Experiments were conducted on the operating characteristics and performance of various types of working fluid, filling amount and heat flow rate of a loop thermosyphon for cooling ESS battery container. As results of performance test on various working fluids, HFE-7100 and R-134a as a working fluids showed unstable operating and low performance due to vapor pressure drop, and performance was improved by increasing the number of vapor lines for reducing a pressure drop. In this study, n-pentane was more stable and showed better thermal performance among various working fluids.

본 연구에서는 국내 밭작물 재배농가에서 주로 사용되는 캠방식 채소 정식기를 대상으로 작동특성 및 식부장치 작동 메커니즘 분석을 수행하였다. 정식기의 주요 구성요소 및 동력전달경로를 파악하였으며, 주행속도 및 주간거리 단수 변화에 따른 최대 및 최소 작동주기를 도출하였다. 이를 바탕으로 3D모델링 및 시뮬레이션을 수행하여 식부호퍼 극하단점의 궤적 및 조건별 주간거리를 도출하였으며 필드시험을 통해 실제 주간거리와 비교 검증하였다. 주요 결과로써, 식부장치는 13개의 링크와 17개의 회전 조인트 및 1개의 하프 조인트로 구성된 1 자유도의 기구이며, 각 부분들은 캠과 링크장치들의 복합구조를 갖는다. 식부장치 요소들의 연속적이고 반복적인 운동에 의해 식부호퍼는 지면과 연직인 자세를 유지하며 묘를 안정적으로 정식한다. 동력은 엔진과 변속기를 통해 주행부 및 식부장치로 전달되었으며 식부 장치의 최대 및 최소 주간거리는 각각 약 900 mm 및 350 mm이다.

본 연구에서는 국내에서 주로 사용되는 채소 정식기를 대상으로 전체적인 작동 특성을 분석하였다. 식부장치 거동에 영향을 주는 주요 구성요소 및 동력전달경로를 파악하였으며, 식부장치의 링크 구조를 기구적으로 분석하고 3D모델링 및 시뮬레이션을 수행하였다. 이를 바탕으로 식부호퍼 극하단점의 궤적을 분석하였다. 또한 엔진회전속도 및 식부변속단수 변화에 따른 주간거리를 도출하고 필드시험을 통해 검증하였다. 주요 결과로써, 식부장치는 10개의 링크와 13개의 회전 조인트로 구성된 1 자유도의 기구이며 각 부분들은 4절 링크식으로 구성되어 있었다. 링크장치의 거동에 의해 식부호퍼는 일정한 자세를 유지하면서 연직 방향으로 묘를 심어준다. 동력은 엔진을 통해 주행부 및 식부로 전달되었으며 식부장치의 최대 및 최소 주간거리는 각각 428.97mm, 261.20mm로 나타났다.

본 연구에서는 국내에서 주로 사용되는 롤러식 양파 파종기의 작동 특성을 분석하였다. 롤러식 양파 파종기의 주요 구성요소 및 전체 작동 메커니즘을 분석하였다. 또한, 동력전달경로를 분석하여 주요 성능인자인 포트의 이동속도와 롤러의 회전속도를 파악하였으며 계측을 통하여 검증하였다. 롤러식 양 파 파종기의 주요부에 대한 3D모델링 및 시뮬레이션을 수행하였으며 이를 바탕으로 롤러에 의한 상토 의 압축정도를 파악하였다. 본 연구를 통해 파악한 포트트레이의 이동속도는 7.49×10-2m/s이며 4개 의 롤러의 회전속도는 모두 22.13rpm인 것으로 나타났다. 롤러 돌기에 의한 상토 압축 정도는 약 9.8×10-3m인 것으로 나타났다. 롤러식 양파 파종기의 주요 성능 파라미터는 롤러 돌기 형상, 포트트레 이 및 롤러 속도, 배종드럼의 표면마찰계수 및 구멍크기/형상인 것으로 판단되며 향후 연구로써 시뮬레 이션 및 시험을 통한 파라미터의 최적화가 필요하다.

Magnetostrictive actuator is fabricated with powder nano bonding method instead of sputtering method. Fabrication process and experimental measurement method for magneto-mechanical characteristics is proposed. For the design of highly flexible magnetostrictive actuator, TbDyFe nano powder bonding with Teflon substrate is adopted. The fabrication process for Teflon substrate and nano powder bonding is suggested and magnetostrictive behaviors are investigated. Variable magnetic field is applied to measure the magnetostrictive characteristics and magnetostriction is measured with different waves and different magnitude of magnetic field.

Pneumatic cylinder actuators are significantly utilized for industry automatic systems in the fields of mechanical applications. We propose a novel control method for pneumatic cylinder actuator systems including stochastic friction dynamics. The proposed control mechanism is linearly composed of nominal control and auxiliary control variables. The former is designed from linear system model without friction terms by using a previous linear system theory and the latter is constructed as a function of friction estimation which is carried out by a well-known least square algorithm for reducing the control error due to random friction dynamics. We accomplish numerical simulation to demonstrate reliability of the proposed control method and conduct a comparative study to improve its superiority.

This paper presents the impact of partial shading on CuInxGa(1-x)Se2(CIGS) photovoltaic(PV) modules with bypass diodes. When the CIGS PV modules were partially shaded, the modules were under conditions of partial reverse bias. We investigated the characterization of the bypass diode and solar cell properties of the CIGS PV modules when these was partially shaded, comparing the results with those for a crystalline silicon module. In crystalline silicon modules, the bypass diode was operated at a partial shade modules of 1.67 % shading. This protected the crystalline silicon module from hot spot damage. In CIGS thin film modules, on the other hand, the bypass diode was not operated before 20 % shading. This caused damage because of hotspots, which occurred as wormlike defects in the CIGS thin film module. Moreover, the bypass diode adapted to the CIGS thin film module was operated fully at 60% shading, while the CIGS thin film module was not operated under these conditions. It is known that the bypass diode adapted to the CIGS thin film module operated more slowly than that of the crystalline silicon module; this bypass diode also failed to protect the module from damage. This was because of the reverse saturation current of the CIGS thin film, 1.99 × 10−5 A/cm2, which was higher than that of crystalline silicon, 8.11 × 10−7 A/cm2.

The experimental study for an operational characteristics and performance of the sodium heat pipe were carried out. For an experiment, the heat pipe which is 1000mm length and 25.4mm diameter of stainless steel container with 50 mesh of screen wick using sodium as a working fluid is manufactured and tested as functions of heat flow rate, inclined angle and operating temperature. The test results are as follows. During the start-up, frontal start up was observed because of the vapor density increasing as increased the hot zone. Also, the heat pipe showed uniform temperature over than 420℃ of the operating temperature. The average heat transfer coefficient increased as the heat flux and the vapor temperature increase, and the range of the total thermal resistance was 0.075～0.04℃/W at the 12～53.55kW/m2 of heat flux and 500～750℃ of operating temperature. The maximum heat flow rate was 750W at the 10 degree of top heating mode.

The loop thermosyphon has been designed and tested for cooling several hundreds watt of heat. This cooling system is consisted of copper block, condenser which is fabricated with tubes and fins and transport lines. In this research, operational characteristics and limitation of the loop thermosyphon were investigated as a function of fill charge ratio, thermal load, vapor temperature and effective head. The experimental results shows that the heat transfer limitation is dominated by vapor temperature and effective head. Also, the correlation for the heat transfer limitation is presented and showed good agreement. The evaporating heat transfer coefficient is affected by vapor temperature and heat flux, but the fill charge ratio and liquid head are minor factor.

A heat pipe heat sink which is possible to frozen start up at the lower than -20℃ by using a VCHP was designed, manufactured and tested. The VCHP uses water and nitrogen gas as the working fluid and non-condensable gas. The test results showed that the VCHP heat sink started up successfully at the range of -20 to -30℃ of the ambient temperature and 1000 to 2600W of the heat flow rate. The thermal resistance of the VCHP heat sink decreased as increased the heat flow rate and the ambient temperature since the active zone of VCHP increased.

The operational characteristics of a VCHP in the various operation conditions were investigated. A water heat pipe including nitrogen gas as a non-condensable gas was designed and manufactured using a copper tube with 12.7㎜ diameter and 480㎜ length. Experimental data showed that the length of non-active zone mostly depend on the temperature of the vapor and the non-condensable gas. And the heat flow rate was negligible parameter at the same vapor temperature in the range of the experiment. As the vapor temperature increase and the non-condensable gas temperature decrease, the non active zone was increased. The calculated data by using the flat front model and the experimental results showed same tendency.

The trends in building construction these days are moving towards having better work spaces and greater suitability for the use of information technology. Therefore people can work in a more relaxed delightful and pleasant environment. Accident such as like fire could cause the mass destruction of human beings. This paper aims to evaluate the path of the spread of a fire and the suitability of fire fighting appliances for maximum egress time. General advanced phase of compartment. Aswell, we analyzed and verified the path of the flame in compartment fires. Also we conducted an analysis of the adaptation of sprinkler systems concerned with sprinkler RTI. Moreover those evaluation is made more earlier by the development and use of computer simulation program and rapid progress to apply PBFD (Performance Based Fire Design).

In this paper, computer simulation was used for researching into the estimate of flash over result from compartment fire and the characteristics operation of sprinkler RTI. Computing simulation, we analyzed and verified the path of the flame in compartment fire and the adaptation of sprinkler system concerned with sprinkler RTI.