The methanolic leaf extract of Grewia tenax (Gt) was evaluated as a green corrosion inhibitor for C38 steel in 1 m HCl. Liquid chromatography-electrospray-high-resolution mass spectrometry tentatively assigned 26 constituents to four families of oxygen-rich metabolites: oleanane-type saponins, kaempferol and naringenin oligoglycosides, hydrolysable tannins and proanthocyanidins; attenuated total reflectance Fourier-transform infrared spectroscopy confirmed abundant hydroxyl, carbonyl and glycosidic functionalities. Weight loss, polarisation and impedance spectroscopy gave consistent efficiencies of 94.9%, 95.8% and 93.6% at 2500 ppm and 293 K. The corrosion potential shifted by at most 11 mV, far below the 85 mV threshold, establishing mixed-type behaviour. The charge-transfer resistance rose 15-fold, from 19.5 to 304.5 Omega cm(2), and reached 750.8 Omega cm(2) after 24 h, showing that the film consolidates rather than degrades. Adsorption follows the Langmuir isotherm (R-2 = 0.9999), with Delta G degrees(ads) = -21.1 kJ mol(-1) obtained on an explicit mass-based standard state, indicating predominantly physical adsorption with a chemical contribution supported by the spectrum of the recovered film, in which the nu(O-H) band shifts from 3300 to 3410 cm(-1) and a carbonyl band appears at 1733 cm(-1). Scanning electron microscopy and energy-dispersive X-ray spectroscopy show the cracked corrosion-product layer replaced by a crack-free surface bearing globular organic aggregates over a restored iron signal.
In the pursuit of more sustainable electronics, this study explores the incorporation of carbonized spent coffee grounds (SCGs) into honey-based resistive switching memory devices. SCGs, a by-product of coffee production, were thermally treated at 150, 350, 450, and 500°C to modify their carbon content and surface functional groups. The treated SCGs were incorporated into honey, a natural polysaccharide, to form a composite memristive layer. Thin films were prepared by spin-coating and drying, followed by fabrication of Au/carbonized SCGs-honey/indium–tin–oxide (ITO) devices using sputtered Au and ITO as the top and bottom electrodes, respectively. Thermogravimetric analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy indicated that increasing the treatment temperature increased carbon content, structural disorder, and carbonyl-group density while reducing hydroxyl-group content. Current–voltage measurements showed that the ON/OFF ratio increased from approximately ∼101.35 to ∼102.27 corresponding to an approximately eightfold increase. The memory window decreased by 0.34 V, from 2.30 to 1.96 V, for devices containing SCGs treated at 500°C compared with those containing undried SCGs. These findings demonstrate that thermally treated SCGs can enhance the resistive switching performance of honey-based thin films.
Natural polymer-based materials incorporating bioactive agents are widely explored for biomedical applications due to their biocompatibility and sustainability. In this study, a konjac gum-based film loaded with olive oil and norfloxacin (KG@OO + NOR) was developed as an antibacterial wound dressing. The film was characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mechanical analysis, confirming good structural integrity, thermal stability, and acceptable mechanical properties. It exhibited a high swelling ratio (294 +/- 17%) and a suitable water vapor transmission rate (242 +/- 22 g m(-2)d(-1)), indicating its ability to maintain a moist wound environment. Morphological analysis showed uniform dispersion of olive oil droplets, while FTIR results suggested strong intermolecular interactions. The film demonstrated effective antibacterial activity against Staphylococcus aureus and Escherichia coli. In vitro cytocompatibility studies using human skin fibroblast cells showed sustained viability over 72 h, and scratch assay results indicated complete wound closure. These findings suggest that the KG@OO + NOR film is a promising candidate for antibacterial wound dressing applications.
Recycling waste asphalt is increasingly important amid growing highway maintenance demands and environmental concerns, yet volatile organic compound (VOC) emissions during recovery remain poorly understood. This study investigates how waste soybean oil (WSO) affects VOC emissions and regeneration properties of aged 70# asphalt. WSO was blended at 4%, 6%, 8%, and 10% concentrations and characterized by way of gas chromatography-mass spectrometry, Fourier transform infrared (FTIR), and gel permeation chromatography. Rheological performance was evaluated using a dynamic shear rheometer (high-temperature) and bending beam rheometer (low-temperature), with microstructure observed by atomic force microscopy (AFM). Results show WSO significantly reduces VOC emissions - 8% WSO achieves a 33.23% reduction against unmodified asphalt, with notable decreases in toxic aromatics and sulfur-containing compounds. Molecular analysis revealed WSO replenishes light and aromatic components, restoring colloidal stability to 92% of unaged asphalt while inhibiting oxygen-and sulfur-containing compound formation. Performance tests showed that 8% WSO provides high-temperature rutting resistance comparable to new asphalt and reduces low-temperature creep stiffness to 46.9% of aged asphalt, improving crack resistance. AFM confirmed that WSO alleviates asphalt aggregation and optimizes colloid structure. Therefore, 8% WSO is the optimal dosage, achieving the best balance between VOC inhibition and regeneration performance.
In the present investigation, optimization of the viscoelastic and mechanical properties of a functionalized multi-walled carbon nanotube (MWCNT) and carbon fiber-reinforced epoxy nanocomposite was carried out. The process parameters used in this investigation are content (wt.%), sonication time (min), and ball milling duration (min). Taguchi orthogonal array (L9) was employed to design the experimental runs and study the effect of each parameter on the responses. Response variables used in this investigation are storage modulus, loss modulus, glass transition temperature (Tg), and tensile strength. A regression model in terms of process variables was developed and validated through confirmation experiments performed at the optimum conditions of 2 wt.% MWCNTs, 60 min of sonication, and 180 min of ball milling. The predicted and experimental values of storage modulus (41.815 against 38.2 +/- 4.05 GPa), loss modulus (3.94 against 3.89 +/- 0.15 GPa), Tg (138.81 against 135 +/- 9.94 degrees C), and tensile strength (941.45 against 942 +/- 28.59 MPa) were found to be in close agreement, confirming the reliability of the developed models. Microstructural examination of the optimized composite using microscopy revealed a uniform dispersion of MWCNT's within the epoxy matrix, contributing to the improved interfacial bonding and load transfer.
