BIOREDUCTION OF SILVER NANOPARTICLES FROM AQUEOUS STEM EXTRACT OF CATHARANTHUS ROSEUS AND BACTERICIDAL EFFECTS.

Objective: Silver nanoparticles (AgNPs) were synthesized using the stem extract of the Catharanthus roseus (L.) plant using the green method. Theextract from the stem of C. roseus plant was obtained using standard dry powder extraction method. The colorless silver nitrate solution was changedinto brown color after the addition of stem extract indicates the formation of AgNPs. The chemical compounds present in the stem extract wereacting as a reducing agent for the synthesis of AgNPs. Methods: The AgNPs were analyzed with the help of UV-visible spectrophotometer for initialconfirmation. Fourier transform infra-red spectroscopy (FT-IR) confirmed the presence of various phytochemicals such as carbohydrate, phenoliccompounds, flavonoids, saponin. and alkaloids which were responsible for both reduction and stabilizing the action of the silver nanoparticles.Results: From the transmission electron microscopy analysis, it was confirmed that Ag-nanoparticles are in nanosize range between 40-50nm andare mono dispersed of particle distribution. Conclusion: From the zone of inhibition, it was confirmed that the synthesized Ag NP from the C. roseusstem was found to have a very high antimicrobial effect. From this study, it is clear that the AgNp can be used as a potential antimicrobial agent.Keywords: Catharanthus roseus, Silver nanoparticles, Anti-microbial activities

Effect of processing parameters on the morphology of the interfacial intermetallics between Cu and SnPb solders

The wetting reaction between Cu substrate and the molten Sn-Pb solder alloys of four different compositions had been studied to characterise the morphology of the intermetallic compound (IMC) at the interface between Cu and solder. The morphological changes of the IMC layer is analysed with respect to the Pb-content of the solder alloy, molten solder temperature (10°C, 20°C, 40°C and 60°C above the liquidus temperature of each alloy) and immersion time of Cu. The morphology of the IMC is classified into three broad groups namely, cellular, scallop and planar. These morphologies are found to vary gradually from one type to the other with the Pb-content, temperature and time. Fractal Dimension (FD), a measure of roughness, is estimated from the digitized SEM micrographs of the IMC layer at each reaction condition and it is correlated with reaction conditions

Data set for extraction and transesterification of bio-oil from Stoechospermum marginatum, a brown marine algae

The article presents the experimental data on the extraction and transesterification of bio-oil derived from Stoechospermum marginatum, a brown macro marine algae. The samples were collected from Mandapam region, Gulf of Mannar, Tamil Nadu, India. The bio-oil was extracted using Soxhlet technique with a lipid extraction efficiency of 24.4%. Single stage transesterification was adopted due to lower free fatty acid content. The yield of biodiesel was optimized by varying the process parameters. The obtained data showed the optimum process parameters as reaction time 90 min, reaction temperature 65 °C, catalyst concentration 0.50 g and 8:1 M ratio. Furthermore, the data pertaining to the physio-chemical properties of the derived algal biodiesel were also presented