Mα	Partial mass of constituent α within the mixture (usually defined locally)	kg
Vα	Partial volume of constituent α within the mixture (usually defined locally)	m3
Πα	Mass production rate of constituent α (usually defined locally)	kg · s−1
ρα	Apparent spatial mass density of constituent α: current mass of constituent α per unit current volume of mixture	kg · m−3
${\rho }_R^{\alpha }$	Apparent referential mass density of constituent α: current mass of constituent α per unit reference volume of mixture	kg · m−3
${\mathrm{\Phi }}_R^{\alpha }$	Referential volume fraction of constituent α: current volume of constituent α per unit reference volume of mixture	[−]
Φα	Spatial volume fraction of constituent α: current volume of constituent α per unit current volume of mixture	[−]
ϕα	Spatial mass fraction of constituent α: current mass of constituent α per unit current mass of mixture	[−]
mα	Spatial mass density production rate of constituent α: current mass production rate of constituent α per unit current volume of mixture	kg · s−1 · m−3
$m_R^{\alpha }$	Referential mass density production rate of constituent α: current mass production rate of constituent α per unit reference volume of mixture	kg · s−1 · m−3
$m_N^{\alpha }$	Referential nominal mass density production rate of constituent α: current nominal mass production rate of constituent α per unit reference volume of mixture	kg · s−1 · m−3
$W_R^{\alpha }$	Referential strain energy function of constituent α: current strain energy of mass of constituent α within the mixture per unit reference volume of mixture	J · m−3