Castor (Ricinus communis) beans were subjected for the extraction of oil which contained 48% yield. The refined oil contained 0.8% free fatty acid (FFA) and 76.258mg KOH/g saponification value which showed that oil was very suitable for biodiesel production. Biodiesel can be synthesized by transesterification process using acid or base catalyst. The obtained oil and biodiesel was analysed by GC/MS and characterized for its use as fuel in compression ignition motors. From GC/MS, methyl esters content (6:1 molar ratio) was found to be about 88%. The experiments were performed at variable condition such as methanol/oil molar ratio, different temperatures, types and   concentration of catalysts used. The best condition for transesterification process was 9:1 methanol/oil molar ratio, 65°C and 1 weight % of KOH. Product analysis was performed by ASTM/EN standards. The obtained biodiesel provided satisfactory values of density and saponification but its viscosity was very high. This situation can be corrected by mixing other methyl esters or mineral diesel for its use as diesel fuel.DOI: http://dx.doi.org/10.3126/njst.v15i1.12009 Nepal Journal of Science and TechnologyVol. 15, No.1 (2014) 45-52

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Antibacterial activity of different extracts of heartwood of Acacia catechu were tested against 11 species of bacteria and antifungal activity were tested against four species of fungi. Among bacteria species highest zone of inhibition (ZOI) was measured against Pseudomonas species by diethyl ether extract, likewise among fungal organism highest zone of inhibition (ZOI) was measured against Fusarium oxysporim by ethyl acetate extract. No extracts showed activity against Salmonella typhi, Salmonella paratyphi, Escherichia coli and Proteus mirabilis. The minimum bactericidal concentration (MBC) of ethyl acetate extract was evaluated against Bacillus subtilis, Klebsiella pneumonia, Staphylococus aureus and Shigella species.DOI: http://dx.doi.org/10.3126/jncs.v27i1.6667 J. Nepal Chem. Soc., Vol. 27, 2011 94-99

Antibacterial activities of different extracts of epiphytic orchids were tested against 5 species of bacteria and antifungal activities were tested against 3 species of fungi. All orchid extracts showed good bacterial Zone of Inhibition (ZOI) against Staphylococcus aureus. The crude extracts of Pholidota imbricata and Coelogyne cristata were shown highest activity against Vibrio cholerae and Staphylococcus aureus respectively. The MIC and MBC value of the extracts of Pholidota imbricata and Coelogyne cristata were found to be 62.5 mg/ml, 31.25 mg/ml and 125 mg/ml, 250 mg/ml against Vibrio cholerae and Staphylococcus aureus respectively. Only Pholidota imbricata and Pholidota articulata extracts were shown fairly good activity but all others extracts were shown very less activity or even failed to show any activity against fungal organisms.DOI: http://dx.doi.org/10.3126/jncs.v29i0.9259Journal of Nepal Chemical Society Vol. 29, 2012 Page: 104-109 Uploaded date: 12/5/2013

Effects of Nepal origin plant species of Vitex negundo, Catharanthus roseu, Aegle marmelos and Elaeocarpus ganitrus extracts on mild steel corrosion were explored in bioethanol (E100) and its blend (E15) in airtight condition at 25±2 °C using static immersion, inhibition efficiency and mechanism tests which were complemented with adsorption isotherms and potentiodynamic polarization studies. Corrosion resistance of the mild steel was increased with increasing 500-2000 ppm concentrations of each plant extract in E100 and E15 biofuels. Additions of V. negundo and C. roseus extract separately in both the biofuels seems to be more effective inhibition actions to prevent the mild steel corrosion than A. marmelos or E. ganitrus addition so as the corrosion rates of the mild steel in E100 and E15 are successfully lowered even than in commercial gasoline (E0). The results obtained from the corrosion rate revealed the order of the corrosion inhibition efficiency (IE) as V. negundo > C. roseus > A. marmelos > E. ganitrus. The maximum IE (IEmax) in V. negundo and C. roseus leaves was showed about 89-86% and 71-75%, respectively, at 2000 ppm concentration, in spite of the other two more plants leaf extract also used as the corrosion inhibitors for the mild steel in both E100 and E15 biofuels. The IE increased on increasing inhibitor concentration following the Langmuir and Temkin adsorption isotherms but decreased with immersion time which suggested that the corrosion inhibition mechanism is of physical type of adsorption of the leaves constituents on the mild steel surface. A. marmelos extract acted as an anodic type of inhibitor in E100 and E15, while E. ganitrus acted as mixed