• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2230-2237
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• 2020

Self-priming venturi scrubber is one of the most effective devices used to collect aerosols and soluble gas pollutants from gaseous stream during severe accident in a nuclear power plant. The present study focuses on investigation of dust particle removal efficiency of the venturi scrubber both experimentally and theoretically. Venturi scrubber captures the dust particles in tiny water droplets flowing into it. Inertial impaction is the main mechanism of particles collection in venturi scrubber. The water injected into venturi throat is in the form of jets through multiple holes present at venturi throat. In this study, aerosols removal efficiency of self-priming venturi scrubber was experimentally measured for different operating conditions. Alumina (Al₂O₃) particles with 0.4-㎛ diameter and 3950 kg/㎥ density were treated as aerosols. Removal efficiency was calculated for different gas flow rates i.e. 3-6 ㎥/h and liquid flow rates i.e. 0.009-0.025 ㎥/h. Experimental results depict that aerosols removal efficiency increases with the increase in throat velocity and liquid head. While at lower air flow rate of 3 ㎥/h, removal efficiency decreases with the increase in liquid head. A theoretical model of venturi scrubber was also employed and experimental results were compared with mathematical model. Experimental results are found to be in good agreement with theoretical results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.983-989
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• 2013

The current research reviewed the design conditions that would maximize the efficiency of the hybrid collector that combines in one unit "cyclone-inertial impaction-bag filter". The computational analysis for the shape of cyclone entry predicts that a design that installs the guide vane at the entry of the tangential type cyclone brings a high-rpm and powerful vortex, very effective in promoting the deflection of coarse particles from the streamline at the cyclone. As the lower part of the cyclone is venturi-shaped, however, a strong flow downward of 4 to 5 m/sec persists through the lower part of the hopper, revealing the likely reentrainment of collected dust. And the removal of the venturi at the lower part of the cyclone would solve the problem of the reentrainment of collected dust. The acceleration of the flow velocity through the adjustment of the gap of the collision baffle would increase the effect of collision, but as the interference with the dust separation is expected, the original design should be kept for the baffle.

• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1202-1207
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• 2003

Using a recently developed Hybric Plasma-Particle Accelerating Impact Deposition (HP-PAID) process, synthesis of nanostructured silicon coatings has been investigated by injecting vapor-phase TEOS (tetraethosysilane, (C$_2$H$\_$5/O)$_4$Si) into an Ar hybrid plasma. The plasma jet with reactants was expanded through nozzle into a deposition chamber, with the pressure dropping from 700 to 10 torr. Ultrafine particles accelerated in the free jet downstream of the nozzle, deposited by an inertial impaction onto a temperature controlled substrate. By using this process, nanostructured amorphous silicon coatings with grain size smaller than 10 nm could be synthesized. These samples were annealed in an Ar and crystallized at 900$^{\circ}C$ for 30 min. TEM analysis showed that the annealed coatings were also composed of nanoparticles smaller than 10 nm, which showed a good consistency that the average grain size of 7 nm was also estimated from a peak shift of 2.39 cm$\^$-1/ and Full Width at Half Maximum (FWHM) 5.92 cm$\^$-1/ of Raman analysis. The noteworthy is that a strong PL peak at 398 nm was also obtained for this sample, which indicates that the deposited coatings also contained 3∼4 nm nanostructured grains.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2485-2491
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• 2009

Culture was performed by using Sheep Blood Agar Plate (BAP, Asan Pharmaceutical) and Sabouraud Dextrose Ager (SDA, Asan Pharmaceutical) along with air $IDEAL^{TM}$ (Biomerieux), which is a microbe interceptor based on inertial impaction interception, in order to investigate bioaerosol in indoor and outdoor air at five elderly care facilities in a metropolis and an urban-rural consolidated city for two months from April 1 to May 31, 2007. From the culture followed by isolation and identification, the following conclusions were drawn. 1. As for the general isolation of microbes in each facility, care center S had the largest amount of microbes (263 cfu/$m^3$) isolated in a 300L room, followed by care center U having 123 cfu/$m^3$ isolated. 2. As for the number of bacteria isolated from a medium intercepting 300 L indoor, the largest amount of other unidentified or non-pathogenic Gram positive cocci (321 cfu/$m^3$) was isolated and most of the other Gram positive cocci were CNS (Coagulase Negative Staphylococcus). 3. As for the number of fungi isolated from a medium intercepting 300 L in a room, the largest number of Aspergillus spp. (66) was isolated, followed by Mucor spp. (62 cfu/$m^3$), Penicillium spp. (53 cfu/$m^3$), Alternaria spp. (50), and other unidentified or non-pathogenic fungi (42 cfu/$m^3$). 4. As for the rate of indoor and outdoor pollution, the average number of interceptions was all larger indoor than outdoor; the research differentiating the amount of air into 300 L and 500 L demonstrated that the larger amount of air led to more bacteria, making no great variation in the species.