Catastrophic initiation of an energetic material consists of a complex, interactive, sequential train of mechanistic mechanical, physical, and chemical processes which occur over a finite time period and proceed from macroscopic into sub-microscopic composition levels (bulk > crystalline > molecular > atomic). Initiation results when these processes proceed at a rate which generates sufficient ...

We investigate the thermodynamics and kinetics of DNA hairpins that fold/unfold under the action of applied mechanical force. We introduce the concept of the molecular free energy landscape and derive simplified expressions for the force dependent Kramers–Bell rates. To test the theory we have designed a specific DNA hairpin sequence that shows two-state cooperative folding under mechanical ten...

We have carried out numerical simulations of seismic ground motion radiating from a mega-earthquake whose rupture process is governed by a multi-scale heterogeneous distribution of fracture energy. The observed complexity of the Mw 9.

premature rupture of membranes (prom) is one of the most common complications of pregnancy that has a major impact on neonatal outcomes. with respect to racial, nutritional and cultural differences between developed and developing countries, this study was conducted to detect the prevalence of neonatal complications following prom and the role of the duration of rupture of membranes in producin...

– Slow crack growth in a model of homogenous brittle elastic material is described as a thermal activation process where stress fluctuations allow to overcome a breaking threshold through a series of irreversible steps. We study the case of a single crack in a flat sheet for which analytical predictions can be made, and compare them with results from the equivalent problem of a 2D spring networ...

The arterial wall is a composite where the preferred orientation of collagen fibers induces anisotropy. Though the hyperelastic theories of fiber-reinforced composites reached a high level of sophistication and showed a reasonable correspondence with the available experimental data they are short of the failure description. Following the tradition of strength of materials the failure criteria a...

Accurate prediction of the intensity and variability of strong ground motions for future large earthquakes depends on our ability to simulate realistic earthquake source models. While there has been considerable progress in characterizing the complexity of earthquake ruptures, recent devastating earthquakes have exhibited rather unexpected behavior. Moderate-size events occurred with surprising...

In order to assess the physical mechanisms at stake when giant gas bubbles burst at the top of a magma conduit, laboratory experiments have been performed. An overpressurized gas cavity is initially closed by a thin liquid film, which suddenly bursts. The acoustic signal produced by the bursting is investigated. The key result is that the amplitude and energy of the acoustic signal strongly dep...

This paper presents a hydrodissection technique performed with high-speed pulse injection of only 0.1 cc liquid and assess its efficacy, safety, and the level of reduction in posterior capsule rupture complications in phacoemulsification cataract surgery. The kinetic energy of moving objects is directly proportional to the mass and to the square of its velocity. The high energy obtained by high...