A crack trapping model is developed for the fracture resistance of high-angle grain boundaries in free-standing brittle thin films, based on which a new size effect is predicted. In addition to the crystallographic misorientations, the grain boundary toughness is also dependent on the film thickness, primarily due to the geometrically necessary crack front branching. 2007 Elsevier Ltd. All righ...

Many polymers and composites have been used to prepare active wound dressings. These materials have typically exhibited potentially toxic burst release of the drugs within the first few hours followed by a much slower, potentially ineffective drug release rate thereafter. Many of these materials also degraded to produce inflammatory and cytotoxic products. To overcome these limitations, composi...

In this study, different amounts of MoS2 particles and an anionic surfactant were added to the conventional chromium electroplating bath in order to electrodeposite crack-free chromium coatings and the structure, morphology, tribology and corrosion behavior of the deposited coatings were investigated using X-ray diffraction spectroscopy, scanning electron microscopy, pin on disk ...

In 2004, a team comprised of researchers and service providers launched the Safer Crack Use, Outreach, Research and Education (SCORE) project in the Downtown Eastside of Vancouver, British Columbia, Canada. The project was aimed at developing a better understanding of the harms associated with crack cocaine smoking and determining the feasibility of introducing specific harm reduction strategie...

that varies with distance, r, from the crack tip as r 1 2 . In this paper, a traction free plane stress wedge with a discrete cohesive zone along the intended crack-path is studied. Of interest is the in uence of the cohesive zone on the crack tip stress eld. Further, the in uence of the cohesive zone on the strain energy release rate is also investigated. Two example problems are studied; a do...

-Properties of elastic solutions to interface crack problems are discussed in both the open formulation, in which the crack faces are assumed to be traction-free and interpenetration is permitted, and the unilateral formulation, where a contact zone is generally established adjacent to the crack tips. It is shown that if the contact zone is sufficiently small compared with the other dimensions ...

Analysis of toughness in 6156 Al-Mg-Si-Cu sheet has been performed using enhanced Kahn tear tests on samples quenched at different rates. Crack initiation energies were hardly affected by changing water quench temperature from 20°C to 60°C; however a significant reduction was evident on air cooling. Crack propagation energy was reduced for both 60°C water quenched and air cooled materials. Obse...

The present paper explores quasi-cleavage processes driven by dislocation pileups against a Dislocation Free Zone (DFZ). The nanoscopic growth of the main crack consists of sequences of nanocrack formation in DFZ and its subsequent linkage with the main crack. Under mode I loading, the equilibrium locations of individual dislocations and the equilibrium number of dislocations are determined by ...