• Journal of Power System Engineering
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• v.17 no.6
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• pp.63-72
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• 2013

The main purpose of this study is to analyze the collection characteristics of multi-layer multi-stage porous plate system with ionizer and dielectric-substance experimentally. The experiment is carried out to analyze the characteristics of pressure drop and collection efficiency for the present system with experimental parameters such as applied voltage, inlet velocity, stage number and inlet particle concentration, etc. In results, for multi-layer multi-stage porous plate system of inflow type, at 5 stage and $v_{in}$=2.58 m/s, the pressure drop becomes lower 15 $mmH_2O$ as 95 $mmH_2O$ than that of non-inflow type system. It is estimated that for the present system with ionizer and dielectric-substance, the collection efficiency represents 98.5% showing higher 5.2% comparing to that of multi-layer multi-stage porous plate system without ionizer and dielectric-substance at 5 stage, $v_{in}$=2.58 m/s and inlet concentration $3g/m^3$(fly ash).

• Journal of Power System Engineering
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• v.18 no.3
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• pp.42-50
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• 2014

The main object of this study is to investigate the collection characteristics of wet-type multi-layered and multi-staged porous plate system experimentally. The experiment is carried out to analyze the characteristics of pressure drop and collection efficiency for the present system with the experimental parameters such as water spray, inlet velocity, stage number and inlet particle concentration, etc. In results, for the present system of wet-type, the pressure drop represents 158 $mmH_2O$ higher 3% than that in dry-type at 5 stage and $v_{in}$=3.53 m/s. In case of 5 stage, $v_{in}$=3.53 m/s and water spray 250 ml/min, the collection efficiency of the present system becomes significantly higher as 99.7% comparing to that of the conventional wet-type scrubber. Additionally, for 5 stage and 250 ml/min, $SO_2$ removal efficiencies decrease with the increment of inlet velocity representing 75.0, 62.5, 50.0%, at $v_{in}$=2.12, 2.82, 3.53 m/s, respectively.

• Advances in Computational Design
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• v.5 no.3
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• pp.261-276
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• 2020

The reasonable layout of vacuum cleaner can effectively improve the collection efficiency of iron filings generated in the process of steel production. Therefore, in this study, the CFD-DEM coupling model and two-fluid model are used to calculate the iron filings collection efficiency of vacuum cleaner with different inclination/cross-sectional area, pressure drop and inlet angle. The results are as follows: The CFD-DEM coupling method can truly reflect the motion mode of iron filings in pneumatic conveying. Considering the instability and the decline of the growth rate of iron filings collection efficiency caused by high pressure drop, the layout of 75° inclination is suggested, and the optimal pressure drop is 100Pa. The optimal simulation results based on two-fluid model show that when the inlet angle and pressure drop are in the range of 45°~65° and 70Pa~100Pa, larger mass flow rate of iron filings can be obtained. It is hoped that the simulation results can offer some suggestion to the layout of vacuum cleaner in the rolling mill.

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1505-1515
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• 2009

A new method to semicontinuously determine $PM_{2.5}$ ionic species with a short time resolution is described in detail. In this system, a particle collection section (mixing part, particle collection chamber, and air/liquid separator) was developed. A Y-type connector was used to mix steam and an air sample. The particle collection chamber was constructed in the form of a helix coil and was cooled by a water circulation system. Particle size growth occurred due to the high relative humidity and water absorbed particles were efficiently collected in it. Liquid samples were drained out with a short residence time (0.08-0.1 s). The air/liquid separator was also newly designed to operate efficiently when the flow rate of the air sample was 16.7 L $min^{-1}$. For better performance, the system was optimized for particle collection efficiency with various types of test aerosols such as ($NH_4)_2SO_4,\;NaCl,\;NH_4HSO_4,\;and\;NH_4NO_3$. The particle collection efficiencies were almost 100% at different concentration levels in the range over 500 nm in diameter but 50-90% in the range of 50-500 nm under the following experimental conditions: 15 coil turns, a water flow rate for steam generation of 0.65 mL $min^{-1}$, and an air sample flow rate of 16.7 L $min^{-1}$. Finally, for atmospheric applications, chemical compositions of $PM_{2.5}$ were determined with a time resolution of 20 min on January 11-24, 2006 in Seoul, Korea, and the chemical characteristics of $PM_{2.5}$ ions were investigated.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.310-317
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• 1999

This paper presents study of collection performance according to dropper spacing for catenary Static characteristics analysis, dynamic simulation, stress and wear analysis for different 5 catenary configurations according to dropper spacing are performed. And collection performance for TGV-Nord catenary system is also analyzed in order to compare and evaluate.

• Korean Journal of Veterinary Service
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• v.44 no.4
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• pp.217-225
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• 2021

We investigated the effect of temperature and stock density on the collection efficiency of oral fluid in the pig farm in Korea. Three pig farms with similar breeding environmental conditions were selected and four pens of each farm (total 12 pens) were tested for the collection efficiency of oral fluid from pigs. Collection rate was considered as significant when oral fluid was collected from 70% of pigs within a pen. In the case of growing pigs, when internal temperature of pig barn increased by one designated degree (5℃), the oral fluid collection rate significantly decreased by 24.7% (P<0.05). The collection rate of oral fluid also decreased by 7.1% (P<0.05) as the density rate increase by one designated degree (12.5%). It was estimated that the collection efficiency of oral fluid decreased when the internal temperature of pig barn was 30℃ or higher, or barn density is higher 25% or high. On the other hand, in the case of stall-housing sows, unlike growing pigs, there was no significant differences according to the temperature, so oral fluid collection was considered to be efficient even in hot season.

• Particle and aerosol research
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• v.17 no.2
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• pp.21-27
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• 2021

We developed non-metallic electrodes that can replace metallic electrodes of the electrostatic precipitator(ESP) for the purpose of light weight, corrosion resistance, cost reduction. We manufactured three types of collection electrodes made of stainless steel (M), Carbon ink coating layer-Plastic sheet-Carbon ink coating layer (CPC), and Plastic sheet-Carbon ink coating layer-Plastic sheet (PCP). We studied the collection efficiency of a two-stage ESP using oil mist particles with and without collection stage by changing the flow rate, the material of collection electrode, and the applied voltage of the pre-charger module and the collection module. Here we measured concentrations of particles at diameters of 0.45 ㎛ (CMD; count median diameter) and 3.0 ㎛ (MMD : mass median diameter), as well as PM_2.5 and PM₁₀. As a result of the experiment, two-stage ESP had 22~25% higher collection efficiency in PM_2.5 than one-stage ESP at the same applied voltage. The difference in collection efficiency by varying the materials of collection electrodes was less than 5%. The weight of the non-metallic electrode was only one eighth the weight of the metal electrode. CPC electrode had a thickness of 0.27 mm, which was 1.5 times thinner than a thickness of PCP electrode, so when the flow rate increased, the CPC electrodes couldn't be kept at equal intervals due to the fluttering unlike PCP electrodes. In addition, the PCP-CPC collection module of the present experiment followed the theoretical efficiency based on Deutsch equation and Cochet's charging theory.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.70-79
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• 1998

This study was conducted to understand the effects of weather and tapping date on yield and quality of lactree(Rhus verniciflua) sap yield showed a significant positive correlation with the minimum temperature of one day before sap collection at 1% level and with theminimum humidity of theday of sap collection at 5% level. However, the differences between the maximum and the minimum temperatures and humidities of the day of sap collection were negatively correlated with the sap yield at 5% level. Multiple regression analysis indicated that the minimum temperature of one day bofore sap collection and the minumum humidity of the day sap collection were important factors for increasing sap yield. The high sap yield of lactree by Japanese tapping method was recorded during mid-July and early August. Seasonal variation in lactree sap constituents was observed. The sap collected on 15th of August contained the highest urushiol content (68.3%) and the lowest water content resulting in high quality of lactree sap. By reversed-phase HPLC analysis, fove urushiol components were separated from each other depending on the number of doulbe bonds in the side-chain , and seaxonal variation of urushiol composition was noticed. The 3-C15 triene content fo the sap collected on 5th of July was the highest(77.56%) indicating the major component of urushiol which affects lactree sap quality.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.337-345
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• 2009

World leading national science technology information institutes provide scientists with R&D information for increasing national competitiveness. Collection development policy is the guidelines for the science technology information institutes that identify information resources and connect them together to build an information network for supporting R&D. In order to draw main elements of the collection development policy for national level science and technology information institutes, this paper analyzed the policies of National Library of Medicine (NLM), British Library (BL), Canada Institute for Scientific and Technological Information (CISTI), and Korea Institute of Science and Technology Information(KISTI). The results of this study can be used as the guidelines for the science and technology information institutes for establishing collection development policy.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.4
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• pp.545-552
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• 2015

The main object of this study is to investigate the collection characteristics of an electro-static multi-staged impaction system, experimentally. The experiment is carried out to analyze the characteristics of pressure drop and collection efficiency for the present system with the experimental parameters such as the inlet velocity, stage number, applied voltage and shape of discharge electrode, etc. In results, the pressure drop is shown below $148mmH_2O$ lower than that of the conventional bag filter at inlet velocity 3.46 m/s and 5 stage. For 5 stage, the collection efficiencies are to be 97.4, 99.0% with the applied voltage 0 kV at the inlet velocity 2.07, 3.46 m/s, while 98.4, 99.9% with 40 kV of a sharp edge discharge electrode. Additionally, the present system is to be considered as an effective compact system for a removal of particulate pollutants from marine diesel engines due to much higher collection efficiency and appropriate pressure drop.