• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.3
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• pp.189-201
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• 2013

To study characteristics of the water quality in the Hansan-Geoje bay, we analyzed the long term monitoring data collected at the two sites during the period of 1987~2010. The trophic state of the waters in Hansan-Geoje bay was the mesotrophic level by the classification of Wasmud et al.[2001]. The water nutrients increased steadily from a wet season (Aug.), it reached the maximum concentration peak in a dry season (Nov.), and then decreased steadily to the winter, it reached at the minimum value in May in the next year. The result of factor analysis divided the waters of Hansan-Geoje bay into the five factors (nutrient, season, inflow land water, pollution, internal production) and the factors represented the 76.82% on the status of the waters. According to time series analysis, temperature, DO and bottom DIP were increased, and pH and COD were decreased during the period of 1987~2010. In particular, the fluctuation trend of DIN has been turned from oversupply to shortage by the N/P ratio since before and after 1990's. The water quality of the Hansan-Geoje bay has been recovered except DIP since 1987, despite of its geographical characteristic which is a general semi-closesd bay and a massive aqua-culture ground. To preserve the waters in Hansan-Geoje bay, we need to know on the cause of the increase or accumulation of DIP, and we should continue to study on the interrelation between the aqua-culture and water environment.

• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.67-78
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• 2017

This study aims to analyze the status for the improvement of rehabilitation facilities of the products manufactured by severely disabled. So, This study analyze rehabilitation facilities of 289. The results of this study were as follows. First, sheltered workshop rate is 57.1%, Welfare group of disabled is 29.8%, Work program is 13.1%. And Total worker is 8,358 people(average 28.92 people), worker with disabled is 6,119 people(average 21.17 people). Second, Most of the certificated item is printing/advertising(18.6%) and food(14.3%), office/stationary(12.8%) and so on. Third, Total sales is 17.8 million won and sale cost is 15.7 million won and net income is 2.1 million won. Also, The longer the certificated period, the higher the sales. Forth, It is supported to purchasing improve sales, improve employment of the disabled, improve wage of the disabled, improve working condition. Fifth, it is necessary to successful of extension of priority purchasing ratio, additional purchasing point, support system of market. Base on this results, the implications for improvement on rehabilitation facilities wer discussed.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.7-13
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• 2014

As the interest on the air pollution is gradually rising up at home and abroad, automotive and fuel researchers have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward various main issues : whether PM emissions should be regulated for diesel and gasoline vehicles and whether gasoline and LPG powered vehicles can be further neglected from PM emission inventories. Finally, the greenhouse gas ($CO_2$, $CH_4$, $N_2O$) regulation has been discussed including automotive emission regulation. The greenhouse gas and emissions (PM) particle of automotive had many problem that cause of ambient pollution, health effects. This paper discussed the influence of LPG fuel on automotive cold startability and exhaust emissions gas. Also, this paper assessed emission characteristics due to the test temperature. These test temperature were performed by dividing the temperature of the test mode and the lowest local temperature in winter. Through this study, the correlation of cold startability, exhaust emission and greenhouse gas emission was analyzed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.2
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• pp.130-139
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• 2015

To assess the noise stress of shrimp farms reasonably, we need a noise observation data underneath the waters first. But, it did not collect yet and airborne noise transfers to water noise wave using transition calculation. In case of construction of solar energy without noise stress protection wall, the threshold values (140 dB) from circumstance of underwater noise exceed within 17m at $S_2$ (15m away from source) and $S_3$ (15m away from source). Considering additional way to decrease the construction noise, all cases including minimum mode(Case A), general mode(Case B), and maximum mode(Case C) meet the guideline of underwater noise for fish farms. In case of the underwater noise could affect the fish farm, it is necessary to understand about farming species such as shrimp, monitoring of present states, and protection way under the construction.

• Journal of Yeungnam Medical Science
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• v.5 no.1
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• pp.69-75
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• 1988

The drinking water in the apartment is stored in reservior tank and thereafter supplied each household. In case the drinking water is stored too long or insanitary, tap water might change in quality. This study was carried out to evaluate the physico-chemical and microbiological conditions of 36 samples of tap water of apartments compared to 18 samples of tap water of independence houses in Taegu City from May to October, 1987. Main findings are summarized as follows : PH values were within normal range in all samples. Samples less than 0.2ppm in residual chlorine accounted for 16.7% in the appartment and 5.6% in the independence house. Nitrite nitrogen was detected 2.8% of apartment samples only. Among the total of 54 samples, 11.1% of the apartment and independence samples were over the normal value in standard plate count. Samples more than 1.8 of most probable number(MPN) accounted for 27.8% in the apartment and 33.3% in the independence house. In result of test for residual chlorine, nitrite nitrogen, standard plate count, and MPN, the proportion of the samples revealed inappropriated in respect of drinking water standards. In case of all sorts of tests was 2.7% in apartment and nothing in independence houses, in case of 3 sorts of tests was 2.7% in apartment and 5.6% in independence houses, in case of 2 sorts of tests was 8.3% in apartment and 5.6% in independence houses, and in case of only 1 test was 25.0% in apartment and 22.2% in independence houses. Correlation between residual chlorine and standard plate count, and between standard plate count and MPN were observed. It was found that the more years since construction of apartment were, the worse tap water was in quality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.54-59
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• 2020

Coarse aggregate is produced in various ways depending on the location and production method. Currently, the construction industry is in need of a stable supply of coarse aggregate and a way to secure standard quality. The purpose of this study is to examine whether the use of coarse aggregate in 3D printing can help solve this problem. ABS filament was selected for use in 3D printing. CATIA was used for the design of the coarse aggregate, and CUBICON Single Plus was used for the production. Six specimens were produced and cured in water for 28 days. Three of them were made with AE agent, and three were made without it. A compressive strength test confirmed that when the AE agent was used, the compressive strength was greater than the lightweight concrete design criterion specified in the concrete standard specification. This suggests that coarse aggregate produced by a 3D printer may be used for lightweight concrete. A mass production system using this method could help to solve the problems facing the construction industry, such as stable supply and demand for coarse aggregate and securing standard quality.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.12
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• pp.813-820
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• 2014

In this study, the characteristics of water quality change of the three streams in Daejeon were analyzed according to the expanded installation of interceptors and wastewater treatment plant (WTP). Gabcheon 5 (Singu Bridge) location showed the maximum difference of the highest and lowest concentrations in the last decade. However, the recent water quality of this location was worse than other locations, because of the impact of the effluent from the WTP. In the upstream of the WTP, the Daejeon stream was relatively better than the other locations in organic pollution reduction, and this was caused by the investment for the management of the interceptors in three streams of Daejeon. According to the water quality standard of the stream water quality, the recent water quality of the three streams in Daejeon was acceptable within them in the most of the water quality items, but because the total phosphorus concentration of the upstream such as Daejeon stream, Yudeng stream, Gabchen 3 location did not reach the standard values, a better management of the interceptor was required in the upstream of WTP than its downstream. The upstream of WTP also required a better management of the interceptor than the downstream. The operation and management of WTP was required a high efficiency because the water quality of the effluent from the WTP incurred an adverse effect to the target water quality in the location of the total water pollution load management system.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.710-714
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• 2009

In this study, we analyzed the desulfurization performance of Zn-based dry sorbents according to the reducing power, water vapor content and $H_2S$ inlet concentration of coal gas in a batch-type fluidized-bed reactor. We used three different coal gas composition with different reducing power such as KRW air-blown coal gas, Shell oxygenblown coal gas and IAE coal gas. The experiments were performed by changing the inlet concentration of water vapor and $H_2S$ in a coal gas. Water vapor content was varied from 5% to 30% and $H_2S$ inlet concentration from 0.5% to 2.0%. As both the water vapor content and $H_2S$ inlet concentration increased, desulfurization performance of Zn-based sorbents decreased regardless of the reducing power of the coal gas. The minimum desuflurization performance was, however, above 99.5% for all experimental conditions, which implied that Zn-based dry sorbents could be used to remove $H_2S$ up to 99%.

• Journal of the Korean Vacuum Society
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• v.11 no.1
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• pp.68-75
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• 2002

It is observed the characteristic of the microwave air plasma in the wide range of the operating pressure, 1 mTorr ~ 760 Torr. The microwave air plasma was generated by an AC-type microwave source manufactured with a magnetron taken from a commertial microwave oven and the input power was fixed at 370 W. Characteristics of the plasmas were observed by an injection Langmuir probe and an OES(Optical Emission Spectroscopy). The breakdown electric field is drastically changed at 500 mTorr. For < 500 mTorr, the ratio of the breakdown electric field and the pressure decreased inversely to the pressure, $5.7\times10^4$V/m-Torr.However, the ratio increased linearly as 43 V/m-Torr for the operating pressure, > 500 mTorr. The minimum breakdown electric field was observed about 12. kV/m at 500 mTorr. It corresponds that the input frequency equals to the collision frequency. The effective collision cross section of the air at this pressure was calculated as $9.23\times10^{-l6}\textrm{cm}^2$.The results of the OES measurement revealed that the main ions were composed of the oxygen, argon, and nitrogen for > 500 mTorr. In contrast, only oxygen and argon ions were dominated for < 500 mTorr. ion temperature of oxygen (O(II)) in the air was decreased from about 1.2 eV to 0.5 eV as the pressure increased. Langmuir probe data shows that the plasma density for < 500 mTorr was higher that for > 500 mTorr.

• Journal of the Korean Magnetics Society
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• v.26 no.5
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• pp.168-172
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• 2016

The purpose of the optimal environment of the MRI room to measured luminance and illuminance of the MRI room and the monitor. University Hospital (n = 6) of the MRI (n = 10) in the luminance and illuminance Light Probe Xi Unfors (Unfors Instruments AB, Billdal, Sweden) was measured by using the. Black luminance level and white level of illuminance is repeated three times in the middle of the side of the monitor to obtain the mean and standard deviation using a t-test statistical processing was of significance test. Monitor luminance and black level in the average $1.78cd/m^2$, the standard deviation was $0.85cd/m^2$, white level average of $43.58cd/m^2$, the standard deviation of $13.19cd/m^2$. Illuminance of MRI room was the lowest value measured in accordance with the 30.5 lux, the maximum value is 601.3 lux, mean was measured by a variety of 177.86 lux. Luminance and illuminance of the MRI room and monitor is found to have statistically significant difference (p < .05). In conclusion, refer to the recommended standard of MRI and room monitor luminance and illuminance and to create an optimal environment.