The pre-intercalation of Na+ ions in layered birnessite-MnO2 is shown to have a dramatic influence on its electrochemical properties.

Quenching is a process involving rapid cooling in quenching media and hardening of steels. The effect of quenching process on the microstructure and mechanical properties (hardness) are studied and elaborated in this thesis. The quenching media uses including conventional fluid (distilled water and mineral oil), nanofluid (TiO2 nanofluid), and hybrid-based nanofluid (TiO2 hybrid nanofluid). Thermal conductivity and microstructure development are closely-linked to each other. Conventional fluids as quenching media have low thermal conductivity thus limiting the development of desired microstructure in the steels. The thermal conductivity and stability of nanofluid and hybrid-based nanofluid are studied to enhance the thermal properties of the quenching media.

Milling process is a major machining process used in various type of industries. This process is used to manufacture components such as impellers and structural parts in aerospace industry. Several problems can be arising during the machining operation because 99% of work done produces heat to the chip, the tool and also the workpiece . The temperature of the tool may rise up to 1000oC and this could lead to accelerate the tool wear rate and also the finishing of the surface of the workpiece. In order to improvise this phenomenon, various type of cutting fluid is used in milling operation to use to reduce the temperature of the workpiece. In general, the fluids are used when cutting the workpiece to lower the heat generated at the interface of the tool chip and also the friction on the workpiece. There are four main types of cutting fluid when commonly found in the market which is straight oils, synthetic fluids, soluble oils and the semi-synthetic fluids. This paper is reviewing on the additive for lubricant and their tribology properties.