Search

The ability to predict the weathering performance of the clearcoat system over a short period of time is essential for the design and development of coating production. Thus, the primary objective of the present study is to investigate whether it is possible to predict the weathering performance of an automotive paint system through determination of surface roughness, Ra, and micro-hardness before and after various weathering exposure times (0, 24, 168, 336, 504, 672 hours) and when employing two different detergent materials (house-use detergent and car wash detergent). The data were analysed using a pair-sample t-Test, with 0.05 level of significance. It was found that the total net of degradation in the clearcoat level during the first 24 hours was Ra ≈ 30.3 nm (for surface roughness) and 1.358 HV (for the μ-hardness) when using the house-use detergent. In contrast, it was found to be Ra ≈ 4.6 nm (for surface roughness) and 1.133 HV (for μ-hardness) when using the car wash detergent. Also, increased time of weathering (up to 672 hours) increases the Ra and μ-hardness values. It can therefore be concluded that the effect of house-use detergent was more severe than that of car wash detergent on the clearcoat system.

Understanding the effects of enamel loss and surface softening caused by acidic soft drinks consumption would help in the clinical treatment of tooth wear and aid in the development of novel dental restorative materials. Hence, this investigation was car-ried out to examine the effects of “Miswak” on the acid eroded enamel surface at nano-mechanical scale. The first use of a stylus-based inductive gauge is introduced as means of measurement of acid attack on enamel surfaces and the effectiveness of aqueous extracts of Salvadora persica as dissolution inhibitors for acid eroded enamel surfaces. For pre-molar protective, after being exposed to aqueous extracts of Salva-dora persica solution, the performance of the enamel surface was improved by Ra ≈ 0.82 μm. Whereas, the surface was damaged after immersing in citric acid solution by Ra ≈ 0.63 μm. For pre-molar restoring, the enamel surface was degraded by Ra ≈ 0.34 μm when exposed to citric acid solution. While, the surface roughness was improved by Ra ≈ 0.95 μm when aqueous extracts of Salvadora persica solution was introduced. So, this study concludes that the aqueous extracts of Salvadora persica treatment work effectively on the eroded enamel surface.