• Journal of Energy Engineering
• /
• v.13 no.2
• /
• pp.118-127
• /
• 2004

The purpose of this study is experimentally to analyze that intake port swirl, injection system and turbocharger have an effect on the engine performance and the emission characteristics in a V8 type turbocharged intercooler D.I. diesel engine of the displacement 16.7ι, and to suggest the improvement of engine performance. Generally to enhance engine power, TCI diesel engine is put to practically use turbo-charged intercoler in order to increase boost efficiency which is cooled boost air. As results of considering the factors of the intake port of swirl ratio 2.25, compression ratio 17.5, re-entrant 8.5$^{\circ}$ combustion bowl, nozzle hole diameter ${\Phi}$0.33*3+${\Phi}$0.35*2, nozzle protrusion 3.18mm, injection timing BTDC 12$^{\circ}$CA and turbo charger (compressor 0.6A/R+46Trim, turbine 1.0A/R+57Trim) is the best in the full range of operating in the engine performance and the exhaust characteristics of NO$\_$x/ concentration. Therefore their factors are appropriated as intake system, injection and turbocharger system.

• Asian Journal of Atmospheric Environment
• /
• v.5 no.2
• /
• pp.134-143
• /
• 2011

The present study aimed to investigate the diurnal variations in air concentrations and exchange fluxes of ammoniacal nitrogen ($NH_x$: ammonia ($NH_3$) and particulate ammonium) in a subalpine deciduous forest in central Japan during a week in summer. The $NH_3$ concentrations ($0.50\;{\mu}g\;N\;m^{-3}$ on average) showed a clear circadian variation, i.e., high and low in the daytime and nighttime, respectively. The concentration of particulate ammonium in the coarse fractions was extremely low, whereas that for the PM2.5 fraction was relatively high $0.55\;{\mu}g\;N\;m^{-3}$ on average). The main inorganic ion components of PM2.5 at the study site were ammonium and sulfate. The exchange fluxes of $NH_x$ were bidirectional. Both the maximum and minimum values occurred in the daytime, i.e., $0.39\;mg\;N\;m^{-2}\;hr^{-1}$ of downward flux and $0.11\;mg\;N\;m^{-2}\;hr^{-1}$ of upward flux for $NH_3$ and $0.25\;mg\;N\;m^{-2}\;hr^{-1}$ of downward flux and $0.13\;mg\;N\;m^{-2}\;hr^{-1}$ of upward flux for PM2.5 ammonium. The exchange fluxes of $NH_x$ at night could be considered as zero. The mean deposition velocity during the research period was almost zero for both $NH_3$ and PM2.5 ammonium. The atmosphere-forest exchange of $NH_x$ in the forest during the study period was balanced. The remarkably large deposition of $NH_x$ was attributable to meteorological events such as showers the night before that thoroughly washed the forest canopy and subsequent clear skies in the morning, which enhanced convection. The cleaning effect of rainfall and the rapid change in convection in the early morning should be monitored to evaluate and generalize the gas and particle exchange in a forest.

• Journal of environmental and Sanitary engineering
• /
• v.24 no.4
• /
• pp.60-68
• /
• 2009

The most principal approach to improve indoor air quality(IAQ) of subway was to examine the fine particulate(PM-10) from the emission sources. Therefore, this study was carried on the investigation the fine particulate for comparison with the removal efficiency of PM-10 in divided the PSD(Platform Screen Door) and Non-PSD subway station from July, 2007 to May 2008. In the monitoring results, the range of PM-10 concentration of Non-PSD station was $44.6{\sim}116.5{\mu}g/m^3$ and the range of PM-10 concentration of PSD station was $23.9{\sim}81.1{\mu}g/m^3$. And then the range of PM-2.5 concentration of Non-PSD station was $17.4-56.6{\mu}g/m^3$, and then the range of PM-2.5 concentration of PSD station was $17.9{\sim}34.4{\mu}g/m^3$. In comparison with the results of the PSD and Non-PSD subway station, we found that the PM-10 removal efficiency of PSD was 30-40%. In conclusion, the PSD will be applied the effective facilities of decreasing PM-10 in subway station in Korea.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.764-769
• /
• 2001

Recently, according to increase in the requirement of electric power, a thermoelectric power plant equipped with pulverized coal combustion system is highly valued, because coal has abundant deposits and a low price compared with others. For efficient use of coal fuel, most of plant makers are studying to improve combustion performance and flame stability, and reduce pollutant emission. One of these studies is how to control the profile of particle injection and velocity dependant on coal nozzle. Basically, a mixed flow of gas and particle in coal nozzle is required to have appropriate injection and concentration distribution at exit to achieve flame stability and low pollutant, but it is very difficult to obtain that without help of a coal separating device within nozzle. In this study, each distribution of air and coal flow rate is measured for the coal nozzle with coal separator developed by us. The coal concentration at exit is various according to inlet swirl values and positions of coal separator. Also pressure drop is measured for various operating conditions of this nozzle. From these results, we can find the separation characteristic of new developed coal separator, and select proper operation range of coal nozzle. When this coal nozzle is applied to actual plant, these investigations will be very useful to confirm the shape of coal separator to have efficient particle injection.

• Journal of Environmental Science International
• /
• v.25 no.1
• /
• pp.107-125
• /
• 2016

Long-term variations of $PM_{10}$ and the characteristics of local meteorology related to its concentration changes were analyzed at 4 air quality sites (Ido-dong, Yeon-dong, Donghong-dong, and Gosan) in Jeju during two different periods, such as PI (2001-2006) and PII (2007-2013), over a 13-year period. Overall, the long-term trend of $PM_{10}$ was very slightly downward during the whole study period, while the high $PM_{10}$ concentrations in PII were observed more frequently than those in PI. The concentration variations of $PM_{10}$ during the study period was clarified in correlation between $PM_{10}$ and meteorological variables, e.g. the low (high) $PM_{10}$ concentration with large (small) precipitation or high (low) radiation and in part high $PM_{10}$ concentrations (especially, Donghong-dong and Gosan) with strong wind speed and the westerly/northwesterly winds. This was likely to be caused by the transport effect (from the polluted regions of China) rather than the contribution of local emission sources. The $PM_{10}$ concentrations in "Asian dust" and "Haze" weather types were higher, whereas those in "Precipitation", "Fog", and "Thunder and Lighting" weather types were lower. The contribution of long-range transport to the observed $PM_{10}$ levels in the urban center (Ido-dong, Yeon-dong, and Donghong-dong), if estimated by comparison to the data of the background site (Gosan), was found to explain about 80% (on average) of its input.

• Korean Journal of Materials Research
• /
• v.23 no.12
• /
• pp.727-731
• /
• 2013

In this study, green barium strontium silicate phosphor ($BaSrSiO_4:Eu^{3+}$, $Eu^{2+}$) was synthesized using a solid-state reaction method in air and reducing atmosphere. Investigation of the firing temperature indicates that a single phase of $BaSrSiO_4$ is formed when the firing temperature is higher than $1400^{\circ}C$. The effect of firing temperature and doping concentration on luminescent properties are investigated. The light-emitting property was the best when the molar content of $Eu_2O_3$ was 0.025 mol. Also, the luminescent brightness of the $BaSrSiO_4$ fluorescent substance was the best when the particle size of the barium was $0.5{\mu}m$. $BaSrSiO_4$ phosphors exhibit the typical green luminescent properties of $Eu^{3+}$ and $Eu^{2+}$. The characteristics of the synthesized $BaSrSiO_4:Eu^{3+}$, $Eu^{2+}$ phosphor were investigated using X-ray diffraction (XRD) and scanning electron microscopy. The maximum emission band of the $BaSrSiO_4:Eu^{3+}$, $Eu^{2+}$ was 520 nm.

• Land and Housing Review
• /
• v.1 no.1
• /
• pp.113-124
• /
• 2010

This study is evaluating that new hi-tech transit systems each type of function and introduce applicable guideline decreases land sale price in New town and Large scale land development projects. For this, use the look-up table through the composite category of each type of system at the functional types, local characteristics. It also, As introduce the new systems calculate the Social benefits such as altered public traffic transfer system, reduced transit time and reduced carbon emission considering the three-dimensional arterial roads. As a result, New transportation systems contribute that the more reducing traffic congestion and air pollution and municipalities seeks for environment-friendly policy. However, this paper emphasize that the new transportation system has been introduce without considering the characteristics of locality and the efficient arrangement of them, it cannot be transferred the to the existing public traffic efficiently, futhermore causes the sale price in new large scale land development projects.

• Korean Institute of Interior Design Journal
• /
• v.17 no.3
• /
• pp.23-33
• /
• 2008

After the concept of apartments was introduced in 1960s in Korea, on account of the development of architectural technology and science, high-rise residences in Korea are getting higher, and these residences have been becoming high-rise commercial/residential buildings since 1990. Nowadays, as the construction of high-rise commercial residential building complex is booming, the difference between these complex and high-rise apartments is getting smaller, and these two kind of high-rise residences are becoming new residential style in Korea. And these high-rise residences are considered the symbol of wealth owing to the marketing strategy emphasizing high quality, refined interior, a fair view, and the protection of privacy. However, high-rise residences bring about many problems related to health and psychology caused by the consumption of a large amount of energy, pollutant emission, the deterioration of the quality of indoor air, and vibration. For this reason, in this study, we tried to emphasize the necessity of environment-friendly access to provide healthy living environment and to reduce the negative effect of housing life in high-rise residences, and find the method to improve environment-friendly quality and health of residents in interior space. Therefore, this study aims to detect the problems and the items to be improved of interior spaces of high-rise residences by quantitative, qualitative analysis of the evaluation elements and the floor planning elements deduced from environment-friendly architectural certification in Korea and the other countries, and suggest the guideline to improve the environment-friendly quality of these interior spaces.

• Journal of the Korean Institute of Gas
• /
• v.24 no.4
• /
• pp.39-47
• /
• 2020

Flue gas recirculation(FGR) is an effective combustion technique for reducing nitrogen oxides(NOx) and is applied in various fields of low-pollution combustion. Continuing the previous study, a numerical analysis was conducted to identify changes of flame characteristics and NOx formation mechanism with applying FGR technique in CH₄/air premixed counterflow flames. NOx emitted was divided into four main reaction paths(thermal NO, prompt NO, N₂H and N₂O), showing relatively the production rate of NO with the recirculation ratio. As a result, thermal NO contributed greatly to the overall NO whereas the effect of N₂H was minimal. In addition, emission index of NO was compared as the recirculation ratio increased by modifying the UC San Diego mechanism to examine the contribution of thermal NO.

• Tribology and Lubricants
• /
• v.31 no.6
• /
• pp.258-263
• /
• 2015

Biodiesel is an environmentally-friendly fuel with low smoke emission because it contains about 10% oxygen. Biodiesel fuel prepared by transesterification of vegetable oil or animal fats is susceptible to auto-oxidation. The rate of auto-oxidation depends on the number of methylene double bonds contained within the fatty acid methyl or ethyl ester groups. Biodiesel may be easily oxidized under several conditions, i.e., upon exposure to sunlight, temperature, oxygen environment. Maintenance of the fuel quality of biodiesel requires the development of technologies to increase the resistance of biodiesel to oxidation. Treatment with antioxidants is a promising approach for extending the shelf-life or storage time of biodiesel. The chemical properties of various amine-based antioxidants were evaluated after synthesis of the antioxidants by condensation of phenylenediamine with alkylamines at room temperature. In general, the oxidative stability can be assessed based on various experimental parameters. Such parameters may include temperature, pressure, and the flow rate of air through the samples. The Rancimat method (EN14112) was selected because it is a rapid technique that requires very little sample and provides good precision for oxidative degradation analysis. Specifically, the EN 14112 technique provides enhanced efficiency for oxidative stability evaluation when a larger ester head group is utilized. Therefore, this technique was employed for evaluation of the oxidation stability of biodiesel by the Rancimat method (EN14112).