On the kinematics of the head using linear acceleration measurements.
Abstract The paper deals with an application of the nine accelerometer scheme proposed by Padgaonkar et al. (1975) to the analysis of the head kinematics including the head angular acceleration and velocity using linear acceleration measurements. The computed results have been compared with the film analysis and with the actual measured quantities in the case of the dummy experiments. The study reveals an excellent agreement among these results and indicates the feasibility of the application of the method to biomechanical studies.
Low frequency self-generated vibration during ambulation in normal men.
An assessment was made of the upper body low frequency steady-state vibration in five normal male subjects during level walking in a straight line. Speed of progression ranged from 0.99 to 2.35 m/s. Through a stereophotogrammetric technique, a three-dimensional measurement of the linear displacement of the longitudinal axis of the trunk and head was done. The relevant accelerations were obtained by double differentiation and described both in the time and frequency domains. The data were compared with those available on the biodynamic properties of body tissues and on the subjective response of humans to externally generated whole-body vibration. The comparison yielded a consistent indication of the characteristics of the vibration stimulus to which the human body may be adapted. As walking speed approached its maximum, the vertical acceleration spectrum increased in magnitude and shifted critically close to frequencies at which body organs are known to undergo resonance. A coordinated movement of the trunk with respect to the pelvis helped to reduce to a minimum the value of the acceleration to which the head was submitted in the antero-posterior direction and to shift the relevant spectrum towards the lower frequencies.
Investigations of dielectric gratings using electrodynamic models based on volume integral equations
Eigenmodes of planar and cylindrical dielectric gratings (DGs) and electromagnetic wave scattering from multiplayer DGs are investigated. The DG characteristics are calculated using numerical-analytical solution of integral equations (IEs).