A Parallel Round-Robin Arbiter system and method for arbitrating among N requesters. The bicycle hub comprises two flanges which are located at end sections of the hub. The flowmeter is able to self-generate current responsive to the flow of the fluid therethrough. Further, the pad may also be used to maintain probe tips in a desired operating shape. The additive compositions contain at least one water-soluble film-forming polymer; optionally, at least one pH regulating agent capable of maintaining the pH value of an aqueous solution at about 7 or below; and at least one compound selected from the group consisting of phosphonic acid derivatives of formula I.