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aquaponics

(Encyclopedia)aquaponics, the growing of plants and the raising of fish by combining aquaculture with the techniques of hydroponics, usually on a small scale. Water containing fish waste matter is used as the nutri...

Archimedes' screw

(Encyclopedia)Archimedes' screw, a simple mechanical device believed to have been invented by Archimedes in the 3d cent. b.c. It consists of a cylinder inside of which a continuous screw, extending the length of th...

cupric sulfate

(Encyclopedia)cupric sulfate ko͞oˈprĭk sŭlˈfāt, kyo͞oˈ– [key] or copper (II) sulfate, chemical compound, CuSO4, taking the form of white rhombohedral crystals or amorphous powder. It decomposes at 650℃ ...

Amu Darya

(Encyclopedia)Amu Darya or Amudarya both: ämo͞oˈ däryäˈ, äˈmo͞o därˈyə [key], river, c.1,600 mi (2,580 km) long, formed by the junction of the Vakhsh and Pandj rivers, which rise in the Pamir Mts. of ce...

hydroponics

(Encyclopedia)hydroponics, growing of plants without soil in water to which nutrients have been added. Hydroponics has been used for over a century as a research technique, but not until 1929 were experiments condu...

boiler

(Encyclopedia)boiler, device for generating steam. It consists of two principal parts: the furnace, which provides heat, usually by burning a fuel, and the boiler proper, a device in which the heat changes water in...

liposome

(Encyclopedia)liposome līˈpəsōmˌ, lĭpˈə– [key], microscopic, fluid-filled pouch whose walls are made of layers of phospholipids identical to the phospholipids that make up cell membranes. Liposomes are us...

snorkel

(Encyclopedia)snorkel, tube through which a submarine or diver can draw air while underwater. When in use, the top of the snorkel tube extends above the water surface into the air. The first snorkels were probably ...

well

(Encyclopedia)well, aperture in the earth's surface through which substances in a natural underground reservoir, such as water, gas, oil, salt, and sulfur, can flow or be pumped to the surface. In the United States...

molecular weight

(Encyclopedia)molecular weight, weight of a molecule of a substance expressed in atomic mass units (amu). The molecular weight may be calculated from the molecular formula of the substance; it is the sum of the ato...