Current research and development status of corrosion behavior of automotive materials in biofuels

The world’s need for energy is increasing with the passage of time and the substantial energy demand of the world is met by fossil fuels. Biodiesel has been considered as a replacement for fossil fuels in automotive engines. Biodiesels are advantageous because they provide energy security, they are nontoxic, renewable, economical, and biodegradable and clean sources of energy. However, there are certain disadvantages of biodiesels, including their corrosive, hygroscopic and oxidative natures. This paper provides a review of automotive materials when coming into contact with biodiesel blended fuel in terms of corrosion. Biodiesels have generally been proved to be corrosive, therefore it is important to understand the limits and extents of corrosion on different materials. Methods generally used to find and calculate corrosion have also been discussed in this paper. The reasons for the occurrence of corrosion and the subsequent problems because of corrosion have been presented. Biodiesel production can be carried out by different feedstocks and the studies which have been carried out on these biodiesels have been reviewed in this paper. A certain number of compounds form on the surface of materials because of corrosion and the mechanism behind the formation of these compounds along with the characterization techniques generally used is reviewed

Wear characteristics of patterned and un-patterned tetrahedral amorphous carbon film in the presence of synthetic and bio based lubricants

In this article, wear performance of patterned and non-patterned tetrahedral carbon thin film (ta-C) is compared in the presence of various lubricants. For this purpose, wear tests were conducted at temperatures (40 °C-125 °C) which are normally found during automotive engine operation. Wear test were conducted at 100 N load and 120 min. The results showed that bio-based lubricant show better wear performance at 40 and 80 °C compared to PAO lubricant for both laser patterned and non-patterned ta-C thin film. However, at the temperature of 125 °C, PAO showed better wear performance than palm based TMP ester. This can be because of unstable film formation at higher temperatures in case of bio-based lubricant. It was also found that patterned ta-C thin films shows higher wear resistance than non-patterned thin film. This can be because of micro pores which can provide lubricant, capture micro and nano wear particle and behave as micro hydrodynamic bearings

Continental-scale temperature variability during the past two millennia

Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the nineteenth century. At multi-decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between ad 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century. The transition to these colder conditions occurred earlier in the Arctic, Europe and Asia than in North America or the Southern Hemisphere regions. Recent warming reversed the long-term cooling; during the period ad 1971–2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years