NC State
  • Researchpp 1417-1429Krilek, J., Kováč, J., and Kučera, M. (2014). "Wood crosscutting process analysis for circular saws," BioRes. 9(1), 1417-1429.AbstractArticlePDF

    This article deals with the influence of some cutting parameters (geometry of cutting edge, wood species, and circular saw type) and cutting conditions on the wood crosscutting process carried out with circular saws. The establishment of torque values and feeding power for the crosswise wood cutting process has significant implications for designers of crosscutting lines. The conditions of the experiments are similar to the working conditions of real machines, and the results of individual experiments can be compared with the results obtained via similar experimental workstations. Knowledge of the wood crosscutting process, as well as the choice of suitable cutting conditions and tools could decrease wood production costs and save energy. Changing circular saw type was found to have the biggest influence on cutting power of all factors tested.

  • Researchpp 1430-1444Liu, J., Ju, M., Wu, W., Liu, B., Zhan, L., Wu, M., Wang, P., Liu, Y., and Tong, S. (2014). "Lignocellulolytic enzyme production in solid-state fermentation of corn stalk with ammoniation pretreatment by Lentinus edodes L-8," BioRes. 9(1), 1430-1444.AbstractArticlePDF

    This study investigated the effect of ammoniation pretreatment of corn stalk (CS) with different temperatures, ammonia proportions, and processing times on lignocellulolytic enzyme production in solid-state fermentation (SSF) by Lentinus edodes L-8. The total N content and lignocellulose contents of ammoniated corn stalk were determined for analysis of the effect of ammoniation pretreatment on lignocellulose structure. The variation patterns of enzyme activity were analyzed according to the enzyme data determined every 2 days during the fermentation. A 4% w/w high-temperature ammoniation pretreatment had a significant effect on cellulase production, and the highest enzyme activity reached almost triple that of the control group. The results also showed that ammoniation pretreatment inhibited the generation of ligninases, such that ligninases appeared later and at lower activities in experimental groups compared to the control group.

  • Researchpp 1445-1455Wang, J., Zhang, H., Lei, M., Hu, H., and Pulkkinen, P. (2014). "Effects of tree age and bole section on pulpwood of Korean spruce (Picea koraiensis Nakai)," BioRes. 9(1), 1445-1455.AbstractArticlePDF

    Korean spruce (Picea koraiensis Nakai) is one of the most important wood resources for pulp and paper industry. However, a long production cycle is required for spruce to obtain mature timber, which may negatively influence the biomass production. In this study, fiber morphology, chemical composition, and pulping properties of Korean spruce with different tree ages and vertical locations were investigated. The results show that, along with the increase of tree ages, the contents of extractives, lignin, and pentosan increase to different extents. There are also some differences of pulping properties with different tree ages. As a pulpwood, the Korean spruce with tree ages of around 22 to 32 years is more suitable for kraft pulping, compared to that with 32-46 years. In addition, the middle segment of the bole had better pulp strength properties than the upper or lower bole segments.

  • Researchpp 1456-1471Huda, Azmul A. S. M., Koubaa, A., Cloutier, A., Hernández, R. E., and Fortin, Y. (2014). "Variation of the physical and mechanical properties of hybrid poplar clones," BioRes. 9(1), 1456-1471.AbstractArticlePDF

    The physical and mechanical properties of poplar clones largely determine their suitability for various end-uses, especially for high value-added applications. The main objective of this study was to determine the clonal variation of selected physical and mechanical properties of seven hybrid poplar clones grown at three sites in southern Quebec, Canada. Five trees per clone were randomly sampled from each site for wood properties measurement. Site had a significant effect on all measured properties except radial shrinkage. All properties of hybrid poplar wood showed significant interclonal variation, indicating the possibility of identifying clones with superior wood properties, especially for density, flexural modulus of rupture, and ultimate crushing strength. High heritability values for the studied properties indicated that these properties are under moderate to high genetic control. The genetic gain for these wood properties ranged from 2.0% to 13.5%.

  • Researchpp 1472-1487Mohamad Ibrahim, M. N., Lim, S. L., Ahmed-Haras, M. R., and Fayyadh, F. S. (2014). "Preparation and characterization of lignin graft copolymer as a filtrate loss control agent for the hydrocarbon drilling industry," BioRes. 9(1), 1472-1487.AbstractArticlePDF

    Lignin graft copolymer (LGC) was prepared using an addition polymerization technique that involved grafting a 2-acrylamido-2-methylpropane sulfonic acid (AMPS) monomer onto soda lignin (SL). The optimal polymerization conditions were found to be as follows: soda lignin, 2.0 g; initiator, 3% (w/w) potassium persulphate of SL; mass ratio of AMPS to SL, 1:2; reaction time, 7 h; and reaction temperature, 60 °C. The LGC was characterized using a Fourier transform infrared (FTIR) spectroscopy, a thermogravimetric analyzer (TGA), and gel permeation chromatography (GPC). The filtrate loss controlling ability of the LGC was evaluated using the American Petroleum Institute Recommended Practice 13-B 1 standard procedures. The results showed that the LGC has remarkable rheological and filtration controlling properties at both room temperature and high aging temperatures (190 °C).

  • Researchpp 1488-1497Ibrahim, D., and Lim, S.-H. (2014). "Utilization of palm kernel cake as a novel substrate for phytase production by Aspergillus niger USM Al1," BioRes. 9(1), 1488-1497.AbstractArticlePDF

    The present study was carried out to optimize the cultural conditions of phytase production by Aspergillus niger USM AI1 using palm kernel cake (PKC) as the substrate in a solid state fermentation (SSF) system. The optimized cultural conditions of 10 g of PKC with a particle size of ≤0.5 mm, an inoculum size of 1×105 spores/ mL, moisture content of 60% (v/w), and a mixing frequency of once every 48 hours produced 4.91±0.17 U/g dried substrate of phytase and 1.14±0.04 mg glucosamine/ g dried substrate of fungal growth. Maximum growth as well as enzyme production was recorded on the 4th day of cultivation at room temperature (30±2 ºC). The findings indicated that phytase production increased 171.3% after optimization (4.91±0.17 U/g dried substrate) compared to before optimization (1.81±0.16 U/g dried substrate). This study showed that PKC is a potential medium for phytase production in SSF.

  • Researchpp 1498-1518Kundu, A., Redzwan, G., Sahu, J. N., Mukherjee, S., Gupta, B. S., and Hashim, M. A. (2014). "Hexavalent chromium adsorption by a novel activated carbon prepared by microwave activation," BioRes. 9(1), 1498-1518.AbstractArticlePDF

    Microwave heating reduces the preparation time and improves the adsorption quality of activated carbon. In this study, activated carbon was prepared by impregnation of palm kernel fiber with phosphoric acid followed by microwave activation. Three different types of activated carbon were prepared, having high surface areas of 872 m2 g-1, 1256 m2 g-1, and 952 m2 g-1 and pore volumes of 0.598 cc g-1, 1.010 cc g-1, and 0.778 cc g-1, respectively. The combined effects of the different process parameters, such as the initial adsorbate concentration, pH, and temperature, on adsorption efficiency were explored with the help of Box-Behnken design for response surface methodology (RSM). The adsorption rate could be expressed by a polynomial equation as the function of the independent variables. The hexavalent chromium adsorption rate was found to be 19.1 mg g-1 at the optimized conditions of the process parameters initial concentration of 60 mg L-1, pH of 3, and operating temperature of 50 ºC. Adsorption of Cr(VI) by the prepared activated carbon was spontaneous and followed second-order kinetics. The adsorption mechanism can be described by the Freundlich Isotherm model. The prepared activated carbon has demonstrated comparable performance to other available activated carbons for the adsorption of Cr(VI).

  • Researchpp 1519-1538Vandenbossche, V., Doumeng, C., and Rigal, L. (2014). "Thermomechanical and thermo-mechano-chemical pretreatment of wheat straw using a twin-screw extruder," BioRes. 9(1), 1519-1538.AbstractArticlePDF

    Different thermo-mechanical extrusion pretreatments were evaluated as alternatives to traditional biomass pretreatments for lignocellulosic ethanol production. Wheat straw, a commonly available agricultural co-product, was chosen as the substrate model for the study. Five thermo-mechanical pretreatments were evaluated: one purely thermo-mechanical (TM) using just water, and the rest thermo-mechano-chemical (TMC), thus using acid, alkaline, oxidant in alkaline medium, and organic solvent. The parietal constituents, hemicelluloses, cellulose, and lignin were quantified to enable the amounts extracted by the pretreatment to be estimated. The digestibility of cellulose was evaluated by quantifying the hydrolysability with an enzyme cocktail. Water thermomechanical treatment gave strong straw defibration; however the digestibility only attained 35%, whereas ground wheat straw was already 22%. This improvement is insufficient to prepare material for direct enzymatic hydrolysis; thus a combination of the thermo-mechanical and chemical treatment is required. All chemical treatments produced greater improvements in cellulose digestibility. For the acidic treatments, hydrolysability was between 42 and 50%, and reached 89% with alkaline pretreatment.

  • Researchpp 1539-1551Turku, I., Nikolaeva, M., and Kärki, T. (2014). "The effect of fire retardants on the flammability, mechanical properties, and wettability of co-extruded PP-based wood-plastic composites," BioRes. 9(1), 1539-1551.AbstractArticlePDF

    In this work, fire retardants (FRs) such as aluminum trihydroxide (ATH), zinc borate (ZB), melamine, graphite, and titanium oxide (TiO2) were loaded into the shell layer of a co-extruded polypropylene (PP)-based wood-plastic composite (WPC). The incorporated retardants reduced the peak of the heat release rate by 8 to 22%, depending on the type of FR. Other studied parameters, such as ignition time and mass loss rate, were improved after the FR loading. The total heat release decreased slightly (except for the graphite-WPC). The effective heat of combustion was independent of the presence of the FR or, in the case of graphite, slightly increased. Carbon monoxide production increased (ZB, graphite) or was not changed significantly (ATH, melamine, and TiO2). It was also observed that the tensile strength improved after the FR loading; however, the tensile modulus decreased, except for the graphite-WPC. The impact strength improved or was independent of the FR loading, as in the case of the sample with ATH. The wettability of the composites decreased with filler loading, except for ZB, which showed the highest water absorption value among the studied composites.

  • Researchpp 1552-1564Lee, K. M., Ngoh, G. C., Chua, A. S. M., Yoon, L. W., Ang, T. N., and Lee, M.-G. (2014). "Comparison study of different ionic liquid pretreatments in maximizing total reducing sugars recovery," BioRes. 9(1), 1552-1564.AbstractArticlePDF

    A process scheme combining the most suitable ionic liquid pretreatment, followed by solid acid and enzymatic saccharification was used to maximize the reducing sugars recovery from sago waste. Three types of ionic liquids, i.e. 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]) and 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM][(EtO)2PO2]) were evaluated based on their performance in terms of the total reducing sugars recovery, chemical cost, and pretreatment energy requirement. The results showed that all the ionic liquids assisted the saccharification processes by dissolving and depolymerizing the carbohydrates of the sago waste into shorter chain soluble oligosaccharides, as well as disrupting the biomass structure to produce an amorphous pretreated solid residue. The solid acid saccharifications of the prehydrolysates obtained from the [BMIM]Cl pretreatment gave the highest reducing sugars recovery (61-63%) irrespective of the solid acid catalyst employed. On the other hand, enzymatic saccharification of [EMIM][OAc] pretreated solid residues showed the highest reducing sugars recovery (29%). A maximum recovery of 90% reducing sugars was achieved via incorporation of the ionic liquid pretreatment, solid acid and enzymatic saccharifications using [BMIM]Cl, Amberlyst 15 (A15) and Trichoderma viride cellulase respectively. This study suggests that the combined sequential process can maximize the reducing sugars recovery from sago waste effectively.


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