▁used ▁to ▁describe ▁the ▁efficiency ▁of ▁a ▁bed ▁of ▁per me able ▁( large - p ore ) ▁particles . ▁ ▁The ▁equation ▁is : ▁ ▁where ▁▁ ▁and ▁ ▁is ▁the ▁int ra part icular ▁P éc let ▁number . ▁ ▁See ▁also ▁Resol ution ▁( chrom at ography ) ▁ ▁Jan ▁van ▁De em ter ▁ ▁References ▁ ▁Category : Ch rom at ography ▁Category : Equ ations <0x0A> </s> ▁Europe ▁is ▁tradition ally ▁defined ▁as ▁one ▁of ▁seven ▁contin ents . ▁Phys i ograph ically , ▁it ▁is ▁the ▁north western ▁pen ins ula ▁of ▁the ▁larger ▁land mass ▁known ▁as ▁E uras ia ▁( or ▁the ▁larger ▁Af ro - E uras ia ); ▁Asia ▁occup ies ▁the ▁eastern ▁bulk ▁of ▁this ▁continuous ▁land mass ▁and ▁all ▁share ▁a ▁common ▁contin ental ▁sh elf . ▁Europe ' s ▁eastern ▁front ier ▁is ▁del ine ated ▁by ▁the ▁U ral ▁Mountains ▁in ▁Russia . ▁The ▁sout heast ▁boundary ▁with ▁Asia ▁is ▁not ▁univers ally ▁defined , ▁but ▁the ▁modern ▁definition ▁is ▁generally ▁the ▁U ral ▁River ▁or , ▁less ▁commonly , ▁the ▁Em ba ▁River . ▁The ▁boundary ▁continues ▁to ▁the ▁C asp ian ▁Sea , ▁the ▁cr est ▁of ▁the ▁C au cas us ▁Mountains ▁( or , ▁less ▁commonly , ▁the ▁river ▁K ura ▁in ▁the ▁C au cas us ), ▁and ▁on ▁to ▁the ▁Black ▁Sea . ▁The ▁Bos por us , ▁the ▁Sea ▁of ▁Mar m ara , ▁and ▁the ▁D ard an elles ▁conclude ▁the