CATARACT, fall of water in the river from the terrace crossing a river race course. Water can drop on several terraces, derivating a series of cataracts - the cascade; less abruptly dropping cataracts call as waterfalls.

WATER RECLAMATION, reduction of quality of the water used in the technological purposes on different industrial enterprises, and also systems vodo-and heating, etc., in correspondence with requests of consumers.

WATER HEATER (water heater), the heat-exchange apparatus for calefaction of water the ferry, hot water (or gases) with the help of heated bodies, etc. Distinguish water heaters with surface heating (warmly it is transmitted to water at its contact with a surface of heated elements) and with conduction heating (warmly is transmitted to water hot the ferry or gas).

The WATER-RAISING MACHINE (water elevator), the device for non-ramming sloshing (primarily waters). Protozoa water-raising machines - a crane and a gate for a water lifting from the well. Continuous feeding of water implements water-raising machines: the Archimedean screw, a water-raising sprocket, a chain pump.

The WATER-RAISING SPROCKET, the water-raising machine - a sprocket a dia of 2-6 m with loosely hanging scoops which sprockets at rotation scoop water and are drained (being toppled over) above a tray. Sometimes instead of scoops - hardly reinforced vanes.

WATER INTAKE, channel, water reservoir or the hollow accepting and deflecting, collected by a bilge arrangement from accumbent terrain. The term "water intake" use also for notation of hydrotechnical abstraction intakes.

The WATER-PIPE, see. Water supply.

WATER SYSTEM, set of water lines (pipe lines) for water delivery to places of consumption; one of basic elements of water handling.

VODOPJANOV Michael Vasilyevich (1899-1980), the Russian pilot, the Hero of Soviet Union (1934), the general - major of aircraft (1943). In 1934 participant of salvage of crew of motorship " ×åëþñêèí ", in 1937 - air expedition on an arctic pole. In Great Domestic war the commander of an air division.

WATERSHED, border on a surface of the Earth, dividing a drainage of a rainfall on two counterly directed downslopes. A ground water divide - the conditional line dividing torrents of underground waters, driving in miscellaneous directions.

The WATER-PARTITE SPACE, on plains - an interfluve which is not having a drainage in any river system or with a drainage, implementing slabovrezannymi verhovjami the rivers; in mountains - a central part of a crops, accumbent to a watershed.

HYDROGEN (an armour. Hydrogenium), N, a chemical element of VII group of a periodic system, atomic number 1, atomic weight 1,00794. In a nature there are two stable isotopes (protium and deuterium) and one radioactive (hyzone). The molecule is biatomic (Í2). Gas without colour and an odor; firmness 0,0899 g/l, têèï = 252,76 °S. It is bridged to many elements, with oxygen will derivate water. The most widespread element of cosmos; compounds (by the way plasma) more than 70 % of mass of the Sun and asters, a main body of gases of interstellar medium and fogs. On the Earth is part some water, living organisms, mineral coal, petroleum. Apply in manufacture of ammonia, muriatic acid, to oil hardening, etc., at a weldment and metal cutting. Is part some synthesis gas. It is long-range as combustible (see. Hydrogenous energetics).

HYDROGEN BOMB, the obsolete title of a nuclear bomb of a major destruction force, which action it is based on use of the power secreted at a synthetic reaction of light nucleus (see. Thermonuclear reactions). For the first time the hydrogen bomb has been tested in the USSR (1953).

The HYDROGENOUS ENERGETICS, actuates obtaining Í2 from water and other natural raw material with an expenditure of solar, nuclear or other power, his storage and use as fuel, and also in chemical transmission modes of power. Main advantage: high combustion heat (143,06 MDZH/KG) as contrasted to hydrocarbon fuel (29,3 MDZH/KG); unlimited stocks of raw materials if in the capacity of raw material to consider water, and an ecological security, t. To. A product of his combustion - water. The hydrogenous energetics yet has not received mass application. The main problems: development of economic productive instrumentation for obtaining Í2, napr., electrolytic cells, plasma generators; his storage methods in the gaseous and liquefied conditions or by the way the synthesized connections, napr., hydrides of intermetallic compound; a transporting with small loss.

HYDROGEN-HELIUM CYCLE (proton - proton chain), chain of thermonuclear reactions of metamorphosis of hydrogen in helium without sharing catalysts. A hydrogen-helium cycle - the main energy source of the majority of asters, including. The Suns.

The HYDROGEN ELECTRODE in the electrochemistry, routinely platinized plate which is submersed in a solution of an acid with fixed ion density N + and washed against by gaseous hydrogen. At pressure of hydrogen 0,1 ÌÏa and thermodynamic activity of his ions, equal unit, the potential of the hydrogen electrode is conditionally adopted equal to zero. Such hydrogen electrode calls standard, he ministers a reference electrode from which read out potentials of other electrodes.

HYDROGEN-LIKE ATOMS, atom N and the ions consisting, as well as N, from a nucleus and one electron (napr., single-passly ionized Not, twofoldly ionized Li). To hydrogen-like atoms attribute also atoms and ions with one vysokovozbuzhdennym (ridbergovskim) an electron. Spectrums of hydrogen-like atoms are similar to spectrum N.