جستجوی مقالات مرتبط با کلیدواژه "response surface method" در نشریات گروه "برق"

In this study, for the first time, the thermal behavior of TiO2 (85%) / MWCNT (15%) - (CH2OH) 2 (50%) / H2O (50%) hybrid nanofluid thermal behavior is investigated. The thermal conductivity of the nanofluid is determined by KD2 PRO at fractional volumes of  φ =0.03% -0.6% and temperatures of T = 28 ° C-50 ° C. Nanoscale and nanoparticle structure validation are performed using transmission electron microscopy (TEM) and scanning (SEM) and X-ray diffraction (XRD) analysis tools. Experimental results of laboratory analyzes have shown that with increasing temperature and volume fraction, relative thermal conductivity (RTC) is increasing and the amount of this increase is more severe for volume fraction than temperature. The statistical results of experimental analysis showed that the minimum and maximum increase in thermal conductivity of nanofluid compared to the base fluid are 1.6% and 17.9%, respectively. The modeling of the response surface for the relative thermal conductivity of nanofluid showed that the values of R2 and Adj R2 were equal to 0.9882 and 0.9860, respectively, and the MOD value was between -1 and +1.

Multi-response problems are always one of the most challenging areas of optimization. In this paper, the ROYKA hybrid method is presented to optimize multi-response problems, which is a combination of two methods of response surface and data envelopment analysis. In the ROYKA method, the efficiency surface is created and optimized, and in fact, one efficiency surface replaces several response surfaces, and the problem is changed from a multi-response mode to a single response. Therefore, in the proposed method, in addition to optimizing the response surface, the efficiency of decision-making units is also maximized. The result of this method is to determine the input and output parameters of the ideal and new decision-making unit, which also has the maximum amount of efficiency.Due to the high importance of the electricity industry and energy production, power plants, which are responsible for a very important part of electricity generation, have to increase the efficiency of their activities in order to make better use of resources. For this purpose, the proposed method of ROYKA for fourteen power plants in the country has been studied, which in addition to determining the efficiency of each power plant to determine the optimal parameters for the construction of a new power plant with maximum efficiency. Finally, in order to validate the proposed method, three other similar approaches have been used for the mentioned problem and the results show the superiority of the ROYKA method.

Parameters of meta-heuristic algorithms are very effective in their performance and are usually done experimentally, which is very time-consuming. In this research, a hybrid method for selecting the optimal parameters of meta-heuristic algorithms is presented. The proposed method is a combination of data envelopment analysis methods and response surface methodology and is called DSM. In fact, this method can be used to optimize multi-objective problems and its main advantage is to create and optimize one performance response procedure instead of optimizing multiple output response procedures. In addition to optimizing parameters, it also simultaneously maximizes efficiency. In this research, the proposed DSM method has been used to adjust the parameters of the cuckoo optimization algorithm to optimize the standard and experimental Aklay and Rastrigin functions. In the hybrid DSM method, first, the efficiency value is calculated using data envelopment analysis for each set of meta-heuristic algorithm parameters, then the response procedure for performance is determined according to the meta-heuristic algorithm parameters using the response surface methodology. Finally, by optimizing the efficiency surface, the optimal values of the cuckoo algorithm parameters are obtained. In order to validate, the results of the proposed method have been compared with a similar method. The results show better performance of the hybrid algorithm in terms of solution time, number of iterations, and accuracy of the optimization function compared to other similar methods.

In the roll forming process, control of input parameters is essential in order to maintain the quality of the final profile. In this investigation, a new hybrid approach is used for optimization of the roll forming process. That is based on the finite element simulation. Firstly, the process was modeled using the finite element method and then verified with the experimental results. Then necessary experiments have been designed using the central composite design method. In this design roll diameter, distance and number of stands and linear velocity of the sheet are considered as input variables and maximum plastic longitudinal strain and angle precession (reverse of spring back) are considered as response functions. Then the response surface model of the objective functions was obtained using the response surface method based on the finite element outputs of the runs. Finally, optimum point of the input parameters has been obtained using the desirability function approach. Results show that the response surface method can model the effect of the input parameters on the objective functions precisely. According to this model, increasing of distance of the stands and roll diameter, lead to decreasing of maximum plastic longitudinal strain. Increasing the linear velocity of the sheet leads to decreasing the maximum plastic longitudinal strain. Decreasing distance and increasing number of stands cause to increase the angle precession and increasing the linear velocity of the blank leads to decreasing of the angle precession. Also optimization results represent increasing of the angle precession and decreasing of the maximum plastic longitudinal strain in comparison to conventional results.

Friction stir welding is a solid state process which is developed by Twi institute in 1991. In this paper، lap welding of 5456 aluminum alloy sheets were carried out while hard working H321 sheet with a thickness of 5 mm was on top of a 2. 5 mm thickness annealed sheet and the simultaneous effect of rotation speed of tool، feed rate and tool angle parameters on failure force and the height of hook in friction stir welding were investigated using response surface method. After evaluation and analysis of welding samples، response surface method was used using experimental results and several verification models were performed for error estimation. The results of mechanical properties of model show 3. 88 percent average error with experimental results. In proceeding، the analysis of variance was used for investigation of the welding parameters effect on welding mode variations and it was seen that feed rate has the greatest effect on failure force and rotation speed has the greatest effect on the hook height and tool angle has the lowest effect in comparison with this two parameters.