We utilize a nonlinear, dynamic finite element model coupled with a finite deformation viscoelastic constitutive law to study the inhomogeneous deformation and instabilities resulting from the application of a constant voltage to dielectric elastomers. The constant voltage loading is used to study electrostatically driven creep and the resulting electromechanical instabilities for two different...

Thermoplastics under voltages are used in diverse applications ranging from insulating cables to organic capacitors. Electromechanical instabilities have been proposed as a mechanism that causes electrical breakdown of thermoplastics. However, existing experiments cannot provide direct observations of the instability process, and existing theories for the instabilities generally assume thermopl...

The performance of smart structures depends on the electromechanical behaviour of piezoelectric actuators and the bonding condition along the interface, which connects the actuators and the host structures. This paper provides a theoretical study of the effect of partially debonded adhesive layers on the coupled electromechanical behaviour of piezoelectric actuators subjected to high-frequency ...

We investigated the dependence of electromechanical coupling and the piezoelectric response of a micromachined Pb(Zr₀.₅₂Ti₀.₄₈)O₃ (PZT) diaphragm on its curvature by observing the impedance spectrum and central deflection responses to a small AC voltage. The curvature of the diaphragm was controlled by applying air pressure to its back. We found that a depolarized flat diaphragm does not initia...

Assembling artificial collagenous tissues with structural, functional, and mechanical properties, which mimic natural tissues, is of vital importance for many tissue engineering applications. While the electromechanical properties of collagen are thought to play a role in, e.g., bone formation and remodeling, this functional property has not been adequately addressed in engineered tissues. Here...

background: in neonatal intensive care units (nicu) different sound intensities and frequencies are produced from different sources, which may exert undesirable physiological effects on the infants. the aim of this study was to determine the noise level and its sources in the nicu and neonatal ward of al-zahra hospital of rasht, iran. methods: in this descriptive cross-sectional study, the inte...

BACKGROUND Most antiepileptic drugs (AEDs) inhibit seizure generation by acting on voltage-dependent ion channels. Voltage-dependent sodium and calcium channels are commonly expressed in brain and heart, suggesting that AEDs may have considerable cardiodepressive effects, thereby facilitating sudden cardiac death as a potential cause of sudden unexpected death in epilepsy. Here, we investigated...

OBJECTIVE The aim of this study was to evaluate atrial conduction abnormalities obtained by tissue Doppler imaging (TDI) and electrocardiogram analysis in pregnant subjects. METHODS A total of 30 pregnant subjects (28 ± 4 years) and 30 controls (28 ± 3 years) were included. Systolic and diastolic left ventricular (LV) function was measured using conventional echocardiography and TDI. Inter-at...

BACKGROUND We assessed the validity of the atrial electromechanical interval, measured by transthoracic tissue Doppler echocardiography, in determining patients at risk of post-coronary artery bypass graft atrial fibrillation (AF). METHODS AND RESULTS This prospective study recruited 355 patients in sinus rhythm who were candidates for coronary artery bypass grafting. The patients underwent a...

Electromechanical coupling is a topic of current interest in nanostructures, such as metallic and semiconducting nanowires, for a variety of electronic and energy applications. As a result, the determination of structure-property relations that dictate the electromechanical coupling requires the development of experimental tools to perform accurate metrology. Here, a novel micro-electro-mechani...