Fracture surfaces are produced by breaking a solid. The appearance of the surface, particularly the topography, depends on the type of material - metal, polymer, ceramic, biomaterial, composite, rock - and on the conditions under which it was broken - stress (tensile, shear, creep, fatigue, impact), temperature, environment (air, water, oil, acid), etc.  Meer

The sleekest bird in the skies carries a lethal payload - a new Air Force adventure from the author of Goshawk Squadron, set during the darkest days of the Cold War.  Meer