Development of a Real-time Monitoring Device for Measuring Particulate Matter

Kim, Dae Seong,Cho, Young Kuk,Yoon, Young Hun Korean Association for Particle and Aerosol Resear 2014 Particle and Aerosol Research Vol.10 No.1

In this study, we have developed a real-time monitoring device for measuring $PM_{10/2.5/1}$ of ambient aerosol particles. The real-time PM (Particulate Matter) monitor was based on the light scattering method and had 16 channels in particle size. The laboratory and field tests were carried out to evaluate the performance of the PM monitor developed. Arizona Road Dust particles ranging from diameter of 0.1 to $20{\mu}m$ were generated as test particles in the laboratory test. The field test was carried out at the Seoul Meteorological Observatory. We can obtain the particle size and number concentration (particle size distribution) only from the real-time PM monitor developed. Therefore, the average density of aerosol particles was used to obtain the PM data from the particle size distribution. The $PM_{10/2.5/1}$ results of the PM monitor were compared with the data of the Grimm Dust Monitor (Model 1.108) and a beta ray gauge (Thermo Fisher Scientific). As a result, it was shown that the $PM_{10/2.5/1}$ results obtained by the real-time PM monitor agreed well with the data of the reference devices, and overall, the real-time PM monitor could be used as a PM monitoring device for real-time monitoring of the ambient particles.

Development of point-of-use filter evaluation method using chemical mechanical planarization slurry

장선재,아툴 쿨르카르니,김형우,김태성,Jang, Sunjae,Kulkarni, Atul,Kim, Hyeong-U,Kim, Taesung Korean Association for Particle and Aerosol Resear 2016 Particle and Aerosol Research Vol.12 No.4

During the chemical mechanical planarization (CMP) process, slurry that comprises abrasive particles can directly affect the CMP performance and quality. Mainly, the large particles in the slurry can generate the defects on the wafer. Thus, many kinds of filters have been used in the CMP process to remove unwanted over-sized particles. Among these filters, the point-of-use (POU) filter is used just before the slurry is supplied onto the CMP pad. In the CMP research field, analysis of the POU filter has been relatively exceptional, and previous studies have not focused on the standardized filtration efficiency (FE) or filter performance. Furthermore, conventional evaluation methods of filter performance are not appropriate for POU filters, as the POU filter is not a membrane type, but is instead a depth type roll filter. In order to accurately evaluate the POU filter, slurry FE according to particle size was measured in this study. Additionally, a CMP experiment was conducted with filtered slurry to demonstrate the effects of filtered slurry on CMP performance. Depending on the flow rate and the filter retention size, the FE according to particle size was different. When the small and large particles have different FEs, the total filtration efficiency (TFE) can still have a similar value. For this reason, there is a need to measure the FE with respect to the particle size to verify the effects of the POU filter on the CMP process.

Flame Synthesis of Silica-Coated Iron Oxide Nanoparticles and Their Characterization

Jun, Kimin,Yang, Sangsun,Lee, Jeonghoon,Pikhitsa, Peter V.,Choi, Mansoo Korean Association for Particle and Aerosol Resear 2013 Particle and Aerosol Research Vol.9 No.4

We have used the modified diffusion flame burner to synthesize silica coated iron oxide nanoparticles having enhanced superparamagnetic property. Silica-encapsulated iron oxide particles were directly observed using a high resolution transmission electron microscope. From the energy dispersive X-ray spectroscopy (EDS) and zeta potential measurements, the iron oxide particles were found to be completely covered by a silica coating layer. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements revealed that the iron oxide core consists of ${\gamma}-Fe_2O_3$ rather than ${\alpha}-Fe_2O_3$. Our magnetization measurements support this conclusion. Biocompatibility test of the silica-coated iron oxide nanoparticles is also conducted using the protein adsorption onto the coated particle.

The Correlation between Radon (Rn²²²) and Particulate Matters (PM₁₀, PM_2.5, PM_1.0) in Subway Tunnel in Seoul.

Versoza, Michael,Park, Duckshin Korean Association for Particle and Aerosol Resear 2017 Particle and Aerosol Research Vol.13 No.2

Radon ($Rn^{222}$) is a radioactive gas and is found at high concentrations underground. Investigations were done in many years specifically on public transportations such as in the subway stations, concourses and platforms for these are located underground areas. This study correlates the $Rn^{222}$ concentrations with the Particulate Matter (PM) concentration for the gas could be attached or trapped inside these particles. It was done on the opening subway tunnel of Miasageori Station going to Mia Station (Line 4) last August 2016. Based on the result, the $Rn^{222}$ were more influenced on the mass ratio (%) of PM present in the air instead of its mass concentration (${\mu}g/m^3$). As the $PM_{10}$ mass ratio increases ($42.32{\pm}1.03%$) during morning rush-hours, radon starts to increase up to $0.97{\pm}0.03pCi/L$. But during the afternoon $Rn^{222}$ concentrations decreased while the composition were stable at $22.96{\pm}3.0%$, $39.04{\pm}0.6%$ and $38.01{\pm}0.3%$ in $PM_1$, $PM_{2.5}$ and $PM_{10}$ respectively. It was then assumed that it could be the composition of the morning hours of the station were influencing the concentration of the radon.

Development of Light Transmission Fluctuation for Particle Measurement in Solid-Gas Two Phase Flows

YANG, Bin,WANG, Zhan-ping,HE, Yuan,CAI, Xiao-Shu Korean Association for Particle and Aerosol Resear 2016 Particle and Aerosol Research Vol.12 No.1

In order to realize In-line and convenient measurement for solid-gas two phase flows, Light Transmission Fluctuation (LTF) based on the random variation of transmitted light intensity, light scattering theory and cross-correlation method was presented for online measurement of particle size, concentration and velocity. The statistical relationship among transmitted light intensity, particle size and particle number in measurement zone was described by Beer-Lambert Law. Accordingly, the particle size and concentration were determined from the fluctuation signal of transmitted light intensity. Simultaneously, the particle velocity was calculated by cross-correlation analysis of two neighboring light beams. By considering the influence of concentration variation in industrial applications, the improved algorithm based on spectral analysis of transmitted light intensity was proposed to improve measurement accuracy and stability. Therefore, the online measurement system based on LTF was developed and applied to measure pulverized coal in power station and raw material in cement plant. The particle size, concentration and velocity of powder were monitored in real-time. It can provide important references for optimal control, energy saving and emission reduction of energy-intensive industries.

Numerical study of particle dispersion from a power plant chimney

심정보,유동현,Shim, Jeongbo,You, Donghyun Korean Association for Particle and Aerosol Resear 2017 Particle and Aerosol Research Vol.13 No.4

An Eulerian-Lagrangin approach is used to compute particle dispersion from a power plant chimney. For air flow, three-dimensional incompressible filtered Navier-Stokes equations are solved with a subgrid-scale model by integrating the Newton's equation, while the dispersed phase is solved in a Lagrangian framework. The velocity ratios between crossflow and a jet of 0.455 and 0.727 are considered. Flow fields and particle distribution of both cases are evaluated and compared. When the velocity ratio is 0.455, it demonstrates a Kelvin-Helmholtz vortex structure above the chimney caused by the interaction between crossflow and a jet, whereas the other case shows flow structures at the top of the chimney collapsed by fast crossflow. Also, complex wake structures cause different particle distributions behind the chimney. The case with the velocity ratio of 0.727 demonstrates strong particle concentration at the vortical region, whereas the case with the velocity ratio of 0.455 shows more dispersive particle distribution. The simulation result shows similar tendency to the experimental result.

A new description of the fractal dimension of particle aggregates in liquid medium

Xing, Jun,Ding, Shiqiang,Liu, Zhengning,Xu, Jirun Korean Association for Particle and Aerosol Resear 2015 Particle and Aerosol Research Vol.11 No.4

The possible existence forms of particle aggregates in liquid medium are classified into four different types according to their morphological characteristics, including the single particles that are separated from each other, the linear aggregates in which all component particles are located in a line, the planar aggregates where all particles are arranged on a plane, and the volumetric aggregates where all particles forms a three-dimensional space. These particle aggregates with different space morphologies have different fractal dimensions and different influence on the rheological phenomena of the solid-liquid system. The effects of various aggregates on the suspension viscosity are analyzed and related with the particle concentration, and then a mathematical model is presented to determine the fractal dimensions of various aggregates by measuring the apparent viscosity of the solid-liquid system. In the model, the viscous fractal dimension is developed as a new concept, the fractal dimensions of different aggregates can be obtained separately and then the relative components of various aggregates experimentally analyzed.

Removal of Aqueous Cr(VI) using Magnetite Nanoparticles Synthesized from a Low Grade Iron Ore

Do, Thi May,Suh, Yong Jae Korean Association for Particle and Aerosol Resear 2013 Particle and Aerosol Research Vol.9 No.4

We demonstrated the efficacy of magnetic nanoparticles (MNPs) produced from a low grade iron ore as an adsorbent for the removal of Cr(VI), a toxic heavy metal anion present in wastewater. The adsorption of Cr(VI) by these MNPs strongly depended on the dosage of MNPs, the initial concentration of the Cr(VI) solutions, and pH. The highest Cr(VI) adsorption efficiency of 22.0 mg/g was observed at pH 2.5. The adsorption data were best fit with the Langmuir isotherm and corresponded to a pseudo-second-order kinetic model. The used adsorbent was regenerated by eluting in highly alkaline solutions. Sodium bicarbonate showed the highest desorption efficiency of 83.1% among various eluents including NaOH, $Na_2HPO_4$, and $Na_2CO_3$. Due to the high adsorption capacity, the simple magnetic separation, and the high desorption efficiency, this nano-adsorbent produced from inexpensive and abundant resources may attract the attention of the industries to apply for removing various metal anionic contaminants from wastewater.

Oscillatory Reaction in a Liquid-Liquid System with Nano-Particle Under Microwave Irradiation

Asakuma, Y.,Takahashi, S.,Saptoro, A.,Maeda, Y.,Araki, N. Korean Association for Particle and Aerosol Resear 2015 Particle and Aerosol Research Vol.11 No.3

A Belousov-Zhabotinsky reaction in a liquid-liquid system under microwave radiation was observed under non-stirring conditions. To control this non-equilibrium reaction, nano-particle, which is active under microwave irradiation, was added to the solution. Color changes of the solution during the oscillatory reaction were found to be influenced by the irradiation power although the droplet temperature was equal to the temperature of surrounding oil. During the irradiation, the period of oscillation became shorter because the reaction rate was faster. It could also be observed that there is possibility to eliminate oscillatory behaviors of the reaction using higher power of microwave. The possibility of controlling non-linear reaction using microwave was shown since microwave can easily travel through oil phase and reach water phase.

Polymerization of Polyethylene Using Bimodal TiCl₄/MgCl₂/SBA-15/MCM-41

Moonyakmoon, Mattanawadee,Klinsrisuk, Sujitra,Poonsawat, Choosak Korean Association for Particle and Aerosol Resear 2015 Particle and Aerosol Research Vol.11 No.3

MCM-41 (Mobil Composition of Matter) and SBA-15 (Santa Barbara Amorphous) were used as a supported catalyst for ethylene polymerization due to their combination of large surface area and wide range of pore size distribution. The morphology of supports was used to control the morphology of the resulting polymer. Different molar ratios of Al/Ti were used for ethylene polymerization at $60^{\circ}C$ under atmospheric pressure. The effect of different mass ratios of MCM-41/SBA-15 and 1-hexene concentration on polymerization activity and polymer properties was investigated. The catalytic activity and the crystallinity reached the highest value at Al/Ti of 480. Upon incorporation of MCM-41 and SBA-15 into $MgCl_2/TiCl_4$ catalyst, the molecular weight and crystallinity of polyethylene were enhanced. The obtained polyethylene showed melting temperature between 130 and $135^{\circ}C$. The polyethylene with replication structure of support and bimodal MWD was expected.