Interaction Of Process Variables Research Articles

Evaluation of the Effects of Electroplating Conditions on the Material Properties of Iron Cobalt Thick Films Using Design of Experiments

The effects of electroplating conditions on the material properties of iron cobalt thick film alloys were investigated. Samples were prepared from sixteen different combinations of electrodeposition conditions (temperature, current density, pH, and bath composition) using a binary design of experiments. A parametric study was done to investigate the effects of the process variable interactions on the magnetic and material properties The results obtained show that FeCo films with superior magnetic saturation, magnetic permeability, and low film stress are electroplated from an aqueous bath under the following deposition parameters: a high temperature, a low pH, low current density, and a high iron to cobalt ratio.

Optimization of copper adsorption by chemically modified fly ash using response surface methodology modeling

Though copper is a necessary trace element but it can be toxic in higher concentration. Locally available fly ash was found to be low-cost adsorbent to remove copper from aqueous solution. Calcium oxide-treated fly ash was investigated in the study of scale up of copper removal. Response surface methodology (RSM) was used for the statistical optimization of the copper reduction process. A two-level-three-factor (23) full factorial central composite design with the help of Design Expert Version 7.0.0 (Stat Ease, USA) was used for the optimization of the copper adsorption process variables like: initial solution pH (3.5–5.5), initial copper concentration (15–50 mg/L), and contact time (45–90 min) and to evaluate the effects and interactions of process variables. The optimum reduction of copper was 99.16% at pH 3.98, 77.88 mg/L copper concentration, and 58.82 min of contact time. The percentage deviation between experimental and RSM model equation was 0.03%.

The Effect of Abrasive Water Jet Process Variables on Surface and Subsurface Condition of Inconel 718

Experiments were carried out in Inconel 718 in order to investigate the effect of abrasive water-jet process variables on surface and subsurface condition. A Design of Experiments (DoE) approach was taken, considering variables such as water pressure, traverse rate, abrasive mass flow rate and abrasive grit size. The experimental variables were related to taper ratio, surface roughness of different zones in the machined surface and subsurface condition (deformation and crater depth). Statistical analysis was carried out in order to develop mathematical models which include process variable interactions and quadratic terms. This led to models with high correlation and prediction power which allow a better understanding of the process and can form the base for further process optimisation. The models were validated with additional experiments and showed good agreement with the water jet system. The results showed that water pressure has a nonlinear behaviour in the quality of the surface and sub-surfaces and that interaction between the variables had a significant effect on the quality of the surfaces and sub-surfaces generated by the AWJ.

Scale-up of a dye adsorption process using chemically modified rice husk: optimization using response surface methodology

Abstract This article extends our previous study on malachite green (MG) adsorption using chemically modified rice husk at shake flask level, by investigating the scale up of the dye adsorption process to a laboratory level stirred batch reactor. Response surface methodology (RSM) was employed to investigate the effect of different operating conditions on the uptake of MG. A two level three factor (23) full factorial central composite design (CCD) with the help of Design Expert Version 7.1.6 (Stat Ease, USA) was used for the optimization of the adsorption process and to evaluate the effects and interactions of process variables: initial solution pH (4.0–10.0), initial dye concentration (100–500 mg/l), and adsorbent dose (10–50 g/l). Multiple response optimization was applied to the experimental data to discover the optimal conditions for a set of response, simultaneously, by using a desirability function. The optimum conditions for MG adsorption were found to be 8.30, 500 mg/l and 29.31 g/l respectively, ...

Scale-up of a dye adsorption process using chemically modified rice husk: optimization using response surface methodology

Abstract This article extends our previous study on malachite green (MG) adsorption using chemically modified rice husk at shake flask level, by investigating the scale up of the dye adsorption process to a laboratory level stirred batch reactor. Response surface methodology (RSM) was employed to investigate the effect of different operating conditions on the uptake of MG. A two level three factor (23) full factorial central composite design (CCD) with the help of Design Expert Version 7.1.6 (Stat Ease, USA) was used for the optimization of the adsorption process and to evaluate the effects and interactions of process variables: initial solution pH (4.0–10.0), initial dye concentration (100–500 mg/l), and adsorbent dose (10–50 g/l). Multiple response optimization was applied to the experimental data to discover the optimal conditions for a set of response, simultaneously, by using a desirability function. The optimum conditions for MG adsorption were found to be 8.30, 500 mg/l and 29.31 g/l respectively, for initial solution pH, initial dye concentration and adsorbent dose. Under these conditions, the removal efficiency was found to be 90.83%.

Optimization of Osmotic Drying Parameters for Button Mushroom (<i>Agaricus bisporus</i>)

Response surface methodology was used to investigate the effect of brine concentration (10% - 20%) solution temperature (35℃ - 55℃), and duration of osmosis (30 - 60 min) with respect to water loss (WL) and salt gain (SG). The solu- tion to sample ratio of 5/1 (w/w) was used. The Box-Behnken design of three variables and three levels including seventeen experiments formed by five central points were used for optimizing input parameters. Linear, quadratic and interaction effects of three variables were analyzed with respect to water loss and solid gain. For each response, second order polynomial models were developed using multiple regression analysis. Analysis of variance (ANOVA) was per- formed to check the adequacy and accuracy of the fitted models. The response surfaces and contour maps showing the interaction of process variables were constructed. The optimum operating conditions were: solution temperature 44.89℃, brine concentration of 16.53 per cent and duration of osmosis of 47.59 min. At this optimum point, water loss and salt gain were predicted to be 44.55 per cent and 2.98 percent respectively.

Characterisation of Abrasive Water-jet Process for Pocket Milling in Inconel 718

Experiments were carried out in Inconel 718 in order to investigate the possibility of using the abrasive water-jet process for producing 3D features such as pockets. A design of experiments approach was taken, considering variables such as water pressure, nozzle stand-off distance, traverse speed, nozzle orifice diameter, abrasive mass flow rate and tool-path step over distance. The experimental variables were related todepth of cut and pocket geometry. Statistical analysis was carried out in order to develop mathematical models which include process variable interactions and quadratic terms. This led to models with high correlation and prediction power which allow a better understanding of the process and can form the base for further process optimisation. The models were validated with additional experiments and showed good agreement with the water-jet system. The results showed that water pressure has a non-linear behaviour and is of paramount importance for controlling the depth of cut and geometrical errors. Additionally, nozzle diameter and the interaction between feed rate and abrasive mass flow are critical factors affecting the depth of cut.

Multiresponse optimization based on statistical response surface methodology and desirability function for the production of particleboard

It is very difficult to determine the actual level of process parameters responsible for the quality production of particleboard due to the high degree of process variable interactions and lack of robust methodology for optimization. In this study, an attempt was made to optimize the process parameters of particleboard production by using multi-response optimization process. Plackett–Burman factorial design was first employed to eliminate some factors from selected seven important parameters: flake thickness, flake length, dried chips moisture content (MC%), amount of adhesive, pressing time, pressure, and press temperature. By using this screening procedure, three important factors: flake thickness, dried chips moisture content and press temperature were found to have significant effect on particleboard properties. Afterwards, Box–Behnken design was performed as response surface methodology (RSM) with desirability functions to attain the optimal flake thickness, MC% and press temperature that affect modulus of rapture (MOR) and modulus of elasticity (MOE) of particleboard production. The optimized parameters for maximum MOR and MOE determined were found to be: flake thickness, 0.15mm; press temperature, 182°C; and dried chip MC% 3.5. Finally, a confirmation study was executed by using optimized levels of parameters which showed well response to the predicted model.

Strategies for developing design spaces for viral clearance by anion exchange chromatography during monoclonal antibody production

The quality-by-design (QbD) regulatory initiative promotes the development of process design spaces describing the multidimensional effects and interactions of process variables on critical quality attributes of therapeutic products. However, because of the complex nature of production processes, strategies must be devised to provide for design space development with reasonable allocation of resources while maintaining highly dependable results. Here, we discuss strategies for the determination of design spaces for viral clearance by anion exchange chromatography (AEX) during purification of monoclonal antibodies. We developed a risk assessment for AEX using a formalized method and applying previous knowledge of the effects of certain variables and the mechanism of action for virus removal by this process. We then use design-of-experiments (DOE) concepts to perform a highly fractionated factorial experiment and show that varying many process parameters simultaneously over wide ranges does not affect the ability of the AEX process to remove endogenous retrovirus-like particles from CHO-cell derived feedstocks. Finally, we performed a full factorial design and observed that a high degree of viral clearance was obtained for three different model viruses when the most significant process parameters were varied over ranges relevant to typical manufacturing processes. These experiments indicate the robust nature of viral clearance by the AEX process as well as the design space where removal of viral impurities and contaminants can be assured. In addition, the concepts and methodology presented here provides a general approach for the development of design spaces to assure that quality of biotherapeutic products is maintained.

Development of Cationic Dyeable Polyamide Substrates by Pretreatment with Synthetic Tanning Agent: Statistical Optimization and Analysis

Design of experiments (DoE) concept was successfully applied to determine the optimum processing conditions that yield maximum % exhaustion for berberine interaction with synthetic tanning agent pretreated polyamide substrates. The potential of synthetic tanning agent to provide anionic sites on the polyamide for berberine interaction which is cationic in nature was tested to increase the % exhaustion of berberine in this article. Experiments were designed according to Central Composite Rotatable Design (CCRD). The three factors for synthetic tanning agent pretreatment and two factors for berberine interaction each at five different levels, including central and axial points were considered. Experiments were conducted in a laboratory scale infra-red treatment instrument according to CCRD. For each response, second order polynomial models were developed using multiple linear regression analysis incorporating linear, interactions and squared effects of all variables and then optimized. The significance of the mathematical model developed was ascertained using Excel regression (solver) analysis module. Analysis of variance (ANOVA) was performed to check the adequacy and accuracy of the fitted models. The response surfaces and contour maps showing the interaction of process variables were constructed. Applying Monte Carlo simulation, response surface and contour plots, optimum operating conditions were found and at this optimum point, % exhaustion of 81% and 74% respectively for synthetic tanning agent pretreatment and berberine interaction were observed and subsequently the results were experimentally investigated.

OPTIMIZATION OF MUCILAGE EXTRACTION FROM QODUME SHIRAZI SEED (ALYSSUM HOMOLOCARPUM) USING RESPONSE SURFACE METHODOLOGY

ABSTRACT Response surface methodology was used to determine the optimum processing conditions that yield maximum apparent viscosity and extraction yield and consistency coefficient with minimum protein content and flow behavior index during extraction of Qodume Shirazi seed gum. Extraction temperature (25–85C), pH (4–10) and water : seed (20:1–60:1) were the factors investigated. Experiments were designed according to Central Composite Face Center Design with these three factors, including central and axial points. The response surfaces showing the interaction of process variables were constructed. Solution with 3% concentration of each gum with different extraction methods were made to evaluate the flow properties of gum extracted from Qodume seeds. The Power‐law model was successfully applied to fit the shear stress versus shear rate data of gum solution. The flow behavior indices, n, varied in the range of 0.25–0.41. The consistency coefficients, k, were in the range of 5.5–8.62 Pa·sn. Applying desirability function method, optimum operating conditions were found to be extraction temperature of 36.3C, pH of 4 and water : seed of 40:1. At this optimum point, apparent viscosity, extraction yield and protein content, consistency coefficient, flow behavior index were found to be 855.9 (mPa·s), 287.3 (g/kg), 1.27 (%), 8.27 (Pa·sn) and 0.29, respectively.PRACTICAL APPLICATIONSGrowing use of hydrocolloids in food industries has brought about the need for new sources of these products. Therefore, there could be a substantial market for new source of produced gum. The aim of the present paper was to choose a suitable new source for extracting polysaccharides. Qodume Shirazi is a medicinal seed grown in the Middle East that produces a high amount of mucilage. Thus we optimized the best method for extraction of mucilage from this seed, which is important for producing gum from Qodume Shirazi and assessed the flow behavior of the gum.

Balanced, Nearly Optimal Mixture Experiments for Models with Interactions with Process Variables

In mixture experiments, the settings of the predictor variables are limited by the fact that the ingredients are dependent. There may also be other, non-mixture, variables (process variables) to consider. Here, designs are considered for two types of second-order models in mixture and process variables, including certain mixture/process interactions. Several new balanced D-optimal (or nearly D-optimal) designs are proposed and are compared with quasi D-optimal designs and other balanced designs previously suggested. The properties of these new balanced designs are examined for the extended model with linear mixture by second-order process variable interactions; the designs are either D-optimal or nearly D-optimal and have diagonally partitioned information matrices, simplifying the model building process. An example from the bread industry illustrates the value of such designs.

The optimization of Cr(VI) reduction and removal by electrocoagulation using response surface methodology

In this study Response Surface Methodology (RSM) was employed to investigate the effects of different operating conditions on the removal of hexavalent chromium (Cr(VI)) by the electrocoagulation with stainless steel electrodes. Central Composite Design (CCD) was used for the optimization of the electrocoagulation process and to evaluate the effects and interactions of process variables: applied electric current, electrolyte concentration and application time on the removal of Cr(VI). A sample of metal finishing industry wastewater having a high Cr(VI) concentration of 1470 mg/L was used in the experimental study. The optimum conditions for complete (100%) Cr(VI) removal were established as 7.4 A applied electric current, 33.6 mM electrolyte (NaCl) concentration and 70 min application time. The amount of sludge produced under the conditions optimized based on the results from the model was lower than the amount generated by chemical treatment with FeSO 4·7H 2O and non-hazardous in nature.

Optimization of osmotic dehydration of potato using response surface methodology

Response surface methodology was used to determine the optimum processing conditions that yield maximum water loss and weight reduction and minimum solid gain and water activity during osmotic dehydration of potatoes. Temperature (20–60 °C), processing time (0.5–8 h), sucrose (40–60% w/w) and salt (0–15% w/w) concentrations were the factors investigated with respect to water loss (WL), solid gain (SG), weight reduction (WR) and water activity ( a w). Experiments were designed according to Central Composite Rotatable Design with these four factors each at five different levels, including central and axial points. Experiments were conducted in a shaker (Thermoshake-Gerthardt) with constant agitation of 200 rpm and solution to sample ratio of 5/1 (w/w). With respect to water loss, solid gain, weight reduction and water activity, both linear and quadratic effects of four variables were found to be significant. For each response, second order polynomial models were developed using multiple linear regression analysis. Analysis of variance (ANOVA) was performed to check the adequacy and accuracy of the fitted models. The response surfaces and contour maps showing the interaction of process variables were constructed. Applying desirability function method, optimum operating conditions were found to be temperature of 22 °C, sucrose concentration of 54.5%, salt concentration of 14% and treatment time of 329 min. At this optimum point, water loss, solid gain, weight reduction and water activity were found to be 59.1 (g/100 g initial sample), 6.0 (g/100 g initial sample), 52.9 (g/100 g initial sample) and 0.785, respectively.

Predictive Models of Web-to-Roller Traction

We studied the traction developed between a thin, flexible web and a rotating circumferentially grooved cylindrical roller. We have developed a new two-dimensional analytic model that couples air film pressure, web deflection, and asperity contact to predict traction for circumferentially grooved rollers with arbitrary wrap angles. The entrance effects are incorporated into our new traction model by adapting the squeeze film concept using the distance from the entrance as a surrogate for time. We have verified this model experimentally on a series of 14 rollers and 19 webs. We tested both nongrooved and circumferentially grooved rollers. We showed experimentally that rough, ungrooved rollers that have their low areas unconnected produce significantly lower traction and do not fit the model introduced here. Such rollers should be avoided where traction is important. We introduce dimensionless groups that the roller designer can use to quantitatively assess the interactions of process variables (e.g., speed, tension, etc.) with design variables (e.g., groove depth, groove pitch, roughness, etc.) over the full range of practical wrap angles.

Temporal interaction of process variables in psychotherapy

A sample of 91 courses of dyadic psychotherapy using different treatment modalities was analyzed in order to study session-by-session dynamics. The process data consisted of therapist and patient session reports and therapy outcome was evaluated by pre-post questionnaires and direct measures of change. After data reduction by principal component analysis, linear time series models of the resulting factors were computed to describe the prototypical dynamical patterns of the sample and of the modality subsamples (cognitive-behavioral, client-centered, schema-theoretical psychotherapy). It was found that the factor of Patient's Sense of Self-Efficacy/Morale governed the observed dynamics of the sample, whereas the therapeutic bond factors did have less impact on the dynamics. The dynamical patterns of client-centered therapies differed from other modalities. The dynamics-outcome findings showed that direct measures of change were associated with a specific process pattern in which the patient's sense of self-efficacy was supported by other process variables.

Interaction of process variables with the fracture behavior of amorphous polystyrene during attrition

AbstractThis study investigates the fracture of oriented general‐purpose polystyrene. Specimen microstructure was controlled using an extrusion‐sheeting technique where draw ratio, polymer melt temperature, cooling roll temperature, and nip roll pressure changed according to a designed experiment. Sharp‐notched tension results display a 4X difference in longitudinal vs. transverse specimen values. Shrinkage measurements show contraction in the machine direction amplifies with increasing draw ratio. Craze formation is visible only in those specimens tested in the longitudinal direction. Fracture mechanisms have strong orientation dependence and the extrusion‐sheeting process produces an ideal system to study the effect on attrition. Comminution studies illustrate draw ratio has an effect on the final median particle size and width distribution of the powder. Increasing the draw ratio reduces the volume median particle size and minimizes the formation of fine particles. A monotonic fracture mechanism was initially considered but rejected in favor of a low cycle fatigue model based on estimates of fracture strength.

On the difficulties of implementing particle size control in particulate processes

This paper presents an overview of the difficulties in implementing particle size control in particulate processes. Such difficulties are mostly related to the complex interactions of process variables on particle size. Some ideas are given on the use of existing measuring devices and controlling actuating mechanisms in particulate processes. During recent years rapid developments of both devices and techniques have emerged that allow the control of one or two size variables with very good economic results.

An Analysis of Factors Affecting Pull Force for the Pultrusion of Graphite/Epoxy Composites

The influence of process parameter settings on the pull force required for the pultrusion of two epoxy resin systems reinforced with unidirectional graphite fiber was investigated. Experiments were conducted using the Shell EPON 9310/9360/537 epoxy resin system and the Shell EPON 9420/9470/537 epoxy resin system. Five independent factors—fiber volume, line speed, die zone I temperature, die zone 2 temperature, and die zone 3 temperature—were examined in each study. Regression analysis was used to iden tify the factors and factor interactions that influence the pull force required for the pultru sion of each resin system and to develop mathematical models to describe the pull force. The models indicated that process variable interactions were especially significant. Re sponse surface methods were used to illustrate the nature of the interactions. Additional statistical techniques were employed to investigate the influence of resin viscosity on the pull force and the influence of pull force on the four-point flexural strength of the com posites produced.

Consolidation of Continuous Fiber, Intermetallic-Matrix Composites

ABSTRACTProcessing routes for fabrication of continuous fiber, intermetallic-matrix composites are reviewed. These methods include conventional and isostatic hot pressing of layups of matrix material (e.g. foil or powder cloth) and fiber mats; consolidation of monotapes made by techniques such as arc, plasma, vapor, or electron beam deposition or tape casting; and liquid metal infiltration-base methods. The advantages and disadvantages of the various methods are discussed. Particular attention is focussed on HIP consolidation via foil-fiber-foil techniques. Process modeling techniques to assess the effects of pressure, temperature, and time on consolidation behavior are described. By this means, maps to delineate the interaction of process variables in such methods can be developed and applied for process optimization.