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.

Compression Responses of Preform in Vacuum Infusion Process

The final thickness of a product after the vacuum infusion process （VIP）, which is equal to the fiber volume fraction, depends in part on the compression responses of the preform because one of the mold faces is flexible in VIE This study aims at investigating the compression responses of different fabrics under dry or wet conditions. The main factors affecting the compression response under investigation include, the vacuum pressure, the loading and unloading repeatability on the preform, the layup design, the kinds of fabrics, and the resin viscosity. Besides, the effects of some internal factors such as nesting and elastic recovery of fibers, lubrication of resin, friction between fibers, and so on, are also studied. In the end, this article expatiates the meaning of the matching requirements of the permeability of the preform and that of the distribution medium.

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.

Predictive functional control of integrating process based on impulse response

The predictive model is built according to the characteristics of the impulse response of integrating process. In order to eliminate the permanent offset between the setpoint and the process output in the presence of the load disturbance, a novel error compensation method is proposed. Then predictive functional control of integrating process is designed. The method given generates a simple control structure, which can significandy reduce online computation. Furthermore, the tuning of the controller is fairly straightforward. Simulation results indicate that the designed control system is relatively robust to the parameters variation of the process.

Board-invited review: Sensitivity and responses of functional groups to feed processing methods on a molecular basis

In complex feed structures, there exist main chemical functional groups which are associated with nutrient utilization and availability and functionality. Each functional group has unique molecular structure therefore produce unique molecular vibration spectral profile. Feed processing has been used to improve nutrient utilization for many years. However, to date, there was little study on processing-induced changes of feed intrinsic structure and functional groups on a molecular basis within intact tissue. This is because limited research technique is available to study inherent structure on a molecular basis. Recently bioanalytical techniques： such as Synchrotron Infrared Microspectroscopy as well as Diffuse Reflectance Infrared Fourier Transform molecular spectroscopy have been developed. These techniques enable to detect molecular structure change within intact tissues. These techniques can prevent destruction or alteration of the intrinsic protein structures during processing for analysis. However, these techniques have not been used in animal feed and nutrition research. The objective of this review was show that with the advanced technique, sensitivity and responses of functional groups to feed processing on a molecular basis could be detected in my research team. These functional groups are highly associated with nutrient utilization in animals.

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.

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.

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 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.

APPROACH TO KARST SOLUTION PROCESS RESPONSES ON CLIMATE

Based upon the studies of solutional rates with environment from South China to North China over a range of about 30 。 latitude, this paper discusses some of the consequence with equations. The response model shows that the precipitation is the most important factor influencing the rate of solutional denudation except the lithology, the relief etc., but it is an integrational action on the solution process; at the same time, temperature acts as a threshold in bringing the precipitation into play. These suggest that firstly, the solutional denudation process is a comprehensive response to the multiple factors; secondly, karst solution is a complex response process to the climate, and as an integrated exogenic process under the bioclimate.

ROBUST SMITH PREDICTIVE CONTROLLER FOR PROCESS WITH INVERSE RESPONSE

Smith predictor known as the time delay compensator was extended to control the process with inverse response.Modern robust control theory was employed to design the robust controller,which has only one parameter to be determined with compromise among the rise time,undershoot,robustness and capability to reject disturbance of the closed loop system.The former two specifications can be assessed quantitatively and the latter two qualitatively.Examples show that the proposed method has significant improvements and wide applicable ranges for inverse response process.

ON THE RESPONSE FUNCTIONALS OF MATERIALS FOR THE IRREVERSIBLE PROCESSES OF THERMODYNAMICS

Based on the continuum physics and taking into account variation of the heat dissipation, Helmholtz free ener-gy, internal energy and exothermicity with the thermodynamic process, in this paper, the functional equations of the general-ized stress and entropy associated ivith the time and temperature are derived for the irreversible process of thermoviscoelastic-plastic materials. As an example, the response functionals of Maxwell viscoelastic materials are obtained.

Response Process of Oceanto AtmosphericForcing and Optimal Response Frequency in the CZ Ocean Model

Ocean response to atmospheric forcing in the CZ ocean model is analyzed.The results show that Nino 3 indexfrom the CZ ocean model driven by linear composite of biennial,ENSO and even annual time scale wind stressanomalies is consistent well with composite of responding two or three components of observed Nino 3 index duringthe EI Nino period while the La Nina phenomena cannot be reproduced by the linear composite.It implies that linearresponse process for ocean response to atmospheric forcing is dominated during the EI Nino period while nonlinearresponse might be main process during the La Nina period.Simulated results also suggest that optimal response frequency of the CZ ocean model is the frequency lowerthan annual variability and ocean response to the atmospheric forcing with annual time scale can give rise to incorrectsignal-errors in the simulated SSTA field.

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.

Cellular processing determinants for the activation of damage signals in response to topoisomerase I-linked DNA breakage

Recent studies have suggested an involvement of processing pathways for the initiation of cellular responses induced by topoisomerase-targeting drugs. Here, we showed that cellular exposure to camptothecin （CPT） induced formation of topoisomerase I cleavable complex （TOPlcc）, degradation of TOP1 and activation of DNA damage responses （DDR）. Transcription and proteasome-dependent proteolysis, but not replication, were involved in CPTo indneed TOPl degradation, while none of above three processing activities affected TOPlcc formation. Replication- and transcription-initiated proeessing （RIP and TIP） of TOPlee were identified as two independent pathways, which contribute distinctly to various CPT-activated DDR. Specifically, in cycling cells, RIP-processed TOPlec triggered the CPT-induced RPA pbosphorylation. At higher CPT dosages, the TIP pathway is required for other DDR activation, including ATM, p53 and Chkl/2 phosphorylation. The TIP pathway was further demonstrated to be S-phase independent by using three nonreplicating cell models. Furthermore, the effect of proteasome inhibitors mimicked that of transcription inhibition on the CPT-induced activation of DDR, suggesting the involvement of proteasome in the TIP pathway. Interestingly, the TIP pathway was important for TOPlcc-activated, but not ionization radiationactivated ATM, p53 and Chk2 phosphorylation. We have also found that pharmacological interferences of TIP and RIP pathways distinctively modulated the CPT-induced cell killing with treatments at low and high dosages, respec- tively. Together, our results support that both RIP and TIP pathways of TOPlcc are required for the activation of CPT-induced DDR and cytotoxicity.

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.

Spatial and temporal variation process of seabed dynamic response induced by the internal solitary wave

Internal solitary wave(ISW)is often accompanied by huge energy transport,which will change the pore water pressure in the seabed.Based on the two-dimensional Biot consolidation theory,the excess pore water pressure in seabed was simulated,and the spatiotemporal distribution characteristics of excess pore water pressure was studied.As the parameters of both ISW and seabed can affect the excess pore water pressure,the distribution of pore water pressure showed both dissipation and phase lag.And parametric studies were done on these two phenomena.Due to influenced by the phase lag of excess pore water pressure,the penetration depth under the site of northern South China Sea with total water depth 327 m,induced by typical internal solitary wave increased by 26.19%,53.27%and 149.86%from T_(0)to T_(0.5)in sand silt,clayey silt and fine sand seabed,respectively.That means the effect of ISW on seabed will be underestimated if we only take into accout the penetration depth under ISW trough,especially for fine sand seabed.In addition,the concept of“amplitude-depth ratio”had been introduced to describe the influence of ISW on seabed dynamic response in the actual marine environment.In present study,it is negatively correlated with the excess pore water pressure,and an ISW with smaller amplitude-depth ratio can wide the range of lateral impacts.Our study results help understand the seabed damage induced by the interaction between ISW and seabed.

Optimization of the extraction process of total flavonoids from Trichosanthis Fructus by Box-Behnken response surface method combined with differential spectrophotometry

Objective:To optimize the extraction process of total flavones in Trichosanthis Fructus(composed of Trichosanthis pericarpium and Trichosanthis semen in certain proportion).Methods:The effects of the mixture ratio of Trichosanthis pericarpium and Trichosanthis semen,ethanol concentration,ultrasonic extraction time and extraction temperature on the extraction rate of total flavonoids in Trichosanthis Fructus were investigated.The extraction process of total flavonoids in Trichosanthis Fructus was optimized by Box-Behnken response surface method combined with differential spectrophotometry.Results:The optimum extraction conditions of total flavonoids in Trichosanthis Fructus were as follows:The mixture ratio of Trichosanthis pericarpium and Trichosanthis semen was 4:6,the ethanol concentration was 70%,the ultrasonic extraction time was 60min and the extraction temperature was 40℃.Conclusion:Box-Behnken response surface method combined with differential spectrophotometry can optimize the extraction process of total flavonoids from Trichosanthis Fructus,which can provide reference for the extraction and application of total flavonoids in Trichosanthis Fructus.