• Title/Summary/Keyword: Particle charging

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Charge Distribution of Submicron Particles Charged by Spray Electrification or Corona Discharge (분무 및 코로나 방전에 의해 대전된 서브마이크론 입자의 대전량 분포)

  • Lee, Jae-Bok;Bae, Gwi-Nam;Hwang, Jeong-Ho;Lee, Gyu-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.1
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    • pp.124-132
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    • 2001
  • This paper reports on the charge distribution measurements of submicron particles for three different charging mechanisms, which are spray electrification, bipolar ionization and corona discharge process, respectively. The number of elementary charges per particle was investigated by classifying and counting of a discrete mobility class. Charge distribution measurements were performed with NaCl particles generated from a collision atomizer for 0.01, 0.1, 1% NaCl solutions. Experimental results show than charge level of atomized NaCl particles is high and decreases with increasing the dissolved ion concentration. The charge level of the atomized NaCl particles can be reduced to that o Boltzmann equilibrium conditions by the bipolar ionization(Po(sup)210 bipolar ionizer). The charge level on NaCl particles passing through the corona discharge reactor is much higher than those of atomized or bipolar ionized NaCl particles. The evaluation of these measurements results in charge distribution of the submicron particles.

Study on Discharge Electrode Design applied for Road Tunnel (터널용 전기집진시스템 개발을 위한 방전극 설계)

  • Kim, Jong-Ryul;Weon, Jong-Oung;Jang, Chun-Man
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.1238-1243
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    • 2009
  • As Social Overhead Capital(SOC) has been expanded, the highway road construction has been accelerated and city road system has been more complicated. So, long road tunnels have been increased and traffic flow rate also has been raised. Accordingly, the exhausting gas of vehicle cars seriously deteriorates the tunnel inside air quality and driving view. In order to improve tunnel inside air quality, it is needed to introduce a compulsory ventilation system as well as natural ventilation mechanism. The former, that is, a special compulsory ventilation facility is very useful and helpful to prevent a tunnel of being contaminated by traffic in most case. In the case of obtaining clearer and longer driving view, the ventilation systems have to be considered in order to remove floating contaminants or exhaust gas from engines. In this paper, discharge electrode design technology will be discussed.

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Fault Diagnosis of Transformer Based on Self-powered RFID Sensor Tag and Improved HHT

  • Wang, Tao;He, Yigang;Li, Bing;Shi, Tiancheng
    • Journal of Electrical Engineering and Technology
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    • v.13 no.5
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    • pp.2134-2143
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    • 2018
  • This work introduces a fault diagnosis method for transformer based on self-powered radio frequency identification (RFID) sensor tag and improved Hilbert-Huang transform (HHT). Consisted by RFID tag chip, power management circuit, MCU and accelerometer, the developed RFID sensor tag is used to acquire and wirelessly transmit the vibration signal. A customized power management including solar panel, low dropout (LDO) voltage regulator, supercapacitor and corresponding charging circuit is presented to guarantee constant DC power for the sensor tag. An improved band restricted empirical mode decomposition (BREMD) which is optimized by quantum-behaved particle swarm optimization (QPSO) algorithm is proposed to deal with the raw vibration signal. Compared with traditional methods, this improved BREMD method shows great superiority in reducing mode aliasing. Then, a promising fault diagnosis approach on the basis of Hilbert marginal spectrum variations is brought up. The measured results show that the presented power management circuit can generate 2.5V DC voltage for the rest of the sensor tag. The developed sensor tag can achieve a reliable communication distance of 17.8m in the test environment. Furthermore, the measurement results indicate the promising performance of fault diagnosis for transformer.

A Study on the Positively Charged Filter for Removing Fine Particles in Water (양전하가 부가된 수처리 필터의 입자제거특성에 관한 연구)

  • Jung, Sung-Hak;Kim, Jong-Won;Kim, Sang-Hee;Jeon, Byung-Heon;Lee, Seung-Gap;Lee, Jae-Keun;Ahn, Young-Chull
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.5
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    • pp.454-460
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    • 2012
  • The purpose of the present work is to investigate the removal characteristics of positively charged filters for capturing negatively charged particles such as bacteria and virus in water. In order to reduce the pressure drop and increase the filtration efficiency, the filter media, modified by charge modifier having positive functional groups, is developed and evaluated. Improved liquid filters have been developed with the modified surface charge to capture and adsorb particles by electrokinetic interaction between the filter surface and particles contained in an aqueous liquid. The positively charged filter media is composed of glass fiber, cellulose and poly-ethylenimine resin for positively charging with the variation of volume ratio. The zeta potential value of the positively charged filter is +37.92 mV at the glass fiber and cellulose content ratio of 50 : 50 with resin content of 100%, while that of the PSL test particle is -23.5 mV at pH 7. The removal efficiency of the electro-positively charged filter is 98% for PSL particles of 0.11 ${\mu}m$, while that of the negatively charged filter is 7%. The positively charged filter media showed the potential to be an effective method for removing fine particles from the contaminated water for liquid filtration.

Study on Dust Explosion Characteristics of Acetylene Black (Acetylene Black의 분진폭발 특성 연구)

  • Jae Jun Choi;Dong Myeong Ha
    • Journal of the Korean Society of Safety
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    • v.39 no.2
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    • pp.38-43
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    • 2024
  • Recently, with the expanding market for electronic devices and electric vehicles, secondary battery usage has been on the rise. Lithium-ion batteries are particularly popular due to their fast charging times and lightweight nature compared to other types of batteries. A secondary battery consists of four components: anode, cathode, electrolyte, and separator. Generally, the positive and negative electrode materials of secondary batteries are composed of an active material, a binder, and a conductive material. Acetylene Black (AB) is utilized to enhance conductivity between active material particles or metal dust collectors, preventing the binder from acting as an insulator. However, when recycling waste batteries that have been subject to high usage, there is a risk of fire and explosion accidents, as accurately identifying the characteristics of Acetylene Black dust proves to be challenging. In this study, the lower explosion limit for Acetylene Black dust with an average particle size of 0.042 ㎛ was determined to be 153.64 mg/L using a Hartmann-type dust explosion device. Notably, the dust did not explode at values below 168 mg, rendering the lower explosion limit calculation unfeasible. Analysis of explosion delay times with varying electrode gaps revealed the shortest delay time at 3 mm, with a noticeable increase in delay times for gaps of 4 mm or greater. The findings offer fundamental data for fire and explosion prevention measures in Acetylene Black waste recycling processes via a predictive model for lower explosion limits and ignition delay time.

Remaining Useful Life Prediction of Li-Ion Battery Based on Charge Voltage Characteristics (충전 전압 특성을 이용한 리튬 이온 배터리의 잔존 수명 예측)

  • Sim, Seong Heum;Gang, Jin Hyuk;An, Dawn;Kim, Sun Il;Kim, Jin Young;Choi, Joo Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.4
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    • pp.313-322
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    • 2013
  • Batteries, which are being used as energy sources in various applications, tend to degrade, and their capacity declines with repeated charging and discharging cycles. A battery is considered to fail when it reaches 80% of its initial capacity. To predict this, prognosis techniques are attracting attention in recent years in the battery community. In this study, a method is proposed for estimating the battery health and predicting its remaining useful life (RUL) based on the slope of the charge voltage curve. During this process, a Bayesian framework is employed to manage various uncertainties, and a Particle Filter (PF) algorithm is applied to estimate the degradation of the model parameters and to predict the RUL in the form of a probability distribution. Two sets of test data-one from the NASA Ames Research Center and another from our own experiment-for an Li-ion battery are used for illustrating this technique. As a result of the study, it is concluded that the slope can be a good indicator of the battery health and PF is a useful tool for the reliable prediction of RUL.

The study on collection efficiency of two-stage electrostatic precipitator using non-metallic electrode for improve corrosion resistance and light weight (내부식성과 경량성 향상을 위한 비금속 재질 집진판의 2단 전기집진기 집진효율 연구)

  • An, So-Hee;Lee, Yeawan;Kim, Ye-Sle;Kim, Yong-Jin;Han, Bangwoo;Kim, Hak-Joon
    • 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 PM2.5 and PM10. As a result of the experiment, two-stage ESP had 22~25% higher collection efficiency in PM2.5 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.

Dependence of Thermal and Electrochemical Properties of ceramic Coated Separators on the Ceramic Particle Size (알루미나 크기에 따른 세라믹 코팅 분리막의 열적 특성 및 전기화학적 특성)

  • Park, Sun Min;Yu, Ho Jun;Kim, Kwang Hyun;Kang, Yun Chan;Cho, Won Il
    • Journal of the Korean Electrochemical Society
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    • v.20 no.2
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    • pp.27-33
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    • 2017
  • Conventional lithium ion batteries suffer from notorious safety issues caused by inevitable lithium dendrite formation and proliferation during over/fast charging processes. The lithium dendrites or mechanical damage on the separator induce internal short circuit in LiB that generates extensive amount of heat within contacted electrode surfaces through the separator. During this heat generation, conventional polyolefin separators shrinks dramatically, and increasing short circuit pathway, that causes the battery to explode. To overcome this serious issue, ceramic coated separators are developed in commercial LiB to enhance thermal and mechanical stability. In this paper, various size(IL = 488.5 nm, I = 538.7 nm, S = 810.3 nm, D = 1533.3 nm) of $Al_2O_3$ particles are coated using styrene-butadiene rubber(SBR) / carboxymethyl cellulose(CMC) binder on PE separator to investigate its thermal stability and electrochemical effect on LiB coin cell with NCM cathode and Li metal anode.

Analysis of the Effect of Superplasticizer combined CASB on Ultra High Strength Mortar and Concrete Using Mineral Admixture (광물질 혼화재 사용 초고강도 모르타르 및 콘크리트에 CASB 화합 고성능감수제의 효과분석)

  • Han, Cheon-Goo;Yoo, Seung-Yeup
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.1
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    • pp.72-79
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    • 2011
  • This study is performed to analyze the effects of CASB by applying the superplasticizer combined CASB on the ultra high strength mortar and concrete that uses different mineral admixture depending on whether the silica fume was used and the results are summarized below. From the characteristics of Fresh mortar and concrete, the fluidity was lower in B2-CASB than B2-PC from the mixing of CASB and based on the viscosity of the mortar and concrete in the binary proportion but in the ternary proportion, B3-CASB showed a larger fluidity than B3-PC because of a reduction in the restriction level due to the effects of an improvement of particle size distribution. The compression strength was higher in ternary proportion than in binary proportion and higher in CASB than in PC from the characteristics of hardening mortar and concrete and this is analyzed as a result of increased minuteness from the calcium silicate hydrates produced from the pozzolan reaction of a mineral admixture, SF, and also the charging effects of capillary pore of CASB. Overall, when using the nanomaterial, CASB in combination with a superplasticizer, the fluidity and the strength aspects of the ternary proportion of ultra high strength mortar and concrete with silica fume may be improved to a higher quality.

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Study on Ti-doped LiNi0.6Co0.2Mn0.2O2 Cathode Materials for High Stability Lithium Ion Batteries (고안정성 리튬이온전지 양극활물질용 Ti 치환형 LiNi0.6Co0.2Mn0.2O2 연구)

  • Jeon, Young Hee;Lim, Soo A
    • Journal of the Korean Electrochemical Society
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    • v.24 no.4
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    • pp.120-132
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    • 2021
  • Although the development of high-Nickel is being actively carried out to solve the capacity limitation and the high price of raw cobalt due to the limitation of high voltage use of the existing LiCoO2, the deterioration of the battery characteristics due to the decrease in structural stability and increase of the Ni content. It is an important cause of delaying commercialization. Therefore, in order to increase the high stability of the Ni-rich ternary cathod material LiNi0.6Co0.2Mn0.2O2, precursor Ni0.6Co0.2Mn0.2-x(OH)2/xTiO2 was prepared using a nanosized TiO2 suspension type source for uniform Ti substitution in the precursor. It was mixed with Li2CO3, and after heating, the cathode active material LiNi0.6Co0.2Mn0.2-xTixO2 was synthesized, and the physical properties according to the Ti content were compared. Through FE-SEM and EDS mapping analysis, it was confirmed that a positive electrode active material having a uniform particle size was prepared through Ti-substituted spherical precursor and Particle Size Analyzer and internal density and strength were increased, XRD structure analysis and ICP-MS quantitative analysis confirmed that the capacity was effectively maintained even when the Ti-substituted positive electrode active material was manufactured and charging and discharging were continued at high temperature and high voltage.