• 한국식품영양과학회지
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• 제28권4호
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• pp.890-894
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• 1999

Microencapsulation of anchovy oil as a core material in sodium alginate as a wall material was inves tigated. Microencapsulation was accomplished by injecting an oil/water emulsion, consisting of a mixture of liquefied sodium alginate and emulsifier, under high pressure through an orifice submerged in a calcium lactate solution. Microcapsules suspended in a dispersion fluid were observed under a fluorescence mi croscope to verify the presence of the capsules and to note coalescence or degradation of the capsules. Optimum conditions for microencapsulation of anchovy oil were obtained when 1.0% aqueous solution of sodium alginate contained 3% of a 1:1 ratio of ESPR 25(polyglycerine＋polylinoleate) and TW 20(sorbitan laurate＋ethylene oxide) as an emulsifier in terms of capsule size and size distribution, and emulsion stability. The airless sprayer produced microcapsules with a diameter between 15.9 and 73.9 m with different concentration of a wall material. The optimum mixing ratio of wall material to core material was 90:10(wt/wt). 0.2% calcium lactate was appropriate as a dispersion fluid.

• 한국주조공학회지
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• 제14권1호
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• pp.62-74
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• 1994

The concentration and particle size distribution of non-metallic inclusions which suspended in the molten aluminum at $700^{\circ}C$ were measured by using LiMCA apparatus. The result revealed that the number of inclusions increased with increasing the applied current or decreasing the orifice diameter, while decreased with increasing the purity of aluminum. And also, it was found that the number of inclusions increased with increasing the amount of boron added to molten aluminum. This was found to be attributed to the formation of the inclusions of TiB and $V_3B_2$. It was investigated that the average concentration of inclusions in a constant volume of 20ml of molten aluminum was increased in the order of pure molten aluminum, molten aluminum containing 20ppm of boron and molten aluminum used repeatly in the experimental casting in this study.

• 한국분무공학회지
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• 제4권4호
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• pp.30-37
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• 1999

The breakup characteristics of liquid sheet formed by the liquid rocket injector has a close relation with the combustion efficiency. In this paper, basic characteristics of droplet size and velocity distribution were measured with PDPA for the Like Doublet Impinging Injector. Test variables were the angle of impact, the diameter of orifice and jet velocity. Water was used as test fluid. As a result, for impingement angle less than 90 degree, following correlations were obtained between drop size and design parameters : $D_{32}({\mu}m)=295.0{\times}V^{-0.09}\times(2\theta)^{-0.1}{\times}d^{0.072}$. For impingement angle greater than 100 degree, drop sizes were increased but eventually converged to a certain limiting value.

• 유공압시스템학회논문집
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• 제6권1호
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• pp.25-31
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• 2009

This study presents an analytical model of hydraulic clutch system of a power shift transmission to analyze pressure modulation characteristics. A typical hydraulic clutch system was modeled by using AMESim in which the parameters of major components were measured for simulation. Test apparatus was established using the components of power shift and power shuttle clutches with instrumental equipment. The results of simulation and experiment were so close that the proposed analytical model in this study was validated. However the cylinder model analogized clutch dynamics need to be improved in future study. The effects of parameters of orifice diameter, accumulator stroke and oil temperature on pressure modulation were analyzed respectively. The results of parameter sensitivity analysis show that modulation time and set pressure can be easily adjusted by changing parameter values. It is also found that the hydraulic clutch system used in this study is so susceptible to oil temperature that cooling equipment is necessary.

• 한국안전학회지
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• 제14권1호
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• pp.3-9
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• 1999

The vortex tube is a simple device which splits a compressed gas stream into a cold stream and a hot stream without any chemical reactions. Recently, vortex tube is widely used to local cooler of industrial equipments and air supply system. In this study, the insulation effect of surface on the efficiency of vortex tube was performed experimentally. The experiment is carried out for nozzle area ratio of 0.194, diameter ratio of cold end orifice of 0.6 and input pressure ranging from 0.2Mpa to 0.5Mpa. The purpose of this study is focused on the effect of surface insulation of vortex tube with the variation of cold air mass flow ratio. The results indicate that the temperature difference of cold and hot air are higher about 12% and 30% than that of not insulated vortex tube respectively. Furthermore, for the insulated vortex tube, the similarity relation for the prediction of cold end temperature as the function of cold air mass flow ratio and input pressure is obtained.

• 설비공학논문집
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• 제12권8호
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• pp.782-790
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• 2000

A numerical study has been conducted to characterize the transient pressure in a building water supply system with an air chamber by utilizing a commercial code that employs the method of characteristics. Some results produced for the purpose of verification in the study agree quite well with the previously reported. Several parameters are then varied. Among them are the valve closure time, the wave speed, the static pressure, the polytropic exponent, the air chamber volume, the inner diameter and the shape of orifice in the air chamber, etc, while the water temperature and velocity are kept constant at $20^P{circ}C $,/TEX> and 0.8 m/s, respectively, Results reported in this parametric study may be useful to understand the unsteady behavior of the system.

• Journal of Chest Surgery
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• 제18권4호
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• pp.663-666
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• 1985

Whatever a surgeon choose aortic prosthesis in aortic stenosis, it will always provoke some degree of obstruction to flow due to its smaller effective orifice area to tissue annulus. Occasionally, we meet small aortic annulus to his or her body surface area in aortic valve replacement. The small annulus remains a problem in that both tissue and mechanical prosthesis have significant pressure gradients between LV and aorta in resting or exercising states. In these circumstances, diverse surgical procedures, such as tilting disc prosthesis, supraannular position of aortic prosthesis, and enlargement of aortic root [including aortoventriculoplasty, translocation of aortic valve, & double outlet of LV by valved conduit], were applied. We experienced one case of aortic stenosis with small aortic annulus. Systolic pressure gradients between LV & aorta were 90 mmHg. Diameter of annulus was 19 mm. So we performed patch enlargement of aortic root by Manouguian and AVR with St. Jude medical valve 23 mm.

• 대한기계학회논문집
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• 제16권3호
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• pp.569-577
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• 1992

본 연구에서는 주연소실쪽의 오리피스 근방에서 점화를 하는 부실붙이 연소실 에서 부실의 크기, 오리피스 크기를 변수로 하여 화염분출이 연소에 미치는 영향을 파 악하였다. 또한 이들의 결과를 부실쪽에서 점화하는 경우와 비교하여 주연소실쪽 점 화방식의 화염분출효과를 평가하였다.

• 드라이브 ㆍ 컨트롤
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• 제11권3호
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• pp.41-46
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• 2014

The neutral valve for controlling the HST is one of the important valves for the vehicle control. Neutral valve takes a role of blocking or transmitting power to the vehicle. The operating principle of the neutral valve was developed through the analysis model. We also investigated the logical validity by analyzing the results of the analysis model. The analysis model was developed by using SimulationX witch is commercial software. The number of holes in the piston was selected as a variable initial compression of the spring, and the magnitude of the pressure pulsations and the diameter of the orifice for the sensitivity analysis were performed to design sensitivity analysis of the neutral valve.

• 한국추진공학회지
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• 제4권4호
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• pp.36-41
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• 2000

액체로켓에서 설계된 추진제를 엔진내로 분사하고, 미립화 및 혼합시키는 분사기고서, 널리 사용되어온 이유체 충돌분사기의 혼합특성은 연소안정성 및 연소효율에 주요한 영향을 미치는 인자이다. 따라서 본 연구는 이유체 충돌 분사기의 설계변수인 충돌각, 오리피스 직경비 및 운동량비가 질량분포 및 혼합성능에 미치는 영향을 규명하기 위하여, 추진제대용으로 물과 TCE를 사용하는 비연소시험법에 의해서 수행되었다.