NC State
  • Editorialpp 6902-6903Wu, D., Qian, X., and Shen, J. (2017). "Macromolecular reorganization as a basis for converting cellulosic hydrogels into sustainable plastics," BioRes. 12(4), 6902-6903.AbstractArticlePDF

    The development of lignocellulose-derived sustainable plastics is an important strategy for a greener future. Cellulosic hydrogels, which are readily generated from a cellulosic source (e.g., wood pulp), can be converted into high-strength plastics by hot-pressing. In this process, cellulose macromolecules are fluidized and reassembled, leading to significant change of bonding interactions and structural characteristics. This interesting concept would open the door for new possibilities of bioproduct design.

  • Editorialpp 6904-6906Hubbe, M. (2017). "To repair or not to repair cracked wood," BioRes. 12(4), 6904-6906.AbstractArticlePDF

    If only wood could be defect-free, then the minimum strength of solid-wood beams and other structures could be much higher. Structural failures could be avoided, and-or less material might be required in some applications. Cracks in wooden structures can be filled with adhesives or with thermoplastic composite material. But to approach the intended strength of defect-free wood, it is necessary to use other strategies such as glued rods and surface patches. The ultimate answer may lie in better species selection, tree breeding, forestry strategies, lumber cutting practices, and lumber drying practices to avoid cracks in the first place.

  • Researchpp 6907-6923Carvalho, D. M., and Colodette, J. L. (2017). "Comparative study of acid hydrolysis of lignin and polysaccharides in biomasses," BioRes. 12(4), 6907-6923.AbstractPDF

    Effects of different acid hydrolysis conditions were studied relative to the chemical transformations of lignin in eucalyptus, sugarcane bagasse, and sugarcane straw, and on the transformations of multiple polysaccharides in eucalyptus. The acid hydrolysis using 12 mol/L sulfuric acid followed by acid hydrolysis using approximately 0.41 mol/L sulfuric acid was used as the reference for the lignin and sugar analysis. During acid hydrolysis, the relative amount of lignin increased with longer reaction times and/or greater acid concentrations for all biomasses. The overestimation of lignin in harsher acidic conditions resulted from the summation of lignocellulosic-derivatives (pseudo-lignin) together with lignin itself. Lignin reactions (dissolution/deposition) for bagasse and straw occurred in a greater extent than for eucalyptus, considering similar conditions of acid hydrolysis. The sugar transformation during acid hydrolysis was also investigated for eucalyptus. The sugar content quantified in eucalyptus decreased as the acid concentration and/or reaction time in the second hydrolysis increased. Glucose, galactose, and mannose were more resistant to harsher acidic conditions than xylose and arabinose. However, the most severe conditions (121 ºC, 90 min, and 6.15 mol/L H2SO4) caused complete sugar degradation.

  • Researchpp 6924-6955Bekiroğlu, S., Mertoğlu Elmas, G. M., and Yagshiyev, Y. (2017). "Contribution to sustainability and the national economy through recycling waste paper from Istanbul’s hotels in Turkey," BioRes. 12(4), 6924-6955.AbstractPDF

    Obtaining cellulose from recyclable waste paper contributes to the sustainability of forest resources, water and energy savings, and the reduction of environmental pollution. However, waste paper collected under inappropriate conditions for recycling can be degraded in a short time, thus becoming economically useless. This study examined the factors affecting source-separated collection processes of waste paper in Istanbul hotels, as well as the correlation among these factors. The economic value of the assumed benefits of source-separated waste paper was also calculated. To achieve these objectives, various inputs and methods were used, including the percent tabulation technique and the chi-square independence test. As a result, it was determined that 70% of managers and employees of Istanbul hotels were sensitive to recycling waste paper, but they were not aware of the entire benefits of waste paper recycling. It was also determined that because of waste paper recycling, 18 thousand trees, 5 million kWh of electricity, 3 thousand tons of water, and 1.3 thousand tons of fuel oil were saved, and the generation of 27 thousand tons of CO2 was prevented annually. Hotels in Istanbul provide the economy with an annual average of 752 tons of waste paper, which corresponds to 78% of the foreign trade deficit of Turkey’s paper and paper products sector in the last five years.

  • Researchpp 6956-6970Wang, X., Liu, Z., Wang, S., Kong, F., Yang, G., Fatehi, P., and Lucia, L. A. (2017). "Enhancing the alkaline peroxide mechanical pulp strength by cationization with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride," BioRes. 12(4), 6956-6970.AbstractPDF

    Alkaline peroxide mechanical pulp (APMP) is a newly emerging high yield pulp (HYP) with numerous advantages. However, the drawback of the alkaline peroxide mechanical pulp from untreated plant biomass is its poor network strength. In this work, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) modification was proposed to enhance pulp network strength by fiber surface modification that could enhance fiber bonding. Three factors were analyzed by response surface methodology (RSM) to optimize treatment conditions based on factorial designs. The results showed that the optimal conditions were CHPTAC dosage of 0.8% (oven-dry pulp), NaOH dosage of 0.1% (oven-dry pulp), and pulp concentration of 8%. The modified pulp fibers were characterized by elemental analysis, charge density analysis, Fourier transform infrared spectroscopy (FTIR), thermal gravity analysis (TGA), and internal bond strength analysis, as well as zero span tensile analysis. The physical strength of the modified APMP pulp was increased in terms of tensile index, tear index, and burst index. After modification, the tensile index, tear index, and burst index increased by 35.3%, 29.2%, and 16.7% respectively. The internal bonding strength increased by 144.4%; however, the increase of zero span tensile index of modified pulp fibers was insignificant.

  • Researchpp 6971-6983Altuntas, E., Narlioglu, N., and Alma, M. (2017). "Investigation of the fire, thermal, and mechanical properties of zinc borate and synergic fire retardants on composites produced with PP-MDF wastes," BioRes. 12(4), 6971-6983.AbstractPDF

    Synergic effects of different fire retardant compounds and zinc borate on wood-plastic composites filled with polypropylene (PP) and medium-density fiberboard (MDF) waste fibers were investigated. For this purpose, zinc borate, synergic compounds (antimony trioxide, ammonium phosphate, and magnesium hydroxide), and a coupling agent, i.e., maleic anhydride-grafted polypropylene (MAPP), were used in the production of wood-plastic composites (WPCs). The composite samples were characterized in terms of the burning rate and limiting oxygen index (LOI) analyses, thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC) along with mechanical tests, i.e., flexural properties, tensile properties, elasticity modulus, and impact strength. It was found that the synergic influence of the combination of zinc borate, antimony trioxide, and magnesium oxide on WPCs increased the heat resistance according to the burning rate, LOI, TGA, and DSC tests. Also, the mechanical properties of the WPCs decreased slightly, but their elasticity modulus increased.

  • Researchpp 6984-7001Gopinathan, P., Subramanian, K., Paliyath, G., and Subramanian, J. (2017). "Genotypic variations in characteristics of nano-fibrillated cellulose derived from banana pseudostem," BioRes. 12(4), 6984-7001.AbstractPDF

    A laboratory study was undertaken to extract nano-fibrillated cellulose (NFC) from the pseudostem (a waste from the fruit harvest) of two commercial banana cultivars (‘Grand Naine’ and ‘Poovan’) in Tamil Nadu using a novel approach: a one-step method with a bleaching agent and alkali-free acid hydrolysis coupled with ultrasonication. The acid hydrolysis was performed using nitric acid and acetic acid (1:10 ratio). The treatment was effective in the depolymerization and defibrillation of banana pseudostem fiber and in the formation of NFC, which was confirmed by several physico-chemical techniques. The average diameters of the nanofibrils were 6 to 8 nm and 4 to 6 nm for ‘Grand Naine’ and ‘Poovan’, respectively. The XRD analysis revealed an increased cellulose crystallinity of almost 20% in the NFC compared with the respective raw banana fibers. The Fourier transform infrared (FT-IR) spectroscopy and thermal gravimetric analysis (TGA) confirmed the absence of lignin, hemicelluloses, and pectin in the nano-fibrillated samples. The thermal analysis showed the increased thermal stability of the NFC.

  • Researchpp 7002-7015Huang, W., Wang, E., Chang, J., Wang, P., Yin, Q., Liu, C., Zhu, Q., and Lu, F. (2017). "Effect of physicochemical pretreatments and enzymatic hydrolysis on corn straw degradation and reducing sugar yield," BioRes. 12(4), 7002-7015.AbstractPDF

    Straw lignocelluloses were converted to reducing sugar for possible use for bioenergy production via physicochemical pretreatments and enzymatic hydrolysis. The experiment was divided into 2 steps. The first step focused on breaking the crystal structure and removing lignin in corn straw. The lignin, hemicellulose, and cellulose degradation rates observed were 92.2%, 73.7%, and 4.6%, respectively, after corn straw was treated with sodium hydroxide (3% w/w) plus high-pressure steam (autoclave), 74.8%, 72.5%, and 4.3% after corn straw was treated with sodium hydroxide (8%, w/w) plus wet steam explosion, compared with native corn straw (P < 0.05). The second step was enzymatic hydrolysis for the pretreated straw. The enzymatic hydrolysis could yield 576 mg/g reducing sugar and significantly degrade cellulose and hemicellulose contents by 93.3% and 94.4% for the corn straw pretreated with sodium hydroxide plus high-pressure steam. For the corn straw pretreated with sodium hydroxide plus wet steam explosion, the enzymatic hydrolysis could yield 508 mg/g reducing sugar, and degrade cellulose and hemicellulose contents by 83.5% and 84.2%, respectively, compared with the untreated corn straw (P<0.05). Scanning electron microscopy showed that the physicochemical pretreatments plus enzymatic hydrolysis degraded corn straw to many small molecules. Thus, physicochemical pretreatments plus enzymatic hydrolysis converted lignocellulose to reducing sugar effectively.

  • Researchpp 7016-7031Záborský, V., Borůvka, V., Kašičková, V., and Ruman, D. (2017). "Effect of wood species, adhesive type, and annual ring directions on the stiffness of rail to leg mortise and tenon furniture joints," BioRes. 12(4), 7016-7031.AbstractPDF

    The effects of selected factors, wood species (Fagus sylvatica L. and Picea abies L.), type of joint (haunched mortise and tenon, and haunched dovetail mortise and tenon), tenon thickness (one-third and half-joint thickness), type of adhesive (polyvinyl acetate and polyurethane adhesive), loading type (compressive and tensile), and direction of the annual rings were evaluated relative to the elastic stiffness. The testing samples were loaded by bending moment with tensile and compressive forces in the angular plane. The wood species, type of joint, tenon dimension, and type of adhesive all had a statistically significant effect on the elastic stiffness. However, the interaction of those factors was statistically insignificant. The loading type and direction of the annual rings did not have a significant effect on the elastic stiffness. For spruce, the use of mortise and tenon with a toothed feather (MTTF) was found to be disadvantageous, whereas the use of a toothed feather was favorable for beech. Half thickness of the joint was always an advantage, such that the stiffness increased. For spruce joints, the type of glue was not important, whereas for beech, the stiffness of joints glued with PVAc was significantly higher than with PUR adhesive.

  • Researchpp 7032-7040Nosek, R., Holubcik, M., Jandacka, J., and Radacovska, L. (2017). "Analysis of paper sludge pellets for energy utilization," BioRes. 12(4), 7032-7040.AbstractPDF

    The pulp and paper industry in Europe produces over 11 million tons of waste per year. Given high landfill operational costs, thermal co-processing with biomass may be a viable management and valorisation option for such wastes. In this work, the analysis of biomass (wood sawdust), mixture of primary and secondary pulp mill sludge and their respective blends (50 wt.%, 60 wt.%, 70 wt.% of sludge) was assessed by thermogravimetric analysis. One of the possibilities to ensure valorisation of paper pulp mill sludge is its combustion in the form of pellets containing a different amount of sludge. Production of pellets samples was realised on laboratory experimental device. The measurements showed that increasing the content of paper sludge in the produced pellets reduced the calorific value and increased the ash content. This research deals also with the effect of paper sludge on the ash melting temperatures. The results indicated that a higher content of paper sludge in the pellets increased the ash melting temperatures. This advantage of paper sludge can be utilized in co-combustion of biomass with a low ash melting temperature.

  • Researchpp 7041-7055Wei, Y., Wang, M., Zhang, P., Chen, Y., Gao, J., and Fan, Y. (2017). "The role of phenolic extractives in color changes of locust wood (Robinia pseudoacacia) during heat treatment," BioRes. 12(4), 7041-7055.AbstractPDF

    To investigate the effects of phenolic extractives on the discoloration of black locust wood (Robinia pseudoacacia) during heat treatment, phenolic compounds were extracted using an accelerated solvent extraction. The main components of the phenolic extractives were analyzed. The phenolic compounds were heat treated at 120 and 140 °C in nitrogen, oxygen, and saturated steam. The results showed that the a* values shifted toward red and the b* values shifted toward yellow after the heat treatment. The changes in the color parameters were more pronounced when the samples were treated at 140 °C in saturated steam compared with treatment at 120 °C in oxygen or nitrogen atmosphere. During heat treatment, hydroxyl groups in the phenolic components were oxidized to form carbonyl groups, or the adjacent hydroxyl groups formed quinoid structures. It was possible that the sample underwent condensation reactions to produce conjugated double-bond structures that led to the increase in color parameters.

  • Researchpp 7056-7068Altuntas, E., Yilmaz, E., Salan, T., and Alma, M. H. (2017). "Combined effect of zinc borate and coupling agent against brown and white rot fungi in wood-plastic composites," BioRes. 12(4), 7056-7068.AbstractPDF

    Fungal resistance was investigated for wood-plastic composites (WPCs) containing zinc borate, maleic anhydride grafted polyethylene (MAPE) as a coupling agent, wood fiber (Pinus sylvestris), and high-density polyethylene (HDPE). Decay resistance, water absorption, and surface hardness (Shore D) of the WPCs were tested. The reinforced wood-plastic composites were exposed to brown-rot fungus (Coniophora puteana, Postia placenta) and white-rot fungus (Trametes versicolor) in agar tests. The results showed that zinc borate improved the decay resistance of the WPCs against brown and white rot fungus according to their weight losses. Moreover, the water absorption and surface hardness tests indicated that the physical properties of the composites were weakened after fungal decay tests. The usage of MAPE and zinc borate alone or together was effective against both rot fungus species in WPCs. The synergy of 1% zinc borate and 3% MAPE in WPCs could considerably increase the fungal attack resistance. Scanning electron microscopy (SEM) revealed that both brown and white rot fungus attacked the surface of WPCs samples without both MAPE and zinc borate.

  • Researchpp 7069-7083Brandão, T. S. O., Pinho, L. S., Hughes, A. F. S., Souza, J. L., Rosa, C. A., Teshima, E., Brandão, H. N., and David, J. M. (2017). "Characterization of the jambolan (Syzygium cumini L.) fruit wine processing," BioRes. 12(4), 7069-7083.AbstractArticlePDF

    Yeasts were isolated and the alcohol genic features were tested for their direct use in the wine processing of jambolan. In addition, changes in the total phenolic compounds during the maceration-fermentation process were investigated. Yeasts were selected from the spontaneous fermentation of the jambolan pulp, and the feasibility and fermentative production of its alcohol was tested. Out of the group of yeasts selected, the one that stood out was subjected to DNA extraction and sequencing. The yeast was identified as Saccharomyces cerevisiae, and the fermentation tests came back as 80.6% and the ethanol production yield was 8.35%. The chemical composition of raw materials was analyzed by spectrophotometrics and high performance liquid chromatography (HPLC) methods. The overall results also indicated that the evolution during the maceration-fermentation process of phenolic compound concentrations was influenced by the varietal factor. The concentration of phenolic compounds increased 30%, while the concentration of tannins increased 27.4% in the final product.

  • Researchpp 7084-7095Ji, X., Ma, H., Tian, Z., Lyu, G., Fang, G., Chen, J., and Saeed, H. A. M. (2017). "Production of xylose from diluted sulfuric acid hydrolysis of wheat straw," BioRes. 12(4), 7084-7095.AbstractPDF

    The objectives of this study were to generate fermentable xylose by sulfuric acid hydrolysis of wheat straw and investigate the effect of hemicellulose removal on the physical and chemical properties of the unhydrolyzed solid residue (USR). Different reaction conditions, including concentration of sulfuric acid (COS), temperature, and time, were tested for their effects on the yield of xylose and the USR. The ideal hydrolysis conditions for xylose production were 0.5% of COS at 140 °C for 90 min, with the xylose yield of 0.185 g/g wheat straw. The Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses showed that the acid hydrolysis only caused slight changes in the functional groups and the crystal form of wheat straw at mild conditions, while higher temperature or higher COS exacerbated these changes.

  • Researchpp 7096-7106Chen, Q., Mi, T., Chen, G., and Li, Y. (2017). "Green synthesis of nano-silver particles using plant active substance from lemongrass extract," BioRes. 12(4), 7096-7106.AbstractPDF

    Biosynthesis of nanoparticles by plant extracts is currently under exploitation. Plant extracts are very cost effective and eco-friendly and thus can be an economic and efficient alternative. This study investigates the mechanism of preparation of nano-silver using a plant active substance from lemongrass extract. The lemongrass ethanol extract was prepared using an ultrasonic cell crusher. Spherical silver nanoparticles were prepared with lemongrass extract and silver nitrate. The reaction mechanism of the preparation of nano-silver by plant extracts was analyzed by infrared and X-ray photoelectron spectrometer (XPS) measurements. The uniform and stable spherical silver nanoparticles with an average particle size of 22.99 nm were synthesized. Amide compounds in plant extracts may act as reductants and protective agents. The biomass of plants produces their nanomaterials through a process called biomineralisation. Thus, plant active substances can be used widely, and biological methods are completely feasible and worth studying for the chemical procedures, which are environmentally friendly and convenient.

  • Researchpp 7107-7117Mirski, R., Dziurka, D., and Derkowski, A. (2017). "Dimensional stability of oriented strand boards with external layers made of non-strand chips: Changes in board length," BioRes. 12(4), 7107-7117.AbstractPDF

    The dimensional stability of oriented strand boards (OSB) was evaluated in terms of the changes in their length, static bending strength, and modulus of elasticity. Outer layers of these boards were manufactured from particles other than strand chips. The boards were exposed to an air relative humidity of 30%, 65%, or 85%. Dimensional alterations were determined separately for absorption (from 65% to 85% RH) and desorption (from 65% to 30% RH) changes. Changes in the mechanical properties of the boards were evaluated after they underwent two cycles of the conditioning process and were compared with the baseline values. The study implied that relative changes in the mechanical properties and length increased when there was a reduction in the size of chips that formed the outer layers. A linear relationship was established between the relative changes in the board length determined for the axis that was more susceptible to deformation and the modulus of elasticity. These changes were inversely proportional to the value of the modulus of elasticity.

  • Researchpp 7118-7132Chee, S. S., Jawaid, M., and Sultan, M. T. H. (2017). "Thermal stability and dynamic mechanical properties of kenaf/bamboo fibre reinforced epoxy composites," BioRes. 12(4), 7118-7132.AbstractPDF

    An increased awareness of environmental concerns has increased the need for innovation to produce high performance engineering materials with natural renewable resources. In this study, 3 types of natural fibre (mat form) reinforced epoxy composites were prepared by the hand lay-up method, namely, kenaf (K)/Epoxy, bamboo (B)/Epoxy, and bamboo charcoal (BC)/Epoxy. The thermal stability of the specimens was investigated by thermogravimetric analysis (TGA) and the dynamic mechanical properties. Viscous elastic behaviour of the specimens was investigated via a dynamic mechanical analyzer (DMA). The TGA results revealed that the BC/Epoxy composite showed the highest thermal stability compared to K/Epoxy and B/Epoxy with the highest initial and final decomposition temperature at 348 °C and 463 °C, respectively. It also showed the highest charcoal content at 11.5%. From the DMA results, the K/Epoxy composite showed better dynamic mechanical properties with the highest complex modulus (E*) strength and the lowest damping behaviour (peak height of Tan δ). The DMA analysis also revealed that the glass transition temperature of the composites fell between 60 °C to 90 °C. This preliminary study may give a new path to develop a novel hybrid composite that offers unique properties unachievable in a single material system.

  • Researchpp 7133-7144Chin, S. X., Chook, S. W., Chia, C. H., Lau, K. S., Zakaria, S., and Tasirin, S. M. (2017). "Graphene oxide as support and regenerative substrate for lead ions in catalytic conversion of lactic acid," BioRes. 12(4), 7133-7144.AbstractPDF

    Graphene oxide (GO) was used as a catalyst support and for regeneration of a homogeneous catalyst in the catalytic conversion of glucose to lactic acid (LA). First, a solid base catalyst was prepared through the adsorption of Pb2+ ions by GO through ionic interaction with oxygenated groups of GO. The collected GO-Pb catalyst was characterized, demonstrating the successful loading of Pb2+ onto GO sheets using FTIR and XPS. The GO-Pb catalyst was subsequently used for the conversion of glucose into LA. A maximum LA yield of approximately 30% was achieved in 30 min. The catalyst demonstrated the ability to be used for at least five cycles. In contrast, the leached Pb2+ ions during the hydrothermal process were regenerated through adsorption with fresh GO. The regenerated catalyst demonstrated the possibility of the regenerated Pb2+ ions for further catalytic conversions of lactic acid. This study could be essential to produce valuable chemicals through the use of heterogeneous catalysts that are produced via a simple and environmental benign process.

  • Researchpp 7145-7160Edhirej, A., Sapuan, S. M., Jawaid, M., and Zahari, N. I. (2017). "Tensile, barrier, dynamic mechanical, and biodegradation properties of cassava/sugar palm fiber reinforced cassava starch hybrid composites," BioRes. 12(4), 7145-7160.AbstractPDF

    The hybrid composite was prepared from cassava bagasse (CB) and sugar palm fiber (SPF) by casting technique using cassava starch (CS) as a matrix and fructose as a plasticizer. The chemical composition and physical properties of SPF and CB were studied in this work. SPF was added at different loadings of 2, 4, 6, and 8% dry starch to the CS/CB composite films with 6% CB. The addition of SPF influenced the hybrid properties. It was observed that the addition of 6% SPF to the composite film increased the tensile strength and modulus up to 20.7 and 1114.6 MPa, respectively. Also, dynamic-mechanical properties of the hybrid composites were investigated using a DMA test. The incorporation of SPF increased the storage modulus (E’) value from 0.457 GPa of CS to 1.490 GPa of CS-CB/SPF8 hybrid composite film. Moreover, the incorporation of SPF slightly decreased the water vapor permeability (WVP) compared to the CS/CB composites film. It can be concluded that the incorporation of SPF led to changes in cassava starch composite film properties, potentially improving the bio-degradability, WVP, and mechanical properties of the film. Based on its excellent properties, CB/SPF-CS hybrid composite films are suitable for various purposes such as packaging, automotive, and agro-industrial applications, at lower cost.

  • Researchpp 7161-7177Altuntas, E., Yilmaz, E., Salan, T., and Alma, M. H. (2017). "Biodegradation properties of wood-plastic composites containing high content of lignocellulosic filler and zinc borate exposed to two different brown-rot fungi," BioRes. 12(4), 7161-7177.AbstractPDF

    The decay resistance of zinc borate-reinforced wood-plastic composites (WPCs) was studied against two types of brown-rot fungi (Rhodonia placenta and Coniophora puteana). The WPCs with 70% wood fibers (Pinus sylvestris L.) were reinforced with 1% and 2% zinc borate. The reinforced WPCs were exposed to a decay test according to the EN 113 (1996) standard. The composite samples were characterized by their weight losses and water absorption capacity (WAC) as well as by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The weight losses and WAC results showed that zinc borate improved the decay resistance of the WPCs to a certain degree against brown rot fungi. The FTIR and SEM results showed that the brown rot fungi attacked the WPCs. It was concluded that the use of 1-2% zinc borate provided resistance to fungal attack on WPCs to a certain degree.

  • Researchpp 7178-7194Löwe, A., Hauptmann, M., and Majschak, J. P. (2017). "The effect of ultrasonic oscillation on the quality of 3D shapes during deep-drawing of paperboard," BioRes. 12(4), 7178-7194.AbstractPDF

    In this publication, the ultrasonic-assisted deep-drawing of fiber-based materials, whose implementation was presented in Löwe et al. (2016), was studied in detail. Methods were developed for measuring the properties of deep-drawn cups, including cup stability, shape deviation, and surface quality. The relationship between these properties and the process parameters were determined with a design of experiment, which allows the user to adjust the cup properties in order to optimize them.

  • Researchpp 7195-7204Stajic, M., Ćilerdžić, J., Galić, M., Ivanović, Ž., and Vukojević, J. (2017). "Lignocellulose degradation by Daedaleopsis confragosa and D. tricolor," BioRes. 12(4), 7195-7204.AbstractPDF

    The properties and capacities of the ligninolytic enzymes of Daedaleopsis spp. are still unknown. This is the first study on the effect of plant residues and period of cultivation on the properties of Mn-oxidizing peroxidases and laccases of D. confragosa and D. tricolor, as well as their ligninolytic potentials. Wheat straw was the optimal carbon source for synthesis of highly active Mn-dependent peroxidases (4126.9 U/L in D. confragosa and 2037.9 U/L in D. tricolor). However, laccases were the predominant enzymes, and the best inducer of their activity (up 16000.0 U/L) was cherry sawdust. Wheat straw was the most susceptible plant residue to the effect of the enzymes, and extent of lignin degradation was 43.3% after 14 days of fermentation with D. tricolor. However, D. confragosa was a more effective lignin degrader, as it converted even 21.3% wheat straw lignin on the 6th day of cultivation. The results of the study clearly showed that delignification extent depends on mushroom species and on the type of plant residue, which is extremely important for potential use in biotechnological processes.

  • Researchpp 7205-7217Xu, Y., Wang, B., Shen, Y., Wu, J., Feng, L., and Yu, H. (2017). "Effect of softening treatment on cutting force during slicing the veneers of common fast-growing wood," BioRes. 12(4), 7205-7217.AbstractPDF

    To verify the effect of softening treatment on the cutting force during slicing of veneers, an experiment was performed using a veneer slicer with steam injection heating function. Several conditions were set to soften the experimental materials of poplar (Populus L.), eucalyptus (Eucalyptus robusta Smith), pine (Pinus massoniana Lamb.), and Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.). The cutting force was detected by the YE7600 signal analysis system. The results showed that the cutting force increased with increased slicing thickness. The cutting force was observed to follow the order, from high to low for the conditions of being soaked in cold water, then steam heated, water-poached, and steam heated again. Compared to the case of non-steam heating, the effect of steam heating on reducing the cutting force was satisfactory, and the maximum decrease percentage reached 83.1%. The cutting force was positively related to the wood density and hardness, and the cutting stroke had a great influence on the cutting force. After being softened, the four kinds of fast-growing wood were sliced into veneers with ≤ 6 mm thickness, and the cutting force was generally no more than 6850 N.

  • Researchpp 7218-7227Björngrim, N., Fjellström, P. A., and Hagman, O. (2017). "Factory-mounted and retrofit passive resistance sensors adapted to monitor moisture content in timber bridges," BioRes. 12(4), 7218-7227.AbstractPDF

    The biggest threats to the longevity of a timber bridge are rot and decay. Wood protection by design, inspections, and monitoring of the bridge for elevated moisture content will ensure that the full service life of the structure can be achieved. Today’s sensors for moisture content measurements are limited in their functionality and range. This paper presents a sensor that can be both factory installed and retrofitted, which can measure the moisture content through the cross-section of the member in a timber bridge. The sensor has been mounted on Sundbron bridge during manufacturing and retrofitted on Gislaved bridge. The ensuing measurements helped to adjust a design flaw on Gislaved bridge. Monitoring of Sundbron showed that the bridge deck dried up after the bridge had been exposed to sleet and snow during the on-site assembly of the stress laminated bridge deck.

  • Researchpp 7228-7240Manyuchi, M. M., Frank, R., Mbohwa, C., and Muzenda, E. (2017). "Potential to use sorghum brewers spent grains as a boiler fuel," BioRes. 12(4), 7228-7240.AbstractPDF

    The potential of using sorghum brewers spent grain (BSG) was examined for the production of bioelectricity. A local brewery company, with a production capacity of 24 tons per day of sorghum brewers spent grain as biomass waste, was used as a source of boiler fuel. After a full proximate analysis, the sorghum brewers spent grain had an average calorific value of 12.6 MJ/kg whilst coal had 19.9 MJ/kg. In addition, the BSG had a fixed carbon content of 41.6%. This indicated that it was feasible to generate electricity using sorghum brewers spent grain as a source of fuel just like coal; however the moisture content of the BSG must be controlled at minimum levels to attain high calorific values. An assumed feed rate of 1100 kg/h BSG being fed, operation at 86% efficiency, maximum pressure of 9 bars, and a steam output of 1689 kg/h were designed to supply a one megawatt (MW) turbine generator. An economic analysis was done with a total investment cost of USD$ 3.4 million, a payback period of 3.7 years, and a return on investment of 27.4%. Sorghum BSG can be provided as an alternative source of bioelectricity for the brewery industry.