Surface Plots Research Articles

Optimization, characterization, and GC-MS analysis of CSOME produced using alkali catalyzed transesterification

Biodiesel (methyl ester) was synthesized from cottonseed oil (CSO) with methanol in the presence of an alkali catalyst (KOH) through the transesterification method. Response surface methodology (RSM) optimized the methyl ester synthesis process. The experimental design matrix was arranged using the Box-Behnken Design (BBD) of RSM. The optimization of methyl ester was achieved by varying variables such as the methanol to CSO ratio, the concentration of the catalyst, and the reaction duration. A contour plot and a surface plot were generated to illustrate the impact of these variables on methyl ester synthesis. The biodiesel yield was modeled as a quadratic equation through RSM analysis, with a coefficient of determination (R2) and adjusted R2 of 0.97 and 0.968, respectively. The optimized CSOME yield (95.04%) was numerically gained at a 1:6 methanol to CSO ratio, a reaction duration of 52.2 min, and a 0.985 wt% catalyst concentration. Based on these parameters, a 94.80% CSOME yield was experimentally obtained. This shows that response surface methodology (RSM) is sufficient for optimizing methyl ester yield. The produced methyl ester was characterized to determine its physicochemical properties. Gas chromatography-mass spectrometry (GC-MS) analysis was used to identify the specific type and proportion of fatty acid esters present in the CSOME. The main types of fatty acids found in CSOME were methyl 9-cis 11-trans-octadecadienoate (C18:2), hexadecanoic acid methyl ester (C16:0), 11, 14-octadecadienoic acid methyl ester (C18:2), methyl 8, 9-octadecadienoate methyl ester (C18:2), and myristic acid methyl ester (C14:0).

An Optimization Study of Advanced Fenton Oxidation Methods (UV/Fenton–MW/Fenton) for Treatment of Real Epoxy Paint Wastewater

The use of various advanced oxidation methods in the treatment of wastewater has become the subject of many studies published in recent years. In particular, it is exceedingly significant to compare these treatment methods for industrial wastewater to reduce environmental effects and optimize plant operations and economics. The present study is the first to deal with the treatability of real epoxy paint wastewater (EPW) using MW- and UV-assisted Fenton processes within an optimization framework. A three-factor, three-level Box–Behnken experimental design combined with response surface methodology (RSM) was conducted for maximizing the chemical oxygen demand (COD) and color removal efficiencies of ultraviolet (UV)/Fenton and microwave (MW)/Fenton processes in the treatment of the real epoxy paint wastewater (EPW, initial COD = 4600 ± 90 mg/L, initial color = 114 ± 4 Pt-Co), based on 15 different experimental runs. Three independent variables (reaction time ranging from 20 to 60 min (UV) and from 5 to 15 min (MW), power ranging from 20 to 40 W (UV) and from 300 to 600 W (MW), and H2O2/Fe2+ ratio ranging from 0.2 to 0.6 (for both UV and MW)) were consecutively coded as A, B, and C at three levels (−1, 0, and 1), and four second-order polynomial regression equations were then derived to estimate the responses (COD and color removals) of two distinct systems. The significance of the independent model components and their interrelations were appraised by means of a variance analysis with 99% confidence limits (α = 0.01). The standardized differences of the independent variables and the consistency between the actual and predicted values were also investigated by preparing normal probability residual plots and experiment-model plots for all processes. The optimal operating conditions were attained by solving the quadratic regression models and analyzing the surface and contour plots. UV/Fenton and MW/Fenton processes, which constitute combined Fenton processes, were performed using advanced oxidation methods, while Fenton processes were utilized as the standard method for wastewater treatment. When UV/Fenton and MW/Fenton processes were applied separately, the COD removal efficiencies were determined to be 96.4% and 95.3%, respectively. For the color parameter, the removal efficiencies after the application of both processes were found to exceed 97.5%. While these efficiencies were achieved in 1 h with a 38 W UV unit, they were achieved in 15 min with a MW power of 570 W. According to the RSM-based regression analysis results, the R2 values for both processes were greater than 0.97 and p values were less than 0.003.

MHD second-grade nanofluid slip flow over a stretching sheet subject to activation energy, thermophoresis, and Brownian effects

In this work, the magnetohydrodynamic flow of two engine oil-based second-grade nanofluids Copper (Cu) and Titanium oxide (TiO 2) over a penetrable stretching sheet is studied. The flow, heat and mass transfer characteristics in the existence of activation energy, inclined magnetic field, Brownian diffusion, elastic deformation, and thermophoresis are examined. The coupled nonlinear model equations are formulated by implementing the Modified Buongiorno model and then are non-dimensionalized by the similarity transformation technique. The non-dimensional equations are simulated numerically using the bvp4c solver. Graphs are plotted to study the flow behaviour of nanofluid with the rate of entropy generation and Bejan number. The outcomes of skin friction coefficient, Nusselt number and Sherwood number are exhibited via surface plots. From the analysis, a higher inclination of the magnetic field decays the velocity and amplifies the temperature profiles. The heat transport rate diminishes with the Brownian diffusion, thermophoresis and elastic deformation parameters. The mass transport rate is accelerated due to the activation energy parameter. The entropy generation rate is enhanced with the Brinkman, Biot and local Reynolds numbers. Furthermore, it is seen that engine oil-based TiO 2 nanofluid has larger velocity, temperature and rate of entropy generation than engine oil-based Cu nanofluid. The current examination has applications in automobile radiators, microchips, biomedical engineering, and extraction of geothermal power.

Box-Behnken optimization of pin-on-disc wear test process parameters

The Full factorial and Box-Behnken Designs for determination of optimal values of wear rate using pin –on-disc wear test parameters have been successfully carried out. The parameters used are track diameter of the disc, mass difference of specimen before and after the test and speed of the disc. The mathematical model developed for the “smaller-the-better” wear rate response by the Full factorial and Box-Behnken Design methods were adjudged adequate with a pvalue of 0.025 and 0.046 respectively. Also, the adjusted R2 values of the Factorial and Box-Behnken Designs were determined to be 0.89 and 0.69 respectively. The statistical ANOVA analysis carried out on the Box-Behnken Design showed that the track diameter and the mass difference were significant with a p-value of 0.041 and 0.007 respectively. Contour plots and response surface plot developed for the factorial method and the Box-Behnken Design displayed appreciable level of similarity. It was noticed that a reduction of wear was occasioned by an increase in track diameter and speed of the disc.

Preparation, Optimization, and In-Vitro Release Study of Abemaciclib-Loaded Chitosan Nanocarrier as a New Approach for Breast Cancer Treatment

Abstract: Abemaciclib (Abm) is a CDK inhibitor that specifically targets the CDK4/6 cell cycle pathway and has potential anticancer activity. Unfortunately, it has a low solubility and dissolution rate. background: Abemaciclib Unfortunately, it has low solubility and dissolution rate. Aim: The aim of this study is to enhance the solubility of ABM by loading it onto a chitosan (CS) polymer. Method: Polymer nanoparticle (NP) and Abm-CSNPs nanocomposites were prepared. Minitab 18 software was used to design 18 run samples to study the effects of CS, tripolyphosphate, and pH as independent variables on the loading efficiency and particle size (dependent variable). The response surface methodology (RSM) was also used to determine how the variables affected the response. The graphical analysis used surface plots, main effects plots, contour plots, and interaction graphs. The study includes F values, P values, variance inflation factors (VIFs), adjusted sums of square (Adj SSs), adjusted mean squares (Adj MSs) and square error of the coefficient (SE Coef). The carriers and loaded samples were also examined using the results of tests, including Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Furthermore, the release of Abm from Abm-CSNPs nanocomposite was studied in vitro. Results: The results revealed an ability to produce particle sizes ranging from (168-192) nm and loading efficiencies from (56.7-62.1). Conclusion: Abm-CSNPs nanocomposite may be used as an alternative drug delivery system for Abm to increase the release time of Abm to 1400 minutes.

Abundant soliton solutions of the modified KdV-KP equation

The precise solutions of the (2+1)-dimensional modified KdV-KP equation are examined in this study. Three reliable methods, namely, the modified auxiliary equation scheme, extended rational sine–cosine methodology, and extended rational sinh–cosh technique, are utilized for the first time to extract multiple soliton solutions for the governing model. These types of solutions have applications in plasma, solid state, neuronal, biological production, and diffusion processes. Graphical simulations of the obtained solutions are included in the form of 3 dimensional surface plots to reveal their physical structure and dynamical features.

An experimental assessment of simultaneous reduction in vehicle tailpipe emissions employing desirability function analysis

In vehicles powered by fuel, the effort to minimize CO and HC emissions through various strategies leads to an increase in CO2, contributing to global warming. This study aimed to experimentally assess the simultaneous reduction of vehicle tailpipe emissions of CO, HC, and CO2 using desirability function analysis (DFA). On predetermined routes in Addis Ababa city, two vehicles were tested for on-road emissions at five various speeds and on five various road slopes using a portable emissions tester. Surface plots were used to display how the tailpipe emissions of CO2, CO, and HC vary with changes in vehicle speed and road gradient. The DFA results revealed that the optimal speed for simultaneous reduction of CO, HC, and CO2 emissions was 40 km/h on a flat route and 30 km/h on a 2-degree uphill, with composite desirability of 0.83 and 0.72, respectively. This study found that a speed of 30 km/h on a flat road increased CO2 by 2.82%, CO by 18.97%, and HC by 5.28% compared to an optimized vehicle speed of 40 km/h. On a 2-degree gradient, a vehicle traveling at 20 km/h exhibited a 4% increase in CO2 emissions, a 23.92% increase in CO emissions, and a 1.26% decrease in HC emissions compared to the optimized speed of 30 km/h. Adjusting speed limits according to road gradients is recommended to minimize vehicle tailpipe emissions simultaneously using DFA. This approach contributes to lowering air pollution by reducing pollutant emissions from vehicles through optimized speeds.

Comparative analysis and experimental exploration of the milling process in the machining of Inconel 825 material under MQL

ABSTRACT With the flood cooling technique approach, it is impossible to fulfill the concerned environmental regulations and increase productivity while machining material that is infamously tough to cut. To address the conscious environmental regulation in the metal cutting industry, an effect must be made to reduce the industry process impact on environmental pollution along with manufacturing process optimization. Therefore, an eco-friendly MQL technique was investigated associated with machinability characteristics and compared results with dry condition while end milling of Inconel 825 material. The results revealed that MQL significantly reduced cutting temperature (CT) and surface roughness (Ra) to maximum levels of 70% and 43%, respectively. Further, optimum conditions were found using Taguchi method under MQL cooling. Additionally, using 3D surface plots, the interaction impact of process parameter on “Ra” has been investigated. For end milling Inconel 825 material, the MQL machining method has been proven as the most feasible alternative over dry condition.

Some studies on optimization of process parameters for wire ARC additive manufacturing of Hastelloy C276 using GRA-GWO hybrid techniques

Wire arc additive manufacturing (WAAM) has become an inevitable manufacturing technology in the present decade. This article discusses optimizing process variables for fabricating Hastelloy C276 alloy via WAAM. The controlling parameters are gas flow rate (GFR), deposition speed, and welding current, while the depth of penetration, top reinforcement, and bead width are the output parameters considered for optimization. The magnitude of interaction effects between control parameters is equal to that of individual impact on the weld bead characteristics evident from analysis of variance results. Grey relational analysis revealed the optimal parameters (trial 1 with I = 120 A, S = 200 mm/min, GFR = 15 L/min) chosen through its robust optimization procedure. S/N ratio analysis revealed the most influencing parameters at the factor level (current level 1, speed level 1). The Grey Wolf optimizer (GWO) algorithm was used as a precision and confirmation experiment. The GWO optimization results further confirmed that the GFR of 15 L/min, speed of 200 mm/min, and current of 120 A were the optimized parameters used in this design space. Further, normal probability plots with minimal error of around 1% reinforce that the parameters chosen in this design space are well within the optimal limits. The surface plots reported the relationship and variation between control and resulting factors.

Significance of Inclined MHD on Hybrid Nanoliquid Flow in an Annulus Using Modified Buongiorno Model in the Presence of Two Different Heat Sources: Response Surface Methodology

In this modern fluid field technology, hybrid nanoliquid are of great interest to researchers because of their thermal properties which provide superior heat transfer improvements compared to nanoliquid. Thus, in this study, the heat and mass transport characteristics in a horizontal annular duct filled with the water-based Cu–Al2O3 hybrid nanoliquid is analyzed using the modified Buongiorno model (two-phase model). The two different heat sources namely, temperature-related heat source (THS) and exponential space-related heat source (ESHS) are analyzed in thermal analysis. An inclined magnetism and viscous dissipation aspects are also taken into account. The correlation for effective thermal conductivity and viscosity are modeled by utilizing the experimental work of Corcione. The coupled nonlinear equations were solved numerically using the finite difference method. Further, the heat transport rate is optimized using the response surface methodology (RSM). The significance of effective parameters on the flow structure, thermal pattern, concentration field, heat and mass transport rate are visualized through two-dimensional (2D) and three-dimensional (3D) surface plots. It is noticed that the chaotic motion of nanoparticles advances the thickness of the thermal and solutal boundaries. The velocity field has an inverse association with the applied magnetic field and its angle of inclination. The consequence of the Reynolds number is favorable for the velocity and temperature fields. The heat transport is more dominated by the Reynolds number compared to the chaotic motion of nanoparticles and thermophoretic aspect. Furthermore, the sensitivity of the Nusselt number to the Reynolds number, chaotic motion of nanoparticles and thermophoretic aspect are always negative.

Optimizing design of a free piston Stirling engine using response surface methodology and grey relation analysis

The performance analysis and optimization of a γ-type free-piston Stirling engine (FPSE) are conducted using Response Surface Methodology (RSM) and Grey Relation Analysis (GRA). The input-output parameters table is determined by the RSM. A regression model is presented to investigate the influence of structural parameters of FPSE on its performance. The relation coefficients for the four output parameters obtained from the RSM are determined to be 0.9980, 0.9983, 0.9999, and 0.9995, respectively, thus unequivocally demonstrating the exceptional precision of the RSM model. Also, the relationship between displacer and piston amplitudes, operating frequency, and output power and these parameters of Stirling engine is presented via 3D surface plots. The performance of the FPSE is optimized using the desirability approach and GRA, respectively, followed by a comparison of four groups of optimization results to determine the most suitable model. The maximum output power achieved is 78.02 W, with corresponding operating frequency, displacer amplitude, and piston amplitude values of 60.24 Hz, 2.55 mm, and 7.27 mm. Finally, by comparing pre- and post-optimization, the output power is increased by 36.85%. The GRA exhibits superior optimization compared to the RSM, thus providing valuable guidance for enhancing the optimization of FPSE in this study.

Combating Cariogenic Streptococcus mutans Biofilm Formation and Disruption with Coumaric Acid on Dentin Surface.

Streptococcus mutans, the primary cause of dental caries, relies on its ability to create and sustain a biofilm (dental plaque) for survival and pathogenicity in the oral cavity. This study was focused on the antimicrobial biofilm formation control and biofilm dispersal potential of Coumaric acid (CA) against Streptococcus mutans on the dentin surface. The biofilm was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) viability assay, microtiter plate assay, production of extracellular polymeric substances (EPSs), florescence microscopy (surface coverage and biomass μm2) and three-dimensional (3D) surface plots. It was observed that CA at 0.01 mg/mL reduced bacterial growth by 5.51%, whereases at 1 mg/mL, a significant (p < 0.05) reduction (98.37%) was observed. However, at 1 mg/mL of CA, a 95.48% biofilm formation reduction was achieved, while a 73.45% biofilm dispersal (after 24 h. treatment) was achieved against the preformed biofilm. The MTT assay showed that at 1 mg/mL of CA, the viability of bacteria in the biofilm was markedly (p < 0.05) reduced to 73.44%. Moreover, polysaccharide (EPS) was reduced to 24.80 μg/mL and protein (EPS) to 41.47 μg/mL. ImageJ software (version 1.54 g) was used to process florescence images, and it was observed that the biofilm mass was reduced to 213 (μm2); the surface coverage was reduced to 0.079%. Furthermore, the 3D surface plots showed that the untreated biofilm was highly dense, with more fibril-like projections. Additionally, molecular docking predicted a possible interaction pattern of CA (ligand) with the receptor Competence Stimulating Peptide (UA159sp, PDB ID: 2I2J). Our findings suggest that CA has antibacterial and biofilm control efficacy against S. mutans associated with dental plaque under tested conditions.

Optimization of ultrasound-assisted extraction using response surface methodology and quantification of polyphenol compounds in Avicennia officinalis L. from Vietnam

Response surface methodology was used to estimate the optimum extraction parameters, for which the total phenolic content and total flavonoid content of Avicennia officinalis L. extract were the highest. Based on the 3D surface plots and regression analysis of the independent variables, the optimal conditions for the ultrasound-assisted extraction were as follows: methanol content, 55.27%; liquid-to-solid ratio, 14:1 (mL/g, v/w); temperature, 48.8 °C, and time, 9.66 min. Optimal extraction conditions were applied to validate the quantification. The bioactive compounds from the Avicennia officinalis L. extract were identified through ultra-fast liquid chromatography coupled to diode array detector for the first time. These methods were applied to quantify phenolic acids and flavonoids from A. officinalis extracts collected at six different locations in Vietnam. The results showed that the concentrations of these compounds varied from 0.319 ± 0.022 to 3.524 ± 0.125 mg/g in the methanol extract. The result showed that cinnamic acid is the major compound in A. officinalis collected in Vietnam. In the present study, an optimized ultrasound-assisted extraction was first designed to improve the content of phenolic acids and flavonoid compounds from A. officinalis. Additionally, the bioactive compounds from the A. officinalis extract were identified through UFLC-DAD for the first time.

Modeling based on machine learning to investigate flue gas desulfurization performance by calcium silicate absorbent in a sand bed reactor

Flue gas desulfurization (FGD) is a critical process for reducing sulfur dioxide (SO2) emissions from industrial sources, particularly power plants. This research uses calcium silicate absorbent in combination with machine learning (ML) to predict SO2 concentration within an FGD process. The collected dataset encompasses four input parameters, specifically relative humidity, absorbent weight, temperature, and time, and incorporates one output parameter, which pertains to the concentration of SO2. Six ML models were developed to estimate the output parameters. Statistical metrics such as the coefficient of determination (R2) and mean squared error (MSE) were employed to identify the most suitable model and assess its fitting effectiveness. The random forest (RF) model emerged as the top-performing model, boasting an R2 of 0.9902 and an MSE of 0.0008. The model's predictions aligned closely with experimental results, confirming its high accuracy. The most suitable hyperparameter values for RF model were found to be 74 for n_estimators, 41 for max_depth, false for bootstrap, sqrt for max_features, 1 for min_samples_leaf, absolute_error for criterion, and 3 for min_samples_split. Three-dimensional surface plots were generated to explore the impact of input variables on SO2 concentration. Global sensitivity analysis (GSA) revealed absorbent weight and time significantly influence SO2 concentration. The integration of ML into FGD modeling offers a novel approach to optimizing the efficiency and effectiveness of this environmentally crucial process.

DESIGN AND OPTIMIZATION OF NANO ENCAPSULATED BIO COMPOUNDS OF ASPARAGUS RACEMOSUS: BOX BEHNKEN APPROACH

Objective: The current study’s objective is to develop and optimize nanoencapsulated bio compounds of Asparagus racemosus (BCAR) utilizing the ionic gelation process to target the kidney for antiurolithiatic activity. Methods: Nanoencapsulated BCAR was prepared employing the ionic gelation method. Box Behnken Design (BBD) 3-factor, 3-level is used to examine the effects of formulation parameters and to enhance the desired responses. Characterization studies include Fourier transform infrared (FTIR), X-ray diffraction (XRD), particle size, zeta potential, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) performed to study the quality of optimized nanoparticles. Results: Mathematical equations and response surface plots were used to relate the dependent and independent variables. Diagnostic charts were used to show the varied factor-level permutations. The percentages of entrapment efficiency (% EE) and drug release (% DR) used in evaluation studies of optimized bio compounds of BCAR nanoparticles (OBCARNPs) were determined to be 80.67% and 77.4%, respectively. The Fourier transform infrared (FTIR) results showed that chitosan, sodium tripolyphosphate (NaTPP), and BCAR were compatible. Due to chitosan and NaTPP gelation in the case of OBCBANPs, X-ray diffraction (XRD) analyses have acknowledged the crystallinity. The particle size and zeta potential of the optimized formulation, found to be 48.8 nm and 14.1 mV, respectively, indicate the nanoparticles are in the nanorange and possess extreme stability by preventing particle convergence. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) studies reveal that the optimized formulation nanoparticles are spherical in shape, homogeneous, and have little aggregation. The accelerated stability studies showed that the optimized formulation was stable at different temperatures and relative humidity. Conclusion: The stable, optimized formulation was prepared, evaluated, and characterized. BBD is employed to optimize the formulation by minimizing the number of experimental runs and enhancing the desired responses. The optimized formulation further needs to investigate the in vivo studies for antiurolithiatic activity by targeting the kidney.

OPTIMIZATION AND CHARACTERIZATION OF MICROSPHERES OF BERBERINE HYDROCHLORIDE USING BOX-BEHNKEN DESIGN

Objective: The current work sought to optimize Berberine hydrochloride (BBH)-loaded microspheres by examining the link between design parameters and experimental results. Methods: BBH-loaded microspheres were prepared by using the water-in-oil emulsion cross-linking process and optimized with a three-factor, three-level Box-Behnken design (BBD). Grafted gum polyvinyl alcohol (PVA) ratio (w/w) (A), Revolutions per minute (RPM) (B), and Span 20 (%) (C) were independent variables. The dependent variables were Percent Entrapment Efficiency (% EE) (R1), Percent Drug Loading (% DL) (R2), and Particle Size (µm) (R3). The generated polynomial equations and response surface plots were used to relate the dependent and independent variables. Microscopic examination, %EE, and % DL were determined to evaluate the optimized formulation. Fourier transforms infrared (FT-IR) spectroscopy studies and stability studies of optimized formulation were also carried out. Results: The optimized formulation (FMS6) had a polymer content of 2% w/v [Grafted gum (36.96): PVA (63.04)], a span 20 (0.78 %), and a prepared at the speed of 1225.92 rpm. The observed responses were close to the improved formulation's predicted values. The particle size, % EE, and % DL were found to be 1.10 µm, 82.79% and 16.48%, respectively. FT-IR spectroscopy study indicated that the drug was entrapped in microspheres. Conclusion: BBD provides a systematic approach to optimize the BBH microsphere preparation process. Additionally, the stability study results confirmed that FMS6 is not only the ideal formulation but also stable, ensuring its suitability for practical applications.

Exploring the effect of substituents on the supramolecular assemblies built by non-covalent interactions in three closely related 1,3,4-oxadiazole-2(3H)-thione derivatives: An evaluation of antimicrobial and anti-proliferative activities

Three closely related 1,3,4-oxadiazole-2(3H)-thione N-Mannich bases were synthesized and characterized by spectroscopic and single crystal X-ray diffraction methods. X-ray analysis reveals that the title molecules adopt l-shaped conformation, and a slight structural deviation around substituent groups is noted. The Hirshfeld surface and 2D fingerprint plots demonstrate the effect of substituents (piperidine, morpholine, and thiomorpholine) on the intermolecular interactions. The CLP-PIXEL energy analysis identified the most significant interactions in the molecular dimers (that characterize the crystal packing) with respect to the total intermolecular interaction energies. These dimers are held together by various non-covalent interactions including C–H⋅⋅⋅S/N/O/Cl/π interactions in addition to unconventional lone pair⋅⋅⋅π interactions. A molecule with thiomorpholine substituent is favoured by two σ-hole interactions (Cl⋅⋅⋅Cl halogen bond and S⋅⋅⋅N chalcogen bond) in the solid state. Furthermore, the molecular electrostatic potential (MEP) surfaces and deformation electron density help to describe the existence of σ-hole on the Cl and thione S atoms. Noncovalent interaction index (NCI) and quantum theory of atoms in molecules (QTAIM) methods are used to delineate the nature of observed noncovalent interactions in the molecular dimers. In vitro data of antibacterial and anti-proliferative activities indicate that compound with morpholine substituent showed a moderate antibacterial activity against all tested Gram-positive bacterial strains. However, molecules with piperidine and thiomorpholine showed notable effectiveness against the HepG-2 cell line. Molecular docking analysis was performed with two liver cancer targets, VEGFR2 and RET, in order to understand the interactions between the ligand and the active site residues of these targets.

Numerical and experimental investigations on AA6063 extrudates: effect of number of portholes on extrusion load and weld strength

In aluminium extrusion process, metal flow is greatly controlled by the die geometry and a variety of intricate profiles can be achieved by designing dies of different configurations. In porthole die extrusion, number of portholes used for a profile is often determined by the subjective knowledge of designers. Nevertheless, extrusion load and weld strength of profile produced are not only dependent on extrusion ratio, temperature of deformation but also on the number of portholes along with other die geometry variables. In the present investigation, systematic studies were carried out on three different dies with four ports, three and two ports around die center to extrude profiles of outer diameter 29.4 mm and thickness 2 mm. Numerical simulations were carried out for estimation of pressure, temperature, strain, and strain rate parameters in the weld chamber for all the dies, followed by press trials and profiles produced were subjected to wedge expansion test. The results from numerical simulations indicated that pressure generated inside weld chamber increases with number of portholes. The surface plots indicated highest pressure of about 280 MPa for four port hole and about 276 MPa for three ports die and pressure of about 160 MPa was estimated for two port hole die at the entry of weld chamber , which is 65 mm from profile end. Similarly, temperature at profile exit was 551 °C for four portholes die and 546 °C for three portholes die and 537 °C for two portholes die. Furthermore, press trials indicated peak extrusion loads of 5241 kN, 4406 kN and 3961 kN respectively for four, three and two portholes die. Thus, the peak extrusion load decreased by about 16% for three port and about 25% for two ports die in comparison with four port die. Also, the extruded profiles in wedge expansion test indicated mean compression load of 22.70 ± 0.14 kN in four porthole die, mean compression load 22.29 ± 0.26 kN for three port die and mean compression load of 17.841 ± 0.27 kN.

An investigation on surface integrity and microstructure behaviour of AISI 304 stainless steel machined by die sinking EDM

Machining of AISI 304 enables the customization of parts to meet specific mechanical and aesthetic requirements, ensuring optimal performance and durability in various applications. In this study, electrical discharge machining (EDM) is introduced to machine AISI 304 stainless steel. To accomplish the desired machining characteristics (MRR, SR), different EDM factors are chosen, such as discharge current, pulse on time, and pulse off time. The experiment is planned using central composite design in response surface methodology (RSM). The impact of EDM variables on metal removal rate (MRR) and surface roughness (SR) is examined through surface plot. Regression coefficient values for MRR and SR are 92.37% and 83.28%, respectively, indicating an empirical relation between the factors and responses. The lack of fit values for MRR and SR were 3.87 and 1.49, respectively, which were lower than the average values. Thus, the developed model was sufficient. It was observed that MRR and SR increases with increase in all parameters, but decreases at higher range of parameters. As current and pulse on time increase, the ionization temperature generated in the machining zone which removed more quantity of materials from the workpiece. Due to ionization temperature, more craters and voids formed which made surface irregular and hard, resulted increased SR. At lower level of discharge current and pulse on time, insufficient spark intensity is developed which made cracks and globules on the surface. The estimated error of actual and expected values for MRR and SR are 7.07% and 5.12% respectively. The desirability of optimization was calculated to be 0.9710, indicating that parameters are within acceptable conditions.

A NUMERICAL APPROACH OF FORCED CONVECTIVE MHD CASSON HYBRID NANOFLUID FLOWS EXPOSED TO JOULE HEATING AND VISCOUS DISSIPATION OVER DIVERGING CHANNEL

The present study deals with boundary layer flows of buoyancy-driven magnetohydrodynamic, chemical-radiative, and temperature-sensitive Casson hybrid nanofluid over diverging channel. Copper (Cu) and aluminum oxide (Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) nanoparticles are suspended upon ethylene glycol-based non-Newtonian Casson fluid. The proposed model is applicable in power transmission systems the design of nuclear reactors where a moving plate is used as a control rod, and the design of compression molding processes. The boundary layer governing equations undergo nonsimilar transformations followed by a quasilinearization technique and an implicit finite difference scheme. Varga's algorithm is applied on the obtained block tri-diagonal system of equations. The study pertinent to dimensionless parameters like Reynolds number, Eckert number, Casson parameter, and Richardson's number on velocity, temperature, drag coefficient, and heat transfer profiles. Also surface plots are plotted for varied values of Casson parameter and magnetic parameter on skin friction and heat transfer coefficients. It is to be noted that for enhanced values of Casson parameter &amp;beta;, the velocity profile is augmented, and the temperature profile is declined. It is observed that the temperature profile is enhanced at the center of the channel for enhanced values of viscous dissipation parameter Ec.