Determination of Size and Mass Distribution of Aerosols

2009 ◽  
pp. 40-40-16
Author(s):  
A. Goetz ◽  
T. Kallai
Keyword(s):  
Mass Distribution

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

New approaches for the determination of dextran in the sugar production process

2018 ◽  
pp. 138-146 ◽  
Author(s):  
Karin Abraham ◽  
Eckhard Flöter
Keyword(s):  
Molecular Mass ◽  
Mass Distribution ◽  
Molecular Mass Distribution ◽  
Molecular Size ◽  
Mass Variation ◽  
Negative Effects ◽  
New Approaches ◽  
Precise Knowledge ◽  
Enzyme Application

The presence of polysaccharides in cane and beet raw juices causes several negative effects during the sugar manufacture. These are usually mitigated by enzymatic decomposition of dextrans. Such effects not only depend on the content, but also on the molecular mass distribution. This means that the different dextran fractions specifically affect the process. An accurate process control hence requires the most precise knowledge about the existing content and the molecular mass distribution present. A detailed understanding of the specific processing problems and also a targeted enzyme application hence requires the determination of a total dextran content and also its characterization including the differentiation between the different dextran fractions. An accurate analytical tool which equally satisfies industrial applicability is still lacking. To improve on this situation, two new approaches for the determination of dextran were developed and benchmarked against the commonly used and established Haze Method, which is rather inaccurate and also sensitive to molecular mass variation. The two new approaches are both based on polarimetry. These two methods indicate to be superior over the Haze Method with respect two molecular mass variation and hence enable the determination of a broader molecular size range including also low molecular mass dextrans.

Determination of the Charge and Mass Distribution in the Fission ofCf252

1971 ◽  
Vol 4 (5) ◽  
pp. 1913-1926 ◽  
Author(s):  
E. Cheifetz ◽  
J. B. Wilhelmy ◽  
R. C. Jared ◽  
S. G. Thompson
Keyword(s):  
Mass Distribution
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