• 대한기계학회논문집
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• 제18권8호
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• pp.2194-2200
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• 1994

In an automotive spark ignition engine, it is important to form the proper mixture (air/fuel) on each driving condition for developing the stabilizing combustion and exhaust characteristics. Since most of supply fuel si attached on the inside wall of the intake manifold for unadequate nonuniformity of fuel distribution to each cylinder and mixture variation. Also it affects engine performance variation and causes noises and vibration. In this study, we verified the effect of the mixture variation which is caused by fuel liquid film in the intake manifold on combustion characteristics and engine performance.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2009년도 추계학술대회
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• pp.15-22
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• 2009

Quality variations in mixture products such as medicine, food, engineering chemicals, and alloy materials can be caused by their own sub-components. For instance, discharging characteristics of a lithium-ion rechargeable battery depend upon the mixture ratio of ethylene, dimethyle, and ethyle-methyle, all of which consists an electrolyte solution in the battery. Thus it is important to determine tolerances of mixture components in maintaining the product quality at a desired level. This paper proposes a simple but efficient approach to a mixture tolerancing method with multi-response variables. We use a response surface method for empirical modelling between mixture components. An illustrative example of the proposed method is given.

• 한국축산식품학회지
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• 제39권2호
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• pp.345-353
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• 2019

Various commercial collagen mixtures aimed at improving the quality of meat products are available, but the optimal composition is unclear. This study aimed to compare the functional properties, including physicochemical characteristics and lipid oxidative stability, of loin ham marinated with three commercial collagen mixtures sold as food additives. The addition of collagen mixtures led to significant increases in the moisture content, water holding capacity (WHC), cooking yield, and instrumental tenderness, regardless of the type of collagen mixture. In particular, meat samples containing collagen mixture C showed the highest (p<0.05) WHC and tenderness among all groups. Furthermore, collagen mixture B induced increases (p<0.05) in pH values in both raw and cooked samples. The $a^*$ values of samples with collagen mixtures were lower (p<0.05) than those of samples without collagen mixtures. All collagen mixtures effectively improved oxidative stability during 7 days of storage at $4^{\circ}C$. The samples containing collagen mixture B had the lowest lipid oxidation (p<0.05) among groups. These results indicated that collagen mixture C could be used in injection brine to enhance the quality characteristics of meat products, particularly the WHC and tenderness. Collagen mixture A could be used for meat products with high fat contents based on its ability to improve lipid oxidative stability during long-term storage.

• 한국자동차공학회논문집
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• 제4권4호
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• pp.201-209
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• 1996

This study describes the combustion characteristics of methance-air mixture with various equivalence retio and initial conditions of mixture in constant volume combustion chamber. Combustion characteristics of methane-air mixture such as combustion pressure, combustion temperature, and heat release were investigated by the measurement of combustion pressure and temperature in the combustion chamber. The results show that maximum combustion pressure, gas temperature and rate of heat release have peaks at equivalence ratio of 1.1. Combustion duration is also the shortest at the equivalence ratio of 1.1 and it is shortened as initial mixture temperature increases.

• 한국자동차공학회논문집
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• 제2권4호
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• pp.72-79
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• 1994

In an automotive spark ignition, it is important to form the proper mixture(air/fuel) on each driving condition for developing the stabilizing combustion and exhaust characteristics. Since most of supply fuel is attached on the inside wall of the intake manifold for unadequate atomization by fuel injection system, it brings a bad effect on combustion and exhaust caused by nonuniformity of fuel distribution to each cylinder and mixture variation. Also it affects engine performance variation and causes noises and vibration. In this study, we verified the effect of the mixture variation which is caused by fuel liquid film in an intake manifold on combustion characteristics and engine performance.

• 산업기술연구
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• 제22권A호
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• pp.83-87
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• 2002

Many industrial products such as paints, ink and adhesives are composed of the ingredients of a mixture. In mixture experiments, the characteristics of quality(response) depends only on the proportions of the ingredients and does not depend on the total amount of the mixture. This article discusses the constrained mixture experimental design, the data analysis, and the optimum formulation of ingredients based on the two quality characteristics - taste and flavor. It IS shown that efficient designs can be constructed from D-optimal criterion. Special cubic models were selected as the final mixture response surfaces for both reponses. The desirability function was used for the optimization of the two responses.

• 품질경영학회지
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• 제38권4호
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• pp.580-586
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• 2010

Performance variations in mixture products such as medicine, food, and chemicals can be caused by their own subcomponents. For instance, a discharge capacity of a lithium-ion battery depends upon the mixture ratio of ethylene, dimethyle, and ethyle-methyle, all of which are subcomponents of an electrolyte solution in the battery. Thus it is crucial to determine tolerances of the mixture ratio in order to maintain the product quality at a desired level. This paper is concerned with the tolerance design of the mixture ratio. In particular, minimizing variance around the mixture ratio is adopted as a decision criterion in this paper. An illustrative example with multiple quality characteristics is given as well.

• 한국기계가공학회지
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• 제8권3호
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• pp.13-20
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• 2009

Development of a dynamic engine model is essential to predict and analyze of dynamic characteristics from a natural gas engine. Reducing the harmful exhaust emissions can be accomplished by a precise air-fuel ratio control. In this paper, the dynamic engine model was proposed and included mixture formation and intake process because the dynamic characteristics can be affected by the mixture components such as an air and a gaseous fuel. The air mass flow, the partial pressure ratio, and the gas constant are changed by variations of the components in the mixture formation and intake process. The dynamic engine model is applied to the natural gas engine for validation test. Experimental results show that the dynamic engine model is effective to predict the dynamic characteristics of the natural gas engine.

• 한국연소학회지
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• 제1권2호
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• pp.21-29
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• 1996

Flame propagation characteristics of propane-air mixtures were experimentally investigated in constant-volume combustion chambers. Flame propagation process was observed as a function of mixture strength, initial mixture temperature and initial mixture pressure in quiescent mixtures. A cylindrical combustion chamber and a spherical combustion chamber contain a pair of parallel windows through which optical access into the chamber can be provided. Laser two beam deflection method was adopted to measure the local flame propagation, which gave information on the flame size and flame propagation speed. Pressure development was also measured by a piezoelectric pressure transducer to characterize combustion in quiescent mixtures. Burning velocity was calculated from flame propagation and pressure measurements. The effect of flow on flame propagation was also investigated under flowing mixture conditions. Laser two beam method was found to be feasible in measuring flame propagation of quiescent mixtures. Flame was observed to propagate faster with higher initial mixture temperature and lower initial pressure. Combustion duration was shortened in the highly turbulent flowing mixtures.

• International Journal of Automotive Technology
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• 제6권2호
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• pp.79-85
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• 2005

This work is to investigate the surface heat flux and combustion characteristics of premixed propane mixture in a constant volume chamber. The experiment of heat flux and combustion characteristics of premixed propane mixture are performed with various equivalence ratio and initial pressure conditions. Based on the experimental results, it is found that the maximum instantaneous temperature is increased with the increase of initial pressure in the chamber. There are significant differences in the burning velocity of premixed propane mixture at different measuring points in the constant volume combustion chamber. A]so, the trends of temperature difference at each measuring points are similar to the burning velocity in the combustion chamber. It is concluded that the total heat loss during the combustion period is affected by the equivalence ratio and the initial condition of fuel-air mixture.