Document text
Machine-read from the scan, so expect some errors. Lines that couldn’t be read are left out.
Page 1
subject: Particle Deposition from Dust Clouds at Various Altitudes 1* The oalculations dealing with the rate of descent of small dust particles through the atmosphere,are attatched to this memo* 2« It was found that the ratio of the rate of descent at 50,000 ft* to that 5* The approximations used in obtaining this answer and their justifications are described on page 5* BEST AVAILABLE COPY
Page 2
BEST AVAILABLE COPY WORK SHEET: CALCULATION OF v 38000 640 n If II It n 40000 582 it If It ft n • 44000 481 it II II it n BEST AVAILABLE COPY BEST AVAILABLE COPY
Page 3
BEST AVAILABLE COPY 1. Data on the temperature and density of air are taken from the National were constructed on the basis of the mean atmospheric pressure and temperature at sea level and 10° N. latitude. From these values the temperatureC.s and pressures at the other altitudes were calculated. 2. Values for the viscosity of air at various temperatures were taken from on graph paper and the resulting curve (see page 4) was found to be linear in the temperature range involved. However, the data leave much to be desired in the way of accuracy; though the extreme values of >1 as reported in the tables would not affect the validity of our results. 3. It was assumed that the acceleration due to gravity was constant. The basis of this statement is the equation: the decrease in g is less than of the value at sea level. 4. liillikarfs modification of Stakes' Lav/ is not n.eded here. It was found that for values of l/a less than 0,4 (1 n the n.f.p. of the molecules of the gas, a - the radius of the spherical particle), Stokes' Law in its original form could be used. Taking the m.f.p. of nitrogen as that com ponent of air having the largest m.f.p. at -55° C., and particles of 100,**'in diameter, l/a is less than 0.4; hence vie were justified in our use of the unmodified formula. BEST AVAILABLE COPY
Page 8
Logar ith m ic ,3xHCyc le s, '%r BEST AVAILABLE COPY BEST AVAILABLE COPY
Page 10
BEST AVAILABLE COPY SAMPLE........................................................ Shelf....................... Tube.. Counted for:..................................................................... Interval between counting cycles.. BEST AVAILABLE COPY Counts Pee Standees Aik Init. Fin. Tot. Minute BEST AVAILABLE COPY S7
Page 12
BEST AVAILABLE COPY BEST AVAILABLE COPY 6 Nov. 19^5 BEST AVAILABLE COPY
Page 15
M illim e te ra, 10th lin ed heavy BEST AVAILABLE COPY BEST AVAILABLE COCOPY BEST AVAILABLE COPY
Page 18
BEST AVAILABLE COPY BEST AVASLABLE COPY ICO hours ajfer BEST AVAILABLE COPY
The text continues in the original scan (19 pages).