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Performance evaluation and multi-response optimization of grinding-aided electrochemical discharge drilling (G-ECDD) of borosilicate glass
摘要： Machining of advanced glass ceramics is of great importance and is a challenging task for the modern industries. In this study, a new hybrid technique of grinding-aided electrochemical discharge drilling (G-ECDD) is attempted which combines the grinding action of a rotating abrasive tool and thermal melting action of electrochemical discharges to perform drilling of borosilicate glass. G-ECDD is performed using a normal electrochemical discharge machine set-up with a provision for using a rotating diamond-coated drill tool. The tool used is a hollow diamond core drill rather than the traditional solid abrasive tool. A spring-fed tool system was designed and developed to provide the tool-feed movement which will also help to maintain a balance between grinding action of diamond grits and thermal melting action of discharges. Preliminary experiments are conducted to identify the optimum spring force of the spring-fed system and tool rotational speed which can facilitate a balanced ECDM and grinding action for material removal. The effect of machining parameters like voltage, duty ratio, pulse cycle time and electrolyte concentration on material removal rate (MRR) and hole radial overcut (ROC) is investigated using response surface methodology (RSM). Duty ratio and voltage are found to be the most significant factors contributing MRR. Voltage and pulse cycle time are identified as the main factors controlling radial overcut of the drilled holes. Second-order regression models for MRR and ROC are developed using the data collected from the experiments using RSM. Grey relational analysis was used to optimize this multi-objective problem. A voltage of 90 V, duty ratio of 0.7, cycle time of 0.002 s and an electrolyte concentration of 3.5 M are found to be the best combination for optimizing the responses. Deterioration of bonding material and dislodging of diamond grits are found to be the major modes of tool wear during G-ECDD. The use of high-frequency pulsed DC increased the tool wear rate due to the less time available for heat dissipation between discharge cycles. Moreover, the wear at the end face of the tool will be accelerated due to the concentration of current density at edges during high-frequency operation. From the microscopic images of the machined surface, the material removal mechanisms involved in G-ECDD are found to be a combination of thermal melting by discharges, grinding action of diamond grits and high-temperature chemical etching effect of the electrolyte.
关键词： Electrochemical discharge machining,Response surface methodology,Tool wear,Radial overcut,Grey relational analysis,Material removal rate,Material removal mechanism,Grinding
更新于2025-09-11 14:15:04
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Optimization of Operating Parameters in a Planetary CVD Reactor Using Response Surface Methodology
摘要： Film thickness uniformity is an important index to measure the quality of a deposited layer in selective epitaxial growth (SEG) of silicon using the chemical vapor deposition (CVD) process. The uniformity of a thin film is related to many parameters, such as rotation speed of a wafer, total flow rate, species concentration, susceptor temperature, and operating pressure. Therefore, it is very important to address the problem of coupling multiple parameters and solve the optimization in a computationally efficient manner. In this work, response surface methodology (RSM) is used to analyze the complex coupling effects of different operating parameters on silicon deposition uniformity. Based on the computational fluid dynamics (CFD) model, an accurate RSM model is obtained to predict non-uniformity with different parameters, including temperature, pressure, rotation speed of a wafer, and mole fraction of dichlorosilane (DCS). Analysis of variance (ANOVA) is conducted to determine the statistical significance of each factor in an empirical equation for the expected response. The results of ANOVA analysis indicate the goodness of fit of the regression model. The optimum combination of operating parameters of the problem considered in this study is a susceptor temperature of 1122.2 K, wafer rotation speed of 23.72 rpm, operating pressure of 112 Torr, and DCS mole fraction of 0.01186. The validation tests and optimum solution show that the results are in good agreement with those from the CFD model, and the maximum deviation between the computational solution and predicted values is 2.93%.
关键词： Response surface methodology,Chemical vapor deposition,Epitaxial growth,Deposition uniformity
更新于2025-09-10 09:29:36
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Degradation of Paracetamol by an UV/Chlorine Advanced Oxidation Process: Influencing Factors, Factorial Design, and Intermediates Identification
摘要： The combination of a low-pressure mercury lamp and chlorine (UV/chlorine) was applied as an emerging advanced oxidation process (AOP), to examine paracetamol (PRC) degradation under different operational conditions. The results indicated that the UV/chlorine process exhibited a much faster PRC removal than the UV/H2O2 process or chlorination alone because of the great contribution of highly reactive species (?OH, ?Cl, and ClO?). The PRC degradation rate constant (kobs) was accurately determined by pseudo-first-order kinetics. The kobs values were strongly affected by the operational conditions, such as chlorine dosage, solution pH, UV intensity, and coexisting natural organic matter. Response surface methodology was used for the optimization of four independent variables (NaOCl, UV, pH, and DOM). A mathematical model was established to predict and optimize the operational conditions for PRC removal in the UV/chlorine process. The main transformation products (twenty compound structures) were detected by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS).
关键词： paracetamol,response surface methodology,UV/chlorine,transformation products,reaction kinetics
更新于2025-09-09 09:28:46
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Optimization of photocatalytic degradation of dye?wastewater?by CuFe<sub>2</sub>O<sub>4</sub>/AgBr composite using response surface methodology
摘要： In this paper, a simple response surface methodology (RSM) based on central composite design (CCD) was applied to determine the optimum processing parameters of photocatalytic degradation of acid red 88 (AR88) by CuFe2O4/AgBr composites. The effect of CuFe2O4 loading, initial concentration of pollutant, and photocatalyst concentration on the yield of AR88 degradation rate was investigated. Based on the statistical experimental design, the maximum degradation rate of 94.7% was achieved under optimal conditions: the 34.69% of CuFe2O4 loading, 16.34mg/L of intial concentration of AR88, 1.51g/L of photocatalyst concentration. The kinetics exploration indicated that the degradation process fitted pseudo-first order kinetic model. What’t more, the trapping experiment of active species demonstrated that ·O2- and ·OH were the dominant species.
关键词： CuFe2O4/AgBr composites,response surface methodology,central composite design,acid red 88,photocatalysis
更新于2025-09-04 15:30:14
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Optimization and modeling of UV-TiO <sub/>2</sub> mediated photocatalytic degradation of golden yellow dye through response surface methodology
摘要： In this article, heterogeneous photocatalysis of golden yellow (GY) dye by Evonik p25 titanium dioxide (PTD) and UV radiations was optimized by using central composite design of response surface methodology. The GY dye photocatalysis was expressed as the function of amount of PTD loading (X1), GY dye initial concentration (X2), and UV irradiance intensity (X3). The optimization of degradation conditions was done by measuring two different responses, that is, color removal (Y1) and chemical oxygen demand removal (Y2). The effect of X1, X2, and X3 were studied in the range 0.5–1.5 g/L, 15–35 W/m2, and 10–30 mg/L, respectively. The quadratic model was suggested for Y1 and Y2. The numerical optimization of results was done via Design Expert software. The predictive results obtained were verified by performing actual experiments. The photodegradation kinetics, total organic carbon disappearance, effect of inorganic salts, and H2O2 concentration on GY dye photodegradation were also studied.
关键词： Titanium dioxide,Heterogeneous photocatalysis,Central composite design,Optimization,Golden yellow dye,Response surface methodology
更新于2025-09-04 15:30:14