| 释义 |
floatation, flotation|fləʊˈteɪʃən|
[f. float v. + -ation = Fr. flottaison.
The spelling flotation is not etymologically justifiable, but is more common in use, prob. because it disguises the hybrid formation, so that the word appears more conformable to the general analogy of scientific terms.]
1. a. The action, fact, or process of floating, in various senses; the condition of keeping afloat. attrib. Applied to any device that gives buoyancy.
centre of floatation: the centre of gravity in a floating body. plane or line of floatation = Fr. flottaison, ligne de flottaison, the plane or line in which the horizontal surface of a fluid cuts a body floating in it. stable floatation: the position of stable equilibrium in a floating body.
1806Gregory Mechanics I. 377 The plane of floatation is the horizontal surface of the fluid in which the vessel floats. c1850Rudim. Navig. (Weale) 158 Water Lines, or Lines of Flotation. 1853Kane Grinnell Exp. xv. (1856) 115 These constantly shifting centres of flotation. 1853Sir H. Douglas Milit. Bridges (ed. 3) 53 Compared with the stability of the vessel and its power of floatation. 1867W. Pengelly Devon Trans. II. 264 It may be doubted whether [these reasons]..are capable of explaining the floatation of clouds. 1878Markham Gt. Frozen Sea ii. 25 They [icebergs] were of very deep flotation. 1884Sir R. Baggallay in Law Rep. 13 Q. Bench Div. 171 During this period of flotation and transit.
attrib.1883Chamb. Jrnl. 8 Dec. 771/1 Spherical buoys which..show half..their shape above the flotation line. 1928[see float n. 8 e]. 1940Chambers's Techn. Dict. 343/1 Flotation gear, a system of air or gas bags, sometimes with hydrovanes, to enable a land plane, in an emergency, to land and remain afloat, on water. 1958Times 1 Sept. 4/6 A..general-purpose missile..is being shown complete with parachutes and flotation bag; the latter inflates automatically when the missile falls into the sea. 1963Times 17 May 14/1 Divers jumped from the helicopters and attached the flotation collar to the capsule. 1971Times 17 July 5/4 Under your seat there is a floatation device.
b. The separation of particulate material, esp. pulverized ore, by utilizing the varying capacity for floating on a given liquid that results from differences in the surface properties of the particles (rather than from differences in density); freq. attrib. So froth flotation, flotation in which the separation is enhanced by using a liquid to which a frothing agent has been added and bubbling air through it, so forming a froth in which certain of the particles collect.
1908Westm. Gaz. 1 Aug. 15/1, 11,775 tons of dump tailings were treated by the flotation process. 1925Jrnl. Iron & Steel Inst. CXI. 471 The application of flotation-methods to existing coal-washery-plants, and the cost and working expenses of such appliances, are discussed. Ibid. 472 The article describes the application of froth-flotation processes to the recovery of coal from the sludge. 1927Daily Express 15 July 10/1 The original ore is readily amenable to treatment by flotation. 1951Kirk & Othmer Encycl. Chem. Technol. VI. 595 Separations made by flotation include not only the concentration of base-metal ores but also widely divergent applications such as the separation of ink from repulped paper stock, of peas from pea pods, [etc.]. 1968Coulson & Richardson Chem. Engin. (ed. 2) II. xvii. 704 Froth flotation is widely used in the metallurgical industries where, generally, the ore is difficult to wet and the residual earth is readily wetted. 1970Materials & Technol. III. ii. 117 Many flotation plants treat over 20,000 tonnes of ore per day.
2. The action of floating a company or enterprise.
1889Financial Times 23 Jan. 1 The London Mexican Prospecting and Finance Company, Limited. Since its flotation it has [etc.]. 1893Westm. Gaz. 1 May 6/1 The flotation of this mine..is now contemplated.
▸ spec. The action or an act of floating in a buoyant salt solution heated to body temperature inside a special light-proof, sound-proof tank, in order to achieve sensory deprivation and hence relaxation. Usu. attrib., esp. in flotation tank (cf. isolation tank n. at isolation n. Additions).
1977Libr. Jrnl. 15 June 1390/1 For the past few years, he has lived in California where he maintains five flotation tanks. 1985New Yorker 3 June 35/1 Flotation centers—commercial operations with a number of the sensory-deprivation tanks available for use by the hour—were opening across the country. 1992Weekend Independent (Brisbane) 11 Dec. 17/2 Some of the more popular techniques include massage, flotation, meditation, yoga and tai chi. 2001News (Mexico) (Electronic ed.) 7 Feb. Sulkin says that one hour inside the flotation tank is equivalent to eight hours of sleep. ‘You essentially lose your sense of touch. You become disconnected from the external stimuli of the outside world.’ |