NC State
  • Editorialpp 1-2McKeand, S. (2015)."The success of tree breeding in the southern US," BioRes. 10(1), 1-2.AbstractArticlePDF

    Nowhere in the world have tree improvement and silviculture had a bigger impact on forest productivity and value to landowners than in the southern US. The economic impact from almost 60 years of tree improvement in the southern United States has been staggering. For example, over 300,000 hectares are planted each year with seedlings from the breeding efforts with loblolly pine (Pinus taeda) by members and staff of the North Carolina State University Cooperative Tree Improvement Program. The present value of continued genetic gains from traditional tree improvement efforts is estimated to be $2.5 billion USD to landowners and citizens in the southern US.

  • Editorialpp 3-5Chi, C., Liu, M., Gong, Y., Zhang, S., and Zhang, B. (2015). "Fractal-based research approach for lignocellulose-to-ethanol conversion," BioRes. 10(1), 3-5.AbstractArticlePDF

    The microstructure of porous lignocellulose has irregularity, which represents self-similarity within the scope of a certain scale, and the conversion process of lignocellulose to bioethanol is complex. The fractal theory appears to be well suited to be an effective tool for describing and studying such irregularity and complexity. Why not introduce the fractal theory as a potentially efficient and effective way to describe the process? Here in this paper, the research development of fractal theory and its potential application in lignocellulose microstructure and enzymatic hydrolysis kinetics are discussed.

  • Editorialpp 6-9Hubbe, M. A. (2015). "What next for wood construction/demolition debris?" BioRes. 10(1), 6-9.AbstractArticlePDF

    Residents in localities throughout the world voluntarily participate in the routine recycling of household wastes, such as paper, metals, and plastics containers. But when a house in their neighborhood gets built or torn down, most of the debris – including wood waste – gets landfilled. Such a waste of material suggests that there are opportunities to add value to these under-utilized resources. The great variability, as well as contamination, pose major challenges. It is recommended that reclaimed wood be primarily used in the manufacture of durable goods, and then whatever is left over be used for energy (or heat) generation.

  • Editorialpp 10-13Gao, Y., Shen, J., and Li, Q. (2015). "China's high-yield pulp sector and its carbon dioxide emission: Considering the saved standing wood as an increase of carbon storage," BioRes. 10(1), 10-13.AbstractArticlePDF

    The production of high-yield pulp in China has increased significantly in recent years. The well-known advantages of this type of pulp include low production cost, high opacity, and good paper formation. In the context of state-of-the-art technologies, China’s high-yield pulping, which is dominated by the PRC-APMP (preconditioning refiner chemical treatment-alkaline peroxide mechanical pulping) process, has a much higher energy input but a significantly lower wood consumption in comparison with the kraft pulping process. If the saved wood in the forest or plantation is considered as an increment of carbon storage, then the carbon dioxide emission from the production of high-yield pulp can be regarded as much lower than that of kraft pulp.

  • Researchpp 14-29Md Yunos, N. S. H., Samsu Baharuddin, A., Md Yunos, K. F., Hafid, H. S., Busu, Z., Mokhtar, M. N., Sulaiman, A., and Md. Som, A. (2015). "The physicochemical characteristics of residual oil and fibers from oil palm empty fruit bunches," BioRes. 10(1), 14-29.AbstractArticlePDF

    Abundant oil palm empty fruit bunches (OPEFB) generated from the palm oil mill industry create huge problems for the environment and the palm oil mill itself. Despite the importance of determining the amount of oil left in the OPEFB, little research of that nature has been reported. This study describes the oil content and physicochemical characteristics of OPEFB fibers, detection of oil attachment on the fiber’s surface using sudan red dye, contact angle values, and also the quality of the residual oil. The OPEFB fibers, which are normally used as mulch for the palm oil mill, have been found to be a rich source of lignocellulosic materials, especially cellulose, which constitutes 33.70 to 35.10% for a press-shredded fiber. Residual oil (3 to 7% on dry basis) extracted from the OPEFB exhibits good quality parameters such as deterioration of bleachability index (DOBI), free fatty acid (FFA), and peroxide value (PV). The DOBI values were still in the acceptable range, which is from 1.94 to 2.43, while the PV results are within the range of about 1.84 to 2.80 meq/kg. The major fatty acids of the residual fiber oil were palmitic and oleic acids, at 39.77% to 39.89% and 39.55% to 42.60%, respectively. There were no significant changes in the macronutrients and quality of the OPEFB residual oil. Therefore, the residual oil from the OPEFB should be recovered and reused as a raw material for industrial applications, boosting the oil extraction rate (OER) in the palm oil industry.

  • Researchpp 30-40Yu, Q., Xu, C., Zhuang, X., Yuan, Z., He, M., and Zhou, G. (2015). "Xylo-oligosaccharides and ethanol production from liquid hot water hydrolysate of sugarcane bagasse," BioRes. 10(1), 30-40.AbstractArticlePDF

    With the objective of maximizing the use of liquid hot water hydrolysate of sugarcane bagasse, xylo-oligosaccharides and ethanol were respectively produced by the methods of purification and microbial fermentation. The processes of purification with activated charcoal, overliming, solvent extraction, vacuum evaporation, and use of an ion exchange resin were evaluated, and the results indicated that anion exchange chromatography performed well in terms of by-product removal. The recovery and purity of xylo-oligosaccharides reached 92.0% and 90.4%, respectively, using column chromatography with the resin LS30 at a flow rate of 2 mL/min at 25 °C. The hydrolysate was used in ethanol fermentation with Pichia stipitis CBS6054 followed by the production of fermentable saccharides and detoxification. The highest ethanol concentration was 4.12 g/L with a theoretical yield of 47.9% for the hydrolysate after xylanase digestion and resin detoxification, similar to the data of the control experiment, which had an ethanol concentration of 4.64 g/L and a yield of 49.6%. However, the former had a higher ethanol productivity of 0.0860 g/(L∙h), and the highest ethanol concentration appeared 12 to 24 h earlier compared to the control. This study suggests that combined generation of xylo-oligosaccharides and cellulosic ethanol could help maximize profits for a cane sugar factory.

  • Researchpp 41-54Chen, M., Chen, Y., Zhou, X., Lu, B., He, M., Sun, S., and Ling, X. (2015). "Improving water resistance of soy-protein wood adhesive by using hydrophilic additives," BioRes. 10(1), 41-54.AbstractArticlePDF

    Soy protein adhesives are good candidates for the replacement of formaldehyde-based adhesives due to environmental concerns. However, poor water resistance has limited their application. This study was conducted to improve the water resistance of a soy-protein adhesive intended for plywood by polyethylene glycol (PEG) with different molecular weights. Ethylene glycol (EG), diethylene glycol (DEG), 400-, 2000-, and 10000-dalton polyethylene glycols were used as additives to soy protein isolate (SPI). The hydrogen bonding interaction, thermal properties, wettabilities on poplar veneer, and adhesion properties of the blended adhesives were investigated. Results showed that improving the wettability and intermolecular hydrogen bonding, induced by ethylene glycol, increased the wet adhesion strength by 30%. Higher-molecular weight polyethylene glycol imposed a decrease in adhesion due to its poor water resistance. Based on the present results, it is proposed to improve the water resistance of soy adhesives by introducing hydrophilic polyols, which also could simultaneously improve surface wetting and wet adhesion.

  • Researchpp 55-67López, F., García, M. T., Mena, V., Loaiza, J. M., Zamudio, M. A. M., and García, J. C. (2015). "Can acceptable pulp be obtained from Eucalyptus globulus wood chips after hemicellulose extraction?" BioRes. 10(1), 55-67.AbstractArticlePDF

    This study investigates the operating conditions used in the soda-anthraquinone pulping of Eucalyptus globulus wood after autohydrolysis pretreatment on the yield, kappa number, and brightness of the resulting unbleached pulp. Moreover, strength-related properties of the resulting handsheets was examined to identify the best pulping conditions and compare the outcome with that of a conventional soda-anthraquinone pulping process. The paper strength properties of the pulp were similar to or better than papers made from soda-AQ delignified pulps conducted in a single step. Also, a liquid fraction with a substantial content in hemicellulosic extracts was recovered in the simplified process. Autohydrolysis of the raw material facilitates carrying out soda-AQ pulping under milder conditions. In addition, autohydrolysis improves other properties relative to paper from raw cellulose pulp. Yield, kappa number, and brightness for pulp from solid residues of autohydrolysed eucalyptus wood were similar to those for pulp from untreated eucalyptus wood.

  • Researchpp 68-78Zhang, X., Cheng, Q., Sun, L., Xu, M., and Via, B. (2015). "The effect of layer moisture content distribution on lumber surface and bonding interface properties," BioRes. 10(1), 68-78.AbstractArticlePDF

    This study investigated the effect of drying on moisture content (MC) distribution through ash lumber thickness, as well as the effect on wood surface and bonding at the interface. After the drying of lumber, the wood surface contact angles and free energy were collected over 6 days, and the MC difference (between surface and core) was measured. At the same time, the isocyanate adhesive strength, as well as the elemental composition of carbon (C1s), nitrogen (N1s), and oxygen (O1s) on the lumber surface and at the bonding interface, were tested daily. Both the wood surface contact angle and free energy changed with a change in MC difference. The O1s concentration at the bond interface decreased with increased MC difference, and the adhesive strength declined accordingly. To attain the best bond interface, the MC difference between the surface and core should be controlled within the range of 0.5 to 1%.

  • Researchpp 79-87Peker, H., Tan, H., and Ersen, N. (2015). "Effects of steaming, drying temperature, and adhesive type on static bending properties of LVL made of Picea orientalis and Abies nordmanniana veneers," BioRes. 10(1), 79-87.AbstractArticlePDF

    The modulus of elasticity (MOE) and modulus of rupture (MOR) were evaluated for laminated veneer lumber (LVL) in static bending. The studied species were spruce (Picea orientalis) and fir (Abies nordmanniana) originated from the Eastern Black sea region and prepared with phenol-formaldehyde and melamine-urea-formaldehyde. The effect of wood species, steaming, drying temperature, and type of adhesive on static bending MOE and MOR were determined. According to the experimental results, the bending strength of spruce wood (Maçka) treated with phenol formadehyde adhesives is the highest for the specimens steamed for 6 h at a drying temperature of 110 ºC. Furthermore, the modulus of elasticity for spruce wood (Maçka) treated with phenol formadehyde adhesive is the highest for the specimens steamed for 12 h and subjected to a drying temperature of 150 ºC.

  • Researchpp 88-104Cui, L., Yan, J., Li, L., Quan, G., Ding, C., Chen, T., Yin, C., Gao, J., and Hussain, Q. (2015). "Does biochar alter the speciation of Cd and Pb in aqueous solution?" BioRes. 10(1), 88-104.AbstractArticlePDF

    Cadmium and lead contamination in bodies of water has been a serious concern because of risk to the environment. A laboratory experiment was initiated to investigate the efficacy of biochar (BC) in removing cadmium and lead (Cd and Pb, respectively) from solution. After absorption by BC, the fractions of Cd and Pb at different solution temperatures were measured. The adsorption data were described by Langmuir isotherm with maximum adsorption capacities of 6.36, 6.47, and 6.74 mg Cd g-1 and 50.05, 55.86, and 63.09 mg Pb g-1 at 25, 35, and 45 °C, respectively. The adsorption capacities were affected by Cd/Pb initial concentration, pH, BC particle size, BC dosage, and reaction time. Biochar adsorbed the Cd and Pb mainly as species bound with carbonate (> 50%) and organic compounds (~40%). Exchangeable and residual fractions of Cd and Pb were less than 10%. Results from this study indicate that BC is highly effective in the adsorption of the heavy metals Cd and Pb through binding with carbonates.

  • Researchpp 105-122Shahid, S. A., Ali, M., and Zafar, Z. I. (2015). "Cure kinetics, bonding performance, thermal degradation, and biocidal studies of phenol-formaldehyde resins modified with crude bio-oil prepared from Ziziphus mauritiana endocarps," BioRes. 10(1), 105-122.AbstractArticlePDF

    Crude bio-oil, extracted from endocarp bio-waste of Ziziphus mauritiana by direct liquefaction (ethanol-water 1:1 w/w; 300 °C), was used to replace petro-phenol (30% to 75% w/w) in the development of bio-oil-phenol formaldehyde (BPF) resol resins. Cure kinetics of the BPF resins were studied by the DSC method, while the thermal degradation was studied by the TGA method. Bonding performance of the BPF resins was measured by single lap-shear method, while biocidal properties were investigated by antifungal index (%) and termite mortality (%) test. The DSC studies revealed that beyond 45% bio-oil incorporation (BOI), the curing process of the BPF resins got deferred. The TGA studies showed that BOI decreased the thermal stability of the BPF resins by lowering the decomposition temperatures and the char residue. The measured values of antifungal index (%) and termite mortality (%) revealed that incorporation of bio-oil enhanced the fungal and termite resistance of the resins. From data of thermal cure, bonding strength, thermal stability, and biocidal properties of the BPF resins it appears that petro-phenol could be substituted by up to 45% w/w of crude bio-oil safely in the development of bio-oil-phenol formaldehyde resol resins.

  • Researchpp 123-136Then, Y. Y., Ibrahim, N. A., Zainuddin, N., Ariffin, H., Wan Yunus, W. M. Z., and Chieng, B. W. (2015). "Static mechanical, interfacial, and water absorption behaviors of alkali treated oil palm mesocarp fiber reinforced poly(butylene succinate) biocomposites," BioRes. 10(1), 123-136.AbstractArticlePDF

    In this work, oil palm mesocarp fiber (OPMF) was surface-treated with varying NaOH concentrations (1, 3, 5, 7, or 9%) and soaking times (1, 2, 3, or 4 h) at room temperature aiming to enhance its adhesion to the thermoplastic matrix for biocomposite application. The biocomposites from alkali treated OPMFs and poly(butylene succinate) at weight ratios of 70:30 were fabricated by a melt blending technique and hot-pressed moulding. The results indicate that NaOH treatment removed fiber’s surface waxes, hemicellulose, and lignin, and produced fiber with rough surface morphology. The tensile results showed that OPMF treated in 5% NaOH solution for 3 h produced biocomposite with enhanced tensile strength (30%), tensile modulus (105%), and elongation at break (16%), as well as reduced water absorption (15%) and thickness swelling (13%) in comparison to that of untreated OPMF. Scanning electron microscopy showed improvement of interfacial adhesion between treated fiber and poly(butylene succinate). These results suggest that NaOH treatment could be an effective form of treatment for OPMF in biocomposites materials.

  • Researchpp 137-144Song, X., Bie, R., Ji, X., Chen, P., Zhang, Y., and Fan, J. (2015). "Kinetics of reed black liquor (RBL) pyrolysis from thermogravimetric data," BioRes. 10(1), 137-144.AbstractArticlePDF

    The pyrolysis of reed black liquor (RBL) was studied in nitrogen atmosphere by thermogravimetric analysis at six different heating rates of 5, 10, 20, 30, 40, and 50 ˚C·min-1 from ambient temperature (25 ˚C) to 800 ˚C. Thermogravimetric (TG) and differential thermogravimetric (DTG) curves were obtained. The results show that there are three main weight-loss stages in the temperature ranges of 180 to 350, 350 to 560, and 560 to 800 ˚C, for which the error is about ± 10 ˚C. The kinetic parameters were determined by the Coats-Redfern method. A kinetic compensation effect (KCE) between activation energy (E) and pre-exponential (A) factor also was found.

  • Researchpp 145-154Hu, Z., Liu, B., Lin, J., Hu, G., Wang, L., and Zhang, X. (2015). "Interfacial modification and dispersion of short carbon fiber and the properties of composite papers as gas diffusion layer for proton exchange membrane fuel cell (PEMFC)," BioRes. 10(1), 145-154.AbstractArticlePDF

    Short carbon fibers (SCF) were modified with oxidation and coupling treatment to improve their water-wettability and bonding properties. Four types of dispersants were studied and discussed. Short carbon fibers/plant fiber (PF) composite papers were prepared by papermaking techniques. Scanning electron microscopy (SEM) and tests to determine zeta potential, absorbance, tensile index, and conductivity were carried out to investigate the modified effect of SCF and the interfacial properties. Modification experimental results showed that the surface grooves were deepened and new superficial grooves were generated by the liquid acid oxidation. The reaction with the silane coupling agent provided higher density and more uniform distribution on the SCF surface than that of organic titanate, and it obviously increased the roughness and the absolute value of zeta potential. After modification, the hydrophilic properties and dispersion in aqueous solutions were improved, the SCFs could form a good mechanical grip with plant fibers, and the conductivity and physical strength of SCF/PF composite papers were enhanced. It was shown that there was obvious adhesive binding at the fiber overlap nodes by the SEM analysis. It was confirmed that the improvement of physical properties of composite paper can be ascribed to the interfacial enhancement.

  • Researchpp 155-168Liu, M., Chen, Y., Chen, K., Zhang, N., Zhao, X., Zhao, F., Dou, Z., He, X., and Wang, L. (2015). "Biomass-derived activated carbon for rechargeable lithium-sulfur batteries," BioRes. 10(1), 155-168.AbstractArticlePDF

    High-surface-area activated carbon (HSAAC) was synthesized by carbonizing coconut shells and subsequently activating the material with KOH. The as-prepared HSAAC had a mostly microporous structure (with small mesoporous inclusions) and exhibited a high specific surface area of 2258.7 m2g-1 and an average pore size of 2.246 nm. Sulfur was then loaded into the activated carbon (AC), and this S/HSAAC (62 wt%) was used as a cathode for Li-S batteries. These batteries delivered an initial discharge capacity of 1233 mAhg-1 at a current density of 200 mAg-1. Due to the strong absorption force of the micropores and a high pore volume, the cells retained 929 mAhg-1 with 80% capacity retention of the initial discharge after 100 cycles. Considering its low cost and ability to be produced at a large-scale, biomass-derived HSAAC is a promising electrode material that may advance high-energy rechargeable lithium-sulfur batteries toward use in practical applications.

  • Researchpp 169-181Nazerian, M., Dalirzadeh, A., and Farrokhpayam, S. R. (2015). "Use of almond shell powder in modification of the physical and mechanical properties of medium density fiberboard," BioRes. 10(1), 169-181.AbstractArticlePDF

    This study evaluated the effects of almond shell powder content as an extender, as well as the effects of varying paraffin contents, temperature, and press time on the properties of medium-density fiberboard. Response surface methodology (RSM) based on a five-level, four-variable central composite rotatable design was applied to evaluate the effects of independent variables on the modulus of rupture (MOR), internal bonding (IB), and thickness swelling (TS) of medium-density fiberboard. Mathematical model equations were derived from computer simulation programming to optimize the properties of the panels. These equations, which are second-order response functions representing MOR, IB, and TS, were expressed as functions of four operating parameters of panel properties. Predicted values were found to be in agreement with experimental values (R2 values of 0.93, 0.90, and 0.90 for MOR, IB, and TS, respectively). The study showed that RSM can be efficiently applied in modeling fiberboard properties. It was found that almond shell powder maintained the MOR, IB, and TS at desirable levels up to 10.6% as an extender in the resin. Using 1.7% paraffin as a sizing agent, a press temperature of 158 °C, and a duration of 6.43 min had the highest impact on the improvement of the studied properties of medium-density fiberboard.

  • Researchpp 182-195Yu, D., Zeng, J. S., Chen, K. F., Feng, Y. C., and Yang, X. (2015). "Rheological measurement of concentrated pulp fiber suspensions in oscillatory shear using a novel device," BioRes. 10(1), 182-195.AbstractArticlePDF

    This paper presents a novel device based on an oscillating torsion resonator with continuously varying frequency capability to characterize the rheological properties of pulp fiber suspensions in a concentrated regime. Fiber suspensions made from unbleached wheat straw pulp at concentrations ranging from 5 wt% to 15 wt% were used. Pulp suspensions exhibit shear-thinning behavior up to a limited frequency value, after which Newtonian behavior prevails. Effects of frequency, fiber concentration, and beating process on suspension viscoelastic properties are discussed. The suspensions at different concentrations are structured in a similar way, leading to a weak gel-like structure. The storage modulus (G‘) of the suspension can be determined by a two-region (shear increasing – shear decreasing) profile, while loss modulus (G”) keeps increasing for the whole frequency range investigated. At the same frequency, G‘ and G” increase nonlinearly with fiber concentration. The beating process brings a decrease in both G‘ and G”. The power-law model is used for data fitting.

  • Researchpp 196-209Chen, W. L., Liang, J. B., Jahromi, M. F., Abdullah, N., Ho, Y. W., and Tufarelli, V. (2015). "Enzyme treatment enhances release of prebiotic oligosaccharides from palm kernel expeller," BioRes. 10(1), 196-209.AbstractArticlePDF

    Heat and enzyme treatments were used to increase the prebiotic oligosaccharides from palm kernel expeller (PKE), and the prebiotic efficacy of three types of PKE-extracts, namely raw PKE-extract (PKERAW), enzyme-treated PKE-extract (PKEENZ), and steam + enzyme-treated PKE-extract (SPKEENZ) was evaluated in vitro using three strains of Lactobacillus (L. brevis I 218, L. salivarius I 24 and L. gallinarum I 16), and in vivo using Sprague-Dawley rats as an animal model. Results of the in vitro study showed that the PKE-extracts were able to support the growth of Lactobacillus sp. strains. However, their growth varied significantly among strains and PKE-extracts (P<0.05), with L. brevis I 218 recording the highest growth compared to the other two strains, and the highest growth in the steam plus enzyme (SPKEENZ) extract. Results of the in vivo study reaffirmed that all the PKE-extracts tested can support growth of beneficial bacteria (Lactobacillus and Bifidobacterium), but only SPKEENZ treatment group had significantly higher Lactobacillus and Bifidobacterium counts and lower population of E. coli compared to the control. It was demonstrated that PKE is a potential source of prebiotic, which may be used to effectively improve host health and wellbeing by modulating the host gut microflora, and by proper pre-treatment, the release of prebiotic oligosaccharides from PKE can be enhanced.

  • Researchpp 210-226Antes, R., and Joutsimo, O. P. (2015). "Effect of modified cooking on chemical composition of pulps from Eucalyptus globulus and Eucalyptus nitens," BioRes. 10(1), 210-226.AbstractArticlePDF

    The effects of SuperBatch™ (SB), CompactCooking™ (CC), and Lo-Solids™ (LS) modified cooking processes on pulp properties of Eucalyptus globulus and Eucalyptus nitens were investigated. The syringyl/guayacil (S/G) lignin ratio in the wood of E. globulus was significantly higher (4.7) than that of E. nitens (3.5). From the brown stock pulps, the viscosity, total lignin, carbohydrate composition, acetone extractives, and hexenuronic acids were measured. For the same Kappa number level (17 ± 0.5), pulps from E. globulus needed lower H-factor. They also presented a higher brightness and more cooking rejects, independent of the cooking method. CC presented a slightly higher cooking yield and pulp viscosity compared to the other modified cooking methods. At the same Kappa number level, the pulps of E. nitens presented a greater amount of total lignin, whereas E. globulus presented a higher amount of hexenuronic acid content, independent of the cooking method.

  • Researchpp 227-239Wu, G., Qu, P., Sun, E., Chang, Z., Xu, Y., and Huang, H. (2015). "Physical, chemical, and rheological properties of rice husks treated by composting process," BioRes. 10(1), 227-239.AbstractArticlePDF

    A composting treatment was employed in an effort to improve the processability of rice husks. Changes in the chemical composition, physical structure, and rheological properties of modified rice husks were analyzed. The results indicated that the average diameter of compost-treated samples was significantly higher than that of the untreated samples because they were able to adhere to each other by the bacterial protein. Scanning electron microscopy images showed that the epidermis became rugged and lumpy because the composition of rice husks (cellulose, hemicellulose, lignin, and pectin) was partially decomposed, an effect confirmed by the chemical composition and FTIR analysis. Thermogravimetric analysis showed that the composted samples had better thermal stability than the untreated ones. Stress-strain curves showed that the treated samples displayed a moderately significant change of slope at about 0 to 10% strain, and they had better mechanical properties than untreated samples. Juxtaposing the rheological properties of both untreated and treated samples determined that the latter had higher apparent viscosity as a result of degradation and bacterial protein effects. All results indicated that the composting treatment changed the physical, chemical, and rheological properties of the rice husks, which are beneficial for its utilization and processability.

  • Researchpp 240-255Huang, C., Chu, Q., Xie, Y., Li, X., Jin, Y., Min, D., and Yong, Q. (2015). "Effect of kraft pulping pretreatment on the chemical composition, enzymatic digestibility, and sugar release of moso bamboo residues," BioRes. 10(1), 240-255.AbstractArticlePDF

    In this work, kraft pulping was carried out on moso bamboo residues as a pretreatment and its impact on the chemical compositions and the digestibility of the sample was investigated. Meanwhile, steam explosion and sulfuric acid pretreatments were also carried out on the sample to determine their impacts on enzymatic saccharification. Results showed that kraft pulping pretreatment removed a significant amount of lignin from the sample, and its enzymatic saccharification was enhanced. Approximately 95% of the lignin was removed with the optimized kraft pulping pretreatment (26% effective alkali charge, 24% sulfidity, 160 °C, and 70 min cooking time). Consequently, about 79% and 77% yields of glucan and xylan, respectively, were achieved with enzymatic saccharification from the pretreated sample. As a result, 352 g, 128 g, and 88 g sugars were generated from 1000 g of samples pretreated by kraft pulping, steam explosion, and sulfuric acid, respectively. The results suggested that kraft pulping can be a remarkably effective pretreatment applied on mosobamboo residues (i.e., lignin-rich biomass) for sugars released, compared to steam explosion and sulfuric acid pretreatment.

  • Researchpp 256-271Zarina, S., and Ahmad, I. (2015). "Biodegradable composite films based on K-carrageenan reinforced by cellulose nanocrystal from kenaf fibers," BioRes. 10(1), 256-271.AbstractArticlePDF

    Through alkali treatment, bleaching, and sulfuric acid hydrolysis, cellulose nanocrystals (CNCs) were prepared from kenaf fibers and were used as reinforcement materials in biocomposites based on κ-carrageenan. Biocomposites in the form of films were prepared by solution casting of a mixture of κ-carrageenan, glycerol, and various amounts of CNCs (0 to 8 wt%). Fourier transform infrared spectroscopy (FTIR) revealed that alkali treatment followed by bleaching totally removed lignin and hemicellulose from the kenaf. Morphological analysis of the fibers, cellulose, and κ-carrageenan of biocomposite films were carried out using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The effects of filler content on the mechanical and thermal stability of the k-carrageenan biocomposite films were analyzed through tensile strength measurements and thermogravimetric analysis (TGA). At an optimum CNC content of 4%, the κ-carrageenan biocomposite films showed good dispersion, superior mechanical properties, and improved thermal stability.

  • Researchpp 272-281Miao, Y., Zhong, M., Liu, Z., and Sun, F. (2015). "Analysis of wood vibration energy attenuation based on FFT vibration signal," BioRes. 10(1), 272-281.AbstractArticlePDF

    The internal friction energy loss of vibration is an important indicator showing the vibrational performance of wood. This paper analyzed vibration signals based on the fast Fourier transform spectrum. The logarithmic average, logarithmic regression slope, and exponential function fitting methods were used to calculate the attenuation coefficient of friction energy of wood vibration in the full time and different time periods. The correlations of δ gained from different methods were compared and analyzed. The results showed that the linear correlations between different methods were significant in the entire period. The values obtained using the logarithmic average and logarithmic regression slope methods were similar. For different time periods, the rate of amplitude decay decreased over time. The values obtained using the logarithmic average method had the smallest fluctuation. In different time periods, the logarithmic average and logarithmic regression slope methods showed a significant linear correlation. However, the exponential function fitting method showed a low correlation with the logarithmic average and logarithmic regression slope methods.

  • Researchpp 282-289Xu, K., Wang, Y., Lv, J., Li, X., and Wu, Y. (2015). "The effect of microwave pretreatment on the impregnation of poplar wood," BioRes. 10(1), 282-289.AbstractArticlePDF

    Microwave pretreatment can increase the transverse permeability of wood. The effects of impregnation on microwave-pretreated wood with low-molecular weight phenol formaldehyde resin was investigated. The results showed that the improved transverse permeability of poplar wood that had received microwave pretreatment resulted in a positive influence on the effect of the impregnation. The maximum impregnation weight gain rate was 51.08%, with the average being approximately 40%. The average density of the specimens impregnated for 1.50 h at 0.8 MPa was 584.8 kg•m-3. During the course of the study, the resin present in the wood became distributed evenly in the vessel elements, wood fiber lumens, and intercellular spaces. Finally, the chromogenic reaction area accounted for 78.11% of the total area in the fluorescent staining diagram of the cross section.

  • Researchpp 290-298Gaff, M., and Gašparík, M. (2015). "Effect of cyclic loading on modulus of elasticity of aspen wood," BioRes. 10(1), 290-298.AbstractArticlePDF

    This article investigates the modulus of elasticity of solid and laminated aspen wood of various thicknesses after cyclic loading. A three-point static bending test was carried out to determine the modulus of elasticity. Cyclically loaded samples were compared with samples without cyclic loading. For the laminated wood, the results demonstrated a statistically significant impact of cyclic loading on the elasticity modulus. In contrast, no significant impact of cyclic loading was shown for the solid wood. The impact of the number of cycles was significant for both laminated and solid wood. When this number increased, the elasticity modulus values decreased. Generally, higher elasticity modulus values were confirmed for the laminated wood.

  • Researchpp 299-312AL-Oqla, F. M., Salit, M. S., Ishak, M. R., and Aziz, N. A. (2015). "A novel evaluation tool for enhancing the selection of natural fibers for polymeric composites based on fiber moisture content criterion," BioRes. 10(1), 299-312.AbstractArticlePDF

    A systematic evaluation tool for natural fibers’ capabilities based on moisture content criterion (MCC) was developed and introduced as a new evaluation method. This MCC evaluation tool is designed to predict the behavior of the available natural fibers regarding distinctive desirable characteristics under the effect of the moisture absorption phenomenon. Here, the capabilities of different natural fiber types commonly used in industry, in addition to date palm fibers, were systematically investigated based on MCC. The results demonstrated that MCC is capable of predicting the relative reduction of fiber performance regarding a particular beneficial property because of the effect of moisture absorption. The strong agreements between the predicted values of MCC and results reported in the literature verify its usefulness as an evaluation tool and demonstrate its added value steps in predicting the relative behavior of fibers with a minimal range of errors compared with experimental measurements. Therefore, MCC is capable of better evaluating natural fibers regarding distinctive criteria in a systematic manner, leading to more realistic decisions about their capabilities and therefore enhancing the selection process for both better sustainable design possibilities and industrial product development.

  • Researchpp 313-329McGavin, R. L., Bailleres, H., Hamilton, M., Blackburn, D., Vega, M., and Ozarska, B. (2015). "Variation in rotary veneer recovery from Australian plantation Eucalyptus globulus and Eucalyptus nitens," BioRes. 10(1), 313-329.AbstractArticlePDF

    The processing of Australian plantation-grown Eucalyptus globulus and E. nitens into rotary veneer was shown to produce acceptable recoveries. Three plantation sites for each species were sampled. Silvicultural treatments (thinning and pruning) and growing environments varied between sites. Graded veneer recoveries were dominated by D-grade veneer across all six sites. Variation between the E. nitens sites was evident, with recoveries differing between sites reflecting silvicultural treatments. However, only minimal variation in recovery was shown between the E. globulus sites. The presence of similar levels of defects across all E. globulus sites indicates that the intensive silvicultural management at one site studied was not effective in the production of clear wood, and may possibly have adversely affected grade recovery. Veneer value analysis demonstrated only minimal differences between E. globulus sites. More variation was observed in the E. nitens value analysis; however, intensive silvicultural management implemented did not necessarily result in higher veneer value.

  • Researchpp 330-335Barbosa, J. C., Michelon, A. L. S., De Araujo, V. A., Gava, M., Morales, E. A. M., Garcia, J. N., Lahr, F. A. R., and Christoforo, A. L. (2015). "Medium density particleboard reinforced with bamboo laminas," BioRes. 10(1), 330-335.AbstractArticlePDF

    The objective of this work was to evaluate the effect of the addition of bamboo laminas of the species Dendrocalamus giganteus to three-layer medium density particleboard (MDP). These laminas were glued onto both the top and the bottom of each panel. With the manufactured panels laminated with bamboo, mechanical tests based on the Brazilian Standard ABNT NBR 14810 were carried out to determine the modulus of rupture (MOR) in static bending and the tensile strength parallel-to-surface. These mechanical tests were realized in particleboards of eucalyptus and in reinforced particleboard, both produced in the laboratory. The modulus of rupture and tensile strength parallel-to-surface of the laminated MDP had values close to those that have been reported. The reinforcements increased the values of these studied properties. Nevertheless, this fact indicated the possibility to produce a stronger MDP using bamboo lamina as surface layers. These results show the possibility of using coated-bamboo MDP for utilization in large spans, for example, in flooring for mezzanines with finish on both sides, and for robust furniture as bookshelves, beds, tables, etc.

  • Researchpp 336-347Maalouf, C., Umurigirwa, B. S., Viens, N., Lachi, M., and Mai, T. H. (2015). "Study of the hygric behaviour and moisture buffering performance of a hemp-starch composite panel for buildings," BioRes. 10(1), 336-347.AbstractArticlePDF

    This paper presents the results of a laboratory investigation into the hygric properties and moisture buffering performance of hemp-starch composite panels designed for building applications. Composite panels were produced by bonding hemp shiv with wheat starch as a binder. Two types of hemp shiv were tested: chemically processed shiv with enhanced adhesion between fibers and starch matrix, and non-treated shiv. The panels were then characterised in terms of their hygroscopic properties (sorption curve and vapour diffusion resistance factor) and their moisture buffering performance (moisture buffering value, MBV). The determination of theoretical MBV was based on the effusivity of the material, which is obtained from its basic hygroscopic characterisation. The results show that both panels are excellent hydric regulators that can be used to improve indoor hygrothermal comfort by buffering indoor relative humidity variations.

  • Researchpp 348-368Phaodee, P., Tangjaroensirirat, N., and Sakdaronnarong, C. (2015). "Biobased polystyrene foam-like material from crosslinked cassava starch and nanocellulose from sugarcane bagasse," BioRes. 10(1), 348-368.AbstractArticlePDF

    This research aimed to study the effect of lignin, natural rubber latex (NRL), nanocellulose, and talc on production of biobased foam using cassava starch as matrix. Comparison study on lignin extraction from sugarcane bagasse (SCB) for different types of base (KOH and NaOH), concentration (10 %w/w and 40 %w/w), and temperatures (60 °C for 3 h and 120 °C for 1 h) was performed. The most suitable isolation condition giving the highest yield of lignin and lowest hemicellulose contamination was 40 %KOH at 120 oC for 1 h. A mechanical method was superior to a chemical method for cellulose size reduction owing to more appropriate size distribution and uniformity of nanocellulose. The most favorable proportion of foam contained 20% nanocellulose, 3% talc, 0.1% NRL, 38.5% water, and 76.9% crosslinked cassava starch. These conditions resulted in favorable flexural strength, modulus, and percentage of elongation, analogous to polystyrene foam. An appropriate amount of added lignin increased the elasticity of biofoam.

  • Researchpp 369-381Tang, L., Yang, X., Chen, M., Wang, X., and Zhou, X. (2015). "Surface characterization of plasma-modified poplar veneer: Dynamic wettability," BioRes. 10(1), 369-381.AbstractArticlePDF

    The dynamic wettability of plasma-modified poplar veneer was investigated with sessile adhesive droplets using a wetting model. Dynamic contact angle, instantaneous and equilibrium contact angles, and their rates of change (K-value) were used to illustrate the dynamic wetting process. The experiment consisted of selecting treatment parameters (type of gas, power) that would lead to the increased wettability of wood. Three resin systems, urea-formaldehyde (UF), phenol-formaldehyde (PF), and diphenylmethylene diisocyanate (MDI), were evaluated. Based on the wetting model, the K-value was used to interpret the kinetics of wetting. The higher the K-value, the faster the contact angle reaches equilibrium, and the faster the liquid penetrates and spreads. Therefore, the model was helpful for characterizing the dynamic wettability of wood surfaces modified with different plasma treatments. The K-values of plasma-treated veneer surfaces at different plasma power levels and with different gases (such as O2, N2, Ar, air, and NH3) were 458% to 653% and 332% to 528% higher than those of untreated veneer surfaces, respectively. In addition, the K-values of the three resins on the oxygen plasma-treated veneer surfaces were 38% to 1204% higher than those on the untreated veneer surfaces. Therefore, this method was helpful for characterizing the dynamic wettability of veneer surfaces modified with plasma treatment.

  • Researchpp 382-401Khayat, H. A., Ibrahim, N. A., Sulaiman, Y., and Yunus, W. M. Z. W. (2015). "Preparation and characterization of oil palm leaf fiber/polypropylene/epolene® E-43 composite," BioRes. 10(1), 382-401.AbstractArticlePDF

    Oil palm leaf fiber was used as a reinforcement material for the preparation of polypropylene composite. First, the influence of fiber loading on the mechanical and thermal characteristics of the composite was investigated. Epolene® E-43 was used as a compatibilizing agent to enhance the mechanical and thermal properties as well as the morphology of the oil palm leaf fiber/polypropylene composite. The composites were prepared with 10, 20, 30, 40, 50, and 60% ratios of fiber by melt blending technique using internal mixer machines and compressing molding. The addition of fiber led to an increase in the tensile and flexural properties of the composite in comparison to virgin polypropylene. Similarly, Epolene® E-43 was found to improve all the studied properties. Water absorption increased with increasing fiber loading; however, the addition of Epolene® E-43 reduced this property. According to Fourier transform infrared spectroscopy results, interactions between the components of the composite were physically indicated for all fiber content ratios, except 20% due to more interaction between the components. Dynamic mechanical analysis (DMA) showed that the presence of the oil palm leaf fiber enhances mobility but reduces stiffness. The morphological analysis of the composites using a field-emission scanning electron microscope showed that Epolene® E-43 reduced the size and number of voids, which is consistent with the results from the mechanical analysis.

  • Researchpp 402-411Gaff, M., and Gašparík, M. (2015). "Influence of cyclic stress on the relaxation speed of native and laminated wood," BioRes. 10(1), 402-411.AbstractArticlePDF

    This study examined the influence of cyclic stress on the relaxation speed for native beech wood and laminated wood. Various sample thicknesses were evaluated, and a testing method, which consisted of bending via three-point loading, was developed. The relaxation speed was measured on samples that were cyclic loaded, and the results were compared with those gathered for test samples that were not cyclically loaded. The results show that thicker materials yield a higher relaxation speed. The type of material and the number of loading cycles did not appear to have a significant effect within the measured range of values.

  • Researchpp 412-422Gaff, M., Gašparík, M., and Matlák, J. (2015). "3D molding of veneers by mechanical means," BioRes. 10(1), 412-422.AbstractArticlePDF

    The 3D moldability of veneers, as opposed to the moldability of plastic or other materials, is limited because of the characteristics of wood. By mechanical treatment under appropriate conditions, it is possible to partially modify veneer characteristics. In this study, the intention was to determine the effect of factors influencing the 3D moldability of veneers. Therefore, this study was focused on determining the 3D moldability of veneers with square and circular shape, which were stressed under six moisture content levels (i.e., 0%, 8%, 16%, 20%, 30%, and 100%). To determine the influence of wood species, the results for beech veneers of 0.5-mm thickness were compared to the results for birch veneers of 0.5-mm thickness. These sets of samples were stressed with a spherical stamping tool with three different radii of curvature (i.e., 20, 40, and 80 mm). There is currently no standardized method for assessing the 3D moldability of veneers, as opposed to metals (metal sheets). Because of the low moldability of veneers compared to metal materials, Erichsen’s method for assessing the moldability of metal sheets was modified for veneers. The 3D moldability was determined based on maximal deflection of the veneer stressed by the stamping tool before rupture. Based on the established method, the effects of wood species, moisture content of veneers, diameter of stamping tool, and shape of samples on deflection during 3D molding were determined.

  • Researchpp 423-431Wu., C., Bing, L., Yu, D., Li, R., and Zhou, S. (2015). "Preparation of dissolving pulp made from poplar residual slabs and effect of xylanase post-treatment on its reactivity," BioRes. 10(1), 423-431.AbstractArticlePDF

    The production of dissolving pulp from poplar wood residual slabs was investigated. The residual slab chips were initially prehydrolyzed and subsequently pulped by the kraft process; the resulting brownstock was bleached using a totally chlorine-free (TCF) sequence to full brightness. The pulp contained low pentosans and high α-cellulose content, and the pulp had high reactivity. Its hemicellulose content, reactivity, and degree of polymerization were within acceptable levels for a rayon-grade dissolving pulp. Thus, the residual slabs from poplar can be regarded as a viable raw material for dissolving pulp production. The reactivity of this dissolving pulp was drastically decreased after the xylanase post-treatment, which can slightly lower the pentosans levels. Simultaneously, the crystallinity index of the resulting pulp obviously decreased after xylanase post-treatment.

  • Researchpp 432-447Ren, H., Liu, Z., Zhai, H. M., Cao, Y., and Omori, S. (2015). "Effects of lignophenols on mechanical performance of biocomposites based on polyhydroxybutyrate (PHB) and polypropylene (PP) reinforced with pulp fibers," BioRes. 10(1), 432-447.AbstractArticlePDF

    The effects of lignophenols and pulp fibers as reinforcing elements in biocomposites were studied with poly-(3-hydroxybutyrate) (PHB) biopolymers and polystyrene (PS) matrix materials. Lignophenols and (NH2(CH2)3Si(OC2H5)3) were compared as plasticizing or compatibilizing additives in tests of composite properties. PHB and PP were blended with pulp fiber cellulose and lignophenol by torque rheometer, and the test specimens were processed via injection moulding. Various testing methods, including tensile and impact tests, SEM, XRD, TGA, and ART-FTIR were used to investigate the properties of the composites. PHB and PP-cellulose fiber composites with strong mechanical properties could be created by using a torque rheometer as a mixer at 190 ºC with very short mixing times. The (NH2(CH2)3Si(OC2H5)3) was found to improve the mechanical features of the PP, but not very obviously for both tensile and impact strengths of PHB. However, the lignophenols positively affected the PHB-pulp fiber composites. In summary, a novel method has been demonstrated for creating biodegradable composites with pulp fibers in the absence of a coupling agent, and lignophenols may be applicable as an additive in the cases described in this study.

  • Researchpp 448-456Hegazy, S., Ahmed, K., and Hiziroglu, S. (2015). "Oriented strand board production from water-treated date palm fronds," BioRes. 10(1), 448-456.AbstractArticlePDF

    The objective of this work was to evaluate some of the important physical and mechanical properties of experimental oriented strandboard panels manufactured from four different cultivars of date palm (Phoenix dactylifera) fronds. Currently date fronds are considered as waste and under-utilized. Open burning and landfill are common practices for such resources. Therefore experimental panels were manufactured from strands washed with water to determine the effect of such treatment on panel properties. Bending characteristics, internal bond strength, thickness swelling, water absorption, and linear expansion along and across the grain orientations of the samples were tested. Based on the findings in this work, the internal bond strength values of the samples were found to be satisfactory. However, the samples manufactured from water-soaked strands had lower mechanical and physical properties as compared to those made from unwashed material. Water treatment also adversely influenced dimensional stability, namely thickness swelling, water absorption, and linear expansion of the samples. It appears that untreated date palm fronds as underutilized resource show promise sustainable raw material for the manufacture of oriented strandboard panels, but further research is required to maximize their potential.

  • Researchpp 457-468Burawska, I., Zbieć, M., Tomusiak, A., and Beer, P. (2015). "Local reinforcement of timber with composite and lignocellulosic materials," BioRes. 10(1), 457-468.AbstractArticlePDF

    This work compares the effectiveness of local reinforcements of pine beams. Test beams were reinforced with carbon fiber reinforced polymer (CFRP) tape and layered laminate bamboo composite (LLBC) plates. The effective length of local reinforcement reached 5% of the entire beam length. Beams were tested to determine static bending strength in accordance with the EN-408 (2012) standard. On the basis of testing and calculations, it was concluded that local reinforcement with both reinforcing materials caused a significant (p < 0.05) gain in load capacity and modulus of elasticity. The LLBC, which has a tensile strength 25 times lower and a modulus of elasticity 17 times lower than CFRP, resulted in the highest load capacity. This phenomenon is related to the more uniform stress distribution on the composite with LLBC plate – glue bond – wood layers and lower strain within the bond in comparison to the CFRP reinforcement. Therefore, critical stresses within the bond were not exceeded, which often happens in reinforcement with materials of high modulus of elasticity (such as CFRP tape).

  • Researchpp 469-481Zhang, Z., Wu, Q., Zhang, C., Wang, Y., Li, Y., and Zhang, Q. (2015). "Effect of inlet velocity on heat transfer process in a novel photo-fermentation biohydrogen production bioreactor using computational fluid dynamics simulation," BioRes. 10(1), 469-481.AbstractArticlePDF

    Temperature is one of the most important parameters in biohydrogen production by way of photo-fermentation. Enzymatic hydrolysate of corncob powder was utilized as a substrate. Computational fluid dynamics (CFD) modeling was conducted to simulate the temperature distribution in an up-flow baffle photo-bioreactor (UBPB). Commercial software, GAMBIT, was utilized to mesh the photobioreactor geometry, while the software FLUENT was adopted to simulate the heat transfer in the photo-fermentation process. The inlet velocity had a marked impact on heat transfer; the most optimum velocity value was 0.0036 m•s-1 because it had the smallest temperature fluctuation and the most uniform temperature distribution. When the velocity decreased from 0.0036 m•s-1 to 0.0009 m•s-1, more heat was accumulated. The results obtained from the established model were consistent to the actual situation by comparing the simulation values and experimental values. The hydrogen production simulation verified that the novel UBPB was suitable for biohydrogen production by photosynthetic bacteria because of its uniform temperature and lighting distribution, with the serpentine flow pattern also providing mixing without additional energy input, thus enhancing the mass transfer and biohydrogen yield.

  • Researchpp 482-498Tenorio, C., Moya, R., Tomazello Filho, M., and Valaert, J. (2015). "Quality of pellets made from agricultural and forestry crops in Costa Rican tropical climates," BioRes. 10(1), 482-498.AbstractArticlePDF

    Pellets may be produced with different types of agriculture or forestry crops in Costa Rica. This work evaluated the energy, physical, and mechanical properties of pellets fabricated from 12 types of agricultural and forestry crops (Ananas cumosos, Arundo donax, Coffea arabica, Cupressus lusitanica,empty fruit bunch and oil palm mesocarp fiber of the fruit of Elaeis guineensis, Gynerium sagittatum, Pennisetum purpureum, Phyllostachys aurea, Saccharum officinarum, Sorghum bicolor,and Tectona grandis), and similarities among these crops were established by multivariate principal component analysis. High variation was found in the pellet properties. The energy evaluation revealed that C. lusitanica and P. aurea are the crops with the best qualities for fuel use because of their high calorific values (from 16807 kJ/kg and 19919 kJ/kg, respectively) and low ash content (1.03% and 3.39%, respectively). As for physical properties, most crops exhibited values within the range noted by several authors and standards. All 12 pellet crops displayed high durability (from 72.12% to 92.98%) and compression force (from 295.18 N to 691.86 N). Moreover, the evaluation of crop similarities allowed the determination of four group combinations. Within these groups, C. lusitanica, P. aurea, and G. sagittatum had similar energy qualities and the best caloric characteristics.

  • Researchpp 499-509Li, R., Ekevad, M., Guo, X., Ding, J., and Cao, P. (2015). "Effect of pressure, feed rate, and abrasive mass flow rate on water jet cutting efficiency when cutting recombinant bamboo," BioRes. 10(1), 499-509.AbstractArticlePDF

    The impact of varying pressure, feed rate, and abrasive mass flow rate on the efficiency of an abrasive water jet cutting process was studied in this work. Recombinant bamboo samples with thicknesses of 5, 10, and 15 mm were cut by the abrasive water jet. The upper kerf width, lower kerf width, and the ratio of the upper kerf width to lower kerf width were chosen as the efficiency parameters. Mathematical models were developed to describe the relationship between the input process parameters and the efficiency parameters. The arrangement of experiments and analysis of results were performed based on response surface methodology. The evaluated model yielded predictions in agreement with experimental results.

  • Researchpp 510-526Kim, B. J., Huang, R., Xu, X., Lee, S. Y., Kunio, J., and Wu, Q. (2015). "Sound transmission properties of mineral-filled high-density polyethylene (HDPE) and wood-HDPE composites," BioRes. 10(1), 510-526.AbstractArticlePDF

    Wood plastic composites (WPCs) offer various advantages and potential as a competitive alternative to conventional noise barriers. For this purpose, the influence of composite formulation on the sound transmission loss (TL) of WPCs needs to be fully understood. In TL testing, stiffness and surface density are major factors influencing the sound insulation property of filled plastics and WPCs. Experimental TL values decreased as sound frequency increased; and the TL values increased after passing a certain frequency level. The comparison of experimental TL curves among filled composites showed that the addition of fillers led to an increase in resonance frequency and TL values. However, at high filling levels, the stiffness decrease led to TL reductions. The experimental TL curves of filled composites, composed of mass law and stiffness law predictions, were well approximated with their combined TL predictions.

  • Researchpp 527-537Li, X., Zhang, J., Liao, C., Chen, H., Luo, Y., and Li, X. (2015). "Mathematical simulation and design of a rectangular cavity of microwave pretreatment equipment used for wood modification," BioRes. 10(1), 527-537.AbstractArticlePDF

    Wood pretreated by high-intensity microwaves was theoretically studied based on the Maxwell electromagnetic field equations and the heat and mass transfer mechanism of wood. The effects of feeding modes on the temperature field uniformity and energy efficiency were studied using the finite element method, and optimized parameters of the rectangular microwave resonant cavity were achieved. The results show that the feeding modes had a great effect on the temperature field uniformity of the wood and the energy efficiency. Compared to the side single-port, the upper single-port, and the upper-under port feeding modes, the two-side ports feeding mode was the best for temperature field uniformity and energy efficiency.

  • Researchpp 538-547Chen, T., Niu, M., Xie, Y., Wu, Z., Liu, X., Cai, L., and Zhuang, B. (2015). "Modification of ultra-low density fiberboards by an inorganic film formed by Si-Al deposition and their mechanical properties," BioRes. 10(1), 538-547.AbstractArticlePDF

    To improve mechanical properties of ultra-low density fiberboards (ULDFs), Si-Al compounds were mixed together with fibers during preparation of ULDFs, forming a thin film on the surface of the fibers via hydrogen bonding. This work mainly optimized two proposed methods in which the inorganic thin film was assembled on the surface of fibers, in terms of its effect on the mechanical properties of fibers. Microstructural characterization (such as micromorphology and elemental distribution, chemical bonding, and crystalline phase) of Si-Al compounds and ULDFs was done to evaluate the effects. The results revealed that an inorganic thin film (probably Al2O3-SiO2) covered the surface of the fibers. Compared with the control specimen, the modulus of elasticity, modulus of rupture, and internal bond strength of the specimen treated by the sol-gel process increased from 3.87 MPa to 13.19 MPa, 0.05 MPa to 0.16 MPa, and 0.010 MPa to 0.025 MPa, respectively. Based on its higher mechanical properties, a combined sol-gel method was judged to be better for enhancement of fibers than a separate deposition method.

  • Researchpp 548-565Gao, J., Ti, C., and Chen, N. (2015). "Environmental comparison of straw applications based on a life cycle assessment model and emergy evaluation," BioRes. 10(1), 548-565.AbstractArticlePDF

    Straw is considered to be a renewable resource for bioenergy and biomaterial. However, about 70% of straw is burned in fields, which causes serious air pollution in China. In this study, a life cycle assessment (LCA) model, together with emergy evaluation, was built to compare four straw applications after harvest vs. direct burning, including bioethanol (BE), combined heat and power plant (CHP), corrugated base paper (CP), and medium-density fiberboard (MDF). The results showed that BE and MDF would avoid greenhouse gas (GHG) emissions by 82% and 36%, respectively, while CHP and CP would emit 57% and 152% more GHG , respectively, compared with direct straw burning. Bioethanol had the highest renewability indicator (RI) of 47.7%, and MDF obtained the greatest profit of 657 Yuan·bale-1. The applications CHP and CP had low RI (< 10.3%) and profit (< 180 Yuan·bale-1). Due to water recycling and electrical power as a coproduct, BE had the lowest value (3 × 1011 sej·Yuan-1) of EmPM (emergy per unit money profit); the EmPM value of CP was 18.6 times higher than that of BE. The four straw applications would also greatly reduce particles emission (57 to 98%) to air. BE was judged to be the most environmentally friendly application among the four straw applications. Imposing a carbon tax would encourage investment in BE, but discourage the applications CHP and CP.

  • Researchpp 566-574Zhang, J., Zhang, W., and Zhang, Y. (2015). "Pore structure characteristics of activated carbon fibers derived from poplar bark liquefaction and their use for adsorption of Cu(II)," BioRes. 10(1), 566-574.AbstractArticlePDF

    In this work, wood bark was liquefied to prepare activated carbon fibers, which were obtained through melt-spinning, stabilization, carbonizing, and stream activation. The effects of varying activation temperature on the pore structure and the adsorption capacity of the liquefied wood bark activated carbon fibers (LWBACFs) were studied using analysis of nitrogen adsorption-desorption isotherms and static adsorption of copper (II) ions from aqueous solution. The results indicated that higher specific surface area was obtained as the activation temperature increased. The specific surface area reached a maximum of 1962 m2/g with an average pore diameter of approximately 2 nm. Carbonization at 200 °C played an important role in the formation of pore structure. The adsorption of copper by LWBACFs was high, with a peak of 15 mg/g. All parameters showed that LWBACFs performed well in the adsorption of micropores.

  • Researchpp 575-587Li, H., Deng, Y., Ye, H., Xiao, L., and Qiu, X. (2015). "Effect of temperature on polyelectrolyte expansion of lignosulfonate," BioRes. 10(1), 575-587.AbstractArticlePDF

    The temperature effect on the polyelectrolyte expansion of sodium lignosulfonate (SL) was studied in the range of 20 to 38 °C. A narrow molecular-weight distribution fraction of sodium lignosulfonate was first obtained by gel column chromatography, which was suitable for the hydrodynamic radius (Rh) measurement by dynamic light scattering (DLS). Dynamic light scattering experiments showed that the hydrodynamic radius of sodium lignosulfonate decreased with increasing temperature. Using a quartz crystal microbalance (QCM) and atomic force microscopy (AFM), it was found that the adsorbed sodium lignosulfonate film lost water with increasing temperature and reabsorbed water with decreasing temperature. Surface tension and contact angle experiments showed that there were more hydrophobic groups on the surface of the sodium lignosulfonate molecule as the temperature increased. It can be concluded that the sodium lignosulfonate molecule shrank and became more hydrophobic with increasing temperature. Analysis suggests that the decreasing of the hydrogen-bond interactions between the sodium lignosulfonate molecule and water molecules with increasing temperature is the primary reason for the molecular conformation change of sodium lignosulfonate.

  • Researchpp 588-596Akhtar, J., Teo, C. L., Lai, L. W., Hassan, N., Idris, A., and Aziz, R. A. (2015). "Factors affecting delignification of oil palm empty fruit bunch by microwave-assisted dilute acid/alkali pretreatment," BioRes. 10(1), 588-596.AbstractArticlePDF

    Microwave-assisted dilute acid/alkali pretreatment is an efficient and rapid method of removing lignin and hemicellulose, however, the optimized parameters for the maximum efficiency have to date not been presented in the literature. The purpose of this study was to determine those conditions by examining the effects of three factors:microwave power, temperature, and time on delignification in microwave-assisted dilute acid/alkali pretreatment. For the control condition of conventional pretreatment (CP), empty fruit bunches (EFBs) were soaked in 2.5 M NaOH for two hours in the autoclave. In the experimental condition, EFB were first soaked in dilute sulfuric acid with conventional autoclave heating, which removed 90% of their hemicellulose. The acid-treated EFBs were then soaked in 2.5 M NaOH solution and microwaved at different conditions: microwave power (700 – 100 watts), time (60 – 90 min), and temperature (80 -110 °C). The amount of acid-insoluble lignin was determined by Klason method. Microwave-Alkali (Mw-A) pretreatment was modeled until it attained maximum delignification. More than twice the rate of delignification that is,71.9% was attained with microwave-assisted alkali/acid pretreatment of 900 W microwave power at 110 °C for 80 min compared to 34.6% with conventional pretreatment.

  • Researchpp 597-612Antes, R., and Joutsimo, O. P. (2015). "Effect of modified cooking on bleachability of Eucalyptus globulus and Eucalyptus nitens," BioRes. 10(1), 597-612.AbstractArticlePDF

    This work evaluates the effect of SuperBatch™ (SB), CompactCooking™ (CC), and Lo-Solids™ (LS) modified cooking concepts on pulp bleachability of Eucalyptus globulus and Eucalyptus nitens. E. globulus wood samples presented higher amounts of cellulose and E. nitens higher amounts of hemicellulose and acetone extractives. The same trend was observed in brownstock and in fully-bleached pulps. E. globulus wood sample presented lower amounts of lignin and higher S/G ratio than E. nitens. In the brownstock pulps, the amount of Hexenuronic Acids (HexA) and total lignin for E. globulus and E. nitens did not present significant difference variation in the contribution to kappa number 17±0.5. No significant differences were found in intrinsic viscosity among modified cooking methods in unbleached and in fully-bleached pulps. For both species, the CC produced pulps with the highest hemicelluloses content after cooking to the fully-bleached pulp. In this work, one cannot observe differences in bleachability of E. globulus and E. nitens caused by different modified cooking concepts.

  • Researchpp 613-621Mirbolouk, P., and Roohnia, M. (2015). "Evaluation of dynamic modulus of elasticity of medium density fiberboard panel from longitudinal vibration tests on specimens," BioRes. 10(1), 613-621.AbstractArticlePDF

    It is preferred to perform conformity assessment of wood-based panels on the whole panel without cutting it down to smaller pieces. The modulus of elasticity, a mechanical property of wood, was determined by longitudinal vibration testing with the full-size panel, and the results were compared with results of tests of prismatic beams. The Brancheriau’s correction coefficient was used to compensate for errors from cross-sectional dimension variations and errors from Poisson’s ratio. Longitudinal excitation of the panels along the length was shown to be successful in evaluating the modulus of elasticity. However, strong correlations obtained from plate and beam comparisons along the width of the panels are promising.

  • Researchpp 622-637Zhao, X., Gong, J., Zhou, S., Yang, K. O., Song, X., Fu, C., Xu, L., and Qu, M. (2015). "Effect of fungal treatments of rape straw on chemical composition and in vitro rumen fermentation characteristics," BioRes. 10(1), 622-637.AbstractArticlePDF

    The use of rape straw in ruminant production is limited by its high lignin content and low ruminal degradability. White rot fungi are the most efficient known degraders of lignin. Four white rot fungi were investigated for their potential to degrade lignin and improve rumen fermentation of rape straw. Solid state fermentation of the straw was carried out for 0 to 30 days to determine changes in chemical composition and in vitro rumen fermentation. Results showed that Phanerochaete chrysosporium and Lentinula edodes degraded about 45% of lignin and enhanced the in vitro organic matter digestibility (IVOMD) and volatile fatty acid production; however, about 55% of the cellulose was lost after 30 days of incubation. Ceriporiopsis subvermispora and Phlebia acerina degraded a fraction (< 30%) of lignin and cellulose, but inhibited ruminal fermentation. Fungal incubation increased the chitin content of rape straw. Regression analysis showed that the IVOMD increase depended on the combined action of neutral detergent fiber loss and chitin content increase in rape straw. This study indicates that considerations of the conversion of rape straw into ruminant feed with white-rot fungi should take into account the degradation of lignin, fiber loss, and the chitin produced along with the growth of fungi.

  • Researchpp 638-646Liu, Y., Gao, J., Guo, H., Pan, Y., Zhou, C., Cheng, Q., and Via, B. K. (2015). "Interfacial properties of loblolly pine bonded with epoxy/wood pyrolysis bio-oil blended system," BioRes. 10(1), 638-646.AbstractArticlePDF

    The bonding interface of loblolly pine veneers cured with epoxy/wood pyrolysis bio-oil resins was studied. The shear strength of the adhered strands was calculated to examine the effect of bio-oil addition on epoxy resin performance. The chemical structure, curing behavior, and microstructure were investigated to analyze the interaction between wood substrate and resins. Results showed that the strength of pine wood-resin joints gradually decreased as more bio-oil was added. However, this effect was not apparent when the substitution rate was lower than 30%. ATR-FTIR analysis confirmed that complex chemical reactions take place between wood constituents and epoxy/bio-oil resins involved in the cross-linking at the interface. The reaction degree of -OH and C-O-C functional groups plays a key role in regulating the bonding stress of the wood bond line. The addition of bio-oil accelerated the polycondensation cross-linking process, resulting in a decreased cure temperature. SEM and optical microscopy showed that the epoxy/bio-oil resin formed gel nails in the pit and tracheid gaps, leading to the closing of the capillaries of the wood’s cell walls and the colloidal interface extending into the timber micro-capillary system.

  • Researchpp 647-659Zhang, J., Wang, Z., Du, M., Yao, X., and Hu, L. (2015). "Physicochemical properties of camellia nut shell and its thermal degradation characteristics," BioRes. 10(1), 647-659.AbstractArticlePDF

    Camellia nut shell (CNS) is known as an important bio-resource that has great potential as a biomaterial. The elemental composition, chemical structure, crystallinity, and pyrolysis characteristics were analyzed in this paper for six species of CNS. The concentration of organic carbon, N, K, and Na in CNS ranges from 44.40 to 48.60%, 2.91 to 4.42 mg.g-1, 7.67 to 13.80 mg.g-1, and 0.02 to 0.26 mg.g-1, respectively. The content of lignin, cellulose, hemicellulose, and ash varies between 30.07 and 36.23%, 13.87 and 20.95%, 35.15 and 49.34%, as well as 2.00 and 4.75%, respectively. Camellia nut shell cellulose crystalline structure belongs to typical cellulose type I, and the cellulose crystallinity index for the six species ranges from 37.4 to 62.3%. The CNS pyrolysis process can be divided into three phases, and the substantial degradation occurs within the temperature range of 200 to 430 °C, with nearly 60% loss of weight. The temperature could be reduced greatly during pyrolysis under acidic conditions with PEG 400/glycerol as a solvent. The degradation rate was impacted by K concentration. Increasing cellulose crystallinity negatively affected the degradation rate.

  • Researchpp 660-671Huang, X. D., Hse, C. Y., and Shupe, T. F. (2015). "Evaluation of the performance of the composite bamboo/epoxy laminated material for wind turbine blades technology," BioRes. 10(1), 660-671.AbstractArticlePDF

    Global energy sources such as coal and oil are limited, and the burning of such fossil resources creates pollution problems. Wind energy offers one of several promising clean alternatives to carbon-based fuels. However, the composite materials currently available for producing wind turbine blades cannot accommodate the scale-up of wind energy due to their high price and disposal challenges (e.g., carbon fiber/epoxy laminated, fiber-reinforced plastics) or environmental costs (e.g., wood/epoxy laminate materials derived from large-diameter natural forest wood). The purpose of this study was to explore the advantages of the composite bamboo/epoxy laminated material as a more cost-effective, sustainable alternative. Applying the classical theory of composite laminated plates, this study tested a prediction model of the composite bamboo/epoxy laminated material’s elastic modulus values. The model accurately predicted the end product’s elastic modulus values according to the single bamboo board’s elastic modulus values and its manner of assembly, without destroying the material’s basic structure and integrity. The composite bamboo/epoxy laminated material was judged to be less expensive than carbon fiber/epoxy laminated, fiber-reinforced plastics and to have advantageous mechanical properties relative to conventional wood/epoxy laminate materials.

  • Researchpp 672-683Alvarez, C., Rojas, O. J., Rojano, B., and Ganán, P. (2015). "Development of self-bonded fiberboards from fiber of leaf plantain: Effect of water and organic extractives removal," BioRes. 10(1), 672-683.AbstractArticlePDF

    Adhesive-free fiberboards can be self-bonded through high temperature thermo-compression processes. To achieve it, treatments such as steam explosion/injection, as well as chemical and enzymatic oxidation have been implemented. However, the role of extractive components in the structure and cohesiveness of fiberboards has not been fully understood. In this work fibers of leaf plantain were treated with organic solvents and with hot water to remove the extractives, and were then employed to produce self-bonded fiberboards. Treated fibers were characterized by thermogravimetric analysis, electronic paramagnetic resonance, and antioxidant capacity. The mechanical strength of the fiberboards evaluated by three point flexural tests, decreased when fibers were extracted with aqueous solvents, and increased after treatment with organic ones. This can be explained by the effect of water extractives in reducing the initial degradation temperature, and in retaining free stable radicals generated during thermo-compression. In the case of the organic extractive fraction, this inactivates the fibers, which impairs close contact between polar groups and thus decreases the mechanical properties of the fiberboards. According to the results, it is possible to increase the mechanical properties of self-bonded fiberboards by changing the concentration of polar and low molecular weight phenolic compounds.

  • Researchpp 684-696Chen, Y., Wu, Q., Huang, B., Huang, M., and Ai, X. (2015). "Isolation and characteristics of cellulose and nanocellulose from lotus leaf stalk agro-wastes," BioRes. 10(1), 684-696.AbstractArticlePDF

    Valorization of lotus leaf stalks (LLS) produced as an abundantly available agro-waste was achieved through the extraction of value-added nanocellulose. Nanofibrillated cellulose (NFC) was successfully prepared from LLS by using chemical pretreatment combined with high-intensity ultrasonication. The morphological characteristics of the chemically purified LLS cellulose microfibrils were characterized by optical microscopy and MorFi fiber analysis. Fourier transform infrared (FTIR) spectroscopy indicated the extensive removal of non-cellulosic components after chemical pretreatment. The transmission electron microscopy (TEM) results revealed agglomeration of the developed individual NFC, with a width of 20 ± 5 nm and length on a micron scale, into a network-like feature. X-ray diffraction results showed that the resulting NFC had a cellulose I crystal structure with a high crystallinity (70%). The NFC started to degrade at around 217 °C, and the peak rate of degradation occurred at 344 °C. Nanofibrils obtained from LLS have great potential as reinforcement agents in nanocomposites.

  • Researchpp 697-708Yao, J., Ma, L., Lu, W., and Tan, H. (2015). "Tensile property analysis and prediction model building for coir rope reinforced unsaturated polyester composite," BioRes. 10(1), 697-708.AbstractArticlePDF

    Because of the light weight and environmental advantages of natural fibers, an increasing amount of natural fibers have been used to replace synthetic fibers in reinforced unsaturated polyester (UPE). Because of the impact property advantage of coir fibers, coir toughened UPE composites can achieve excellent impacting toughness, but at the cost of a lower tensile performance. In order to get the better comprehensive performance, the tensile strength must be maintained in a higher level, so coir ropes as an appropriate reinforced form were added to UPE matrix. The different weight-percent contents for the coir rope addition were set to achieve coir rope reinforced UPE composites with different coir contents. The tensile test results showed increasing tensile strength with the increased content of coir ropes. To reasonably and accurately predict the composite performance, taking the original performance prediction model based on a continuous reinforced fiber composite (using the Classical Mixed Law as a reference) and assuming each coir rope was ideally continuous fiber, the destructive principle of coir rope reinforced UPE composite under the action of tensile load was analyzed and the tensile failure mechanics model was improved. According to the experimental proof, the new model can be proven to have higher precision accuracy, which can provide new train of thought for the building of the theoretical models for natural fiber reinforced composites, thus guiding the actual production application.

  • Researchpp 709-720Wang, W., Meng, X., Min, D., Song, J., and Jin, Y. (2015). "Effects of green liquor pretreatment on the chemical composition and enzymatic hydrolysis of several lignocellulosic biomasses," BioRes. 10(1), 709-720.AbstractArticlePDF

    Pretreatment of biomass is an extremely important step in a commercial biorefinery. For realization of lignocellulosic biomass as an alternative fuel source to occur, a fundamental understanding and critical investigation of the chosen pretreatment are essential. In this work, green liquor (GL) pretreatment of four plant species, namely Masson pine, poplar, moso bamboo, and miscanthus, was investigated to understand its effect on the chemical composition and enzymatic hydrolysis of different lignocellulosic materials. The results indicated that herbaceous materials exhibited better delignification selectivity in GL pretreatment than woody materials according to the order: miscanthus > moso bamboo > poplar > Masson pine. The effect of GL pretreatment on the enzymatic sugar yield was rather different depending on the varieties of lignocellulosic materials. Higher lignin removal with less polysaccharide degradation during GL pretreatment improved the enzymatic sugar yield.

  • Researchpp 721-731Gominho, J., Lourenço, A., Miranda, I., and Pereira, H. (2015). "Radial and axial variation of heartwood properties and extractives in mature trees of Eucalyptus globulus," BioRes. 10(1), 721-731.AbstractArticlePDF

    Mature 40-year-old trees of Eucalyptus globulus harvested in Portugal were studied to determine the heartwood development and variation of basic density and extractives content at different stem height levels. The heartwood radius decreased regularly from bottom to top in all the trees: for instance 22.2 cm, 13.0 cm, and 10.4 cm, respectively, at the 0%, 35%, and 60% height levels of tree 1. The average sapwood thickness was 2.8 cm at the stem base. The mean basic density fell in a range between 0.607 g cm-3 and 0.782 g cm-3 and was highest in the outer heartwood at all height levels. The total content of extractives varied axially and radially along the stem. It decreased until the 35% height level, and then it remained approximately constant upwards. The extractives content increased radially from the sapwood to the inner heartwood (6.2% to 12.5% at the base). Ethanol-soluble compounds were the major fraction at the base: 4.9%, 8.4%, and 10.9% of dry mass, respectively, for sapwood, outer heartwood, and inner heartwood. The non-polar extractives were obtained by dichloromethane extraction in very low amounts.

  • Researchpp 732-749Chowdhury, Z. Z., Hamid, S. B. A., and Zain, S. M. (2015). "Evaluating design parameters for breakthrough curve analysis and kinetics of fixed bed columns for Cu(II) cations using lignocellulosic wastes," BioRes. 10(1), 732-749.AbstractArticlePDF

    A continuous adsorption study for removal of Cu(II) cations from wastewater using a fixed-bed column was conducted. A granular carbonaceous activated adsorbent produced by carbonization of the outer rind, or exocarp, of mangostene fruit shell was used for column packing. The effects of feed flow rate, influent cation concentration, and bed depth on the breakthrough curve were investigated at pH 5.5. Experimental analysis confirmed that the breakthrough curves were dependent on flow rate, initial concentration of Cu(II) cations, and bed height related to the amount of activated carbon used for column packing. Thomas, Yoon–Nelson, and Adams–Bohart models were applied to analyze the breakthrough curves at different conditions. Linear regression analysis of experimental data demonstrated that Thomas and Yoon–Nelson models were appropriate to explain the breakthrough curve, while the Adams–Bohart model was only applicable to predict the initial part of the dynamic process. It was concluded that the column packed with fruit rind based activated carbon can be used to treat Cu(II)-enriched wastewater.

  • Researchpp 750-759Wang, S., Wang, M., and Chen, F. (2015). "Synthesis of poly[vinylamine-co-(sodium acrylate)] and its application as a paper strength additive," BioRes. 10(1), 750-759.AbstractArticlePDF

    The synthesis of poly[vinylamine-co-(sodium acrylate)] [P(VAm-co-NaAA)] and its application as a paper strength additive have been investigated. P(VAm-co-NaAA) was synthesized by the alkaline hydrolysis of poly[N-vinylformamide-co-(acrylic acid)] (PNVFAA). The influence of polymer concentration, hydrolysis temperature, and NaOH concentrations on the extent of hydrolysis were examined experimentally. The hydrolysis was 100% completed under the following conditions: hydrolysis temperature 80 °C, hydrolysis time 8 h, polymer concentration 2%, and NaOH concentration 0.045 mol/g of PNVFAA. P(VAm-co-NaAA) obtained in this manner increased the tensile strength and folding endurance of paper by 44% and 48%, respectively, and the strength increase was greater than that obtained with the commercially available polyvinylamine.

  • Researchpp 760-771Zhou, H., Zhu, H., Yang, X., Zhang, Y., Zhang, X., Cui, K., Shao, L., and Yao, J. (2015). "Temperature/pH sensitive cellulose-based hydrogel: Synthesis, characterization, loading, and release of model drugs for potential oral drug delivery," BioRes. 10(1), 760-771.AbstractArticlePDF

    Due to their unique physical and chemical properties, hygrogels have been applied in various industrial and agricultural fields. Biomedicine is another high value-added and attractive area for the application of hydrogels. For this reason, a novel temperature/pH sensitive cellulose based hydrogel was synthesized based on the cellulose from Phyllostachys heterocycla. Its synthesis conditions were optimized, and its loading and release capabilities for model drugs were investigated in detail. The resultant data showed that the synthesized hydrogel exhibited the highest swelling ratio at 37 °C and pH 7.4, corresponding to the temperature and pH of the human intestinal environment. The hydrogel held excellent load performance for model drug MB and an obvious temperature dependence at 37 °C (body temperature of human) when the model drug was released from it. These positive results suggest that the synthesized temperature/pH sensitive cellulose-based hydrogel has a great potential for oral drug delivery applications.

  • Researchpp 772-781Todaro, L., Rita, A., Moretti, N., Cuccui, I., and Pellerano, A. (2015). "Assessment of thermo-treated bonded wood performance: Comparisons among Norway spruce, common ash, and turkey oak," BioRes. 10(1), 772-781.AbstractArticlePDF

    Polyvinyl acetate (PVA) exhibits fine adhesion qualities when bonded to wood. However, when using thermo-treated wood, a number of different unstudied factors (such as the water stress condition) influence the wood bonding effectiveness. The main goal of this study was to evaluate how different treatments affect the shear bonding strength for three cases of thermo-vacuum treated woods. Wood from both Norway spruce (Picea abies Karst.) and common ash (Fraxinus excelsior L.) was thermo-treated at 190 °C for two hours under vacuum conditions (250 mbar). Turkey oak (Quercus cerris L.) logs were separately steamed at 110 °C for 24 h, then thermo-vacuum treated at 160 °C for three hours. The bonding shear strength between the PVA adhesive and treated wood was evaluated using water stress condition. The results were compared with the adhesive bond line properties of the untreated wood. The shear strength and wettability of the produced material were measured. Tests for the shear resistance, performed in accordance with the standard DIN EN 204, revealed dissimilar behavior as well as the influence of treatment schedules for the different wood species. Consequently, the tests performed allowed a detailed characterization of the effect of the thermo-vacuum process on the bonding quality of three common woods in different water stress conditions.

  • Researchpp 782-792Zhang, J., Amirou, S., Essawy, H. A., Pizzi, A., Gao, Q., and Li, J. (2015). "Hyperbranched poly(amidoamine)s as additives for urea formaldehyde resin and their application in particleboard fabrication," BioRes. 10(1), 782-792.AbstractArticlePDF

    Three types of hyperbranched poly(amidoamine)s (PAMAMs), namely HB(MA-EDA)1, HB(MA-EDA)3, and HB(MA-DETA)1.2, were synthesized and used as modifiers for urea-formaldehyde (UF) resin. Particleboards bonded with these modified UF resins were fabricated and evaluated. The results showed that these PAMAMs caused some adverse effects on UF resin performance. The main problems of PAMAMs were their high buffer capacity and high pH values, which are attributed to the peripheral amino groups at the terminals, both of which had a serious negative influence on UF resin curing. These findings were supported by the gel time measurements in parallel with a predictive investigation on the resins using thermomechanical analysis (TMA). The gel time was prolonged, and the maximum modulus of elasticity (MOE) values decreased with the addition of HB(MA-EDA)3. The use of a strong acid curing agent (HCOOH) could reduce the gel time into a normal range; however the performance of the corresponding particleboards still deteriorated. Therefore, these PAMAMs are considered not suitable for the modification of UF resin when applied as final additives. Beyond all expectations, the modified UF resin that employed very finite amounts of HB(MA-EDA)1 as a pH regulator instead of NaOH yielded a considerable upgrade in performance of the produced particleboards.

  • Researchpp 793-808Zeidler, A., Salem, M. Z. M., and Borůvka, V. (2015). "Mechanical properties of grand fir wood grown in the Czech Republic in vertical and horizontal positions," BioRes. 10(1), 793-808.AbstractArticlePDF

    Strength properties were evaluated for Grand fir wood (Abies grandis /Douglas/ Lindl.), a North American species that is considered to be a promising species for the Central European forestry industry. The bending, compression, and impact strengths of wood from Grand fir trees grown in the Czech Republic area were tested, including their variability within a stem and correlation to wood density. The average values of the compression strength reached 39.577 MPa; the bending strength was 78.119 MPa, the impact strength was 4.186 J/cm2, and the density was 410.267 kg/m3. The greatest dependence of the strength characteristics on the evaluated density was shown in the case of bending at the vertical bottom position (r = 0.95). Compression strength values were observed to highly correlate with the density at vertical positions (bottom and middle) in the first site (r = 0.98). The values of the correlations between density and impact strength were observed to be moderate or poor in the vertical position, where a good value was shown in the middle position (r = 0.87). The results of the study suggest that Grand fir is a satisfactory substitute for indigenous species of fir in the Czech Republic; with respect to bending strength and toughness, it can replace the most important commercial conifer, spruce.

  • Researchpp 809-821Mao, H., Zhou, D., Hashisho, Z., Wang, S., Chen, H., and Wang, H. (2015). "Preparation of pinewood- and wheat straw-based activated carbon via a microwave-assisted potassium hydroxide treatment and an analysis of the effects of the microwave activation conditions," BioRes. 10(1), 809-821.AbstractArticlePDF

    This study explored the effect of activated carbon preparation conditions on their adsorption performance. Pinewood and wheat straw were used as source materials to prepare activated carbon via a fast activation process using KOH and microwave heating. The iodine numbers and carbon yields were determined to evaluate the adsorption properties of the activated carbon. The effects of various KOH/char mass ratios, particle sizes, humidity levels, and microwave heating times on the physical characteristics of the activated carbon were investigated. The iodine number and yield and SEM images were used to characterize the activated carbon. Small particle sizes, the presence of humidity in the purge gas, and high KOH/char ratios resulted in higher iodine numbers. The best activated carbons were obtained using a KOH/char ratio of 3.0, a microwave power of 600 W, a radiation time of 30 min, and a particle size of 0.1 to 0.42 mm in a humid environment; these carbons showed iodine numbers of 2208 mg/g (pinewood activated carbon) and 1420 mg/g (wheat straw activated carbon), with carbon yields of 73% and 52%, respectively. Longer microwave heating times increased the iodine number. The iodine numbers and yields of the pinewood activated carbons were much higher than those of their wheat straw counterparts.

  • Researchpp 822-838Ali, M. E., Yong, C. K., Ching, Y. C., Chuah, C. H., and Liou, N.-S. (2015). "Effect of single and double stage chemically treated kenaf fibers on mechanical properties of polyvinyl alcohol film," BioRes. 10(1), 822-838.AbstractArticlePDF

    The physico-mechanical properties of lignocellulosic kenaf fiber reinforced polyvinyl alcohol (PVA) biocomposite films were investigated. To improve the properties of the biocomposite, kenaf fibers were chemically treated separately in a single stage (with Cr2(SO4)3×12(H2O)) and double stages (with CrSO4 and NaHCO3) to improve the adhesion and compatibility between the kenaf fiber and PVA matrix. PVA was reinforced with various compositions of chemically treated kenaf fiber by using a solution casting technique. Microstructural analyses and mechanical tests were subsequently conducted. Scanning electron microscopic analysis indicated that chemical treatment improved the uniformity distribution of kenaf fiber within the PVA matrix. FTIR and XRD analyses confirmed the presence of chromium on the fiber surface. The tensile strength of PVA reinforced with chemical treated kenaf fiber was found to be higher than those reinforced with untreated kenaf. The Young’s modulus, flexural strength, and flexural modulus increased with fiber loading for both untreated and treated kenaf fiber reinforced PVA films. The double stage treated kenaf fiber showed better mechanical properties and lower moisture uptake than the single stage treated kenaf fiber.

  • Researchpp 839-850Zhai, R., Yuan, Y., and Zhou, X. (2015). "Preparation of wet strength paper from filter paper with NaOH-thiourea-urea aqueous solution," BioRes. 10(1), 839-850.AbstractArticlePDF

    In this work, wet strength paper was prepared from quantitative filter paper pretreated with NaOH-thiourea-urea aqueous solution. The effects of alkali concentration, soaking time, freezing time, and washing time were evaluated through single factor experiments. The optimum conditions were found to be an alkali concentration of 8%, soaking time of 2 seconds, freezing time of 15 minutes, and washing time of 10 minutes. Under these conditions, the wet tensile strength of the modified paper could be increased to 33% of the dry tensile strength and 400% of the wet tensile strength of the body paper. Also, the wet burst strength could be improved to 200% of the dry burst strength and 2400% of the wet burst strength of the body paper. However, there were no significant effects on the structure of the functional groups or crystalline region. Also, there was no toxic material released during the treatment, and the treatment solution was recyclable and environmentally friendly.

  • Researchpp 851-865Lee, S. H., Lee, H. L., and Youn, H. J. (2015). "Adsorption of xylan onto cellulose fibers pretreated with cationic polyelectrolyte and its effect on paper properties," BioRes. 10(1), 851-865.AbstractArticlePDF

    Xylan is known as a strength-enhancing agent for paper. However, it is difficult to adsorb xylan onto cellulose fibers because it carries the same negative charge as fibers. Therefore, either cationization of xylan or addition of cationic polyelectrolyte is required to maximize the effect of xylan use. In this study, cationic polyelectrolyte was used to promote xylan adsorption onto cellulose fiber. The effect of the polyelectrolyte type on the successive adsorption of xylan and its influence on paper properties was examined. The mechanism for improving paper strength by xylan adsorption on polyelectrolyte pre-formed layers was investigated through the viscoelastic properties of the preformed layers on model cellulose films using Quartz Crystal Microbalance with Dissipation (QCM-D). Both tensile and tear indices of paper were improved with the adsorption of xylan onto pulp fibers. It was suggested that the adsorbed xylan onto the polyelectrolyte preformed layer formed a complex layer that gave rise to a large contact area between xylan and fiber. The increase in the physical strength of paper depended on the structure of the polyelectrolyte-xylan layers. Highly charged cationic polyelectrolytes that form a flat adsorption layer gave a relatively lower increase in physical properties. On the other hand, thicker and more viscous adsorbed layers improved paper strength significantly.

  • Researchpp 866-876Fekiač, J., Zemiar, J., Gaff, M., Gáborík, J., Gašparík, M., and Marušák, R. (2015). "3D-moldability of veneers plasticized with water and ammonia," BioRes. 10(1), 866-876.AbstractArticlePDF

    The 3D-moldability of veneers, as opposed to the moldability of plastic or other materials, is limited because of the characteristics of wood. Veneers can be modified by physical, chemical, or mechanical treatment. We chose water and ammonia-water solutions. After treatment for an established time, the moldability of veneers was examined. The level of concave deflection of a test piece of punch-molded veneer was assessed. Three sets of test pieces were tested by dipping in cold water (20 °C), hot water (95 °C), or a 25% solution of ammonia, for different durations of time. The results showed that the 3D-moldability of veneers increased by 66 to 119% after plasticization by a 25% solution of ammonia, unlike the unmodified veneers with a moisture content of 7.65%. The increase in moldability was significantly higher in comparison to the veneers modified by dipping in cold water (20 °C) and hot water (95 °C). Futhermore, the relationship between the moisture content of the veneers after their modification/plasticization, the level of concave deflection, and the molding force in relation to the level of concave deflection were examined.

  • Researchpp 877-886Li, G., Fu, S., Zhou, A., and Zhan, H. (2015). "Improved cellulose yield in the production of dissolving pulp from bamboo using acetic acid in prehydrolysis," BioRes. 10(1), 877-886.AbstractArticlePDF

    Despite increasing demand for dissolving pulps from raw material, production costs remain quite high compared to regular paper pulp. Research literature to date has focused on improving performance and quality but has not simultaneously explored how to improve yield, which typically falls below 35%. Dissolving pulp from bamboo, as a widely available, high-quality raw material, was investigated with dilute acetic acid pre-hydrolysis before cooking and cold caustic extraction prior to bleaching. It was found that dilute acetic acid in the pre-hydrolysis stage could speed up the degradation of hemicellulose in bamboo and improve the diffusion of the cooking liquor in bamboo fiber compared with hot-water treatment. The dissolving pulp from bamboo was produced with 93% α-cellulose, 90% ISO brightness, 959 mL/g viscosity, 5.23% xylans, and 0.17% ash. The overall yield on the basis of raw material was 37%, which was higher than other documented processes using other agents in pre-hydrolysis.

  • Researchpp 887-897Zhang, A., Liu, C., Xie, J., and Sun, R. (2015). "Homogeneous derivatization of sugarcane bagasse with myristyl chloride at room temperature to prepare bio-based oil absorbents," BioRes. 10(1), 887-897.AbstractArticlePDF

    Homogeneous myristoylation of sugarcane bagasse (SCB) was investigated at room temperature in dimethyl sulfoxide/N-methylimidazole (DMSO/NMI) without any additional catalysts. The effects of reaction time and the dosage of myristyl chloride on the extent of myristoylation were studied. The weight percent gain (WPG) of the modified SCB was 10.7 to 133.2%. The role of NMI as solvent, base, and catalyst at room temperature was proposed. FT-IR and solid-state CP/MAS 13C-NMR analyses provided evidence of myristoylation. The reactions of carbohydrate and lignin fractions were both confirmed. Solid-state CP/MAS 13C-NMR also implied the reaction of three hydroxyl groups at C-2, C-3, and C-6 positions in cellulose. The modified SCB could easily absorb oil with the capacity of 1.57 to 3.76 g/g for engine oil and 1.72 to 3.55 g/g for vacuum pump oil. The enhanced oil capacities exhibited similar trends in terms of WPG with increased reaction parameters. This modified SCB can be used as a potential oil absorbent.

  • Researchpp 898-911Rodriguez-Chiang, L. M., and Dahl, O. P. (2015). "Effect of inoculum to substrate ratio on the methane potential of microcrystalline cellulose production wastewater," BioRes. 10(1), 898-911.AbstractArticlePDF

    The methane potential and influence of the inoculum to substrate ratio of wastewater originating from the production of microcrystalline cellulose (MCC) were studied. Laboratory experiments were carried out in a continuously stirred batch multi-reactor at mesophilic temperature (37 °C). Inoculum to substrate ratios (ISRs) of 2.0, 1.0, 0.8, and 0.5 based on volatile solids (VS) were evaluated. The results demonstrate the suitability of MCC wastewater at ISRs of 2.0, 1.0, and 0.8 with ultimate methane potentials of 333, 297, and 325 mL CH4 per gram of volatile solids added, respectively, which correspond to anaerobic degradabilities of 91.4, 81.7, and 89.3%, respectively, compared to the theoretical potential. The inoculum to substrate ratio of 2.0 provided a faster methane production rate and a kinetic constant of 0.24 d-1, reaching its ultimate yield at day 8 of incubation. The lowest ISR of 0.5 showed the occurrence of process inhibition due to accumulation of acids. Energy estimation suggests that considering the volume and VS of wastewater produced in a MCC mill, a total energy amount of 44,105 GJ/year can be produced, which can be used to replace 29.4% of the natural gas demand.

  • Researchpp 912-921Yoon, K., Takahashi, S., Nge, T. T., Karlsson, O., Nakagawaizumi, A., Ohi, H., Uraki, Y., Yamada, T. (2015). "Thermal melting of lignin derivatives prepared from dried black liquor powder of softwood soda-AQ cooking and polyethylene glycol," BioRes. 10(1), 912-921.AbstractArticlePDF

    Softwood lignin prepared by soda-anthraquinone (AQ) cooking does not have thermal melting characteristics. To improve the properties of softwood soda-AQ lignin, we have invented a new method of lignin modification using dried black liquor powder by a spray dryer system and polyethylene glycol (PEG). In this process, black liquor powder was directly treated with PEG under alkaline conditions to produce PEG-modified lignin (alkaline PEG treatment). Dried black liquor powder prepared by a spray dryer was dissolved into PEG and heated at either 120 or 160 °C at atmospheric pressure. The modified lignin (alkaline PEG-treated lignin) was precipitated with acid and recovered by filtration. The alkaline PEG-treated lignin showed adequate thermal melting characteristics. The treatment temperature and the molecular weights of PEG considerably affected the thermal properties of the alkaline PEG-treated lignin. There was an addition reaction of the PEG to the lignin hydroxyl group at the alpha- (a-) carbon. However, in the acid precipitation step, if the mixture was allowed to set unfiltered for a long time, the PEG bonded with the lignin was hydrolyzed, which yielded the original soda-AQ lignin and PEG polymer.

  • Researchpp 922-931Liu, J., Yang, R., and Yang, F. (2015). "Effect of the starch source on the performance of cationic starches having similar degree of substitution for papermaking using deinked pulp," BioRes. 10(1), 922-931.AbstractArticlePDF

    Cationic waxy corn starch was prepared from waxy corn starch with 2,3-epoxypropyl trimethyl ammonium chloride (ETMAC) as a cationic etherifying reagent. Its structure was identified by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray powder diffraction (XRD). The results showed that quaternary ammonium groups were introduced successfully into the waxy corn starch, and the cationic reaction occurred on the surface of the starch granules. Cationic waxy corn starch was then applied into deinked pulp as a paper reinforcer, and the result was compared with that of cationic tapioca starch and cationic maize starch. In general, the physical strengths of the paper were improved significantly with an increasing dosage of cationic starches. Cationic waxy corn starch was superior in terms of enhancing the physical properties of paper. In addition, with the use of cationic waxy corn starch, anionic trash in the slurry could be better removed.

  • Researchpp 932-942Adam, M. A., Sulaiman, A., Said, C. M. S., Som, A. M., and Tabatabaei, M. (2015). "Enhanced rigidity of natural polymer composite developed from oil palm decanter cake," BioRes. 10(1), 932-942.AbstractArticlePDF

    A natural polymer composite (NPC) was developed from a palm decanter cake (OPDC), and its properties were determined. Oil palm decanter cake natural polymer composite (OPDC-NPC) samples were produced at different ratios of polypropylene (PP) and OPDC before being subjected to flexural, tensile, and water absorption tests. The results showed that by increasing the OPDC content from 5 to 15%, the rigidity as represented by the flexural strength and tensile strength increased from 29 to 43 MPa and 12 to 21 MPa, respectively. However, the flexural modulus decreased from 2230 to 1365 MPa and the water absorption rate increased from 0.16 to 0.44% because of the hydrophilic nature of the OPDC material. The rigidity of OPDC-NPC can thus be improved by increasing the OPDC content from 5 to 15%.

  • Researchpp 943-955Luo, T., Long, Y., Li, J., Meng, X., Mei, Z., Long, E., and Dai, B. (2015). "Performance of a novel downward plug-flow anaerobic digester for methane production from chopped straw," BioRes. 10(1), 943-955.AbstractArticlePDF

    In China, there is an urgent need for an efficient anaerobic digester to sustainably treat rice straw. In this study, a downward plug-flow anaerobic digester (DPAD) was designed in which the total working core is separated into three sections: an upper liquid zone, a lower liquid zone, and a solid-state bed (SSB) in the middle. A solid/liquid separation mechanism was designed to recirculate liquor and the discharged solid residue after complete digestion. The 70-L DPAD was run indoors for 100 d, time in which chopped rice straw (30 to 50 mm in length) was fed every 20 d. The digestion performance and biogas production were analysed to assess the feasibility for practice application. The results showed that the DPAD can control scum formation and offers a methane yield of 162.60 L/kg volatile solids, 21.1% higher than that of the control test. It was also found that straw was continuously and efficiently digested by the DPAD in 3 experimental stages. Methane production rates increased by 76.30%, 57.37%, and 13.33% on the second day compared to the first day, respectively, and then, all decreased as the substrate was gradually exhausted. Based on the results, it is clear that the DPAD is a promising solution for chopped straw digestion.

  • Researchpp 956-969Starr, T., Harper, D. P., and Rials, T. G. (2015). "The effects of electron beam irradiation dose on the mechanical performance of red maple (Acer rubrum)," BioRes. 10(1), 956-969.AbstractArticlePDF

    To understand how electron beam irradiation affects wood physically and chemically, irradiated maple beams (Acer rubrum) and veneers were examined using three-point bend tests, dynamic mechanical analysis (DMA), and NIR- and FTIR- spectroscopy. The MOR from the bending tests revealed a significant decline in the red maple’s strength after a dose of 80 kGy. DMA results showed evidence of crosslinking of the amorphous content of the wood at low doses, followed by degradation at higher doses, with the change in response occurring around 80 kGy. Infrared spectroscopy revealed that the components of wood that were most impacted were the phenolic hydroxyl structures of lignin and cellulose hydroxyls, with the greatest effects being seen after 80 kGy.

  • Researchpp 970-985Vek, V., Oven, P., Poljanšek, I., and Ters, T. (2015). "Contribution to understanding the occurrence of extractives in red heart of beech," BioRes. 10(1), 970-985.AbstractArticlePDF

    Common beech (Fagus sylvatica) is one of the deciduous tree species characterized by the formation of a discolored red heart in the central part of the stem. The aim of this work was to review data in existing literature and to present original results on the extractives present in sapwood and the red heart of beech. Samples of sapwood and red heart were taken from freshly felled beech trees and extracted with a speed extractor. The content of lipophilic and hydrophilic extractives was determined gravimetrically and further evaluated by gas chromatography. The beech wood contained, on average, 1.04% lipophilic and 3.71% hydrophilic extractives. Even though the gravimetrically determined content of lipophilic extractives was comparable in the sapwood and the red heart, saturated fatty acids, fatty alcohols, and free sterols were dominant in the red heart. Sapwood contained a larger amount of total hydrophilic extractives. Mono- and oligosaccharides, sugar acids and alcohols, carboxylic acids, simple phenols, and flavonoids were identified as the prevailing hydrophilic solubles in sapwood, whereas the concentration of sugar alcohols was higher in the red heart. The composition and character of the extractives in the wood of red-hearted beech should be considered the relevant technological factor.

  • Researchpp 986-1007Khadiran, T., Hussein, M. Z., Zainal, Z., and Rusli, R. (2015). "Textural and chemical properties of activated carbon prepared from tropical peat soil by chemical activation method," BioRes. 10(1), 986-1007.AbstractArticlePDF

    Activated carbon (AC) was produced via phosphoric acid (H3PO4) and zinc chloride (ZnCl2) chemical activation methods at 500 °C for 3 h. Tropical peat soil was used as a carbon precursor. The effects of activating agent concentrations on the microstructure and chemical properties of activated carbon were studied. Activated carbon with a high BET (Brunauer-Emmett-Teller) specific surface area (SBET) and a high total pore volume (Vpore) was produced using a 30% H3PO4 chemical activation method. The SBET and Vpore of the activated carbon at this condition were 1974 m2/g and 1.41 cm3/g, respectively. However, the activated carbon prepared using ZnCl2 activation only had a SBET of 794 m2/g and a Vpore of 0.11 cm3/g. The nitrogen adsorption-desorption isotherms of both activated carbons exhibited a combination of Type I and Type II isotherms, due to the simultaneous presence of micro- and mesopores structures. The microcrystallinity of the activated carbons was characterized using an X-ray diffractometer and a Raman Spectroscopy, respectively. The activated carbon produced using H3PO4 activation had higher crystalline properties than the activated carbon prepared using ZnCl2 activation. Thus, this article demonstrates the potential of tropical peat soil as a precursor of AC production.

  • Researchpp 1008-1023Qin, Z., Chen, H., Gao, Q., Zhang, S., and Li, J. (2015). "Wettability of sanded and aged fast-growing poplar wood surfaces: I. Surface free energy," BioRes. 10(1), 1008-1023.AbstractArticlePDF

    The sanding process influences the surface morphology and chemical components of wood, which are two important factors that influence the surface free energy and wettability of wood. The objective of this study was to investigate the roughness of sanded poplar wood and the effects of sanding and aging on the surface free energy using different methods. The roughness parameter (Ra) decreased as the grit number increased, but no change was evident when the grit number increased from 120 to 240. The contact angle of water on the fresh wood samples decreased as the grit number increased. Fresh wood samples were more easily wetted by water than was the aged wood sample, and the contact angles increased as the surface roughness decreased. The surface free energy of sanded, aged wood obtained by the Zisman method may be unsuitable. For the fresh wood samples, the change of surface free energy and its components were not significantly changed when the grit number was higher than 120; for the aged wood samples, the dispersion component appeared to increase slightly as the grit number decreased. The effect of roughness on the acid/base component, acid component, and base component calculated by the vOCG method was unremarkable. The surface free energy of the wood samples (obtained using the liquid parameters provided by Volpe and Siboni (1997)) can effectively balance the relationship between the acid and base components.

  • Researchpp 1024-1036Li, Y., Yang, X., Chen, M., Tang, L., Chen, Y., Jiang, S., and Zhou, X. (2015). "Influence of atmospheric pressure dielectric barrier discharge plasma treatment on the surface properties of wheat straw," BioRes. 10(1), 1024-1036.AbstractArticlePDF

    The effects of atmospheric pressure dielectric barrier discharge (DBD) plasma on the surface properties of wheat straw were investigated in this work. The surface wettability changes in the wheat straw were determined using contact angle measurements, the surface morphology was observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the chemical characteristics were scanned using X-ray photoelectron spectroscopy (XPS). Moreover, the shear strength was measured using a paper tension meter. The results indicated that after plasma treatment, the urea-formaldehyde (UF) resin had lower instantaneous and equilibrium contact angles on the wheat straw surfaces than the untreated specimens did, which decreased by 34% and 64%, respectively. Obvious etching was observed on the wheat straw surface after plasma treatment. There was an increase in the O/C ratio along with an increase in the C2, C3, and C4 proportions based on the XPS analysis after plasma treatment on wheat straw surface. Moreover, the shear strength between glued surfaces of the wheat straw was greatly improved after plasma treatment, indicating that atmospheric pressure DBD plasma treatment was an effective method for improving the surface properties of wheat straw, which were helpful for UF resin penetration and application of wheat straw.

  • Researchpp 1037-1047Li, Z., Fei, B., and Jiang, Z. (2015). "Effect of steam explosion pretreatment on bamboo for enzymatic hydrolysis and ethanol fermentation," BioRes. 10(1), 1037-1047.AbstractArticlePDF

    Based on the steam explosion pretreatment that has been applied to other types of lignocellulosic biomass, the steam explosion pretreatment of bamboo, along with a study of the chemical compositions and enzymatic hydrolyzability of substrates, was conducted. The results show that steam explosion pretreatment can greatly enhance the cellulose-to-glucose conversion yield after enzymatic hydrolysis, which is sometimes affected by bamboo age and steam explosion conditions. When the steam explosion pretreatment conditions were 2.0 MPa (pressure) and 4 min (time), the cellulose-to-glucose conversion yield of 2-year-old bamboo substrate was 62.5%. However, the cellulose-to-glucose conversion yield of bamboo substrates after direct (without steam explosion pretreatment) sodium chlorite/acetic acid delignification was 93.1%. Fermentation of enzymatic hydrolyzates with Saccharomyces cerevisiae resulted in about 88.1% to 96.2% of the corresponding theoretical ethanol yield after 24 h.

  • Researchpp 1048-1059Lemrini, M. M., Lanouette, R., and Michaud, G. (2015). "Merging interstage fractionation and low consistency advantages during the TMP refining process: Part III - How fibre morphology impacts paper properties," BioRes. 10(1), 1048-1059.AbstractArticlePDF

    Fibre morphology and its evolution during refining and fractionation at low consistency were studied to understand the key relationships between the mechanical properties of paper and those of fibres. A broad analysis is presented on the physical and mechanical properties characterising the intrinsic morphological properties of fibres. The experimental refining process involved a primary stage at high consistency (HC), a fractionation stage with a small aperture basket, a low consistency (LC) refining stage, and a final high consistency refining (HCR) stage. The idea was to benefit from the pulp already being at low consistency following the screening step. Using a higher proportion of low consistency refining (LCR) tended to lower the tensile strength at 100 mL CSF, but some intermediate values did exhibit better responses to refining. Fractionation permits the use of LCR to retain fibre length and to develop additional long fibre bonding. The net gain remains even with energy reduction. It is believed, among other things, that a greater number or greater intensity of fibre-to-bar contacts would help increase internal delamination of the fibre structure.

  • Researchpp 1060-1072Ye, Y., Li, Y., and Fang, F. (2015). "Cost effective isolation of bioactive compounds from a discarded bioresource - Defatted seeds of Camellia oleifera," BioRes. 10(1), 1060-1072.AbstractArticlePDF

    The Camellia oleifera oil industry is the economic mainstay in many high-poverty mountain regions of China, but the defatted seeds are currently discarded, leading to a waste of bioresources. In this work, a cost-effective technique was designed to isolate the flavonoid, saponins, and polysaccharides by ultrasonic-assisted acid-base alternative extraction. The activities of these compounds were evaluated by their DPPH and ABTS radical scavenging abilities in vitro and inflammatory inhibition in mice, and the economic efficiency was assessed. The optimal extraction conditions by response surface design were 1.6% HCl, water/seed ratio 16, extraction time 89 min, and ultrasonic power 310 W. The yields of the flavonoid, saponin, and polysaccharide were, respectively, 1.4 ± 0.2%, 6.7 ± 0.8%, and 22.5 ± 1.7%. The extracts could eliminate DPPH and ABTS radicals and alleviate inflammation with concentration dependence, and showed excellent capacity in the order of flavonoid ≥ saponin > polysaccharides. The residue after extraction was cellulose, with a yield of 63.0 ± 2.4%. The defatted seeds could produce a value of $11.35 per kilogram after production of the four valuable extracts, which would greatly increase the income in these high-poverty areas. This integrated extraction technique provides valuable recycling utilization of a typically discarded bioresource.

  • Researchpp 1073-1084Liu, C., Liang, J.-J., Wu, S.-B., and Deng, Y.-B. (2015). "Effect of chemical structure on pyrolysis behavior of alcell mild acidolysis lignin," BioRes. 10(1), 1073-1084.AbstractArticlePDF

    In this study, two purified mild acidolysis lignins (MAL) extracted from triploid poplar, i.e., Alcell MAL and Alkali MAL, were compared. Some properties, including elemental contents, higher heating value (HHV), functional hydroxyl group compositions, and molecular weights, were tested to characterize the structure of these two MALs. The releasing laws of gases and the distribution of products were also investigated through the use of thermogravimetric Fourier transform infrared (TG-FTIR) and pyrolysis-gas chromatography combined with mass spectrometry (Py-GC/MS). The results showed that both MALs had pyrolytic advantages, largely because of their unique chemical structures. However, although the species of volatiles from Alkali MAL were similar to those from Alcell MAL, the releasing temperature range for Alcell MAL was relatively narrow and the volatiles from it were concentrated. Among the fast pyrolytic products, phenols were the most abundant. The yield of 2,6-dimethoxy-4-(2-propenyl)phenol, which was the dominant product, was 25.66% for Alcell MAL and 20.77% for Alkali MAL, respectively. Overall, pyrolytic products from Alcell MAL were more enriched.

  • Researchpp 1085-1098Li, Y., Jia, H., Ruxianguli, R., Yin, H., and Zhang, Q. (2015). "Extraction of lignin from wheat straw by catalysts in 1,4-butanediol medium under atmospheric pressure," BioRes. 10(1), 1085-1098.AbstractArticlePDF

    Extraction of lignin from lignocellulosic materials in an autoclave using 1,4-butanediol medium has been examined by researchers. However, there has been no research on the extraction of lignin in a 1,4-butanediol medium at atmospheric pressure and no extraction of HBS lignin from wheat straw has been investigated. In this paper, lignin was isolated from wheat straw in 1,4-butanediol media (from 50% to 100%, v/v) that was catalyzed by H2SO4 or NaOH while refluxing under atmospheric pressure. Reaction time, liquid-solid ratio, the volume percentage of 1,4-butanediol, as well as catalysts were optimized to improve the lignin yield. The optimum extraction conditions were: 12-to-1 liquor-to-straw ratio of 80% 1,4-butanediol, 1.67% of H2SO4 or 0.83% of NaOH, and 3 h reaction time. The optimum yield of lignin was found to be 60.64%. Analysis with Fourier transform infrared spectroscopy, gel permeation chromatography, and thermogravimetry showed that the lignin obtained using the NaOH catalyst had fewer unconjugated C=O groups, fewer =C-O-C bonds, lower molecular weight, and was more thermally unstable than lignin obtained using the H2SO4 catalyst.

  • Researchpp 1099-1114Silva, A. C. P., Jorgetto, A. O., Wondracek, M. H. P., Saeki, M. J., Schneider, J. F., Pedrosa, V. A., Martines, M. A. U., and Castro, G. R. (2015). "Characterization of corn (Zea mays) leaf powder and its adsorption properties regarding Cu(II) and Cd(II) from aqueous samples," BioRes. 10(1) 1099-1114.AbstractArticlePDF

    In this study, a green adsorbent made of corn leaf powder was applied in the removal of Cu(II) and Cd(II) from water samples. The material was characterized by Fourier transform infrared (FTIR) spectroscopy, which indicated the existence of amine (1375 and 1249 cm-1) and carboxylic groups (1730 cm-1). Elemental analysis corroborated the results of FTIR, indicating that the substance consisted of 0.63% sulfur and 0.46% nitrogen. The NMR results indicated that thiamine and methionine may be present in the corn leaf substances, which can act in coordination with metal species. Scanning electron microscopy (SEM) indicated the existence of pores of approximately 15 µm in diameter and a homogeneous particle size. Equilibrium adsorption was attained in 5 min, and the obtained data were applied to a pseudo-second-order kinetic model (r2 = 0.999 for Cu(II) and Cd(II)). Selective adsorption of Cu(II) was attained at pH 3.0, and the maximum adsorption capacities were attained at pH 6.0. Adsorption isotherms were adjusted to a modified Langmuir equation and the maximum number of moles adsorbed of Cu(II) and Cd(II) were 0.089 and 0.071 mmol g-1, respectively. The results are superior to many materials currently employed in metal removal from aqueous samples.

  • Researchpp 1115-1126Montón, J., Arriaga, F., Íñiguez-González, G., and Segués, E. (2015). "Warp requirements and yield efficiency in the visual grading of sawn radiata pine timber," BioRes. 10(1), 1115-1126.AbstractArticlePDF

    Three samples of sawn Radiata pine (Pinus radiata D. Don) timber, consisting of 150 pieces with dimensions of 80 mm x 120 mm x 2400 mm, 80 pieces with dimensions of 150 mm x 200 mm x 4500 mm, and 75 pieces with dimensions of 150 mm x 250 mm x 5600 mm, were visually graded according to the Spanish standard UNE 56544 (2011) to analyze the influence of visual grading requirements on both the grading yield and mechanical properties. The resulting percentages of the rejected pieces stood at 19 and 28% for 150 x 200 mm and 150 x 250 mm cross-section pieces, respectively. That percentage increased to 73% for 80 x 120 mm cross-section pieces. The grading yield and mechanical properties were then analyzed to determine the influence of warp defects. Three different criteria for limiting warp defects were considered, reducing the standard specifications. The modulus of elasticity, bending strength, and density were obtained. The results concluded that loosening specified requisites improves the visual grading output in the smallest cross-section, with no significant reduction in the mechanical properties. A proposal for a less rigorous specification of twist defects in the Spanish visual grading standard has been introduced.

  • Researchpp 1127-1136Cosereanu, C., Brenci, L.-M., Zeleniuc, O., and Fotin, A. (2015). "Effect of particle size and geometry on the performance of single-layer and three-layer particleboard made from sunflower seed husks," BioRes. 10(1), 1127-1136.AbstractArticlePDF

    The effects of particle size and geometry on the physical (density, water absorption, and thickness swelling), thermal, and mechanical (modulus of elasticity, bending strength, internal bond strength, and screw holding strength) properties of single-layer and three-layer particleboards made from sunflower seed husks were investigated. Panels manufactured from particles with various sizes using a urea-formaldehyde adhesive had densities ranging from 535 to 682 kg/m3. The adhesive ratio was at a level of 16% for the single-layer mat configuration; for the three-layer structure, levels of 14% for the core and 16% for the faces were used, based on the weight of particles. The best results occurred in single-layer particleboard made from fine particles, which nearly met the general purpose requirements of the EN 312 Standard. Determination of the thermal conductivity coefficient demonstrated good insulation properties of all panels and their potential use for different structural configurations which are not subjected to strong stresses, suitable for interior design.

  • Researchpp 1137-1148Hodoušek, M., Böhm, M., Lemaster, R. L., Bureš, M., Beránková, J., and Cvach, J. (2015). "Air permeation rate of oriented strand boards (OSB/3 and OSB/4)," BioRes. 10(1), 1137-1148.AbstractArticlePDF

    Measurements of air permeation rate were taken according to EN 12114 for OSB boards, which were manufactured ​​for this purpose in accordance with the requirements of EN 300 by a commercial manufacturer. The study measured the air permeation rate of samples and evaluated the influence of selected parameters on the resulting values. The effects of these factors on the rate of air permeation were specified, showing the particular influences of board thickness (12 mm and 18 mm) and type (OSB/3 and OSB/4). The dependence of the measured values ​​of air permeation rate on the pressure difference was described using linear equations within a regression analysis. The group of OSB/3 samples exhibited a lower resistance to air permeation than OSB/4 (about 61% for both thicknesses). In addition, in both groups, 18 mm samples showed a higher resistance to air permeation than samples with a thickness of 12 mm (OSB/3 by about 40% and OSB/4 by about 41%).

  • Researchpp 1149-1161Xiong, F., Zhou, L., Qian, L., and Liu, S. (2015). "Effects of pretreatment methods using various 1,4-dioxane concentrations on the performance of lignocellulosic films of Eucalyptus citriodora," BioRes. 10(1), 1149-1161.AbstractArticlePDF

    In order to obtain a material that exhibits a better tensile strength, UV absorption, and transparency, lignocellulose of eucalyptus was dissolved and subsequently regenerated in ionic liquid (IL) following treatment with different pretreatment conditions. The effect of 1,4-dioxane extraction concentration was evaluated by comparing the chemical, thermal, mechanical, and optical performance of the obtained films. The results indicated that lignocellulose could be dissolved using the IL, with the regenerated film demonstrating obvious signs of phase separation. Increasing the 1,4-dioxane extraction concentration brought about an increase in the degree of crystallization, tensile stress, and ultraviolet-visible light transmittance of films. However, the lignin content and peak temperature of main decomposition for the films decreased. Compared to cellulose film, lignocellulose film showed excellent UV absorption properties due to the presence of lignin. F-90 possessed of a better tensile strength, UV absorption, and transparency. This work demonstrated the possibility that a biodegradable green functional film can be prepared.

  • Researchpp 1162-1173Ji, L., Yu, H., Liu, Z., Jiang, J., and Sun, D. (2015). "Enhanced ethanol production with mixed lignocellulosic substrates from commercial furfural and cassava residues," BioRes. 10(1), 1162-1173.AbstractArticlePDF

    Simultaneous saccharification and fermentation (SSF) is an attractive process configuration for bio-ethanol production. Further reductions in process cost of SSF are expected with the use of waste agricultural or industrial materials as feedstock. In the current study, two industrial lignocellulosic wastes, cassava residues (CR) and furfural residues (FR), were combined during SSF for ethanol production due to their value-added applications and positive environmental impacts. After CR were liquefied and saccharified, saccharification liquid was added to SSF of FR. The effect of substrate fractions was investigated in terms of ethanol yield, byproduct concentration and the number of yeast cells. Besides, a natural surfactant, Gleditsia saponin, was added to investigate the effect of FR lignin on SSF with 20% substrate concentration. The results showed that increasing the ratio of CR/FR improved the ethanol yield and that the ethanol yield was also increased gradually by increasing the substrate concentration from 6% to 12%. A high ethanol concentration of 36.0 g/L was obtained under the condition of CR:FR = 2:1 with 12% substrate concentration, reaching 71.1% of the theoretical yield. However, Gleditsia saponin did not affect the ethanol yield, indicating the insignificant effect of lignin in SSF with low lignin content in the reaction system.

  • Researchpp 1174-1185Kim, S. Y., Lee, J. Y., Kim, C. H., Lim, G. B., Park, J. H., and Kim, E. H. (2015). "Surface modifications of organic fillers to improve the strength of paperboard," BioRes. 10(1), 1174-1185.AbstractArticlePDF

    In a previous study the authors determined that non-woody materials including brewers’ grain (BG) and oil palm frond (OPF) could be alternatives to wood powder as organic fillers. However, they have the disadvantage of deteriorating the strength of paperboard. If the strength of paperboard could be improved, then one would expect more production cost reductions and bulk improvements by increasing the addition of organic fillers. In this study, surface modification of organic fillers was used as a method to improve paperboard strength. The goal was to find the most effective condition for surface modifications. Surface modifications of BG and OPF fillers were carried out using cationic and oxidized starches, and the strengths and reductions in the drying energies of the sheets were measured. The zeta potentials of the modified organic fillers showed that the surface modifications were performed properly. Surface modification with starches improved the bulk and strength of the sheets simultaneously, and modification with the addition of a large amount of cationic starch was more effective in improving the strengths and the reductions in drying energies of the sheets than using cationic and oxidized starches together.

  • Researchpp 1186-1197Lestiani, R., Batchelor, W., and Banham, P. (2015). "Dynamic optical measurement of lint accumulation during offset printing," BioRes. 10(1), 1186-1197.AbstractArticlePDF

    Linting occurs when small particles are removed from the paper surface by the splitting of the tacky ink film. Excessive linting reduces printing quality and can affect the pressroom efficiency. An improved method, using video camera technology, has been utilized to measure the dynamics of linting during the printing process. This technology makes it feasible to estimate the removal of lint particles from the paper and from the blanket surfaces. This article presents the latest development of the lint camera system and its applications under different press conditions, including ink color. The lint measurements obtained by the camera system were compared with the established measurement methods (blanket tape pull and blanket wash). The main result from this study indicates some similarities in the lint area distribution measured by the camera system and the blanket tape pull. The differences in the lint area distribution from the filtered sample at small particle sizes is likely due to disaggregation of the agglomerated lint particles during the washing and filtering, and as a result, of more small particles being measured from the tape pulls.

  • Researchpp 1198-1212Liu, Y., Hu, J., Gao, J., Guo, H., Chen, Y., Cheng, Q., and Via, B. K. (2015). "Wood veneer dyeing enhancement by ultrasonic-assisted treatment," BioRes. 10(1), 1198-1212.AbstractArticlePDF

    To extend the potential application of ultrasonic treatment in dyeing low-quality wood to improve decorative value, wood veneers were dyed with an ultrasonic assisted dyeing system. The effects of ultrasonic power, dye concentration, dyeing time, and temperature of ultrasonic-assisted treatment on dye-uptake, chromatic value, crystallinity, thermal stability, chemical structure, and microstructure for dyed wood veneer were investigated. The dye-uptake, chromatic value, and dyeing rate were improved by ultrasonic-assisted treatment. The effect was strengthened with an increase in ultrasonic power, dye concentration, and dyeing time and temperature. After ultrasonic treatment, the dyed wood properties such as lignin degradation, crystallization and thermal stability decreased slightly, and part of the wood microstructure such as the pit membrane and parenchyma cells was mechanically damaged. Ultrasonic-assisted treatment enhanced the permeability of wood by creating new fluid channels and sorption sites, and it is believed to be an energy-efficient and environmental wood dyeing technique.

  • Researchpp 1213-1223Low, J. C., Halis, R., Shah, U. K. M., Paridah, T., Abood, F., Tuhaila, T., Idris, M. D., Lanika, L., and Razali, N. (2015). "Enhancing enzymatic digestibility of alkaline pretreated banana pseudostem for sugar production," BioRes. 10(1), 1213-1223.AbstractArticlePDF

    This study compares the efficacy of a soaking pretreatment with an alkaline solution for banana pseudostem prior to enzymatic hydrolysis. Banana pseudostem was pretreated by soaking in sodium hydroxide solutions at various concentrations and durations. The pretreatment more than doubled delignification but retained 82.09% of the holocellulose content and 73.74% of the cellulose content. The enzymatic (Trichoderma reesei) digestibility of pretreated banana pseudostem was found to have been enhanced by 44.41% as compared to initial biomass. This was evidenced by higher enzymatic activities (endoglucanase, exoglucanase, and β-glucosidase) on the treated sample. Meanwhile, glucose yield showed a proportional relationship with incubation time and enzyme loading throughout the hydrolysis process.

  • Researchpp 1224-1244Andersch, A., Montague, I., Buehlmann, U., and Wiedenbeck, J. K. (2015). "U. S. hardwood sawmill log procurement practices," BioRes. 10(1), 1224-1244.AbstractArticlePDF

    U.S. hardwood sawmill log procurement practices are evolving because of the recent economic recession, market and supply chain shifts, and changing landowner objectives, among other factors. The objective of this study was to characterize the log procurement practices of hardwood sawmills and to characterize the role that log brokers play in supplying the sawmill industry with raw material. To meet this objective, a mail survey on hardwood log procurement practices in the U.S. hardwood sawmill industry was conducted. Survey respondents highlighted several factors that had major effects on their businesses, including “Increasing fuel and trucking cost,” “High logging cost,” “Unpredictable log supply,” “Log shortages,” “Logger shortages,” and “Low log quality,” among others. Results showed that large sawmills tend to rely more on gatewood from loggers and stumpage harvested by company contract loggers than do small- and medium-sized sawmills. This study failed to find an increase in the role of log brokers as an intermediary between landowners and hardwood sawmills during the last decade. Moreover, sawmills indicated only a limited demand for log broker services, with log delivery and the procurement of specialty logs identified as being the most highly demanded broker services.

  • Researchpp 1245-1259Li, W., Zhang, M., Du, Z., Ma, Q., Jameel, H., and Chang, H.-m. (2015). "Photocatalytic degradation of lignin model compounds and kraft pine lignin by CdS/TiO2 under visible light irradiation," BioRes. 10(1), 1245-1259.AbstractArticlePDF

    Cadium sulfide/titanium dioxide (CdS/TiO2) catalyst was prepared by two different methods: microemulsion-mediated solvothermal hydrolyzation (CdS/TiO2 (SH)) and in-situ sulfurization under supercritical conditions (CdS/TiO2 (SS)). The photocatalysts were characterized by nitrogen adsorption-desorption, X-ray diffraction, X-ray photoelectron spectra, UV-Vis absorption spectra, and PL spectra. Photodegradationreactions of three monomeric and one dimeric lignin model compounds, and kraft pine lignin (Indulin AT) were carried out at room temperature in a weak alkaline aqueous system by visible light irradiation with air bubbling. Quantitative results showed that these lignin model compounds and kraft lignin were effectively degraded. While both phenolic and non-phenolic lignin units are reactive, the phenolic units appeared to react faster and preferentially reacted.

  • Researchpp 1260-1270Chang, H.-T., Yeh, T.-F., Hsu, F.-L., Kuo-Huang, L.-L., Lee, C.-M., Huang, Y.-S., and Chang, S.-T. (2015). "Profiling the chemical composition and growth strain of giant bamboo (Dendrocalamus giganteus Munro)," BioRes. 10(1), 1260-1270.AbstractArticlePDF

    The chemical composition of the wax layer and green epidermis at the surface of giant bamboo (Dendrocalamus giganteus Munro) culms were conveniently analyzed through the diffuse reflectance infrared Fourier transform (DRIFT) with Si-Carb sampling technique. Results from the radial lignin content profiling of giant bamboo showed that the lignin content in the middle layer was lower than the layers either from the inner or outer culms. As for the longitudinal depth profiling, the lignin contents of bamboo culms increased gradually from the top toward base portion. The distribution of growth strains in the radial direction of giant bamboo culm was investigated by the kerf method with strain gauges. The longitudinal tensile strains in various positions of giant bamboo culm were found to decrease in the order of the middle layer, the outer layer, and the inner layer. The tensile strains of different layers in the radial direction of giant bamboo culm correlate with their lignin content. The highest tensile strain on the middle layer of the bamboo culm was associated with the lowest lignin content. These results provided experimental evidence in the relationship between longitudinal tensile strain and lignin content of bamboo culm.

  • Researchpp 1271-1284Wang, P., Zhao, Z.-D., Wang, Z.-D., Chen, S.-X., and Fan, G.-R. (2015). "Hydrothermal synthesis of mesoporous nanocrystalline tetragonal ZrO2 using dehydroabietyltrimethyl ammonium bromine," BioRes. 10(1), 1271-1284.AbstractArticlePDF

    Mesoporous nanocrystalline tetragonal zirconias were successfully synthesized through a hydrothermal method using a novel bioresource-derived quaternary ammonium salt, dehydroabietyltrimethyl ammonium bromine (DTAB), as a templating agent. The templating agent provides a surface area (242.02 m2/g), high pore volume (0.53 cm3/g), and large average pore diameter (7.65 nm), which suggests that DTAB is a good candidate for mesostructure synthesis. The hydrothermal treatments give the materials improved thermal stabilities because of the generation of tetragonal nanocrystallites that are more stable than the bulk amorphous ones in the hydrothermal process. However, because of the absence of stabilizers, the sizes of the crystallites of the as-synthesized sample increase gradually with increasing calcination temperature. As the crystalline size of the sample rises to 25 nm, the nanocrystallites become too large to integrate well together, causing the well-organized mesostructure to collapse.

  • Researchpp 1285-1292Wang, B., Lv, Y., Li, J., and Qian, L. (2015). "Separate treatment of long fibres and fines of spruce CTMP in laccase mediator system treatment," BioRes. 10(1), 1285-1292.AbstractArticlePDF

    Spruce chemithermomechanical pulp was treated with a laccase mediator system (LMS) and alkaline H2O2, and the whiteness and dye removal index of the long fibres fraction and fines fraction were compared. The long fibres fraction and fines fraction were treated separately with a LMS, and their whitenesses and strengths were tested. The results indicated that the lignin and extractives contents of the fines fraction were higher than that of the long fibres. Because of the strong adsorption capacity and higher reactive efficiency, the optimal laccase dosage of the fines fraction was lower than that of the long fibres. In the process of treatment using a LMS and alkaline H2O2, at the same laccase dosage, separate treatment of the long fibres fraction and fines fraction could improve pulp whiteness and pulp strength.

  • Researchpp 1293-1303Kureli, I., and Doganay, S. (2015). "The effects of surface roughness, adhesive type, and veneer species on pull-off strength of laminated medium density fibreboard," BioRes. 10(1), 1293-1303.AbstractArticlePDF

    This study investigated the pull off strengths of various laminated medium density fiberboards (MDFs). The surface roughness of the MDF, adhesive type, and veneer type were all studied. Polyvinylacetate (PVAc), urea formaldehyde (UF), and gluten were used as the adhesives for beech, pine, and oak veneers. There were a total of 216 experimental specimens that were tested according to the principles specified in the TS 5339 (1987) standard. According to the statistical analyses of the data obtained from the tests, surface roughness, veneer species, and adhesive type all affected the pull-off strength of the laminated MDF. The highest pull-off strength (2.88 N/mm2) was obtained with the MDF unsanded with 120-grit abrasive and laminated with PVAc adhesive and pine veneer. The lowest pull-off strength (1.60 N/mm2) was obtained with the unsanded MDF laminated with PVAc adhesive and oak veneer.

  • Researchpp 1304-1317Zhang, R., Xu, K., and Ye, K. (2015). "Concentration and distribution of nuclei and plastids in xylem cells in Cunninghamia lanceolata and Aquilaria sinensis," BioRes. 10(1), 1304-1317.AbstractArticlePDF

    After programmed cell death (PCD), heartwood formation, storage, and processing, wood DNA degradation occurs to varying degrees. The concentration and distribution of nuclei and plastids in xylem cells of Cunninghamia lanceolata and Aquilaria sinensis, treated under different conditions of processing and storing, were studied by analyzing the distribution frequency, area, and signal intensity, in specimens that had been stained with aceto-carmine, DAPI, and I2-KI. Most of the nuclei and plastids were present in the ray cells, and a small quantity of nuclei and plastids were present in the axial parenchyma cells. There was an indication that the concentration of the remaining nuclei and plastids in the xylem cells was mainly affected by the xylem heartwood formation, storage time, and temperature. The nuclei and plastids content of the sapwood was greater than that of the heartwood. However, the nuclei and plastids content of the fresh wood was greater than that of the processed and stored wood. An estimation of the quantity of nuclei and plastids using staining methods could provide a direct basis for the appropriate selection of a procedure for DNA extraction.

  • Researchpp 1318-1329Jiang, L.-Q., Fang, Z., Zhao, Z.-L., He, F., and Li, H.-B. (2015). "2,3-butanediol and acetoin production from enzymatic hydrolysate of ionic liquid-pretreated cellulose by Paenibacillus polymyxa," BioRes. 10(1), 1318-1329.AbstractArticlePDF

    A safe microorganism (class 1), Paenibacillus polymyxa, was used for 2,3-butanediol and acetoin production, which could make the fermentation process cheaper and less complex. It showed a broad substrate spectrum, such as mannose, galactose, cellobiose, glycerol, the mixture of glucose and xylose, and the mixture of glucose and cellobiose. In addition, the strain can utilize highly concentrated glucose that was obtained by enzymatic hydrolysis of ionic liquid-pretreated cellulose. With a 15% initial cellulose consistency, the final glucose concentration was 109.5 g/L with 65.7% glucose yield. Without any treatment, the hydrolysate was successfully used to produce 2,3-butanediol and acetoin with a yield of 81.7% and a productivity of 0.7 g/(L·h) by Paenibacillus polymyxa. Higher concentration and higher productivity with relatively high yield, compared with previous works by acid hydrolysis, of 2,3-butanediol and acetoin were achieved. All these novel improvements offer significant opportunities to further decrease the cost of large-scale 2,3-butanediol and acetoin production.

  • Researchpp 1330-1345Shi, Y., Zhang, L., and Zhao, M. (2015). "Effect of biochar application on the efficacy of the nitrification inhibitor dicyandiamide in soils," BioRes. 10(1), 1330-1345.AbstractArticlePDF

    A series of laboratory incubation experiments was conducted to evaluate the effect of biochar application on the efficacy of the nitrification inhibitor (NI) dicyandiamide (DCD) in Cambisol (pH 7.14) and Latosol (pH 4.83). The feedstocks (eucalyptus wood, coconut coir, and rice straw), pyrolysis temperatures (350, 500, and 650 ˚C), and application rates (0.5, 1.0, 2.5, and 5.0% of 200 g soil) were identified as influential factors. The results showed that biochar could significantly reduce the effectiveness of DCD on nitrification inhibition. Biochar produced from eucalyptus wood with a large surface area (426.4 m2 g−1) had the strongest ability to reduce the inhibitory effect of DCD in nearly neutral Cambisol, while biochar from rice straw with a high pH had the greatest influence on acidic Latosol. Increasing pyrolysis temperature and application rates can strengthen the ability of biochar to reduce the inhibitory effect of DCD. Generally, the decrease of the DCD nitrification inhibitory effect on nearly neutral soil was controlled by the surface area of the applied biochar; meanwhile, the rise of soil pH caused by biochar application was also an important influencing factor in acid soil.

  • Researchpp 1346-1356Fu, J., Yang, F., Mo, J., Zhuang, J., and Lu, X. (2015). "Catalytic decomposition of glucose to levulinic acid by synergy of organic Lewis acid and Brønsted acid in water," BioRes. 10(1), 1346-1356.AbstractArticlePDF

    Four organic Lewis acids, samarium(III), aluminum(III), yttrium(III), and indium(III) trifluoromethanesulfonates were combined with four organic Brønsted acids, benzenesulfonic, toluene-p-sulfonic, trichloroacetic, and oxalic acids to synergistically catalyze the decomposition of glucose to produce levulinic acid (LA). The combination of aluminum trifluoro-methanesulfonate (Al(CF3SO3)3) and oxalic acid (H2C2O4) exhibited a strong synergic activity for the decomposition of glucose to LA. The effects of the mole fraction of Al(CF3SO3)3 in the Al(CF3SO3)3-H2C2O4 system on the decompositions of glucose, fructose, and 5-hydroxymethylfurfural (5-HMF) were investigated. The mixed-acid system showed the strongest synergic catalytic activity for glucose, fructose, and 5-HMF decompositions at the Al(CF3SO3)3 mole fraction of 0.33. The effect of temperature on the decomposition of glucose in the Al(CF3SO3)3-H2C2O4 system was also investigated. Based on the results obtained in this contribution and previous work, synergy in catalytic systems was demonstrated.

  • Researchpp 1357-1365Chen, S., Zhang, X., Zhu, H., and Cao, X. (2015). "Optimization synthesis conditions and characterization of oil biosorbent: Sugarcane bagasse cellulose-graft-polystearylmethacrylate copolymer," BioRes. 10(1), 1357-1365.AbstractArticlePDF

    In this research, sugarcane bagasse cellulose, an abundant non-wood plant fibrous raw material from Guangxi, was the substrate, stearyl methacrylate was the monomer, and ammonium persulfate was the initiator used to prepare an economical environmental oil biosorbent named sugarcane bagasse cellulose-graft-polystearylmethacrylate (SBC-g-PSMA), which can be obtained through homogeneous graft copolymerization in the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). Confirmation of successful synthesis was rendered using various analytical tools, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-Ray Diffraction (XRD). Furthermore, the effects of various reaction parameters on the sorption capacity were all evaluated. Optimum conditions for the synthesis process were obtained as follows: the mass ratio of the monomer to sugarcane bagasse cellulose was 4:1, and the initiator to sugarcane bagasse cellulose ratio was 1:10, with a reaction time of 2 h. Under the optimum conditions, the maximum sorption capacities of the SBC-g-PSMA for 0.2 wt% hydrocarbon (benzene, kerosene, and diesel) were 10.24 g/g, 9.76 g/g, and 9.74 g/g, respectively. The SBC-g-PSMA was light and hydrophobic. It is a selective oil absorption material, so it holds promise to be applied in the treatment of low concentration oily wastewater.

  • Researchpp 1366-1377Chang, F., Kwon, J. H., Kim, N. H., Endo, T., and Lee, S. H. (2015). "Effect of hot-compressed water treatment of bamboo fiber on the properties of polypropylene/bamboo fiber composite," BioRes. 10(1), 1366-1377.AbstractArticlePDF

    A water-soluble fraction of bamboo ranging from 9.2 to 23.5 wt% was obtained by hot-compressed water (HCW) treatment as the temperature increased from 140 to 180 °C. Both untreated and HCW-treated bamboo fibers (BF) were then compounded with polypropylene (PP), either with or without the addition of 5 phr maleic anhydride-grafted PP (MAPP), to net a total BF content of 50, 30, or 10%. It was found that both the HCW treatment and the MAPP addition effectively improved the tensile properties of the composite. Furthermore, the re-compounding of 70/30 and 90/10 composites from a 50/50 master batch proved to be more effective in improving the tensile properties than the direct compounding of PP and non- or HCW-treated BF to the same composition.

  • Researchpp 1378-1393Guan, Y., Qi, X.-M., Zhang, B., Chen, G.-G., Peng, F., and Sun, R. C. (2015). "Physically crosslinked composite hydrogels of hemicelluloses with poly(vinyl alcohol phosphate) and chitin nanowhiskers," BioRes. 10(1), 1378-1393.AbstractArticlePDF

    Hydrogels have been widely studied as tissue engineering scaffolds due to their swelling capabilities in water and other physical properties. In this study, phosphatized PVAs of varying degrees were prepared by esterification of phosphoric acid, and a freeze-thaw technique was introduced to fabricate hydrogels from hemicelluloses, poly(vinyl alcohol phosphate) (P-PVA), and chitin nanowhiskers. The obtained hydrogels were characterized by Fourier transform infrared (FT-IR) spectrometry, scanning electron microscopy (SEM), X-ray diffraction (XRD), and CP/MAS 13C nuclear magnetic resonance; their swelling properties and compressive strength were also determined. The repeated freeze-thaw cycles induced physically crosslinked chain packing among the three polymers by hydrogen bonds. The results showed that the hydrogels possessed higher swelling ratio and mechanical strength when the PVA was phosphatized by phosphoric acid and urea and more hydroxyl groups were introduced into the polymer matrices. This suggested that hydrogels with good mechanical properties were prepared successfully by the freeze-thaw technique.

  • Researchpp 1394-1407Islam, M. S., Ahmad, M. B., Hasan, M., Aziz, S. A., Jawaid, M., Haafiz, M. K. M., and Zakaria, S. A. H. (2015). "Natural fiber-reinforced hybrid polymer nanocomposites: Effect of fiber mixing and nanoclay on physical, mechanical, and biodegradable properties," BioRes. 10(1), 1394-1407.AbstractArticlePDF

    Combining two kinds of fibers is a potential way to improve the essential properties of natural fiber-reinforced hybrid polymer composites. Biocomposites produced from natural resources are experiencing an increase in interest due to their high demand in the market for manufacturing, in addition to environmental and sustainability issues. In this study, natural fiber-reinforced hybrid polymer nanocomposites were prepared from coir fiber, wood fiber, polypropylene, and montmorillonite nanoclay using a hot press technique. The effects of fiber mixing and montmorillonite on their physico-mechanical and biodegradable properties were subsequently investigated. Before being used, both the wood and the coir fibers were alkali-treated to reduce their hydrophilicity. The mechanical properties of the fabricated composites were measured using a universal tensile testing machine and found to be enhanced after fiber mixing and nanoclay incorporation. Fourier transform infrared spectra indicated that the characteristic peaks of the composites shifted after fiber mixing. A new peak around 470 cm-1 was observed in the case of the nanocomposites, which confirmed the interaction between the fiber, polymer, and montmorillonite (MMT). Scanning electron microscopic analysis revealed that MMT strongly improved the adhesion and compatibility between the fiber and polymer matrix. The combining of fibers improved the biodegradability and water absorption properties, while MMT addition had the reverse effect on the same properties of the composites.

  • Researchpp 1408-1423Šurina, I., Jablonský, M., Ház, A., Sladková, A., Briškárová, A., Kačík, F., and Šima, J. (2015). "Characterization of non-wood lignin precipitated with sulphuric acid of various concentrations," BioRes. 10(1), 1408-1423.AbstractArticlePDF

    Lignin is an attractive, renewable raw material provided by all types of agricultural and silvicultural vegetation. The precipitation of lignin fractions through acidification of the black liquor was performed and the products characterized for the following parameters: C, H, N, and S elemental composition; zeta potential; electrophoretic mobility; heating value; molecular weight; content of non-conjugated, conjugated, and total phenolic hydroxyl groups; and total yield of oxidation products. Lignin was isolated from black liquor by adding sulphuric acid at four levels of concentration (5, 25, 50, and 72 wt%) and subsequently adjusting the pH to 5. A comparison study of the physico-chemical and surface properties was also performed. The acid concentration influenced the yield of precipitated lignin and had an effect on the properties of precipitated lignin and the content of non-conjugated, conjugated, and total amount of phenolic hydroxyl groups. However, the concentration of acid had no relevant effect on the heating value, molecular weight, polydispersity, total yield of oxidation products, or the elemental composition of isolated lignin.

  • Researchpp 1424-1433Zaia, U. J., Cortez-Barbosa, J., Morales, E. A. M., Lahr, F. A. R., do Nascimento, M. F., and De Araujo, V. A. (2015). "Production of particleboards with bamboo (Dendrocalamus giganteus) reinforcement," BioRes. 10(1), 1424-1433.AbstractArticlePDF

    The focus of this research was to study the utilization of residues from bamboo (Dendrocalamus giganteus) lamination in the manufacturing of panels for structural purposes. Bamboo particleboards were produced under three conditions: pure boards, reinforced with bamboo laminas, and with treated particles. Castor oil-based polyurethane was the resin binder, in view of using lower toxicity materials. The mechanical tests were performed according to Brazilian Standard (NBR) 14810-3 (2006) and European Standard (EN) 310 (2000). The results were superior to those recommended by these and other standards for internal adhesion resistance, modulus of rupture, and elasticity in static bending, as well as to the results of other studies. Starch treatment was an unnecessary stage. According to the conditions of this process, the studied panels showed a good potential for construction use. Moreover, the bamboo particleboards are an economically viable, environmentally friendly, and sustainable alternative for the use of waste generated during the processing of Dendrocalamus giganteus bamboo species, allied with castor oil-based polyurethane resin. The reinforced particleboard and its production process are being licensed as an Innovation Patent in Brazil, (BR 1020130133919-1-2013).

  • Researchpp 1434-1451Anjum, F., Bukhari, S. A., Siddique, M., Shahid, M., Potgieter, J. H., Jaafar, H. Z. E., Ercisli, S., and Zia-Ul-Haq, M. (2015). "Microwave irradiated copolymerization of xanthan gum with acrylamide for colonic drug delivery," BioRes. 10(1), 1434-1451.AbstractArticlePDF

    Xanthan gum (XG) is a polysaccharide produced by Xanthomonas campestris. The aim of the present study was to modify the xanthan by hydrolysis and grafting with acrylamide through microwave irradiation for different time intervals. Pure xanthan was partially hydrolyzed via enzymatic and chemical treatments followed by optional grafting. Proximate composition analysis, moisture content, and carbohydrate, protein, lipid, and fiber contents were determined. The morphological characteristics, structural composition, functional groups, and heat resistance of the crude, hydrolyzed, and grafted gum were evaluated using SEM, XRD, FTIR spectroscopy, and TGA. Morphological studies revealed that xanthan was broken down into smaller fragments as a result of hydrolysis and became somewhat smoother. Thermal analysis studies indicated a larger heat tolerance in the grafted xanthan relative to that of the native and hydrolyzed gums. Xanthan bound to a triamcinolone drug was evaluated in the context of controlled drug release. Controlled drug release correlated well with the exposure time to microwaves used to graft the gum.

  • Researchpp 1452-1461Pu, G., Zhu, W., Zhou, H., Lei, Q., Zhang, Z., and Liu, J. (2015). "Co-combustion characteristics of inferior coal and biomass blends in an oxygen-enriched atmosphere," BioRes. 10(1), 1452-1461.AbstractArticlePDF

    Combustion characteristics and thermal dynamic characteristics of blends of inferior coal and core plywood under different oxygen-enriched atmospheres were investigated using thermogravimetric (TG) analysis. According to the results, with increasing oxygen concentration, TG and DTG curves tended to move to a lower temperature region. The comprehensive combustion characteristic index SM was first proposed in this work, suggesting that the enriched oxygen concentration can significantly improve the combustion conditions. Apparent activation energies were also put into the calculation and analysis, which showed that the apparent activation energy increases with an increasing oxygen concentration. The factor Fc () was defined for the first time, and it was found that Fc can represent the temperature at which combustion can proceed under the same blend ratio condition.

  • Researchpp 1462-1476Zhang, Y., Liu, Z., Cao, Y., Li, R., and Jing, Y. (2015). "Impact of binder composition on inkjet printing paper," BioRes. 10(1), 1462-1476.AbstractArticlePDF

    This article is focused on the impact of different binder mixtures on the performances of paper surface and printability. The coating properties were studied with the chosen silica pigment, and the binder consisted of vinyl acetate copolymer and polyvinyl alcohol with different ratios, followed by the measurement of smoothness, whiteness, and surface strength. The inkjet image quality was assessed using water-based inks. The print density, dot gain, and line quality were analyzed. The results showed that the surface performance and printability were affected by the composition of the binder. With the decrease of vinyl acetate copolymer and the increase of polyvinyl alcohol, the surface smoothness and strength decreased, and the penetration and diffusion of the ink changed as well. When the binder mixture was used with proper ratio, a larger solid density, smaller dot gain, and higher definition can be achieved, which were better than using either one of them alone.

  • Researchpp 1477-1486Fredriksson, M., Bomark, P., Broman, O., and Grönlund, A. (2015). "Using small diameter logs for cross-laminated timber production," BioRes. 10(1), 1477-1486.AbstractArticlePDF

    Sawing small diameter logs results in lower yield compared to sawing large diameter logs. This is due to geometry; fitting rectangular blocks inside an approximately cylindrical shape is more difficult for small than for large diameters. If small diameter logs were sawn in a way that follows the outer shape, yield would increase. The present study considers whether this can be done by sawing flitches into trapeze shapes. These can be glued together into rectangular products. Cross laminated timber (CLT) products are suitable for this. The study was based on 4,860 softwood logs that where scanned, and the scanning data was used for sawing simulation. The log top diameters ranged from 92 to 434 mm. The volume yield of CLT production using trapeze edging was compared to cant sawing of boards. The trapeze edging and CLT production process improved yield compared to cant sawing by 17.4 percent units, for logs of a top diameter smaller than 185 mm. For all logs, the yield decreased using the trapeze edging method. To conclude, a trapeze edging method shows promise in terms of increasing volume yield for small diameter logs, if boards can be properly taken care of in a CLT production process.

  • Researchpp 1487-1494Yun, H., Tu, D., Li, K., Huang, J., and Ou, L. (2015). "Variation and correlation of heat-treated wood's crystalline structure and impact toughness," BioRes. 10(1), 1487-1494.AbstractArticlePDF

    This study aimed to investigate the changes in the fiber characteristics, relative crystallinity, and impact toughness of heat-treated Eucalyptus urophylla × E. camaldulensis. Samples were treated in a superheated steam kiln at 160, 180, 200, and 220 °C for 3 h. The crystallinity, length-width ratio of fibers, and impact toughness of the heat-treated and untreated wood were determined. The cellulose crystalline regions experienced no obvious change. However, the length-width ratio and the relative crystallinity of the fibers increased as the temperature increased. Results indicated a clear inverse trend in the impact toughness and relative crystallinity. Finally, the results could provide a new method for non-destructive testing of wood.

  • Researchpp 1495-1505Ismail, H., Khoon, T. B., Hayeemasae, N., and Husseinsyah, S. (2015). "Effect of oil palm ash on the properties of polypropylene/recycled natural rubber gloves/oil palm ash composites," BioRes. 10(1), 1495-1505.AbstractArticlePDF

    In the present study, polypropylene, recycled natural rubber gloves, and oil palm ash composites (PP/rNRg/OPA) were prepared using an internal mixer. The effects that OPA loading had on the processability, tensile properties, morphology, and thermal stability of the PP/rNRg/OPA composites were investigated. The stabilization torque, tensile modulus, and thermal stability all increased; however, the elongation at break decreased as the OPA loading increased. The tensile strength increased to a maximum of 4 parts per hundred rubber (phr) OPA loading, and subsequently decreased. At 4 phr OPA, the filler was well-dispersed and had a good interaction with the matrix, whereas the agglomeration and detachment of OPA was observed at high loading rates of OPA in the PP/rNRg/OPA composite. Thermogravimetric analysis (TGA) indicated that the thermal stability of the composite increased as the OPA loading increased. Further evidence for the increased thermal stability can be found when analyzing the decomposition temperatures at different stages and maximum weight loss, where higher decomposition temperatures corresponded to composites with higher OPA loadings.

  • Researchpp 1506-1518Gaff, M., and Gašparík, M. (2015). "Influence of densification on bending strength of laminated beech wood," BioRes. 10(1), 1506-1518.AbstractArticlePDF

    This paper reports the influence of densification and cyclic loading on the bending strength of laminated beech (Fagus sylvatica L.). There have been many studies dealing with the bending strength of solid or laminated wood; however, densification is much less explored with respect to its use in the production of laminated wood. Laminated beech wood was loaded using three different numbers of cycles (1000, 2000, and 3000 cycles). Bending strength values of the cyclically loaded laminated wood ​​were compared with that of laminated wood that was not cyclically loaded. The laminated wood was formed by a combination of densified and non-densified veneers, as well as polyvinyl cholride (PVC) fabric. The results show that the laminated wood consisting of densified and non-densified veneers, eventually with PVC film included, reached higher values of bending strength in comparison with the traditional composition consisting of non-densified veneers. Densification had a strong impact on the bending strength. Laminated wood composed solely with densified veneers achieved by 17.4% higher bending strength compared to the reference. On the other hand, the number of cycles did not influence the bending strength to a meaningful extent.

  • Researchpp 1519-1527Chen, T., Niu, M., Wu, Z., and Xie, Y. (2015). "Effect of silica sol content on thermostability and mechanical properties of ultra-low density fiberboards," BioRes. 10(1), 1519-1527.AbstractArticlePDF

    The thermostability and mechanical properties of ultra-low density fiberboard (ULDF) were improved with the different content of silica sol. Microstructure and properties of ULDF were tested using scanning electron microscope (SEM), thermogravimetric analyzer (TGA), and microcomputer control electronic universal testing machine. The microstructures and the relative density of ULDFs were different with changes in Si sol content. The TGA results showed that the residual weight of ULDF was increased with the increasing content of silica sol and that the thermostability of ULDFs was improved. The modulus of rupture (MOR), modulus of elasticity (MOE), and the internal bond strength (IB) of ULDF were significantly improved from 0.12, 10.86, and 0.020 MPa to their maximum values of 0.23, 23.36, and 0.031 MPa while 4% silica sol was added.

  • Researchpp 1528-1542Liu, X., Wu, Y., Zhang, X., and Zuo, Y. (2015). "Study on the effect of organic additives and inorganic fillers on properties of sodium silicate wood adhesive modified by polyvinyl alcohol," BioRes. 10(1), 1528-1542.AbstractArticlePDF

    To enhance the properties of sodium silicate wood adhesive modified by PVOH (polyvinyl alcohol), different organic additives (compound A) and inorganic fillers (compound B) were added into the system. Their effects on the thermal stability and molecular structure of the composite adhesive were investigated by scanning electron microscopy (SEM), spectroscopic analysis (FT-IR), differential scanning calorimetry (DSC), and thermo- gravimetric analysis (TGA). The results showed that when the compound A consisting of amino acid, TEOS (Tetraethyl orthosilicate), sodium dodecyl sulfate with the mass ratio of 5:3:3 and B consisting of 50% active magnesium oxide and 50% nano-silica were added into the cross-linked sodium silicate adhesive system with the ratio of 90:3, the bonding and water resistance properties were improved by 97.6% and 46.7%, or 13.7% and 36% relative to pure and cross-linked sodium silicate, respectively. The addition of organic additives and inorganic fillers had a good effect on both the bonding strength and thermal stability of sodium silicate wood adhesive modified by PVOH.

  • Researchpp 1543-1552Xing, F., Chen, H., Zhang, S., Luo, B., Fang, P., Li, L., and Li, J. (2015). "Effect of p-cumylphenol on the mold resistance of modified soybean flour adhesive and poplar plywood," BioRes. 10(1), 1543-1552.AbstractArticlePDF

    Soy-based adhesive’s sensitivity to microbial attack is an aspect that restricts its future application. In an attempt to combat microbial attacks, several preservatives have been evaluated to determine their effects on mold resistance. In this paper, the inhibitory effect of p-cumylphenol was investigated by observing mold growth on modified soybean-flour adhesives and by evaluating the bonding strength and surface mold growth of bonded poplar plywood. Visual images, scanning electron microscopy, and tensile testing were used. The results showed that the initial microbial attack was delayed and the degree of attack was alleviated because of the preservatives. The bonding strength decreased in samples that contained p-cumylphenol after the samples were exposed to high humidity. Additionally, no correlation was observed between the degree of microbial growth on the surface of the plywood and amount of the preservatives. These results revealed that it was feasible to incorporate p-cumylphenol into soy-based adhesives as glue line treatment to improve the mold resistance. Finally, surface treatment of the veneer should be taken into consideration during the plywood manufacturing.

  • Researchpp 1553-1573Negrão, D. R., Sain, M., Leão, A. L., Sameni, J., Jeng, R., de Jesus, J. P. F., and Monteiro, R. T. R. (2015). "Fragmentation of lignin from organosolv black liquor by white rot fungi," BioRes. 10(1), 1553-1573.AbstractArticlePDF

    The mycelial growth ability of 13 white rot fungi were separately evaluated in kraft, organosolv, and soda black liquor agar-plates. The fungus able to best grow and decolorize black liquor agar-plates was grown in organosolv black liquor to investigate whether it reduced organosolv lignin molar mass. The fungus Bjerkandera adusta showed fair mycelial growth and decolorization ability in 10% black liquor-agar plates. To obtain low-molecular weight (MW) lignin, B. adusta was cultivated in 150-mL Erlenmeyer flasks containing 10% black liquor and maintained in a shaking culture for 15 days. Lignin was recovered from each Erlenmeyer flask by acid precipitation and was analysed by size exclusion chromatography (SEC) and Fourier transform infrared (FTIR) spectroscopy. The lowest MW of lignin from black liquor was observed on the 11th and 12th days, at 1461 and 1790 kDa, respectively, with the polydispersity close to 1.0, indicating that the molecules were similar in size. Fourier transform infrared spectra bands showed modification of the lignin structure during 9 days, with new bands appearing after five days of lignin biodegradation.

  • Researchpp 1574-1586Németh, R., Tsalagkas, D., and Bak, M. (2015). "Effect of soil contact on the modulus of elasticity of beeswax-impregnated wood," BioRes. 10(1), 1574-1586.AbstractArticlePDF

    The aims of this study were to use beeswax impregnation as a wood preservative method and to evaluate its suitability to protect wood species with low resistance to decay. Poplar (Populus × euramericana cv. Pannonia) and beech (Fagus sylvatica) samples were impregnated with beeswax and exposed to soil contact for 18 months. Impregnated samples were separated into three groups, on the basis of their degrees of pore saturation (DPS). With progressing decay, the load-bearing capacity and modulus of elasticity (MOE) of the woods decreased. After one month of soil contact, there was a marked decrease in MOE, which is explained by the increase in the moisture content of the wood. After 18 months, control samples were completely decayed. Nevertheless, impregnated samples showed less decay and a noticeable remaining load-bearing capacity. Impregnation efficiency had a pronounced effect on decay resistance. In both investigated species, samples with higher DPS resulted in less of a decrease in MOE than in samples with lower DPS. Although beeswax is a bio-based material, it showed noticeable decay resistance effects against soft rot. Scanning electron microscopy investigations showed that the impregnation has a barrier effect, mostly in the longitudinal direction, against the spread of the fungi.

  • Researchpp 1587-1598Guan, L., Tian, J., Cao, R., Li, M., Wu, Z., Nilghaz, A., Shen, W. (2015). "Surface modification of cellulose paper for quantum dot-based sensing applications," BioRes. 10(1), 1587-1598.AbstractArticlePDF

    Cellulose paper specimens with and without surface modification were compared in order to study their physicochemical compatibility with quantum dots (QDs) for biochemical sensing applications. Silane and chitosan modification methods were applied. The distribution of QDs deposited on untreated paper and papers modified with silane and chitosan were investigated in order to understand the interaction between QDs and fibre. Modified papers were shown to significantly reduce the undesirable redistribution of QDs during paper drying. The retention ability and thermal resistance of QDs to the loss of fluorescence on modified papers were also studied for the purpose of determining the most suitable paper surface modification for developing QD-Paper-based analytical devices (QD-PADs). Furthermore, chitosan-modified paper was used to design QD-PADs to quantify glucose concentration in aqueous samples; the quenching effect of the enzymatic product on the fluorescent emission of QDs was used as the indicator system. The change of fluorescence of QDs was measured by a simple in-house constructed fluorescence imaging system. The detection limit of glucose was 5 mg/dL, which is comparable with other reported paper sensors for detection of glucose.

  • Researchpp 1599-1616Antes, R., and Joutsimo, O. P. (2015). "Fiber surface and paper technical properties of Eucalyptus globulus and Eucalyptus nitens pulps after modified cooking and bleaching," BioRes. 10(1), 1599-1616.AbstractArticlePDF

    The SuperBatch™(SB), CompactCooking™(CC), and Lo-Solids™ (LS) modified cooking methods were evaluated relative to the cell wall surface and paper technical properties of bleached Eucalyptus globulus and Eucalyptus nitens. E. globulus pulps presented higher screened yield and brightness than E. nitens, which needed higher H-factor to reach a kappa number target. Independently of the cooking method or species, all the samples consumed similar amounts of ClO2 to reach a brightness of 90% ISO. E. nitens pulps showed lower carbohydrates and higher extractives content on the fiber surface, regardless of the cooking method. E. nitens presented slightly higher surface charge of the bleached pulps. Surface charges of CC and LS pulps were higher independently of cooked Eucalyptus species. Water retention value (WRV) for E. nitens pulps were higher than for E. globulus. No differences were observed in refinability of different cooking methods, however E. nitens pulps showed higher tensile and lower bulk compared to E. globulus. E nitens presented a thinner fiber cell wall than E. globulus. This seems to be more relevant for paper technical properties and WRV than fiber charge or surface composition. No correlation between surface composition, fiber surface properties, and paper technical properties among the cooking methods could be determined.

  • Researchpp 1617-1626Yu, H., Yu, W., Yang, L., Fang, C., and Xu, M. (2015). "Surface discoloration analysis and lignin degradation fragments identification of UV-irradiated moso bamboo (Phyllostachys pubescens Mazel)," BioRes. 10(1), 1617-1626.AbstractArticlePDF

    The SuperBatch™(SB), CompactCooking™(CC), and Lo-Solids™ (LS) modified cooking methods were evaluated relative to the cell wall surface and paper technical properties of bleached Eucalyptus globulus and Eucalyptus nitens. E. globulus pulps presented higher screened yield and brightness than E. nitens, which needed higher H-factor to reach a kappa number target. Independently of the cooking method or species, all the samples consumed similar amounts of ClO2 to reach a brightness of 90% ISO. E. nitens pulps showed lower carbohydrates and higher extractives content on the fiber surface, regardless of the cooking method. E. nitens presented slightly higher surface charge of the bleached pulps. Surface charges of CC and LS pulps were higher independently of cooked Eucalyptus species. Water retention value (WRV) for E. nitens pulps were higher than for E. globulus. No differences were observed in refinability of different cooking methods, however E. nitens pulps showed higher tensile and lower bulk compared to E. globulus. E nitens presented a thinner fiber cell wall than E. globulus. This seems to be more relevant for paper technical properties and WRV than fiber charge or surface composition. No correlation between surface composition, fiber surface properties, and paper technical properties among the cooking methods could be determined.

  • Researchpp 1627-1643Lee, K. C., Arai, T., Ibrahim, D., Prawitwong, P., Lan, D., Murata, Y., Mori, Y., and Kosugi, A. (2015). "Purification and characterization of a xylanase from the newly isolated Penicillium rolfsii c3-2(1) IBRL," BioRes. 10(1), 1627-1643.AbstractArticlePDF

    An extracellular xylanase was purified from the mesophilic fungus Penicillium rolfsii c3-2(1) IBRL. After three consecutive purification steps, the extracellular cellulase-free xylanase was successfully purified to homogeneity with a recovery yield of 24%. A single protein band of 35 kDa was detected by SDS-PAGE, which had an optimum catalytic activity at pH 5.0 and 50 °C. This purified enzyme was stable at pH 5 to 7, thermostable up to 55 °C, and retained up to 83% of its activity after 4 hours of pre-incubation. A kinetic study yielded estimated Km and Vmax values of 5.73 mg/mL and 691.6 µmol/min/mg, respectively. Thin layer chromatography experiments showed that the purified xylanase was capable of hydrolyzing xylotriose, xylotetraose, xylopentaose, and xylohexaose but not xylobiose, suggesting it is an endo-xylanase. Enzymatic hydrolysis of oil palm trunk residues by commercial enzymes supplemented with the purified xylanase showed a considerable increase in total sugar conversion compared with the commercial enzymes alone, suggesting that xylanase is a key enzyme in the hydrolysis of oil palm trunk residues.

  • Researchpp 1644-1656Kadimaliev, D., Kezina, E., Telyatnik, V., Revin, V., Parchaykina, O., and Syusin, I. (2015). "Residual Brewer's yeast biomass and bacterial cellulose as an alternative to toxic phenol-formaldehyde binders in production of pressed materials from waste wood," BioRes. 10(1), 1644-1656.AbstractArticlePDF

    Pressed composites can be produced from wood sawdust waste using modified yeast biomass, waste as a bio-adhesive, ultra-dispersed bacterial cellulose (UBC) as a binder, and preliminary chemical cross-linking. The materials obtained were not inferior to traditional materials based on the required levels of toxic phenol-formaldehyde resin and physical and mechanical parameters. Physical and mechanical properties of the materials depended on the amount and viscosity of the binder, as well as on the chemical structure and conditions of chemical cross-linking and modified UBC application. The strengths of the best examples of the materials obtained were approximately 17 to 20 MPa, the densities were in the range of 1207 to 1255 kg/m3, and the water absorption was less than 20%. During hot pressing, notable changes were observed in the wood particles at FTIR-ATR spectra frequencies of 3620 cm-1, 3600 to 3000 cm-1, 2920 cm-1, 2850 cm-1, 1770 cm-1, 1650 cm-1, 1560 cm-1, and 1089 cm-1. This is mainly due to the chemical and structural changes in lignin, hemicellulose, and binder.

  • Researchpp 1657-1666Kvietková, M., Gaff, M., Gašparík, M., Kminiak, R., and Kriš, A. (2015). "Effect of number of saw blade teeth on noise level and wear of blade edges during cutting of wood," BioRes. 10(1), 1657-1666.AbstractArticlePDF

    The effect of varying the number of saw blade teeth while transversally cutting beech (Fagus sylvatica L.) wood on the noise level and saw blade lifetime between two sharpenings was tested. The experiment was carried out with raw beech wood samples with dimensions of 25 x 100 x 1000 mm and circular saw blades with cemented carbide tips (24, 40, and 60 teeth). The saw blade diameters were identical (D = 250 mm), as were the cutting wedge angle geometries (α = 15°, β = 60°, γ = 15°). The saw blades were selected based on commonly used blades (in the Czech Republic and Slovakia) for the transversal cutting of the given wood species. Neither the cutting speed (vc = 62 m/s) nor the feed force (Fp = 75 N) were changed during the cutting process. The results suggest that the number of saw blade teeth is an important factor that affects the noise level of saw blade during sawing as well as the wear of cutting edge.

  • Researchpp 1667-1674Dilik, T., and Hiziroglu, S. (2015). "Some properties of linoleum and wood laminated flooring panels with magnesium substrate," BioRes. 10(1), 1667-1674.AbstractArticlePDF

    This paper presents some of the properties of commercially manufactured laminated flooring having magnesium oxide substrate. Laminated flooring samples with thin veneer of walnut wood and linoleum were tested for their bending characteristics, internal bonding strength, thickness swelling, and surface roughness. The highest modulus of elasticity value of 583,000 psi was found for the samples loaded in the direction of wood veneer overlay. Linoleum overlaid samples resulted in 461,000 psi for the corresponding value. Wood overlaid samples also showed 8% lower internal bond strength values than those of linoleum laminated specimens. Based on the roughness evaluation of the samples conditioned at 55% and 95% relative humidity levels employing a stylus type equipment, no significant adverse effect of high humidity exposure on their surface quality was determined. It appears that magnesium panels overlaid with solid wood and linoleum veneer sheets could serve as value-added flooring with acceptable properties.

  • Researchpp 1675-1685Yang, T., and Ma, E. (2015). "Dynamic sorption and hygroexpansion of wood subjected to cyclic relative humidity changes. II. Effect of temperature," BioRes. 10(1), 1675-1685.AbstractArticlePDF

    To investigate the effect of temperature on the dynamic sorptive and hygroexpansive behavior of wood, poplar (Populus euramericana cv.) specimens, 20 mm in radial (R) and tangential (T) directions with two thicknesses of 4 mm and 10 mm along the grain, were exposed to a sinusoidally varying relative humidity between 45 and 75% for 1, 6, and 24 h at 25 and 40 °C. Moisture changes, as well as radial and tangential dimensional changes measured during cycling, produced the following results: moisture and dimensional changes in the specimens were generally sinusoidal, and an increase in temperature led to decreased moisture contents and transverse dimensions, accordingly. The amplitude of moisture and dimensional changes was in positive correlation with temperature, while the phase lag was inversely related to temperature. Sorption hysteresis and swelling hysteresis decreased as temperature increased. Both moisture sorption coefficient (MSC) and humidity expansion coefficient (HEC) were supposed to share the approximate value for different thick specimens if cyclic period is sufficiently long. Transverse anisotropy could be found under dynamic conditions, and the T/R was about 1.65 to 1.75, varying sinusoidally with a phase difference of about a half cycle to the imposed relative humidity.

  • Researchpp 1686-1695Özkaya, K., Ayrilmis, N., and Özdemir, S. (2015). "Potential use of waste marble powder as adhesive filler in the manufacture of laminated veneer lumber," BioRes. 10(1), 1686-1695.AbstractArticlePDF

    The waste powder produced during the manufacture of marble, which is presently mostly discarded in landfills, has the potential for higher-valued usage. Recycling marble waste powder will contribute to the protection of nature as well as economic gain. The potential use of waste marble powder as filler in the adhesive for manufacturing of laminated veneer lumber (LVL) was investigated in this study. With this objective, LVL panels were manufactured by adding marble factory waste powder in different ratios to polyvinyl acetate (PVAc) and urea-formaldehyde (UF) adhesives. The waste powders of beige marbles and travertine marbles were mixed by weight with adhesives in the percentage levels of 0%, 10%, 20%, 30%, 40%, and 50%. Physical and mechanical tests were performed on the specimens obtained from the LVL panels. According to the results obtained from the present study, as compared to the control specimens, higher mechanical performance was obtained with the waste beige marble powder at high contents and with the waste travertine marble powder at low contents with the PVA adhesive. A poorer mechanical performance was found in the travertine powder with the UF adhesive. The dimensional stability of LVLs containing travertine powder was better than that of the LVLs containing beige marble powder.

  • Researchpp 1696-1714Zhu, W., and Theliander, H. (2015). "Precipitation of lignin from softwood black liquor: An investigation of the equilibrium and molecular properties of lignin," BioRes. 10(1), 1696-1714.AbstractArticlePDF

    Extracting lignin from black liquor is an attractive option in modern pulp mills as a unit process for a combined biorefinery. The lignin obtained can be utilized as solid fuel or other high-value added products. The precipitation equilibrium of kraft lignin from softwood black liquor was studied in this work. It was found that with decreasing pH and temperature, or increasing ion strength, the solid yield increases. Moreover, precipitated softwood kraft lignin has a higher molecular weight and contains lower amounts of carbohydrates and phenolic groups than lignin precipitated from mixed hardwood/softwood black liquor. The content of methoxyl groups in softwood kraft lignin was found to decrease with increasing precipitation yield. An empirical model for estimating the precipitation yield of lignin was proposed and evaluated.

  • Researchpp 1715-1729Zhai, M., Shi, G., Wang, Y., Mao, G., Wang, D., and Wang, Z. (2015). "Chemical compositions and biological activities of pyroligneous acids from walnut shell," BioRes. 10(1), 1715-1729.AbstractArticlePDF

    Seven kinds of pyroligneous acids were collected at different temperature ranges (K7-1: 90 to 140 ºC ; K7-2: 140 to 190 ºC; K7-3: 190 to 240 ºC; K7-4: 240 to 290 ºC; K7-5: 290 to 340 ºC; K7-6: 340 to 440 ºC; and K7-7: 440 to 480 ºC). The chemical compositions of the pyroligneous acids were determined by GC-MS. Moreover, the biological activities of pyroligneous acids were investigated by a foliar spray experiment of rape using the pyroligneous acids collected at 90 to 480 ºC. The physiological and chemical responses of pyroligneous acids, including the content of soluble protein and the superoxide dismutase (SOD) activity, were detected. The results of GC-MS analysis showed that the chemical profiles of pyroligneous acids varied with pyrolysis temperature. About 62 kinds of compounds belonging to 8 groups were identified, including ketones, phenols, organic acids, ester, benzene and its derivatives, aldehydes, alcohols, and sugar derivatives. Finally, the pyroligneous acids from walnut shell were applied in foliar spray for rape (Brassica campestris L.). The results demonstrated that pyroligneous acid from walnut shell with a low concentration significantly enhanced the content of soluble protein and the activity of SOD in rape leaves.

  • Researchpp 1730-1746Then, Y. Y., Ibrahim, N. A., Zainuddin, N., Chieng, B. W., Ariffin, H., and Wan Yunus, W. M. Z. (2015). "Influence of alkaline-peroxide treatment of fiber on the mechanical properties of oil palm mesocarp fiber/poly(butylene succinate) biocomposite," BioRes. 10(1), 1730-1746.AbstractArticlePDF

    In this work, the surface of oil palm mesocarp fiber (OPMF) was modified via alkaline-peroxide treatment with hydrogen peroxide under alkaline conditions. The effect of the treatment on the chemical composition and microstructure of the fiber was examined using chemical analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. The treatment resulted in the removal of lignin, hemicellulose, and waxy substances from the fiber and increased its surface roughness and crystallinity. The eco-friendly biocomposite was made from poly(butylene succinate) (PBS) and chemically treated fiber at a weight ratio of 30:70, and was fabricated via a melt-blending technique followed by hot-pressed moulding. The results indicated that alkaline-peroxide treatment of the fiber improved the tensile strength, tensile modulus, and elongation at break of the OPMF/PBS biocomposite by 54, 830, and 43%, respectively. The SEM analysis revealed improvement of the interfacial adhesion between the chemically treated fiber and the PBS. This work demonstrates that alkaline-peroxide treatment of fiber is beneficial prior to its use in fabricating biocomposites.

  • Researchpp 1747-1756Midukov, N. P., Schrinner, T., Grossmann, H., Smolin, A. S., and Kurov, V. S. (2015). "Effect of virgin fiber content on strength and stiffness characteristics of a three-layer testliner," BioRes. 10(1), 1747-1756.AbstractArticlePDF

    Research results on the improvement of the strength properties of a testliner produced from recovered paper and kraft pulp are presented in this work. The effects of kraft pulp content and the fractionation of secondary fiber on testliner strength properties were determined. Primary and recovered paper pulp was produced using standard procedures. The testliner consisted of three layers, totaling a grammage of 150 g/m2, when the center layer was made solely from the short fiber fraction of recovered paper. The weight of the surface layers each comprised 30% of the total handsheet weight, and the center layer weight was 40%. The virgin fiber content of the upper and lower layers was varied from 0% to 30% of the corresponding handsheet layer weight. The breaking length, tensile strength, modulus of elasticity, longitudinal and bending rigidity, and bursting and plybond strength, along with the effects of virgin fiber dosage on the strength properties were experimentally determined. As a result, a composition was proposed that showed the rational arrangement of virgin fibers as well as short- and long-fiber fractions of recovered paper in the layers. A comparison of the strength properties of the testliner using standard parameters demonstrated the advantages of the testliner producing technology.

  • Researchpp 1757-1772Wang, Y. B., Gao, C., Zheng, Z., Liu, F. M., Zang, J. Y., and Miao, J. L. (2015). "Immobilization of cold-active cellulase from Antarctic bacterium and its use for kelp cellulose ethanol fermentation," BioRes. 10(1), 1757-1772.AbstractArticlePDF

    Immobilization is an effective way to solve the problem associated with the application of cold-active cellulase in industrial processes. In this study, a cold-active cellulase from the Antarctic psychrophilic bacterium Pseudoalteromonas sp. NJ64 was obtained, immobilized, and analyzed for optimal immobilization conditions. Then it was used in kelp cellulose ethanol fermentation, achieving a higher purity level of kelp cellulose ethanol. The enzymatic activity of this cold-active cellulase was 49.7 U/mL. The optimal immobilization process conditions were as follows: sodium alginate, 30 g/L; calcium chloride, 5 g/L; glutaraldehyde, 0.4%; and cross-linking time, 5 h. Under these conditions, the activity recovery rate was 51.58%. The optimum reaction temperature was at 40 °C, the optimum initial pH was 9.0, and the relative enzyme activity was 58.37% after being recovered seven times. A higher purity level of kelp cellulose ethanol has reached (37.37%). Immobilized cold-active cellulase can effectively hydrolyze the cellulose of kelp residue, which is a valuable component of cellulose bio-ethanol production and will have broad implications in the development of the ethanol industry in China.

  • Researchpp 1773-1789Zhang, M., Ding, C., Chen, L., and Huang, L. (2015). "Preparation of tannin-immobilized collagen/cellulose bead for Pb(II) adsorption in aqueous solutions," BioRes. 10(1), 1773-1789.AbstractArticlePDF

    Bayberry tannin-immobilized collagen/cellulose bio-adsorbent (BT-collagen/cellulose) was prepared via the reaction of bayberry tannin with the amino group of collagen in collagen/cellulose blends. Compared with collagen/cellulose beads without tannin, BT-collagen/cellulose had a more compact structure and higher thermal stability. Furthermore, the crystalline structure of cellulose in BT-collagen/cellulose was preserved. The adsorption properties of BT-collagen/cellulose to Pb(II) in aqueous solution were investigated and compared with those of collagen/cellulose. The adsorption of Pb(II) on both of the two bio-adsorbents reached the maximum at pH near 5.5. Based on the mass content of collagen, the equilibrium adsorption capacity of BT-collagen/cellulose at 25 °C was 1.352 mmol/g, according to Langmuir isotherms, which was higher than that of collagen/cellulose (0.345 mmol/g). In kinetics studies, both of the two bio-adsorbents reached equilibrium within ~240 min, and the experimental data could be well fitted by the pseudo-second-order rate model. Nevertheless, BT-collagen/cellulose had a better reusability after three cycles of adsorption-desorption.

  • Researchpp 1790-1802Gašparík, M., Barcík, Š., Borůvka, V., and Holeček, T. (2015). "Impact of thermal modification of spruce wood on screw direct withdrawal load resistance," BioRes. 10(1), 1790-1802.AbstractArticlePDF

    This paper reports on the dependence of screw direct withdrawal load resistance on thermal modification of spruce wood. Screw direct withdrawal load resistance was measured in native and thermally modified spruce wood. The thermal modification was performed at three different temperatures: 140, 180, and 220 °C. Tests were carried out using two types of screws in three anatomical directions. The effect of the thermal modification was unambiguous: the screw direct withdrawal load resistance decreased with increasing modification temperatures. The largest decline 44.2% was found in the axial direction and at a temperature of 200 °C, while the lowest decrease 4.1% was found in radial direction and at temperature 140 °C for conventional screws without pre-drilling. The highest values were identified in the radial direction, and the lowest in the axial direction. While conventional screws without pre-drilled holes may be regarded as the most suitable, the self-drilling screws achieved the lowest values.

  • Researchpp 1803-1824Razali, N., Salit, M. S., Jawaid, M., Ishak, M. R., and Lazim, Y. (2015). "A study on chemical composition, physical, tensile, morphological, and thermal property of roselle fibre: Effect of fibre maturity," BioRes. 10(1), 1803-1824.AbstractArticlePDF

    Roselle fibre is a type of natural fibre that can be utilized as apotential reinforcement filler in polymer composites for different applications. This work investigates the chemical, physical, mechanical, morphological, and thermal characteristics of roselle fibre at different levels of maturity (3, 6, and 9 months). The diameter of roselle fibre increases as the plant matures. However in contrast to this, the moisture content and water absorption of roselle fibre decrease as the plant matures. Chemical content of roselle fibres from plants of different ages indicate that as the plant matures, the cellulose content decreases. Tensile strength of roselle fibre decreases from 3 months old to 9 months old. The cross section of roselle fibre shows a typical morphology of bast fibre, where there is a lumen in the central of fibre. Thermal analysis results show that the effect of thermal decomposition of roselle fiber is almost the same for all plant ages. It is concludedthat roselle fibres can be used as reinforced material for manufacturing of polymer composites. Based on its excellent properties, roselle fibres are suitable for different applications such as automotive and building components at lower cost.

  • Researchpp 1825-1844Márquez-Montesino, F., Correa-Méndez, F., Glauco-Sánchez, C., Zanzi-Vigouroux, R., Rutiaga-Quiñones, J. G., and Aguiar-Trujillo, L. (2015). "Pyrolytic degradation studies of Acacia mangium wood," BioRes. 10(1), 1825-1844.AbstractArticlePDF

    Pyrolytic degradation of Acacia mangium wood was studied. The chemical composition of biomass, immediate and elemental analyses and calorific value for biomass and char, were determined. The standard and the derivative curve thermogravimetric analysis (TGA and DTG) were obtained. Devolatilization maximum of values between 250±20 °C and 380±20 °C were observed, with completion after 2 h, which confirms the selection of 2 hours for pyrolysis. Kinetic study was performed at different heating rates for a conversion rate from 20% to 80%. Average values of activation energy for temperature in degrees K of 228.57 kJ/mol for Biomass 1 and 199.36 kJ/mol for Biomass 2 were obtained by the isoconversion method of FWO. The lower value of activation energy for Biomass 2 was related to the possible catalytic activity of ash. The values of correlation coefficient from 0.9418 to 0.9946 for Biomass 1 and from 0.8706 to 0.9918 for Biomass 2, indicate the reliability of the first-order reaction model. The caloric values obtained were: Biomass 1 (16962 kJ/kg), Biomass 2 (16974 kJ/kg), chars from Biomass 1 (between 23731 y 26 942 kJ/kg) and gas from Biomass 1 and Biomass 2 (3858.7 and 4859.4 kJ/m3, respectively).

  • Researchpp 1845-1856Alves, R. C., Mantilla, J. N. R., Bremer, C. F., and Carrasco, E. V. M. (2015). "Application of acoustic tomography and ultrasonic waves to estimate stiffness constants of Muiracatiara Brazilian wood," BioRes. 10(1), 1845-1856.AbstractArticlePDF

    Determination of the stiffness constants of Muiracatiara wood (Astronium lecointei) was performed using Fakopp 3D acoustic tomography and James V Mk II ultrasound devices. Specific gravity, moisture content, and compression perpendicular to grain tests followed standard Brazilian requirements. Statistical tests were calculated to 99% confidence intervals. Using Christoffel’s equation, equality between stiffness constants and static modulus of elasticity occurred only when using the acoustic tomography device. These results show the importance of the acoustic tomography device, not only to detect defects, but also in determining elastic constants of wood.

  • Researchpp 1857-1868Chen, Y., Wan, J., Ma, Y., Dong, X., Wang, Y., and Huang, M. (2015). "Fiber properties of de-inked old newspaper pulp after bleaching with hydrogen peroxide," BioRes. 10(1), 1857-1868.AbstractArticlePDF

    Hydrogen peroxide was applied to bleach recycled de-inked pulp from old newspaper (ONP) in this study. Following single-stage bleaching, the fiber properties of the pulp (viz. brightness, yield, fiber length, fiber charge, and strength properties) were determined. Finally, the crystal structure of cellulose, fiber surface morphology, and functional groups of the control pulp and the bleached pulp using hydrogen peroxide were analyzed by XRD, SEM, and FT-IR, respectively. The single-stage peroxide bleaching applied to the de-inked ONP pulp could produce a high brightness pulp of 58% ISO at a yield of 92%. Fiber length decreased after bleaching treatment. The crystallinity index of cellulose of de-inked ONP pulp during bleaching or rinsing treatment increased due to the dissolution of cellulose in amorphous regions and/or the dissolution or loss of non-cellulosic constituents (hemicelluloses and lignin). Hydrogen peroxide bleaching resulted in fibrillation and longitudinal tearing of the fiber surface due to delignification, which led to an increase in the paper strength. FT-IR data showed that the content of carboxylic acid groups decreased during peroxide bleaching. The main chromophore (conjugated carbonyl groups) and the guaiacyl units of the pulp were damaged after bleaching resulting in delignification.

  • Researchpp 1869-1878Wang, L., Shi, C., and Wang, L. (2015). "Fabrication of magnetic and EMI shielding wood-based composite by electroless Ni-Fe-P plating process," BioRes. 10(1), 1869-1878.AbstractArticlePDF

    A Ni-Fe-P alloy coating was applied to Triplochiton scleroxylon veneers to prepare a magnetic, corrosion-resistant, electromagnetism-shielding wood-based composite. The effects of solution pH on metal deposition, surface resistivity, crystal structure, and the chemical composition of the coatings were investigated. The electro-conductivity, anti-corrosion properties, and magnetic and electromagnetic shielding performances were also measured. The results showed that increasing the pH favored the co-deposition of nickel and iron; metal deposition increased and surface resistivity decreased. The Ni-Fe-P alloy coatings obtained at pH values between 8.8 and 9.6 were all crystalline. VSM data revealed that the addition of elemental Fe to the deposits remarkably increased the magnetic properties of the products. The anti-corrosion properties of Ni-Fe-P coatings were higher than those of Ni-P coatings prepared in 3.5 wt.% NaCl solution. The electromagnetic shielding effectiveness value of Ni-Fe-P plated veneer reached 45 to 60 dB at frequencies ranging from 9 kHz to 1.5 GHz.

  • Reviewpp 1879-1914Ioelovich, M. (2015). "Recent findings and the energetic potential of plant biomass as a renewable source of biofuels - A review," BioRes. 10(1), 1879-1914.AbstractArticlePDF

    Nowadays the main sources of energy are petroleum, coal, and natural gas. However, these fossil sources are not reproduced in nature; on a human timescale their reserves are exhausted permanently and run down. Considerable attention in recent years has been given to plant biomass, which in contrast to the fossil sources is continuously renewed in nature. In this critical review the use of non-edible plant biomass for production of various kinds of biofuels is considered. To generate energy, plant biomass either can be burned directly or it can be used after its conversion into carbonized solid fuel (e.g. biochar), liquid fuels (bioethanol, biodiesel, bio-oil), or gases (biogas). Among various biofuels, production of bioethanol has potential to be the most attractive if recent technological advances become implemented, such that the co-production of ethanol and valuable byproducts can be combined together with recycling of solid and liquid wastes. A comparative analysis of energetic potential of biomass and various kinds of biofuels revealed that the most efficient way to produce energy is by direct burning of the plant biomass in a pelletized form, while the burning of such amount of the solid, liquid, or gaseous biofuel, which can be obtained from the plant material, gives a much smaller energetic effect. Novel types of pellets, as well as solid/liquid biofuels, having improved fuel characteristics are described.

  • Reviewpp 1915-1963Pintiaux, T., Viet, D., Vandenbossche, V., Rigal, L., and Rouilly, A. (2015). "Binderless materials obtained by thermo-compressive processing of lignocellulosic fibers: A comprehensive review," BioRes. 10(1), 1915-1963.AbstractArticlePDF

    As the worldwide demand for fuels and materials increases, fossil resources are decreasing and global warming is a concern, and thus the need for alternative solutions is high. In the industries of furniture and housing, particleboards are interesting materials, as they reutilize wastes from other industries (wood, agriculture) although they also rely on chemical binders that are petroleum-based and toxic. A very promising alternative is then clearly identified in finding ways to produce binderless boards and associated materials. This review considers the state of the art in the field of binderless board production, and other processes making it possible to turn raw plant fibers into structural materials without using any external chemistry. The mechanical properties and water resistance are collected and compared. Identified chemistry changes occurring during the thermo-compressive process are discussed with an aim towards understanding of the mechanisms of cohesion.

  • Reviewpp 1964-1985Liu, Y., Ren, X., and Liang, J. (2015). "Antibacterial modification of cellulosic materials," BioRes. 10(1), 1964-1985.AbstractArticlePDF

    The proliferation of bacteria on the surfaces of cellulosic materials during their use and storage can have negative effects on the materials themselves and on consumers. People’s demands for materials with antibacterial properties have been satisfied in recent years because of the emergence of various antibacterial compounds. This paper reviews recent research and development progress in antibacterial modification of cellulosic fibers using various biocides such as N-halamines, quaternary ammonium salts, chitosan, triclosan, and nanoparticles composed of noble metals and metal oxides. Antibacterial mechanisms and treating methods for antibacterial cellulosic materials are also involved in this paper.