ASTM E1142-22b
(Terminology)Standard Terminology Relating to Thermophysical Properties
Standard Terminology Relating to Thermophysical Properties
SCOPE
1.1 This is a compilation of terms and corresponding definitions commonly used in the study of thermophysical properties. Terms that are generally understood or defined adequately in other readily available sources are either not included or their sources identified.
1.2 A definition is a single sentence with additional information included in a Discussion.
1.3 Definitions of terms specific to a particular field (such as dynamic mechanical measurements) are identified with an italicized introductory phrase.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Designation: E1142 − 22b
Standard Terminology
1
Relating to Thermophysical Properties
This standard is issued under the fixed designation E1142; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope absolute pressure, n—pressure measured relative to zero
pressure corresponding to empty space.
1.1 This is a compilation of terms and corresponding
DISCUSSION—Absolute pressure is atmospheric pressure plus gage
definitions commonly used in the study of thermophysical
pressure.
properties. Terms that are generally understood or defined
adequately in other readily available sources are either not
activation energy (E), n—in chemical kinetics,theenergythat
included or their sources identified.
must be overcome in order for a chemical reaction to occur.
DISCUSSION—The term activation energy was introduced in 1889 by
1.2 A definition is a single sentence with additional infor-
SvanteArrhenius as a mathematical term in the eponymous, empirical
mation included in a Discussion.
relationship between temperature and reaction rate constant.
1.3 Definitionsoftermsspecifictoaparticularfield(suchas
admittance, Y, n—the reciprocal of impedance.
dynamic mechanical measurements) are identified with an
italicized introductory phrase.
alpha (α) loss peak, n—in dynamic mechanical measurement,
first peak in the damping curve below the melt, in order of
1.4 The values stated in SI units are to be regarded as
decreasing temperature or increasing frequency. E7
standard. No other units of measurement are included in this
standard.
amorphicity, n—a relative measure of amorphous material
1.5 This international standard was developed in accor-
content, expressed as a percent of the total material content.
dance with internationally recognized principles on standard-
angular frequency, ω, n—the number of radians per second
ization established in the Decision on Principles for the
traversedbyarotatingvectorthatrepresentsanyperiodically
Development of International Standards, Guides and Recom-
varying quantity.
mendations issued by the World Trade Organization Technical
DISCUSSION—Angular frequency, ω, is equal to two π times the
Barriers to Trade (TBT) Committee.
frequency, f.
2. Referenced Documents
anisotropic, adj—having different values for a property in
2
2.1 ASTM Standards:
different directions.
D4092 Terminology for Plastics: Dynamic Mechanical
anti-thixotropy, n—anincreaseoftheapparentviscosityunder
Properties
constant shear stress or shear rate followed by a gradual
E7Terminology Relating to Metallography
recovery when the stress or shear rate is reduced to zero.
E344Terminology Relating to Thermometry and Hydrom-
etry
Arrhenius equation, n—a mathematical relationship between
E2744Test Method for Pressure Calibration of Thermal
the specific reaction rate constant and the temperature given
Analyzers
as:
2E/RT
k 5 Ae (1)
3. Terminology
3.1 Definitions:
where:
k = the reaction rate constant,
1 A = the pre-exponential factor,
This terminology is under the jurisdiction of ASTM Committee E37 on
E = the energy of activation,
ThermalMeasurementsandarethedirectresponsibilityofSubcommitteeE37.03on
Nomenclature and Definitions.
R = the gas constant, and
Current edition approved March 1, 2022. Published June 2022. Originally
T = the absolute temperature.
approved in 1988. Last previous edition approved in 2022 as E1142–22a. DOI:
10.1520/E1142-22B.
atmospheric pressure, n—the pressure due to the weight of
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
the atmosphere. E2744
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
DISCUSSION—Atmospheric pressure varies with elevation above sea
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. level, acceleration due to gravity, and weather conditions.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E1142 − 22b
autocatalytic reaction, n—a chemical reaction in which a
E" = loss modulus, measured in tension or flexure,
product or reaction intermediate functions as a catalyst.
G* = complex modulus, measured in shear,
G' = storage modulus, measured in shear,
barometer, n—an instrument for measuring atmospheric pres-
G" = loss modulus, measured in shear,
sure.
K* = complex modulus, measured in compression,
beta (β) loss peak, n—in dynamic mechanical measurement,
K' = storage modulus, measured in compression
second discrete peak in damping curve below the melt, in K" = loss modulus, measured
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1142 − 22a E1142 − 22b
Standard Terminology
1
Relating to Thermophysical Properties
This standard is issued under the fixed designation E1142; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This is a compilation of terms and corresponding definitions commonly used in the study of thermophysical properties. Terms
that are generally understood or defined adequately in other readily available sources are either not included or their sources
identified.
1.2 A definition is a single sentence with additional information included in a Discussion.
1.3 Definitions of terms specific to a particular field (such as dynamic mechanical measurements) are identified with an italicized
introductory phrase.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D4092 Terminology for Plastics: Dynamic Mechanical Properties
E7 Terminology Relating to Metallography
E344 Terminology Relating to Thermometry and Hydrometry
E2744 Test Method for Pressure Calibration of Thermal Analyzers
3. Terminology
3.1 Definitions:
absolute pressure, n—pressure measured relative to zero pressure corresponding to empty space.
DISCUSSION—
Absolute pressure is atmospheric pressure plus gage pressure.
activation energy (E), n—in chemical kinetics, the energy that must be overcome in order for a chemical reaction to occur.
1
This terminology is under the jurisdiction of ASTM Committee E37 on Thermal Measurements and are the direct responsibility of Subcommittee E37.03 on
Nomenclature and Definitions.
Current edition approved Feb. 1, 2022March 1, 2022. Published February 2022June 2022. Originally approved in 1988. Last previous edition approved in 2022 as
E1142 – 22.E1142 – 22a. DOI: 10.1520/E1142-22A.10.1520/E1142-22B.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E1142 − 22b
DISCUSSION—
The term activation energy was introduced in 1889 by Svante Arrhenius as a mathematical term in the eponymous, empirical relationship between
temperature and reaction rate constant.
admittance, Y,n—the reciprocal of impedance.
alpha (α) loss peak, n—in dynamic mechanical measurement, first peak in the damping curve below the melt, in order of
decreasing temperature or increasing frequency. E7
amorphicity, n—a relative measure of amorphous material content, expressed as a percent of the total material content.
angular frequency, ω, n—the number of radians per second traversed by a rotating vector that represents any periodically
varying quantity.
DISCUSSION—
Angular frequency, ω, is equal to two π times the frequency, f.
anisotropic, adj—having different values for a property in different directions.
anti-thixotropy, n—an increase of the apparent viscosity under constant shear stress or shear rate followed by a gradual recovery
when the stress or shear rate is reduced to zero.
Arrhenius equation, n—a mathematical relationship between the specific reaction rate constant and the temperature given as:
2E/RT
k 5 Ae (1)
where:
k = the reaction rate constant,
A = the pre-exponential factor,
E = the energy of activation,
R = the gas constant, and
T = the absolute temperature.
atmospheric pressure, n—the pressure due to the weight of the atmosphere. E2744
DISCUSSION—
Atmospheric pressure varies with elevation above sea level, acceleration due to gravity, and weather conditions.
autocatalytic reaction, n—a chemical reaction in which a product or reaction intermediate functions as a catalyst.
barometer, n—an instrument for measuring atmospheric pressure.
beta (β) loss peak, n—in
...
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