• 한국공작기계학회논문집
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• 제12권5호
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• pp.80-87
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• 2003

Air partial pressure ratio and inlet air mass flow are influenced by water vapor and gaseous fuel in mixture on Compressed Natural Gas (CNG) engines. In this paper, the effects of the water vapor and the gaseous fuel that change the air mass flow and the air-fuel ratio are studied. Effective air mass ratio is defined as the air mass flow divided by mixture mass flow, and also it is applied to the estimation of the inlet air mass flow and the air-fuel ratio. The presence of the gaseous fuel and the water vapor in the mixture reduces the air partial pressure and the effective air mass ratio of the CNG engines. The experimental results for the CNG engine show that estimation of the air-fuel ratio based upon the effective air mass ratio is more accurate than that of a normal mode.

• International Journal of Precision Engineering and Manufacturing
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• 제1권1호
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• pp.33-41
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• 2000

Fiber reinforced metal laminates(FRMLs) were new type of hybrid materials. FRMLs consist of high strength metals(Al 5052-H34) and laminated fiber with structural adhesive bond. The effect of resin mixture ratios on the fatigue crack propagation behavior and mechanical properties of aramid fiber reinforced aluminum composites was investigated. The epoxy, diglycidylether of bisphenol A(DGEBA), was cured with methylene dianiline(MDA) with or without an accelerator(K-54). Eight kinds of resin mixture ratio were used for the experiment ; five kinds of FRMLs(1)(mixture of epoxy and curing agent) and three kinds of FRMLs(2)mixture of epoxy, curing agent and accelerator). The characteristic of fatigue crack propagation behavior and mechanical properties FRMLs(2) shows more effecting than that of FRMLs(1).

• 한국식품과학회지
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• 제45권4호
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• pp.473-477
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• 2013

혼합디자인에 의해 설정된 조건하에서 압출성형한 율무와 밀가루의 압출성형물은 율무 첨가에 대해 여러 반응 요인들이 압출성형물의 특성에 영향을 끼치는 것으로 나타났다. 실험조건은 율무 함량 5-75%, 밀가루 25-95%로 결정하였으며, 수분함량은 20.55%로 고정하여 modified distance based mixture design으로 실험설계 및 분석하였다. Bending 파손강도, WAI, a값 등은 유의성이 없는 것으로 나타났으나, 팽화물의 직경, WSI, L값, b값은 율무와 밀가루의 혼합에 의해 유의성이 존재하는 것으로 나타났다. 팽화물의 직경, L값, b값은 선형 모델로 분석할 수 있었으나 WSI는 quadratic 모델로만 설정이 가능한 것으로 나타났다. 율무의 함량이 많아질수록 외관적으로 팽창되어지는 정도가 적어졌으며, 색상도 어두워지는 것으로 나타났다. 율무의 함량이 증가할수록 L값은 77.84에서 72.73, a값은 1.37에서 1.77로, b값은 19.42에서 17.64로 이동되었다. WSI는 율무와 밀가루가 40%:60%로 혼합되어 압출성형되었을 때 가장 낮게 나타났으며, WAI는 율무와 밀가루 혼합 비율에 대해서는 유의성이 없는 것으로 나타났다. 혼합디자인 계획법은 시리얼류 제품 생산에 적합한 조직 형성과 반응량에 유의한 영향을 미치는 요인 등에 대해 적절한 혼합 비율과 가공 조건 등을 제시할 수 있음을 알 수 있었다. Modified distance based mixture design에 의해, 일반 시중 제품과 유사한 조직감을 나타낼 수 있는 율무와 밀가루, 물의 적정 배합 비율은 60.12:19.42:20.46으로 나타났다.

• 대한기계학회논문집A
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• 제25권4호
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• pp.592-601
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• 2001

Fiber reinforced metal laminates(FRMLs) are new types of hybrid materials. FRMLs consists of high strength metal(Al 5052-H34) and laminated fiber with structural adhesive bond. The mixture ratio effect of epoxy resin$.$curing agent$.$accelerator on the fatigue behavior of FRMLs was investigated in this study. The epoxy, diglycidylether of bisphenol A(DGEBA), was cured by methylene dianiline(MDA) with or without an accelerator(K-54). Eight different kinds of resin mixture ratios were selected for the test ; five kinds of FRMLs(1) and three others of FRMLs(2). The relationship between da/dN and ΔK with variation of resin mixture ratio was studied. FRMLs(1) and FRMLs(2) indicated approximately 2 times and 2.2 times more improved maximum bending strengths in comparison with those of Al 5052-H34. The resin mixture ratio <1:1> in case of FRMLs(1) indicated the maximum fatigue life, while the resin mixture ratio <1:1:0.2> in case of FRMLs(2) indicated the maximum fatigue life. As results, FRMLs(2) turned out to have more effective characteristics on the fatigue properties and the bending strength than those of FRMLs(1).

• KIEAE Journal
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• 제10권3호
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• pp.11-16
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• 2010

This paper has attempted to investigate the change in soil moisture volume and temperature of architecture by planting ground(soil thickness and soil mixture ratio) and ground cover plants(Sedum sarmentosum, Zoysia japonica, Chrysanthemum zawadskii) for middle region green roof system. For this, a test was conducted on the roof of Konkuk University building from April 2009 to October 2009. In terms of treatment, five types(SL, $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$, $P_4P_4L_2$) depending on soil mixture ratio and two types(15cm, 25cm) by soil depth were created. Results of soil moisture volume by soil mixture ratio in the 15cm soil thickness showed that the difference was significance between simple soil and mixture soil treatment, however, the statistical significance was not recognized according to soil mixture ratio. In case of 25cm soil thickness, soil moisture volume by soil mixture ratio was more higher 7Vol.%~10Vol.% in the mixture soil than simple soil treatment. In terms of districts planted ground cover plants, soil volume moisture differed among plants in the order Zoysia japonica 17.74 Vol.%$34.86^{\circ}C$, district non-planted $27.49^{\circ}C$, Sedum sarmentosum $25.11^{\circ}C$, Chrysanthemum zawadskii $23.08^{\circ}C$, Zoysia japonica $24.45^{\circ}C$ respectively So, concrete surface showed more higher $5^{\circ}C{\sim}15^{\circ}C$ than other things among the all the time. Result of inner temperature of the architecture and soil, it was measured inner of architecture $25.69^{\circ}C$, inner district non-planted $24.29^{\circ}C$, Chrysanthemum zawadskii $23.90^{\circ}C$, Zoysia japonica $24.02^{\circ}C$, Sedum sarmentosum $25.13^{\circ}C$, respectively.

• Korean Chemical Engineering Research
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• 제51권6호
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• pp.677-684
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• 2013

혼합냉매를 사용하여 천연가스를 액화하는 혼합냉매공정(Mixed refrigerant cycle, MRC)은 공정이 간단하고 장치비가 적게 들며 운전 또한 용이하여 널리 채택되고 있는 공정이다. MRC에서 중요한 기술 중 하나는 혼합냉매를 선택하고 최적의 혼합비를 결정하는 것이다. 본 연구에서는 일반적인 MRC에서 혼합냉매와 혼합냉매의 혼합비가 공정의 성능에 미치는 효과를 살펴보았다. 이를 위해 통계적 기법 중 실험계획법의 하나인 혼합물 설계와 반응 표면법을 이용하여 전체 공정의 에너지 소비가 최소가 되게 하는 최적의 냉매를 선택하고 그 혼합비를 결정하였다. 여러 냉매와 혼합비에 따른 MRC 공정의 모사는 Aspen HYSYS를 사용하였으며 혼합물설계와 반응 표면법은 Minitab을 사용하였다. 연구결과 냉매로는 methane ($C_1$), ethane ($C_2$), propane ($C_3$)과 nitrogen ($N_2$)가 선택되었으며 에너지 소비를 최소화하는 혼합비(몰 비) 또한 구할 수 있었다.

• 대한기계학회논문집B
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• 제26권2호
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• pp.318-327
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• 2002

In this paper, heat transfer and pressure oscillation characteristics on oscillating capillary tube heat pipe(OCHP) according to input heat flux, mixture ratio of working fluid and inclination angle were investigated and were compared single working fluid(R-142b) with binary mixture working fluid(R-142b-Ethano1). OCHP was made to serpentine structure of loop type with 10 turns by drilling the channels of length 220mm, width 1.5mm, and depth 1.5mm on the surface of brass plate. In this study, R-l42b and R-l42b-Ethanol were used as working fluids, the charging ratio of working fluids was 40(vol.%), the input heat flux to evaporating section was changed from 0.3W/㎠ to 1.8W/㎠, and mixture ratio of working fluid was R(100%), R(95%)-E(5%), R(90%)-E(10%), and R(85%)-E(15%). From the experimental results, it was found that the effective thermal conductivity of single working fluid was better than that of binary mixture working fluid. But, in case of binary mixture working fluid, critical heat flux was higher than that of single working fluid. And, the higher the mixture ratios of working fluid, the lower heat transfer performance. In case of pressure oscillation, as the inclination angle was lower, pressure wave was more irregular. These phenomena were more serious when the working fluid was binary mixture. Besides, when mixture ratio was higher, saturated pressure was increased, more irregular wave was observed and the mean amplitude was increased. For the same input heat flux, inclination angle and charging ratio, when pressure oscillation has sinusoidal wave, mean amplitude was small, and saturated pressure was low value, the heat transfer was excellent.

• 대한기계학회논문집B
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• 제25권10호
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• pp.1311-1317
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• 2001

To investigate only the effects of the stratified mixture distribution on initial flame propagation and combustion characteristics, the instantaneous equivalence ratio in the spark plug gap and combustion pressure were measured simultaneously In a constant volume chamber, To induce the stratified propane-air mixture distribution near the spark plug, counter-flow typed mixture injection system was used under the constant mean equivalence ratio $\Phi$$\_$mean/= 1.0 The instantaneous equivalence ratio was measured by a single-shot Raman scattering with narrow-band KrF excimer laser. The measuring error was within the limit of $\pm$ 3.5% provided that the proposed method was applied to the measured Raman signals. Judging from mass fraction burned derived from the measured pressure, the optimum combustion characteristics were shown under the condition that the local equivalence ratio in the spark plug was near 1.28$\pm$0.04, and these characteristics were more remarkable at the initial stage of combustion.

• 통합자연과학논문집
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• 제14권3호
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• pp.99-106
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• 2021

A mixture of alcohol and water is commonly used as antifreeze, liquor, and the fundamental solvents for the manufacture of cosmetics, pharmaceuticals, and inks in our daily life. Since various properties of alcohol water mixtures such as density, boiling or melting point, viscosity, and dielectric constant are determined by their mixing ratio, it is very important to know the mixing ratio to predict their properties. One of simple method to find the mixing ratio is measuring the density of the mixtures. However, it is not easy to predict the mixing ratio from the density of the mixtures because the relationship between mixing ratio and density has not been established well. The relationship is dependent on the relative sizes of solute and solvent molecules, and their interactions. Recently, an empirical model to predict the density of glycerol water mixture from their mixing ratio has been introduced. The suggested model is simple but quite accurate for glycerol water mixture. In this article, we investigated the applicability of this model to different alcohol water mixtures. Densities for six different alcohol water mixtures containing various alcohols (e.g., ethylene glycol, 1,3-propane diol, propylene glycol, methanol, ethanol, and 1-propanol) were simulated and compared to experimentally measured ones to investigate the applicability of the model proposed for glycerol water mixtures to other alcohol water mixtures. The model predicted the actual density of all alcohol water mixtures tested in this article with high accuracy at various ratios. This model can probably be used to predict the mixing ratio of other alcohol water mixtures from their densities beyond 6 alcohols tested in this article from their densities.

• 한국환경과학회지
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• 제25권5호
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• pp.625-633
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• 2016

This study was conducted to investigate the influence of hydrophilic polymer (HP) mixture ratio (Control, 1.0%, 2.5%, 5.0%, and 10.0%) on growth of eggplant (Solanum melongena) for lower maintenance urban agriculture via green roofs. Although it was not statistically significant (p > 0.05), substrate temperature was decreased as hydrophilic polymer mixture ratio were increased. High substrate water content (95%) was found consistently in growing media under elevated hydrophilic polymer mixture ratio at over 5% during the entire growing period. Substrate electronic conductivity was increased as hydrophilic polymer mixture ratio were increased. Growth index was decreased as hydrophilic polymer mixture ratio was increased. It was reduced about 1/3 and 1/5 compared to that of Control in HP5.0 and HP10.0 treatment plants, respectively. Number of leaves, leaf length, and leaf width were decreased in following order: Control> HP1.0> HP2.5> HP5.0> HP10.0 treatments. There numbers were significantly lower in HP5.0 and HP10.0 treatment plants. Dry weight of shoot and root were decreased as hydrophilic polymer mixture ratio was increased. They were reduced by 1/4 compared to those of Control treatment plants. In addition, visual value was decreased as hydrophilic polymer mixture ratio was increased. Plants grown in HP1.0, HP2.5, and HP5.0 treatments all survived. However, plants grown in the HP10.0 treatment had the lowest survival rate (56%) after 3 months of growing. These results indicate that the advantage of adding hydrophilic polymer to green roof growing media may greater during dry periods. However, the proper mixture proportion of hydrophilic polymer should be determined according to different characteristics of growing media and plant species.