Generally, vibration absorber systems are composed of spring-mass systems to reduce the vibration of a structure, and there are also methods to simply increase damping to achieve a damping effect across a wide frequency band. One similar method is to use a mechanism in which the eddy current is converted into a mechanical damping effect. When an eddy current is generated by electromotive force due to magnetic flux change, the reaction force is generated by the eddy current’s circulation. In this study, the damping system using the reaction force was constructed to reduce the transmission of vibrations generating from internal fluid and the vibration reduction characteristics that are transmitted externally were analyzed. As a result, 8.2 % of the vibration reduction effect from primary excitation frequency was confirmed.

본 연구에서는 고속수로에서 변위센서를 이용하여 소류력 측정장치를 개발하였다. 최근 강우강도 및 홍수발생빈도의 증가로 제방, 고수부지, 저수로 등의 유실피해가 발생하고 있다. 이와 같은 문제점을 보완하기 위하여 호안블록 등의 다양한 보호공법이 적용되고 있다. 호안공법 및 호안공법 재료의 수리적 안정성 분석을 위해서 소류력에 대한 평가는 필수적이다. 대부분의 소류력 측정은 간접적인 방법으로 유속측정을 통하여 계산되어져 왔다. 하지만 하상유속을 정확히 측정하는 것은 매우 어려운 일이며 평균 소류력을 사용하여 수충부, 비수충부 등 구간별 소류력 분석 등에 대한 구체적인 연구가 미흡한 실정이다. 개발된 소류력 측정장치를 이용하여 공법 및 재료에 대한 정량적이고 객관적인 한계 소류력이 제시되면 하천 피해 절감과 과대 및 과소 설계를 방지 할 것으로 기대된다.

Eddy current separation technique to separate non-ferrous metal particles (Al, Mg, Cu, Sn, Pb, Zn, etc.) and non-metallic particles (plastic, ceramic etc.) of crushed materials of laptop computers was established. As preliminary treatment, laptop computers was shredded and optical sorting machine segregated PCB from Non-PCB. Non-PCB sample was pulverized by cut crusher under the size of 12mm for liberation. Upward flow air separator and magnetic separator were used for eliminated shredding dust, vinyl, paper, and ferrous metal particles from Non-PCB sample. The sample was injected into drum type eddy current separator. Recovery of metals was not enough to separate the sample, the non-conducting part (non-metals part) was repeatedly injected into separator. Recovery of metals increased as the step of repetition, but the cumulative recovery until 4th repetition did not exceeded 65%. However, metal content of non-ferrous metals part (the bounced material) was high and it did not change the grade as the repetition. Therefore, drum type eddy current separator has low recovery in case of small particles but also has the advantage of getting high grade non-ferrous metal.