Volume 18 Issue 2

The physical and mechanical properties of thermally modified wood impregnated with linseed oil were investigated to find the relationship between the treatment and the acoustic properties. The samples were impregnated with linseed oil (LO). Heat treatment was performed in an oven at four different temperatures, namely 160, 180, 210, and 240 °C. Statistically, the physical, mechanical, and acoustic properties of the treated wood were significantly intensified as compared to the control samples. The physical properties (water absorption) of the treated wood decreased by 72% as compared to the control group. However, while the increase in both MOR and MOE at 240 °C was 13%, the increase in CS at 240 °C was 7%. As a result of the heat treatment, the porosity increased by 33% as compared to the control group. At 240 °C the maximum SAC value was observed to be 0.71 at 5000 Hz and at 4500 Hz 0.78 and 0.80, respectively. The highest STL value, which was 69.9 dB, was observed at 1540 Hz and 3600 Hz. As a result of improved heat transfer, impregnating samples with LO before thermal modifications was observed to increase the efficiency of thermal modification.

The competitiveness of the laminated flooring industry was assessed in Iran. The statistical population was 200 persons, calculated using the stratified random method and the Cochran formula. The sample size was 132. After reviewing the literature, a conceptual model derived from the theoretical framework was presented. A researcher-made questionnaire was used to collect data. Content validity and confirmatory factor analysis were used to determine the validity of the questionnaire. Its reliability was calculated and confirmed using Cronbach’s alpha coefficient. The results were processed using structural equation modeling (SEM). The results showed a significant relationship between factors affecting perceived value, environmental and intra-organizational factors, and competitiveness in the laminated flooring industry. The evaluation of the quality of the model showed that the factors affecting the perceived value (strong effect = 0.632) and intra-organizational factors and environmental factors (moderate effect = 0.211 and 0.171) that were calculated, respectively, had the greatest effect on competitiveness. Moreover, these independent variables allocated 91.6% of competitiveness variations as the dependent variable.

The patterns and mechanisms underlying the effects of different types of biochar on crop dry matter accumulation and uptake of major soil minerals are uncertain. This study demonstrated the positive effects of adding pyrochar (PC) and hydrochar (HC) to calcareous soils on nutrient uptake by maize seedlings and revealed the important role of mycorrhizal colonization. The effects depended on the type of biochar added and the type of nutrient evaluated. The dry weights of maize seedlings were higher in the HC and PC groups than in the control group, and the P accumulation was 17% higher than that of the control. Adding PC significantly increased Zn accumulation and the concentration and accumulation of Cu in maize seedlings, whereas adding HC increased the Fe concentration. Applying PC and HC also promoted mycorrhizal colonization of maize roots, and P, Zn, and Cu accumulations in the plant were positively correlated with the mycorrhizal colonization rate. This study found that applying PC and HC to calcareous soil at the tested application rate promotes the uptake of some mineral nutrients by maize at the seedling stage, and this effect was at least partially influenced by an increased mycorrhizal colonization rate in the plant root system.

In order to contribute to the dissemination of lignocellulosic residues in the composite materials manufacturing, this study aimed to investigate the influence of a soaking in the presence of natural bacteria and fungi on the resistance to axial traction of açaí fibers (Euterpe oleracea Mart.). The stipulated factors and levels were the source of water, i.e., Rio Guamá, Pará Sanitation Company COSANPA and Cassava, as a catalyst and the mass concentration of water on the açaí cores, i.e., 2%, 4%, 6%. In this way, 9 different experimental conditions were performed, together with the reference condition, i.e., açaí fibers without the soaking. In all, 200 specimens were cast, with 10 of each composition. The analysis of variance results revealed that the individual factors were not significant in obtaining the axial tensile strength, providing equivalent results regardless of the concentration and type of water. However, the interaction between the factors was considered significant, showing that the best treatment for the fibers came from the use of 2% cassava scraps. The axial tensile strength was 47% greater than the axial tensile strength obtained from the reference sample. Furthermore, 59% surpassed the reference sample, showing the efficiency of the soaking in the presence of natural bacteria and fungi treatment.

Bioderived poly(lactic acid) (PLA) is a promising alternative for fossil-based polymers, but its poor hydrophilicity, high brittleness, and low heat-resistance are problems for its utilization. In this work, bleached softwood kraft pulp (BSKP) fiber was adopted to modify PLA with MAPP as the coupling agent, with BSKP accounting for 10 wt% to 50 wt%. Internal mixing (IM) was applied to mix the PLA/fiber blend instead of screw grinding. The thermal and mechanical properties of the composites were assessed. The IM process was proven qualified for its effective dispersion of BSKP fibers in the PLA matrix. At a fiber loading of 50 wt%, IM-processed composites acquired satisfactory tensile strength (50.49 MPa, slightly higher than PLA) and Young’s modulus (2.56 GPa, 45.8% higher than PLA). The pulp fillers matched PLA matrix well for the characteristic temperatures in thermal decomposition. The BSKP/PLA composites were thermally strengthened by pulp fibers characterized by higher content of residues. The fibers improved the interfacial crystallinity of PLA in the composites (i.e., from 5.22% to 11.86%). The increased crystallinity resulted in enhanced stiffness or weaker damping performance of the composites. In conclusion, natural plant fibers are a feasible option to modify PLA for extended applications.

The surface morphology of biomass pellets can provide data for the contact mechanics fractal model between the molding pellet and hole in biomass molding machines and for predicting wear of the molding hole. In this study, desert caragana (Caragana korshinskii) was mixed with residue from maize production, crushed, and compressed into pellets, which were used to collect data on their circumferential surface roughness profile, density, diameter, and hardness. The results showed that frictional wear occurs during contact between the forming hole and the molding particles, increasing the diameter d₀ of the forming hole and the diameter d of the molding particles. The density ρ and hardness HD of the molded pellets decreased as their diameter d increased, and the ρ and HD of caragana were higher in autumn than in summer. The values of the roughness parameters R_a, R_c and R_z of the molded particles increased with their diameter d. The maximum material rate M_r2 value of the roughness’s central profile remained at 86% with the increase of diameter d. Molded particles had surface roughness kurtosis R_ku>3 and roughness skew R_sk<0 with the increase of diameter d. The surface of molded particles was spiky and negatively skewed, and with a low number of spikes.

A wooden matched-die mold was manufactured to develop wood-based corrugated panels. Wood veneers brushed with resin were cold pressed between the mold halves and formed into a corrugated geometry. The corrugated panels were used as a core and bonded to flat veneer-based facesheets to develop sandwich panels. The whole manufacturing process involved a cold-forming technique that allowed panels to be produced with no heat. Specimens cut from both corrugated and sandwich panels were submitted to a four-point bending test to evaluate their structural performance. Adopting the same number of layers used to make the sandwich panels, flat panels were fabricated and tested to find the effect of this corrugated geometry and cold-forming process on the load-carrying capacity of the sandwich structures. A comparison with flat panels made with the same stacking of veneers showed an increase of 272% of the bending stiffness of the sandwich panels, which is known as the sandwich effect. Comparison between the bending results of the panels developed in this study with those manufactured using thermoset resin and hot-pressing technique indicated that the cold-forming process using the wooden mold is an effective and inexpensive method to develop wood-based corrugated sandwich panels.

As a consequence of increasingly serious environmental problems, many researchers are highlighting biomass materials. Cellulose, the most abundant bioresource, is becoming a key consideration for alleviating environmental pollution. Characterization of cellulosic materials is fundamental to exploring their structures and elemental contents. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) are frequently employed to study the structure of cellulose. Thus, it is urgent to combine traditional means with new ones. This study focused on the characterization of the all-cellulose composites (ACCs) model prepared via partially dissolving filter paper using 40% benzyltrimethylammonium hydroxide (BzMe₃NOH) aqueous solution. Characterized by SEM, XRD, Fourier transformation infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, the unique transformation from cellulose I to cellulose II of the ACCs model was explored. These characterization methods exhibited respective features, which could be universal ways to investigate ACCs.

A rotary kiln is a central piece of equipment for the calcination of clinker in the  production of cement. Biomass energy has been applied to rotary kilns, and solar energy has been introduced to assist the energy supply. Coupled optimization results for biomass energy and solar energy applications are compared to the single fossil energy used in the base period. A field survey and statistical analysis and integration of cement clinker production sites in China’s Central Plains Economic Zone revealed a negative linear correlation between the consumption of raw coal in the cement production process and the environmental temperature and humidity parameters of the production lines.  The energy consumption is large and the energy utilization of the system is low, with goodness of fit of R=0.962.  Coupled solar and biomass energy use in the audit period and single energy use in the base period comparison revealed a 19.5% reduction in electricity consumption, a 25.4% reduction in coal consumption and a 4.39% increase in heavy oil consumption. From 2017 to 2020, the average annual consumption cost of electricity and raw coal decreased, while the average annual consumption cost of heavy fuel oil slowly increased. After verification during the audit period, compared with the base period, the total production cost of the case enterprise can be reduced approximately 5.17%, in which the energy cost decreased 0.9%.

Energy use, together with consumption of raw materials, machine clothing, and wet end chemicals, are some of the most critical aspects in successful tissue making today. This work was aimed at developing a laboratory-scale method of estimating dewatering mechanisms, vacuum efficiency, and energy use of Through Air Drying (TAD) of tissue. When compared to pilot data, the results of the new laboratory method for investigating dewatering during TAD were in the same magnitude, around 24 to 26% dryness after vacuum dewatering, and 27 to 29% dryness after TAD molding. Sheet properties, such as caliper and surface profile, were evaluated and compared to commercial tissue sheets. The results indicate that it will be possible to precisely measure accurate dryness development and penetrated air volume for tissue sheet forming and TAD molding at a laboratory scale. This can contribute to the efforts of implementing a circular forest-based bioeconomy by increasing the fundamental understanding of dewatering of tissue paper materials, which is facilitated by improvements in energy use. The new method developed in this work will make it easier to assess ideas that are difficult to bring to pilot scale or full scale before learning more of the dewatering capabilities. The authors are convinced that improved knowledge of tissue dewatering mechanisms, forming, and material transport during and after TAD dewatering can increase the efficiency of the industrial manufacturing processes.