Attenuation Coefficients Dependents Chemical Composition of Wood ... One of the most conventional radiation shielding materials are lead and mercury.
Available online at www.sciencedirect.com
ScienceDirect Procedia Engineering 127 (2015) 665 – 669
,QWHUQDWLRQDO&RQIHUHQFHRQ&RPSXWDWLRQDO+HDWDQG0DVV7UDQVIHU
$6WXG\RQ3KRWRQ,QWHUDFWLRQ&URVV6HFWLRQVDQG0DVV $WWHQXDWLRQ&RHIILFLHQWV'HSHQGHQWV&KHPLFDO&RPSRVLWLRQ RI:RRG0DWHULDOVDWWKH(QHUJ\5DQJHRI.HYWR0HY 6DULWKD%RGGXSHOOLD 1DJHVKZDUDUDR$6E D
'HSDUWPHQWRI3K\VLF.DNDWL\D8QLYHUVLW\:DUDQJDO7HODQJDQD,QGLD 'HSDUWPHQWRI3K\VLF.DNDWL\D8QLYHUVLW\:DUDQJDO7HODQJDQD,QGLD
E
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© 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license 7KH$XWKRUV3XEOLVKHGE\(OVHYLHU%9 (http://creativecommons.org/licenses/by-nc-nd/4.0/). 3HHUUHYLHZXQGHUUHVSRQVLELOLW\RIWKHRUJDQL]LQJFRPPLWWHHRI,&&+07± Peer-review under responsibility of the organizing committee of ICCHMT – 2015
.H\ZRUGV:RRGPDWHULDOV&KHPLFDO&RPSRVLWLRQ3DUWLDODWWHQXDWLRQFRHIILFLHQWV7RWDODWWHQXDWLRQFRHIILFLHQW;FRP
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
&RUUHVSRQGLQJDXWKRU7HO (PDLODGGUHVVVDULWKDERGGXSHOOL#JPDLOFRP
1877-7058 © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of ICCHMT – 2015
doi:10.1016/j.proeng.2015.11.362
666
Saritha Boddupelli and Nageshwara rao A.S. / Procedia Engineering 127 (2015) 665 – 669
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
YDULDWLRQRI&RPSZLWKHQHUJ\IRUGLIIHUHQWZRRGDQG3EFRPSRXQGVDQGLQGLFDWHVWKDWWKHUHLVQHJOLJLEOH YDULDWLRQRI&RPSDWDOOHQHUJLHV,QWKHPHGLXPHQHUJ\UHJLRQWKH&RPSWRQLQWHUDFWLRQSURFHVVLV
667
Saritha Boddupelli and Nageshwara rao A.S. / Procedia Engineering 127 (2015) 665 – 669 7DEOH&KHPLFDOFRPSRVLWLRQRIZRRGPDWHULDOV
$D
/S
=[
$R
3P
&V
7D
:W
(OHPHQWV SUHVHQWLQ ZRRG
6X
&U
&
+
1
2
6
3
+2
6L
)H
$O
%D
%
&G
&D
&X
3E
0J
1L
.
1D
=Q
6X6WHUFXOLDXUHQV$D$OEL]LDDPDUD/S/DJHUVWURHPLDSDUYLIORUD=[=L]\SKXV[\ORS\UXV$R$OEL]LDRGRUDWLVVLPD3W3WHURFDUSXV PDUVXSLXP&V&KORUR[\ORQVZLHWHQLD7D7HUPLQDOLDWRPHQWRVD:W:ULJKWLDWLQFWRULD&U&RFKORVSHUPXPUHOLJLRVXP
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
668
Saritha Boddupelli and Nageshwara rao A.S. / Procedia Engineering 127 (2015) 665 – 669
)LJ9DULDWLRQRIPDVVDWWHQXDWLRQFRHIILFLHQWZLWKHQHUJ\)LJ9DULDWLRQRI3KRWRHOHFWULFHIIHFWZLWKHQHUJ\
)LJ9DULDWLRQRI&RPSWRQVFDWWHULQJZLWKHQHUJ\
)LJ9DULDWLRQRI3DLUSURGXFWLRQVFDWWHULQJZLWKHQHUJ\
&RQFOXVLRQV ,WLVFRQFOXGHGWKDWWKHUHLVDVLJQLILFDQWYDULDWLRQLQWRWDOPDVVDWWHQXDWLRQFRHIILFLHQW,WYDULHVLQORZHQHUJ\DQG KLJKHQHUJ\UHJLRQVZKHUHDVWKHUHLVQRFKDQJHLQWKHPHGLXPHQHUJ\UHJLRQIURPNH9WR0H9IRUWKHZRRG PDWHULDOVDVFRPSDUGZLWKWKHVKLHOGLQJPDWHULDOV3EFRPSRXQGV ,QWKHPHGLXPHQHUJ\UHJLRQWKHYDOXHRI WRWDO LV WKH VDPH IRU DOO WKH ZRRG PDWHULDOV DW D JLYHQ HQHUJ\ OHYHO ,W LV EHFDXVH RI = GHSHQGHQW WRWDO DQG SDUWLDO DWWHQXDWLRQSURFHVVHV
5HIHUHQFHV *DOOHJR(/RUHQWH$9HJD&DUULOOR+5 7HVWLQJRIDKLJK±GHQVLW\FRQFUHWHDVQHXWURQVKLHOGLQJPDWHULDO1XFO7HFKQRO +XEEHOO-+3KRWRQPDVVDWWHQXDWLRQFRHI¿FLHQWVDQGHQHUJ\DEVRUSWLRQFRHI¿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
Saritha Boddupelli and Nageshwara rao A.S. / Procedia Engineering 127 (2015) 665 – 669 %XUPHVWHU$*DPPDUDGLDWLRQHIIHFWVRQFKHPLFDOPRUSKRORJLFDOSK\VLFDODQGPHFKDQLFDOSURSHUWLHVRISLQHDQGEHHFKZRRGV 0DWHULDOSUIXQJ $QWRLQH5&$YHOOD79DQ(\VHUHQ-&6WXGLHVRIZRRGWUHDWHGE\KLJKGRVHVRIȖUDGLDWLRQ ,$:$%XOO $QWRLQH 5& 9DQ (\VHUHQ -& ,QWpUrW GHV UD\RQV Ȗ GDQV OH SUȚWUDLWPHQW GHV ERLV HQ YXH GH OHXU DQDO\VH DX PLFURVFRSH j EDOD\DJH >0LFURVFRSLFVWXGLHVRIZRRGDIWHU*DPPDUDGLDWLRQ@ &5$FDG6F6p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omRGDGHQVLGDGHGHPDGHLUDVSRUDWHQXDomRGDUDGLDomRJDPDGHEDL[DHQHUJLD ,3()3LUDFLFDED 6KDNKUHHW%=%DXN67DMXGGLQ$6KXNUL$0DVVDWWHQXDWLRQFRHIILFLHQWVRIQDWXUDO5KL]RSKRUDVSSZRRGIRU;UD\VLQWKH± NH9UDQJH 5DGLDW3URW'RVLPHWU\ +XEEHOO-+%HUJHU0-3KRWRQFURVVVHFWLRQVRQDSHUVRQDOFRPSXWHU,QWHUQDO5HSRUW 1%6,5
669