When the original used oil sample was observed under light microscope, a welldispersed
water-in-oil emulsifying state was clearly seen. Oil immersion technique and
both regular/polarized light modes were used to focus beyond the cover slide and prevent
the interference from trapped air bubbles. Since used oil must have certain levels of
surfactants carried from its additive package, it seems that a good emulsion is naturally
formed without further addition of surfactants. After extra water was added into used oil
and mechanically mixed by the blender, the emulsion sample was also observed under
light microscope. Finer and more homogeneously dispersed vesicles were observed.
Emulsion samples were prepared with different selections of speed and time. The
stability of the emulsion was checked by microscopic examination. However, the size of
the vesicles is not measured at this time due to instrumental unavailability but will be
determined for comparison later. An optimal speed/time combination will be decided for
preparation of future samples.