It was thought previously that cardiac muscle gap junctions provide low-resistance connections between cells and permit the local-circuit current to flow. Some evidences show that myocardial cells may not require low-resistance connections for successful propagation of the action potential (AP). It seems that some other types of mechanisms must be involved in AP propagation. In this article, we...

The thesis presents a combined experimental and computational investigation of a novel thermochemical material removal mechanism for cutting of polycrystalline cubic boron nitride (PCBN) substrates through controlled crack propagation. The CO2-Laser/Waterjet machining system developed by the Iowa State University’s Laboratory for Lasers, MEMS, and Nanotechnology was utilized to achieve specimen...

ABSRACT: Reports of collapses and whumpfing sounds and their links to instability in the snowpack have been around for decades, but like many areas of snow science, they have received limited scientific treatment. There is a consensus that shear fracture plays an important role in the avalanche process, but the role of collapse is disputed. Many field and laboratory measurements show support fo...

In this study, application relevant toughened epoxy-amine formulations were investigated regarding their mechanical behavior at low temperatures and compared to a non-toughened reference. The application-oriented resins are based on reactive diluent-modified diglycidylether of bisphenol A (DGEBA) which tested 22 °C ?50 in regard fracture toughness (KIC) fatigue crack propagation (da/dN) behavio...

Within the context of seismic wave propagation, fractures can be described as thin layers or linear-slip interfaces. In this paper, numerical simulations of elastic wave propagation in a medium with a single fracture represented by these two models are performed by 2D finite-difference codes: a variable-grid isotropic code for the thin-layer model and a regular-grid anisotropic code for the lin...

Results of “generation” (determination of dynamic stress-intensity factor variation with time, for a specified crack-propagation history) studies, as well as “prediction” (determination of crack-propagation history for specified dynamic fracture toughness vs crack-velocity relationships) studies of dynamic crack propagation in plane-stress/strain situations are presented and discussed in detail...

We study the propagation of brittle fractures coupled to large out-of-plane bending, as when a brittle elastic thin sheet is cut by a moving object. Taking into account the separation of the film's bending and stretching energies and using fracture theory we show that such cracks propagate according to a simple set of geometrical rules in the limit of small thickness. In particular, this provid...

The high-cycle, push-pull fatigue fracture behavior of high-C, Si-Al-rich nanostructured bainitic steel was studied through the measurement of fatigue limits, a morphology examination and phase composition analysis of the fatigue fracture surface, as well as fractography of the fatigue crack propagation. The results demonstrated that the push-pull fatigue limits at 10⁷ cycles were estimated as ...