In this study, an attempt was made to optimize the conditions for the transesterification of sunflower oil with methanol, catalyzed by Ca-K/Al2O3 nanocatalysts, using response surface methodology. The examined variables were reaction temperature (55, 65 and 75 °C), reaction time (1, 2, 3, 4 and 5 h), catalyst weight base oil (3, 6, 9 and 12 wt%), Ca content (20, 30, 50, 60 and 80 wt%), K content (5, 10, 15 and 20), methanol:sunflower oil molar ratio (3:1, 6:1, 9:1 and 12:1), calcination temperature (600, 700 and 800 °C) and calcination time (1, 2, 3 and 4 h). Catalyst characterization was done by X -ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR) and temperature programmed desorption (TPD). The maximum fatty acid methyl esters (FAME) conversion efficiency (biodiesel production efficiency) was 98.3%, at a calcination temperature of 800 °C for 3 h, a methanol-to-oil ratio of 9:1, a reaction temperature of 75 °C, a reaction time of 3 h and a catalyst-to-oil mass ratio of 9%.

Ancient Iranian silver coins minted in various parts of the ancient Iran from Transoxiana to Mesopotamia over a time span of 460 years (247BC-208AD) during Parthians dynasty were analysed by PIXE with a 2.2 MeV proton beam. Forty seven silver coins owned by Tamashagah-e-Pool (museum of money) in Tehran were examined in this study. The possible correlation between the composition of coins and the minting time or the minting location of coins has been the prime objective of the present study. Elemental analysis of ancient coins could also reveal the direct relation with the political and economical situation and also with the metallurgy of the minting time. Results on the contents of principal component elements ( Fe , Ni , Cu , As , Br , Ag , Sn , Sb , Ba , Au and Pb ) are presented and discussed.