Optimization of Center of Gravity Position and Anti-Wave Plate Angle of Amphibious Unmanned Vehicle Based on Orthogonal Experimental Method

When the amphibious vehicle navigates in water,the angle of the anti-wave plate and the position of the center of gravity greatly influence the navigation characteristics.In the relevant research on reducing the navigation resistance of amphibious vehicles by adjusting the angle of the anti-wave plate,there is a lack of scientific selection of parameters and reasonable research of simulation results by using mathematical methods,and the influence of the center of gravity position on navigation characteristics is not considered at the same time.To study the influence of the combinations of the angle of the anti-wave plate and the position of the center of gravity on the resistance reduction characteristics,a numerical calculation model of the amphibious unmanned vehicle was established by using the theory of computational fluid dynamics,and the experimental data verified the correctness of the numerical model.Based on this numerical model,the navigation characteristics of the amphibious unmanned vehicle were studied when the center of gravity was located at different positions,and the orthogonal experimental design method was used to optimize the parameters of the angle of the anti-wave plate and the position of the center of gravity.The results show that through the parameter optimization analysis based on the orthogonal experimental method,the combination of the optimal angle of the anti-wave plate and the position of the center of gravity is obtained.And the numerical simulation result of resistance is consistent with the predicted optimal solution.Compared with the maximum navigational resistance,the parameter optimization reduces the navigational resistance of the amphibious unmanned vehicle by 24%.

A Spider Monkey Optimization Algorithm Combining Opposition-Based Learning and Orthogonal Experimental Design

As a new bionic algorithm,Spider Monkey Optimization(SMO)has been widely used in various complex optimization problems in recent years.However,the new space exploration power of SMO is limited and the diversity of the population in SMO is not abundant.Thus,this paper focuses on how to reconstruct SMO to improve its performance,and a novel spider monkey optimization algorithm with opposition-based learning and orthogonal experimental design(SMO^(3))is developed.A position updatingmethod based on the historical optimal domain and particle swarmfor Local Leader Phase(LLP)andGlobal Leader Phase(GLP)is presented to improve the diversity of the population of SMO.Moreover,an opposition-based learning strategy based on self-extremum is proposed to avoid suffering from premature convergence and getting stuck at locally optimal values.Also,a local worst individual elimination method based on orthogonal experimental design is used for helping the SMO algorithm eliminate the poor individuals in time.Furthermore,an extended SMO^(3)named CSMO^(3)is investigated to deal with constrained optimization problems.The proposed algorithm is applied to both unconstrained and constrained functions which include the CEC2006 benchmark set and three engineering problems.Experimental results show that the performance of the proposed algorithm is better than three well-known SMO algorithms and other evolutionary algorithms in unconstrained and constrained problems.

Optimization of extraction of polyphenols from pomegranate peel by orthogonal experiment design and antioxidant activity

The aim of this study was to investigate the extraction process and antioxidant activity of polyphenols from Yunnan Mengzi pomegranate peel.Single factor and orthogonal test were used as optimize the extract rate(ER)of polyphenols from pomegranate peel(PGP).The polyphenols antioxidant activity was evaluated by DPPH·,·OH and total reducing ability,and compared with that of Vc.The optimum extraction conditions of polyphenols were as follows:ethanol concentration of 50%,liquid-solid ratio of 50:1,extraction temperature of 90°C,extraction for 4 h.Under these conditions,the ER of polyphenols from GPG was 8.15%.The results showed that the scavenging effects of polyphenols and Vc on DPPH·,·OH increased with increasing concentration,and the scavenging effect of polyphenols on DPPH·was higher than Vc in rang of 0.1-1.6µg/mL.When the concentration is greater than 0.6µg/mL,the scavenging effects of plyphenols on·OH is higher than Vc.The total reducing ability of polyphenols from PGP improved with the increase of concentration,and when the concentration was 8µg/mL,the total reducing ability was 114 U/mL.

Determination of Total Flavonoids in Leaves of Paliurus ramosissimus and Orthogonal Experiment Optimization Process

[Objectives] To screen the optimal extraction conditions of flavonoids from leaves of Paliurus ramosissimus( Lour.) Poir.,measure the content of flavonoids in leaves of P. ramosissimus. using the Microplate Reader,and provide experimental basis for the development of medicinal resources of P. ramosissimus. [Methods] The ultrasonic extraction method was adopted and orthogonal design was carried out to study the effects of ethanol concentration( A),ultrasonic time( B),the solid-to-liquid ratio( C) on the extraction of flavonoids from leaves of P. ramosissimus. The Microplate Reader was used to measure the content of flavonoids in leaves of P. ramosissimus. in different extraction conditions,P. ramosissimus. and the optimal extraction conditions were used to measure the content of flavonoids from leaves of P. ramosissimus.[Results]Effects of the ultrasonic extraction method on the extraction rate of flavonoids from leaves of P. ramosissimus: extraction times >ethanol concentration > Ultrasound time > solid-liquid ratio. The screened optimal extraction process was: ethanol concentration of 65%,the solid-to-liquid ratio of 1∶ 25,ultrasonic time of 2 h and extraction times Under this condition,the extraction rate of total flavonoids in leaves of P. ramosissimus. was 2. 56%. [Conclusions] This method is simple and feasibility,reliable,and suitable for rapid measurement with large samples.

CVD Method for Carbon Nanotubes Preparation Based on Orthogonal Experiment Using C_3H_6

Carbon nanotubes (CNTs) have potential applications in many fields, chemical vapor deposition (CVD) is an effective method for CNTs preparation. By CVD, the catalytic pyrolysis temperature, pyrolysis time and the size of the raw gas flow have a great influence on yield rate of CNTs and their form. In this paper, the orthogonal experiment analysis method is used for studying the influence factors of yield rate of CNTs. Research results show that, in the suitable temperature range of preparing CNTs, there is relatively more CNTs with excellent morphology, otherwise, if the temperature is too low, the growth of CNTs will not be sufficient; if the temperature is too high, then CNTs will be generated with excessive defects; with longer growth time of suitable pyrolysis of CNTs, higher yield of CNTs will be obtained; CNTs morphology with reaction time is not proportional; too low or too high raw gas flow rate is not conducive to the growth of CNTs. We have found the optimum conditions for the CNTs preparation: pyrolysis temperature 68 degrees C, pyrolysis time 35 min, propylene flow rate of 180 mL/min. The results have a reference value for the preparation of CNTS and their composites.

Application of Orthogonal Experiment in EDM Using the Suspended Powder Fluid

To solve the problems of EDM when using the ordinary fluid and mold manufacturing,this paper provides the orthogonal experiment in the suspended powder fluid,which can optimize the main process parameters.And it also achieves the technology of EDM in the suspended powder fluid primarily.

Parameters optimization for direct contact membrane distillation based on orthogonal experiment

Parameter optimization integrating operation parameters and structure parameters for the purpose of high permeate flux,high productivity and low exergy consumption of direct contact membrane distillation (DCMD) process was conducted based on Taguchi experimental design. L16(45) orthogonal experiments were carried out with feed inlet temperature,permeate stream inlet temperature,flow rate,module packing density and length-diameter ratio as optimization parameters and with permeate flux,water productivity per unit volume of module and water production per unit exergy loss separately as optimization objectives. By using range analysis method,the dominance degree of the various influencing factors for the three objectives was analyzed and the optimum condition was obtained for the three objectives separately. Furthermore,the multi-objectives optimization was performed based on a weight grade method. The combined optimum conditions are feed inlet temperature 75℃,packing density 30% ,length-diameter ratio 10,permeate stream inlet temperature 30 ℃ and flow rate 25 L/h,which is in order of their dominance degree,and the validity of the optimization scheme was confirmed.

Optimization of in vitro Regeneration System of Benihoppe Strawberry (Fragaria × ananassa Duch.) with Orthogonal Experiment Design

[Objective] This study aimed to optimize the in vitro regeneration system of Benihoppe strawberry. [Method] Based on orthogonal experiment, the effects of different medium types, plant growth regulator types and concentrations on the regeneration of adventitious shoots of Benihoppe strawberry leaves were in- vestigated. [Result] IBA is an important factor affecting the multiplication of adventitious shoots of Benihoppe strawberry leaves; the optimal induction medium is MS ＋ 2.0 mg/L TDZ ＋ 0.2 mg/L IBA, with an induction rate of 90.00% ; the optimal differentiation medium is MS ＋ 2.0 mg/L 6-BA ＋ 0.2 mg/L IBA, with a differentiation rate of 8.1% ; the optimal multiplication medium is MS ＋ 1.0 mg/L 6-BA ＋ 0.2 mg/L IBA, with an average multiplication rate of each adventi- tious shoot of 7.67 ; the optimal subculture medium is MS ＋ 0.5 mg/L 6-BA ＋ 0. 1 mg/L 2, 4-D, with an average seeding height in each treatment of 5.98 cm; the optimal rooting medium is 1/2MS ＋ O. 5 mg/L 6-BA ＋ 0. 1 mg/L 2, 4-D, with an average number of roots in each treatment of 4.5. [ Conclusion] This stud- y laid the foundation for further investigating the genetic transformation of strawberry and improving the quality of strawberry at the genetic level.

Optimization of Ultrasonic Extraction Process of Total Flavonoids from Mulberry Leaves by Orthogonal Experiment

In this study, by using mulberry leaves as raw materials, ultrasonic extraction process of total flavonoids from mulberry leaves was optimized by orthogonal experiment. Results showed that the maximum yield of total flavonoids （6.1% ） was obtained from mulberry leaves with addition of 45 times the volume of water by ultrasonic extraction at 55 ℃ for three times, 55 min each. According to the verification test, the optimized technical process was reasonable and feasible with high stability.

Optimization of Conditions for Extracting Luteolin from Ternate Grape Fern Herb by an Orthogonal Experiment

[Objectives] This study was conducted to optimize the extraction process of luteolin, a natural product of Ternate Grape Fern Herb, so as to provide a theoretical research basis for the chemical composition, pharmacological research and preparation development of Ternate Grape Fern Herb. [Methods] The effects of four factors including ultrasonic extraction time, liquid-to-material ratio, ultrasonic extraction temperature and ethanol concentration on extraction yield of luteolin from Ternate Grape Fern Herb were investigated by the ultrasonic-assisted extraction technology, through a single-factor experiment and an orthogonal experiment based on the single-factor experiment, and the experimental data was subjected to variance analysis and SSR analysis of the significance of differences between groups by SPSS20.0 software to select the optimal extraction process conditions. [Results] The optimal extraction process conditions were as follows: ultrasonic extraction time 25 min, liquid-to-material ratio 25∶1 ml/g, ethanol volume fraction 60%, ultrasonic extraction temperature 85 ℃. [Conclusions] The results were verified, and it was determined that the ultrasonic-assisted extraction process established in this study is reasonable and reliable, and can be used for the extraction of luteolin.

Simulation analysis of hot dip galvanizing process parameters based on orthogonal experimental design

An iron and steel company＇ s hot galvanizing technology was chosen as the object. An orthogonal experimental scheme with 5 factors of mixed level was designed, according to the various factors affecting the distribution of slag. For each scheme, the amount of slag and slag height in different orthogonal schemes by simulation were obtained with FLUENT software. Then, range and variance analyses were selected to compare the trend of slag height in the different process parameters of the hot dip galvanizing process. Finally, the optimal combination of the process parameters was obtained.

Global optimization of process parameters for low-temperature SiN_(x) based on orthogonal experiments

Low-temperature silicon nitride(SiNx)films deposited by plasma-enhanced chemical vapor deposition(PECVD)have huge application potential in the flexible display.However,the applicability of SiNx largely depends on the film’s general properties,including flexibility,deposition rate,residual stress,elastic modulus,fracture strain,dielectric constant,refraction index,etc.Process optimization towards specific application by conventional experiment design needs lots of work due to the interaction of muti quality and process parameters.Therefore,an efficient global optimization approach for the process technology was proposed based on the Taguchi orthogonal experiment method considering muti-factor muti-responses.First of all,the Taguchi orthogonal experiment design and analysis was used to rank the influences of main process parameters on the quality characteristics,including radio frequency(RF)power,pressure,silane flow rate,ammonia flow rate and nitrogen flow rate.Then,the global optimization approach was carried out utilizing the multi-response optimizer considering the combination target of film formation rate,residual stress,dielectric constant,elastic modulus,fracture strain,refractive index.Finally,the optimal solution of the SiNx film was finally obtained and verified.

Effects of Machine Tool Configuration on Its Dynamics Based on Orthogonal Experiment Method

In order to analyze the influence of configuration parameters on dynamic characteristics of machine tools in the working space, the configuration parameters have been suggested based on the orthogonal experiment method. Dynamic analysis of a milling machine, which is newly designed for producing turbine blades, has been conducted by utilizing the modal synthesis method. The finite element model is verified and updated by experimental modal analysis （EMA） of the machine tool. The result gained by modal synthesis method is compared with whole-model finite element method （FEM） result as well. According to the orthogonal experiment method, four configuration parameters of machine tool are considered as four factors for dynamic characteristics. The influence of configuration parameters on the first three natural frequencies is obtained by range analysis. It is pointed out that configuration parameter is the most important factor affecting the fundamental frequency of machine tools, and configuration parameter has less effect on lower-order modes of the system than others. The combination of configuration parameters which makes the fundamental frequency reach the maximum value is provided. Through demonstration, the conclusion can be drawn that the influence of configuration parameters on the natural frequencies of machine tools can be analyzed explicitly by the orthogonal experiment method, which offers a new method for estimating the dynamic characteristics of machine tools.

Orthogonal Experiments on Direct Reduction of Carbon-bearing Pellets of Bayer Red Mud

To recycle residual iron efficiently in Bayer red mud, three-factor three-level orthogonal experiments on carbon-bearing pellets of Bayer red mud were conducted on the basis of their characteristics. The influences of CaO dosage, temperature and roast- ing time on total iron content and iron recovery of reduced iron powder were studied. Results showed that these factors slightly influenced iron recovery, but significantly influenced total iron content. The principal factor influencing total iron content was CaO dosage, followed by temperature and roasting time. An increase in CaO dosage could decrease total iron content, whereas an increase in temperature and an extension of roasting time could improve total iron content. The reduced iron powder with total iron content of 88.4 l% and iron recovery rate of 97.97% can be obtained under the optimal conditions of temperature of 1 275 ℃, roasting time of 60 min and CaO dosage of 7.5%. The X-ray diffraction （XRD） and scanning electron microscopy （SEM） analyses of the reduced pellets showed that iron minerals in red mud were almost completely reduced to metallic iron. The principal factor influencing the total iron content of reduced iron powder was the grain size of metallic iron particles. An increase in CaO dosage hindered the growth of metallic iron particles, whereas an increase in temperature and an extension of roasting time could neutralise the effect of CaO dosage. Therefore, CaO dosage should be decreased when iron minerals in red mud can be adequately reduced into metallic iron.

Excavation collapse of Hangzhou subway station in soft clay and numerical investigation based on orthogonal experiment method

This paper studies the excavation collapse at the Xianghu subway station on Hangzhou metro line 1.The objective is to present an overview of this case study and discuss the cause of the failure.Through field investigation and preliminary analysis,the reasons for the excavation collapse were the misuse of the soil parameters,over excavation,incorrect installation of steel struts,invalid monitoring data,and inadequate ground improvement.Finally,a small strain constitutive model was used for further analysis.In order to estimate damage efficiently,the orthogonal array(OA) was introduced for screening the key factor in the numerical experiments.Six estimated indexes including deformations and internal forces of the excavation were taken,and the effectiveness of four factors which may cause the collapse was evaluated.Through numerical experiments and interaction analysis,it is found that the deformation and internal force can be well controlled by jet grouting of the subsoil under the final cutting surface,but increasing the improvement ratio of the jet grouting cannot help optimize the excavation behavior efficiently,and without jet grouting and the fourth level struts,the deformation and internal force of the excavation in this case will far surpass the allowable value.

Synthesis and Characterization of PVA-HA-Silk Composite Hydrogel by Orthogonal Experiment

PVA-HA-Silk composite hydrogel was synthesized with polyvinyl alcohol （PVA）, nano-hydroxyapatite （HA） and natural silk by using the method of repeated freezing and thawing. A series of tests were performed to study water content, stress relaxation behavior, elastic modulus, and creep characteristics of PVA-HA-Silk composite hydrogel. Orthogonal experimental design method was used to analyze the influence degree of PVA, HA and silk （three kinds of raw materials） on mechanical properties and water content of the PVA-HA-Silk composite hydrogel to select the best material ratio according to their overall performance. The results demonstrate that the mass percentage of PVA has the greatest impact on the water content, followed by HA and silk. Compression stress-strain variation of PVA-HA-Silk composite hydrogel presents a nonlinear relationship, which proves that it is a typical viscoelastic material. Comparing the mechanical properties of 16 formulas, the formula of PVA-HA-silk composite hydrogel with mass percentage of PVA 15%, HA 2.0% and silk 1.0% is the best.

Orthogonal design of experiment and analysis of abrasive water jet cutting on carbon fiber reinforced composites

The carbon fiber reinforced composite is a new type of composite material with an excellent property in strength and elastic modulus,and has found extensive applications in aerospace,energy,automotive industry and so on.However,this composite has a strict requirement on processing techniques,for example,brittle damage or delamination often exists in conventional processing techniques.Abrasive water jet machining technology is a new type of green machining technique with distinct advantages such as high-energy and thermal distortion free.The use of abrasive water jet technique to process carbon fiber composite materials has become a popular trend since it can significantly improve the processing accuracy and surface quality of carbon fiber composite materials.However,there are too many parameters that affect the quality of an abrasive water jet machining.At present,few studies are carried out on the parameter optimization of such a machining process,which leads to the unstable quality of surface processing.In this paper,orthogonal design of experiment and regression analysis were employed to establish the empirical model between cutting surface roughness and machining process parameters.Then a verified model was used to optimize the machining process parameters for abrasive water jet cutting carbon fiber reinforced composites.

Cavitation Optimization for a Centrifugal Pump Impeller by Using Orthogonal Design of Experiment

Cavitation is one of the most important performance of centrifugal pumps. However, the current optimization works of centrifugal pump are mostly focusing on hydraulic efficiency only, which may result in poor cavitation performance. Therefore, it is necessary to find an appropriate solution to improve cavitation performance with acceptable efficiency. In this paper, to improve the cavitation performance of a centrifugal pump with a vaned diffuser, the influence of impeller geometric parameters on the cavitation of the pump is investigated using the orthogonal design of experiment （DOE） based on computational fluid dynamics. The impeller inlet diameter D1, inlet incidence angle Aft, and blade wrap angle ~0 are selected as the main impeller geometric parameters and the orthogonal experiment of L9（3＂3） is performed. Three-dimensional steady simulations for cavitation are conducted by using constant gas mass fraction model with second-order upwind, and the predicated cavitation performance is validated by laboratory experiment. The optimization results are obtained by the range analysis method to improve cavitation performance without obvious decreasing the efficiency of the centrifugal pump. The internal flow of the pump is analyzed in order to identify the flow behavior that can affect cavitation performance. The results show that D1 has the greatest influence on the pump cavitation and the final optimized impeller provides better flow distribution at blade leading edge. The final optimized impeller accomplishes better cavitation and hydraulic performance and the NPSHR decreases by 0.63m compared with the original one. The presented work supplies a feasible route in engineering practice to optimize a centrifugal pump impeller for better cavitation performance.

Optimization of Extraction Process for Total Flavonoids from Penthorum chinense Pursh and Comparison of Their Contents from Different Parts

[Objectives]This study was conducted to optimize the extraction process of total flavonoids from Penthorum chinense Pursh and compare their contents from different parts.[Methods]Single factor and orthogonal experiments were designed to optimize the extraction process of total flavonoids from P.chinense Pursh with the volume fraction of ethanol,the ratio of material to liquid,heating reflux extraction time and extraction times as factors,and the content of total flavonoids as the index.A verification test was carried out.The optimized extraction process was adopted to compare the contents of total flavonoids from different parts of P.chinense Pursh.[Results]The best extraction process was extracting the powder of P.chinense Pursh for 2.0 h with 20 times of 55%ethanol by reflux twice.Under this condition,the contents of total flavonoids were 3.63%,8.90%,11.28%,and 4.36%from stems,leaves,flowers and whole grass of P.chinense Pursh,respectively.[Conclusions]The process is reasonable,feasible and stable,and can effectively extract total flavonoids from P.chinense Pursh.The contents of total flavonoids from different parts of P.chinense Pursh were quite different,and the value was higher in the leaves and flowers,so the proportions of leaves and flowers should be paid attention to in the industrial processing of P.chinense Pursh.

Orthogonal Test Design for Optimization of the Extraction of Flavonid from the Fructus Gardeniae

Objective It is imperative to provide some consistent experimental results for the extraction of flavonid from Fructus Gardeniae. Methods The key extraction parameters that influenced the yield of flavonid from Fructus Gardeniae were optimized by employing an orthogonal experiment [L9（3）4], including the ratio of buffer solution （Na2B4O7· 10H2O） to raw material, concentration of Fructus Gardeniae in extracting solution, extraction time and pH of buffer solution. An UV/Vis detector was used to perform the qualitative and quantitative analyses of the extracted flavonid with the using of the standard sample. Results The maximum extraction yield of the crude extract was 5.0533 （mg/g） after 20 min when the mass ratio of Na2B4O7 · 10H2O to raw material was 0.4%, the concentration of Fructus Gardeniae in the extraction solution was 1/12 （g/mL）, and pH of buffer solution was 4.5. The positive reactions to the Molish and HCI-Mg tests suggested that the extracted compound was flavonoid, and FTIR measurements also identified the presence of flavonoid in the extracts. Conclusion This work is expected to provide a basis for further research, development, and utilization of Fructus gardenia in flavonid extraction.