Volume 9 Issue 3

The current discussions of indirect land use change (iLUC) and the greenhouse gas (GHG) reduction potential of bioresources have turned into a rather controversial debate. The scientific robustness and consistency of current iLUC models and data are at least unclear. However, representatives of the scientific community still dare to provide straightforward political advice in their papers – way beyond the fact-based ‘proof’ of their data and on a level that is usually not accepted by scientific journals. But the actual task and challenge for the scientific community is to determine the environmental performance of bioresources as objectively and fact-based as possible – with a clear and sober focus on integrity and soundness, not sense of mission.

Currently, about 20 universities in China offer undergraduate courses related to pulp and paper. This large number is congruent with the rapid development of the Chinese pulp and paper industry in the past several decades. In the context of ever-increasing internationalization and global cooperation, English-assisted teaching in Chinese universities has much potential. The wide-spread implementation of English-assisted teaching would promote the career development of students and help foster the advancement of the Chinese pulp and paper industry.

Readers of this journal may be keenly aware of cellulose’s remarkable attributes, such as high stiffness, insolubility in just about everything, resistance to enzymatic attack, dimensional stability in the lengthwise direction, and toughness associated with the alternating crystalline zones and less organized regions. But if you dissolve cellulose and then allow it to recrystallize, the resulting crystals are at the same time radically different, and yet remarkably similar in most respects to the native form. Exactly half of the macromolecules in regenerated cellulose have been reversed 180 degrees in their direction. The behavior of dropped pencils can help explain why this happens.

In 2008, the European Union Commission put forward a proposal for a new directive on renewable forms of energy. Each of the member states should increase its share of renewable energies in an effort to boost the total share of the EU from the current 8.5% to 20% by 2020. The level of renewable energy in Finland was 28.5% in 2005, and the national target share of renewable energy by 2020 is 38%. To assist in reaching this goal, one solution is to further develop drying techniques of biomasses and utilization of untapped biomasses, because in Finland, up to 20 million tons of waste wood biomass per year are left unused during forestry operations. In this study the drying of biomasses and the condensate, including biodegradation of organic pollutants, is examined. The cost-efficiency and energy-efficiency of wood chips combustion can be increased by drying the wood to optimize moisture content before being utilized in different applications. However, the removal of moisture is the most expensive unit process in combustion. Studied wood species were pine (Pinus sylvestris), spruce (Picea abies), aspen (Populus tremula) and two birch species (Betula pendula and Betula pubescens). The biodegradation degrees of studied organic pollutants in condensing waters were between 25% and 61%. Furthermore, the biodegradation of organic compounds in condensing waters showed that at least the studied condensates can be safely disposed via municipal wastewater treatment plant (WWTP).

Computational Fluid Dynamic (CFD) modeling applications of the biomass gasification process help to optimize the gasifier. This study aims to investigate the impact of several physical parameters on the behavior of gasification in a fixed-bed downdraft gasifier. To that end, the study presents a comparison of the results computed using the Fire Dynamics Simulator (FDS) model with experimental results of biomass gasification. Therefore, different sets of simulations and experiments have been performed to examine the effects of initial moisture content, equivalence ratio, high heating value (HHV), and cold gas efficiency (CGE). At the optimum operation, the equivalence rate is 0.3, the HHV can reach 5.71 MJ/m3, and the produced hydrogen concentration is 26.53 vol%. For an initial moisture content of 11.18%, the measured CGE is 66.85%, which is within the range of 65.07% to 70.44%. In general, the initial moisture content of the rice husks is suggested to be below 18%. The overall results indicate that the FDS model can effectively simulate and analyze gasification performance inside the gasifier, and the performance of an improved downdraft gasifier system (IDGS) is improved by higher cold gas efficiency.

The effect of sharpness angle on tool wear and the effect of tool wear on machined surface roughness were investigated in wood flour/polyethylene composite (WFPEC) peripheral up-milling using cemented tungsten carbide (TC) tools. It was shown that nose width and edge recession increased with increasing feeding length. During the milling process, the wear of the nose width was smallest for the tool with a sharpness angle of 45°, followed by tools with sharpness angles of 55° and 65°. The wear of edge recession was highest for the tool with a sharpness angle of 45°, followed by tools with sharpness angles of 55° and 65°. The nose width increased with increasing sharpness angle, the edge recession decreased with increasing sharpness angle, and the machined surface roughness increased with increasing sharpness angle after a feeding length of 40 m. The nose width had a positive effect on the machined surface roughness, and the machined surface roughness increased with increasing nose width. The edge recession had little effect on the machined surface roughness. The clearance face roughness of the worn tool increased with increasing sharpness angle. The analysis of the SEM micrographs and EDS of the clearance face of the worn tool showed that the wear mechanisms of the cemented tungsten carbide tool were oxidation and abrasion in the range tested during cutting. Thus, a slight wear of the edge recession is gained in exchange for a lower machined surface roughness by decreasing the sharpness angle.

In this work, sustainable and biodegradable Acacia nilotica leaf (AN) was chemically modified to remove Cu(II) from aqueous solutions, which is considered a versatile approach to clean contaminated aquatic environments. Zinc chloride-modified Acacia nilotica leaf (ZAN) was characterized by scanning electron microscopy (SEM) and other physico-chemical parameters like pHZPC. The aim was to assess the efficiency and mechanism of adsorption on Acacia nilotica via isotherm models (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Harkin-Jura, and Frenkel-Halsey-Hill), kinetic models, and thermodynamic parameters. To optimize the removal efficiency, parameters such as effect of initial concentration, effect of pH, dosage, initial concentration, and contact time were studied by batch and column methods. Desorption studies illustrated that about 73% of the metal ions could be removed using 0.2N HCl. The results of the present investigation indicated that ZAN has a high potential for the removal of Cu(II) from aqueous solutions, and the resultant data can serve as a base line for designing treatment plants on an industrial scale.

Alkyl levulinates have been identified as promising chemicals with various industrial applications. Here, a catalytic process for the synthesis in an n-butanol medium of n-butyl levulinate via the alcoholysis of biomass-derived furfuryl alcohol was performed using an extremely low concentration of sulfuric acid (≤ 0.01 M) as the catalyst. A study was conducted that was designed to optimize the process variables, which include acid concentration, reaction temperature, initial substrate concentration, and water content, as a function of time. The optimum conditions resulted in a furfuryl alcohol conversion of nearly 100% and a high n-butyl levulinate yield of up to 97%, which was confirmed by isolated yield. An advantage of this catalyst system is that negligible undesired oligomeric products were formed from the side reaction for the polymerization of furfuryl alcohol, the catalyst cost is low, and less solid waste was discharged from the neutralization of spent acid. Overall, this catalytic strategy is a facile, efficient, and economical approach to the conversion of biomass-derived furfuryl alcohol into alkyl levulinates.

The composition of methylated fatty acids from wood, bark, and leaves of Brachychiton diversifolius was analyzed for the first time using gas chromatography (GC). The results indicated that the major methyl ester of fatty acids found in wood, bark, and leaves were: myristic acid (8.32%), palmitic acid (15.66%), and palmitic acid (9.95%), respectively. In accordance to the biological effects of fatty acid fraction, they were moderately effective against Bacillus subtilis and Sarcina lutea, but they did not show any effect against the growth of Staphylococcus aureus and Pectobacterium carotovorum at a concentration of 2000 μg/mL. The maximum percentages of inhibition of fungal mycelial growth against Penicillium selerotigenum (60.35%), Paecilomyces variotii (70.80%), and Aspergillus niger (70.50%) were shown by the fatty acids from leaves, bark, and bark, respectively. The total antioxidant activity (TAA %) of fatty acids from wood, bark, and leaves, were 40±3.13%, 80±5.14%, and 60±4.50%, respectively. In accordance to the results, the different parts of B. diversifolius could provide important components, such as fatty acids with antimicrobial and antioxidant activities for future studies or uses.

This study used thermo-mechanical densification technology to compress low-moisture content (3~5%) rapid-growth Populus tomentosa var. tomentosa trees to produce specimens with a low-compression ratio (small volume loss) and a uniform density profile and desirable properties. Furthermore, the densified specimens were subjected to post-heat treatment at 180, 190, and 200 °C for 2, 3, and 4 h, respectively. Microscopic examination was performed to observe the changes that occurred in the wood vessels after densification. To determine the influence of post-heat treatment on the set recovery, the specimens were subjected to eight cycles of soaking and drying in 20 °C water and two cycles in boiling water. The density profile tendencies of the densified specimens were in accord with undensified specimens. Microscopic observation revealed that the deformations present in the densified wood resulted from the viscous buckling of cell walls without fracture. The volume of the void areas in the specimens decreased uniformly. Post-heat treatment can decrease compressive deformation, especially when applied at 200 °C for 4 h. After two boiling water cycles of soaking and drying, the densified wood still had a certain set recovery. Therefore, densified wood should be used sparingly in high temperature and high humidity environments.