NC State
  • Editorialpp 3811-3814Lindman, B., and Medronho, B. (2015). "The subtleties of dissolution and regeneration of cellulose: Breaking and making hydrogen bonds," BioRes. 10(3), 3811-3814.AbstractPDF
    Cellulose dissolution and regeneration are old topics that have recently gained renewed attention. This is reflected in both applications - earlier and novel - and in scientific controversies. There is a current discussion in the literature on the balance between hydrogen bonding and hydrophobic interactions in controlling the solution behavior of cellulose. Some of the key ideas are recalled.
  • Editorialpp 3815-3817Vaz, S. (2015). "An analytical chemist's view of lignocellulosic biomass," BioRes. 10(3), 3815-3817.AbstractPDF
    Lignocellulosic biomass comprises wood and agricultural residues, which are sources of cellulose, hemicellulose, and lignin (the lignocellulosic fractions), and represents the major biomass source. Each of these types of lignocellulosic fractions has its own particular structural characteristics and chemistry, which can be exploited in chemical analyses. For a general approach, the quality of the biomass used determines the product quality. Therefore, reliable information is required about the chemical composition of the biomass to establish the best use (e.g., most suitable conversion process and its conditions), which will influence harvest and preparation steps. Then, analytical chemistry is required to understand and control these processes, their raw materials, products, and residues.
  • Researchpp 3818-3830Li, X., Yu, H., Sun, D., Jiang, J., and Zhu, L. (2015). "Comparative study of enzymatic hydrolysis properties of pulp fractions from waste paper," BioRes. 10(3), 3818-3830.AbstractPDF
    As a lignocellulosic material, wastepaper is a potential material for ethanol production. However, little research on the enzymatic hydrolysis of wastepaper pulp has been conducted. In this study, the enzymatic hydrolysis of different waste pulp fractions (R80 represents greater than 80-mesh wastepaper pulp, R80-180 represents the range of 80- to 180-mesh wastepaper pulp, and R180 represents smaller than 180-mesh waste paper pulp) were carried out at 50 °C, pH 4.8, for 96 h, with a substrate concentration of 5% (w/v) and cellulase loading of 18 FPU/g cellulose. In terms of the specific surface area, fiber structure, and surface morphology, R80-180 had the highest affinity to cellulase and therefore the highest glucose yield of 80.33%. R180 had the lowest glucose yield (55.36%) because of its high ash content (21.36%), which reduced the adsorption of cellulase to cellulose. The enzymatic hydrolysis of R80 mixed with R80 or R80-180 was also studied. Results indicated that adding R80-180 increased the glucose yield of R80. The highest glucose yield (82.57%) was obtained when 15% R80-180 was mixed with R80. However, the glucose content decreased when R180 was mixed with R80 because of its high ash content.
  • Researchpp 3831-3838Li, R., Guo, X., Ekevad, M., Marklund, B., and Cao, P. (2015). "Investigation of glueline shear strength of pine wood bonded with PVAc by response surface methodology," BioRes. 10(3), 3831-3838.AbstractPDF
    The effects of process parameters (adhesive spread, press time, and applied pressure) on the response parameter (shear strength) of pine wood bonded with PVAc were studied. Response surface methodology was applied for design of experiments and for analysis of results. A mathematical model was developed to establish the relationship between the process parameters and response parameters. The results showed that the major factors were adhesive spread and applied pressure. The shear strength increased as the adhesive spread and applied pressure increased within certain ranges.
  • Researchpp 3839-3851Guo, M., and Bi, J. (2015). "Pyrolysis characteristics of corn stalk with solid heat carrier," BioRes. 10(3), 3839-3851.AbstractPDF
    Pyrolysis of corn stalk with a solid heat carrier was studied under temperatures ranging from 430 to 620 °C. The solid heat carrier used was high-temperature ash from a CFB boiler. The yields of three products and their characteristics were investigated. Moreover, the distributions of sulfur and nitrogen in the products were determined. The results indicate that with increasing temperature, the char yield decreased, gas yield increased, and calorific value of the gas increased from 10.13 to 16.65 MJ/m3. The yield of bio-oil reached a maximum, 14.24 wt.%, at 510 °C. Light-oil in the bio-oil accounted for more than 69.12 wt.%. The elemental composition of the char and char ash were analyzed. The distribution of sulfur and nitrogen in the char decreased to 60.44 and 46.52 wt.%, respectively, depending on the raw materials used. These results provide basic data for the possible industrial application of corn stalk.
  • Researchpp 3852-3864Cai, X., and Blanchet, P. (2015). "Electron-beam curing of acrylate/nanoparticle impregnated wood products," BioRes. 10(3), 3852-3864.AbstractPDF
    This study investigated the feasibility of using an electron beam (EB) process to cure chemically impregnated wood products. Maple wood planks were impregnated with the low-viscosity resins 1,6 hexanediol dimethacrylate (HDDA) and trimethylolpropane trimethacrylate (TMPTA). The addition of nanoparticles into the formulation was also studied. The impregnated wood was then cured by EB irradiation. The EB curing method utilizes highly energetic electrons at a controlled energy level to polymerize and cross-link the polymeric materials. The thermal analysis results of differential scanning calorimetry (DSC) confirmed that the curing of chemically impregnated wood by electron beam radiation was validated. Polymerization exotherms were observed for the neat acrylate resin and formulations of acrylate/nanoparticles impregnated maple samples. No polymerization exothermal peaks were observed for both EB-cured impregnated maple and control maple samples, confirming that EB irradiation can serve as an efficient curing method to polymerize acrylate-impregnated wood products. The surface hardness of the EB-cured impregnated maple wood was improved up to 200%.
  • Researchpp 3865-3873Cui, Y., Chang, J. M., Wang, W. L., Li, B., and Ren, X. Y. (2015). "Preparation of activated carbon using bio-oil phenol-formaldehyde resin," BioRes. 10(3), 3865-3873.AbstractPDF
    High-specific surface area activated carbon with distinct pore texture was prepared using bio-oil phenol-formaldehyde (BPF) resin as the raw material and KOH as the activator for chemical activation. The carbonization process was characterized with thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR).The pore texture was characterized with measurements obtained by N2 adsorption analysis and scanning electron microscopy (SEM). It was found that adding bio-oil to phenol-formaldehyde resin can partly enhance the thermal stability and improve the textural properties of activated carbon. The functional groups of BPF resin gradually disappeared in the carbonization reaction with increasing temperature. The activated carbon prepared by BPF resin with 30%wt bio-oil exhibited the optimal perfomance.
  • Researchpp 3874-3889Withers, J., Quesada-Pineda, H. J., and Smith, R. (2015). "Internal and external barriers impacting non-food cellulosic biofuel projects in the United States," BioRes. 10(3), 3874-3889.AbstractPDF
    Escalating demand, along with EPAct 2005, has led the United States government to assume a twofold leadership approach of energy security and environmental practices. This has initiated several important issues pertaining to cellulosic biofuel production. However, little is known about what is needed for the U.S. to lead long-term renewable energy security, how the US will develop and implement leading environmental energy practices, what supply capabilities and refining technologies are available to produce renewable fuels, and how funding can be used to adopt available technologies. This article examines geographical aspects, operational status, and barriers tending to prevent the successful commercialization of non-food cellulosic ethanol projects in the U.S. from secondary sources. Outcomes of this research can be used to further understand inhibitors that impact the production and commercialization of ethanol from non-food cellulosic sources.
  • Researchpp 3890-3907Ibrahim, M. F., Linggang, S., Jenol, M. A., Yee, P. L., and Abd-Aziz, S. (2015). "Effect of buffering system on acetone-butanol-ethanol fermentation by Clostridium acetobutylicum ATCC 824 using pretreated oil palm empty fruit bunch," BioRes. 10(3), 3890-3907.AbstractPDF
    Change of pH has been identified as the most significant parameter in modulating the transition between the conversions of acids into solvents in acetone-butanol-ethanol (ABE) fermentation by Clostridia. Thus, ABE fermentation at various phosphate buffer concentrations and initial pH values was conducted using pure glucose and sugars derived from pretreated oil palm empty fruit bunch (OPEFB). A higher solvent concentration (2.93 g/L) was obtained in the fermentation using 20 g/L of glucose with buffer compared with one without buffer that produced 1.34 g/L of solvents. Approximately 8.77 and 9.15 g/L of solvents were produced from fermentation using 40 g/L of glucose with and without buffer, respectively. In the latter conditions, at an initial pH of 5.5, 8.77 g/L of solvents was obtained, which was the highest concentration compared to other initial pH values. Increasing the buffer concentration to 0.2 M at an initial pH of 6.0 resulted in acid accumulation of 16.83 g/L but reduced the solvent production to 1.36 g/L. In addition, ABE fermentation using 20 g/L of sugars from pretreated OPEFB produced 2.25 g/L of solvents with a yield of 0.13 g/g, which was comparable with fermentation using 20 g/L of glucose conducted in a buffering system.
  • Researchpp 3908-3921Hu, Z., Que, Y., Gao, Y., Yin, Y., and Zhao, Y. (2015). "Using black liquor from the soda pulping process for protein production by Candida utilis," BioRes. 10(3), 3908-3921.AbstractPDF
    Black liquor produced from pulping with a high value of chemical oxygen demand (COD) and biological oxygen demand (BOD) is highly harmful if discharged into the environment directly. One possible way to decrease the damage to the soil and water is to reuse the organic substances contained in it to cultivate yeasts for producing single-cell proteins (SCP) while reducing the COD. With this in mind, this study is devoted to treatment technology and the comprehensive utilization of black liquor. Various parameters were evaluated, and the COD of black liquor, initial pH, and nitrogen sources had significant influences on biomass and crude protein production. The research resulted in the maximum values of COD removal rate and crude protein production with 78.78 ±3.21% and 1.18 ±0.02 g/L achieved, respectively, under the optimized condition of black liquor concentration (60%), the recruitment of urea (0.5 g/L), initial pH (6.0), temperature (34 °C), shaking speed (180 rpm), and incubation time (36 h). Furthermore, this study provided a potential viable treatment of black liquor and revealed a feasible way to make full use of black liquor for the economical production of SCP.
  • Researchpp 3922-3933Wu, C., Zhou, H., Yang, F., Zhang, Y., and Gao, F. (2015). "Microwave pretreatments of switchgrass leaf and stem fractions to increase methane production," BioRes. 10(3), 3922-3933.AbstractPDF
    The objective of this study was to determine the effectiveness of microwave pretreatments on methane production from two switchgrass tissues (leaf vs. stem). The methane production from the leaf fraction was significantly affected by the microwave final temperature, while production from the stem fraction was affected by the combination of the microwave final temperature and heating rate. Thus, the highest methane yield from the leaf (134.81 mL CH4/g of volatile solids (VS)) was obtained at 100 °C, while the highest yield from the stem (99.35 mL CH4/g VS) was obtained at 150 °C, with a heating rate of 10 °C/min. Although methane production from the leaf fraction was merely enhanced by 9.1% after microwave pretreatments, the time required to reach 80% of ultimate methane production was reduced by 12 days. For the stem fraction, methane production was improved by 5.2% after microwave pretreatment, and the time to obtain 80% of ultimate methane production increased.
  • Researchpp 3934-3947Kvarnlöf, N., and Germgård, U. (2015). "Oxygen delignification of acid sulfite and bisulfite softwood pulps," BioRes. 10(3), 3934-3947.AbstractPDF
    This study discusses alternatives for the production of sulfite pulps cooked to high kappa numbers, and a subsequent oxygen treatment by using the same cation in the cooking and in the oxygen stages. Magnesium was used as a cation during both the cooking and oxygen delignification stages. By using the same cation in the cook and in oxygen delignification, it is theoretically possible to recover filtrates and send them to the chemical recovery system, meaning that the discharge of pollutants will be very low. Acid sulfite and bisulfite pulps at yields between 56 and 57% (kappa number between 50 and 55) were produced and then delignified with oxygen and magnesium hydroxide to a kappa number between 25 to 30. It was found that the delignification process time was shorter and the yield and viscosity increased, compared with delignification to the same kappa number (25 to 30) for a single cooking stage. The tear and tensile strengths were however unchanged, regardless of delignification process used.
  • Researchpp 3948-3962Du, X., Li, S., Li, G., Feng, H., and Chen, S. (2015). "Stress wave tomography of wood internal defects using ellipse-based spatial interpolation and velocity compensation," BioRes. 10(3), 3948-3962.AbstractPDF
    In this paper, a novel stress wave tomography method, using spatial interpolation and velocity compensation, is proposed for the detection of internal defects in wood, based on the measured time of flight data and the assumption that stress waves propagate in straight lines in the cross-sectional area of wood. First, an improved ellipse-based spatial interpolation method is proposed, which could be used to estimate the velocity value of a grid cell by the elliptic affected zones corresponding to the nearby velocity rays. Second, because of the anisotropic property of wood, a velocity compensation method was applied to obtain more accurate input data for spatial interpolation. Then, the internal graph of the cross-section of a wood trunk could be reconstructed by the proposed algorithm. Four wood samples, with different defects, were used to test the proposed tomography method in the experiment. The results showed that the proposed method performed well and was able to resist signal interference caused by the density variation of the defective area.
  • Researchpp 3963-3978Percin, O., Sofuoglu, S. D., and Uzun, O. (2015). "Effects of boron impregnation and heat treatment on some mechanical properties of oak (Quercus petraea Liebl.) wood," BioRes. 10(3), 3963-3978.AbstractPDF
    Heat treatment changes some physical, mechanical, and chemical properties of wood. Inorganic borates have been used as wood preservatives for many years. The aim of this study was to investigate the effects of impregnation chemicals on some mechanical properties (bending strength (MOR), modulus of elasticity (MOE), tensile strength parallel to the grain (TS), compression strength parallel to the grain (CS), and shear strength parallel to the grain (SS)) of heat-treated oak (Quercus petraea Liebl.). For this purpose, the oak wood specimens were impregnated with 5% aqueous solution of boric acid (BA) and borax (BX). Then specimens were heat-treated at 160, 190, and 220 °C for 2 and 4 h. According to the results of the study, borax retention value was higher than boric acid. The bending strength, modulus of elasticity in bending, tensile strength parallel to the grain, and shear strength parallel to the grain decreased due to heat treatment. The highest mechanical strength losses were determined in samples heat treated at 220 °C for 4 h. Generally the mechanical strength losses of samples impregnated with borax were lower than non-impregnated controls and specimens impregnated with boric acid.
  • Researchpp 3979-3986Zhang, L., Liu, S., Wang, B., Wang, Q., Yang, G., and Chen, J. (2015). "Effect of residence time on hydrothermal carbonization of corn cob residual," BioRes. 10(3), 3979-3986.AbstractPDF
    Hydrothermal carbonization is a promising technique for conversion of industrial waste into valuable products. Producing hydrochar from corn cob residual (CCR) in a cost-effective way is key, from an economic standpoint. For this purpose, the effect of residence time in the range of 0.5 to 6 h was studied under the optimal temperature of 250 °C. Results showed that the higher heating value (HHV) of hydrochar increased approximately 40% in comparison to that of the raw material; however, prolonging the residence time beyond 0.5 h had a negligible effect on the HHV increase. Chemical compositions and H/C and O/C ratios of hydrochars revealed a minimal effect of longer residence time. Furthermore, thermogravimetric and derivative thermogravimetric analysis (TG/DTG), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis of hydrochars also verified that the pyrolysis behavior and chemical structure of hydrochars with various residence times were similar.
  • Researchpp 3987-3998Wang, Y., Wang, X., Hu, Z., Li, Y., Deng, S., Niu, B., and Tan, H. (2015). "NO emissions and combustion efficiency during biomass co-firing and air-staging," BioRes. 10(3), 3987-3998.AbstractPDF
    Experiments were carried out in a drop tube furnace to investigate the effects of biomass/coal co-firing and air staging on NO emission and combustion efficiency. NO and CO emissions along the height of the furnace were monitored by a gas analyzer, and the content of unburned carbon (UBC) in fly ash was also tested. Results showed that NO emission from straw or wood combustion only account for 1/3 or 1/2 that from coal combustion, respectively. Under the conditions of biomass co-firing, the increase in blending ratio had a positive effect on the reduction of NO emission and combustion efficiency. Moreover, results of air-staging combustion showed that for coal combustion, air staging notably reduced NO emission and combustion efficiency. For biomass combustion, the effect was slight. Synergetic analysis indicated that there was an optimum biomass co-firing ratio around 0.4, when the positive synergetic effects on reducing NO emission and UBC were the most significant. When the co-firing ratio exceeded this optimum value, further increasing the co-firing ratio had little influence on NO emission and combustion efficiency. After air staging was adopted, the degree of synergetic effect on NO emissions was reduced while that of UBC was increased.
  • Researchpp 3999-4010Šedivka, P., Bomba, J., Böhm, M., and Boška, P. (2015). "Influence of temperature on the strength of bonded joints," BioRes. 10(3), 3999-4010.AbstractPDF
    The objective of this study was to assess the influence of varying temperature on the strength characteristics of joints bonded using three types of one-component PVAc adhesives (i.e., Rakoll Express D3, Titebond II Premium, and Rhenocoll 3W, 4B Plus) that belong to the group of thermoplastic wood adhesives intended for non-construction bonding applications. The measuring procedure was a transverse tensile test for estimation of joint strength. As documented by the test results, a higher joint strength achieved at a higher temperature was achieved again after a gradual increase in the joint temperature from 20 °C to 140 °C and subsequent cooling to the starting temperature. After cooling the joint to the starting temperature, all tested adhesives complied with the minimum strength, namely 10 MPa. The results obtained in this study indicated that the resistance and thus the strength of joints bonded using contemporary PVAc adhesives increases with time.
  • Researchpp 4011-4025Wagner, L., Bos, C., Bader, T. K., and de Borst, K. (2015). "Effect of water on the mechanical properties of wood cell walls - Results of a nanoindentation study," BioRes. 10(3), 4011-4025.AbstractPDF
    The paper presents a nanoindentation study on five different wood species in which the elastic and creep properties of the S2 cell wall layer and the middle lamella were determined. Measurements were carried out at relative humidities (RH) ranging from 10 to 80% as well as underwater. Indentation moduli were found to decrease by about a third in the S2 layer and by about half in the middle lamella between RH of 10 and 80%. Hardness dropped by 50 to 60% in this humidity range in both the S2 layer and the middle lamella. Creep parameters were almost constant up to a relative humidity of 40%, but they increased considerably at higher RH. The most pronounced change of reduced moduli and creep properties occurred between 60 and 80% RH, which is consistent with the expected softening of hemicellulose and amorphous parts of cellulose in this humidity region. Immersion into water resulted in a further decrease of the reduced moduli to about 20 to 30% of their values at 10% RH and to only about 10 to 20% for the hardness. This can be explained by additional softening of the less ordered regions of cellulose.
  • Researchpp 4026-4037Sarto, C., Segura, T. E. S., and da Silva Júnior, F. G. (2015). "Performance of Schizolobium amazonicum wood in bleached kraft pulp production," BioRes. 10(3), 4026-4037.AbstractPDF
    This study aimed to evaluate the characteristics of Schizolobium amazonicum wood, specifically its performance in bleached kraft pulp production and the characteristics of its pulp. Chips of Schizolobium amazonicum and Eucalyptus grandis x Eucalyptus urophylla (reference) were used. The following parameters were evaluated in the wood: basic density, total extractives, total lignin, holocellulose, and fiber morphology. The pulping simulations were carried out in a laboratory digester, with parameters set to obtain pulp with kappa number 19 ± 0.5. Both pulps were bleached in a PFI mill and submitted to physical-mechanical tests. The results showed that S. amazonicum wood has low basic density and higher content of extractives when compared to E. grandis x E. urophylla wood. For pulping, S. amazonicum required higher alkali charge and H factor to achieve the same delignification level of E. grandis x E. urophylla, resulting in a lower yield, pulp with lower viscosity, and higher wood specific consumption. During bleaching, the brightness gain and final viscosity of S. amazonicum pulp were lower than E. grandis x E. urophylla pulp. Moreover, S. amazonicum pulp had worse physical-mechanical characteristics than E. grandis x E. urophylla.
  • Researchpp 4038-4047Xiao, W., Zhang, X., Wang, X., Niu, W., and Han, L. (2015). "Rapid liquefaction of corn stover with microwave heating," BioRes. 10(3), 4038-4047.AbstractPDF
    Microwave heating was applied in the liquefaction of corn stover with polyhydric alcohol to establish a rapid process for converting corn stover into polyols. With ethylene glycol (EG) as liquefacient and 3.5% sulfuric acid as a catalyst, the residue content was reduced to 4.7% after 20 min of microwave liquefaction at 160 °C. Effects of liquefaction parameters on the residue content were investigated. It was found that the reaction temperature had a greater influence on the residue content than the sulfuric acid concentration and reaction time. The liquefied mixture was characterized as complexes of ester and ether type polyols by means of Fourier transform infrared spectroscopy. 3-(2-Methyl-1,3-dioxolan-2-yl) propanoic acid was characterized as the main degradation product of corn stover, besides the large amount of condensation product of EG.
  • Researchpp 4048-4064Semple, K. E., Zhang, P. K., and Smith, G. D. (2015). "Stranding moso and guadua bamboo. Part 1: Strand production and size classification," BioRes. 10(3), 4048-4064.AbstractPDF
    Giant timber bamboos, such as moso (Phyllostachys pubescens) and guadua (Guadua angustifolia) are potentially well-suited to the production of engineered strand-based structural composite building materials. There is no information available for guadua, but moso bamboo is known to produce good-quality, strand-based composites. However, economically viable commercial production of these composites is hindered by the lack of an efficient, automated method for converting culm stock to strands, and very little technical information is available regarding strand production and quality. In this study, moso and guadua culm characteristics and tissue re-saturation behavior likely to affect stranding were measured and compared. Strand size classification and the thickness and width distributions from stranding re-saturated moso and guadua quartered culm pieces using a CAE 6/36 single-blade disk flaker were determined. While node frequency was lower in guadua than in moso, the diaphragms and embedded wall tissue were much thicker and tougher, with strong negative effects on strand quality. When cut to a target thickness of 0.65 mm, moso bamboo produced strand thickness frequency distributions close to those found in sampled mill strands of trembling aspen, while guadua caused high wear on blades and yielded a greater proportion of excessively thick, broken, and very rough strands.
  • Researchpp 4065-4076Yan, J., and Xu, R. (2015). "Reinforced conductive polyaniline-paper composites," BioRes. 10(3), 4065-4076.AbstractPDF
    A method for direct aniline interfacial polymerization on polyamideamine-epichlorohydrin (PAE)-reinforced paper substrate is introduced in this paper. Cellulose-based papers with and without reinforcement were considered. The polyaniline (PANI)-paper composites had surface resistivity lower than 100 Ω/sq after more than 3 polymerizations. Their mechanical strength and thermal stability were analyzed by tensile tests and thermogravimetric analysis (TGA). Fourier transform infrared (FTIR) results revealed that there was strong interaction between NH groups in aniline monomers and OH groups in fibers, which did not disappear until after 3 polymerizations. Scanning electron microscopy (SEM) and field emission (FE) SEM images showed morphological differences between composites using reinforced and untreated base papers. Conductive composites made with PAE-reinforced base paper had both good thermal stability and good mechanical strength, with high conductivity and a smaller PANI amount.
  • Researchpp 4077-4098Chen, H., Han, Q., Venditti, R. A., and Jameel, H. (2015). "Enzymatic hydrolysis of pretreated newspaper having high lignin content for bioethanol production," BioRes. 10(3), 4077-4098.AbstractPDF
    Recovered papers are suitable biomass sources for conversion into sugars that can be used in bioethanol production. However, paper materials with a high lignin content have been found to be recalcitrant to enzymatic hydrolysis. To address this issue, several biomass pretreatment methods were employed to evaluate their efficiency on the conversion of newspaper with high lignin content to sugar. Autohydrolysis, a hot water treatment, was identified to adversely affect sugar conversion, presumably as a result of pore collapse under high-temperature pretreatment. Flexo ink, used in newspaper printing, had no effect on the enzymatic hydrolysis, with or without autohydrolysis. The ink was still detachable after autohydrolysis, as measured by hyperwashing. Compared to untreated newspaper, separate treatments of either mechanical refining or a non-ionic surfactant (sorbitan polyoxyethylene monooleate) improved the sugar conversion by 10% at enzyme dosages of 2 and 8 FPU/g substrate. The combination of both refining and surfactant resulted in the highest sugar conversions, i.e., 46.3%, 56.7%, and 64.1% at 2, 4, and 8 FPU/g enzyme dosages, respectively. Oxidative pretreatment (oxygen, 100 °C) marginally increased the sugar conversion, whereas alkaline and green liquor (NaCO3 and Na2S) pretreatments (at 160 °C) had either no effect or decreased the sugar conversion. Based on the results of the pretreatments, higher pretreatment temperatures of newsprint negatively impacted subsequent enzyme hydrolysis.
  • Researchpp 4099-4109Tian, J., Fu, S., Zhang, C., and Lucia, L. A. (2015). "Tuning solute partitioning coefficients in a biphasic ionic liquid/water system to facilitate extraction of lignin-oxidized aromatics," BioRes. 10(3), 4099-4109.AbstractPDF
    Extraction of aromatic substances obtained during oxidation of lignin with ionic liquids (ILs)-based molecular oxygen was investigated. It was found that virtually no aromatic substances could be directly extracted with organic solvent until water had been added to the system. The amount of extracted substances increased sharply with an increase in the molar ratio of water to ILs. The distribution constants of aromatic monomers between ILs/water and extracting solvent was obtained by Nernst partition function analysis. The constants fitted well to a second order exponential function model (ExpDec2), which indicated that the activity coefficients of reaction products between ILs and extracting solvent could be tuned by water addition. Among the seven organic solvents tested, ethyl acetate was the most effective, on account of its suitable polarity, while temperature more prominently affected extraction efficiency than time.
  • Researchpp 4110-4125Chong, Y. H., Wan Daud, W. R., Poh, B. T., Ibrahim, M., and Leh, C. P. (2015). "Application of photo, peracetic acid, and combination pre-treatments in improving totally chlorine-free bleaching selectivity," BioRes. 10(3), 4110-4125.AbstractPDF
    The application of totally chlorine-free bleaching (TCF) is well recognised for its environmental compatibility. However, its application is restricted in comparison to a chlorine-based bleaching sequence. TCF bleaching produces pulp with relatively lower brightness and strength properties. Oxygen delignification (O-stage) is commonly used as a first bleaching stage; therefore its selectivity influences TCF bleaching performance. In this study, the selectivity of the O-stage and hydrogen peroxide-reinforced O-stage (Op-stage) on tropical hardwood kraft pulp were 0.53 and 0.71, with 37.8% and 55.5% kappa number (Kn) reductions, respectively. The addition of photo pre-treatment prior to the O-stage and Op-stage improved the Kn reduction to 53.7% and 59.2%; consequently the selectivity was enhanced to 1.0 and 0.73, respectively. The Fourier transform infrared spectra showed that photo pre-treatments improved the selectivity by protecting the cellulose from carbonyl-induced degradation. This protective effect was more prominent in the O-stage than the Op-stage. However, the combination of peracetic acid and photo treatment did not further increase bleaching selectivity in either stage. In short, blue light and UV irradiation treatment with or without the prior addition of peracetic acid to ordinary or hydrogen peroxide-reinforced oxygen delignified pulp displayed a similar bleaching effect on the resultant pulp.
  • Researchpp 4126-4136Panda, R., Tjong, J., Nayak, S. K., and Sain, M. M. (2015). "Effect of alkyl phenol from cashew nutshell liquid on mechanical and dry sliding wear behavior of epoxy resin," BioRes. 10(3), 4126-4136.AbstractPDF
    A phenalkamine made from the reaction of alkyl phenol from cashew nutshell liquid (CSNL) and polyamine was added at three different weight percentages (30%, 40%, and 50%) as a diglycidyl ether of bisphenol A (DGEBA) epoxy hardener. This curing agent was compared to a traditional polyamine epoxy hardener. It was observed that an increase in phenalkamine concentration resulted in considerable improvement to impact strength and elongation, which ultimately translated to better wear resistance of the cured epoxy compound. Lancaster–Ratner correlations between mechanical and wear resistance properties were found to be linear. Optical microscope observations were used to understand the wear mechanisms of the cured epoxy materials.
  • Researchpp 4137-4151-Ang, A., Ashaari, Z., Bakar, E. S., and Ibrahim, N. A. (2015). "Characterisation of sequential solvent fractionation and base-catalysed depolymerisation of treated alkali lignin," BioRes. 10(3), 4137-4151.AbstractPDF
    An alkali lignin (OL) with a weight-average molecular weight (Mw) of 11646 g/mol was used to prepare low-molecular weight lignin for resin synthesis. The low-molecular weight lignin feedstock was obtained via base-catalysed depolymerisation (BCD) treatments at different combined severity factors. Sequential fractionation of the OL and BCD-treated lignins using organic solvents with different Hildebrand solubility parameters were used to alter the homogeneity of the OL. The yield and properties of OL itself and OL and BCD-treated OL dissolved in propan-1-ol (F1), ethanol (F2), and methanol (F3) were determined. Regardless of the treatment applied, a small amount of OL was dissolved in F1 and F2. The BCD treatment did not increase the yield of F1 but did increase the yields of F2 and F3. Gel permeation chromatography (GPC) showed that the repolymerization reaction occurred in F3 for all BCD-treated OL, so these lignins were not suitable for use as feedstocks for resin production. The GPC, 13Carbon-nuclear magnetic resonance, and Fourier transform infrared spectroscopy analyses confirmed that the F3 in OL exhibited the optimum yield, molecular weight distribution, and chemical structure suitable for use as feedstocks for resin synthesis.
  • Researchpp 4152-4166Liu, Z. J., Liu, L. P., Wen, P., Li, N., Zong, M. H., and Wu, H. (2015). "Effects of acetic acid and pH on the growth and lipid accumulation of the oleaginous yeast Trichosporon fermentans," BioRes. 10(3), 4152-4166.AbstractPDF
    Acetic acid, one major inhibitor released during the hydrolysis of lignocellulosic biomass, can be utilized by the oleaginous yeast Trichosporon fermentans without glucose repression. The effect of acetic acid on the cell growth and lipid accumulation of T. fermentans under controlled pH conditions was investigated in a 5-L fermentor. Undissociated acetic acid with concentrations of 0.026, 0.052, and 0.096 g L-1 in media contributed to approximately 12-, 24-, and 48-h lag phases, respectively, indicating that undissociated acetic acid is the inhibitory molecular form. The inhibition of cell growth was correlated with undissociated acetic acid concentration. However, acetic acid had little influence on the lipid accumulation of T. fermentans at different pH conditions. The specific glucose consumption rate decreased with increasing acetic acid concentration, but the impact of acetic acid on the specific xylose consumption rate was not pronounced. In addition, the variation of pH and acetic acid concentration had no significant influence on the fatty acid composition of the lipids. Acetic acid showed more severe inhibition under low pH conditions. The reduction of intracellular pH partly explains this inhibitory effect.
  • Researchpp 4167-4177Li, X., Dai, J., Qian, W., and Chang, L. H. (2015). "Prediction of internal defect area in wooden components by stress wave velocity analysis," BioRes. 10(3), 4167-4177.AbstractPDF
    In this study, wooden components torn down from ancient buildings were used as the experimental materials. With methodology based on reverse simulation testing, some artificial holes making up different proportional areas of their cross-section were chiseled and tested with a six-sensor-point stress wave testing device. The results indicated that two-dimensional analog images could be used to judge the internal defects of wooden components qualitatively but did not provide quantitative, accurate determination. By comparing and contrasting the attenuation tendency of stress wave velocities among adjacent sensor points, separated sensor points, and diagonal sensor points, the defect grade of wooden components can be classified. Six variations were chosen as discriminant factors. These were the attenuation coefficients of the stress wave velocities via three propagation paths and the relative proportions of their absolute values. The Mahalanobis distance discrimination model was adopted for the in-grade estimation of the internal defects present in the component’s cross-section. This method had high operability and no misjudgment ratio.
  • Researchpp 4178-4190Deng, S., Wang, X., Tan, H., Li, Y., Hu, Z., and Niu, B. (2015). "Optimization of operating conditions of a household up-draft biomass gasification stove," BioRes. 10(3), 4178-4190.AbstractPDF
    Experiments were carried out with a household up-draft biomass gasification stove to investigate effects of the air distribution method on the performance of the stove. The temperature distribution along the gasifier, the producer gas composition, the stove power, and the thermal efficiency were investigated. Results showed that in the temperature distribution along the gasifier height, the highest temperature was at the bottom oxidation layer of the gasifier, in the range of 950 to 1050 °C. With increasing air quantity through the burner, the time required to boil the water first decreased and then increased, whereas the stove power and thermal efficiency increased and then decreased. The best stove performance was obtained at an optimum air distribution ratio of 0.333 between burner and gasifier air (0.794×10-3 m3/s·kg). When the burner air increased, the flame length above the burner was remarkably reduced and the flame color gradually changed from yellow-red to blue. At the optimum air distribution ratio of 0.333, the flame was blue and stable. The present study provides references for developing a more efficient biomass gasification stove.
  • Researchpp 4191-4203Hao, W., Tang, X., Zeng, X., Sun, Y., Liu, S., and Lin, L. (2015). "Catalytic conversion of glucose to levulinate ester derivative in ethylene glycol," BioRes. 10(3), 4191-4203.AbstractPDF
    A comprehensive, kinetic experiment on the conversion of glucose to 2-hydroxyethyl levulinate ethylene ketal (HLEK), in a cascade of reactions in ethylene glycol, catalyzed by low-concentration sulfuric acid, was conducted. The ethylene glycol/sulfuric acid system was found to be tolerant of a high glucose concentration, and no solid humins were created. At a high initial glucose concentration (30 wt %), an HLEK yield of 27.6% was achieved at a moderate temperature (433 K) after a 330-min reaction with dilute sulfuric acid (0.15 mol/L). In ethylene glycol, more than half of the initial glucose was converted into glucosides within 5 min, and a dynamic equilibrium between these species was achieved; thus, it is reasonable to assume that the ratio of glucosides to glucose was constant (1.35:1) during the entire reaction process. The production of HLEK from glucose via glucosides as a function of the process variables was well-represented by a simplified first-order kinetic model, and the rate expressions were applied to determine the optimum conditions for batch processing.
  • Researchpp 4204-4225Belle, J., Kleemann, S., Odermatt, J., and Olbrich, A. (2015). "Demonstration of strength development in initial wet paper web using Field Emission-Scanning Electron Microscopy (FE-SEM)," BioRes. 10(3), 4204-4225.AbstractPDF
    Various models exist that explain strength development in the wet web. Furthermore the scanning electron microscope (SEM) has been used in the paper industry to characterise cellulosic fibres and paper. The documentation of the initial wet web properties needs very specific requirements for sample preparation. An SEM image shows the sample´s surface, so the wet sample’s water film would cover all fine fibre structures. For this reason the samples must be dried prior to analysis. Freeze drying is a common method that is described to prepare samples for characterisation of single fibres before and after mechanical treatment. In this investigation the structure of the initial wet web was physically fixed by rapid freezing, followed by freeze drying. Afterwards, the samples were analyzed by Field Emission SEM (FE-SEM). The generated images support the hypothesis that fibrils partially extend themselves from the fibre and interact with adjacent fibres.
  • Researchpp 4226-4238Kvietková, M., Gašparík, M., and Gaff, M. (2015). "Effect of thermal treatment on surface quality of beech wood after plane milling," BioRes. 10(3), 4226-4238.AbstractPDF
    This paper deals with the determination of the surface quality of both thermally treated and thermally untreated wood after the plane milling process. The milled surface quality was evaluated on the basis of the arithmetical mean deviation of the assessed profile, Ra. Surface quality measurements were carried out for various milling process parameters, such as tool clearance angles of 15º, 20º, and 25º, cutting speeds of 20, 30, and 40 m/s, and feed speeds of 4, 8, and 11 m/min. A splinter with a uniform thickness of 1 mm was removed from the wood through milling. Based on the results, it can be stated that thermal treatment of wood has no statistically significant impact on roughness. The most significant impact of the monitored factors were associated with feed speed, clearance angle, and cutting speed. The lowest average roughness values were found at 20º clearance angles, a feed speed of 4 m/min, and a cutting speed of 40 m/s. Increases in cutting speed led to a decrease in average roughness, while an increase in feed speed had the opposite effect.
  • Researchpp 4239-4251Lv, P., Almeida, G., and Perré, P. (2015). "TGA-FTIR analysis of torrefaction of lignocellulosic components (cellulose, xylan, lignin) in isothermal conditions over a wide range of time durations," BioRes. 10(3), 4239-4251.AbstractPDF
    This study investigated chemical decomposition of lignocellulosic components in the course of torrefaction under isothermal conditions for durations up to 5 hours. The goal was a better understanding of the behaviour of biomass, at both short and long residence times, which is important for innovation in the chemical and bioenergy industries. Gaseous and solid-phase decomposition products of cellulose, xylan, and two lignins, were studied following torrefaction at three temperatures (220, 250, and 280 °C) for a continuous recording of mass loss and emission of volatiles over 5 hours. Two decomposition stages were revealed for xylan, with a notable release of CO that increased with treatment temperature. 4-O-methyl glucurono-units on the side chains of xylan degraded first, and acetyl groups and macromolecule fragments accounted for the second degradation, starting at 250 °C. The primary production of acetic acid occurred at 280 °C. For the two lignins, decomposition reactions predominated at lower temperatures, while rearrangement prevailed at 280 °C. The emission of phenol was a clear distinction between the two. Cellulose was thermally stable at short times under all treatments, but it decomposed dramatically afterwards, especially at 280 °C.
  • Researchpp 4252-4262Zhang, Y., Yang, R., Wu, Y., Wang, S., Liu, C., Zhong, X., and Wu, J. (2015). "Effect of growth period on cell wall mechanical properties of elephant grass," BioRes. 10(3), 4252-4262.AbstractPDF
    Elephant grass (Pennisetum purpureum Schum.) is a fast-growing native African plant species that produces commercially useful lignocellulosic biomass. It has been used in many countries to replace wood for paper, particleboard, and fiberboard. There is a close relationship between the mechanical properties of elephant grass cell walls and the performance of its products. The objective of this research was to investigate the cell wall mechanical properties at different growth periods of five types of elephant grasses, i.e., P. americanum cv. Tift 23A×P. purpureum cv. Tift N51 (HP), P. purpureum cv. Tift N51 (N51), P. purpureum cv. Huanan (Huanan), P. purpureum cv. Sumu No.2 (Sumu-2), and (P. americanum× P. purpureum) × P. purpureum cv. Guimu No.1 (Guimu-1). The hardness and elastic modulus of the cell walls were investigated by means of nanoindentation. The results showed that the hardness and elastic modulus of these elephant grasses increased as growth period increased. However, the rate of increase varied for the different types of elephant grass, which could help guide the evaluation of the properties of this kind of bio-fiber resource for the production of high-quality biocomposite products.
  • Researchpp 4263-4276Xian, Y., Li, H., Wang, C., Wang, G., Ren, W., and Cheng, H. (2015). "Effect of white mud as a second filler on the mechanical and thermal properties of bamboo residue fiber/polyethylene composites," BioRes. 10(3), 4263-4276.AbstractPDF
    The purpose of this study was to investigate the effect of white mud (WM) on mechanical and thermal properties of bamboo plastic composites (BPCs). Bamboo residue fibers (BRFs) and WM were added as the reinforcement, and high-density polyethylene (HDPE) served as the matrix. The lubricating agent and coupling agent were polyethylene wax and maleated polyethylene (MAPE), respectively. The mixture was used to manufacture BPCs using a twin-screw extruder. The crystal structure and thermal properties of BPCs were investigated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results showed that the particle size of the WM was 700 nm to 50 μm, which are made mainly of calcium carbonate. BPCs with WM significantly increased the flexural and tensile properties, but the impact strength decreased because of the presence of WM. The flexural and tensile strength of composites with 18 wt% BPF were increased by 36.81% and 6.26%, respectively, while the flexural and tensile modulus were increased by 164.29% and 64.33%, respectively. XRD demonstrated the WM had little effect on the crystal structure of BPCs. Compared to BPCs without WM, the T5% of composites with 22 wt% WM decreased by 27.9 °C. As the WM content increased, the crystallinity of the BPCs decreased initially, then increased with increasing WM content.
  • Researchpp 4277-4286Zhou, X., Wang, X., Cao, R., Tao, Y., Xu, Y., and Yu, S. (2015). "Characteristics and kinetics of the aldonic acids production using whole-cell catalysis of Gluconobacter oxydans," BioRes. 10(3), 4277-4286.AbstractPDF
    The characteristics and kinetics of whole-cell catalysis were investigated individually or simultaneously relative to the bio-oxidation of five monosaccharides to corresponding aldonic acids using Gluconobacter oxydans. For individual catalysis, 30 g/L glucose could be consumed completely at 3.21 g/L/h in 8 h, and arabinose was the slowest-consumed at 1.18 g/L/h in 8 h. Among five monosaccharides, the yield of xylonic acid was highest at 90.4%, and about 31.0 g/L xylonic acid could be obtained in 24 h. For simultaneous catalysis, a complex substrate competition appeared in the mixed-aldoses solution. The utilization rate of arabinose, galactose, xylose and mannose were repressed distinctly. And glucose exhibited variable inhibitory effects on the remaining four monosaccharides utilization. Higher concentration of mixed aldoses showed a tendency to minimize the difference of glucose inhibition on arabinose, galactose, xylose, and mannose conversion to corresponding acids. Thus, the total concentration and proportion between various aldoses should be properly controlled for a highly efficient production of aldonic acids from lignocellulosic material.
  • Researchpp 4287-4299Sha, J., Nikbakht, A., Wang, C., Zhang, H., and Olson, J. (2015). "The effect of consistency and freeness on the yield stress of chemical pulp fibre suspensions," BioRes. 10(3), 4287-4299.AbstractPDF
    To study the influence of mechanical treatments on the yield stress of chemical pulp suspensions, a traditional rheometer, coupled with local velocity measurements (ultrasonic Doppler velocimetry), was used to measure the yield stress of two types of commercial chemical pulp suspensions with different freeness values at mass concentrations (consistencies) ranging from 0.5 to 1.5%. Over the range of consistencies tested, the yield stress was found to depend on the consistency through a power law relationship for all tested samples. Moreover, the results showed that as the freeness decreased, the yield stress of hardwood suspensions increased to a maximum value then decreased. This variation in yield stress was also observed in softwood suspensions with mass concentrations above 1%. However, when the consistency was lower than 0.75%, the yield stress of softwood suspensions increased with decreasing freeness.This behaviour can be understood based on the underlying fibre properties of fibrillation, curl, and stiffness, suggesting that fibre morphology plays a significant role on the yield stress of pulp suspensions over the concentration range studied.
  • Researchpp 4300-4314İlçe, A. C., Budakçı, M., Özdemir, S., and Akkuş, M. (2015). "Analysis of usability in furniture production of wood plastic laminated board," BioRes. 10(3), 4300-4314.AbstractPDF
    The objective of this study was to manufacture a lightweight and easily producible wood plastic laminate (WPL) board that could be used in the furniture sector. Eastern beech (Fagus orientalis L.) veneer papels (A) and hollow polycarbonate boards (B), both with a thickness of 4 mm, were laminated in different combinations using polyurethane (PUR) and polychloroprene (PCR) adhesives. The physical and mechanical properties of the WPL boards obtained were determined according to the principles specified in the EN 326-1, EN 317, EN 310, ASTM D1037, and ASTM D1761 standards. Subsequently, the specimens were compared with particle boards (PB), medium density fiberboards (MDF), and okoume plywoods (PW). According to the results, the AABAA, ABABA, and ABBBA combinations of the WPL materials had better physical properties, such as weight, water absorption, and swelling thickness, compared to the other composites. Furthermore, because the WPL materials had a high bending resistance, modulus of elasticity, and nail and screw withdrawal strength, they could be used instead of PB and MDF. The WPL material obtained within the scope of this study are suitable for furniture making.
  • Researchpp 4315-4325Zhu, J., Xue, L., Wei, W., Mu, C., Jiang, M., and Zhou, Z. (2015). "Modification of lignin with silane coupling agent to improve the interface of poly(L-lactic) acid/lignin composites," BioRes. 10(3), 4315-4325.AbstractPDF
    To improve the mechanical properties of lignin-filled poly(L-lactic) composites, three silane coupling agents, 3-aminopropyltriethoxysilane (KH550), γ-glycidoxypropyltrimethoxysilane (KH560), and g-methyacryl-oxypropyltrimethoxysilane (KH570), were treated systematically with different solvents to modify the interfacial connections. The treatment of lignin with 2 wt.% aqueous KH550 solution was proved to be the most successful. Chemical bonding between the filler and the matrix was formed, according to the FTIR spectra. Furthermore, scanning electron microscope images showed that such treated lignin particles dispersed well in the composites. The tensile strength and Young’s modulus of the composite improved significantly from 55.1 and 1589 MPa to 67.0 and 1641 MPa, respectively, with 5 wt.% treated lignin addition. Although its elongation at break decreased from 20.3 to 12.4% after 5 wt.% of the treated lignin was added, it was still better than that of poly(L-lactic acid) without any additive (10.3%).
  • Researchpp 4326-4338Pérez-Sariñana, B. Y., León-Rodriguez, A. D., Saldaña-Trinidad, S., and Pathiyamattom Joseph , S. (2015). "Optimization of bioethanol production from coffee mucilage," BioRes. 10(3), 4326-4338.AbstractPDF
    A response surface methodology with 2k full factorial design was applied to obtain optimum conditions for bioethanol production using coffee mucilage (CM) as the substrate and Saccharomyces cerevisiae NRRL Y-2034 as the inoculum. CM is an agro-industrial residue mainly composed of simple sugars; the product yield and productivity process were analyzed with respect to the fermentation, pH, temperature, and the initial sugar concentration. Employing the following predicted optimum operational conditions attained the highest bioethanol production: pH 5.1, temperature 32 °C, and initial sugar concentration 61.8 g/L. The estimated bioethanol production was 15.02 g/L, and the experimental production was 16.29 g/L ± 0.39 g/L, with a bioethanol yield of 0.27 g/L and a productivity process of 0.34 g/Lh. Glycerol was the predominant byproduct of the fermentative metabolism of S. cerevisiae. The response surface methodology was successfully employed to optimize CM fermentation. In the fermentative processes with yeast, optimizing the conditions of the culture medium is needed to fully exploit the potential of the strains and maximize the production of bioethanol.
  • Researchpp 4339-4349Ahmad Sharif, N. F., Abd Razak, S. I., Wan Abdul Rahman, W. A., Mat Nayan, N. H., Rahmat, A. R., and Yahya, M. Y. (2015). "Preparation and characterization of cassava leaves/cassava starch acetate biocomposite sheets," BioRes. 10(3), 4339-4349.AbstractPDF
    Biocomposite packaging sheets made of cassava leaves (CL) and cassava starch acetate (CSA) were successfully prepared in this study, and using the surface impregnation method, the sheets were able to obtain desirable properties. The CL sheets were impregnated with CSA at various concentrations to improve the sheets’ performance. This newly developed packaging material exhibited low moisture uptake and had a viable tear index value when the CSA impregnation level was 6%. Moreover, the sheets’ properties were comparable to that of available paper or plastic sheets, having low moisture uptake, good wetting time and tear strength, smooth sheet formation, and enhanced thermal stability. Using agro-based materials from cassava plants for packaging materials could reduce the dependency on paper- and plastic-based packaging. Suitable utilization of this material includes as bag, carton and wrap.
  • Researchpp 4350-4359Abd Razak, S. I., Ahmad Sharif, N. F., Mat Nayan, N. H., Muhamad, I. I., and Yahya, M. Y. (2015). "Impregnation of poly(lactic acid) on biologically pulped pineapple leaf fiber for packaging materials," BioRes. 10(3), 4350-4359.AbstractPDF
    Newly developed packaging paper made of biopulped pineapple leaf fiber (PALF) and poly(lactic acid)(PLA) was studied. PALF packaging sheets were solvent impregnated with PLA at different concentrations in order to improve their moisture barrier and mechanical performance. With the impregnation of PLA at a concentration of 4%, the packaging material exhibited a low moisture uptake and a high tear index. An electron micrograph of the sample at 4% impregnation revealed uniform and packed PLA reversed microsphere morphology. These results suggest that surface coating via biodegradable polymers, such as PLA, may be utilized for manufacturing packaging materials in industrial applications. This new packaging material could reduce the dependency on wood-based paper and plastic-based packaging.
  • Researchpp 4360-4374Motamedi, H., Hedayatkhah, A., and Varzi, H. N. (2015). "Improvement of the hydrolysis and fermentation of rice straw by Saccharomyces cerevisiae by ammonia-based pretreatments," BioRes. 10(3), 4360-4374.AbstractPDF
    This work aimed at improving the hydrolysis and fermentation processes of rice straw through different ammonia-based pretreatments to aid in bioethanol production. For this purpose, pretreatment was performed at 70 °C for 12 h, followed by enzymatic hydrolysis at 50 °C for 24 h and 72 h using 15 FPU cellulase and 30 CBU cellobiase. The best hydrolysis yield, based on the production yield and rate, for the 24-h digestion period was samples that had been soaked in methanolic aqueous ammonia (SMAA), with 72% of the theoretical maximum. However, for the 72-h digestion period, soaking in ethanolic aqueous ammonia (SEAA) was the best method, with 88% yield. In the case of ethanol production after 24 h, the SMAA pretreatment and SSF resulted in the highest yield at 72%. However, after 72 h of simultaneous saccharification and fermentation (SSF), SMAA-pretreated rice straw showed a yield of 85%, while the SEAA-pretreated sample resulted in a noteworthy yield of 89% of the theoretical maximum. However, with regard to the production yield and rate and pretreatment cost, the best method for ethanol production was judged to be the SMAA with 5% methanol, particularly after 24 h of SSF.
  • Researchpp 4375-4390Shi, Y., Belosinschi, D., Brouillette, F., Belfkira, A., and Chabot, B. (2015). "The properties of phosphorylated kraft fibers," BioRes. 10(3), 4375-4390.AbstractPDF
    The properties of phosphorylated kraft fibers, including their flame retardancy and behavior in water, such as electrical charge and swelling capacity, were investigated in this study. Two different phosphorus contents and three forms of phosphorylated fibers (ammonium, acid, and sodium) were analyzed. All types of phosphorylated fibers exhibited high char formation and limiting oxygen index (LOI) values, indicating good flame retardancy. In particular, the ammonium form exhibited the best flame retardancy behavior and the highest LOI value. The charge density and swelling capacity of the kraft fibers were significantly increased by phosphorylation. Alkaline treatment following the phosphorylation reaction further increased the water retention value (WRV) and surface charge of the kraft fibers. Compared to unmodified kraft fibers, the phosphorylated fibers had lower absolute values of the negative zeta potentials, and these values were less affected by conductivity.
  • Researchpp 4391-4402Qian, L., Li, R., Zhou, L., Liu, Y., Yu, M., Xiong, F., Liu, S., and Hao, X. (2015). "Preparation of biomorphic TiO2 ceramics from rattan templates," BioRes. 10(3), 4391-4402.AbstractPDF
    In this work, biomorphic ceramics were produced from various rattan templates, and sol infiltration was used with vacuum/positive pressure technology. Finally, the samples were sintered to form TiO2 ceramics with a rattan microstructure. Through X-ray diffraction (XRD), thermogravimetric (TG) data, dimensional variation analysis, and scanning electron microscopy (SEM) images of biomorphic ceramics, the results of this experiment showed that the times of sol-gel infiltration were decreased due to use of the vacuum/positive pressure technology. In order to further supply the TiO2 content and fill the pyrolysis gaps in the charcoal/TiO2 composites sintered at 800 °C, it was necessary to repeat the sol-gel process. In the transverse section, ceramics for the rattan templates without the rattan edge, more perfect biomorphic features were achieved. Conversely, deformations occurred along the transverse section of the ceramics for the templates made with the rattan edge. Meanwhile, the fracture phenomenon took place along the ceramic axial section. The main reason for deformation and fracture was that the anisotropic structure of the template was stressed during the sintering process. Furthermore, the micrometer-sized pores were found in the ceramics along the axial section because of the removal of the charcoal templates.
  • Researchpp 4403-4410Durmaz, S., Yildiz, U. C., and Yildiz, S. (2015). "Alkaline enzyme treatment of spruce wood to increase permeability," BioRes. 10(3), 4403-4410.AbstractPDF
    In this study, spruce sapwood was administered an alkaline enzyme treatment to improve the flow of wood liquid so that more preservative chemicals could be injected. Spruce wood is recognised as a refractory wood species. Pit membranes play an important role in liquid flow. In this study, an alkaline pectinase enzyme was applied to remove the pectin layer on the torus of the pits and margo. After enzymatic treatment, the pectin layers on the pit membrane were removed. When samples were investigated by both scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), it was evident that pit membranes were destroyed and the permeability increased. In addition, no noteworthy weight loss was observed.
  • Researchpp 4411-4440Morrison, B., and Golden, J. S. (2015). "An empirical analysis of the industrial bioeconomy: Implications for renewable resources and the environment," BioRes. 10(3), 4411-4440.AbstractPDF
    An empirical analysis was undertaken to quantify the utilization of the primary, first-generation agriculture and forestry feedstocks within the industrial bioeconomy. Institutional policies and incentives, and their role in driving the bioeconomy are also explored. In doing so, we present a detailed analysis of global agricultural and roundwood forestry production, including both intermediate and final uses. In addition to deciphering the internal flows of commodities within the bioeconomy, we present the spatial distribution of key industrial bioeconomy feedstock crops and their influence within the global economy, including flows in exportation and importation across ten geographical regions. Finally, along with the many advantages for industrial biofeedstocks, there are also environmental trade-offs. The results from this examination will equip researchers, industries, and governments with a superior ability to address the multi-dimensional feedbacks and synergies of the bioeconomy, as well as predict potential areas of risk and those that may prosper from future production increases.
  • Researchpp 4441-4452He, Q., and Wang, X. (2015). "Drying stress relaxation of wood subjected to microwave radiation," BioRes. 10(3), 4441-4452.AbstractPDF
    An effective and rapid drying stress relieving technique was developed using microwave conditioning. The process was analyzed by measuring the stress factor and moisture content gradient through the thickness of the board. The experiments showed that the drying quality of E. urophylla x E. tereticornis was improved after microwave conditioning during the wood drying process. The drying stress relaxation increased with the duration of the microwave radiation. Stress and moisture content gradient through the thickness of the board were compared and are discussed in this report.
  • Researchpp 4453-4459Avula, S. V., Reddy, S., and Reddy, L. V. (2015). "The feasibility of mango (Mangifera indica L.) peel as an alternative substrate for butanol production," BioRes. 10(3), 4453-4459.AbstractPDF
    The suitability of dried mango peel as substrate for biobutanol production was investigated. The amount of mango waste generated can be very high; it has been recorded as high as 30% to 50% of the total weight of the fruit. The utilization of this waste is both a necessity and a challenge. Dried mango peel contains 30 ± 2.5% (w/w) of reducing sugars. Fermentation of mango peel extract by Clostridium acetobutylicum 2878 yielded 10.5 ± 0.4 g/L of butanol. The fermentation process was completed in seven days. Nutrients such as yeast extract, peptone, and beef extract were tested for supplementation of the mango peel medium. It was observed that nutrient supplementation improved both the rate and butanol production significantly, up to 13.3 ± 1.0 g/L of butanol. Scaling up studies using a bioreactor, with optimized mango peel extract medium and fermentation conditions, further improved the butanol production (15.42 ± 1.3 g/L). To the best of our knowledge, this is the first report on the utilization of mango peel for butanol production.
  • Researchpp 4460-4472Mo, C., Chen, N., Lv, T., Du, J., and Tian, S. (2015). "Direct ethanol production from steam-exploded corn stover using a synthetic diploid cellulase-displaying yeast consortium," BioRes. 10(3), 4460-4472.AbstractPDF
    The assembly of functional cellulolytic enzymes was displayed using a synthetic, cell-surface engineered diploid yeast consortium. Trichoderma reesei endoglucanase II (EGII), cellobiohydrolase II (CBHII), and Aspergillus aculeatus β-glucosidase I (BGLI) were displayed as fusion proteins with the AGA2p C-terminus of a-agglutinin on the cell surface of the diploid yeast strain Saccharomyces cerevisiae Y5. The cell-surface immobilization of each enzyme was confirmed by immunofluorescence microscopy. This type of yeast consortium allowed convenient optimization of ethanol production by adjusting the combination ratios of each cell type for inducing synergy in cellulose hydrolysis. Next, the direct ethanol fermentation from steam-exploded corn stover was investigated. The optimized cellulase-displaying consortium produced 20.4 g/L ethanol from 48.4 g cellulose per liter after 72 h in the presence of a small amount of cellulase reagent (0.9 FPU/mL). These results suggested the feasibility of the cellulase-displaying yeast consortium for simultaneous saccharification and fermentation from insoluble cellulosic materials.
  • Researchpp 4473-4484Wu, X., Xu, J., and Hao, J. (2015). "Calculating elastic constants of binderless bamboo-wood sandwich composite," BioRes. 10(3), 4473-4484.AbstractPDF
    Bending and shear stiffness, which are used as deformation resistance indexes, are very important mechanical properties of bamboo-wood sandwich composites. Thus, a new methodology to calculate the elastic constants of this type of material was proposed in this paper. First, the elastic constants of the composites were derived based on composite mechanics. In particular, the equivalent shear stiffness and modulus were determined by the energy method. Then, the three-point bending test and a revised three-point bending test were used to verify the accuracy of the theoretical model, which uses the properties of the skin and core layers as its input parameters. The model was subsequently evaluated. The results show that, generally, the predicted values were slightly smaller than the test results for the same bamboo-wood composite because of the strengthening of the wood veneer after hot-pressing.
  • Researchpp 4485-4497Wang, Z., Liu, S., Lin, W., and Song, W. (2015). "Influence of the zeolite ZSM-5 on catalytic pyrolysis of biomass via TG-FTIR," BioRes. 10(3), 4485-4497.AbstractPDF
    Bio-oil from the pyrolysis of biomass is an important renewable source for liquid fuel. However, the application of bio-oil has been severely restricted due to its high viscosity, acidity, and low heating value. Thus, it has been necessary to upgrade bio-oil for automobile fuel via catalytic deoxygenation reactions. Herein, the effects of the zeolite ZSM-5 on the pyrolysis of four biomass materials (corn cob, corn straw, pine powder, and cellulose) were investigated via TG-FTIR (thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer) to better understand the working mechanism of ZSM-5. The contents of the products of H2O, CO, CO2, and the C-O, C=O, and OH groups evolved with increasing pyrolytic temperature were monitored by FTIR. It was found that the relative contents of the C-O and C=O groups were decreased under the catalysis of ZSM-5, while the formations of CO, H2O, and the OH containing compounds were promoted. To explain the regulations, reaction routes were speculated and the catalytic conversion mechanisms were deduced.
  • Researchpp 4498-4518Sadaka, S., Liechty, H., Pelkki, M., and Blazier, M. (2015). "Pyrolysis and combustion kinetics of raw and carbonized cottonwood and switchgrass agroforests," BioRes. 10(3), 4498-4518.AbstractPDF
    Raw biomass is not commonly suitable as feedstock for existing power plants, mainly because of the substantial required infrastructural changes. As a result, most raw feedstock requires pre-treatment to improve its physical and thermal characteristics. Biomass carbonization is one of the pre-treatments that produces charcoal-like feedstock. This paper explores the effects of the carbonization process on the physiochemical characteristics of biomass produced from two cottonwood clones, S7C20 and ST66, and switchgrass (var. Alamo). Additionally, it studies the thermal degradation kinetics of raw and carbonized agroforestry products in nitrogen and air environments. Feedstock samples were carbonized in a batch reactor at 400 °C in an oxygen-free environment for 2 hours. Carbonization decreased biomass bulk density, moisture content, and volatile solids while increasing fixed carbon, ash content, pH, and heating values. The heating value of S7C20, ST66, and switchgrass increased by 58.6%, 60.3%, and 69.7%, respectively. Carbonization increased the activation energy values under the condition of pyrolysis and decreased these values under the condition of combustion. The carbonization process produced a charcoal-like feedstock that may be processed with coal or even replace it.
  • Researchpp 4519-4529Li, W., Zhang, Y., and Lao, B. (2015). "Preparation and properties of liquefied banana pseudo-stem based PVAc membrane," BioRes. 10(3), 4519-4529.AbstractPDF
    A series of novel membrane materials were prepared based on liquefied banana pseudo-stem (LBPS) blended with various proportions of polyvinyl acetate emulsion (PVAc). The mechanical properties, structure, thermal stability, and cross-sectional morphologies were investigated using a universal testing machine, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), respectively. The addition of LBPS to PVAc led to a structural change, and this change depended on the reaction temperature. The enhancement of elongation and the thermostability of membranes is attributed to an increase in C-O-C groups. Furthermore, the LBPS/PVAc membranes have a higher water resistance.
  • Researchpp 4530-4543Saba, N., Paridah, T. M., Abdan, K., and Ibrahim, N. A. (2015). "Preparation and characterization of fire retardant nano-filler from oil palm empty fruit bunch fibers," BioRes. 10(3), 4530-4543.AbstractPDF
    The possibilities of utilizing an abundantly available agricultural waste, oil palm empty fruit bunch (OPEFB) fibers, for the development of nano-filler was investigated. The aim was to develop fire retardant nano-fillers from OPEFB fiber through grinding, chemical treatment (bromine water and SnCl2), and cryogenic crushing, followed by a high energy ball milling process. The structural, morphological, and thermal properties of nano-fillers were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The analysis revealed that the particle size distribution was reduced from micro to nano size in the range of around 14 to 100 nm. Scanning electron microscopy (SEM) observations revealed that the nanoparticles of OPEFB had irregular shapes. The elemental composition of the OPEFB were investigated by elemental dispersive X- ray analysis (EDX), showing the presence of tin, carbon, oxygen, chlorine, and bromine elements both before and after ball milling. Further, thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated that the developed nanofillers exhibited enhanced thermal properties compared to the untreated fibers. Such results suggest that the developed nano-filler can be used for the fabrication of nanocomposites with improved fire retardancy.
  • Researchpp 4544-4556Reixach, R., Espinach, F. X., Arbat, G., Julián, F., Delgado-Aguilar, M., Puig, J., and Mutjé, P. (2015). "Tensile properties of polypropylene composites reinforced with mechanical, thermomechanical, and chemi-thermomechanical pulps from orange pruning," BioRes. 10(3), 4544-4556.AbstractPDF
    This paper explores the evolution in the tensile strength of orange pruning fiber-reinforced polypropylene composites. The exploitation of these pruning’s can effectively avoid incineration, with the consequence of CO2 emissions and fire risk, while extending the value chain of the agricultural industry. This biomass was subjected to three different treatments yielding mechanical, thermomechanical, and chemi-thermomechanical pulps. It was found that 20 to 50% of these pulps, together with a coupling agent, were used as polypropylene reinforcement. The evolution in the tensile strength and morphological properties of the fibers, and the effect of treatments on these properties were analyzed. A modified rule of mixtures (mROM) was used to analyze the micromechanical properties of the interface. In addition, the mechanical properties were weighted against the fiber treatment yields. Finally, factors to compute the net contribution of the fibers to the final strength of the composite materials were proposed.
  • Researchpp 4557-4568Rahman, M. R., Hamdan, S., Hasan, M., Baini, R., and Salleh, A. A. (2015). "Physical, mechanical, and thermal properties of wood flour reinforced maleic anhydride grafted unsaturated polyester (UP) biocomposites," BioRes. 10(3), 4557-4568.AbstractPDF
    Physical, mechanical, and thermal properties of wood flour reinforced ungrafted and maleic anhydride grafted unsaturated polyester biocomposites were investigated. Composites were prepared using a Resin Transfer Moulding technique by varying wood flour loading (10, 15, 20, and 25 wt%) for both ungrafted and maleic anhydride grafted unsaturated polyester. Fourier transform infrared (FTIR) spectroscopic and scanning electron microscopic (SEM) analysis was utilized to study physical properties. Tensile and flexural tests were conducted for mechanical characterization, while thermal properties were evaluated using thermogravimetric analysis (TGA). FTIR and SEM results confirmed the presence of grafting onto the unsaturated polyester. The flexural strength and modulus of the composites were increased up to 20% filler loading, after which those values decreased, whereas, the tensile strength and Young’s modulus values increased only up to 15% filler loading. Maleic anhydride grafted composites had better mechanical properties compared to ungrafted composites. According to TGA results, maleic anhydride grafted composites showed enhanced thermal stability at the final decomposition stage.
  • Researchpp 4569-4579Zhai, M., Zhang, Y., Ge, T., Dong, P., and Zhao, C. (2015). "Simulation of a gas-solid flow field in a two-stage rice husk high-temperature pyrolysis and gasification cyclone gasifier," BioRes. 10(3), 4569-4579.AbstractPDF
    A scheme for using a two-stage cyclone gasifier for high-temperature rice husk pyrolysis and gasification to reduce the tar content in biogas is presented in this study. The two-stage cyclone gasifier consisted of an upper cyclone high-temperature pyrolysis chamber and a lower steam spray gasifier. The staging pyrolysis and gasification process used in this study can increase the carbon conversion efficiency and reduce tar content by increasing the pyrolysis temperature. This process uses part of the produced gas for combustion in an external burner to generate high-temperature (1600 °C) anaerobic flue gas and to provide heat for pyrolysis and gasification. This study simulates the isothermal gas phase and the gas-solid flow field for the upper cyclone chamber, as well as the gas-solid flow field, with steam (heat transfer between the steam and the gas is considered), for the entire gasifier by varying the structural and operational parameters. The optimal parameters for the cyclone gasifier for good mixing and lengthy residence (2.3 to 4.8 s) of the rice husk particles were found to be inlet angles of 20° and 30° with inlet velocities between 40 and 80 m/s.
  • Researchpp 4580-4587Liu, Y., Zhang, C., Li, B., Li, H., and Zhan, H. (2015). "Extraction and determination of total and soluble oxalate in pulping and papermaking raw materials," BioRes. 10(3), 4580-4587.AbstractPDF
    Oxalate exists in plant tissue in the form of soluble and insoluble salts. Determination of the oxalate content in a raw material is important for controlling oxalate scaling during the pulping and papermaking processes. In this study, oxalate extraction and determination of the total and soluble oxalate contents in several pulping and papermaking raw materials were investigated. It was found that soluble oxalate can be extracted completely by distilled water at 70 °C within 180 min. Total oxalate can be extracted completely by 2-mol/L hydrochloric acid at 70 °C within 210 min.
  • Researchpp 4588-4598Brenes-Angulo, O., Bond, B., Kline, E., and Quesada-Pineda, H. (2015). "The impact of vacuum-drying on efficiency of hardwood products manufacturing," BioRes. 10(3), 4588-4598.AbstractPDF
    Many wood product manufacturers are trying to increase competitiveness by implementing continuous improvement programs such as lean manufacturing. However, the lumber drying process can significantly affect manufacturing time and inventory size, thus limiting how “lean” the entire process can become. The goal of this research was to determine how vacuum drying technology could support lean manufacturing concepts relative to conventional drying technology in hardwood manufacturing. Two flooring manufacturers with drying operations were modeled, and simulations were used to determine differences in cycle time and work-in-process inventory. The total cycle time of vacuum drying was 78% and 90% less than conventional drying. Work-in-process inventory was reduced by 57% and 52%. The reduction of work-in-process inventory in the drying process represents a potential cost savings of $7.3 million and $13.6 million per year for each manufacturer, respectively. The reduction in inventory carrying costs, faster drying rates, and reduced cycle time demonstrate that vacuum drying could significantly improve the competitiveness of hardwood flooring manufacturers.
  • Researchpp 4599-4612Semple, K. E., Zhang, P. K., and Smith, G. D. (2015). "Stranding moso and guadua bamboo. Part II. Strand surface roughness and classification," BioRes. 10(3), 4599-4612.AbstractPDF
    In this study OSB strands produced by a CAE 6/36 disk flaker from re-saturated moso and guadua bamboo tissue were classified by surface quality and compared with industrial aspen OSB strands. Strands were first classified into three groups based on surface appearance and texture. The topographic features that characterize the surface were then measured using a laser surface profiler to give two surface roughness indicators; average roughness (Ra) and average maximum roughness (Rz). Guadua strand surface quality was extremely poor compared to moso due to its very large, dense vascular bundles. Ra and Rz values for many bamboo strands, particularly guadua, exceeded the typical diameter of resin droplets dispensed during industrial OSB blending, meaning that excessive roughness could compromise bonding efficiency in bamboo OSB.
  • Researchpp 4613-4625Guo, S., Dong, X., Liu, K., Yu, H., and Zhu, C. (2015). "Chemical, energetic, and structural characteristics of hydrothermal carbonization solid products for lawn grass," BioRes. 10(3), 4613-4625.AbstractPDF
    Hydrothermal carbonization (HTC) of lawn grass was carried out at 200 °C and 240 °C for 30 to 180 min. The chemical, energetic, and structural characteristics of HTC solid residues were investigated. Results from HTC experiments indicate that solid mass yield of all solid residues was 31 to 50%. The hydrogen/carbon (H/C) and oxygen/carbon (O/C) atomic ratios of all solid residues were 1.17 to 1.64 and 0.45 to 0.65, respectively. The higher heating value (HHV) increased up to 20.54 MJ/kg with increasing HTC residence time at 240 °C for 180 min. Both XRD patterns and FTIR spectra show that differences occur with samples treated as compared to the raw material. Solid hydrochar exhibited higher ordered structure characteristics and was mainly derived from amorphous components degradation when the residence time was increased from 30 to 180 min at 200 °C, while hydrochar formed from cellulose components degradation with increased residence time at 240 °C. According to the results studied, it was found that prolonged residence time was favorable to the formation of hydrochar from lawn grass.
  • Researchpp 4626-4640Pintiaux, T., Laourine, F., Vacamedina, G., Rouilly, A., and Peydecastaing, J. (2015). "Hydrophobic cellulose-based materials obtained by uniaxial high pressure compression: In-situ esterification with fatty acids and fatty anhydrides," BioRes. 10(3), 4626-4640.AbstractPDF
    High-pressure molding at an elevated temperature was investigated as a potential technique for performing the esterification of octanoïc acid and octanoïc anhydride on cellulose and miscanthus. Emulsion, solvent exchange, and high-pressure homogenizer pretreatments were performed on the reactants in order to improve liquid-solid contacts. After pretreatment, cellulose or miscanthus and octanoïc acid or octanoïc anhydride were molded at 220 MPa and an elevated temperature. The mechanical properties of the resulting compressed materials were measured, and the material was then ground and washed; the water drop angle was measured, and IR analysis was performed, as well as an accurate measure of the degree of substitution. The esterification reaction was confirmed, the water properties of the grafted cellulose were modified, and the mechanical properties of the modified materials were altered. From this pioneering work, a better understanding of the effect of the molding process on the reaction and production of water-resistant compressed cellulose materials was developed.
  • Researchpp 4641-4651Chen, Q., Guo, X., Ji, F., Wang, J., Wang, J., and Cao, P. (2015). "Warping and surface checking analysis of engineered wood flooring for heating systems," BioRes. 10(3), 4641-4651.AbstractPDF
    The objective of this paper was to investigate the warping and surface checking of engineered wood flooring that was exposed to a heating system. The effects of decorative veneer type, wood structure, and wood shape on warping and surface checking were studied in a laboratory with a simulated heating system. Poplar/seven layer plywood engineered hardwood (structure C) or a 9 mm think poplar substrate layer wood was used, which contained the two veneer surface layers, structure A and structure B. For each structure, two shapes (mono-block or three splice) were tested, and a total of eight different veneer wood types were used. The highest degree of warping was seen in Eucalyptus or sapele veneer types. The degree of warping was the greatest for structure C with mono-block, followed by structure A with mono-block, structure C with three splice, and structure A with three splice. According to the surface checking tests for wood type, American ash, eucalyptus, maple, or birch exhibited the easiest wear, whereas, eastern black walnut exhibited the hardest wear. The surface checking tests revealed that the ranking from easiest to hardest wear was structure B, structure A, and structure C.
  • Researchpp 4652-4662Liu, H. M., Wang, F. Y., Li, H. Y., Wang, X. D., and Qin, G. Y. (2015). "Subcritical butane and propane extraction of oil from rice bran," BioRes. 10(3), 4652-4662.AbstractPDF
    Rice bran oil was extracted using hexane, as well as subcritical butane and propane. The quality of rice bran oils obtained using these three solvents was comparatively studied. The results showed that subcritical fluid extraction oil showed higher concentrations of health-conducive components (such as vitamin E, oryzanol, and phytosterol) compared with hexane-extracted oil. Extraction solvent had an important effect on the distribution of linoleic acid and oleic acid. The sterol compositions in rice bran oils were identified to be composed of ethyl iso-allocholate, campesterol, stigmasterol, sitosterols, and cyclolanosts. NMR data showed that butane-extracted oil had the highest triacylglycerols (TAGs) content and that subcritical propane-extracted oil had the highest wax content among the oils extracted with these three extraction solvents. The oils extracted by subcritical butane and propane showed higher oxidative stabilities. These results indicate that subcritical fluid extraction technology could be a useful method for producing high-quality rice bran oils and could become widely used in industrial applications.
  • Researchpp 4663-4673Zheng, Y., and Lv, W. (2015). "Rattan cane modified with polyethylene glycol melamine-urea-formaldehyde resin," BioRes. 10(3), 4663-4673.AbstractPDF
    To effectively improve the strength of Plectocomia pierreana rattan cane without reducing its toughness, the cane was impregnated with a new water-soluble melamine-urea-formaldehyde (MUF) resin modified with low-molecular-weight polyethylene glycol (PEG), marked as PMUF. The PMUF synthetic process was optimized using an orthogonal test L9(34). Results showed that the dimensional stability, density, and most mechanical properties of modified canes were improved greatly. Compared with MUF, PMUF imparted the cane with higher anti-swelling efficiency (ASE), modulus of elasticity (MOE), modulus of rupture (MOR), and impact toughness. These improvements indicated that PMUF could effectively improve the cane’s dimensional stability and strength, while simultaneously retaining its flexibility. Based on a comprehensive evaluation, the optimum modification conditions were : PEG-400, PEG/Melamine mole ratio of 0.1, step-wise synthesis, and PMUF solution of 30%. The ASE of optimal modified canes reached 65.51%, and its mechanical properties such as the MOE, MOR, compressive modulus, and compressive strength increased by 135.61%, 129.01%, 106.22%, and 88.52%, respectively. Additionally, its impact toughness was only reduced by 6.85%. The PMUF modified P. pierreana canes is comparable to the commercial Daemonorops margaritae canes.
  • Researchpp 4674-4685Šedivka, P., Bomba, J., Böhm, M., and Zeidler, A. (2015). "Determination of strength characteristics of construction timber strengthened with carbon and glass fibre composite using a destructive method," BioRes. 10(3), 4674-4685.AbstractPDF
    Beams strengthened with a composite material consisting of carbon and glass fibre stabilised with two types of adhesives were evaluated. The primary objective was to determine the technical attributes of joints, the maximum bending strength capacity, deflection, and modulus of elasticity. The reinforcement fibres tested were based on carbon and glass fibre. Epoxy and polyurethane adhesives were used for stabilising the fibres on a spruce timber beam. Composite beams glued in both a prestressed and non-prestressed condition were tested and then compared with non-reinforced control beams. A four-point deflection pursuant to EN 408 (1995) was used in the determination of the strength of the load-bearing construction beams based on composites, consisting of a fibre type, adhesive type, and spruce timber. This approach was applied to define the size of the construction beams and process the measurement results. Reinforcing construction beams with fibres applied in a prestressed condition resulted in an increase in the bending strength capacity by 31.6 to 44.4% compared with a non-reinforced solid timber construction beam. These construction elements, strengthened with carbon and glass fibre composites glued with epoxy and polyurethane adhesives, are suitable for applications that require bending resistance perpendiculary to the glued joint direction.
  • Researchpp 4686-4693Sözbir, G. D., Bektaş, I., and Zülkadir, A. (2015). "Lignocellulosic wastes used for the cultivation of Pleurotus ostreatus mushrooms: Effects on productivity," BioRes. 10(3), 4686-4693.AbstractPDF
    The potential for using cotton seed hulls (CSHs) and walnut shells (WSs) as new, essential substances for substrate preparation in the cultivation of Pleurotus ostreatus was studied. Substrates prepared with oak sawdust alone (OS) and with mixtures of OS and CSHs and WSs in different ratios were compared, and their effects on the earliness, total time, yield, and biological efficiency (BE) were determined. The nitrogen (N) content of the substrates prepared using CSHs and WSs alone was high, so the C:N ratio of the substrates diminished as the proportions of CSHs and WSs in the mixtures were increased. The highest yields were obtained from substrates containing the maximum amount of N. The highest yield and highest biological efficiency were obtained for a mixture of 25OS:75CSHs, indicating that the yield in the substrates increased as the amount of CSHs in the mixtures increased. The morphological characteristics were influenced by the various substrates and their various ratios. The properties of mushroom cultivation in bags were related to the nitrogen content, as indicated by the C:N ratios. The results indicated that CSHs and WSs could be used as new, essential substances in the preparation of substrates for the cultivation of Pleurotus ostreatus.
  • Researchpp 4694-4710Xu, X., Liu, M., and Dai. X. (2015). "Expression of recombinant Bacillus amyloliquefaciens xylanase A in Escherichia coli and potential application in xylan hydrolysis," BioRes. 10(3), 4694-4710.AbstractPDF
    Bacillus amyloliquefaciens xylanase A (baxA), an endoxylanase (EC. gene, was cloned through PCR using the genome of B. amyloliquefaciens as a template. The open reading frame of baxA was 642 bp, and the gene encoded a 213 amino acid protein with a predicted molecular mass of 23.3 kDa. reBaxA1 produced in Escherichia coli with the pET30a(+) vector (T7 lac promoter) formed inclusion body and did not show any xylanase activity. reBaxA2 produced in E. coli with the pCold TF vector (cspA lac promoter) showed high xylanase activity; this enzyme was secreted into the culture medium and remained in the cell. Sodium dodecyl sulphate–polyacrylamide gel electrophoresis analysis showed that the molecular weights of reBaxA1 and reBaxA2 were approximately 28.5 and 77.2 kDa, respectively. The optimal activity of reBaxA2 occurred at 55 °C and pH 6.0. Moreover, the Michaelis–Menten constant (Km) and maximal activity (Vmax) of reBaxA2 were 4.98 mg•ml-1 and 12.79 μmol•min–1•mL–1, respectively. High–performance liquid chromatography analysis showed that reBaxA2 released xylooligosaccharides from birchwood, beechwood, and oat spelt xylans, with xylopentaose, xylotriose, and xylotetraose as major products, respectively.
  • Researchpp 4711-4725Pulkrab, K., Sloup, R., and Podrázský, V. (2015). "Production potential of the forests in the Czech Republic," BioRes. 10(3), 4711-4725.AbstractPDF
    This article discusses the production potential (and limits) of the forests in the Czech Republic (CR). The calculation respects ecological limits set by typological system and the Czech forestry legislation. The key criterion of the production evaluation is the total mean increment. Usually, a forest owner can choose amongst several variants of management. The analysis in this work examines the two limit variants – the minimum and maximum production potential. The results show that, e.g., the Norway spruce share might be 19 to 48% of the total area of Czech forests (51.4% at present). The target management the owners opt for (Norway spruce, pine, oak, and beech) can, in the future, influence the timber processing industry, the main purchaser of timber raw material from Czech forests. The maximum variant shows 9,134 thousand m3 of available coniferous round timber, while the minimum one only 3,802 thousand m3 per year. Therefore, the timber processing industry should keep a close watch on the situation and either try to persuade forest owners to choose the alternative of the target management that would provide sufficient assortment for timber processing, or adjust the manufacture to the possible changes in the species composition of the forests.
  • Researchpp 4726-4739Lunguleasa, A., Spirchez, C., and Griu, T. (2015). "Effects and modeling of sawdust torrefaction for beech pellets," BioRes. 10(3), 4726-4739.AbstractPDF
    This study was done to determine the effects of beech sawdust torrefaction on pellets obtained in the laboratory. Torrefied beech (Fagus sylvatica L.) sawdust was used to make pellets. This species was chosen based on the existence of a market for such micro-briquettes. Rigorous comparisons between torrefied and non-torrefied pellets were conducted. It was found that treating the sawdust had both beneficial and non-beneficial effects, but the total effect is positive. Economical elements were also considered, emphasizing the use of wood biomass as fuel. Theoretical and experimental aspects are taken into consideration, the experimental results being used to validate the theoretical model. The experiments performed demonstrate that heat treatment can add value if it meets certain parameters, such as a maximum temperature of 260 °C for 5 min. Heat treatment of beech sawdust in the form of pellets or briquettes was shown to be a simple, viable, effective treatment because the heating process improves the calorific value and other relevant properties of the torrefied sawdust.
  • Researchpp 4740-4750Bučar, D. G., and Merhar, M. (2015). "Impact and dynamic bending strength determination of Norway spruce by impact pendulum deceleration," BioRes. 10(3), 4740-4750.AbstractPDF
    This research was conducted to determine the impact bending strength and dynamic bending strength of Norway spruce wood from Slovenia. An accelerometer was added to the impact pendulum in order to capture the material’s response to an instantaneous load. Impact bending strength of specimens were determined by standard method measuring the height of pendulum before and after the break. While measuring the impact pendulum decelerations during the fracture of the specimen, the impact bending strength and dynamic bending strength was calculated. Correlations between the measured properties were determined, for which the R2 was in the range 0.88 to 0.51 between the standard and accelerometer method and between the impact bending strength and dynamic bending strength, respectively. The results confirmed that the methods used to determine the impact bending strength were comparable and that it was possible to determine dynamic bending strength on the basis of impact pendulum deceleration measurement.
  • Researchpp 4751-4767Segovia, F., Blanchet, P., Barbuta, C., and Beauregard, R. (2015). "Aluminum-laminated panels: Physical and mechanical properties," BioRes. 10(3), 4751-4767.AbstractPDF
    Aluminum lamination was performed to improve the physical and mechanical properties of several wood-based composite panels. The panels were aluminum-laminated on two faces in a hot press at 689 kPa and 120 °C for 6 min. Four types of wood-based composites were used as cores, and aluminum 3003 alloy sheets were used for face laminations. Polyurethane adhesive ensured bonding strength between the wood-based composite and the aluminum sheets. The objective was to assess sandwich composite panels made of wood-based composites as a core layer with aluminum-laminated faces. This study evaluated the physical and mechanical properties of these panels. The results show that aluminum-laminated panels had higher dimensional stability (thickness swelling and linear expansion values). Bending properties such as the apparent modulus of elasticity (Eapp) and the modulus of rupture (MOR) were significantly increased with face-lamination. Medium-density fiberboard (MDF) laminate presented an increase of 554% for Eapp and 570% for MOR in comparison with non-laminated MDF panels. The shear edgewise strength for oriented strand board and plywood increased by 44% and 77%, respectively. The results confirm that aluminum-laminated panels have the potential to be used as structural panels in future applications.
  • Researchpp 4768-4783Hossein, M. A., Talaeipour, M., Hemmasi, A. H., Bazyar, B., and Mahdavi, S. (2015). "Effects of sequencing enzyme application and refining on DIP properties produced from mixed office waste paper," BioRes. 10(3), 4768-4783.AbstractPDF
    The effect of changing the sequence of refining and enzymatic treatment on the properties of deinked pulp from mixed office waste paper (MOW) was investigated. The sequences included refining before and after enzymatic treatment. Refining was applied for 700 and 1500 revolutions, and the consistency of pulps during enzymatic treatment was 5, 8, and 13%. Enzymatic treatment was applied for 20, 40, and 60 min. After each of the sequences, the deinking stage was the same. When refining was applied after the enzymatic treatment, the freeness of pulp was greater than that of the pulp on which refining was conducted before the enzymatic treatment, at a constant refining speed. Better strength properties were produced when refining was carried out before the enzymatic treatment. Also, the results of testing the optical properties of deinked pulp showed that brightness and ERIC improved when refining was carried out before the enzymatic treatment.
  • Researchpp 4784-4794Liu, G., Zhang, G., Wang, P., Xiang, R., and Fu, X. L. (2015). "Synthesis and application of polymeric fluorescent compounds based on coumarin," BioRes. 10(3), 4784-4794.AbstractPDF
    In this work, a multifunctional yellowing inhibitor was synthesized by the Pechmann method. In order to obtain the target compound, 7-hydroxy-4-methyl coumarin was prepared by using the raw materials of resorcinol and ethyl acetoacetate, with toluene-p-sulfonic acid as the catalyst. New polymeric fluorescent compounds were synthesized by connecting the 7-hydroxy-4-methyl coumarin, the hindered amine light stabilizer 4-amion-2,2,6,6-tetramentylniperidine, and a series of polyethylene glycol segments into the same molecule with cyanuric chloride as a bridge. The structures of the synthesized molecules were confirmed by FT-IR, 1H NMR, and elemental analysis. The luminescent properties of the fluorescent compounds were studied by UV-vis spectroscopy and fluorescence spectroscopy. The integration effect between the fluorescent compounds and paper was tested by a scanning electron microscope. The light stability effect on the paper sheet was tested using an ultraviolet aging apparatus. The results indicate that the polymeric fluorescent compounds had a positive effect on the light stability of the high-yield pulp.
  • Researchpp 4795-4810Ang, A., Ashaari, Z., Bakar, E. S., and Ibrahim, N. A. (2015). "Characterization and optimization of the glyoxalation of a methanol-fractionated alkali lignin using response surface methodology," BioRes. 10(3), 4795-4810.AbstractPDF
    The glyoxalation of a methanol-fractionated alkali lignin was executed at 60 °C for 8 h with different amounts of glyoxal (40% in water) and 30% NaOH. The weights of the lignin and water were fixed at 10.0 and 15.0 g, respectively. The gel permeation chromatography (GPC) results indicated that depolymerization of lignin molecules occurred during the glyoxalation process. However, a higher polydispersity index (Mw/Mn) of all glyoxalated lignins compared to the unmodified lignin (ML) showed that lignin polymers with a variety of chain lengths were generated through the crosslinking and through the repolymerization of lignin molecules via methylene (CH2) bridges and new, strong C-C bonds after the condensation reaction. This was confirmed by thermogravimetry analysis (TGA). Optimum amounts of glyoxal and NaOH to be used in the glyoxalation process were ascertained by quantifying the intensity of relative absorbance for the CH2 bands obtained from FT-IR spectra and by using response surface methodology (RSM) and central composite design (CCD), which facilitated the development of a lignin with appropriate reactivity for wood adhesive formulation. The experimental values were in good agreement with the predicted ones, and the model was highly significant, with a coefficient of determination of 0.9164. The intensity of the relative absorbance for the CH2 band of 0.42 was obtained when the optimum amounts of glyoxal and NaOH, i.e., 0.222 and 0.353, respectively, were used in the glyoxalation process.
  • Researchpp 4811-4825Zhai, R., Song, B., and Zhou, X. (2015). "Modifying the refining energy consumption of chemi-mechanical pulping with NaOH-thiourea-urea aqueous solution," BioRes. 10(3), 4811-4825.AbstractPDF
    To reduce the refining energy consumption of chemi-mechanical pulping, treatment with NaOH-thiourea-urea aqueous solution was studied in this work. By means of single-factor experiments, the effects of alkali dosage, soaking time, and freezing time were evaluated. It was found that the optimal conditions were an alkali dosage of 8%, soaking time of 45 min, and freezing time of 105 min. The results revealed that refining energy consumption could be reduced by approximately 40% under optimal conditions compared with that of alkaline peroxide mechanical pulp, while other pulping or paper-making properties were similar. There were no significant effects on the structure of the functional groups, the crystalline region of the pulp, or the whole structure of the treated wood chips. However, damage to single wood fibers on the chips treated in NaOH-thiourea-urea aqueous solution was more obvious.
  • Researchpp 4826-4842Huang, R., Mei, Z., Long, Y., Xiong, X., Wang, J., Guo, T., Luo, T., and Long, E. (2015). "Impact of optimized flow pattern on pollutant removal and biogas production rate using wastewater anaerobic fermentation," BioRes. 10(3), 4826-4842.AbstractPDF
    This paper introduces a new-type of antigravity mixing method, which was applied in the biogas production process, using organic wastewater fermentation. It was found that the digesters with two designs, a high-position, centralized pressure outlet and a high-position, dispersed pressure outlets, both lead to an increase in biogas production rates by 89% and 125%, respectively. The biogas production peak appeared 1 day and 7 days earlier, and the COD removal rates were raised by 27% and 42%, respectively. The results indicated that the optimized flow field had a significant impact. This work also explains the mechanism of flow field optimization using computational fluid dynamics (CFD) software for the simulation of the flow field form in the hydraulic mixing.
  • Researchpp 4843-4853Ni, J., Wen, Y., and Liu, H. (2015). "Preparation of micro-crystalline cellulose-reinforced polyacrylic acid hydrogel and its application in paper/polyacrylic acid composites," BioRes. 10(3), 4843-4853.AbstractPDF
    Paper/polyacrylic acid (PAA) composites were prepared using a micro-crystalline cellulose (MCC)-reinforced PAA hydrogel. The MCC-reinforced PAA hydrogel was prepared by in-situ UV light-induced polymerization of acrylic acid in the presence of MCC. The experimental results showed that the presence of MCC improved the water absorption capacity of the resulting PAA hydrogel. The addition of 1 wt% MCC (based on the dry weight of acrylic acid) in the hydrogel matrix resulted in an increase in the water absorption capacity of the PAA hydrogel by 122 g water/g hydrogel (i.e., from 427 to 549 g/g). Paper/PAA composites were then made by surface loading of the MCC-reinforced PAA hydrogel fine particles. Using 2 g of MCC-reinforced PAA hydrogel particles per square meter of paper, the water absorbance of the paper/PAA composites reached 1096 g/m2. Potential applications of these paper/PAA composites are also discussed in this work.
  • Researchpp 4854-4866Zheng, X., Chang, J., and Fu, Y. (2015). "Catalytic hydrotreatment of light distillates obtained from bio-oil for use in oxygenated liquid fuels," BioRes. 10(3), 4854-4866.AbstractPDF
    Bio-oil can be fractionated into three parts according to their boiling points. This research reported that light distillates could be converted into oxygenated liquid fuels through a two-stage hydrotreatment approach, using a Pd/C catalyst. The main goal of the first hydrotreatment stage was to stabilize the high active components, which contained carbon–carbon double bonds and aldehyde groups. The second hydrotreatment stage aimed to saturate the components with benzene rings and keto groups, resulting in saturated oxygenated compounds. The H/Ceff ratio was improved greatly after the two-stage hydrotreatment, increasing from 0.51 (in the reactant) to 1.67 (in the final products). The high heating value of the final products was 31.63 MJ/kg. After the two-stage hydrotreatment, the main products were C5–C9 alcohols, which were tested via gas chromatography–mass spectrometry. The products could be blended with gasoline directly. Based on the experiments regarding the hydrogenated model compounds, a reaction schematic for the two-stage hydrotreatment was created. Moreover, the bio-oil hydrotreatment kinetics were investigated. The order of the hydrotreatment reaction was 2.0, and the apparent activation energy (Ea) was 57.29 KJ/mol.
  • Researchpp 4867-4876Roohnia, M., and Kohantorabi, M. (2015). "Dynamic methods to evaluate the shear modulus of wood," BioRes. 10(3), 4867-4876.AbstractPDF
    There are different dynamic or static test methodologies for evaluating the shear and torsional moduli of wood. A preferred method is nondestructive, accurate, and standard. However, dynamic methods using conventional devices previously suggested for determining the orthotropic shear moduli of wood are neither accurate nor standard. Thus, a reliable method for evaluating the torsional modulus of wood through a torsional vibration test exists; however, it is not a standard test method at all. In this study, a standard methodology for refractory materials, ASTM C1548, was fitted to wood to meet the qualifications suggested in measuring the torsional vibration of an orthotropic material. A methodology based on Timoshenko’s advanced theory of free flexural vibration for orthotropic shear moduli was also defined to be compared to these reliable, standard procedures of torsional modulus evaluation. A promising conclusion was derived using improved computer-based instrumentation.
  • Researchpp 4877-4885Li, H., Qian, X., Li, T., and Ni, Y. (2015). "Percolation for coated conductive paper: Electrical conductivity as a function of volume fraction of graphite and carbon black," BioRes. 10(3), 4877-4885.AbstractPDF
    Conductive papers were prepared via surface coating with graphite or carbon black using either carboxylated styrene butadiene latex or starch as the binder. It is of practical interest to determine the percolation threshold for the coated paper product made using a binary system consisting of conductive filler and binder. In this study, the electro-conductivity threshold of various conductive papers was determined based on experimental data according to the percolation law. Results showed that the conductivity of coated, conductive paper is a function of the volume fraction of conductive filler, which can be described well by the percolation theory. The percolation thresholds of graphite/latex, graphite/starch, carbon black/latex, and carbon black/starch coatings were 17.66, 12.36, 11.71, and 8.69 vol.%, respectively. At concentrations higher than the percolation threshold, the conductivity of conductive paper using graphite as the conductive filler was much higher than that achieved using carbon black at a similar volume fraction. The present paper has significant practical implications for conductive paper technology using graphite filler based on surface coating technology.
  • Researchpp 4886-4902Shahriarinour, M., and Ramanan, R. N. (2015). "Purification and characterisation of extracellular cellulase main components from Aspergillus terreus," BioRes. 10(3), 4886-4902.AbstractPDF
    The filamentous fungus Aspergillus terreus was cultivated in a 2-L stirred tank bioreactor, and the resulting culture filtrate was used for protein purification. From the cultivation broth, seven crude extracts of glucanase and one of β-glucosidase were purified. A total of eight components were identified, including endoglucanases (Endo I, II, III, and IV), cellobiohydrolases (CBH I, II, and III), and β-glucosidase. The eight major components in the fermentation broth of A. terreus, which most likely constitute the essential enzymes for cellulose hydrolysis, were further purified by a series of column chromatography steps. Interestingly, the β-glucosidase from A. terreus displayed an extremely high activity on p-nitrophenyl-β-D-glucopyranoside (pNPG), which suggests that it is a good candidate enzyme for the conversion of cellobiose to glucose. The temperature and pH ranges for optimal activity of the purified enzyme were 46 to 62 °C and 5.0 to 6.0, respectively.
  • Researchpp 4903-4912Xu, K., Chen, T., Zheng, Z., Huang, S., Li, K., and Zhong, T. (2015). "Effects of natural chitosan as biopolymer coupling agent on the pyrolysis kinetics of wood flour/polyvinyl chloride composites," BioRes. 10(3), 4903-4912.AbstractPDF
    The thermal degradation behavior and pyrolysis kinetic models of wood flour (WF)/PVC composites before and after adding chitosan were studied using thermogravimetry (TGA) and nine common kinetic model functions (f(α)). The results indicated that the thermal degradation temperature of WF/PVC composites was delayed to a higher value after adding chitosan. The first-order reaction order (L1) model and second-order reaction order (L2) model were found to be the best reaction order functions for the description of mass loss kinetics of WF/PVC without chitosan during the first and second stages. Two L2 models were suitable for both degradation stages of WF/CS/PVC. Activation energy (E) and frequency factor (A) for WF/PVC and WF/CS/PVC corresponded to 26.05 kJ·mol-1, 4.08×103 s-1, and 40.89 kJ·mol-1, 2.11×1010 s-1 at the first degradation stage, respectively, and 97.83 kJ·mol-1, 1.11×107 s-1 and 92.88 kJ·mol-1, 1.56×1011 s-1 at the second degradation stage.
  • Researchpp 4913-4921He, M., and Di, M. (2015). "Using non-destructive testing to determine the correlation between dynamic mechanical properties and bonding strength of wood-plastic composite adhesive joints," BioRes. 10(3), 4913-4921.AbstractPDF
    Wood-plastic composites (WPC) have been developed into new and important wood-based composites because of their benefits for the environment, economy, and recyclability. When combined with structural adhesives, WPCs will have a greatly broadened application in the construction field. In this work, epoxy resin and acrylic ester were used to bond WPC adhesive joints. The shear strength of the adhesive joints was determined and investigated. Resonant frequency and dynamic modulus of elasticity (MOE) of the WPC adhesive joints were measured using the longitudinal vibration method. The correlation between different vibration parameters and shear strength of WPC adhesive joints was also investigated. Results showed that the epoxy resin had a better bonding quality than the acrylic ester on the bonding of WPC adhesive joints. The resonant frequency, dynamic MOE, and the dynamic MOE ratio of the WPC adhesive joints had close correlations with their shear strength for the samples bonded with epoxy resin.
  • Researchpp 4922-4932Li, B., Zhang, C., Fu, S., and Liu, Y. (2015). "Stabilization of potentially sticky substances in pulp mill process water with polysaccharides," BioRes. 10(3), 4922-4932.AbstractPDF
    Characterization of the dissolved and colloidal substances (DCS) in the process water of a bleached chemithermomechanical pulp (BCTMP) production line showed that the major lipophilic substances (wood resins) were dehydroabietic acid, linoleic acid, oleic acid, and palmitic acid. Model compound experiments indicated that polysaccharides contained in DCS had significant effects on the stability of the system. Effects of neutral and acidic polysaccharides on the stability of wood resins (model resin acid R and fatty acid O) in the presence of metal ions were then investigated. No calcium-induced aggregation occurred when the concentration ratio of added neutral polysaccharide to R and O exceeded 0.2 and 1.0, respectively. Acidic polysaccharide could further degrade the stability of resin dispersions in the presence of calcium ions and yet have a positive effect in the presence of only sodium ions.
  • Researchpp 4933-4946Diop, A., Jradi, K., Daneault, C., and Montplaisir, D. (2015). "Kraft lignin depolymerization in an ionic liquid without a catalyst," BioRes. 10(3), 4933-4946.AbstractPDF
    In this paper, the depolymerization of lignin was successfully achieved by the thermal treatment of kraft lignin in butyl-1,8-diazabicyclo[5.4.0]undec-7-enium chloride ([DBUC4+][Cl-]) without a catalyst. The thermal treatment experiments were performed in an oven at 150, 200, and 250 °C for 1 h. The changes in kraft lignin structure over the course of depolymerization were characterized by gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, and 1H / 31P NMR analyses. GPC chromatograms indicated that the retention time of the original kraft lignin had shifted toward higher values after the thermal treatment, which indicated lignin depolymerization. The average molecular weight of the lignin obtained after 1 h reaction time decreased by 23, 70, and 58 wt% for the treatment at 150, 200, and 250 °C, respectively. FTIR spectra indicated the cleavage of β-O-4 bonds of kraft lignin. The 1H NMR spectra showed demethylation of all treated kraft lignins. Moreover, the 31P NMR analysis demonstrated that the demethylation phenomenon of the treated kraft lignin contributed to the formation of catechol groups.
  • Researchpp 4947-4960Dahlen, J., Antony, F., Li, A., Love-Myers, K., Schimleck, L., and Schilling, E. B. (2015). "Time-domain reflectometry for the prediction of loblolly pine and sweetgum moisture content," BioRes. 10(3), 4947-4960.AbstractPDF
    Time-domain reflectometry (TDR) can be used to predict the moisture content in porous materials, including soil, and is an exciting tool that could be used to measure the moisture content in wet-stored wood. Three-rod probes with 127 mm- or 152 mm-long rods were inserted into 62 loblolly pine and 34 sweetgum saturated bolts. The bolts were air dried over a span of five weeks. TDR waveforms and moisture content were periodically recorded. In total, 534 and 482 readings were taken for the loblolly pine and sweetgum bolts, respectively. An algorithm in R was written to automatically analyze the apparent length of the TDR rods. Calibration models were developed between moisture content and X (apparent length / actual rod length). A three-parameter logistic model was developed for loblolly pine (R2=0.64) and sweetgum (R2=0.84). The process was repeated using shorter bolts and 152 mm-long rods, resulting in improved models for loblolly pine (R2=0.99) and sweetgum (R2=0.97). Overall, TDR and the algorithm written to analyze the waveforms were accurate in predicting moisture content and could be used to monitor moisture in wet-decks.
  • Researchpp 4961-4969Yamada, T., Yamaguchi, M., Kubo, S., and Hishikawa, Y. (2015). "Direct production of alkyl levulinates from cellulosic biomass by a single-step acidic solvolysis system at ambient atmospheric pressure," BioRes. 10(3), 4961-4969.AbstractPDF
    A simple method was invented to achieve a high yield of cellulosic biomass-derived alkyl levulinates, which have the potential to be alternative fuel additives. Alkyl levulinates, such as butyl-, pentyl-, and hexyl levulinates, were produced using single-step acid-catalyzed solvolysis of cellulosic biomass without the use of elevated pressure. Reactions were performed by refluxing alcohols such as 1-butanol, 1-pentanol, and 1-hexanol at their boiling points of 117, 138, and 157 °C, respectively, with sulfuric acid at ambient pressure. After 1 hour of the reaction, the cellulosic biomass was converted into an alcohol-soluble compound, and a high yield of alkyl levulinates was achieved. Although the process involved simple treatment under atmospheric pressure, the alkyl levulinate yield was quite high: 60 to 80% based on the hexose content of the cellulosic biomass. The factors influencing the reaction, such as the accessibility to cellulose and acidity of the reaction media, could be controlled appropriately in this solvolysis system.
  • Researchpp 4970-4977Wu, C., Zhou, S., Li, R., Wang, D., and Zhao, C. (2015). "Reactivity improvement of bamboo dissolving pulp by xylanase modification," BioRes. 10(3), 4970-4977.AbstractPDF
    A high reactivity is an essential prerequisite for dissolving pulp. In this study, xylanase modification to increase the reactivity of bamboo dissolving pulp was investigated. The original reactivity of a bamboo dissolving pulp prepared by a prehydrolysis kraft pulping process and bleached by (OP)-H-P (oxygen delignification enhanced with peroxide - sodium hypochlorite - peroxide) is very low. The reactivity of the pulp was increased drastically after xylanase modification, which lowered the pulp’s pentosan content. Simultaneously, the crystallinity index of the dissolving pulp decreased slightly after xylanase modification. The microscopic appearance of the fiber surfaces changed slightly. The average curl and kink indices were lower at a xylanase charge of 1.0 IU/g compared to the other charges, while changes to the yield loss and the degree of polymerization were negligible. The mechanism for the increased pulp reactivity is discussed.
  • Researchpp 4978-4996Bailleres, H., Denaud, L., Butaud, J.-C., and McGavin, R. L. (2015). "Experimental investigation on rotary peeling parameters of high density coconut wood," BioRes. 10(3), 4978-4996.AbstractPDF
    Substantial quantities of senile coconut palms are present in plantations within the Asia-Pacific region. Once coconut palms become over-mature, their production of traditional products, such as coconuts, significantly decreases, resulting in profitability challenges for farmers. Presently, few profitable markets exist for over-mature, senile coconut palms. Using the coconut palm stem in composite or engineered wood products could, however, provide an attractive alternative. Due to some of its unique characteristics, a processing system able to recover wood from the high-density zone near the stem periphery is desirable. A series of rotary veneer laboratory trials were undertaken to establish fundamental benchmark lathe settings and veneering characteristics for coconut palm stems. Different pressure bar configurations, billet pre-treatment temperatures, and veneer thicknesses were tested, and the resulting cutting forces and veneer quality were assessed. Optimal setting recommendations for peeling coconut wood are provided.
  • Researchpp 4997-5015Sandquist, D., Norell, L., and Daniel, G. (2015). "Quantitative evaluation of hybrid aspen xylem and immunolabeling patterns using image analysis and multivariate statistics," BioRes. 10(3), 4997-5015.AbstractPDF
    A new method is presented for quantitative evaluation of hybrid aspen genotype xylem morphology and immunolabeling micro-distribution. This method can be used as an aid in assessing differences in genotypes from classic tree breeding studies, as well as genetically engineered plants. The method is based on image analysis, multivariate statistical evaluation of light, and immunofluorescence microscopy images of wood xylem cross sections. The selected immunolabeling antibodies targeted five different epitopes present in aspen xylem cell walls. Twelve down-regulated hybrid aspen genotypes were included in the method development. The 12 knock-down genotypes were selected based on pre-screening by pyrolysis-IR of global chemical content. The multivariate statistical evaluations successfully identified comparative trends for modifications in the down-regulated genotypes compared to the unmodified control, even when no definitive conclusions could be drawn from individual studied variables alone. Of the 12 genotypes analyzed, three genotypes showed significant trends for modifications in both morphology and immunolabeling. Six genotypes showed significant trends for modifications in either morphology or immunocoverage. The remaining three genotypes did not show any significant trends for modification.
  • Researchpp 5016-5029Sandquist, D., Norell, L., Takabe, K., Yoshinaga, A., and Daniel, G. (2015). "Anatomical and immunocoverage observations on SuSy, C4H, and pectate lyase family protein down-regulated aspens genotypes," BioRes. 10(3), 5016-5029.AbstractPDF
    This study aims to complement previous studies on down-regulation of sucrose synthase and cinnamate 4-hydroxylase in hybrid aspen (Bjurhager et al. 2010; Gerber et al. 2014) with a quantitative anatomical comparison (Sandquist et al. 2015). The main focus was placed on evaluating quantitative modifications to fiber morphology and lignin composition. This was achieved by combining results from light-, electron-, and UV-microscopy together with histochemical staining. Overall there was good agreement between the morphological results in this study compared to the previously published chemical and physical reports, particularly on cinnamate 4-hydroxylase down-regulated aspen. The previously reported statistical correlations between fiber lumen area and plant diameter, and fiber length and tree height (Sandquist et al. 2015) have been further refined. Knock-down of genes coding for biologically important proteins such as sucrose synthase and cinnamate 4-hydroxylase had broad spanning morphological impacts. Down-regulated sucrose synthase genotype showed significantly reduced fiber development, possibly with altered S/G ratio. Down-regulated cinnamate 4-hydroxylase genotype showed an overall reduction of lignin in fibers as indicated from both chemical staining and UV-microscopy measurements. Down-regulated pectate lyase genotype showed no overall significant effects on fiber morphology, ultrastructural, nor lignin staining.
  • Researchpp 5030-5048Hindi, S. S. Z., and Abohassan, R. A. (2015). "Cellulose triacetate synthesis from cellulosic wastes by heterogeneous reactions," BioRes. 10(3), 5030-5048.AbstractPDF
    Cellulosic fibers from cotton fibers (CF), recycled writing papers (RWP), recycled newspapers (RN), and macerated woody fibers of Leucaena leucocephala (MWFL) were acetylated by heterogeneous reactions with glacial acetic acid, concentrated H2SO4, and acetic anhydride. The resultant cellulose triacetate (CTA) was characterized for yield and solubility as well as by using 1H-NMR spectroscopy and SEM. The acetylated product (AP) yields for CF, RWP, RN, and MWFL were 112, 94, 84, and 73%, respectively. After isolation of pure CTA from the AP, the CTA yields were 87, 80, 68, and 54%. The solubility test for the CTA’s showed a clear solubility in chloroform, as well as mixture of chloroform and methanol (9:1v/v) and vice versa for acetone. The degree of substitution (DS) values for the CTA’s produced were nearly identical and confirmed the presence of CTA. In addition, the pore diameter of the CTA skeleton ranged from 0.072 to 0.239 µm for RWP and RN, and within the dimension scale of the CTA pinholes confirm the synthesis of CTA. Accordingly, pouring of the AP liquor at 25 °C in distilled water at the end of the acetylation and filtration did not hydrolyze the CTA to cellulose diacetate.
  • Researchpp 5049-5070Song, W., Zhao, F., Yu, X., Wang, C., Wei, W., and Zhang, S. (2015). "Interfacial characterization and optimal preparation of novel bamboo plastic composite engineering materials," BioRes. 10(3), 5049-5070.AbstractPDF
    To blaze new trails for utilizing forestry processing residue, higher plant content biocomposites were proposed based on a combination of moso bamboo flour/silane KH550/high density polyethylene (HDPE), and the materials were characterized by diffractometry, spectroscopy, microscopy, and calorimetry. During surface modification, reactions between bamboo and silane occurred on the lignin aldehyde group. After 6 wt% KH550 treatment, crystallinity of bamboo was increased by 1.11 %, and melting temperature and enthalpy of the composite rose by 2.37 °C and 5.27 J/g, agreeing with improved interface morphology. Increasing in thickness from 3 to 9 mm, the physical and mechanical properties of composite were improved overall. Bamboo content caused the biggest influence, while thickness swelling exhibited the greatest susceptibility. Increasing the bamboo ratio boosted flexural and tensile properties, but it compromised toughness and water resistance, while silane and moulding parameters featured complicated relationships regarding performances. Combining an artificial neural network (ANN), KH550 3 wt%, moulding temperature of 180 °C, and a time of 8 min endowed 9 mm composites of 70 wt% bamboo with performance comparable to load bearing MDF in GB/T 11718. This research helped establish the first “Bamboo Plastic Composite” standard proposed by the authors for the Chinese forestry industry.
  • Researchpp 5071-5082Chen, N., Zeng, Q., Lin, Q., and Rao, J. (2015). "Effect of enzymatic pretreatment on the preparation and properties of soy-based adhesive for plywood," BioRes. 10(3), 5071-5082.AbstractPDF
    Response surface methodology was employed to determine the effects of enzymatic pretreatment temperature, time, and pH on the reducing sugar content and bonding strength of soy-based adhesives (SBAs). Plywood specimens bonded by the SBAs with Pinus massoniana veneer were then produced. A significant positive correlation was observed between reducing sugar content and the bonding strength of SBAs. The effects of pretreatment temperature and time on bonding strength were also significant, but insignificant with respect to reducing sugar content; the effects of enzymatic pretreatment time on response values were the smallest. The optimal enzymatic pretreatment conditions of SBA were a pretreatment temperature of 54 °C, a pretreatment time of 20.0 min, and a pretreatment pH of 5.1. Under these conditions, the reducing sugar content and bonding strength (boiling-water test) of SBAs were 2.93% and 0.62 MPa, which were higher than the control by 113.9% and 30.6%, respectively. X-ray diffraction (XRD) indicated that the ordered degree of soy protein decreased, but the ordered structure had no variation when defatted soy flour was treated by enzymes with combination of acid, salt, and alkali. The SBAs contain more active functional groups and have better water resistance after curing.
  • Researchpp 5083-5095Yavari, A., and Roohnia, M. (2015). "Quality assessment of scarf joints considering the acoustic parameters: A nondestructive approach," BioRes. 10(3), 5083-5095.AbstractPDF
    The present research studied the acoustic properties of 40 oak timber samples (Quercus castaneifolia): the acoustic coefficient (K) and acoustic conversion efficiency (ACE) in free vibration mode, using the free-free bar method with different planes of vibration, i.e., tangential (LT) and radial (LR). These acoustic parameters were considered for both primary virgin wooden beams and modified beams carrying a single scarf joint in four different bonding angles (60°, 65°, 70°, and 75°), individually glued with two different adhesives (isocyanate and polyvinyl acetate). Comparing the acoustic properties of primary solid beams with scarf jointed beams of oak wood in LT and LR planes, the steeper joint angles of 70° and 75° did not result in any serious changes with polyvinyl acetate adhesive. Scarf-jointed beams with smaller joint angles (60° and 65°) had significant effect on the acoustic properties relative to larger angles. Thus, beams having larger joint angles and beams glued using polyvinyl acetate may have enhanced acoustic properties.
  • Researchpp 5096-5116Daystar, J., Treasure, T., Gonzalez, R., Reeb, C., Venditti, R., and Kelley, S. (2015). "The NREL biochemical and thermochemical ethanol conversion processes: Financial and environmental analysis comparison," BioRes. 10(3), 5096-5116.AbstractPDF
    The financial and environmental performance of the National Renewable Energy Lab’s (NREL) thermochemical and biochemical biofuel conversion processes are examined herein with pine, eucalyptus, unmanaged hardwood, switchgrass, and sweet sorghum. The environmental impacts of the process scenarios were determined by quantifying greenhouse gas (GHG) emissions and TRACI impacts. Integrated financial and environmental performance metrics were introduced and used to examine the biofuel production scenarios. The thermochemical and biochemical conversion processes produced the highest financial performance and lowest environmental impacts when paired with pine and sweet sorghum, respectively. The high ash content of switchgrass and high lignin content of loblolly pine lowered conversion yields, resulting in the highest environmental impacts and lowest financial performance for the thermochemical and biochemical conversion processes, respectively. Biofuel produced using the thermochemical conversion process resulted in lower TRACI single score impacts and somewhat lower GHG emissions per megajoule (MJ) of fuel than using the biochemical conversion pathway. The cost of carbon mitigation resulting from biofuel production and corresponding government subsidies was determined to be higher than the expected market carbon price. In some scenarios, the cost of carbon mitigation was several times higher than the market carbon price, indicating that there may be other more cost-effective methods of reducing carbon emissions.
  • Researchpp 5117-5124Khakifirooz, A., Samariha, A., and Nemati, M. (2015). "Insight on the feasibility of producing durable paper from spruce pulp using the sulfate process," BioRes. 10(3), 5117-5124.AbstractPDF
    Bleached spruce sulfate pulp was used in this study to produce paper handsheets. Ethylene diamine tetra acetic acid (EDTA ( was introduced as a chelating agent in concentrations of 0, 0.25, 0.5, and 0.75%. The handsheets were exposed to UV light at wavelengths ranging from 330 to 440 nm, with time intervals of 0, 10, 20, 30, 40, and 50 h. Finally, the strength properties were measured based on ISO standards. The strength indices of the handsheets were improved by adding the proper concentration of EDTA chelating agent, in comparison with the control sample. Furthermore, increasing the aging time reduced the breaking length, tear strength, folding endurance, burst strength, and tensile strength. Tear index, tensile strength, tearing strength, bursting strength, and folding endurance were decreased respectively by 41.9, 3.1, 28.2, 29.7, and 8.6 percent without EDTA treatment by increasing the aging time.
  • Researchpp 5125-5139Chen, H., Zhang, Y., Wo, Q., Yang, F., Wang, J., Guo, Y., and Zheng, Q. (2015). "Modified PCC used in papermaking processes," BioRes. 10(3), 5125-5139.AbstractPDF
    Alkylketene dimer (AKD), cationic starch (CS), and polyamide epichlorohydrin (PAE) were used in the modification of precipitated calcium carbonate (PCC), and the use of the modified PCC in papermaking was investigated. It was found that after the PCC was modified, the sizing effectiveness of AKD was enhanced; when PAE was added to the filler, it had better modified effects than when CS was added. When the addition of PCC and AKD were fixed at 20% and 1% (based on the dry weight of PCC), respectively, the retention of PCC increased from 42.5% to 54.6% when modified by 5% CS, and to 56.7% when modified by 2% PAE. The strength properties (tensile indices, burst indices, and tear indices), opacity, and air permeability of the filled paper were strikingly enhanced, while the brightness was slightly negatively influenced by the addition of PAE. The results indicate that the pre-blend modified method is a promising technique for papermaking in that it enhanced the properties of paper.
  • Researchpp 5140-5158Matsakas, L., Antonopoulou, I., and Christakopoulos, P. (2015). "Evaluation of Myceliopthora thermophila as an enzyme factory for the production of thermophilic cellulolytic enzymes," BioRes. 10(3), 5140-5158.AbstractPDF
    Enzymatic hydrolysis is a key step in bioethanol production. Efficient hydrolysis requires a consortium of different enzymes that are able to hydrolyze cellulose and hemicellulose into fermentable sugars. Myceliopthora thermophila is a promising candidate for the production of thermophilic cellulolytic enzymes, the use of which could reduce the cost of ethanol production. The growth conditions of the fungus were optimized in order to achieve increased secretion of extracellular cellulases. Optimal conditions were found to be 7.0% w/v brewer’s spent grain as the carbon source and 0.4% w/v ammonium sulfate as the nitrogen source. The cellulases obtained were characterized for their optimum activity. The optimum temperature and pH for cellulase activity are 65 °C and pH 5.5, respectively. Studies on thermal inactivation of the crude extract showed that the cellulases of M. thermophila are stable for temperatures up to 60 °C. At this temperature the half-life was found to be as high as 27 h. Enzymatic hydrolysis of cellulose resulted in 31.4% hydrolysis yield at 60 °C after 24 h of incubation. Finally, the recalcitrance constant for cellulose and cellulose pretreated with ionic liquids was calculated to be 5.46 and 2.69, respectively.
  • Researchpp 5159-5173Icel, B., Guler, G., Isleyen, O., Beram, A., and Mutlubas, M. (2015). "Effects of industrial heat treatment on the properties of spruce and pine woods," BioRes. 10(3), 5159-5173.AbstractPDF
    The purpose of this study was to evaluate the effects of an industrial heat treatment (ThermoWood) based on changes in the strength properties, density, and color of spruce (Picea abies) and pine (Pinus sylvestris) woods. Samples were subjected to heat treatment processes at 212 °C for a duration of 120 min. The results showed that the applied process caused a 2.56 to 6.12% decrease in density. Dimensional stability was considerably improved, with ASE values of 58% and 52% for spruce and pine, respectively. The color became darker after treatment. The process caused a significant (p<0.05) reduction (8 to 42%) for all investigated mechanical properties at a specific moisture level (12%). However, the mechanical properties of wood are closely related to its moisture content, and heat-treated wood is less hygroscopic than untreated wood. It was found that, after long-term acclimatization, heat-treated samples had almost half the equilibrium moisture content of control samples. Because the changes that occurred after this heat treatment are irreversible, it is possible that ThermoWood has lower equilibrium moisture content than untreated wood. Therefore, this should be taken into account when investigating the mechanical design values of heat-treated wood.
  • Researchpp 5174-5190Ratnasingam, J., Ramasamy, G., Toong, W., Senin, A. L., Kusno, M. A., and Muttiah, N. (2015). "An assessment of the carbon footprint of tropical hardwood sawn timber production," BioRes. 10(3), 5174-5190.AbstractPDF
    The demand for sawn timber throughout the world is steady, as wood is one of the most important raw materials available to mankind. Yet, the production of sawn timber through sawmilling activities causes environmental issues and is perceived to have a potential effect on global warming. Studies on this aspect is very limited, especially for tropical hardwoods. The intention for this study was to evaluate the carbon footprint of manufacturing sawn timber from round wood using a gate-to-gate life cycle approach. The functional unit used was 1 m3 of rough green sawn timber. Primary data on yield and energy consumption during the sawmilling process were collected on a monthly basis throughout 2013. Greenhouse gas emissions, which include CO2, CH4, and N2O, were determined using emission factors. The carbon footprint was then calculated on the basis of the equivalency factor, described as CO2-eq. The carbon footprint assessment shows a result of 499 kg CO2-eq/m3 and 696 kg CO2-eq/m3 for Light Red Meranti and Dark Red Meranti sawn timber, respectively. The results showed that there were no significant differences in the carbon footprint of Light Red Meranti and Dark Red Meranti sawn timber production.
  • Researchpp 5191-5202Tanninen, P., Leminen, V., Eskelinen, H., Lindell, H., and Varis, J. (2015). "Controlling the folding of the blank in paperboard tray press forming," BioRes. 10(3), 5191-5202.AbstractPDF
    The press forming process of paperboard trays is challenging. The production of trays that fulfill all functional and visual property requirements is demanding. Blank preparation is an essential part of paperboard tray press forming. The aim of this work was to study how a creasing pattern can be utilized in the compaction and folding of the substrate in tray corners. The investigation of creasing pattern designs focused on the positioning of creases, the optimization of the amount of creases, and the width of the creases. The results of the study show that the amount of creases in the tray corner is the most important variable in the pattern design. The substrate folds more evenly and the wall of the tray is smoother when the material has the optimum amount of folds for it to compact during the press forming process. Changes in the creasing pattern primarily affect the amount of unclosed creases in the flange of the tray, which can make tight lidding of the tray impossible. The outcome of the study is a morphological analysis of the introduced creasing pattern alternatives and a selection of formulas that can be utilized in the creasing pattern design process.
  • Researchpp 5203-5214Han, X., Miao, X., Zheng, X., Xing, L., and Pu, J. (2015). "Chemical modification by impregnation of poplar wood with functional composite modifier," BioRes. 10(3), 5203-5214.AbstractPDF
    Poplar is a fast-growing tree with a short cultivation time; however, there are some disadvantages to poplar such as its low density and low dimensional stability. The aim of this work was to study the physical and chemical performance of poplar wood treated by its impregnation with functional composite modifiers followed by compression drying. The results showed that this approach not only significantly increased the dimensional stability of the wood but also enhanced its bending strength and compressive strength parallel to the wood grain. Fourier transform infrared analysis showed that the intensity of the hydroxyl (-OH) and carbonyl (C=O) absorption peaks decreased, which provided evidence that the –NHCH2OH of the modifier reacted with the wood’s carboxyl and hydroxyl groups. The position of the XRD peaks did not change, which indicated that the crystallinity structure of cellulose was not noticeably affected by chemical modification. The TGA showed that the thermal stability of the modified wood was improved, while FESEM analysis showed that the wood cell lumens and vessels were filled with chemicals.
  • Researchpp 5215-5232Santos, J. I., Fillat, Ú., Martín-Sampedro, R., Ballesteros, I., Manzanares, P., Ballesteros, M., Eugenio, M. E., and Ibarra, D. (2015). "Lignin-enriched fermentation residues from bioethanol production of fast-growing poplar and forage sorghum," BioRes. 10(3), 5215-5232.AbstractPDF
    The current challenges in developing a cost-effective bioethanol industry include the production of not only high-volume, low cost biofuels but also high-value products with minimal downstream waste. The up-grading of side-stream lignins from bioethanol production plants to novel high-value products will improve the profitability of the bioethanol industry; to do that, a precise understanding of lignin is required. In the present study, lignin-enriched fermentation residues from bioethanol production (steam explosion pretreatment, saccharification, and fermentation) of fast-growing poplar and forage sorghum were characterized. In addition to the purity and composition, lignin structure (syringyl/guaiacyl (S/G) ratio, inter-unit linkages) was also analyzed with spectroscopy techniques such as Fourier transform infrared and two-dimensional nuclear magnetic resonance. Bioethanol processing and feedstock origins seemed to be the main factors determining the purity, composition, and structure of lignins. Residual lignins from poplar and forage sorghum contained significant amounts of sugar and protein impurities. Poplar lignin showed a very high S/G ratio associated with p-hydroxybenzoate. A lower S/G ratio together with H lignin units and p-hydroxycinnamates (p-coumarate and ferulate) was observed for forage sorghum lignin. The main inter-unit linkages present in both lignins were β-O-4´ aryl ether followed by resinols and phenylcoumarans.
  • Researchpp 5233-5241Basso, M. C., Lagel, M.-C., Pizzi, A., Celzard, A., and Abdalla, S. (2015). "First tools for tannin-furanic foams design," BioRes. 10(3), 5233-5241.AbstractPDF
    Formaldehyde-free quebracho tannin foams were prepared for the first time. Several simple formulations have been presented in order to study the capital influence of each component on foaming and therefore on the characteristics of the obtained foams. Incorporation of a non-ionic surfactant leads to smaller cells and a more homogeneous cell size distribution. Cross-linking agents improve the mechanical properties of foams. A combination of different catalysts allows control of the ratio between the expansion/hardening processes. The understanding of the roles and interactions of the different components of formulation make possible the design of tannin foams having specific properties.
  • Researchpp 5242-5255Zuo, H. B., Zhang, P. C., Zhang, J. L., Bi, X. T., Geng, W. W., and Wang, G. W. (2015). "Isothermal CO2 gasification reactivity and kinetic models of biomass char/anthracite char," BioRes. 10(3), 5242-5255.AbstractPDF
    Gasification of four biomass chars and anthracite char were investigated under a CO2 atmosphere using a thermo-gravimetric analyzer. Reactivity differences of chars were considered in terms of pyrolysis temperature, char types, crystallinity, and inherent minerals. The results show that the gasification reactivity of char decreased with the increase of pyrolysis temperature. Char gasification reactivity followed the order of anthracite coal char (AC-char) ˂ pine sawdust char (PS-char) ˂ peanut hull char (PH-char) ˂ wheat straw char (WS-char) ˂ corncob char (CB-char) under the same pyrolysis temperature. Two repesentative gas-solid models, the random pore model (RPM) and the modified random pore model (MRPM), were applied to describe the reactive behaviour of chars. The results indicate RPM performs well to describe gasification rates of chars but cannot predict the phenomenon that there appears to exist a peak conversion for biomass chars at a high conversion rate, where the MRPM performs better.
  • Researchpp 5256-5266Wang, F. Y., Li, H. Y., Liu, H. M., and Liu, Y. L. (2015). "Fractional isolation and structural characterization of hemicelluloses from soybean hull," BioRes. 10(3), 5256-5266.AbstractPDF
    Hemicellulosic fractions were extracted from soybean hull with various concentrations of NaOH at 50 °C for 5 h. The chemical compositions and physicochemical properties were determined by high performance anion exchange chromatography (HPAEC), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyzer (TGA), and 13C and 2D nuclear magnetic resonance (NMR) analysis. The crystallinity of soybean hulls treated and untreated by alkali liquid was examined by X-ray diffraction (XRD). The sugar analysis results indicated that all of the hemicellulosic preparations were heteropolysaccharides containing arabinose, galactose, glucose, xylose, and mannose. According to the spectral analysis, hemicelluloses from soybean hull were assumed to be L-arabino-4-O-methyl-D-glucurono-D-xylan. Xylose was the predominant monosaccharide in the hemicellulose fraction 1 (H1), and it ranged between 40.1% and 48.8% of the total neutral sugars. It was found that hemicellulose fraction 3 (H3) had the highest thermal stability and H1 had the lowest thermal stability. The crystallinity index (CrI) was found to be about 20.8%, 14.3%, 10.9%, and 4.7% for soybean hulls, untreated and treated with 1.5, 2.0, and 2.5 M NaOH, respectively.
  • Researchpp 5267-5277He, Z., Wang, Z., Lv, H., Zhang, Z., and Yi, S. (2015). "Effects of ultrasound on mass transfer within the boundary layer during wood vacuum drying," BioRes. 10(3), 5267-5277.AbstractPDF
    Ultrasound was applied to enhance mass transfer within the boundary layer during wood vacuum drying. Fast growing poplar (Populus tomentosa) was used as the specimen in this work. The water migration rates and the mass transfer coefficients were studied at temperatures of 35 and 50 °C, absolute pressures of 0.03, 0.06, and 0.1 MPa, and ultrasound power-frequency groups of 60 W-28 kHz, 100 W-28 kHz, and 100 W-20 kHz, respectively. The results indicated that ultrasound could markedly increase the water migration rates within the boundary layer. The water migration rates increased with increasing ultrasound power and frequency. The mass transfer coefficients within the boundary layer for specimens treated with ultrasound were much higher than those of the control group, and the mass transfer coefficients increased with decreasing absolute pressure. Ultrasound could be applied in the wood drying industry as a means of saving time and energy.
  • Researchpp 5278-5292Li, C., Wang, Q., Liu, M., and Wang, H. (2015). "Rheological behaviors of polymer impregnated maple veneer," BioRes. 10(3), 5278-5292.AbstractPDF
    The objective of this study was to determine rheological behaviors of maple veneer plastic composite (MVPC) prepared by full cell preparation technology through the use of a rotational rheometer. The results showed that at 25 to 105 °C, the storage modulus G' and loss modulus G'' of the MVPC were apparently higher than that of the control. In the range 105 to 210 °C, the storage modulus G' of the MVPC was basically the same as that of the control, and the loss modulus G'' was slightly higher than that of the control. At 105 °C, the Tanδ curve of the MVPC had an obvious peak, which indicated that the glass transition temperature (Tg) of the MVPC was about 105 °C. The rheological behavior of the MVPC with different impregnation weight gain rates showed that the MVPC with a 55% impregnation weight gain rate had higher G', G'', and Tanδ.
  • Researchpp 5293-5304Guan, X., Shi, J., Guo, M., Lin, J., Liu, X., and Li, J. (2015). "Preparation of medium density fiberboard from wood fibers catalytically oxidized by laccase-mediator system," BioRes. 10(3), 5293-5304.AbstractPDF
    Laccase, an enzyme capable of degrading lignin, has become an effective agent for green processing and has great significance for the protection of the environment and the development of a low-carbon economy. In this work, wood fibers were selected as the raw material, and with activation by a laccase-mediator system, lignin was changed to a natural adhesive material, and the high temperature/high pressure method was used to prepare medium density fiberboard (MDF). The bonding mechanism was explored with measurements of Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), environmental scanning electron microscope (ESEM), and X-ray diffraction (XRD). It was found that the self-adhesive effect was realized through esterification, hydrogen bonding, polycondensation, coupling, and a Schiff base reaction, among which coupling and polycondensation were the primary reactions. The chemical bonds between the MDF interior and surface varied because of the mobility of the lignin during the reaction.
  • Researchpp 5305-5316Sri Aprilia, N. A., Sohrab Hossain, M., Mustapha, A., Suhaily, S. S., Noruliani, N. A. N., Peng, L. C., Omar, A. K. M., and Abdul Khalil, H. P. S. (2015). "Optimizing the isolation of microfibrillated bamboo in high pressure enzymatic hydrolysis," BioRes. 10(3), 5305-5316.AbstractPDF
    Bleached bamboo fiber was treated with a high pressure enzymatic hydrolysis (HPEH) process in order to produce microfibrillated bamboo fiber (MBF). Mixture design of experiments was utilized to determine the optimal constituents of fiber, enzymes, and water for the HPEH process on the isolation yield of the MBF. Results showed the optimal combination for the maximal yield isolation of the MBF was 1 g fiber, 1 g enzyme, and 1 L water at 90 MPa and 70 °C. The influence of the reaction time of the HPEH process (6 to 48 h) was also evaluated in this study. Morphological and thermal property analyses of untreated and treated bamboo fibers revealed that the HPEH process was effective for removing non-cellulosic components from the fibers. Thus, the HPEH process is an effective method for the isolation of the MBF, with the benefits of elevated crystallinity and thermal stability.
  • Researchpp 5317-5329Ebadi, S. E., Karimi, A., Choo, A. C. Y., Ashari, Z., Naji, H. R., Soltani, M., and Ridzuan, S. M. A. (2015). "Physical behavior of hydro-thermally treated oil palm wood in different buffered pH media," BioRes. 10(3), 5317-5329.AbstractPDF
    This study investigated changes in the physical properties of oil palm (Elaeis guineensis) wood (OPW) using various buffered media for the hydrothermal treatment process. The buffered media were prepared separately for three different treatment conditions: pH of 8, pH of 5, and tap water. These treatments were compared with unbuffered, control samples. The OPW samples were taken from the outer part of the trees. The OPW samples were treated with the buffered media at a temperature of 140 °C for 120 min. The parameters evaluated were wood density (ρ), equilibrium moisture content (EMC), mass loss (ML), water absorption (WA), volumetric swelling (SV), anti-swelling efficiency (ASE), and water repellent efficiency (WRE), for both treated and untreated samples. The buffered media significantly affected the EMC (%), ρ (g/cm3), ML (%), and WA (%), with no significant effects on the ASE (%) and WRE (%). It was concluded that the hydrothermal treatment in the buffered medium with a pH of 8 had the most significant effect on the physical properties of OPW.
  • Researchpp 5330-5344Mansour, M. M. A., Salem, M. Z. M., Khamis, M. H., and Ali, H. M. (2015). "Natural durability of Citharexylum spinosum and Morus alba woods against three mold fungi," BioRes. 10(3), 5330-5344.AbstractPDF
    The natural durability of wood to mold fungi was tested under laboratory conditions with locally sourced Citharexylum spinosum and Morus alba woods. The mold fungi were Penicillium selerotigenum, Paecilomyces variotii, and Aspergillus niger. Changes in surface elemental composition were evaluated with energy dispersive X-ray spectroscopy (EDX) and the biodeterioration of wood surfaces by scanning electron microscope (SEM). The C peak element of C. spinosum wood was affected significantly (P = 0.0004) and decreased from 49.91% in the control specimens to 47%, 40.1%, and 40% with P. selerotigenum, A. niger,and P. variotii,respectively.Also, the C peak element of M. alba heartwoodsignificantly decreased (P < 0.0001) from 51.33% in the control specimens to 41.49%, 45.66%, and 43.66% in wood inoculated with A. niger, P. variotii,and P. selerotigenum,respectively. The elements Al and Cu were observed in high percentages with M. alba heartwoodinoculated by P. variotii. The methanol extract from M. alba heartwood showed good inhibition against the growth of A. niger at a concentration of 32 μg/mL, and the methanol extract from C. spinosum woodshowed remarkable inhibition against the growth of P. variotii at a concentration of 8 μg/mL. The results of this study clearly showed the changes that occur in wood samples as a result of fungal infestation.
  • Researchpp 5345-5355Delgado-Aguilar, M., González, I., Tarrés, Q., Alcalà, M., Pèlach, M. A., and Mutjé, P. (2015). "Approaching a low-cost production of cellulose nanofibers for papermaking applications," BioRes. 10(3), 5345-5355.AbstractPDF
    The use of cellulose nanofibers (CNF) as an additive in papermaking is an attractive alternative to improve paper’s strength. However, the costs of CNF production need to be competitive compared to other approaches aimed at reducing mechanical beating. Five different types of CNFs were prepared following different pretreatments: TEMPO-mediated oxidation at basic and neutral conditions, soft acid hydrolysis, enzymatic treatment, and mechanical beating. All of the pretreated fibers were later passed through a high-pressure homogenizer. The resulting CNFs were each applied to a papermaking pulp to investigate their reinforcing ability. Results indicated that the TEMPO-oxidized CNFs offered the highest increase at the same nanofiber content compared to the other types of CNFs. However, an analysis of the cost of increasing paper’s breaking length by 75% indicated that TEMPO-oxidized CNFs were more expensive than the other CNF grades, whereas CNFs from mechanical and acid pre-treatment offered similar increases at lower prices. The results indicated that CNFs of high fibrillation degree were not necessary to induce dramatic increases in paper strength. This finding offers a new possibility for the escalation of CNF production to industrial levels with competitive prices.
  • Researchpp 5356-5368Zhang, Y., Kou, R., Lv, S., Zhu, L., Tan, H., Gu, J., and Cao, J. (2015). "Effect of mesh number of wood powder and ratio of raw materials on properties of composite material of starch/wood powder," BioRes. 10(3), 5356-5368.AbstractPDF
    Utilizing wood powder and corn starch as the main materials with polyurethane adhesive as a cross-linking agent, the starch/wood powder composite material was prepared via molding forming techniques. The effects of wood powder mesh and addition of wood powder on the properties of composite material were investigated. The compatibility of starch and wood powder and the thermal stability of composite were evaluated by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMA), respectively. The mechanical properties and water absorption of composite material were also tested. The results showed that the mechanical properties and water resistance of composite material first increased and then fell with increasing mesh, and the best performance was obtained when the mesh ranged from 80 to 100. The best compatibility, mechanical properties, water resistance, and thermal stability of composite material was obtained with 10% polyurethane crosslinking agent addition.
  • Researchpp 5369-5380Zhang, J., Luo, H., Pizzi, A., Du, G., and Deng, S. (2015). "Preparation and characterization of grinding wheels based on a bioresin matrix and glass sand abrasives," BioRes. 10(3), 5369-5380.AbstractPDF
    A 100% renewable, easily-prepared, and industrialized abrasive grinding wheel was produced based on a biobased thermosetting resins matrix; the matrix was made of condensed tannin-furanic resin, originating from biosourced raw materials such as tree barks and crops, which bond the particles of glass sand. These grinding wheels exhibited no cracks or pores. Moreover, the related properties of these products were characterized by the measurements of compression resistance, Brinell hardness, and wear resistance; the results were comparable to those of commercial grinding wheels prepared with synthetic phenolic resins and aluminum oxide particles. The results indicated that incomparable hardness and strong resistance towards compression can be obtained using the new tannin-based grinding wheels. Besides that, the results also revealed excellent properties of abrasiveness when compared to a commercial Taber Calibrade wheel H-18.
  • Researchpp 5381-5394Hlásková, L., Orlowski, K. A., Kopecký, Z., and Jedinák, M. (2015). "Sawing processes as a way of determining fracture toughness and shear yield stresses of wood," BioRes. 10(3), 5381-5394.AbstractPDF
    A new computational model, based on fracture mechanics, was used to determine cutting forces. Unlike traditional computing methods, which depend on many coefficients reflecting the machining of solid wood, the new model uses two main parameters: fracture toughness and shear yield stresses. The aim of this study was to apply this new method to determine these parameters for the tooth cutting edge principal positions and longitudinal and perpendicular cutting speed directions. Samples of beech wood (Fagus sylvatica L.) were sawn. The measurements of energetic effects (cutting power and cutting force) while sawing wood were carried out on two laboratory stands: the sash gang saw and the circular sawing machine. The basic relationships between different sawing methods, such as cutting on a frame sawing machine (sash gang saw) and a circular sawing machine, and the fracture toughness and shear yield stresses were recognizable. The data obtained could be applied to the computation of the energetic effects on other wood cutting methods.
  • Researchpp 5395-5406Wang, Q., Zhang, C., Yao, R., Xu, S., Zhong, J., Luo, L., and Wang, Y. (2015). "Butanol fermentation by Clostridium saccharobutylicum based on poplar wood," BioRes. 10(3), 5395-5406.AbstractPDF
    As a potential source of liquid fuels, lignocellulosic material is an alternative to plant-derived starch and sugar, which are urgently needed to meet global demands for food. The utilization of wood as feedstock for bioconversion to biobutanol fuel not only could reduce production costs, but also could increase raw material supply. However, little is known about biobutanol fermentation based on lignocellulosic material from wood. In this paper, biobutanol fermentation from poplar wood hydrolysates by Clostridium saccharobutylicum was investigated under three different conditions. The desired biobutanol and ABE yields reached 6.98 and 9.64 g/L, respectively, and 69.8 g biobutanol and 96.4 g ABE per kg of poplar wood were achieved. Fermentation of hydrolysates with no additives and with extra mixed carbon sources to biobutanol was also studied. The predicted results were confirmed: in the former, the production of biobutanol and ABE were 4.88 and 6.63 g/L, respectively; in the latter, the biobutanol and ABE yields reached 7.28 and 10.18 g/L, respectively. The results indicated that poplar wood is a potential renewable raw material suitable for biobutanol production, and that Clostridium saccharobutylicum BAA-117 is a promising biobutanol producer for such conversion.
  • Researchpp 5407-5416Tutuş, A., Kazaskeroğlu, Y., and Çiçekler, M. (2015). "Evaluation of tea wastes in usage pulp and paper production," BioRes. 10(3), 5407-5416.AbstractPDF
    The objective of this study was to characterize the properties of pulp and paper produced from tea (Camellia sinensis) wastes, an agricultural residue widely available in Turkey, using the kraft-anthraquinone (AQ) cooking method. The chemical components and fiber morphology of tea wastes were investigated. The results indicated that tea wastes had low holocellulose, cellulose, and α-cellulose contents and high lignin content. Also, the suitability of the fiber for pulp and paper production was examined, and the fiber length, fiber width, lumen diameter, and cell wall thickness were measured. According to these values, it was found that the strength properties of papers obtained from tea wastes were insufficient. Therefore, tea waste pulps were mixed with Turkish pine pulps at various ratios. Twelve different cooking experiments were performed on the tea wastes, and the cooking with the best pulp yield was used for mixing. The second cooking, with 0.1% AQ, gave the best yield (33.26%), an increase of about 3.51% compared to the first cooking with no AQ. The physical and optical properties of the papers were also examined. Results showed that paper properties were improved by increasing the Turkish pine pulp rate. Consequently, tea wastes can be used in pulp and paper production when combined with softwood pulps.
  • Researchpp 5417-5425Tuong, V. M., and Chu, T. V. (2015). "Improvement of color stability of Acacia hybrid wood by TiO2 nano sol impregnation," BioRes. 10(3), 5417-5425.AbstractPDF
    In this study, the TiO2-impregnation of wood from acacia hybrid (Acacia mangium x auriculiformis) was achieved by combined pressure-impregnation and hydrothermal post-treatment. The ultraviolet (UV) resistance of the obtained TiO2-impregnated wood was examined by measuring the changes in color after 960 h of UV irradiation. Results showed that the color stability against UV irradiation of the TiO2-impregnated wood was significantly improved compared to that of the untreated acacia hybrid wood. Furthermore, the prepared wood samples were characterized using a field-emission scanning electron microscope (FE-SEM), energy-dispersive X-ray (EDX) spectroscopy, and X-ray diffraction (XRD) techniques. FE-SEM and EDX analyses showed that the TiO2 micro- and nanoparticles, with rod-like shapes, were located on the inner surfaces of the wood vessels. Additionally, the crystal structure of the TiO2, with an anatase phase, was demonstrated by XRD analysis. This study suggests that the presence of an anatase TiO2 can improve the UV resistance of fabricated wood samples.
  • Researchpp 5426-5439Lv, S., Tan, H., Gu, J., and Zhang, Y. (2015). "Silane modified wood flour blended with poly(lactic acid) and its effects on composite performance," BioRes. 10(3), 5426-5439.AbstractPDF
    The aim of this work was to study silane-modified wood flour/poly(lactic acid) (PLA) blends and the effect of blending on the properties of the wood flour/PLA composites. The surface of the wood flour used as filler was successfully modified by silane, as demonstrated by Fourier transform infrared spectroscopy (FTIR) results. The influence of silane types and content on the morphology, mechanical properties, and water absorption were studied. Scanning electron microscopy (SEM) results demonstrated that the KH-550 silane was the most effective modifier for improving the compatibility, mechanical properties, and water absorption of the blend. The appropriate additive content was 1.5% (relative to wood flour content). As the KH-550 content increased, the mechanical strength and elongation at the break first increased and then slightly decreased. These properties reached a maximum at 1.5% KH-550. The water resistance of the blend also was improved at a KH-550 content of 1.5%.
  • Researchpp 5440-5459Jia, X., Zhao, J., and Cai, Y. (2015). "Radio frequency vacuum drying of timber: Mathematical model and numerical analysis," BioRes. 10(3), 5440-5459.AbstractPDF
    The mass and heat transfer mechanisms during radio frequency/vacuum (RF/V) drying of square-edged timber were analyzed and discussed in detail. Based on the mass and heat transfer theory of porous materials, a one-dimensional mathematical model was developed from conservation equations. Compared with conventional models, it has the following advantages: (1) Each independent variable has a separate governing equation and is solved independently by converting the partial differential equation into a difference equation with the finite volume method; and (2) The calculated data from different parts of the wood specimen are displayed in the evolution curves because the specimen is divided into several units along fiber direction. Therefore, the change law of the parameters can be better described. The software Matlab, which has the advantages of fast calculation speed and high precision, was used for programming and calculations. In addition, the square-edged timber Sugi specimen was dried in a laboratory RF/V dryer, and the total average moisture content (MC) and local temperature were monitored as a function of time. By analyzing the calculated and experimental results, it can be concluded that most of the important phenomena observed during RF/V drying can be adequately described by this model.
  • Researchpp 5460-5475Lyytikäinen, K., and Backfolk, K. (2015). "Xylanase-induced liberation of negatively charged species and their effect on colloidal interactions and the retention of bleached kraft pulp fibers," BioRes. 10(3), 5460-5475.AbstractPDF
    The ability and specificity of various monocomponent endo-1-4-β-xylanases to release negatively charged species from never-dried, bleached, birch kraft pulp was studied. The effects of dissolution of these xylan-based components on pulp filtrate properties and the subsequent chemical retention were determined. The results revealed that the amount of charged species released depended on the xylanase and that the ratio of charged species released to dissolved xylan is not linear. Chemical retention tests showed that high levels of dissolved xylan interfere with the fixation of colloidal species, which was confirmed by removing the dissolved hemicelluloses. The roles of residual hemicellulose and the properties of modified fibers on chemical retention and the level of internal sizing are discussed.
  • Researchpp 5476-5488Gao, S., Han, G., Jiang, W., Zhang, Y., and Zhang, X. (2015). "Steam explosion and alkali-oxygen combined effect for degumming of kenaf fiber," BioRes. 10(3), 5476-5488.AbstractPDF
    Kenaf is an economically viable and ecologically friendly cellulose source. It can be used in the textile, paper, and bio-energy industries, but it has not been effectively developed and utilized because of degumming problems. To effectively take advantage of kenaf resources, to satisfy the growing demand for natural fiber, and to provide support for other fiber material degumming, steam explosion (STEX) pretreatment followed by alkali-oxygen treatment was studied. The effect of pressure on the properties of kenaf during the STEX treatment was studied, and the optimal degumming process for kenaf was selected. Results showed that STEX pretreatment removed pectin and part of the hemicellulose. Carbohydrates (cellulose and hemicellulose) could be degraded via high pressure treatment. The residual gum content and the fineness of the kenaf fiber after the alkali-oxygen treatment were good enough for textile production. High pressure was found not to be a key factor influencing the degumming process. Low pressure STEX (0.5 MPa) and alkali-oxygen treatment was judged to be an efficient method for degumming kenaf fibers.
  • Researchpp 5489-5502Mandić, M., Porankiewicz, B., and Danon, G. (2015). "An attempt at modelling of cutting forces in oak peripheral milling," BioRes. 10(3), 5489-5502.AbstractPDF
    An attempt was made to evaluate the non-linear, multi-variable dependency between the main (tangential) force, FC, and machining parameters and properties of pedunculate oak (Quercus robur) during straight edge, peripheral milling. The tangential force, FC, was found to be influenced by the feed rate per tooth, fZ, cutting depth, cD, rake angle γF, Brinell hardness, H, bending strength, RB, and modulus of longitudinal elasticity, E. Several interactions between machining parameters and properties of wood were confirmed in the developed relationship FC = f(fZ, cD, γF, H, RB, E).
  • Researchpp 5503-5514Cheng, Z., Yang, R., Wang, B., and Yang, F. (2015). "Chlorophenol degradation in papermaking wastewater through a heterogeneous ozonation process catalyzed by Fe-Mn/sepiolite," BioRes. 10(3), 5503-5514.AbstractPDF
    Heterogeneous Fe-Mn/sepiolite catalysts were prepared by the co-precipitation method, followed by heat treatment. The catalysts were characterized by several techniques; analysis by X-ray fluorescence (XRF) and scanning electron microscopy (SEM) confirmed the existence of fine Fe and Mn particles in the catalysts. Compared to natural sepiolite, the specific surface area of the Fe-Mn/sepiolite catalyst was increased from 125.2 to 412.7 m2/g, as measured by Brunauer-Emmett-Teller (BET) analysis. The activity of the catalysts was evaluated by the ozonation degradation of p-chlorophenol solution, and the results showed that the catalysts were highly effective, as the removal rate of p-chlorophenol was more than 98.5%, achieved in 25 min at a 20% (w/w) Mn content. The catalysts were then used for chlorophenol degradation in papermaking wastewater through a heterogeneous ozonation process. At optimal conditions, a 98% chlorophenol removal rate and a 58% COD removal efficiency were achieved in 30 min, and pollutants in the treated wastewater were more biodegradable and less toxic than in raw water. Moreover, the prepared catalysts remained stable during successive catalytic ozonation runs. The possible reaction pathway was also proposed.
  • Researchpp 5515-5531Gong, C., Lu, D., Wang, G., Tabil, L., and Wang, D. (2015). "Compression characteristics and energy requirement of briquettes made from a mixture of corn stover and peanut shells," BioRes. 10(3), 5515-5531.AbstractPDF
    Corn stover and peanut shells are both abundantly available biomass feedstocks in China. To determine the compression characteristics and energy requirement of briquettes, mixtures of the corn stover and peanut shells were compressed under three different pressures (30, 60, and 90 MPa) with three moisture contents (9%, 14%, and 19%, wet basis) and five corn stover-peanut shell mixtures (0%-100%, 25%-75%, 50%-50%, 75%-25%, and 100%-0%) by mass. The results showed that applied pressure, moisture content, and the corn stover-peanut shell mixture all significantly affected briquette density and specific energy consumption. The density of the briquette ranged from 646 to 1052 kg/m3 and the specific energy consumption varied from 6.6 to 25.1 MJ/t. A moisture content of 9% was found to be better for the compression of the corn stover and peanut shells mixture. Adding peanut shells to the corn stover improved briquette density and reduced the specific energy consumption. Linear models were developed to describe the briquette density and the specific energy consumption. The briquette durability ranged from 57% to 94% and durable briquettes can be obtained when corn stover and peanut shells are compressed with the mixing ratio of 1:1 (50%-50%) at moisture content of 9%.
  • Researchpp 5532-5543Tan, B. K., Ching, Y. C., Gan, S. N., and Rozali, S. (2015). "Biodegradable mulches based on poly(vinyl alcohol), kenaf fiber, and urea," BioRes. 10(3), 5532-5543.AbstractPDF
    This paper describes the preparation of poly(vinyl alcohol)/kenaf fiber (PVOH/KF) composites with entrapped urea. The major FTIR peaks of these composites could be identified. These composites are intended for agricultural applications as biodegradable mulches and could be potential carrier materials for fertilizer. The water solubility, release behavior, chemical properties, and thermal stability of the composites were evaluated. The composites lost 25% of their weight after 7 days in water. In a wet environment, urea was released from the composites through its dissolution in water, and around 57% of the urea was released from the composites in 24 h; Thermagravimetric analysis showed that these composites were stable up 150 °C. These composites would be able to withstand rain and protect seedlings from the sun when applied in the field as mulches. For around three to four weeks, these biobased mulches could slowly disintegrate as the PVOH binder was gradually dissolved by moisture, releasing the kenaf fibers to serve as soil fertilizer without leaving any undegradable waste for disposal. Hence, they would not pose any risks to the land or biological systems.
  • Researchpp 5544-5553Gejdoš, M., Lieskovský, M., Slančík, M., Němec, M., and Danihelová, Z. (2015). "Storage and fuel quality of coniferous wood chips," BioRes. 10(3), 5544-5553.AbstractPDF
    Wood chips from Norway spruce (Picea abies L.) and silver fir (Abies alba L.) were stored for a period of 15 months (experimental pile was 4.0 m high). Atmospheric temperature and the temperature inside the pile at heights of 1, 2, and 3 m were measured in regular intervals. Samples were taken from an assortment of heights at the beginning and the end of the experimental period. Subsequently, the samples were subjected to an analysis of moisture content and other properties such as calorific value (according to the standard STN ISO 1928:2003 and ÖNORM M 7132) and ash content (according to the standard STN ISO 1171). The most significant decrease in the chips’ moisture content, and increase in the calorific value from the beginning of storage, was at the height of 1.0 m. An increase in the moisture content and decrease in calorific value was recorded for samples taken from the height of 3.0 m. Samples taken from this height showed an increase in ash content after a 15-month storage period. The experiment described the influence of specific weather conditions on the development of temperature, calorific value, and ash content of coniferous wood chip piles with particle size up to 35.5 mm.
  • Researchpp 5554-5562Kılıç, M. (2015). "Effects of machining methods on the surface roughness values of Pinus nigra Arnold wood," BioRes. 10(3), 5554-5562.AbstractPDF
    In this study, samples were subjected to the following surface treatment techniques: sawing with a circular saw, planing with a thickness machine, and sanding with a sanding machine (with No. 80 sandpaper). After samples were treated radially and tangentially with machines, their surface roughness values (Ra, Ry, and Rz) were measured according to ISO 4288. When statistics related to surface roughness values (for Ra, Ry, and Rz) were analyzed, it was found that surfaces processed with the thickness machine exhibited the smoothest surfaces. Also, according to the same statistical tables, the lowest surface roughness values were found for surfaces cut tangentially.
  • Researchpp 5563-5572Pňakovič, L., and Dzurenda, L. (2015). "Combustion characteristics of fallen fall leaves from ornamental trees in city and forest parks," BioRes. 10(3), 5563-5572.AbstractPDF
    Combustion characteristics of leaves fallen off ornamental trees in city and forest parks were evaluated. The moisture content of the leaves at the time of falling was between Wr = 36.1 and 46.9%. The average contents of the individual elements in the combustible material were Cdaf = 48.1%, Hdaf = 6.1%, Ndaf = 1.2%, Sdaf = 0.1%, and Odaf = 44.6%. The resulting ash from the dry leaves varied between Ad = 4.8 and 13.1%. The heat of combustion of the dry leaves was between Qs = 16,046 and 20,247, and the lower heating value was between Qn = 13,479 and 19,120 The results were compared with dry firewood of hard deciduous trees. The higher heating value of the dry leaves was 11.7% lower and the lower heating value was also lower by 15.1%. The decline of these basic combustion characteristics is caused mostly by its high ash content and to a smaller extent by the increased nitrogen content.
  • Researchpp 5573-5585Adamopoulos, S., Foti, D., Voulgaridis, E., and Passialis, C. (2015). "Manufacturing and properties of gypsum-based products with recovered wood and rubber materials," BioRes. 10(3), 5573-5585.AbstractPDF
    The experimental production of gypsum-based products (cylindrical samples, solid bricks) using different fractions of wood chips and rubber particles was studied. Recovered rubber and wood materials were mixed with gypsum and water in various proportions to fabricate gypsum-wood and gypsum-rubber cylindrical samples and standard solid bricks with six holes using appropriate molds. It was shown that to manufacture gypsum-wood and gypsum-rubber products with good mechanical strength, coarse fractions of wood and rubber should be used, but the proportion of wood or rubber should not exceed 25%. No thermal conductivity differences were found between the wood- and rubber-type of gypsum products, and particle size and material proportion had no effect. Samples with fine wood and rubber particles present at a lower proportion (25%) exhibited similar sound absorption behavior. The solid bricks had slightly higher strength when loaded at the large surface of their lateral upper side than when loaded at the small surface. The bricks provided better thermal insulation than both the extruded and pressed house bricks but lower than that of insulating bricks. The emission of volatile organic compounds out of the bricks was at an acceptable level according to regulations for construction products.
  • Researchpp 5586-5595Cai, X., Ren, R., Zhang, M., Jin, X., and Zhao, Q. (2015). "Preparation of nitrogen-containing activated carbon from waste medium density fiberboard for electric double layer capacitor," BioRes. 10(3), 5586-5595.AbstractPDF
    The waste of medium density fiberboards was carbonized at a temperature of 500 °C. The activated carbons were obtained after 16 h of impregnation and 1 h of activation by KOH at 800 °C with KOH/coke mass ratios of 2.5, 3.0, 3.5, and 4.0. The activated carbons were investigated for determination of porosity and elemental analysis. The results showed that the surface area of the activated carbons varied from 1456 to 1647 m2/g and the total pore volume ranged from 0.701 to 1.106 cm3/g, which was affected by different KOH/coke mass ratios . The pore size distribution indicated that waste medium density fiberboard activated carbons included both micropores and mesopores, and the elemental analysis implied that the contents of nitrogen varied from 0.97% to 2.60%. Electric double layer capacitors were made using the activated carbons and their electrochemical properties were studied. The specific capacitances of the activated carbon electrodes ranged from 212 to 223 F/g. The results suggest that activated carbon from waste medium density fiberboard can be a candidate material for electric double layer capacitor electrodes because of its good electrochemical capacities.
  • Researchpp 5596-5606Wang, S., Chen, F., and Song, X. (2015). "Preparation and characterization of lignin-based membrane material," BioRes. 10(3), 5596-5606.AbstractPDF
    Lignin-based membrane material was prepared from lignosulfonate extracted from sulfite pulping. The effects of formaldehyde, polyvinyl alcohol (PVA), urea, borax, glutaraldehyde (GD), and dimethyl phthalate (DMP) on tensile strength and water absorption were investigated. The experimental results showed that the optimum conditions were as follows: a reaction temperature of 85 °C, 22.22 wt.% lignosulfonate, 1.59 wt.% borax, 22.22 wt.% urea, 31.75 wt.% formaldehyde, 22.22 wt.% PVA, 32.32 wt.% GD (to PVA glue), and 32.32 wt.% DMP (to PVA glue). Under these conditions, the tensile strength reached 2.2 ×104 Pa and the water absorption was 35.2%. The products were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that the product components were compatible in this system, and the introduction of cross-linking agents may have resulted in a decrease in pore size.
  • Researchpp 5607-5619Liu, Y., Guo, H., Gao, J., Zhang, F., Shao, L., and Via, B. K. (2015). "Effect of bleach pretreatment on surface discoloration of dyed wood veneer exposed to artificial light irradiation," BioRes. 10(3), 5607-5619.AbstractPDF
    To investigate the effect of bleach pretreatment on the surface photo-discoloration of dyed wood, two kinds of bleached and unbleached dyed wood veneers were irradiated in a xenon light source accelerated aging tester. The exposed surfaces’ color, spectral reflectivity, chemical functional groups, and microstructure were characterized. Bleach pretreatment improved the dyeing effect of the wood veneers. However, it decreased the light fastness of the samples, and as adsorption between the dyes and wood components was reduced, some chromophoric chemical structures of the wood lignin and dyes were degraded, and some extractives (which can function as antioxidants to protect wood surfaces from discoloration) were removed. After light irradiation, the reflectance curves of dyed wood veneers was shifted toward longer wavelengths and noticeable yellowing was observed. Some parenchyma tissue, such as pit membranes in wood cell walls, suffered serious deterioration, as indicated by SEM.
  • Researchpp 5620-5632Liu, W., Yang, L., and Lv, X. (2015). "High-permeability filter paper prepared from pulp fiber treated in NaOH/urea/thiourea system at low temperature," BioRes. 10(3), 5620-5632.AbstractPDF
    Pulp fibers were treated in aqueous NaOH/urea/thiourea solution at low temperatures (from -14 °C to 8 °C) to prepare high-permeability filter papers. The effects of treatment temperature and time were investigated to control the permeability of the filter paper. SEM images were taken to observe the physical configuration of fibers, and fiber quality analysis was used to characterize the properties of the fibers. The main parameters of the filter papers (permeability and bulk) were increased markedly. The permeability was increased from 150.1 L/(m2·s) for the untreated paper to 1136 L/(m2·s) for the treated paper, and from 4.3 cm3/g for the untreated paper to over 5.5 cm3/g for the treated paper. The zero-span tensile strength changed only slightly. Moreover, the characteristics of the pulp fibers underwent some positive changes. These results demonstrate that the permeability of paper sheets can be preferably improved by treating fibers in NaOH/urea/thiourea solution at -2 °C for 30 min.
  • Researchpp 5633-5654Haghdan, S., Tannert, T., and Smith, G. D. (2015). "Wettability and impact performance of wood veneer/polyester composites," BioRes. 10(3), 5633-5654.AbstractPDF
    Fiber-reinforced thermosetting composites have been of interest since the 1940s due to their ease of use in processing, fast curing times, and high specific stiffness and strength. While the use of plant fibers in a polyester matrix has been thoroughly studied, only limited information is available regarding using wood as reinforcement. In this study, composites of thin wood veneer and a polyester matrix were made and the difficulties in the lamination and curing processes were investigated. Sheets of Douglas fir, maple, and oak veneers using a catalyzed polyester resin were assembled as unidirectional, balanced, and unbalanced cross-ply laminates. These were compared to control specimens using glass fiber as reinforcement. The impact properties of the samples, with respect to the laminate thicknesses, were characterized using a drop-weight impact tester. The wettability and surface roughness of unsanded and sanded wood veneers were also investigated. Results showed that Douglas fir cross-ply laminates had an impact energy equivalent to glass fiber laminates, making them an interesting alternative to synthetic fiber composites. Wood/polyester laminates absorbed a considerable amount of energy through a higher number of fracture modes. The balanced lay-up limited twisting of the wood/polyester composites. The lowest contact angle and highest wettability were observed in unsanded Douglas fir veneers.
  • Researchpp 5655-5665Fan, H., Liu, P., Liu, J., and Xu, B. (2015). "Effect of hydrodynamic shear on agglomerated ground calcium carbonate filler after surface modification with starch and its effects on paper properties," BioRes. 10(3), 5655-5665.AbstractPDF
    Ground calcium carbonate (GCC) was modified with starch, sodium stearate, and sodium hexametaphosphate prior to the papermaking process. This paper is focused on the effect of shear on the modified GCC and considers the impact of adding modified GCC into paper. The coating efficiency of starch on GCC was investigated in terms of the shear-tolerance of the agglomerated filler. Experimental results showed that the precipitation temperature and the amount of crosslinking agent, sodium hexametaphosphate, both were important relative to shear tolerance. Lower precipitation temperature was beneficial for the starch coating. Within a certain range, more sodium hexametaphosphate led to a stronger complex. The results showed that 1.5% (based on MGCC) of sodium hexametaphosphate and a precipitation temperature of 60 °C were the optimum conditions for shear tolerance.
  • Researchpp 5666-5676Zhan, H., Tan, G., Wang, C., and Wang, S. (2015). "Chemical properties and fiber morphology of Fargesia fungosa at different culm ages and heights," BioRes. 10(3), 5666-5676.AbstractPDF
    The chemical properties and fiber morphology of Fargesia fungosa at different culm ages and height portions were investigated. The variations in moisture, ash, SiO2, and toluene–alcohol extractive contents with culm ages were greater than they were with heights. The holocellulose varied neither significantly with age nor with height. The fiber length, width, length-to-width ratio, and wall thickness of F. fungosa increased with culm ages. Meanwhile, the middle portions of culms at all age classes had the highest values of fiber length and width. The lumen diameter decreased, whereas the wall-lumen ratio increased, with increasing bamboo ages and heights. The 3-year-old culms of F. fungosa are suitable for pulp and papermaking based on their fine chemical properties and fiber morphology.
  • Researchpp 5677-5690Derikvand, M., and Eckelman, C. A. (2015). "Bending moment capacity of L-shaped mitered frame joints constructed of MDF and particleboard," BioRes. 10(3), 5677-5690.AbstractPDF
    The impact of fastener type (glued and unglued butterfly dovetail keys, glued and unglued H-shaped dovetail keys, one-pin dowel, two-pin dowels, and plywood spline) and wood composite material type on the bending moment capacity of L-shaped mitered frame joints under diagonal tension and compression loads was investigated. Specimens were constructed of laminated medium-density fiberboard (LamMDF) and laminated particleboard (LamPB). The glued joint specimens were constructed with polyvinyl acetate (PVAc) adhesive. In both tests, joints reinforced with two dowels had the highest bending moment capacity, whereas unglued joints fastened with H-shaped dovetail keys had the lowest capacity. Splined joints were characterized by the second highest bending moment capacity. Two-pin dowel joints had, on average, 47% greater capacity than one-pin dowel joints. The glued dovetail joints were 31% stronger than the unglued joints. There was no statistically significant difference between the bending moment capacities of butterfly and H-shaped dovetail keys. The LamMDF joints exhibited 7.8% greater capacity than joints constructed of LamPB. Overall, the bending moment capacity of joints loaded in compression was 22% higher than that of joints loaded in tension—when the moment arm in the compression specimens was taken at the inside corner of the joint.
  • Researchpp 5691-5708Wang, M., Wu, W. W., Wang, S. S., Shi, X. Y., Wu, F. A., and Wang, J. (2015). "Preparation and characterization of a solid acid catalyst from macro fungi residue for methyl palmitate production," BioRes. 10(3), 5691-5708.AbstractPDF
    During the process of fungal polysaccharide extraction for health care products and food factories, a large quantity of macro-fungi residues are produced, but most of the residues are abandoned and become environmental pollutants. A solid acid catalyst, prepared by sulfonating carbonized Phellinus igniarius residue, was shown to be an efficient and environmentally benign catalyst for the esterification of palmitate acid (PA) and methanol. As a comparison, two types of common biomass catalysts, wheat straws and wood chips, were prepared. In this study, characterizations, including scanning electron microscopy, thermo-gravimetric analysis, Fourier transform infrared spectrometry, Brunauer-Emmett-Teller assays and elemental analysis, and reaction conditions for the synthesis of methyl palmitate (MP) using solid acid catalysts were investigated. Experiments showed that the solid acid catalyst prepared from P. igniarius residue had a higher catalytic activity than the other two catalysts, and the highest yield of MP catalyzed by P. igniarius residue solid acid catalyst was 91.5% under the following optimum conditions: molar ratio of methanol/PA of 10:1, reaction temperature of 60 °C, mass ratio of catalyst/substrate of 2%, and a reaction time of 1.5 h. Thus, the use of this catalyst offers a method for producing MP.
  • Researchpp 5709-5719Tuhy, L., Samoraj, M., Witkowska, Z., Wilk, R., and Chojnacka, K. (2015). "Using spent mushroom substrate as the base for organic-mineral micronutrient fertilizer - field tests on maize," BioRes. 10(3), 5709-5719.AbstractPDF
    Spent mushroom substrate (SMS) is a noxious byproduct of the mushroom industry. The aim of this work was to convert SMS into organic-mineral micronutrient (Zn(II), Mn(II), and Cu(II)) fertilizer via biosorption and examine the effect of its application in field tests on maize compared to commercial reference micronutrient fertilizer. Crop yield and crop quality were assessed, and multielemental analysis of grains was conducted for the evaluation of the fertilization effect on maize grains and to assess bioavailability of nutrients from fertilizers. Grain yield for maize treated with micronutrients delivered with SMS was noticeably higher (11.5%) than the untreated group and the NPK (nitrogen, phosphorus, potassium) fertilizer treated only group (2.8%). Bioavailability (TF) of micronutrients from SMS were comparable with reference micronutrient fertilizer (7% Zn, 4% Mn, and 2.3% Cu). The new product has the potential to be used as a micronutrient fertilizer. Satisfactory results of grain yield (6.4 Mg ha-1), high content of micronutrients (Zn 1.6%, Mn 1.2%, and Cu 1.8%), and macronutrients (P 1.0%, S 3.1%, Ca 8.2%, and K 0.2%) were observed. The bioavailability suggests that enriched SMS could be a good alternative to fertilizers in the present market.
  • Researchpp 5720-5729Chen, H., Liu, Y., Kong, F., Lucia, L. A., and Feng, X. (2015). "Application of the protoplast fusion technique to engineer a recombinant microorganism to more efficiently degrade chlorophenols," BioRes. 10(3), 5720-5729.AbstractPDF
    Recombinant strain Xz6-1 was constructed by the protoplast fusion technique with the goal of endowing it with the ability to efficiently degrade pentachlorophenol (PCP). This compound was considered as a representative of possible compounds that can be obtained during the bleaching of pulp for papermaking. The potential of Xz6-1and Pseudomonas putida to treat PCP synthetic wastewater was explored. The majority of PCP was removed within the first 20 h; two degradation curves were obtained that followed first-order reaction kinetics. The kinetics data revealed that the rate constant for degradation of PCP for Xz6-1 was 0.063 h-1, a value that was over 50% greater than that of Pseudomonas putida (0.040 h-1). Aerobic granular sludge was highly fortified with Xz6-1 and Pseudomonas putida to provide PCP degradability improvements of 180.9% and 98.3%, respectively, relative to the original sludge. All results demonstrate that the protoplast fusion technique is an effective approach to construct a high-activity chlorophenol-degrading strain.
  • Researchpp 5730-5743Delgado-Aguilar, M., Tarrés, Q., Puig, J., Boufi, S., Blanco, A., and Mutjé, P. (2015). "Enzymatic refining and cellulose nanofiber addition in papermaking processes from recycled and deinked slurries," BioRes. 10(3), 5730-5743.AbstractPDF
    Recycling and deinking processes cause fiber damage because of hornification phenomena and increased external fibrillation. Mechanical refining has been used for many years to enhance the mechanical properties of paper. Biorefining of pulp using enzymes is receiving increasing interest for energy reduction at the refining step of the paper-making process. Moreover, enzymes have also been used for the enhancement of mechanical properties without affecting the drainage rate. As an alternative to mechanical refining treatment, a combination of an enzymatic treatment and cellulose nanofibril (CNF) addition was explored to enhance the mechanical properties of paper. The tests were carried out on a deinked pulp (DIP) suspension made of 50% old newspapers (ONP) and 50% old magazines (OMG). Various enzyme charges and CNF amounts were added to the mixture of ONP and OMG. All pulps (treated and untreated) were characterized from a morphological point of view, and the paper sheets made thereof were mechanically characterized. The combination of the enzymatic treatment with the addition of 3% CNF provided sufficient tensile strength for the paper to be used in high-performance applications.
  • Researchpp 5744-5757Ko, C. H., Leu, S. Y., Chang, C. C., Chang, C. Y., Wang, Y. C., and Wang, Y. N. (2015). "Combining cellulosic ethanol fermentation waste and municipal solid waste-derived fiber with a kraft black liquor-derived binder for recycled paper making," BioRes. 10(3), 5744-5757.AbstractPDF
    Rice straw cellulosic ethanol fermentation waste (CEFW) and municipal solid waste derived fiber (MSWF) were used as alternative fibers for recycled paper making. The fibers were mixed with old newspaper (ONP) fiber at different mass ratios to produce standard recycled papers and paperboards. A “green” adhesive binder derived from kraft black liquor (BLDB) was used to improve the physical properties of the waste-derived paper products. The values of these properties increased linearly with increasing average fiber lengths, regardless of the type of fiber used in the products. BLDB improved the physical properties of the products by 50% for papers and 85% for paperboards, and the performance of this binder was comparable to a commercial urea formaldehyde resin binder. Thermal pressing, however, did not improve the physical properties of the binder-enhanced paper products. With the addition of the adhesive binder, CEFW and MSWF showed reasonable substitution potential for ONP fiber by providing suitable tensile and bursting strength in the recycled paper products. The critical fiber length, which produced the minimum strength properties for the recycled paper products, was approximately 1020 mm.
  • Researchpp 5758-5776Yang, H., Cheng, W., and Han, G. (2015). "Wood modification at high temperature and pressurized steam: A relational model of mechanical properties based on a neural network," BioRes. 10(3), 5758-5776.AbstractPDF
    Thermally modified wood has high dimensional stability and biological durability.But if the process parameters of thermal modification are not appropriate, then there will be a decline in the physical properties of wood.A neural network algorithm was employed in this study to establish the relationship between the process parameters of high-temperature and high-pressure thermal modification and the mechanical properties of the wood. Three important parameters: temperature, relative humidity, and treatment time, were considered as the inputs to the neural network. Back propagation (BP) neural network and radial basis function (RBF) neural network models for prediction were built and compared. The comparison showed that the RBF neural network model had advantages in network structure, convergence speed, and generalization capacity. On this basis, the inverse model, reflecting the relationship between the process parameters and the mechanical properties of wood, was established. Given the desired mechanical properties of the wood, the thermal modification process parameters could be inversely optimized and predicted. The results indicated that the model has good learning ability and generalization capacity. This is of great importance for the theoretical and applicational studies of the thermal modification of wood.
  • Researchpp 5777-5790Li, X., Dang, F., Zhang, Y., Zou, D., and Yuan, H. (2015). "Anaerobic digestion performance and mechanism of ammoniation pretreatment of corn stover," BioRes. 10(3), 5777-5790.AbstractPDF
    The objective of this study was to investigate the anaerobic digestion performance and mechanism of corn stover pretreated with ammonia at three ammonia concentrations (2, 4, and 6%) and four moisture contents (30, 50, 70, and 90%). The physical and chemical structures as well as the changes in its chemical compositions of ammonia-pretreated corn stover were analyzed to understand its biogas production performance. The results showed that ammonia pretreatment could effectively improve the anaerobic digestion performance of corn stover and that the optimal biogas production performance was achieved with 4% ammonia and 70% moisture content. The maximum biogas yield reached 427.1 mL/gVS. The conversion rates of cellulose and hemicellulose were 80.60 and 68.5%, respectively, which is about 30 and 26% higher than those of the untreated corn stover, respectively. The composition and structure analyses showed that ammoniation pretreatment could rupture chemical bonds such as ester and ether bonds in the lignocellulose, partially degrade aliphatic and carbohydrate compounds, and bring anaerobes into sufficient contact with corn stover material, therefore helping to increase biogas yield.
  • Researchpp 5791-5808Giacomozzi, D. E., and Joutsimo, O. (2015). "Drying temperature and hornification of industrial never-dried Pinus radiata pulps. 1. Strength, optical, and water holding properties," BioRes. 10(3), 5791-5808.AbstractPDF
    Hornification and changes in properties of bleached Pinus radiata pulps were studied for oven-dried pulps and compared to never-dried pulps. Evaluation of unrefined and PFI-refined pulps showed an increase in strength loss with high drying temperature. The tensile index was reduced by 40 to 55%, the tear index was reduced by 14 to 31%, and the degree of hornification, measured as WRV, increased from 25 to 34% when the drying temperature was increased from 25 °C to 130 °C. The tensile stiffness index, Scott bond, and elongation were reduced, whereas the bulk, opacity, air permeability, and light scattering values increased at high drying temperatures. Neither fiber deformations nor damages were observed to justify such reductions in strength properties. In PFI refining, pulps dried at 130 °C required three times more revolutions than never-dried pulps to develop tensile index until 70 Nm/g. Dried pulps were found to have less capability to hold water into the fibers’ pore structure, as shown by water retention value. Changes in Scott bond, bulk, and water retention value suggested that besides irreversible pore closure and fibril microfibril aggregation, delamination can contribute to the observed strength loss in dried compared to never-dried pulps.
  • Researchpp 5809-5819Choudhary, M., Sharma, P. C., and Garg, N. (2015). "Crop residue degradation by autochthonous fungi isolated from cropping system management scenarios," BioRes. 10(3), 5809-5819.AbstractPDF
    In the rice-wheat system dominated belt of India (Indo-Gangetic plains; IGP), paddy leaves, about 8 to 9 t/ha of loose and anchored residue in the field, are mechanically harvested. Farmers prefer to burn this residue to clear the field for the timely preparation of conventional wheat sowing. In-situ degradation by autochthonous fungi can be a better option for the disposal of unwanted crop residues. Autochthonous fungi isolated from conservation agriculture-based crop management fields were screened and assessed for their residue degradation potential. Nineteen isolates were selected for detailed enzymatic analysis in submerged fermentation, responsible for lignocellulosic residue degradation. Out of these five fungal isolates RPW 1/3 (Aspergillus flavus), RPW 1/6 (Aspergillus terreus), RPW 1/9 (Aspergillus terreus), RPWM 2/2 (Penicillium janthinellum) and RZWM 3/1 (Aspergillus niger) showed higher activities of cellobiase, CMCase, FPase, xylanase, and laccase enzymes in solid state fermentation. Further two isolates RPW 1/3 and 1/6 showed approximately 30% degradation of straw residue after 10 days incubation.
  • Researchpp 5820-5829Song, J., Yuan, Q., Liu, X., Wang, D., Fu, F., and Yang, W. (2015). "Combination of nitrogen plasma modification and waterborne polyurethane treatment of carbon fiber paper used for electric heating of wood floors," BioRes. 10(3), 5820-5829.AbstractPDF
    The aim of this study was to improve the electrical resistivity, mechanical properties, and interfacial properties between the carbon fiber (CF) and cellulose of conductive paper containing 10% CF so as to better meet the demands for electric heating wood floors. With waterborne polyurethane (WPU) treatment and nitrogen plasma modification methods, the interfacial properties between CF and cellulose were improved dramatically. Fourier transform infrared spectrometry (FTIR) revealed that the plasma modification method reduced the C-H contents and introduced numerous polar groups onto the CF surface. Scanning electron microscopy (SEM) showed that the CF modified by WPU and plasma had good adhesion with cellulose. The tensile index, tensile energy absorption index, and burst index of the paper were enhanced because of the plasma and WPU coating. The carbon fiber and WPU method presented good synergistic action with respect to mechanical properties and electrical resistivity, and the lowest electrical resistivity of conductive paper was reduced from 0.68 omega•cm2 to 0.44 omega•cm2.
  • Researchpp 5830-5844Zhang, M., Zhang, D., Feng, Y., Min, D., and Dai, H. (2015). "The optimization of the water footprint and strength properties of handsheets by the extreme vertices mixture design," BioRes. 10(3), 5830-5844.AbstractPDF
    Water footprint (WF) is widely used as a life cycle assessment (LCA) tool to assess the environmental impacts of water usage associated with forestry-based production. The calculations of WF are significantly influenced by the raw materials and the process. Some information is available on WF in the papermaking industry. However, there has been little consideration of the correlation between the WF and the properties of paper. Technically, the WF and the properties of paper are impacted by the raw materials. Generally, the ideal formula of raw materials used to make paper could decrease the WF while maintaining the properties of the paper. In the current study, the extreme vertices mixture design was used to optimize the WF and properties of the handsheet by the raw materials. The new model indicated that the WF of the handsheet was decreased significantly while the properties was maintained through the adjustment of the raw materials.
  • Researchpp 5845-5862Jablonský, M., Dubinyová, L., Varga, S., Vizárová, K., Šima, J., and Katuščák, S. (2015). "Cellulose fibre identification through color vectors of stained fibre," BioRes. 10(3), 5845-5862.AbstractPDF
    Simple, rapid staining analytical methods with visual color assessment are the most used in practice, but they involve problems including subjective error, low accuracy, qualitative results, and the necessity of using many kinds of stains and a great deal of morphology information for correct identification. A method of objective fiber identification using color vectors of a microscan from stained fibre digital photography is described in this report. A model set of cellulose fibres was prepared: groundwood; sulphate pulp; Whatman paper; and rag fibres. The objective micro-colorimetric method, using RGB (red, green, blue) vectors with discriminatory analysis, reduced the number of stains to 1; requires no morphological information; and the discriminatory power (dp,) of this approach is up to 95 to 100% of correctly identified unknown samples with one color vector R or B. A dp value of 100% was achieved when using 2-P or 3-P combinations of R, G, and B.
  • Researchpp 5863-5875Yang, G., Wang, C., Lyu, G., Lucia, L. A., and Chen, J. (2015). "Catalysis of glucose to 5-hydroxymethylfurfural using Sn-beta zeolites and a Brønsted acid in biphasic systems," BioRes. 10(3), 5863-5875.AbstractPDF
    Selective and efficient dehydration of glucose to 5-hydroxymethylfurfural (HMF) has been a widely explored concept recently, especially from the perspective of employing environmentally benign heterogeneous catalysts. However, there has been a relative paucity of data regarding the application of Sn-Beta zeolites, a category of catalysts that are very innocuous, inexpensive, and effective, toward evaluating bio-based conversions. Sn-Beta was shown to possess good Lewis acidity for catalyzing glucose isomerization to fructose in aqueous media at low pH and accelerating dehydration of glucose to HMF in a biphasic system with high yields. Sn-Beta zeolite with NH4F as the mineralizing agent (Sn-Beta-F) was a more effective catalyst for the selective dehydration of glucose to HMF. An optimal HMF yield of 53.0% was obtained over Sn-Beta-F zeolite in an acidic environment (pH 1) after 70 min at 190 °C. The reaction system was also effective for conversion of cellulose to HMF with a yield of 32.2% preliminarily.
  • Researchpp 5876-5889Cellatoğlu, N., and İlkan, M. (2015). "Torrefaction of solid olive mill residue," BioRes. 10(3), 5876-5889.AbstractPDF
    Solid olive mill residue (SOMR), a lignocellulosic material obtained from olive oil extraction, is a potential attractive source of biomass for energy generation. Although SOMR can be directly combusted, a pretreatment can reduce the oxygen and moisture contents of raw SOMR for efficient energy generation. Torrefaction is a promising thermal pretreatment method for improving fuel characteristics of raw SOMR. In this study, torrefaction characteristics of SOMR were investigated at three different torrefaction temperatures and holding times. Ultimate and proximate analysis results of torrefied SOMR were compared with dried SOMR. Results indicate that an increased torrefaction temperature and holding time can lead to a more qualified solid fuel with higher carbon content, increased higher heating value (HHV), and reduced oxygen content. Further, increased HHV and removal of volatiles are indicators of more energy-dense solid fuel obtained from SOMR. Experimental results revealed that moderately severe torrefaction conditions with holding times not exceeding 30 minutes are suitable for torrefaction of SOMR.
  • Researchpp 5890-5905Boakye-Boaten, N. A., Xiu, S., Shahbazi, A., and Fabish, J. (2015). "Liquid hot water pretreatment of Miscanthus x giganteus for the sustainable production of bioethanol," BioRes. 10(3), 5890-5905.AbstractPDF
    The production of ethanol from lignocellulosic biomass provides an alternative to fossil fuels. In this study, liquid hot water (LHW)-pretreated Miscanthus x giganteus (MxG) was used to produce bioethanol through simultaneous saccharification and fermentation (SSF). MxG was pretreated at temperatures between 170 and 200 °C, for 5 to 15 min. The pretreatment was able to remove between 68.3% and 77.0% of the lignin present in the biomass. The highest percentage yields of sugars from pretreated MxG after enzymatic saccharification (32 °C, pH 4.5, 48 h), by a cocktail of two enzymes were 44.0% glucose and 42.0% xylose of theoretical. Ethanol concentrations between 0.780 and 3.715 g/L, and a high ethanol yield of 71.8% of theoretical were obtained using Saccharomyces cerevisiae (ATCC 24858) for fermentation. A comparison of scanning electron micrographs of the pretreated biomass showed morphological changes that enhanced the release of glucose and bioethanol yield.
  • Researchpp 5906-5919Su, W., Chen, C., Zhu, Y., Yang, W., and Dai, H. (2015). "Fouling characteristics of dissolved organic matter in papermaking process water on polyethersulfone ultrafiltration membranes," BioRes. 10(3), 5906-5919.AbstractPDF
    In the papermaking industry, closure of process water (whitewater) circuits has been used to reduce fresh water consumption. Membrane separation technology has potential for use in treating process water for recirculation. The purpose of this study was to reveal the fouling characteristics of a polyethersulfone (PES) ultrafiltration membrane caused by dissolved organic matter (DOM) in process water. Ultrafiltration membranes (UF) and DAX ion exchange resins were applied to characterize the molecular weight (MW) and hydrophilicity distribution of DOM. The interactions between various fractions of DOM and a PES ultrafiltration membrane were investigated. The membrane fouling characteristics were elucidated by examining the filtration resistances and linearized Herman’s blocking models. The results demonstrated that the membrane was fouled significantly by much of the MW distribution. The membrane was fouled more significantly by the low MW fraction rather than the high MW fraction. The filtration resistances and the fitted equation of Hermia’s laws indicated that hydrophilic organics were the main foulants. The hydrophilic organics partially block the membrane pores and form intermediate blocking, reducing the effective filtration area, while the hydrophobic organics form a gel layer or cake on the surface of the membrane.
  • Researchpp 5920-5931Anjos, O., García-Gonzalo, E., Santos, A. J. A., Simões, R., Martínez-Torres, J., Pereira, H., and García-Nieto, P. J. (2015). "Using apparent density of paper from hardwood kraft pulps to predict sheet properties, based on unsupervised classification and multivariable regression techniques," BioRes. 10(3), 5920-5931.AbstractPDF
    Paper properties determine the product application potential and depend on the raw material, pulping conditions, and pulp refining. The aim of this study was to construct mathematical models that predict quantitative relations between the paper density and various mechanical and optical properties of the paper. A dataset of properties of paper handsheets produced with pulps of Acacia dealbata, Acacia melanoxylon, and Eucalyptus globulus beaten at 500, 2500, and 4500 revolutions was used. Unsupervised classification techniques were combined to assess the need to perform separated prediction models for each species, and multivariable regression techniques were used to establish such prediction models. It was possible to develop models with a high goodness of fit using paper density as the independent variable (or predictor) for all variables except tear index and zero-span tensile strength, both dry and wet.
  • Researchpp 5932-5948Fertah, M., Belfkira, A., Taourirte, M., and Brouillette, F. (2015). "Controlled release of diclofenac by a new system based on a cellulosic substrate and calcium alginate," BioRes. 10(3), 5932-5948.AbstractPDF
    Promising controlled release systems were prepared from renewable natural products. Paper, used as the system core, was made with commercial kraft pulp and with bleached lignocellulosic pulps extracted from local plants. The characteristics of those pulps (fines content and fiber length) as well as paper thickness, porosity, and roughness, were evaluated. Alginate served as the protective membrane. The releasability of Diclofenac as a function of time and pH was studied under constant temperature (37 °C) and constant stirring (200 rpm). Also the influence of the type of paper and the calcium alginate concentration in the protective layer were highlighted. The extent of release reached 80% in a basic medium in a variable time interval 7 to 16 h, whereas in an acid medium it did not exceed 24% in 33 h. Diffusion, Fickian diffusion, and diffusion-erosion were judged to be important contributing mechanisms based on the Korsmeyer-Peppas kinetic model for those various matrixes. Different formulations were found to have significant controlled release properties that could be used in the prolonged release of the active ingredients. Because of the low release in acidic medium, the formulated system could be a good candidate to protect the active ingredient from acidic medium.
  • Researchpp 5949-5960Cao, J. H., and Zhao, J. R. (2015). "Fenton depolymerization of cellulosic biomass in modified cuprammonium solution," BioRes. 10(3), 5949-5960.AbstractPDF
    This preliminary study developed a novel cellulose pretreatment method for cost-effective cellulosic utilization using a modified cuprammonium solution as a solvent to dissolve cellulose followed by molecular oxygen/Fenton depolymerization. The modified cuprammonium solution is composed of cuprammonium solution and a special catalyst that could efficiently enhance cellulosic oxygen sensitivity and therefore improve cellulosic depolymerization. The molecular oxygen depolymerization and Fenton depolymerization of cellulosic biomass dissolved in the modified cuprammonium solution were investigated. The results demonstrate that the Fenton reaction efficiently depolymerized the cellulose dissolved in the modified cuprammonium solution and reached the monomers with no loss of organic carbon, and almost all the cellulose maintained solubility without reagglomeration after cuprammonium was removed. Molecular oxygen oxidation reduced the cellulose average degree of polymerization (DP) to approximately 4 with less cost, and the oxygen pre-oxidation increased the H2O2 utilization in the Fenton depolymerization and remarkably reduced the H2O2 requirement.
  • Researchpp 5961-5973Luo, H., Lu, J., Ren, S., Fang, G., and Jiang, G. (2015). "Studies of polyvinyl alcohol/alkali lignin/silica composite foam material (PLCFM)," BioRes. 10(3), 5961-5973.AbstractPDF
    This study investigates methods for improving the heat resistance of polyvinyl alcohol/alkali lignin foam material (PLFM). Tetraethoxysilane (TEOS) was used as a precursor to prepare PLCFM by a sol-gel method. The PLCFM, prepared with different levels of TEOS, was characterized by Fourier Transform Infrared spectrometry (FTIR), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). The results indicated that the addition of silica notably improved the heat resistance properties and the initial decomposition temperature of the foam and exhibited good biocompatibility with the polyvinyl alcohol (PVOH) and alkali lignin. The melting temperature of the PLCFM also increased significantly. It reached 268 °C when the silica content was 10%, which was 110 °C higher than that of PLFM. The mechanical properties were also improved to 27.42 MPa.
  • Researchpp 5974-5986Abd Hamid, S. B., Teh, S. J., and Lim, Y. S. (2015). "Catalytic hydrothermal upgrading of alpha-cellulose using iron salts as a Lewis acid," BioRes. 10(3), 5974-5986.AbstractPDF
    The catalytic hydrothermal carbonization (C-HTC) method is proposed as a way to convert renewable feedstocks into carbon nanomaterial, using α-cellulose as the model compound. In this study, cellulose reacted with a controlled amount of Lewis acid catalyst (FeCl2 and FeCl3) under hydrothermal conditions, at temperatures ranging from 180 to 220 °C, for 6 to 24 h. The Lewis acid catalyst’s effect on the formation of carbon nanomaterials in the C-HTC reaction was investigated. This study showed that Lewis acid catalysts promoted the complete carbonization of cellulose at a reduced temperature of 200 °C. The addition of FeCl2 in C-HTC also promoted greater C=O functionality compared to FeCl3. Furthermore, the surface area of the carbon nanomaterials derived from the hydrothermal carbonization of cellulose increased from 7.92 to 15.87 and 12.96 m2 g-1 for the uncatalysed, FeCl2 and FeCl3-catalysed HTC, respectively. The findings in this study shed light on the effect of Lewis acid properties on the tunability of functional groups in the preparation of carbonaceous materials for high-end applications.
  • Researchpp 5987-5993Zhu, R., Zhang, Y., and Yu, W. (2015). "Changes in the chemical properties of Phyllostachys iridescens bamboo with steam treatment," BioRes. 10(3), 5987-5993.AbstractPDF
    This study explored the chemical properties of heat-treated bamboo. Oriented bamboo fiber mats (OBFMs) of Phyllostachys iridescens bamboo, as units of a bamboo fiber-reinforced composite (BFRC), were heat-treated in saturated steam at 0.40 MPa (150 °C) for 110, 140, or 170 min. After heat treatment, the color of oriented bamboo fiber mats changed noticeably. The chemical properties of the bamboo were examined. The results revealed that the contents of holocellulose and hemicelluloses decreased, while the contents of α-cellulose and water extractives and buffering capacity increased. The pH value decreased compared with control samples. The change in the chemical properties of the OBFMs would have an effect on the properties of the BFRC.
  • Researchpp 5994-6000Li, Y., Li, X., Huang, Q., Wu, Y., Li, X., and Chen, Z. (2015). "Impregnation with microcrystalline wax to improve rosewood dimensional stability and surface hardness," BioRes. 10(3), 5994-6000.AbstractPDF
    Air-dried rosewood (Aniba rosaeodora) samples with sizes of 50 mm (length) by 50 mm (width) by 20 mm (thickness) were pretreated with NaOH to increase their permeability. The specimens were then impregnated with microcrystalline wax at a temperature of 100 °C to obtain various weight gains at four treatment durations. After impregnation, the swelling and shrinkage extents and surface hardness of the rosewood were measured. The results showed that, compared with untreated specimens, the linear swelling extent, volumetric swelling extent, and linear shrinkage extent of the impregnated specimens decreased by 75.23%, 59.85%, and 80.70%, respectively, and the surface hardness of the treated specimens increased by 43.36%. The impregnation with wax significantly increased the dimensional stability and surface hardness of the rosewood.
  • Researchpp 6001-6013Li, Z., Yang, R., Yang, F., Zhang, M., and Wang, B. (2015). "ZnO deposit on O-ZrP as paper filler and its potential antibacterial property," BioRes. 10(3), 6001-6013.AbstractPDF
    ZnO nanoparticles (NPs) were reduced by treatment with chitosan oligosaccharide (COS) and loaded on organic zirconium phosphate (OZrP) by electrostatic self-assembly in an aqueous medium. The size and morphology of the ZnO NPs was modified using OZrP, which was applied to disperse the ZnO NPs and act as a stabilizer. The synthesized nanocomposites (NC) were used as fillers, and the surface coating method was applied to prepare cellulose-based composite papers having antibacterial properties. The composites were characterized using UV/vis spectroscopy, transmission electron microscopy (TEM), energy dispersion X-ray (EDX) spectrometry, X-ray diffraction (XRD), zeta potential measurements, and scanning electron microscope (SEM). Results indicated that the average diameter of ZnO NPs was less than 50 nm. ZnO NPs was dispersed on the surface and in the interlayer of the OZrP. The physical properties of the finished papers were improved by coating with ZnO/COS/OZrP (ZCO) NCs. Paper that was coated with ZCO yielded good antibacterial properties.
  • Researchpp 6014-6031Dettmer, J., and Smith, G. D. (2015). "Comparing properties of North American manufactured particleboard and medium density fiberboard - Part I: Particleboard," BioRes. 10(3), 6014-6031.AbstractPDF
    The goal of this study was to collect up-to-date data on the properties of Canadian and United States-manufactured particleboard (PB) and medium density fiberboard (MDF). Sixty-three manufacturers were contacted and asked to participate in a mechanical and physical properties comparison study. This is the first of two papers presenting the results of the PB evaluation. Samples from five different manufacturing facilities from Canada and the United States were evaluated. Each manufacturing facility provided 5 full-sized, (2440 x 1220 mm) M2-grade panels. These were tested according to North American standards. The performed tests included internal bond (IB), bending and elastic moduli (MOR/MOE), thickness swelling (TS), linear expansion (LE), vertical density profile (VDP), and face and edge screw withdrawal resistance (SWR). Four out of 5 press lines exceeded the American National Standards Institute (ANSI) A208.1 (2009) recommendation for IB. Only one of the tested particleboard sets reached the recommended ANSI standard for MOR. Results for the edge SWR showed that none of the tested particleboard manufacturers reached the ANSI recommended value.
  • Researchpp 6032-6043Dettmer, J., and Smith, G. D. (2015). "Comparing properties of North American manufactured particleboard and medium density fiberboard - Part II: Medium density fiberboard," BioRes. 10(3), 6032-6043.AbstractPDF
    The properties of medium density fiberboard (MDF) derived from different manufacturing plants were compared. Each plant provided 5 full-sized (2440 by 1220 mm) 155-grade panels that were tested according to ANSI A208.2-2009. None of the panels met the recommended value for Internal Bond (IB). Mean values for Thickness Swell (TS) were all significantly different, with one manufacturer below the standard. Three manufacturers exceeded the recommended face Screw Withdrawal Resistance (fSWR) values, one was equal to it, and one failed. Three manufacturers exceeded the edge SWR (eSWR) standard, and the remaining two fell below. Two manufacturers met the standard for Modulus of Rupture (MOR), and only one manufacturer failed to meet the Modulus of Elasticity (MOE) requirements. Linear Expansion (LE) was evaluated for a RH change from 50 to 90%. The panels made with pMDI-resin consistently had some of the highest mean values for MOR, MOE, fSWR, and IB and exhibited good performance in the TS test.
  • Researchpp 6044-6054Santis-Espinosa, L. F., Perez-Sariñana, B. Y., Guerrero-Fajardo, C. A., Saldaña-Trinidad, S., Lopéz-Vidaña, E. C., and Sebastian, P. J. (2015). "Drying mango (Mangifera indica L.) with solar energy as a pretreatment for bioethanol production," BioRes. 10(3), 6044-6054.AbstractPDF
    The drying kinetics of mango were examined as a first step of pretreatment for biofuels production. This method exploits the potential of the carbohydrate present in the raw material, where the concentration for fermentation was adjusted to 20 g/L of reducing sugars. Dehydration was carried out by natural convection using a solar dryer. The solar dryer employed was made of transparent acrylic, and it had an internal volume of 0.125 m3. The dehydration was performed through natural convection. The dehydration achieved 95.6% moisture removal in 28 h and reached maximum temperatures of 52 °C and 56 °C, corresponding to first and second phases, respectively. The minimum temperature reached was 21 °C. The rate of drying was evaluated during the first stage, between 0 to 4 hours, with radiation maxima of 991 and 1014 W/m2 for that day. At the peak of radiation the drying rate was 0.060 g H2O/ g dry mass/ min.
  • Reviewpp 6055-6080Gómez-de la Cruz, F. J., Casanova-Peláez, P. J., López-García, R., and Cruz-Peragón, F. (2015). "Review of the drying kinetics of olive oil mill wastes: Biomass recovery," BioRes. 10(3), 6055-6080.AbstractPDF
    The drying kinetics of olive oil mill wastes was analyzed based on experiments carried out by various researchers utilizing different drying systems. A critical review of the literature was done, and mathematical models of drying curves proposed by investigators were evaluated. A comparison between the best mathematical models of fit in the drying curves used in past experiments and a two-term Gaussian model was performed. This model improved all the results of fit in each experiment. Drying rates and drying stages were obtained and discussed. An average drying rate for each experiment from the two-term Gaussian model was calculated. This value allowed for visualizing and comparing the average speed of evaporated water in each experiment for the different dryers. Finally, and after having verified that almost all drying occurs mainly by a diffusion phenomenon, an analysis on the effective moisture diffusivity and activation energy values was performed. The results indicated that there was no dependency of these quantities on independent variables such as the drying air temperature, the drying air velocity, and the sample thickness. It follows that drying of olive oil mill wastes is a very complex physical process that depends heavily on aspects such as pieces of pit, pulp, skin, vegetation water, olive oil content, sugars and organics compounds of different nature.
  • Reviewpp 6081-6094Yang, F., Jin, E. S., Zhu, Y., Wu, S., Zhu, W., Jin, Y., and Song, J. (2015). "A Mini-review on the applications of cellulose-binding domains in lignocellulosic material utilizations," BioRes. 10(3), 6081-6094AbstractPDF
    This manuscript provides a mini review on the fundamentals of cellulose binding domains (CBDs) or cellulose binding modules (CBMs) and their applications using lignocellulosic materials. CBDs, the non-productive part of cellulases, have miscellaneous biological functions and have been widely applied in lignocellulose hydrolysis, protein engineering, structural support, metabolism, energy storage, antibiosis, immunological recognition, targeting, attachment, etc. due to their specific affinity to various substrates of lignocelluloses. Understanding of the properties and mechanisms of CBDs is of vital significance because it provides the basis for fine manipulation of cellulose-CBM interactions and eventually improves the bioconversion performance of lignocelluloses into fuels and desired chemicals. In this short review, the fundamentals of CBD, the definition of CBM family, and the structures of different CBM families are introduced. Then recent findings in the applications of CBDs are discussed relative to the lignocelllulosic utilizations.
  • Reviewpp 6095-6206Hubbe, M. A., Rojas, O. J., and Lucia, L. A. (2015). "Green modification of surface characteristics of cellulosic materials at the molecular or nano scale: A review," BioRes. 10(3), 6095-6206.AbstractPDF
    Many current and potential uses of cellulosic materials depend critically on the character of their surfaces. This review of the scientific literature considers both well-established and emerging strategies to change the outermost surfaces of cellulosic fibers or films not only in terms of chemical composition, but also in terms of outcomes such as wettability, friction, and adhesion. A key goal of surface modification has been to improve the performance of cellulosic fibers in the manufacture of composites through chemistries such as esterification that are enabled by the high density of hydroxyl groups at typical cellulosic surfaces. A wide variety of grafting methods, some developed recently, can be used with plant-derived fibers. The costs and environmental consequences of such treatments must be carefully weighed against the potential to achieve similar performances by approaches that use more sustainable methods and materials and involve less energy and processing steps. There is potential to change the practical performances of many cellulosic materials by heating, by enzymatic treatments, by use of surface-active agents, or by adsorption of polyelectrolytes. The lignin, hemicelluloses, and extractives naturally present in plant-based materials also can be expected to play critical roles in emerging strategies to modify the surfaces characteristics of cellulosic fibers with a minimum of adverse environmental impacts.
  • Reviewpp 6207-6229Pereira, H. (2015). "The rationale behind cork properties: A review of structure and chemistry," BioRes. 10(3), 6207-6229.AbstractPDF
    Cork is a natural cellular material of biological origin with a combination of properties that make it suited for worldwide use as a wine sealant and insulation material. Cork has low density, is buoyant, is not very permeable to fluids, has a low thermal coefficient, exhibits elasticity and deformation without fracturing under compression, and has considerable durability. Such characteristics result from the features of its cellular structure, primarily its cell dimensions and topology, and from the chemical composition of the cell wall. The characteristics of the two main chemical components (suberin and lignin, which represent 53% and 26%, respectively, of the cell wall) have been analyzed. The limits of natural variation and their impacts on cork properties are discussed and used to define the material as “cork”.
  • Reviewpp 6230-6261Reza, M., Kontturi, E., Jääskeläinen, A. S., Vuorinen, T., and Ruokolainen, J. (2015). "Transmission electron microscopy for wood and fiber analysis - A Review," BioRes. 10(3), 6230-6261.AbstractPDF
    This review describes use of transmission electron microscopy (TEM) in wood and fiber analysis. Analytical techniques and sample preparation methods are used to localize substructures of the cell wall polymers and are discussed in this review. The ultrastructural features of the wood cell walls, the structures formed by microfibrils, and the distribution of cell wall polymers, as revealed by TEM, are covered. Research investigating the distribution of lignin in tension and compression woods using TEM is reviewed. Different kinds of wood biodegrading enzymes localized using TEM are mentioned. Additional features of TEM, i.e., 3D imaging, analytical TEM, and electron diffraction are discussed. Lastly, a comparison between TEM and other imaging techniques used for wood and fiber research are made. Thus, this review provides insight into the contribution of TEM in wood research since its invention and demonstrates how to use it more effectively in the future.
  • Reviewpp 6262-6284Nasir, M., Hashim, R., Sulaiman, O., Nordin, N. A., Lamaming, J., and Asim, M. (2015). "Laccase, an emerging tool to fabricate green composites: A review," BioRes. 10(3), 6262-6284.AbstractPDF
    In the last two decades, laccases have received much attention from researchers because of their specific ability to oxidize lignin. This function of laccase is very useful for applications in several biotechnological processes, including delignification in the pulp and paper industry and the detoxification of industrial effluents from the textile and petrochemical industries. This review focuses on laccase-mediated fiberboard synthesis. Growing concerns regarding the emission of formaldehyde from wood composites has prompted industrialists to consider the fabrication of green composites. Laccase-mediated fiber treatments oxidize the lignin component without affecting the cellulose structure. As a result, free radicals are generated on the fiber surface, and these can act as potential reactive sites for further cross-linking reactions in board manufacturing. Binderless fiberboards prepared using such methods can be considered as green composites because the manufacturing process involves no additional resin.
  • Reviewpp 6285-6304Xu, J., Li, M., and Ni, T. (2015). "Feedstock for bioethanol production from a technological paradigm perspective," BioRes. 10(3), 6285-6304.AbstractPDF
    Because of the impending energy crisis and the environmental problems caused by the excessive use of fossil fuels, biofuels produced from renewable energy biomass have been playing a more significant role in the world. This follows from their obvious environmental and economic advantages. Bioethanol, the most widely used transportation biofuel, is typically derived from plant-based feedstock sources such wheat, sugar beet, corn, straw, and wood. However, the main problem with bioethanol production is that despite the range of feedstock, raw material availability varies considerably from season to season, as there is no systematic framework. By combining technological paradigm theory with literature mining, we found that bioethanol feedstock production development has followed a three-stage trajectory, which is in accordance with the traditional technological paradigm – the S-curve. This new curve can be divided into BFDP (bioethanol feedstock development paradigm) competition, BFDP diffusion, and BFDP shift. Each phase has a different generation of feedstock; first-generation bioethanol in BFDP competition, second-generation bioethanol in BFDP diffusion, and third-generation bioethanol in BFDP shift. Further, based on the technological support, literature mining, and a realistic background, the second-generation bioethanol (mainly lignocellulosic biomass) is expected to continue to be a significant future trend in the world. The new BFDP framework presented in this paper may provide scholars with research ideas for the future.