NC State
BioResources
  • Editorialpp 2249-2251Pal, L., and Joyce, M. (2017). "Paper need not be flat: Paper and biomaterials industries need to converge to bring about true innovation," BioRes. 12(2), 2249-2251.AbstractArticlePDF

    Biomaterials and new processes (3D printing and flexible hybrid electronics) offer opportunities to break free from a 2D paper world by allowing for the development of smart multi-dimensional structures. While there has been recent progress reported in each of these areas of technology, to date, the merger of these technologies has been very limited. We believe that their merger offers boundless opportunities and an opportunity for the paper industry to innovate a low cost, sustainable housing solution capable of promoting the well-being of its occupants while minimizing the environmental impact of its daily use.

  • Editorialpp 2252-2253Hubbe, M. A. (2017). "Why I don't do academic social media...or do I?," BioRes. 12(2), 2252-2253.AbstractArticlePDF

    A communications scholar at our university asked me recently whether I would take part in a debate about academic social media services such as ResearchGate. Yes, I responded, as long as I don’t have to argue the affirmative – that such online systems are necessarily a good thing. Personally I do not count myself as a user of academic social media, but I can easily understand why others could make an opposite decision. Academic social media can provide a way to get copies of full-length published articles, to pose questions to other researchers, to get various questions answered, and in general to foster relationships with well-networked and possibly influential people within one’s academic field. Or, like me, you might just enjoy having something mildly annoying that is fun to complain about.

  • Researchpp 2254-2268Pangh, H., and Doosthoseini, K. (2017). "Optimization of press time and properties of laminated veneer lumber panels by means of a punching technique," BioRes. 12(1), 2254-2268.AbstractArticlePDF

    The impact of veneer punching pattern and density (343, 356, and 1424 hole·m-2) was tested relative to selected physic-mechanical properties of 5-ply laminated veneer lumber (LVL) panels fabricated from poplar wood (Populus deltoides) under different press time (5, 6, and 7 min). Samples were made with urea-formaldehyde resin using hot press technology at a uniform pressure of 10.8 N·mm-2 and temperature of 120 °C. The results indicated that punching the inner veneers (except the core veneer) of LVL significantly improved the average values of shear strength, modulus of elasticity, and bending strength (both parallel and perpendicular to the grain). In contrast to control samples, the veneer punching technique showed an overall negative impact on the water resistance of LVL (after either 2 or 24 h of immersion in water). Nevertheless, specimens with punching densities of 1424 hole·m-2 pressed for a maximum of 5 min were more dimensionally stable than the control samples. The physic-mechanical properties of LVL were significantly affected by presstime as well. Considering the data obtained, the presstime of LVL could be reduced to nearly 16.7%, or 1 min, by using a punching density of 1424 hole·m-2 without any significant negative change in the major physic-mechanical properties.

  • Researchpp 2269-2283Martins, C. E. J., Dias, A. M. P. G., Marques, A. F. S., and Dias, A. M. A. (2017). "Non-destructive methodologies for assessment of the mechanical properties of new utility poles," BioRes. 12(2), 2269-2283.AbstractArticlePDF
    The application of non-destructive technologies for the assessment of mechanical properties has been increasingly used due to its reliable assessment of the condition of timber elements. The application of such methods is well established for sawn timber and small-diameter roundwood. However, regarding the assessment of the mechanical properties for roundwood with larger diameters, which are usually used for new utility poles, a fewer number of studies are available. This research considered three different methodologies for application in Maritime Pine utility poles: i) longitudinal vibration, ii) transverse vibration, and iii) ultrasound. The methodology with better results was chosen for use in the second stage of testing. Furthermore, mechanical tests were performed to compare and validate the results from the non-destructive tests. The moisture contents and densities were also determined. Simple and multiple linear regression analyses were performed between the visual, dynamic, and mechanical properties. The longitudinal vibration method achieved the best correlation within the non-destructive methods, while the ultrasound method had no noticeable correlation. The vibration frequency (f) (r = 0.51) showed a better correlation with the bending strength (MOR) than the dynamic modulus of elasticity (MOEdyn) (r = 0.45). The static modulus of elasticity (MOE) was the best property used to predict MOR because it presented the highest correlation (r = 0.79).
  • Researchpp 2284-2295Zhu, Q. L., Dai, L. C., Wu, B., Tan, F. R., Wang, W. G., Tang, X. Y., Wang, Y. W., He, M. X., and Hu, G. Q. (2017). "Integrated methane and ethanol production from livestock manure and soybean straw," BioRes. 12(2), 2284-2295.AbstractArticlePDF
    Methane and ethanol were co-produced from different feedstock, including a mixture of dairy manure and soybean straw (DMS), a mixture of pig manure and soybean straw (PMS), and soybean straw alone (SS), after anaerobic digestion times of 30 and 60 days in mesophilic conditions. Digesting DMS for 60 days led to the highest methane yield of 115.3 g/kg dry raw feed; however, the lowest ethanol yield of 88 g/kg dry raw feed was observed. After 30 days, SS yielded the lowest methane levels (45.2 g/kg dry raw feed) but the highest ethanol levels (113.5 g/kg dry raw feed). Analysis of the net energy balance showed that the highest net energy balance, 6549 kJ/kg of dry raw feedstock, was achieved from the digestion of DMS for 60 days. Overall, both the type of feedstock and length of digestion time played important roles in the integrated processing of methane and ethanol from livestock manure and straw.
  • Researchpp 2296-2309Chen, Z., and Qu, G. (2017). "Shearing characteristics of corn stalk pith for separation," BioRes. 12(2), 2296-2309.AbstractArticlePDF
    The rind of corn stalk (Zea mays L.) contains a high content of lignin, which is difficult for ruminants to digest. So, the separation of the pith and rind is the basis for the effective use of corn stalk. The shearing characteristics of pith are important parameters in the process of the separation of rind and pith for corn stalk. In this study, both the shearing strength and shearing energy were determined for the pith of cornstalk. The shearing force was measured at three moisture content levels (10 w.b.%, 40 w.b.%, and 70 w.b.%), different sample heights (lower, middle, and upper), and three different shearing speed levels (2 mm·min-1, 20 mm·min-1, and 50 mm·min-1). The shearing strength and the shearing energy were calculated from this data. The shearing energy was calculated by using the area under the shearing force versus the displacement curve. The results showed that the maximum shearing strength and the shearing energy increased as the moisture content increased. The maximum shearing strength and shearing energy were found to be 0.8452 MPa and 0.6446 J, respectively. Both the shearing strength and the shearing energy were found to be higher in the lower region of the stalk due to structural heterogeneity.
  • Researchpp 2310-2325Chen, Y., and Guo, W. (2017). "Nondestructive evaluation and reliability analysis for determining the mechanical properties of old wood of ancient timber structure," BioRes. 12(2), 2310-2325.AbstractArticlePDF

    The objective of this study was to evaluate the mechanical properties of ancient wood of Abies fabri (Mast.) Craib based on the nondestructive tests and reliability analysis. Nondestructive tests including resistograph and stress wave test, and destructive tests were conducted on the wood specimens. Results indicated that there were significant linear correlations between the resistance amplitude (F) and green density (ρ), the dynamic modulus of elasticity (ED) and static modulus of elasticity (MOE), modulus of rupture (MOR), and ultimate compressive strength (UCS) of wood specimens. The cumulative distribution of the predicted MOR and UCS based on the nondestructive tests could be well fitted by the normal distribution according to the χ2 test. Moreover, a reliability analysis program based on the first-order second-moment method was developed. Reliability analysis results showed that the reliability index increased nonlinearly with the increase of the live-to-dead load ratio, and decreased nonlinearly with the increase of the design values for all the simulation load cases. According to the minimum reliability index requirements of the Chinese national standard, it is suggested that the design value of MOR and UCS be 14.0 and 10.7 MPa, respectively.

  • Researchpp 2326-2338Yadav, S. P., Ghosh, U. K., and Ray, A. K. (2017). "Kinetic studies on Pisum sativum waste (pea pod) hydrolysis to furfural," BioRes. 12(2), 2326-2338.AbstractArticlePDF

    To obtain a higher furfural yield from Pisum sativum (pea pod) waste, the effects of the process variables phosphoric acid concentration (wt.%), reaction temperature, and liquid solid ratio (LSR) were investigated. A new reaction scheme was proposed consisting of series and parallel reactions for the formation of furfural. Kinetic models were developed to describe changes in the concentration of furfural with time. A modified Arrhenius equation was used to find out correlations between kinetic coefficients and reaction parameters. A maximum furfural concentration of 5.27 g/L (40.6% yield based on total conversion of pentosans) was obtained using 6% (wt.%) H3PO4 and liquid-to-solid ratio of 1:10 at 160 °C. Reaction parameters such as acid concentration, reaction temperature, and liquid solid ratio had a strong effect on the yield of furfural.

  • Researchpp 2339-2353Esteves, B., Dulyanska, Y., Costa, C., Vicente, J., Domingos, I., Pereira, H., de Lemos, L. T., and Cruz-Lopes, L. (2017). "Cork liquefaction for polyurethane foam production," BioRes. 12(2), 2339-2353.AbstractArticlePDF

    Cork is one of the most important forest products in Portugal. The cork processing industry is highly resource-efficient, and the only residue is cork powder, which is too small for agglomerate production. This work studied the usage of cork powder for the production of added-value products via polyol liquefaction. Liquefactions were performed in a reactor using a mixture of polyethylene glycol (PEG 400) and glycerol as solvents, which were catalyzed by the addition of sulphuric acid. Several cork-to-solvent ratios, reaction temperatures, and reaction times were tested. Polyurethane foams were prepared by combining polyol mixtures with a catalyst, surfactant, blowing agent, and polymeric isocyanate. Mechanical tests of the produced foams were conducted, and compressive modulus of elasticity and compressive stress at 10% deformation were determined. The results show that the best conditions for obtaining high liquefaction yields are as follows: 160 °C for 1 h; glycerol-to-PEG 400 ratio of 1:9; cork-to-solvent ratio of 1:6; and 3% H2SO4 catalyst addition. The Fourier Transform Infrared (FTIR) spectra indicated that the lignocellulosic fractions of the cork were more selectively dissolved during acidified polyol liquefaction than the suberin. With liquefied cork powder using these optimized conditions, it is possible to produce polyurethane foams with desired properties.

  • Researchpp 2354-2366Yu, S., Chen, L., and Yan, Z. (2017). "Graphene/hemin hybrid material as a catalyst for degradation of alkaline lignin with hydrogen peroxide," BioRes. 12(2), 2354-2366.AbstractArticlePDF

    A graphene/hemin (H-GN) catalyst for lignin degradation was prepared by a wet-chemistry method with graphene oxide and hemin. Hemin was absorbed onto the graphene surface through π-π interaction. Graphene served as a supporting material for hemin, providing a large contact area between the active molecules of catalyst and substrate, as well as protecting hemin from self-oxidation and maintaining its active molecules. The H-GN catalyst showed high catalytic efficiency in the degradation of alkaline lignin under gentle conditions. At pH 13.0, the degradation rate was 49.7% with H-GN and H2O2 (mass ratio of H2O2 to lignin of 10:1) under 60 °C, which was higher than 34.9% for non-catalyst degradation. At pH 13.2, it was as high as 92.9 wt.% at 100 °C. The lignin was decomposed into small molecules with styrene as the main final product below pH 13 and with the major products of 4-hydroxy-4-methyl-2-pentanone and bis(2-ethylhexyl) phthalate at pH 13.2.

  • Researchpp 2367-2378Mazáň, A., Vančo, M., and Barcík, S. (2017). "Influence of technological parameters on tool durability during machining of juvenile wood," BioRes. 12(2), 2367-2378.AbstractArticlePDF

    This work examined differences encountered when machining juvenile wood vs. mature wood. Difference in the blunting of the cutting tool when processing types of juvenile and mature wood from pine (Pinus sylvestris L.) and poplar (Populus tremula L.) were studied. The experimental model process included milling at various feed (2.5 and 15 m∙min-1) and cutting speeds (pine 20 m∙s-1, poplar 30 and 60 m.s-1), at various angle geometries (rake angle, cutting edge, and clearance angle). The blunting of cutting edge was measured after milling at 100, 300, and 500 meters on milling machine with the lower spindle. The results showed that milling of juvenile wood gives a longer technical lifetime for cutting instruments than milling of mature wood.

  • Researchpp 2379-2393Theng, D., El Mansouri, N. E., Arbat, G., Ngo, B., Delgado-Aguilar, M., Pèlach, M. A., Fullana-i-Palmer, P., and Mutjé, P. (2017). "Fiberboards made from corn stalk thermomechanical pulp and kraft lignin as a green adhesive," BioRes. 12(2), 2379-2393.AbstractArticlePDF

    The feasibility of incorporating purified kraft lignin, at different concentrations ranging from 5 to 29%, into fiberboards made from corn residues was studied. The lignin was obtained from black liquor, which is a residue of the paper industry. Corn stalk raw material and its thermomechanically produced fiber were characterized in terms of their chemical composition. The physical and mechanical properties of the resulting fiberboards were evaluated. The fiberboards produced following a wet process had good mechanical and water resistance properties that satisfied the requirements of the relevant standards. In addition, a Life Cycle Thinking (LCT) approach suggested that lignin-based fiberboards are environmentally preferable than those based on thermosetting resins.

  • Researchpp 2394-2406Md Shah, A. U., Sultan, M. T. H., Cardona, F., Jawaid, M., Abu Talib, A. R., and Yidris, N. (2017). "Thermal analysis of bamboo fibre and its composites," BioRes. 12(2), 2394-2406.AbstractArticlePDF
    Thermogravimetric analysis and differential scanning calorimetry were used to study the thermal degradation and thermal stability of bamboo powder and its composites (EP-BFC) in a nitrogen atmosphere. The thermal stability of EP-BFC decreased as the bamboo filler-loading increased. Compared with epoxy, bamboo powder had a lower thermal stability, which reduced the thermal stability for the higher filler-loading composites. The addition of glass fibre to the EP-BFC improved the thermal stability of the new hybrid composites. Both the hybrid and non-hybrid composites exhibited similar thermal-induced degradation profiles that had only one mass loss step. However, a noticeable difference between the percentage value of the degradation between both the hybrid and non-hybrid composites showed that the EP/G-BFC hybrids were more thermally stable than the non-hybrid EP-BFC. Different materials experienced different activities, which were clearly shown from the DSC analysis. Bamboo fibre and non-fully cured epoxy exhibit exothermic peaks, while fully cured epoxy exhibits an endothermic peak.
  • Researchpp 2407-2420Tian, X., Wang, B., Wang, B., Li, J., and Chen, K. (2017). "Structural characterization of lignin isolated from wheat-straw during the alkali cooking process," BioRes. 12(2), 2407-2420.AbstractArticlePDF
    To investigate the behavior of lignin during the alkali cooking process with different alkali doses, this work demonstrated the structural characteristics illustrated by spectroscopic analyses. Gel permutation chromatography (GPC) and nuclear magnetic resonance (NMR) indicated that the lignin was composed of typical structures for a grass, generally with S and G units and small amounts of H units. The main substructures present were β-O-4 aryl ether linkages, and there were lower amounts of β-β and β-5 linkages. Alkali treatment conditions had evident effects on the chemical structures and properties of lignin. Moreover, NMR indicated that alkali cooking caused lignin to depolymerize more easily with increasing severity and to condense.
  • Researchpp 2421-2432Pekařová, S., Dvořáčková, M., Stloukal, P., Ingr, M., Šerá, J., and Koutny, M. (2017). "Quantitation of the inhibition effect of model compounds representing plant biomass degradation products on methane production," BioRes. 12(2), 2421-2432.AbstractArticlePDF

    During the steam explosion pretreatment of plant biomass, degradation products are generated, and some of these have inhibitory activity against biogas production. The aim of this study was to investigate and quantify the effect of selected model inhibitory compounds on methane production. The results showed no significant inhibition of methane production by furfural at concentrations below 1 g/L. In addition, the microbial community was able to restore biogas production inhibited by this compound after a certain time. 5 hydroxymethylfurfural was evaluated as a more potent inhibitor, with a significant effect above 0.2 g/L. Both compounds were more effective inhibitors with cellulose as the carbon substrate, probably reflecting higher sensitivity of the cellulolytic step in biogas production. No significant inhibition was observed for the phenolic compounds tested, gallic and tannic acids, at concentrations of up to 2 g/L. Thus, the compounds investigated should not represent a problem for the biogas production involving steam explosion preprocessed plant biomass.

  • Researchpp 2433-2451Dogu, D., Yilgor, N., Mantanis, G., and Tuncer, F. D. (2017). "Structural evaluation of a timber construction element originating from the Great Metéoron Monastery in Greece," BioRes. 12(2), 2433-2451.AbstractArticlePDF
    This study identified the wood species and evaluated the degree of weathering and biological degradation of a historical timber construction element originating from the Great Metéoron monastery in Metéora, Greece. The wood material was provided from the interior side of a balcony that was fully covered with a roof and exposed to outdoor conditions for more than 400 years. The species was identified as Quercus spp. of the white oak group. In the timber element, the physical, morphological, and chemical changes were studied to assess the type and extent of degradation using light microscopy and Fourier transform infrared (FT-IR) spectroscopy. To examine the degree of biological degradation and weathering, the surface layer and inner parts of the specimen were studied separately and compared with a recent wood specimen of the same species. The FT-IR analysis revealed remarkable differences between the surface layer and the inner parts of the historical wooden element. Macroscopic and microscopic investigation indicated that multiple types of degradation caused by weathering, fungi, and insect attacks had occurred in the wood structure. It was finally concluded that the historical timber construction element was in better condition than was expected before the study.
  • Researchpp 2452-2465Luo, L., Jin, Y., Li, M., Hu, L., Li, G., and Liu, Y. (2017). "Adsorption mechanism of anionic groups found in sulfonated mulberry stem chemi-mechanical pulp (SCMP) for removal of methylene blue dye," BioRes. 12(2), 2452-2465.AbstractArticlePDF

    The anionic groups (AGs) present in mulberry stem sulfonated chemi-mechanical pulp (SCMP) were studied relative to the adsorption of methylene blue (MB) dye. Adsorption isotherm experiments were carried out for the unbleached pulp, and for pulp that had been subjected to hydrogen peroxide (H2O2) bleaching. AGs present in the pulps appeared to govern the adsorption of MB. MB adsorption kinetics were evaluated for the bleached pulp. The methylene blue adsorption by SCMP, made from mulberry stems, conformed to the Langmuir adsorption model, which is consistent with a monolayer adsorption process. The adsorption thermodynamics showed that the adsorption process was spontaneous and exothermic. A pseudo-second order kinetic model described the adsorption mechanism of MB by the SCMP made from mulberry stems.

  • Researchpp 2466-2478Togay, A., Döngel, N., Söğütlü, C., Ergin, E., Uzel, M., and Güneş, S. (2017). "Determination of the modulus of elasticity of wooden construction elements reinforced with fiberglass wire mesh and aluminum wire mesh," BioRes. 12(2), 2466-2478.AbstractArticlePDF

    Laminated composite wooden construction elements were produced with 7 layers of Scots pine (Pinus sylvestris L.). Fiberglass wire mesh and aluminum wire mesh, which were used as reinforcement materials, were pressed with polyvinyl acetate (PVAc) and polyurethane-type adhesives between each Scots pine layer. The highest bonding strength values were obtained from laminated control specimens produced with polyurethane adhesive without using support materials (4.98 N/mm2) and laminated control specimens made with polyurethane adhesive without using support materials (4.39 N/mm2), respectively. The modulus of elasticity in bending perpendicular to the glue line values of all the specimens except the laminated control specimens produced with polyurethane adhesive without using support materials (14800 N/mm2) were lower than solid wood (6720 N/mm2). In contrast, in the experiments for the modulus of elasticity parallel to the glue line, the variables (adhesive, intermediary layer materials) used for all experiments and specimens were effective factors. Although the modulus of elasticity in bending parallel to the glue line values of all samples were higher than solid wood (6720 N/mm2), the maximum value was obtained in the laminated control specimens produced with polyurethane adhesive without using support materials (17800 N/mm2).

  • Researchpp 2479-2495Zakikhani, P., Zahari, R., bin Haji Hameed Sultan, M. T., and Majid, D. L. (2017). "Morphological, mechanical, and physical properties of four bamboo species," BioRes. 12(2), 2479-2495.AbstractArticlePDF
    Bamboo among other plants has unique properties and massive variety. The properties of bamboo species vary between species and along their culms. The aim of this study was to investigate the characteristics of four bamboo species: Dendrocalamus pendulus (DP), Dendrocalamus asper (DA), Gigantochloa levis (GL), and Gigantochloa scortechinii (GS), and their three portions (bottom (B), middle (M), and top (T)). The number of fibre strands in vascular bundles and the single fibres extracted from every portion was studied. The distribution of fibres varied along the bamboo culms and between species. The DP species showed the highest water content and water absorption and the lowest mechanical properties. The DA species exhibited the best mechanical and physical properties. Moreover, the bottom portion of every species indicated the highest aspect ratio and tensile properties. The results indicated that before the application of bamboo culms in composite materials, the bamboo species should be characterized so that it can be utilised effectively as a renewable reinforcement in composites.
  • Researchpp 2496-2506Lakshmi Veguta, V., Stevanic, J. S., Lindström, M., and Salmén, L. (2017). "Thermal and alkali stability of sodium dithionite studied using ATR-FTIR spectroscopy," BioRes. 12(2), 2496-2506.AbstractArticlePDF

    Sodium dithionite (Na2S2O4) may have the potential to be used as a reducing agent for the stabilization of glucomannan in kraft cooking for increased pulp yield. However, due to the fact that dithionite decomposes under the conditions of kraft pulping, studies of the effects of dithionite in kraft pulping are non-conclusive; sometimes clearly showing an increased yield, and in other studies no effect at all. The specific conditions influencing dithionite degradation are also unclear. For that reason, this study was conducted to determine the thermal and chemical stability of sodium dithionite with respect to specific factors, such as the pH, temperature, heating time, and the concentration of sodium dithionite solution. The study was performed under anaerobic conditions using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The thermal and alkali stability of the sodium dithionite solution was shown to decrease with increasing temperature, heating time, and concentration of the solution at the alkaline conditions studied. The thermal stability decreased rapidly at weak alkalinity (pH 9) as well as in high alkalinity (pH 14), whereas the sodium dithionite was rather stable at moderate alkalinity (pH 11.5 to pH 13).

  • Researchpp 2507-2527Zhang, L., Wang, Z. W., Wang, Y., and Huang, B. (2017). "Transcriptomic profile of lignocellulose degradation from Trametes versicolor on poplar wood," BioRes. 12(2), 2507-2527.AbstractArticlePDF

    The Trametes versicolor genome is predicted to encode many enzymes that effectively degrade lignin, making it a potentially useful tool for biopulping. However, the wood degradation mechanism of T. versicolor is not clear. To identify the enzymes that contribute to lignocellulose degradation, changes in the T. versicolor transcriptome during growth on poplar wood, relative to growth on glucose medium, were evaluated. Eight hundred and fifty-three genes were differentially expressed, with 360 genes up-regulated and 493 genes were down-regulated on poplar wood. Notably, most genes involved in lignin degradation were up-regulated, including eight lignin peroxidase (LiP) genes. Genes encoding cellulose and hemicellulose degrading-enzymes were mostly down-regulated, including six endo-β-1,4-glucanase genes and three cellobiohydrolase I genes. These results characterized transcriptomic changes related to lignocellulose degradation. This information could be used to develop T. versicolor as a tool to improve the efficiency of lignin degradation or to provide a theoretical foundation for a new paper pulp manufacturing process.

  • Researchpp 2528-2547Adıgüzel, A. O., and Tunçer, M. (2017). "Production and characterization of partially purified thermostable endoxylanase and endoglucanase from novel Actinomadura geliboluensis and the biotechnological applications in the saccharification of lignocellulosic biomass," BioRes. 12(2), 2528-2547.AbstractArticlePDF
    Extracellular endoxylanase and endoglucanase from halo- and thermo-tolerant Actinomadura geliboluensis were produced, purified, characterized, and used in the saccharification of native and pretreated lignocellulosic biomasses. The molecular mass of endoxylanase and endoglucanase were 30 and 38 kDa, respectively. The optimum pH and temperature values for both endoxylanase and endoglucanase activities were pH 6.0 and 60 °C, respectively. They were both stable within a pH range of 4.0 to 8.0 and up to 70 °C. The half-lives of endoxylanase and endoglucanase at 70 °C were calculated as 180 min and 60 min, while their half-lives at 80 °C were detected as 60 min and 50 min, respectively. Both the endoxylanase and endoglucanase obeyed Michaelis-Menten kinetics. The endoxylanase and endoglucanase from A. geliboluensis were strongly inhibited by Hg2+. Endoxylanase was activated by Mg2+ and Ca2+ and endoglucanase was activated by Fe2+ and Ca2+. The potential application of endoxylanase and endoglucanase in saccharification of lignocellulosic biomass was further evaluated. The reduced sugar was 265.12 mg/g biomass after both endoxylanase and endoglucanase were incubated with wheat straw, which was pretreated by 1 % NaOH at 121 °C for 15 min. Endoxylanase and endoglucanase were produced from novel A. geliboluensis, which could potentially be used in biotechnological applications.
  • Researchpp 2548-2564Atnaw, S. M., Sulaiman, S. A., Singh, L., Wahid, Z. A., and Ku Mohammad Faizal Bin Che Ku Yahya , C. (2017). "Modeling and parametric study for maximizing heating value of gasification syngas," BioRes. 12(2), 2548-2564.AbstractArticlePDF

    There are a number of experimental and theoretical studies on the energy conversion of oil palm derivative biomass. Moreover, the potential of this abundant biomass residue for renewable energy in major producing countries in Southeast Asia has been well documented. In this study, the results of an equilibrium model of downdraft gasification of oil palm fronds (OPF), developed using the Aspen Plus chemical process simulator software, and its validation are presented. In addition, an optimization of the major output parameter of importance (i.e., the higher heating value of syngas) with respect to the main operating parameters (i.e., temperature, equivalence ratio (ER), and moisture content) was performed. The response surface method (RSM) was used to determine the mathematical relationship between the response of interest, which was the heating value of syngas, and the operating conditions. This method was used to further determine the conditions that would lead to optimum higher heating values of syngas. Optimum values identified by RSM were: oxidation zone temperature of 1000 °C, moisture content in the range of 4%, and an equivalence ratio of 0.35. These optimum operating conditions and the corresponding higher heating value of syngas were found to correspond with the experimental results.

  • Researchpp 2565-2578Yi, X., Zhao, D., Ou, R., Ma, J., Chen, Y., and Wang, Q. (2017). "A comparative study of the performance of wood-plastic composites and typical substrates as heating floor," BioRes. 12(2), 2565-2578.AbstractArticlePDF

    The thermal properties of wood-plastic composites (WPCs) and typical heating floor substrates heated by an electrothermal film were studied. Their effects on human feelings and the human autonomic nerve system were also investigated. The temperature changes of the specimens during heating and cooling were analyzed with an infrared thermal imager. People’s subjective feelings of touching different materials were analyzed with a semantic differential (SD) technique, and their electrocardiography was recorded with a multi-channel physiological signal acquisition system. The thermal conductivity, temperature variation, tactile impression, and heart rate variability of WPCs and other heating floor substrates were investigated. The WPCs presented a markedly lower thermal conductivity and superior tactile impression compared with ceramic tile, which has a similar density to WPCs. There was a negative correlation between the scores of the warm-cool feeling and the density of the heating floor substrates under room temperature (19 °C ± 1 °C), and a positive correlation when heated (33 °C ± 1 °C). The thermal conductivity and heat storage capacity of WPC were higher than those of solid wood. Electric heating composite floors with a high comfort level and good thermal properties could be manufactured by combining WPCs and solid wood.

  • Researchpp 2579-2591Dumitrascu, A. E., Musat, E. C., Dumitrascu, D. I., Ciobanu, V. D., and Salca, E. A. (2017). "Influence of sessile oak log characteristics on the efficiency in veneer cutting," BioRes. 12(2), 2579-2591.AbstractArticlePDF

    The sessile oak tree represents 10.5% of the forest area in Romania and is the most widespread indigenous oak species. To select the most suitable domain of use for sessile oak wood, certain dimensional and qualitative criteria were taken into consideration. The aim of the present study was to highlight the influence of some log characteristics (wood diameters and quality) on the efficiency in sessile oak veneer cutting. The authors used a group of sessile oak logs purchased from Targoviste in Southeast Romania. The results analysis indicates the influence of sessile oak log diameters on the veneer efficiency comparative with decorative veneer efficiency by estimation of the cumulative density function (CDF). Analyzing the quality of sessile oak logs, it was found that buds and insect holes were the most important defects that appeared. Also, the regression analysis indicates an acceptable level of the present defects and did not have a significant influence to the veneer cutting efficiency, upon the number of obtained veneer sheets and the surface area of special veneer sheets, respectively.

  • Researchpp 2592-2608Ruman, D., Záborský, V., Svoboda, T., Kašičková, V., and Rondrová, V. (2017). "Identifying the characteristics of laminated wood based on the values of deflection measured during its bending," BioRes. 12(2), 2592-2608.AbstractArticlePDF
    This article is aimed at verifying the influence of selected factors (wood species, lamella combination, type of adhesive, number of loading cycles) on the deflection at the proportionality limit YE, deflection at the point of rupture YMOR, and the ratio between the deflection at the proportionality limit and the deflection at the point of rupture YE :YMOR. All of the monitored characteristics were evaluated on test specimens made from lamellas of beechwood (Fagus sylvatica L.) and aspen wood (Populus tremula L.). The laminated wood consisted of a combination of lamellas that were non-densified and densified to 10% and 20% of their original thickness. Two types of adhesives were used for the research: polyvinyl acetate (PVA) glue and polyurethane (PUR) glue. The results create a database of information that can be used in developing materials with specified properties for its intended use.
  • Researchpp 2609-2617Tian, Z., Chen, J., Ji, X., Wang, Q., Yang, G., and Fatehi, P. (2017). "Dilute sulfuric acid hydrolysis of Pennisetum (sp.) hemicellulose," BioRes. 12(2), 2609-2617.AbstractArticlePDF
    Dilute sulfuric acid hydrolysis of Pennisetum (sp.) hemicellulose was investigated in this work. The hemicellulose was obtained by ethanol precipitation of hydrolysate produced via the microwave-assisted H2O2-NaOH extraction from the Pennisetum (sp.). Acid hydrolysis was performed by varying the process parameters, including the sulfuric acid concentration, hydrolysis temperature, solid to liquor ratio, and the reaction time. The xylose yield was selected as the target of process optimization and the orthogonal experiment of L9 (34) was designed to optimize the process conditions. The highest xylose yield of 86.5% could be obtained under the conditions of an acid concentration of 1%, the hydrolysis temperature of 105 °C, a solid to liquor ratio of 1:15, and a reaction time of 4 h. Fourier transform infrared spectroscopy (FTIR) analysis confirmed that most of the hemicellulose had been depolymerized into xylose.
  • Researchpp 2618-2634Čabalová, I., Kačík, F., Gojný, J., Češek, B., Milichovský, M., Mikala, O., Tribulová, T., and Ďurkovič, J. (2017). "Changes in the chemical and physical properties of paper documents due to natural ageing," BioRes. 12(2), 2618-2634.AbstractArticlePDF
    The aim of this study was to assess the changes in chemical and physical properties of selected paper documents, dating from the 18th century to the present date. Paper documents from the 18th, 19th, and 21st centuries had a pH ranging from slightly acidic to alkaline values, whereas paper documents from the 20th century were more acidic. The contents of mannose, glucose, holocellulose, and lignin were significantly correlated with the pH of the paper. High contents of both carboxylic acids (acetic and formic) and the most durable monosaccharide (glucose) were found in the oldest examined paper documents originating from the 18th and 19th centuries. The lowest percentage of brightness was found in paper documents originating from 1920 and 1923. The lowest breaking length was associated with papers originating from 1920.
  • Researchpp 2635-2645Francezon, N., and Stevanovic, T. (2017). "Chemical composition of essential oil and hydrosol from Picea mariana bark residue," BioRes. 12(2), 2635-2645.AbstractArticlePDF

    For the first time, the essential oil of Black spruce (Picea mariana) bark residue was obtained using two types of hydrodistillations: steam distillation (SD) and water distillation (WD). Both gave similar yields and compositions as analyzed using gas chromatography and mass spectrometry. The essential oil composition is turpentine-like with the predominance of α-pinene (40.6% SD; 40.5% WD) and β-pinene (33.9% SD; 25.9% WD), followed by hydrocarbon monoterpenes β-phellandrene (4.8% SD; 3.6% WD), 3-carene (4.1% SD; 3.1% WD), and limonene (4.0% SD; 3.7% WD). Hydrosol’s composition is rich in oxygenated compounds with α-terpineol (29.3% SD; 33.5% WD), trans-pinocarveol (5.2% SD; 3.7% WD), terpinen-4-ol (5.0% SD; 5.8% WD), verbenone (4.9% SD; 5.4% WD), borneol (4.9% SD; 3.9% WD), and pinocarvone (4.6% SD; 4.3% WD). These black spruce bark essential oils differ in composition from those from needles, which are commercially available and rich in bornyl acetate.

  • Researchpp 2646-2659  Tian, Z., Chen, J., Ji, X., Lyo, G., Lucia, L. A., Yang, G. (2017). "Fractionation and characterization of three main components from Pennisetum sinese Roxb. (P. sinese) by microwave-assisted H2O2-NaOH extraction," BioRes. 12(2), 2646-2659.AbstractArticlePDF
    Fractionation of lignocellulosic components is a prerequisite for maximizing valorization of plant biomass in an integrated biorefinery. In this study, microwave-assisted H2O2-NaOH extraction was developed for fractionation of Pennisetum sinese Roxb. (P. sinese), a highly productive energy crop. Different reaction conditions including solid-liquid ratio, NaOH concentration, H2O2 concentration, temperature, and time were tested for their effects on P. sinese fractionation. The cellulose, hemicellulose, and lignin obtained under optimal fractionation conditions were characterized by Fourier transform infrared spectrometry (FT-IR) and nuclear magnetic resonance (NMR). The optimal fractionation conditions were a solid-liquid ratio of 1:25 using 0.5% H2O2 and 4% NaOH at 75 °C for 4 h, which gave cellulose, hemicellulose, and lignin yields of 42.8%, 21.9%, and 15.2%, respectively. FT-IR and NMR analyses of the fractionated components clearly confirmed their structural integrity and representation. The work demonstrates the potential of the alternative approach for efficient fractionation of lignocellulosic biomass components for further valorization.
  • Researchpp 2660-2672Pesenti, H., Torres, M., Oliveira, P., Gacitua, W., and Leoni, M. (2017). "Exploring Ulex europaeus to produce nontoxic binderless fiberboard," BioRes. 12(2), 2660-2672.AbstractArticlePDF
    Ulex europaeus is one of the most abundant and aggressively invasive plants on the world. Its fibres, which can be isolated using an alkaline pulping process, have been successfully thermo-pressed into high-density fibreboards without any type of binder. The influence of the bioorganic and crystalline components on the product was investigated using crystallographic, thermo-analytical, and mechanical techniques. Cellulose was predominantly an Iβ polymorph, more common in hardwood, but the composition of the material was typical of softwood. Both the crystallinity in the fibres and the average domain size of cellulose increased during thermo-pressing. Notwithstanding that the residual lignin was present in a small amount, this promoted the cohesion of fibres by improving hydrolysis and adhesion properties. The best overall properties were observed in the pressed products of 1030 ± 38 kg/m3, showing an elastic modulus of 4.31 ± 0.26 GPa, with a modulus of rupture of 26.5 ± 1.3 MPa. These results serve as the basis to transform the invasive species into a fully non-toxic added-value resource.
  • Researchpp 2673-2689Zaharia, S. M., Morariu, C. O., Nedelcu, A., and Pop, M. A. (2017). "Experimental study of static and fatigue behavior of CFRP-balsa sandwiches under three-point flexural loading," BioRes. 12(2), 2673-2689.AbstractArticlePDF
    Balsa wood is a natural cellular material with an excellent resistance-to-weight ratio that is ideal for manufacturing the core of sandwich structures. In this study, sandwich specimens with a carbon-fiber-reinforced polymer (CFRP) skin and a balsa wood core were tested with static and dynamic loading. Three-point flexural tests in static regime determined the mechanical characteristics of the CFRP-balsa specimens that were needed for subsequent fatigue strength tests. Also, experimental research was performed on the Charpy impact response of the CFRP-balsa sandwich specimens. This study implemented an accelerated fatigue testing method to identify and predict the mean fatigue life of the CFRP-balsa sandwich specimens subjected to cyclic fatigue via three-point flexural tests. Using the accelerated fatigue and the three-point flexural testing methodology on the CFRP-balsa sandwich specimens, the testing period was reduced by 11.9 times, and thus the material costs necessary for the tests were also reduced. Also, the breaking surfaces were analysed to reveal the failure modes of CFRP-balsa specimens subjected to static and fatigue tests at three-point flexural and at impact tests.
  • Researchpp 2690-2698Mertoglu-Elmas , G. (2017). "The effect of colorants on the content of heavy metals in recycled corrugated board papers," BioRes. 12(2), 2690-2698.AbstractArticlePDF

    Recycled paper is an important raw material to provide sustainability of natural resources and reduce the environmental impact of the use of paper from recycled pulp in the packaging industry. Hence, recycled paper production is higher in terms of volume and utilization. Recycled paper products are used in the packaging industry partially or fully. Such usage leads to the presence of heavy metals due to recycled and chemical additive sources. The present study aims at determining the amounts and also identifying the sources of heavy metals such as Pb, Cd, Zn, Ni, and Cu contained in recycled testliner (TL) and fluting (FLT), which are main products used in production of corrugated cardboard. The metals in the structure of the paper used in packages directly or indirectly in contact with foods are heavy metals. Mean values of 2.6 mg kg-1 Pb (lead), 2.8 mg kg-1 Zn (zinc), 0.094 mg kg-1 Cd (cadmium), 1.8 mg kg-1 Ni (nickel), and 25.4 mg kg-1 Cu (copper) were detected in test liner and fluting papers using inductively coupled plasma optical emission spectrometry (ICP-OES). The main sources of heavy metals are colorants, mainly consisting of conventional paint and pigments as well as spot and Pantone Matching System (PMS) colorants.

  • Researchpp 2699-2710Liu, H., Luo, B., Shen, S., and Li, L. (2017). "Design and mechanical tests of FRP pipe with bamboo and veneer layer," BioRes. 12(2), 2699-2710.AbstractArticlePDF

    Pipes that are light in weight are necessary for convenience and to reduce the cost of transportation and installation. A new design of glass fiber reinforced plastic (FRP) pipe with a bamboo and veneer layer is presented in this paper. The core layer of the sandwich structure of the pipe wall is made of bamboo and veneer, and the inner and outer layers are FRP. Range analysis and variance analysis of orthogonal experiments were conducted to investigate the effect of fiber stress, winding angle, and core material on the mechanical performance of the pipes subjected to shearing and parallel-plate loading tests. The results indicated that the new design of FRP pipe with a bamboo and veneer layer was feasible, and the pipe had better mechanical performance with a fiber stress of 300 N, a winding angle of 30°, and a core material of bamboo. Core material was the most influential factor in mechanical performance. The average density of pipes was 0.94 g/cm3, approximately half that of the glass fiber reinforced plastic mortar (GRPM) pipes. The FRP pipe offered advantages in terms of weight savings and improved mechanical performance, and it showed a great application potential for the future.

  • Researchpp 2711-2720Liao, C., Zhang, H., Song, X., Chen, T., and Huang, S. (2017). "The screening method of the internal defects in wood members of the ancient architectures by hammering sound," BioRes. 12(2), 2711-2720.AbstractArticlePDF

    Defects have a serious impact on the load carrying capacity and the safety of ancient architectural wood members. Common screening methods to identify defects cause damage to this wood. To protect ancient architecture, it is necessary to develop a method that can screen for internal defects and estimate their size quickly and efficiently without destruction. This paper studied the detection mechanism of the sound hammering method for screening internal defects in wood. Wood members generated different kinds of vibration through hammering experiments, and the vibration produced by hammering wood with internal-hole defects was divided into three kinds: local surface vibration, the whole structure vibration, and defective-part vibration. The parameters and their variation of these three kinds of vibration were investigated by a mechanical vibration simplified model, and the method for screening the internal defects based on sound hammering was proposed. The feasibility of the method was verified by experiments.

  • Researchpp 2721-2730Büyüksarı, U. (2017). "Effect of loading rate on mechanical properties of micro-size Scots pine wood," BioRes. 12(2), 2721-2730.AbstractArticlePDF

    The use of micro-size samples is becoming more important to determine the mechanical properties of wood. The aim of this study was to investigate the effect of the loading rate on the micro-mechanical properties of Scots pine (Pinus sylvestris L.) wood. The bending strength, modulus of elasticity in bending, compression strength parallel to the grain, and tensile strength parallel to the grain were determined using micro-size test samples. Three different loading rates were used for each test. The first loading rates were determined according to related ISO standards, and the second and third loading rates were determined as half- and quarter- of the standard loading rates. The results showed that the loading rate had significantly affected the modulus of elasticity and compression strength of Scots pine wood. However, the loading rate had no significant effect on the bending and tensile strength of the Scots pine wood. When the loading rate decreased, the mechanical properties of micro-size Scots pine wood were decreased.

  • Researchpp 2731-2747Zhang, B., Leng, E., Wang, Y., Gong, X., Zhang, Y., and Xu, M. (2017). "Characterization of water-soluble intermediates and solid residues from fast pyrolysis of cellulose in a wire-mesh reactor," BioRes. 12(2), 2731-2747.AbstractArticlePDF
    The fast pyrolysis characteristics of cellulose were investigated in a wire-mesh reactor, which minimized the secondary reactions between the solid residues and the evolved volatiles during pyrolysis and facilitated the collection of the primary intermediates and volatiles. The main component of the water-soluble intermediates was anhydro-oligosaccharides with various degrees of polymerization (DP). The yields of cellotriosan and cellotetraosan in the intermediates were much higher than those of levoglucosan and cellobiosan in the early pyrolysis stage, indicating that the depolymerization of the cellulose chain occurred during a random cleavage process. Anhydro-oligosaccharides with DP up to 3, and partially decomposed sugar-ring-containing oligomers, were identified in the primary volatiles. Among the sugar-ring-containing oligomers, the compound with a relative molecular weight of 222 was considered to be the product of a reverse aldolization reaction. An analysis of the solid residues confirmed the occurrence of intramolecular dehydration during the cellulose pyrolysis.
  • Researchpp 2748-2767Yao, X., Xu, K., and Liang, Y. (2017). "Assessing the effects of different process parameters on the pyrolysis behaviors and thermal dynamics of corncob fractions," BioRes. 12(2), 2748-2767.AbstractArticlePDF
    The influence of heating rate, gas flow, and biomass particle size on the pyrolysis and thermal dynamics of corncobs (CC) was investigated experimentally using the quantitative method of thermogravimetric analysis (TGA) coupled with mass spectrometry (MS), and the obtained results were compared in depth. For the examined heating rates of 5, 10, and 20 °C/min, the CC pyrolysis at higher heating rates resulted in a more complete decomposition. The initial pyrolysis temperature decreased when gas flow was increased from 30 to 90 mL/min, whereas the weight loss increased. Particle sizes (d ≤ 74 μm, 74 μm < d ≤ 154 μm, 154 μm < d ≤ 280 μm, and 280 μm < d ≤ 450 μm) had pronounced effects on the thermal decomposition and bio-syngas compounds (CO, CO2, CH4, and H2) distribution. The emission intensities of most the gaseous products increased at the elevated heating rate, while they decreased with increasing gas flow. In sum, the pyrolysis of CC particles of 154 μm < d ≤ 280 μm under 20 °C/min and in a gas flow of 30 to 60 mL/min was the most appropriate for bio-syngas production in industrial applications.
  • Researchpp 2768-2779Li, S., Yang, Q., and Ye, Y. (2017). "Preparation of activated carbon from herbal residues and kinetics of cephalosporin antibiotic adsorption in wastewater," BioRes. 12(2), 2768-2779.AbstractArticlePDF

    In order to utilize the leftover materials from traditional Chinese medicine production and to remove antibiotics from wastewater, extracted herbal residues were used as raw materials to produce activated carbon. To keep a constant quality and adsorption ability across cephalosporin antibiotic samples, all samples were divided into rhizomes, fruits, and leaves to make activated carbon by step-wise carbonization and overheated steam activation. The three kinds of carbon were mixed in the optimal ratio of 5:4:2, which had homogeneity in quality with a high adsorption capacity. Maximum adsorption of the mixture to cefalexin and cefradine were 7.1 mg/g, and the mixture removed 84% of the antibiotics from treated wastewater. Approximately 90% of the antibiotics was desorbed after ultrasonic treatment of the distilled water-carbon mixture for 10 min, and a re-adsorption capacity of 80% was maintained for next use. The adsorption process is dominated by a pseudo-second order kinetic reaction, with two active sites binding to one antibiotic molecule. The rate-limiting step is an intra-particle diffusion process. The isothermal adsorption process conforms to Langmuir and Tempkin isotherm models, showing multilayer and physical adsorption. The activated carbon from herbal residues can adsorb a low concentration of antibiotics in wastewater and be recycled after ultrasonic treatment.

  • Researchpp 2780-2791Hacibektasoglu, M., Campean, M., Ispas, M., and Gurau, L. (2017). "Influence of heat treatment duration on the machinability of beech wood (Fagus sylvatica L.) by planing," BioRes. 12(2), 2780-2791.AbstractArticlePDF
    The comparative behavior of heat-treated and untreated beech wood (Fagus sylvatica L.) were studied in response to planing. Beech wood samples were heat-treated in an electric oven without air circulation, at atmospheric pressure, at 200 °C for 1, 2, 3, 4, 5, or 6 h. After conditioning, both the heat-treated samples and the untreated controls were planed at a rotation speed (n) of 4567 rpm and a feed speed (u) of 10 m/min via a “silent power” cylindrical cutter. The cutting power was measured during machining by a Vellemann DAQ board. After processing, the surface quality was measured along and across the cutting direction with a stylus MarSurf XT20 instrument, and the processing roughness was assessed by the roughness parameter Rk. The influence of the heat-treating duration upon the cutting power and the processing roughness were analyzed and correlated to the mass loss after the heat treatment. Linear regression functions were generated for both of the correlations.
  • Researchpp 2792-2804Moral, A., Aguado, R., Tijero, A., Tarrés, Q., Delgado-Aguilar, and Mutjé, P. (2017). "High-yield pulp from Brassica napus to manufacture packaging paper," BioRes. 12(2), 2792-2804.AbstractArticlePDF

    The stalks that are left on the field after harvesting rapeseed crops could be used to make packaging grade paper. This work evaluates the suitability of mechanical and thermomechanical pulps from rapeseed stalks for papermaking, with a view to alleviating the limitations of recycled fluting. Their performance was compared to that of commercial fluting (recycled fluting) of the same basis weight, 100 g/m2, and to that of virgin pulps from pine wood. The thermomechanical pulp was refined to improve key mechanical properties. Its drainability was found to be very low, even before refining, and its breaking length after beating to 1200 PFI revolutions, 4 km, surpassed that of sheets of recycled fluting that were obtained under similar conditions. These findings support the hypothesis that high-yield pulps from rapeseed stalks are a strong choice of virgin fibres to produce fluting and, generally speaking, packaging paper.

  • Researchpp 2805-2817Čekovská, H., Gaff, M., Osvaldová, L. M., Kačík, F., Kaplan, L., and Kubš, J. (2017). "Tectona grandis Linn. and its fire characteristics affected by its thermal modification of wood," BioRes. 12(2), 2805-2817.AbstractArticlePDF

    After a long absence, tropical wood species are beginning to be applied in the production of interior elements and construction once again. Due to their positive reaction to thermal treatment, they are increasingly subjected to such processes. Tropical hard wood, in spite of some deficiencies of mechanical properties, are still better than softwoods. Another advantage of this wood is its higher durability in comparison with softwoods. However, there is a lack of knowledge about the properties of treated tropical wood species. Specifically, little is known about their reaction to fire, which is necessary in the application of this wood. This study investigated the effects of thermal treatment of Teak (Tectona grandis Linn) wood on selected burning characteristics. Results obtained from raw (untreated) wood test specimens were compared with results obtained from test specimens subjected to thermal treatment at 160 °C, 180 °C, and 210 °C. The monitored characteristics were weight loss and the burn rate. The thermal treatment of teak wood significantly increased its flammability and accelerated its combustion. In addition, its burn rate was higher than in untreated wood, reflecting that it is necessary to add fire retardants to thermally-treated teak wood.

  • Researchpp 2818-2829Zhang, M., Li, Z., and Yang, R. (2017). "Preparation of xylananse loaded biomass-based deinking agents and their application in secondary fiber recycling," BioRes. 12(2), 2818-2829.AbstractArticlePDF

    Recently, biomass-based deinking agents have attracted considerable interest in the pulp and paper industry due to their clean, renewable, and good deinking properties. In this study, the xylanase loaded biomass-based deinking agent (XBD) was prepared with coconut oleic acid, palmitic acid, rosin, and xylanase. The preparation technology of XBD was optimized by an orthogonal test and range analysis. The effects of the moisture content, free alkali, and chelating agent on the enzyme activity of XBD were determined via a single factor experiments. Based on the analysis of the optical and physical properties, the optimum xylanase addition into the biomass-based deinking agent was 15 wt.%, the brightness of the secondary fiber after flotation was 60.2% ISO, and the effective residual ink concentration was 223 ppm.

  • Researchpp 2830-2845Ahmad, Z., Asgher, M., and Iqbal, H. M. N. (2017). "Enzyme-treated wheat straw-based PVOH biocomposites: Development and characterization," BioRes. 12(2), 2830-2845.AbstractArticlePDF

    Valorization of lignocellulosic waste residues in the development of potential biodegradable composites has been of recent research interest. Recent research has shown that wheat straw can be used as a reinforcement material for the synthesis of novel polyvinyl alcohol (PVOH)-based composites. However, certain pretreatment methodology needs to be used for the selective removal of the lignin component. The de-lignification of native wheat straw was performed using an in-house isolated ligninolytic consortium. The bio-composites were developed using the de-lignified wheat straw along with PVOH as the matrix phase and glycerol as a plasticizer via a compression molding technique. In this study, a structural analysis by Fourier transform infrared spectroscopy (FT-IR) showed that the enzymatic treatment led to noticeable changes in the chemical structure of the materials used. A dynamic mechanical analysis (DMA) of the composites revealed an increase in the tensile strength of the sample from 46.1 MPa ± 0.1 MPa to 53.0 MPa ± 0.9 MPa, upon the addition of the plasticizer. Also, there was a noticeable increase in the tensile modulus of composites from 2,130 MPa to 4,520 MPa, respectively. Topographical features of the newly synthesized PVOH-based bio-composites were observed using scanning electron microscopy.

  • Researchpp 2846-2863Withers, J., Quesada, H., and Smith, R. L. (2017). "Bioeconomy survey results regarding barriers to the United States advanced biofuel industry," BioRes. 12(2), 2846-2863.AbstractArticlePDF
    Although the 2005 Environmental Protection Act (EPAct) was enacted to bolster the emerging biofuel industry, 52% of advanced biofuel (AB) projects ended by 2015. However, there are no complete lists of internal and external barriers that can help to explain why these projects are failing. The goal of this study was to develop a list of barriers impeding advanced biofuel projects by conducting a survey of biofuel stakeholders. Based on a literature review and previous research, a list of 23 hypothesized internal and external barriers was elaborated. A survey was conducted to have industry stakeholders provide their perception on the list of hypothesized barriers. The perceptions of industry stakeholders were analyzed by dividing the sample in three different stakeholder groups: advanced biofuel industry members, government representatives, and a third category called others that included publishers, journalists, suppliers, and other related stakeholders to the industry. In addition, nonparametric statistical techniques were used to compare the perceptions of the groups. The most significant results indicated that Technology issues was considered as an internal barrier for the three groups while Funding and Renewable Fuel Standards were perceived as external barriers by the three groups too. In addition, the rating of barriers was further analyzed only by AB industry stakeholders in order to uncover more details on the perception of barriers that might be preventing the AB industry to prosper.
  • Researchpp 2864-2871Jayaseelan, C., Padmanabhan, P., Athijayamani, A., and Ramanathan, K. (2017). "Comparative investigation of mechanical properties of epoxy composites reinforced with short fibers, macro particles, and micro particles," BioRes. 12(2), 2864-2871.AbstractArticlePDF
    The present investigation reports the mechanical properties of banana short fiber, macro particle, and micro particle reinforced epoxy composites. Mechanical properties, such as tensile, flexural, and impact strength, of three different composites were studied and compared based on the three different fiber contents (25 wt%, 30 wt%, and 35 wt%). The composites were prepared by a compression moulding method for which the mixture containing the reinforcing agents and resin matrix was prepare dusing a mechanical stirrer. The scanning electron microscopy (SEM) analysis revealed the failure mechanism and the resulting damage that occurred in the composites. The short fiber composite with 35 wt% content showed the highest tensile strength (35.59 MPa), whereas the macro particle composite with 35 wt% content showed the highest flexural strength (67.16 MPa). In the case of the impact strength, both the short fiber and macro particle composites showed the highest impact strength (0.32 J). The mechanical properties of epoxy composites increased substantially with increase of content of reinforcing agents (short fiber, macro particle, and micro particle).
  • Researchpp 2872-2898Adebisi, G. A., Chowdhury, Z. Z., Abd Hamid, S. B., and Ali, E. (2017). "Equilibrium isotherm, kinetic, and thermodynamic studies of divalent cation adsorption onto Calamus gracilis sawdust-based activated carbon," BioRes. 12(2), 2872-2898.AbstractArticlePDF

    Activated carbon (RSAC) was prepared using the two steps of hydrothermal carbonization (HTC) and chemical activation from the sawdust of Calamus gracilis, commonly known as Rattan (RS). The HTC process was carried out using a Teflon-lined autoclave to produce hydrochar, followed by chemical activation using phosphoric acid (H3PO4). The highest removal percentage obtained for lead, Pb(II), and zinc, Zn(II), cations were 86.71% and 64.26%, respectively, using the initial adsorbate concentration of 350 mg/L at 30 °C. These values strongly indicated the promising adsorption potential of the newly prepared hydrochar-based activated carbon (RSAC) for the better management of industrial wastewater and effluents. The analysis of the equilibrium sorption data revealed that these adsorptions followed the Langmuir isotherm model and the pseudo-second order kinetic model. The adsorption process was endothermic and spontaneous. The prepared carbon (RSCAC) showed enhanced surface area with porous texture, which could effectively aid for elimination of Pb(II) and Zn(II) cations from waste water.

  • Researchpp 2899-2911Yin, Y., Dang, C., Zheng, X., and Pu. J. (2017). "Synthesis of 2-hydroxypropyl trimethylammonium chloride chitosan and its application in bamboo fiber paper," BioRes. 12(2), 2899-2911.AbstractArticlePDF

    To obtain a functional composite paper with antibacterial activity, 2-hydroxypropyl trimethylammonium chloride chitosan (HACC) was prepared and sprayed onto the surface of paper made of bamboo fiber. HACC was synthesized from chitosan with 2,3-epoxypropyl trimethylammonium chloride (GTAMC), and the optimal preparation conditions were selected by single-factor tests. The highest degree of substitution (DS) of HACC reached 0.868, when the ratio of chitosan to GTAMC was 1:4, and the water solubility was noticeably improved. The structural characterization demonstrated the successful modification on the original chitosan with a decrease in heat stability and the peak correlated with hydroxypropyl trimethylammonium chloride groups in FTIR. The addition of HACC in the bamboo fiber paper greatly increased the antibacterial activity, and water absorption was higher as well. These results may serve as a basis for the modification and the preparation of chitosan antibacterial agents.

  • Researchpp 2912-2929Wonnie Ma, I. A., Shafaamri, A., Kasi, R., Zaini, F. N., Balakrishnan, V., Subramaniam, R., and Arof, A. K. (2017). "Anticorrosion properties of epoxy/nanocellulose nanocomposite coating," BioRes. 12(2), 2912-2929.AbstractArticlePDF

    Nanocellulose (NC) is an attractive reinforcement agent that can be incorporated into protective coatings because it is a renewable, biodegradable, and biocompatible polymer resource. In this study, a series of epoxy resin-based nanocomposites were prepared in the form of coatings with various amounts of NC loadings, and the coatings were applied onto mild steel at room temperature. The characterizations of the NC and nanocomposites were performed via X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR). The thermophysical properties of the nanocomposites were evaluated using differential scanning calorimetry (DSC) and thermogravimetry (TGA) analyses. The transparency of the nanocomposite specimens was examined by ultraviolet visible (UV-Vis) spectroscopy in the range of 300 to 800 nm. The corrosion protection properties of the coated mild steel substrates immersed in a 3.5% NaCl solution were studied comparatively by electrochemical impedance spectroscopy (EIS). The results showed that all of the nanocomposite coatings with NC noticeably influenced the epoxy-diamine liquid pre-polymer, both physically and chemically. Furthermore, the 1 wt.% NC nanocomposite coating system was found to have the most pronounced anti-corrosion properties, as confirmed by a 30-day EIS study.

  • Researchpp 2930-2940Luo, G., Zhang, L., Chen, T., Yuan, W., and Geng, Y. (2017). "Butyric acid fermentation in xylose and glucose by Clostridium tyrobutyricum," BioRes. 12(2), 2930-2940.AbstractArticlePDF

    The objective of this study was to understand the effect of different concentrations of xylose and glucose on butyric acid production by Clostridium tyrobutyricum. C. tyrobutyricum was cultured in a medium containing xylose, glucose, or mixtures of xylose and glucose as the main carbon source. The butyric acid concentration increased from 3.5 to 16.3 g/L in the xylose media, and from 2.6 to 27.0 g/L in the glucose media when the initial sugar concentration increased from 5 to 75 g/L. The yield from xylose to butyric acid started to decrease as the sugar concentration was above 35 g/L, while for glucose media higher glucose concentration resulted in higher yield. At low sugar concentrations (5 g/L or 15 g/L), xylose was more efficient than glucose for butyric acid generation, but at high concentrations (55 or 75 g/L), glucose was more efficient. In mixtures containing both sugars, glucose was the preferred sugar for bacteria growth and xylose was rapidly consumed only after the glucose was exhausted. The xylose to glucose ratio affected bacterial growth and butyric acid production. High xylose to glucose ratios (4:1 or 3:2) showed better butyric acid production than low ratios (1:1, 2:3, or 1:4) when the total initial sugar content in the media was kept at 30 g/L.

  • Researchpp 2941-2954Shin, S., Park, S., Park, M., Jeong, E., Na, K., Youn, H. J., and Hyun, J. (2017). "Cellulose nanofibers for the enhancement of printability of low viscosity gelatin derivatives," BioRes. 12(2), 2941-2954.AbstractArticlePDF

    Inadequate rheological properties of gelatin methacrylamide (GelMA) were successfully improved by incorporating cellulose nanofibers (CNFs), such that the printed scaffolds could maintain their structural fidelity during the three-dimensional (3D) bio-printing process. The CNFs provided an outstanding shear thinning property, and the GelMA/CNF inks exhibited high zero shear viscosity and structural fidelity under a low dispensing pressure. After evaluating the printability, composite inks containing 2% w/v CNF were observed to have an optimal concentration of CNF to prepare 3D print stable constructs. Therefore, these inks were used to manufacture human nose and ear structures, producing highly porous structures in the printed composite hydrogels. Furthermore, the mechanical stability of the GelMA/CNF composite hydrogel was increased when CNFs were incorporated, which indicated that CNFs played an important role in enhancing the structural properties of the composite hydrogels. Additionally, the biocompatibility of CNF-reinforced hydrogels was evaluated using a fibroblast cell line.

  • Researchpp 2955-2964Vázquez, B. C., Roa-Morales, G., Natividad, R., Balderas-Hernández, P., and Saucedo-Luna, J. (2017). "Thermal hydrolysis of orange peel and its fermentation with alginate beads to produce ethanol," BioRes. 12(2), 2955-2964.AbstractArticlePDF

    Orange peel (OP) was subjected to thermal hydrolysis at temperature (T) and pressure (P) values lower than 180 °C and 1000 kPa, respectively, to minimize the energy consumption and obtain a good ethanol yield. The process was conducted in an autoclave, a pressurized reactor for studying the effect of T (120 to 180 °C), P (500 to 1000 kPa), gas type (N2 or CO2), and OP loading (2.5 x10-2 and 5 x10-2 gmL-1) on the reducing sugars yield. The results were compared with those from acid hydrolysis. Hydrolysates were fermented using immobilized yeast on alginate beads, and the highest ethanol yield of 33.14 g/L was obtained from OP treated at 120 °C. Under these conditions, a minimum of 1,407 kWh energy consumption was achieved.

  • Researchpp 2965-2981Zhang, S., Lu, J., Li, M., and Cai, Q. (2017). "Efficient production of furfural from corncob by an integrated mineral-organic-Lewis acid catalytic process," BioRes. 12(2), 2965-2981.AbstractArticlePDF
    An M-O-L acid (mineral acid, organic acid, and Lewis acid)-catalyzed integrated process for furfural production from corncob was proposed to improve corncob conversion and furfural selectivity. First, the co-catalysts of sulfuric acid and acetic acid were investigated for their impact on furfural production. Sulfuric acid as a pretreatment catalyst was mixed with corncob before the experiment. Acetic acid, which is a byproduct of hemicellulose hydrolysis, was fed together with steam. The results showed that the cooperation of sulfuric acid and acetic acid decreased the total acid consumption dramatically. FeCl3·6H2O was also investigated as a co-catalyst in an effort to enhance the conversion of xylose to furfural and decrease furfural degradation. The integrated catalytic process achieved the highest furfural yield of 68.04% through the use of M-O-L acid under a reaction temperature of 180°C, 3v% acetic acid, 4.0 wt.% sulfuric acid of 0.6 mL/g liquid to solid ratio, and 5 g FeCl3·6H2O per 100 g of biomass.
  • Researchpp 2982-2990Kim, E. H., Lee, J. Y., Kim, C. H., and Park, T. U. (2017). "Effect of carrier chemicals on the optical properties of paper surface-sized with fluorescent whitening agents," BioRes. 12(2), 2982-2990.AbstractArticlePDF
    Fluorescent whitening agents (FWAs) are important chemicals for improving the CIE whiteness and ISO brightness of papers. However, papermakers must reduce the amount of FWAs added to their products because FWAs present many disadvantages associated with the papermaking process, as well as paper quality; the public also has concerns about these chemicals in papers. Because the first step to reducing FWAs in the papermaking process is to improve their whitening effect, a new strategy for the effective use of FWA carrier chemicals must be developed. In this study, the whitening effects of tetra-sulpho FWA (T-FWA) and hexa-sulpho FWA (H-FWA) are compared in surface sizing, as well as with carrier chemicals. H-FWA showed a greater whitening effect than T-FWA in surface sizing, and carrier chemicals improved the optical properties of the paper when surface-sized with FWAs. It is concluded that carboxymethyl-celluloses (CMCs) were a more effective carrier chemical for T-FWA; polyvinyl alcohol (PVOH) is effective with H-FWA in the surface-sizing process to increase paper sheet whiteness.
  • Researchpp 2991-3000Li, X., Wang, X., and Zhang, M. (2017). "An investigation of the drying rate of water in wood at different relative humidities studied by time domain nuclear magnetic resonance," BioRes. 12(2), 2991-3000.AbstractArticlePDF

    The wood drying rate was determined at five different relative humidities (RHs) using time domain nuclear magnetic resonance (TD-NMR). The objective of this study was to obtain the drying rate of bound water and free water, and to also build a relation between RH and drying rate. Two kinds of wood species, Qingpi poplar (Populus platyphylla var. glauca) and Pinus sylvestris var. mongolica Litv. were employed for the spin-spin relaxation time (T2) measurement. The mass of free water and bound water during drying were obtained at the same time. The results indicated that the poplar specimens had a higher fiber saturation point (FSP). For both wood species, free water decreases quickly, which contributes to the main drying, especially at the beginning of drying, and still exists even when the moisture content (MC) is below the FSP. Bound water decreases slowly, and its equilibrium content ranges from less than 10% to more than 20%, in the order from lower RH to higher RH. In addition, the drying rate decreases linearly with increasing RH.

  • Researchpp 3001-3016Magoling, B. J. A., and Macalalad, A. A. (2017). "Optimization and response surface modelling of activated carbon production from mahogany fruit husk for removal of chromium (VI) from aqueous solution," BioRes. 12(2), 3001-3016.AbstractArticlePDF

    The use of activated carbon (AC) from lignocellulosic wastes has gained a lot of research interest because of its great economic and environmental value. In this work, AC was prepared from mahogany fruit husk (MFH) via chemical activation with phosphoric acid and heat treatment. The relationships among the activation parameters H3PO4%, heating temperature, and holding time, and their effect on chromium (VI) removal, were investigated using the response surface method (RSM), following a central composite design (CCD). The optimized activation conditions resulted in a 92.3% Cr6+ removal efficiency for a 50 mg/L Cr6+ aqueous solution. The surface properties of the optimized MFHAC were investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared (FTIR) spectroscopy, and nitrogen adsorption/desorption studies. The MFHAC prepared under the optimized conditions had a high surface area (SBET) of 1130 m2/g, with a well-developed porous structure. The equilibrium data of Cr6+ adsorption onto the MFHAC was best fit by the Langmuir isotherm model, while the adsorption kinetic data followed the pseudo-second order kinetic model. Hence, MFHAC proved to be an efficient technology for removing Cr6+ from simulated wastewater.

  • Researchpp 3017-3029Hong, S., Lian, H., Pan, M., and Chen, L. (2017). "Structural changes of lignin after ionic liquid pretreatment," BioRes. 12(2), 3017-3029.AbstractArticlePDF

    Changes of lignin’s structure were investigated resulting from an ionic liquid ([Bmim]Cl,1-butyl-3-methylimidazolium chloride salt) pretreatment. The purified lignin was pretreated by [Bmim]Cl under the following conditions: the ionic liquid to lignin mass ratio was 10:1, the temperature was 85 °C, and the processing time was 2 h and 4 h. The chemical structure of lignin was studied via Ultraviolet (UV) spectra, Fourier Transform infrared (FT-IR) spectra, Nuclear Magnetic Resonance Spectroscopy (13C-NMR), Gel Permeation Chromatography (GPC), X-ray photoelectron spectroscopy (XPS), and Thermogravimetric Analysis (TG). The total content of phenolic hydroxyl increased with increased time. Moreover, the contents of [OHI] and [OHII] (types of phenolic hydroxyl groups) groups were disproportionately increased. The main structure of lignin still was present after the [Bmim]Cl pretreatment. The β-O-4 linkages were broken apart. The degree of lignin degeneration increased with increased time, after being pre-treated with [Bmim]Cl. Simultaneously, a condensation reaction also took place during the pretreatment. Understanding the chemical changes to wheat straw lignin during an ionic liquid pretreatment provides an important theoretical basis for its further industrial use.

  • Researchpp 3030-3042Tanninen, P., Ovaska, S. S., Matthews, S., Mielonen, K., and Backfolk, K. (2017). "Utilization of production-scale machine in experimental fiber material convertibility testing using a novel press-forming tool set," BioRes. 12(2), 3030-3042.AbstractArticlePDF

    The convertibility of paperboard in a press-forming process was studied using a novel type of tool set that allows forming of small substrates such as laboratory handsheets (i.e. experimental materials) to investigate the role of mold design on substrate-press-tool interaction. The tool set makes it possible to prepare rectangular trays in both sliding and fixed blank modes in a pilot-scale press-forming machine. The tests showed that the fixed-blank mode makes it possible to estimate the elongation of the substrate in the forming process by determining the maximum forming depth for rupture-free samples. A more detailed inspection with an optical microscope of grid-patterned materials revealed that elongation took place mostly on the rim area in addition to the tray wall, and that the outer dimensions of the blank remained practically unchanged. The behavior of the material in press forming process was evaluated in addition to the novel tool set in a bigger, production-scale mold, and results showed good agreement between the small tool set and the standard mold, in spite of the dimensional differences. The smaller size of the mold did not require a compromise in any aspect of the press-forming process.

  • Researchpp 3043-3056Liu, B., Qian, S., Dai, H., and Ren, H. (2017). "Separation of cell wall components by kraft pulping and their utilization for oil absorption," BioRes. 12(2), 3043-3056.AbstractArticlePDF
    In the conventional pulp and papermaking process, lignin in black liquor is mostly burned for energy. It has not been widely used as a functional polymer. To use both cellulose and lignin component, unique kraft cooking conditions were used in bamboo cooking in this study, and acid precipitation was used to extract lignin from the black liquor. Under different pH values, the precipitated lignins were characterized and compared by gel permeation chromatography (GPC), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR). Lignin dissolution in acidic conditions was studied. Pulps with high lignin content were used to synthesize oil absorption materials, which were prepared by grafting butyl methacrylate (BMA) onto the cellulose chain. Sodium silicate was used as an initiator, and 1,4-butane dioldimethacrylate (BDDMA) was used as a crosslinker. The structures of grafted copolymers were characterized by FTIR, scanning electron microscopy (SEM), and thermogravimetry (TG). The acid precipitation process was found to be effective and has important implications for the further lignin applications. The grafting reaction between pulps and BMA was successful. The silicone oil absorption capacity of the obtained materials was 15.3 g/g.
  • Researchpp 3057-3066Yao, M., Yang, Y., Song, J., Yu, Y., and Jin, Y. (2017). "Melamine formaldehyde modified furfurylation to improve Chinese fir's dimensional stability and mechanical properties," BioRes. 12(2), 3057-3066.AbstractArticlePDF
    Melamine formaldehyde modified furfurylation (MFMF) was developed in this investigation to overcome the issues encountered by traditional wood furfurylation, the strong acidic reaction condition and the high cost of furfuryl alcohol. In this study, the optimum ratio of melamine, formaldehyde, and furfuryl alcohol constituents and the optimum curing conditions were explored. Then, MFMF was applied to Chinese fir modification and its performance was evaluated by the weight gain rate (WGR), equilibrium moisture content (EMC), dimensional stability (anti-swelling efficiency [ASE]), and parallel-to-grain compressive strength. The results showed that MFMF took place at a pH close to neutral (6.8) and the formulas had good penetration of cell walls. The best stability and improvement to mechanical properties achieved by MFMF were: a WGR of 158.9%; a low EMC of 11.5% under 96% relative humidity conditions; an ASE in high humidity and water-soaked conditions of 58.5% and 64.2%, respectively; and an increase in parallel-to-grain compressive strength by 81.9%, when compared with the control.
  • Researchpp 3067-3075Kesik, H. I., Özkan, O. E., and Öncel, M. (2017). "Characteristics of a protective layer on oil heat-treated Scots pine and fir wood," BioRes. 12(2), 3067-3075.AbstractArticlePDF
    Effects of natural weathering were studied relative to the adhesion strength, surface hardness, and color change of coated heat-treated and untreated Turkish fir and Scots pine wood. For this study, water-based coatings (varnish and paint) were applied on heat-treated samples. The coated heat-treated, and untreated samples were naturally weathered for one year. The difference between several properties such as adhesion strength, hardness, and color were measured before and after weathering. The test results showed that varnished heat-treated samples had good performance as compared to those of the untreated samples.
  • Researchpp 3076-3087Ibrahim, N., Ab Wahab, M. K., Ngoc Uylan, D., and Ismail, H. (2017). "Physical and degradation properties of polylactic acid and thermoplastic starch blends - Effect of citric acid treatment on starch structures," BioRes. 12(2), 3076-3087.AbstractArticlePDF

    The physical and degradation properties of polylactic (PLA)/thermoplastic starch (TPS) blends after TPS modification with citric acid (CA) were investigated. The interfacial adhesion between the PLA and TPS was expected to improve, thus enhancing the physical properties of the PLA/TPS blends. The tensile strength and Young’s modulus for PLA/TPS blends at (60/40) and (40/60) blends ratio were found to increase after modification with CA. On the other hand, the elongation at break of the (60/40) blend decreased, while elongation at break of the (40/60) blend increased. Meanwhile, an additional peak at 1721 cm-1 was detected by the FTIR spectroscopic analysis, which indicated that the TPS had chemically interacted with the CA. The biodegradability properties of PLA/TPS blends were also improved after treatment with CA. The deterioration of PLA/TPS blends was attributed to the incorporation of CA; O2 from the soil was attracted to the PLA/TPS blends, thus speeding up the degradation process of the blends.

  • Researchpp 3088-3107Carvalho, D. M., Queiroz, J. H., and Colodette, J. L. (2017). "Hydrothermal and acid pretreatments improve ethanol production from lignocellulosic biomasses," BioRes. 12(2), 3088-3107.AbstractArticlePDF

    Hydrothermal and acid pretreatments using different acid charges (1.5%, 3.0%, and 4.5% H2SO4) were proposed for eucalyptus, sugarcane bagasse, and sugarcane straw prior to their bioconversion into ethanol using the semi-simultaneous saccharification and fermentation (SSSF) process. The hydrothermal and acid pretreatments were efficient for hemicelluloses removal from eucalyptus (63 to 96%), bagasse (25 to 98%), and straw (23 to 95%) and to remove a substantial amount of lignin from eucalyptus (10 to 34%) and bagasse (10 to 27%). During pretreatments, pseudo-extractives and pseudo-lignin were generated from biomasses. The SSSF was performed in pretreated biomasses using 24 h presaccharification followed by an additional 10 h of simultaneous saccharification and fermentation (SSF). With hydrothermal pretreatment, the eucalyptus presented the highest ethanol production, but only low values for SSSF parameters were obtained, as follows: ethanol yield (0.017 g ethanol/g biomass), volumetric productivity of ethanol (0.16 g L-1 h-1), and ethanol concentration (1.6 g L-1). On the other hand, using acid pretreatment, the straw (pretreated using 4.5% H2SO4) presented the highest ethanol production among the biomasses, assessed based on ethanol yield (0.056 g ethanol/g biomass), volumetric productivity of ethanol (0.51 g L-1 h-1), and ethanol concentration (5.1 g L-1).

  • Researchpp 3108-3121Lyu, S., Lyu, D., Du, G., and Yang, Y. (2017). "Apple branch decomposition and nutrient turnover in the orchard soil," BioRes. 12(2), 3108-3121.AbstractArticlePDF

    Changes in the physical structure and nutrients contents of apple branches were explored after decomposition, and the soil quality of an orchard was evaluated after returning apple branches in situ. Scanning electron microscopy, X-ray diffractometry, and Fourier transform infrared spectroscopy were used to analyse the structural changes of the experimental material. The results showed that the structure of this material is obviously destroyed in the transverse sections and longitudinal sections. Collapsed cell walls had a negative effect on complete branches, which presented sharp decreases in cellulose contents and the partial removal of lignin and carbohydrate contents by the third year. In a final analysis of the nutrients in the branches, there was an obvious decline in macroelements (e.g., phosphorus and potassium), whereas manganese, which is a limiting factor, increased by 4-fold compared with the control. The results indicated that the addition of mulch from branches can be used to maintain a high soil quality in the third year of decomposition.

  • Researchpp 3122-3132Sadatnezhad, S. H., Khazaeian, A., Sandberg, D., and Tabarsa, T. (2017). "Continuous surface densification of wood: A new concept for large-scale industrial processing," BioRes. 12(2), 3122-3132.AbstractArticlePDF

    Fast growing and low-density species can be modified by various thermo-hydro-mechanical (THM) treatments. Wood densification is one of the promising techniques for broadening the application of these species. This study focuses on the use of a high-capacity continuous pressing technique that considerably increases the density in the region beneath the surface of poplar wood. Prior to densification at 185 °C, a softening stage was implemented, with water spraying followed by heating at a temperature of 205 °C to 235 °C. The density profile, set-recovery, and morphology of the densified surface were investigated. Densitometry revealed that an M-shaped density profile was created through the thickness, with a peak density of approximately 700 kg/m3 close to the surfaces. The set-recovery after three wetting-drying cycles was 44%, which revealed that partial stress relaxation occurred during the densification. Scanning electron microscopy (SEM) confirmed that both sides of the wood were successfully densified and that after the wetting-drying cycles, the deformed cells did not completely recover.

  • Researchpp 3133-3142Chen, M. L., Wang, C. G., Fei, B. H., Wu, H., and Zhang, S. Y. (2017). "Corrugating medium made from solid waste of bamboo paper sludge," BioRes. 12(2), 3133-3142.AbstractArticlePDF

    Corrugating medium was made from the solid waste of bamboo paper sludge and old corrugated container (OCC) pulp. The medium also incorporated additions of anion polyacrylamide as a retention agent and cationic starch as a strengthening agent. The estimated molecular mass of anion polyacrylamide, the addition level of anionic polyacrylamide, and the addition level of cationic starch were optimally designed using single-factor analysis. On this premise, the optimum addition level of the solid waste of bamboo paper sludge was found. The best process conditions for the corrugating medium included a base weight of 120 g/m-2, 10 wt.% bamboo paper sludge solid waste, 0.3 wt.% APAM (Estimated molecular mass of 600 × 104 Daltons), and 1.5 wt.% cationic starch. The apparent density, breaking length, and ring crush index were 0.53 g/cm-3, 2.51 km, and 7.48 N/mg-1, respectively, under the best process conditions. This finding could help satisfy the demand for materials used for making the corrugating medium and could support the full utilization of the solid waste of bamboo paper sludge to achieve higher value.

  • Researchpp 3143-3153Asad, M., Brahim, M., Ziegler-Devin, I., Boussetta, N., and Brosse, N. (2017). "Chemical characterization of non-saccharidic and saccharidic components of rapeseed hulls and sunflower seeds," BioRes. 12(2), 3143-3153.AbstractArticlePDF

    The main compositional characteristics of rapeseed hulls (RH) and sunflower shells (SS) were examined in terms of non-cellulosic components. The non-sugar fractions were analyzed by solid nuclear magnetic resonance (NMR) and pyrolysis-gas-chromatography/mass spectrometry (Pyr-GC-MS). Unlike SS, RH is a non-lignified biomass. The presence of large amounts of catechol and cresol suggested the presence of phytomelanin in both materials. Sugars accounted for 60% of RH and 45% of SS. Pectic compounds were extracted from the holocellulose of RH with ammonium oxalate or with citric acid, with 17% and 31% yield, respectively. A glucuronoxylan was isolated from the holocellulose of SS in basic conditions with 16% yield.

  • Researchpp 3154-3165Guo, T., Wang, Y., and Huang, J. (2017). "The effect of pH on electroless Ni-Fe-P alloy plating on poplar veneer," BioRes. 12(2), 3154-3165.AbstractArticlePDF

    Ni-Fe-P alloy coating was fabricated on poplar veneer substrates by an electroless plating method. The influence of pH on coating structure, elementary composition, thickness, crystal structure, surface resistivity, and magnetism were evaluated. The results indicated that when the plating solution pH was 9.5, the Ni-Fe-P coating had a crystal structure. The coating consisted of lamellar metal particles, and the thickness increased to 111 μm. This plated veneer showed soft magnetic properties. In contrast, when the plating solution pH was 4.5, the Ni-Fe-P coating had mainly an amorphous structure. The coating consisted of spherical metal particles, and the thickness was 67 μm. After 600 °C heat treatment, this plated veneer shifted to a crystalline structure and exhibited soft magnetic properties. In two kinds of plated veneers, the lateral direction resistivity was two times greater than the longitudinal direction resistivity.

  • Researchpp 3166-3181Dixon, P. G., Malek, S., Semple, K. E., Zhang, P. K., Smith, G. D., and Gibson, L. J. (2017). "Multiscale modelling of moso bamboo oriented strand board," BioRes. 12(2), 3166-3181.AbstractArticlePDF
    The modulus of elasticity (MOE) of three-layer moso bamboo (Phyllostachys pubescens Mazel) Oriented Strand Board (OSB) was modelled using a multiscale approach proposed for wood OSB. The modelling approach for wood OSB was adapted to bamboo OSB by accounting for the different structures of wood and bamboo tissue. The MOE of moso bamboo OSB was measured previously in bending; the strands in the surface layer had a preferred orientation and were either from the internode region of the culm or contained node tissue. The model for loading parallel to the preferred orientation of the surface strands gives a good description of the measured values of MOE for boards with internode surface strands (8.6 GPa modelled compared to 8.1 GPa previously measured), but overpredicts that for boards with surface strands containing nodes (8.8 GPa modelled compared to 6.7 previously measured). The model for loading perpendicular to the preferred orientation of the surface strands gives a good description of the MOE data if the core layer moduli are estimated using compliance averaging, for specimens with and without nodes (1.5 GPa modelled compared to 1.5 GPa previously measured).
  • Researchpp 3182-3191Qin, C., Li, S., Jiang, G., Cao, J., Guo, Y., Li, J., Zhang, B., and Han, S. (2017). "Preparation of flower-like ZnO nanoparticles in a cellulose hydrogel microreactor," BioRes. 12(2), 3182-3191.AbstractArticlePDF

    Flower-like zinc oxide (ZnO) nanoparticles were synthesized with sodium hydroxide and zinc acetate in a cellulose hydrogel microreactor (prepared by the inversion method). The samples were characterized by scanning electron microscopy, EDX, x-ray diffractometry, ultraviolet-visible diffuse reflection spectroscopy, and nitrogen adsorption-desorption. The results indicated that ZnO grows in a flower-like shape in the pores of the cellulose hydrogel. The pure hexagonal wurtzite structures have uniform diameters in the range of 10 nm to 30 nm, surface areas of 39.18 m2/g, and pore volumes of 0.2109 cm3/g. This study also investigated the photocatalytic properties. The nanoparticles have a band gap of 3.23 eV and a 95.2% efficiency for the ultraviolet degradation of rhodamine B over 3 h at room temperature.

  • Researchpp 3192-3210Síkora, A., Gaffová, Z., Rajnoha, R., Šatanová, A., and Kminiak, R. (2017). "Deflection of densified beech and aspen woods as a function of selected factors," BioRes. 12(2), 3192-3210.AbstractArticlePDF
    Effects of selected factors (wood species (Beech, Aspen), degree of densification (10%, 20%), material thickness (4 mm, 6 mm, 10 mm, and 18 mm), and number of loading cycles (0, 10,000)) were analyzed relative to the bendability of densified wood. The monitored characteristics were the deflection at proportional limit (YE), deflection at maximum limit (YP), and their ratio (YE:YP). One of the main causes of unfavorable wood bending is its low deflection under tensile stress parallel to the fiber in comparison to compressive stress in the same direction. From the results it is clear that the deflection at the proportionality limit depended on all monitored factors. The deflection at the yield point was not influenced by cyclic loading, and the ratio of deflection was influenced by material thickness only. Based on this ratio, the moulding properties of material can be identified. There was a strong correlation between the two deflection limits. The results are an important foundation for progress in the production of laminated materials with specific properties for intended use.
  • Researchpp 3211-3221Grandes-Blanco, A. I., Tlecuitl-Beristain, S., Díaz, R., Sánchez, C., Téllez-Téllez, M., Márquez-Domínguez, L., Santos-López, G., and Díaz-Godínez, G. (2017). "Heterologous expression of laccase (LACP83) of Pleurotus ostreatus," BioRes. 12(2), 3211-3221.AbstractArticlePDF

    The heterologous expression of the gene LACP83 (encoding a laccase) from Pleurotus ostreatus in Escherichia coli was characterized. The laccase enzyme activity and kinetics of bacterial growth with an inducer (IPTG) and without inducer were determined. The maximum enzymatic activity was observed at 7 h post induction with a value of 3740 ± 342 U/L, which was similar to that reported for the native strain of P. ostreatus at 144 h of culture. Furthermore, the induction of laccase with IPTG reduced the specific growth rate of recombinant E. coli BL21 by approximately 50%. These results support the use this system for the recombinant production of the enzyme on an industrial scale.

  • Researchpp 3222-3235Yao, X., Xu, K., and Liang, Y. (2017). "Comparative analysis of the physical and chemical properties of different biomass ashes produced from various combustion conditions," BioRes. 12(2), 3222-3235.AbstractArticlePDF
    The ash yield, composition, mineral phases, and other physical and chemical properties of various biomass ashes are dependent on ashing temperature. To fully understand the impacts of biomass species and ashing temperature on the characterization of biomass ashes, three kinds of biomass fuels were treated at different ashing temperatures to produce biomass ashes. Their properties were analyzed by a series of qualitative and quantitative methods, including X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermal gravimetric, and differential thermal analyzer (TG-DTA). The experimental results indicated that as the ashing temperature was raised, the ash slagging tendency could be enhanced. The fused layer on the surface of ash particles was coated with potassium chloride, which was the key reason for the development of severe agglomeration and slagging. Due to the high carbon content and large number of pores in the lower temperature ashes, a low-cost adsorbent could be developed effectively from these carbon materials. The thermal decomposition of all ashes showed a stepwise mechanism. The total weight loss of the same biomass ash decreased with increased ashing temperature, which corresponded well with the phase transitions and thermal reaction sequences.
  • Researchpp 3236-3249Lu, Z., Wang, M., Jia, W., and Zhao, Z. (2017). "Effects of hot air temperature on drying properties of biomass brick during heat treatment," BioRes. 12(2), 3236-3249.AbstractArticlePDF

    The effects of hot air temperature on the drying properties of biomass brick during heat treatment were examined. Biomass brick was dried for 156 h at 30 °C to 80 °C and 50% relative humidity. The results showed that the moisture content and density of the brick during heat treatment were affected greatly by the hot air temperature. The moisture content was affected remarkably by the drying time. Drying shrinkage extents were affected noticeably by the drying time and air temperature. The moisture content and density after drying were decreased with increased time. The compression strength increased with the increased air temperature from 30 °C to 70 °C.

  • Researchpp 3250-3264Ružiak, I., Igaz, R., Krišťák, L., Réh, R., Mitterpach, J., Očkajová, A., and Kučerka, M. (2017). "Influence of urea-formaldehyde adhesive modification with beech bark on chosen properties of plywood," BioRes. 12(2), 3250-3264.AbstractArticlePDF

    The influence of beech bark concentrations as filler in urea-formaldehyde (UF) adhesives was investigated relative to the composite forming process and selected properties of final 5-layer beech plywood. Beech bark was used as filler to lower the wood processing waste production and decrease formaldehyde emissions. A combination of UF adhesives filled with different beech bark concentrations as the adhesive was used. Three different concentrations of beech bark, 15 wt.%, 20 wt.%, and 25 wt.% were used in the experiment. Urea-formaldehyde adhesive filled with 20 wt.% technical flour was used as a reference sample. The effect of the filler was studied via its temperature profile during pressing, mechanical properties in bending, water absorption, thickness swelling, and formaldehyde emissions after pressing. The time needed to reach the temperature between the beech veneers, at least 105 °C, which was equal to the final temperature filler-adhesive-wood matrix cross-linking, was also investigated during the pressing process. The measurements of the free formaldehyde emissions showed that for samples with non-zero bark concentrations there was a decrease of formaldehyde emissions by at least 46%.

  • Researchpp 3265-3276Cao, Y., Song, W., Yang, Z., Chen, Z., and Zhang, S. (2017). "The properties of particleboard made from alkaline-treated wheat straw and methylene diphenyl diisocyanate binder," BioRes. 12(2), 3265-3276.AbstractArticlePDF

    Properties were evaluated for particleboard made from polymethylene polyphenyl polyisocyanate (pMDI) binder and wheat straw treated with sodium hydroxide (NaOH) and ammonia hydroxide (NH3·H2O) solutions. The crystallinity (Xc) of wheat straw and board properties including internal bond strength (IB), thickness swelling after 24 h (24 hTS), modulus of rupture (MOR), and modulus of elasticity (MOE) were investigated. XRD indicated that the crystallinity of wheat straw was increased with the mass fraction range from 1% to 3%, and the bending properties of board were also improved. MOR and MOE were significantly (P < 0.05) improved, and a positive correlation with solution mass fraction was shown. Bending properties, especially MOE, were superior to the requirements in GB/T 4897-2015. IB of NaOH solution treated board was also significantly higher (P < 0.05), but results for IB of ammonia solution treated and 24 hTS for board treated with both solutions failed to meet the standard. Effects of the two solutions were not the same according to a t-test, and the effects of NaOH were better.

  • Researchpp 3277-3288Gao, X., Dong, Y., Wang, K., Chen, Z., Yan, Y., Li, J.,  and Zhang, S. (2017). "Improving dimensional and thermal stability of poplar wood via aluminum-based sol-gel and furfurylation combination treatment," BioRes. 12(2), 3277-3288.AbstractArticlePDF

    Wood modification is an efficient method to improve wood performance and expand the applications of wood material. In this study, a combination modification method of aluminum sol-gel and furfurylation was developed to improve the performance of poplar wood. Wood samples were characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The properties of the treated wood, including thermal stability, water uptake, dimensional stability, and dynamic wettability were also evaluated. The thermogravimetric analysis results indicated that the incorporation of an aluminum-based gel could prevent furfurylated wood from thermal degradation by converting the gel into nano-Al2O3. The aluminum-based sol-gel apparently hindered furfuryl alcohol polymerization and reduced the weight percent gain of the samples; the anti-swelling efficiency of the treated wood was over 57% (with little decrease) due to crosslinking between the wood and aluminum-based gel. The water uptake and hydrophobicity of the modified samples were improved significantly in comparison to the control samples.

  • Researchpp 3289-3302Šprdlík, V., Kotradyová, V., and Tiňo, R. (2017). "Superhydrophobic coating of European oak (Quercus robur), European larch (Larix decidua), and Scots pine (Pinus sylvestris) wood surfaces," BioRes. 12(2), 3289-3302.AbstractArticlePDF

    Plant surfaces provide an unlimited source of systems for the protection of their surface against the outer environment. These systems have continuously improved over the last 400 million years of evolution. Two of the most fascinating properties of these systems are superhydrophobicity and the self-cleaning ability of several plant species. These properties are most often achieved due to the hierarchical structure of the surface in combination with a deposited blend of epicuticular waxes. In this study, a layer of n-hexatriacontane was deposited on wood surfaces via thermal evaporation, and the self-assembly ability was investigated for various wood species with differently machined surfaces. The behavior of wax crystals was observed using scanning electron microscopy (SEM) and confocal microscopy. The impact on wettability was investigated by measuring contact angles and tilt angles. With wax deposition, a significant change of wettability was achieved, which was represented by the transition from hydrophilic to superhydrophobic surface behavior. The self-assembly ability of n-hexatriacontane resulted in an increased contact angle in all observed samples.

  • Researchpp 3303-3315Dušak, M., Jelačić, D., Pirc Barčić, A., and Novakova, R. (2017). "Improvements to the production management system of wood-processing in small and medium enterprises in southeast Europe," BioRes. 12(2), 3303-3315.AbstractArticlePDF
    Small and Medium Enterprises (SMEs) make up over 99% of all industrial enterprises in southeast Europe. A similar percentage of SMEs can be found within southeast Europe’s wood-processing and furniture manufacturing companies. This research aimed to investigate the current situation in the production management systems of SMEs in wood-processing companies in select Southeast European countries and to suggest possible improvements according to the results. A total of 30 small and medium companies from different countries in the region were surveyed to investigate the advantages and disadvantages of their production management systems. This research aimed to propose a model to create better systems within SMEs in the wood-processing branch and, therefore, achieve better production and business results. In addition, a total of 10 experts who work with management systems in wood-processing from the examined countries were surveyed with the same purpose. The Analytical Hierarchy Process (AHP) analysis of experts’ opinions showed that the managers in small and medium enterprises for wood-processing and furniture manufacturing should pay the most attention to the conditions of the market, promotion, marketing, range of products, and product quality.
  • Researchpp 3316-3330Wei, S., Zhu, M., Song, J., and Peng, P. (2017). "Comprehensive characterization of biochars produced from three major crop straws of China," BioRes. 12(2), 3316-3330.AbstractArticlePDF

    Biochars produced from rice straw, corn straw, and wheat straw under different pyrolysis temperatures were comprehensively characterized. The results indicated that the yields of the biochars decreased for all three biochar types with the increase in pyrolysis temperature from 250 °C to 600 °C. In addition, the carbon contents of the biochars increased, and the polar acidic functional groups decreased with the increase of the pyrolysis temperature. The hemicellulose and cellulose components likely decomposed at approximately 300 °C, and more condensed and ordered aromatic carbon structures were formed in the biochars with the increase in pyrolysis temperature. The results also indicated that these three types of biochars showed many similarities in elemental composition and structure. However, some differences were also observed. This work provides important baseline information for the production of biochars from crop residues with desired properties for environmental applications.

  • Researchpp 3331-3339Wang, Y., Tang, C., Liu, Y., Wang, Y., Lin, B., Zhu, H., and Liu, C. (2017). "Improved bleached chemical reed pulp properties using atmospheric high consistency refining," BioRes. 12(2), 3331-3339.AbstractArticlePDF
    The influence of atmospheric high consistency refining (AHCR) on the properties of bleached chemical reed pulp was investigated. Fiber quality, water retention value (WRV), dynamic drainage, and physical properties of handsheets were determined. The results showed that compared with low consistency refining (LCR), AHCR maintained reed pulp fiber length, had lower fines generation, produced more fiber curl and kink, and improved WRV and dynamic drainage. Compared with LCR pulp, the tear index, folding strength, and tensile energy absorption (TEA) of AHCR pulp were increased, while tensile index was maintained at the same value. A mill trial was performed to demonstrate the benefits of using AHCR, which was to improve machine runnability and to enhance the performance of the paper made from reed pulp.
  • Researchpp 3340-3350Li, X., Chen, W., and Dou, L. (2017). "Activated carbon prepared from Alternanthera philoxeroides biomass by one-step K2CO3 activation," BioRes. 12(2), 3340-3350.AbstractArticlePDF
    Activated carbons (ACs) were prepared from Alternanthera philoxeroides (AP) by K2CO3 one-step mixing activation. The effects of the mixing mass ratio of K2CO3 to AP, activation temperature, N2 flow rate, and period on the yield and specific surface area of ACs were investigated. The results showed that the surface area and pore volume of ACs were closely related to activation conditions and that the activation temperature was the main factor influencing the surface area and pore volume. The activation conditions only had a slight effect on the yield of ACs, which varied between 13.5% and 19.5%. The surface area of 1799.8 m2/g was obtained at a K2CO3 to AP mass ratio of 2:1, activation temperature of 900 °C, activation time of 2 h, and N2 flow rate of 60 cm3/min. The surface morphology of ACs were characterized with scanning electron microscopy (SEM), and the recovered K2CO3 was characterized with powder X-ray diffractometry (XRD). The SEM images of the ACs also showed that the activation temperature had an obvious effect on the porous structure.
  • Researchpp 3351-3370Meekum, U., and Wangkheeree, W. (2017). "Designing the epoxy adhesive formulations for manufacturing engineered woods," BioRes. 12(2), 3351-3370.AbstractArticlePDF
    The design of an epoxy adhesive was investigated by a 2K design of experiment (DOE). All the assigned parameters showed no significant effect for both curing and mechanical properties, except for bisphenol A (BPA), which showed a significantly negative effect on the heat distortion temperature (HDT) of the cured samples. Adding dicyandiamine (DICY) into the hardener retarded cure time and also caused an incomplete curing at room temperature. Curing at 110 °C and 150 °C post curing were the optimal conditions and 20 g of DICY with 50 g of triethylenetetramine (TETA) was optimized. Adduct obtained from aliphatic epoxy (RD108, 14.63 g) and TETA (7.71 g) were selected and employed as hardener ingredients. The incomplete crosslinking reaction was the main reason for the inferior properties at high RD108 loadings. The toughening by blending with polycarbonate (PC) was explored, and 5 phr of PC was selected. Limitation of resin/fiber infusion due to high viscosity was observed. Dilution of the solvents using ethyl acetate (EA) and methyl ethyl ketone (MEK) to reduce viscosity was explored. The mechanical properties of the wood samples manufactured from the EA-diluted epoxy were superior to the MEK dilution. The lower boiling point and good solubility of EA were explained.
  • Researchpp 3371-3386Al-Tabib, A. I., Al-Shorgani, N. K. N., Abu Hasan, H., Hamid, A. A., Kalil, M. S. (2017). "Production of acetone, butanol, and ethanol (ABE) by Clostridium acetobutylicum YM1 from pretreated palm kernel cake in batch culture fermentation," BioRes. 12(2), 3371-3386.AbstractArticlePDF
    The viability of most fermentation processes is very much dependent on the cheap fermentation medium used. Palm kernel cake (PKC) is an abundant biomass generated from the palm oil processing industry that can be used as the carbon source for the growth and production of acetone-butanol-ethanol fermentation (ABE) by Clostridia. In this study, ABE production from the fermentation of PKC using Clostridium acetobutylicum YM1 in a batch culture was conducted. The PKC was subjected to treatment with acids (sulphuric and hydrochloric acids), alkali (sodium hydroxide and alkaline peroxide), enzymatic hydrolysis, and hydrothermal treatment (in autoclave). The sulphuric acid-treated PKC (2% SAPKC) method produced the highest concentration of reducing sugars (30 g/L) compared with the other methods applied. The results showed that increasing the concentration of H2SO4 up to 3% decreased the amounts of generated reducing sugars to 20.4 g/L, which is about 32% less. The fermentation of 1%, 2%, and 3% SAPKC resulted in the production of ABE of 1.07, 5.72, and 3.48 g/L, respectively. This study showed that the pretreatment of PKC improved the content of fermentable sugars and subsequently enhanced the production of ABE by C. acetobutylicum YM1. This study also revealed that PKC can be regarded as a potentially low cost substrate for ABE fermentation.
  • Researchpp 3387-3395Hasegawa, M., Kumamoto, T., Okamura, H., Takeuchi, K., Asakura, R., and Matsumura, J. (2017). "Relationship between chemical retention and velocity of air-coupled ultrasonic waves in fire-retardant-treated wood," BioRes. 12(2), 3387-3395.AbstractArticlePDF

    The ultrasonic wave velocities in wood impregnated with a fire-retardant chemical were measured via a non-contact method. An air-coupled ultrasonic wave was made to propagate along the radial direction of the wood. The wave velocities in the wood samples after chemical impregnation were larger than those before impregnation. With increased chemical concentration, the relative changes in the velocities increased to a maximum of 16.3%, and these velocity changes exhibited a strong correlation with the chemical retention. These findings suggest that it is possible to evaluate the uniformity distributions of chemicals in fire-retardant-treated wood via a non-contact and nondestructive method based on air-coupled ultrasonics.

  • Researchpp 3396-3412Zhu, X., Yi, S., Gao, Y., Zhao, Y., and Qiu, Y. (2017). "Mechanical evaluation and XRD/TG investigation on the properties of wooden dowel welding," BioRes. 12(2), 3396-3412.AbstractArticlePDF

    Mechanical properties related to wooden dowel welding were studied using five different moisture content (MC) values. Birch wooden dowels and Chinese larch substrates were used in this study. A 2% MC for the wooden dowels and a 12% MC for the substrates resulted in the highest pullout resistance. A fitting analysis showed that there was a linear relationship between the pullout resistance and the different values of MC. The errors between the calculated values and the test values were less than 10%. The pullout resistance of the wooden dowel welding fit a Weibull distribution. No accurate linear relation existed between the 95% reliability pullout resistance and the different MC values. Chemical analyses were performed separately on the wooden dowel and the welding interface of a wooden dowel sample with 2% MC and a substrate with 12% MC. X-ray diffraction (XRD) analysis revealed that the degree of crystallinity of the welding interface was 75% higher than that of the wooden dowel. Finally, thermogravimetric analysis (TG) illustrated that pyrolysis of the wood components occurred during the wooden dowel welding process.

  • Researchpp 3413-3424Su, X., Liu, L., Zhang, Y., Liao, Q., Yu, Q., Meng, R., and Yao, J. (2017). "Efficient removal of cationic and anionic dyes from aqueous solution using cellulose-g-p(AA-co-AM) bioadsorbent," BioRes. 12(2), 3413-3424.AbstractArticlePDF

    The removal of cationic methylene blue (MB) and anionic acid red 1 (AR1) dyes from aqueous solution was studied using cellulose-g-p(AA-co-AM) bio-adsorbent (CP bio-adsorbent). The CP bio-adsorbent with surface multiple functional groups and macroporous network structure was synthesized via grafting the acrylic acid (AA) and acrylamide (AM) onto cellulose molecules. The adsorption behavior of the bio-adsorbent to dyes in the aqueous solution was studied. The effects of solution pH, temperature, initial dye concentration, and contact time on the adsorption capacity of the bio-adsorbent were investigated. Due to the abundant functional groups and macroporous network structure, the CP bio-adsorbent exhibited remarkable adsorption performance for the removal of type dyes with an equilibrium adsorption capacity of 998 mg·g-1 for MB and 523 mg·g-1 for AR1. The kinetic studies revealed that the adsorption of dyes was exactly described by a pseudo-second-order kinetic model. Comparison with other bio-adsorbents confirmed that the eco-friendly CP bio-adsorbent possessed excellent potential for water purification.

  • Researchpp 3425-3447Zheng, Y., Tao, L., Yang, X., Huang, Y., Liu, C., Gu, J., and Zheng, Z. (2017). "Effect of the torrefaction temperature on the structural properties and pyrolysis behavior of biomass," BioRes. 12(2), 3425-3447.AbstractArticlePDF

    To improve prospects for high-value utilization of biomass, torrefaction pretreatments were conducted at 210, 230, 250, 270, and 300 °C with a reaction time of 30 min. The pyrolysis of torrefied biomass was also performed on a fixed-bed reactor system at 450 °C. The effect of torrefaction temperature on the yield, energy yield, structure, physical-chemical characteristics, and production composition of bio-oil was studied. The torrefaction pretreatment improved the fuel characteristics of pyrolysis products. When the torrefaction temperature was increased, the -OH and C=O contents decreased, the C=C contents increased, the pyrolysis peak temperature decreased, the residual carbon contents noticeably increased, and the Ea value remained in the range of 69 to 129 kJmol-1. The pore volume increased and the crystallinity index decreased due to degradation and recrystallization. The solid yield of pyrolysis biomass decreased sharply in contrast to the liquid yield. When the torrefaction temperature increased, the bio-oil yield decreased from 36.82 wt.% to 20.13 wt.%. The phenol content in the bio-oil markedly increased; however, oxygen-containing compounds such as acids, sugars, and furans, significantly decreased, which indicated that torrefaction pretreatment efficiently improved the quality of the fuel.

  • Researchpp 3448-3462Rashid, B., Leman, Z., Jawaid, M., Ghazali, M. J., and Ishak, M. R. (2017). "Dynamic mechanical analysis of treated and untreated sugar palm fibre-based phenolic composites," BioRes. 12(2), 3448-3462.AbstractArticlePDF

    Phenolic-based sugar palm fibres (SPFs) were used as a filler for composites that were fabricated by hot pressing. The composites were prepared using various volume loadings of SPFs. Dynamic mechanical analysis (DMA) was carried out to evaluate the storage modulus (Eʹ), loss modulus (Eʺ), and tan delta as a function of temperature. The SPFs were treated by seawater for 30 days and a 0.5 alkaline solution for 4 days. The phenolic composites with 30% volume loading of SPFs were used to determine the effect of treatments on the DMA properties of the composites. The obtained results indicate that incorporating a SPF filler notably increased the Eʹ and Eʺ properties and decreased the damping factor of the phenolic composites. Both treatments affected the DMA results. However, the alkaline-treated composites showed higher DMA properties compared with the seawater-treated and untreated fibre composites.

  • Researchpp 3463-3477Ma, P. Y., Shi, S. W., Fan, F. Y., Wang, Y. Q., Zhang, X. W., and Xing, X. J. (2017). "Determination of combustion kinetic parameters and fuel properties of hydrochar prepared from hydrothermal carbonization of bamboo," BioRes. 12(2), 3463-3477.AbstractArticlePDF

    The hydrothermal treatment of bamboo was carried out to investigate the effects of different temperatures (230 °C, 260 °C) and residence times (30 min, 60 min) on the combustion behaviors and properties of hydrochar. The higher heating value (HHV) increased gradually with increasing hydrothermal temperature and residence time, while the energy yield decreased. It was found that 260 °C and 30 min with a HHV of 22.8 MJ/kg and an energy yield of 57.8% were appropriate parameters for the production of hydrochar. The atomic oxygen/carbon ratio indicated that the upgrading process converted the bamboo into fuel that was similar to clean solid fuel with a high energy density. The thermal gravimetric analysis showed that the temperature and the residence time had noticeable impacts on the combustion behavior and the activation energy of hydrochar. The combustion reaction ability and rate were greatly improved when the hydrochar was prepared at temperatures greater than 200 °C. The activated energy value was determined by the model-free methods, of which Kissinger-Akahira- Sunose (KAS), Flynn-Wall-Ozawa (FWO) were the most appropriate for this purpose and resulted in similar values.

  • Researchpp 3478-3489Denes, L., Lang, E. M., McNeel, J. F., and McGraw, B. (2017). "Development of veneer-based corrugated composites, Part 2: Evaluation of structural joints and applications," BioRes. 12(2), 3478-3489.AbstractArticlePDF
    This publication introduces and describes the mechanical properties of a newly developed structural composite using corrugated veneer panels as core material. Prior to this study, rejected hardwood veneers and veneer residues (side-clippings) were converted into three-dimensional panels, and the basic physical and mechanical properties were investigated through the testing of similar, but non-corrugated products. This study focuses on the application of I-joist web elements, although other application possibilities are also mentioned. Different web to web and web to flanges joints were configured and tested for their tension and shear strength resistance. The load-bearing capacity was evaluated using standard structural size prefabricated members. The I-joists that had corrugated web panels showed an improved load carrying capacity under concentrated loads. Buckling failure, which is common in deep straight web panels of oriented strand board (OSB), or plywood, under concentrated loads could not be observed.
  • Researchpp 3490-3503Ratnasingam, J., Ramasamy, G., Ioras, F., and Parasuraman, N. (2017). "Assessment of the carbon footprint of rubberwood sawmilling in peninsular Malaysia: Challenging the green label of the material," BioRes. 12(2), 3490-3503.AbstractArticlePDF

    Rubberwood is an important wood resource for the wood-based industry in Malaysia and the neighboring countries in the Southeast Asian region. Many studies have been conducted to assess rubberwood’s properties and economic viability for value-added wood products manufacturing. However, information on the material’s environmental performance and green labeling is limited. Therefore, the life cycle approach was carried out in this study to evaluate the carbon footprint of rubberwood rough green sawn timber production. A cradle-to-gate approach was applied. The results indicated that the carbon footprint for rubberwood rough green sawn timber production was 52.9 CO2-eq/m3. However, when taking into consideration the carbon footprint of the whole rubberwood sawmilling industry in comparison to the Dark Red Meranti sawmilling industry, it is apparent that the total carbon footprint of the rubberwood sawmilling industry is remarkably higher. This is due to the use of inefficient processing technology, which leads to a high level of wastage on the harvesting site and in the mill. Therefore, this study shows that the green label accorded to rubberwood appears questionable from the perspective of its carbon footprint, and that efforts must be taken to minimize the waste if the material is to achieve a green material status.

  • Researchpp 3504-3520Chen, C., Sun, G., Chen, G., Li, X., and Wang, G. (2017). "Microscopic structural features and properties of single fibers from different morphological parts of the windmill palm," BioRes. 12(2), 3504-3520.AbstractArticlePDF

    The chemical, morphological, physical, and thermal properties of raw materials and single fibers extracted from different morphological parts of windmill palm were examined and comprehensively characterized after an alkali treatment. Leaf sheathes (LS) with the highest cellulose content (52.26%) achieved the most efficient extraction of fibers. Single fibers extracted from the vascular bundles of the windmill palm raw material had a slender shape with a tapering and sealing terminus, with each single fiber possessing a lumen in its cross-section. These windmill palm fibers displayed similar chemical compositions, but they exhibited significant differences in morphological parameters. Leaf blade fibers (LBFs) had the longest length (1240 μm ± 470 μm) and highest aspect ratio (121.39), which presented excellent potential as a reinforced fiber. After the alkali treatment, almost all of the hemicelluloses and lignin were removed, which resulted in increased crystallinity of extracted fibers. Thermogravimetric analysis confirmed LS stability up to 319 °C, which was higher than that of other materials from windmill palm.

  • Researchpp 3521-3529Mirski, R., Boruszewski, P., Trociński, A., and Dziurka, D. (2017). "The possibility to use long fibres from fast growing hemp (Cannabis sativa L.) for the production of boards for the building and furniture industry," BioRes. 12(2), 3521-3529.AbstractArticlePDF
    This paper describes an attempt to use long fibres from fast growing hemp (Cannabis sativa L.) as a raw material for the production of boards for the building and furniture industry. Hemp fibre boards with densities of 300 to 1100 kg/m3 were studied. The board surfaces were finished using a one-cycle method in which birch veneers were pressed to make the boards. The pulp was glued with pMDI (9 wt.% based on dry weight). The basic mechanical and hydrophobic properties of the boards were tested. The static bending strength and modulus of elasticity of the boards with a density of about 650 kg/m3 were comparable to P2 furniture boards. Only the higher density boards had adequate properties that met standards for the building industry, which were comparable to those of OSB/3 and MFP boards. Hemp fibre boards were characterised by relatively good water resistance, which was manifested by low swelling and low soaking susceptibility.
  • Researchpp 3530-3545Müller, T., Lenske, A., Hauptmann, M., and Majschak, J. P. (2017). "Analysis of dominant process parameters in deep-drawing of paperboard," BioRes. 12(2), 3530-3545.AbstractArticlePDF

    The application of the wrinkle measuring method described in Müller et al. (2017) and the subsequent evaluation algorithm of a range of deep-drawn samples were used to determine the influences and interdependencies of blankholder force, tool temperatures, and drawing height on the formation of wrinkles in paperboard. The main influences were identified and quantitatively evaluated. For the given experimental space, a regression function was derived and validated in further experiments. It was shown that a quadratic regression was superior to the previously used linear regression. The findings were discussed and compared with the results of similar experiments from past publications. Special attention was given to the wrinkles formed and the resulting quality of the formed paperboard cups. The restrictions of the data acquisition from the measuring method that was used and limitations of the model were presented to demonstrate the reliability of the results.

  • Researchpp 3546-3559Wu, X., Li, K., Song, F., and Zhu, X. (2017). "Fluidization behavior of biomass particles and its improvement in a cold visualized fluidized bed," BioRes. 12(2), 3546-3559.AbstractArticlePDF
    The fluidization behavior in a fluidized bed was visualized at room temperature under different conditions for two typical lignocellulosic biomass materials (rice husk and walnut shell) as representative samples of herbage and xylophyta, respectively. The effects of initial bed height, moisture content, and addition of sand particles on the quality of fluidization were analyzed, and the optimal operating parameters were determined. The initial bed height had a negligible effect on the minimum fluidization velocity but an obvious influence on bed stability. In addition, with an increase in moisture content, the minimum fluidization velocity showed the growth of an S-shaped curve and a constant decrease in the fluidization index in the fluidized region. Fluidization when performed on binary mixtures indicated that the proportion of sand-3 (60 to 80 mesh) in biomass and sand-3 in mixtures is a main factor contributing to the fluidizing quality of a bed. With larger proportions of sand-3, the fluidizing quality of the bed improved. Meanwhile, the differences in fluidization behavior between rice husk and walnut shell have been determined.
  • Researchpp 3560-3569Talagai, N., Borz, S. A., and Ignea, G. (2017). "Performance of brush cutters in felling operations of willow short rotation coppice," BioRes. 12(2), 3560-3569.AbstractArticlePDF

    Short rotation coppice is an option for timely procuring biomass for use as a source of energy, but it often requires the use of expensive equipment. Small-scale farmers lack the ability to purchase such equipment, but rather can use their own affordable tools. Performance of motor-manual harvesting using brush cutters in a short rotation willow coppice was evaluated by coupling traditional, Global Positioning System (GPS), and Geographic Information System (GIS) tools and methods. Strong dependence relations were found between the time effectively spent to fell willow shoots and the row length. The delay-free time consumption accounted for 81% of the total observed time, while the time spent to fell the shoots accounted for 97% of the delay-free time. The net production rate was low (0.13 ha h-1) being related to the technology used. Delays (19%) affected the performance resulting in a gross production rate of 0.11 ha h-1. Nevertheless, small-scale farmers use this level of technology in harvesting their crops by adapting the crop rotation to very short cycles, possibly to cope with technical limitations of brush cutters. The plantation system, layout, and the weather conditions may act as performance-limiting drivers. Also, adequate planning of the operational layout has the potential to increase the field performance.

  • Researchpp 3570-3582Björngrim, N., Fjellström, P. A., and Hagman, O. (2017). "Resistance measurements to find high moisture content inclusions adapted for large timber bridge cross-sections," BioRes. 12(2), 3570-3582.AbstractArticlePDF

    One challenge of monitoring and inspecting timber bridges is the difficulty of measuring the moisture content anywhere other than close to the surface. Damage or design mistakes leading to water penetration might not be detected in time, leading to costly repairs. By placing electrodes between the glulam beams, the moisture content through the bridge deck can be measured. Due to the logarithmic decrease of the resistance in wood as a function of electrode length, the model must be calibrated for measurement depth. Two models were created: one for electrode lengths of 50 mm and one for electrode lengths up to 1355 mm. The model for short electrodes differed by no more than 1 percentage points compared with the oven dry specimens. The model for long electrodes differed up to 2 percentage points for lengths up to 905 mm, and over that it could differ up to 4 percentage points.

  • Researchpp 3583-3600Ayrilmis, N., Hosseinihashemi, S. K., Karimi, M., Kargarfard, A., Kaymakci, A., and Ashtiani, H. S. (2017). "Technological properties of cement-bonded composite board produced with the main veins of oil palm (Elaeis guineensis) particles," BioRes. 12(2), 3583-3600.AbstractArticlePDF

    The effects of main veins of palm (Elaeis guineensis) particles and the amount of CaCl2 on the mechanical and physical properties of cement-bonded composite boards (CBCBs) were investigated in this study. Homogenous CBCBs were produced with main veins palm particles content at three levels of 10, 15, or 20 wt.% and CaCl2 at three levels of 0, 3, or 6 wt.%. Other manufacturing parameters consisting of pressure and time for cold-press, material dry weight, and panel dimensions were kept constant. The flexural strength, flexural modulus, internal bonding, water absorption, thickness swelling, and the thickness of CBCBs after 2 and 24 h immersion in distilled water were determined. The results indicated that increased amount of lignocellulosic particles caused a decrease in the mechanical properties of the CBCBs. The increase in calcium chloride up to 6 wt.% improved mechanical properties of the CBCBs. The panels manufactured with 10 wt.% E. guineensis particles and 6 wt.% CaCl2 showed the most favorable physical and mechanical properties.

  • Researchpp 3601-3617Tipu Sultan, M., Rahman, M. R., Hamdan, S., Lai, J. C. H., Talib, Z. A., and Md Yusof, F. A. B. (2017). "Impact of various pH levels on 4-methyl catechol treatment of wood," BioRes. 12(2), 3601-3617.AbstractArticlePDF
    Four types of treated wood (TW) were prepared by the impregnation of solid wood each with a solution of 4-methyl catechol at pH 8, a solution of 4-methyl catechol at pH 9, a solution of 4-methyl catechol at pH 10, and a solution of 4-methyl catechol at pH 11. These TW were characterized by Fourier transform infrared spectroscopic, X-ray diffraction (XRD), scanning electron microscopic, 3-point bending, free-free-vibration, and thermo-gravimetric analysis. FT-IR result showed that TW had more than one carbonyl absorbance band between 1745 and 1690 cm-1, while raw wood had only one carbonyl absorbance band in this regard. TW at pH levels of eight and nine showed higher crystallinity index (CIXRD) than that of raw wood. The SEM micrograph of TW at pH 8 had a smoother surface compared with other treated wood and raw wood. The modulus of elasticity (MOE), and modulus of rupture (MOR) of TW at pH 8 and pH 9 significantly increased. The raw wood exhibited a higher water uptake compared with the TW. The TGA results showed that TW were thermally less stable between 267 and 400 °C than raw wood.
  • Researchpp 3618-3629Jiménez, A. M., Delgado-Aguilar, M., Tarrés, Q., Quintana, G., Fullana-i-Palmer, P., Mutjè, P., and Espinach, F. X. (2017). "Sugarcane bagasse reinforced composites: Studies on the Young's modulus and macro and micro-mechanics," BioRes. 12(2), 3618-3629.AbstractArticlePDF

    The stiffness of a material greatly influences its possible use as an engineering material. Thus, despite the theoretical environmental advantages of natural fiber reinforced composites, or fully biodegradable composites, if certain mechanical properties are not achieved, a material can have fewer engineering uses. In this work, sugarcane bagasse fibers, a by-product of the sugarcane-juice extraction process, were used to obtain reinforcing fibers. Two polyolefins, a polypropylene and a high-density polyethylene, and a starch-based polymer were used as matrices. The composite materials were prepared and tested to obtain their tensile properties such as the Young’s moduli. Some micromechanical models were used to obtain the intrinsic Young’s moduli of the fibers and the efficiency factors. The dependence of such parameters on the matrix and fibers characteristics was studied. The fiber orientation efficiency factor was used to compute the orientation angle of the fibers inside the composite under three different distributions. Finally, the Tsai and Pagano models, and the Halpin and Tsai equations were used to compute the theoretical values of the Young’s moduli of the composites.

  • Researchpp 3630-3655Bernardini, J., Licursi, D., Anguillesi, I., Cinelli, P., Coltelli, M. B., Antonetti, C., Galletti, A. M. R., and Lazzeri, A. (2017). "Exploitation of Arundo donax L. hydrolysis residue for the green synthesis of flexible polyurethane foams," BioRes. 12(2), 3630-3655.AbstractArticlePDF

    Flexible polyurethane foams were prepared from solid waste residue derived from the hydrothermal acid treatment of the Arundo donax L. herbaceous biomass, which produced a very high yield of levulinic acid. An innovative, sustainable, and green liquefaction route was adopted to produce lignin-based flexible polyurethane foams by partially replacing fossil-fuel source polyols with an abundant and renewable hydroxyl source, the Arundo donax L. “lignin-like” residue. Lignin liquefaction was performed in polyolic solvents using microwave irradiation, saving time and energy while ensuring a more sustainable and green approach. Foam production was performed with controlled expansion using the “one-shot” technique. Water was adopted as the only blowing agent, and the isocyanate index (NCO/OH) was kept to less than 100, which reduced the cross-linking degree of the desired foam and increased its flexibility. About 7 wt.% of the conventional petrochemical polyether polyol was replaced with the Arundo donax L. hydrolysis residue. The chemical and mechanical properties of the synthesized foams were compared with those obtained by using a pure technical soda lignin, ProtoBind 1000. The results were characterized by satisfactory mechanical properties, thus closing the biorefinery cycle of Arundo donax L. exploitation.

  • Researchpp 3656-3665Wang, H., Huang, L., Cao, P., Ji, F., Yang, G., Guo, X., and Li, R. (2017). "Investigation of shear strength of engineered wood flooring bonded with PUR by response surface methodology," BioRes. 12(2), 3656-3665.AbstractArticlePDF
    The effects of process parameters (adhesive spreading rate, pressing time, and applied pressure) on the response parameter (shear strength) of engineered wood flooring bonded with polyurethane (PUR) were studied by response surface methodology. A mathematical model was established to provide a satisfying prediction for the experimental results observed. The model indicated a high degree of fitting. The results also showed that the major factors were adhesive spreading rate and pressing time. The optimized parameters for highest shear strength of engineered wood flooring were 98 g/m2 adhesive spreading rate with pressing time of 24 s and applied pressure of 1.2 MPa, respectively, within certain ranges.
  • Researchpp 3666-3676Lu, N., Yang, G., Chen, J., Wang, Q., Pei, L., and Lucia, L. A. (2017). "Producing hydrochar from cotton linter black liquor and performing alkali recovery," BioRes. 12(2), 3666-3676.AbstractArticlePDF

    Holistic utilization of cotton linter black liquor is crucial from both economic and environmental standpoints. For this purpose, the hydrothermal conversion process was selected to produce hydrochar from organic materials dissolved in black liquor. Fourier transform infrared spectroscopy (FT-IR) analysis showed that there were no significant functional changes in the hydrochar compared with black liquor solid (BLS) at different preserving temperatures. However, a C-O bond was ruptured by the hydrothermal carbonization. Thermogravimetric analysis also showed that the thermal stability of the hydrochar was increased. The higher heating value (HHV) of hydrochar at the different preserving temperature from 200 °C to 280 °C was higher than BLS, reaching a maximum at 200 °C. On the other hand, the alkali from the liquor production of hydrothermal carbonization was recovered by causticization; the highest causticizing efficiency (CE) was 45.2%. The recovered liquor alkali can be used in pulping or pretreatment strategies.

  • Researchpp 3677-3694Ma, M., Liu, R., Guo, Y., Li, H., Zhou, J., Wang, H., Lu, J., and Zhang, S. (2017). "Research on the dissolution of pentosans during Eucalyptus hydrolysate pretreatment," BioRes. 12(2), 3677-3694.AbstractArticlePDF

    Hydrolysate pretreatment (HP) uses hot water pre-hydrolysis liquor (HWPL) as partial or full pretreatment medium for biomass. Pentosan dissolution during Eucalyptus HP was studied under holding times between 0 min and 160 min, holding temperatures between 150 °C and 190 °C, a hot water pre-hydrolysate ratio (HWPR) from 20% to 100%, and a fixed liquid to wood ratio of 1:6. Both the pentosan removals in the hydrolysate pretreated solid (HPS) and the hydrolysate pretreatment liquor (HPL) pento-saccharides contents were determined and compared with those of hot water pre-hydrolysis (HWP). When compared to HWP, the HP enhanced pentosan removal from the solid phase, and enriched the saccharides or promoted the in-situ conversion of saccharides into other chemicals in the liquid phase. Pentosan removal in the HPS increased when holding time and temperature were increased. Increasing holding time first increased the pento-saccharide content in the HPL, and then decreased it after reaching the maximum. Elevating the holding temperature increased the pento-saccharide content in the HPL, except for arabino-oligosaccharide. Different HWPR had varying influences on pentosan removal in the HPS and on the saccharides concentration in the HPL. When controlled, HP positively influenced hemicellulose removal from biomass, and increased utilization value of the liquid phase obtained post pretreatment.

  • Researchpp 3695-3706Wu, Y., Yang, R., Lu, J., Li, H., Wang, H., and Zhou, J. (2017). "Hydrolysate-recycled liquid hot water pretreatment of reed straw and corn stover for bioethanol production with fed-batch, semi-simultaneous saccharification and fermentation," BioRes. 12(2), 3695-3706.AbstractArticlePDF

    Prehydrolysates and water-insoluble solids (WISs) were produced from reed straw and corn stover pretreated with hydrolysate-recycled liquid hot water (LHW) at different cycle times. The chemical components of the prehydrolysates and WISs were then investigated to assess the possible effects of hydrolysate recycling on bioethanol production. The WISs were subjected to fed-batch, semi-simultaneous saccharification and fermentation (S-SSF) to investigate the changes in bioethanol concentration and evaluate the efficiency of the pretreatment. The pretreatment conditions consisted of a temperature of 195 °C, time of 20 min, and liquid ratio of 1:20. The prehydrolysates were recycled using a circulation volume of 50% and were applied to 10 cycles. The results showed that recycling did not significantly decrease the pH of the hydrolysates. The content of glucose and xylan in the hydrolysates decreased and then increased with increasing cycle times. In the WISs, the contents of benzene alcohol extractives and ash increased remarkably. The content of acid-insoluble lignin and glucan increased slightly. The amounts of xylan and acid-soluble lignin in the WISs were low, and the changes in these contents were not significant. Thus, hydrolysate-recycled LHW pretreatment was beneficial for bioethanol production from reed straw, but not from corn stover.

  • Researchpp 3707-3719Yang, Z., Song, W., Cao, Y., Wang, C., Hu, X., Yang, Y., and Zhang, S. (2017). "The effect of laccase pretreatment conditions on the mechanical properties of binderless fiberboards with wheat straw," BioRes. 12(2), 3707-3719.AbstractArticlePDF

    Self-bonding technology is potentially an effective solution to overcome formaldehyde emissions, which pose health and environmental concerns. Laccases can activate the fiber surface during the binderless fiberboard manufacturing process. This paper adopted wheat straw fibers (WSF) as the main raw material. The purpose of this study was to examine the effects of laccase pretreatment conditions on the mechanical properties of binderless fiberboards produced from WSF. For the improvement of mechanical properties, bamboo fibers (BF) were added as a reinforcing material. In addition, differences in the effects of two processes for adding laccase on the mechanical properties were monitored. As a result, binderless fiberboards were successfully manufactured from laccase-treated WSF. The results showed that the optimized pretreatment conditions were determined to be a laccase dosage of 40 U per gram absolute dry fiber (U/g), a treatment time of 120 min, a treatment temperature of 50 °C, and a proportion of BF of 20%. The mechanical properties of the binderless fiberboards prepared using a water bath were superior to spraying under the same conditions.

  • Researchpp 3720-3727Sohi, A., Avramidis, S., and Mansfield, S. (2017). "Near-infrared spectroscopic separation of green chain sub-alpine fir lumber from a spruce-pine-fir mix," BioRes. 12(2), 3720-3727.AbstractArticlePDF
    The intention of this exploratory study was to determine whether near-infrared spectroscopy, combined with multivariate statistical modeling, could become a swift and accurate tool for identifying sub-alpine fir within a typical spruce-pine-fir (SPF) lumber mix in the green chain of a sawmill. This need arises from the difficulty encountered in the drying sub-alpine fir. Its identification and removal from the SPF mix before kiln drying may be quite beneficial for producing high quality lumber. Near-infrared spectra were obtained from scanning of small specimens that were prepared from freshly cut trees. The results of the initial principal component analysis indicated that all four components could be used for species differentiation with the help of partial least squares discriminant analysis. All specimens in the training set were fitted into the correct sub-group of either fir or spruce-pine groups. The test set was validated and it revealed that all specimens were correctly classified. The outcome also confirmed that near-infrared spectroscopy combined with multivariate statistical modeling could be a suitable prediction model for separation of sub-alpine fir from the SPF mix.
  • Researchpp 3728-3743Crespo, J., Aira, J. R., Vázquez, C., and Guaita, M. (2017). "Comparative analysis of the elastic constants measured via conventional, ultrasound, and 3-D digital image correlation methods in Eucalyptus globulus," BioRes. 12(2), 3728-3743.AbstractArticlePDF
    The design of engineering high value-added products and timber structures analysis requires reliable elastic characteristics related to a theoretical model that describes the elastic behavior of wood material. The present research focuses on determining the elastic constants of Eucalyptus globulus Labill., which allow their implementation as input parameters in any numerical model. The great potential of this species for novel structural applications was considered due to its superior mechanical properties. Two different testing methods were applied to the same specimens to directly compare the results. These two tests were conventional mechanical compression and a non-destructive ultrasound procedure. In addition, two different strain measurement techniques were contrasted in the performance of the mechanical tests, namely the conventional strain gauges that give local measurements, and the 3-D full-field optical system based on the principles of digital image correlation. The elastic values obtained via ultrasound are higher than those coming from mechanical testing using conventional gauges. Conventional gauges lead to underestimated values in comparison to the results from full-field strain measurements. Eucalyptus globulus shows greater longitudinal and transversal stiffness than the average values for other hardwoods, which verifies the good structural possibilities of this species.
  • Researchpp 3744-3750Wiwart, M., Bytner, M., Graban, L., Lajszner, W., and Suchowilska, E. (2017). "Spelt (Triticum spelta) and emmer (T. dicoccon) chaff used as a renewable source of energy," BioRes. 12(2), 3744-3750.AbstractArticlePDF
    The energy values of spelt (Triticum spelta) and emmer (T. dicoccon) chaff were determined and compared to wheat and barley straw. The thermophysical parameters (moisture content, lower calorific value, gross calorific value, content of fixed carbon, volatile matter, and ash) and elemental composition (content of C, H, S, N, and O) of spelt and emmer chaff were determined. Spelt and emmer chaff were characterized by higher gross calorific value (18.75 GJ/Mg vs. 18.31 GJ/Mg), higher lower calorific value (16.74 GJ/Mg vs. 16.35 GJ/Mg), noticeably lower ash content (3.79% vs. 6.16%) and lower content of volatile matter (70.3% vs. 74.9%) than wheat and barley straw. Emmer chaff contained noticeably more sulfur (0.148%), nitrogen (2.20%) and hydrogen (7.50%) than both types of straw (0.064%, 0.66% and 5.55% on average, respectively) and spelt chaff (0.071%, 0.80%, and 7.06%, respectively). Despite the fact that the relatively high sulfur content in emmer chaff is not desirable, the results of this study indicate that the chaff of hulled wheat had considerable energy potential and that hulled wheats could be effectively used as renewable sources of energy in the region of their production.
  • Researchpp 3751-3765Sanyang, M. I., Muniandy, Y., Sapuan, S. M., and Sahari, J. (2017). "Tea tree (Melaleuca alternifolia) fiber as novel reinforcement material for sugar palm biopolymer based composite films," BioRes. 12(2), 3751-3765.AbstractArticlePDF
    The tea tree (Melaleuca alternifolia) is well known for producing essential oil, which is used in medicinal and cosmetic products as a preservative, antiseptic, antibacterial, antifungal, and anti-pest additive. In this study, tea tree residues generated as agro-waste after the tea tree oil extraction process were utilized as cheap fiber material for the reinforcement of sugar palm starch (SPS)-based composite films. The crystallinity and functional groups of tea tree fiber (TTF) were investigated and the effect of TTF loading (0, 1, 3, 5, and 10 wt.%) on the tensile and morphological properties of TTF/SPS composite films were investigated. As the TTF loading increased from 0 to 10 wt.%, the tensile strength and modulus of TTF/SPS composite films were significantly increased, but their elongation at break declined. Optical microscopic and scanning electron microscopic images revealed that the TTF was randomly dispersed in all samples, and there was optimal compatibility between the fiber and matrix. Based on these findings, TTF can be considered as a potential reinforcement material for polymer composite films.
  • Researchpp 3766-3777Wu, H., Chen, F., Liu, M., and Wang, J. (2017). "Preparation of microcrystalline cellulose by liquefaction of Eucalyptus sawdust in ethylene glycol catalyzed by acidic ionic liquid," BioRes. 12(2), 3766-3777.AbstractArticlePDF

    Microcrystalline cellulose (MCC) was prepared from the residue of the incomplete liquefaction of eucalyptus sawdust; atmospheric liquefaction was carried out using ethylene glycol as the solvent and 1-(4-sulfobutyl)-3-methylimidazolium hydrosulfate as the catalyst. The highest cellulose content in the residue reached 93.9%. The MCC prepared from liquefaction was characterized by various techniques, which included infrared spectroscopy, X-ray diffraction, thermo-gravimetric analysis, and scanning electron microscopy. The results were compared to those of a commercial MCC (cotton linters). The analyses indicated that hemicelluloses and lignin were removed extensively from the MCC produced from the sawdust. The MCC was a cellulose I polymorph with 79.0% crystallinity. The particles were shaped as elongated rods and had good thermal stability. The particle sizes of the produced MCC ranged from 1 µm to 100 µm with a mean of 38.6 µm.

  • Researchpp 3778-3789Park, H. J., Wen, M. Y., Kang, C. W., and Sun, Y. X. (2017). "Development of physical pretreatment method for wood fire retardant impregnation," BioRes. 12(2), 3778-3789.AbstractArticlePDF

    To achieve a deeper and more uniform impregnation of water-soluble phosphorous-based fire retardants (WPFRs), in this work several physical pretreatment methods were developed including kerfing, boring, and the combination of both for structural square-wood posts in wooden buildings. Research was performed on three wood species, sugi (Cryptomeria japonica), larch (Larix olgensis), and Douglas fir (Pseudotsuga menziesii Franco), which are generally recognized as refractory wood species. The effects of pretreatment method on chemical uptake, chemical penetration, and mechanical properties were evaluated. The methods were compared with the incising method, a traditional method used for wood preservation. The results indicated that the pretreatments effectively increased the chemical uptake and penetration, especially in larch wood. Although the traditional incising method also increased the chemical uptake, it decreased the modulus of rupture (MOR) and compressive strength. The boring and combined method with a boring diameter less than 12 mm are recommended for WPFR wood impregnation.

  • Researchpp 3790-3800Wu, Z., Huang, D., Wang, W., Chen, T., Lin, M., Xie, Y., Niu, M., and Wang, X. (2017). "Optimization for fire performance of ultra-low density fiberboards using response surface methodology," BioRes. 12(2), 3790-3800.AbstractArticlePDF

    The optimization of the process conditions for fire retardant ultra-low density fiberboards (ULDFs) was investigated using response surface methodology (RSM). Three parameters, namely those of Borax-Zinc-Silicate-Aluminum (B-Zn-Si-Al), chlorinated paraffin (CP), and chloride-vinyl chloride emulsions (PVDC) were chosen as variables. The considerably high R2 value (99.98%) indicated the statistical significance of the model. The optimal process conditions for the limiting oxygen index (LOI) were determined by analyzing the response surface’s three-dimensional surface plot and contour plot, and by solving the regression model equation with Design Expert software. The Box-Behnken design (BBD) was used to optimize the process conditions, which showed that the most favorable dosages of B-Zn-Si-Al, CP, and PVDC were 800 mL, 46.47 mL, and 35.64 g, respectively. Under the optimized conditions, the maximum LOI was 48.4.

  • Researchpp 3801-3815Jiang, X., Zhao, T., Shi, Y., Wang, J., Li, J., and Yang, H. (2017). "H2SO4 and NaOH pretreatment to enhance bio-oil yield of pine wood liquefaction in methanol," BioRes. 12(2), 3801-3815.AbstractArticlePDF

    Pine wood was pretreated with H2SO4 and NaOH, followed by liquefaction in methanol at temperatures ranging from 200 to 350 °C, to produce bio-oil. Composition analysis and scanning electron microscopy (SEM) observation were performed to study the impact of the pretreatment on the pine wood structure. The SEM images showed that the structures of the samples were destroyed by pretreatment. After being pretreated by H2SO4, the size of holes generated was smaller than that with pretreatment by NaOH. Furthermore, the influences of the temperature, methanol content, and residence time on the yield of the water-soluble fraction (WS), ether-soluble fraction (ES), and bio-oil were determined. Shorter residence time and higher amounts of methanol favored the products of WS, ES, and bio-oil. Gas chromatography-mass spectrometry (GC-MS) analysis showed that phenols, ketones, aromatics, and aldehydes are the main components of bio-oil.

  • Researchpp 3816-3833Chowdhury, Z. Z., Pal, K., Johan, R. B., Yehya, W. A., Yehya Dabdawb, W. A., Ali, M. E., and Rafique, R. F. (2017). "Comparative evaluation of physiochemical properties of a solid fuel derived from Adansonia digitata trunk using torrefaction," BioRes. 12(2), 3816-3833.AbstractArticlePDF

    The effect of temperature on the physiochemical characteristics of a solid fuel or biocoal derived from the dried trunk of Adansonia digitata (Baobab) was studied using torrefaction processes. The chemical composition of the solid fuel or char obtained by wet (HTC) and dry torrefaction processes were determined by elemental and thermogravimetric (TGA) analyses. The Brunauer-Emmett-Teller (BET) surface area analyzer measured the porous texture and surface area of the prepared samples. The changes in the surface morphology and crystallinity of the prepared samples were evaluated by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The torrefaction process successfully improved the energy content from 16.8 MJ/kg to 22.0 MJ/kg, which was evidently higher than the starting precursors. The maximum energy yield obtained was 90.0% using dry torrefaction at 250 °C. The energy densification ratio was also higher for the char produced by the dry torrefaction process. However, the char produced by the HTC process at 250 °C showed the highest surface area. The pore diameter was higher for HTC-char produced at the same temperature. Overall the results revealed that the torrefaction of lignocellulosic biomass is beneficial for upgrading the fuel quality and energy densification of char residues.

  • Researchpp 3834-3849Jaber, S. M., Md Shah, U. K., Mohamed Asa’ari, A. Z., Ariff, A. B. (2017). "Optimization of laccase production by locally isolated Trichoderma muroiana IS1037 using rubber wood dust as substrate," BioRes. 12(2), 3834-3849.AbstractArticlePDF
    Laccases have great biotechnological potential in various industries as they catalyze the oxidation of a broad variety of chemical compounds, diamines, and aromatic amines. The production of laccases by fungi has been broadly studied due to their secretion of enzymes and their growth using cheap substrates. In this study, five native fungi isolates (Dr1, Dr2, Dr4, K5, and K9) were screened for laccase enzyme production. The ability to produce laccase was evaluated based on light green to dark color formation on a potato dextrose agar using 2,2’-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) as an indicator. The highest laccase production was obtained by Dr4, which was identified as Trichoderma muroiana IS1037. Among the different carbon sources tested (rubber wood dust, rice straw, sugar cane bagasse, and oil palm empty fruit bunch), the highest laccase activity (5.84 U/mL) was obtained in submerged fermentation using rubber wood dust as substrate. Laccase production was further enhanced with the addition of 2 mM copper sulfate. In conclusion, the local fungus isolate Trichoderma muroiana IS1037 is a potential fungi-producing laccase that can use rubberwood dust as carbon source.
  • Researchpp 3850-3863He, X., Xiong, X., Xie, J., Li, Y., Wei, Y., Quan, P., Mou, Q., and Li, X. (2017). "Effect of microwave pretreatment on permeability and drying properties of wood," BioRes. 12(2), 3850-3863.AbstractArticlePDF

    A microwave (MW) treatment of plantation eucalyptus (Eucalyptus urophylla) wood was investigated by applying MW treatments with varying conditions, such as radiation power, irradiation time, and initial moisture content of the wood. The wood permeability and drying properties were investigated. Results show that the permeability (both along the transverse and longitudinal directions) increased with the radiation power and the irradiation time. The permeability was considerably enhanced by the MW pretreatments, which effectively decreased the moisture content within the wood. A MW pretreatment can greatly accelerate the drying rate and shorten the wood drying time. Under atmospheric pressure the stain uptake along the transverse and longitudinal directions, with respect to the wood fibers, increased to 58% and 135%, respectively, compared to reference samples. Meanwhile, the drying rate increased to 171% and the drying time was cut by 65%. The MW pretreatment was found to generate a high-pressure internal steam that resulted in the rupture of wood cell pore membranes and ray cells. Therefore, a remarkable permeability increase and drying time reduction was achieved, which created favorable conditions for the fabrication of high value-added functional wood-based composites materials.

  • Researchpp 3864-3875Zhang, C., Lei, L., Li, Y., and Chen, J. (2017). "Integrated ozonation and biotreatment of bio-treated pulping wastewater," BioRes. 12(2), 3864-3875.AbstractArticlePDF

    Bio-treated pulping wastewater (BTPW) was further treated using a combination of ozonation and biotreatment processes. The effect of ozonation on chemical oxygen demand (CODCr) removal and biodegradability enhancement of the BTPW was investigated. The results showed that the ozonation was effective for degrading the pollutants in the BTPW and improving its biodegradability. The CODCr removal reached approximately 34.8%, and the BOD/COD ratio increased from less than 0.15 to 0.36, after ozonation for 30 min. The raw BTPW biodegrades poorly, and treatment using a combination of ozonation with biotreatment could eliminate most of the refractory substances from the BTPW. The CODCr removal rates of the BTPW were 55.4% and 64.3% for the treatments using ozonation for 30 or 60 min, respectively, before subsequent biotreatment for 14 days. The CODCr removal rates were higher than that of the biological treatment alone by 44.7% and 53.6%, respectively.

  • Researchpp 3876-3889Ayata, U., Gurleyen, L., Esteves, B., Gurleyen, T., and Cakicier, N. (2017). "Effect of heat treatment (ThermoWood) on some surface properties of parquet beech (Fagus orientalis Lipsky.) with different layers of UV system applied," BioRes. 12(2), 3876-3889.AbstractArticlePDF
    Heat treatment is known to improve the stability and durability of various woods. However, in the process some surface properties are changed. This paper reports the changes in surface properties such as color, glossiness, pendulum hardness, and surface adhesion on coated heat-treated and untreated beech wood. The wood was coated with an epoxy acrylic resin sealer followed by a polyacrylic-based resin varnish that is normally applied on parquet with single and double layers according to the manufacturer’s recommendations. The results showed that in relation to color parameters, the lightness decreased while a* increased in response to heat treatment. This was followed by a decrease in the redness (a*) and a decrease in yellow (b*) with the intensity of the treatment. There was an initial increase in the glossiness but it decreased later on with the severity of the treatment. The hardness and adhesion also decreased with the severity of the treatment for beech coated with single and double layers. The wood surface properties depended on the treating time and the temperature of the treatment.
  • Researchpp 3890-3904Rashidi Jouybari, I., Yoosefi, M., and Azadfallah, M. (2017). "Preparation of cationic CMP and softwood long fibers as strength-enhancing additive to CMP pulp," BioRes. 12(2), 3890-3904.AbstractArticlePDF
    Compared to chemical pulp, mechanical and chemi-mechanical pulps (CMP) are limited in regards to the manufacturing of high quality paper. Chemical additives are an effective way to enhance the properties of paper; however, the effectiveness depends on the additive type and dosage. The utilization of cationized natural polymers has been shown to offer a promising solution. In this study, softwood long fiber (SLF) and CMP were cationized by 3-chloro-2-hydroxypropyl-trimethylammonium-chloride (CHPTAC), and the effects of cationization on the properties of CMP pulp were studied. Cationization was characterized by FTIR and the nitrogen content, and its effect on the CMP properties was evaluated through mechanical tests and fines retention. Cationization at low and moderate levels and in higher mixing rates improved the mechanical properties of CMP. Compared to cationized CMP, the addition of cationized SLF (CLF) improved the strength and fines retention properties. The CLF application to CMP at a CHPTAC dosage of 5% increased the tensile, burst, and tear strengths by 66.4%, 100%, and 3.6%, respectively. The cationized SLF increased the fines retention by 12.7%.
  • Researchpp 3905-3917Chi, C., Hui, Z., Liu, M., Zhang, S., and Gong, Y. (2017). "Effect of acetic acid pretreatment on wood pore structure and fractal dimension," BioRes. 12(2), 3905-3917.AbstractArticlePDF

    The acetic acid pretreatment of wood chips has become one of the most promising technologies for biorefinery. This study aimed to provide a quantitative evaluation of the porosity variation during pretreatment based on the fractal dimension methodology. The acacia wood sample was pretreated by acetic acid under different temperatures (140 °C to 170 °C), followed by a three-stage disc-refining at high consistency, and was subsequently characterized by the low-temperature nitrogen adsorption method. The detailed data related to the fractal dimension were obtained by two well-established methods, namely, the Yu Boming (YBM) fractal and Frenkel Halsey Hill (FHH) fractal method. Both the acetic acid pretreatment and disc refining resulted in a higher fractal dimension, which indicated increased irregularity of the pore structure. The mechanism behind the temperature’s effect, where the higher temperature led to a lower fractal dimension, was also explored. Compared to the FHH dimension, the fitting range of the YBM dimension was wider and it had a lower correlation coefficient.

  • Researchpp 3918-3932Fan, F., Zheng, Y., Huang, Y., Lu, Y., Wang, Z., Chen, B., and Zheng, Z. (2017). "Combustion kinetics of biochar prepared by pyrolysis of macadamia shells," BioRes. 12(2), 3918-3932.AbstractArticlePDF

    The use of macadamia shells (MSs) has become an active research direction because of increasing production. This paper considers the combustion characteristics of MSs and their biochars that were investigated with thermogravimetry analysis (TGA). Combustion thermographs were obtained at different heating rates, using isoconversional methods expressed by combustion kinetics. The Kissinger-Akahira-Sunose (KAS) method authenticated the MSs, MSs-300, and MSs-600 average activation energy at 91.6 kJ/mol, 60.5 kJ/mol, and 50.1 kJ/mol, respectively. The Flynn-Wall-Ozawa (FWO) method authenticated these at 97.1 kJ/mol, 68.7 kJ/mol, and 59.5, kJ/mol. The Coats-Redfern method verified the samples combustion via a complex multi-step mechanism; the first stage mechanism had different activation energies at different heating rates. With increased heating rates, the activation energies of biochar decreased, and the activation energies of MSs for the second combustion zone also decreased. At the same heating rate, MSs-600 had higher activation energy values than MSs-300. The TGA curves and kinetic parameters demonstrated the superiority of the biochar derived MSs as a fuel substrate over its precursor.

  • Researchpp 3933-3947Liu, H. M., Li, H. Y., Wei, A. C. (2017). "Enhanced polysaccharides yield obtained from hydrothermal treatment of corn bran via twin-screw extrusion," BioRes. 12(2), 3933-3947.AbstractArticlePDF

    Lignocellulosic biomass, such as corn bran, has limited accessibility to solvents during thermal-chemical processes. However, a pretreatment can help to change the characteristics of the raw material and improve the yield of the polysaccharides. A twin-screw extrusion pretreatment was developed to enhance the polysaccharide yield and decrease the optimum temperature and time during the hydrothermal treatment of corn bran. The effects of temperature and time on the polysaccharide yield were investigated during the hydrothermal treatment with pretreated and unpretreated corn bran. All samples were comparatively analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis to investigate the changes in the chemical and physical characteristics. The results showed that the twin-screw extrusion pretreatment changed the main physical structure and thermochemical behavior of corn bran, which confirmed that it could enhance the polysaccharide yield and decrease the optimum treatment temperature and reduce the process duration. The pretreatment and the hydrothermal treatment temperature also had a synergetic effect on extraction yield and the composition of polysaccharide fractions of corn bran compared to the unpretreated sample. This study contributes to the knowledge improvement of corn bran pretreatments, which can be used for the efficient production of polysaccharides.

  • Researchpp 3948-3964Chen, F., Li, Q., Gao, X., Han, G., and Cheng, W. (2017). "Impulse-cyclone drying treatment of poplar wood fibers and its effect on composite material's properties," BioRes. 12(2), 3948-3964.AbstractArticlePDF

    The fiber quality after a conventional drying treatment used for wood-plastic composites (WPCs) cannot be ascertained prior to use. Through the application of scanning electron microscopy, Fourier transform infra-red spectroscopy, and X-ray diffraction, the effect of an impulse-cyclone drying (ICD) treatment on the quality of poplar wood fiber was first investigated. Subsequently, the effect of ICD conditions, such as inlet temperature, inlet wind velocity, and feed rate on the mechanical properties of WPCs and fiber dispersibility was considered. Also, the quality of fibers and WPCs was compared to those treated via an oven-drying method. Poplar wood fibers with a moisture content of 12.4% were pre-treated at different drying conditions by ICD. The obtained fibers were compounded with high-density polypropylene. The results showed that ICD could promote the hydration of poplar wood fibers and improve the mechanical properties of WPCs. The ICD-treated wood fibers were uniformly dispersed in the plastic matrix. With the increase of inlet temperature, the number of hydroxyl and carbonyl groups of poplar fibers decreased, whereas the degree of crystallinity increased as the in-let temperature and fiber meshes was increased. This study demonstrated the feasibility for the application of an ICD treatment in the WPCs production industry.

  • Researchpp 3965-3975Zhou, D., Guo, X., Yan, S., and Di, M. (2017). "Combined surface treatment of wood plastic composites to improve adhesion," BioRes. 12(2), 3965-3975.AbstractArticlePDF

    To improve the adhesion properties, the surfaces of polyethylene wood plastic composites (WPCs) were treated by a combination of sanding then coating with a silane coupling agent, followed by plasma discharge. The surface properties of polyethylene WPCs were studied by assessing the contact angle and bonding strength, as well as implementing Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The results indicated that the roughness of the composites increased during the combined treatment, when compared with the untreated composites. The content of the oxygen elements on the surfaces of the combined treated composites also was found to increase. This indicated that there were polar groups formed, such as –OH, –C=O, and –O–C=O. The surface wettability of the composites improved after the combined treatment. At the same time, chemical bonding between the coupling agent and the wood fibers of the sanding-treated composites occurred. The surface properties of the polyethylene WPCs were changed by the combined treatment, which became favorable for adhesiveness. After the combined treatment, the shear strength and durability of the bonding joints of the composite increased significantly and displayed a synergistic effect from the surface treatment.

  • Researchpp 3976-3991Abdalhadi, D. M., Abbas, Z., Ahmad, A. F., and Ibrahim, N. A. (2017). "Determining the complex permittivity of oil palm empty fruit bunch fibre material by open-ended coaxial probe technique for microwave applications," BioRes. 12(2), 3976-3991.AbstractArticlePDF

    A material description was established for oil palm empty fruit bunch (OPEFB) fibre waste for microwave absorber applications by determining its dielectric properties with respect to fibre size and frequency. The proposed OPEFB material was studied at frequencies from 1 to 4 GHz. The study was conducted using the open-ended coaxial probe (OECP) HP85071C technique. The effect of microwave frequency on complex permittivity properties for powdered OPEFB and compressed OPEFB with different particle sizes (100, 200, 300, 400, and 500 μm) were investigated. Results showed that the microwave frequency and particle size significantly influenced the complex permittivity (real and imaginary) properties of the samples. Moreover, the complex permittivity decreased as the powder fibre size increased. The complex permittivity of the smallest and largest powder fibre sizes (100 and 500 μm) were (2.050 − j 0.197) and (1.934 − j 0.137), respectively; and the complex permittivity of the smallest and largest compressed OPEFB fibre sizes (100 and 500 μm) were (3.799 − j0.603) and (3.326 − j0.486), respectively. The compressed OPEFB complex permittivity was higher than that of the OPEFB powder.

  • Researchpp 3992-4003Jelonek, T., Pazdrowski, W., Tomczak, A., and Arasimowicz-Jelonek, M. (2017). "Lignification markers of the tracheid walls of Scots pine (Pinus sylvestris (L.)) in various forms of dead bark," BioRes. 12(2), 3992-4003.AbstractArticlePDF
    This study attempted to define the shaping of the quotient of fresh-needled twig mass and fresh conifer needle mass to the lignin content (MFT/LC) in the tracheid walls of the circumferential zone of trunks (MFN/LC) of pines with various forms of dead bark, which were called lignification markers. In the experiment, the researched trees had varying forms of dead bark, including ropy bark (G), scaly bark (L), and shell-type bark (M). The research material came from pine timber forests aged between 89 years to 91 years, located in Northern Poland. A tree tissue chemical analysis encompassed a zone of mature sapwood, i.e., the last ten annual growth rings of diameter increment located at the height of 1.30 m (diameter at breast height-DBH). The acquired results pointed to the fact that pines with dead bark in the ropy form possessed statistically higher values of the analyzed markers (MFT/LC and MFN/LC) than the trees with scaly and shell-type bark. The variances ascertained in the course of the experiments of both markers in the Scots pine (Pinus sylvestris (L.)) are possibly connected to the physiological, physical, and structural conditioning of water transportation, with mineral salts in the stem of the trees.
  • Researchpp 4004-4012Büyüksarı, Ü., As, N., and Dündar, T. (2017). "Mechanical properties of earlywood and latewood sections of Scots pine wood," BioRes. 12(2), 4004-4012.AbstractArticlePDF
    The aim of this study was to determine the mechanical properties of earlywood (EW) and latewood (LW) sections of Scots pine (Pinus sylvestris L.) wood, and determine the relationship between calculated and measured values. The bending strength, modulus of elasticity in bending, and the tensile strength of EW and LW sections were determined. The mechanical properties were calculated using EW and LW mechanical properties and LW proportion. Also, mechanical properties were determined in standard size samples and compared to the calculated properties. In earlywood and latewood sections, the bending strength was 37.3 MPa and 93.9 MPa, the modulus of elasticity in bending was 1557.6 MPa and 3600.4 MPa, and the tensile strength was 58.6 MPa and 189.6 MPa, respectively. The results showed that the LW section had higher mechanical properties than those of the EW section for all of the measured mechanical properties. The calculated bending strength, modulus of elasticity, and tensile strength values were 53.3 MPa, 2133.7 MPa, and 95.5 MPa, respectively. The calculated bending strength and modulus of elasticity values were lower compared to the measured values, while the calculated tensile strength values were higher than that of the measured values.
  • Researchpp 4013-4030Bernal, O. I., Pawlak, J. J., and Flickinger, M. C. (2017). "Microbial paper: Cellulose fiber-based photo-absorber producing hydrogen gas from acetate using dry-stabilized Rhodopseudomonas palustris," BioRes. 12(2), 4013-4030.AbstractArticlePDF
    The microstructure and reactivity of a novel nonwoven cellulose fiber cellular biocomposite (microbial paper) was studied relative to long-term stabilization of potentially any microorganism. Cells were incorporated during the papermaking process as an integral component of a highly porous cellular biocomposite that can be dry stabilized. Hydrogen gas production from acetate via the activity of the nitrogenases in Rhodopseudomonas palustris CGA009, entrapped at a very high concentration, in hand-made microbial paper was sustained for > 1000 h at a rate of 4.0 ± 0.28 mmol H2/m2 h-1 following rehydration. This rate is 2x and 10x greater than previously reported H2 production rates by Rps. palustris latex coatings that were dried on polyester and non-dried formulations applied to the surface of paper, respectively. By vacuum-dewatering and controlled drying steps to the microbial papermaking process and incorporating blends of microfibrillar (MFC), softwood (SW), and hardwood (HW) cellulose fibers, microbial paper films were fabricated that produced H2 gas at 3.94 ± 1.07 mmol H2/m2 h-1 and retain up to 60 mg/m-2 dry cell weight (DCW) of Rps. palustris. The MFC content appears to determine the final cell load and may affect gas/moisture mass transfer properties of the biocomposite.
  • Researchpp 4031-4048Kuparinen, K., and Vakkilainen, E. (2017). "Green pulp mill: Renewable alternatives to fossil fuels in lime kiln operations," BioRes. 12(2), 4031-4048.AbstractArticlePDF

    Pulp mills are making increasing efforts to reduce fossil fuel use and carbon dioxide emissions. Lime kilns, which are typically fired with fuel oil or natural gas, use the most fossil fuel in modern pulp mills. A modern kraft pulp mill can be fossil fuel-free during normal operation if fossil-based lime kiln fuels are substituted with renewable alternatives. This study compared the production and use of various renewable fuels, namely, hydrogen, producer gas, torrefied biomass, lignin, and pulverized biomass, in lime kiln operations in a 1.5 Mt/a kraft pulp mill in South America to define the techno-economic optimum for the fossil fuel-free operation of the pulp mill. The attractiveness of each of the concepts was dependent on local conditions and especially the prices of fossil fuels and electricity. The results showed, however, that feasible options exist for the replacement of fossil fuels in lime kiln operations.

  • Researchpp 4049-4061Liang, C., Hu, Y., Guo, L., Wu, L., and Zhang, W. (2017). "Kinetic study of acid hydrolysis of corncobs to levulinic acid," BioRes. 12(2), 4049-4061.AbstractArticlePDF

    Levulinic acid (LA) is an important platform compound that can be obtained from biomass resources. Using corncobs as the raw material that had already removed the hemicellulose, this work studied the relevant hydrolysis kinetics. The kinetic experiments were performed at various temperatures in the range of 150 °C to 180 °C and sulfuric acid concentrations between 0.2 mol/L and 0.8 mol/L in a reactor designed by the authors. The highest yield of LA was obtained at 150 °C and 0.8 mol/L H2SO4 at 58.0 mol%. A new simple kinetic model that consists of four first-order reactions was proposed; the model assumes that humins can be only converted from 5-hydroxymethylfurfural (5-HMF). A modified parameter fitting method that contained equality constraints and a weighted objective function was applied in this study. The kinetic model was in excellent agreement with the experimental data.

  • Researchpp 4062-4077Wang, H., Zhang, X., Wei, Y., Zhang, A., Liu, C., and Sun, R. (2017). "Homogeneous esterification mechanism of bagasse modified with phthalic anhydride in ionic liquid, Part 3: Structural transformation of lignins," BioRes. 12(2), 4062-4077.AbstractArticlePDF

    The phthalation of bagasse was investigated comparatively with the three main isolated components in 1-allyl-3-methylidazium chloride (AmimCl) to reveal the reaction behavior of bagasse. In the first two parts, the detailed changes of cellulosic and hemicellulosic components in bagasse were elucidated during phthalation. In Part 3, the phthalation of lignins was performed in AmimCl with various ratios of phthalic anhydride/lignins from 10 to 50 mmol/g. The phthalation degree ranged from 41.1% to 68.8% for the phthalated lignins. The aliphatic hydroxyls of lignins were more easily phthalated than the phenolic hydroxyls as revealed by 31P nuclear magnetic resonance (NMR) analysis. Fourier transform infrared spectroscopy (FT-IR) and two dimensional (2D) heteronuclear single quantum correlation (HSQC) confirmed the attachment of phthaloyl group onto lignins. Severe degradation of lignin macromolecules was found at high ratios of phthalic anhydride/lignins (30 to 50 mmol/g) by gel permeation chromatography (GPC) analysis. These results provide a detailed understanding of reaction behaviors of lignins during bagasse phthalation, which are beneficial to prepare composites based on phthalated lignocellulose with better properties.

  • Researchpp 4078-4092Nasser, R. A., Mansour, M. M. A., Salem, M. Z. M., Ali, H. M., and Aref, I. M. (2017). "Mold invasion on the surface of wood/polypropylene composites produced from aqueous pretreated wood particles, Part 1: Date palm midrib," BioRes. 12(2), 4078-4092.AbstractArticlePDF

    The effect of particle pretreatments on the biodeterioration of wood-plastic composites (WPCs) was investigated. WPCs made from untreated and pretreated frond midrib particles of date palm were used. Before the addition of a coupling agent, the wood particles were pretreated or extracted with either cold or hot water and mixed with polypropylene to produce panels, which were then superficially inoculated with an ascomycete’s fungus Trichoderma harzianum T6776. The WPC surfaces were studied using scanning electron microscopy (SEM) and electron dispersive X-ray spectroscopy (EDX) measurements. In comparison with the control, an intensive growth of T. harzianum hyphae was found over the WPC surface manufactured from untreated date palm midrib particles with the colonies clearly visible. The pretreatments of date palm particles reduced the growth of T. harzianum in comparison with the control and untreated particles. The results suggested that particle pretreatments could be a suitable way to limit the growth of molds over WPC surfaces made from date palm midrib.

  • Researchpp 4093-4110Amini, E., Tajvidi, M., Gardner, D. J., and Bousfield, D. W. (2017). "Utilization of cellulose nanofibrils as a binder for particleboard manufacture," BioRes. 12(2), 4093-4110.AbstractArticlePDF

    Cellulose nanofibrils (CNF) were investigated as a binder in the formulation of particleboard (PB) panels. The panels were produced in four different groups of target densities with varying amounts of CNF binder. The produced panels were then tested to determine the modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), water absorption (WA), and thickness swelling (TS) properties. Density gradients through the thickness of the panels were evaluated using an X-ray density profiler. The effect of drying on the strength development and adhesion between CNF and wood particles (WP) was investigated, and the effect of surface roughness on the wood-CNF bonding strength was evaluated through lap shear testing and scanning electron microscopy. It was found that at lower panel densities, the produced samples met the minimum standard values recommended for particleboard panels. Medium-density panels met the standard levels for IB, but they did not reach the recommended values for MOR and MOE. The possible bonding mechanism and panel formation process are discussed in light of microscopic observations and the results of lap shear tests were presented.

  • Researchpp 4111-4122Ooi, Z. X., Chan, K. L., Ewe, C. Y., Muniyadi, M., Teoh, Y. P., and Ismail, H. (2017). "Evaluation of water affinity and soil burial degradation of thermoplastic film derived from oil palm ash-filled polyvinyl alcohol," BioRes. 12(2), 4111-4122.AbstractArticlePDF
    Oil palm ash (OPA) produced through the incineration process were used as a blending material with polyvinyl alcohol (PVOH) to produce a thermoplastic film. Prior to blending, the oil palm ash was characterized using a scanning electron microscope (SEM), Fourier transform infrared spectroscopy, and x-ray diffraction (XRD). The OPA was successfully blended with polyvinyl alcohol to produce plastic films at various ratios of oil palm ash. The properties of these blended polyvinyl alcohol/oil palm ash films were then characterized using SEM, water absorption, and soil burial tests. The water absorption decreased as the content of the oil palm ash increased. Blended polyvinyl alcohol/oil palm ash films showed a better degradation when the concentration of oil palm ash was increased.
  • Researchpp 4123-4145Nnaji, C. C., and Emefu, S. C. (2017). "Effect of particle size on the sorption of lead from water by different species of sawdust: Equilibrium and kinetic study," BioRes. 12(2), 4123-4145.AbstractArticlePDF
    Both the effect of particle size and initial concentration on the adsorption of lead by sawdust of two timber species were investigated using batch experimental equilibrium and kinetic studies. A 100% lead removal efficiency was recorded for the optimum particle size of 1.18 mm for Pycnanthus angolensis and 0.85 mm for Khaya ivorensis at an initial lead concentration of 10 mg/L. Freundlich isotherm (0.83 ≤ R2 ≤ 0.96 for Khaya ivorensis and 0.94 ≤ R2 ≤ 1.0 for Pycnanthus angolensis) performed better than Langmuir and Temkin isotherms. The Dubinin-Radushkevich isotherm was used to ascertain the sorption mechanism. Mean sorption energy (12.48 kJ/mol for Pycnanthus angolensis and 13.42 kJ/mol for Khaya ivorensis) indicated that adsorption was by ion exchange. The pseudo-first order kinetic model (0.96 ≤ R2 ≤ 1.0 for Khaya ivorensis and 0.90 ≤ R2 ≤ 1.0 Pycnanthus angolensis) performed better than others with respect to R2 values, while the intraparticle diffusion model performed better than the other kinetic models with respect to absolute mean error (AME).
  • Researchpp 4146-4165Svoboda, T., Gaffová, Z., Rajnoha, R., Šatanová, A., and Kminiak, R. (2017). "Bending forces at the proportionality limit and the maximum - technological innovations for better performance in wood processing companies," BioRes. 12(2), 4146-4165.AbstractArticlePDF

    Knowledge of the force required to overcome deformation at the proportionality limit, maximum limit, and their ratio, as well as knowledge of the effect of selected factors on the listed characteristics in bending stress, have both scientific and practical significance. They form a foundation for designing tools for bending and determine the stress that products and their parts can be exposed to during use. This study analyzes the effect of selected factors on the force at the proportionality limit (FE), the force at the maximum limit (FP), and the ratio of these two characteristics (FE/FP). This study examined the effect of the wood species (WS) (Fagus sylvatica L. and Populus tremula L.), material thickness (MT) (4 mm, 6 mm, 10 mm, and 18 mm), degree of densification (DOD) (0%, 10%, and 20%), and the number of cycles (NOC) (0 or 10,000), as well as their combined interaction, on the monitored characteristics. The results contribute to the advancement of knowledge necessary for the study and development of new materials with specific properties for their intended use. The results can improve the innovative potential of wood processing companies and increase their performance and competitiveness in the market.

  • Researchpp 4166-4176Saeed, H. A. M., Liu, Y., Lucian, L. A., and Chen, H. (2017). "Sudanese agro-residue as a novel furnish for pulp and paper manufacturing," BioRes. 12(2), 4166-4176.AbstractArticlePDF

    Sudan has rich sources of lignocellulose materials from agricultural waste that have potential to be used as a papermaking furnish following adequate chemical compositions, elemental analysis, fibre dimensions, and morphology of millet stalks and date palm leaves. Paper sheet properties from the various pulps made were investigated, and it was found that there was no difference in the polysaccharide (cellulose and hemicelluloses) content between millet stalks and date palm leaves, although millet stalks had a high lignin content of 18.20% relative to date palm leaves’ content of 15.34%. Moreover, millet stalks showed a high pulp yield (42.04%) with a viscosity of 665 mL/g compared to that (34.43%, 551 mL/g) and (38.50% and 534 mL/g) of date palm leaves and the blend, respectively. Papers produced from date palm leaves and millet stalk blends showed better physical properties compared to that of pure millet stalks and date palm leaves. The Scanning Electron Microscopy (SEM) analysis showed that fibres in the blend were more closely packed than that of the pure millet stalks and date palm leaves fibers. Based on their physical and chemical composition properties, millet stalks and date palm leaves have a high potential as a furnish for pulp and papermaking.

  • Researchpp 4177-4186Vidholdová, Z., Reinprecht, L., Igaz, R. (2017). "The impact of laser surface modification of beech wood on its color and occurence of molds," BioRes. 12(2), 4177-4186.AbstractArticlePDF

    Molds in wet and warm environments often attack surfaces of products made from beech and other less or moderately durable woods. This paper presents the effects of the physical modification of beech wood with a CO2 laser having a constant power output of 45 W, using eight radiation doses from 7.8 to 75 J/cm2. Variations in laser activations created a scale of color changes in surfaces of beech wood determined in the CIE L*a*b* system, ranging from an apparently unaffected to totally dark due to carbonization effects. The surfaces of beech samples modified by laser were subsequently infected with the molds Aspergillus niger and Penicillium brevicompactum, and their growth on the top surfaces of beech samples was evaluated according to the standard STN 49 0604 (1980). The modified surfaces of beech wood exposed to higher CO2 laser powerful effects (i.e., radiation doses 25 J/cm2 and more) obtained evidently higher resistance to Aspergillus niger, but their resistance to Penicillium brevicompactum changed only minimally.

  • Researchpp 4187-4201Mansour, M. M. A., Nasser, R. A., Salem, M. Z. M., Ali, H. M., and Hatamleh, A. A. (2017). "Study of mold invasion on the surface of wood/polypropylene composites produced from aqueous pretreated wood particles, Part 2: Juniperus procera wood branch," BioRes. 12(2), 4187-4201.AbstractArticlePDF

    Mold invasion by Trichoderma harzianum T6776 over the surface of wood-plastic composites (WPCs) made from Juniperus procera wood-branch and polypropylene with a melt-blending technique was examined using scanning electron microscopy (SEM) and electron dispersive X-ray spectroscopy (EDX). Before the addition of coupling agent, the WPC samples were made from untreated and pretreated wood-branch particles of J. procera with either cold or hot water and then mixed with polypropylene to produce panels. The surfaces of WPC samples were inoculated by a mold suspension of T. harzianum. SEM-EDX measurements of WPCs made from J. procera particles showed little or no growth of T. harzianum, irrespective of treatment with cold or hot water. The results suggest that WPCs made from the particles of J. procera wood-branch pretreated with either cold or hot water could be useable in wet conditions. In addition, using of J. procera as durable wood for manufacturing of WPCs had good effects on the prevention of the mold infestation over the surfaces of the produced panels.

  • Researchpp 4202-4213Podlena, M., Böhm, M., Múčka, M., and Bomba, J. (2017). "Determination of the bending moment of a dowel and tenon joint on window profile IV 92 of a wooden window," BioRes. 12(2), 4202-4213.AbstractArticlePDF

    This study deals with calculating and comparing the bending moments of two types of corner joints for commercially produced wooden sashes. The triple tenon and mortise joint was compared to a dowel joint on the sash of a window profile IV 92, made of spruce glued laminated timber. On the testing machine, the maximum force in the angular plane of a window sash under compression or tension mode was applied, and the measured values were converted to the bending moments. A significant difference between the bending moments for the mortise and tenon joint, and dowel joint were determined. The dowel joints achieved 167 Nm in a tensile test and 168 Nm in a compression test, while the mortise and tenon joint achieved 344 Nm in a tensile test and 325 Nm in a compression test. However, a significant difference was not revealed between the compression and tension tests for both types of joints. The differences for both types of joints were explained via the different sizes of the bonded surfaces, which was higher for the tested triple tenon and mortise joint by 29%.

  • Researchpp 4214-4228Zeng, L., Zeng, B., Chen, J., Zhang, L., Zhan, P., Hu, B., and Zhang, Y. (2017). "Synergistic fermentation of camphor leaves by cellulolytic fungus and optimization of reducing sugar production," BioRes. 12(2), 4214-4228.AbstractArticlePDF

    The degradation of lignocellulosic materials requires the synergy of multiple enzymes. Synergistic fermentation would be an alternative to a complete enzyme system and consequentially enhance enzymatic production. The present study used cellulolytic fungus of Penicillium decumbens, Aspergillus niger C112, and Trichoderma reesei RutC-30 as the starting strains, to screen for the best combination and proportion of synergistic fermentation. The experiments of different combinations and inoculum ratios for synergistic fermentation were performed, and Box-Behnken designs were adopted to optimize the fermentation conditions. The best combination of strains was confirmed as T. reesei RutC-30 and P. decumbens with an 8:2 inoculum ratio. The maximum sugar concentration was 1.48 g/L with CMCase (17.53 U/mL) and FPase (4.78 U/mL) in this situation. Response surface methodology revealed the optimized parameters as a substrate concentration of 5.93% at 32.12 °C, and a fermentation time of 5.85 d with a predicted sugar concentration of 2.91 g/L. Under these conditions, a maximum sugar production of 2.96 g/L was achieved in verification experiments.

  • Researchpp 4229-4238Kang, H. Y., Lee, W. H., Jang, S. S., and Kang, C. W. (2017). "Polyethylene glycol treatment of Han-ok round wood components to prevent surface checking," BioRes. 12(2), 4229-4238.AbstractArticlePDF

    The effect of polyethylene glycol (PEG) treatment was investigated relative to surface checks of red and Korean pine round wood for building Korean-style homes. The logs used for this study were impregnated with a solution of PEG-1000 for three weeks, and then they were dried to a moisture content of about 15% at the temperature of 120 °C within the drying time of 49 h. During the middle stage of drying, slight surface checks were found on red pine PEG-treated logs compared with severe surface checks on red pine control logs. Due to PEG treatment and high drying temperature, at the end of drying, apparent surface check was not found on red pine PEG-treated logs compared with serious surface checks on the corresponding control log. No surface checks were discovered on Korean pine logs during and after drying due to the PEG effect. Thus, PEG treatment was effective in preventing surface checks on red and Korean pine logs during drying at high temperature.

  • Researchpp 4239-4258Hatam, A., Dehghani Firouzabadi, M., and Resalati, H. (2017). "Surface chemistry of gravure printed décor paper and adhesion of melamine formaldehyde resin coatings," BioRes. 12(2), 4239-4258.AbstractArticlePDF

    The surface chemistry of gravure printed décor paper and its effect on the adhesion of melamine formaldehyde (MF) coatings were studied. Two industrially printed decor papers with different designs were used for the study. A combination of the attenuated total reflectance Fourier transform Infrared (ATR FT-IR) and FT-IR spectroscopy techniques were employed to determine the effect of the gravure printing ink on the printed paper surface chemistry. Then, the influence of the surface chemistry on the adhesion of MF coatings was characterized according to the abrasion resistance test. The ATR IR results suggested that the printing ink components had a noticeable effect on the surface characteristics of the printed décor paper. In addition, it was indicated that the use of an organosilane adhesion promoter in the gravure ink formulation could significantly affect the adhesion strength of the MF coatings through the formation of ring siloxane structures. It seemed that siloxane bridges formed between the molecules of ink binder and UF resin could enhance the adhesion strength of subsequent MF coatings and could reveal better Taber abrasion resistance performance.

  • Researchpp 4259-4269Luo, Y. Y., Xiao, S. L., and Li, S. L. (2017). "Effect of initial water content on foaming quality and mechanical properties of plant fiber porous cushioning materials," BioRes. 12(2), 4259-4269.AbstractArticlePDF

    A porous, wood-fiber-based cushioning material for packaging was prepared in this study using poplar fiber and wood powder raw materials as an environmentally friendly resource. Water, the foaming agent azodicarbonamide and sodium bicarbonate, starch, and nucleating agent French chalk were used as additives, and the ingredients were subjected to hot-press molding. The effects of the initial water content on the foaming quality and mechanical properties of the plant fiber porous cushioning materials were explored. The results showed that the initial water content had a substantial influence on the foaming quality and mechanical properties of plant fiber porous buffer materials. When the initial water content was 69.3%, the initial embryo viscosity was the most suitable for bubble growth, and the porosity, pore size, and distribution of the samples were optimal. Furthermore, the mechanical properties of the samples were the strongest. The foaming mechanism of the plant fiber porous cushioning material was similar to the foaming mechanism of a polymer foaming material. Thus, the embryo viscosity had the greatest influence on the bubble growth process.

  • Researchpp 4270-4282Oktaee, J., Lautenschläger, T., Günther, M., Neinhuis, C., Wagenführ, A., Lindner, M., and Winkler, A. (2017). "Characterization of willow bast fibers (Salix spp.) from short-rotation plantation as potential reinforcement for polymer composites," BioRes. 12(2), 4270-4282.AbstractArticlePDF
    Short-rotation coppices have potential to be the future source of raw materials for many applications in the wood and paper industries. It is important to establish methods and products to handle their waste biomass. In this paper, the properties of bast fibers extracted from the bark of willow trees (Salix spp.) were evaluated for potential future use in the production of natural fiber-polymer composites. The anatomy of the fibers was investigated through optical and electron microscopy. The thermogravimetric analysis of these fibers showed that the major mass loss occurs at 257 °C. The density of the fibers was measured with a gas pycnometer (1.19 ± 0.2 g/cm3). The chemical analysis showed that willow bark fibers have a composition similar to willow wood. As an indicator of mechanical properties, single willow bast fibers were characterized by tensile tests. The results revealed values for tensile strength (307.6 ± 130.1 MPa) and Young’s modulus (16.9 ± 8.4 GPa) that are comparable to some commonly used natural fibers. The overall results showed that willow bast fibers have the required mechanical properties as well as thermal stability for application in reinforcement of polymers.
  • Researchpp 4283-4301Gurau, L., Irle, M., Campean, M., Ispas, M., and Buchner, J. (2017). "Surface quality of planed beech wood (Fagus sylvatica L. ) thermally treated for different durations of time," BioRes. 12(2), 4283-4301.AbstractArticlePDF
    Thermally treating wood improves its dimensional stability and durability. The chemical changes brought about by a heat treatment also affect the mechanical properties of wood. Consequently, a heat treatment also influences how a wood surface responds to machining. This study examined the impact of heat treatments at 200 C between 1 h and 6 h on the subsequent surface quality of planed beech wood (Fagus sylvatica L.). The new approach was that surface quality was assessed by following a tested method from previous research regarding the measuring and evaluation recommendations meant to reduce the biasing effect of wood anatomy, Also, a large number of roughness parameters were used for interpretation of the combined effect of processing and wood anatomy after filtering the data with a robust filter. Among those, Rk is the parameter that is least biased by wood anatomy and that best expresses the effect of processing alone. Electron micrographs were taken to visually assess the resultant surfaces. The results showed a gradual increase in processing roughness, as distinctively measured by Rk, which increased with longer durations of the treatment. Vessel cavities were deeper than those caused by processing and that influenced, among other parameters, Ra, which is most commonly used in literature to assess surface quality. The ray tissue, especially, exhibited both greater pull-out of fibers and a sort of plasticization with increased treatment time. The length of the thermal treatment reduced surface waviness. The results also showed that it was necessary to calculate the roughness parameters to differentiate between two similar surfaces rather than relying on visual and tactile assessments alone.
  • Researchpp 4302-4313Ma, Q., Han, L., Li, Q., Ma, S., and Huang, G. (2017). "Applicability of two separation methods for elemental analysis of typical agricultural biomass in China," BioRes. 12(2), 4302-4313.AbstractArticlePDF
    China still lacks standardized methods for element compositional analysis of agricultural biomass, in particular crop straw and livestock manure, which severely restricts the efficiency of the comprehensive utilization of agricultural biomass. Two separation methods, namely adsorbed–desorbed separation (AS) and chromatographic separation (CS), were applied to simultaneously analyze the carbon, hydrogen, nitrogen, and sulfur elements in major agricultural biomass. The optimal sizes of 1.00 mm for crop straws and 0.50 mm for livestock manure were obtained through optimization experiments. Afterwards, the sample mass was considered on two different elemental analysis instruments. From the metrological characteristics and variance analysis, a sample mass of 40 mg of the AS method was applicable for all the agricultural biomass, even with a content of 0.5%. On the other hand, 5 mg of the CS method was suitable for agricultural biomass with contents greater than 1.5%. It is recommended that samples should be kept free of impurities and completely homogeneous, especially for livestock manure. The results provide significant data for establishing a national standard system in the near future.
  • Researchpp 4314-4326Birkett, G. C., Sicoli, S., Horvath, L., Foster, J., Kim, Y. T., Renneckar, S., and Goodell, B. (2017). "Investigation of nanofibrillated cellulose for hydrophobic packaging material: Examining alternatives to solvent exchange and lyophilization," BioRes. 12(2), 4314-4326.AbstractArticlePDF
    A bio-based polyurethane and a thermosetting acrylic were tested in conjunction with nano-fibrillated cellulose and conventional kraft fiber to evaluate their use as a bio-derived, biodegradable packaging foam. Foams were evaluated for their density, water uptake, and compressive creep behavior. Bio-based urethane had a mean density of 68 kg/m3, mean water uptake of 4% in 24 h, and exceeded the 10% limit on compressive strain when tested at 71 °C and 22 °C, but remained below the limit when tested at -54 °C. The thermosetting acrylic had a mean density of 128 kg/m3, mean water uptake of 337% in 24 h, and showed less than 10% compressive creep at all three temperature conditions. The bio-derived urethane was able to incorporate 4% cellulose by mass, and the thermosetting acrylic was able to incorporate 48% cellulose by mass. In a 12-week test of biodegradation under fungal attack by Gloeophyllum trabeum and Rhodonia placenta, the urethane foam had < 3% mass loss and the acrylic foam had < 1% mass loss. The acrylic foams showed potential for durable packaging, particularly if they could be combined with a surface sealant that could be ruptured at the end of service life to promote degradation of the foam.
  • Researchpp 4327-4341Pourmousa, S. (2017). "Chemical oxygen demand and turbidity improvement of deinked tissue wastewater using electrocoagulation techniques," BioRes. 12(2), 4327-4341.AbstractArticlePDF

    The goal of this work was to evaluate the efficiency of electrocoagulation technique in deinked tissue industry wastewater. The effect of two types of electrodes, three electrolysis times, four voltages, and three pHs were investigated. Experiments were conducted in batch process using a glass cell. The chemical oxygen demand (COD) removal and turbidity improvement of wastewater were measured and evaluated through the independent and interaction effects of variables. The results revealed that both electrodes reduced the COD and turbidity. However, the ability of their performance depended on the electrolysis time, voltage, and pH. For COD, greater improvement by electrocoagulation technique was obtained with 45minute electrolysis time, 24 volts, and alkaline conditions, while the turbidity reduction was achieved at lower voltage. Analysis of the treated water showed that the maximum COD and turbidity removal efficiencies were 81.12% and 89.43%, respectively. The treated effluent was very clear, and its quality met the industrial applications. Consequently, the electrocoagulation technique can be considered a reliable and safe method for deinked tissue effluent treatments to replace the other chemical methods.

  • Researchpp 4342-4351Liu, X., Wu, Z., Zhang, J., and Ge, S. (2017). "Tensile and bending properties and correlation of windmill palm fiber," BioRes. 12(2), 4342-4351.AbstractArticlePDF
    Widely distributed in southern China, the windmill palm tree (Trachycarpus fortunei) is an important economic tree species from which palm fiber can be stripped. Palm Fiber (PF) is divided into palm leaf sheath fiber (PLSF) and palm petioles fiber (PPF), and both have good elasticity. These fibers can be used to produce mattresses and other elastic compound materials. While PLSF and PPF shared a similar elastic modulus, the elastic limit and elastic strain of PLSF were found to be significantly higher than that of PPF. Also, PLSF had superior tensile elastic properties. Within the elastic range, the bending and tensile properties of PF were almost the same. When given force under the horizonal-straight state, PLSF displayed superior bending elastic properties.
  • Researchpp 4352-4363Komesu, A., Wolf Maciel, M. R., Alves de Oliveira, R., and Maciel Filho, R. (2017). "Influence of residual sugars on the purification of lactic acid using short path evaporation," BioRes. 12(2), 4352-4363.AbstractArticlePDF

    Short path evaporation (SPE) is a promising separation technique for the purification of lactic acid from fermentation broth. This study investigated the influence of residual sugars, such as glucose, xylose, and sucrose, on the purification of lactic acid using SPE. A 23 factorial experimental design was performed in the experimental range from 5 g·L-1 to 15 g·L-1 for glucose, xylose, and sucrose concentrations. Glucose and sucrose concentrations did not have significant effects on the process of lactic acid concentration in the range used for this study. Xylose in high concentration was found to reduce the lactic acid concentration process performance. An increase in the boiling temperature of the mixture by the ebullioscopy effect possibly hindered the evaporation of the mixture.

  • Reviewpp 4364-4383Komesu, A., Oliveira, J. A. R. d., Martins, L. H. d. S., Wolf Maciel, M. R., and Maciel Filho, R. (2017). "Lactic acid production to purification: A review," BioRes. 12(2). 4364-4383.AbstractArticlePDF

    Lactic acid is a naturally occurring organic acid that can be used in a wide variety of industries, such as the cosmetic, pharmaceutical, chemical, food, and, most recently, the medical industries. It can be made by the fermentation of sugars obtained from renewable resources, which means that it is an eco-friendly product that has attracted a lot of attention in recent years. In 2010, the U.S. Department of Energy issued a report that listed lactic acid as a potential building block for the future. Bearing the importance of lactic acid in mind, this review summarizes information about lactic acid properties and applications, as well as its production and purification processes.

  • Reviewpp 4384-4409Bailón-Salas, A. M., Medrano-Roldán, H., Valle-Cervantes, S., Ordaz-Díaz, L. A., Urtiz-Estrada, N., and Rojas-Contreras, J. A. (2017). "Review of molecular techniques for the identification of bacterial communities in biological effluent treatment facilities at pulp and paper mills," BioRes. 12(2), 4384-4409.AbstractArticlePDF
    One of the processes most used in biotechnology today for handling industrial liquid wastes is biological wastewater treatment. The efficiency and quality of its operation depends on the composition and activity of the microbial community that is present. The application of traditional and molecular techniques has provided a glimpse into the “black box” and has given information to improve the wastewater treatment process. However, bleach pulp and paper mill effluents require a better understanding of the active bacterial population. For the study of these microorganisms, molecular techniques have been used for more than 15 years. However, there has been a lack of knowledge of the physiological requirements and relations with the environment, which seems to be very difficult to obtain involving profile on the diversity. Nowadays, high-throughput sequencing technology is a promising method that makes it possible to identify the entire profile of microbial communities. In combination with fingerprint methods, this approach allows the identification and analysis of the whole biodiversity of microbial communities. In this review, several identification techniques will be discussed.
  • Reviewpp 4410-4477Hubbe, M. A., Smith, R. D., Zou, X., Katuscak, S., Potthast, A., and Ahn, K. (2017). "Deacidification of acidic books and paper by means of non-aqueous dispersions of alkaline particles: A review focusing on completeness of the reaction," BioRes. 12(2), 4410-4477.AbstractArticlePDF

    Deacidification refers to chemical treatments meant to slow down the acid hydrolysis and embrittlement of books and paper documents that had been printed on acidic paper. From the early 1800s up to about 1990, papermakers used aluminum sulfate, an acidic compound, in most printing papers. Certain deacidification methods use non-aqueous media to distribute alkaline mineral particles such as MgO within the pages of the treated books. Evidence is considered here as to whether or not the proximity of alkaline particles within such documents is sufficient to neutralize the acidic species present. Because much evidence suggests incomplete neutralization, a second focus concerns what to do next in cases where books already have been treated with a non-aqueous dispersion system. Based on the literature, the neutralization of acidic species within such paper can be completed by partial moistening, by high humidity and pressure, by water condensation, as well as by optional treatments to enhance paper strength and a final drying step.

  • Reviewpp 4478-4489Mantanis, G. I. (2017). "Chemical modification of wood by acetylation or furfurylation: A review of the present scaled-up technologies," BioRes. 12(2), 4478-4489.AbstractArticlePDF

    Significant developments in the area of wood modification have been achieved during the last three decades. These developments can be attributed to increased environmental concerns, the escalating demand for a high and constant quality of wood products, and the rising prices of the durable tropical timber as well as its very limited availability, as affected by illegal logging. As a consequence, a number of wood modification techniques such as chemical and impregnation modifications or heat treatments have been introduced, and some of these technologies have reached the industrial level. This review paper deals with two successful technologies, that is, wood acetylation and wood furfurylation. It briefly discusses the advantages of the new modified products and presents in short their improved properties. Published findings indicate that chemical modification of wood, to a full or partial degree, by means of acetylation or furfurylation, offers a way to transform low durability wood species to new ‘green’ wood materials having advanced qualities and properties.