• 한국건축시공학회지
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• 제14권1호
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• pp.54-60
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• 2014

The purpose of this study is to examine whether cementitious powder separated from waste concrete can be used as an alternative raw material to limestone and reduce the usage of natural resource (limestone) and $CO_2$ emission based on recycling cementitious powder from waste concrete. Experiments actually analyzed the chemical composition of cementitious powder and performed hyperthermia analysis, measurement of free CaO and XRD analysis to measure the degree of recovery of hydration in the model of cementitious powder manufactured based on chemical composition. These were performed in each cementitious powder model at different calcination temperatures such as $900^{\circ}C$, $1200^{\circ}C$, $1300^{\circ}C$, $1400^{\circ}C$ and $1450^{\circ}C$. Through the experiments, it was found that the recovery of hydration was at a level which can be used as the alternative raw material for limestone, but the replacement ratio was directly affected by the degree of mixing of fine aggregate in less than $150{\mu}m$, which cannot be separated from cementitious powder. It was shown that there was no difference in the production of compounds involved in hydration at calcination temperatures of $1200^{\circ}C$ or higher. Therefore, to pursue the replacement of limestone and reduction of greenhouse gas by recycling cementitious powder, the development of technology to efficiently separate aggregate fine powder is required.

• 유기물자원화
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• 제21권1호
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• pp.76-84
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• 2013

본 연구에서는 RDF와 목재펠릿 그리고 폐목재, 폐섬유, 폐비닐 각각 폐기물로 반응속도를 분석하기 위해 열중량 감량 분석, 비등온 실험, 삼성분, 화학적 조성 분석, 발열량, 활성화 에너지(E) 기울기를 실험하고 값을 구하였다.고형연료의 각각의 삼성분을 비교하였을 때 RDF가 목재펠릿 보다 수분함량이 적게 나왔으며 발열량을 통해 각각의 폐기물 고형연료에서 연소반응 속도을 비교하여 보면 폐비닐의 연소반응이 제일 크게 나타났다. RDF와 목재펠릿을 비교해보면 회분의 차이는 목재펠릿이 좋다는 것을 알 수 있지만 활성화에너지로 비교하게 되면 RDF의 효율이 다른 4가지의 연료보다 좋다는 것을 알 수 있다. RDF는 승온 속도에 따라 차이가 있지만, $320{\sim}720^{\circ}C$ 사이에서 반응이 일어나는 것을 확인 할 수 있다.

• 유기물자원화
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• 제16권3호
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• pp.65-74
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• 2008

본 연구에서는 서로다른 4지역의 도시 생활 쓰레기의 성상 및 물리 화학적 조성을 조사 하였다. 생활 쓰레기 연료화시설 설치 및 자료확보 차원 매립장 관리차원에서 매우 필요한 연구이다. 평균 밀도는 $79{\sim}199.8kg/m^3$ 범위내의 결과를 얻었다. 생활 쓰레기는 8.87%의 음식물류, 38.8%의 종이류, 34.12%의 플라스틱류 및 비닐류, 7.16%의 섬유류, 0.96%의 목재류 1.3%의 고무 및 가죽류 등으로 구성되어 있다. 생활쓰레기의 대부분은 음식물, 종이류, 플라스틱류 등으로 이루어져 있으며 94% 정도가 가연 성분이다. 삼성분 분석에서는 17.38%의 수분 및 69.03%의 가연분 그리고 6.24%의 회분으로 이루어져 있다. 원소분석결과는 탄소 산소 수소 순으로 이루어져 있다. 생활쓰레기의 저위 발열량은 2973.8kcal/kg 이며 고위 발열량은 5209.94 kcal/kg 결과를 얻었다.

• 한국축산시설환경학회지
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• 제19권1호
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• pp.39-46
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• 2013

This study was carried out to compare the filtration effect of anaerobic digestion waste water by compost filtration bed. Three types of filtration systems were set for filtration test following to composition of bedding materials. Two filtration systems were filled with sawdust, rice-hull and wood-chip. And the other was filled with sawdust and rice-hull. Anaerobic digestion waste water was applied evenly on the surface of the filtration bed with spraying nozzle. The concentration of nitrogen, biochemical oxygen demand (BOD), suspended solids (SS) of anaerobic digestion waste water was decreased by filtration treatment. The total nitrogen content was decreased from 1,313 mg/L to 1,090~1,293 mg/L and BOD concentration was decreased from 529.7 mg/L to 125~162.3 mg/L, respectively. The SS content was decreased from 69~79% by filtration process. In addition, the electrical conductivity (EC) was decreased from 10.22 ds/m to 7.91~8.31 ds/m.

• 자원리싸이클링
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• 제12권4호
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• pp.51-57
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• 2003

케퍼시터용 Ta 분말제조공정에서 발생하는 waste 분말을 이용하여 TaC 분말을 자전고온합성법에 의하여 합성하였다. waste TA는 합성반응의 활성 및 산화방지를 위하여 전처리공정에서 미분쇄 및 탈산처리가 필요하였다. 합성반응에서는 TaC 단일상은 6∼7wt.％C의 조성범위에서 얻을 수 있었다. 또한 반응온도는 시료의 압축력에 영향을 받으며, 압축력 1600psi에서 최고반응온도를 나타냈다.

• 자원리싸이클링
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• 제12권1호
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• pp.18-24
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• 2003

무전해 Ni-Cu-B 폐 도금액의 재사용에 대해 소정의 조건에서 조사하였다. 아연화처리한 후 니켈 촉매의 처리는 니켈 촉매처리를 하지 않았을 때 보다 도금시간이 연장되었다. Batch type에서 새로 제조한 도금액에 폐 도금액을 40% 첨가하여도 무전해 Ni-Cu-B 폐 도금액의 재사용이 가능하였다. 새로 제조한 도금액에 소모된 도금액의 성분을 연속적으로 보충하여 도금하면(continuous type), 보충하지 않았을 경우(batch type) 보다 도금시간이 6배 연장되었다. 새로 제조한 도금액에 폐 도금액 40%를 첨가하여 소모된 도금 액의 성분을 연속적으로 보충할 경우(continuous type)의 도금시간은 보충하지 않았을 경우(continuous type)의 도금시간 보다 2배 연장되었다. 도금층의 불량과 급격한 도금속도의 감소는 도금층의 Ni과 Cu의 성분 변화에 큰 영향을 미쳤다.

• Advances in environmental research
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• 제3권4호
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• pp.337-353
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• 2014

The determination of the effectiveness of the immobilization of blasting dust (waste generated in galvanic activities) in cement matrix, as well of mechanical, physical and microstructural properties of concrete paving blocks produced with partial replacement of cement was the objective of this work. The results showed that blasting dust has high percentage of silica in the composition and very fine particle size, characteristics that qualify it for replacement of cement in manufacturing concrete blocks. The replacement of Portland cement by up to 5% residues did not cause a significant loss in compressive strength nor increase in water absorption of the blocks. Chemical tests indicated that there is no problem of leaching or solubilization of contaminants to the environment during the useful life of the concrete blocks, since the solidification/stabilization process led to the immobilization of waste in the cement mass. Therefore, the use of blasting dust in the manufacture of concrete paving blocks is promising, thus being not only an alternative for proper disposal of such waste as well as a possibility of saving raw materials used in the construction industry.

• 방사성폐기물학회지
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• 제19권2호
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• pp.197-204
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• 2021

In this study, the well-known non-destructive acoustic emission (AE) and electrical resistivity methods were employed to predict quantitative damage in the silo structure of the Wolsong Low and Intermediate Level Radioactive Waste Disposal Center (WLDC), Gyeongju, South Korea. Brazilian tensile test was conducted with a fully saturated specimen with a composition identical to that of the WLDC silo concrete. Bi-axial strain gauges, AE sensors, and electrodes were attached to the surface of the specimen to monitor changes. Both the AE hit and electrical resistance values helped in the anticipation of imminent specimen failure, which was further confirmed using a strain gauge. The quantitative damage (or damage variable) was defined according to the AE hits and electrical resistance and analyzed with stress ratio variations. Approximately 75% of the damage occurred when the stress ratio exceeded 0.5. Quantitative damage from AE hits and electrical resistance showed a good correlation (R = 0.988, RMSE = 0.044). This implies that AE and electrical resistivity can be complementarily used for damage assessment of the structure. In future, damage to dry and heated specimens will be examined using AE hits and electrical resistance, and the results will be compared with those from this study.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.544-549
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• 2009

Alongside the increasingly larger domestic construction projects is the gradual rise in construction waste. Consequently, serious environmental problems emerge. The increase in demand for housing remodeling due mainly to the increase in national income and improvement of quality of life is the main reason for the increase in construction waste. This study was conducted as the basic study for the prevention and reduction of construction waste generated by apartment remodeling; it aimed at identifying the remodeling items and reasons. Toward this end, this study targeted apartments at least 15 years old and conducted a questionnaire survey to determine the remodeled sections and remodeling reasons. As a result of the questionnaire survey, the bathroom, floor finishing, and kitchen furniture recorded the highest ratios in remodeling. Old materials, aesthetic motivation, and pleasant living space composition were cited as the major remodeling reasons. This study is significant as a basic study for generating environmental and economic profits through systematic waste management. Further studies should develop guidelines suitable for construction waste reduction and recycling in line with the construction and demolition phases in case of remodeling.

• 유기물자원화
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• 제16권4호
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• pp.74-81
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• 2008

현재 전국 대형생활폐기물 소각시설은 음식물류폐기물 분리배출로 인하여 반입폐기물의 가연분 함량은 증가하고 수분 함량은 감소하는 성상의 변화를 보이고 있다. 이러한 폐기물 성상의 변화는 반입폐기물의 발열량을 증가시켜 소각시설의 수명 단축 및 가동률을 저하시키는 문제를 발생시키고 있다. 따라서 본 연구는 인천광역시의 점증하는 생활폐기물에 대한 효율적인 소각시설운영방안을 제안하기 위한 연구로써 인천광역시 생활폐기물의 성상변화가 소각시설에 미치는 문제점과 음식물류폐기물 혼합소각에 의한 발열량 관리방안에 대하여 검토하였다. 그 결과 음식물류폐기물과 생활폐기물의 혼합소각은 폐기물의 발열량이 지속적으로 상승하고 있는 추세를 감안할 때 발열량의 저감 역할을 함으로써 소각시설의 적정운영과 동시에 음식물류폐기물의 처리비용을 절감 할 수 있는 경제적 효과를 기대할 수 있을 것으로 판단된다.