Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase variations.The present study investigated...Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase variations.The present study investigated the impact of parameters in slurry preparation and heat treatment on the yield strength and ductility of T6 heat-treated A356 Al-Si alloy using rapid slurry forming(RSF)semi-solid casting.The focus was primarily on the robustness of mechanical properties based on Taguchi design method.By analyzing signal-to-noise ratio and minimum value calculated from-3S,the optimum slurry preparation parameters and heat treatment parameters were determined to be no quench,enthalpy exchange material(EEM)temperature of 140℃,EEM-to-melt ratio of 6mass%,stirring time of 18 s,solution heat treated at 520℃ for 2 h,and ageing heat treated at 190℃ for 6 h.In a small batch validation,the-3S yield strength and-3S elongation reach 256.1 MPa and 5.03% respectively,showing a satisfactory robustness.The hardness and microstructure of heat-treated samples with the best and worst properties were characterized to gain insight into the underlying mechanisms affecting the mean value and variations of mechanical properties.展开更多
One of the nontraditional manufacturing processes is the chemical machining that deals with the removal of material substances using acidic or alkaline chemical solutions. This study aimed to determine the maximum mat...One of the nontraditional manufacturing processes is the chemical machining that deals with the removal of material substances using acidic or alkaline chemical solutions. This study aimed to determine the maximum material removal rate(MRR), and minimum surface roughness(SRa) of Ti-5Al-2.5Sn alloy during chemical milling that is possible to achieve by varying the etching chemical milling parameters in terms of time, concentration of the chemical solution [hydrofluoric acid(HF) and nitric acid(HNO_(3))], and chemical milling temperature. The Taguchi method based on a statistical design of experiments(DOE) technique with an L_(16) orthogonal array is efficiently used to obtain the objective of this study and to detect optimal chemical milling parameters for the Ti-5Al-2.5Sn alloy. The experimental results were analyzed using ANOVA analysis to determine the importance of each system parameter on the response variables(MRR and SRa). The optimal process parameters were found to be at a chemical solution concentration of 22.5% HF and 17% HNO_(3), a temperature of 45 ℃, and a time of 60 min. These parameters resulted in a maximum MRR of 0.0842 mg/min and a minimum SRa of 0.30 μm. The ANOVA result signalized that the concentration of the etching acids has the most impact on both responses with contribution percentages of 81% and 67% respectively. This takes a look at the efficacy of the Taguchi technique in optimizing chemical milling procedures and offers precious insights for selecting process parameters to attain favored results.展开更多
DOE （design of experiments） is a systematic, rigorous approach to engineering problem-solving that applies principles and techniques at the data collection stage so as to ensure the generation of valid, defensible, ...DOE （design of experiments） is a systematic, rigorous approach to engineering problem-solving that applies principles and techniques at the data collection stage so as to ensure the generation of valid, defensible, and supportable engineering conclusions. This paper presents a comparison of three different experimental designs （full experimental design, fractional design and Taguchi design） aimed at studying the effects of cutting parameters variations on surface finish. The results revealed that the effects obtained by analyzing both fractional and Taguchi designs were comparable to the main effects and two-level interactions obtained by the full factorial design. Thus, we conclude that full factorial design appear to be reliable and more economical since they permit to reduce by a factor the amount of time and effort required to conduct the experimental design without losing valuable information. Thus, we conclude that full factorial design appear to be reliable and more economical and without losing valuable information.展开更多
In this investigation, the effect of formulation variables on the release properties of timed- release press-coated tablets was studied using the Taguchi method of experimental design. Formulations were prepared based...In this investigation, the effect of formulation variables on the release properties of timed- release press-coated tablets was studied using the Taguchi method of experimental design. Formulations were prepared based on Taguchi orthogonal array design with different types of hydrophilic polymers (X1), varying hydrophilic polymer/ethyl cellulose ratio (X2), and addition of magnesium stearate (X3) as independent variables. The design was quantitatively evalu-ated by best fit mathematical model. The results from the statistical analysis revealed that factor X1, X3 and interaction factors between X1X2 and X1X3 were found to be significant on the re-sponse lag time (Y1), where as only factor X1 was found to be significant on the response percent drug release at 8 hrs (Y2). A numerical optimization technique by desirability function was used to optimize the response variables, each having a different target. Based on the re-sults of optimization study, HPC was identified as the most suitable hydrophilic polymer and incorporation of hydrophobic agent magnesium stearate, could significantly improve the lag time of the timed-release press-coated tablet.展开更多
This paper proposes a novel robust design method for the sense mode of a MEMS vibratory gyroscope based on fuzzy reliability and Taguchi design. The principles of fuzzy reliability and Taguchi design are both introduc...This paper proposes a novel robust design method for the sense mode of a MEMS vibratory gyroscope based on fuzzy reliability and Taguchi design. The principles of fuzzy reliability and Taguchi design are both introduced and described in detail. Experimental results demonstrate that the signal to noise ratio of the robust design scheme is better than those of the other experimental schemes.Over the full temperature range from -40 to 80°C, the temperature sensitivities of phase margin, gain margin, sensitivity margin,the maximum amplitude of open loop system, bandwidth of closed loop system, and the performance function of the robust design system are all smaller than those of the original design system. Meanwhile, the temperature sensitivity of the bandwidth of the robust design system is improved to 126 from 1075 ppm/°C. Moreover, the bias drift over the full temperature range of the robust design system is improved to 61°/h from 179°/h.展开更多
The optimum drying conditions with regard to minimum color changes, high rehydration ratio and drying rate for chanterelle mushrooms is inadequately known. To address this problem, drying kinetics for chanterelle mush...The optimum drying conditions with regard to minimum color changes, high rehydration ratio and drying rate for chanterelle mushrooms is inadequately known. To address this problem, drying kinetics for chanterelle mushroom samples with sizes of 20 mm×20 mm×20 mm cube, 20 mm×20 mm×30 mm cuboid, and Ø40 mm×20 mm cylindrical shape were experimented. Drying air temperatures of 40℃, 48℃, and 56℃ at superfluous humidity and velocity of 2.2 m/s were used. Initial color pixels for each sample were determined using Note 8 Pro Xiaomi smartphone camera and image processing tool in Matlab R2019a. Triplicate experimentation was done based on L9 Taguchi orthogonal arrays with drying rate, specific moisture extraction rate, color change, and rehydration ratio being the response parameters. The drying rate increased from 1.1174 g/g∙min to 1.3478 g/g.min as the temperature rose from 40℃ to 56℃. The mushroom cube had the highest drying rate of 1.2860 g/g∙min while the cylindrical shape had the lowest rate of 1.1764 g/g∙min. Similarly, SMER increased from 0.006 326to 0.013 27 g/kWh with the temperature rise. Contrary, SMER decreased from 0.006 92 to 0.013 63 g/kWh in cylinder to cube respectively. Color change was highest at 40℃ (13.49) and lowest at 56℃ (11.94). The mushroom cube had the lowest color change of 9.28 on average when compared to other shapes. Rehydration ratio was highest at 56℃ (3.824) as compared to 48℃ and 40℃. Additionally, the mushroom cube had the highest rehydration ratio of 4.55 on average as compared to other shapes. Temperature variation significantly influenced the drying rate and SMER. However, temperature variation had insignificant differences in color change and rehydration ratio. Mushroom shape variation had a significant difference in all the response variables tested. Conclusively, mushroom cubes at the drying temperature of 56℃ gave optimized drying conditions for chanterelle mushrooms with minimal quality deviations. Thus, chanterelle mushrooms can be sliced into cubes to allow quick drying rate, better SMER, rehydration ratio, and have minimal color change.展开更多
Target assembly is a key consumable material for producing thin fi lm used in the electronic packaging and devices. The residual stresses induced during the process of soldering are detrimental to the performance of t...Target assembly is a key consumable material for producing thin fi lm used in the electronic packaging and devices. The residual stresses induced during the process of soldering are detrimental to the performance of target assembly. In this work, the intensity and distribution of the soldering residual stress of Co/In/Cu target assembly subjected to a 20 W/(m^2 K) cooling condition corresponding to the actual air cooling process were studied, based on fi nite element simulation and Taguchi method, to optimize the sputtering target assembly. Effects of different control factors, including solder material, thickness of solder layer, target and backing plate, on the soldering residual stress of target assembly are investigated. The maximum residual stress is calculated as 9.28 MPa in the target located at 0.16 mm from target–solder layer interface and at a distance of 0.78 mm from symmetry axis. The optimal design in target assembly has the combination of indium solder material, cobalt target at 12 mm thick, solder layer at 0.8 mm thick, copper backing plate at 15 mm thick. Moreover, solder material is the most important factor among control factors in the target assembly.展开更多
The gear transmission system has been widely applied in mechanical systems,and many high-performance applications of these systems require low weight.With the aid of establishing the optimization model of the gear tra...The gear transmission system has been widely applied in mechanical systems,and many high-performance applications of these systems require low weight.With the aid of establishing the optimization model of the gear transmission system that consists of an objective function and some constraints(for example,the bending stress,the contact stress,the torsional strength,etc.),the optimal weight design of the gear transmission system can be transformed into the optimization problem for the objective function under the constraints.Moreover,both the shaft and the gear of the gear transmission system are considered simultaneously in our design.The hybrid Taguchi-genetic algorithm(HTGA)is employed to find the optimal design variables and the optimal weight of the system.An illustrated example for the single spur gear reducer is given to show that the optimal weight design problem can be successfully solved using the proposed design scheme.It also proves the high efficiency and feasibility of the algorithm in the gear design.展开更多
Different Ziegler-Natta catalysts were employed to polymerize ethylene. To investigate the influences of reaction parameters, namely Al/Ti molar ratio, hydrogen and processing parameters, i.e. ethylene pressure and te...Different Ziegler-Natta catalysts were employed to polymerize ethylene. To investigate the influences of reaction parameters, namely Al/Ti molar ratio, hydrogen and processing parameters, i.e. ethylene pressure and temperature, a Taguchi experimental design was worked out. An L27 orthogonal array was chosen to take the above-mentioned parameters and relevant interactions into account. Response surface method was the tool used to analyze the experimental design results. Al/Ti, ethylene pressure and temperature were selected as experimental design factors, and catalyst activity and polymerization yield were the response parameters. Increasing pressure, due to an increment in monomer accessibility, and rising Al/Ti, because of higher reduction in the catalysts, cause an increase in both polymerization yield and catalyst activity. Nonetheless, a higher temperature, thanks to reducing ethylene solubility in the slurry medium and partially catalyst destruction, lead to a reduction in both response parameters. A synergistic effect was also observed between temperature and pressure. All catalyst activities will reduce in the presence of hydrogen. Molecular weight also shows a decline in the presence of hydrogen as a transfer agent. However, the polydispersity index remains approximately intact. Using SEM, various morphologies, owing to different catalyst morphologies, were seen for the polyethylene.展开更多
The present study deals with the effects of both tin (Sn) and graphite (Gr) powders on the cold extrudability of Fe-TiC nanocomposites as lubricant. The production process includes low-energy ball milling, powder meta...The present study deals with the effects of both tin (Sn) and graphite (Gr) powders on the cold extrudability of Fe-TiC nanocomposites as lubricant. The production process includes low-energy ball milling, powder metallurgy and cold direct Extrusion. Due to various factors influencing the extrudability of the Fe-TiC nanocomposites, such as milling time, rate of extrusion, type and content of lubricant and etc, Taguchi robust design method of system optimization was used to determine the approximate contribution percent (% ρ) of each factor. In order to investigation of Fe-TiC properties, samples with best quality of extrusion were analyzed by XRD and SEM investigations. The results indicate that, sitting the atomic layers of Sn lubricant between Fe and TiC particles leads to decreasing the friction. In this case sliding the particles on each other is easier and a part of the load is applied on lubricant. The results of extrusion of samples indicate that using 2% Sn admixed and die wall graphite lubrication can improve cold extrudability of Fe-TiC nanocomposites.展开更多
Paper and pulp mills generate substantial volumes of wastewater containing lignin-derived compounds that are challenging to degrade using conventional wastewater treatment methods.This study presents a novel biofilm-b...Paper and pulp mills generate substantial volumes of wastewater containing lignin-derived compounds that are challenging to degrade using conventional wastewater treatment methods.This study presents a novel biofilm-based process for enhanced lignin removal in wastewater using the fungus Neurospora discreta,which effectively degrades lignin and forms robust biofilms at the air–liquid interface under specific conditions.The process was optimised using the Taguchi design of experiments approach,and three factors including pH,copper sulphate concentration,and trace element concentration were evaluated at three levels.Experimental data were analysed against three responses:lignin degradation efficiency and the activities of two ligninolytic enzymes(polyphenol oxidase and versatile peroxidase).The results indicated that wastewater pH was the most significant parameter affecting lignin degradation efficiency and enzyme activities.Over 70%lignin degradation was achieved at pH levels of 5 and 6 with copper sulphate concentrations above 4 mg/L,while degradation efficiency drastically dropped to 45%at a pH value of 7.Reversed-phase high-performance liquid chromatography analysis demonstrated the effects of the three factors on the polar and non-polar components of lignin in wastewater,revealing a clear decrease in all peak areas after treatment.Additionally,significant relationships were observed between biofilm properties(including porosity,water retention value,polysaccharide content,and protein content)and lignin removal efficiency.This study also reported for the first time the presence of versatile peroxidase,a ligninolytic enzyme,in Neurospora sp.展开更多
文摘Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase variations.The present study investigated the impact of parameters in slurry preparation and heat treatment on the yield strength and ductility of T6 heat-treated A356 Al-Si alloy using rapid slurry forming(RSF)semi-solid casting.The focus was primarily on the robustness of mechanical properties based on Taguchi design method.By analyzing signal-to-noise ratio and minimum value calculated from-3S,the optimum slurry preparation parameters and heat treatment parameters were determined to be no quench,enthalpy exchange material(EEM)temperature of 140℃,EEM-to-melt ratio of 6mass%,stirring time of 18 s,solution heat treated at 520℃ for 2 h,and ageing heat treated at 190℃ for 6 h.In a small batch validation,the-3S yield strength and-3S elongation reach 256.1 MPa and 5.03% respectively,showing a satisfactory robustness.The hardness and microstructure of heat-treated samples with the best and worst properties were characterized to gain insight into the underlying mechanisms affecting the mean value and variations of mechanical properties.
文摘One of the nontraditional manufacturing processes is the chemical machining that deals with the removal of material substances using acidic or alkaline chemical solutions. This study aimed to determine the maximum material removal rate(MRR), and minimum surface roughness(SRa) of Ti-5Al-2.5Sn alloy during chemical milling that is possible to achieve by varying the etching chemical milling parameters in terms of time, concentration of the chemical solution [hydrofluoric acid(HF) and nitric acid(HNO_(3))], and chemical milling temperature. The Taguchi method based on a statistical design of experiments(DOE) technique with an L_(16) orthogonal array is efficiently used to obtain the objective of this study and to detect optimal chemical milling parameters for the Ti-5Al-2.5Sn alloy. The experimental results were analyzed using ANOVA analysis to determine the importance of each system parameter on the response variables(MRR and SRa). The optimal process parameters were found to be at a chemical solution concentration of 22.5% HF and 17% HNO_(3), a temperature of 45 ℃, and a time of 60 min. These parameters resulted in a maximum MRR of 0.0842 mg/min and a minimum SRa of 0.30 μm. The ANOVA result signalized that the concentration of the etching acids has the most impact on both responses with contribution percentages of 81% and 67% respectively. This takes a look at the efficacy of the Taguchi technique in optimizing chemical milling procedures and offers precious insights for selecting process parameters to attain favored results.
文摘DOE （design of experiments） is a systematic, rigorous approach to engineering problem-solving that applies principles and techniques at the data collection stage so as to ensure the generation of valid, defensible, and supportable engineering conclusions. This paper presents a comparison of three different experimental designs （full experimental design, fractional design and Taguchi design） aimed at studying the effects of cutting parameters variations on surface finish. The results revealed that the effects obtained by analyzing both fractional and Taguchi designs were comparable to the main effects and two-level interactions obtained by the full factorial design. Thus, we conclude that full factorial design appear to be reliable and more economical since they permit to reduce by a factor the amount of time and effort required to conduct the experimental design without losing valuable information. Thus, we conclude that full factorial design appear to be reliable and more economical and without losing valuable information.
文摘In this investigation, the effect of formulation variables on the release properties of timed- release press-coated tablets was studied using the Taguchi method of experimental design. Formulations were prepared based on Taguchi orthogonal array design with different types of hydrophilic polymers (X1), varying hydrophilic polymer/ethyl cellulose ratio (X2), and addition of magnesium stearate (X3) as independent variables. The design was quantitatively evalu-ated by best fit mathematical model. The results from the statistical analysis revealed that factor X1, X3 and interaction factors between X1X2 and X1X3 were found to be significant on the re-sponse lag time (Y1), where as only factor X1 was found to be significant on the response percent drug release at 8 hrs (Y2). A numerical optimization technique by desirability function was used to optimize the response variables, each having a different target. Based on the re-sults of optimization study, HPC was identified as the most suitable hydrophilic polymer and incorporation of hydrophobic agent magnesium stearate, could significantly improve the lag time of the timed-release press-coated tablet.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61434003 & 51505089)
文摘This paper proposes a novel robust design method for the sense mode of a MEMS vibratory gyroscope based on fuzzy reliability and Taguchi design. The principles of fuzzy reliability and Taguchi design are both introduced and described in detail. Experimental results demonstrate that the signal to noise ratio of the robust design scheme is better than those of the other experimental schemes.Over the full temperature range from -40 to 80°C, the temperature sensitivities of phase margin, gain margin, sensitivity margin,the maximum amplitude of open loop system, bandwidth of closed loop system, and the performance function of the robust design system are all smaller than those of the original design system. Meanwhile, the temperature sensitivity of the bandwidth of the robust design system is improved to 126 from 1075 ppm/°C. Moreover, the bias drift over the full temperature range of the robust design system is improved to 61°/h from 179°/h.
基金supported by the Jiangsu Special Fund for Innovation and Extension of Agricultural Science and Technology (Project No.NJ2019-15)for supporting this research.
文摘The optimum drying conditions with regard to minimum color changes, high rehydration ratio and drying rate for chanterelle mushrooms is inadequately known. To address this problem, drying kinetics for chanterelle mushroom samples with sizes of 20 mm×20 mm×20 mm cube, 20 mm×20 mm×30 mm cuboid, and Ø40 mm×20 mm cylindrical shape were experimented. Drying air temperatures of 40℃, 48℃, and 56℃ at superfluous humidity and velocity of 2.2 m/s were used. Initial color pixels for each sample were determined using Note 8 Pro Xiaomi smartphone camera and image processing tool in Matlab R2019a. Triplicate experimentation was done based on L9 Taguchi orthogonal arrays with drying rate, specific moisture extraction rate, color change, and rehydration ratio being the response parameters. The drying rate increased from 1.1174 g/g∙min to 1.3478 g/g.min as the temperature rose from 40℃ to 56℃. The mushroom cube had the highest drying rate of 1.2860 g/g∙min while the cylindrical shape had the lowest rate of 1.1764 g/g∙min. Similarly, SMER increased from 0.006 326to 0.013 27 g/kWh with the temperature rise. Contrary, SMER decreased from 0.006 92 to 0.013 63 g/kWh in cylinder to cube respectively. Color change was highest at 40℃ (13.49) and lowest at 56℃ (11.94). The mushroom cube had the lowest color change of 9.28 on average when compared to other shapes. Rehydration ratio was highest at 56℃ (3.824) as compared to 48℃ and 40℃. Additionally, the mushroom cube had the highest rehydration ratio of 4.55 on average as compared to other shapes. Temperature variation significantly influenced the drying rate and SMER. However, temperature variation had insignificant differences in color change and rehydration ratio. Mushroom shape variation had a significant difference in all the response variables tested. Conclusively, mushroom cubes at the drying temperature of 56℃ gave optimized drying conditions for chanterelle mushrooms with minimal quality deviations. Thus, chanterelle mushrooms can be sliced into cubes to allow quick drying rate, better SMER, rehydration ratio, and have minimal color change.
基金supported financially by the National Key R&D Program of China (No. 2017YFB0305501)the National Natural Science Foundation of China (No. 51475220)the China Postdoctoral Science Foundation Funded Project (No. 2016M591464)
文摘Target assembly is a key consumable material for producing thin fi lm used in the electronic packaging and devices. The residual stresses induced during the process of soldering are detrimental to the performance of target assembly. In this work, the intensity and distribution of the soldering residual stress of Co/In/Cu target assembly subjected to a 20 W/(m^2 K) cooling condition corresponding to the actual air cooling process were studied, based on fi nite element simulation and Taguchi method, to optimize the sputtering target assembly. Effects of different control factors, including solder material, thickness of solder layer, target and backing plate, on the soldering residual stress of target assembly are investigated. The maximum residual stress is calculated as 9.28 MPa in the target located at 0.16 mm from target–solder layer interface and at a distance of 0.78 mm from symmetry axis. The optimal design in target assembly has the combination of indium solder material, cobalt target at 12 mm thick, solder layer at 0.8 mm thick, copper backing plate at 15 mm thick. Moreover, solder material is the most important factor among control factors in the target assembly.
基金Supported by the Fundamental Research Funds for the Central Universities(20102080201000085)the National Natural Science Foundation of China(50875189)
文摘The gear transmission system has been widely applied in mechanical systems,and many high-performance applications of these systems require low weight.With the aid of establishing the optimization model of the gear transmission system that consists of an objective function and some constraints(for example,the bending stress,the contact stress,the torsional strength,etc.),the optimal weight design of the gear transmission system can be transformed into the optimization problem for the objective function under the constraints.Moreover,both the shaft and the gear of the gear transmission system are considered simultaneously in our design.The hybrid Taguchi-genetic algorithm(HTGA)is employed to find the optimal design variables and the optimal weight of the system.An illustrated example for the single spur gear reducer is given to show that the optimal weight design problem can be successfully solved using the proposed design scheme.It also proves the high efficiency and feasibility of the algorithm in the gear design.
文摘Different Ziegler-Natta catalysts were employed to polymerize ethylene. To investigate the influences of reaction parameters, namely Al/Ti molar ratio, hydrogen and processing parameters, i.e. ethylene pressure and temperature, a Taguchi experimental design was worked out. An L27 orthogonal array was chosen to take the above-mentioned parameters and relevant interactions into account. Response surface method was the tool used to analyze the experimental design results. Al/Ti, ethylene pressure and temperature were selected as experimental design factors, and catalyst activity and polymerization yield were the response parameters. Increasing pressure, due to an increment in monomer accessibility, and rising Al/Ti, because of higher reduction in the catalysts, cause an increase in both polymerization yield and catalyst activity. Nonetheless, a higher temperature, thanks to reducing ethylene solubility in the slurry medium and partially catalyst destruction, lead to a reduction in both response parameters. A synergistic effect was also observed between temperature and pressure. All catalyst activities will reduce in the presence of hydrogen. Molecular weight also shows a decline in the presence of hydrogen as a transfer agent. However, the polydispersity index remains approximately intact. Using SEM, various morphologies, owing to different catalyst morphologies, were seen for the polyethylene.
文摘The present study deals with the effects of both tin (Sn) and graphite (Gr) powders on the cold extrudability of Fe-TiC nanocomposites as lubricant. The production process includes low-energy ball milling, powder metallurgy and cold direct Extrusion. Due to various factors influencing the extrudability of the Fe-TiC nanocomposites, such as milling time, rate of extrusion, type and content of lubricant and etc, Taguchi robust design method of system optimization was used to determine the approximate contribution percent (% ρ) of each factor. In order to investigation of Fe-TiC properties, samples with best quality of extrusion were analyzed by XRD and SEM investigations. The results indicate that, sitting the atomic layers of Sn lubricant between Fe and TiC particles leads to decreasing the friction. In this case sliding the particles on each other is easier and a part of the load is applied on lubricant. The results of extrusion of samples indicate that using 2% Sn admixed and die wall graphite lubrication can improve cold extrudability of Fe-TiC nanocomposites.
基金supported by the Leverhulme Trust Research Project(Grant No.RPG-2020-021).
文摘Paper and pulp mills generate substantial volumes of wastewater containing lignin-derived compounds that are challenging to degrade using conventional wastewater treatment methods.This study presents a novel biofilm-based process for enhanced lignin removal in wastewater using the fungus Neurospora discreta,which effectively degrades lignin and forms robust biofilms at the air–liquid interface under specific conditions.The process was optimised using the Taguchi design of experiments approach,and three factors including pH,copper sulphate concentration,and trace element concentration were evaluated at three levels.Experimental data were analysed against three responses:lignin degradation efficiency and the activities of two ligninolytic enzymes(polyphenol oxidase and versatile peroxidase).The results indicated that wastewater pH was the most significant parameter affecting lignin degradation efficiency and enzyme activities.Over 70%lignin degradation was achieved at pH levels of 5 and 6 with copper sulphate concentrations above 4 mg/L,while degradation efficiency drastically dropped to 45%at a pH value of 7.Reversed-phase high-performance liquid chromatography analysis demonstrated the effects of the three factors on the polar and non-polar components of lignin in wastewater,revealing a clear decrease in all peak areas after treatment.Additionally,significant relationships were observed between biofilm properties(including porosity,water retention value,polysaccharide content,and protein content)and lignin removal efficiency.This study also reported for the first time the presence of versatile peroxidase,a ligninolytic enzyme,in Neurospora sp.
