Volume 19 Issue 4

In order to address the current deficit in research on discrete elements within the context of the cotton seed pressing process, a combination of physical tests and simulation experiments were conducted on Xinluzao 84 cottonseed. The Plackett-Burman experimental design was employed to identify the parameters that had a significant impact on the accumulation angle. Subsequently, the Box-Behnken design was employed to establish a second-order regression model for the accumulation angle and the significant parameters. This resulted in the optimal parameter combination for the maximum friction coefficient, minimum sliding friction coefficient and critical shear stress being 0.207, 0.388, and 5×10⁶ Pa, respectively. In order to calibrate the cottonseed bonding parameters, a Box-Behnken test was designed based on the results of the cottonseed particle crushing test. The optimal parameter combinations of normal stiffness, tangential stiffness, and bond radius were obtained as 1.25×10⁹ N/m², 7.57×10⁸ N/m², and 0.727 mm, respectively. The obtained parameters were verified by the simulation of stacking angle and the crushing test simulation. The relative error was 0.84% and 0.46%, respectively. This serves to validate the cottonseed bonding model and simulation parameters, thereby providing a foundation for optimising the core structural parameters of the cottonseed shelling machine.

Cellulosic/lignocellulosic nanofibers (CNF/LCNF) are value-added products which recently have been considered widely. This study focused on valorization of waste by making CNF from white cutting wastepaper (WCW), which was confirmed by the transmission electron microscope images. The CNF present in the paper recycling process showed significant effects on the final product and process aspects. Addition of 5% CNF (based on dry weight of pulp) to the recycled fibers improved the strength properties as well as the fines retention. But in contrast, the drainage decreased from 303 to 188 mL CSF. Finally, considering the importance of wastepaper history on the quality of recycling process and final products, as a new vision, this study focused on recyclability of wastepaper which has experienced CNF as an additive in their history of papermaking. In this respect, the papers reinforced with nanofibers in their history, after several recycling, experienced less reduction in the tensile and tear indices and fines retention. In summary, it seems that the presence of CNF in the wastepaper can slow down the reduction of product density and process properties during several recycling cycles and so restore their potential for subsequent papermaking cycles.

Wood and steel have different physical properties. By combining the two kinds of materials as bonded parallel beams, wood-steel frame structures can be prepared. This work considers the seismic performance of such engineering structures. Based on the Rayleigh damping model of substructures, the non-proportional damping coefficient is used to quantify the structural non-proportional damping characteristic of wood-steel frame structures. A complex mode superposition method is used to calculate seismic responses. Numerical cases showed that compared with the frame structure with upper steel and lower wood, the overall lateral performance is lower and the local lateral performance is higher for the frame structure with upper wood and lower steel. The overall lateral seismic design needs to be improved for the wood-steel frame structure with upper wood and lower steel. The local lateral seismic design needs be improved for the wood-steel frame structure with upper steel and lower wood.

This study aimed to enhance the structural performance of a drift joint with a slotted-in steel plate using laminated timber made from small- to medium-diameter timbers. An analysis was conducted to compare and evaluate the structural performance and seismic behavior of laminated timber portal frames reinforced with fiber-reinforced plastic (FRP) laminates, such as glass fiber cloth (GFC), glass fiber reinforced plastic sheet (GS), and carbon-reinforced plastic sheet (CS), under low amplitude cyclic lateral loads, in comparison to unreinforced portal frames (UR). The reinforced portal frame, strengthened by FRP laminates, exhibited higher resistance to strength and stiffness strength degradation due to cyclic loading-induced degradation at low drift angles compared to the unreinforced frame affected by heterogeneous timber. The reinforced portal frame, particularly the GFC and GS, exhibited energy dissipation rates 32% and 17% higher than UR, respectively, making them the most effective in vibration damping. FRP laminates mitigated fiber direction cleavage from drift pin holes. The average maximum moment and average yield moment of the reinforced portal frame increased by 18% and 21%, respectively, due to the alleviation of joint failure. Finally, CS significantly affected the maximum moment, while GFC significantly influenced the yield moment.

Scots pine and spruce wood samples were vacuum impregnated with 3, 5, and 9% sodium bicarbonate solution. Contact angle measurements were made by dropping 0.05 mL of pure water and 3% saltwater solution onto the material’s surface. The surface roughness of each sample was measured, and that of Scots pine control samples was higher than that of spruce samples, but the surface roughness values of spruce wood were higher in the samples impregnated with sodium bicarbonate. When pure water or saltwater solution was dropped onto the samples, it was observed that as the waiting times increased, the contact angle value decreased, the droplet height decreased, and the droplet width increased. It was found that the contact angles were higher in the control samples of both tree species than in the samples of 5% and 7%. The contact angles of 9% impregnation solution, pure water, and salt water were higher than the control samples. As the solution ratio increased on the surfaces impregnated with sodium bicarbonate, the contact angle also increased, and the wettability behavior decreased accordingly. Sodium bicarbonate solution is effectively used in the impregnation process for pine and fir woods, making the materials more resistant to water under outdoor conditions. This solution significantly reduces the risk of deformation of wood by increasing the contact angle and reducing its water absorption properties.

Mechanical characteristics were studied for biodegradable plastics derived from avocado seed starch, emphasizing the influence of chitosan and glycerol. The extraction of starch from avocado seeds began with filtration. Different amounts of glycerol and chitosan were added to the extracted starch of up to 3% by weight. Because this method just uses distilled water instead of chemical chemicals, it was highly environmentally friendly. Tensile testing was done on the generated samples to assess the mechanical properties of this bioplastic; the results indicated that the samples’ elongation rates ranged from 21.9% to 134.7%. In spite of this, the bioplastic showed a comparatively low tensile strength, peaking at 3,381 MPa when chitosan-starch ratio was 2:1 and 1.5% glycerol was added.

The residue from pruning Cudrania tricuspidata trees is considered a rich source of energy and bioactive compounds. Recovering these compounds from C. tricuspidata tree pruning could help mitigate potential economic and environmental concerns. The primary aim of this study was to investigate the impact of extraction temperature, duration, and liquid-to-residue ratio on the antioxidant activity, total phenolic content, and total flavonoid content of C. tricuspidata tree pruning, using the response surface methodology. The results indicated that the microwave-assisted extraction temperature or microwave-assisted extraction time was the most crucial variable in the extraction process (Significance at p-value < 0.001 – 0.05 for antioxidant activity and chemical profile). It is worth mentioning that the optimal extraction conditions for achieving maximum 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation induction activity, total polyphenol content, and total flavonoid content were distinct from one another, necessitating specific optimization for each targeted characteristic. The optimized extraction conditions yielded 85.8% DPPH radical scavenging activity, 95.4% ABTS radical cation induction activity, 2.72 mg/g total polyphenol content, and 2.53 mg/g total flavonoid content. These results highlight the potential of C. tricuspidata as a valuable dietary source of phenolic antioxidants for human health.

The chemical compositions, antioxidant activities, and antimicrobial activities of the essential oils acquired from the separated parts of air-dried flowers, leaves, and stems of Alyssoides utriculata L. plant growing in Turkiye were determined. Three volatile oil components were acquired via hydrodistillation using a Clevenger apparatus and analyzed by the Gas Chromatography-Mass spectrometry/Flame Ionization Detection (GC-MS/FID) analysis. A total of 75, 67, and 76 compounds in the volatile oils of flower, leaves, and stem of A. utriculata were identified, respectively. The highest percentage of chemical compounds in the essential oils of A. utriculata were determined to be monoterpenes in flowers and leaves, (72.4% and 66.5%) and hydrocarbons (29.2%) in stems. While α-pinene (62.5% and 46.7%) was defined as the major compound in the flowers and leaves, nonane (21.2%) was determined to be so in the stem essential oil. The antioxidant activity of the obtained essential oils was determined according to free radical scavenging and total phenolic content (TPC), and antimicrobial activity against 12 bacteria and 5 fungi, using the agar dilution method. The amount of TPC and scavenging activity of the flower oil were found to be 440.61 ± 6.26 mg GAE/L and 46.00 ± 1.28%, respectively. Based on the antimicrobial activity results, all the essential oils of A. utriculata were determined to have antimicrobial activity against Escherichia coli and Bacillus subtilis.

The antibacterial performance of biocomposite films prepared from lignocellulosic waste (hazelnut husk or hazelnut leafy green cover) modified with silver nanoparticles and polylactic acid (PLA) was determined. The amount of hazelnut husk in the PLA matrix ranged from 10 to 40% by weight in 10% increments. The composite pellets were produced using a twin-screw extruder. Biocomposite films of 0.6 mm x 40 mm x 200 mm were produced from the pellets in a laboratory hydraulic hot press. The surfaces of the modified hazelnut husk and biocomposite specimens were analyzed by scanning electron microscopy (SEM) and inductively coupled plasma optical emission spectrometry (ICP-OES). The antibacterial activity of the biocomposite films against Staphylococcus aureus bacteria was determined using the ASTM E 2149 (2020) method. The antibacterial activity of the biocomposite films increased noticeably with the addition of hazelnut husk modified with the silver nanoparticles. Compared to the pure PLA film, the biocomposite films with 10 wt% modified husk flour showed the lowest antibacterial activity (31.3%) against S. aureus over 24-h while the films with 40 wt% showed the highest antibacterial activity (99.9%). The biocomposite films made of hazelnut husk flour with silver nanoparticles and PLA matrix could be considered for food packaging applications.

Mixtures of vegetable waste and leaves were used to prepare compost in piles. The carbon/nitrogen ratios of the biomass varied among the selected agricultural waste. Co-composting was carried out for six weeks with a starter culture. The organic matter of the leaves declined after four weeks of composting, and a stable compost was obtained after 42 days of composting. The compost temperature reached its maximum after 12 days and moisture content declined continuously up to 42 days. The pH value of the compost increased slowly during composting and reached a maximum after six weeks. The electrical conductivity of the compost was suitable for plant nutrition. The organic matter, as organic carbon, declined, and organic nitrogen was increased. The carbon/nitrogen ratio of the mature compost was decreased. The decreased levels of carbon/nitrogen ratio reflected the maturity of the compost. The organic matter (%) was maximum (>50%) before composting process and it decreased gradually. The seed germination index was higher after 42 days of composting. The compost-treated plant improved yield and green gram seeds showed the presence of antioxidant enzymes.