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HOWlTT . ANALYSIS OF COPPER ARC BEA DS 60 970

50 -

E "~ 40-

.= ,~ 30-

20 -

10- ~

L0 . . . . i . . . . i . . . . t . . . . i . . . . i . 9650 soo 950 uo o ~250 ~4ooTemperature (~

FIG. l - -O xyg en solubi li ties in l iquid and sol id copper as a f imct ionof temperature, averaged from the compiled references in (13).

30 .

25 -

20 -

,~m 15-

~ ~o.

S-

I _0 . . . . i . . . . t . . . . f . . . . i . . . . i , ~200 400 600 800 10(20 1200 1~t00

Temperature (~F I G . 2- -T he temperature dependence o f the diffusion coefficients fo ro.~3'gen in copper, averaged fro m the comp iled r eferences in (13).

S u m m a r y a n d C o n c l u s i o n sI t i s c l e a r f r o m t h e e x t e n s i v e w o r k t h a t h a s b e e n d o n e o n t h e

s o l u b i l i t y o f g a s e s i n l i q u i d c o p p e r t h a t t h e A u g e r s p e c t r a , d e r i v e df r o m a r c b e a d s , c o n t a i n a b s o l u t e l y n o i n f o r m a t i o n p e r t in e n t t o t h ec a u s e o r o r i g i n o f a f i re . T h e l e v e l s o f g a s s o l u b i l i t y i n l i q u i dc o p p e r , e x e m p l i f i e d b y o x y g e n , a r e s e v e r a l o r d e rs o f r q a g n i t u d e

b e l o w t h e m i n i m u m a m o u n t s t h a t o n e c o u l d p o s s ib l y h o p e t o d e t ec tb y A u g e r a n a l y s i s . F u r t h e r m o r e , n e i t h e r t h e s o l u b i l i t y n o r t h e r a t eo f d i f f u s i o n o f a t m o s p h e r i c g a s e s a r e e x p e c t e d t o b e a n y g r e a t e ri n l i q u i d c o p p e r a t h i g h t e m p e r a t u r e t h a n t h e y a r e i n t h e s o l i d a tm u c h l o w e r t e m p e r a t u r e s . I n d e e d , t h e p r e m i s e t h a t a tm o s p h e r i cg a s c o n c e n t r a t i o n s a r e s o m e h o w t r a p p e d f o r p o s t e r i t y i n a c o p p e ra r c b e a d i s t o ta l ly w r o n g a n d b a s e d o n a m i s u n d e r s t a n d i n g o f th et h e r m o d y n a m i c a n d k i n e t i c b e h a v i o r o f t h is m a t e r i a l.A c k n o w l e d g m e n t s

T h e a u t h o r w o u l d l i k e t o t h a n k R a y B a c h t e l l f o r h e l p f u l d i s c u s -s i o n s a n d B r e n d a Z i m n y f o r p r e p a r i n g th e m a n u s c r i p t .R e f e r e n c e s

l . Ma cCleary RC, Tha ma n RN. U.S. Patent 4,182,959, (1980).2. And erson RN. Surface ana lysis of electr ical arc residues in f ireinves t iga tion . J Forens ic Sc i 1989;34(3) :633-7 .3 . Anderso n RN, Wolfe TA. Sc ien t i fi c examina t ion of e lec t rica l arcresidues to determine f ire cause. Fire Arson Invest 1992;42(3) :58-9 .4 . Anderson RN. Le t te r to the Edi to r , F i re A rson Inves t1994;45(2) :44-5 .5 . Fas t JD. In te rac t ion of meta l s and gases , Vol . 1 , the rmodyn amicsand phase re la t ions . New York: Academ ic Press 1965 .6. Butts A. Copp er9 Am erican Chem ical Society Mon ograph Series,New York : Re inhold Publ i sh ing Corp. , 1954.7. Sieverts A , Krum bhaa r W. Uber die 16slichkeit von gasen in met-al len und legierun gen. Ber Dtsch C hem Ges 1910;43(1):893-900.8 . Be land B. Exam ina t ion of a rc beads . F i re Arson Inves t 1994;44(4) :20-2 .9 . Oberg KE, Fr iedman LM, Boors te in WM , Rapp RA. The d i f fus iv ityand so lub i l i ty o f oxygen in l iqu id copper and l iqu id s i lver f romelec t rochemica l measurements . Meta l lu rg Trans 1973;4(1) :61-7 .10 . Kulkarn i AD. The thermodynam ic s tud ies o f l iqu id copper a l loys byelectromotive force method. Metallurg Trans 1973;4(7):1713-21911 . Seow HP, Biswas AK. Thermo dynam ic proper t ies o f oxygen inl iqu id copper. P roc A us t ra las ian Ins t Meta ls M in ing 1973;2 4 5 : 3 9 - 4 5 .12 . F i tzner K, Moser Z . A ct iv i ty o f oxygen in d i lu te l iqu id Cu-O a l loys .Metals T echno l 1979;6(7):273-5.1 3. F r o m m E , H e h n W , J e h n H , H r r z G . P h y s i k D a t e n - - G a s e s a n dCarbon in Meta l s (Therm odynamics , Kine t ics and Propert ies ), P t .XXI: Group 1B Metals (1) Copper (Cu). Stuttgart : Max-Planck-Inst i tut fur Metalforschung, Inst i tut fur Werkstaffwissenschaften,1984.14 . Wada T , Fuek i K, M ukaibo T . Dete rmina t ion of the so lub i l i ty o foxygen in .copper by the cou lomet r ic method . Bul l Chem SocJapan 1976;49(11) :3317-8 .15 . Horr igan VM. T he so lub i l i ty o f oxygen in so l id copper. M eta l lu rgTrans A 1977;8A(5) :785-7 .16 . Otsuka S , Kozuk a Z . The d i f fus iv i ty o f oxygen in l iqu id copper

by e lec t rochemica l measurements . Meta l lu rg Trans B 1976;7B(3): 147-9 .Addi t iona l in form at ion and repr in t reques ts :Dr . David G. Howi t tDepar tment o f Chem ica l Engineer ing and Mater ia l s Sc ienceUnivers i ty o f C a l i fo rn iaDavis , CA 95616