The fatigue process is viewed as the result of the competing processes of crack growth and crack healing. The crack growth or damage proctss is ont of micrOCnlck development and growth and ultimately coalescence of microcraclc.s and propagation in the form of macrocracks. During the entire process, and especially during the period of microcrack growth, microdamage healing strongly influences th...

The volumetric expansion of freezing pore water is widely assumed to be a major cause of rock fracture in cold humid regions. Data from experiments simulating natural freezing regimes indicate that bedrock fracture results instead from ice segregation. Fracture depth and timing are also numerically simulated by coupling heat and mass transfer with a fracture model. The depth and geometry of fra...

Calculations indicate that the introduction of hydrogen into the body–centred cubic and face-centred cubic allotropes of iron in both cases reduces the {100} surface energy. The reduction is rather small in magnitude so this mechanism cannot present the major cause of the well–known hydrogen embrittlement phenomenon. Consistent with the theory of grain boundary embrittlement in iron, carbon is ...

Introduction: The hypothesis explored here is that asteroid 433 Eros, a relatively large (~33 km x 13 km x 13 km) rocky near-Earth asteroid, is structurally similar to the upper meters of the Moon – that it is globally a dry rocky dust-rich regolith, beaten apart by eons of cosmic impacts, but under 1/300 th the gravity. According to this view, the fractures expressed on the surface of Eros – a...

The topographical features of fractured tensile, flexural, K1C, and impact specimens of monolithic epoxy have been studied and correlated with mechanical properties and surface features of samples before fracture. The topographical features studied include waviness (Wa), roughness average (Ra), root mean square value (Rq), and maximum roughness height (Rmax or Rz). As surface notches generate t...

A study has been made of freeze-fractured preparations of erythrocyte ghosts modified by phospholipase C (Clostridium welchii). Such membranes show a decrease in surface area of up to about 47% and lipid droplets appear on their external surface but there is no loss of protein. Freeze-fracture of maximally hydrolysed membranes exposes only very small areas of A faces and these appear particle-f...

INTRODUCTION Preventing post-traumatic osteoarthritis is a challenging problem following acetabular fracture. Progressive osteoarthritis is considered to be caused by an irregular articular surface of the acetabular roof or cartilage injury, but little is known about the pathogenesis of collapse of the femoral head after acetabular fracture. We report a case of post-traumatic osteoarthritis aft...

Long-term durability is a major obstacle limiting the widespread use of lithium-ion batteries in heavy-duty applications and others demanding extended lifetime. As one of the root causes of the degradation of battery performance, the electrode failure mechanisms are still unknown. In this paper, we reveal the fundamental fracture mechanisms of single-crystal silicon electrodes over extended lit...

The effect of ferrite grain size on the fatigue and tensile properties of dual phase steels with a 0.25 volume fraction of martensite (Vm) under different heat treatments was investigated. The heat treatments were homogenized at 1200 oC along with several subsequent normalizations at 910 oC, resulting in different microstructures and mechanical properties. After heat treatment, the obtained ste...

Trypanosomatids cell surfaces play an important role in the interaction process with the cells of their vertebrate hosts as well as with the epithelial intestinal cells of the invertebrate hosts. The surface of these eukaryotic organisms is considered to be made up of the glycocalix, the lipid bilayer and a layer of microtubules linked to the lipid bilayer. The surface of the infective forms ex...