• Structural Engineering and Mechanics
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• 제76권5호
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• pp.613-618
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• 2020

Exhausting oil resources and increasing pollution around the world are forcing researchers to look for new, renewable, biodegradable materials to lead sustainable development. The use of fiber reinforced composites based on natural fibres has increasingly begun as prospective materials for various engineering applications in the automotive, rail, construction and aerospace industries. The natural fiber chosen to make the composite material is plant-based fibre, e.g. jute fibre, and hemp fibre. Thermosetting polymer based Epoxy (LY556) was utilized as matrix material and The composites were produced using hand lay-up technique. The fabricated composites were tested for acoustic testing, thermo-gravimetric analysis (TGA) and flammability testing to asses sound absorption, thermal decomposition and fire resistivity of the structures. Hemp fibre composites have shown improved thermal stability over Jute fibre composites. However, the fire resistance characteristics of jute fibre composites are better as compared to hemp fibre composites. The sound absorption coefficient of composites was found to enhance with the increase of frequency.

• 방재기술
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• 통권29호
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• pp.35-38
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• 2000

The apartment houses are increasing for more efficient use of land in our country. Noises form upper story in the silent night makes nervous and uncomfortable. Worst of all, it causes a mental disease. The other side these condition could be a environmental pollution. To prevent like this noise, a variety of sound reducible products are developed and applied in the building construction fields. In this article I' d like to introduce the method of measurement of the impact sound insulation and its practice.

• 소음진동
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• 제6권3호
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• pp.349-355
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• 1996

For a rail traffic noise, a typical source has a length of 200m - 400m so that the noise pollution areas have been located in the transition regions where the sound level drops between 3dB/dd and 6dB/dd. Therefore, in this region, parameters such as a horizontal distance from the track, the geometry of the ground surface, the environmental effect, and the boundary impedance condition play import roles, especially in our nation's situation. In this study, modelling techniques for the finite length of noise source have been investigated in order to evaluate the rail traffic noise level. Then. noise correction value .${\Delta}$SPL for various location in the track region is represented by the non-dimensionalized horizontal and parallel distance from the track. As an application, a high speed train is examined. Beas on the noise data measured for a Eurostar in France, the sound power value per unit length $H_1$is calcuated. It turns out that$H_1$is 109 dB. Overall sound power from the highspeed train to be serviced in our country is expected to 135 dBA.

• 유기물자원화
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• 제5권1호
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• pp.71-85
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• 1997

현재 우리나라에서 휴 폐광된 광산수는 약 500여개가 넘는 것으로 추정되고 있다. 휴 폐광된 광산은 경관의 저해 및 분진발생, 중금속에 의한 토양, 지하수 및 하천오염, 산성광산 배수의 생선, 지반붕괴 등 안전사고의 위험 등의 환경문제를 안고 있다. 국내에서 조사된 일부 휴 폐광된 금속광산의 오염현황을 보면 폐석 방치, 침출수, 갱내수의 유출, 인근 하천 및 토양의 중금속 오염, 시설물의 붕괴위험을 안고 있는 폐광산이 상당히 발견되고 있다. 휴 폐광된 광산의 관리대책으로서는 법규를 정비하여 토양환경보전법에 광산지역의 토양오염기준 복원기준 등이 설정되어야 한다. 또한 광산폐수, 폐기물을 적절히 처리해야 하며 지반침하대책 및 폐광의 지하공간 활용 등에 관한 연구가 진행되어야한다. 이러한 대책을 추진하기 위해서는 무엇보다도 먼저 휴 폐광에 대한 조사가 선행되어야 하며 오염복원순위의 설정, 재원 및 전문인력의 확충이 필요하다.

• 환경위생공학
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• 제7권2호
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• pp.53-68
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• 1992

Since 1962, Korea has made a remarkable progress with continuous success of Five-Year Economic Development Plans. Over the last 30 years, Korea has achieved a fast growth in various industries including heavy industry and chemical industry with rapid urbanization at the same time. The fast industrialization and urbanization brought about huge amount of hazardous/toxic substances and wastes. The environmental pollution problems have now emerged from regional concerns to overall social issues accordingly. The situation has come to a point where pollution control and environment preservation have become one of the nation's major policies. Following the recent Earth Summit of UNCED Conference held in Riode Janeiro in June 1992, where the topic was environmentally sound and sustainable development, awareness upon the importance of environmental preservation has been heightened globally, The environmental issues will gradually influence the international society more and more, politically as well as economically, The environmental pollution control industry in Korea started in the early 70's with the development of the nation's industrialization, As the people's awareness on pollution increases and environmental laws and enforcing regulations were established, demand for pollution control began to increase. The environmental pollution control business came to be recognized as an independent industry in the mid'70's. It should be evaluated properly that over the last 30 years, the Korean pollution control industry has supplied locally manufactured pollution control facilities to the increasing local demand. Concerning the quality and customer satisfaction, however, there are still many aspects which need to be improved compared with those of advanced countries. Although the start of the pollution control industry in Korea is just 10 to 15 years behind the advanced countries such as Japan and European countries, current gap in the environmental technology is rather considerable. And, studies should be made to find out the reasons for the current technology gap, and therefore, to implement solutions to improve the technology and competitiveness of the environmental pollution control industry in Korea.

• International Journal of Internet, Broadcasting and Communication
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• 제9권2호
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• pp.37-41
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• 2017

In the development of means of transportation, human beings who walk, ride or ride carriages are now enjoying the benefits of many means of transportation, including bicycles, airplanes, trains, buses, and cars. In the case of automobiles among various means of transportation, there is an advantage that an individual can conveniently move while possessing it. To solve air polution problems at the same time, eco-friendly automobiles such as low-noise, low-pollution, and high-efficiency automobiles have emerged. However, in the case of eco-friendly vehicleJ, engine noise at low speeds is a noise that is unlike existing vehicles and poses a threat to the safety of pedestrians. In this study, virtual engine system has been developed to prevent engine accidents caused by low- The pedestrians are aware of the fact that the vehicle is approaching.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1473-1478
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• 2000

Severe fork-lift truck noise is annoying to an operator as well as one of the noise pollution elements. This paper presents the noise contribution analysis of a cabin type fork-lift truck to identify the major sources and its usage to reduce the interior noise level. The methodologies for this work are sound field analysis, sound intensity test, insertion loss test of duct system and etc. An effective method to suppress interior noise level of fork-lift truck and design guides are suggested.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1998년도 춘계학술발표회 논문집
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• pp.156-162
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• 1998

The whistle is a very important information source for the safety navigation under foggy weather. But navigator has no concern about this , because it must be achieved by human hearing sense and considered as a vague signal. If the range and relative bearing of signa source can be detected automatically, it would be very useful system for preventing marine casualties making a lot of economic loss and environment pollution. Before the algorithm of 2-dimensinal sound source tracking system was reported . This paper describes the method that can obtain thetime lag between three signas and the theory of cross-correlation analysis and subtraction method for cauculating the time lag by using the digital signal data sequences. And a series of experiments were carried out for various position of sound source in the range from 200m to 530cm.

• 한국해양공학회지
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• 제17권2호
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• pp.8-13
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• 2003

Soil, ground water, and sea bed are exposed to a continuous accumulation of polluted materials, causing serious environmental damage. It has been reported that such pollution causes a massive mortality of fish stock in rivers due to the resuspension of toxic chemicals, occurring during strong wind conditions. Therefore, it becomes apparent that there is an immediate demand for the restoration treatment of polluted river bed (or sea bed) sediment layers. Pollution levels of major rivers and ports, such as Paldang, Kyungan rivers, and Masan port, are becoming of great public concern, and are posing a serious environmental threat. In particular, the pollution of the Shi-hwa river has become a nation wide issue for the last few years. In spite of such public concern, the pollution levels of such rivers or ports are worsening everyday. In this study, an environmentally sound engineering package is introduced that helps to restore the polluted river bed or sea bed sediments. This engineering package consists of a suction facility, followed by a series of mechanical, chemical, and biological treatment units. The suction facility is designed to minimize secondary pollution that occurs from the resuspension of toxic materials during suction. The sea bed cleaning engineering package is designed to be installed on the top of a floating barge. Such a combination of environmental plant and shipbuilding technology provides a cost-effective solution, minimizing the transportation between suction and treatment facilities.

• 기술사
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• 제33권5호
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• pp.16-22
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• 2000

The rapid industrializing of China has helped the development of the industrial economy since 1980. However, the problem is some environmental pollution, such as SO$_2$, TSP, HOx, Dioxin etc, generated by the industrial facilities located in Northeastern China is moving to the Korean Peninsula through the cold air stream during the Asian dust season, This kind of air pollution worsens the environmental pollution of the Korean Peninsula year by year. Therefore, NGO suggests to China that the minimization of the environmental problems linked to both Korea and China has to be discussed. In fact, I would like to suggest that the activity of EMS(ISO14000) should help the environmentally sound '||'&'||' sustainnable development of both countries,