100000.0f is a magic number... what does it mean? what unit is it in? 

The coding standard explicitly says, no magic numbers.

So, I assume this is something like lifespan in msecs or something... so...

<pre>
const float LIFESPAN_IN_MSECS = 100000.0f;
_particleSystem.setEmitterParticleLifespan(_coolDemoParticleEmitter, LIFESPAN_IN_MSECS);
</pre>