Abstract: A system for supporting and carrying bicycles. The system cooperating with the interior surfaces of the seat post engagement tube and includes an adjustable post having a first end and a second end, the first end having an attachment mechanism adapted for connecting the post to a support surface. The second end having at least two generally parallel surface areas at an adjustable distance from one another, so that the distance between the generally parallel areas can be enlarged or reduced in a generally radial manner to create or maintain line contact with the interior surface of the seat post engagement tube.

Abstract: A system for actively damping low frequency noise in an enclosure is provided comprising an acoustic wave sensor, and acoustic wave actuator, and an electronic feedback loop. The acoustic wave actuator is substantially collocated with the acoustic wave sensor within an enclosure. The electronic feedback loop is operative to generate a signal at its output by applying a feedback loop transfer function. The feedback loop transfer function comprises a selected second order differential equation including a first variable representing a predetermined damping coefficient and a second variable representing a tuned natural frequency. The transfer function defines a frequency response having a characteristic maximum gain substantially corresponding to the value of the tuned natural frequency and creates a 90 degree phase lead substantially at the tuned natural frequency. The feedback loop output signal represents a rate of change of volume velocity to be produced by the acoustic wave actuator.