Volume 12 Issue 2
- Researchpp 2367-2378Mazáň, A., Vančo, M., and Barcík, S. (2017). "Influence of technological parameters on tool durability during machining of juvenile wood," BioRes. 12(2), 2367-2378.AbstractArticlePDF
This work examined differences encountered when machining juvenile wood vs. mature wood. Difference in the blunting of the cutting tool when processing types of juvenile and mature wood from pine (Pinus sylvestris L.) and poplar (Populus tremula L.) were studied. The experimental model process included milling at various feed (2.5 and 15 m∙min-1) and cutting speeds (pine 20 m∙s-1, poplar 30 and 60 m.s-1), at various angle geometries (rake angle, cutting edge, and clearance angle). The blunting of cutting edge was measured after milling at 100, 300, and 500 meters on milling machine with the lower spindle. The results showed that milling of juvenile wood gives a longer technical lifetime for cutting instruments than milling of mature wood.
- Researchpp 2379-2393Theng, D., El Mansouri, N. E., Arbat, G., Ngo, B., Delgado-Aguilar, M., Pèlach, M. A., Fullana-i-Palmer, P., and Mutjé, P. (2017). "Fiberboards made from corn stalk thermomechanical pulp and kraft lignin as a green adhesive," BioRes. 12(2), 2379-2393.AbstractArticlePDF
The feasibility of incorporating purified kraft lignin, at different concentrations ranging from 5 to 29%, into fiberboards made from corn residues was studied. The lignin was obtained from black liquor, which is a residue of the paper industry. Corn stalk raw material and its thermomechanically produced fiber were characterized in terms of their chemical composition. The physical and mechanical properties of the resulting fiberboards were evaluated. The fiberboards produced following a wet process had good mechanical and water resistance properties that satisfied the requirements of the relevant standards. In addition, a Life Cycle Thinking (LCT) approach suggested that lignin-based fiberboards are environmentally preferable than those based on thermosetting resins.
- Researchpp 2394-2406Md Shah, A. U., Sultan, M. T. H., Cardona, F., Jawaid, M., Abu Talib, A. R., and Yidris, N. (2017). "Thermal analysis of bamboo fibre and its composites," BioRes. 12(2), 2394-2406.AbstractArticlePDFThermogravimetric analysis and differential scanning calorimetry were used to study the thermal degradation and thermal stability of bamboo powder and its composites (EP-BFC) in a nitrogen atmosphere. The thermal stability of EP-BFC decreased as the bamboo filler-loading increased. Compared with epoxy, bamboo powder had a lower thermal stability, which reduced the thermal stability for the higher filler-loading composites. The addition of glass fibre to the EP-BFC improved the thermal stability of the new hybrid composites. Both the hybrid and non-hybrid composites exhibited similar thermal-induced degradation profiles that had only one mass loss step. However, a noticeable difference between the percentage value of the degradation between both the hybrid and non-hybrid composites showed that the EP/G-BFC hybrids were more thermally stable than the non-hybrid EP-BFC. Different materials experienced different activities, which were clearly shown from the DSC analysis. Bamboo fibre and non-fully cured epoxy exhibit exothermic peaks, while fully cured epoxy exhibits an endothermic peak.
- Researchpp 2407-2420Tian, X., Wang, B., Wang, B., Li, J., and Chen, K. (2017). "Structural characterization of lignin isolated from wheat-straw during the alkali cooking process," BioRes. 12(2), 2407-2420.AbstractArticlePDFTo investigate the behavior of lignin during the alkali cooking process with different alkali doses, this work demonstrated the structural characteristics illustrated by spectroscopic analyses. Gel permutation chromatography (GPC) and nuclear magnetic resonance (NMR) indicated that the lignin was composed of typical structures for a grass, generally with S and G units and small amounts of H units. The main substructures present were β-O-4 aryl ether linkages, and there were lower amounts of β-β and β-5 linkages. Alkali treatment conditions had evident effects on the chemical structures and properties of lignin. Moreover, NMR indicated that alkali cooking caused lignin to depolymerize more easily with increasing severity and to condense.
- Researchpp 2421-2432Pekařová, S., Dvořáčková, M., Stloukal, P., Ingr, M., Šerá, J., and Koutny, M. (2017). "Quantitation of the inhibition effect of model compounds representing plant biomass degradation products on methane production," BioRes. 12(2), 2421-2432.AbstractArticlePDF
During the steam explosion pretreatment of plant biomass, degradation products are generated, and some of these have inhibitory activity against biogas production. The aim of this study was to investigate and quantify the effect of selected model inhibitory compounds on methane production. The results showed no significant inhibition of methane production by furfural at concentrations below 1 g/L. In addition, the microbial community was able to restore biogas production inhibited by this compound after a certain time. 5 hydroxymethylfurfural was evaluated as a more potent inhibitor, with a significant effect above 0.2 g/L. Both compounds were more effective inhibitors with cellulose as the carbon substrate, probably reflecting higher sensitivity of the cellulolytic step in biogas production. No significant inhibition was observed for the phenolic compounds tested, gallic and tannic acids, at concentrations of up to 2 g/L. Thus, the compounds investigated should not represent a problem for the biogas production involving steam explosion preprocessed plant biomass.
- Researchpp 2433-2451Dogu, D., Yilgor, N., Mantanis, G., and Tuncer, F. D. (2017). "Structural evaluation of a timber construction element originating from the Great Metéoron Monastery in Greece," BioRes. 12(2), 2433-2451.AbstractArticlePDFThis study identified the wood species and evaluated the degree of weathering and biological degradation of a historical timber construction element originating from the Great Metéoron monastery in Metéora, Greece. The wood material was provided from the interior side of a balcony that was fully covered with a roof and exposed to outdoor conditions for more than 400 years. The species was identified as Quercus spp. of the white oak group. In the timber element, the physical, morphological, and chemical changes were studied to assess the type and extent of degradation using light microscopy and Fourier transform infrared (FT-IR) spectroscopy. To examine the degree of biological degradation and weathering, the surface layer and inner parts of the specimen were studied separately and compared with a recent wood specimen of the same species. The FT-IR analysis revealed remarkable differences between the surface layer and the inner parts of the historical wooden element. Macroscopic and microscopic investigation indicated that multiple types of degradation caused by weathering, fungi, and insect attacks had occurred in the wood structure. It was finally concluded that the historical timber construction element was in better condition than was expected before the study.
- Researchpp 2452-2465Luo, L., Jin, Y., Li, M., Hu, L., Li, G., and Liu, Y. (2017). "Adsorption mechanism of anionic groups found in sulfonated mulberry stem chemi-mechanical pulp (SCMP) for removal of methylene blue dye," BioRes. 12(2), 2452-2465.AbstractArticlePDF
The anionic groups (AGs) present in mulberry stem sulfonated chemi-mechanical pulp (SCMP) were studied relative to the adsorption of methylene blue (MB) dye. Adsorption isotherm experiments were carried out for the unbleached pulp, and for pulp that had been subjected to hydrogen peroxide (H2O2) bleaching. AGs present in the pulps appeared to govern the adsorption of MB. MB adsorption kinetics were evaluated for the bleached pulp. The methylene blue adsorption by SCMP, made from mulberry stems, conformed to the Langmuir adsorption model, which is consistent with a monolayer adsorption process. The adsorption thermodynamics showed that the adsorption process was spontaneous and exothermic. A pseudo-second order kinetic model described the adsorption mechanism of MB by the SCMP made from mulberry stems.
- Researchpp 2466-2478Togay, A., Döngel, N., Söğütlü, C., Ergin, E., Uzel, M., and Güneş, S. (2017). "Determination of the modulus of elasticity of wooden construction elements reinforced with fiberglass wire mesh and aluminum wire mesh," BioRes. 12(2), 2466-2478.AbstractArticlePDF
Laminated composite wooden construction elements were produced with 7 layers of Scots pine (Pinus sylvestris L.). Fiberglass wire mesh and aluminum wire mesh, which were used as reinforcement materials, were pressed with polyvinyl acetate (PVAc) and polyurethane-type adhesives between each Scots pine layer. The highest bonding strength values were obtained from laminated control specimens produced with polyurethane adhesive without using support materials (4.98 N/mm2) and laminated control specimens made with polyurethane adhesive without using support materials (4.39 N/mm2), respectively. The modulus of elasticity in bending perpendicular to the glue line values of all the specimens except the laminated control specimens produced with polyurethane adhesive without using support materials (14800 N/mm2) were lower than solid wood (6720 N/mm2). In contrast, in the experiments for the modulus of elasticity parallel to the glue line, the variables (adhesive, intermediary layer materials) used for all experiments and specimens were effective factors. Although the modulus of elasticity in bending parallel to the glue line values of all samples were higher than solid wood (6720 N/mm2), the maximum value was obtained in the laminated control specimens produced with polyurethane adhesive without using support materials (17800 N/mm2).
- Researchpp 2479-2495Zakikhani, P., Zahari, R., bin Haji Hameed Sultan, M. T., and Majid, D. L. (2017). "Morphological, mechanical, and physical properties of four bamboo species," BioRes. 12(2), 2479-2495.AbstractArticlePDFBamboo among other plants has unique properties and massive variety. The properties of bamboo species vary between species and along their culms. The aim of this study was to investigate the characteristics of four bamboo species: Dendrocalamus pendulus (DP), Dendrocalamus asper (DA), Gigantochloa levis (GL), and Gigantochloa scortechinii (GS), and their three portions (bottom (B), middle (M), and top (T)). The number of fibre strands in vascular bundles and the single fibres extracted from every portion was studied. The distribution of fibres varied along the bamboo culms and between species. The DP species showed the highest water content and water absorption and the lowest mechanical properties. The DA species exhibited the best mechanical and physical properties. Moreover, the bottom portion of every species indicated the highest aspect ratio and tensile properties. The results indicated that before the application of bamboo culms in composite materials, the bamboo species should be characterized so that it can be utilised effectively as a renewable reinforcement in composites.
- Researchpp 2496-2506Lakshmi Veguta, V., Stevanic, J. S., Lindström, M., and Salmén, L. (2017). "Thermal and alkali stability of sodium dithionite studied using ATR-FTIR spectroscopy," BioRes. 12(2), 2496-2506.AbstractArticlePDF
Sodium dithionite (Na2S2O4) may have the potential to be used as a reducing agent for the stabilization of glucomannan in kraft cooking for increased pulp yield. However, due to the fact that dithionite decomposes under the conditions of kraft pulping, studies of the effects of dithionite in kraft pulping are non-conclusive; sometimes clearly showing an increased yield, and in other studies no effect at all. The specific conditions influencing dithionite degradation are also unclear. For that reason, this study was conducted to determine the thermal and chemical stability of sodium dithionite with respect to specific factors, such as the pH, temperature, heating time, and the concentration of sodium dithionite solution. The study was performed under anaerobic conditions using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The thermal and alkali stability of the sodium dithionite solution was shown to decrease with increasing temperature, heating time, and concentration of the solution at the alkaline conditions studied. The thermal stability decreased rapidly at weak alkalinity (pH 9) as well as in high alkalinity (pH 14), whereas the sodium dithionite was rather stable at moderate alkalinity (pH 11.5 to pH 13).