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^112= _ EJEJ ^l]E 129 ^I+q= 'IZql E+4 E+"JE 4uz1 H6Iq "J4 +er+ zlA)4 +4E ++^J ql rtl+ "J olg +^l + + BttrI. E+"J g E+6IB 4€-r+ zJ4 e =g ulzJ (hard packing) : =4^q gE, +ol @ +rJ ulzJ (semi-hard packing) : tr] BBa , aP a ^lE @ €+ tllzJ (soft packing) : +^I(a) ^l+61= tlrJql q4 l.+Eg "J+ ZE"l HalErl , E1(cut of cylinder)ol E + 7)rtlg ull= vlrJg dq *"1 slol E"8a zlnlel dts"l 6,ea171 gtrI. g6J vllzJ|- = "J+(nip)*gE allo}"J ql4tlg gg + 91trI. ql4"Jol zls$ "Jz E*"1 tg-'|zl *6lq *4Eg = .41 5lE E€ol =.4, "Jdg ?9zl Hzl 71 Bvl. =g rlrJe "Jdel "Jr E+E +s+ +eE "J+.Js_trE E€6lq dzlzl i +q, ']]44s Eqtlq. 44+ !-S6I= 4"1 "J+€ E4ag ^I+6I= *B.l tr}.'J+€ grdag ^I+g ull= "J+ E€e d+ql^l 'Jq+q,.zF9 EBE 4 tr}. HEe E?8ag ^I+g "ll= A+ql= E€9zl 9*z -z*6ol EBq=ql , ol ,)+ pzl (bulge, "J*) €*"1 4l aJ4 t:z? 4-16le Bqa s.trel EBol4. +E E= "J5 "J+€ / za=s Bxl €t+ (a) "J+€el EB a-a 4'1 6 EaJT! E'Jel HJ:d cf. +gE rd+ "J4g "I Elsld+ql oJazl lzl 9+E+ "J7= E6l7l ql s^l +E"l += +gEg "J6J4. E te-+.E "JE zI q.Jg 6}zl trJ qel 7l^l olzl (etch).+g i+ q"J 4zl r*4. +"JEE Ege q+4 ,Jq. e Hl+d+ql "Jr ++9 *zl +r+. @ ulElC+= zl*ol +tr1. @ Eld+= dE61al 6Jtr1. @ Eld+9 84. *zlt4 @ +EE gE= gC6}2l ++. r*E \ ot*a \ s,E l+ (b) !-E€E Ee ri E6l +o o / *ars