• 한국기계가공학회지
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• 제1권1호
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• pp.133-140
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• 2002

The object of this paper is to predict the surface roughness using the experiment equation of surface roughness, which is developed with a full factorial design in turning. $3^3$ full factorial design has been used to study main and interaction effects of main cutting parameters such as cutting speed, feed rate, and depth of cut, on surface roughness. For prediction of surface roughness, the arithmetic average (Ra) is used, and stepwise regression has been used to check the significance of all effects of cutting parameters. Using the result of these, the experimental equation of surface roughness, which consists of significant effects of cutting parameters, has been developed. The coefficient of determination of this equation is 0.9908. And the prediction ability of this equation was verified by additional experiments. The result of that, the coefficient of determination is 0.9718.

• Computers and Concrete
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• 제12권5호
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• pp.651-668
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• 2013

Concrete structures need repairing due to various reasons such as deteriorative effects, overloading, poor quality of workmanship and design failures. Cement based repair mortars are the most widely used solutions for concrete repair applications. Various factors may affect the bond strength between concrete substrate and repair mortars. In this paper, the effects of polymer additives, strength of the concrete substrate, surface roughness, surface wetness and aging on the bond between concrete substrate and repair mortar has been investigated. Full factorial experimental design is employed to investigate the main and interaction effects of these factors on the bond strength. Analysis of variance (ANOVA) under design of experiments (DOE) in Minitab 14 Statistical Software is used for the analysis. Results showed that the interaction bond strength is higher when the application surface is wet and strength of the concrete substrate is comparatively high. According to the results obtained from the analysis, the most effective repair mortar additive in terms of bonding efficiency was styrene butadiene rubber (SBR) within the investigated polymers and test conditions. This bonding ability improvement can be attributed to the self-flowing ability, high flexural strength and comparatively low air content of SBR modified repair mortars. On the other hand, styrene acrylate rubber (SAR) modified mortars was found incompatible with the concrete substrate.

• 반도체디스플레이기술학회지
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• 제12권4호
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• pp.9-13
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• 2013

Lapping is a very complicated and random process resulting from the variation of abrasive grains in its sizes and shapes and from the numerous factors having an effect on the process quality. This paper presents a study of a $2^4$ full factorial experimental design and analysis to optimize surface quality in lapping operation. The optimization of the factors to obtain minimum surface roughness was carried out by incorporating effect plots, main effect plots, interaction plots, analysis of variance(ANOVA), surface plots, and contour plots. The statistical design experiments, designed to reduce the total number of experiments required, indicated that, within the selected conditions, all the parameters influenced at a significance level of 5%. In addition, some of the possible interactions between these parameters also influenced the lapping process, especially those that were of third order. A regression model was suggested and fitted the experimental data very well.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.700-703
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• 2004

A reliability analysis and design procedure based on the design of experiment (DOE) is combined with the response surface method (RSM) for numerical efficiency. The procedure established is based on a 3$^n$ full factorial DOE for numerical quadrature using explicit formula of optimum levels and weights derived for general distributions. The full factorial moment method (FFMM) shows good performance in terms of accuracy and ability to treat non-normally distributed random variables. But, the FFMM becomes very inefficient because the number of function evaluation required increases exponentially as the number of random variables considered increases. To enhance the efficiency, the response surface moment method (RSMM) is proposed. In RSMM, experiments only with high probability are conducted and the rest of data are complemented by a quadratic response surface approximation without mixed terms. The response surface is updated by conducting experiments one by one until the value of failure probability is converged. It is calculated using the Pearson system and the four statistical moments obtained from the experimental data. A measure for checking the relative importance of an experimental point is proposed and named as influence index. During the update of response surface, mixed terms can be added into the formulation.

• Corrosion Science and Technology
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• 제20권2호
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• pp.52-61
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• 2021

This study using experimental design and linear regression technique was implemented in order to predict the pitting potential of stainless steel in marine environments, with the target materials being AL-6XN and STS 316L. The various variables (inputs) which affect stainless steel's pitting potential included the pitting resistance equivalent number (PRNE), temperature, pH, Cl^- concentration, sulfate levels, and nitrate levels. Among them, significant factors affecting pitting potential were chosen through an experimental design method (screening design, full factor design, analysis of variance). The potentiodynamic polarization test was performed based on the experimental design, including significant factor levels. From these testing methods, a total 32 polarization curves were obtained, which were used as training data for the linear regression model. As a result of the model's validation, it showed an acceptable prediction performance, which was statistically significant within the 95% confidence level. The linear regression model based on the full factorial design and ANOVA also showed a high confidence level in the prediction of pitting potential. This study confirmed the possibility to predict the pitting potential of stainless steel according to various variables used with experimental linear regression design.

• Journal of Korean Society for Atmospheric Environment
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• 제24권E2호
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• pp.83-91
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• 2008

This work investigated the methodology to simultaneously optimize the ozone and relative humidity composition for the $NO_x$ degradation using soil biofilter. Experiments were made as a function of inlet ozone concentration ($0{\sim}1,770\;ppb$) and relative humidity ($38{\sim}81%$). Factorial design ($2^2+3$) and response surface methodology by central composite designs were used to examine the role of two factors and optimal response condition on $NO_x$ degradation. It was found that a second-order response surface model can properly interpret the experimental data with an $R^2$-value of 0.9730 and F-value of 71.83, based on which the maximum $NO_x$ degradation was predicted up to 92.8% within our experimental conditions.

• 한국자동차공학회논문집
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• 제23권5호
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• pp.545-552
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• 2015

The heat generation in PEMFC is proportional to the electrical power output. Therefore, when the fuel cell produced the maximum output, the maximum heat was generated. In order to maintain the performance of the fuel cell, thermal management is as important as pressure and humidity conditions of the reactive gas. In this study, considering the thermal management for the maximum output operation, the optimal cooling channel design specifications of bipolar plate are found for the highest cooling performance. In the current bipolar plate research, many studies focused on analyzing various factors individually but there is no more study on the interaction between design factors. In this study, the heat transfer was simulated by COMSOL Multiphysics with the main design factors which are designated shape, width and rib length. One of the experimental design methods, general full factorial design method, was used to analyze the main factor and interaction on average temperature and maximum temperature for the design specification of fuel cell bipolar plate. When analysis result shows that all of these three factors are highly important, it can confirm that the interaction occurs between the factors.

• Environmental Engineering Research
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• 제23권1호
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• pp.36-45
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• 2018

The phosphogypsum (PG) is a byproduct of the phosphate fertilizers manufacture. The world production estimated to 200 million tons per year induces environmental threats and storage problems, which requires strict policies to limit pollution and encourage its valorization. This paper presents a purification process of the crude PG including treatment with a diluted sulfuric acid, floatation, filtration and washing. The purified PG is used to produce plaster. The process optimization was conducted using a full factorial design. The significant factors considered in the experimental study are temperature ($X_1$), volume of sulfuric acid solution ($X_2$) and PG quantity ($X_3$). The main effects and interaction effects of these factors on the responses of the % $P_2O_5$, % F, Total Organic Carbon (TOC) ($mg{\cdot}kg^{-1}$) and pH were analyzed. The optimum conditions for $X_1$, $X_2$ and $X_3$ were found to be $60^{\circ}C$, 3 L and 1 kg, respectively and the optimized pH values was found to be 6.2. Under these conditions, 60% of $P_2O_5$, 95% of Fluorine and 98% of TOC were removed from PG. The predicted values were found approximately the same as the experimental ones. The plaster produced with purified PG was found to have similar properties to that produced from natural gypsum.

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.172-178
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• 2011

This paper presents an optimization procedure for high-efficiency design of a mixed-flow pump. Optimization techniques based on a weighted-average surrogate model are used to optimize a vane diffuser of a mixed-flow pump. Validation of the numerical results is performed through experimental data for head, power and efficiency. Three-level full factorial design is used to generate nine design points within the design space. Three-dimensional Reynoldsaveraged Navier-Stokes equations with the shear stress transport turbulence model are discretized by using finite volume approximation and solved on hexahedral grids to evaluate the efficiency as the objective function. In order to reduce pressure loss in the vane diffuser, two variables defining the straight vane length ratio and the diffusion area ratio are selected as design variables in the present optimization. As the results of the design optimization, the efficiency at the design flow coefficient is improved by 7.05% and the off-design efficiencies are also improved in comparison with the reference design.

• 한국기계가공학회지
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• 제19권6호
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• pp.49-54
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• 2020

The purpose of this study is to investigate the effects of the change in the spindle speed and the feed rate on the diameter change of a hole using a boring cutter for the internal boring process of AL6061-T4 alloys. The experimental results are quantitatively analyzed by applying the factor analysis and the response surface analysis of the experimental design method. The tendency of the diameter change according to the change in the spindle speed and feed level is also evaluated. During the internal boring process of AL6061-T4 alloys, the main factor affecting the diameter change is the spindle speed in which the diameter decreases as the number of revolutions increases. In addition, the diameter tends to increase as the feed is increased; however, as the number of spindle revolutions increases, the influence of the feed decreases.