A combination of an ultrasonic mixing system for preparing an emulsion, a first phase for an emulsion and a second phase for an emulsion, the mixing system comprising: a treatment chamber comprising: an elongate housing having longitudinally opposite ends and an interior space, the housing being generally closed at at least one longitudinal end and having at least a first inlet port for receiving the first phase, a second inlet port for receiving the second phase into the interior space of the housing, and at least one outlet port through which the emulsion is exhausted from the housing following ultrasonic mixing of the first and second phases to form the emulsion, the outlet port being spaced longitudinally from the first and second inlet ports (228, 229) such that the first and second phases flow longitudinally within the interior space of the housing from the inlet ports to the outlet port; and an elongate ultrasonic waveguide assembly extending longitudinally within the interior space of the housing and being operable at a predetermined ultrasonic frequency to ultrasonically energize and mix the first and second phases flowing within the housing, the waveguide assembly comprising an elongate ultrasonic horn disposed at least in part intermediate the first and second inlet ports (228, 229) and the outlet port of the housing and having an outer surface located for contact with the first and second phases flowing within the housing from the first and second inlet ports (228, 229) to the outlet port, and a plurality of discrete agitating members in contact with and extending transversely outward from the outer surface of the horn intermediate the first and second inlet ports (228, 229) and the outlet port in longitudinally spaced relationship with each other, the agitating members and the horn being constructed and arranged for dynamic motion of the agitating members relative to the horn upon ultrasonic vibration of the horn at the predetermined frequency and to operate in an ultrasonic cavitation mode of the agitating members corresponding to the predetermined frequency and the first and second phases being mixed in the chamber, wherein the first phase and second phase are independently selected from the group consisting of an oil phase, a water phase, a silicone phase, a glycol phase, and combinations thereof, and wherein the waveguide assembly is mounted to the chamber housing at an outlet end and extends longitudinally downward within the interior space of the chamber housing. a treatment chamber comprising: an elongate housing having longitudinally opposite ends and an interior space, the housing being generally closed at at least one longitudinal end and having at least a first inlet port for receiving the first phase, a second inlet port for receiving the second phase into the interior space of the housing, and at least one outlet port through which the emulsion is exhausted from the housing following ultrasonic mixing of the first and second phases to form the emulsion, the outlet port being spaced longitudinally from the first and second inlet ports (228, 229) such that the first and second phases flow longitudinally within the interior space of the housing from the inlet ports to the outlet port; and an elongate housing having longitudinally opposite ends and an interior space, the housing being generally closed at at least one longitudinal end and having at least a first inlet port for receiving the first phase, a second inlet port for receiving the second phase into the interior space of the housing, and at least one outlet port through which the emulsion is exhausted from the housing following ultrasonic mixing of the first and second phases to form the emulsion, the outlet port being spaced longitudinally from the first and second inlet ports (228, 229) such that the first and second phases flow longitudinally within the interior space of the housing from the inlet ports to the outlet port; and an elongate ultrasonic waveguide assembly extending longitudinally within the interior space of the housing and being operable at a predetermined ultrasonic frequency to ultrasonically energize and mix the first and second phases flowing within the housing, the waveguide assembly comprising an elongate ultrasonic horn disposed at least in part intermediate the first and second inlet ports (228, 229) and the outlet port of the housing and having an outer surface located for contact with the first and second phases flowing within the housing from the first and second inlet ports (228, 229) to the outlet port, and a plurality of discrete agitating members in contact with and extending transversely outward from the outer surface of the horn intermediate the first and second inlet ports (228, 229) and the outlet port in longitudinally spaced relationship with each other, the agitating members and the horn being constructed and arranged for dynamic motion of the agitating members relative to the horn upon ultrasonic vibration of the horn at the predetermined frequency and to operate in an ultrasonic cavitation mode of the agitating members corresponding to the predetermined frequency and the first and second phases being mixed in the chamber, wherein the first phase and second phase are independently selected from the group consisting of an oil phase, a water phase, a silicone phase, a glycol phase, and combinations thereof, and wherein the waveguide assembly is mounted to the chamber housing at an outlet end and extends longitudinally downward within the interior space of the chamber housing.