Research Articles

Using environmentally friendly additives has been considered widely in different industries, especially papermaking, which has a high dependency on additives. The current study focused on applying a plant-based gum obtained from Astragalus gossypinus (a well-known plant in some regions of the world, especially Iran) in the papermaking process. The gum characterization showed a high content (about 84%) of carbohydrates (mainly hemicellulose with xyloarabinan monomers in the main chain and about 8% of uronic acid in the side chains), low ash content (2.58%) and insignificant protein content. FTIR spectra confirmed the structural results. The weight average molecular weight (M_w) and polydispersity of tragacanth gum were 4867 × 10³ g/mol and 1.423, respectively. Considering the mechanical strengths results, applying the gum in recycled pulp improved tensile, burst, bending, and tear indices significantly. Moreover, fines retention experienced a significant increment by applying up to 2% of the gum. The pulp drainage decreased consequently by increasing the dosage of gum. The FESEM images confirmed the higher retention and bonding in paper structure by applying the gum. The results seem to open a new door for the application of different plant gums as a green additive for papermaking industries.

A 3² factorial experimental design was conducted to evaluate the effects of pH and anionic trash catcher (ATC) dosage on Cobb number (1 min), cationic demand, and conductivity in softwood kraft pulp sizing with Alkenyl Succinic Anhydride (ASA). Results indicated that acidic conditions tended to enhance ASA’s reaction with cellulose, leading to superior hydrophobicity (Cobb number, 1 min = 23 g/m² at pH 4.0 and 121 µeq/L cationic demand). Statistical analysis confirmed that pH exerted a stronger influence on ASA performance (p-value 2.0×10^-7) compared to ATC dosage (p-value 0.0297), while conductivity had minimal effect. The findings suggest that optimizing ASA application in acid conditions improves water resistance, reducing reliance on high ATC dosages. This study provides valuable insights into ASA application strategies for papermaking, particularly in furnishes that do not require alkaline conditions to retain fillers, by optimizing wet-end chemistry control for enhanced sizing efficiency.

This study investigated the effect of crushed corn cob reinforcement on the compressive strength of composite materials with a hybrid matrix based on dammar (60%) and a synthetic epoxy (Resoltech 1050 with 1058s hardener). While previous research has explored mechanical and chemical properties of such composites, as well as the role of dammar resin, the specific impact of crushed corn cob on compressive strength had not yet been addressed. Materials with reinforcement mass fractions between 50% and 67% were fabricated, each with 15 samples. Power Analysis confirmed the sample size was statistically valid. A null hypothesis—stating that crushed corn cob has no significant influence on compressive strength—was tested and rejected (p < 0.05) using one-way ANOVA. Welch ANOVA confirmed the result (Fw > 2.49), and Kolmogorov-Smirnov tests showed data normality (p > 0.05). Post hoc ANOVA with Bonferroni correction confirmed significant differences between groups. The key finding was that beyond 66% crushed corn cob content, the materials lose engineering relevance due to inadequate compressive strength.

Due to challenges associated with hydrogen storage and transportation, on-site hydrogen production has garnered significant attention. However, achieving a balance between efficiency and cost remains a critical challenge in the catalytic conversion of ammonia to hydrogen. Catalysts utilizing carbon fiber supports derived from cellulose, which contain a high carbon content, have demonstrated promising dehydrogenation activity in ammonia pyrolysis. One such catalyst component is steel fiber which contains a high content of transition metals and serves as a connection between the carbon element and the metals, which would enhance its catalytic properties. In this study, the catalytic performance of commercial steel fiber for hydrogen production via ammonia pyrolysis was investigated. Activity tests and analytical characterizations revealed that the steel fiber catalyst exhibited excellent catalytic activity, stability, and cyclic performance, enabling COX-free hydrogen production. Characterization results indicated that the catalyst contained over 80 wt% iron atoms and exhibited low surface area. The Fe atoms were further converted into stable Fe-N bonds, with the number of Fe-N bonds decreasing as the reaction temperature increased, thereby accelerating the desorption rate of nitrogen atoms on the catalyst surface and enhancing conversion efficiency.

A watery extract of Schinus terebinthifolia leaves was used as the source for producing a nanocomposite of ZnO/CuO/Se (NC ZnO/CuO/Se). Transmission electron microscopy (TEM), UV, X-ray diffraction, and scanning electron microscopy-energy were employed to characterize NC ZnO/CuO/Se. Based on the TEM investigation, the nanoparticles had an average size between 40.9 and 50.2 nm. NC ZnO/CuO/Se had potent anti-H. pylori activity, as evidenced by a zone of inhibition of 34.3 mm. The NC ZnO/CuO/Se successfully inhibited H. pylori (MIC = 15.6 μg/mL) and showed better antimicrobial activity in comparison with the control. At 75% of MBC, it dramatically decreased the production of bacterial biofilms (91.1% inhibition). High antioxidant qualities were demonstrated by the NC ZnO/CuO/Se (> 88% in the DPPH assay). It demonstrated outstanding enzyme inhibition capacity against lipase, with an IC₅₀ of 41.66 ug/mL. The IC₅₀ value of NC ZnO/CuO/Se against normal cell lines (WI38) was 593.08 ± 2.35  µg mL^–1, which is a high dose. From the overall results, NC ZnO/CuO/Se exhibited favorable biological effects in vitro as a wide-spectrum treatment for various medical uses.

The applications of wood are limited by its hygroscopicity and resulting dimensional changes, which reduce its service life for outdoor conditions. Modification methods develop the usages of wood-based products by altering the structure. This study compared the effect of oil heat treatment (OHT) with raw (SO) and epoxidized soybean oil (ESO) at different temperatures relative to the practical properties of eucalyptus wood. Fourier transform infrared spectra confirmed hemicellulose degradation with increasing temperatures of ESO-treated specimens. With increasing temperature, ESO darkened the specimens compared to SO. Thermal modification at the highest temperature in ESO resulted in a weight loss of modified specimens and the lowest density, with more hydrophobicity and dimensional stability compared to the SO-modified specimens. Based on bending data, unlike modulus of elasticity (MOE), modulus of rupture (MOR) did not show a statistical difference between the two types of oils, except at 150 °C. At 200 °C, the specimens modified with ESO exhibited lower hardness than SO. The impact resistance of 150 and 175 °C/ESO modified specimens was higher than SO specimens. In summary, functionalized vegetable oil significantly improved physical characteristics compared to SO, with obvious improvement in impact strength at 150 °C.

With the recovery of the economy and growth of living standards, the demand for wood furniture is increasing, leading to a focus on wood quality and market value. Mid-infrared (MIR) spectroscopy, which characterizes molecular vibrations, is well-suited for wood classification due to its ability to identify molecular structures. This study utilizes a Fourier Transform Infrared (FTIR) spectrometer to classify 31 wood species based on their commercial categories. While the basic composition of wood species is similar, spectral data are overall close, necessitating a robust approach for accurate identification. To address this, a two-dimensional transformation of the spectral data is performed, to convert wavenumber sequence and state transition probabilities (quantized intensity levels) of spectra into a matrix, followed by deep learning classification using the transformed data. This resulted in the development of the MTF-SKNet model, achieving a classification accuracy of 93% for wood species. The model demonstrated strong generalization performance, reaching 96% accuracy in classifying the rosewood category of woods.

The scientific community is actively developing innovative nanomaterials with broad-spectrum antimicrobial properties. In this study, moringa gum-derived polymeric carbon dots (MGCDs) were synthesized via a rapid and eco-friendly microwave irradiation technique using aqueous moringa gum as the precursor. The resulting MGCDs exhibited strong green fluorescence under UV light, with a UV-Vis absorption peak at ~290 nm and excitation-dependent fluorescence at 360 nm. They demonstrated significant antioxidant activity, achieving 87% DPPH scavenging efficiency at 0.9 mg/mL, comparable to ascorbic acid. Zeta potential analysis confirmed high colloidal stability, with values of 29 ± 0.9 mV (DI water), 30 ± 0.8 mV (SBB), 28 ± 9 mV (PBS), and 23 ± 0.8 mV (DMEM). Hydrodynamic sizes ranged from 86 ± 3 nm to 135 ± 4 nm, indicating solvent-dependent dispersion. TGA showed high thermal stability, while XRD confirmed an amorphous carbon structure with a broad peak at 22°. MGCDs demonstrated the antibacterial activity against Staphylococcus aureus and Bacillus subtilis, resulting in inhibition zones of 17.4 ± 0.8 mm and 15.2 ± 0.6 mm, respectively, at 40 mg/mL. Their multifunctionality, simple synthesis, and cost-effectiveness highlight their potential in bioimaging, antimicrobial applications, and fluorescent materials.

Nests made by the Najdian termite, Microtermes najdensis, were studied. The climate, soil, intact wood, and nest wall were investigated. The entryways of the termite nests were located at the southwest direction, which promotes better ventilation. The internal temperature (IT) was warmer than the outer temperature (OT) during cold days, while it was cooler than the hottest OT on hot days, and vice versa. The IT had more constancy than the OT. Moreover, the IT trended toward the upper OT’s limit, indicating that termites prefer the hotter atmospheres. Lignin is the prominent tracer of the organic matter used as a binder for the nest wall due to its gluability and resistance to enzymatic or fungal degradation. Features resembling microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC) were discovered for the first time in the nest mortar reinforcing Klason lignin. Their presence was attributed to enzymatic hydrolysis by the termites and/or their accompanying fungal community. The gross heat of combustion (GHCs) of the intact wood and nest wall were studied. Finally, a theory illustrating the fabrication of termite nests was postulated.

Single-layer particleboards were fabricated from rice straw bonded with chitosan. The rice straw was pre-treated by steam explosion to reduce the extractives and ash contents. The obtained pulp was analyzed for chemical composition, which indicated that the steam explosion pretreatment effectively decreased the extractives and ash contents. The effects of steam explosion pretreatment and chitosan contents on mechanical properties and dimensional stability of rice straw particleboards were explored. The mechanical properties and dimensional stability of particleboards made of steam exploded rice straw showed significant improvement. Addition of chitosan increased the mechanical properties and dimensional stability of particleboards. The mechanical properties and dimensional stability of particleboards improved with the increase of chitosan content.