background two-dimensional (2d) strain is a new reproducible technique for assessing regional myocardial function; however, its application for evaluation of left atrium (la) function is less studied. objectives we sought to assess la function in heart failure patients using velocity vector imaging (vvi). patients and methods thirty five patients (mean age: 43.34 ± 18.1 years, 59.3% male) with ...

pH-responsive hydrogels are capable of converting chemical energy to mechanical work. To optimize their use as actuators, their response when operating against an external load must be fully characterized. Here, the actuation strain of a model pH-sensitive hydrogel as a function of different constant loads is studied. The experimental actuation strain, produced by switching the pH from 2 to 12,...

The stiffness of the workpiece is very important to reduce the errors in manufacturing process. The high stiffness of the workpiece can be achieved by optimal positioning of fixture elements in the fixture. The minimization of the sum of the nodal deflection normal to the surface is used as objective function in previous research. The deflection in other direction has been neglected. The 32-1 f...

in this paper, the mean value of strain energy density criterion has been used to predict the critical fracture load in specimens with u-shaped notch under bending loads. an equation for calculation of averaged strain energy density in this zone has been presented. bending loads under mode i have been considered. two cases have been studied: 1) the control volume only includes the semicircular ...

We develop a thermodynamic framework for modeling nonlinear ultrasonic damage sensing and prognosis in materials undergoing progressive damage. The framework is based on the internal variable approach and relies on the construction of a pseudo-elastic strain energy function that captures the energetics associated with the damage progression. The pseudo-elastic strain energy function is composed...

In this article, an efficient methodology is presented to optimize the topology of structural systems under transient loads. Equivalent static loads concept is used to deal with transient loads and to solve an alternate quasi-static optimization problem. The maximum strain energy of the structure under the transient load during the loading interval is used as objective function. The objective f...