NC State
  • Editorialpp 1-2Hubbe, M. A., and Lucia, L. A. (2016)."BioResources: Ten years of service for the progress of the science and technology of lignocellulosic products," BioRes. 11(1), 1-2.AbstractPDF
    The co-editors of BioResources note the completion of our first ten years. We think that the journal can be judged as a success based on having achieved an impact factor of about 1.4 each year since 2009 and having reached a publication rate of about 700 articles per year. We strive to be a “people’s journal” serving scientists, students, and society. We plan to continue emphasizing editorial pieces and review articles, which supplement our main service of publishing peer-reviewed articles dealing with the science of lignocellulosic materials, chemicals, and their uses. We also support undergraduate scholarship in our academic department, including tuition payment, opportunities for pre-editing work, and support for undergraduates to attend conferences, etc.
  • Editorialpp 3-5Zhu, S., Wang, K., Huang, W., Huang, W., Cheng, B., Chen, J., Zhang, R., Chen, Q., and Wu, Y. (2016). "Acid-catalyzed hydrolysis of lignocellulosic biomass in ionic liquids for ethanol production: Opportunities & challenges," BioRes. 11(1), 3-5.AbstractPDF
    Lignocellulosic biomass (LB) is potentially a relatively inexpensive and abundant feedstock for ethanol production. One of the most challenging steps during the lignocellulosic ethanol production is to convert the carbohydrates in LB to the fermentable reducing sugars (FRS) in an economically viable and environmentally friendly way. The acid-catalyzed hydrolysis of LB in ionic liquids (ILs) has provided a promising technical tool to improve upon the traditional FRS production process. Compared to the conventional FRS production process from LB via the acid or enzymatic hydrolysis method, it has many advantages, such as a simplified process, mild reaction conditions, low acid consumption, and low equipment investment. However, there are still some technical challenges that need to be solved regarding its use at an industrial scale, for example, improving its reaction selectivity, developing effective methods to separate the FRS and ILs, and alleviating the negative effect of the remaining ILs in FRS on subsequent ethanol fermentation. This editorial will give a brief discussion about opportunities and challenges of the acid catalyzed hydrolysis of LB in ILs for ethanol production.
  • Editorialpp 6-7Gangwar, A. K., Prakash, N. T., and Prakash, R. (2016). "Questioning conventional wisdom regarding the most suitable sequence of enzyme usage in pulp bleaching," BioRes. 11(1), 6-7.AbstractPDF
    Increased public scrutiny and governmental legislation towards the pulp and paper industries have motivated industrialists and researchers to seek improved bleaching sequences having the potential to minimize pollutants in bleach effluent generated during manufacturing of paper. Discovery of toxic chlorinated organics and their components in bleach effluents has focused people’s attention towards finding alternative ways of bleaching pulp. Use of enzymes at industrial scale has become well known, but still it is not clear whether the sequence of enzymatic treatment most often employed in industrial applications represents the best overall practice. The point of enzyme addition is critically important to maximize benefits. Many publications describe the use of an enzyme treatment stage before the use of chemicals in a bleaching process. Insufficient attention has been paid to the alternatives of adding an enzyme in between chemical bleaching agents (intermediate) or at the end of the bleaching process.
  • Researchpp 8-20Xu, M., Bao, W., Xu, S., Wang, X., and Sun, R. (2016). "Porous cellulose aerogels with high mechanical performance and their absorption behaviors," BioRes. 11(1), 8-20.AbstractArticlePDF

    Porous cellulose aerogel materials are attracting increasing interest due to their promising potential in multiple fields. In this paper, highly porous and mechanically strong cellulose aerogels were successfully prepared from microcrystalline cellulose and dissolving pulp in ionic liquid BmimCl via a sol–gel polymerization method. The surface morphology and physical properties were characterized by scanning electron microscopy, X-ray diffraction, and compression tests, etc. The differences in microstructure, crystalline structure, and mechanical performance of these two kinds of cellulose aerogels were studied and compared. Moreover, the two cellulose aerogels were used as adsorbents to remove dye, oil, and organic solvents. The kinetics and equilibrium capacity were investigated. Results indicate that the cellulose aerogels with high degrees of polymerization have much better mechanical strength and adsorption properties than the cellulose aerogels with low degrees of polymerization.

  • Researchpp 21-32Zhao, Y. Y., Li, X. H., Wu, S. B., and Li, Y. M. (2016). "Temperature impact on the hydrothermal depolymerization of Cunninghamia lanceolata enzymatic/mild acidolysis lignin in subcritical water," BioRes. 11(1), 21-32.AbstractArticlePDF

    In the present work, enzymatic/mild acidolysis lignin (EMAL) was isolated from the raw material Cunninghamia lanceolata, and hydrothermal depolymerization was carried out in subcritical water (from 250 to 350 °C) using a cylindrical autoclave. The results revealed that the lowest yield of solid residue and highest liquid product yield were achieved at 325 °C. The liquid products were primarily composed of phenolic monomers and oligomers. As the reaction temperature increased, repolymerization of the liquid products and dehydrogenation and deoxidation of the solid residues occurred. The high heating value (HHV) of the residues was larger than that of the EMAL, and it reached a maximal level at 275 °C. Hydrothermal depolymerization and condensation reactions took place simultaneously even under mild conditions (250 °C). Carbonization of the EMAL was remarkable when the reaction temperature reached 325 °C.

  • Researchpp 33-43Ruman, D., Gaff, M., Gašparík, M., and Babiak, M. (2016). "Experimental evaluation of joints using thin steel angles for wood structures," BioRes. 11(1), 33-43.AbstractArticlePDF

    The load-bearing capacity of joints using thin steel elements for wood buildings was considered. Six variants of a specific type of joint consisting of two wood elements in a ceiling structure joined by steel angles were experimentally tested. These variants differed in utilization of nails as well as screws (of various lengths) for wood. Another observed factor was the percentage of holes filled in the angles. In this work the percentage of holes filled means how many of the holes in the steel angles were filled by nails/screws. The evaluation characteristic was the maximum loading force at the breaking point. Based on the results, a set of recommendations for designing a specific type of joint with steel angles was formulated. The results showed that during loading of the joints, tensile stresses occur in the direction perpendicular to the fibers, which causes a failure of the wood parts of the joints.

  • Researchpp 44-53Nosek, R., Holubcik, M., and Jandacka, J. (2016). "The impact of bark content of wood biomass on biofuel properties," BioRes. 11(1), 44-53.AbstractArticlePDF

    Woody biomass is an abundant, renewable energy source. Forest residue is the fraction remaining after harvest and the outtake of wood timber, including tree tops and bark. Compared with the wood portion, bark has a wide variation of ash content. Wood usually has a relatively low ash content, while bark has considerably higher ash content, which may generate clinker in the furnace and thereby tends to create more demand for maintenance. High ash content also generates more particulate emissions. Different types of bark were studied in the present work in terms of their effect on energy content, moisture, and ash content. The ash content of three different samples (Norway spruce, birch, and European beech) were measured at 550 and 815 °C. The results showed the impact of bark content on all parameters, in particular the calorific value and ash content. The ash content increased with increasing bark content. The addition of 1% bark content resulted in increases of ash content in the range 0.033 to 0.044%.

  • Researchpp 54-70Li, Z., Yu, Y., Sun, J., Li, D., Huang, Y., and Feng, Y. (2016). "Effect of extractives on digestibility of cellulose in corn stover with liquid hot water pretreatment," BioRes. 11(1), 54-70.AbstractArticlePDF

    Many herbaceous lignocelluloses suitable for ethanol production have high extractives contents, such as some straws and corn stover. The high extractives content might affect pretreatment or enzymatic hydrolysis. In this study, extractives were removed from corn stover, and then extractives-free corn stover and ordinary corn stover were respectively pretreated using a liquid hot water (LHW) method and hydrolyzed to evaluate the effect of extractives on cellulose digestibility. Extractives-free corn stover presented higher cellulose digestibility than ordinary corn stover after the same pretreatment conditions. A total of 87.3% of cellulose was digested in extractives-free corn stover, compared to 71.0% in ordinary corn stover, after pretreatment at 200 °C for 20 min. It is speculated that some water-soluble extractives could buffer H+ ions from water and acetic acid during LHW pretreatment process, reducing xylan removal. Another reason for these results might be that some extractives could condense on corn stover after LHW pretreatment, which hinders cellulose hydrolysis.

  • Researchpp 71-86Dubinyová, L., Jablonský, M., Varga, Š., Fikar, M., and Katuščák, S. (2016). "Cellulose materials identification: The effect of dimensionality of colour photography data," BioRes. 11(1), 71-86.AbstractArticlePDF

    This paper describes a simple rapid staining microcolorimetric method for analytical fibre material identification using colour vectors of stained fibre material photography. The number of morphological characteristics (nM), number of stains (nS), colour information dimensionality (nDC), and picture elementary points number (npx) can play a key role in distinguishing fibre materials, correct identification, discriminatory power dP (%), and efficacy. Experiments were performed to achieve the most accurate results with a minimum volume of data; the dimensionality reduction was made experimentally by setting nM = 0, nS = 1, nDC <1, 3>, and the effect of number of pixels on the dP (%) was measured. The correct identification was achieved by less than 100 pixels when using 2 colour vectors, and by less than 50 pixels when using 3 colour vectors: R, G, and B. The real area of the pixels used for correct identification was less than 0.1 mm2 in the used model system of the cellulose fibre materials.

  • Researchpp 87-94Wu, C., Bing, L., Li, S., Yu, D., and Wang, D. (2016). "Effect of coagulating agents on lignin and oligosaccharide contents in pre-hydrolysis liquor obtained in the production of dissolving pulp from poplar residual slabs," BioRes. 11(1), 87-94.AbstractArticlePDF

    Pre-hydrolysis is an important step in the poplar residual slab dissolving pulp production process, as it aids in removing as much hemicellulose as possible from the cellulose fibers. In the pre-hydrolysis process, a portion of lignin also dissolves, along with the hemicelluloses. The presence of lignin in prehydrolysis liquor (PHL) is detrimental to the separation of xylo-oligosaccharide from the prehydrolysis liquor. This study researched lignin removal from PHL with three coagulating agents, namely aluminum sulfate (alum), polyaluminum chloride (PAC), and polydiallyldimethyl ammonium chloride (pDADMAC). It was found that the removal of lignin increased as the dosage of the alum, PAC, and pDADMAC increased. Additionally, the highest retention of xylo-oligosaccharide in the PHL occurred at dosages of 120 mg/L for alum and 160 mg/L for PAC and pDADMAC. The contents of the other oligosaccharides in PHL fluctuated irregularly with increasing dosages of the alum, PAC, and pDADMAC.

  • Researchpp 95-104Ćilerdžić, J., Stajić, M., and Vukojević, J. (2016). "Activity of Mn-oxidizing peroxidases of Ganoderma lucidum depending on cultivation conditions," BioRes. 11(1), 95-104.AbstractArticlePDF

    Trunks and stumps of various deciduous species act as natural habitats for Ganoderma lucidum. The chemical composition of their cell wall affects the development of fungal ligninolytic enzyme system as well as its ability to degrade lignin from the plant cell wall. Additionally, numerous compounds structurally similar to lignin can be degraded by the G. lucidum enzyme system which could take important roles in various biotechnological processes. The laccases, which are the dominant enzymes synthesized by G. lucidum, have been studied more extensively than the Mn-oxidizing peroxidases. Therefore, this study aimed to create the dynamics profile of Mn-oxidizing peroxidases activities in four G. lucidum strains, classifying and determining their properties depending on the cultivation type and plant residue as a carbon source in the medium, as well as to establish whether intraspecific variety exists. The findings suggest that submerged cultivation appeared to be a more appropriate cultivation type for enzyme activities compared with solid-state cultivation, and oak sawdust was a better carbon source than wheat straw. Under the optimum conditions, on day 14, G. lucidum BEOFB 431 was characterized by the highest levels of both Mn-dependent and Mn-independent peroxidase activities (4795.5 and 5170.5 U/L, respectively). Strain, cultivation type, and carbon source were factors that affected the profiles of Mn-oxidizing peroxidases isoenzymes.

  • Researchpp 105-125Choi, B., Chung, J. Y., Bae, H. J., Bae, I., Park, S., and Bae, H. (2016). "Functional characterization of cinnamyl alcohol dehydrogenase during developmental stages and under various stress conditions in kenaf (Hibiscus cannabinus L.)," BioRes. 11(1), 105-125.AbstractArticlePDF

    In this study, the entire gene encoding cinnamyl alcohol dehydrogenase in kenaf (HcCAD2) was cloned and characterized. CAD is a key enzyme in the last step of lignin biosynthesis. The full-length HcCAD ortholog is composed of a 1,074-bp open reading frame (ORF) encoding 357 amino acids (KM044582). BlastP and a phylogenetic study revealed that the deduced amino acid sequences share the highest similarity with Gossypium hirsutum (ABZ01817) (89%). Upon real-time PCR analysis, HcCAD1 (HM151380) and HcCAD2 were highly up-regulated in 4-week-old stem and mature flower tissues, which was matched with histochemical staining and lignin component analysis. The expression patterns of the two genes differed in response to wound, cold, NaCl, SA, H2O2, ABA, MeJA, and drought. CAD enzyme activity was measured with various aldehydes as substrates to form corresponding alcohols. The results indicated that the preferred substrates were coniferyl and sinapyl aldehydes with high catalytic efficiency.

  • Researchpp 126-139Gan, S., Zakaria, S., Ng, P., Chia, C. H., and Chen, R. S. (2016). "Effect of acid hydrolysis and thermal hydrolysis on solubility and properties of oil palm empty fruit bunch fiber cellulose hydrogel," BioRes. 11(1), 126-139.AbstractArticlePDF

    Cellulose hydrogel was produced from pretreated oil palm empty fruit bunch fiber (EFB) that went through acid hydrolysis and thermal hydrolysis. The pretreated EFB was dissolved in LiOH/urea aqueous solution using the rapid dissolution method and was subjected to a crosslinking process with the aid of epichlorohydrin to form hydrogel. The effects of both hydrolyses’ time on average molecular weight (Mŋ), solubility, and properties of EFB hydrogels were evaluated. Both hydrolyses led to lower Mŋ, lower crystallinity index (CrI) and hence, resulted in higher cellulose solubility. X-ray diffraction (XRD) characterization revealed the CrI and transition of crystalline structure of EFB from cellulose I to II. The effects of hydrolysis time on the transparency, degree of swelling (DS), and morphology of the regenerated cellulose hydrogel were also investigated using an ultraviolet-visible (UV-Vis) spectrophotometer and a Field emission scanning electron microscope (FESEM), respectively. These findings provide an efficient method to improve the solubility and properties of regenerated cellulose products.

  • Researchpp 140-158Tanninen, P., Leminen, V., Kainusalmi, M., and Varis, J. (2016). "Effect of process parameter variation on the dimensions of press-formed paperboard trays," BioRes. 11(1), 140-158.AbstractArticlePDF

    The dimensional accuracy of packages has a great effect on operation of the production and supply chain. In this research, the dimensional accuracy of trays made of polymer-coated paperboard and the effect of all essential press forming process parameters on outer dimensions of the trays were studied to obtain data for the press forming and lid sealing process optimization and for the forming tool design. Paperboard trays were analysed and measured with a quality monitoring system that includes a smart camera and a backlit table. Trays with varying dimensions were sealed to investigate the effect of the package size and the product weight to the residual oxygen in the package’s headspace gas. Results showed that all heat related parameters, i.e.,mould temperatures, dwell time, and pressing speed can be used to adjust the outer dimensions of the paperboard tray. Lid sealing process was found to reduce size of the trays and even out size differences substantially. All produced trays were measured to be bigger both in length and in width compared to the design values of the mould set. Therefore the mould set has to be designed undersized to obtain trays with certain outer dimensions.

  • Researchpp 159-173Chen, Q., Endo, T., and Wang, Q. (2016). "Characterization of microcrystalline cellulose after pretreatment with low concentrations of ionic liquid-H2O for a pyrolysis process," BioRes. 11(1), 159-173.AbstractArticlePDF

    Microcrystalline cellulose (MCC) samples pretreated by ionic liquid (ILs)-H2O mixtures were studied for application in a pyrolysis process. A 1-ethyl-3-methylimidazolium methanesulfonate [Emim][MeSO3]-H2O mixture with solid acid catalyst Nafion®NR50 was used in the pretreatment process. A lower amount of hydrogen bonding between neighboring pretreated MCC chains resulted from a less ordered cellulose structure, leading to lower crystallinity, decreased molecular weight and reduced thermal stability. The pyrolysis result showed that the yields of char were lower, the average reaction rate increased, and the DTG peak temperature decreased relative to the untreated MCC. The amount and concentration of the hydrogen gas obtained from the pyrolysis of sample 90(20) (4.00 mmol/g-sample) was higher than that obtained from the pyrolysis of the MCC (3.26 mmol/g-sample). This study explores MCC (pretreated by ionic liquid-H2O mixtures) with a recyclable solid acid catalyst under varying pretreatment conditions, as a potential raw feed material, to be applied in the pyrolysis process.

  • Researchpp 174-181Wang, J., Gao, Z., Tu, D., He, Z., Lin, X., and Sun, J. (2016). "Dimensional stability of board manufactured with wood-based panel laths," BioRes. 11(1), 174-181.AbstractArticlePDF

    The overall objective was to use waste plywood and medium density fiberboard (MDF) to manufacture a new type of board. The dimensional stability of board was improved by mechanical inhibition between laths along the thickness direction. Its modulus of rupture (MOR) and dimensional stability were tested to determine whether it satisfied the Chinese national standard. The innovational points lie in the treatment to improve dimensional stability and raw materials. The MOR of board manufactured with MDF was superior to that manufactured with plywood, although the MOR of MDF was lower than the MOR of plywood. The IT and DT of new manufactured boards decreased more than 33.48% compared to the raw materials. Besides, the warpage and thickness variation tended to be stabilized with cyclical tests continuing. This result indicated that the treatment of mechanical inhibition between laths along thickness direction could improve the dimensional stability of boards. In addition, MDF was a suitable raw material for the new board.

  • Researchpp 182-194Qin, L., Lin, L., and Fu, F. (2016). "Microstructural and micromechanical characterization of modified urea-formaldehyde resin penetration of wood," BioRes. 11(1), 182-194.AbstractArticlePDF

    Characterization of the adhesive penetration behavior in wood is highly desired for optimizing the manufacturing processes and product properties. In this study, modified urea-formaldehyde (UF) adhesive was used to prepare glued laminated timber (Cryptomeria fortunei Hooibrenk). The depth of gross penetration was measured by fluorescence microscopy (FM), which showed the UF passed through 1.5 to 3.5 earlywood tracheids (with an average penetration depth of 88.95 ± 27.49 μm) or 0.5 to 4.0 latewood tracheids (with an average penetration depth of 36.39 ± 15.14 μm). In addition, the distribution of cell wall penetration was observed clearly by confocal laser scanning microscopy (CLSM). The adhesive was found to diffuse into the cell walls of surface tissues embedded in the UF. To verify the results from CLSM, the mechanical properties of cell walls with and without adhesive penetration were measured through nanoindentation (NI). The reduced elastic modulus of exposed cell walls (18.10 GPa) was roughly equal to that of fully filled cell walls (17.68 GPa) but significantly greater than that of reference ones (15.71 GPa). The hardness showed a similar variation trend for these three types of cell walls. Combining the three techniques, both the microstructure and micromechanics of the adhesive penetration behavior can be quantitatively identified in a complementary manner.

  • Researchpp 195-208Klímek, P., Wimmer, R., Brabec, M., and Sebera, V. (2016). "Novel sandwich panel with interlocking plywood kagome lattice core and grooved particleboard facings," BioRes. 11(1), 195-208.AbstractArticlePDF

    A new sandwich composite structure was prepared that utilizes classic wood-based composites as the core and face materials. Particleboards were used as faces, which covered a plywood-made iso-grid core. A new type of core-face fixation was suggested and assessed. The sandwich panels can be regarded as lightweight, as their density was below 400 kg/m3. Digital image correlation (DIC) was used to determine Poisson’s ratios and obtain additional insight into the deformation behavior of the sandwich panel. DIC was also employed to assess the core-face bonding, which was based on imprinted grooves on one side of the particleboard face. The results include strength in edgewise and flatwise compression and flexural properties. The latter were determined through three-point bending tests. Comparable strength properties were found relative to the literature, which means that this new type of sandwich panel demonstrates a competitive property profile. It was concluded that the developed sandwich panel is versatile, and the hollow spaces in the core can be filled with insulation materials such as fibers or foams. Surfaces can also be covered with some overlay, delivering improved bending performance.

  • Researchpp 209-222Mračková, E., Krišťák, L., Kučerka, M., Gaff, M., and Gajtanska, M. (2016). "Creation of wood dust during wood processing: Size analysis, dust separation, and occupational health," BioRes. 11(1), 209-222.AbstractArticlePDF

    Mechanical separators and fabric filters are being used to remove airborne fine particles generated during the processing and handling of wood. Such particles might have a harmful effect on employee health, not only in small- but also in large-scale wood processing facilities. The amount of wood dust and its dispersion conditions vary according to geometric boundary conditions. Thus, the dispersion conditions could be changed by changing the linear size of the particles. Moreover, the smaller the particles are, the more harmful they can be. It is necessary to become familiar with properties, from a health point of view, of wood dust generated from processing. Wood dust has to be sucked away from the processing area. The fractional separation efficiency of wood dust can be improved using exhaust and filtering devices. Filtration efficiency depends on moisture content, particle size, and device performance. Because of the carcinogenicity of wood dust, the concentration of wood dust in air has to be monitored regularly. Based on the results hereof, a conclusion can be made that both mechanical separators of types SEA and SEB as well as the fabric filters with FINET PES 1 textile are suitable for the separation of wet saw dust from all types of wooden waste produced within the process.

  • Researchpp 223-234Fajdiga, G., Zafošnik, B., Gospodarič, B., and Straže, A. (2016). "Compression test of thermally-treated beech wood: Experimental and numerical analysis," BioRes. 11(1), 223-234.AbstractArticlePDF

    Experimental and numerical analysis of a compression test carried out on samples of as-received and thermally-treated beech (Fagus sylvatica L.) wood is presented. In a normal climate, samples with the dimensions of 20 x 20 x 20 mm were exposed to static compressive loads parallel and transverse to the grain. Afterwards, the test was modelled using the finite element method. It was confirmed that, after thermal modification, the wood’s density decreased and the stiffness in both tested directions increased. After the thermal treatment, the strength of beech wood increased in the direction parallel to the grain and decreased in the direction transverse to the grain. Based on the comparison of experimental and numerical results, it is possible to use the hyperelastic constitutive law to reasonably model the force and displacement obtained in the compression test samples.

  • Researchpp 235-248Moradbak, A., Tahir, P. M., Mohamed A. Z., and Halis, R. (2016). "Alkaline sulfite anthraquinone and methanol pulping of bamboo (Gigantochloa scortechinii)," BioRes. 11(1), 235-248.AbstractArticlePDF

    Alkali ratios and cooking time of the alkaline sulfite anthraquinone (AQ) and methanol (ASAM) pulping process of bamboo (Gigantochloa scortechinii) were studied. Bamboo chips were cooked at three different levels of sodium hydroxide and cooking time, namely 14, 16, or 18% for 60, 90, or 120 minutes. Pulping parameters that remained constant were the use of 0.5% ethylene diamine tetraacetic acid (EDTA), with an 80/20 ratio Na2SO3/NaOH, 0.1% anthraquinone, 15% methanol, and a temperature of 170 °C in the cooking process. Samples prepared using 14% NaOH and 90 min of cooking time resulted in the highest pulp yield, 52.4%, and a Kappa number of 18.1. It seems that 16% sodium hydroxide and 90 min of cooking time are the most appropriate cooking conditions, giving a 49.1% pulp yield and 14.2 Kappa number. The quality of bamboo pulp produced by the ASAM pulping process was found to be beneficial for the use in paper and board manufacturing.

  • Researchpp 249-266Lou, Y., Joseph, S., Li, L., Graber, E. R., Liu, X., and Pan, G. (2016). "Water extract from straw biochar used for plant growth promotion: An initial test," BioRes. 11(1), 249-266.AbstractArticlePDF

    The production of energy and biochar from the pyrolysis of straw and other agricultural residues is a developing industry that holds the potential to reduce air pollution from in-field burning, recycle nutrients, reduce chemical fertilizer inputs, and improve soil quality. Use of biochar in agriculture is undergoing tests globally. Water-soluble organic compounds from pyrolysis residue containing humic substances, low-molecular weight acids, and neutral compounds and inorganic elements containing macro and micro nutrients have been shown to be beneficial for plant growth. In the present study, crop straw biochars were extracted into hot water and the extracts tested for their effect on growth of Chinese cabbage. The extracts were sprayed 10 times at three different dilutions throughout the growing period. The extracts were characterized for inorganic elements by ICP-MS and for organic compound type by LC-OCD and FTIR. Results showed that extracts of both wheat and maize straw biochar can significantly increase the yield, vitamin C content, and soluble protein content while decreasing the nitrate content of the cabbage at dilutions of 50 or 100 times. Water extract from biochar was found to have great potential as a liquid amendment in agricultural.

  • Researchpp 267-280Zhou, J., Chen, L., Fu, W., Chen, Z., Zhao, Z., Cheng, W., and Zhang, Z. (2016). "Preparation and performance evaluation of bamboo lumber prepared by assembly and glue-curing of naturally arc-shaped segments with finger joints," BioRes. 11(1), 267-280.AbstractArticlePDF

    Using bamboo to replace wood has great significance for the protection of forests. This work presents the concept of the reorganization of arc bamboo sheet to produce recombined arc-segment bamboo lumber (RABL). Several key preparation technology parameters were investigated. Results showed that when the phenol resin (PF) double-sided adhesive quantity was 250 g/m2, unit pressure was 2.0 MPa, screen voltage was 4200 V, screen current was 1.5 A, and hot pressing time was 30 s/mm, the modulus of rupture (MOR) of the RABL was 105 MPa and the modulus of elasticity (MOE) was 5000 MPa. These parameters mean that RABL could be used as the structural material for load-bearing situations. If ignoring the machining allowance, the bamboo utilization rate of the RABL was 1.72 times that of the rectangular element recombinant bamboo and the adhesive level of the RABL was 0.6 times that of the rectangular element recombinant bamboo. When considering the machining allowance, the bamboo utilization rate of the RABL was 1.8 times that of the rectangular element recombinant bamboo, and the adhesive volume of the RABL was 0.56 times that of the rectangular element recombinant bamboo, so RABL has obvious advantages.

  • Researchpp 281-295Espinoza, O., Trujillo, V. R., Mallo, M. F. L., and Buehlmann, U. (2016). "Cross-laminated timber: Status and research needs in Europe," BioRes. 11(1), 281-295.AbstractArticlePDF

    In the 20 years since its invention in Europe, cross-laminated timber (CLT) has become a widely used construction material in parts of the old continent and has started to attract global attention. CLT possesses numerous advantages as a construction material, including its superior structural and environmental performance, as well as the speed and efficiency with which CLT buildings can be erected. In this study, European engineers were surveyed to learn about their current level of awareness of CLT, the major barriers to CLT adoption, and about the most pressing research needs to advance the use of CLT as a construction material. The study used a web-based survey with a convenience sample of 93 different kinds of timber and civil engineers and/or researchers, most of which belong to a European CLT research network. Results showed that participants think that, in general, the level of awareness about CLT among developers, construction managers, engineers, architects, and construction managers, is low. The majority of perceived barriers for CLT adoption involved its building code compatibility and the availability of technical information. The most pressing research needs for CLT development, according to respondents, are in the areas of structural performance and connections, moisture performance, and market research.

  • Researchpp 296-305Tolvaj, L., Popescu, C. M., Molnar, Z., and Preklet, E. (2016). "Effects of air relative humidity and temperature on photodegradation processes in beech and spruce wood," BioRes. 11(1), 296-305.AbstractArticlePDF

    Spruce and beech samples were irradiated by UV light in humid (100% air humidity) and dry conditions to clarify the effects of vapor on photodegradation. UV-irradiated samples were also soaked in distilled water for comparison. The color change and the IR absorption spectra were measured. The wet condition generated considerably greater discoloration than did the dry condition. The intensity of the color change was higher at elevated temperature (53 °C) than at 32 °C. The results showed that the presence of water as vapor increased the degradation of lignin. The nonconjugated carbonyl groups absorbing around 1760 cm-1 were found not to be stable, and the number of these chemical groups decreased in the presence of vapor when compared against the dry condition. The rising temperature amplified this degradation effect.

  • Researchpp 306-323Nurhazwani, O., Jawaid, M., Paridah, M. T., Abdul , J. H., and Hamid, S. A. (2016). "Hybrid particleboard made from bamboo (Dendrocalamus asper) veneer waste and rubberwood (Hevea brasilienses)," BioRes. 11(1), 306-323.AbstractArticlePDF

    This study investigated adhesion properties, such as buffering capacity and wettability, of bamboo and rubberwood and evaluated the physical and mechanical properties of hybrid particleboard made from bamboo (B) veneer waste and rubberwood (RW) particles. The bamboo had an acidic pH value with a high buffering capacity compared with rubberwood. Hybrid bamboo-rubberwood particleboard displayed better mechanical properties compared to 100% bamboo and rubberwood particleboard. All hybrid particleboard panels passed and fulfilled the minimum standard requirements, except for thickness swelling and water absorption tests. However, for thickness swelling test, only boards consisting of 50B:50RW and 30B:70RW passed and fulfilled the minimum TS requirements of the British Standard EN 317 (1993). Panels made from 100% bamboo veneer waste displayed the highest modulus of rupture (MOR) and modulus of elasticity (MOE) values, 15.30 N/mm2 and 2650.14 N/mm2, respectively. Hybrid particleboard panels exhibited better screw withdrawal compared with panels made of only bamboo or rubberwood particles. It is concluded that bamboo veneer waste enhances the quality of particleboards, especially in terms of mechanical strength. Thus, bamboo veneer waste can decrease the dependence of the particleboard industry on rubberwood.

  • Researchpp 324-335Cirule, D., Meija-Feldmane, A., Kuka, E., Andersons, B., Kurnosova, N., Antons, A., and Tuherm, H. (2016). "Spectral sensitivity of thermally modified and unmodified wood," BioRes. 11(1), 324-335.AbstractArticlePDF

    The chemical structure of wood changes significantly during thermal modification, significantly influencing the behaviour of wood during weathering. In this study, the effect of different wavelength ranges on thermally modified and unmodified aspen (Populus tremula L.) wood during solar irradiation was investigated. Irradiation was performed by exposing wood to natural solar irradiation under filters transmitting different wavelength ranges. For both woods, the magnitude of characteristic change (discolouration, changes in reflectance, and chemical composition) clearly depended on the solar wavelength bands, but the trends of the changes differed. For unmodified wood, the magnitude of the characteristic changes increased as the portion of short-wavelength radiation in the light increased. However, UV radiation was not found to be the dominant factor influencing changes in thermally modified wood during solar irradiation. The colour and chemical structure of thermally modified wood changed substantially for all studied irradiation conditions.

  • Researchpp 336-353Xu, Y., Wang, J., Qian, X., Zuo, L., and Yue, X. (2016). "Effects of supplementary alkali after alkaline peroxide treatment on the properties of bleached kraft pine fluff pulp," BioRes. 11(1), 336-353.AbstractArticlePDF

    Effects of dual-treatment on cellulose fiber quality, micro-structure appearance, crystalline structure, hydrogen bonds, and surface elements were analyzed using a fiber quality analyzer (FQA), scanning electron microscope (SEM), wide-angle X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS), respectively. In comparison to the untreated pulp, the brightness of pulp increased by 51.71%, whereas the apparent density and burst strength index of the pulpboard decreased by 11.76% and 48.18%, respectively. The absorption time, absorbability, and bulk of the fiber obtained by defibering the pulpboard decreased by 47.40%, 8.33%, and 5.32%, respectively, when it had been subjected to supplementary alkali. With the analysis of FQA and SEM, fiber swelled and curled, its surface was relatively smooth, and filaments of its partial surface area were exposed as a result of the supplementary alkali. Additionally, XRD analysis, FT-IR analysis, and XPS scanning spectra all showed that the crystallinity degree of fiber decreased by 45.10%, indicating more crystal structures were converted into amorphous structures. The proportion of total intra-molecular hydrogen bond intensity to total hydrogen bonds increased. The –OH content on fiber surface only decreased by 4.15%, compared with those of the untreated pulp, when the fiber was subjected to the two-step chemical treatment.

  • Researchpp 354-364Derikvand, M., and Pangh, H. (2016). "A modified method for shear strength measurement of adhesive bonds in solid wood," BioRes. 11(1), 354-364.AbstractArticlePDF

    An experimental method was developed in this investigation to evaluate the shear strength of adhesive bonds in solid wood materials. The new method was tested against the standard test methods described in ASTM D-905, EN 205, and EN 302-1. Specimens were constructed of Oriental Beech (Fagus orientalis L.) and bonded with three different wood adhesives. Using the proposed method in the study, unintentional errors in cutting and testing processes of the shear specimens were decreased, which led to a decrease in the variability of the results. The worst stability was observed in the data obtained when the EN 205 and ASTM D-905 standard methods were used.

  • Researchpp 365-372Marounek, M., Volek, Z., Skřivanová, E., Taubner, T., and Dušková, D. (2016). "Comparative study on the hypocholesterolemic activity of amidated polysaccharides and psyllium," BioRes. 11(1), 365-372.AbstractArticlePDF

    The effects of amidated carboxymethylcellulose, amidated pectin, and psyllium on serum and hepatic cholesterol, hepatic fat, and fecal output of sterols were examined in female rats. Rats were fed a diet supplemented with cholesterol (0 or 10 g/kg) and palm fat. Amidated cellulose at 30 g/kg significantly decreased the serum and hepatic concentration of cholesterol by 28.1% and 64.6%, respectively. Corresponding values in rats fed amidated pectin were 28.9% and 72.4%. The effects of psyllium were similar, but less pronounced. Amidated pectin significantly increased the fecal output of cholesterol, total neutral sterols, and total sterols by 49.1%, 31.9%, and 31.0%, respectively. Amidated cellulose and psyllium increased the fecal excretion of total sterols by 1.1% and 5.5%, respectively. In the feces of rats fed amidated cellulose, a small amount of conjugated bile acids was detected (0.83% of total bile acids). In these rats, the lowest expression of hepatic cholesterol 7α-hydroxylase was detected, corresponding to the low fecal output of bile acids. We conclude that the hypocholesterolemic effects of both amidated polysaccharides were similar in spite of their different affinity to sterols.

  • Researchpp 373-384Zhang, G., Zheng, H., Liu, G., Wang, P., and Xiang, R. (2016). "Synthesis and application of a multifunctional fluorescent polymer based on coumarin," BioRes. 11(1), 373-384.AbstractArticlePDF

    A multifunctional fluorescent polymer based on coumarin (MFPC) was synthesized using a four-step synthetic route. To obtain the target compound, 7-amino-4-methylcoumarin, coumarin fluorescent monomer (CFM), and ultraviolet absorber monomer (UVAM) were prepared. By the reaction of CFM, UVAM, trimethyl-2-methacroyloxyethylammonium chloride (DMC), and acrylamide (AM) as a linker, a new multifunctional fluorescent polymer was synthesized. The structure of the MFPC was characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H-NMR) spectroscopies. The optical properties of MFPC were measured by ultraviolet-visible (UV-vis) and fluorescence spectroscopies, in aqueous solution. The integration effect between MFPC and paper was tested by scanning electron microscopy. The application performance of MFPC on paper was evaluated by measuring the surface strength, smoothness, and whiteness using the printability tester and the UV accelerated aging test. Results indicated that the MFPC had good solubility in water. It also exhibited a positive effect on the light stability and surface strength of paper as a light stabilizer, fluorescent brightener, and surface sizing agent.

  • Researchpp 385-399Peng, H., Liu, Y., Peng, W., Zhang, J., and Ruan, R. (2016). "Green synthesis and stability evaluation of Ag nanoparticles using bamboo hemicellulose," BioRes. 11(1), 385-399.AbstractArticlePDF

    The unique physico-chemical properties of silver nanoparticles (Ag NPs) have opened up the opportunity for their use in many promising physico-chemical and biomedical applications. In this study, an economically feasible approach to green synthesis of silver nanoparticles (Ag NPs) is described using hemicellulose from bamboo. Simultaneously, glucose was used as the reducing agent, and distilled water was used as the reaction medium. UV-vis spectroscopy and transmission electron microscopy were used to investigate the surface plasmon behavior, morphology, and particle size of the Ag NPs. Hemicellulose alone could not reduce Ag+ to Ag0. The formation rate of the nanoparticles was accelerated when high amounts of glucose were added. Small particle sizes were obtained when high concentrations of hemicellulose were used. The stability of the Ag NPs synthesized using different concentrations of hemicellulose from 0.5 mg/mL to 8.0 mg/mL was also evaluated. Higher initial hemicellulose concentrations produced more stable Ag NPs. The average particle sizes of the NPs after storing for 160 days at 4 °C were still smaller than 10 nm when the initial hemicellulose concentrations were 6.0 and 8.0 mg/mL.

  • Researchpp 400-413Samoraj, M., Tuhy, Ł., Rusek, P., Rój, E., and Chojnacka, K. (2016). "Pilot plant conversion of blackcurrant seeds into new micronutrient fertilizer biocomponents via biosorption," BioRes. 11(1), 400-413.AbstractArticlePDF

    A new approach for micronutrient fertilizer biocomponent production based on blackcurrant seeds is presented. Blackcurrant seeds constitute a by-product from the production of jellies, jams, and juices. New environmental-friendly fertilizers with micronutrients were produced in the pilot plant as alternative sustainable fertilizers to conventional options. Post-extraction residues, obtained after supercritical CO2 extraction was conducted on blackcurrant seeds, were used. In each process, 15 kg of biosorbent was used. Good sorption capacity was achieved (6.48 mg/g for Zn(II), 13.9 mg/g for Cu(II) and 5.88 mg/g for Mn (II)). The adsorption kinetics was described using different kinetic models; the most suitable were the Nelson-Yoon and Thomas models. The new preparation has application-friendly form (micro-granules) and is nontoxic. For a dose of 2.5 kg of zinc, 1 kg of manganese, and 0.5 kg of copper per hectare (often used in vegetable fertilization), approximately 600 kg of mixed end product is required. The cost of fertilization with current scale technology will be about four times higher than that of conventional technology (including depreciation of equipment), but with process scale-up, it is possible to reduce costs even twice over.

  • Researchpp 414-425Zakikhani, P., Zahari, R., Sultan, M. T. H., and Majid, D. L. (2016). "Thermal degradation of four bamboo species," BioRes. 11(1), 414-425.AbstractArticlePDF

    Bamboo, among other natural plants, has a special structure, with different characterization along the culms and between species. In this study, the thermal stabilities of four bamboo species, named Dendrocalamus pendulus (DP), Dendrocalamus asper (DA), Gigantochloa levis (GL), and Gigantochloa scortechinii (GS), were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) under a nitrogen atmosphere. Each species was divided into three different portions: bottom, middle, and top, and fibres were manually extracted from the specified sections of each species. The thermal analysis of extracted bamboo fibres indicated that the thermal degradation behaviour of each bamboo species varied from bottom to top and between species. However, these variations were lower in DA species compared to GS, GL, and DP, because of minor differences between lignocellulosic components of its three portions. The top and middle portions of the four species degraded at a higher temperature range (314 to 379 °C) than the bottom portions. The results of this study suggest that DA and GS species, according to their thermal stabilities, are most suitable for use as reinforcement in composite materials.

  • Researchpp 426-438Liao, Y., Wang, J., Lu, Z., Gu, J., and Hu, C. (2016). "Effects of heat treatment on durability of merbau heartwood," BioRes. 11(1), 426-438.AbstractArticlePDF

    Merbau wood has been widely used in outdoor applications. However, it has a disadvantage in that its water-soluble extractives readily leach out and stain adjacent materials. Heat treatment is an efficient technique to solve this problem. In this study, the effects of heat treatment on the durability of merbau heartwood were investigated. Merbau heartwood blocks with and without heat treatment were exposed to subterranean termites (Coptotermes formosanus) according to ASTM D3345 (2008), and to brown-rot fungus (Gloeophyllum trabeum) and white-rot fungus (Trametes versicolor) according to ASTM D1413 (2007). The effect of heat treatment on the chemical changes in merbau heartwood and its extracts were investigated by means of Fourier transform infrared spectroscopy (FTIR) and gas chromatography – mass spectrometer (GC/MS). The results show that the extraction yields of merbau heartwood with heat treatment using various solvents significantly decreased. However, termite resistance and fungal resistance of merbau heartwood with and without heat treatment showed no obvious difference. FTIR spectra in the fingerprint region of merbau heartwood and its ethanol-benzene extracts did not show any significant difference between heat-treated and untreated samples. More constituents were identified from the ethanol-benzene extracts of merbau heartwood with heat treatment by means of GC/MS compared to those identified from the ethanol-benzene extracts of untreated merbau heartwood.

  • Researchpp 439-450Sedliačiková, M., Hajdúchová, I., Krištofík, P., Viszlai, I., and Gaff, M. (2016). "Improving the performance of small and medium wood-processing enterprises," BioRes. 11(1), 439-450.AbstractArticlePDF

    This paper investigates the financial aspects of small and medium enterprises (SMEs) in the Slovak wood-processing industry. The aim of the survey was to determine the level of understanding and implementation of financial controlling, and to identify its potential for future implementation. The survey revealed a low level of understanding and implementation of this tool in Slovak wood-processing SMEs, because the use of all analyzed instruments of financial controlling was in small enterprises in a range of 15% and in medium-sized enterprises up to 40%. However, medium-sized enterprises were substantially more equipped than small enterprises at applying and recognizing the benefits of financial controlling. Based on the results of this research, the framework for a standardized model of financial controlling for Slovak wood-processing SMEs was proposed, as a practical way of improving company performance models.

  • Researchpp 451-465Zhang, J., Xu, J. Y., Wang, D. Q., and Ren, N. Q. (2016). "Anaerobic digestion of cassava pulp with sewage sludge inocula," BioRes. 11(1), 451-465.AbstractArticlePDF

    The effectiveness of sludge inocula from a municipal carrousel oxidation ditch wastewater treatment plant was studied for both batch and semi-continuous anaerobic digestion (AD) of cassava pulp. In 1.25-L batch experiments, the following sludge inocula were used: I1 sludge from the hydrolysis acidification tank pre-acclimated with cassava pulp; I2, predigested sludge from the hydrolysis acidification tank; and I3, predigested sludge from the gravity thickening tank. In 1.0-L semi-continuous tests, mesophilic AD of cassava pulp inoculated with I3 was carried out at organic matter loading rates (OLRs) of 1.5 to 12.5 kg volatile solids (VS)/(m3 d), whereas 1.5 to 18.0 kgVS/(m3 d) was used for thermophilic AD. For batch operations, all sludge types could be used as the inoculum for the mesophilic AD of cassava pulp, whereas only I1 was used for thermophilic AD. The maximum specific methane yields were 0.333 and 0.395 m3/kgVSadded, respectively, for mesophilic and thermophilic batch digestion with I1. During semi-continuous AD of cassava pulp inoculated with I3, high specific methane yields of 0.334 to 0.336 m3/kgVSadded were obtained under both mesophilic and thermophilic conditions. For thermophilic AD of cassava pulp with sludge inocula, the range of optimum OLR was 2.5 to 15.0 kgVS/(m3 d), and that was 2.5 to 8.7 kgVS/(m3 d) for mesophilic AD.

  • Researchpp 466-481Hu, J., Li, Y., Yi, L., Guo, H., and Li, L. (2016). "Evaluation of the dyeing properties of basswood veneer treated by dichlorotriazine reactive dye based on gray correlation analysis," BioRes. 11(1), 466-481.AbstractArticlePDF

    The dyeing properties of basswood veneer treated by dichlorotriazine reactive dye in a dip dyeing method were evaluated. The effects of dye concentration, dyeing temperature and time, volume ratio, and dyeing agent were observed relative to the dye-uptake and K/S, using gray correlation analysis. Results showed that various dip dyeing factors had remarkable influences on dye-uptake and K/S, especially dyeing temperature and volume ratio. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) results indicated that reactive dyes were successfully combined with basswood and diffused into the wood fiber lumens and ray cells. Furthermore, thermogravimetric analysis (TGA) demonstrated that the residue of dyed veneer was higher than undyed, and the temperature at maximum degradation rate of dyed and undyed veneer was different.

  • Researchpp 482-491Wang, Q., Wei, W., Li, X., Sun, J., He, J., and He, M. (2016). "Comparative study of alkali and acidic cellulose solvent pretreatment of corn stover for fermentable sugar production," BioRes. 11(1), 482-491.AbstractArticlePDF

    As an immerging lignocellulose pretreatment strategy, cellulose solvent-based pretreatment can break down inter- and intra-molecular hydrogen bonds and disrupt the rigid structure of cellulose. Two cellulose solvent pretreatments were examined and compared in this study: NaOH/urea and concentrated phosphoric acid. Pretreated corn stover substrates were characterized by optical microscopy, confocal laser scanning microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and chemical analyses. It was found that both alkaline- and acid-based cellulose solvent pretreatments can disrupt cell wall structures and cause partial dissolution of the cell wall components. The results indicated that the alkaline-based cellulose solvent was more effective at removing lignin as compared with the phosphoric acid-based cellulose solvent. The initial enzymatic saccharification rate of corn stover pretreated by alkaline-based cellulose solvent was greatly enhanced; complete saccharification of the glucans was achieved within 24 h at an enzyme loading of 15 filter paper units (FPU)/g substrate. The enzymatic digestibility of corn stover pretreated by phosphoric acid was lower than that of the alkaline-based system; this was probably caused by the presence of a high concentration of lignin.

  • Researchpp 492-502Guan, M., Huang, Z., and Zeng, D. (2016). "Shear strength and microscopic characterization of a bamboo bending interface with phenol formaldehyde resins modified with larch thanaka and urea," BioRes. 11(1), 492-502.AbstractArticlePDF

    The aim of this study was to understand the microscopic characteristics of the bamboo bonding interface with phenol formaldehyde resin modified with larch thanaka and urea (PTUF) and its effect on the shear strength of two-ply bamboo laminated lumber. Bleached and carbonized bamboo strips were used, and two assembly patterns (outer-to-outer and inner-to-inner) were adopted to make two-ply bamboo laminated lumber with PTUF. The microstructure of the bonding interface and the bond-line thickness were investigated using a scanning electron microscope. The average depth and effective depth of PTUF on bamboo surfaces were evaluated by fluorescent microscopy characterization. The shear strength of two-ply bamboo laminated lumber was also examined. The results revealed a shallow depth of penetration of PTUF into the bamboo surface that was distributed primarily in the broken cell cavities formed during preparation, as well as between the cell walls. When the assembly pattern was inner-to-inner, the depth of penetration and bond-line thickness were higher, but the shear strength was lower than that of the outer-to-outer pattern. The carbonized bamboo laminated lumber provided a greater resin penetration and bond-line thickness, but lower shear strength, than the bleached bamboo laminated lumber.

  • Researchpp 503-518Tippner, J., Hrivnák, J., and Kloiber, M. (2016). "Experimental evaluation of mechanical properties of softwood using acoustic methods," BioRes. 11(1), 503-518.AbstractArticlePDF

    This paper presents an evaluation of the acoustic ultrasound and stress wave methods for investigating the mechanical properties of wood and the factors that can affect the results, such as the type of device used, the wood species (Scots pine, Norway spruce, Silver fir), the cardinal direction relative to the direction of the plant growth, and the longitudinal measuring position in the trunk (the height of the trunk). The experiments were done using planks of selected species, with the aim of establishing the extent to which the values of the basic mechanical properties of wood could be predicted. These properties included compression strength parallel to the grain (MORL), modulus of elasticity in compression parallel to the grain (MOEL), modulus of elasticity perpendicular to the grain (MOER), compression strength perpendicular to the grain (MORR), hardness in the particular anatomical directions (HardR, HardT, and HardL), and density.

  • Researchpp 519-529Liu, Y., Li, L., Li, X., Wang, Y., Ren, X., and Liang, J. (2016). "Antibacterial modification of microcrystalline cellulose by grafting copolymerization," BioRes. 11(1), 519-529.AbstractArticlePDF

    Microcrystalline cellulose (MCC) has the advantage of a high specific surface area as compared to that of conventional cellulose fibers. In this study the monomer methacrylamide (MAM) was used to treat MCC by grafting copolymerization. SEM, FTIR, and solid 13C NMR were used to characterize the morphology and composition of MAM-g-MCC. After the chlorination of MAM-g-MCC with 10% sodium hypochlorite solution, the grafted MCC exhibited antibacterial activity as a result of the formation of N-Cl bonds. The thermal stability, antibacterial ability, and storage stability of chlorinated MAM-g-MCC were also studied. The results showed that the chlorinated MAM-g-MCC had excellent storage stability and could inactivate all S. aureus and E. coli O157:H7 within 10 min.

  • Researchpp 530-544Turesson, J., Wang, X., and Gustafsson, A. (2016). "Wall heating - an energy efficient solution for wooden buildings?" BioRes. 11(1), 530-544.AbstractArticlePDF

    Wall heating is an alternative method for residential heating that is used in a limited part of Europe. The goal of this study was to show the feasibility of this method for the Nordic market and to provide a comprehensive picture of wall heating and its functionality compared to traditional methods, i.e. radiators and floor heating. The study was conducted using a literature review, calculations, and a survey. Simulations were made using the computer software EnergyPlus (US Department of Energy). Results showed that placement of wall heating panels in interior walls results in a lower heat loss than placement in outer walls, and that wall heating can have equal or better energy-efficiency compared to floor heating and conventional radiators. Wall heating provides a more comfortable indoor climate, in regard to dust allergies, and there is no need to remove air from each individual heating panel. A disadvantage is the need for hidden installation, which creates a problem for a safe water installation and difficulties in the attachment of fixtures. Also, the wall heating system has difficultly in handling cold drafts. Though wall heating could compete with floor heating and radiators, its disadvantages are sufficient to explain why the system is not yet used in Sweden.

  • Researchpp 545-557Zhang, D., Liu, H., and Sun, L. (2016). "Dynamic analysis of carbon fiber-reinforced wood composites based on finite element model," BioRes. 11(1), 545-557.AbstractArticlePDF

    Carbon fibers were pretreated by ultrasonic agitation and then were used to manufacture carbon fiber-reinforced wood composites (CFRWCs) . The modulus of rupture (MOR) and the modulus of elasticity (MOE) for the CFRWCs were measured. The effects of the compounding pattern and proportion of carbon fiber on the dynamic performance were investigated by dynamic thermomechanical analysis (DMA) and finite element analysis (FEA). Finite element modeling was performed to simulate composite dynamic analysis using ANSYS commercial software. DMA results showed that the critical parameters for the mixed boards appeared to initially increase and then decrease as the content of carbon fiber increased. ANSYS simulations showed that the first-order natural frequency increased for single-sided and two-sided boards as the composite’s carbon fiber content increased, whereas it initially increased and then decreased for mixed boards. In general, the mixed board with 20 wt.% carbon fiber had maximum dynamic performances. ANSYS simulation results were very close to those of the static test, which demonstrated that the finite element model was accurate.

  • Researchpp 558-572Noreen, S., Asgher, M., Hussain, F., and Iqbal, A. (2016). "Performance improvement of Ca-alginate bead cross-linked laccase from Trametes versicolor IBL-04," BioRes. 11(1), 558-572.AbstractArticlePDF

    Extracellular laccase was produced by Trametes versicolor IBL-04 using corn cobs as a substrate under pre-optimized culture conditions. A 64-kDa laccase enzyme was purified and immobilized on calcium alginate beads using glutaraldehyde as a cross-linking reagent. Maximum enzyme immobilization efficiency (89%) was observed with 2-mm calcium-alginate beads that were developed using 4% (w/v) sodium alginate in 2% (w/v) calcium chloride solution. Immobilization of laccase enhanced the optimum temperature but caused an acidic shift in the optimum pH of the enzyme. The immobilized enzyme showed optimum activity at pH 3.0 and 60 °C as compared to pH 4.5 and 45 °C for free laccase. The kinetic constants Km and Vmax of laccase were significantly altered by immobilization. The affinity of enzyme toward its substrate increased (Km decreased), leading to enhanced catalytic efficiency (Vmax increased). Scanning electron microscopy (SEM) was performed to characterize the free and enzyme-bound immobilization matrix. Free and immobilized enzymes also were used for decolorization of the Reactive T Blue dye (030905 GWF) for three days. The free and immobilized laccases decolorized the dye by 65% and 92%, respectively, in 72 h. The immobilized enzyme retained 68% of its original activity after three cycles of repeated reuse for dye decolorization, indicating the usefulness of immobilized laccase in repeated industrial batch operations.

  • Researchpp 573-584Musat, E. C., Salca, E. A., Dinulica, F., Ciobanu, V. D., and Dumitrascu, A. E. (2016). "Evaluation of color variablility of oak veneers for sorting," BioRes. 11(1), 573-584.AbstractArticlePDF

    Veneers are used as overlaying material for various types of composite substrates for the production of veneered panels and furniture. There is a strong correlation between color and quality for the acceptability of a product, which is currently an industrial preoccupation. The aim of the present study was to evaluate the color variability of veneers produced from high-quality European oak logs exhibiting the best production yield. Defect-free logs cut from a Quercus spp. forest in Romania were sliced into veneers. Color measurements were made at various locations on veneer sheets. All data were statistically analyzed. As expected, heartwood highly influenced the final color of decorative oak veneers, in which yellow and red were highlighted. The statistical analysis also revealed the homogeneity of lightness and yellow degree within the veneer collectivity. The color homogeneity within the sectors confirmed the wood quality for veneer production. Therefore, individual veneer sheets can be segregated based on color measurement to provide accurate results for sorting pieces of different colors.

  • Researchpp 585-598Porankiewicz, B., Wieczorek, D., Bocho-Janiszewska, A., and Klimaszewska, E. (2016). "An attempt to analyze the influence of properties of five African wood species on cemented carbide tool wearing," BioRes. 11(1), 585-598.AbstractArticlePDF

    The dulling of cemented carbide cutting tools after milling five African wood species was studied. The wood specimens investigated varied in high temperature corrosivity (HTC), hard mineral contamination (HMC), and density (D). Attempts to replace the combustion method of evaluating the content of natural HMC in wood with spectral mass analysis methods, such as energy dissipative spectrum (EDAX) or atomic absorption spectrometry (AAS), failed. Experiments showed that scanning electron microscope (SEM) analysis of the ash yielded information on the size and shape of small-dimension, natural HMC particles present in the wood specimens. Employing theoretical multi-variable simulation, the combined effects of the HTC, the HMC, and the D on the cemented carbide tool wear was modeled and appeared to be a good explanation of the results observed.

  • Researchpp 599-611Miftieva, E., Gaff, M., Svoboda, T., Babiak, M., Gašparík, M., Ruman, D., and Suchopár, M. (2016). "Effects of selected factors on bending characteristics of beech wood," BioRes. 11(1), 599-611.AbstractArticlePDF

    Wood is a natural raw material that is an integral part of many production processes. By changing the input characteristics of native wood, the qualitative characteristics of the final product can be affected extensively. This article is concerned with examining several factors’ effects (thickness of the material; number of loading cycles) on the bending strength of beech wood during bending in the radial direction. A three-point bending test was used on the sample. The examined properties were investigated on samples of varying thicknesses that were not cyclically loaded, and the results were compared to those acquired from samples that were cyclically loaded. Thirty percent densification of the samples was achieved by rolling. Material fatigue was not achieved as an effect of examined number of cycles, nor did the examined characteristics change as an effect of cyclic loading. Densification of the wood by rolling had no effect on the changes in the examined mechanical properties at the determined level of densification. With an increase in the material’s thickness, the values of the examined characteristics decreased, which was caused by the fact that the increase in the cross-sectional modulus of the material was greater than the increase of the affecting force.

  • Researchpp 612-625Reyes, P., Márquez, N., Troncoso, E., Parra, C., Mendonça, R. T., and Rodríguez, J. (2016). "Evaluation of combined dilute acid-kraft and steam explosion-kraft processes as pretreatment for enzymatic hydrolysis of Pinus radiata wood chips," BioRes. 11(1), 612-625.AbstractArticlePDF

    The combination of hemicellulose pre-hydrolysis by dilute acid or steam-explosion followed by kraft pulping was one approach evaluated in this work to generate pulps from radiata pine wood chips amenable to saccharification by enzymatic hydrolysis. Dilute acid (combined severity factor, CS = 1.67) and steam explosion (severity factor, log Ro = 4.09) treatments were able to solubilize approximately 53% and 63% of the original hemicelluloses content in wood, respectively. Extracted wood chips were subjected to kraft cooking (170 °C, 16-18% active alkali, 30% sulfidity and 1200 H-factor) to produce pulps that were further saccharified by cellulases. Lignin removal increased with increasing active alkali, affording delignification levels 28% for dilute acid and 68% for steam explosion extraction pretreatment pulps. Enzymatic digestibility of P. radiata pulps were low, and only samples pretreated by steam explosion reached glucan-to-glucose conversion near to 75%; this treatment was 31% and 37% higher than that obtained with wood chips that were pretreated by dilute acid extraction.

  • Researchpp 626-633Wang, Z., Zhou, J., Gong, M., Chui, Y. H., and Lu, X. (2016). "Evaluation of modulus of elasticity of laminated strand lumber by non-destructive evaluation technique," BioRes. 11(1), 626-633.AbstractArticlePDF

    Non-destructive evaluation (NDE) techniques have been shown to be effective for evaluating mechanical properties of wood-based materials. In this study, transverse vibration of a beam under the two ends free boundary condition (FBV) was employed to measure the modulus of elasticity (MOE) in different strength directions of laminated strand lumber (LSL). It was found that the MOE values measured by the FBV were slightly higher than those measured using the three-point bending test (TPB), and the correlation coefficients between the MOE values along the major and minor strength directions measured by the two methods were 0.845 and 0.938, respectively. The effect of the length/depth ratio on measured MOE values by the FBV method was also investigated. With the decrease in the length/depth ratio of LSL, the measured MOE in the major and minor strength directions decreased. The results of the ANOVA test showed that the length/depth ratios had a significant effect on the measured MOE. The experimental values of MOE of LSL in the diagonal strength direction matched well with the theoretical values calculated by the Hankinson-type formula.

  • Researchpp 634-650Lou, B., Xiong, Y., Li, M., Ni, J., Wang, X., and Ma, K. (2016). "nOx emission model for the grate firing of biomass fuel," BioRes. 11(1), 634-650.AbstractArticlePDF

    Establishing an appropriate NOX production and decomposition model is of practical significance to the grate firing of biomass fuel. This study used the CHEMKIN software package to simulate the combustion process of biomass pyrolysis and char combustion. Through rate of production (ROP) analysis and simplification based on GRI-Mech3.0, the 15-step reaction mechanism of volatile-N converting into NOX and the 12-step reaction mechanism of char-N converting into NOX were specified. It was found that in the NOX generated from the fuel, N was mainly in the form of NO and N2O. HCN and NH3 were the important intermediate products. NH3 was mainly converted into NO and some converted into N2O, while HCN mainly consumed NO and produced N2O. According to the transfer characteristics of the biomass fuel nitrogen, the NOX production and decomposition model of the biomass fuel nitrogen in grate furnace firing was established. A simulation computation on the NOX production was implemented for an actual furnace. The established model was confirmed reliable through the comparison of field test data and simulation results.

  • Researchpp 651-662Han, L., Zhao, X., Zhou, H., and Luo, X. (2016). "Comparison between allowable properties method and reliability analysis method to determine design values of visually graded Chinese larch 40 x 65 mm lumber," BioRes. 11(1), 651-662.AbstractArticlePDF

    The reliability analysis method and the allowable stress method were both applied in this study to determine design values of ultimate compression strength (UCS) of visually-graded 40 x 65 mm dimension Chinese larch lumber. A total of 784 lumber samples were tested on the static full-size compression strength, according to Chinese National Standards. The goodness-of-fit for the UCS distribution of four visual grades of lumber were analyzed, and first-order, second-moment reliability analyses under different load cases were performed based on all of the test data. The log-normal distribution was found to optimize the fitted distribution of the ultimate compression strength of Chinese larch dimension lumber. Design values of the compression strength of grades Ic, IIc, IIIc, and IVc were suggested to have the minimum reliability index of 3.2 for the reliability analysis method, and the reduction factor of 1/1.9 for the allowable stress method. The results showed that the design values in the Chinese Code were the most conservative for high visual grade dimension lumber compared to the reliability analysis and allowable stress methods. The reliability analysis method was more suitable for developing design values of lower visually-graded lumber.

  • Researchpp 663-673Chen, J., Liu, C., and Wu, S. B. (2016). "Catalytic fast pyrolysis of Alcell lignin with nano-NiO," BioRes. 11(1), 663-673.AbstractArticlePDF

    Catalytic fast pyrolysis of Alcell lignin with various additive ratios (5%, 10%, and 15%, mass ratio) of nano-NiO was investigated using a horizontal pyrolyzer. Characterization methods, including Fourier transform infrared spectroscopy (FTIR), gas chromatography (GC), gas chromatography coupled with mass spectrometry (GC/MS), and elemental analysis, were utilized to identify the catalytic fast pyrolysis products. The results indicated that the nano-NiO catalyst had remarkable effects on the yield and quality of these products. The formation of gases, especially CO, CO2, and CH4, were greatly promoted when the additive ratio increased, while the formation of bio-char was clearly inhibited. However, when the additive ratio was 10%, the maximum yield of bio-oil (53.09 wt.%) was obtained, and the corresponding maximum higher heating value (HHV) was 25.33 MJ/kg. Furthermore, nano-NiO caused a large variation in the species of the compounds in bio-oil. Operating with the optimal nano-NiO additive ratio (10%), the carbon conversion rate was 65.50%, and the energy conversion rate was 74.53%.

  • Researchpp 674-695Faseleh Jahromi, M., Liang, J. B., Abdullah, N., Goh, Y. M., Ebrahimi, R., and Shokryazdan, P. (2016). "Extraction and characterization of oligosaccharides from palm kernel cake as prebiotic," BioRes. 11(1), 674-695.AbstractArticlePDF

    The main objective of the present study was to extract and characterize oligosaccharides from palm kernel cake (OligoPKC) to be used as a prebiotic. Up to 16.81% of oligosaccharides were extracted from PKC using neutral detergent solution with two to eight degrees of polymerization. Molecular weights of seven fractions of OligoPKC were estimated using a mass spectrophotometer procedure resembling those of mannobiose, mannotriose, mannotetraose, mannopentaose, and mannohexaose standards, while those of two unknown components resembled those of heptasaccharide and octasaccharide. Enzymatic hydrolysis of OligoPKC using 11 enzymes showed that β-mannosidase and β-mannanase had the highest effects. OligoPKC fractions were potential substrates for growth of four species of Lactobacillus. Supplementation of OligoPKC in the diet of broiler chickens increased the population of beneficial microbes. However, it reduced the populations of pathogenic bacteria in the cecum. Hence, OligoPKC can be considered a potential prebiotic supplement in the feed and food industry.

  • Researchpp 696-712Pei, Y., Wang, S., Qin, C., Su, J., Nie, S., and Song, X. (2016). "Optimization of laccase-aided chlorine dioxide bleaching of bagasse pulp," BioRes. 11(1), 696-712.AbstractArticlePDF

    The laccase-mediator system in laccase-aided chlorine dioxide bleaching of bagasse pulp was optimized using response surface methodology (RSM). The effects and interactions of the laccase enzyme dosage, the dosage of the mediator 1-hydroxybenzotriazole (HBT), and the reaction time on the adsorbed organic halogen (AOX) content of the wastewater as well as the brightness and kappa number of the pulp were examined. The optimal reaction conditions to achieve a balance of lower AOX content, higher brightness, and lower kappa number were as follows: laccase enzyme dosage of 20.3 U/g, HBT dosage of 1.51%, and reaction time of 154.5 min. Under these conditions, an AOX content of 20.67 mg/L, brightness of 58.94% ISO, and kappa number of 2.71 were observed. These results will offer a favorable option for pulp and paper mills as well as the natural environment and therefore provide a theoretical foundation for the industrial application of laccase in bleaching processes.

  • Researchpp 713-723Nie, S., Yao, S., Wang, S., and Qin, C. (2016). "Absorbable organic halide (AOX) reduction in elemental chlorine-free (ECF) bleaching of bagasse pulp from the addition of sodium sulphide," BioRes. 11(1), 713-723.AbstractArticlePDF

    A laboratory investigation was developed to confirm and to quantify the reductions in absorbable organic halide (AOX) discharge when sodium sulphide was added during elemental chlorine-free (ECF) bleaching of sugarcane bagasse pulp. After the chlorine dioxide bleaching stage, the pulp was sent directly into the extraction stage without washing. FTIR was employed to determine the breakage of chemical bonds in the pulp, and GC-MS was used to measure the composition of the bleaching effluent. The addition of sodium sulphide caused a reduction in AOX of up to 46.7%. The AOX reduction reached this maximum when the sodium sulphide was added 30 min after the start of the extraction stage and when the pH was higher than 12. FTIR spectroscopy showed that the phenolic lignin of the pulp was degraded by the sodium sulphide and that the syringyl lignin and C-O-C, C=O structure of the pulp holocellulose of the pulp was preserved during the extraction stage. The GC-MS showed that the chlorobenzene and chlorophenol contents decreased noticeably after the addition of sodium sulphide.

  • Researchpp 724-735Pan, Y., Wang, X., and Huang, J. (2016). "The preparation, characterization, and influence of multiple electroless nickel-phosphorus (Ni-P) composite coatings on poplar veneer," BioRes. 11(1), 724-735.AbstractArticlePDF

    Nickel-Phosphorus (Ni-P) composite coatings were prepared on a poplar veneer surface via a simple electroless nickel (Ni) approach. The substrate deformation, flatness, crystalline structure, and wear resistance of the Ni-P composite coatings were investigated. The deformation degree of the substrate decreased as the number of deposition steps was increased. The flatness and wear resistance of the composite coatings were enhanced with the increase in the number of depositions. The full width, at half of the maximum values of Ni X-ray diffraction (XRD), of peaks in the composite coatings were broadened and strengthened with an increment of the number of depositions in the coatings. The XRD patterns revealed that the Ni that had been deposited on poplar veneer had a crystallite size structure between 42 and 88 Å. The composite structure was characterized with scanning electron microscopy (SEM) images. The uniformity of the particles in the composite coatings could be improved with the increase in the number of depositions. The wear resistance of ideal coatings with a homogeneous thickness was measured via the rolling wear testing machine (RWTM), and the wear resistance of the coatings was increased by 200% compared with that of coatings obtained via a single deposition.

  • Researchpp 736-747Kubš, J., Gaff, M., and Barcík, Š. (2016). "Factors affecting the consumption of energy during the milling of thermally modified and unmodified beech wood," BioRes. 11(1), 736-747.AbstractArticlePDF

    This paper deals with an analysis of the energy efficiency of the milling of thermally modified and unmodified beech wood, taking into consideration the angular geometry of the cutting tool (milling cutter). The analysis was made using the METREL Power Q plus MI2392 device to measure the cutting power of the machine during milling with predetermined technical and technological cutter settings. The results were compared with respect to electricity savings in industrial production. The electrical power of the milling cutter, when machining thermally modified wood, was 5% less on average compared with the machining of unmodified wood under identical technological conditions.

  • Researchpp 748-758Nemati, M., Eslam, H. K., Talaeipour, M., Bazyar, B., and Samariha, A. (2016). "Effect of nanoclay on flammability behavior and morphology of nanocomposites from wood flour and polystyrene materials," BioRes. 11(1), 748-758.AbstractArticlePDF

    The flammability behavior of wood/plastic nanocomposites made from recycled polystyrene, wood flour, and nanoclay were investigated in this study. The wood flour was mixed, using the two weight ratios of 40 wt.% and 60 wt.% with recycled polystyrene, and nanoclay was added at 0 wt.% and 5 wt.%. A coupling agent was also added at up to 3 wt.% of the composite. The results showed that the oxygen index increased when higher contents of wood flour were added. Furthermore, it was found that the samples required more oxygen for ignition when the percentage of wood flour was increased. Similarly, it was found that the samples required a greater amount of oxygen for ignition with increasing nanoclay content. Therefore, the flammability of the sample decreased because the time to ignition took longer in the absence of sufficient oxygenation. X-ray analysis of the nanocomposites revealed that the morphological structure involved intercalation.

  • Researchpp 759-771Chen, H., Wang, C., Ye, J., Zhou, H., and Tao, R. (2016). "Isolation of sulfuretin and butin from Rhus verniciflua Stokes using medium-pressure liquid chromatography and their tyrosinase inhibitory effects," BioRes. 11(1), 759-771AbstractArticlePDF

    The aim of this study was to separate antityrosinase compounds of the ethyl acetate fraction from Rhusverniciflua Stokes using medium pressure liquid chromatography. Among the different fractions, the Fr.6 fraction showed the highest antityrosinase capacity (96.5%), followed by the Fr.5 fraction (85.6%). The Fr.1 fraction showed the lowest antityrosinase capacity (12.4%). Bioactivity-guided fractionation of Fr.5.5 and Fr.6.4 led to the isolation and identification of butin and sulfuretin. Then the inhibitory effects of butin and sulfuretin on the monophenolase and diphenolase activity of mushroom tyrosinase were investigated. The results showed that butin and sulfuretin can act as potent inhibitors of monophenolase and diphenolase activities of the enzyme, and the IC50 of the butin and sulfuretin were 16.0 μmol/L and 13.64 μmol/L, respectively. The lag period of the enzyme was obviously lengthened; it was estimated to be 1 min in the absence of inhibitor, extended to 26 min in the presence of 185 μmol/L of butin, and 6 min in the presence of 111.1 μmol/L of sulfuretin. A kinetic analysis showed that butin and sulfuretin are competitive inhibitors. The results revealed that the butin and sulfuretin took up the loci of the substrate combined with enzyme, or blocked the anionic initiation by eliminating free radicals, thus weakening the catalytic reaction of oxidation of L-dopa.

  • Researchpp 772-785Huang, L., Xia, P., Liu, Y., Fu, Y., Jiang, Y., Liu, S., and Wang, X. (2016). "Production of biodegradable board using rape straw and analysis of mechanical properties," BioRes. 11(1), 772-785.AbstractArticlePDF

    This study investigated the glueless preparation of biomass board using rape straw on a laboratory scale. The board-making process was broken down into four steps: soaking, refining, shape recovery, and hot-pressing. To observe the effect of pressure during the hot-press stage on the strength of the bio-board, five panels were manufactured at various pressures. Moreover, density functional theory (DFT) was used to explore how varying the pressure influenced the strength properties of the board. As pressure increased, the density of these five panels changed from 0.95 to 1.12 g/cm3. The mechanical tests showed that the bending rupture strength of these panels changed from 43 to 53 MPa, while the tensile rupture strength changed from 27 to 33 MPa. The bending strength of these biomass boards performed well enough to qualify them as Type-35 board, and their density classified them as hardboard, according to the Japanese industrial standards (JIS). This study showed that board-making was feasible using rape straw. The experimental results and the density functional theory results were consistent, in that the mechanical properties of the panels improved with increasing pressure. The DFT method was shown to be useful in exploring the factors that influenced the strength properties of the biomass board on the microscopic scale.

  • Researchpp 786-799Ling, Z., Ji, Z., Ding, D., Cao, J., and Xu, F. (2016). "Microstructural and topochemical characterization of thermally modified poplar (Populus cathayaha) cell wall," BioRes. 11(1), 786-799.AbstractArticlePDF

    Although many studies have been conducted on the wood property and chemical changes caused by thermal modification, little has been reported on the microstructural and topochemical changes occurring in the cell wall during heat treatment. In this study, poplar (Populus cathayaha) was treated within a temperature range from 180 to 220 °C for 4 h. Chemical analyses by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) indicated that heat treatment resulted in deacetylation of hemicelluloses and cleavage of lignin chains, thus generating new carbonyl and phenolic linkages. Transformation of matrix substances contributed to microstructural changes that appeared in clearly distorted and collapsed fiber and vessel walls along with the delamination of compound middle lamella (CML) and secondary walls (S), which showed a reduced capability to resist deformation. It was also observed by fluorescence microscopy (FM) and scanning electron microscope coupled with energy dispersive X-ray analysis (SEM-EDXA) that the concentration of lignin increased, probably because of the degradation of hemicelluloses and the generation of new carbonyl groups. These results on cell wall microstructure and topochemistry can help explain the altered wood properties revealed by dynamic mechanical analysis (DMA) and equilibrium moisture content (EMC) testing after heat treatment.

  • Researchpp 800-810Kubojima, Y., Kato, H., Tonosaki, M., and Sonoda, S. (2016). "Measuring Young's modulus of a wooden bar using flexural vibration without measuring its weight," BioRes. 11(1), 800-810.AbstractArticlePDF

    This study aimed to develop a simple measuring method to determine Young’s modulus of a wooden bar by measuring its flexural vibration without measuring its weight. Before and after bonding an iron piece to a wooden rectangular bar, a free-free flexural vibration test and fixed-fixed flexural vibration test were performed to obtain Young’s modulus. Young’s modulus was calculated by substituting the ratio of the resonance frequencies of a wooden bar with and without a bonded iron piece into the frequency equation. The calculated results resembled the experimental values determined without the iron piece.

  • Researchpp 811-818Gu, Z., Zhang, X., and Xu, K. (2016). "Die hole parameters vs. biomass briquette properties," BioRes. 11(1), 811-818.AbstractArticlePDF

    Circular moulds, which have multiple holes, are key components of biomass briquetting machines. The configuration parameters of the die holes determine the strength and the service life of the circular moulds. Special testing moulds were designed for this research, and the strain values of the specific points were detected using strain-gauge transducers. Then, the mechanical data of the points, including the positive pressures and the friction and distribution values, were calculated. Mechanical models were established to explore the stress change of the die holes by altering the rheological properties of the straw. In addition, the mechanical models provided the theoretical principles for analyzing their influence on biomass solidification by changing the forming pressure of the die holes during the biomass briquetting process.

  • Researchpp 819-826Qiao, J., Wang, A., and Li, X. (2016). "Preparation and performance of wheat-straw composite board with inorganic adhesive," BioRes. 11(1), 819-826.AbstractArticlePDF

    With wheat-straw and inorganic binder as the major raw materials, inorganic wheat-straw composite board was manufactured by mold-pressing. The effect of wheat-straw loading on the physical and mechanical properties of inorganic wheat-straw composite board was studied. X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were used to characterize and evaluate the performance of the resulting composite board. Results showed that the optimal glue-straw ratio was 2.1. With the increase in glue-straw ratio during board maintenance, the inhibition effect was weaker during hydration reaction of inorganic materials. This accelerated the process of the hydration reaction in inorganic wheat-straw composite board such that the reaction was carried out more completely and produced more complete crystallization and more inorganic glue. Internal bond strength (IB) and thermal stability of inorganic wheat-straw composite board increased gradually, while TS decreased. Modulus of rupture (MOR) and modulus of elasticity (MOE) firstly increased and then decreased. In summary, the bonding interface between wheat-straw and inorganic adhesive performed well.

  • Researchpp 827-838Jin, F., Jiang, Z., and Wu, Q. (2016). "Creep behavior of wood plasticized by moisture and temperature," BioRes. 11(1), 827-838.AbstractArticlePDF

    Moisture in wood acting as a plasticizer will strongly affect the wood’s viscoelastic properties. However, achieving the desired moisture content (MC) at elevated temperatures during creep tests is difficult. The aim of this study is to accurately and systematically investigate the creep behavior of birch wood at high temperatures. Experiments were conducted using a dynamic mechanical analyzer with a relative humidity accessory coupled with polyvinylidene chloride (PVDC) film for wrapping samples. Creep behavior was examined at six MCs (0%, 6%, 12%, 18%, 24%, >30%) and 11 temperatures (5 to 105 °C). The MC of wood was strictly and accurately controlled during creep tests. Instantaneous compliance (IC) and creep compliance (CC) increased with the increase of both temperature and MC, with significant changes at higher temperatures and MCs. The effects on IC and CC were more pronounced when the subject was influenced by MC, with readings approximately three times and one time greater than those influenced by temperature, respectively. Dramatic increases in CC were found at certain temperatures and MC values. There was a complex interaction between temperature and MC on IC and CC.

  • Researchpp 839-849Yamada, H., Miyafuji, H., Ohno, H., and Yamada, T. (2016). "A simple method for separating lignin and carbohydrates from softwood biomass in a glass tube using tetra-n-butylphosphonium hydroxide," BioRes. 11(1), 839-849AbstractArticlePDF

    The dissolving properties of softwood in an aqueous solution of the ionic liquid tetra-n-butylphosphonium hydroxide ([P4,4,4,4]OH) were studied. Cedar wood meal and 40% [P4,4,4,4]OH aqueous solution were mixed in a glass tube and treated at 121 °C and 2 atm in an ordinary autoclave. As the treatment time increased, the residue content decreased to 68.7%, 49.4%, and 37.0% after 1, 5, and 20 h, respectively. Following the 20-h treatment time, 97.0% of the residue was determined to be holocellulose and 96.3% of the constituent monosaccharide in the residue was glucose. UV analysis showed that most of the lignin had dissolved in the [P4,4,4,4]OH solution. Phenolic hydroxyl group analysis of the dissolved lignin suggested that the macromolecular structures of the lignin were considerably degraded. The results of this study suggest the possibility of developing a simple multi-sample analysis method for lignin content using a single-step autoclave treatment in a glass tube using an aqueous solution of [P4,4,4,4]OH.

  • Researchpp 850-860He, Q., Shi, H., Gu, H., Naka, G., Ding, H., Li, X., Zhang, Y., Hu, B., and Wang, F. (2016). "Immobilization of Rhizopus oryzae LY6 onto loofah sponge as a whole-cell biocatalyst for biodiesel production," BioRes. 11(1), 850-860.AbstractArticlePDF

    Whole cell biocatalysts for biodiesel production have garnered significant attention in recent years, as they can help avoid the complex procedures of isolation, purification, and immobilization of extracellular lipase. Because of its renewability and biodegradability, loofah (Luffa cylindrica) sponge is an advantageous substitute for traditional biomass carriers in whole cell immobilization. Rhizopus oryzae mycelia can spontaneously attach onto loofah sponge particles (LSPs) during cell cultivation. The highest immobilized R. oryzae cells concentration can reach up to 1.40 g/1 g of LSPs. The effects of biocatalyst addition and water content on methanolysis for biodiesel production were investigated in this paper. The operational stability of glutaraldehyde-treated biocatalyst at 35 °C, using a 1:1 oil-to-methanol ratio, was assayed, revealing a 3.4-fold increase in half-life compared with the untreated biocatalyst. Under optimized conditions, the yield of methyl esters in the reaction mixture reached 82.2% to 92.2% in each cycle. These results suggested that loofah sponge is a potential fungi carrier for an immobilized whole-cell biocatalyst.

  • Researchpp 861-872Eng, C. C., Ibrahim, N. A., Zainuddin, N., Ariffin, H., and Wan Yunus, W. M. Z. (2016). "Chemical modification of oil palm mesocarp fiber by methacrylate silane: Effects on morphology, mechanical, and dynamic mechanical properties of biodegradable hybrid composites," BioRes. 11(1), 861-872.AbstractArticlePDF

    Effects of modifying oil palm mesocarp fibers (OPMF) by methacrylate silane on polylactic acid (PLA)/ polycaprolactone (PCL)/clay/OPMF hybrid composites were investigated. The composites were prepared by a melt blending technique and characterized by dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The silane-treated OPMF hybrid composites showed better tensile strength, tensile modulus, and elongation at break than unmodified OPMF hybrid composites. DMA analysis showed an increase in storage modulus when silane-treated OPMF was added to a hybrid composite. The loss modulus curve showed that the incorporation of silane-treated OPMF into a hybrid composite shifted the two glass transition temperatures (Tg) of composites closer to each other. The low tan δ peak indicated good fiber/matrix adhesion for the silane-treated OPMF hybrid composites. SEM micrographs revealed that silane-treated OPMF hybrid composites showed better fiber/matrix adhesion than unmodified OPMF hybrid composites because of absence of gap between silane-treated OPMF and the matrix in the composite.

  • Researchpp 873-885Zailuddin, N. L. I., Husseinsyah, S., Hahary, F. N., and Ismail, H. (2016). "Treatment of oil palm empty fruit bunch regenerated cellulose biocomposite films using methacrylic acid," BioRes. 11(1), 873-885.AbstractArticlePDF

    Regenerated cellulose (RC) biocomposite films from oil palm empty fruit bunch (OPEFB) and microcrystalline cellulose (MCC) were prepared using ionic liquid. N,N-Dimethylacetamide (DMAc) and Lithium Chloride (LiCl) were used to dissolve the regenerated cellulose at room temperature. The effects of OPEFB content and chemical modification using methacrylic acid (MAA) on the X-ray diffraction, tensile properties, morphology, thermal properties, and Fourier transform infrared spectroscopy (FTIR) results for RC biocomposite films were investigated. The chemical modification of OPEFB using MAA enhanced the properties of the treated RC biocomposite films. At 2 wt.% of OPEFB both of the RC biocomposite films showed the highest crystallinity index, tensile strength, modulus of elasticity, and thermal stability. The treated RC biocomposite films had a higher crystallinity index, tensile strength, modulus of elasticity, and thermal properties than the untreated RC biocomposite films. The Tdmax of treated RC biocomposite films with MAA was higher than that of untreated RC biocomposite films. This indicates that treated biocomposite films had higher thermal stability. The enhancement of interfacial interaction and the dispersion of treated RC biocomposite films with MAA were revealed by scanning electron microscopy (SEM). The FTIR spectra of treated RC biocomposite films indicated interaction between cellulose from OPEFB and MCC with MAA.

  • Researchpp 886-898Hahary, F. N., Husseinsyah, S., and Zakaria, M. M. (2016). "Improved properties of coconut shell regenerated cellulose biocomposite films using butyl methacrylate," BioRes. 11(1), 886-898.AbstractArticlePDF

    Butyl methacrylate acid (BMA) was used to enhance the properties of coconut shell (CS) and regenerated cellulose (RC) biocomposite films. The effects of coconut shell content and BMA on the tensile properties, crystallinity index (CrI), thermal properties, and morphology of biocomposite films were investigated. An increase in CS content, up to 3 wt.%, increased the tensile strength and modulus of elasticity, but decreased the elongation at break. The CS-RC biocomposite films treated with BMA exhibited higher tensile strength and modulus of elasticity but lower elongation at break. The crystallinity index (CrI) and thermal stability of CS-RC biocomposite films increased with increasing CS up to 3 wt.%. Treated CS biocomposite films had better thermal stability than untreated CS biocomposite films. The presence of BMA increased the crystallinity of CS regenerated cellulose biocomposite films. Enhancement of the interfacial interaction of CS-RC biocomposite films was revealed by morphological study.

  • Researchpp 899-912Wang, Q., Shen, F., Yang, G., Zhang, Y., Deng, S., Hu, Y., Zhang, J., Song, C., and Zeng, Y. (2016). "Pretreating luffa sponge (Luffa cylindrica L.) with concentrated phosphoric acid and subsequent enzymatic saccharification," BioRes. 11(1), 899-912.AbstractArticlePDF

    Luffa was evaluated as a potential energy crop. A considerable amount of luffa sponge biomass can be grown in a vertical direction with approximately 70% polysaccharide content and low lignin content. When concentrated H3PO4 was employed to pretreat luffa sponge, hemicelluloses were the most sensitive component, followed by cellulose and lignin. Hemicellulose solubilization and cellulose loss positively responded to the elevated temperature, time, H3PO4 concentration, and dosage for pretreatment. However, lignin solubilization was not affected greatly. Although the initial hydrolysis rate was accelerated by increasing pretreatment temperature, the final glucose conversion was reduced as temperature was raised higher than 50 °C. Prolonging pretreatment time was positively correlated to enzymatic digestibility. When H3PO4 concentration was lower than 80%, the final glucose conversion was increased with increasing H3PO4 concentration. Increasing H3PO4 concentration to 84% for pretreatment caused the final glucose conversion to decrease slightly, although the hydrolysis rate was initially accelerated. Additionally, an improvement of glucose conversion was obtained with increasing the substrate-to-phosphoric acid ratio. However, the improvement was not cost-effective, as the ratio was lower than 1-to-8.

  • Researchpp 913-928Choh, J. L., Ching, Y. C., Gan, S. N., Rozali, S., and Julai, S. (2016). "Effects of oil palm empty fruit bunch fiber on electrical and mechanical properties of conductive filler reinforced polymer composite," BioRes. 11(1), 913-928.AbstractArticlePDF

    Low density polyethylene (LDPE), carbon black (CB), and oil palm empty fruit bunch (OPEFB) fiber composites were prepared by melt blending and compression molded into sheets. The effects of incorporated fibers on the electrical conductivity, thermal conductivity, tensile properties, and thermal degradation of the composites were investigated. FTIR results suggest that the OPEFB fibers interact poorly with the polymer matrix and lead to a decrease in mechanical properties. The electrical conductivity of the composites decreased with increasing OPEFB fiber content. Despite the slight decline in conductivity, the composites still were sufficiently conductive relative to applications such as sensors and electromagnetic shielding after the fiber addition. Reduction in thermal conductivity by as much as 10.9% was observed with the addition of 20% OPEFB fiber into LDPE/CB composites. The thermal stability of LDPE/CB/OPEFB fiber composites decreased with increasing fiber content because of the low thermal stability of the incorporated natural fiber.

  • Researchpp 929-943Li, H., Deeks, A. J., Zhang, Q., and Wu, G. (2016). "Flexural performance of laminated bamboo lumber beams," BioRes. 11(1), 929-943.AbstractArticlePDF

    This study investigated the flexural performance of 20 laminated bamboo beam specimens. The load-strain and load-displacement relationships were obtained from tests, and the detailed failure modes, bending strength, and elastic modulus for all specimens are reported. The study demonstrates the following points: all the beams displayed an initial elastic phase, non-linear deformation, and then brittle failure initiated by rupture on the tension side of the beam. The elastic moduli for compression and tension of the laminated bamboo were the same, and the strain was distributed linearly across the cross-section of the beams during the testing process. There were no obvious width effects on the ultimate strain or bending strength of the laminated bamboo beam. A tri-linear constitutive model is proposed to represent the behaviour of the laminated bamboo under bending, which is shown to reproduce the load-strain and load-displacement responses of the beams very well. In addition, a calculation formula for the ultimate bending moment is proposed.

  • Researchpp 944-956Wang, X., Hagman, O., Sundqvist, B., Ormarsson, S., Wan, H., and Niemz, P. (2016). "Shear strength of Scots pine wood and glued joints in a cold climate," BioRes. 11(1), 944-956.AbstractArticlePDF

    The impact of cold temperatures on the shear strength of Scots pine (Pinus sylvestris) joints glued with seven commercially available adhesives was studied in this work. The cold temperatures investigated were: 20, −20, −30, −40, and −50 °C. Generally, within the temperature test range, the shear strength of Scots pine solid wood and wood joints were more resistant to the effect of temperature than those of Norway spruce. As the temperature decreased, only some of the joints’ shear strength significantly decreased. In most cases, PUR adhesive yielded the strongest shear strength and MUF adhesive yielded the weakest shear strength. MF adhesive responded to temperature changes in a similar manner to that of PUR and PVAc adhesives. The shear strengths of wood joints with PRF and EPI adhesives were more sensitive to temperature change. For dynamic tests of shear strength, the values for 12-h and 6-day tests under temperature cycles (−20 and 0 °C) were compared. The values for 6-day tests were lower than those for 12-h tests. Therefore, the duration of the samples subjected to the same temperature had a significant impact on shear strength. Our results indicate that PUR adhesive is the most stable; whereas the stability of MUF and PRF adhesives decreased significantly.

  • Researchpp 957-964Fan, W., Wang, X., Liu, J., and Xu, B. (2016). "Surface modification of ground calcium carbonate with starch, sodium stearate, and hexametaphosphate," BioRes. 11(1), 957-964.AbstractArticlePDF

    Ground calcium carbonate (GCC) was modified by starch with the aid of sodium stearate and sodium hexametaphosphate. The GCC was encapsulated within the complex. The effect of the dosages of sodium stearate and sodium hexametaphosphate on the coating weight of modified GCC and the complex utilization rate were studied. The SEM images of modified GCC were compared with that of unmodified GCC. The results showed that the dosage of these two modifiers affected the coating weight of modified GCC and the complex utilization rate.

  • Researchpp 965-983Cardona, F., and Sultan, M. T. H. (2016). "Characterization of environmentally sustainable resole phenolic resins synthesized with plant-based bioresources," BioRes. 11(1), 965-983.AbstractArticlePDF

    “Green” resole phenolic resins for laminating applications were synthesized, and their properties and thermal stability were determined. The plant-based cardanol and condensed tannin were used as the partial substitutes of up to 40% of the phenol in the synthesis of the phenolic resins. The resins were synthesized with different proportions of phenol (P) to cardanol (C) and with different total molar ratio to the formaldehyde (F) in the resins (1.25 to 2.0). An increased cardanol content resulted in a proportional increase in the flexibility and fracture toughness of the cured cardanol-phenol-formaldehyde (CPF) resins. Also, a direct proportionality was found between increasing cardanol content and decreased crosslink density of the CPF resins. The best results were obtained with the formulation with a P:F molar ratio equal to 1:1.25. Tannin was incorporated into the CPF resins and the fracture toughness and flexibility values of the cured Tannin-CPF resins were found to be proportional to and increasing with the tannin content. However, glass transition temperature (Tg), flexural stress, and flexural modulus values of the CPF resins decreased with the tannin content. TGA-FTIR study of the resins was carried out and the emitted gas species during the pyrolysis of the samples were identified. The thermal stability and the temperature of degradation of the cured CPF resins decreased with increasing cardanol content.

  • Researchpp 984-995Parobek, J., Paluš, H., Kalamárová, M., Loučanová, E., Šupín, M., Križanová, A., and Repková Štofková, K. (2016). "Energy utilization of renewable resources in the European Union - Cluster analysis approach," BioRes. 11(1), 984-995.AbstractArticlePDF

    This paper analyzes and evaluates the European Union (EU) utilization of renewable resources in energy production and consumption. Biomass and renewable waste, with a share of 64.2% of primary renewable energy production, is the most important energy source in the EU. However, utilization of renewables in energy production and consumption differs across EU countries and is significantly influenced by various factors, including environmental, social, and economic characteristics. Cluster analysis was used to reveal these differences based on the identification and quantification of a set of factors reflecting the availability of renewable resources, utilization of renewable resources, and relevant socio-economic indicators. The results indicate that there are nine main identifiable clusters, considering the high variability of selected variables. The analysis confirmed that the economically developed EU countries with significant renewable resources have above-average primary energy production from renewable resources and biomass in particular. On the other hand, small EU countries are aggregated in numerous clusters characterized by under-average values in terms of availability and utilization of renewable resources such as wood production or energy consumption but with a relatively high share of renewable energy in gross final energy consumption.

  • Researchpp 996-1006Yao, S., Gao, C., Zhu, H., Zhang, Y., Wang, S., and Qin, C. (2016). "Effects of additives on absorbable organic halide reduction in elemental chlorine-free bleaching of bagasse kraft pulp," BioRes. 11(1), 996-1006.AbstractArticlePDF

    In order to further reduce absorbable organic halide (AOX) formation in the bleaching effluent, NH2SO3H and DMSO were added during the elemental chlorine-free (ECF) bleaching (D0EpD1) of bagasse kraft pulp. In the D0 stage, AOX formation decreased by 10% with 0.1% NH2SO3H, and a reduction of 11.2% with 1.0% DMSO, respectively. Ultraviolet (UV) spectra, Fourier transform infrared spectroscopy (FTIR), and gas chromatography-mass spectroscopy (GC-MS) were adopted in characterizing changes of lignin degradation and the main functional groups of bleached pulp. The UV spectrum showed that the quantity of polyphenols decreased after adding the additives. The FTIR spectrum showed that both the content of phenolic-type lignin and the degradation degree of lilac-type lignin decreased after adding NH2SO3H. If was found that DMSO was beneficial in retaining C-O-C and C=O structures in cellulose and hemicellulose, while NH2SO3H decreased the content of β-glycosidic bonds and C-O-C structures in cellulose and hemicellulose. The composition of lignin degradation products in the bleaching effluent was analyzed by GC-MS. The contents of chlorobenzene and chlorophenol decreased notably when additives were added. Compared with DMSO, NH2SO3H exhibited poor inhibition on the formation of some phenols.

  • Researchpp 1007-1014Tang, Z., Shi, C., Wu, S., Jiang, Z., and Wang, L. (2016). "Fabrication of hydrophobic surface on wood veneer via electroless nickel plating combined with chemical corrosion," BioRes. 11(1), 1007-1014.AbstractArticlePDF

    Birch veneers were coated with Ni-P films by a combined process of KBH4 activation and electroless plating. The plated veneers were further chemically corroded to obtain hydrophobic surfaces on wood. The effect of chemical corrosion on the contact angle of the veneers was investigated. The hydrophobic veneers were characterized by X-ray photo electron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The surface contact angle of birch veneer before and after it was plated with Ni-P alloy coating was 41º and 121º, respectively. The contact angle reached 136.7º when the nickel-coated veneers were corroded in CuSO4 aqueous solution for 30 min. XPS analysis showed that Cu0 cluster doped with little CuO formed on the corroded surface of Ni-P alloy film after chemical corrosion. SEM and XRD showed that rough copper clusters formed on the surface of the wood veneer and revealed the reason of the surface hydrophobicity. This study provides a new pathway for fabricating hydrophobic wood.

  • Researchpp 1015-1030Fang, Y., Lu, Z., Lin, L., Feng, H., and Chang, J. (2016). "Accelerated air-coupled ultrasound imaging of wood using compressed sensing," BioRes. 11(1), 1015-1030.AbstractArticlePDF

    Air-coupled ultrasound has shown excellent sensitivity and specificity for the nondestructive imaging of wood-based material. However, it is time-consuming, due to the high scanning density limited by the Nyquist law. This study investigated the feasibility of applying compressed sensing techniques to air-coupled ultrasound imaging, aiming to reduce the number of scanning lines and then accelerate the imaging. Firstly, an undersampled scanning strategy specified by a random binary matrix was proposed to address the limitation of the compressed sensing framework. The undersampled scanning can be easily implemented, while only minor modification was required for the existing imaging system. Then, discrete cosine transform was selected experimentally as the representation basis. Finally, orthogonal matching pursuit algorithm was utilized to reconstruct the wood images. Experiments on three real air-coupled ultrasound images indicated the potential of the present method to accelerate air-coupled ultrasound imaging of wood. The same quality of ACU images can be obtained with scanning time cut in half.

  • Researchpp 1031-1043Gao, H., Sun, M. Y., Cheng, H. Y., Gao, W. L., and Ding, X. L. (2016). "Effects of heat treatment under vacuum on properties of poplar," BioRes. 11(1), 1031-1043.AbstractArticlePDF

    The influences of heat treatment under vacuum on the mechanical properties and corrosion resistance of untreated poplar wood were investigated in this study. Wood samples were heated in a vacuum atmosphere in laboratory conditions at 140 to 200 °C for 1 to 3 h. The color of the poplar’s surface after heat treatment was deeper than that of the untreated wood, and the dimensional stability of poplar was improved by increasing the temperature and time. However, the compressive strength parallel to the grain of heat-treated samples was slightly lower than that of the control samples. The modulus of rupture of samples heat-treated at 200 °C for 3 h decreased 41.25% compared with the untreated samples. The corrosion resistance of heat-treated poplar increased with increasing temperature and time. The white-rot fungus resistance of the treated poplar was better than its resistance to brown-rot fungus.

  • Researchpp 1044-1060Hu, Y., Zuo, L., Liu, J., Sun, J., and Wu, S. (2016). "Chemical simulation and quantum chemical calculation of lignin model compounds," BioRes. 11(1), 1044-1060.AbstractArticlePDF

    The conformational preferences of the lignin guaiacyl structural unit were studied by several quantitative chemistry calculation methods using vanillin as a model compound. The potential energy surfaces of the vanillin molecule were scanned by the methods of HF and DFT to find the most stable conformation, as well as three local minimum conformations and six transient conformations. Bonds strength of all kinds of bonds in vanillin molecules at five temperature were calculated by methods of DFT, MP2, and CBS. The calculation results indicated that temperature had little impact on bond strength; the large bond strength was Ar-OH, Ar-H, followed by Ar-CHO, Ar-OCH3, and the C-H in the aldehyde group, and O-CH3 bond strength in methoxyl was lowest (only 61 Kcal/mol), which may be cracked in pyrolysis. The calculation about the model dimer O-α-β-O-4 also showed that the stable order was O-4 > 1-α> α-β> β-O, which agreed well with the fact that there are a lot of phenolic compounds in pyrolysis products of biomass or lignin.

  • Researchpp 1061-1070Bodnár, F., Beňo, P., Kotšmíd, S., and Luptáková, J. (2016). "Influence of boundary conditions on the solution to a mathematical model for a given wooden plate," BioRes. 11(1), 1061-1070.AbstractArticlePDF

    The article examines deformation of wood veneer and internal forces resulting from bending. Wood is modelled as an orthotropic material. A thin circular wooden plate hemispherically supported at its free edge is bent by axial hubbing of the punch with a hemispherical end. The analysis of the models is carried out by the ANSYS software. Geometric boundary conditions are calculated and set by a macro formed by the APDL (ANSYS Parametric Design Language) scenario language. For the reason of comparison the models were solved for a given plate with simplified boundary conditions.

  • Researchpp 1071-1079Ordaz-Díaz, L. A., Valle-Cervantes, S., Rojas-Contreras, J. A., Rodríguez-Flores, F. J., and Bailón-Salas, A. M. (2016). "Optimization of a microbial formulation acclimated for pilot-scale biodegradation of paper mill effluent," BioRes. 11(1), 1071-1079.AbstractArticlePDF

    A pilot-scale aerated lagoon was used for the aerobic treatment of pulp and paper mill effluent from September 1 to December 1, 2014. The aerated lagoon was installed at the chemistry laboratory in the Chemical Engineering Department at the Durango Institute of Technology and was fed with real pulp and paper mill effluent. The experimental work was run under various operating conditions. The operating parameters (total and volatile suspended solids (VSS) and dissolved oxygen concentration (DO)) and environmental variables (temperature, pH, COD, and BOD5 of influent water) were monitored daily. In all the experiments conducted, the aerated lagoon generated an effluent of optimal quality complying with the requirements of SEMARNAT (2003) and CONAGUA (2003). A model that explains the behavior of the system under realistic operating conditions was obtained. The model indicated an optimal DO of approximately 4 mg/L for concentrations up to 1000 mg/L, showing variations in concentrations above this value. This data indicate that the flexibility of the bacterial formulation and its ability to adapt to environmental changes play an important role in the stability of an aerated lagoon.

  • Researchpp 1080-1091Abdul Karim, A. F., Ismail, H., and Ariff, Z. M. (2016). "Properties and characterization of kenaf-filled natural rubber latex foam," BioRes. 11(1), 1080-1091.AbstractArticlePDF

    Kenaf powder was incorporated with natural rubber latex (NRL) compound and foamed to make natural rubber latex foam (NRLF) by using a well known technique called the Dunlop method. Different loadings of kenaf powder were added to NRL compound and was foamed to make NRLF. The mechanical properties, density, compression, thermal, and micro-structural characterization of control NRLF and kenaf incorporated NRLF were studied. Increasing content of kenaf reduced the tensile strength, elongation at break, and compressive strength of a NRLF. Modulus at 100% elongation and density of the NRLF increased with an increase in filler loading. Higher kenaf loading indicated higher elasticity of kenaf-filled NRLF, but the recovery percentage of kenaf-filled NRLF decreased with increasing kenaf loading. From thermogravimetric analysis (TGA) result, an increase in the amount of kenaf loading from 1 to 7 phr increased the thermal stability of kenaf-filled NRLF. Morphological and micro-structural characterization performed by using scanning electron microscopy (SEM) showed that kenaf powder filled up the micro-sized pores in the open cell structure of kenaf-filled NRLF.

  • Researchpp 1092-1107El-Naggar, A. H., Alzhrani, A. K. R., Ahmad, M., Usman, A. R. A., Mohan, D., Ok, Y. S., and Al-Wabel, M. I. (2016). "Preparation of activated and non-activated carbon from Conocarpus pruning waste as low-cost adsorbent for removal of heavy metal ions from aqueous solution," BioRes. 11(1), 1092-1107.AbstractArticlePDF

    Conocarpus pruning waste, an agricultural byproduct, was converted into low-cost activated and non-activated carbons and used for the remediation of Cd2+, Cu2+, and Pb2+ from aqueous solutions. The carbonization was carried out at 400 °C, while the activation was carried out in the presence of KOH and ZnCl2. Batch single-solute and multi-solute equilibrium and kinetic experiments were carried out to determine the adsorption capacities of the prepared activated and non-activated carbons, and these were further compared with commercially available activated carbon. The results showed that KOH-activated carbon (CK) outperformed the other activated and non-activated carbons in terms of adsorption efficiency. CK removed >50% of the applied Cd2+ and Cu2+ and 100% of Pb2+ at the initial concentration of 40 mg L-1. Interestingly, the performance of Conocarpus-derived non-activated carbon was better than that of the commercial activated carbon, as observed from the Langmuir maximum adsorption capacities of 65.61, 66.12, and 223.05 µmol g-1 for Cd2+, Cu2+, and Pb2+, respectively. The Pb2+ was the metal most easily removed from aqueous solution because of its large ionic radius. The kinetic dynamics were well described by the pseudo-second order and Elovich models.

  • Researchpp 1108-1124Su, W., Chen, C., Xu, H., Yang, W., and Dai, H. (2016). "Filtering whitewater with an ultrafiltration membrane: Effects of the interaction between dissolved organics and metal ions on membrane fouling," BioRes. 11(1), 1108-1124.AbstractArticlePDF

    The mechanisms regarding the influence of dissolved organics in papermaking whitewater together with metal ions on the fouling of an ultrafiltration (UF) membrane were studied in this paper. A series of experiments were carried out to characterize the organic matters’ size and membrane flux. The associated fouling mechanism was investigated using the modified Hermia empirical model, resistance distribution, and specific resistance of the cake layer. The results indicated that the addition of metal ions aggravated membrane fouling. Increasing concentrations of metal ions resulted in the higher specific resistance of the cake layer and greater membrane fouling due to their chelation with dissolved organics. Increased pH values influenced the interaction between the metal ions and dissolved organics, resulting in a relatively slow membrane flux decline. Increasing concentrations of Na+ resulted in greater membrane fouling. Cake layer formation played a major role in treating the water samples with high-concentration metal ions, whereas intermediate blocking formation may be the dominant fouling mechanism when treating the solution without metal ions.

  • Researchpp 1125-1140Solala, I., Koistinen, A., Siljander, S., Vuorinen, J., and Vuorinen, T. (2016). "Composites of high-temperature thermomechanical pulps and polylactic acid," BioRes. 11(1), 1125-1140.AbstractArticlePDF

    High-temperature thermomechanical pulps (HT-TMP, defibrated at 150 to 170 °C) were compared to a reference TMP (defibrated at 130 °C) as a reinforcement for polylactic acid (PLA). Composites were prepared by melt compounding, followed by injection molding, gradually increasing the used fiber content from 0 to 20 wt.%. The injection-molded specimens were characterized by tensile and impact strength tests, scanning electron microscopy, water absorption tests, and differential scanning calorimetry. The TMP fiber damage was also characterized before and after melt compounding by optical analysis. At 20% fiber content, the Young’s modulus increased significantly, while the tensile strength remained unchanged and the impact strength decreased slightly. All fibers suffered damage during melt compounding, but the tensile strength remained about the same as in pure PLA. All types of TMP were able to increase the PLA rate of crystallization. The HT-TMP fibers were dispersed more evenly in PLA than the 130 °C TMP. The 170 °C TMP produced composites of lower water absorption than the other two TMP types, probably because of its lower hemicellulose content and its higher surface coverage by lignin.

  • Researchpp 1141-1161Liu, X., Smith, G. D., Jiang, Z., Bock, M. C. D., Boeck, F., Frith, O., Gatóo, A., Liu, K., Mulligan, H., Semple, K. E., Sharma, B., and Ramage, M. (2016). "Nomenclature for engineered bamboo," BioRes. 11(1), 1141-1161.AbstractArticlePDF

    In recent years, there has been a rapid rise in the development of engineered bamboo materials, which have the potential to play an important role as alternatives to conventional building materials. Despite the growing diversity of bamboo products available on the market, the international standardization of both bamboo products and their constituent elements is limited, and a lack of universal nomenclature is recognized as one of the main constraints on developing standards. Similar or identical terminology is used interchangeably to describe different bamboo elements, processes, or products across sectors and continents. In some cases, translated colloquial names are misleading and scientifically inaccurate, which forms a barrier to global collaboration and research, creates ambiguity, and potentially limits trade. The present work aims to address this gap by proposing a set of appropriate terms in English that accurately describe and differentiate between currently produced engineered bamboo products and their constituent elements, accompanied by parallel terms in Chinese and Spanish. From these, new categories of engineered bamboo building materials are proposed for the Harmonized System of product codes. This paper highlights current ambiguities and provides terminology together with clear definitions of the main primary elements, processing steps, and products.

  • Researchpp 1162-1175Zahari, N. I., Md Shah, U. K., Mohamed Asa’ari, A. Z., and Mohamad, R. (2016). "Selection of potential fungi for production of cellulase-poor xylanase from rice straw," BioRes. 11(1), 1162-1175.AbstractArticlePDF

    Recently, xylanase has attracted attention in the pulp and paper industry because of its bleach-boosting properties, which reduces chemical consumption during the bleaching process. Four fungi species, namely Penicillium oxalicum T3.3, Aspergillus niger ATCC 6275, Colletotrichum gloeosporioides,and Pycnoporus sanguineus, were studied to select which fungi can best produce cellulase-poor xylanase using rice straw as a substrate. The fungi were screened for xylanase production based on the clear zone formation on a malt extract agar (MEA) plate containing xylan. P. oxalicum T3.3 and A. niger ATCC 6275 showed greater clear zone formation on the agar plate than the other two studied fungi. These fungi were grown in a liquid medium containing rice straw as the substrate. P. oxalicum T3.3 showed the highest xylanase activity (65.89 U/mL) with lowest carboxymethyl cellulase (CMCase) (1.88 U/mL) and filter paperase (FPase) activity (0.16 U/mL) after four days of fermentation at 30 °C. P. oxalicum T3.3 produced higher xylanase activity when rice straw was used as a substrate compared to commercial xylan. Thus, cellulase-poor xylanase produced from P. oxalicum T3.3 has high potential for biobleaching application in the pulp and paper industry in terms of technical and biological performance and economical aspects.

  • Researchpp 1176-1188Salman, S. D., Leman, Z., Sultan, M. T. H., Ishak, M. R., and Cardona, F. (2016). "The effects of orientation on the mechanical and morphological properties of woven kenaf-reinforced poly vinyl butyral film," BioRes. 11(1), 1176-1188.AbstractArticlePDF

    Kenaf is one of the important plants cultivated for natural fibres globally and is regarded as an industrial crop in Malaysia for various applications. This study was conducted to determine the effects of orientation on the tensile and flexural strengths, Charpy impact test, and morphological properties of kenaf fibre-reinforced poly vinyl butyral (PVB) composites. Laminates of 40% fibre weight fraction were manufactured using the hot press manufacturing technique at 0°/90° and 45°/−45° orientations, and eight specimens were prepared for each test. The mechanical properties of the composites were variably affected by the fibre orientation angle. The results showed that the composites at 0o/90o had the highest tensile strength, flexural strength, and flexural modulus, while the elongation at break was almost the same. Additionally, tests were carried out on the composites to determine their impact energy and impact strength. The results revealed that impact properties were affected in markedly different ways by different orientations. The composite at 45°/−45° offered better impact properties than the composites at 0°/90°. In addition, scanning electron microscopy for impact specimens was employed to demonstrate the different failures in the fracture surfaces.

  • Researchpp 1189-1201Ratnasingam, J., Ramasamy, G., Ioras, F., Thanesegaran, G., and Mutthiah, N. (2016). "Assessment of dust emission and working conditions in the bamboo and wooden furniture industries in Malaysia," BioRes. 11(1), 1189-1201.AbstractArticlePDF

    A study was carried out to assess the dust emission and working conditions in the bamboo and rubberwood furniture manufacturing industries in Malaysia. The emission of wood dust arising from these industries was measured in each main work station in the mills. Meanwhile, a questionnaire-based survey was conducted among 5900 workers in 45 companies to obtain information on the occupational accidents that occurred in the mills. The data were collected, compiled, and analyzed using the SPSS package. The highest dust emission from the sanding operation resulted in respiratory ailments among workers. The occurrence of injuries particularly to the hand, wrist, fingers and forearm was due to the prevailing working conditions, safety climate and workers characteristics. The dust exposure levels and working conditions were much more severe in the bamboo furniture manufacturing industry. As a result, a review of existing of dust exposure levels in the woodworking industry is warranted.

  • Researchpp 1202-1213Wang, Y., Zhan, H., Ding, Y., Wang, S., and Lin, S. (2016). "Variability of anatomical and chemical properties with age and height in Dendrocalamus brandisii," BioRes. 11(1), 1202-1213.AbstractArticlePDF

    Dendrocalamus brandisii is an edible bamboo species found in Southwest China and South Asia. However, there is limited information about the anatomical and chemical information of its culms for its utilization and processing. In this paper, the anatomical and chemical properties of different age culms were determined. There are three vascular bundle types found in its culms. The radial length-to-tangential diameter ratio of vascular bundles varied with culm zone but did not vary with age. The outer diameter of metaxylem vessels showed a similar trend. The fiber length (L), wall thickness (W), and Runkel ratio increased with age, while the fiber length-to-outer diameter ratio (L/D) and lumen diameter (Ld) decreased with age. The chemical properties of D. brandisii also differed with age class and height. The holocellulose and ash content decreased from age 1 to 2 years and then increased at year 3. The acid-insoluble lignin, alcohol-toluene extractives, and silica contents increased with age class, whereas the acid-soluble lignin exhibited the opposite trend. The fiber length and L/D values of D. brandisii suggest it would be suitable material for pulp fibers, but its lignin content was relatively high compared with other bamboo species.

  • Researchpp 1214-1223Lee, J. H., Jeong, S. G., and Kim, S. (2016). "Performance evaluation of infrared bake-out for reducing VOCs and formaldehyde emission in MDF panels," BioRes. 11(1), 1214-1223.AbstractArticlePDF

    Building materials can release a wide range of pollutants, particularly the volatile organic compounds (VOCs) and formaldehyde, which can cause indoor air related health problems. Bake-out technology is a cost-efficient method to reduce emissions of toxic substance from building materials in residential housing units. The temperature rise and the bake-out performance of MDF panels were evaluated in this work with three types of infrared radiation apparatus. Each MDF panel was radiated from three types of infrared radiation apparatus over 24 hours. The temperature was confirmed using data logging equipment according to elapsed time of infrared radiation. The formaldehyde emission was analyzed by desiccator method. In addition, thermal extractor (TE) analysis was used to determine the effect of NIR radiation on elapsed time. From the results it was determined that the NIR radiation method can be regarded as an effective way to transfer heat from material’s surface to the other side. Furthermore, the bake-out performance confirmed that the NIR radiation had a significant effect on reducing the formaldehyde concentration within a short period of radiation time.

  • Researchpp 1224-1239Smardzewski, J., Rzepa, B., and Kılıç, H. (2016). "Mechanical properties of externally invisible furniture joints made of wood-based composites," BioRes. 11(1), 1224-1239.AbstractArticlePDF

    The aim of this investigation was to design and determine the mechanical properties of innovative, externally invisible, 3D-printed cabinet furniture joints that can be assembled without the use of tools. The cognitive objective of the study was to ascertain the stiffness and strength of designed joints that differed in the number and length of fasteners, as well as in the kind of connected panel materials. During the tests, a digital image analysis method was used for verifying analytical calculations. The finite element method was used for determining the mechanical properties of joints. Results showed that the joint designed with a dual-conical fastener was characterized by high stiffness and strength. The stiffness and strength of the joint depended on the number and length of fasteners. The low level of stress in the panel elements guaranteed durable, safe utilization of cabinet furniture made of medium density fiberboard and particleboard. In conclusion, ease of assembly and disassembly of joints without tools, external invisibility, good aesthetics, high resistance, and stiffness ensure a high potential for 3D-printed cabinet furniture joints in industry and trade.

  • Researchpp 1240-1254Yang, Q., Zhou, S., and Runge, T. (2016). "Dairy manure as a potential feedstock for cost-effective cellulosic bioethanol," BioRes. 11(1), 1240-1254.AbstractArticlePDF

    This study investigated sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL) pretreatment and subsequent enzymatic digestibility of undigested dairy manure to preliminarily assess its potential use as an inexpensive feedstock for cellulosic bioethanol production. The sulfite pretreatment was carried out in a factorial analysis using 163 to 197 °C for 3 to 37 min with 0.8% to 4.2% sulfuric acid combined with 2.6% to 9.4% sodium sulfite. These treatments were compared with other standard pretreatments of dilute acid, and hot and cold alkali pretreatments. This comparative study showed that the sulfite pretreatment, through its combined effects of hemicellulose and lignin removal and lignin sulfonation, is more effective than the diluted acid and alkali pretreatments to improve the enzymatic digestibility of dairy manure.

  • Researchpp 1255-1269Yaacob, N. D., Ismail, H., and Sung Ting, S. (2016). "Soil burial of polylactic acid/paddy straw powder biocomposite," BioRes. 11(1), 1255-1269.AbstractArticlePDF

    The objective of this work was to study the biodegradability of polylactic acid (PLA)/paddy straw powder (PSP) biocomposites. Environmental degradation was evaluated by composting the biocomposite samples into the soil. Different techniques, including mechanical tests and scanning electron microscopy (SEM), were used to obtain a view of the degradation that occurred during the soil burial of the biocomposites. Results of the mechanical tests showed that an increasing content of PSP in the biocomposites decreased the tensile strength and elongation at break (EB), while it increased the modulus of elasticity after six months of exposure. Scanning electron microscopy on the surface after soil burial showed that the filler was poorly wetted by the matrix. This explains the reduction in tensile strength and the elongation at break after soil burial. Differential scanning calorimetry results indicated that the crystallinity of the biocomposites increased with longer composting periods.

  • Researchpp 1270-1279Nur Firdaus, M. Y., Osman, H., Metselaar, H. S. C., and Rozyanty, A. R. (2016). "A simple method for the production of pure crystalline silica from lemon grass," BioRes. 11(1), 1270-1279.AbstractArticlePDF

    Lemon grass is an inexpensive raw material that can be used to produce natural silica. A method using hydrochloric acid (HCl) leaching followed by thermal combustion at 600 °C was developed to produce purified silica from lemon grass. Acid leaching temperatures of 33, 50, 80, and 110 °C were used. The silica content of the lemon grass ash was characterized using X-ray fluorescence (XRF), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) analysis. The shape and texture of the lemon grass ash were studied using SEM. The highest silica content (98.59%) was produced by lemon grass that had been treated at the highest leaching temperature (110 °C). Other elements that were found in the lemon grass ash were magnesium, calcium, potassium, and chlorine. XRD analysis showed that the crystallinity of the silica in treated lemon grass ash increased with increasing leaching temperature. The FTIR analysis confirmed the presence of siloxane and silanol bonds in lemon grass that was calcined at different leaching temperatures.

  • Researchpp 1280-1295Guo, H., Zhang, S., Du, L., Liang, J., Zhi, S., Yu, J., Lu, X., and Zhang, K. (2016). "Effects of thermal-alkaline pretreatment on solubilisation and high-solid anaerobic digestion of dewatered activated sludge," BioRes. 11(1), 1280-1295.AbstractArticlePDF

    The effects of thermal-alkaline pretreatment on dewatered activated sludge (DAS) solubilisation and subsequent high-solid anaerobic digestion were studied by response surface methodology (RSM) from 105 to 135 °C and between 5 and 35 mg alkaline/g total solid (TS) DAS. Soluble chemical oxygen demand (SCOD), soluble carbohydrates, and protein concentrations were significantly enhanced in thermal-alkaline pretreated DAS samples. Daily methane yield increased at the middle of digestion, and cumulative methane yield (CMY) significantly increased after thermal-alkaline pretreatment. A first-order linear model of temperature and alkaline was significant for SCOD by RSM, and the determination coefficient (R2) was 94.62%. The quadratic model of temperature and alkaline was also significant for methane yield. R2 of 99.80% confirmed that the model used in this study fit the experimental variables very well. Using the model, the optimum pretreatment condition of methane yield was obtained at 134.95 °C and 23.77 mg alkali. Therefore, RSM was an effective tool in predicting the DAS pretreatment condition for optimum methane yield.

  • Researchpp 1296-1306He, W., Wang, M., Jin, X., and Song, X. (2016). "Cationization of corncob holocellulose as a paper strengthening agent," BioRes. 11(1), 1296-1306.AbstractArticlePDF

    In this paper, milled corncob powder was treated with sodium chlorite to remove lignin, and the resulting holocellulose was optionally modified with cationic agent. The derivative product was investigated using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The influences of the dosage of the cationic agent, reaction temperature, particle size, dosage of paper strengthening agent, and pH value of the pulp on the paper physical properties were studied. The results indicated that cationic corncob holocellulose can improve the tensile index, burst index, and folding endurance of paper. When the dosage of cationic agent was 25% and the reaction temperature was set to 70 °C, the resulting tensile index, burst index, and folding endurance increased by 7.15%, 13.74%, and 55.95%, respectively, when compared with the control paper. The particle size of the raw material and the dosage of strengthening agent also greatly influenced the paper’s properties. The SEM analysis showed that the combination of fibers improved the strength properties of the paper after adding the strengthening agent. These results provide a method for value-added use of corncob waste.

  • Researchpp 1307-1318Bi, R., Oinonen, P., Wang, Y., and Henriksson, G. (2016). "A method for studying effects on lignin-polysaccharide networks during biological degradation and technical processes of wood," BioRes. 11(1),1307-1318.AbstractArticlePDF

    Woody tissues consist primarily of a mixture of cellulose, hemicelluloses, and lignin. Covalent bonds between lignin and polysaccharides likely play a central role in determining the mechanical and physical properties of wood. Intact and defined lignin-polysaccharide networks have not been isolated in large quantities because of the recalcitrance of lignin, which demands harsh chemical treatments that alter its structure. This report presents a method for preparing large quantities of lignin-polysaccharide networks similar to those naturally present in wood based on the enzymatic oxidation of hemicellulose from Norway spruce. Fungal enzymes produced from various carbon sources were used to depolymerize these networks. The method was used for simulating “enzyme mining” – a concept in biorefineries, giving a possible explanation for its mechanisms.

  • Researchpp 1319-1333Zhao, Z., Umemura, K., and Kanayama, K. (2016). "Effects of the addition of citric acid on tannin-sucrose adhesive and physical properties of the particleboard," BioRes. 11(1), 1319-1333.AbstractArticlePDF

    The effects of citric acid on the curing properties of tannin-sucrose adhesives and on the physical properties of particleboard utilizing the adhesives were investigated. The citric acid content of tannin-sucrose adhesive was adjusted to 0.4, 1.8, 4.6, 13.8, 20.0, and 33.3%, which corresponded to pH values of the adhesive 40 wt% solution at 3.8, 3.0, 2.5, 2.0, 1.8, and 1.5, respectively. Thermal analysis showed that with increasing of citric acid content, the temperature of significant weight loss and the endothermic reaction of the tannin-sucrose-citric acid adhesive was reduced. When the adhesives were heated at 200 °C, boiled for 4 h, and adjusted to 20.0 and 33.3% citric acid content, the insoluble matter was increased significantly, and an absorption band derived from ester linkages and another peak, possibly from dimethylene ether bridges, were observed by FT-IR. The particleboards bonded with 20.0 and 33.3% citric acid adhesives at 200 °C satisfied the physical requirements of the type 18 Japanese Industrial Standards A 5908 (2003). Consequently, the addition of citric acid promoted the reaction between tannin and sucrose at a lower temperature, and the optimal hot pressing temperature decreased from 220 to 200 °C. The mechanical properties and water resistance of the particleboards were also enhanced.

  • Researchpp 1334-1348Behazin, E., Ogunsona, E., Rodriguez-Uribe, A., Mohanty, A. K., Misra, M., and Anyia, A. O. (2016). "Mechanical, chemical, and physical properties of wood and perennial grass biochars for possible composite application," BioRes. 11(1), 1334-1348.AbstractArticlePDF

    Miscanthus, switchgrass, and softwood chip biochars, produced by slow pyrolysis, were characterized to evaluate their properties in light of potential alternative and novel applications. This work investigated specific physical and chemical properties of biochars that have not been previously reported. Atomic force microscopy (AFM), moisture absorption, and electrical and thermal analysis were conducted to demonstrate the mechanical, physical, and chemical properties of biochars. In addition, elemental analysis, specific surface area, Fourier transform infrared in the attenuated total reflectance (FTIR-ATR), and X-ray diffraction were performed. The state-of-art quantitative nano-mechanical measurement yielded a modulus of elasticity of approximately 10 GPa for the wood chip biochar, while the grass-based samples exhibited a comparatively lower modulus of approximately 5 GPa. In addition, the pore blocking phenomenon by water molecules was identified as a cause for atypical behavior of the biochars’ moisture absorptions, resulting in wood chip biochar having the lowest equilibrium moisture content of 6.2 wt.%. Results from electrical and thermal conductivity measurements demonstrated relatively lower values in comparison to carbonized biomass.

  • Researchpp 1349-1358Ang, T. N., Chan, C. H., Ngoh, G. C., Lee, K. M., Yoon, L. W., and Chua, A. S. M. (2016). "Assessment of cellulosic biomass saccharification by molten Brönsted acidic 1-ethyl-3-methylimidazolium hydrogen sulphate ([EMIM]HSO4]) via kinetic studies," BioRes. 11(1), 1349-1358.AbstractArticlePDF

    Ionic liquids have been employed to deconstruct and fractionate lignocellulosic biomasses because of their capacity to dissolve cellulose. However, there is limited literature reporting the use of ionic liquids in biomass saccharification, which mostly involves the addition of acid or water that conceals the true action of ionic liquid in saccharification. This article assesses the performance of molten Brӧnsted acidic 1-ethyl-3-methylimidazolium hydrogen sulphate ([EMIM][HSO4]) in saccharifying three agricultural biomasses, namely sago hampas, sugarcane bagasse, and rice husk, via saccharification kinetics. At 100 °C, [EMIM][HSO4] saccharification of the biomasses achieved equilibrium reducing sugar yields at various durations (sago hampas, 3 h; sugarcane bagasse, 1 h; rice husk, 5 h). The kinetic rate constant was obtained from model fitting, indicated that [EMIM][HSO4] showed a preference for saccharifying less recalcitrant sugarcane bagasse (37.9%) than sago hampas (7.0%) and rice husk (1.1%). Compared to H2SO4 saccharification, reducing sugar yields of [EMIM][HSO4] were consistently lower. The difference in yields might be attributed to the hydrous/anhydrous state of reaction and limited availability of component ions of the ionic liquid for dissolution and saccharification. This study demonstrates the feasible technical aspects of applying [EMIM][HSO4] to saccharify agricultural biomasses, which may lead to economic feasibility, recyclability, and cost effectiveness of ionic liquids in saccharification.

  • Researchpp 1359-1368Li, H., Xian, Y., Deng, J., Cheng, H., Chen, F., and Wang, G. (2016). "Evaluation of water absorption and its influence on the physical-mechanical properties of bamboo-bundle laminated veneer lumber," BioRes. 11(1), 1359-1368.AbstractArticlePDF

    To investigate the possibility of using bamboo-bundle laminated veneer lumber (BLVL) as a cooling tower packing material, the water absorption rates, thickness swelling rates, and flexural properties of three different composite materials were studied. The BLVL was combined with either 12% or 24% phenol formaldehyde resin (PF), and the moso bamboo strips were exposed to water baths at three different temperatures (45, 65, and 85 °C) for 30 d. After the aging treatments, the 24%-BLVL samples showed lower water absorption rates and better bending properties than the other two composites. The temperature was found to have a significant effect on the modulus of rupture (MOR), modulus of elasticity (MOE), and the thickness swelling rate. As the temperature increased, the swelling rate and the rate of weight gain increased and the MOE and MOR decreased. According to the activation energies for swelling calculated from the Arrhenius-type plots, compared with the 24%-BLVL (22.95 kJ·mol-1) and the moso bamboo strips (12.69 kJ·mol-1), the effect of temperature on the swelling rate was greatest for the 12%-BLVL (24.15 kJ·mol-1). Results showed that the BLVL material is a promising candidate for a novel cooling tower packing material.

  • Researchpp 1369-1381Torniainen, P., Elustondo, D., and Dagbro, O. (2016). "Industrial validation of the relationship between color parameters in thermally modified spruce and pine," BioRes. 11(1), 1369-1381.AbstractArticlePDF

    Thermal modification causes the darkening of wood throughout its cross-section because of chemical changes in the wood. After treatment, naturally light wood species look darker or even tropical, depending predominantly on the treatment temperature and processing time. This study investigates the suitability of using color measurement to determine treatment intensity at the industrial scale. The color was determined using the L*, a*, and b* color space, also referred to as CIELab, and the relationship between lightness (L*) and the color parameters (a*) and (b*) was investigated for thermal modification treatments at 190 and 212 °C. The wood species studied were pine (Pinus sylvestris L.) and spruce (Picea abies L.). The results showed that yellowness (+b*) and redness (+a*) had a significant prediction ability for class treatments at 190 and 212 °C, respectively. After treatment, there were no noticeable differences in color between the species, but sapwood was darker than heartwood in both untreated and thermally modified wood. The thickness of the boards had a proportionally darkening effect on the color values.

  • Researchpp 1382-1392Gaff, M., Ruman, D., Gašparík, M., Štícha, V., and Boška, P. (2016). "Tensile-shear strength of glued line of laminated veneer lumber," BioRes. 11(1), 1382-1392.AbstractArticlePDF

    This article presents an investigation of the influence of selected factors (wood species, composition, and number of loading cycles) on the shear strength of laminated veneer lumber previously affected by cyclic loading. The monitored properties were determined on samples of European beech (Fagus sylvatica L.) and Eurasian aspen (Populus tremula L.). The laminated veneer lumber consisted of a combination of densified and non-densified veneers. Wood densification of up to 30% was carried out by means of rolling. The results show that each monitored factor significantly influenced the shear strength. The results also indicate a significant decrease in glued joint shear strength with increasing number of densified veneers in the laminated veneer lumber.

  • Researchpp 1393-1406Kada, D., Migneault, S., Tabak, G., and Koubaa, A. (2016). "Physical and mechanical properties of polypropylene-wood-carbon fiber hybrid composites," BioRes. 11(1), 1393-1406.AbstractArticlePDF

    Effects of the addition of short carbon fibers (CFs) on the mechanical, physical, and morphological properties of polypropylene (PP) and wood-polypropylene composites (WPCs) were investigated. Hybrid composites (mix of wood and CFs) were manufactured in a two-stage process, pellet extrusion and samples mold injection with varying amounts of poplar wood fiber (0%, 20%, 30%, and 40%) and CFs (0%, 3%, 6%, and 9%), with and without maleic anhydride grafted PP (MAPP) as a coupling agent. The composites were prepared with extrusion blending followed by injection molding. The samples where then tested for mechanical and physical properties, and fractured surfaces where observed with scanning electron microscopy. The results indicated that the addition of CFs to WPCs improved the tensile and flexural strength and the modulus of elasticity but had only a small influence on elongation at break and impact strength. The density of hybrid composites slightly increased with CFs proportion but their water absorption was not affected. Scanning electron micrographs of the tensile fractured specimens showed improved adhesion of CFs and poplar with the PP matrix in the presence of a coupling agent.

  • Researchpp 1407-1416Zhang, X., Cai, Z., Chen, L., Zhang, D., and Zhang, Z. (2016). "Effects of moisture content and temperature on the quality of water hyacinth pellets," BioRes. 11(1), 1407-1416.AbstractArticlePDF

    Moisture content and temperature are two important process parameters that greatly influence the quality of biomass pellet fuels. The moisture content of raw material was varied at five levels (8%, 10%, 12%, 14%, 16%) to test its effect on water hyacinth pellet density and diametric compression strength. The experimental conditions included a compressing force of 6 kN, hammer mill screen size of 2 mm, and temperature of 100 °C. Five temperature conditions (80, 90, 100, 110, and 120 °C) were studied under the same conditions and 12% moisture content. In these conditions, the optimal moisture contents for water hyacinth pellet density and diametric compression strength were 12.2% and 11.5%, respectively, and the optimal temperatures were 100.4 °C and 104.3 °C, respectively.

  • Researchpp 1417-1431Ma, P., Lan, J., Feng, Y., Liu, R., Qu, J., and He, H. (2016). "Effects of continuous steam explosion on the microstructure and properties of Eucalyptus fibers," BioRes. 11(1), 1417-1431.AbstractArticlePDF

    Laboratory-designed continuous steam explosion (CSE) equipment was used to prepare continuous steam-exploded eucalyptus fibers (CSEEFs). The pretreatment intensity was varied by changing treatment time, and effects of CSE on the composition, microstructure, surface composition, thermal properties, and crystallinity of CSEEFs were investigated. Composition analysis showed that CSE had a significant impact on lignin and hemicellulose, but little on cellulose. Scanning electron microscopy indicated that the middle lamella, primary wall, and outer secondary wall were progressively stripped as the CSE time increased. X-ray photoelectron spectroscopy demonstrated that concentrations of extractives and lignin were higher on the surface of eucalyptus wood than CSEEFs’, and the exposed carbohydrate fraction increased with increasing CSE time. Differential scanning calorimetry showed that eucalyptus wood has one glass transition (193.5 °C), whereas two glass transitions at 56.7 and 138.5 °C were observed for CSEEF-5. X-ray diffraction results suggested that crystallinity of samples decreased with increasing CSE time. Thermogravimetric analysis showed the pyrolysis peak temperature of samples first increased and then decreased slightly as CSE time increased. These data will be useful for the optimization and application of CSE technology.

  • Researchpp 1432-1447Mook, W. T., Aroua, M. K., and Szlachta, M. (2016). "Palm shell-based activated carbon for removing reactive black 5 dye: Equilibrium and kinetics studies," BioRes. 11(1), 1432-1447.AbstractArticlePDF

    Activated carbon derived from biomass waste, namely palm shell, was evaluated as a potential adsorbent for the removal of Reactive Black 5 dye (RB5) from an aqueous solution. This work focused on the equilibrium isotherms and the kinetics of the adsorption process. Batch adsorption tests were conducted to determine the effects of various parameters, such as contact time, RB5 concentration, adsorbent dose, temperature, and initial solution pH, on the treatment performance. The adsorption capacity of the adsorbent used in the study was higher in an acidic medium. The Langmuir model provided the best fit for the obtained equilibrium isotherm data, while the adsorption kinetics was best represented by the pseudo-first-order model. RB5 adsorption was endothermic in nature, with an activation energy of 12.6 kJ/mol. The maximum adsorption capacity of the adsorbent was 25.1 mg/g at pH 2. Palm shell-based activated carbon is shown to have great potential in the adsorption of RB5 from aqueous solution.

  • Researchpp 1448-1465Sharba, M. J., Leman, Z., Sultan, M. T. H., Ishak, M. R., and Azmah Hanim, M. A. (2016). "Effects of kenaf fiber orientation on mechanical properties and fatigue life of glass/kenaf hybrid composites," BioRes. 11(1), 1448-1465.AbstractArticlePDF

    The objectives of this work were to investigate the effect of kenaf fiber alignment on the mechanical and fatigue properties of kenaf/glass hybrid sandwich composites. Three types of kenaf fibers were used, namely, non-woven random mat, unidirectional twisted yarn, and plain-woven kenaf. A symmetric sandwich configuration was constructed with glass as the shell and kenaf as the core with a constant kenaf/glass weight ratio of 30/70% and a volume fraction of 35%. Tensile, compression, flexural, and fully reversed fatigue tests were conducted, and a morphological study of the tensile failure surface of each hybrid composite was carried out. The non-woven mat kenaf hybrid had poor properties for all tests, while the unidirectional kenaf hybrid composite possessed higher tensile strength and similar compressive properties compared with the woven kenaf. Hybridization with kenaf fibers improved the fatigue degradation coefficient of the final composites to 6.2% and 6.4% for woven and unidirectional kenaf, respectively, compared with 7.9% for non-woven. Because woven kenaf hybrid composite is lightweight, environment friendly, and has a considerable balance in static and fatigue strengths with low fatigue sensitivity in bidirectional planes compared to glass, it is strongly recommended for structural applications.

  • Researchpp 1466-1476Sharba, M. J., Salman, S. D., Leman, Z., Sultan, M. T. H., Ishak, M. R., and Azmah Hanim, M. A. (2016). "Effects of processing method, moisture content, and resin system on physical and mechanical properties of woven kenaf plant fiber composites," BioRes. 11(1), 1466-1476.AbstractArticlePDF

    Effects of the processing method, moisture content, and polymer type were evaluated relative to the physical and mechanical properties of composites based on natural plants. When kenaf was heated above the glass transition temperature of lignin, there was a reduction in moisture content by more than 8% of the total weight of the raw material. To investigate polymer behavior, the raw material was reinforced with three types of polymers: epoxy, unsaturated polyester (UP), and vinyl ester fabricated using hand lay-up with cold press (HCP) and vacuum infusion (VI). The results of (HCP) showed a noticeable improvement in tensile and flexural strength and their moduli for all types of polymer used compared with (VI), in ascending order from UP and vinyl ester to epoxy. Using the HCP method, the tensile strength improved considerably, by 60% for epoxy, 59% for UP, and 250% for vinyl ester, while flexural strength was enhanced by 16% for epoxy, 126% for UP, and 117% for vinyl ester compared to VI. Impact results showed a slight or no improvement in absorbed energy.

  • Researchpp 1477-1493Thomas, R. E., and Buehlmann, U. (2016). "Potential for yield improvement in combined rip-first and crosscut-first rough mill processing," BioRes. 11(1), 1477-1493.AbstractArticlePDF

    Traditionally, lumber cutting systems in rough mills have either first ripped lumber into wide strips and then crosscut the resulting strips into component lengths (rip-first), or first crosscut the lumber into component lengths, then ripped the segments to the required widths (crosscut-first). Each method has its advantages and disadvantages. Crosscut-first typically works best for the production of wider components, while rip-first favors the production of narrower and longer components. Thus, whichever type of processing method is selected for a given rough mill usually depends on the characteristics of the cutting bills the mill expects to process. There is a third option, a dual-line mill that contains both rip-first and crosscut-first processing streams. To date, such mills have been rare for a variety of reasons, complexity and cost being among them. However, dual-line systems allow the mill to respond to varying cutting bill size demands as well as to board characteristics that favor one method (rip-first or crosscut-first) over the other. Using the Rough Mill Simulator (ROMI 4), this paper examines the yield improvement potential of dual-line processing over single-system processing (i.e., rip-first or crosscut-first processing alone) for a variety of cutting bills and lumber grade mixes.

  • Researchpp 1494-1504Arwinfar, F., Hosseinihashemi, S. K., Latibari, A. J., Lashgari, A., and Ayrilmis, N. (2016). "Mechanical properties and morphology of wood plastic composites produced with thermally treated beech wood," BioRes. 11(1), 1494-1504.AbstractArticlePDF

    The effect of thermal-treatment severity of wood on the mechanical and morphological properties of wood plastic composites (WPCs) was investigated. Wood chips were first heat treated at 120, 150, or 180 ºC for 30 or 120 min under saturated steam in a digester. The composites were composed of thermally treated and untreated wood flour, polypropylene, and a coupling agent, produced by melt compounding and then injection molding. The thermal-treatment of the beech wood improved some mechanical properties of the WPCs, depending on the treatment-time and temperature. The SEM micrographs of the composites showed that the outer surface of the wood fiber was coated by a section of amorphous lignin. The SEM images showed that the WPCs produced from the wood treated at 150 ºC for 30 min had considerably fewer holes and many broken fiber ends embedded in the polymer matrix, indicating better compatibility between the wood flour and the polymer matrix. Based on the results of the mechanical testing of the WPCs, the optimum thermal-treatment for WPC production was 150 °C for 30 min. F

  • Researchpp 1505-1517Hosseinihashemi, S. K., Nazari, L., Lashgari, A., and Salem, M. Z. M. (2016). "Evaluation of inner bark extract of barberry stem and its synergy with propiconazole, EDTA, BHT, and their combinations against white-rot fungus Trametes versicolor," BioRes. 11(1), 1505-1517.AbstractArticlePDF

    The synergistic action of water-methanol (1:1 v/v) inner bark extract of barberry (IBEB) stem and biocide, propiconazole (PCZ), and non-biocidal additives, EDTA, BHT, and their combinations with various concentrations (50, 150, 250, 350, and 450 ppm) against the white-rot fungus, Trametes (Coriolus) versicolor was investigated. Results obtained herein demonstrated that IBEB by itself did not exhibit antifungal property, and enhanced protection was further observed by combining it with PCZ. BHT and PCZ showed inhibition percentages of 54.3% and 43.6%, respectively, against the growth of T. versicolor, which reached 75% with BHT at 50 ppm. A synergistic effect was found by introducing PCZ to IBEB when tested against T. versicolor in vitro, with an inhibition percentage of 62% at 150 ppm. No synergistic action was exhibited from the combination treatment of IBEB+EDTA+BHT, and the activity was enhanced by introducing PCZ to this combination treatment (50% at 350 ppm). Significant synergistic action between each of factors of IBEB+PCZ, EDTA+PCZ, and BHT+PCZ was found with inhibition percentages of 49.7%, 48.6%, and 52.7%, respectively. In conclusion, it is advised that IBEB and PCZ be used clinically at the same time.

  • Researchpp 1518-1540Tee, Y. B., Talib, R. A., Abdan, K., Chin, N. L., Basha, R. K., and Md Yunos, K. F. (2016). "Comparative study of chemical, mechanical, thermal, and barrier properties of poly(lactic acid) plasticized with epoxidized soybean oil and epoxidized palm oil," BioRes. 11(1), 1518-1540.AbstractArticlePDF

    To investigate epoxidized palm oil’s (EPO) potential as plasticizer for poly(lactic acid) (PLA), its plasticizing effect was compared with commercialized epoxidized soybean oil (ESO). The plasticizers were respectively melt-compounded into PLA at 3, 5, 10, and 15 wt.%. As it was aimed for the blends to be characterized towards packaging appropriate for food products, they were hot-pressed into ~0.3-mm sheets, which is the approximate thickness of clamshell packaging. Fourier transform infrared spectroscopy (FTIR) confirmed the plasticizers’ compatibility with PLA. At similar loadings, EPO was superior in reinforcing elongation at break (EAB), thermal, and barrier properties of PLA. The ductility of PLA was notably improved to 50.0% with addition of 3 wt.% of EPO. From thermogravimetric analysis (TGA), PLA/EPO5 improved PLA’s thermal stability, while all PLA/ESO blends reported reduced thermal stability. From differential scanning calorimetry (DSC), the increase in crystallinity and the shifts in enthalpy of fusions in all plasticized blends denoted facilitation of PLA to form thermally stable α-form crystals. The addition of EPO enabled PLA to become highly impermeable to oxygen, which can extend its potential in packaging extensive range of oxygen sensitive food.

  • Researchpp 1541-1553Jin, J., Wu, C., Qin, D., Peng, W., Sun, W., Liu, C., Cao, X., and Niu, X. (2016). "Decay resistance of bamboo oriented strand board pretreated with copper-based preservatives," BioRes. 11(1), 1541-1553.AbstractArticlePDF

    To enhance the decay resistance of bamboo oriented strand board (OSB) products, the strands were dipped in solutions of alkaline copper quat (ACQ) and copper azole (CA) and bonded with phenol formaldehyde resin into two types of OSB panels, i.e., panels with 100% treated strands and those with treated strands only in the face layers. The results indicated that the decay resistance of treated panels was effectively enhanced. The physical and mechanical properties of all treated panels exceeded the requirements specified for category OSB/4 or OSB/3 in the standard LY/T 1580-2010. Statistical data analysis showed that pretreatment with ACQ and CA did not have detrimental effects on the overall physical and mechanical properties of panels at the loading levels investigated in this study. Panels with pretreated strands only in the face layers had strong decay resistance and comparable overall properties as those with 100% treated strands. The results suggest that pretreatment is a promising way to introduce waterborne ACQ and CA to protect bamboo OSB.

  • Researchpp 1554-1570Zhou, C. E., Kan, C. W., Yuen, C. M., Lo, K. C., Ho, C. P., and Lau, K. R. (2016). "Regenerable antimicrobial finishing of cotton with nitrogen plasma treatment," BioRes. 11(1), 1554-1570.AbstractArticlePDF

    The effects of process variables on regenerable antimicrobial finishing of cotton fabric with nitrogen plasma treatment were investigated. Cotton fabric was treated with a mixture of nitrogen and helium plasma, and it was chlorinated with sodium hypochlorite to impart antimicrobial properties. An orthogonal array testing strategy (OATS) was used in the finishing process to determine the optimum treatment conditions. After finishing, the properties of cotton fabric, including concentration of chlorine, tearing strength, and presence of functional groups, were evaluated by ultraviolet spectroscopy (UV), tear testing, and Fourier transform infrared spectroscopy (FTIR). Cotton fabric treated with nitrogen plasma and chlorination effectively blocked microorganism growth. The resistance to Staphylococcus aureus bacteria was regenerable, and nitrogen plasma treatment showed no noticeable influence on the tearing strength of the cotton fabric.

  • Researchpp 1571-1584Chen, M., Zhang, R., Tang, L., Zhou, X., Li, Y., and Yang, X. (2016). "Effect of plasma processing rate on poplar veneer surface and its application in plywood," BioRes. 11(1), 1571-1584.AbstractArticlePDF

    Dielectric barrier discharge (DBD) plasma at atmospheric pressure in air was applied to a poplar veneer surface. Effects of plasma processing rate on surface morphology, chemical property, and surface wettability of the poplar veneer were investigated. The adhesion strength of urea formaldehyde (UF) glued plywood manufactured from the modified veneer was also studied. Atomic force microscopy (AFM), electron spin-resonance spectroscopy (ESR), X-ray photoelectron spectroscopy (XPS), contact angle tests, and shear strength tests were carried out. AFM indicated that the surface roughness increased after plasma treatment and was the maximum at a processing rate of 14 m/min. Both ESR and XPS tests showed more oxygen accumulation on the wood surface, forming various oxygen-containing chemical groups. Contact angle tests showed better wetting at a decreased plasma processing rate. Consequently, the adhesion strength of plywood increased after plasma treatment and showed higher strength at lower processing rates.

  • Researchpp 1585-1595Coumar, M. V., Parihar, R. S., Dwivedi, A. K., Saha, J. K., Lakaria, B. L., Biswas, A. K., Rajendiran, S., Dotaniya, M. L., and Kundu, S. (2016). "Pigeon pea biochar as a soil amendment to repress copper mobility in soil and its uptake by spinach," BioRes. 11(1), 1585-1595.AbstractArticlePDF

    A pot crop experiment was conducted to study the effect of biochar on Cu mobility in a soil-plant system. Pigeon pea biochar was prepared by slow pyrolysis at 300 °C. The experiment had three levels of Cu (0, 250, and 500 mg Cu kg-1 soil) and three levels of biochar (0, 2.5, and 5 g kg-1 soil), using spinach as the test crop. The dry matter yield of edible spinach leaf decreased by 16.7% and 27.9% at 250 and 500 mg Cu kg-1 soil concentration, respectively. The soil organic carbon (SOC) increased by 27.08% and 45.83% at 2.5 and 5 g kg-1 soil application of biochar, respectively. Cu mobility in soil was significantly reduced as a result of biochar application, as evident from the reduction in DTPA extractable Cu in soil, the transfer coefficient value (soil to plant), and the Cu concentration in the leaf and root. The increases in SOC and pH in the biochar amended soil affect copper dynamics because they control adsorption and precipitation on solid phase. Cu has higher affinity towards SOC and makes stable complexes, thereby decreasing the Cu mobility in soil. Adsorption and precipitation of heavy metals to solid phases and also increasing the negatively charged functional group due to increase in soil pH resulted in reduction of Cu mobility in soil.

  • Researchpp 1596-1608Li, C., Lin, J., Zhao, G., and Zhang, J. (2016). "Windmill palm (Trachycarpus fortunei) fibers for the preparation of activated carbon fibers," BioRes. 11(1), 1596-1608.AbstractArticlePDF

    Activated carbon fibers (ACFs) were prepared by steam activation of windmill palm (WP) (Trachycarpus fortunei) fibers in a nitrogen atmosphere at various temperatures in the 600 to 850 °C range, and their characteristics were investigated. The effects of temperature, in terms of porous texture and surface chemistry, were identified through the use of scanning electron microscopy (SEM), nitrogen adsorption-desorption, mercury intrusion porosimetry (MIP), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. The results showed that the ACFs prepared at relatively high temperatures presented more cracking, collapsed surfaces, and lower yields because of the violent reaction that occurred during the activation process. With increasing temperature, more micropores were generated, and then the number eventually declined because of the conversion of partial micropores into mesopores. The ACFs with the highest special surface area, 1320 m2/g, and total pore volume, 1.416 cm3/g, were obtained at the activation temperature of 850 °C. In addition, graphitic carbon, the main compound on the surface of ACFs, decreased. Conversely, the amount of functional groups containing C-O (except for C-OH) slightly increased with increasing activation temperatures. It was also found that the mesopore volume and methylene blue adsorption of ACFs were highly increased as the temperature increased from 600 to 850 °C. Accordingly, WP fibers are a promising precursor for ACF production.

  • Researchpp 1609-1619Yang, X., Liu, X., Shang, L., Ma, J., Tian, G., and Yang, S. (2016). "Variation of tensile properties of single fibres of Dendrocalamus farinosus bamboo," BioRes. 11(1), 1609-1619.AbstractArticlePDF

    This study investigated the mechanical behavior and the variation of Dendrocalamus farinosus single fibres, which were isolated from fibre bundles using a chemical method. A micro-tester was applied to determine the influence of the age of the bamboo sampled, as well as the longitudinal and radial positions, on three indicators featuring tensile properties at the fibre level. The results indicated that the single fibres had a brittle failure mode, resulting in average tensile strength and tensile modulus (MOE) values of 1.06 and 26.93 GPa, respectively. The differing ages and positions across the whole culm appeared to be minor in relation to their tensile properties, which reached a near-optimal state at 2 years old and remained fairly constant. This work could provide basic-data for further research on bamboo properties and increase attention to a potential supplementary material to moso bamboo in industrial utilization.

  • Researchpp 1620-1633Yue, K., Liu, W., Chen, Z., Lu, X., and Lu, W. (2016). "Investigation of the creep property of fast-growing poplar wood modified with low molecular weight resins," BioRes. 11(1), 1620-1633.AbstractArticlePDF

    Fast-growing poplar wood was modified with low molecular weight urea-formaldehyde resin (UF) at 41.5% concentration or phenol-formaldehyde (PF) at concentrations of 15, 25, and 40%. The physical and mechanical properties were measured, and creep behavior tests were carried out under ambient indoor conditions. The specimens were subjected to 30 and 50% of their maximum bending load. The density, modulus of elasticity, and modulus of rupture of UF-wood increased by 37.16, 45.86, and 28.36%, respectively, and the corresponding increases in 15% PF-specimen were 39.41, 31.80, and 27.74%, respectively. The wood modified with resins exhibited less creep deflection. The relative creep deflections of modified wood were about 0.22, 0.53, 1.22, and 0.32 times those of the untreated specimen at 30% of stress level after 15% PF, 25% PF, 40% PF, and UF were added, respectively. At the lower loading level, the relative creep deflection of the 15% PF specimen was 63.94% that of the 41.5% UF-specimen. Specimens treated with UF at 30 and 50% loading were broken within 120 d and 80 d respectively, whereas the untreated specimen was broken within one month at 50% loading.

  • Researchpp 1634-1646Hosseinihashemi, S. K., HosseinAshrafi, S. K., Goldeh, A. J., and Salem, M. Z. M. (2016). "Antifungal and antioxidant activities of heartwood, bark, and leaf extracts of Robinia pseudoacacia," BioRes. 11(1), 1634-1646.AbstractArticlePDF

    Different solvent fractions (Fs) of water:methanol (1:1 v/v) of heartwood, bark, and leaf extracts of Robinia pseudoacacia were evaluated for their antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method; the antifungal activity against the mycelial growth of Trametes versicolor fungus was also determined. The most active fractions were analyzed for their chemical composition using gas chromatography–mass spectrometry (GC/MS). At higher concentrations (0.016 mg/mL), the values of antioxidant activity were 92.3%, 92.5%, 50.6%, 93.4%, and 96.6%, for heartwood F7 (ethyl acetate fraction), bark F7 (ethyl acetate fraction), leaves F9 (methanol fraction), BHT, and vitamin C, respectively. Among the fractions and concentrations of extracts from heartwood, F7 at 12.5 ppm led to the lowest growth of T. versicolor (22.00 mm); F7 of the bark extract showed good antifungal activity, with lower mycelia growth values reached 11.33, 11.33, and 13.00 mm at concentrations of 12.5, 25, and 50 ppm, respectively. For leaf extracts, F9 showed good antifungal activity at all concentrations, where the values of mycelial growth were 26.00, 25.33, and 28.33 mm at concentrations of 12.5, 25, and 50 ppm, respectively. These results indicated that the fractions of R. pseudoacacia can be a valuable and economic resource for use in antioxidant activity or as an antifungal activity against the growth of T. versicolor.

  • Researchpp 1647-1663Jafarian, H., Demers, C. M. H., Blanchet, P., and Laundry, V. (2016). "Impact of indoor use of wood on the quality of interior ambiances under overcase and clear skies: Case study of the Eugene H. Kruger Building, Québec City," BioRes. 11(1), 1647-1663.AbstractArticlePDF

    This paper explores the potential of wood for improving environmental quality in interior spaces. In northern climate cities where overcast skies predominate, interior spaces may appear gloomy or dull, since natural light is white and uniform. Nevertheless it is observed that wooden surfaces tend to create warmer and brighter spaces under overcast sky conditions. The objectives of this research were twofold. The first was evaluating the quality of wooden spaces under two sky conditions in terms of color, brightness and contrast. The second objective was to investigate daylight quantity of wooden spaces under diffuse and clear sky conditions. The method involved on site-surveys using Photolux, a calibrated photoluminance meter. Data consist of calibrated digital images that were processed to analyze the quality of spaces based on brightness, contrast, and color. The Kruger Building, with its internal wooden architectural structure and decorative indoor panels, was chosen as a site study for this research. Conclusions suggest that knowing the effect of different sky conditions on wooden spaces can help architects and other professionals in designing more comfortable and efficient ambiances. More particularly, this research addresses issues related to the quantitative effects of wood on daylighting distribution, visual comfort and luminance diversity.

  • Researchpp 1664-1671Ravi, K., Schrinner, T., Grossmann, H., Ray, A., and Tandon, R. (2016). "Improving adsorption deinking by identifying the optimum balance between polymer beads and deinking chemistry," BioRes. 11(1), 1664-1671.AbstractArticlePDF

    Ink removal from recovered paper is a very important process in paper and board recycling. The current deinking processes have made obvious contributions to the use of raw materials for the paper and board industries. In contrast to the flotation deinking process, in which small air bubbles are used to remove ink from the pulp, the novel and more energy-efficient method of adsorption deinking technique depends on the attachment and adsorption of ink particles on small polymer beads. The energy savings of adsorption deinking results from the fact that the process is efficient at greater stock consistencies, thus providing water conservation and savings. The present study was carried out to improve the adsorption deinking method by identifying the optimum balance between the deinking chemistry and the polymer beads. Different types of deinking solutions and polymer beads were used for this study with newsprints and mixture of newsprints and magazines. It was found that EGA 3000 solution and polyethylene terephthalate beads worked well with newspaper pulp.

  • Researchpp 1672-1689Kanchanalai, P., Temani, G., Kawajiri, Y., and Realff, M. J. (2016). "Reaction kinetics of concentrated-acid hydrolysis for cellulose and hemicellulose and effect of crystallinity," BioRes. 11(1), 1672-1689.AbstractArticlePDF

    Batch experiments for the hydrolysis of xylan and pure cellulose (Avicel) hydrolysis and the decomposition of xylose and glucose were performed at varying sulfuric acid concentrations in the range of 10 to 50 wt.% and varying temperatures in the range of 80 to 100 °C. Increasing the temperature and acid concentration hastened the hydrolysis and the sugar decomposition rates. The hydrolysis rate of Avicel was much slower than that of xylan because of its crystallinity. The kinetic parameters for the concentrated acid hydrolysis reaction were estimated for both glucose and xylose reaction paths. The effect of initial cellulose crystallinity on the acid hydrolysis rate was also investigated, such that the cellulose was treated with various concentrations of phosphoric acid. A dramatic reduction in the cellulose crystalline index was observed when the phosphoric acid concentration was in a narrow range around 80 wt.%. It was found that the hydrolysis rate significantly increased with the decrease in initial cellulose crystalline index.

  • Researchpp 1690-1706Jiang, G., Zhang, Z., Li, L., Du, F., and Pang, J. (2016). "Analysis of purified oligomeric proanthocyanidins from Larix gmelinii bark and the study of physiological activity of the purified product," BioRes. 11(1), 1690-1706.AbstractArticlePDF

    A simple and efficient method for the purification of oligomeric proanthocyanidins (LOPC) from degreased Larix gmelinii bark was developed. The purity of LOPC was increased from 51.7% to 92.2%, and the cumulative recovery rate was 97.0%. The reversed phase high performance liquid chromatography-mass spectrum (RHPLC-MS) analysis indicated that the percentage contents of catechin (CA), epicatechin (EC), and procyanidin B1 (PB1) in purified LOPC (P-LOPC) were 5.05%, 2.02%, and 0.71%, respectively. The percentage contents of catechin and procyanidin B1 were noticeably higher than those obtained from grape seed extract (2.77% and 0.61%). The average degree of polymerization of P-LOPC was found to be 2.66. The matrix-assisted laser desorption ionization-time of flight/mass spectrum (MALDI-TOF/MS) analysis demonstrated that the dimer was the major component of purified LOPC and the distribution range was from dimer (m/z 713) to decamer (m/z 3016.6). The IC50 values of P-LOPC against DPPH (1,1-diphenyl-2-picryl-hydrazyl), OH (hydroxy radical), and ABTS+ (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt) were 76.4±3.82, 7.92±0.40, and 2.4±0.12. Purified LOPC exhibited more excellent physiological activity than VC (vitamin C), TBHQ (tert-butyl hydroquinone), and pine bark extract.

  • Researchpp 1707-1720Wang, S., Wang, Y., Leng, F., Chen, J., Qiu, K., and Zhou, J. (2016). "Separation and enrichment of catechol and sugars from bio-oil aqueous phase," BioRes. 11(1), 1707-1720.AbstractArticlePDF

    Aiming at obtaining greater value from the complicated composition of the bio-oil aqueous phase, solvents of increasing polarity were employed to sequentially separate the bio-oil aqueous phase using column chromatography. This not only relieved the catalyst deactivation, but also made it possible to obtain fractions rich in different chemical families to produce high-grade liquid fuels and valuable chemicals. Gas chromatography was adopted as a monitoring technology, and 11 fractions rich in different chemical families were obtained. The phenolic compounds in the aqueous phase were primarily eluted using dichloromethane. The strong polar benzenediols were enriched gradually in a dichloromethane fraction, and a high catechol content of 62.81% was achieved with the subsequent combination of a pH control method. Ethyl acetate gave three fractions, and pyrolytic sugars were the predominant compounds, whose highest content reached 67.86% in the third fraction. Further separation of the sugar-rich fraction using column chromatography could remove the residual phenolic compounds and furans and acquire a sugar fraction suitable for fermentation.

  • Researchpp 1721-1728Yu, H., Fang, Q., Cao, Y., and Liu, Z. (2016). "Effect of HCl on starch structure and properties of starch-based wood adhesives," BioRes. 11(1), 1721-1728.AbstractArticlePDF

    Starch-based adhesive was prepared from corn starch and polyvinyl alcohol (PVA) as raw materials by acid hydrolysis with HCl. The starch was hydrolyzed with different amounts of HCl and characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermal gravimetric analysis. The results indicated that different amounts of HCl affected hydrogen bonds, the amount of free hydroxyl groups, crystalline structure, compatibility between starch and PVA, thermal stability, and bond strength. The crystallinity decreased by 13.7% when the amount of acid was 33% compared with untreated starch. The bond strength reached its maximum of 1.35 MPa when the acid content was 23%. The initial decomposition temperature of starch decreased after acid hydrolysis. It was also noted that corrosion of the starch surface increased with increasing acid content.

  • Researchpp 1729-1740Percin, O. (2016). "Determination of screw withdrawal strength of heat-treated and reinforced laminated veneer lumber," BioRes. 11(1), 1729-1740.AbstractArticlePDF

    The withdrawal resistance of screws in heat-treated and reinforced laminated veneer lumber (RLVL) was determined in the radial, tangential, and transverse directions. For this reason, laminated veneer lumber (LVL) and RLVL with carbon fibers were produced from heat-treated oak (Quercus petraea (Liebl.)) veneers using phenol formaldehyde as the adhesive. Wood samples were heat-treated at 140, 170, 200, and 230 °C for 2 h. According to the results of the study, screw withdrawal strength values of LVL increased for heat-treated samples at 140 °C, but decreased at 170, 200, and 230 °C. However, in all groups, the screw withdrawal strength values of the RLVL were higher than those of the LVL. The highest screw withdrawal strength values were identified in the tangential direction, and the lowest were in the transverse directions. Carbon fiber can be used between the heat-treated wood veneers to provide sufficient screw withdrawal strength for use in many different industries.

  • Researchpp 1741-1752Boran, S. (2016). "Mechanical, morphological, and thermal properties of nutshell and microcrystalline cellulose filled high-density polyethylene composites," BioRes. 11(1), 1741-1752.AbstractArticlePDF

    Effects of nutshell fiber loadings of 30 wt.% and MCC loadings up to 15 wt.% on some properties of high-density polyethylene composites (HDPE) were investigated. The composites were manufactured by a single screw extruder and injection molding. The experimental composite samples were tested for their mechanical performance including tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength. Thermal and morphological properties of the composites were tested by differential scanning calorimetry-DSC and scanning electron microscopy (SEM), respectively. The maximum tensile strength was obtained from the MCC-filled composites, whereas the maximum flexural strength was achieved with the MCC-nutshell filled composites. The tensile and flexural moduli of the composites were significantly improved with increasing MCC content and the presence of nutshell fibers in polymer matrix. Impact strength decreased using MCC and nutshell fiber in the polymer matrix. Based on the DSC results, there was no remarkable change in the melting point for all composites. The results showed that the incorporation of nutshell fibers and MCC in the polymer matrix had brought about some positive effect on mechanical properties of HDPE composites.

  • Researchpp 1753-1764Lafond, C., Blanchet, P,. Landry, V., Galimard, P., and Ménard, S. (2016). "The effects of acrylate impregnation of black spruce timber as connectors strength," BioRes. 11(1), 1753-1764.AbstractArticlePDF

    Chemical impregnation of black spruce was conducted to enhance the wood embedment capacity. The formulation was made of 1,6 hexanediol diacrylate, trimethylpropane triacrylate, and a polyester acrylate oligomer. A second formulation, same as the first but with 1% wt of SiO2 nanoparticles, was selected to investigate the potential of nanoparticles and to improve the efficiency of the treatment. The wood embedment capacity was carried out by a dowel-bearing test, which was performed for the two treatments and for an untreated wood group. Both treatments showed an increase of strength of nearly 50% when compared to untreated samples. Micrograph views revealed that the impregnation solution penetrated into the wood only up to 100 μm. Hence, with low chemical consumption, the structural bearing capacity can be significantly increased.

  • Researchpp 1765-1783Wang, S., Sun, Y., Kong, F., Yang, G., and Fatehi, P. (2016). "Preparation and characterization of lignin-acrylamide copolymer as a paper strength additive," BioRes. 11(1), 1765-1783.AbstractArticlePDF

    With currently practiced technology, lignin is either incinerated in the recovery cycle of pulping or wasted in wastewater treatment systems, resulting in its underutilization. However, lignin can be converted to value-added products. In this work, the copolymerization of soda lignin (SL) and acrylamide (AM) was carried out using potassium persulphate (K2S2O8) as an initiator in an aqueous solution to prepare water-soluble lignin-acrylamide (SL-AM) copolymer as a dry strength additive. The results showed that the optimal copolymerization conditions were 7.5 AM/SL molar ratio, 3.0 wt.% (based on lignin) of K2S2O8, 90 °C, and 4 h of reaction time, which resulted in a SL-AM copolymer with 100% solubility at 10 g/L concentration at pH 7 in water, a grafting ratio of 398%, and a molecular weight of 1.94×105 g/mol. The prepared SL-AM copolymer was characterized by elemental analysis, Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (H-NMR) spectroscopy, and thermogravimetric analysis (TGA). By adding 1.0 wt.% of SL-AM copolymer to the pulp, the tensile, tear, and burst strengths were increased by 23.1%, 22.7%, and 15.2%, respectively, which implies that the resultant copolymer was an effective strength additive for papermaking.

  • Researchpp 1784-1795Deng, J., Chen, F., Wang, G., and Zhang, W. (2016). "Variation of parallel-to-grain compression and shearing properties in moso bamboo culm (Phyllostachys pubescens)," BioRes. 11(1), 1784-1795.AbstractArticlePDF

    As an abundant natural resource in Asia, bamboo is receiving increased attention as an engineering material due to its renewability and excellent strength. The parallel-to-grain compression and shearing properties of moso bamboo culm were examined. The growth characteristics (bamboo age, nodes, and location along the culm), as well as treatments for practical applications (hole punching and hoop reinforcing by hose clamp) were investigated for their influence. Mechanical tests were conducted in accordance with the ISO22157-1:2004 (2004), ISO/TR 22157-2:2004(E) (2004), and CNS GB/T 15780-1995 (1996) standards. Acceptable loading rates for the parallel-to-grain compression and shearing tests were 0.1 and 0.05 mm/s, respectively. The compressive and shearing strengths increased from the bottom to the top of the bamboo. Bamboo age and nodes exerted little influence on parallel-to-grain compressive and shearing strength. In addition, hole punches diminished the mechanical strength of the bamboo culm, while hose clamps enhanced it slightly.

  • Researchpp 1796-1807Chen, T., Liu, J., Wu, Z., Wang, W., Niu, M., Wang, X., and Xie, Y. (2016). "Evaluating the effectiveness of complex fire-retardants on the fire properties of ultra-low density fiberboard (ULDF)," BioRes. 11(1), 1796-1807.AbstractArticlePDF

    The preparation conditions of complex fire-retardant (FR) agents containing boron compounds (BF, X1), nitrogen-phosphorus compounds (NPF, X2), silicon compounds (SF, X3), and halogen compounds (HF, X4) for ultra-low density fiberboard (ULDF) were optimized using a response surface methodology. The effects and interactions of X1, X2, X3, and X4 on the fire properties of ULDF were investigated. An optimum char yield of 61.4% was obtained when the complex fire-retardant agents contained 33.9% boron, 27.2% nitrogen-phosphorus, 15.0% silicon, and 28.6% halogen. Compared with control fiberboard (CF), the heat release rate (HRR) profiles of all fiberboards with FRs were reduced. The peak HRR reduction in BF and NPF was more pronounced than for SF and HF at this stage. And the mixed fiberboard (MF) had the lowest pkHRR of 75.02 kW m−2. In total heat release (THR) profiles, all fiberboards with FRs were lower than the CF. Unlike the HRR profiles, HF had the lowest THR profile of 15.33 MJ m−2. Additionally, Si compounds showed greater effectiveness in preventing ULDF mass loss than BF, NPF, and HF. MF showed the highest residual mass (40.94%). Furthermore, the synergistic effect between four FR agents showed more significant results in ULDFs.

  • Researchpp 1808-1827Vänskä, E., Vihelä, T., Johansson, L. S., and Vuorinen, T. (2016). "Addition of ascorbic acid of purified kraft lignin in pulp refining: Effects on chemical characteristics, handsheet properties, and thermal stability," BioRes. 11(1), 1808-1827.AbstractArticlePDF

    The effects of two pulp pretreatments, impregnation with ascorbic acid (AA) or purified kraft lignin (KL), on bleached pulp refining were investigated by examining and testing handsheets made from these pulps. The AA pretreatment of the pulp amplified the depolymerization of the cellulose and notably impaired the strength properties of the pulp handsheets. The effects were enhanced upon the combination of the AA pretreatment and intensive refining. Furthermore, heat treatments (at 225 °C, 30 min, in water vapor atmospheres of 1 and 75% (v/v)) promoted the depolymerization of cellulose and the total color difference in the AA impregnated handsheets more than for the KL impregnated and reference handsheets. In contrast to AA, the KL pretreatment of the pulp improved the burst index stability of the refined pulp handsheets after the humid thermal treatment (75% (v/v)). In addition, the total color difference of the KL impregnated handsheets was lower than the AA impregnated and reference handsheets.

  • Researchpp 1828-1842Norambuena, M., Vidal, C., Carrasco, L., Reyes, P., Parra, C., Contreras, D., and Mendonça, R. T. (2016). "Optimization of experimental variables to modify lignin from Eucalyptus globulus under alkaline catalysis," BioRes. 11(1), 1828-1842.AbstractArticlePDF

    Conditions to increase phenolic hydroxyl groups (OH-Phe) in organosolv lignin using alkaline catalysts (NaOH and KOH) were optimized with the purpose of increasing the reactivity of lignin and to evaluate the effect on the structure of the newly generated compounds as a result of the base-catalyzed depolymerization (BCD). The lignin-derived compounds could be used for the synthesis of bio-based polymers and nanomaterials. The maximal yield of OH-Phe reached values of 5270 and 3970 μmol per gram of lignin when NaOH (8.6%, 173 °C, and 33 min) and KOH (11.7%, 174 °C, and 58 min), defined as optimal conditions for BCD, were used, respectively, while for the control lignin, OH-Phe was 2830 μmol per gram of lignin. The molecular weight (Mw) and glass transition temperature (Tg) for lignin-NaOH were lower than those of lignin-KOH and lignin-control. Both lignin derivatives had greater thermal stability at high temperatures than lignin-control. In conclusion, the results showed higher modifications in the structure of lignin as a result of the oxidation process, primarily by cleavage of the β-O-4 ether bond and variations in thermochemical properties when NaOH is used as alkaline catalyst.

  • Researchpp 1843-1854Liu, Q., Tan, J., Cai, C., Ma, L., and Wang, T. (2016). "Enhanced sugar alcohol production from cellulose by pretreatment with mixed ball-milling and solid acids," BioRes. 11(1), 1843-1854.AbstractArticlePDF

    Efficient pretreatment is the key step in catalytic biomass conversion. Herein, a mixed ball-milling method was used to pretreat cellulose with a solid catalyst. The method was tested with solid acid and commercial 5 wt% Ru/C in water, and the effect of pretreatment on yield was measured by the hydrolytic-hydrogenation of cellulose to sugar alcohols, which are the platform compounds for the production of gasoline and fine chemicals. The influence of ball-milling mode, time, and reaction parameters was studied. The properties of cellulose and the catalyst were also analyzed before and after treatment. The yield of sugar alcohols reached 90.3% at 463 K with amorphous zirconium phosphate (ZrP) and Ru/C and a mixed ball-milling time of 2 h. The high sugar alcohol yield was achieved 12 times faster than with the single ball-milling method under the same reaction conditions for 24 h. This effect is ascribed to the enhanced contact between cellulose and catalyst, which promotes the rate-determined cellulose depolymerization to obtain high sugar alcohols yield.

  • Researchpp 1855-1867Groche, P., and Huttel, D. (2016). "Paperboard forming - specifics compared to sheet metal forming," BioRes. 11(1), 1855-1867.AbstractArticlePDF

    Growing demand for sustainable products has led to increased interest in the use of paperboard as a structural material. Paperboard products are almost exclusively manufactured by embossing, pulp molding, and bending processes. Other well-known forming methods, such as deep or stretch drawing, are only rarely applied to paperboard. This is primarily ascribed to the lack of knowledge concerning the process design and limits when paperboard is employed. In the present work, the applicability of well-established design strategies and characterization methods for metals to paperboard is investigated. Therefore, forming limit diagrams for paperboard are determined in a first step. Additionally, significant material parameters are identified in order to describe the material influence upon the forming limit. Furthermore, the influence of a hydrostatic counter pressure onto the forming limit is investigated. To predict the forming behaviour of a complex formed paperboard demonstration part, a numerical model of a hydroforming process is set up, executed, and validated.

  • Researchpp 1868-1881Wang, S., and Jing, Y. (2016). "Effects of a chitosan coating layer on the surface properties and barrier properties of kraft paper," BioRes. 11(1), 1868-1881.AbstractArticlePDF

    Biodegradable chitosan can be applied as a coating on the surface of kraft paper in order to improve its barrier properties against water vapor and air. The food packaging industry can benefit from the addition of chitosan to its current packaging, and in turn reduce pollution from plastic packaging plants. This paper discusses the film formation of chitosan, the permeability of paper coated with a chitosan layer, and the influence on the paper’s surface and barrier properties under different process conditions. SEM (scanning electron microscope), AFM (atomic force microscope), ATR-FTIR (Fourier transmission infrared spectroscope with attenuated total reflection), and PDA (penetration dynamics analysis) were used to analyze the properties of chitosan’s film formation and permeability. A controlled experiment showed that the chitosan layer was smoother than the surface of the uncoated kraft paper, had better film formation, and that there was no chitosan penetration through the kraft paper. The barrier properties against water vapor were strongest when there was a higher concentration of chitosan solution at the optimum pH, stirring speed, and those with a thicker coating on the kraft paper.

  • Researchpp 1882-1891Li, X., Wang, X., and Zhang, M. (2016). "Molecular dynamics of water in wood studied by fast field cycling nuclear magnetic resonance relaxometry," BioRes. 11(1), 1882-1891.AbstractArticlePDF

    Water plays a very important role in wood and wood products. The molecular motion of water in wood is susceptible to thermal activation. Thermal energy makes water molecules more active and weakens the force between water and wood; therefore, the water molecules dynamic properties are greatly influenced. Molecular dynamics study is important for wood drying; this paper therefore focuses on water molecular dynamics in wood through fast field cycling nuclear magnetic resonance relaxometry techniques. The results show that the spin-lattice relaxation rate decreases with the Larmor frequency. Nuclear magnetic resonance dispersion profiles at different temperatures could separate the relaxation contribution of water in bigger pores and smaller pores. The T1 distribution from wide to narrow at 10 MHz Larmor frequency reflects the shrinkage of pore size with the higher temperature. The dependence of spin-lattice relaxation rate on correlation time for water molecular motion based on BPP (proposed by Bloembergen, Purcell, and Pound) theory shows that water correlation time increases with higher temperature, and its activation energy, calculated using the Arrhenius transformation equation, is 9.06±0.53 kJ/mol.

  • Researchpp 1892-1904García-Gonzalo, E., Santos, A. J. A., Martínez-Torres, J., Pereira, H., Simões, R., García-Nieto, P. J., and Anjos, O. (2016). "Prediction of five softwood paper properties from its density using support vector machine regression techniques," BioRes. 11(1), 1892-1904.AbstractArticlePDF

    Predicting paper properties based on a limited number of measured variables can be an important tool for the industry. Mathematical models were developed to predict mechanical and optical properties from the corresponding paper density for some softwood papers using support vector machine regression with the Radial Basis Function Kernel. A dataset of different properties of paper handsheets produced from pulps of pine (Pinus pinaster and P. sylvestris) and cypress species (Cupressus lusitanica, C. sempervirens, and C. arizonica) beaten at 1000, 4000, and 7000 revolutions was used. The results show that it is possible to obtain good models (with high coefficient of determination) with two variables: the numerical variable density and the categorical variable species.

  • Researchpp 1905-1918Lai, C., Li, X., Zhu, J., Yu, S., and Yong, Q. (2016). "Detoxification of steam-exploded corn stover prehydrolyzate with organobentonite enhances ethanol fermentation by Pichia stipitis," BioRes. 11(1), 1905-1918.AbstractArticlePDF

    The inhibitors derived from degradation of lignocellulose have adverse impacts on fermentation, which is considered to be a fundamental problem in bioethanol production. Fermentation of steam-exploded corn stover prehydrolyzate by Pichia stipitis showed that phenolic compounds had much higher inhibitory effects than weak acids and furan at high fermentation pH. Two types of organobentonite (cetyltrimethylammonium (CTMA)- and benzyltrimethylammonium (BTMA)-modified bentonite) were used to remove phenolic compounds in prehydrolyzate. The effectiveness of organobentonite treatment was evaluated by ethanol fermentation, which indicated that the organobentonite treatment improved the fermentability substantially, even though a noticeable difference was found in the phenol removal by the two organobentonites. Without organobentonite treatment, the sugar utilization ratio was only 68.1%, and the produced ethanol was 15.36 g/L. After CTMA- and BTMA-bentonite treatment, the sugar utilization ratios were beyond 95%; meanwhile, the ethanol production increased by 45.5% and 42.8%, respectively. This indicated that organobentonite treatment was a potential detoxification method.

  • Researchpp 1919-1929Li, R., Zhang, B., Xiu, S., Wang, H., Boaten, N. A. B., Holmes, B. M., Wang, L., and Shahbazi, A. (2016). "Characteristics of pine gasification ash and its effects on Chlamydomonas debaryana growth," BioRes. 11(1), 1919-1929.AbstractArticlePDF

    Large amounts of ash, generated from biomass gasification, often contaminate syngas and the ecosystem. This study showed that the ash obtained from the gasification of pine wood was primarily composed of carbon (15% to 25%), minerals (~21%), and oxygen (52% to 63%), and exhibited low surface area (8.4 to 11.2 m2/g). The size of ash particles was between 600 nm and 600 μm. Calcium, potassium, and sodium were the three most common mineral elements in the ash. Leaching tests showed that adding ash to water raised the pH value from 5.7 to between 11.2 and 11.5, and, as time progressed, more mineral elements were released from the ash. For growing microalga Chlamydomonas debaryana in media containing ashes, no toxicity of pine ash was found.

  • Researchpp 1930-1940Soltani, M., Rohani, A. A., Ramazani, O., Naji, H. R., Hazandy, A. H., Simonot, L., and Bakar, E. S. (2016). "UV-curable coating process on CMYK-printed duplex paperboard, part II: Effects of nano-TiO2 modification," BioRes. 11(1), 1930-1940.AbstractArticlePDF

    The influence of TiO2 nano-particles (nano-TiO2) was studied relative to the mechanical and optical properties of CMYK printed paperboard after coating with a UV-curable varnish. Commercial duplex paperboard (glazed grayback paperboard, 230 g/m2) was printed with a CMYK offset printing process. Board samples were coated with a nano-TiO2 modified UV-curable varnish at four treatment levels (0, 0.2, 0.5, and 1%) using an industrial screen-coating machine. The samples were then dried using a UV lamp in an industrial UV drying machine. Sample discoloration was measured spectrophotometrically using CIELab parameters (L*, a*, b*, and ΔE) before and after coating. The whiteness, brightness, fold, and tear resistance of the ink films were also measured. The nano-treatment had a significant effect on the relative optical parameters, which resulted in increasing the lightness of the treated samples. Color change (ΔE) was recorded for all tested samples, and an unperceivable change was observed in case of the nano-treatment with 0.2% as the end value. The weakly perceivable changes were found in the cases of treatment with 0.5 and 1% nano-intensities. The nano-TiO2 treatment significantly improved the fold and tear resistance of the samples.

  • Researchpp 1941-1950Li, J., Yuan, Y., and Guan, X. (2016). "Assessing the environmental impacts of glued-laminated bamboo based on a life cycle assessment," BioRes. 11(1), 1941-1950.AbstractArticlePDF

    The bamboo industry plays a significant strategic role in the world’s economy. Laminated bamboo, with increasing yearly yields, is the intermediate material for bamboo products such as furniture, floor board, and container floor. The trilaminar straight joint glued-laminated bamboo production line is the leading enterprise in Fujian Province, and it was used to conduct a load analysis of the data collected from a year’s production, based on the life cycle assessment system. The results show that the processing of glued-laminated bamboo contributes notably to the acidification potential, eutrophication potential, global warming potential, and photochemical ozone creation potential, whereas resource depletion and ozone depletion are affected by the urea-formaldehyde resin adhesive, among which the urea contributes the most. As for processing, carbonization, desiccation, and thermo-compression, these have the greatest impacts on the environmental load, with a total contribution rate of greater than 67%, as the main source for the power depletion is from the processing of fossil fuel. In addition, the oxynitride, phosphide, sulfide, aromatic hydrocarbon, etc., that are discharged from the reaction intensify the eutrophication potential, the photochemical ozone creation potential, and the acidification potential.

  • Researchpp 1951-1958Zhao, Z., Ma, Q., He, Z., and Yi, S. (2016). "Effects of frequency and processing time on the drying course of ultrasound-assisted impregnated wood," BioRes. 11(1), 1951-1958.AbstractArticlePDF

    Impregnating wood, assisted with ultrasound technology, could improve the impregnation efficiency by improving the permeability of wood, thus affecting the subsequent drying process. Poplar lumber and phenolic resin were applied to investigate the influence of ultrasound-assisted impregnation on the wood drying process. The ultrasonic frequency and processing time were analyzed and correlated. The results indicated that the average drying rate of impregnated wood was generally faster in the earlier stage and slower in the later period than the blank group. At the earlier drying stage, the drying rate exhibited a decreasing tendency with increasing ultrasonic time, as the frequency remained constant. However, with an unaltered processing time, a contrary trend was detected as the frequency was increased. The ultrasonic frequency and time caused an complex effect on the average drying rate during the later drying course. These findings could be applied to the impregnated wood drying industry to strike a balance between ultrasound-assisted performance and the related drying effectiveness.

  • Researchpp 1959-1970Hua, W., Liu, C., Wu, S. B., and Li, X. H. (2016). "Analysis of structural units and their influence on thermal degradation of alkali lignins," BioRes. 11(1), 1959-1970.AbstractArticlePDF

    The chemical structures of four alkali lignins isolated from poplar, fir, straw, and bagasse were investigated. To explore the relationship between the structural units and the thermal decomposition behavior, the system was tested by elemental analysis, Fourier transform infrared spectrometry, thermogravimetric analysis (TGA), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The results indicated that the carbon content of poplar lignin (PL) was higher than that of others. Fir lignin (FL) exhibited the highest guaiacol units, while the other three lignins were abundant in syringol units. The thermal decomposition characteristics and pyrolysis products of the four lignins were influenced by the material structural and composition. The DTG curves showed that the initial temperatures and major degradation temperatures of woody lignins(FL and PL) with complex inherent structures were shifted to the high temperature zoom compared with that of non-woody (BL and SL)lignins. Py-GC/MS analysis showed that guaiacol-type phenolic compounds were predominant pyrolysis products derived from the four lignins. The yield of guaiacol-type phenols could reach 82.87%. Moreover, the BL had selectively on phenol-type compounds with yield of 27.89%.

  • Researchpp 1971-1981Abd Razak, S. I., Wahab, I. F., Abdul Kadir, M. R., Md Khudzari, A. Z., Mohd Yusof, A. H., Dahli, F. N., Mat Nayan, N. H., and Anand, T. J. S. (2016). "Biomimetic growth of hydroxyapatite on kenaf fibers," BioRes. 11(1), 1971-1981.AbstractArticlePDF

    Biomimetic hydroxyapatite (HA) growth on mercerized kenaf fiber (KF) was achieved by immersion in a simulated body fluid (SBF) solution with the addition of a chelating agent. An electron micrograph revealed uniform HA layers on the KF within 14 days of immersion with significant vibrational peaks of HA components. The tensile tests showed no significant drops in the unit break of the modified fibers. This new bone-like apatite coating on KF can be useful in the field of bone tissue engineering. The key motivation for this new approach was that it utilizes the abundantly available kenaf plant resource as the biobased template.

  • Researchpp 1982-1990Choi, C., Lee, C., Yoo, J., Yang, S., and Kang, S. (2016). "Improvement of biodegradation of wood plastic composites using rice-bran mixture," BioRes. 11(1), 1982-1990.AbstractArticlePDF

    Wood-plastic composites (WPCs) are currently discarded using incineration treatment, which is very expensive. Hence, this study was performed to improve the biodegradation of WPCs, such that they could potentially be buried after use, and to estimate their bending strength. A biodegradation test (determining the ultimate aerobic biodegradability of plastic materials under controlled composting conditions) was performed according to ISO 14855-1. Two groups of specimens were prepared using rice-bran mixture as the bioresource. One group contained rice-bran mixtures of 5, 7.5, and 10 wt.% instead of wood flour contents, and another group contained rice-bran mixtures of 8, 16, and 24 wt.% instead of the talc component. During the 20 days of the biodegradation experiment, the WPC (control) showed 18% biodegradation, and 7.5%-rice-bran-mixture-added specimen showed the highest biodegradation of 32%. Furthermore, the bending strength (MOR) was increased by up to 140% by adding rice-bran mixture as a biodegradable component. Therefore, the rice-bran mixture improved the biodegradation and mechanical properties of WPCs.

  • Researchpp 1991-2006Diong, K. C., Ngoh, G. C., and Chua, A. S. M. (2016). "Transformation of starchy lignocellulosic biomass to ethanol using ragi tapai synergized with microwave irradiation pretreatment," BioRes. 11(1), 1991-2006.AbstractArticlePDF

    Ethanol production strategy was studied using multiple strain microbes from microwave irradiation (MI) pretreated sago waste. Sago waste (SW) was MI-pretreated for reducing sugars production using 2 heating media (water and sulfuric acid) under pretreatment conditions including MI power, pretreatment duration, and solid loading. When water was used, the pretreatment parameters were optimized using Box-Behnken Design (BBD). However, gelatinized starch and charring of SW led to an insignificant quadratic model. To mitigate the gelatinization problem while determining the best MI pretreatment conditions, water was substituted by sulfuric acid using single factor method. The highest reducing sugar yield of 261.5 mg/g SW was achieved at 7.5% solid loading, 6 min pretreatment duration, and 300 W MI power. The effectiveness of the pretreatment was ascertained by field-emission scanning electron microscopy (FESEM) and chemical-composition analysis. When fermenting MI-pretreated SW using ragi tapai, simultaneous saccharification of starch and ethanol production was evidenced from the sugar/ethanol profile. A resulted yield of 7.24 g ethanol/100 g SW confirmed the fermentability of MI-pretreated SW. The ethanol production was well fitted into the modified Gompertz model.

  • Researchpp 2007-2019Duchesne, I., Vincent, M., Wang, X., Ung, C. H., and Swift, D. E. (2016). "Wood mechanical properties and discoloured heartwood proportion in sugar maple and yellow birch grown in New Brunswick," BioRes. 11(1), 2007-2019.AbstractArticlePDF

    Rising interest in using wood in non-residential multi-story building structures opens up new opportunities for utilising low-grade hardwoods. The primary objective of this study was to evaluate the geographic variation in modulus of elasticity (MOE) and modulus of rupture (MOR) of sugar maple and yellow birch wood in relation to stand and tree characteristics for two regions in New Brunswick, Canada. Mixed effects statistical models were developed to test the effects of stand, tree, and wood sample variables. A second objective was to examine geographic variation in heartwood discolouration in relation to stand and tree characteristics. Between-tree differences (trees nested within sites) accounted for 44% and 35% of the total variation in yellow birch (MOE and MOR, respectively) and for 69% and 60% of total variation in sugar maple. The fixed effects explained only a very small part for the variation in MOE and MOR in the sugar maple data (10% for MOE and 5% for MOR). For sugar maple, mechanical properties (MOE and MOR) at 50% of the radius were considerably lower than those close to the bark, but this radial variation was not noteworthy for yellow birch. Discoloured heartwood proportion had no significant effect on wood mechanical properties.

  • Researchpp 2020-2029Figueiredo, A. B., Magina, S., Evtuguin, D. V., Cardoso, E. F., Ferra, J. M., and Cruz, P. (2016). "Factors affecting the dimensional stability of decorative papers under moistening," BioRes. 11(1), 2020-2029.AbstractArticlePDF

    A crucial problem for laminate producers is the dimensional instability of decorative papers during soaking in aqueous solutions, but the source of this dilemma is not completely understood yet. In this study, eight commercial decorative papers of similar fiber composition and sizing were analyzed for their structural, physical, and mechanical properties. These properties were examined for their correlations to the dimensional stability of papers when moistened, as assessed by the wet stretch dynamics. Structure-to-property relationships were evaluated by principal component analysis (PCA). Within the set of parameters examined, PCA revealed that fiber orientation and the content of fillers/pigments influenced the wet expansion of paper web and affected its margins and dimensions in longitudinal and transverse directions of the paper machine. These variables are discussed within the context of decorative paper engineering in order to produce high performance papers with regular wet expansion properties.

  • Researchpp 2030-2042Chang, X. F., Luukkonen, A., Olson, J., and Beatson, R. (2016). "Pilot-scale investigation into the effects of alkaline peroxide pre-treatments on low-consistency refining of primary refined softwood TMP," BioRes. 11(1), 2030-2042.AbstractArticlePDF

    Primary refined coarse softwood thermomechanical pulp was treated with alkaline peroxide prior to low-consistency (LC) refining. The effects of the pre-treatments on pulp quality, refinability, and electrical energy consumption were assessed. Four pre-treatments were conducted with alkali charges of 2.5 and 6% and peroxide charges of 3 and 4%. The pulps were refined to specific energies up to 600 kWh/t by multiple passes through an LC refiner at intensities of 90 and 150 kWh/t. It was found that alkaline peroxide treatments increased tear strength and protected the fibre from cutting, especially during high intensity refining below a specific energy of 300 kWh/t. Treatment with 6% NaOH and 4% or 3% H2O2 led to lower brightness gains and scattering coefficients but increased the tensile strength index by 31%, potentially lowering the total electrical energy required to achieve strong pulp. The enhancement of tensile strength caused by the highly alkaline peroxide mostly resulted from increased bonding, which was attributable to acid group generation rather than the promotion of further fibrillation during LC refining.

  • Researchpp 2043-2054Guo, T., Liu, Y., Liu, Y., Yang, G., Chen, J., and Lucia, L. A. (2016). "Chemical elucidation of structurally diverse willow lignins," BioRes. 11(1), 2043-2054.AbstractArticlePDF

    A new fast-growing wood raw material, willow (Salix matsudana cv. Zhuliu), was subjected to pulping to identify the structure of its lignin. Thus, the black liquor lignin (AL) and enzymatic mild acidolysis lignin (EMAL) were prepared, and their molecular structure and molecular weight of the isolated lignin polymers were comprehensively investigated by Fourier transform infrared spectroscopy (FT-IR), two-dimensional nuclear magnetic resonance (2D-NMR HSQC), 13C nuclear magnetic resonance (13C-NMR), and gel permeation chromatography (GPC). The NMR results showed that syringyl (S) unit was the predominant structural monomeric unit in willow lignin, as opposed to guaiacyl (G) and p-hydroxyphenyl (H) units. The S/G ratio for the EMAL was found to be 2.02, whereas that for the AL was 0.94. The lignin in the black liquor (AL) fraction was modified during pulping, as shown by its reduced molecular weight. The two isolated lignin polymers, EMAL and AL showed low weight-average molecular weight: 4127 g/mol and 3522.5 g/mol, and in addition they exhibited low polydispersity index (Mw/Mn < 2.0).

  • Researchpp 2055-2070Saffian, H. A., Abdan, K., Hassan, M. A., Ibrahim, N. A., and Jawaid, M. (2016). "Characterisation and biodegradation of poly(lactic acid) blended with oil palm biomass and fertiliser for bioplastic fertiliser composites," BioRes. 11(1), 2055-2070.AbstractArticlePDF

    This work presents a new technique for producing a slow-release fertiliser with bioplastic polymer coating. Poly(lactic acid) (PLA) was blended with granular NPK fertiliser and empty fruit bunch (EFB) fibres using extrusion technique. The polymer coatings were characterised using thermal gravimetric analyser (TGA) and diffraction scanning calorimetry (DSC). The PLA and EFB fibres complemented each other in terms of their thermal stability in the BpF composites. A homogenous BpF blend was observed under a scanning electron microscope (SEM). In biodegradation the percentages of weight loss for PLA/EFB/NPKC1 and PLA/EFB/NPKC2 were higher due to the presence of EFB fibres, which were 64.3% and 76.3%, respectively.

  • Researchpp 2071-2082Shang, L., Jiang, Z., Liu, X., Tian, G., Ma, J., and Yang, S. (2016). "Effect of modification with methyl methacrylate on the mechanical properties of Plectocomia kerrana rattan," BioRes. 11(1), 2071-2082.AbstractArticlePDF

    This study aims to evaluate the mechanical properties of rattan/polymer composites prepared by polymerization with methyl methacrylate (MMA). The P. kerrana rattan samples were impregnated in a vacuum system and polymerized in an oven at 60 °C for 8 h, using 0.5 wt.% of azobisisobutyronitrile as a catalyst. The macro-mechanical properties of the treated and untreated samples were analyzed. The bending modulus and strength of the treated rattan increased by 206% and 215%, respectively. Additionally, the compressive modulus and strength increased by 109% and 107%, compared to untreated rattan. Scanning electron microscopy (SEM) images showed that MMA penetrated the cell lumen. Furthermore, Fourier transform infrared spectroscopy (FTIR) analysis revealed that MMA diffused into the parenchyma and vessels, but it was not found in the fiber wall. Thus, it can be inferred that the improvement in the mechanical properties of treated rattan was mainly caused by the strengthened parenchyma and vessels. Modification with MMA was shown to be an effective way to enhance the macro-mechanical properties of P. kerrana.

  • Researchpp 2083-2095Fidan, M. S., Yaşar, Ş. Ş., Yaşar, M., Atar, M., and Alkan, E. (2016). "Combustion characteristics of impregnated and surface-treated chestnut (Castanea sativa Mill.) wood left outdoors for one year," BioRes. 11(1), 2083-2095.AbstractArticlePDF

    Treating wood with impregnating materials in order to improve resistance to burning is a commonly employed safety measure. In this study, chestnut (Castanea sativa Mill.) wood samples were impregnated using either Tanalith-E or Wolmanit-CB according to ASTM-D 1413-76 and surface-treated using water-based or synthetic varnish according to ASTM-D 3023. These samples were used to investigate the combustion characteristics of samples left outdoors for one year as detailed in ASTM-E 160-50. The combustion temperatures of the samples left outdoors were similar upon impregnation with either Tanalith-E or Wolmanit-CB. However, the combustion temperature of the samples treated with synthetic varnish was lower than those that were treated with water-based varnish. The time to collapse and the total duration of combustion of the samples left outdoors were shorter for those impregnated with Wolmanit-CB. Weight loss of the samples left outdoors was higher for those that were impregnated with Tanalith-E and treated with water-based varnish. Gas analysis of the samples that were left outdoors indicated that the O2 content of flue gas from samples that were impregnated with Wolmanit-CB and treated with synthetic varnish was high and the CO content of flue gas from the same samples was low.

  • Researchpp 2096-2108Li, X., Luo, X., Dou, L., and Chen, K. (2016). "Preparation and characterization of K2CO3-activated kraft lignin carbon," BioRes. 11(1), 2096-2108.AbstractArticlePDF

    A series of activated carbons (ACs) were prepared by K2CO3 activation from kraft lignin (KL) that was recovered from papermaking black liquor. The effects of process parameters such as the activation temperature (AT), activated period, K2CO3 to KL mass ratio, and N2 flow rate on the characteristics of the final product were determined. The ACs were characterized using nitrogen adsorption, morphology, and fractal dimension analyses. The results showed that the AT was the main factor influencing the yield, surface area, and pore structure. The yield of ACs obviously decreased from 50.6% to 20.5% with increasing AT from 600 °C to 1000 °C, and decreased with increasing K2CO3/KL mass ratio. Activation time and N2 flow rate had slight effect on the yield of ACs. The surface area and total pore volume increased as the AT rose to 900 °C and then decreased with further increases in temperature. The maximum surface area and total pore volume were 1816.3 m2/g and 1.26 cm3/g, respectively, at a K2CO3 to KL mass ratio of 3:1, AT of 900 °C, activation time of 2 h, and N2 flow rate of 70 cm3/min. The pore structure of the ACs could be tailored by controlling the AT. As the AT was increased from 700 to 1000 °C, the mesoporosity increased from 11.6% to 95.9%. SEM images indicated that the morphology of ACs was modified by the AT. The K2CO3 was partially recycled.

  • Researchpp 2109-2123Ran, J., Fu, F., Qin, C., Zhang, P., Yang, L., Wang, W., and Yang, L. (2016). "Evaluation of CuO/MgAl2O4 in biomass chemical looping gasification with oxygen uncoupling," BioRes. 11(1), 2109-2123.AbstractArticlePDF

    Chemical looping gasification (CLG) is a promising method for the utilization of biomass to produce syngas. However, its realization is largely dependent on the use of an oxygen carrier with a high and stable reactivity in cyclic reduction and oxidation. This work focused on the improvement of reactivity and stability of CuO in chemical looping gasification via the addition of MgAl2O4 as an inert material. First, the stability and reactivity of synthesized Cu-based oxygen carriers were studied in a thermogravimetric analyzer (TGA). Then, the characteristics of CLG of biomass and the oxygen carrier in syngas production were investigated by testing gas components, syngas production, and oxygen carrier sintering performance. The results show that CuO supported on MgAl2O4 has a better capacity for oxygen release than pure CuO and a superior stability and gasification activity in the cyclic chemical looping gasification with biomass. A higher operating temperature led to the production of more syngas from biomass gasification with CuO/MgAl2O4 as the oxygen carrier, particularly for CO and H2. CuO/MgAl2O4 also demonstrated a much better effect on methane reforming in CLG. It is believed that CuO/MgAl2O4 is a suitable oxygen carrier for the chemical looping with oxygen uncoupling (CLOU) and CLG of biomass.

  • Researchpp 2124-2137Wei, X., Zhou, S., Huang, Y., Huang, J., Chen, P., Wang, Y., Zhang, X., Tu, Y., Peng, L., and Xia, T. (2016). "Three fiber crops show distinctive biomass saccharification under physical and chemical pretreatments by altered wall polymer features," BioRes. 11(1), 2124-2137.AbstractArticlePDF

    Jute, kenaf, and ramie are important fiber crops in the textile industry, but their core stalks have not been well used. In this study, three fiber crops were examined with enhanced hexoses yields (% cellulose) up to 4.8-, 3.6-, and 1.9-fold from enzymatic hydrolysis of the steam-exploded stalks. Sequential dilute acid/alkali pretreatments achieved the increased hexoses yields up to 7.6-, 4.8-, and 2.8-fold. Without steam explosion, the three crops could increase hexoses yields under extremely high concentrations of NaOH (12% to 16%). While kenaf and ramie mainly showed hemicelluloses removal with steam explosion, jute exhibited an effective co-extraction of hemicelluloses and lignin, which greatly reduced its cellulose DP, hemicellulosic Xyl/Ara, and G-monomer. These findings explain why jute had the highest hexoses yield among the three crops and also suggest that G-monomer and Xyl may interact in a way that mainly determines wall polymers co-extraction with steam explosion.

  • Researchpp 2138-2151Zhang, Y., Chen, K., Wan, J., Zhuo, H., Li, J., Yang, R., Yang, W., Yang, F., and Wang, B. (2016). "Thermal dynamics and a comparison of the thermal stability of various non-wood pulps," BioRes. 11(1), 2138-2151.AbstractArticlePDF

    Specialty paper products made using natural pulps is an attractive field for the paper industry and for researchers. Studying the thermal dynamics of plant pulps is an important step toward improving the thermal stability of papers. This study has the aim of gaining detailed insight into the thermal properties of softwood, hardwood, flax, hemp, mulberry, bamboo, bagasse, and esparto pulps. Chemical composition and thermogravimetric analyses of these non-wood pulps were performed to find the correlations between the chemical, structural, and thermal properties of these pulps. In addition, the Malek model for kinetics of the thermo-decomposition process of pulps is proposed. The kinetics of the most probable mechanism function for G(α) = 1-(1-α) 1/2 of the thermo-decomposition process of plant fibers from 200 to 400 °C is deduced using the Malek model. This study also provides a method to help select the most promising pulps for specialty materials.

  • Researchpp 2152-2165Teng, J., Ma, H., Wang, F., Wang, L., and Li, X. (2016). "A facile and eco-effective catalytic system for synthesis of 5-hydroxymethylfurfural from glucose," BioRes. 11(1), 2152-2165.AbstractArticlePDF

    A facile and eco-friendly system for synthesis of 5-hydroxymethylfurfural (HMF) from glucose has been investigated with the catalyst dihydric phosphate (H2PO4—) in a methyl isobutyl ketone (MIBK)/H2O biphasic system. The results showed that the catalyst dosage, reaction temperature, and reaction time had noticeable effects on glucose conversion and the HMF yield; more than 50% yield of HMF was achieved at the optimum conditions. In addition, this catalytic system was broadly substrate-tolerant; a satisfactory HMF yield was obtained from higher substrate concentrations and complex substrates. Furthermore, this efficient catalyst was recycled up to nine consecutive times without the loss of catalytic activity.

  • Researchpp 2166-2173Li, L., Zhang, M., Song, S., and Wu, Y. (2016). "Starch/sodium stearate modified fly-ash based calcium silicate: Effect of different modification routes on paper properties," BioRes. 11(1), 2166-2173.AbstractArticlePDF

    Different modification routes using fly ash-based calcium silicate (FACS) with starch/sodium stearate were explored to mitigate the negative effect of filler on paper strength and allow for improved filler content. The morphology of the modified fillers and the properties of the filled paper were investigated. The modification route was found to be critical to the amount of starch/sodium stearate deposited on the surface of the filler particles. The most suitable modification route using FACS filler was as follows: starch (20% dosage on o.d. filler) was cooked, filler was added, and then sodium stearate was added (4% dosage on o.d. filler). The tensile index of the FACS-filled paper could be increased by 22% at 30% filler content under the best modification route. The brightness and bulk of the filled paper were also improved. However, the opacity of the filled paper was slightly decreased due to the deposition of starch/sodium stearate on the porous surface of the filler particles.

  • Researchpp 2174-2185Liao, R., Xu, J., and Umemura, K. (2016). "Low density sugarcane bagasse particleboard bonded with citric acid and sucrose: Effect of board density and additive content," BioRes. 11(1), 2174-2185.AbstractArticlePDF

    The development of natural adhesives derived from non-fossil resources is very important for the future. In this study, by taking sugarcane bagasse as the raw material, without using any synthetic resin but adding some eco-friendly additives (citric acid and sucrose), low density particleboards were successfully developed. The effects of board density and additive contents on the physical and mechanical properties of the boards were investigated. The bonding mechanism was observed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results showed that the low density bagasse particleboard had good mechanical properties and dimensional stability relative to its low board density. The modulus of rupture (MOR) and the thickness swelling (TS) values increased with increasing board density. The board with a density of higher than 0.40 g/cm³ and manufactured at 15% additive content can meet the requirements of the Chinese national forestry industry standard LY/T 1718-2007 (2007). Based on the results of the FTIR spectra, the additive not only increased the hydrogen bond but also the molecular linkage force (C-O-C). X-ray diffraction showed the relationship between crystallinity of cellulose and the strength of particleboard.

  • Researchpp 2186-2201Chin, S. X., Tasirin, S. M., Chan, C. H., Chia, C. H., Chook, S. W., Zakaria, S., and Sajab, M. S. (2016). "Catalytic conversion of empty fruit bunch (EFB) fibres into lactic acid by lead (II) ions," BioRes. 11(1), 2186-2201.AbstractArticlePDF

    Lactic acid (LA) is a potential platform chemical that can be produced from lignocellulosic biomass. The development of a cost-competitive, catalytic-based LA production system is gaining significant attention in modern biorefineries. A series of experimental study was carried out to investigate the chemocatalytic effect of the conversion of oil palm empty fruit bunch (EFB) fibers into lactic acid under hydrothermal conditions. Synthesis of chemicals from lignocellulosic biomass involves complex mechanisms because of the complex composition of the biomass. Therefore, experimental parameters, i.e., temperature, Pb(II) concentration, and reaction time were studied. It was found that production of LA is highly dependent on the experimental conditions. In this study, the highest LA yield obtained from EFB fibers was > 46% (230 °C, 2 mM Pb(II) after 4 h of reaction). However, a similar yield can be achieved either using higher Pb(II) and shorter reactions time or vice versa. The selective production of chemical compounds (glucose, 5-hydroxymethyl furfural (5-HMF), furfural, levulinic acid, and lactic acid) from EFB fibers is highly dependent on the availability of Pb(II) ions.

  • Researchpp 2202-2213Chang, C. Y., and Chang, F. C. (2016). "Development of electrospun lignin-based fibrous materials for filtration applications," BioRes. 11(1), 2202-2213.AbstractArticlePDF

    Lignin is a valuable biomaterial. It is both naturally abundant and readily available as a byproduct of the pulping processes, and the proper reprocessing of lignin is an effective way to achieve waste recovery. Lignin fiber mats with web structures can be produced using electrospinning techniques. Such fiber mats are a promising material for use in the production of filter products. This study focused on the development of filter media using electrospun lignin fiber mats. A series of tests were conducted (e.g., particle penetration and pressure drop) to evaluate the filtration efficiency of the proposed filters. The results indicated that the unfavorable mechanical properties of filters solely comprised of a single layer of the lignin fiber mat would have a negative impact on the filtration efficiency of such filters. However, lignin-based composite filters developed with polyethylene oxide (PEO) fiber mats and surgical mask filter layers exhibited a filtration efficiency comparable to filter products that filter out 95% of small particles (N95). Therefore, the proposed lignin-based composite filter has the potential for air filtration applications.

  • Researchpp 2214-2223Chen, T., Li, Y., Lei, L., Hong, M., Sun, Q., and Hou, Y. (2016). "The influence of stock consistency on the pollution load in washing process," BioRes. 11(1), 2214-2223.AbstractArticlePDF

    The influences of stock consistency on the kappa number, residual alkali of pulp, flow direction of lignin, chemical oxygen demand, oxidation with dichromate (CODCr), and five-day biochemical oxygen demand (BOD5) in effluents were investigated in a washing process. Compared with 15% stock consistency, 35% stock consistency could lead to a decrease of at least 25% in the consumption of washing water while cutting 75.27% and 46.29% of CODCr and BOD5 in washing effluents, respectively. Moreover, the residual lignin in effluents were reduced greatly from 39.35 g·t-1 to 12.76 g·t-1, which will be beneficial to treatment of washing and bleaching effluent. All the results showed that a higher stock consistency in the washing process could decrease the consumption of washing water, the generation of pollution, and the toxicity in bleaching effluent.

  • Researchpp 2224-2237Solikhin, A., Hadi, Y. S., Massijaya, M. Y., and Nikmatin, S. (2016). "Basic properties of oven-heat treated oil palm empty fruit bunch stalk fibers," BioRes. 11(1), 2224-2237.AbstractArticlePDF

    The fibers of oil palm empty fruit bunch (OPEFB) stalks were investigated to determine the changes in their basic properties after oven-heat treatment. The oven-heat treatment was conducted at 100 °C or 190 °C for 15 min. There were slightly noticeable morphological, chemical, and thermal alterations in oven-heat treated OPEFB stalk fibers for short duration. Scanning electron microscopy (SEM) revealed that the treated fibers had smooth surfaces and irregular heavy deposition of cementing agents. The highest cellulose content (41.68%) was present in OPEFB stalk fibers treated at 100 °C for 15 min, whereas the highest crystallinity index (48.74%) occurred in fibers treated at 190 °C for 15 min. The fibers comprised cellulose, lignin, and hemicellulose with a high percentage of C, O, K, and other elements. Based on differential scanning calorimetry (DSC) analysis, oven-heat treated and untreated OPEFB stalk fibers had similar thermal stability characteristics.

  • Researchpp 2238-2255Gavrilović-Grmuša, I., Dunky, M., Djiporović-Momčilović, M., Popović, M., and Popović, J. (2016). "Influence of pressure on the radial and tangential penetration of adhesive resin into poplar wood and on the shear strength of adhesive joints," BioRes. 11(1), 2238-2255.AbstractArticlePDF

    This work deals with the influence of specific pressure during the press process on the radial and tangential penetration of urea-formaldehyde (UF) adhesive into poplar, as well as on the shear strength of lap joints prepared at these different pressures. An epi-fluorescence microscope was used for measuring the adhesive penetration when investigating microtome slides (20-µm thick) cut from the joint samples. The average penetration depth (dap) and the size of the interphase region (I) increased with the increase of pressure from 0.5 to 1.0 N/mm2. Further increase in the pressure to 1.5 N/mm2 did not produce a significant change in dap or I. On the contrary, the area of filled lumens and rays (A) showed a steady decrease as the specific pressure increased. Such behavior influenced the filled interphase region (If), which also decreased with increased pressure. Tangential samples (radial penetration) obtained higher values of lap shear strength and showed less dependence on the specific pressure than the radial samples (tangential penetration). Higher shear strength based on radial penetration corresponded to the thicker interphase region of these samples. The highest shear strength for both directions of penetration was obtained for the specific pressure of 1.0 N/mm2.

  • Researchpp 2256-2268Li, J., Li, C., Wang, W., Zhang, W., and Li, J. (2016). "Reactivity of larch and valonia tannins in synthesis of tannin-formaldehyde resins," BioRes. 11(1), 2256-2268.AbstractArticlePDF

    Tannin-formaldehyde resins (TFR) were prepared by copolycondensation of tannins (larch tannin or valonia tannin) and formaldehyde. The performances of TFR and the free formaldehyde residue in the system during the course of reaction were tested. Chemical and structural changes of TFR during the reaction process were detected by Fourier transform infrared spectroscopy (FTIR) and 13C nuclear magnetic resonance spectroscopy (13C NMR). The results indicated that larch tannin-formaldehyde (LTF) resins demonstrated higher viscosity, higher solids content, shorter gel time, and lower free formaldehyde content than valonia tannin-formaldehyde (VTF) resins. The FTIR and 13C NMR tests demonstrated that larch tannin had higher reactivity than valonia tannin with formaldehyde, which was confirmed by the results of the free formaldehyde content measurement and the characteristics of TFR.

  • Researchpp 2269-2286Yee, Y. Y., Ching, Y. C., Rozali, S., Awanis Hashim, N., and Singh, R. (2016). "Preparation and characterization of poly(lactic acid)-based composite reinforced with oil palm empty fruit bunch fiber and nanosilica," BioRes. 11(1), 2269-2286.AbstractArticlePDF

    The properties of poly(lactic acid) (PLA) bio-composite films reinforced with oil palm empty fruit bunch (OPEFB) fiber and nanosilica were studied in this work. The composite films were prepared via the solvent casting method. The composites were characterized via Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy, field-emission scanning electron microscopy (FESEM), tensile testing, and X-ray diffraction (XRD). Ultraviolet visible spectroscopy results revealed that the PLA-based composites and neat PLA had similar light transmittances of approximately 89%. The FTIR and FESEM results showed that OPEFB fibers and nanosilica were embedded into the PLA matrix. The tensile strength of the composites with addition of nanosilica increased with an increasing fiber load content. The XRD analysis showed that the addition of organic or inorganic silica reduced the crystallinity of the composites. The water vapor permeability test results indicated that the inorganic silica decreased the diffusion rate of water molecules through the polymer film. The OPEFB-reinforced PLA blend with additional organic silica exhibited a higher thermal stability than the composites reinforced with inorganic silica.

  • Researchpp 2287-2296Alkasrawi, M., Al-Hamamre, Z., Al-Shannag, M., Abedin, M. J., and Singsaas, E. (2016). "Conversion of paper mill residuals to fermentable sugars," BioRes. 11(1), 2287-2296.AbstractArticlePDF

    The state of Wisconsin has existing pulp mill infrastructure capable of converting wood into biofuel and value-added products such as lumber, pulp, and paper. Each day, pulp and paper mills produce a waste material that is commonly referred to as sludge. Sludge is typically sent to a landfill or concentrated for burning to produce steam. The primary material present in pulp and paper mill sludge is fiber, which is mostly cellulose. This study showed how to convert pulp mill waste to fermentable sugars using commercially available enzymes. Preliminary economic analysis has shown that sludge can be converted into a fermentable sugar with chemicals costing less than $0.10 per pound of sugar produced.

  • Researchpp 2297-2307You, Y., Zhou, Z., Zhao, P., Bu, L., Jiang, J., and Zhang, W. (2016). "Comparison of pretreatment methods for production of ethanol from sugarcane bagasse," BioRes. 11(1), 2297-2307.AbstractArticlePDF

    Sugarcane bagasse (SCB) was modified by steam explosion pretreatment at 190 °C for 10 min and 210 °C for 5 min using green liquor (GL) combined with hydrogen peroxide (GL-H2O2) and ethanol (GL-Ethanol) for simultaneous saccharification and fermentation (SSF)-based ethanol production. The results showed that 85.02% and 100% of hemicelluloses were solubilized by steam explosion pretreatment at 190 °C for 10 min and 210 °C for 5 min, respectively. Moreover, 20.08% and 73.77% of the lignin was removed through GL-H2O2 and GL-Ethanol pretreatments, respectively. The steam explosion pretreatments greatly improved the specific surface area of the SCB and led to the highest ethanol yield of 92.20% at 190 °C for 10 min and 93.19% of 210 °C for 5 min, respectively. In addition, the ethanol yield reached 72.58% for the GL-Ethanol pretreatment, and about 70% of active lignin could be recovered from the pretreatment liquid. When the GL-H2O2 pretreatment was used, the maximum ethanol yield of 20.92% was achieved.

  • Researchpp 2308-2318Yang, W., Yang, F., Yang, R., and Wang, B. (2016). "Ammonium polyphosphate/melamine cyanurate synergetic flame retardant system for use in papermaking," BioRes. 11(1), 2308-2318.AbstractArticlePDF

    A new synergetic flame retardant system (SFRS) using ammonium polyphosphate/melamine cyanurate (APP/MCA) core-shell particle was synthesized and applied to papermaking. Cationic polyacrylamide (CPAM) was added to improve the adsorption of SFRS in pulp. Higher amounts of SFRS led to higher adsorption by pulp. Handsheets were produced with different amounts of SFRS. Thermal gravimetric analysis (TGA) and limiting oxygen index (LOI) were employed to test fire retardation in these handsheets. TGA and LOI results showed that this new core-shell SFRS is an effective flame retardant that improves the thermal stability of handsheets.

  • Researchpp 2319-2333He, S., Liu, T., and Di, M. (2016). "Preparation and properties of wood flour reinforced lignin-epoxy resin composite," BioRes. 11(1), 2319-2333.AbstractArticlePDF

    A lignin-epoxy resin composite was prepared by blending lignin/wood flour with an epoxy resin and polyamine. The effects of the wood flour on the mechanical, thermal creep, and creep recovery properties, as well as the microstructure of the composite, were studied. Among the mechanical properties, the initial modulus increased with increasing content of wood flour. The glass transition temperature (Tg) decreased, and the thermal stability first decreased and then increased, as the wood flour content increased. As the wood flour’s particle size was decreased, the initial modulus and other mechanical properties first increased and then decreased slightly. The Tg increased, and the thermal stability first decreased and then increased. The creep resistances of the composite were improved after the addition of the wood flour, and the 40 to 60 mesh wood flour exhibited better improvement than 60 to 120 mesh. The scanning electron microscopy (SEM) analysis revealed good interfacial bonding between the lignin, epoxy resin, and wood flour. Fiber breakage and fiber pullout were the main failure modes observed in this study.

  • Researchpp 2334-2348Taş, H. H., and Cetişli, B. (2016). "Estimation of physical and mechanical properties of composite board via adaptive neural networks, polynomial curve fitting, and the adaptive neuro-fuzzy inference system," BioRes. 11(1), 2334-2348.AbstractArticlePDF

    Several physical and mechanical properties of particle board were investigated using estimation modeling. Particleboards (0.65 g/cm3) were produced for five experimental groups, in which lavender plant waste, red pine chips, and urea formaldehyde (UF) resin were mixed in different proportions. After immersing the particleboards in water for 24 h, several properties including thickness swelling (TS), modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond strength (IBS) were determined. The statistical relevance of the experimental results was evaluated using multi-variance analysis (ANOVA), and the homogeneity between experimental groups was evaluated using Duncan tests. With the use of variable inputs and experimental results, estimation models using polynomial curve fitting(CF), adaptive neural networks (ANN), and an adaptive neuro-fuzzy inference system (ANFIS) were generated. The results obtained from the estimation models and experiments were then compared via root-mean-square error (RMSE) and R2 values. The ANFIS estimation model was the best alternative to the costly, long-term experimental methods, as it produced more economical and reliable results in a shorter period of time.

  • Researchpp 2349-2360Wang, Z., Sun, B., and Liu, J. (2016). "Effect of thermo-vacuum treatment on the color and chemistry of larch wood," BioRes. 11(1), 2349-2360.AbstractArticlePDF

    The objective of this study was to investigate the color and chemical changes of thermo-vacuum treated larch wood. Specimens were heat treated in a vacuum at various temperatures for 4 h. The color parameters of untreated and heat-treated samples were measured using the CIELab color system. Changes in the chemistry of larch wood were investigated using X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR) spectroscopy, and UV-Vis spectroscopy. The results showed that the color of larch wood became darker at higher treatment temperatures. The O/C ratio decreased with an increase in treatment temperature. The C1 peaks showed that there was an elevated content of lignin and extractives on the wood surface after heat treatment. There were more free radicals for thermally treated wood samples, as demonstrated by the increase in the intensities of the ESR signals. Some groups of lignin that contribute to the darkness of the wood increased after thermo-vacuum treatment. Changes in surface chemistry may be the cause of discolorations that occurred during thermo-vacuum treatment.

  • Researchpp 2361-2371Sun, Y., Ma, Y., Fang, G., Ren, S., and Fu, Y. (2016). "Controlled pesticide release from porous composite hydrogels based on lignin and polyacrylic acid," BioRes. 11(1), 2361-2371.AbstractArticlePDF

    For the controlled release of pesticides, a novel composite porous hydrogel (LBPAA) was prepared based on lignin and polyacrylic acid for use as the support frame of a pore structure for water delivery. The LBPAA was analyzed to determine its water-swelling and slow release properties. The controlled release properties of LBPAA were evaluated through experiments in relation to the cumulative release of pesticides, with particular emphasis on environmental effects and release models. The porous LBPAA hydrogel showed improved properties compared to polyacrylic acid, and could therefore be considered an efficient material for application in controlled release systems in agriculture.

  • Researchpp 2372-2380Ruan, T., Zeng, R., Yin, X. Y., Zhang, S. X., and Yang, Z. H. (2016). "Water hyacinth (Eichhornia crassipes) biomass as a biofuel feedstock by enzymatic hydrolysis," BioRes. 11(1), 2372-2380.AbstractArticlePDF

    Water hyacinth (Eichhornia crassipes) is an invasive floating plant that has caused many environmental problems in Asia. Efficiently removing and utilizing this biomass has become an urgent issue. In this work, the composition of water hyacinth biomass (WHB) was analyzed with the Van Soest method. The combined cellulose and hemicellulose content reached 58.6%, and the lignin content was very low compared with other biomass. An efficient alkali pretreatment technology for WHB was developed, and the enzymatic hydrolysis of WHB to reducing sugars was investigated. With favorable hydrolysis conditions for the alkali-pretreated WHB, the cellulose conversion rate reached almost 100%. Structural changes resulting from WHB pretreatment and hydrolysis were analyzed by Fourier-transform infrared spectrometry and scanning electron microscopy. This work demonstrates that WHB is an alternative cellulose source for bioenergy production.

  • Researchpp 2381-2392Yuan, Y., Yao, S., Nie, S., and Wang, S. (2016). "Conversion of glucose into HMF catalyzed by CPL-LiCl investigated using dual-wavelength UV spectrophotometry," BioRes. 11(1), 2381-2392.AbstractArticlePDF

    The process of dehydration of glucose to 5-hydroxymethylfurfural (HMF), using caprolactam-lithium chloride (CPL/LiCl) as a solvent, was investigated. Dual-wavelength ultraviolet spectrophotometry provides a new approach for the determination of glucose conversion rate and yield of HMF. Experiments were performed to demonstrate the accuracy and precision of this method. Various reaction parameters, such as the ratio of ionic liquid, reaction temperature, reaction time, catalyst dosage, and solid absorbent, were investigated in detail for the dehydration of glucose. The optimal conditions were explored. Finally, a possible mechanism for the dehydration of fructose to HMF was proposed.

  • Researchpp 2393-2402Zheng, R., Tshabalala, M. A., Li, Q., and Wang, H. (2016). "Photocatalytic degradation of wood coated with a combination of rutile TiO2 nanostructures and low-surface free-energy materials," BioRes. 11(1), 2393-2402.AbstractArticlePDF

    To test the hypothesis that wood coated with rutile TiO2 nanostructures can undergo degradation because of the photocatalytic activity of TiO2, three sets of wood specimens were aged at an accelerated rate. These three sets consisted of blank wood (BW), HDTMOS/MTMOS-coated wood (WHM), and TiO2/HDTMOS/MTMOS-coated wood (WTHM). After exposure to 155-h UV irradiation, the wettability of WTHM changed from hydrophobic to hydrophilic. This indicated that the initial low-surface free-energy materials underwent degradation because of the photocatalytic activity of TiO2. After exposure to 960 h of UV light irradiation and water spray, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA) of WTHM showed that rutile TiO2 nanostructures had partially peeled off the wood surface. This suggested that the adjacent wood surface also suffered degradation because of the photocatalytic activity of TiO2. Although the rutile TiO2 coating noticeably enhanced the color stability during UV light aging, it made a relatively small contribution to the color stability of the wood during UV light and water spray weathering process. This study suggests that to derive the greatest benefit from modification of wood surfaces with rutile TiO2 nanostructures for weathering resistance, it is necessary to take measures to inhibit the photocatalytic activity of TiO2 or to fix the TiO2 coating on the wood surface.

  • Researchpp 2403-2416Gao, J., Yang, X., Wan, J., He, Y., Chang, C., Ma, X., and Bai, J. (2016). "Delignification kinetics of corn stover with aqueous ammonia soaking pretreatment," BioRes. 11(1), 2403-2416.AbstractArticlePDF

    Soaking aqueous ammonia (SAA) pretreatment of corn stover was carried out at three temperatures (30, 50, and 70 ºC) and three concentrations of ammonia solution (5, 15, and 25 wt.%). The delignification kinetic model, based on three first-order reactions, was applied to describe the kinetic behavior of lignin removal from corn stover during SAA pretreatment. The first, second, and third terms were based on the initial, bulk, and residual phases of delignification, respectively. The results showed that the model fitted well with the data obtained from the experiments. The activation energies for the delignification reactions were estimated as 61.05 and 59.46 kJ/mol in the bulk and residual phases, respectively. Delignification selectivity increased with increasing reaction temperature.

  • Researchpp 2417-2437Joubert, A. J., Chimphango, A. F. A., and Görgens, J. F. (2016). "Effect of integrating xylan extraction from E. grandis into the kraft pulping process on pulp yield and chemical balance," BioRes. 11(1), 2417-2437.AbstractArticlePDF

    Kraft mills have the potential to pre-extract hemicellulose from wood as another value added product. The impacts of pre-extracting xylan on pulp and handsheet properties, sodium and sulfur balances, and chemical make-ups in the kraft pulping process of Eucalyptus grandis were assessed. Xylan extractions using white liquor, green liquor, and NaOH were done under varying extraction times, temperatures, and alkaline concentrations; residues were subsequently pulped at 170 °C for 45 min. The highest xylan yield (15.15% w/w) was obtained with 2 M NaOH, at 120 °C for 90 min followed by white liquor (13.27% w/w), utilizing 20% AA at 140 °C for 90 min. Green liquor extraction with 2% total titratable alkali (TTA), at 160 °C and an H-factor of 800 produced the lowest yield (7.83% w/w). However, the green liquor extractions were the most practical for integration into the kraft process due to their limited effect on pulp yield and properties of handsheets produced from the pre-extracted woodchips and the sulfur and sodium make-up increase. White liquor extractions would favour high pulp yield with low kappa number and reduced chemical charge and cooking time. These results are important for technical-economic assessment of integrated kraft pulp biorefineries.

  • Researchpp 2438-2456Yang, H., Huang, L., Liu, S., Sun, K., and Sun, Y. (2016). "Pyrolysis process and characteristics of products from sawdust briquettes," BioRes. 11(1), 2438-2456.AbstractArticlePDF

    The pyrolysis of briquettes made from biomass is an available and economic technological route for the production of briquette charcoal, but by-products (tar and gas) cannot be brought into full utilization, leading to the waste of resources and the addition of environmental concerns. Temperature is the most important parameter that affects the distributions and properties of briquette charcoal. This work investigated the three kinds of products of the pyrolysis of sawdust briquette in a fixed bed across a wide temperature range (250 to 950 °C). The purpose of this experiment was to study the pyrolysis process and the properties of the resulting products (briquette charcoal, liquid, and gas) of sawdust briquettes and explore the optimum operating temperature to generate good quality briquette charcoal, liquid, and gaseous products simultaneously. According to the results, the optimum pyrolysis temperature range was 450 to 650 °C, for which the briquette charcoal produced within this range had the highest calorific value (2,9.14 to 30.21 MJ/kg). Meanwhile, the liquid product is considered to be useful for liquid fuels or valuable chemical materials, and the low heating value of the gaseous product was 11.79 to 14.85 MJ/Nm3 in this temperature range.

  • Researchpp 2457-2469Guo, X., Zhu, C., and Guo, F. (2016). "Direct transformation of fructose and glucose to 5-hydroxymethylfurfural in ionic liquids under mild conditions," BioRes. 11(1), 2457-2469.AbstractArticlePDF

    Direct dehydration of fructose and glucose to 5-hydroxymethylfurfural (5-HMF) was studied using ionic liquids (ILs) without adding any catalysts. Various ILs were screened, and the highest 5-HMF yield of 95.6% was obtained using 1-butyl-3-methylimidazolium tosylate ([BMIM][TSO]) at 353 K for 30 min. Proton nuclear magnetic resonance (1H NMR) spectra confirmed that the sulfonate hydrolysates of anions of [BMIM][TSO] acted as active sites for the dehydration of fructose to 5-HMF. The [BMIM][TSO] catalyzed dehydration reaction showed relatively low activation energy (Ea). A mixture of dimethyl sulfoxide and 1-sulfobutyl-3-methylimidazolium trifluoromethane sulfate (DMSO-[BSO3HMIM][OTF]) was used at 413 K for 50 min for the dehydration of glucose, which yielded 59.8% 5-HMF. The addition of t-butanol, as an isomerization promoter, to DMSO-[BSO3HMIM][OTF] led to a higher 5-HMF selectivity without sacrificing 5-HMF yield.

  • Researchpp 2470-2482Akinpelu, E. A., Ntwampe, S. K. O., Mpongwana, N., Nchu, F., and Ojumu, T. V. (2016). "Biodegradation kinetics of free cyanide in Fusarium oxysporum-Beta vulgaris waste-metal (As, Cu, Fe, Pb, Zn) cultures under alkaline conditions," BioRes. 11(1), 2470-2482.AbstractArticlePDF

    The kinetics of free cyanide biodegradation were investigated under simulated winter (5 °C) and optimum conditions (22 °C and pH of 11) using a Fusarium oxysporum isolate grown on Beta vulgaris waste as a sole carbon source in the presence of heavy metals, i.e. As, Fe, Cu, Pb, and Zn. The highest free cyanide degradation efficiency was 77% and 51% at 22 °C and 5 °C respectively, in cultures containing free cyanide concentration of 100 mg F-CN/L. When compared with the simulated winter conditions (5 °C), the specific population growth rate increased 4-fold, 5-fold, and 6-fold in 100, 200 and 300 mg F-CN/L, respectively, for cultures incubated at 22 °C in comparison to cultures at 5 °C; an indication that the Fusarium oxysporum cyanide degrading isolate prefers a higher temperature for growth and cyanide biodegradation purposes. The estimated energy of activation for cellular respiration during cyanide degradation was 44.9, 54, and 63.5 kJ/mol for 100, 200, and 300 mg F-CN/L cultures, respectively, for the change in temperature from 5 to 22 °C.

  • Researchpp 2483-2491Yorur, H. (2016). "Utilization of waste polyethylene and its effects on physical and mechanical properties of oriented strand board," BioRes. 11(1), 2483-2491.AbstractArticlePDF

    The effect of adding waste polyethylene (WPE) was investigated at various ratios on some physical and mechanical properties of oriented strand board (OSB) panels. All of the test panels were bonded with 6% phenol-formaldehyde resin in three layers. The manufacturing parameters was 0/100, 10/90, 20/80, 30/70, 40/60, and 50/50 by weight% of WPE/wood strand. All the boards were manufactured to achieve targeted specific gravity of 0.65 g/cm3. Polyethylene improved the water resistance of the OSB panels because of its hydrophobicity. Based on the results of this study, thickness swelling, humidity, dimensional stability, water absorption, and screw withdrawal resistance of the samples were improved significantly. However, MOE, MOR, and internal bond strength values of the samples decreased with increasing WPE in the panels when compared to the control panels but met minimum requirements in EN 300 (type 1-2-3-4) control panels. The conclusion was reached that waste polyethylene can be used in the manufacture of OSB panels, resulting in the enhancement of above mentioned physical and mechanical properties, as well as a safe disposal and economical utilization.

  • Researchpp 2492-2503Tenhunen, T. M., Hakalahti, M., Kouko, J., Salminen, A., Härkäsalmi, T., Pere, J., Harlin, A., and Hänninen, T. (2016). "Method for forming pulp fibre yarns developed by a design-driven process," BioRes. 11(1), 2492-2503.AbstractArticlePDF

    A simple and inexpensive method for producing water-stable pulp fibre yarns using a deep eutectic mixture composed of choline chloride and urea (ChCl/urea) was developed in this work. Deep eutectic solvents (DESs) are eutectic mixtures consisting of two or more components that together have a lower melting point than the individual components. DESs have been previously studied with respect to cellulose dissolution, functionalisation, and pre-treatment. This new method uses a mixture of choline chloride and urea, which is used as a swelling and dispersing agent for the pulp fibres in the yarn-forming process. Although the pulp seemed to form a gel when dispersed in ChCl/urea, the ultrastructure of the pulp was not affected. To enable water stability, pulp fibres were crosslinked by esterification using polyacrylic acid. ChCl/urea could be easily recycled and reused by distillation. The novel process described in this study enables utilisation of pulp fibres in textile production without modification or dissolution and shortening of the textile value chain. An interdisciplinary approach was used, where potential applications were explored simultaneously with material development from process development to the early phase prototyping.

  • Researchpp 2504-2515Faletar, J., Jelačić, D., Sedliačiková, M., Jazbec, A., and Hajdúchová, I. (2016). "Motivating employees in a wood processing company before and after restructuring," BioRes. 11(1), 2504-2515.AbstractArticlePDF

    This research analyzed the motivating and demotivating factors amongst employees in a wood processing and furniture manufacturing company. Research was conducted over the year 2010, during the time of a full economic crisis and before the restructuring of the company was done. Analysis also was conducted in 2014, during the beginning of the economic recovery and after the restructuring of the company. Research was conducted with a survey using a questionnaire containing six questions with multiple choice statements. The questions were closed-ended, and respondents used the Likert four-level scale of importance for each statement. A total of 180 employees were surveyed, and results were statistically processed by using the χ2- test and cluster analysis. This study established that the motivation factors most important to employees in a company are significantly different during the time of an economic crisis, and in the period of economic recovery, i.e. before and after restructuring of the company. Employees were most concerned about physiological needs in the time of a crisis, whereas in the time of an economic recovery, employees consider social needs to be of more importance. Also, employees consider psychological circumstances of work to be more important in the year 2014 than in the year 2010. Employees’ overall motivation can be linked to higher efficiency and higher quality production and business results, and such research should be conducted more often.

  • Researchpp 2516-2525Gan, W., Yang, H., Zhang, Y., Shi, S. Q., Lin, C., Pan, L., and Huang, Z. (2016). "Synthesis and characterization of sucrose-melamine-formaldehyde adhesives," BioRes. 11(1), 2516-2525.AbstractArticlePDF

    The objective of this project was to use sucrose as a partial substitute for melamine in the synthesis of sucrose–melamine-formaldehyde (SMF) resin. The SMF was synthesized in a base condition. The wet bonding strength, shelf life, and formaldehyde emission of the SMF resin were determined. Fourier transform infrared spectroscopy (FT-IR) and mass spectroscopy (MS) were employed to analyze the chemical structure of the SMF resin. The shelf life of SMF resin increased as the sucrose content increased. Also as the sucrose content increased, the wet bonding strength decreased and the formaldehyde emissions decreased. The FT-IR and MS spectra revealed the structures of sucrose, melamine, and formaldehyde in the SMF, and chemical reactions of SMF resins occurred between the three primary hydroxyl groups of sucrose and methylolmelamine. Based on the results of this study, a sucrose to melamine mole ratio of 0.4:1 was determined to be the optimal ratio for the SMF resin.

  • Researchpp 2526-2535Heinemann, S., Saharinen, E., Särkilahti, A., and Salminen, L. I. (2016). "The effect of wood alignment on wood grinding - Part 2: Fines character and microscopic observations," BioRes. 11(1), 2526-2535.AbstractArticlePDF

    During industrial wood grinding, logs are pressed against a rotating stone, with the logs and fibre axes parallel to the axis of the stone. For this study, wood blocks were fed into a laboratory grinder with various alignments in relation to the surface of the grinding stone. The effects of the alignment on the properties of the pulp, the amount, and the quality of the fines were measured, and a grinding mechanism is proposed. In this paper, the obtained results showed that the pulp quality was highly sensitive to the angle between the stone surface and the log, and different for fatigue-based and force-based grinding. The tests were observed using microscopic techniques and discussed in terms of fines amount and fines quality. In gentle refining, the fibre structure is loosened by fatigue before it is bent on the surface, pressure pulses produce fibrillar material, and fibres develop good bonding ability. In forced grinding, the process is “violent” and the fibre wears and is crushed immediately on the surface into small particles with low bonding ability.

  • Researchpp 2536-2547Wang, Q., Wei, W., Chang, F., Sun, J., Xie, S., and Zhu, Q. (2016). "Controlling the size and film strength of individualized cellulose nanofibrils prepared by combined enzymatic pretreatment and high pressure microfluidization," BioRes. 11(1), 2536-2547.AbstractArticlePDF

    The production of functionalized polymers from biomass is of great interest. Cellulose nanofibrils (CNFs) isolated from lignocellulose have great potential in novel functional materials. In the present study, mild enzymatic treatment followed by high pressure microfluidization of a bleached softwood kraft pulp led to the release of individualized CNFs. Disk milling and high pressure microfluidization resulted in entangled networks of CNFs. CNFs from mild enzyme pretreatments were 8 to 12 nm in diameter and 200 to 400 nm in length, while CNFs from pure mechanical pretreatment were an entangled network of nanofibrils with a diameter of 10 to 20 nm. Films prepared from the resulting CNFs were flexible and semitransparent, and they exhibited high specific tensile stress and modulus. The specific tensile stress and modulus were increased by 3- to 5-fold and 5- to 11-fold, respectively. The specific tensile modulus of the CNFs films from mild enzyme treatments followed by microfluidization was approximately 15 to 16 MN·m/kg, while that of CNFs from pure mechanical fibrillation with or without microfluidization was 10 MN·m/kg and 14 MN·m/kg, respectively. The specific tensile strength of the CNFs films from mild enzyme treatment was slightly lower (72 to 98 kN·m/kg) than that of the CNFs films from pure mechanical fibrillation.

  • Researchpp 2548-2556Liu, Y., Xu, J., Zhang, Y., He, M., Liang, C., Yuan, Z., and Xie, J. (2016). "Improved ethanol production based on high solids fed-batch simultaneous saccharification and fermentation with alkali-pretreated sugarcane bagasse," BioRes. 11(1), 2548-2556.AbstractArticlePDF

    Alkali-pretreated sugarcane bagasse fiber was subjected to fed-batch simultaneous saccharification and fermentation (SSF) with a pre-hydrolysis process to increase the solids loading and produce a high concentration of ethanol. The hydrolysis medium and yeast feeding modes were investigated to determine suitable conditions for high sugar yield and ethanol production. Batch addition resulted in a cumulative substrate concentration of up to 36% (w/v) and enhanced ethanol concentrations, while ethanol conversion efficiency gradually declined. Enzymatic pre-hydrolysis and fermentation with fed-batch mode contributed to the SSF process. The highest ethanol concentration was 66.915 g/L with the conversion efficiency of 72.89%, which was achieved at 30% (w/v) solids content after 96 h of fermentation. Hydrolyzed medium and yeast were added in batch mode at 24 h of enzymatic hydrolysis and fermentation, respectively. Thus, combining the fed-batch mode with pre-hydrolysis SSF produced a high yield of ethanol.

  • Researchpp 2557-2567Yang, Z., Zhang, M., Li, K., and Chen, L. (2016). "Rapid detection of knot defects on wood surface by near infrared spectroscopy coupled with partial least squares discriminant analysis," BioRes. 11(1), 2557-2567.AbstractArticlePDF

    Natural defects, especially knots, on the surface of veneers have a great influence on the sorting and degradation of veneers. To realize rapid and accurate knot detection, a study on the possibility of detecting knots was carried out. Samples of poplar, eucalypt, and masson pine were used. The experiments mainly focused on the ability of using the models built with samples from one type of knot and normal wood to predict samples from a different type of knot and normal wood within the same wood species; and when only the samples from middle-sized knots and normal wood were used, whether or not the model based on one species could predict the samples from another species. The results showed that using the model built with small knots and normal wood to predict the larger knots and normal wood was not satisfactory, but the model based on large knots and normal wood can predict the samples from smaller knots and normal wood under a certain condition. When only the middle-sized knots and normal wood from the three species were used, the model built with eucalypt samples could predict the samples from poplar, and vice versa; however, the model built with masson pine samples could not predict the other two sample species, and vice versa.

  • Researchpp 2568-2582Li, Y., Huang, H., Wu, G., Yan, S., Chang, Z., Bi, J., and Chen, L. (2016). "The effects of UV-A on dry rice straw decomposition under controlled laboratory conditions," BioRes. 11(1), 2568-2582.AbstractArticlePDF

    In arid and semi-arid areas, organic matter decomposition is stimulated by ultraviolet radiation. In this paper, the association between straw decomposition and UV-A exposure was evaluated. Oven-dried rice straw samples were chronically exposed to UV-A radiation and examined periodically for up to 90 days at room temperature. Scanning electron microscopy (SEM) showed that noticeable disintegration of the fiber structure occurred on the irradiated sample surface in comparison to the control. At the end of the UV-A treatment period, straw mass had decreased by 5%, and dissolved organic carbon (DOC) increased by 18%. The content of cellulose, hemicellulose, and lignin of the irradiated straw decreased by 29.3%, 14.4% and 49.3%, respectively. The marked loss of nitrogen and potassium in the exposed straw were also observed. Thermogravimetric analysis (TGA) showed that treatment with UV-A radiation tended to decrease the mass loss rate and the thermal degradation temperature of the straw biomass from 220 °C to 208 °C. Infrared spectrometric analysis (ATR-FTIR) showed that functional groups, e.g., C–OH and C–O–C, were disrupted obviously due to UV-A exposure. These results suggest that ultraviolet-A irradiation facilitates straw decomposition by direct photochemical degradation.

  • Researchpp 2583-2596Wei, W., Chen, T., Niu, M., Xie, Y., and Wang, X. (2016). "Optimized pretreatment of kenaf (Hibiscus cannabinus) phloem insulation cotton," BioRes. 11(1), 2583-2596.AbstractArticlePDF

    Using response surface methodology, the pretreatment conditions of kenaf fibers were optimized to improve the tensile strength of kenaf phloem insulation cotton (KPIC). The effects and interactions of three parameters—sodium hydroxide concentration (X1), soaking time (X2), and beating time (X3) —on the tensile strength of the kenaf fibers were investigated. The Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and thermal conductivity of the KPICs further confirmed the validity of the optimal pretreatment conditions. Sodium hydroxide concentration had the greatest effect on kenaf fibers. The maximum tensile strength of 117.6 N resulted from a sodium hydroxide concentration of 4%, soaking time of 50 h, and beating time of 12 min. As shown by FTIR and XRD, optimized pretreatment generated surface functional groups and increased the tensile strength of fibers. It has a low thermal conductivity of 0.032 W/mK. In conclusion, the pretreatment of kenaf fiber significantly improves the tensile strength of KPIC and also improves the retention rate of the chemicals used during the preparation of KPIC. As an environment friendly and renewable material, the KPIC has a great application prospect with its good thermal conductivity.

  • Researchpp 2597-2606Ma, Y., Wu, P., Zhang, Y., Xuan, C., and Su, H. (2016). "Effect of vibration during compression on the process of making biomass briquettes," BioRes. 11(1), 2597-2606.AbstractArticlePDF

    An attempt to introduce assistive vibration into the process of biomass briquetting was carried out, with a focus on lowering the energy requirement and improving product quality. The effects of assistive vibration on the surface morphology of briquettes using corn stalk and wheat straw as the experimental materials was investigated, and it was found that assistive vibration can increase the flow capacity of the material and improve the press transmission as well as the uniformity of internal stresses to facilitate the inner-layer-material compression and lower the springback of the compressed material. The biomass particles were still bonded primarily by mechanical interlocking and solid bridges, but the distribution range and size of the voids or gaps between adjacent particles were reduced, and the particles or fibers of thicker layer appeared to be “lying down” instead of “standing,” indicating a higher density of the product compared with the case of compaction without vibration assistance.

  • Researchpp 2607-2616Wang, S., Zhang, T., Li, J., Fang, L., Liu, X., and Guo, M. (2016). "Exploration of the origin of the UV absorption performance of windmill palm fiber," BioRes. 11(1), 2607-2616.AbstractArticlePDF

    This study aims to investigate the ultraviolet (UV) absorption property of palm fiber and to reveal the mechanism underlying its UV-shielding behavior. The UV spectra of various solvent extracts of palm fiber were investigated. Fourier transform infrared spectroscopy (FTIR) and UV spectra were used to analyze the treated palm fiber, 100% α-cellulose, and raw palm fiber. The UV absorbances of palm, bamboo, and ramie fibers and their lignin extracts were comparatively investigated. The results showed that lignin is the main contributor to the UV absorption property of palm fiber. UV spectroscopy of the solvent extracts showed that a dioxane solution exhibited an excellent extraction capacity. The analysis of the FTIR and UV spectra of treated palm fiber, 100% α-cellulose, and raw palm fiber confirmed that there was a strong correlation between the UV absorption property and the chemical components. The results showed that the palm fiber exhibited superior UV absorption properties and that the lignin content noticeably affected the UV absorption degree.

  • Researchpp 2617-2628Xu, K., Zheng, Z., Huang, S., Chen, T., and Tang, Z. (2016). "Influence of glycidyl methacrylate grafting on the mechanical, water absorption, and thermal properties of recycled high-density polyethylene/rubber seed shell particle composites," BioRes. 11(1), 2617-2628.AbstractArticlePDF

    Rubber seed shell (RSS) was modified by grafting treatment using glycidyl methacrylate (GMA) at various concentrations. The RSS was then used to reinforce high-density polyethylene (HDPE). The effects of modification on the mechanical, water absorption, and thermal properties of the RSS/HDPE composites were studied using a mechanical testing instrument, weighing method, Vicat softening temperature (VST) testing, thermogravimetry, and dynamic mechanical analysis. The results showed that the GMA grafting produced an improvement in the flexural and tensile properties of the composites. The water absorption rate of the composites also had an obvious decrease. While a slight increase in VST was found, the various concentrations of GMA showed no improvement in VST. GMA modification also could elevate the thermal stability of the composites at the initial decomposition stage. The optimum grafting concentration of GMA (2.5%) led to the lowest thermal weight loss (37.07% and 26.56%) during the first and second decomposition stages. The E’ values of the composites had a significant increase with the addition of GMA. There were two peaks of tan δ for the untreated samples, but the modified samples exhibited a shift in the transition peak at higher temperatures; moreover, the second peak disappeared.

  • Researchpp 2629-2639Li, Z., Li, J., Xu, J., Mo, L., Feng, Y., and Chen, K. (2016). "The fluidization properties of bagasse pulp suspensions in a rotary device," BioRes. 11(1), 2629-2639.AbstractArticlePDF

    Suspensions of bleached bagasse pulp at 0% to 15% mass concentrations were sheared in a concentric cylinder rotary device to study the pulp suspension’s fluidization properties. The use of a baffled chamber, with blade rotors, imposed shear stress within the suspensions and prevented slip at the chamber walls. Linear-type, hollow-type, and screw-type rotors were used to explore the influence of rotor structure on fluidization properties. The torque was measured as a function of rotational speed. The torque vs. rotational speed curves and flow phenomenon were found to depend on the mass consistency of the pulp suspensions and the gap between the rotor and chamber. The structure of the rotor had little influence on the fluidization of the pulp suspensions, and the critical rotational speed that makes the pulp suspensions turbulent was similar for all rotor types. The gap between the rotor and chamber should be small to let pulp suspensions fluidize at low rotational speed.

  • Researchpp 2640-2654Hauptmann, M., and Majschak, J. P. (2016). "Characterization of influences on the wall stability of deep drawn paperboard shapes," BioRes. 11(1), 2640-2654.AbstractArticlePDF

    Deep drawn shapes with orthogonal wall components are usually evaluated by shape accuracy and visual quality. There have been only a few investigations on the stability of such structures; however, the effect of the wrinkles on the stability of the wall is important for packaging applications and can support the shape accuracy. This paper focuses on the influences of process parameters on the stability of orthogonal walls of shapes produced by deep drawing with rigid tools and immediate compression. The wall stability was evaluated by tensile testing orthogonal to the direction of the wrinkles. The stability distribution was characterized with regard to the drawing height, and a comparison was made between the two different materials. The wall stability decreased with increases in the forming height. Furthermore, a blank holder force design and z-directional compression level improved the wall stability. Together with an elevated moisture content of the material and thermal energy supply that delivered two to three times higher resistance against wrinkle extension, these effects drastically improved the wall stability.

  • Researchpp 2555-2664Xu, Y., Zhang, W., Sun, H., Yue, X., and Zhang, D. (2016). "Study on the dynamic viscoelasticity of bamboo kraft black liquor," BioRes. 11(1), 2555-2664.AbstractArticlePDF

    The dynamic viscoelasticity of bamboo kraft pulping black liquor under various temperatures (ranging from 50 to 80 °C) and solids concentrations (60 to 80 wt.%) was studied. Rotational rheometer analysis data indicated that the viscoelastic motion law with a high solids concentration in black liquor was in accordance with the Kelvin model, and black liquor with a medium concentration conformed to the Maxwell model. As a result, the temperature and solids concentration greatly influenced the dynamic viscoelasticity of bamboo kraft pulping black liquor. For instance, the modulus increased as the solids concentration increased, indicating that the viscous component of black liquor was prominent. For this reason, it was easier to soften the bamboo black liquor, providing a favorable condition for the pure viscosity of black liquor. Steady shear thinning was apparent during the frequency shear process. The dynamic viscosity, storage viscosity, and complex viscosity of the black liquor decreased as the shear frequency increased. The quantitative relationship between dynamic viscosity and angular frequency can be described using the Power Law model.

  • Researchpp 2665-2683Sharba, M. J., Leman, Z., Sultan, M. T. H., Ishak, M. R., and Hanim, M. A. A. (2016). "Partial replacement of glass fiber by woven kenaf in hybrid composites and its effect on monotonic and fatigue properties," BioRes. 11(1), 2665-2683.AbstractArticlePDF

    Natural–synthetic fiber hybrid composites offer a combination of high mechanical properties from the synthetic fibers and the advantages of renewable fibers to produce a material with highly specific and determined properties. In this study, plain-woven kenaf/glass reinforced unsaturated polyester (UP) hybrid composites were fabricated using the hand lay-up method with a cold hydraulic press in a sandwich-configuration laminate. The glass was used as a shell with kenaf as a core, with an approximate total fiber content of 40%. Three glass/kenaf weight ratios percentages of (70/30)% (H1), (55/45)% (H2), and (30/70)% (H3) were used to fabricate hybrid composites. Also pure glass/UP and kenaf/UP were fabricated for comparison purposes. Monotonic tests, namely tensile, compression, and flexural strengths of the composites, were performed. The morphological properties of tensile and compression failure of kenaf and hybrid composites were studied. In addition, uniaxial tensile fatigue life of hybrid composites were conducted and evaluated. The results revealed that the hybrid composite (H1) offered a good balance and the best static properties, but in tensile fatigue loading (H3) displayed low fatigue sensitivity when compared with the other hybrid composites.

  • Researchpp 2684-2697Zhu, S., Guo, Y., Chen, Y., Su, N., Zhang, K., and Liu, S. (2016). "Effects of the incorporation of nano-bamboo charcoal on the mechanical properties and thermal behavior of bamboo-plastic composites," BioRes. 11(1), 2684-2697.AbstractArticlePDF

    To illustrate the effects of nano-bamboo charcoal (NBC) on the properties of bamboo plastic composites (BPC), nano-bamboo charcoal-bamboo plastic composites (NBC-BPC) were prepared at 0%, 2.5%, 5%, 7.5%, 10%, and 12.5% (w/v) NBC and characterized. The effects of NBC on the water absorption, fractured surfaces, mechanical properties, and thermal properties of the composites were investigated. NBC had strong interfacial interaction in the BPC, which greatly improved the interfacial adhesion of bamboo flour (BF) and high-density polyethylene (HDPE). The water resistance, flexural strengths, and tensile strengths of the composites were enhanced compared with traditional BPC when the volume of NBC reached a specific loading. These results demonstrated that the incorporation of NBC slightly improved the thermal properties of the synthesized composites.

  • Researchpp 2698-2711Zhang, L., Guo, Y., Zhou, J., Sun, G., Han, Y., and Wang, X. (2016). "Synthesis and characterization of cellulose-graft-poly (p-dioxanone) copolymers via homogeneous ring-opening graft polymerization in ionic liquids," BioRes. 11(1), 2698-2711.AbstractArticlePDF

    Cellulose-graft-poly(p-dioxanone) copolymers (cellulose-g-PPDO) were homogeneously prepared via ring-opening graft polymerization (ROP) between p-dioxanone (PDO) and hydroxyl groups of cellulose using the catalyst 4-dimethylaminoptridine (DMAP) in the ionic liquid 1-butyl-3-methylimidazolium chloride (BmimCl). Chemical structures and physical properties of the cellulose-g-PPDO copolymers were characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H, 13C, 1H-13C 2D heteronuclear single quantum correlation (HSQC)-NMR)), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) techniques. By adjusting the reaction conditions, including the molar ratio of PDO to the anhydroglucose unit (AGU), amount of DMAP, and reaction temperature and time, the structure of the graft copolymers could be altered, and a series of copolymers with molar substitutions (MSs) in the range of 1.09 to 6.97 and polymerization degrees (DPs) varying from 1.85 to 2.88 were obtained. The graft copolymers exhibited a noticeably lower thermal stability than cellulose. After the attachment of PPDO groups, the crystalline structure of cellulose was disrupted because of the elimination of the inter- and intra-molecular hydrogen bonds of cellulose chains.

  • Researchpp 2712-2722Gao, W., Lee, S. U., Li, J., and Lee, J. W. (2016). "Development of improved process with treatment of cellulase for isolation of ampelopsin from dried fruits of Ampelopsis grossedentata," BioRes. 11(1), 2712-2722.AbstractArticlePDF

    The commercial method for isolation of ampelopsin, one of the most common flavonoids isolated from the plant species Ampelopsis grossedentata, is a simple hydrothermal extraction at high temperature. To develop an improved process to isolate ampelopsin, the effects of treatment of cellulase on hydrolysis of the dried fruit of A. grossedentata were investigated. The treatment of cellulase was found to decrease the temperature and time for hydrolysis of the dried fruit of A. grossedentata. The conditions of the filter press and continuous flow centrifuge for removal of insoluble materials from the hydrolysate of the dried fruit of A. grossedentata were optimized. The recovery yield of ampelopsin from the dried fruits of A. grossedentata was 39.4%, as determined by HPLC chromatographic analysis. A safe and economical process at low temperature with treatment of cellulase for the isolation of ampelopsin was developed in this study.

  • Researchpp 2723-2733Wang, H., Liu, Y., Wang, Z., Yang, G., and Lucia, L. A. (2016). "Structural analysis of fast-growing aspen alkaline peroxide mechanical pulp lignin: A post-enzymatic treatment," BioRes. 11(1), 2723-2733.AbstractArticlePDF

    An enzymatic mild acidic hydrolysis was used to separate and purify residual lignin from alkaline peroxide mechanical pulp (APMP). Using the optimum conditions for the laccase treatment (pH 4.5, temperature 50 °C, lignin consistency of 1%, a reaction time of 60 min, and a laccase dosage of 8 μ/g), oven-dried lignin was treated with laccase and in a laccase mediator system (LMS) to explore the mechanism for laccase and the LMS modification of APMP. The changes of functional groups in lignin were analyzed using nuclear magnetic resonance (31P-NMR and 13C-NMR). The molecular weight distributions of the lignin samples were confirmed by gel permeation chromatography (GPC). The 31P-NMR and 13C-NMR spectra revealed that the lignin structure changed significantly with the laccase and the LMS treatments. Meanwhile, GPC demonstrated that laccase without a mediator could lead to the polymerization of lignin, while the LMS could degrade the lignin. Hence, it was concluded that laccase is an attractive enzyme for lignin modification.

  • Researchpp 2734-2743Wu, Y., Sha, T., Zhao, Z., He, Z., and Yi, S. (2016). "Influence of different pretreatments on the acoustic properties of dawn redwood (Metasequoia glyptostroboides Hu et Cheng)," BioRes. 11(1), 2734-2743.AbstractArticlePDF

    To modify the acoustic properties of dawn redwood (Metasequoia glyptostroboides Hu et Cheng), thermal, ultrasonic, and combined thermal-ultrasound treatments were employed in this work. The changes in the logarithmic decrement (δ), specific Young’s modulus (E’/ρ), and extractives content were examined. The results showed that thermal and ultrasonic treatments were both essential for a decrease in the logarithmic decrement (δ) and an increase in the specific Young’s modulus (E’/ρ) of dawn redwood (Metasequoia glyptostroboides Hu et Cheng). A superposition effect on decreasing of the logarithmic decrement (δ) was discovered after thermal-ultrasound combined treatment. The amounts of extractives, extracted by 95 °C distilled water, 1% NaOH solution, and benzene-ethanol solution, decreased after thermal and ultrasonic treatments. Moreover, there was a linear correlation between logarithmic decrement (δ) and extractives, in which extractives from 1% NaOH solution and 95 °C distilled water had a significant effect. Finally, dawn redwood samples treated with ultrasonic power at 340 W for 9 min at a thermal temperature of 200 °C were chosen as the optimal method in this research.

  • Researchpp 2744-2755Liu, L., Huang, Y., and Liu, C. (2016). "Prediction of rice husk gasification on fluidized bed gasifier based on aspen plus," BioRes. 11(1), 2744-2755.AbstractArticlePDF

    A biomass gasification model was developed using Aspen Plus based on the Gibbs free energy minimization method. This model aims to predict and analyze the biomass gasification process using the blocks of the RGibbs reactor and the RYield reactor. The model was modified by the incomplete equilibrium of the RGibbs reactor to match the real processes that take place in a rice husk gasifier. The model was verified and validated, and the effects of gasification temperature, gasification pressure, and equivalence ratio (ER) on the gas component composition, gas yield, and gasification efficiency were studied on the basis of the Aspen Plus simulation. An increasing gasification temperature was shown to be conducive to the concentrations of H2 and CO, and gas yield and gasification efficiency reached peaks of 2.09 m3/kg and 83.56%, respectively, at 700 °C. Pressurized conditions were conducive to the formation of CH4 and rapidly increased the calorific value of syngas as the gasification pressure increased from 0.1 to 5 MPa. In addition, the optimal ER for gasification is approximately 0.3, when the concentrations of H2 and CO and the gasification efficiency reach peaks of 23.65%, 24.93% and 85.92%, respectively.

  • Researchpp 2756-2767Septiningrum, K., Ohi, H., Nakagawa-izumi, A., and Kosugi, A. (2016). "Characterization of hexenuronosyl xylan-degrading enzymes produced by Paenibacillus sp. 07," BioRes. 11(1), 2756-2767.AbstractArticlePDF

    The enzyme involved in hexenuronic acid (HexA) removal from kraft pulp was identified in Paenibacillus sp. strain 07. Extracellular and intracellular enzymes of Paenibacillus sp. were assessed for their hexenuronosyl-xylotriose (∆X3) degradation activity. First, ∆X3 was obtained from hardwood kraft pulp by enzymatic hydrolysis using three commercial enzymes. Crude extracellular and intracellular enzyme fractions were obtained from Paenibacillus cultures cultivated in 0.5% (w/v) birch wood xylan as the sole carbon source. The ∆X3-degrading activities of the enzyme fractions were measured by hydrolysis assays in sodium acetate buffer containing ∆X3 substrate (pH 6) at 50 °C. The reaction products were analyzed by high-performance anion-exchange chromatography with pulsed amperometric detection. The enzyme fractions displayed different chromatogram patterns. After treatment with the intracellular enzyme fraction, the chromatograms displayed xylose and hexenuronosyl xylobiose (∆X2) peaks. The chromatogram patterns of the extracellular fraction assays indicated xylose, xylotriose, and ∆X2 production. Thus, the intracellular enzymes of Paenibacillus can hydrolyze the xylosidic linkages at the reducing ends of ∆X3, whereas a specific extracellular enzyme can hydrolyze HexA. This enzyme is potentially applicable to HexA removal during bio-bleaching.

  • Researchpp 2768-2783Wu, X., An, Q., Dai, Y., and Si, J. (2016). "Investigating lignocellulose in cornstalk pretreated with Trametes pubescens Cui 7571 to improve enzymatic saccharification," BioRes. 11(1), 2768-2783.AbstractArticlePDF

    This study investigated the degradation and enzymatic saccharification of cornstalk by white-rot and brown rot fungi. The fungal strains Trametes pubescens Cui 7571, Trametes velutina Dai 10149, and Antrodia wangii Cui 7568 were analyzed in solid-state fermentation cultures. Various extracellular enzyme activities were assessed to determine biochemical changes during the degradation process. Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis were used to determine the structural changes. A correlation analysis between the chemical composition of cornstalk, extracellular enzyme activities, and structural changes indicated that T. pubescens Cui 7571 broke down lignin efficiently and subsequently degraded cellulose, and hemicellulose digestion was not affected by the lignin barrier. Enzymatic hydrolysis demonstrated that the T. pubescens Cui 7571-pretreated samples increased cellulose and hemicellulose conversion in cornstalk. Overall, T. pubescens Cui 7571 displayed excellent performance as a biological pretreatment agent, and lignin played a significant role in the enzymatic saccharification of cornstalk.

  • Researchpp 2784-2796Alghamdi, A. A., Abdel-Halim, E. S., and Al-Othman, Z. A. (2016). "Low-temperature bleaching of cotton cellulose using an ultrasound-assisted tetraacetylethylenediamine/ hydrogen peroxide/triethanolamine system," BioRes. 11(1), 2784-2796.AbstractArticlePDF

    This work investigated the efficiency of a tetraacetylethylenediamine/ hydrogen peroxide/triethanolamine (TAED/H2O2/TEA) system for low-temperature bleaching of cotton fabric, with and without ultrasonic assistance. The low-temperature bleaching results were compared to those obtained from a conventional H2O2 bleaching system. The application of TAED/H2O2/TEA without ultrasonic assistance to grey cotton fabric with a whiteness index (WI) of 28 and tenacity of 40 CN/Tex resulted in full bleaching of the cotton fabric at 70 °C within 60 min. This low-temperature bleaching system produced a bleached cotton fabric with a WI of 69 and tenacity of 38 CN/Tex, while the conventional H2O2 bleaching system gave a bleached cotton fabric WI of 73 and tenacity of 32 CN/Tex. The application of ultrasound to a low-temperature bleaching system showed a reduction in the duration required for full bleaching to 30 min rather than 60 min and gave bleached fabrics of the same physiochemical properties.

  • Researchpp 2797-2808Xu, Y., Zuo, L., Qian, X., and Wang, J. (2016). "Preparation and characterization of cellulose-silver nanocomposites by in situ reduction with alkalis as activation reagent," BioRes. 11(1), 2797-2808.AbstractArticlePDF

    A simple, environmentally friendly, and efficient synthesis method for cellulose/silver (Ag) nanocomposites was developed by microwave heating an alkaline aqueous solution of cellulose fiber and silver nitrate (AgNO3), which resulted in good utilization of silver ions and a product with high silver content. The effect of the alkaline compounds and reducing agents on the silver content and utilization rate of silver ions was investigated using atom absorption spectroscopy (AAS). The morphology, size, thermal stability, and surface components of cellulose/Ag nanocomposites were investigated using scanning electron microscopy (SEM), thermogravimetric analysis (TG), differential scanning calorimetry (DSC), and Raman spectroscopy. The alkaline compound and reducing agent influenced the size and shape of the silver nanoparticles. Reduced silver ions had the greatest influence on the surface components of cellulose; however, nano-silver particles exhibited no obvious influence on cellulose’s thermal stability. Furthermore, cellulose/Ag nanocomposites exhibited excellent antibacterial activity against Escherichia coli and Staphylococcus aureus.

  • Researchpp 2809-2819Dönmez, İ. E., Hemming, J., and Willför, S. (2016). "Bark extractives and suberin monomers from Arbutus andrachne and Platanus orientalis," BioRes. 11(1), 2809-2819.AbstractArticlePDF

    Arbutus andrachne and Platanus orientalis grow naturally in Turkey. They do not occur in stands but can be seen as solitary trees. A. andrachne is seen in coastal parts of Anatolia, whereas P. orientalis can be found from west to the east of Turkey, mostly in river banks. Lipophilic extractives, hydrophilic extractives, and suberin monomers from Arbutus andrachne and Platanus orientalis bark was analyzed by chromatography. The total amount of lipophilic extractives was higher in P. orientalis (8.55 mg/g). However, the total amount of hydrophilic extractives had a bigger proportion, 100.86 mg/g, in A. andrachne bark. Dioic and hydroxy acids were the dominant group in the suberin monomers of both species of bark. Acid 1,18-dioic-18:0 and acid 18-hydroxy-18:1 were determined as the main compounds of suberin monomers in both samples. In addition, total amount of suberin monomers was determined to be 11.36 mg/g in A. andrachne and 15.95 mg/g in P. orientalis bark.

  • Researchpp 2820-2838Cardona, F., Sultan, M. T., Abu Talib, A. R., Ezzah, F., and Derahman, A. (2016). "Interpenetrating polymer network (IPN) with epoxidized and acrylated bioresins and their composites with glass and jute fibres," BioRes. 11(1), 2820-2838.AbstractArticlePDF

    Epoxidized (EHO) and acrylated (AEHO) bio-resins from hemp oil were synthesized, and their interpenetrating networks (IPNs) were investigated in reinforced bio-composites with natural jute fibres and glass fibres. The mechanical properties (tensile, flexural, Charpy impact, and inter-laminar shear) and viscoelastic properties (glass transition temperature, storage modulus, and crosslink density) of the bio-resins and their hybrid IPNs EHO/AEHO system were investigated as a function of the level of bio-resin hybridization. The hybrid bio-resins exhibited interpenetrating network (IPN) behaviour. Composites prepared with the synthetic vinyl ester (VE) and epoxy resins showed superior mechanical and viscoelastic properties compared with their bio-resins and IPNs-based counterparts. With glass fibre (GF) reinforcement, increases in the EHO content of the IPNs resulted in increased stiffness of the composites, while the strength, inter-laminar shear strength (ILSS), and impact resistance decreased. However, in the jute fibre reinforced bio-composites, increases in AEHO content generated increased tensile modulus, ILSS, and mechanical strength of the bio-materials. Crosslink density and glass transition temperature (Tg) were also higher for the synthetic resins than for the bio-resins. Increased AEHO content of the IPNs resulted in improved viscoelastic properties.

  • Researchpp 2839-2849Nur Firdaus, M. Y., Osman, H., Metselaar, H. S. C., and Rozyanty, A. R. (2016). "Preparation and characterization of active SiO2 from Cymbopogon citratus ash calcined at different temperature," BioRes. 11(1), 2839-2849.AbstractArticlePDF

    Cymbopogon citratus orlemon grass, is a potential renewable herbaceous biomass alternative. Lemon grass contains silica, which is available for extraction as a filler for various applications. Lemon grassash is produced at calcination temperatures of 0, 400, 525, 600, and 700 ˚C. The silica content of the lemon grass ash was characterized by X-ray fluorescence (XRF), X-ray powder diffraction (XRD), scanning electron microcopy (SEM), and Fourier transform infrared (FTIR) analysis. The shape and texture of the lemon grass ash were studied by SEM. The highest silica content recorded was 24.00% for lemon grass calcined at 400 °C. The porosity of the lemon grass ash increased as the calcination temperature increased from 0 °C to 700 °C. XRD analysis showed that the crystallinity of silica in the lemon grass ash increased with increasing calcination temperature. FTIR analysis confirmed the presence of organic structure in lemon grass without calcination and the inorganic structure of siloxane and silanol bonds present in lemon grass calcined at different temperatures.

  • Reviewpp 2850-2885Tang, Y., Rosenberg, J. N., Bohutskyi, P., Yu, G., Betenbaugh, M. J., and Wang, F. (2016). "Microalgae as a feedstock for biofuel precursors and value-added products: Green fuels and golden opportunities," BioRes. 11(1), 2850-2885.AbstractArticlePDF

    The prospects of biofuel production from microalgal carbohydrates and lipids coupled with greenhouse gas mitigation due to photosynthetic assimilation of CO2 have ushered in a renewed interest in algal feedstock. Furthermore, microalgae (including cyanobacteria) have become established as commercial sources of value-added biochemicals such as polyunsaturated fatty acids and carotenoid pigments used as antioxidants in nutritional supplements and cosmetics. This article presents a comprehensive synopsis of the metabolic basis for accumulating lipids as well as applicable methods of lipid and cellulose bioconversion and final applications of these natural or refined products from microalgal biomass. For lipids, one-step in situ transesterification offers a new and more accurate approach to quantify oil content. As a complement to microalgal oil fractions, the utilization of cellulosic biomass from microalgae to produce bioethanol by fermentation, biogas by anaerobic digestion, and bio-oil by hydrothermal liquefaction are discussed. Collectively, a compendium of information spanning green renewable fuels and value-added nutritional compounds is provided.

  • Reviewpp 2886-2963Hubbe, M. A., and Gill, R. A. (2016). "Fillers for papermaking: A review of their properties, usage practices, and their mechanistic role," BioRes. 11(1), 2886-2963.AbstractArticlePDF

    Issues of cost and product quality have caused papermakers to place increased attention on the use of mineral additives, which are the subject of this review article. Technologists responsible for the production of paper can choose from a broad range of natural and synthetic mineral products, each of which has different characteristic shapes, size distributions, and surface chemical behavior. This article considers methods of characterization, and then discusses the distinguishing features of widely available filler products. The mechanisms by which fillers affect different paper properties is reviewed, as well as procedures for handling fillers in the paper mill and retaining them in the paper. Optical properties of paper and strategies to maintain paper strength at higher filler levels are considered. The goal of this review is to provide background both for engineers working to make their paper products more competitive and for researchers aiming to achieve effects beyond the current state of the art.