BACKGROUND We have developed a new surgical instrument, called the pulsed electron avalanche knife (PEAK; Carl Zeiss Meditec, Jena, Germany), for precise, "cold," and tractionless dissection of tissue in liquid media. OBJECTIVE To evaluate the 3-dimensional damage zone induced by the PEAK compared with 2 other standard intraocular surgical instruments, diathermy and retinal scissors. METHOD...

introduction vulnerability is a term used to show the amount and extent of damage and the losses caused by natural disasters in different communities (social, formal-physical, etc.). vulnerabilities is identified as the sensitivity of the environment against the hazards. from among natural disasters, earthquakes can have a vast scope of losses for desert regions. therefore, in order to reduce a...

BACKGROUND Detailed fluorescein angiographic findings in the disc circumference may be useful for evaluating the possible relation of the circumference to glaucomatous nerve damage. METHODS Fluorescein angiograms of 25 eyes of 25 subjects with primary open angle glaucoma were observed after they had undertaken Octopus perimetry. Based on the retinotopic projection, disc sectors and correspond...

The brittle portion of the Earth’s lithosphere contains a distribution of joints, faults and cataclastic zones that exist on a wide range of scale-lengths and usually have complex geometries including bends, jogs, and intersections. The material around these complexities is subjected to large stress concentrations, which lead during continuing deformation to the generation of new fracture and g...

While the use of protective clothing has been shown to reduce the risk of injury for motorcycle riders, not all protective clothing performs the same in crashes. A European standard for motorcycle protective clothing (EN13595) was released in 2002. Riders that use clothing approved to this Standard should expect good protection. This standard specifies four zones in motorcycle clothing with dif...

It has been widely reported that coal permeability can change from reduction to enhancement due to gas adsorption even under the constant effective stress condition, which is apparently inconsistent with the classic theoretical solutions. This study addresses this inconsistency through explicit simulations of the dynamic interactions between coal matrix swelling/shrinking induced damage and fra...

Fiber fractures in metal-matrix composites often initiate damage zones that grow until the composite fails. To better understand the evolution of such damage from a micromechanics point of view, a model Ti-matrix/SiC-fiber composite was studied for the first time. Using high energy X-rays and a small sampling volume, the damage zone around a broken fiber was investigated. The growth of this zon...

Abstract Fault damage zones strongly influence fluid flow and seismogenic behavior of faults are thought to scale linearly with fault displacement until reaching a threshold thickness. Using analog modeling different frictional layer thicknesses, we investigate zone dynamic evolution during normal growth. We show that experimental growth is not linear but progressively tends toward thickness, b...