• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1373-1378
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• 2007

Metal forming ins the process changing shapes and mechanical properties of the workpiece without initial material reduction through plastic deformation. Above all, because of hot working carried out above recrystallization temperature can be generated large deformation with one blow, it can produce with forging complicated parts or heat resisting super alloy such as Inconel 718 has the worst forgeability. In this paper, we established optimal variation of hot heading precess of the Inconel 718 used in heat resisting component and evaluated mechanical properties hot worked produce. Die material is SKD61 and initial temperature is $300^{\circ}C$. Initial billet temperature and punch velocity changed, relatively. Friction coefficient is 0.3 as lubricated condition of hot working. CAE is carried out suing DEFORM software before making the tryout part, and it is manufactured 150 ton screw press with optimal condition. It is known that forming load was decreased according to decreasing punch velocity.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.585-590
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• 2001

Turbine blade is subject to torsional load by torsion-mount, centrifugal load by rotation of rotor and repeated bending load by steam pressure. Turbine with partially cracked blade has normal working condition at initial repair time but vibratory working condition at middle repair time due to crack growth. Finite element analysis on turbine blade indicates that repeated bending load out of all loads is the most important factor on fatigue strength of turbine blade. Therefore, this study shows root mean square roughness has linear relation with stress intensity factor range in 12% Cr steel and can predict loading condition of fractured turbine blade.

• 한국자동차공학회논문집
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• 제9권6호
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• pp.170-177
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• 2001

Turbine blade is subject to torsional load by torsion-mount, centrifugal load by rotation of rotor and repeated bending load by steam pressure. Turbine with partially cracked blade has normal working condition at initial repair time but vibratory working condition at middle repair time due to crack growth. Finite element analysis on turbine blade indicates that repeated bending load out of all loads is the most important factor on fatigue strength of turbine blade. Therefore, this study shows root mean square roughness has linear relation with stress intensity factor range in 12% Cr steel and can predict loading condition of fractured turbine blade.

• 환경위생공학
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• 제23권1호
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• pp.49-56
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• 2008

Foodwaste will be able to treat is 13,000 ton/day. $18{\times}10^{13}$ won/yr are wasted with the foodwaste treatment. As a result, the initial working condition. These are given as follows : On the 1st. week, the foodwaste of the 130 ton/week(digest sludge : input foodwaste = 20 : 1) is being put into a DRANCO system by the space of 2 day. On the 2nd week, the food waste of the 130 ton/week(5 day) is being put into a DRANCO system by the space of 2 day. On the 3rd week, the foodwaste of the 130 ton/week is being put into a DRANCO system by the space of 3day. On the 4th week, the foodwaste of the 350 ton/week is being put into a DRANCO system. After that time, increase the quantity than last week is 10%. Under steady-state working condition, the methane content of the biogas is more then 55%. The $NH_3-N$ content of the digest sludge is under 3,500ppm. The VFA content of the digest sludge is under 1,500ppm. The pH is more then 8. The TS content of the digest sludge is $18{\sim}22%$. The VS content of the digest sludge is under 65%.

• 한국보육지원학회지
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• 제8권3호
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• pp.249-272
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• 2012

본 연구는 보육발전과정에서 보육교사 처우관련 정책이 소외되어 왔다는 문제를 인식하고 보육교사의 처우현황을 분석하여 이의 개선방안을 제안하고자 시도되었다. 이를 위해서 보육교사 처우와 관련된 정부의 정책, 정부출연 연구기관의 연구물, 관련 통계, 그리고 선행연구 문헌을 수집 분석하였다. 본 연구의 분석결과 보육교사의 처우가 유사직종의 보수 수준에 비해 현저하게 낮아 시급한 개선이 요구되고 있음을 확인하였다. 이러한 문제점을 개선하기 위해서 보육교사의 학력과 자격급수가 고려된 보수체계의 마련, 호봉 승급제도의 실시, 수당항목의 명시적 제시 등을 제안하였다. 이외에도 원장초임 호봉의 상향조정, 초과근 무수당의 지급규정 준수, 정부 미지원 어린이집 교사의 인건비 관련 규정 명시, 그리고 정부지원어린이집에 대한 정부의 인건비 지원 비율 조정 등과 같은 보육교사 처우를 위한 개선책이 시급하게 마련되어야 할 것을 제안하였다.

• 대한기계학회논문집B
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• 제33권9호
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• pp.718-721
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• 2009

A new progressive advanced approach (Loop thermosyphon Thermoelectric Power generation System) is suggested to optimize heat recovery ability from vehicle exhaust gas. As an initial look at device feasibility, the present new TE system adopted the loop thermosyphon as a cooling heat exchanger. The TE system with loop thermosyphon was investigated in terms of working fluids, instability of system, amount of working fluid, and so on. Basically, the present experimental works have been focused on finding the optimum working condition of the system to improve thermoelectric power output and to obtain stable power generation to operate hybrid vehicles. The present experimental results with the loop thermosyphon TE module shows possibilities as an improved TE system for future thermoelectric hybrid vehicles.

• 대한기계학회논문집B
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• 제29권2호
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• pp.169-179
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• 2005

Nucleate boiling experiments on heating surface of constant wall temperature were performed using R113 for almost saturated pool boiling conditions. A microscale heater array and Wheatstone bridge circuits were used to maintain a constant wall temperature condition of heating surface and to measure the heat flow rate with high temporal and spatial resolutions. Bubble images during the bubble growth were taken as 5000 frames per second using a high-speed CCD camera synchronized with the heat flow rate measurements. The bubble growth behavior was analyzed using the new dimensionless parameters for each growth regions to permit comparisons with previous experimental results at the same scale. We found that the new dimensionless parameters can describe the whole growth region as initial and later (thermal) respectively. The comparisons showed good agreement in the initial and thermal growth regions. In the initial growth region including surface tension controlled, transition and inertia controlled regions as divided by Robinson and Judd, the bubble growth rate showed that the bubble radius was proportional to $t^{2/3}$ regardless of working fluids and heating conditions. And in the thermal growth region as also called asymptotic region, the bubble showed a growth rate that was proportional to $t^{1/5}$, also. Those growth rates were slower than the growth rates proposed in previous analytical analyses. The required heat flow rate for the volume change of the observed bubble was estimated to be larger than the heat flow rate measured at the wall. Heat, which is different from the instantaneous heat supplied through the heating wall, can be estimated as being transferred through the interface between bubble and liquid even with saturated pool condition. This phenomenon under a saturated pool condition needs to be analyzed and the data from this study can supply the good experimental data with the precise boundary condition (constant wall temperature).

• Journal of Pharmaceutical Investigation
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• 제22권4호
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• pp.289-300
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• 1992

The counter-transport phenomena in the hepatic transport of 1-anilino-8-naphthalene sulfonate (ANS) were kinetically investigated by analyzing the plasma disappearance-time profiles and the transport into the isolated hepatocytes. In vivo "counter transport phenomena" were simulated based on the perfusion model which incorporated the carrier-mediated transport and the saturable intracellular binding. The condition that the mobility of carrier-ligand complex is greater than that of free carrier is not essential for the occurrence of counter-transport phenomenon. To examine the inhibitory effects on the initial uptake of a ligand by the liver, it is necessary to judge whether the true counter-transport mechanism (trans-stimulation) is working or not. The initial plasma disappearance curves of ANS were then kinetically analyzed based on a two-compartment model, in which the ligand is eliminated only from the peripheral compartment (liver compartment). No effects on the initial plasma disappearance rates of ANS were observed after preloading of bromophenol blue (BPB) or rose bengal (RB) in the liver. Inhibitory effect of BPB or RB on the initial uptake (or efflux) rates of ANS by the isolated hepatocytes were not observed, suggesting that the true counter transport mechanism is not working. In conclusion, checking the preloading effects of transstimulation on the initial uptake of a ligand by the liver could be a useful criterion for carrier cycling and common use of the same carrier between two ligands. However, one cannot exclude those possibilities even if the preloading effects cannot be observed.

• Composites Research
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• 제26권4호
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• pp.265-272
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• 2013

섬유강화플라스틱(Fiber-reinforced plastic, FRP)은 복합재료 보트를 만드는 데 주 구조물로 사용되고 그것들 대부분은 몰드에서 만들어진다. 이러한 제품들은 몰드에서 분리될 때나 높은 온도의 환경에서 변형이 생긴다. 그러므로 다양한 제작 및 작동 조건에서 적층복합재료 구조물의 변형에 대한 실험적 조사 및 평가는 필수적이다. 불포화 폴리에스테르수지와 유리섬유를 이용하여 L-shape과 Curve-shape 시편을 제작하였다. 경화제 비율과 제작온도, 네 가지 작동온도가 입력인자(독립변수)로 사용되었고 출력인자는 시편에서 측정되는 변형이다. 결과로부터 경화제 비율이 높을수록 또한 제작온도가 높을수록 변형이 작게 생김을 알 수 있었다. 작동온도가 상승할 때 초기 변형 값에 따라 큰 변화를 보였다. 또한 변형 값이나 입력인자들은 회귀 방정식으로부터 예측할 수 있었다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2000년도 특별강연 및 추계학술발표대회 개요집
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• pp.31-33
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• 2000

Welding processing is used in the various industrial fields such as shipbuilding, car, airplane and steel structure, etc.. But the welding process has a bad working condition and lack of skillful worker. The welding depended on man power causes low productivity and difficulty in keeping continuous and stable quality control. This paper shows the development results of welding mobile robot with the several functions such as continuous/intermittent welding, initial welding speed control, acceleration control, crater and deceleration speed control in welding end. The robot is developed based on microprocess which is intel 80c196kc.