Search Results (7)

Cellulose-based paper products derived from agro-industrial waste have attracted considerable interest due to their potential in sustainable material development. In this study, bacterial cellulose (BC) residue from the food and beverage industry was employed as a reinforcing agent to fabricate high-performance paper composites by blending with eucalyptus pulp (EP) at various ratios and basis weights. These papers were coated with a cationic modified starch solution (MS) using a rod coater, followed by hot pressing. Mechanical strengths (TAPPI Standard), water resistance (Cobb test and water contact angle), and air permeability (ASTM D737) were evaluated to assess material performance. The results showed that incorporating 50 wt% BC produced paper with outstanding mechanical performance, characterized by a high tensile index and excellent tear resistance. The application of the MS coating significantly boosted water resistance and air barrier performance, underscoring the effectiveness of this approach in creating high-performance paper materials. The resulting coated composites demonstrated excellent mechanical strength and barrier properties, positioning them as promising candidates for filtration applications such as personal protective face mask membranes. Full article

The continuous requirement for pre-bleaching processes on kraft pulp, employing a range of compatible enzymes, aims to mitigate the pollution caused by chemical bleaching agents. In the present study, the laccase-producing bacterium Bacillus licheniformis BK-1 was isolated from the Bakreshwar hot spring in India and tested for laccase production using different lignocellulosic substrates. The isolate was found to produce maximum laccase (8.25 IU/mL) in the presence of rice bran as a substrate, followed by 5.14 IU/mL using sawdust over a 48 h period. Laccase production doubled when medium parameters were optimized using a central composite design. The bleaching of rice straw pulp was accomplished using a laccase, xylanase (previously extracted from the same bacteria), and laccase–xylanase mixture. The mix-wood kraft pulp treated with the enzyme mixture at pH 7.0 and 50 °C temperature for up to 180 min reduced the chlorine amount by 50% compared to the control. The results also revealed that the enzyme mixture improved the pulp’s optical (brightness 10.39%) and physical (tear index 39.77%, burst index 22.82%, and tensile strength 14.28%) properties with 50% chlorine dose. These exceptional properties underscore the enzyme mixture’s suitability for pulp pre-bleaching in paper manufacturing, offering a safer and more environmentally friendly process. Full article

To extend the application of cost-effective high-yield pulps in packaging, strength and barrier properties are improved by advanced-strength additives or by hot-pressing. The aim of this study is to assess the synergic effects between the two approaches by using nanocellulose as a bulk additive, and by hot-pressing technology. Due to the synergic effect, dry strength increases by 118% while individual improvements are 31% by nanocellulose and 92% by hot-pressing. This effect is higher for mechanical fibrillated cellulose. After hot-pressing, all papers retain more than 22% of their dry strength. Hot-pressing greatly increases the paper’s ability to withstand compressive forces applied in short periods of time by 84%, with a further 30% increase due to the synergic effect of the fibrillated nanocellulose. Hot-pressing and the fibrillated cellulose greatly decrease air permeability (80% and 68%, respectively) for refining pretreated samples, due to the increased fiber flexibility, which increase up to 90% using the combined effect. The tear index increases with the addition of nanocellulose, but this effect is lost after hot-pressing. In general, fibrillation degree has a small effect which means that low- cost nanocellulose could be used in hot-pressed papers, providing products with a good strength and barrier capacity. Full article

The widespread use of petroleum-based products has led to increasing environmental and ecological problems, while the extraction and application of various natural cellulose fibers have received increasing attention. This research focuses on the extraction of cellulose fibers from cow dung using different treatments: hot water, hydrogen peroxide (H₂O₂), sodium hydroxide (NaOH) and potassium hydroxide (KOH) boilings, as well as a selection of the best quality cow dung fibers for papermaking with quality control. The study’s objective is to find a sustainable method to extract as much material as possible from renewable biomass feedstock. The results show that the best extraction rate is obtained by KOH boiling with 42% cellulose fibers extracted. Corresponding handmade paper has a burst index of 2.48 KPam²/g, a tear index of 4.83 mNm²/g and a tensile index of 26.72 Nm/g. This project expands the sources of natural cellulose fibers to an eco-friendly and sustainable one and opens up new applications for cow dung. Full article

We determined the effects of two extracts from Acer palmatum Thumb. leaves (hot water extract KIOM-2015EW and 25% ethanol extract KIOM-2015EE) in a benzalkonium chloride (BAC)-induced dry eye mouse model. Dry eye was induced by 0.2% BAC for 2 weeks, followed by treatment three times (eye drop) or once (oral administration) daily with KIOM-2015E for 2 weeks. Treatment with both KIOM-2015EE and KIOM-2015EW resulted in a marked increase in tear volume production for the 4 days of treatment. The Lissamine Green staining score, TUNEL-positive cells, and inflammatory index were significantly decreased after 2 weeks. Topical KIOM-2015EE administration exhibited a greater improvement in decreasing the ocular surface staining scores, inflammation, dead cells, and increasing tear production in a dose-dependent manner compared with the other groups. Furthermore, KIOM-2015E significantly reduced the phosphorylation of NF-κB, which was activated in the BAC-treated cornea. Topical administration was much more effective than oral administration for KIOM-2015E and KIOM-2015EE was more effective than KIOM-2015EW. Application of KIOM-2015E resulted in clinical improvement, inhibited the inflammatory response, and alleviated signs of dry eye. These results indicate that KIOM-2015E has potential as a therapeutic agent for the clinical treatment of dry eye. Full article

Ti/Al multilayered composites (LMCs) with different layers were prepared by hot-pressing and hot-rolling. The effects of interface on the deep drawability of LMCs were explored. The results indicate that LMCs with more layers have a higher limit-drawing ratio (LDR) and exhibit an excellent deep drawability. The texture strength of the Ti layer gradually weakens with the increase of layers, which leads to the smaller yield ratio (σ_s/σ_b), the plastic strain ratio (r), and the larger strain hardening index (n), thus the deep drawability of LMCs with more layers is enhanced effectively. The Ti/Al interfaces in three, five, and seven layers of LMCs exhibit straight, small wave-like interlocking, and dense serrated structures at the corner of the cylindrical parts, respectively. The component metals become thinner with the increase of layers, and the increased interfacial pressure promotes the formation of an increasingly firm overlapped interfacial structure. The load transfer via the interfaces makes the stress distribution between layers more uniform with the increase of layers, which helps to coordinate deformation. Deflection and tearing occur when the cracks propagate to the interface due to the complex stress state, which hinders and delays the crack penetration, thereby improving the deep drawability of LMCs with more layers. Full article

The main reason for the use of returnable material, or recycled alloys, is a cost reduction while maintaining the final properties of the casting. The casting resulting quality is directly related to the correct ratio of commercial grade alloy and alloy made by remelting the returnable material in the batch. The casting quality is also affected by the purity of the secondary raw materials used, the shape complexity and the use of the casting itself. The presented article focuses on the effect of increasing the returnable material content in the batch on the hot tearing susceptibility of AlSi9Cu3 alloy. Hot tears are a complex phenomenon that combines metallurgical and thermo-mechanical interactions of the cast metal. Hot tearing susceptibility was evaluated on the basis of quantitative (HTS—hot tearing susceptibility index) and qualitative evaluation. The negative effect of returnable material in the batch was already manifested at a 20% content in the batch. The critical proportion of the returnable alloy in the batch can be stated as 50%. The alloy with a 50% returnable material content manifested insufficient results of the HTS index and qualitative evaluation, which means increased sensitivity to tearing. The negative effect of returnable material and the increased sensitivity were also confirmed in the evaluation of the fracture surface and hot tear profile. The microstructure of alloys with 50% and higher proportion of returnable material was characterized by a higher amount of iron phases (mainly Al₅FeSi), whose sharp ends acted as critical regions of hot tearing and subsequent hot tear propagation, which had a major impact on the increase in hot tearing susceptibility. Full article