Experimental Response Surface Research Articles

Optimization of extraction process for classic prescription Yihuang Decoction based on Box-Behnken design-response surface methodology, standard relation, and analytic hierarchy process combined with entropy weight method

Based on the concept of quality by design(QbD), the Box-Behnken design-response surface methodology combined with standard relation(SR) and analytic hierarchy process(AHP)-entropy weight method(EWM) was applied to optimize the extraction process of the classic prescription Yihuang Decoction. The content of geniposidic acid, phellodendrine hydrochloride, and berberine hydrochloride in Yihuang Decoction, the extract yield, and fingerprint similarity were used as the critical quality attributes(CQAs) of the extraction process. The extraction time, water addition, and extraction times were used as the critical process parameters(CPPs). After determining the levels of each factor and level through single-factor experiments, response surface experiments were designed according to the Box-Behnken principle, and the experimental results were analyzed. The SR between each sample and the reference sample under various evaluation indicators of different extraction parameters was calculated. The weights of the five evaluation indicators were determined using AHP-EWM, followed by comprehensive evaluation. A function model between CPPs and CQAs characterized by comprehensive scores was established to predict the optimal extraction process parameters. In the final comprehensive weight coefficients, the yield rate accounted for 43.1%, and the content of berberine hydrochloride, phellodendrine hydrochloride, and geniposidic acid accounted for 35.1%, 6.3%, and 15.5%, respectively. After comprehensive score analysis with SR, the established second-order polynomial model was statistically significant(P<0.01, and the lack of fit was not significant). The predicted optimal extraction conditions for Yihuang Decoction were determined as follows: 8-fold volume of water, extraction time of 1.5 h, and extraction once. The mean comprehensive score of the validation experiment was 85.77, with an RSD of 0.99%, and it met the quality control stan-dards for the reference sample of Yihuang Decoction. The results indicate that the optimized extraction process for Yihuang Decoction is stable and reliable, and the water extract is close in quality attributes to the reference sample. This can serve as a foundation for the research and development of granules in the future. Box-Behnken design-response surface methodology combined with SR and AHP-EWM can provide references for the modern extraction process research of other classic prescriptions.

An optimization model of tractor clutch pedal design parameters based on lower limb biomechanical characteristics

The design of tractor pedal affects operator's comfort, working efficiency, and occupational health. To optimize tractor clutch pedal design parameters, we conducted a single-factor experiment and a response surface experiment based on a biomechanical model. The experimental indicators included the biomechanical loads of major activated muscles and joints of the lower limb, and the experimental factors comprised pedal-seat horizontal distance L, pedal-seat vertical distance H, and pedal spring stiffness k. The results indicate that L and H mainly influence the loads of semitendinosus and hip. Semitendinosus activity and hip torque first decreased and then increased with increasing L (or H), reaching the lowest level at 82 cm of L (or 42 cm of H). The increase in k led to gradual decreases in iliopsoas activity and increases in semitendinosus, rectus femoris, soleus activities, and ankle torque, as well as a first decreasing and then increasing trend of hip and knee torques. The overall biomechanical loads of the lower limb first declined and then grew with increasing L, H, and k. The optimal range of clutch pedal design parameters was calculated to be {(L, H, k) | 36≤L ≤ 40, 72≤H ≤ 76, 14≤k ≤ 22} when using the response surface method. Within this range, muscle activity and joint torque were reduced by 14.2% and 51.6%, respectively, indicating effective alleviation of the lower limb biomechanical loads. This study provides important implications for the biomechanical analysis of tractor operator-pedal interaction system and lays a foundation for improving the design and comfort of tractors.

Optimization of a Microencapsulation Process Using Oil-in-Water (O/W) Emulsion to Increase Thermal Stability of Sulforaphane.

Sulforaphane (SFN) is a bioactive compound widely studied for its potential applications in pharmaceutical, nutraceutical, and food industries since it offers health benefits due to its nature as a Phase 2 enzyme inducer. Its application in the food industry has been limited because SFN is unstable at high temperatures in an aqueous milieu. An option to increase SFN stability and protect it from thermal degradation is microencapsulation. The aim of this work was to optimize a microencapsulation process using oil-in-water emulsion to increase the thermal stability of SFN. The operation conditions that gave the highest entrapment efficiency were determined via experimental design and response surface methodology. Thermal degradation of microencapsulated SFN was studied at 37, 50, 60, and 70 °C. The optimum microencapsulation conditions were 8 min stirring, SFN/Gum Arabic ratio of 0.82, and surfactant/oil ratio of 1.0, resulting in an entrapment efficiency of 65%, which is the highest reported so far. The thermal stability of microencapsulated SFN was greatly enhanced compared with free SFN, with a 6-fold decrease in the degradation kinetic constant and a 41% increase in the activation energy. These results will contribute to a more efficient incorporation of SFN in various food matrices and explore new microencapsulation technologies to maximize the efficiency and stability of SFN.

Optimization of low-grade coal and refuse-derived fuel blends for improved co-combustion behavior in coal-fired power plants.

This study is aimed at utilizing three waste materials, i.e., solid refuse fuel (SRF), tire derived fuel (TDF), and sludge derived fuel (SDF), as eco-friendly alternatives to coal-only combustion in co-firing power plants. The contribution of waste materials is limited to ≤5% in the composition of the mixed fuel (coal + waste materials). Statistical experimental design and response surface methodology are employed to investigate the effect of mixed fuel composition (SRF, TDF, and SDF) on gross calorific value (GCV) and ash fusion temperature (AFT). A quadratic model is developed and statistically verified to apprehend mixed fuel constituents' individual and combined effects on GCV and AFT. Constrained optimization of fuel blend, i.e., GCV >1,250 kcal/kg and AFT >1,200 °C, using the polynomial models projected the fuel-blend containing 95% coal with 3.84% SRF, 0.35% TDF, and 0.81% SDF. The observed GCV of 5,307 kcal/kg and AFT of 1225 °C for the optimized blend were within 1% of the model predicted values, thereby establishing the robustness of the models. The findings from this study can foster sustainable economic development and zero CO2 emission objectives by optimizing the utilization of waste materials without compromising the GCV and AFT of the mixed fuels in coal-fired power plants.

Calibration and Experiments on the Parameters of the Bonding Particle Model of Eucommia ulmoides Oliver Samara Based on the Discrete Element Method

The calibration of the discrete element model of EUO samara was conducted in response to the lack of discrete element simulation models and parameters in the development of mechanical hulling technology and equipment of EUO samara. The EUO samara was modeled based on the Hertz–Mindlin with bonding model, and its relevant parameters were measured by physical experiments. Among them, maximum shear force was used as the evaluation index, virtual calibration experiments were conducted for the bonding parameters by the single-factor experiments, and the two-level factorial experiment, the steepest climb experiment, and the Box–Behnken response surface experiment were also used. The results showed that the relative error between the simulated and measured maximum shear force is 0.93%; the model and parameter calibration results established by this research can be used for discrete element simulation research, which is of guiding significance for the research and development of hulling equipment of EUO samara.

Characterization and computational modeling of continuous-fiber prepreg ply-ply interaction behavior

Ply-ply interaction behavior critically affects wrinkle formation during composite forming. This paper presents a computational model of the ply-ply interaction behavior of woven thermoset prepreg fabrics. The computational model includes visco-elastic, pressure-sensitive adhesion behavior, as well as a yield behavior that allows the deformation to transition from adhesion to friction. The model is based on the analysis and observations of double-lap shear factor effect screening tests and of total slip test measurements. To validate the computational model, finite element simulations are compared to experimental response surface tests for various pressures and deformation rates. The comparison shows that the computational model closely captures the load-deformation response of the ply-ply interaction. This computational model can be used in a forming process simulation to predict wrinkle formations.

Optimization Studies on the Coagulation–Flocculation Process for PWW Treatment Using Cactus oputia Extract: Comparative Studies for Performance Evaluation

The treatment of Paint Waste Water, PWW is an important global issue for the minimization of water pollution especially in a developing country like Nigeria. The coagulation–flocculation process using Cactus Oputia Extract, COE as natural coagulant is reported for PWW treatment in the present study. The important process parameters pH, settling time, coagulant dosage and initial concentration were optimized using design of experiments (DOE). A full factorial composite experimental design and response surface methodology (RSM) were used to obtain the optimum values of the parameters. Also utilized in this study were Artificial Neural Network, ANN and Adaptive Neuro Fuzzy Inference System, ANFIS for performance evaluation. Using the numerical optimization technique of the design expert software, a combination of factors which concurrently fulfil the requirements placed on the response variable were determined. The best effluent removal efficiency was predicted to be 89.78% at the optimum values of the process parameters pH 6, settling time 30 mins, coagulant dosage 3 g and initial concentration 1.2 mg/l in this study.

Design and Experiment of Double-Row Seed-Metering Device for Buckwheat Large Ridges

This article focuses on the low accuracy, poor stability, and other shortcomings of the traditional outer-groove buckwheat seed-metering wheel. A wheel-type large-ridge double-row seed-metering device with inner seed-filling holes was designed. The seed-metering device’s structural composition, working principle, and main technical parameters are clarified. The structural parameters of the seed-metering device shell and the seed-metering wheel are determined based on the force analysis, movement trajectory, and physical characteristics of the buckwheat grains. This experiment uses the JPS-12 metering device performance experiment bench for bench experimenting. The experiment uses the seed-metering device’s rotation speed, the seed position’s height, and the seed wheel’s aperture as experiment factors. Based on the experiment indicators of the qualified rate of number of holes and the grain damage rate, we used Design-Expert12 software to design single-factor, response surface, and verification experiments. The experiment results show that the best parameter combination is a seed-metering device rotation speed of 67 r/min, a seed position height of 115 mm, and a seed wheel aperture of 8 mm. In the optimal parameters, the qualified rate of the number of holes is 90.23%, and the grain damage rate is 0.62%. The experiment indicators meet the operational requirements of the buckwheat seeding device. The design and experimenting of the buckwheat large-ridge double-row seeding device provide a reference for further research on buckwheat seeding.

Design and experiment of a centrifugal filling and cleaning high-speed precision seed metering device for maize

In this paper, a centrifugal filling and cleaning high-speed precision seed metering device for maize is designed based on the principle of centrifugal force generated by high-speed circular motion of seeds. Through theoretical analysis and calculation, the seeding tray and front shell of the seed metering device are designed so that the seeds can use centrifugal force for filling, cleaning, releasing, and returning. The seed metering device has a simple structure and can perform high-speed and precise seeding. A response surface experiment of central composite design was conducted with feeding and seeding speeds as experimental factors, and the omission rate, repeated rate, and pass rate as performance evaluation indexes. Through response surface experiment optimization, it was deduced that the highest seeding performance was achieved when the feeding and seeding speeds were 18.72 seeds/s and 15.12 km/h, respectively. Under these conditions, the omission, repeated, and pass rates were 2.21, 5.21, and 92.58%, respectively. The results of response surface experiment showed that, when the seeding speed of the centrifugal filling and cleaning high-speed precision seed metering device for maize is in the range of 10–20 km/h, the pass rate can be greater than 90%. In addition, the speed curve of feeding and seeding fitted from the bench experiment results is effective and reliable, which allows the seed metering device to achieve a precision seeding in a speed range of 10–20 km/h. The power of the air-suction seed metering device is 470.24 W when seeding at a speed of 14 km/h. Moreover, the power of the centrifugal filling and cleaning high-speed precision seed metering device is only 10.94 W when seeding at a speed of 20 km/h, and the energy consumption during seeding is much lower than that of the air-suction seed metering device, which performs cleaner production.

Optimization of the physical properties of recycled plastic hybrid composites reinforced with rubberwood flour and crab shell flour for underwater use

This research aimed to optimize the composition and physical properties of recycled high-density polyethylene (rHDPE) hybrid composites reinforced with rubberwood flour (RWF) and crab shell flour (CS) for application in water immersion. The effects of composition and deterioration in physical properties after immersion in different water conditions (distilled water and seawater) were investigated. D-optimal mixture experimental design and response surface methodology were applied. The findings showed that all the physical properties deteriorated with an increase in immersion times. The increasing addition of CS increased the density, water absorption, thickness swelling, and surface roughness of the samples before and after being immersed in distilled water and seawater. Further, the results revealed that the optimal composition for application in water immersion included 60.0 wt% rHDPE, 29.5 wt% RWF, 5.6 wt% CS, 3.5 wt% maleic anhydride-grafted polyethylene, 0.5 wt% ultraviolet stabilizers, and 1.0 wt% lubricant with a desirability score value of 95.80 %. The predicted response of density, color measurement, surface roughness, water absorption, and thickness swelling were 0.89 g/cm3, 10.11, 4.59 µm, 10.27 %, and 7.73 %, respectively. Based on the findings in this research, the effective application of naturally sourced additives in composite products, and using the optimized rHDPE, RWF, and CS contents would enable the development of alternative materials for applications in water immersion.

RESPONSE SURFACE METHODOLOGY APPLIED TO ELECTRO-FENTON PROCESS FOR DEGRADATION OF RED BEMACID AS TEXTILE DYE MODEL

The textile industry produces persistent organic pollutants (POPs) that pose significant risks to ecosystems because of their toxic and hazardous nature. Consequently, there is an urgent requirement for the development of effective techniques to treat the effluents and remove these compounds. This work studied the viability of the Electro-Fenton (EF) process as a potential alternative for treating textile wastewater contaminated with POPs. A batch electrochemical reactor, equipped with a platinum grid cathode and stainless-steel sacrificial anode, was utilized to eliminate Red Bemacid (RB) dye. The study investigated the impact of four key operational parameters: (i) stirring speed (rpm), (ii) oxygen flow rate (L/min), (iii) supporting electrolyte concentration [Na2SO4] (mg/L), and (iv) current intensity (A), as well as their interactions on RB removal. To perform this, Central Composite Experimental Design (CCD) and Response Surface Methodology (RSM) were employed. Under optimized EF conditions for RB removal (stirring speed = 205.09 rpm, oxygen flow rate = 0.20 L/min, current intensity = 0.306 A, and supporting electrolyte concentration = 0.09 M), the EF process demonstrated exceptional removal efficiency, achieving approximately 94.51% removal of RB. The obtained results showed that the kinetic data of RB removal were in good agreement with the Behnajady-Modirshahla-Ghanbery (BMG) model. The CCD analysis revealed that the main effect of the current intensity had a significant impact on RB removal, as well as the interaction of all paired variables.

The effect of sliding shear combined sugarcane basecutter on the cutting quality of sugarcane stubble

AbstractAs an important cash crop, sugarcane played an important role in the development of national economy. In response to the problem of severe stubble splitting caused by unsupported basecutting, the interaction between the basecutter and stalk were analyzed under the supported and unsupported basecutting modes, and the cutting force model was also established. The theoretical analysis results showed that supported basecutting could effectively reduce the bending resistance and inertia force of the stem, and avoid significant deformation of the stem. To some extent, supported basecutting could ensure the cutting quality of sugarcane stubble. The basecutting process of supported and unsupported basecutting were comparative analyzed based on ABAQUS. The simulation results showed that supported cutting could effectively reduce the maximum cutting stress and limit the displacement of the stem, and it could effectively ensure the stability of sugarcane stubble. The test bench was built with adjustable feeding speed (FS), rotational speed (RS), sugarcane cluster diameter (CD), and cutting inclination angle (CA). Based on the Box–Behnken center combination design scheme, the response surface experiments were conducted with the stubble splitting rate as experimental indicators. The analysis of variance showed that CD and CA had a significant impact on the splitting rate, with the degree of influence being: CD > CA > FS > RS. The model was optimized and solved, and the optimal parameter combination was the feeding speed of 1.4 m/s, the rotation speed of 180 r/min, the sugarcane cluster diameter of 3 cm, and the cutting inclination angle of 20°. Through bench test, it has been verified that the splitting rate of sugarcane stubble was 8.84%, and the damage rate of sugarcane stubble was less than 10%, met the sugarcane harvest standards.Practical ApplicationsThe cutting quality of sugarcane stubble has a significant impact on the growth of sugarcane in the following year. Unsupported basecutting would often lead to stubble damage. The interaction relationship between the basecutter and stalk of unsupported basecutting and supported basecutting were analyzed based on theoretical analysis and simulation tests. By optimizing the kinematic and structure parameters of basecutter and analyzing the cutting performance of the basecutter, the stubble splitting rates under the supported basecutting mode was reduced. The research could provide a reference for parameter optimization and basecutting methods of the sugarcane harvester.

High-level production of poly-γ-glutamic acid by a newly isolated Bacillus sp. YJY-8 and potential use in increasing the production of tomato

Strain YJY-8, a new γ-polyglutamic acid producer, was separated from fermented soybean paste samples. The strain was identified as a genus of Bacillus by morphological and 16S rDNA sequence analysis and was named Bacillus sp. YJY-8. The optimal medium composition and cultural conditions were studied using a single-factor experiment and a response surface experiment. The optimized medium consisted of monosodium glutamate 70 g/L, glucose 54.3 g/L, glycerol 31.8 g/L, ammonium sulfate 11.1 g/L, yeast extract 3.2 g/L, tryptone 1.5 g/L, L-glutamic acid 6.8 g/L, MgSO4 7H2O 0.5 g/L, FeCl3 6H2O 0.02 g/L, KH2PO4 0.9 g/L, CaCl2 0.03 g/L, MnSO4 H2O 0.3 g/L, ammonium molybdate 0.02 g/L, pH 7.0. The optimal cultivation conditions were 35 °C and pH 7.0. Under the optimized conditions, after 48 hr of cultivation, the highest shaking flask fermentation level of γ-PGA reached 65.2 ± 0.36 g/L. In addition, through fed-batch fermentation in 30 L fermenters, the fermentation level of γ-PGA reached its highest level at 88.42 g/L and productivity was 1.23 g/(L hr) after 72 hr. Then, the effect of γ-PGA on tomato yield was investigated. At the seedling stage, the plant height and stem diameter of γ-PGA treated plants increased by 5.69 and 15.735% after spraying γ-PGA for 19 days. During the flowering and fruiting period, the stem diameter of the γ-PGA treatment group increased by 6.74%, with a maximum increase of 11.65%. The number of fruit branches increased by 0.56–16.29% and the number of fruit sets increased by 1.01–28.47%. At the fruit maturation stage, the yield of tomatoes increased by 10.51, 14.27, and 5.83%.

Optimum carbonization of Kevlar fabric for electromagnetic interference shielding applications

The study involved single-stage carbonization and physical activation of Kevlar woven fabric to convert into activated carbon fabric. The carbonization process was optimised for high carbon yield and low electrical resistivity of activated carbon fabric using Box-Behnken experimental design and response surface methodology. The three process parameters namely charcoal amount, gas flow rate, and carbonization temperature were selected. The empirical equations obtained through response surface methodology for carbon yield and electrical resistivity were found in good agreement with the experimental values. An optimum amount of charcoal, optimum nitrogen flowrate, and low carbonization temperature was found suitable for higher carbon yield. On the other hand, high charcoal amount, high carbonization temperature, and optimum nitrogen flow rate resulted in low electrical resistivity of activated carbon fabric. Later, the activated carbon fabrics were prepared under the optimum carbonization conditions to get high carbon yield and low electrical resistivity. The optimized sample for electrical resistivity showed higher electromagnetic interference (EMI) shielding properties at lower as well as higher frequencies due to its highly porous morphology and electrical conductivity.

Highly sensitive and selective electrochemical sensor for simultaneous determination of gallic acid, theophylline and caffeine using poly(l-proline) decorated carbon nanotubes in biological and food samples

In this work, a novel, simple and reproducible poly(l-proline)/functionalized multi-walled carbon nanotube composite on glassy carbon electrode (poly(PRO)-MWCNTs/GCE) was developed as an electrochemical sensor for the simultaneous determination of gallic acid (GA), theophylline (TP) and caffeine (CAF) by differential pulse voltammetry (DPV).The sensing platform was optimized by experimental design and response surface methodology, using various factors affecting polymerization and detection, such as electropolymerization time and potential, and pH, respectively. As a result, the dispersion conditions were the mixing of 1.78 mg MWCNTs with 1.00 mL l-proline solution to 4.14 mg mL−1 (in SDBS 0.5%), followed by 21 min of sonication with electropolymerization by 16 cyclic scans. In addition, the final analysis was performed at a pH of 3.00 and prior accumulation at 0.350 V for 40 s.The electrochemical behavior of GA, TP and CAF on the optimized sensor was investigated. As a result, the electrode preserves and synergistically combines the properties of each modifier. This new electrochemical sensor showed superior electrocatalytic properties for the oxidation of GA, TP and CAF, which significantly improved the sensitivity of the three compounds.Under the optimized experimental conditions, the detection limits achieved by S/N were 0.03, 0.04 and 0.11 μmol L−1 for GA, TP and CAF, respectively. The analysis of real samples was successfully performed in human breast milk, tea, infusion of yerba mate, coffee, Coca-Cola zero and energy drink, showing good recoveries, ranged between 87 and 108%. The proposed sensor also showed good selectivity, repeatability and reproducibility, indicating feasibility and reliability.This is the first time that the l-proline monomer is used as a dispersant for MWCNTs and as a precursor for the in-situ polymerization of the proline polymer. Previously, the electropolymerizations were carried out with the monomer in solution rather than as an exfoliant of MWCNTs, where the polymer is electrosynthesized between MWCNTs rather than on them. In this way, the large specific surface area and strong adsorption ability of the nanomaterial are enhanced, and the ability to promote electron transfer reaction is increased, which provides enough effective reaction sites.

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.

Experimental analysis and response surface optimization of the influence of Zn/Al mass ratio on the creep resistance and tensile properties of As-cast Mg-Zn-Al alloy

Mg-Zn-Al (ZA) alloys are intended to exhibit creep resistance and high temperature mechanical capabilities due to appropriate Zn/Al mass ratio control. The effect of altering Al concentration (1, 2, 3, 4, 5, 6) on the tensile and creep resistance properties of Mg-9Zn-xAl alloy was determined experimentally and quantitatively optimized using response surface method (RSM). It was observed that 2 wt% Al improves both room and elevated temperature tensile strength, and ductility of the considered ZA alloy. The creep rate sharply increased when the mass fraction of aluminum rose above 4 wt%. For the purpose of forecasting the tensile and creep properties of the ZA alloy at any given aluminum mass percentage, quartic models were generated, with all model terms significant. Strong room and high-temperature tensile strength, %elongation, and creep resistance were all reached in the low Al-containing ZA alloys, with 1.597 wt% anticipated ideal Al mass concentration, according to RSM optimization.

Effects of WEDM and AWJ cutting methods on induction motor efficiency and total magnetic losses: Experimental design and response surface methodology

In this study, the effect of cutting electrical steel laminations using abrasive water jet (AWJ) and wire electrical discharge machining (WEDM) techniques on 5.5 kW induction motor efficiency (MEfficiency) and total magnetic losses (TLosses) was investigated. After the stator and rotor packages were formed, winding, varnishing and mechanical assembly processes were carried out and the motors were prepared for MEfficiency and TLosses tests according to the IEC 60034-2-1-1A standard. Tests were performed using different frequencies (f) and motor loading rates (MLoad). While burr formation was observed with the effect of plastic deformation on the cutting edge of electrical steels with AWJ, recast layer formation was observed with the effect of heat in WEDM. MEfficiency decreased while TLosses increased due to increasing f and MLoad in both cutting methods. Maximum MEfficiency and minimum TLosses values were measured in WEDM, it was determined that optimum results using Response Surface Methodology (RSM) were measured at f of 50 Hz and MLoad of 100% values in both cutting methods. The statistical effects of f and MLoad on MEfficiency and TLosses were revealed with ANOVA (Analysis of variance). In addition, mathematical models were developed for the prediction of MEfficiency and TLosses.

Study on the Relationship between Process Parameters and theFormation of GTAW Additive Manufacturing of TC4 Titanium Alloy Using the Response Surface Method

The geometric parameters of the deposited layer include the width, height, and penetration depth of the deposited layer. The welding current, wire feeding speed, and torch travel speed during the additive manufacturing process of TC4 titanium alloy have the greatest impact on the geometric parameters of the deposited layer. In order to study how the deposition layer width, deposition layer height, and penetration depth are affected by the welding current, wire feeding speed, and torch travel speed, this article uses Design Expert 8.0.6 software for Box−Behnken design response surface experiments. During the experimental design, the welding current, wire feeding speed, and torch travel speed are used as input variables. The deposition layer width, deposition layer height, and penetration depth are selected as the responses. We designed 17 response surface experiments that were conducted using GTAW-AM. The results show that as the welding current increases, the penetration depth and width of deposition layer gradually increase, and the deposition layer height gradually decreases. As the wire feeding speed increases, the deposition layer height and penetration depth gradually increase, and the wire feeding speed has a minimal effect on the deposition layer width. As the torch travel speed increases, the penetration depth, width and height of deposition layer gradually decrease. The response surface method experimental design can also optimize the matching of three process parameters: welding current, wire feeding speed, and torch travel speed, thereby obtaining the optimal matching range of process parameters. Within the optimized matching range of process parameters, a welding current of 90 A, a wire feeding speed of 900 mm/min, and a torch travel speed of 200.18 mm/min were selected to prepare TC4 titanium alloy thin-walled part. The microstructure of the top, middle and bottom are all basketweave structure. The α phase gradually becomes coarse from the top to the bottom. The microhardness of the top, middle, and bottom of the thin-walled parts is 362.7 HV, 352.7 HV, and 340.5 HV, respectively. The horizontal tensile strength is 926.1 MPa, with an elongation of 12.22%, and the vertical tensile strength is 938.1 MPa, with an elongation of 14.41%.

Statistical optimization of process variables for agarase production using Microbacterium sp. SS5 strain from non-marine sources

Agar oligosaccharides are thought to be valuable biomolecules with high bioactivity potential, along with a wide range of applications and advantages. The current study aimed to optimize the culture parameters required to produce agarase enzyme and agar oligosaccharides from industrial waste agar. Microbacterium spp. strain SS5 was isolated from a non-marine source and could synthesize oligo derivatives for use in a variety of industries ranging from food to pharmaceuticals. In addition, the strain and culture conditions were optimized to maximize extracellular agarase production. The bacterium grew best at pH 5.0 − 9.0, with an optimal pH of 7.5 − 8.0; temperatures ranging from 25 to 45 °C, with an optimal of 35 °C; and carbon and nitrogen concentrations of 0.5% each. Plackett-Burman experimental design and response surface methods were used to optimize various process parameters for agarase production by Microbacterium spp. strain SS5. Using the Plackett-Burman experimental design, eleven process factors were screened, and agar, beef extract, CaCl2, and beginning pH were found as the most significant independent variables affecting agarase production with confidence levels above 90%. To determine the optimal concentrations of the identified process factors on agarase production, the Box- Behnken design was used. Agarase production by Microbacterium spp. strain SS5 after optimization was 0.272 U/mL, which was determined to be greater than the result obtained from the basal medium (0.132 U/mL) before screening using Plackett-Burman and BBD with a fold increase of 2.06.