Process Parameters Optimization of Laser Cladding for HT200 with 316L Coating Based on Response Surface Method

In order to improve the sealing surface performance of gray cast iron gas gate valves and achieve precise molding control of the cladding layer,as well as to reveal the influence of laser cladding process parameters on the morphology and structure of the cladding layer,we prepared the 316L coating on HT 200 by using Design-Expert software central composite design(CCD)based on response surface analysis.We built a regression prediction model and analyzed the ANOVA with the inspection results.With a target cladding layer width of 3.5 mm and height of 1.3 mm,the process parameters were optimized to obtain the best combination of process parameters.The microstructure,phases,and hardness variations of the cladding layer from experiments with optimal parameters were analyzed by the metallographic microscope,confocal microscope,and microhardness instrument.The experimental results indicate that laser power has a significant impact on the cladding layer width,followed by powder feed rate;scan speed has a significant impact on the cladding layer height,followed by powder feed rate.The HT200 substrate and 316L can metallurgically bond well,and the cladding layer structure consists of dendritic crystals,columnar crystals,and equiaxed crystals in sequence.The optimal process parameter combination satisfying the morphology requirements is laser power(A)of 1993 W,scan speed(B)of 8.949 mm/s,powder feed rate(C)of 1.408 r/min,with a maximum hardness of 1564.3 HV0.5,significantly higher than the hardness of the HT200 substrate.

Optimization of process parameters of aluminum alloy AA 2014-T6 friction stir welds by response surface methodology

The heat treatable aluminum-copper alloy AA2014 finds wide application in the aerospace and defence industry due to its high strength-toweight ratio and good ductility. Friction stir welding(FSW) process, an emerging solid state joining process, is suitable for joining this alloy compared to fusion welding processes. This work presents the formulation of a mathematical model with process parameters and tool geometry to predict the responses of friction stir welds of AA 2014-T6 aluminum alloy, viz yield strength, tensile strength and ductility. The most influential process parameters considered are spindle speed, welding speed, tilt angle and tool pin profile. A four-factor, five-level central composite design was used and a response surface methodology(RSM) was employed to develop the regression models to predict the responses.The mechanical properties, such as yield strength(YS), ultimate tensile strength(UTS) and percentage elongation(%El), are considered as responses. Method of analysis of variance was used to determine the important process parameters that affect the responses. Validation trials were carried out to validate these results. These results indicate that the friction stir welds of AA 2014-T6 aluminum alloy welded with hexagonal tool pin profile have the highest tensile strength and elongation, whereas the joints fabricated with conical tool pin profile have the lowest tensile strength and elongation.

Identification of processing window for extrusion of large thick-walled Inconel 625 alloy pipes using response surface methodology

Identifying suitable processing window is necessary but difficult for achieving favorable microstructure and performance in extrusion of large thick-walled pipe with difficult-to-deform Inconel 625 alloy. In this work, a method was established for identifying the extrusion process window considering temperature control using response surface methodology. Firstly, the response surface models, which correlate temperature rise and peak temperature to key extrusion parameters, have been developed by orthogonal regression based on finite element calculated data. Secondly, the coupled effects of the key extrusion parameters on the temperature rise and peak temperature have been disclosed based on the regression models. Lastly, suitable extrusion processing windows, which are described by contour map of peak temperature in the space of extrusion speed and initial billet temperature, have been established for different extrusion ratios. Using the identified process window, a suitable combination of the key extrusion parameters can be determined conveniently and quickly.

Optimization of Fermentation Process for Human-like Collagen Production of Recombinant Escherichia coli Using Response Surface Methodology

In order to improve the production of human-like collagen III(HLC III)by fed-batch culture of recombinant Escherichia coli BL21,the Plackett-Burman and Box-Behnken design were applied to optimize the fermentation process parameters.Three variables(induction time,inoculum age and pH),which have significant effects on HLC III production,were selected from eight variables by Plackett-Burman design.With the regression coefficient analysis in the Box-Behnken design,a relationship between HLC III production and three significant factors was obtained,and the optimum levels of the three variables were as follows:induction time 3.2h,inoculum age 12.6 h and pH 6.7.The 3D response surface plots and 2D contour plots created by the Box-Behnken design showed that the interaction between induction time and pH and that between innoculum age and pH were significant.An average 9.68 g·L1HLC III production was attained in the validation experiment under optimized condition,which was 80%higher than the yield of 5.36 g·L1before optimization.

Optimization of Solid-state Fermentation Conditions of Sophora japonica cv.jinhuai by Response Surface Methodology

[Objectives]To optimize the solid-state fermentation process of Flos Sophorae Immaturus by Penicillium with Sophora japonica cv.jinhuai as raw material.[Methods]The fermentation conditions were optimized by single factor experiment and response surface methodology with quercetin content as the dependent variable.[Results]According to the established model,the optimal fermentation process of Flos Sophorae Immaturus was obtained as follows:temperature 29.97℃,time 6.88 d,rotation speed 180.86 rpm,inoculation amount 3.93 mL,and the expected content of quercetin was 34.8053 mg/g.Based on this,the fermentation parameters were adjusted,and the actual content was 33.67 mg/g,which was close to the predicted value.[Conclusions]The optimization of fermentation process of Flos Sophorae Immaturus by response surface methodology provides a reference for the development and utilization of this medicinal material.

Multiple-response optimization for melting process of aluminum melting furnace based on response surface methodology with desirability function

To reduce the fuel consumption and emissions and also enhance the molten aluminum quality, a mathematical model with user-developed melting model and burning capacity model, were established according to the features of melting process of regenerative aluminum melting furnaces. Based on validating results by heat balance test for an aluminum melting furnace, CFD （computational fluid dynamics） technique, in association with statistical experimental design were used to optimize the melting process of the aluminum melting furnace. Four important factors influencing the melting time, such as horizontal angle between burners, height-to-radius ratio, natural gas mass flow and air preheated temperature, were identified by PLACKETT-BURMAN design. A steepest descent method was undertaken to determine the optimal regions of these factors. Response surface methodology with BOX-BEHNKEN design was adopted to further investigate the mutual interactions between these variables on RSD （relative standard deviation） of aluminum temperature, RSD of furnace temperature and melting time. Multiple-response optimization by desirability function approach was used to determine the optimum melting process parameters. The results indicate that the interaction between the height-to-radius ratio and horizontal angle between burners affects the response variables significantly. The predicted results show that the minimum RSD of aluminum temperature （12.13%）, RSD of furnace temperature （18.50%） and melting time （3.9 h） could be obtained under the optimum conditions of horizontal angle between burners as 64°, height-to-radius ratio as 0.3, natural gas mass flow as 599 m3/h, and air preheated temperature as 639 ℃. These predicted values were further verified by validation experiments. The excellent correlation between the predicted and experimental values confirms the validity and practicability of this statistical optimum strategy.

Enhacement of the Viability of <i>Lactobacillus</i><i>plantarum</i>during the Preservation and Storage Process Based on the Response Surface Methodology

Objective: The Response Surface Methodology (RSM) is a commonly used system to optimize cell viability of probiotic strains when they are subjected to different preservation and storage processes. Methods and Results: To determine the optimal levels of incorporation of several cry oprotectants (skim milk, sucrose and trehalose) in the freeze-drying process of Lactobacillus plantarum, a range of experiments based on a Rotational Central Composite design (CCD) were conducted. The results were adjusted to a quadratic model, resulting in the presence of interaction between the different variables. Solving a regression equation, we obtained the optimum concentrations of cryoprotective agents: 24.06% milk powder, 6.22% sucrose, 5.63% trehalose. To visualize the interactions between the three variables involved in the study, Design Expert? software was used. Conclusions: The analysis reveals that while trehalose has a direct effect on the viability of L. plantarum, skim milk and sucrose exert quadratic effects. There are also interactions between cryoprotectants, which emphasize the synergies produced between milk and sucrose and between sucrose and trehalose, which allows maintaining the viability of L. plantarum. Significance and Impact of the Study: The addition of new oligosaccharides as trehalose in premixtures for functional feed can maintain the viability of L. plantarum during longer periods of time, ensuring the proper administration of probiotics to their destinations.

Investigation of the processing technology and mechanism of Kansui radix by licorice based on response surface methodology and integrative pharmacology

Background:The herbs should be processed by different methods before use,and the efficacy and toxicity of Chinese herbal medicines may change,which may enhance efficacy and reduce toxicity after processing.Gansui(Kansui radix)is a common clinical herbal medicine,and there are considerable changes in its toxicity and efficacy after processing.Gaocao(Glycyrrhizae radix et rhizome)has a detoxifying effect.Methods:Using the contents of euphorbiadienol and the alcohol-soluble extract of Glycyrrhizae radix-processed Kansui radix as evaluation indexes,response surface methodology was used to optimize the processing technology of Kansui radix by exploring the effects of Glycyrrhizae radix et rhizoma-addition amount,frying temperature,and frying time on the processing technology of Kansui radix.Meanwhile,response surface software was used to analyze experimental data to determine the processing parameters of Kansui radix by Glycyrrhizae radix et rhizoma.Integrative Pharmacology-based Research Platform of Traditional Chinese Medicine is used to analysis the potential ingredients of Kansui radix and verify the potential ingredients by western blotting.Results:The technology of Glycyrrhizae radix et rhizoma-processed Kansui radix was optimized for the Glycyrrhizae radix et rhizoma-addition amount of 27%,frying temperature of 180℃,and frying time of 11 min.The network pharmacology analysis revealed that Kansui radix could cause kidney,liver,and heart injury by the PI3K/AKT signaling pathway.Kansui radix at high or low dose could decrease the ratio of p-AKT/AKT while Glycyrrhizae radix et rhizoma-processed Kansui could increase it.Conclusion:The model established by response surface methodology is relatively accurate and can predict the contents of euphorbiadienol and alcohol extract of processed Kansui radix.The toxic effects and its mechanism of action of Kansui radix and processed Kansui radix on kidney,liver,and heart,from the perspective of systems biology,have provided scientific evidence to its clinical application.

Optimization of plasma-processed air(PPA)inactivation of Escherichia coli in button mushrooms for extending the shelf life by response surface methodology

The effect of plasma-processed air(PPA)treatment with different conditions(time,power andflow rate)on the inactivation of Escherichia coli(E.coli)in button mushroom was evaluated.Response surface methodology(RSM)was applied to optimize PPA treatments on the E.coli of button mushrooms.According to the response surface analysis,the optimal treatment parameters were a treatment time of 12 min,treatment power of 90 W and flow rate of 1.2 l min-1.As with verifying tests from the optimization exercise,the number of E.coli reduced by 5.27 log CFU/g at the determined optimum conditions.The scanning electronic microscopy(SEM)micrography showed that the surface of the E.coli was significantly changed under the optimized PPA treatment.Quality parameters of button mushrooms treated at the determined optimum conditions were compared with untreated samples during the storage for 12 d at 4°C?±?1°C.The PPA treatment was found to be effective in inhibiting microbes and preserving postharvest quality in button mushrooms,and these results suggested PPA treatment may provide an alternative for the sterilization of foodborne and maintaining postharvest of fruits and vegetables.

Optimization of the Ultrasonic-assisted Extraction Process for Total Flavonoids in Primula sikkimensis Hook.by Response Surface Methodology

[Objectives]To optimize the ultrasonic-assisted extraction process for total flavonoids in Primula sikkimensis Hook.[Methods]The effects of ethanol volume fraction,extraction time,extraction temperature,ultrasonic time and solid-to-liquid ratio on the yield of total flavonoids were investigated by single factor method,and the extraction process for total flavonoids in P.sikkimensis was optimized by Box-Behnken experimental design.[Results]The optimal extraction process for total flavonoids in P.sikkimensis was ethanol volume fraction 45%,extraction time 29 min,extraction temperature 80℃,solid-to-liquid 1∶40(g/mL)and ultrasonic time 10 min.Under such conditions,the average yield of total flavonoids in P.sikkimensis was 3.09%.[Conclusions]The optimized extraction process is simple and feasible,and is expected to provide a reference for the extraction of total flavonoids in P.sikkimensis.

Development of six sigma concurrent parameter and tolerance design method based on response surface methodology

Using Response Surface Methodology (RSM), an optimizing model of concurrent parameter and tolerance design is proposed where response mean equals its target in the target being best. The optimizing function of the model is the sum of quality loss and tolerance cost subjecting to the variance confidence region of which six sigma capability can be assured. An example is illustrated in order to compare the differences between the developed model and the parameter design with minimum variance. The results show that the proposed method not only achieves robustness, but also greatly reduces cost. The objectives of high quality and low cost of product and process can be achieved simultaneously by the application of six sigma concurrent parameter and tolerance design.

Optimization of process conditions for drying of catfish(Clarias gariepinus)using Response Surface Methodology(RSM)

Drying is applied to lower the moisture content of fish to a level that can prevent the growth of mould and infestation of micro-organism and thus minimizes microbial degradation.The goal of this work was to optimize the process conditions during electrical oven drying of catfish.Moisture content(MC)was quantitatively investigated during the drying process of catfish sizes using response surface methodology(RSM)to obtain minimum moisture content.The independent process variables for the drying process were temperature(50–70◦C),product thickness(10–20 mm),salt concentration(0–20%)and drying time(480–600 min.).Two factorial interaction(2FI)regression model describing the effects of independent drying process variables on the moisture content was developed.The effects of temperature and drying time were more pronounced for MC than the thickness and salt concentration.The optimum conditions were found to be temperature=63.43◦C,product thickness=14.81 mm,salt concentration=9.07%and drying time=600 min.At these optimum conditions,moisture content was found to be 2.64%w.b.Validation of experimental results with the empirical model was evaluated using coefficient of correlation(R2)which was found for the model equation as,R2=0.994.

Optimization of Inactivation Conditions of High Hydrostatic Pressure Using Response Surface Methodology

Response surface methodology (RSM) was employed in the present work and a second orderquadratic equation for high hydrostatic pressure (HHP) inactivation was built. Theadequacy of the model equation for predicting the optimum response values was verifiedeffectively by the validation data. Effects of temperature, pressure, and pressureholding time on HHP inactivation of Escherichia coli ATCC 8739 were explored. Byanalyzing the response surface plots and their corresponding contour plots as well assolving the quadratic equation, the optimum process parameters for inactivation E. coliof six log cycles were obtained as: temperature 32.2℃, pressure 346.4 MPa, and pressureholding time 12.6min.

Optimization of process parameters for preparation of powdered activated coke to achieve maximum SO_(2)adsorption using response surface methodology

Powdered activated coke(PAC)is a good adsorbent of SO_(2),but its adsorption capacity is affected by many factors in the preparation process.To prepare the PAC with a high SO_(2)adsorption capacity using JJ-coal under flue gas atmosphere,six parameters(oxygen-coal equivalent ratio,reaction temperature,reaction time,O_(2)concentration,CO_(2)concentration,and H_(2)O concentration)were screened and optimized using the response surface methodology(RSM).The results of factor screening experiment show that reaction temperature,O_(2)concentration,and H_(2)O(g)concentration are the significant factors.Then,a quadratic polynomial regression model between the significant factors and SO_(2)adsorption capacity was established using the central composite design(CCD).The model optimization results indicate that when reaction temperature is 904.74℃,O_(2)concentration is 4.67%,H_(2)O concentration is 27.98%,the PAC(PAC-OP)prepared had a higher SO_(2)adsorption capacity of 68.15 mg/g while its SO_(2)adsorption capacity from a validation experiment is 68.82 mg/g,and the error with the optimal value is 0.98%.Compared to two typical commercial activated cokes(ACs),PAC-OP has relatively more developed pore structures,and its SBET and Vtot are 349 m^(2)/g and 0.1475 cm3/g,significantly higher than the 186 m^(2)/g and 0.1041 cm3/g of AC1,and the 132 m^(2)/g and 0.0768 cm3/g of AC2.Besides,it also has abundant oxygen-containing functional groups,its surface O content being 12.09%,higher than the 10.42%of AC1 and 10.49%of AC2.Inevitably,the SO_(2)adsorption capacity of PAC-OP is also significantly higher than that of both AC1 and AC2,which is 68.82 mg/g versus 32.53 mg/g and 24.79 mg/g,respectively.

Optimization of Ultrasonic-enzymatic Extraction of Total Flavonoids from Cardamine tangutorum O.E.Schulz by Response Surface Methodology and Content Determination

[Objectives]This study aimed to optimize the extraction process of total flavonoids in Cardamine tangutorum O.E.Schulz.[Methods]On the basis of single-factor experiments,the ultrasonic-enzymatic extraction process of total flavonoids in C.tangutorum O.E.Schulz was optimized by Box-Behnken design from aspects of ethanol volume fraction,extraction time,extraction temperature and enzyme addition,with yield of total flavonoids as the evaluation index.[Results]The optimal extraction process of total flavonoids in C.tangutorum O.E.Schulz was as follows:ethanol volume fraction of 70%,ultrasonic extraction time of 43 min,ultrasonic extraction temperature of 37℃and cellulose addition of 0.07 mg.Under the optimal conditions,the yield of total flavonoids from C.tangutorum O.E.Schulz reached 75.90 mg/g.[Conclusions]The optimized extraction process was reasonable and feasible,and it could provide a reference for the extraction of total flavonoids in C.tangutorum O.E.Schulz.This study provided a foundation for the quality control of food/medicinal materials and the development and research of big health products of C.tangutorum O.E.Schulz.

Optimization of the Degradation of Hydroquinone, Resorcinol and Catechol Using Response Surface Methodology

A clay catalyst (montmorillonite and kaolinite) was prepared and used to degrade three phenolic compounds: hydroquinone, resorcinol and catechol obtained from the treatment the Olive Mill Wastewater (OMW) generated in the production of olive oil. The operating conditions of the degradation of these compounds are optimized by the response surface methodology (RSM) which is an experimental design used in process optimization studies. The results obtained by the catalytic tests and analyses performed by different techniques showed that the modified montmorillonites have very interesting catalytic, structural and textural properties;they are more effective for the catalytic phenolic compound degradation, they present the highest specific surface and they may support iron ions. We also determined the optimal degradation conditions by tracing the response surfaces of each compound;for example, for the catechol, the optimal conditions of degradation at pH 4 are obtained after 120 min at a concentration of H2O2 equal to 0.3 M. Of the three phenolic compounds, the kinetic degradation study revealed that the hydroquinone is the most degraded compound in the least amount of time. Finally, the rate of the catalyst iron ions release in the reaction is lower when the Fe-modified montmorillonites are used.

Overview on Application of Response Surface Methodology （RSM） in Treatment of Palm Oil Mill Effluent （POME）

There are many factors affecting the performance of a treatment system especially in the treatment of palm oil mill effluent （POME） as its contains high amounts of suspended solid, low pH, high salt content and high chemical oxygen demand （COD）. However, one factor at a time approach is complicated method in establishing relationship between multiple parameters. Response surface methodology （RSM） is a recommended approach as it is widely used to analyze and study the interactions between multiple parameters and provides optimum output as well as minimizing the defects which result in good treatment system. This paper overviews the recent and current research in the application of RSM in optimizing the treatment development of POME.

Optimization of the processing technology of Fructus Arctii by response surface methodology

The present study was designed to optimize the processing of Fructus Arctii by response surface methodology （RSM）. Based on single factor studies, a three-variable, three-level Box-Behnken design （BBD） was used to monitor the effects of independent variables, including processing temperature and time, on the dependent variables. Response surfaces and contour plots of the contents of total lignans, chlorogenic acid, arctiin, and aretigenin were obtained through ultraviolet and visible （UV-Vis） monitoring and high performance liquid chromatography （HPLC）. Fructus Arctii should be processed under heating in a pot at 311℃, medicine at 119℃ for 123s with flipping frequently. The experimental values under the optimized processing technology were consistent with the predicted values. In conclusion, RSM is an effective method to optimize the processing of traditional Chinese medicine （TCM）.

Optimization of Extraction Process of Clerodendrum philippinum Schauer var. simplex Mlodenke Total Flavonoids(CPTF) by Central Composite Design-Response Surface Methodology

[Objectives] The research aimed to optimize extraction process of Clerodendrum philippinum Schauer var. simplex Mlodenke total flavonoids( CPTF),and provide reference for its development and utilization. [Methods] Based on single-factor test,ethanol concentration,extraction temperature and extraction time were taken as independent variables,and total flavonoids yield was taken as dependent variable. The test was conducted according to central composite design principle. Multivariate linear regression and binomial equation fitting of the result were conducted,and extraction process of CPTF was optimized by using response surface methodology. [Results]The optimal extraction process of CPTF was as below: ethanol concentration 54. 76%,extraction temperature 83. 92℃,extraction time 102. 64 min,solid-liquid ratio 1:20,extraction for twice. [Conclusions] The extraction process of CPTF by central composite design-response surface methodology was simple and feasible,with reliable prediction result,which was suitable for industrial production.

Optimization of Extraction Process of Total Flavonoids from Akebia trifoliata (Thunb.) Koidz. by Central Composite Design-Response Surface Methodology

[Objectives]To optimize extraction process of total flavonoids from Akebia trifoliata( Thunb.) Koidz.,so as to provide references for development and use of Akebia trifoliata( Thunb.) Koidz. [Methods]The extraction rate of total flavonoids of Akebia trifoliata( Thunb.)Koidz. was taken as observation indicator. On the basis of single factor experiment,central composite design( CCD) was used to evaluate the effects of the extraction temperature,extraction time,and ethanol concentration on the extraction process. Multiple linear regression and binomial fitting were used,and response surface methodology( RSM) was used to select the optimum extraction process. [Results] The optimum extraction process conditions for total flavonoids of Akebia trifoliata( Thunb.) Koidz. was extraction temperature: 83. 92 ℃; extraction time:96. 47 min; ethanol concentration: 63. 92%; extraction times: two times; solid to liquid ratio: 1 ∶ 20; extraction rate of total flavonoids:4. 55%. [Conclusions] The central composite design-response surface methodology( CCD-RSM) is simple,convenient,and feasible for extraction of total flavonoids from Akebia trifoliata( Thunb.) Koidz.,and the prediction results are reliable.