• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2164-2171
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• 2018

Heavy duty diesel vehicles deteriorate urban air quality by discharging a large volume of air pollutants such as soot and nitrogen oxides. In this study, a newly introduced auxiliary device a fuel activation device (FAD) to improve the combustion efficiency of internal engines by utilizing the cavitation effect was closely investigated by the fluid flow mechanism via a numerical analysis method. As a result, the FAD contributed to fuel atomization from the injection nozzle at lower inlet pressure by reducing the pressure energy. The improved cavitation effect facilitated fuel atomization, and ultimately reduced pollutant emission due to the decrease in fuel consumption. The axial velocity along the flow channel was increased 8.7 times with the aid of FAD, which improved the primary break-up of bubbles. The FAD cavitation effect produced 1.09-times larger turbulent bubbles under the same pressure and fuel injection amount than without FAD.

• Smart Structures and Systems
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• v.30 no.6
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• pp.649-659
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• 2022

Structural Health Monitoring (SHM) researchers have identified Augmented Reality (AR) as a new technology that can assist inspections. Post-seismic structural inspections are conducted to evaluate the safety level of the damaged structures. Quantification of nearby structural changes over short-term and long-term periods can provide building inspectors with information to improve their safety. This paper proposes a Time Machine Measure (TMM) application based on an Augmented Reality (AR) Head-Mounted-Device (HMD) platform. The primary function of TMM is to restore the saved meshes of a past environment and overlay them onto the real environment so that inspectors can intuitively measure dynamic structural deformation and other environmental movements. The proposed TMM application was verified by demo experiments simulating a real inspection environment.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.12 no.2
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• pp.71-80
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• 1983

The passive type solar energy heating system for the classroom was investigated. A classroom in a primary school located at Gangnam-ku, Seoul was taken as a model classroom the heat balance equation was established. The temperature in the classroom and solarium were calculated from the heat balance. at clear days, the temperature in the classroom and solarium were measured and compared with the calculated values. The calculated and measured values for the temperature agreed with, in general, in the increasing of $20\%$ range. It was found that the smaller size of solarium could Provide the increasing of energy efficiency for the classroom temperature.

• Journal of the Korean institute of surface engineering
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• v.27 no.3
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• pp.123-133
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• 1994

Oxidation behavior of STS 304 and 430, produced by POSCO, Korea, was studied in order to study the surface defects formed during manufacturing processes. Oxidation experiments were carried out in a preheat-ed furnace at 850~$1, 250^{\circ}C$ in air and in a simulated coke oven gas(COG) atmosphere. The reaction products were examined by XRD, SEM and EDX on their surfaces and cross sections. Protective $Cr_2O_3$-primary oxide film was formed initially, but at critical point this film was broken and a duplex scale consisting of $Fe_2O_3$- and Fe$Cr_2O_4$- was formed. It was more severely attacked in a simulated COG atmosphere than in air, and STS 304 was superior to STS 430 in oxidation resistance.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.06b
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• pp.185-194
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• 1999

This paper suggests the new techmology to control metal flow in order to reduce the number of preforming and machining for the cold forged product with complex geometry. This technology can be summarized the complex forming, which consists of bulk forming and sheet forming, and multi-action forging, which be preformed double action dies. To analyze the process, finite element simulation has been performed. The proposed technology is applied to hub which is part of air conditioner clutch. According to the result of this study, the relative velocity of mandrel and punch is primary process variable.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.173-174
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• 2008

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.69-70
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• 2002

Arsenic (As) is a ubiquitous element found in several forms in foods and environmental media, such as soil, air, and water. The primary route of human exposure is through ingestion of arsenic-contaminated food and drinking water. The predominant form of arsenic in drinking water is inorganic arsenic, which is both highly toxic and readily bioavailable.(omitted)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.395-396
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• 2001

고온의 산업공정에서 발생하는 에어로졸 입자들은 많은 기본입자(primary particle)들로 이루어진 불규칙한 사슬구조를 가진다 (Matsoukas and Friedlander, 1991). 이러한 비구형 프랙탈 입자들의 거동은 구형 입자들과 비교할 때 큰 차이를 보인다. 프랙탈 입자들의 부피는 충돌반경의 거듭제곱으로 나타낼 수 있으며, 프랙탈 차원이라 불리는 그 지수는 1에서 3 사이의 값을 가진다. 자유분자영역에서의 브라운 응집에 대한 해석해는 Lee et al.(1990)에 의해 제시된 바 있으나, 이는 구형입자를 가정한 결과였고, 비구형 프랙탈 입자의 거동을 해석하려 할 때는 이로 인한 오차가 발생하게 된다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.229-230
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• 2002

Diesel exhaust particles are mostly sub-micrometer agglomerates composed of carbonaceous primary particles ranging from 10 to 80nm, but contain also adsorbed or condensed hydrocarbons, hydrocarbon derivatives, sulfur compounds, and other materials. If particles are primarily composed of volatile materials, they have different health impacts from solid particles. Thus, the analysis of the volatility of diesel particles is one of an important diesel research area. (omitted)

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.4
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• pp.201-208
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• 2007

Polychlorinated biphenyls (PCBs) are anthropogenic contaminants found globally in water, ice, soil, air and sediment. Modern analytical techniques allow us to determine these chemicals in environmental matrices at parts per trillion levels or lower. Environmental forensic on PCBs opens up new avenues of investigation such as transport and fate of water masses in oceans, sedimentation, onset of primary production, migration of marine mammals, their population distribution and pharmacokinetics of drugs inside organisms. By virtue of persistence, bioaccumulation, bioconcentration and structure-activity relationship PCBs emerge as unconventional chemical tracers of new sort.