• 한국환경보건학회지
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• 제46권6호
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• pp.646-654
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• 2020

Objectives: Users of parks or children's play facilities have pointed to pets' bowel movements as the most serious problem when using them. In prior studies, a very low detection rate of parasites (eggs) in sand flooring materials has been found. Even though feces have been identified, no parasites (eggs) have been detected. Method: A standard solution of nitrate nitrogen was used to verify the reliability of a new nitrogen analysis method. The linearity, precision, and accuracy of the nitrate nitrogen analysis method were verified. Using this method, the pollution distribution of the sand flooring material and the degree of pollution at each point were investigated. Results: As a result of the verification of the nitrogen analysis method, the linearity was found to be good at r2=0.999 when distilled water is mixed in a standard substance solution. The standard substance additive solution r2=0.968 was found to be good. Precision represented 0.01 to 0.06% RSD for peak height. The recovery rate was 92.4 to 104.0 percent, indicating high accuracy. According to the same method of analysis, the flooring material sand at a general amusement facility with the largest number of concealed spaces was nitrate nitrogen 6.1 times higher than at the entrance of the playground. Also, in a comparison between clean sand and sandy flooring, the average nitrogen concentration of the sand flooring material was 24.4-167 times higher than pure sand. Conclusions: As such, no parasites (eggs) were detected at all points under investigation, but the sand flooring was exposed to animal fecal contamination. Therefore, the management of nitrogenous components should allow accurate identification of animal fecal contamination so that the timing of sand replacement can be managed hygienically and safely.

• 한국건설순환자원학회논문집
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• 제10권3호
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• pp.327-334
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• 2022

이 연구에서는 목재칩 열병합발전소 바닥재를 잔골재로 활용한 모르타르 및 콘크리트 특성을 평가하고자 부순 잔골재 대용으로서 목재칩 골재대체율과 물시멘트비에 따른 모르타르 특성과 목재칩 골재대체율에 따른 콘크리트의 특성을 비교 및 평가하였다. 목재칩 골재 대체율에 따른 시멘트 모르타르의 플로우는 목재칩 골재 대체율이 높아질수록 증가하는 경향을 보이고, 압축강도와 휨강도는 목재칩 골재 대체율이 높아질수록 증가하였다. 콘크리트의 슬럼프와 공기량은 골재 대체율이 높아질수록 증가하고, 콘크리트의 압축강도와 인장강도는 목재칩 골재 대체율이 증가할수록 높은 경향을 보였다. 이에, 열병합발전소로 인하여 발생하는 바닥재를 콘크리트용 잔골재로 활용하는 방안의 가능성을 확인하였다.

• Advances in nano research
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• 제14권1호
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• pp.81-92
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• 2023

In this work, the effect of the addition of Aerosil 200, an insulating resin applied in many industries, on the water absorption of cement plast mixture has been experimentally evaluated. First, the preparation stages of cement plast mixture was evaluated based on corresponding standards and then, the effect of the addition of Aerosil 200 nanoparticles (NPs) to cement plast mixtures with sand weight percentage range of 0-0.1% on the variation of water absorption properties was evaluated based on National Standard Institution of Iran 20185 for Concrete Flooring Blocks - Requirements and Test Procedures. Based on the obtained results, it could be found that excessive addition of NPs did not affect the physical properties of the final product. Water absorption percentage was increased in the weight percentage of cement. By the increase of the amount of Aerosil 200 NPs in the prepared cement plast mixture, the percentage of water absorption in weight percentage of sand was decreased. Cement plast with NPs presented significantly lower water absorption than that without NPs.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.141-142
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• 2015

This literature study is focused on the improvement of lightweight concrete in perspective of foaming agent. Lightweight concrete is the cured concrete as putting required amount of foaming agent to slurry which is a mixture of a certain amount of cement, sand, and water. It has lower density than general concrete, because foaming agent disintegrates numerous bubbles evenly and independently. Thus, it is capable of lightening the weight and great for sound absorption and insulation, In foreign countries, studies for structural lightweight concrete mainly of tunnel grouting and weight lightening of heavy structures are going along actively. Domestically, exterior panel and ALC blocks are alternatively used for flooring. Therefore, this research consider improvement of lightweight concrete in perspective of foaming agent with foundation study.

• 환경영향평가
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• 제32권5호
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• pp.269-278
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• 2023

서울 도심에 있는 어린이 모래 놀이터의 안전한 사용을 확인하기 위해 토양 중금속(Cd, Cu, As, Pb, Zn, Ni, Hg, Cr⁶⁺) 오염현황을 조사하였다. 시료 채취 장소는 서울시 7개 자치구에서 281개소를 선정하였다. 본 연구에서 중금속의 전체 평균 농도는 Cd 0.21 mg/kg, Cu 5.97 mg/kg, As 2.40 mg/kg, Pb 7.55 mg/kg, Zn 34.08 mg/kg, Ni 4.22 mg/kg, Hg 0.02 mg/kg였다. Cr⁶⁺은 불검출되어, 이를 포함하는 중금속 7종 모두 토양오염우려기준 1 지역 기준보다 낮은 것으로 나타났다. 아울러 토양오염등급(SPC)을 평균값으로 평가했을 경우에 7개 자치구 모든 지점에서 1등급인 100 미만인 것으로 나타나 건전한 토양 상태임을 보였다. 하지만 최대값으로 평가했을 경우 5개 자치구에서 일부 100 이상의 값을 나타내었다. 따라서 안전한 토양환경을 위하여 어린이 놀이터의 관리주체인 지자체의 지속적인 관리와 관심이 필요한 것으로 보인다.