permeabilityn.
/ˌpəːmɪəˈbɪlᵻti/, U.S. /ˌpərmiəˈbɪlᵻdi/ 1.
a. The quality or condition of being permeable; ability to be permeated, perviousness; (Science) the degree to which a solid allows the passage through it of liquid or gas (measured by the coefficient of permeability).
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the world > movement > motion in a certain direction > movement over, across, through, or past > [noun] > through any medium or space > permeation > ability to be permeated
perviousness1660
permeableness1684
permeability1760
transpirability1864
society > occupation and work > materials > types of material generally > working qualities of materials > [noun]
fusibility1624
malleability1644
fusibleness1684
pliability1725
plasticity1727
impermeability1755
unvitrescibility1786
vitrescibility1786
workableness1791
refractoriness1805
pumpability1881
permeability1882
mouldability1890
alkalinity1892
machinability1921
paintability1926
spinnability1939
processability1941
wear-resistance1946
extrudability1981
the world > matter > chemistry > physical chemistry > solid phase > [noun] > permeability
permeability1902
coefficient of permeability1917
permeability coefficient1960
1760 Philos. Trans. 1759 (Royal Soc.) 51 328 Confirmations of the permeability of glass.
1805 W. Saunders Treat. Mineral Waters (ed. 2) 487 The permeability of the skin to heat.
1882 A. Geikie Text-bk. Geol. iii. ii. ii. §2. 351 The permeability of subterranean rocks.
1902 Sci. Abstr.: Physics & Electr. Engin. 5 856 (heading) Permeability of animal membranes.
1920 Rep. & Mem. Advisory Comm. Aeronaut. No. 360. 4 The average permeability of rubbered airship fabrics..is not usually much less than 10 litres per sq. metre per day.
1962 R. C. S. Walters Dam Geol. xiv. 67 The permeability [of the Oxford clay] ranged from 12 × 10−6 to 4·1 × 10−6 cm per sec.
1984 J. F. Lamb et al. Essent. Physiol. (ed. 2) iv. 87 The lymph vessels must have a high permeability to protein.
1993 E. K. Sedgwick in M. Edmundson Wild Orchids & Trotsky 263 There is a valued place for affective expressiveness, and an intellectually productive permeability in the boundaries between public and private.
b. Physics and Soil Science. coefficient of permeability n. the volume of fluid flowing through unit cross-section in unit time under a unit pressure or concentration gradient. Also permeability coefficient.
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the world > matter > chemistry > physical chemistry > solid phase > [noun] > permeability
permeability1902
coefficient of permeability1917
permeability coefficient1960
1917 Rep. & Mem. Advisory Comm. Aeronaut. No. 317. 4 This permeameter is readily adapted to the determination of temperature coefficients of permeability.
1960 Jrnl. Gen. Physiol. 43 523 (heading) Experimental study of the independence of diffusion and hydrodynamic permeability coefficients in collodion membranes.
1966 McGraw-Hill Encycl. Sci. & Technol. (rev. ed.) XII. 453/2 The permeability coefficient varies from 100 cm/sec for clean gravel to 10−9 cm/sec for heavy clay.
1997 Limnol. & Oceanogr. 42 1549/1 Acetate has a relatively high permeability coefficient across membranes.
2. Physics. (More fully magnetic permeability) one of the physical parameters of a medium, equal to the ratio of the magnetic induction B to the magnetic field strength H at any point in it (symbol μ; SI unit, henry metre−1); (also, more fully relative permeability) the ratio of the magnetic permeability of a medium to that of free space; permeability of free space n. a constant μ0 which in the cgs electromagnetic system of units is one and in the SI System is defined as a base quantity with the value 4π (= 12.57) × 10−7 henry metre−1.Of the different permeabilities mentioned in quot. 1872, the magnetic kind is the only one that gained currency.
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the world > matter > physics > electromagnetic radiation > electricity > electrically induced magnetism > electromagnetic induction > [noun] > conducting power
permeability1872
permeance1885
perviability1895
the world > matter > physics > electromagnetic radiation > magnetism > [noun] > magnetic field > lines of magnetic force > conducting power of
magnetic permeability1872
perviability1895
the world > matter > physics > electromagnetic radiation > electricity > electrically induced magnetism > electromagnetic induction > [noun] > conducting power > constant
permeability of free space1988
1872 W. Thomson in Papers Electrostatics & Magn. 484 We have thermal permeability, a synonym for thermal conductivity; permeability for lines of electric force, a synonym for the electro-static inductive capacity of an insulator; magnetic permeability, a synonym for conducting power for lines of magnetic force.
1896 F. Bedell Princ. Transformer 40 The reluctance, R, or magnetic resistance..varies..inversely as the cross-section and permeability.
1939 L. F. Bates Mod. Magn. ii. 67 Pure iron has an initial permeability of about 250.
1942 London, Edinb. & Dublin Philos. Mag. 7th Ser. 33 488 The universal constant 1/ac2 occurring in (12.2) has the value..1/107 ohm sec./m...and is called the permeability of empty space. Consistency practically compels us to call the constant μ/ac2 in (12.3) the permeability of the medium.
1944 London, Edinb., & Dublin Philos. Mag. 7th Ser. 35 83 Guggenheim has suggested the term permittivity for the fundamental quantity and specific inductive capacity or dielectric constant for the derived quantity. In conformity with the other suggestions in this paper it would be more uniform to adopt permittivity and relative permittivity... Similarly in the magnetic case we have permeability and relative permeability.
1962 D. R. Corson & P. Lorrain Introd. Electromagn. Fields vii. 284 The detailed shape of the magnetization curve and the maximum permeability achieved with a given sample of iron depend on the purity, the method of annealing, and on the thickness of the sheets.
1988 J. D. Barrow & F. J. Tipler Anthropic Cosmol. Princ. (rev. ed.) iv. 282 Maxwell's equations imply charge conservation, so a change in α is most conveniently interpreted as being due to a change in the permittivity or permeability of free space.
2003 Sci. Amer. Jan. 15/1 The refractive index of a substance is determined by two properties known as the electrical permittivity and the magnetic permeability.
Compounds
permeability tuner n. Electronics a tuner employing permeability tuning.
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1939 Wireless World 16 Feb. 151/2 A comparison between the performance of the permeability tuner and an efficient set of conventional variable-capacity-tuned iron-cored coils is of interest.
1977 Elektor Mar. 22/1 The variometer is an updated version of the old permeability tuners.
permeability tuning n. Electronics tuning in which the resonant frequency of a circuit is changed by moving a magnetic core into or out of a coil forming part of the circuit, so as to change its inductance.
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the world > matter > physics > electromagnetic radiation > electronics > electronic devices or components > operation of electronic devices > [noun] > tuning
tuning1899
permeability tuning1933
stagger tuning1953
slug tuning1957
1933 W. J. Polydoroff in Proc. IRE 21 694 The apparent inductance is increased to tune to lower frequencies by introducing a magnetic core into the field of the coil. As the core is inserted into the coil, more lines of the magnetic field are intercepted by the core, and, in effect, the average apparent permeability of the medium surrounding the coil increases from 1 (for air) to a certain maximum... For this reason, and for other reasons.., it is appropriate to describe this method as ‘Permeability Tuning’.
1968 Radio Communication Handbk. (ed. 4) iv. 35/2 Although permeability tuning has been most successfully used for many years by one major American company, the mechanical and electrical complications involved in band-switched receivers have resulted in little progress in this field by amateur constructors.
This entry has been updated (OED Third Edition, December 2005; most recently modified version published online March 2022).
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