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An attempt was made to drift nanoalumina particles into concrete pores through electrokinetic treatment. An external electric current (current density = 3 A/m2) was applied for 3 and 15 days in reinforced concrete blocks toward steel reinforcement and microstructural characterizations (i.e. morphology observation and porosity analysis) were performed on concrete fragments of different depth from exposure surface. The morphology observation evidenced transport of nanoalumina from the exposure surface even reaching the rebar-concrete interface (up to 25–30 mm, in 15 days treatment). The porosity analysis of treated samples revealed that reduction of porosity of rebar interface was more pronounced as compared to the exposure surface and the treatment for 15 days was more beneficial for porosity refinement than treatment for 3 days. Effects of the electrokinetic NA treatment on strength of rebar-concrete interface were evaluated through pull-out test. The results showed that by increasing current density, bond strength of rebar-concrete interface increased.

The aims of the present study were to develop a dental composite filled with silanized nanoalumina and then to investigate the effect of nanoalumina filler on the two-body and three-body wear behavior under distilled water and food slurry medium, respectively. The dental composites were fabricated by adding silane treated nanoalumina filler particle in the weight percentage of (0–3 wt.%) to the matrix of BisGMA, TEGDMA, CQ and EDMAB. Two-body and three-body wear tests were performed in dental wear simulator machine with varying parameters such as normal load, chewing speed and chamber temperature in such a way as to simulate mastication process. Taguchi’s orthogonal array (L16) design, steady state condition and ANOVA were applied to evaluate the optimum parameter for minimum wear and effect of each parameter on the wear performance of dental composites. The finding of the result indicated that mean volumetric wear rate of dental composite in distilled water (i.e. two-body abrasion) was 33.23% more than that of the same composite in food slurry condition (i.e. three-body abrasion).

Thousands of abandoned wellbores may lie within the aerial extent of a CO2 storage operation. These wellbores represent a potential leakage pathway and a leaky wellbore needs to be re-completed or otherwise repaired to restore seal integrity and ensure containment of the stored CO2. Due to the high cost of recompleting a well, a sufficient economic incentive exists if a viable seal repair technology is available. In this paper, we examine the use of epoxy nanocomposites as potential seal repair materials that have excellent bond characteristics with both steel and cement when cured in the subsurface environment. Test results show Novolac epoxy nanocomposites incorporating nanosilica, nanoclay or nanoalumina to have acceptable flowability that enable injection in wellbore cracks and significantly higher bond strength compared with standard microfine cement.