• Journal of Ecology and Environment
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• v.32 no.2
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• pp.115-121
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• 2009

In order to elucidate the mechanisms affecting plant distributions in the reclaimed dredging area in the Gwangyang steelworks, in the Gwangyang Bay, Korea, we examined soil characteristics and plant distributions in four study sites and a control site in the study area. Desalination occurring along a gradient with increasing elevation, resulting in decrease of soil pH, EC, P, K, Cl, Ca, Mg, and salt and an increase in soil T-N, silt, clay contents. From site 1 (the lowest-elevation site) to site 5 (the highest-elevation site), halophytes decreased in abundance and nonhalophytes increased. The dominant species in each site were: Phragmites communis, Limonium tetragonum, and 12 additional species at site 1, Carex pumila, Suaeda japonica, and 15 additional species at site 2, Spergularia marina, Scirpus planiculmis, and 22 additional species at site 3, Miscantus sinensis, Lespedeza bicolor, and 26 additional species at site 4 and Pinus thunberii, Rhododendron mucronulatum, and 39 additional species at site 5, which resembled a naturally-occurring P. thinbergii community. Cluster analysis of the vegetation data matrix grouped the 35 plots into 5 major groups, and cluster analysis using the soil environment data matrix revealed 4 major groups. CCA of the floristic and environmental data matrix showed a positive relationship of SAR, EC, Na, Cl, and Ca, which are related to salt, in the $1^{st}$ axis and $2^{nd}$ axis, but negative relationships for altitude, organic contents, silt, and clay contents. Notably, plant species in the reclaimed dredging area that were separated along the $1^{st}$ axis showed strong relationships with factors that related to salt. Long-term exposure to natural rainfall in the reclaimed dredging area changed the soil characteristics, such as salinity. This change in soil characteristics might alter the SAR, which affects plant survival strategies in a given habitat. These results strongly indicated that factors related to salt and elevation play important roles in determining the overall plant distribution in the reclaimed dredging area.

• Korean Journal of Construction Engineering and Management
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• v.13 no.2
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• pp.25-36
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• 2012

As the international construction market is rapidly expanding, Korean contractors have the need for having new leading businesses for their sustainable growth and high performance. Thus, this research tried to explore new leading businesses with two questions: 'What can be the new leading businesses?' and 'How can Korean contractors implement new leading businesses?' To this end, based on Porter's five forces framework and the resource-based view (RBV), we first derive three evaluation criteria (possibility of market entry, possibility of profit earning, and possibility of value-added earning). Next, we developed a framework for business evaluation which considers external market condition, internal competitiveness, and spin-off effects toward domestic market. Based on the framework, we defined green-energy plant, environmental plant, desalination plant, nuclear power plant, new urban development, and high-rise building as new leading business. Then, we selected green energy plant, environmental plant, and new urban development for the purpose of prior occupation of the market, consolidation of the competitiveness, and expansion of the ripple effect, respectively. Finally, we deduced market entry strategies for each business by investigating experts' opinions.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.3
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• pp.52-62
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• 2008

By analyzing specific plant distributions and physicochemical characteristics of topsoil in a reclaimed dredging area, baseline data was found of natural landscape planting sites, and developing dredged fill ground. The reclaimed dredging area is five different stands (1, 2, 3, 4 and 5) which were examined in this research. They are located from sea level to 15 meters in altitude and exhibited typical characteristics of the salt marsh in Gwangyang Bay. Species with high constancy in the vegetation on the reclaimed soil were classified into four stages. A total of 12, 15, 22, 27 and 35 different plant species were found and also increased in stands 1, 2, 3, 4 and 5, respectively. Moving from stand 1 to 5, halophytes decreased and non-halophytes increased. Desalination at each stage of the reclaimed dredging area was a driving force affecting the performance and distribution of halophytes and non-halophytes. Overall, 35 quadrats of soil were selected and analyzed for specific physicochemical characteristics of topsoil between O${\sim}$20cm. Results of the physicochemical analysis such as altitude, slope, vegetation and kind of reclaimed dredging soil, exhibited irregular increases or decreases. As survey areas moved from stand 1 to 4, desalination areas, soil acidity, electric conductions, content of salinity, available phosphorus, potassium, chlorine, calcium, and magnesium indicated decreasing patterns; however, total nitrogen, silt, and clay content increased. Cluster analysis and PCA by environmental data within the stands clearly showed five distinct vegetation patterns on the tested reclaimed area. These results indicate that the differences of performance and distribution of vegetation are due to the SAR in the reclaimed soil and related to the natural survival strategy at the given hostile habitat.

• Nuclear Engineering and Technology
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• v.31 no.5
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• pp.506-511
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• 1999

The pilot system for radioactive liquid laundry waste was developed with treatment capacity, 1ton/hr and set up in the Yong Kwang unit #4. The system is composed of tank module, RO systems and a UV/$H_2O$$_2$photo-oxidation unit. The RO system consists of the BW unit (low-pressure RO for brackish water desalination) and the SW unit (high-pressure RO for seawater desalination). The BW unit possesses 4 RO membranes and it can reduce the feed water volume down to 1/10. This concentrated feed water can be reduced again up to 1/10 in its volume in the SW unit composed of 4 RO membranes. The UV/$H_2O$$_2$ photo-oxidation process unit was used for the detergent degradation. The operation of the pilot system was carried out and verified in its capability through the continuous operation and concentration operation using the actual liquid waste from the power plant. The design criteria and data for industrialization were yielded. The efficiency of the UV/$H_2O$$_2$ photo-oxidation process and the optimum operational procedure were evaluated. The decontamination factors for radioactive cobalt and cesium were measured. This on-site test showed the experimental result in the DF$\geq$300 and volume reduction factor$\geq$100.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.216-222
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• 2021

This is an experiment to complement new ways of using concentrated water discharged from the seawater desalination plant. In this study, metakaolin, which has excellent chloride ion immobilization effect, was used as the main binder, and 10% and 20% of calcium oxide were substituted with the activator. In addition, tap-water(TW) and reverse osmosis brine water(RW) were used as mixed water. As a result of the experiment, the mixture using RW showed higher compressive strength than TW. It also showed low water absorption and high density. In the mixture using RW as mixed water, a hydration reaction substance called Friedel's salt could be observed. Considering the corrosion problem of steel, RW is considered to be applicable to products such as non-reinforced concrete, brick, and curb stone. Through this study, it is thought that it is meaningful to propose a new application method other than the ocean release of RW.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.1
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• pp.34-41
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• 2016

Using UF-SWRO hybrid process, pre-blending tests of seawater and brackish water were performed to investigate the effects on removal of boron and humic acid (HA). Feedwater pre-blending was set based on TDS concentration from 15,000 mg/L to 27,000 mg/L and analyzed for boron removal characteristics. Also organics rejection at same TDS concentration range was investigated by injecting HA. Boron concentration appeared to be high as TDS concentration was high ranging from 76.60% to 83.27%, but boron concentration in final produced water was increased up to 0.69 mg/L from 0.48 mg/L. In cases of HA tests at 10 mg/L, 22,500 mg/L TDS appeared to be higher removal rate of 17.59% than a very poor result of 8.43% in 27,000 mg/L. But high HA removal rate of 57.14% was obtained in produced water with 22,500 mg/L TDS containing 10 mg/L of HA and 27,000 mg/L TDS yielded lower boron removal rate of 54.49%. Meanwhile it was found that a relatively high flux and recovery rate were obtained following process when feedwater was injected with HA. It is considered that most of fouling substances were eliminated by binding between HA and $Ca^{2+}$. Thus, when desalination using UF-SWRO with respect to boron and HA, TDS concentration is determined to be advantageous as lower.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1368-1369
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• 2011

이 연구는 최근 물 부족시대를 대비한 차세대 기술로 각광 받고 있는 해수담수화설비의 동력을 기존의 화석연료에서 신재생에너지로 전환하고 있는 세계적인 추세와 기술동향을 살펴보고 국내 적용 가능성을 검토한 것이다. 특히 태양열, 태양광, 풍력 등을 활용하여 MENA(Middle East Asia & North Africa), 스페인, 지중해 연안 등의 지역에서 추진 중인 프로젝트의 성과를 살펴보고, 이를 토대로 극심한 물 부족으로 불편을 겪고 있는 국내 해안 도서지역에 적용할 수 있는 방안을 검토하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.705-708
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• 2011

Ejector system can induce the secondary flow or affect the secondary chamber pressure by both shear stress and pressure drop which are generated in the primary jet boundary. Ejectors are widely used in a range of applications such as a turbine-based combined-cycle propulsion system and a high altitude test facility for rocket engine, pressure recovery system, desalination plant and ejector ramjet etc. The primary interest of this study is to set up an design procedure on the configuration and operating condition of multi-ejector for the various high altitude simulation.

• The KSFM Journal of Fluid Machinery
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• v.8 no.6 s.33
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• pp.33-39
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• 2005

A thermal vapor compressor in which the subsonic/supersonic flow appears simultaneously, has been accurately designed through the CFD analysis for the various shape parameters such as the primary nozzle shape, converging duct shape, mixing tube diameter, and so on. The performance of the developed thermal vapor compressor has been experimentally verified to be installed in a Multi Effect Desalination(MED) plant as an important element. In this paper, the effects of each parameter are discussed on the basis of CFD results and the experimental results for various boundary conditions(motive pressure, suction pressure, and discharge pressure) are presented in compared with CFD results. The two results show a good agreement with each other within 2 % accuracy with regard to the entrainment ratio.

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.210-213
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• 2008