• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.3
• /
• pp.82-88
• /
• 2013

In this project a preliminary experimental research work was done to apply mortars containing magnetite as fine aggregates unto floor finishing materials in order to make indoor environment eco-friendly and to have noiseproof control between floors. Crushed magnetites were substituted as sands in the mix design with a range of 0, 20, 40, 60, 100%. First far-infrared radiation tests to determine emissivity and emission power were done in accordance with the KICM test standard and an outstanding result was obtained. Density and compressive strength test results also showed that as the substitution increases, test values increase in a linear trend. However dry shrinkage test results revealed that as the substitution increases, shrinkage strain also increases. To clearly seek a solution about this problem, more experimental works should be done on oncoming experimental program.

• Journal of Environmental Science International
• /
• v.24 no.10
• /
• pp.1273-1283
• /
• 2015

In present study, the temporal characteristics of nine selected volatile organic compounds (VOCs), including four alcohol, 2 aldehyde, and 3 ketone compounds, in high-stories urban apartments over a 2-y period were investigated. The indoor VOC concentrations had generally a decreasing trend over the 2-y follow-up period. For examples, the 2E1H indoor concentration decreased from $10.8{\mu}g/m^3$ for the first two months to $5.1{\mu}g/m^3$ for the last two months. In addition, the DCA and ACT indoor concentrations decreased from 5.0 and $14{\mu}g/m^3$ for the first two months to 2.2 and $6.4{\mu}g/m^3$, respectively, for the last two months. The indoor-to outdoor concentration ratios over the 2-y period were much greater than 1, indicating that indoor VOC concentrations were higher than the outdoor VOC concentrations. Similar to those of the individual VOCs, the indoor-to-outdoor concentration ratios of all three VOC groups were higher than 1 over the 2-y follow-up period, suggesting higher indoor concentrations of the three VOC groups than outdoor concentrations. In consistence with the results of VOC indoor concentrations, the VOC emission rates decreased gradually as time passed, due to the decreased VOC emission strengths of indoor sources. Finally, there was an initial sharp decrease in the indoor VOC concentrations followed by a slower decrease, indicating a multi-exponential decay model for the target VOCs, which was demonstrated by comparison of the residuals and the adjusted coefficient of determination associated with the one and two-exponential fits of each data set.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.142.2-142.2
• /
• 2015

Plasma etch endpoint detection (EPD) of SiO2 and PR layer is demonstrated by plasma impedance monitoring in this work. Plasma etching process is the core process for making fine pattern devices in semiconductor fabrication, and the etching endpoint detection is one of the essential FDC (Fault Detection and Classification) for yield management and mass production. In general, Optical emission spectrocopy (OES) has been used to detect endpoint because OES can be a simple, non-invasive and real-time plasma monitoring tool. In OES, the trend of a few sensitive wavelengths is traced. However, in case of small-open area etch endpoint detection (ex. contact etch), it is at the boundary of the detection limit because of weak signal intensities of reaction reactants and products. Furthemore, the various materials covering the wafer such as photoresist (PR), dielectric materials, and metals make the analysis of OES signals complicated. In this study, full spectra of optical emission signals were collected and the data were analyzed by a data-mining approach, modified K-means cluster analysis. The K-means cluster analysis is modified suitably to analyze a thousand of wavelength variables from OES. This technique can improve the sensitivity of EPD for small area oxide layer etching processes: about 1.0 % oxide area. This technique is expected to be applied to various plasma monitoring applications including fault detections as well as EPD.

• Journal of Environmental Health Sciences
• /
• v.44 no.2
• /
• pp.160-168
• /
• 2018

Objectives: The purposes of the study were to investigate hazardous pollutant emissions changes among group 1 carcinogens. The emissions characteristics were compared with national cancer registration statistics. Methods: A survey of group 1 carcinogen hazardous pollutant emissions (trichloroethylene, benzene, vinyl chloride, formaldehyde, 1,3-butadiene, ethylene oxide, chromium and its compounds, 3,3'-dichloro-4,4-diaminodiphenylmethane, chloromethyl methyl ether, arsenic and its compounds, cadmium and its compounds, o-toluidine) was conducted through a homepage for 2001-2015. The emission of hazardous chemicals and the cancer trend analysis for 2001-2015 were performed using the Korean statistical information service through its homepage as a reference. Results: Emissions of more than 95% of the substances listed as group 1 carcinogens over the last five years were made up of trichloroethylene, benzene, vinyl chloride, formaldehyde, 1,3-butadiene, and ethylene oxide. As a result of the comparison of emission results and cancer incidence rates, carcinogen pollutant emissions showed a tendency to decrease continuously. In addition, the incidence of cancer tended to increase, but showed a tendency to decrease from 2012. Conclusion: The results indicate hazardous pollutant emissions have continued to increase. However, no association between emissions and health effects was shown and more research is needed.

• International Journal of Automotive Technology
• /
• v.8 no.4
• /
• pp.421-428
• /
• 2007

This paper investigates the combustion and emission characteristics of a compression ignition engine fueled with neat and blended Shell's gas-to-liquid (GTL) fuel, which was derived from natural gas through the Fischer-Tropsch process. The experiments were conducted in a 6-cylinder DI diesel engine with pump timing settings of $6^{\circ},\;9^{\circ}\;and\;12^{\circ}$crank angle before TDC over ECE R49 and US 13-mode cycles separately and compared to a conventional diesel fuel. The results show that GTL exhibited almost the same power and torque output, improved fuel economy and effective thermal efficiency. It was found that GTL displayed lower peak in-cylinder combustion pressure and maximum heat release rate (HRR), the timings of the peak pressure and the maximum HRR were generally delayed, and the combustion durations were almost equivalent for diesel and GTL under the same speed-load condition. The results also indicate that, compared to diesel fuel, GTL blends showed a trend forward decreasing four regulated emissions simultaneously and a higher GTL fraction in blends contributing to further reductions in the emissions. In particular and on average, neat GTL significantly reduced HC, CO, NOx and PM by 16.4%, 17.8%, 18.3% and 32.4%, respectively, for all cases.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.5
• /
• pp.757-764
• /
• 2017

As the reduction of greenhouse gases(GHGs) emission has become a global issue, the microgrid markets are growing rapidly. With the sudden changes in the market, Korean government suggested a new business model called 'Self-Sufficient Energy Islands'. Its main concern is a stand-alone microgrid composed of Distributed Energy Resources(DERs) such as Renewable Energy Sources(RESs), Energy Storage System(ESS) and Fuel Cell, in order to minimize the emission of GHGs. According to these trend, this paper is written to propose an optimal sizing method of DERs in a stand-alone microgrid by using Genetic Algorithm(GA), one of the representative stochastic methods. It is to minimize the net present cost with the variables, size of RESs and ESS. In the process for optimization, the sunless days are considered as additional constraints. Through the case study analysis, the size of DERs installed in a microgrid system has been computed using the proposed method in MATLAB. And the result of MATLAB is compared with that of HOMER(Hybrid Optimization of Multiple Energy Resources), a well-known energy modeling software.

• KIEAE Journal
• /
• v.14 no.2
• /
• pp.37-46
• /
• 2014

University buildings are energy-guzzling facility that consume more than 10,000TOE within a campus annually. Even the consumption is on an upswing trend. Behind such high consumption are there cheap power rates for education facility, lack of high-efficiency equipment and ever-increasing use of various information equipment. Being keenly aware that greenhouse gas emission increases due to such rise of energy consumption, the present study carried out a case study. In the case study, the study chose the buildings of E university from top 10 universities that consume energy most in Seoul and examined the current status of their energy consumption and greenhouse gas emission. And then it set the reduction target of greenhouse gas by year. Putting aside a middle and long-termed strategy for later endeavor, it first established the 1st year's implementation plan (2014) for energy saving and greenhouse gas reduction with limited budget and according to greenhouse gas reduction target. The plan is specified as follows. Targets for energy saving are mainly divided into two sectors: machine equipment and electric equipment. 7 ideas were proposed. Three ideas to improve machine equipment are to replace with high-efficiency boilers and chillers and to adjust the position of the cooling tower. By doing so, it was estimated that energy could be saved by 176.34TOE in total and greenhouse gas could be reduced by 370.771t$CO_2$-eq. Four ideas to improve electric equipment include the replacement with LED lights, LED emergency lights and high-efficiency motors and the installation of motion sensors. It was calculated that such replacement could conserve 1,076.08TOE (electric energy) and reduce 2,181.420t$CO_2$-eq (greenhouse gas).

• Journal of ILASS-Korea
• /
• v.20 no.3
• /
• pp.149-155
• /
• 2015

With increasing of GDP, the registration number of passenger cars has exceeded 20 million last year in Korea. Especially, the registration number of the diesel engine vehicles has been increasing. However, the WHO(World Health Organization) IARC (International Agency for Research on Cancer) has reported that diesel engine exhaust gas is an one of HAPs, which has carcinogenic for human, and they have designated it to Group 1. To solve this problem, exhaust gas from diesel engines has to be controlled. Thus, it has been controlling by European regulatory standard in Korea. On the other hand, in order to meet the enhanced emission regulations, all manufacturing company applied $NO_x$ control device to vehicles such as EGR (Exhaust Gas Recirculation), SCR (Selective Catalytic Reduction) and so on. However, these devices (EGR, SCR) were operated by difference reaction mechanism respectively, and the composition of exhaust gas would be differenced from that of them. In this study, it was conducted to evaluate variety characteristics on changing of exhaust gas composition by each $NO_x$ control device, and the heavy duty diesel trucks were chosen as experimental vehicles. From the result, it revealed that vehicles (with EGR) were discharged higher THC as 52.5% than that of others (with SCR). However, it did not followed that trend, in the case of CO; it was discharged as 57.2% lower than that of others (with SCR). In the future, these data would be used to apply to efficient $NO_x$ control device for meeting to EURO 6.

• The Bulletin of The Korean Astronomical Society
• /
• v.41 no.1
• /
• pp.35.2-35.2
• /
• 2016

We present a census of AGN-driven gas outflows based on the kinematics of ionized gas and stars, using a large sample of ~11,000 emission line galaxies at z < 0.3, selected from SDSS. First, a broad correlation between gas and stellar velocity dispersions indicates that the bulge gravitational potential plays a main role in determining the ionized gas kinematics. However, the velocity dispersion of the [OIII] emission line is larger than stellar velocity dispersion by a factor of 1.3-1.4, suggesting that the non-gravitational (non-virial) component, i.e., outflows, is almost comparable to the gravitational component. Second, gas-to-stellar velocity dispersion ratio increases with both AGN luminosity and Eddington ratio, suggesting that non-gravitational kinematics are clearly linked to AGN accretion. The distribution in the [OIII] velocity - velocity dispersion diagram dramatically expands toward large values with increasing AGN luminosity, implying that the launching velocity of gas outflows increases with AGN luminosity. Third, the fraction of AGNs with a signature of the non-gravitational kinematics, steeply increases with AGN luminosity and Eddington ratio, while the majority of luminous AGNs presents the non-gravitational kinematics in the [OIII] profile. These results suggest that ionized gas outflows are prevalent among type 2 AGNs. On the other hand, we find no strong trend of the [OIII] kinematics with radio luminosity, once we remove the effect of the bulge gravitational potential, indicating that ionized gas outflows are not directly related to radio activity for the majority of type 2 AGNs. We will discuss the implication of these results for AGN feedback in the local universe.

• Journal of the Korean Institute of Gas
• /
• v.15 no.2
• /
• pp.21-26
• /
• 2011

Emissoin of heavy duty vehicle have much positioned in air pollution although its limited number of vehicles. CNG vehicles are coming to the fore as one of the solution of diesel vehicles. CNG vehicles exhaust smaller emission than diesel vehicles on PM and NOx. In this study, aftertreatment technologies are introduced on vehicles which use CNG and hydrogenmixed fuel. Withmixing hydrogen with CNG, combustion efficiency is enhanced, and harmful emission might be decreased, but methane that is main component of CNG brings green house effect. In order to remove methane and NOx in exhaust gas of CNG engine, methane oxidation catalyst and SCR technologies were respectively analyzed.