Nernstn.
/nəːnst/, U.S. /nərnst/ Physics and Chemistry.
1. attributive and in the genitive. Designating electrochemical theories and relations devised by Nernst; Nernst equation n. an equation relating the electromotive force of a cell to the reaction temperature, the standard free energy change of the reaction, and the activities of the products and reactants.
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1892 Philos. Trans. (Royal Soc.) A. 186 722 Nernst's theory of migration of the ions.
1897 Science 19 Mar. 485/1 Upon the Nernst theory this would produce a rapid fall in the electro-motive-force of the cell, until equilibrium is produced.
1905 Science 13 Jan. 51/2 The Nernst equation ignores the concentration of the undissociated salt, while the Helmholtz formulation does not.
1965 S. Schuldiner & T. B. Warner Potential of Platinum Electrode (NASA Techn. Rep.) 1 The Nernst equation relating hydrogen partial pressure and potential of a platinum electrode in acid solution has been experimentally verified.
2007 M. N. Levy & A. J. Pappano Cardiovascular Physiol. (ed. 9) ii. 17/2 The measured value of Vm..approximates that predicted by the Nernst equation for K+.
2. attributive and in the genitive. Designating a kind of incandescent lamp used esp. as a source of infrared radiation, in which an unenclosed filament or rod consisting of a mixture of rare earths and other metallic oxides (as magnesia or zirconia) is made hot and luminous by the passage of an electric current (after first being brought to a conducting state by external heating). Also: designating the filament itself. Esp. in Nernst glower, Nernst lamp. Now chiefly historical.
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the world > matter > light > artificial light > an artificial light > artificial light defined by light-source > [noun] > incandescent lamp > specific types of
Nernst lamp1898
turn-down1909
sun gun1960
1898 Science 24 June 856/2 The filament of Nernst's lamp is non-conducting when cold, but on being warmed it conducts, and then glows with a very brilliant light.
1898 Science 18 Nov. 689/1 (heading) The Nernst lamp.
1912 W. S. Franklin Electr. Lighting v. 134 There are five important kinds of glow lamps as follows:..(e) The Nernst lamp in which the glower is a small rod of porcelain-like material.
1950 L. J. Brady in M. G. Mellon Analyt. Absorption Spectrosc. viii. 444 One serious objection to the Nernst glower is the frequent mechanical failure of the source due to the poor bonding of the platinum leads to the element itself.
1952 Science 19 Dec. 687/1 A Nernst lamp or an ordinary tungsten lamp was suggested as a source of infrared light.
1965 J. R. Dyer Applic. Absorption Spectroscopy Org. Compounds iii. 24 A common light source for infrared radiation is the Nernst glower.
1980 Sci. Amer. May 123/2 The Welsbach mantle..proved to be a rich source of N rays. So did the Nernst glower.
2003 S. C. Singhal & K. Kendall High Temperature Solid Oxide Fuel Cells ii. 25 The light efficiency of the Nernst lamp exceeded that of the carbon filament lamp by nearly 80%.
3. attributive. Used with reference to a thermomagnetic effect investigated by Nernst, in which a temperature gradient in a metal subject to a magnetic field at right angles to the gradient gives rise to an electromotive force in a direction at right angles to both; esp. in Nernst effect.
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the world > matter > physics > electromagnetic radiation > electricity > electrically induced magnetism > [noun] > field > effect, theory
Poynting's theorem1893
Nernst effect1901
1901 M. G. Lloyd in Amer. Jrnl. Sci. 162 57 It has already been proposed† to call the galvano-magnetic temperature-difference, the thermo-magnetic temperature-difference, and the thermo-magnetic potential-difference by the respective names, Ettingshausen effect, Leduc effect and Nernst effect. [Note] †Thesis: The Transversal Thermo-magnetic Effect in Bismuth, M. G. Lloyd, Philadelphia, 1900; Beiblätter, 24, p. 1014.
1911 Physical Rev. 33 300 Both the Hall electromotive force and the Nernst electromotive force seem to be proportional to the intensity of magnetization in the plate rather than to the magnetic field.
1960 E. H. Putley Hall Effect & Related Phenomena ii. 28 The units for the Nernst coefficient are cm2 sec−1 (°K)−1 or m2 sec−1 (°K)−1.
1995 Physical Rev. B. 52 9727/2 We describe the magnetoresistivity, the Hall effect, the Nernst effect, and the magnetization in a polycrystalline sample.
2010 H. J. Goldsmid Introd. Thermoelectricity ii. 17 The Nernst effect also offers some advantages over the Seebeck effect in the detection of thermal radiation.
4. Nernst potential n. an electrical potential occurring in connection with the Nernst equation or the Nernst effect; spec. (for an ion passing across a membrane) the potential at which the diffusion force on the ion balances the electrical force acting on it.
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the world > matter > physics > atomic physics > ion > ionization > [noun] > potential
Nernst potential1907
ionization potential1913
ionization energy1914
critical potential1916
1907 Chem. Abstr. 1 535 A metal can be electrolytically deposited from the water solution of its salt upon a cathode if the requisite cathode potential is equal to or less than that necessary to set free hydrogen at the same metal... The Nernst potential formula can be used to express this.
1934 Jrnl. Physical Chem. 38 161 In treating the electrical potential across this type of metal–liquid interface, investigators have considered two potentials. The first is the Nernst potential obtained by the usual potentiometric determination of the potential difference by the use of a standard half-cell.
1973 Proc. National Acad. Sci. U.S.A. 70 1192/2 The induced conductance change is selective for cations, as a Nernst potential of about 50 mV was observed for a 10-fold sodium salt gradient and this was positive on the low-salt side of the membrane.
1974 V. B. Mountcastle et al. Med. Physiol. (ed. 13) I. i. 14/2 The result..is the well-known Nernst potential.
1990 EMBO Jrnl. 9 3891/2 In solutions containing 154 mM Cl− in the cytoplasm and 84 mM Cl− in the bath the zero current potential could be determined to be +15–18 mV, the Nernst potential for chloride.
2008 H. Yakabe in R. Bove & S. Ubertini Modeling Solid Oxide Fuel Cells x. 336 The calculated Nernst potentials include the concentration overpotential itself.
5. Nernst heat theorem n. (also Nernst's heat theorem, Nernst theorem, Nernst's theorem) [ < German Nernstsche Wärmetheorem (1906)] a theorem in thermodynamics which states that the change in entropy accompanying a chemical reaction between pure crystalline solids tends to zero as the temperature at which it occurs tends to absolute zero.Also called the third law of thermodynamics, esp. when formulated more generally in terms of the impossibility of reducing the temperature of a system to absolute zero in a finite number of steps.
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the world > matter > physics > mechanics > dynamics > thermodynamics > [noun] > specific theorems or principles
reciprocity theorem1878
Nernst heat theorem1912
Onsager's principle1945
1912 Chem. Abstr. 6 561 By a mathematical analysis based on Einstein's heat theory of sp. heats, and the Nernst heat theorem, G. reaches the conclusion [etc.].
1913 J. R. Partington Text-bk. Thermodynamics xvii. 484 The required information is furnished by a hypothesis put forward in 1906 by W. Nernst, and usually called by German writers ‘das Nernstsche Wärmetheorem’. We can refer to it without ambiguity as Nernst's Theorem.
1971 G. Socrates Thermodynamics & Statistical Mech. vii. 139 An alternative statement of Nernst's heat theorem is: It is impossible to reduce the temperature of any system to absolute zero in a finite number of operations.
1999 Nature 13 May 119/1 Nernst's heat theorem is indeed often called ‘the third law of thermodynamics’ in treatises on the subject, but just as often it is not given that distinction, because it isn't logically comparable to the all-encompassing first and second laws.
2009 M. Bordag et al. Adv. in Casimir Effect xiv. 360 We shall repeatedly apply Nernst's theorem to verify if the models under consideration are thermodynamically consistent.
This entry has been updated (OED Third Edition, September 2003; most recently modified version published online March 2022).
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