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BioResources, Volume 4, Issue 4
NOTE: Each current issue of BioResources continues to build as new articles are approved.
The forest products industry in North America is increasingly losing its share in its domestic markets. The pressure of low cost manufacturing combined with a slowing economy has painfully caused many mills to close and many workers to lose their jobs in recent years. We ask ourselves whether the forest products industry will be able to survive these gloomy times and what, if any are the factors that would drive the future of the forest products industry. Opening our minds to global markets beyond domestic consumption, targeting products towards changing demographic structure and resulting change in consumer tastes, developing and marketing products with the environmental conscious consumer in mind, product innovations, efficient management of the supply chain, and trade practices and policies will be some of the marketing drivers in the forest products industry in the new era. PDF
The effects of several non-ionic commercial surfactants and their dosage on soda pulping and ECF bleaching of soda and soda-surfactant pulps of bagasse were investigated. The properties of bleachable pulps obtained with conventional soda and with soda-surfactants were studied and compared. The results showed application of surfactants during the soda pulping of bagasse decreased kappa number and improved the yield and brightness of resulting pulp. Using the surfactants reduced alkali consumption during pulping. The bleaching experiments showed that the pulps obtained with the three types of applied surfactants namely, ELA-2, FAE-20, and PEG1000 could be easily bleached with D0ED1 or D0EpD1 sequences. The addition of most used surfactants in soda pulping of bagasse led to higher brightness in comparison to reference pulp with the same bleaching sequence. Strength properties of bleached pulps obtained with surfactants were higher than the pulp obtained with conventional soda pulping. PDF
Telysheva, G., Dizhbite, T., Jashina, L., Andersone, A., Volperts, A., Ponomarenko, J., and Mironova-Ulmane, N. (2009). "Synthesis of lignin-based inorganic/organic hybrid materials favorable for detoxification of ecosystem components," BioRes. 4(4), 1276-1284.
Combination of lignin matrices (including those modified with silicon oligomers or quaternary ammonium compounds) and such inorganic building blocks as copper and manganese cations (Cu2+, Mn2+) made it possible to synthesize novel hybrid organic-inorganic materials. The synthesized hybrid materials were characterized with significantly increased (2-9 times) values of specific surface area in comparison with those for non-modified and Si-modified precursor matrices. The Cu2+-containing hybrid materials differed by enhanced sorption capacity towards proteins and bacteria. PDF
Chemical modification of hardwood sawdust from ash-tree species was carried out with a solution of maleic anhydride in acetone. Wood polymers, lignin, and cellulose were isolated from the wood sawdust and modified by the same method. Samples were characterized by Fourier transform infrared spectroscopy (FTIR), providing evidence that maleic anhydride esterifies the free hydroxyl groups of the wood polymer components. Composites comprising chemically modified wood sawdust and wood polymers (cellulose, lignin)-as variable weight percentages-, and poly (vinyl chloride) were obtained and further characterized by using FTIR spectroscopy and scanning electron microscopy (SEM). The thermal behavior of composites was investigated by using the thermogravimetric analysis (TGA). In all cases, thermal properties were affected by fillers addition. PDF
Haron, M. J., Tiansih, M., Ibrahim, N. A., Kassim, A., and Wan Yunus, W. M. Z. (2009). "Sorption of Cu(II) by poly(hydroxamic acid) chelating exchanger prepared from poly(methyl acrylate) grafted oil palm empty fruit bunch (OPEFB)," BioRes. 4(4), 1305-1318.
This paper describes the preparation of chemically modified oil palm empty fruit bunch (OPEFB) with hydroxamic acid functional group and its use for the sorption of Cu(II) from aqueous solution. OPEFB was grafted with poly(methylacrylate) (PMA), using H2O2/Fe2+ as initiator. The PMA grafted OPEFB (PMA-OPEFB) was treated with hydroxylammonium chloride in alkaline medium to produce hydroxamic acid grafted fiber (PHA-OPEFB). The FTIR spectrum of OPEFB grafted with PMA showed an intense absorption band at 1734 cm-1 which is attributed to C=O vibration in the grafted ester. After hydroxylamine treatment, the intensity of absorption band at 1734 cm-1 decreased and new bands appeared at the 1640 cm-1 related to C=O vibration in hydroxamic acid and at the 1568 cm-1 related to the N-H amide. Sorption of Cu(II) by PHA-OPEFB was effective over a pH range of 4 to 6. The sorption followed the Langmuir model with maximum capacities of 74.1 mg g-1 at 25 °C. The sorption process was exothermic, as shown by the negative value of enthalpy change, DH°. The free energy change (DG°) for the sorption was negative, showing that the sorption process was spontaneous. A kinetic study showed that the Cu(II) sorption followed a second order kinetic model. PDF
Bio-oil produced from fast pyrolysis of biomass contains various levels of acetic and formic acids derived from breakdown of cellulose and hemi-cellulose components. Removal of these organic acids from bio-oil was investigated for use as industrial chemicals as well as to improve the quality of recovered bio-oil as fuel in various applications. Calcium oxide and a quaternary ammonium anion-exchange resin were used to form acid salts of the organic acids, which were then separated, and the organic acids were generated by reacting with sulfuric acid. Both methods were found to be effective in limited ways and various difficulties encountered in this approach are discussed. PDF
This study concerns the implementation and performance evaluation of fibrous composites in sterile filtration of wine. Conditions of preparation were established having in view that the separation of particulate contaminants from liquids by depth filtration is occurring by mechanical entrapment into structural pores and by electrokinetic adsorption, and both retention mechanisms are influenced by various factors. Functional characteristics and behaviour of the filtering composite in industrial filtration of wine were evaluated. It was found that the effectiveness with which micro-organisms were retained was substantially improved by a porous structure characterized by small pores, and respectively by high resistance to air filtration, as well as by a higher content of cationic charges in the system. PDF
Pirraglia, A., Saloni, D., and van Dyk, H. (2009). "Status of lean manufacturing implementation on secondary wood industries including residential, cabinet, millwork, and panel markets," BioRes. 4(4), 1341-1358.
Lean Manufacturing has helped several industries to achieve operational and manufacturing excellence by increasing productivity and enhancing quality, while reducing waste and costs. However, the wood industry has been historically slow in adopting this philosophy and its many tools. In times when overseas competition has taken big portions of the traditional market share for U.S based wood industries, it has become important that companies start to take actions in order to regain competitiveness. In this sense, Lean Manufacturing could provide a competitive advantage. Main findings of this project includes high percentages of Lean Manufacturing implementation among companies from the Wood Component Manufacturing Association, substantial differences in the tools implemented by companies on an early vs. extensive Lean Manufacturing implementation stage, as well as identification of main reasons and advantages derived from its implementation, and how Lean Manufacturing is rated among these companies. Findings lead to the conclusions that many companies are pursuing cost savings strategies without implementing Lean Manufacturing. Training and education on Lean Manufacturing, and well implemented Lean Manufacturing programs would help members of the Wood Component Manufacturing Association to regain competitiveness and achieve substantial cost reductions. PDF
Cotton linters were hydrolyzed with different concentrations of HCl (2.5-15%) to prepare microcrystalline cellulose. Infrared spectroscopy and thermal analysis were used to follow the effect of hydrolysis on the molecular structure of the produced microcrystalline cellulose. The loss in weight and the degree of polymerization of the produced hydrolyzed cotton linters were determined. Scanning electron microscope images and x-ray diffraction were also studied for more information about the crystallinity, fiber length, particle size, and shape of the produced microcrystalline cellulose. Water retention value and water absorption were estimated for the hydrolyzed cotton linters to explain the effect of hydrolysis on the amorphous and crystalline part of the hydrolyzed cotton linters. The obtained results showed that the crystallinity index of the hydrolyzed cotton increased by increasing acid concentration and then began to decrease at 15% HCl. Kinetic energy (calculated from thermogravimetric curves) of the hydrolyzed cellulose was higher than that of the untreated cotton linters, and at high acid concentration this activation energy began to decrease. PDF
Quintero, O. L., Amicarelli, A. A., Scaglia, G., and di Sciascio, F. (2009). "Control based on numerical methods and recursive Bayesian estimation in a continuous alcoholic fermentation process," BioRes. 4(4), 1372-1395.
Biotechnological processes represent a challenge in the control field, due to their high nonlinearity. In particular, continuous alcoholic fermentation from Zymomonas mobilis (Z.m) presents a significant challenge. This bioprocess has high ethanol performance, but it exhibits an oscillatory behavior in process variables due to the influence of inhibition dynamics (rate of ethanol concentration) over biomass, substrate, and product concentrations. In this work a new solution for control of biotechnological variables in the fermentation process is proposed, based on numerical methods and linear algebra. In addition, an improvement to a previously reported state estimator, based on particle filtering techniques, is used in the control loop. The feasibility estimator and its performance are demonstrated in the proposed control loop. This methodology makes it possible to develop a controller design through the use of dynamic analysis with a tested biomass estimator in Z.m and without the use of complex calculations. PDF
The incorporation of crop residues was studied in particleboard panels (agrifibers, AG) in mixture with wood from Pinus radiata D. Don. Four crop residue stubble types were used, wheat, corn, rice plants, and rice husk. Their densities were compared. A wide array of mixtures varying from 9:1 = wood:AG to 1:9 = AG:wood were used to make the boards, from which the fundamental physical and mechanical properties were determined, to select one with the best properties and use potential. All AG were suited for board panels, although wheat and corn stubble gave better results, and their low fibre content was easily incorporated in low proportions without major modifications of processes and products. PDF
Conventional bleaching of hardwood CMP pulp with magnesium hydroxide (Mg(OH)2) show significant benefits over bleaching with sodium hydroxide (NaOH) under various conditions. Magnesium hydroxide bleaching generate higher optical properties, higher pulp yield and lower effluent COD at the same chemical charge, but the physical properties were found to be similar for both processes. The initial freeness of the bleached pulps and refining value to reach a target freeness (about 350 ml. CSF) were more for the Mg(OH)2-based process. The residual peroxide of filtrate from the Mg(OH)2-based process was very high as compared to conventional bleaching. PDF
Erakhrumen, A. A., and Ogunsanwo, O. Y. (2009). "Water absorption, anti-swell efficiency, and dimensional stability properties of neem seed-oil treated wild grown Bambusa vulgaris Schard. ex J. C. Wendl. in southwest Nigeria,"BioRes. 4(4), 1417-1429.
Bamboo culm is a hygroscopic lignocellulosic material. Hygroscopic properties may be disadvantageous in bamboo material if applied in certain applications and modes where and when extreme moisture variations are likely to occur. This study was aimed at evaluating the moisture absorption and resistance including dimensional stability properties of neem seed oil-treated split bamboo samples using two methods of treatment. Split bamboo samples from the same source were oven-dried at 103±2oC, conditioned to 11.76% mean moisture content, and treated by completely soaking them in oil at room temperature for 24 hours and by soaking in hot oil at 60oC for 4 hours, with untreated samples as control. Results showed that samples soaked in hot oil at 60oC for 4 hours had both the least percentage water absorption and higher anti-swell efficiency, followed by samples soaked in oil at room temperature for 24 hours. Shrinkage in the longitudinal, radial, and tangential directions also followed the same trend. Conclusions and recommendations were made in line with the outcome of the study. PDF
A strength grading process, starting with log grading, was studied with respect to grading yield, impact on quality, and economic efficiency when visual grades according to Nordic grading rules were used for alternate product comparison. Pine (Pinus sylvestris) and spruce (Picea abies) logs and boards were graded with several varieties of commercial grading and strength-grading equipment. The boards were destructively tested, and the European grade-determining properties strength, stiffness, and density were measured. Models for these were made by partial least squares and validated. A method for the derivation of settings for multiple indicating properties, which increased yield in some cases, was proposed and evaluated. Grading to grade combinations of C40, C30, and C18 was done. The impact of visual override based on deformations was also studied. A simplified economic and sensitivity analysis was done. The outcome was that log grading can be used for strength grading with good economic and quality results. Strength pregrading on logs improves sawmill economy, depending on the species and market situation. Drying quality greatly influences the yield through visual override grading on deformations. Market prices of high grades (>C30) must improve in order to stimulate supply, as it is more economical to produce lower grades. PDF
Natural fibres are partly replacing currently used synthetic fibres as reinforcement for polymer composites. Jute fibre bundles were high-cellulose-content modified by alkali treatment, while the bagasse fibre bundles were modified by creating quinones in the lignin portions of fibre surfaces and reacting them with furfuryl alcohol (FA) to increase their adhesiveness. The effects of different fibre bundle loading and modification of bagasse fibre surfaces in hybrid fibre reinforced epoxy composites have been studied. The role of fibre/matrix interactions in chemically modified hybrid composites were investigated using Differential Scanning Calorimeter, Differential Thermo Gravimetry, and a Universal Tensile Machine and compared with those of unmodified bagasse fibre bundles incorporated with modified jute fibre bundles reinforced hybrid composites. Fibre surface modification reduced the hydrophilicity of fibre bundles, and significantly increased mechanical properties of hybrid composites were observed in conjunction with SEM images. The SEM analysis of the fibre and the composite fractured surfaces have confirmed the FA grafting and shown a better compatibility at the interface between chemically modified fibre bundles and epoxy resin. This paper incorporates interesting results of thermomechanical properties and evaluation of fibre/matrix interactions. PDF
Wang, J., Chen, Y., Wang, X., and Cao, F. (2009). "Aluminum dodecatungstophosphate (Al0.9H0.3PW12O40) nanotube as a solid acid catalyst one-pot production of biodiesel from waste cooking oil," BioRes. 4(4), 1477-1486.
Solid nanocatalyst aluminum dodecatungstophosphate (Al0.9H0.3PW12O40, abbreviated as AlPW) with nanotube structure was synthesized through a natural cellulose fiber template. The AlPW nanotubes, which are highly water-tolerant and acid-tolerant, can be described as green double acids, as they combineboth Brønsted and Lewis acid sites. They have been applied as an efficient nanoheterogeneous catalyst for the preparation of biodiesel from waste cooking oil containing 26.89 wt% high free fatty acids (FFAs) and 1% moisture via esterification of FFAs and transesterification of triglycerides in one pot under mild conditions. PDF
Rice straw (Oryza sativa L.) pulp was treated by high intensity ultrasonication to make fibrils. The rice straw fibril (RSF) material was used as reinforcement in an RSF/polypropylene (PP) composite. The influences of RSF and coupling agent (MAPP) contents on tensile properties of the composite were tested. The results showed that when RSF loading was 5%, the tensile strength rose to a maximum value of 31.7 MPa. With increasing fibril loading the tensile modulus increased first, then decreased. However, the elongation at break decreased with increasing fibril loading. There was no significant influence of MAPP content on tensile strength and elongation at break of PP and RSF/PP composite. When MAPP content was 4%, the tensile modulus of PP and RSF/PP composite all showed maximum values. PDF
Shen, J., Song, Z., Qian, X., and Liu, W. (2009). "Modification of precipitated calcium carbonate filler using sodium silicate/zinc chloride based modifiers to improve acid-resistance and use of the modified filler in papermaking," BioRes. 4(4), 1498-1519.
In order to improve the acid-resistant property of papermaking grade precipitated calcium carbonate filler and to obtain modified filler in powder form, sodium silicate/zinc chloride based modifiers were used in filler modification, and the use of modified filler in papermaking of deinked pulp derived from recycled newspaper was also preliminarily investigated. Under the preliminarily optimized experimental conditions, when sodium silicate, zinc chloride, sodium hexametaphosphate, and phosphoric acid with dosages of 10 wt%, 3 wt%, 1 wt% and 0.2 wt%, respectively, were used as modifiers, and when the temperature, aging time, and PCC concentration during the filler modification process was 70 oC, 7 h and 9.1 wt%, respectively, the acid-resistant property of filler was significantly improved after modification, as evaluated using alum consumption and pH methods. The use of modified precipitated calcium carbonate filler prepared under the optimized conditions provided considerably more brightness and light scattering improvement in comparison to unmodified filler, and filler modification was found to have only negligible influence on tensile and burst strength of the paper, air permeability of the paper, and retention performance of the filler. Surface analysis of the modified filler using XPS and SEM confirmed the occurring of surface encapsulation and modification of precipitated calcium carbonate filler when the relevant modifiers were used in filler modification. The encapsulating effect of modifiers on filler was thought to be favorable to improvement in acid-resistant property, and optical properties of the filled paper. PDF
The objective of this study was to develop a supported tri-metallic catalyst (nano-Ni-La-Fe/γ-Al2O3) for tar removal in biomass steam gasification, to significantly enhance the quality of the produced gas. For this purpose, the supported tri-metallic catalysts were prepared by a deposition-precipitation (DP) method. Different analytical approaches were used to characterize the synthesized catalysts. The results showed that the prepared tri-metallic catalysts had an egg-shell structure with a specific surface area of 214.7 m2/g. The activity of the catalysts for gas production and tar removal in the process of biomass gasification was also investigated using a bench-scale combined fixed bed reactor. The experiments indicated that the tar yield after adding catalyst was reduced significantly and the efficiency of tar removal reached 99% for the biomass steam gasification at 800oC, while the gas yield after adding catalysts increased markedly and less coke was found over the catalyst. Meanwhile, the compositions of gas products before and after adding catalyst in the process also changed significantly; in particular, the content of hydrogen in catalytic steam gasification was improved by over 10 vol%. Therefore, using the prepared tri-metallic catalyst in biomass gasification can significantly improve the quality of the produced gas and efficiently eliminate the tar generation, preventing coke deposition on the catalyst surfaces, thus demonstrating a long lifetime of the catalyst. PDF
Ayrilmis, N., Dundar, T., Candan, Z., and Akbulut, T. (2009). "Wettability of fire retardant treated laminated veneer lumber (LVL) manufactured from veneers dried at different temperatures," BioRes. 4(4), 1536-1544.
Wettability of the fire retardant treated (FRT) laminated veneer lumber (LVL) manufactured from wood veneers dried at different temperatures was investigated. Commercially manufactured veneer of beech wood (Fagus orientalis L.) was treated with borax-boric acid (BX/BA, 1:1 by weight), monoammonium phosphate (MAP), and diammonium phosphate (DAP) using a full-cell pressure process. The veneers were then dried at different temperatures (120, 140, 160, and 180°C), and experimental LVLs were made from these veneer sheets. The wettability of LVL was characterized by contact angle analysis. The lowest contact angle was obtained from LVL made from BX/BA-treated veneers, while the highest value was found for the control LVL. The CA values of these samples at each re-drying level were lower than LVLs made from untreated veneers. Re-drying of the treated veneers decreased the CA values of the LVL, while it was found higher for the LVL made from untreated veneer. PDF
Sahin Kol, H., Özbay, G., and Altun, S. (2009). "Shear strength of heat-treated tali (Erythrophleum ivornese) and iroko (Chlorophora excelsa) woods, bonded with various adhesives," BioRes. 4(4), 1545-1554.
The aim of this study was to evaluate the effect of heat treatment on the shear strength of tali (Erythrophleum ivorense) and iroko (Chlorophora excelsa) woods, bonded with some structural adhesives. Shear strength of untreated and heat-treated woods bonded with phenol-formaldehyde (PF), melamine-urea-formaldehyde (MUF), melamine-formaldehyde (MF), and polyurethane (PUR) adhesives was studied. An industrial heat treatment method (ThermoWood) was used. The timbers were thermally modified for 2 hours at 180 ºC. Laminated samples having two sample sets were prepared from untreated and heat-treated wood for the shear strength test. The results of the tests showed that the heat treatment affected shear strength of laminated wood negatively. Although there was a considerable difference in adhesive bond shear strength between untreated and treated wood, both wood species bonded with the adhesives fulfilled the required value for shear strength of the adhesive bonds. PF, MUF, MF, and PUR adhesives performed in a rather similar way for both wood species. PDF
Pulp and paper mills are large energy consumers which can often achieve economic savings by implementing energy-saving measures. The process unit with the greatest energy demand in a mill is usually the evaporation plant. If excess heat can be made available in the mill, and the heat can be used in the evaporation plant, significant energy-savings can be achieved. In this paper, this kind of energy-efficient evaporation is called process-integrated (PI) evaporation, and the paper investigates the techno-economic consequences of PI evaporation. Theoretical plants with 6–8 evaporation effects are simulated using an in-house simulation tool called OptiVap. Conventional plants are used as reference, and evaporation plants with either lower surface condenser temperature or extraction of lignin are included. The results show that the additional profit of PI evaporation plants is 0.3–1.5 €/ADt in comparison with conventional plants. By lowering the temperature of the surface condenser, the profit is raised by 0.6–0.9 €/ADt for both conventional and PI plants. With lignin extraction, the PI plants are 0.7–1.7 €/ADt more profitable than the conventional ones. PDF
Bleached unrefined and refined sawdust kraft pulps were added to bleached Norway spruce thermomechanical (TMP) and pressurised groundwood (PWG) pulps in different proportions. Handsheets were prepared and tested for physical properties. In addition, economic calculations were done to estimate the production costs of different bleached pulps in Finland. It was found that the addition of unrefined and refined sawdust kraft pulp improved drainability of the mechanical pulps. Tear strength of PGW furnishes was increased when either unrefined or refined sawdust pulp was added. Tear strength of TMP furnishes was not influenced when different sawdust kraft pulps were added. Up to 30 % of unrefined sawdust kraft pulp could be added and no significant negative effect was observed in TMP and PGW furnishes. On the other hand, when refined sawdust kraft pulp was added into the mechanical pulp furnishes, a clear improvement in the tensile strength was observed. According to the economic calculation the production cost of bleached sawdust kraft pulp is almost as low as the production cost of bleached mechanical pulp. We suggest that economically viable sawdust kraft pulp can be used as a substituent for expensive long fibre reinforcement kraft pulp in the production of mechanical pulp based papers. PDF
Ouyang, J., Li, Z., Li, X., Ying, H., and Yong, Q. (2009). "Enhanced enzymatic conversion and glucose production via two-step enzymatic hydrolysis of corncob residue from xylo-oligosaccharides producer's waste," BioRes. 4(4), 1586-1599.
A study was conducted to investigate the hydrolysis of cellulose-enriched corncob residue, a cellulosic waste from the xylo-oligosaccharides industry, by two processes. The corncob residue was hydrolyzed by cellulases via direct hydrolysis and two-step hydrolysis. Cellulases were produced by Trichoderma reesei RutC-30 with kraft pulp as the substrate. When the cellulase dosage was above 8 FPU•g-1 of corncob residue and the corncob residue concentration was 3%, over 90% hydrolysis yield and 49.99% glucose yield were obtained at 48 h. To enhance the hydrolysis yield of corncob residue, a new process coupling enzymatic hydrolysis, separation, and acid treatment was investigated. The corncob residue was first hydrolyzed using cellulase for 24 h. Then the remaining solids of corncob residue was separated from the liquid containing soluble oligosaccharides, and allowed to subsequently hydrolyze, using the adsorbed enzyme for 24 h. Using this method, the total hydrolysis yield was up to 97.60%, which represents an increase by 7.5% in comparison to the direct 48 h enzymatic hydrolysis. When the hydrolysates of the two-step enzymatic process were subjected to the concentrated acid hydrolysis at 110 ºC for 2 h, the glucose yield could be increased from 43% to 90%. PDF
Reflectance UV-Vis spectroscopy and UV resonance Raman (UVRR) spectroscopy are both nondestructive techniques that are applicable to study trace concentrations of lignin in-situ. In this study, unbleached and bleached softwood kraft pulps were analyzed by reflectance UV-Vis (k/s) and UVRR spectroscopy to follow lignin and hexenuronic acid (HexA) contents and structural changes in residual lignin. The height of the lignin band in the UV-Vis spectra (280 nm) correlated well with the lignin band in the UVRR spectra (1605 cm-1) for semi- or fully-bleached pulps. However, the correlation was much weaker for unbleached pulps. Also the results for hexenuronic acid content by UV-Vis (240 nm) and UVRR (1658 cm-1) methods correlated well for most of the pulps, but for unbleached or peroxide-bleached samples the interference from other structures affecting these bands was obvious. PDF
Some scientific contributions have used near infrared (NIR) spectroscopy as a rapid and reliable tool for characterizing engineered wood products. However, to our knowledge, there are no published papers that used this technique in order to evaluate wood-cement panels. The main objective of this paper was to evaluate the ability of NIR spectroscopy to estimate physical and mechanical properties in wood-cement panels. The wood-cement panels were produced using Eucalyptus grandis x E. urophylla, Pinus taeda, and Toona ciliata woods with Portland cement under different manufacturing conditions. Wood-cement panels were characterized by traditional methods, and Partial Least Squares regressions were used to build calibrations. Our cross-validated models for MOR, IB, and TS24h of the panels yielded good coefficients of determination (0.80, 0.82, and 0.91, respectively). Based on the significant absorption bands and regression coefficients of the PLS models, our results indicate that cellulose and aromatic groups in lignin are components that play an important role in the calibrations. PDF
In-situ precipitation of calcium carbonate in bagasse fibers resulted in a very significant increase in specific scattering coefficient and consequently large improvements in opacity and brightness of the handsheets made from such pulp. At the same level of filler loading, the scattering coefficient of in-situ precipitated pulp was much greater than for directly loaded pulp. In-situ precipitation of calcium carbonate caused a drop in strength properties of bagasse pulp, but such loss could be recovered to a large extent by blending with other pulps. The effect of in-situ precipitation of calcium carbonate on pulp fibers was quite different for bagasse pulp from hardwood pulp. In-situ precipitation of calcium carbonate on hardwood fibers showed neither much improvement in optical properties nor much reduction in strength properties. PDF
The pH dependent adsorption behavior of chitosan onto a cellulose model surface was studied by quartz crystal microbalance with dissipation (QCM-D). The molecular level interactions between adsorbed chitosan layers were studied by atom force microscopy (AFM) colloidal probe force measurements in the liquid phase. Adsorption of chitosan increased with pH below the solubility limit of the polymer. The adsorption behavior could not be accounted for solely on the basis of electrostatic interactions; thus a specific interaction between the polymers existed. Swelling and viscoelastic properties of the adsorbed chitosan layer were strongly influenced by pH. At high pH, the layer deswelled and became more elastic due to insolubility of the chitosan. The colloidal probe force measurements showed a rise of electrosteric repulsion after adsorption of chitosan at pH 5. Above the solubility limit of the chitosan, at pH 7, the pull-off force and its range clearly increased compared to lower pH values, indicating that the wet adhesion between chitosan-coated cellulose surfaces increased. The presented results are discussed in relation to the ability of chitosan to improve the initial wet strength of paper. PDF
In this paper, the thermal conductivity and dielectric parameters for pine [Pinus sylvestris (L.)] woods were determined in transverse directions for moisture conditions from oven-dry to 22 percent at a room temperature of 22 to 24 °C. Results indicate that the behaviors of thermal conductivity and dielectric parameters with moisture content and structural directions were similar. In general, the properties increased within the range studied with increasing moisture content. The radial values were similar to tangential values for both thermal conductivity and dielectric properties. The data presented here should be useful in most design problems where pine wood is subjected to microwave electric fields and heat changes. PDF
Adsul, M. G., Terwadkar, A. P., Varma, A. J., and Gokhale, D. V. (2009). "Cellulases from Penicillium janthinellum mutants: Solid-state production and their stability in ionic liquids," BioRes. 4(4), 1670-1681.
The cellulase production by P. janthinellum mutants on lignocellulosic material such as cellulose or steam exploded bagasse (SEB) in combination with wheat bran was studied in solid state fermentation (SSF). One of the mutants, EU2D21, produced the highest levels of endoglucanase (3710 IU g-1 carbon source) and β-glucosidase (155 IU g-1 carbon source). Ionic liquids are so-called green solvents that have become attractive for biocatalysis. Stability of mutant cellulases was tested in 10-50% of the ionic liquid 1-butyl-3-methylimidazolium chloride ([bmim]Cl). FPA and CMCase were significantly stable in 10% ionic liquid after 5h. β-glucosidase showed 85% of its original activity after 5 h incubation in 30% ionic liquid and retained 55% of its activity after 24 h. This enzyme preparation hydrolyzed ionic-liquid-treated SEB completely in 15 h in the presence of 20% ionic liquid. These studies revealed that there is no need of regenerating cellulose after ionic liquid treatment, since cellulase of mutant strain was found to be significantly stable in the ionic liquid. PDF
Kurt, Ş., Uysal, B., Özcan, C., and Yildirim, M. N. (2009). "The effects of edge banding thickness of uludag fir bonded with some adhesives on withdrawal strengths of beech dowel pins in composite materials," BioRes. 4(4), 1682-1693.
Composite materials and wooden dowels are being used increasingly in the construction of furniture frames and inner decoration. Yet there is little information available concerning the withdrawal strength of various fasteners, and, in particular, dowels in composite materials edged solid wood edge bandings. The aim of this study was to determine the withdrawal strengths of 6, 8, 10 mm diameter dowels produced from beech with respect to edge of a medium-density fiberboard (MDF) or particleboard (PB) edged with 5, 10 and 15 mm thickness of solid wood edge banding of uludag fir, bonded with different adhesives. According to TS 4539 standard, the effects of edge banding thickness, dimension of dowels, type of composite materials and type of adhesives used for edge banding on the withdrawal strength were determined. The highest (6.37 N/mm²) withdrawal strength was obtained in beech dowels with 8 mm diameter for MDF with 5 mm thickness of solid wood edge banding of uludag fir bonded with D-VTKA adhesive. According to results, if the hole wall and the surface of dowel are smooth then the adhesives give better mechanical adhesion with dowels and composite materials. PDF
Laccases (benzenediol:oxygen oxidoreductase, EC 220.127.116.11) are multi-copper oxidases that are widely distributed among plants, insects, and fungi. They have been described in different genera of ascomycetes, some deuteromycetes, and mainly in basidiomycetes. These enzymes catalyze the one-electron oxidation of a wide variety of organic and inorganic substrates, including mono-, di-, and polyphenols, aminophenols, methoxyphenols, aromatic amines, and ascorbate, with the concomitant four electron reduction of oxygen to water. Laccase is currently the focus of much attention because of its diverse applications, such as delignification of lignocellulosics, crosslinking of polysaccha-rides, bioremediation applications, such as waste detoxification, and textile dye transformation, food technologic uses, personal and medical care applications, and biosensor and analytical applications. This review helps to understand the properties of this important enzyme for efficient utilization for its biotechnological and environmental applications. PDF
In the future liquid biofuels will need to be renewable, sustainable, as well as technically and economically viable. This paper provides an overview of the challenges that the biochemical production of cellulosic ethanol process still faces. The main emphasis of the paper is on challenges that emerge from the scale of liquid biofuel production. These challenges include raw material availability, other consumables, and side stream handling. The pretreatment, C5 fermentation, and concentration of sugars in processing need improvements, too. Sustainability issues and greenhouse gas reduction also pose a challenge for implementation and require development of internationally recognized sustainability principles and standards, and certification of sustainable operation. Economics of cellulosic ethanol processes are still also an area under development and debate. Yet, the Energy Independence and Security Act mandate together with the European Union Renewable Energy Directive and other local targets are driving the development and implementation forward towards more significant contribution of biofuels in the transportation sector. PDF
For over 2000 years the manual craft of papermaking has been practiced all over the world utilizing a variety of techniques. This review describes the evolution of hand papermaking and its cultural significance. Paper’s evolution has been shaped by the structure and chemical composition of the fibers. Almost every aspect of modern papermaking technology has been foreshadowed by traditional practices. Such practices were passed down for many generations within families of papermakers. The main sources of cellulosic fiber evolved as the ancient craft migrated from its birthplace in China to Korea and Japan, the Islamic world, and then to Europe and America. Though most paper made today comes from automated, continuous production systems, handmade paper has enjoyed a resurgence, both as a traditional craft and as an art-form. In addition, traditional papermaking methods can provide insights to help in modern applications involving cellulosic fibers. PDF