جستجوی مقالات مرتبط با کلیدواژه « Response surface methodology » در نشریات گروه « مواد و متالورژی »

The present research has studied the effect of adding perlite and natural rubber nanoparticles with various weight percentages on the tensile modulus and impact strength of polypropylene. For this purpose, different samples were produced and tested using an internal mixer based on the standards of tensile and impact tests. Also, by using of response surface methodology (RSM), the role of input parameters on the responses was investigated in order to achieve optimal mechanical properties and predict these properties with mathematical models in the form of central composite five-level design (CCD). In addition, the SEM test was used to observe the changes made in the microstructure of the samples. The results showed that the addition of 7 wt.% of pearlite nanoparticles to the matrix containing 20 wt.% of natural rubber, the value of the tensile modulus increased by 11.27% and the impact strength by 52.01% compared to the addition of 3 wt.% of pearlite nanoparticles to the same matrix. The results of multiobjective optimization proved that the optimal weight percentage of pearlite nanoparticles and natural rubber was 4.04 and 35.26% wt. respectively. Is. In this case, the highest value obtained for tensile modulus was 508.04 MPa and impact strength was determined to be 108.52 J/m. By observing the SEM images, it was concluded that the change in the size of the elastomeric phase due to the use of different weight percentages of reinforcements has caused the results of the mechanical properties of the samples to differ from each other.

Chromate conversion coatings with anti-corrosion properties are used as coatings for external elements of space systems. The three main properties of these coatings that are effective in aerospace application are: corrosion resistance, adhesion strength of the coating to the substrate and abrasion resistance. In this paper, the parameters affecting these properties were investigated and in order to optimize these parameters, the response surface methodology (RSM) method was used in MiniTab program. Variable parameters are temperature, amount of refiner and amount of accelerator. The amount of constituent material, reaction time and age time were considered constant for all samples. The corrosion resistance, adhesion strength of the coating to the substrate and abrasion resistance are determined by salt spray test in 0.5% saline medium for 336 hours, Pull Off test and pin on disk wear test, respectively. The maximum amount of corrosion resistance obtained for chromate coating which was 71.8% of the surface remind intact, with the combination of 4 g/lit refiner, 1.8 g/lit accelerator at 45 °C. The maximum amount of coating stress from the substrate surface was 1.2 MPa, which was obtained in the amount of 4 g/lit refiner, 1.8 g/lit accelerator and 35 °C temperature. The minimum weight loss due to abrasion was 0.2 mg, which was obtained for coating with the composition 4 g/lit refiner, 6 g/lit accelerator at 35 °C. Therefore, by increasing the amount of accelerator and temperature, the thickness of the coating increased, and this increase to the optimum level increases the abrasion resistance and adhesion strength of the coating, but when the thickness increases beyond the optimum, the abrasion resistance and adhesion strength decrease.

Zeolite were formed through agar gelcasting method.Response surface methodology ( RSM ) is proposed as a  tool for rapidly optimizing the activation parameters in order to obtain the highest porosity of samples. 40 % of zeolite and 1 wt %  of agar was selected as optimal conditions. porous bodies with an optimal combination of 54.4% porosity , density 0.9 g / cm3 , and  compressive strength of 6.67MPa  were made  and  observed that there is a slight difference between predicted  values by the software and the measured values.  Longer time to mixing from 1 / 5 min to 3 min , the porous body has 67.17 % porosity , density 0.69 g / cm3 , and compressive strength of 5 / 3 MPa .XRD and SEM analysis was used  to investigate the  phase and structural changes at 800 C. The highest percentage of adsorption of methylene blue at 4ppm concentration after 72 h was 98.94 %.

In this paper, the addition of silicon carbide (SiC) nanoparticles to polyamide 6 (PA6) / acrylonitrile-butadiene rubber (NBR) blends was performed by friction stir process. In order to achieve optimal mechanical responses of tensile strength and elongation at break, response surface methodology (RSM) was used to optimize the process parameters of rotational speed (ω), traverse speed (V) and material parameter as silicon carbide nanoparticles (S) content. The validation of the mechanical results was done with compare the microstructure of nanocomposite samples by scanning electron microscopy (SEM). Using mathematical models, the results showed that tensile strength and elongation at break are increased by increasing the rotational speed from 800 rpm to 1200 rpm when the values of silicon carbide content and traverse speed are constant. By selecting the rotational speed of 1200 rpm, traversed speed of 20 mm/min, and 2.784 wt.% of SiC process and material parameters, the maximum tensile strength, and elongation at break can be achieved. Observation of scanning electron microscopy images confirmed that the changes in mechanical properties are related to the changes in the elastomeric phase of NBR.

In the present study, the electrochemical coagulation process (electrocoagulation) in the mining industry to remove arsenic ions from the charged leaching solution of PLS (copper processing plant) has been investigated. Samples were obtained by simulating the leaching process by adding trivalent arsenic salt (NaAsO2). The effects of three independent parameters such as pH (X1), electrolysis time (X2), current density (X3) were investigated using the response surface methodology (RSM) to investigate the removal of arsenic from PLS solution. This design includes 17 sets of experiments using electrocoagulation system. In this study, the Box-Benken test design in the response surface method with three numerical factors at three levels was investigated to investigate the interactive effect of process variables to evaluate the efficiency of arsenic removal from leaching solution using electrocoagulation method. The optimal conditions for the electrocoagulation process were determined at pH 6.50, electrolysis time: 114 minutes and electric current density of 65.3 A/m2, with a removal efficiency of 96.88%. The results showed that the ability of electrocoagulation process as a reliable method to remove metal ions, especially arsenic ions from the effluents of the mining industry, especially in mineral processing plants is very desirable.

In this paper, nanocomposites based on polyamide 6 (PA6)/acrylonitrile-butadiene rubber (NBR)/Perlite were prepared by melt mixing technique in an internal mixer. Response surface methodology (RSM) and central composite design (CCD) were used to study the influence of two material variables including perlite content and NBR content on tensile strength and impact strength of PA6/NBR/Perlite nanocomposites. The microstructure of nanocomposites samples was also examined to confirm the result obtained by scanning electron microscopy images. Based on the results obtained from the response surface methodology, when NBR phase content is 20%wt., with increasing perlite nanoparticles from 3% to 7% wt., the value of tensile strength increased by 12.9% and on the other hand, the value of impact strength decreased by 47.7%. Under optimal conditions of perlite content of 4.37 wt. and NBR content of 34.83 wt., the simultaneous maximization of the tensile strength (58.4 MPa) and impact strength (66.3 J/m) could be obtained. Observations of scanning electron microscopy images showed that the difference in mechanical results was due to the different sizes of the elastomeric phase in different compounds.