NC State
BioResources
  • Editorialpp 2182-2183Laleicke, P. (2018). "Wood waste, the challenges of communication and innovation," BioRes. 13(2), 2182-2183.AbstractArticlePDF

    Wood is our material of choice for sustainable and environmental friendly construction and manufacturing of products. Wood has excellent properties for reuse, realized and implemented through a cascading utilization, introducing intermittent product lives. In contrast, wood waste is still a heavily under-valued resource in North America. With current practices of sourcing virgin wood at lowest cost and few efforts to shift wood out of the single-use convenience mode of utilization, true innovation is unlikely to occur. Technical problems have been assessed and solved. What remains is collecting and combining unintelligently scattered and hidden information about wood utilization into a single place. And, if connecting a complimentary feedstock supply to our current industries remains a challenge, then innovation must happen on the product-side too.

  • Editorialpp 2184-2186Chen, Z., Zhang, L., and He, Z. (2018). "Rethinking the determination of wet strength of paper," BioRes. 13(2), 2184-2186.AbstractArticlePDF

    The wet strength of paper is an important physical property, especially for household paper, e.g., paper towels, as well as for some functional paper grades. However, in the literature, various conditions of immersing the samples in water before testing have been reported, resulting in differences in their extent of saturation and inconsistency in the testing results. Also, the dryness of paper specimens before the wet-strength testing is a critical parameter for the wet strength of paper; however, this aspect has been neglected in the literature. In this editorial, the methods of examination for both the temporary and permanent wet strength are discussed. A more reasonable method is proposed, such that the wet strength is reported according to the immersion time and the initial dryness of the paper. As an option, the results may be expressed as a function of immersion time and initial dryness. In this way, the trend of temporary wet strength related to the immersion time in water can be expressed clearly and the permanent wet strength also can be evaluated comprehensively.

  • Researchpp 2187-2203Alves de Oliveira, R., Komesu, A., Vaz Rossell, C. E., Wolf Maciel, M. R., and Maciel Filho, R. (2018). "Evaluation of hybrid short path evaporation to concentrate lactic acid and sugars from fermentation," BioRes. 13(2), 2187-2203.AbstractArticlePDF

    Lactic acid is an important organic compound that finds various applications in the chemical, pharmaceutical, food, and medical industries. Many of these applications require lactic acid with high purity. Hybrid short path evaporation (HSPE) is a separation process well studied in the petrochemical sector that is mainly used to obtain compounds with high purity. It is also a process offering small residence time, low pressure, and environmentally friendliness. The concentration process of lactic acid was studied by using HSPE in the presence of high total reducing sugar content remaining from sugarcane molasses fermentation. In this work, the influence of operational conditions, such as evaporator temperature (86.4 °C to 153.6 °C), internal condenser temperature (7.95 °C to 18 °C), and feed flow rate (8.27 to 21.7 mL/min), on lactic acid concentration and mass percentages were evaluated. The results showed that all variables influenced the process. Mathematical models were developed for the mass percentage and concentration of the total reducing sugar in the distilled stream and for the mass percentage at residue stream. Under the best operational conditions, the concentration of lactic acid (≈ 247.7 g/L) was 2.5 times higher than the initial fermentation broth (≈ 100.1 g/L).

  • Researchpp 2204-2217Feng, Y., Zhong, H., Liang, Y., Lei, B., Chen, H., Yin, X., and Yu, X. (2018). "Structure and compositional changes of eucalyptus fiber after various cycles of continuous screw extrusion steam explosion," BioRes. 13(2), 2204-2217.AbstractArticlePDF

    A continuous screw extrusion steam explosion (SESE) pretreatment method was used to disrupt the structure of eucalyptus fiber. The effects of increasing numbers of SESE pretreatment cycles on the structure and composition of eucalyptus fiber were investigated. Lignin was isolated from the eucalyptus fiber via the phosphoric acid method under modest reaction conditions (50 °C), and was characterized. The SESE pretreatment led to a decrease in crystallinity and degraded the hemicellulose and cellulose. The surface of the eucalyptus fiber was damaged by SESE pretreatment, and significant surface debris were observed. The isolated lignin was typical of guaiacyl-syringyl (G-S)-enriched lignin of eucalyptus hardwood. The SESE pretreatment led to the cleavage of ether linkages and condensation of lignin, and thus a more heterogeneous structure compared with that of raw lignin. The increased molecular weight of SESE-pretreated lignin showed that condensation was more pronounced with increased numbers of SESE cycles. The thermostability of lignin increased after three SESE cycles and remained stable with further cycles. This corresponded to the trend in the molecular weight of lignin with increased SESE pretreatment. The SESE pretreatment was more efficient for pretreating eucalyptus fiber than conventional batch-type steam explosion, and thus is more suitable for industrial application.

  • Researchpp 2218-2232Lai, Z., Li, S., Zhang, Y., Li, Y., and Mu, J. (2018). "Influence of urea formaldehyde resin on the pyrolysis of biomass components: Cellulose, hemicellulose, and lignin," BioRes. 13(2), 2218-2232.AbstractArticlePDF

    Wood-based panels, which are often used and then abandoned, are a potential resource for energy recovery. To better understand the pyrolysis of wood-based panels, the effect of urea formaldehyde (UF) resin on the pyrolysis of the wood components (cellulose, hemicellulose, and lignin) was investigated. Thermogravimetric analysis (TGA), gas chromatography coupled with mass spectrometry (GC-MS), and an ultimate analysis were used to investigate the pyrolysis process and products of the biomass components mixed with 10% UF resin. The UF resin specifically inhibited the decomposition rate of cellulose and promoted the thermal decomposition of lignin. For xylan, the UF resin had little impact. The UF resin mainly affected the mass loss of C and O. Loss of both elements in lignin was promoted, but only C loss increased in cellulose. The nitric gases generated from the pyrolysis mixtures were HCN and NH3, and N from the UF resin tended to transform into NH3. Influence of the UF resin on the pyrolysis liquids was mainly seen on the N compounds. With the addition of the UF resin, more nitrogenous compounds were detected in the pyrolysis liquids. The relative contents of nitrogenous compounds in the pyrolysis liquids from cellulose and lignin were 12.8% and 64.3%, respectively.

  • Researchpp 2233-2246Lan, H., Zhang, H., Yang, D., Bi, S., Liu, J., Wang, W., and Zhang, H. (2018). "Screening predominant bacteria and construction of efficient microflora for treatment of papermaking white water," BioRes. 13(2), 2233-2246.AbstractArticlePDF

    Three strains of bacteria were isolated and purified from activated sludge for white water treatment in the laboratory. These strains were identified as Bacillus subtilis, Bacillus cereus, and Virgibacillus pantothenticus through a morphological analysis, the MIDI Sherlock automatic microbial identification system, and 16S rRNA methods. The results of the construction of efficient microflora for white water showed that a mass percentage ratio of B. subtilis, B. cereus, and V. pantothenticus of 50%:35%:15% achieved an optimal treatment effect. Analysis by gas chromatograph-mass spectrometer (GC-MS) established that the content of characteristic pollutants in white water decreased notably after treatment with the efficient microflora, and detected the intermediate products of short chain fatty acids, alcohols, and other compounds. Moreover, through measuring the removal rate of chemical oxygen demand (COD), electrical conductivity, and cationic demand (CD), the optimal retention time for white water treatment with the efficient microflora was 4 h to 6 h, and when the removal rate of COD reached approximately 90%, the electrical conductivity and the cationic demand were reduced to lower values.

  • Researchpp 2247-2267Tanase, C., Domokos, E., Coșarcă, S., Miklos, A., Imre, S., Domokos, J., and Dehelean, C. A. (2018). "Study of the ultrasound-assisted extraction of polyphenols from beech (Fagus sylvatica L.) bark," BioRes. 13(2), 2247-2267.AbstractArticlePDF

    The aim of this study was to reach the best efficiency of total polyphenols extraction from beech bark. The impacts of solvent concentration, sonication time, and temperature were investigated relative to the yield of extractives from beech (Fagus sylvatica L.) bark using ultrasound-assisted extraction at 40 kHz ultrasonic frequency. All extracts were characterized quantitatively in terms of total content in polyphenols. The extracts obtained in the optimized conditions were also evaluated qualitatively. Beech bark can be a rich raw material for obtaining bioactive polyphenols. An experimental planning method was described that optimized the process and increased the extraction yield. In the experiments, water and ethanol:water solvent solutions were used. The efficiency of the extraction process was determined based on a factorial analysis of variance. The maximum extraction yield of total polyphenols (72.716 mg gallic acid equivalents/g beech bark) was obtained using a processing time of 20 min, an extraction temperature of 65 °C, and an ethanol solvent concentration of 70%. The extracts obtained under the optimum conditions were characterized to determine potential uses of beech bark extractives. The results obtained indicated that ultrasound-assisted extraction was an efficient method for the extraction of natural compounds from beech bark; thus, this method allows for the full utilization of this abundant and low-cost industrial waste.

  • Reviewpp to be addedSu, Y., Yang, B., Liu, J., Sun, B., Cao, C., Zou, X., Lutes, R., and He, Z. (2018). "Prospects for replacement of some plastics in packaging with lignocellulose materials: A brief review," BioRes. 13(2), Page numbers to be added.AbstractArticlePDF

    There has been increasing concern regarding environmental problems arising from the widespread use of petroleum-based plastic materials for packaging. Many efforts have been made to develop sustainable and biodegradable packaging materials to replace plastic products. The current review summarizes recent research progress in developing cellulose packaging materials to replace plastics used for cushioning and barrier packaging functions based on pulp fibers, cellulose nanofibers, and regenerated cellulose films to benefit from their renewability, sustainability and biodegradability. The cushioning packaging materials include molded pulp products and bio-based foams. Advanced cellulose films and paper can be good barriers for oxygen and carbon dioxide gases, as well as for water vapor. Several cellulose fiber-based packaging products have been commercialized in areas that used to be occupied solely by plastic products.

  • Researchpp 2268-2282Cruz, N., Bustos, C., Aguayo, M. G., Cloutier, A., and Castillo, R. (2018). "Impact of the chemical composition of Pinus radiata wood on its physical and mechanical properties following thermo-hygromechanical densification," BioRes. 13(2), 2268-2282.AbstractArticlePDF

    The thermo-hygromechanical densification process changes the chemical composition and the physical and mechanical properties of wood. The aim of this work was to study the impact of the chemical composition of Pinus radiata wood on its physical and mechanical properties following the thermo-hygromechanical densification process. The samples were initially segregated by lignin content. Density, hardness, modulus of elasticity (MOE), and modulus of rupture (MOR), in addition to lignin, α-cellulose, hemicellulose, and extractive contents, were determined before and after the densification process. The results indicated that densified wood with high initial lignin content had greater rate of increases in density and MOE than wood with lower initial lignin content. Additionally, densified wood with lower initial lignin content had greater rate of increases in hardness. The rate of increase of MOR did not show significant differences within both groups. Carbohydrates present in the control and the densified wood played an important role in the mechanical strength of the final product.

  • Researchpp 2283-2292Jiang, W., Tomppo, L., Pakarinen, T., Sirviö, J., Liimatainen, H., and Haapala, A. (2018). "Effect of cellulose nanofibrils on the bond strength of polyvinyl acetate and starch adhesives for wood," BioRes. 13(2), 2283-2292.AbstractArticlePDF

    Nanocellulose is a competitive reinforcement material for use in biocomposite structures and fibrous products. In this study, adhesive mixtures of dicarboxylic acid cellulose nanofibrils (CNF) were dispersed into commercial polyvinyl acetate (PVAc) and starch adhesives, which were applied to Norway spruce (Picea abies) to assess their performance in wood joining. Single-lap joints were prepared and tested with PVAc mixtures with 0 to 0.64 wt% CNF and starch glue mixtures containing 0 to 1.07 wt% CNF. CNF suspensions having three concentrations (0.64, 0.96, and 1.28%) were compared. The results showed that the optimum amount of CNF, 0.48% suspensions, added to PVAc increased the average lap joint strength (EN 205:2003) by 74.5% when compared to control specimens with pure PVAc. Correspondingly, 0.96% CNF suspensions also enhanced the strength of starch adhesive by 34.5%. Lower and higher CNF concentrations showed clearly inferior performance.

  • Researchpp 2293-2303Liu, X., Zu, X., Liu, Y., Sun, L., Yi, G., Lin, W., and Wu, J. (2018). "Conversion of waste water hyacinth into high-value chemicals by iron (III) chloride under mild conditions," BioRes. 13(2), 2293-2303.AbstractArticlePDF

    This study examined a novel approach for converting waste water hyacinths into high-value chemicals under low temperature and low atmospheric pressure by using iron (III) chloride (FeCl3), an oxidant that has the unique properties of nontoxicity, low-cost, and abundance. The conversion process and transformation products of water hyacinths under different conditions were investigated and characterized. The results showed that the content of lignocellulose gradually decreased in the reaction solution. The chemical structure of lignocellulose in the water hyacinths was changed, and the glycosidic bonds of the water hyacinths were cleaved. The surface structure and crystalline regions of the water hyacinths were also damaged during the reaction. Furthermore, the hemicellulose and cellulose in the water hyacinths were dissolved and hydrolyzed to reducing sugars in the reaction solution, and then the reducing sugars were further dehydrated to hydroxymethylfurfural (HMF) and furfural. Lignin in the water hyacinths was depolymerized into aromatic and hydrocarbon compounds. The process presented in this study effectively alleviates environmental pollution by efficient utilization of aquatic wastes, and it produces high-value chemicals from biomass waste.

  • Researchpp 2304-2327Sakdaronnarong, C., Srimarut, N., Chantasod, R., Sraphet, S., Triwitayakorn, K., and Jonglertjunya, W. (2018). "Enzyme matching design approach on very high gravity liquefaction and saccharification of cassava root and cassava starch for ethanol fermentation," BioRes. 13(2), 2304-2327.AbstractArticlePDF

    During ethanol production, the ratio of various sources of starch-hydrolyzing enzymes significantly influences hydrolysis efficiency in a very high gravity (VHG) system. In this study, the enzyme matching approach was proposed to optimize liquefaction and saccharification yield of cassava root and cassava starch. For fresh cassava root, the synergistic effect of using Techzyme Q-Add enzyme (93 °C pH 5.6) for liquefaction and GC 147 enzyme (61.5 °C pH 4.2) for saccharification achieved the highest yield among all enzyme-matching designs. At 25% solid, highest total reducing sugar (TRS) yields from sequential liquefaction and saccharification of cassava starch, fresh cassava, and dry cassava were 87.9%, 85.1%, and 70.0% corresponding to 286.8, 249.4, and 241.1 g/L, respectively. For VHG ethanol fermentation by Saccharomyces cerevisiae TISTR 5606, separate liquefaction and simultaneous saccharification and fermentation (SLSSF) gave a significantly higher ethanol concentration compared with separate liquefaction and saccharification and fermentation (SLSF). From a 35% solid SLSSF system, the highest ethanol produced at 30 °C was 27.3 g/L from 72 h, respectively. The results suggested that SLSSF could effectively shorten the time course of the whole process for liquefaction, saccharification, and fermentation from 74 h to only 26 h for similar ethanol production yields.

  • Researchpp 2328-2341Gou, G., Wang, Q., Xie, W., Cao, J., Jiang, M., He, J., and Zhou, Z. (2018). "Assessment of instant catapult steam explosion treatment on rice straw for isolation of high quality cellulose," BioRes. 13(2), 2328-2341.AbstractArticlePDF

    Instant catapult steam explosion (ICSE) was applied to treat rice straw for isolating high quality cellulose. After ICSE treatment under the condition of maintaining the pressure at 2.0 MPa for 11 min, the hemicellulose content decreased to 3.70% from the original 20.10%, and the content of α-cellulose was 72.02%. The enormous explosion power density provided by ICSE turned rice straw into cellulosic fibers with good accessibility, as well as it protected the cellulose fibers from being over-hydrolyzed. All of the straw cellulosic samples were analyzed by scanning electron microscopy (SEM), Fourier transformation infrared spectrometry (FTIR), and X-ray diffraction (XRD) to collectively examine the impact of ICSE treatment on the structure and morphology of the cellulose components. The recycled lignin was also analyzed by two-dimensional nuclear magnification resonance spectrometry (2D NMR) to understand the mechanisms underlying the ICSE treatment.

  • Researchpp 2342-2355Knapic, S., Grahn, T., Lundqvist, S. O., and Pereira, H. (2018). "Juvenile wood characterization of Eucalyptus botryoides and E. maculata by using SilviScan," BioRes. 13(2), 2342-2355.AbstractArticlePDF

    The wood properties of 6-year-old Eucalyptus botryoides and Eucalyptus maculata point towards a possible aptitude for solid-wood end uses. Samples from E. botryoides and E. maculata were characterized regarding within-tree variation in wood density, radial and tangential fibre width, fibre wall thickness, fibre coarseness, microfibril angle, and stiffness based on SilviScan measurements taken radially from the pith outwards at varying stem height levels. The mean values of the studied wood properties for E. botryoides and E. maculata were, respectively: density 507 kg m-3 and 695 kg m-3, radial fibre width 17.4 µm and 17.2 µm, tangential fibre width 16.7 µm and 16.9 µm, fibre wall thickness 1.8 µm and 2.5 µm, fibre coarseness 161.2 µgm-1 and 212.9 µgm-1, microfibril angle 15.5° and 14.7°, and stiffness 9.6 GPa and 12.1 GPa. The variation in wood stiffness was explained to a large extent by microfibril angle and wood density variations. The results of the scans, along with the wood variability, indicated that both species should be considered for solid wood products or pulp production.

  • Researchpp 2356-2373Xu, J., Li, M., and Sun, R. (2018). "Successive fractionations of hemicelluloses and lignin from sorghum stem by sodium hydroxide aqueous solutions with increased concentrations," BioRes. 13(2), 2356-2373.AbstractArticlePDF

    Sorghum stem, an agricultural solid waste discarded in large amounts, was effectively fractionated into its chemical components to achieve value-added utilization. The stem was successively extracted using water at 80 °C and alkali aqueous solutions with increased concentrations (1% NaOH; 60% ethanol containing 1% NaOH, 3% NaOH, 5% NaOH, and 8% NaOH) at 50 °C, which yielded hemicellulose and lignin fractions as well as a cellulose-rich residue. The hemicellulose and lignin fractions were characterized in terms of yield, sugar components, alkaline nitrobenzene, and oxidation analysis. In addition, the molecular weights were determined by gel permeation chromatography and the structures were further identified by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The results indicated that the hemicelluloses yielded from the alkali aqueous solution had a linear xylan structure. The alkali lignin had a typical guaiacyl/syringyl/p-hydroxypheny structure and low amounts of contaminating sugars (less than 2%). A high concentration of alkali aqueous solution led to the release of lignin with a large molecular weight, whereas increasing the alkali concentration resulted in lignin degradation. The residual stem after the successive extractions was rich in cellulose and had a low crystallinity. In sum, mild successive extractions are a promising way to fractionate sorghum stem waste for further conversion.

  • Researchpp 2374-2396Salanti, A., Zoia, L., Simonutti, R., and Orlandi, M. (2018). "Epoxidized lignin derivatives as bio-based cross-linkers used in the preparation of epoxy resins," BioRes. 13(2), 2374-2396.AbstractArticlePDF

    Lignin, which is the most abundant aromatic polymer in nature, was used as a green substitute for the toxic bisphenol A. In particular, the ability of epoxidized lignin to simultaneously serve as a cross-linker and rigid segment was investigated. The epoxidized lignin was preferably reacted with a monofunctional amine, which acted as a chain extender, to evaluate its performance as a cross-linker, and in the presence of poly(ethylene glycol) diglycidyl ether as a soft segment to adjust the resin properties. Different poly(ethylene glycol) diglycidyl ether/lignin stoichiometric ratios were tested, whereas the amine/epoxy equivalent ratio was fixed at 1:2. Some of the remarkable resin samples were subjected to differential scanning calorimetry analysis and compared with blank samples that did not include lignin in the composition. Moreover, the evolution over time of the molecular weight distribution of the selected compositions was analyzed by gel permeation chromatography until the solubility in tetrahydrofuran was appreciable.

  • Researchpp 2397-2410Zhang, L., Jia, Y., He, H., Yin, J., Chen, R., Zhang, C., Shen, W., and Wang, X. (2018). "Multiple factor analysis on preparation of cellulose Nanofiber by ball milling from softwood pulp," BioRes. 13(2), 2397-2410.AbstractArticlePDF

    This work aimed to investigate the effects of various single factors and their interactions on the preparation of cellulose nanofiber (CNF) using ball milling. These factors included the milling ball size, milling time, mass ratio of milling ball to cellulose pulp, and alkali concentration, as well as their complicated interactions. The Taguchi method was applied to the experimental design to systematically study the influences of these factors on the yield of CNF. A method for evaluating the yield of CNF was developed. Both of the simple analysis (SA) and analysis of variance (ANOVA) of the experimental results indicated that the most significant factor influencing the yield of CNF was the mass ratio of milling ball to cellulose pulp. The interactions between this factor and other single factors, e.g., milling time, also showed significant influence on the yield of CNF. Although the influence of milling ball size was negligible, its interaction with mass ratio of milling ball to cellulose pulp must be considered during production. Based on these findings, a mini scaled-up practice was proposed to demonstrate the possibility of the application of ball milling on the mass production of CNF.

  • Researchpp 2411-2423Song, X., Shangguan, W., Zhang, L., Yuan, Y., and Lei, Y. (2018). "Effect of different boiling treatments on physical properties of cork from Quercus variabilis," BioRes. 13(2), 2411-2423.AbstractArticlePDF

    Effects of different boiling treatments were evaluated relative to various physical properties of cork from Quercus variabilis before and after treatment, including volume, density, hardness, compression resilience ratio, and color. The boiling water treatment decreased the density, hardness, and lightness of cork. Water absorption amount of cork boiled at 100 °C for 30 min to180 min increased from 28.85% to 52.50%, and expansion in the radial direction was 15.4% to 19.5%. The total color difference (ΔE*) of cork gradually increased with increased boiling time. The values of the compression resilience ratio of all corks after a pressure release at 24 h were >80%. Cork samples boiled at 100 °C for 60 min, and then dried under different temperatures (140 °C to 240 °C), had volume expansion between 35.6% and 65.3%. With increased drying temperature, the ΔE* of cork increased. Cork boiled at 100 °C for 60 min followed by microwave irradiation of different times (2 min to 8 min) had volume expansion of 39.7% to 54.5%. Microwave treatment had little influence on cork color. The sodium hydroxide solution boiling treatment decreased cork lightness, while the hydrogen peroxide-treated cork lightness increased with the increasing of solution concentration, and ΔE* slightly increased.

  • Researchpp 2424-2439Záborský, V., Borůvka, V., Kašičková, V., and Gaff, M. (2018). "The effect of selected factors on Domino joint stiffness," BioRes. 13(2), 2424-2439.AbstractArticlePDF

    When designing wooden structures and furniture, it is very important to consider joints that allow the structure to stay together and upright. There are many different types of wood joints. The selection of a joint type and its properties are some of the most important design choices. This article was dedicated to the Domino joint, which allows for strong joints. The Domino joiner is a loose tenon and mortise manufacturing joining tool. This article discusses the effect of selected parameters, such as the type of stress (tensile and compressive), size of the Domino joiner (one-half and one-third thickness), wood species (beech (Fagus sylvatica L.) and spruce (Picea abies L.)), and adhesive type (polyvinyl acetate and polyurethane), on the joint stiffness. The influence of the annual rings was also monitored.

  • Researchpp 2440-2451Park, S. Y., Kim, J. C., Yeon, S., Yang, S. Y., Yeo, H., and Choi, I. G. (2018). "Rapid prediction of the chemical information of wood powder from softwood species using near-infrared spectroscopy," BioRes. 13(2), 2440-2451.AbstractArticlePDF

    Five different softwoods were used to investigate fast methods for predicting quantitative chemical information via near-infrared (NIR) spectroscopy. In biomass-related industries, fast collection of chemical information from a feedstock is needed. Prior to predicting quantitative information, a principal component analysis (PCA) using NIR spectra was conducted to evaluate the possibility of discriminating the softwoods. As a result of PCA, the five species were divided into three groups. This result indicated that the extractive compounds were key factors because the powder samples were separated by species having a similar extractive content. The partial least square (PLS) method was applied to develop a calibration model for predicting chemical composition. This model showed good performance in predicting the extractive and lignin content of all species. The calibration results of the extractive and lignin content for all species were indicated as R2 = 0.99. The cross-validation of the components for all species also showed an excellent value of R2 = 0.98 and 0.97, respectively. Based on our results, it was possible to suggest a useful tool for providing rapid information about wood used in the bioenergy and pulp production fields.

  • Researchpp 2452-2472Bikár, M., Sedliačiková, M., Vavrová, K., Moresová, M., and Hitka, M. (2018). "Does the combustion of biomass increase the efficiency of heating companies? Evidence from Slovakia," BioRes. 13(2), 2452-2472.AbstractArticlePDF

    Over the last decade, the consumption of renewable energy within the EU increased by 66%, and corporations have recognized that heating with wood waste is a cost-effective response to fluctuating fuel prices and a means of avoiding waste disposal costs. The main objective of this paper was to determine whether the combustion of biomass compared with the use of fossil fuels as the primary heat source would increase the efficiency in Slovak heating companies. This research was evaluated via methods of synthesis, analyses, and financial analyses. The survey found that heating companies with combined productions had better economic results. Based on the peer group comparison, heating companies using renewable resources achieved remarkably higher performance indicators. Among renewable energy sources, total biomass plays an important role and accounted for just over two thirds (64%) of the gross inland energy consumption of renewables in the EU. Wood pellets and agglomerates are currently the most economical way of converting biomass into fuel and are a fast-growing source of energy in Europe. The economic efficiency and key performance indicators strongly depend on the input prices of the energy carriers. In the last decade, the cost of heat produced from natural gas amounted on average to two to three times the cost of deciduous wood. Biomass production can generate employment, and if intensive agriculture is replaced by less intensively managed energy crops, there are likely to be environmental benefits, such as reduced leaching of fertilizers and reduced use of pesticides.

  • Researchpp 2473-2486Yu, Y., Jiang, X., Ramaswamy, H. S., Zhu, S., and Li, H. (2018). "Effect of high-pressure densification on moisture sorption properties of Paulownia wood," BioRes. 13(2), 2473-2486.AbstractArticlePDF

    The effect of high-pressure (HP) densification (30, 90, and 150 MPa for 3, 30, and 300 s) on the moisture sorption properties of Paulownia wood was investigated. After the densification, samples were conditioned at three temperatures (20, 30, and 40 °C) and five equilibrium moisture contents (from 11.20 to 95.62%) during the study, after which the equilibrium moisture contents of the control and treated samples were measured. The HP-treated groups had higher equilibrium moisture contents than the controls at higher relative humidity levels. The hysteresis phenomenon and the scanning electron microscopy observations were explained by the transformation of the structural elements by the HP treatment. Finally, two moisture sorption isotherm (MSI) models (a linear polynomial model for adsorption and a quadratic polynomial model for desorption) were established with good performance to describe the relationship between HP treatment parameters, environmental conditions, and equilibrium moisture contents.

  • Researchpp 2487-2498Liang, F., Fang, G., Jiao, J., Deng, Y., Han, S., Shen, K., Shi, Y., Li, H., Zhu, B., Pan, A., and Tian, Q. (2018). "The use of twin screw extruder instead of model screw device during bamboo chemo-mechanical pulping," BioRes. 13(2), 2487-2498.AbstractArticlePDF

    Bamboo is one of the most important raw materials for pulp and paper production in several countries due to its abundance and cost-effectiveness. However, the difficulties in bleaching and low brightness of bamboo chemo-mechanical pulp (CMP) has limited the expansion of its utilization. In this study, the low-cost twin-screw extruder (TSE) was used instead of the high-cost common extruded model screw device (MSD) before chemical impregnation to improve the brightness of the bamboo CMP. There were minor differences in the holocellulose, lignin, and pentose contents in the extruded materials between the two devices. The absorbency of the TSE extruded materials was 4.50 g/g, which was three times that of the material extruded by MSD. Alkali optimization was conducted at levels of 12% H2O2. The TSE-CMP achieved the highest brightness, at 57.6% ISO with 6% sodium hydroxide (NaOH), while the MSD-TMP only reached approximately 49.6% ISO with 3% NaOH. At the same time, the physical properties of paper-sheets made from bleached TSE-CMP and MSD-CMP were tested. When bleached at 12% H2O2 with 6% NaOH, the tensile index of TSE-CMP was higher compared with that of MSD-CMP, while the other strength properties were nearly unchanged.

  • Researchpp 2499-2514Ye, H., Zhang, Y., and Yu, Z. (2018). "Wood flour’s effect on the properties of geopolymer-based composites at different curing times," BioRes. 13(2), 2499-2514.AbstractArticlePDF

    Fly-ash (FA) /wood-flour (WF) geopolymer composites (FWGCs) were prepared to investigate the influence of WF on the properties of FA-based geopolymer composites at different curing times. The crystallization, surface morphology, geopolymerization, interface analysis, and mechanical properties were characterized. The results indicated that the curing time exerted positive effects on the mechanical strength of the FWGCs. Noticeably distinct microstructures and mechanical properties were observed with different WF contents. The FWGCs with low WF loading (1 wt% and 5 wt%) presented almost unchanged or even improved mechanical properties compared to the pure FA-based geopolymer due to the existence of bonds between the WF and geopolymer matrix in the interface. However, the addition of WF to a higher content (10 wt%, 15 wt%, and 20 wt%) posted a negative influence on mechanical properties with insufficient polymerization of geopolymer and degradation of WF detected by morphology and elemental microanalysis. This study will facilitate a better understanding of the interaction between geopolymers and wooden materials, and serve as a basis for further research and applications.

  • Researchpp 2515-2529Kubovsky, I., Kacik, F., and Velkova, V. (2018). "The effects of CO2 laser irradiation on color and major chemical component changes in hardwoods," BioRes. 13(2), 2515-2529.AbstractArticlePDF

    The influence of laser radiation was evaluated relative to the color and major chemical component changes of three hardwood species. The surfaces of maple (Acer pseudoplatanus L.), beech (Fagus sylvatica L.), and lime (i.e. linden, Tilia vulgaris) wood were exposed to radiation from a CO2 laser (wavelength = 10.6 µm, output power = 45 W). It was observed that increased doses of irradiation resulted in a decrease in the lightness (L*), increase in the total color difference, and a drop in the total polysaccharide content. Compared with the non-irradiated specimens, the ΔL* values at the highest irradiation doses were −56 (maple), −46.8 (beech), and −50.5 (lime). The trends observed in the FTIR spectra also showed there was a relationship between the breaking of C=O and C=C bonds in important functional groups in the lignin, hemicellulose, and carbohydrates. A highly linear correlation (R2 from 0.902 to 0.987) was observed between the increase in the ΔL* and decrease in the hemicellulose content, which degrades faster than other basic wood components. Such a phenomenon may have been related to the formation of new chromophore structures, which caused the color changes in the wood.

  • Researchpp 2530-2545Huan, Z., Jiao, Z., Li, G., and Wu, X. (2018). "Velocity error correction based tomographic imaging for stress wave nondestructive evaluation of wood," BioRes. 13(2), 2530-2545.AbstractArticlePDF

    Stress wave testing has been applied in the nondestructive evaluation of wood for many years. However, the anisotropy property of wood and the limited number of sensors prevent an accurate stress wave velocity measurement and the high resolution of tomographic inversion. This paper proposes a tomographic imaging algorithm (IABLE) with a velocity error correction mechanism. The proposed algorithm computed the wave velocity distribution of the grid cells of wood cross-sections by the least square QR decomposition (LSQR) iterative inversion, and then optimized the tomography with a velocity error correction mechanism (ECM). To evaluate the performance of the proposed algorithm, several healthy and defective logs and live trees were selected as the experimental samples, and the nondestructive testing procedures were finished. With the stress wave velocity data sets measured via a PiCUS 3 stress wave testing instrument, the IABLE algorithm was implemented, and the tomographic images of the log samples and live trees were generated. The experimental results demonstrated the effectiveness of the proposed imaging algorithm for the nondestructive evaluation of wood.

  • Researchpp 2546-2561Gajdačová, P., Hýsek, Š., and Jarský, V. (2018). "Utilisation of winter rapeseed in wood-based materials as a solution of wood shortage and forest protection," BioRes. 13(2), 2546-2561.AbstractArticlePDF

    Due to various factors, there is evidence that there will be a future lack of wood materials in the woodworking and energy sectors, as well as other sectors. This has been confirmed definitively through the most recent developments. Possible solutions include the partial replacement of wood in composite materials by post-harvest remnants of agricultural crops. Unlike wood matter, however, these stems need surface pre-treatment before they can be used to produce composite materials. In this study the effects were compared for two pre-treatments of stems (alkaline and hydrothermal) of rapeseed (Brassica napus L.), maize (Zea mays L.), and wheat (Triticum aestivum L.). The effects were compared using the contact angle between water and the surfaces of the stems. Hydrothermal modification yielded a statistically significant reduction in the contact angle between water and the stem surfaces of winter rapeseed and maize; likewise, alkaline modification yielded a statistically significant reduction in the contact angle between water and the stem surface of maize. The possibility of using winter rape to produce composite materials was further evaluated and comprehensively assessed using SWOT analysis.

  • Researchpp 2562-2577Long, Z., Wu, J., Xu, W., and Lin, W. (2018). "Study of the coordination mechanism of a wood processing residue-based reverse supply chain," BioRes. 13(2), 2562-2577.AbstractArticlePDF

    A revenue-sharing contract was introduced into a three-echelon wood processing residue-based reverse supply chain model to maximize the supply chain profit and realize a win-win situation for all participants. The optimal expected supply chain profits under different decision policies and the acceptable range of revenue-sharing coefficients were analyzed. Finally, the model was applied in a case study where sawdust was recycled to produce black fungus. Results showed that revenue-sharing can effectively enable supply chain coordination. Within the domain of the revenue-sharing coefficients, the production cost decreased by 5.91% and the corresponding demand increased by 16.09%, resulting in an increase of 7.73% in the supply chain profit. A comparison was made between the three-echelon and a two-echelon supply chains, and the results showed that the two-echelon supply chain would become less competitive than the three-echelon supply chain with the increase of recycling cost. Additionally, the profit shares of all parties in the three-echelon supply chain depended mainly on the revenue-sharing coefficients, which were determined by the positions of the parties and their bargaining power.

  • Researchpp 2578-2591Yang, F., Ma, H., Tang, L., and Feng, Y. (2018). "Effect of polyvinyl alcohol treatment on mechanical properties of bamboo/polylactic acid composites," BioRes. 13(2), 2578-2591.AbstractArticlePDF

    Polylactic acid (PLA) and bamboo fiber are both green and biodegradable materials. However, the bonding of PLA and bamboo fiber is poor, which limits the physical properties of paper. The effects of polyvinyl alcohol (PVOH) on PLA fiber/bamboo fiber composites were studied by measuring the tensile strength, tear resistance, and breaking length of the paper. In addition, the morphology of paper comprised of PLA fiber and bamboo fiber were investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The tensile index, tear index, and breaking length of paper made with the 4 wt% PVOH-treated bamboo fiber and the untreated PLA fiber compared favorably with the paper made of the untreated bamboo fiber and PLA fiber increased 21.0%, 8.6%, and 20.8%, respectively. However, compared with the paper made of the untreated bamboo fiber and PLA fiber, the tensile index, tear index, and breaking length of the paper made with the treated PLA fiber and the treated bamboo fiber with 4 wt% PVOH solution were dramatically reduced by 30%, 18%, and 30%, respectively.

  • Researchpp 2592-2601Hýsek, Š., Šedivka, P., Böhm, M., Schönfelder, O., and Beran, R. (2018). "Influence of using recycled polyurethane particles as a filler on properties of polyurethane adhesives for gluing of wood," BioRes. 13(2), 2592-2601.AbstractArticlePDF

    Fillers can greatly affect the properties of adhesives, and this research aimed at enhancing the performance of adhesives by using different concentrations of fillers. This paper describes the influence of using recycled polyurethane particles (powder of particle size from 10 µm to 50 µm) as a filler on some properties of polyurethane adhesives for the gluing of wood. Two kinds of one-component, moisture-curing polyurethane adhesives were used. The observed properties were the contact angle between the wood and adhesive droplet, and the strength of bonded joints (shear strength). From the results, it was concluded that the contact angle increased with an increase in filler (in the entire observed range from 0% to 15% filler). The content of filler also affected the strength of bonded joints and their thermal stability. The strength of bonded joints decreased with an increase in filler content when samples were conditioned in cold water. However, the strength of bonded joints increased with an increase in filler content when samples were boiled in water.

  • Researchpp 2602-2616Pesenti, H., Zumelzu, E., Gacitua, W., Torres, M., Castillo, J., Sanchez, A., Leoni, M., and Dodoo-Arhin, D. (2018). "Characterizing Teline monspessulana as a green sustainable source of biofibers," BioRes. 13(2), 2602-2616.AbstractArticlePDF

    Invasive Teline monspessulana can be an important source of biomass to supply fibers for the rising demand of cellulose bioproducts, especially for the development of advanced materials. Its fibers can be extracted via a thermo-alkaline process at 170 °C with 40 g/L of sodium hydroxide (NaOH) and characterized by crystallographic, thermo-analytical, and mechanical techniques. The cellulose proportion in the wood of this species is approximately 47.6 wt.% ± 1.05 wt.%. However, its fibers are relatively small, and they have a wide range of aspect ratios from 25 to 287, with an average diameter of 9.3 μm ± 2.5 μm. These characteristics and mechanical properties make the fibers unattractive for the textile and paper industries. Meanwhile, crystalline cellulose was prevalent in the monoclinic phase, with a crystalline index and crystalline portion of 78 and 41%, respectively, observing crystal domains of c.a. 3.2 nm. Nanoindentation tests revealed favorable values of elastic modulus and hardness of c.a. 16 GPa and 0.28 GPa, respectively. Thus, this bioresource is expected to see promising applications in materials engineering, such as reinforcement in material composites, in drug delivery carrier, and electronic devices, among other biomultifunctional components.

  • Researchpp 2617-2631Wang, S., Lv, M., Yang, J., Zhou, Y., and Xu, B. (2018). "Effects and mechanism of metal ions on enzymatic hydrolysis of wheat straw after pretreatment," BioRes. 13(2), 2617-2631.AbstractArticlePDF

    The effects and mechanism on the enzymatic hydrolysis of lignocellulose by metal ions were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), Fluorescence Spectra, and enzymatic kinetics and activity analyses of the enzymatic hydrolysis system. Fe3+ exerted the best enzymatic hydrolysis effect on pretreated wheat straw, and the highest reducing sugar conversion was 44.5%. SEM and FTIR indicated that alkali and ultrasonic pretreatments partially removed the lignin and hemicellulose from lignocellulose. DLS and fluorescence spectra results revealed that the electrostatic interaction between Fe3+ and the carboxyl group in the enzyme enlarged the enzyme’s steric structure. The data on enzymatic kinetics displayed that Fe3+ increased the maximum rate of reaction by 33.9% and the Michaelis-Menten by 5.72 g/L. The enzyme activity increase rate rose initially and then diminished, and the maximum increase rate was 36.1%.

  • Researchpp 2632-2657Pires, A., Han, Y., Kramlich, J., and Garcia-Perez, M. (2018). "Chemical composition and fuel properties of alternative jet fuels," BioRes. 13(2), 2632-2657.AbstractArticlePDF

    The chemical composition and fuel properties of nine alternative jet fuels (named as AJF 1-9) and three commercial jet fuels (named as CJF 1, 2 and 3) are reported in this work. The fuels were characterized by GC/MS, SEP-GC/MS (for quantification of oxygenated molecules), viscosity, density, water content, water solubility at 0 °C, carbonyl content, total acid number, elemental composition, calorific value, flash point, differential scanning calorimetry, and surface tension. The content of n-paraffins, iso-paraffins, olefins, naphthenes, and aromatics are reported. The fuel rich in aromatics (AJF 1) has the highest density (0.90 g/mL), C content (over 90 wt. %), and water solubility, lowest calorific value, and high surface tension. The fuels with high contents of light molecules have the lowest flash points (AJFs 1, 6, and 8). AJF 2 is the most viscous fuel due to the presence of a single relatively heavy molecule. The content of oxygenated compounds measured was in all the cases very low and comparable with the amount found in commercial jet fuels. Overall, these fuels comply with most of ASTM requirements and offer opportunities to develop specialized products.

  • Researchpp 2658-2669Yu, H., Du, C., Huang, Q., Yao, X., Hua, Y., Zhang, W., Zhou, Z., and Liu, H. (2018). "Effects of extraction methods on anti-mould property of bamboo strips," BioRes. 13(2), 2658-2669.AbstractArticlePDF

    To achieve improvements in anti-mould properties, bamboo strips were subjected to extractions with different combinations of extraction media: boiling water, 1.0 wt.% hydrochloric acid (HCl), or 1.0 wt.% sodium hydroxide (NaOH). The impacts of different extraction methods on the structure and anti-mould properties of bamboo strips were investigated. The results suggested that bamboo strips treated alternatively with different extraction media were free of changes in crystalline structure and cell morphology but showed partial degradations of hemicellulose and decreases in the amount of free hydroxyl groups. As a result of these treatments, elimination or migration of extractives (including starch, soluble saccharides, and aliphatics) improved the resistance of bamboo strips to Penicillium citrinum, Trichoderma viride, Aspergillus niger, and a mixture of these mildews. Among the tested treatments, sequential extraction with boiling water, 1.0 wt.% NaOH, and 1.0 wt.% HCl resulted in a mildew-preventing efficiency of 96.9%, indicating optimum anti-mould properties.

     

  • Researchpp 2670-2677Long, J., Gong, H., Zhang, D., Liu, M., and Li, H. (2018). "Determination of carboxyl groups in pulp via ultraviolet spectrophotometry," BioRes. 13(2), 2670-2677.AbstractArticlePDF

    A method was established for the determination of carboxyl groups in pulp by ultraviolet (UV) spectrophotometry. The method is based on the fact that the carboxylate pretreated with diluted hydrochloric acid was completely converted to carboxylic acid in pulp. In addition, content of carboxyl groups was measured with the capacity of copper ions exchanged with the hydrogen ions of carboxylic acid by UV spectrophotometry. The data showed that the pulp was suitable to react with 30% to 50% exchanged copper ions for 4 h at 45 °C. The results indicated that the method had excellent repeatability (RSD = 1.50%) and accuracy. Compared to traditional methods, the maximum relative error was less than 4%. The method is simple and accurate, such that it can be used for the efficient determination of carboxyl groups in pulp and other researches.

  • Researchpp 2678-2701Tisserat, B., Hwang, H., Vaughn, S. F., Berhow, M. A., Petersen, S. C., Joshee, N., Vaidya, B. N., and Harry-O’Kuru, R. (2018). "Fiberboard created using the natural adhesive properties of distillers dried grains with solubles," BioRes. 13(2), 2678-2701.AbstractArticlePDF

    Distillers dried grains with solubles (DDGS) were employed as a bio-based resin/adhesive. DDGS were defatted with hexane, ball ground, and screened prior to use. DDGS flour was mixed dry with Paulownia wood (PW) to make composites using the following conditions: temperature of 150 to 195 °C, PW particle sizes of £ 75 to 1700 mm, pressure of 2.1 to 5.6 MPa, and using DDGS dosages of 10 to 100%. Molded composites were evaluated for their flexural properties. Composites were examined with Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction.  The best flexural properties were obtained from composites containing 50% DDGS and 50% PW, using 180 to 250 mm PW particles, pressed at 5.6 MPa, and employing 185 °C. Flexural properties of DDGS-PW composites were similar to composites fabricated using soybean flour (Prolia) as the resin/adhesive. Dimensional stability properties (water absorbance and thickness swelling) of DDGS-PW and Prolia-PW composites were similar. DDGS-PW composite properties satisfied several European Committee Industry Standards for fiberboards in terms of flexural properties but were inferior in terms of thickness swelling properties.

  • Researchpp 2702-2714Durcan, F. M., and Burdurlu, E. (2018). "Effects of some machining parameters on noise level in planing of some wood materials," BioRes. 13(2), 2702-2714.AbstractArticlePDF

    Effects of type of wood, number of blades, and depth and width of cutting were evaluated relative to the noise level during the machining of wooden materials in a spindle moulder. Lombardy poplar, Oriental beech, and medium density fibreboard (MDF) materials, at the thickness levels of 6 mm, 12 mm, 18 mm, 25 mm, or 30 mm, were planed for 20 min for each variable at the feed rate of 5 meters per min and at the cutting depth of 1 mm, 2 mm, or 3 mm with one or four blades. During machining of the samples, the noise levels were measured using a noise level meter. According to the data obtained, the highest noise level connected to the type of materials was measured in the machining of poplar wood, followed by that of beech wood and MDF. As the thicknesses of the materials were increased, increases up to 9 dBA of the noise level were measured. Moreover, machining the materials with one blade instead of four and with a cutting width of 1 mm instead of 3 mm increased the noise level by 2 dBA and 6 dBA, respectively.

  • Researchpp 2715-2726Choi, C., Kojima, E., Kim, K., Yamasaki, M., Sasaki, Y., and Kang, S. (2018). "Analysis of mechanical properties of cross-laminated timber (CLT) with plywood using Korean larch," BioRes. 13(2), 2715-2726.AbstractArticlePDF

    The bending strength of hybrid wooden-core laminated timber (HWLT), a composite material made from existing cross-laminated timber (CLT) and plywood, was analyzed. Using plywood makes it possible to decrease the bending strength of the starting material. Korea Larch (Larix kaempferi Carr.) was used as plywood because of its popularity in Korea. To analyze HWLT’s bending properties, each component (lamina, plywood) was tested for bending, compression, and tensile strengths. The results showed that the HWLT’s bending strength depended on the plywood’s number of plies. With an increased number of plies, plywood’s bending strength decreased, and also HWLT’s bending strength decreased. Most of the failure showed in-plate shear failure of plywood. This result meant that use of reinforced plywood made it possible to increase HWLT’s bending strength for structural material.

     

  • Researchpp 2727-2747Grenda, K., Arnold, J., Hunkeler, D., Gamelas, J., and Rasteiro, M. (2018). "Tannin-based coagulants from laboratory to pilot plant scales for coloured wastewater treatment," BioRes. 13(2), 2727-2747.AbstractArticlePDF

    Bark tannin extract from Acacia mearnsii (Mimosa ME) was modified at laboratory and pilot plant scales via the Mannich condensation reaction using formaldehyde and dimethylamine hydrochloride. Several conditions were varied during the modification procedure (heating rate, formaldehyde dosage, and Mannich solution activation time) to evaluate their influence on the shear viscosity and shelf life of the resulting products. It was possible to tune these properties with the reaction conditions. Modified condensed tannins with five distinct shear viscosities (30 cP to 430 cP) were selected to test the colour removal of anionic (Duasyn Direct Red and Acid Black 2) and cationic (Methylene Blue and Crystal Violet) dyes. The performance was monitored by ultraviolet spectroscopy. Colour removal was studied over different pH levels (1 to 14). Good decolouration results (85% to 96% reduction) were obtained with the simultaneous introduction of other additives to the process, which were bentonite and a cationic or anionic polyacrylamide, with minimal dosages of the latter additives. An improvement to decolouration performance with an increase in the biocoagulant viscosity was typically observed. However, for practical applications, modified condensed tannins with a lower viscosity may be preferred because they exhibited a longer shelf life and presented reasonable removal efficiencies.

  • Researchpp 2748-2758
    He, X., Zhang, K., Wang, W., Li, H., and Yin, Q. (2018). "Thermal stability and bonding mechanisms of corn stalk rind," BioRes. 13(2), 2748-2758.
    AbstractArticlePDF

    Removing the epidermis of corn stalk rind can remarkably improve its bonding properties. This study aimed to determine the plate-making process by using intact corn stalk rind and thus utilize the crushed, removed epidermis. The thermal stability of corn stalk rind was investigated before and after removing the epidermis and gluing of the material using the hyphenated technique by simultaneous thermal analysis (STA), Fourier transform infrared spectroscopy (FT-IR), and gas chromatography-mass spectrometry (GC-MS). The results showed that the epidermis of corn stalk rind, from 90 °C to 200 °C, was conducive to softening the lignin in corn stalk rind and solidifying it as an adhesive. When the temperature was higher than 220 °C, the rate of weight loss rapidly increased and the thermal decomposition of hemicelluloses and cellulose in corn stalk rind after gluing was accelerated. The bonding process of corn stalk rind and adhesives is extremely complex, and intricate physical and chemical changes occur. Adhesive filled the surface cracks and depressions on the corn stalk rind, which not only improved its thermal stability, but also fixed corn stalk rind by forming connections.

  • Researchpp 2759-2774Hitka, M., Lorincová, S., Pajtinková Bartáková, G., Ližbetinová, L., Štarchoň, P., Li, C., Zaborova, E., Markova, T., Schmidtová, J., and Mura, L. (2018). "Strategic tool of human resource management for operation of SMEs in the wood-processing industry," BioRes. 13(2), 2759-2774.AbstractArticlePDF

    The aim of this study was to identify the differences in the perception of the preferred level of corporate culture in Europe (Czech Republic and Slovak Republic), Asia (the People’s Republic of China (Beijing Municipality), and the Russian Federation (Sverdlovsk region). The research methodology was based on the Organizational Culture Assessment Instrument, which is a well-known and widely used measurement tool developed by Cameron and Quinn (1999). Based on statistical verification through an analysis of variance and Tukey’s honest significant difference (HSD) test, similarities in corporate cultures were seen for employees working in the Czech Republic, Slovak Republic, and People’s Republic of China, and there was a demand for a clan corporate culture. In the Russian Federation, employees preferred market and hierarchy corporate cultures. Furthermore, the corporate culture within the Baby Boomer, X, and Y generations was analysed. Within generations, major inter-regional differences were not confirmed. A positive corporate culture can contribute to further strategic development of companies and successful operation in the market.

  • Researchpp 2775-2784Hota, H., Mori, Y., and Kasuya, N. (2018). "One-pot synthesis of 5-hydroxymethylfurfural using a homogeneous aqueous solution of cellulose (cellulose-LiBr-H2O) and combined metal (II)- surfactant catalyst," BioRes. 13(2), 2775-2784.AbstractArticlePDF

    One-pot synthesis of 5-hydroxymethylfurfural (HMF) from cellulose or glucose through employing a concentrated solution of LiBr as solvent together with a combined metal (II) and surfactant catalyst was studied. First, cellulose was dissolved in the solvent, and then it was hydrolyzed with hydrogen bromide (HBr) under moderate conditions before the solution was neutralized. The next step toward HMF synthesis was performed at 140 °C for 3 h with the addition of the abovementioned catalyst at a 10 mol% level of the substrate. Metal (II) chlorides that could serve as a Lewis acid (i.e., catalysts), or combined metal (II) and surfactant catalysts, were adopted for converting glucose to HMF. The yield of HMF reached 30.5% from glucose, and 33.8% from cellulose when tin (II) dodecylsulfate was used as a Lewis acid catalyst. The catalyst containing tin (II) yielded better results than those that contained zinc (II) or copper (II).

  • Researchpp 2785-2799Phonetip, K., Ozarska, B., Brodie, G., Belleville, B., and Boupha, L. (2018). "Applying a GIS-based fuzzy method to identify suitable locations for solar kilns," BioRes. 13(2), 2785-2799.AbstractArticlePDF

    The aim of this study was to identify suitable locations for solar kilns in Vientiane, the capital of Laos, based on geographical and climatic conditions and restricted areas. The criteria of the parameters, which were incorporated with Fuzzy membership functions, were used to create layers in the ArcGIS environment to draw maps of suitability. Climatic parameters, based on the Fuzzy method, were used to investigate the period of productive performance for solar kilns. The results showed a range of possible locations. The most suitable locations were in flat areas near roads. They were far from protected areas, rivers, and flood prone areas. The most productive performance period for operating solar kilns was from November until May.

  • Researchpp 2800-2813Pintor-Ibarra, L. F., Rivera-Prado, J. J., Ngangyo-Heya, M., and Rutiaga-Quiñones, J. G. (2018). "Evaluation of the chemical components of Eichhornia crassipes as an alternative raw material for pulp and paper," BioRes. 13(2), 2800-2813.AbstractArticlePDF

    Eichhornia crassipes biomass collected in Lake Cuitzeo, Mexico was analyzed to determine the chemical components (pH, ash, ash microanalysis, extractives, lignin, holocellulose, and alpha cellulose) in the whole plant, as well as segmented analysis in roots, stems, and leaves. The plant contained an ash content of 14.3 to 20.7% and extractives content from 21.8 to 35.6%. The inorganic elements detected were potassium (K), chlorine (Cl), calcium (Ca), sodium (Na), magnesium (Mg), silicon (Si), aluminum (Al), phosphorous (P), sulfur (S), manganese (Mn), iron (Fe), and titanium (Ti). In addition, low amounts of lignin (12.5 to 25.7%) and holocellulose (26.7 to 37.1%) were obtained. Thus, E. crassipes biomass could complement cellulosic fibers in pulping processes of low yield, such as the fibers used to produce handmade paper.

  • Researchpp 2814-2833Huang, Z., Chen, Z., Huang, D., Chui, Y., and Bian, Y. (2018). "An inelastic model for analyzing intermediately slender engineered bamboo/wood columns subjected to biaxial bending and compression," BioRes. 13(2), 2814-2833.AbstractArticlePDF

    The engineered bamboo/wood composites (EBWCs) studied in this work included solid wood, wood-based composites, and bamboo-based composites. The basic characteristic of these products is that they have similar stress-strain relationships in the parallel to the grain direction because of their similar microscopic structures. The asymmetric stress-strain relationship in tension and compression presents a great challenge for the inelastic analysis of intermediately slender EBWC columns. In this study, a novel model was developed for the inelastic analysis of biaxially loaded intermediately slender EBWC columns with rectangular cross sections. The model provides a step by step method to evaluate the nonlinear responses and load-carrying capacities of these columns. Experiments on parallel strand bamboo columns loaded with biaxial eccentric loads were conducted to validate the model. Good agreement between the experimental and predicted results was achieved. The innovative elements of the model were the asymmetric properties of EBWCs in tension and compression, and its simplicity, which lends itself to implementation in engineering design calculations. The present work is an extension of a previous study by Huang et al. (2015a), and its objective was to develop an innovative inelastic analysis model evaluating biaxially loaded intermediately slender EBWC columns with rectangular cross sections.

  • Researchpp 2834-2845Palma, S., Goncalves, R., Trinca, A., Costa, C., Reis, M., and Martins, G. (2018). "Interference from knots, wave propagation direction, and effect of juvenile and reaction wood on velocities in ultrasound tomography," BioRes. 13(2), 2834-2845.AbstractArticlePDF

    Acoustic tomography is based on the velocity variation inside the inspected element. However, wood is heterogeneous and anisotropic, which causes natural velocity variations. In wood, the great challenge to apply this technology is to interpret and differentiate the natural variations of the material from those caused by deterioration. This study aimed to evaluate the interference caused by knots, the wave propagation direction, and the effect of juvenile and reaction wood on the velocities determined via ultrasonic tomography. The tests were performed using 40 disks of Pinus elliottii. From the results it was concluded that intrinsic orthotropy of the wood was reflected in the wave propagation on the disks with radial velocities greater than the tangential ones, higher velocities in the knot zones, and different velocities in the zones of compression and opposition wood. In the measurements using the diffraction mesh, the edge velocities (tangential direction with the maximum angle from the radial direction) were always lower than all of the other velocities in the disk. More significant variations in the velocity were obtained in the juvenile wood. These results contribute to quantifying some interferences associated with tomography images, such that the misinterpretation can be minimized.

  • Researchpp 2846-2860Gong, J., Shao, T., and Wang, K. (2018). "Synergetic effect and product characteristics of coal and Salix psammophila co-pyrolysis," BioRes. 13(2), 2846-2860.AbstractArticlePDF

    The co-pyrolysis of Salix psammophila and coal was conducted in a pyrolysis reactor. The interaction between coal and S. psammophila at different ratios was investigated. It was found that the promotion and inhibition effects were more obvious at 20 wt.% and 40 wt.% Salix psammophila, respectively, indicating a certain synergistic effect. The results of the N2 adsorption-desorption experiment showed that the addition of S. psammophila increased the surface area and decreased the pore size of the co-pyrolysis char. The Fourier transform infrared (FT-IR) spectra indicated that the pyrolysis tar contained mainly aromatic rings and fatty compounds. The addition of S. psammophila was beneficial to the decomposition of phenolic hydroxyls, ether bonds, and oxygen-containing heterocyclic rings in the coal tar. However, the addition of 50 wt.% S. psammophila blocked the pores of the coal and thus obstructed its pyrolysis, while the porosity of the co-pyrolysis char became more abundant. Richer porosity of the char implies great potential to be widely used in the sewage treatment industry.

  • Researchpp 2861-2870Zhou, S., Li, Y., Huang, L., Chen, L., and Miao, Q. (2018). "Enhanced reactivity of kraft-based viscose-grade dissolving pulp by Hollander beating treatment," BioRes. 13(2), 2861-2870.AbstractArticlePDF

    The reactivity of rayon-grade dissolving pulp is an important parameter in the subsequent production of viscose fiber. It can determine the processability and the quality of the viscose fiber. This study focused on improving the reactivity of kraft-based rayon-grade dissolving pulp through a mechanical treatment with mechanical refining, which could induce more fiber ends and channels or reactive sites via fiber cutting and fibrillation. Results showed that the Fock reactivity of a softwood kraft-based dissolving pulp increased from 54.4% to 68.4%, and the viscose filterability improved from 3743 s to 11 s when the beating degree of dissolving pulp was increased from 9 ºSR to 16 ºSR. Such a treatment also led to increases in the fines content, pore diameter, water retention value, and specific surface area while decreasing the fiber length. Meanwhile, it was beneficial that the intrinsic viscosity of dissolving pulp fiber was almost unaffected by the beating treatment.

  • Researchpp 2871-2886Smardzewski, J., and Łabeda, K. (2018). "Mechanical and hygroscopic properties of Longitudinally-Laminated Timber (LLT) panels for the furniture industry," BioRes. 13(2), 2871-2886.AbstractArticlePDF

    One likely reason why cross-laminated timber (CLT) panels are not applied in furniture designing is their unaesthetic appearance, with a crosswise arrangement of layers visible on narrow surfaces of furniture panels. The objective of this investigation was to manufacture and determine physic-mechanical properties of solid and cell Longitudinally-Laminated Timber (LLT) panels. The cognitive goal of the performed experiments was to determine orthotropy, linear elasticity moduli, and bending strength of LLTs. It was also decided to ascertain swelling coefficients of composites caused by changes in air humidity. Advantageous MOE and MOR values of LLTs were determined in relation to similar solid panels. In addition, it was demonstrated that, for furniture panel designing, it was rational to employ facings from beech wood as well as cores from beech wood free from anatomical defects.

  • Researchpp 2887-2897Azimvand, J., Didehban, K., and Mirshokrai, S. (2018). "Preparation and characterization of lignin polymeric nanoparticles using the green solvent ethylene glycol: Acid precipitation technology," BioRes. 13(2), 2887-2897.AbstractArticlePDF

    Alkali lignin (AL) was prepared by the acidification of black liquor obtained from a pulp and paper factory. The average molecular weight of the AL (2,530 g/mol) was determined using gel permeation chromatography (GPC). Alkali lignin modified by ethylene glycol and lignin nanoparticles (LN) were prepared via acid precipitation technology. Reactions in a pH range of 4 to 6 were evaluated while preparing the nanoparticles. Lignin nanoparticles were stable at pH 4 to 10. The sizes of the nanoparticles were assessed with dynamic light scattering (DLS); the average diameter of the nanoparticles at pH 4 was 52.7 nm, which was confirmed by SEM. LN has polar centers that can produce an interacting interface with the polymer matrix in which it will be dispersed. The morphologies and structures of combinations of AL and LN were investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis-derivative thermogravimetric (TGA-DTG). The FTIR spectra clearly showed that the positions of the peaks in lignin nanoparticles shifted to slightly lower values due to the interaction between lignin molecules and ethylene glycol.

  • Researchpp 2898-2906Garcia, D., Caraschi, J., Ventorim, G., Vieira, F., and Protásio, T. (2018). "Comparative energy properties of torrefied pellets in relation to pine and elephant grass pellets," BioRes. 13(2), 2898-2906.AbstractArticlePDF

    Torrefaction is a thermal process that improves the energy properties of plant biomass pellets, providing greater biofuel efficiency for gasification technologies, as well as replacing coal in thermoelectric plants. In Brazil, many agroforestry residues can be improved in value through this technological process, transforming them into modern solid biofuels. There are few studies comparing torrefied wood and elephant grass pellets, especially in relation to their energetic characteristics. This study analyzed the high heat value, energy density, ash content, fixed carbon, volatile materials, lignin, holocellulose, extractives, bulk density, and mechanical durability of these pellets. Due to the absence of Brazilian normative standards for these pellets, the international standard ISO 17225 (2014) was used for comparisons. The results revealed substantial differences among the samples, mainly regarding their moisture content, higher heating value, and energy density in torrefied pellets. It was concluded that these torrefied pellets are biofuels having lower water adsorption, higher heating value, and higher energy density than the pine and elephant grass pellets.

  • Researchpp 2907-2915Hamdan, S., Md Rezaur, R., Ismail, J., and Haznizam, A. (2018). "Dynamic Young’s modulus and moisture content of tropical wood species across sap, median, and internal wood regions," BioRes. 13(2), 2907-2915.AbstractArticlePDF

    The dynamic Young’s modulus (Ed) and moisture content (MC) were determined for two tropical wood species, Gymnacranthera eugenifolia and Sindora sp. using the free-free vibration method. The wood species were tested at the sap, median, and internal regions. The dynamic Young’s modulus was found to be linearly correlated to the radial distance, with Ed gradually increasing with respect to the reduction in radial distance to the centre of the wood. Linear correlation was observed between the radial distance and Ed, with Ed gradually decreasing with respect to the radial distance from the centre. For Sindora sp. and Gymnacranthera eugenifolia, Ed ranged from 0.8 to 2.4 GPa and 0.9 to 1.6 GPa, respectively. Moisture content in Sindora sp. displayed a broad range, from 10 to 20 wt.%, while Gymnacranthera eugenifolia displayed a narrower range from 8 to 15 wt.%. Free-free flexural vibration testing is a fast, inexpensive, and reliable method for determining Ed. However, further studies are needed to investigate the acoustic qualities of these woods, such as the speed of sound and damping within the wood.

  • Researchpp 2916-2931Jia, D., and Yi, S. (2018). "Classification of Hoi-An and Sin-Chew agarwood by components analysis of VOCs released in heat-treated agarwood using TD-GCMS and chemometric methods," BioRes. 13(2), 2916-2931.AbstractArticlePDF

    Agarwood can be divided into resinous heartwood from the Hoi-An zone and Sin-Chew zone. Traditionally, an experienced human grader classifies agarwood by odor. However, sensory errors can follow from subjectivity, poor reproducibility, and time consumption during manual work. In this study, agarwood samples were heat-treated to release volatile organic compounds (VOCs), which were analyzed using the thermal desorption – gas chromatograph mass spectrograph (TD-GCMS) method and chemometrics analysis. The classification of agarwood was then identified. Sesquiterpenes and other aromatic compounds were the main compounds of heat-treated VOCs. Twenty-six characteristic compounds were screened via stepwise regression. Fisher discriminant analysis and Bayes discriminant analysis were conducted, based on the 26 compounds, to classify the agarwood samples. Discriminant functions of the two analysis methods were obtained.The results showed that it is feasible to use the TD-GCMS method combined with chemometrics analysis to analyze VOCs from heat-treated agarwood instead of experienced graders to classify the agarwood samples as being from either the Hoi-An zone and Sin-Chew zone. This study also provides a way to classify unknown samples by odor through 26 characteristic compound’srelative peak area and the discriminant equations, offering the possibility of testing an unknown sample’s cultivation region.

  • Researchpp 2932-2944Han, Z., Guo, Z., Zhang, Y., Xiao, X., and Peng, C. (2018). "Potential of pyrolysis for the recovery of heavy metals and bioenergy from contaminated Broussonetia papyrifera biomass," BioRes. 13(2), 2932-2944.AbstractArticlePDF

    Heavy metal contaminated biomass is a severe environmental problem. Presently, the disposal of heavy metal contaminated biomass tends to seek the recovery of both heavy metals and bioenergy. In this study, pyrolysis technology was employed to pyrolyze contaminated biomass to elucidate the influence and fate of the heavy metals and the potential for recovering bioenergy. The results showed that heavy metals in biomass reduced the reaction energy in the main decomposition stage by approximately 10%, while 25% of the biomass decomposed to solid products. Moreover, 63.2% to 68.2% of the Cd and 69.0% to 77.9% of the Cu were retained in the solid, and the metals in the residues existed as metal elements that can be recovered by general smelting. The majority of the biomass (75%) generated volatile products and was only slightly influenced by heavy metals. Compared with the uncontaminated biomass, the component of bioenergy was reduced only slightly, which suggests strong potential for recovering bioenergy. The finding of this paper can be a theoretical foundation to support the responsible disposal, through pyrolysis, of biomass contaminated by heavy metals.

  • Researchpp 2945-2959Wan Mohamed, W., Baharum, A., Ahmad, I., Abdullah, I., and Zakaria, N. (2018). "Effects of fiber size and fiber content on mechanical and physical properties of mengkuang reinforced thermoplastic natural rubber composites," BioRes. 13(2), 2945-2959.AbstractArticlePDF

    Thermoplastic mengkuang composites are an alternative material to solve environmental pollution issues associated with synthetic polymers. Mengkuang, or Pandanus atrocarpus, raw fiber was cut, dried, ground, and sieved to the required size. The fiber was filled into the matrix of natural rubber (NR) and high-density polyethylene (HDPE) by melt blending via internal mixer. The blend of HDPE/NR at 60/40 ratio with fiber sizes of 125 µm, 250 µm, and 500 µm were prepared at fiber contents of 10%, 20%, and 30%. The effects of fiber size and fiber content on the thermoplastic composite were investigated using tensile test, impact test, water absorption, and field emission scanning electron microscopy (FESEM). The maximum tensile strength and tensile modulus were obtained at 20% fiber content of 250 µm fiber size. Impact strength gradually decreased with the increased percentage of fiber content at fiber size, 125 µm and 250 µm. The highest tensile strain at break and lowest water absorption was observed at 10% fiber content for all sizes being studied. The effects of fiber size on water absorption, and percentage of fiber content on impact strength and tensile strain at break were statistically significant (p < 0.05).

  • Researchpp 2960-2976Kong, F., Guo, Y., Liu, Z., Wang, S., and Lucia, L. (2018). "Synthesis of cationic xylan derivatives and application as strengthening agents in papermaking," BioRes. 13(2), 2960-2976.AbstractArticlePDF

    Cationic xylan derivatives were prepared by etherification using 3-chloro-2-hydroxypropyltrimethylammonium chloride as the cationic reagent under an alkaline condition. These derivatives were utilized as strengthening agents to enhance the mechanical strength properties of paper. Cationic xylan derivatives with different degree of substitution (DS) values (0.11 to 0.35) that corresponded to different cationic charge densities (0.51 mmol/g to 0.85 mmol/g) were successfully synthesized, and the reaction parameters were optimized based on the DS and charge density. The cationic xylan derivatives were characterized by means of elemental analysis, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectrometry. The xylan derivatives had a good performance in strengthening the physical properties of the paper, such as the tensile, tear, and burst strengths. When the DS of the cationic xylan derivative was higher, the strengthening effectiveness was better. At a 2.4-wt.% (based on dried pulp) dosage with the xylan derivative that had a DS of 0.32, the tensile, tear, and burst indices of the pulp increased by 63%, 58%, and 42%, respectively. For the pulps with different beating degrees, the cationic xylan derivative was more beneficial to the pulps with a lower beating degree.

  • Researchpp 2977-2995Clare, D., Wang, Z., Cheng, J., and Savithri, D. (2018). "Aminopeptidase modified hydrolytic enzymes to improve the efficiency of sugar production from alkaline pretreated switchgrass," BioRes. 13(2), 2977-2995.AbstractArticlePDF

    Cellulases and β-glucosidases (βGSD) are enzymes commonly used in the biofuel industry. In this study, smaller-sized variants were generated with aminopeptidase such that high catalytic capabilities were retained. Under the defined experimental conditions, the degree of hydrolysis was greater using cellulase substrates, compared to βGSD, based on ortho phthaldialdehyde (OPA) assay data (44% versus 15%). Proteolysis of cellulases was also evident based on sodium dodecyl sulfate polyacrylamide electrophoresis (SDS-PAGE) protein banding patterns seen after peptidase treatment. Residual cellulase activity was retained after peptidase hydrolysis (67% to 73%) based on standard filter paper assays. Peptidase treated cellulases and βGSD were then utilized for hydrolysis of alkaline-pretreated switchgrass (Panicum virgatum). Interestingly, the efficiency of the reaction, defined as milligrams of sugar produced per filter paper unit, was higher using truncated cellulases for bioprocessing reactions (~14%), especially in the absence of sodium azide. Conversely, incubation of βGSD with peptidase revealed minimal proteolysis with low impact on the efficiency of hydrolysis.

  • Researchpp 2996-3004Wang, Q., Wu, N., Li, X., Wang, H., Lei, H., Du, G., Wu, Z., and Liu, S. (2018). "Improving the performance of eucalyptus wood particle board panels with low free formaldehyde emission urea-formaldehyde resin using pectinase enzyme pre-treatments," BioRes. 13(2), 2996-3004.AbstractArticlePDF

    The potential for using the enzyme pectinase as a pre-treatment to improve the properties of eucalyptus particle-based panels was investigated at different pre-treatment times, temperatures, and particle-to-enzyme ratios. As the pre-treatment time was increased from 10 min to 30 min, the free formaldehyde emission content was reduced (P < 0.0001). The pectinase enzyme pre-treatment reduced the pectin content and increased the permeability of treated wood, allowing more free formaldehyde to be released from the panels. The free formaldehyde emission content of all panels was lower than 3.0 mg per 100 g, due to the kind of urea-formaldehyde (UF) resin used. When the pre-treatment time was 30 min and the temperature was 45 °C, the mechanical properties, including modulus of elasticity (MOE), modulus of rupture (MOR), and internal bonding strength (IB), of the resulting panels were the best among all the selected treatment times and temperatures. As the ratio of particles to solution was reduced from 1:100 to 1:80 or 1:60, the mechanical properties of the particle board panels were improved (P < 0.0001). This was attributed to the pectinase enzyme pretreatment changing the surface of the particles, resulting in a better interface between UF resin and particles.

  • Researchpp 3005-3016Xu, W., Li, X., and Shi, J. (2018). "Activation of cellulosic ethanol lignin by laccase and its application as plywood adhesive," BioRes. 13(2), 3005-3016.AbstractArticlePDF

    To reuse biorefinery waste, cellulose ethanol lignin was treated with a laccase system and used as an adhesive for plywood panel preparation. The effects of the amount of laccase, the pH of the reaction system, the reaction temperature, and the reaction time on the bonding strength were studied. The reaction characteristics of the lignin were analyzed by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR). The results showed that the amount of laccase and the pH value of the reaction system had a significant effect on the bonding strength, and the addition of Tween-80 and polymeric diphenylmethane diisocyanate (PMDI) could improve the wet strength of the cemented system. FT-IR indicated that the lignin had been etherified and NMR analysis showed the partial ether bond in the β-O-4 structure was cleaved so that the lignin fragment was involved in the gluing of the small molecules. Microscopically speaking, the SEM analysis did not observe the activation of lignin adhesives infiltrating the wood substrate, indicating a weak mechanical gluing.

  • Researchpp 3017-3029Yu, Y., Guo, Y., Jiang, T., Li, J., Jiang, K., and Zhang, H. (2018). "Study on process and parameter optimization of selective laser sintering of walnut shell composite powder," BioRes. 13(2), 3017-3029.AbstractArticlePDF

    This study aimed to improve the sintering quality of biomass composite powder by using walnut shell and copolyester hot melt adhesive (Co-PES) powders as the main raw materials to prepare the walnut shell/Co-PES composite (WSPC) powder for selective laser sintering (SLS). An orthogonal experimental design of five factors and four levels was adopted to optimize the process parameters for the SLS experiment. Moreover, through range analysis, the influences of laser power, preheating temperature, scanning speed, layer thickness, and scan spacing on the quality of WSPC were also studied. In addition, the synthesis weighted scoring method was used to determine the optimum process parameters. The results showed that the WSPC part quality was optimum when the laser power was 12 W, the scanning speed was 2000 mm/s, layer thickness was 0.15 mm, scan spacing was 0.2 mm, and preheating temperature was 80 °C.

  • Researchpp 3030-3044Feng, Y., Li, J., Wang, B., Tian, X., Chen, K., Zeng, J., Xu, J., and Gao, W. (2018). "Novel nanofibrillated cellulose/chitin whisker hybrid nanocomposites and their use for mechanical performance enhancements," BioRes. 13(2), 3030-3044.AbstractArticlePDF

    The aim of this work was to demonstrate the production potential of a combination of the two materials cellulose nanofibrils (CNF) and chitin nanowhisker (CNW) using wheat straw and chitin. CNF and CNW were prepared from TEMPO-oxidation and acid hydrolysis prior to high-pressure homogenization. The zeta potential results indicated the differences in the suspended mechanism for the CNF and CNW dispersions. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) revealed that the chemical composition and crystal unit changes during the chemical separation process. Hybrid CNF/CNW films were prepared via casting and evaporation. The films had better mechanical properties, which were ascribed to multivalent physical interactions between CNF and CNW. However, increasing the CNW content up to 50% negatively affected the mechanical properties of the hybrid films. In addition, all films showed high transparency and excellent flexibility. These results indicated that the interaction between CNF and CNW effectively enhanced the mechanical performance of films.

  • Researchpp 3045-3060Ismail, M., Sultan, M., Hamdan, A., and Md Shah, A. (2018). "A study on the low velocity impact response of hybrid Kenaf-Kevlar composite laminates through drop test rig technique," BioRes. 13(2), 3045-3060.AbstractArticlePDF

    This paper presents the effects of a low velocity impact test on the hybrid composites of kenaf and Kevlar. In recent years, there has been a trend to replace the synthetic fibers, used as reinforcement in epoxy composites formation, with natural fibers due to their low cost, high flexibility, biodegradability, and recyclability. In order to surpass the low mechanical strength of natural fibres in comparison to the conventional composites, hybrid composites combining both types of fibres was introduced. This combination will lead to improvement in the mechanical strength and biodegradability of epoxy composites, which is important for waste reduction and protection of the environment. The materials were fabricated in a seven-layer laminate configuration utilizing a ratio of 3:1:3 (Kevlar:kenaf:Kevlar) for a hybrid composite. This combination earlier had been found to give the best tensile test performance. An original composite with seven layers of kenaf (full kenaf) and one with seven layers of Kevlar (full Kevlar) were also prepared for comparison. The selected specimens underwent a low velocity impact test with variations in energy. The failure mode was observed. The results showed that a seven layer laminate only withstood an impact energy below 30 Joules, and it failed when the impact energy approached 40 Joules. The hybrid composites approached the quality performance of full Kevlar and exhibited better mechanical properties than full kenaf composites. Therefore, the novel hybrid composites can be used for product development in environmentally friendly technologies.

  • Researchpp 3061-3081Zhen, M., Tang, J., Song, B., and Liu, X. (2018). "Decontamination of methylene blue from aqueous solution by rhamnolipid-modified biochar," BioRes. 13(2), 3061-3081.AbstractArticlePDF

    To remove methylene blue (MB) from water, rhamnolipid-modified biochar (BC-RL) was synthesized via a facile method. The surface structures and properties of the biochar (BC) and BC-RL were characterized by scanning electron microscopy, Fourier transform infrared spectra, X-ray diffraction spectra, X-ray photoelectron spectra, N2 adsorption-desorption isotherms, and Raman spectra. The results showed that modification with rhamnolipid remarkably increased the functional groups on the BC-RL, but reduced the surface area. The MB removal efficiency of the BC-RL increased with an increase in the adsorbent loading and temperature. Moreover, the adsorption performance of the BC-RL was obviously higher than that of the BC, which was mainly attributed to the increased number of functional groups. The adsorption kinetic data was fitted well to the pseudo-second-order model with a coefficient of determination greater than 0.999. The coefficients of determination of the adsorption isotherm fitted by different models decreased in the following order: BET > Freundlich > Langmuir. This indicated that the adsorption of MB onto the BC-RL involves a multilayer formation process. These results suggested that the BC-RL could be an environmentally benign and cost-effective adsorbent for the removal of MB from aqueous solutions.

  • Researchpp 3082-3097Jankowska, A., Boruszewski, P., Drożdżek, M., Rębkowski, B., Kaczmarczyk, A., and Skowrońska, A. (2018). "The role of extractives and wood anatomy in the wettability and free surface energy of hardwoods," BioRes. 13(2), 3082-3097.AbstractArticlePDF

    The main goal of this paper was to clarify to what extent extractives and wood structure determine the surface properties of hardwoods, mainly tropical. The role of wood extractives relative to properties, such as wettability and free surface energy, has been confirmed. The most significant seemed to be cyclohexane extractives. It was further found that in the case of tested tropical wood species, the extractives contents were high. Moreover the important role of axial parenchyma in wood wettability was established. It was established that multiple regression analysis could be useful in understanding wood properties as the result of the complex structure of wood. The obtained data is crucial from a practical point of view for its disclosure of those wood species that require surface modification prior to varnish coating.

  • Researchpp 3098-3109Marková, I., Ladomerský, J., Hroncová, E., and Mračková, E. (2018). "Thermal parameters of beech wood dust," BioRes. 13(2), 3098-3109.AbstractArticlePDF

    Wood as a flammable material can be characterized by fire and technical parameters, such as initial temperatures of its degradation, caloric heat, caloric value, and explosion limits. These parameters reflect the suitability of using a particular type of wood for construction purposes or as biofuel. This article presents selected characteristics of beech wood (Fagus sylvatica L.) particles (dust fractions) on the basis of continual thermal loading. The thermal properties of beech particles were characterized by thermogravimetric analysis (TG), which indicated different thermal degradation patterns for different dust fractions. The beech wood dust consisted mainly of fractions of 80 µm, 32 µm, and < 32 µm, which was 70.50% of the sample. These fractions form explosive mixtures with air, and their thermal degradation involves only one step.

     

  • Researchpp 3110-3124Yin, Y., Han, X., Dang, C., and Pu, J. (2018). "Improved applied quality of fast-growing poplar derived by in-situ formation of itaconic acid-silica sol hybrid polymer within wood hierarchical cell structure," BioRes. 13(2), 3110-3124.AbstractArticlePDF

    Poplar wood (Populus euramericana cv. “I-214”) was impregnated by pulse dipping at 0.7 MPa to 0.8 MPa for 30 min with a catalyst Ln∼SO42−/TiO2–SiO2, itaconic acid, and silica sol. Then, the modifier was cured within the wood micropores during in situ polymerization via kiln drying. The treated wood exhibited increased mechanical strength and decreased hygroscopicity. The modified samples were also characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results from the FTIR analysis indicated that the itaconic acid and SiO2 polymerized with the active groups of the wood cell wall. The TGA revealed that the crosslinking reaction between the modifier and wood enhanced the thermal stability of the composite. Lastly, the SEM results indicated the presence of the good interfacial adhesion in the wood modifier between the wood fibers and polymer.

  • Researchpp 3125-3134Yang, C., Jiang, T., Yu, Y., Dun, G., Ma, Y., and Liu, J. (2018). "Study on surface quality of wood processed by water-jet assisted nanosecond laser," BioRes. 13(2), 3125-3134.AbstractArticlePDF

    Water-jet assisted nanosecond laser process was used to avoid the process defects of traditional nanosecond laser on wood. Korean pine was used as the experimental material. A factorial design of experiment was performed. The influence of cutting speed and laser power on the kerf width was compared with and without the water-jet assisted system. The surface morphology of processed wood kerf was observed via scanning electron microscopy (SEM). The results showed that kerf width increased with increased laser power and decreased with increased cutting speed. When the cutting speed was 50 mm/s and the laser power was 6 W, the minimum value of the kerf width was 0.26 mm with the water-jet assisted system involved, and the surface quality was excellent. The experimental results were processed by analysis of variance and multi-linear regression analysis. Moreover, prediction model of process parameters and kerf width was established, and the prediction model had better prediction accuracy, providing certain theoretical basis for predicting kerf width of wood processed by water-jet assisted nanosecond laser.

  • Researchpp 3135-3143Li, H., Yang, S., Sun, H., and Liu, X. (2018). "Production of activated carbon from cow manure for wastewater treatment," BioRes. 13(2), 3135-3143.AbstractArticlePDF

    This study presents the chemical compositional analysis of cow manure in terms of holocellulose (35.97%), lignin (19.02%), and ash (17.47%). Activated carbons (of specific surface area 114 to 893 m2/g, iodine value 219 to 718 mg/g, methylene blue adsorption value 40.5 to 501 mg/g, and ash 16.17% to 22.3%) were prepared from cow manure by using various activator compounds such as potassium carbonate. The results showed that the activation effect of potassium carbonate and zinc chloride was better under the given conditions. The main ash found in the activated carbons was silica, which was reduced to about 3% by washing with sodium hydroxide solution. The prepared activated carbons were used to treat the wastewater from the cow farm and for the pollutant removal that effectively met the discharge standard requirements. These results indicated that the production of activated carbons from cow manure is a promising method for the cleaner production in intensive dairy farms.

  • Researchpp 3144-3156Awais, M., Gulfraz, M., Asad, M. J., Kabir, F., Khan, K. S., and Naqvi, S. M. Z. A. (2018). "Mesophilic anaerobic co-digestion of cattle manure with Malus domestica and Dalbergia sissoo during biomethane potential assays," BioRes. 13(2) 3144-3156.AbstractArticlePDF

    The burning of cattle manure for domestic use, and plant biomass left out in fields, is a common practice in South Asia, specifically Pakistan. According to the 2014 government of Pakistan (GOP) survey, Pakistan had 171 million head of cattle that would produce 345 billion kg of manure, which could easily be converted into 150 billion m3 of biogas. The focus of the present study was to evaluate the benefits from co-digestion of cattle manure (CM) with Dalbergia sissoo leaves (DSL) and Malus domestica leaves (MDL), with a focus on changes in the biodegradability, C/N ratio effect, and synergistic effect. The idea was to adjust the C/N ratio to increase biodegradability at mesophilic range to help the process to produce more methane than 100% manure-based digestion. First, the ideal pH and temperature conditions for mesophilic anaerobic digestion (AD) were optimized to carry out further co-digestion under the same conditions. The results of co-digestion revealed a 40% (251 NmL CH4/g VS) increase in methane yield by replacing 20% of volatile solid in CM-based AD reactors with MDL. This combination also presented a biodegradability of 59% and a synergistic effect (θ) value of 1.40, which corresponded to highly positive synergism reflecting the optimum growth conditions. The DSL/CM co-digestion also followed the same pattern, and the maximum methane yield of 229 NmL CH4/g VS was obtained using a 20/80 DSL/CM combination.

     

  • Researchpp 3157-3164Yemshanov, D. W., McKenney, D., and Hope, E. S. (2018). "Comparing alternative biomass supply options for Canada: What story do cost curves tell?" BioRes. 13(2), 3157-3164.AbstractArticlePDF

    Policy makers and investors often need to consider trade-offs between alternative biomass-based energy supply options. Supply cost potentials for three bioenergy feedstocks prevalent in Canada including agricultural residues, dedicated woody crops, and forest harvest residues are summarized. Each feedstock has its own particular cost characteristics depending on the quantities involved. Importantly, this synthesis revealed significant differences in the uncertainty associated with the cost estimates, with agricultural residues having the greatest variation, followed by woody crops and postharvest forest residues, respectively. One implication of this uncertainty is that the attractiveness of each feedstock option likely depends on local market demand conditions and producer circumstances, making definitive aggregate supply estimates challenging.

  • Researchpp 3165-3176Chen, C., Sun, K., Wang, A., Wang, S., and Jiang, J. (2018). "Catalytic graphitization of cellulose using nickel as catalyst," BioRes. 13(2), 3165-3176.AbstractArticlePDF

    Microcrystalline cellulose was pyrolyzed and catalytically graphitized under temperatures ranging from 1000 °C to 1600 °C in the presence of nickel (Ni). Optimal conditions for graphitization were determined, along with the structure and conductivity of the resulting samples. The optimal conditions were identified as heating at 1400 °C for 3 h with 3 mmol Ni loading per gram of carbon. The samples obtained had excellent graphitic crystallinity comparable to that of commercial graphite. However, in the absence of Ni loading, no obvious graphitic structure appeared after heating under the same conditions, indicating that Ni was an efficient catalyst for the graphitization of cellulose-based carbon. High-resolution transparent electron microscopy (HRTEM) images showed well-defined graphitic structures of more than 30 layers with slice gaps of 0.340 nm. The conductivities of the samples treated under different temperatures varied from 27 S·cm-1 to 54 S·cm-1 under 20 MPa of pressure, and higher temperatures led to higher conductivity due to better graphitic crystallinity. This study fills an important area of research on the catalytic graphitization of cellulose and provides a reference for the preparation of other cellulose-based graphitic materials.

  • Researchpp 3177-3194Valasek, P., D'Amato, R., Müller, M., and Ruggiero, A. (2018). "Musa textilis cellulose fibres in biocomposites – An investigation of mechanical properties and microstructure," BioRes. 13(2), 3177-3194.AbstractArticlePDF

    The mechanical characteristics of cellulose fibres in biocomposites (epoxy resin/Musa textilis) were investigated relative to the microstructure of these fibres as determined by porosimetry and electron microscopy in terms of their utilization in composite systems. The influence of the chemical treatment via alkali (NaOH) on the change in surface properties and the interfacial interaction of fibres with an epoxy resin was investigated as well as mechanical characteristics of abaca/epoxy composites. The porosity of abaca fibres reached 57% on average, and the averaged tensile strength value was 641 MPa and a Young modulus of 26 MPa. Evaluated composite systems were prepared through a vacuum infusion in which various orientations of long ordered fibres in these composites were evaluated along with the influence of a 6% NaOH chemical treatment on the resultant mechanical properties. The alkali treatment increased the tensile strength of the observed composite systems by up to 16 MPa. The chemical treatment of the abaca fibres led to an increase in the interfacial interaction, which was evaluated with electron microscopy.

  • Researchpp 3195-3207Kim, S., Sung, S. H., Lim, S., and Ahn, K. H. (2018). "Particle dispersion in silica-poly(vinyl alcohol) coatings: Role of particle-polymer interaction," BioRes. 13(2), 3195-3207.AbstractArticlePDF

    Silica nanoparticle (SiNP)-poly(vinyl alcohol) (PVOH) coating is an important material system in paper coating applications, where particle distribution critically affects coating performance. In the present study, the authors investigated a role of physicochemical interaction between SiNP surface and PVOH chain in SiNP distribution in the coating layer, with a comparison of the suspension at pH 3 (good interaction) and pH 10 (poor interaction) as PVOH concentration was varied. Rheological properties and sedimentation behavior of the suspensions showed the dispersion stability of SiNP at pH 3 was improved by the addition of PVOH, whereas it was independent of the PVOH concentration at pH 10. Scanning electron microscopy and small angle x-ray scattering intensity of dried coating layer showed the uniform and dense structure with homogeneous distribution of SiNPs at pH 3, where spatial arrangement of SiNPs depended on the addition of PVOH. However, non-uniform and porous structures with SiNP aggregates were observed at pH 10, where the spatial arrangement of SiNPs was independent to the addition of PVOH. The stress development during drying of the coating suggested that the mechanical property was related to the spatial arrangement of individual SiNPs at pH 3, whereas to the distribution of SiNPs aggregates at pH 10.

  • Reviewpp to be addedZhang, S., Chen, C., Duan, C., Hu, H., Li, H., Li, J., Liu, Y., Ma, X., Stavik, J., and Ni, Y. (2018). "Regenerated cellulose by the Lyocell process, a brief review of the process and properties," BioRes. 13(2). Page numbers to be added.AbstractArticlePDF

    Lyocell fiber has emerged as an important class of regenerated cellulose that is produced based on the N-methyl morpholine-N-oxide (NMMO) dissolution method, and it has unique properties compared to viscose fiber. The NMMO technology provides a simple, resource-conserving, and environmentally friendly method for producing regenerated cellulose fiber. In this paper, the manufacturing process, environmental impact, and product quality of lyocell fiber are reviewed and compared with those of the conventional viscose fiber.

  • Researchpp 3208-3218Lian, Y., Zhang, J., Li, N., and Ping, Q. (2018). "Preparation of hemicellulose-based hydrogel and its application as an adsorbent towards heavy metal ions," BioRes. 13(2), 3208-3218.AbstractArticlePDF

    Water contamination by heavy metal ions is a worldwide problem. In this work, a type of hydrogel, based on hemicellulose, was prepared via graft copolymerization. The reaction time and cost were reduced by modifying the traditional preparation process. The hemicellulose-based hydrogel was an opaque, smooth, well-distributed, and high resilience hydrogel. To better understand the application of hemicellulose-based hydrogel as an absorbent for the removal of Pb(II) (lead nitrate) from heavy metal contaminated water, the hydrogel was used to adsorb Pb(II) from aqueous solution. The various factors that influenced the Pb(II) removal efficiency were studied, including concentration and temperature. The results showed that the hemicellulose-based hydrogel was assessed as an ideal absorbent towards Pb(II), showing maximum monolayer adsorption capacity of 5.88 mg/g. The Pb(II) adsorption isotherm was determined to further understand the adsorption mechanism. The results demonstrated that the adsorption of the hemicellulose-based hydrogel on Pb(II) belongs to the monolayer adsorption and that adsorption conforms to the Langmuir model better than the other model. It revealed that the adsorption process of Pb(II) on hemicellulose-based hydrogel was spontaneous and endothermic in nature. The hemicellulose-based hydrogel was proven as a good material for potential application.

  • Researchpp 3219-3235Yu, C., Zhang, W., Bekele, L., Lu, X., Duns, G., Jin, L., Jia, Q., and Chen, J. (2018). "Characterization of thermoplastic composites developed with wheat straw and enzymatic-hydrolysis lignin," BioRes. 13(2), 3219-3235.AbstractArticlePDF

    Novel thermoplastic composites filled with wheat straw (WS) and enzymatic-hydrolysis lignin (EHL) were developed and characterized. The three-dimensional melt blending system of WS, EHL, and high-density polyethylene (HDPE) was optimized via orthogonal experiments. The mechanical properties and melt index of the composites were measured and the optimum ratio of the composites was determined. Based on the optimum ratio of the composites’ blending system, identified through compounding granulation and extrusion molding process links, pilot products of the composites were produced. The thermal behavior, polar groups, and surface structures of the fibers and developed thermoplastic composites were assessed by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) analysis, respectively. The addition of EHL, an abundant renewable resource, improved the dispersity of the matrix as well as the mechanical and thermal properties of the composites. The results provide a theoretical basis for the application and development of new composites and illustrate a potential industrial application of EHL.

  • Researchpp 3236-3249Borz, S. A., Talagai, N., Cheţa, M., Gavilanes Montoya, A. V., and Castillo Vizuete, D. D. (2018). "Automating data collection in motor-manual time and motion studies implemented in a willow short rotation coppice," BioRes. 13(2), 3236-3249.AbstractArticlePDF

    Time and motion studies are often used to evaluate the performance of various product systems. However, traditional studies are characterized by a series of technical limitations, and they require many resources. This study tested the capability of a low-cost Global Positioning System (GPS) receiver and an accelerometer unit to automate the field data collection for characterizing motor-manual felling of willow short rotation coppices. The results were promising. By thresholding the acceleration data, the running and stopped engine states were accurately separated. Also, by combining the GPS speed with the acceleration data, followed by threshold setting and data visualization in the Geographic Information System software, detailed time categories, such as productive, working, and non-working times, could be separated. The methods described herein could be used to manage long-term field data collection, as such operations are affected by many operational factors.

  • Researchpp 3250-3258Guo, Y., Li, D., Zhu, S., and Chen, Y. (2018). "Interaction of low cycle fatigue and creep in biomass-filled plastic composites," BioRes. 13(2), 3250-3258.AbstractArticlePDF

    Most research on biomass-filled plastic composites (BFPCs) mainly focuses on their formulation and physical/mechanical properties, but studies on the connection performance of BFPCs are very rare. However, such performance is vital in the quality assessment of BFPCs products and plays an important role in improving product quality and promoting its application in the field of architecture and furniture. Therefore, the behavior of L-type BFPCs structure under the interaction of fatigue-creep was investigated. Results suggested that the fatigue-creep curve is a typically three-region curve at 80% and 60% failure load, and only first two stages at 40% failure load. But the damage caused by fatigue-creep interaction was not a simple superposition. Fatigue damage dominated when the holding time was short, and creep damage occupied a dominant position gradually when the holding time was longer. In addition, the lifespan of the BFPC component increased initially and then decreased as holding time increased. The component joint exhibited the least integrated damage when the holding time was 60 s and the lifespan was longer.

  • Researchpp 3259-3274Saoud, K. M., Saeed, S., Al Soubaihi, R., Samara, A., Ibala, I., El Ladki, D., and Ezzeldeen, O. (2018). "Application of Mg(OH)2 nanosheets for conservation and restoration of precious documents and cultural archives," BioRes. 13(2), 3259-3274.AbstractArticlePDF

    Magnesium hydroxide (Mg(OH)2) nanosheets were explored as an effective material for the restoration and conservation of paper-based cultural archives and compared with the commonly used Ca(OH)2 nanoparticles. The (Mg(OH)2) nanosheets were applied to filter paper as a reference, as well as to new and old paper samples. The effectiveness of Mg(OH)2 nanosheets was evaluated by (i) a pH test of the surface and the bulk extracts, (ii) measuring the alkaline reserve and correlating it with the enhancement in life expectancy, and (iii) in terms of mechanical strength. The alkaline reserve test indicated an increase in the alkaline buffer, which resulted in markedly reduced acidic content of the samples. It was inferred from the improved properties that Mg(OH)2 nanosheets coated the paper as a lamination sheet and protected it as the first line of defense against acidic environmental attack. Moreover, its presence within the paper acted as an alkaline reserve and also as reinforcement in the form of an inorganic nanosheet. The results suggest that the nanosheets are an innovative, compatible, and efficient material for the consolidation and restoration of old and new paper samples.

  • Researchpp 3275-3283Pan, L., Li, P., Tao, Y., & Guo, H. (2018). "Antimicrobial agent effectiveness in fish glue prepared by heat treatment and enzymatic hydrolysis of swim bladders," BioRes. 13(2), 3275-3283.AbstractArticlePDF

    Fish glue prepared from swim bladders has been used in China to glue wooden parts together since ancient times. It is also used as an important natural glue for wooden artifact and building restoration, musical instrument fabrication, as well as many other fields. Microorganism contamination is a major concern for fish glue preservation. In this research, fish glue was prepared from swim bladders using two methods, namely, heat treatment and enzymatic hydrolysis. Then, the molds that germinated in both samples were analyzed. Light microscope and scanning electron microscopy (SEM) observations of the molds’ hypha morphology identified Alternaria in both glue samples. The antimicrobial efficiencies of borax, sodium diacetate, and Antim AL-D (an organic/inorganic composite antimicrobial) were then compared. The results demonstrated that all antimicrobial agents in the research effectively inhibited Alternaria germination in both fish glue samples. A 0.3% (by weight) solution of Antim AL-D was sufficient for preserving fish glue. As for borax and sodium diacetate, the addition of a minimum of 1.0% was adequate to inhibit Alternaria growth. Results also revealed that the addition of Antim AL-D minimally affected the shear strength of glued wooden parts.

  • Researchpp 3284-3299Hu, Z., Zhang, G., Chen, Y., Wang, Y., He, Y., Peng, L., and Wang, L. (2018). "Determination of lignin monomer contents in rice straw using visible and near-infrared reflectance spectroscopy," BioRes. 13(2), 3284-3299.AbstractPDF

    Genetic modification of plant lignin composition is an important strategy for improving biomass enzymatic digestibility without sacrificing the normal growth of the plant. However, the absence of fast and convenient methods for rapid determination of lignin composition has impeded corresponding research. Near-infrared reflectance spectroscopy (NIRS) analysis has potential as a solution for this dilemma, while the NIRS measurement for expediently assaying lignin composition in rice straws is still lacking. In this study, visible and near-infrared reflectance spectroscopy (VIS/NIRS) and modified partial least squares (MPLS) method were combined to develop calibration models for predicting the lignin monomer contents in a diverse rice population. Four optimal equations for predicting the content of p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) lignin units and their total amount (H + S + G) were generated with acceptable determination coefficients for calibration (0.85 to 0.93), cross-validation (0.75 to 0.88), and external validation (0.82 to 0.88), and the ratio performance deviation (RPD, 2 to 3.01). This study was the first to demonstrate that VIS/NIRS could give a sufficiently accurate prediction of lignin monomer contents in rice and could be applied for rapid assessments of large-scale rice straw samples.

  • Researchpp 3300-3314Shao, D., Xu, M., Cai, L., and Shi, S. (2018). "Fabrication of wood fiber-rubber composites with reclaimed rubber," BioRes. 13(2), 3300-3314.AbstractPDF

    This research investigated the use of reclaimed rubber (RR) from waste tires to partially replace the rubber compound (RC) when making wood fiber-rubber composites (WRCs). Ninety panels of WRC containing RR were manufactured with RR contents of 0% to 40%, mixing times of 6 min to 14 min, and vulcanizing temperatures of 150 °C to 170 °C. There were three steps, which were the fiber-rubber mixing, tabletting, and vulcanization molding processes. Four regression equations for the tensile strength, elongation at break, hardness, and rebound resilience as functions of the RR content, mixing time, and vulcanizing temperature were derived, and a nonlinear programming model was developed to obtain the optimum panel properties. It was found that when the RR content was within 20%, the wood fibers were well encapsulated and embedded in the RC/RR blends, and the processability of the WRCs were improved by adding RR. The incorporation of RR into the WRCs increased the average tensile strength and hardness by 33.9% and 2.3%, respectively, while the swelling ratio in toluene and 24-h water absorption were reduced by 13% and 42%, respectively.

  • Researchpp 3315-3334Song, W., Zhu, M., and Zhang, S. (2018). "Comparison of the properties of fiberboard composites with bamboo green, wood, or their combination as the fibrous raw material," BioRes. 13(2), 3315-3334.AbstractPDF

    The potential of bamboo green (B), an abundant lignocellulosic residue from the bamboo processing industry, was evaluated to serve as an alternative fibrous raw material in the production of fiberboard. Urea-formaldehyde resin-bonded fiberboards were prepared from B, wood fiber (W), and a mixture of the two (BW). The board type depended on the mass fraction of B in fibrous raw materials (including B and W), which were 0%, 20%, 40%, 60%, 80%, and 100%. The analytical methods used to characterize fibers and fiberboards included X-ray diffraction, thermogravimetric analysis, dynamic mechanical analysis, contact angle analysis, physical-mechanical analysis, and scanning electron microscopy. Compared with W, B showed a higher crystallinity index and thermogravimetric stability, but lower surface hydrophilicity and weaker interactions with urea-formaldehyde resin. Compared with W fiberboards, B fiberboards possessed a lower interfacial adhesion but fibrous raw materials in B fiberboards were better dispersed; moreover, B fiberboard displayed a higher dynamic viscosity, thermogravimetric stability, surface wettability, water absorption, and flexural modulus, but lower thickness swelling and flexural strength. The fiberboards produced with BW had better performances than the fiberboards produced with B and W. The 40% B mass fraction resulted in BW fiberboards with the best physical-mechanical properties.

  • Researchpp 3335-3345Uetimane Jr., E., Jebrane, M., Terziev, N., and Daniel, G. (2018). "Comparative wood anatomy and chemical composition of Millettia mossambicensis and Millettia stuhlmannii from Mozambique," BioRes. 13(2), 3335-3345.AbstractPDF

    The wood anatomy and chemistry of a relatively lesser used wood species, known in Mozambique as nsangala (Millettia mossambicensis J. B. Gillett), was compared to overexploited species jambire (Milletia stuhlmannii Taub.) to provide diagnostic features for safe discrimination. The anatomical results showed that both species shared several similarities such as intervessel pitting size range (8 µm to 11 µm), rays composed of only procumbent cells, fiber dimensions (average length up to 1359 µm and wall thickness up to 10 µm), and banded axial parenchyma. The extractives and lignin content were higher in jambire, while the carbohydrates and acetyl contents were higher in nsangala. The main anatomical feature separating the two species was the porosity pattern with semi-ring porous wood of nsangala compared to the diffuse-porous structure of jambire. Jambire had wider vessel lumina (200 µm) and up to 3 vessels/mm2 compared to nsangala vessel lumina of 86 µm and a frequency of 37 vessels/mm2.

  • Researchpp 3346-3361Huang, X., de Hoop, C., Peng, X., Xie, J., Qi, J., Jiang, Y., Xiao, H., and Nie, S. (2018). "Thermal stability analysis of polyurethane foams made from microwave liquefaction bio-polyols with and without solid residue," BioRes. 13(2), 3346-3361.AbstractPDF

    The thermal stabilities of bio-based polyurethane (PU) foams made from liquefaction bio-polyols with and without solid residue were analyzed by thermogravimetric analysis (TGA) and Fourier transform infrared spectrometry (FTIR). Yaupon holly (Ilex vomitoria) was subjected to microwave liquefaction at different reaction temperatures to characterize the variations of bio-polyol and solid residue with temperature. The results indicated that the solid residue decreased when the temperature increased from 120 °C to 160 °C, while it increased slightly when further increasing temperature to 200 °C. The hydroxyl number decreased with increased reaction temperature. The TGA of PU foams demonstrated that the use of liquefaction bio-polyol with and without solid residue to produce PU foam increased the thermal stability of biofoams as compared with petro-based foam. Moreover, the presence of solid residue in bio-polyol enhanced the thermal stability of biofoams. The FTIR analysis of PU foams suggested that the solid residue had a negative effect on the formation of urethane bonds.

  • Researchpp 3362-3376Jiang, L., He, C., Fu, J., and Li, X. (2018). "Wear behavior of alkali-treated sorghum straw fiber reinforced polyvinyl chloride composites in corrosive water conditions," BioRes. 13(2), 3362-3376.AbstractPDF

    The application of wood-plastic composites is growing rapidly in the fields of corrosion and aging. The present study investigated the effect of alkali-treated (with NaOH concentrations of 0.5, 2.5, 4.5, and 6.5%) sorghum straw (SS) fiber on the wear resistance of polyvinyl chloride (PVC) composites under simulated seawater and acid rain conditions. The results showed that the wear resistance of the SS/PVC composites was noticeably improved by the addition of the alkali-treated SS fiber. SS fiber treated with 4.5% NaOH showed low polarity and hydrophilicity with high crystallinity and improved mechanical properties, which endowed the SS/PVC composites with high interfacial bonding and wear resistance. Exposure to simulated seawater and acid rain resulted in the deterioration of physical (including water repellency and hardness), mechanical, thermal, and wear-resistance properties of the composites; the wear mechanism of the SS/PVC composites after corrosion for 12 days was mainly abrasive wear.

  • Researchpp 3377-3385Lima Jr, M. P., Biazzon, J. C., De Araujo, V. A., Munis, R. A., Martins, J. C., Cortez-Barbosa, J., Gava, M., Valarelli, I. D., and Morales, E. A. M. (2018). "Mechanical properties evaluation of Eucalyptus grandis wood at three different heights by impulse excitation technique (IET)," BioRes. 13(2), 3377-3385.AbstractArticlePDF

    Wood is a natural material with great variability in its mechanical properties. This study analyzed the effectiveness of the impulse excitation technique (IET) to characterize the stiffness of 10-year-old Eucalyptus grandis wood at three different heights of 3 m, 6 m, and 9 m from the bottom (height A, B, and C, respectively). A nondestructive testing method—excitation impulse, using Sonelastic® PC-based technology—and a destructive static bending test were used. The mean value for the modulus of elasticity (MOE) in bending was 16.4 GPa and in IET the value was 16.6 GPa. The average values for MOE in static bending were 14.8 GPa at height A, 17.9 GPa at height B, and 17.0 GPa at height C, demonstrating that the greater the height in the trunk of the tree the greater its modulus of elasticity. The correlation equation between static MOE and dynamic MOE was MOESTAT = 0.743.MOEDYN + 4.0983, with the coefficient of determination of R² = 0.85.

  • Researchpp 3386-3394Zhang, Y., Liu, J., and Su, Y. (2018). "Effect of silica gel in causticized calcium carbonate from nonwood pulping on the AKD sizing efficiency of paper," BioRes. 13(2), 3386-3394.AbstractArticlePDF

    The application of causticized calcium carbonate (CCC) from nonwood pulping as a filler in papermaking is restricted by a marked decrease in alkyl ketene dimer (AKD) sizing efficiency. But the reason for this adverse effect has not been clear. In this paper, effect of carbonization on the AKD sizing efficiency was investigated systematically. The results showed that the hydrated calcium silicate (C-S-H) in the original CCC had been converted into silica gel after carbonization, and this caused the carbonized CCC to have a higher specific surface area and larger pore volume. This could explain the reason why the CCC had a worse AKD sizing efficiency than the conventional CaCO3 fillers. In addition, the effect of pH value of carbonization on the AKD sizing efficiency was also studied. It was discovered that the silica gel generated and the AKD sizing efficiency started to decline dramatically at the pH value of 8.5. Based on the research above, it can be included that pH value of 8.5 is an appropriate pH of carbonization end to maintain the AKD sizing efficiency at a good level.

  • Researchpp 3395-3403Yildirim, N. (2018). "Performance comparison of bio-based thermal insulation foam board with petroleum-based foam boards on the market," BioRes. 13(2), 3395-3403.AbstractArticlePDF

    A process is described for developing bio-based foam board using state of the art freeze-casting technology. The bio-based thermal insulation foam board was produced starting from wood-based cellulose nanomaterials (CNs) water suspensions. Its performance properties were compared to the current products on the market: Foamular® 150 (F150), Styrofoam™ brand square edge insulation (SF), and GreenGuard® XPS (GG). The bio-based foam board’s density was 0.1 g/cm3 with an 8.16% coefficient of variation (CV), which was higher than F150’s density (0.03 g/cm3 with 0.35% CV), SF’s density (0.04 g/cm3 with 3.79% CV), and GG’s density (0.04 g/cm3 with 0.03% CV). The insulation value (R-value) was determined as 3.14 (1.47% CV) for bio-based thermal insulation foam board, 4.37 (0.39%) for F150, 4.43 (0.39%) for GG, and 5.59 (1.55%) for SF. The mechanical performance of the bio-based thermal insulation foam board was lower than those of the current products on the market, so that it requires further enhancement before potential commercialization. However, being among the first nanocellulose thermal insulation foam boards currently available, it still has great potential for use in building systems.

  • Researchpp 3404-3410Deus, P., Alves, M., Vieira, F., and Bilesky, L. (2018). "Analysis of the cutting parameters in front milling for medium density fiberboard," BioRes. 13(2), 3404-3410.AbstractArticlePDF

    Medium density fiberboard (MDF) is an industrial product manufactured from lignocellulosic fibers. It has homogeneity, dimensional stability, and mechanical strength compared with solid wood. Milling is a machining method widely used in the furniture industry; despite the relevance of the subject, there are few works dealing with the specific MDF milling process using computerized numerical control (CNC) machines. This study evaluated MDF milling in CNC machining centers by analyzing roughness. The MDF panels were front direction with the machined cut depth of 3 mm with six replicates, four cutting speeds of 804 m/min, 603 m/min, 402 m/min, and 201 m/min, and one forward speed of 4 m/min. The parameter of roughness average (Ra) was analyzed. The results showed that the surface roughness showed lower values for the cutting speeds of 603 m/min and 804 m/min, and cutting depths of 3 mm exhibited satisfactory results for the front surface. In conclusion, the parameters studied here significantly influence the finish, resulting in uneven surfaces that can reduce the quality of products.

  • Researchpp 3411-3419Makarenko, N. V., Zemnukhova, L. A., Nemtarev, A. V., Kovekhova, A. V., and Arefieva, O. D. (2018). "Composition and structure of phytic acid derivatives from rice bran," BioRes. 13(2), 3411-3419.AbstractArticlePDF
    A novel phosphorus-containing product extracted from rice bran, a rice production by-product from the Far Eastern selection, was isolated. Its composition and structure were determined by chemical methods and IR (Infrared), NMR (Nuclear Magnetic Resonance) (1H, 13C, 31P) spectroscopy, and X-ray phase analysis. Physicochemical characteristics such as moisture, bulk density, pH of the aqueous suspension, and water solubility under different conditions of the phosphorus-containing product were obtained.
  • Researchpp 3420-3428Xiong, K., Pang, Z., Wang, B., Ji, X., Liu, Y., Yang, G., Dong, C., Chen, J., and Lucia, L. (2018). "Biomechanical pulping of poplar with crude enzyme secreted from Trametes sp. lg-9," BioRes. 13(2), 3420-3428.AbstractArticlePDF

    Crude enzyme secreted from Trametes sp. lg-9 was applied in bio-mechanical pulping of poplar. The Canadian Standard Freeness (CSF) of the pulp pretreated with crude enzyme by a charge of 8 IU g-1 pulp was 215 mL. However, the CSF of untreated pulp was 235 mL at the same refining revolutions of 15,000. Also, the energy consumption during refining was significantly lowered. The brightness of enzyme-pretreated pulp was increased by 2%, and the light absorption coefficient and opacity were decreased slightly. The effect of H2O2 (P) and CH3COOOH-H2O2 (PaP) bleaching were reinforced, and the brightness of pulp was further enhanced when the dosage of crude enzyme was great than 8 IU g-1 pulp. However, the content of fines was decreased, and the lowest value was 6.99% when the dosage of crude enzyme was 8 IU g-1 pulp. The results of this work will be valuable for future possible commercialization.

  • Researchpp 3429-3446Liu, Z., Niu, W., Chu, H., Zhou, T., and Niu, Z. (2018). "Effect of the carbonization temperature on the properties of biochar produced from the pyrolysis of crop residues," BioRes. 13(2), 3429-3446.AbstractArticlePDF

    Biochar, a carbon-rich product, can be obtained from crop residues via pyrolysis. Its properties may vary widely depending upon the pyrolysis conditions and feedstock type. Physicochemical properties were studied for biochars produced from rice straw, wheat straw, corn stover, rape stalk, and cotton stalk pyrolyzed at 300 °C to 700 °C. At higher pyrolysis temperatures, the carbon content, pH, and electrical conductivity of the biochars slightly increased, while the O/C and H/C ratios decreased. The pH values had a strong negative linear correlation with the H/C ratio. Higher carbonization temperatures resulted in larger pores and increased the aromatic/aliphatic carbon ratio in the biochars. The oxygen functional groups in the biochars, such as -COOH and -OH, decreased with an increasing carbonization temperature. The combustion performance of the biochars varied with the carbonization temperature because of the differences in the physicochemical compositions of the biochars. Additionally, the crop residue types also influenced the physicochemical properties. The cotton stalk biochar had the highest fixed carbon content and lowest H/C ratio, and thus can be used as a solid biofuel. The rice straw biochar, which had the highest N and O contents, may be a potential soil amendment.

  • Researchpp 3447-3461Xia, T., Sun, E., Tang, W., Huang, H., Wu, G., and Jin, X. (2018). "Structural and thermal stability changes of rice straw fibers during anaerobic digestion," BioRes. 13(2), 3447-3461.AbstractArticlePDF

    Rice straw fibers are potential raw materials that can be used to produce biogas and reinforcing fibers for composites. In order to ascertain the effects of anaerobic digestion on the structural properties of the fibers, the structure of fibrous residuals with different digestion time, including 0, 10, 20, and 30 days, were investigated. The normalized biogas production volume was 224 mL/g volatile solid of substrate, of which the methane content was about 50%. Fiber detergent analyses of the straw before and after 10 days digestion indicated that the cellulose levels increased from 34.3% to 41.3%, and cellulose crystallinity index ranged from 44.9% to 49.9%, respectively. After the rice straw had been digested for 30 days, the cellulose and hemicelluloses of the rice straw were partially degraded; the crystallinity index of the cellulose decreased from 44.9% to 40.1% based on XRD analyses, and the amount of hydroxyl groups were observed to decrease based on FT-IR analyses. Consequently, the polarity and hygroscopicity of the rice straw fibers were speculated to be lowered based on these observed changes. Furthermore, the relative amount of lignin in the straw residuals increased as digestion time increased, which increased the thermal stability of the resulting fibers. As a result of anaerobic digestion, the properties of the rice straw fibers for their use in plastic composites were enhanced.

  • Researchpp 3462-3472Fan, H., Song, H., Wang, X., Gao, D., Zhu, G., Qi, Y., and Liu, J. (2018). "Effect of the formulation control agent on brightness of modified fly ash and its potential application in papermaking," BioRes. 13(2), 3462-3472.AbstractArticlePDF

    Different agents were used to control the crystalline morphology of calcium carbonate on the surface of fly ash, which was then used as a papermaking filler in an attempt to improve the utilization rate of fly ash and reduce the dust pollution problem. A mixed solution of calcium hydroxide and fly ash was used as the raw materials, and then three crystal form control agents were tested: (NaPO3)6, ZnCl2, and Na2B4O7·10H2O. A certain amount of carbon dioxide was bubbled into the mixture to form a precipitated calcium carbonate deposit on the surface of fly ash. The calcium carbonate on the fly ash surface was altered by changing the amount of crystal form control agent to determine the best coating effect. The results showed that at the 0.35% ZnCl2 dosage (relative to the theoretical quantity of the calcium carbonate), the surface of the fly ash was uniformly coated with a layer of spherical calcium carbonate crystals and there was a good coating effect. The highest fly ash brightness obtained was 65.3% ISO, and when this fly ash was used as a paper filler, the paper brightness was 75.6% ISO. More importantly, this study demonstrated the potential of fly ash in papermaking.

  • Researchpp 3473-3486Kržišnik, D., Lesar, B., Thaler, N., and Humar, M. (2018). "Performance of bark beetle damaged Norway spruce wood against water and fungal decay," BioRes. 13(2), 3473-3486.AbstractArticlePDF

    Norway spruce is one of the most important wood species in Central Europe. Unfortunately, bark beetles have prominently attacked spruce trees. Bark beetles colonize wood in symbiosis with ophiostomatoid fungi, which is visible in prominent blue staining. This reduces the commercial value of the infested wood. The relevant properties of blue stained wood were therefore determined: bending and compression strength, sorption properties, DVS analysis, water uptake, and durability against wood decay fungi. This information was applied in the Meyer-Veltrup model for assessment of material resistance. Scanning electron microscopy analysis confirmed severe infestation of blue stained wood, which was also evident from the color of the specimens. The mechanical properties were almost unaffected, as were the sorption properties. However, the durability and water exclusion efficacy of blue stained wood were considerably decreased, which indicates that decay can be expected to appear faster on blue stained wood than on control-untreated wood specimens.

  • Researchpp 3487-3499Li, H., Chen, M. L., Lv, H. F., Yang, F., Yu, L. L., Fei, B. H., and Ma, X. X. (2018). "Effects of guanylurea phosphate treatment on the performance of decorative bamboo filament," BioRes. 13(2), 3487-3499.AbstractArticlePDF

    Decorative bamboo filament is a new material made with bamboo filament by weaving or adhesive. When it is used in indoor wall and ceiling decorations, the fire resistance of the decorative bamboo filament is very important. Guanylurea phosphate (GUP) flame retardants were used in this study to treat decorative bamboo filament. The microstructures before and after the flame retardant treatment were observed by environmental scanning electron microscopy. The effects on the heat release and smoke release were also evaluated with cone calorimetry. The resistance to mildew was tested before and after the modification. The results showed that the GUP fire retardants had good deposition in parenchyma cells. The treated samples containing 25% GUP effectively reduced the heat and smoke release. The peak value of heat release rate (PKHRR) and the total heat release (THR) in 115 s was respectively reduced by 44.9% and 42.2%; the peak value of smoke release rate (PKSPR), the total smoke production (TSP), and the specific extinction area (SEA) of treated decorative bamboo filament was respectively reduced 67.4%, 95%, and 94.4%. The prevention of mildew was slightly enhanced. The prevention rate of Trichoderma viride even reached 100%.

  • Researchpp 3500-3510Huang, C., Zhao, Y., Liu, Y., Chen, Y., Li, C., and Li, Z. (2018). "Surface characterization of plasma-treated eucalyptus alkaline peroxide mechanical pulp using electronic spectroscopy chemical analysis and atomic force microscopy," BioRes. 13(2), 3500-3510.AbstractArticlePDF

    Eucalyptus alkaline peroxide mechanical pulp (APMP) fibers were modified by a low-temperature plasma (LTP) treatment within an air and oxygen mixture. An atomic force microscope (AFM) and electronic spectroscopy chemical analysis (ESCA) were used to analyze the morphological and chemical information of eucalyptus APMP fibers. According to the AFM results, LTP treatment etched the fibers’ surface, allowing for the removal of hydrophobic substances from the surface. According to the ESCA, the oxygen to carbon ratio of the APMP fiber surface increased from 50.08% to 55.47%, and the C1 peak area decreased from 8.89% to 8.45% after a LTP treatment. All of these results indicate that a LTP treatment can modify the APMP fibers and reduce the contents of lignin and extractives, thus exposing more carbohydrate.

  • Researchpp 3511-3524Wang, Z., Zhu, C., Yi, M., Wang, S., Yang, Z., and Feng, Q. (2018). "Analysis of the differences in the microbial community and structure of calcified ONP granular sludge and bagasse granular sludge," BioRes. 13(2), 3511-3524.AbstractArticlePDF

    Anaerobic biological technology has been widely used in the treatment of high-concentration organic wastewater such as old newspaper (ONP) pulping wastewater and bagasse spray washing wastewater before pulping. However, due to the high calcium content and complex chemical properties of the ONP pulping wastewater, granular sludge calcification occurs during the anaerobic treatment, which has negative effects. In contrast, calcification does not occur in the bagasse spray washing wastewater. Therefore, a comparative analysis of the biological flora and structure of the granular sludge for these two types of wastewater can provide theoretical and data support for revealing the cause of calcification of granular sludge. The results indicate a considerable difference between the anaerobic granular sludge for the treatment of bagasse spraying wastewater (B-GS) and the treatment of ONP pulping wastewater (P-GS). The microorganisms in the B-GS were mainly Bactericides (25.4%), Proteobacteria (20.2%), Hyd2412 (14.4%), Chloroflexi (10.6%), and Firmicutes (8.9%). The microorganisms in the P-GS were mainly Bacteroidetes (20.4%), Chloroflexi (19.5%), Proteobacteria (19.3%), Firmicutes (6.2%), Spirochaetae (4.8%), Actinobacteria (4.4%), and Lentisphaerae (4.3%). Methanomassiliicoccus were detected only in the P-GS. The methanogens had a higher relative abundance in the P-GS (50%), and only a small fraction (10%) of methanogens was detected in the B-GS.

  • Researchpp 3525-3544Raabe, J., dos Santos, L., Del Menezzi, C., and Tonoli, G. (2018). "Effect of nano-silica deposition on cellulose fibers on the initial hydration of the Portland cement," BioRes. 13(2), 3525-3544.AbstractArticlePDF
    The surface modification of cellulose fibers was studied, and its influence on the initial hydration of fiber-cement mixtures was evaluated. The fiber modification was conducted through deposition of nano-silica on their surface via the sol-gel method. The fibers were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and the Brunauer-Emmett-Teller method to determine their porosity and specific surface area. The inhibition index (II) was determined in order to evaluate the effect of fibers at the initial hydration of the Portland cement. Modified fibers (MF) presented a homogeneous surface coating formed by spherical nano-silica. The crystallinity index of the fibers was reduced 15% and the specific surface area, volume, and pore diameter increased 209%, 134%, and 10%, respectively, after modification. Regarding the initial hydration, the results showed that the nano-silica present on the surface of the MF slightly accelerated the process of hardening and did not inhibit the hydration of the cement paste (without limestone and additives). The inhibition index of the composites was impaired when limestone (30%) and additives (2%) were added as partial replacement of cement, as well as when the water:cement ratio increased, retarding the initial hydration of the cement.
  • Researchpp 3545-3553Fan, S., Mahmoud, M., Wen, B., Su, Z., and Zhang, Y. (2018). "Bioelectric activity of microbial fuel cell during treatment of old corrugated containerboard discharges," BioRes. 13(2), 3545-3553.AbstractArticlePDF

    The bioelectric activity of two lab scale microbial fuel cell (MFC) designs, MFCI (1,500 cm3) and MFCII (12,000 cm3) were examined using old corrugated containerboard (OCC) discharge for simultaneous effective treatment with greater power production. The decrease of MFC internal resistance (MFC-Rin) resulted in increased generated power output. The different parameters used in MFC included electrode conducting area (ECA), cathodic redox solution (CRS), MFC volume capacity, and MFCs connections. The generated current densities (CD) and power densities output (PD) at variables of external resistances (Rex) that ranged from 10 Ω to 20,000 Ω were calculated to estimate the MFC-Rin. In MFCI, using potassium ferri-cyanide as CRS, the change of ECA from 16 cm2 to 64 cm2 decreased the MFCI-Rin from 130 Ω to 110 Ω, and it was further decreased to 65 Ω when manganese dioxide was used as the CRS. Using Rex 100 Ω, MFCII exhibited lower Rin 18.46%, enhanced voltage 37.5%, and greater chemical oxygen demand removal 4.77% compared with MFCI. Series and parallel connections between four MFCI increased the generated PD by 286% and 258%, respectively, compared with that obtained by single MFCI.

  • Researchpp 3554-3570Li, S., Chen, F., Lin, F., Kong, Y., and Dai, H. (2018). "Adsorption performance of SiO2/CPAM composites for aqueous Ca(II)," BioRes. 13(2), 3554-3570.AbstractArticlePDF

    Silica/cationic polyacrylamide (SiO2/CPAM) composites with a dendritic structure were prepared via in situ polymerization based on silica containing vinyl groups and acrylamide monomers. The structure and surface properties of the composites were revealed with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transformed infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The adsorption behavior and properties of aqueous Ca(II) on the SiO2/CPAM composites were also investigated. The effect of the pH value, the initial Ca(II) concentration, adsorption time, and temperature on adsorption properties were examined. The results showed that the SiO2/CPAM composites displayed a high adsorption performance for aqueous Ca(II). The maximum adsorption capacity of the SiO2/CPAM composites for Ca(II) was 123.4 mg•g-1 at room temperature and pH 9. The adsorption behavior was in agreement with the Langmuir isotherm model. The adsorption was an endothermic and spontaneous process. Adsorption kinetics fitted well with the pseudo-second-order model. The adsorption of Ca(II) on the SiO2/CPAM composites was mainly attributed to chemical interaction, and chelation was more significant than electrostatic interaction.

  • Researchpp 3571-3584Yi, B., Yuan, Q., Cao, H., Wang, M., Niu, W., and Yan, S. (2018). "Combustion characteristics of densified cattle manure briquette in an isothermal condition," BioRes. 13(2), 3571-3584.AbstractArticlePDF
    The densification process of cattle manure (CM) and its combustion characteristics in air were studied under isothermal conditions. To be better aligned with practical applications, cotton stalk (CS) and corn cob (CC) were chosen in this paper as the controls. The stability of densified biomass briquettes under compressive force of 20 kN, 30 kN, 40 kN, and 50 kN were studied. Factors affecting the densification of biomass, including moisture concentration, densification pressure, and briquette size were studied, in addition to combustion conditions including heating rate and O2 concentration. The moisture concentration contained in the densified biomass briquettes were set at 5%, 10%, 15%, and 20%. The results showed a good stability of briquettes of CM (CM-B) under various densification pressures. The effects of moisture concentration on the combustion characteristics were small for CM-B. The influence of the densification pressure and O2 concentration on the combustion characteristics was a monotonic change. In summary, considering the stability and economy, 30 kN and 30% O2 concentration were judged to be favorable. The combustion characteristics of the CM-B did not monotonically increase with the size. The study’s results showed that the CM-B could be used as a fuel under certain conditions.
  • Researchpp 3585-3602Li, Y., Wang, B., Ma, M., and Wang, B. (2018). "The influence of pre-treatment time and sulfuric acid on cellulose nanocrystals," BioRes. 13(2), 3585-3602.AbstractArticlePDF

    Cellulose nanocrystals (CNCs) were produced with different pre-mixing times between the cotton fiber and the sulfuric acid at room temperature, prior to the reaction at 45 °C. The CNC0 and CNC60 films were prepared using vacuum filtration methods. Based on transmission electron microscopy observations, the dimension and yield of CNCs gradually decreased with increasing pre-mixing time. Considering the balance of yield and quality of CNCs, CNC0 was chosen as the optimal product. The synthetic process played an important role in the production of CNCs. Various CNCs had similar crystallinity index values with the increased pre-mixing time. The decreased contact angle was the result of decreased dimensions of CNCs or the additional sulfate group at the surface of the CNCs. Both thermogravimetric and contact angle analysis are sensitive for the constituents of CNCs.

  • Researchpp 3603-3614Hernández, J., Romero, V., Escalante, A., Toriz, G., Rojas, O., and Sulbarán, B. (2018). "Agave tequilana bagasse as source of cellulose nanocrystals via organosolv treatment," BioRes. 13(2), 3603-3614.AbstractArticlePDF

    Cellulose nanocrystals (CNCs) were isolated from Agave tequilana residues derived from ethanol production. Hemicelluloses and lignin extraction from agave bagasse was carried out via organosolv (ethanol/acetic) digestion followed by conventional sulfuric acid hydrolysis. The ethanol/acetic acid treatment resulted in cellulose yields of approximately 67% after lignin and ash removal. Compared to soda and sodium chlorite treatments with organosolv, the time and chemical load needed for delignification were remarkably reduced. The morphology of the cellulose fiber obtained in the three treatments was between 0.55 and 0.62 mm, with which CNC was obtained in the order of 83 to 195 nm in length. It is noteworthy that the longest cellulose fibers and nanocrystals were obtained from organosolv cellulose. The organosolv treatment led to a high purity cellulose, derived CNCs with a minimum energy consumption and mild chemical usage, and also considered the use of material streams associated with distillation processes. Thus, a viable alternative is suggested for the production of high quality CNC from widely available residual biomass that otherwise poses environmental and health-related risks.

  • Researchpp 3615-3626Paluš, H., Parobek, J., Dzian, M., and Šupín, M. (2018). "Determinants of sawnwood consumption in Slovakia," BioRes. 13(2), 3615-3626.AbstractArticlePDF

    This paper aimed to determine coniferous and non-coniferous sawnwood demand drivers and used historical data on their development as independent variables in the sawnwood demand models. The study presented a general form of ad hoc model that explained sawnwood consumption per capita as a function of a range of socio-economic factors. Based on the theory of demand, the most important factors were identified to enter the regression model including significant price and income variables. In the case of the non-coniferous sawnwood model, time lag variables were applied. The results of the estimated econometric models confirmed the presence of different explanatory variables for both types of sawnwood. While consumption per capita of both coniferous and non-coniferous sawnwood was determined by the activities of the construction sector, and demand appeared to be very elastic in relation to the number of completed dwellings, the price and substitution for other wood materials had a significant impact only on non-coniferous sawnwood.

  • Researchpp 3627-3641Lu, X., Fu, J., Langrish, T., and Lu, X. (2018). "Simultaneous catalytic conversion of C6 and C5 sugars to methyl lactate in near-critical methanol with metal chlorides," BioRes. 13(2), 3627-3641.AbstractArticlePDF

    Cellulose and hemicellulose make up roughly two-thirds of lignocellulose. Currently, research is mainly focused on converting them to different chemicals, which causes low utilization rates and high separation costs. In this work, the simultaneous conversion of C6 and C5 sugars from cellulose and hemicellulose to methyl lactate in near-critical methanol with 15 different types of metal chlorides was studied. The trends of the catalytic conversions of C6 and C5 sugars with different metal chlorides were similar. Methyl lactate yield initially increased and then decreased steadily with an increase in the pKa value of the metal ions, which suggested that medium Lewis acidity was favorable for the production of methyl lactate. A possible reaction mechanism was proposed. The results will provide direction for the preparation of heterogeneous catalysts for simultaneously converting cellulose and hemicellulose to methyl lactate.

  • Researchpp 3642-3658Huang, H., Shen, Y., Yu, J., Guo, H., Yang, F., Gu, J., and Liu, Y. (2018). "A spherical zwitterionic cellulose acetate/ graphene oxide composite adsorbent for efficient removal of Cu2+ and Cd2+ from aqueous solution," BioRes. 13(2), 3642-3658.AbstractArticlePDF

    A novel composite adsorbent was prepared by using cellulose acetate modified with zwitterion, for zwitterionic cellulose acetate (ZCA), then blended with graphene oxide (GO). The adsorbent was prepared by sol-gel method and used to remove Cu2+ and Cd2+ from aqueous solution. The morphologies, surface chemical structures, and crystallinity of the obtained adsorbents were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffractometer (XRD), respectively. N2 adsorption-desorption measurements revealed that the surface area and pore volume were 45.3 m2g-1 and 0.249 cm3g-1. For adsorption, effect of time, and pH, adsorbate concentration was investigated; different adsorption models were also evaluated. The results showed that the maximum adsorption capacity was 32.0 mg/g for Cu2+ and 27.6 mg/g for Cd2+, observed at pH 5.5 and 298 K. Simultaneously, the adsorption isotherms were well-fitted to the Langmuir model, and kinetics study showed that the adsorption process was fitted well by the pseudo-second-order model. Further regeneration experiments revealed that the adsorption of ZCA/GO was about 90% of the initial saturation adsorption capacity after repeated use 5 times, indicating that they are promising absorbents for practical application in industry.

  • Reviewpp to be addedde Assis, T., Reisinger, L. W., Pal, L., Pawlak, J., Jameel, H., and Gonzalez, R. W. (2018). "Understanding the effect of machine technology and cellulosic fibers on tissue properties – A Review," BioRes. 13(2), Page numbers to be added.AbstractArticlePDF

    Hygiene tissue paper properties are a function of fiber type, chemical additives, and machine technology. This review presents a comprehensive and systematic discussion about the effects of the type of fiber and machine technology on tissue properties. Advanced technologies, such as through-air drying, produce tissue with high bulk, softness, and absorbency. Conventional technologies, where wet pressing is used to partially dewater the paper web, produces tissue with higher density, lower absorbency, and softness. Different fiber types coming from various pulping and recycling processes are used for tissue manufacturing. Softwoods are mainly used as a source of reinforcement, while hardwoods provide softness and a velvet type surface feel. Non-wood biomass may have properties similar to hardwoods and/or softwoods, depending on the species. Mechanical pulps having stiffer fibers result in bulkier papers. Chemical pulps have flexible fibers resulting in better bonding ability and softness. Virgin fibers are more flexible and produce stronger and softer tissue. Recycled fibers are stiffer with lower bonding ability, yielding products that are weaker and less soft. Mild mechanical refining is used to improve limitations found in recycled fibers and to develop properties in virgin fibers. At the same time that refining increases strength, it also decreases bulk and water absorbency.

  • Researchpp 3659-3673Gaitán, A., and Gacitúa, W. (2018). "Morphological and mechanical characterization of electrospun polylactic acid and microcrystalline cellulose," BioRes. 13(2), 3659-3673.AbstractArticlePDF

    The goal of this work was to develop a composite material, a membrane, based on polylactic acid (PLA) reinforced with cellulose microcrystalline (MCC). Membranes based on PLA were fabricated using electrospinning. The fabrication parameters, fiber morphology, and mechanical properties were analyzed. For fabrication, 12 mL of solution (12%, weight basis, of PLA in chloroform) was used and three different injector-collector distances and three voltages were employed. The fiber morphology was observed using a scanning electron microscope (SEM). To fabricate reinforced membranes using microcrystalline cellulose (MCC), an amount of 1.0%, 3.0%, and 5.0% of MCC, based on the polymer mass, was used. The MCC distribution was observed using SEM. The membranes were tested via tensile and tearing tests according to the corresponding ASTM D882-12 (2012) and ASTM D1938-14 (2014). It was observed that plain fibers tended to form, depending on the injector-collector distances. Additionally, microfiber porosity was observed, which was attributed to the solvent evaporation. Moreover, the addition of 1% of MCC was translated into an important increase of tensile strength, which in some cases reached a 476% increase; similar effects were observed in the tear test results.

  • Researchpp 3674-3685Ge, Z., Chen, L., Luo, R., Wang, Y., and Zhou, Y. (2018). "The detection of structure in wood by X-ray CT imaging technique," BioRes. 13(2), 3674-3685.AbstractArticlePDF

    Medical computed tomography (CT) has been used in forestry science and the wood industry to explore the internal structures of trees in a non-destructive way. The wood material has great diversity in structure, density, and size. The software system for medical CT is not applicable to analyze and process sectional images of wood. In order to solve this problem, a CT imaging system, based on the principle of X-ray fan-beam scanning, was constructed for this study. The computer tomography technique was applied in the non-destructive testing of wood. Four kinds of representative specimens—laminated wood, multi knot logs, large diameter logs, and small diameter logs—were selected as scanned objects. The sinusoidal images and sectional images were reconstructed with scanning data. The results showed that the accuracy of CT images is determined by the information in the sinusoidal images, from which the shapes and locations of cracks and knots can be identified. The internal properties of wood in some tomography, such as the size, number, and location of cracks and knots, the number of tree rings, and the growth law of early wood and late wood can be visually observed. Finally, the feasibility and validity of the CT imaging system was tested as a non-destructive method for verifying the internal structures of wood.

  • Researchpp 3686-3703He, S., Luan, P., Mo, L., Xu, J., Li, J., Zhu, L., and Zeng, J. (2018). "Mineralization of recalcitrant organic pollutants in pulp and paper mill wastewaters through ozonation catalyzed by Cu-Ce supported on Al2O3," BioRes. 13(2), 3686-3703.AbstractPDF

    There has been great interest in developing cost-effective and high-performance catalysts for the ozonation treatment of biologically refractory wastewaters. This study developed a novel copper-cerium oxide supported alumina (Cu-Ce/Al2O3) catalyst for the catalytic ozonation of pulp and paper mill wastewater. The evenly distributed composite metal oxides on the surface of catalysts evidently improved the catalytic degradation efficiency. The Cu-Ce/Al2O3/O3 process increased the total organic carbon (TOC) removal by 6.5%, 9.5%, 24.5%, and 35.5%, compared with Ce/Al2O3/O3, Cu/Al2O3/O3, Al2O3/O3, and ozone alone processes, respectively. The enhanced catalytic ozonation efficiency was mainly ascribed to an increased hydroxyl radical (·OH)-mediated ozonation, both in the bulk solution and on the surface of catalysts. The surface hydroxyl groups (-OHs) of Al2O3 along with the deposited Cu-Ce oxides greatly enhanced the catalytic performance. This work illustrated potential applications of Cu-Ce/Al2O3 catalyzed ozonation for the advanced treatment of biologically recalcitrant wastewaters.

  • Researchpp 3704-3719Zou, R., Zhao, Y., Wang, Y., Duan, D., Fan, L., Dai, L., Liu, Y., and Ruan, R. (2018). "Microwave-assisted depolymerization of lignin with metal chloride in a hydrochloric acid and formic acid system," BioRes. 13(2), 3704-3719.AbstractPDF
    A microwave-assisted depolymerization method of lignin with various metal chloride catalysts (MgCl2, AlCl3, FeCl3, ZnCl2, and MnCl2) in a formic acid and hydrochloric acid system under mild conditions (160 °C for 30 min) was studied. The resulting bio-oil was identified by a gas chromatography-mass spectrometer, and the solid residue was analyzed by Fourier transform infrared spectroscopy (FT-IR). Furthermore, the molecular weight change of lignin after the reaction was measured by gel permeation chromatography. The MnCl2 catalyzed lignin to produce most aromatic monomers, including approximately 23.0% G-type, 11.9% S-type, and 14.8% H-type monomer compounds. Different metal chloride catalysts had different effects on the depolymerization of lignin, which were embodied in the type and content of the products. It was also worth noting that the catalytic effects of transition metal chlorides on lignin may have been related to each chloride’s cation radius.
  • Researchpp 3720-3739Wang, T., Rodriguez-Uribe, A., Misra, M., and Mohanty, A. (2018). "Sustainable carbonaceous biofiller from miscanthus: Size reduction, characterization, and potential bio-composites applications," BioRes. 13(2), 3720-3739.AbstractPDF

    The use of biocarbon derived from renewable resources to substitute for petroleum-based carbonaceous materials in composites and other applications often requires size reduction. Biocarbon obtained by the pyrolysis of miscanthus was subjected to ball milling from 2 to 24 h. Particle analysis was performed by combining scanning electron microscope imaging and image-based particle counting. The milled biocarbon had a highly heterogeneous shape and size distribution, making image-based analysis the most suitable method. The average particle size was reduced from above 3 µm after 2 h of milling to below 1 µm after 24 h of milling. The specific surface area doubled from 148 m²/g to approximately 300 m²/g after 2 h of milling, but it did not change with longer milling. Ball milling caused a gradual decrease of the thermal conductivity from 0.137 to 0.116 W·m-1·K-1. The ash content increased from 8 to 17% after 24 h of milling. Polypropylene composites filled with the biocarbon with and without ball milling showed lower density and comparable mechanical properties to a talc-filled composite except for lower impact strength. Using ball milled biocarbon led to a steady increase of the impact strength with longer milling time, reaching values on a par with that of the talc composite.

  • Researchpp 3740-3752Phonetip, K., Brodie, G., Ozarska, B., and Belleville, B. (2018). "Simulating solar kiln conditions using a conventional kiln," BioRes. 13(2), 3740-3752.AbstractPDF
    This study assessed the possibility of using a conventional laboratory kiln to simulate solar kiln conditions and developed a mathematical model to predict the timber quality and moisture content profile during drying. The simulated temperature in the kiln was modelled on the actual temperature of a solar kiln based on the climatic conditions of Vientiane, Laos. The modelling for moisture content profile in boards was implemented in Matlab codes, which combined fundamental equations and validated the model with measured data. Timber quality assessment was performed based on quality standard AS/NZS 4787 (2001). The simulation results were similar with the measured solar kiln temperatures to within less than 2 °C in a day. The modelling correctly described the MC profile decrease during the drying process when compared with measured data. Further work is required regarding the method of measuring the MC data and anatomical properties. Assessed against the standard, timber quality at the end of drying was all graded as Class “A”, and timber distortion was within permissible limits.
  • Researchpp 3753-3762Zhang, H., Lei, M., Zhang, W., Li, Q., Zhang, F., Li, X., and Luo, C. (2018). "Further understanding the combined bleaching process of peroxide and optical brightening agent in a spruce thermomechanical pulp," BioRes. 13(2), 3753-3762.AbstractPDF
    Optical brightening agent (OBA) has been successfully applied to a high-yield pulp (HYP) bleaching process (peroxide/OBA, or P/OBA technology) because of its effectiveness for improving the optical properties of treated pulp. In this study, P/OBA technology was optimized for the peroxide bleaching of spruce thermomechanical pulp (TMP). The results obtained were further analyzed using data processing software, and the bleaching chemical cost was estimated. The results showed that the brightness ceiling (the highest “technical brightness”) of Koyama spruce TMP from conventional peroxide bleaching was 75.5% ISO. In contrast, the brightness ceiling of the same mechanical pulp could be raised to 85.9% ISO using P/OBA technology. At a low-brightness target, OBA is not effective when added to the peroxide bleach liquor, and thus is not economical for this purpose; however, at a high-brightness target, the P/OBA technology is effective due to the remarkable brightening effect of OBA. When the brightness target was 80% ISO, an optimized economic cost of 280.2 RMB/ton can be obtained under the “relay point” conditions of 2.57% peroxide and 0.6% OBA (on o.d. pulp).
  • Researchpp 3763-3777Yao, S., Wang, C., Gao, C., Shi, L., Nie, S., and Qin, C. (2018). "Molecular simulation of reaction mechanism for hemicellulose model compound during chlorine dioxide bleaching," BioRes. 13(2), 3763-3777.AbstractPDF

    D-xylose, a hemicellulose model compound, was oxidized by chlorine dioxide under simulated bleaching conditions, and the mechanism of this reaction was investigated. The final reaction product, chloroacetic acid, was detected by gas chromatography-mass spectrometer (GC-MS). To study the generating mechanism of chloroacetic acid by D-xylose during chlorine dioxide bleaching, three reaction pathways were designed. The results showed that the biggest heat of reaction, -234.33 kJ/mol, and the minimum reaction activation energy, 44.44 kJ/mol, appeared for one of the candidate pathways (no. 2). That pathway was thermodynamically more favored. Xylitol was generated by D-xylose degradation, and then chloroacetic acid was generated by a series of oxidation, fracture, and substitution reactions on xylitol.

  • Reviewpp to be addedNelson, L., Park, S., and Hubbe, M. (2018). "Thermal depolymerization of biomass with emphasis on gasifier design and best method for catalytic hot gas conditioning," BioRes. 13(2), Page numbers to be added.AbstractPDF

    This paper reviews ways that biomass can be converted by thermal depolymerization to make synthetic gas, i.e. syngas. Biomass, being carbon neutral, is considered as a form of solar energy stored during the growing season by photosynthesis. An effective biomass is one with low moisture and ash content, high lignin content, high calorific value, and small particle size. Woody biomass with low ash content (<1%), nut shells with high lignin content (30 to 40%), and municipal solid waste with synthetic polymers are effective at creating value-added synthetic gases. An allothermal downdraft gasifier produces a low tar syngas (99.9% tar conversion) at 850 oC and provides a simple and low-cost process. Integrated gasification combined cycle (IGCC) improves thermodynamic efficiency. To avoid thermal loss, a hot gas filtration system uses trona sorption material for sulfur and halogen compounds. Secondary systems can use multiple cyclones followed by reactors employing calcined dolomite, olivine, and others for adsorption or reaction with residual sulfur, ammonia, metals, and halogens. Reforming of residual tar to syngas can take place within chambers with ceramic tubes doped with nano-nickel particles. Syngas can then be used in boilers, gas turbines for production of electricity or production of chemicals by Fischer-Tropsch conversion.

  • Researchpp 3778-3792Zhu, S., Guo, Y., Tu, D., Chen, Y., Liu, S., Li, W., and Wang, L. (2018). "Water absorption, mechanical, and crystallization properties of high-density polyethylene filled with corncob powder," BioRes. 13(2), 3778-3792.AbstractPDF
    Corncob powder filled high-density polyethylene (HDPE) composites were prepared by extrusion. The microstructure, water absorption, mechanical properties, and crystallinity of composite at different corncob powder content were investigated. Results demonstrated that when the corncob powder levels were moderate and uniformly dispersed within the HDPE matrix, the powder acted as a reinforcing agent. As the corncob content increased, the water absorption of the resulting composite gradually increased, which adversely affected the composite’s water resistance. Flexural strengths and moduli initially increased with increasing corncob powder levels, and then consequently decreased at higher powder levels; maximum values for flexural properties were achieved at 40% corncob powder content. The composite’s impact strength and toughness weakened with corncob powder addition. The X-ray diffraction and differential scanning calorimetry analyses indicated that when the corncob content increased, the peak crystallization and melting temperatures of the matrix increased and decreased, respectively. Meanwhile, the presence of the corncob restricted the movement and arrangement of the HDPE polymer chains, which affected HDPE crystal growth and causing a decrease in crystallinity.
  • Researchpp 3793-3808Li, L., Yu, J., Shen, Y., An, Y., and Wang, X. (2018). "Recovery of thermally compressed Scots pine (Pinus sylvestris L.) wood," BioRes. 13(2), 3793-3808.AbstractPDF

    Heartwood and sapwood samples of Scots pine were subjected to densification and thermal compression (180 °C to 220 °C) using a hot press, and their recovery behaviors and the involved mechanisms were investigated. Compressed wood (CW) showed poor recovery after water uptake. This deformation effectively was fixed by the subsequent high temperature treatment. To explain the phenomenon, the sorption properties of wood before and after modification by the adsorption isotherms were evaluated. The model of Hailwood and Horrobin gave the changes of the monolayer and multilayer sorption of each group samples and the relationship with wood deformation. By analyzing hygroscopic hysteresis, it was found that the removed elastic components from wood under elevated temperature had an inescapable impact on hysteresis ratio and recovery, even if it was not the only cause. In other words, the modified wood’s plasticity was responsible for its recovery.

  • Researchpp 3809-3816Munis, R. A., Camargo, D. A., De Almeida, A. C., De Araujo, V. A., Lima Junior, M. P., Morales, E. A. M., Simões, D., Biazzon, J. C., De Matos, C. A. O., and Cortez-Barbosa, J. C. (2018). "Parallel compression to grain and stiffness of cross laminated timber panels with bamboo reinforcement," BioRes. 13(2), 3809-3816.AbstractPDF
    Four cross-laminated timber (CLT) panels with and without bamboo reinforcement were prepared and evaluated. The goal was to obtain better possibilities of using this lignocellulosic panel, based on their mechanical properties. Stiffness and strength of compression parallel to grain tests were conducted to simulate the utilization of this material as freestanding walls. Panels were produced based on Pinus elliottii wood species and glued with castor oil-based polyurethane resin. Half of these structural panels were also reinforced with strips of Dendrocalamus asper bamboo species, which were added on the outer layers. There was a significant increase in the parallel compression-to-grain in the configuration of the cross-laminated timber reinforced with bamboo in the longitudinal direction, which concentrates superior resistance.
  • Researchpp 3817-3831Jiang, L., He, C., Li, X., and Fu, J. (2018). "Wear properties of wood-plastic composites pretreated with a stearic acid-palmitic acid mixture before exposure to degradative water conditions," BioRes. 13(2), 3817-3831.AbstractPDF

    Wood–plastic composites (WPCs) are experiencing rapid growth in terms of applications where they may be subject to degradation and wear. This paper investigated the effect of sorghum straw (SS) fiber, pretreated with a mixture of stearic and palmitic acids, on the wear behaviors of polyvinyl chloride (PVC) composites in alternated simulated sea water and acid rain aqueous conditions. The results showed that the water resistance of the SS/PVC composites improved noticeably after pretreatment with 0.80 wt% stearic and 0.50 wt% palmitic acid (0.8SA-0.5PA). The SS/PVC composites pretreated with 0.8SA-0.5PA exhibited high water (moisture) resistance, hardness, mechanical, thermal, and wear resistance properties. Exposure to degradative water worsened interfacial bonding, and degraded the matrix strength and heat resistance, which reduced the wear resistance of the SS/PVC composites. The wear mechanism of the SS/PVC composites after 12 d of soaking was abrasive wear.

  • Researchpp 3832-3845Abada, E. A., Masrahi, Y. S., Al-Abboud, M., Alnashiri, H. M., and El-Gayar, K. E. (2018). "Bioethanol production with cellulase enzyme from Bacillus cereus isolated from sesame seed residue from the Jazan region," BioRes. 13(2), 3832-3845.AbstractPDF

    Bio-ethanol is considered as an important renewable fuel to partly replace fossil-derived fuels. In this study, bioethanol production, which includes cellulase production, saccharification of the cellulose content of sesame seed residue, and ethanol production, was investigated. Out of the hundreds of cellulase-producing bacterial strains isolated from sesame seed residue during this study, the B isolate was found to have the highest cellulase enzyme production. This isolate was identified as Bacillus cereus by 16S rRNA sequencing. The effects of different growth parameters, including inoculum concentration, incubation time, temperature, pH, and carbon and nitrogen sources, were investigated to optimize the growth conditions of the bacterium. The maximum cellulase activity was achieved with an inoculum concentration of 3% after 48 h in a basal medium at a pH of 7 and an incubation temperature of 35 °C. The best nitrogen and carbon sources were yeast extract and sesame seed residue, respectively. The results showed the liberation of 2.3 g/L of reducing sugar by the dinitrosalicylic acid method. This total reducing sugar produced 15 g/L of ethanol after 48 h when Saccharomyces cerevisiae was used as a fermentation agent. Hence, bioethanol was successfully produced from the cellulose of sesame seed residue using the cellulase enzyme from B. cereus.

  • Researchpp 3846-3867Prasetyo, V. E., Belleville, B., and Ozarska, B. (2018). "A proposed method and its development for wood recovery assessment in the furniture manufacturing process," BioRes. 13(2), 3846-3867.AbstractPDF

    A proposed method for assessing wood recovery involves application of a machining station approach with volume and mass measurements. A medium wood furniture company located in Jepara, Indonesia was selected to develop the method. Batch measurements of the inputs and outputs for different types of indoor-furniture products at every station were collected and analysed. For the volume method, three dimensions were measured on each specimen: the length, width, and thickness. For the mass method, the specimens were weighed before and after each processing station using a balance. Based on the mass method, the average total wood recovery rate was 26.2% ± 2.3%. For individual products and per station, the significant difference in the wood recovery rate occurred only at the resawing and edging, and trimming stations. The relationship between the teak quality, product dimensions, and type of finish was significantly different, where A-quality teak, large dimensions, and polyurethane finish resulted in a higher wood recovery rate. Both methods were reliable because of insignificant differences in the wood recovery rates. However, the mass method was more efficient and practical. The proposed protocol using the mass method is a suitable and effective system because the contribution of the variance component of the method was 2.71%.

  • Researchpp 3868-3879Bardak, S. (2018). "Predicting the impacts of various factors on failure load of screw joints for particleboard using artificial neural networks," BioRes. 13(2), 3868-3879.AbstractPDF
    Innovations in the furniture industry have an important place in the global competitive environment. The use of mechanical joining techniques is rapidly increasing in the furniture industry. One of the most common mechanical joining techniques is screwing. This study investigated the impacts of screw diameter, screw length, and the distance between the screws on the failure load of screw joints in particleboard. Additionally, a model was developed on an artificial neural network model (ANN), based on experimental data, to predict the failure load of joints. The results indicated that the highest tension and compression strengths of joints were achieved when the distance is 140 mm between the screws. Joint strengths of all specimens were improved when the screw length and diameter were increased. It is necessary to estimate the effect of various factors to improve furniture joint performance. Coefficients of determination at 0.98 (tension strength test) and 0.96 (compression strength test) were predicted for the testing phase by the ANN model. All these findings established that the prediction was compatible with experimental data of tension and compression strengths. The results of the analysis showed that the neural network approach was effective in predicting the failure load of screw joints and showed that the ANN model has great potential in the design optimization of furniture assemblies.
  • Researchpp 3880-3891Ouyang, T., Wang, L., Cheng, F., Hu, Y., and Zhao, X. (2018). "Lignocellulose fractionation and lignin depolymerization using glycerol and acidic ionic liquids: Identification of the main products by GC-MS," BioRes. 13(2), 3880-3891.AbstractPDF

    Difficulties in fractionation and subsequent conversion of lignocellulosic biomass have restricted the development of sustainable biorefineries of lignocellulosic materials. Herein, an aqueous glycerol/acidic ionic liquid (AGAIL) process of coir was carried out under atmospheric and autogenerated pressure to investigate the lignocellulose fractionation and understand the main conversion products generated during the process. Additionally, the depolymerization capacity of the AGAIL system on lignin was also estimated by analyzing the main degradation products. The results indicated that the process under autogenerated pressure presented much higher delignification efficiency and more effective lignocellulose conversion capability than those under atmospheric pressure. Ribitol and monomeric aromatic compounds were identified by gas chromatography-mass spectrometry (GC-MS) as the main conversion products of carbohydrates and lignin, respectively. The glycerol/AIL system was shown to be able to depolymerize coir lignin with a resulting lignin depolymerization extent of 28.1%. The main lignin depolymerization products were monomeric aromatic compounds.

  • Researchpp 3892-3904Porakiewicz, B., Wieczorek, D., Bocho-Janiszewska, A., Klimaszewska, E., Tanaka, C., & Darmawan, W. (2018). "A theoretical model for the increases in cutting edge recessions during milling of nine species of wood," BioRes. 13(2), 3892-3904.AbstractPDF

    The high-speed steel (HSS) cutting tool edge recession increase (VB) from milling wood of nine wood species with very different properties were analyzed. Theoretical simulations showed that the synergistic effect of the wood density (D), hard mineral contamination (HMC), and high temperature tribochemical reactions (HTTR), as well as initial edge recessions were important factors that accelerated wearing on the examined cutting edges.

  • Researchpp 3905-3921Zhou, A., Huang, Z., Shen, Y., Huang, D., and Xu, J. (2018). "Experimental investigation of mode-I fracture properties of parallel strand bamboo composite," BioRes. 13(2), 3905-3921.AbstractPDF
    Parallel stand bamboo (PSB) is a high-quality wood-like bamboo composite. Failure due to cracking is a major concern in the design of PSB components for building structures. The mode-I fracture properties of PSB composite were studied. The wedge splitting method was employed as the test approach. Numerical analyses were conducted to determine the appropriate test specimen dimensions so that valid fracture toughness could be obtained. An R-curve was evaluated in accordance with the equivalent linear elastic fracture mechanics (LEFM) theory. It was found that the initial crack depth ratio should be less than 0.4 for the fracture toughness test. The fracture toughness of PSB is higher than that of commonly used woods, and their fracture behavior is similar, exhibiting quasi-brittle behavior. The R-curve of the PSB exhibits rising behavior until the critical crack length is reached. However, the post-peak R-curve exhibits a descending behavior, contrary to that of quasi-brittle materials, which present a plateau in post-peak crack extension.
  • Researchpp 3922-3931Zhao, H., Wu, H., Hu, H., Li, Y., Li, J., and Zhang, X. (2018). "Cooperative decomposition of hydrogen peroxide by lignin-combined transition metals in pulp bleaching," BioRes. 13(2), 3922-3931.AbstractPDF

    The effects of lignin-combined manganese ion, iron ion, and lignin-combined iron and manganese on the decomposition of hydrogen peroxide were investigated. Elemental analysis and inductively coupled plasma-atomic emission spectrometry were used to analyze the chemical features of the lignin composites and the amount of metal ions present in the solution or adsorbed on lignin, respectively. The results showed that the main transition metal elements remaining in the precipitated lignin were Fe, Mn, and Cu. The hydrogen peroxide decomposition in the presence of lignin-combined transition metal was represented by pseudo-first-order kinetics, and the pseudo-first-order rate constant (kobs) of peroxide decomposition with lignin-combined iron was 0.0068 min-1, while it was 0.0063 min-1 in the presence of lignin-combined manganese. A synergistic effect of manganese and iron combined with lignin on peroxide decomposition was demonstrated, and a kobs value of 0.0053 min-1 was obtained. The mixed addition of magnesium sulfate (MgSO4), sodium silicate (Na2SiO3), and ethylene diamine tetraacetic acid disodium salt (Na2EDTA) resulted in an optimal reduction in peroxide decomposition when single lignin-combined metal ion existed. However, adding Na2EDTA alone had an optimal effect on the reduction of peroxide decomposition in the presence of lignin-combined iron and manganese, with a kobs value of 0.0004 min-1.

  • Researchpp 3932-3948Chen, T., Luo, L., Li, Z., Zhang, Z., Zheng, S., Zhu, Z., He, J., & Zhao, W. (2018). "Preparation and characterization of nitrogen and oxygen heteroatom codoped activated biocarbons from edamame shell," BioRes. 13(2), 3932-3948.AbstractPDF

    A simple procedure was evaluated to prepare cost-effective heteroatom self-doped porous carbons from edamame shell using a two-step carbonization and activation process. The morphological, structural, textural properties and N2/CO2 adsorption–desorption were investigated. The results showed that edamame shell, which is abundant in nitrogen and oxygen, is an ideal precursor for preparing heteroatom self-doped porous carbons. The N and O contents of the prepared activated carbons (ACs) ranged from 1.20 wt% to 1.81 wt% and 5.13 wt% to 9.98 wt%, respectively. Furthermore, the specific surface area of 1835 m2/g of the N and O doped ACs resulted in mainly microporosity, which suggested that it has promising potential for wide applications in the fields of catalysis, energy conversion, energy storage devices, and adsorption.

  • Researchpp 3949-3957Peşman, E., and Laloğlu, S. (2018). "Recycling of colored office paper. Part I: Pre-bleaching with formamidine sulfinic acid at pulper," BioRes. 13(2), 3949-3957.AbstractPDF

    The possible use of formamidine sulfinic acid (FAS) for pre-bleaching of colored office paper in the stage of pulping was investigated. In addition, the effects of FAS pre-bleaching on different colors were examined. Colored office papers were mixed with white office paper at a 1:4 ratio. FAS was added as 0.25%, 0.50%, 0.75%, 1.00%, and 2.00% into the pulper. Reduction ability of colors with FAS were determined as yellow, red, green, and blue according to L*, a*, b*, ΔE, and reflectance spectrum at 220 nm to 900 nm wavelength. In other words, it was determined that FAS succeeded on the yellow, red, and green colored waste paper, but it failed on the blue colored waste paper at 10 minute pre-bleaching conditions. On the other hand, in mixed colored waste paper, which can better represent industrial applications, the color difference (ΔE) were calculated as 32.0 with 1% FAS pre-bleaching. This result is successful for pre-bleaching, which is an auxiliary process during re-pulping of waste paper.

  • Researchpp 3958-3970Karaduman, Y. (2018). "Experimental investigation on the flexural and dynamic mechanical properties of jute fiber/cork-reinforced polyester sandwich composites," BioRes. 13(2), 3958-3970.AbstractPDF
    The flexural and dynamic mechanical behavior were evaluated for a new jute woven fabric/cork-reinforced polyester sandwich composite. To improve the fiber/matrix adhesion, jute fibers were treated with sodium hydroxide (NaOH) and silane prior to composite preparation. The results indicated that the flexural strength and modulus of the composites increased after the alkali and alkali + silane treatments. Similarly, dynamic mechanical parameters, such as storage and loss modulus of the sandwiches, were enhanced as a result of alkali and silane treatments due to a better fiber/matrix adhesion compared with the untreated composites. It was also shown that the damping parameter decreased after the interfacial treatments, which indicated that the energy damping efficiency decreased as the interface quality was improved.
  • Researchpp 3971-3985de la Cruz-Quiroz, R., Carrillo-Nieves, D., Aguilar-Zárate, P., Carrillo-Inungaray, M. L., Parra-Saldívar, R., and Iqbal, H. M. N. (2018). "Utilization of lignocellulose-based orange peel waste for induced sporulation of Trichoderma asperellum via Box-Behnken matrix design," BioRes. 13(2), 3971-3985.AbstractPDF

    The feasibility of using orange peel residues as a substrate for induced sporulation of Trichoderma asperellum was evaluated. The Box-Behnken matrix (BBM) design was used to screen the effects of several parameters, including the effect of pH, inoculum, and moisture under solid-state fermentation culture conditions. The study was performed in two experimental steps (screening and optimization). Moisture content and pH were determined to be the most influential parameters on spore production during the screening stage. A Box-Behnken design was used to optimize and to define the interaction of the selected parameters. The moisture content was determined as the most significant parameter affecting spore production. An inoculum of 1 × 106 spores g-1, pH 6.07, and moisture content of 69.0% was the combination of conditions observed to achieve the maximum production of 2.04 × 109 spores g-1. The experimental value of 2.16 × 109 spores g-1 (from the experimental model) showed a good fit to the regressed model, with a standard error of 5%. Based on this work, a high yield of spores was obtained at 144 h of cultivation time, indicating that it is a feasible approach to use orange peel as a substrate for biomass and spore production.

  • Researchpp 3986-3993Kong, H., Chen, S., He, W., Chen, C., Wu, J., Ma, H., and Yang, F. (2018). "Preparation and properties of thermally conductive copper paper," BioRes. 13(2), 3986-3993.AbstractPDF

    A new thermally conductive copper paper was prepared with cellulose pulp and ultrafine copper powder in a traditional paper making process. The thermal conductivity of the copper paper was studied in different weight ratios, and the surface morphology was observed by scanning electron microscopy (SEM). The results showed that the addition of copper powder enhanced the thermal conductivity of copper paper distinctly, with a maximum of up to 0.560 w•m-1•K-1 in the weight ratio of pulp/copper of 1:12, which was an increase of 143% compared with the paper without copper. Scanning electron microscopy images showed that copper papers consisted of copper powder particles distributing compactly on the fiber surface. The tensile index of copper paper decreased compared with the paper without filler. A calendaring process was used to improve the combination between copper particles and fibers and to enhance the thermal conductivity of copper paper.

  • Researchpp 3994-4007Tanase, C., Talmaciu, A. I., Bâra, I. C., Boz, I., Volf, I., Oroian, S., and Popa, V. I. (2018). "New aspects of biomass waste valorization: Spruce bark crude extracts as plant growth regulators," BioRes. 13(2), 3994-4007.AbstractPDF

    The effects of spruce bark crude extracts were evaluated relative to basil (Ocimum basilicum L.) plantlet development and metabolic processes (cellular division and histo-anatomical modification) involved in breeding. Natural phenolic compounds were separated as crude extracts by conventional and green extraction techniques, in a primary biorefining process, from Picea abies L. waste bark. First, the influence of phenolic compounds, in different concentrations, on the basil plants’ main biosynthetic processes was analyzed. The mitotic indices and chromosomal aberrations of the plantlets were monitored. There was a significantly positive action of the studied bioproducts on basil root and stem growth, biomass accumulation, and photo-assimilating pigment synthesis. The natural polyphenols triggered an intensification of metabolic processes and cell division, yielding a high mitotic index and good development of vascular bundles. The results supported the possibility of exploiting spruce bark wastes by conversion into valuable bio-compounds, with uses as innovative products in green biotechnology, as simple growth bioregulators, for example, or for biotech crops.

  • Researchpp 4008-4017Saavedra-Molina, J. L., Méndez-Iturbide, D., Gomez-Camarillo, M. A., and Sanchez, C. (2018). "Mycelial growth and fruit body nutritional composition of Pleurotus species grown on different lignocellulosic waste-based media," BioRes. 13(2), 4008-4017.AbstractPDF

    Pleurotus species are edible mushrooms that possess the ability to degrade lignocellulose and are cultivated on lignocellulosic substrates to produce fruiting bodies that are appreciated for their nutritional and culinary values. Radial growth rate (ur), mycelial biomass, and intracellular glycogen and protein contents were evaluated in the colonies of two strains of P. ostreatus (strains 26 and 50) and one strain of P. pulmonarius (strain 35) grown on barley straw extract agar, corn stover extract agar (CSEA), wheat straw extract agar, and glucose-yeast extract agar (GYEA). The nutritional composition of the Pleurotus fruit bodies cultivated on barley straw, corn stover, and wheat straw were also determined. Of all of the strains, P. ostreatus 50 showed the highest ur on the CSEA and GYEA, and P. ostreatus 26 showed the greatest mycelial biomass production on the lignocellulosic waste-based agar media (LWAM). All of the Pleurotus strains showed the greatest and lowest glycogen contents on the CSEA and GYEA, respectively. These results showed that the LWAM are more suitable for mycelial growth than a glucose-based agar medium, and that Pleurotus fruit bodies cultivated on corn stover had the highest nutritional value compared with fruit bodies grown on the wheat and barley substrates.

  • Researchpp 4018-4028Chen, Z., He, Z., Zhang, L., and Ni, Y. (2018). "In situ grafting of chitosan onto cellulosic fibers using maleic anhydride for paper wet strength improvement," BioRes. 13(2), 4018-4028.AbstractPDF

    The wet strength of paper is an important property in its various applications. In this paper, chitosan was employed as an additive to improve the wet strength of paper using a dipping process, and maleic anhydride (MA) was used to improve the retention of chitosan. The underlying mechanism was the bridging effect of MA, via the formation of esters between MA and cellulose and amides between MA and chitosan, both of which were supported by the FT-IR results. The temporary and permanent wet strengths of the paper increased significantly, and the key parameters were 1) the concentration of MA and chitosan, 2) dipping duration, and 3) curing temperature. The temporary and permanent wet strengths reached 31.6% and 29.7%, respectively, at a concentration of treating solution of 1%, dipping time of 12 h, and curing temperature of 90 °C. At a curing temperature of 170 °C under otherwise the same conditions, both the temporary and permanent wet strengths were higher than 50%.

  • Researchpp 4029-4045Buck, D., and Hagman, O. (2018). "Production and in-plane compression mechanics of alternatively angled layered cross-laminated timber," BioRes. 13(2), 4029-4045.AbstractPDF
    Increasing awareness of sustainable building materials has led to interest in enhancing the structural performance of engineered wood products. This paper reports mechanical properties of cross-laminated timber (CLT) panels constructed with layers angled in an alternative configuration on a modified industrial CLT production line. Timber lamellae were adhesively bonded together in a single-step press procedure to form CLT panels. Transverse layers were laid at an angle of 45°, instead of the conventional 90° angle with respect to the longitudinal layers’ 0° angle. Tests were carried out on 20 five-layered CLT panels divided into two matched groups with either a 45° or a 90° configuration; an in-plane uniaxial compressive loading was applied in the principal orientation of the panels. These tests showed that the 45°-configured panels had a 30% higher compression stiffness and a 15% higher compression strength than the 90° configuration. The results also revealed that the 45°-configured CLT can be industrially produced without using more material than is required for conventional CLT 90° panels. In addition, the design possibility that the 45°-configured CLT can carry a given load while using less material also suggests that it is possible to use CLT in a wider range of structural applications.
  • Researchpp 4046-4057Huang, L., Chen, C., Gao, S., Cui, L., Wang, S., Song, X., Chen, F., Liu, J., & Yu, S. (2018). "Preparation and characterization of a high performance emulsion using a polymeric emulsifier and AKD," BioRes. 13(2), 4046-4057.AbstractPDF

    An alkylketene dimer (AKD) emulsion was prepared using a neotype polymeric emulsifier. The water resistance, surface tension, stability, grain diameter, and contact angle of the obtained AKD emulsion were investigated under different conditions, such as emulsification temperature, emulsification time, solids content, and amount of emulsifier. The experimental results demonstrated that the sizing effect of the AKD emulsion was fairly good under the following conditions: emulsification temperature, 75°C; emulsification time, 9 min; solids content, 10%; and the amount of emulsifier, 3%.

  • Researchpp 4058-4074Paunonen, S., Timofeev, O., Torvinen, K., Turpeinen, T., and Ketoja, J. A. (2018). "Improving compression recovery of foam-formed fiber materials," BioRes. 13(2), 4058-4074.AbstractPDF

    Foam technology enables the preparation of new fiber-based materials with reduced density and improved mechanical performances. By utilizing multi-scale structural features of the formed fiber network, it is possible to enhance the elasticity of lightweight cellulose materials under compressive loads. Sufficient strength is achieved by optimally combining fibers and fines of different length-scales. Elasticity is improved by adding polymers that accumulate at fiber joints, which help the network structure to recover after compression. This concept was demonstrated using natural rubber as the polymer additive. For a model network of viscose fibers and wood fines, the immediate elastic recovery after 70% compression varied from 60% to 80% from the initial thickness. This was followed by creep recovery, which reached 86% to 88% recovery within a few seconds in cross-linked samples. After 18 h, the creep recovery in those samples was almost complete at up to 97%. A similar improvement was seen for low-density materials formed with chemi-thermomechanical fibers. The formed structure and elastic properties were sensitive not only to the raw materials, but also to the elastomer stiffness and foam properties. The improved strain recovery makes the developed cellulose materials suitable for various applications, such as padding for furniture, panels, mattresses, and insulation materials.

  • Researchpp 4075-4092Myja, D., Loranger, É., and Lanouette, R. (2018). "TEMPO mediated oxidation optimization on thermomechanical pulp for paper reinforcement and nanomaterial film production," BioRes. 13(2), 4075-4092.AbstractPDF
    The 4-acetamido-TEMPO mediated oxidation system is well known on pure cellulose, but further investigation on more complex cellulose sources, such as thermomechanical pulp that is also composed of hemicelluloses and lignin, is needed. The reaction on wood pulp allows improvement in paper strength and nanofibril material production. However, the effects of the reaction parameters are not known enough to scale up the oxidation. With the help of two experimental designs, the chemical amounts, reaction temperature and time, sodium hypochlorite injection time, and nanofibril dispersion time were all studied. During the experiments, it was possible to observe pulp bleaching or delignification. Increasing the 4-acetamido-TEMPO amount promoted the pulp oxidation. In contrast, a large excess of sodium bromide and sodium hypochlorite was advantageous for pulp bleaching and delignification. High temperature favored the oxidation but delignification was induced by the oxidation. For the paper reinforcement, chemical amounts were optimized according to the end user needs. For nanomaterial production, both oxidation and delignification were needed. The reaction had to generate a significant delignification and increase pulp carboxyl content higher than 1600 mmol/kg to be able to produce nanofibril material. The results showed new leads on the various times required for future industrial implementation.
  • Researchpp 4093-4101Yue, X., Du, X., and Xu, Y. (2018). "Dynamic viscoelasticity of kraft black liquor at a high dry solid content with the addition of sodium aluminate," BioRes. 13(2), 4093-4101.AbstractPDF
    Black liquor is not only a by-product of the papermaking industry but also an energy source that is often burned at a high solids content in a recovery furnace because of its high combustion efficiency and stability. However, the silicon content of bamboo kraft black liquor (BKBL) is much higher than that of softwood kraft black liquor, and the presence of silicon causes serious problems in the recovery cycle. Sodium aluminate, when used as a desilicating agent during combustion, has an excellent effect on the removal of silicon from BKBL. In this work, the dynamic viscoelasticity of BKBL with the addition of sodium aluminate was studied using a rotational rheometer. The results indicated that the BKBL was a pseudo-plastic fluid. A power-law model and the Cross model accurately described the relationship between the dynamic viscosity and angular frequency. The zero shear rate viscosity of BKBL was relatively high, even at a high temperature. The addition of sodium aluminate increased the viscosity of BKBL when the loading was 1.5 wt.%, but it had the opposite effect when its loading was 0.5 wt.%. With an increase in the angular frequency, the effect of sodium aluminate on the viscosity became less apparent.
  • Researchpp 4102-4117Wang, S., Lin, X., Li, Z., Yi, W., and Bai, X. (2018). "Thermal and kinetic behaviors of corn stover and polyethylene in catalytic co-pyrolysis," BioRes. 13(2), 4102-4117.AbstractPDF

    Thermal decomposition characteristics and kinetics of high-density polyethylene (HDPE), corn stover (CS), and their blended mixture (1:1 w/w ratio) during non-catalytic and catalytic co-pyrolysis were studied via thermogravimetric analysis (TGA). The results indicated synergetic interactions between the biomass and the plastics during co-pyrolysis as measured by weight loss (ΔW); this effect was attributed to radical interactions during co-pyrolysis. The pyrolysis catalysts with higher nickel loadings (5%, 10%, and 15%) appreciably diminished the solid residue. Kinetic studies indicated that the pyrolysis was a first-order reaction based on the fitted thermogravimetric data. The activation energy (E) and pre-exponential factor (A) ranged between 26.13 kJ/mol to 392.67 kJ/mol and between 156.24 min-1 to 9.19 x 1023 min-1, respectively. There was a kinetic compensation effect (KCE) observed among the two kinetic parameters. The activation energy (E) decreased for each pyrolysis stage with the presence of a catalyst. The results indicated that catalytic co-pyrolysis could provide great potential for reducing the pyrolysis energy input.

  • Researchpp 4118-4131Gomes da Silva, C. E., de Almeida, D. H., de Almeida, T. H., Chahud, E., Melgaço Nunes Branco, L. A., Campos, C. I., Rocco Lahr, F. A., and Christoforo, A. L. (2018). "Influence of the procurement site on physical and mechanical properties of Cupiúba wood species," BioRes. 13(2), 4118-4131.AbstractPDF
    Studies that estimate technological properties of tropical wood species (especially those from the Amazon Rainforest) for their use in building construction, mainly structures, are very desirable. This paper aimed to investigate, aided by ABNT NBR 7190 (1997) recommendations, by Kruskal-Wallis analysis of variance (ANOVA), and regrouping bootstrap simulation technique, the influence of procurement sites (Caracaraí and Bonfim do Sul, State of Roraima, Brazil) and Cláudia (State of Mato Grosso, Brazil) on physical and mechanical properties of a Cupiúba wood species (Goupia glabra Aubl.). It was intended to assess the possibility of estimating (by linear, exponential, geometric, and logarithmic mathematical models) the physical and mechanical properties investigated as a function of density at 12% of moisture content. The results of ANOVA indicated equivalence in 94% of the properties of the Caracaraí and Claudia sites, and no equivalence in 50% of the properties in the Bonfim site; even after extrapolation by the bootstrap simulation technique, the non-equivalence was still 44%. Results obtained from the regression models implied a possibility of an estimate of the physical and mechanical properties of Cupiúba wood species using density as the estimator.
  • Researchpp 4132-4144Zhang, H., Gao, H., Wang, Z., and Zhu, X. (2018). "Polymerization processes of emulsifier-free pickering emulsion stabilized by nanocrystalline cellulose," BioRes. 13(2), 4132-4144.AbstractPDF
    Styrene was used as the monomer, ammonium persulfate as the initiator, and the nano-cellulose (NCC) obtained by hydrolyzing microcrystalline cellulose with sulfuric acid was used as the stabilizer for solid particles. Then the Pickering emulsion, which can be stable for a certain time, was prepared by emulsifier-free emulsion polymerization by ultrasonic homogenization. The solid content and conversion and emulsion rates were calculated. The material was examined by infrared spectroscopy and scanning electron microscopy. Its stability and other characteristics were described. The average NCC particle size was 187.2 nm, and the particle size distribution coefficient of PDI was 0.394. The styrene Pickering emulsion was stable for 20 d, and the emulsion rate was stable at approximately 0.7. The conversion rate of the polymerization emulsion was approximately 80%. When the content of NCC was approximately 3% to 4%, the maximum degree of sizing was approximately 42 s, and the water resistance was better than Pickering emulsion with other NCC additions.
  • Researchpp 4145-4158Lee, H., Chang, S. J., Kang, Y., Lee, D. R., and Kim, S. (2018). "Analysis of heating energy reduction of wooden-based Korean Hanok using passive houses planning package (PHPP)," BioRes. 13(2), 4145-4158.AbstractPDF
    This study sought to design a low-energy Hanok house through the PHPP energy simulation program. The goal is to retain the spirit of Hanok, a traditional Korean house style, and spread the adoption of the Hanok style. Using the standard drawings of the wood-frame house and the Hanok, the analysis of the heat loss of each element and the annual heat demand showed that the Hanok had about six times higher energy demand, and the heat loss was mostly associated with the envelope. As a result of applying to the Hanok principles in the same way as the insulation condition of a modern wood-frame house, the analysis showed an opportunity for about an 80% energy reduction. The need for design standards for the development of low-energy Hanok was confirmed.
  • Researchpp 4159-4174Xu, J., He, S., Li, J., Yu, H., Zhao, S., Chen, Y., and Ma, L. (2018). "Effect of vacuum freeze-drying on enhancing liquid permeability of Moso bamboo," BioRes. 13(2), 4159-4174.AbstractPDF
    Permeability has been proven useful and important in the application and basic research of biomaterials, such as anti-mildew, dyeing, or other impregnated modification, especially in the study of bamboo. However, the traditional methods of improving bamboo’s permeability are chemical treatments and destructive physical treatments. This study proposed an innovative way to produce more porous bamboo with effective penetration via the vacuum freeze-dried method. The greatest advantage of this method is that the original form of bamboo was preserved according to the three-phase principle of water. From scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), the pore characteristics and microstructure of moso bamboo were characterized, the porosity of bamboo increased to 73%, a microporous bamboo was formed, and the liquid penetration of bamboo improved noticeably. Meanwhile, the vacuum freeze-dried method turned bamboo into a mould-preservation biomaterial that effectively removed starch grains. Moreover, testing the mechanical properties showed that the vacuum freeze-dried method did not have a noticeable impact on bamboo’s mechanical properties, although it had a remarkable impact during later-stage processing and utilization. More importantly, this work provided a good example with which to expand high-value applications of bamboo resources.
  • Researchpp 4175-4186Zhuang, H., Shan, S., Fang, C., Song, Y., and Xue, X. (2018). "Advanced treatment of paper mill wastewater using electro-Fenton process with novel catalytic particle electrodes," BioRes. 13(2), 4175-4186.AbstractPDF

    Waste rice straw and iron-containing sludge were converted into catalytic particle electrodes (CPEs). The CPEs were tested for their ability to strengthen electro-Fenton (EF) oxidation of real paper mill wastewater. The prepared CPEs were characterized by different techniques including scanning electron microscopy, X-ray diffraction, BET surface area, and X-ray fluorescence. The CPEs exhibited excellent electro-catalytic activity and appreciably reduced the levels of pollutant parameters during EF process at near neutral pH conditions. Additionally, the treated wastewater was more biodegradable and had lower toxicity, which met Chinese effluent discharge criteria. Optimized treatment conditions used were a current density of 10 mA/cm2, a CPEs dosage of 1.0 g/L, and an aeration rate of 5 L/min. Based on the measurements of H2O2 and hydroxyl radicals (•OH), the enhancement of catalytic activity was attributed to more in situ •OH being produced from the H2O2 which was generated from dissolved oxygen (DO). Moreover, the CPEs showed superior stability, and successive recycle runs were completed with efficient and economical application advantages.

  • Researchpp 4187-4201Zhang, X., Zhao, Y., Chen, Z., Jing, S., Zhuo, H., Hu, Y., Zhong, L., Peng, X., and Sun, R. (2018). "Effect of cationic hemicellulosic fractions from corncob obtained by graded ethanol precipitation on recycled paper strength," BioRes. 13(2), 4187-4201.AbstractPDF

    This study investigated how various hemicellulosic fractions extracted from corncob, which have different chemical structures, affect paper strength properties when derivatized and used as paper strengthening agents. Four hemicellulosic fractions with different molecular weights and heteropolymer branching were extracted from corncob via a selective precipitation process; afterwards, the fractions were then chemically modified to obtain cationic hemicelluloses, which were used as strengthening agents for recycled pulp papermaking. These cationic hemicellulosic fractions improved the mechanical strengths of handsheets composed of recycled fibers and paper machine white water fines; however, the level of improvement was different among the fractions. Cationic hemicellulosic fractions showed a better improvement on the strength of handsheets without fines than that of the handsheets with fines. Especially, cationic hemicellulosic fraction obtained from 30% ethanol aqueous medium had the highest molecular weight and the highest substitution degree and thus showed the best enhancement in the mechanical strength of handsheets. Hence, this work demonstrates how to utilize hemicelluloses efficiently as strength agents for recycled pulp papermaking.

  • Reviewpp to be addedTeaca, C., Tanasa, F., and Zanoaga, M. (2018). "Multi-component polymer systems comprising wood as bio-based component and thermoplastic polymer matrices – An overview," BioRes. 13(2). Page numbers to be added.AbstractPDF

    The production of wood-based polymer composites has gained increasing interest in recent years, especially regarding sustainability issues, aiming at the recovery, reuse, and up-cycling of by-products from natural resources exploitation, as well as plastics. Due to their reduced cost, low density, and availability, wood components (fibers, flour) are attractive fillers for thermoplastic polymer matrices used in multi-component systems. Performance of wood-based thermoplastic materials mainly depends on the type and strength of interactions at the polymer-wood interface. Different low polarity polymers (high/low density polyethylene, polypropylene, polyvinylchloride) can be successfully used as matrices in such formulations. Various methods may be applied in order to obtain specified performance attributes of wood-based composites. Addition of appropriate compatibilizing agents, chemical and/or physical modification of the filler in order to improve its compatibility towards the matrix, or a judicious combination of these approaches may be employed. This paper briefly reviews some recent literature data, as well as research results by the authors, aiming at a comparative assessment of the materials properties (structure, thermal, mechanical and water sorption behavior) in correlation with the nature and type of components, processing, recycling options, and environmental impact.

  • Researchpp 4202-4223Song, W., Zhu, M., Lin, W., and Zhang, S. (2018). "Determining optimum material mixture ratio and hot-pressing parameters for new hybrid fiber-reinforced composites: Modeling and optimization by response surface methodology," BioRes. 13(2), 4202-4223.AbstractPDF

    As a bamboo processing residue, bamboo green (B) was evaluated as an additive to wood fiber (W) for developing composite panels. According to a Box-Behnken design, urea-formaldehyde resin-glued panels were fabricated from blends of B and W, with three preparation variables: B weight percentage in fibrous material (20%, 40%, and 60%), hot-pressing temperature (160 °C, 180 °C, and 200 °C), and hot-pressing duration (60, 120, and 180 s). The panels were tested for water uptake, thickness expansion, bending strength, and bending modulus. The results showed that the physical-mechanical properties of panels satisfied the strictest requirements of GB/T 11718 (2009). Four quadratic models were established to predict the four properties using the three variables. All models were statistically significant, with coefficients of variation below 5% and coefficients of determination beyond 0.96. An analysis of variance revealed that all variables significantly influenced panel properties. Their effect mechanisms were discussed. A response surface analysis demonstrated that, for different properties, the optimum B percentage, hot-pressing temperature, and hot-pressing duration ranged from 35% to 49%, 173 °C to 198 °C, and 111 s to 134 s, respectively. When all four properties were simultaneously optimized, the optimum preparation conditions were 42%, 179 °C, and 119 s, respectively.

  • Researchpp 4224-4238Sablik, P., Giagli, K., Paschová, Z., Oravec, M., Gryc, V., and Rademacher, P. (2018). "FexIKA method parameters affecting black locust heartwood extraction yield," BioRes. 13(2), 4224-4238.AbstractPDF

    The influence of certain adjustable parameters (sample property, temperature, and solvent type) on the advanced fexIKA extraction outputs was determined. Extracts were obtained from black locust (Robinia pseudoacacia L.) heartwood and analysed by high-performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS). The amount of extract yield remained similar, regardless of the wood particle size, whereas the total amount of phenolic compounds gradually decreased when the particle size increased. The highest amounts of extractives were obtained at higher temperatures, and at 170 and 200 °C, a significant influence from the temperature on the chemical composition was noticed. Namely, the phenol and robinetin yields increased, while the rest of the main phenolic compounds were degraded. Additionally, at higher temperatures (170 and 200 °C), two newly formed furfural compounds were detected.

  • Researchpp 4239-4251Terzi, E. (2018). "Thermal degradation of particleboards incorporated with colemanite and common boron-based fire retardants," BioRes. 13(2), 4239-4251.AbstractPDF

    Fire-resistance and thermal degradation were evaluated for particleboards incorporated with colemanite and common boron-based fire retardants (zinc borate and boric acid:borax mixture). The main purpose of this study was to suggest an alternative fire retardant to be used in particleboards with low cost and considerably lower environmental impact compared to common boron-based fire retardants. For this purpose, the colemanite mineral was chosen as a raw boron mineral because of its good fire performance demonstrated previously in wood-plastic composites. The test compounds were incorporated into the furnish during the particleboard manufacturing process. Fire performance tests and thermal degradation analysis were then performed in the treated particleboard specimens. Mass loss calorimeter tests were applied to determine the oxidative thermal degradation properties of the produced particleboards, whilst thermogravimetric analyses were used to evaluate the non-oxidative thermal behavior of the particleboards. The lowest peak heat release rate and the highest activation energy values were recorded for the boric acid:borax mixture-incorporated particleboards at a loading level of 10%. Overall the results showed that colemanite had a lower fire-retardant property in the particleboards compared to the common boron-based compounds tested in the study.