Techniques, systems, and articles of manufacture for determining the current logical state of a social media communication thread. A first level storage block is used for storing a pointer to a first hash value from among a plurality of hash values. A bearing internal space is divided into a first bearing internal space containing the first ball row and open toward the pinion gear and a second bearing internal space containing the second ball row and sealed by partition walls formed respectively by bearing seals, lubricating grease being sealed in the second bearing internal space. The authentication operation incorporates at least one dynamic component and prompts the user to give an audible utterance.