NC State
  • Editorialpp 295-296Hubbe, M. A. (2008). "Are lignocellulosic resources too valuable to burn?" BioRes. 3(2), 295-296.AbstractPDF
    Lignocellulosic matter often can be counted as a renewable resource, since it is produced by photosynthesis. But there are limits to how much biomass our society can use in a sustainable manner. People can debate whether or not it makes sense to use a substantial portion of lignocellulosic materials as a source of liquid fuel. This essay gives a qualified affirmative answer to the question in its title. However, combustion of lignocellulosic resources can be considered as wasteful and uneconomical, in the long run, if it is inefficient, if it fails to displace the combustion of fossil fuels, or if it displaces a higher-end use, for which there are available customers. In particular, it seems unlikely that combustion of fuels derived from lignocellulosic biomass can, by itself, solve problems that stem from society’s excessive thirst for motor fuels.
  • Researchpp 297-315Sun, Y., Lin, L., Deng, H., Li, J., He, B., Sun, R., and Ouyang, P. (2008). "Structural changes of bamboo cellulose in formic acid," BioRes. 3(2), 297-315.AbstractPDF
    The structure of cellulose from bamboo fiber before and after treatment in formic acid was investigated in comparison with microcrystalline-cellulose by solid state NMR, FTIR, and X-ray diffraction diagrams. Differences of molecular structures among two kinds of celluloses were validated and expatiated. Results from the experiments indicated notable differences in the crystalline or amorphous region of microcrystalline-cellulose and bamboo fiber. CP-MAS 13C-NMR, and FTIR spectroscopy revealed the presence of Iα and Iβ forms in all of the samples. The effect of acid solution was achieved simultaneously both in the crystalline region and the amorphous region, but there was a more intensive effect on the crystalline region for bamboo fiber. All of the cellulose samples revealed the same chain conformation but a different hydrogen bonding pattern. The absorbency of hydrogen bonds shifted to a high wave number and gradually decreased during treatment. The intermolecular hydrogen bond of 6-OH…O-3′ decreased first, and then increased gradually, which indicated that the cellulose bundled together during hydrolysis.
  • Researchpp 316-334Quintero, O. L., Amicarelli, A. A., di Sciascio, F., and Scaglia, G. (2008). "State estimation in alcoholic continuous fermentation of Zymomonas mobilis using recursive Bayesian filtering: A simulation approach," BioRes. 3(2), 316-334.AbstractPDF
    This work presents a state estimator for a continuous bioprocess. To this aim, the Non Linear Filtering theory based on the recursive application of Bayes rule and Monte Carlo techniques is used. Recursive Bayesian Filters Sampling Importance Resampling (SIR) is employed, including different kinds of resampling. Generally, bio-processes have strong non-linear and non-Gaussian characteristics, and this tool becomes attractive. The estimator behavior and performance are illustrated with the continuous process of alcoholic fermentation of Zymomonas mobilis. Not too many applications with this tool have been reported in the biotechnological area.
  • Researchpp 335-345Giese, E. C., Dekker, R. F. H., and Barbosa, A. M. (2008). "Orange bagasse as substrate for the production of pectinase and laccase by Botryosphaeria rhodina MAMB-05 in submerged and solid state fermentation," BioRes. 3(2), 335-345.AbstractPDF
    Orange bagasse comprising pulp tissues, rind, and seeds, constitutes a major industrial food waste arising from processing oranges for juice, and represents a fermentation feedstock for the production of enzymes. Botryosphaeria rhodina MAMB-05 grown on essential oils-extracted orange bagasse in submerged (SmF) and solid-state fermentation (SSF) with and without added nutrients produced pectinase and laccase. Highest enzyme titres (pectinase, 32 U ml-1; laccase, 46 U ml-1) occurred in SSF without added nutrients, indicating nutrient sufficiency of orange bagasse at a solids concentration of 16 % (w v-1) to sustain growth and high enzyme titres. Orange essential oil extract added to nutrient medium containing 1 % glucose in SmF strongly inhibited fungal growth with consequent lower laccase and pectinase activities. The results demonstrate the need to remove the essential oils fraction before citrus waste can be successfully used as a fermentation substrate for enzyme production.
  • Researchpp 346-362Deka, M., and Petrič, M. (2008). "Photo-degradation of water borne acrylic coated modified and non-modified wood during artificial light exposure," BioRes. 3(2), 346-362.AbstractPDF
    A series of experiments were carried out to investigate photo-degradation of thermally modified (at 210oC and minus 0.9 bars for two hours) and non-modified spruce wood [Picea abies L (Karst)], coated with transparent and semitransparent (with 3% pigment content) acrylic coatings during artificial UV light irradiation for 200 hours. Photo-degradation was evaluated in terms of colour changes throughout the irradiation period at an interval of 50 hours, along with IR and EPR spectroscopic study. One set of modified and non-modified woods was painted with coatings, while the other set was covered with free films made of coatings, just to simulate coated wood. The colour changes for both modified and non-modified wood samples without paint-coat or free film cover were comparable to that of wood samples with paint-coat and free film cover for transparent coat type, which indicated its ineffective-ness to prevent photo-degradation of wood underneath. However, the colour changes for both modified and non-modified wood samples with paint-coat and free film cover were much lower than those of samples without paint-coat or free film cover for semitransparent coat type, which might be due to hindrance of transmission of light energy through pigment to reach the underlying wood surface. On the other hand, whole substrate-coating system showed better photo-stability, when thermally modified wood was used as substrate. However, the colour changes of paint-coated and free-film covered samples for both modified and non modified woods might be due to colour changes of wood specimen underneath, because free films of both the coat types showed negligible colour change during UV irradiation.
  • Researchpp 363-382Xu, C., Su, H., and Cang, D. (2008). "Liquefaction of corn distillers dried grains with solubles (DDGS) in hot-compressed phenol," BioRes. 3(2), 363-382.AbstractPDF
    The present work aims to liquefy corn Distillers Dried Grains with Solubles (DDGS), a by-product in corn ethanol production, to produce liquid products as a potential substitute for petroleum-derived phenol or an additive in the manufacturing of phenolic resins. Efficient liquefaction of DDGS has been realized with hot-compressed phenol at 200-450°C. Effects of liquefaction temperature, initial phenol/DDGS ratio (wt/wt), residence time, and catalysts on yields of liquefaction products, as well as characterizations of typical liquid and solid products, have been investigated. The yield of liquid products increased with temperature, while it peaked at around 300°C, due to condensation/cracking reactions of the liquid intermediates/products to form solid products (i.e., coke/char) at temperatures higher than 300°C. The liquid yield increased monotonically with the initial phenol/DDGS ratio for a specified treatment time and temperature. An increased residence time generally produced a lower yield of liquid products, and a higher yield of solid residue, which was likely due to the increased coke/char formation from liquid products for a prolonged residence time. The yield of liquid products reached a maximum of 97 wt% at 300°C for 5 min-operation with Phenol/DDGS of 2/1. K2CO3, Rb2CO3, and NaOH were found very effective catalysts for enhancing the liquid yields. The use of these catalysts resulted in a 25% relative increase in the liquid yields for 5 minute operation with Phenol/DDGS of 1/1 at 300°C.
  • Researchpp 383-402Ekhtera, M. H., Rezayati Charani, P., Ramezani, O., and Azadfallah, M. (2008). "Effects of poly-aluminum chloride, starch, alum, and rosin on the rosin sizing, strength, and microscopic appearance of paper prepared from old corrugated container (OCC) pulp," BioRes. 3(2), 383-402.AbstractPDF
    The influence of rosin (0.1-0.3%), alum (0.4-0.6%), polyaluminum chloride (0.3-0.7%), and starch (0.5-1.5%) in the making of paper from old corrugated container (OCC) pulp on the freeness, breaking length, tear index, and burst index of pulp and paper sheets was studied. Using a full factorial design to identify the optimum operating conditions, equations relating the dependent variables to the operational variables of the chemical additives were derived that reproduced the former with errors lower than 5%. Using a high starch (1.5%), high PAC (0.7%), low alum (0.4%), and low rosin (0.1%) combination led to pulp that was sufficient to obtain paper with good strength properties (breaking length 5720m; burst index: 3.1 kPam2g-1; tear index: 6.2mNm2/g; Cobb test: 94; fold endurance: 1.52). SEM analysis showed increasing bonding between fibers together at this level of additives. The influence of starch on Cobb test values was not significant.
  • Researchpp 403-424El-Sharkawy, K., Haavisto, S., Koskenhely, K., and Paulapuro, H. (2008). "Effect of fiber flocculation and filling design on refiner loadability and refining characteristics," BioRes. 3(2), 403-424.AbstractPDF
    The loadability of a pulp refiner was studied using refiner data such as gap movement, total power, no-load power, and net refining power. Two different types of pulp and three different types of refiner filling were used in the study. The floc formation and floc size of each pulp was studied in a flow channel simulating filling grooves. The loadability of the pulp refiner was linked to refining effects such as fiber shortening, and internal and external fibrillation. The trapping point of the refiner, and therefore refiner loadability, was found to be more related to fiber characteristics such as fiber length and coarseness, while being less dependent on refining consistency in the range of 2.0-5.5%. The data on the formation of flocs and floc size was used to explain the trapping of fibers between refiner bars and the refiner gap width. Filling design characteristics such as groove width and cutting speed affect the gap width and trapping of flocs inside the refiner. Fillings with high cutting speed tend to break flocs composed of long and short fibers at the same rate and therefore both types of floc maintain the same gap width. On the other hand, wide-groove fillings with lower cutting speed have a gentler effect and the differences in fiber characteristics are easily reflected in the gap width and trapping point. Fillings with low cutting speed have a greater straightening effect than fiber cutting, whereas narrow-bar fillings have a more noticeable effect on fiber cutting, external fibrillation, and fiber swelling.
  • Researchpp 425-436Porankiewicz, B., and Wieloch, G. (2008). "Drill wear during the boring of particle board: A multi-factor analysis including effects of mineral contaminants," BioRes. 3(2), 425-436.AbstractPDF
    This paper evaluates and discusses multifactor non-linear, statistical dependencies of drill side-edges recession VBK and drill diameter recession delta DW on the cutting path length LC, the content of hard mineral contaminants CMC, the size of contaminant particles SMC, and the Mohs hardness MH. Significant influence of the cutting path LC, the content CMC of hard mineral contaminants (HMC), and the size of contaminant particles SMC was found, whereas the Mohs hardness MH of the contamination particles was less important.
  • Researchpp 437-451Brännström, M., Manninen, J., and Oja, J. (2008). "Predicting the strength of sawn wood by tracheid laser scattering," BioRes. 3(2), 437-451.AbstractPDF
    An industrial laser light scattering scanner, designed to detect the spiral grain angle of logs by the light scattering along the grain, was used on two large samples of Norway spruce (Picea abies (var. Karst)) in various sawn dimensions (approximately 750 pieces). Additional measurements were made by other techniques, such as X-ray scanning, resonance frequency measurement, and various manual measurements. The strength properties of the boards were measured by destructive testing in four-point bending according to European standard. Multivariate methods (PLS) were used to model the relationship between the bending strength of the board (MOR) and the measurements. Based only on the output from the simple tracheid scattering equipment, a model for MOR achieved an R² exceeding 0.3. Combinations with average density or outer shape parameters from log scanning resulted in R² 0.4 and 0.3 respectively, although these parameters alone only accounted for R² 0.2. The results can be used to increase the understanding of strength in wood and in an improved industrial strength-grading process.


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