<unk>  is a measure comparing the vapor pressures of the components in a liquid mixture of chemicals. This quantity is widely used in designing large industrial distillation processes. In effect, it indicates the ease or difficulty of using distillation to separate the more volatile components from the less volatile components in a mixture.  By convention,<unk>  is usually denoted as 
α
{\displaystyle \alpha }
.<unk> es are used in the design of all types of distillation processes as well as other separation or absorption processes that involve the contacting of vapor and liquid phases in a series of equilibrium stages.<unk> es are not used in separation or absorption processes that involve components reacting with each other (for example, the absorption of gaseous carbon dioxide in aqueous solutions of sodium hydroxide).
Relative volatility
Dominance relationship
Incidence 
Affective spectrum
Mean lifetime
Sensitivity 
Multistable perception
Specificity 