isochore

plural isochores

1. In general, a place or position with relevant parameters matching other places, as in having the same pressure, chemistry, population etc. Even within a single discipline the parameter might vary according to convenience e.g. in physics alone it might refer to velocity, volume, gravity, and many more. cf. contour, isopleth.

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   The numerical results are given from which the authors deduce the relation for constant volume and additional reasons are given for believing acetic acid (whose vapour density at ordinary temperatures is abnormal) to be a mixture of C₂H₄O₂ and C₄H₈0₄, the former preponderating as the temperature rises. The authors ask the Society for a name to designate lines connecting pressure and temperature at constant volume, and for which they suggested “isochore”...

   1887 Anonymous: Engineering, Volume 43 April 29th page 406

2. natural sciencesA line drawn on a graph showing the variation of the pressure of a constant volume of gas as it varies with temperature.

   1.3 shows the specific heat of argon measured along the critical isochore.

   1992, J M Yeomans, Statistical Mechanics of Phase Transitions, page 2

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   An isochore is a curve on a PVT diagram, the pressure and temperature being variable, the volume invariable.

   1916, William Cudmore McCullagh Lewis, A System of physical chemistry, volume 1, page 92

   Thus, an isochore transformation in this case is a transformation at constant volume.

   1956, Enrico Fermi, Thermodynamics, page 7

3. geographyA contour showing points of equal vertical thickness of strata; equal to an isopach if strata are horizontal.

   The isochore plan of the overburden thus obtained is then placed over the isochore plan of the seam.

   1964, Mineral Development in Assam: Symposium Volume, Assam (India) Directorate of Geology and Mining, page 205

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   Isochore maps of the sandstone bodies also indicate the presence of a number of channels flowing from the basin margin towards a central depression.

   1981, Coalfields of India, Geological Survey of India, page 125

4. biologyA sequence of DNA that has a reasonably constant proportion of pairs of guanine and cytosine bases, and is rich in genes.

   A model that accounts for the differential recognition of transgenes integrated at different chromosomal locations, is the isochore hypothesis.

   1998, Lindsey R Lindsey, Alan R Lindsey, Transgenic Plant Research, page 268