Phytochemical Investigation and In Vitro Antimicrobial Activity of Centella asiatica (L.) Urban. A potent Antijaundice medicinal plant

Centella asiatica (L.) is also known as Indian penny wort is a small creeping herbaceous plant belongs to the plant Apiaceae. This plant has been referred in the ancient traditional Indian ayurvedic medicine system about 3000 year’s age. This herb is antidiabetic, antitumor and antidiuretic used in the treatment of jaundice, asthma, bronchitis, dropsy, kidney troubles and leprosy diseases. An investigation was carried out to study the antibacterial activity of Centella asiatica of five different solvent extracts from leaf, stem and roots against selected laboratory bacterial pathogens such as Bacillus subtilis, Staphylococcus aurius, Pseudomonas aurigenosa, Escherichia coli, Klebsiella pnemoniae and Salmonella typhi by agar diffusion method. Zone of inhibition was measured (mm) were compared with standard antibiotics such as kanamycin, cefotoxime, penicillin. The organic solvents such as ethanol, methanol, petroleum ether, chloroform and aqueous extracts were employed. Among all the extracts, methanolic extracts of leaf has showed maximum antibacterial activity against Bacillus subtilis, Salmonella typhi. Phytochemical screening methods were also done to identify the major secondary metabolites in the species such as glycosides, terpenoids, alkaloids, phenolics and tannins. In addition to that the comparative analysis of phenols and tannins of both in conventional plants and in in vitro propagated plants were also traced

Weldability and electrode life determination of resistance spot welding of secondary coated automotive interstitial free steel

<h2>Abstract:</h2><p> </p><p> </p><p>Organosilane is a secondary coating applied over a primary coating of interstitial free (IF) galvannealed (GA) steel. It boosts corrosion resistance and is hence often used in automotive applications. In this investigation, the resistance spot welding of secondary coated GA-IF steel of 0.8 mm thickness has been studied. The effect on the mechanical properties such as: tension & cross tension strength, nugget diameter and the corresponding failure mode because of change in welding current and respective time was evaluated. In this way, the weld lobe was drawn and weldability of weldments were investigated. It has been found that the energy required to weld the nugget increased by 9 % after 1440 number of uninterrupted spot welds with uniformity in the weld nugget. This article also addresses the test protocol for estimating span of the welding electrodes. It has been perceived that, the electrodes can withstand up to 1440 number of uninterrupted welds without affecting the weld quality(in terms of the joint's strength). Nevertheless, the failure mode changes drastically after 600 number of welds due to expulsion during welding. The initial and final stereo images of truncated electrode which was used in this experiment were reported to know the condition of electrode after 1440 number of continuous spot welds and found that the bottom electrode was more eroded than that of top electrode.</p&gt