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As an approximation, the roughness length is approximately one-tenth of the height of the surface roughness elements. For example, short grass of height 0.01 meters has a roughness length of approximately 0.001 meters. Surfaces are rougher if they have more protrusions. Forests have much larger roughness lengths than tundra, for example.
The power law is often used in wind power assessments [4] [5] where wind speeds at the height of a turbine ( 50 metres) must be estimated from near surface wind observations (~10 metres), or where wind speed data at various heights must be adjusted to a standard height [6] prior to use.
PGA records the acceleration (rate of change of speed) of these movements, while peak ground velocity is the greatest speed (rate of movement) reached by the ground, and peak displacement is the distance moved. [7] [8] These values vary in different earthquakes, and in differing sites within one earthquake event, depending on a number of ...
Micro ball grid array : Ball spacing less than 1 mm; Thin fine-pitch ball grid array : A square or rectangular array of solder balls on one surface, ball spacing typically 0.5 mm; Land grid array (LGA): An array of bare lands only. Similar to in appearance to QFN, but mating is by spring pins within a socket rather than solder.
Aluminium–copper alloys (AlCu) are aluminium alloys that consist largely of aluminium (Al) and traces of copper (Cu) as the main alloying elements.Important grades also contain additives of magnesium, iron, nickel and silicon (AlCu(Mg, Fe, Ni, Si)), often manganese is also included to increase strength (see aluminium-manganese alloys).
Demand for a good is said to be inelastic when the elasticity is less than one in absolute value: that is, changes in price have a relatively small effect on the quantity demanded. Demand for a good is said to be elastic when the elasticity is greater than one. A good with an elasticity of −2 has elastic demand because quantity demanded falls ...
It was once expected that any icy body larger than approximately 200 km in radius was likely to be in hydrostatic equilibrium (HE). [7] However, Ceres (r = 470 km) is the smallest body for which detailed measurements are consistent with hydrostatic equilibrium, [ 8 ] whereas Iapetus (r = 735 km) is the largest icy body that has been found to ...
The leaves are mostly green in color, but the accumulation of anthocyanins, especially along the leaf veins, can make them purple. Depending on the variety, the total length of a stem can be between 0.5 and 4 metres (1 + 1 ⁄ 2 and 13 feet). Some cultivars also form shoots up to 16 m (52 ft) in length. However, these do not form underground ...