• 한국항해항만학회지
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• 제30권9호
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• pp.755-762
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• 2006

When we consider to develop a new harbor, the most important factor, we think, is the lowest water depth of waterway and approaching channel for safe navigation of vessel. The existing harbors have been being dredged to meet the international trend of jumbo sized vessels by adopting the new design criteria. As the dredged materials over the expected at the design level were common and there are still lack of land based reclamation area, we have no choice to discharge the dredged materials in open sea area In this study, we analysed the behavior of discharged materials at the dumping area of offshore, which were collected from the dredging work at the waterway in Busan New Port. We measured the tidal currents and analyzed the waters of dumping site after the dumping work. These were used to evaluate the numerical models. Suspended Solids(SS) were introduced to the diffusion model. Because of the characteristic of the dumping site, the speed of initial diffusion and settle down of the discharged materials was so fast. Therefore, we believe that the dumped materials do not cause a significant impact to the marine environment.

• 자원리싸이클링
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• 제16권4호
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• pp.3-9
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• 2007

고열 및 파절단에 의하여 폭발위험이 있는 폐리튬일차전지를 재활용하기 위해서는 폐리튬일차전지의 안정적 해체공정이 필수적이다. 본 연구에서는 폐리튬일차전지의 안정적 해체를 위한 최적 방전공정 조건을 연구하였다. $0.5kmol{\cdot}m^{-3}$ 황산용액을 이용하여 안정화를 진행한 결과, $35^{\circ}C$에는 4일째에 그리고 $50^{\circ}C$에는 1일째에 안정적 파쇄가 가능하였으며, 높은 반응온도에서 보다 빠른 안정화 결과를 얻을 수 있었다. 황산만을 사용하여 안정화를 진행할 경우, 재활용 가능한 폐리튬일차전지 금속의 손실이 크기 때문에 황산과 증류수를 이용하여 2단으로 안정화하는 공정을 제안하였으며, $0.5kmol{\cdot}m^{-3}$ 황산으로 6시간 안정화시킨 후, 증류수로 24시간 안정화한 결과, 폐리튬일차전지는 안정적으로 파쇄되었으며 금속의 손실도 적어 향후 재활용공정의 경제성 향상이 가능하다고 판단되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1463-1474
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• 2008

In order to investigate stabilization effect and sustainability on As-contaminated farmland soils which were affected the abandoned mine site and stabilized by zerovalent iron(ZVI) and industrial by-products, batch-scale and pilot-scale tests were carried out. In batch tests, ZVI and industrial by-products(blast furnace slag, steel refining slag and oyster shell powder) were used in treatment materials to reduce the As leaching. Industrial by-products were mixed with As-contaminated soils, in the ratio of 1%, 3%, 5% and 7% on the weight base of dried soil. The results of batch-scale tests was shown that the reduction of As concentration was observed in all samples and it was expected that ZVI and steel refining slag were more effective than other treatment materials to stabilize As compounds. In pilot-scale tests, columns were filled with untreated soils and treated soils mixed with ZVI and steel refining slag in the same mixing ratio of 3%. Distilled water was discharged into the columns with the velocity of 0.3 pore volume/day. During the test, pH, EC, Eh and As concentration were measured in the regular term(1pore volume). after six months, pilot-scale tests were retested to investigate sustainability of treatment materials. As a result, It was shown that the leachate from control column was continuously released during the test period and its concentration was greater than $100ug{\cdot}L^{-1}$ which was exceeded the national regulation of water discharged to river or stream ($50ug{\cdot}L^{-1}$). On the other hand, soil treated with ZVI and steel refining slag showed that the concentrations of leachate were lower than national regulation of water discharged to river or stream. Therefore it was expected that ZVI and steel refining slag could be applied to the farmland site as the alternative treatment materials.

• 자원리싸이클링
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• 제25권3호
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• pp.82-87
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• 2016

차세대 이차전지로서 주목받고 있는 리튬-공기 전지와 소듐-공기 전지를 에테류계 전해질을 이용하였을 시 방전 후 생성물을 분석 하였다. FESEM을 통하여 확인한 결과 리튬-공기 전지와 소듐-전지의 방전 후 생성된 입자의 형태는 좁쌀 모양을 보였으며, 두 전지 시스템에서 큰 차이를 보이지 않았다. 하지만 XRD를 통하여 확인 하였을 시 리튬-공기 전지는 비정질 형태의 $Li_2O_2$ 그리고 소듐-공기에서는 결정질의 $NaO_2$가 생성되는 것을 확인 할 수 있었다. 본 연구를 통하여 차세대 전지 시스템으로 주목받고 있는 리튬-공기 전지와 소듐-공기 전지의 기본적인 구동 원리를 이해할 수 있었다.

• Journal of Radiation Protection and Research
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• 제9권2호
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• pp.112-117
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• 1984

A lot of radioisotopes are applied to medical fields. It's very important to measure the activities on airborne radioiodine discharged in air from $Na^{131}I$ solutions and from patients treated with radioiodine. Also surface decontamination is another one important problem to be completly solved in the isotope laboratory where there is always the possibility of radiation contamination. The Authors measured the activities on airborne radioiodine with RI collector and scintillation counter. 1. The mean accumulative activity of airborne radioiodine discharged into air from $Na^{131}I$ solution was measured as $1.3{\times}10^{-3}/hr$ rate, and the maximum value was $1.8{\times}10^{-3}/hr$. 2. Radioactivity rate per hour of airborne iodine discharged into air from patients treated with $Na^{131}I$ was measured as $6.2{\times}10^{-5}/hr$ at 8 hour after administration of radioiodine and decreased into $2{\times}10^{-6}/hr$ after 24 hour. 3. Metalic surfaces such as stainless steel or aluminum are decontaminated 5 to 6 times more rapidly than wood and concrete surfaces. 4. Decontamination with wet wiping with detergent was 9 to 10 times more rapidly than dry wiping method, but dry wiping was useful for the first step to prevent spreading and flowing from liquid radioactive materials.

• 한국인쇄학회지
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• 제23권2호
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• pp.129-141
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• 2005

The liquid film behavior between two rotating rollers has been analyzed for many years. Their contributions were, however, limited almost within the areas of polymer laminar flow in there. When the slip contact of two rotating rollers is used as a role of vehicle to distribute the liquid discharged on to each roller after splitting from the nip, there was few available relationship to control the roller speed and to design system. On this work it was possible to get out a certain relationship between the discharged film thickness ratio and the roller surface seeds without any help of pressure limit at the splitting point. The hydrodynamic analyzation of Newtonian liquid behavior around the point was well proved on some manipulative experiment. The thickness ratio increases along with the roll surface speed ratio increases. And the discharged volume flow rate ratio on each roller surface varies with square of the speed ratio. Both of these relationship have a decision factor also made up by the speed ratio.

• 한국안전학회지
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• 제21권1호
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• pp.133-140
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• 2006

1997년 도쿄의정서(protocol)에서는 지구환경오염에 대한 오염원방지를 제안하는 협정으로 우리나라에서도 배출기준에 감소하기 위한 노력의 일환으로 건축자재에 대한 방출농도 기준을 마련하고 있는 실정이다. 그러나, 최근 건축공사에는 많은 종류의 건축자재와 내장재료가 사용되고 있으며, 특히 화학기술의 발달로 복합재료로 구성된 건축재료들에 대한사용이 증가하고 있다. 실내건축자재에서 방출되는 물질로 인하여 재실자들에게 두통, 현기증, 메스꺼움, 졸음, 집중력 감퇴 등의 각종 질병을 불러일으키는 '새집 증후군'과 같은 현상을 야기 시켜 건강 상 많은 영향을 주고 있는 것으로 조사되고 있으며, 이러한 문제 해결을 위해서는 각 나라마다 건축물에 사용되어 지는 건축자재에 대한 유기 화합물의 방출농도를 최소화하는 친환경 건축자재의 선정을 권고하는 실정이다. 이에 본 연구에서는 건축자재의 TVOCs 에 대한 HCHO의 등급기준을 제안하고자 한다.

• 한국전기전자재료학회논문지
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• 제32권4호
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• pp.320-326
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• 2019

Recently, the application of atmospheric plasma technology in air filtration is increasing. Sterilization by an atmospheric plasma device is very effective. However, ozone gas, which is generated during atmospheric plasma formation, poses a hazard to human health. To reduce the ozone gas during plasma discharge, we fabricated a one-plate hybrid plasma discharge device with a heating element, which can decompose ozone gas effectively by a simple heating action. In this study, we evaluated the plasma discharge characteristics and ozone concentrations with various Ar flow rates and temperatures. With increasing Ar gas flow rate, the ozone concentration and spectrum intensity increased till an Ar gas flow rate of 60 sccm, and decreased thereafter. When discharged in high temperature, the ozone concentration and spectrum intensity decreased. Further, to evaluate the state of the treated surface under various plasma discharge and heating conditions, we measured the variation in the contact angles on the surface. Regardless of the temperature, the contact angle increased with increasing discharge voltage. However, the contact angle increased when discharged at high temperature.

• 상하수도학회지
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• 제28권4호
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• pp.479-489
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• 2014

Membrane backwashing waste shows seasonally different characteristics and it has bad settleability differently from general backwashing waste in water treatment plant. When chemicals was injected to membrane backwashing waste, the settleability was better than chemicals was not injected. However, when settled lower sludge was not discharged, flowing sludge continuously was concentrated over a certain surface and floatation penomena occurred according to flowing velocity. When the lower sludge was discharged continuously in the thickener to prevent floatation penomena of turbidity materials, the depth of sludge surface was the least and the settleability increased.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2007년도 추계학술대회 및 정기총회
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• pp.16-19
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• 2007

At an integrated steel mill, raw materials such as coal and iron ore are discharged by ships through multiple unloaders. The discharged raw material is then transported to storage yards through multiple routes established simultaneously on a fairly complicated belt conveyer network. Formulating an efficient unloading schedule is a quite cumbersome task due to the insufficient number of berths and unloaders as well as the potential conflict among routes being used simultaneously. In this paper, we propose a solution approach to the scheduling problem and describe the prototype system that we built as an implementation of our approach.