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Technology (Greek technologia (τεχνολογία) < techne (τέχνη) "craft" + -ologia (-ολογία) "science or discipline") is the application of developments in science and engineering to benefit humanity. It may be defined as: "Solutions for real human problems by the development and application of tools, machines, materials, goods, or information in the form of skills, knowledge, processes, blueprints, plans, diagrams, models, formulae, tables, engineering designs, specifications, manuals, or instructions."

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Cavitation is the formation of vapour bubbles of a flowing liquid in a region where the pressure of the liquid falls below its vapor pressure. Cavitation is usually divided into two classes of behavior: inertial (or transient) cavitation, and noninertial cavitation. Inertial cavitation is the process where a void or bubble in a liquid rapidly collapses, producing a shock wave. Such cavitation often occurs in pumps, propellers, impellers, and in the vascular tissues of plants. Noninertial cavitation is the process in which a bubble in a fluid is forced to oscillate in size or shape due to some form of energy input, such as an acoustic field. Such cavitation is often employed in ultrasonic cleaning baths and can also be observed in pumps, propellers, etc.

Inertial cavitation was first studied by Lord Rayleigh in the late 19th century, when he considered the collapse of a spherical void within a liquid. When a volume of liquid is subjected to a sufficiently low pressure, it may rupture and form a cavity. This phenomenon is termed cavitation inception and may occur behind the blade of a rapidly rotating propeller or on any surface vibrating underwater with sufficient amplitude and acceleration. A fast-flowing river can cause cavitation on rock surfaces, particularly when there is a drop-off, such as on a waterfall.

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Credit: User:Leonard G.

Alhambra creek railway trestle, Martinez, California.

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Did you know...

... that both the Mozilla Firefox and Microsoft Internet Explorer web browser design ideas descended from the Mosaic web browser?

... that a coherer, hot wire barretter, electrolytic detector, cat's whisker and vacuum tube were all types of radio detectors?

... that in 2008 Hewlett-Packard created a prototype of the theoretical fourth and last passive circuit element, the memristor, that may one day revolutionize electronics, although the theory was devised in 1971?

... that a mercury arc rectifier converts alternating current to direct current by means of an electric arc through mercury vapor?

... that only one of the 266 1076 Class steam locomotives built for the Great Western Railway was named, and the rest had only numbers?

... that the six Charles Tayleur locomotives ordered by Isambard Kingdom Brunel for the Great Western Railway were unsuccessful?

Tropical Storm Wilma regional imagery, 2005

... that the intensity of a tropical cyclone (pictured) is usually determined by the Dvorak technique using only visible and infrared satellite images?