isotherm


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isotherm,

line drawn on a map of a particular region of the earth's surface connecting points of equal temperature; each point reflects one temperature reading or an average of several readings over a period of time. The relative spacing of the isothermal lines indicates a temperature gradient, i.e., the amount of temperature change over a given distance.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Isotherm

 

an isogram of the temperature of air, water, or soil. Most commonly drawn are isothermal maps showing mean monthly air temperature over a number of years, mean temperature for any period of time, or the temperature at a definite moment of time. To eliminate the influence of elevation when drawing isotherms, temperature values are sometimes reduced to sea level, assuming that air temperature drops an average of 0.6 °C for each 100 m of increase in elevation.


Isotherm

 

a line on a phase diagram depicting a process occurring at constant temperature (an isothermic process). The equation of the isotherm of an ideal gas is pV = const, where p is the pressure and V is the volume of the gas. For a real gas the equation of an isotherm has a more complex character and becomes the equation for the isotherm of an ideal gas only at low pressures or high temperatures. On a pV diagram, at the point of intersection of the isotherm and the adiabatic curve the latter is steeper than the isotherm. The isotherms of ferromagnets in J, H, coordinates, where J is the magnetization and H is the magnetic field intensity, have a similar character.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

isotherm

[′ī·sə‚thərm]
(geophysics)
A line on a chart connecting all points of equal or constant temperature.
(thermodynamics)
A curve or formula showing the relationship between two variables, such as pressure and volume, when the temperature is held constant. Also known as isothermal.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

isotherm

isothermclick for a larger image
The line on the weather chart joining places of equal temperature. These are normally drawn for even 5°C intervals. These lines are customarily indicated in red.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved

isotherm

1. a line on a map linking places of equal temperature
2. Physics a curve on a graph that connects points of equal temperature
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Ahmad, "Adsorption isotherm, kinetic modeling and mechanism of 2, 4, 6-trichlorophenol on coconut husk-based activated carbon," Chemical Engineering Journal, vol.
The goodness of fit of GAB and BET was determined by testing the percentage root-mean-square error, RMSE, against the experimental isotherm data [32].
7 indicated linear plot thus obeying Langmuir isotherm that correspond to a saturated monolayer adsorption of the dye onto the homogeneous surface of NOAC.
The Langmuir isotherm is a special case of this model and can be derived by substituting a = 1.
The value of [R.sub.L] indicates the shape of the isotherm which is unfavourable ([R.sub.L] > 1), linear ([R.sub.L] = 1), favourable (0 < [R.sub.L] < 1), or irreversible ([R.sub.L] = 0).
This isotherm equation combines the characteristics of the Langmuir and Freundlich equations, thus showing a finite adsorption limit when the pressure is sufficiently high.
The Langmuir isotherm fits provided adequate representations of the P and DOC isotherms, with acceptable s.e.
This study aimed to analyze, by fitting mathematical models, the adsorption isotherms of acerola pulp powder obtained by spray-drying, and characterize the obtained powder as its hygroscopicity, caking, and solubility.
From Table 3, the correlation coefficient (R2) for Langmuir isotherm gave a good fit.
Data was linear for most of the samples and fitted well with Freundlich sorption Isotherm.