• Nuclear Engineering and Technology
• /
• 제33권6호
• /
• pp.585-595
• /
• 2001

A series of experiments have been carried out to investigate the effects of non-condensable gas on the direct contact film condensation of vapor mixture under an adiabatic wall condition. The average heat transfer coefficient of the direct contact condensation was obtained at the atmospheric pressure with four main parameters ; air-mass fraction, mixture velocity, film Reynolds number, and the degree of water film subcooling having an influence on the condensation heat transfer coefficient. With the analysis of 88 experiments, a correlation of the average Nusselt number for direct contact film condensation of steam/air mixture at an adiabatic vertical wall was proposed as functions of film Reynolds number, mixture Reynolds number, air mass fraction, and Jacob number. The average heat transfer coefficient for steam/air mixture condensation decreased significantly while air mass fraction increased. The average heat transfer coefficients also decreased as the Jacob number increased, and were scarcely affected by the film Reynolds number below a mixture Reynolds number of about 245,000.

• 대한화학회지
• /
• 제51권1호
• /
• pp.93-100
• /
• 2007

이 연구의 목적은 중학교 과학 교과서에 제시된 ‘철과 황의 혼합물과 화합물 성질 비교 실험'의 문제점을 분석하고 개선책을 제시하는 것이다. 이를 위하여 9학년 과학 교과서에 제시된 실험 방법을 분석하고, 교과서에 제시된 실험 방법에 따라 중학교 과학을 담당하고 있는 40명의 현직 교사에게 실험을 수행하게 한 후 문제점을 분석하였다. 자극적인 기체 발생으로 인한 거부감, 자성 비교를 이용한 혼합물과 화합물의 구별 실패 등의 문제점이 개선된 개선 실험과 대안실험을 제시하였다. 제안된 2가지 실험을 10명의 현직 화학 교사와 S중학교 3학년 60명에게 적용한 결과, 제안된 실험은 혼합물과 화합물의 특성 비교에 적합하며 개념 이해에 도움이 된다고 응답하였다.

• 산업기술연구
• /
• 제22권A호
• /
• pp.83-87
• /
• 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.

• 대한산업공학회지
• /
• 제33권3호
• /
• pp.349-354
• /
• 2007

A mixture experiment is a special type of the response surface experiment in which the factors are the components of a mixture, and the response variable is a function of the proportions of each component. When a new mixture product is developed, there are a large number of components, and the first objective of the experiment is to identify the ones that are most important by doing a screening experiment. We propose a method of screening mixture components using the correlation coefficients when t-tests cannot identify significant components.

• 응용통계연구
• /
• 제19권2호
• /
• pp.339-347
• /
• 2006

혼합물실험에서 제한된 영역 때문에 공선성문제가 발생하면 회귀계수에 대한 추정값이 매우 불안정하게 되므로 이를 해결하기 위하여 우리는 주로 능형추정량을 사용한다. 이 때 붓스트랩 기법을 사용하면 능형추정량에 대한 붓스트랩 신뢰구간을 구할 수 있다. 본 논문에서는 제한된 영역을 갖는 혼합물실험의 한 예를 통하여 붓스트랩 잔차 방법과 붓스트랩 쌍 방법 각각에 대하여 능형회귀추정량에 대한 붓스트랩 신뢰구간을 구하고 서로 비교하였다.

• Journal of the Korean Statistical Society
• /
• 제11권1호
• /
• pp.36-44
• /
• 1982

A new design concept, called axis-slope-rotatability, is presented for the design of experiments with mixtures. This is an analogue of the Box-Hunter (1957) rotatability for second order response surface designs. By choice of design, it is possible to make the variance of the estimated slopes along the component axes constant for all axial points equidistant from the center point of the factor space. This property is called axis-slope-rotatability for mixture experiments. When the Scheffe's second degree polynomial is used, it is shown that some symmetry conditions are sufficient for axis-slope-rotatability. Several designs having this property are illustrated.

• 품질경영학회지
• /
• 제40권3호
• /
• pp.347-358
• /
• 2012

Purpose: Given the mixture components - process variables experimental data, we propose the strategy to find the proper combined model. Methods: Process variables are factors in an experiment that are not mixture components but could affect the blending properties of the mixture ingredients. For example, the effectiveness of an etching solution which is measured as an etch rate is not only a function of the proportions of the three acids that are combined to form the mixture, but also depends on the temperature of the solution and the agitation rate. Efficient designs for the mixture components - process variables experiments depend on the mixture components - process variables model which is called a combined model. We often use the product model between the canonical polynomial model for the mixture and process variables model as a combined model. Results: First we choose the reasonable starting models among the class of admissible product models and practical combined models suggested by Lim(2011) based on the model selection criteria and then, search for candidate models which are subset models of the starting model by the sequential variables selection method or all possible regressions procedure. Conclusion: Good candidate models are screened by the evaluation of model selection criteria and checking the residual plots for the validity of the model assumption. The strategy to find the proper combined model is illustrated with examples in this paper.

• 산업공학
• /
• 제18권4호
• /
• pp.402-411
• /
• 2005

Secondary batteries with high performance are essential in widespread use of modern portable devices such as cellular phones and laptop computers. High energy density, long cycle life, and safety are some of important requirements for secondary battery. To achieve such characteristics, a mixing proportion of electrolyte solution ingredients in the battery should be carefully chosen. In this paper, using statistical design of mixture experiments (DOME), we attempt to find an optimum condition of designing the secondary battery. DOME has a distinct feature in that the experimental region is represented by simplex, rather than hypercube, because the sum of blend proportions should be unity. Several designs based upon this point have been proposed for mixture experiments. Among them, an extreme vertices design is employed in this paper because there are a couple of blend constraints to be considered. In order to investigate how the mixing proportion interacts with other manufacturing factors, a fractional factorial design is also included across the extreme vertices design. As a result, we find that the blend proportion of solution ingredients has a significant effect on battery performances. By simultaneously optimizing two battery capacities, this paper proposes an optimum blend proportion according to process factor settings.

• Journal of Animal Science and Technology
• /
• 제51권1호
• /
• pp.15-24
• /
• 2009

본 연구는 다양한 유기산제들의 급여가 이유자돈의 성장과 영양소 소화율에 미치는 영향을 비교하기 위하여 2번의 사양실험을 수행하였다. 실험 1과 실험 2에서는 각각 이유자돈 180두 (4처리, 3반복, 15두/반복)를 공시하였다. 실험 1은 기초사료에 formic acid, ammonium-formate, lactic acid 그리고 acid mixture를 각각 0.5%씩 첨가하여 총 5주간 사양실험을 실시하였으며, 실험 2는 formic acid, ammonium-formate, lactic acid 그리고 acid mixture를 각각 0.3%씩 첨가하여 총 6주간 사양실험을 실시하였다. Acid mixture는 formic acid와 lactic acid가 50:50의 비율로 혼합된 제제를 사용하였다. 외관상 회장아미노산 소화율을 측정하기 위하여 각 처리별 3두, 총 12두를 공시하여 T-cannula를 회장 말단부에 부착시킨 후 적응기간을 거쳐 회장내용물을 채취하였다. 사양성적은 유기산 종류에 따른 개선 효과는 없는 것으로 나타났으나 (실험 1), acid mixture 급여구에서 증체량이 lactic acid 급여구보다 높은 것으로 나타났다 (실험 2). 외관상 회장 아미노산 소화율은 lactic acid 급여구보다 acid mixture 급여구에서 개선되는 것으로 나타났다 (실험 1과 2). 실험 1과 2의 결과를 종합하였을 때 acid mixture (formic acid + lactic acid) 급여는 이유자돈의 사양성적과 외관상 회장 아미노산 소화율을 개선시키는 것으로 판단된다.

• Communications for Statistical Applications and Methods
• /
• 제21권2호
• /
• pp.161-168
• /
• 2014

In mixture experiments with process variables, we consider the case that some of process variables are either uncontrollable or hard to control, which are called noise variables. Given the such mixture experimental data with process variables, first we study how to search for candidate models. Good candidate models are screened by the sequential variables selection method and checking the residual plots for the validity of the model assumption. Two methods, which use numerical optimization methods proposed by Derringer and Suich (1980) and minimization of the weighted expected loss, are proposed to find a cost-effective robust optimal condition in which the performance of the mean as well as the variance of the response for each of the candidate models is well-behaved under the cost restriction of the mixture. The proposed methods are illustrated with the well known fish patties texture example described by Cornell (2002).