No abstract

No abstract

Effect of nanosilica size on physic-mechanical properties, thermal stability and weathering durability of coating based on acrylic emulsion. Nanocomposite coating formulas were filled by 2 wt.% nanosilica particles which were used in this study, namely: nanosilica from Sigma (15-20nm), nansilica from rice husk (~70-200 nm) and nanosilica from Arosil – Belgium (7-12 nm). Obtained results showed that viscosity flow of coating formula containing nanosilica from Arosil saw the highest flow-time while coating formulas filled other nanosilica and unfilled nanosilica experienced similar flow-time. In presence of nanosilica, coating properties were improved in comparison with neat coating. However, coating filled by nanosilica from rice husk indicated the best properties in studied coating formula. It may explained that size of nanosilica from rice husk was the largest in studied nanosilica particles and thus easily dispersing into coating formula.

In this study, we propose an approach using the gamma transmission technique based on the combination of the experimental and simulated data for determining the percentage concentration of the acid solution. The experiment consists of a collimated 137Cs radioactive source emitting a narrow gamma beam of 662 keV and a NaI(Tl) detector. Monte Carlo simulation data is used to construct the calibration curve of lnR versus the percentage concentration of acid solution at different temperatures (R is the ratio of the area under a transmission peak for an acid solution relative to that for water). The percentage concentration of the acid solution is determined based on the calibration curve and the experimental ratio R. The obtained results showed that this approach was feasible in which the percent concentration of 7 in total 8 samples of the sulfuric acid solution are less than 5% in comparison with one of the reference samples. There is only one sample with a relative deviation of 7.6%. These preliminary results suggest that it is possible to develop nondestructive testing for the rapid determination of the percentage concentration of acid solutions based on the gamma transmission technique.