Safe Experimentation in Optical Levitation of Charged Droplets Using Remote Labs.

The work presents an experiment that allows the study of many fundamental physical processes, such as photon pressure, diffraction of light or the motion of charged particles in electrical fields. In this experiment, a focused laser beam pointing upwards levitate liquid droplets. The droplets are levitated by the photon pressure of the focused laser beam which balances the gravitational force.

Axial stiffness of human lumbar motion segments, force dependence.

This paper addresses the axial stiffness of human lumbar motion segments while subjected to moderate loads. Impacts in axial direction were applied to Functional Spinal Units while they were subjected to weights acting as static pre-load. Accelerations were recorded proximal and distal of the FSU.

In vivo dynamic stiffness of the porcine lumbar spine exposed to cyclic loading: influence of load and degeneration.

The dynamic axial stiffness of the L2-3 motion segment subjected to vibratory loading under intact and injured states of the intervertebral disc was studied using an in vivo porcine model. Three groups of animals with the following states of the intervertebral discs were studied: intact disc, acutely injured disc, and degenerated disc. A miniaturized servo-hydraulic exciter was used to sinusoidally vibrate the motion segment from 0.

Intervertebral disc response to cyclic loading--an animal model.

The viscoelastic response of a lumbar motion segment loaded in cyclic compression was studied in an in vivo porcine model (N = 7). Using surgical techniques, a miniaturized servohydraulic exciter was attached to the L2-L3 motion segment via pedicle fixation. A dynamic loading scheme was implemented, which consisted of one hour of sinusoidal vibration at 5 Hz, 50 N peak load, followed by one hour of restitution at zero load and one hour of sinusoidal vibration at 5 Hz, 100 N peak load.

Resonant frequency of a pin-accelerometer system mounted in bone.

Invasive measurements of spinal motion using intraosseous metal pins have become common. For this reason, the resonant frequency of intraosseous pins attached with accelerometers was determined using two different methods. It was concluded that plucking the pin is a reliable method for determining the resonant frequency and, in order to accurately measure bone movement at frequencies up to 32 Hz, the pin diameter should be 2.

Effect of backrest inclination on the transmission of vertical vibrations through the lumbar spine.

Unlabelled: Various studies have demonstrated a positive relationship between low back pain and driving of vehicles. Little work has been done to establish how posture or seat design can attenuate vibrations. By means of skeletally mounted accelerometers it was demonstrated that the inclination of the backrest has only a minor role in vibration attenuation in the 4-6 Hz range.