To assess the effects of halothane, isoflurane, and sevoflurane on cross bridges in intact cardiac muscle, electrically stimulated (0.25 Hz, 25 degrees C) right ventricular ferret papillary muscles (n = 14) were subjected to sinusoidal load oscillations (37-182 Hz, 0.2-0.5 mN peak to peak) at the instantaneous self-resonant frequency of the muscle-lever system. At resonance, stiffness is propor...

A frequency domain dynamic analysis is needed to obtain the response of structures constructed on a system of base isolators on flexible soil when subjected to earthquake ground motion. In such systems, the lateral stiffness of the base isolators is so small, compared to the structural stiffness, that in an earthquake attack the fundamental vibration mode dominates the response. With this in mi...

A frequency domain dynamic analysis is needed to obtain the response of structures constructed on a system of base isolators on flexible soil when subjected to earthquake ground motion. In such systems, the lateral stiffness of the base isolators is so small, compared to the structural stiffness, that in an earthquake attack the fundamental vibration mode dominates the response. With this in mi...

This paper describes the experimental studies of vertical dynamic stiffness of single piles subjected to small amplitude of vibrations with constant dynamic load. The test results were correlated with the static load test results that had been carried out on the same piles. The ratio of dynamic to static stiffness mainly falls between 1.2-1.4. The dynamic stiffness measurements were compared wi...

An exact dynamic stiffness method is proposed for the free vibration analysis of multi-body systems consisting flexible beams and rigid bodies. The theory sufficiently general in that bodies can be any shape or size, but importantly, permits connections to number at arbitrary points oriented angles. For beam members, a range theories including Bernoulli-Euler Timoshenko are applied. assembly pr...

Variable stiffness structures that enable a wide range of efficient load-bearing and dexterous activity are ubiquitous in mammalian musculoskeletal systems but are rare in engineered systems because of their complexity, power, and cost. We present a new negative stiffness-based load-bearing structure with dynamically tunable stiffness. Negative stiffness, traditionally used to achieve novel res...

-Stiffness modulation scheme for a robotic driving system with redundant actuation was investigated in this paper. The dynamic and the stiffness models of a simple system having one link and two prismatic actuators were derived and employed for computational simulations of dynamic response to an initial disturbance. Several combinations with different types of elastic elements were applied to t...