The dynamic mechanical behavior of excised rabbit papillary muscles that had been tonically activated by replacing bathing Ca2+ with Ba2+ was studied. Steady activation was used to visualize the dynamic behavior of cardiac myofilaments more clearly than is possible during twitches, which are complicated by the kinetics of excitation-contraction coupling. To avoid artifacts due to damaged ends o...

This masonry research investigated the differences in the static and dynamic stiffness for the seismic range of loads and frequencies for a pressed clay masonry wythe. The effective stiffness has been defined in Newtonian physics and Damage Mechanics. This research used the concept of measured stiffness defined as the measured stress field divided by the measured strain field. A two-part test r...

The study of rock fractures is essential in evaluating stability of underground structures, understanding earthquakes, and assessing storage and transport of oil and gas in rock formations. Geophysical monitoring techniques, particularly compressional and shear wave propagation, can probe the internal structure of rock and fractures remotely and nondestructively and can provide insight into fra...

Flexible pins eliminate the need for straddle mounting, and therefore enable the maximum possible number of planets to be used for any particular epicyclic ratio of power transmission systems. Having more planet gears will significantly increase the input torque density. In this type of design, the pin stiffness and position tolerances are important parameters as they affect the dynamic perform...

this study presents a new approach to control the nonlinear dynamics of an adaptive absorber using shape memory alloy (sma) element. shape memory alloys are classified as smart materials that can remember their original shape after deformation. stress and temperature-induced phase transformations are two typical behaviors of shape memory alloys. changing the stiffness associated with phase tran...

A chicken egg is an already packaged food. An important quality aspect of the packaging material is the mechanical strength of the eggshell. A commonly used technique for the measurement of the shell strength is the quasi-static, non-destructive compression of an egg between two parallel steel plates. The slope of the force-deformation curve is a measure for the stiffness of the shell and for t...

Forced vibration analysis of plate is growing research subject as plates are used for manufacturing many mechanical structures. The analytical solutions have been found for plates with specified mass and stiffness but for the plates with uncertain mass and stiffness are studied very limitedly. The uncertain parameters play an important role in the design of practical mechanical system. It becom...

A nonlinear coupled dynamic model of a rod fastening rotor under rub-impact and initial permanent deflection was developed in this paper. The governing motion equation was derived by the D’Alembert principle considering the contact characteristic between disks, nonlinear oil-film force, rub-impact force, unbalance mass, etc. The contact effects between disks was modeled as a flexural spring wit...

optimal balancing is a new approach based on optimal control a which modes, controls and the amount of equilibrium scale are calculated simultaneously. this approach has a significant effect on increasing performance of industrial robots which causes maximum decreasing of energy consumption. despite many applications of robotics such as welding and gluing, the path is predefined , but other unk...