scholarly journals The Inversion Method for Determining the Particle Size Distribution from the Scattered Light Intensity Pattern in a Laser Droplet Sizer

1983 ◽  
Vol 19 (10) ◽  
pp. 819-825
Author(s):  
Kyoichi TATSUNO
Author(s):  
T. Okada ◽  
Y. Ishizu ◽  
K. Matsunuma

AbstractA new method for determining particle-size distribution of cigarette smoke particles was developed by simultaneous measurement of scattered light at three angles for a fixed wavelength. A theoretical chart useful for this purpose, which was made of the relative intensities of scattered light at the angles 45° and 135° to that at the angle 90°, was calculated on the basis of the Mie theory. The number concentration was determined from the Rayleigh ratio using the working standard method. The measurements were rapidly performed, without change of particle size during measuring time, with a device for dilution. The geometric mean diameter, the logarithmic standard deviation and the number concentration of mainstream smoke were found to be about 0.18 um, 0.4 and 3 X 10


Author(s):  
D. W. Burr ◽  
K. J. Daun ◽  
K. A. Thomson ◽  
G. J. Smallwood

In multiangle elastic light scattering (MAELS) experiments, the morphology of aerosolized particles is inferred by shining collimated radiation through the aerosol and then measuring the scattered light intensity over a set of angles. In the case of soot-laden aerosols MAELS can be used to recover, among other things, the size distribution of soot aggregates. This involves solving an ill-posed set of equations, however. While previous work focused on regularizing the inverse problem using Bayesian priors, this paper presents a design-of-experiment methodology for identifying the set of measurement angles that minimizes its ill-posedness. The inverse problem produced by the optimal angle set requires less regularization and is less sensitive to noise, compared with two other measurement angle sets commonly used to carry out MAELS experiments.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhenzong He ◽  
Liang Xu ◽  
Junkui Mao ◽  
Xingsi Han ◽  
Biao Zhang

Aerosol concentration in the flow is usually time varying, and aerosol particle size distribution (PSD) is considered to be unchanged, which increases the difficulty of the measurement of aerosol PSD and concentration online. To solve these problems, a kind of multistep inversion method based on the angular light-scattering (ALS) signals is proposed. First, the aerosol PSD is estimated using shuffled frog-leaping algorithms (SFLAs) from relative ALS signals. Then, with aerosol PSD as priori information, the aerosol concentration is obtained by the Kalman filter (KF) algorithm, widely used in the real-time control system of industrial facilities for its ability of fast predictions. The result reveals that the performance of the improved SFLA is better than that of the original SFLA in solving the aerosol PSD. Moreover, in studying the aerosol concentration, more accurate results can be obtained with larger standard deviation of process noise or smaller standard deviation of measurement noise, while decreasing sampling time interval can improve the accuracy of retrieval results and reduce time delay to a certain degree. So, to improve retrieval accuracy, the noise should be controlled, and appropriate sampling time interval should be selected. All the numerical simulations confirm that the methodology provides effective and reliable results in real-time estimating.


2010 ◽  
Vol 28 (No. 1) ◽  
pp. 36-43
Author(s):  
P. Sladký ◽  
R. Koukol

The hazes of freshly bottled and aged pale lager beers determined with the 12° and 90° dual angle laboratory hazemeters and 10° to 90° range photogoniometer were compared and evaluated. The instruments were standardised in EBC formazin units. In freshly bottled beer, the forward (12°–25°) haze values were smaller approximately by a factor of three than the nephelometric (90°) values which yielded 0.33 EBC units. In aged beer, the forward haze was greater than the nephelometric one. Whereas the aged beer showed the greatest and the fresh beer the lowest intensity of scattered light, the formazin suspension intensity was in between. Due to the standardisation of the beer scattered intensities by relation to that of formazin, the standardised nephelometric haze in non-aged beer was greater than the forward haze, and vice versa in aged beer. The greater forward than the nephelometric haze in aged beer was caused by the growth of haze particles above the mean size of formazin particles which was larger than 2 μm as confirmed by the particle size distribution measurement.


2009 ◽  
Vol 45 (10) ◽  
pp. 3981-3984 ◽  
Author(s):  
Gang Lei ◽  
K.R. Shao ◽  
Y.B. Li ◽  
G.Y. Yang ◽  
Youguang Guo ◽  
...  

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