Composite Design Of Response Surface Method Research Articles

Modelling and optimization of multiple replacement of supplementary cementitious materials for cement composite by response surface method

Supplementary cementitious materials are beneficial in improving performance and lessening the cement consumption with highly lessening CO2 emission. Many researchers used blast furnace slag, bentonite, and active limestone separately or two of them together to improve the performance of cementing materials, however, it is not well known how all react together in cement composite materials. So, the present study used modeling and optimizing the replacement of blast furnace slag, raw bentonite, and active limestone each by the doses of 0 to 20% to maximize strength and minimize the fresh bulk density of cementing materials by central composite design-response surface method (CCD-RSM). The results found, the employment of blast furnace slag, bentonite, and active limestone in the cement composite materials generally lessens the early strength compared to the control mixture. However, the replacement of blast furnace slag and active limestone by 20% significantly improves the 28-days compressive strength while employing raw bentonite by 20% reduced compressive strength by 6.45% compared to the control mixture. However, blending raw bentonite with active limestone by half improved the compressive strength. Besides these, the substitution of bentonite and active limestone reduces the fresh bulk density and flexural strength than the control mixture. Generally, the study optimized depending on the criteria of maximizing strength and minimizing fresh density and found the mix design replacement of blast furnace slag 1.01%, raw bentonite 5.30%, and active limestone 20% that improves 28 days compressive strength simultaneously reduces fresh bulk density in addition to replacing more than 54 different optimized design mix results.

Preparation and quality evaluation of total flavonoids microemulsion of "Pueraria lobata-Hovenia dulcis"

The effective components of flavonoids in the "Pueraria lobata-Hovenia dulcis" drug pair have low bioavailability in vivo due to their unstable characteristics. This study used microemulsions with amphoteric carrier properties to solve this problem. The study drew pseudo-ternary phase diagrams through titration compatibility experiments of the oil phase with emulsifiers and co-emulsifiers and screened the prescription composition of blank microemulsions. The study used average particle size and PDI as evaluation indicators, and the central composite design-response surface method(CCD-RSM) was used to optimize the prescription; high-dosage drug-loaded microemulsions were obtained, and their physicochemical properties, appearance, and stability were evaluated. The results showed that when ethyl butyrate was used as the oil phase, polysorbate 80(tween 80) as the surfactant, and anhydrous ethanol as the cosurfactant, the maximum microemulsion area was obtained. When the difference in results was small, K_(m )of 1∶4 was chosen to ensure the safety of the prescription. The prescription composition optimized by the CCD-RSM was ethyl butyrate(16.28%), tween 80(9.59%), and anhydrous ethanol(38.34%). When the dosage reached 3% of the system mass, the total flavonoid microemulsion prepared had a clear and transparent appearance, with average particle size, PDI, and potential of(74.25±1.58)nm, 0.277±0.043, and(-0.08±0.07) mV, respectively. The microemulsion was spherical and evenly distributed under transmission electron microscopy. The centrifugal stability and temperature stability were good, and there was no layering or demulsification phenomenon, which significantly improved the in vitro dissolution of total flavonoids.

Performance assessment of mechanical properties of green normal strength concrete produced with metakaolin-cement coated recycled concrete aggregate for sustainable construction

Reusing demolished concrete waste is a promising alternative to natural aggregate for resource conservation and achieving sustainable environment. However, there is a need to improve their quality and performance in new concrete. Therefore, this study aims to examine the mechanical performance of normal strength concrete containing metakaolin-cement coated recycled concrete aggregate (RCA). Three mixture batches were produced at water-cement ratios (w/c) of 0.25 and 0.45. The first batch is control mix, while the second and third batches contained uncoated RCA and metakaolin-cement coated RCA (TRCA) respectively. Materials characterization and workability of fresh concrete mixes were carried out. Compressive and split tensile strengths and water absorption tendency of hardened samples were determined. Morphology of selected concrete samples was analysed with scanning electron microscopy (SEM) with energy dispersive x-ray (EDX). The experimental results were further analysed with central composite design (CCD) response surface method. Results show improvements in the physical properties of RCA aggregates and declining trends in slump values. However, relative to the control mixes, concrete mixes containing TRCA exhibited significant improvement in strength performance and low water absorption tendency compared to RCA concrete mixes. This was corroborated by the response surface models showing that both w/c ratio and TRCA amount significantly influenced the strength and water intake performance of the concrete. The study demonstrated that TRCA can be deployed as an alternative for natural coarse aggregate up to 50% substitution in making normal concrete for structural purposes.

Study on the Performance and Mechanism of Cold-Recycled Asphalt Based on Permeable Recycling Agent.

In order to investigate the influence of recycling agent composition on the recycling effect of aged asphalt in the cold recycling process, the design and optimization of cold recycling agent composition were performed through the central composite design-response surface method combined with the dynamic shear rheometer (DSR) test and the bending beam rheometer (BBR) test. The molecular weight distribution and component changes in aged asphalt before and after the addition of a cold recycling agent were also analyzed by gel permeation chromatography (GPC) and hydrogen-flame ionization test. The results showed that the permeable cold recycling agent has a recycling effect on the aged asphalt, but its effectiveness is greatly affected by recycling agent composition. The best recycling effect was achieved when the ratio of aromatic oil and penetrant in the cold recycling agent was 61.2:38.8, respectively. In terms of the recycling agent and aromatic functional groups in the aromatic oil, the aromatics in the recycling agent are derived from the aromatic oils, and the penetrant is only fused and permeated with the aromatic oils. After the admixture of the cold recycling agent, the penetrant in the recycling agent allows the aromatic oil to enter the aged asphalt at room temperature. The light components volatilized by aging are replenished, allowing the aged asphalt to recover some of its properties.

Triptolide nanoemulsion gel as a transdermal drug delivery system: preparation, pharmacokinetics, and rheumatoid arthritis evaluation.

This study aimed to develop and evaluate triptolide nanoemulsion gels (TP-NE gels) as a transdermal drug delivery system. TP-NE was prepared and optimized via emulsification and the central composite design response surface method. The optimized TP-NE gel was evaluated in vitro and in vivo. TP-NE gel microstructure, in vitro and in vivo pharmacokinetics, and anti-rheumatoid arthritis effects were studied to evaluate the feasibility of its percutaneous administration. The Optimized TP-NE was observed using a Malvern Autosizer Nano ZS 90 inspection system and a transmission electron microscope (TEM). The nanoemulsion had an average size of 162.9 ± 0.281 nm, a polydispersity index of 0.272 ± 0.024, a zeta potential of -30.03 ± 2.01 mV, and mostly spherical and uniform morphology. In addition, the TP-NE gel pharmacokinetics, assessed via a skin-blood two-site synchronous microdialysis, revealed that TP was higher in the skin than in the blood. TP-NE gel is crucial in reducing knee edema, inhibiting inflammation, and treating rheumatoid arthritis by regulating tumor necrosis factor-alpha, interleukin-1β, and -6 levels. The TP-NE gel is a promising local delivery method for rheumatoid arthritis (RA)-associated edema and inflammation and can serve as a prospective platform for percutaneous TP administration.

Optimization of technological parameters in ultrasonic welding of the polypropylene fabric using Taguchi and FCCCD methods

Ultrasonic welding is a welding method that has been applied for welding nonwoven fabrics, with many advantages such as fast speed, high reliability, easy automation and especially less pollution to the environment. This paper studies the optimization of technological parameters in the welding process such as welding time, pressure, and weld shape on the breaking strength of ultrasonic welding of Polypropylene (PP) nonwovens. To evaluate the influence level and find the reasonable technological parameters domain in the paper, the Taguchi method is used in combination with the face-centered central composite design (FCCCD) response surface method. The research results have determined the regression equations used to calculate the breaking strength for each weld shape as well as the optimal domain for the main technological parameters, ensuring the breaking strength of the weld. There are different degrees of influence of technological parameters (shape of the weld zone, welding time and welding pressure) on the breaking strength of ultrasonic welds. Among them, the influence level of welding time t is 45.31 %, the weld shape is Pattern 2 with the rate of 30.03 %, and the welding pressure is 24.66 %. Carrying out a verification test with the welding parameters: t=1.6 s, p=3.1 kgf/cm2, two patterns ( Pattern 2 and Pattern 3), the result of breaking strength for patterns was achieved. Pattern 2 has a difference of 1.19 % between the regression equation results and the actual experimental results, while the figure for Pattern 3 is 0.77 %. From these results, it is possible to select the appropriate technological parameters for ultrasonic welding equipment when processing products from nonwoven fabrics to ensure the highest quality and productivity

Preparation of inorganic binder-stabilised material with iron tailings: strength formation and gradation optimisation

This study focuses on mechanical strength and gradation optimisation of inorganic binder-stabilised material with iron tailings for pavement engineering. The mechanical strength and compatibility of iron tailings mortar with various inorganic binders were explored. Mechanical strength formation of iron tailings mortar was analysed using hydration products, micromorphology and microstructures. Composition optimisation of inorganic binder-stabilised material with iron tailings was discussed using the central composite design-response surface method. Results showed that the mechanical strength formation of iron tailings mortar is primarily dependent on ettringite and calcium silicate hydrate (C–S–H) gels. Iron tailings mortars with an appropriate amount of lime or fly ash replacement of cement exhibit a denser structure and adequate pore structure distribution that help improve their mechanical properties compared with cement iron tailings mortars. To balance the amount of iron tailings and the strength of cement-stabilised material, optimal application conditions were proposed for different levels of highways.

Design and optimization of superabsorbent hydrogels based on acrylic acid/2‐acrylamido‐2‐methylpropane sulfonic acid copolymers

AbstractAlthough acrylic acid‐based superabsorbent hydrogels (SAHs) are widely used in hygiene and personal care applications, the low degrees of true ionization in such SAHs under practical application places a limit on the degree of superabsorbency that can be achieved. Herein, the preparation and optimization of SAHs based on copolymers of acrylic acid (AA) with 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS), a strong acid comonomer that remains ionized at all relevant physiological pH values, is described. AA‐AMPS recipes optimized using a central composite design response surface method demonstrate significantly enhanced absorbance under load (AUL) values (>15–20% increase) and comparable centrifuge retention capacity (CRC) values compared to the corresponding AA‐only controls while maintaining strong mechanics even in the swollen state (as much as twice the modulus of the commercial AA‐based superabsorbent). The simplicity of this recipe, coupled with the reproducible achievement of the improved superabsorbency properties using a small adaptation of the commercial SAH synthesis protocol, makes AA‐AMPS superabsorbent hydrogels potential candidates for use in commercial hygiene products.

Preparation and process optimization of microbial organic copper as a feed additive

ABSTRACT As an essential trace element for animals, copper significantly contributes to the growth and health of animals. Compared to inorganic trace elements, organic trace elements are better supplements; notably, they are acquired through microbial transformation. Therefore, we screened for copper-enriched microorganisms from high copper content soil to obtain organic copper. Sodium diethyldithio carbamate trihydrate was applied as a chromogenic agent for determining micro amounts of intracellular copper through spectrophotometry. In total, 50 fungi were isolated after the successful application of the screening platform for copper-rich microbes. Following morphological and molecular biology analyses, the N-2 strain, identified as Aspergillus niger sp. demonstrated showed better copper enrichment potential than others. Notably, the strain tolerance to copper was nearly thrice that of Saccharomyces cerevisiae, up to 1600mg/L. The content of the organic bound copper was 22.84mg Cu/g dry cell. Using the Central Composite Design (CCD) response surface method, we optimized the fermentation condition (inoculation amount, 13%; temperature, 28(C; pH, 5.0). Compared to the original strain results under the single factor fermentation condition, we reported an increase by 24.18% under the optimized conditions. Collectively, these findings provide a reference for uncovering new and low-cost organic copper additives.

Selective Separation of Arsenic from High-Arsenic Dust in the NaOH-S System Based on Response Surface Methodology

The selective separation of arsenic in the NaOH-S system from arsenic dust containing Pb, Sb, and Zn was studied by central composite design response surface method in this investigation. The results indicated that the presence of elemental sulfur can prevent lead and antimony leaching from arsenic dust effectively. The optimal leaching conditions were established as follows: 3.0 mol/L sodium hydroxide, 10 g/L sulfur, leaching temperature 95 °C, leaching time 2.0 h, liquid to solid ratio 6, and stirring speed 400 r/min. The arsenic leaching efficiency can reach 99.37% under the optimized conditions, meanwhile 98.39% of Sb, 99.74% of Zn, and 99.91% of Pb remained in the leach residue with the arsenic content < 0.1%. Oxidation-cooling crystallization has been used to recover sodium arsenate from the leaching solution under the optimal reaction conditions: C(H2O2)/C(As) 0.45, oxidation temperature 50 °C, stirring speed 200 r/min, crystallization temperature 30 °C, and crystallization time 120 min. This work presents a novel route for selective separation of arsenic and potential recycling lead and antimony from the arsenic dust in the NaOH leaching system with adding elemental sulfur.

Ice Cream Cup Production Using Purple Sweet Potato (Ipomoea batatas L. Poir) as a Substitute Ingredient

This study aimed to define the proportion of purple sweet potato addition as a substitute ingredients of the ice cream edible cup and to reduce its baking time. This study was designed using Central Composite Design (response surface method) with 2 factors, i.e. the proportions of purple sweet potato powder and the baking time with water content, cup resistance, and fracturability as the responses. The main component of purple sweet potato ice cream cup is starch and cellulose as shown by the characteristic of the functional group which are C-H of alkene, C= C of alkyna, C = O of aldehyde/ketone/carboxylic acid/ester, C-C group of aromatic ring, C-O alcohol/ether/carboxylic acid/ester, C-H of aromatic ring and C-H of alkene. The result of the study showed that the the optimum proportion of purple sweet potato powder was 75% and the baking time was 45 minutes with the water content of 4.37%, cup resistance of 253.64 minutes, fracturability of 0.2125 N, protein content of 4.79%, and carbohydrate content of 4.66%. Based on the consumer’s acceptance aspect, purple sweet potato ice cream cup was the mostly liked because of its texture and flavor, meanwhile its color and aroma was the mostly disliked.

Impact and significance of pretreatment on the fermentable sugar production from low-grade longan fruit wastes for bioethanol production

The feasibility of bioethanol production from low-grade longan fruit waste material was recently studied as a novel substrate for bioethanol production. First, hydrothermal pretreatment followed by enzymatic hydrolysis converted both the cellulosic and hemicellulosic biomass of the low-grade longan fruit wastes into fermentable sugars, which eventually produced ethanol by yeast fermentation. Therefore, an optimal condition of hydrothermal residence time and pretreatment concentration was determined to obtain the high release of sugars. An experimental design was constructed with the Central Composite Design (CCD) response surface method using factors of the hydrothermal residence time and pretreatment concentration in constant temperature and time. The results revealed optimum reducing sugar yield of 240.396 g/L (R2 = 0.9989), sugar productivity of 240.396 g/L.day (R2 = 0.9763), and sugar yield coefficient of 24.04 g/g (R2 = 0.9989). The highest ethanol yield (16.74 g/L) was achieved at 24 h of fermenting time. These results show that low-grade longan fruit wastes are an excellent feedstock for producing ethanol that could be either used as biofuel or as a beverage.

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.

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.

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.

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.

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.

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.

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.