▁of ▁Esp í rito ▁Santo ▁in ▁eastern ▁Brazil . ▁ ▁References ▁ ▁rub rol il ac ina ▁Category : Pl ants ▁described ▁in ▁ 1 9 9 3 ▁Category : Fl ora ▁of ▁Brazil <0x0A> </s> ▁A ▁val ve ▁exer cis er ▁is ▁a ▁device ▁to ▁turn ▁a ▁val ve ▁on ▁and ▁off ▁repeatedly ▁to ▁try ▁to ▁stop ▁the ▁val ve ▁from ▁becoming ▁so ▁st iff ▁that ▁it ▁cannot ▁be ▁turned ▁on ▁or ▁off . ▁ ▁References ▁ ▁Category : P ip ing ▁* ▁Category : Pl umb ing <0x0A> </s> ▁In ▁a ▁tor oid al ▁fusion ▁power ▁re actor , ▁the ▁magnetic ▁fields ▁conf ining ▁the ▁pl asma ▁are ▁formed ▁in ▁a ▁hel ical ▁shape , ▁w inding ▁around ▁the ▁interior ▁of ▁the ▁re actor . ▁The ▁safety ▁factor , ▁l abeled ▁q ▁or ▁q ( r ), ▁is ▁the ▁ratio ▁of ▁the ▁times ▁a ▁particular ▁magnetic ▁field ▁line ▁travel s ▁around ▁a ▁tor oid al ▁conf in ement ▁area ' s ▁" long ▁way " ▁( tor oid ally ) ▁to ▁the ▁" short ▁way " ▁( pol oid ally ). ▁ ▁The ▁term ▁" s af ety " ▁refers ▁to ▁the ▁resulting ▁stability ▁of ▁the ▁pl asma ; ▁pl as mas ▁that ▁rotate ▁around ▁the ▁tor us ▁pol oid ally ▁about ▁the ▁same ▁number ▁of ▁times ▁as ▁tor oid ally ▁are ▁inher ently ▁less ▁sus cept ible ▁to ▁certain ▁inst abilities . ▁The ▁term ▁is ▁most ▁commonly ▁used ▁when ▁referring ▁to ▁to k am ak ▁devices . ▁Although ▁the ▁same