• Journal of Advanced Marine Engineering and Technology
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• 제22권4호
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• pp.529-537
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• 1998

Currently as due to the rapid development of industry and increase in population we meet serious problems concerning the shortage and pollution of water. In the country many experts predict a shortage of water approaching 450 million tons by the year 2006. To cope with this serious problem it is necessary to construct desalination plants. In the adoption of a desalination system the most important factor is the cost of fresh water production,. In general LNG is stored in a tank as a liquid state below $-162^{\circ}C$. When it is serviced, however the LNG absorbs energy from a heat source and transforms to a high pressure gaseous state. During this process a huge amount of cold energy accumulated in cooling LNG is wasted. This wasted cold energy can be utilized to produce fresh water by using a sea water freezing desalination system. In order to develop a sea water freezing desalination system and to establish its design technique qualitative and quantitative data regarding the freezing behavior of sea water is required in advance, The goals of this study are to reveal the freezing behavior of sea water is required in advance. The goals of this study are to reveal the freezing mechanisms of sea water to measure the freezing rate and to investigate the freezing heat-transfer characteristics,. The experimental results will provide a general understanding of sea water freezing behavior in a rectangular vessel cooled from above.

• 동력기계공학회지
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• 제17권6호
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• pp.102-107
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• 2013

In this paper, the performance analysis for evaporation capacity, total work and efficiency of the ocean thermal energy conversion(OTEC) power system using mixed refrigerant(R32,R152a) is conducted to find the effect of hot wasted water on OTEC power system. The system in this study is applied with two stage turbine, regenerator, cooler and separator on Organic Rankine Cycle. The commercial program HYSYS is used for the performance analysis. The main results were summarized as follows : The efficiency of the OTEC power cycle has a largely effect on the evaporation capacity and total work. As increasing temperature of heat source water, evaporator's capacity is decreased but total work increase. Otherwise, using hot wasted water bring effects not only increasing system efficiency but also declining evaporator's capacity. Thus With a thorough grasp of these effect, it is necessary to find way to use hot wasted water emitted by power plant and so on.

• 한국건설순환자원학회논문집
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• 제6권3호
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• pp.199-206
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• 2018

아스팔트의 재활용 기술은 화석연료 감소, 탄소 저감, 포장 성능 개선 등의 장점으로 인해 지난 20년간 선진국의 도로 건설 및 유지관리를 위해 개발되고 적용되고 있다. 상온 재생 아스팔트 혼합물은 상온에서 폐아스콘 순환골재를 물과 유화 아스팔트와 함께 혼합하는 역청재료이다. 본 논문은 폐아스콘 순환골재 혼입율에 따라 알칼리 활성화 채움재를 사용한 상온 재생 아스팔트 혼합물의 특성을 검토하고자 하였다. 그 결과 폐아스콘 순환골재의 혼입율이 증가할수록 상온 재생 아스팔트 혼합물의 마샬 안정도가 감소하고 공극률이 증가하였다. 또한, GR에서 정하고 있는 상온 재생 아스팔트 혼합물의 입도 기준을 모든 골재 혼합 조건에서 만족하였다.

• 상하수도학회지
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• 제32권6호
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• pp.507-515
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• 2018

The results of the survey on water utilization status, the wasted water factor, the awareness, and the education and promotional activities of water saving in Daejeon City are as follows: The percentage of using tap valve with a closure was 66% when showering. 74% of water was used with closing the tap valve when washing faces with no water needed, it was still considered that there existed a wasting water. The most wasting reasons of water were found to be shower, bath, and laundry in order. In the awareness of practicing tap water saving, 9.1% of respondents acted actively, 53.4% of them were trying to practice it, and more than 63% had a positive awareness. In the contents of practicing saving water, locking water when soaping while showering, non-laundry of small quantity, and using cups when brushing teeth were top priorities. About 50% of the reasons for saving water was to practice purely saving water, when saving for economic help was excluded. The level of water saving awareness was not high when considering that the ratio of usage without water saving equipment and installation, and using method was relatively high when moving in. In order to make usage of water saving equipment more common, it was deemed necessary to provide information on the purchase of water saving equipment and to promote and educate the efficiency of saving of related products. More than about 90% of the respondents responded that water saving education or promotional activities had an effect of improving water saving awareness. The most effective method of education and promotional activities was found to be 40.4% by mass media activities, and 21.7% by promotions through mobile devices.

• 대한환경공학회지
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• 제27권2호
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• pp.145-150
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• 2005

본 연구에서는 폐콘크리트 재생골재를 활용한 친환경적 폐광미 매립지 사면에 대한 폭넓은 수치해석을 수행하였다. 이를 위해 먼저 콘크리트 재생잔골재와 폐광미의 물리 역학적 재료 특성을 조사하였고, 재생잔골재가 물(지하수/우수 가정)과 반응하여 알칼리 발생에 따른 지반침하발생 여부 및 재료적 특성 변화도 살펴본 후 이를 바탕으로 사면안정해석을 집중 수행하였다. 재생잔골재와 물의 반응 실험결과, 재생잔골재에서 $OH^-$의 용출로 인한 침하는 발생하지 않았고, 투수계수, 공극률, 흡수율에서도 미미한 차이만이 발생하였으므로 이를 사면해석시 고려하지 않았다. 폐광미와 재생잔골재를 층으로 다져서 매립하는 임의 사면에 대한 수치해석 수행 결과, 사면의 안전율은 사면경사가 완만할수록, 재생잔골재 층의 두께가 커질수록, 사면 내 수위가 낮을수록 증가하는 경향을 보였다. 그러므로 폐콘크리트 재생잔골재를 활용한 친환경적 폐광미 매립지 설계 및 시공시 매립지 사면의 경사, 재생잔골재 층의 두께, 사면 내 수위에 대한 고려를 반드시 하여야 한다.

• 한국물환경학회지
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• 제20권5호
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• pp.466-472
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• 2004

Red mud is formed as a waste during bauxite refining known as Bayer's process. Its main constituents are iron, aluminium, sodium and silica. The disposal of large quantities of wasted red mud causes a serious ecological problem. In this study, the red mud wasted from the bauxite refinery was studied for phosphate removal from aqueous solution according to activation methods. The influence of heat treatment, and neutralization with sea water and acid treatment level for the optimum conditions for phosphate removal have been determined. Heat treatment combined with acid treatment is most suitable for the removal of phosphate from aqueous solution. The optimal condition was activated with 1 N HCl solution after heating in $600^{\circ}C$ during 4 hours. Acid and heat treatment causes sodalite compounds which hinder the phosphate adsorption to leach out. The adsorption data obtained followed a first-order rate expression and fitted well with the Freundlich Isotherm well.

• 조명전기설비학회논문지
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• 제14권2호
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• pp.83-88
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• 2000

본 연구에서는 공장설비 방출폐수 감시를 위한 저가격의 데이터 수집 및 저장창치를 제안하였다. 제안된 시스템은 원칩 마이크로 콘트롤러를 이용하여 시스템의 회로를 간소화하였다. 구현된 시스템은 별도의 착탈 가능한 저장용 RAM 카드를 사용하여 데이터흘 손쉽게 수집할 수 있도록 하였다. 또한 수집 데이터의 분석를 위하여 ethernet에서 사용되고 있는 CSMA/CD방식에 적용하여 모니터링 컴퓨터와의 데0]터를 전송할 수 있도록 하였다. 본 연구에서는 이러한 데이터 수집 및 저장장치를 이용하여 하천으로 유입되는 폐수량에 대한 정보를 수집하였다. 수집된 수질정보는 오염 원인이다 경과를 분석하기 위하여 데이터베이스 구축에 사용되었다.

• 공업화학
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• 제16권5호
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• pp.614-619
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• 2005

폴리올, 실리콘 수지, 변성 실리콘 수지 등을 유화제로 유화시켜 수용성 소포제를 제조하였다. 제조한 소포제에 대하여 소포성, 상분리 시간, 점도 등을 측정하였다. PPG 혼합물의 상분리 시간은 PPG 400>PPG 3000>PPG 1000이었다. PPG 1000을 혼합하였을 때는 다른 것에 비하여 뛰어난 소포성을 나타내었다. 실리콘 수지 혼합물의 상분리 시간은 TSF-451-350>TSF-451-200>TSF-451-50이었다. TSF-451-50을 혼합하였을 때는 상용성 부족으로 혼합물의 부피가 증가되었다. 고분자량의 실리콘 수지를 사용할수록 소포성은 좋지 않았다. 변성 실리콘 수지는 물에 잘 분산되었지만 폴리올에 대한 상용성은 좋지 않았다. 유화제에 대한 소포성은 SPAN 20>SPAN 60>SPAN 80의 순이었다. SPAN 80은 실리콘 수지에 대하여 혼합성이 좋지 않았지만 YAS 6406이나 PPG 1000에 대해서는 좋은 혼합성을 나타내었다.

• 한국환경교육학회지:환경교육
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• 제2권1호
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• pp.92-99
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• 1991

According to our secondary school curriculum for natural science and technical circles, there be used 353 of chemical reagents including 24 kinds of harmful and toxicant components. At present, most school are discharging their school laboratory waste water without any chemical and physical treatments. So as to solve the environmental problem for water pollution, this study tried to research a kind of adsorbant utilizing saw dust, wasted wood sources and designed the simple processing system using the adsorbent. This adsorbent was made by extracting lignin substances from raw saw dust under the solution of 0.5N-NaOH at the temperature of $100^{\circ}C$. Their metal removed rates was measured not only by processing of column and vessel. but also by comparing the standard solution and real waste water. The results were proved as more than 90(%) of the adsorptive efficiency on the average from Pb, Cd, Cu except Cr(VI)in case of the school experimental waste water soaked in vessels a long with 4g of the adsorbent for 24 hours. The new processing system enables to remove most harmful and toxicant metals by filtering, sedimenting and adsorbing at the low cost.

• 한국환경과학회지
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• 제7권5호
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• pp.623-631
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• 1998

Pyrite contained in wasted ore dumps induces a strong acid environment when it contacts oxygenated rainfall. Present research was designed to evaluate the pollution of an area that is supposedly contaminated by pyrite of ore wasted dumps form in Chonju Il Mine. Measured are the pH and selected heavy metal elements in the supposedly polluted hydrologic system. The samples include three types : those collected from the stream waters; those from the stream sediments; and those from the rice field soil scattered over the area. The dispersion path of the pollution source was also traced. The pH of the hydrologic system ranged from 3.44 to 5.46, which clearly indicates that the area is on the acid environment. The pH tends to rise as the distance from the minehead increases. The content of heavy metal elements dissolved in the stream water varies as follows; Mn=69.73~1.99ppm, Cd=0.02~0.03ppm, Zn=0.77~1.18ppm, Cu=0.04~0.13ppm, Pb=0.22~0.32ppm. The stream water in this state may induce serious heavy metal pollution to the agricultural land and the water for human life especially in the villages down the stream. The content of heavy metal elements dissolved in the stream sediment varies as follows; Mn=245.0~4685.0ppm, Cd=10.0~15.0ppm, Zn=105.0~210.0ppm, Cu=65.0~155.0ppm, Pb=90.0~150.0ppm. The content of heavy metal elements dissolved in the rice field soil varies as follows; Mn=185.0~260.0ppm, Cd=10.0~15.0ppm, Zn=135.0~180.0ppm, Cu=65.0~90.0ppm, Pb=100.0~130.0ppm. The pollution index in the stream sediment and the rice field sell is 1.36~2.03, which shows that pollution had already begun all over the area where the samples were collected.