Box-Behnken Experimental Design Method Research Articles

Optimization of the extrusion parameters for the production of lentil-quinoa extrudates enriched with pumpkin.

This study aimed to develop a protein-fiber-rich extruded product based on yellow lentil, quinoa, and pumpkin flours. The final product quality is affected by formulation and extrusion parameters. Therefore, the effect of the pumpkin-flour ratio (A: 25-75%) and feed moisture content (C: 14-22%) besides barrel screw speed (B: 120-180 rpm) on the physical attributes of extrudates was investigated. Box-Behnken experimental design and stepwise-response surface method were used to analyze the effects of various process variables and ingredients on extrudates. The pumpkin-flour ratio had a significant positive correlation with bulk density (BD), water solubility index (WSI), and oil absorption index. Whereas the correlation between pumpkin-flour ratio with hardness, porosity, expansion ratio (ER), and water absorption index (WAI) was negative (P < 0.05). The feed moisture content positively affected the water activity (aw) and WAI and negatively affected the harness of samples (P < 0.05). The screw speed had a positive effect on ER, porosity, and WSI, whereas it negatively influenced the hardness, BD, and aw. By increasing the pumpkin-flour ratio, air cell size and wall thickness of samples had been decreased. The results showed that 44.2% pumpkin flour, 22% feed moisture, and 172.1 rpm screw speed gave an optimized product. There was no significant difference between predicted and experimental values (except for ER). The optimized snack was a good source of fiber (around 15%), protein (17.3%), and antioxidants (TPC = 15.28 mg GAE.g-1 and antiradical scavenging activity (DPPH) = 33.66%). The caloric value of the optimized snack was 362.6 cal.100g-1. The current formulation can be considered as the base of snack food or plant-based meat alternatives.

Experimental study on ultrasonic-assisted electrochemical polishing of NiTi alloy

NiTi alloy has a wide range of applications due to its unique superelasticity and shape memory, the superelastic function of NiTi alloy made it had been applied in building shock absorption, advanced bearings and other scenes, the shape memory function made it also applied in the fields of aerospace engine heat exchanger, cardiac medical stent and so on. In order to made NiTi alloy better applied in practice and improve its surface quality, it was crucial to polish it. In this paper, a new method of ultrasonic-assisted electrochemical polishing of NiTi alloy was innovatively proposed, and an ultrasonic electrochemical polishing device was built independently. The effects of ultrasonic amplitude, voltage and temperature on roughness were explored by Box-Behnken experimental design method. The results show that after ultrasonic-assisted electrochemical polishing, the roughness Ra had been reduced from about 2 μm to the minimum of 0.048 μm. The surface quality of NiTi alloy was improved. The impact of micro-jet of cavitation bubble on NiTi alloy mainly occurs in the early stage, and the equivalent stress on the surface of NiTi alloy was annular, showing an increasing and decreasing trend. In the whole ultrasonic electrochemical polishing solution, a large number of micro-jets will impact the surface of NiTi alloy, thus realizing the material removal. This study enhances traditional electrochemical polishing techniques by integrating ultrasonic energy fields, thus broadening the scope of electrochemical polishing applications. Additionally, it presents a novel approach and establishes a foundation for the polishing of NiTi alloys with intricate geometries in additive manufacturing.

Optimization of mix proportions for hybrid fiber engineered cementitious composites based on Box-Behnken design response surface model

In this paper, basalt fiber (BF) and polyethylene fiber (PE) were mixed into cement matrix to prepare a new hybrid fiber Engineered Cementitious Composite. The Box-Behnken experimental design method within the Response Surface Methodology (RSM) was employed, the effects of water-binder ratio, sand-binder ratio and fiber content on compressive strength, flexural strength and equivalent bending toughness of hybrid fiber ECC were studied. Analysis of variance (ANOVA) was used to verify and optimize the model equation, and the ratio of water-binder ratio 0.2, sand-binder ratio 0.35, BF content 1.25%, PE content 1% was obtained. The results show that the synergistic effect of PE and BF has a favorable effect on the mechanical properties of hybrid fiber ECC. PE can achieve high energy absorption and maintain high strain capacity of matrix. BF increases the strength of the specimen. When the BF content increases from 0.9% to 1.2%, the compressive strength increases by 9.6%. The fiber content is highly sensitive to flexural strength and equivalent bending toughness, and the significance level of each factor is more than 95%. The significance level of each factor is BF content > sand-binder ratio > water-binder ratio. The experiment verified that the established prediction model has high accuracy, and the relative error between the optimized RSM value and the experimental value is less than 5%. To provide a certain reference for the design of ECC mix proportions for preparing multi strength and multi toughness series.

Design and Experiment of Grain Lifter for Sorghum Harvester

In order to solve the problems of grain lifter in sorghum harvesting, such as ear loss and serious crop leakage loss, combined with the physical and mechanical characteristics of sorghum, the segmented and reverse spiral grain lifter for sorghum harvesting and cutting table was developed, and the design method of the main structural parameters of the grain lifter was determined. The comparative test of the working effect of the clasp showed that the working effect of the cutting table with the clasp was better than that without the clasp, which effectively reduced the harvest loss of the cutting table. By using Box–Behnken experimental design method, the influence law of forward speed, tilt angle, and rotation speed of grain lifter on the rate of ear loss and harvest loss in sorghum harvesting was investigated. The regression mathematical model and response surface of the rate of ear loss and harvest loss and analysis factors were established, and the optimal working parameters of the grain lifter were determined. The forward speed was 0.8 m/s, the tilt angle of the grain lifter was 28°, and the rotation speed of the grain lifter was 330 r/min. Under these conditions, the spike loss rate was 2.01, the leakage loss rate was 2.19, and the error with the theoretical value was less than 3%, which proved the rationality of the optimized combination parameters. In the harvest of crooked and fallen sorghum, the grain lifter can effectively reduce the loss of sorghum head drop and lodging leakage, ensure the reliability of the cutting table, and achieve low loss and efficient harvest of sorghum.

Modelling and optimization of bovine serum albumin adsorption on calcium bentonite using box-behnken experimental design method

The purpose of this study is to investigate and optimize the process parameters for bovine serum albumin (BSA) adsorption onto calcium bentonite (CaB) using the Box-Behnken experimental design method. Calcium bentonite was characterized using FT-IR, SEM, XRD, zeta potential measurements, and Boehm titration methods. The BSA adsorption capacity of calcium bentonite was modelled with respect to pH (2.8, 4.8, and 6.8), temperature (25 °C, 32.5 °C, and 40 °C), and initial protein concentration (0.1–1.2 mg ml−1) using the Box-Behnken experimental design method. The Design Expert 13.0 software was used to optimize the process conditions and obtain three-dimensional response surface graphs. A regression model, which gives the relationship between the process parameters and BSA adsorption capacity, was obtained using Design Expert software. The developed model showed that the most effective parameter on adsorption was the initial protein concentration followed by pH and temperature. The maximum adsorption capacity was obtained about 171 mg/g under optimal conditions (pH 4.8, 40 °C, and 1 mg ml−1 of initial BSA concentration). BSA adsorption onto CaB fit the pseudo-second order kinetic model. This study showed that process parameters for BSA adsorption can be effectively investigated and optimized using the Box-Behnken experimental design method with a fewer number of experiments.

Simulation and Optimization Experiment: Working Process of a Cleaning Device for Flax Combine Harvester

The aim of this study was to investigate the effects of different working parameters on the cleaning efficiency of a cleaning device during the separation and cleaning process in a flax joint harvesting machine. To achieve this objective, CFD–DEM joint simulation technology was used to construct a CFD model of the cleaning device and a DEM model of the discharged flax material; the simulation results show the flax cleaning process. The Box–Behnken experimental design method was used to establish a mathematical model between the vibrating sieve frequency, vibrating sieve amplitude, fan wind speed, seed impurity rate, and cleaning loss rate to find the optimum combination of cleaning equipment parameters and to conduct a field verification test. The simulation test results show that, when the vibrating sieve frequency is 6 Hz, the vibrating sieve amplitude is 14.42 mm, the fan wind speed is 5.96 m/s, and the machine cleaning effect is the best; the simulation test was measured following a seed impurity rate of 2.97% and cleaning loss rate of 2.17%. The field test verification results show that, after optimizing the working parameters of the cleaning device, the cleaning loss rate is 3.58% and the impurity rate of the grain combine harvester is 3.16%, thus meeting the national and industry requirements. The test results and simulation results are highly consistent with the model, thereby verifying the reliability of the model. The results of the study provide a reference for the design and performance optimization of the flax combine cleaner.

Optimization of Guide Vane Centrifugal Pumps Based on Response Surface Methodology and Study of Internal Flow Characteristics

The methodologies of computational fluid dynamics (CFD) and response surface method (RSM) were integrated to uncover the optimal correlational framework for intricate hydraulic geometric parameters of guide vane centrifugal pumps. Parameters such as blade number, blade wrap angle, blade outlet angle, and relative axial distance between the guide vane and impeller, as well as radial distance, are embraced as optimization design variables. Meanwhile, pump head and efficiency were chosen as responsive variables. An analysis of 46 sets of hydraulic performance data was carried out by using the Box–Behnken experimental design method. Subsequently, response surface approximation models were established between hydraulic parameters and the efficiency, as well as the head. The optimal design point was predicted and a simulation of the hydraulic characteristics for the optimal scheme was conducted; the errors were 0.846% for head and 0.256% for efficiency between the simulation results with predicted results from RSM. The optimized model demonstrates noteworthy enhancements in hydraulic performance in comparison to the original model. By analyzing the internal flow of the optimized model under transient conditions, it was found that, as the internal flow of the flow passage components is relatively disordered at small flow rates, the amplitude of pressure pulsation is affected a lot. At other flow rates, the inside pressure pulsation waveform exhibits pronounced periodicity, and the primary causes of pressure pulsation in various flow components are not the same. Wall dissipation and turbulent dissipation emerge as significant contributors to the entropy generation in this centrifugal pump. The magnitude of entropy generation is correlated with the flow rate and the structural configuration of the pump’s components. High-entropy regions concentrate around the leading and trailing edges of the blades.

Research on a new-designed Venturi ejector and dazomet particle motion characteristics for dilute-phase pneumatic conveying systems based on CFD-DEM

To disperse dazomet, a commonly used soil fumigant for soil disinfection, over large soil surfaces, dilute-phase pneumatic conveying can be utilized. Currently, most research has focused on pneumatic conveying systems for large particles, such as coal conveying or pneumatic seeding However, there has been almost no research on the dilute-phase pneumatic conveying of dazomet particles. Therefore, a coupled simulation model based on computational fluid dynamics and discrete element method (CFD-DEM) was established to study the effect of the structural parameters of the Venturi ejector on the motion of particles and airflow fields variation characteristics for the pneumatic conveying system of dazomet particles. Based on the Box–Behnken experimental design method, a 3-factor and 3-level response surface simulation experiment was carried out by selecting the contraction angle, throat diameter, and diffusion angle of the Venturi ejector as factors. The suction-flow ratio, average velocity of particles, average coordinates of particles in the vertical direction, and corresponding standard deviation at the outlet of the pipeline were chosen as response indexes. Multiple linear regression models were established between each factor and response index. The simulation results showed that the impact of factors on the 4 response indexes from strong to weak were throat diameter, contraction angle, and diffusion angle. With decreasing throat diameter, the suction flow ratio and average velocity of the particles increased. The average coordinates of the particles in the vertical direction decreased, while the standard deviation increased, indicating that the pneumatic conveying performance of the system increased. The optimal structural parameters for the contraction angle, throat diameter, and diffusion angle were 34.5°, 15 mm, and 12.0°, respectively. The experimental results demonstrated that the application precisions of the optimised Venturi ejector were 99.23%, 98.46%, and 98.56% at application rates of 15, 20, and 25 g/s, respectively. The results provide a theoretical reference for the structural optimisation of the Venturi ejector and operational performance evaluation of the pneumatic conveying system for dazomet particles.

Optimisation of the Mechanical Properties and Mix Proportion of Multiscale-Fibre-Reinforced Engineered Cementitious Composites.

Engineered cementitious composites (ECCs) are cement-based composite materials with strain-hardening and multiple-cracking characteristics. ECCs have multiscale defects, including nanoscale hydrated silicate gels, micron-scale capillary pores, and millimetre-scale cracks. By using millimetre-scale polyethylene (PE) fibres, microscale calcium carbonate whiskers (CWs), and nanoscale carbon nanotubes (CNTs) as exo-doped fibres, a multiscale enhancement system was formed, and the effects of multiscale fibres on the mechanical properties of ECCs were tested. The Box-Behnken experimental design method, which is a response surface methodology, was used to construct a quadratic polynomial regression equation to optimise ECC design and provide an optimisation of ECC mix proportions. The results of this study showed that a multiscale reinforcement system consisting of PE fibres, CWs, and CNTs enhanced the mechanical properties of ECCs. CWs had the greatest effect on the compressive strengths of highly ductile-fibre-reinforced cementitious composites, followed by CNTs and PE fibres. PE fibres had the greatest effect on the flexural and tensile strengths of high-ductility fibre-reinforced cementitious composites, followed by CWs and CNTs. The final optimisation results showed that when the ECC matrix was doped with 1.55% PE fibres, 2.17% CWs, and 0.154% CNTs, the compressive strength, flexural strength, and tensile strength of the matrix were optimal.

Box-Behnken modeling and optimization of visible-light photocatalytic removal of methylene blue by ZnO-BiFeO3 composite.

Box-Behnken experimental design was utilized to model and optimize the photocatalytic removal of methylene blue (MB) using ZnO-BiFeO3 composite under visible light (LED). Three catalysts with different ZnO:BiFeO3 molar ratios (2:1, 1:2, and 1:1) were synthesized successfully using the hydrothermal method. The structural, morphological, and optical properties of the synthesized photocatalysts were analyzed by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), Fourier Transform Infrared Spectra (FT-IR), Ultraviolet Visible Spectrometer (UV-vis), Transmission Electron Microscopy(TEM), High-Resolution Transmission Electron Microscopy (HR-TEM), and Photoluminescence (PL) Spectrophotometry. FESEM showed the relatively uniform distribution of BiFeO3 crystalline particles on ZnO ones. UV-vis analysis showed that the photocatalytic performance of pure ZnO and BiFeO3 under visible light irradiation is weak, while ZnO-BiFeO3 with a 2:1 molar ratio composite with a bandgap of about 2.37eV showed high performance. This improved photocatalytic activity may be due to the heterogeneous synergistic effect of the p-n junction. In order to optimize the experimental conditions, four factors of initial MB concentration (5 to 20mg/L), pH (3 to 12), catalyst dosage (0.5 to 1.25mg/L), and light intensity (4 to 18 W) were selected as independent input variables. Box-Behnken experimental design method (BBD) suggested a quadratic polynomial equation to fit the experimental data. The results of the analysis of variance (ANOVA) confirmed the goodness of fit for the suggested model (predicted- and adjusted-R2 0.99). The optimum conditions for maximizing the photocatalytic MB degradation were found to be an initial MB concentration of 11mg/L, pH of 11.7, catalyst dosage of 0.716mg/L, and light intensity of 11.4 W. Under the optimum conditions, the highest photocatalytic MB degradation of 62.9% was obtained, which is in reasonable agreement with the predicted value of 69%.

A novel CO2-sensitive in situ deep eutectic solvent system: Efficient extraction of polyphenol phytochemicals

In the present study, monoethanolamine (MEA) was applied as a solvent for the extraction of polyphenols from lingonberry (Vaccinium vitis-idaea L.) pomace. In addition to solvent extraction an in situ DES could be formed with the secondary metabolites to obtain higher extraction yield. FT-IR, DSC, and TGA were used to validate MEA-based in situ DESs with reference compound. And the reusability of the solvent system still reached about 70.2% after the fifth cycles. The Box-Behnken experimental design method was used to determine the extraction efficiency under optimal conditions in practical applications, and the highest extraction yields of polyphenols increased 1.06–1.21 folds higher than that of traditional solvents. In addition, the extraction mechanism was studied using density functional theory. In summary, this study proposed a green and sustainable strategy to replace traditional solvents for targeted extraction of polyphenols from plants.

Box-Behnken Response Surface Method to Optimize Amine Liquid Purification Process Based on Ion Exchange

In the process of recycling MDEA (N-methyldiethanolamine) solution in a terminal decarburization system of CNOOC, the quality of MDEA solution was deteriorated due to the generation and accumulation of impurities such as solid suspended solids and heat stable salts, which led to blockage and unstable operation of pipeline equipment in the decarburization system, thus affecting the CO₂ removal effect of the solution, the Box-Behnken effect surface method was used to design the three main factors of the ion exchange-based amine purification process: the continuous adsorption time of the amine solution, the resin regeneration temperature and the resin regeneration time. Taking the conductivity of the MDEA solution after purification as the response function, a corresponding mathematical model was established to optimize the test method, and the correlation coefficient R² (R²=0.9418) of the regression equation obtained was greater than 0.9, indicating that the predicted value had a high correlation with the experimental value, and the test method was optimized accordingly. The best test conditions obtained were: the continuous adsorption time of amine solution was 50 min, the resin regeneration temperature was 40°C, and the resin regeneration time was 30 min. Under this condition, the conductivity of the purified MDEA solution was 1.56 ms/cm, and the salt content was 0.8%. The experiment was repeated 3 times according to this method, and the salt content of the MDEA solution after purification was ≯0.8%, which met the technological requirements. The Box-Behnken experimental design method was feasible for amine solution purification process optimization screening based on ion exchange, and the predicted value of the mathematical model was consistent with the experimental observation value.

Box-Behnken experimental design method application in pretreatment of olive oil mill wastewater by ultrafiltration

Box-Behnken experimental design method application in pretreatment of olive oil mill wastewater by ultrafiltration

Optimization of the Cutting Parameters Affecting the Turning of AISI 52100 Bearing Steel Using the Box-Behnken Experimental Design Method

In this study, we aimed to optimize the cutting parameters that affect the minimum temperature and power consumption in the turning of AISI 52100 bearing steel. For this, the Box-Behnken experimental design method, which was used for the lowest number of experiments in the experimental systems created using the response surface method (RSM), was used. The cutting parameters affecting the turning of the AISI 52100 bearing steel were determined as the cutting speed, depth of cut, and feed rate based on a literature research. The temperature and power consumption values were obtained via analyses according to the experimental design method determined by the finite element analysis (FEM) method. The results obtained were analyzed in Design Expert 13 software. According to the analysis results, the parameter values were determined for the minimum temperature and power consumption. The temperature and power consumption variables were affected by all three parameters, namely the cutting speed, depth of cut, and feed rate. For the minimum temperature and power consumption, a cutting speed of 162.427 m/min, depth of cut of 1.395 mm, and feed rate of 0.247 mm/rev, as well as the feed rate parameters, affected both the temperature and power consumption the most. In addition, it was determined that the cutting speed parameter had the least effect on both the temperature and power consumption variables. In addition, validation experiments were carried out in a real experimental environment with optimum values for the cutting parameters. The results showed that the output values obtained within the limits of the study with the obtained equation were quite close (3.3% error for temperature, 6.6% error for power consumption) to the real experimental outputs.

Design and Experiment with a Double-Roller Sweet Potato Vine Harvester

The yield of sweet potato vines is large, making it a good source of food. However, it is difficult to harvest sweet potato vines due to creeping and intertwining. Therefore, according to the domestic sweet potato planting model, this paper designed a double roll sweet potato vine harvester which can complete the operations of vine picking, vine killing, conveying and header harvesting at one time. The machine adopts the process of front roll vine picking, rear roll vine killing and rod bar lifting. The key components of the vine picking device, vine killing device and lifting device were designed and calculated. A numerical simulation test of the vine harvesting process was carried out by using the discrete element numerical simulation method. It was determined that the length of the vine picking rod from the outside to the inside is 175 mm, 150 mm and 105 mm, respectively, and the inclination angle of the end is 160°. There are six vine killing knives on each vine killing knife plate. The inclination of the lifting device is 50°and the conveying speed is 3 m/s. Using the box Behnken experimental design method, taking the vine picking roller speed, vine killing roller speed and ground clearance as the experimental factors, and taking the sweet potato vine harvest rate, stubble height and potato injury rate as the evaluation indexes, a quadratic regression orthogonal test was carried out, the effects of various factors on the evaluation indexes were analyzed, and the experimental factors were optimized and verified. The experimental results showed that the optimal parameter combination is as follows: the rotation speed of vine picking roller should be 716 r/min, the rotation speed of vine killing roller should be 1960 r/min and the ground clearance should be 16 mm. With these parameters, the harvest rate of sweet potato vines is 93.1%, the stubble height is 29.5 mm and the potato injury rate is 0.174%. As such, the harvester meets the requirements for the mechanized harvesting of sweet potato vines and is of great significance as a light and simplified product for the sweet potato industry.

基于CFD-DEM耦合的热风茶叶炒制机优化与试验

A drum-type hot air tea roasting machine was designed to improve the quality of the roasted tea. The basic structure and working principle of the machine were studied theoretically and experimentally. The CFD-DEM coupled method and the Box-Behnken experimental design method were introduced to analyse the influence of the shape of the anti-skid bars and working rotating speed on the tea-roasting quality. The optimum combination of the working parameters with the height of the anti-skid bar is 30 cm, the figure of the anti-skid bar is 6, the rotating speed of the roller is 15 r/min, the broken-tea ratio is 2.15%, and the tea’s sensory appraisal index is 89.32. The comprehensive performance index was better.

Degradation behavior of soybean straw reinforced PLA composites in different soil conditions

Soybean straw reinforced Polylactic acid (PLA) composites were prepared by extrusion injection molding, the Box–Behnken experimental design method was used to obtain the optimal molding parameters, and the soil degradation behavior of composites was studied. Soil burial test was lasted 63 days, these composites were degraded in loam, clay and sand conditions, respectively. The weight loss rate, mechanical properties, fourier transform infrared spectroscopy, thermos-gravimetric and surface micromorphology were analyzed. After 63 days of soil burial test, the increased weight loss rate and the decreased mechanical properties indicated the weak interfacial adhesion, the change of infrared absorption peak illustrated that the degradation degree of fiber and matrix, and the appearance of voids and cracks showed the poor interfacial bonding quality. It is indicated that loam and clay conditions had a deeper influence on the degradation behavior of soybean straw/PLA composites than sand conditions.

Experimental Study on the Optimization of Coal-Based Solid Waste Filling Slurry Ratio Based on the Response Surface Method.

The large production and low comprehensive utilization rate of solid waste from coal power base affects the efficient and coordinated development of regional resources and the ecological environment. In order to promote utilization of solid waste from coal power base, coal gangue, fly ash, and gasification slag are mixed as raw materials to prepare filling materials, and a study on the evolution law of the mechanical properties of coal-based solid waste filling body is systematically carried out. After clarifying the physical and chemical properties of the filling materials, the Box–Behnken experimental design method was used to study the effects of slurry mass fraction, coal gangue, fly ash, and gasification slag on the strength of the filling body based on the response surface-satisfaction function coupling theory. Furthermore, a multivariate nonlinear regression model was constructed for the strength of the filling body at different maintenance ages. Based on the analysis of variance (ANOVA) and the response surface function, the impact mechanism of influencing factors and their interaction on the strength of filler were revealed. The results show that the strength of the filler is affected by single factors and interactions between factors. The interaction of slurry mass fraction and gangue dosing has a significant effect on the strength of the filler in the early stage; the interaction of fly ash and gangue dosing has a significant effect on the strength of the filler in the middle stage; the interaction of slurry mass fraction and gasification slag dosing has a significant effect on the strength of the filler in the final stage. The mixed filling materials significantly affect the strength of the filler as the maintenance time is extended. The mixed filling materials are extensively interlaced with the hydration products, calcium alumina, and calcium silicate hydrate (C-S-H) gel, forming a stable three-dimensional spatial support system as the maintenance time increases. The best ratio to meet the requirements of mine filling slurry pipeline transportation and filling body strength was selected using the regression model and the proposed economic function of filling material.

Green synthesis of SiNH2@FeNP nanocomposite using and removal of methylene blue from aqueous solution: experimental design approach

ABSTRACT Within the scope of this study, the removal of methylene blue (MB) dye from aqueous solution with SiNH2@FeNP nanocomposite, which was synthesised by green synthesis method using liquorice root (Glycyrrhiza Glabra) extract, was investigated by applying Box-Behnken experimental design method. With this newly synthesised material, solution pH value, adsorbent dosage and initial dye concentration parameters affecting the adsorption process in methylene blue removal from aqueous solutions were investigated. FTIR, SEM, BET and XRD techniques were applied to characterise the structure of the obtained SiNH2@FeNP nanocomposite. According to the data obtained from the experimental design results, in order to obtain approximately 87% methylene blue dye removal efficiency, pH, initial methylene blue concentration and adsorbent dosage values should be kept constant at 8.8, 35.8 and 3.38 g L−1, respectively. Meanwhile, to achieve an MB adsorption of 22 mg g−1, the initial adsorbent dose and pH should be kept at 0.5 g l−1 and 10, respectively. SiNH2@FeNP nanocomposite produced by the green synthesis method is an environmentally friendly and effective adsorbent.

Analysis of Influencing Factors and Operation Quality Evaluation Strategy of Straw Crushing and Scattering System

First, through a single factor test, it was determined that the conveying and feeding speed range was 0.9~1.5 m/s, the rotating speed range of straw chopper shaft was 1900~2300 r/min, and the moisture content of straw was 26~34%. Then the Box–Behnken experimental design method was adopted, with conveying and feeding speed, cutter shaft rotation speed, and straw moisture content as influencing factors; small and stable specific power consumption and maximum coverage uniformity are taken as evaluation indexes. The influence rules of various factors on operation indexes were analyzed, and response surface analysis was carried out. Further, the optimization function in Design-Expert12.0 was used to determine the optimal parameter combination as follows: Conveying and feeding speed of 0.8 m/s, rotating speed of cutter shaft of 2059.9 r/min, moisture content of straw of 30.7%, corresponding specific power consumption and coverage uniformity of 1163 J/s2 and 99.1%, respectively. Finally, the seeding system was mounted behind the straw crushing and scattering system for a field verification test. The results showed that when the crushing and scattering system of the whole machine operates with the design parameters, the specific power consumption was 1260 J/s2, the uniformity of straw coverage was 94.7%, and the error with the experimental value was less than 5%. The effect was better than the standard requirement. The test realized the crushing and uniform coverage of high-quality straw residues after rice harvest, which proved the scientific and reliable test-bed of the crushing and scattering system.