Accurate and effective powder compaction analyses are performed for brittle materials such as graphite, utilized as a solid lubricant, by using the discrete element method (DEM). The reliability of the DEM analysis is confirmed by comparing the results of graphite powder compaction analyses using the DEM particle bonding contact model and particle non-bonding contact model with those from the powder compaction experiment under the same conditions. To improve the characteristics, the parameters influencing the compaction properties of the metal-graphite mixtures are explored. The compressibility increases as the size distribution of the graphite powder increases, where the shape of the graphite particles is uniform. The improved compaction characteristics of the metal-graphite (bonding model) mixtures are further verified by the stress transmission and compressive force distribution between the top and bottom punches. It is confirmed that the application of graphite (bonding model) powders resulted in improved stress transmission and compressive force distribution of 24% and 85%, respectively.

In this paper, a durability study is presented to enhance the mechanical properties of an Fe-Si-Al powderbased magnetic core, through the addition of graphite. The compressive properties of Fe-Si-Al-graphite powder mixtures are explored using discrete element method (DEM), and a powder compaction experiment is performed under identical conditions to verify the reliability of the DEM analysis. Important parameters for powder compaction of Fe-Si-Algraphite powder mixtures are identified. The compressibility of the powders is observed to increase as the amount of graphite mixture increases and as the size of the graphite powders decreases. In addition, the compaction properties of the Fe-Si-Al-graphite powder mixtures are further explored by analyzing the transmissibility of stress between the top and bottom punches as well as the distribution of the compressive force. The application of graphite powders is confirmed to result in improved stress transmission and compressive force distribution, by 24% and 51%, respectively.

Since the 1990s, waste policies of the South Korean government have focused on resource recycling societies that reduce the amount of waste landfill and increase the amount of waste recycling. In South Korea, the implementation of various environmental policies and efforts has led to the highest recycling rate in the world; however, after 2011, the recycling rate of household waste has been stagnant. Therefore, to convert such waste disposal problems into a resource recycling socioeconomic regime conforming to the national policy, establishing a tool to evaluate the appropriate management policy of household waste is necessary. In this study, a waste management evaluation index was developed and applied to identify and evaluate trends in the waste disposal methods. For the evaluation index, we considered two points of evaluation, i.e., “waste recycling increases and waste landfill decreases” and “the current waste recycling rate is taken into consideration.”. The data of waste disposal of 2007, 2012 and 2015 in 16 municipalities was used. The results shows that the highest absolute index was (+)28 in Chungbuk, whereas the lowest was analyzed as (-)10 in Daegu. Moreover, the cities with high recycling rates and low landfill rates were Seoul and Busan, while Jeonnam had the low recycling rate and the high landfill rate. Furthermore, Chungnam and Chungbuk were very likely to develop further, whereas Daegu and Incheon had a very low possibility of development. This waste management evaluation index and method can be one important tool and approach and can support more sustainable and resource recycling socioeconomic.

인구 증가와 인구의 도시 집중 발생, 이에 따른 도시의 변화와 생활양식의 변화 등은 자연환경에 끊임없는 부담을 가중시켜 환경문제를 발생시키고 있다. 현대 산업사회의 대량생산, 대량소비 등으로 인한 폐기물 문제는 심각한 사회문제로 대두되고 있다. 이에 발생량이 증가하면서 폐기물문제는 사회적 이슈로 등장하게 되었다. 이러한 문제가 대두됨에 따라 스위스 제네바의 연방 폐기물 정책은 미래의 재활용을 위해 가정용 폐기물을 분류하는데 초점을 맞춤으로써 자원 보호의 목적을 달성하게 되었다. 연방 및 시의 권위자는 각 가정들의 폐기물 분류를 향상시키기 위하여 강화된 정책기구 또는 사회기반시설을 바탕으로 하는 기구들, 그리고 설득력 있는 기구들을 이용하여 제네바에서 2002년부터 2013년까지의 가정용 폐기물을 분류하고, 재사용하는 정책에 대해 평가와 현 상황의 분석을 함께 진행하였다. 정책 평가의 결과는 소각세 등 강화된 기구들이 제네바 자치당국의 분류 시스템 및 사회기반시설들이 효율적으로 향상되는 것을 보여준다. 아직 이러한 연구가 미흡한 우리나라 가정생활폐기물에 대해 제네바의 선행연구를 바탕으로 폐기물흐름분석과 향후의 각 도시별 트랜드를 예측하는 지표를 개발함으로서 가정계 생활폐기물의 적정관리 방안 마련을 위한 기초자료로 활용하기 위해 연구를 진행하였다.