• 한국기계가공학회지
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• 제9권4호
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• pp.8-13
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• 2010

The constant velocity internal grinding is a popular process for studying axle machine design and process in automobile industry. In this study, The program which gives the data of wheel size and truing diameter of ball groove is developed. As a result I obtained the data of grinding conditions makes good surface roughness get a grinding conditions. The grinding characteristics and conditions of constant velocity joint were investigated with respect to grinding feed, cutting depth, grinding time. At machine failure, the results were suddenly increased and the detailed surfaces were extremely obtained. Grinding condition was big more affected by grinding depth, grinding speed and grinding time.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.371-376
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• 1999

Stick-slip friction is present to some degree in almost all actuators and mechanisms and is often responsible for performance limitations. Simulation of stick-slip friction is difficult because of strongly nonlinear behavior in the vicinity of zero velocity. A straightforward method for representing and simulating friction effects is presented. True zero velocity sticking is represented without equation reformulation or the introduction of numerical stiffness problems. Stick-slip motion is investigated experimentally, and the fundamental characteristics of the stick-slip motion are clarified. Based on these experimental results, the characteristics of static in the period of stick and kinetic friction in the period of slip are studied concretely so as to clarify the stick-slip process.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.383-386
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• 2008

The four-bed PSA process using a layered bed of activated carbon and zeolite 5A was studied to produce a high purity hydrogen product from SMR off-gas. At a desired product purity (99.999%+), the recovery increased with decreasing the linear velocity. However, the difference of the increasing of the recovery became smaller with the decreasing of the linear velocity and then was similar from below the linear velocity 3.9 cm/s. When the adsorbents, the feed gas composition, and the operating conditions are given, the residence time is mainly a function for design of the PSA bed size. The minimum residence time exists to obtain the maximum recovery at desired product purity.

• 한국식품저장유통학회지
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• 제22권5호
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• pp.683-689
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• 2015

본 연구는 식혜의 편이성, 유통성, 저장성을 향상시키기 위하여 피막물질을 첨가하고 분무건조를 통하여 분말화를 하고자 하였다. 최적조건 설정을 위하여 반응표면분석법을 이용하였으며 독립변수는 피막물질 maltodextrin의 첨가량(%), 분무건조기의 inlet 온도($^{\circ}C$) 그리고 분무건조기내 시료의 공급속도(mL/min)로 설정하였으며 이에 따라 영향을 받는 반응변수는 분말의 흡습량(g), 용해도(%), 입자크기(${\mu}m$)로 설정하였다. 각 반응변수에 따른 회귀식은 흡습량은 p<0.001, 용해도는 p<0.05, 입자크기는 P<0.001 수준에서 유의성이 인정되었다. 그리고 각 독립변수와 종속변수의 영향을 나타내는 반응표면그래프를 이용하여 최적 분말화 조건을 예측한 결과 각 종속변수 최적점인 MD 22%, 분무건조기의 inlet 온도 $140^{\circ}C$ 그리고 분무건조기 내로 유입되는 시료의 공급속도는 51 mL/min로 예측되었다.

• 멤브레인
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• 제8권2호
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• pp.94-101
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• 1998

폴리아크릴로니트릴 공중합계의 재질인 한외여과 중공사막 (분획분자량: $5\times 10^4$ Dalton)을 이용하여 금속표면처리 세척수로부터 오일입자를 제거하였다. 오일입자를 분리하고자 할 때 막표면에서의 농도분극 현상으로 투과플럭스를 감소시키므로 농도분극을 억제하기 위하여 질소기체로 역세척을 수행하였다. 정상운전 및 역세척시간을 각기 달리하여 운전함으로써 얻어진 투과플럭스의 거동을 정량적으로 비교하였다. 실험결과, 실질투과플럭스 증가율의 산출을 기준으로 정상운전시간/역세척시간이 10분/40초인 조건이 역세척을 하지 않은 경우와 비교하여 가장 높은 증가율 (약 23%)을 보였다. 하지만, 실제 운전에서 중요하게 고려되는 시간에 따른 투과플럭스의 안정성은 정상운전시간이 연장되면 크게 떨어짐을 알 수 있었다. 막투과플럭스가 역세척압력에 무관하게 일정한 거동을 보이는 레이놀즈수 이상에서는 역세척압력이 증가할수록 투과플럭스는 n제곱승으로 증가하는 상관관계를 보였고, 원료공급속도가 증가할수록 투과플럭스의 증가정도는 상승하는 경향을 나타냈다.

• Journal of Advanced Marine Engineering and Technology
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• 제17권5호
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• pp.44-53
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• 1993

In this paper, we discuss on the control algorithm to make the wheeled inverse pendulum type mobile robot move in two dimensional plane. The robot considered in this paper has two independently driven wheels in same axel which suport and move it-self, and is assumed to have the fyro type sensor to know the inclination algle of the body and rotary encoders to know wheel's rotation angular velocity. The control algorithm is divided into three parts. The first part is for the posture and velocity control for forward-backward direction, the second is the steering control, and the last part is for the control of total system to track the given trajectory. We handle the running velocity control of the robot as part of the posture control to keep the balance because the posture relates deeply with the velocity and can be controlled by the velocities of the wheels. The control problem is analyzed as the tracking control, and the controller is realized with the state feedback and feed-forward of the reference velocity. Constructing the control system which contained one intergrator in forward path, we also realized the control system without observer for the estimation of the accumulated errors in the inclination angle of the body. To prevent the robot from being unstable state by sudden variation of the reference velocity when it starts and stops, or changes velocity, the reference velocity of which acceleration is slowly changing, is ordered to the robot. To control its steering, we give the different reference velocities for both wheels which are calculated from the desired angular velocity of the body. Finally, we presents the experimental results of the experimental robot Yamabico Kurara in which the proposed control algorithm had been implemented.

• Journal of Biosystems Engineering
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• 제16권2호
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• pp.133-141
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• 1991

This study was undertaken to investigate the structural and configurational characteristics of the tailings return-unit in the commercially available head-feed combines and to study the aero-dynamical behavior of the tailings in the units. The mathematical model of the motion of tailings in the thrower casing was developed and the simulated trajectories for different type of units was analyzed to compare with the measured ones. The air-stream velocity profile in various locations along the tailings returning duct was measured to find the effect of configurational characteristics and blade tip speed. The results of the study are summerized as follows. 1. The ejecting angle, which is the angle between the direction of the particle velocity ejecting from the blade and the horizontal axis, was found to be about $66^{\circ}$ in both the simulation and experiment. The angle was much greater than the setting angle of actual duct of the combines studied, which were $48{\sim}56^{\circ}$. By comparison of these results, it was suggested to change duct setting angle so as to reduce the frictional force, between the duct wall and tailings, by reducing the difference between the ejecting and setting angles. 2. The velocity of the air stream in the duct was in general higher in the upper bound of the duct compared to the lower and decreased as the stream went toward the end of duct. The comparison of the tailings units among the combines studied showed a superior performance with the tapered duct having small diameter in the outlet and with greater number of thrower blade.

• 대한기계학회논문집A
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• 제26권8호
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• pp.1461-1471
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• 2002

Linear motor has a lot of advantages in comparison with conventional feed mechanisms: high velocity, high acceleration, good positioning accuracy and a long lifetime. An important disadvantage of linear motor is its high power loss and heating up of motor and neighboring machine components in operation. For the application of the linear motors to precision machine tools an effective cooling method and thermal optimizing measures are required. In this paper Finite-Element-Method for the thermal behavior of synchronous linear motor is introduced, which is useful for the design and manufacturing of linear motors. By modeling the linear motor the orthotropic physical properties of the sheet metal and windings were considered and convective coefficient in the water cooler and to the surroundings was defined by analytical and experimental method. The calculated isothermal lines could analyze the heat flow in the linear motor.

• 한국정밀공학회지
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• 제32권4호
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• pp.329-337
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• 2015

In this paper, a simulation based estimation method of energy consumption of the spindle and feed drives for the NC machine tool during the cutting process is proposed. To predict energy consumption of the feed drive system, position, velocity, acceleration and jerk of the table are analyzed based on NC data and then the power and energy are calculated considering friction force and mass of the stages. Energy consumption of the spindle is estimated based on models from acceleration motion of rotating parts, friction torque and power loss of motors. Moreover, simulation models of cutting power and energy for the material removal along the NC tool paths are proposed.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.83-88
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• 2002

This study is to provide the experimental information and basic data on heat transfer characteristics of horizontal liquid film driven by hot wind. Heat transfer characteristics of the liquid film in the rectangular duct was observed and the change of film temperature was measured. The experiments were carried out for a variety of parameter, such as feed water rate and velocity and temperature of feed air. From the observation and the measurement the general understanding of heat transfer characteristics for liquid film driven by hot wind was provided.