Part 3: Space and Time6 of 42 entries
3-5
angular measure, angular measurealpha
measure of a geometric figure, called plane angle, formed by two rays, called the sides of the plane angle, emanating…
3-6
rotational displacement, angular displacementvartheta
quotient of the traversed circular path length (t3-1.7) of a point in space during a rotation and its distance (t3-1.8)…
3-7
phase anglevarphi
angular measure (t3-5) between the positive real axis and the radius of the polar representation of the complex number…
3-8
solid angular measureii(Omega)
measure of a conical geometric figure, called solid angle, formed by all rays, originating from a common point, called…
3-16
rotationN
number of revolutions
3-25
logarithmic decrementLambda
product of damping coefficient (t3-24) and period duration (t3-14)
Part 4: Mechanics11 of 54 entries
4-4
relative mass density, relative densityd
quotient of mass density of a substance and mass density of a reference substance :
↑ 1ent
4-17.1
strainbb(ii(epsilon))
tensor (iso80000-2) quantity representing the deformation of matter caused by stress
4-17.2
relative linear strainepsilon
quotient of change in length (iso80000-3) of an object and its length (iso80000-3):
4-17.3
shear straingamma
quotient of parallel displacement (iso80000-3) of two surfaces of a layer and the thickness (iso80000-3) of the layer:
4-17.4
relative volume strainvartheta
quotient of change in volume (iso80000-3) of an object and its volume (iso80000-3):
4-18
Poisson numbermu
quotient of change in width (width is defined in iso80000-3) and change in length (length is defined in iso80000-3) of…
4-23.1
static friction coefficient, static friction factor, coefficient of static frictionmu_"s"
proportionality factor between the maximum magnitude of the tangential component of the static friction force (t4-9.3)…
4-23.2
kinetic friction factor, dynamic friction factormu
proportionality factor between the magnitudes of the kinetic friction force, (t4-9.4) and the normal component of the…
4-23.3
rolling resistance factorC_"rr"
proportionality factor between the magnitude of the tangential component and the magnitude of the normal component of…
4-23.4
drag coefficient, drag factorC_"D"
factor proportional to magnitude of the drag force (t4-9.6) of a body moving in a fluid, dependent on the shape and…
4-29
efficiency <mechanics>eta
quotient of output power (t4-27) from a system and input power (t4-27) to this system:
Part 5: Thermodynamics21 of 54 entries
5-2
Celsius temperaturet
temperature difference from the thermodynamic temperature of the ice point is called the Celsius temperature , which is…
5-9
thermal conductivitylambda
quotient of density of heat flow rate (t5-8) and thermodynamic temperature gradient that has the same direction as the…
5-10.1
coefficient of heat transferK
quotient of density of heat flow rate (t5-8) and thermodynamic temperature (t5-1) difference
5-10.2
surface coefficient of heat transferh
quotient of density of heat flow rate and the difference of the temperature at the surface and a reference temperature:…
5-16.1
specific heat capacityc
quotient of heat capacity and mass: where is heat capacity (t5-15) and is mass (iso80000-4)
↑ 1ent
5-16.2
specific heat capacity at constant pressurec_p
specific heat capacity (t5-16.1) at constant pressure (iso80000-4)
5-16.3
specific heat capacity at constant volumec_V
specific heat capacity (t5-16.1) at constant volume (iso80000-3)
5-16.4
specific heat capacity at saturated vapour pressurec_"sat"
specific heat capacity (t5-16.1) at saturated vapour pressure (iso80000-4)
5-17.1
ratio of specific heat capacitiesgamma
quotient of specific heat capacity at constant pressure and specific heat capacity at constant volume: where is…
5-17.2
isentropic exponent, isentropic expansion factorkappa
the negative of relative pressure change, divided by relative volume change, at constant entropy: where is volume…
5-19
specific entropys
quotient of entropy and mass: where is entropy (t5-18) and is mass (iso80000-4)
↑ 1ent
5-25.1
efficiency <thermodynamics>eta
quotient of work (iso80000-4) delivered by a heat engine and supplied heat: where is work (iso80000-4) and is heat…
5-25.2
maximum efficiencyeta_"max"
efficiency determined by the quotient of the temperatures of the hot source and the cold sink: where is the…
ent
5-26
specific gas constantR_"s"
quotient of the Boltzmann constant (iso80000-1) and the mass (iso80000-4) of the gas particle
5-29
mass ratio of water to dry matteru
quotient of mass of water and mass of dry matter: where is mass (iso80000-4) of water and is mass of dry matter
5-30
mass ratio of water vapour to dry gasr
quotient of mass of water vapour and mass of dry gas: where is mass (iso80000-4) of water vapour and is mass of dry gas
5-31
mass fraction of waterw_("H"_2"O")
quantity given by: where is mass ratio of water to dry matter (t5-29)
5-32
mass fraction of dry matterw_"d"
quantity given by: where is mass fraction of water (t5-31)
5-33
relative humidityvarphi
quotient of partial pressure of water vapour and partial pressure at its saturation: where is partial pressure…
5-34
relative mass concentration of vapourvarphi
quotient of mass concentration of water vapour and mass concentration at its saturation: where is mass concentration of…
5-35
relative mass ratio of vapourpsi
quotient of mass ratio of water vapour to dry gas and mass ratio of water vapour to dry gas at saturation: where is…
Part 6: Electromagnetism18 of 85 entries
6-15
relative permittivityepsilon_"r"
for linear media, quotient of permittivity (t6-14.2) and the electric constant (t6-14.1);
↑ 1
6-16
electric susceptibilitychi
for linear media, scalar quantity expressed by where is electric polarization (t6-7), is the electric constant…
6-27
relative permeabilitymu_"r"
for linear media, quotient of permeability (t6-26.2) and the magnetic constant (t6-26.1)
↑ 1
6-28
magnetic susceptibilitykappa
for linear media, proportionality constant between magnetization (t6-24) and magnetic field strength (t6-25)
6-32
magnetic vector potentialbb(ii(A))
vector quantity expressed by where is magnetic flux density (t6-21)
6-38
number of turns in a windingN
<in winding> number of turns
6-42.1
coupling factork
for inductive coupling between two inductive elements (numbered , ), scalar quantity given by where and are their…
6-42.2
leakage factorsigma
for inductive coupling between two inductive elements, scalar quantity given by where is the coupling factor (t6-42.1)
6-46
resistanceR
property of a resistive element, equal to the scalar quantity given by the quotient of voltage (t6-11.3) and electric…
6-48
phase differencevarphi
scalar quantity given by the difference between the phase angle (iso80000-3) of the voltage (t6-11.3) and the phase…
6-51.1
impedance, complex impedanceul Z
scalar quantity given by the quotient of voltage phasor (t6-50) and electric current phasor (t6-49)
6-51.3
resistanceR
real part of impedance (t6-51.1)
6-51.4
reactanceX
imaginary part of impedance (t6-51.1);
6-51.5
apparent impedanceZ
scalar quantity given by the quotient of RMS voltage (t6-11.3) and RMS electric current (t6-1)
6-53
quality factorQ
for non-radiating systems, where , scalar quantity given by where is impedance (t6-51.1), is resistance (t6-51.3), and…
6-54
loss factor, dissipation factord
scalar quantity given by the inverse of quality factor (t6-53);
6-55
loss angledelta
scalar quantity given by where is loss factor (t6-54)
6-58
power factorlambda
quotient of the active power (t6-56) and apparent power (t6-57);
Part 7: Light and Radiation29 of 66 entries
7-1.2
refractive indexn
quotient of speed of light in vacuum (iso80000-1) and speed of light in a medium (t7-1.1)
7-3.2
spectral radiant energy density in terms of wavelengthw_lambda
change of radiant energy density with wavelength, expressed by where is radiant energy density (t7-3.1) as a function…
7-5.2
spectral radiant intensityI_("e",lambda)
spectral density of radiant intensity, expressed by where is radiant intensity (t7-5.1) in terms of wavelength…
7-7.2
spectral irradianceE_("e",lambda)
density of irradiance with respect to wavelength, expressed by where is irradiance (t7-7.1) in terms of wavelength…
7-8.2
spectral radiant exitanceM_("e",lambda)
density of radiant exitance with respect to wavelength, expressed by where is radiant exitance (t7-8.1) in terms of…
7-9.2
spectral radiant exposureH_("e",lambda)
density of radiant exposure with respect to wavelength, expressed by where is radiant exposure (t7-9.1) in terms of…
7-10.1
luminous efficiency <specified photometric condition>V
quotient of radiant flux (t7-4.1) weighted by the spectral luminous efficiency (t7-10.2) and the corresponding radiant…
7-10.2
spectral luminous efficiency <specified photometric condition>V(lambda)
quotient of the radiant flux (t7-4.1) at wavelength and that at wavelength , such that both produce equally intense…
ent
7-19.1
photon number, number of photonsN_"p"
quotient of radiant energy and photon energy, expressed by where is radiant energy (t7-2.1), is the Planck constant…
ent
7-26.1
tristimulus values for the CIE 1931 standard colorimetric observerX, Y, Z
amounts of the three reference colour stimuli in the CIE 1931 standard colorimetric system, required to match the…
ent
7-26.2
tristimulus values for the CIE 1964 standard colorimetric observerX_(10), Y_(10), Z_(10)
amounts of the three reference colour stimuli in the CIE 1964 standard colorimetric system, required to match the…
ent
7-27.1
CIE colour-matching functions for the CIE 1931 standard colorimetric observerbar x(lambda), bar y(lambda), bar z(lambda)
functions , , in the CIE 1931 standard colorimetric system
7-27.2
CIE colour-matching functions for the CIE 1964 standard colorimetric observerbar x_(10)(lambda), bar y_(10)(lambda), bar z_(10)(lambda)
functions , , in the CIE 1964 standard colorimetric system
7-28.1
chromaticity coordinates in the CIE 1931 standard colorimetric systemx, y, z
coordinates expressing the quotients of each of a set of three tristimulus values for the CIE 1931 standard…
7-28.2
chromaticity coordinates in the CIE 1964 standard colorimetric systemx_(10), y_(10), z_(10)
coordinates expressing the quotients of each of a set of three tristimulus values for the CIE 1964 standard…
7-30.1
emissivityepsilon
quotient of the radiant exitance of a radiator and the radiant exitance of a Planckian radiator at the same…
7-30.2
emissivity at a specified wavelengthepsilon(lambda)
quotient of the radiant exitance of a radiator at a specified wavelength and the radiant exitance of a Planckian…
7-31.1
absorptancealpha
quotient of absorbed radiant flux and incident radiant flux, expressed by where is absorbed radiant flux (t7-4.1) and…
7-31.2
luminous absorptancealpha_"v"
quotient of absorbed luminous flux and incident luminous flux, expressed by where is absorbed luminous flux (t7-13) and…
ent
7-31.3
reflectancerho
quotient of reflected radiant flux and incident radiant flux, expressed by where is reflected radiant flux (t7-4.1) and…
7-31.4
luminous reflectancerho_"v"
quotient of reflected luminous flux and incident luminous flux, is expressed by where is reflected luminous flux…
ent
7-31.5
transmittancetau
quotient of transmitted radiant flux and incident radiant flux, expressed by where is transmitted radiant flux (t7-4.1)…
7-31.6
luminous transmittancetau_"v"
quotient of transmitted luminous flux and incident luminous flux, expressed by where is transmitted luminous flux…
ent
7-32.1
transmittance optical density, optical density, transmittance density, decadic absorbanceD
logarithm to base 10 of the reciprocal of the transmittance, (t7-31.5)
7-32.2
Napierian absorbanceA_"n"
natural (Napierian) logarithm of the reciprocal of the transmittance, (t7-31.5)
7-33.1
radiance factorbeta_"e"
quotient of the radiance of a surface element in a specified direction and the radiance of the perfect reflecting…
7-33.2
luminance factorbeta_"v"
quotient of the luminance of a surface element in a specified direction and the luminance of the perfect reflecting…
7-34
reflectance factorR
quotient of the flux reflected in the directions delimited by a given cone with apex at a surface element and the flux…
7-36.2
mass absorption coefficient <radiometry>alpha_"m"
quotient of the linear absorption coefficient (t7-35.2), , and the mass density (iso80000-4), , of the medium
ent
Part 8: Acoustics4 of 18 entries
8-1
logarithmic frequency rangeG
quantity given by: where and are two frequencies (iso80000-3)
8-14
sound pressure levelL_p
quantity given by: where is the root-mean-square sound pressure in the time domain and is the reference value of sound…
8-15
sound power levelL_P
quantity given by: where is the magnitude of the time-averaged sound power (t8-9) and is the reference value of sound…
8-16
sound exposure levelL_E
quantity given by: where is sound exposure (t8-11) and is the reference value of sound exposure
Part 9: Physical Chemistry34 of 62 entries
9-1
number of entitiesN(X)
number of elementary entities of kind in a system
ent
9-3
relative atomic massA_"r"("X")
quotient of the average mass (iso80000-4) of atom and the unified atomic mass (iso80000-10)
↑ 1ent
9-7
molar heat capacityC_"m"
quotient of heat capacity (iso80000-5) and amount of substance (t9-2):
↑ 1ent
9-8
molar entropyS_"m"
quotient of entropy (iso80000-5) and amount of substance (t9-2):
↑ 1ent
9-11
mass fractionw_"X"
for substance in a mixture, quotient of mass (iso80000-4) of substance and total mass of the mixture:
ent
9-13
amount-of-substance fraction, mole fractionx_"X"
for substance in a mixture, quotient of amount of substance (t9-2) of and total amount of substance (t9-2) in the…
ent
9-18
absolute activitylambda_"X"
for substance , exponential of quotient of chemical potential of substance (t9-17), and product of molar gas constant…
ent
9-22
activity factorf_"X"
for substance in a liquid or a solid mixture, quotient of absolute activity (t9-18) of substance and the product of…
ent
9-23
standard absolute activity <in a mixture>lambda_"X"^(⊖)
for substance in a liquid or a solid mixture, absolute activity (t9-18) of the pure substance at the same temperature…
ent
9-24
activity of solute, relative activity of solutea_"X"
for a solute in a solution, quantity proportional to the absolute activity, (t9-18), the proportionality factor, which…
ent
9-25
activity coefficientgamma_"B"
for a solute in a solution, quotient of activity of solute (t9-24), and quotient of the molality (t9-15) of substance…
ent
9-26
standard absolute activity <in a solution>lambda_"B"^(⊖)
for a solute in a solution: where denotes summation over all solutes, is a standard pressure (iso80000-4), is standard…
ent
9-27.1
activity of solvent, relative activity of solventa_"A"
for the solvent in a solution, quotient of the absolute activity of substance , (t9-18), and that, , of the pure…
ent
9-27.2
osmotic factor of solvent, osmotic coefficient of solvent Avarphi
quantity given by: where is the molar mass (t9-4) of the solvent , denotes summation over all the solutes, is the…
ent
9-27.3
standard absolute activity of solvent <in a dilute solution>lambda_"A"^(⊖)
for solvent , standard absolute activity (t9-23) of the pure substance at the same temperature (iso80000-5) and at a…
ent
9-29
stoichiometric number of substancenu_"B"
for substance , an integer number or a simple fraction, being negative for a reactant and positive for a product,…
ent
9-32
standard equilibrium constant, thermodynamic equilibrium constantK^(⊖)
for a chemical reaction, product for all substances of standard absolute activity of substance (t9-26) in power of…
ent
9-33
equilibrium constant <pressure basis>K_p
for gases, product for all substances of partial pressure of substance (t9-19) in power of its stoichiometric number…
ent
9-34
equilibrium constant <concentration basis>K_c
for solutions, product for all substances of concentration of substance (t9-9.1) in power of its stoichiometric number…
ent
9-35.1
microcanonical partition functionii(Omega)
number of all quantum states consistent with given energy (iso80000-4), volume (iso80000-3), and external fields:
9-35.2
canonical partition functionZ
sum over quantum states of energy (iso80000-4), expressed by: where is the Boltzmann constant (iso80000-1), and is…
9-35.3
grand-canonical partition function, grand partition functionii(Xi)
sum of canonical partition function for the given number of particles multiplied by absolute activities (t9-18) of…
ent
9-35.4
molecular partition function, partition function of a moleculeq
quantity given by: where is the energy (iso80000-5) of the -th level of the molecule consistent with given volume…
ent
9-36.1
statistical weight of subsystemg
number of different microstates in a subsystem
9-36.2
degeneracy, multiplicityg
for quantum level, statistical weight of that level
9-37.1
molar gas constantR
product of the Boltzmann constant (iso80000-1) and the Avogadro constant (iso80000-1)
9-37.2
specific gas constantR_"s"
quotient of molar gas constant (t9-37.1) and molar mass (t9-4) , i.e.
9-40.1
thermal diffusion ratiok_T
in a steady-state of a binary mixture in which thermal diffusion occurs, proportionality factor between gradient of the…
ent
9-40.2
thermal diffusion factoralpha_T
quotient of the thermal diffusion ratio (t9-40.1), and the product of the local amount-of-substance fractions , (t9-13)…
ent
9-43
degree of dissociation, dissociation fractionalpha
in a sample, quotient of the number of dissociated molecules and the total number of molecules:
ent
9-46
transport number of the ion B, current fraction of the ion Bt_"B"
for the ion , quotient of electric current (iec80000-6) carried by the ion and total electric current (iec80000-6) in…
ent
9-47
angle of optical rotationalpha
angle through which plane-polarized light is rotated clockwise, as seen when facing the light source, in passing…
ent
9-48
molar optical rotatory poweralpha_n
angle of optical rotation (t9-47), multiplied by the quotient of cross-sectional area (iso80000-3) of a linearly…
ent
9-49
specific optical rotatory poweralpha_m
angle of optical rotation (t9-47), multiplied by the quotient of cross-sectional area (iso80000-3) of a linearly…
Part 10: Atomic and Nuclear35 of 125 entries
10-1.1
atomic number, proton numberZ
number of protons in an atomic nucleus
ent
10-1.2
neutron numberN
number of neutrons in an atomic nucleus
ent
10-1.3
nucleon number, mass numberA
number of nucleons in an atomic nucleus
ent
10-5.2
charge number, ionization numberc
for a particle, quotient of the electric charge (iec80000-6) and the elementary charge (iso80000-1)
10-13.1
quantum numberN
number describing a particular state of a quantum system
ent
10-13.2
principal quantum numbern
atomic quantum number related to the number of radial nodes of one-electron wave functions
ent
10-13.3
orbital angular momentum quantum numberl
atomic quantum number related to the orbital angular momentum of a one-electron state
ent
10-13.4
magnetic quantum numberm
atomic quantum number related to the component , or , of the orbital, total, or spin angular momentum
10-13.5
spin quantum numbers
characteristic quantum number of a particle, related to its spin (t10-10), : where is the reduced Planck constant…
10-13.6
total angular momentum quantum numberj
quantum number in an atom describing the magnitude of total angular momentum (t10-11)
ent
10-13.7
nuclear spin quantum numberI
quantum number related to the total angular momentum (t10-11), , of a nucleus in any specified state, normally called…
ent
10-13.8
hyperfine structure quantum numberF
quantum number of an atom describing the inclination of the nuclear spin with respect to a quantization axis given by…
ent
10-14.1
Landé factor, g factor of atomg
quotient of the magnetic dipole moment of an atom, and the product of the total angular momentum quantum number and the…
ent
10-14.2
g factor of nucleus or nuclear particleg
quotient of the magnetic dipole moment of an atom, and the product of the nuclear spin quantum number and the nuclear…
ent
10-22.1
relative mass excessii(Delta)_"r"
quotient of mass excess and the unified atomic mass constant: where is mass excess (t10-21.1), and is the unified…
↑ 1
10-22.2
relative mass defectB_"r"
quotient of mass defect and the unified atomic mass constant: where is mass defect (t10-21.2), and is the unified…
↑ 1
10-23.1
packing fractionf
quotient of relative mass excess and the nucleon number: where is relative mass excess (t10-22.1), and is the nucleon…
10-23.2
binding fractionb
quotient of relative mass defect and the nucleon number: where is relative mass defect (t10-22.2), and is the nucleon…
10-35
internal conversion factoralpha
quotient of the number of internal conversion electrons and the number of gamma quanta emitted by the radioactive atom…
ent
10-36
particle emission rateN
differential quotient of with respect to time, where is the number of particles being emitted from an infinitesimally…
ent
10-41
direction and energy distribution of cross section <atomic physics>sigma_(ii(Omega),E)
partial differential quotient of with respect to solid angle and energy, where is the cross section (t10-38.1) for…
10-59
total ionizationN_"i"
quotient of the total mean charge of all positive ions produced by an ionizing charged particle along its entire path…
10-61
mobilitymu
quotient of average drift speed (iso80000-3) imparted to a charged particle in a medium by an electric field, and the…
10-68
resonance escape probabilityp
in an infinite medium, the probability that a neutron slowing down will traverse all or some specified portion of the…
ent
10-69
lethargyu
for a neutron of kinetic energy (iso80000-4): where is a reference energy
ent
10-70
average logarithmic energy decrementzeta
average value of the increase in lethargy (t10-69) in elastic collisions between neutrons and nuclei whose kinetic…
10-74.1
neutron yield per fissionnu
average number of fission neutrons, both prompt and delayed, emitted per fission event
ent
10-74.2
neutron yield per absorptioneta
average number of fission neutrons, both prompt and delayed, emitted per neutron absorbed in a fissionable nuclide or…
ent
10-75
fast fission factorvarphi
in an infinite medium, the quotient of the mean number of neutrons produced by fission due to neutrons of all energies…
10-76
thermal utilization factorf
in an infinite medium, the quotient of the number of thermal neutrons absorbed in a fissionable nuclide or in a nuclear…
10-77
non-leakage probabilityii(Lambda)
probability that a neutron will not escape from the reactor during the slowing-down process or while it diffuses as a…
ent
10-78.1
multiplication factork
quotient of the total number of fission or fission-dependent neutrons produced in the duration of a time interval and…
10-78.2
infinite multiplication factork_(oo)
multiplication factor (t10-78.1) for an infinite medium or for an infinite repeating lattice
ent
10-82
quality factor <ionizing radiation>Q
factor in the calculation and measurement of dose equivalent (t10-83.1), by which the absorbed dose (t10-81.1) is to be…
10-89
exposure ratedot X
differential quotient of the exposure (t10-88) with respect to time (iso80000-3):
Part 11: Characteristic Numbers115 of ? entries
11-4.1
Reynolds numberRe
quotient of inertial forces and viscous forces in a fluid flow, expressed by ; where is mass density (iso80000-4), is…
11-4.2
Euler numberEu
relationship between pressure drop in a flow and the kinetic energy per volume for flow of fluids in a pipe, expressed…
11-4.3
Froude numberFr
quotient of a body's inertial forces and its gravitational forces for flow of fluids, expressed by ; where is speed…
11-4.4
Grashof numberGr
quotient of buoyancy forces due to thermal expansion which results in a change of mass density and viscous forces for…
11-4.5
Weber numberWe
relation between inertial forces and capillary forces due to surface tension at the interface between two different…
11-4.6
Mach numberMa
quotient of the speed of flow and the speed of sound, expressed by ; where is speed (iso80000-3) of the body, and is…
11-4.7
Knudsen numberKn
quotient of free path length of a particle and a characteristic length, expressed by ; where is mean free path…
11-4.8
Strouhal number, Thomson numberSr
relation between a characteristic frequency and a characteristic speed for unsteady flow with periodic behaviour,…
11-4.9
drag coefficientc_"D"
relation between the effective drag force and inertial forces for a body moving in a fluid, expressed by ; where is…
11-4.10
Bagnold numberBg
quotient of drag force and gravitational force for a body moving in a fluid, expressed by ; where is drag coefficient…
11-4.11
Bagnold number <solid particles>Ba_2
quotient of drag force and viscous force in a fluid transferring solid particles, expressed by ; where is mass density…
11-4.12
lift coefficientc_"l"
quotient of the lift force available from a wing at a given angle and the inertial force for a wing shaped body moving…
11-4.13
thrust coefficientc_"t"
quotient of the effective thrust force available from a propeller and the inertial force in a fluid, expressed by ;…
11-4.14
Dean numberDn
relation between centrifugal force and inertial force, for flows of fluids in curved pipes, expressed by ; where is…
11-4.15
Bejan numberBe
quotient of mechanical work and frictional energy loss in fluid dynamics in a pipe, expressed by ; where is drop of…
11-4.16
Lagrange numberLg
quotient of mechanical work and frictional energy loss in fluid dynamics in a pipe, expressed by ; where is length…
11-4.17
Bingham number, plasticity numberBm
quotient of yield stress and viscous stress in a viscous material for flow of viscoplastic material in channels,…
11-4.18
Hedström numberHe
quotient of yield stress and viscous stress of a viscous material at flow limit for visco-plastic material in a…
11-4.19
Bodenstein numberBd
mathematical expression of the transfer of matter by convection in reactors with respect to diffusion, ; where is speed…
11-4.20
Rossby number, Kiebel numberRo
quotient of inertial forces and Coriolis forces in the context of transfer of matter in geophysics, expressed by ;…
11-4.21
Ekman numberEk
quotient of viscous forces and Coriolis forces in the context of transfer of matter for the flow of a rotating fluid,…
11-4.22
elasticity numberEl
relation between relaxation time and diffusion time in viscoelastic flows, expressed by ; where is relaxation time…
11-4.23
Darcy friction factor, Moody friction factorf_"D"
representation of pressure loss in a pipe due to friction within a laminar or turbulent flow of a fluid in a pipe,…
11-4.24
Fanning numberf_"n"
relation between shear stress and dynamic pressure in the flow of a fluid in a containment, expressed by ; where is…
11-4.25
Goertler number, Goertler parameterGo
characterization of the stability of laminar boundary layer flows in transfer of matter in a boundary layer on curved…
11-4.26
Hagen numberHg
generalization of the Grashof number for forced or free convection in laminar flow, expressed by ; where is mass…
11-4.27
Laval numberLa
quotient of speed and the (critical) sound speed at the throat of a nozzle, expressed by ; where is speed (iso80000-3),…
11-4.28
Poiseuille numberPoi
quotient of propulsive force by pressure and viscous force for a flow of fluids in a pipe, expressed by ; where is drop…
11-4.29
power numberPn
quotient of power consumption by agitators due to drag and rotational inertial power in fluids, expressed by ; where is…
11-4.30
Richardson numberRi
quotient of potential energy and kinetic energy for a falling body, expressed by ; where is acceleration of free fall…
11-4.31
Reech numberRee
relation between the speed of an object submerged in water relative to the water, and wave propagation speed, expressed…
ent
11-4.32
Stokes number <time-related>Stk
quotient of friction and inertia forces for particles in a fluid or in a plasma, expressed by ; where is relaxation…
11-4.33
Stokes number <vibrating particles>Stk_1
quotient of friction and inertia forces for the special case of particles vibrating in a fluid or plasma, expressed by…
11-4.34
Stokes number <rotameter>, power coefficient <rotameter>Stk_2
Stokes number for calibration of rotameters metering vertical flows of fluids by means of a floating body, expressed by…
11-4.35
Stokes number <gravity>Stk_3
relation between viscous forces and gravity forces for particles falling in a fluid, expressed by ; where is…
11-4.36
Stokes number <drag>Stk_4
quotient of drag force and internal friction forces for particles dragged in a fluid ; where is drag force…
11-4.37
Laplace number, Suratman numberLa
relation between capillary forces and viscous forces when characterizing free surface flow, expressed by ; where is…
11-4.38
Blake numberBl
relation between inertial forces and viscous forces in a porous material, expressed by ; where is speed (iso80000-3) of…
11-4.39
Sommerfeld numberSo
relation between viscous force and load force in a lubrication boundary, expressed by ; where is dynamic viscosity…
11-4.40
Taylor number <momentum transfer>Ta
relation between centrifugal force and viscous force of a rotating shaft, expressed by ; where is angular velocity…
11-4.41
Galilei numberGa
relation between gravitational force and viscous force in fluid films flowing over walls, expressed by ; where is…
11-4.42
Womersley numberWo
relation between inertial forces and viscous forces in oscillating flows of fluids in pipes, expressed by ; where is…
11-5.1
Fourier number <heat transfer>Fo
relation between heat conduction rate and the rate of thermal energy storage in a body for conductive heat transfer…
11-5.2
Péclet number <heat transfer>Pe
relation between convective heat transfer rate and conductive heat transfer rate, expressed by ; where is speed…
11-5.3
Rayleigh numberRa
relation between buoyancy forces due to thermal expansion and viscous forces in free convection in buoyancy driven flow…
11-5.4
Froude number <heat transfer>Fr**
quotient of gravitational forces and thermodiffusion forces for heat transfer in forced convection of fluids, expressed…
11-5.5
Nusselt number <heat transfer>N u
relation between the internal thermal resistance of a body and its surface thermal resistance in a body transferring…
11-5.6
Biot number <heat transfer>Bi
special case of the Nusselt number for heat transfer (item t11-5.5) in case of conductive heat transfer in a solid…
11-5.7
Stanton number <heat transfer>St
relation between heat transfer into a fluid from a surface and its heat transfer by convection, expressed by ; where is…
11-5.8
j-factor <heat transfer>, heat transfer factor, Colburn numberj
relation between heat transfer and mass transfer in a fluid, expressed by ; where is coefficient of heat transfer…
11-5.9
Bejan number <heat transfer>Be_1
quotient of mechanical work and frictional and thermal diffusion energy losses for a forced flow, expressed by ; where…
11-5.10
Bejan number <entropy>Be_S
efficiency of heat transfer by a fluid, expressed by ; where is entropy generation contributed by heat transfer, and is…
11-5.11
Stefan number <phase transition>Ste
relation between heat content and latent heat content in a binary mixture undergoing a phase transition, expressed by ;…
11-5.12
Brinkman numberBr
relation between heat produced by viscosity and heat conducted from a wall adjacent to a fluid moving relative to it,…
11-5.13
Clausius numberCl
relation between energy transfer associated with fluid momentum and energy transfer by thermal conduction in forced…
11-5.14
Carnot numberCa
theoretical maximum efficiency (iso80000-5) of a Carnot cycle operating between temperature reservoirs ; where is…
ent
11-5.15
Eckert number, Dulong numberEc
relation between the kinetic energy of a flow and its enthalpy change in fluid dynamics exhibiting dissipation,…
11-5.16
Graetz number <heat transfer>Gz
relation between heat transferred by convection and heat transferred by conduction in a laminar flow in a pipe,…
11-5.17
heat transfer numberK_Q
relation between heat transferred by a flow and its kinetic energy, expressed by ; where is heat flow rate…
11-5.18
Pomerantsev number <heat transfer>Po
relation between heat generated in a body and conducted heat in the body, expressed by ; where is (constant) volumic…
11-5.19
Boltzmann numberBz
relation between convective heat and radiant heat for a fluid in a channel, expressed by ; where is mass density…
11-5.20
Stark number, DEPRECATED: Stefan number, DEPRECATED: Biot radiation numberSk
relation between radiant heat and conductive heat multiplied by the relative temperature difference for a body,…
11-6.1
Fourier number <mass transfer>Fo**
relation between diffusive mass transfer within a given duration and mass storage rate in transient mass transfer,…
11-6.2
Péclet number <mass transfer>, Bodenstein number <mass transfer>Pe**
relation between advective mass transfer rate and longitudinal diffusive mass transfer rate for mass transfer in…
11-6.3
Grashof number <mass transfer>Gr**
relation between buoyancy forces and viscous forces in natural convection of fluids, expressed by ; where is…
ent
11-6.4
Nusselt number <mass transfer>N u**
relation between mass flux at an interface and specific flux by pure molecular diffusion in a layer of thickness for…
11-6.5
Stanton number <mass transfer>St**
relation between mass transfer perpendicular to the surface of a fluid flow and mass transfer parallel to the surface…
11-6.6
Graetz number <mass transfer>Gz**
quotient of advective mass transfer rate and radial diffusive mass transfer rate for mass transfer in pipes, expressed…
11-6.7
mass transfer factor, j-factor <mass transfer>j**
relation between mass transfer perpendicular to the surface of a fluid and mass transfer parallel to the surface in an…
11-6.8
Atwood numberAt
scaled density difference of heavier and lighter fluids, expressed by ; where is density of heavier fluid, and is…
11-6.9
Biot number <mass transfer>Bi**
relation between mass transfer rate at the interface and mass transfer rate in the interior of a body, expressed by ;…
11-6.10
Morton numberMo
quotient of gravitational forces and viscous forces for gas bubbles in a liquid, or liquid drops in a gas, expressed by…
11-6.11
Bond number, Eötvös numberBo
quotient of inertial force and capillary force for gas bubbles or liquid drops in a fluid, expressed by ; where is the…
11-6.12
Archimedes numberAr
quotient of buoyancy forces and viscous forces in fluids motion due to density differences for a body in a fluid,…
11-6.13
expansion numberEx
quotient of buoyancy force and inertial force in moving fluids due to density differences for gas bubbles rising in a…
11-6.14
Marangoni numberMg
quotient of heat transferred by Marangoni convection and heat transferred by thermal diffusivity in thermo-capillary…
11-6.15
Lockhart-Martinelli parameterLp
quotient of mass flow rates multiplied by the square root of density in a two-phase flow, expressed by ; where is…
11-6.16
Bejan number <mass transfer>Be**
quotient of mechanical work and frictional and diffusion energy loss in viscous flow of fluids in pipes, expressed by ;…
11-6.17
cavitation numberCa
quotient of the excess of local static head over vapour pressure head and velocity head for fast flow in liquids,…
11-6.18
absorption numberAb
relation between mass flow rate and surface area for gas absorption at wetted walls, expressed by ; where is the mass…
11-6.19
capillary numberCa
quotient of gravitational forces and capillary forces for fluids in narrow pipes, expressed by ; where is diameter…
11-6.20
dynamic capillary numberCa**
quotient of viscous force and capillary force acting across an interface between a liquid and a gas, or between two…
11-7.1
Prandtl numberPr
quotient of kinematic viscosity and thermal diffusivity for a fluid, expressed by ; where is kinematic viscosity…
11-7.2
Schmidt number, DEPRECATED: Colburn numberSc
quotient of kinematic viscosity and diffusion coefficient for a fluid, expressed by ; where is kinematic viscosity…
11-7.3
Lewis numberLe
quotient of thermal diffusivity and diffusion coefficient for heat transfer in a fluid, expressed by ; where is thermal…
11-7.4
Ohnesorge numberOh
relation between viscous force and the square root of the product of inertia force and capillary force for atomization…
11-7.5
Cauchy number, aeroelasticity parameterCy
relation between inertia forces and compression forces in compressible fluids, expressed by ; where is mass density…
11-7.6
Hooke numberHo_2
relation between inertia forces and linear stress forces in elastic fluids, expressed by ; where is mass density…
11-7.7
Weissenberg numberWi
product of time derivative of shear rate and relaxation time in viscoelastic flows, expressed by ; where is time…
11-7.8
Deborah numberDe
quotient of relaxation time of viscoelastic fluids and observation duration in rheology of viscoelastic fluids,…
11-7.9
Lorentz numberLo
quotient of electrical conductivity and thermal conductivity, expressed by ; where is electrical conductivity…
11-7.10
compressibility numberZ
quotient of isothermal compressibility (iso80000-5) of a gas and that of an ideal gas, expressed by ; where is pressure…
11-8.1
Reynolds magnetic numberRm
relation between inertial force and magneto-dynamic viscous force in an electrically conducting fluid, expressed by ;…
11-8.2
Batchelor numberBt
relation between inertia and magneto-dynamic diffusion in an electrically conducting liquid, expressed by ; where is…
11-8.3
Nusselt electric numberNe
relation between convective current and diffusive current of ions in electrochemistry, expressed by ; where is speed…
11-8.4
Alfvén number, Mach magnetic number, Kárman numberAl
relation between speed of a plasma and the Alfvén wave speed, expressed by ; where is speed (iso80000-3), is magnetic…
ent
11-8.5
Hartmann numberHa
relation between magnetically induced stress and hydrodynamic shear stress in an electrically conducting fluid,…
11-8.6
Cowling number <magnetism>, Euler magnetic numberCo
quotient of magnetic and kinematic energy density in a plasma, expressed by ; where is magnetic flux density…
11-8.7
Stuart electrical numberSe
quotient of electric energy density and kinematic energy density in a plasma, expressed by ; where is electric…
11-8.8
magnetic pressure numberN_(m p)
quotient of gas pressure and magnetic pressure in a gas or plasma, expressed by ; where is pressure (iso80000-4), is…
11-8.9
Chandrasekhar numberQ
quotient of Lorentz force and viscous force in magnetic convection in a fluid, expressed by ; where is magnetic flux…
11-8.10
Prandtl magnetic numberPr_"m"
quotient of kinematic viscosity and magnetic viscosity in an electrically conducting liquid, expressed by ; where is…
11-8.11
Roberts numberRo
quotient of thermal diffusivity and magnetic viscosity in an electrically conducting liquid, expressed by ; where is…
11-8.12
Stuart numberStw
quotient of magnetic forces and inertia forces in an electrically conducting liquid, expressed by ; where is magnetic…
11-8.13
magnetic numberN_(mg)
quotient of magnetic forces and viscous forces in an electrically conducting fluid, expressed by ; where is magnetic…
11-8.14
electric field parameterEf
quotient of Coulomb force and Lorentz force on moving electrically charged material or particles, expressed by ; where…
11-8.15
Hall numberH_"c"
quotient of gyro frequency and collision frequency in a plasma, expressed by ; where is cyclotron angular frequency…
11-8.16
Lundquist numberLu
quotient of Alfvén speed and magneto-dynamic speed in a plasma, expressed by ; where is magnetic flux density…
ent
11-8.17
Joule magnetic numberJo_"m"
quotient of Joule heating energy and magnetic field energy in a plasma, expressed by ; where is mass density…
11-8.18
Grashof magnetic numberGr_"m"
mathematical expression for the heat transfer by free thermo-magnetic convection of a paramagnetic fluid under gravity,…
11-8.19
Naze numberNa
quotient of velocity of Alfvén waves and velocity of sound in a plasma, expressed by ; where is magnetic flux density…
ent
11-8.20
Reynolds electric numberRe_"e"
quotient of speed of a fluid and average drift speed of the charged particles in an electrically conducting fluid,…
11-8.21
Ampère numberAm
relation between electric surface current and magnetic field strength in an electrically conducting liquid, expressed…
11-9.1
Arrhenius numberalpha
quotient of chemical activation energy and thermal energy; in a chemical reaction it is the exponential factor of the…
11-9.2
Landau-Ginzburg numberkappa
quotient of penetration depth of a magnetic field into a superconductor and the coherence length of thermodynamic…
Part 12: Condensed Matter9 of 60 entries
12-4
Bragg anglevartheta
angle between the scattered ray and the lattice plane
ent
12-5.1
short-range order parameterr
fraction of nearest-neighbour atom pairs in an Ising ferromagnet having magnetic moments in one direction, minus the…
ent
12-5.2
long-range order parameterR
fraction of atoms in an Ising ferromagnet having magnetic moments in one direction, minus the fraction having magnetic…
ent
12-5.3
atomic scattering factorf
quotient of radiation amplitude scattered by the atom and radiation amplitude scattered by a single electron
ent
12-5.4
structure factorF(h,k,l)
quantity given by: where is the atomic scattering factor (t12-5.3) for atom , , , are fractional coordinates of its…
ent
12-8
Debye-Waller factorD
factor by which the intensity of a diffraction line is reduced because of the lattice vibrations
ent
12-13
thermodynamic Grüneisen parametergamma_"G"
quantity given by: where is cubic expansion coefficient (iso80000-5), is isothermal compressibility (iso80000-5), is…
12-14
Grüneisen parametergamma
quantity given by minus the partial differential quotient: where is a lattice vibration frequency (iso80000-3), and is…
ent
12-31
mobility ratiob
quotient of mobilities (iso80000-10) of electrons and holes, respectively
Part 13: Information Science66 of 84 entries
13-1
traffic intensityii(A)
number of simultaneously busy resources in a particular pool of resources
13-2
traffic offered intensityii(A)_o
traffic intensity (t13-1) of the traffic that would have been generated by the users of a pool of resources if their…
13-3
traffic carried intensity, traffic loadii(Y)
traffic intensity (t13-1) of the traffic served by a particular pool of resources
13-4
mean queue lengthii(L)
time average of queue length
13-5
loss probabilityii(B)
probability for losing a call attempt
13-6
waiting probabilityii(W)
probability for waiting for a resource
13-7
call intensity, calling ratelambda
number of call attempts over a specified time interval divided by the duration (iso80000-3) of this interval
↑ 1
13-8
completed call intensitymu
call intensity (t13-7) for the call attempts that result in the transmission of an answer signal
↑ 1
13-9
storage capacity, storage sizeii(M)
amount of data that can be contained in a storage device, expressed as a number of specified data elements
13-10
equivalent binary storage capacityii(M)_("e")
where is the number of possible states of the given device
13-11
transfer rater
quotient of the number of specified data elements transferred in a time interval by the duration of this interval
↑ 1
13-13
binary digit rate, bit rater_"b", r_"bit"
transfer rate (t13-11) where the data elements are binary digits
↑ 1
13-15
equivalent binary digit rate, equivalent bit rater_"e"
binary digit rate (t13-13) equivalent to a transfer rate (t13-11) for specified data elements
↑ 1
13-16
modulation rate, line digit rater_"m"
inverse of the shortest duration of a signal element
↑ 1
13-20
error probabilityii(P)
probability that a data element be incorrectly received
13-21
Hamming distanced_"n"
number of digit positions in which the corresponding digits of two words of the same length are different
13-23
decision contentii(D)_a
where is the number of possibilities at each decision and the number of events
13-24
information contentI(x)
where is the probability of event
13-25
entropyii(H)
for the set where is the probability and is the information content of event
13-26
maximum entropyii(H)_0
maximum entropy occurs when for
13-27
relative entropyii(H)_r
where is entropy (t13-25) and is maximum entropy (t13-26)
↑ 1
13-28
redundancyii(R)
where is entropy (t13-25) and is maximum entropy (t13-26)
13-29
relative redundancyr
where + is redundancy (t13-28) and + is maximum entropy (t13-26)
↑ 1
13-30
joint information contentii(I)(x, y)
where is the joint probability of events and
13-31
conditional information contentii(I)(x\|y)
information content (t13-2) of event under the condition that has occurred:
13-32
conditional entropy, mean conditional information content, average conditional information contentii(H)(ii(X)\|ii(Y))
where is the joint probability of events and , and is conditional information content (t13-31)
13-33
equivocationii(H)(ii(X)\|ii(Y))
conditional entropy (t13-32) of a set of emitted characters given the set of received characters
13-34
irrelevanceii(H)(ii(Y)\|ii(X))
conditional entropy (t13-32) of a set of received characters given the set of emitted characters: , where is…
13-35
transinformation contentii(T)(x,y)
where and are the information contents (t13-24) of events and , respectively, and is their joint information content…
13-36
mean transinformation contentii(T)
for the sets , , where is the joint probability of events and , and is their transinformation content (t13-35)
↑ 1
13-37
character mean entropyii(H)'
where is the entropy (t13-3) of the set of all sequences of characters
13-39
character mean transinformation contentii(T)'
where is the mean transinformation content (t13-36) for all pairs of input and output sequences of characters
13-41
channel capacity per character, channel capacityii(C)'
where is character mean transinformation content (t13-39)
13-1
traffic intensityA
number of simultaneously busy resources in a particular pool of resources
13-2
traffic offered intensityA_o
traffic intensity (t13-1) of the traffic that would have been generated by the users of a pool of resources if their…
13-3
traffic carried intensity, traffic loadY
traffic intensity (t13-1) of the traffic served by a particular pool of resources
13-4
mean queue lengthL
time average of queue length
13-5
loss probabilityB
probability for losing a call attempt
13-6
waiting probabilityW
probability for waiting for a resource
13-7
call intensity, calling ratelambda
number of call attempts over a specified time interval divided by the duration (ISO 80000-3:2019, item 3-9) of this…
↑ 1
13-8
completed call intensitymu
call intensity (t13-7) for the call attempts that result in the transmission of an answer signal
↑ 1
13-9
storage capacity, storage sizeM
amount of data that can be contained in a storage device, expressed as a number of specified data elements
13-10
equivalent binary storage capacityM_e
where is the number of possible states of the given device
13-11
transfer rater
quotient of the number of specified data elements transferred in a time interval by the duration of this interval
↑ 1
13-13
binary digit rate, bit rater_{"bit"}
transfer rate (t13-11) where the data elements are binary digits
↑ 1
13-15
equivalent binary digit rate, equivalent bit rater_e
binary digit rate (t13-13) equivalent to a transfer rate (t13-11) for specified data elements
↑ 1
13-16
modulation rate, line digit rater_m
inverse of the shortest duration of a signal element
↑ 1
13-20
error probabilityP
probability that a data element be incorrectly received
13-21
Hamming distanced_h
number of digit positions in which the corresponding digits of two words of the same length are different
13-23
decision contentD_a
where is the number of possibilities at each decision and the number of events
13-24
information contentI(x)
+ + + where is the probability of event
13-25
entropyH
for the set where is the probability, and is the information content of event
13-26
maximum entropyH_0
maximum entropy occurs when for
13-27
relative entropyH_r
where is entropy (t13-25) and is maximum entropy (t13-26)
↑ 1
13-28
redundancyR
where H is entropy (t13-25) and is maximum entropy (t13-26)
13-29
relative redundancyr
where is redundancy (t13-28) and is maximum entropy (t13-26)
↑ 1
13-30
joint information contentI(x,y)
is the joint probability of events and
13-31
conditional information contentI(x\|y)
information content (t13-2) of event under the condition that has occurred:
13-32
conditional entropy, mean conditional information content, average conditional information contentH(x\|y)
where is the joint probability of events and , and is conditional information content (t13-31)
13-33
equivocationH_{"+"}(X\|I)
conditional entropy (t13-32) of a set of emitted characters given the set I of received characters
13-34
irrelevanceH_{"-"}(I\|X)
conditional entropy (t13-32) of a set of received characters given the set of emitted characters: , where is…
13-35
transinformation content, mutual informationT(x,y)
where and are the information contents (t13-24) of events and , respectively, and is their joint information content…
13-36
mean transinformation contentT
for the sets , , where is the joint probability of events and , and is their transinformation content (t13-35)
↑ 1
13-37
character mean entropyH'
where is the entropy (t13-25) of the set of all sequences of characters
13-39
character mean transinformation contentT'
where is the mean transinformation content (t13-36) for all pairs of input and output sequences of characters
13-41
channel capacity per characterC'
where is character mean transinformation content (t13-39)