The present study describes the biocorrosion of mild steel (MS1010) and pure copper (Cu) in cooling water environments (both field and lab study). Electrochemical and surface analyses of both metals were carried out to confirm the corrosion susceptibility in the presence of bacteria and inhibitor. Surface analysis of the MS and Cu coupons revealed that biofilm was developed with increasing exposure time in the field study. In the lab study, accumulation of extracellular polymeric substance over the metal surface was noticed and led to the severe pitting type of corrosion on both metal surfaces. Besides, the anti-corrosive study was carried out using the combinations of commercial corrosion inhibitor (S7653-10 ppm) with biocide (F5100-5 ppm), and the results reveal that the corrosion rate of MS and Cu was highly reduced to 0.0281 and 0.0021 mm/year (inhibitor system) than 0.1589 and 0.0177 mm/year (control system). Inhibition efficiency for both metals in the presence of inhibitor with biocide was found as 82 and 88% for MS and Cu, respectively. The present study concluded that MS was very susceptible to biocorrosion, compared to copper metal in cooling water environment. Further, the combination of the both inhibitor and biocide was effectively inhibiting the biocorrosion which was due to its antibacterial and anti-corrosive properties.

The CaO:xDy3+, yNa+ phosphors, were synthesized by high solidstate method, and the starting materials are CaCO3Na2CO3 and Dy2O3. The effects of the Dy3+,Na+doping concentration on luminescent properties were studied by TG/DSC,XRD and PL spectra.The results indicated that when the sinter temperature of precursors over 950 °C,the main phase of the phosphor is CaO, and when x=0.02,y=0.15 we obtained the best luminescent properties of CaO:xDy3+, yNa+phosphors;Na+effectively enhances the luminescent properties of phosphors;The maximum emission wavelength is about 480 nm (blue),corresponding to 4F9 /26H15 /2 of Dy3+; There are a series of spectral lines in the 240-420 nm range of excitation spectrum,and the strong excitation peak located at 360 and 375 nm.