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1

Treatment of Municipal Wastewater Using Electrocoagulation Process

Abshishek H., Vijayakumar H., Mahesh Kumar C L, Shwetha Kotagi Girisha

Civil and Environmental Engineering Reports

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2023

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Vol. 33, no. 4

1--13

EN

Treatment of Municipal wastewater by Electrocoagulation (EC) process using punched aluminium and zinc electrodes was studied in a batch EC cell reactor. Response surface methodology (RSM) based on Central Composite Design (CCD) was utilized to optimize the operating parameters for the removal of % Total Suspended Solids (TSS) and % Chemical Oxygen Demand (COD) from Municipal Sewage. Effect of operating parameters such as Electrode Distance (x1), Electrolysis Time (x2) and Voltage (x3) has been optimized for the removal of TSS and COD. The prediction of removal percentage of TSS and COD in various Operational circumstances is done by using Quadratic model. The significance of each operating parameter was computed by Analysis of variance (ANOVA). To achieve the maximum removal of % TSS and % COD, the optimum conditions were Electrode distance(x1)-3 cm, Electrolysis Time (x2)-70.299 minute and Voltage (x3)-6.5V. It was observed that the performance of electrocoagulation process increased up to 61.45% for COD removal, and 73.73% for TSS removal using punched electrode compared to plane electrodes.

2

Surface Roughness Reduction in A Fused Filament Fabrication (FFF) Process using Central Composite Design Method

Kandananond Karin

Production Engineering Archives

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2022

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Vol. 28, Iss. 2

157--163

EN

The objective of this study is to optimize the fabrication factors of a consumer-grade fused filament fabrication (FFF) system. The input factors were nozzle temperature, bed temperature, printing speed, and layer thickness. The optimization aims to minimize average surface roughness (Ra) indicating the surface quality of benchmarks. In this study, Ra was measured at two positions, the bottom and top surface of benchmarks. For the fabrication, the material used was the Polylactic acid (PLA) filament. A response surface method (RSM), central composite design (CCD), was utilized to carry out the optimization. The analysis of variance (ANOVA) was calculated to explore the significant factors, interactions, quadratic effect, and lack of fit, while the regression analysis was performed to determine the prediction equation of Ra. The model adequacy checking was conducted to check whether the residual assumption still held. The total number of thirty benchmarks was fabricated and measured using a surface roughness tester. For the bottom surface, the analysis results indicated that there was the main effect from only one factor, printing speed. However, for the top surface, the ANOVA signified an interaction between the printing speed and layer thickness. The optimal setting of these factors was also recommended, while the empirical models of Ra at both surface positions were also presented. Finally, an extra benchmark was fabricated to validate the empirical model.

3

Optimization of Acetaminophen and Methylparaben Removal within Subsurface Batch Constructed Wetland Systems

Mutar Zahraa Hasan, Mohammed Ahmed A., Al-Baldawi Israa Abdulwahab

Journal of Ecological Engineering

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2022

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Vol. 23, nr 1

228--239

EN

The response surface methodology accompanied by Central Composite Design (CCD) was employed in this study to optimize the Alternanthera spp-based phytoremediation process for the individual removal of acetaminophen and methylparaben. Two operational variables, including concentration (A) (20, 60,100 mg/L) and sampling time (B) (7, 14, 21, and 35 days) were involved in the study for removal efficiency (Y) as response. CCD had required a total of 18 experiments for each compound. Analysis of variance (ANOVA) was conducted to verify the adequacy of the proposed mathematical models and revealed good agreement with the experimental data. The observed R2 values (0.9732 and 0.9870), adjusted R2 (0.9620 and 0.9816) and predicted R2 (0.9383 and 0.9721) for AC and MP, respectively, indicated that the developed models were significant at the 95% probability level. Concentration factor was found to be insignificant in the mathematical models; in contrast, sampling time was found to be of a crucial role. The removal of AC and MP were 89.23% and 64.48% under optimum conditions of A = 100 mg/L and B = 35 days respectively. The validation test confirmed the predicted results obtained by Central Composite Design, as the removals achieved under optimum conditions were 91.04% and 59.17% for AC and MP, respectively, which were in good agreement with the results proposed by the theoretical design.

4

Batch and Continuous Photo-Fenton Oxidation of Reactive-Red Dye from Wastewater

Hassan Ali A., AlJaberi Forat Yasir, Al-Khateeb Raid T.

Journal of Ecological Engineering

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2022

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Vol. 23, nr 1

14--23

EN

This paper aims to investigate the ability of photo-Fenton technology to remove Reactive Red dye (RR-dye) from wastewater using batch and continuous operating modes. The batch mode of photo-Fenton removal of organic content was conducted under the influence of solution pH (3–10), hydrogen peroxide (25–100 ppm), irradiation time (20–90 min), ferrous sulphate (5–20 ppm), and temperature (25–60 °C). For comparison, the continuous treatment was conducted under the influence of the flow rate of the contaminated solution (10, 20, 30, 40, and 50 mL/min). The results revealed that the treatability of the batch mode was more effective compared to the continuous mode. In the batch process, the organic contaminant was completely removed compared to that of 82% obtained when the continuous system was performed. The optimization process showed that the optimal values of the operating variables in the case of the batch removal of RR-dye were 3, 78 ppm, 90 min, 20 ppm, and 60 °C for pH, hydrogen peroxide, irradiation time, ferrous sulphate, and temperature, respectively. Moreover, the reversion F-value was 21.69, the probability P value was less than 0.001, and the correlation coefficient was (R2 = 0.9455), which illustrative the significance of the model obtained for the batch process.

5

Response Surface Methodology for Treatment of Paper Mill Wastewater by Using Inorganic Polymeric Coagulant

Ali Mohammed Eid M., Moniem Shimaa M. Abdel, Abdelsalam Hazem, Ammar Nabila S., Ibrahim Hanan S.

Ecological Engineering & Environmental Technology

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2022

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Vol. 23, iss. 5

153--163

EN

Inorganic polymeric ferric chloride (POFC) coagulant with proposed structure of Fen (Cl2.2OH0.8)n is synthesized using waste materials and characterized by XRD. In the current work scrutinized efficiency of POFC for paper mill wastewater (PMW) treatment using response surface methodology (RSM) with central Composite Design (CCD) modeling. Different factors; dose, rapid mixing speed, and rapid mixing time are used for optimize the coagulation process using POFC for treating PMW. The turbidity and chemical oxygen demand (COD) removals are the indicators for assessing POFC efficiency. The obtained result for XRD confirms the production of new material of inorganic polymeric coagulants. Based on RSM modelling, there is a high correlation between the experimental and predicated removals of turbidity and COD. Subsequently, the model is significantly applied for predicating COD and turbidity removals at different operation condition. Conclusively, the obtained results proposed for practical application of POFC coagulant for treatment of paper mill wastewater for COD and turbidity elimination. Furthermore, the applied RSM with CCD is talented model for optimizing treatment of PMW.

6

Optimization of Injection Moulding Process via Design of Experiment (DOE) Method based on Rice Husk (RH) Reinforced Low Density Polyethylene (LDPE) Composite Properties

Jaya Haliza, Zulkepli Nik Noriman, Omar Mohd Firdaus, Abd Rahim Shayfull Zamree, Nabiałek Marcin, Jeż Kinga, Al Bakri Abdullah Mohd Mustafa

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

719--727

EN

Optimal parameters setting of injection moulding (IM) machine critically effects productivity, quality, and cost production of end products in manufacturing industries. Previously, trial and error method were the most common method for the production engineers to meet the optimal process injection moulding parameter setting. Inappropriate injection moulding machine parameter settings can lead to poor production and quality of a product. Therefore, this study was purposefully carried out to overcome those uncertainty. This paper presents a statistical technique on the optimization of injection moulding process parameters through central composite design (CCD). In this study, an understanding of the injection moulding process and consequently its optimization is carried out by CCD based on three parameters (melt temperature, packing pressure, and cooling time) which influence the shrinkage and tensile strength of rice husk (RH) reinforced low density polyethylene (LDPE) composites. Statistical results and analysis are used to provide better interpretation of the experiment. The models are form from analysis of variance (ANOVA) method and the model passed the tests for normality and independence assumptions.

7

Using Design Space and Response Surface Methodology for developing a liquid chromatography method for simultaneous determination of five statins in pharmaceutical form

Belmir H., Abourriche A., Bennamara A., Saffaj T., Ihssane Bouchaib

Acta Chromatographica

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2021

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Vol. 33, no. 4

345--353

EN

This study describes the development of a method allowing the simultaneous separation and quantification of five statins by High performance liquid chromatography/Diode Array Detector (HPLC/ DAD). Optimization was accomplished using chemometric tools such as the Design Space (DS) and Response Surface Methodology (RSM). Central Composite Design (CCD) and DS were applied for the optimization of the chromatographic procedure as well as the robustness of the chromatographic method by taking the ratio of the percentage of acetonitrile (%ACN) Buffer solution, the pH and the mobile phase flow rate as critical parameters. Satisfactory results were obtained after the optimization phase with a percentage of mobile phase equal to 46.19%, a pH of 4.16 and the flow rate is 1.4 mL min1 by setting the resolution limits above 6, and the target retention time of 20 min. Using the DS and CCD approach, we have developed a robust and reliable procedure for the simultaneous and accurate separation and quantification of the five statins.

8

Adsorption of lead ions onto chemically activated carbon from waste tire char and optimization of the process using response surface methodology

Rutto Hilary, Seidigeng Tumisang, Malise Lucky

Archives of Environmental Protection

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2019

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Vol. 45, no. 4

92--103

EN

Tires play an important role in the automobile industry. However, their disposal when worn out has adverse effects on the environment. The main aim of this study was to prepare activated carbon from waste tire pyrolysis char by impregnating KOH onto pyrolytic char. Adsorption studies on lead onto chemically activated carbon were carried out using response surface methodology. The effect of process parameters such as temperature (°C), adsorbent dosage (g/100 ml), pH, contact time (minutes) and initial lead concentration (mg/l) on the adsorption capacity were investigated. It was found out that the adsorption capacity increased with an increase in adsorbent dosage, contact time, pH, and decreased with an increase in lead concentration and temperature. Optimization of the process variables was done using a numerical optimization method. Fourier Transform Infrared Spectra (FTIR) analysis, X-ray Diffraction (XRD), Thermogravimetric analysis (TGA) and scanning electron microscope were used to characterize the pyrolytic carbon char before and after activation. The numerical optimization analysis results showed that the maximum adsorption capacity of 93.176 mg/g was obtained at adsorbent dosage of 0.97 g/100 ml, pH 7, contact time of 115.27 min, initial metal concentration of 100 mg/and temperature of 25°C. FTIR and TGA analysis showed the presence of oxygen containing functional groups on the surface of the activated carbon produced and that the weight loss during the activation step was negligible.

9

Modelowanie sił w szlifowaniu obwodowym płaszczyzn według różnych planów badawczych

Habrat W., Żółkoś M., Świder J., Socha E.

Mechanik

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2018

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R. 91, nr 10

929--931

PL

W artykule przedstawiono modelowanie sił w procesie szlifowania obwodowego płaszczyzn ze stali 100Cr6 za pomocą ściernicy M3X60K5VE01-35, przeprowadzone z zastosowaniem centralnego planu kompozycyjnego ortogonalnego (CCF) i planu Boxa-Behnkena. Do planowania eksperymentu oraz analizy wyników wykorzystano program Design-Expert. Modele sił uzyskane w ramach wybranych planów porównano na podstawie współczynników determinacji oraz wartości odchylenia standardowego składnika resztowego.

EN

The paper presents forces modeling with the use of DoE models, such as (Box-Wilson) central composite design in face centered variant (CCF) and Box-Behnken design in a surface peripheral grinding process of 100Cr6 steel with M3X60K5VE01-35 grinding wheel. Experiment design and result analysis were done with the use of Design-Expert software. Force models, obtained with application of selected designs of experiment, were compared on the basis of the coefficient of determination, and values of residual standard deviation.

10

Application of the central composite design to optimization of petroleum hydrocarbons removal from oilfield water using advanced oxidation process

Farzadkia M., Ghorbanian M., Biglari H., Gholami M., Mehrizi E. A.

Archives of Environmental Protection

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2018

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Vol. 44, no. 4

22--30

EN

In the last few years, RSM method has been used widely to analyze, optimize and evaluate the interaction of independent factors for chemical, biochemical, and environmental processes. This study examined and evaluated the applicability of this method to manage Oilfield Produced Water to prevent marine environment due to the presence of hard degradable compounds by ozonation process. In this study simulated oil-water sample and a homogenizer reactor was used. The main reactor used in this study was impeinger equipped with sintered glass filter through which the treated oil-water was entered to reactor in the form of discontinuous flow. After ozonation and at the end of the reaction time (60 min), the concentration of oil hydrocarbons was determined by a gas chromatography device equipped with a flame ionization detector. The performance of the central composite design (CCD) approach was evaluated by the F-Value, P-Value, R2, lack of fit test and Adequate Precision parameters to determine the influence of effective factors, including ozonation time, pH, ozone dose, and TPH concentration on the TPH removal efficiency. The mean TPH efficiency obtained from the design of the 30-step experiment resulting from surface-response method was 49.903%, with a standard deviation of 12.47. This study showed the high power of model adopted from the central composite design to predict the hydrocarbons removal from oilfield water using advanced oxidation process, and it was proved that this model can be used alone to determine the design space nature.

11

Central composite design application in oil agglomeration of talc

Polowczyk I., Kozlecki T.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

1061--1078

EN

Talc has many applications in various branches of industry. This material is an inert one with a naturally hydrophobic surface. Talc agglomeration is within the wide interest of pharmaceutical industry. Oil agglomeration experiments of talc were carried out to find out and assess the significance of experimental factors. Central composite design (CCD) was used to estimate the importance and interrelation of the agglomeration process parameters. Four experimental factors have been evaluated, i.e. concentration of cationic surfactant and oil, agitation intensity as well as time of the process. The median size of agglomerates (D50) and the polydispersity span (PDI) were used as the process responses. Logarithmic transformations of the responses provide better description of the model, than untransformed responses, with the reduced cubic model for D50 and quadratic model for PDI. This was supported by the Box-Cox plots. It was shown that there were many statistically important factors, including the concentration of cationic surfactant and stirring rate for D50, concentration of oil and stirring rate for PDI, as well as various interactions, up to third order for D50. Optimal conditions for minimum values of reagent amounts as well as mixing time and intensity for the maximum size of agglomerates but of rather narrow size distribution were found.

12

Effect of sintering parameters using the central composite design method, electronic structure and physical properties of yttria-partially stabilized ZrO2 commercial ceramics

Mendes A. M., Costa M. C. B., Araújo V. D., Motta F. V., Paskocimas C. A., Acchar W., Longo E., Bomio M. R. D., Cavalcante L. S.

Materials Science Poland

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2017

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Vol. 35, No. 1

225--238

EN

In this work, the effect of sintering parameters on electronic structure and physical properties of yttria-partially stabilized ZrO2 (YPSZ) commercial ceramics has been studied using the central composite design (CCD) method. The CCD method allows using empirical modelling with better fitting, by considering the interaction between both factors. Different temperature ranges and sintering times for processing of YPSZ ceramics have been used in order to evaluate the grain growth, hardness and volumetric shrinkage by the CCD method. X-ray diffraction patterns and Rietveld refinement data indicate that non-sintered YPSZ ceramics exhibits two phases related to tetragonal and monoclinic structures, while the sintered YPSZ ceramics exhibits a single phase related to a tetragonal structure. Moreover, the monoclinic structure presents zirconium (Zr) atoms coordinated to seven oxygen (O) atoms, while in the tetragonal structure Zr atoms are coordinated to eight O atoms. Field emission scanning electron microscopy images were employed to monitor the sintering and growth process. In addition, the response surfaces obtained from calculations presented the effect of thermal and kinetic variables on the physical properties such as average grain size, volumetric shrinkage and hardness of YPSZ ceramics.

13

Emission characteristics of a novel low NOx burner fueled by hydrogen-rich mixtures with methane

Dutka M., Ditaranto M., Løvås T.

Journal of Power Technologies

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2015

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Vol. 95, nr 2

105--111

EN

The use of hydrogen-rich fuels may be challenging for burner designers due to unique properties of hydrogen compared to conventional fuels such as natural gas. Burner retrofit may be required to use hydrogen-enriched fuels in combustion systems that are designed for natural gas combustion. This study aimed to experimentally investigate NOx emissions from a novel low NOx burner fueled by methane-hydrogen mixtures. The burner was tested in a cylindrical combustion chamber at atmospheric pressure. Burner thermal load of 25 kW (LHV) and air-fuel equivalence ratio of 1.15 were maintained throughout the experimental campaign. The influence of burner design parameters on NOx emissions was tested for various fuel compositions using a statistically cognizant experimental design. The study revealed that shifting the burner head upstream can deliver NOx emission reduction. In contrast, supplying fuel to the burner through secondary fuel ports increases NOx emissions, particularly when the burner head is shifted upstream. The lowest predicted NOx emissions from the burner are below 9 ppmvd at 3% of O2 and 14 ppmvd at 3% of O2 for 5% and 30% mass fraction of hydrogen in the fuel, respectively.

14

Investigation of surface integrity in high-speed ball end milling of cantilever shaped thin plate of Inconel 718

Bhopale N N, Pawade R S

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

616--622

EN

The paper addresses the effects of cutting speed and feed on the work piece deflection and surface integrity during milling of cantilever shaped Inconel 718 plate under different cutter orientations. The experiments were conducted on a CNC vertical milling machine using 10 mm diameter TiAlN coated solid carbide ball end milling cutter. Surface integrity is assessed in terms of micro hardness beneath the machined surface. The micro-hardness profile shows different patterns at various cutting parameters. It is observed that at large cutting speed as well as feeds, thicker work piece with larger work piece inclination shows higher micro hardness as compared to the other machining conditions.

15

Computer-assisted optimization of liquid-liquid extraction for HPLC analysis of domperidone and pantoprazole in human plasma

Sivakumar T., Manavalan R., Valliappan K.

Acta Chromatographica

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2008

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Vol. 20, no. 4

549-562

EN

This paper deals with optimization of a liquid-liquid extraction procedure for simultaneous HPLC analysis of domperidone and pantoprazole in human plasma. Central composite design and Derringer’s desirability function were used to optimize the concentration of KOH and the volume of ethyl acetate as the main factors affecting the liquid-liquid extraction procedure. After extraction, the analytes were separated quantitatively on a C 18 column with 10 mM pH 7.0 phosphate buffer-methanol-acetonitrile 48.46:20:31.54 ( υ / υ ) as mobile phase at a flow rate of 1.20 mL min -1 and with UV detection at 285 nm. It was concluded that extraction recovery of both the analytes was affected by KOH concentration and that recovery of pantoprazole was affected by ethyl acetate (extraction solvent) volume. Extraction recovery under optimum extraction conditions was 93.52% for domperidone and 92.72% for pantoprazole. The optimized extraction method was validated. Linearity was established for six levels in the ranges 10–1000 ng mL -1 for pantoprazole and 15–1000 ng mL -1 for domperidone. The lower limit of quantitation (LLOQ) and detection (LOD) were estimated as 9.84 and 5.91 ng mL -1 , respectively, for pantoprazole and 14.56 and 8.79 ng mL -1 for domperidone. The optimized method was linear, specific, accurate, and precise; the high recovery (>92%) and low relative standard deviation (<2.5%) enable reliable quantification of these analytes in spiked human plasma.