NC State
  • Editorialpp 3755-3756Finkbeiner, M. (2014). "Indirect land use change - Science or mission?," BioRes. 9(3), 3755-3756.AbstractPDF
    The current discussions of indirect land use change (iLUC) and the greenhouse gas (GHG) reduction potential of bioresources have turned into a rather controversial debate. The scientific robustness and consistency of current iLUC models and data are at least unclear. However, representatives of the scientific community still dare to provide straightforward political advice in their papers – way beyond the fact-based ‘proof’ of their data and on a level that is usually not accepted by scientific journals. But the actual task and challenge for the scientific community is to determine the environmental performance of bioresources as objectively and fact-based as possible – with a clear and sober focus on integrity and soundness, not sense of mission.
  • Editorialpp 3757-3758Shen, J., Su, W., Yang, D., and Qian, X. (2014). "English-assisted teaching pertaining to pulp and paper in Chinese universities: An undergraduate perspective," BioRes. 9(3), 3757-3758.AbstractPDF
    Currently, about 20 universities in China offer undergraduate courses related to pulp and paper. This large number is congruent with the rapid development of the Chinese pulp and paper industry in the past several decades. In the context of ever-increasing internationalization and global cooperation, English-assisted teaching in Chinese universities has much potential. The wide-spread implementation of English-assisted teaching would promote the career development of students and help foster the advancement of the Chinese pulp and paper industry.
  • Editorialpp 3759-3760Hubbe, M. A. (2014). "Zipping backwards the other way - Yet another unique aspect of cellulose," BioRes. 9(3), 3759-3760.AbstractPDF
    Readers of this journal may be keenly aware of cellulose’s remarkable attributes, such as high stiffness, insolubility in just about everything, resistance to enzymatic attack, dimensional stability in the lengthwise direction, and toughness associated with the alternating crystalline zones and less organized regions. But if you dissolve cellulose and then allow it to recrystallize, the resulting crystals are at the same time radically different, and yet remarkably similar in most respects to the native form. Exactly half of the macromolecules in regenerated cellulose have been reversed 180 degrees in their direction. The behavior of dropped pencils can help explain why this happens.
  • Researchpp 3761-3778Prokkola, H., Kuokkanen, M., Kuokkanen, T., and Lassi, U. (2014). "Chemical study of wood chips drying: Biodegradation of organic pollutants in condensate waters from the drying process," BioRes. 9(3), 3761-3778.AbstractPDF
    In 2008, the European Union Commission put forward a proposal for a new directive on renewable forms of energy. Each of the member states should increase its share of renewable energies in an effort to boost the total share of the EU from the current 8.5% to 20% by 2020. The level of renewable energy in Finland was 28.5% in 2005, and the national target share of renewable energy by 2020 is 38%. To assist in reaching this goal, one solution is to further develop drying techniques of biomasses and utilization of untapped biomasses, because in Finland, up to 20 million tons of waste wood biomass per year are left unused during forestry operations. In this study the drying of biomasses and the condensate, including biodegradation of organic pollutants, is examined. The cost-efficiency and energy-efficiency of wood chips combustion can be increased by drying the wood to optimize moisture content before being utilized in different applications. However, the removal of moisture is the most expensive unit process in combustion. Studied wood species were pine (Pinus sylvestris), spruce (Picea abies), aspen (Populus tremula) and two birch species (Betula pendula and Betula pubescens). The biodegradation degrees of studied organic pollutants in condensing waters were between 25% and 61%. Furthermore, the biodegradation of organic compounds in condensing waters showed that at least the studied condensates can be safely disposed via municipal wastewater treatment plant (WWTP).
  • Researchpp 3779-3791Guo, X., Ekevad, M., Grönlund, A., Marklund, B., and Cao, P. (2014). "Tool wear and machined surface roughness during wood flour/polyethylene composite peripheral up-milling using cemented tungsten carbide tools," BioRes. 9(3), 3779-3791.AbstractPDF
    The effect of sharpness angle on tool wear and the effect of tool wear on machined surface roughness were investigated in wood flour/polyethylene composite (WFPEC) peripheral up-milling using cemented tungsten carbide (TC) tools. It was shown that nose width and edge recession increased with increasing feeding length. During the milling process, the wear of the nose width was smallest for the tool with a sharpness angle of 45°, followed by tools with sharpness angles of 55° and 65°. The wear of edge recession was highest for the tool with a sharpness angle of 45°, followed by tools with sharpness angles of 55° and 65°. The nose width increased with increasing sharpness angle, the edge recession decreased with increasing sharpness angle, and the machined surface roughness increased with increasing sharpness angle after a feeding length of 40 m. The nose width had a positive effect on the machined surface roughness, and the machined surface roughness increased with increasing nose width. The edge recession had little effect on the machined surface roughness. The clearance face roughness of the worn tool increased with increasing sharpness angle. The analysis of the SEM micrographs and EDS of the clearance face of the worn tool showed that the wear mechanisms of the cemented tungsten carbide tool were oxidation and abrasion in the range tested during cutting. Thus, a slight wear of the edge recession is gained in exchange for a lower machined surface roughness by decreasing the sharpness angle.
  • Researchpp 3792-3804Wang, M. Y., Lin, C. P., Li, Y. T., and Ma, H. K. (2014). "Utilization of fire dynamics simulator model to study rice husk gasification in fixed-bed gasifier," BioRes. 9(3), 3792-3804.AbstractPDF
    Computational Fluid Dynamic (CFD) modeling applications of the biomass gasification process help to optimize the gasifier. This study aims to investigate the impact of several physical parameters on the behavior of gasification in a fixed-bed downdraft gasifier. To that end, the study presents a comparison of the results computed using the Fire Dynamics Simulator (FDS) model with experimental results of biomass gasification. Therefore, different sets of simulations and experiments have been performed to examine the effects of initial moisture content, equivalence ratio, high heating value (HHV), and cold gas efficiency (CGE). At the optimum operation, the equivalence rate is 0.3, the HHV can reach 5.71 MJ/m3, and the produced hydrogen concentration is 26.53 vol%. For an initial moisture content of 11.18%, the measured CGE is 66.85%, which is within the range of 65.07% to 70.44%. In general, the initial moisture content of the rice husks is suggested to be below 18%. The overall results indicate that the FDS model can effectively simulate and analyze gasification performance inside the gasifier, and the performance of an improved downdraft gasifier system (IDGS) is improved by higher cold gas efficiency.
  • Researchpp 3805-3824Thilagavathy, P., Santhi, T. (2014). "Studies on the removal of Cu(II) from aqueous solutions using modified Acacia nilotica leaf," BioRes. 9(3), 3805-3824.AbstractPDF
    In this work, sustainable and biodegradable Acacia nilotica leaf (AN) was chemically modified to remove Cu(II) from aqueous solutions, which is considered a versatile approach to clean contaminated aquatic environments. Zinc chloride-modified Acacia nilotica leaf (ZAN) was characterized by scanning electron microscopy (SEM) and other physico-chemical parameters like pHZPC. The aim was to assess the efficiency and mechanism of adsorption on Acacia nilotica via isotherm models (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Harkin-Jura, and Frenkel-Halsey-Hill), kinetic models, and thermodynamic parameters. To optimize the removal efficiency, parameters such as effect of initial concentration, effect of pH, dosage, initial concentration, and contact time were studied by batch and column methods. Desorption studies illustrated that about 73% of the metal ions could be removed using 0.2N HCl. The results of the present investigation indicated that ZAN has a high potential for the removal of Cu(II) from aqueous solutions, and the resultant data can serve as a base line for designing treatment plants on an industrial scale.
  • Researchpp 3825-3834Peng, L., Li, H., Long, X., Chen, K., and Chen, H. (2014). "Facile and efficient conversion of furfuryl alcohol into n-butyl levulinate catalyzed by extremely low acid concentration," BioRes. 9(3), 3825-3834.AbstractPDF
    Alkyl levulinates have been identified as promising chemicals with various industrial applications. Here, a catalytic process for the synthesis in an n-butanol medium of n-butyl levulinate via the alcoholysis of biomass-derived furfuryl alcohol was performed using an extremely low concentration of sulfuric acid (≤ 0.01 M) as the catalyst. A study was conducted that was designed to optimize the process variables, which include acid concentration, reaction temperature, initial substrate concentration, and water content, as a function of time. The optimum conditions resulted in a furfuryl alcohol conversion of nearly 100% and a high n-butyl levulinate yield of up to 97%, which was confirmed by isolated yield. An advantage of this catalyst system is that negligible undesired oligomeric products were formed from the side reaction for the polymerization of furfuryl alcohol, the catalyst cost is low, and less solid waste was discharged from the neutralization of spent acid. Overall, this catalytic strategy is a facile, efficient, and economical approach to the conversion of biomass-derived furfuryl alcohol into alkyl levulinates.
  • Researchpp 3835-3845Salem, M. Z. M., Ali, H. M., and Mansour, M. M. (2014). "Fatty acid methyl esters from air-dried wood, bark, and leaves of Brachychiton diversifolius R. Br: Antibacterial, antifungal, and antioxidant activities," BioRes. 9(3), 3835-3845.AbstractPDF
    The composition of methylated fatty acids from wood, bark, and leaves of Brachychiton diversifolius was analyzed for the first time using gas chromatography (GC). The results indicated that the major methyl ester of fatty acids found in wood, bark, and leaves were: myristic acid (8.32%), palmitic acid (15.66%), and palmitic acid (9.95%), respectively. In accordance to the biological effects of fatty acid fraction, they were moderately effective against Bacillus subtilis and Sarcina lutea, but they did not show any effect against the growth of Staphylococcus aureus and Pectobacterium carotovorum at a concentration of 2000 μg/mL. The maximum percentages of inhibition of fungal mycelial growth against Penicillium selerotigenum (60.35%), Paecilomyces variotii (70.80%), and Aspergillus niger (70.50%) were shown by the fatty acids from leaves, bark, and bark, respectively. The total antioxidant activity (TAA %) of fatty acids from wood, bark, and leaves, were 40±3.13%, 80±5.14%, and 60±4.50%, respectively. In accordance to the results, the different parts of B. diversifolius could provide important components, such as fatty acids with antimicrobial and antioxidant activities for future studies or uses.
  • Researchpp 3846-3856Tu, D., Su, X., Zhang, T., Fan, W., and Zhou, Q. (2014). "Thermo-mechanical densification of Populus tomentosa var. tomentosa with low moisture content," BioRes. 9(3), 3846-3856.AbstractPDF
    This study used thermo-mechanical densification technology to compress low-moisture content (3~5%) rapid-growth Populus tomentosa var. tomentosa trees to produce specimens with a low-compression ratio (small volume loss) and a uniform density profile and desirable properties. Furthermore, the densified specimens were subjected to post-heat treatment at 180, 190, and 200 °C for 2, 3, and 4 h, respectively. Microscopic examination was performed to observe the changes that occurred in the wood vessels after densification. To determine the influence of post-heat treatment on the set recovery, the specimens were subjected to eight cycles of soaking and drying in 20 °C water and two cycles in boiling water. The density profile tendencies of the densified specimens were in accord with undensified specimens. Microscopic observation revealed that the deformations present in the densified wood resulted from the viscous buckling of cell walls without fracture. The volume of the void areas in the specimens decreased uniformly. Post-heat treatment can decrease compressive deformation, especially when applied at 200 °C for 4 h. After two boiling water cycles of soaking and drying, the densified wood still had a certain set recovery. Therefore, densified wood should be used sparingly in high temperature and high humidity environments.
  • Researchpp 3857-3868Wu, P., Ma, Y., Chen, Y., Zhang, Y., and Wang, H. (2014). "Vibration-assisted compaction of biomass," BioRes. 9(3), 3857-3868.AbstractPDF
    The biomass extrusion process for making biomass briquettes or logs normally requires large amounts of energy to overcome the springback of the material and friction with the die surface. Also, the products readily expand and disintegrate because of the retention of internal stresses. In this study, tests on vibration-assisted compaction of biomass were performed as a method to reduce the energy requirement and to improve product quality. An experimental set-up was designed and manufactured by which vibration-assisted compaction was exerted on a die surface. Tests on compaction to form upgraded biomass logs with and without the assistance of vibration were conducted and compared. The results showed that the vibration applied on a die surface can reduce the compression energy requirements and improve product quality.
  • Researchpp 3869-3882Wang, Z., Wang, Z., Wang, B. J., Wang, Y., Liu, B., Rao, X., Wei, P., and Yang. Y. (2014). "Dynamic testing and evaluation of modulus of elasticity (MOE) of SPF dimensional lumberAbstractPDF
    The key objective of this work was to develop a cost-effective and reliable non-destructive testing (NDT) method to measure lumber modulus of elasticity (MOE). Test samples comprised 300 pieces of randomly selected imported Canadian 2”×6” SPF (Spruce - lodgepole Pine - alpine Fir) dimensional lumber. This work first adopted a modal test to achieve a free suspension for a subsequent vibration test. Then, the first-order natural frequency of 300 SPF dimensional lumber specimens was measured by the transient excitation frequency method, based on which MOE was then calculated. The results were also validated by a stress wave method using a Hitman tool. The measured lumber MOE data were further fitted using a Weibull distribution. The results showed that the MOE of SPF dimensional lumber followed either a three-parameter Weibull distribution or a normal distribution. It was estimated that the probability that the MOE of this SPF dimensional lumber was less than 8,000 MPa was about 13.8% and 13.6%, respectively, using the above two distributions.
  • Researchpp 3883-3900Togay, A., and Ergin, E. (2014). "Determination of some physical attributes for wooden construction elements strengthened with woven wire fiberglass," BioRes. 9(3), 3883-3900.AbstractPDF
    This study designed composite wooden construction elements strengthened with woven wire fiberglass netting and determined the technical attributes. Scots pine (Pinus sylvestris L.) was used in wooden layers, and woven wire fiberglass netting was used in intermediate layers. Layers were pressed with polyvinyl acetate (PVAc) D3 and Desmodur-VTKA adhesives to form 7 solid 13-layer laminated composite specimens. Experiments on 95 specimens determined density, bonding strength, bending resistance, and compression strength; solid and solid laminated wooden materials were tested and compared. BS EN 204 and BS EN 205 standards were complied with for bonding strength tests, TS 5497 EN 408 was used for densities, and TS 549 EN 408 was followed for bending resistance and compressive strength. Most factors, except for intermediate layer material in compressive strength and bending resistance tests perpendicular to the glue line, did not cause significant differences. Variables (adhesive, intermediate layer material) used for determining bending strength parallel to the glue line were effective. Polyurethane adhesive increased resistance to bending parallel to the glue line. These composite wooden construction elements supported with woven wire fiberglass netting could be advantageous for applications that require high bending resistance perpendicular to the glue line. However, these composites do not hold a compressive strength advantage.
  • Researchpp 3901-3908Zhou, Y., Min, D. Y., Wang, Z., Yang, Y., Kuga, S. (2014). "Cellulose esterification with octanoyl chloride and its application to films and aerogels," BioRes. 9(3), 3901-3908.AbstractPDF
    Homogeneous esterification of cellulose with octanoyl chloride (a long-chain fatty acid) was investigated in lithium chloride/N,N-dimethyl acetamide (LiCl/DMAc) medium. Cellulose was readily esterified by the octanoyl chloride, as shown by 1H NMR analysis. The effects of the ratio of octanoyl chloride to cellulose hydroxyl groups, the reaction temperature, and the reaction time on the yield and degrees of substitution (DS) of cellulose esters (CEs) were investigated. CEs with high DS (2.2) were achieved after 8 h at 100 °C with a 1.6 to 1.8 of molar ratio of octanoyl chloride to cellulose hydroxyl groups. Furthermore, hydrophobic, fully transparent CE films and aerogels were prepared using CE tetrahydrofuran (THF) solutions. The CE aerogels exhibited high porosity and were formed with evenly distributed porosity, as revealed by scanning electron microscopy (SEM).
  • Researchpp 3909-3918Ma, M. G., Deng, F., Yao, K., and, Tian, C. H. (2014). "Microwave-assisted synthesis and characterization of CaCO3 particles-filled wood powder nanocomposites," BioRes. 9(3), 3909-3918.AbstractPDF
    The purpose of this study was to develop a rapid and green method for the synthesis of biomass-based materials. A microwave-assisted method was used for the preparation of CaCO3 particles-filled wood powder nanocomposites, which involve natural cellulosic materials, CaCO3, and microwave heating. Dewaxed wood powder was pretreated in the NaOH/urea solution. The urea acts as part of the CO32- source and provides a basic condition for the synthesis of CaCO3. The influences of reaction parameters such as the heating time and the addition of (NH4)2SO4 on the products were investigated by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The experimental results demonstrated that the heating time had an effect on the crystallinity and morphology of the nanocomposites. In addition, the presence of (NH4)2SO4 played an important role in the morphology and dispersion of CaCO3 in the nanocomposites.
  • Researchpp 3919-3938Trischler, J., and Sandberg, D. (2014). "Monocotyledons in particleboard production: Adhesives, additives, and surface modification of reed canary grass," BioRes. 9(3), 3919-3938.AbstractPDF
    As a supplier to the furniture industry, the particleboard industry is searching for opportunities to reduce costs, weight, and formaldehyde emissions. One such opportunity is to use monocotyledons such as straw and hemp, as well as grasses like reed canary grass. A major problem when using reed canary grass or other monocotyledons in combination with wood is the difference in their surface properties, leading to poor reactivity and wettability with adhesives such as melamine urea formaldehyde. To this end, either the surface of the particles must be modified in some way, or different adhesives must be used. The purpose of this paper is to present adhesives, surfactants, coupling agents, and pre-treatment methods that can be used in combination with monocotyledons to improve compatibility with wood. Some of the methods have been tested on reed canary grass. The results show a wide range of strength values for the joint between wood and untreated or pre-treated reed canary grass glued with different adhesives, with and without a surfactant and a coupling agent. Isocyanate-based adhesives provided relatively strong bonds, and polyvinyl acetate, acryl, and epoxy adhesives were also effective. The most effective method was pre-treatment followed by adhesives in combination with a coupling agent.
  • Researchpp 3939-3954Ma, Y., Wang, Q., Sun, X., Wang, X., Su, W., and Song, N. (2014). "A study on recycling of spent mushroom substrate to prepare chars and activated carbon," BioRes. 9(3), 3939-3954.AbstractPDF
    (SMS) via pyrolysis. It was found that as the pyrolysis temperature increased from 400 to 700 °C, the char yield decreased from 45.10 to 33.79 wt.% and the higher heating value increased from 17.32 to 22.72 MJ/kg. The largest BET surface area (13 m2/g) was created at 500 °C. Hydrogen atoms were continuously lost during pyrolysis, whereas oxygen atoms were difficult to eliminate. Whewellite, calcite, lime, and quartz were the minerals in the chars, and their forms and crystallinity changed with changing pyrolysis temperature. Activated carbon with a BET surface area of 1023 m2/g and a total pore volume of 0.595 cm3/g was obtained from the char prepared at 500 °C. Its characteristics were studied by N2-adsorption, Fourier transform infrared spectroscopy ( ), and X-ray diffraction (XRD). The pyrolysis and KOH-activation processes were investigated by thermogravimetric analysis (TGA). The results showed that the pyrolysis of SMS occurred primarily between 217 and 375 °C and that the energies needed for the pyrolysis reactions were relatively low due to the prior mushroom cultivation. Furthermore, lignin was incompletely decomposed in the char prepared at 500 °C, and KOH suppressed tar evolution and reduced the energy needed to decompose the residual lignin during activation.
  • Researchpp 3955-3967Song, J., Yang, W., Fu, F., and Zhang, Y. (2014). "The effect of graphite on the water uptake, mechanical properties, morphology, and EMI shielding effectiveness of HDPE/bamboo flour composites," BioRes. 9(3), 3955-3967.AbstractPDF
    This goal of this work was to study the effect of graphite on the water uptake, mechanical properties, morphology, and electromagnetic interference shielding effectiveness (EMI SE) of HDPE/Bamboo flour composites using the material mechanical testing machine, scanning electron microscopy (SEM), and EMI shielding apparatus. The water uptake of the composites was improved by graphite. Compared with the neat HDPE/bamboo composites, the flexural strength of the graphite-filled composites showed a small decrease, but the flexural modulus was enhanced greatly, indicating that graphite could effectively elevate the stiffness of the composites. An obvious result was that the toughness of composites was improved considerably by the graphite. The notched impact strength of the composites was increased from 5.18 to 9.0 KJ/m2 as graphite content was increased from 0 to 40 %. A large amount of graphite would increase the conductivity property and the EMI SE. The HDPE/bamboo composite with 40% of graphite exhibited electrical resistivity of 31.2 and the EMI SE of 20 dB in the frequency range of 30 - 3000 MHz.
  • Researchpp 3968-3976Wang, W., Yuan, T., and Cui, B. (2014). "Biological pretreatment with white rot fungi and their co-culture to overcome lignocellulosic recalcitrance for improved enzymatic digestion," BioRes. 9(3), 3968-3976.AbstractPDF
    Three white rot fungi (Lenzites betulinus, Trametes orientalis, and Trametes velutina) as well as their respective paired cultures were used to pretreat Populus tomentosa for enhanced lignocellulosic degradation and enzymatic hydrolysis. Hemicellulose and cellulose were slightly degraded, while a maximum lignin degradation of 58% was caused by T. velutina during the 12-week cultivation. was as high as 41%, which was in line with the lignin loss at 2.2 times the control sample. Overall, the monocultures of white-rot fungi exhibited better degradation and saccharification of woody biomass than their co-culture. This can be attributed to the partial removal of lignin and hemicellulose, with an associated increase of cellulose accessibility to enzymes.
  • Researchpp 3977-3992Pérez-López, H., Gómez-Merino, F. C., Trejo-Téllez, L. I., García-Morales, S., and Rivera-Olivares , L. Y. (2014). "Agricultural lignocellulosic waste and volcanic rock combinations differentially affect seed germination and growth of pepper (Capsicum annuum L.)," BioRes. 9(3), 3977-3992.AbstractPDF
    The effect of three substrates derived from combining agricultural lignocellulosic residues and a volcanic rock called tezontle (40/60; v/v) was tested on the germination and biomass production of five varieties of pepper (Capsicum annuum L.) grown under greenhouse conditions. The three substrates consisted of sugarcane bagasse and tezontle (SBTZ), coffee husk and tezontle (CHTZ), and filter cake from the clarification of sugarcane juice and tezontle (FCTZ), whereas the pepper varieties tested were Sven F1, Sympathy F1, Zidenka F1, Yolo Wonder, and California. Physical analyses of the substrates indicated that they had suitable properties, except for the percentage of readily available water, which was low in all the substrates. With regard to the chemical analyses, the best substrate was FCTZ. The highest germination percentage and the shortest time in which maximum germination was reached were also both found with the FCTZ substrate. Additionally, the greatest plant height and the highest shoot and biomass production were also recorded with the FCTZ substrate. In terms of varieties, those that responded best to the substrates were Sven F1, Sympathy F1, and Zidenka F1.
  • Researchpp 3993-4005Li, L., Zhou, W., Wu, H., Yu, Y., Liu, F., and Zhu, D. (2014). "Relationship between crystallinity index and enzymatic hydrolysis performance of celluloses separated from aquatic and terrestrial plant materials," BioRes. 9(3), 3993-4005.AbstractPDF
    Hydrolysis experiments of five cellulose samples (separated from two aquatic plants and three terrestrial plants, respectively) were conducted at various cellulase loadings (7 to 200 FPU/g cellulose). No obvious correlation was found between CrI and hydrolysis performance at low enzyme loadings (e.g. 7 and 28 FPU/g cellulose), as the hydrolysis was controlled by enzyme availability and the differences in cellulose structure were unimportant. At a sufficiently high enzyme loading (e.g. 200 FPU/g cellulose), the yield of reducing sugar was linearly proportional to the CrI value. Therefore, to establish such a correlation between cellulose structure and hydrolysis performance, hydrolysis experiments must be conducted under the conditions where enzyme availability is not a limiting factor. It was found that celluloses from sugarcane bagasse and water hyacinth have low CrI, achieve high sugar yields, exhibit fast reactions during enzymatic hydrolysis at low enzyme loadings, and can potentially be good feedstocks for bio-ethanol production.
  • Researchpp 4006-4013Duan, J., Jiang, J., Han, C., Yang, J., Liu, L., and Li, J. (2014). "The study of intermolecular inclusion in cellulose physical gels," BioRes. 9(3), 4006-4013.AbstractPDF
    In this study, cellulose possessing β-cyclodextrin (β-CD) is employed as a host molecule, and cellulose possessing ferrocene (Fc) is used as a guest polymer. The properties due to the host-guest interactions are presented. The results show that β-CD-cellulose and Fc-cellulose can form inclusion complexes wherein hydrophobic interaction caused by β-CD-cellulose and Fc-cellulose significantly affect the performance of the cellulose gel. A physical gel based on cellulose that can autonomously heal between cut surfaces after 24 h was formed under mild conditions. Moreover, ferrocene redox status affects the hydrophobic interaction, such that the hydrophobic interaction can strengthen the gel strength and affect the self-healing property.
  • Researchpp 4014-4021Wang, D., Li, D., Lv, D., and Liu, Y. (2014). "Reduction of the variety of phenolic compounds in bio-oil via the catalytic pyrolysis of pine sawdust," BioRes. 9(3), 4014-4021.AbstractPDF
    The objective of this study was to evaluate phenolic compounds produced from the catalytic pyrolysis of pine sawdust by commercial catalysts. Eight types of commercial catalysts consisting of SiO2, montmorillonite, α-Fe2O3, HZSM-5 (Si:Al = 25:1), ZnO, γ-Fe2O3, HZSM-5 (Si:Al = 50:1), and nano-HZSM-5 (Si:Al = 50:1) were screened in a fixed bed reactor at a reaction temperature of 500 °C and a vapor residence time of 3 s. All the tested commercial catalysts exhibited different catalytic performances for the adjustment of the composition of the bio-oil. HZSM-5 (Si:Al = 25:1) significantly increased hydrocarbon production in the bio-oil, which is helpful for improving its heating value. The different types of phenols were reduced significantly from 17 to 7 with nano-HZSM-5 (Si:Al = 50:1); however, the phenols content also decreased from 32.6% to 23.28% compared with non-catalytic pyrolysis. Meanwhile, the addition of nano-HZSM-5 (Si:Al = 50:1) to the raw material provided the highest amount of furans (up to 38.8%) among the tested commercial catalysts. The inexpensive ZnO and γ-Fe2O3 also were surprisingly effective for the reduction of the variety of phenolic compounds detected by GC/MS, reducing that number from 17 to 10.
  • Researchpp 4022-4037Ramírez-Chan, D. E., López-Naranjo, E. J., Canto-Canché, B., Burgos-Canul, Y. Y., and Cruz-Estrada, R. H. (2014). "Effect of accelerated weathering and Phanerochaete chrysosporium on the mechanical properties of a plastic composite prepared with discarded coir and recycled HDPE," BioRes. 9(3), 4022-4037.AbstractPDF
    Solid urban wastes are a primary source of local and global contamination. One approach to slow their accumulation is by using them to obtain added-value products. One common example of these waste materials is the fiber from the husks of coconuts, i.e. coir. However, it is also known that microorganisms such as fungi can attack products containing natural fibers. In this respect, this study aimed to evaluate how the mechanical properties of an extruded composite made of 60% recycled HDPE and 40% discarded coir were affected due to accelerated weathering and Phanerochaete chrysosporium attack. The effect of P. chrysosporium on the materials’ mechanical properties before and after weathering, using an accelerated weathering (AW) test device, was evaluated by means of tensile and flexural analysis following ASTM standards. Samples were also characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR spectroscopy and SEM showed that both types of treatment degraded the surfaces of the tested samples. However, the mechanical performance was not seriously affected, which means that other fungal species would affect the composites to a lesser extent.
  • Researchpp 4038-4049Gominho, J., Lopes, C., Lourenço, A., Simões, R., and Pereira, H. (2014). "Eucalyptus globulus stumpwood as a raw material for pulping," BioRes. 9(3), 4038-4049.AbstractPDF
    In this study, Eucalyptus globulus stumpwood samples collected from six different sites in Portugal were evaluated for their ease of pulping, using two delignification processes (kraft and alkaline sulfite-anthraquinone-methanol (ASAM)). Morphologically, the stumpwood included fibers with a mean length of 0.930 mm, diameter of 21.4 µm, lumen width of 9.1 µm, and cell-wall thickness of 6.1 µm. The Runkel ratio varied between 1.0 and 1.9, and the slenderness ratio ranged between 50.6 and 35.1. ASAM pulps presented higher yields and kappa numbers (49.3% and 36, respectively) when compared to kraft pulps (42.7% and 14, respectively). Extractive-free material increased pulp yield (51.7% and 47.5% for ASAM and kraft, respectively) and decreased kappa number (18 and 11). The kraft pulps showed a coarseness of 0.096 mg/m, curl of 5.2%, and 16.7% kinked fibers, while for the ASAM pulps, these values were 0.105 mg/m, 5.2%, and 16.3%, respectively.
  • Researchpp 4050-4062Zhang, Z. B., Lu, Q., Ye, X. N., Xiao, L. P., Dong, C. Q., and Liu, Y. Q. (2014). "Selective production of phenolic-rich bio-oil from catalytic fast pyrolysis of biomass: AbstractPDF
    Phenolic-rich bio-oil can be selectively produced from catalytic fast pyrolysis of biomass impregnated with K3PO4, K2HPO4, or KH2PO4. In this study, the catalytic effects of the three catalysts on the pyrolytic product distribution were investigated and compared via analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments. The results indicated that the three catalysts were all able to inhibit the pyrolytic decomposition of holocellulose to form volatile organic products, while promoting the formation of phenolic compounds from lignin. Hence, phenolic-rich bio-oil could be selectively produced. Among the three catalysts, K3PO4 and K2HPO4 possessed similar capability to increase the yield of the phenolics, which was better than KH2PO4. The phenolic contents among the total pyrolytic products steadily increased as the K3PO4 or K2HPO4 dosage increased. The maximal peak area of the phenolics reached as high as 68.8% (at 50 wt.% K3PO4) or 50.6% (at 50 wt.% K2HPO4) of the total peak area. Therefore, based on these results, K3PO4 was the best catalyst for the selective production of phenolic-rich bio-oil.
  • Researchpp 4063-4075Chen, Y., Fan, D., Qin, T., and Chu, F. (2014), "Thermal degradation and stability of accelerated-curing phenol-formaldehyde resin," BioRes. 9(3), 4063-4075.AbstractPDF
    In order to study the thermal stability of accelerated-curing PF resin, the curing behavior of fresh PF resin was investigated in the presence of single accelerator of methylolurea derivatives (MMU), magnesium hydrate (Mg(OH)2), 25% aqueous solution of sodium carbonate (Na2CO3), and propylene carbonate (PC). Also their optimum combination was added in fresh PF resin. The thermal stability of cured phenol-formaldehyde (PF) resins was studied using thermogravimetric analysis TG/DTA in air with heating rates of 5, 10, 15, and 20 °C min-1. Thermal degradation kinetics were investigated using the Kissinger and Flynn-Wall-Ozawa methods. The results show that these accelerators can promote fresh PF resin fast curing, and the degradation of accelerated-curing cured PF resin can be divided into three stages. Single accelerator MMU, Mg(OH)2, and Na2CO3 can promote fresh PF curing at low temperatures in the first stage, while the structure of PF resin which was added with MMU and PC was more rigid, according to thermal degradation kinetics. A novel fast curing agent which is compound with MMU+Na2CO3 for PF resin is proposed; not only can it maintain the advantage of fast curing of the single accelerator Na2CO3, but it also improves the thermal stability of PF resin.
  • Researchpp 4076-4093Coban, H. O., and Eker, M. (2014). "A hierarchical approach to estimate spatially available potential of primary forest residues for bioenergy," BioRes. 9(3), 4076-4093.AbstractPDF
    One of the major steps in setting up a bioenergy utilization system is to determine the potential availability of forest biomass. This study illustrates the methodology of estimating the spatial availability of primary forest residues in naturally occurring brutian pine forests, which are considerable components of forest biomass. A spatial database system was created to respectively calculate the theoretical, technical, and spatially economical biomass potentials that were subject to limitation by stand ages, forest functions, site indexes, slopes, and distance zones. To quantify primary forest residues (PFR), the conversion rates were processed, ranging from 24.1% to 26% of allowable cut volume for early thinning, 15 to 20% for thinning, and 11.1% for final felling. The results showed that the total accumulation of theoretical primary forest residues was 86,554.7 green tons in 10 years’ time, 71% of which could be ecologically available. Furthermore, the spatially available biomass potential was 6,095.4 tons per year within a radial distance of 30 km. In the future, the proposed hierarchical process can be applied to brutian pine stands in the Mediterranean region using a larger dataset that will provide a truer representation of the regional variation.
  • Researchpp 4094-4107Gao, X., Chen, K.-L., Zhang, H., Peng, L.-C., and Liu, Q.-X. (2014). "Isolation and characterization of cellulose obtained from bagasse pith by oxygen-containing agents," BioRes. 9(3), 4094-4107.AbstractPDF
    The environmentally-friendly procedure of oxygen treatment (O) and peroxide treatment with oxygen and anthraquinone as a catalyst (Po-AQ) was studied for isolation of cellulose from bagasse pith (BP) mainly consisting of parenchyma cells. The optimal conditions were: 20% alkali dosages with 12% BP consistency at 120 °C for 3 h under 0.6 MPa initial oxygen pressure for the O step; then 8% H2O2, 20% NaOH, and 0.3% AQ charges with 8% BP consistency at 120 °C for 6 h under the same oxygen pressure for the Po-AQ step. And the optimum process was: BP pretreated by cool-water extraction was firstly O-treated, and after finishing O treatment, intermediate pulp which was manually separated from effluent, was continuously processed by Po-AQ treatment. Based on the conditions above, this process can yield 37.1% of cellulose sample, containing 7.01% hemicelluloses and 0.57% lignin. The representative samples were characterized by gas chromatography (GC), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM).
  • Researchpp 4108-4116Behjou, F. K., Mollabashi, O. G., and Amirahmadi, N. (2014). "Effects of management on the amount and characteristics of woody debris in mixed stands of Caspian forests," BioRes. 9(3), 4108-4116.AbstractPDF
    Woody debris (WD), including coarse woody debris (CWD) and fine woody debris (FWD), is an essential structural and functional component of forest ecosystems. This study was carried out in Caspian hardwood forest sites. In this study, the volume and composition of WD were inventoried by line intersect sampling and fixed area plot sampling in unmanaged and managed forests on 6 compartments (3 managed and 3 unmanaged). Estimates of the total volume of WD in managed and unmanaged forests ranged from 11.9 m3.ha-1 to 25.82 m3.ha-1, respectively. The results of independent t tests indicated that the amount of CWD in the unmanaged forests was significantly higher than CWD in the managed ones (t22, 0.05 = 2.64, P = 0.015). Also, the results of independent t tests indicated that the amount of FWD in the managed forests was significantly higher than FWD in unmanaged forests (t4, 0.05 = 5.07, P = 0.007). In the unmanaged forests, WD in decay classes 3, 4, and 5 accounted for 77% of the total WD volume, but in the managed forests, WD in decay classes 1 and 2 accounted for 87% of the total WD volume. The results suggest preserving the current unmanaged forests (protected forests) and maintaining the structural and functional integrity of woody debris.
  • Researchpp 4117-4127Ren, W., Zhang, D., Wang, G., and Cheng, H. (2014). "Mechanical and thermal properties of bamboo pulp fiber reinforced polyethylene composites," BioRes. 9(3), 4117-4127.AbstractPDF
    The purpose of this study was to investigate the mechanical and thermal properties of high-density polyethylene (HDPE) composites reinforced by bamboo pulp fibers (BPF). Using a twin-screw extruder, polymer composites were fabricated using BPF and bamboo flour (BF) as the reinforcement and HDPE as the matrix. Tensile and flexural tests of the HDPE composites were performed to determine the mechanical properties under different conditions. The thermal properties of HDPE composites were characterized by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The results showed that BPF improved the mechanical and thermal properties of the polymer composites more than did BF. The tensile and flexural strength of composites with 30 wt% BPF were increased by 61.46% and 22.94%, respectively, while the tensile and flexural modulus were increased by 84.52% and 27.30%, respectively. Compared to composites with 50 wt% BF, the T5% of composites with 50 wt% BPF increased by 20.18 °C. As the BPF content increased, the storage modulus (E’) and loss modulus (E”) initially increased, followed by a decrease. Compared to the BF/HDPE composites, BPF/HDPE composites reinforced at 30 wt% had a higher storage modulus (E’) and loss modulus (E”) and lower damping parameter (tanδ).
  • Researchpp 4128-4137Wang, C. G., Chen, M. L., Jiang, Z. H., Zhang, S. Y., Wu, H., Wang, X., Pei, Y. W., and Liu, C. Q. (2014). "Biodegradable paper sheeting as agricultural covering with incorporation of bamboo pulp sludge," BioRes. 9(3), 4128-4137.AbstractPDF
    Ts, and viscose fibers by wet-laid nonwoven technology. The best process conditions included a basis weight of 30 g/m2, a bamboo paper sludge content of 10 wt%, and a polyvinyl alcohol concentration of 4 wt%. The burst strength, tearing resistance, tensile properties, resistance to water, and degradation rate were 220.65 kPa, 60.00 N, 46.10 N, 153 Pa, and 56.18%, respectively, under the best process conditions. The biodegradable paper sheeting can satisfy the demand for replacement of agricultural plastic sheeting used for such purposes as moisture retention of soil and promotion of plant growth.
  • Researchpp 4138-4149Taghiyari, H. R., Ghorbanali, M., and Tahir, P. M. D. (2014). "Effects of the improvement in thermal conductivity coefficient by nano-wollastonite on physical and mechanical properties in medium-density fiberboard (MDF)," BioRes. 9(3), 4138-4149.AbstractPDF
    The improving effect of an increase in the thermal conductivity caused by nano-wollastonite (NW) on the physical and mechanical properties of medium-density fiberboard (MDF) was studied. Nanowollastonite was applied at 2, 4, 6, and 8 g/kg, based on the dry weight of wood-chips, and compared with control specimens. The size range of wollastonite nanofibers was 30 to 110 nm. The results show that NW significantly (p < 0.05) increased thermal conductivity. The increased thermal conductivity resulted in a better curing of the resin; consequently, mechanical properties were improved significantly. Furthermore, the formation of bonds between wood fibers and wollastonite contributed to fortifying the MDF. It was concluded that a NW content of 2 g/kg did not significantly improve the overall properties and therefore cannot be recommended to industry. Because the properties of NW-6 and NW-8 were significantly similar, a NW-content of 6 g/kg can be recommended to industry to significantly (p < 0.05) improve the properties of MDF panels.
  • Researchpp 4150-4158Huang, Y., Fei, B., and Zhao, R. (2014), "Investigation of low-molecular weight phenol formaldehyde distribution in tracheid cell walls of Chinese fir wood," BioRes. 9(3), 4150-4158.AbstractPDF
    Treatment with water-soluble low-molecular weight phenol-formaldehyde resin is an effective method to improve wood properties. In this paper, plantation wood of Chinese fir was modified with low-molecular weight phenol-formaldehyde resin. The absorbance by tracheid cell walls of phenol-formaldehyde resin in treated and untreated reference samples were measured with an ultraviolet micro-spectrophotometer. The UV absorbance values of earlywood tracheids and middle lamella in treated wood were significantly increased, with an average increase of 49% and 23%, respectively. Moreover, after treatment with low-molecular weight phenol-formaldehyde resin, the UV absorbance of the earlywood tracheid cell walls of Chinese fir increased to more than 47%, regardless of whether or not the cell lumens were filled with resin. After treatment with low-molecular weight phenol-formaldehyde resin, the UV absorbance of earlywood tracheid cell walls at different locations did not vary greatly. This study provides direct support for the improvement of the physical and mechanical properties of resin-modified Chinese fir in terms of penetration of the resin into the cell walls.
  • Researchpp 4159-4172Ji, Z., Ling, Z., Zhang, X., Yang, G.-H., and Xu, F. (2014). "Impact of alkali pretreatment on the chemical component distribution and ultrastructure of poplar cell walls," BioRes. 9(3), 4159-4172.AbstractPDF
    Alkali pretreatment is one of the leading pretreatment technologies for biofuel applications. The histochemical and structural characteristics of poplar cell walls were investigated before and after sodium hydroxide pretreatment (121 oC, 2%) to understand the alterations in biomass cellular structure, which were correlated with saccharification yield. Results showed that alkali pretreatment preferentially removed lignin from the S2 of fibers, which was similar to the behaviors of coniferyl alcohol and aldehyde (lignin-CAA), exhibiting a positive correlation between removal of the two structures. Additionally, the cellulose microfibril angle was enlarged as the residence time increased during pretreatment. Scanning electron microscopy (SEM) analysis further suggested that pretreatment caused ultrastructure changes in cell walls with cracks formation on cell wall surface, especially in the areas adjacent to the cell corner middle lamellar (CCML). Accordingly, the cellulose digestibility of residues increased from 32.1% for the raw material to 53.7% for the treated samples obtained in 72 h. It can be concluded that the changes in topochemistry and ultrastructure of poplar cell walls resulting from alkali pretreatment mediated the efficiency of enzymatic hydrolysis of residues.
  • Researchpp 4173-4193Wu, G.-F., and Xu, M. (2014). "Effects of boron compounds on the mechanical and fire properties of wood-chitosan and high-density polyethylene composites," BioRes. 9(3), 4173-4193.AbstractPDF
    Wood-plastic composites (WPCs) represent a growing class of durable, low-maintenance construction materials whose use can decrease dependence on petroleum. High-density polyethylene (HDPE), chitosan (CS), wood flour (WF), boric acid (BA), and borax (BX), as well as maleic anhydride grafted polyethylene (MAPE) and polyethylene wax (PE wax), were used to develop a durable wood-plastic composite (WPC) using the extrusion method. The effects of boron compounds (3%, 6%, 9%, or 12% by weight BA/BX) on the mechanical and fire properties of the WPCs were investigated. Mechanical testing indicated that as the percentage weight of boron compounds increased, the flexural modulus, flexural strength, and tensile strength significantly decreased. Cone calorimeter tests were used to characterize the fire performance of the WPCs, and these results suggested that adding BA/BX compounds to WPCs modestly improved the fire performance. As the percentage weight of BA/BX increased from 3% to 9%, the time to ignition (TTI), heat release rate (HRR), total heat release rate (HRR-Total), smoke production rate (SPR), and specific extinction area (SEA) of the WPCs were all reduced.
  • Researchpp 4194-4204Zhang, J., Li, J., and Lin, L. (2014). "Dehydration of sugar mixture to HMF and furfural over SO42-/ZrO2-TiO2 catalyst," BioRes. 9(3), 4194-4204.AbstractPDF
  • Researchpp 4205-4211Jiang, W., Han, G., Zhou, C., Zhang, Y., and Via, B. K. (2014). "Thermal degradation kinetics of polysaccharides in fibrous materials during hot water treatment: A preliminary study," BioRes. 9(3), 4205-4211.AbstractPDF
    The current Chinese Standard (GB5889-86 1986) for wet chemistry determination assumes that there is no temperature degradation of sugars during hot water extraction. There is therefore a need to quantify this level of error and propose possible solutions for future revisions. This research was performed to investigate the thermal resistance of polysaccharides in common fibrous materials. A two-factor, two-level experimental design was employed, in which pre-oven drying and water bath temperature were controlled and changes in extractive content were measured. The thermodynamic equations for polysaccharide thermal degradation in ramie and wood were calculated. High-performance liquid chromatography (HPLC) was employed to identify monosaccharide changes during the process. This study found that polysaccharides in fibrous materials have considerable thermal degradation during oven drying at 100 °C and hot water treatment. Lower temperature combinations are recommended during hot water extractive testing when sugar analysis is to be subsequently performed.
  • Researchpp 4212-4225Chiranjeevi, P. V., Pandian, M. R., and Thadikamala, S. (2014). "Enhancement of laccase production from Pleurotus ostreatus PVCRSP-7 by altering the nutritional conditions using response surface methodology," BioRes. 9(3), 4212-4225.AbstractPDF
    Submerged culture conditions for laccase production by Pleurotus ostreatus were optimized by response surface methodology (RSM). A total of six factors, carbon (glucose), nitrogen sources (urea and peptone), 2,5-xylidine (inducer), wheat bran (lignocellulosic material), and medium pH, were optimized. A total of 50 experiments were conducted, and the obtained data were modeled using a second-order polynomial. The optimized conditions show significant improvement in laccase expression, by approximately 3.5-fold (12,124 U/L).
  • Researchpp 4226-4241Gómez, N., Quintana, E., and Villar, J. C. (2014). "Effect of paper surface properties on coated paper wettability with different fountain solutions," BioRes. 9(3), 4226-4241.AbstractPDF
    Wetting of coated papers by isopropyl alcohol (IPA)-based fountain solutions or surfactant solutions was studied in this paper. Additionally, the effect of paper surface properties on wetting was analyzed. To that end, six fountain solutions were prepared. Three solutions had increasing amounts of IPA, and three were made from surfactant-based dampening agents. Eight commercial coated papers were selected and characterized in terms of roughness and surface free energy. Paper resistance to wetting by fountain solutions was evaluated by measuring the static and dynamic contact angles. Static contact angles between the paper surface and the IPA-based fountain solutions decreased as the alcohol concentration increased, whereas the wettability with surfactant-based fountain solutions was highly dependent on their surface tensions. Paper surface free energy strongly affects the static contact angle and only moderately affects the dynamic contact angle.
  • Researchpp 4242-4252Long, T., Li, M., Chen, Y., and Zhu, X. (2014). "Study on evaporation characteristics of bio-oil and its compound models," BioRes. 9(3), 4242-4252.AbstractPDF
    In this study, bio-oil was analyzed by gas chromatography mass spectrometry (GC-MS), and the evaporation characteristics of bio-oil were studied at different heating rates (10, 20, and 30 °C/min) from 35 °C to 250 °C by a thermal analyzer (TG-DSC). The TG-DSC results of bio-oil showed that the heat requirement of bio-oil during the evaporation process ranged from 2.072´103 to 2.299´103 J/g, and the bio-oil activation energy ranged from 1.22×104 to 3.34×104 J/mol. Moreover, four models with five compounds (methanol, water, ethanol, furfural, and phenol) were established to study the bio-oil evaporation process. By comparing the TG-DSC results of bio-oil and its models at 30 °C/min, it was shown that the optimal model was model 2, which has the following chemical composition: methanol (27.10 wt.%), water (44.96 wt.%), ethanol (16.24 wt.%), furfural (4.40 wt.%), and phenol (7.30 wt.%). Model 2 exhibited a minimal relative error in dynamic parameters and characteristic curve parameters. The errors for activation energy of the TG, activation energy of the DSC, maximum endothermic rates, and the total of the heat absorption were 3.04%, 5.88%, 2.49%, and 1.06%, respectively.
  • Researchpp 4253-4265Mao, A., Shmulsky, R., Li, Q., and Wan, H. (2014). "Recycling polyurethane materials: A comparison of polyol from glycolysis with micronized polyurethane powder in particleboard applications," BioRes. 9(3), 4253-4265.AbstractPDF
    Three different types of recycled polyurethane (PUR) material, two in powder form from a pulverizing process (one < 50 µm and one < 250 µm) and one in polyol form from a glycolysis process, were used as substitutes for polymeric methylene diphenyl diisocyanate (pMDI) resin at 5%, 15%, and 30% ratio, respectively, to replace the pMDI resin for particleboard manufacturing at 8% resin loading. The reactions between pMDI resin and recycled PUR powder and polyol were investigated with Fourier transform infrared (FT-IR) spectroscopy. It was found that 5% substitution of pMDI with recycled PU powder of < 50 µm resulted in significantly higher panel internal bonding (IB) strength than pure pMDI resin, which also tended to increase panel modulus of rupture (MOR), and modulus of elasticity (MOE). Polyol did not show advantages over PUR powder in particleboard application. Increasing the size of recycled PUR powder from < 50 µm to < 250 µm decreased the panel IB, which also tended to decrease MOR and MOE. Recycling PUR materials in either powder or polyol form in particleboard manufacturing did not improve panel thickness swelling, but did appear to improve panel water absorption.
  • Researchpp 4266-4273Tůma, J., Volek, Z., Synytsya, A., Dušková, D., and Marounek, M. (2014). "Hydrophobically modified celluloses as novel cholesterol-lowering polymers," BioRes. 9(3), 4266-4273.AbstractPDF
    Hydrophobically modified celluloses were prepared by the esterification of monocarboxycellulose (MCC) and carboxymethylcellulose (CMC) with methanol, followed by the amino-de-alkoxylation of the methyl esters with n-octadecylamine. These cellulose derivatives were fed at 30 and 60 g/kg for 4 weeks to female rats. The diets were supplemented with palm fat (60 or 50 g/kg) and cholesterol (0 or 10 g/kg). There was no significant effect of amidated celluloses on the feed intake or body weight of rats. Both MCC and CMC derivatives significantly decreased the concentrations of cholesterol present in the serum and liver. The supplementation of diets with hydrophobically modified celluloses tended to increase fecal concentrations of cholesterol and coprostanol and significantly increased fecal concentrations of total neutral sterols. In rats fed diets containing cholesterol, the total serum cholesterol correlated negatively with the fecal concentrations of neutral sterols. It can be concluded that MCC-C18 and CMC-C18 are effective cholesterol-lowering agents.
  • Researchpp 4274-4287Xing, D., and Li, J. (2014). "Effects of heat treatment on thermal decomposition and combustion performance of Larix spp. wood," BioRes. 9(3), 4274-4287.AbstractPDF
    Larix spp., a wood species of low dimensional stability, was heat-treated in nitrogen at 180 to 210 °C for 6 h. Changes in the thermal decomposition and combustion behaviors of the wood after heat treatment were investigated by TGA, SEM, FTIR, and cone calorimetry. TGA confirmed the loss of hemicellulose from heat-treated Larix spp. Small cracks in the cell wall and loss of resin from the vessels of heat-treated wood were observed by SEM. Hemicellulose degradation within the heat-treated samples was indicated by decreased intensities of typical O-H and C=O stretching vibration peaks in the FTIR spectra. The HRR and MLR curves of treated wood were much lower than those of the untreated ones, which is preferable for fire safety. However, the time to ignition of treated samples decreased from 22 to 13 s and the total smoke production increased by 4.76 and 43.3% for 180- and 210 °C-treated samples, respectively, a detrimental effect on fire safety. To determine the influence of heat treatment on the combustion behaviorof Larix spp., the fire safety properties of heat-treated wood (such as wood structure building, furniture, and floors) must be studied further.
  • Researchpp 4288-4296Gaff, M., and Gáborik, J. (2014). "Effect of cyclic loading on the elasticity of beech solid and laminated wood," BioRes. 9(3), 4288-4296.AbstractPDF
    This article deals with the determination of the cyclic loading effect on the elastic modulus (Em) of beech solid and laminated wood at various thicknesses while bent in the radial direction. To identify the modulus of elasticity, a three-point static bending test was carried out. The monitored characteristics were compared for the bodies under cyclic stress vs. bodies not subject to cyclic stress. Results showed no significant effect of cyclic loading on the laminated wood elastic modulus values. Conversely, cyclic loading significantly (95% confidence interval) affects the modulus of elasticity values for solid wood. A significant impact of thickness has been observed for both types of material. The results demonstrate that the elastic modulus values decrease with increasing thickness after cyclic loading.
  • Researchpp 4297-4310Shangguan, W., Ren, H., Lv, J., Fei, B., Chen, Z., Zhao, R., and Zhao, Y. (2014). "Cell wall property changes of white rot larch during decay process," BioRes. 9(3), 4297-4310.AbstractPDF
    decreased following the first three-week infestation. Nano-indentation measurements revealed that the average MOE of infested larch flakes decreased from 24.0 to 17.1 GPa and the average hardness declined from 528.47 to 427.87 MPa following 12 weeks of infestation. After the first three weeks, the relative crystallinity, surface area, and micropore area of the infested samples increased. These parameters decreased after three weeks had elapsed. Changes in the absorption peaks observed in FTIR explained that the first three-week infestation had a strong effect on the mass loss and strength changes. This suggests that white rot fungus intensely attacked the lignin component of the biomass during the first three weeks of infestation.
  • Researchpp 4311-4322Yang, H., Zhang, X., and Hong, Y. (2014). "Classification, production, and carbon stock of harvested wood products in China from 1961 to 2012," BioRes. 9(3), 4311-4322.AbstractPDF
    China boasts a large production, import, and export volume of harvested wood products (HWP). The production, trade volume, and carbon stock of HWP can be used as valuable reference data for the economic growth and the participation of China in climatic negotiation. This research counts the production of major Chinese HWP between 1961 and 2012 according to the HWP classification standards of the Food and Agricultural Organization. The total forestry production value of China reached RMB 3,950 billion in 2012. The total forestry production value and the HWP production of China have been rising steadily. By applying the carbon accounting model of HWP under the stock change approach, this research estimates and analyzes the carbon stock of Chinese HWP from 1961 to 2012. The development of Chinese HWP inventories within this period can be roughly divided into three phases, which show a general uptrend. In 2012, the total carbon stock of Chinese HWP reached 888.01 million tons, whereas the annual increment of Chinese HWP reached 50.78 million tons. Therefore, HWP significantly contributes to the positive growth of Chinese carbon stock.
  • Researchpp 4323-4335Fu, S., Hu, J., and Liu, H. (2014). "Inhibitory effects of biomass degradation products on ethanol fermentation and a strategy to overcome them," BioRes. 9(3), 4323-4335.AbstractPDF
    The influence of buffers, as well as inhibitors such as formic acid, furfural, HMF, guaiacol, and vanillin, on ethanol formation was investigated. Compared to phosphoric buffer, the acetic and citric buffers were less inhibitory on ethanol fermentation. The addition of formic acid (2.5 g/L) to the buffer reduced the ethanol yield by 8%. Guaiacol (3 g/L) and vanillin (2.5 g/L) decreased ethanol production by 50% and 20%, respectively. Furfural and HMF delayed the yeast fermentation without reducing the total yield. The fermentation was seriously inhibited by the mixture of furfural (1 g/L), HMF (1 g/L), formic acid (1 g/L), vanillin (1 g/L), and guaiacol (1 g/L). The ethanol yield of the fermentation based on enzymatic hydrolyzate from treated biomass was 82%. The addition of 1 g/L MgSO4 as a shielding protector rehabilitated nearly 100% of the total yield.
  • Researchpp 4336-4342Hao, J., Deng, C., Wang, X., and Hu, J. (2014). "Study of dispersion characteristics of mercerized pulp," BioRes. 9(3), 4336-4342.AbstractPDF
    Mercerized pulp is widely used in the filter paper industry. But the major challenge facing users of the pulp is its difficult dispersion in water. It was found that by applying a suitable degree of beating it was possible to achieve better dispersion than the original pulp. The beating degree before and after beating was almost the same. But the properties of filter paper were greatly improved after beating, especially for the formation index and burst index. The morphology of beaten fibers was analyzed by SEM with both the freeze-drying and air drying sample preparation process. The results showed that the primary cell wall of the beaten mercerized pulp fibers were swollen and partly peeled from the fiber main body after beating, as revealed by micrographs obtained after freeze-drying. The results suggest that the improvement of the fiber dispersion in water was caused by these changes on the fiber surface.
  • Researchpp 4343-4357Nasser, R. A. (2014). "An evaluation of the use of midribs from common date palm cultivars grown in Saudi Arabia for energy production," BioRes. 9(3), 4343-4357.AbstractPDF
    This study was conducted to evaluate the suitability of date palm midribs as an alternative source for energy production. The physical properties, chemical constituents, and fuel characteristics of the midribs of five common date palm cultivars (Barhi, Khalas, Khodry, Sukkari, and Sullaj) were determined. In addition to the frond base, the midribs were divided into three distinct parts (base, middle, and top) along the frond. The results showed that both the fibre saturation point and volumetric shrinkage of the date palm midribs were much higher than those of solid wood. There were significant differences in all of the chemical constituents of the midribs between the five date palm cultivars. The date palm midribs were characterised by higher levels of extractives (19.3% for Barhi to 21.7% for Sullaj) and ash contents (3.3% for Khodry to 5.8% for Khalas). The other chemical constituents were within the ranges found for other lignocellulosic materials, including softwood and hardwood. The heating values for the midribs ranged between 17.30 MJ/kg for the Barhi cultivar and 17.89 MJ/kg for the Khodry cultivar. The higher ash content and lower density of date palm midribs makes them less desirable for energy production. It can therefore be concluded that the frond base is not suitable for energy production.
  • Researchpp 4358-4368Lee, Y. M., Lee, H., Kim, J. S., Lee, J., Ahn, B. J., Kim, G.-H., and Kim, J.-J. (2014). "Optimization of medium components for β-glucosidase production in Schizophyllum commune KUC9397 and enzymatic hydrolysis of lignocellulosic biomass," BioRes. 9(3), 4358-4368.AbstractPDF
    Medium components for β-glucosidase (BGL) production in Schizophyllum commune KUC9397 were optimized using a central composite design and response surface methodology. From the various medium components tested, cellulose, soy peptone, and thiamine HCl were selected as the optimal carbon, nitrogen, and vitamin sources, respectively. The highest BGL production was obtained with 2.96% cellulose, 2.30% soy peptone, and 0.11% thiamine HCl. BGL production in the optimized medium was increased 7.2-fold compared to production in an unoptimized medium. Crude enzyme preparation from S. commune KUC9397 was used to saccharify pretreated lignocellulosic biomass. The crude enzyme preparations showed statistically equal saccharification rates as Cellobiase, a commercial BGL. This finding indicates that crude enzymes produced by S. commune KUC9397 have good potential for application in cellulosic biomass conversion systems in place of Cellobiase.
  • Researchpp 4369-4381Feng, Q., Li, J., Cheng, H., Chen, F., and Xie, Y. (2014). "Synthesis and characterization of porous hydrogel based on lignin and polyacrylamide," BioRes. 9(3), 4369-4381.AbstractPDF
    A porous lignin-containing hydrogel was developed for dye removal via graft copolymerization of acetic acid lignin (AAL) and acrylamide (AAm), in the presence of ethyleneglycol dimethacrylate (EGDMA) as a crosslinker and H2O2 as an initiator. AAL was characterized by FT-IR and TGA. After being washed to remove impurities, the hydrogel was characterized by FT-IR, TGA, SEM, and swelling ratio. FT-IR spectra suggested that AAL was present in the hydrogel. The TGA curves revealed that the introduction of AAL had no significant impact on the thermal stability of PAAm. SEM images showed that the honeycomb-like structure of the hydrogel was improved with increasing AAL content. The swelling ratio data showed that the hydrogel with a high AAL/AAm ratio was sensitive to pH. Furthermore, increased lignin content of the hydrogel favors the dye adsorption.
  • Researchpp 4382-4391Wu, W., Wang, Z., Jin, Y., Matsumoto, Y., and Zhai, H. (2014). "Isolation of cellulolytic enzyme lignin from rice straw enhanced by LiCl/DMSO dissolution and regeneration," BioRes. 9(3), 4382-4391.AbstractPDF
    Ball-milled rice straw was dissolved in a lithium chloride/dimethyl sulfoxide (LiCl/DMSO) solvent system, regenerated, and subjected to enzymatic hydrolysis to obtain regenerated cellulolytic enzyme lignin (RCEL). The structure of the isolated lignin was characterized by elemental analysis, gel permeation chromatography (GPC), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and proton nuclear magnetic resonance (1H NMR). Alkaline nitrobenzene oxidation (NBO) was conducted to analyze the structural characteristics of the in-situ lignin. The results showed that the rice straw RCEL was composed of p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) phenylpropane units, with relatively high amounts of H units. The yield of RCEL is about 5% units higher than that of cellulolytic enzyme straw lignin (CEL) on the basis of total lignin in the original rice straw. When compared to the CEL obtained by the traditional method, there were no observed differences versus RCEL in terms of the elemental compositions, NBO product yields, and S/G ratio. The weight-average molecular weight of RCEL was 6835, which was lower than that of CEL, indicating that some rice straw lignin linkages were cleaved during LiCl/DMSO dissolution.
  • Researchpp 4392-4409Kaboorani, A., and Blanchet, P. (2014). "Determining the linear viscoelastic region of sugar maple wood by dynamic mechanical analysis," BioRes. 9(3), 4392-4409.AbstractPDF
    Dynamic mechanical analysis (DMA) is a powerful analytical technique to study wood structure and properties. In order to draw firm conclusions from results obtained by DMA, strain rate of tests conducted by DMA should be within the linear viscoelastic region (LVR) of the tested material. In this study, the LVR limit of sugar maple (Acer saccharum Marsh.) wood specimens was determined in the three directions under a range of temperature and relative humidity (RH) conditions. The results demonstrated that wood had very different LVR limits in the different directions. The longitudinal direction had much lower LVR limits than the radial and tangential directions. While LVR limits were not strongly affected by changes in temperature and RH in the longitudinal direction, they proved very sensitive to these factors in the tangential direction. The results of this study showed the importance of determining LVR limits before running any test by DMA.
  • Researchpp 4410-4420Suchomel, J., Belanová, K., Gejdoš, M., Němec, M., Danihelová, A., and Mašková, Z. (2014). "Analysis of fungi in wood chip storage piles," BioRes. 9(3), 4410-4420.AbstractPDF
    There are health and safety risks involved in the production and storage of forest biomass. Fungi that are formed in the stored piles of wood chips pose a high potential risk for human health. Three experimental piles, containing wood chips from three species of trees, were created. They included European beech (Fagus sylvatica), common aspen (Populus tremula), and European spruce (Picea abies). The piles created were in the shape of a pyramid with the base measuring 4 m x 4 m. In each pyramid, 3 points of measurements were established at 0.5 m, 1.0 m, and 1.5 m above the ground. Temperature, relative moisture, and the number of microscopic fungi colonies were monitored at each point of measurement in the period between 13th December 2011 and 6th June 2012. The highest relative moisture content was recorded in the pile with the European spruce. The aim of the experiment was to identify the genus and species of fungi that are formed in the chip piles during long-term storage and which pose a potential risk for human health. In total, 5 species and 8 genera of fungi were identified in the collected samples, whereby there was significant growth only during the first 4 to 6 months of storage.
  • Researchpp 4421-4429Yu, T., Xu, G., Wang, X., Yang, J., and Hu, J. (2014). "Fabrication of oil-water separation filter paper by simple impregnation with fluorinated poly-acrylate emulsion," BioRes. 9(3), 4421-4429.AbstractPDF
    A fluorinated poly-acrylate emulsion with various fluorine contents was prepared by a seeded semi-continuous emulsion polymerization method and applied to filter paper for oil-water separation applications. The effects of surface wetting behavior on the oil-water separation efficiency of the prepared filter paper were studied. The results show that the prepared highly hydrophobic and superoleophilic filter paper presented 94.45 wt% water separation efficiency and strong mechanical strength. In addition, the oil-water separation stability and durability of the filter paper were also tested and shown to be suitable for use in real oil-water separation applications. These properties indicate that the filter paper has great potential applications in the oil-water separation industry.
  • Researchpp 4430-4440Shibata, S., Senaha, I., and Abral, H. (2014). "Effect of time-dependent moisture absorption on surface roughness of bagasse and oil palm fibers/polypropylene composites," BioRes. 9(3), 4430-4440.AbstractPDF
    The effect of time-dependent moisture absorption on the surface roughness in natural fiber/polypropylene composites after a hot-press molding was studied. The results showed that the moisture absorption in both bagasse and oil palm natural fiber composites correlated closely with time-dependent surface roughness in the composites. The surface roughness in all natural fiber composites increased with an increase of moisture absorption up to 50 d. The fibers absorbed moisture and swelled due to hydroxyl groups of celluloses in the natural fibers, which caused an increase in surface roughness. Time-dependent tests found that the surface roughness in long fiber composites was larger than that in short fiber composites due to inhomogeneous dispersion of long fibers in the vicinity of the surface of composites. The increase in surface roughness of oil palm composites was 55% that of the bagasse composites due to the lower temperature of thermal decomposition in oil palm fibers than in bagasse fibers. Thermal decomposition decreased the number of hydroxyl groups in fibers during heating and resulted in a decrease in moisture absorption in the palm fibers. Furthermore, the effect of the carbodiimide treatment on bagasse fibers was confirmed to reduce moisture absorption for both the fibers and the composites.
  • Researchpp 4441-4448Cheng, H., Wu, S., and Liu, C. (2014). "Study on the mechanism of the pyrolysis of a lignin monomeric model compound by in situ FTIR," BioRes. 9(3), 4441-4448.AbstractPDF
    The in situ Fourier transform infrared (FTIR) spectroscopy technique was used as an online method for fundamental mechanistic studies of the pyrolysis of a lignin monomeric model compound. The formation of important reaction intermediates was revealed. Three major decomposition routes were shown: P1, dehydration at approximately 270 °C; P2.1, demethylation at approximately 350 °C; and P2.2, H-abstraction at approximately 430 °C. A free reaction of the pyrolysis of the lignin model compound was suggested based on the results. The comparative results showed that the methyl group was the initiator of many secondary reactions.
  • Researchpp 4449-4467Tisserat, B., Reifschneider, L., Carlos López Núñez, J., Hughes, S. R., Selling, G., and Finkenstadt, V. L. (2014). "Evaluation of the mechanical and thermal properties of coffee tree wood flour - polypropylene composites," BioRes. 9(3), 4449-4467.AbstractPDF
    Columbian coffee trees are subject to frequent replacement plantings due to disease and local climate changes, which makes them an ideal source of wood fibers for wood plastic composites (WPC). Composites of polypropylene (PP) consisting of 25% and 40% by weight of coffee wood flour (CF) and 0% or 5% by weight of maleated PP (MAPP) were produced by twin screw compounding and injection molding. Composites containing MAPP had significantly improved tensile and flexural properties compared to neat PP or composites without MAPP. Excellent mechanical properties were obtained with CF relative to conventional wood fillers. Izod impact resistances of CF composites were significantly lower than neat PP although WPC containing MAPP were superior to WPC without MAPP. Bio-based fiber composites made by mixing CF in equal portions with other fiber sources were evaluated to determine the compatibility of using CF with other sources of filler materials. Soaking of tensile bars of the various CF blends in distilled water for 35 days may alter their mechanical properties and result in weight gain. Differential scanning calorimetry and thermogravimetric analysis were conducted on the neat PP and bio-composites to evaluate their thermal properties as they relate to potential degradation during conventional thermoplastic resin processing.
  • Researchpp 4468-4476Gaff, M., and Gáborík, J. (2014). "Evaluation of wood surface quality after 3D molding of wood by pressing," BioRes. 9(3), 4468-4476.AbstractPDF
    The goal of this study was to develop and test an appropriate method for the evaluation of surface quality and to identify and quantify the quality of a surface modified by 3D molding. New software was developed to evaluate the surface quality based on the identification of macroscopic defects such as cracks within a scanned area. The influence of specific factors that affect the development of cracks during the uneven pressing process was assessed. Based on the measured and evaluated results, a process combination of factors was designed which yielded an embossed surface that was formed with the lowest proportion of cracks and with sufficient shape stability. In this work, 432 groups of test pieces were monitored, with each piece exposed to different combination of factors. Based on the measured and evaluated results, we found a combination that provided the lowest crack ratio. This innovative method will contribute to the knowledge of embossed surface quality and to the improvement of the uneven pressing process for wood surfaces.
  • Researchpp 4477-4488Su, L., and Fang, G. (2014). "Characterization of cross-linked alkaline lignin/poly (vinyl alcohol) film with a formaldehyde cross-linker," BioRes. 9(3), 4477-4488.AbstractPDF
    , industrial alkaline lignin/poly (vinyl alcohol) (PVOH) cross-linked films, industrial alkaline lignin/poly (vinyl alcohol) blend films, and neat poly (vinyl alcohol) films were prepared by casting. The films were investigated by Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry analysis (TGA), and dynamic mechanical analysis (DMA). The water contact angles for the three kinds of films were studied as well. The crosslinking reaction between alkaline lignin and PVOH was strong, which was attributed to the high hydrolysis degree of PVOH and the high reactivity of formaldehyde. Compared with the neat PVOH film, the crystallinity of the cross-linked film decreased slightly; the thermal stability of the cross-linked film was higher; DMA analysis showed that the Tg and the tanδ magnitude of the alkaline lignin/PVOH reaction film both decreased slightly. Lignin and the cross-linking reaction both improved the water resistance of films. Therefore, this research has provided a detailed analysis of the characterization of the films while exploring the potential of direct usage of industrial alkaline lignin in polymer materials.
  • Researchpp 4489-4502Chu, Q., Huang, Y., Li, X., Fan, Y., Jin, Y., Yu, S., and Yong, Q. (2014). "Improved enzymatic hydrolysis of corn stover by green liquor pretreatment and a specialized enzyme cocktail," BioRes. 9(3), 4489-4502.AbstractPDF
    An effective strategy for sugar production from corn stover was established through a combination of green liquor pretreatment (8% total titratable alkali charge, 40% sulfidity, 140 °C, and 1 h) and enzymatic hydrolysis with a specialized enzyme cocktail. Green liquor pretreatment was demonstrated as an effective first step for sugar production due to the selective removal of lignin (39.70%), high carbohydrate recovery yield (81.53%), and obvious enhancement of enzymatic hydrolysis after pretreatment. When a specialized enzyme cocktail (cellulase, β-glucosidase, and xylanase at a ratio of 1:1.88:6.61, supplemented with 0.05 g of PEG 6000 per g of glucan) was applied, near-theoretical hydrolysis yield was achieved (glucan hydrolysis yield of 93.53% and xylan hydrolysis yield of 86.00%). A total fermentable sugar production of 50.14 g was obtained per 100 g of dry corn stover, including 36.08 g of glucose and 14.06 g of xylose.
  • Researchpp 4503-4509Chen, Z., Li, C., Song, Z., and Qian, X. (2014). "Wet strength and antibacterial performance of cellulosic paper induced by maleic anhydride-acylate chitosan," BioRes. 9(3), 4503-4509.AbstractPDF
    Paper sheets were dipped in maleic anhydride-acylated chitosan (MAAC) to enhance their wet strength and antibacterial performance. The wet strength of paper sheets treated with MAAC or chitosan solutions and cured at 90 and 170 °C was investigated. Escherichia coli was used to evaluate the antibacterial performance of the treated paper sheets. The antibacterial performance was determined by measuring the absorbance at 610 nm based on the turbidity of the bacterial suspension on the surface of the treated paper sheets. The MAAC performed better than chitosan in improving wet strength, especially in the case of permanent wet strength. Paper sheets treated with MAAC under certain conditions resulted in 23 to 33% improvements in the permanent wet strength. As a result of the surface treatment, a reduction of at least 80% in E. coli growth was observed. The MAAC was more efficient in inhibiting the growth of E. coli than chitosan.
  • Researchpp 4510-4516Liu, M., Zhang, Q., and Zhan, H. (2014). "Headspace gas chromatographic method for the determination of hydrogen peroxide residues in bleaching effluent," BioRes. 9(3), 4510-4516.AbstractPDF
    A simple, rapid, accurate, and practical headspace gas chromatographic method is proposed for the determination of hydrogen peroxide residues in bleaching effluent. of hydrogen peroxide with ceric sulfate, under acidic conditions, where hydrogen peroxide is converted to oxygen, which is then measured using headspace gas chromatography (HS-GC) coupled with a thermal conductivity detector (TCD). The results show that a complete conversion of hydrogen peroxide to oxygen can be achieved within 3 min at a temperature of 70 °C and a H2SO4 concentration of 0.2 M. Under optimized conditions, the method has an excellent measurement precision (relative standard deviation = 0.78%) and good recovery (100.2 ± 2.6%). does not require the use of organic reagents.
  • Researchpp 4517-4527Sajab, M. S., Chia, C. H., Zakaria, S., and Sillanpää, M. (2014). "Removal of organic pollutants and decolorization of bleaching effluents from pulp and paper mill by adsorption using chemically treated oil palm empty fruit bunch fibers," BioRes. 9(3), 4517-4527.AbstractPDF
    Treatment of bleaching effluents from pulp and paper mills using oil palm empty fruit bunch (EFB) fibers as an adsorbent was conducted to remove color and organic pollutants. Empty fruit bunch fibers were chemically modified with polyethylenimine to enhance the adsorption capacity toward anionic species in the effluents. Effluents from the primary clarifier and aerated treatment pond were treated, and the performance of the adsorbent was investigated in terms of decolorization, total organic carbon, and oxygen demand level. Increasing adsorbent dosage and lower pH resulted in greater adsorption performance. The highest decolorization and reduction of total organic carbon of the effluents were 95.0% and 58.2%, respectively. The adsorption equilibrium can be achieved after 4 h of the adsorption process.
  • Researchpp 4528-4539Cao, S., Ma, X., Lin, L., Huang, F., Huang, L., and Chen, L. (2014). "Morphological and chemical characterization of green bamboo (Dendrocalamopsis oldhami (Munro) Keng f.) for dissolving pulp production," BioRes. 9(3) 4528-4539.AbstractPDF
    With the sustained growth of dissolving pulp demand all over the world, the search for alternative bamboo materials has come into focus in China due to the shortage of wood and the abundance of bamboo resources. In this study, to obtain updated information concerning green bamboo growing in southeastern China and to develop its processing technologies for dissolving pulp, the fiber morphology, chemical composition, elemental composition, degree of polymerization (DP) of cellulose, and crystallinity index (CrI) of cellulose were investigated. The experimental results show that green bamboo has potential for use as dissolving pulp because it has a lower Runkel ratio and fines content than moso bamboo, and a much lower lignin content and similar α-cellulose and hemicellulose contents compared to softwoods and hardwoods. Compared to the cortex and culm, the node had the shortest fibers and more than 30% of fines, the highest content of extractives and lignin, and the lowest α-cellulose content. As a result, a de-knotting operation prior to cooking can contribute to the production of high-grade dissolving pulp. The DP and CrI of cellulose from the node were much lower than that of cellulose from the culm and cortex. Moreover, green bamboo had the high content of ash, primarily distributed in the cortex. The concentration of Si was 4487 ppm in the cortex, nearly five times higher than that in the culm and node.
  • Researchpp 4540-4551Yan, Y., Dong, Y., Chen, H., Zhang, S., and Li, J. (2014). "Effect of catalysts and sodium hydroxide on glyoxal-treated wood," BioRes. 9(3), 4540-4551.AbstractPDF
    Treatment of poplar wood using glyoxal as a non-formaldehyde cross-linking reagent was investigated. Cross-linking occurred with glyoxal in the presence of the catalysts aluminum sulfate, magnesium chloride, zinc nitrate, maleic anhydride, ammonium dihydrogen phosphate, ammonium persulfate. Ammonium persulfate was found to be the most effective single catalyst, which may be due to the synergistic catalytic effect of NH4+ and S2O82-, Further, catalyst combinations produced higher overall performance in comparison with the single one, and the optimal combination was maleic anhydride and ammonium persulfate. An increase in ammonium persulfate improved wood dimensional stability and anti-leaching properties, but weakened the hydrophobicity and deepened the colour of the modified wood. Considering the balance between anti-swelling efficiency, leachability, and water uptake, the optimum catalyst concentration was 2%. Although the addition of sodium hydroxide into a glyoxal solution can reduce wood discoloration, it may also reduce the modification efficiency.
  • Researchpp 4552-4567Pelit, H., Sönmez, A., and Budakçı, M. (2014). "Effects of ThermoWood® process combined with thermo-mechanical densification on some physical properties of Scots pine (Pinus sylvestris L.)," BioRes. 9(3), 4552-4567.AbstractPDF
    Effects of heat treatment on some physical properties of Scots pine (Pinus sylvestris L.) wood densified using a thermo-mechanical method were determined. Samples were densified in the radial direction with a specially designed hydraulic press machine with target compression ratios of 20% and 40%, and at 110 °C and 150 °C. Then, heat treatment was applied to the samples during 2 h at three different temperatures (190 °C, 200 °C, and 210 °C). In order to determine the changes occurring in physical properties, tests of actual compression ratio, spring-back, compression ratio recovery effect, swelling (TS 4084) in compression direction (radial), and density (TS 2472) were conducted. According to results of the research, at the same target compression ratio (20% or 40%), higher actual compression ratio and density increase were observed in the samples densified at 110 ºC in comparison to those densified at 150 ºC. While an increase of 42% in density was being obtained, small rates of decreases up to 4% were observed after heat treatment. Application of heat treatment and increase of treatment temperature significantly influenced dimensional stability of densified Scots pine. Furthermore in comparison to samples without heat treatment, effects of compression ratio recovery were reduced by 80%.
  • Researchpp 4568-4580Zhang, S., Li, W., Zeng, X., Sun, Y., and Lin, L. (2014). "Production of 2,5-diformylfuran from biomass-derived glucose via one-pot two-step process," BioRes. 9(3), 4568-4580.AbstractPDF
    As a furan derivative from 5-hydroxymethylfurfural (HMF) or other biomass-based carbohydrates, 2,5-diformylfuran (DFF) is one of the most important platform molecules in the organic chemicals industry. Although it has many potential applications in the future, the production of DFF on a large scale is currently a challenge. As an alternative to the production of DFF from HMF, the target product DFF could be obtained from biomass-derived glucose with a complex catalytic system (AlCl3·6H2O/NaBr and a vanadium compound assisted with molecular oxygen) carried out in N,N-dimethylformamide (DMF). In this research, reactions were conducted in reactors with different capacities. The results showed that DFF yields based on glucose could reach 35 to 48% with almost complete transformation of glucose. This one-pot two-step reaction is characterized by the abundance and low cost of the starting materials and by the elimination of the separation and purification of HMF. This has great potential for applications in the future production of DFF on a large scale after further advancements and optimizations.
  • Researchpp 4581-4595Yu, H., Li, X., Xing, Y., Liu, Z., and Jiang, J. (2014). "A sequential combination of laccase pretreatment and enzymatic hydrolysis for glucose production from furfural residues," BioRes. 9(3), 4581-4595.AbstractPDF
    Furfural residues (FRs) were pretreated with laccase or a laccase-mediator (1-hydroxybenzotriazole, HBT) system to produce fermentable sugar for bioethanol production. Compared to laccase-only pretreatment, laccase-mediator pretreatment dissolved more lignin. Approximately 10.5% of the initially present lignin was removed when FRs were treated with a laccase loading of 100 U/g of dry substrate in 1% (w/w) HBT at 48 °C for 24 h in an acetate buffer (pH 4.8). The enzymatic saccharification process was carried out by a combined laccase or laccase-mediator pretreatment without washing of the treated solids. The results showed that active laccase had a negative effect on the rate and yield of enzymatic hydrolysis. Laccase-oxidized HBT seriously reduced glucose yield. However, non-oxidized HBT increased glucose yield when laccase was deactivated at 121 °C for 20 min prior to enzymatic hydrolysis. The highest glucose yield, 80.9%, was obtained from the substrate pretreated with 100 U/g of dry substrate laccase and 1% (w/w) HBT at 48 °C for 24 h in an acetate buffer (pH 4.8). Furthermore, the structures of FRs before and after laccase-mediator pretreatment were characterized by scanning electron microscopy (SEM) and Fourier Transform Infrared spectroscopy (FT-IR).
  • Researchpp 4596-4607Wang, C., Lyu, G., Yang, G., Chen, J., and Jiang, W. (2014). "Characterization and hydrothermal conversion of lignin produced from corncob acid hydrolysis residue," BioRes. 9(3), 4596-4607.AbstractPDF
    Lignin is one of the main components of corncob acid hydrolysis residue (CAHR). It can be used as a feedstock for biomaterial and biochemical production via biorefining. In this study, CAHR lignin was extracted, and enzymatic/mild acidolysis lignin (EMAL) was produced to ensure efficient lignin recovery. Next, hydrothermal conversion of the EMAL was carried out. The influences of process conditions including the temperature, time, and mass ratio of deionized water to EMAL on the hydrothermal conversion were thoroughly investigated to quantify analysis of the aromatics. EMAL produced from CAHR had a structure of the G-S-H type, in which the p-hydroxyphenyl unit was the primary structural unit, followed by the guaiacyl structural unit. The syringyl structural unit was less common. The yields (wt. %) of phenol, guaiacol, and 4-ethyl-phenol reached maxima of 1.26%, 0.75%, and 1.16%, respectively, at a reaction temperature of 310 °C and time of 30 min with a mass ratio of 80:1.
  • Researchpp 4608-4621AL-Oqla, F. M., Salit, M. S., Ishak, M. R., and Aziz, N. A. (2014). "Combined multi-criteria evaluation stage technique as an agro waste evaluation indicator for polymeric composites: Date palm fibers as a case study," BioRes. 9(3), 4608-4621.AbstractPDF
    The final features of natural fiber composites (NFCs) depend on the integrated characteristics of their constituents. In the industry today, natural agro waste fibers are evaluated using a limited number of criteria. In this work, a combined multi-criteria evaluation stage technique (CMCEST) is introduced as a simple efficient systematic indicator to enhance evaluation of the available natural agro wastes for polymeric composites. In this proposed technique, criteria affecting the proper selection of natural agro waste fibers were combined and divided into sequence stages as follows: single-evaluation-criterion (SEC), combined-double-evaluation-criterion (CDEC), combined-triple-evaluation-criterion (CTEC), etc. These stages are based on combined physical, mechanical, and economic evaluation criteria and can be extended to several further stages to include other beneficial characteristics. The effectiveness of this technique was demonstrated by evaluating coir, date palm, jute, hemp, kenaf,and oil palm fibers simultaneously. This combined evaluation criteria can lead to more informative decisions regarding selection of the most suitable fiber type for polymeric composites. The CMCEST enhancements can reveal new potential fiber types through better evaluation schemes, help achieve clearer indications of the capabilities of available agro wastes to enhance composites, and determine proper ecological waste management practices. Utilizing the proposed technique, the date palm fiber type was found to be quite promising due to beneficial characteristics revealed in CTEC, which provides a reasonable, cheap, and eco-friendly alternative material suitable for different applications.
  • Researchpp 4622-4635Li, Z., Li, W.-Z., Hu, H., Zu, S., Wang, Z., Jameel, H., and Chang, H.-M. (2014). "Pretreatment of corn stover for sugar production by a two-step process using dilute hydrochloric acid followed by aqueous ammonia," BioRes. 9(3), 4622-4635.AbstractPDF
    A novel two-step process for pretreatment of corn stover was investigated with the goal of increasing sugar recovery and decreasing the capital cost. In the process, corn stover was first treated with dilute hydrochloric acid to maximize xylan recovery, and then the residue was treated with aqueous ammonia to alter the lignin structure and swell the cellulose surface. The optimal conditions were 110 °C and 40 min for 1% dilute hydrochloric acid pretreatment with a liquid to solid ratio of 10:1 followed by aqueous ammonia pretreatment at 37% NH3, 130 °C, 30 min, and liquid to solid ratio of 6:1. Under these pretreatment conditions, the glucan and xylan recoveries were 83.2% and 97.3%, respectively, with cellulase dosage at 15 FPU/g of substrate. When the cellulase dosage was decreased from 15 FPU/g to 10 FPU/g of substrate, the glucan recovery only dropped to 70%, while the xylan recovery remained high at 95.1%. The results show that this two-step pretreatment was effective for achieving high sugar recovery from corn stover by enzymatic hydrolysis.
  • Researchpp 4636-4642He, L., Liu, Q., Song, Y., and Deng, Y. (2014). "Effects of metal chlorides on the solubility of lignin in the black liquor of prehydrolysis kraft pulping," BioRes. 9(3), 4636-4642.AbstractPDF
    The effects of CaCl2, MgCl2, FeCl3, NaCl, and AlCl3 on the solubility of lignin in the prehydrolysis kraft black liquor of Masson pine were studied using a focused-beam reflectance measurement (FBRM) instrument and UV spectra. The results showed that NaCl and AlCl3 have no obvious effects on the coagulation or solubility of lignin in the prehydrolysis kraft black liquor at high effective alkalinity. However, CaCl2, MgCl2, and FeCl3 have significant effects on the solubility of lignin in the black liquor. According to the reduction rate of UV absorbance, the effects of these chloride salts on the black liquor lignin solubility at high alkali content were as follows: AlCl3≈NaCl<MgCl2<CaCl2<FeCl3.
  • Researchpp 4643-4655Čop, M., Laborie, M.-P., Pizzi, A., and Sernek, M. (2014). "Curing characterisation of spruce tannin-based foams using the advanced isoconversional method," BioRes. 9(3), 4643-4655.AbstractPDF
    The curing kinetics of foam prepared from the tannin of spruce tree bark was investigated using differential scanning calorimetry (DSC) and the advanced isoconversional method. An analysis of the formulations with differing amounts of components (furfuryl alcohol, glycerol, tannin, and a catalyst) showed that curing was delayed with increasing proportions of glycerol or tannins. An optimum amount of the catalyst constituent was also found during the study. The curing of the foam system was accelerated with increasing temperatures. Finally, the advanced isoconversional method, based on the model-free kinetic algorithm developed by Vyazovkin, appeared to be an appropriate model for the characterisation of the curing kinetics of tannin-based foams.
  • Researchpp 4656-4666Zhang, S., Li, W., Zeng, X., Sun, Y., and Lin, L. (2014). "Aerobic selective oxidation of biomass-derived 5-hydroxymethylfurfural to 2,5-diformylfuran with active manganese dioxide catalyst," BioRes. 9(3), 4656-4666.AbstractPDF
    5-hydroxymethylfurfural (HMF) is an important bio-based platform chemical, and its aerobic selective oxidation to 2,5-diformylfuran (DFF) still remains a challenge. This work dealt with active manganese dioxide (AMD) and efficiently catalyzed HMF oxidation to DFF with a yield of ~73% at 393 K and 60 bar O2 in N,N-Dimethylformamide (DMF). Through analysis of liquid products and the catalyst characterization using X-ray diffraction (XRD), a scanning electron microscope (SEM), a transmission electron microscope (TEM), and an elemental analyzer, it can be seen that this AMD catalyst is a low-cost, efficient, and environmentally benign heterogeneous catalyst for the aerobic selective oxidation of HMF to DFF in a one-pot technique. These research results may provide guidance for the development of more efficient catalysts for the future industrial production of high-value added DFF.
  • Researchpp 4667-4678Xu, H., Luo, J., Gao, Q., Zhang, S., and Li, J. (2014). "Improved water resistance of soybean meal-based adhesive with SDS and PAM," BioRes. 9(3), 4667-4678.AbstractPDF
    In a previous study, a soybean meal-based adhesive was developed by mixing soybean meal flour with a self-made cross-linking agent. The objective of this study was to investigate the effects of retention agents on the properties of the adhesive. Soybean meal flour (together with a cross-linking agent) and two kinds of additives (SDS and cationic PAM) were used to develop the soybean meal-based adhesive. The water resistance of the adhesive was measured by testing the wet shear strength of the resulting three-ply plywood samples and the residual rate of the different adhesives themselves. The apparent viscosities of the adhesives were also measured. Cross sections of the cured adhesives were imaged with a scanning electron microscope (SEM). Results showed that adding 0.5% SDS to the adhesive formulation improved its wet shear strength by 38.6%, from 0.83 to 1.15 MPa, and increased the residual rate by 1.3%, from 76.5 to 77.5%. Adding 0.01% PAM improved the water resistance of the adhesive by 38.6%, from 0.83 to 1.15 MPa, and increased the residual rate by 2.2%, from 76.5 to 78.2%. Adding 0.2% SDS and 0.01% PAM together improved the water resistance of the adhesive by 55.4%, from 0.83 to 1.29 MPa. The plywood bonded with the soybean meal/SDS/PAM adhesive met interior plywood requirements. SEM results showed fewer holes and cracks on the cross section of the cured adhesive with the addition of SDS and PAM.
  • Researchpp 4679-4689Fan, H., Xu, B., Liu, J., and Zhang, C. (2014). "Effect of starch dosage on the properties of modified ground calcium carbonate," BioRes. 9(3), 4679-4689.AbstractPDF
    Ground calcium carbonate (GCC) was modified with a starch/sodium stearate complex and used to prepare different coating weights by controlling the starch dosages. Modified GCC was characterized by scanning electron microscopy (SEM) and particle size analysis. The effects of starch dosage (based on the dry weight of GCC) on the size of modified GCC, the coating weight of modified GCC, and the utilization rate of starch were evaluated. Four kinds of modified GCC with different coating weights obtained by controlling the starch dosage were studied in the last part of this paper. The starch dosage was found to play an important role in the coating weight of starch/sodium stearate complex used in preparing the modified GCC and the utilization rate of starch, but did not have as much of an effect on the size of modified GCC. The higher coating weight was beneficial for retention of the filler retention and for enhancing paper strength properties at the same ash content. The higher coating weight, however, caused a decrease in the paper ash content at the same initial added filler.
  • Researchpp 4690-4702Lin, T., Li, X., Xu, Y., Yin, X., Zhang, D., and Tian, Y. (2014). "Efficient desilication by adsorption with aluminum salt-modified bentonite from green liquor," BioRes. 9(3), 4690-4702.AbstractPDF
    The objective of this work was to investigate the possibility of using Na-bentonite as a raw material to produce aluminum salt-modified bentonite (AlMB) for desilication of green liquor. Batch experiments were carried out by varying the experimental parameters to find the optimum conditions. The optimum adsorbent dose was 20 g/L. The maximum adsorptions of 96.37% and 87.22% took place at pH 7.4 when the initial concentrations of silicate in green liquor were 4 and 6 g/L, respectively. The kinetic models showed that the process included physical adsorption and chemical adsorption. Finally, this study showed that the extent of desorption was 56.78% for silicate after desorption of AlMB in 2 M NaOH solution. The AlMB is an efficient and novel adsorbent for desilicating that can provide a good reference for the “silicon influence” in a papermaking mill.
  • Researchpp 4703-4709Liu, M., and Hui, L. (2014). "Acetic acid catalyzed steam explosion for improving the sugar recovery of wheat straw," BioRes. 9(3), 4703-4709.AbstractPDF
    Acetic acid-catalyzed steam explosion pretreatment was applied to wheat straw at temperatures of 190 and 210 °C for 2, 6, and 10 min of residence time. The effects of pretreatment conditions on the total gravimetric recovery, hemicellulose sugars, glucose content, and yield of the enzymatic hydrolysis of cellulose were studied. The results indicated that the total gravimetric recovery decreases while the solubility of hemicellulose and the yield of cellulose enzymatic hydrolysis increase as the pretreatment severity increases. Pretreatment at 190 °C with a 2-min residence time resulted in the highest total gravimetric recovery, 58.9%. The optimum defiberation, glucose content, and enzymatic hydrolysis yields of 70.4 and 79.6%, respectively, occurred following pretreatment at 210 °C with a 10-min residence time. The optimal pretreatment condition was determined to be 190 °C for 10 min. Under the optimum conditions, the recovery yield of all sugars reached 42.7%. This pretreatment resulted in the highest recovery yield of all sugars.
  • Researchpp 4710-4721Djuned, F. M., Asad, M., Mohamad Ibrahim, M. N., and Wan Daud, W. R. (2014). "Synthesis and characterization of cellulose acetate from TCF oil palm empty fruit bunch pulp," BioRes. 9(3), 4710-4721.AbstractPDF
    Cellulose acetate (CA) was successfully synthesized by the acetylation of TCF cellulose pulp from oil palm empty fruit bunches (OPEFB) at room temperature, using acetic anhydride as the acetylating agent and acetic acid as the solvent in the presence of sulfuric acid/sodium bisulfate as catalysts. Degree of substitution (DS) was controlled by the variables of acetylation time and acetic anhydride to cellulose ratio, under the heterogeneous state. The product (CA) obtained was characterized through Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicate that the CA obtained has characteristics similar to commercial CA, and DS is significantly dependent on acetylation time and the acetic anhydride-to-cellulose ratio.
  • Researchpp 4722-4728Xu, W., Shi, J., and Wang, S. (2014). "Damage mode and failure mechanism of starch-based aqueous polymer isocyanate plywood bonded structure," BioRes. 9(3), 4722-4728.AbstractPDF
    Aging means that a polymer material’s performance gradually deteriorates, with the loss of use value due to the comprehensive effect of internal and external factors. In this work, a starch-based aqueous polymer isocyanate (API) adhesive joint structure of crosslinking in bonding interface was investigated. The compression shear strength was recognized as a key evaluation index, and the hygrothermal aging experiment tests were accelerated to study the damage mode and failure mechanism of the glue joint structure. The results showed that the adhesive properties of fracture were ductile fracture, and with an increase of aging time, the damage mode of the bonding was transformed from a cohesion damage mode to a cohesion damage with interface damage mode. In the early stages of the aging tests, the effect of temperature on the compression shear strength was most important; however, with the increase of aging time, the effect of humidity became most important.
  • Researchpp 4729-4740Vanhatalo, K. M., and Dahl, O. P. (2014). "Effect of mild acid hydrolysis parameters on properties of microcrystalline cellulose," BioRes. 9(3), 4729-4740.AbstractPDF
    This work presents a techno-economic analysis of two modelled microcrystalline cellulose (MCC) production facilities, a stand-alone mill, and a mill integrated into a chemical pulp mill, with annual production levels of 30,000 tons/year. These results indicate that both options can be very profitable when the return on investment and the added value of the purchased chemical pulps are used as indicators. However, the integration of MCC production will yield about 19% greater net profit than the non-integrated alternative. Integration also reduces the economic risk of investment, since operation of the MCC plant can be halted for maintenance and chemical pulp can be produced in a normal manner.
  • Researchpp 4741-4755Vanhatalo, K. M., Parviainen, K. E., and Dahl, O. P. (2014). "Techno-economic analysis of simplified microcrystalline cellulose process," BioRes. 9(3), 4741-4755.AbstractPDF
    This work presents a techno-economic analysis of two modelled microcrystalline cellulose (MCC) production facilities, a stand-alone mill, and a mill integrated into a chemical pulp mill, with annual production levels of 30,000 tons/year. These results indicate that both options can be very profitable when the return on investment and the added value of the purchased chemical pulps are used as indicators. However, the integration of MCC production will yield about 19% greater net profit than the non-integrated alternative. Integration also reduces the economic risk of investment, since operation of the MCC plant can be halted for maintenance and chemical pulp can be produced in a normal manner.
  • Researchpp 4756-4763Herold, N., Lenz, C., and Pfriem, A. (2014). "Changes in cell wall dimensions during the different stages of furfuryl alcohol modification," BioRes. 9(3), 4756-4763.AbstractPDF
    Furfuryl alcohol modification of wood is a well-known process for wood property enhancement. The present project focuses on veneer molding for high-value applications using the plasticizing effect of furfuryl alcohol. Adding maleic anhydride to furfuryl alcohol leads to an acid-catalyzed polymerization of furfuryl alcohol at elevated temperatures, fixing the shape of the veneer. In contrast to water or water vapor treatment, furfuryl alcohol-modified cell walls face a lower degree of shrinkage due to the polymer formation and possibly experience less drying-induced cracks. Earlier studies show a distinct influence of maleic anhydride on the curing of furfuryl alcohol. To determine the impact of different maleic anhydride contents on the polymer formation and the corresponding shrinkage of wood cell walls, microscopic studies were carried out on various maple microtome sections (Acer sp.), i.e., when dry, water-impregnated, after furfuryl alcohol impregnation, and after curing at elevated temperatures. At each state, the cell walls of 30 appointed early wood cells were determined by cell wall area measurements. The lowest shrinkage of impregnated samples was realized by using 10 wt% maleic anhydride in the impregnation solution and after 48 h soaking. Here, cell wall shrinkage could be reduced by approx. 42.6% compared to water-impregnation.
  • Researchpp 4764-4774Santos, A. J. A., Anjos, O., Morais, M. C., Diogo, G., Simões, R., and Pereira, H. (2014). "Characterization of cypress wood for kraft pulp production," BioRes. 9(3), 4764-4774.AbstractPDF
    Wood samples of Cupressus arizonica, C. lusitanica, and C. sempervirens were evaluated for chemical, anatomical, and pulp characteristics as raw material for pulp production. Two 17-year-old trees per species were harvested, and wood samples were taken at a height of 2 m. Wood chips from Pinus pinaster (Portugal) and P. sylvestris (Finland) were used as references. C. arizonica differed from C. lusitanica and C. sempervirens with significantly lower (p < 0.05) tracheid diameter and wall thickness in the earlywood. The total extractives contents were 3.9%, 3.3%, and 2.5% for C. lusitanica, C. sempervirens, and C. arizonica, respectively, lower than the 5.1% for P. pinaster and 4.5% for P. sylvestris. Klason lignin content ranged from 33.0 to 35.6%, higher than the 28.0 to 28.7% for the pinewoods. The kraft pulp yields for C. arizonica, C. lusitanica, and C. sempervirens were 37.7%, 36.7%, and 38.7%, respectively, with kappa numbers of 32.0, 31.6, and 28.7, respectively; the yield values were 40.8% and 42.8%, with kappa numbers of 23.4 and 21.0, for P. pinaster and P. sylvestris, respectively. The cypress species are clearly different from pine in relation to wood pulping behavior. Among the cypress, C. sempervirens provided the best pulping results.
  • Researchpp 4775-4783Li, H., Sun, H., Pu, L., and He, Z. (2014). "Stellera chamaejasme roots as raw material for pulp production," BioRes. 9(3), 4775-4783.AbstractPDF
    Cellulosic pulps were prepared from Stellera chamaejasme roots using soda, soda-anthraquinone (soda-AQ), and kraft pulping processes. S. chamaejasme is composed of 73.5% holocellulose, 39.7% α-cellulose, and 17.6% lignin, similar to wheat straw and other non-wood plant materials. The ethanol–benzene extractives content of 9.2% is higher than other non-woods. The conditions used for all pulping experiments were as follows: a liquid/solid ratio of 5:1; a time-to-maximum temperature of 100 min; a maximum temperature of 160 °C; and a time-at-maximum temperature of 50 min. The results showed that the pulp yield was 31.27 to 36.83%, the kappa number was 16.32 to 19.42, and the pulps’ intrinsic viscosity was 854 to 976 mL/g. Tear index, tensile index, burst index, and brightness of the papers made from the above unbleached pulps were 12.60 to 13.62 mN•m2/g, 20.57 to 22.56 mN/g, 2.16 to 2.38 kPa•m2/g, and 15.3 to 18.3%, respectively.
  • Researchpp 4784-4807Yilgor, N., Köse, C., Terzi, E., Figen, A. K., Ibach, R., Kartal, S. N., and Pişkin, S. (2014). "Degradation behavior and accelerated weathering of composite boards produced from waste Tetra PakAbstractPDF
    Manufacturing panels from Tetra Pak® (TP) packaging material might be an alternative to conventional wood-based panels. This study evaluated some chemical and physical properties as well as biological, weathering, and fire performance of panels with and without zinc borate (ZnB) by using shredded TP packaging cartons. Such packaging material, a worldwide well-known multilayer beverage packaging system, is composed of cellulose, low-density polyethylene (LDPE), and aluminum (Al). Panels produced from waste TP packaging material were also examined by FT-IR to understand the fungal deterioration and extent of degradation after accelerated weathering. Before FT-IR investigations, panel specimens were ground under nitrogen atmosphere due to non-uniformity of the composite material. The FT-IR results showed that fungal degradation occurred in the natural polymer of the panel matrix. Although the natural polymer is mostly composed of cellulose, there were also small amounts of polyoses and lignin. It was seen that especially polyose and lignin bands in FT-IR spectra were affected more than cellulose bands by fungal attack. No changes were observed by the fungi in the plastic component (LDPE) of the matrix; however, LDPE seemed more sensitive to weathering than cellulose. Incorporation of ZnB at loading level of 1% (w/w) did not contribute fire performance of the panels when compared to control panel specimens, while a loading level of 10% improved fire performance considering test parameters such as mass loss, ignition time and peak heat release rate.
  • Researchpp 4808-4820Gašparík, M., and Barcík, S. (2014). "Effect of plasticizing by microwave heating on bending characteristics of beech wood," BioRes. 9(3), 4808-4820.AbstractPDF
    This paper reports the bending strength and maximum deflection after plasticizing beech wood by microwave heating. Previous work by the authors confirmed that microwave heating resulted in plasticizing of beech wood, which greatly affected its deformation when loaded by compression. This work complements the overall analysis of the behavior of microwave-plasticized wood during its bending. Bending strength and maximum deflection were investigated on beech samples immediately after plasticizing by microwave heating. Static bending test with three-point flexural test was used. While plasticizing time and moisture content had an important influence on the bending strength, the device power had no appreciable effect. Plasticizing time had a significant influence on the maximum deflection, while the moisture content and device power had no substantial influence.
  • Researchpp 4821-4833Zhang, Z.-G., Song, R.-H., Hu, G.-L., and Sun, Y.-Y. (2014). "Thermal stability and degradation of poly (lactic acid)/hexamoll® DINCH/montmorillonite composites," BioRes. 9(3), 4821-4833.AbstractPDF
    The effects of the plasticizer 1,2-cyclohexane dicarboxylic acid diisononyl ester (Hexamoll® DINCH) on the thermal stability and degradation of poly (lactic acid) were investigated and compared with tributyl citrate and montmorillonite. A series of poly (lactic acid) composites were prepared via melt blending before being hot pressed into 0.3 mm films. Along with the increase of the content of MMT, the agglomeration degree rise and the MMT content for this study was determined. The addition of Hexamoll® DINCH could efficiently decrease the Tg of PLA and improve the crystallinity of poly (lactic acid) composites. The addition of DINCH or TBC could deteriorate the thermal stability of PLA composites. The addition of montmorillonite could improve the thermal stability of PLA/TBC and PLA/DINCH composites. The kinetic parameters including activation energy of decomposition (E), reaction order (n), and pre-exponential factor (lnA) of PLA/DINCH/MMT composites are 180.2 kJ/mol, 0.863, and 36.8, respectively by using Freeman-Carroll method.
  • Researchpp 4834-4843Zhu, X., and Liu, Y. (2014). "Detection and location of defects in laminated veneer lumber by wavelet package analysis," BioRes. 9(3), 4834-4843.AbstractPDF
    Large numbers of vibration signals of wood-based panels are unsteady and complicated, which means that detection can be difficult. The wavelet transform is an effective method to detect these signals, which are otherwise difficult to detect using the Fast Fourier Transform (FFT). This paper presents a study on nondestructive detection of bubble defects seen in poplar laminated veneer lumber (LVL) using a combination of modal analysis and wavelet transform. The energy spectrum of wavelet packet decomposition due to a vibration signal is investigated. The vibration nondestructive test is used to study the relationship between bubble and changes of LVL physical properties. Results show that a bubble defect leads to a variation of energy dissipation in LVL vibration, and it is mode-dependent. For relatively small bubbles, the bubble-induced changes in natural frequencies are too small to be detected by the nondestructive method. However, by analyzing the energy spectrum of wavelet packet decomposition, smaller bubbles can be detected using the nondestructive vibration signals. The position and degree of defects can be ascertained by the wavelet packet energy curvature method at the same time.
  • Researchpp 4844-4861Olarescu, C. M., Campean, M., and Olarescu, A. (2014). "Dimensional stabilization of wood originating from small-diameter trees through heat treatment," BioRes. 9(3), 4844-4861.AbstractPDF
    Small-diameter wood resulting from thinning operations is an important secondary wood resource. Compared to wood originating from mature trees of the same species, it is less stable in shape and dimension when exposed to environmental humidity changes. To reduce its hygroscopicity and valorize this secondary wood resource in solid wood panels for outdoor use, wood samples cut from mature and small-diameter spruce, black pine, lime, and beech logs were heat-treated at 180 and 200 °C for 1 to 6 h in air at atmospheric pressure. Mass loss, swelling coefficients, and anti-swelling efficiency (ASE) were established for each wood type for a comparison between species. Mature and small-diameter wood was also compared under the influence of different temperature/time combinations. The heat treatment conditions that led to a mass loss of maximum 5% in each case were: 200 °C/3.5 h (mature spruce), 200 °C/5 h (thin spruce), 200 °C/3 h (mature pine), 200°C/3.7 h (thin pine), 200 °C/3.2 h (mature lime), 200 °C/2h (thin lime), 200°C/3 h (mature beech), and 200 °C/2.7 h (thin beech). Small-diameter spruce, pine, and lime (the soft species) recorded better dimensional stabilization than the mature wood of each species (ASEvol=49.7% compared to 39.3% for spruce, 38.6% compared to 38% for pine, 52.3% compared to 44.4% for lime), while small-diameter beech behaved differently (with ASEvol=43.5% compared to 48.5 for the mature wood).
  • Researchpp 4862-4872Liu, H.-T., and Cai, L. (2014). "Effect of sewage sludge addition on the completion of aerobic composting of thermally hydrolyzed kitchen biogas residue," BioRes. 9(3), 4862-4872.AbstractPDF
    The composting of thermal-hydrolyzed kitchen biogas residue, either with or without sewage sludge, was compared in this study. The addition of sewage sludge increased and prolonged the temperature to a sufficient level that met the requirements for aerobic composting. Moreover, after mixing the compost materials, oxygen, ammonia, and carbon dioxide levels reverted to those typical of aerobic composting. Finally, increased dewatering, organic matter degradation, and similar mature compost production were observed. Overall, the sewage sludge exhibits a potential synergistic effect to facilitate complete aerobic composting of thermal-hydrolyzed biogas residue.
  • Researchpp 4873-4887Giacobbe, S., Pepe, O., Ventorino, V., Birolo, L., Vinciguerra, R., and Faraco, V. (2014). "Identification and characterisation of a pectinolytic enzyme from Paenibacillus xylanolyticus," BioRes. 9(3), 4873-4887.AbstractPDF
    Pectinolytic enzymes play an important role in the processing of lignocellulosic materials because of their ability to improve the access of cellulases to their substrate by removing pectins. The strain Paenibacillus xylanolyticus 2-6L3 was isolated from mature compost obtained from agro-industrial wastes, and the enzyme pectate lyase from P. xylanolyticus 2-6L3, named PaenxylPel, was partially purified and subjected to structural and functional characterisation. The enzyme exhibited an optimum temperature between 60 and 70 °C and optimal pH value of 9.0 for its pectinase activity on pectin from citrus fruit. PaenxylPel showed a thermoresistance and pH resistance higher than those of other pectate lyases so far described, with half-lives of 48 and 24 h at 60 and 70 °C, respectively, a retention of around 80% of activity after 96 h at 40 and 50 °C, and a half-life of about 15 days at pH 8.0. PaenxylPel followed Michaelis-Menten kinetics toward pectin from citrus fruit, pectin from sugar beet pulp, high-ester pectin extracted from citrus peel (> 50% esterified), and polygalacturonic acid (PLA). The ability to act on both PLA and highly methylated pectins, together with a double peak in the graph of optimum pH at pH 5 and 9, suggest that pectate lyase from P. xylanolyticus shows an unusual activity, combining traits of pectate lyase and pectin lyase. This is the first manuscript on the pectinolytic activity of P. xylanolyticus.
  • Researchpp 4888-4898Sri Aprilia, N. A., Abdul Khalil, H. P. S., Bhat, A. H., Dungani, R., and Hossain, M. S. (2014). "Exploring material properties of vinyl ester biocomposites filled carbonized Jatropha seed shell," BioRes. 9(3), 4888-4898.AbstractPDF
    This study investigates the influence of carbon black from carbonized Jatropha seed shell as a filler that was obtained by furnace method at 600 °C on the material properties of vinyl ester based biocomposites. The biocomposites were characterized for mechanical, thermal, and morphological properties. The tensile strength was enhanced at 10 wt.% loading of filler material as compared to the virgin polymer and higher loading percentage. Flexural strength decreased with an increase in the carbon black loading percentage, while the tensile modulus and flexural modulus showed an opposite trend. Thermogravimetric analysis showed enhancement in the residual content of the composite materials, thereby ameliorating thermal stability. Glass transition and melting temperatures by DSC analysis were observed to increase up to 10 wt % loading of filler but to decrease subsequently at higher loading percentage. The morphological analysis showed smooth morphology with intermittent lumps of agglomeration at higher loading percentages.
  • Researchpp 4899-4907Khairunnisha, I. P. N., Bakar, E. S., Nurul Azwa, A., and Choo, A. C. Y. (2014). "Effect of combination oven and microwave heating in the resin semi-curing process on the physical properties of 'Compreg' OPW," BioRes. 9(3), 4899-4907.AbstractPDF
    Oil palm wood (OPW) is still difficult to utilize efficiently due to its low strength, non-durability, low dimensional stability, and poor machinability. This study was conducted to investigate semi-curing of OPW with low-molecular weight phenol formaldehyde (Lmw-PF) by a combination of oven and microwave heating. Four main processes in a modified compreg method were used, i.e. drying, impregnation, resin semi-curing heating, and hot-pressing densification. Heating type had a significant effect on the physical properties of treated OPW. The combination of the heating methods used a much shorter time compared to heating by oven only, where over 24 to 30 h were needed to dry the treated OPW.
  • Researchpp 4908-4923Riedl, B., Angel, C., Prégent, J., Blanchet, P., and Stafford, L. (2014). "Effect of wood surface modification by atmospheric-pressure plasma on waterborne coating adhesion," BioRes. 9(3), 4908-4923.AbstractPDF
    In this study, the effect of an atmospheric-pressure plasma treatment on the surface properties of sugar maple (Acer saccharum March.) and black spruce (Picea mariana (Mill.) was analyzed by contact angle measurement and a water-based coating pull-off testing. The plasma gases used were Ar, N2, CO2, and air. It was found that the wettability with water and the coating adhesion of maple and spruce can be highly influenced by the nature of the plasma gas used and the plasma treatment time. For example, in the case of sugar maple, coating adhesion increased by 66% after 1.5 s of exposure to argon plasma. Repetition of the contact angle measurement one and two weeks after the initial plasma treatment showed that the plasma-induced modification is not permanent. Improvements in wettability and adhesion were also obtained with simpler, cheaper air plasmas, a result promising for the development of advanced plasma reactors operating at atmospheric pressure, specially designed for the wood industry.
  • Researchpp 4924-4933Xiao, N., Zheng, X., Song, S., and Pu, J. (2014). "Effects of complex flame retardant on the thermal decomposition of natural fiber," BioRes. 9(3), 4924-4933.AbstractPDF
    Natural fiber is a renewable resource characterized by its low cost and environmental friendliness. However, flame retardant properties are one of the biggest limitations for the preparation of composite materials that need to be improved. In this work, a novel complex flame retardant consisting of aluminum hydroxide (ALH) and decabromine diphenyl oxide (PBDE) was proposed to inhibit the thermal decomposition. Flame-retarding paper was made from softwood pulp and complex flame retardant. The thermal properties of the flame retardants were studied using thermogravimetric analysis (TGA). The mechanical properties of paper treated at different temperatures were tested, while the surface characteristics of natural fiber were detected by a scanning electron microscope (SEM) and atomic force microscope (AFM); their specific surface areas were also measured. The optimum value of aluminum hydroxide to decabromine diphenyl oxide was 3 to 1, added at 70% based on dried natural fiber. It also had good flame retardant performance and mechanical properties at 200 °C for 5 min; meanwhile, the tensile index of the handsheet was 82.5 Nm/g, and the specific surface area was 0.414 m2/g.
  • Researchpp 4934-4945Wang, M., Wang, X., Li, L., and Ji, H. (2014). "Fire performance of plywood treated with ammonium polyphosphate and 4A zeolite," BioRes. 9(3), 4934-4945.AbstractPDF
    Plywood samples treated with ammonium polyphosphate (APP) and 4A zeolite were prepared to investigate the effect of zeolite on wood’s burning behavior using a cone calorimeter under a heat flux of 35 kW/m2. Results showed that APP decreased the heat release rate (HRR), total heat release (THR), and mass loss rate (MLR) of treated plywood. However, APP significantly increased the total smoke release (TSR) and carbon monoxide (CO) yield. The addition of 4A zeolite reduced the HRR, peak HRR, and THR of the plywood treated with only APP. The second HRR peak in a typical plywood curve diminished with the addition of as little as 2% 4A zeolite. The average specific extinction area (ASEA) and CO yield decreased significantly with the presence of zeolite in the APP. The ignition time did not change significantly and the TSR increased when zeolite was present. Thus, a suitable amount of 4A zeolite works synergistically with APP in promoting flame retardancy in flame retardant plywood.
  • Researchpp 4946-4957Tang, C.-z., Tao, H.-x., Zhan, X.-q., and Xie, X.-a. (2014). "Mechanism of esters formation during cellulose liquefaction in sub- and supercritical ethanol," BioRes. 9(3), 4946-4957.AbstractPDF
    Cornstalk cellulose was liquefied in sub- and supercritical ethanol using an autoclave at 320 °C with 160 mL of ethanol. The effects of reaction time on esters formation during cellulose liquefaction were investigated. The yield of esters was 10.0% at 30 min, increasing to 19.1% after 60 min. Ethanol favored esters formation from cellulose liquefaction. The liquid products at different reaction time were analyzed by FT-IR and GC/MS. The results showed that many free radicals were produced in sub-/super-critical ethanol interactions. Cellulose was converted to active cellulose, which was transformed into large molecular acids by dehydration, decomposition, ring-opening reactions, isomerization, and aldol condensation, and then formed ethyl esters such as ethyl lactate by esterification. In addition, ethyl esters were decomposed to acids, alcohols, and other compounds with increasing reaction time in the presence of ethanol free radicals. Using these results, a reaction network for the formation of ethyl esters from cellulose in sub- and supercritical ethanol was proposed.
  • Researchpp 4958-4970Lehto, J., Alén, R., and Malkavaara, P. (2014). "Multivariate correlation between analytical data for various organics dissolved during autohydrolysis of silver birch (Betula pendula) chips and treatment conditions," BioRes. 9(3), 4958-4970.AbstractPDF
    Autohydrolysis pre-treatments were performed for the production of hemicellulose-rich autohydrolysates from silver birch (Betula pendula) chips prior to chemical pulping. Pre-treatment conditions were varied with respect to time (from 30 to 120 min) and temperature (130 and 150 °C), covering a P-factor range from 10 to 238. Hydrolysates were analyzed in terms of carbohydrates, lignin, volatile organic acids, and furanoic compounds. The analytical data were subjected to various chemometric techniques to establish the relationships between dissolved organic components, hardwood and softwood used in the experiments, and applied pre-treatment conditions. Using this method, differences between the wood species could be clearly seen, and a relatively accurate model for the autohydrolysis of birch chips was developed.
  • Researchpp 4971-4980Han, S., Fang, G., Li, S., Liu, G., and Jiang, G. (2014). "Cu(II) ion adsorption onto hydroxymethylated lignin-chitosan crosslinked membrane," BioRes. 9(3), 4971-4980.AbstractPDF
    A crosslinked chitosan membrane (I) and a hydroxymethylated lignin-chitosan crosslinked membrane (II) were prepared using glutaraldehyde as the crosslinking agent. Fourier transform infrared spectroscopy (FTIR) was used to identify the chemical structures of the crosslinked membranes and the presence of an absorption peak at 1515 cm-1 indicated the presence of lignin. Scanning electron microscope (SEM) images revealed that membrane (I) possessed a smooth surface, while membrane (II) exhibited a homogeneous embossed surface without any agglomeration. The Cu(II) ion adsorption properties of both membranes were analyzed. The results indicated that the static adsorption capacities of membranes (I) and (II) were 195 mg Cu(II)/cm2 and 275 mg Cu(II)/cm2, respectively, and their dynamic chelation capacities were 2.89 mg Cu(II)/cm2 and 4.59 mg Cu(II)/cm2, respectively. Membrane (I) was suitable only for use in aqueous solutions with pH values of 3.5 to 9.0, while membrane (II) maintained its shape even in concentrated hydrochloric acid or 1 M NaOH solution. The Cu(II) ion absorption properties and resistance to acid and alkali of membrane (II) were superior to those of membrane (I), indicating that hydroxymethylation of the lignin-chitosan crosslinked membrane is worthy of further investigation.
  • Researchpp 4981-4992Li, D., Tian, Y., and Qiao, Y. (2014). "Forming active carbon monoliths from H3PO4-loaded sawdust with addition of peanut shell char," BioRes. 9(3), 4981-4992.AbstractPDF
    Peanut shell char (PSC) was converted into active carbon monoliths (ACMs) by adding a binder that was easy to make. The conversion process involved adding the PSC into H3PO4-loaded sawdust, extruding the mixture, and finally heating the resulting monoliths for different times. The properties of the resulting ACMs were investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared analysis, nitrogen adsorption-desorption, X-ray diffraction, and thermogravimetric analysis. The H3PO4-loaded sawdust could be used as a binder for converting powdered PSC into well-shaped ACMs without visual cracks. The resulting ACMs maintained their monolithic shape, even in water. The ACMs showed a much higher specific surface area (SSA, 850 to 915 m2/g) than the PSC (105 m2/g). The largest SSA (915 m2/g) was achieved by activation for 50 min. Increasing the activation time decreased the SSA and apparent density, but only slightly impacted the carbon structure. This research might lead to value-added conversion of bio-chars.
  • Researchpp 4993-5006Li, K., Chen, H., Yu, H., Zhu, H., Mao, Q., Ma, X., Zhao, Z., and Xiao, T. (2014). "Study on the comprehensive utilization of bitter almond shell," BioRes. 9(3), 4993-5006.AbstractPDF
    A comprehensive process was developed to make full use of the solid and liquid products during the production of activated carbon. Almond shell waste was modified with phosphoric acid and thermally treated to give activated carbon. Wood vinegar was generated and collected within the temperature range of 90 to 500 °C, and the maximum amount of the wood vinegar was in the range of 170 to 370 °C, which also gave the strongest anti-pathogens activities with the lowest pH and the highest organic acid content. The remaining residue after wood vinegar generation was further calcined in inert atmosphere to obtain high surface area activated carbon. The pre-treatment of almond shell with H3PO4 leads to the higher surface area, but H3PO4 solution with concentration more than 40% does not increase the surface area further. The impregnation of H3PO4 helps the formation of pores in the almond shell during the calcination, and gives higher iodine number and methylene blue sorption capacity of the resultant activated carbon materials.
  • Researchpp 5007-5023Hassel, B. I., Trey, S., Leijonmarck, S., and Johansson, M. (2014). "A study on the morphology, mechanical, and electrical performance of polyaniline-modified wood - a semiconducting composite material," BioRes. 9(3), 5007-5023.AbstractPDF
    This study investigated the morphology, electrochemical modification with respect to the wood fiber direction, and mechanical properties of wood modified by in situ polymerization with polyaniline (PANI). This polymerization formed a composite material with applications as an anti-static, electromagnetic, anti-corrosion, and heavy metal purifying materials. The polymer was found throughout the entire structure of the wood and was quantified within the wood cell wall and middle lamella by SEM-EDX. The presence of PANI affected the conductivity of the composite specimens, which was found to be higher in the fiber direction, indicating a more intact percolation pathway of connected PANI particles in this direction. The PANI modification resulted in a small reduction of the storage modulus, the maximum strength, and the ductility of the wood, with decreases in the properties of specimens conditioned in an environment above 66% relative humidity. The in situ-polymerized PANI strongly interacted with the lignin component of the veneers, according to the decrease in the lignin glass transition temperature (Tg) noted in DMA studies.
  • Researchpp 5024-5033Lin, B., He, B., Liu, Y., and Ma, L. (2014). "Correlation analysis for fiber characteristics and strength properties of softwood kraft pulps from different stages of a bleaching fiber line," BioRes. 9(3), 5024-5033.AbstractPDF
    During sequential bleaching operations, pulp fiber properties are gradually changed due to mechanical and chemical treatments. In this study, the correlations between pulp or fiber properties such as kappa number, viscosity, total charge, fiber length, and zero-span tensile strength as well as Scott bond of elemental chlorine free (ECF) bleached softwood kraft pulps was investigated. The influence of zero-span tensile strength and Scott bond on tensile and tear strength was also discussed. The Scott bond and zero-span tensile strength showed a strong logarithmic correlation with pulp kappa number and pulp viscosity, while the regression coefficient for Scott bond was negative. An overall deterioration of paper tensile and tear strength from pulps whether beaten or not were observed along the multi-stage ECF bleaching operations. Changing contributions to sheet tensile or tear strength could be mostly attributed to changes in zero-span tensile strength rather than Scott bond during ECF bleaching.
  • Researchpp 5034-5044Karliati, T., Febrianto, F., Syafii, W., Wahyudi, I., and Wistara, I. N. J. (2014). "Gutta-percha-based adhesive for laminated wood production," BioRes. 9(3), 5034-5044.AbstractPDF
    The characteristics of gutta-percha (i.e., chemical compound and melting and glass transition temperatures) and the performance of laminated wood (i.e., moisture content, density, shear strength, and delamination ratio) prepared from sengon wood (Paraserianthes falcataria L. Nielsen) bonded with a gutta-percha-based adhesive were investigated. The gutta-percha-based adhesive was prepared by modification of gutta-percha with 5% maleic anhydride (MAH) and 0.75% benzoyl peroxide (BPO) at various gutta-percha to toluene ratios (w/w) (i.e.,15:85; 17.5:82.5; 20:80; and 22.5:77.5), followed by heating at 70 °C in a water bath for 10 min. Laminated wood was manufactured using both modified and unmodified gutta-percha-based adhesives at 250 gm-2 of glue spread and clamped for 24 h. Terpenes, especially 1,3 butadiene, 2-methyl (CAS)-isoprene (trans 1,4- isoprene) (polyterpene), were found to be the dominant chemical component of gutta-percha. The glass transition and melting temperatures of gutta-percha were -56.75 °C and 51.67 °C, respectively. The modification of gutta-percha with MAH and BPO as an initiator resulted in improved performance for the laminated wood. Infra-red spectrometry of the modified gutta-percha-based adhesive showed a new peak at 1720 cm-1, indicating the C=O bond of MAH.
  • Researchpp 5045-5065Amodu, O. S., Ntwampe, S. K. O., and Ojumu, T. V. (2014). "Optimization by biosurfactant production of Bacillus licheniformis STK 01 grown exclusively on Beta vulgaris waste using response surface methodology," BioRes. 9(3), 5045-5065.AbstractPDF
    This work reports on the exploitation of Beta vulgaris for biosurfactant production by Bacillus licheniformis STK 01 and its optimization using statistical modeling of response surface methodology (RSM). Three variables were investigated: agro-waste concentration, pH, and temperature. The response and contour plots of the RSM showed perfect interaction among the variables, with the highest surface tension reduction of the culture medium to 30 mN/m observed at 42 °C, a pH of 8, and a substrate concentration of 4% (w/v). The biosurfactant produced demonstrated a high tendency for hydrocarbon emulsification. Furthermore, by numerical optimization techniques, the optimum conditions were found to be as follows: a pH of 6.72, an agro-waste concentration of 4% (w/v), and a temperature of 44.5 °C. The experiment conducted to validate the optimum conditions obtained showed a biosurfactant with remarkable surface activity, lowering the surface tension of the broth to 30 mN/m, when the organism was grown on B. vulgaris, and to 23.5 mN/m, when grown in glucose medium – the later representing one of the highest surface tension reductions ever reported for a biosurfactant. This study revealed, among others, that the exclusive utilization of cheap solid agro-waste without supplementation with a refined nutrient source is feasible and could ensure the economic sustainability of biosurfactant production.
  • Researchpp 5066-5072Yadav, J., Datta, M., and Gour, V. S. (2014). "Developing hydrophobic paper as a packaging material using epicuticular wax: A sustainable approach," BioRes. 9(3), 5066-5072.AbstractPDF
    There is an urgent need for a biodegradable, hydrophobic material that can be used in developing packaging materials. In this preliminary study, epicuticular wax has been extracted from the leaves of Calotropis procera and Alstonia scholaris using various solvents (i.e., ethanol, methanol, benzene, and acetone). The highest wax amounts were found to be 0.54 µg/cm2 and 0.13 µg/cm2 from Alstonia scholaris and Calotropis procera, respectively. The highest hydrophobicity (29.57%) was found to be in paper discs coated with epicuticular wax extracted with benzene from the adaxial surface of Calotropis procera.
  • Researchpp 5073-5087Pei, P., Zhang, C., Li, J., Chang, S., Li, S., Wang, J., Zhao, M., Li, J., Yu, M., and Chen, X. (2014). "Optimization of NaOH pretreatment for enhancement of biogas production of banana pseudo-stem fiber using response surface methodology," BioRes. 9(3), 5073-5087.AbstractPDF
    In this paper, the NaOH pretreatment of banana pseudo-stem fiber for biogas production was investigated using a statistically designed set of experiments. A central composite design was used to identify the optimum pretreatment condition for four factors, i.e., NaOH concentration, pretreatment temperature, pretreatment time, and fiber length, on biogas fermentation of banana pseudo-stem fiber. The best pretreatment condition was 7.8% NaOH, 0.2-cm fiber length, and a temperature of 48 °C for 3 days. NaOH pretreatment increased the biogas yield of banana pseudo-stem fiber. The highest biogas yield was 463.0 mL·g-1VSadded, which was 89.2% higher than that of the control, at 244.7 mL·g-1VSadded.
  • Researchpp 5088-5098Kubojima, Y., Suzuki, Y., and Tonosaki, M. (2014). "Effect of additional mass on the apparent Young's modulus of a wooden bar by longitudinal vibration," BioRes. 9(3), 5088-5098.AbstractPDF
    We investigated the influence of an additional mass bonded on a wooden bar on its apparent Young’s modulus based on a longitudinal vibration theory. Rectangular bars of Sitka spruce (Picea sitchensis Carr.) were used as experimental materials. After bonding an iron piece on a bar, a free-free longitudinal vibration test was performed to obtain the Young’s modulus. Modal analysis was also performed to examine the effect of a knot on the measured Young’s modulus. The Young’s modulus decreased with an increase in mass of iron pieces bonded on the specimen and that in a size of the knot, since the constants required for the frequency equation of longitudinal vibration changed due to the additional mass and the knot. An equation was developed which contains the effects of the mass and position of the iron piece on the constants. The Young’s moduli calculated by this equation resembled the values without an iron piece and the knot. Assuming a knot to be the additional mass, the estimation method used to examine the effect of a knot on the apparent Young’s modulus was proposed. The analysis showed that the higher the resonance mode and the nearer the position to an end, the more effective efforts to reduce the effect of the additional mass will be.
  • Researchpp 5099-5113Balogun, A. O., Lasode, O. A., and McDonald, A. G. (2014). "Thermo-analytical and physico-chemical characterization of woody and non-woody biomass from an agro-ecological zone in Nigeria," BioRes. 9(3), 5099-5113.AbstractPDF
    Woody (Albizia pedicellaris and Terminalia ivorensis) and non-woody (guinea corn (Sorghum bicolor)) glume and stalk biomass resources from Nigeria were subjected to thermo-analytical and physico-chemical analyses to determine their suitability for thermochemical processing. They were found to have comparably high calorific values (between 16.4 and 20.1 MJ kg-1). The woody biomass had very low ash content (0.32%), while the non-woody biomass had relatively high ash content (7.54%). Thermogravimetric analysis (TGA) of the test samples showed significant variation in the decomposition behavior of the individual biomasses. Gas chromatography/mass spectrometry (GC/MS) of fatty acid methyl esters (FAMEs) derivatives indicated the presence of fatty and resin acids in the dichloromethane (CH2Cl2) extracts. Analytical pyrolysis (Py-GC/MS) of the samples revealed that the volatiles liberated consisted mostly of acids, alcohols, ketones, phenols, and sugar derivatives. These biomass types were deemed suitable for biofuel applications.
  • Researchpp 5114-5124Kamei, I., Hirota, Y., and Meguro, S. (2014). "Direct fungal production of ethanol from high-solids pulps by the ethanol-fermenting white-rot fungus Phlebia sp. MG-60," BioRes. 9(3), 5114-5124.AbstractPDF
    A white-rot fungus, Phlebia sp. MG-60, was applied to the fermentation of high-solid loadings of unbleached hardwood kraft pulp (UHKP) without the addition of commercial cellulase. From 4.7% UHKP, 19.6 g L-1 ethanol was produced, equivalent to 61.7% of the theoretical maximum. The highest ethanol concentration (25.9 g L-1, or 46.7% of the theoretical maximum) was observed in the culture containing 9.1% UHKP. The highest filter paper activity (FPase) was observed in the culture containing 4.7% UHKP, while the production of FPase in the 16.5% UHKP culture was very low. Temporarily removing the silicone plug from Erlenmeyer flasks, which relieved the pressure and allowed a small amount of aeration, improved the yield of ethanol produced from the 9.1% UHKP, which reached as high as 37.3 g L-1. These results indicated that production of cellulase and ensuing saccharification and fermentation by Phlebia sp. MG-60 is affected by water content and benefits from a small amount of aeration.
  • Researchpp 5125-5133Li, B., Zhang, J., Ren, X. Y., Chang, J. M., and Gou, J. S. (2014)." Preparation and characterization of bio-oil modified urea-formaldehyde wood adhesives," BioRes. 9(3), 5125-5133.AbstractPDF
    Wood-derived bio-oil was used to decrease formaldehyde emissions from urea-formaldehyde (UF) resin during the process of making three-layered plywood. The obtained bio-oil urea formaldehyde (BUF) resins were characterized by their physical, chemical, and mechanical properties (e.g., viscosity, solid content, pH value, shelf life, formaldehyde emissions, and bonding strength), analyzed for their specifications, and characterized with Fourier transform infrared spectroscopy and thermogravimetric analysis. The synthesized resins were further employed to prepare the plywood with the veneers glued. The resulting BUF plywood displayed much lower formaldehyde emissions and comparable bonding strength. For the modification on formaldehyde emission of the plywood, it was concluded that the bio-oil can be used to effectively reduce formaldehyde emissions from UF wood adhesive.
  • Researchpp 5134-5146Wang, R., Fu, Y., Qin, M., Shao, Z., and Xu, Q. (2014). "Homogeneous acylation and regioselectivity of cellulose with 2-chloro-2-phenylacetyl chloride in ionic liquid," BioRes. 9(3), 5134-5146.AbstractPDF
    A cellulose acylate, cellulose-CPAC, was prepared homogeneously in the ionic liquid 1-butyl-3-methyl chloride imidazole ([Bmim]Cl) from cotton dissolving pulp. The pulp in the solvent system [Bmim]Cl/N,N-dimethyl formamide (DMF), and then reacted with 2-chloro-2-phenylacetyl chloride (CPAC) in the presence of an acid-binding agent. The effects of functional conditions including the molar ratio of CPAC/anhydroglucose unit (AGU), reaction time, reaction temperature, kind of acid-binding agent, and cellulose concentration on the degree of substitution (DS) were studied. The reactivities of the three hydroxyl groups in the homogeneous acylation of cellulose with CPAC were also investigated. The results showed that in homogeneous reaction medium, although all the C-6, C-3, and C-2 positions within the cellulose AGU could be substituted by CPAC, the reaction was quite selective for the C-6 OH. The successful synthesis of the cellulose-CPAC was confirmed by FT-IR, 1H NMR, 13C NMR, XRD, and STA. Furthermore, the acylation of cellulose with CPAC decreased the thermal stability of cellulose.
  • Researchpp 5147-5154Hamerlinski, J., and Pyr'yev, Y. (2014). "A method of minimising paper requirements for offset printing," BioRes. 9(3), 5147-5154.AbstractPDF
    The conducted study desired to increase the accuracy of estimating paper quantity requirements for printing. Changes in press construction and auxiliary equipment help reduce the total waste during production; however, typical estimation methods do not take these changes into account. By specifying the number of important job parameters and using a dimensional analysis approach, it was possible to devise a model of waste sheet quantity estimation better suited for current production practices. Using this model, it is possible to reduce the quantity of paper required for a particular print run as well as better predict the total waste sheet quantity. As a result, less paper may be ordered, stocked, and utilised in production. Using this model, a printing house may develop unique technological allowance standards for their particular substrates and products. The method of waste quantity prediction presented in this paper is also suitable for establishing a quality control system.
  • Researchpp 5155-5174Nadavala, S. K., Che Man, H., and Woo, H.-S. (2014). "Biosorption of phenolic compounds from aqueous solutions using pine (Pinus densiflora Sieb) bark powder," BioRes. 9(3), 5155-5174.AbstractPDF
    The present study describes the development of a new bioadsorbent from lignocellulosic wastes of agricultural origin. The biosorption capacity of an agricultural solid waste, pine bark (Pinus densiflora Sieb.), to remove phenolic compounds (phenol, 2-chlorophenol (2-CPh), and 4- chlorophenol (4-CPh)) from aqueous solutions under batch equilibrium conditions was investigated. The morphological characteristics of the biosorbent were evaluated by BET surface area analysis, Fourier transform infrared spectroscopy (FTIR), elemental analysis, an X-ray diffractometer (XRD), and a scanning electron microscope (SEM). Batch experiments were conducted to investigate the effect of initial pH (2 to 10), contact time, initial concentration of adsorbate (50 to 200 mg/L), and biosorbent dosage. The biosorption of phenolic compounds decreased with increasing pH, and the highest biosorption capacity was achieved at a pH of 6.0. Biosorption equilibrium was established in 120 min. The biosorption equilibrium data were fitted and analyzed with Langmuir, Freundlich, and Dubinin-Radushkevich isotherm equations, as well as four adsorption kinetic models. The kinetics data fitted well into the pseudo-second-order kinetic model, with a correlation coefficient greater than 0.993. The maximum monolayer biosorption capacity of pine bark for phenol, 2-CPh, and 4-CPh was found to be 142.85, 204.08, and 263.15 mg/g, respectively, as calculated by the Langmuir model at 30 ± 1 °C. Pine bark could be used as a new effective, low-cost biosorbent material with good uptake capacity and rapid kinetics for the removal of phenolic compounds from aqueous media.
  • Researchpp 5175-5183Zhang, M., Hao, N., Song, S., Wang, J., Wu, Y., and Li, L. (2014). "Investigation of the mixed refining of a novel fly ash-based calcium silicate filler with fiber," BioRes. 9(3), 5175-5183.AbstractPDF
    In this paper, the mixed refining of fiber and a novel fly ash-based calcium-silicate (FACS) filler is proposed as a new filler application method, as it has some advantages over the traditional filling method. Paper produced using this filler application technique exhibits improved strength and optical properties but reduced bulk. SEM images were obtained to show the FACS filler-fiber composite structure that formed during the mixed refining process. Two models were proposed to describe the mechanism by which the mixed refining process improved the paper properties. Mixed refining can decrease the size of FACS particles, especially if the filler/fiber ratio is low. It was suggested that handsheets filled with small FACS particles had low bulk, which was beneficial for increasing the interfiber H-bonding. Decreasing the filler/fiber ratio improved the paper strength and optical properties at the expense of some bulk, a loss which varied depending on filler content.
  • Researchpp 5184-5197Toong, W., Ratnasingam, J., Mohamad Roslan, M. K., and Halis, R. (2014). "The prediction of wood properties from anatomical characteristics: The case of common commercial Malaysian timbers," BioRes. 9(3), 5184-5197.AbstractPDF
    This study established a predictive relationship between the material properties and the anatomical characteristics of common commercial Malaysian timbers. Anatomical databases were analysed using a one-way analysis of variance (ANOVA), a Duncan test, and the Spearman and Pearson correlation tests, and then modelled using multiple regression (stepwise method with constant excluded). The correlation tests revealed that the properties and anatomical characteristics of the wood were strongly correlated. The predictability of the resulting equation models was quite high. The equation models were able to relate various anatomical characteristics to wood texture, porosity, density, radial shrinkage, modulus of elasticity, and compression parallel to grain. This finding suggests that the relationship between the properties and the anatomical characteristics of wood can be described successfully using multiple regression equation models.
  • Researchpp 5198-5207Wu, C., Zhang, K., Chen, J., and Li, S. (2014). "Effect of cellulase and protease pretreatment on dewaterability of waste activated sludge from paper mill," BioRes. 9(3), 5198-5207.AbstractPDF
    The feasibility of cellulase and protease pretreatment to improve the dewaterability of waste activated sludge from papermaking (WASP) was evaluated. Dewatering properties such as capillary suction time (CST), dry solids content of the sludge cakes from the specific resistance of filtration (SRF), and compression were measured to quantify the effects of cellulase and protease in sludge dewatering. The changes in the amounts of proteins (PN) and polysaccharides (PS) in tightly bound extracellular polymeric substances (TB-EPS) was found to be the most important parameter with respect to sludge dewatering. Further study, through nitrogen adsorption, verified the large change in the average pore width and surface area. Therefore, in the inner structure of WASP granules are the fundamental reasons for the enhanced dewaterability.
  • Researchpp 5208-5218Bomba, J., Šedivka, P., Böhm, M., and Devera, M. (2014). "Influence of moisture content on the bond strength and water resistance of bonded wood joints," BioRes. 9(3), 5208-5218.AbstractPDF
    Bonding processes play a significant role in the wood and furniture industry. They allow for the creation of fixed joining of construction elements, creation of new materials and, last but not least, aesthetic appreciation of parts. However, the quality of bonded joints is affected by many factors, one of which is the moisture of the bonded material – wood. The main objective of this research was to determine the influence of wood moisture on the strength of bonded joints formed by polyvinyl acetate (PVAc) and polyurethane (PUR) adhesives. In current practice these adhesives are being increasingly used for their properties and zero formaldehyde content. The procedure for determining the bond strength (tensile shear strength of lap joints) corresponded to standard EN 205. It was ascertained that in addition to actual moisture of bonded wood, the quality of the joint is also affected by the environment to which the glued joint is subsequently subjected. In a normal environment, the strength of the tested joint PVAc adhesive decreases with increasing wood moisture, but it still meets the requirement of the standard. In a humid environment, the strength falls below the limit of the standardized value. In a normal environment the joint strength bonded with PUR adhesive is similar, but the decrease in strength is lower. In a humid environment it shows the highest strength at 20% wood moisture and meets the specified standard minimum strength (4 MPa). Graphs ​​were created from the measured values that clearly show the influence of wood moisture on the final bond strength of a joint.
  • Researchpp 5219-5233Yang, X., Lyu, H., Chen, K., Zhu, X., Zhang, S., and Chen, J. (2014). "Selective extraction of bio-oil from hydrothermal liquefaction of Salix psammophila by organic solvents with different polarities through multistep extraction separation," BioRes. 9(3), 5219-5233.AbstractPDF
    Bio-oil obtained from hydrothermal liquefaction of Salix psammophila is a very complicated mixture with some highly valued chemicals. In order to separate the chemicals from bio-oil, solvent extraction using nine solvents with different polarities were investigated in detail. The bio-oil extraction yield of the nine solvents were from high to low: tetrahydrofuran > toluene > ethyl acetate > acetone > ether > methylene chloride > methanol > petroleum ether > n-hexane. Based on their extraction yield, an efficient solvent combination of n-hexane, ethyl acetate, and tetrahydrofuran was used to separate the bio-oil through multistep extraction into three parts: light oil (26.13%), mid-weight oil (54.19%), and heavy oil (19.68%). These fractions were characterized by gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy, and thermogravimetric analysis. The results showed that most of the highly valued chemicals were contained in the light oil; the mid-weight oil consisted of aromatic oligomer derived from the decomposition of lignin, which could be a promising candidate for partial substitute for petroleum-asphalt binder; the heavy oil was rich in alkanes.
  • Researchpp 5234-5245Zhang, Y., Xiao, R., Gu, X., Zhang, H., Shen, D., and He, G. (2014). "Catalytic pyrolysis of biomass with Fe/La/SBA-15 catalyst using TGA-FTIR analysis," BioRes. 9(3), 5234-5245.AbstractPDF
    Biomass pyrolysis or gasification can convert low-energy density biomass into a high-energy density gaseous fuel. In this paper, pyrolysis of pine sawdust with and without the addition of a catalyst was investigated using a thermogravimetric analyzer coupled with Fourier transform infrared spectroscopy (TGA-FTIR). The effects of modified SBA-15 catalysts on the formation characteristics of CO, CO2, and CH4 were studied. The two prepared catalysts, La/SBA-15 and Fe/La/SBA-15, retained the hexagonal order of the SBA-15 material and showed high thermal stability in the temperature range of the TGA-FTIR experiments. The results showed that the pyrolysis behavior of biomass is remarkably improved in the presence of La/SBA-15 and Fe/La/SBA-15 catalysts. The modified SBA-15 materials favored thermal cracking of macromolecular substances, resulting in an apparent decrease in the tar and coke fraction, an increase in the yield of light gases, and much higher gas production. Meanwhile, a significant increase in CH4 led to a much higher energy density gaseous product.
  • Researchpp 5246-5261Muneer, F., Johansson, E., Hedenqvist, M. S., Gällstedt, M., and Newson, W. R. (2014). "Preparation, properties, protein cross-linking and biodegradability of plasticizer-solvent free hemp fibre reinforced wheat gluten, glutenin, and gliadin composites," BioRes. 9(3), 5246-5261.AbstractPDF
    The present study is aimed at evaluating the use of plant-based polymers and fibres for the production of sustainable biocomposites. For the first time, plasticiser/solvent-free hemp fibre-reinforced wheat gluten and hemp-gliadin and glutenin composites were obtained by compression moulding at different temperatures. The plasticiser/solvent-free sample preparation method developed in this study facilitated the use of a powdered protein matrix with a mat of randomly oriented hemp fibres. The tensile and protein cross-linking properties, as well as the biodegradability, were investigated. The addition of hemp fibre to the protein matrix increased the E-modulus by 20 to 60% at 130 °C. An increase in moulding temperature from 110 to 130 °C resulted in an increase in maximum stress due to the formation of intermolecular bonds between protein chains. The gliadin composites had higher E-modulus and maximum stress and showed a larger increase in protein polymerisation with increased temperature compared to the glutenin composites. A comparison of tensile properties revealed that the composites were stiffer and stronger compared to several similarly produced biobased composites. The composites were found to be fully biodegradable under a simulated soil environment after 180 days. Biocomposites produced in the present study were found to be environmentally friendly with fairly good mechanical properties.
  • Researchpp 5262-5278Chen, C., Tong, Z., Liao, D., Li, Y., Yang, G., and Li, M. (2014). "Chemical composition and antimicrobial and DPPH scavenging activity of essential oil of Toona sinensis (A. Juss.) Roem from China," BioRes. 9(3), 5262-5278.AbstractPDF
    The chemical components of essential oil of Toona sinensis leaf blades and their petioles from China were extracted by simultaneous distillation solvent extraction (SDE) and were analyzed by GC-MS. The antimicrobial and DPPH scavenging activity of the essential oil were evaluated. The results showed that there were differences in chemical compositions and content among essential oils extracted from T. sinensis in different parts and different geographical areas in China, but the main components of essential oils were sesquiterpene and sesquiterpene oxygenated compounds, accounting for 90.1% (No. 1), 92.6% (No. 2), and 80.9% (No. 3) of the relative mass fraction, respectively. T. sinensis essential oil exhibited noticeable growth inhibitory activity against the tested microorganisms. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of different essential oils against microorganisms were different. For all essential oil samples, MIC and MBC against Escherichia coli and Bacillus subtiliswere less than 25 μg·mL−1, MIC and MBC against Penicillium citrinum were 200 and 400 μg·mL−1, respectively, and MIC and MBC against Colletotrichum gloeosporioides were 50 and 200 μg·mL−1, respectively. The IM50 of DPPH scavenging for T. sinensis essential oil was less than 0.3 g DPPH per g essential oil. The results indicated that T. sinensis essential oil may be a useful natural antiseptic source from forest products.
  • Researchpp 5279-5289Liu, K., He, B., Qian, L., and Li, J. (2014). "Conducting graphite/cellulose composite film as a candidate for chemical vapor-sensing material," BioRes. 9(3), 5279-5289.AbstractPDF
    A type of conductive graphite/cellulose composite film used for chemical vapor-sensing material was prepared at room temperature in the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIm]Cl). Graphite was pretreated with both oxidation and reduction processes. Due to the use of N,N-carbonyldiimidazole (CDI), as a covalent cross-linking agent in [BMIm]Cl, there were limited chemical bonds between the graphite and cellulose. The composite film was analyzed using Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XRD). When these conducting films were exposed to certain organic vapors, their electrical resistances quickly changed, showing gas sensitivity. The percolation threshold of the conducting film was about 5 wt%. The gas-sensing behavior of these films in solvent were the opposite of those gas-sensing materials based on a non-polar polymer matrix. A typical negative vapor coefficient (NVC) was observed when the film was placed in polar organic solvents such as methanol, ethanol, and acetone.
  • Researchpp 5290-5301Eng, C. C., Ibrahim, N. A., Zainuddin, N., Ariffin, H., and Wan Yunus, W. M. Z. (2014). "Compositional and morphological changes of chemical modified oil palm mesocarp fiber by alkaline bleaching and silane coupling agents," BioRes. 9(3), 5290-5301.AbstractPDF
    In this study, the effects of chemical modifications of oil palm mesocarp fiber (OPMF) via bleaching, silane coupling agents, and combinations of the two on the composition and morphology of OPMF were investigated. The chemically modified OPMF was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The FTIR spectra showed that bleached OPMF became more hydrophilic, while silanized unbleached and silanized bleached OPMF became less hydrophilic. The TGA thermograms indicated that bleaching successfully removed hemicellulose from the OPMF, while TGA analysis showed that silanized unbleached and silanized bleached OPMF had higher thermal stabilities than unbleached or bleached OPMF. The SEM micrographs revealed that the modified OPMF surface was rougher and more porous than that of the unbleached OPMF, further indicating that OPMF was successfully modified.
  • Researchpp 5302-5310Abdolzadeh, H., Layeghi, M., Ebrahimi, G., and Ghassemie, M. (2014). "Study of stress capacity improvement of L-type joint by chemical modification of wood," BioRes. 9(3), 5302-5310.AbstractPDF
    Chemical modification of wood with the aim of improving its dimensional stability can also influence the mechanical behavior of the timber when assembled into a structure. Hence, in this study, the stress-carrying capacity of mitred and butted L-type joints constructed from furfurylated wood samples with two weight percentage gains (WPGs), i.e., 20 and 60% (low and high levels, respectively), was investigated by subjecting the specimen to a diagonal tension load. Results indicated that the bending moment resistance of both L-type joints depends on the WPG. The L-type joints’ bonded stress value with poly-vinyl acetate (PVAc) adhesive decreased with increasing WPGs. Likewise, in the case where epoxy adhesive was used for jointing, the stress capacity increased for both joints constructed with furfurylated wood. Values of tension stress in the butted joint were higher compared to the mitred one. Evaluation of shear stress parallel (׀׀ ) and perpendicular () to the grain of members jointed with PVAc adhesive demonstrated that the shear stress-carrying capacity decreases as furfurylation level increases. However, by applying epoxy adhesive for jointing, τ׀׀ and τ┴ were increased by raising the furfurylation levels.
  • Researchpp 5311-5324Zainuddin, M. F., Shamsudin, R., Mokhtar, M. N., and Ismail, D. (2014). "Physicochemical properties of pineapple plant waste fibers from the leaves and stems of different varieties," BioRes. 9(3), 5311-5324.AbstractPDF
    Pineapple agro-waste, the residue produced during harvesting or processing activities, is widely available around the world. After harvesting, most pineapple residue is disposed of and serves as fertilizer, or is burnt in an open field. However, these methods are not only ineffective, but also contribute to air pollution. The main objective of this study is to determine the physicochemical properties (i.e., cellulose, hemicellulose, lignin, proximate composition, dry matter, and nitrogen content), of leaves and stems in different varieties (MD2, Moris, and Josapine) of the pineapple plant waste. The data obtained were analyzed using thermogravimetry analysis and proximate analysis. The results showed that the stems and leaves of different varieties exhibit different percentages in lignocellulosic content (hemicellulose, cellulose, and lignin). Proximate analysis showed that nutrient contents were available in the leaves and stems of pineapple plant of different varieties.
  • Researchpp 5325-5338Shukor, H., Al-Shorgani, N. K. N., Abdeshahian, P., Hamid, A. A., Anuar, N., Rahman, N. A., Isa, M. H. M., and Kalil, M. S. (2014). "Biobutanol production from palm kernel cake (PKC) using Clostridium saccharoperbutylacetonicum N1-4 in batch culture fermentation," BioRes. 9(3), 5325-5338.AbstractPDF
    Palm kernel cake (PKC), a by-product of palm oil industry, contains glucose and mannose as hexose sugars. This study was performed to determine the feasibility of using PKC as a lignocellulosic substrate for biobutanol production by Clostridium saccharoperbutylacetonicum N1-4 in an acetone-butanol-ethanol (ABE) fermentation process. Moreover, the effect of tryptone-yeast extract-acetate (TYA) medium and P2 medium on biobutanol production was evaluated. Experimental results showed that butanol production of 3.05 g/L was obtained using mannose sugar, which was comparable to 3.61 g/L butanol production measured using glucose. Moreover, the maximum production of biobutanol (0.38 g/L) was obtained at a PKC concentration of 30%, indicating the possibility of PKC utilization in butanol production. ABE fermentation of PKC using distilled water, TYA medium, and P2 medium showed that the highest butanol production (0.26 g/L) with ABE production of 0.38 g/L was obtained when ABE fermentation was conducted in P2 medium.
  • Researchpp 5339-5348Kowaluk, G. (2014). "Properties of lignocellulosics composites containing regenerated cellulose fibers," BioRes. 9(3), 5339-5348.AbstractPDF
    The aim of the paper was to examine the application of regenerated cellulose fibers as a reinforcement material in particleboard production. Single-layer, 10 mm thick panels, with the density of 800 kg/m3 were produced with addition of regenerated cellulose fibers in the range of 0 do 15% by mass during panels’ production. The mechanical and physical parameters of the produced panels were tested, as well as work of fracture. The results showed that addition of regenerated cellulose fibers to the structure of wood-based composite did not improve their modulus of rupture, modulus of elasticity, or internal bond. The physical parameters of the produced panels (water absorptivity, swelling in thickness when soaking) also were reduced. The work of fracture of the tested panels increased with increasing content of regenerated cellulose fibers. A strong linear regression between work of fracture and regenerated cellulose fibers content was observed.
  • Researchpp 5349-5361Chuchała, D., Orlowski, K. A., Sandak, A., Sandak, J., Pauliny, D., and Barański, J. (2014). "The effect of wood provenance and density on cutting forces while sawing Scots pine (Pinus sylvestris L.),"AbstractPDF
    Several properties of wood including the cutting power requirements can be correlated to wood density. Therefore, according to the literature, the cutting power requirements (and/or cutting forces) could be computed as a function of the wood specific gravity. This research shows that such an approach, based solely on specific gravity, may be considered a rather rough and imperfect estimate of cutting power. Samples of Scots pine (Pinus sylvestris L.) wood from different provinces in Poland with varying densities were machined on a sash gang saw. The average cutting force versus average wood density (estimated with the standard gravimetric method) was calculated, and the local cutting forces correlated to the local wood density. The average values of the cutting forces measured at selected points along the sample’s length were calculated by linear regression to the X-ray absorbance (density) estimated by means of X-ray radiography.
  • Researchpp 5362-5384Shahid, S. A., Ali, M., and Zafar, Z. I. (2014). "Characterization of phenol-formaldehyde resins modified with crude bio-oil prepared from Ziziphus mauritiana endocarps," BioRes. 9(3), 5362-5384.AbstractPDF
    This study was conducted to evaluate the effects of bio-oil incorporation on properties of bio-oil-phenol formaldehyde (BPF) resol resins along with the optimization of petro-phenol substitution level. Crude bio-oil prepared from endocarp shells of Ziziphus mauritiana by direct solvolytic liquefaction (ethanol-water 1:1 wt./wt. at 300 °C) was used to partially substitute the petro-phenol (30% to 75% wt./wt.) in the resin synthesis. The modified resins were subjected to measurement of various properties, including molecular weight, pH, viscosity, density, gel/cure time, non-volatile solid content, and limiting oxygen index. Bonding performance of the BPF resins was evaluated by measuring the mechanical and hygroscopic properties of the particle boards developed using such resins. With the incorporation of bio-oil, the viscosity and molecular weight of the BPF resins increased, while the values of pH, density, non-volatile solid content, and limiting oxygen index decreased. The gel, cure, and bonding tests revealed that with the addition of more than 45% bio-oil, the gel/cure times of the BPF resins increased, while the bonding performance decreased. Petro-phenol could therefore be substituted by crude bio-oil up to 45% wt./wt. safely.
  • Researchpp 5385-5416Reeb, C. W., Hays, T., Venditti, R. A., Gonzalez, R., and Kelley, S. (2014). "Supply chain analysis, delivered cost, and life cycle assessment of oil palm empty fruit bunch biomass for green chemical production in Malaysia," BioRes. 9(3), 5385-5416.AbstractPDF
    Financial, environmental, and supply chain analyses of empty fruit bunch (EFB) biomass are needed for the development of a sustainable green chemicals industry in Malaysia. Herein, holistic analysis of the supply system and EFB life cycle cradle-to-gate are analyzed in an effort to make recommendations for the commercial-scale collection and delivery of EFB from crude palm oil (CPO) extraction facilities to biorefineries in Malaysia. Supply chain modeling tracked inputs and outputs for financial analysis. The openLCA software was used for life cycle assessment (LCA). Allocation scenarios were used to explore the impact of accounting methodologies on the competitiveness of EFB compared to other feedstocks. Sensitivity analysis on the effect of transportation distance, emission flows, and allocation methods on resulting environmental impacts were conducted. The No Burden, Economic, and Mass allocation scenarios resulted in 17, -2.3, and -265 kg CO2-eq. BD tonne-1 EFB global warming impacts (GW), respectively. Delivered cost for EFB was calculated to be approximately 45 US$ BD tonne-1. Environmental burdens were sensitive to allocation scenario, covered area, and land use change. Delivered cost was sensitive to transport distance, covered area, and yield. It was shown that there is sufficient Malaysia EFB available for between 9 and 28 biorefineries, depending upon the scale of production.
  • Researchpp 5417-5437Carrasco, J. C., Oporto, G. S., Zondlo, J., and Wang, J. (2014). "Observed kinetic parameters during the torrefaction of red oak (Quercus rubra) in a pilot rotary kiln reactor," BioRes. 9(3), 5417-5437.AbstractPDF
    The torrefaction of red oak (Quercus rubra) was performed in a pilot rotary kiln reactor, and the apparent kinetic results were compared with the results of torrefaction performed in a bench-scale fluidized reactor. Mass loss, gross calorific analyses, ultimate analyses, and proximate analyses were applied to the final torrefied material. The experimental torrefaction temperatures were 250, 275, 300, and 325 °C, and the experimental total torrefaction times were 20, 35, 50, and 80 min. A significant variation of the energy content occurred in the range of temperature between 275 and 300 °C, with the energy yield changing from 97.5% to 83.6%, respectively. The molar ratios H:C:O for the torrefied red oak presented a behavior independent of the experimental equipment when the temperature ranged between 250 and 325 °C. For the torrefaction process of red oak in the pilot rotary kiln reactor, a first-order reaction and one-step kinetic model were fitted with a maximum error of about 7.5% at 325 °C. The observed reaction rate constant (k) for the rotary reactor was 0.072 min-1 at 300 °C, which was 71% lower than the reaction rate constant for torrefied red oak in a bench-scale fluidized reactor. Arrhenius analysis determined an activation energy of 20.4 kJ/mol and a frequency factor of 5.22 min-1. The results suggest significant external heat and mass-transfer resistances in the rotary system.
  • Researchpp 5438-5447Ruayruay, W., and Khongtong, S. (2014). "Impregnation of natural rubber into rubber wood: A green wood composite," BioRes. 9(3), 5438-5447.AbstractPDF
    A green wood composite material was developed from the two environmentally friendly substrates natural rubber (cis-1,4-polyisoprene) and rubber wood (Hevea brasiliensis). Natural rubber (NR) was introduced into rubber wood by pressurization of NR latex, followed by the removal of the aqueous phase to allow only dry NR to remain inside the wood structure. Scanning electron microscopy images and the weight increase of the dry impregnated samples revealed the retention of dry NR within the rubber wood. The natural rubber enhanced the water resistance and compressive strength of the treated rubber wood.
  • Researchpp 5448-5460Li, C., Li, H., Zhang, S., and Li, J. (2014). "Preparation of reinforced soy protein adhesive using silane coupling agent as an enhancer," BioRes. 9(3), 5448-5460.AbstractPDF
    Soybean flour (SF)-based adhesives were prepared with either γ-amino, γ-glycidyl, or γ-methacryloyloxy-propyltrimethoxysilane (KH550, KH560, and KH570) silane coupling agents (SCAs) as an enhancer to explore the effect of SCA on the enhancement and mechanisms of the adhesive. Then, the shear adhesion, viscosity, solid content, and morphological properties of the modified SF adhesives were characterized in detail. The cross sections of the cured adhesives were evaluated with a scanning electron microscope (SEM). The results showed that KH560 was the most efficient SCA for improving the water-resistant bonding strength of the modified SF adhesive. With the addition of 3 wt% KH560, the water-resistant bonding strength of the sample was maximized at 0.98 MPa, meeting the requirements for interior plywood. The SEM revealed few holes and cracks, as well as a smooth surface, on the cross section of the cured KH560-modified SF adhesive, indicating that KH560 is a crosslinking agent that could enhance the water-resistant bonding strength of the resulting plywood. In the hot press process, the effects of hot press time and temperature on the water-resistant bonding strength of the adhesives were not significant.
  • Researchpp 5461-5472Ma, X., Wang, Ge, Jiang, Z., Xian, Y., and Li, H. (2014). "Comparison of bending creep behavior of bamboo-based composites manufactured by two types of stacking sequences," BioRes. 9(3), 5461-5472.AbstractPDF
    The study of viscoelastic and mechano-sorptive creep on bamboo laminated veneer lumber (BLVL) and bamboo/poplar plywood (BPP) is described in this paper. Bending creep tests parallel to the grain were carried out on two bamboo-based composites for a length of 90 days. The specimens measured 500 mm × 20 mm × 12 mm. Based on the experimental data, the creep curves of two boards were evaluated. The results are summarized as follows: (1) the anti-creep property of BLVL was better than that of BPP; (2) ; and (3) compared with the creep curve in a constant environment, the creep deformation changed more dramatically under varying environment.
  • Researchpp 5473-5479Fernandes, B. V., Zanuncio, A. J. V., Furtado, E. L., and Andrade, H. B. (2014). "Damage and loss due to Ceratocystis fimbriata in Eucalyptus wood for charcoal production," BioRes. 9(3), 5473-5479.AbstractPDF
    Eucalyptus plantation area has been increasing in Brazil, with 29% of the total plantation area being located in Minas Gerais state, which currently is being utilized primarily for charcoal production. However, diseases often increase the production costs of Eucalyptus. The objective of this study was to evaluate the effect of the fungus Ceratocystis fimbriata Ellis & Halsted on Eucalyptus wood for charcoal production. The basic density, volume, extractives, lignin, and holocellulose content of the wood were determined, as well as the gravimetric yield, volatile matter, fixed carbon, ash, and gross calorific values of charcoal. The introduction of the fungus C. fimbriata to Eucalyptus decreased the wood production and holocellulose content, but it also increased the wood’s lignin and extractives content. The chemical changes in the wood did not affect the charcoal produced. Volume of wood losses due to C. fimbriata can result in a loss of up to 3478.43 US$/ha.
  • Researchpp 5480-5487Kasmani, J. E., Samariha, A., and Nemati, M. (2014). "Effect of mixing different contents of OCC pulp on NSSC pulp strength," BioRes. 9(3), 5480-5487.AbstractPDF
    This research was conducted to study changes in mechanical properties due to mixing of old corrugated container (OCC) pulp with virgin neutral sulfite semi-chemical (NSSC) pulp. The OCC pulp was collected after removal of printing, glued parts, and unwanted additives. To prevent cutting of fibers, dedicated containers were broken down by hand before pulping. Handsheets with a base weight of 127 g/m2 were made by mixing the NSSC and OCC pulps at proportions of 60, 70, and 80 wt% of NSSC. Mechanical properties, including tensile strength, burst strength, tearing strength, corrugated medium test, and ring crush test, were evaluated using TAPPI standards. Addition of up to 30% OCC improved the tensile strength, tear strength, and burst strength of the handsheets significantly in comparison with the control sample (21, 25, and 59%, respectively). However, the corrugated medium test and ring crush test decreased by about 13 and 9%, respectively. The results of this study revealed that mixing 30 wt% OCC with NSSC yielded a higher quality paper.
  • Researchpp 5488-5500Chen, Y., Stark, N. M., Cai, Z., Frihart, C. R., Lorenz, L. F., and Ibach, R. E. (2014). "Chemical modification of kraft lignin: Effect on chemical and thermal properties," BioRes. 9(3), 5488-5500.AbstractPDF
    Esterified kraft lignins (KL) were prepared by reaction with maleic anhydride (MA), succinic anhydride (SA), and phthalic anhydride (PA) in acetone solutions. The esterified lignins were characterized using ATR-FTIR, solid state CP-MAS 13C NMR spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). PA modification resulted in the highest weight gain percent (WGP) when compared to MA and SA modifications. Spectroscopic analysis revealed decreases in hydroxyl content and increases in carbonyl (C=O) and ester groups of the modified KL as a result of esterification. The hydrophobic properties of the modified lignin increased. The MA- and SA-modified KL showed an increased thermal stability compared to unmodified KL. PA-modified lignin presented distinct thermal decomposition stages, which showed rapid degradation at lower temperature. The results of this study indicate that it is possible to change the basic properties of kraft lignin by anhydride modification to facilitate the production of high performance composites.
  • Researchpp 5501-5510Zhu, X., and Liu, Y. (2014). "Nondestructive testing and system reliability based on finite element modeling in GFRP-reinforced timber beams," BioRes. 9(3), 5501-5510.AbstractPDF
    In the past few decades, the use of glass fiber-reinforced polymers (GFRP) to enhance the strength and stiffness of timber beams has been established. Research to predict the performance of structural timber is ongoing. Nondestructive evaluation of its dynamic performance and reliability are important. A nondestructive testing method based on fast Fourier transform analysis was used to establish the dynamic modulus of elasticity of GFRP-reinforced timber beams. The results were compared to those obtained via destructive measurements of the static modulus of elasticity using a regression analysis method. Significant correlations between the dynamic modulus of elasticity (MOE) and static MOE indicate that nondestructive testing is a suitable tool for practical use. Reinforced timber beams were designed based on the measured dynamic MOE. Orthogonal theories were used to analyze the effects of the thickness, glue application, and surface area of GFRP on the MOE of reinforced timber beams. Furthermore, the system reliability of GFRP-reinforced timber beams was predicted with a finite element model. The results showed that GFRP can significantly increase the reliability of structural lumber.
  • Researchpp 5511-5528Lorbach, C., Fischer, W. J., Gregorova, A., Hirn, U., and Bauer, W. (2014). "Pulp fiber bending stiffness in wet and dry state measured from moment of inertia and modulus of elasticity," BioRes. 9(3), 5511-5528.AbstractPDF
    The bending stiffness of pulp fibers in both dry and wet states is of great importance with respect to many optical and physical paper properties. We introduce a method that evaluates fiber bending stiffness from the fibers’ Young’s modulus (E) and the area moment of inertia (I) from the fiber cross section. The values for E and I in the dry state are obtained from single fiber tensile testing and image analysis of the fiber cross section. The values for the wet state are estimated from literature results for decreasing elastic modulus due to wetting and by the measurement of swollen, freeze-dried fiber cross sections by serial sectioning. We show a comparison between the results from our method and the bending stiffness of individual fibers measured with other methods.
  • Researchpp 5529-5541Liu, C., Zhang, Y., Wang, S., Meng, Y., and Hosseinaei, O. (2014). "Micromechanical properties of the interphase in cellulose nanofiber-reinforced phenol formaldehyde bondlines," BioRes. 9(3), 5529-5541.AbstractPDF
    Lab-processed cellulose nanofibrils (CNF-L), commercial cellulose nanofibrils (CNF-C), and cellulose nanocrystals (CNC) were used in this study as reinforcing materials in phenol formaldehyde (PF) resin. The mechanical modification of adhesives and cell wall layers (S2 and compound corner-middle lamellae [CCML]) by the three types of cellulose particles was investigated by nanoindentation. Results showed that cellulose nano-materials can improve the mechanical properties of both adhesives and the cell wall structure. CNF-C had the most obvious reinforcing effect on the elastic modulus (Er) and hardness within the glue line. With modification, the Er and hardness reached 13.0 and 0.436 GPa, respectively, in the S2 layer far from the glue line. In comparison, the control sample had an Er and hardness of 7.31 and 0.256 GPa, respectively.
  • Researchpp 5542-5556Jayamani, E., Hamdan, S., Rahman, M. R., Heng, S. K., and Bin Bakri, M. K. (2014). "Processing and characterization of epoxy/luffa composites: Investigation and chemical treatment of fibers on mechanical and acoustical properties," BioRes. 9(3), 5542-5556.AbstractPDF
    This study focuses on the development of epoxy/luffa composites and the investigation of their mechanical and acoustical properties. The fibers underwent an alkalization treatment, and its effects on the mechanical and sound absorption properties of the composites were measured utilizing a universal testing machine and two-microphone transfer function impedance tube methods. The effects of chemical modifications on the fibers were studied using a scanning electron microscope (SEM). The thermal analyses of composites were conducted using thermo-gravimetric analysis (TGA). The composite’s functional group was identified and evaluated using Fourier transform infrared spectroscopy (FTIR). The sound absorption coefficient of untreated and treated composites across a range of frequencies was very similar. Untreated composites appeared to perform better than those that were treated. Compared with untreated fiber composites, there was an improvement in the tensile strength of the treated fiber composites. The SEM characterization showed that the alkaline treatment changed the morphology of the fibers, resulting in a decrease in the sound absorption coefficients of the composites. The thermal characterization of composites showed that dehydration and degradation of lignin occurred in a temperature range of 40 to 260 °C, and the maximum percentage of cellulose was found to decompose at 380 °C.
  • Researchpp 5557-5566Mu, C., Xue, L., Zhu, J., Jiang, M., and Zhou, Z. (2014). "Mechanical and thermal properties of toughened poly(L-lactic) acid and lignin blends," BioRes. 9(3), 5557-5566.AbstractPDF
    Fully degradable poly(L-lactic) acid (PLLA) and lignin blends were prepared using the melt blending method. The impact strength of PLLA was dramatically improved by 52.4% and 36.6% with the addition of 5 wt% and 10 wt% of lignin, respectively. Meanwhile, the Young’s modulus was maintained. Polarized optical microscopy (POM) results indicated that lignin served as a nucleating agent for the heterogeneous crystallization of PLLA in blends, which was responsible for the improvement in the impact strength. The introduced lignin also promoted the cold-crystallization of PLLA, which was demonstrated by differential scanning calorimetry (DSC). The blends of PLLA with lignin are considered to be a promising material because of the improved toughness, the full degradability, and the lower price compared with pure PLLA.
  • Researchpp 5567-5576Guan, M., Wang, L., and Yong, C. (2014). "Digital image correlation measuring shear strain distribution on wood/adhesive interphase modified by sealants," BioRes. 9(3), 5567-5576.AbstractPDF
    In this study, three different sealants (gelatinized starch (GS), gelatinized starch/wood flour mixture (GSWF), and soy-protein adhesive (SPA)) were used to seal the lathe checks in veneers before applying phenol formaldehyde adhesive. The shear strain distribution on the interphase of the lap joint specimens was measured by a digital image correlation technique. The results showed that the average shear strain along the bond line on the interphase was 1.94×10-3 when the specimen had lathe checks. Sealing treatment can thus reduce the average shear strain effectively. Soy-protein adhesive seemed to have the greatest ability to decrease the average shear strain along the bond line, from 1.94×10-3 to 0.94×10-3. In contrast, gelatinized starch appeared to decrease the strain slightly to 1.61×10-3. Average shear strain along the bond line of specimens treated with gelatinized starch/wood flour mixture was 1.00×10-3, which was between the values of the other two sealants. Dry shear strength of samples treated by GS and SPA increased from 7.6 MPa to 9.65 MPa and 8.85 MPa, respectively. The mixture of GSWF decreased the strength to 6.32 MPa. Wet strength of treated samples were smaller than untreated ones.
  • Researchpp 5577-5587Ćilerdžić, J., Stajić, M., Vukojević, J., and Lončar, N. (2014). "Intraspecific diversity in the production and characterization of laccase within Ganoderma lucidum," BioRes. 9(3), 5577-5587.AbstractPDF
    Ganoderma lucidum has a well-developed ligninolytic enzyme system, where laccase is the dominant and sometimes only synthesizing enzyme, and therefore could find an application in the delignification of abundant plant raw materials and in food, feed, paper, and biofuel production. The questions that provided the goals for the present study were whether the profile of G. lucidum laccase depends on cultivation type and carbon source, as well as whether intraspecific diversity exists. Conditions of submerged cultivation proved more preferable for laccase activity compared with solid-state cultivations in all studied strains, while oak sawdust provided a better carbon source than wheat straw. Maximum laccase activity (7241.0 U/L) was measured on day 14 of oak sawdust submerged fermentation by strain BEOFB 431. Intraspecific diversity in synthesized proteins was more significant in wheat straw than in oak sawdust submerged fermentation. The profile of laccase isoforms was dependent on strain, plant residue, type, and period of cultivation. Four acidic laccase isoforms (pI 3.6) were detected in G. lucidum BEOFB 431 at the same cultivation point where maximal enzyme activity was measured.
  • Researchpp 5588-5603Pánek, M., Reinprecht, L., and Hulla, M. (2014). "Ten essential oils for beech wood protection - Efficacy against wood-destroying fungi and moulds, and effect on wood discoloration," BioRes. 9(3), 5588-5603.AbstractPDF
    This work analyses the anti-fungal efficacy and stability of 10 essential oils, as well as their colour stability, in wood. The efficacy of oils against the decay fungi Coniophora puteana and Trametes versicolor as well as the moulds Aspergillus niger and Penicillium brevicompactum was evaluated first on filter papers treated with 1, 3.5, 10%, or 100% concentrate, and then on beech wood treated with 10% solutions. Accelerated ageing of treated beech samples was done before mycological tests and consisted of heating, leaching followed by heating, and Xenotest followed by heating. The highest growth inhibition of moulds and C. puteana was caused by thyme, oregano, sweet flag, and clove oils, while the savory and birch oils were less effective. These oils are potentially useful for wood protection against brown-rot fungi and moulds, mostly in interior conditions. The essential oils had only a negligible effect against the white-rot fungus T. versicolor, which was more apparent after previous ageing of wood. Some essential oils with a yellow tone (birch, oregano, sweet flag, savory, and tea tree oils) significantly changed (p<0.05) the natural colour of beech wood, but the new colours were relatively stable and underwent only mild changes after accelerated ageing in Xenotest.
  • Researchpp 5604-5614Nie, S., Yao, S., Qin, C., Li, K., Liu, X., Wang, L., Song, X., and Wang, S. (2014). "Kinetics of AOX formation in chlorine dioxide bleaching of bagasse pulp," BioRes. 9(3), 5604-5614.AbstractPDF
    In this paper, a kinetic model of the first chlorine dioxide bleaching stage (D0) in an elemental chlorine-free (ECF) bleaching sequence is presented for bagasse pulps. The model is based on the rate of adsorbable organic halogen (AOX) formation. The effects of the chlorine dioxide dosage, the sulfuric acid dosage, and the reaction temperature on the AOX content of wastewater are examined. The reaction of AOX formation could be divided into two periods. A large amount of AOX was formed rapidly within the first 10 min. Ten minutes later, the AOX formation rate significantly decreased. The kinetics could be expressed as: , where W is the AOX content, t is the bleaching time (min), T is the temperature (K), is the dosage of chlorine dioxide (kg/odt), and is the dosage of sulfuric acid (kg/odt). The fit of the experiment results obtained for different temperatures, initial chlorine dioxide dosages, initial sulfuric acid dosages, and AOX content were very good, revealing the ability of the model to predict typical mill operating conditions.
  • Researchpp 5615-5626Yu, H., Yang, X., Jiang, L., and Chen, D. (2014). "Experimental study on co-gasification characteristics of biomass and plastic wastes," BioRes. 9(3), 5615-5626.AbstractPDF
    Co-gasification of biomass (rice straw) and polyethylene (PE) was conducted in a lab-scale entrained-flow gasifier. The influences of PE proportion, reaction temperature, and equivalence ratio on producer gas composition, gasification index, and tar yield were investigated. In addition, the effects of dolomite and ) catalysts on the co-gasification process were also examined. Increased PE proportion led to an increased lower heating value (LHV) of producer gas as well as an increase in tar yield. In addition, a higher reaction temperature could improve both gas quality and gasification indices significantly. An equivalence ratio (ER) of 0.25 led to a relatively high LHV and low tar yield. Na2CO3 showed a better tar removal efficiency than dolomite. Dolomite increased the LHV of producer gas, while Na2CO3 decreased the LHV. The difference in the catalyst proportion did not cause any significant change in the gas composition and gasification indices. The producer gas with the highest LHV and lowest tar yield was obtained by the co-gasification of 80% (w/w) straw, 20% (w/w) PE, and 3% (w/w) dolomite.
  • Researchpp 5627-5635Akudo, C. O., and Theegala, C. S. (2014). "Quantification of tars, particulates, and higher heating values in gases produced from a biomass gasifier," BioRes. 9(3), 5627-5635.AbstractPDF
    Syngas from biomass gasifiers contains impurities such as tars and particulates, which can create difficulties for the downstream processes (e.g., internal combustion engines and the Fischer-Tropsch process). To design an efficient and effective gas cleaning system, it is important to accurately quantify the tars and particulates. The absence of an ASTM procedure for tars and particulates produced from a gasifier led to the development and testing of the protocol presented in this study. Syngas was generated from woodchips using a pilot-scale downdraft gasifier, which was designed and constructed in-house. The sampled impurities were analyzed using mass gravimetry, solvent evaporation, and weight differential methods. The higher heating value of the exiting gases was estimated from the syngas composition. The average tar and particulate concentrations of the sample runs were 1.8 to 3.1 g/m3 and 5.2 to 6.4 g/m3, respectively. The higher heating values of the syngas ranged between 4.38 and 4.55 MJ/m3.
  • Researchpp 5636-5651Husseinsyah, S., Chan, M. Y., Kassim, A. R., Mosthapa Zakaria, M., and Ismail, H. (2014). "Kapok husk-reinforced soy protein isolate biofilms: Tensile properties and enzymatic hydrolysis," BioRes. 9(3), 5636-5651.AbstractPDF
    The utilization of kapok husk (KH) as a reinforcing filler can enhance the properties of soy protein isolate (SPI)/kapok husk (KH) films. The properties of soy protein isolate/kapok husk films with and without the cross-linking agent glutaraldehyde (GLA) were investigated. Films with different KH contents were prepared through a solvent casting method. The addition of KH to SPI films increased the tensile strength, modulus of elasticity, and thermal stability, but reduced the elongation at break. The presence of glutaraldehyde improved the tensile and thermal properties of SPI/KH films. The tensile strength of modified SPI/KH films at 40 wt% increased by 30% compared to unmodified films. The improvement of interfacial interaction between the KH and SPI was demonstrated using a morphology study. Fourier transmission infrared spectroscopy (FTIR) analysis indicated the presence of ethylenic (C=C) groups and imine (C=N) groups. An enzymatic degradation test of SPI/KH films was performed for 14 days in a diatase buffer solution at 37 °C. The enzymatic degradation weight loss of unmodified films decreased with increasing KH content. In contrast, the modified SPI/KH films with glutaraldehyde retained about 50% of their original weight.
  • Researchpp 5652-5661Li, Z., Fei, B., and Jiang, Z. (2014). "Comparision of dilute organic and sulfuric acid pretreatment for enzymatic hydrolysis of bamboo," BioRes. 9(3), 5652-5661.AbstractPDF
    Pretreating bamboo is essential to overcome the recalcitrance of lignocellulose for bioethanol production. In this study, the effectiveness of formic, acetic, and sulfuric acids in pretreating bamboo were compared. To measure pretreatment efficiency, the enzymatic digestibility of the pretreated bamboo substrates was determined. Monomeric glucose conversion yield was measured after enzymatic hydrolysis. Additionally, the sugar degradation products fermentation inhibitors were measured after pretreatment. After conducting many tests, it was determined that pretreatment with dilute formic acid at 180 °C and 30 min can be an acceptable alternative to dilute sulfuric acid pretreatment.
  • Researchpp 5662-5675Yuan, Q., and Fu, F. (2014). "Application of carbon fiber paper in integrated wooden electric heating composite," BioRes. 9(3), 5662-5675.AbstractPDF
    To endow wooden material with an electric heating function, carbon fiber paper, as an electric heating membrane, was laminated with wood veneer to prepare wooden electric heating composites. The electric heating performance of the membrane under different power densities and resistance stabilities, as well as the influencing mechanism of the process on both the resistance and bonding performance of the composite, were studied. The surface temperature of the membrane and composite increased by more than 20 °C in 30 s and 10 min, respectively, after electricity was applied. Furthermore, the samples had a surface temperature unevenness of 4 and 2 °C, respectively. Many potential contact points between carbon fibers fulfilled their connections, reducing the drop rate of resistance (DRR) after hot-pressing to the range of 30% to 43%. The hot-press pressure and glue spread had a high degree of relevancy (coefficient of determination R2=0.960 and R2=0.997) with the DRR of the composite, respectively. The composite exhibited a negative temperature coefficient effect (NTC), and the DRR after heating for 15 h was 4.4%, but tended to ultimately stabilize. The composite, which exhibited good time-temperature effects and had a linear relationship with a high value of the coefficient of determination (R2=0.983) between power density and equilibrium temperature, displays solid potential for use in preparing integrated wooden electric heating products.
  • Researchpp 5676-5687Gaff, M., (2014). "Three-dimensional pneumatic molding of veneers," BioRes. 9(3), 5676-5687.AbstractPDF
    The goal of this paper is to introduce a new testing method suitable for the evaluation of the three-dimensional (3-D) moldability of veneers and to use this method to test the impact of specific factors on the 3-D pneumatic molding process. The tested factors included veneer moisture content, wood species, shape of test piece, and fixing method on the maximum wood deflection. Veneers were molded using compressed air on equipment designed by our group for the sole purpose of this experiment. The results indicated that the monitored factors had an effect on deflection during the 3-D molding process. The results of this investigation extend the state-of-the-art knowledge regarding this technology and indicate the possibility of utilizing this innovative testing method for 3-D molded veneers.
  • Reviewpp 5688-5706Namvar, F., Jawaid, M., Md Tahir, P., Mohamad, R., Azizi, S., Khodavandi, A., Rahman, H. S., and Nayeri, M. D. (2014). "Potential use of plant fibres and their composites for biomedical applications," BioRes. 9(3), 5688-5706.AbstractPDF
    Plant-based fibers such as flax, jute, sisal, hemp, and kenaf have been frequently used in the manufacturing of biocomposites. Natural fibres possess a high strength to weight ratio, non-corrosive nature, high fracture toughness, renewability, and sustainability, which give them unique advantages over other materials. The development of biocomposites by reinforcing natural fibres has attracted attention of scientists and researchers due to environmental benefits and improved mechanical performance. Manufacturing of biocomposites from renewable sources is a challenging task, involving metals, polymers, and ceramics. Biocomposites are already utilized in biomedical applications such as drug/gene delivery, tissue engineering, orthopedics, and cosmetic orthodontics. The first essential requirement of materials to be used as biomaterial is its acceptability by the human body. A biomaterial should obtain some important common properties in order to be applied in the human body either for use alone or in combination. Biocomposites have potential to replace or serve as a framework allowing the regeneration of traumatized or degenerated tissues or organs, thus improving the patients’ quality of life. This review paper addresses the utilization of plant fibres and its composites in biomedical applications and considers potential future research directed at environment-friendly biodegradable composites for biomedical applications.
  • Reviewpp 5707-5737Akinbomi, J., Brandberg, T., Sanni, S. A., and Taherzadeh, M. J. (2014). "Development and dissemination strategies for accelerating biogas production in Nigeria," BioRes. 9(3), 5707-5737.AbstractPDF
    Following the worsening energy crisis of unreliable electricity and unaffordable petroleum products coupled with the increase number of poverty-stricken people in Nigeria, the populace is desperately in need of cheap alternative energy supplies that will replace or complement the existing energy sources. Previous efforts by the government in tackling the challenge by citizenship sensitization of the need for introduction of biofuel into the country’s energy mix have not yielded the expected results because of a lack of sustained government effort. In light of the shortcomings, this study assesses the current potential of available biomass feedstock for biogas production in Nigeria, and further proposes appropriate biogas plants, depending on feedstock type and quantity, for the six geopolitical zones in Nigeria. Besides, the study proposes government-driven biogas development systems that could be effectively used to harness, using biogas technology, the estimated 270 TWh of potential electrical energy from 181 million tonnes of available biomass, in the advancement of electricity generation and consequent improvement of welfare in Nigeria.
  • Reviewpp 5738-5773Knob, A., Fortkamp, D., Prolo, T., Izidoro, S. C., and Almeida, J. M. (2014). "Agro-residues as alternative for xylanase production by filamentous fungi," BioRes. 9(3), 5738-5773.AbstractPDF
    Agro-industrial wastes are the most abundant renewable resource on earth and are available in large quantities. However, the disposal of these wastes presents an increasing environmental problem. Recently, there has been a great interest in the exploitation of these wastes as low-cost raw materials for the production of value-added compounds as microbial enzymes by submerged or solid-state fermentation systems. This review focuses on alternatives for xylanase production using agro-residues as substrates. In recent years, the interest in xylanase, which plays an important role in the breakdown of xylan, has markedly increased due to its wide variety of biotechnological applications. Among several agro-industrial residues that have been intensively investigated, many, such as wheat bran, wheat straw, and sugarcane bagasse, are suitable and result in high yields of xylanase, leading to low production costs. In addition, many relatively unexplored residues, such as oil palm wastes, sorghum straw, and coffee by-products, are some of the most promising substrates for xylanase production, requiring further assessment.