• Journal of ILASS-Korea
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• v.13 no.2
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• pp.65-72
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• 2008

It is recognized that alternative fuel such as dimethyl ether (DME) has better combustion polluting characteristics than diesel fuel, even though the cetane number of DME is almost the same as that of diesel. Characteristics of DME spray were observed experimentally under various ambient conditions using a constant volume chamber and a common-rail injection system. N-dodecane and LPG fuel sprays were also observed under same conditions of DME spray. Using spray images from backlight scattering and Mie scattering, characteristics of fuel sprays such as penetration and spray volume were visualized and quantitatively measured. The measurements showed that the penetration of early period decreased remarkably, because evaporation of alternative fuels became prosperous by the influence of flash boiling phenomenon under the condition of the low temperature and pressure compared with n-dodecane. The penetration of DME and LPG spray received the influence of temperature more largely in comparison with low density, because the specific surface area increased by atomizing in high density.

• Journal of Biosystems Engineering
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• v.21 no.2
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• pp.117-122
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• 1996

Droplet sizes produced from a mist blower should be adequate to get highly biological effects with a reasonable level of work performance. However the droplet sizes from the conventional nozzles of the mist blower were around VMD 95 to 469$\mu$ which were relatively large as compared with the recommended droplet sizes in liquid flow rate of 17.2 m$/ell$s with air flow rate of 16660$m^3$/s on the maximum travel distance of about 4.0 m. The velocity of air stream at the point where two fluids, air and liquid, impact each other, was tried to maximize as much as possible in order to enhance the atomization performance of a newly designed twin fluid nozzles with the same or better level of performance of the conventional mist blower, The configuration of nozzle orifice should be designed to enlarge the contact area between air and liquid to enhance the atomization.

• Journal of Power System Engineering
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• v.8 no.4
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• pp.38-43
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• 2004

Thermal spraying onto the metal substrate has been widely used as a technique of the surface treatment in the various industrial field. A wide range of thermal spray technologies exist and all rely on the fundamental process of fusing a metal feedstock, atomizing it and transporting it to the surface of a substrate. Specially, these methods have been taken into account as the protection method against the corrosion. In this study, the polarization characteristics were carried out on the thermal sprayed coating layer immersed in various pH of diluted aqueous solutions at $25^{\circ}C$. Aluminum, Zinc, Ni-base alloy, alumina and polyethylene powder were used with sprayed coating materials. From the polarization curves, the electrochemical corrosion potential($E_{corr}$) and the corrosion current density($I_{corr}$) were investigated.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.175-178
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• 2011

본 연구에서는 기존의 고압으로 작동되는 고압 미분무 건과는 달리 Twin-Fluid의 Turbulence 및 Break-up 현상 등을 이용하여 저압상태에서 작동하며 경량화 및 소형화에 성공하여 기존 소방관의 진입이 어려운 장소 또는 수원으로부터 멀리 떨어진 곳에서 원활한 소화활동을 위해 개발한 저압용 미분무 건의 성능을 화재소화능력 시험을 통해 입증하였다. 화재 소화능력 시험을 수행한 결과 물과 질소가 Mixing Chmaber 내부에서 혼합되면서 두 유체간의 상호작용 및 운동 에너지으로 인해 물의 액적이 미세하게 Atomizing되어 목재화재는 물론 유류화재의 진압에 있어서도 우수한 성능을 확인할 수 있었다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.36-37
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• 2016

Among all the slags, ladle furnace slag (LFS) is reducing slag generated from electric arc furnace. After cooled rapidly by high-pressured air (atomizing technology), LFS has more amorphous phase than slow cooled slag. Therefore, it shows higher reactivity than another recycling slag. This material also is named by rapid cooling LFS (RC-LFS). Pulverized RC-LFS should be fully understood. This paper deal with the present some basic experimental properties and discussions about the setting time of pulverized RC-LFS with different gypsum under the various temperatures. According to the experimental results, the pulverized RC-LFS with gypsum can hydrate in a low-temperature environment, even though the initial and final setting time are delayed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.5
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• pp.405-410
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• 2009

The conventional ultrasonic nozzle produces a mist by applying an ultrasonic vibration into a non-flowering liquid. In this paper, we first present a novel designed nozzle type sprayer that is able to apply an ultrasonic vibration directly to the moving liquid and generate a mist instantly. For the novel nozzle, a ring-type actuator of the novel nozzle was designed and built using the PZW-PMN-PZT ceramics. This paper will describe a variety of physical, mechanical, and electrical characteristics of the ultrasonic nozzle. The characteristics of the mist particles was also measured as the amount of the outflow liquid was varied.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.169-170
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• 2006

Advanced melting technology is now being employed in the manufacture of stainless steel powders. The new process currently includes electric arc furnace (EAF) technology in concert with Argon Oxygen Decarburization (AOD), High Performance Atomizing (HPA) and hydrogen annealing. The new high performance-processing route has allowed the more consistent production of existing products, and has allowed enhanced properties, such as improved green strength and green density. This paper will review these processing changes along with the potential new products that are being developed utilizing this technology. These include high strength stainless steels such as duplex and dual phase as well as stainless steel powders used in high temperature applications such as diesel filters and fuel cells.

• Fire Science and Engineering
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• v.9 no.2
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• pp.10-16
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• 1995

This study discribes characteristics of water spray for extinguishment of gasoline fire. Experiments are carried out for the gasoline pool fire nth the atomizing nozzles. Droplet size, spray pressure, amount of water which reaches the flame base and velocity of water spray are measured to find extinguishment conditions. Air entrainment due to the water spray and extinguishing process of gasoline fire by water spray are visualized. Boundary conditions of water spray for extinguishment of gasoline pool fire is quantitatively shown. As the result of experiments, it is found that the velocity of entrainment air and sprayed water are almost same and the water droplets size having small diameter under 40$\mu\textrm{m}$ can not extinguish the fire because too small droplets does not reach the fuel surface.

• Journal of the Korean Society for Heat Treatment
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• v.21 no.4
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• pp.205-212
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• 2008

Characteristics of microstructures, mechanical properties and formability of two Al-20Si-5Fe-2Ni alloys produced by gas atomizing (P/M) and spray forming (S/F) respectively were compared at temperatures up to $560^{\circ}C$. Room temperature hardness values and tensile strengths of both alloys were increased in accordance with temperature after heat treatment above $300^{\circ}C$. The highest values of hardness and tensile strength of both alloys were obtained at $490^{\circ}C$. It was interpreted that increase in hardness and tensile strength according to heating temperature between $300{\sim}490^{\circ}C$ was mainly related to increase in internal stress between Al matrix and reprecipitated particles. S/F alloys showed better formability and wear property than P/M alloys due to the homogenity of microstructures above $300^{\circ}C$.

• Korean Journal of Metals and Materials
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• v.46 no.8
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• pp.506-515
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• 2008

Recently, it is exceedingly required to produce metal powders with tailored shape and phase altogether in order to fabricate high performance functional parts such as magnetic core or electro-magnetic noise suppressor for high frequency usage. Therefore, the collision phenomena of in-flight droplets against chamber wall or neighboring in-flight droplets each other is investigated by a computational method in order to get useful information about how to design the atomizing system and how to tailor process parameters not to make irregular-shaped powders during gas atomization process. As a results, smaller powders, lower melt temperature are known to be favorable for droplets not to collide against chamber wall. In additions, powders of narrower size distribution range, lower droplet generation rate, lower melt temperature, lower gas velocity are desirable to prevent droplet-collisions against neighboring in-flight droplets.