Effects Of Control Factors Research Articles

Micro/nano-encapsulation of a phase change material by coaxial electrospray method

This study is focused on the preparation of n-nonadecane-loaded calcium alginate capsules by coaxial electrospray technique. The solution and process parameters such as sodium alginate concentration, polymer feeding rate, needle gauge, needle length, needle-to-collector distance, and stirring speed were optimized through Taguchi method. These parameters were selected as variables, and three levels of them were introduced into L27 orthogonal arrays. Taguchi’s signal-to-noise ratio and analysis of variance were used to minimize the response and find the effect of control factors on it, respectively. The setup of the two-axial nozzle and feed rates of core/shell solutions were studied, as well. Optical microscopy, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy were used for characterization of the capsules. The results showed that the sodium alginate concentration and the needle gauge are important factors for capsulated alginate material. The optical microscope images and the FTIR spectra confirmed that the alginate shell successfully fabricated the n-nonadecane materials. SEM analysis showed that at the optimal conditions, micro- and nano-capsules were prepared with nearly spherical shape. The results showed that when the inner needle tip was displaced 0.5 mm ahead of the tip of the outer needle, the envelopment of the core polymer was better accomplished by the outer polymer.

Design-of-experiments application in machining titanium alloys for aerospace structural components

The present investigation is an attempt to study the effect of control factors i.e. the cutting speed, the feed rate, and the titanium alloys on response variables i.e. the cutting force, the feed force and the cutting tool temperature by using the Taguchi techniques. A number of experiments were conducted using the L18 orthogonal array on a CNC vertical machining center. The machining center was configured to act as a lathe with the tool oriented to produce an orthogonal cut. A combined technique using orthogonal array and analysis of variance was employed to investigate the contribution and effects of cutting speed, feed rate and different aerospace grade titanium alloys (Ti6Al4V, Ti54M and Ti10.2.3) on two force components and cutting tool temperature. The results revealed that the feed rate was the most influential factor which affects the cutting and feed forces, while the cutting speed had most significant effect on the cutting tool temperature. Thereafter, optimal control factors were obtained for minimum response variables.

The evaluation of the effects of control factors on surface roughness in the drilling of Waspaloy superalloy

In this study, the effects of cutting tool type (Ct), cutting speed (Vc), feed rate (f) and drill bit angle (A) on the average surface roughness (Ra) were investigated in the drilling of Waspaloy superalloy with coated and uncoated solid carbide drills. Experimental studies were performed in the orthogonal array of L18 (21×33) by using Taguchi method. A second order predictive equation was developed with Linear Regression Analysis and coefficient of correlation for Ra calculated as R2=96.9%. The most effective parameters on Ra were determined as A, f, Vc and Ct with 49.44%, 15.0%, 14.45% and 13.47% contribution ratios, respectively. Ra surface roughness values increased with the increasing tool wear. In this study, the chip formation and tool wear were also evaluated. Three types chip formation such as spiral chip, string chip and short chip were observed in the drilling of Waspaloy with solid carbide drills.

Kinetic modeling of pseudoliving free-radical styrene polymerization occurring via reversible addition-fragmentation chain transfer

A kinetic model has been constructed for 2,2′-azobisisobutyronitrile-initiated pseudoliving free-radical styrene polymerization occurring via reversible addition-fragmentation chain transfer in the presence of dibenzyl trithiocarbonate. The inverse problem of determining the unknown temperature-dependent rate constants of the elementary reactions of the kinetic scheme has been solved. The model has been validated by comparing the theoretical and experimental molecular weight characteristics of polystyrene. The model has been employed to investigate the effects of control factors of the process on the molecular weight characteristics of polystyrene.

Optimization of the Paper Permeability Tester using Robust Design

This paper is using practical case study of robust design engineering. Effect of control factors and optimum condition is studied to design a more robust Paper Permeability Tester. In this study, robustness means decreasing uncertainty that is validity of measurement results with the Tester. Robustness is required to ensure the reliabilityfor the measurement results in the field of the measurement tester. Thus, orthogonal array L18 is employed and the optimum condition was obtained for decreasing the measurement dispersion. Experiment reproducibility of Signal-to-Noise Ratio and sensitivity were confirmed within 20%. SNR value is linearly depends on air permeance value. When the value of air permeance is small, it tends to provide small SNR. Flow rate in nozzle was considered as a major cause. Stability of flow in the nozzle is significant to design the Tester to be more robustness.In a case of a flow under the rapidly, SNR is small due unstable flow. Sensitivity with nozzle diameter was dramatically large. Nozzle specification tolerance wasfound to have strong influence on measurement result.

Statistical Testing Procedure for the Interaction Effects of Several Controllable Factors in Two-Valued Input–Output Systems

Suppose several two-valued input–output systems are designed by setting the levels of several controllable factors. For this situation, the Taguchi method has proposed assigning the controllable factors to the orthogonal array and using analysis of variance (ANOVA) for the standardized signal–noise (SN) ratio, which is a natural measure for evaluating the performance of each input–output system. Though this procedure is simple and useful in application indeed, the result can be unreliable when the estimated standard errors of the standardized SN ratios are unbalanced. In this article, we treat the data arising from the full factorial or fractional factorial designs of several controllable factors as the frequencies of high-dimensional contingency tables, and propose a general testing procedure for the main effects or the interaction effects of the controllable factors.

Molecular dynamics simulation of average velocity of lithium iron across the end of carbon nanotube

The velocity of lithium iron across the entrance of carbon nanotube VLi is an important factor for the charge performance of lithium iron battery. The molecular dynamics simulation is adopted to evaluate the effects of control factors which include electric strength, functional group type, the diameter of carbon nanotube and temperature. By the L16(45) orthogonal array method, the simulations are carried out. The order of influences of control factors is electric filed intensity > functional group > diameter > temperature. Within the ranges of the control factors studied in this work, VLi increases with increasing the diameter of carbon nanotube and electric field strength. VLi decreases with successively modifying the functional groups at the end of carbon nanotube into -H, -OH, -NH2 and -COOH. With the increasing of temperature, VLi first increases then decreases, but on the whole its change is not big.

Modeling of EDM responses by support vector machine regression with parameters selected by particle swarm optimization

Electrical discharge machining (EDM) is inherently a stochastic process. Predicting the output of such a process with reasonable accuracy is rather difficult. Modern learning based methodologies, being capable of reading the underlying unseen effect of control factors on responses, appear to be effective in this regard. In the present work, support vector machine (SVM), one of the supervised learning methods, is applied for developing the model of EDM process. Gaussian radial basis function and ε-insensitive loss function are used as kernel function and loss function respectively. Separate models of material removal rate (MRR) and average surface roughness parameter (Ra) are developed by minimizing the mean absolute percentage error (MAPE) of training data obtained for different set of SVM parameter combinations. Particle swarm optimization (PSO) is employed for the purpose of optimizing SVM parameter combinations. Models thus developed are then tested with disjoint testing data sets. Optimum parameter settings for maximum MRR and minimum Ra are further investigated applying PSO on the developed models.

Multi-objective optimization using Taguchi based grey relational analysis for micro-milling of Al 7075 material with ball nose end mill

This study was carried out to understand micro-milling of aluminum material with ball nose end mill and consisted of four stages: experimental work, modelling, mono and multi objective optimization. In the first stage (experimental work), micro-milling experiments were carried out using Taguchi method. The effects of spindle speed, feed per tooth and depth of cut on tool wear, force and surface roughness were investigated. Cutting tools and workpiece surfaces were also inspected via scanning electron microscope. Adhesion and abrasion wear mechanisms during micro-milling of aluminum were observed. Workpiece surfaces had the accumulations of plastically deformed workpiece material due to the high ductility of aluminum. In the second stage (modelling), all data gathered in the experimental works were utilized to formulate first-order models with interaction. These first-order models with interaction could be used to predict responses in micro-milling of aluminum with a minor error. In the third stage (mono-objective optimization), responses were used alone in optimization study as an objective function. To minimize all responses, Taguchi’s signal to noise ratio was used. The effect of control factors on responses was determined by analysis of variance. In the fourth stage (multi objective optimization), responses were optimized simultaneously using grey relational analysis.

Optimizations of Edm Process Parameters for Surface Roughness Machining Die Steel Using Copper Tungsten Electrode by Adopting Taguchi Array Design

In this paper, machining of hard material High Carbon High Chromium (HCHCr) die steel using Electrical Discharge Machining (EDM) with a Copper-tungsten electrode by using Tagughi methodology has been reported. The Taguchi method is used to formulate the experiment format, to analyze the effect of each control factors on machining characteristics, and predicts the optimal EDM control factor such as Servo voltage, pulse current, pulse duration and interval time. It is found that these control factors have a significant influence on machining characteristics such as material removal rate, electrode wear and Surface roughness. In order to see the impact of control factors on quality characteristic, number of experiments were conducted and. results were analyzed by Taguchi methodology and analysis of variance (standard analysis). The effect of control factors were examined for obtaining optimum surface roughness. The analysis of Taguchi method reveals that, peak current, servo voltage and pulse duration have significantly affected the surface roughness.

Fuzzy reasoning system design and assessment of load-bearing endoprostheses and their fabrication processes

Five attempts of an application of a fuzzy reasoning approach to problems encountered in biomechanics and engineering of biomaterials are presented. They include: (A) assessment of maximum contact stress acting on endoprosthesis, (B) design of sintering plan to obtain a porous/scaffold implant, (C) design of oxidation plan to obtain nanotubular oxide structure on the Ti alloy, (D) and (E) design of deposition of hydroxyapatite coating on the Ti alloy. The fuzzy reasoning system is shown to well predict: the maximum contact stress estimation on acetabular surface of the load-bearing hip joint endoprosthesis for chosen and given Wiberg’s angle values and patient’s body weight; the optimal geometry of scaffold’s architecture; the geometry of TiO2 nanotubular layer on titanium surface and directions of the adjustment of fabrication conditions; the ratio of Ca/P and the coating crystallinity; effects of control factors (sintering temperature and content of ZnO) on mechanical properties of BHA-ZnO composite. A small deviation of the predicted values from those obtained in the course of experiments can be decreased by improvement of the proposed fuzzy model i.e. adjusting fuzzy membership functions of input and output variables.

Tensile and Flexural Properties of MMT-Clay/ Unsaturated Polyester Using Robust Design Concept

The effect of nanoclay on the mechanical properties of Isophthalic unsaturated polyester was studied with the help of robust design Concept. Organo modified MMT nanoclay (Nanomer 1.31PS) was used as reinforcement. The weight percentage of nanoclay, impeller blade design, mixing hours and mixing speed were taken as control factors. In Taguchi design of experiments, L9 orthogonal array was employed to investigate the effect of control factors on mechanical properties such as tensile and flexural strength. X-ray diffraction (XRD) and Atomic force microscopy (AFM) results show the intercalation /exfoliation of clays in the polyester matrix.

Analysis of Material Removal Rate and Surface Roughness on Advanced Ceramics Materials Micro-Hole Drilling

This study discussed the rotary ultrasonic machining (RUM) parameters and tool geometry parameters of optimized hole wall quality, and obtained better and uniformly distributed surface roughness of deep hole walls. The experimental configuration of this study was planned using Taguchi orthogonal array, where the hole diameter, spindle speed, feed rate and power were taken as the experimental factors. Drilling machining experiment was carried out using the parameter combination configured by the experimental design, and wall surface roughness of the drilled holes was measured. A relation model between the average surface roughness and standard deviation of the hole walls and processing parameters and tool geometry were established, so as to achieve optimized surface roughness of the overall deep hole walls. The optimization process respectively aimed at the minimum surface roughness and maximum metal removal rate. The experimental results proved that application of the optimized parameter combination in rotary ultrasonic machining of hole processing can obtain better and more uniform hole wall surface quality.The effect of control factors on the hole quality was discussed from the respects of the straightness deviation, minimum surface roughness and maximum metal removal rate of related factors on the hole when the Taguchi method was applied to rotary ultrasonic machining of hole drilling. The results showed that the level of straightness factors of produced holes can be fully presented. Keywords-Advanced Ceramics; Rotary Ultrasonic Machining; Surface Roughness; Material Removal Rate; Holes Deviation; Taguchi Method

Analysis of the Material Removal Rate of Micro-Hole Machining of Ceramic Materials

This study discussed what rotary ultrasonic machining (RUM) and tool geometry parameters combination can obtain bigger material removal rate (MRR) in drilling. The experimental configuration of this study was planned using Taguchi orthogonal array, where the drill diameter, rotation speed, power and feed rate were taken as the experimental factors. A relation model among the MRR and standard deviation of the holes walls and processing parameters and tool geometry was established, so as to achieve maximum MRR of the overall deep holes walls. The experimental results proved that application of the optimized parameters combination in rotary ultrasonic machining of holes processing can obtain bigger and better removal rate of holes walls. The effect of control factors on the holes quality was discussed from the straightness deviation and maximum material removal rate of related factors on the holes when the Taguchi method was used in rotary ultrasonic machining of holes drilling. The results showed that rotation speed, power, and feed rate under bigger level have a larger MRR than that of other level in a fixed drill diameter.

Implementation of an in vitro bioassay as an indicator of the bionutrient FitoMas E

Seed bioassays are employed to determine the stimulatory effect of various biological products on the seed germination of plants used for the detection and control of toxic environmental contaminants. The objective of the present study was to design an in vitro bioassay to monitor the quality of the final production of FitoMas E, a bionutrient derived from the sugar industry and produced by the Instituto Cubano de Investigaciones de los derivados de la Cana de Azucar By-Products (ICIDCA), by determining rates of seed germination and growth of lettuce ( Lactuca sativa L. ) as an indicator plant. A significant effect of controllable factors under study (FitoMas E concentration in lots and replicates of Petri dishes) was determined by one-way and multifactor ANOVA analysis. In all cases, the highest values of relative germination and growth occurred at a concentration of FitoMas E of 0.1 mL L -1 , with a marked increase in the growth of hypocotyl (RHG), which decreased at concentrations of 2.5 and 5 mL L -1 . These results can be explained by the hormesis phenomenon, which is characterized by stimulation at low doses and inhibition at high doses. For a confidence level of P ≤ 0.05, there were no significant differences between Petri dishes with lettuce seeds and lots in all responses tested. The bioassay method implemented in this study was fast, simple and reliable

Analyzing the Effect of Process Parameters on the Shape of 3D Profiles

This paper investigates the effect of process parameters on the shape of three-dimensional (3D) curves. Compared with recent literature on profile modeling (generally used for process monitoring applications), the main novelty consists of dealing with curves that do not lie in a plane but in space. In particular, a generalization of principal component analysis (PCA), based on the appropriate use of complex rather than real numbers (complex PCA), is used as a modeling tool. Scores of the significant components obtained via complex PCA are then used as data input for the analysis of variance to investigate the effect of process parameters on the machined shape. The first advantage of complex PCA is its insensitivity to rotation about the origin of the complex plane, a property that produces a significant simplification of the preliminary step of profile registration. Second, complex PCA outperforms alternative PCA-based approaches in terms of the power of detecting the effect of controllable factors on the profile shape. The proposed procedure is particularly useful when the quality characteristic of interest is related to geometric tolerances, as shown in a real case study of the axial straightness of lathe-turned items.

Design and Analysis of Enhanced Chromium Nitride Film Performance by Tuning Sputtering Magnetic Systems

This paper presents the optimal chromium nitride (CrN) deposited performance by tuning magnetic systems on die steel in PVD. The strength of magnetic fields was controlled by adjusting the gap distance between magnet sets and target surfaces of the unbalanced magnetic field of sputtering systems. In L18 orthogonal experiments, the effect of control factors were explored such as gap distance between magnet set and target surface (GDMT), target current, argon and nitrogen flow rate, DC pulse frequency, and work distance. Hardness and wear behavior of the CrN films were analyzed using a statistical method. The wear rate was estimated by Pappus’s theorem. Among the results, the Cr2N phase with the mixture crystallographic orientations of (111) and (002) exhibited better wear resistance than CrN(200) with a single preferential orientation. In addition, variance analysis exhibited the largest percentage contribution to friction coefficient in comparison with the other two properties of friction coefficient and GDMT, which showed that GDMT is extremely sensitive to friction coefficient.

Development of new rapid prototyping process

PurposeThe purpose of this paper is to identify the key elements of a new rapid prototyping process, which involves layer‐by‐layer deposition of liquid‐state material and at the same time using an ultraviolet line source to cure the deposited material. This paper reports studies about the behaviour of filaments, deposition accuracy, filaments interaction and functional feasibility of system. Additionally, the author describes the process which has been proposed, the equipment that has been used for these studies and the material which was developed in this application.Design/methodology/approachThe research has been separated into three study areas in accordance with their goals. In the first, both the behaviour of filament and deposition accuracy was studied. The design of the experiment is described with focus on four response factors (bead width, filament quality, deposition accuracy and deposition continuity) along with function of three control factors (deposition height, deposition velocity and extrusion velocity). The author also studied the interaction between filaments as a function of bead centre distance. In addition, two test samples were prepared to serve as a proof of the methodology and to verify the functional feasibility of the process which has been studied.FindingsThe results show that the proposed process is functionally feasible, and that it is possible to identify the main effects of control factors over response factors. That analysis is used to predict the condition of process as a function of the parameters which control the process. Also identified were distances of centre beads which result in a specific behaviour. The types of interaction between filaments were analysed and sorted into: union, separation and indeterminate. At the end, the functional feasibility of process was proved whereby two test parts could be built.Originality/valueThis paper proposes a new rapid prototyping process and also presents test studies related to this proposition. The author has focused on the filament behaviour, deposition accuracy, interaction between filaments and studied the functional feasibility of process to provide new information about this process, which at the same time is useful to the development of other rapid prototyping processes.

Adaptive Neuro-Fuzzy Approach for Predicting Hardness of Deposited TiN/ZrN Multilayer Coatings

This paper presents an adaptive neuro-fuzzy approach based on first order function of fuzzy model for establishing the relationship between control factors and thin films properties of TiN/ZrN coatings on Si(100) wafer substrates. A statistical model was designed to explore the space of the processes by an orthogonal array scheme. Eight control factors of closed unbalance magnetron sputtering system were selected for modeling the process, such as interlayer material, argon and nitrogen flow rate, titanium and zirconium target current, rotation speed, work distance, and bias voltage. Analysis of variance (ANOVA) was carried out for determining the influence of control factors. In this study, with the application of ANOVA, the smallest effect of control factors was eliminated. The adaptive neuro-fuzzy inference system (ANFIS) was applied as a tool to model the deposited process with five significant control factors. The experimental results show that ANFIS demonstrates better accuracy than additive model for the film hardness. The root mean square error between prediction values and experimental values were archived to 0.04.

Application of response surface methodology for robustness of responses of yttria stabilized zirconia coatings

This article presents an application of surface response methodology and the design of an experiment to develop robust wear-resistant characteristics for partially stabilized zirconia coatings in plasma spraying processes. In this study, the effects of control factors on the porosity percentage and wear resistance responses are evaluated and discussed. The relationship between the responses with significant factors is established. By employing a response surface methodology, a series of mathematical regression models can be efficiently performed. These response models are applied to analyze the response surface contours and surface plots to estimate all responses simultaneously for developing a better deposition performance for plasma spraying processes. The experimental results obtained show that using an experimental design strategy with a quadric model proposed is used not only for predicted optimal process parameters for achieving the desired quality but also for process optimization. Several response plots were generated to examine parameter effects on the response profiles. The microstructures of the worn surface were examined and revealed a dense lamella and highly anisotropic with a slight plastic deformation through the optimal conditions.