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Design of Air Duct in Hospital

Jun 02, 2018

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    DESIGN OF AIR DUCT

    DESIGN CONDITIONS:

    Inside room conditions

    Temperature ------------------------------------------------------DBCo22

    ------------------------------------------------------

    WBCo16

    Outside room conditions

    Temperature ------------------------------------------------------

    DBCo

    34

    ------------------------------------------------------

    WBCo27

    Temperature of supply air ----------------------------------------------CO15

    Mass of outside air,mo ----------------------------------------- Smof%10

    Mass of recirculated air, mR ----------------------------------------- Smof%90

    21

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    Air Properties

    From ASHRAE PSYCHROMETRIC CHART M!E!T!C p"#e $%

    Outside room conditions WBCDBC oO 2732!

    kg

    kJh

    kg

    m

    kg

    kgW OO

    da

    v

    O 6"#5$#9#"0$0199"03

    ===

    Inside room conditions WBCDBC oO 1622!

    kg

    kJh

    kg

    m

    kg

    kgW OO

    da

    v

    O 45$#4#"0$00#9"03

    ===

    M"ss o& supp'( "ir mS

    % &% &

    srpa

    s

    SsrpaSs ttc

    QmttcmQ

    -'$-'

    ()ere*

    Sm ' mass of supply air

    pac ' specific )eat of air, KkgkJ +0062"1

    rt ' iside room temperature, C22

    st ' supply air temperature, C+15

    T)erefore,

    ( ) sec66"32

    15-220062"1

    037"230 kg

    KKkg

    kJ

    kW

    mO

    O

    S =

    =

    M"ss o& outside "ir mO

    RoS mmmmm $'' 41

    22

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    ()ere*

    Sm ' mass of supply air, skg66"32

    Rm ' mass of recirculated air, Smof%90

    T)erefore,

    ( ) ( ) sec266"39"01sec66"329"01 kgkgmm SO ===

    )o'ume &'o* r"te o& outside "ir )o

    OOO mV '

    ()ere*

    Om ' mass of outside air, skg266"3

    O ' specific .olume of outside air, kgm3

    #9#"0

    T)erefore,

    sec93"2#9#"0

    sec266"3

    33 m

    kg

    mkgVO =

    =

    M"ss o& recircu'"ted "ir m

    R

    OSRRoS mmmmmm $ =+=

    ()ere*

    Sm ' mass of supply air, skg66"32

    Om ' mass of outside air, sec266"3 kg

    T)erefore,

    sec39"29sec266"3sec66"32 kgkgkgmR ==

    )o'ume &'o* r"te o& recircu'"ted "ir )R

    iRR mV '

    23

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    ()ere*

    Rm ' mass of recirculated air, skg39"29

    i ' specific .olume of iside air, kgm3#4#"0

    T)erefore,

    sec93"24#4#"0

    sec39"29

    33m

    kg

    mkgVR =

    =

    Temper"ture o& "ir enterin# t+e AHU t,

    From t+e &i#ure considerin# point ,

    /y temperature alace,

    S

    ROoSROo

    m

    tmtmttmtmtm 4224 $

    +==+

    ()ere*

    Om ' mass of outside air, sec266"3 kg

    Ot ' temperature of outside air, CO

    34

    Rm ' mass of recirculated air, skg93"29

    4t ' iside air temperature, Co22

    Sm ' mass of supply air, skg66"32

    T)erefore,

    ( )( ) ( )( ) Ckg

    CkgCkgt

    OOO

    56"23sec66"32

    22sec93"2934sec266"32 =+=

    C"p"cit( o& AHU -AHU

    14 -' hhmQ SCDA

    ()ere*

    24

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    Sm ' mass of supply air, skg66"32

    4h ' et)alpy of air eteri t)e , kgkJ

    1h ' et)alpy of air lea.i t)e , kgkJ

    Ent+"'p( o& "ir enterin# t+e AHU 2h

    From t+e &i#ure considerin# point ,

    /y )eat alace,

    S

    ROo

    SROo m

    hmhm

    hhmhmhm

    4

    224 $

    +==+

    ()ere*

    Om ' mass of outside air, sec266"3 kg

    Oh ' et)alpy of outside air, kgkJ6"#5

    Rm ' mass of recirculated air, skg93"29

    4h ' et)alpy of recirculated air, kgkJ45

    Sm ' mass of supply air, skg66"32

    T)erefore,

    ( ) ( ) ( ) ( )kg

    kJ

    kg

    kgkJkgkgkJkgh #"49

    sec66"32

    45sec93"296"#5sec266"34 =

    +=

    Ent+"'p( o& "ir 'e".in# t+e AHU 3h

    ( )S

    TST

    m

    QhhhhmQ -$- 4334 ==

    ()ere*

    25

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    TQ ' total )eat load, TkW22#"476

    Sm ' mass of supply air, skg66"32

    4h ' et)alpy of iside air, kgkJ45

    T)erefore,

    kg

    kJ

    kg

    kW

    kg

    kJh T 42"30

    sec66"32

    22#"476-45

    3 ==

    T)us,

    ( ) TORorkWkg

    kJkgQAHU 9#"1799"63242"30-#"49

    sec66"32 =

    =

    )o'ume o& supp'( "ir )S

    1' mV SS

    ()ere*

    Sm ' mass of supply air, skg66"32

    1 ' specific .olume of supply air, kgm3

    From ASHRAE PSYCHROMETRIC CHART M!E!T!C p"#e $%

    kgkJhDBCO 42"3015! 1 =

    kg

    m3

    1 #24"0=

    T)erefore,

    ( )( ) sec9"26#24"0sec66"323

    3 m

    kgmkgVS ==

    26

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    AIR DUCT SI/ING

    DESIGN CONDITIONS:

    olume flo rate of supply air ----------------------------------- sec9"26 3m

    uct dimesios ------------------------------------------------------( ' 4

    8o" of uits ------------------------------------------------------2

    8o" of rac) tae-off ---------------------------------------------5

    8o" of outlet per rac) tae off ------------------------------------

    4

    Met)od of calculatio ------------------------------------------------------

    :itti data

    ;lo, ier outer radii ratio -------------------------- 2"0

    le, turs ad rac)es ----------------------------------- O90

    27

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    )o'ume &'o* r"te o& supp'( "ir per 0r"nc+ t"1e2o&& -3

    sec3#"55

    sec9"26 33 mm

    offTakBra!cho"#m$r

    V

    Q

    S

    B ===

    )o'ume &'o* r"te o& supp'( "ir per out'et -O

    sec345"1

    4

    sec3#"5- 33

    mm

    O#t%tsof"#m$r

    offTakBra!chprAirS#pp%&ofRat'%o(Vo%#mQO ===

    Duct Si4es

    For t+e m"in duct &rom t+e &"n out'et to point O

    :rom &i#ure 52, Pressure drop in str"i#+t circu'"r s+eet met"' ducts

    R;:R

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    ( )( ) 25"0

    625"0

    " 30"1$a

    a$D f*

    +=

    ()ere*

    a ' H' )ei)t of t)e rectaular duct, m

    ' W' idt) of t)e rectaular duct, m

    @ustituti, HW 4= to t)e eBuatio ao.e

    ( )( ) ( )( ) ( )( ) HHHHHWHHWD f* 0677"25430"15430"130"1 25"025"025"1625"0

    25"0

    625"02

    25"0

    625"0

    " ===+

    =

    T)us,

    *#atio!(orki!gDHf* =

    "4#36"0

    For t+e +ei#+t 'OH

    ( ) mmH'O 694"0436"14#36"0 ==

    For t+e *idt+ 'OW

    ( ) mmW'O 7#"2694"04 ==

    For t+e si4e o& duct, 'OA

    22 193093"17#"2694"0 mmmm+mW+HA 'O'O'O ====

    Run O to A t*o 0r"nc+ t"1e 8 o&& supp'ied

    29

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    :rom &i#ure 52, Pressure drop in str"i#+t circu'"r s+eet met"' ducts

    R;:R

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    ( ) mmHOB 6316"0306"14#36"0 ==

    ( ) mmWOB 52"2324"04 ==

    259"152"26316"0 mm+mW+HA OBOBOB ===

    Run 3 to C 9 3r"nc+ t"1e 8 o&& supp'ied

    :rom &i#ure 52, Pressure drop in str"i#+t circu'"r s+eet met"' ducts

    R;:R

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    Run C to D 0r"nc+ t"1e 8 o&& supp'ied

    :rom &i#ure 52, Pressure drop in str"i#+t circu'"r s+eet met"' ducts

    R;:R

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    mD f* 756"0" =

    T)erefore,

    ( ) mmHCD 3656"0756"04#36"0 ==

    ( ) mmWCD 46"13656"04 ==

    2533#"046"13656"0 mm+mW+HA CDCDCD ===

    3r"nc+ out'et dimensions

    Note:

    @ice t)e umer of outlets i eac) rac) tae C off are eBual for t)e )ole

    system, oly oe rac) tae C off ill e cosidered i computi for t)e duct

    dimesios ad t)e .alues otaied ill e replicated i all se.e %7& rac) outlets"

    Considerin# 3r"nc+ T"1e 8 o&& A

    Run A 8 ; out'ets supp'ied

    :rom &i#ure 52, Pressure drop in str"i#+t circu'"r s+eet met"' ducts

    R;:R

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    ( ) mmHA 3656"0756"04#36"01 ==

    ( ) mmWA

    4624"13656"041

    ==

    2

    111 5347"04624"13656"0 mm+mW+HA AAA ===

    Run ; 8 , 9 out'ets supp'ied

    :rom &i#ure 52, Pressure drop in str"i#+t circu'"r s+eet met"' ducts

    R;:R

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    sec937"1393"1

    sec9"262

    3

    0

    0 mm

    m

    A

    Q

    '

    ''A ===

    ()ere*

    'OQ ' 26"9 sm3

    'OA ' 1"932

    m

    Run A23 AB

    sec53"1359"1

    sec52"212

    3

    mm

    m

    A

    Q

    AB

    AB

    AB ===

    ()ere*

    ABQ ' 21"52 sm3

    ABA ' 1"592

    m

    Run 3 2C BC

    sec26"12

    316"1

    sec14"162

    3

    m

    m

    m

    A

    Q

    BC

    BC

    BC ===

    ()ere*

    BCQ ' 16"14 sm3

    BCA ' 1"3162

    m

    Run C 2 D CD

    sec325"12#73"0

    sec76"102

    3

    mm

    m

    A

    Q

    CD

    CD

    CD ===

    ()ere*

    CDQ ' 10"76 sm3

    36

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    CDA ' 0"#732

    m

    Run D 2 E D,

    sec07#"10533#"0

    sec3#"52

    3

    mm

    m

    A

    Q

    D,

    D,D, ===

    ()ere*

    D,Q ' 5"3# sm3

    D,A ' 0"533#2m

    3r"nc+ Out'ets

    Note:

    @ice t)e umer of outlets i eac) rac) tae C off are eBual for t)e )ole

    system, oly oe rac) tae C off ill e cosidered i computi for t)e duct .elocities

    ad t)e .alues otaied ill e replicated i all se.e %7& rac) outlets"

    Run A 2 ; 1A

    sec06"105347"0

    sec3#"52

    3

    1

    1

    1 mm

    m

    A

    Q

    A

    A

    A ===

    ()ere*

    1AQ ' 5"3# sm3

    1AA ' 0"53472

    m

    Run ; 2 , 12

    sec#02"#45#4"0

    sec035"42

    3

    12

    12

    12 m

    m

    m

    A

    Q===

    37

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    ()ere*

    12Q ' 4"035 sm3

    12A ' 0"45#42

    m

    Run , 2 9 23

    sec57"#314"0

    sec69"22

    3

    23

    23

    23 mm

    m

    A

    Q===

    ()ere*

    23Q ' 2"69 sm3

    23A ' 0"3142

    m

    Run 9 2 34

    sec77"7173"0

    sec345"12

    3

    34

    34

    34 mm

    m

    A

    Q===

    ()ere*

    34Q ' 1"345 sm3

    34A ' 0"173 2m

    Determin"tion o& Pressure Drops

    3#

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    Considerin# t+e Run4321 AAAA'OA

    Run FO Str"i#+t Duct

    ( ) ( ) )am)amm)-) 'O'O 95#"65"163#7"4 ===

    Run O Turn

    :rom &i#ure 5 8 7 Pressure 'osses in rect"n#u'"r e'0o*sR;:R

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    ,= 1#"17# 1"2041

    @ice t)e temperature of t)e supply air is at 15

    0

    ?, y iterpolatio,

    ! 15 ?' 1"2254 D m3

    T)erefore,

    ( ) ( ) ( ) ( ) ( ) )amkgmv) airOBOT 75"292

    2254"1sec937"1325"0

    225"0

    322

    ===

    Run OA Str"i#+t Duct

    ( ) ( ) )am)amm)-) OAOA 654"155"14360"10 ===

    3r"nc+ t"1e 8 o&& A Turn

    :rom &i#ure 5 8 7 Pressure 'osses in rect"n#u'"r e'0o*sR;:R, 13"937 m D sec

    T)erefore,

    ( ) ( )

    ( ) ( ) ( )

    )a

    mkgmv

    )

    airOB

    AT 75"292

    2254"1sec937"13

    25"0225"0

    322

    ===

    Run AA; Str"i#+t Duct

    ( ) ( ) )am)amm)-)AAAA

    255"35"11703"211 ===

    40

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    Run AA

    ,

    Str"i#+t Duct

    ( ) ( ) )am)amm)-)AAAA

    6623"#5"17749"522 ===

    Run AA9 Str"i#+t Duct

    ( ) ( ) )am)amm)-)AAAA

    4195"145"1613"933 ===

    Run AA Str"i#+t Duct

    ( ) ( ) )am)amm)-)AAAA

    6951"1#5"14634"1244 ===

    T)erefore,

    ( )

    )a)

    )a

    )))))))))

    'OBA

    AAAAAAAAATOAOT'O'OA

    1439"127

    6951"1#4195"146623"#225"375"29654"1575"2995#"6

    7

    4 4321

    =+++++++=

    +++++++=

    Considerin# t+e Run 4321 BBB'OBB

    41

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    Run FO Str"i#+t Duct

    ( ) ( ) )am)amm)-) 'O'O 95#"65"163#7"4 ===

    Run O Turn

    :rom &i#ure 5 8 7 Pressure 'osses in rect"n#u'"r e'0o*sR;:R/, 13"937 m D sec

    T)erefore,

    ( ) ( ) ( ) ( ) ( ) )amkgmv) airTOTO 75"292

    2254"1sec937"1325"0

    225"0

    322

    ===

    3r"nc+ t"1e 8 o&& A Duct Str"i#+t T+rou#+

    :rom E6u"tion 5 8 ;5R;:R

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    ( )( )

    ( ) ( )( )

    )a)

    m)

    V

    VV)

    ADST

    ADST

    AB

    OAairOAADST

    03#"0

    937"13

    53"1314"0

    2

    2254"1sec53"13

    14"02

    22

    22

    =

    =

    =

    Run O3 Turn

    :rom &i#ure 5 8 7 Pressure 'osses in rect"n#u'"r e'0o*sR;:R/, 13"53 m D sec

    T)erefore,

    ( ) ( ) ( ) ( ) ( ) )amkgmv) airTOBTOB 04"2#2

    2254"1sec53"1325"0

    225"0

    322

    ===

    Run O3 Str"i#+t Duct

    ( ) ( ) )am)amm)-) OBOB 204"275"1136"1# ===

    43

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    Run 33; Str"i#+t Duct

    ( ) ( ) )am)amm)-)BBBB

    5442"35"1362#"211 ===

    Run 33, Str"i#+t Duct

    ( ) ( ) )am)amm)-)BBBB

    9511"#5"19674"522 ===

    Run 339 Str"i#+t Duct

    ( ) ( ) )am)amm)-) BBBB 70#"145"1#055"933 ===

    Run 33 Str"i#+t Duct

    ( ) ( ) )am)amm)-)BBBB

    9#3#"1#5"16559"1244 ===

    T)erefore,

    (

    )a)

    ))))))))))

    'OBA

    BBBBBBOBTOBDSTATO'OBBB'OBB

    1771"13#

    170#"149511"#5442"3204"2704"2#03#"075"2995#"6

    7

    3214321

    =++++++++=

    ++++++++=

    Considerin# t+e Run 4321 CCC'OCC

    44

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    Run FO Str"i#+t Duct

    ( ) ( ) )am)amm)-) 'O'O 95#"65"163#7"4 ===

    Run O Turn

    :rom &i#ure 5 8 7 Pressure 'osses in rect"n#u'"r e'0o*sR;:R/, 13"937 m D sec

    T)erefore,

    ( ) ( ) ( ) ( ) ( ) )amkgmv) airTOTO 75"292

    2254"1sec937"1325"0

    225"0

    322

    ===

    3r"nc+ t"1e 8 o&& A Duct Str"i#+t T+rou#+

    45

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    :rom E6u"tion 5 8 ;5R;:R

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    T)erefore,

    ( ) ( ) ( ) ( ) ( ) )amkgmv) airTOCTOC 0234"232

    2254"1sec26"1225"0

    225"0

    322

    ===

    Run OC Str"i#+t Duct

    ( ) ( ) )am)amm)-) OCOC 754"3#5"1#36"25 ===

    Run CC; Str"i#+t Duct

    ( ) ( ) )am)amm)-)CCCC

    623"35"14153"211 ===

    Run CC, Str"i#+t Duct

    ( ) ( ) )am)amm)-)CCCC

    029#5"95"10199"622 ===

    Run CC9 Str"i#+t Duct

    ( ) ( ) )am)amm)-)CCCC

    7#7"145"1#5#"933 ===

    Run CC Str"i#+t Duct

    ( ) ( ) )am)amm)-)CCCC

    0626"195"170#4"1244 ===

    T)erefore,

    47

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    )a)

    )a

    )))))))))

    CCC'OCC

    CCCCOCTOCDSTBDSTATO'OCCC'OCC

    05#3"145

    0626"197#7"14029#5"9

    623"3754"3#0234"2303245"003#"075"2995#"6

    4321

    214321

    =

    +++

    ++++++=

    ++++++++=

    Considerin# t+e Run 4321 DDD'ODD

    Run FO Str"i#+t Duct

    ( ) ( ) )am)amm)-) 'O'O 95#"65"163#7"4 ===

    Run O Turn

    4#

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    :rom &i#ure 5 8 7 Pressure 'osses in rect"n#u'"r e'0o*sR;:R/, 13"937 m D sec

    T)erefore,

    ( ) ( ) ( ) ( ) ( ) )amkgmv) airTOTO 75"292

    2254"1sec937"1325"0

    225"0

    322

    ===

    3r"nc+ t"1e 8 o&& A Duct Str"i#+t T+rou#+

    :rom E6u"tion 5 8 ;5R;:R

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    ( )( )

    ( ) ( )( )

    )a)

    m)

    V

    VV)

    BDST

    BDST

    BC

    OBairBCBDST

    03245"0

    53"13

    26"1214"0

    2

    2254"1sec26"12

    14"02

    22

    22

    =

    =

    =

    3r"nc+ t"1e 8 o&& C Duct Str"i#+t T+rou#+

    :rom E6u"tion 5 8 ;5R;:R, 12"325 m D sec

    50

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    T)erefore,

    ( ) ( ) ( ) ( ) ( ) )amkgmv) airTODTOD 26#"232

    2254"1sec325"1225"0

    225"0

    322

    ===

    Run OD Str"i#+t Duct

    ( ) ( ) )am)amm)-) ODOD 304"505"1536"33 ===

    Run DD; Str"i#+t Duct

    ( ) ( ) )am)amm)-)DDDD

    9#96"25"19931"111 ===

    Run DD, Str"i#+t Duct

    ( ) ( ) )am)amm)-)DDDD

    #56"#5"1904"522 ===

    Run DD9 Str"i#+t Duct

    ( ) ( ) )am)amm)-)DDDD

    9579"125"163#6"#33 ===

    Run DD Str"i#+t Duct

    ( ) ( ) )am)amm)-)DDDD

    7746"165"11#31"1144 ===

    T)erefore,

    51

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    )a)

    )a

    )))))))))

    DDD'ODD

    DDODTODDSTDDSTBDSTATO'ODDD'ODD

    932"151

    7746"169579"12#56"#9#96"2

    304"5026#"23001046"003245"003#"075"2995#"6

    4321

    14321

    =

    ++++

    ++++++=

    +++++++=

    Considerin# t+e Run 4321 ,,,'O,,

    Run FO Str"i#+t Duct

    52

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    ( ) ( ) )am)amm)-) 'O'O 95#"65"163#7"4 ===

    Run O Turn

    :rom &i#ure 5 8 7 Pressure 'osses in rect"n#u'"r e'0o*sR;:R/, 13"937 m D sec

    T)erefore,

    ( ) ( ) ( ) ( ) ( ) )amkgmv) airTOTO 75"292

    2254"1sec937"1325"0

    225"0

    322

    ===

    3r"nc+ t"1e 8 o&& A Duct Str"i#+t T+rou#+

    :rom E6u"tion 5 8 ;5R;:R

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    3r"nc+ t"1e 8 o&& 3 Duct Str"i#+t T+rou#+

    :rom E6u"tion 5 8 ;5R;:R

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    Run EE, Str"i#+t Duct

    ( ) ( ) )am)amm)-),,,,

    316"#5"15437"522 ===

    Run EE9 Str"i#+t Duct

    ( ) ( ) )am)amm)-),,,,

    6939"125"14626"#33 ===

    Run EE Str"i#+t Duct

    ( ) ( ) )am)amm)-),,,,

    #"165"120005"1144 ===

    T)erefore,

    )a)

    )))))))))

    ,,,'O,,

    O,TO,DSTDDSTCDSTBDSTATO'O,,,'O,,

    122"156

    #"166939"12316"#295"3

    #54"61557"15#27"0001046"003245"003#"075"2995#"6

    4321

    4321

    =

    ++++

    +++++++=

    +++++++=