A bucket tooth capable of preventing a bolt from being loosened during operation is provided. The string further including a plurality of sensors joined to the communication line between the ends and each sensor being mounted at a set position on the line. A tri-partied partitioning scheme can be used wherein the computer executable instructions of the software TPM reside in a first region, a jump table to appropriate ones of those instructions resides in a second region, and everything else resides in the third region. The passage between the edges of the fan blades and the working air fan cover has been widened and made uniform to aid in the passage of debris over the top of the working air fan.