Research Articles

The effects of steamed Populus deltoides fiber were studied relative to the physical, mechanical, and morphological characteristics of composites made from virgin polypropylene. Fibers of Populus deltoides were used during the reinforcement phase at 180 °C for 1 h. The tests were carried out with 57% of virgin polypropylene that was combined with 3% of maleic anhydride-modified polypropylene and 40% of wood fiber. The wood fiber portion consisted of either non-steamed fiber, steamed fiber, and an equal mixture of the two kinds of fiber. Mixing was done using an internal mixer at 180 °C and 60 rpm, and the standard samples were constructed by injection molding. Then, the physical and mechanical characteristics of samples were measured. To consider compatibility between the matrix and reinforcement phase, SEM pictures were taken from the break surface of composite samples. The results showed that the composites’ strengths were affected by steam, as components having steamed fibers had the best mechanical strength and dimensional stability, and also the least water absorption and thickness swelling.

Marine environments are unique habitats for microorganisms and represent uninvestigated areas that possess valuable resources. Fungi may also be important because they contribute to marine ecosystems as decomposers. The aims of this study were to investigate the halo-tolerance of marine-derived fungi and their enzymatic properties. Eighteen fungal strains representing 11 different species were used, which included 17 ascomycetes and a zygomycete. The majority were not affected by salinity and showed endo-glucanase (EG) and β-glucosidase (BGL) activities. Interestingly, the cellulolytic enzyme activity derived from Penicillium chrysogenum FU42 increased with salinity. To investigate whether this increase was due to an adaptation or an innate ability of the species, P. chrysogenum KCTC6933, which originated from a terrestrial environment, was used as a control, and its enzymatic properties were compared. Consequently, P. chrysogenum FU42, which was derived from the ocean, showed unique enzymatic properties that might enable the fungus to live in the ocean and contribute to the nutrient cycle in marine ecosystems.

The influence of selected factors, such as wood species, veneer combinations, and loading cycles, on the bending strength and modulus of elasticity of glued laminated wood was investigated after cyclic loading of 0, 1000, 3000, and 7000 cycles with European beech (Fagus sylvatica (L.)) and Eurasian aspen (Populus tremula (L.)) The laminated woods were created by a combination of densified and non-densified veneers. The 30% densification was carried out by cold rolling. All factors and their interactions had statistically significant influence on the modulus of elasticity. Similarly, the influence of all factors on bending strength was statistically significant. However, the mutual interaction of all factors had no significant effect.

Microspheres were generated after subjecting corn stem rind to high-pressure water pretreatment. These microspheres can be divided into two categories according to their location: free microspheres and adsorbed microspheres. The formation and characterization of both microsphere types were studied. For the free microspheres, the maximum formation was reached at 180 °C; when the temperature was too high (200 °C) or too low (120 °C), no free microspheres were observed. As pretreatment temperature was varied, the morphologies of the free microspheres were different. For the adsorbed microspheres, their formation occurred over a wider temperature range, and their density increased with rising pretreatment temperature. Using Fourier transform infrared spectroscopy, many C=C and C=O bonds were identified on the surface of the free microspheres, indicating the presence of functional groups similar to those of lignin. Compared with untreated corn stem rind, the lignin signal of the residue surface was enhanced, which may be attributable to the increase in adsorbed microsphere quantity.

In this work, volatile organic compounds (VOCs) in the ambient air of a secondary fiber paper mill were analyzed. For the sake of studying pollution comprehensively, four sites in the paper mill were analyzed and active sampling methods were used. Desorption was carried out with two solvents, carbon disulfide and dichloromethane. The compositions of VOCs were determined by gas chromatography-mass spectrometry (GC-MS) method. The main identified substances in the four sites were as follows: (1) waste paper sorting room: alkanes, phenols, and esters; (2) papermaking workshop: benzene series, alkanes, ethers, and phenols; (3) vacuum pump outlet: benzene series and phenols; and (4) office area: benzene series and phenols. Two main toxic substances in VOCs, the benzene series and phenols, were detected in the ambient air of the paper mill. The benzene series existed in three places along the main process of the paper mill and even existed in the office area, which was far away from the production line. Additionally, phenols were detected in all sampling locations in the paper mill.

The effect of immobilized yeast on bioethanol production before and after adding laser-pretreated corn stalk residue were investigated. Response surface methodology was used to optimize the conditions of adding residue. An optimum experimental condition was obtained at pH 4.5, 2.08% yeast concentration, and 0.20% corn stalk residue. Under these conditions, adding residue increased the yield of bioethanol from 53.2% to 86.5%, which matched the predicted value. The yield was relatively stable within 28 d, with a downward trend subsequently appearing.

The feasibility of using near-infrared spectroscopy (NIR) to identify wood species was investigated in this study. Case I considers the principal component analysis scores plot of NIR spectra for three wood species. Case II considers whether NIR combined with partial least squares discriminant analyses can be used to identify the three wood species. Three wood species were studied, and each species included five randomly collected wood blocks, 21 samples for each wood block, and 315 total wood samples. In case I, the samples in the PCA analysis were clustered together. In case II, samples in the training set were classified into the correct group, and the accuracy of the test set was up to 90%.

Nanoscale porosity is critical for cellulose reactivity and can be detrimentally affected by wet pressing. The present study evaluated how wet pressing reduced the nanoscale porosity of a set of pulps produced from sugarcane bagasse. The pulps were produced using hydrothermal treatments, followed by either 160 °C alkaline (sodium hydroxide) or 190 °C organosolv (ethanol-water) pulping. Pulping times (20, 40, 60, 80, and 100 min) and applied pressures in the pressing step (21, 43, 64, 85, and 107 MPa) were varied, and the resulting samples had their nanoscale porosity characterized using calorimetric thermoporometry. The lowest applied pressure (21 MPa) collapsed a considerable fraction of the nanoscale porosities. Otherwise, when additional pressure (up to 107 MPa) was applied, a much lower reduction in porosity was observed. The findings indicate that nanoscale porosity of pulps can be separated into compressible and incompressible components.

This article deals with cutting power during the plane milling of thermally treated and untreated silver birch (Betula pendula Roth.) wood. Thermal treatment was carried out at various temperatures of 160, 180, 210, and 240 °C. The cutting power was measured under various milling conditions, such as rake angle of tool (10°, 15°, 20°, 25°, and 30°), cutting speed (20, 40, and 60 m/s), and feed speed (4, 8, and 11 m/min). Thermal treatment had no clear impact on the cutting power. Treated wood at 160 and 180 °C had lower values of cutting power in comparison with untreated wood, while the opposite trend was observed at 210 and 240 °C. The results show that with increasing speed feed, there is an increase in cutting power, while the opposite effect was achieved by changing the cutting speed. The optimum values of cutting power were achieved at a 10° angle and a thermal treatment of 160 °C.

Biomass yield was studied for tall wheatgrass, tall fescue, tall oatgrass, and Miscanthus ´ giganteus per hectare of cultivation, as well as their calorific value and cost of cultivating these biomasses. Chemical analyses were performed on these raw materials to determine their lignin, cellulose, extractives, and ash contents. The analytical results are compared to the chemical constituents found in birch and pine wood. It was found that the grasses examined in this study differed in biomass yield and cost to cultivate (1 ha plot). Tall wheatgrass, tall fescue, tall oatgrass, and Miscanthus leaves had lower levels of lignin compared with wood, but also lower amounts of cellulose. When determining the cellulose content of these biomasses, the amount of inorganic ash that is bound to them must be taken into account.