sedimentationn.
/ˌsɛdɪmənˈteɪʃən/ Deposition of sediment; spec. in Geology (see sediment n. 2); also see quot. 1898.
ΘΚΠ
the world > the earth > structure of the earth > formation of features > sedimentation > [noun]
sedimentation1874
resedimentation1894
1874 H. A. Nicholson in Trans. Victoria Inst. IX. 215 There is no proof of any considerable pauses in the process of sedimentation during the same period.
1881 Geikie in Nature 17 Feb. 358/1 That still comparatively narrow belt of sea to which sedimentation has always been mainly confined.
1896 Appletons' Pop. Sci. Monthly Dec. 243 I am inclined..to ascribe the greatest potency to the effects of erosion, transportation, and sedimentation on the earth's surface.
1898 New Sydenham Soc. Lexicon Sedimentation, production of quick deposition of a sediment, whether in sewage, or urine, &c., by means of some centrifugal apparatus.
1902 Westm. Gaz. 20 Dec. 3/1 River water is usually purified by sedimentation and filtration.
Compounds
sedimentation coefficient n.
ΚΠ
1962 H. Bloemendal et al. in A. Pirie Lens Metabolism 300 α-Crystallin, prepared by vertical starch block electrophoresis, has a sedimentation coefficient of 19 S (molecular weight 810,000).
1978 Nature 12 Jan. 170/2 Nervous tissue and muscle in rat and chicken contain several molecular forms of acetylcholinesterase.., distinguishable by their sedimentation coefficient in sucrose gradient.
sedimentation constant n. a measure of the size of a microscopic particle, equal to the terminal outward velocity of the particle when centrifuged in a fluid medium divided by the centrifugal force acting on it; (expressed in units of time: cf. Svedberg n.).
ΚΠ
1929 Svedberg & Katsurai in Jrnl. Amer. Chem. Soc. LI. 3577 The term ‘Sedimentation Constant’ has been adopted as a simplified means of expressing the old term ‘Specific Sedimentation Velocity’.
1966 B. Pollara et al. in R. T. Smith et al. Phylogeny of Immunity ix. 94/2 The antibody produced by this animal is different from that of the other lower vertebrates, having a sedimentation constant of approximately 9S.
sedimentation rate n. the rate of descent of particles suspended in a fluid; spec. in Medicine, of the red cells in drawn blood.
ΚΠ
1946 Nature 30 Nov. 794/2 In accordance with Stokes's law, sedimentation-rates of such red-cell aggregates will be greater than those of single non-polarized blood cells.
1978 Nature 12 Oct. 532/1 To predict long-range trends in marsh stability, accurate measurements are needed of both subsidence and sedimentation rates.
sedimentation tank n. a tank in which sewage is allowed to stand so that the solid matter in suspension may have time to settle.
ΘΚΠ
the world > physical sensation > cleanness and dirtiness > sanitation > provision of sewers > sewage treatment > [noun] > apparatus for sewage treatment
septic tank1896
percolating filter1901
contact bed1902
trickling filter1903
bacteria bed1913
sedimentation tank1920
septic1929
comminutor1939
1920 Glasgow Herald 3 Nov. 13 The sewage passes into a sedimentation tank designed so as to bring down in the form of sludge as much of the suspended solids as possible.
1966 McGraw-Hill Encycl. Sci. & Technol. (rev. ed.) XII. 221/2 In some [sewage] treatment plants screenings are passed through a grinder and returned to the flow so that they will settle out in the sedimentation tank.
This entry has not yet been fully updated (first published 1911; most recently modified version published online June 2018).
<
n.1874