Natural polyphenols found in plants are secondary metabolites and act as natural antioxidants. Phenols prevent lipid oxidation by donating their hydrogen to free radicals generated between reactions of oxygen with unsaturated fatty acids. This work aims to examine turmeric extract for its capacity to act as an antioxidant and pour point depressant additive in biolubricants. The study involved extracting turmeric rhizome and analyzing the extract using the gas chromatography-mass spectrometry (GC-MS) and Fourier-transform infrared spectroscopy (FTIR) techniques to identify phenolic compounds and the nature of bonds in terms of abundance peak areas. The yield of concentrated turmeric rhizome extract by weight was 3.7%. The FTIR analysis revealed O-H band at 3336 cm⁻¹, C-H asymmetric and symmetric stretching at 2940 and 2834 cm⁻¹, C=C cyclic ring at 1680–1515 cm⁻¹. The phenols detected by the GC-MS technique are phenol, 2 -methoxy-3-(2-propenyl) occupying 36.3% area at 16.5 min retention time and Phenol, 2-methoxy-4-(2-propenyl)-, acetate having 3.8% area at 3.8 min retention time. The results show promising capacity of turmeric rhizome extract to act as antioxidant and pour point depressant additive in biolubricants.

Piston top rings in the combustion engine play a crucial role in the overall hydrodynamic performance of engines, such as power loss, minimum film thickness and friction forces, by ensuring sealing and minimizing the leakage of burnt gases. This present paper examines the influence of four key parameters of the top ring, such as ring width, ring temperature, ring tension, and ring surface roughness on the hydrodynamic behavior at the ring/cylinder contact. These parameters play a significant role in the formation and maintenance of the oil film, directly influencing hydrodynamic indicators such as the minimum oil film thickness, friction force, power loss, oil pressure, and the ring angle twist. This article relies on hydrodynamic models and numerical simulations performed using GT-SUITE version 6 software to analyze these effects. The pressure curve used in this simulation is experimentally validated for an engine speed of 2000 RPM. It was found that an increase in the top ring temperature reduces the oil’s viscosity, decreasing the film thickness and increasing the risk of metal-to-metal contact. Increasing the roughness of the ring enhances oil film stability, especially at the bottom dead center (BDC) points during each phase of the operating cycle. Further, three different types of ring profiles were investigated for friction forces by varying the speed of the engine.

The growing demand for accurate and computationally efficient combustion mechanisms for simulations has driven significant advances in chemical kinetic mechanism reduction for multicomponent fuels. This review systematically examines the evolution of reduction methodologies, from early size- and stiffness-reduction techniques to modern construction-based and optimisation-driven strategies. Key approaches including directed relation graph (DRG) methods, sensitivity analysis, path flux analysis, computational singular perturbation (CSP), and genetic algorithms are critically assessed. The review further explores the foundational kinetic mechanisms of hydrocarbons, alcohols, ethers, and esters, highlighting the hierarchical role of C₀–C₄ core chemistry in multicomponent fuel oxidation. It provides a consolidated understanding of reduction strategies and workflows; highlights access to detailed kinetic mechanisms for practical fuels. A central finding is that co-oxidation interactions between fuel components significantly influence combustion behavior and must be explicitly retained in reduced mechanisms. Despite substantial progress, challenges remain in developing universal reduction frameworks, establishing standardised validation datasets, and achieving fully automated mechanism construction. This review provides a roadmap for researchers seeking to implement skeletal/reduced chemical kinetic models in multidimensional engine simulations while retaining chemical fidelity across wide operating conditions.