Search Results

Technologies to optimize the performance of optical systems wherein controllable optical elements maintain a sharply focused image in the presence of wavefront aberrations. The practical development of adaptive optics started in the late 1960s. Main…

An ongoing current event in which a large number of living species are threatened with extinction or are going extinct because of environmentally destructive human activities. The Earth is presently in the midst of a mass extinction event. In the…

Earth's oldest desert and the most arid place outside of Antarctica's Dry Valleys. Located along the edge of the Pacific Ocean and to the west of the Andes in Chile's Antofagasta Province, the Atacama Desert (Fig. 1) has long been recognized as…

An analytical technique for determining the composition of a sample in terms of the chemical elements present and their quantities or concentrations. Unlike other methods of elemental analysis, however, the sample is decomposed into its constituent…

A quantum-mechanical theory of the motion of electrons in solids. The band theory of solids' name comes from the fact that it predicts certain restricted ranges, or bands, for the energies of electrons in solids. In a solid, the energy level of an…

Humans have used dried bovine dung (manure) as a fuel source since prehistoric times. In India, for example, many people burn cow or buffalo dung for cooking fuel. This bioresource provides a low-cost fuel as well as an efficient means of waste…

That portion of a fluid flow near a solid surface where shear stresses are significant and the inviscid-flow assumption, in which viscous-shear and normal stresses are negligible, may not be used. In physics broadly and fluid mechanics specifically,…