• Journal of Environmental Health Sciences
• /
• v.21 no.2
• /
• pp.20-26
• /
• 1995

The objective of this study is to estimate the effect of the bed expansion and the characteristics of attached biomass in the start-up in the anaerobic fluidized bed reactor(AFBR). The fluidized bed reactor was operated with bacteria supported on the bed of granular activated carbon(GAC). The reactor was operated at 35$\circ$C, 5 kg $COD/m^3\cdot day$ at bed expansion varying from 0 to 100% with soluble glucose wastewater(5,000 mg/l). When the effluent reached a steady state at 100% of bed expansion, maximum COD removal efficiency of 87.3% and 0.031 $m^3CH_4/kg COD_{removed}$ were obtained. At higher bed expansion, COD removal efficiency, methane production rate and biogas production rate increased. Especially, at 50% of bed expansion, the efficiency of the treatment increasedg rapidly in the AFBR. The biomass colonized in the pits and crevices of the GAC particle and no complete biofilm was established in the bioreactor during the experiment.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.522-524
• /
• 1994

This paper presents power factor and distortion improvement methods via active boost converter and mode select. This method not only reduces the current and voltage distortion but also the physical size and expected low cost. Optimum parameter values arc derived to minimize the harmonise in the input current. A theoretical analysis, simulation and experimental results arc presented.

• Journal of Astronomy and Space Sciences
• /
• v.23 no.2
• /
• pp.161-166
• /
• 2006

In this paper, we describe the RLG current stabilizer circuit for attitude control in the satellite. The RLG makes use of the Sagnac effect within a resonant of a HeNe laser. The difference between two discharge currents causes one of the gyro bias errors. The theoretical background and current stabilizer are introduced. It is verified that the circuit designed is applicable to the test of input voltage and temperature.

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.874-877
• /
• 2004

This paper presents the bus controller analysis of a power control unit of GEO satellite with 3kW power output. The sensing error of bus voltage produce control signal of the shunt switch assembly and the battery power converter, and the tolerance of error signal generated decide the stability of proposed system. The worst case analysis considered for the initial tolerance, temperature effect, tolerance of end of life is peformed to verify a designed bus controller. And also, the stability of system proposed according to moving of zero and pole values by some component failures is analyzed.

• Journal of Institute of Control, Robotics and Systems
• /
• v.16 no.8
• /
• pp.727-734
• /
• 2010

This paper deals with an anti-sway control for a ship-mounted container crane which is disturbed by the wave-induced motions of the ship. We derive a simple dynamics of the ship-mounted container crane with an active anti-sway control system and transform it into a dynamic function for a horizontal variable on the absolute coordinate. Then we propose an control method to reduce pendulation of the spreader and compare its performance with well-known feedback linearization control in computer simulation.

• Journal of Environmental Health Sciences
• /
• v.22 no.3
• /
• pp.72-80
• /
• 1996

This study was carried to investigate the biodegradability of phenol wastewater in the sluge blanket-packed bed reactor(SBPBR). The reactor consisted of two regions. The lower region was a sludge blanket of 0.5 m height and the upper region was a packed-bed. The phenol and COD concentration of the effluent, the gas production and the composition of gas were measured to determine the performance of the anaerobic wastewater treatment system as the phenol concentration of the influent was increased from 600 to 1800 mg/l. Stable biodegradation of phenol wastewater could be achieved with the anaerobic treatment system from 600 to 1200 mg/l of the influent phenol concentration. But the SBPBR system was getting more serious at 1800 mg/l of influent phenol concentration. At the steady state of the influent phenol concentration of 600-1200 mg/l, the treatment performance showed the phenol removal efficiency of 94.5~96.3%, the COD removal efficiency of 93.3~96% and the gas production of 4.94~9.64 l/day.

• Proceedings of the KIPE Conference
• /
• 2002.07a
• /
• pp.773-776
• /
• 2002

The battery charger of spacecraft has two different modes of operation respectively. One is the bus voltage regulation mode and the other is the charge current regulation mode. And also the battery discharger provide the power during eclipse mode of spacecraft. In this study, a test model of the battery charger and discharger using hi-directional converter are designed and analyzed. These Battery Charger and Discharger is introduced the modular converter method that can be added the converter modules according to the load variation.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2002.07a
• /
• pp.121-127
• /
• 2002

당근은 미나리과에 속하는 직근성 채소로서 비타민A가 다량 함유된 건강식품으로 우리나라에 6,000㏊ 내외로 재배되고 있다. 재배지역은 우리나라 전체 재배면적 중에서 남제주군 지역이 44.5%, 경남 김해, 양산지역이 16.1%, 강원 평창지역이 11.1%를 점유하고 있으며 총 재배면적의 70% 이상이 주산단지 화되어 있어 기계화가 용이한 작목이다. 당근재배에 있어서 10a당 작업단계별 노동투하시간을 보면 전체 100.2시간으로 경운정지, 방제작업만 기계화가 이루어지고 대부분 인력에 의존하고 있는 실정이다. (중략)

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2002.07a
• /
• pp.128-134
• /
• 2002

당근 수확작업에 대한 기계화 요구도가 높은 반면에 아직까지 수확작업의 기계화는 그다지 진전되지 못하고 있는 실정이다. 지금까지의 당근 등 근채류의 수확작업은 경운기용 또는 트랙터용 굴취기를 이용하여 작물을 지상위로 노출시키고 인력으로 수집하는 방법이 대부분이며 흙이나 돌 등 협잡물의 선별은 곤란하다. 또한 줄기절단 등 수확 후처리 작업이 기계화되지 못해 노동부담이 크다. (중략)

• Journal of the Korean Magnetics Society
• /
• v.6 no.6
• /
• pp.375-381
• /
• 1996

This study is conducted to develop the high frequency inductor with ferro-yoke for the surface shape control. A 3- Dimensional simulation program based on the finite element method is developed for calculating electromagnetic field of the high frequency inductor. The validity of the program and the capability to control the liquid metal shape are confirmed by comparison between the results from calculation and those from measurement.