• 한국환경농학회지
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• 제15권3호
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• pp.355-361
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• 1996

The Purpose of this study was to investigate the effect of the Change in the operating conditions on rotary turning compost plants. The major parameters investigated were moisture content and mixing of the sawdust and pig farm wastewater. Pig farm scale composting plants with mixing rotary were used in this study. Wastes used for the study were sawdust, pig manure, urine and wastewater. When the moisture content was 75%, the compost product obtained from the plants had better physical characteristics than that obtained from the plants with moisture contents of 70%, 80% and 85%.(two a day mixing). When the turning was twice a day, the compost product obtained from the plants had better characteristics than that obtained from non-mixing.(moisture content 75%). C/N ratio, pH value and coliform bacterial population were stable in the compost.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.230-235
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• 2000

In this paper, a surface generation model is presented to simulate surface roughness profile in turning operation. The simulation model takes into account the effect of tool geometry, process parameters, rotational errors of spindle, and the relative vibration between the cutting tool and workpiece. The surface roughness profiles are simulated based on the surface-shaping system. The model has been verified by comparing the experimental values with the simulation values. It is shown that the surface simulation model can properly predict the surface roughness profile.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.300-306
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• 2005

This paper presents the methodology for measuring eccentricity of the machined cylindrical part using CCS(cylindrical capacitance spindle sensor) signal in the CNC turning process. We use capacitance type sensor to take full advantage of averaging effect by using large capacitance area to encompass the whole side of a sensor. The intentionally proposed initial eccentricity is applied to the experimental testpieces, and their resultant relationships between CCS orbits and eccentricities are investigated. As a result, the possibility as a automatic detection apparatus for the CNC lathe is considered based on the linearities of CCS signal and magnitude of eccentricity of machined cylindrical surfaces.

• 한국생산제조학회지
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• 제21권1호
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• pp.144-149
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• 2012

The cutting characteristics of hardened aluminum alloy A17075-T6 were investigated during turning processing. Under variation conditions of cutting speed, depth of cut, and feed rate, the characteristics of cutting force, surface roughness, and machined texture were investigated. Surface roughness became worse in proportion to the increase of the feed rate. The thickness of material alteration layer which is derived from the effect of cutting force was the biggest when feed rate 0.148mm/rev. This research confirmed that the deformed layer is dominantly dependent on the variation of feed rate.

• 한국자원식물학회지
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• 제9권1호
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• pp.63-69
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• 1996

양파 재배(栽培)에 있어서 기계(機械)를 이용(利用)하여 수확(收穫)의 성력화(省力化)로 노동력(勞動力)과 생산비(生産費)를 절감(節減)하기 위해 본(本) 시험(試驗)을 수행(遂行)한 결과(結果)는 다음과 같다. 1. 기계(機械)를 이용한 양파 굴취수확(掘取收穫)은 관행인력굴취수확(慣行人力掘取收穫)에 비해 트랙터 후부(後部)에 굴취기(掘取機)를 부착(附着)해 서 수확(收穫)한 굴취수확(掘取收穫)이 90-93%로 성력효과(省力效果)는 가장 좋았다. 2. 트랙터 후부(後部)에 굴취기(掘取機)를 부착(附着)한 수확기(收穫機)의 성력효과(省力效果)는 관행인력수확(慣行人力收穫)에 비해 37%의 작업시간(作業時刊)을 절감(節減)하여 37%의 작업비(作業費)를 절멸(節滅)했다.

• 한국자원식물학회지
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• 제8권3호
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• pp.297-302
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• 1995

감자 재배(栽培)에 있어서 기계(機械)를 이용(利用)하여 수확(收穫)의 생력화(省力化)로 생산비(生産費)를 절감(節減)하기 위해 본(本) 시험(試驗)을 수행(遂行)한 결과(結果)는 다음과 같다. 1. 기계(機械)를 이용(利用)한 감자 굴취수확(掘取收穫)은 관행인력수확(慣行人力收穫)에 비해 트랙터 후부(後部)에 굴취기를 이용(利用)한 것이 94%로 생력효과(省力效果)에서 관행인력수확(慣行人力收穫)에 비해 42-45%의 노력시간(努力時間)을 절약(節約)함으로 42-45%의 작업비(作業費)를 절감(節減)했다.

• 수산해양기술연구
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• 제54권3호
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• pp.239-245
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• 2018

International Maritime Organization (IMO) has established standards for ship manoeuvrability and applied these standards for vessels over 100 meters in length that built since 2004 (IMO, resolution MSC.137[76]). These standards are no exception to fishing vessels. In this study we carried out a manoeuvring simulation of the new model ship (Stern trawler) of fisheries training ship of Pukyong National University based on Kijima's empirical formula. The formula takes into account of the effect of stern shape or does not take into account of the effect of stern shape. Also we checked whether the simulation results of turning motion of model ship meet IMO manoeuvrability criteria and then compared trajectories between the simulation results of model ship and the results of real sea trial test of the existing ship. In conclusion, Kijima's empirical formulas can estimate the manoeuvrability of fishing vessels at design stage approximately, it needs more parameters of fishing vessel own in case of expressing the manoeuvrability of fishing vessel accurately.

• 한국주조공학회지
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• 제21권6호
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• pp.350-358
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• 2001

The machinability of cast iron is closely related to its microstructural property. In this study, the effect of graphite mophology and matrix microstructure on machinability in several commercial cast irons(GC 25, GCD 45, GCD 50, GCD 70, GCD HSMo, GCMP) was investigated. To estimate the machinability, turning test was carried out under conditions of spindle speed 80m/min, depth of cut 0.25mm, feed 0.16mm/rev and cutting distance 1 km. Thrust force in turning test decreases in the order of GCMP, GCD 70, GCD 50, GC 25, GCD 45 and GCD HSMo. i.e. machinability increases in this order. The superior machinability of GC 25 is caused by flake type graphite which acts as chip braker and provides lubrication during machining. Consequently, soft ferritic cast irons exhibit superior machinability compared with pearlitic cast irons.

• 한국항해항만학회지
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• 제26권1호
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• pp.1-7
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• 2002

전복한 저건현 내항 탱커의 사고 원인을 조사하기 위하여 복원성에 영향을 미치는 자유표면영향과 저건현 선박에서 발생하는 해수침입, 침수침하 현상에 대하여 알아보았다. 피리고 선회시에 발생하는 경사 모멘트륵 계산하고 사고 선박의 경사 모멘트를 추정하였다. 이상의결과로부터 사고 선박의 복원성 상실에 의한 전복 원인을 고찰하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권8호
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• pp.459-466
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• 2000

In this paper, we propose an attitude controller for an unstructured object using CMG(Control Moment of Gyro) subsystem, which has a stabilizer function. The CMG subsystem consists of one motor for spinning the wheel and the other motor for turning the outer gimbal. While the wheel of CMG subsystem is spinning at high speed, applying force to the spin axis of the wheel leads the torque about the vertical axis. We utilize the torque to control the attitude of object in this study. For the stabilizer function, in additiion, holding the load at the current position, the power applied to the gimbal motor of CMG will be cut, which result in the braking force to stop the load by gyro effect. However, due to the gear reduction connected to outer gimbal, slow load motion cannot generate the braking force. Thus, in this study, we are willing to make a holding force by applying control power to the gimbal motor from the signal of piezoelectric gyroscopic sensor that detected the angular velocity of the load. These two features are demonstrated in experiment, carrying a beam with crane. As a result, load was started to rotate by controlling gimbal positiion and was stopped by turning off the gimbal power. Moreover, slow movement of the load was also rejected by additional control with gyroscopic sensor.