NC State
  • Editorialpp 5774-5777Turon, X., Venus, J., Arshadi, M., Koutinas, M., Lin, C. S. K., and Koutinas, A. (2014). "Food waste and byproduct valorization through bio-processing: Opportunities and challenges," BioRes. 9(4), 5774-5777.AbstractPDF
    The bioeconomy era will rely on efficient fractionation of renewable resources via integrated biorefineries. The food supply chain waste, despite its inherent variability, could evolve into an important industrial feedstock on account of its availability, versatility, and sustainability, for the production of bio-based products. Waste streams generated from all stages of the life cycle of food products could be refined into different fractions, which will be either purified to high-value molecules or converted via green chemical and/or biotechnological routes for the production of bio-based products. A working group of the EUBis COST Action TD1203 is taking steps to gather a critical mass of knowledge and expertise to create innovation and technological breakthroughs.
  • Editorialpp 5778-5781Naylor, A. (2014). "Can wood be used as a bio-mechanical substitute for bone during evaluation of surgical machining tools?" BioRes. 9(4), 5778-5781.AbstractPDF
    It is often not possible to machine human or animal tissue, such as bone, in a typical engineering workshop due to the numerous health risks associated. Further to this, currently used synthetic substitutes are also unsuitable for machining. This is mainly due to the aerosolization of harmful particles created during the machining process. It is however essential to thoroughly test and evaluate emerging orthopedic cutting tool designs, particularly when considering that osteonecrosis occurs at as low as 47 °C cutting temperature. It is proposed here that a composite bone model can be constructed using a dense hardwood to represent the hard cortical bone outer shell, and a less dense softwood to represent the spongy cancellous bone interior.
  • Editorialpp 5782-5783Hubbe, M. A. (2014). "Puzzling aspects of the hydrophobic sizing of paper and its inter-fiber bonding ability," BioRes. 9(4), 5782-5783.AbstractPDF
    Internal sizing agents make it possible to prepare water-resistant paper from an aqueous suspension comprising water-loving fibers and an emulsified hydrophobic agent. Why doesn’t the hydrophobic treatment get in the way of inter-fiber bonding? The answer appears to involve the order in which nano-scale events happen during the manufacture of paper. It appears that the inter-fiber bonded areas develop first. Molecular distribution of the hydrophobic agents appears to happen later, especially during the later stages of evaporative drying. The topic seems to be crying out for someone to carry out appropriate experiments to shed more light on the mechanism.
  • Researchpp 5784-5793Kotlarewski, N. J., Ozarska, B., and Gusamo, B. K. (2014). "Thermal conductivity of Papua New Guinea balsa wood measured using the needle probe procedure," BioRes. 9(4), 5784-5793.AbstractPDF
    A study was undertaken with the aim to determine thermal properties of balsa wood grown in plantations in Papua New Guinea. Thermal conductivity values were measured using the needle probe procedure according to ASTM D5334 (2008). The mean thermal conductivity results of balsa were in the range of 0.0381 W/mK to 0.0665 W/mK, similar to other materials currently used as insulators in the construction industry. A balsa sample with a density of 113 kg m3 had the lowest thermal conductivity value, 0.0339 W/mK, across the tangential and radial wood grain directions. Balsa is exported from Papua New Guinea mostly as end-grain panels to international markets to optimise its strength properties in the axial direction for applications that are exposed to compressive forces. This study revealed that there is the opportunity for Papua New Guinea balsa processors to consider producing perpendicular-grain panels for insulation markets, as the mean thermal conductivity values in this direction can be as low as 0.0381 W/mK, which is much lower than the thermal conductivity of the current end-grain panels at 0.0665 W/mK. The finding creates a potential design opportunity for balsa processors to consider entering new commercial markets to promote Papua New Guinea-grown balsa.
  • Researchpp 5794-5800Sun, F., Jiang, Z. Sun, Q., and Lu, F. (2014). "Changes in chemical composition and microstructure of bamboo after gamma ray irradiation," BioRes. 9(4), 5794-5800.AbstractPDF
    Changes in bamboo composition and microstructure following 60Co gamma (γ) ray irradiation were investigated by solid state 13C cross-polarization (CP) magic-angle spinning (MAS) spectroscopic nuclear magnetic resonance spectrometry (NMR) and a field emission scanning electron microscope (FESEM). The results indicated that irradiation doses lower than 100 KGy resulted in the degradation of hemicelluloses via scission of molecular chains, but there was also repolymerization and condensation in lignin. Irradiation doses higher than 100 KGy resulted in the degradation of cellulose, hemicelluloses, and lignin by significant oxidation reaction and partial scission of biopolymer chains to yield more small fragments with carbonyl groups.
  • Researchpp 5801-5816Gupta, G., Sahai, V., and Gupta, R. K. (2014). "Thermal stability and thermodynamics of xylanase from Melanocarpus albomyces in presence of polyols and salts," BioRes. 9(4), 5801-5816.AbstractPDF
    An extracellular xylanase from the thermophilic fungus Melanocarpus albomyces IIS 68 was evaluated for its activity and stability in the presence of polyols and salts at 60 °C, and found to be an effective protecting agent for thermal deactivation of enzyme. Response surface methodology was employed to study the synergistic effects of glycerol and NaCl (thermo-stabilizers) for xylanase stability. The addition of these thermo-stabilizers resulted in more than a 10-fold increment in enzyme half-life. Activation energy (Ea) and thermodynamic parameters such as ∆H, ∆G, and ∆S were calculated for the thermal inactivation of free and immobilized xylanase. The immobilized enzyme underwent substantially less conformational changes because of its enhanced stability and increased compactness, providing better thermo-stability at elevated temperatures. These findings suggest that the combined effect of glycerol and sodium chloride serves as a potential stabilizer for extracellular thermophilic xylanase, which finds commercial application in many industries, especially in the pulp and paper industry.
  • Researchpp 5817-5830Peng, Y., Liu, R., and Cao, J. (2014). "Effects of antioxidants on photodegradation of wood flour/polypropylene composites during artificial weathering," BioRes. 9(4), 5817-5830.AbstractPDF
    The influence of antioxidants and of their compound systems were evaluated relative to the photodegradation of wood flour/polypropylene (WF/PP) composites using ultraviolet accelerated weathering. Six groups of samples were exposed in an accelerated weathering tester for a total duration of 960 h. The surface color, gloss, and flexural properties of the samples during weathering were tested. In addition, the weathered surfaces were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). The results revealed the following: (1) after weathering, all samples showed significant color fading and gloss change; (2) composites containing antioxidants showed less loss of flexural strength, fewer surface cracks, and better thermal stability after weathering than the control composite; (3) the crystallinity of polypropylene increased in weathered samples due to recrystallization of lower molecular weight polypropylene; and (4) antioxidant 168 (AO-168) was beneficial to color stability at the early stage of weathering, while composites containing 0.2% antioxidant 1010 (AO-1010) and 1.0% AO-168 (AO-1) maintained the highest retention ratios of flexural properties during weathering.
  • Researchpp 5831-5844Lou, B., Wu, S., Wang, X., Ma, K., and Li, M. (2014). "Experimentation and simulation of the combustion of biomass briquettes in southern China," BioRes. 9(4), 5831-5844.AbstractPDF
    The thermogravimetry (TG) of typical biomass briquettes used as fuel in southern China was analysed to investigate the influences of fuel grain size and heating rate on combustion. The results suggested that grain size and heating rate exerted little influence on combustion. In accordance with the data and the TG results obtained from the fuel, a biomass grate incinerator process was numerically simulated using fluid dynamics-based incinerator code (FLIC) software to obtain the solid phase temperature distribution of the fuel along the bed length, the spatial temperature distribution of flue gas, and the underlying variation laws of the primary components. A comparison of the mass-loss curves from the numerical simulation to the TG analysis demonstrated that the two curves exhibited consistently staged variations, including dehydration and drying, fast pyrolysis and combustion of volatiles, and the burnout of residual carbon. The specific characteristics of the fuel obtained from these tests improved the accuracy of the numerical simulation, while the variations in temperature and components obtained were conducive to optimising the combustion process of a biomass incinerator.
  • Researchpp 5845-5857Teng, Y., Ding, J., Wang, B., Guo, X., and Cao, P. (2014). "Cutting forces and chip morphology in medium density fiberboard orthogonal cutting," BioRes. 9(4), 5845-5857.AbstractPDF
    The influence of rake angle, cutting speed, and uncut chip thickness on cutting forces and chip morphology in medium density fiberboards orthogonal cutting was investigated. With regard to the normal cutting force and the feed force recorded, there were important variations when machining conditions were modified, or when some tool characteristics were changed. The findings led to the conclusion that there was a close relationship between the cutting conditions and chip formations as well as the cutting forces. Such forces were found to be particularly sensitive to changes in uncut chip thickness, as well as showing dependence on the cutting speed of the tools in orthogonal cutting.
  • Researchpp 5858-5870Li, H., Li, C., Chen, H., Zhang, D., Zhang, S., and Li, J. (2014). "Effects of hot-pressing parameters on shear strength of plywood bonded with modified soy protein adhesives," BioRes. 9(4), 5858-5870.AbstractPDF
    The heating rate of the core layer of plywood during hot-pressing is of great importance to the final quality of the plywood and is affected by many factors, such as the hot-pressing temperature (THP), hot-pressing pressure (PHP), hot-pressing time (tHP), veneer layers, and moisture content. In this study, multi-plywood using modified soy protein (MSP) adhesives prepared to investigate the effects of THP, t HP, and veneer layers on the core layer temperature during hot-pressing. The results indicated that all the core layer temperature curves were divided into four stages. The first constant temperature stage and the slow warming stage were decisive with respect to the time needed for the core layer to reach the THP. The time of moisture vaporization was approximately 400 s in the 3-layer plywood and approximately 900 s in the 5-layer plywood. In order to get an ideal strength the tHP should greater than the time of moisture vaporization; therefore in theory, the optimum parameters of the 3-layer plywood production were tHP of 600 to 720 s and THP of 120 to 125 °C. The research provides a theoretical basis for optimizing the hot-pressing of plywood.
  • Researchpp 5871-5882Zhao, M., Wang, Y., Zhang, C., Li, S., Huang, Z., and Ruan, W. (2014). "Synergistic and pretreatment effect on anaerobic co-digestion from rice straw and municipal sewage sludge," BioRes. 9(4), 5871-5882.AbstractPDF
    Anaerobic digestion is considered to be a priority disposal technology for rice straw and sewage sludge. In this study, the synergistic and alkali-treat effect on co-digestion of rice straw and sewage sludge was investigated. The results indicated that the co-digestion of alkali-treated rice straw and sewage sludge had the best biogas yield of 338.9 mL/gVS, which was 1.06 and 1.75 times that of either alkali-treated rice straw or sewage sludge alone, respectively. The actual biogas and methane yields of a co-digestion group with raw rice straw and sewage sludge (G4) increased 26.39% and 24.79% relative to the theoretical calculation based on raw rice straw digestion (group G2) and sewage sludge digestion (group G5), suggesting that a synergistic effect occurred during the co-digestion process. The maximum concentration of volatile fatty acids (VFA) was 4860 mg/L on the 4th day in the sewage sludge group. Xylanase activity reached a maximum of 10.55 U/mL on the 6th day in the alkali-treated rice straw group, while the concentration of protease enzyme was relatively higher in the sewage sludge group than in others. The removal rates of cellulose and hemicellulose in groups with alkali treatment were 32.25% and 36.96% (G1) and 40.86% and 41.61% (G3), higher than that of groups without treatment.
  • Researchpp 5883-5892Fan, H., Wang, S., and Liu, J. (2014)."The influence of particle size of starch- sodium stearate complex modified GCC filler on paper physical strength," BioRes. 9(4), 5883-5892.AbstractPDF
    Ground calcium carbonate (GCC) was modified with starch/sodium stearate complexes and used to prepare modified GCC of different size by use of a BSJ-200 oscillating sieving machine. Modified GCC was characterized by scanning electron microscopy (SEM) and particle size analysis. Eight kinds of modified GCC of different size and a kind of modified GCC without screening were used in papermaking and the paper strength properties, especially in tensile, tear, and burst index, were investigated. It was found that the size of modified GCC played an important role in the physical properties of the paper. The best size of modified GCC was within the range 35 to 54 µm.
  • Researchpp 5893-5905Chen, D., Zhou, J., Zhang, Q., Zhu, X., and Lu, Q. (2014). "Upgrading of rice husk by torrefaction and its influence on the fuel properties," BioRes. 9(4), 5893-5905.AbstractPDF
    Torrefaction refers to thermal treatment of biomass at 200 to 300 °C in an inert atmosphere, which may increase the heating value while reducing the oxygen content and improving the storability. In this study, the effects of torrefaction temperatures on the properties of rice husk were analyzed. Torrefaction experiments were performed using a lab-scale device designed to reduce heat and mass transfer transient effects. A new method is described for clarifying torrefaction time and minimizing experimental error. Results from analysis of torrefaction temperatures (200, 230, 260, and 290 °C) support the supposition that the fiber structure is damaged and disrupted, the atomic oxygen ratio is reduced, the atomic carbon ratio and energy density are increased, the equilibrium moisture content is reduced, and the hydrophobic properties of rice husk are enhanced. The data presented in this paper indicate that torrefaction is an effective method of pretreatment for improving rice husk. Torrefaction at 230 to 260 °C for 30 min was found to optimize fuel properties of the torrefied rice husk.
  • Researchpp 5906-5916Gao, Z., Di, M., Zhang, X., and Zhang, D. (2014). "Effects of alkali treatment and polyisocyanate crosslinking on the mechanical properties of kraft fiber-reinforced unsaturated polyester composites," BioRes. 9(4), 5906-5916.AbstractPDF
    The effects of alkali treatment and polyisocyanate crosslinking on the mechanical properties of kraft fiber-reinforced UPE composites were investigated by means of tensile evaluation, SEM analysis, and XRD analysis. The results indicated that the alkali treatment decreased the tensile strength of the prepared composite before aging from 121 MPa to 97 MPa due to the decreased degree of crystallinity of the alkali-treated kraft fiber. Polyisocyanate crosslinking could apparently improve the mechanical properties and stability in terms of a 43% increase of non-aged tensile strength and 52% increase of hydrothermal-aged tensile strength compared with the controlled composite without crosslinking modification, which was attributable to the formation of strong chemical bonding between the interfaces of kraft fiber and polyester.
  • Researchpp 5917-5927Chen, Z., Li, C., Song, Z., and Qian, X. (2014). "Modification of precipitated calcium carbonate filler for papermaking with adsorption of cationically derivatized chitosan and carboxymethyl chitosan," BioRes. 9(4), 5917-5927.AbstractPDF
    To improve the performance of precipitated calcium carbonate (PCC) as a papermaking filler, the combination of cationically derivatized chitosan and carboxymethyl chitosan was employed as modification agents for PCC. When the dosage ratio of cationic chitosan to carboxymethyl chitosan was 1:2, the two polymers were efficiently deposited onto precipitated calcium carbonate, which showed better retention than the control PCC at the same dosage. The brightness and opacity of handsheets filled with modified precipitated calcium carbonate were markedly improved in comparison to the control. Furthermore, handsheets filled with modified precipitated calcium carbonate reduced the loss of tensile strength compared to the control at the same precipitated calcium carbonate content.
  • Researchpp 5928-5939Miao, X., Chen, H., Lang, Q., Bi, Z., Zheng, X., and Pu, J. (2014). "Characterization of Ailanthus altissima veneer modified by urea-formaldehyde pre-polymer with compression drying," BioRes. 9(4), 5928-5939.AbstractPDF
    Recently, Ailanthus altissima wood has received increased attention in China. Although Ailanthus altissima has a number of advantages, such as fast-growing character and high density, the low dimensional stability is a restraining factor. Chemical modification could be a feasible way to overcome such drawbacks. The aim of this research was to study the physical and chemical properties of Ailanthus altissima veneers treated by urea-formaldehyde pre-polymer impregnation and compression drying. The results showed that this approach not only significantly increased the dimensional stability of wood, but also enhanced the bending strength and compressive strength parallel to the grain. The FT-IR analysis showed that the intensity of hydroxyl (-OH) and carbonyl (C=O) absorption peaks decreased, which indicated that the NH-CH2-OH of the pre-polymer reacted with the wood’s carboxyl and hydroxyl groups. The positions of the XRD peaks did not change, which indicated that the structure of cellulose crystallinity was not noticeably affected by the chemical modification. The TGA showed that the thermal stability of modified wood was improved , while FESEM showed that the wood cell wall and vessels were impregnated with chemicals.
  • Researchpp 5940-5950Huang, C., Zhu, Q., Li, C., Lin, W., and Xue, D. (2014). "Effects of micronized fibers on the cushion properties of foam buffer package materials," BioRes. 9(4), 5940-5950.AbstractPDF
    Foam buffer package materials composed of plant fibers have been a focus of research in recent years because of their environmentally beneficial ability to become fully disintegrated. In this study, bleached bagasse pulp was micronized using a PFI mill, and foam buffer materials were prepared using the micronized fiber. The effects of the beating degree of micronized fibers on the dimensional stability, moisture absorption, static compression, and dynamic compression characteristics were discussed. Results showed that, in both the static and the dynamic compression experiments, the buffer properties improved with an increasing beating degree. The buffer materials made of highly micronized fiber were stronger under pressure and impact. Specifically, the highly micronized fiber’s ability to absorb energy curing impact was improved, demonstrating that it can support a higher compression and impacting load in a certain deformation scope. However, during the drying process, the dimensional stability of the samples also declined with an increasing beating degree. The moisture absorption of the samples improved when the beating degree was increased.
  • Researchpp 5951-5962Hu, D., Wang, P., Li, J., and Wang, L. (2014). "Functionalization of microcrystalline cellulose with N,N-dimethyldodecylamine for the removal of Congo Red dye from an aqueous solution," BioRes. 9(4), 5951-5962.AbstractPDF
    Microcrystalline cellulose (MCC) was functionalized with quaternary amine groups for use as an adsorbent to remove Congo Red dye (CR) from aqueous solution. The ultrasonic pretreatment of MCC was investigated during its functionalization. Characterization was conducted using infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The batch adsorption of the functionalized MCC was studied to evaluate the effects of dye concentration, pH of solution, temperature, and NaCl concentration on the adsorption CR. The adsorbent (FM-1) obtained using ultrasonic pretreatment of MCC under 10.8 kJ•g-1 exhibited an adsorption capacity of 304 mg•g-1 at initial pH under a dose of 0.1 g•L-1 and initial concentration of 80 mg•L-1. After functionalization, the FT-IR and XPS results indicated that the quaternary amine group was successfully grafted onto the cellulose, the surface was transformed to be coarse and porous, and the crystalline structure of the original cellulose was disrupted. FM-1 has been shown to be a promising and efficient adsorbent for the removal of CR from an aqueous solution.
  • Researchpp 5963-5975Barcík, Š., Gašparík, M., Horejš, P. (2014). "Influence of thermal modification on nail withdrawal strength of spruce wood," BioRes. 9(4), 5963-5975.AbstractPDF
    This paper deals with nail withdrawal strength of spruce (Picea abies L.) with a focus on its dependence on thermal modification. Nail withdrawal strength is a feature of wood that is very important in the construction of wooden buildings. There are many studies dealing with the nail withdrawal strength of natural wood; however, this feature is much less explored with respect to thermally modified wood. Spruce wood was thermally modified at three different temperatures (140, 180, and 240 °C), and the nail withdrawal strength was evaluated for three types of nails driven into three anatomical directions. Values of nail withdrawal strength of thermally modified wood were compared with values of control spruce wood. The effect of thermal modification was clear: with increasing temperature, gradually decreasing values ​​of nail withdrawal strength were obtained. The highest values ​​were found in the tangential direction, and the lowest occurred in the axial direction. Annularly threaded nails had the highest values of nail withdrawal strength, while helically threaded nails had the lowest results.
  • Researchpp 5976-5987Peng, Y., He, B., Zhao, L., and Zhao, G. (2014). "Effect of pre-flocculation of lime mud CaCO3 filler on AKD sizing efficiency," BioRes. 9(4), 5976-5987.AbstractPDF
    Lime mud (LM), whose main component is calcium carbonate, is a by-product in the pulp and papermaking industry. For non-wood pulping processes, large amounts of LM are produced every year, and a portion of them has been used as a paper filler. However, LM significantly lowers alkyl ketene dimer (AKD) sizing efficiency when added to paper. In this study, LM slurry was first pre-flocculated using some commonly used wet-end additives; then, the pre-flocculated LM was added to the pulp for handsheet preparation. The effect of LM pre-flocculation on AKD sizing efficiency was investigated by means of Cobb60 value, contact angle, and sizing reversion. Finally, the AKD adsorption, particle size, BET surface area, BJH pore volume, and zeta potential of native and pre-flocculated LM were measured. It was found that handsheets filled with pre-flocculated LM had lower Cobb60 values and larger contact angles compared to handsheets filled with native LM. The sizing reversion was also alleviated to a certain extent. This was probably because the BET surface area and BJH pore volume of pre-flocculated LM were lower than native LM and the zeta potential was higher than native LM, which led to a much less adsorption of AKD. Thus, AKD sizing efficiency was significantly improved.
  • Researchpp 5988-6001Weerasai, K., Suriyachai, N., Poonsrisawat, A., Arnthong, J., Unrean, P., Laosiripojana, N., and Champreda, V. (2014). "Sequential acid and alkaline pretreatment of rice straw for bioethanol fermentation," BioRes. 9(4), 5988-6001.AbstractPDF
    Pretreatment is a prerequisite step for increasing the enzymatic digestibility of agricultural residues for conversion to fuels and chemicals in biorefineries. In this study, a sequential acid and alkaline process was developed for pretreatment of rice straw for ethanol fermentation. Effects of key parameters in acid pretreatment were studied using a full factorial design model, which showed the higher influence of time compared to acid concentration and temperature on reducing sugar yields. The combined sequential process involved an initial hemicellulose solubilization by dilute acid using 1% (w/v) H2SO4 at 125 °C for 10 min, followed by alkaline delignification using 1.25% NaOH at 90 °C for 10 min. Under these conditions, a glucose recovery yield of 70.9% from saccharification of the cellulose enriched fraction was obtained with 2- to 4-fold savings in chemical usage as compared with single-step processes. Scanning electron microscopy revealed modification of biomass micro-structure and increases in reactive surface area. Simultaneous saccharification and fermentation of the solid residues by Saccharomyces cerevisiae, using 25 FPU/g Accellerase® 1500, led to a final ethanol concentration of 21.0 g/L with the productivity of 0.27 g/L/h, equivalent to 84.6% theoretical yield. The results indicate the potential of the sequential process for increasing pretreatment efficiency and allowing stepwise separation of lignocellulose components for multi-product biorefineries.
  • Researchpp 6002-6018Bylin, S., Wells, T., Sun, Q., Ragauskas, A., and Theliander, H. (2014). "Lignin structure and aggregation behavior in a two-component ionic liquid solvent system," BioRes. 9(4), 6002-6018.AbstractPDF
    Ionic liquids are of potential interest in the processing of lignocellulosic biomass. In this study, the ionic liquid co-solvent system of 1-methylimidazole (MIM) and 1-ethyl-3-methyl-imidazolium acetate (EMIMAc) was used to solvate LignoBoost lignin fractionated from black liquor obtained from a kraft paper mill. Lignin ethanol-precipitated (LEP) and ethanol-soluble (LES) fractions were characterized via gel permeation chromatography (GPC) and 13C- and 31P-nuclear magnetic resonance spectroscopy (NMR) to determine structural characteristics and their relationship to polymer solubility in the system. Polymer integrity and solubility were optimal at ~20% lignin loading (w/w). Results showed that LEPs were generally of higher apparent molecular weight (Mw) and enriched with condensed/aliphatic ether linkages and aliphatic hydroxyls. The LESs had a lower apparent Mw and were enriched with carboxylic and phenolic groups. This newly gained knowledge on lignin fractionation and aggregation in the present solvent system provides future opportunities for tuning fractionation/extraction to suit a specific biomass-derived product, e.g., carbon fibers.
  • Researchpp 6019-6027Li, H., Zhang, H., Li, J., and Du, F. (2014). "Comparison of interfiber bonding ability of different poplar P-RC alkaline peroxide mechanical pulp (APMP) fiber fractions," BioRes. 9(4), 6019-6027.AbstractPDF
    In recent years, the alkaline peroxide mechanical pulping performed with refiner-chemical preconditioning (P-RC APMP) has obtained a wide application in many paper grades in China. This is due to such desirable pulp characteristics as its high bulk, opacity, and light scattering coefficient. However, compared with its bleached chemical pulps, the poplar P-RC APMP has weak bonding strength, which limits its application in value-added products. Usually, the interfiber bonding abilities of different fiber fractions are quite different. In this study, the page bonding strength index (B) and the interfiber bonding abilities (shear bond strength per unit area (b) and relative bonding area (RBA)) of different P-RC APMP fiber fractions were extrapolated by the traditional Page Equation. The results show that the higher B could be obtained when the fiber fraction was shorter or smaller. The same trend was observed for b and RBA. Wet pressing was used to improve the bonding ability, and higher pressure of wet pressing or shorter fiber fraction can lead to obviously higher tensile strength.
  • Researchpp 6028-6040Dong, Y., Yan, Y., Zhang, S., and Li, J. (2014). "Wood/polymer nanocomposites prepared by impregnation with furfuryl alcohol and nano-SiO2," BioRes. 9(4), 6028-6040.AbstractPDF
    Wood/polymer nanocomposites were prepared by vacuum impregnation of furfuryl alcohol (FA) and nano-SiO2 into fast-growing poplar wood. The nano-SiO2 was mixed with FA solution, followed by in-situ polymerization of FA. The properties of nanocomposites and the effects of nanoparticles on these properties were investigated. Wood physico-mechanical properties, such as dimensional stability, density, water uptake, and surface hardness, were significantly improved. Moreover, the addition of nano-SiO2 improved the surface hardness and dimensional stability of wood and kept the excellent properties of FA-treated wood. Thermogravimetric analysis indicated that the effect of nano-SiO2 on thermostability was hindered. X-ray photoelectron spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy showed that nano-SiO2 was successfully incorporated into wood via the action of FA, and diffused into the wood lumen and cell wall. X-ray diffraction results indicated the weakening of the crystallinity in the treated wood was due to the polymerization of FA.
  • Researchpp 6041-6072Kautto, J., Realff, M. J., Ragauskas, A. J., and Kässi, T. (2014). "Economic analysis of an organosolv process for bioethanol production," BioRes. 9(4), 6041-6072.AbstractPDF
    In a previous paper, conceptual process design, simulation, and mass and energy balances were presented for an organosolv process with a hardwood feed of 2350 metric tons (MT) per day and ethanol, lignin, furfural, and acetic acid production rates of 459, 310, 6.6, and 30.3 MT/day, respectively. In this paper, the investment and operating costs of the process and the minimum ethanol selling price (MESP) to make the process economically feasible were estimated. The total capital investment of the plant was approximately 720 million USD. Lignin price was found to affect the MESP considerably. With a base case lignin price of 450 USD/MT, the MESP was approximately 3.1 USD per gallon (gal). Higher lignin price of 1000 USD/MT was required to equal the MESP with the December 2013 ethanol market price (2.0 USD/gal). In addition to lignin price, the MESP was found to be strongly affected by feedstock, enzyme, and investment costs. Variations in feedstock and investment costs affected the MESP by approximately 0.2 and 0.5 USD/gal, respectively. Changing the enzyme dosage and price from base case estimate of 5270 USD/MT and 0.02 g/g cellulose to more conservative 3700 USD/MT and 0.06 g/g cellulose, respectively, increased the MESP by 0.59 USD/gal.
  • Researchpp 6073-6086Lao, W., Li, G., Zhou, Q., and Qin, T. (2014). "Quantitative analysis of biomass in three types of wood-plastic composites by FTIR spectroscopy," BioRes. 9(4), 6073-6086.AbstractPDF
    Biomass content greatly affects the properties of wood-plastic composites (WPCs). Determination of the biomass in WPCs is important for the development of WPCs. In this study, transmission Fourier transform infrared (FTIR) spectroscopy was used for biomass quantification in the following WPCs: Moso bamboo/polypropylene (PP) composites, Chinese fir/PP composites, and poplar/PP composites. The bands in the region of 1060 to 1030 cm-1 were considered characteristic of biomass. The peak at 1377 cm-1 was typical of PP. The peak intensities ratios (PIRs) of biomass to PP were determined, and the biomass contents were plotted against the PIRs. The achieved coefficients of determination (R2) of the calibration fits exceeded 0.96. The results of validation showed that the range of the relative prediction deviations for biomass within WPC species was lower than ± 5.0%. Additionally, all three WPC species were combined into one data set, and a mixed model was constructed that had a slight decrease in the quality of the correlation (R2 = 0.93). The range of the relative prediction deviations for biomass between WPC species did not exceed ± 9.0%.
  • Researchpp 6087-6099Wei, W., Song, W., and Zhang, S. (2014). "Preparation and characterization of hydroxyapatite-poly(vinyl alcohol) composites reinforced with cellulose nanocrystals," BioRes. 9(4), 6087-6099.AbstractPDF
    Hydroxyapatite/poly(vinyl alcohol) (Hap/PVA) composites have been proposed as a promising biomaterial for use in articular cartilage repair. In this study, HAp/PVA composite gels reinforced with cellulose nanocrystals (CNC) were prepared using the freeze/thaw method. The influence of CNC as a reinforcement on the structure of composite gels was investigated via Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The mechanical properties and thermal stability of the composite gels were also studied. The FT-IR and XRD results indicated that the HAp/PVA/CNC composite gels were formed by hydrogen bonding. SEM morphology showed that the CNC served as an enhancement phase that interpenetrated the network of the HAp/PVA composite gels. The tensile strength and tensile modulus of the composites improved with increasing dosage of CNC. The thermal stability measurements indicated that the thermal stability of the HAp/PVA composites was slightly improved with the addition of the CNC.
  • Researchpp 6100-6116Ungurean, M., Csanádi, Z., Gubicza, L., and Péter, F. (2014). "An integrated process of ionic liquid pretreatment and enzymatic hydrolysis of lignocellulosic biomass with immobilised cellulase," BioRes. 9(4), 6100-6116.AbstractPDF
    An integrated process of lignocellulosic biomass conversion was set up involving pretreatment by an ionic liquid (IL) and hydrolysis of cellulose using cellulase immobilised by the sol-gel method, with recovery and reuse of both the IL and biocatalyst. As all investigated ILs, regardless of the nature of the anion and the cation, led to the loss of at least 50% of the hydrolytic activity of cellulase, the preferred solution involved reprecipitation of cellulose and lignin after the pretreatment, instead of performing the enzymatic hydrolysis in the same reaction system. The cellulose recovered after pretreatment with 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]) and dimethylsulfoxide (DMSO) (1:1 ratio, v/v) was hydrolysed with almost double yield after 8 h of reaction time with the immobilised cellulase, compared to the reference microcrystalline cellulose. The dissolution capacity of the pretreatment mixture was maintained at satisfactory level during five reuse cycles. The immobilised cellulase was recycled in nine reaction cycles, preserving about 30% of the initial activity.
  • Researchpp 6117-6129Qiao, Z., Gu, J., Zuo, Y., Tan, H., and Zhang, Y. (2014). "The effect of carboxymethyl cellulose addition on the properties of starch-based wood adhesive," BioRes. 9(4), 6117-6129.AbstractPDF
    Starch adhesive was prepared utilizing corn starch, polyvinyl alcohol, and borax as raw materials. A certain amount of water-soluble carboxymethyl cellulose (CMC) was added in the preparation process, and a certain percentage of polymethylene polyphenylene isocyanate pre-polymer as cross-linking agent was used to improve its water resistance. To evaluate the water resistance, three-layer plywood was fabricated by hot pressing, and bonding strength was measured using a mechanical testing machine according to the National Standard of the People’s Republic of China GB/T 17657-2013. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to characterize curing of the adhesion. The results showed that the initial viscosity, solids content, and bonding strength of the starch adhesive, as well as the interface compatibility between starch adhesive and pre-polymer, were all improved. The curing temperature of the adhesive decreased, and the optimal addition of CMC was 0.375%.
  • Researchpp 6130-6140Zhang, B., Wang, L., Hasan, R., and Shahbazi, A. (2014). "Characterization of a native algae species Chlamydonmonas debaryana: Strain selection, bioremediation ability, and lipid characterization," BioRes. 9(4), 6130-6140.AbstractPDF
    Native microalgal species may offer a favorable combination of both wastewater treatment and biofuel production. In this research, a green microalgae, Chlamydomonas debaryana, was isolated from a local lagoon, screened for its lipid content using flow cytometry, and further identified with microscopic observations and DNA sequence analysis. When using swine wastewater as a medium, the biomass yields were between 0.6 and 1.62 g/L, giving a median value of 1.11 g/L. By increasing mass transfer rates and providing sufficient light intensity, the microalgal growth was intrinsically enhanced. The growth of C. debaryana reduced most nutritional contents of the wastewater except iron. When combining the microalgal growth and nutrient removal, C. debaryana was able to utilize 1.3 to 1.6×103 mg COD (chemical oxygen demand)/g biomass, 55 to 90 ppm ammonia/g biomass, and 48 to 89 ppm phosphorous/g biomass, The lipid content of C. debaryana was 19.9 ± 4.3% of cell dry weight. The transesterified microalgal oil mostly consisted of 14 kinds of fatty acids, ranging from C5 to C22, which can be refined into renewable jet fuel or used as sources of omega-3 and omega-6 fatty acids.
  • Researchpp 6141-6152Hu, Y., and Yu, W. (2014). "Effects of acid dye on the performance of bamboo-based fiber composites," BioRes. 9(4), 6141-6152.AbstractPDF
    The objective of this study was to investigate the influence of acid dye on color change, modulus of rupture, modulus of elasticity, shear strength (parallel loading), thickness swelling rate, and water absorption rate of bamboo-based fiber composites from Phyllostachys pubescens. Bamboo fiber veneers were treated with acid black via three procedures: dyed in water at 20 °C, dyed in water at 90 °C, and dyed in ethanol at 75 °C. The samples dyed in ethanol at 75 °C and those dyed in water at 90 °C had a higher exhaustion rate than those dyed in water at 20 °C. The color change of bamboo fiber veneers exhibited similar variation trends by the three methods. The dyeing procedure slightly reduced the modulus of rupture and modulus of elasticity of bamboo-based fiber composites. Compared with the samples dyed in water, the samples dyed in ethanol had reduced shear strength (parallel loading) and modulus of elasticity. The thickness swelling rate and water absorption rate of bamboo-based fiber composite samples were reduced by the dye treatment.
  • Researchpp 6153-6165Mushtaq, M., Sultana, B., Bhatti, H. N., and Asgher, M. (2014). "Optimization of enzyme-assisted revalorization of sweet lime (Citrus limetta Risso) peel into phenolic antioxidants," BioRes. 9(4), 6153-6165.AbstractPDF
    Enzymatic treatment was used to induce liberation of antioxidant phenolics from under-utilized sweet lime peel (CLP). Small rotatable central composite design (SRCCD) was selected to optimize the conditions of enzymatic processing, i.e., enzyme concentration (2 to 5%), pH (5 to 8), temperature (30 to 75 °C), and incubation time (30 to 120 min). The morphological characterization of enzymatically hydrolyzed CLP was performed using field emission scanning electron microscopy (FESEM). Extracts obtained under suitable conditions were characterized for their phenolic profile by use of reverse-phase high-performance liquid chromatography coupled with a diode array detector (RP-HPLC-DAD) and evaluated for in vitro antioxidant activities. The observed results revealed that optimum enzymatic pre-treatment doubled the recovery of phenolic antioxidants with maximum Trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging potential (IC50). The observed results indicate that enzyme-assisted extraction might be a green choice to revalorize agro-processing residues.
  • Researchpp 6166-6192Olugbenga, O., Labunmi, L., and Bodunde, O. (2014). "Microcrystalline cellulose from plant wastes through sodium hydroxide-anthraquinone-ethanol pulping," BioRes. 9(4), 6166-6192.AbstractPDF
    Microcrystalline cellulose was prepared from wastes of Tithonia diversifolia, inflorescence stems of Musa sapientum, and Musa paradisiaca by soda-anthraquinone–ethanol pulping method. They were bleached by sodium chlorite and then alpha-cellulose was isolated, followed by preparation of microcrystalline cellulose. The study revealed the effect of various processing stages on the properties of the cellulose obtained. Yields of more than 80% of microcrystalline cellulose were obtained. Fourier transform infrared (FTIR) and solid state 13C Nuclear magnetic resonance (13C NMR) confirmed the presence of the major expected peaks in microcrystalline cellulose. Scanning electron microscopy (SEM) revealed that Musa species had short fiber length and mixtures of non-aggregated spherical, rod-shaped and thread like microcrystalline cellulose, but Tithonia diversifolia had aggregate crystal packed formation. The results compared well with those of other authors and were able to meet most of the requirements specified in British Pharmacopoeia. The study revealed that a drug excipient like microcrystalline cellulose that could protect thermo-labile active ingredients could be successfully obtained from abundant non-woody agricultural wastes.
  • Researchpp 6193-6204Chi, C., Liu, M., Jameel, H., Zhang, S., and Zhang, Z. (2014). "Hydrothermal pretreatment of hardwood chips prior to alkaline pulping and D0(Ep)D1 bleaching," BioRes. 9(4), 6193-6204.AbstractPDF
    In this study, mixed southern hardwood was pretreated via a hydrothermal process at 160 °C for 1 h. Alkaline pulping was then conducted on both the pretreated and original chips to prepare pulp with Kappa 17 and 30. For the Kappa 30 pulps, oxygen delignification was further carried out to render Kappa 17. After pulping, the different pulps with similar Kappa 17 were bleached by the D0(EP)D1 sequence. Pulping results show that the pretreated chips are easier to cook and necessitate less alkaline charge to achieve a similar Kappa without decreasing the pulp viscosity. Under similar bleaching conditions, hydrothermal pretreatment leads to pulps with a higher brightness, viscosity, and paper sheet opacity and scattering coefficient, while also lowering the burst and tensile strength. Furthermore, the pulp fiber length, fiber width, and percentage of fines decreases, yet the coarseness, curl index, and kink index increase. However, the paper properties of bleached pulps are not improved significantly when subjected to modified continuous cooking (MCC) pulping or oxygen delignification.
  • Researchpp 6205-6213Wang, L., Zhang, X., Xu, G., Xu, H., and Wu, J. (2014). "Using lignin content, cellulose content, and cellulose crystallinity as indicators of wood decay in Juglans mandshurica Maxim. and Pinus koraiensis," BioRes. 9(4), 6205-6213.AbstractPDF
    The main chemical indicators for healthy wood and rotted wood at different decay levels in two species, namely Juglans mandshurica Maxim. and Pinus koraiensis, were preliminary analyzed. The cellulose content, lignin content, and relative crystallinity were measured using the nitric acid-ethanol method, acid-insoluble lignin, and X-ray diffraction to further explore the process of wood decay. Results indicated that the cellulose content and relative crystallinity decreased and the acid-insoluble lignin content increased as wood decay increased. X-ray diffraction results showed that there were no significant changes in the lattice structure between healthy wood and rotted wood. Approximately 98.3% and 99.9% of the variations in wood decay for Juglans mandshurica Maxim. and Pinus koraiensis, respectively, can be explained by the comprehensive effect of the above chemical indicators.
  • Researchpp 6214-6226Licht, J., McLaughlin, H., Burns, C., and Shields, F. (2014). "Can biochar come to the rescue of coastal barren species? A controlled study reports on the impact of biochar amendment on their survival," BioRes. 9(4), 6214-6226.AbstractPDF
    Indigenous species in coastal barren communities are subject to anthropogenic and environmental pressures; some species are in decline, and there is uncertainty about their long-term survival. The authors added supplemental soil carbon in the form of red oak biochar to calcined clay (1:9) to determine the effect of this treatment on survival of legume (Lupinus perennis and Baptisia tinctoria) and non-legume (Vaccinium angustifolium and Quercus ilicifolia) species during a period spanning two and a half seasons of unirrigated pot tests. Red oak biochar used in the experiment was produced from pyrolysis, the thermochemical devolitization and carbonization of the starting biomass. Biochar significantly affected the survival rates of all species (P=<.03). Biochar-treated non-legumes had higher survival rates (P=<.10) than similarly treated legumes. Future investigations of biochars, particularly those evolved from recycled lignocellulosic wastes, associated with survival, should focus on reversal of habitat loss.
  • Researchpp 6227-6240Arenas, J. P., Rebolledo, J., del Rey, R., and Alba, J. (2014). "Sound absorption properties of unbleached cellulose loose-fill insulation material," BioRes. 9(4), 6227-6240.AbstractPDF
    Recyclable cellulose loose-fill insulation has been commonly used in heavy timber construction for treating attic areas, under floors, and wall cavities. Through the kraft process, the unbleached cellulose adopts a texture characterized by small crumbs, forming a porous medium. In this work, different samples of a single layer of loose-fill cellulose insulation with different thicknesses were tested to measure their sound absorption properties, the airflow resistivity, and porosity for both dry and moist samples. The regression coefficients for an empirical model were calculated using a numerical optimization method. It is concluded that the model predicts the acoustical performance of this material well and that the sound absorption properties of the material are similar to those of mineral fiber-based materials.
  • Researchpp 6241-6253Chen, D., Zhou, J., Zhang, Q., Zhu, X., and Lu, Q. (2014). "Torrefaction of rice husk using TG-FTIR and its effect on the fuel characteristics, carbon, and energy yields," BioRes. 9(4), 6241-6253.AbstractPDF
    A torrefaction testing method using TG-FTIR is presented, ensuring accuracy of torrefaction temperature and time. Torrefaction experiments of rice husk were performed at different temperatures (200, 230, 260, and 290 °C) for 30 min. The effect of torrefaction on the fuel characteristics was studied. Yields of carbon and oxygen, as well as solid and energy, were also considered. TG-FTIR analysis showed that in the depolymerization stage of the torrefaction process, CO2 characteristic peaks appeared, while those of carbonyl compounds and aromatic hydrocarbons were weaker. In the devolatilization stage, the characteristic peaks of CO2 and H2O were significant. Meanwhile, carbonyl compounds, aromatic hydrocarbons, and phenols were gradually produced. After that, each absorption peak gradually became weaker. After torrefaction at 290 °C, more than 76.6% of energy was retained in torrefied rice husk, while the solid yield was only 65.6%. 1.8%~52.2% of oxygen in rice husk was released in the torrefaction temperature range of 200 °C to 290 °C. Torrefaction increased the heating value, reduced the oxygen content, and improved the storability, which indicates that torrefaction is an effective way to improve the properties of rice husk.
  • Researchpp 6254-6266Seo, Y. B., Lee, Y. H., and Chung, J. K. (2014). "The improvement of recycled newsprint properties by in-situ CaCO3 loading," BioRes. 9(4), 6254-6266.AbstractPDF
    In-situ CaCO3 loading of old newspaper (ONP) fiber furnish was studied as a method to improve the properties of recycled newsprint paper. The effects of in-situ loading on the morphological and physical properties of ONP furnish were examined comparatively with conventional loading methods (addition of ground or precipitated CaCO3, without and with pre-flocculation treatment). The effective residual ink content (ERIC) and macro sticky content began to decrease as soon as the in-situ CaCO3 formation started by the injection of carbon dioxide to the reaction tank, where the ONP furnish and calcium oxide mixture was agitated in high shear. When the reaction finished at pH 7, there were no more decreases of ERIC value and sticky content. Improvement of first pass retention and brightness was significant for the in-situ CaCO3 loading method. The decrease in breaking length with the addition of CaCO3 in the in-situ formation method was equivalent to or slightly lower than that of the CaCO3 pre-flocculation method, which is a method well known to give higher strength properties. Optical images from the FlowCAM® dynamic imaging particle analyzer showed strongly attached organic (fines) and inorganic (CaCO3) materials in the in-situ CaCO3 loading method.
  • Researchpp 6267-6276Zhang, J., Chen, H., Pizzi, A., Li, Y., Gao, Q., and Li, J. (2014). "Characterization and application of urea-formaldehyde-furfural co-condensed resins as wood adhesives," BioRes. 9(4), 6267-6276.AbstractPDF
    Furfural, as an organic compound derived from biomass materials, was used to partially substitute for formaldehyde in the synthesis of UF resin. Urea-formaldehyde-furfural co-condensed (UFFR) resins with different substitute ratios of furfural to formaldehyde (FR/F) were prepared. The effects of the FR/F substitute ratio on the performances of UFFR resins were investigated. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) and Fourier transform infrared spectroscopy (FT-IR) were applied to characterize the chemical structures of UFFR resins. Plywood bonded by these resins was manufactured, and its bond strength and formaldehyde emission were measured. The results showed that the substitution of furfural in place of formaldehyde could reduce the free formaldehyde content effectively at the expense of prolongation of the curing time. The spectra of MALDI-TOF and FTIR confirmed the co-condensation of urea-formaldehyde-furfural both in uncured and cured resins. Plywood prepared under optimized parameters could yield high bond strength and low formaldehyde emission, which were 0.84 MPa and 0.23 ppm, respectively. The optimized parameters were as follows: a FR/F substitute ratio of 1/3; 1% (NH4)2S2O8 as the curing agent; and a hot pressing temperature of 130 °C. Hence, it is feasible to substitute partially formaldehyde by furfural to prepare UFFR resins as wood adhesives for plywood.
  • Researchpp 6277-6289Li, X.-H., and Wu, S. B. (2014). "Chemical structure and pyrolysis characteristics of the soda-alkali lignin fractions," BioRes. 9(4), 6277-6289.AbstractPDF
    In the present work, three different kinds of lignin fractions (L1, L2, and L3) were isolated from the alkali black liquor of Cunninghamia lanceolata by selective precipitation at the pH values of 8 (fraction L1), 5 (fraction L2), and 2 (fraction L3). Elemental analysis, gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), 31P nuclear magnetic resonance (31P-NMR), thermal gravimetric analysis (TG), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) were used to characterize the chemical structure and thermochemical properties of the three lignin fractions. The results showed that L1 presented higher heating value (HHV) and molecular weight compared with L2 and L3. The structures and functional group types were similar for the three lignin grades. However, there was more hydroxyl group in L1 than that in L2 and L3, and the L3 contained a higher amount of carboxylic hydroxyl. L1 exhibited the lowest weight loss value (47.8%) at 200 to 600 oC and the highest amount of charred residue (45.1%), which was exactly the opposite for L3. Phenols, the dominant pyrolysis products, constituted 92.17% of all the pyrolysis products for L1, 93.93% for L2, and 88.09% for L3.
  • Researchpp 6290-6303Tian, J., Ren, S., Fang, G., Ma, Y., and Ai, Q. (2014). "Preparation and performance of dimethyl-acetoxy-(2-carboxymethyl ether)-lignin ammonium chloride amphoteric surfactant," BioRes. 9(4), 6290-6303.AbstractPDF
    To improve the added value of the lignin products, dimethyl-acetoxy-(2-carboxymethyl ether)-lignin ammonium chloride (DALAC) amphoteric surfactant was synthesized from wheat straw alkali lignin raw material. The structure was analyzed by Fourier transform infrared spectroscopy (FT-IR), and the solubility in different pH solutions was evaluated. The effect of DALAC on adsorption performance was investigated with a solution of copper ions as simulated wastewater, while its flocculation performance was investigated with acid black ATT and methylene blue (MB) wastewater as simulate dyes. The results showed that carboxyl and quaternary amine groups were successfully grafted, and nitrogen content of DALAC was 3.66%. The adsorption isotherm of copper ions with DALAC fit the Freundlich equation. Optimum adsorption conditions for Cu2+ were dosage 0.1 g/L, pH 5.5, and adsorption time 6 h, for which the maximum adsorption capacity was 399 mg/g. The maximum removal rate of Acid black ATT (anionic dye) was 97.8% when the optimum flocculation conditions were dosage 4 g/L, pH 2, and mass concentration of dye 0.1 g/L. The maximum removal rate of methylene blue (cationic dye) was 98.7 %, when the optimum flocculation conditions were dosage 2.5 g/L, pH 9, and mass concentration of dye 0.1 g/L. DALAC will be expected to a novel adsorbent of heavy metal ion and flocculants of dyes in the future.
  • Researchpp 6304-6315Deng, Y., Guo, Y., Qian, Y., Lou, H., and Qiu, X. (2014). "Effect of temperature on a lignin-based polymer with two types of microstructures," BioRes. 9(4), 6304-6315.AbstractPDF
    A lignin-based polymer (GCL1-JB) was dispersed in solvents with different proportion between 1,4 dioxane and water for forming linear and spherical microstructures. The effects of temperature on the solution behaviors and adsorption characteristics of GCL1-JB with different microstructures were investigated by light scattering, conductivity, zeta potential, UV-Vis spectroscopy, atomic force microscopy (AFM), and contact angle measurements. Results showed that GCL1-JB solutions with different microstructures have different responses to environmental temperature changes, which is related to the movements of charges. For GCL1-JB with a spherical microstructure, as the temperature increases, the degree of ionization does not decrease. However, the surface charges decrease due to the charged groups moving from the surface into the interior because of the charge gradient, which induces a significant decrease in the zeta potential. As the surface charges decrease and the hydrophobic interaction increases, the GCL1-JB aggregates. Therefore, the scattered light intensity increases significantly and the corresponding GCL1-JB adsorbed film has a larger adsorbed amount, a more rough surface , and a larger contact angle. However, for GCL1-JB with a linear microstructure, the surface charges do not obviously change with a temperature increase, even though the charged groups move from side to side. Therefore, the zeta potential and the scattered light intensities of these GCL1-JB solutions are basically independent of temperature, and the corresponding adsorption characteristics do not obviously change.
  • Researchpp 6316-6328Xia, X., Sun, Y., Wu, K., and Jiang, Q. (2014). "Modeling of a straw ring-die briquetting process," BioRes. 9(4), 6316-6328.AbstractPDF
    Efficient utilization of biomass resources is crucial for providing renewable energy and mitigating the risk of environmental pollution caused by crop straw burning in China. Straw ring-die briquetting forming is a convenient densification technology to make the low density biomass into briquette fuel; however, the energy consumption of this process is still a challenge. Productivity and torque modeling were carried out in this study on the basis of theoretical derivation. Generally, the straw briquetting process is divided into a compression deformation stage and an extrusion forming stage with the die structure (ring die and roller radius ratio λ) and friction angle φ being the main factors that affect the productivity. Mechanical modeling based on material compaction and calculation modeling based on die-hole pressure were considered for the calculation of σαx in the torque model. A calculation case was then conducted according to the theoretical model, and actual productivity and torque testing were performed for validation purposes. Results show that this deduced productivity model is successful because the deviation is 4.61%. The torque model determined by the calculation model based on die-hole pressure had a better accuracy with a deviation of 6.76%.
  • Researchpp 6329-6339Mirski, R., Dziurka, D., Dukarska, D., Czarnecki, R., and Cofta, G. (2014). "The influence of microfungi on physicomechanical properties of particleboards," BioRes. 9(4), 6329-6339.AbstractPDF
    This study concerns the influence of selected fungi on changes in physical and mechanical properties of type P2 particleboards intended for use in dry conditions. The tested fungi included Aspergillus niger van Tiehgem, Chaetomium globosum Kunze et Fr., Trichoderma viride Persoonex S.F., Gray aggr., and Penicillium funiculosum Thom. The incubation process lasted for 16 weeks, yet samples for the strength test were selected after a period of four weeks. The degradation level of boards was estimated by measuring the decrement of initial mass and changes in physicomechanical properties. The obtained results showed that mechanical strength of the investigated boards affected by the tested fungi decreased by 15% to 20%. However, the differences in DSC thermographs indicate that it is cellulose that mainly undergoes degradation in the wood of the investigated boards. Based on the changes in mechanical properties and DSC analyses, we consider T. viride and A. niger as the most aggressive fungal species.
  • Researchpp 6340-6349Yuksel, M., Yildirim, N., Kasal, A., Erdil, Y. Z., and Demirci, S. (2014). "Effect of the panel type and panel thickness on moment resistance of screw-jointed corner joints and stiffness of four-member cabinets," BioRes. 9(4), 6340-6349.AbstractPDF
    The objective of this study was to investigate the effects of panel type and panel thickness on moment resistance of L-type corner joints and deflection characteristics of four-member cabinets. Three different wood based panels, namely particleboard (PB), medium density fiberboard (MDF), and okoume (Aucoumea klaineana) plywood (PW) were utilized in two different thickness levels for constructing the four-member cabinets. All corner joints and cases were assembled with 4 x 50 mm screws without adhesive. The four member cabinets were tested under static load by supporting at three points. Furthermore, moment resistances of the same type jointed L-type corner joints were tested under static compression and tension loads. Test results indicated that the highest stiffness values were observed with 15 mm PW. This showed that 15 mm plywood could be used instead of 18 mm PW. 16 mm PB and MDF cabinets yielded higher stiffness values than those of 18 mm MDF, PW, and PB. Test results also indicated that 15 mm and 16 mm thick panels can have nearly the same stiffness as 18 mm thick panel.
  • Researchpp 6350-6360Rahmat, B., Pangesti, D., Natawijaya, D., and Sufyadi, D. (2014). "Generation of wood-waste vinegar and its effectiveness as a plant growth regulator and pest insect repellent," BioRes. 9(4), 6350-6360.AbstractPDF
    Wood vinegar (WV) was obtained from charcoal production byproducts. The increase in demand for WV as an alternative pesticide requires more production of WV independent of conventional charcoal production. This research was intended to commence the production of WV from available furniture wood waste. The study included the following: (i) the preparation and performance of a pyrolysis kiln; and (ii) the application of the produced WV as a plant growth regulator of papaya plants in the nursery and as a pest insect repellent during maize storage. These experiments were arranged in a randomized block design. The observed variables included pyrolysis rate, the effect of WV on papaya growth in nursery, and the effect of WV in controlling infestation of maize weevils. The data were analyzed using analysis of variance and continued with Duncan’s multiple difference test. The results showed that while the production of WV continuously occurred until the 90th min, the maximum (139 mL) was reached at the 10th min. Pyrolysis of 1,000 g of chips of wood-planer’s waste yielded WV, tar, bio-oil, and char in quantities of 487.67 mL, 41.76 g, 2.93 mL, and 222 g respectively. The treatment using WV (50 mL/L) increased the diameter of papaya stems in the nursery. Mixing and fuming application of 5 mL of WV as a pest insect repellent on 200 g of maize on the storage could increase the number of the dead maize weevil and reduce the damage maize kernel.
  • Researchpp 6361-6372Sahad, N., Som, A. M., Samsu Baharuddin, A., Mokhtar, N., Busu, Z., and Sulaiman, A. (2014). "Physicochemical characterization of oil palm decanter cake (OPDC) for residual oil recovery," BioRes. 9(4), 6361-6372.AbstractPDF
    A characterization study on oil palm decanter cakes (OPDC) was performed to gain an in-depth understanding of the material’s characteristics to aid in potential residual oil recovery. The OPDC was characterized by a high moisture content, high biodegradability, high organic content, and a nutrient-rich composition. Microscopic observation showed that the oil attachments in OPDC, and a vast majority of the droplets, were less than 50 μm in size. Furthermore, contact angle measurement revealed the hydrophilic and oleophilic characteristics of OPDC. Specifically, the contact angles of water and crude palm oil (CPO) with OPDC were both less than 45° with absorption rates of 0.0265 ± 0.003 µL/s and 0.1042 ± 0.05 µL/s, respectively. The OPDC is a fibrous material, and the surface area and pore size measured were 7.103 m2/g and 481.7 Å, respectively. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis results showed the functional groups and degradation properties of OPDC, respectively.
  • Researchpp 6373-6385Ching, Y. C., and Ng, T. S. (2014). "Effect of preparation conditions on cellulose from oil palm empty fruit bunch fiber," BioRes. 9(4), 6373-6385.AbstractPDF
    The effects of chlorite bleaching on the properties of cellulose derived from oil palm empty fruit bunch (OPEFB) fiber were investigated in this work. Cellulose was extracted from oil palm empty fruit bunch fiber via chlorite bleaching, alkali treatment, and acid hydrolysis. Cellulose was extracted by varying the bleaching duration, which corresponded to 4, 8, or 12 h. Fourier transform infrared (FTIR) analysis showed that the lignin and hemicellulose were significant removed after the bleaching process, whereas no spectral differences were observed in the samples with the increase of bleaching durations. The main removal of the lignin and hemicellulose components had occurred during the bleaching process. There was only slight additional removal of lignin and hemicellulose during the further extraction process with alkali and acid hydrolysis. The peaks at 1740 cm-1 and 1246 cm-1 which represent hemicellulose and lignin, respectively, were not present in the final extracted cellulose.The cellulose yield contents did not increase with the increasing of bleaching duration from 4 h to 12 h. X-ray diffraction (XRD) analysis revealed that the crystallinity and the 200 peak of OPEFB had increased after the bleaching process. Analysis of the visible light transmittance of cellulose, after a bleaching duration of 12 h, demonstrated the highest transmittance due to the disintegration of the fibers. By increasing the bleaching duration, the temperature at 50% weight loss of OPEFB increased, suggesting that the thermal stability of cellulose had improved.
  • Researchpp 6386-6396Liu, S., Wang, Q., Yang, G., and Chen, J. (2014). "Sodium hydrogen sulfite pretreatment of wood pulp waste for enhancement of enzymatic efficiency," BioRes. 9(4), 6386-6396.AbstractPDF
    Wood pulp waste is a type of industrial waste that has an enormous potential for fermentable sugar production. Efficient pretreatment is the key for enhancing the enzymatic efficiency. In this paper, sodium hydrogen sulfite pretreatment was performed on wood pulp waste to improve enzyme performance through sulfonation and hydrolysis reactions. Results showed that the enzymatic efficiency was greatly enhanced from 5.12 to 41.6% in terms of reducing sugar yield (RSY) under the optimum conditions: 6% NaHSO3, 2500 P-factor, 3/1 liquid to solid ratio, and cellulase charge of 35 FPU/g substrate. Mass balance showed that approximately 73% of glucose was recovered. The mechanism of sulfonation and hydrolysis of sodium hydrogen sulfite pretreatment were confirmed by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (X-RD), and scanning electron microscopy (SEM).
  • Researchpp 6397-6407Li, H., Song, K., Zhou, D., and Wu, Q. (2014). "Effect of durability treatment on moisture sorption properties of wood-plastic composites," BioRes. 9(4), 6397-6407.AbstractPDF
    In this study, water absorption and desorption behaviors of wood-plastic composites (WPCs) treated with ultraviolet agents and zinc borate were investigated. Water diffusion characteristics in the composites were analyzed using a one-dimensional diffusion model. The mechanism of water sorption for all composites deviated from Fick’s law of diffusion. Much larger diffusion coefficient values are observed from the desorption process when compared to the absorption process. Measured final equilibrium moisture content and calculated diffusion coefficients varied with sample formulation in a non-consistent manner; this indicated that the durability treatment used in the current study did not negatively affect the water sorption behavior of WPCs. The results of this study help to clarify the effect of durability treatment on the dynamic moisture sorption process of WPCs.
  • Researchpp 6408-6419Li, H., Chen, F., Cheng, H., Deng, J., Wang, G. and Sun, F. (2014). "Large-span bamboo fiber-based composites, Part I: A prediction model based on the Lucas-Washburn equation describing the resin content of bamboo fiber impregnated with different PVAC/PF concentrations," BioRes. 9(4), 6408-6419.AbstractPDF
    To predict the resin absorbing content of bamboo bundle fiber, a model relating to the soaking time and mass ratio of polyvinyl acetate (PVAC) adhesive to phenol formaldehyde (PF) resin defined on the basis of the Lucas-Washburn equation was proposed. Various dipping times and different PVAC/PF ratios were investigated in the experiment. Variance analysis revealed that the resin absorbing content was significantly associated with the ratio of PVAC/PF. However, the soaking time had a significant effect on bamboo fiber resin absorbing content from 0 s to 70 s and had an insignificant effect after 70 s. The results showed that the model proposed could accurately predict the resin absorbing content for bamboo bundle fiber impregnated in different PVAC/PF levels. The comparison of theoretical calculations with experimental results revealed that the residual sum of square and root mean squared error were relatively low, and the correlation coefficients and coefficients of determination were all over 0.95.
  • Researchpp 6420-6431Ng, I. S., Wu, X., Lu, Y., and Yao, C. (2014). "Trichoderma reesei cellulase complex in hydrolysis of agricultural waste of grapefruit peel and orange peel," BioRes. 9(4), 6420-6431.AbstractPDF
    Previous attempts have already been performed for the production of sugars and, later, bioproducts from orange peel using different Trichoderma reesei commercial cocktails in combination with other kinds of enzymes. In this study, the feasibility of simple pretreatments combined with enzymatic treatments was compared between grapefruit inner peel (GFIP), orange inner peel (OIP), grapefruit whole peel (GFWP), and orange whole peel (OWP). The four biomaterials were characterized with respect to the contents of cellulose and hemi-cellulose, elemental analysis, and Fourier transform infrared (FTIR) spectrometry. The 3,5-dinitrosalicylic acid assay demonstrated that GFIP and OIP produced 31.7% and 34.9% more reducing sugar than GFWP and OWP, respectively. Further investigation of the bioprocess showed the optimal conditions include the following: (i) a solid to liquid ratio of 4%, (ii) enzymatic activity of 0.075 U/mL, and (iii) reaction at 55 °C and a pH of 5.0. Moreover, the major products after cellulolytic hydrolysis were fructose, glucose, and cellobiose. This study provides an alternative and effective approach to extend the utilization of agricultural waste in the fields of food and energy.
  • Researchpp 6432-6439Axelsson, A. (2014). "How planer settings affect timber properties," BioRes. 9(4), 6432-6439.AbstractPDF
    There are different reasons for planing timber. One is to adjust the cross-sectional dimensions of thickness and width. Another is to adjust the timber's outer shape, usually in order to reduce warp resulting from drying and having the forms of cup, twist, bow, and crook. The end-result depends on the properties of the timber before planing and on the planer design and settings. In the present work it was found that increasing or decreasing the forces exerted on the timber by a four-sided planer does not affect the cutting depth or the twist reduction. The pressure settings do not affect the rectangularity or the amount of unplaned areas on the surfaces either. The possibility to impact the result with this type of planer, apart from the cutting depth and planed dimensions, is slim to none.
  • Researchpp 6440-6452Liang, M., He, B., and Zhao, L. (2014). "Hydrophobicity of lime sludge filled paper assisted by a cationic starch/CPAM/bentonite retention aids," BioRes. 9(4), 6440-6452.AbstractPDF
    Lime sludge is a special type of precipitated calcium carbonate (PCC) recovered from black liquor, which can be used as paper filler in the paper-making process. However, one of the biggest problems when lime sludge is used as filler is that it is difficult to hydrophobically size the filled paper, especially in the case of paper with high filler content. Also, the efficient retention of the sizing agent AKD is a fundamental requirement for effective paper hydrophobic sizing. Therefore, in this work, a ternary retention aids system, cationic starch/CPAM/bentonite, was applied, and the hydrophobic sizing degree of lime sludge filled paper sheets and filler retention were evaluated. The results showed that the retention of lime sludge was significantly influenced by CPAM and was overall increased as the dosage of CPAM increased; cationic starch showed a more significant influence on paper Cobb value than filler retention; relative lower Cobb values and higher filler retention were achieved at lower bentonite dosage. At 0.75% cationic starch, 0.043% CPAM, and 0.3% bentonite, a substantial high hydrophobic sizing efficiency of Cobb value (45.72 g/m2) and filler retention (80.37%) were achieved simultaneously due to the synergetic performance of a cationic starch/CPAM/bentonite retention aids system.
  • Researchpp 6453-6462Parobek, J., Paluš, H., Kaputa, V., and Šupín, M. (2014). "Analysis of wood flows in Slovakia," BioRes. 9(4), 6453-6462.AbstractPDF
    This paper describes the analysis of raw wood flows in Slovakia. Material flow analysis was used to reveal and quantify relations between the resources and the primary uses of wood. In particular, two approaches to wood flow modelling were utilised - wood balance and wood resource balance. Wood balance was introduced to illustrate a global view of the resources and primary uses of roundwood in Slovakia without analysing internal flows or individual roundwood assortments, respectively. The wood resource balance, as a more detailed analysis, takes into account the uses of wood as a material and also the by-products and waste generated by the production that could be used as inputs for further uses in wood processing or energy sectors. The latter balance was compiled using available official statistics supplemented by a questionnaire to estimate missing data for waste streams. With a total consumption of 11.964 mil. m3 roundwood equivalents, the value of the overall cascade factor was 1.11. Over 84% of all resources were used for industrial purposes, and nearly 16% were used for energy generation.
  • Researchpp 6463-6475Yang, C.-N., Hung, K.-C., Wu, T.-L., Yang, T.-C., Chen, Y.-L., and Wu, J.-H. (2014). "Comparisons and characteristics of slicewood acetylation with acetic anhydride by liquid phase, microwave, and vapor phase reactions," BioRes. 9(4), 6463-6475.AbstractPDF
    This study compared and characterized slicewood acetylation with acetic anhydride using conventional liquid phase, microwave, and vapor phase reactions. The results revealed that there were no significant differences in the flexural properties between the unmodified and acetylated slicewood, regardless of the reaction method used. Furthermore, findings concluded that the slicewood acetylated with a vapor phase reaction required less modifying agent to achieve high levels of weight percent gain (WPG). The correlations between the anti-swelling efficiency (ASE) and the WPG of the slicewood acetylated with a vapor phase reaction were higher than the conventional liquid phase and microwave reactions. The reactivity of the cellulose hydroxyl groups was sensitive to the C2 and C6 reactive sites for all three acetylation methods. However, the reactivity was more pronounced at the C2 position with a vapor phase reaction compared to the other two reactions. Nevertheless, slicewood acetylation with acetic anhydride was found to not have a significant influence on viscoelastic properties for any of the different reaction methods.
  • Researchpp 6476-6489Wang, K.-Q., Chen, J.-P., Chen, L., Wu, X.-F., Su, X. J., Amartey, S., and Qin, W. (2014). "Isolation and irradiation-modification of lignin specimens from black liquor and evaluation of their effects on wastewater purification," BioRes. 9(4), 6476-6489.AbstractPDF
    In this study, crude lignin extracted from the black liquor generated by a pulp and paper mill was modified by different doses of irradiation. The crude and irradiation-modified lignins were used to treat wastewater that was generated during the production of starch glucoamylase. Changes to the physical and chemical properties and structure of the irradiation-modified lignins were determined using scanning electron microscopy, solubility analysis, elemental analysis, analysis of phenolic hydroxyl group, ultraviolet–visible spectroscopy, and Fourier transform infrared spectroscopy. Irradiation reduced the phenolic hydroxyl content in the lignin but increased its solubility by about 40%; analysis revealed that irradiation also destroyed the skeletal structure of the benzene ring in the lignin. After four minutes of settling, the total nitrogen (TN) and chemical oxygen demand (COD) in the wastewater reached 7.0 mg/L and 1573.1 mg/L, respectively. The settled solids content and protein recovery were 1.12 g/L and 98%, respectively. This study suggested that irradiation-modified lignin extracted from black liquor generated in the pulp and paper industry can be used to treat wastewater from the production of starch glucoamylase.
  • Researchpp 6490-6503Cavdar, A. D., Mengeloglu, F., Karakus, K., and Tomak, E. D. (2014). "Effect of chemical modication with maleic, propionic, and succinic anhydrides on some properties of wood flour filled HDPE composites," BioRes. 9(4), 6490-6503.AbstractPDF
    One of the biggest disadvantages of wood, as a potential reinforcement for thermoplastics, is its hydrophilicity. The aim of this study was to evaluate the effect of chemical modification of wood flour on mechanical, thermal, and fire properties of filled high-density polyethylene composites. For this purpose, aspen flour was modified with maleic, propionic, and succinic anhydrides. The modified wood flour and high-density polyethylene were compounded into pellets by single-screw extrusion, and test samples were prepared by injection molding. Tensile and flexural tests, impact testing, limiting oxygen index, TGA, and SEM analyses were conducted both for modified and un-modified samples. Based on the test results, chemical modification enhanced the properties of thermoplastic composites. Depending on the chemical concentrations, the flexural, tensile, and impact strengths of the modified flour filled HDPE composites were improved slightly, while the tensile and flexural moduli of the samples were increased significantly. The limiting oxygen index (LOI) levels of samples with modified wood flour were slightly improved, and succinic anhydride provided higher LOI levels compared to the samples with other anhydrides. This showed that the composites filled with chemically modified wood flour were slightly more thermally stable than control samples. It appears that wood flour modified with maleic, propionic, and succinic anhydrides can be successfully utilized as filler in polymer matrices.
  • Researchpp 6504-6513Jiao, C., and Xiong, J. (2014). "Accessibility and morphology of cellulose fibres treated with sodium hydroxide," BioRes." 9(4), 6504-6513.AbstractPDF
    Cellulose fibres were treated with sodium hydroxide (NaOH) to improve the accessibility of chemical reagents and the roughness of fibre surface at low temperatures. The accessibility, supermolecular structure, morphology, and physical properties of fibres were investigated using solid-state cross polarisation/magic angle spinning 13C nuclear magnetic resonance (CP/MAS 13C NMR), wide-angle X-ray diffraction (WAXD), and scanning electron microscopy (SEM). The results showed that in low temperature (-16 °C), the iodine sorption value of cellulose fibres is 145.2 mg. The shift from the C6 signal of the molecular structure to the amorphous area indicated a decrease in the crystallinity of the material from 66% to 8%, and the transformation from cellulose I to II occurred. The SEM revealed fold shapes in the fibre surface, which increased the fibre surface area.
  • Researchpp 6514-6526Pérez-Guerrero, P., Lisperguer, J., Navarrete, J., and Rodrigue, D. (2014). "Effect of modified Eucalyptus nitens lignin on the morphology and thermo-mechanical properties of recycled polystyrene," BioRes. 9(4), 6514-6526.AbstractPDF
    The morphology and thermo-mechanical properties of recycled polystyrene-based materials (rPS) reinforced with 5 and 15% lignin from kraft pulping of Eucalyptus nitens were studied. The lignin was modified through two esterification processes using either acetic or maleic anhydride, and changes in the structure of the esterified lignin functional groups were analyzed by Fourier transform infrared spectroscopy. The lignin was then incorporated into rPS by melt mixing. Torque variation in the process was evaluated, and the values were compared to those of neat rPS and virgin PS. The results show a plasticizing effect of lignin with a reduction in the torque values. The morphology, studied through scanning electron microscopy, shows a particle size reduction of acetylated and maleated lignin and a more homogeneous dispersion at 5%. The thermal behavior of the composites, studied through differential scanning calorimetry, does not show significant changes in the glass-transition temperature of rPS with the presence of lignin. The dynamic mechanical analysis shows an increasing storage modulus with increasing lignin content. Thermal stability, studied through thermogravimetric analysis, improved for composites containing 5% esterified lignin. The flexural modulus also increased with lignin addition. These results suggest that the thermal and mechanical properties of post-consumer recycled polystyrene can be significantly improved with only 5% esterified lignin.
  • Researchpp 6527-6539Espinoza, O., Buehlmann, U., Bumgardner, M., and Smith, R. (2014). "Intermediaries in the U.S. hardwood lumber market: Comparing and contrasting sawmills and distributors," BioRes. 9(4), 6527-6539.AbstractPDF
    The objective of this study was to better understand changes in the hardwood lumber supply chain from the perspective of lumber producers and distributors and to assess the degree of judgmental convergence between suppliers and buyers of hardwood lumber. Results from two nationwide surveys conducted in 2008 and 2009 were used for the analysis. Findings confirmed a decline in demand for red oak and an increase in species diversity in the market, although a majority of sales were dominated by five species. Results also showed an increasing importance of markets for lower grades of lumber, such as pallets, containers, and railroad ties, and a decline in demand for higher-value products such as furniture and kitchen cabinets. The importance of the lumber distributor role in the hardwood supply chain also has increased. Both sawmills and suppliers have increased their offerings of customized products and services in response to market demand. The customer base is changing, with smaller, more customized orders being sold to smaller businesses. Some of the trends and changes identified are structural and long-running in nature and are not expected to change in the short term.
  • Researchpp 6540-6561Zoia, L., Salanti, A., Frigerio, P., and Orlandi, M. (2014). "Exploring allylation and claisen rearrangement as a novel chemical modification of lignin," BioRes. 9(4), 6540-6561.AbstractPDF
    The conversion of lignin into value-added products is traditionally hampered by its stochastic structure and its complex reactivity. The allylation reaction and the aromatic Claisen rearrangement of the allyl group on lignin as chemical modifications are reported for the first time in this work. This approach is aimed at the development of new lignin-based materials and the improvement of its compatibility and ease of processing. In particular, the Claisen rearrangement of lignin is foreseen as a valuable approach to release phenolic groups in an already chemically modified lignin, giving additional reactive sites for further transformation. These reactions were carried out on a purely guaiacylic lignin (TMP), taken as reference material due to its simplicity, and on a more structurally complex herbaceous lignin (P1000®). The Claisen rearrangement of the allylic chain was successfully achieved by treatment in dimethylformamide at reflux temperature for 15 hours. Finally, a screening of the antioxidant activity of reference, allylated, and Claisen rearranged lignins was carried out. Rearranged lignins exhibited satisfactory antioxidant activities if compared to the reference ones.
  • Researchpp 6562-6581McGavin, R. L., Bailleres, H., Lane, F., Fehrmann, J., and Ozarska, B. (2014). "Veneer grade analysis of early to mid-rotation plantation Eucalyptus species in Australia," BioRes. 9(4), 6562-6581.AbstractPDF
    Processing Australian hardwood plantations into rotary veneer can produce more acceptable marketable product recoveries compared to traditional processing techniques (e.g. sawmilling). Veneers resulting from processing trials from six commercially important Australian hardwood species were dominated by D-grade veneer. Defects such as encased knots, gum pockets, gum veins, surface roughness, splits, bark pockets, and decay impacted the final assigned grade. Four grading scenarios were adopted. The first included a change to the grade limitations for gum pockets and gum veins, while the second investigated the potential impact of effective pruning on grade recovery. Although both scenarios individually had a positive impact on achieving higher face grade veneer qualities, the third and fourth scenarios, which combined both, had a substantial impact, with relative veneer values increasing up to 18.2% using conservative calculations (scenario three) or up to 22.6% (scenario four) where some of the upgraded veneers were further upgraded to A-grade, which attracts superior value. The total change in veneer value was found to depend on the average billet diameter unless defects other than those relating to the scenarios (gum or knots) restricted the benefit of pruning and gum upgrading. This was the case for species prone to high levels of growth stress and related defects.
  • Researchpp 6582-6590Shen, W., and Li, J. (2014). "Reinforcing effects of UHMWPE fiber on the mechanical properties of woods," BioRes. 9(4), 6582-6590.AbstractPDF
    Three layers of wood-based composites of planed lumber-UHMWPE-veneer structure were prepared using polyurethane (PUR) as the resin matrix. The effects of ultrahigh molecular weight polyethylene (UHMWPE) fiber on the wood’s bending performance, tensile properties, and other mechanical properties, such as shear resistance to the agglutination interface, were investigated. Chemical constituents of debonded fibers were characterized by infrared spectroscopy (FTIR). The results show that PUR could feasibly be used to manufacture UHMWPE fiber/wood composites. UHMWPE fiber played an important role in the wood destruction process and improved the flexural performance of the lumber. This positive effect was closely related to the thickness of veneer. When fiber was within the load-bearing strength range, there was a positive correlation between the tensile strength and the bonding distance. Meanwhile, the reinforcing effect of UHMWPE fiber strongly affects the performance of the bonding interface under shear.
  • Researchpp 6591-6613Trischler, J., Sandberg, D., and Thörnqvist, T. (2014). "Evaluating the competition of lignocellulose raw materials for their use in particleboard production, thermal energy recovery, and pulp- and papermaking," BioRes. 9(4), 6591-6613.AbstractPDF
    There is increasing competition for raw materials between particleboard production, thermal energy recovery, and pulp- and papermaking. According to different scenarios, the consumption of lignocellulosic raw materials is increasing, which means that the competition is increasing. The primary production of lignocellulosic raw material in some regions may therefore reach the limit of sustainability; i.e., the lignocellulosic raw material must be used more efficiently to reduce the risk of a shortage. The physical and chemical properties of the lignocellulosic raw material of selected species have therefore been surveyed, and the raw material properties that are important for each of the three competitors have been defined. The aim of the study is to characterise the lignocellulosic raw materials according to the three competing users and to show whether they are high or low in competition. As methods, a relative ranking of the species regarding their raw material properties and regarding the requirements of the competitors as well as cluster analysis were chosen. The results show that the most favourable raw materials are from coniferous species, while monocotyledon species show an opposite trend.
  • Researchpp 6614-6626Abdul Khalil, H. P. S., Dungani, R., Ahmed Mohammed, I., Hossain, M. S., Aprilia, N. A. S., Budiarso, E., and Rosamah, E. (2014). "Determination of the combined effect of chemical modification and compression of agatis wood on the dimensional stability, termite resistance, and morphological structure," BioRes. 9(4), 6614-6626.AbstractPDF
    Agatis wood (Agathis lorantifolia Salisb.) was impregnated with a combination of styrene and methyl methacrylate and compressed to a strain of 50% to improve dimensional stability and termite resistance. The changes in cell structure were analyzed to determine the effects of the combination treatment. The results showed that densification of agatis wood with compression, impregnation, and a combination of treatments resulted in an increase in physical properties (density and dimensional stability) by changing the cellular structure and chemical components (i.e., cellulose crystallinity, microfibril angle, and preferred orientation of fibers) as well as degradation of cellulose. The chemical modification and combination treatment (chemical and compression) of wood generally led to a high resistance to dry wood termites.
  • Researchpp 6627-6643Deng, H., Yu, H., Chen, M., and Ge, C. (2014). "Sorption of atrazine in tropical soil by biochar prepared from cassava waste," BioRes. 9(4), 6627-6643.AbstractPDF
    Biochar (BC) is a carbonaceous and porous product generated from the incomplete combustion of biomass and has been recognized as an efficient adsorbent. This study evaluated the ability of BC to sorb atrazine pesticide in tropical soil, and explored potential environmental values of BC on mitigating organic micro-pollutants. BC was produced from cassava waste via pyrolyzation under oxygen-limiting conditions at 350, 550, and 750 °C (MS350, MS550, and MS750, respectively). Three biochars were characterized and investigated as sorbents for the removal atrazine from tropical soil. BC pyrolyzed at higher temperatures more quickly reached equilibrium. The pseudo-second-order model perfectly simulated the sorption kinetics for atrazine with the coefficients R2 above 0.996, and the sorption amount at equilibrium (qe) was 0.016 mg/g for MS350, 0.025 mg/g for MS550 and 0.050 mg/g for MS750. The isotherms of MS350 displayed relatively linear behavior, whereas the sorption of atrazine on MS550 and MS750 followed a nonlinear isotherm. The sorption data were well described by the Freundlich model with logKF of 0.476 for MS350, 0.771 for MS550, 1.865 for MS750. A thermodynamic study indicated that the sorption of atrazine in BC-added soil was a spontaneous and endothermic process and was primarily controlled by physisorption. In addition, lower pH was conducive to the sorption of atrazine in BC-added soil.
  • Researchpp 6644-6651Tolvaj, L., Nemeth, R., Pasztory, Z., Bejo, L., and Takats, P. (2014). "Colour stability of thermally modified wood during short-term photodegradation," BioRes. 9(4), 6644-6651.AbstractPDF
    Dry thermal treatments of wood samples were carried out at 160 and 200 °C. After each treatment, the samples were irradiated using a strong UV emitter mercury lamp, and the colour change was then evaluated. For control, untreated samples were also irradiated using the same mercury lamp. Results showed that the extractive content of the wood played an important role in the colour change not only during thermal treatment but also during light irradiation. It was found that, compared to the thermally untreated samples, the thermal treatment at 200 °C reduced the red colour change due to photodegradation. The yellow colour change of photodegradation was hardly affected by the applied thermal treatments, showing that thermal treatments were not able to reduce the light degradation of lignin. The applied treatments slightly stabilized the wood against the degrading effect of light. The wood treated at lower temperature (160 °C) had less colour change induced by the light source.
  • Researchpp 6652-6668Wherry, G., and Buehlmann, U. (2014). "Product life cycle of the manufactured home industry," BioRes. 9(4), 6652-6668.AbstractPDF
    Residential construction consumes an estimated 26 percent of the total U.S. wood harvest and thus plays an important role in the forest products value chain. While being a relatively small part of the U.S. residential construction market, the factory-built residential housing industry, originating from manufactured homes (e.g. mobile homes), is embracing emerging industry segments such as modular or panelized homes. Since indications exist that factory-built home production is slated to gain a more prominent role in the U.S. construction markets at the cost of traditional stick-built production, the factory-built home industry sub-segment is of considerable importance to the forest products industry. This research looks at manufactured home producers as a benchmark for analyzing the current economic state of the industry and discusses competitive strategies. The analysis concludes, through macroeconomic modeling, that manufactured homes are in the declining stage of their product life cycle due to changes to the U.S. residential construction sector and the factory-built home industry and by advancements of rival industry-segments. As market share continues to decline, firms operating in this industry-segment seek to either hedge their losses through product diversification strategies or remain focused on strategically repositioning the manufactured home segment.
  • Researchpp 6669-6681Li, H., Song, X., Liu, X., Li, C., Xu, J., Qu, M., Wu, Z., Cheng, X., and Xiao, C. (2014). "The human physiological response to volatiles from Juniperus chinensis cv. Kaizuka and Pistachia chinensis Bunge," BioRes. 9(4), 6669-6681.AbstractPDF
    Effects of volatiles from Pistacia chinensis Bunge and Juniperus chinensis cv. Kaizuka on human emotions were investigated. The volatiles were analyzed using a gas chromatograph-mass spectrometer (GC-MS). Human emotions were defined and measured using several physiological indices, including oxygen saturation of blood (OSB), finger temperature (FT), pulmonary ventilation volume (PVV), and electrocardiograph (ECG). These indices were measured using a multi-conductive physiology technique. The results showed that after participants had inhaled volatiles from P. chinensis Bunge, their OSB and FT decreased significantly (P<0.05) in comparison to the control group, while the PVV increased. After inhaling the volatiles from J. chinensis cv. Kaizuka, the OSB and FT increased, while the PVV decreased. In addition, women’s FT and PVV and men’s OSB and PVV differed significantly from those of the control group (P<0.05). Some ECG indices were also affected by the inhalation of volatiles. These results indicated that people tend to feel more excited or nervous when in the presence of P. chinensis Bunge, and more relaxed and comfortable while in the presence of J. chinensis cv. Kaizuka.
  • Researchpp 6682-6698Li, H. X., Zhang, R. J., Tang, L., Zhang, J. H., and Mao, Z. G. (2014). "Use of cassava residue for the removal of Congo red from aqueous solution by a novel process incorporating adsorption and in vivo decolorization," BioRes. 9(4), 6682-6698.AbstractPDF
    To investigate the removal of Congo red (CR) from an aqueous solution using cassava residue, a novel process incorporating adsorption and in vivo decolorization was proposed. The conditions and characteristics of CR adsorption on cassava residue were investigated by batch adsorption experiments. Langmuir and pseudo-second order models were found to fit well with the data of equilibrium adsorption and kinetics adsorption, respectively. The adsorption was affected considerably by the adsorbent (cassava residue) dosage and CR concentration. The maximum adsorptive capacity was 59.2 mg/g (mCR/mcassava residue), calculated by the Langmuir model. Then, CR-loaded cassava residue was further decolorized via an in vivo process by Trametes sp. SYBC-L4 . The laccase produced by Trametes sp. SYBC-L4 effectively decolorized CR, which was revealed by native polyacrylamide gel electrophoresis. The moisture content affected the performance of in vivo decolorization considerably. Decolorization of 81.6 ± 2.4% was achieved under the conditions of pH 5.5, temperature 30 °C, and moisture content of 60% after 16 days of cultivation. Moreover, analyses of Fourier transform infrared spectroscopy and scanning electron microscopy indicated that the carbonyl (C=O), hydroxyl (-OH), and amino (-NH) groups in cassava residue were the potential adsorption sites for interaction with CR and that the structure of cassava residue was modified in the process of in vivo decolorization.
  • Researchpp 6699-6706Ge, Y., Wei, Q., and Li, Z. (2014). "Preparation and evaluation of the free radical scavenging activities of nanoscale lignin biomaterials," BioRes. 9(4), 6699-6706.AbstractPDF
    There is much research on nanomaterial from natural polymer because of its biocompatibility, abundance, and non-toxicity. This work is devoted to the study of free radical scavenging activities (FRSA) of nanoscale lignin biomaterials, which are recognized as promising natural antioxidants. The nanoscale lignin biomaterials were prepared from alkaline lignin by a solution-precipitation method with either ethylene glycol (NL1) or alkaline solution (NL2). Structural analysis of the nanoscale lignin biomaterials were conducted by Scanning electron microscopy (SEM), laser particle size analyzer, Fourier transform-infrared spectroscopy (FT-IR), potentiometric titration, and gel permeation chromatography (GPC). The results indicated that NL2 had a smaller average particle size (278±13 nm) than NL1 (375±18 nm) and contained more phenolic hydroxyl groups (2.35±0.11 mmol/g) and had a lower weight-average molecular weight (Mw=6510±320). The FRSA of the biomaterials towards hydroxyl free radicals were measured and compared with the alkaline lignin. Some structure-activity relationships were proposed based on the analysis of experiment data, which revealed NL2 (IC50=0.18±0.01 mg/mL) had a 3.33 fold higher activity than NL1 (IC50=0.60±0.05 mg/mL), which could be attributed to the smaller particle size, more phenolic hydroxyl group, and lower weight-average molecular weight.
  • Researchpp 6707-6718Yuan, H., Zhang, Y., Li, X., Meng, Y., Liu, C., Zou, D., and Liu, Y. (2014). "Effects of ammoniation pretreatment at low moisture content on anaerobic digestion performance of rice straw," BioRes. 9(4), 6707-6718.AbstractPDF
    The effect of ammonia pretreatment on the anaerobic digestion performance of rice straw was investigated. The rice straw was pretreated with four different moisture contents (30%, 50%, 70%, and 90%) and three concentrations of ammonia (2%, 4%, and 6%). The results showed that the anaerobic digestion achieved best performance for the rice straw pretreated by ammonia concentration of 4% and moisture content of 70%, and biogas yield achieved the highest value (396.92 mL·g-1 total solid ), which was 21.9% higher than that of the untreated rice straw. Higher moisture was recommended as it could increase system stability, shorten anaerobic digestion time, and increase biogas production. The composition analyses indicated that ammonia pretreatment could effectively destroy the chemical structure of lignocellulose, and partially decompose cellulose, hemicellulose, and lignin. Cellulose and hemicellulose were converted by 79.2% and 63.2%, respectively, at optimal ammonia amount and moisture content. The ammonia pretreatment proved to be a simple and effective methods to improve the anaerobic digestion performance of rice straw.
  • Researchpp 6719-6734Chen, X., Xie, M., Wang, H., Xue, Y., and Li, Z. (2014). "Preparation of silica by alkaline-heating and precipitation method from corn straw ash," BioRes. 9(4), 6719-6734.AbstractPDF
    The preparation of silica by an alkaline-heating and precipitation method from corn straw ash (CSA) obtained from a biomass power plant was the focus of this study. Sodium hydroxide was used as the silica extraction reagent, and H2SO4 was the precipitator. The concentration of sodium hydroxide solution was confirmed to have a significant influence on the production of sodium silicate from CSA. The optimum technological parameters for the preparation of sodium silicate and the suitable parameters for the preparation of silica were obtained by experiments and analysis. Fourier transform infrared spectroscopy (FT-IR) was used for confirming that the as-obtained silica has characteristic IR absorption peaks of typical hydrated silicon dioxide. The microstructures of the as-obtained silica products were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Comparison using HG/T3061 (2009) standards, and the characteristics of silica products were used to estimate whether the as-obtained silica products reached market requirements. The results show that the silica products are superior to the standard requirements and have a large market potential.
  • Researchpp 6735-6744Santos, A. J. A., Anjos, O., Simões, R., Rodrigues, J., and Pereira, H. (2014). "Kappa number prediction of Acacia melanoxylon unbleached kraft pulps using NIR-PLSR models with a narrow interval of variation," BioRes. 9(4), 6735-6744.AbstractPDF
    A total of 120 Acacia melanoxylon R. Br. (Australian blackwood) stem discs, belonging to 20 trees from four sites in Portugal, were used in this study. The samples were kraft pulped under standard identical conditions targeted to a Kappa number of 15. A Near Infrared (NIR) partial least squares regression (PLSR) model was developed for the Kappa number prediction using 75 pulp samples with a narrow Kappa number variation range of 10 to 17. Very good correlations between NIR spectra of A. melanoxylon pulps and Kappa numbers were obtained. Besides the raw spectra, also pre-processed spectra with ten methods were used for PLS analysis (cross validation with 48 samples), and a test set validation was made with 27 samples. The first derivative spectra in the wavenumber range from 6110 to 5440 cm-1 yielded the best model with a root mean square error of prediction of 0.4 units of Kappa number, a coefficient of determination of 92.1%, and two PLS components, with the ratios of performance to deviation (RPD) of 3.6 and zero outliers. The obtained NIR-PLSR model for Kappa number determination is sufficiently accurate to be used in screening programs and in quality control.
  • Researchpp 6745-6755Xu, B., Liu, S., and Zhu, T. (2014). "Comparison of variations in the chemical constituents of the rhizome and culm of Phyllostachys pubescens at different ages," BioRes. 9(4), 6745-6755.AbstractPDF
    A systematic study was conducted on Phyllostachys pubescens by analyzing the chemical constituents of its rhizome and culm at different ages. Our results indicated that the ash contents of the rhizome and culm of P. pubescens at different ages showed the largest coefficient of variation (CV), followed by alcohol benzene extractives. The CVs of acid-insoluble lignin, holocellulose, HNO3-C2H5OH cellulose, and pentosan were relatively small. Analysis of t-tests indicated that significant differences were found in the contents of extractives, acid-insoluble lignin, holocellulose, and ash of rhizome and culm (p < 0.05). The differences in contents of HNO3-C2H5OH cellulose and pentosan were not significant. Analysis of multiplicity showed that the contents of HNO3-C2H5OH cellulose, pentosan, and ash were not significantly different in bamboos at the ages examined. Likewise, the contents of lignin, alcohol benzene extractives, and holocellulose exhibited no significant difference between one-year-old and three-year-old bamboos. However, the differences in these parameters between five-year-old bamboos and one- and three-year-old bamboos were all statistically significant. Our results suggest that three-year-old P. pubescens is suitable for use as a raw material for papermaking. In addition, our findings provide a theoretical basis for effective utilization of P. pubescens and enhancement of its value.
  • Researchpp 6756-6764Said, N., Abdel daiem, M. M., García-Maraver, A., and Zamorano, M. (2014). "Reduction of ash sintering precursor components in rice straw by water washing," BioRes. 9(4), 6756-6764.AbstractPDF
    The thermal conversion of rice straw is an attractive option for recovering its energy, but the process requires exhaustive control because of ash-related problems. Straw washing is one method of reducing ash-related problems and improving combustion behaviour. In this study, the ash of washed and unwashed rice straw samples was chemically characterized, tested using thermogravimetric analysis and environmental scanning electron microscopy (ESEM), and subjected to higher combustion temperatures in a muffle furnace. Results showed that silicon was the most important component in the ash. Furthermore, a reduction in undesirable inorganic compounds related to ash problems, such as chlorine and potassium, was achieved by washing the straw samples. This practice could improve thermal behaviour and decrease the sintering formation of ash.
  • Researchpp 6765-6777Deng, J., Li, H., Zhang, D., Chen, F., Wang, G., and Cheng, H. (2014). "The effect of joint form and parameter values on mechanical properties of bamboo-bundle laminated veneer lumber (BLVL)," BioRes. 9(4), 6765-6777.AbstractPDF
    Bamboo-bundle laminated veneer lumber (BLVL) was produced by joint lengthening technology. The objective of this study was to evaluate the effect of joint form and the values of key parameters on mechanical properties of BLVL. Two joint forms, i.e., finger joint and scarf joint, and two corresponding joint parameters, i.e., finger length and scarf angle, were investigated in laminates. The results indicated that the mechanical properties of jointed BLVL were reduced in comparison to those of BLVL without joints. For finger-joint form, the BLVL member with 14 mm fingers achieved better compressive strength, bending modulus of rupture (MOR), and tensile strength than 19 and 25 mm ones. For scarf-joint form, the 30° scarf-jointed member exhibited the highest bending modulus and tensile modulus of rupture (MOR) in this study, then followed the 45° and 60° ones. The 60° scarf-jointed BLVLs were better than 30° and 45° groups in compression strength. Synthesis of the testing results revealed that finger-jointed BLVLs achieved better bending modulus of rupture than scarf-jointed ones.
  • Researchpp 6778-6790Yu, X., Yang, R., Gu, Z., Lai, S., and Yang, H. (2014). "Anti-tumor and immunostimulatory functions of two feruloyl oligosaccharides produced from wheat bran and fermented by Aureobasidium pullulans," BioRes. 9(4), 6778-6790.AbstractPDF
    Feruloyl oligosaccharide 1 (FO1) and feruloyl oligosaccharide 2 (FO2) were produced from wheat bran fermented by Aureobasidium pullulans (A. pullulans) through one- and two-stage temperature and pH controlling processes, respectively. Here the anti-tumor and immunostimulatory functions of FO1 and FO2 were further examined. Both FO1 and FO2 inhibited the growth of cancer cells but were non-toxic to normal cells in vitro. In S180 tumor-bearing mice, both FO1 and FO2 significantly inhibited the growth of transplanted tumors and promoted thymus, spleen indexes, interferon-γ, and interleukin-3 production. They also increased peripheral leukocyte count and bone-marrow cellularity. The biological activity of FOs prepared by different processes was further determined. Interestingly, FO2 possessed more potent anti-tumor and immunostimulatory effect than FO1 in a dose-dependent manner. At a dose of 250 mg/kg, the tumor inhibition rates for FO1 and FO2 were 22.42% and 44.85%, respectively. These antitumor properties of FOs may be mediated by their beneficial effects on immunity responses. These data suggest that FOs from wheat bran may be used as anti-tumor agents in the future.
  • Researchpp 6791-6804Bashir, R., Syed, Q., Mumtaz, M. W., Anwar, F., Saari, N., and Adnan, A. (2014). "Growth kinetics, purification, and characterization of AbstractPDF
    In this study, banana waste was used to investigate its elicitation potential for induced production of α-amylase from Bacillus licheniformis DSM-1969. Initially, six different media were investigated to select the composition with optimal yield. A comparison of the fermentations in the stirred fermenter or shake flasks revealed that B. licheniformis DSM-1969 was more active to synthesize α-amylase in the fermenter as compared to the shake flask. In the shake flask during the exponential phase, the specific growth rate, generation time, and number of generations were 0.19 h-1 , 3.48 h-1, and 5.16 h-1, respectively, whereas in the stirred fermenter the above values were 0.3 h-1, 2.31 h-1 and 5.21 h-1, respectively. A significant difference was recorded in the specific substrate uptake rate and biomass growth yield during the exponential phase in the stirred fermenter in comparison to the shake flask. The enzyme was purified by ion-exchange chromatography using fast protein liquid chromatography (FPLC). α-amylase was purified 3.9 fold with a specific activity of 38.8 U/mg and molecular weight of 62 kDa. Characterization revealed that purified α-amylase remained stable over a broad pH and temperature range as compared to the crude enzyme. Activity of this novel extra thermo-stable α-amylase was stimulated to variable extents by Zn2+, Co2+, and Mn2+, whereas EDTA and Hg2+ showed inhibitory effects.
  • Researchpp 6805-6816Ciobanu, V. D., Zeleniuc, O., Dumitrascu, A. E., Lepadatescu, B., and Iancu, B. (2014). "The influence of speed and press factor on oriented strand board performance in continuous press," BioRes. 9(4), 6805-6816.AbstractPDF
    Three-layer cross-oriented strand boards, OSB type 3 of 10 mm thick, were industrially manufactured from a mixture of wood species including 50% softwoods, 25% beech, and 25% low hardwoods, using a continuous press line. The effects of line speed and press factor on physical and mechanical properties of OSB/3 (exterior grade) were evaluated, keeping nearly constant the face-core adhesive ratio. The manufactured boards were classified into five groups depending on the pressing parameters. The experimental results showed that all mechanical properties increased, with increasing press factor and decreasing line speed. The ratios of bending strength (MOR) and the modulus of elasticity (MOE) parallel to perpendicular were 1.73 to 1.89 and 2.18 to 2.24, respectively. No significant differences in thickness swell and water absorption were observed. The lowest density was achieved at higher speed, although there was no large variation in densities between groups. Thickness swelling and internal bond after boil test exceeded the EN 300 standard requirements for OSB/3 moisture resistance, excepting a few boards. The results revealed that a correlation between speed and press factor is necessary in order to improve mechanical properties and to keep the physical performance of boards within a limited range of values.
  • Researchpp 6817-6830Wu, S., Jameel, H., Chang, H. M., and Phillips, R. (2014). "Techno-economic analysis of the optimum softwood lignin content for the production of bioethanol in a repurposed kraft mill," BioRes. 9(4), 6817-6830.AbstractPDF
    Kraft pulping is one possible pretreatment for softwood to economically produce bioethanol. This work evaluates the techno-economic potential of using the kraft process for producing bioethanol from softwoods in a repurposed or co-located kraft mill. Pretreated loblolly pine was enzymatically hydrolyzed at low enzyme dosages of 5 and 10 FPU/g of substrate. Pretreated residue with 13% lignin content had the highest sugar recovery, 32.7% and 47.7% at 5 and 10 FPU/g, respectively. The pretreated residues were oxygen delignified and refined. In all cases, oxygen delignification improved sugar recovery, while refining was mostly effective for pulps with high lignin content. At 5 FPU/g, the sugar recovery for all kraft pulps was 51 to 53% with oxygen delignification and refining. Increasing the enzyme dosage to 10 FPU/g increased the sugar recovery for these pulps to greater than 60%. Economic analysis for the pulps with different initial lignin content showed that kraft pulps with an initial lignin content of 6.7% with oxygen delignification had an ethanol yield of 285 L/ODt wood and the lowest total production cost of $0.55/L. Pulps with initial lignin content of 18.6% had a total production cost of $0.64/L with an ethanol yield of 264 L/ODt wood.
  • Researchpp 6831-6840Jin, Z., and Zhao, G. (2014). "Porosity evolution of activated carbon fiber prepared from liquefied wood. Part II: Water steam activation from 850 to 950 °C," BioRes. 9(4), 6831-6840.AbstractPDF
    To acquire activated carbon fiber from phenol-liquefied wood (PLWACF) with better developed pore structure and a high proportion of mesoporosity, the porosity evolution of PLWACF activated at temperatures from 850 to 950 °C by water steam was detected by the physical adsorption of N2 at -196 °C. Results showed that the pore structure was well developed by prolonging the activation time at 850 to 910 °C, and it was easy to obtain PLWACF having exceptionally high surface area (larger than 2560 m2 g-1). However, PLWACF with a specific surface area larger than 3000 m2 g-1 could only be obtained in the late activation stages from 850 to 880 °C. Using this activation process, the mesoporosity was remarkably developed. The mesopore proportion drastically increased with an increase in activation temperature or time, reaching a maximum of 49.5%. The pore size distribution widened as the activation time increased and appeared to accelerate with the use of a higher activation temperature. The mesopore size distribution was enlarged from 2.8 to 5.8 nm.
  • Researchpp 6841-6850Wang, Q., Zhu, Q., Xu, J., and Sun, J. (2014). "Combined mechanical destruction and alkaline pretreatment of wheat straw for enhanced enzymatic saccharification," BioRes. 9(4), 6841-6850.AbstractPDF
    Wheat straw was pretreated by combined mechanical destruction and alkaline pretreatments to enhance enzymatic saccharification. Four strategies were employed to evaluate the potential of wheat straw as a feedstock for fermentable sugar production. The effects of the pretreatments on the substrate morphology, size distribution, chemical composition, and cellulose crystallinity, along with the subsequent enzymatic digestibility, were investigated. Optical microscope images showed that mechanical pretreatment alone resulted in poor fiber defibrillation, wherein samples mostly consisted of rigid fiber bundles, while integrated mechanical destruction and alkaline pretreatment led to relatively good fiber defibrillation. Low temperature NaOH/urea pretreatment can fibrillate the rigid fiber bundles into a relatively loose network and alter the structure of the treated substrate to make cellulose more accessible. The glucan conversion rates were 77% and 95% for integrated mechanical destruction and alkaline pretreatments and mechanical destruction followed by low temperature NaOH/urea and ammonium/urea pretreatments, respectively, after 72 h of enzymatic hydrolysis with enzyme loadings of 10 FPU cellulase per g of oven-dry substrate.
  • Researchpp 6851-6860Han, X., Tang, M., and Deng, Y. (2014). "Preliminary study on pulping of rice straw in tris-(2-hydroxyethyl) ammonium acetate ionic liquid under microwave irradiation," BioRes. 9(4), 6851-6860.AbstractPDF
    This study investigated the pulping process of cooking rice straw in tris-(2-hydroxyethyl) ammonium acetate ionic liquid under microwave irradiation. The optimal processing conditions were determined via othogonal experimentation based on analyses of the effects of the main factors, namely the mass ratio of ionic liquid to rice straw, cooking time, and microwave power, on the cooking of pulp. Those conditions are as follows: mass ratio of ionic liquid to rice straw 5:1, cooking time 30 min, and microwave power 350 W. When subsequent verification experiments were conducted under the conditions above, the pulp yield was as high as 47.28%, the ionic liquid was able to be recycled, and the recovery was as high as 96.9%. The physical properties of the paper confirmed that paper of satisfactory commercial quality could be produced using this technology.
  • Researchpp 6861-6875Ángeles Ramírez, K. A., Arana-Cuenca, A., Medina Moreno, S., Loera-Corral, O., Cadena Ramírez, A., Téllez-Jurado , A. (2014). "Effect of biological and chemical pre-treatment on the hydroylsis of corn leaf," BioRes. 9(4), 6861-6875.AbstractPDF
    Hydrolysis of corn leaf utilizing two treatment sequences was carried out in this study. The first treatment was chemical and involved subjecting the corn leaf to an alkaline pre-treatment and then to a smooth acid hydrolysis. The second consisted of biological delignification using the strain Trametes sp. 44 H88, followed by enzymatic hydrolysis using the enzymatic extract produced by Trichoderma sp. H88. The ligninolytic extract produced by Trametes sp. 44 H88 was used to detoxify the hydrolyzate. The results indicate that biological pre-treatment with delignification is more favorable and improves the subsequent hydrolysis, regardless of whether the hydrolysis is chemical or biological. The chemical treatment sequence obtained 80% conversion of monosaccharides, while the biological treatment sequence resulted in a 87% conversion rate. Finally, the use of the ligninolytic extract for the dephenolization of the hydrolyzate reduced the presence of compounds of phenolic origin by 23%.
  • Researchpp 6876-6887He, W., Jiang, X., Sun, F., and Xu, X. (2014). "Extraction and characterization of cellulose nanofibers from Phyllostachys nidularia Munro via a combination of acid treatment and ultrasonication," BioRes. 9(4), 6876-6887.AbstractPDF
    In this work, α-cellulose was extracted from Phyllostachys nidularia Munro using an acidified sodium chlorite treatment followed by alkali treatments, and cellulose nanofibers (CNFs) were then extracted from α-cellulose via the combination of sulfuric acid (64 wt%) and low-intensity ultrasonication. The results showed that superior CNFs were successfully extracted and their diameters were in the range of 5 to 20 nm. Fourier transform infrared spectroscopy (FTIR) suggested that a majority of the hemicellulose and lignin were removed from the original material and that the chemical constituents of α-cellulose and CNFs were similar. X-ray diffraction (XRD) analysis indicated that the relative crystallinity of CNFs was significantly increased to approximately 69.32% and all specimens presented a typical cellulose I crystal form. Thermogravimetric analysis (TGA) showed that the thermostability of the CNFs was greatly increased.
  • Researchpp 6888-6898Liu, H., Jiang, Z., Zhang, X., Liu, X., and Sun, Z. (2014). "Effect of fiber on tensile properties of moso bamboo," BioRes. 9(4), 6888-6898.AbstractPDF
    Bamboo is a natural bio-composite that has outstanding mechanical properties. Fibers are the structural building block of bamboo. Understanding the effect of fiber area on tensile properties of moso bamboo (Phyllostachys pubescens Mazei ex. H. Lebaie) will shed light on natural efficient design of bamboo. In this paper, fiber area and tensile properties of bamboo were tested on four bamboo slices, and a relationship found between fiber area and tensile properties. The results indicated that fiber volume increased exponentially in the radial direction from the inside to the outside of the culm wall. Bamboo tensile strength and MOE were linearly proportional to the fiber area. Fiber area also influenced bamboo fracture modes.
  • Researchpp 6899-6913Cha, Y. L., An, G. H., Park, Y., Yang, J., Ahn, J. W., Moon, Y. H., Yoon, Y. M., Yu, G. D., and Choi, I. H. (2014). "Partial simultaneous saccharification and fermentation at high solids loadings of alkaline-pretreated Miscanthus for bioethanol production," BioRes. 9(4), 6899-6913.AbstractPDF
    In this study, alkaline pretreatment at a bench scale (15-L capacity) was performed to obtain a higher solid residue for the SSF (simultaneous saccharification and fermentation) of Miscanthus sacchariflorus “Goedae-Uksae 1” (GU) under the following conditions: 1 M NaOH concentration, 150 °C, and 60 min residence time. Compositional analysis and scanning electron microscope analysis revealed the pretreatment to be highly effective for achieving delignification and morphological changes. Spiral impellers were used for the rapid liquefaction of pretreated GU into slurry, and no additional nutrients were added to the fermentation mixture to reduce overall process costs. The SSF was subsequently conducted in a laboratory-scale fermenter (5-L capacity) for 108 to 120 h with 12% and 16% glucan containing pretreated GU. Consequently, 62.8 g/L and 81.1 g/L of ethanol were obtained. Based on these data, the theoretical ethanol yields from 1 kg of GU (dry weight base) were estimated at 164.6 to 171.1 g/L.
  • Researchpp 6914-6923Zhong, Y., and Ren, H. (2014). "Reliability analysis for the bending strength of larch 2x4 lumber," BioRes. 9(4), 6914-6923.AbstractPDF
    A safety analysis for Larch (Larix gmelinii) 2×4 lumber, based on the requirements of Chinese national standards, is presented in this paper. Static, third-point bending tests were conducted using an MTS universal testing machine. The bending strength was adjusted to 15% moisture content (MOR15) and was fitted with three different probability distribution models. The best fitting MOR15 model for Larch 2×4 lumber possessed lognormal distribution. Furthermore, a procedure for calculation of a reliability index ) was developed using the first-order second-moment method. Results of reliability analysis indicated that the reliability indexdecreased nonlinearly as both the design value of bending strength increased and the reduction of live to dead load ratio ). Finally, it was suggested that the design values for the bending strength of Larch 2×4 lumber were 18.4 MPa for grade SS, 11.6 MPa for grade No.1, 12.7 MPa for grade No.2, and 10.3 MPa for grade No.3, to meet the target reliability level.
  • Researchpp 6924-6937Zhao, Z., and Yu, S. (2014). "Bacterial cellulose and silica hybrid reinforcements in poly-(vinylidene fluoride) composite membranes," BioRes. 9(4), 6924-6937.AbstractPDF
    Poly-(vinylidene fluoride) (PVDF), which has a low surface energy, is a common material used for ultrafiltration (UF) membranes. Bacterial cellulose (BC) contains a large number of hydroxyl groups, which has a strong water holding capacity. It can improve the hydrophilicity of PVDF. By means of in-situ composite preparation, with the introduction of tetraethoxysilane (TEOS) as silicon source from the outside of BC and polymerizing, hybrid reinforcing material comprised of BC and silica (BC/SiO2) was achieved which were catalyzed by different acids. After that, by means of a phase separation method with PVDF, composite membranes (PVDF/BC/SiO2) were prepared. Visible spectrophotometry, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to investigate the characteristic of BC/SiO2 hybrids. The structure and properties of composite membranes were also investigated. After catalysis by acid, SiO2 particles uniformly adhered to the surface of BC fibers, which resulted in small pores being formed preferentially in the interface of PVDF composite membranes, while reducing the finger-like pores. At the same time the retention of the composite membranes were improved. So both the properties and structure were improved due to the presence of certain BC/SiO2 hybrid reinforcements.
  • Researchpp 6938-6949Borz, S. A., Ignea, G., and Vasilescu, M. M. (2014). "Small gains in wood recovery rate when disobeying the recommended motor-manual tree felling procedures: Another reason to use the proper technical prescriptions," BioRes. 9(4), 6938-6949.AbstractPDF
    An efficient wood harvesting activity aims to fully recover wood as a measure to increase the profit, but safety prescriptions should be obeyed each time when harvesting operations are performed. A study was carried out in three forest compartments in order to determine whether the actual tree felling procedures match the recommended ones and, if not, to compare how the used practices may affect the wood recovery when felling trees using a conventional undercut. The study yielded significant statistical differences between the recommended and used cuts dimensions, as well as significant differences between the procedures used by three studied work teams. The general trend was to make deeper cuts and smaller openness when performing undercuts. Since one reason for such tree felling procedures may be the increment of wood recovery rate, we conducted a comparative analysis between the potential volume loss in the two mentioned scenarios, and only small differences were found; this should discourage the use of such tree felling techniques. The present estimates suggest that the potential volume loss was 0.89 to 1.20% of the harvested volume, yielding small gains in terms of wood recovery if compared to that of 1.74 to 3.17% corresponding to the recommended practices.
  • Researchpp 6950-6967Hou, X., Sun, F., Zhang, L., Luo, J., Lu, D., and Yang, Y. (2014). "Chemical-free extraction of cotton stalk bark fibers by steam flash explosion," BioRes. 9(4), 6950-6967.AbstractPDF
    Cotton stalk bark fibers (CSBF) were extracted by steam flash explosion, completed within 0.09 s, and the extracted fibers were compared with those obtained by conventional alkaline treatment. Results indicate that the optimum steam pressure was 2.5 MPa when steaming time was set to 2 min for extracting CSBF. Under the optimized conditions, the obtained CSBF had a cellulose content of 72%, length of 48 mm, fineness of 45 dtex, crystallinity index of 68, moisture regain of 8%, water retention of 98%, and tensile strength of 2.4 cN/dtex, which were similar to results obtained by conventional alkaline treatment. Compared with bark of cotton stalks, CSBF had lower moisture regain and water retention, and higher onset decomposition temperature. The results show that moderate steam flash explosion is a chemical-free, quick, and effective method for exploring the industrial applications of bark of cotton stalks as natural cellulose fibers.
  • Researchpp 6968-6980Celis, R., Torres, M., Valenzuela, P., Ríos, R., Gacitúa, W., and Pesenti, H. (2014). "Characterizing cellulosic fibers from Ulex europaeus," BioRes. 9(4), 6968-6980AbstractPDF
    Information on the morphological and physical properties of biofibers is necessary to support the mechanical understanding of the biological design of plants, as well as for the development of new technology that adds value to non-traditional bioresources, such as those based on Ulex europaeus fibers. Ulex europaeus fibers were extracted through a chemical pulping process at 170 °C and with 40 g/L NaOH. The dimensions of the fibers produced were 0.97 ± 0.1 mm in length and 13 ± 2 μm in diameter. Pressed fiber paper sheets were made to evaluate their mechanical properties. Burst and tear indices of 1.2 mN/kg and 8.6 Nm2/kg, respectively, were recorded. The values obtained did not compare well to fiber paper sheets from Pinus radiata, presumably due to the significant amount of non-structural elements of wood present in the samples and the lower length of Ulex europaeus fibers, which resulted in lower tensile strength. Additionally, nanoindentation tests were conducted to assess the hardness and elastic modulus of the fibers, obtaining average values of 0.84 GPa and 9.23 GPa for the stem, respectively. These values were significantly lower than those of industrial biofiber, perhaps due to the lower morphogenic maturity of Ulex europaeus fibers compared to other traditional sources of fiber.
  • Researchpp 6981-6997Niu, F., Yao, S., Nie, S., Qin, C., Zhu, H., and Wang, S. (2014). "Optimum conditions for the removal of Cr(VI) using modified eucalyptus bark," BioRes. 9(4), 6981-6997.AbstractPDF
    The aims of this study were response surface modeling and optimization of Cr(VI) removal from solution using formaldehyde-modified eucalyptus bark. A high removal rate of Cr(VI) was achieved under the conditions of low adsorbent dosing quantity and high initial concentration of Cr(VI). Analysis of variance showed a high multiple coefficient of determination (R2=0.9875), adjusted determination coefficient (R2Adj=0.9714), and the good second order regression equation. The initial concentration of Cr(VI) was 40.15 mg/L, adsorbent dosing quantity 3.40 g/L, and initial reaction pH 2.78, and the largest removal rate was 99.998% under the optimum reaction conditions. Langmuir and Freundlich isothermal models described well adsorption of Cr(VI) by the modified stringy bark. Adsorption kinetics studies showed that the adsorption was controlled by multiple factors, dominated by chemical adsorption. The adsorption was found to be spontaneous and endothermic, with △G0 < 0, △H0 > 0, and △S0 > 0. Adsorption of Cr(VI) by formaldehyde-modified stringy bark was partly controlled by REDOX reactions. The adsorbents were characterized by SEM and FTIR.
  • Researchpp 6998-7017Lin, C., Qiao, S., Luo, W., Liu, Y., Liu, D., Li, X., and Liu, M. (2014). "Thermodynamics, kinetics, and regeneration studies for adsorption of Cr(IV) from aqueous solutions using modified cellulose as adsorbent," BioRes. 9(4), 6998-7017.AbstractPDF
    Cellulose adsorbent was prepared by ATRP grafting of glycidyl methacrylate onto a cellulose backbone with subsequent functionalization with ethanediamine, and then used for the removal of Cr(VI) from aqueous solution. Batch experiments were carried out to investigate the effects of initial pH and initial Cr(VI) concentration on the adsorption performance. The optimum pH for adsorption of Cr(VI) ranged from 2 to 3, and the maximum uptake of Cr(VI) from solution was 500 mg/g at pH 3.0 and 50 °C. Langmuir and Freundlich isotherms were applied to the adsorption process, and the thermodynamic parameters were calculated. The results showed that the sorption process to be feasible, spontaneous, and endothermic. Kinetics studies revealed that the pseudo-second-order kinetic model fitted well with the experimental data and the intra-particle diffusion was not the only rate-determining step for Cr(VI)sorption onto adsorbent. The cellulose adsorbent before and after Cr(VI) adsorption were characterized using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). Regeneration of cellulose adsorbent loaded with Cr(VI) can be achieved by treating with 2.0M NaOH.
  • Researchpp 7018-7026Grigorev, I. V., Grigorev, G. V., Nikiforova, A. I., Kunitckaia, O. A., Dmitrieva, I. N., Khitrov, E. G., and Pásztory, Z. (2014). "Experimental study of impregnation birch and aspen samples," BioRes. 9(4), 7018-7026.AbstractPDF
    An experimental study of wood impregnation was implemented by applying centrifugal methods. The impregnants were a 10% aqueous solution of potassium chloride and a 2% aqueous solution of borax. Birch (Betula pendula) and aspen (Populus tremula) wood samples in different moisture content were tested. The impregnation time in the centrifugal device were 30 seconds repeated 21 times, and the samples were measured after every 30 seconds. The experimental results were fitted to a nonlinear filtration law, which indicated that the centrifugal wood impregnation was dependent on wood species, wood moisture, rotational speed, and radius. Determination of rotational speed and centrifuge radius for impregnating aspen and birch at varying lengths and humidity under conditions of the nonlinear impregnant filtration law can be done using the example charts that were developed and presented in this study.
  • Researchpp 7027-7040Wang, R., Wang, J., Xu, R., Fang, Z., and Liu, A. (2014). "Oil production by the oleaginous yeast Lipomyces starkeyi using diverse carbon sources," BioRes. 9(4), 7027-7040.AbstractPDF
    Producing microbial oils via oleaginous yeast fermentation has drawn broad attention in the biodiesel industry. The oleaginous yeast Lipomycesstarkeyi utilizing diverse carbon sources including glucose, xylose, glycerol, and willow wood sawdust (WWS) hydrolysate for the biosynthesis of oils in its cell growth were investigated in this study. High carbon/nitrogen ratios within the glucose media significantly increased the lipid content of Lipomycesstarkeyi cells and modified the fatty acid composition of lipids, promoting the accumulation of C16:0 fatty acids and saturated fatty acids (C16:0 and C18:0). The accumulation of C18 fatty acids (C18:0, C18:1, and C18:2) and unsaturated fatty acids (C16:1, C18:1, and C18:2) was restricted. When crude glycerol and WWS hydrolysate were used as the sole carbon sources for L. starkeyi fermentation, the dry cell weight, lipid content, and lipid productivity were 9.1 g/L, 46.2%, and 4.2 g/L, respectively, for glycerol, and 8.2 g/L, 42.7%, and 3.5 g/L, respectively, for the hydrolysate solution. This study provides useful information for producing oils with L. starkeyi fermentation using glycerol and WWS hydrolysate as the primary or secondary carbon substrates.
  • Researchpp 7041-7058Omar, F. N., P. Mohammed, M. A. P., and Samsu Baharuddin, A. (2014). "Effect of silica bodies on the mechanical behaviour of oil palm empty fruit bunch fibers," BioRes. 9(4), 7041-7058.AbstractPDF
    The surface of oil palm empty fruit bunch fibres contains embedded silica bodies or protrusions. The mechanical contribution of the protrusions towards the integrity of the fibres is still not clearly investigated. In this work, 2D and 3D finite element simulations on the surface and cross section of the fibres, respectively, were performed. The information for the models was obtained from scanning electron microscopy analysis and mechanical tests for the silica body characteristics and elastic modulus, respectively. Different silica bodies arrangements and the effect of spiked geometry of the silica bodies was investigated using 2D models. Cohesive zone modelling was introduced to simulate damage or debonding between the interface of silica bodies and fibre. A 3D finite element model was later developed consisting of a silica body (sphere) embedded halfway in the matrix. The numerical results showed that the 2D model was sensitive to critical stress compared to silica bodies spiked geometry, arrangement of silica bodies on the fibre surface, and cohesive energy. On the other hand, the results showed that for 3D models with thicknesses larger than 0.2 mm, the effect of the silica bodies on the elasticity of the fibre was not significant.
  • Researchpp 7059-7072Abdul Majid, R., Ismail, H., and Mat Taib, R. (2014). "Effects of polyethylene grafted maleic anhydride on the mechanical, morphological, and swelling properties of poly (vinyl chloride)/epoxidized natural rubber/kenaf core powder composites," BioRes. 9(4), 7059-7072.AbstractPDF
    The effects of polyethylene grafted maleic anhydride (PE-g-MA) on the properties of poly (vinyl chloride)/epoxidized natural rubber (PVC/ENR) kenaf core powder composites were studied, with four different loadings of kenaf core powder (5, 10, 15, and 20 phr). The tensile properties indicated that the strength and elongation at break of the composites exhibited an increase for samples with PE-g-MA. Morphological analysis using a scanning electron microscope (SEM) showed better dispersion of kenaf fiber with the addition of PE-g-MA and less kenaf powder agglomeration. Furthermore, the swelling index indicated that composites with PE-g-MA showed lower toluene absorption than composites without PE-g-MA.
  • Researchpp 7073-7085Shangguan, W., Zhong, Y., Xing, X., Zhao, R., and Ren, H. (2014). "2D model of strength parameters for bamboo scrimber," BioRes. 9(4), 7073-7085.AbstractPDF
    Experiments were performed to test the compressive strength of bamboo scrimber board at different grain angle directions. Investigation of test samples allows for the identification of the correlation between compression failure stress and various failure mechanisms at different grain angles. The results of the experiments showed that the density of bamboo scrimber influenced compression failure stress linearly. A new approach to describe the failure stresses of bamboo scrimber was proposed. The density was introduced as a model parameter to describe compressive properties at varying angles of grain. In comparison to a one-dimensional model, there was much less relative error between predicted values and measured values by this 2D model. This report aims to improve the precision of existing strength models for various grain angles and to provide a competing method for the practical use of bamboo scrimber.
  • Researchpp 7086-7098Luppold, W. G., and Bumgardner, M. S. (2014). "Changes in the international trade balance of U.S. hardwood products from 1990 to 2013," BioRes. 9(4), 7086-7098.AbstractPDF
    We examine U.S. exports and imports of hardwood products from 1990 to 2013. These products include logs, lumber, veneer, chips, molding, cooperage, plywood, and flooring. The values of hardwood products exported and imported have fluctuated over the years but have generally increased. More substantial changes have occurred with the countries and regions receiving U.S. exports, as well as with those importing into the United States. The primary region receiving U.S. hardwood log and lumber in 1990 was Western Europe, but today, China is the most important market. East Asia has been the most important source region for U.S. hardwood plywood imports, but the specific sources have shifted from Indonesia and Taiwan in 1990 to China today. The overall balance of U.S. hardwood product trade has remained positive for most of the years examined, with the United States having a comparative advantage in exporting logs and lumber. In contrast, the United States has a comparative disadvantage in hardwood plywood exports.
  • Researchpp 7099-7108Csordós, D., Németh, R., and Bak, M. (2014). "Variation of colour properties between and within new Robinia varieties with enhanced growing rates from different sites," BioRes. 9(4), 7099-7108.AbstractPDF
    This research analysed the colour properties of new Robinia varieties with enhanced growing rates. The investigations comprised new Robinia varieties grown on different East Hungarian sites. The colour coordinates were determined in the international CIELab system. The mean colour values of the wood of the different varieties did not show significant differences. However, the standard deviation of the measured colour coordinates showed higher values in the case of almost all varieties with high growth rates, compared to the controls (non-fast-growing). The higher colour variegation of most of the fast-growing varieties is attributed to some genetic property, as the standard deviation is independent from the mean annual ring width and the production site.
  • Researchpp 7109-7118Xiao, W., Pang, A., Wang, X., Liu, J., and Han, L. (2014). "Separation and analysis of microwave-assisted liquefied products of corn stover," BioRes. 9(4), 7109-7118.AbstractPDF
    Corn stover was successfully liquefied by microwave heating at 160 °C with ethylene glycol (EG) used as the solvent and sulfuric acid as a catalyst. Gas chromatography and mass spectrometry (GC-MS) data indicated that methyl esters, including 3-(2-methyl-1,3-doxolane-2-yl) propionic acid methyl ester (PAME), levulinic acid isopropyl ester (LAE), methyl laurate, and methyl palmitate were the major degradation compounds, in addition to EG derivatives in the liquefied product of corn stover (LPCS). For high value-added utilization of LPCS, solvent extraction was applied to characterize the components and to separate it into useful fractions. After being dispersed in water, the water-soluble fraction of the LPCS was then extracted with organic solvents, including hexane, chloroform, diethyl ether, and ethyl acetate. Levulinic acid isopropyl ester showed the highest distribution in chloroform and ethyl acetate, while the lowest in hexane and ether. Levulinic acid isopropyl ester was selectively enriched to 28.76% and 43.65% by sequential extraction with chloroform and ethyl acetate, respectively, in accordance with the quantitative analysis.
  • Researchpp 7119-7127Ge, Y., Li, D., and Li, Z. (2014). "Effects of lignosulfonate structure on the surface activity and wettability to a hydrophobic powder," BioRes. 9(4), 7119-7127.AbstractPDF
    The wettability of a solid material is very important in many applications, such as food, agrochemical formulations, and cosmetics. Wettability can be improved by adding surface active agents, especially biocompatible surfactants derived from biomass. In this work, the surface activity (ability to lower the surface tension of an aqueous solution) and wettability toward a hydrophobic powder by a series of sodium lignosulfonates (NaLS) synthesized with different degree of sulfonation (QS) and weight-average molecular weights (Mw) were investigated by measuring the surface tension and contact angle. The results demonstrated NaLS with a larger Mw or lower QS had higher surface activity. Conversely, the wettability of the NaLS aqueous solution toward difenoconazole powder showed a reverse trend, i.e., NaLS with a smaller Mw or higher Qs improved the wettability to difenoconazole. The surface activity and wettability was controlled by the varying densities of the NaLS molecules at the water to air interface or the solid/liquid interface, which was dependent on the molecular structure of NaLS.
  • Researchpp 7128-7140Montibeller, V. W., Vandenberghe, L. P. S., Amore, A., Soccol, C. R., Birolo, L., Vinciguerra, R., Salmon, D. N. X., Spier, M. R., and Faraco, V. (2014). "Characterization of hemicellulolytic enzymes produced by Aspergillus niger NRRL 328 under solid state fermentation on soybean husks," BioRes. 9(4), 7128-7140.AbstractPDF
    This manuscript describes the analysis of xylanase production by Aspergillus niger NRRL 328 in solid state fermentation (SSF) of soybean husks. A maximum value of extracellular xylanase activity of approximately 950 U g-1 was achieved after 96 h. Proteomic analyses performed on the enzymatic mixture responsible for the maximum value of xylanase activity in SSF revealed the presence of two xylanases. This xylanolytic mixture was partially purified and characterized. It followed Michaelis-Menten kinetics towards xylan, with a KM of 7.92 ±0.97 mg xylan/mL and a Vmax of 262.2 ± 27.8 g L-1 s-1. The optimum pH for the enzyme is 5.3, and the optimal temperature is 50 °C. The enzyme retains 100% of its activity at 40 °C for at least 1 month. It shows very high stability in a broad pH range, with a half-life of 40 days at pH 5.3, pH 6.0, pH 6.5, pH 7.0, and pH 8.0.
  • Researchpp 7141-7151Gaff, M., and Matlák, J. (2014). "Modification of veneers by lamination and steaming for the purpose of increasing 3D moldability," BioRes. 9(4), 7141-7151.AbstractPDF
    The focus of this work was to determine the 3D moldability of veneers on circular test pieces treated with steam plastification. These results were compared with results acquired from pieces laminated with three different types of laminating foils with thicknesses of 80, 100, and 125 µm before proper 3D molding. The purpose of test piece lamination was to change the degree of pre-stress and move the neutral plane into the laminating foil, which actually works as a flange. Results acquired from sets of test pieces modified by steam plastification and lamination were compared with the results acquired for the set of test pieces without any treatment. To determine the effects of wood type, the results obtained with beech wood of 0.5-mm thickness were compared with the results acquired from birch wood of 0.5-mm thickness using two types of spherical stamping tools with 20-mm and 40-mm diameters for molding the test pieces. The final examined characteristics were the means of attachment of the test pieces; i.e., the effect of loose attachment and attachment with a hold. The characteristic of maximum deflections was examined during 3D-molding. To measure the listed results, a testing appliance was specially designed and constructed.
  • Researchpp 7152-7161Yan, L., and Morrell, J. J. (2014). "Effects of thermal modification on physical and mechanical properties of Douglas-fir heartwood," BioRes. 9(4), 7152-7161.AbstractPDF
    The flexural properties, mass losses, and moisture behavior of thermally modified Douglas-fir pretreated with boron or glycerol were examined. Pretreatments were associated with slight, but not significant, reductions in modulus of rupture (MOR) and modulus of elasticity (MOE) of Douglas-fir at different thermal treatment levels. Boron pretreatment had the greatest effect on MOR. MOR of non-pretreated and boron-treated samples increased slightly at the initial stage of thermal treatment and then decreased with rising temperature and time. The MOR of glycerol-treated samples decreased with increasing temperature and time. The thermal treatments employed had no significant effect on MOE. Both temperature and pretreatments improved anti-swell efficiency. Further studies are underway to characterize the nature of the chemical changes associated with the thermal modification process.
  • Researchpp 7162-7175Long, J., Xu, Y., Wang, T., Shu, R., Zhang, Q., Zhang, X., Fu, J., and Ma, L. (2014). "Hydrothermal depolymerization of lignin: Understanding the structural evolution," BioRes. 9(4), 7162-7175.AbstractPDF
    The structural evolution of Panicum virgatum lignin during hydrothermal depolymerization was investigated. Product distribution from various temperatures was studied using gas chromatography-mass spectrometry (GC-MS ) and gel permeation chromatography (GPC) analysis. The physical-chemical properties of initial lignin, tetrahydrofuran soluble fraction, and char were also comparatively characterized by elemental analysis, scanning electron microscopy (SEM), thermogravimetry (TG), and Fourier transform infrared (FT-IR) spectroscopy. Results showed that both the depolymerization and repolymerization were significantly temperature-dependent. The undesired char formation becomes obvious when the temperature is greater than 180 °C. Further investigation demonstrated that H lignin is the most accessible for hydrothermal depolymerization, whereas S lignin is the most recalcitrant. Moreover, under the thermal effect and the dissolution of the subcritical water, the basic structure of lignin was first collapsed and then further decomposed into low-molecular weight products by the fracture of ether bonds, accompanied by char formation after repolymerization and dehydration.
  • Researchpp 7176-7188Qin, Z., Zhang, Q., Gao, Q., Zhang, S., and Li, J. (2014). "Wettability of sanded and aged fast-growing poplar wood surfaces: II. Dynamic wetting models," BioRes. 9(4), 7176-7188.AbstractPDF
    The dynamic wettability of adhesive on sanded and aged wood surfaces was measured using the sessile drop method. Four different models were used to evaluate and compare the wetting process. It was shown that the wettability of freshly sanded wood and aged wood both decreased compared to the control wood. There was no evidence of change in wettability with increasing grit number. Aging reduced the wettability of the wood surface. The coefficients of determination (R2) for all four models were over 90%, and that of the Modified model was 99%. The models can be used to accurately describe the adhesive wetting process. The wettability of water and adhesive on the fresh surface were different, and the wettability of the adhesive increased as grit number increased. On the contrary, the wettability of water decreased as grit number increased, and the same trend was found for the water and the adhesive on the aged wood surface. Advantages and disadvantages were found for each model, but the Modified model needs to be verified by additional experiments.
  • Researchpp 7189-7197Ordaz-Díaz, L. A., Rojas-Contreras, J. A., Rutiaga-Quiñones, O. M., Moreno-Jiménez, M. R., Alatriste-Mondragón, F., and Valle-Cervantes, S. (2014). "Microorganism degradation efficiency in BOD analysis formulating a specific microbial consortium in a pulp and paper mill effluent," BioRes. 9(4), 7189-7197.AbstractPDF
    Pulp and paper mills are a major source of pollution, generating huge amounts of intensely colored effluent that goes to the receiving end of a wastewater treatment plant. The biochemical oxygen demand test (BOD5) relies heavily on the microorganism metabolic capability added to the test as seeding material. The seeding material in the testing is obtained from sewage sampling or from commercial sources. Specific organic pollutants that are present in paper and pulp mill effluent can only be degraded by specific microbes; therefore, common sewage or synthetic seed may lead to erroneous BOD5 estimations. In this study, specific microbial species were selected to evaluate their degradation efficiency, both individually and in combination. The microorganisms selected in the formulated seed exhibit BOD5 in a reproducible and synergistic manner. The formulation of this specific microbial consortium can be used to develop bioremediation strategies.
  • Researchpp 7198-7208Nayeri, M. D., Tahir, P. M., Taghiyari, H. R., Alias, A. H., Karimi, A., Abdullah, L. C., Bakar, E. S., and Namvar, F. (2014). "Medium-density fiberboard made from kenaf bast and core: Effects of refining pressure and time on specific gas permeability," BioRes. 9(4), 7198-7208.AbstractPDF
    Studies concerning the production of medium-density fiberboard (MDF) with kenaf as an alternative fibrous material were carried out as an attempt to provide a sustainable and viable source for this lignocellulosic product. This work sought to evaluate the influence of fiber properties (including fiber length, width, wall thickness, and lumen diameter that affect aspect and flexibility ratios) on specific gas permeability in medium-density fiberboard (MDF) made from kenaf bast and core fibers, respectively. Results showed that MDF panels produced from kenaf core had significantly lower permeability than those produced from kenaf bast. This lower permeability was primarily related to the higher flexibility ratio of kenaf core fibers, which provided more surface connection area between fibers, resulting in higher integration among fibers. Lower ash and extractive contents of the core section also improved the efficiency of resin and the connection of fibers to each other; eventually lower permeability was observed in panels made from kenaf core. A high correlation was found between gas permeability and water absorption.
  • Researchpp 7209-7221Ramasamy, S., Balakrishna, H. S., Selvaraj, U., and Uppuluri, K. B. (2014). "Production and statistical optimization of oxytetracycline from Streptomyces rimosus NCIM 2213 using a new cellulosic substrate, Prosopis juliflora," BioRes. 9(4), 7209-7221.AbstractPDF
    Prosopis juliflora is a drought-resistant evergreen spiny tree that grows in semi-arid and arid tracts of tropical and sub-tropical regions of the world. Dry pods of P. juliflora are a rich source of carbon (40% total sugar) and nitrogen (15% of total nitrogen) and so can be considered as a good substrate for the microbial growth. The present study was mainly focused on the utilization of these pods for the production and statistical optimization of oxytetracycline (OTC) from Streptomyces rimosus NCIM 2213 under SSF. The spectral characterization and chemical color reactions of purified OTC by UV, FTIR, 1H NMR, 13C NMR, and HPLC revealed that the structure was homologous to a standard sample. A central composite design with 26 trails yielded the following critical values of supplements to be added to the dry pods: maltose (0.125 g/gds), Inoculum size (0.617 mL/gds), CaCO3 (0.0026 g/gds), and moisture content (74.87%) with the maximum OTC yield 5.02 mg/gds.
  • Researchpp 7222-7233Ouyang, L., Huang, Y., and Cao, J. (2014). "Hygroscopicity and characterization of wood fibers modified by alkoxysilanes with different chain lengths," BioRes. 9(4), 7222-7233.AbstractPDF
    As the main raw material for fiberboard, the hygroscopicity of wood fibers is of great concern. In this study, three alkoxysilanes with different chain lengths—methyl trimethoxy silane (MTMS), octyl trimethoxy silane (OTMS), and dodecyl trimethoxysilane (DTMS)—were used respectively to treat wood fibers to reduce their hygroscopicity and surface hydrophilicity. After alkoyxilane properties were evaluated, the chemical structures, surface groups, and morphology and distribution of alkoxysilanes within modified wood fibers were characterized using scanning electron microscopy (SEM) coupled with energy-dispersed X-ray analyzer (EDXA), Fourier Transform Infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The study found that after modification, the moisture adsorption rate of wood fibers had decreased and the surface hydrophobicity of the fibers had been promoted. The fibers modified with MTMS adsorbed the least amount of moisture. The study also found that while hydrolyzed silane penetrated into wood fibers and reacted with their chemical components, long chains of the silane hindered the degree of that penetration.
  • Researchpp 7234-7242Carvalho, A. G., Zanuncio, A. J. V., Vital, B. R., Carneiro, A. C. O., and da Silva, C. M. S. (2014). "Colorimetric and chemical changes in pre-hydrolyzed strand board particles of pine and eucalyptus," BioRes. 9(4), 7234-7242.AbstractPDF
    Changing wood color with physical treatment is an alternative method to avoid the use of chemicals harmful to the environment. However, despite this advantage, there are few studies on the chemistry and colorimetry of pre-hydrolyzed wood. The objective this research was to evaluate the content of extractives, lignin and holocellulose, lightness (L), red matrix (a*), yellow matrix (b*), saturation (C), and tonality angle (H) on strand board particles of pre-hydrolyzed pine and eucalyptus. Strand board particles measuring 23 x 90 x 0.30 mm in width, length, and thickness, respectively, were pre-hydrolyzed at 130, 150, and 170 °C during 7 or 21 minutes. The temperature had a significant effect on the chemical composition of wood. The pre-hydrolysis temperature of 170 °C resulted in higher chemical modifications. The pre-hydrolysis reduced the equilibrium moisture content of pine and eucalyptus particles, especially at 170 °C. Color modification due to pre-hydrolysis varied according to treatment conditions. Pine particles were more resistant color changing than the eucalyptus particles.
  • Researchpp 7243-7256Chen, H. X., Wang, C. Z., Ye, J. Z., Zhou, H., Tao, R., and Zhang, Y. S. (2014). "Inhibitory effect of the ethyl acetate fraction of ethanol extract from Rhus verniciflua Stokes wood on the activity of mushroom tyrosinase," BioRes. 9(4), 7243-7256.AbstractPDF
    Solvent extracts of Rhus verniciflua Stokes wood were made using decompressing inner ebullition, and a Box-Behnken design was used to optimize extraction conditions to produce an extract that inhibited tyrosinase activity. The chemical compositions and inhibition rates were determined in extracts made with petroleum ether, ethyl acetate, n-butanol, and an aqueous fractionation. The ethyl acetate fraction had the highest total phenolic content and inhibition rates. The main flavonoids in this fraction were 0.531% fisetin, 7.582% fustin, 0.848% sulfuretin, and 0.272% butein. The effects of the extract on the monophenolase and diphenolase activity of mushroom tyrosinase were studied using the Lineweaver-Burk equation to determine the effect of the extract on inhibition of tyrosinase activity. The results showed that the extract inhibited both the monophenolase and diphenolase activity of the enzyme. The IC50 of the ethyl acetate extract was 308 μg/mL, with the lag period of the enzyme being obviously lengthened; it was estimated to be 2.45 min in the absence of the inhibitor and extended to 9.63 min in the presence of 500 μg/mL of extract. The ethyl acetate extract acted as a mixed type inhibitor. The KI was less than the KIS, which demonstrates that the [ESI] is less stable than [EI], suggesting that the extract could easily combine with free enzyme in the enzyme catalysis system, thus affecting enzyme catalysis on the substrate.
  • Researchpp 7257-7266Yuan, N., Zhang, J., Lu, J., Liu, H., and Sun, P. (2014). "Analysis of inhalable dust produced in manufacturing of wooden furniture," BioRes. 9(4), 7257-7266.AbstractPDF
    To provide an in-depth understanding of preventing occupational diseases and improving working conditions, characteristics of inhalable dust were studied. The results showed that total dust concentration (TDC) from mechanical sanding, portable planning and sanding, putty sanding, and painting sanding with inadequate exhaust ventilation were higher than occupational exposure limits (OELs). The more the furniture material was sanded and the worse the dust exhaust apparatus, the higher the TDC was. The TDC from portable planer sanding and dry sanding and putty sanding was in the range from 8.4 mg/m3 to 8.7 mg/m3 and from 5.3 mg/m3 to 8.4 mg/m3, respectively. The TDC from mechanical sanding and painting sanding was in the range from 4.4 to 6.4 mg/m3 and from 3.4 mg/m3 to 4.9 mg/m3, respectively. More than 90% suspended particulate matter in their TDC had a PM10 in all aforementioned results. The sanding procedure produced 6.7% to 8.2% free silica in the total particulate matter, in addition to wood dust, putty dust, or painting dust. Heavy metals in dust from putty sanding and painting exceeding the OELs were lead (Pb; > 0.3 mg/m3) and cadmium (Cd; > 0.01 mg/m3). There was a large amount of granular grinding material, cluster putty, planar painting dust, and a small amount fibroid wood dust in the dust from putty sanding and painting sanding.
  • Researchpp 7267-7277Yang, T., He, W., Wang, S., and Song, X. (2014). "H2O2 oxidation of corncob holocellulose as a dry-strength additive for paper," BioRes. 9(4), 7267-7277.AbstractPDF
    Corncob, an underutilized agricultural byproduct, was used as the raw material to make a dry-strength additive for paper. Corncob was ground into 80, 100, 150, and 200 mesh powder. The powder was treated with sodium chlorite to remove lignin, and the resulting holocellulose was modified with hydrogen peroxide. The influences of oxidation time, concentration of hydrogen peroxide, dosage of paper strength agent, and the dosage of aluminum sulfate on the paper properties were studied. The results indicate that the oxidized corncobs holocellulose can improve the tensile index, burst index, and folding endurance of paper. Compared with control paper, when the concentration of hydrogen peroxide was 0.9%, the tensile index, burst index, and folding endurance were increased by 24.2%, 14.1%, and 463.8%, respectively. The particle size of raw material, dosage of strengthening agent or aluminum sulfate greatly influences paper properties. Scanning electron microscopy (SEM) analysis showed that the combination between the fibers was improved after adding the strengthening agent, thus improving the strength of the paper. The results can provide a new method for value-added use of corncob.
  • Researchpp 7278-7287Edama, N. A., Sulaiman, A., Abd-Rahim, S. N., Hamid, K. H. K., and Busu, Z. (2014). "Characterization of waste clay from palm oil mill effluent and enzyme immobilization study for cassava saccharification process," BioRes. 9(4), 7278-7287.AbstractPDF
    Waste clay recovered from palm oil mill effluent (POME) was characterized and used as an enzyme-supporting material for the cassava saccharification process. The clay was treated by the Soxhlet extraction method to remove the residual oil and then characterized using a BET surface area analyser, XRF, XRD, FTIR, TGA, and FESEM. The chemical analysis showed that the sample had a high amount of CaO (93%) with a minor content of SiO2 (1.378%) and Al2O3 (0.707%), with a surface area of 1.15 m2/g. The XRD analysis revealed the major mineral presence to be calcite, as confirmed by FESEM analysis. The FTIR results also attested to the presence of a calcite phase and carbonate groups. To study the performance of the waste clay for enzyme immobilization application, the recovered waste clay was further used as an enzyme supporting material for enzyme immobilization in the cassava saccharification process. Results showed that the enzymes were successfully encapsulated and gave the highest immobilization yield of 70% with 2% clay concentration. In addition, the encapsulated enzymes also enhanced the reusability, where the enzyme retained 32% of its activity after seven cycles of saccharification processing.
  • Researchpp 7288-7298Yang, L., Liu, H., Cai, Y., Hayashi, K., and Wu, Z. (2014). "Effect of drying conditions on the collapse-prone wood of Eucalyptus urophylla," BioRes. 9(4), 7288-7298.AbstractPDF
    Collapse is considered one of the most severe defects that can occur during the drying of eucalyptus, resulting in drying degradation. Liquid tension is one of the reasons for the collapse. Some transient-collapse cells can be recovered upon the disappearance of liquid tension, when moisture content is reduced during the drying process. How to control collapse and help its recovery are key factors of drying technology. This supports the introduction of a kind of sequential drying technology to the drying process. Thus, several intermittent drying procedures were used in this study. Measurements of shrinkage and collapse were made on Eucalyptus urophylla under continuous drying as well as several kinds of intermittent drying. Key factors of the intermittent drying schedule, observed for their effect on collapse recovery, were the length of the drying periods and temperature during the intermittent periods. The microstructure of collapse under different drying schedules was examined at the cellular level using scanning electron microscopy (SEM). This confirmed that intermittent drying conditions can help collapsed cells recover more thoroughly than continuous drying conditions.
  • Researchpp 7299-7310Perrin, J., Pouyet, F., Chirat, C., and Lachenal, D. (2014). "Formation of carbonyl and carboxyl groups on cellulosic pulps: Effect on alkali resistance," BioRes. 9(4), 7299-7310.AbstractPDF
    Ozone bleaching generates carbonyl groups on the cellulose polymer when applied to unbleached kraft pulps. This suggests that pulp fully bleached with a totally chlorine-free (TCF) sequence may contain more oxidized groups than standard elemental chlorine-free (ECF) bleached pulp. A fully bleached pulp was treated with sodium hypochlorite to form oxidized groups (mostly carbonyls) on the pure carbohydrates, which were investigated during subsequent alkaline treatment. Carbonyl groups had a strong impact on color development during alkaline treatment. Among the carbonyls, the keto groups were the most active. This was confirmed by the behavior of carbohydrate model compounds that contained aldehyde, keto, and/or carboxyl groups when subjected to alkaline conditions. A subsequent hydrogen peroxide (P) stage effectively decreased the carbonyl content, which reduced yellowing during alkaline treatment. However, the oxidized cellulose was severely depolymerized. The addition of magnesium sulfate (Mg) into the P stage minimized depolymerization while maintaining some of the carbonyls in the carbohydrates. It is proposed that Mg cations can hinder alkaline β-elimination, possibly by forming a complex with the carbonyl groups.
  • Researchpp 7311-7325Mohd Suhaimi, M. D. S., and Ismail, H. (2014). "Properties of rubber seed shell flour-filled polypropylene composites: The effect of poly(ethylene co-acrylic acid)," BioRes. 9(4), 7311-7325.AbstractPDF
    The effect of adding poly(ethylene co-acrylic acid) (PE-co-AA) in rubber seed shell flour (RSSF)-filled polypropylene (PP) composites on processing, mechanical, water absorption, and morphological properties was studied. The addition of PE-co-AA increased the processing torque in PP/RSSF composites. Furthermore, mechanical properties such as tensile strength, flexural strength impact strength, Young’s modulus, and flexural modulus show significant improvement compared to uncompatibilized composites, while elongation at break is reduced. The scanning electron microscopy (SEM) of tensile fracture specimens revealed that the dispersion of RSSF filler in the matrix improved with PE-co-AA, with fewer agglomerations. Water absorption ability of the compatibilized composites was reduced due to the improved interfacial bonding, which limits the amount of water molecules to be absorbed. PE-co-AA acted as a compatibilizer in PP/RSSF composites. Improvement in the properties of the composites was contributed by homogenization of RSSF particles in the PP matrix and reduction of voids and cracks due to improved interfacial adhesion and bonding between matrix and filler.
  • Researchpp 7326-7335Li, R., Ekevad, M., Wang, J., Guo, X., and Cao, P. (2014). "Testing and modeling of thrust force and torque in drilling recombinant bamboo," BioRes. 9(4), 7326-7335.AbstractPDF
    Recombinant bamboo with a thickness of 15 mm was drilled on a CNC machine. The process parameters considered were spindle speed, feed rate, and diameter of the drill, and the response parameters were thrust force and torque. Mathematical models were developed to establish the relationship between the process parameters and the response parameters. The results showed that the main influence on thrust force came from spindle speed and feed rate. High spindle speed with low feed rate was a combination that minimized the thrust force. The process parameters that have a major effect on torque are the diameter of the drill and the spindle speed.
  • Researchpp 7336-7351Kalliola, A., Asikainen, M., Talja, R., and Tamminen, T. (2014). "Experiences of kraft lignin functionalization by enzymatic and chemical oxidation," BioRes. 9(4), 7336-7351.AbstractPDF
    Linear hydrophilic derivatives are expected to soften lignin and improve its utilization in composite applications. Oxidation by means of laccase in the presence of oxygen was employed in an attempt to functionalize commercial kraft lignin by vanillic acid-PEG ester and ether derivatives. Thielavia arenaria and Melanocarpus albomyces laccases at pH 6 and 8 were used. According to O2 consumption and the increase in molar mass, the tested laccases were active toward the lignin and the vanillic acid derivatives and also formed corresponding phenoxyl radicals. However, homogenous polymerization instead of cross-coupling and functionalization took place. As an alternative, lignin functionalization by the ester derivative by chemical oxidation under alkali-O2 conditions was also tested. Efficient lignin polymerization was observed. However, functionalization was not detected. Interestingly, a clear decrease in lignin glass transition temperature was obtained by an isolation procedure that included freeze-drying. This suggests that functionalization may not be necessary to induce the desired softening effect.
  • Researchpp 7352-7362Zhang, T., Gao, J., Qi, B., and Liu, Y. (2014). "Performance of concrete made with superplasticizer from modified black liquor and polycarboxylate," BioRes. 9(4), 7352-7362.AbstractPDF
    A new kind of retarding polycarboxylate superplasticizer (M20S80) was prepared through the modification of black liquor and polycarboxylate superplasticizer (S) through an Fe2+-H2O2 reaction system. The synthesis process of M20S80 was introduced. Infrared spectrum analysis (FT-IR) was used to investigate the changes in functional groups in M20S80. At the same time, a mixture of LM20S80 was made by mixing black liquor and S at a mass ratio of 1:4 directly at room temperature. In comparison with S and LM20S80, the influences of M20S80 on the properties of concrete were studied. The results indicate that M20S80 had a better water reduction rate in concrete than LM20280 and was close to S under the same conditions. Furthermore, M20S80 had a retarding effect on the early strength development of concrete, but no negative influence on strength after 28 d of curing. Finally, M20S80 with dosages of 0.45% appeared to be more effective in improving the pore structure of concrete.
  • Researchpp 7363-7371Witomski, P., Olek, W., and Bonarski, J. T. (2014). "Effects of white and brown rot decay on changes of wood ultrastructure," BioRes. 9(4), 7363-7371.AbstractPDF
    Fungal decay results in gradual decomposition of compounds of wood cell walls. Mass loss of wood is usually applied to characterize the decay. However, mechanisms of brown and white rot decay are significantly different, resulting in different degradation of components of wood cell walls. Either type of wood decay should differentially influence wood ultrastructure. The traditionally applied descriptors of wood ultrastructure, i.e. crystallinity, the average spacing of the crystal planes and crystallite size, characterize the ultrastructure in an insufficient way. Crystallographic texture analysis was applied in the present study to characterize changes in wood ultrastructure as a result of brown and white rot decay. The Orientation Distribution Function (ODF) was separately determined for wood decayed by brown rot and white fungi and for several levels of mass loss. A series of crystallographic descriptors was derived from the obtained ODFs. The descriptors consisted of texture index, crystalline volume fraction, and skeleton lines of the ODF. The identified crystallographic orientations confirmed different mechanisms of wood decay for brown and white rot fungi. The observations were supported by different rates of changes of the texture index and evolution of crystalline volume fraction.
  • Researchpp 7372-7381Luo, B., Li, L., Xu, M., Liu, H., and Xing, F. (2014). "Analysis of static friction coefficient between workpiece and rubber belt in sanding wood-based panel," BioRes. 9(4), 7372-7381.AbstractPDF
    This study analyzes the critical static friction coefficient (μ0) and the static friction coefficient (μ) between work-piece and rubber belt during sanding medium density fiberboard (MDF) and particle board (PB). The purpose is to provide theoretical support for improving design techniques of sanding machine and choosing appropriate rubber belts for sanding. The results indicate that μ0 is a constant that can be calculated by maximum sanding force (sFMax) and maximum normal force (nFMax). Besides, there is an exponential relationship between intensity of pressure (P) and μ when work-piece is relatively static on a rubber belt. Among all sanding parameters, git size (G) has the greatest influence on μ. In single-factor experiment, we found that the smaller the nFMax is, the greater the μ is (for same rubber belts), but the variation rates of μ and nFMax are coincident. Six types of rubber belts are adopted, and the average μ of No. 1 and No. 4 are greater than others, but average μ of all the belts are lower than μ0, so when use such six types of rubber belts, a hold-down device or vacuum chuck should be equipped on the sanding machine. Patterns of rubber belts have some impact on μ, and appropriate patterns on the surface of rubber belts contribute to higher μ.
  • Researchpp 7382-7388Wang, S., Xie, B., Cheng, Q., Via, B., Xu, M., and Zhao, H. (2014). "The influence of repeated thermal shock on the mechanical properties of mongolia scotch pine and moso bamboo," BioRes. 9(4), 7382-7388.AbstractPDF
    The sharp temperature changes in nature (e.g., forest fires, ice, and snow) can cause mechanical damage to trees and bamboo. The mechanical properties of Mongolia Scotch pine (Pinus sylvestris L. var. mongolica) and Moso bamboo (Phyllostachys edulis) were investigated by a three-point bending test with a repeated thermal shock process (i.e., sudden changes of temperature). The experimental results indicated that the flexural modulus, flexural strength, and deformation work per volume decreased almost linearly with the increased repetition of thermal shock treatment for both Mongolia Scotch pine and Moso bamboo. The damage caused by repeated thermal shock was stronger for Mongolia Scotch pine, as compared to Moso bamboo, under the same thermal shock treatment. Thus, the experimental results provided basic data for engineering applications of Mongolia Scotch pine and Moso bamboo after natural disturbances.
  • Researchpp 7389-7402Xie, Z., Chen, Y., Wang, C., Liu, Y., Chu, F., and Jin, L. (2014). "Effects of bio-based plasticizers on mechanical and thermal properties of PVC/wood flour composites," BioRes. 9(4), 7389-7402.AbstractPDF
    Poly(vinyl chloride)/wood flour (WPVC) composites with dioctyl phthalate (DOP), dibutyl phthalate (DBP), cardanol acetate (CA), or epoxy fatty acid methyl ester (EFAME) were prepared using twin-screw extrusion. The effects of plasticizers on the mechanical, dynamic mechanical, and melt rheological properties of composites and the thermal migration of plasticizers were characterized. The results demonstrated that WPVC/ DBP and WPVC/EFAME composites had better elongation at break; however, composites with bio-based plasticizers exhibited significantly higher impact strength. The morphology indicated that the compatibility between CA and WPVC was poor, while the surface of the composites showed good plasticity with the addition of DBP or EFAME. The PVC matrix with a plasticizer of higher molecular weight exhibited a higher glass transition temperature (Tg). The dynamic rheological test showed that WPVC/EFAME composites had the lowest storage modulus, loss modulus, and complex viscosity, but EFAME migrated more easily from composites than other plasticizers.
  • Researchpp 7403-7426Abd Hamid, S. B., Chowdhury, Z. Z., and Karim, M. Z. (2014). "Catalytic extraction of microcrystalline cellulose (MCC) from Elaeis guineensis using central composite design (CCD)," BioRes. 9(4), 7403-7426.AbstractPDF
    Cellulosic fiber extracted from a non-woody, monocotyledonous species of palm tree trunk (PTT) was hydrolyzed with different concentrations of FeCl3 in the presence of hydrochloric acid. The dissolution properties of the amorphous region of palm tree cellulosic fiber (PTC) can be enhanced in the presence of Fe3+ cations in acidic medium. The independent variables, including temperature (x1), time (x2), and concentration of metal chloride (FeCl3) catalyst (x3), were optimized using central composite design (CCD). Responses were measured in terms of percentage crystallinity (y1) and yield (y2) of the prepared hydrocellulose. Analysis of variance (ANOVA) showed that temperature was the most influential factor for hydrolyzing the amorphous sections of cellulose. Under optimum conditions, the percentage crystallinity (y1) and yield (y2) were 68.66% and 83.98%, respectively. Scanning electron microscopy (SEM) analysis and X-ray diffraction techniques were used to obtain more information about the surface morphology and crystallinity of the prepared microcrystalline cellulose (MCC). Infrared spectroscopy and thermal analysis were performed to observe the effect of hydrolysis on the finished products. It was concluded that the addition of FeCl3 salt in acid hydrolyzing medium can substantially increase the crystallinity of palm tree trunk cellulose with significant morphological changes to yield microcrystalline cellulose (MCC).
  • Researchpp 7427-7443Laguarda Mallo, M. F., and Espinoza, O. (2014). "Outlook for cross-laminated timber in the United States," BioRes. 9(4), 7427-7443.AbstractPDF
    Cross-laminated timber (CLT) is a building system based on the use of massive, multi-layered solid wood panels. Although CLT as a construction system has been successful in Europe, only a handful of CLT projects have been built in the U.S. This manuscript presents the results from qualitative research, carried out with the objective of assessing the market potential and barriers to the adoption of CLT in the U.S. Insights from national and international experts were collected using semi-structured interviews. Topics included perceived benefits and disadvantages of CLT as a construction system, major barriers to its adoption in the U.S., and level of awareness about CLT among the architecture community.
  • Researchpp 7444-7453Chen, N., Zeng, Q., Rao, J., and Lin, Q. (2014). "Effect of preparation conditions on bonding strength of soy-based adhesives via viscozyme L action on soy flour slurry," BioRes. 9(4), 7444-7453.AbstractPDF
    To evaluate the effects of preparation conditions of a 'green' soy-based adhesive (SBA), Viscozyme L was employed to hydrolyze the polysaccharides in defatted soy flour (DSF) for preparing SBAs, and plywood bonded by SBAs with Pinus massoniana veneer was then produced. Effects of enzymolysis pH, temperature, time, and additive amount of the Viscozyme L on water-insoluble substances content (WISC) and bonding strength (boiling-water test) of SBAs were investigated. Results showed that bonding strength increased first then decreased as enzymolysis pH and temperature were increased. WISC decreased with increasing pH and decreased first then increased as temperature increased. WISC decreased and bonding strength improved slowly with the increasing time. Bonding strength improved slowly as additive amount of Viscozyme L increased. WISC decreased as the added amount of Viscozyme L increased and then decreased slowly at the added amount of Viscozyme L of about 50 FBG and beyond. SBAs prepared by Viscozyme L action on soy flour slurry decreased WISC and improved bonding strength. The suitable preparation conditions of SBA for plywood are as follows: enzymolysis pH 5.2, temperature 50 oC, and time 20 min, and the additive amount of Viscozyme L depended on the application condition.
  • Researchpp 7454-7466Salem, M. Z. M., Ali, H. M., and Basalah, M. O. (2014). "Essential oils from wood, bark, and needles of Pinus roxburghii Sarg. from Alexandria, Egypt: Antibacterial and antioxidant activities," BioRes. 9(4), 7454-7466.AbstractPDF
    The essential oils extracted by hydro-distillation of Pinus roxburghii wood, bark, and needles were analyzed by GC/MS, and their antibacterial and antioxidant activities were evaluated. Twenty-two, thirty-one, and twenty-eight compounds were identified in the essential oils of wood, bark, and needles, respectively. The major chemical constituents of wood’s essential oil were caryophyllene (16.75%), thunbergol (16.29%), 3-carene (14.95%), cembrene (12.08%), α-thujene (10.81%), and terpinolen (7.17%). In bark, they were α-pinene (31.29%) and 3-carene (28.05%), and in needles, they were α-pinene (39%) and 3-carene (33.37%). Almost all of the essential oils were active against human pathogen bacteria, and the essential oils from bark and needles were active against the plant pathogen bacteria Ralstonia solanacearum and Pectobacterium carotovorum. Alternatively, Erwinia amylovora was resistant to all tested oils. The total antioxidant activities (TAA%) of the essential oils from wood (82 ± 2.12%), and bark (85 ± 1.24%) were higher than that of tannic acid (81 ± 1.02%), and the TAA% from the essential oil of needles (50 ± 2.24%) was lower than that of tannic acid.
  • Researchpp 7467-7483Then, Y. Y., Ibrahim, N. A., Zainuddin, N., Ariffin, H., Wan Yunus, W. M. Z., and Chieng, B. W. (2014). "Surface modifications of oil palm mesocarp fiber by superheated steam, alkali, and superheated steam-alkali for biocomposite applications," BioRes. 9(4), 7467-7483.AbstractPDF
    In this work, surface modifications of oil palm mesocarp fiber were carried out by using superheated steam, alkali, and consecutive superheated steam-alkali treatments, aiming at modification of fiber’s surface for biocomposite applications. The chemical compositions of fiber were modified after treatments as validated by chemical analysis and Fourier transform infrared spectroscopy. The treated fibers under microscopy observation showed relatively clean, rough, and textured surfaces due to the elimination of impurities and hemicellulose. The crystallinity index and thermal stability of treated fibers were relatively higher than that of untreated fiber as determined by X-ray diffraction and thermogravimetric analyses, respectively. A reduction in water absorption of fiber after treatments was also noted. These results indicated those treatments were effective in modifying the chemical compositions and microstructure of fiber. The treatments also increased the crystallinity and thermal stability, as well as reduced the hygroscopicity of fiber. Those treatments could increase the suitability of fiber to be used in the development of biocomposites.
  • Researchpp 7484-7493Anokye, R., Kalong, R. M., Bakar, E. S., Ratnasingam, J., Jawaid, M., and Awang, K. (2014). "Variations in moisture content affect the shrinkage of Gigantochloa scortechinii and Bambusa vulgaris at different heights of the bamboo culm," BioRes. 9(4), 7484-7493.AbstractPDF
    Malaysia has more than 50 species of bamboo, but few that are utilized commercially. In this study, the physical properties of two of the most popular bamboo species in Malaysia, Gigantochloa scortechinii and Bambusa vulgaris,were evaluated. Moisture content (MC) and shrinkage variation at different height sections at both nodal and internodal categories of the bamboo culm were investigated. A comparison between the height sections and between the nodal and internodal categories, as well as between the species, was carried out. Results indicated a trend of decreasing MC along the culm from base to top, though the difference was not statistically significant. It was also observed that radial shrinkage was slightly greater than tangential shrinkage and was much greater than shrinkage in the longitudinal direction. Nodes appeared to have lower MC and a higher percentage of shrinkage compared to internodes. The shrinkage pattern of the two species of bamboo showed a small radial-to-tangential ratio of 1.15:1, which may have contributed to the dimensional stability of bamboo.
  • Researchpp 7494-7503Luo, B., Li, L., Liu, H., Xu, M., and Xing, F. (2014). "Analysis of sanding parameters, sanding force, normal force, power consumption, and surface roughness in sanding wood-based panels," BioRes. 9(4), 7494-7503.AbstractPDF
    The proper parameters of sanding with an abrasive sanding machine are significant to reduce energy consumption and to improve processing efficiency and quality. The influences of grit size (G), feed speed (U), sanding speed (V), and sanding thickness (Ts) on the sanding force (sF), normal force (nF), arithmetic mean deviation of profile (Ra), power consumption (P), and power efficiency (ε) were analyzed by the orthogonal method in this study. Fuzzy synthetic evaluation (FSE) was adopted to evaluate sF, P, and Ra comprehensively and to determine the optimum sanding parameters. For both medium density fiberboard(MDF) andparticle board(PB), G has the greatest impact on Ra. For MDF, Ts and G have great impacts on sF, G is also the significant factor affecting nF, whereas the significant factors affecting P are U and V. For PB, G, U, and Ts have great impacts on sF, while G and Ts are the significant factors for nF. Significant factors for P are V and Ts. For MDF and PB, when the weight vector (sF, Ra) is (0.3, 0.7), the optimum schemes are G80U3m/minV8.04,9.38,10.74m/sTs0.2,0.3mm and G80U3m/minV9.38m/sTs0.2mm, respectively, and when (sF, Ra) is (0.7, 0.3), the optimum schemes are G80U3,3.72m/minV6.69,8.04,9.38m/sTs0.2 mm and G80U3m/minV8.04, 9.38m/sTs0.2 mm, respectively. Additionally, when the weight vector (P, Ra) is (0.3, 0.7) or (0.7, 0.3), the optimum scheme is G100U2.52m/minV5.35m/sTs0.1 mm.
  • Researchpp 7504-7518Wang, D., Peng, L., Zhu, G., Fu, F., Zhou, Y., and Song, B. (2014). "Improving the sound absorption capacity of wood by microwave treatment," BioRes. 9(4), 7504-7518.AbstractPDF
    Microwave treatment (MW) was used to improve the sound absorption capacity of Pinus sylvestris var. mongolica wood. The effects of the processing parameters such as MW intensity, processing time, and board thickness on the sound absorption of treated wood were investigated. Microstructure changes of the wood after microwave treatment were observed using scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP). It was found that the microwave treatment significantly enhanced the sound absorption capacity of the wood in the middle frequencies. The optimum microwave treatment parameters for Pinus sylvestris var. mongolica wood to achieve an improved permeability are: MW intensity of 18 Kw, board thickness of 30 mm, and processing time of 80 s. The maximum sound absorption coefficient of treated wood was 0.51. Micro-voids were formed in treated wood due to the destruction of the pit membranes, the wood ray cells, as well as the damage in the intercellular layer of the longitudinal tracheids. The number of micro-voids ranging from 7427.6 nm to 400 um increased, resulting in the increase in the air permeability and in sound absorption by the treated wood.
  • Researchpp 7519-7528Dömény, J., Koiš, V., and Zapletal, M. (2014). "Application of microwave treatment for the plasticisation of beech wood (Fagus sylvatica L.) and its densification for flooring system purposes," BioRes. 9(4), 7519-7528.AbstractPDF
    In this study, the application of microwave treatment for wood plasticisation and its densification for flooring system purposes is presented. Microwave plasticisation was carried out using a continuous laboratory device at a frequency of 2.45 GHz, and the testing samples made from European beech (Fagus sylvatica L.) wood were plasticised at different power modes (2 kW, 3.5 kW, and 5 kW). Afterwards, the densification (ratio 50%) of pre-treated samples was performed. The surface temperature (Ts) and average moisture content (MC) of the samples were measured after plasticisation. The results showed the influence of the chosen mode on MC decrease and rapid Ts increase. Thus, the densification of testing samples is affected by different initial conditions that occur during the plasticisation process (MC and Ts). The Brinell hardness (HB) of the densified samples increased by about 57% (2 kW), 103% (3.5 kW), and 83% (5 kW), compared with control samples. These results provide a better understanding of microwave plasticisation usability and its potential optimisation and application in the wood flooring industry.
  • Researchpp 7529-7541Sviták, M., Gašparík, M., and Penc, J. (2014). "Heat resistance of glued finger joints in spruce wood constructions," BioRes. 9(4), 7529-7541.AbstractPDF
    The heat resistance of glued spruce wood was evaluated for different joint types and adhesives. Bending strength, modulus of elasticity, and also fracture evaluation were investigated on glued spruce samples made by the finger-jointed principle. Finger-jointed samples were glued with polyurethane (PUR) and melamine-urea-formaldehyde (MUF) adhesives. Heat loading was realized at temperatures 60, 80, and 110 °C and compared with wood with 20 °C. A static bending test with four-point flexural test was used. Elevated temperature and adhesive type had an important influence on the bending strength. On the other hand, adhesive type had a significant influence on the modulus of elasticity, but elevated temperature had no substantial influence.
  • Researchpp 7542-7553Zhang, J., Yang, H., Jiang, J., and Jiang, X. (2014). "Research on physical and chemical properties of blended bio-oil based on fractionation," BioRes. 9(4), 7542-7553.AbstractPDF
    To improve the properties of bio-oil, a new method was proposed that does not involve introduction of any energy medium. An ether-soluble fraction (ES), a dichloromethane soluble fraction (DCMS), and a dichloromethane insoluble fraction (DCMIS) of bio-oil were obtained using ether and dichloromethane as extraction solvents. The same amount of each fraction (10 g) was blended into bio-oil with a certain quantity of 100 g. The three samples were then placed in sealed vials and heated for 12, 60, and 180 h at both 60 °C and 80 °C in an oil bath. Based on the aging properties of the three fractions, blended bio-oil was prepared using ES and DCMS in certain volume ratio. The total yield of the three fractions combined was around 90 wt%; the weight loss was thought to be due to the volatilization of low molecular weight matter and water during the process of solvent evaporation using a rotary evaporator. The aging test results indicated that the DCMIS fraction had the poorest properties compared with ES and DCMS such as acid number, water content and viscosity. In order to get the best properties of blended bio-oil, the optimal volume ratio of ES/DCMS was 1/2 according to the aging test.
  • Researchpp 7554-7565Wan, H., Wang, X.-M., Barry, A., and Shen, J. (2014). "Recycling wood composite panels: Characterizing recycled materials," BioRes. 9(4), 7554-7565.AbstractPDF
    Downgraded medium density fiberboard (MDF), particleboard (PB), and oriented strandboard (OSB) panels were individually subjected to steam explosion treatment. Downgraded MDF and PB panels were separately treated with thermal chemical impregnation using 0.5% butanetetracarboxylic acid (BTCA). And downgraded PB panels were processed with mechanical hammermilling. The pH, buffer capacity, fiber length, and particle size of these recycled materials were evaluated. After the steam explosion and thermal chemical impregnation treatments, the pH and buffer capacity of recycled urea formaldehyde resin (UF)-bonded MDF and PB furnishes increased and the fiber length decreased. The hammermilling of recycled PB was less likely to break particles down into sizes less than 1 mm2.
  • Researchpp 7566-7578Wang, Y., Lindström, M. E., and Henriksson, G. (2014). "Increased degradability of cellulose by dissolution in cold alkali," BioRes. 9(4), 7566-7578.AbstractPDF
    To enhance the degradability of cellulosic materials for further industrial purposes, different qualities of cellulose were dissolved in cold sodium hydroxide solution and precipitated by lowering the pH with sulfuric acid. The precipitated cellulose was subjected to acidic and enzymatic hydrolysis. The results showed that the precipitated cellulose degraded considerably faster both with enzymes and acid relative to the untreated controls. Important pretreatment parameters that can influence the degradability of the pretreated cellulosic materials were found to include temperature and concentration of the cellulose in NaOH solution. Increasing amounts of cellulose were hydrolysed with decreasing pretreatment temperature; the degradability of the pretreated cellulose increased with decreasing cellulose concentration. The degree of polymerization (DP) also can influence the pretreatment efficiency. Diluted sulfuric acid was able to decrease the DP and enhance the effect of dissolution and precipitation. The results showed that the lower DP of cellulosic materials caused an increase of degradability for the NaOH pretreated samples compared to untreated samples. The NaOH pretreatment was more effective for shorter chain cellulose.
  • Researchpp 7579-7592Coronado, C. J., McConnell, T. E., and Matthews, S. N. (2014). "Economic impacts of timber product outputs in Ohio across timber market regions," BioRes. 9(4), 7579-7592.AbstractPDF
    Input-output models were constructed to describe the economic impacts of timber product outputs in Ohio and its three timber market regions - the Northeast, West, and Southeast - for 2012. Impact Analysis for PLANning was used to describe these impacts in terms of employment, output, and value added based on 1) the total value of outputs delivered to market by each region’s logging sector and 2) a per-unit change in the regionalized delivered value of one million board feet (MMBF) of hardwood sawtimber. Direct impacts of timber products were greatest in the Northeast (for output and value added) and Southeast (for employment). The total economic impacts of timber products in Ohio were 2,880 employees, $287 million in output, and $147 million in value added. The per-unit impact results were more varied due to regional differences in economies and timber price determinants. Employment and output economic impacts per MMBF were both highest in the Southeast. The employment levels directly and indirectly associated with each MMBF in the West were higher than the Northeast. Value added per MMBF was highest in the Northeast across impacts.
  • Researchpp 7593-7605Shenga, P. A., Bomark, P., Broman, O., and Hagman, O. (2014). "3D phase-shift laser scanning of log shape," BioRes. 9(4), 7593-7605.AbstractPDF
    In this paper, a portable scanner to determine the 3D shape of logs was evaluated and compared with the measurement result of a computer tomography scanner. Focus was on the accuracy of the shape geometry representation. The objective is to find a feasible method to use for future data collection in Mozambique in order to build up a database of logs of tropical species for sawing simulations. The method chosen here was a 3D phase-shift laser scanner. Two logs, a birch log with bark, and a Scots pine log without bark were scanned, resulting in 450 cross sectional “images” of the pine log and 300 of the birch log. The areas of each point cloud cross section were calculated and compared to that of the corresponding computer tomography cross section. The average area difference between the two methods was 2.23% and 3.73%, with standard deviations of 1.54 and 0.91, for the Scots pine and birch logs, respectively. The differences in results between the two logs are discussed and had mainly to do with presence of bark and mantle surface evenness. Results show that the shape measurements derived from these methods were well correlated, which indicates the applicability of a 3D phase-shift laser scanning technology for gathering log data.
  • Researchpp 7606-7621Lacoa, U., Velarde, G. J., and Saloni, D. E. (2014). "U.S. biomass opportunities for value-added biomass exports based on the European union renewable energy share targets," BioRes. 9(4), 7606-7621.AbstractPDF
    World energy demand is expected to continue increasing in the coming years. This situation has created a worldwide pressure for the development of alternative fuel and energy sources, pursuing a more environmentally friendly usage of biofuels. The EU has the target of generating 20% of its energy consumption from renewable sources by 2020. Member States have different individual targets to meet this overall target. Meanwhile in the United States, there are about 750 million acres [300 million hectares] of forestland, with slightly more than two-thirds classified as timberland or land capable of producing 20 cubic feet per acre [1.4 m3 per hectare] annually of roundwood. Given these circumstances, this research aimed to understand the U.S. opportunities to export woody biomass based on the targets that the European Union has imposed to its Member States. The data collected allowed several scenario developments by identifying the possible EU’s biomass deficits and U.S.’s capacity to supply the gaps. Considering the physical availability, the U.S. would be able to satisfy between 42 and 48% depending on the energy efficiency scenario. Nevertheless, when considering reasonable biomass prices, only a small portion of the EU demand could be covered by the U.S.
  • Researchpp 7622-7635Ashworth, A. J., Sadaka, S. S., Allen, F. L., Sharara, M. A., and Keyser, P. D. (2014). "Influence of pyrolysis temperature and production conditions on switchgrass biochar for use as a soil amendment," BioRes. 9(4), 7622-7635.AbstractPDF
    Biochars form recalcitrant carbon and increase water and nutrient retention in soils; however, the magnitude is contingent upon production conditions and thermo-chemical conversion processes. Herein we aim at (i) characterizing switchgrass (Panicum virgatum L.)-biochar morphology, (ii) estimating water-holding capacity under increasing ratios of char: soil; and, (iii) determining nutrient profile variation as a function of pyrolysis conversion methodologies (i.e. continuous, auger pyrolysis system versus batch pyrolysis systems) for terminal use as a soil amendment. Auger system chars produced at 600 °C had the greatest lignin portion by weight among the biochars produced from the continuous system. On the other hand, a batch pyrolysis system (400 °C – 3h) yielded biochar with 73.10% lignin (12 fold increases), indicating higher recalcitrance, whereas lower production temperatures (400 °C) yielded greater hemicellulose (i.e. greater mineralization promoting substrate). Under both pyrolysis methods, increasing biochar soil application rates resulted in linear decreases in bulk density (g cm-3). Increases in auger-char (400 °C) applications increased soil water-holding capacities; however, application rates of >2 Mt ha-1 are required. Pyrolysis batch chars did not influence water-holding abilities (P>0.05). Biochar macro and micronutrients increased, as the pyrolysis temperature increased in the auger system from 400 to 600 °C, and the residence time increased in the batch pyrolysis system from 1 to 3 h. Conversely, nitrogen levels tended to decrease under the two previously mentioned conditions. Consequently, not all chars are inherently equal, in that varying operation systems, residence times, and production conditions greatly affect uses as a soil amendment and overall rate of efficacy.
  • Researchpp 7636-7652Chen, S., Wang, Z., Fang, K., Fan, G., Peng, W., and Song, J. (2014). "Impact of dilute sulfuric acid pretreatment on fermentable sugars and structure of bamboo for bioethanol production," BioRes. 9(4), 7636-7652.AbstractPDF
    Moso bamboo (Phyllostachys edulis) is an important source of lignocellulosic materials because of its fast growth, its vegetative propagation, and its easy harvesting. The pretreatment of bamboo with dilute sulfuric acid and the effects on its chemical components and enzymatic hydrolysis were studied, in addition to the fibrous structural properties of pretreated residues by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The results showed that dilute sulfuric acid pretreatment primarily hydrolyzed hemicelluloses and resulted in enhanced cellulose and lignin content in the pretreated solids. The maximum yield of hemicellulose recovery was 81.42% when pretreated with 1.00% sulfuric acid at 150 °C for 30 min, and the enzymatic hydrolysis yield was 79.45% when hydrolyzed for 72 h with an enzyme loading of cellulase 40 FPU/g of cellulose. Under these conditions, the overall sugar yield was 83.36% (cellulose and hemicellulose), with a total of 67.11 g fermentable sugars from 100 g dry bamboo. The results indicated that Moso bamboo underwent considerable changes in its chemical composition and physical properties after acid pretreatment, such as the removal of hemicellulose and lignin, an increase in specific surface area and pore volume, and exposure of internal structure, which enhances the enzymatic hydrolysis of Moso bamboo.
  • Researchpp 7653-7665Cheng, S., Panthapulakkal, S., Ramezani, N., Asiri, A. M., and Sain, M. (2014). "Aloe vera rind nanofibers: Effect of isolation process on the tensile properties of nanofibre films," BioRes. 9(4), 7653-7665.AbstractPDF
    The effect of different physico-chemical treatments used in the isolation process of aloe vera (AV) rind nanofibers on the tensile properties of the nanofiber films were studied to understand the root of the low strength values of these films. In the first stage of the investigation, ground AV rind was subjected to different chemical treatments before mechanical defibrillation. In the second stage, cuticle present in the AV rind was removed before subjecting them to chemical treatment. Nanofiber films were prepared using these defibrillated AV rind pulp fibers, and tensile properties were measured to examine the effect of chemical treatments and the raw material characteristics on the nanofibrillation process. The results showed that tensile values were not affected significantly with the chemical treatments; however, the thick cuticle coated on AV rind had a significant effect on the tensile strength and Young’s modulus of the nanofibre films. The maximum tensile strength and Young’s modulus (234.5 MPa and 12.6 GPa) of AV rind nanofibre films without cuticle were very high compared to the nanofibre films with the cuticle (tensile strength of about 110 MPa and Young’s modulus of 10 GPa). The study also found that mild chemical treatments were sufficient to isolate nanofibres from AV rind. The morphological analyses illustrated that the isolated AV rind nanofibers had a diameter size smaller than 20 nm and a high aspect ratio of approximately 1000 to 1500 or larger.
  • Researchpp 7666-7680Cheng, J., Wang, X., Huang, R., Liu, M., Yu, C., and Cen, K. (2014). "Producing ethanol from water hyacinth through simultaneous saccharification and fermentation with acclimatized yeasts," BioRes. 9(4), 7666-7680.AbstractPDF
    The production rate and yield of ethanol was markedly increased when water hyacinth, pretreated with microwave-assisted dilute acid, was fermented with acclimatized yeasts through simultaneous saccharification and fermentation. Water hyacinth hydrolyzate microwaved with 1% (v/v) dilute sulfuric acid was fermented with the acclimatized mixed yeasts Pichia stipitis and Pachysolen tannophilus at a volume ratio of 1:1. The highest ethanol yield was 0.22 g/g (raw biomass of water hyacinth), which was 76.3% of the theoretical ethanol yield. A maximum ethanol production rate of 0.19 g/(L·h) was obtained after 24 h.
  • Researchpp 7681-7695Chu, Q., Li, X., Yang, D., Xu, Y., Ouyang, J., Yu, S., and Yong, Q. (2014). "Corn stover bioconversion by green liquor pretreatment and a selected liquid fermentation strategy," BioRes. 9(4), 7681-7695AbstractPDF
    Green liquor pretreatments and different liquid-fermentation strategies were tested to establish an effective ethanol production process from corn stover. After pretreatment and enzymatic hydrolysis, 329.7 g of glucose and 126.3 g of xylose were obtained from 1,000 g of dry corn stover. The primary aim of this work was to test the fermentability of the enzymatic hydrolysate of green liquor-pretreated corn stover, for no fermentation has been done on the enzymatic hydrolysate of green liquor-pretreated corn stover before. Three liquid-fermentation strategies, including sequential fermentation, co-fermentation, and co-culture, were carried out and compared to select an appropriate fermentation strategy from green liquor-pretreated corn stover. Among the different liquid-fermentation strategies, sequential fermentation yielded the highest ethanol production (210.7 g ethanol/1,000 g corn stover). Using the sequential fermentation strategy, glucose fermentation by Saccharomyces cerevisiae and ethanol distillation was completed prior to xylose fermentation by Pichia stipitis, so that the separate utilization of glucose and xylose ensured that each fermentation stage used the suitable microorganism, permitting high ethanol yields. Sequential fermentation was thus considered to be the most promising liquid-fermentation strategy for ethanol production from green liquor-pretreated corn stover.
  • Researchpp 7696-7709Xi, X., Yan, J., Quan, G., and Cui, L. (2014). "Removal of the pesticide pymetrozine from aqueous solution by biochar produced from Brewer's spent grain at different pyrolytic temperatures," BioRes. 9(4), 7696-7709.AbstractPDF
    Biochar (BC) produced from brewer's spent grain (BSG) via slow pyrolysis at 300, 400, 500, 600, and 700 °C was characterized and investigated as an adsorbent for the removal of the pesticide pymetrozine from aqueous solution. Batch BSG BCs adsorption experiments were carried out under various conditions (such as pH, pymetrozine concentration, and BC dosage) to adsorb the pymetrozine. The BSG BCs adsorption pymetrozine capacities were increased by 21.4% to 55.5% under pyrolysis temperatures of 300, 400, 500, and 600 °C compared to 700 °C with a pyrolysis time of 2 h and by 19.0% to 52.1% at 4 h. At solution pH values of 2, 4, 6, and 8, the adsorption capacities were increased by 9.6% to 39.5% compared with that at pH 10. A similar adsorption tendency was found for the different BCs dosage. In the first 60 min, BC absorbed 70% to 80% pymetrozine. The Langmuir and Freundlich model were highly correlated with BC adsorption. The magnitude of free energy decreased by 32.2% to 47.3% with increasing temperature. The value of the enthalpy change showed the adsorption to be endothermic. The BSG BC had high efficiency in adsorbing pymetrozine and had great potential to prevent the water pollution and reuse the waste of the beer factory.
  • Researchpp 7710-7720Abdul Khalil, H. P. S., Hossain, Md. S., Rosamah, E., Nik Norulaini, N. A., Peng, L. C., Asniza, M., Davoudpour, Y., and Zaidul, I. S. M. (2014). "High-pressure enzymatic hydrolysis to reveal physicochemical and thermal properties of bamboo fiber using a supercritical water fermenter," BioRes. 9(4), 7710-7720.AbstractPDF
    Bamboo fiber was treated using a high-pressure enzyme hydrolysis process. The process performance was compared with the pulping and bleaching process for bamboo fiber. Several analytical methods, including field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry, and differential scanning calorimetry, were employed to determine the physicochemical and thermal properties of the treated cellulosic bamboo fiber. It was found that the pressurized enzyme hydrolysis treated bamboo fiber had the most uniform morphological structure, along with lowest crystallinity and highest thermal stability. Thus, utilizing high-pressure enzyme hydrolysis is the most effective process for treating fiber to remove non-cellulosic components from the raw material, including lignin, hemicelluloses, and waxy materials.
  • Researchpp 7721-7736Lazim, Y., Salit, S. M., Zainudin, E. S., Mustapha, M., and Jawaid, M. (2014). "Effect of alkali treatment on the physical, mechanical, and morphological properties of waste betel nut (Areca catechu) husk fibre," BioRes. 9(4), 7721-7736.AbstractPDF
    This study aims to determine the properties of waste betel nut husk (BNH) fiber as a potential alternative for reinforcement in polymer composites. The BNH fibres were subjected to alkali treatment using 5% sodium hydroxide. In this work, husk fibres extracted from betel nut fruit were characterized for its chemical composition, tensile properties, morphology, and interfacial shear strength. The cellulose content was increased with alkali treatment. Tensile strength and Young's modulus of BNH fibre dropped drastically with alkali treatment but with improvement in elongation at break of the fibre due to extraction of cementing materials of microfibrils in natural fibre, i.e. lignin and hemicellulose. SEM observations revealed that poor tensile strength and modulus were related to the cell wall thinning and deep pores in BNH fibre due to alkali treatment. Interfacial shear strength (IFSS) of alkali treated fibre was higher as compared to untreated BNH fibre due to the increase in fibre surface roughness with alkali treatment.
  • Researchpp 7737-7748Zhong, Y., Jiang, Z., Shangguan, W.-W., and Ren, H.-Q. (2014). "Design value of the compressive strength for bamboo fiber-reinforced composite based on a reliability analysis," BioRes. 9(4), 7737-7748.AbstractPDF
    The objective of this study was to determine the design value for the compressive strength (CS) for bamboo fiber-reinforced composite (BFRC) based on a reliability analysis. A total of 180 specimens were subjected to static compressive testing. The CS of the BFRC was significantly higher than that of raw bamboo and other bamboo-based composites, and its cumulative probability distribution accorded with a normal distribution. Furthermore, a calculation program of the reliability index (β) was developed by adopting the first-order second-moment method. Results of the reliability analysis indicate that β increases nonlinearly not only with the enhancement of the partial coefficient but also with the live-to-dead load ratio in all the simulation load cases. The simulation load case of the maximum and minimum β is G+LO and G+LS, respectively. To meet the target reliability requirement, it is suggested that the design value of CS for BFRC be 43.247 MPa and the partial coefficient be 2.0.
  • Researchpp 7749-7763Pereira, A. L. S., do Nascimento, D. M., Souza, M. S. M., Cassales, A. R., Morais, J. P. S., de Paula, R. C. M., Rosa, M. F., and Feitosa, J. P. A. (2014). "Banana (Musa sp. cv. Pacovan) pseudostem fibers are composed of varying lignocellulosic composition throughout the diameter," BioRes. 9(4), 7749-7763.AbstractPDF
    Agricultural residues represent a disposal problem and a biomass source for chemical production. Lignocellulosic composition varies in plants as a function of several factors such as physiological age and tissue function. Banana pseudostem is a large biomass resource that is usually wasted, in spite of the possibility that it can be used as a source of organic compounds such as cellulose and hemicelluloses. The aim of this paper is compare the lignocellulosic content and physicochemical properties of different sheaths of Pacovan banana pseudostems. The trunk was divided into four different fractions, from the outermost sheaths to the core of the structure. There was a significant difference between the lignocellulosic compositions of the fractions. The X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry measurements reflected this difference in the sheaths. These results indicate that the Pacovan banana pseudostem cannot be considered to be a uniform biomass, and future approaches to its use as a biorefinery feedstock must consider a preliminary separation of the sheaths prior to chemical extraction of organic components.
  • Researchpp 7764-7781Daragon, G., Trouvé, G., Schönnenbeck, C., and Leyssens, G. (2014). "Recovery of an agro-industrial vinasse by adsorption on different wood materials: Parametric study at laboratory scale," BioRes. 9(4), 7764-7781.AbstractPDF
    Three types of biomasses (miscanthus, spruce, and a mixture of different woodchips species) were tested as low-cost adsorption media for an industrial agro-industrial effluent, typically a vinasse. Influences of effluent dilution, working temperature, and time duration were studied. Kinetic modelling studies of adsorption were proposed. Ratios of adsorption at ambient temperature and without dilution expressed in g of dry vinasse per g of dry biomass were 1.0, 0.85, and 0.65 for miscanthus, woodchips mixture, and spruce, respectively. An increase of the temperature from 10 °C to 50 °C led to a decrease of the vinasse viscosity and favored its penetration in the biomasses. Maximal adsorbance of dry matter of vinasse was obtained at 50 °C for a vinasse viscosity of 20 mPas. Whatever the experimental conditions required during adsorption processes, miscanthus showed the best affinity for the vinasse. Pseudo-second order and intra-particle diffusion model well described the adsorption process. This study indicates that conventional biomasses could be used as natural low-cost adsorbent for by-products such as vinasse.
  • Reviewpp 7782-7925Hubbe, M. A., Park, J., and Park, S. (2014). "Cellulosic substrates for removal of pollutants from aqueous systems: A review. Part 4. Dissolved petrochemical compounds," BioRes. 9(4), 7782-7925.AbstractPDF
    Dissolved petroleum-based compounds, e.g. solvents, pesticides, and chemical reagents such as phenolic compounds, can pose significant hazards to the health of humans and ecosystems when they are released to the environment. This review article considers research progress related to the biosorption and removal of such contaminants from water using cellulose-derived materials. The fact that cellulosic materials show promise in removing such sparingly soluble materials from water lends support to a hypothesis that lignocellulosic materials can be broad-spectrum adsorbents. Also, the hydrophobic character and sorption capabilities can be increased through thermal treatment and the preparation of activated carbons. As shown in many studies, the efficiency of uptake of various petrochemical products from water also can be increased by chemical treatments of the adsorbent. It appears that more widespread adoption of biosorption as a means of removing petroleum-based products from water has been limited by concerns about the used, loaded biosorbent. Disposal or regeneration options that need to be considered more in future research include enzymatic and biological treatments, taking advantage of the fact that the biosorbent material is able to collect, immobilize, and concentrate various contaminants in forms that are suited for a number of packed bed or batch-type degradative treatment systems.
  • Reviewpp 7926-7940Ooi, Z. X., Ismail, H., Abu Bakar, A., and Teoh, Y. P. (2014). "A review on recycling ash derived from Elaeis guineensis by-product," BioRes. 9(4), 7926-7940.AbstractPDF
    Oil palm (Elaeis guineensis) ash is defined as the waste generated after the combustion of oil palm biomass. Malaysia is one of the world’s largest producers and exporter of palm oil in the world, and there is approximately 4 million tonnes of oil palm ash generated annually. It is estimated that the amount of oil palm ash will keep increasing due to the high demand for palm oil globally. Normally, oil palm ash is disposed without any beneficial economic return value. The awareness of this environmental crisis has increased significantly over the past few years. With the evolution of ash utilization strategies, interest in oil palm ash in various research fields has grown. Through the effort of researchers and information available, the properties of the resulting materials are affected by the percentage of substitution and particle size of the oil palm ash. The major challenges in utilizing oil palm ash are discussed in this paper, as are the beneficial effects, which can include reducing the negative environmental impact and the product cost. Although the recycling of oil palm ash is still a new focus of interest, the main thrust of waste management in Malaysia will continue to focus on this kind of research and will attempt to solve the problem of disposal of the ash as well.
  • Reviewpp 7941-7950Sarmin, S. N., Welling, J., Krause, A., and Shalbafan, A. (2014). "Investigating the possibility of geopolymer to produce inorganic-bonded wood composites for multifunctional construction material - A Review," BioRes. 9(4), 7941-7950.AbstractPDF
    Wood-based composites are widely used in consumer products, either in structural or non-structural applications. One of the basic elements for wood-based composites is the binder itself. Recent years have seen great development and trends in the field of eco-friendly binders in wood-based composite. There have been many concerns on the effects of formaldehyde and volatile organic compounds (VOC) released from wood-based products. Researchers have put lot of effort into developing environmental friendly products with enhanced sustainability. Binder materials with a focus on geopolymers (i.e., alumino-silicates) are discussed in this publication. The development and utilization of geopolymeric binders is relatively new in the field of wood-based composites. Up to the present there has been insufficient information regarding the manufacturing conditions and properties of wood-nonwood composite materials prepared using a geopolymeric binder. This paper considers the background of geopolymer materials and the possibilities of producing inorganic-bonded wood composite using geopolymer.
  • Reviewpp 7951-8001Vishtal, A., and Retulainen, E. (2014). "Boosting the extensibility potential of fibre networks: A review," BioRes. 9(4), 7951-8001.AbstractPDF
    Production of paper-based packaging is growing at the present moment and has great future prospects. However, the development of new packaging concepts is creating a demand for an improvement in the mechanical properties of paper. Extensibility is one of these properties. Highly extensible papers have the potential to replace certain kinds of plastics used in packaging. Extensibility is also important for the sack and bag paper grades and for runnability in any converting process. This paper reviews the factors that affect the extensibility of fibres and paper, and discusses opportunities for improving the straining potential of paper and paper-like fibre networks. It is possible to classify factors that affect extensibility into three main categories: fibre structure, interfibre bonding, and structure of the fibre network. Extensibility is also affected by the straining situation and the phase state of the polymers in the cell wall. By understanding the basic phenomena related to the elongation, and by combining different methods affecting the deformability of fibre network, extensibility of paper can be raised to a higher level.