Factorial Experimental Design Methodology Research Articles

Influence of drying variables on the properties of noni powder obtained by spouted bed

The influence of variables on the spouted bed drying process was analyzed to obtain the noni Pulp powder and compare it with the powder obtained by freeze-drying. The full factorial experimental design methodology of 2² + 3 central points was used, with the independent variables: drying temperature (50, 60, and 70 °C) and concentration of the carrier agent (15, 20, and 25%) with an airspeed of 8 m/s. The drying conditions positively affected the activity of water, acidity, ash, and soluble solids, presenting an increase in the values of the dried powders. Ascorbic acid, on the other hand, had a decrease in its concentration. The range of the antioxidant activity (DPPH), antioxidant activity (ABTS), and total phenolic compounds (TPC) of fresh, freeze-dried, and dried fruits were 5.23 − 17.87 mg TE/g extract, 8.91 − 11.08 mg TE/g extract, and 1159.2–3208.3 mg GAE/100g sample, respectively.

Cylinder accuracy analysis of tangential turning of disk-like workpieces with increased cutting speed

Tangential turning, a precision high-speed finishing procedure, is crucial for achieving superior surface quality and dimensional accuracy in cylindrical workpieces. This advanced machining technique leverages tangentially applied cutting forces to minimize tool deflection and vibration, thereby enhancing the surface integrity of the final product. Despite its advantages, tangential turning poses challenges in maintaining cylindrical accuracy, necessitating a thorough investigation of cylindrical error. Cylindrical error, the deviation of the machined surface from a perfect cylinder, significantly impacts the functional performance of precision components. Factors such as tool wear, machine dynamics, and thermal effects can induce these errors, demanding comprehensive studies to optimize process parameters and tool paths. By thoroughly analyzing cylindrical error, manufacturers can refine tangential turning processes, ensuring high precision and consistency in high-speed finishing operations. This research underscores the importance of precision error analysis in advancing manufacturing capabilities and achieving stringent quality standards. Cylindrical accuracy is analyzed using the full factorial experimental design methodology to carry out practical cutting experiments, where the cutting speed, feed, and depth of cut were the altered variables. The cylindricity error, peak maximum departure, their ratio, and coaxiality are measured and analyzed. The main effect analysis and detailed study are elaborated using the determined equation. It is found that decreasing the studied parameters is advisable if increasing cylinder accuracy is needed.

Comparative study of one‐pot and facile methods to synthesize codoped CQDs with low band gap and photovoltaic properties

AbstractThree different one‐pot methods of electrochemical, solvothermal, and pyrolysis were applied for the synthesis of nitrogen‐doped carbon quantum dots (N‐CQDs), N‐F codoped carbon quantum dots (CQDs), and N‐S codoped CQDs from monoethanolamine and citric acid precursors. Ammonium fluoride and/or thiourea were used as the precursors of the second dopant corporation. The effective synthesis parameters were studied on the basis of the factorial experimental design methodology to maximize absorption edge and reduce band gap in UV‐visible spectroscopy. Among the best results, the synthesized N‐F/CQDs prepared from ammonium fluoride and citric acid in monoethanolamine revealed the highest absorption edge of 650 nm, the band gap of 1.91 eV, and the particle size of 24 ± 7 nm using the pyrolysis method. The X‐ray photoelectron spectroscopy (XPS) analysis indicated simultaneous doping of F and N atoms in the CQDs structure, and the photoluminescence (PL) analysis revealed excitation‐dependent properties, which are effective for optical sensor and solar cell applications.

Optimisation of mechanical properties of polyethylene terephthalate fibre/fly ash hybrid concrete composite

The study focuses on the prediction and optimisation using modelling with respect to the fresh and hardened properties of polyethylene terephthalate (PET) fibre reinforced concrete containing partial cement replacement with fly ash. Full factorial experimental design methodology was employed to fabricate the test specimens by simultaneously varying the independent factors to develop a model for overall response variation. Numerical optimisation was carried out concerning the fibre reinforced concrete's fresh and hardened mechanical properties. Predictive modified quadratic equations were developed for slump value, compressive, flexural, split tensile strength and total cost. Analysis of variance test was carried out for all the responses indicated and the developed model could predict the slump value and mechanical properties of the fibre reinforced concrete correctly and effectively with a coefficient of determination in the range of 0.5–0.9467. The optimum constituent combination for maximum mechanical strength at the lowest possible cost was found to be 15.76 % fly ash and 0.32 % PET fibre. These optimum values corresponded to responses of 25.65 MPa, 3.69 MPa, 2.36 MPa, 31.48 mm, R2744.17 for compressive strength, flexural strength, tensile strength, slump value and total cost, respectively. These predictions were validated experimentally, and a good correlation was observed between the actual and predicted values based on the observed standard deviations of 0.1335, 0.031, 0.005, 0.676, 0.02 for compressive strength, flexural strength, tensile strength, slump value and cost, respectively. Concrete slabs were optimised for various possible end uses, and the optimum PET fibre % and fly ash % were ascertained. The optimum combination for suspended slabs was 19.09 % for fly ash and 0.34 % PET fibre. These values corresponded to responses of R2742.03/kg/m3, 2.30 MPa, 3.68 MPa, 24.77 MPa, 30.60 mm for the total cost, split tensile, flexural, compressive strength and slump value. For foundation slabs, the optimum combination was 3.94 % fly ash and 0.65 % PET fibre, and the corresponding response values are R 2760.47 /kg/m3, 1.82 MPa, 3.26 MPa, 19.32 MPa and 10.78 mm for a total cost, split tensile, flexural, compressive strength and slump value, respectively. For paving slabs, the optimum combination was 0.65 % PET fibre giving a response of R 2775.13 kg/m3, 1.41 MPa, 3.29 MPa, 19.11 MPa and 9.92 mm for total cost, split tensile, flexural, compressive strength and slump value, respectively.

Bio-fiber reinforced roller compacted concrete designed for road construction: feasibility of date palm fibers in pavements

The current study is an attempt to test the feasibility of bio-fibers for roller compacted concrete (RCC). Date palm fibers (DPF) were utilized as a filler to make a different type of RCC designed for road construction. An experimental investigation has been carried out to determine the effect of these fibers on two types of mixtures: (i) without air-entraining agent (AEA) (ii) containing AEA. The experiments were conducted with mixtures prepared, natural, and 0.1% DPF reinforced RCC. 12 mixtures were prepared with four levels of AEA (0%, 0.01%, 0.05%, and 0.1%) and two levels of compaction energy (CE) (2400 kJ/m3 and 4800 kJ/m3). They were tested for compressive strength, abrasion resistance (Cantabro test), and ultrasonic pulse velocity. Concerning durability, freeze–thaw resistance was investigated. The results showed that the inclusion of date palm fibers had an important effect, as, it not only improved the physical and mechanical characteristics, but also found to ameliorate the durability of RCC mixes significantly. Relationships between such factors test are completed using the factorial experimental design methodology to develop mathematical models for predicting RCC properties. The obtained results are promising for further reflection on a large scale to explore the issue of strengthening RCCs with bio-fibers.

Experimental Design Analysis of Murexide Dye Removal by Carbon Produced from Waste Biomass Material

The aim of this work is to investigate the adsorption of an anionic dye, the Murexide (MX) present in aqueous solution, on activated carbon, derived from prickly pear seed cake biomass after bio-oil extraction. The obtained adsorbent used was characterized by Bohem titration, pH of point of zero charge (pHPZC), FTIR spectroscopy, Brunauer–Emmett–Teller surface area (SBET), and scanning electron microscopy (SEM). The different experimental parameters of the adsorption process, such as temperature, contact time, initial dye concentration, and adsorbent dose, were studied. For the optimization of the process, the effects of these parameters were investigated using the full factorial experimental design methodology. Design Expert 11.1.2.0 Trial software was used for generating the statistical experimental design and analysing the observed data. Langmuir and Freundlich’s adsorption models were employed to provide a description of the equilibrium isotherm. The adsorption process was found to obey Langmuir, which indicates that the Murexide had formed a monolayer onto activated carbon. Furthermore, according to the regression coefficients, it was observed that the kinetic adsorption data can fit better by the pseudo-second-order model compared to the first-order Lagergren’s model. The thermodynamic studies indicated that the adsorption of Murexide occurs in a spontaneous and exothermic process. The regeneration process of the exhausted adsorbent was studied to assess the economic and operational feasibility. According to the obtained findings, it is proposed that the activated carbon prepared from prickly pear seed cake retains a high potential for Murexide removal and is suitable for repetitive usage.

Recovery of mangrove sediment contaminated with fuel oil by endogenous microbial consortium

This work aimed to select a microbial consortium enriched with isolated microorganisms of mangrove sediment as to its capacity to recover sediment contaminated by lubricating oil. The promising microorganisms were selected using the colorimetric dichlorophenol indophenol technique (DCPIP) using lubricating oil as the carbon source, to evaluate the emulsifying and enzymatic activity of the microorganisms. The antagonism test was also used for further evaluation of the consortia. The fractional factorial experimental design methodology (2n) was used to establish the process conditions for the subsequent accomplishment of the degradation kinetics of the lubricating oil by the selected microorganisms and consortium. Eight bacteria and three fungi were evaluated, of which five were selected with a 36 h turn of the DCPIP indicator. Eleven microorganisms produce emulsifying substances and five produce enzymes. The results showed that the best consortium was B5F2F4, with a degradation rate of 95% of the phenol at 70 rpm in 250 μL of the oil. The kinetics of oil degradation showed a phenol degradation rate of 65% after 24 days of treatment. The microorganisms are suitable for the degradation of phenol, the main constituent of the oil, and can be used as a recovery model for environments contaminated with hydrocarbons.

Electrodegradation of tetracycline using stainless steel net electrodes: Screening of main effective parameters and interactions by means of a two-level factorial design

Performance of electrodegradation process using stainless steel net electrodes was explored for removal of tetracycline (TC) from synthetic wastewater in a laboratory batch study. Main effects of various operating parameters, such as initial TC concentration (20 and 100 mg/L), reaction pH (3.0 and 9.0), current density (4.1 and 17.1 mA/cm2), agitation speed (250 and 750 rpm), and electrolysis time (20, 50, and 80 min), and their interactions on the TC removal efficiency, were optimized by means of a five-factor and two-level factorial experimental design methodology. The significance of responses obtained from the proposed design (sixteen experimental runs under batch mode conditions) was statistically evaluated by preparing a Pareto chart, half-normal probability plot, and plots of main effects and their interactions (herein referred to as Factions) within the framework of the analysis of variance (ANOVA). The statistical results corroborated with 95% certainty that TC concentration, pH, and current density showed the largest effects (absolute values) on the TC removal efficiency. Besides the most effective Factions, a sodium sulfate (used as supporting electrolyte) dose of 1 g/200 cc was determined as the optimum value for the studied process. Under the conditions of an initial TC concentration=20 mg/L, a reaction pH=3.0, current density=17.1 mA/cm2, an agitation speed=250 rpm, and an electrolysis time=20 min, about 70% of TC could be successfully removed from the simulated wastewater. Findings of this experimental study clearly confirmed the applicability of the electrodegradation process for the removal of a broad spectrum antibacterial agent like TC, and also demonstrated the effectiveness of the factorial design methodology before transferring the obtained experimental knowledge for a full-scale facility.

Application of factorial experimental design methodology for the removal of phenol from water by innovate hybrid bioprocess

The purpose of this work was to study the phenol elimination by immobilized bacteria cells on a combined material. The immobilization by inclusion of Pseudomonas aeruginosa in calcium alginate beads with powdered activated carbon (PAC) allows the adsorption and biodegradation of phenol simultaneously. The full factorial design methodology was carried out to estimate the influence of the considered parameters (initial phenol concentration, amount of PAC, and diameter of beads) on the time of phenol removal. The adsorbent amount was the most significant parameter followed by the initial phenol concentration, while the effect of beads diameter was insignificant. The minimum time of phenol elimination obtained from the optimization procedure was 22.6 h. This optimum was achieved at 5 g/L of PAC and an initial phenol concentration of 100 mg/L.

The impact of ferrous iron/heat-activated persulfate treatment on waste sewage sludge constituents and sorbed antimicrobial micropollutants

Abstract The fate of the antimicrobial micropollutants oxytetracycline (OTC), ciprofloxacin (CIP), and triclosan (TCS) as well as that of the different constituents of sludge during treatment with ferrous iron and heat activated persulfate (Fe2+/heat/S2O82−) was investigated with full factorial experimental design methodology. Owing to a sulfate radical mechanism, considerable degradation of the micropollutants was achieved in the sludge. Iron promoted the degradation of the zwitterionic OTC and CIP antibiotics, recovered the phosphorus in the solid phase of the sludge, and enhanced the solubilization of the metal. The average degradation rates of OTC, CIP, and TCS were 95%, 84%, and >99%, respectively, whereas the overall rate of solubilization of the metal and the rate of precipitation of phosphate were 53% and 74%, respectively with S2O82− = 22.7 mM and Fe2+/S2O82− = 0.5 at 75 °C in 120 min.

Application of high‐temperature Fenton oxidation for the treatment of sulfonation plant wastewater

AbstractBACKGROUNDThis work explores the application of an intensified Fenton process to a sulfonation plant wastewater for its further discharge into an activated sludge plant. The application of high‐temperature Fenton to this kind of wastewater has not been reported so far. Herein, it has been demonstrated to provide a better performance than other advanced oxidation processes (AOPs).RESULTSThe factorial experimental design methodology applied for describing the effect of the operating conditions, temperature, hydrogen peroxide dose and pH, demonstrated that quadratic models satisfactorily fitted the experimental results according to the analysis of variance (ANOVA). Response surface, contour plots and surface projections of the models were obtained describing the individual and crossed effects of the operating conditions on the selected responses: linear alkylbenzene sulfonate (LAS), total organic carbon (TOC) and chemical oxygen demand (COD) reduction.CONCLUSIONSWorking at 94 °C, 70% of the stoichiometric H2O2 dose relative to initial COD, 1 h reaction time and the pH of the wastewater as received (1.7) enabled achievement of the discharge limits into the exiting activated sludge plant of the petrochemical complex where the sulfonation plant is located. © 2014 Society of Chemical Industry

Physicochemical and microtextural characterization of activated carbons produced from water steam activation of three bamboo species

The bamboo species Guadua angustifolia, Bambusa vulgaris striata and Bambusa oldhamii, were used as raw materials to obtain sixteen activated carbons. The physicochemical characterization showed wide adsorption capacity values (measured as iodine number) ranging from 280 to 1500mg/g, activation yields from 80 to 85%, average point of zero charge ≈9.9 and high content of quinonic surface groups. The influence of the bamboo species, particle size, time and temperature on the final surface properties was analysed using factorial experimental design methodology. Results indicated that the maximum adsorption capacity was achieved with B. vulgaris striata and 4h of activation time. The content of superficial oxygenated acidic groups on the samples were identified as the result of the third order interaction (raw material, time and temperature) allowing the control of the surface polarity on the final activated carbons. The scanning electron microscopy micrographs showed the shape conservation of the raw material after carbonization and activation stages. Transmission electron microscopy examinations suggest that structure of the prepared material is formed by highly disordered graphene-like layers as it was confirmed with the diffuse diffraction rings observed by selected area diffraction pattern and the shape of the carbon-K energy-loss near edge structure.

Application of 2III 7−3 fractional factorial experimental design to enhance enzymatic activities of Pleurotus ostreatus with high concentrations of polychlorinated biphenyls

A 2III 7−3 fractional factorial experimental design was used to establish 16 culture media, with and without PCBs to enhance the activities of laccase (Lac), manganese peroxidase (MnP), and versatile peroxidase (VP) produced by the white rot fungus Pleurotus ostreatus. The culture was added to 10,000 mg L−1 of transformer oil, containing 71% of the identified Arochlor 1242. The culture conditions were established with eight variables at two values (levels); pH (4 and 6), agitation (100 and 200 rpm), CuSO4 (150 and 250 mg L−1), MnSO4 (50 and 200 mg L−1), Tween 80 (13 and 3500 mg L−1), wheat straw (0 and 2.5 g L−1), sugarcane bagasse (0 and 2.5 g L−1),and Arochlor 1242 (0 and 7100 mg L−1) at 4, 8, 12, 16 and 20 days old culture. Laccase activity was enhanced at a high value of pH and low value of agitation (P<0.001) and correlated positively (R2= 0.9; α=0.05) with the removal of polychlorinated biphenyls (PCBs). VP activity was enhanced 27-fold with PCBs, Tween 80 and pH. The MnP activity was increased 1.2-fold with PCBs. The fractional factorial experimental design methodology allowed us to determine the P. ostreatus culture media conditions to enhance Lac and VP activities for efficient removal of Arochlor 1242 (one of the most recalcitrant organochloride pollutants). The factors that shown the greatest effect on Lac activity were: pH, agitation and high concentrations of Arochlor 1242.

Wet oxidation of benzoic acid catalyzed by cupric ions: Key parameters affecting induction period and conversion

The catalytic wet oxidation (CWO) of aqueous solutions of benzoic acid (BA) has been thoroughly investigated using various copper- and iron-containing catalysts with emphasis on cupric nitrate. The influence of BA concentration ranging from 50 to 150mg/L, catalyst loading varying between 50 and 150mg/L (i.e. 14 and 40mgCu/L), reaction temperature in the range 150–180°C and oxygen partial pressure in the range 10–30bar on the induction period of the reaction and BA conversion has been extensively studied. A factorial experimental design methodology has been implemented to assess the significance of the aforementioned parameters and a mathematical model has been proposed. The induction period observed during the CWO of BA is strongly affected by the reaction temperature and to a lesser extent by the initial BA concentration, the oxygen partial pressure, as well as by the second order interaction between initial BA concentration and oxygen partial pressure. Differences in chemical structure account for different reactivities: electron-donating substituents (i.e. methoxy- or hydroxyl-group) seem to increase the reactivity of benzoic acid, whereas the presence of electron-withdrawing substituents, such as nitro-group, decreases the reactivity of the molecule. Hydroxylation of the aromatic ring is an important pathway during the CWO of BA.

Studies of VOCs removed from packed-bed absorber by experimental design methodology and analysis of variance

Indoor air quality is affected by volatile organic compound (VOC) pollutants and these are often emitted by furniture and building materials. To enhance indoor air quality, removing VOCs from indoor environment is an important task. Triethylene glycol (TEG) solution was used as working solution to absorb VOCs from ambient air in this study. Plastic 5/8 in. polaring-type was packed in the packed-bed absorber, and the packed length was about 34 cm. Toluene, methanol, ethyl ether, and methyl-ethyl ketone were absorbed separately by TEG solution. Two-level factorial experimental design methodology was applied to schedule the operating variables in the experiment. The advantage of experimental design methodology is to obtain reasonable experimental results with fewer experimental runs. In addition, the analysis of variance (ANOVA) was used to analyze the effect of operating variables (factors) on mass transfer coefficient (response). The p-value was used to assess the mass transfer performance of VOCs absorbed by packed-bed absorber. From experimental results, effect of air flux on mass transfer coefficient was significant except for methanol because the p-values were smaller than 0.1 for toluene, ethyl ether, and ketone. For VOCs concentration, the effect of methanol concentration on mass transfer coefficient was extremely significant; the effect of concentration of ethyl ether was very significant; the effect of concentration of toluene was significant; the effect of methyl-ethyl ketone was insignificant. Since all the p-values were smaller than 0.01 for liquid flux, the effect of liquid flux on mass transfer coefficient was very significant. By analyzing the factorial interaction, the factorial couples, toluene concentration × liquid flux, TEG concentration × methanol concentration, TEG concentration × ethyl ether concentration, and ketone concentration × liquid flux can be chosen as main variables to operate the absorption system for absorption of toluene, methanol, ethyl ether, and ketone to acquire the desired mass transfer coefficient.

Simultaneous photocatalytic oxidation of As(III) and humic acid in aqueous TiO 2 suspensions

The simultaneous photocatalytic oxidation of As(III) and humic acid (HA) in aqueous Degussa P25 TiO 2 suspensions was investigated. Preliminary photocatalytic studies of the binary As(III)/TiO 2 and HA/TiO 2 systems showed that As(III) was oxidized more rapidly than HA and the extent of photocatalytic oxidation of each individual component (i.e. As(III) or HA) increased with decreasing its initial concentration and/or increasing catalyst loading. The simultaneous photocatalytic oxidation of As(III) and HA in the ternary As(III)/HA/TiO 2 system showed that both As(III) and HA oxidation was reduced in the ternary system compared to the corresponding binary systems. The effect of operating conditions in the ternary system, such as initial As(III), HA and TiO 2 concentrations (in the range 3–20 mg/L, 10–100 mg/L and 50–250 mg/L respectively), initial solution pH (3.6–6.7) and reaction time (10–30 min), on photocatalytic As(III) and HA oxidation was assessed implementing a two-level factorial experimental design methodology. Seven and ten factors were found statistically important in the case of photocatalytic As(III) and HA oxidation respectively. Based on these statistically significant factors, a first order polynomial model describing As(III) and HA photocatalytic oxidation was constructed and a very good agreement was obtained between the experimental values and those predicted by the model, while the observed differences may be readily explained as random noise.

Factorial experimental design for recovering heavy metals from sludge with ion-exchange resin

Wastewaters containing heavy metals are usually treated by chemical precipitation method in Taiwan. This method can remove heavy metals form wastewaters efficiently, but the resultant heavy metal sludge is classified as hazardous solid waste and becomes another environmental problem. If we can remove heavy metals from sludge, it becomes non-hazardous waste and the treatment cost can be greatly reduced. This study aims at using ion-exchange resin to remove heavy metals such as copper, zinc, cadmium, and chromium from sludge generated by a PCB manufacturing plant. Factorial experimental design methodology was used to study the heavy metal removal efficiency. The total metal concentrations in the sludge, resin, and solution phases were measured respectively after 30 min reaction with varying leaching agents (citric acid and nitric acid); ion-exchange resins (Amberlite IRC-718 and IR-120), and temperatures (50 and 70 °C). The experimental results and statistical analysis show that a stronger leaching acid and a higher temperature both favor lower heavy metal residues in the sludge. Two-factors and even three-factor interaction effects on the heavy metal sorption in the resin phase are not negligible. The ion-exchange resin plays an important role in the sludge extraction or metal recovery. Empirical regression models were also obtained and used to predict the heavy metal profiles with satisfactory results.

Low pressure microwave plasma assisted chemical vapor deposition (MPCVD) of diamond coatings on silicon nitride cutting tools

Diamond coatings were deposited on commercial silicon nitride (Si 3N 4) cutting tools by low pressure microwave plasma assisted chemical vapor deposition (MPCVD) at various processing conditions to assess the quality and adhesion of diamond coatings. A four-factor, three-level fractional factorial experimental design methodology was used to determine the significance of the process variables, such as the microwave chamber pressure, substrate temperature, microwave power and % CH 4 concentration in the hydrocarbon–hydrogen mixture. The reactor pressure was found to have the strongest influence on nucleation followed by the temperature and the % CH 4 concentration. Microwave power was found to have a minimum influence on nucleation. It was also found that nucleation density decreases with increase in pressure, while it increases with increase in the % CH 4 concentration. Substrate temperature and % CH 4 concentration were found to be the most crucial parameters dictating the overall growth rate as well as the quality of the diamond films. Diamond-coated Si 3N 4 tools were characterized by μ-Raman spectroscopy and scanning electron microscopy. The former was used to assess the quality of the diamond coatings (phase purity as well as the amount of amorphous carbon associated with the sp 2 structure) as well as the residual stresses on the tools. The relative intensity of the non-diamond to the crystalline diamond was found to decrease with increase in the microwave chamber pressure. Higher microwave power was found to increase the intensity of the crystalline diamond and decrease the non-diamond peak intensity. The morphology of diamond coatings was assessed using an SEM. The diamond films deposited were qualitatively assessed for adhesion using the Rockwell hardness tester with a Brale indenter and an abrasion wear tester. A chamber pressure of ∼20 torr (2.65 kPa); a microwave power of ∼1000 W; a CH 4 concentration of 0.5–1%; and a substrate temperature in the range of 850–900°C, were identified as the optimum deposition conditions for producing good quality diamond coatings on Si 3N 4 substrate.