Cosmic dust in the stratosphere

Abstract

A b a l l o o n borne technique f o r s t r a t o s p h e r i c c o l l e c t i o n of micron s i z e d u s t from up t o a m i l l i o n cubic m e t e r s of a i r has been developed. The technique samples p a r t i c l e s i n s i z e range of roughly 1-100 microns and t h u s t h e extraterrestrial p a r t i c l e s i n t h i s s i z e range which do n o t burn up during t h e i r e n t r y i n t h e e a r t h ' s atmosphere a r e collected. The c o l l e c t i o n made &;ring t h e maximum a c t i v i t y of e a r l y June meteor showers i n 1 9 6 6 , i n d i c a t e s t h a t the t o t a l t e r r e s t r i a l a c c r e t i o n i n t h i s s i z e range c e r t a i n l y does n o t exceed 550 t o n s per clay and i s probably less t h a n 50 t o n s p e r day over t h e whole e a r t h . -

Global air pollution and climatic change

“…Meteoric debris.' Collection of extraterrestrial material in the size range of 1-100 um in diameter with rockets and other methods in 1969 showed that the total terrestrial accretion of particles does not exceed 550 tons/day and is probably less than 50 tons/day [Bhandari et al, 1968]. However, Rosen [1969] predicted that the mass flux of stratospheric dust of large particles over the earth would be of the order of 1-10 Mt/yr.…”

Continental dust in the atmosphere of the Eastern Equatorial Pacific

“…Past experience with collectors of this type [Bhandari et al, 1968;Delany et al, 1967;Parkin et al, 1967;Prospero, 1968] indicates that the assumed 50% efficiency is high and that the collection efficiency drops off rapidly for particles smaller than several microns in diameter. Because of the uncertainties involved, the 50% value will be used with the understanding that the dust loadings calculated in this manner will most likely be low.…”

“…A comparison of the size distribution for our samples with the so-called 'classical' continental aerosol distribution [Yunq½, 1963] suggests that the dust is relatively deficient in the smallersized particles. Whereas this disparity may actually reflect, in part, a true characteristic of an 'aged' continental dust that has traveled a considerable distance, it is most likely due primarily to a decrease in collection efficiency of the mesh with decreasing particle size [Bhandari ½• al., 1968], as discussed earlier. In addition, since the chlorox treatment does not destroy all the organic material in the sample, the peak may to some extent be caused by small particle aggregation.…”

Application of Mixture Design Using Diluted Acid for Extraction of Inorganic Components in Fruits of Casearia fasciculata and Determination by ICP OES: Evaluation by PCA and HCA

“…Low RCC values in organic digests contribute to reduce spectral interferences from the residual carbon and to improve analysis accuracy. 30 In this study, the maximum point obtained by the RCC evaluation is characterized as a saddle condition, that is, an intersection region between a relative minimum and a relative maximum. 29 The coordinates of the saddle point do not present ideal conditions for the studied system and the critical values for one or more variables may be comprised outside the delimited experimental domain.…”