The characteristics of stress distribution and fatigue life have been investigated in the road mower head system using FEM(Finite Element Method). There is high stress distribution around the coupling part with non-uniform load from the irregular road surface. Maximum equivalent stress especially occurs in the fixed plate and the pillar of the head device with maximum deformation at the rotation axis frame of the mower system. Fatigue life tests were also performed with SAE bracket history, SAE transmission, and sample history conditions. SAE bracket history and SAE transmission predicted the possibility of high damage while Sample history showed a stable trend. These results will be applicable in optimal design for various systems equipped with mower head system.

As the Enforcement Ordinance of Environmental Policy Act was revised in 2013, total organic carbon(TOC) was added as an indicative parameter for organic matter in Water and Aquatic Ecosystem Environmental Criteria. Under these imminent circumstances, a regulatory standard is needed to achieve the proposed TOC limitation control water quality from the public sewage treatment plants(PSTWs). This study purposes to present the determination method for TOC effluent limitation at the PSTWs. Therefore we investigate the TOC effluent limitation of foreign countries such as EU, Germany and USA, and analyse the effluent water qualities of PSTWs. In using these TOC data, we review apprehensively the statistics-based, the technology-based, and the region(water quality)-based determination method of TOC effluent limitation for PSTWs.

In this study, natural frequency characteristics of road mower head system are investigated through experiment and numerical analysis. ANSYS workbench 14.5 is used to calculate the frequency analysis in the mower system. Compared the natural frequency using the modal test and computerized analysis. When compared with the experimental results, a 5% error rate has occurred. Simulation results showed that vibration mode shape has directional characteristics, especially to the right and left. These results will be helpful in optimal design for road mower head systems.

Seawater flow characteristics around deep-sea sediment resuspension system was analyzed using CFD simulation. Seawater flow is influenced by migration velocity of DSSRS and the resuspension system with disturbance device. Especially complicated flow field is generated with discharged flow in the vertical direction, and there is large variation of seawater velocity near the system with vortex flow. Turbulent kinetic energy near the system increases 2～6 times, and its variation is also affected by the operation condition of the disturbance device. The results of this study are expected to be useful in evaluating the environmental effects of the suspended solid matters which are generated in the deep sea sediment disturbance process.

Numerical analysis was performed to analysis the structural characteristics of the head device in the road mower system. The head device connects mower system with the boom of the special vehicle. The system with various road surface conditions is subjected to continuous vibration and repeated load. Especially, the maximum equivalent stress occurs in the pillar of the head device, and the maximum equivalent strain also occurs in the fixed plate that supports the mower system. Fatigue analysis results show that the upper end of the pillar is very vulnerable. This analysis results can be used as basic data for optimal road mower head system design.

본 연구에서는 파이로프로세싱에서 발생하는 배기체 내 요오드 포집을 위한 매질로서 고가의 은 기반 흡착제를 대체하기 위 한 상용 구리메쉬의 가능성에 대해 연구하였다. 열역학적 계산을 통해 구리 금속과 요오드 기체의 반응은 100 ~ 500℃ 온도 범위에서 자발적으로 일어나며 요오드화구리(CuI)를 형성할 것으로 예상되었다. 실험을 통해 반응 온도에 따른 요오드 포 집 효율의 영향을 분석한 결과, 1개의 구리메쉬(질량 0.26 g)를 이용하여 반응 온도를 300, 400℃로 변화하였을 때 각각 5 및 6 wt%의 요오드(초기질량 2.0 g)가 포집됨을 확인하였다. 또한, 반복 실험 결과를 토대로 구리메쉬 표면에 형성된 반응 생성 물(CuI)의 자발적인 탈리 현상으로 구리의 활용률이 증가할 수 있음을 확인하였다. 반응 생성물의 CuI 상 형성은 X-선 회절 실험을 통해 확인하였으며, 표면 분석은 주사전자현미경을 이용하여 수행하여 그 결과를 보고하였다.

파이로프로세싱 전해환원 공정에서 현재 사용 중인 Pt 양극을 대체하기 위한 소재 개발은 매우 중요하다. 이 연구에서는 전 기화학 반응시 산소를 발생시키는 전도성 세라믹 양극으로서 TiN의 전기화학적 거동을 알아보았다. UO2의 전해환원이 일어 나는 동안 TiN 양극의 적합성과 안정성에 대한 평가를 진행하였다. LiCl-Li2O 용융염에서 TiN 양극을 이용하여 UO2를 전기 화학적으로 금속 U로 변환시킬 수 있었다. 반응 도중 TiN의 산화 반응은 관찰되지 않았다. 하지만 TiN 내부에서 공공이 생 기는 것을 확인하였으며, 이에 따라 소재 수명에 제한이 있을 것으로 판단된다.

본 연구에서는 산화된 피복관으로부터 염소화 공정을 통해 Zr을 선택적으로 회수하기 위한 연구의 일환으로, 단면이 개방 된 ZIRLO 피복관의 염소화 반응 속도식을 열중량분석기를 이용하여 분석하였다. 실험을 통해 산화된 ZIRLO 피복관은 400 도 염소화 조건에서 염소 기체와 반응하지 않는 것으로 확인되었다. 하지만 피복관 한쪽 혹은 양쪽 끝의 새로운 단면이 개방 될 경우 ZIRLO의 염소화 반응이 가능함을 확인하였고 반응을 완료하기까지 8 시간이 소요되었다. 이는 반응 완료까지 7 시 간이 소요된 산화되지 않은 피복관에 비하여 반응시간이 14% 증가한 것이다. Sharp-Hancock 식을 이용하여 단면이 개방된 ZIRLO 피복관과 염소 기체의 반응을 모사하기 위한 구조함수를 도출하였으며, 부피축소 모델이 본 연구 조건에서 가장 적 합한 구조 함수로 확인되었다. 또한, 본 연구를 통해 ZIRLO 피복관의 표면이 산화되어 있는 조건에서도 단면노출을 통해 염 소화 공정에 적용이 가능함을 확인하였다.

In this study, temperature variation characteristics in a flat plate with sheath heater are investigated through experiment and numerical analysis. ANSYS fluent is used to calculate the temperature distribution in the heating plate system. Transient condition is applied to observe temperature variation with the sheath heater operation, and thermal resistance on the contacted surfaces is also considered. Experimental data agree well with numerical results obtained for heat generation rate from sheath heater, Local temperature variation on the surface of flat plate is also predicted through this simulation. There is large temperature variation in the air surrounded flat plate, especially at the top of flat plate with natural convective heat transfer. These results will be helpful in optimal design for various systems equipped with sheath heater.

Numerical analysis was carried out to investigate the variation of stress and strain characteristics for the rail device in stone board cutting system. The maximum equivalent stress and strain from the vertical load acting on the device decrease as the load moves forward. Also, the maximum equivalent stress appears near the end of left, and the equivalent force of right rail device was about 1.8 times higher than that of left rail device. The variation of stress and strain distributions was remarkable at the edge of the device, and it has a strong influence on the bottom and column. These results can be applicable to optimal design of the stone board cutting device for the system safety.

CFD(Computational Fluid Dynamics) analysis was carried out to analysis the air flow characteristics of vertical axis wind turbine system with accelerating device. Geometric arc angle of the accelerating device affects the air flow characteristics in the turbine with the effect of Coanda generated from the curved surface. Air velocity distributions with the device angle variation are compared. Flow velocity increases with the device length, and the accelerating device plays a key role in decreasing the air velocity in the wake flow region. Maximum air velocity variation becomes reduced with the accelerating device, and it is largely affected by the arc angle. These results are expected to be utilized in various ways to determine the shape of accelerating device for wind power generation system.

The characteristics of temperature variation for laser diode welding system have been analyzed with numerical investigation. The laser diode is assembled with a cap and stem by projection welding. Resistance heat, in this process, is generated by electric current at the contact surface between cap and stem within a very short time. Temperature variation of laser diode is largely affected by the welding time and the heat generated from the surface. Maximum temperature of each component in the laser diode should be lower than the melting point except for cap and stem in order to prevent welding defect. Temperature distribution of each component in the laser diode is also affected by thermal conduction mechanism. Welding defect near the insulator occurs when the resistance heat is high. Appropriate resistance heat supply to the laser diode was about 400W. The results from this study could be applicable for optimal design of laser diode welding system.