• Journal of the korean society of oceanography
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• 제32권1호
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• pp.17-27
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• 1997

Miami Isopycnic Coordinate Ocean Model is applied to the East Sea to estimate the renewal time of the upper Intermediate Water The model gives about 10 years of renewal time. Extrapolating this result to the whole water mass below, including the upper Intermediate Water, leads to about 81.4 years of renewal time, which is quite comparable to that obtained by Kim and Kim (1997) based on the recent observations. Deep winter mixing occurs in the north of the basin. The areas of the largest water mass conversion, from the upper mixed to the intermediate below, are along the periphery of the deep mixing zone. Large portion of the renewed Intermediate Water then advects along the Korean and Japanese coasts. It is concluded that the high-oxygen content Intermediate Water found off the Korean coast (Kim and Chung, 1984) is in part locally formed but mostly advected from the deep mixing zone.

• Restorative Dentistry and Endodontics
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• 제18권2호
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• pp.507-513
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• 1993

본 연구의 목적은 3종의 일반적 glass ionomer cement과 1종의 광중합형 glass ionomer cement을 자료로 하여 연화후 3, 5, 7, 10분 경과시켜 methylene blue용액에 침적하여 그침투를 측정하여 물의 영향을 관찰하고 이상의 시간과 관련하여 수분과 접촉시 그 용해도를 zinc phosphate와 polycarboxylate cement와 비교관찰하였다. blue stained zone은 모든 glass ionomer cement에서 나타났고 inner opaque zone은 두종의 regular glass ionomer cement에서만 나타났다. 연화시작부터 물에 침적시키는 사이시간이 연장되매 따라 모든 cement에서 두 zone의 후경이 감소하였고 regular glass ionomer cement의 면으로 부터 물질의 손실량은 현저히 감소하였으며 물질의 손실량에 대해서는 light curing glass ionomer cement는 시간에 거의 영향을 받지 않았으며 zinc phosphate cement파 polycarboxylate cement도 이와 유사성을 보였다.

• 태양에너지
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• 제9권1호
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• pp.30-35
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• 1989

This paper dealt with an experiments on temperature vairation in the heat storage zone due to change of vertical location (height) of sink diffuser and flow extraction in small saltless solar pond ($0.5{\times}0.5{\times}1.0M$), and the honeycomb device for this experimental purpose consisted of one-tired, sealed, and air filled by honeycomb panels. As results of experiments, 1) The storage zone was formed under lower region below the honeycomb device. 2) The higher vertical location of sink diffuser was placed, the more mixing phenomenon increased in the pond at steady flow extraction. 3) The more flow extraction increased, the more mixing phenomenon decreased at constant heat exchanger and variable flow extraction.

• Advances in concrete construction
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• 제9권1호
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• pp.55-70
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• 2020

In this research article, acid resistance, sulphate resistance and sorptivity of self compacted concrete (SCC) prepared from C&D waste have been discussed. To improve the above properties of self compacted recycled aggregate concrete (SCRAC) along with mechanical and durability properties, different two stage mixing approaches (TSMA and TSMAsfc) were followed. In the proposed two stage mixing approach (TSMAsfc), silica fume, a proportional amount of cement and a proportional amount of water were mixed in premix stage which fills the pores and cracks of recycled aggregate concrete (RAC). The concrete specimen prepared using above mixing approaches were immersed in 1% concentration of sulphuric acid (H2SO4) and magnesium sulphate (MgSO4) solution for 28, 90 and 180 days for evaluating the acid resistance of SCRAC. Experimental results concluded that the proposed two stage mixing approach (TSMAsfc) is most suitable for acid resistance and sulphate resistance in terms of weight loss and strength loss due to the elimination of pores and cracks in the interfacial transition zone (ITZ). In modified two stage mixing approach, the pores and cracks of recycled concrete aggregate (RCA) were filled up and make ITZs of SCRAC stronger. Microstructure analysis was carried out to justify the reason of improvement of ITZs by electron probe micro analyser (EPMA) analysis. X-ray mapping was also done to know the presence of strength contributing elements presents in the concrete sample. It was established that SCRAC with modified mixing approach have shown improved results in terms of acid resistance, sulphate resistance, sorptivity and mechanical properties.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권7호
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• pp.90-102
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• 2015

To understand the hyrogeochemical variation of bedrock aquifer during underground space construction, various graphical methods including multiple-component plots and chemical trends were used to estimate the mixing rate between seawater and freshwater and to investigate the evolution of water quality. The water chemistry and mixing rate between fresh and sea waters, which are generally localized in the construction area (MW-7, in land), shows typical characteristics of freshwater that doesn’t affect its validity as seawater intrusion. Especially, the water chemistry of a MW-4 (coastline) was classified as Na-Cl type, Na-HCO₃ type, and Ca-Cl type due to the influence of the seawater intrusion. And hydrogeochemical and isotopic data show that local freshwater is subjected to geochemical processes, such as reverse ion-exchange. Throughout the Chadha’s diagrams, four different case histories with the temporal and spatial variation of groundwaters in the study area were proposed, which is recommended to interpret the hydrogeochemical reactions effectively.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.113-199
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• 2002

In this study, the toughness was evaluated by using the instrumented Charpy impact testing procedures for A15083-O aluminum alloy used in the LNG carrying and storing tank. The specimens were GMAW welded with four different mixing shield gas ratios (Ar100%+He0%, Ar67%+He33%, Ar50%+He50%, and Ar33%+He67%), and tested at four different temperatures(+25, -30, -85, and -196$^{\circ}C$ ) in order to investigate the influence of the mixing shield gas ratio and the low temperature. The specimens were divided into base metal, weld metal, fusion line, and HAZ specimen according to the worked notch position. From experiment, the maximum load increased a little up to -85$^{\circ}C$, and the maximum load and maximum displacement were shown the highest and the lowest at -196$^{\circ}C$ than the other test temperatures. The absorption energy of weld metal notched specimens was not nearly depends on test temperature and mixing shield gas ratio because the casting structure was formed in weld metal zone. In the other hand, the others specimens was shown that the lower temperature, the higher absorption energy slightly up to -85$^{\circ}C$ but the energy was decreased so mush at -196$^{\circ}C$

• Journal of Advanced Marine Engineering and Technology
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• 제26권6호
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• pp.653-660
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• 2002

In this study, the toughness was evaluated by using the instrumented Charpy impact testing procedures for A15083-O aluminum alloy used in the LNG carrying and storing tank. The specimens were GMAW welded with four different mixing shield gas ratios (Ar100%+He0%, Ar67%+He33%, Ar50%+He50%, and Ar33%+He67%), and tested at four different temperatures(+25, -30, -85, and $-196^{\circ}C$) in order to investigate the influence of the mixing shield gas ratio and the low temperature. The specimens were divided into base metal, weld metal, fusion line, and HAZ specimen according to the worked notch position. From experiment, the maximum load increased a little up to -$85^{\circ}C$ , and the maximum load and maximum displacement were shown the highest and the lowest at -$196^{\circ}C$ than the other test temperatures. The absorption energy of weld metal notched specimens was not nearly depends on test temperature and mixing shield gas ratio because the casting structure was formed in weld metal zone. In the other hand, the other specimens were shown that the lower temperature, the higher absorption energy slightly up to $-85^{\circ}C$ but the energy was decreased so mush at $-196^{\circ}C$.

• 설비공학논문집
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• 제12권10호
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• pp.879-885
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• 2000

It is a serious subject for energy conservation to prevent the energy loss caused by mixing of heated and cooled air jets in a building which two types of air-conditioning systems are adopted in perimeter and interior zone. The purpose of this paper is to clarify the quantitative and qualitative mechanisms of the mixing loss and to propose preventive methods for it. In this paper, by using the dynamic heat load calculation method, heat extraction loads of a typical office building in Pusan are calculated. According to the results, numerical simulation based on the computational fluid dynamics were peformed in order to measure the mixing loss in physical size HVAC system. Then, the distributions of air temperature and velocity are analyzed in order to grasp the relations by setting temperature differences influence on the mixing loss.

• 한국항해항만학회지
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• 제28권10호
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• pp.947-953
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• 2004

연안에서 대규모 항만개발이 단계적으로 진행되고 항만 부근역에서의 인구가 더욱 더 증가되면서 항만의 오폐수 및 도시하수의 처리방안에 대한 문제가 관심을 끌고 있다. 오폐수를 1차 또는 2차 처리한 후 수중 방류관을 통해 해안이나 심해 또는 그 중간지점에서 방류하는데, 오폐수가 방류되면 주변 해수를 연행하여 플룸, 제트 또는 부양성 제트의 형태로 해수면까지 상승하면서 크게 희석된다. 본 연구는 효율적인 해양방류시스템의 설계시 간과되어온 계절적, 공간적인 해수온도의 변화에 따른 플룸의 거동 및 희석 특성에의 영향을 다루고자 한다. 방류수의 수온 뿐 아니라 방류지점의 계절적 주변수의 온도변화를 고려하여 CORMIX-GI을 적용하였다. 결과를 방류수의 혼합역 특성을 평가하는데 사용시에는 주의하여야 한다. 이 연구가 방류관의 효율적 운영, 바람직한 방류관의 설계, 수질보호, 발전소의 온배수 방류문제 등에 도움이 되기를 바란다.

• 한국물환경학회지
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• 제32권5호
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• pp.419-432
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• 2016

이 연구의 목적은 응천에서 채집한 담수 붕어(Carassius auratus)의 산화적 스트레스와 조직병리학적 손상을 분석하여 하수처리장 방류수의 영향을 평가하는 것이다. 방류수 혼합 지점과 하류 지점에서 채집한 붕어의 아가미, 간, 콩팥의 과산화수소 분해효소(catalase)의 활동도는 상류 지점과 비교하여 더 높은 것으로 나타났다. 또한, 혼합 지점의 아가미와 간의 글루타치온 S-전이효소(glutathione-S-transferase)의 활동도는 상류 지점과 비교하여 유의하게 높았으며(p < 0.05), 상류 지점보다 유의하게 더 증가된 간의 지질 과산화(lipid peroxidation)가 혼합 지점에서 관찰되었다. 붕어의 조직병리학적 손상의 정도는 간 > 콩팥 > 아가미순으로 나타났다. 이 결과는 간이 방류수의 영향을 가장 크게 받는다는 것을 의미한다. 붕어의 조직 손상도(degree of tissue changes)는 혼합 지점에서 채집한 시료(30.98 ± 5.40)에서 가장 컸으며, 그 다음은 하류 지점 시료(19.28 ± 4.31)이고 가장 낮은 것은 상류 지점 시료(4.83 ± 2.67)로 나타났다. 이러한 결과는 혼합 지점에서 채집한 붕어가 방류수에 가장 큰 영향을 받았다는 것을 의미하며, 산화적 스트레스와 조직병리학적 지표들이 방류수로 오염된 하천을 모니터링하는데 유용하다는 것을 나타낸다.