• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.11a
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• pp.56-61
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• 1995

균일한 속도를 갖는 주유동장에 연료를 분사하였을때 분사된 연료가 주유동장의 공기와 혼합되는 정도를 정량적으로 설명하기 위하여 실험과 수치 계산을 실시하였다. 본 연구에서는 혼합 진전 정도를 나타내기 위하여 혼합진전변수(mixing progress variable)를 도입하여 유동조건에 따라 혼합 정도를 정량적으로 비교하였다. 주유동 속도가 일정할때 분사 속도를 증가시키면 연료가 주유동장의 공기와 혼합이 촉진됨을 알 수 있었다.

• Membrane Journal
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• v.11 no.4
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• pp.161-169
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• 2001

Single and mixed particle suspensions of kaolin, bentonite, starch and PMMA were carried out using a dead-end Amicon fi1tration cell with microfilteration membranes. The experimental data of permeate fluxes were fitted by the constant pressure fi1tration models in order to investigate fouling steps. In 0.1 wt% mixed solution of equal amount of kaolin and starch, the permeation flux was about 30% lower than the average of each particle flux. However, the permeation flux for kaolin/PMMA mixed solution was about 10% higher than the average of each particle flux. In the cases of bentonite and PMMA or starch mired solution, the improvement effect on permeation flux was weaken than that of kaolin mixed solution. Also, the membrane fouling resistance for mixed particle solution of equal amount of kaolin and starch was minimum at 0.05 wt% particle concentration.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.2
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• pp.127-132
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• 1984

Performance tests of small diesel engine were carried out, using the blend fuel oil as the substitute fuel oil and the following results were obtained. (1) The character at the blend oil as substitute fuel for small diesel engine was examined. (2) In the case of operating small diesel engine with blend oil, the exhaust gas volume increases at 8% in comparison with diesel oil. (3) In the case of operating small diesel engine with blend oil, the fuel consumption Increases at 3% in comparison with diesel oil. (4) In the brake thermal efficiency, blend oil is similar to diesel oil.

• Journal of the Korean Geotechnical Society
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• v.29 no.6
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• pp.53-62
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• 2013

A 5-20 cm thick shocrete has been routinely constructed for NATM tunneling method to stabilize and confine the excavated rock of tunnel construction site. A $40kg/m^3$ of steel fibers are usually mixed into such shotcrete but these steel fibers may not be evenly distributed depending on shotcrete machines, mixing ratios and excavated rock conditions. In this study, square column shotcrete-mimicked concrete specimens of $15cm{\times}15cm{\times}55cm$ were prepared with 5 equal layers and 5 or 20% cement ratio. The specimens were prepared with different reinforced-patterns: non-reinforced, middle layer-reinforced, 1, 3, and 5 layers-reinforced, or all layers reinforced. The specimens were air-cured for 7 days and tested for flexural strength. The influence of steel-fiber distribution on flexural strength and toughness of shotcrete-mimicked concrete specimens was investigated. In the case of a specimen with cement ratio of 20%, a flexural strength increased as a number of fiber-reinforced layer increased. The flexural strength of one-layer reinforced specimen showed 20% less than that of evenly fiber-distributed specimen. On the other hand, a specimen with cement ratio of 5% decreased as the number of fiber-reinforced layers increased. A toughness index increased as the number of fiber-reinforced layers increased, regardless of cement ratios. The toughness index of evenly fiber-distributed specimen showed 2-3 times as large as that of one-layer reinforced specimen.

• Journal of the Korean Geotechnical Society
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• v.16 no.2
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• pp.125-134
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• 2000

지반이 산업용 기름으로 오염될 때 지반의 강도변화 특성을 연구하기 위하여 모래와 실트질 모래 및 카오리나이트를 대상으로 함수비아 함유비를 변화시키며 다짐실험, 투수실험, 비배수상태에서 삼축압축실험을 실시하였다. 실험결과에 의하면 밀도가 같은 모래의 경우는 기름을 혼합하였을 경우가 물을 혼합하였을 경우에 비해 약 7%정도 전단 강도가 떨어지고 실트질 모래와 카오리나이트 경우는 기름을 혼합하였을 경우가 물을 혼합하였을 경우에 비해 점토입자와 기름의 화학적, 물리학적인 상호 작용으로 5~15%정도 강도가 증가하는 현상을 보였다. 일반적으로 산업용 기름 유출에 따라 토양오염 및 수질오염으로 동.식물에 큰 영향을 주고 있으나 토질역학적 거동은 초기 상태 및 모래에서는 전단 강도가 감소하였으나 점성토의 경우는 기름 유출 또는 유입에 따라 응집성, 부착성이 생겨 강도증가 현상을 가져와 큰 문제점이 없는 것으로 판단된다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.19 no.1
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• pp.85-107
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• 1993

The cosmetic fine powders were mixed with variation of mixing time(5) in the mixers (ribbon mixer, powder mixer, micropulverizer and fine impact mill). The powders were nixed with small amount of ferric oxide. as tracer. The mixed powders ere measured the particle size distribution, specific surface area and surface color with mixing time (s). The color variation, particle size distribution and specific surface area of the mixed powder exist a relationship with mining time(s) that can be expressed as mathematical equations to show the degree of the mixing of the powder mixture. The linear velocity of the impellar tip is the main factor contributing to he mixing efficiency of the mixers un this study. According to the linear velocity, he mixers used are devieded as convection mixing (ribbon mixer), sclera mixing powder mixer) and diffusion mixing (micropulverizer/fine impact mill).

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.437-444
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• 2005

Experiments were carried out in an atmospheric pressure, lab-scale gas turbine combustor to see the effect of partial premixing on unstable flame structure and Nox emission characteristics. The swirl angle is 45 deg., fuel-air mixing degrees were varied 0, 50 and 100% respectively at equivalence ratio ranging from 0.53 to 0.79. The evolution of phased-locked OH chemiluminescence images were acquired with an ICCD. NOx emission characteristics were also investigated at each experimental condition. The effect of the fuel-air mixing degree on the flame structure was obtained from phase-locked $OH^*$ images. And it was obtained from local heat release characteristics that the information about the region which the combustion instability was amplified or damped. It also could be confirmed that $\sigma$ has greatly influence on NOx emission characteristics at lean regimes. It would be expected that it could provide invaluable data for understanding the mechanism of combustion instability.

• Korean journal of food and cookery science
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• v.3 no.2
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• pp.59-67
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• 1987

In order to make use of Job's tears widely, Job's tears starch was analyzed and determinded the contents of amylose, amylographical and other physicochemical properties. And also the yeast breads and rice cakes were made from flour and rice flours with various mixing ratios of Job's tears flour and then they were tested for suitability to preparation of bread and rice cake. 1. The starch contents of Job's tears showed 12~20%. Which was about one third of rice or waxyrice starch. But amounts of crude proteins, fats, and total ashes in Job's tears were higher than rice or waxyrice. Job' tears starch was composed of amylopectins only, and was similar to that of waxyrice starch. 2. Depends upon the Amylogram of each starch, initial gelatinization temperature of Job's tears starch was the highest among three starches of rice, waxyrice, and Job's tears. Maximum viscosity of Job's tears starch was 860BU, then it was about two times of rice starch viscosity. 3. By the sensory evaluation results, the taste of bread prepared with mixing of 10% Job's tears flour was better than flour bread and the volume and grains of the bread made from mixing of 10%, 20% Job's tears flour were similar to that of flour bread, but the taste, volume and grains of bread made from 30% mixed flour were undesirable. The rice cake Prepared from mixed flour with 25% Job's tears flour has shown to be desirable.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1502-1504
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• 2006

본 연구는 $SF_6$와 Dry-air(건조공기)가 혼합된 절연매체의 절연 특성과 부분방전 특성 연구를 위하여 기초실험용 쳄버와 70kV급 GIS mock up 을 이용하여 교류전압을 인가하여 실험이 수행되었다. 전자의 경우, Sphere gap 및 Needle/Plate 전극시스템을 이용하여 순수 $SF_6$가스와 Dry-air의 절연내력을 비교하고, 챔버의 압력을 5기압으로 유지한 상태에서 Dry-air와 $SF_6$가스의 혼합비를 변화시키면서 절연내력이 측정되었다. 후자의 경우, 기초실험에서 도출된 $SF_6$가스와 Dry-air의 최적의 혼합비율을 선택한 후, 방전 개시전압과 부분방전 양상을 순수 $SF_6$가스의 결과와 비교 분석하기 위한 실험을 수행하였다. 이를 위하여 GIS 사고의 주요원인이 되는 결함들, 즉 Protrusion, Floating, Free moving particle 들을 인위적으로 모의하여 Mock up 내부에 설치하고 내부 압력을 5기압으로 유지한 상태에서 수행되었다. 전자의 경우, $0.5{\sim}5$ 기압 범위내 에서 Dry-air 압력을 변화시켰을 때 절연내력은 전극시스템에 무관하게 순수 $SF_6$가스의 결과치의 $40{\sim}50%$정도이다. 또한 챔버 압력이 5기압일 경우, Needle/Plate 전극을 이용했을 경우, Dry-air 가 80% 혼합된 절연매체는 순수 $SF_6$가스 절연내력의 80%정도이다. 후자의 경우, 인가전압을 고정 시켰을 때, 부분방전 패턴과 방전크기는, 순수 $SF_6$가스와 Dry-air 가 80% 혼합된 절연매체는 동일한 패턴과 방전크기를 나타내고 있다. 이러한 결과를 근거로, 가스 압력이 5기압에서 운전되는 전력기기의 절연 매체로서 혼합가스를 사용할 경우, $SF_6$가스와 Dry-air의 혼합비는 2:8정도가 적절한 것으로 제안한다.

• Magazine of the Korea Concrete Institute
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• v.10 no.2
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• pp.155-165
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• 1998

굳지 않은 콘크리트의 슬럼프손실을 저감시키기 위한 목적으로 고로슬래그 미분말 및 플라이애쉬의 혼합비율과 혼화제의 첨가방법을 변화시킨 콘크리트의 믹싱후 경과시간에 따른 슬럼프 변화에 대하여 고찰하였다. 연구결과 보통포틀랜드시멘트에 고로슬래그 비분말 또는 플라이애쉬를 혼합한 콘크리트가 혼화재를 혼합하지 않은 콘크리트보다 슬럼프손실을 줄일 수 있었으며, 고로슬래그 미분말과 플라이애쉬를 각각 50 및 5%를 혼합한 3성분계 콘크리트의 경우 슬럼프손실을 저감시키는데 유효하였다. 또한 혼화제의 일부를 15분후 분할하여 후첨가하는 혼합방법이 굳지않은 콘크리트의 슬럼프손실을 저감시키는데 가장 큰 효과가 있다. 한편 혼화재를 혼합한 3성분계 보통강도용 및 고강도용 콘크리트의 재령 28일까지의 압축강도는 혼화재를 혼합하지 않은 콘크리트보다 작았으나 재령 91일 압축강도는 31% 및 15%정도 크게 증가하였다.