NC State
  • Researchpp 6766-6777Dumitrascu, A., Salca, E., Mihail, L., Ciobanu, V., and Musat, E. (2018). "Inferential statistics of Quercus species in veneer cutting," BioRes. 13(3), 6766-6777.AbstractArticlePDF

    Quercus species represent 18% of the total forest area in Romania, of which 2% refers to common oak and 10.5% refers to sessile oak. These species are of special importance for Romanian silviculture due to their value in multiple industrial uses. The finest and most efficient use of valuable timber is wood veneer. This paper presents a comparative analysis of the efficiency in veneer cutting for two Quercus species, common oak and sessile oak, originating from the Snagov area in Romania. The statistical parameters of veneer efficiency were estimated with high accuracy by using the least squares method with a 95% normal confidence interval based on the Anderson-Darling test and the correlation coefficient. The analysis of inferential statistics used the estimation of the 87th percentile, determining the cumulative density functions for the species under study. More defects were found in common oak logs than in sessile oak logs, which produced more veneer sheets. The veneer efficiency for sessile oak logs was superior to that of common oak logs. These findings might have practical applications in industrial conditions when screening for the best log species with high efficiency in veneer cutting.

  • Researchpp 6778-6789Premjet, S., Dana, S., Obeng, A., and Premjet, D. (2018). "Enzymatic response to structural and chemical transformations in Hibiscus sabdariffa var. altissima bark and core during phosphoric acid pretreatment," BioRes. 13(3), 6778-6789.AbstractArticlePDF

    To investigate the potential of Hibiscus sabdariffa var. altissima (Thai kenaf) biomass as a feedstock for bioethanol production, Thai kenaf bark and core were pretreated at a moderate temperature with different phosphoric acid (H3PO4) concentrations. It was revealed that there was a higher glucan content in the Thai kenaf bark (57.97% ± 0.36%) compared with that in the core (43.10% ± 0.15%). The H3PO4 pretreatment resulted in a reduction in the lignin content and total removal of hemicellulose. This exposed the cellulose to attack by cellulase enzymes and resulted in an increased enzymatic digestibility. A high glucose concentration (GC; 7.02 g/L) and hydrolysis efficiency (HE; 95.79%) were achieved with 75% H3PO4 for the bark after 72 h of enzymatic hydrolysis. However, these values were not that different from those of the 70% H3PO4-pretreated bark (6.89 g/L and 95.43%, respectively). Nevertheless, the Thai kenaf core pretreated with 75% H3PO4 recorded a higher GC (6.30 g/L) and HE (91.67%) after 72 h of enzymatic hydrolysis. The scanning electron microscopy and X-ray diffraction analyses revealed the destruction of the surface structure and an increase in the porosity and crystallinity index of the Thai kenaf biomass, which corresponded to an increased enzymatic digestibility.

  • Researchpp 6790-6801Liu, F., Xue, Y., Liu, J., Gan, L., and Long, M. (2018). "ACE3 as a master transcriptional factor regulates cellulase and xylanase production in Trichoderma orientalis EU7-22," BioRes. 13(3), 6790-6801.AbstractArticlePDF

    As an efficient fungus in secreting cellulase, Trichoderma orientalis EU7-22 has an important value in the degradation of biomass. Compared with other filamentous fungi, it has an important, unique nature, and it deserves intensive study. Therefore, the function of positive transcriptional regulator ACE3 was investigated for cellulase and hemicellulase production in the strain. As the ace3 knockout strain, the Δace3 mutant was constructed by homologous recombination, so that the enzyme activities (FPA, CMC, CBH, BG, XYN) and the extracellular protein concentration in the mutant strain decreased to 17.8%, 8.3%, 0.14%, 1.8%, 6.8%, and 19.2% of the parent strain, respectively. The transcription level of cellulase and hemicellulase genes also decreased significantly. The result of SDS-PAGE demonstrated that the Δace3 mutant only clearly showed a protein band, which was characterized by protein profiling with LC-MS/MS and identified as the GH10 family of xylanases. It was proposed that ACE3 is a main up-regulation transcriptional factor of T. orientalis EU7-22 and expected to be applicable to further genetic modification.

  • Researchpp 6802-6817Park, C., Youe, W., Namgung, H., Han, S., Seo, P., Chae, H., and Lee, S. (2018). "Effect of lignocellulose nanofibril and polymeric methylene diphenyl diisocyanate addition on plasticized lignin/polycaprolactone composites," BioRes. 13(3), 6802-6817.AbstractArticlePDF

    Kraft lignin was plasticized with ε-caprolactone via twin-screw extrusion at 150 °C, and its glass transition temperature was decreased from 155 to 96 °C. The lignin or plasticized lignin (p-lignin)/polycaprolactone (PCL) composites with and without lignocellulose nanofibril (LCNF) or polymeric methylene diphenyl diisocyanate (pMDI) were prepared, and their properties were compared. The p-lignin was better dispersed in the PCL than neat lignin, and the p-lignin/PCL composites exhibited a homogenous fractured surface despite the addition of LCNF. An increase in the lignin or p-lignin content decreased the tensile strength and elastic moduli but increased the melt flow index (MFI). With the addition of pMDI and LCNF, the tensile properties and MFI improved and declined, respectively. The strength improvement by pMDI and LCNF was better in the p-lignin/PCL composite than in the lignin/PCL composite.

  • Researchpp 6818-6836Zhang, Y., Liu, Z., Hui, L., and Wang, H. (2018). "Diols as solvent media for liquefaction of corn stalk at ambient pressure," BioRes. 13(3), 6818-6836.AbstractArticlePDF

    The proper selection of solvents is important during liquefaction of biomass process to produce fuel additives and valuable chemicals. In this study, novel low-cost liquefying agents such 1,2-propanediol (PG), diethylene glycol (DEG), and 1,4-butanediol (BDO), as well as the traditional liquefying agent, ethylene glycol (EG), were used. It was found that the liquefaction yield of corn stalk in the presence of PG at the optimum temperature of 180 °C was up to 99.2%, which was higher than that of the other three liquefying agents. The main components and functional groups of bio-oil with an acid catalyst were characterized by gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR). The chief constituents of bio-oil were complex, and corn stalk could be effectively degraded with PG liquefaction. Moreover, the thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM) data also revealed that the fiber structure of the liquefied corn stalk was destroyed and essentially liquefied during PG liquefaction. Consequently, all the results in the study successfully confirmed that PG can provide an efficient and environmental process for generating bio-oil from lignocellulosic mass at a low cost in liquefaction of corn stalk.

  • Researchpp 6837-6849Wang, Q., Shen, J., Shen, X., and Du, J. (2018). "Volatile organic compounds and odor emissions from alkyd resin enamel-coated particleboard," BioRes. 13(3), 6837-6849.AbstractArticlePDF

    To solve the odor emission problem of lacquer veneer particleboards, as well as to identify the key odor compounds and their sources, alkyd resin enamel-coated particleboards were studied via gas chromatography-mass spectroscopy-olfactometry. A single-factor experiment was established under various environmental conditions. The odor-causing compounds were identified, and the effects of environmental factors on the volatile organic compounds (VOCs) and odor emissions were investigated. The results showed that the main odor substances released from the alkyd resin enamel-coated particleboard were aromatic compounds, aldehydes, and alkanes, which are typically low in toxicity. The total volatile organic compounds concentration and total odor intensity increased as the temperature and relative humidity increased, but decreased as the air exchange rate to loading factor ratio increased. The temperature had a greater impact on the release of VOCs from the alkyd resin enamel-coated particleboard than either the relative humidity or air exchange rate to loading factor ratio. The odor substances concentration increased with an increase in the temperature, while the relative humidity and air exchange rate to loading factor ratio had little effect.

  • Researchpp 6850-6867Miao, Y., Qin, L., Liu, Z., Yang, L., and Lv, X. (2018). "Effects of furfurylation on acoustic vibration performance of Paulownia wood," BioRes. 13(3), 6850-6867.AbstractArticlePDF

    This study investigated the effects of furfurylation on the acoustic vibration performance of Paulownia wood on the basis of improving dimensional stability. Paulownia wood was chemically modified with 25%, 50%, and 75% furfuryl alcohol and different curing times (8 h, 12 h, and 15 h). The dimensional stability of Paulownia wood was significantly improved after furfuryl alcohol modification. As indicators of acoustic vibration efficiency, the acoustic impedance (ω,), attenuation coefficient (δ), and periodic energy loss (tanδ/E) parameters were improved. The vibration sound evaluation indicator E/G was also evaluated. The best treatment conditions were 25% furfuryl alcohol and an 8 h curing time. Under these process conditions, the acoustic impedance ω, attenuation coefficient δ, and periodic energy loss parameter tanδ/E of the Paulownia wood increased by 21.1%, 156%, and 157%, respectively, the E/G indicator increased by 38.8%, and the specific dynamic elastic modulus E/r and acoustic quality constant R decreased by 36% and 45%, respectively. The sound quality was reduced under other process conditions.

  • Researchpp 6868-6892de Assis, T., Reisinger, L., Dasmohapatra, S., Pawlak, J., Jameel, H., Pal, L., Kavalew, D., and Gonzalez, R. (2018). "Performance and sustainability vs. the shelf price of tissue paper kitchen towels," BioRes. 13(3), 6868-6892.AbstractArticlePDF

    This study aimed to identify the performance properties that drive the shelf price of kitchen paper towels and evaluate whether sustainability is an important driver for pricing. Nineteen products were compared according to their performance (softness, absorbency, and strength), technology, and fiber morphology. Metrics to rank the products in different grades (economy, premium, and ultra) according to their performance were provided. A multiple linear regression showed that absorbency and softness are the most significant properties used to predict the price. Market data indicates that there is a segment of consumers willing to pay a premium price for products marketed as “sustainable”, even though their performance is comparatively inferior to the majority of the samples. Sustainable products are up to 85% more expensive than regular products. The metrics obtained in this work can contribute to improvement in market transparency, and aid companies in deciding strategies for product development and new investments.

  • Researchpp 6893-6910Bernard, A., Gélinas, N., Duchateau, E., Durocher, C., and Achim, A. (2018). "American beech in value-added hardwood products: Assessing consumer preferences," BioRes. 13(3), 6893-6910.AbstractArticlePDF

    The depleted state of the northern hardwood forests of Quebec, Canada has forced the hardwood flooring industry to adapt its production. American beech (Fagus grandifolia), a traditionally less desired species, is now increasingly being included in wood supplies to sawmills in western Quebec, where forest managers hope this resource can be valued before the onset of significant mortality and wood degradation from the beech bark disease. This study aimed: 1) to assess the preferences of consumers towards American beech flooring products compared to well known species traditionally used in this market; and 2) to compare results obtained in face-to-face surveys with web-based surveys of consumer preferences. Results from both survey types revealed that the finishing colour was the most important factor affecting the decision of respondents, followed by species and price. American beech ranked third in species preferences, just above birch. Divulgating species names only affected (positively) the perception of respondents towards oak. It was concluded that American beech could be included in the current wood flooring market, probably among cheaper options such as birch. The similarity of results from face-to-face and online surveys suggests that general trends in consumer preferences could be rapidly and cheaply assessed using the latter option.

  • Researchpp 6911-6921Marçal, A., França, L., and Corrêa, N. (2018). "Hydrothermal treatment of empty fruit bunch (EFB) aimed at increased production of reducing sugars," BioRes. 13(3), 6911-6921.AbstractArticlePDF

    The waste generated from the palm oil production chain is increasing. The purpose of this work is to enable more effective use of empty fruit bunches (EFB) to produce reducing sugars by a hydrothermal treatment process (hydrothermolysis) at elevated pressures and temperatures. The EFB was dried and milled to obtain three different granulometries: thin (> 60 mesh), medium (28 to 60 mesh), and thick (< 28 mesh). The operating conditions were defined using a complete factorial design of 25, while considering the variables as particle size (thin, medium, and thick), solid/liquid ratio (1/13.33 and 1/20), temperature (130 and 170 ºC), reactor pressure using CO2 (150 bar and 200 bar), and reaction time (10 and 20 min). The reactional system converted the EFB into 17.5% and 57.9% of reducing sugars, for thin and medium samples, respectively, which were performed under the same conditions. The statistical analysis indicated that the main effects for hydrothermal treatment are time and temperature.