scholarly journals ESTIMATION METHOD OF PARTICLE SIZE DISTRIBUTION (PSD) OF RADIOACTIVE AEROSOLS BY USING INERTIAL SEPARATORS

2018 ◽  
Vol 3 (3) ◽  
pp. 327
Author(s):  
Youesf Husein ◽  
Pripachkin Dmitry ◽  
Budyka Aleksandr ◽  
Karev Andrey ◽  
Tsovyanov Aleksandr

This paper describes a new method for determining the dispersed composition of radioactive aerosols using device that containing inertial separators of aerosol particles which separating it into fractions by size.

Author(s):  
P. J. Connolly ◽  
G. B. McFiggans ◽  
R. Wood ◽  
A. Tsiamis

We investigate the sensitivity of marine cloud brightening to the properties of the added salt particle distribution using a cloud parcel model, with an aim to address the question of, ‘what is the most efficient particle size distribution that will produce a desired cooling effect?’ We examine the effect that altering the aerosol particle size distribution has on the activation and growth of drops, i.e. the Twomey effect alone, and do not consider macrophysical cloud responses that may enhance or mitigate the Twomey effect. For all four spray generation methods considered, Rayleigh jet ; Taylor cone jet ; supercritical fluid ; and effervescent spray , salt particles within the median dry diameter range D m =30–100 nm are the most effective range of sizes. The Rayleigh jet method is also the most energy efficient overall. We also find that care needs to be taken when using droplet activation parametrizations: for the concentrations considered, Aitken particles do not result in a decrease in the total albedo, as was found in a recent study, and such findings are likely to be a result of the parametrizations' inability to simulate the effect of swollen aerosol particles. Our findings suggest that interstitial aerosol particles play a role in controlling the albedo rather than just the activated cloud drops, which is an effect that the parametrization methods do not consider.


Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1669
Author(s):  
Jianlin Ren ◽  
Junjie He ◽  
Jiayu Li ◽  
Junjie Liu

The SARS-CoV virus spreads in the atmosphere mainly in the form of aerosols. Particle air filters are widely used in indoor heating, ventilation, and air-conditioning (HVAC) systems and filtration equipment to reduce aerosol concentration and improve indoor air quality. Requirements arise to rate filters according to their mass-based filtration efficiency. The size distribution of test aerosol greatly affects the measurement results of mass-based filtration efficiency and dust loading of filters, as well as the calibration of optical instruments for fine-particle (PM2.5) mass concentration measurement. The main objective of this study was to find a new method to generate a chemically nontoxic aerosol with a similar particle size distribution to atmospheric aerosol. We measured the size distribution of aerosols generated by DEHS (di-ethyl-hexyl-sebacate), PSL (poly-styrene latex), olive oil, and 20% sucrose solution with a collision nebulizer in a wide range of 15 nm–20 μm. Individually, none of the solutions generated particles that share a similar size distribution to atmospheric aerosol. We found that the 20% sucrose solution + olive oil mixture solution (Vss:Voo = 1:2) could be used to generate a chemically nontoxic aerosol with similar particle number/volume size distribution to the atmospheric aerosol (t-test, p < 0.05). The differences in the mass-base filtration efficiency measured by the generated aerosol and the atmospheric aerosol were smaller than 2% for MERV 7, 10, 13, and 16 rated filters. The aerosol generated by the new method also performed well in the calibration of optical-principle-based PM2.5 concentration measurement instruments. The average relative difference measured by a tapered element oscillating microbalance (TEOM) and a Dusttrak Model 8530 (calibrated by aerosol generated by the new method) was smaller than 5.8% in the real-situation measurement.


2015 ◽  
Vol 4 (1) ◽  
pp. 30-34
Author(s):  
Rondang Tambun ◽  
Nofriko Pratama ◽  
Ely ◽  
Farida Hanum

Particle size measurement of wheat flour is important in wheat flour industry. There are several methods have been used to measure particle size distribution (PSD) of wheat flour, such as Andreasen pipette method, sedimentation balance method, centrifugal sedimentation method. The disadvantages of these methods are that they are time consuming and require special skills. On the other hand, PSD can be analyzed using a different principle through laser diffraction/scattering methods, and coulter counter method. The laser diffraction/scattering and coulter counter methods produce highly accurate results within a shorter time, but the equipment is extremely expensive. Therefore, a simple and cost-effective new method to determine PSD is in high demand. In this study, we aim to develop a new method to measure the particle size distribution of wheat flour using a buoyancy weighing–bar method. In this method, the density change in a suspension due to particle migration (wheat flour) is measured by weighing buoyancy against a weighing–bar hung in the suspension (etanol/metanol), and the PSD is calculated using the length of the bar and the time–course change in the mass of the bar. This apparatus consists of an analytical balance with a hook for underfloor weighing, and a weighing–bar, which is used to detect the density change in suspension. The result obtained show that the PSD of wheat flour measured by the buoyancy weighing-bar method is comparable to that determined by settling balance method.


1980 ◽  
Vol 51 (4) ◽  
pp. 516-520 ◽  
Author(s):  
R. J. Tropp ◽  
P. J. Kuhn ◽  
J. R. Brock

Nature ◽  
1984 ◽  
Vol 311 (5987) ◽  
pp. 648-651 ◽  
Author(s):  
N. R. J. Fieller ◽  
D. D. Gilbertson ◽  
W. Olbricht

Sign in / Sign up

Export Citation Format

Share Document