Levulinic acid（LA） has been identified as a promising green,biomass derived platform chemical.Response surface analysis（RSA） with a four-factor-five-level central composite design（CCD） was applied to optimize th...Levulinic acid（LA） has been identified as a promising green,biomass derived platform chemical.Response surface analysis（RSA） with a four-factor-five-level central composite design（CCD） was applied to optimize the hydrolysis conditions for the conversion of bamboo（Phyllostachys Praecox f.preveynalis） shoot shell（BSS） to LA catalyzed with ionic liquid [C4mim]HSO4.The effects of four main reaction parameters including temperature,time,C[C4mim]HSO4（initial [C4mim]HSO4 concentration） and XBSS（initial BSS intake） on the hydrolysis reaction for yield of LA were analyzed.A quadratic equation model for yield of LA was established and fitted to the data with an R2 of 0.9868,and effects of main factors and their corresponding relationships were obtained with RSA.Model validation and results of CCD showed good correspondence between actual and predicted values.The analysis of variance（ANOVA） of the results indicated that the yield of LA in the range studied was significantly（P＆lt;0.05） affected by the four factors.The optimized reaction conditions were as follows：temperature of 145 ℃,time of 103.8 min,C[C4mim]HSO4 of 0.9 mol.L-1 and XBSS of 2.04%（by mass）,respectively.A high yield [（71±0.41）%（by mol）,triplicate experiment] was obtained at the optimum conditions of temperature of 145 ℃,time of 104 min,C[C4mim]HSO4 of 0.9 mol.L-1 and XBSS of 2%（by mass）,which obtained from the real experiments,concurred with the model prediction [73.8%（by mol） based on available C6 sugars in BSS or 17.9%（by mass） based on the mass of BSS],indicating that the model was adequate for the hydrolysis process.展开更多
Background:Polygonati cyrtonema Hua(PC)has many pharmacological effects such as immune regulation,hypoglycemic and lipid-lowering,anti-oxidation and anti-tumor.Oligosaccharide is one of the main active components of P...Background:Polygonati cyrtonema Hua(PC)has many pharmacological effects such as immune regulation,hypoglycemic and lipid-lowering,anti-oxidation and anti-tumor.Oligosaccharide is one of the main active components of PC.At present,the research on Polygonatum cyrtonema oligosaccharides(PCOS)is not deep,and there is a lack of systematic research on the optimization of extraction process of pcos and the change of pcos and Polygonatum cyrtonema polysaccharide content before and after wine steaming.Methods:The optimum extraction process of oligosaccharides from PC was optimized,and the content of oligosaccharides before and after wine steaming of PC was investigated.The single factor experiment was carried out with the ratio of liquid to material,extraction temperature and extraction time as the investigation factors.The extraction process of PCOS was optimized by Box Behnken design-response surface methodology,and the changes of total oligosaccharides and total polysaccharides before and after wine steaming were studied.Results:The optimal extraction process for the PCOS was 32:1 mL/g,85℃,and 1.5 h.The total PCOS decreased slightly after steaming,but the percentage of the total sugar increased.Conclusion:The extraction process of PCOS optimized by response surface method is reasonable and feasible.The changes of total oligosaccharides and total polysaccharides during the steaming process of PC can reveal the processing mechanism of PC to a certain extent,and provide scientific basis and technical support for better in-depth excavation and development and utilization of PCOS.展开更多
[Objectives]Polysaccharide was extracted from Lactarius deliciosus by ultrasonic-assisted method to improve polysaccharide yield.[Methods]Five variables including extraction temperature,extraction time,ultrasonic powe...[Objectives]Polysaccharide was extracted from Lactarius deliciosus by ultrasonic-assisted method to improve polysaccharide yield.[Methods]Five variables including extraction temperature,extraction time,ultrasonic power,ultrasonic time and material-to-liquid ratio were selected for single factor experiments.The extraction process of L.deliciosus polysaccharide was optimized by response surface analysis,and its antioxidant activity was evaluated by measuring its total reduction ability and DPPH free radical scavenging capacity.[Results]The optimal extraction conditions were determined as follows:material-to-liquid ratio 1:35 g:ml,ultrasonic power 462 W,ultrasonic time 10 min,extraction time 110 min and extraction temperature 90℃.Under these conditions,the extraction rate of polysaccharide was(10.83±0.03)%.The antioxidant test results showed that when the mass concentration of L.deliciosus polysaccharide was 0.5 mg/ml,its absorbance and DPPH free radical scavenging rate reached their maximum values,which were 3.274%and 41.27%,respectively.The L.deliciosus polysaccharide had good antioxidant properties.[Conclusions]This study provides a theoretical basis for further development and utilization of L.deliciosus polysaccharide in the future.展开更多
To develop a sound ozone（O_3） pollution control strategy,it is important to well understand and characterize the source contribution due to the complex chemical and physical formation processes of O_3.Using the ＂Sh...To develop a sound ozone（O_3） pollution control strategy,it is important to well understand and characterize the source contribution due to the complex chemical and physical formation processes of O_3.Using the ＂Shunde＂ city as a pilot summer case study,we apply an innovative response surface modeling（RSM） methodology based on the Community Multi-Scale Air Quality（CMAQ） modeling simulations to identify the O_3 regime and provide dynamic analysis of the precursor contributions to effectively assess the O_3 impacts of volatile organic compound（VOC） control strategy.Our results show that Shunde is a typical VOC-limited urban O_3 polluted city.The ＂Jiangmen＂ city,as the main upper wind area during July 2014,its VOCs and nitrogen oxides（NO_x） emissions make up the largest contribution（9.06%）.On the contrary,the contribution from local（Shunde） emission is lowest（6.35%） among the seven neighbor regions.The local VOCs industrial source emission has the largest contribution comparing to other precursor emission sectors in Shunde.The results of dynamic source contribution analysis further show that the local NO_x control could slightly increase the ground O_3 under low（10.00%） and medium（40.00%）reduction ratios,while it could start to turn positive to decrease ground O_3 under the high NO_x abatement ratio（75.00%）.The real-time assessment of O_3 impacts from VOCs control strategies in Pearl River Delta（PRD） shows that the joint regional VOCs emission control policy will effectively reduce the ground O_3 concentration in Shunde.展开更多
The water vapor permeability （WVP） of films is important when developing pharmaceutical applications. Films are frequently used as coatings, and as such directly influence the quality of the medicine. The optimizati...The water vapor permeability （WVP） of films is important when developing pharmaceutical applications. Films are frequently used as coatings, and as such directly influence the quality of the medicine. The optimization of processing conditions for sodium alginate films was investigated using response surface methodology. Single-factor tests and Box-Behnken experimental design were employed. WVP was selected as the response variable, and the operating parameters for the single-factor tests were sodium alginate concentration, carboxymethyl cellulose （CMC） concentration and CaClz solution immersion time. The coefficient of determination （R2） was 0.97, indicating statistical significance. A minimal WVP of 0.389 8 g-mm/（m^2.h.kPa） was achieved under the optimum conditions. These were found to be a sodium alginate concentration, CMC concentration and CaCl2 solution immersion time at 8.04%, 0.13%, and 12 min, respectively. This provides a reference for potential applications in manufacturing film-coated hard capsule shells.展开更多
To reasonably design the blade-tip radial running clearance(BTRRC) of high pressure turbine and improve the performance and reliability of gas turbine, the multi-object multi-discipline reliability sensitivity analysi...To reasonably design the blade-tip radial running clearance(BTRRC) of high pressure turbine and improve the performance and reliability of gas turbine, the multi-object multi-discipline reliability sensitivity analysis of BTRRC was accomplished from a probabilistic prospective by considering nonlinear material attributes and dynamic loads. Firstly, multiply response surface model(MRSM) was proposed and the mathematical model of this method was established based on quadratic function. Secondly, the BTRRC was decomposed into three sub-components(turbine disk, blade and casing), and then the single response surface functions(SRSFs) of three structures were built in line with the basic idea of MRSM. Thirdly, the response surface function(MRSM) of BTRRC was reshaped by coordinating SRSFs. From the analysis, it is acquired to probabilistic distribution characteristics of input-output variables, failure probabilities of blade-tip clearance under different static blade-tip clearances δ and major factors impacting BTRRC. Considering the reliability and efficiency of gas turbine, δ=1.87 mm is an optimally acceptable option for rational BTRRC. Through the comparison of three analysis methods(Monte Carlo method, traditional response surface method and MRSM), the results show that MRSM has higher accuracy and higher efficiency in reliability sensitivity analysis of BTRRC. These strengths are likely to become more prominent with the increasing times of simulations. The present study offers an effective and promising approach for reliability sensitivity analysis and optimal design of complex dynamic assembly relationship.展开更多
OBJECTIVE:To optimize the vinegar-steaming process of Wuweizi(Fructus Schisandrae Chinensis)using the response surface method(RSM)based on the Box-Behnken design.METHODS:A regression model was constructed with the res...OBJECTIVE:To optimize the vinegar-steaming process of Wuweizi(Fructus Schisandrae Chinensis)using the response surface method(RSM)based on the Box-Behnken design.METHODS:A regression model was constructed with the response variables,the content of Deoxyschizandrin,and the three explanatory factors:length of steaming time,the quantity of vinegar and length of moistening time to evaluate the effects on the processing of Wuweizi(Fructus SchisandraeChinensis).RESULTS:There was a linear relationship between the content of Deoxyschizandrin and the three explanatory factors.When the steaming time was5.49 h,with 2.365 g of vinegar added and a moistening time of 4.13 h,the content of Deoxyschizandrin reached the maximum predicted value of0.1076%,and under the conditions the average content of Deoxyschizandrin was 0.1058%.CONCLUSION:The correlation coefficient of thenonlinear mathematical model was relatively high and the model matched the data well,potentially providing a method for the study of the steaming process.展开更多
This study examined the relationship between leader-employee calling congruence on employees’voice behaviour.Participants were 173 leader-employee dyads from the Chinese service industry.They completed online surveys...This study examined the relationship between leader-employee calling congruence on employees’voice behaviour.Participants were 173 leader-employee dyads from the Chinese service industry.They completed online surveys on calling,perceived insider status,and voice behaviour.Results from polynomial regression and response surface analysis showed that employees perceived insider status to be weaker with the low leader-low subordinate calling congruence,and stronger with high leader and high subordinate calling congruence.Employees perceived insider status is stronger in low leader and high subordinate calling incongruence compared with high leader and low subordinate calling incongruence.Perceived insider status plays a mediating role among calling congruence and voice behaviour.This study’sfindings suggest pathways of calling congruence on voice behaviour,which are important for promoting employee voice behaviour and guiding organisational recruitment in the workplace.展开更多
Disposing of coal gangue and fly-ash on the surface is a risky method with tremendous potential catastrophic consequences for the environment.Backfill mining is a promising practice for turning those hazardous wastes ...Disposing of coal gangue and fly-ash on the surface is a risky method with tremendous potential catastrophic consequences for the environment.Backfill mining is a promising practice for turning those hazardous wastes into functional backfill materi-als.Unfortunately,how to efficiently deliver the slurry to the desired places remains under-researched.To address this issue,the computational fluid dynamics software Fluent was used in the current study in addition to a laboratory rheological test to simulate the impact of various parameters on the evolution of pressure at a particular section of the pipeline.Furthermore,the response surface method was employed to investigate how the various components and their corresponding influencing weights interact to affect the pressure drop.This study demonstrates that the pressure drop of the slurry is highly influenced by slurry concentration,speed,and pipe diameter.While conveying speed is the main component in the bend section,pipe diameter takes over in the horizontal and vertical pipe sections.展开更多
In the present study,three layers of aluminum(Al)and a single layer of copper(Cu)were joined by resistance rolling welding(RRW)and the impact of welding velocity on microstructure,mechanical property and electrical pr...In the present study,three layers of aluminum(Al)and a single layer of copper(Cu)were joined by resistance rolling welding(RRW)and the impact of welding velocity on microstructure,mechanical property and electrical property was investigated.The results showed that the welding velocity was identified as the most significant parameter.With decreasing the welding velocity from 11 mm/s to 1 mm/s,the mechanical property of the joints initially showed an increase,reaching a maximum coach-peel peak load of 185.25 N,due to the larger well bonded region,then decreased owing to the high-temperature softening of the base metal.The elec-trical resistance of the joint demonstrated a consistent varying,characterized by an initial decrease owing to the larger completely bonded region and then increased with the decreasing welding velocity due to the excessive generation of Al2Cu with high electrical resistance.A cooling system was thus utilized to reduce the welding temperature to relieve the high-temperature softening,that suc-cessfully improved the welding quality of the joint by an 11.5%increase in the coach-peel peak load.展开更多
In order to optimize the microwave-assisted extraction technology of polyphenols from Loropetalum chinense （R. Br.） Oliv., the effects of microwave power, ethanol concentration, solid to liquid ratio and extraction ...In order to optimize the microwave-assisted extraction technology of polyphenols from Loropetalum chinense （R. Br.） Oliv., the effects of microwave power, ethanol concentration, solid to liquid ratio and extraction time on polyphenols extraction rate were investigated. On the basis of single-factor test, a four-factor and three-level orthogonal test was designed by response surface method to establish a mathematical model between the response value and various factors. The results showed that the intensity of effect of different influencing factor on polyphenols ex- traction rate ranked as microwave power＇s〉solid to liquid ratio＇s〉extraction time＇s〉 ethanol concentration＇s. The optimum microwave-assisted extraction conditions for polyphenols from L. chinense were as follows： extraction power 254 W, ethanol concentration 60%, extraction time 12.5 rain and solid to liquid ratio 1：17. Under the optimum extraction conditions, the extraction rate of polyphenols from L. chinense was 19.17%.展开更多
Polymer electrolyte membrane fuel cells(PEMFCs)are considered a promising alternative to internal combustion engines in the automotive sector.Their commercialization is mainly hindered due to the cost and effectivenes...Polymer electrolyte membrane fuel cells(PEMFCs)are considered a promising alternative to internal combustion engines in the automotive sector.Their commercialization is mainly hindered due to the cost and effectiveness of using platinum(Pt)in them.The cathode catalyst layer(CL)is considered a core component in PEMFCs,and its composition often considerably affects the cell performance(V_(cell))also PEMFC fabrication and production(C_(stack))costs.In this study,a data-driven multi-objective optimization analysis is conducted to effectively evaluate the effects of various cathode CL compositions on Vcelland Cstack.Four essential cathode CL parameters,i.e.,platinum loading(L_(Pt)),weight ratio of ionomer to carbon(wt_(I/C)),weight ratio of Pt to carbon(wt_(Pt/c)),and porosity of cathode CL(ε_(cCL)),are considered as the design variables.The simulation results of a three-dimensional,multi-scale,two-phase comprehensive PEMFC model are used to train and test two famous surrogates:multi-layer perceptron(MLP)and response surface analysis(RSA).Their accuracies are verified using root mean square error and adjusted R^(2).MLP which outperforms RSA in terms of prediction capability is then linked to a multi-objective non-dominated sorting genetic algorithmⅡ.Compared to a typical PEMFC stack,the results of the optimal study show that the single-cell voltage,Vcellis improved by 28 m V for the same stack price and the stack cost evaluated through the U.S department of energy cost model is reduced by$5.86/k W for the same stack performance.展开更多
Fabrication of the Mg–9Al–1Zn–0.5Mn alloy with excellent mechanical performance using selective laser melting(SLM)technology is quite difficult owing to the poor weldability and low boiling point.To address these ch...Fabrication of the Mg–9Al–1Zn–0.5Mn alloy with excellent mechanical performance using selective laser melting(SLM)technology is quite difficult owing to the poor weldability and low boiling point.To address these challenges and seek the optimal processing parameters,response surface methodology was systematically utilized to determine the appropriate SLM parameter combinations.Mg–9Al–1Zn–0.5Mn sample with high relative density(99.5±0.28%)and favorable mechanical properties(microhardness=95.6±5.28 HV_(0.1),UTS=370.2 MPa,and At=10.4%)was achieved using optimized SLM parameters(P=120 W,v=500 mm/s,and h=45μm).Sample is dominated by a random texture and microstructure is primarily constituted by quantities offine equiaxed grains(α-Mg phase),a small amount ofβ-Al_(12)Mg_(17) structures(4.96 vol%,including spherical:[2110]_(α)//[111]_(β)and long lath-like:[2110]_(α)//[115]_(β)or[1011]_(α)//[321]_(β)),and some short rod-shaped Al8Mn5 nanoparticles.Benefiting from grain boundary strengthening,solid solution strengthening,and precipitation hardening of various nanoparticles(β-Al12Mg17 and Al8Mn5),high-performance Mg–9Al–1Zn–0.5Mn alloy biomedical implants can be fabricated.Precipitation hardening dominates the strengthening mechanism of the SLM Mg–9Al–1Zn–0.5Mn alloy.展开更多
Amyloid fibers are now considered as one of the possible therapeutic targets of neurodegenerative diseases due to their unique physicochemical properties and toxicity. To efficiently trace in real time how the drug in...Amyloid fibers are now considered as one of the possible therapeutic targets of neurodegenerative diseases due to their unique physicochemical properties and toxicity. To efficiently trace in real time how the drug inhibits protein amyloid fibrosis, it is necessary to study the conditions for rapid amyloid fibrosis. Insulin is selected as the model protein in vitro to explore the process of amyloid formation. The effects of the molar concentration of NaCl, pH and reaction temperature in the single-factor experiment are discussed and the response surface analysis is carried out. Amyloid fibrosis is labeled by Thioflavin-T(ThT). The optimal molar concentration of NaCl, pH and reaction temperature for insulin rapid amyloid fibrosis are 50.0 mmol/L, 2.02 and 54℃, respectively. With the addition of 0.1 mmol/L phenol, the half-time of insulin amyloid fibrosis is shortened from 5.4 h to 1.7 h. The insulin rapid amyloid fibrosis system provides a new approach for screening the protein amyloid fibrosis inhibitors.展开更多
The inhibition effects and mechanisms of chlorinated methane and acetylene on methanogenesis in the anaerobic digestion process of the biodegradable wastes were investigated.It was found that both chloroform and acety...The inhibition effects and mechanisms of chlorinated methane and acetylene on methanogenesis in the anaerobic digestion process of the biodegradable wastes were investigated.It was found that both chloroform and acetylene could effectively inhibit methanogens while the biodegradability of the wastes was not affected.Acetylene inhibited the activity of methanogens,while chloroform inhibited metabolic process of methanogenesis.A central composite design（CCD） and response surface regression analysis（RSREG） were employed to determine the optimum conditions and interaction effects of chloroform and acetylene in terms of inhibition effciency,production of volatile fatty acids（VAF） and molar ratio of propionic acid to acetic acid.Chloroform had significant effect on enhancing the production of VFA（F = 121.3;p 〈 0.01）,and acetylene promoted the inhibition effciency（F = 99.15;p 〈 0.05） more effectively than chloroform（F = 9.72;p 〉 0.05）.In addition,a maximum molar ratio of propionic acid to acetic acid of 1.208 was estimated under the optimum conditions of chloroform concentration of 9.05 mg/kg and acetylene concentration of 3.6×10^-3（V/V）.Hence,methanogens in the wastes can be inhibited while the stabilization process of the biodegradable wastes can still work well,as propionic acid generated during the inhibition process could hardly be utilized by methanogens.展开更多
The effect of soil nutrient content on fruit yield and fruit quality is very important.To explore the effect of soil nutrients on apple quality we investigated 200 fruit samples from 40 orchards in Feng County,Jiangsu...The effect of soil nutrient content on fruit yield and fruit quality is very important.To explore the effect of soil nutrients on apple quality we investigated 200 fruit samples from 40 orchards in Feng County,Jiangsu Province.Soil mineral elements and fruit quality were measured.The effect of soil nutrient content on fruit quality was analyzed by artificial neural network(ANN)model.The results showed that the prediction accuracy was highest(R2=0.851,0.847,0.885,0.678 and 0.746)in mass per fruit(MPF),hardness(HB),soluble solids concentrations(SSC),titratable acid concentration(TA)and solid-acid ratio(SSC/TA),respectively.The sensitivity analysis of the prediction model showed that soil available P,K,Ca and Mg contents had the greatest impact on the quality of apple fruit.Response surface method(RSM)was performed to determine the optimum range of the available P,K,Ca,and Mg contents in orchards In Feng County,which were 10∼20 mg⋅kg^(−1),170∼200 mg⋅kg^(−1),1000∼1500 mg⋅kg^(−1),and 80∼200 mg⋅kg^(−1),respectively.The research also concluded that improving the content of available P and available Ca in orchard soil was crucial to improve apple fruit quality in Feng County,Jiangsu Province.展开更多
As important factors in discrete elements,the physical parameters of watermelon seeds play a pivotal role in discrete element method.To obtain the discrete element parameters of watermelon seeds and improve the accura...As important factors in discrete elements,the physical parameters of watermelon seeds play a pivotal role in discrete element method.To obtain the discrete element parameters of watermelon seeds and improve the accuracy of the discrete element model,through a combination of actual and simulation tests,this research has calibrated the seeds’physical and contact parameters with the seed metering device.Employing the Plackett-Burman experiment,this study has identified three critical factors affecting the stacking angle:the static and rolling friction coefficients between seeds,and the collision recovery coefficient between seeds and plexiglass.Using the steepest-climbing design and Box-Behnken response surface analysis,this research has optimized these factors to values of 0.716,0.051,and 0.787,achieving a calibration error of just 2.60%.Verification with an air suction precision seed metering device confirmed the parameters’accuracy,with relative errors below 7.65%.The discrepancy between the simulation and actual test results,as measured by the qualified index error,is successfully reduced to below 4.38%.This study thus establishes a solid foundation for the structural optimization of air suction precision watermelon seed metering devices.展开更多
Maize picking is the main form of maize harvest in China.Maize picking loss accounts for a large proportion of the current maize harvest loss.An experimental study and a theoretical analysis were conducted to explore ...Maize picking is the main form of maize harvest in China.Maize picking loss accounts for a large proportion of the current maize harvest loss.An experimental study and a theoretical analysis were conducted to explore the influencing factors and rules of maize picking loss.First,the boundary conditions,established by analyzing the mechanism of maize picking,determined the influences of maize picking loss.Then,single-factor experiments and a central composite design(CCD)method were used to determine the influence of various factors and their interactions on maize picking loss.Finally,the models of kernel loss and ear loss were set up to determine the optimal parameter combination of maize picking harvest.Field experiment verification was conducted.The results indicated that the optimal parameters of the maize picking harvest were the rotational speed of pulling rollers of 1120 r/min,operating speed of 1.94 m/s,the inclination of the header of 18°and clearance between the picking plates of 30 mm.By establishing these optimal parameters,the kernel loss rate was 0.065%,and the ear loss rate was 0%.The obtained experimental results and regression models could be used to predict the performance of the maize picking harvest,guide the adjustment of header working parameters,and provide a theoretical basis for reducing the mechanical loss of maize harvesting.展开更多
Uniform crushed straw throwing and seed-sowing machines can achieve the processes of straw chopping,straw transport,sowing,fertilization,and straw mulching at the same time,which is widely used in many areas of China....Uniform crushed straw throwing and seed-sowing machines can achieve the processes of straw chopping,straw transport,sowing,fertilization,and straw mulching at the same time,which is widely used in many areas of China.Conveying device is one of the important components used to convey,elevate and throw straw.However,the problems of high power consumption and congestion affect the promotion of the machine.Therefore,the conveying device of uniform crushed straw throwing and seed-sowing machine was analyzed in order to determine its device operation mechanism.Kinematic and dynamic analyses of particles of crushed rice straw during lifting and dispersion are used to develop a flexible-body model of rod-shaped and agglomerate-shaped crushed straw and a coupling model including the mechanical structure of the device.By integrating computational fluid dynamics and the discrete element method,the gas-solid coupling theory in numerical simulations and motion analysis of crushed straw particles is used to determine how the flow field and motion characteristics affect the conveying performance.Besides,regression equations to describe the relationships between the factors and each assessment index were established by using the regression analysis and response surface analysis with the software Design-Expert.The effect of throwing blade speed X_(1),conveying volume of crushed straw X_(2),and pipeline diameter X_(3) on the throwing speed of crushed straw Y_(1) and specific power consumption Y2 were investigated.The highest throwing speed of crushed straw and lowest specific power consumption are the optimization goal.The results of optimization showed that the predict the best optimal parameters were 2000 r/min throwing blade rotational speed,1.4 kg/s conveying volume,and 220 mm pipeline diameter,the planter achieved a throwing speed of 12.2 m/s and specific power consumption of 9179 m^(2)/s^(2).And then a field test verification was conducted.The planter achieved a throwing speed 12.4 m/s and specific power consumption 9070 m^(2)/s^(2) while selecting the best optimal parameters.Thus,the optimal parameters can provide a high-performance operation and satisfy the actual operation requirements The results provide a theoretical basis and data support for seeding technology innovation and equipment optimization to ensure uniform crushed straw throwing in dense rice stubble fields.展开更多
The plasma-coupled electrocatalytic cascade technology with NO_x~-as intermediate product is a potential method to realize green ammonia synthesis.The matching of the formation rate and consumption rate of NO_(2)^(-)a...The plasma-coupled electrocatalytic cascade technology with NO_x~-as intermediate product is a potential method to realize green ammonia synthesis.The matching of the formation rate and consumption rate of NO_(2)^(-)as the main absorption product is an important prerequisite for the system to achieve stable operation.Therefore,this paper firstly emphasizes the importance of operating parameters on the cascade system based on the single factor experiment.Secondly,the empirical equation between electrocatalytic operating conditions and NO_(2)^(-)consumption rate was established by response surface analysis.Based on this equation,the electrocatalytic operating parameters were optimized to achieve the dynamic equilibrium between NO_(2)^(-)formation rate and consumption rate.Finally,the techno-economic assessment model was established to calculate the levelized cost of ammonia based on the cascade system,and the single-variable sensitivity analysis was performed to provide the clear guidance for cost reduction.展开更多
基金Supported by the National Natural Science Foundation of China（30940058,31170672）the Natural Science Foundation of Zhejiang Province of China（Y3110025）+1 种基金Key Laboratory for Physical Processing of Agricultural Products（JAPP2010-4）Key Laboratory of Exploitation and Preservation of Coastal Bio-resource（2010F30003）
文摘Levulinic acid（LA） has been identified as a promising green,biomass derived platform chemical.Response surface analysis（RSA） with a four-factor-five-level central composite design（CCD） was applied to optimize the hydrolysis conditions for the conversion of bamboo（Phyllostachys Praecox f.preveynalis） shoot shell（BSS） to LA catalyzed with ionic liquid [C4mim]HSO4.The effects of four main reaction parameters including temperature,time,C[C4mim]HSO4（initial [C4mim]HSO4 concentration） and XBSS（initial BSS intake） on the hydrolysis reaction for yield of LA were analyzed.A quadratic equation model for yield of LA was established and fitted to the data with an R2 of 0.9868,and effects of main factors and their corresponding relationships were obtained with RSA.Model validation and results of CCD showed good correspondence between actual and predicted values.The analysis of variance（ANOVA） of the results indicated that the yield of LA in the range studied was significantly（P＆lt;0.05） affected by the four factors.The optimized reaction conditions were as follows：temperature of 145 ℃,time of 103.8 min,C[C4mim]HSO4 of 0.9 mol.L-1 and XBSS of 2.04%（by mass）,respectively.A high yield [（71±0.41）%（by mol）,triplicate experiment] was obtained at the optimum conditions of temperature of 145 ℃,time of 104 min,C[C4mim]HSO4 of 0.9 mol.L-1 and XBSS of 2%（by mass）,which obtained from the real experiments,concurred with the model prediction [73.8%（by mol） based on available C6 sugars in BSS or 17.9%（by mass） based on the mass of BSS],indicating that the model was adequate for the hydrolysis process.
基金sponsored by National Key Research and Development Program of China(Grant No.2023YFC3504200)High Level Key Discipline Construction of Traditional Chinese Medicine Program(Grant No.zyyzdxk-2023272).
文摘Background:Polygonati cyrtonema Hua(PC)has many pharmacological effects such as immune regulation,hypoglycemic and lipid-lowering,anti-oxidation and anti-tumor.Oligosaccharide is one of the main active components of PC.At present,the research on Polygonatum cyrtonema oligosaccharides(PCOS)is not deep,and there is a lack of systematic research on the optimization of extraction process of pcos and the change of pcos and Polygonatum cyrtonema polysaccharide content before and after wine steaming.Methods:The optimum extraction process of oligosaccharides from PC was optimized,and the content of oligosaccharides before and after wine steaming of PC was investigated.The single factor experiment was carried out with the ratio of liquid to material,extraction temperature and extraction time as the investigation factors.The extraction process of PCOS was optimized by Box Behnken design-response surface methodology,and the changes of total oligosaccharides and total polysaccharides before and after wine steaming were studied.Results:The optimal extraction process for the PCOS was 32:1 mL/g,85℃,and 1.5 h.The total PCOS decreased slightly after steaming,but the percentage of the total sugar increased.Conclusion:The extraction process of PCOS optimized by response surface method is reasonable and feasible.The changes of total oligosaccharides and total polysaccharides during the steaming process of PC can reveal the processing mechanism of PC to a certain extent,and provide scientific basis and technical support for better in-depth excavation and development and utilization of PCOS.
基金Supported by High-level Cultivation Project of Huanggang Normal University(201816703).
文摘[Objectives]Polysaccharide was extracted from Lactarius deliciosus by ultrasonic-assisted method to improve polysaccharide yield.[Methods]Five variables including extraction temperature,extraction time,ultrasonic power,ultrasonic time and material-to-liquid ratio were selected for single factor experiments.The extraction process of L.deliciosus polysaccharide was optimized by response surface analysis,and its antioxidant activity was evaluated by measuring its total reduction ability and DPPH free radical scavenging capacity.[Results]The optimal extraction conditions were determined as follows:material-to-liquid ratio 1:35 g:ml,ultrasonic power 462 W,ultrasonic time 10 min,extraction time 110 min and extraction temperature 90℃.Under these conditions,the extraction rate of polysaccharide was(10.83±0.03)%.The antioxidant test results showed that when the mass concentration of L.deliciosus polysaccharide was 0.5 mg/ml,its absorbance and DPPH free radical scavenging rate reached their maximum values,which were 3.274%and 41.27%,respectively.The L.deliciosus polysaccharide had good antioxidant properties.[Conclusions]This study provides a theoretical basis for further development and utilization of L.deliciosus polysaccharide in the future.
基金Financial support for this work is provided by the Shunde Environment ProtectionTransportation and Urban Administration Bureau(no.0851-1361FS02CL51)+5 种基金the Guangdong Provincial Science and Technology Plan Projects(no.2014A050503019)Guangzhou Environmental Protection Bureau(no.x2hjB2150020)supported by the funding of State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complexthe project of Atmospheric Haze Collaboration Control Technology Design(no.XDB05030400)from Chinese Academy of Sciencesthe Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(U1501501)(the second phase)the Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal(no.b2152120)
文摘To develop a sound ozone（O_3） pollution control strategy,it is important to well understand and characterize the source contribution due to the complex chemical and physical formation processes of O_3.Using the ＂Shunde＂ city as a pilot summer case study,we apply an innovative response surface modeling（RSM） methodology based on the Community Multi-Scale Air Quality（CMAQ） modeling simulations to identify the O_3 regime and provide dynamic analysis of the precursor contributions to effectively assess the O_3 impacts of volatile organic compound（VOC） control strategy.Our results show that Shunde is a typical VOC-limited urban O_3 polluted city.The ＂Jiangmen＂ city,as the main upper wind area during July 2014,its VOCs and nitrogen oxides（NO_x） emissions make up the largest contribution（9.06%）.On the contrary,the contribution from local（Shunde） emission is lowest（6.35%） among the seven neighbor regions.The local VOCs industrial source emission has the largest contribution comparing to other precursor emission sectors in Shunde.The results of dynamic source contribution analysis further show that the local NO_x control could slightly increase the ground O_3 under low（10.00%） and medium（40.00%）reduction ratios,while it could start to turn positive to decrease ground O_3 under the high NO_x abatement ratio（75.00%）.The real-time assessment of O_3 impacts from VOCs control strategies in Pearl River Delta（PRD） shows that the joint regional VOCs emission control policy will effectively reduce the ground O_3 concentration in Shunde.
基金Supported by the Program for Transformation of Scientific and Technological Achievements of Jiangsu Province,China(No.BA2009088)
文摘The water vapor permeability （WVP） of films is important when developing pharmaceutical applications. Films are frequently used as coatings, and as such directly influence the quality of the medicine. The optimization of processing conditions for sodium alginate films was investigated using response surface methodology. Single-factor tests and Box-Behnken experimental design were employed. WVP was selected as the response variable, and the operating parameters for the single-factor tests were sodium alginate concentration, carboxymethyl cellulose （CMC） concentration and CaClz solution immersion time. The coefficient of determination （R2） was 0.97, indicating statistical significance. A minimal WVP of 0.389 8 g-mm/（m^2.h.kPa） was achieved under the optimum conditions. These were found to be a sodium alginate concentration, CMC concentration and CaCl2 solution immersion time at 8.04%, 0.13%, and 12 min, respectively. This provides a reference for potential applications in manufacturing film-coated hard capsule shells.
基金Projects(51175017,51245027)supported by the National Natural Science Foundation of China
文摘To reasonably design the blade-tip radial running clearance(BTRRC) of high pressure turbine and improve the performance and reliability of gas turbine, the multi-object multi-discipline reliability sensitivity analysis of BTRRC was accomplished from a probabilistic prospective by considering nonlinear material attributes and dynamic loads. Firstly, multiply response surface model(MRSM) was proposed and the mathematical model of this method was established based on quadratic function. Secondly, the BTRRC was decomposed into three sub-components(turbine disk, blade and casing), and then the single response surface functions(SRSFs) of three structures were built in line with the basic idea of MRSM. Thirdly, the response surface function(MRSM) of BTRRC was reshaped by coordinating SRSFs. From the analysis, it is acquired to probabilistic distribution characteristics of input-output variables, failure probabilities of blade-tip clearance under different static blade-tip clearances δ and major factors impacting BTRRC. Considering the reliability and efficiency of gas turbine, δ=1.87 mm is an optimally acceptable option for rational BTRRC. Through the comparison of three analysis methods(Monte Carlo method, traditional response surface method and MRSM), the results show that MRSM has higher accuracy and higher efficiency in reliability sensitivity analysis of BTRRC. These strengths are likely to become more prominent with the increasing times of simulations. The present study offers an effective and promising approach for reliability sensitivity analysis and optimal design of complex dynamic assembly relationship.
基金Supported by Scientific Research Foundation of Health Department of Shaanxi Province(2012D14),China
文摘OBJECTIVE:To optimize the vinegar-steaming process of Wuweizi(Fructus Schisandrae Chinensis)using the response surface method(RSM)based on the Box-Behnken design.METHODS:A regression model was constructed with the response variables,the content of Deoxyschizandrin,and the three explanatory factors:length of steaming time,the quantity of vinegar and length of moistening time to evaluate the effects on the processing of Wuweizi(Fructus SchisandraeChinensis).RESULTS:There was a linear relationship between the content of Deoxyschizandrin and the three explanatory factors.When the steaming time was5.49 h,with 2.365 g of vinegar added and a moistening time of 4.13 h,the content of Deoxyschizandrin reached the maximum predicted value of0.1076%,and under the conditions the average content of Deoxyschizandrin was 0.1058%.CONCLUSION:The correlation coefficient of thenonlinear mathematical model was relatively high and the model matched the data well,potentially providing a method for the study of the steaming process.
基金supported by the Major Research Project of Philosophy and Social Sciences in Universities of Henan Province(2025-JCZD-10)the Natural Science Foundation of Henan Province(242300421311).
文摘This study examined the relationship between leader-employee calling congruence on employees’voice behaviour.Participants were 173 leader-employee dyads from the Chinese service industry.They completed online surveys on calling,perceived insider status,and voice behaviour.Results from polynomial regression and response surface analysis showed that employees perceived insider status to be weaker with the low leader-low subordinate calling congruence,and stronger with high leader and high subordinate calling congruence.Employees perceived insider status is stronger in low leader and high subordinate calling incongruence compared with high leader and low subordinate calling incongruence.Perceived insider status plays a mediating role among calling congruence and voice behaviour.This study’sfindings suggest pathways of calling congruence on voice behaviour,which are important for promoting employee voice behaviour and guiding organisational recruitment in the workplace.
文摘Disposing of coal gangue and fly-ash on the surface is a risky method with tremendous potential catastrophic consequences for the environment.Backfill mining is a promising practice for turning those hazardous wastes into functional backfill materi-als.Unfortunately,how to efficiently deliver the slurry to the desired places remains under-researched.To address this issue,the computational fluid dynamics software Fluent was used in the current study in addition to a laboratory rheological test to simulate the impact of various parameters on the evolution of pressure at a particular section of the pipeline.Furthermore,the response surface method was employed to investigate how the various components and their corresponding influencing weights interact to affect the pressure drop.This study demonstrates that the pressure drop of the slurry is highly influenced by slurry concentration,speed,and pipe diameter.While conveying speed is the main component in the bend section,pipe diameter takes over in the horizontal and vertical pipe sections.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFB3407400)the National Natural Science Foundation of China(Grant No.52475386,Grant No.52025058).
文摘In the present study,three layers of aluminum(Al)and a single layer of copper(Cu)were joined by resistance rolling welding(RRW)and the impact of welding velocity on microstructure,mechanical property and electrical property was investigated.The results showed that the welding velocity was identified as the most significant parameter.With decreasing the welding velocity from 11 mm/s to 1 mm/s,the mechanical property of the joints initially showed an increase,reaching a maximum coach-peel peak load of 185.25 N,due to the larger well bonded region,then decreased owing to the high-temperature softening of the base metal.The elec-trical resistance of the joint demonstrated a consistent varying,characterized by an initial decrease owing to the larger completely bonded region and then increased with the decreasing welding velocity due to the excessive generation of Al2Cu with high electrical resistance.A cooling system was thus utilized to reduce the welding temperature to relieve the high-temperature softening,that suc-cessfully improved the welding quality of the joint by an 11.5%increase in the coach-peel peak load.
基金Supported by Open Funds for Innovation Platforms of Colleges and Universities in Hunan Province(15K066)National College Students'Innovative Entrepreneuria Training Program(201510553003)Research Study and Innovative Experiment Plan Project for College Students in Hunan Province(2015-499)~~
文摘In order to optimize the microwave-assisted extraction technology of polyphenols from Loropetalum chinense （R. Br.） Oliv., the effects of microwave power, ethanol concentration, solid to liquid ratio and extraction time on polyphenols extraction rate were investigated. On the basis of single-factor test, a four-factor and three-level orthogonal test was designed by response surface method to establish a mathematical model between the response value and various factors. The results showed that the intensity of effect of different influencing factor on polyphenols ex- traction rate ranked as microwave power＇s〉solid to liquid ratio＇s〉extraction time＇s〉 ethanol concentration＇s. The optimum microwave-assisted extraction conditions for polyphenols from L. chinense were as follows： extraction power 254 W, ethanol concentration 60%, extraction time 12.5 rain and solid to liquid ratio 1：17. Under the optimum extraction conditions, the extraction rate of polyphenols from L. chinense was 19.17%.
基金supported by the Technology Innovation Program of the Korea Evaluation Institute of Industrial Technology (KEIT)under the Ministry of Trade,Industry and Energy (MOTIE)of Republic of Korea (20012121)by the National Research Foundation of Korea (NRF)grant funded by the Korea government (MSIT) (2022M3J7A106294)。
文摘Polymer electrolyte membrane fuel cells(PEMFCs)are considered a promising alternative to internal combustion engines in the automotive sector.Their commercialization is mainly hindered due to the cost and effectiveness of using platinum(Pt)in them.The cathode catalyst layer(CL)is considered a core component in PEMFCs,and its composition often considerably affects the cell performance(V_(cell))also PEMFC fabrication and production(C_(stack))costs.In this study,a data-driven multi-objective optimization analysis is conducted to effectively evaluate the effects of various cathode CL compositions on Vcelland Cstack.Four essential cathode CL parameters,i.e.,platinum loading(L_(Pt)),weight ratio of ionomer to carbon(wt_(I/C)),weight ratio of Pt to carbon(wt_(Pt/c)),and porosity of cathode CL(ε_(cCL)),are considered as the design variables.The simulation results of a three-dimensional,multi-scale,two-phase comprehensive PEMFC model are used to train and test two famous surrogates:multi-layer perceptron(MLP)and response surface analysis(RSA).Their accuracies are verified using root mean square error and adjusted R^(2).MLP which outperforms RSA in terms of prediction capability is then linked to a multi-objective non-dominated sorting genetic algorithmⅡ.Compared to a typical PEMFC stack,the results of the optimal study show that the single-cell voltage,Vcellis improved by 28 m V for the same stack price and the stack cost evaluated through the U.S department of energy cost model is reduced by$5.86/k W for the same stack performance.
基金supported by the Sciences Platform Environment and Capacity Building Projects of GDAS(2021GDASYL-20210102005)the Guangdong Basic and Applied Basic Research Fund(2020A1515111031,2021A1515010939)+4 种基金the Young Elite Scientist Sponsorship Program by China Association for Science and Technology(CAST)(YESS20210269)Guangdong Provincial Special Support Program(2019BT02C629)Guangdong Academy of Sciences Development Special Fund Project(2022GDASZH-2022010107)Guangdong Academy of Sciences International Science and Technology Cooperation Platform Construction Project(2022GDASZH-2022010203-003)Guangzhou Key Field R&D Program(20200702008)。
文摘Fabrication of the Mg–9Al–1Zn–0.5Mn alloy with excellent mechanical performance using selective laser melting(SLM)technology is quite difficult owing to the poor weldability and low boiling point.To address these challenges and seek the optimal processing parameters,response surface methodology was systematically utilized to determine the appropriate SLM parameter combinations.Mg–9Al–1Zn–0.5Mn sample with high relative density(99.5±0.28%)and favorable mechanical properties(microhardness=95.6±5.28 HV_(0.1),UTS=370.2 MPa,and At=10.4%)was achieved using optimized SLM parameters(P=120 W,v=500 mm/s,and h=45μm).Sample is dominated by a random texture and microstructure is primarily constituted by quantities offine equiaxed grains(α-Mg phase),a small amount ofβ-Al_(12)Mg_(17) structures(4.96 vol%,including spherical:[2110]_(α)//[111]_(β)and long lath-like:[2110]_(α)//[115]_(β)or[1011]_(α)//[321]_(β)),and some short rod-shaped Al8Mn5 nanoparticles.Benefiting from grain boundary strengthening,solid solution strengthening,and precipitation hardening of various nanoparticles(β-Al12Mg17 and Al8Mn5),high-performance Mg–9Al–1Zn–0.5Mn alloy biomedical implants can be fabricated.Precipitation hardening dominates the strengthening mechanism of the SLM Mg–9Al–1Zn–0.5Mn alloy.
基金Foundation of Shanghai Science and Technology Committee,China (No. 19410711000)。
文摘Amyloid fibers are now considered as one of the possible therapeutic targets of neurodegenerative diseases due to their unique physicochemical properties and toxicity. To efficiently trace in real time how the drug inhibits protein amyloid fibrosis, it is necessary to study the conditions for rapid amyloid fibrosis. Insulin is selected as the model protein in vitro to explore the process of amyloid formation. The effects of the molar concentration of NaCl, pH and reaction temperature in the single-factor experiment are discussed and the response surface analysis is carried out. Amyloid fibrosis is labeled by Thioflavin-T(ThT). The optimal molar concentration of NaCl, pH and reaction temperature for insulin rapid amyloid fibrosis are 50.0 mmol/L, 2.02 and 54℃, respectively. With the addition of 0.1 mmol/L phenol, the half-time of insulin amyloid fibrosis is shortened from 5.4 h to 1.7 h. The insulin rapid amyloid fibrosis system provides a new approach for screening the protein amyloid fibrosis inhibitors.
基金supported by the National Hi-Tech Research and Development Program (863) of China (No.2007AA06Z349)the Natural Science Foundation Project of Chongqing (No.CSTC2008BB7333&7332)the State Key Laboratory of Pollution Control and Resource Reuse (No.PCRRF08006)
文摘The inhibition effects and mechanisms of chlorinated methane and acetylene on methanogenesis in the anaerobic digestion process of the biodegradable wastes were investigated.It was found that both chloroform and acetylene could effectively inhibit methanogens while the biodegradability of the wastes was not affected.Acetylene inhibited the activity of methanogens,while chloroform inhibited metabolic process of methanogenesis.A central composite design（CCD） and response surface regression analysis（RSREG） were employed to determine the optimum conditions and interaction effects of chloroform and acetylene in terms of inhibition effciency,production of volatile fatty acids（VAF） and molar ratio of propionic acid to acetic acid.Chloroform had significant effect on enhancing the production of VFA（F = 121.3;p 〈 0.01）,and acetylene promoted the inhibition effciency（F = 99.15;p 〈 0.05） more effectively than chloroform（F = 9.72;p 〉 0.05）.In addition,a maximum molar ratio of propionic acid to acetic acid of 1.208 was estimated under the optimum conditions of chloroform concentration of 9.05 mg/kg and acetylene concentration of 3.6×10^-3（V/V）.Hence,methanogens in the wastes can be inhibited while the stabilization process of the biodegradable wastes can still work well,as propionic acid generated during the inhibition process could hardly be utilized by methanogens.
基金supported by the National Key Research and Development Program of China(2019YFD1000103)National Natural Science Foundation of China(31872076)+1 种基金supported by the National Key Research and Development Program of China(2019YFD1000103)National Natural Science Foundation of China(31872076).
文摘The effect of soil nutrient content on fruit yield and fruit quality is very important.To explore the effect of soil nutrients on apple quality we investigated 200 fruit samples from 40 orchards in Feng County,Jiangsu Province.Soil mineral elements and fruit quality were measured.The effect of soil nutrient content on fruit quality was analyzed by artificial neural network(ANN)model.The results showed that the prediction accuracy was highest(R2=0.851,0.847,0.885,0.678 and 0.746)in mass per fruit(MPF),hardness(HB),soluble solids concentrations(SSC),titratable acid concentration(TA)and solid-acid ratio(SSC/TA),respectively.The sensitivity analysis of the prediction model showed that soil available P,K,Ca and Mg contents had the greatest impact on the quality of apple fruit.Response surface method(RSM)was performed to determine the optimum range of the available P,K,Ca,and Mg contents in orchards In Feng County,which were 10∼20 mg⋅kg^(−1),170∼200 mg⋅kg^(−1),1000∼1500 mg⋅kg^(−1),and 80∼200 mg⋅kg^(−1),respectively.The research also concluded that improving the content of available P and available Ca in orchard soil was crucial to improve apple fruit quality in Feng County,Jiangsu Province.
基金the Key Research and Development Special Project of Henan(Grant No.241111111300)the Major Scientific and Technological Special Project of Henan Province(Grant No.231100110200).
文摘As important factors in discrete elements,the physical parameters of watermelon seeds play a pivotal role in discrete element method.To obtain the discrete element parameters of watermelon seeds and improve the accuracy of the discrete element model,through a combination of actual and simulation tests,this research has calibrated the seeds’physical and contact parameters with the seed metering device.Employing the Plackett-Burman experiment,this study has identified three critical factors affecting the stacking angle:the static and rolling friction coefficients between seeds,and the collision recovery coefficient between seeds and plexiglass.Using the steepest-climbing design and Box-Behnken response surface analysis,this research has optimized these factors to values of 0.716,0.051,and 0.787,achieving a calibration error of just 2.60%.Verification with an air suction precision seed metering device confirmed the parameters’accuracy,with relative errors below 7.65%.The discrepancy between the simulation and actual test results,as measured by the qualified index error,is successfully reduced to below 4.38%.This study thus establishes a solid foundation for the structural optimization of air suction precision watermelon seed metering devices.
基金The authors acknowledge the College of Engineering,China Agriculture University for the laboratory support to conduct this research.This study was supported by the National Key R&D Program Projects(Grant No.2016YFD0701901).
文摘Maize picking is the main form of maize harvest in China.Maize picking loss accounts for a large proportion of the current maize harvest loss.An experimental study and a theoretical analysis were conducted to explore the influencing factors and rules of maize picking loss.First,the boundary conditions,established by analyzing the mechanism of maize picking,determined the influences of maize picking loss.Then,single-factor experiments and a central composite design(CCD)method were used to determine the influence of various factors and their interactions on maize picking loss.Finally,the models of kernel loss and ear loss were set up to determine the optimal parameter combination of maize picking harvest.Field experiment verification was conducted.The results indicated that the optimal parameters of the maize picking harvest were the rotational speed of pulling rollers of 1120 r/min,operating speed of 1.94 m/s,the inclination of the header of 18°and clearance between the picking plates of 30 mm.By establishing these optimal parameters,the kernel loss rate was 0.065%,and the ear loss rate was 0%.The obtained experimental results and regression models could be used to predict the performance of the maize picking harvest,guide the adjustment of header working parameters,and provide a theoretical basis for reducing the mechanical loss of maize harvesting.
基金supported by the earmarked fund for CARS-13Natural Science Foundation of Jiangsu Province (Grant No.BK20221187).
文摘Uniform crushed straw throwing and seed-sowing machines can achieve the processes of straw chopping,straw transport,sowing,fertilization,and straw mulching at the same time,which is widely used in many areas of China.Conveying device is one of the important components used to convey,elevate and throw straw.However,the problems of high power consumption and congestion affect the promotion of the machine.Therefore,the conveying device of uniform crushed straw throwing and seed-sowing machine was analyzed in order to determine its device operation mechanism.Kinematic and dynamic analyses of particles of crushed rice straw during lifting and dispersion are used to develop a flexible-body model of rod-shaped and agglomerate-shaped crushed straw and a coupling model including the mechanical structure of the device.By integrating computational fluid dynamics and the discrete element method,the gas-solid coupling theory in numerical simulations and motion analysis of crushed straw particles is used to determine how the flow field and motion characteristics affect the conveying performance.Besides,regression equations to describe the relationships between the factors and each assessment index were established by using the regression analysis and response surface analysis with the software Design-Expert.The effect of throwing blade speed X_(1),conveying volume of crushed straw X_(2),and pipeline diameter X_(3) on the throwing speed of crushed straw Y_(1) and specific power consumption Y2 were investigated.The highest throwing speed of crushed straw and lowest specific power consumption are the optimization goal.The results of optimization showed that the predict the best optimal parameters were 2000 r/min throwing blade rotational speed,1.4 kg/s conveying volume,and 220 mm pipeline diameter,the planter achieved a throwing speed of 12.2 m/s and specific power consumption of 9179 m^(2)/s^(2).And then a field test verification was conducted.The planter achieved a throwing speed 12.4 m/s and specific power consumption 9070 m^(2)/s^(2) while selecting the best optimal parameters.Thus,the optimal parameters can provide a high-performance operation and satisfy the actual operation requirements The results provide a theoretical basis and data support for seeding technology innovation and equipment optimization to ensure uniform crushed straw throwing in dense rice stubble fields.
基金financially supported by National Key Research and Development Program of China(2020YFA0710000)National Natural Science Foundation of China(U22A20391,22308274)+2 种基金Postdoctoral Fellowship Program of CPSF(GZB20240600,2023TQ0265,2024M752589)Innovation Capability Support Program of Shaanxi(NO.2023-CX-TD-26)the Programme of Introducing Talents of Discipline to Universities(B23025)。
文摘The plasma-coupled electrocatalytic cascade technology with NO_x~-as intermediate product is a potential method to realize green ammonia synthesis.The matching of the formation rate and consumption rate of NO_(2)^(-)as the main absorption product is an important prerequisite for the system to achieve stable operation.Therefore,this paper firstly emphasizes the importance of operating parameters on the cascade system based on the single factor experiment.Secondly,the empirical equation between electrocatalytic operating conditions and NO_(2)^(-)consumption rate was established by response surface analysis.Based on this equation,the electrocatalytic operating parameters were optimized to achieve the dynamic equilibrium between NO_(2)^(-)formation rate and consumption rate.Finally,the techno-economic assessment model was established to calculate the levelized cost of ammonia based on the cascade system,and the single-variable sensitivity analysis was performed to provide the clear guidance for cost reduction.
