Volume 116, Issue 4

The global demand for sustainable materials is increasingly growing due to the synergistic effect of reducing environmental impact and enhancing properties. Date palm wastes (DPW) are considered a promising reinforcement material for polymer composites due to their abundance, biodegradability, and low cost. Combining DPW into polymer composites can enhance mechanical strength, thermal stability, and biodegradability, rendering them attractive for various applications such as structural components, automotive, and packaging. Previous studies have demonstrated the potential for enhancing the DPW reinforced polymers mechanical properties such as tensile strength, flexural strength, impact strength, and hardness by adjusting specific parameters, including preparation methods, surface treatment, processing techniques, and hybridization. This review explores the utilization of DPW in producing reinforced polymer composites, manufacturing techniques, treating methods, applications, challenges, and future perspectives.

The automotive industry is increasingly prioritizing sustainability, resulting in the use of eco-friendly materials for various components, such as brake pads. This study investigates the performance characteristics of several natural fibre based brake pads used in disc brakes by integrating experimental data and numerical analysis. Four brake pad specimens based on Jute, Coconut coir, Banana and Oil palm were fabricated via a powder metallurgy technique. Their physical and mechanical properties were experimentally determined. These properties were then used as an input for numerical analysis to evaluate the performance in terms of stress, pressure and wear depths, at three different speeds. It was concluded that wear depth of brake pad increases with increase in speed. Among them, jute based brake pad depicted minimum average wear depths whose value equal to 0.12 mm, 0.15 mm, and 0.24 mm at three speeds respectively.

This research explores the mechanical and tribological properties of bamboo fiber-reinforced epoxy composites, focusing on Phyllostachys bambusoides , a bamboo species known locally as “Bije bamboo,” sourced from the Apatani plateau, Arunachal Pradesh, India. The composites are fabricated by incorporating bamboo powder into an epoxy–hardener blend at 5 %, 15 %, and 25 % weight fractions using a manual molding process under sustained pressure for 24 h. The composites underwent a comprehensive tribological assessment, varying key parameters such as load (2 N, 5 N, 7 N), speed (50, 100, 150 cm s −1 ), and bamboo fiber content. A ball-on-disc tribometer was used to simulate wear behavior under these conditions. Profilometry, 3D surface morphology analysis, and optical microscopy are employed to assess wear depth and surface morphology. Notably, the composite containing 15 % bamboo fiber (BFC15) demonstrated superior tribological performance, achieving a low coefficient of friction ( COF ) of 0.087 at 5 N load and 50 cm s −1 speed. Additionally, it exhibited a remarkable 53 % improvement in wear resistance compared to the composite with 5 % bamboo fiber (BFC5). Surface roughness was observed to increase with higher bamboo fiber content, with BFC25 recording a maximum roughness of 17.57 µm, indicating delamination wear at higher speeds. The study confirms that the 15 % bamboo fiber composition strikes an optimal balance between mechanical strength, wear resistance, and frictional stability. These findings position bamboo-based biocomposites as a viable, sustainable alternative for industries requiring efficient wear management, particularly in automotive and aerospace applications.

In this study, discarded neem ( Azadirachta indica ) mature-wood twigs are charred at 473 K to yield charcoal ash. Material characterizations reveal that the charcoal ash is composed of various minerals and organic functionalities and has a flaky, macroporous surface consisting of protrusions. Elementary property analyses are performed, and neem mature-wood twig charcoal ash is compared characteristically with similar wood-derived, organic, and bottom ashes. The inherently gray color of charcoal ash (∼50 % absorbance and ∼50 % reflectance) changes to reddish gray when the ash solution is ultrasonicated and to golden yellow upon subsequent filtration; the emission peaks are spectrally identified as 706.32 and 577.26 nm, respectively. Thermal testing is conducted, and the following parameters are determined: thermal emissivity = 0.830–0.924; phase-transition temperature = 652.75 K; decomposition temperature = 886.85 K; enthalpy of fusion = 2,760.77 J g −1 ; enthalpy of crystallization = −3,708.41 J g −1 . The electrically conductive nature of charcoal ash is demonstrated in its solution and powdered forms, with the conductivity ranging 7–10 mS m −1 and the electrical continuity being sustained over a distance of at least 4√2 cm. Hence, this study aims to provide guidance for customizing abundantly available plant waste into valuable materials for varied target applications.

In this work, ternary nanocomposite MgO–CaO–CoO has been synthesized via a green approach using Daucus carota pomace extract as reducing and capping agent. The structure, morphology, average particle size and elemental composition of the synthesized nanocomposite were determined using different techniques including Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The Fourier transform infrared spectrophotometer spectrum showed stretching vibrations of metal oxide bonds such as Co–O, Mg–O and Ca–O at 666 cm −1 , 694 cm −1 and 721 cm −1 which confirmed the synthesis of CaO–MgO–CoO nanocomposite. X-ray diffraction study validated the crystalline structure of the ternary nanocomposite, revealing an average crystallite size of 20.33 nm. The scanning electron microscopy study revealed irregular agglomerated stone-like morphology that confirmed the formation of ternary nanocomposite. Energy-dispersive X-ray spectroscopy was used to analyze the elemental composition. The presence of elements such as calcium (Ca), magnesium (Mg), cobalt (Co), and oxygen confirmed the presence of Ca–O, Mg–O, Co–O in the synthesized nanocatalyst. The photo-catalytic activity of ternary nanocomposite (CaO–MgO–CoO) was assessed for degradation of organic pollutant, specifically RhB, under sunlight exposure. Effects of various parameters such as photocatalyst dose (5–20 mg L −1 ), solution pH (3–11) and irradiation time (30–180 min) on the extent of removal of dye showed a high degradation efficiency of 97 %. It has been deduced through a scavenger experiment, utilizing DMSO and ASC as scavenger for hydroxyl radicals (•OH) and oxide (O 2 − ) radicals respectively, that hydroxide and oxide radicals are the main reactive species in the photodegradation process.

Metal nanoparticles synthesized by the green method show remarkably different properties from bulk materials due to their size, especially in biological applications. The study’s objective is to lessen the adverse effects of synthesis processes, the chemicals they use, and the derivative substances that come from them. One practical approach in green nanotechnology is the use of various biomaterials for the synthesis of nanoparticles. In the present study, chromium nanoparticles were fabricated using Fagonia indica (LEFI) leaf extract as a reducing agent. This technique produced 46 nm-sized nanoparticles that are not only highly stable but also hold promise for a range of applications. The synthesized nanoparticles were characterized by X-ray diffraction spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, dynamic light scattering, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy. An alpha-amylase assay was used to determine the antidiabetic potential of the nanoparticles. The antioxidant activity of plant extract and chromium nanoparticles was evaluated using 2,2-Diphenyl-1-picrylhydrazyl scavenging activity. The agar diffusion method was used to test how well chromium nanoparticles killed Staphylococcus aureus and Escherichia coli . The study’s findings indicate that Cr 2 O 3 nanoparticles have potential as physiologically active agents for bio-medicinal uses, providing reassurance for their future use.

The Cr 3+ and Al 3+ ions in Ba x Sr 1− x Fe 12− y (Cr 0.5 Al 0.5 ) y O 19 decrease the saturation magnetization, and increase the coercive field. The Cr 3+ and Al 3+ doping linearly increases the magnetocrystalline anisotropic constant K . The increased dipole polarizations due to the doping ions contribute to the dielectric permittivity in the frequency range of 1–18 GHz. As a result of the increased dielectric loss, both the attenuation factor and the impedance matching are improved. While Ba 0.48 Sr 0.52 Fe 12 O 19 has no effective microwave absorption ( RL < −10 dB), the doped Ba 0.41 Sr 0.59 Fe 11.7 Cr 0.08 Al 0.21 O 19 has a bandwidth of 7.7 GHz in the frequency range of 5.6–12.3 GHz under 4 mm, and Ba 0.36 Sr 0.64 Fe 11.67 Cr 0.11 Al 0.22 O 19 with more Cr 3+ and Al 3+ ions has a bandwidth of 7.7 GHz in 6–13.7 GHz under 4 mm. The composites of Ba x Sr 1− x Fe 12− y (Cr 0.5 Al 0.5 ) y O 19 /multiwall carbon nanotubes (MWCNTs) have obviously higher dielectric loss, attenuation factor, and improved impedance matching than the corresponding compounds. The microwave absorption bandwidths of the composites are significantly widened. This is due to the fact that the composites are composed of the highly conductive MWCNTs and the dielectric Ba x Sr 1− x Fe 12− y (Cr 0.5 Al 0.5 ) y O 19 . All the composites have a bandwidth of 13.7 GHz from 4.3 GHz to 18 GHz under 4 mm. The Ba 0.48 Sr 0.52 Fe 12 O 19 /MWCNTs composite has a minimum reflection loss RL = −56 dB at a thin thickness of 2.6 mm. This work presents a promising method of designing microwave absorbing materials.

The phase equilibria of the Ce–Co–Ti ternary system at 873 K and 1,073 K were determined for the first time by using the equilibrium alloy method in combination with scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction. The ternary intermetallic compound CeCo 12- x Ti x with a ThMn 12 -type structure was detected to exist at 873 K and 1,073 K. The composition range of CeCo 12- x Ti x was measured to 7.8–14.6 at.% Ti at 873 K and 8.4–14.8 at.% Ti at 1,073 K, respectively. Due to the partial substitution of Co by Ti, the metastable binary intermetallic compound CeCo 7 with a TbCu 7 -type structure was confirmed to be stable at 873 K, and the solid solubility of Ti in CeCo 7 was determined to be 3.3 at.%. The experimental results show that the maximum solid solubility of Ti in Ce 2 Co 17 (rt), CeCo 5 , Ce 5 Co 19 , Ce 2 Co 7 (ht), CeCo 3 , and CeCo 2 at 873 K is 6.0 at.%, 1.4 at.%, 1.3 at.%, 4.1 at.%, 1.2 at.% and 2.2 at.%, respectively, while the composition ranges of Co 3 Ti, Co 2 Ti(c), and CoTi are 75.2–82.0 at.% Co, 66.0–67.5 at.% Co and 48.5–53.8 at.% Co. Meanwhile, the maximum solid solubility of Ti in Ce 2 Co 17 (rt), CeCo 5 , Ce 5 Co 19 , Ce 2 Co 7 (ht), CeCo 3 , and CeCo 2 at 1,073 K was measured to be 5.3 at.%, 2.8 at.%, 0.5 at.%, 2.8 at.%, 0.9 at.%, and 2.5 at.%, respectively, while the composition ranges of Co 3 Ti, Co 2 Ti(c), and CoTi are 74–79.7 at.% Co, 65.6–68.5 at.% Co and 51.4–53.5 at.% Co. Finally, two isothermal sections of the Ce–Co–Ti ternary system at 873 K and 1,073 K were established.