To reduce the emission of harmful materials into the ecosystem, researchers have been exploring the potential of manufacturing polymeric composites based on natural fibres. Although the large area of application of these materials has encouraged investigations of their performance under various loading conditions, less research has been conducted on their tribological behaviour. Hence, in this study, tribological tests were conducted on epoxy composites based on bamboo fibres. The wear performance of bamboo fibre reinforced epoxy was tested using various operating parameters, and the worn surfaces were examined using optical microscopy. The results revealed that the specific wear rate of the composites reduced since the epoxy was reinforced with bamboo fibres. Scanning electron microscopy analysis showed different wear mechanisms and damages.

This research examines the friction and dry wear behaviours of glass fibre-reinforced epoxy (GFRE) and glass fibre-reinforced polyester (GFRP) composites. Three fibre orientations—parallel orientation (P–O), anti-parallel orientation (AP–O), and normal orientation (N–O)—and various sliding distances from 0–15 km were examined. The experiments were carried out using a block-on-ring configuration at room temperature, an applied load of 30 N, and a sliding velocity of 2.8 m/s. During the sliding, interface temperatures and frictional forces were captured and recorded. Worn surfaces were examined using scanning electron microscopy to identify the damage. The highest wear rates for GFRE composites occurred in those with AP–O fibres, while the highest wear rates for GFRP composites occurred in those with P–O fibres. At longer sliding distances, composites with P–O and N–O fibres had the lowest wear rates. The highest friction coefficient was observed for composites with N–O and P–O fibres at higher sliding speeds. The lowest friction coefficient value (0.25) was for composites with AP–O fibres. GFRP composites with P–O fibres had a higher wear rate than those with N–O fibres at the maximum speed.

Despite the extensive research on biodiesels, further investigation is warranted on the impact of compression ratios on emissions and engine performance. This study addresses this gap by evaluating the effects of increasing the engine’s compression ratio on engine performance metrics—brake-specific fuel consumption (BSFC), power, torque, and exhaust gas temperature—and emissions—unburnt hydrocarbons (HCs), carbon dioxide (CO₂), carbon monoxide (CO), nitrogen oxides (NO_x), and oxygen (O₂)—when fueled with a 20% blend of waste cooking oil biodiesel (WCB20) and petroleum diesel (PD) under various operating conditions. The viscosity of the prepared fuels was measured at 25 °C and 40 °C. Experiments were conducted on a single-cylinder diesel engine under wide-open throttle conditions at three different speeds (1400 rpm, 2000 rpm, and 2600 rpm) and two compression ratios (16:1 and 18:1). The results revealed that at a lower compression ratio, both WCB20 and petroleum diesel exhibited reduced BSFC compared to higher compression ratios. However, increasing the compression ratio from 16:1 to 18:1 significantly decreased HC emissions but increased CO₂ and NO_x emissions. Engine power increased with engine speed for both fuels and compression ratios, with WCB20 initially producing less power than diesel but surpassing it at higher compression ratios. WCB20 demonstrated improved combustion quality with lower unburnt hydrocarbons and carbon monoxide emissions due to its higher oxygen content, promoting complete combustion. This study provides critical insights into optimizing engine performance and emission characteristics by manipulating compression ratios and utilizing biodiesel blends, paving the way for more efficient and environmentally friendly diesel engine operations.

The growing need for sustainable materials in engineering applications has led to increased interest in the use of waste-derived ceramics as reinforcing fillers in polymer composites. This study investigates the mechanical and tribological performance of epoxy composites reinforced with Yttria-Stabilized Zirconia (YSZ) waste ceramics, focusing on the effects of varying ceramic content (0–40 wt.%). The results demonstrate that while the tensile strength decreases with increasing ceramic content, the wear resistance and surface hardness improve, particularly at 20 wt.% YSZ. These findings are highly relevant for industries such as automotive, aerospace, and industrial manufacturing, where the demand for eco-friendly, high-performance materials is growing. This work aligns with the journal’s focus on sustainable engineering by offering new insights into the practical application of waste materials in high-performance composite systems.

Growing interest in sustainable fuel alternatives has intensified efforts to improve biodiesel engine performance, particularly through additive-based fuel modification. However, most existing studies rely on engineered nano-additives under controlled laboratory conditions, and limited evidence exists regarding the real-world effectiveness of commercially accessible non-nano additives. This study investigates the impact of blending ethylene glycol monobutyl ether (EGBE), a commercially available glycol-ether additive, with cottonseed biodiesel (CSB) on fuel properties, combustion behaviour, engine performance, and emissions in a single-cylinder diesel engine operated at 1600, 2000, and 2400 rpm. The novelty of this work lies in evaluating a practical additive formulation under realistic operating conditions and contrasting its effects with the catalytic mechanisms commonly reported for nano-enhanced fuels. Fuel characterisation showed viscosity reductions of 5.2% and 10.2% at 15 °C for 5% and 10% blends, respectively, with greater reductions at 40 °C, indicating improved biodiesel fluidity. Combustion analysis revealed minimal changes in ignition delay, peak pressure, and combustion phasing relative to neat biodiesel, confirming that the additive primarily modifies physical properties rather than oxidation chemistry. Brake specific fuel consumption decreased slightly at higher speeds due to improved spray behaviour, while brake power and torque remained comparable to pure biodiesel but below diesel. Emissions (CO, HC, CO₂, and NOₓ) followed typical biodiesel trends with no significant catalytic enhancement observed. The addition of ethylene glycol monobutyl ether reduced biodiesel viscosity by 5.2% and 10.2% for 5% and 10% blends at 15 °C, with greater reductions at 40 °C, indicating improved fuel fluidity. However, combustion characteristics showed no significant change in ignition delay, peak pressure, or combustion phasing. Engine performance remained largely unaffected, with only marginal improvements in brake specific fuel consumption at higher speeds, while emissions followed typical biodiesel trends with no measurable additive influence. These results confirm that glycol-ether additives provide modest physical-property improvements but do not enhance combustion behaviour or replicate the effects of nano-scale catalytic additives. .