Figure 2.

Images of ethylene glycol-based MWCNT nanofluids, after sitting still for 1 week in the laboratory. From left to right: sample 1, pure ethylene glycol; sample 2, ethylene glycol with 0.25 wt% gum arabic; sample 3, ethylene glycol with 0.25 wt% gum arabic and 0.5 wt% MWCNT, no sonication; sample 4, ethylene glycol with 0.25 wt% gum arabic and 0.5 wt% MWCNT, sonicated continuously for 120 min.