NC State
BioResources
  • Editorialpp 1-2Wang, P., Qian, X., and Shen, J. (2018). "Superhydrophobic coatings with edible biowaxes for reducing or eliminating liquid residues of foods and drinks in containers," BioRes. 13(1), 1-2.AbstractArticlePDF

    Biowaxes, including carnauba wax and beeswax, are edible and renewable. Once dispersed in a polar solvent, these natural materials could be easily converted into nontoxic, “roll-off”, and superhydrophobic coatings on the basis of spray coating. The combination of container materials with these coatings can reduce or even eliminate liquid resides (including highly viscous residues) of foods and drinks in containers (e.g., bottles), significantly facilitating downstream operations. Comprehensive demonstrations of this green concept would generate huge opportunities for food/drink-related industries.

  • Editorialpp 3-5Zhu, S., Yang, M., Luo, F., Yang, X., and Xue, Y. (2018). "Engineering cell wall-degrading enzymes into growing plants to improve lignocellulosic ethanol production," BioRes. 13(1), 3-5.AbstractArticlePDF

    The plant cell wall (PCW) represents the most abundant renewable biomass resource for lignocellulosic ethanol production. Economical and efficient degradation of PCW to fermentable sugars is an essential sub-process during lignocellulosic ethanol production. At present, the recalcitrance of PCW to various pretreatments and enzymatic hydrolysis makes the PCW degradation unacceptably expensive. Engineering cell wall-degrading enzymes into growing plants provides a promising solution to lower the PCW degradation cost and increase its degradation efficiency for lignocellulosic ethanol production. Avoiding damage by the expressed biomass-degrading enzymes to growing plants is the key to successful use of this method. Two modern biological technologies can be used to solve this problem. One is to engineer a thermoregulated intein-modified cell wall-degrading enzyme into growing plants. The other is to use the gene-timed expression technique. This editorial will give a brief discussion of opportunities and challenges of engineering cell wall-degrading enzymes into growing plants for improvement of lignocellulosic ethanol production.

  • Researchpp 6-14Wu, H., Yang, X., Rao, J., Zhang, Y., and Sun, F. (2018). "Improvement of bamboo properties via in situ construction of polyhydroxyethyl methylacrylate and polymethyl methylacrylate networks," BioRes. 13(1), 6-14.AbstractArticlePDF

    The chemical modification of bamboo culm was explored based on in situ construction of polyhydroxyethyl methylacrylate (PHEMA) and polymethyl methylacrylate (PMMA) networks into the cell walls. Scanning electron microscopy revealed that the synthesized polymers distributed in both the cell walls and the lumen with the pits blocked. The dimensional stability was tested under three water soaking-drying and moistening-drying cycles. The swelling efficiency of the treated bamboo was under 8% in three cycles of water soaking and drying cycles and was 4% in moistening-drying cycles. The anti-swelling efficiency was 60.5%, 52.7%, and 46.3%, respectively, in the moistening-drying cycles. Laboratory tests on mold resistance showed that no mycelium formed on the treated bamboo, while the untreated control was 100% covered by mold fungi.

  • Researchpp 15-26Avci, E., Acar, M., Gonultas, O., and Candan, Z. (2018). "Manufacturing biocomposites using black pine bark and oak bark," BioRes. 13(1), 15-26.AbstractArticlePDF

    Bark as a biowaste has a huge availability throughout the world and has had limited use in industrial applications. Black pine bark and oak bark were considered in this work. The aim was to manufacture a new biocomposite with different combination of black pine bark, oak bark, polypropylene, polyethylene, and a coupling agent, and to determine some physical and mechanical properties of the manufactured biocomposites. Density, thickness swelling, water absorption, tension strength, modulus of rapture and modulus of elasticity in bending and tension of the biocomposites were determined. According to the results, thickness swelling and water absorption properties were improved up to 80% when compared with wood-plastic composites (WPC) produced with wood flour. Although the new biocomposites displayed lower mechanical performance in comparison of biocomposites made with wood flour, the observed results were satisfactory. Based on the results of this study, black pine bark and oak bark can be used as filler materials in WPCs production. Hereby, these bark materials can be the raw material for value-added products. Bark use in biocomposite production also can contribute to reduced requirements of wood material and petroleum products.

  • Researchpp 27-42Li, J., Wang, B., Chen, K., Tian, J., Zeng, X., Xu, J., and Gao, W. (2018). "Optimization of pretreatment and alkaline cooking of wheat straw on its pulpability using response surface methodology," BioRes. 13(1), 27-42.AbstractArticlePDF

    The dissolution rates of the chemical compositions of alcohol-benzene extractables (ABE), holocellulose, hemicellulose, and lignin in wheat straw (WS) under different pretreatment conditions were investigated. The individual and interactive effects of three independent parameters, namely, sodium hydroxide (NaOH) dosage (x1: 8 wt.% to 12 wt.%), sodium sulfide (Na2S) dosage (x2: 10 wt.% to 18 wt.%), and time to maximum temperature (x3: 100 min to 140 min) on screened yield, Kappa number, and brightness of wheat straw pulp (WSP) were analyzed via response surface methodology (RSM). The results suggested that the quadratic equations were in good agreement with the experimental figures in the present work. The relative errors of verification results were less than 5%, which indicated that the selected model for explaining the relationship between the variables and the responses was correct. In addition, the relationships between the screened yield, reject yield, brightness, and Kappa number were described and explained. Wheat straw pulpability was optimized in this study via RSM.

  • Researchpp 43-52Hamdan, S., Abdul Wahid, H., Musoddiq, I., and Yohanes, N. (2018). "Marimba instrument construction from kayu malam wood (Diospyros maingayi)," BioRes. 13(1), 43-52.AbstractArticlePDF

    This work investigated the possibility of using a local wood Kayu malam (Diospyros maingayi) to construct a marimba, a musical instrument. The marimba was constructed as similar as possible to the commercial rosewood marimba. The sound and established frequencies were compared with a commercial rosewood marimba. The findings showed that although the peak value of the spectrum from the prototype marimba differs from pitch to pitch, it is useful to note that the prototype marimba was tuned according to piano standard. The commercial marimba only has peaks at the lower end of the spectrum whereas the prototype marimba contained peaks up until the higher end of its spectrum. The marimba made of Kayu malam (D. maingayi) produced the same pitch as the marimba made of rosewood.

  • Researchpp 53-70Inwood, J. P. W., Pakzad, L., and Fatehi, P. (2018). "Production of sulfur containing kraft lignin products," BioRes. 13(1), 53-70.AbstractArticlePDF

    Kraft lignin is produced in great quantities in many countries, but is mainly used as an energy source. To valorize its potential end-use applications, softwood kraft lignin was modified via sulfuric acid and sodium sulfite treatments in this study. The modification of kraft lignin through a sulfuric acid treatment resulted in a modified lignin (SA-lignin) with a charge density of 0.8 meq/g but with a limited water solubility. The sulfonation of the kraft lignin through a sodium sulfite treatment induced a soluble sulfonated lignin (SS-lignin) with a charge density of 1.4 meq/g, which was obtained under the conditions of 90 °C, 4 h, and 0.67 Na2SO3/lignin molar ratio. The elemental compositions, molecular weights, and thermal and rheological properties of modified lignin samples were characterized.

  • Researchpp 71-85Wang, Q., Xiao, S., Shi, S., and Cai, L. (2017). "Mechanical strength, thermal stability, and hydrophobicity of fiber materials after removal of residual lignin," BioRes. 13(1), 71-85.AbstractArticlePDF

    The behaviors of the mechanical, hydrophobic, and thermal properties of the molded fiber product (MFP) were examined after the removal of residual lignin. The fibers resulting from the chemi-thermomechanical pulping and bleaching processes were treated by extended delignification, namely by their reaction with glacial acetic acid and sodium chlorite. The changes in surface composition, chemical structure, crystallinity, microstructure, and thermal stability of the MFP were investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), respectively. Results showed that the composition and structure of carbohydrates on the fiber surface were not changed significantly, the lignin in fibers was almost completely removed, the relative content of intermolecular hydrogen bonds in cellulose and the contact area between fibers was increased, and the crystallinity index increased from 79.5% to 81.4% after the extended delignification. When the content of lignin decreased from 5.78% to 0.02%, the tensile strength of the MFP increased 25.6%, but little changes were found in the bending strength. The onset thermal decomposition temperature of MFP increased from 242 °C to 250 °C and the maximum rate of degradation temperature increased from 347 °C to 350 °C.

  • Researchpp 86-103Ramnath, L., Sithole, B., and Govinden, R. (2018). "The effects of wood storage on the chemical composition and indigenous microflora of Eucalyptus species used in the pulping industry," BioRes. 13(1), 86-103.AbstractArticlePDF

    Lipophilic extractives naturally occurring in wood tend to coalesce during pulping to form pitch deposits, which have particularly undesirable effects on the pulping process and quality of pulp produced. A chemical characterization of different eucalypt species [Eucalyptus nitens, E. grandis, and E. dunnii (of different site qualities)] wood and generated pulp was performed. This study aimed at determining the effects of wood storage at -20 °C (for 6 months), by examining their chemical composition and indigenous microflora. Fatty acids were the main lipophilic compounds among E. dunnii (SQ3 and SQ4) and E. grandis wood extractives. The wood of E. nitens posed the least risk for pitch deposit formation, making it the most suitable Eucalyptus species for pulping. Storage of wood chips at -20 °C had a similar effect as the traditional method of seasoning (storage of wood outdoors prior to pulping) used for the reduction of lipophilic extractives. A 25 to 44% reduction of total extractives was observed in the raw material after storage. Variations in bacterial and fungal communities were observed after storage, and should be taken into consideration when conducting lab scale trials. If storage of wood chips is necessary for lab testing, it should be retained for a maximum of 3 months at -20 °C.

  • Researchpp 104-114Částková, T., Hýsek, Š., Sikora, A., Schönfelder, O., and Böhm, M. (2018). "Chemical and physical parameters of different modifications of rape straw (Brassica napus L.)," BioRes. 13(1), 104-114.AbstractArticlePDF

    Material alternatives to wood, such as rape straw, are needed for the production of composite materials. This study performed an analysis of rape straw as a composite material source for production. There were three types of rape straw particle modification: untreated particles as reference variant, boiling in water, and soaking in sodium hydroxide (NaOH) solution. The pH and calorific value were highest for the variant soaked in NaOH. The total elemental content and the elements on the rape straw surface varied between variants. The modification method chosen influenced the pH, calorific value, elemental composition, and contact angle.

  • Researchpp 115-130Lee, C. S., Aroua, M. K., Wan Daud, W. A., Cognet, P., Pérès, Y., and Ajeel, M. A. (2018). "Selective electroreduction of glycerol to 1,2-propanediol on a mixed carbon-black activated carbon electrode and a mixed carbon black-diamond electrode," BioRes. 13(1), 115-130.AbstractArticlePDF

    1,2-propanediol was selectively produced by electroreduction of glycerol in a two-compartment reactor. Two new kinds of cathode electrodes were evaluated: (i) mixed carbon black-activated carbon electrodes and (ii) mixed carbon black-diamond electrodes. These electrodes were compared with a conventional platinum electrode. With a reaction temperature of 80 °C, an electric current of 2.0 A, and ambient pressure, the mixed carbon black-activated carbon electrode demonstrated excellent performance and successfully reduced glycerol to 1,2-propanediol with a high selectivity of 86% and 74% glycerol conversion.  The selectivity of 1,2-propanediol on the mixed carbon black-diamond electrode and the platinum electrode was 68% and 61%, respectively, with 88% glycerol conversion on the mixed carbon black-diamond electrode and 67% glycerol conversion on the platinum electrode. The authors propose a possible reaction mechanism for the formation of 1,2-PDO.

  • Researchpp 131-146Zhou, A., Bian, Y., Shen, Y., Huang, D., and Zhou, M. (2018). "Inelastic bending performances of laminated bamboo beams: Experimental investigation and analytical study," BioRes. 13(1), 131-146.AbstractArticlePDF

    Laminated bamboo (LB) is a processed bamboo-based composite fabricated by gluing bamboo strips under controlled temperature and pressure. It has many superior mechanical properties compared to commonly used wood products and is well suited for use as a construction material. The present work consisted of two parts. The first part aimed at studying the bending performances of LB beams. The stress-strain relationship of the LB composite had approximately perfect elasticity under tension, yet exhibited more complicated behavior under compression (i.e., linearity in the prior-proportional limit and nonlinearity in the post-proportional limit). The strength in tension was significantly higher than that during compression. Damage of LB beam began with the fiber yielding in the compressive zone until failure occurred when the fibers at the outermost part of the tensile zone broke. Hence, LB beams always underwent a long nonlinear process before failure. An empirical stress-strain relationship was proposed on the basis of a bilinear model. In the second part of the study, an analytical model for calculating the load-carrying capacity and deflection of LB beams was developed. Experimental results confirmed that the model had enough accuracy for design calculation.

  • Researchpp 147-156Köse Demirel, G., Güdül, H., Temiz, A., Kuştaş, S., and Aydın, İ. (2017). "Effect of alkyl ketene dimer on the physical, mechanical, and biological durability of plywood," BioRes. 13(1), 147-156.AbstractArticlePDF

    The effect of alkyl ketene dimer (AKD) on plywood properties was studied. AKD is widely used in the paper industry as a sizing agent and can esterify wood cell wall components. Two types of veneers obtained from alder (Alnus glutinosa subsp. barbata (C. A. Mey) Yalt.) and beech (Fagus orientalis L.) wood logs were used. Two different treatment processes and two different concentrations (1% and 3%) of AKD were tested. The first method was AKD-dispersion, which was mixed with glue and sprayed onto veneers. The second method was dipping veneers into the AKD solutions (1% and 3%) for 25 min. Water uptake after 2 h, 24 h, and 48 h was reduced by the AKD treatment. Plywood produced from AKD impregnated veneers showed the lowest thickness swelling versus untreated plywood and plywood produced from AKD blended in glue. The AKD treatment generally reduced the mechanical properties of the plywood. However, AKD treatment considerably improved the biological resistance against brown rot fungi (Coniophera puteana BAM Ebw. 15) and white rot fungi (Trametes versicolor CTB 863A). Increased methyl/methylene and carbonyl groups of the alkyl chain were determined in the Fourier transform infrared (FTIR) spectra of specimens subjected to the AKD-dispersion method.

  • Researchpp 157-170Čabalová, I., Kačík, F., Lagaňa, R., Výbohová, E., Bubeníková, T., Čaňová, I., and Ďurkovič, J. (2018). "Effect of thermal treatment on the chemical, physical, and mechanical properties of pedunculate oak (Quercus robur L.) wood," BioRes. 13(1), 157-170.AbstractArticlePDF

    Changes in the chemical composition and selected physico-mechanical properties of pedunculate oak (Quercus robur L.) wood samples were assessed after thermal treatment. Heat treatment was performed at 160, 180, and 200 °C in an oxidizing atmosphere. The contents of the extractives, lignin, cellulose, holocellulose, and saccharides, and the structural changes in the functional groups were determined. Changes in the colour traits, wood density, compression strength parallel to the grain, and compression modulus of elasticity were also determined. The decrease in the holocellulose content caused by the degradation of non-glucosic saccharides was observed during thermal treatment. The contents of both the extractives and lignin increased. The syringyl to guaiacyl (S/G) ratio in the lignin increased because of the preferential condensation of guaiacyl units. The physical and mechanical properties of pedunculate oak wood, such as density, equilibrium moisture content, colour lightness, and yellowness, decreased as the temperature increased. The compression strength and redness varied during thermal treatment, and reached maximum values during the treatment at 180 °C. The modulus of elasticity showed non-significant differences. Three groups of heat treatment clusters were distinguished in the multivariate wood trait analysis and were clearly segregated from each other.

  • Researchpp 171-175Mitchell, P. (2018). "Calculating the equilibrium moisture content for wood based on humidity measurements," BioRes. 13(1), 171-175.AbstractArticlePDF

    If given enough time, the moisture content of wood will reach an equilibrium with its surrounding environment. The temperature and relative humidity (RH) of the surrounding air will establish equilibrium moisture content (EMC) conditions, and the moisture content of the wood in that environment will approach a value determined by the RH. This article introduces an Excel spreadsheet that will calculate an estimate of the EMC based on any one of the following three pairs of data: RH and dry-bulb temperature, wet-bulb temperature and dry-bulb temperature, or dew-point temperature and dry-bulb temperature.

  • Researchpp 176-191Morais, I. L. H., Silva, C. M., Zanuncio, J. C., and Zanuncio, A. J. V. (2018). "Structural stabilization of granular sludge by addition of calcium ions into aerobic bioreactors," BioRes. 13(1), 176-191.AbstractArticlePDF

    Granulation is a gradual process that makes flocculent sludge granular through the simultaneous densification and selection of aggregates via sedimentation. The damage to the granule structure over time in a bioreactor operation is one of the most severe barriers to the practical application of the process. The addition of metal ions may increase aggregation rates and granular structure stability. Four sequential batch reactors fed with pulp mill effluent were operated and monitored. Three reactors contained aerobic granular sludge and one contained flocculent sludge. One granular sludge SBR received the addition of 100 mg∙L-1 of Ca2+, the second 200 mg∙L-1 of Ca2+, and the third received no intentional addition of calcium. The fourth SBR was operated with conventional flocculent sludge. The efficiency of the organic matter removal and the effect of calcium on the morphological characteristics of the granules formed were evaluated. The removal efficiency of the COD and the BOD was similar among all SBR, i.e., 60% and 90%, respectively. The addition of calcium did not interfere with granule size. The addition of 100 mg∙L-1 of Ca2+ increased the uniformity and the mechanical strength of the granules. It also increased approximately 36% of the settling velocity of the granules.

  • Researchpp 192-207Dang, C., Yin, Y., Xu, M., and Pu, J. (2018). "Hydrophobic noncrystalline porous starch (NCPS): Dispersed silver nanoparticle suspension as an antibacterial coating for packaging paper," BioRes. 13(1), 192-207.AbstractArticlePDF

    Hydrophobic noncrystalline porous starch (NCPS) containing microporous and amorphous structures was prepared from native corn starch via heat treatment, solvent exchange, and alkyl ketene dimer (AKD) modification. Then, antibacterial packaging was produced by combining silver nanoparticles with the hydrophobic NCPS (hydrophobic NCPS/Ag) and employing this biobased coating as a layer on the base paper. The antibacterial activity, strength, and barrier properties of the hydrophobic NCPS/Ag-coated paper were measured. In addition, the fine porous surface of NCPS, the distribution of the silver nanoparticles in hydrophobic NCPS as well as the network structure of uncoated paper and coated paper were characterized by scanning electron microscopy. Meanwhile, the hydrophobicity of the corn starch, hydrophobic NCPS, uncoated paper, and coated paper were determined using water contact angles. The silver nanoparticles had a positive effect on the antibacterial activity against Escherichia coli and Staphylococcus aureus. The air permeability, oil resistance, water vapor transmission rate, water absorption, whiteness, tensile strength, and burst strength improved compared to the uncoated paper.

  • Researchpp 208-219Yoshioka, K., Yamada, T., Ohno, H., and Miyafuji, H. (2018). "Production of furan compounds from Cryptomeria japonica using pyridinium chloride under various conditions," BioRes. 13(1), 208-219.AbstractArticlePDF

    Cryptomeria japonica was treated with pyridinium chloride ([Py]Cl)-water mixtures under various conditions to determine the optimum conditions for efficient production of furan compounds, such as 2-hydroxyacetylfuran (2-HAF), 5-hydroxymethylfurfural (5-HMF), and furfural. The maximum total yield of furan compounds, i.e., 9.24 wt.%, was obtained by the treatment of C. japonica with a 90% [Py]Cl and 10% water (w/w) solution for 30 min at 120 °C with a sample loading of 6 wt.%. The highest yield of 2-HAF from C. japonica was obtained by treatment for 3 min at 160 °C without the addition of water, although the total yield of furan compounds was lower than that obtained under the optimum treatment conditions. Scale-up of this process for efficient production of furan compounds from C. japonica was successfully performed under the optimum treatment conditions. In addition, the yields of 2-HAF and 5-HMF increased when ball-milled C. japonica containing low-crystallinity cellulose was treated under the optimum conditions.

  • Researchpp 220-230Lin, H., Sun, M., Li, J., Xu, Q., Yang, B., Wang, Q., Xie, W., Sun, S., Hu, K., and Zhang, L. (2018). "Purification and characterization of xylanase from spent mushroom compost and its application in saccharification of biomass wastes," BioRes. 13(1), 220-230.AbstractArticlePDF

    The activities of xylanase extracted from spent mushroom composts (SMCs) of Coprinus comatus, Auricularia auricular, Pleurotus ostreatus, Pleurotus citrinopileatus, Agrocybe cylindracea, Hericium erinaceus, Hypsizygus marmoreus, and Tremella fuciformis were investigated. The crude extract from T. fuciformis SMC showed high xylanase activity with a value of 255.2 U/mg. Furthermore, this xylanase was purified using a combination of ammonium sulfate precipitation, diethylaminoethyl-cellulose (DEAE-cellulose), and gel filtration column chromatography. The enzyme was purified 20.7-fold with a yield of 43.1% and activity of 5293.8 U/mg. The purified xylanase showed maximum activity at 50 °C and pH 6, retained 80% activity after 1 h incubation at 50 °C, and sustained stability over a wide range of pH values (2 to 10). Under the optimal conditions, the enzyme exhibited a Km value of 2.5 mg/mL towards birchwood xylan. The activity of xylanase was enhanced in the presence of Mg2+, Ca2+, Ba2+, NH4+, and Tween 80, while some metal ions, particularly Fe3+, inhibited its activity. The saccharification of several biomass wastes using the crude xylanase enzyme was studied. The results showed the potential for saccharification of alkaline-pretreated wheat bran solution where 75% saccharification was achieved.

  • Researchpp 231-240Wu, W., Jiang, B., Yang, L., and Jin, Y. (2018). "Isolation of lignin from Masson pine by liquid-liquid extraction based on complete dissolution in NaOH aqueous solution," BioRes. 13(1), 231-240.AbstractArticlePDF

    A method for lignin isolation from softwood based on complete dissolution in NaOH aqueous solution and liquid-liquid extraction was introduced. The structural features of milled alkali-soluble lignin (MAL) were comparatively analyzed with those of classical milled wood lignin (MWL) by means of alkaline nitrobenzene oxidation (NBO) and molecular weight, as well as Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectra analyses. The results showed that the yield of crude MAL (34.2%) was about twice as much as that of MWL (16.4%). The NBO product yields of MWL and MAL were quite similar. The weight-average molecular weight of MAL (10,400 g mol-1) was much higher than for MWL (6,970 g mol-1). Both MWL and MAL displayed similar FTIR, UV, 1H NMR, and 1H-13C HSQC NMR spectra. The total OH content of MAL (4.48 mmol g-1) was higher than that of MWL (3.89 mmol g-1). Compared with MWL, MAL showed similar structural characteristics but better isolation yield and higher molecular weight.

  • Researchpp 241-255Lee, J., Kim, S., Sim, K., Kang, D., and Youn, H. J. (2018). "Application of inorganic particles modified with polyvinylamine to produce antibacterial paper," BioRes. 13(1), 241-255.AbstractArticlePDF

    Antibacterial activity is one of the desired functionalities in paper and board grades, especially for packaging. This study designed a contact-active antibacterial surface using polyvinylamine (PVAm) bonded onto inorganic particles (kaolin), and investigated appropriate ways to utilize the treated inorganic particles as antibacterial carriers to produce antibacterial paper. Antibacterial inorganic particles were prepared by modifying the surface of kaolin through a polyelectrolytes multilayering (PEM) technique with a PVAm and polyacrylic acid system. The pH control during the PEM process affected the adsorption amount of PVAm and dispersion stability of PEM-treated kaolin. The PEM-treated kaolin was applied to prepared handsheets via two ways, internal addition or surface treatment. Only the surface-treated handsheets had a noticeably reduced bacteria ratio. Antibacterial activity was > 99.9% for Escherichia coli and > 99% for Listeria monocytogenes. The inactivation of bacteria with damaging membranes was confirmed by a dual staining method. The surface coverage of the PEM kaolin on the handsheets was an important factor for inactivation of the bacteria. As a result, the surface treatment of antibacterial inorganic particles was determined to be the proper strategy to produce antibacterial paper.

  • Researchpp 256-271Kılıç, H., Kasal, A., Kuşkun, T., Acar, M., and Erdil, Y. (2018). "Effect of tenon size on static front to back loading performance of wooden chairs in comparison with acceptable design loads," BioRes. 13(1), 256-271.AbstractArticlePDF

    The effects of tenon size were investigated relative to the front to back loading performance of Scots pine (Pinus sylvestris L.) chairs. Forty-five chair frames were constructed with mortise and tenon joints with 9 tenon sizes. Joints were assembled with a 65% solids polyvinyl acetate (PVAc) adhesive. The front to back loading performance of chairs was compared to the acceptable design load levels given in the American Library Association (ALA) specifications. Chair frames were structurally analyzed with the Finite Element Method (FEM) to obtain the moment acting on each joint under loading. The results indicated that a chair became stronger as either tenon width or length increased, but was most affected by its length. As a result of structural analyses, front leg to side rail and back leg to side rail joints carried approximately 73% of the total moment that was induced under the front to back loading. According to the comparison results with acceptable design loads, chairs constructed with 40 mm × 50 mm tenons could meet light service (domestic usage), while the chairs constructed with 50 mm × 50 mm tenons could meet medium service. The chairs constructed with other sizes could not meet any acceptable levels, and thus need reinforcement.

  • Researchpp 272-289Muniyadi, M., Ng, T. Y. S., Munusamy, Y., and Ooi, Z. X. (2018). "Mimusops elengi seed shell powder as a new bio-filler for polypropylene-based bio-composites," BioRes. 13(1), 272-289.AbstractArticlePDF

    Mimusops elengi seed shell powder (MESSP) was introduced as a new bio-filler in polypropylene (PP). The MESSP was characterized using a particle size analyzer, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and a thermogravimetric analyzer. MESSP was successfully melt mixed with polypropylene to produce bio-composite at various MESSP loading. The processability and properties of the bio-composites were characterized by using processing torques, differential scanning calorimetry, tensile test, water absorption, and SEM. The processability of PP was not affected by the addition of MESSP, which was revealed from the minimum changes in the processing torques, melting temperature, crystallization temperature, and degree of crystallinity. The tensile strength and elastic modulus of the bio-composites were improved with an addition of MESSP of up to 10 wt.%. However, the elongation at break and resistance to water absorption decreased slightly with increased MESSP loading. Morphological observations revealed that the MESSP showed good dispersion and adhesion in the PP matrix of up to 5 wt.% MESSP. Above 5 wt.% MESSP, agglomerates formed, which influenced the physical-mechanical properties of the PP and MESSP bio-composites. Results indicated that PP/MESSP composites can be used to replace PP in applications such as car dashboards and door panel, furniture, and rigid packaging.

  • Researchpp 290-298Li, X., Wu, N., Morrell, J., Du, G., Tang, Z., Wu, Z., and Zou, C. (2018). "Influence of hemp plant eccentric growth on physical properties and chemical compounds of hemp hurd," BioRes. 13(1), 290-298.AbstractArticlePDF

    The directions of South, North, West, and East had no significant influence on hemp hurd thickness (p > 0.05) based on the data from 100 hemp plants measured and oriented in different directions. As the hemp hurd grew, the thickness of the plants at different orientations also changed. The pectin and ash content in the wide areas were higher than those in the narrow areas. The lignin, holocellulose, alpha cellulose, and hemicellulose content in the wide areas were lower than those in the narrow areas (p = 0.05) in different hemp plants of different genders and plant densities. Additionally, the cell numbers in the wide areas were higher than those in the narrow areas in different locations of hemp plants, of different genders, and varied plant densities (p < 0.05). Thus, the formation of the narrow areas and wide areas in the hemp hurd were caused by the division difference of cambium. The plant hormones were the main influence on the division of cambium. Three particular plant hormones cytokinin (CTK), abscisic acid (ABA), and auxin (IAA) in the wide areas of hemp plants were higher than those in the narrow areas of plants of different genders and plant densities (p < 0.05). The eccentricity had a great influence on the physical and chemical properties of hemp hurd.

  • Researchpp 299-312Pan, M., Yan, J., Ding, C., Ma, W., Jin, J., Yuan, Y., and Chen, Y. (2018). "Study on the mass transfer enhancement in biofilms applied in papermaking wastewater treatment," BioRes. 13(1), 299-312.AbstractArticlePDF

    The research and refinement of papermaking wastewater treatment and reuse technology are important measures for energy conservation and emission reduction in the papermaking industry. This paper studied the process of biofilm formation and dissolved oxygen mass transfer of biofilms cultivated under different aeration intensities and attempted to enhance the biofilm reactor performance. The removal efficiencies of the chemical oxygen demand, total nitrogen, and ammonia nitrogen through biofilm treatment in two parallel biofilm reactors were higher under the larger aeration intensity (8 L/min) than under the smaller intensity (4 L/min). Macroscopically, this reflected the effect of dissolved oxygen on nitrogen removal. Microscopically, in terms of the dissolved oxygen profiles inside of the biofilms determined using a microelectrode probe, both aerobic and anaerobic layers occurred inside the biofilms, which suggested that simultaneous nitrification and denitrification occurred. The different aeration intensities led to differences in the internal and external dissolved oxygen concentrations in the biofilms, which affected the biofilm growth. This led to different micro-structures, and so the internal metabolism and wastewater treatment performance of the biofilms were not identical.

  • Researchpp 313-330Wang, X., Zhou, A., and Chui, Y. (2018). "Load-carrying capacity of intermediately slender parallel strand bamboo columns with a rectangular cross section under biaxial eccentric compression," BioRes. 13(1), 313-330.AbstractArticlePDF

    Parallel strand bamboo (PSB), a processed bamboo composite, has been used as an alternative to wood products in building and engineering applications. Inelastic analysis of PSB members is important because of the evident nonlinearity of the material. The present work conducted experimental investigations on intermediately slender PSB columns subjected to biaxial eccentric loads. The bending failure, which underwent a pronounced nonlinear process, was the major characteristic of the intermediately slender PSB column that had a biaxial compressive load. The mid-height cross section of the columns can be divided into three parts over its depth: the plastic compressive zone, the elastic compressive zone, and the tensile zone. Both the secondary bending and material nonlinearity were important factors that impacted the nonlinear response of the columns. An analytical method was presented for evaluating the load-carrying capacity of intermediately slender PSB columns with rectangular cross sections under biaxial eccentric compression loads. There was good agreement between the results of the experiments and calculations.

  • Researchpp 331-345Hosseinpourpia, R., Adamopoulos, S., and Mai, C. (2018). "Effects of acid pre-treatments on the swelling and vapor sorption of thermally modified Scots pine (Pinus sylvestris L.) wood," BioRes. 13(1), 331-345.AbstractArticlePDF

    Scots pine sapwood samples were pre-treated with a Lewis acid (AlCl3) and a combination of Lewis and protonic acids (AlCl3 and H2SO4), and were subsequently exposed to respective temperatures of 180 °C and 120 °C for establishing a comparable mass loss with those impregnated with demineralized water and solely thermally modified at 220 °C. Water impregnated samples dried at 120 °C also served as controls. The swelling behavior of all wood samples was examined with respect to maximum swelling in water, anti-swelling efficiency (ASE), shrinkage, and dynamic water vapor sorption at relative humidity ranges of 0% to 95%. The thermal modification at 220 °C diminished swelling and moisture adsorption, and also reduced moisture increment and decrement compared with the unmodified control. However, it was less obvious than both acid pre-treated samples. Excess surface work and Hailwood-Horrobin results calculated from water vapor sorption studies demonstrated that, at comparable mass loss, the available sorption sites were reduced to a greater extent by Lewis acid and combination of Lewis and protonic acids pre-treatment than the sole thermal treatment. This was attributed to more pronounced degradation of polysaccharides, mainly hemicelluloses and amorphous parts of cellulose, and to cross-linking of cell wall polymers due to the acid pre-treatments.

  • Researchpp 346-369Salzer, C., Wallbaum, H., Alipon, M., and Lopez, L. (2018). "Determining material suitability for low-rise housing in the Philippines: Physical and mechanical properties of the bamboo species Bambusa blumeana," BioRes. 13(1), 346-369.AbstractArticlePDF

    The use of cellulosic materials in the construction of low-rise housing in tropical climates has great potential. Bambusa blumeana (B. blumeana, J.A. and J.H. Schultes), the most abundantly available bamboo species in the Philippines, is a promising alternative material for the construction of cost-efficient buildings. However, to comply with municipal rules and regulations for construction, a comprehensive understanding of the organic raw material is needed to permit its application as a load-bearing structural member. In this study, the physical and mechanical properties of B. blumeana bamboo from a typical growth region of the Philippines were tested according to ISO 22157-1 (2004) and ISO 22157-2 (2004). The characteristic strength values of B. blumeana were as follows: compressive and tensile strengths parallel to the grain of 20 and 95 MPa, respectively; shear strength of 5 MPa, bending strength of 34.6 MPa, and the mean and fifth percentile modulus of elasticity of 13100 and 8600 MPa, respectively. Based on these results, a recommendation for permissible stresses for structural design was made in line with ISO 22156 (2004).

  • Researchpp 370-382Branowski, B., Zabłocki, M., and Sydor, M. (2018). "Experimental analysis of new furniture joints," BioRes. 13(1), 370-382.AbstractArticlePDF

    Load limit capacity, stiffness, and failure mechanisms were evaluated for the bending of two new types of furniture joints: one with an adhesive-bonded flat cross fastener, and the other with a frictional eccentric fastener. The results were compared with a commonly known direct thread connection used as a reference. For each of the three investigated types of joints, their strength-displacement curves and failure mechanisms were compared. The obtained results confirmed that the two new fasteners are suitable for making furniture joints with more advantageous load capacity and stiffness, as compared with the thread connection.

  • Researchpp 383-398Hu, K., Zhang, Z., Wang, F., Fan, Y., Li, J., Liu, L., and Wang, J. (2018). "Optimization of the hydrolysis condition of pretreated corn stover using Trichoderma viride broth based on orthogonal design and principal component analysis," BioRes. 13(1), 383-398.AbstractArticlePDF

    A new strategy is described to optimize multiple closely related parameters that are involved in the degradation of lignocellulose. Exo-β-1,4-glucanase, endo-β-1,4-glucanase, and β-glucosidase contained in the broth of Trichoderma viride 3.3711 cultures were used as enzyme solution. Corn stover (CS) pretreated by a combination of H2O2 and lignin peroxidase was used as raw feedstock. A comprehensive hydrolysis index (CHI) of three enzymatic activities was constructed by principal component analysis (PCA). Corn stover (CS) was pretreated with a combination of H2O2 and lignin peroxidase. The accuracy of the CHI was demonstrated by a quadratic regression using the CHI as an independent variable and the yield of the total reducing sugar (Ytrs) as a dependent variable. The results showed that the CHI was closely post-correlated with Ytrs and could be used to optimize the fermentation medium components for T. viride cultures due to a highly significant correlation between CHI and Ytrs. Based on the CHI at 96 h, an optimal medium contained 0.6% fructose, 0.6% xylose, 0.3% bean pulp, 0.15% yeast extract, 0.12% KH2PO4, 0.004% CaCl2, 0.008% FeSO4, 0.006% ZnSO4, 0.012% glycine betaine, and 0.004% polyethylene glycol. The maximum actual Ytrs was very near to the theoretical Ytrs.

  • Researchpp 399-411Li, X., Yang, L., Gu, X., Lai, C., Huang, C., and Yong, Q. (2018). "A combined process for production of fumaric acid and xylooligosaccharides from corncob," BioRes. 13(1), 399-411.AbstractArticlePDF

    Production of fumaric acid and xylooligosaccharides from corncob was investigated using a combined process. Corncob was fractionated into a cellulose-rich fraction and a hemicellulose-rich fraction by an alkali pretreatment. The cellulose-rich fraction was converted into fumaric acid by Rhizopus oryzae in fed-batch simultaneous saccharification and fermentation (SSF). Maximal fumaric acid concentration reached 35.22 g/L at a final 15% (w/v) solid loading in the fed-batch SSF. The hemicellulose-rich fraction was converted into xylooligosaccharides (XOSs) by endo-β-1,4-xylanase. The yield of XOSs was 62.35% after 24 h of xylanase hydrolysis. Xylobiose, xylotriose, and xylotetraose were the three major components in the XOSs. A mass balance analysis demonstrated that 100.6 g of fumaric acid and 148.1 g of XOSs were produced from 1000 g of dry corncob matter. The production of fumaric acid and XOSs by the combined process could make the utilization of corncob more efficient and more promising.

  • Researchpp 412-424Tayier, M., Duan, D., Zhao, Y., Ruan, R., Wang, Y., and Liu, Y. (2018). "Catalytic effects of various acids on microwave-assisted depolymerization of organosolv lignin," BioRes. 13(1), 412-424.AbstractArticlePDF

    The catalytic effects of various acids (sulfuric acid, hydrochloric acid, phosphoric acid, and formic acid) on the depolymerization of organosolv lignin under mild microwave heating (approximately 100 W, 160 °C for 30 min) were investigated. The liquid product was separated from the solid residue and analyzed by gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR). The solid residue was analyzed with thermogravimetric analysis (TG-DTG) and observed by scanning electron microscopy (SEM). The experimental results showed that sulfuric acid exhibited a better catalytic effect than the other acids. The SEM and TG-DTG results showed that the solid residue from sulfuric acid-catalyzed depolymerization was not only remarkably smaller than that of the other groups, but also presented a faster thermal decomposition rate. The molecular weight (Mw, weight-average) of the liquid product (Mw = 1020) from sulfuric acid-catalyzed depolymerization was also lower than that of the other groups.

  • Researchpp 425-436He, T., Liu, M., and Tian, X. (2018). "Kinetics of ozone bleaching of eucalyptus kraft pulp and factors affecting the properties of the bleached pulp," BioRes. 13(1), 425-436.AbstractArticlePDF

    Ozone is a non-chlorine bleaching agent that can reduce pollution in the pulp bleaching stage. In this work the ozone bleaching of eucalyptus kraft pulp was performed as part of a kinetics study to explain factors affecting the properties of bleached pulp. The bleaching efficiency was closely related to the rates of mass transfer and self-decomposition, as well as the intensity of ozonation. For ozone bleaching of 3% consistency pulp, a brightness of 68% ISO, viscosity of 579 mL/g, and kappa values of 7.9 were achieved under an optimal condition with pH 2 and organic reagent NP-10 supplied. In this condition, the ozone mass transfer and intensity of ozonation were promoted, while self-decomposition declined.

  • Researchpp 437-449Quan, G., Wang, H., Zhu, F., and Yan, J. (2018). "Porous biomass carbon coated with SiO2 as high performance electrodes for capacitive deionization," BioRes. 13(1), 437-449.AbstractArticlePDF

    The electrosorption capacity of an electrode strongly depends on the surface properties of the electrode material, such as the surface area, pore microstructure, and pore size distribution. Carbon-based electrode materials for capacitive deionization (CDI) or electrosorption processes suffer from problems with high manufacturing costs, poor electrical conductivity, and poor wettability. The thin-film coating of SiO2 on porous biomass carbon may provide an alternative electrode material for double-layer applications. In this paper, the activated porous biomass carbon (AWSC) was first obtained through a simple potassium hydroxide (KOH) activation of wheat straw carbon (WSC) as the precursor, and then thin-film SiO2 coated AWSC (SiO2@AWSC) was prepared by a sol-gel coating process. Scanning electron microscope (SEM) imaging of SiO2@AWSC demonstrated that a SiO2 thin-film was deposited on the surface of AWSC without changing the opening structure. Compared to WSC, the Brunauer-Emmett-Teller (BET) surface area of SiO2@AWSC was greatly increased, and presented obvious micropore and mesopore distributions. Further electrochemical analyses were performed via cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance. The electrochemical results showed that SiO2@AWSC electrodes showed increased electrosorption capacitance, which were attributed to a large specific surface area, a porous structure, and enhanced wettability.

  • Researchpp 450-461Li, P., Hou, Q., Zhang, M., and Li, X. (2018). "Environmentally friendly bleaching on bamboo (Neosinocalamus) kraft pulp cooked by displacement digester system," BioRes. 13(1), 450-461.AbstractArticlePDF

    The bleaching of pulp prepared by a displacement digester system (DDS) for displacement cooking of bamboo (Neosinocalamus) was established by comparing the results from elemental chlorine-free (ECF) bleaching and totally chlorine-free (TCF) bleaching. This process produced the optimal performance of obtained pulp via O-D0-EOP-D1 bleaching, where the Kappa number of DDS pulp was 18 to 22, and the Kappa number of oxygen delignified pulp was 10 to 12. The brightness of the obtained pulp was over 86% ISO, the yield was up to 46%, and the viscosity was approximately 800 mL·g-1. In contrast, O-Q-P1-P2 bleaching was advantageous for pulp with kappa number less than 5 after oxygen delignification. The brightness of obtained pulp was up to 81% ISO, the yield was over 40%, and the viscosity was about 650 mL·g-1. In TCF bleaching, the water consumption was 20 m3·t-1, the chemical oxygen demand (COD) content was 30 kg·t-1, and the absorbable organic halogen (AOX) content was zero. The water consumption of ECF bleaching was 4 times that of TCF bleaching, while the COD content was 16 kg·t-1 and the AOX content was 2 kg·t-1.

  • Researchpp 462-476Guy-Plourde, S., de Blois, M., Blanchet, P., Barbuta, C., and Robichaud, F. (2018). "Wood cladding in non-residential construction: Overcoming the barriers to leverage the opportunities," BioRes. 13(1), 462-476.AbstractArticlePDF

    Wood cladding is used in the residential market. However, the use of wood cladding in nonresidential and large multi-residential projects can sometimes be difficult. This paper highlights the barriers to the use of this material and draws recommendations to overcome them. A triangulation approach was used to enhance the validity of the findings with a deep literature review, interviews with different stakeholders, and analysis of several websites. The cross-compared analyses indicated that four main obstacles have hampered the use of wood cladding in non-residential projects. In order of importance, these obstacles are the recurring maintenance needed, restricting regulations (building code fire-safety and architecture implementation), appearance issues, and technical considerations regarding detailing and installation. To overcome the barriers of wood use in the non-residential market, three development axes are proposed based on communication with stakeholders, product adaptation for non-residential markets, and new product development with regards to product maintenance performance. These recommendations can guide manufacturers in adapting their product development strategies.

  • Researchpp 477-486Wu, G., Zhong, Y., Gong, Y., and Ren, H. (2018). "Mode II fracture toughness of bamboo scrimber with compact shear specimen," BioRes. 13(1), 477-486.AbstractArticlePDF

    The mode II fracture toughness of bamboo scrimber was evaluated. A compact shear specimen was chosen as the specimen, while the stress intensity factor KIIC was chosen as the index for the mode II fracture toughness. In total, 54 specimens containing two different grain modes and three different thicknesses were manufactured and subjected to static loading with specially designed loading clamps. The failure modes were observed, and the crack initiating loads were obtained. The stress intensity factor was calculated and analyzed. The failure of all specimens was due to brittleness and occurred instantaneously. Thus, the linear elastic fracture mechanics is applicable to the mode II fracture of bamboo scrimber. The stress intensity factor KIIC was 459.9 MPa·m1/2 for the F-L grain mode and 358.0 MPa·m1/2 for the S-L grain mode. There was no significant difference in the stress intensity factor KIIC of specimens where the thickness ranged from 10 mm to 30 mm; a specimen with a thickness of 10 mm can be used to determine the fracture toughness of the bamboo scrimber.

  • Researchpp 487-505Zaaba, N. F., and Ismail, H. (2018). "Comparative study of irradiated and non-irradiated recycled polypropylene/peanut shell powder composites under the effects of natural weathering degradation," BioRes. 13(1), 487-505.AbstractArticlePDF

    The properties of irradiated and non-irradiated recycled polypropylene (RPP)/peanut shell powder (PSP) composites were investigated relative to the effects of 6 months exposure to natural weathering. RPP/PSP composites were prepared by melt-mixing and compression molding with 0 to 40 wt.% PSP loading. The fabricated composites were then irradiated using a 2.0 MeV electron beam accelerator at a fixed dose of 20 kGy. The properties of non-irradiated and irradiated composites after exposure to natural weathering were compared and characterized by tensile properties, scanning electron microscopy (SEM), carbonyl indices (CI), differential scanning calorimetry (DSC), and weight loss analysis. The results in tensile strength and tensile modulus of irradiated RPP/PSP composites increased, while elongation at break decreased. The thermal stability of irradiated composites was also improved compared with non-irradiated composites. Pores and fungus penetration were observed from the SEM morphology, while an increase in carbonyl index and weight loss of both composites were evidenced that degradation occurred. The overall results indicated that the irradiated RPP/PSP composites were more resistant to natural weathering degradation than the non-irradiated RPP/PSP composites.

  • Researchpp 506-521Seo, H., Kim, N., Jo, J., and Lee, M. (2018). "Fire properties of Pinus densiflora utilizing fire-retardant chemicals based on borate and phosphorus (II) – Thermal and gas emission characteristics," BioRes. 13(1), 506-521.AbstractArticlePDF

    The pyrolysis characteristics of untreated pine and fire retardant-treated pine (Pinus densiflora) were measured by using thermogravimetric analysis according to the ASTM E1131-08 (2012) regulation. Fourier transform infrared spectroscopy was used to monitor changes in chemical groups of fire-retardant treated specimens before and after the combustion test. In addition, the microstructures of the untreated specimen and the fire-retardant treated specimen after cone calorimeter testing were determined by scanning electron microscopy. Combustion gas toxicity was evaluated according to the test method described in Naval Engineering Standard 713 (1990). The emitted combustion gases of all specimens were carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxide (NOX), and acrylonitrile. The thermal decomposition rate was reduced by about one-third that of the fire-retardant treated specimen compared to the reduction rate of the untreated specimen. These results are useful for guiding the safe utilization of fire retardant-treated wood and wood-based materials for building applications.

  • Researchpp 522-534Basarac Sertić, M., Pirc Barcic, A., and Klarić, K. (2018). "Economic determinants and analysis of the European Union wood industry SMEs employment," BioRes. 13(1), 522-534.AbstractArticlePDF

    Wood-based industries are an important part of the European Union (EU) manufacturing sector because their growth can help in achieving EU’s industrial policy goal of raising manufacturing’s gross domestic product (GDP) to 20% by 2020. In this paper, special emphasis is placed on the influence of macro-economic factors on small and medium enterprises (SMEs) employment in the wood industry. The research objective was to test whether traditional macroeconomic indicators of economic growth are significant determinates of SMEs employment dynamics. For estimation of employment dynamics, a two-step Arellano-Bover/Blundell-Bond (a system generalized method of moments) estimator with robust standard errors was used. The model contained the following independent variables: real GDP growth rate; industrial production of wood processing industry; the number of wood processing enterprises; and exporting of manufactured goods of wood processing. The findings confirmed that the increase in GDP growth rate, the industrial production of wood processing, and exporting of manufactured goods of wood processing had statistically significant and positive impacts on SMEs employment. It was also found that the existence of a high number of enterprises had a positive impact on employment.

  • Researchpp 535-554Muhamad Parid, D., Abd Rahman, N., Samsu Baharuddin, A., P. Mohammed, M., Mat Johari, A., and Abdul Razak, S. (2018). "Synthesis and characterization of carboxymethyl cellulose from oil palm empty fruit bunch stalk fibres," BioRes. 13(1), 535-554.AbstractArticlePDF

    The current extraction of carboxymethyl cellulose (CMC) from wood has created competition with wood industries. Interest in alternative sources is critical to ensure the sustainable production of CMC. Therefore, the extraction of CMC from oil palm empty fruit bunch (OPEFB) stalk fibres was evaluated. CMC extracted from OPEFB stalk fibres was characterized for chemical composition as well as by spectroscopic, microscopic, physicochemical, and rheological tests. Highest cellulose content was obtained from raw stalk fibres with the least amount of lignin and residual oil as compared to the empty fruit bunch (EFB) and spikelet. The XRD analysis revealed that the native cellulose was transformed into an amorphous phase, as evidenced from the characteristic peaks that had almost disappeared. Likewise, the FTIR analysis showed that major peaks in the lignin and hemicellulose were absent, which enabled the cellulose to be converted to CMC. Microscopy analysis showed notable changes in the fibres’ morphology throughout the extraction process. In addition, X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), physicochemical studies, and rheological tests on extracted CMC showed that there was a significant difference between each phase of the extraction process and this showed that OPEFB stalk fibre was feasible to produce CMC that was comparable to those of commercial CMC.

  • Researchpp 555-568Brenci, L. M., Cosereanu, C., Zeleniuc, O., Georgescu, S. V., and Fotin, A. (2018). "Thermal conductivity of wood with ABS waste core sandwich composites subject to various core modifications,"  BioRes. 13(1), 555-568.AbstractArticlePDF

    Five types of alternative sandwich composite structures designed for building walls were investigated in this study using various core materials such as wood shavings, recycled acrylonitrile butadiene styrene panels, and rock wool. The sandwich structures were designed for exterior walls with a thickness of 175 mm. The experiment simulated the conditions for inside and outside temperatures during winter and summer seasons. The thermal conductivity coefficient associated with winter was lower by about 55% than those registered for summer. Wood shavings and one ABS panel as core components led to the most thermally stable structure. The best insulation solutions were the rock wool core structures with a mean thermal conductivity coefficient between 0.0564 W/mK and 0.0605 W/mK for the entire testing cycle. The two ABS panels from the core configurations had a negative impact on the thermal performance. The lowest thermal performance was recorded by the pure wood shavings core structure, with a maximum value of thermal conductivity coefficient of 0.150 W/mK. Compressed wood shaving core structures can compete with rock wool as thermal insulation solution.

  • Researchpp 569-585Contreras-Hernández, M. G., Aréchiga-Carvajal, E. T., Moreno-Jiménez, M. R., González-Herrera, S. M., López-Miranda, J., Prado-Barrágan, L. A., and Rutiaga-Quiñones, O. M. (2018). "Enzymatic potential of native fungal strains of Agave residues," BioRes. 13(1), 569-585.AbstractArticlePDF

    Twelve strains of fungi from residues of Agave durangensis were isolated and identified by molecular techniques for evaluation of their hydrolytic enzyme production capability. A proportion (50%) of the fungal strains belonged to the Aspergillus genus and the other strains used belonged to Alternaria, Neurospora crassa, Mucor sp, Rhizopus sp., Botryosphaeria sp., and Scytalidium sp. The isolated strains were evaluated for their potential to produce extracellular enzymes using different substrates (cellulose, xylan, inulin, Agave fructans, starch, and tannic acid). It was observed that most of the tested strains were capable of simultaneously secreting cellulases, xylanases, inulinases, fructanases, and laccases. Botryosphaeria sp. ITD-G6 was selected for its evaluation in the production of inulinase, using different substrates. Showing high inulinase activities (5.22 U / mL for Agave waste, 4.37 U/ mL for inulin and 5.00 U / mL for Agave fructans).

  • Researchpp 586-596Berti, S., Burato, P., Dionisi-Vici, P., and Allegretti, O. (2018). "Orange wood for parquet and engineered flooring use," BioRes. 13(1), 586-596.AbstractArticlePDF

    Orange is a fruit of the Citrus genus in the family Rutaceae. It is assumed to have originated in southern Asia, and to have been first cultivated in China around 2500 BC. There is little knowledge on the quality of wood from orange trees, which is occasionally used in fine woodwork, tool handles, mosaics, and marquetry. This work aimed to evaluate the possibility of using orange wood from agricultural conversions and orchard plantation renewals to make products with a high value. Logs from plantations located in southern Italy were collected, and the key aspects for determining the suitability of using the wood as flooring were examined. Laboratory tests were carried out to determine the shrinkage, dimensional stability, and surface hardness, which included an indentation test on the wood flooring. Drying trials were also performed, and prototypes of flooring were prepared so professionals and end users could evaluate the aesthetic value. The results confirmed that the wood from orange trees is fine-grained, and is characterized by a high density and shrinkage, average dimensional stability, and high surface hardness. The results of the tests suggested performing careful drying and following specific procedures according to the size of the elements. The wood was highly appreciated by the users, which confirmed the possibility of using this wood as a renewable raw material, despite the limited availability, for manufacturing high-quality products.

  • Researchpp 597-631Song, W., Xu, Z., and Zhang, S. (2018). "Using surface modified E-glass fiber cloths to enhance poplar laminated veneer lumber composites: Effects of modification conditions, gluing processes, hot-pressing parameters, and assembly patterns on physical-mechanical and interfacial properties," BioRes. 13(1), 597-631.AbstractArticlePDF

    To develop construction and building materials from low-quality fast-growing wood, poplar laminated veneer lumber composites reinforced by E-glass fiber cloths (GFC) were prepared with phenol-formaldehyde adhesives. The GFCs were modified with γ-aminopropyltriethoxysilane solution (concentration: 0.8%, 1.3%, and 1.8%). Between each veneer, 260, 330, or 400 g/m2 adhesives were spread on one or both sides of veneers. The composites were hot-pressed under different temperatures (130, 145, and 160 °C) and gauge pressures (0.7, 1.2, and 1.7 MPa). The GFC dosages and positions in composites were varied. To evaluate the effects of variables on composites, analytical methods included the contact angle, scanning electron microscopy, and physical-mechanical measurements (flexural strength, flexural modulus, horizontal shear strength, internal bond strength, thickness swelling, and dip peel). The results showed that γ-aminopropyltriethoxysilane made GFC more hydrophilic and compatible with adhesives, enhancing their interfacial adhesion. Considering most of the physical-mechanical and interfacial properties, the optimum parameters for preparing composites were determined to be 1.3% (γ-aminopropyltriethoxysilane), 330 g/m2 (adhesive, double-sided gluing), 160 °C (temperature), and 1.2 MPa (pressure). Varying GFC dosages and positions in composites had positive or negative effects on different physical-mechanical properties. Models were developed to correlate flexural data with GFC dosages and positions.

  • Researchpp 632-645Tarzia, A., Montanaro, J., Casiello, M., Annese, C., Nacci, A., and Maffezzoli, A. (2018). "Synthesis, curing, and properties of an epoxy resin derived from gallic acid," BioRes. 13(1), 632-645.AbstractArticlePDF

    An aromatic epoxy monomer, formed by glycidylation of gallic acid, was crosslinked by adopting different curing agents to obtain bio-based, crosslinked resins with suitable engineering properties. Specifically, tri- and tetra-glycidyl ether of gallic acid (GEGA) were obtained using a two-step synthesis. These bio-based monomers were cured in the following three epoxy formulations: a stiff cycloaliphatic primary amine, isophorone diamine, and a flexible polypropylene oxide amine (Jeffamine D-230). Next, the homopolymerization of GEGA was studied using an ionic initiator, N,N-dimethylbenzylamine, and a complex curing mechanism highlighted by calorimetric and mass spectra analysis. Calorimetric and rheological measurements were used to compare the curing behavior of the studied GEGA-based formulations. Mechanical properties of the gallic acid-based epoxy resins were comparable with those of standard epoxy resin formulations, based on di-glycidyl ether of bisphenol A. Thermogravimetric analysis of cured samples showed a relevant char content at high temperatures.

  • Researchpp 646-661Rudak, P., Barcik, S., Ekevad, M., Rudak, O., Vanco, M., and Stefkova, J. (2018). "Motion of chips when leaving the cutting zone during chipboard plane milling," BioRes. 13(1), 646-661.AbstractArticlePDF

    Mathematical equations were established and the following regularities of the plane milling process of wood materials were analyzed: effect of the cutting edge inclination angle on chip exit angle, influence of cutting edge inclination angle on speed of chip movement along the blade and exit speed of the chips from the cutting zone, dependence of the chip exit angle on the friction coefficients of the chips on the processed material surface and along the blade surface (friction coefficients were determined from the results of experimental measurements), and influence of mill rotation frequency on the chip exit angle. The milling of the chipboards with various mill designs was performed at different cutting parameters (diameter = 7 mm to 32 mm, number of cutting edges = 1 to 4, cutting edge inclination angle = -5° to 20°, frequency of mill rotation = 3000 min-1 to 24000 min-1, feed per tooth = 0.1 mm to 1.5 mm). The process of chip exit from the cutting zone was photographed, and the chip exit angles were measured. A comparison of the chip exit angle values obtained from the experiments with those from the calculations based on the developed mathematical equations showed a high convergence.

  • Researchpp 662-677Terzi, E., Kartal, S., Muin, M., Hassanin, A., Hamouda, T., Kılıç, A., and Candan, Z. (2018). "Biological performance of novel hybrid green composites produced from glass fibers and jute fabric skin by the VARTM process," BioRes. 13(1), 662-677.AbstractArticlePDF

    Environmentally friendly composites are increasingly used in building applications that require fungal and insect resistance. This study evaluated the ability of both wood-degrading and mold fungi to decompose hybrid composites made of wood furnish, glass fibers, and jute fabric skin. Fungal decay resistance tests employed brown-rot fungus (Fomitopsis palustris) and white-rot fungus (Trametes versicolor). Mold resistance tests were performed with a mixture of three mold fungi, Aspergillus niger, Penicillium chrysogenum, and Trichoderma viride. The test specimens were also bio-assayed against termites in both laboratory and field conditions. When compared to control composites specimens produced by conventional methods without glass fiber and jute, the specimens with/without glass fiber and jute fabric manufactured by the VARTM process showed high resistance against the wood-degrading fungi and termites under laboratory and field conditions; however, mold fungal growth was observed on the surfaces of the specimens with 10%, 15%, and 20% glass fiber (without jute fabric) and with 5%, 10%, and 15% glass fiber (with jute fabric). In geographical locations with severe decay and termite hazards, these composite products may have a long service life as alternatives to conventional composites.

  • Researchpp 678-690Jamnicki Hanzer, S., Rožić, M., Vukoje, M., Jukić, M., and Galić, A. (2018). "Safety evaluation of deinked pulp containing offset thermochromic inks," BioRes. 13(1), 678-690.AbstractArticlePDF

    Evaluating the safety of thermochromic inks for offset lithography in deinked pulp samples is a major area of investigation. In this study, three offset inks were analyzed – one that dries by absorption and two that dry by oxypolymerization of vegetable oils. Inks were printed separately on strips of white uncoated paper, and the prints were recycled by chemical deinking flotation. Thermochromic inks, handsheets, filter pads, and process waters obtained from deinking were tested for the presence of heavy metals, while concentrations of bisphenol A (BPA), total organic compounds, and antimicrobial agents were examined in handsheets and filter pads. The concentration of heavy metals cations was determined from ashes of undeinked and deinked pulp handsheets as well as from ashes of blank paper, flotation froth, and process water filtrates. BPA originates from thermochromic inks, and a 50% reduction of BPA was noticed in the samples after flotation. Considering the results, deinked pulp is undesirable due to the presence of BPA. Despite the presence of BPA, there was no release of toxic components from deinked pulp.

  • Researchpp 691-703Liu, L., Zhang, S., Yang, X., and Ju, M. (2018). "Cellulose isolation from corn stalk treated by alkaline biochars in solvent systems," BioRes. 13(1), 691-703.AbstractArticlePDF

    Three kinds of biochars were prepared using corn stalk as the raw material. Corn stalk degradation was achieved in solvents by treatment with prepared biochars for 5 h at 170 °C. The solvent systems contained ionic liquid and water components, which presented synergistic effects on lignocellulosic degradation. The oxidized alkaline biochar (B2) was most effective for the lignin degradation in corn stalk, which promoted corn stalk dissolution into the reaction system. For treated corn stalk, both the lignin and hemicellulose were degraded during the reaction under the combined effects of biochars and nucleophilic components in solvents, and cellulose dissolution was enhanced. Dissolved cellulose was regenerated by mixing ethyl acetate and water gradually.

  • Researchpp 704-714Feng, N., Fu, Y., Wang, C., and Wu, Q. (2018). "An effective modification with mild alkali pretreatment for enhancing the biodegradation of wheat straw by Pycnoporus sanguineus NFZH-1," BioRes. 13(1), 704-714.AbstractArticlePDF

    A delignification pretreatment is important for enhancing lignocellulose biodegradation. Alkali pretreatment is a promising approach. Fiber morphology, alkaline nitrobenzene oxidation, and ozonation were used to characterize the wheat straw modified by mild alkali pretreatment (2% sodium hydroxide (NaOH) at 121 °C for 30 min), and for studying the advantageous performance by Pycnoporus sanguineus NFZH-1 in the aspects of lignin and carbohydrate biodegradation. The results indicated a powerful and selective delignification in the mild alkali pretreatment process. The relative contents of the G unit and the T form both decreased with mild alkali pretreatment. Meanwhile, epicuticular wax removal and increased porosity was observed in the fibrous tissue of alkali-treated wheat straw. Thus, the biodegradation of the Klason lignin in alkali-treated wheat straw was clearly enhanced and reached 41.4% during the following 10 days of fermentation with P. sanguineus NFZH-1. In addition, the modification of fiber tissue with a mild alkali pretreatment enhanced the biodegradation of xylan. The biodegradation of the chemical constituents of the wheat straw was enhanced by the effective modification with a mild alkali pretreatment. The enhanced biodegradation will be helpful for improving the efficiency of straw return.

  • Researchpp 715-728Jebrane, M., Pockrandt, M., Cuccui, I., Allegretti, O., Uetimane Jr., E., and Terziev, N. (2018). "Comparative study of two softwood species industrially modified by Thermowood® and thermo-vacuum process," BioRes. 13(1), 715-728.AbstractArticlePDF

    Scots pine and Norway spruce, the most used commercial wood species in Europe, were thermally treated under industrial conditions by steam (Thermowood®) and vacuum (Termovuoto). Matched boards were treated, and the alterations in chemistry, color, mass loss, mechanical properties, and durability were compared. In treatments at identical temperature and duration, Thermowood® and the thermo-vacuum process caused similar mass loss in both wood species. The thermal treatments showed minor effects on the released acetic acid during the thermal degradation of polysaccharides. The equilibrium moisture content correlated well with the mass loss and confirmed indirectly the similarity of the two processes. The chemical composition and durability of the two groups of treated wood were similar. In conclusion, Thermowood® and thermo-vacuum treatments according to Termovuoto technology both produce similar final products with regard to chemical composition, physical-mechanical properties, and durability, with some differences in the appearance.

  • Researchpp 729-739Chen, Q., Dong, X., Zhou, L., Zheng, X., Wang, J., and Wang, P. (2018). "Nanostarch surface coating of lightweight coated paper," BioRes. 13(1), 729-739.AbstractArticlePDF

    Nanostarch has a small particle size and large surface area compared with traditional modified starch. In this study, nanostarch was prepared by dual screw extrusion and was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and X-ray diffraction (XRD). The nanostarch was studied as a coating adhesive in surface coating of lightweight coated paper. The crystallinity of nanostarch granules was decreased by dual screw extrusion, and its average particle size was about 100 nm. The results showed that for the paper coating formula of styrene butadiene latex and an ordinary oxidized coating starch ratio of 9:5, all ordinary oxidized coating starch and part of the styrene butadiene latex can be replaced by nanostarch. When 5 parts of ordinary oxidized coating starch and 4 parts of styrene butadiene latex were replaced by 6.5 parts nanostarch, the water retention property of nanostarch coating was increased by 64.0%, and its viscosity was decreased by 11.0%. The IGT printing surface strength of lightweight coated paper by the nanostarch coating was increased by 11.6%, and the glossiness of coated paper was increased by 7.2%. These results show that nanostarch surface coatings have good prospects for application in papermaking.

  • Researchpp 740-751Xu, D., Qian, S., Zhang, F., Tong, G., and Ren, H. (2018). "Preparation of composite films of methacryloyl-modified lignocresol and polylactic acid," BioRes. 13(1), 740-751.AbstractArticlePDF

    Methacryloyl chloride was grafted onto lignocresol to increase the acyl content of lignocresol and to enhance the interfacial compatibility of lignocresol and polylactic acid. The physical and mechanical properties of the modified lignocresol sample were studied. The methacryloyl-modified lignocresol was characterized by infrared spectroscopy (IR), ultraviolet-visible (UV) spectroscopy, and gel permeation chromatography (GPC). Unmodified and modified lignocresol samples were used to prepare composite films with polylactic acid, and its tensile strengths and elongations at breaks were analyzed after film formation. Thermal stabilities were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results indicated that methacryloyl group was successfully grafted onto lignocresol, and that the optimum dosage of methacryloyl chloride required was 0.5 mL per 0.5 g of lignocresol. When unmodified lignocresol was added to polylactic acid, the tensile strength gradually decreased as the amount of lignocresol increased. However, the composite films prepared from the methacryloyl-modified lignocresol exhibited a slower decline in tensile strength and displayed an increased elongation at break. The optimum mechanical properties were found using a 10% blend of modified lignocresol with polylactic acid.

  • Researchpp 752-763Batool, I., Gulfraz, M., Asad, M., Kabir, F., Khadam, S., and Ahmed, A. (2018). "Cellulomonas sp. isolated from termite gut for saccharification and fermentation of agricultural biomass," BioRes. 13(1), 752-763.AbstractArticlePDF

    Biofuel is an important alternative source of fuel, as many countries are looking to decrease their dependence on fossil fuels. One of the critical steps in biofuel production is the conversion of lignocelluloses to fermentable sugars, and there is need for cheaper and more efficient enzymatic strategies. Consequently, lignocellulase genes from various organisms have been explored. Termites possess varied sets of efficient micro-scale lignocellulose degrading systems. In this study, bacteria that degraded cellulose and xylan were isolated from termite gastrointestinal tract. The isolate was identified as Cellulomonas sp. by 16S rRNA gene sequencing. The bacterial enzymes cellulase and xylanase showed the highest activity at 50 °C and pH 8.0. The agricultural substrates were hydrolyzed by cellulases and xylanases, and more sugar was released from corn stover (18.903+0.65 mM/L) than from rice straw or cotton stalk. After direct hydrolysis and fermentation of agricultural substrates, ethanol (0.425+0.035 g/L) and lactate (0.772+0.075 g/L) were the major end products. Thus, termite gut bacteria can efficiently hydrolyze hemicellulose and cellulose, and these bacteria also have the potential to convert these fermentable sugars into valuable secondary metabolites.

  • Researchpp 764-775Wen, M., Sun, Y., Shi, J., and Park, H. (2018). "Changes in physical properties of Sugi, Hinoki, and Korean pine wood after fire-retardant treatment," BioRes. 13(1), 764-775.AbstractArticlePDF

    The effect of a fire-retardant treatment on some physical properties, including dimensional stability, hygroscopicity, and surface color variation of Sugi (Cryptomeria japonica), Korean Pine (Pinus koraiensis), and Hinoki (Chamaecyparis obtusa) were investigated in this study. These softwoods were subjected to vacuum-pressure and impregnated with a developed fire-retardant chemical. The results showed that the radial and tangential swelling of 1% moisture content (MC) increment were lower for all three wood species compared with the control specimen after the fire-retardant treatment, despite higher equilibrium moisture content (EMC) at 75% relative humidity (RH) and 90% RH at 40 °C. Meanwhile, the bulk coefficient after water immersion decreased for all specimens after the treatment, which indicated higher dimensional stability. However, the fire-retardant treatment proved a shift in surface color to darkness.

  • Researchpp 776-788Slabejova, G., Smidriakova, M., and Panis, D. (2018). "Quality of silicone coating on the veneer surfaces," BioRes. 13(1), 776-788.AbstractArticlePDF

    The surface quality of silicone resin coating on the veneer surface was evaluated. Silicone resins of various types (weakly, moderately, strongly hydrophobic, and hydrophilic resins) were applied on veneer and cured. The quality of the coatings was assessed according to the impact resistance of the surface and the resistance to cold liquids (acetic acid, citric acid, ethanol, sodium carbonate, sodium chloride, cleaner SAVO). The gloss value of silicone coatings on the veneer surface was determined from the aesthetic qualities. Radially sliced beech, oak, walnut, and ash veneers were tested. Veneer surface roughness was measured before and after modification with the silicone resins. The results obtained show that after modification by silicone resins, the surface roughness of the veneers was not significantly different from that of resin-free veneers. Impact resistance testing showed that intrusions on veneer surfaces with silicone coatings were free of cracks visible to the naked eye. Surface resistance to cold liquids on the surfaces with silicone coatings was lower if compared to that of commonly used coatings. In some cases, the surfaces showed strong damage, mostly without changing the structure of the coating, after only 10 min exposure to cold liquid. The gloss value of silicone coatings on wood veneers was graded as matte to semi-gloss.

  • Researchpp 789-803Gao, Y., Hua, J., Cai, L., Chen, G., Jia, N., Zhu, L., and Wang, H. (2018). "Modeling and optimization of fiber quality and energy consumption during refining based on adaptive neuro-fuzzy inference system and subtractive clustering," BioRes. 13(1), 789-803.AbstractArticlePDF

    Refining is a critical step in the manufacturing of medium-density fiberboard (MDF). To ensure fiber quality and control of the energy consumption during refining, proper production parameters, such as feeding screw revolution speed (SR), accumulated chip height (CH), opening ratio of the discharge valve (OV), and content of Chinese poplar (CP), are vital. These parameters were monitored and recorded in an MDF mill to investigate the relationships between the parameters and the fiber quality and energy consumption. In this study, fuzzy models of the fiber quality and the energy consumption during refining were established based on subtractive clustering and an adaptive neuro-fuzzy inference system (ANFIS). The fiber quality and energy consumption models demonstrated high prediction accuracy because their predictive mean relative errors were as low as 4.14% and 6.72%, respectively. The errors of fiber quality were optimized using the simulated annealing method, and the input parameters were obtained. Based on the energy consumption model, the minimum energy consumption was 41.51 kWh/t, on the premise of the minimum requirement of fiber quality. This study can be a guideline for MDF production management to improve fiberboard quality and reduce energy consumption.

  • Researchpp 804-819Giagli, K., Baar, J., Fajstavr, M., Gryc, V., and Vavrčík, H. (2018). "Tree-ring width and variation of wood density in Fraxinus excelsior L. and Quercus robur L. growing in floodplain forests," BioRes. 13(1), 804-819.AbstractArticlePDF

    Oven-dry wood density variations are reported for European ash (Fraxinus excelsior L.) and English oak (Quercus robur L.) trees growing in floodplain mixed forests in South Moravia, Czech Republic. Two sites with different water regime conditions were selected along the Dyje (site A) and the Morava (site B) Rivers. In total, 20 dominant, healthy trees were chosen to determine the tree-ring structure and the oven-dry wood density (ρ0) along the radius of the stem cross section. The tree-ring width followed the common trend of a general decline as the trees aged. After removing the age influence, significant differences were observed in the tree-ring structure, recorded several years after water regime treatments. The European ash and the English oak ρ0 were found to be 677.3 kg∙m-3 and 618.2 kg∙m-3, respectively, significantly differing between the sites, for both species. High variability of ρ0 was also noticed along the stem radius in both species and sites.

  • Researchpp 820-835Langhorst, A., Burkholder, J., Long, J., Thomas, R., Kiziltas, A., and Mielewski, D. (2018). "Blue-agave fiber-reinforced polypropylene composites for automotive applications," BioRes. 13(1), 820-835.AbstractArticlePDF

    As consumer demand for more fuel-efficient vehicles increases, automakers are looking for innovative ways to reduce the weight of vehicles. Many automotive-grade plastics contain traditional reinforcing fillers, such as glass or talc, to improve the mechanical properties of the material. By replacing these high-density fillers with natural fibers, the material and corresponding weight can be reduced, which results in an improvement of the vehicle fuel economy. The objective of this study was to investigate the use of blue-agave bagasse fibers, which was sourced from tequila manufacturing waste, as a reinforcing agent in polypropylene composites. The effects of the fiber processing method, fiber loading level, and addition of a compatibilizer (polypropylene-grafted maleic anhydride) on the composite properties were determined. Samples were produced via twin-screw extrusion and injection molding. The resulting mechanical properties and morphology of the fracture surfaces were investigated. The fiber processing method (Agave C vs. Agave R) did not significantly affect the composite properties. Higher loading levels of fiber reduced both the elongation at break and impact strength, but increased the stiffness of the agave composites. The compatibilizer increased the fiber matrix adhesion, but reduced impact strength because the polymer matrix was softened.

  • Researchpp 836-845Büyüksarı, Ü., As, N., and Dündar, T. (2018). "Intra-ring properties of earlywood and latewood sections of sessile oak (Quercus petraea) wood," BioRes. 13(1), 836-845.AbstractArticlePDF

    Strength attributes of isolated microscopic sections of earlywood (EW) and latewood (LW) tissues are evaluated for sessile oak (Quercus petraea). The properties measured at the micro-scale were then used to estimate the macroscopic strength characteristics of the wood. The bending strength, modulus of elasticity (MOE) in bending, and tensile strength of EW and LW sections were determined. The EW and LW ring width, annual ring width, and LW proportion were also determined. The estimated values were calculated using the EW and LW mechanical properties and LW proportions, while the measured values were determined using standard-sized test samples. The LW sections had higher values than the EW sections for all measured mechanical properties. The average EW and LW widths and LW proportion were 0.50 mm, 0.49 mm, and 49.3%, respectively. The estimated bending strength, MOE, and tensile strength values were 80.1 MPa, 2831.7 MPa, and 112.1 MPa, respectively. The estimated bending strength and MOE values were lower than the measured values, while the estimated tensile strength values were higher than the measured values.

  • Researchpp 846-860Gogna, M., and Goacher, R. (2018). "Comparison of three Fourier transform infrared spectroscopy sampling techniques for distinction between lignocellulose samples," BioRes. 13(1), 846-860.AbstractArticlePDF

    Lignocellulosic biomass is one of the most abundant raw materials available on earth, and the study of lignocellulose components is required for the production of second-generation biofuels. Fourier transform infrared spectroscopy (FTIR) has a demonstrated potential as a cost-effective and efficient method to distinguish between lignocellulose specimens. This study compared three FTIR modes—attenuated total reflectance (ATR), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and Transmission-FTIR—in their ability to distinguish samples of different lignocellulose species at varying grain sizes, as well as before and after enzyme treatment. The reproducibility among replicates and the separation between different sample groups was assessed using an adjusted “separation/scatter” metric calculated from the scores of principal component analysis (PCA). Attenuated total reflectance was most frequently the best method due to its least amount of variance among sample replicates. However, Transmission-FTIR was better than ATR for certain particle sizes or enzyme treatments. Diffuse reflectance infrared Fourier transform spectroscopy was repeatedly inferior to ATR and Transmission-FTIR, especially in terms of variability. This work provided insight into the best mode of FTIR for characterizing lignocellulose powders. Future work should test the robustness of these results with a wider range of wood species, particle sizes, enzymes concentrations, and reaction conditions.

  • Researchpp 861-868Ayata, U., Sahin, S., Esteves, B., and Gurleyen, L. (2018). "Effect of thermal aging on colour and glossiness of UV system varnish-applied laminated parquet layers," BioRes. 13(1), 861-868.AbstractArticlePDF

    Changes are reported in perpendicular and parallel glossiness, lightness (L*), red colour (a*) tone, and yellow colour (b*) tone due to thermal aging in beech (Fagus orientalis Lipsky), maple (Acer pseudoplatanus L.), northern red oak (Quercus rubra L.), American black walnut (Juglans nigra L.), and walnut (Juglans regia L.) wood coated with a UV system commonly used on laminated parquets. Coated samples were exposed to different thermal aging levels (30 °C for 30 days, 60 °C for 60 days, and 90 °C for 90 days). Colour and gloss were determined before and after the thermal aging processes. The L* decreased for all species with the thermal aging decreasing more for more intense processes. Variations of the a* and b* colour parameters depended on the species. The colour parameters changed for temperatures higher than 30 °C. In general, glossiness decreased proportionally to the severity of the thermal aging for all of the species studied.

  • Researchpp 869-880Han, S., Seale, R. D., and Shmulsky, R. (2018). "An exploratory study of smartphone and smartphone application use in the U.S. forest products industry," BioRes. 13(1), 869-880.AbstractArticlePDF

    This work conducted market research on the use of smartphones and smartphone applications (apps) in the forest products industry and academia. Scholarly literature was reviewed, and related apps were considered. An online survey was conducted to collect data adopting a convenience sampling method. Participants were individuals who work with wood or wood-based products. The sample was compiled from publicly available online and offline sources. A questionnaire was specifically developed for this study. Out of 1,221 email invitations, 311 responses were returned at the response rate of 27.2%. Descriptive statistics and analysis of variance were used for analysis. Nearly all of the respondents (95.7%) had smartphones, and over half of them were iOS users (52.3%). A higher personal use, as compared to work use, of smartphone apps was observed. Respondents of Millennials and Generation X indicated higher personal app use than Baby Boomers. Academia and research users showed higher app uses. More respondents had purchased paid apps (45.2%) than in-app services on free apps (28.5%). This finding indicates that paid apps may be of more interest to respondents than in-app purchases.

  • Researchpp 881-893Li, R., Zhang, Z., Liu, G., Han, X., and Pu, J. (2018). "Inserting poly(ε-caprolactone) into wood cell wall structures for dehydration and consolidation of waterlogged Scots pine wood," BioRes. 13(1), 881-893.AbstractArticlePDF

    Archaeological wooden artifacts are buried in wet environments, leading to water absorption and waterlogged wood. In order to conserve these wooden cultural heritage items, dehydration and consolidation are critical steps. This study used nontoxic ε-caprolactone (CL) as the dehydration agent to replace the water in the simulated waterlogged wooden structures, inserting the poly(ε-caprolactone) (PCL) into the wood cell walls by oxalic acid catalysed CL ring-opening polymerization (ROP). The mechanical and chemical performance of the untreated and treated wood was evaluated. The weight gain percentage and dimensional stability of the treated wood were significantly improved. The polyester chains within the cell wall structures were analyzed by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA-DTA), and scanning electron microscopy (SEM). FT-IR showed that the intensity of hydroxyl (-OH) absorption peaks decreased, and carbonyl (C=O) peaks attributed to the PCL addition were observed. Thermal analysis revealed that the degradation of PCL polymers was faster than that of wood components. The morphology characterization demonstrated that the treated wood was bulked with the PCL polymers.

  • Researchpp 894-905Lan, P., Brosse, N., Cui, J. Q., Mao, H. Y., and Yang, R. (2018). "Selective biodegradation of grape pomace tannins by Aspergillus niger and application in wood adhesive," BioRes. 13(1), 894-905.AbstractArticlePDF

    The selective biodegradation of grape pomace tannins was studied using Aspergillus niger strains. The conditions were optimized in terms of monomeric catechin production. The optimal degradation conditions were: 10.0 g·L-1 of tannins in the induced medium, pH 6.5, and cultured on a shaking table at a rate of 120 r·min-1 at 28 °C for 36 h. The biodegraded tannins were used to partially substitute for phenol-formaldehyde in adhesive formulations. The biodegradation enabled the production of adhesives and wood panels with better properties (lower resin viscosity, higher internal bond strength, and lower thickness swelling). A particleboard in which the resin contained 60% biodegraded grape tannins displayed good performances (IBdry = 0.46 MPa, IBwet = 0.15 MPa) and passed the standard specifications for dry and wet conditions.

  • Researchpp 906-917Adekoya, M. A., Oluyamo, S. S., Oluwasina, O. O., and Popoola, A. I. (2018). "Structural characterization and solid state properties of thermal insulating cellulose materials of different size classifications," BioRes. 13(1), 906-917.AbstractArticlePDF

    This study investigated two classifications of wood cellulose of particle sizes 300 µm to 424 µm and 600 µm to 849 µm. The cellulose samples were characterized using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM). The cellulose crystal revealed a preferred orientation along the (200) plane for the most prominent peak. The XRD diffractogram revealed an orthorhombic structure obtained from the powder diffractogram file (PDF). Furthermore, the crystallinity index and crystalline size were calculated and the increase in crystalline size of the isolated cellulose indicated higher thermal stability. The EDX analysis showed chemical components of carbon (C), sodium (Na), chlorine (Cl), and oxygen (O) in the isolated cellulose. The morphology of the cellulose appeared as strings of fibres. The isolated cellulose has applications in the production of biomaterial, thermal insulating devices, and domestic applications.

  • Researchpp 918-928Espinosa, L., Brancheriau, L., Prieto, F., and Lasaygues, P. (2018). "Sensitivity of ultrasonic wave velocity estimation using the Christoffel equation for wood non-destructive characterization," BioRes. 13(1), 918-928.AbstractArticlePDF

    To perform a non-destructive evaluation of wood, the Christoffel equation is frequently used to describe the relationship between the ultrasonic wave velocity and the mechanical parameters. In the context of acoustical tomography imaging of standing trees, the key contribution of this numerical study is to determine the influence of mechanical parameters of the wood radial-tangential plane on the wave velocity computation using the Christoffel equation. Mechanical parameters from six species were selected. A sensitivity analysis was carried out by increasing and decreasing every parameter by a given percentage, and then by computing the variation of velocity for a set of wave direction of propagations. The evolution of the wave velocity, according to the direction of propagation, depended on the considered species; there was a difference between the softwoods and the hardwoods. The sensitivity analysis showed a bigger influence of the Young’s moduli, followed by the Poisson’s ratio, and finally by the shear modulus. However, these last two parameters cannot be neglected when using the Christoffel equation to solve the inverse problem of standing tree tomography. A proposed solution involves determining the propagation paths using the Young’s moduli as variables and then inversing the set of equations in accordance with the overall parameters.

  • Researchpp 929-944Dangvilailux, P., and Charoensuk, J. (2018). "Effects of convection and microwave drying schemes on the characteristics and sound absorption of acoustic oil palm boards," BioRes. 13(1), 929-944.AbstractArticlePDF

    This research aimed to develop economical, high-performance acoustic oil palm boards (OPB) using the convection (CV) and microwave (MW) wood drying technologies under variable thermal conditions. The results revealed that the CV and MW oven temperatures were positively correlated with moisture desorption but inversely correlated with drying time. The CV heating temperatures were inversely and positively correlated with the density and volumetric shrinkage, respectively, and the MW power output was positively correlated with density and shrinkage. Thus, the MW-treated OPB specimens exhibited stronger mechanical characteristics than the CV-treated OPB specimens. Importantly, the CV-treated OPB specimens acoustically outperformed the MW-treated counterparts, as evidenced by the former’s higher noise reduction coefficients (NRC). This phenomenon was attributed to the abundance of fissures between the vascular bundles and the parenchyma. Thus, the CV technology was more operationally and economically suited to the high-performance acoustic OPB.

  • Researchpp 945-953Salinas, C., Ananías, R., and Vasco, D. (2018). "Modelling of radio-frequency heating of piles of Pinus radiata wood," BioRes. 13(1), 945-953.AbstractArticlePDF

    The present work studied the numerical modelling of heat transfer in a pile of Pinus radiata samples of a square cross-section by using radio frequency heating.  More precisely, the study focused on the effects of the energy transferred to a dielectric material (wood) from an electromagnetic field, which required the calculation of the dielectric loss factor and its correlation with conservative equations. In this way, the temperature distribution across Pinus radiata samples was obtained through the integration of the energy equation using the finite volume method. The numerical results were compared to experimental data obtained from three experiments of radio-frequency heating of wood samples of a cross-sectional area of 4 in × 4 in, 3.1-m-long, and 20 cm of separation between plates. According to the observed linear behavior of the heat transfer process, the numerical results of the transient variation of temperature were in agreement with the experimental data.

  • Researchpp 954-966Chen, K., Jing, X., and Liao, H. (2018). "Kinetic models and effects of Mn(II) ion on ethanol production from cornstalks," BioRes. 13(1), 954-966.AbstractArticlePDF

    This paper presents a kinetic study of ethanol production by simultaneous saccharification and fermentation (SSF) from Mn(II)-catalyzed cornstalks. The optimal conditions of ethanol production were as follows: 1:2 inoculation proportion (ratio of Pachysolen tannophilus to Saccharomyces cerevisiae), 30 °C fermentation temperature, 15% inoculation quantity, 4 mg/g addition amount of Mn2+, and 10 U/g cellulase dosage. An optimal ethanol yield of 0.359 g/g was obtained from cornstalks under optimum conditions. A 38.5% increase in the yield was observed compared with the control group without the addition of Mn2+. The relationship between ethanol yield and fermentation time followed a Langmuir isotherm model. The relationship between the rate constant and fermentation time in the conversion of cornstalks to ethanol was fractal like. The findings elucidate the complex characteristics of ethanol production from cornstalks with Mn2+ catalysis and will be useful in improving production yield.

  • Researchpp 967-980Fan, F., Zheng, Z., Liu, Y., Huang, Y., and Shi, Z. (2018). "Preparation and characterisation of optimised hydrochar from hydrothermal carbonisation of macadamia shells," BioRes. 13(1), 967-980.AbstractArticlePDF

    The yield of macadamia shells (MSs) is huge. The preparation of hydrochar of MSs for the purpose of energy has broad prospects. This study investigated the possible optimum conditions for the most appropriate yield and higher heating value (HHV) of hydrochar through hydrothermal carbonisation (HTC) of MSs. The yield and HHV via HTC were systematically analysed by response surface methodology (RSM) using a synthetic weighted scoring method. The operating parameters included reaction temperature, reaction time, and water-to-biomass ratio. According to the mathematical model of RSM, the maximum response value was obtained under the following optimum conditions: reaction temperature, 220 °C; reaction time, 60 min; and water-to-biomass ratio, 11. The results showed that the reaction temperature exerted more remarkable influence than time and water-to-biomass ratio. Under the optimal conditions, the hydrochar yield and HHV were 57.58% and 22.69 MJ/kg, respectively. The results of elemental, proximate, Brunauer–Emmett–Teller, scanning electron microscopy, and Fourier transform infrared spectroscopy analyses showed that the hydrochar fuel properties improved compared with those of raw MSs. Furthermore, the surface structure and functional groups changed.

  • Researchpp 981-996Liu, M., Yang, S., Long, L., Cao, Y., and Ding, S. (2018). "Engineering a chimeric lipase-cutinase (Lip-Cut) for efficient enzymatic deinking of waste paper," BioRes. 13(1), 981-996.AbstractArticlePDF

    Lipase and cutinase belong to the esterase family and have biological applications in many fields. To develop more efficient biocatalysts that can be used for waste paper deinking, a chimeric lipase-cutinase (Lip-Cut) was constructed and successfully overexpressed in Pichia pastoris. The chimeric Lip-Cut exhibited lipase and cutinase activities that were 127% and 210% higher than their parent enzymes, respectively. Cut was superior to Lip in ink removal and improvement of paper brightness than Lip. The Lip-Cut displayed a better ink removal efficiency and paper brightness than that of the Lip, Cut, and Lip/Cut mixture. When the chimeric Lip-Cut was used, the ink removal efficiencies were 25.8% and 16.2% higher than that of the control-treated laser-printed paper and newspaper, which had sheet brightness values of 88% ISO and 59% ISO, respectively. The results demonstrated that the proper construction of bi-functional Lip-Cut could enhance the catalytic properties through the synergistic action of the two moieties because of the complementary advantages in the substrate specificities and catalysis patterns of both enzymes. This may provide an effective way to engineer more efficient bi-functional lipases and cutinases for deinking waste paper.

  • Researchpp 997-1018Yan, X., Ma, J., Wang, W., Zhao, Y., and Zhou, J. (2018). "The effect of different catalysts and process parameters on the chemical content of bio-oils from hydrothermal liquefaction of sugarcane bagasse," BioRes. 13(1), 997-1018.AbstractArticlePDF

    The effects of temperature, reaction time, biomass/water feedstock ratio, NaOH concentration, and ZSM-5 catalyst amount were investigated relative to the hydrothermal liquefaction (HTL) of sugarcane bagasse. The experimental results showed that the maximum yield of bio-oil (46.9%) was achieved with the following conditions: 10 g of sugarcane bagasse, 200 mL of distilled water, 30 min, and 285 °C. It was seen that the products of oxygenation (phenols, acids, ketones, alkenes, and esters) were abundant in the bio-oil. With the addition of NaOH, the residue yield decreased remarkably, and the yield of organics dissolved increased. The yields of acids and furfurals in the bio-oil decreased with the presence of NaOH during HTL. Additionally, ZSM-5 effectively decreased the acidic compounds and improved the liquid properties during HTL. Sugarcane bagasse in HTL with catalysts significantly improved the quality of bio-oil with lower oxygen content and higher HHV. Moreover, the gaseous products H2 and CH4 were noticeably affected by the temperature, NaOH concentration, and ZSM-5 amount.

  • Researchpp 1019-1034Jin, H., Sun, E., Xu, Y., Guo, R., Zheng, M., Huang, H., and Zhang, S. (2018). "Hydrochar derived from anaerobic solid digestates of swine manure and rice straw: A potential recyclable material," BioRes. 13(1), 1019-1034.AbstractArticlePDF

    Hydrothermal carbonization (HTC) is an efficient conversion process that treats solid digestates from anaerobic digestion plants and converts it into valuable solid products. In this study, digestates of swine manure (DS_M) and rice straw (DS_S) were HTC-treated at 190 °C with biomass-to-water ratios of 1:4 and 1:9. The hydrochars were characterized physically and chemically to elucidate their potential as a valuable resource. The hydrochars from the solid digestates were acidic, and the dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and Brunauer-Emmett-Teller surface area (SBET) were significantly (P < 0.05) higher compared with that of the feedstocks and pyrochars. Mesopores were dominant in the hydrochars, where the pores had slit-type holes and a stratified structure. The hydrochars possessed more O functional groups and aromatic C=C and C-H band than the feedstocks and pyrochars. The hydrochars derived from solid digestates were better as a solid fuel because of their combustion property. The increase in the crystallinity of the hydrochars enhanced their stability. The hydrochars produced from the DS_M were more acidic than those from the DS_S. The HTCDS_S had a better adsorptive effect on pollutants than the HTCDS_M because of the higher SBET and optimal functional groups.

  • Researchpp 1035-1041Kubojima, Y., Matsumura, Y., and Suzuki, Y. (2018). "Longitudinal vibration test for the use of a circular truncated cone as a log model of Japanese cedar," BioRes. 13(1), 1035-1041.AbstractArticlePDF

    The appropriate diameter ratio of log top and butt ends when using a round bar (cylinder shape) as a log model for estimating the density and Young’s modulus of a log was investigated. Square timbers of Japanese cedar (Cryptomeria japonica D. Don) with a length of 1200 mm were used as specimens and were machined into circular truncated cones. A longitudinal vibration test was performed to obtain the Young’s moduli of the square timbers and the circular truncated cones. The Young’s moduli were calculated using the circular truncated cone model and the round bar model. The density and Young’s modulus calculated by the circular truncated cone model were similar to those of the square timbers. Hence, it is considered that the circular truncated cone was effective for estimating the densities and Young’s moduli of logs. The density and Young’s modulus calculated by the round bar model differed from those of the square timbers when the diameters of the top ends were small. However, it is considered that the round bar can be used as a log model for actual logs.

  • Researchpp 1042-1054Badin, N., Campean, M., Lengyel, K., Ispas, M., and Bedelean, B. (2018). "Property improvement of thin high-density fiberboard panels used as door-skins," BioRes. 13(1), 1042-1054.AbstractArticlePDF

    Several potential approaches were evaluated to improve the physical and mechanical properties of 3 mm HDF panels used as door-skins. Six different composition recipes were applied by varying the ratio of hardwood-to-softwood fibers and the addition of bark. The density, surface absorption, bending strength, modulus of elasticity, and internal bond of the HDF panels manufactured on an industrial line were determined. The best performance was obtained for the recipe with 20% hardwood fibers, 80% softwood fibers, and less than 5% bark. The influence of spraying the fiber mattress before pressing, by means of water and two different release agents, was also tested. The obtained results are applicable at any HDF producer and can be used for process optimization.

  • Researchpp 1055-1064Wang, M., Li, H., Du, C., Liang, Y., and Liu, M. (2018). "Preparation and barrier properties of nanocellulose / layered double hydroxide composite film," BioRes. 13(1), 1055-1064.AbstractArticlePDF

    Cellulose nanofibrils (CNFs) were oxidized by the TEMPO oxidation system from bleached kraft eucalyptus pulp, and layered double hydroxides (LDHs) were prepared via the hydrothermal method. MgAl-CO3-LDHs/CNFs composite films with different LDH ratios were prepared via a filtering/evaporation technique that endowed the nanocomposites with barrier and strengthening properties. The MgAl-CO3-LDHs could uniformly disperse in the CNFs matrix with an improved reciprocal adhesion, and the surface result was smooth and continuous. The basic structure of the membrane did not change, but the thermodynamic properties and the water vapor barrier property improved. This composite membrane can be widely used in food, pharmaceutical, and chemical packaging industries as a gas-liquid barrier material.

  • Researchpp 1065-1074Yin, Y., Song, X., Li, C., and Nie, S. (2018). "A method for integrated optimization of chlorine dioxide delignification of bagasse pulp," BioRes. 13(1), 1065-1074.AbstractArticlePDF

    Chlorine dioxide bleaching is an important component of elemental chlorine-free bleaching. A method is introduced in this work to optimize process conditions for chlorine dioxide delignification based on nonlinear programming and response surface analysis. An energy consumption model for chlorine dioxide bleaching is established, as well as statistical models for the brightness, viscosity, and absorbable organic halogen content with the process conditions. The results from the model predict that the cost can be reduced compared to the optimization results of the response surface analysis and experiments.

  • Researchpp 1075-1087Sun, M., and Song, K. (2018). "Low temperature hydrothermal fabrication of tungsten trioxide on the surface of wood with photochromic and superhydrophobic properties," BioRes. 13(1), 1075-1087.AbstractArticlePDF

    Tungsten trioxide (WO3), which is a semiconductor, was hydrothermally synthesized onto the surface of wood. After the in-situ synthesis of WO3 nanoparticles on the wood surface, the wood exhibited photochromic and superhydrophobic properties. The WO3 nanostructures were fabricated on wood surface through a two-step hydrothermal process at 90 °C or 120 °C for 6 h. Chemical composition, crystalline structures, and morphologies of the WO3-coated wood were characterized. The results indicated that the amount of WO3 nanostructures on the surface of the wood substrate was 12.89 wt.%. Meanwhile, the WO3 nanostructures were composed of fine nanoparticles and highly crystallized by SEM and XRD analysis. When the sample was irradiated under ultraviolet (UV) light (365 nm), there was an obvious color change after 10 min (ΔE). The water contact angle measurements demonstrated that the fluorosilane modified WO3-coated wood surfaces possessed a superhydrophobic behavior with a contact angle of 152°. The sliding angle was less than 10°. Photochromic and superhydrophobic properties were achieved by a facile process, which could contribute to the development of functional wood with an aesthetic coloring.

  • Researchpp 1088-1106Zhai, R., Ma, J., Hu, Z., and Hou, J. (2018). "The effects of NaOH-Urea aqueous solution on the strength and softness properties of bamboo ligno-cellulosic fibers," BioRes. 13(1), 1088-1106.AbstractArticlePDF

    APMP (alkaline peroxide mechanical pulp) of bamboo was treated in NaOH-urea aqueous solution to modify the fiber properties. The effects of soaking time, fiber concentration, alkali dosage, freezing temperature, and freezing time were evaluated by single-factor experiments. The optimal conditions were determined as a soaking time of 10 min, a fiber concentration of 15%, an alkali dosage of 6%, a freezing temperature of -7 °C, and a freezing time of 40 min. Compared with the properties of untreated APMP, the tensile index of the treated APMP was increased by 64%, and the burst index was increased by 82%. The bulk was reduced by 15%, and the softness was increased by 18%. There was no obvious variation on the folding strength. According to the instrumental analysis, there were no significant effects on the structure in terms of functional groups, the crystalline region, or the fiber surface morphology; however, the variation on the fiber quality was more significant.

  • Researchpp 1107-1121Li, X., Li, K., Li, H., El-Mashad, H., Jenkins, B., and Yin, W. (2018). "White poplar microwave pyrolysis: Heating rate and optimization of biochar yield," BioRes. 13(1), 1107-1121.AbstractArticlePDF

    White poplar is an important biomass resource because of its high yield and fast-growing characteristics. Experiments were conducted to study the effects of microwave power, moisture content, and particle size on the heating rate and biochar yield. A Central Composite Design (CCD) was used to optimize the biochar yield. The CCD results showed that a maximum temperature-increasing rate of 2.71 °C/s was obtained with a microwave power of 2 kW and a small particle size of 100-mesh. High power, small size, and high moisture content would benefit the increase of the heating rate. An optimum biochar yield of 0.905 kg per kg poplar was obtained with a microwave power of 3 kW, moisture content of 1%, and temperature of 500 °C.

  • Researchpp 1122-1131Li, H., Zhang, H., Legere, S., Ni, Y., Qian, X., Cheng, H., Zhang, F., and Li, X. (2018). "Estimating the inter-fiber bonding capacities of high-yield pulp (HYP) fibers by analyzing the fiber surface lignin and surface charge," BioRes. 13(1), 1122-1131.AbstractArticlePDF

    Four fiber fractions from poplar alkaline peroxide mechanical pulping, performed with refiner-chemical preconditioning (P-RC APMP), were used to estimate inter-fiber bonding capacity. The relationship between fiber characteristics and inter-fiber bonding capacities was investigated. The surface lignin content of the long fiber fraction was slightly lower than that of the short fiber fraction. Atomic force microscopy (AFM) images showed that the fiber surfaces were heterogeneous (i.e., different cell wall layers were exposed along the fiber surface). The fiber fractions that had lower surface lignin content had higher bonding capacities. Furthermore, modified PFI beating was used to peel the surface of the fibers. After the peeling treatment, the fiber surface charge increased remarkably, while the surface lignin concentration decreased considerably. The lignin and charge on the fiber surface are the two key factors for estimating the inter-fiber bonding capacities.

  • Researchpp 1132-1142Sun, L., and Zhu, X. (2018). "Practical and theoretical study of the adsorption performances of straw-based tertiary amine-supported material toward sulfur dioxide in flue gas," BioRes. 13(1), 1132-1142.AbstractArticlePDF

    The primary and secondary amines of tetraethylenepentamine (TEPA) were N-methylated into tertiary amines through the Eschweiler-Clarke reaction. A straw-based tertiary amine-supported material (STA) was developed for SO2 removal, using a wet impregnation process. The effect of the adsorption conditions, such as the moisture content, flow rate, and adsorption temperature, as well as the regeneration performances were studied. Experimental results showed that STA has high SO2 adsorption capacity (approximately 100 mg/g) and can be regenerated at 100 °C. Furthermore, the adsorption of SO2 molecules on tertiary amine was studied using density functional theory (DFT). The most stable geometries of the adsorption structure in five possible positions, the geometric changes after the adsorption, and the corresponding adsorption energies were analyzed. The results showed that modified TEPA (M-TEPA) has four potential adsorbed sites (N(1,3,4,5)) with a small adsorption energy, indicating that the adsorption is weak. Moreover, the energy of the adsorbed SO2 on the N(1,3,4,5) is less than zero, indicating that the adsorption process is exothermic and spontaneous. The theoretical investigation agreed well with the experimental results.

  • Researchpp 1143-1156An, Q., Ma, H., Han, M., Si, J., and Dai, Y. (2018). "Effects of different induction media as inducers on laccase activities of Pleurotus ostreatus strains in submerged fermentation," BioRes. 13(1), 1143-1156.AbstractArticlePDF

    Sequential submerged cultivation with different induction media as inducers of ligninolytic enzyme production by Pleurotus ostreatus strains was assessed by measuring laccase activities. An unconventional material, alkali lignin, was used for the first time as an inducer for different strains to enhance laccase activity. The P. ostreatus strains secreted similar but relatively high levels of laccase activity when the induction media contained alkali lignin with or without glucose. The laccase enzyme of different P. ostreatus strains in the different media exhibited large differences, and the wild strain YAASM 0568 exhibited enhanced production of laccase compared to other cultivated strains. The laccase activities of wild strain YAASM 0568 were nearly 3.4-, 3.3-, and 5.4-fold higher than that for cultivated strains CCMSSC 00322, CCMSSC 00406, and CCMSSC 00336, respectively, when the induction media contained alkali lignin, inorganic salt, and vitamin B1. In general, induction media containing alkali lignin with or without glucose were favorable for laccase secretion. The results revealed that the type of induction material and the nature of the fungus play important roles in the expression of ligninolytic enzymes. These findings would be helpful for selection of the appropriate type of strain and for optimization of integrated industrial ligninolytic enzyme production.

  • Researchpp 1157-1173Abdul Khalil, H. P. S., Yap, S. W., Tye, Y. Y., Tahir, P. M., Rizal, S., and Nurul Fazita, M. R. (2018). "Effects of corn starch and Kappaphycus alvarezii seaweed blend concentration on the optical, mechanical, and water vapor barrier properties of composite films," BioRes. 13(1), 1157-1173.AbstractArticlePDF

    Composite films with different Kappaphycus alvarezii seaweed and corn starch concentrations were developed, and the effect of these concentrations on the films’ optical, mechanical, and water vapor barrier properties were investigated. The chemical interactions between the two components in the film were verified by chemical composition and Fourier transform infrared (FTIR) spectroscopy investigations. The results showed that the mechanical properties and opacity of the composite films were enhanced with the addition of seaweed. Among the compositions, a composite film with 3% seaweed and 1% starch exhibited the highest tensile strength and elongation at break. The water vapor permeability (WVP) of the composite films linearly increased with the increments of starch and seaweed concentrations. The FTIR analysis also revealed intermolecular interactions between the two components, consistent with the good miscibility of seaweed and starch in the blend. Therefore, different concentrations of the blend of seaweed and starch could be used to tailor a film with certain desired functional properties.

  • Researchpp 1174-1188Atiqah, A., Jawaid, M., Sapuan, S. M., and Ishak, M. R. (2018). "Effect of surface treatment on the mechanical properties of sugar palm/glass fiber-reinforced thermoplastic polyurethane hybrid composites," BioRes. 13(1), 1174-1188.AbstractPDF

    Effects of various surface modifications were evaluated relative to the mechanical properties of sugar palm fiber/glass fiber (SPF/GF) reinforced thermoplastic polyurethane (TPU) hybrid composites. The 6 wt.% alkaline, 2 wt.% silane, and combined 6 wt.% alkaline-2 wt.% silane treatment of SPF were carried out for 3 h to improve the fiber/matrix interaction of SPF/GF with TPU. The SPF and GF were fixed at 30 wt.% and 10 wt.% fiber loading, respectively, and were fabricated using the melt compounding method followed by hot compression in a moulding machine. Mechanical properties, such as tensile, flexural, and impact strength, were evaluated using a universal testing machine and an Izod impact tester. The untreated and treated hybrid composites were characterized by FTIR spectroscopy. The tensile, flexural, and impact strength of the combined 6 wt. % alkaline-2 wt. % silane treatment was improved 16%, 39%, and 18%, respectively, as compared to the untreated SPF/GF reinforced TPU hybrid composites. Moreover, the scanning electron microscopy (SEM) showed a good fiber and matrix interfacial bonding in the hybrid composites. Thus, this treated hybrid composites could be suitable for fabricating automotive parts.

  • Researchpp 1189-1201Zhang, H., Wang, Z., and Gao, H. (2018). "Preparation of 5-hydroxymethylfurfural based on the biphasic system of ionic liquid/ethyl butyrate," BioRes. 13(1), 1189-1201.AbstractPDF

    5-Hydroxymethyl furfural (5-HMF) was prepared using microcrystalline cellulose as the raw material, an ionic liquid as the solvent, and ethyl butyrate as the co-solvent. The decomposition of microcrystalline cellulose to 5-HMF in an ionic liquid/organic solvent (ethyl butyrate) biphasic system was investigated. The optimum conditions were an ionic liquid:organic solvent ratio of 1:4, reaction temperature of 130 °C, and reaction time of 3 h, which resulted in yields of 5-HMF and reducing sugar of 40.95% and 41.7%, respectively. The ionic liquid was re-utilized. The re-utilization process of the biphasic system was also studied. The solvent [BMIM]Cl could be reused twice. The primary recovery rate of [BMIM]Cl was 75.6%, and the yield of 5-HMF was 32.6%. The second recovery rate of [BMIM]Cl was 46.8%, and the yield of 5-HMF was 17.6%.

  • Reviewpp to be addedHubbe, M., Pizzi, A., Zhang, H., and Halis, R. (2018). "Critical links governing performance of self-binding and natural binders for hot-pressed reconstituted lignocellulosic board without added formaldehyde: A review," BioRes. 13(1), Pg #s to be added.AbstractPDF

    The production of fiberboard, particleboard, and related hot-pressed biomass products can convert small, relatively low-valued pieces of wood into valuable products. There is strong interest in being able to manufacture such products without the addition of formaldehyde, which is a health hazard during both production and use.  This article reviews literature describing various challenges that need to be faced in order to achieve satisfactory bonding properties in hot-pressed bio-based board products without the addition of formaldehyde.  Bonding mechanisms are examined in the form of a hypothesis, in which the strength development is represented by a chain with four links.  Failure of a board is expected to occur at the weakest of these mechanistic links, which include mechanical contact, molecular-scale wetting and contact, various chemical-based linkages, and structural integrity.  The most promising technologies for environmentally friendly production of hot-pressed board with use of lignocellulosic materials tend to be those that favor success in the development of at least three of the mechanistic links in the hypothetical chain.

  • Reviewpp to be addedCogulet, A., Blanchet, P., and Landry, V. (2018). "The multifactorial aspect of wood weathering: A review based on a holistic approach of wood degradation protected by clear coating," BioRes. 13(1), Pg #s to be added.AbstractPDF

    Wood is an abundant and renewable natural resource. Its use is promoted as a way to reduce the carbon footprint in building construction. Wood structures are degraded by their environment due to weathering. This review is a meta-analysis of the main factors of degradation that belong to this phenomenon. The impact of irradiation, the role of water, oxygen, temperature, and colonization by fungi are explained. To protect against these factors, the use of coatings is the most common solution. Since currently the trend is to maintain the grain and the natural color of the wood, the use of transparent coatings is favored. This review presents the main technologies used in clear wood coatings. The durability of this protection against weathering is approached. The whole of knowledge gathered has made it possible to begin a discussion on the multifactorial aspect of wood weathering. Schemes were created to synthesize the synergistic and antagonistic effects between the degradation factors.

     

  • Reviewpp to be addedWei, W., Li, Y., Xue, T., Tao, S., Mei, C., Zhou, W., Wang, J., and Wang, T. (2018). "The research progress of machining mechanisms in milling wood-based materials," BioRes. 13(1), Page numbers to be added.AbstractPDF

    The machining mechanisms in milling for medium-density fiberboard (MDF) and wood-plastic composites (WPC) are reviewed in this article. The study focuses on milling tool wear, chip formation mechanisms, processing stability, and machined surface roughness. The influence law of cutting parameters (cutting speed, feed rate, and cutting thickness), tool materials and geometry (rake angle, relief angle, and size parameters), temperature, and other factors on tool wear and machined surface roughness were considered. Concrete measures to improve tool life and machined surface quality are summarized as well as an online monitoring system of tool wear and machined surface roughness. Future research of tool wear and surface quality in milling wood-based materials is proposed to provide important references for wood-based materials researchers.

  • Reviewpp to be addedXu, Y., Li, S., Yue, X., and Lu, W. (2018). "Review of silver nanoparticles (AgNPs)-cellulose antibacterial composites," BioRes. 13(1), Page numbers to be added.AbstractPDF

    With the improvement of living standards, the human demand for antibacterial materials has increased. Cellulose, as the most abundant polymer in the world, is natural, biodegradable, and renewable, which makes it a promising raw material for the production of antibacterial materials. Silver nanoparticles (AgNPs)-cellulose antibacterial composites exhibit good biocompatibility and antimicrobial properties. These materials are easily degraded chemically and are environmentally friendly. Therefore, the AgNPs-cellulose antibacterial composites exhibit broad utilization prospects in environmental protection, medicine, chemical catalysis, and other fields. Several methods are used to manufacture such materials. This paper reviews three common techniques: the physical method, the in situ chemical reduction method, and the covalent bonding method. The differences and relationships are identified, and the advantages and disadvantages are compared among these three methods. Lastly, the present situation and the development potential of the AgNPs-cellulose antibacterial composites are discussed in this review.

  • Researchpp 1202-1222Frodeson, S., Henriksson, G., and Berghel, J. (2018). "Pelletizing pure biomass substances to investigate the mechanical properties and bonding mechanisms," BioRes. 13(1), 1202-1222.AbstractPDF

    Solid fuel for heating is an important product, and for sustainability reasons, it is important to replace nonrenewable fuels with renewable resources. This entails that the raw material base for pellet production has to increase. A broader spectrum of materials for pelleting involves variation in biomass substances. This variation, due to lack of knowledge, limits the possibilities to increase the pellet production using new raw materials. In this study, pellets were produced with a single pellet press from 16 different pure biomass substances representing cellulose, hemicellulose, other polysaccharides, protein, lignin, and extractives, and five different wood species, representing softwoods and hardwoods. All pellets were analyzed for the work required for compression and friction, maximum force needed to overcome the backpressure, pellet hardness, solid density, and moisture uptake. The results showed that the hardest pellets were produced from the group of celluloses, followed by rice xylan and larch arbinogalactan. The weakest pellets were from the group of mannans. Conclusions are that the flexible polysaccharides have a greater impact on the pelletizing process than previously known, and that the differences between xylan and glucomannan may explain the difference in the behavior of pelletizing softwoods and hardwoods.

  • Researchpp 1223-1234Ma, C., Mei, X., Fan, Y., and Zhang, Z. (2018). "Oxidative depolymerizaton of kraft lignin and its application in the synthesis of lignin-phenol-formaldehyde resin," BioRes. 13(1), 1223-1234.AbstractPDF

    Kraft lignin (KL) was valorized by introducing phenolic hydroxyl groups and adjusting the molecular weight by oxidative depolymerization. Hydrogen peroxide with copper sulfate as a catalyst was employed in this process. The depolymerized lignin (DL) was characterized with differential ultraviolet spectrum (UV), Fourier transform infrared (FT-IR) spectrometry, gel permeation chromatography (GPC), and heteronuclear single quantum correlation (HSQC) spectra. Both the molecular weight (Mw and Mn) and the polydispersity of the depolymerized lignin decreased compared with default kraft lignin. The content of phenolic hydroxyl groups increased from 1.55 to 2.66 mmol/g. The depolymerized lignin was used in the synthesis of lignin-phenol-formaldehyde (LPF) resin as a substitution of phenol. The physical properties including viscosity, bonding strength, and free formaldehyde content of the adhesive met the GB/T 14704-2006 standard with the substitution of 50% phenol with DL.

  • Researchpp 1235-1250Pam, A. A., Abdullah, A. H., Tan, Y. P., and Zainal, Z. (2018). "Batch and fixed bed adsorption of Pb(II) from aqueous solution using EDTA modified activated carbon derived from palm kernel shell," BioRes. 13(1), 1235-1250.AbstractPDF

    Activated carbons were synthesized by thermochemical treatment of palm kernel shells (AC-PKS) and modified with ethylenediaminetetraacetic acid (AC-EDTA). The developed products were characterized by the surface area, porosity, and pH of point zero charge and were used for removal of Pb(II) ions from aqueous solution. The AC-PKS exhibited higher BET surface area (1559.9 m2/g) than the AC-EDTA (1100.7 m2/g). The influence of solution pH, adsorbent dose, initial Pb(II) ion concentration, and temperature on the removal of Pb(II) ions were examined and optimized. The adsorption of Pb(II) on AC-PKS and AC-EDTA fitted the pseudo-second-order kinetics model and the Langmuir model isotherm, respectively. The optimum conditions for sorption of Pb(II) were at the initial Pb(II) concentration of 150 mg/L, dosage 0.35 g (AC-PKS) and 0.25 g (AC-EDTA), and pH 4. Thermodynamic studies showed that the adsorption process was spontaneous and endothermic. The AC-PKS and AC-EDTA both demonstrated high Qmax of 80.6 mg/g and 104 mg/g, respectively, for Pb(II) adsorption. The adsorption data also fitted the Thomas fixed-bed adsorption model.

  • Researchpp 1251-1264Kaplan, L., Kvietková, M., and Sedlecký, M. (2018). "Effect of the interaction between thermal modification temperature and cutting parameters on the quality of oak wood," BioRes. 13(1), 1251-1264.AbstractPDF

    Selected parameters and their effects were analyzed relative to the surface quality of thermally modified oak wood (Quercus cerris), which was evaluated using the mean arithmetic deviation of the roughness profile (Ra) during planar milling. Each measurement was taken at various parameters of the milling process, such as cutting speed, feed rate, tool geometry, and thermal treatment of the material. The measured results were compared with results measured on thermally untreated specimens (20 °C). The total amount of material removal was 1 mm. These characteristics were measured using a contact profilometer. Based on the results, thermal modification did not have a statistically significant effect on the roughness. The feed rate, rake angle, and cutting speed had the most significant effects on the monitored characteristic. The lowest average roughness values were found with a rake angle of 25°, feed rate of 4 m/min, and cutting speed of 40 m/s. Increasing the cutting speed led to a reduction in the average roughness, while increasing the feed rate had the opposite effect.

  • Researchpp 1265-1277Ding, Z., Tong, L., Li, H., Lu, W., Zhang, W., and Bu, X. (2018). "Quantitative prediction of agarotetrol in Chinese eaglewood using near infrared spectroscopy," BioRes. 13(1), 1265-1277.AbstractPDF

    To overcome the numerous disadvantages of existing testing technology, a novel, fast, nondestructive, and quantitative technology for quality evaluation of Chinese eaglewood (CE) based on near-infrared (NIR) technology was proposed in this study. The extractives of CE were qualitatively analyzed to determine the types of volatile compounds using gas chromatography-mass spectroscopy and were quantitatively determined using high performance liquid chromatography (HPLC). Agarotetrol was quantitatively determined by the HPLC analysis. The content was found to range widely from 0.016 to 0.104 mg/g. A quantitative prediction model aimed at quality control was proposed based on the qualitative and quantitative results coupled with a partial least squares regression. The coefficient of correlation and residual predictive deviation of the prediction model were determined to be 0.9697 and 5.77, respectively. The practical tests showed an average error of 0.000327%, which indicated that the method was able to provide a novel, quick, and effective quality evaluation of CE.

  • Researchpp 1278-1288Li, Z., Liu, Y., and Wu, S. (2018). "Efficient conversion of D-glucose into D-sorbitol over carbonized cassava dregs-supported ruthenium nanoparticles catalyst," BioRes. 13(1), 1278-1288.AbstractPDF

    A carbonized cassava dregs-supported ruthenium nanoparticles catalyst (Ru/CCD) was prepared by a simple impregnation-chemical reduction method. The synthesized Ru/CCD catalysts were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The catalytic performances of the Ru/CCD catalysts were evaluated in the conversion of D-glucose into D-sorbitol under hydrogen atmosphere. Moreover, the effects of various parameters on glucose hydrogenation and the recyclability of the catalysts were investigated in detail. The optimized D-sorbitol yield reached up to 98.6% at 120 °C for 1.5 h with D-glucose conversion of 99.7%. The Ru nanoparticles played an important role in the hydrogenation of D-glucose into D-sorbitol, and the Ru particle was widely dispersed all over the support surface. In addition, the Ru/CCD catalyst was stable during the reaction and was reused for up to five successive runs with a slight decrease in D-sorbitol yield.

  • Researchpp 1289-1302Lengyel, K., Barbu, M., Campean, M., Badin, N., and Bogdan, B. (2018). "Improving properties of particleboards with reduced density," BioRes. 13(1), 1289-1302.AbstractPDF

    The goal of this research was to examine factors affecting the feasibility of manufacturing particleboards at significantly lower density, while reducing the formaldehyde emissions. A further goal was to not significantly affect other important physical and mechanical properties of the boards, including swelling in thickness, surface absorption, bending strength, modulus of elasticity, internal bond, and surface soundness. By varying the raw material recipe (ratio between hardwood and softwood chips), it was found that increasing the amount of hardwood chips led to a significant decrease of the formaldehyde emissions, but also to a significant increase of the thickness swelling and surface absorption. The simple density reduction of particleboards was not a viable alternative because all properties were seriously affected. Therefore, the tests on particleboards with reduced density were repeated, but this time an isocyanate-based additive was added into the recipe at 0.25% and 0.4%. A noticeable improvement of all analyzed properties was achieved.

  • Researchpp 1303-1328Rivero-Be, O., Peraza-Góngora, J., Cupul-Manzano, C., Carrillo-Baeza, J., Guillén-Mallette, J., Rivero-Ayala, M., Valadez-González, A., and Cruz-Estrada, R. (2018). "Preparation of pinewood residues/recycled HDPE composites with potential to substitute medium-density fiberboards," BioRes. 13(1), 1303-1328.AbstractPDF

    This work reports on the preparation of pinewood residues/recycled high-density polyethylene (HDPE) composites to evaluate their performance under flexion, extraction of nails and screws, and moisture absorption (MA) to assess their potential to replace medium-density fiberboards (MDFs). The effect of filler particle size (PS) was evaluated, and scanning electron microscopy (SEM) was conducted to elucidate the state of the interphase. The effect of UV-light accelerated weathering (AW) on samples with and without a UV stabilizer (UVS) was assessed. A dynamic mechanical analysis (DMA) was also conducted. The composites had better flexural performance, MA, and screw extraction resistance than the MDFs. However, AW affected the composites, mostly affecting those without UVS. Scanning electron microscopy showed the appearance of cracks on the surfaces with less UVS. The DMA results suggested that the composites with the largest PS showed a better resistance to creep.

  • Researchpp 1329-1347Zhu, X., Xue, Y., Zhang, S., Zhang, J., Shen, J., Yi, S., and Gao, Y. (2018). "Mechanics and crystallinity/thermogravimetric investigation into the influence of the welding time and CuCl2 on wood dowel welding," BioRes. 13(1), 1329-1347.AbstractPDF

    Mechanical properties of wood dowel welding were studied using untreated and copper chloride (CuCl2)-treated wood dowels. The effect of the welding time (3 s, 5 s, and 7 s) was also studied. The treated wood dowels with a welding time of 3 s had the best pullout resistance. Fibers covered with black molten material generated by the high friction temperature were found at the welding interfaces. For the untreated groups, the degree of crystallinity of the welding interfaces was higher than that of the wood dowel. For the treated groups, the degrees of crystallinity for the welding times of 5 s and 7 s were lower than that of the wood dowel. By extending the welding time, the degree of crystallinity decreased. A thermogravimetric (TG) analysis was used to detect changes in the wood components. The hydrolysis of cellulose and hemicellulose occurred during immersion. The analyses illustrated that pyrogenic decomposition of the wood components occurred during the wood dowel welding process. For the treated groups, the degree of pyrolysis was higher than that of the untreated groups for the same welding time. An increased welding time also promoted pyrolysis during the welding process.

  • Researchpp 1348-1359Wu, T., Fang, G., Liang, L., Deng, Y., Lin, Y., and Xiong, Z. (2018). "Analysis of mixed pulping raw materials of Eucalyptus globulus and Acacia mangium by near infrared spectroscopy technique combined with LASSO algorithm," BioRes. 13(1), 1348-1359.AbstractPDF

    To meet the current demand in China for Eucalyptus globulus and Acacia mangium mixed pulping, a study was conducted to collect the near infrared (NIR) spectra of 150 mixed samples of E. globulus and A. mangium in which the content of E. globulus was manually controlled. After the original spectra were pretreated by first derivative and standard normal variate (SNV), the least absolute shrinkage and selection operator (LASSO) algorithm and cross-validation were used to calculate the optimal adjustment parameters of 14.30, 19.16, 12.10, and 9.74, respectively. The optimal calibration models for the content of E. globulus, holocellulose, pentosan, and acid insoluble lignin were generated. An independent verification of the calibration models showed that the root mean square error of prediction (RMSEP) for these models was 1.59%, 0.54%, 0.66%, and 0.40%, respectively. The absolute deviation (AD) was -2.58% to 2.73%, -0.91% to 0.84%, -1.19% to 1.06%, and -0.61% to 0.64%, respectively. The prediction performance of the four models was sufficient for real-time analysis in the pulping production line. The LASSO algorithm was judged to be efficient for the prediction and analysis of mixed raw materials in pulping industry.

  • Researchpp 1360-1371Konopka, A., Barański, J., Orłowski, K., and Szymanowski, K. (2018). "The effect of full-cell impregnation of pine wood (Pinus sylvestris L.) on changes in electrical resistance and on the accuracy of moisture content measurement using resistance meters," BioRes. 13(1), 1360-1371.AbstractPDF

    The impact of the full-cell impregnation of pine wood was investigated with respect to changes in electrical resistance and the accuracy of moisture content measurement. This study compared the resistance of impregnated and untreated pine timber harvested from the northern part of Poland (Pomeranian region). The wood was impregnated by the vacuum-pressure method. The preservative (TANALITH E 3475) and coloring (TANATONE 3950) agents were based on copper salts. The results showed a dependence of wood resistance as a function of the moisture content. Impregnated and not treated wood samples were used. This result reflects the greater conductivity of the impregnate solution (based on copper salt) than the water. This phenomenon became more distinctive as moisture content value was above the Fiber Saturation Point (FSP).

  • Researchpp 1372-1387Przybysz, K., Małachowska, E., Martyniak, D., Boruszewski, P., Iłowska, J., Kalinowska, H., and Przybysz, P. (2018). "Yield of pulp, dimensional properties of fibers, and properties of paper produced from fast growing trees and grasses," BioRes. 13(1), 1372-1387.AbstractPDF

    Paper is produced mainly from wood fibrous pulps, which has been increasingly replaced by pulps from fast growing plants due to limited wood resources. In this work, properties of cellulosic pulps produced by the sulfate method from four fast growing grasses, poplar cultivar ‘Hybrid 275’, and European larch, as well as pine and birch wood chips, were compared. In addition, the cellulosic pulp yield, dimensions of fibers contained in the pulps and mechanical and optical characteristics of paper sheets produced from the pulps were compared. The pulp yield of the poplar cultivar ‘Hybrid 275’ (51.6%) was almost 5% higher than birch pulp (47.0%). Moreover, all of the investigated tensile properties of paper made from ‘Hybrid 275’ pulp were higher than for paper produced from birch pulp. Fast growing grasses, despite lower pulp yield (34.0 to 47.1%), showed comparable tensile properties to birch. Therefore, these pulps are promising raw materials for papermaking.

  • Researchpp 1388-1400Liang, J., Zhang, J., Du, G., Feng, S., Xi, X., and Lei, H. (2018). "Lignin-based grinding wheels with aluminum oxide: Synthesis and characterization," BioRes. 13(1), 1388-1400.AbstractPDF

    By using renewable inexpensive plant-derived materials such as lignin and furfuryl alcohol, a new bio-based, easily-prepared, and industrially suitable thermosetting grinding wheel named lignin-furanic grinding wheel (LFG) was prepared and characterized. Cross-linking between lignin and furfuryl alcohol under acidic conditions was established by carbon-13 nuclear magnetic resonance (13C-NMR) and electrospray ionization mass spectrometry (ESI-MS). In addition, as the results of thermomechanical analysis (TMA) and thermogravimetric analysis (TGA) suggested, the lignin-furanic resin exhibited high resistance to heat, and the glass transition temperature (Tg) as high as 170 °C. The new lignin-based grinding wheel presented no pores or cracks in the surface and it had a high hardness and compression resistance compared to the commercial phenolic grinding wheel (PG). Moreover, it exhibited high abrasiveness, and the cutting time for a metal tube was shorter than that of PG.

  • Researchpp 1401-1412Niu, X., Pang, J., Cai, H., Li, S., Le, L., and Wu, J. (2018). "Process optimization of large-size bamboo bundle laminated veneer lumber (BLVL) by Box-Behnken Design," BioRes. 13(1), 1401-1412.AbstractPDF

    This work focuses on optimization of the laminated lap-joint lengthening technology that is used to produce large-size bamboo bundle laminated veneer lumber (BLVL). A three-factor Box-Behnken design was developed in which lap-joint length (x1), board density (x2), and thickness of lap veneer (x3) were the three factors. Multi-objective optimization of response surface model was used to obtain 17 optimum Pareto solutions by a genetic algorithms method. The mechanical properties of BLVL predicted using the model had a strong correlation with the experimental values (R2 = 0.925 for the elastic modulus (MOE), R2 = 0.972 for the modulus of rupture (MOR), R2 = 0.973 for the shearing strength (SS)). The interaction of the x1 and x3 factors had a significant effect on MOE. The MOR and shearing SS were significantly influenced by the interaction of x2 and x3 factors. The optimum conditions for maximizing the mechanical properties of BLVL lap-joint lengthening process were established at x1 = 16.10 mm, x2 = 1.01 g/cm3, and x3 = 7.00 mm. A large-size of BLVL with a length of 14.1 m was produced with the above conditions. Strong mechanical properties and dimensional stability were observed.

  • Researchpp 1413-1424Pérez-Pena, N., Chávez, C., Salinas, C., and Ananías, R. (2018). "Simulation of drying stresses in Eucalyptus nitens wood," BioRes. 13(1), 1413-1424.AbstractPDF

    The objective of this work was to simulate the stresses produced during the drying of Eucalyptus nitens wood due to variations in the moisture content. The methodology involved experimental determination and simulation of drying stresses caused by the development of internal moisture content gradients. Modeling of the moisture transport was based on the concept of an effective diffusion coefficient. The mathematical model for stress-strain, and for moisture diffusion into the wood, was constituted by a system of second-order nonlinear partial differential equations with variable coefficients, which were numerically integrated by the control volume based on the finite element method (CVFEM). For validation purposes, tests were realized for evaluating deformations, stress drying, and moisture gradients that were produced during the drying of Eucalyptus nitens. The results showed satisfactory agreement between the experimental and simulated values, indicating an effective simulation.

  • Researchpp 1425-1440Li, W., Zhang, T., and Pei, G. (2018). "Catalytic conversion of corn stover into furfural over carbon-based solid acids," BioRes. 13(1), 1425-1440.AbstractPDF

    To ascertain the applicability of the isoamyl nitrite-assisted sulfanilic acid sulfonation method, a series of carbon precursors (sucrose-derived disordered mesoporous carbon, ordered mesoporous carbon CMK-3, glucose-based hydrothermal carbon, and activated carbon) were utilized in attempts to synthesize carbon-based solid acids. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, elemental analysis (EA), and temperature-programmed desorption of ammonia (NH3-TPD) were applied to characterize the catalysts. The carbon-based solid acids were applied in the dehydration of xylose and corn stover to evaluate their catalytic performance. Sucrose-derived disordered mesoporous carbon (C-CCA) and ordered mesoporous carbon CMK-3 were successfully sulfonated by isoamyl nitrite-assisted sulfonation, while glucose-based hydrothermal carbon (HGC) and activated carbon (AC) were unsuccessful. Compared with ordered mesoporous carbon CMK-3 solid acid (S-CMK-3), sucrose-derived disordered mesoporous carbon solid acid (ISC-CCA) showed better performance for the production of furfural. The reusability of ISC-CCA for furfural production from xylose during 5 runs was favorable. Using pure water and ISC-CCA as a solvent and catalyst, from corn stover, achieved a furfural yield of 43.1% at 190 °C in 4 h.

  • Researchpp 1441-1456Mou, H., Wu, S., He, M., Liu, H., Huang, H., and Xu, C. (2018). "Study of the difference between enzyme adsorption onto hydrotropic and alkali lignin separated from eucalyptus and bamboo," BioRes. 13(1), 1441-1456.AbstractPDF

    Enzymatic hydrolysis of lignocellulosic biomass is the key step for controlling the cost of bioethanol production. However, the non-productive adsorption of cellulase onto lignin in biomass severely hampers the enzyme activity and hydrolysis efficiency. Thus, understanding the adsorption mechanism of cellulase onto lignin is critical for the development of enzyme mixtures and enzymatic hydrolysis. In this investigation, cellulase, β-glucosidase (BG), and xylanase adsorption onto lignin from eucalyptus and bamboo, extracted by alkali and hydrotropic techniques, were compared. The physico-chemical properties of the four types of isolated lignin were detected. Langmuir isotherms were used to interpret the cellulase adsorption kinetics of the lignin. The hydrophobicity was found to be the major factor that affected the cellulase adsorption affinity of lignin. The surface charge was important for the adsorption of BG and xylanase onto the lignin. A comparison was made between hydrotropic and alkali lignin, and the hydrotropic lignin from eucalyptus had the highest cellulase adsorption capacity and lowest BG and xylanase adsorption capacities.

  • Researchpp 1457-1474Kuokkanen, M., Mäentausta, O., and Kuokkanen, T. (2018). "Eco- and material-efficient utilization applications of biotechnologically modified fiber sludge," BioRes. 13(1), 1457-1474.AbstractPDF

    Wood fiber sludge is a by-product of the pulp and paper industry, and 750,000 tons are generated per year in Finland. When aqueous fiber sludge (solid matter content 10 to 20%) is modified with water and enzymes, it is called biotechnologically modified fiber sludge (BMFS). So far, native fiber sludge has been only a waste material in Finland, but according to a new waste law, its waste tax is 70 € per ton. According to the present EU and Finnish strategies on waste materials, circular economy, and material-efficiency, all waste must be utilized primarily as material (reuse, recycling) and secondarily as energy. For these reasons, it is very important to develop new eco-, cost- and material-efficient utilization methods for this aqueous “pure waste” instead of landfilling and combustion. Continuing earlier experiments, which proved that BMFS is a good and efficient binding agent for combustion pellets, BMFS was studied in new utilization applications such as bedding pellets for horses as well as a road and horse riding hall dust binding agent. In laboratory measurements and field experiments, BMFS is a very efficient dust-binding agent and effective binding agent for bedding pellets.

  • Researchpp 1475-1490Lin, M., Xia, K., Lu, P., Ou, Y., Su, L., and Liu, D. (2018). "Smart hydrophobic-hydrophilic self-switching cellulosic materials synthesized by regioselective functionalization," BioRes. 13(1), 1475-1490.AbstractPDF

    Smart hydrophobic-hydrophilic self-switching cellulosic materials were synthesized by regioselective functionalization of cellulose in green Ionic Liquids (ILs). The thermal analysis indicated that the introduction of a macromolecular structure including a trityl or heptafluorobutyric group onto the cellulose chain increased the thermal stability of the cellulose derivatives. Wetting contact angle of the surface decreased from 103° to 73° as the holding time increased at ambient conditions (19.8 °C, 65%). After wetting, the surface free energy increased from 11.03 to 34.09 J·m, of which the polarity component increased from 60.92% to 94.19%. The XPS analysis indicated that the content of oleophobic-hydrophobic CF3-CF2-CF2-CO- groups at the exposed surface decreased after wetting, while the hydrophilic HOOC- groups increased, which verified the self-switching process between the hydrophobic and hydrophilic properties within the cellulosic materials. The self-switching characteristic means that the biodegradable cellulosic materials have suitable selectivities for high-impact applications in various fields.

  • Researchpp 1491-1509Terzi, E., Kartal, S., Pişkin, S., Stark, N., Kantürk Figen, A., and White, R. (2018). "Colemanite: A fire retardant candidate for wood plastic composites," BioRes. 13(1), 1491-1509.AbstractPDF

    The use of raw boron minerals (i.e. tincalconite, colemanite, and ulexite) was evaluated to increase the fire performance of wood plastic composites (WPCs) in comparison with commercially available fire retardants (FRs). Cone calorimetry and limited oxygen index tests were performed to evaluate the fire properties of WPC specimens. Artificial weathering and 3-point bending tests were also performed on the test specimens loaded with the highest loading level of FRs. The most important decrease in the heat release rate values was 42% and 40% in the magnesium hydroxide- and colemanite-added WPCs at a loading level of 15% (w/w), respectively. Incorporation of colemanite and ulexite into the WPCs increased the limited oxygen index levels by nearly 13% at the same loading level. An increase was observed in the peak heat release rate values in all of the WPC specimens after accelerated weathering. All of the FRs had statistically improved MOE values compared with the control WPC specimens. In particular, the incorporation of zinc borate and borax increased the MOE values by approximately 48% and 42%, respectively. Similar to the effect on the MOE values, zinc borate and borax improved the modulus of rupture the most (approximately 18%).

  • Researchpp 1510-1524Xue, W., Lei, F., Li, P., and Jiang, J. (2018). "Cellulose accessibility and zeta potentials of sugarcane bagasse pretreated by green liquor and ethanol for high hydrolysis efficiency," BioRes. 13(1), 1510-1524.AbstractPDF

    Green liquor (GL) combined with ethanol (GL-ethanol) was selected to pretreat sugarcane bagasse (SCB). The results showed that the maximum lignin removal of 85.2% was achieved at 160 °C and a GL loading of 1.5 mL/g-dry substrate. The glucose yield of pretreated SCB increased with increased pretreatment temperature, and the maximum glucose yield of 97.7% was reached from SCB pretreated at 160 °C. Simons’ stain (SS) showed that the glucose yield was affected by cellulose accessibility instead of lignin content when lignin removal was > 70%. The cellulase adsorption isotherm fitted by the Langmuir model showed that the strength of interaction between the cellulase and substrate of GL-ethanol-100/1.5 (100 °C, 1.5 mL GL/g-dry substrate) was declining with increased pH. The adsorption was pH-dependent, and negatively controlled by the pH value. Electrostatic interactions can account for the pH-dependency of cellulase adsorption.

  • Researchpp 1525-1533Dzurenda, L. (2018). "The shades of color of Quercus robur L. wood obtained through the processes of thermal treatment with saturated water vapor," BioRes. 13(1), 1525-1533.AbstractPDF

    This paper presents the shades of color of Quercus robur L. wood obtained in the processes of thermal treatment and color modification by saturated water vapor, with temperatures: tI = 112.5 ± 2.5 °C for t = 5.5 h (mode I), tII = 127.5 ± 2.5 °C for t = 6.5 h (mode II), and tIII = 137.5 ± 2.5 °C for t = 7.5 h (mode III).  The color of oak wood by thermal treatment in mode I changes minimally with mild browning in the CIE-L*a*b* color space: L* = 65.5 ± 1.7; a* = 8.8 ± 0.4; b* = 20.7 ± 0.5. A brown shade with coordinates: L* = 56.8 ± 1.3; a* = 9.3 ± 0.5; b* = 19.4 ± 0.5 is achieved in mode II. Oak wood thermally modified by mode III acquires an original brown-gray color with the color coordinates: L* = 47.5 ± 2.1; a* = 9.4 ± 0.5; b* = 17.1 ± 1.1. The irreversible changes in the color of the oak wood, achieved by some of the color modifications of wood using saturated water steam, extend the possibilities of its use in the field of building-joinery, the artistic field, and the field of design.

  • Researchpp 1534-1547Sadaka, S., and Atungulu, G. (2018). "Grain sorghum drying kinetics under isothermal conditions using thermogravimetric analyzer," BioRes. 13(1), 1534-1547.AbstractPDF

    This research aimed to determine the isothermal drying kinetic parameters of grain sorghum using a thermogravimetric analyzer (TGA). The kernels were placed in the TGA under isothermal drying conditions, i.e., 40, 50, 60, 70, 80, 90, and 100 °C. Changes in the sample weight were determined from the TGA and the data were used to determine the moisture ratio and the derivative of the weight loss curves. The moisture ratio data obtained experimentally were fitted to four well-known models, namely Page, Newton, Logarithmic, and Henderson, to determine the best-fit model for the experimental data. The goodness of fit criteria was used to determine the best-fit model. An increased drying temperature from 40 °C to 100 °C accelerated the drying process and decreased the moisture ratio from 0.6091 to 0.2909, after 1 h. The Page model was the best fit for 71.4% of the drying curves, whereas the Logarithmic and Henderson models were the best fit for 28.6% of the studied cases. Increasing the drying temperature from 40 °C to 100 °C increased the effective moisture diffusivity from 0.96 × 10−8 m2/s to 1.73 × 10−8 m2/s. The drying activation energy value reached 9.4 kJ/mol under isothermal drying conditions.

  • Reviewpp to be addedYang, L., and Liu, H. (2018). "A review of Eucalyptus wood collapse and its control during drying," BioRes. 13(1), Page #s to be added.AbstractPDF

    The relevant literature is reviewed concerning eucalyptus wood collapse, with a focus on lumber drying technology. Potential future research is summarized regarding where potential future work may focus. Eucalyptus is often limited as a solid wood products material due to microstructural collapse and interior cracking that may occur during drying. To prevent the drying collapse, studies have focused on the mechanism of collapse, the morphological characteristics of collapse, the control of collapse, amongst other criteria. Because the surface tension of water results in wood cell collapse, the shape of collapsed cells should be recovered after the liquid tension disappears. Therefore, pretreating green timber (such as pre-heating, pre-steaming, microwave treatment, pre-freezing, or boiling) prior to drying results in the modification of wood cell tissue and inhibits the conditions for collapse. Thus, there is improved wood permeability, drying rate, shortened drying time, as well as reduced collapse during the drying process. In addition, applying process control in regards to a suitable drying schedule (especially the drying temperature), relative humidity, drying time, intermittent drying process, combined drying technology, etc., tends to reduce the amount of collapse and improve drying quality. Reconditioning, such as steaming during the drying process, can aid collapse recovery. Generally, reconditioning or other treatment can help recover 50% of the collapse.

  • Researchpp 1548-1562Zhao, G., Qiu, Z., Shen, J., Deng, Z., Gong, J., and Liu, D. (2018). "Internal structural imaging of cultural wooden relics based on three-dimensional computed tomography," BioRes. 13(1), 1548-1562.AbstractPDF

    An efficient method for the internal structural imaging of cultural wooden relics was explored through experimental techniques of three-dimensional (3-D) tomography and reconstruction. The techniques of filtering and segmentation were applied to the 3-D scanned data of wooden cultural relics.To obtain high resolution 3D data model, it was necessary to preprocess the raw data after CT scanning. Preprocessing included denoising, filtering, and segmentation. After completing these three steps, three-dimensional reconstruction experiments were carried out (including surface rendering and volume rendering). After the 3-D reconstruction, the wood internal properties were visually analyzed and used to create internal structural imaging of wooden artifacts. On the basis of volume rendering, wooden artifacts could be graphically divided at any angle and any position. The textures of local wooden relics were clearly revealed in the segmentation of the reconstruction pictures, and these were compared with the presented internal structural image testing of the wooden artifacts. This study showed that the proposed technology can successfully create internal structural images of wooden artifacts, as well as provide important data and models to support the renovation and recovery of the cultural wooden relics.

  • Researchpp 1563-1575Liu, R., Morrell, J. J., and Yan, L. (2018). "Thermogravimetric analysis studies of thermally-treated glycerol impregnated poplar wood," BioRes. 13(1), 1563-1575.AbstractPDF

    The effects of glycerol pretreatment and thermal modification on poplar wood was examined using thermogravimetric analysis (TGA). The total mass losses of thermally-treated samples before and after glycerol impregnation were studied. The thermal degradation process was divided into three stages based on natural breaks in the slope of the TGA curves. The set-on and set-off temperatures, mass loss, and activation energy (Ea) of each stage were compared. Pretreatment with 60% glycerol followed by thermal modification at 160 °C produced pronounced differences in the three decomposition stages. Fewer wood components were decomposed in the first stage in glycerol-pretreated wood, which suggested that the pretreatment had modified the wood components into more thermally stable substances. However, the mass losses were higher in the next stage, suggesting that the effect on thermal stability was limited. The Ea values of wood decomposition during the first stage were decreased, while those during the second and third stages were increased. These results illustrate the potential for using a glycerol pretreatment to alter the thermal stability of wood.

  • Researchpp 1576-1590Pertuzzatti, A., Missio, A. L., Cademartori, P. H. G., Santini, E. J., Haselein, C. R., Berger, C., Gatto, D. A., and Tondi, G. (2018). "Effect of process parameters in the thermomechanical densification of Pinus elliottii and Eucalyptus grandis fast-growing wood," BioRes. 13(1), 1576-1590.AbstractPDF

    Densification parameters were investigated for the fast-growing pine and eucalyptus. Both woods showed optimal results in terms of apparent density and mechanical properties when milder treatments of 150 °C were applied. Pine showed mass loss and improved mechanical properties with a longer heating time of 60 min, while eucalypt performed better with shorter treatments of 30 min. Eucalypt has more highly acetylated hemicelluloses, mainly composed of xylose units, which degrade more quickly with consequent decrease in mass and mechanical properties. However, apparent densities close to 1.0 g·cm-3 were obtained, and greatly enhanced bending properties, hardness, and impact resistance were observed, especially when the optimal parameters were used. Treatments at 170 °C or greater, while resulting in well-densified specimens, yielded inferior mechanical properties. The densified woods also presented initial apparent contact angles greater than 85°, highlighting a considerable increase of hydrophobicity. The densification process therefore allows these less valuable timber species to be used in applications such as flooring and decking.