SensorML and HUML in Situation Awareness Processing for Autonomous Mobile Sensor Networks.

An agitator of impeller shape includes an agitator hub with a plurality of radially extending arms for attachment to a drive shaft for the mixing of substances in vessels, such as substances that tend to material build-up, incrustation and/or incipient polymerization. The hub is totally closed by welding a cap over the end of the hub. At least one of the agitator arms is formed of two components, a shorter stub arm attached to the hub and longer main arm. Both components are formed of a pair of parallel, spaced apart tubes connected by a pair of webs. Each tube includes a bushing for retaining a centering bolt to attach the main portion to the stub portion. The two components are then welded together and polished to remove any gaps and sharp edges.