Abstract: An earring force tester for clip-on type earrings detects the spring force of an earring and provides a visual output signal including whether the spring force is above (too tight), below (too loose) or within an acceptable range of force. The output signals are different colored LEDs. The lower and upper boundaries of the range can be adjusted such as to calibrate the device.

Abstract: An apparatus for positioning a human subject on a surface and for transferring a subject from one surface to another. The subject is situated on the top surface of a fluid enclosure and an actuator mechanism causes local deformations of the top surface in such a manner as to create traveling waves whereby a force tangential to the top surface is exerted on the subject for moving the subject with respect to the surface. The actuator mechanism may be a motor driver and may be a plurality of linear actuators configured so as to cause local deformations of the top surface in a direction having a vertical and/or horizontal component. The linear actuators may be shape memory fibers.