▁at ▁the ▁extremely ▁low ▁temper atures ▁needed ▁for ▁some ▁special ized ▁scientific ▁research ▁applications . ▁ ▁Some ▁fluid ▁bear ings ▁ ▁Fo il ▁bear ings ▁ ▁Fo il ▁bear ings ▁are ▁a ▁type ▁of ▁fluid ▁dynamic ▁air ▁bearing ▁that ▁were ▁introduced ▁in ▁high ▁speed ▁tur bine ▁applications ▁in ▁the ▁ 1 9 6 0 s ▁by ▁Gar rett ▁A i Res earch . ▁ ▁They ▁use ▁a ▁gas ▁as ▁the ▁working ▁fluid , ▁usually ▁air , ▁and ▁require ▁no ▁external ▁press ur isation ▁system ▁but ▁need ▁careful ▁design ▁to ▁prevent ▁wear ▁during ▁spin - up ▁and ▁spin - down ▁when ▁the ▁bearing ▁makes ▁physical ▁contact . ▁ ▁Journal ▁bear ings ▁ ▁Journal ▁bear ings ▁are ▁lub ric ated ▁with ▁fluid . ▁The ▁working ▁part ▁of ▁the ▁bearing ▁oper ates ▁by ▁carrying ▁oil ▁at ▁a ▁low ▁pressure ▁and ▁is ▁com pressed ▁to ▁allow ▁the ▁bearing ▁to ▁spin ▁around ▁the ▁sh aft ▁without ▁any ▁contact . ▁ ▁Water - lub ric ated ▁rub ber ▁bear ings ▁ ▁Water - lub ric ated ▁rub ber ▁bear ings ▁have ▁long ▁cyl ind rical ▁metal ▁shell ▁that ▁hosts ▁multiple ▁rub ber ▁st aves ▁separated ▁by ▁ax ial ▁gro ov es . ▁The ▁usage ▁of ▁the ▁bearing ▁has ▁three ▁major ▁advantages : ▁( i ) ▁p ump ed ▁water ▁going ▁through ▁the ▁bearing ▁is ▁convenient ly ▁used ▁as ▁a ▁lub ric ant , ▁which ▁reduces ▁p ump ▁operation ▁cost ; ▁( ii ) ▁water ▁flow ▁takes ▁away ▁heat ▁and ▁fine ▁particles ▁through ▁the ▁bearing ▁gro ov es ; ▁and