• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.66-78
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• 2003

The effects of several factors such as heavy metals, living microorganims, high molecular conglomerator in sewage sludge were analysed. And the effects of the sewage sludges which were mixed with other organic waste such as paper mill sludge or night soil sludge upon the feeding rate and biomass of earthworm population were also estimated. The earthworm populations could not survive when newly produced sewage sludges were fed without any pretreatment. The contents of heavy metals were under the levels that could inhibit earthworm's growth. The living microorganisms and the high molecular conglomerator in the sewage sludge had no relations with ecotoxicological effects of sewage sludge upon the earthworm population. Sewage sludge which had been mixed with paper mill sludge and aged for more than 21 days showed no ecotoxicological effects on tiger worm(Eisenia fetida) population. And the feeding rate of earthworm population and the turnover rate of earthworm biomass were higher in those sewage sludges than in the sewage sludges pretreated by other ways.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.6
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• pp.656-665
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• 2012

Recently, yearly production of SRF (Solid Recovered Fuel) as an alternative fuel has been rapidly increasing because of the limited waste disposal, rise in oil prices and reduction of greenhouse gas emission. However, SRF using facilities are excluded from the National Air Pollutant Emission Estimation because SRF using facilities are not yet included among the SCC (Source Classification Code). The purpose of this research was to estimate the emission and emission factor of SRF using facilities' PM and $NO_x$, in order to investigate whether or not they are included in the National Air Pollutant Emission Estimation. The emission factors of SRF using facilities' PM and $NO_x$ are calculated as 0.216 kg/ton, and 3.970 kg/ton, and the emission was estimated based on the yearly total SRF usage of 2011. The results above was 18.7% for PM and 12.8% for $NO_x$ emissions from combustion facility (SCC2) in manufacturing industry combustion (SCC1) of CAPSS. If CAPSS estimate the emission by adding SCC on unlisted SRF in case of Boiler (SCC3) fuel, both PM and $NO_x$'s emissions would increase by 15.8% and 11.3% compare to the emissions for the existing combustion facility. As a result, emissions caused by SRF should be considered when calculating the National Air Pollutant Emission Estimation. In addition, further researches to develop emission factor and improve subdivided SCC should be done in the future, for the accurate and reliable estimation of National Emission.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.107-113
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• 2012

Pollutants in aquaculture system effluent mostly originated from solid wastes including uneaten feed and excreta of cultured species. In this research, DAF(Dissolved Air Flotation) unit is suggested as an integrated solid control unit especially as a form of IIBG(Inline Injection Bubble Generation) process in aquaculture system. Solid removal performance of DAF unit was examined under various operation and salinity conditions with turbidity and suspended solid. Solid waste removal efficiencies were found to be affected by operation conditions including saturator pressure, recycle ratio, coagulant concentration. Solid removal efficiency was higher under higher saturator pressure and recycle ratio under which condition larger number of bubbles is generated. Coagulant is thought to have important role in creating bubble-particle aggregate by showing better removal efficiency with higher concentration. However higher saline water showed less effectiveness in removing solids by DAF(IIBG). Application of DAF(IIBG) process also showed additional effect in phosphate removal and DO(Dissolved Oxygen) supply. Phosphate existed in polluted water was removed up to 46% after treatment, which is thought to attribute to aluminium phosphate precipitation. And DO concentration was found to increase over 50% of initial saturation concentration after the injection of micro-bubbles. Through experiments on solid removal from aquaculture effluent, DAF(IIBG) process is estimated to be effective solid control method. This property can help aquaculture system being installed and operated simply and effectively.

• Journal of the Korean Vacuum Society
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• v.15 no.4
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• pp.338-346
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• 2006

In semiconductor process, it is so hard to predict an exact failure point of the vacuum pump due to its harsh operation conditions and nonlinear properties, which may causes many problems, such as production of inferior goods or waste of unnecessary materials. Therefore it is very urgent and serious problem to develop diagnostic models which can monitor the operation conditions appropriately and recognize the failure point exactly, indicating when to replace the vacuum pump. In this study, many influencing factors are totally considered and eventually the monitoring model using multivariate statistical methods is suggested. The pivotal algorithms are Multiway Principal Component Analysis(MPCA), Dynamic Time Warping Algorithm(DTW Algorithm), etc.

• Korean Journal of Construction Engineering and Management
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• v.2 no.4 s.8
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• pp.117-126
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• 2001

The purpose of this study is to present a way of Variation Control in building construction process. The study suggest a way of the application method of shielding, decoupling concept and also Poka-yoke device to control variation that occurs from uncertainty in construction industry with lots of waste factors. The main contents of the study are as follows; (1) It's suggested strategy to apply shielding, decoupling as variation control technique. (2) Current Poka-yoke devices are investigated and analyzed. As a future research, it is required to study continuously on the more effective application method of Poka-yoke device and on existing examples in domestic construction sites for the process improvement.

• 한국해양학회지
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• v.21 no.1
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• pp.56-71
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• 1986

In order to clarify the influence of environmental factors on the phytoplankton cmmunity in Kyeonggi Bay, the hydrological and water quality data were obtained from 20cruises from May, 1981, to September, 1982 in this bay. Physical conditions at the mouth of the bay are more stable than those at the head of the bay. Temperatures and salinities of the upper part of the bay show great seasonal fluctuations due to the river discharge. By the extending effects of freshwater, a weak two-layer flow system is formed from the upper part of the bay to Palmi Island. In summer thermal stratification are formed in the middle and outer parts of the bay. In winter, However, the temperature shows no vertical temperature gradient. The inner bay and the vicinity area of Incheon Harbour are relatively polluted and eutrophicated due to both the runoff of freshwater from the Han River and the waste discharge from Incheon industrial complex. However, except the polluted area, the study areas are well oxygenated with more than 90% saturation.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.84-87
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• 2001

A demand for the aggregates is increasing in the field of civil and architectural industry and so on. In these industries, the particle size and shape of aggregates are important factors and especially spherical or rounded particles are desired. In Japan, waste glass is used as one of the aggregate materials for the pavement or the construction. In this study based on the frictional action of material on each other, an autogenous grinding of silica glass with a stirred mill were carried out in order to eliminate flakelike or squarish particles and get spherical or rounded ones for aggregate materials. The autogenous grinding experiments were conducted by applying loads to the particle layer of silica glass. The particle shape was evaluated by the shape index, N/T and the degree of circularity, Ψ$_{ci}$ . The unfractured particles (20~13mm) were evaluated by N/T and Ψ$_{ci}$ , and the products (finer than 10${\mu}{\textrm}{m}$) by Ψ$_{ci}$ . As a result, N/T of the unfractured particles decreased with an increase of grinding time. Ψ$_{ci}$ of the unfractured particles and the products increased with an increase of grinding time (; progress of grinding), and became almost constant in the long time grinding. These tendencies were not changed by the applied load on the particle layer, but the limit value of Ψ$_{ci}$ at the products were varied with the applied load.plied load.

• Journal of the Korea Society of Computer and Information
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• v.19 no.8
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• pp.19-26
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• 2014

Analysis of influential factors on water consumption in households will help predicting the water demand of end-use in household and give an explanation to cause on the change of trend. In this research, the data are gathered by radio telemetry system which is combined electronic flow-meter and wireless communication system in 140 household in Korea. Using this data, we estimate for each residential type to determine liter per capita day. we used real data to predict bathtub and washbowl water-uses and compared the ordinary least square regression model and autoregressive regression error model. The results of this study can be applied in the planning stages of water and waste water facilities.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.8
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• pp.439-447
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• 2009

Cogeneration system produces power as well as heat recovered from waste heat during power generation process. This system has higher energy efficiency than that of the power plant. In this study the optimal design for the cogeneration system with the increase of the capacity considering life cycle cost(LCC) analysis has been performed in the general facilities such as hotels and hospitals under the assumption of electricity cost of 95 won/kWh, the initial cost of cogeneration system of 1,500,000 won!kW and the value of 0.5${\sim}$1.0 in the ratio of heat to power. The optimal ratio of cogeneration capacity divided by average electricity load of facility was found out more than 0.5 in case of electricity cost with the increase of>30%, and the percentage of $CO_2$ reduction was about 9%. The most important factors in the economic analysis of cogeneration system was found out the electrity cost and the initial cost of cogeneration system. Also the ratio of heat to power at the value of>0.5 was not affected in the economy of cogeneration system, but was very important in the $CO_2$ reduction.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.217-217
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• 2017

Seed priming leading to improved emergences, germination speed and uniformity under unfavorable conditions without loss of longevity are the best level of techniques. We studied the possibility to obtain primed seed with reduced mean germination time (MGT) and uniformity but with simple, fast and effective methods. The experiments were carried out at $15^{\circ}C$ for 16 hours with priming treatment. To compare the effects of each treatment, we used 200mM $CaCl_2$ priming or hydro priming or no imbibition after ultrasonication or red light treatment. The light treatment was performed by irradiating 2000 lux of red light for 15, 30, 60, and 120 minutes. Addition, in order to investigate the effect of the priming solution, treated at 200mM $CaCl_2$ for 8 hours. Ultrasonication treatment was performed for 5, 10, and 20 minutes at exposures of 13.0, 17.3, and 21.6 kHz during priming. For liquid smoke (LS) treatment, seed soaked in 0%, 0.5%, 1.0%, 5.0% and 10.0% of diluted water and 200mM $CaCl_2$ solution. After each treatment, the seeds were dried to moisture content ranged 5-8% at $25^{\circ}C$ for 24 hours. The effect of seed treatment was evaluated with germination percentage (GP), MGT, germination index(GI), germination rate(GR), Germination Uniformity(GU) and heath seed percentage(HS). For several factors tested, we found that the desired germination improvement could be obtained by treating the seed with ultrasonication at 17.3 kHz for 5 minutes in water or red light exposure at 2000 lux for 120 min in water that resulted very similar to those used to 200mM $CaCl_2$ priming for 16 hrs. However, LS treatment showed no improvement in all diluted solution. Therefore, the methods applied ultrasonication and red light treatment showed high potential for fast and easy treatment avoiding pollution of salt solution waste.