The combined effect of Brownian diffusion and thermophoretic (collision between molecules of base fluid and nanoparticles) on the onset of convection in a rectangular box has been investigated in the present paper. Convective boundary condition and modified mass flux condition are considered. Darcy model is used for porous media. The linear stability of nanofluid is analysed by calculating the critical Rayleigh number using normal mode technique and resulting equations are solved by the Galerkin residual method It is also found that effect of nanoparticles on convection is independent to the aspect ratio of a rectangular box. The stabilising/destabilising effects of various governing parameters on the convection have also been presented graphically.The influence of different fuel/nitrate molar ratios on the characteristic of precursor nanocomposites was also analysed. It has been observed that the presence of monoclinic phase decreases with increase of fuel ratio used in the combustion process.
This study is to evaluate the potential of Parthenium hysterophorus leaf extracts for the synthesis of nanoscale zerovalent iron (nZVI) and their chromium remediation property. Due its high toxicity and mobility, hexavalent chromium is considered to be a high priority pollutant. In addition this work was executed to carry out toxicity appraisal in a water sample collected from Puliyanthangal Lake, Tamilnadu, India using nZVI. The water samples were examined before and after the nZVI application by means of microbial cultivation tests, phospholipid fatty acid analysis (PLFA) and toxicological tests. The present experimental results revealed that Cr (VI) is considerably adsorbed on nZVI nanoparticles and it could be a cost effective method for the in situ remediation of Cr (VI). In addition, standard plate count assay showed the dose dependent decrease in the bacterial cell viability in lake water sample after the addition of nZVI.