NC State
  • Researchpp 3857-3868Wu, P., Ma, Y., Chen, Y., Zhang, Y., and Wang, H. (2014). "Vibration-assisted compaction of biomass," BioRes. 9(3), 3857-3868.AbstractArticlePDF

    The biomass extrusion process for making biomass briquettes or logs normally requires large amounts of energy to overcome the springback of the material and friction with the die surface. Also, the products readily expand and disintegrate because of the retention of internal stresses. In this study, tests on vibration-assisted compaction of biomass were performed as a method to reduce the energy requirement and to improve product quality. An experimental set-up was designed and manufactured by which vibration-assisted compaction was exerted on a die surface. Tests on compaction to form upgraded biomass logs with and without the assistance of vibration were conducted and compared. The results showed that the vibration applied on a die surface can reduce the compression energy requirements and improve product quality.

  • Researchpp 3869-3882Wang, Z., Wang, Z., Wang, B. J., Wang, Y., Liu, B., Rao, X., Wei, P., and Yang. Y. (2014). "Dynamic testing and evaluation of modulus of elasticity (MOE) of SPF dimensional lumberAbstractArticlePDF

    The key objective of this work was to develop a cost-effective and reliable non-destructive testing (NDT) method to measure lumber modulus of elasticity (MOE). Test samples comprised 300 pieces of randomly selected imported Canadian 2”×6” SPF (Spruce – lodgepole Pine – alpine Fir) dimensional lumber. This work first adopted a modal test to achieve a free suspension for a subsequent vibration test. Then, the first-order natural frequency of 300 SPF dimensional lumber specimens was measured by the transient excitation frequency method, based on which MOE was then calculated. The results were also validated by a stress wave method using a Hitman tool. The measured lumber MOE data were further fitted using a Weibull distribution. The results showed that the MOE of SPF dimensional lumber followed either a three-parameter Weibull distribution or a normal distribution. It was estimated that the probability that the MOE of this SPF dimensional lumber was less than 8,000 MPa was about 13.8% and 13.6%, respectively, using the above two distributions.

  • Researchpp 3883-3900Togay, A., and Ergin, E. (2014). "Determination of some physical attributes for wooden construction elements strengthened with woven wire fiberglass," BioRes. 9(3), 3883-3900.AbstractArticlePDF

    This study designed composite wooden construction elements strengthened with woven wire fiberglass netting and determined the technical attributes. Scots pine (Pinus sylvestris L.) was used in wooden layers, and woven wire fiberglass netting was used in intermediate layers. Layers were pressed with polyvinyl acetate (PVAc) D3 and Desmodur-VTKA adhesives to form 7 solid 13-layer laminated composite specimens. Experiments on 95 specimens determined density, bonding strength, bending resistance, and compression strength; solid and solid laminated wooden materials were tested and compared. BS EN 204 and BS EN 205 standards were complied with for bonding strength tests, TS 5497 EN 408 was used for densities, and TS 549 EN 408 was followed for bending resistance and compressive strength. Most factors, except for intermediate layer material in compressive strength and bending resistance tests perpendicular to the glue line, did not cause significant differences. Variables (adhesive, intermediate layer material) used for determining bending strength parallel to the glue line were effective. Polyurethane adhesive increased resistance to bending parallel to the glue line. These composite wooden construction elements supported with woven wire fiberglass netting could be advantageous for applications that require high bending resistance perpendicular to the glue line. However, these composites do not hold a compressive strength advantage.

  • Researchpp 3901-3908Zhou, Y., Min, D. Y., Wang, Z., Yang, Y., Kuga, S. (2014). "Cellulose esterification with octanoyl chloride and its application to films and aerogels," BioRes. 9(3), 3901-3908.AbstractArticlePDF

    Homogeneous esterification of cellulose with octanoyl chloride (a long-chain fatty acid) was investigated in lithium chloride/N,N-dimethyl acetamide (LiCl/DMAc) medium. Cellulose was readily esterified by the octanoyl chloride, as shown by 1H NMR analysis. The effects of the ratio of octanoyl chloride to cellulose hydroxyl groups, the reaction temperature, and the reaction time on the yield and degrees of substitution (DS) of cellulose esters (CEs) were investigated. CEs with high DS (2.2) were achieved after 8 h at 100 °C with a 1.6 to 1.8 of molar ratio of octanoyl chloride to cellulose hydroxyl groups. Furthermore, hydrophobic, fully transparent CE films and aerogels were prepared using CE tetrahydrofuran (THF) solutions. The CE aerogels exhibited high porosity and were formed with evenly distributed porosity, as revealed by scanning electron microscopy (SEM).

  • Researchpp 3909-3918Ma, M. G., Deng, F., Yao, K., and, Tian, C. H. (2014). "Microwave-assisted synthesis and characterization of CaCO3 particles-filled wood powder nanocomposites," BioRes. 9(3), 3909-3918.AbstractArticlePDF

    The purpose of this study was to develop a rapid and green method for the synthesis of biomass-based materials. A microwave-assisted method was used for the preparation of CaCO3 particles-filled wood powder nanocomposites, which involve natural cellulosic materials, CaCO3, and microwave heating. Dewaxed wood powder was pretreated in the NaOH/urea solution. The urea acts as part of the CO32- source and provides a basic condition for the synthesis of CaCO3. The influences of reaction parameters such as the heating time and the addition of (NH4)2SO4 on the products were investigated by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The experimental results demonstrated that the heating time had an effect on the crystallinity and morphology of the nanocomposites. In addition, the presence of (NH4)2SO4 played an important role in the morphology and dispersion of CaCO3 in the nanocomposites.

  • Researchpp 3919-3938Trischler, J., and Sandberg, D. (2014). "Monocotyledons in particleboard production: Adhesives, additives, and surface modification of reed canary grass," BioRes. 9(3), 3919-3938.AbstractArticlePDF

    As a supplier to the furniture industry, the particleboard industry is searching for opportunities to reduce costs, weight, and formaldehyde emissions. One such opportunity is to use monocotyledons such as straw and hemp, as well as grasses like reed canary grass. A major problem when using reed canary grass or other monocotyledons in combination with wood is the difference in their surface properties, leading to poor reactivity and wettability with adhesives such as melamine urea formaldehyde. To this end, either the surface of the particles must be modified in some way, or different adhesives must be used. The purpose of this paper is to present adhesives, surfactants, coupling agents, and pre-treatment methods that can be used in combination with monocotyledons to improve compatibility with wood. Some of the methods have been tested on reed canary grass. The results show a wide range of strength values for the joint between wood and untreated or pre-treated reed canary grass glued with different adhesives, with and without a surfactant and a coupling agent. Isocyanate-based adhesives provided relatively strong bonds, and polyvinyl acetate, acryl, and epoxy adhesives were also effective. The most effective method was pre-treatment followed by adhesives in combination with a coupling agent.

  • Researchpp 3939-3954Ma, Y., Wang, Q., Sun, X., Wang, X., Su, W., and Song, N. (2014). "A study on recycling of spent mushroom substrate to prepare chars and activated carbon," BioRes. 9(3), 3939-3954.AbstractArticlePDF

    (SMS) via pyrolysis. It was found that as the pyrolysis temperature increased from 400 to 700 °C, the char yield decreased from 45.10 to 33.79 wt.% and the higher heating value increased from 17.32 to 22.72 MJ/kg. The largest BET surface area (13 m2/g) was created at 500 °C. Hydrogen atoms were continuously lost during pyrolysis, whereas oxygen atoms were difficult to eliminate. Whewellite, calcite, lime, and quartz were the minerals in the chars, and their forms and crystallinity changed with changing pyrolysis temperature. Activated carbon with a BET surface area of 1023 m2/g and a total pore volume of 0.595 cm3/g was obtained from the char prepared at 500 °C. Its characteristics were studied by N2-adsorption, Fourier transform infrared spectroscopy ( ), and X-ray diffraction (XRD). The pyrolysis and KOH-activation processes were investigated by thermogravimetric analysis (TGA). The results showed that the pyrolysis of SMS occurred primarily between 217 and 375 °C and that the energies needed for the pyrolysis reactions were relatively low due to the prior mushroom cultivation. Furthermore, lignin was incompletely decomposed in the char prepared at 500 °C, and KOH suppressed tar evolution and reduced the energy needed to decompose the residual lignin during activation.

  • Researchpp 3955-3967Song, J., Yang, W., Fu, F., and Zhang, Y. (2014). "The effect of graphite on the water uptake, mechanical properties, morphology, and EMI shielding effectiveness of HDPE/bamboo flour composites," BioRes. 9(3), 3955-3967.AbstractArticlePDF

    This goal of this work was to study the effect of graphite on the water uptake, mechanical properties, morphology, and electromagnetic interference shielding effectiveness (EMI SE) of HDPE/Bamboo flour composites using the material mechanical testing machine, scanning electron microscopy (SEM), and EMI shielding apparatus. The water uptake of the composites was improved by graphite. Compared with the neat HDPE/bamboo composites, the flexural strength of the graphite-filled composites showed a small decrease, but the flexural modulus was enhanced greatly, indicating that graphite could effectively elevate the stiffness of the composites. An obvious result was that the toughness of composites was improved considerably by the graphite. The notched impact strength of the composites was increased from 5.18 to 9.0 KJ/m2 as graphite content was increased from 0 to 40 %. A large amount of graphite would increase the conductivity property and the EMI SE. The HDPE/bamboo composite with 40% of graphite exhibited electrical resistivity of 31.2 and the EMI SE of 20 dB in the frequency range of 30 – 3000 MHz.

  • Researchpp 3968-3976Wang, W., Yuan, T., and Cui, B. (2014). "Biological pretreatment with white rot fungi and their co-culture to overcome lignocellulosic recalcitrance for improved enzymatic digestion," BioRes. 9(3), 3968-3976.AbstractArticlePDF

    Three white rot fungi (Lenzites betulinus, Trametes orientalis, and Trametes velutina) as well as their respective paired cultures were used to pretreat Populus tomentosa for enhanced lignocellulosic degradation and enzymatic hydrolysis. Hemicellulose and cellulose were slightly degraded, while a maximum lignin degradation of 58% was caused by T. velutina during the 12-week cultivation. was as high as 41%, which was in line with the lignin loss at 2.2 times the control sample. Overall, the monocultures of white-rot fungi exhibited better degradation and saccharification of woody biomass than their co-culture. This can be attributed to the partial removal of lignin and hemicellulose, with an associated increase of cellulose accessibility to enzymes.

  • Researchpp 3977-3992Pérez-López, H., Gómez-Merino, F. C., Trejo-Téllez, L. I., García-Morales, S., and Rivera-Olivares , L. Y. (2014). "Agricultural lignocellulosic waste and volcanic rock combinations differentially affect seed germination and growth of pepper (Capsicum annuum L.)," BioRes. 9(3), 3977-3992.AbstractArticlePDF

    The effect of three substrates derived from combining agricultural lignocellulosic residues and a volcanic rock called tezontle (40/60; v/v) was tested on the germination and biomass production of five varieties of pepper (Capsicum annuum L.) grown under greenhouse conditions. The three substrates consisted of sugarcane bagasse and tezontle (SBTZ), coffee husk and tezontle (CHTZ), and filter cake from the clarification of sugarcane juice and tezontle (FCTZ), whereas the pepper varieties tested were Sven F1, Sympathy F1, Zidenka F1, Yolo Wonder, and California. Physical analyses of the substrates indicated that they had suitable properties, except for the percentage of readily available water, which was low in all the substrates. With regard to the chemical analyses, the best substrate was FCTZ. The highest germination percentage and the shortest time in which maximum germination was reached were also both found with the FCTZ substrate. Additionally, the greatest plant height and the highest shoot and biomass production were also recorded with the FCTZ substrate. In terms of varieties, those that responded best to the substrates were Sven F1, Sympathy F1, and Zidenka F1.