NC State
  • Editorialpp 8116-8118Hubbe, M. A. (2016). "My production facility, my laboratory of discovery," BioRes. 11(4), 8116-8118.AbstractArticlePDF

    By exercising of one’s curiosity, in combination with a lot of persistence, it is possible to solve some seemingly intractable problems. Many readers of this journal will have spent much, if not all of their careers, in university laboratories. In such settings there is an understandable emphasis on understanding underlying reasons. In other words, one is expected to focus on “why things happen” rather than just getting results. But if such an approach works well at the university, how about applying it at the production facility? This editorial features the stories of a man who was brave enough to spend his career asking “why” questions while working to improve the operations of paper mills.

  • Editorialpp 8119-8122Zhang, A., and Shen, J. (2016). "Adding growth-promoting ingredients in activated sludge process as a troubleshooting strategy for pulp and paper mill wastewater treatment," BioRes. 11(4), 8119-8122.AbstractArticlePDF
    The activated sludge process is a well-established technology in the secondary treatment of pulp and paper mill wastewater. Maintaining the activities of microorganisms and allowing them to thrive, metabolize, and grow robustly is essential for efficient biological reactions. To this end, a scientific formulation of growth-promoting ingredients (containing stimulants, buffers, micronutrients, etc) provides a useful strategy for addressing the impact of fluctuations in process conditions involved in the pulp and paper production. Lots of potential exists in terms of the use of these “smart” ingredients to meet stricter discharge limits.
  • Researchpp 8123-8138Balea, A., Blanco, Á., Concepción Monte, M., Merayo, N., and Negro, C. (2016). "Effect of bleached eucalyptus and pine cellulose nanofibers on the physico-mechanical properties of cartonboard," BioRes.11(4), 8123-8138.AbstractArticlePDF
    Extending the limits of paper recycling by increasing the number of recycling cycles results in decreased mechanical properties due to the irreversible hornification of cellulose fibers. This process alters the fiber structure and properties because of the repeated chemical and mechanical treatments that occur during wetting and drying. As a result, poor tensile strength is the main source of customer complaints to paper manufacturers. Cellulose nanofibers (CNF) from bleached eucalyptus and pine pulps were investigated as potential strength additives because of their proven contribution to interfiber bonding. These results were compared to the results obtained using different families of strength additives. The effects on the mechanical properties of recycled old corrugated containers were studied by measuring bursting, tensile, and short span compressive strength. Cellulose nanofibers and cationic polyacrylamide (cPAM) improved the mechanical strength properties when they were added at doses around 4 wt.%. A combination of CNF and cPAM was also tested. The effects of the combined additives were not as high as expected compared to the results achieved individually. The CNF from pine pulp resulted in the highest increase in bursting index when combined with cPAM, achieving an increase of over 93%. The combination of CNF from eucalyptus pulp and cPAM increased the bursting index over 60%.
  • Researchpp 8139-8154Pereira-Ferraz, G., Frear, C., Pelaez-Samaniego, M. R., Englund, K., and Garcia-Perez , M. (2016). "Hot water extraction of anaerobic digested dairy fiber for wood plastic composite manufacturing," BioRes.11(4), 8139-8154.AbstractArticlePDF
    Dairy farmers worldwide are facing the difficulty of managing or disposing of dairy manure. Anaerobic digestion (AD) is an option for treating dairy manure and producing biogas. A byproduct of AD is fiber, which is only partially being used despite its potential for different products, including wood plastic composites (WPCs). However, some properties of WPCs need to be improved to use them in high moisture content environments. This work evaluates the effect of hot water extraction (HWE) (at 160 °C for 60 min) of the AD dairy fiber on properties of WPCs. WPCs were produced using AD fiber via extrusion and tested for mechanical properties and water affinity. The WPCs produced with HWE fiber exhibited increased mechanical strength (36%) and stiffness (30%), and reduced strain at break (15%) compared to composites produced with untreated fiber. Water sorption and thickness swelling were reduced by 39% and 36%, respectively, after immersion in water for 98 days. The diffusion constant of WPCs produced with HWE fiber was also reduced by 64%. These results show that HWE is an effective method for enhancing mechanical properties and reducing hydrophilicity of WPCs produced from AD fiber.
  • Researchpp 8155-8165Luján-Rhenals , D. E., and Morawicki, R. O. (2016). "Production of fermentable sugars and a high protein meal by dilute acid hydrolysis of soybean meal at high temperatures," BioRes. 11(4), 8155-8165.AbstractArticlePDF
    The objective was to produce fermentable sugars with low levels of fermentation inhibitors and a high-protein meal, with acceptable color, by treating defatted soybean meal with dilute sulphuric acid at temperatures between 105 and 135 oC and durations up to 45 min. The conditions that maximized the amount of protein were 120 °C, 0.5% H2SO4, and 45 min, which increased protein from 48.1% to 58.6% d.b. The highest amount of fermentable sugars (32.2% d.b.), without regard for the protein content, was for the treatment at 135 °C, 2% H2SO4, and 45 min; such treatment generated relatively low 5-HMF and furfural levels (0.0018 g/L and 0.32 g/L, respectively), and 0.87 g/L, of acetic acid. The treatment at 120 °C, 1.5% H2SO4, and 30 min had the best balance between a high concentration of fermentable sugars (21.3% d.b.) in the liquid fraction and crude protein (52.1% d.b.) in the solid fraction without a significant change in the original color of the solid fraction.
  • Researchpp 8166-8177Gu, R., Mu, B., and Yang, Y. (2016). "Bond performance and structural characterization of polysaccharide wood adhesive made from konjac glucomannan/chitosan/polyvinyl alcohol," BioRes. 11(4), 8166-8177.AbstractArticlePDF

    The bond performance and bonding mechanism were evaluated for a Konjac glucomannan (KGM), Chitosan (CS), and polyvinyl alcohol (PVOH) blended wood adhesive. An optimized experimental strategy was used to investigate the effects of the formula parameters of adhesives on the bonding strength of plywood using a Box-Behnken design and response surface methodology (RSM). The microstructure of the blended adhesives was analyzed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). An optimum bonding strength (3.42 ± 0.31 MPa) was achieved with concentrations of KGM, CS, and 10% PVOH of 2.3%, 2.3%, and 5.0%, respectively. There was strong hydrogen bonding between the KGM, CS, and 10% PVOH adhesives and the interface. SEM observations indicated that the blended adhesive exhibited a net-like structure that increased the overall bonding strength. These results provided the scientific basis for the continual development of environmentally friendly wood adhesives and the improvement of processing conditions.

  • Researchpp 8178-8199Boran, S., Kiziltas, A., Kiziltas, E. E., and Gardner, D. J. (2016). "Characterization of ultrafine cellulose-filled high-density polyethylene composites prepared using different compounding methods," BioRes.11(4), 8178-8199.AbstractArticlePDF

    An extensional flow mixture (EFM) system was studied, with the goal of achieving better distributive and dispersive mixing. The effects of different mixing strategies (masterbatch method (MB), polyethylene-grafted maleic anhydride (PE-g-MA) as a compatibilizer, and compounding devices, such as a single screw extruder (SSE), a twin screw extruder (TSE), and an extensional flow mixer (EFM)) on the mechanical, thermal, rheological, and morphological properties of ultrafine cellulose (UFC)-filled high-density polyethylene (HDPE) composites were investigated. Maximum tensile strength (17.7 MPa), tensile modulus (0.88 GPa), flexural strength (18.8 MPa), and flexural modulus (0.63 GPa) were obtained from the MB compounding method. The maximum stress-strain (13.8%) was obtained with EFM compounding. Polymer composites from SSE and SSE/EFM compounding methods with PE-g-MA exhibited slightly higher crystallinity compared with other compounding methods. The storage modulus of the samples prepared with the MB method was higher than those prepared with the SSE compounding method. The UFC-filled HDPE composites from the EFM compounding process exhibited lower melt viscosities than the other composites at high shear rates. Scanning electron microscopy (SEM) images showed the cellulose to be distributed and dispersed reasonably well in the HDPE matrix when using a coupling agent in combination with the MB and EFM compounding methods.

  • Researchpp 8200-8214Verdet, M., Salenikovich, A., Cointe, A., Coureau, J. L., Galimard, P., Toro, W. M., Blanchet, P., and Delisee, C. (2016). "Mechanical performance of polyurethane and epoxy adhesives in connections with glued-in rods at elevated temperatures," BioRes. 11(4), 8200-8214.AbstractArticlePDF

    Glued-in rods have successfully been used for connections or reinforcement of timber structures due to their high strength and stiffness. However, their performance is potentially sensitive to temperature. This paper deals with an experimental investigation of the connections and adhesives in elevated temperatures. First, dynamic mechanical analysis (DMA) tests were performed to characterize an epoxy (EPX) and a polyurethane (PUR) adhesive. The evolution of the stiffness and the glass transition temperature, Tg, were measured in the range of 30 °C to 120 °C. Then, a total of 66 specimens with glued-in rods and the same adhesives were tested under a static tensile load at 20 °C, 40 °C, 50 °C, 60 °C, and 70 °C. In both types of tests, the EPX outperformed PUR due to its higher stiffness at temperatures of up to 40 °C; however, it showed a more rapid degradation of the stiffness and strength than the PUR at higher temperatures. No direct correlation was established between the Tg and the performance of the connections. The test results suggest that timber structures with glued-in rods may be vulnerable in service at temperatures above 40 °C.

  • Researchpp 8215-8225Yang, C., Zhu, X., Kim, N. H., Lee, S. H., Qi, Y., Bai, Y., Guo, M., and Ma, Y. (2016). "Experimental design and study of micro-nano wood fiber processed by nanosecond pulse laser," BioRes. 11(4), 8215-8225.AbstractArticlePDF

    A new processing technology using a nanosecond pulse laser to process micro-nano wood fiber is proposed in this paper. A test bench was designed and manufactured for the technology. The digital design process, experimental methods, and general layout principle of the test bench are introduced. When the factors that affected the results of the experiment were analyzed, it was found that cutting width and cutting depth were affected by cutting direction, cutting speed, and cutting power. The wood underwent thermal degradation near the point of processing. The results of the experiment showed that the technology is feasible.

  • Researchpp 8226-8238Zheng, S., Song, K., Zhao, J., and Dong, C. (2016). "Inverse estimation of effective moisture diffusivity in lumber during drying using genetic algorithms," BioRes. 11(4), 8226-8238.AbstractArticlePDF

    This article presents a methodology based on genetic algorithms (GA) optimization with a three-dimensional numerical solution to the diffusion model obtained by using the finite volume method (FVM) for determining the effective moisture diffusivity in lumber. The objective or error function between measured and simulated drying curves was obtained, and the effective moisture diffusivity parameters with greatest correspondence between measured and estimated values were obtained. As a result, a new equation for effective moisture diffusivity was proposed, which depends on lumber moisture content and drying temperature. Effective moisture diffusivities ranged from 1.120 × 10-9 to 1.277 × 10-8 m2/s. Finally, the proposed coefficients were validated by experiments. The drying kinetics were successfully simulated with the optimized effective moisture diffusivity model.