# 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.
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 It might be outdated or ideologically biased.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.

## 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

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.

## 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 ?
By fitting the isotherms to the Langmuir equation, the resultant Qmax values ranged from 733.8 mg P[O.sub.4]-P [kg.sup.-1] (Kenya Aridisol, KA-A) to 3775 mg P[O.sub.4]-P [kg.sup.-1] (Costa Rica Oxisol, CRO-A) (Table 2), and the mean Qmax value for all soils was 2060 mg P[O.sub.4]-P [kg.sup.-1] (standard deviation (s.d.) = 767.7).
To determine the adsorption isotherms, six closed cells containing saline solutions were used in order to make the relative humidity of the internal environment, according to Greenspan (1977).
The essential features, separation factor (RL) of the Langmuir isotherm is expressed as:
Where "Kf" is Freundlich sorption coefficient and describer of isotherm slope is denoted by "n".
Dada, Langmuir, Freundlich, Temkin and Dubinin- Radushkevich Isotherms Studies of Equilibrium Sorption of Zn2+ Unto Phosphoric Acid Modified Rice Husk, IOSR-JAC, 3, 2278 (2012).
(2008), the Modified Halsey model is the best one to describe the accuracy of equilibrium isotherms in tropical plants, such as yellow mombin, and medicinal plants with high contents of volatiles.
Equilibrium Isotherms. Adsorption system can be designed by adsorption isotherms commonly known as equilibrium isotherms which represent the amount of solute adsorbed per unit weight of sorbent .
Comparisons between the experimental EMC, GAB, and BET isotherms are presented in Figures 3 and 4.
Freundlich isotherm: log [q.sub.e] = log [K.sub.F] + (1/n) log [C.sub.e] (4)
An inverse model based on artificial bee-colony (ABC) optimization method is proposed in this work for selection and configuration of appropriate sorption isotherms using the experimental sorption data.

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