-The Cocos plate subducts beneath North America at the Mexico trench. The northernmost segment of this trench, between the Orozco and Rivera fracture zones, has ruptured in a sequence of five large earthquakes from 1973 to 1985: the Jan. 30, 1973 Colima event (M, 7.5) at the northern end of the segment near Rivera fracture zone; the Mar. 14, 1979 Petatlan event (M s 7.6) at the southern end of ...

We measure the thickness of the heavy water layer trapped under the stress corrosion fracture surface of silica using neutron reflectivity experiments. We show that the penetration depth is 65-85   Å, suggesting the presence of a damaged zone of ∼100   Å extending ahead of the crack tip during its propagation. This estimate of the size of the damaged zone is compatible with other recent results.

To summarize the clinical features of eyeball rupture with or without orbital fracture and explore the differences between them.In all, 197 patients were observed, and the following data were recorded: sex, age, time of injury, place of injury, cause of trauma, zone of eye injury, intraocular content prolapse, surgical methods and the therapeutic process, visual acuity after injury, and the fin...

[1] A single plane fracture with an axially symmetric stress distribution behaves as a seismic lens that focuses seismic energy to a beam ‘‘waist’’ at a focal plane. Both phase and amplitude effects on a seismic wave propagating across the fracture contribute to the lensing behavior. Radial gradients in the fracture specific stiffness cause wave refraction through a radially varying group time ...

It is well known that when coarse-grained metals undergo severe plastic deformation to be transformed into nano-grained metals, their ductility is reduced. However, there are no ductile fracture criteria developed based on grain refinement. In this paper, we propose a new relationship between ductile fracture and grain refinement during deformation, considering factors besides void nucleation a...

Waves reflected from and transmitted across fault zones can be used to extract information on those zones. Fault zones, characterized as either a low-velocity zone or fracture systems, modify the phase of the waveform and make the seismic response frequency dependent. In this paper we develop an extrapolation scheme for simulating fractures described as linear slip boundaries. Two 9 × 9 linear ...

Damage and fracture mechanisms of two 2198 Al-Li thin sheet alloys having different thicknesses (2 and 6 mm) are investigated. Two heat treatments are studied: T3 and T8. Mechanical tests are carried out on flat specimens including smooth tensile samples and U-notched specimens (with various notch radii). Test data are used to identify the parameters of constitutive equations describing plastic...

The aim of this study was to clarify the effects of micro surface defects introduced by the focused ion beam (FIB) technique on the fracture strength of ceramics. Three-point bending tests on alumina-silicon carbide (Al₂O₃/SiC) ceramic composites containing crack-like surface defects introduced by FIB were carried out. A surface defect with area in the range 19 to 35 µm was introduced at the ce...

A 76-year-old man presented with a Denis Zone III sacral fracture after a traffic accident. He also developed urinary retention and perineal numbness. The patient was diagnosed with neurogenic bladder dysfunction caused by the sacral fracture. A computed tomogram (CT) revealed that third sacral lamina was fractured and displaced into the spinal canal, but vertebral body did not displace. The fr...