Design Of Response Surface Method Research Articles

Preparation of Cangyi nanoemulsion in situ gel and drug release mechanism of nasal mucosa in vitro

To prepare Cangyi nanoemulsion in situ gel and study its nasal mucosa release mechanism in vitro. After proper treatment of different drugs in the compound, the prescription of nanoemulsion was determined by pseudo-ternary phase diagram method. With the ratio of mixed emulsifier to oil phase [(S+COS)/O], the ratio of mixed emulsifier(K_m), the ratio of water phase to mixed emulsifier and oil phase[W/(S+COS+O)] as investigation factors and the normalized value(OD) as evaluation index, the prescription of Cangyi nanoemulsion was optimized by central composite design-response surface method. With the ratio of poloxamer 407(P407) and poloxamer 188(P188) as the investigation factors and the gelation temperature as the evaluation index, the in situ gel prescription of Cangyi nanoemulsion was optimized. The improved Franz diffusion cell was used to explore the nasal mucosa drug-release mechanism of Cangyi nanoemulsion in situ gel with oxymatrine, ferulic acid and salvianolic acid B content as indexes. The optimal prescription of Cangyi nanoemulsion in situ gel was as follows: 6.862% castor oil polyoxyl(EL), 4.262% absolute ethanol, 1.392% ethyl oleate, 7% P407 and 6% P188. The average pH was 5.55 and the average gelation temperature was 32.8 ℃. In vitro release studies showed that oxymatrine, ferulic acid and salvianolic acid B were released simultaneously and the drug release behavior was consistent with that in Higuchi model. The preparation process of Cangyi nanoemulsion in situ gel is stable, with suitable pH value, gelation temperature and viscosity. It has a certain slow-release effect, and can meet the needs of local nasal drug use.

Automatic solvent extraction of sour cherry peels and storage stability of the products

Conversion of biomass (particularly waste of agricultural and food products) into high-added value compounds has been an attractive research field recently. Therefore, developing an alternative downstream process to recover the relevant biologically active components is of great significance. In this study, waste of sour cherry has been used as a source of phenolic compounds rich in anthocyanins. As an advanced alternative technology, automatic solvent extraction has been used to recover phenolics from sour cherry peels. The process factors (immersion time, washing time, solid mass and solvent concentration) of this novel method were optimized by face-centered composite design of response surface method. Chromatographic analysis (HPLC) was also used to measure the major anthocyanin (cyanidin-3-glucoside) of the samples. The process was optimized in order to maximize the dependent factors such as total phenolic and anthocyanin content extractions measured spectrophotometrically. Maximum predicted TPC and TA yields on optimized conditions were 119.63 mg GAE/g FM and 24.31 mg cyanidin-3-glucoside/g FM, respectively (23.79 min immersion time, 52.21 min washing time, 0.47 g solid mass, 80% solvent concentration). A stability assay under different conditions (light, dark, ambient condition, refrigerator and deep freezer) has been also performed in order to monitor the stability of bioactivity profile (total phenolic and anthocyanin contents and cyanidin-3-glucoside level). All of the independent parameters (immersion time, washing time, solid mass and solvent concentration) were significant at the level of p > 0.05. The solvent concentration was identified to be the most significant parameter on the yields obtained by automatic solvent extraction.

Study on Properties of 45 Carbon Steel Ni-P Electroless Plating Reinforced by Si₃N₄-Al₂O₃ Particle Based on Response Surface Method.

The effects of the different content of Si³N⁴ particles and Al²O³ particles in the plating solution and the different ratios on the wear resistance, microhardness, corrosion resistance and other properties of the coating were analyzed by using the centre composite surface design of response surface method (RSM). Meanwhile the phase composition, appearance, microhardness, friction coefficient and corrosion resistance of the electroless coating were tested. The results show that the addition of Al²O³ and Si³N⁴ particles in the bath can increase the microhardness of the electroless composite coating. In a certain range, the increase of Al²O³ or Si³N⁴ particles in the bath causes the microhardness of the coating to increase, but the excessive addition of particles makes microhardness decrease; the electroless coating with two particles added will have a low coefficient of friction; and with respect to corrosion resistance, the addition of Al²O³ or Si³N⁴ particles will increase the corrosion resistance of the coating. Overall, the electroless coating with the Al²O³ content of 16 g/L and the Si³N⁴ content of 12.63 g/L has the better comprehensive performance.

Optimal design of the gear transmission system based on the modal response surface method

In order to conduct the lightweight optimization design of the gear transmission system, this paper uses the experimental design response surface method to construct the modal response explicit function of the gear transmission system based on the modal analysis results. Furthermore, the optimized design model of the gear transmission system (including gears, gear shafts, and bearings) is established on the base of the results of the modal response surface, and the optimized design model is solved and optimized through the Fmincon toolbox of MATLAB. By comparing the optimized results, it is shown that the optimization design method proposed in this paper can achieve the optimal design of the gear transmission system, which is of great significance to the optimization design of mechanical engineering.

Performance Analysis and Shape Optimization of an Impingement Microchannel Cold Plate

Optimization of liquid-cooled heatsinks (cold plates) is of critical importance due to their widespread application in high-performance electronic packages consisting of heterogeneous integrated systems, field programmable gate arrays (FPGAs), and on-chip hotspots. In this study, the thermo-hydraulic performance of a commercial microchannel impingement cold plate is analyzed in detail. Impingement cold plates are preferred over parallel flow cold plates due to their lower pressure drop where there is no restriction on space (i.e., where flow can enter perpendicular to the electronic board). Splitting the flow into two branches cuts the flow rate and the path into half, which leads to a lower pressure drop through the channels. Since the fins of the present commercial cold plate (considered as the baseline design) are tilted, the effect of the fin tilt angle on the hydraulic and thermal performance of the cold plate is also studied. The response surface method (RSM) is used to optimize the geometry of the fins and impinging inlet. The results of optimization show that hydraulic resistance can be reduced by 50% without a remarkable change in thermal resistance. The effect of the geometric parameters on the cold plate thermo-hydraulic performance is studied using the computational fluid dynamics results at the RSM design points. The variation in the cold plate coefficient of performance with the coolant flow rate and inlet temperature is compared for the baseline design and a selected optimal design. Finally, the effect of impinging inlet geometry on the chip temperature profile is also examined.

Preparation and in vitro quality evaluation of curcumin supersaturated self-nanoemulsion

In order to improve the supersaturation and maintenance time of drug dispersion in curcumin self-nanoemulsion(CUR-SNEDDS), precipitation inhibitors(PPIs) were introduced to prepare curcumin supersaturated self-emulsion(CUR-SSNEDDS). The composition of CUR-SNEDDS prescriptions was selected through the solubility test, the compatibility of oil phase and surfactant, the investigation of the emulsifying ability of the surfactant and the drawing of the pseudo-ternary phase diagram. Analytic hierarchy process was used in combination with central composite design-response surface method to optimize the prescription. The type and dosage of precipitation inhibitors(PPIs) were selected to maintain the supersaturated concentration and duration of CUR in artificial gastrointestinal fluids. At the same time, polarizing microscope was used to evaluate the crystallization inhibition effect and the quality and in vitro release behavior of CUR-SSNEDDS. The prepared CUR-SSNEDDS prescription was capryol 90-kolliphor RH40-transcutol HP-Soluplus(7.93∶66.71∶25.36∶5), with the drug loading of(65.12±1.25) mg·g~(-1). CUR-SSNEDDS was transparent yellow, and the nanoemulsion droplets were spherical with uniform distribution. The emulsification time was(21.02±0.13) s, the average particle size was(57.03±0.35) nm, the polydispersity index(PDI) was(0.23 ± 0.01), and the Zeta potential was(-18.10±1.30) mV. CUR-SSNEDDS significantly inhibited the generation and growth of crystals after in vitro dilution. The supersaturation could be maintained above 10 within 2 h, and the dissolution rate and degree of CUR in artificial gastrointestinal fluid were significantly increased. Soluplus could effectively maintain the supersaturated state of CUR and enhance CUR dissolution in vitro.

High yield and high concentration glucose production from corncob residues after tetrahydrofuran + H2O co-solvent pretreatment and followed by enzymatic hydrolysis

To obtain high yield and high concentration glucose from corncob residues (CRs), tetrahydrofuran (THF) + H2O co-solvent pretreatment was employed. The pretreatment parameters were firstly optimized by Box-Behnken Design of response surface method, and the maximum glucose yield (498.2 mg/g CRs) was obtained via enzymatic hydrolysis after pretreated under optimized conditions (53.7% THF concentration, 202.3 °C, 1.05 h). Then, the pretreated CRs under optimized conditions (optimized-CRs) were enzymatically hydrolyzed at high solid loading (15%–20%) and low enzyme input (5–8 FPU/g cellulose). The high concentration glucose production (128.6 mg/mL) was obtained from optimized-CRs after enzymatic hydrolysis at 20% solid loading with 10 FPU/g cellulose for 72 h, and then showed potential for reduction of enzyme input. Finally, the interactions between the 9 substrate-related factors and cellulose conversion were analyzed through correlation analysis, and found that Klason lignin remained in the cellulose-rich fractions and pseudo lignin condensed on the surface of the recovered substrate were the predominant inhibitors for enzymatic hydrolysis.

Optimization of process parameters for preparation of polystyrene PM2.5 particles by supercritical antisolvent method using BBD-RSM

The objective of this study is to optimize the process parameters for preparing polystyrene (PS) PM2.5 particles by supercritical antisolvent (SAS) method. Toluene was selected as the solvent and supercritical carbon dioxide (SC-CO2) was used as the antisolvent. The Box–Behnken design-response surface method was applied to investigate the effect of crystallizer pressure, PS massic concentration, flow ratio of CO2/solution and crystallizer temperature on the size and the distribution of PS particles, systematically. It is found that crystallizer temperature is the most significant variable on the size and the distribution of PS particles, followed by flow ratio of CO2/solution and PS massic concentration, and crystallizer pressure is the slightest significant factor. The particle size increases with the increase of crystallizer temperature. The optimum conditions are obtained as crystallizer pressure 9.8 MPa, PS massic concentration 1.6 wt%, flow ratio of CO2/solution 140 g/g and crystallizer temperature 309 K. Under these conditions, the PS particle with the size of 2.78 μm and a narrow size distribution has been prepared, meeting PM2.5 standard aerosols. The results suggest that it is feasible to produce PM2.5 standard aerosols by SAS.

Hydrothermal pretreatment and acid hydrolysis of coconut pulp residue for fermentable sugar production

Coconut pulp residue is the waste generated after the extraction of milk and oil. This material became an interest as feedstock for the production of biofuels and other bioproducts in a biorefinery context. The present study aimed to improve the release of sugar from coconut pulp residue through the optimization of sequential hydrothermal and acid pretreatment. An experimental design was constructed with the central composite design (CCD) response surface method using factors of the hydrothermal residence time of 20, 40, 60min and post-acid treatment concentration of 1%, 2% and 3% (v/v) in constant temperature and time of 121°C and 20min. Total sugar yields of 32.47, 27.51 and 26.72g/L were observed after hydrothermal pretreatment time of 20, 40 and 60min, respectively. Furthermore, when the pretreated solid residues were subjected to acid pretreatment, the results revealed an increment of 90% on reducing sugars after reaction with 1%, 2% and 3% H2SO4. Statistically, the optimum condition for the two-stage hydrolysis of coconut pulp residue was 60min hydrothermal pretreatment followed by 3% H2SO4 acid hydrolysis with maximal reducing sugar release of 120.71g/L. In addition, the degree of polymerization achieved was 1.2, indicating no further hydrolysis required. The current study demonstrates that two-stage pretreatment improves saccharification and provide sufficient sugars for the fermentation process.

Preparation and in vitro release of ginkgolide B nanosuspension

To prepare ginkgolide B nanosuspension(GB-NS), and investigate its dissolution behaviors in vitro. The miniaturized media milling method was used to prepare nanosuspensions, with average particle size and polydispersity index as the evaluation indexes. The formulation and process of GB-NS were optimized by single factor experiment and Box-Behnken design-response surface method. The morphology was observed by scanning electron microscope(SEM), and thecrystallinity of GB-NS was investigated by X-rays diffraction(XRD). The paddle method was used to study the dissolution of GB-NS in vitro. The mean particle size of optimized GB-NS was(180±7) nm, with a polydispersity index of 0.196±0.036. SEM showed that GB-NS was rod-like or irregular granular. XRD showed that the crystallinity of GB-NS was significantly reduced compared with GB raw material. The cumulative dissolution rate of GB-NS reached 90% in 30 min, which was higher than that of GB raw material. The findings suggested that the miniaturized media milling method was simple, efficient and feasible to prepare GB-NS. And the dissolution rate of GB was significantly improved by nanosuspension technology.

Optimization of concurrent production of xylanolytic and pectinolytic enzymes by Bacillus safensis M35 and Bacillus altitudinis J208 using agro-industrial biomass through Response Surface Methodology

Application of crude xylanolytic and pectinolytic enzymes in diverse industrial processes make these enzymes commercially valuable and demand their production process to be cost-effective. Out of four different agrowaste biomass, wheat bran (WB) and citrus peel (CP), when amended as fermentation substrates, respectively induced the highest xylanolytic enzymes and pectinolytic enzymes from both, B. safensis M35 and B. altitudinis J208. Further, the simultaneous amendment of WB and CP yielded concurrent production of these cellulase free xylanolytic and pectinolytic enzymes. Hence, the quadratic model was developed using the Central Composite Design of Response Surface Method (CCD-RSM). The model gave the concentration values for WB and CP substrates to be amended in one single production medium for obtaining two optimized predicted response values of xylanase activity and pectinase activity units, which were further practically validated for the xylanase and pectinase production responses from the optimized production medium (OPM). These practically obtained response values from OPM were found to be in accordance with a range of 95% predicted intervals (PI) values. These observations verified the validity of the predicted quadratic model from RSM and suggested that both xylanase and pectinase enzymes can be induced concurrently from both of the bacterial strains.

Strengthening Behavior of Cemented Paste Backfill Using Alkali-Activated Slag Binders and Bottom Ash Based on the Response Surface Method.

A new type of cemented paste backfill (CPB) was prepared by using the bottom ash (BA) from a thermal power plant as an aggregate, alkali-activated slag as a binder, and an air-entraining agent as an admixture. Based on the central composite design (CCD) response surface method, the mix ratio was optimized, and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) was performed on the optimal mix ratio. ImageJ software was utilized to determine the porosity of the experimental samples at various curing ages. The results indicate that the optimal mix ratio of the aggregate-binder ratio is 3.28, the alkali dosage is 3%, the solid content is 67.44%, and the air-entraining agent dosage is 0.1%. As the curing age increases, the porosity of CPB gradually decreases. A calcium aluminosilicate hydrate (C-A-S-H) gel is the main hydration product of alkali-activated slag. At the beginning of the hydration reaction, the slag gradually dissolves, and the C-A-S-H product binds the BA together. At 14 d, complete calcium hydroxide (CH) crystals appeared in the hydration product. Finally, the degree of C-A-S-H crystallization increased further to form a dense structure.

Optimization on the Injection Molding Propypopylene Parameters Using Central Composite Design for Minimizing Defects

This study aims to simultaneously forecast and investigate the optimization process characterization of the design of controlled parameters in the injection process of polypropylene molding including injection pressure combination, clamping force, injection temperature, injection speed, and holding time, and their interaction to produce qualified plastic by minimizing defects. The experimental methods used the central composite design of response surface method with five factors and a variety of levels. This method is more effective because it is an improvement on and a development from previous studies—especially those related to the plastic molding process. Additionally, it can simultaneously predict and optimize the obtaining of the highest quality plastic products as well as minimizing defects. The results are in the form of a combination of control level factors and interactions among the factors that generate the robust output of plastic products with minimum defects. Moreover, the optimum settings of the parameters provides a global solution at an injection temperature of 275°C, injection pressure of 75 bar, injection speed of 98%, clamping force of 88 tons, and a holding time of 8 seconds to generate a response to product probability defects by 0.0062. The benefit is that it can reveal the behavior and characteristics of parameter design and their interactions in the plastic injection molding process to produce qualified plastics and minimize product defects.

Experimental Study on Picking Unit Parameters of Brush-rolling Cotton Harvester

In order to find the optimal combination of the picking unit parameters of the brush-rolling cotton harvester, the parameters optimization experiment were carried out. Taking the rotary speed of brush roller, the working velocity, and the number of brush plates as the experimental factors, the collect rate and the loss rate of struck cotton as the performance evaluation indexes, the quadratic regression orthogonal rotational combing design experiment was carried out. The Central Composite Design response surface method was used to establish the regression model of experimental factors and evaluation indexes, and analyze the influence of each factor on evaluation indexes. Using multi-objective optimization, the optimal parameter combination is as follows: the rotary speed of the brush roller is 350 r/min, the working velocity is 0.5 m/s, the number of brush plates is 6 rows. After the optimization test, the collect rate is 95.58%, and the loss rate of struck cotton is 1.22%. The field verification test shows that the collect rate of 4MSG-3 brush-rolling cotton harvester is 92.86%, and the loss rate of struck cotton is 1.26%. The relative error between verification test results and parameter optimization value is less than 5%, which verifies the reliability of the regression model. This study provides a theoretical basis for optimizing and improving the picking unit’s parameters of the brush-rolling cotton harvester.

Development of HPLC Method for Stress Testing of Combination of Two Drugs Using Design of Experiment Concept

This study was conducted to develop, an High Performance Liquid Chromatography using photodiode array detector (HPLC-PDA) method to analyse the samples generated by the stress testing of antifilarial combination (albendazole and diethylcarbamazine citrate) in the solution state. The concept of Quality by Design (Design of Experiment, DoE) approach was used for the development. For the separation of the drugs and its degradation products (DPs), DoE was applied in two stages, i.e., primary parameter stage where factors having major effect were selected. This stage gives us CQA (Critical Quality Attribute) which along with minor factors affecting were varied to get the secondary design. For each of the stage a different design was selected; for primary stage IV optimal design (Response Surface Method) was selected whereas for secondary stage, Taguchi orthogonal array design was selected. The major primary parameters affecting the HPLC method as screened by preliminary studies were the buffer pH, organic modifier (methanol or acetonitrile), initial hold time (start of gradient) and gradient time. The primary stage was completed successfully. The results were compiled in form of resolution of peak from next peak and analysed by DoE. The process fixed the values for buffer pH (4.38), organic modifier (acetonitrile) and gradient time (30 min). The CQA from primary run was initial hold time. This parameter along with other parameters: initial and final concentration of organic modifier, buffer type (phosphate or acetate), buffer strength (mM) and oven temperature were further varied and samples withdrawn were analysed. The data of secondary design was compiled in the form of resolution (R), analysed by Design Expert and final value for secondary parameter for HPLC method were fixed. The resolution of the peaks for some secondary runs was sufficient reflecting some type of interaction between the drugs and/or degradation products.

Design, Preparation, and Characterization of Dioscin Nanosuspensions and Evaluation of Their Protective Effect against Carbon Tetrachloride-Induced Acute Liver Injury in Mice.

The purpose of this study was to prepare a dioscin nanosuspension (Dio-NS) that has a better distance and high solubility for oral administration and to evaluate its hepatoprotective effects. Optimal primary manufacture parameters, including shear time, shear speed, emulation temperature, pressure, and cycles of homogenization, were determined by single-factor experiments. The concentrations of dioscin, SDS, and soybean lecithin were optimized using the central composite design-response surface method, and their effects on the mean particle size (MPS) and particle size distribution of Dio-NS were investigated. Characterization of the Dio-NS formulations included examinations of the surface morphology and physical status of dioscin in Dio-NS, the stability of Dio-NS at different temperatures, in vitro solubility, and liver protective effect in vivo. Under optimal conditions, Dio-NS had an MPS of 106.72 nm, polydispersity index of 0.221, and zeta potential of −34.27 mV. Furthermore, the proportion of dioscin in Dio-NS was approximately 21.26%. The observation of particles with a spherical shape and the disappearance of crystalline peaks indicated that the physical and chemical properties of Dio-NS were altered. Furthermore, we observed that the dissolution of Dio-NS was superior to that of a physical mixture and Dio-GZF. Moreover, Dio-NS was demonstrated to have a protective effect against CCl4-induced acute liver damage in mice that was equivalent to that of silymarin (a positive control drug) at the same dose. The good hepatoprotective effect of our Dio-NS preparation can provide a theoretical basis for investigating its absorption mechanisms in the body.

Controllable Superhydrophobic Stainless Steel Surfaces Fabrication by Femtosecond Laser

Abstract Ultrafast laser processing has emerged as important tool for micro- and nanoscale fabrications. It is also used to create self-organized microstructures with nanoscale features on surfaces. Fabrications of superhydrophobic surfaces induced by femtosecond laser have many applications that include anticorrosion, self-cleaning, and drag reduction. We created hydrophobic surfaces on stainless steel surfaces by producing a hierarchical nano–microstructure with ultrafast laser ablation. Periodic nano–microstructures with different topographies were fabricated on stainless steel AISI 304 surface using a femtosecond laser with a pulse duration of 100 fs and a wavelength of 800 nm. Ablation was performed in the open air with no subsequent treatment. In this study, a three-level Box–Behnken design of response surface method was used to investigate and optimize the process parameters for hydrophobic surfaces. The laser-machined hierarchical nano–microstructures were examined using a scanning electron microscope and an opto-digital 3D microscope. The wetting of surfaces was measured in terms of the contact angle of a water droplet using a digitized goniometer. The contact angle of laser-modified surfaces was changed from a hydrophilic behavior to a hydrophobic one without any surface coatings. The effect of pulse energy was found to be significant on the output characterization. The results revealed that the average pulse energy range of 0.035–0.05 mJ at 10,000 Hz with a scanning speed of 10–100 mm/s and line separation of 10–30 μm produced hydrophobic surfaces with the apparent contact angle of 110–135°. We demonstrated a simple way to tune hydrophobicity using femtosecond laser surface modification in a single step with no subsequent post treatment.

Optimization of formulation and preparation technology of lutein liposomes by central composite design-response surface method

Optimization of formulation and preparation technology of lutein liposomes by central composite design-response surface method

Optimization of bioleaching high-fluorine and low-sulfur uranium ore by response surface method

In order to optimize conditions for bioleaching of the high-fluorine and low-sulfur uranium ore by the test acidophilic consortiums, the central composite design method and response surface method were applied to study the relationships between pyrite addition, pulp density, temperature and uranium recovery rate, respectively. The results showed that the pulp density, pyrite addition and temperature had a significant impact on the uranium recovery rate. The predicted optimum uranium leaching conditions were 2.20% of pyrite addition, 7.69% of pulp density and 31.90 °C of temperature, respectively. The actual uranium leaching rate under the optimal conditions was 94.84%, which was consistent with the predicted values with the model (95.21%). The results were of great significance for a large-scaled bioleaching practice of the high-fluorine and low-sulfur uranium or low-grade uranium ore.

Parametric optimization of a steering system based on dynamic constraints collaborative optimization method

The steering system has an important impact on the energy consumption, maneuverability, and driving stability of vehicles. In order to improve the system’s comprehensive performance, this research takes electro-hydraulic active steering (EHAS) system as the design object and utilizes the dynamic constraints collaborative optimization (DCCO) method for the parametric optimization of the EHAS system. Steering modality is combined with dynamic performance evaluation indices such as steering energy consumption, steering road feel, steering sensibility, and steering stability, to evaluate the comprehensive performance of the EHAS system. Then, a hierarchical multidisciplinary optimization model of EHAS system is established based on DCCO method, which takes the comprehensive performance of steering system as the overall system and steering energy consumption, steering road feel, steering sensibility, and steering modality as subsystems respectively. The multidisciplinary performance evaluation indices of EHAS system are derived for the first time, among which the evaluation index of steering modality is obtained by combining of design of experiments (DOE) design method and response surface method. The optimization results show that the EHAS system optimized by DCCO method can effectively improve steering energy consumption, steering road feel, and steering sensibility.