ASTM E1142-97(2003)

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Designation:E1142–97 (Reapproved 2003)
Standard Terminology
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope decreasing temperature or increasing frequency, (D4092,
D-20), (1988).
1.1 This is a compilation of terms and corresponding
angular frequency, v—the number of radians per second
definitions commonly used in the study of thermophysical
traversedbyarotatingvectorthatrepresentsanyperiodically
properties. Terms that are generally understood or defined
varying quantity.
adequately in other readily available sources are either not
included or their sources identified.
DISCUSSION—Angular frequency, v, is equal to two p times the
1.2 A definition is a single sentence with additional infor- frequency, f.
mation included in a Discussion. It is reviewed every five
arrhenius equation—amathematicalrelationshipbetweenthe
years, and the year of the last review or revision is appended.
specific reaction rate and the temperature given as
1.3 Definitions identical to those published by another
–E/RT
k 5 Ae (1)
standardsorganizationorASTMCommitteeareidentifiedwith
the abbreviation of the name of the organization or the
where:
identifying document and ASTM Committee; for example,
kisthereactionrateconstant, Aisthefrequencyfactor, Eisthe
ICTAis the International Confederation for ThermalAnalysis.
energyofactivation, Risthegasconstant,and Tistheabsolute
1.4 Definitionsoftermsspecifictoaparticularfield(suchas
temperature, (1990).
dynamic mechanical measurements) are identified with an
beta (b) loss peak—in dynamic mechanical measurement,
italicized introductory phrase.
second discrete peak in damping curve below the melt, in
order of decreasing temperature or increasing frequency,
2. Referenced Documents
(D4092, D-20), (1988).
2.1 ASTM Standards:
boiling pressure—at a specific temperature, the value of the
D2160 Test Method for Thermal Stability of Hydraulic
vapor pressure of the liquid at which it is equal to the
Fluids
external pressure, (1988).
D 4092 Terminology Relating to Dynamic Mechanical
boiling temperature—at a specific pressure, the temperature
Measurements on Plastics
at which the vapor pressure of the liquid is equal to the
E7 Terminology Relating to Metallography
external pressure, (1988).
E473 Terminology Relating to Thermal Analysis
capacitance—that property of a system of conductors and
dielectrics that permits the storage of electrical charge when
3. Terminology
a potential difference exists between the conductors.
3.1 Terms and Definitions:
DISCUSSION—Capacitance is the ratio of a quantity of electric charge,
admittance, Y— the reciprocal of impedance.
Q, to a potential difference, V. A capacitance value is always positive.
alpha (a) loss peak—in dynamic mechanical measurement, The unit of capacitance is the farad, F, which is equivalent to one
coulomb per volt.
first peak in the damping curve below the melt, in order of
Celsius—designation of the degree on the International Prac-
tical Temperature Scale; also used for the name of the scale,
This terminology is under the jurisdiction of ASTM Committee E37 on
as “Celsius Temperature Scale.” Formerly (prior to 1948)
ThermalMeasurementsandarethedirectresponsibilityofSubcommitteeE37.03on
called“Centigrade.”TheCelsiustemperaturescaleisrelated
Nomenclature and Definitions.
to the International Kelvin Temperature Scale by the equa-
Current edition approved August 10, 1997. Published March 1998. Originally
published as E1142–88. Last previous edition E1142–96.
tion T =T − 273.16K, (1988).
c
Annual Book of ASTM Standards, Vol 05.01.
Centigrade—see Celsius.
Annual Book of ASTM Standards, Vol 08.02.
4 coeffıcient of expansion— see coefficient of linear thermal
Annual Book of ASTM Standards, Vol 03.01.
Annual Book of ASTM Standards, Vol 14.02. expansion.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1142–97 (2003)
coefficient of linear thermal expansion, a —change in cooling rate—average slope of the time-temperature curve
l
length, relative to the length of the specimen, accompanying taken over a specific time and temperature interval as the
a unit change of temperature, at a specified temperature, temperature is decreased, (1988).
(1988). critical curve—in a binary, or higher order, phase diagram, a
coefficient of volume thermal expansion a —for a solid or locus of points along which two or more phases exist in
v
liquid, the change in volume, relative to the volume of the stable thermodynamic equilibrium.
specimen, accompanying a change of temperature at a critical point—in a binary phase diagram, that specific value
specified temperature, (1988). of composition, temperature, pressure, or combinations
color temperature—temperature in degrees Kelvin (K) at thereof at which the phases of a heterogeneous equilibrium
whichablackbodymustbeoperatedtogiveacolorequalto become identical, (1989).
that of the source in question, (1988). critical pressure—that pressure at the critical point; (1990).
complex modulus,E*,G*, orK*—ratio of the stress to strain critical surface—in a ternary or higher order phase diagram,
where each is a factor that may be represented by a complex the area upon which the phases in equilibrium become
number as follows: E*=E8+iE9, G*=G8+iG9, and identical, (E7, E-4), (1988).
K*=K8+iK9. critical temperature—that temperature at the critical point,
(1990).
where:
E* = complex modulus, measured in tension or flexure,
crystal—solid composed of atoms, ions, or molecules, ar-
E8 = storage modulus, measured in tension or flexure,
ranged in a pattern which is periodic in three dimensions,
E9 = loss modulus, measured in tension or flexure,
(E7, E-4), (1988).
G* = complex modulus, measured in shear,
crystallinity—regular arrangement of the atoms of a solid in
G8 = storage modulus, measured in shear,
space, (1988).
G9 = loss modulus, measured in shear,
DISCUSSION—In most materials, this state is usually imperfectly
K* = complex modulus, measured in compression,
achieved.The crystalline regions (ordered regions) are submicroscopic
K8 = storage modulus, measured in compression
volumes in which there is more or less regularity of arrangement of the
K9 = loss modulus, measured in compression, and
i= –1 , measured in compression. component molecules.
=
The complex modulus may be measured in tension or
crystallite—crystalline grain not bounded by habit planes,
flexure, (E*), compression, (K*), or in shear, (G*), (D4092, (E7, E-4), (1988).
D-20), (1988).
crystallization—arrangement of previously disordered mate-
rialsegmentsofrepeatingpatternsintogeometricsymmetry,
complex shear compliance, J*—reciprocal of complex shear
modulus, where J* =1/G*, (D4092, D-20), (1988). (1988).
crystallization temperature—that temperature at which a
complex tensile compliance, D*—reciprocal of complex ten-
specimen undergoes crystallization upon cooling, (1988).
sile modulus, where D*=1/E*, (D4092, D-20), (1988).
Curie point—see Curie temperature.
composition—quantity of the components of a mixture; usu-
Curie temperature—temperature above which a ferromag-
ally expressed in terms of the weight percentage, or the
netic or ferroelectric material becomes paramagnetic, or
atomicpercentageofeachofthecomponentsinthemixture,
paraelectric, respectively (1997).
(E7, E-4), (1988).
conductivity, electrical (volume), s— the ratio of the current
DISCUSSION—There may be more than one if there are multiple
−2
density (A·cm ) through a specimen to the potential
materials.
gradient ( V/cm) in the same direction as the current.
damping—loss in energy, dissipated as heat, that results when
DISCUSSION—Conductivity is normally expressed in units (ohm·cm)
a material or material system is subjected to an oscillatory
−1, but the correct SI units are Siemen·m.
load or displacement, (D4092, D-20), (1988).
devitrification—crystallization of an amorphous substance,
congruent phases—those states of matter of unique composi-
(E7, E-4), (1988).
tion that co-exist at equilibrium at a single point in tempera-
dielectric constant— see permittivity, relative.
ture and pressure; for example, the two coexisting phases of
dielectric dissipation factor,D—theratioofthelossfactor, e9,
a two-phase equilibrium (E7, E-4), (1988).
to the absolute permittivity, e8,or
congruent transformation—an isothermal, or isobaric, phase
D 5e9/e8 (2)
changeinwhichbothofthephasesconcernedhavethesame
composition throughout the process; the order of a system
DISCUSSION—The dielectric dissipation factor is numerically equal to
becomes unary at a composition of congruency, (E7, E-4), thetangentofthedielectriclossangleandmaybereferredtoastheloss
tangent, tan d, or the cotangent of the phase angle, u.
(1988).
constitutional diagram—graphicalrepresentationofthecom-
dielectric loss angle—the angle whose tangent is the dissipa-
positions, temperatures, pressures, or combinations thereof
tion factor or arctan e9/e8.
at which the heterogeneous equilibria of a system occur,
DISCUSSION—It is also the difference between 90 degrees and the
(1988).
phase angle.
cooling curve—graphicalrepresentationofspecimentempera-
ture or temperature change as a function of time or decreas- differential thermocouple— see differential thermopile.
ing environment temperature, (1988). differential thermopile—a number of temperature sensors
E1142–97 (2003)
connectedinseries-opposingandarrangedsothatthereisan of freedom (F):P+F=C+2 (E7, E-4), (1989).
increase in output signal for a given temperature difference glass transition—reversible change in an amorphous material
between alternate junctions maintained at a reference tem- or in amorphous regions of a partially crystalline material,
perature and the measured temperature, (1989). from (or to) a viscous or rubbery condition to (or from) a
dipole relaxation time, g—the exponential decay time re- hard and relatively brittle one, (1988).
quired for the electric polarization of any point of a suitably
DISCUSSION—The glass transition generally occurs over a relatively
chargeddielectrictofallfromitsoriginalvalueto1/eofthat
narrowtemperatureregionandissimilartothesolidificationofaliquid
value, due to the loss of dipole orientation.
to a glassy state. Not only do hardness and brittleness undergo rapid
changes in this temperature region, but other properties, such as
DISCUSSION—Under conditions of an alternating applied field and in
coefficient of thermal expansion and specific heat capacity, also change
systemswithasingledipolerelaxationtime,itisequalto1/vattheloss
rapidly. This phenomenon sometimes is referred to as a second order
factor peak in cases where the peak is caused by a dipole mechanism.
transition,rubbertransition,orrubberytransition.Whenmorethanone
amorphous transition occurs in a material, the one associated with
dissipation factor— see tangent delta.
segmental motions of the backbone molecular chain, or accompanied
dissociation—as applied to heterogeneous equilibria, the
by the largest change in properties is usually considered to be the glass
transformationofonephaseintotwoormorenewphases,all
transition.
of different composition, (E7, E-4), (1988).
glass transition temperature—a temperature chosen to rep-
dynamic modulus—see complex modulus.
elasticity—thatpropertyofmaterialsthatcausesthemtoreturn resent the temperature range over which the glass transition
to their original form or condition after the applied force is takes place, (1989).
removed, (D4092, D-20), (1988).
DISCUSSION—The glass transition temperature can be determined
elastic modulus—see complex modulus and storage modu-
readily by observing the temperature region at which a significant
lus.
change takes place in some specific electrical, mechanical, thermal, or
enthalpy—a thermodynamic function defined by the equation
other physical property. Moreover, the observed temperature can vary
significantly depending on the property chosen for observation and on
H= U +PV where H is the enthalpy, U is the internal
details of the experimental technique (for example, heating rate,
energy, P is the pressure, and V the volume of the system.
frequency of test). Therefore, the observed Tg should be considered
DISCUSSION—At constant pressure the change in enthalpy measures
valid only for that particular technique and set of test conditions.
the quantity of heat exchanged by the system and its surrounding.
heat capacity—quantity of heat necessary to change the
equilibrium diagram— see constitutional diagram.
temperature of an entity, substance or system by one Kelvin
eutectic point—see eutectic.
of temperature.
eutectic—mixture of two or more substances which solidifies
DISCUSSION—The SI units of measurement are J/K (1995).
asawholewhencooledfromtheliquidstate,withoutchange
in composition, (1988).
impedance, Z—the ratio of the time dependent voltage, v (t),
across a circuit, a circuit element, or material to the time
DISCUSSION—Thetemperatureatwhichtheeutecticmixturesolidifies
dependent current, i (t), through it; that is:
is called the eutectic point. This temperature is constant for a given
composition, and represents the lowest melting point of the system.
Z 5 v~t!/i~t! (3)
Fahrenheit—designation of a degree on the Fahrenheit tem-
DISCUSSION—The impedance of a circuit, circuit element, or material
perature scale that is related to the International Practical
is a measure of its ability to oppose the transmission of an alternating
Temperature Scale by means of the equation: T =1.8 current. It is expressed in ohms. Its value depends on the angular
F
frequency, v, of the measurement.
T +32.
C
where:
invariant equilibrium—stable state among a number of
T is the temperature in degree Fahrenheit and T is the
F C
phases exceeding by two the number of components in the
temperature in degrees Celsius, (1988).
system and in which more of the external variables (pres-
freezing temperature— see crystallization temperature.
sure,temperatures,orconcentrations)maybevariedwithout
frequency, f—the number of cycles per unit time of periodic
causing a decrease in the number of phases present, (E7,
process.
E-4), (1988).
invariant point—point defined by the unique values of tem-
DISCUSSION—The unit is Hertz (Hz) which is equal to 1 cycle per/s.
perature, pressure, and concentrations in a system with the
frequency profile—in dynamic mechanical measurement, plot
maximum number of phases that can coexist in equilibri
...