Tribological evaluation of solid lubricant enriched in modified Jatropha-Based Oil as Minimum Quantity Lubrication (MQL) oil for composite material

The use of lubricant during the machining process plays an important role to reduce friction and wear. Mineral-based oil is the most widely used lubricant that provided high-quality lubrication properties. However, mineral-based oil has poor biodegradability and causes long-term pollution to the environment and harmful to human. Implementation of environmental-friendly lubricant was encouraged to achieve sustainable manufacturing practices. The inherent biodegradability of vegetable-based oil with solid particle offers greater benefit to the environment and lubrication performance. The study aims to evaluate the influence of green solid particle (hexagonal boron nitride, hBN) enriched in the modified jatropha oil (MJO) through tribology testing using four-ball tribotestermachine. hBN particlewas added inMJOat various concentration ratio; 0.05wt% and 0.5wt%. TheMJOsamples were compared with the crude jatropha oil and commercial synthetic ester. The tribology testing was conducted according to ASTM D4712. The value of coefficient of friction, wear scar diameter, worn surface analysis and surface roughness were evaluated. The lowest concentration of hBN particles in MJO (MJO + 0.05 wt% hBN) has reduced the coefficient of friction with smaller wear scar diameter and better surface roughness quality. The worn surface analysis from the ball lubricate byMJO + 0.05 wt% hBN had light and shallow grooves. The study proved that MJO + 0.05 wt% hBN exhibits better lubrication ability and suitable as an alternative for the environmental-friendly lubricant especially for minimum quantity lubrication (MQL) oil

Tool life improvement in cryogenic cooled milling of the preheated Ti-6Al-4V

Cryogenic-based machining has been drawing attention for machining hard metals and super alloys such as the titanium alloys due to environmental concerns and growing regulations over pollution. In this study, cryogenic-assisted milling of Ti-6Al-4V has been performed with the preheated workpiece methods to avoid the cryogenic hardening by liquid nitrogen (LN2). Preliminary experiments show an increase in the cutting force due to cooling of the workpiece; therefore, workpiece preheating was adopted to increase the workpiece temperature. Three cutting speeds and three machining environments (dry, cryogenic, and cryogenic plus preheated) were considered in the analysis of tool wear, cutting forces, tool wear morphology, and chip morphology. Soft (Si coating) and hard (CrTiAlN)-coated tools were used in this study. It was observed that the tool life was increased by 50 to 90 % for Si-coated tools and 50 to 55 % for CrTiAlN-coated tools. The tool wear morphology showed that rubbing and chipping were the primary tool wear mechanisms. It is expected that the present work will be useful for improving tool life and reducing the cost of hard metal products. It may also be useful for reducing the ecological problems by conventional cutting fluids.close0

Electrical Conductivity of Alkali-silicate Glass containing Fe_2O_3.

Electrical resistivity (ρ) of Alkali-Silicate glasses has been measured to find out the behavior of Fe-ion in these glasses. ρ depends mainly upon the Fe^<2＋>/Fe total-ratio, and has the minimum peak. The behavior of Fe-ion at the minimum of ρ is discussed by the results of Mo^^¨ssbauer-spectra in terms of the oxygen-coordination number of Fe^<3＋>-ion. The mechanism of electrical conductance in these glasses is assumed to be the valence electron transfer between Fe^<2＋> and 6-fold oxygen Fe^<3＋>

Biolubricants and the potential of waste cooking oil

In the current decade, development of recycle, renewable, and sustainable products to replace fossil products is an essential and important matter from industrial,environment, and academic point of views. The excessive usage of Petroleum-based oils significantly contributes to the pollution of the environment and had caused environmental pollution and awareness from the environmental sectors. Researchers start exploring an alternative oil from natural resource aiming to replace the fossil oil and this becomes the main ambitious of many researchers, environmental, and government bodies. In this chapter, a comprehensive literature review is introduced and several issues are addressed with regards of the usage of newly developed lubricants that are based on vegetable oils. Furthermore, it is exploring the potential of using waste cooking oil as lubricant for tribological applications