230
FRIEDLANDER AND PASCERI
range) fell on a straight line on semilog paper. At low magnifications
(larger size range), the data followed a linear relation on log—log
paper,
at least through the most reliable data points. Analytical ex-
pressions for X(r) were obtained from these figures. The expressions
were differentiated and divided by —k,A7 to yield n(r). The deposition
velocity k, had an awkward form but was approximated by two simple
expressions of the type k,~ r? for the two size ranges examined. The
final expressions for n(r) are given ig Table 1.
Table 1— FORMULAS FOR ate OFRUNS10 AND 11
Run 11
+f
;
-_F-o6 x. 10%. ewi25.4 pth
29°
22(0. 0035'< r < 0.019 yw)
ee22 x20 pateT,
sale
ca
. LS tag
2
i
3
ow
;
“Se
5.
a _
WEee
Swit the vertical barsFapgesenting:
55
ments.
The orfohaiddiethe coritamination.on the grids used ferruns 10 and
11 was checked with blank,gridayIt was found that the partié
tamination, level present before sampling_was, always less than:3%, of
the total partfgle count madeat each magnification.
ts
¥
10
rT
LOW
MAGNIFICATION
LOW
MAGNIFICATION
2
n(r), PARTICLES/CM3-
r— HIGH
MAGNIFICATION
—
-— HIGH
MAGNIFICATION
109
1078
|
|
|
107?
tM
107!
Fig. 5—Size distribution functions for runs 10 and 11. The number of
particles in the vange between ry and r+ dy is given by n(r) dr. The
distribution peaks near radii of 0.02 and 0.01 wu.