Effect Of Different Process Parameters Research Articles

Experimental and mathematical study of air gap membrane distillation for aqueous HCl azeotropic separation

AbstractBACKGROUNDIn the present study, the feasibility of air gap membrane distillation (AGMD) process is investigated for breaking an azeotropic mixture. A test cell AGMD module with hydrophobic PTFE membrane was fabricated and HCl/H2O azeotrope (20.2 wt% HCl) was taken as feed. A mathematical model based on Stefan diffusion multicomponent molecular‐Knudsen mass transfer approach has been developed and validated with experimental data. The effects of different process parameters on total permeate flux, on selectivity and on breaking an HCl/H2O azeotrope mixture also have been studied. The feed side membrane surface temperature and membrane side condensing surface temperature were estimated by CFD modelling.RESULTSThe HCl selectivity obtained in the permeate was <1, which indicates that permeate flux is leveraged with water and a higher HCl concentration in the retentate was achieved relative to the permeate. The permeate flux decreased from 36 to 17 kg m−2 h−1 upon increasing the air gap from 3 mm to 11 mm at 50 °C feed temperature. The permeate flux increased from 4 to 28.5 kg m−2 h−1 upon increasing the feed temperature from 30 to 50 °C at 5 mm air gap.CONCLUSIONWith azeotropic feed, the maximum concentration of HCl achieved in the retentate was 30.8 wt% HCl (i.e. a hyperazeotropic solution) and in permeate was found to be 15.29 wt% HCl (i.e. hypoazeotropic solution). This indicates a strong possibility of using AGMD for azeotropic mixture separation. It also was observed that the permeate flux is affected mainly by feed temperature and air gap width. © 2018 Society of Chemical Industry

Structural investigation of spunlace nonwoven

PurposeSpunlacing is a promising nonwoven technology for the production of fabric with good handle and better structural integrity. Structural parameters such as pore size, thickness and number of binding point/entanglement between fibres are decisive for good mechanical and comfort properties of nonwoven fabrics. This study aims to focus on the effect of different process parameters on the structural change in spunlace fabrics.Design/methodology/approachSpunlacing is purely a mechanical bonding technology where high-speed jets of water strike a web to entangle the fibres. Different spunlace nonwoven structures were produced by varying processing parameters such as waterjet pressure, delivery speed, web mass and web composition as per four-factor, three-level Box–Behnken design. The effect of these parameters on the structural arrangement was studied using scanning electron microscopy. An attempt has also been made to study the changes in pore geometry and thickness of the fabrics by using response surface methodology with backward elimination.FindingsSignificant structural changes were observed with variation in water pressure, web mass and web composition. The test results showed that fabric produced at higher waterjet pressure has lower mean pore diameter and lower thickness. The variation in mean pore diameter and mean thickness due to waterjet pressure is around 26 and 34 per cent, respectively, at 95 per cent significance level. The web composition and web mass also significantly influence the mean pore diameter and thickness at 95 per cent significance level. There is a strong positive correlation (r = 0.523) between mean air permeability and mean pore diameter of fabric, and this correlation is significantly linear. A strong negative correlation (r = −0.627) is found between weight and air permeability of fabric.Research limitations/implicationsThe delivery speed failed to show any significant effect; this is in contrary to the general expectation.Originality/valueThe effect of concurrent variation in waterjet pressure, web mass, delivery speed and web composition on the structure of spunlace nonwoven is studied, which was not reported in the literature. The effect of web composition on pore diameter of spunlace nonwoven is interesting finding. This study is expected to help in designing the spunlace nonwoven as per end uses and specifically for apparel application.

Predictive Simulation of Plastic Processing of Welded Stainless Steel Pipes

Metal forming is the most used technique to manufacture complex geometry pieces in the most efficient way, and the technological progress related to the various application fields requires increasingly higher quality standards. In order to achieve such a requirement, people are forced to perform quality and compliance tests finalized to guarantee that these standards are met; this often implies a waste of material and economic resources. In the case of welded stainless steel pipes, several critical points affecting the general trend of subsequent machining need to be taken into account. In this framework, the aim of the paper is to study the effects of different process parameters and geometrical characteristics on various members of the stainless steel family during finite elements method (FEM) simulations. The analysis of the simulation outputs, such as stress, strain, and thickness, is reported through mappings, in order to evaluate their variation, caused by the variation of the simulation input parameters. The feasibility of the simulated process is evaluated through the use of forming limit diagrams (FLD). An experimental validation of the model is performed by comparison with real cases. Major parameters that mainly guide the outcome of the simulations are highlighted.

Microencapsulation of energy conversion photochromic materials with epoxy resin shell by interfacial polymerization

In this study, a novel type of photochromic spirooxazine microcapsule was prepared by interfacial polymerization between epoxy resin and polyamine compound. The effects of different process parameters on the formation, microstructure and performance of microcapsules, such as curing reaction temperature, emulsification shear rate and the addition of silica nanoparticles were studied in this paper. The morphology, microstructure, diameter and distribution, as well as the thermal stability of microencapsulated photochromic spirooxazine were also investigated by field emission scanning electron microscope, laser particle size analyzer and thermogravimetric analysis systematically. In addition, the photochromic performance of microcapsule was studied as well.

RSM based optimization of PEG assisted ionic liquid pretreatment of sugarcane bagasse for enhanced bioethanol production: Effect of process parameters

Production of bioethanol from lignocelluloses is highly dependent on pretreatment process. Therefore, a better understanding of this process is an essential prerequisite to consider the whole bioethanol production from lignocelluloses in a cost and energy efficient way. The first step in performing the pretreatment is to discover the effects of different process parameters on various chemical features of the lignocelluloses. In order to achieve this aim, response surface methodology (RSM) was chosen to assess the exact impact of variables including temperature, polyethylene glycol (PEG) concentration and time on glucan, xylan and acid insoluble lignin contents as responses, also to optimize the pretreatment process to finally achieve higher bioethanol production yields. 1-butyl-3-methylimidazolium chloride (BMIMCl) and PEG in the concentration range of 1–5 (%w/w) were used as pretreatment agents. Temperature and time levels of 100–160 °C and 60–120 min were considered for experimental design, respectively. For further understanding of the effects of pretreatment on lignocelluloses, structural features examined by FT-IR, SEM and XRD analysis, in addition, enzymatic hydrolysis and fermentation were implemented on the samples pretreated in optimum conditions. The optimum pretreatment condition is 154.6 °C, 60 min and 5 (%w/w) of PEG concentration which resulted to the high enzymatic conversion and bioethanol production.

Optimization of settling characteristics of coal fine tailings with an anionic polyacrylamide using response surface methodology

ABSTRACT The study was carried out to investigate the effect of different process parameters on the settling performance of coal fine tailings collected from a coal preparation plant in India. Response surface approach was followed to assess the effect of pulp density, pH, and flocculant dosage on settling performance. The Box–Behnken design model predicted responses were obtained with coefficient of determination R2 as 0.99 and 0.98 for settling rate and turbidity, respectively. The optimum condition established for settling rate and turbidity was found to be at pulp density – 6% w/w, pH –​ 7.84, and flocculant dosage –​ 14.58 gpt with predicted settling rate and turbidity as 194.97 mm/min and 22.56 NTU, respectively, with the desirability of 90.4%.

Application of response surface methodology to analyze the effect of selective laser sintering parameters on dimensional accuracy

This paper investigates the dimensional accuracy of selective laser sintered parts considering the effect of different process parameters, while processing duraform polyamide as the work material. The correlation between different process parameters and dimensional accuracy (performance measures) was established by developing mathematical models. The correlation coefficients (R2 = 0.860288), approximately close to 0.9, showed that the generated models are reliable and effectively predict the response within the domain of the selected process parameters. Analysis of variance was employed to check the adequacy of the developed models and also to determine the significance of the parameters. It was observed that dimensional accuracy increases with the increase in laser power, bed temperature and scan count. Scan spacing is found to be the most significant parameter; dimensional accuracy decreases with the increase in scan spacing. Optimization has been carried out with the use of response surface methodology and a desirable functional approach. Subsequently, the optimized parts were obtained and presented.

Parametric optimization of multiple quality characteristics in laser cutting of Inconel-718 by using hybrid approach of multiple regression analysis and genetic algorithm

Inconel-718 has found high demand in different industries due to their superior mechanical properties. The traditional cutting methods are facing difficulties for cutting these alloys due to their low thermal potential, lower elasticity and high chemical compatibility at inflated temperature. The challenges of machining and/or finishing of unusual shapes and/or sizes in these materials have also faced by traditional machining. Laser beam cutting may be applied for the miniaturization and ultra-precision cutting and/or finishing by appropriate control of different process parameter. This paper present multi-objective optimization the kerf deviation, kerf width and kerf taper in the laser cutting of Incone-718 sheet. The second order regression models have been developed for different quality characteristics by using the experimental data obtained through experimentation. The regression models have been used as objective function for multi-objective optimization based on the hybrid approach of multiple regression analysis and genetic algorithm. The comparison of optimization results to experimental results shows an improvement of 88%, 10.63% and 42.15% in kerf deviation, kerf width and kerf taper, respectively. Finally, the effects of different process parameters on quality characteristics have also been discussed.

Experimental optimization and reactor simulation of coal-derived naphtha reforming over Pt–Re/γ-Al2O3 using design of experiment and response surface methodology

In this study, the effects of different process parameters on the yield of aromatics (YA) and the yield of C5+ (YC5+) were studied through catalytic reforming experiments of coal-derived naphtha (CDN). First, the optimum process parameters of CDN catalytic reforming were weighted average inlet temperature (WAIT) for (500–520 °C), pressure (P) for (1.2–1.6 MPa), liquid hourly space velocity (LHSV) for (2.0–3.0 h−1), hydrogen–oil volume ratio (VH/VO) for (600:1). The optimum conditions were WAIT 516 °C, P 1.4 MPa, LHSV 2.3 h−1 and the predicted value of YA was 79.81%. The effect of each factor on YA was presented as follows: P > LHSV > WAIT. Compared to the catalytic reforming of petroleum-based naphtha, CDN catalytic reforming not only achieves higher YC5+ while achieving higher YA, but also obtains higher yield of benzene–toluene–xylene (YBTX, 60%). Second, the 17-lumped kinetic model of CDN semi-regenerative catalytic reforming reactor was established, and the model parameters of kinetic model were estimated and validated by Broyden–Fletcher–Goldfarb–Shanno algorithm. The results show that the simulation model is accurate, reliable and has good predictive ability. Third, the change regulation of reactants and temperature in the reforming reactor along the catalyst bed were simulated by using the 17-lumped kinetic model under specific operating conditions.

Subsurface Damage in Polishing Process of Silicon Carbide Ceramic.

Subsurface damage (SSD) in the polishing process of silicon carbide (SiC) ceramic presents one of the most significant challenges for practical applications. In this study, the theoretical models of SSD depth are established on the basis of the material removal mechanism and indentation fracture mechanics in the SiC ceramic polishing process. In addition, the three-dimensional (3D) models of single grit polishing are also developed by using the finite element simulation; thereby, the dynamic effects of different process parameters on SSD depth are analyzed. The results demonstrate that the material removal was mainly in brittle mode when the cutting depth was larger than the critical depth of the brittle material. The SSD depth increased as the polishing depth and abrasive grain size increased, and decreased with respect to the increase in polishing speed. The experimental results suggested a good agreement with the theoretical simulation results in terms of SSD depth as a function of polishing depth, spindle speed, and abrasive grain size. This study provides a mechanistic insight into the dependence of SSD on key operational parameters in the polishing process of SiC ceramic.

Influence of the processing parameters on needleless electrospinning from double ring slits spinneret using response surface methodology

ABSTRACTNeedleless electrospinning technology was an effective processing method which can fabricate large scale nanofibers. We first developed a novel double rings slit spinneret to overcome the shortcomings of current needleless electrospinning spinnerets. The solution of the flow rate was controlled accurately by peristaltic control pump. Response surface methodology was adopted to investigate the influence of the processing parameters on the morphology and diameter of nanofibers. The main spinning processing parameters comprised solution concentration, applied voltage, collection distance and solution flow rate. The analysis of variance was used to evaluate response surface reduced quadratic model for nanofiber diameter. The linear and quadratic coefficients were obtained. The morphology of nanofibers was observed by scanning electron microscopy. Effects of different processing parameters on the nanofiber mean diameter have been discussed. Predicated values have a good agreement with actual values for nanofiber diameter. Actual nanofiber diameter ranges from129.15 to 404.70 nm with different process parameters. Mechanical properties of nanofiber membrane have been investigated. High quality and high throughout nanofiber could be continuously produced. This novel needleless electrospinning spinneret has a great potential for large scale nanofibers production to promote electrospinning technology development. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46407.

Grey relational analysis-based genetic algorithm optimization of electrical discharge drilling of Nimonic-90 superalloy

Nickel-based superalloys are being increasingly used in aerospace, automotive industries due to their excellent thermo-mechanical properties. These applications require complex shapes and profiles which may not be obtained by conventional machining processes. These materials are also known as difficult-to-machine due to their excellent thermo-mechanical properties. The electrical discharge drilling proves its suitability in the precision drilling of superalloys. During, the electrical discharge drilling of these materials, hole taper, hole circularity and hole dilation are key attributes which influence the drilled hole quality. In this research paper, the experiments have been conducted by L27 orthogonal array and this experimental data have been utilized for developing the models of different geometrical quality characteristics such as hole circularity, hole taper and hole dilation. Further, a new hybrid approach grey relational analysis-based genetic algorithm has been proposed and implemented for the multi-objective optimization of different quality characteristics. The effects of different process parameters on various geometrical quality characteristics have also been discussed. Finally, the confirmation tests have been performed to validate the predicted results obtained by the proposed hybrid methodology to the experimental results. It has been observed by the comparison results that the machining performance in the electrical discharge drilling process has been remarkably improved through proposed approach.

Parametric Finite Elements Model of SLM Additive Manufacturing process

An obstacle to the diffusion of additive technology is the difficulty of predicting the residual stresses introduced during the fabrication process. This problem has a considerable practical interest as evidenced by the abundant literature on residual stresses and distortion induced by the SLM (Selective Laser Melting) and EBAM (Electron Beam Additive Manufacturing).The purpose of this paper is to evaluate the effect of different process parameters on the heat distribution and residual stresses in components made with SLM technique. Three aspects are developed and illustrated: a) thermomechanical modeling of the growth process, based on Finite Elements (FE), which considers changes in the behavior of the material (powder→liquid→solid) through the finite element “birth” and “death” technique that enables the progressive activation of the elements as the component grows; b) sensitivity analysis of the model to the physical characteristics of the material (conductivity, specific heat capacity, Young’s modulus). This is an important aspect allowing to focus on the most significant parameters to be determined experimentally with high reliability; c) evaluation of the effects of different process parameters (laser power, scan speed, overlap between adjacent paths) on the process.The article illustrates the theoretical thermal model and the detail of the strategy used in the FE analysis. The most influential characteristics of the material are highlighted and, finally, general criteria for choosing the optimal combination of process parameters to limit the residual stresses are provided.

Study on erosion wear of steels under varying abrasive jet

Erosion is one of the frequently occurring wear of aerospace, power plant, surface vehicles and ship components. Wear is detrimental that reduces service life of the engineering components. An abrasive jet system can provide the means of erosion by supplying high velocity abrasive jet towards the materials from which components are made. On way of investigating the sustainability of engineering materials against erosion, mild steel and austenitic stainless steel had been being targeted by an abrasive jet by varying different process parameters. The rate of erosion of mild steel and austenitic stainless steel was measured under various process conditions. The effect of different process parameters on crater depth was also investigated

Optimization of Machining Parameter during the Laser Cutting of Inconel-718 Sheet Using Regression Analysis based Particle Swarm Optimization Method

This experimental work describes the utilization of a hybrid approach of regression modeling and particle swarm optimization (PSO) for optimizing the process parameters during the laser cutting of the Inconel-718 sheet. The experiments have been performed by using four machining parameters such as assist gas pressure, standoff distance, cutting speed and laser power. The kerf width and kerf taper are used as an output quality characteristic. The experiments have been performed by using well planned orthogonal array L27.The second order regression models have been developed for kerf width and kerf taper by using the experimental data. The developed second order regression models have been utilized in optimization by particle swarm optimization. The comparison of the experimental result with optimum results confirms that the individual improvement in output quality characteristics kerf width and kerf taper is approximate 10% and 57%, respectively. The overall improvement of 46% has been observed during the optimization. Finally, the effects of different process parameters on different performances have also been discussed. The parametric effect analysis shows that minimum kerf taper may be obtained at lowest values of laser power and middle values of standoff distance

A Numerical Study on Tube Hydroforming Process to optimize the Process Parameters by Taguchi Method

Tube hydroforming (THF) is an essential manufacturing technique in the modern days and in general, THF has become a convenient method for built-up complex automobile parts. This process depends mainly on the process parameters like internal pressure, axial feeds, material properties, and other processing conditions. Design by simulation has usually been a trial and error process, where the purpose is to find a feasible and cost effective process to produce a defect free product by altering process parameters. In this study tools required for the tube hydroforming process has modeled in the cad package CATIA V5 and these are imported into the commercial finite element code PAM-STAMP 2G for conducting the simulations. The effects of different process parameters have been investigated by numerical analysis and also the Taguchi Technique for optimization on Aluminum alloy Al99. The optimum conditions have been determined based on their effect on bulge height and thinning distribution of the tube material. Three important process parameters i.e., Internal Pressure, Axial feed and Frictional Coefficient were investigated. Finally, the mutual effect on Aforesaid process parameters on bulge height and thinning distribution were studied.

Experimental investigations on entrained flow gasification of Torrefied Karanja Press Seed Cake

Experimental work on oxygen–steam based entrained flow gasification of Torrefied Karanja Press Seed Cake (TKPSC) has been carried out in order to evaluate the effect of temperature, Equivalence Ratio (ER), Steam to Biomass Ratio (SBR) and Particle Size (Dp) on the syngas composition also, Lower Heating Value (LHV), Cold Gas Efficiency (CGE) and Carbon Conversion (CC). The experimental work was conducted in an entrained flow gasification unit of 1 kg/h federate designed and installed at Indian Institute of Chemical Technology, India. In this work, the temperature was varied from 600 °C to 1100 °C. The ER and SBR values were varied between 0.1 and 1 while, Dp was changed from 0.5 to 3.0 mm. The aim here was to understand the effect of different process parameters and derive relative optimum operating conditions for the entrained flow gasification of the TKPSC. The results obtained show that operating conditions such as temperature of 1100 °C, ER of 0.3, SBR of 0.4 and 0.5 mm Dp were found to be the most relative optimum operating parameters. The highest values of LHV around ∼12 MJ/Nm3, CGE around ∼90% and CC up to 98% were obtained for TKPSC. These values are in agreement with the results reported in the literature on the other biomass waste materials that pocess similar properties to TKPSC.

Novel synthesis of Ru/OMS catalyst by solvent-free method: Selective hydrogenation of levulinic acid to γ-valerolactone in aqueous medium and kinetic modelling

γ-Valerolactone (GVL) is an important bio-derived molecule that could be used for the sustainable production of value-added chemicals and fuels. It is mainly synthesized by hydrogenation of levulinic acid by using supported ruthenium catalyst. Here we are reporting the synthesis of ruthenium supported on manganese oxide octahedral molecular sieve (OMS-2) catalyst prepared by different methods. Three different methods, i.e. reflux, hydrothermal and solventless protocols were used for the preparation of OMS-2. The prepared catalysts were used for the selective hydrogenation of biomass-derived levulinic acid (LA) to GVL using molecular hydrogen in water. Solventless synthesized OMS (OMS-2S) is energy efficient, rapid and economical way of synthesis. Among three different catalysts, Ru supported on solventless OMS-2 i.e. 1 wt% Ru/OMS-2S catalyst showed LA conversion of 99.9% and yield of 99.8% towards GVL in 1 h with the overall turnover frequency of 0.95 s−1 at mild conditions (100 °C, 30 atm H2). Different OMS-2 supported Ru catalysts showed a very high turnover frequency in comparison with those reported in literature for the synthesis of GVL. The specific textural and chemical properties of catalysts were characterized by various techniques. Moreover, 1 wt% Ru/OMS-2S catalyst was reusable up to four times without significant loss of activity and was very stable. By studying the effects of different process parameters, a kinetic model was developed based on LHHW type of mechanism. The apparent activation energy for LA hydrogenation to GVL is 11.75 kcal/mol.

Effect of machining parameter on femtosecond laser drilling processing on SiC/SiC composites

Due to the unique properties of femtosecond laser in precision machining, femtosecond laser was utilized for irradiation on SiC/SiC composites. Effects of different processing parameters, including the spot overlap ratio, helical line overlap ratio, laser processing power, as well as processing steps, were discussed in detail. The results indicated that the parameters above had significant effect on machining of SiC/SiC composites. The surface morphology and geometry of the micro-holes were investigated under different parameters, and the corresponding formation mechanism was discussed in detail. It was believed that both the spot and helical line overlap ratio had great effect on the quality of the micro-holes and would be responsible to the depth of micro-holes. Besides, it is indicated that the higher processing power will lead to a better quality of surface morphology and machining results. In micro-hole drilling process, debris and fragments were observed within the micro-holes, and XPS analysis showed that there existed Si-O bonds and Si-C bonds, indicating that the oxidation during processing was incomplete. In addition, the effect of feeding speeds on geometry and depth of the micro-holes were discussed as well.

Synthesis, characterization and antibacterial activity of juglone encapsulated PLGA nanoparticles.

The aim of the study was to examine the effect of different process parameters which including; initial juglone amount, initial poly(d,l-lactide co-glycolide) amount, polyvinyl alcohol volume and polyvinyl alcohol concentration on encapsulation of juglone to poly(d,l-lactide co-glycolide) nanoparticles. The synthesized nanoparticle formulations were analyzed for reaction yield, encapsulation efficiency, particle size, polydispersity, zeta potential and juglone release. In conjunction with the highest encapsulation rate, the highest amount of juglone release was obtained for F4 formulation, which has 281·8nm particle size, 0·217 polydispersity index, and -19·55 mV zeta potential. After the detailed physicochemical characterization of this formulation, the four different kinetic models were used and it was found that juglone release mechanism controlled by Fickian diffusion method. According to antimicrobial activity results, minimal inhibitory concentration (MIC) values of both F4 and free juglone is higher for Gram negative bacteria than Gram positive bacteria. Inhibition zone diameters in the quantitative methods are found 15 and 16mm for Staphylococcus aureus, 9 and 7 mm for Bacillus cereus, respectively, for F4 and free juglone. Moreover, the MIC values for qualitative methods were found 31·5μgml-1 for two bacteria strains. It was found that the antibacterial activity of the juglone nanoparticles was higher and longer than the free juglone. Additionally, a similar antimicrobial effect with a lower juglone amount (obtained from controlled release study) indicates that nanoparticle formulation is more effective. The use of nanoparticle formulations of juglone in biological systems and applications could be more beneficial than its free form due to its toxicity.