• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.233-238
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• 2003

Several types of gamma-ray sensors were constructed by packing different numbers of fibers into aluminum tubes, and tested to detect the $^137Cs$ gamma ray. It has been found from this investigation that tapered fibers can be more efficient to collect the lights produced inside the sensor and transfer them into the transmitting fiber in order to predict the functioning of the tapered fiber, tapered plastic scintillators, composed of polystyrene with minute amount of dPOPOP and PPO or dPBD, were fabricated and tested for the detection of gamma rays from 1.0 1.5 3.0 5.0 ${\mu}Ci$ $^137Cs$ sources, and the pulse hight spectrum and the relationship between the radioactivity and the total counts are analyzed. It has been found from this study that the tapered scintillating optical fiber, if manufactured, can be practically applied to the development of gamma-ray sensors which can be deployed In ${\mu}Ci$-level radiation fields

• Resources Recycling
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• v.27 no.4
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• pp.3-15
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• 2018

Since the use of plastics in various goods such as film, containers, and packaging has been increasing in Korea, the generation of plastic waste is increasing. Plastic wastes are managed by waste charge system, Extended Producer Responsibility (EPR) system and voluntary agreement of plastic waste collection-recycling system. Recently, the management of plastic waste is becoming a social issues due to the refusal of the collection of plastic waste including waste plastic bag and waste vinyl. The ministry of environment in korea was set up the comprehensive plan for recycling waste management in accordance with the circulation cycle of manufacturing and production - distribution and consumption - separate and discharge - collection and sorting - recycling. In this study, the improvements for management of plastic waste were suggested with the review of domestic waste plastics management and the comprehensive plan by the ministry of environment.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.3
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• pp.159-165
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• 2005

The characterization of radiological contamination inside pipes generated during the decommission of a nuclear facility is necessary before pipes can be recycled or disposed. But, existing direct measurements of radioactive contamination level using the survey-meter can not estimate the characteristic of contamination on a local area such as the pipe inside. Moreover, the measurement of surface contamination level using the indirect methods has many problems of an application because of the difficulty of collecting sample and contamination possibility of a worker when collecting sample. In this work, plastic scintillator was simulated by using Monte Carlo simulation method for detection of beta radiation emitted from internal surfaces of small diameter pipe. Simulation results predicted the optimum thickness and geometry of plastic scintillator at which energy absorption for beta radiation was maximized. In addition, the problem of scintillator processing and transferring the detector into the pipe inside was considered when fabricating the plastic detector on the basis of simulation results. The characteristic of detector fabricated was also estimated. As a result, it was confirmed that detector capability was suitable for the measurement of contamination level. Also, the development of a detector for estimating the radiological characteristic of contamination on a local area such as the pipe inside was proven to be feasible.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.1
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• pp.70-78
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• 2008

In this study, the composition and physico-chemical characteristics of school waste which is located in B area, kyunggi-do was investigated. It is necessary to measure the characteristics of school waste to build the data-base for resource and recycling of waste. This school waste was composed of 12.25% of food wastes, 56.26% of papers, 9.26% of plastics&vinyls, 1.52% of textiles, 3.70% of wood, 0.11% of rubbers&leathers and others, respectively. Most of school wastes are mainly composed of paper and plastic waste and composition of combustible waste was about as 90%. From 3-components analysis, contents of moisture, combustible component, and ash was 5.72%, 88.29% and 5.98%, respectively. Moisture content was higher in Agricultural Dwelling school area compare to the urban dwelling school area. The chemical element of the school waste has the high order of carbon, oxygen, hydrogen on the dry basis of wastes and the low heating value of the MSW which is measured by calorimeter is shown as 3720.44kcal/kg.

• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.125-137
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• 2023

In marine environments, plastics have become more abundant due to increasing plastic use. Especially, in coastal regions, particles may remain for a long time, and they interact with flows, wind, sand and human activities. This study aimed thus to observe how plastic debris interacts with and escape from sediments. A series of experiments were conducted in order to gain a better understanding of particle release from coastal sediments into water body. An oscillating water tunnel was built for the experiments, and used to generate oscillatory flows of relatively high Reynolds number and induce sediment transport. Spherical plastic particles of three different sizes was used in lieu of plastic debris in environments. It was observed that release of the particles was directly related to change of bedform, which is in turn determined by the flow condition. Also smaller particles tend to escape the sediment more readily. Critical values for dimensionless parameters are proposed.

• Resources Recycling
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• v.6 no.2
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• pp.47-59
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• 1997

Thc paper points oul ever increasing amounts of plastics used in dex, clopmg countries and the prohlelns associated with such increase. Tl~e current status of the production and usc of plaslic materials is reviewed. Also reviewed lncludc thc pahcicies and gu~dclmcs canccrning the treatment of used plastics which have already bccn mstitutcd.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.245-246
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• 2000

산업의 발달로 인하여 유해폐기물의 양과 종류가 날로 증가하고 있다. 특히 본 연구에서 사용한 $CCl_4$는 염화탄화수소(chlorinated hydrocarbons, CHCs)(Elizabeth 와 Catherine) 계통의 대표적인 유해폐기물이며 플라스틱제조업, 제초제와 살충제를 제조하는 농약제조업, 유기용제 제조업 등에서 다량 배출되며 해마다 발생량이 증가하는 추세이다. 최근까지 대부분의 유해폐기물을 처리가격의 저렴성과 기술적으로 어려움이 적은 매립 및 밀봉등의 방법과 물리화학적 방법으로 처리하였으나 앞으로는 소각에 의한 처리방법이 증가되리라 예상된다. (중략)

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.218-218
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• 2021

최근 환경 문제과 관련하여 건설 분야에서 발생하는 환경적인 부담을 줄이고자 다양한 재활용 소재들에 대한 연구에 대한 관심이 증가하고 있다. 특히 폐기물 중 생활계에서 발생하는 폐플라스틱은 '쓰레기 대란'이라는 사회적 문제로 대두된 사례가 있다. 생활계에서 발생하는 폐비닐은 다양한 조성으로 이루어져 재활용 대상에서 제외되기 때문에 매립 또는 소각되는 플라스틱의 양을 줄이고 재활용율을 늘릴 수 있는 연구가 필요하다. 본 연구는 생활계에서 발생하는 폐비닐을 융용시켜 무기첨가제 등을 한 복합 Alloy를 생산한다. 또한 재생이 가능한 복합 Alloy를 압출 또는 사출 과정을 통해 테트라포드의 형태를 만들 수 있는 Preform으로 가공하는 공정연구 하였으며 이러한 Preform을 해안 및 항만에서 사용되는 콘크리트 피복재에 적용하였을 때 플라스틱 소재와 콘크리트 소재의 비중의 차이로 인해 발생하는 안정성을 정량적으로 평가하는 수리모형 실험를 수행하였다.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.3
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• pp.74-81
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• 2013

In this study, the separation efficiency of wind power selector (the direction of the air flow of the air to perform gravity separation method) of municipal solid waste which was landfilled was investigated to reduce amount of waste that is designed to increase the recycling rate of wastes for the ANSYS CFX Program's numerical methods with wind through the separator. When a suction device designed to suction 1000mL of a plastic bag, the separation efficiency was 100% and when the wind speed was 0.9 m /sec or more and when the wind speed was 1.6 m / sec or more, the efficiency of plastic bottles in a mixture of 500mL and 1500mL plastic bottle waste was 100% and the aluminum screening efficiency of 250mL aluminum can was 100 % when the wind speed was 2.3 m / sec. In the last, 5mm thick compressed aluminum can efficiency was 90 % when the wind speed was 2.4 m / sec.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.220-226
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• 2005

This study evaluated the composition and distribution of marine litters on the sea-bed of the East China Sea. Surveys have been conducted by a benthic trawlnet of Dong-baek training ship of Yosu national university during the cruise of 2002-2004. Distribution density showed high value in C5 (north-western area of Jeju Island) with $110.3kg/km^2$ and those of annual mean were about $31-43kg/km^2$. Fishing gears such as nets, pots, octopus jars and etc. were about 42-72% of debris collected in the East China Sea. Composition ratio of rubber, vinyl. metal, plastic, glass, wood, cloth and etc. were within 25% except C5. Rope and drum showed strong fluctuations with 0-30% according to the trawling sites. Some vinyls and nets made in Korea, China and Japan were much collected. It is estimated that fishing gears were discarded to the sea by fishing operation, deliberately or not. An comprehensive program including continuous research, monitoring for marine litters in the Korean sea were necessary.