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Development of a Terbium-Sensitized Fluorescence Method for Analysis of Silibinin
摘要： Silibinin is a natural flavonoid with potent anticancer properties, as shown in both in vitro and in vivo experiments. Various methods have been used for silibinin analysis. Terbium-sensitized fluorescence methods have been widely used for the determination of drugs in pharmaceutical preparations and biological samples in recent years. The present work is aimed at providing a simple analytical method for the quantitative determination of silibinin in aqueous solutions based on the formation of a fluorescent complex with terbium ion. Terbium concentration, pH, and volume of buffer, the important effective parameters for the determination of silibinin by the proposed method, were optimized using response surface methodology. The fluorescence intensity of silibinin was measured at 545 nm using λex = 334 nm. The developed method was applied for the determination of silibinin in plasma samples after protein precipitation with acetone. Under optimum conditions, the method provided a linear range between 0.10 and 0.50 mg/L, with a coefficient of determination (R2) of 0.997. The LOD and LOQ were 0.034 and 0.112 mg/L, respectively. These results indicate that the developed method is a simple, low-cost, and suitable analytical method for the quantification of silibinin in aqueous solution and plasma samples.
关键词： Response surface methodology,Plasma samples,Quantitative determination,Silibinin,Terbium-sensitized fluorescence
更新于2025-09-23 15:21:01
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Modelling and optimization of process parameters to obtain maximum tensile strength for laser butt welding of 316L austenitic stainless steel sheets
摘要： The attribute of high power density but low energy-input in Laser welding offers exciting solutions to the commonly encountered disadvantages with conventional joining techniques. In this paper, 316L Austenitic Stainless Steel metal sheets were butt welded using Nd:YAG Laser welding system. Owing to its low cost and specific properties such as excellent toughness, higher creep, stress to rupture at elevated temperatures, 316L A.S.S finds wide range of applications in the industrial arena especially in the automobile and marine sectors. Hence, it becomes imperative to examine its post weld properties after performing laser welding and find optimized values of the parameters. The prominent process parameters like Laser Power, Travel speed and Focal length were analysed and optimised. Design of experiment statistical tool was embraced for the systematic conduct of the tests. Response Surface Methodology (RSM) and analysis of variance (ANOVA) techniques were employed to identify the significant process parameters affecting the weld. An empherical relationship involving the parameters was developed to predict the ultimate tensile strength. The 3D response surface plot and contour plots were generated for this model to elucidate the interaction effect of Laser parameters (Travel speed and Focal length), (Laser Power and Focal Length) & (Laser Power and Travel Speed) on Ultimate Tensile Strength. The welded specimens cut by electric discharge machining were prepared for tensile testing as per the ASTM standard. The Universal Testing Machine was used to test the welded specimen. Microhardness Testing was also carried out on the base material and the Heat Affected Zone (HAZ) using Vickers Hardness Testing machine. The tensile tested specimens were used for metallurgical analysis using Scanning Electron Microscope (S.E.M.). Specimen prepared for metallurgical analysis were sectioned, mounted, ground and polished in accordance with recommended procedures in ASTM practice E 3-11. The metallurgical observations showed the existence of undulating topography of ductile fracture surfaces. The investigations reveals that the actual values of the Ultimate tensile strength of the weld were falling close with the predicted strength obtained through the proposed model. It can be concluded that the proposed model in this work can be utilised to predict tensile strength of the weld with more precision.
关键词： Design of Experiments,Ultimate tensile strength,316 L A.S.S,Response Surface Methodology (RSM),Nd:YAG Laser welding
更新于2025-09-23 15:19:57
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Advanced Coating Materials || Investigations on Laser Surface Modification of Commercially Pure Titanium Using Continuous-Wave Nd:YAG Laser
摘要： Laser transformation hardening, a type of laser heat treatment technique, has advantages over the traditional hardening techniques, which include high precision, automation control with the choices of optimum desired minimum hardened depth of 241 microns (0.241 mm) for low laser beam power: 750 Watts have been achieved in this research work. In the present study, the laser transformation hardening of commercially pure titanium sheet material of thickness being 1.6 mm is investigated using CW (continuous-wave) 1.6-kW solid-state Nd:YAG laser. Commercially pure titanium has widespread application in various fields of industries including the medical, nuclear, automobile, and aerospace. A full factorial design (FFD) with Response Surface Methodology (RSM) is employed to establish, optimize, and investigate the relationships of three laser transformation hardening process parameters such as laser power, scanning speed, and focused position on laser hardened bead profile parameters such as hardened bead width, hardened depth, angle of entry of hardened bead profile, heat input, and power density. RSM is used to develop pseudo-closed-form models from the computational parametric studies. Effects of laser process parameters: laser power, scanning speed, and focal point position on laser hardened bead geometries such as hardened bead width, hardened depth, an angle of entry of hardened bead profile, heat input, and power density were carried out using RSM. Results indicate that the scanning speed and laser power have the significant effect as compared to the focal point position on the laser hardening process parameters. The scanning speed has a positive effect on all responses while the laser power has a positive effect particularly on hardened bead width and angle of entry of hardened bead profile as compared to hardened depth and heat input. The optimum laser hardening conditions are identified sequentially to minimize hardened depth, an angle of entry of hardened profile, heat input, power density, and maximum hardened bead width. The validation results demonstrate that the developed models are accurate with low percentages of errors observed.
关键词： bead geometry,full factorial design,response surface methodology,analysis of variance,Laser transformation hardening
更新于2025-09-19 17:15:36
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Control and prediction of forming quality in curved surface multi-track laser cladding with curve paths
摘要： This research investigated the influence of different processing parameters in curved surface multi-track laser cladding with curve paths. Mathematical models of flatness ratio, incomplete fusion, and pore area in the clad were developed by central composite design with altering the input laser power, scanning speed, gas flow, and overlapping rate. Response surface methodology was used to analyze the correlation of different processing parameters affecting the selected responses. A clad with better flatness ratio was achieved by properly increasing the laser power and gas flow while reducing the overlapping rate. Appropriately increasing the laser power and overlapping rate while reducing the scanning speed and gas flow effectively diminished the incomplete fusion. Less pore area in the clad was obtained by appropriately increasing the laser power and overlapping rate while reducing the scanning speed and gas flow. Afterwards, desired processing parameters set was obtained by the optimization with the target of maximizing the flatness ratio and also minimizing the incomplete fusion and pore area. Experimental validation with this processing parameter setup provided satisfactory clad, and the error rate for the flatness ratio, incomplete fusion, and pore area was 1.708%, 5.714%, and 6.522%, respectively. This paper provides the theoretical guidance for the prediction and control of the flatness ratio, incomplete fusion, and pore area in curved surface multi-track laser cladding with curve paths.
关键词： Central composite design,Response surface methodology,Curved surface,Laser cladding
更新于2025-09-19 17:13:59
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Optimization of process parameters in laser transmission welding for food packaging applications
摘要： Plastics' joining is used widely in food processing applications for the packaging of increasingly diverse food products. Laser transmission welding is an attractive proposition for such applications as it can significantly reduce tooling costs and potential downtime at product changeovers. In order to fulfil this promise in an industrial environment, an effective means of process parameter prediction is required. In this paper, goal driven optimization is conducted, utilizing numerical simulations as the basis for the prediction of optimal process parameters for the laser transmission welding of polyethylene film to a polypropylene substrate. A key consideration of the optimization process is the requirement for specific, pre-defined bonded track widths.
关键词： MOGA,Laser,Finite Element,Optimization,Response Surface
更新于2025-09-19 17:13:59
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Fabrication of bi-layer PMMA and aluminum 6061-T6 laminates by laser transmission welding: Performance prediction and optimization
摘要： Laser transmission welding can be effectively used in fabrication of laminated parts. In the present work an attempt was made to fabricate a polymeric laminate structure made of polymathic methacrylate (PMMA) and aluminum 6061-T6 by laser transmission welding process. A series of laser welding experiment has been carried out to analyze effect of laser power, welding speed, focal position and axial pressure on lap shear force and weld seam width. Response surface methodology including regression analysis, analysis of variances and desirability approach function has been utilized here to analyze the processing data. It is found from the results that focal position has greatest influence on both the lap shear force and weld bead width. Optimization is also carried out in two different criteria for achieving desired welding performance. The optimization results obtained by this approach are consistent well with the results measured through confirmatory experiments.
关键词： response surface methodology,polymer-metal lap joint,optimization,laser transmission welding
更新于2025-09-19 17:13:59
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Optimization and performance analysis of a solar concentrated photovoltaic-thermoelectric (CPV-TE) hybrid system
摘要： This work presents, for the first time, a statistical model to forecast the electrical efficiency of concentrated photovoltaic-thermoelectric system (CPV-TE). The main objective of this work is to analyze the impact of the input factors (product of solar radiation and optical concentration, external load resistance, leg height of TE and ambient temperature) most affecting the electrical efficiency of CPV-TE system. An innovative and integrated approach based on a multi-physics numerical model coupling radiative, conductive and convective heat transfers Seebeck and photoelectrical conversion physical phenomena inside the CPV-TE collector and a response surface methodology (RSM) model was developed. COMSOL 5.4 Multiphysics software is used to perform the three-dimensional numerical study based on finite element method. Furthermore, results from the numerical model is then analysed using the statistical tool, response surface methodology. The analysis of variance (ANOVA) is conducted to develop the quadratic regression model and examine the statistical significance of each input factor. The results reveal that the obtained determination coefficient for electrical efficiency is 0.9945. An excellent fitting is achieved between forecast values obtained from the statistical model and the numerical data provided by the three-dimensional numerical model. The influence of the parameters in order of importance on the electrical efficiency are respectively: product of solar radiation and optical concentration, the height legs of TE, external electrical resistance load, and ambient temperature. A simple polynomial statistical model is created in this work to predict and maximize the electrical efficiency from the solar CPV-TE system based on the four investigated input parameters. The maximum electrical efficiency of the proposed CPVTE (17.448%) is obtained for optimum operating parameters at 229.698 W/m2 value of product of solar radiation and optical concentration, 303.353 K value of ambient temperature, 2.681Ω value of resistance electrical load and at 3.083 mm value of height of TE module.
关键词： Concentrated photovoltaic-thermoelectric system (CPV-TE),Electrical efficiency enhancement,Response surface methodology (RSM)
更新于2025-09-19 17:13:59
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Numerical Simulation and Parameters Optimization of Laser Brazing of Galvanized Steel
摘要： In order to study the heat phenomenon of laser brazing galvanized steel, the experiments of laser brazing were carried out, in which the base metal is galvanized steel sheets and CuSi3 is used as filler metal. The numerical simulation of temperature field was carried on by the finite element method, and the simulation result was validated through comparative experiment. The composite heat source model of gauss double ellipsoid was used. Temperature field of different process parameters have been calculated. The results show that: The peak temperature and temperature gradient on the joint are lower when the laser power is 1 600 W, the brazing speed is 0.96 m/min. Response surface methodology was applied to the simulation data, and mathematical models was built based on Box-Behnken Design using linear and quadratic polynomial equations. The results indicate that the proposed models predict the responses adequately within the limits of brazing parameters being used. The optimum brazing parameters were found, and it is more favorable to form the brazed joint of good quality at the laser power of 1 600 W, brazing speed of 0.96 m/min, filler wire speed of 1.19 m/min, defocusing distance of 30 mm.
关键词： numerical simulation,laser brazing,response surface methodology,optimization
更新于2025-09-19 17:13:59
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New engineered and environmentally friendly dye‐sensitized solar cells: Efficient extraction of dyes from Cytisus, <i>Alcea rosea</i> , and Roselle
摘要： In this study, an efficient extraction of natural dyes from three plants such as Cytisus, Alcea rosea, and Roselle was carried out by solid‐liquid extraction method. Extraction conditions were optimized using the Response Surface Methodology (RSM). Temperature, time, and solvent ratio of extractions were the variables, and absorption intensities in maximum wavelength of extracted samples were the response of experiments. Optimum extraction conditions for the Cytisus, A rosea, and Roselle flowers were at 55°C in 60 minutes, 44°C in 40 minutes, and 54°C in 32 minutes, respectively. Also, the best solvent for extraction of dyes was pure ethanol and pure water, respectively, for the Cytisus, A rosea, and Rosell. Moreover, results of the study showed that absorption intensities of the Cytisus, A rosea, and Roselle were equal to 1.182 at 400 nm, 1.532 at 540 nm, and 1.932 at 520 nm, respectively. To fabricate solar cells, anode electrode was coated by a thin layer of TiO2. The surface morphology of TiO2 film investigated by SEM and AFM showed a suitable homogeneity of TiO2 film without crack with an average particle size of 25 to 30 nm. Atomic force microscopy (AFM) images demonstrated that the average roughness of TiO2 thin film is about 205 nm, while the surface roughnesses of anodes was equal to 154, 101, and 119 nm after applying the Cytisus, Roselle, and A rosea on TiO2 film, respectively. Fabricated solar cells were characterized by photovoltaic and IPCE tests. Results represented that fabricated solar cells synthesized by extracted dye from Roselle had the best performance compared with other cells. The efficiency of this cell was equal to 0.842%, with an open‐circuit voltage (Voc) of 0.644, a short‐circuit current (Jsc) of 1.912, a fill factor (FF) of 0.683, and an incident photon‐to‐current efficiency (IPCE) of 18.943%.
关键词： Alcea Rosea,dye‐sensitized solar cell,Response Surface Methodology,dye extraction,Cytisus,Roselle
更新于2025-09-19 17:13:59
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Predictive Modeling Of Laser Assisted Hybrid Machining Parameters Of Inconel 718 Alloy Using Statistical And Artificial Neural Network
摘要： Laser assisted hybrid machining being researched in past decade on various difficult to machine materials to improve the machinability. Predictive modeling approaches such as response surface method (RSM) and artificial neural network (ANN) are widely applied for model development. However, no reported work using RSM and ANN approaches to predict the relationship between the experimental variables (speed, feed, laser power and beam apporach angle) on surface roughness Ra (μm). Furthermore, coefficient of correlation (R2), root mean square error (RMSE) and model predictive error (MPE) are considered as a performance measures for their effectiveness. The results show that the ANN model estimates the machinability indices with high accuracy with a limited number of experiments compared to the response surface model. From the comparative study, ANN model is found to be capable for better prediction of response than the RSM model. ANN model provides a maximum precision benefit of 10% for surface roughness Ra (μm) compared with RSM model. Also the calculated Pearson correlation coefficient showed a robust relationship between the laser beam angle and Ra, surface roughness followed by the speed.
关键词： response surface methodology,surface roughness,neural network,empirical models
更新于2025-09-16 10:30:52