane seedlings. Overall, the AMF benefited plant growth at lower doses of compost. R. clarus had a higher impact on the shoot diameter of sugarcane seedlings. Mycorrhizal colonization increased with compost addition only in seedlings inoculated with G. margarita. There was no clear trend among AMF treatments for nutrient uptake. In general, sugarcane seedlings dependency on mycorrhizal condition to produce growth was higher at lower compost doses.

The laccase producing abilities of four Basidiomycete fungi species were compared using solid-state fermentation using four different lignocellulosic residues. The biosynthetic potential of the Basidiomycetes was highly dependent on the type of fungi. In general, the laccase secreting ability of Cerrena unicolor Han 849 was greater than Lenzites betulinus Han 851, Stropharia rugosoannulata Han 1321, and Auricularia heimuer Han 1333. The maximum laccase production of C. unicolor Han 849 was approximately 11.25, 122.26, and 15.27 times higher than L. betulinus Han 851, S. rugosoannulata Han 1321 and A. heimuer Han 1333, respectively. Different species of fungi had a preference in lignocellulosic residues. The presence of Firmiana platanifolia was conducive to secreting laccase via C. unicolor Han 849 during solid-state fermentation. A continuous and stable laccase production via C. unicolor Han 849 was an obvious advantage of solid-state fermentation with any of the four lignocellulosic residues used. The maximum laccase production of C. unicolor Han 849 using Firmiana platanifolia was approximately 2.12, 1.68, and 6.13 times higher than Populus beijingensis, Sorghum bicolor, and Oryza sativa, respectively. These findings will be helpful for developing new productivity strains in industrial applications and selecting suitable lignocellulosic residues for laccase production.

The pin-penetration device is a minimally destructive instrument that is widely used to estimate the physical properties of wood, e.g., density, with advantages such as reduced testing times, low costs, and fewer defects induced in the wood being tested. In this study, such a device was used on 25 Indonesian hardwood species with a strength class (SC) distribution from SC II to IV (according to the Indonesian classification of wood SCs). Tests were conducted on three different orthogonal planes, i.e., cross-sectional, radial, and tangential planes. The wood density ranged from 0.28 to 0.88 g/cm3, and the specific gravity was 0.25 to 0.76. The cross-sectional plane penetration depth of the wood was significantly greater than that of either the radial or tangential plane, whereas the pin penetration values of the radial and tangential planes were not significantly different. A prediction model for predicting the density and specific gravity of wood via pin penetration showed a significant regression. Thus, the use of a pin-penetration device was found to be suitable for estimating wood density and specific gravity in a range of SCs of tropical wood species regardless of species.

Tree acoustic tomography is a widely used device supported method for tree stability assessment. In this work, the results of the three most commonly used devices for acoustic tomography of standing trees (ARBOTOM®, ArborSonic®, and PiCUS®) were compared on selected individuals of sessile oak in Brno, Czech Republic. According to the statistical analysis, there was a significant difference between values measured by the PiCUS® acoustic tomograph and those measured by both the ARBOTOM and ArborSonic® acoustic tomographs. Based on the measured data, velocities measured by PiCUS® were considerably lower than those recorded by the other acoustic tomographs (ARBOTOM® and ARBORSONIC®). Measured radial and tangential velocities differed from each other. In data obtained from the defective cross-sections, this difference was attenuated. Image reconstructions (tomograms) from the acoustic tomographs differed from each other. Complex shapes of defects in standing trees can significantly influence acoustic tomography results. According to the statistical analysis, there was no significant relationship between sound velocity and density, while there was a relatively strong positive correlation between sound velocity and moisture content.