For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the proc...For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the process and results in a mathematical description of the process behavior as a simple function based on the most important process factors can help to achieve higher production efficiency and quality.The present study aims at characterizing a well-known industrial process,the transesterification reaction of rapeseed oil with methanol to produce fatty acid methyl esters(FAME)for usage as biodiesel in a continuous micro reactor set-up.To this end,a design of experiment approach is applied,where the effects of two process factors,the molar ratio and the total flow rate of the reactants,are investigated.The optimized process target response is the FAME mass fraction in the purified nonpolar phase of the product as a measure of reaction yield.The quantification is performed using attenuated total reflection infrared spectroscopy in combination with partial least squares regression.The data retrieved during the conduction of the DoE experimental plan were used for statistical analysis.A non-linear model indicating a synergistic interaction between the studied factors describes the reactor behavior with a high coefficient of determination(R^(2))of 0.9608.Thus,we applied a PAT approach to generate further insight into this established industrial process.展开更多
Identification of process parameters,their effects and contributions to the outcomes of the system using experimental approach could be a daunting,time consuming,and costly course.Using proper statistical methods,i.e....Identification of process parameters,their effects and contributions to the outcomes of the system using experimental approach could be a daunting,time consuming,and costly course.Using proper statistical methods,i.e.,Taguchi method,could significantly reduce the number of required experiments and statistical significance of the parameter can be identified.Friction stir welding is one of those welding techniques with many parameters which have different effects on the quality of the welds.In friction stir welding the tool rotational speed(RPM)and transverse speed(mm/min)influence the strength(i.e.,hardness distribution)of the stirred zone.In this study,these two factors are investigated to determine the effect they will have on the hardness in the stirred zone of the friction stir welds and how the two factors are related to one another for as-cast magnesium alloy AM60 with nominal chemical composition of Mg-(5.5-6.5)Al-(0.24-0.6)Mn-0.22Zn-0.1Si.Experimental data was taken at three different tool rotational speeds and three different transverse speeds.The data obtained was then analyzed using a 32 factorial design to find the contribution of these parameters.It was determined that both tool rotational speed and transverse speed possess significant effects on the stir zone hardness.Also,the interactions between the two factors were statistically assessed.展开更多
Experiment statistical method and genetic algorithms based optimization method are used to obtain the optimum differential gear ratio for heavy truck that provides best fuel consumption when changing the working condi...Experiment statistical method and genetic algorithms based optimization method are used to obtain the optimum differential gear ratio for heavy truck that provides best fuel consumption when changing the working condition that affects its torque and speed range. The aim of the study is to obtain the optimum differential gear ratio with fast and accurate optimization calculation without affecting drivability characteristics of the vehicle according to certain driving cycles that represent the new working conditions of the truck. The study is carried on a mining dump truck YT3621 with 9 forward shift manual transmission. Two loading conditions,no load and 40 t,and four on road real driving cycles have been discussed. The truck powertrain is modeled using GT-drive,and DOE-post processing tool of the GT-suite is used for DOE analysis and genetic algorithm optimization.展开更多
This work investigates the proportion of generated fines in a pilot-scale experiment using a belt conveyor and commercial fuel pellets.For this,a belt conveyor with a length of 3.1 m was used and operated at varying c...This work investigates the proportion of generated fines in a pilot-scale experiment using a belt conveyor and commercial fuel pellets.For this,a belt conveyor with a length of 3.1 m was used and operated at varying conditions:speeds,percentages of material loading on the belt,two combinations of the inclination angle of the belt and the falling height,and a different number of handling steps.We considered a design of experiments approach based on response surface methodology to investigate the effect of different conditions on the potential of fines generation.Moreover,a comparison between the results of the belt conveyor and three common benchmark experimental approaches(tumbling box,rotary impact tester,and mechanical compression test)was made.Results show that the number of handling steps and the combined effect of drop height and inclination angle directly affected the fines generation.However,the tested belt speed range and the level of loading were of lower significance.A polynomial quadratic model was derived based on the regression analysis and showed a high accuracy to predict the proportion of fines.Moreover,the tumbling box method showed good potential to predict the proportion of fines in a belt conveyor when transported several times.展开更多
Fused deposition modeling is one of the most adaptable additive production method as a result of the value-effectiveness and environment-friendly nature.However,FDM technique nevertheless possesses primary problems in...Fused deposition modeling is one of the most adaptable additive production method as a result of the value-effectiveness and environment-friendly nature.However,FDM technique nevertheless possesses primary problems in phrases of negative surface best due to including layer by using layer production method for the prototypes.It is acceptable to explore an efficient method for FDM elements to enhance the bad surface first-rate and dimensions precision.In the present research paper,an effort has been made to decorate the surface better and optimize the vital processing parameter of FDM based benchmark the use of vapor smoothing procedure(VSP).A comparative experimental take a look at has been completed by layout of experiments,Taguchi technique to analyse impact of input layout parameters at the floor finish of benchmark FDM parts.The outcomes of prevailing research display that VSP treatment improves the surface excellent of FDM components to micro stage with negligible dimensional variation.It is observed that improved floor excellent is observed in the 1,2,-Dichloroethane chemical at 90°component construct orientation,0.25 mm layer thickness,10%fill density and 90 sec Exposure times.展开更多
Automotive torque converters have recently been designed with an increasingly narrower profile for the purpose of achieving a smaller axial size and reducing weight. Design of experiment(DOE) and computational fluid d...Automotive torque converters have recently been designed with an increasingly narrower profile for the purpose of achieving a smaller axial size and reducing weight. Design of experiment(DOE) and computational fluid dynamics(CFD) techniques are applied to improve the performance of a flat torque converter. Four torque converters with different flatness ratios(0.204, 0.186, 0.172, and 0.158) are designed and simulated first to investigate the effects of flatness ratio on their overall performance, including efficiency, torque ratio, and impeller torque factor. The simulation results show that the overall performance tends to deteriorate as the flatness ratio decreases. Then a parametric study covering six geometric parameters, namely, inlet and outlet angles of impeller, turbine, and stator is carried out. The results demonstrate that the inlet and outlet angles play an important role in determining the performance characteristics of a torque converter. Furthermore, the relative importance of the six design parameters is investigated using DOE method for each response(stall torque ratio and peak efficiency). The turbine outlet angle is found to exert the greatest influence on both responses. After DOE analysis, an optimized design for the flat torque converter geometry is obtained. Compared to the conventional product, the width of the optimized flat torque converter torus is reduced by about 20% while the values of stall torque ratio and peak efficiency are only decreased by 0.4% and 1.7%, respectively.The proposed new optimization strategy based on DOE method together with desirability function approach can be used for performance enhancement in the design process of flat torque converters.展开更多
The concept of Quality by Design was demonstrated in the development of a stability-indicating assay and related substances method by HPLC for Dabigatran Etexilate Capsules dosage form. Method design, method evaluatio...The concept of Quality by Design was demonstrated in the development of a stability-indicating assay and related substances method by HPLC for Dabigatran Etexilate Capsules dosage form. Method design, method evaluation, method control and life cycle management were explained by systematic flow chart. Analytical Target Product profile was defined. The method was developed using the Inertsil ODS-3V, 150 mm × 4.6 mm, 5 μm column using the gradient program with ammonium formate buffer as mobile phase A and acetonitrile as mobile phase B. Risk assessment was performed as part of method evaluation. Design of experiment tools was used to optimize the chromatographic conditions. A two-level Full Factorial Design along with Face Centered Central Composite design augmentation was employed and statistical analysis of the experimental data uncovered the significant influential of chromatographic factors. The design space and the contour plot suggest that the current center point parameters can be further modified, resulting in better acceptability of the response parameters. The performance of the optimized method was validated according to current ICH guidelines. Dabigatran Etexilate Capsules was subjected to various stress conditions like oxidative, acid, base, hydrolytic, thermal, humidity, and photolytic degradations and evaluated chromatograms at 220 nm. The degradation products were well separated from each other and main peak, demonstrating the stability-indicating power of the method. One of the major degradant impurities, which are forming in neutral hydrolysis stress condition, is isolated and characterized by using analytical techniques like IR, LC-MS and NMR. Degradation pathway for Dabigatran Etexilate was proposed based on forced degradation data along with reaction mechanism.展开更多
The increasing use of lithium-ion cells in large-scale,long-term applications drives a need for design methods that considers aging and accurate state of health estimation.A common approach is to rely on an empirical ...The increasing use of lithium-ion cells in large-scale,long-term applications drives a need for design methods that considers aging and accurate state of health estimation.A common approach is to rely on an empirical or semiempirical aging model fit to experimental data to estimate the evolution of capacity and power fade.Because aging data are costly to collect,pack designers either use Design of Experiment(DOE)techniques to define a set of efficient tests,or use existing aging data to calibrate aging models.Given the increasing quantity of available aging data,the question arises:how can experimental aging campaigns be quickly compared?However,a methodology for the comparison of sets of aging experiments is not discussed in the literature.As a result,pack designers usually rely on intuition to select between multiple aging studies proposed by DOE techniques or in the literature.This work proposes metrics to quantitatively capture the alignment between a set of aging experiments and a target application.These metrics allow pack designers to quickly compare many sets of aging experiments to evaluate those which have tested conditions relevant to the application.Case studies are presented to illustrate the application of these metrics using aging campaign data from the literature.To validate these metrics,this work examines the relationship between these metric values and aging model validation error for calendar aging data for 18650 NMC battery cells.It is demonstrated that greater metric values correspond to reduced model error for an empirical capacity fade model.展开更多
The bonded-particle model(BPM)is commonly used in the numerical analysis of ore samples.To improve the accuracy of simulating the mechanical process of ore process of ore crushing in a crusher,the parameters of the BP...The bonded-particle model(BPM)is commonly used in the numerical analysis of ore samples.To improve the accuracy of simulating the mechanical process of ore process of ore crushing in a crusher,the parameters of the BPM for the ore must be calibrated.In this study,a calibration method was proposed for the scientific determination of the parameters of the BPM for ore undergoing uniaxial compression.First,physical tests and simulations were conducted to determine the mechanical response(uniaxial compressive strength and macroscopic stiffness)of ore during uniaxial compression.Then,the sensitivity of the mechanical response to the values of microscopic parameters was tested using a Plackett-Burman design.Next,the microscopic parameters with the greatest impact on the response were identified,and the range of parameters that met the target response was determined using a steepest ascent design;Second,a second-order model of the mechanical response was established using the sensitive parameters by combining a Box-Behnken design with response surface methodology to obtain the optimal BPM parameters.Simulation tests showed that the normal stiffness per unit area,critical shear stress,and bonded disk radius had significant effects on the uniaxial compressive strength(UCS)and macroscopic stiffness(MS).To verify the validity of the proposed calibration method,laboratory tests were conducted.The consistency of the simulation results with experimental results indicated that response surface methodology with the Plackett-Burman design,steepest ascent design,and Box-Behnken design can be an effective method for calibrating the BPM of ores.展开更多
In this paper, a square textured parallel slider is considered for a study to improve the hydrodynamic performance of moving parts. The numerical method is employed for the analysis of a square texture with different ...In this paper, a square textured parallel slider is considered for a study to improve the hydrodynamic performance of moving parts. The numerical method is employed for the analysis of a square texture with different bottom profiles:flat, triangle T1, triangle T2, and curved. The governing Reynolds equation is solved using a finite difference numerical discretization technique with the Gauss–Seidel iterative scheme. To obtain optimized process parameters, the response surface methodology-based central composite design along with grey relational analysis multi-objective optimization is used. The multi-objective responses are the load capacity and friction coefficient. The triangle T2 bottom profile yields the highest load capacity and the lowest friction coefficient compared to flat, triangle T1, and curved bottom profiles, of which the triangle T1 bottom profile yields the worst results. For the triangle T2 bottom profile, the flow speed is found to be the most significant process parameter, followed by the aspect ratio. Texture density is found to be the least significant parameter based on increasing the load capacity and decreasing the friction coefficient.展开更多
To explore the forming process and mechanism of the surface texture of laser micropits,this paper presents the thermal model of laser machining based on the Neumann boundary conditions and an investigation on the effe...To explore the forming process and mechanism of the surface texture of laser micropits,this paper presents the thermal model of laser machining based on the Neumann boundary conditions and an investigation on the effects of various parameters on the processing.The surface profile and quality of the formed micropits were analyzed using NanoFocus 3D equipment through a design of experiment(DOE).The results showed that more intense melting and splashing occurred with higher power density and narrower pulse widths.Moreover,the compressive stress is an important indicator of the damage effects,and the circumferential thermal stress is the primary factor influencing the diameter expansion.During the process of laser machining,not only did oxides such as CuO and ZnO generate,the energy distribution also tended to decrease gradually from region#1 to region#3 based on an energy dispersive spectrometer(EDS)analysis.The factors significantly affecting the surface quality of the micropit surface texture are the energy and pulse width.The relationship between taper angle and energy is appropriately linear.Research on the formation process and mechanism of the surface texture of laser micropits provides important guidance for precision machining.展开更多
To promote the pose accuracy performance of a spatial parallel kinematic Mechanism( PKM) in service,a workshop oriented tolerance synthesis method based on design of experiment( DOE) is proposed,which involves two con...To promote the pose accuracy performance of a spatial parallel kinematic Mechanism( PKM) in service,a workshop oriented tolerance synthesis method based on design of experiment( DOE) is proposed,which involves two consecutive stages. In the first stage of DOE,the tolerance factor sensitivities are obtained according to initial tolerance settings with the consideration of the current manufacturing capacity,and the second stage of DOE makes use of them to produce multiple tolerance allocations which can adapt to current manufacturing capacity. A tolerance synthesis procedure is developed and integrated in tolerance design system for PKM. Comparing the results with peer method,the validity and practicability of this method is verified.展开更多
This work investigates the reuse of natural(SCB)and minopropyltriethoxysilanemodifed(MSCB)sugarcane bagasse fbres in cementitious composites.ugarcane bagasse fbres are pre-used in the treatment of motor oil contaminat...This work investigates the reuse of natural(SCB)and minopropyltriethoxysilanemodifed(MSCB)sugarcane bagasse fbres in cementitious composites.ugarcane bagasse fbres are pre-used in the treatment of motor oil contaminated effluents.A full factorial design is used to identify the effects of fbre type(SCB and MSCB),fbre length(0.6 and 1.2 mm),fbre amount(1 and 2 wt%)and fbre condition(before and after oil filtration)on apparent density,water absorption,apparent porosity,ultra-pulse velocity,dynamic modulus,flexural strength and modulus.SCB fibres lead to increased apparent density compared to MSCB fibre reinforced composites.MSCB fibres contribute to reduce composite porosity,leading to higher mechanical properties.The smaller area of MSCB fibres promotes a larger amount of cementitious phase per unit volume,thus increasing the strength of the sample.Longer sugarcane fbres(1.2 mm)have a larger surface area,leading to a higher fibre concentration per unit volume,which increases water absorption.The amount of fibre has no significant effect on mechanical and physical responses.Composites made with 2 wt%0.6 mm long MSCB fibres achieve promising results for non-structural civil engineering applications.展开更多
Electrospun poly(vinylidene fluoride)(PVDF)nanofiber web has been widely utilized as a functional material in various flexible sensors and generators due to its high piezoelectricity,ease processability,and low cost.A...Electrospun poly(vinylidene fluoride)(PVDF)nanofiber web has been widely utilized as a functional material in various flexible sensors and generators due to its high piezoelectricity,ease processability,and low cost.Among all the crystalline phases of PVDF,β-phase is a key property for PVDF nano fiber web,because the con tent of β-phase is directly proporti onal to piezoelectric performa nee of PVDF nano fiber web.Herein,the impact of graphe ne con tent(GC),tip-to-collector dista nee(TCD),and rotational speed of collector(RSC),as well as their interactions on theβ-phase formation of PVDF nano fiber web is systematically investigated via design of experime ntal method.The fraction of each crystalline phase of PVDF nano fiber web is calculated by FTIR spectra,and the crystallinity is determined by XRD patterns.The influences of GC,TCD,and RSC on both β-phase fraction and crystallinity of PVDF nanofiber are analyzed using Minitab program.The results show that GC,TCD,and RSC all have significa nt effect on the β-phase content of PVDF nano fiber web,and GC is the most significant one.In addition,an optimal electrospinning condition(GC=1 wt%,TCD=4 cm,and RSC=2000 r·min^-1)to fabricate high 0-phase crystallinity of PVDF nanofiber web is drawn,under which the crystallinity can reach 41.7%.The contributions in this study could provide guidanee for future research on fabricating high performance PVDF nanofiber web based sensors or generators.展开更多
A comprehensive study of the tribological performance of the Al-Zn-Mg-Cu/Al2O3 composite and its matrix alloy is presented in this paper, with a specific emphasis to identify and model the applicable wear conditions w...A comprehensive study of the tribological performance of the Al-Zn-Mg-Cu/Al2O3 composite and its matrix alloy is presented in this paper, with a specific emphasis to identify and model the applicable wear conditions where the composite provides a minimum of 50% reduction in wear rate and 25% lowering of the friction coefficient. Two-body abrasion experiments following Taguchi L27 orthogonal design have been performed separately on alloy and composite materials, both prepared by the stir casting method. The influence of crucial control factors including silicon carbide (SiC) abrasive size, load, sliding distance, and velocity on the percentage variations of wear rates and friction coefficients between alloy and composite have been studied using the analysis of variance technique and full quadratic regression method. The dominant control factors are identified as abrasive size, load, and the interaction between abrasive size and load. This has been verified by establishing the influence of abrasive size and load on variations of wear mechanisms like microcutting, microploughing, and delamination, identified by means of in-depth characterization of worn surfaces and generated debris for both alloy and composite. The selection of applicable tribological condition for the composite has been accomplished by adopting the multi-response optimization technique based on combined desirability approach to obtain concurrent optimization of the percentage variations of wear rates and friction coefficients. Predictive models correlating the superiority of tribological performance of composite with abrasion conditions have been developed, and these are found to be accurate (errors <10%), as determined by confirmatory experiment.展开更多
A five-step method framework is proposed by combing improved value stream mapping with simulation and design of experiment(DOE) to design the lean system for engineer-to-order(ETO) manufacturing,and lean practice impl...A five-step method framework is proposed by combing improved value stream mapping with simulation and design of experiment(DOE) to design the lean system for engineer-to-order(ETO) manufacturing,and lean practice implementation path is decided.Meanwhile,a real company case like HAVC is taken to display the application of the framework.The results indicate that compared to supermarket Kanban,constant work in process(Conwip) has the broader applicability in ETO manufacturing and the critical business process,like purchasing of key parts,and has more significant effects on value stream performance.Therefore,it should have priority in lean practice implementation.展开更多
When optimizingwebpages in order to achieve the best conversion rate,the traditional approach is to isolate and analyze themseparately through a sequence of experiments.In thispaper,wepropose a new framework to study ...When optimizingwebpages in order to achieve the best conversion rate,the traditional approach is to isolate and analyze themseparately through a sequence of experiments.In thispaper,wepropose a new framework to study a systemofwebpages simultaneously through the use of directed graph,fractional factorial design and simple optimization algorithm.The illustrative example shows that such complicated web systems can be easily studied and optimized by using the proposed methodology.展开更多
In this paper we present relevant contributions and important features related to the study of the retroreflectivity performance of pavement markings.The contribution of this paper is threefold.First,we propose an art...In this paper we present relevant contributions and important features related to the study of the retroreflectivity performance of pavement markings.The contribution of this paper is threefold.First,we propose an artificial scheme to allow some randomization of the treatments owing to several restrictions imposed on the choice of the experimental units.It is an experiment involving one fixed factor(three types of materials)in a randomized block design executed on a high-traffic-volume highway.Under this condition,the traffic volume works as a stress factor and the degradation of the retroreflectivity of pavement markings is faster than the degradation on rural roads or streets.This is related to the second contribution:the possibility of a reduction of experimental time.The current experiment spent 20 weeks to collect the data.And finally a mixed linear model considering three random effects and several fixed effects is fitted and the most relevant effects pointed out.This study can help highway managers to improve road safety by scheduling the maintenance of pavement marks at the appropriate time,choosing adequate material for the pavement markings and applying the proposed artificial scheme in future studies.展开更多
文摘For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the process and results in a mathematical description of the process behavior as a simple function based on the most important process factors can help to achieve higher production efficiency and quality.The present study aims at characterizing a well-known industrial process,the transesterification reaction of rapeseed oil with methanol to produce fatty acid methyl esters(FAME)for usage as biodiesel in a continuous micro reactor set-up.To this end,a design of experiment approach is applied,where the effects of two process factors,the molar ratio and the total flow rate of the reactants,are investigated.The optimized process target response is the FAME mass fraction in the purified nonpolar phase of the product as a measure of reaction yield.The quantification is performed using attenuated total reflection infrared spectroscopy in combination with partial least squares regression.The data retrieved during the conduction of the DoE experimental plan were used for statistical analysis.A non-linear model indicating a synergistic interaction between the studied factors describes the reactor behavior with a high coefficient of determination(R^(2))of 0.9608.Thus,we applied a PAT approach to generate further insight into this established industrial process.
文摘Identification of process parameters,their effects and contributions to the outcomes of the system using experimental approach could be a daunting,time consuming,and costly course.Using proper statistical methods,i.e.,Taguchi method,could significantly reduce the number of required experiments and statistical significance of the parameter can be identified.Friction stir welding is one of those welding techniques with many parameters which have different effects on the quality of the welds.In friction stir welding the tool rotational speed(RPM)and transverse speed(mm/min)influence the strength(i.e.,hardness distribution)of the stirred zone.In this study,these two factors are investigated to determine the effect they will have on the hardness in the stirred zone of the friction stir welds and how the two factors are related to one another for as-cast magnesium alloy AM60 with nominal chemical composition of Mg-(5.5-6.5)Al-(0.24-0.6)Mn-0.22Zn-0.1Si.Experimental data was taken at three different tool rotational speeds and three different transverse speeds.The data obtained was then analyzed using a 32 factorial design to find the contribution of these parameters.It was determined that both tool rotational speed and transverse speed possess significant effects on the stir zone hardness.Also,the interactions between the two factors were statistically assessed.
文摘Experiment statistical method and genetic algorithms based optimization method are used to obtain the optimum differential gear ratio for heavy truck that provides best fuel consumption when changing the working condition that affects its torque and speed range. The aim of the study is to obtain the optimum differential gear ratio with fast and accurate optimization calculation without affecting drivability characteristics of the vehicle according to certain driving cycles that represent the new working conditions of the truck. The study is carried on a mining dump truck YT3621 with 9 forward shift manual transmission. Two loading conditions,no load and 40 t,and four on road real driving cycles have been discussed. The truck powertrain is modeled using GT-drive,and DOE-post processing tool of the GT-suite is used for DOE analysis and genetic algorithm optimization.
基金The support of the staff at the Wolfson Centre for Bulk Solids Handling Technology of the University of Greenwich to execute the experiments with the rotary impact tester is highly appreciated.We thank Ed Stok,Freek Brakel,Andre van den Bosch,Shreyas Sridhar,and Otto Cramwinckel for their help with the experiments at the Delft University of TechnologyThis work was financially supported by the Top Consortium for Knowledge and Innovation for the Biobased Economy(TKI-BBE),under grant number BBE-1713(Biomassa pellets:degradatie tjdens transport en handling).
文摘This work investigates the proportion of generated fines in a pilot-scale experiment using a belt conveyor and commercial fuel pellets.For this,a belt conveyor with a length of 3.1 m was used and operated at varying conditions:speeds,percentages of material loading on the belt,two combinations of the inclination angle of the belt and the falling height,and a different number of handling steps.We considered a design of experiments approach based on response surface methodology to investigate the effect of different conditions on the potential of fines generation.Moreover,a comparison between the results of the belt conveyor and three common benchmark experimental approaches(tumbling box,rotary impact tester,and mechanical compression test)was made.Results show that the number of handling steps and the combined effect of drop height and inclination angle directly affected the fines generation.However,the tested belt speed range and the level of loading were of lower significance.A polynomial quadratic model was derived based on the regression analysis and showed a high accuracy to predict the proportion of fines.Moreover,the tumbling box method showed good potential to predict the proportion of fines in a belt conveyor when transported several times.
基金The authors would like to thank the CIPET:IPT Ahmedabad for the grant to provide a facility in which to carry out this study.
文摘Fused deposition modeling is one of the most adaptable additive production method as a result of the value-effectiveness and environment-friendly nature.However,FDM technique nevertheless possesses primary problems in phrases of negative surface best due to including layer by using layer production method for the prototypes.It is acceptable to explore an efficient method for FDM elements to enhance the bad surface first-rate and dimensions precision.In the present research paper,an effort has been made to decorate the surface better and optimize the vital processing parameter of FDM based benchmark the use of vapor smoothing procedure(VSP).A comparative experimental take a look at has been completed by layout of experiments,Taguchi technique to analyse impact of input layout parameters at the floor finish of benchmark FDM parts.The outcomes of prevailing research display that VSP treatment improves the surface excellent of FDM components to micro stage with negligible dimensional variation.It is observed that improved floor excellent is observed in the 1,2,-Dichloroethane chemical at 90°component construct orientation,0.25 mm layer thickness,10%fill density and 90 sec Exposure times.
基金Supported by National Natural Science Foundation of China(Grant No.51575393)
文摘Automotive torque converters have recently been designed with an increasingly narrower profile for the purpose of achieving a smaller axial size and reducing weight. Design of experiment(DOE) and computational fluid dynamics(CFD) techniques are applied to improve the performance of a flat torque converter. Four torque converters with different flatness ratios(0.204, 0.186, 0.172, and 0.158) are designed and simulated first to investigate the effects of flatness ratio on their overall performance, including efficiency, torque ratio, and impeller torque factor. The simulation results show that the overall performance tends to deteriorate as the flatness ratio decreases. Then a parametric study covering six geometric parameters, namely, inlet and outlet angles of impeller, turbine, and stator is carried out. The results demonstrate that the inlet and outlet angles play an important role in determining the performance characteristics of a torque converter. Furthermore, the relative importance of the six design parameters is investigated using DOE method for each response(stall torque ratio and peak efficiency). The turbine outlet angle is found to exert the greatest influence on both responses. After DOE analysis, an optimized design for the flat torque converter geometry is obtained. Compared to the conventional product, the width of the optimized flat torque converter torus is reduced by about 20% while the values of stall torque ratio and peak efficiency are only decreased by 0.4% and 1.7%, respectively.The proposed new optimization strategy based on DOE method together with desirability function approach can be used for performance enhancement in the design process of flat torque converters.
文摘The concept of Quality by Design was demonstrated in the development of a stability-indicating assay and related substances method by HPLC for Dabigatran Etexilate Capsules dosage form. Method design, method evaluation, method control and life cycle management were explained by systematic flow chart. Analytical Target Product profile was defined. The method was developed using the Inertsil ODS-3V, 150 mm × 4.6 mm, 5 μm column using the gradient program with ammonium formate buffer as mobile phase A and acetonitrile as mobile phase B. Risk assessment was performed as part of method evaluation. Design of experiment tools was used to optimize the chromatographic conditions. A two-level Full Factorial Design along with Face Centered Central Composite design augmentation was employed and statistical analysis of the experimental data uncovered the significant influential of chromatographic factors. The design space and the contour plot suggest that the current center point parameters can be further modified, resulting in better acceptability of the response parameters. The performance of the optimized method was validated according to current ICH guidelines. Dabigatran Etexilate Capsules was subjected to various stress conditions like oxidative, acid, base, hydrolytic, thermal, humidity, and photolytic degradations and evaluated chromatograms at 220 nm. The degradation products were well separated from each other and main peak, demonstrating the stability-indicating power of the method. One of the major degradant impurities, which are forming in neutral hydrolysis stress condition, is isolated and characterized by using analytical techniques like IR, LC-MS and NMR. Degradation pathway for Dabigatran Etexilate was proposed based on forced degradation data along with reaction mechanism.
基金supported by The Center for Automotive Research at The Ohio State University and the Department of Mechanical and Aerospace Engineering at The Ohio State University.
文摘The increasing use of lithium-ion cells in large-scale,long-term applications drives a need for design methods that considers aging and accurate state of health estimation.A common approach is to rely on an empirical or semiempirical aging model fit to experimental data to estimate the evolution of capacity and power fade.Because aging data are costly to collect,pack designers either use Design of Experiment(DOE)techniques to define a set of efficient tests,or use existing aging data to calibrate aging models.Given the increasing quantity of available aging data,the question arises:how can experimental aging campaigns be quickly compared?However,a methodology for the comparison of sets of aging experiments is not discussed in the literature.As a result,pack designers usually rely on intuition to select between multiple aging studies proposed by DOE techniques or in the literature.This work proposes metrics to quantitatively capture the alignment between a set of aging experiments and a target application.These metrics allow pack designers to quickly compare many sets of aging experiments to evaluate those which have tested conditions relevant to the application.Case studies are presented to illustrate the application of these metrics using aging campaign data from the literature.To validate these metrics,this work examines the relationship between these metric values and aging model validation error for calendar aging data for 18650 NMC battery cells.It is demonstrated that greater metric values correspond to reduced model error for an empirical capacity fade model.
文摘The bonded-particle model(BPM)is commonly used in the numerical analysis of ore samples.To improve the accuracy of simulating the mechanical process of ore process of ore crushing in a crusher,the parameters of the BPM for the ore must be calibrated.In this study,a calibration method was proposed for the scientific determination of the parameters of the BPM for ore undergoing uniaxial compression.First,physical tests and simulations were conducted to determine the mechanical response(uniaxial compressive strength and macroscopic stiffness)of ore during uniaxial compression.Then,the sensitivity of the mechanical response to the values of microscopic parameters was tested using a Plackett-Burman design.Next,the microscopic parameters with the greatest impact on the response were identified,and the range of parameters that met the target response was determined using a steepest ascent design;Second,a second-order model of the mechanical response was established using the sensitive parameters by combining a Box-Behnken design with response surface methodology to obtain the optimal BPM parameters.Simulation tests showed that the normal stiffness per unit area,critical shear stress,and bonded disk radius had significant effects on the uniaxial compressive strength(UCS)and macroscopic stiffness(MS).To verify the validity of the proposed calibration method,laboratory tests were conducted.The consistency of the simulation results with experimental results indicated that response surface methodology with the Plackett-Burman design,steepest ascent design,and Box-Behnken design can be an effective method for calibrating the BPM of ores.
文摘In this paper, a square textured parallel slider is considered for a study to improve the hydrodynamic performance of moving parts. The numerical method is employed for the analysis of a square texture with different bottom profiles:flat, triangle T1, triangle T2, and curved. The governing Reynolds equation is solved using a finite difference numerical discretization technique with the Gauss–Seidel iterative scheme. To obtain optimized process parameters, the response surface methodology-based central composite design along with grey relational analysis multi-objective optimization is used. The multi-objective responses are the load capacity and friction coefficient. The triangle T2 bottom profile yields the highest load capacity and the lowest friction coefficient compared to flat, triangle T1, and curved bottom profiles, of which the triangle T1 bottom profile yields the worst results. For the triangle T2 bottom profile, the flow speed is found to be the most significant process parameter, followed by the aspect ratio. Texture density is found to be the least significant parameter based on increasing the load capacity and decreasing the friction coefficient.
基金the National Science and Technology Major Project(Grant No.21010098)the National Key Technologies R&D Program of Henan(Grant No.162102210048)+1 种基金Henan Provincial Key Laboratory of High Performance Bearing Technology(Grant No.2016ZCKF02)the platform of Henan Collaborative Innovation Center for Advanced Manufacturing of Mechanical Equipment.
文摘To explore the forming process and mechanism of the surface texture of laser micropits,this paper presents the thermal model of laser machining based on the Neumann boundary conditions and an investigation on the effects of various parameters on the processing.The surface profile and quality of the formed micropits were analyzed using NanoFocus 3D equipment through a design of experiment(DOE).The results showed that more intense melting and splashing occurred with higher power density and narrower pulse widths.Moreover,the compressive stress is an important indicator of the damage effects,and the circumferential thermal stress is the primary factor influencing the diameter expansion.During the process of laser machining,not only did oxides such as CuO and ZnO generate,the energy distribution also tended to decrease gradually from region#1 to region#3 based on an energy dispersive spectrometer(EDS)analysis.The factors significantly affecting the surface quality of the micropit surface texture are the energy and pulse width.The relationship between taper angle and energy is appropriately linear.Research on the formation process and mechanism of the surface texture of laser micropits provides important guidance for precision machining.
基金Sponsored by the National Defense Basic Scientific Research Program(Grant No.A0320110019)the Shanghai Science and Technology Innovation Action Plan(Grant No.11DZ1120800)
文摘To promote the pose accuracy performance of a spatial parallel kinematic Mechanism( PKM) in service,a workshop oriented tolerance synthesis method based on design of experiment( DOE) is proposed,which involves two consecutive stages. In the first stage of DOE,the tolerance factor sensitivities are obtained according to initial tolerance settings with the consideration of the current manufacturing capacity,and the second stage of DOE makes use of them to produce multiple tolerance allocations which can adapt to current manufacturing capacity. A tolerance synthesis procedure is developed and integrated in tolerance design system for PKM. Comparing the results with peer method,the validity and practicability of this method is verified.
文摘This work investigates the reuse of natural(SCB)and minopropyltriethoxysilanemodifed(MSCB)sugarcane bagasse fbres in cementitious composites.ugarcane bagasse fbres are pre-used in the treatment of motor oil contaminated effluents.A full factorial design is used to identify the effects of fbre type(SCB and MSCB),fbre length(0.6 and 1.2 mm),fbre amount(1 and 2 wt%)and fbre condition(before and after oil filtration)on apparent density,water absorption,apparent porosity,ultra-pulse velocity,dynamic modulus,flexural strength and modulus.SCB fibres lead to increased apparent density compared to MSCB fibre reinforced composites.MSCB fibres contribute to reduce composite porosity,leading to higher mechanical properties.The smaller area of MSCB fibres promotes a larger amount of cementitious phase per unit volume,thus increasing the strength of the sample.Longer sugarcane fbres(1.2 mm)have a larger surface area,leading to a higher fibre concentration per unit volume,which increases water absorption.The amount of fibre has no significant effect on mechanical and physical responses.Composites made with 2 wt%0.6 mm long MSCB fibres achieve promising results for non-structural civil engineering applications.
基金The Cotton Textiles Research Trust with the project"Protective Efficiency of Respiratory Protective Equipment against Byssinosis for Cotton Workers"The University of Manchester through project AA14512(UMRI project"Graphene-Smart Textiles E-Healthcare Network")。
文摘Electrospun poly(vinylidene fluoride)(PVDF)nanofiber web has been widely utilized as a functional material in various flexible sensors and generators due to its high piezoelectricity,ease processability,and low cost.Among all the crystalline phases of PVDF,β-phase is a key property for PVDF nano fiber web,because the con tent of β-phase is directly proporti onal to piezoelectric performa nee of PVDF nano fiber web.Herein,the impact of graphe ne con tent(GC),tip-to-collector dista nee(TCD),and rotational speed of collector(RSC),as well as their interactions on theβ-phase formation of PVDF nano fiber web is systematically investigated via design of experime ntal method.The fraction of each crystalline phase of PVDF nano fiber web is calculated by FTIR spectra,and the crystallinity is determined by XRD patterns.The influences of GC,TCD,and RSC on both β-phase fraction and crystallinity of PVDF nanofiber are analyzed using Minitab program.The results show that GC,TCD,and RSC all have significa nt effect on the β-phase content of PVDF nano fiber web,and GC is the most significant one.In addition,an optimal electrospinning condition(GC=1 wt%,TCD=4 cm,and RSC=2000 r·min^-1)to fabricate high 0-phase crystallinity of PVDF nanofiber web is drawn,under which the crystallinity can reach 41.7%.The contributions in this study could provide guidanee for future research on fabricating high performance PVDF nanofiber web based sensors or generators.
基金The authors recognize the support obtained from the Centre of Excellence on Microstructurally Designed Advanced Materials Development under TEQIP-II,IIEST Shibpur.The assistance granted from DST-FIST to set up Advanced Tribology Laboratory under the Department of Mechanical Engineering,IIEST Shibpur is also highly appreciated.
文摘A comprehensive study of the tribological performance of the Al-Zn-Mg-Cu/Al2O3 composite and its matrix alloy is presented in this paper, with a specific emphasis to identify and model the applicable wear conditions where the composite provides a minimum of 50% reduction in wear rate and 25% lowering of the friction coefficient. Two-body abrasion experiments following Taguchi L27 orthogonal design have been performed separately on alloy and composite materials, both prepared by the stir casting method. The influence of crucial control factors including silicon carbide (SiC) abrasive size, load, sliding distance, and velocity on the percentage variations of wear rates and friction coefficients between alloy and composite have been studied using the analysis of variance technique and full quadratic regression method. The dominant control factors are identified as abrasive size, load, and the interaction between abrasive size and load. This has been verified by establishing the influence of abrasive size and load on variations of wear mechanisms like microcutting, microploughing, and delamination, identified by means of in-depth characterization of worn surfaces and generated debris for both alloy and composite. The selection of applicable tribological condition for the composite has been accomplished by adopting the multi-response optimization technique based on combined desirability approach to obtain concurrent optimization of the percentage variations of wear rates and friction coefficients. Predictive models correlating the superiority of tribological performance of composite with abrasion conditions have been developed, and these are found to be accurate (errors <10%), as determined by confirmatory experiment.
文摘A five-step method framework is proposed by combing improved value stream mapping with simulation and design of experiment(DOE) to design the lean system for engineer-to-order(ETO) manufacturing,and lean practice implementation path is decided.Meanwhile,a real company case like HAVC is taken to display the application of the framework.The results indicate that compared to supermarket Kanban,constant work in process(Conwip) has the broader applicability in ETO manufacturing and the critical business process,like purchasing of key parts,and has more significant effects on value stream performance.Therefore,it should have priority in lean practice implementation.
文摘When optimizingwebpages in order to achieve the best conversion rate,the traditional approach is to isolate and analyze themseparately through a sequence of experiments.In thispaper,wepropose a new framework to study a systemofwebpages simultaneously through the use of directed graph,fractional factorial design and simple optimization algorithm.The illustrative example shows that such complicated web systems can be easily studied and optimized by using the proposed methodology.
文摘In this paper we present relevant contributions and important features related to the study of the retroreflectivity performance of pavement markings.The contribution of this paper is threefold.First,we propose an artificial scheme to allow some randomization of the treatments owing to several restrictions imposed on the choice of the experimental units.It is an experiment involving one fixed factor(three types of materials)in a randomized block design executed on a high-traffic-volume highway.Under this condition,the traffic volume works as a stress factor and the degradation of the retroreflectivity of pavement markings is faster than the degradation on rural roads or streets.This is related to the second contribution:the possibility of a reduction of experimental time.The current experiment spent 20 weeks to collect the data.And finally a mixed linear model considering three random effects and several fixed effects is fitted and the most relevant effects pointed out.This study can help highway managers to improve road safety by scheduling the maintenance of pavement marks at the appropriate time,choosing adequate material for the pavement markings and applying the proposed artificial scheme in future studies.
