• 한국기계가공학회지
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• 제17권4호
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• pp.137-142
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• 2018

Recycled synthetic resin materials produced from waste vinyl and waste plastic contain many foreign substances. Plastic products made from this recycled resin materials containing foreign substances are of poor quality, with reduced the strength and rigidity. Foreign substances include heavy metals, cement, foil, dyed paper and dust. In this study, the scratch-Dies process; which remove foreign sbustances, with precision and automation, through a three-stage mesh filter, is designed. The process is evaluated with finite element analysis according to vibration loading and make. After installing the manufactured equipment, recycled resin was producde, and its heavy metal content was evaluated. Recycled synthetic resin materials were also used plastic products and evaluate their strength. In addition, the change in production was assessed.

• 콘크리트학회논문집
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• 제12권5호
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• pp.3-12
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• 2000

Recently, the amount of disposed construction materials like demolished concrete is growing fast and the shortage of natural concrete aggregates is becoming serious. Therefore, recycling of aggregates extracted from the demolished concrete is getting important and use of the recycled aggregates for concrete has been seriously considered. However, the use of the recycled aggregates even for low performance concretes is very limited because there are few rational standard evaluation criteria for recycled aggregates which should be different from that for natural aggregates. In this study, rational evaluation criteria for the recycled aggregates are proposed for their use as concrete aggregates. The study also shows that the performance for both the recycled aggregates and the recycled concrete manufactured with the recycled aggregates can be evaluated effectively according to water absorption ratio of recycled aggregates.

• 한국건설순환자원학회지
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• 제6권1호
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• pp.30-33
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• 2011

• 한국환경과학회지
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• 제10권1호
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• pp.9-12
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• 2001

In this study, development of new sound absorbent which is safety, economical and efficient with using recycled materials is tried for substitution of commercial sound absorbent. The sound absorbents, used in this investigation, were made of used paper or filters of cigarette butts. With the variation of the material densities, sound absorptions of materials were measured. The impedance tube method is used for measuring sound absorption coefficient of the new sound absorbent materials. The measured frequency range was 250Hz to 4000Hz in 1/3 octave band. The sound absorption coefficient of the commercial materials and that of the materials synthesized in the our laboratory show almost same value.

• Computers and Concrete
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• 제19권4호
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• pp.419-427
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• 2017

With the rising global environmental awareness on energy saving and carbon reduction, as well as the environmental transition and natural disasters resulted from the greenhouse effect, waste resources should be efficiently used to save environmental space and achieve environmental protection principle of "sustainable development and recycling". This study used recycled cement mortar and adopted the volumetric method for experimental design, which replaced cement (0%, 10%, 20%, 30%) with recycled materials (fly ash, slag, glass powder) to test compressive strength and ultrasonic pulse velocity (UPV). The hyperbolic function for nonlinear multivariate regression analysis was used to build prediction models, in order to study the effect of different recycled material addition levels (the function of $R_m$(F, S, G) was used and be a representative of the content of recycled materials, such as fly ash, slag and glass) on the compressive strength and UPV of cement mortar. The calculated results are in accordance with laboratory-measured data, which are the mortar compressive strength and UPV of various mix proportions. From the comparison between the prediction analysis values and test results, the coefficient of determination $R^2$ and MAPE (mean absolute percentage error) value of compressive strength are 0.970-0.988 and 5.57-8.84%, respectively. Furthermore, the $R^2$ and MAPE values for UPV are 0.960-0.987 and 1.52-1.74%, respectively. All of the $R^2$ and MAPE values are closely to 1.0 and less than 10%, respectively. Thus, the prediction models established in this study have excellent predictive ability of compressive strength and UPV for recycled materials applied in cement mortar.

• 자원리싸이클링
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• 제30권1호
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• pp.53-59
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• 2021

생활계에서 발생되는 폐비닐은 토사, 금속, 유리 등의 이물질로 인해 고형연료(SRF, Solid Refuse Fuel)로 사용되었지만 최근 환경문제로 인해 고형연료의 사용량이 감소하고 있어 재활용이 필요한 실정이다. 본 연구에서는 폐비닐 재활용을 위해 우선 생활계 폐비닐로 생산된 복합 재생원료와 영농폐비닐로 생산된 PE 단일 재생원료에 대해 분석을 진행하였다. 원료 분석 결과, 폐비닐은 주로 폴리에틸렌으로 이루어져 있고 복합 재생원료는 약 2%의 회분이 잔존하고 있으며 PE 단일 재생원료의 경우는 회분이 없는 것을 확인하였다. 또한 두 재생원료의 배합비율에 따른 인장강도를 측정한 결과 열처리 온도 200 ℃, 압착 압력 30 MPa, 배합비율 3:7 (복합:PE 단일) 조건에서 인장강도가 최대 약 16 MPa임을 확인하였다. 굽힘강도는 열처리 온도 200 ℃, 압착 압력 30 MPa, 배합비율 3:7 (복합:PE 단일) 조건에서 최대 약 39 MPa임을 확인하였다. 따라서 재생원료들의 배합비율에 따른 강도 특성 변화를 확인함으로써 폐비닐의 재활용 가능성을 제시하고자 하였다.

• 한국재료학회지
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• 제13권9호
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• pp.619-624
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• 2003

This paper describes a method to control Mn and Fe contents in recycled AZ91D ingots, based on the mutual solubility of Mn and Fe in AZ91 alloy melts. For this purpose, Fe solubility with the change of Mn content and temperature was investigated in the homogenized and re-precipitated liquid AZ91 alloy. The increase of the amount of Mn added to the melt resulted in the decrease of Fe content. The data obtained in this study was adopted to the pilot plant for recycling of the scrap. As a result, Mn and Fe contents measured in the recycled ingot were in good agreement with ASTM B93 standard.

• Advances in materials Research
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• 제12권2호
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• pp.119-131
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• 2023

The development of sustainable composites materials, from recycled polymeric materials and waste from the wood industry and stone processing, allows reducing the volume of these by-products, minimizing impacts on health and the environment. Nowadays, Polypropylene (PP) is the most recycled polymer in industry, while the furniture industry has increasingly used timber felled from sustainable forest plantations as a eucalypt. The powder tailing from the ornamental stone extraction and processing industry is commonly disposed of in the environment without previous treatment. Thus, the technological option for the development of composite materials presents itself as a sustainable alternative for processing and manufacturing industries, enabling the development of new materials with special technical features. The results showed that powder granite particles may be incorporated into the polypropylene matrix associated with short eucalyptus fibres forming green hybrid composites with potential application in structural engineering, such as transport and civil construction industries.

• 한국건설순환자원학회논문집
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• 제6권4호
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• pp.342-348
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• 2018

이 연구의 목적은 폐필름 포장재 재활용 성형재의 압축, 인장 및 휨 강도와 변형 특성을 생산 공장에 따라 측정하여 건설 2차제품의 적용 타당성을 평가하는 것이다. 재활용 성형재의 역학적 성능은 저밀도 폴리에틸렌 및 고밀도 폴리에틸렌의 일반적 값 수준으로 있지만 성능의 편차를 줄이고 품질의 안정화를 위해서는 1) 구성재료들의 혼합비율에 따른 재료 성능 평가; 2) 이물질 및 수분 함유량에 따른 재료성능 평가; 3) 다양한 제조 조건(제조공정, 가력 압력 및 폐필름 수거지역과 시기)에 대한 재료성능의 데이터베이스 관리 등의 현장 관리 체계마련이 요구되었다.

• Computers and Concrete
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• 제32권4호
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• pp.383-392
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• 2023

The mechanical properties of Recycled Aggregate Concrete (RAC) with 100 percent Recycled Coarse Aggregate (RCA) under loading rates were investigated in depth. The theoretical model was validated utilizing the RAC elastic modulus obtained from cylindrical specimens subjected to various strain rates. Viscoelastic theories have traditionally been used to describe creep and relaxation of viscoelastic materials at low strain rates. In this study, viscoelastic theories were extended to the time domain of high strain rates. The theory proposed was known as reversed viscoelastic theory. Normalized Dirichlet-Prony theory was used as an illustration, and its parameters were determined. Comparing the predicted results to the experimental data revealed a high level of concordance. This methodology demonstrated its ability to characterize the strain rate effect for viscoelastic materials, as well as its applicability for determining not only the elastic modulus for viscoelastic materials, but also their shear and bulk moduli.