• Clean Technology
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• v.17 no.4
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• pp.379-388
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• 2011

The purpose of this study was to investigate the concentration levels, distribution characteristics and blood concentration of Polycyclic Aromatic Hydrocarbons (PAHs) at ambient air in Industrial Complex Area. The samples were collected at 4 sites in Industrial Complex Area and its vicinities. The result indicated that there was the difference of PAHs concentration as followed local characteristics. The level of average concentration of PAHs in the air in Industrial Complex Area was $14.52{\sim}193.48ng/m^3$. The level of average concentration of six materials with possibility of cancer creation was $1.65{\sim}13.44ng/m^3$. The concentrations of PAHs were generally low, but Jechul-dong is considered an area where consistent monitoring of PAHs is required. In addition, benzo(a)pyrene was detected in every atmospheric sample, however the concentration was not high. The level of concentration of benzo(a)pyrene in the air in the Jechul-dong was $2.89ng/m^3$. But, the concentration of the PAHs in Jechul-dong showed that the Benzo(a)pyrene concentration is above $1ng/m^3$ of air quality standard(EU). The results of the concentration level of PAHs in the blood from 240 persons who were exposed directly were surveyed, it was $1.12{\sim}11.45ng/m^3$ for man and $1.20{\sim}26.89ng/m^3$ for woman. It was indicated that the difference between the genders was very little. The accumulation inside human was anticipated as the PAHs concentration in the blood for the aged was very high. Industrial Complex Area and its vicinities are an area which has been greatly influenced by PAHs and environmental contaminants. It is necessary to control the emission sources of PAHs and to construct an observation system at Industrial Complex Area from now on. It is time to reduce the risk factors for health and environmental disease to protect the health of resident in Industrial Complex Area and its vicinities.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.397-402
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• 2005

Photovoltaic (PV) module can generate electricity using sunlight without causing any environmental degradation. Due to higher fossil fuel prices and environmental awareness, PV applications are becoming more popular as clean source of electricity generation. PV output is sensitive to the operating temperature and can be drastically affected in Building Integrated PV (BIPV) systems. PV Solarwall (SWPV) combination and PV systems have been evaluated in this study for improvement in electrical output and system costs. PV modules under forced ventilation. A 75W polycrystalline silicon PV module was fixed on SW in front of the ventilation fan as it was indicated to be the coolest position on the SW in phoenix simulations. The effectiveness of cooling by means of the forced ventilating air stream has been studied experimentally. The results indicate that there appears to be significant difference in temperature as well as electricity output comparing the SWPV and BIPV options. Electrical output power recovered is about $4\%$ during the typical day of the month of February. RETScreen(R) analysis of a 3kW PV system hypothetically located at Taegu has shown that with typical temperature reduction of $15^{{\circ}C$, it is possible to reduce the simple payback periods by one year. The work described in this paper may be viewed as an appraisal of a SWPV system based on its improved electrical and financial performances due to its ability to operate at relatively lower temperatures.

• Journal of Energy Engineering
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• v.5 no.1
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• pp.8-18
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• 1996

As a part of comprehensive IGCC process simulation, the thermal performance analysis was performed for coal gas firing combined power plant. The combined cycle analyzed consisted of il Texaco gasifier and a low temperature gas cleanup system for the gasification block and a GE 7FA gas turbine, a HRSG and steam turbine for the power block. A steady state simulator called ASPEN(Advanced System for Process Engineering) code was used to simulate IGCC processes. Composed IGCC configuration included air integration between ASU and gas turbine and steam integration between gasifier, gas clean up and steam turbine. The results showed 20% increase in terms of gas turbine power output(MWe) comparing with natural gas case based on same heat input. The results were compared with other study results which Bechtel Canada Inc. performed for Nova Scotia power plant in 1991 and the consistency was identified within two studies. As a result, the analysing method used in this study is verified as a sound tool for commercial IGCC process evaluation.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.2
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• pp.102-106
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• 2016

An experimental study on the flow characteristics under various laminar coflow diffusion flames was conducted with a particular focus on the buoyancy force exerted from gaseous hydrocarbon fuels. Methane ($CH_4$), ethylene ($C_2H_4$), and n-butane ($C_4H_{10}$) were used as the fuels. A coflow burner and the Schlieren imaging technique were used to observe the flow field of each fuel near the nozzle exit as well as the flow characteristics in the flames. The results show that a vortex with a density heavier than air appeared in n-butane near the nozzle exit with a strong negative buoyancy on the fuel steam. As the Reynolds number increased through the control of the fuel velocity of the n-butane flame, the vortices were greater and the vortex tips were moved up from the nozzle exit. In addition, the heated nozzle affected the flow fields of the fuel steam near the nozzle exit.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.455-459
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• 2013

The fuel processor for the portable fuel cell includes multi-step processes consisting of hydrogen generator, heat generator and several CO clean-up stages. One of requirements of the fuel processor for portable fuel cell system is a rapid start-up time. Especially, the warm-up time for WGS reactor is crucial factors for total start-up time. In this paper, active heating protocol, which is the heating protocol of WGS reactor supplied by the oxidation of CO rich reformate in the initial stage, is used for a rapid start-up. The air stream fed to the inlet of WGS reactor rapidly oxidize the CO rich reformate in the WGS reactor. Therefore, CO concentration in reformate quickly stabilized at the desired concentration without CO surges.

• Journal of Hydrogen and New Energy
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• v.23 no.5
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• pp.503-512
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• 2012

There is a new power generation system such as direct coal fuel cell (DCFC) with a solid oxide electrolyte operated at relatively high temperature. In the system, it is of great importance to feed coal continuously into anodic electrode surface for its better contact, otherwise it would reduce electrochemical conversion of coal. For that purpose, it is required to improve the electrochemical conversion efficiency by using either rigorous mixing condition such as fluidized bed condition or just by recirculating coal particle itself successively into the reaction zone of the system. In this preliminary study, we followed the second approach to investigate how significantly particle recycle would affect the coal conversion efficiency. As a first phase, coal conversion was analyzed and evaluated from the thermochemical reaction of carbon with air under particle recirculating condition. The coal conversion efficiency was obtained from raw data measured by two different techniques. Effects of temperature and fuel properties on the coal conversion are specifically examined from the thermochemical reaction.

• Clean Technology
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• v.25 no.1
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• pp.19-32
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• 2019

As regional air pollution gets worse by the sulfur oxides emitted from various types of vessels passing through the many countries, the International Maritime Organization establishes the emission control areas and regulates sulfur dioxide in those areas. In order to satisfy these regional regulations, the fuel selection method and the exhaust gas post-treatment device are applied to the ships. Due to the economic reasons, the post-treatment method of exhaust gas for reducing the amount of sulfur oxides discharged is mainly preferred. The scrubber which is dominantly used in the ships are the spray type system where the sprayed liquid drops used for capturing the soluble sulfur dioxides in the exhaust gas. The performance of the spray type system depends on the size distribution of the sprayed droplets. In order to evaluate this performance, we designed counterflow type scrubber and cyclone scrubber and evaluated the desulfurization efficiency and the amount of droplet evaporation according to the size of each droplet by using computational fluid dynamics. The Eulerian-Eulerian analysis method was used because the scrubber had a gas-liquid two-phase flow inside the scrubber. When the diameter of the droplet was $100{\mu}m$, $300{\mu}m$, $500{\mu}m$ and $700{\mu}m$. As a result, both of scrubbers showed high desulfurization efficiency and low evaporation amount at $500{\mu}m$ and $700{\mu}m$.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.177-188
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• 2019

The purpose of the optimization of the installation of supply/exhaust ports for tunnels with transverse ventilation system is to supply fresh air from outside to inside of tunnels uniformly and exhaust pollutant from tunnels properly for creating safe and clean environment for tunnel users. For this purpose, a ventilation port area optimization program was developed to obtain a uniform supply or exhaust air volume inside a great depth double deck tunnel with transverse ventilation system. In order to area optimize the developed port sizing program, the wind velocity was measured in the duct of the currently operated tunnel with semi-transverse ventilation. Also 3D cfd was performed on the same tunnel and cfd results were compared to the measured value. As a result, the error rate between the predicted value from the program and measured value was 6.72%, while the error rate between the predicted value from the program and 3D cfd analysis value was 4.86%. Both of comparison results show less than 10% of error rate. Thus It is expected that supply/exhaust port optimization design of transverse ventilation tunnel can be possible with using this large exhaust port area optimization program.

• Korean Journal of Human Ecology
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• v.19 no.1
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• pp.215-225
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• 2010

This study had the purpose of presenting a residential environment solution as a desirable educational environment for middle school students to grow soundly and to achieve proper self-realization while providing basic materials to build up a suitable residential environment by comparing and analyzing what relationships exist between different home backgrounds, residential environments and middle school students' social maturity. This research was conducted from Feb. 11, 2008 to Feb. 13, 2008. The subject of this research was 601 students in 3 middle schools located in Gyunggi-do. The data analyzed used the SPSS 11.5 version. The summary of this study's results is as follows. First, in terms of home background, the higher the parents' educational background and social and economic position, the greater the students' social maturity. Second, in terms of home environment, the more spacious the living space, the better the water and sewage system and rest room, the more convenient the air conditioner and kitchen system, the better the lighting, ventilation, soundproofness, insulation, the less the danger in relation to fire, crime, traffic accidents, disaster, the greater the students' social maturity. Third, in terms of the home environment related to the correlation between the residential environment and social maturity, all areas such as housing facilities, housing structural environment and housing safety showed static correlations and proved that the residential environment has an important influence on social maturity. Accordingly, in order to build up an ideal residential environment, we should make efforts to expand and improve better facilities at home considering privacy, lighting, ventilation, soundproofness, heating etc. and remove unsound factors that obstruct students social maturity and build up clean and safe residential environment with good relations with their neighbors.

• Textile Coloration and Finishing
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• v.22 no.2
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• pp.173-179
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• 2010

In this study, we determine the stretch and shrinkage properties of conjugated yarns. The shrinkage(%) and elasticity(%) were determined by applying twist conditions of 0, 350, 800, 1000, 1200, 1400, 1600, 2000 T/M (twisting per meter). It is found that the shrinkage(%) and elasticity(%) gradually decreased with increasing T/M. Especially the elasticity(%) dramatically decreased over 1400 T/M condition. In contrast, it is showed that the handle and drapery properties decreased below 1000 T/M, which indicates that the optimal T/M condition could be 1000~1400. The effect of shrinkage(%) and elasticity(%) with different steam setting temperatures (60, 70, 80 and $90^{\circ}C$) was also determined. The shrinkage(%) decreased with increasing setting temperature, while the elasticity not changed. In this context, the optimal steam setting temperature could be $80^{\circ}C$ because it is not easy to weave with the yarns which was set below $80^{\circ}C$. The elasticity(%) decreased with increasing the density of warp and weft. To produce soft handle, excellent drapery and good stretch fabrics, the warp density needs to be reached by 90% of the ideal warp density. In the case of NaOH treatments to the fabrics, the elasticity(%) increased with increasing weight reduction. Therefore, this study have demonstrated that the conjugated yarns with core yarn and the SDY CD(cation dyeable spindraw yarn) as an effect yarn would be appropriate to produce excellent mixture-yarn, which displays clean appearance, good handle and excellent elasticity, The optimized conditions are as follows; 1000~1200 twist per meter, $80^{\circ}C$ steam setting temperature, 90% of ideal warp density and relaxation condition treated with 5g/l NaOH concentration.