The tribological characteristics of sliding surfaces have been remarkably improved by surface texturing. Surface texturing can be beneficial in many ways; for example, it can reduce friction and wear, increase load carrying capacity, and increase fluid film stiffness. The design process for surface texturing is highly correlated to the particular functions of any application for which texturing is required. Texture quality is greatly affected by manufacturing methods, therefore, it is important to have a detailed understanding of the related parameters of any technique. The use of surface texturing to improve the cutting performance of tools is a relatively new application. These textures improve cutting performance by enhancing lubricant availability at the contact point, reducing the tool-chip contact area, and trapping wear debris. Reductions in crater and flank wear, friction force, cutting forces, and cutting temperature are the main benefits obtained by this technique. To date, surface texturing has been successfully used in drilling, milling, and turning operations. This article provides an overview of the techniques that have been used in industry and research platforms to manufacture micro-/nano-textures for tribological applications, and it examines the effects of surface textures on cutting tool performance.

Biodiesel, which comprises fatty acid esters, is derived from different sources, such as vegetable oils from palm, sunflower, soybean, canola, Jatropha, and cottonseed sources, animal fats, and waste cooking oil. Biodiesel is considered as an alternative fuel for diesel engines. However, biodiesel has poor cold flow behavior (i.e., high cloud point & pour point) and oxidation stability compared with petroleum diesel because of the presence of saturated and unsaturated fatty acid esters. Consequently, the performance of biodiesel during cold weather is affected. When biodiesel is oxidized, the subsequent dregs can adversely affect the performance of the fuel system as well as clog the fuel filter, fuel lines, and injector. This phenomenon results in start-up and operability problems. Cold flow behavior is usually assessed through the pour point (PP), cloud point (CP), and cold filter plugging point (CFPP). Earlier studies on cold flow focused on reducing the devastating effect of poor cold flow problems, such as lowering the PP, CP, and CFPP of biodiesel. This present paper provides an overview of the cold flow behavior and oxidation stability of biodiesel, as well as their effect on the engine operation system. The improvements on the behavior of cold flow of biodiesel are also discussed.

The increasing use of bioethanol causes tribological effects on engine components. It is crucial to study the effect of bioethanol on oil degradation and friction and wear behaviors of engine oil, using four-ball wear tester.