GIDROIDNYE, a class of water Invertebrata of type knidary. 5-6 orders, including hydras; ok. 4000 kinds. The majority - colonial marine animal of which alternation sexual (medusas) and asexual (polyps) of generations is typical.

HYDROISOBATHS, isolines of depths of a mirror of underground waters from a surface.

HYDROISOHYPSES, isolines of marks of a mirror of underground waters concerning a conditional null surface.

WATERPROOFER, protection of designs, buildings and structures from influence on them waters and other liquids, the warning of escape of process iquids, and also a means used for these purposes.

HYDROISOPLETHS, isolines of a soil moisture on different depths in miscellaneous time; points of equal water levels in miscellaneous wells in miscellaneous time (see. Isopleths).

HYDROISOTHERMS, isolines of temperature of water in the given strata of rocks.

HYDROCARBONATES (bicarbonates), acid salts of metacarbonic acid Í2ÑÎ3, napr., baking soda NàÍÑÎ3.

HIDROCORTIZONUM (hydrocortisone), hormone animal and the person, produced by a bark of suprarenal glands (corticosteroid). Participates in a regulation carbohydrate, proteinaceous and an adipose metabolism in an organism; boosts disintegration of proteins and synthesis of carbohydrates. Apply in medicine, primarily as an anti-inflammatory and antiallergic means, and also at his failure in an organism.

RECOVERY SUIT (immersion suit), part of diving equipment; protects the diver from overcooling and traumas. Distinguish recovery suits water-proof (from rubber cloth) and water-permeable (from foam rubber).

HYDROCRACKING, thorough revision of higher-boiling oil fractions, fuel oil or tar for obtaining petrol, diesel and reactive combustibles, greasing oils, etc. Carry out action of hydrogen at 330-450 °S and pressure 5-30 MPa at the presence of catalysts.

The HYDROX, way of a non-flame blasting, is based on instantaneous reaction inside the cartridge (also called by a hydrox) the mix of chemicals attending with a calorification and education of a plenty of water steams in a mix with carbon dioxide and nitrogen.

OXYHYDROXIDES, chemical combinations of oxides with water. Oxyhydroxides of many metals - the groundings, and metalloids - acids. The oxyhydroxides showing as main, and acid properties, call amphoteric. Routinely the term "oxyhydroxide" concerns only to the groundings. See also Alkalis.

OXYHYDROXIDES NATURAL, subclass (or a class) minerals, natural water oxides of metals. On crystalline structure distinguish layered, chain, less often framed oxyhydroxides natural. Will derivate large deposits (napr., bauxites, iron, manganous, uranic, vanadic ores).

HYDROXYLAMINE, NH2OH, colourless crystals; tïë 32 °S. Beyond all bounds we shall dissolve in water. It is toxicant. Interacting with acids, will derivate salt, napr. (NH3OH) 2SO4. Apply in manufacture of caprolactam, in an analytical chemistry.

HYDROXONIUM, Í3Î +, a hydrated ion of hydrogen; exists in water solutions of acids.

HYDROLASE, a class of the ferments catalyzing reactions of a hydrolysis, i.e. scission of organic compounds including waters. Many digestive enzymes concern to hydrolases; a number of hydromanholes use in a food-processing industry.

HYDROLYSIS (from gidro... And... liz), an exchange reaction (double replacement) between substance and water, napr., AlCl3 + 3H2O? Al (OH) 3 + 3HCl. The basis of many technological and natural processes.

The HYDROLOGICAL STATION, 1) executes study of a hydrological regime of the rivers, lakes, seas, water reservoirs, bogs, icehouses. 2) Point with fixed coordinates on the pest (lake) where a series of hydrological observations is carried out.

HYDROLOGICAL MAPS, map distribution of waters above ground, define a mode of water objects and allow to estimate water resources.

HYDROLOGICAL PROGNOSES, the section of land hydrology including a scientific forecast of development of those or other processes, descending on the rivers, lakes or water reservoirs, definition of their times and parameters. Distinguish hydrological prognoses: on kinds - water (volume seasonal and pavodochnogo a drainage, maximum and minimum discharges of water and levels) and ice (times of dissection and freezing of the rivers, lakes, water reservoirs, an ice depth, etc.); on a forecast-time interval - near-term (up to 15 sut), long-term (about several months) and superlong-term.