Three-level Full Factorial Design Research Articles

Dually Cross-Linked Core-Shell Structure Nanohydrogel with Redox-Responsive Degradability for Intracellular Delivery.

A redox-responsive nanocarrier is a promising strategy for the intracellular drug release because it protects the payload, prevents its undesirable leakage during extracellular transport, and favors site-specific drug delivery. In this study, we developed a novel redox responsive core-shell structure nanohydrogel prepared by a water in oil nanoemulsion method using two biocompatible synthetic polymers: vinyl sulfonated poly(N-(2-hydroxypropyl) methacrylamide mono/dilactate)-polyethylene glycol-poly(N-(2-hydroxypropyl) methacrylamide mono/dilactate) triblock copolymer, and thiolated hyaluronic acid. The influence on the nanohydrogel particle size and distribution of formulation parameters was investigated by a three-level full factorial design to optimize the preparation conditions. The surface and core-shell morphology of the nanohydrogel were observed by scanning electron microscope, transmission electron microscopy, and further confirmed by Fourier transform infrared spectroscopy and Raman spectroscopy from the standpoint of chemical composition. The redox-responsive biodegradability of the nanohydrogel in reducing environments was determined using glutathione as reducing agent. A nanohydrogel with particle size around 250 nm and polydispersity index around 0.1 is characterized by a thermosensitive shell which jellifies at body temperature and crosslinks at the interface of a redox-responsive hyaluronic acid core via the Michael addition reaction. The nanohydrogel showed good encapsulation efficiency for model macromolecules of different molecular weight (93% for cytochrome C, 47% for horseradish peroxidase, and 90% for bovine serum albumin), capacity to retain the peroxidase-like enzymatic activity (around 90%) of cytochrome C and horseradish peroxidase, and specific redox-responsive release behavior. Additionally, the nanohydrogel exhibited excellent cytocompatibility and internalization efficiency into macrophages. Therefore, the developed core-shell structure nanohydrogel can be considered a promising tool for the potential intracellular delivery of different pharmaceutical applications, including for cancer therapy.

Micro-patterned graphite electrodes: An analysis and optimization of process parameters on hydrogen evolution in water electrolysis

The aim of this investigation is to enhance the hydrogen production rate using developed micro-patterned graphite electrode in water electrolysis method. Alkaline sodium hydroxide was used as an electrolyte for enhancing the hydrogen production through the continuous electrolysis process. The Box-Behnken design based four-factor three-level full factorial design was utilized to develop the regression model for the hydrogen production process. The response surface methodology was used to analyze the combined effects of voltage supplied, electrolyte molarity and electrode distance on hydrogen production rate. The maximum hydrogen production rate of 2.3 ml/min was achieved under the optimum conditions such as supply voltage of 2 V, electrolyte molarity of 0.3 M and an electrode distance of 10 cm. The predicted regression equation for the hydrogen production process showed positive effect with the experimental value. Also, the individual parameter on hydrogen yield has been evaluated using ANOVA analysis. The coefficient of determination (R2) of 0.98 showed that the model obtained was highly significant to predict the response accurately with below 2% error. The surface of the graphite microstructure considerably influenced the reaction of the electrolysis on hydrogen evolution rate. The micro-patterned electrode was compared with the planar electrode on the hydrogen production rate at optimum conditions and found a 60% increase in yield.

Analysis of faults in rotor-bearing system using three-level full factorial design and response surface methodology

This article presents the experimental and statistical methodology for localized fault analysis in the rotor-bearing system. These defects on outer race, on inner race, and on a combination of ball and outer race are considered. In this study speed, load and defects were considered as the essential process variables to understand their significance and effects on vibration response for the rotor-bearing system. Three factors at three levels were considered for experimentation, and the experiment was designed for L27 based on design of experiments (DOE) methodology. From the experiments, the vibration response results are recorded in terms of root mean square value for the analysis. Response surface methodology (RSM) is used for identifying the interaction effect of varying process parameters upon the response of vibrations by response surface plot. The rotor-bearing test setup is used for experimentation and is analyzed by using DOE. This study establishes the prediction of fault in the rotor-bearing system in combined parametric effect analysis and its influence with DOE and RSM.

Improving Resolution of Isomeric Flavonoids and Their Glycosides Using Two-Dimensional Liquid Chromatography Coupled With High-Resolution Mass Spectrometry

The separation of isomers is one of the key issues in analysing complex natural matrices, thus commanding a higher separating power from the applied analytical system. In this study, 42 common flavonoid glycosides from three key subclasses (flavanones, flavones, flavonols) were analysed in three steps to maximise chromatographic and spectrometric resolution via: (1) C18 liquid chromatography (LC) coupled to a quadrupole time-of-flight mass spectrometer (QTOF/MS), (2) tandem mass spectrometry (MS/MS), and (3) two-dimensional LC with heart-cutting for specific regions of co-elution. While the LC-QTOF/MS step was found to separate the majority of flavonoid glycoside isomers, some isomers with identical accurate mass were not resolved. Following this, increased spectrometric resolution was achieved with MS/MS; however, this technique was not suitable for particularly challenging isomers that were also identical in aglycone and saccharide structure. Furthermore, a heart-cutting method was developed using a three-level full-factorial design to separate such challenging isomers, and satisfactory resolution was obtained for the targeted isomers (R > 2.00) with reasonable efficiency (total run time < 25 min) and repeatability (RSD < 2%). In conclusion, the developed strategy highlights the significance of combining high-resolution mass spectrometry with chromatographic separation for added confidence in the identification of isomers.

Degradation of p-Nitrotoluene in aqueous environment by Fe(II)/Peroxymonosulfate using full factorial experimental design

ABSTRACT In this project, the removal of p-Nitrotoluene (PNT) in typical synthetic wastewater was investigated using Peroxymonosulfate (PMS) motivated by Ferrous Ion. The PNT was degraded by sulfate and hydroxyl radicals. The effect of various factors such as ferrous ion and PMS concentrations, and pH on the removal of PNT was studied. Three-level full Factorial design of experiments (FFD) was employed for experimental design and statistical analysis. It was revealed that the PMS and ferrous ion concentrations and quadratic terms were statistically significant while the factor interactions were insignificant model terms. Increasing the PMS and ferrous ion concentrations enhanced the PNT removal efficiency to some extent. The pH had two-contrast influence and the neutral pH was the best. The most significant term was the concentration of ferrous ion, which influenced greatly on PMS and considerably caused a change in the PNT removal efficiency. R-squared, as a measure of the amount of variation around the mean explained by the model was 0.9827. The maximum removal condition was obtained at pH of 7, ferrous ion concentration of 12 mM and PMS concentration of 25 mM. The maximum removal of PNT and COD was achieved as 96% and 67%, respectively.

Nanostructured lipid carrier-based smart gel: a delivery platform for intra-articular therapeutics

The promising potential of nano-structured lipid carrier (NLC) polymeric gel of CUR as an effective treatment for rheumatoid arthritis by intra-articular route of administration was investigated. NLC composed of cetylpalmitate, Labrafac PG & Captex 200, Tween 80 and Labrasol. The hot homogenization method employed by melt ultrasonication was used. The formulated NLC dispersions were characterized and were suitably dispersed into the matrix of pluronic F-127(PLF-127) and pluronic F-68 (PLF-68). A two-factor three-level full factorial design was employed to deduce the optimal concentrations of PLF-127 and PLF-68. The optimized formulations were sterilized by gamma radiation. The formulated NLC smart gels were characterized and evaluated for various parameters. The efficacy evaluation by antigen-induced monoarthritis model and biocompatibility testing by histopathological studies was performed. Formulated NLCs exhibited an average particle size of 165.12 nm, entrapment efficiency of 72.15%, and zeta potential of −21.67 mV. The optimized CUR-NLC smart gel was demonstrated to have a sol–gel transformation at 33.21 °C and 94.32% drug release at 84 h. NLC’s which were sterile and easily syringeable, continued to remain within the colloidal range. CUR-NLC smart gels were found to be biocompatible and showed a significant reduction in rat knee joint inflammation compared to free drug.

Modeling and multi-objective optimization of cutting parameters in the high-speed milling using RSM and improved TLBO algorithm

The main purpose of the present paper is to study the cutting parameter optimization technology by combining the response surface methodology (RSM) with the improved teaching–learning-based optimization (ITLBO) algorithm to obtain the best cutting parameters under multi-objective conditions. Considering the factors of cutting parameters which affect cutting force and surface roughness such as cutting speed, feed per tooth, axial depth of cut, and radial depth of cut, a series of milling experiments are carried out based on four-factor and three-level full factorial experiment design to measurement the cutting force and surface roughness. Based on the collected experimental results, a cubic polynomial regression prediction model for cutting force and surface roughness were established based on the RSM, respectively. Experiments verify that the error of the cutting force prediction model is 0.2–8.04% and 1.36–5.86% for the error of the surface roughness prediction. RSM model is further interfaced with the ITLBO algorithm to optimize the cutting parameters for the multi-objective of cutting force, surface roughness, and processing rate. The optimization experiment results show that cutting force increased by 2.70%, surface roughness decreased by 6.63%, and material removal rate has increased by 49.42%. It indicates that the cutting parameter optimization method based on RSM–ITLBO is effective.

Effects of Portland Cement and Polymer Powder on the Properties of Cement-Bound Road Base Mixtures.

This article presents the test results for the physical and mechanical properties and fracture toughness of polymer-modified hydraulically-bound mixtures (HBM) produced with Portland cement for road base layers. The modifier used was a redispersible polymer powder (RPP) based on a vinyl ethylene acetate (EVA) copolymer obtained by spray drying. A three-level full factorial design with two factors was applied to determine the contents of Portland cement and polymer powder in the cement-bound mixture (CBM). Both Portland cement and polymer powder were added at three levels: 0%, 2%, and 4%. The assessment included basic physical properties (water absorption, density, and bulk density) and mechanical properties (stiffness modulus, axial compressive strength, and indirect tensile strength) of the CBM. Particular attention was paid to the assessment of fracture toughness in the semi-circular bending test. The results of the research show that polymer powder positively influenced the mechanical properties of CBM by improving its cohesion while maintaining its stiffness. Another benefit coming from the use of polymer powder was the CBM’s increased resistance to cracking, which is the desired characteristic from the perspective of pavement durability.

Prediction of cutting forces in drilling AL6082-T6 by using artificial neural networks

This research investigates the comparison of the thrust force (Fz) and cutting torque (Mz) predictive models based on artificial neural networks (ANN). The models were developed based on three-level full factorial design of experiments conducted when drilling of Al6082-T6 alloy material with cutting speed, feed rate and tool diameter as the process parameters. The predictive ANN models of thrust force (Fz) and cutting torque (Mz) were developed using a multilayer feed forward neural network, trained using an error back propagation learning algorithm. The developed models are shown capable of predicting them (Fz and Mz) to a great level. The confirmation experiments provided favorable results with accuracy of 4% and 4.5%, for the thrust force (Fz) and the cutting torque (Mz) respectively. Furthermore the R coefficient for the prediction model of the thrust force is 0.99608 and 0.9946 for the cutting torque. As a result they can be considered as very accurate and appropriate for their prediction. This study promotes the better machining quality and the sustainability of the process that are achieved at the same time

Mechanochemical Synthesis of Zinc Oxide Nanoparticles and their Antibacterial Activity against Escherichia Coli

Crystalline ZnO nanoparticles were synthesized by a mechanochemical method using zinc acetate dihydrate and sodium hydroxide as starting materials, and cetyl trimethylammonium bromide (CTAB) as a protective agent. Mechanochemical activation of the solid-state reaction was achieved at low temperatures in a rapid laboratory ball mill. A three-level full factorial experimental design was used to investigate the effect of milling time and surfactant ratio on ZnO crystallite size. The product powders were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The crystallite size of ZnO samples estimated from XRD is consistent with the SEM images and found to be less than 40 nm. The crystallite size of the ZnO decreased as the surfactant ratio increased. There is an optimal milling time of 60 minutes in order to obtain ZnO nanoparticles with the smallest average grain size. The antibacterial activity of the obtained products against Escherichia coli (E. coli) was examined, and the minimum inhibitory concentration value was 5 mg/mL. ZnO synthesized by this simple method can be considered potentially as an effective bactericidal agent.

Employing UV/peroxydisulphate (PDS) activated by ferrous ion for the removal of toluene in aqueous environment: electrical consumption and kinetic study

ABSTRACT The main purpose of this project was to explore the removal of toluene (TOL) from a typical synthetic wastewater by peroxydisulfate (PDS) activated by ferrous ion and ultra violet (UV) light. The effect of various factors such as PDS and ferrous ion concentration and pH on the removal of TOL was studied. Three-level full factorial design of experiments was employed for experimental design and statistical analysis. It was revealed that the studied variables and quadratic terms were statistically significant while the interactions were insignificant. Increasing the PDS and ferrous concentration enhanced the TOL removal efficiency, but it was decreased with increase in pH. The most significant term was ferrous ion concentration which influenced greatly on TOL removal efficiency. The optimum condition was obtained at pH of 4, ferrous ion concentration at 0.7 mM and PDS concentration of 1.5 mM. The maximum removal of TOL and COD were achieved as 97.6 and 65%, respectively, after 45 min of reaction. Besides, the kinetic study showed pseudo-first-order reaction for the removal of TOL. So, as a figure-of-merit, the ‘electrical energy per order’ was determined at 7.39 kWhm−3 order−1, showing little electrical energy intake and high economical income.

Refined experimental design and response surface methodology workflow using proxy numerical models for probabilistic geothermal resource assessment

Numerical reservoir modelling is the most reliable geothermal resource assessment tool for quantifying power production at a sustainable level, but it does not mesh well with the Monte Carlo method for quantifying uncertainties. Building proxy numerical models using Experimental Design (ED) and Response Surface Methodology (RSM) workflows may provide a solution. The present study attempts to improve existing approaches through the use of the two-level and three-level Full Factorial and Box-Behnken designs. The improved workflow yields consistent results for both the Ohaaki and Rotorua geothermal fields suggesting that probabilistic MWe output distribution is between P90 to P10 of the widely used volumetric method.

Deferoxamine-loaded transfersomes accelerates healing of pressure ulcers in streptozotocin-induced diabetic rats

Diabetic nonhealing ulcers are the leading cause of nontraumatic amputations. An increased cancer risk has been found in patients treated with current therapies such as becaplermin gel. Therefore, an urgent need exists for novel approaches to control delayed ulcer healing. HIF-1α mediates adaptive responses to hypoxia by regulating angiogenesis, proliferation, migration, and cell survival. However, its function is impaired by hyperglycemia. Deferoxamine (DFO) might be an effective HIF-1α stabilizer by inhibiting PHD enzyme through the prevention of iron release in diabetic tissue. Herein, transfersomes were used as nanocarriers for DFO. The system depends on the ability of transfersomes to enhance the penetration of the large hydrophilic drug, DFO through the skin and sustain its release by applying a two-factor, three-level full factorial design to optimize entrapment efficiency, particle size, zeta potential and in vitro drug release. The soybean phosphatidylcholine (SPC) amount and the ratio of surfactant to SPC were selected as independent variables. The formulations had an entrapment efficiency range of 54.46–91.56%, particle size range of 109.2–265.6 nm, polydispersity index values less than one and negative zeta potential range of −17.53 to −29.03 mV. In vitro study revealed that the DFO-loaded transfersomal gel has uniform distribution of DFO, applicable pH, and suitable viscosity and found effective in sustaining DFO release. Moreover, in-vivo study of the optimized formulation demonstrated cutaneous wound healing potential in rats’ diabetic pressure ulcers. Overall, DFO-loaded transfersomal gel shows promise as a potential therapy for the treatment of human diabetic ulcers.

Effect of electrodeposition parameters and surface pretreatment on the electrochemical hydrogen production using nickel-plated stainless steel electrodes

In this work, the effect of time, potential and concentration of Ni2+ on the amount of nickel deposited during the preparation of nickeled electrodes by electrodeposition, as well as on the concentration of hydrogen produced by electrolysis using such electrodes, was analyzed. Untreated and sandblasted AISI/SAE 304 stainless steel expanded meshes were used as support. The reduction potential of the Ni2+/Ni0 in the Watts bath was determined by cyclic voltammetry (CV) at 0.70 V vs. Ag/AgCl. Three-level full factorial design (33) was employed to analyze principal effects and interactions between the electrodeposition parameters on the weight of nickel coating. The highest weight of nickel coating (0.41 g) was obtained at 2.3 V for 20 min, from 1.466 M Ni2+ Watts bath. Hydrogen production was evaluated by micro-electrolysis and macro-electrolysis studies. Three-level full factorial design (33) was employed to analyze principal effects and interactions between the electrodeposition parameters on the amount of hydrogen produced. The highest amount of hydrogen produced (2530.5 μmol), at 2.0 V after 30 min, was obtained with the as-prepared electrode with the highest weight of nickel coating. Morphologic and elemental analyses of this electrode by field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (FESEM EDS) showed a coating with a rough surface formed by coarse grains, having a thickness of 46.92 μm and a nickel composition of 99.29 at.%.

Optimization and reaction kinetics analysis for phosphorus removal in struvite precipitation process.

As a promising strategy to remove and recover phosphorus from wastewater, optimization of the struvite (MgNH4 PO4 .6H2 O) precipitation parameters is required to achieve desirable phosphorus removal efficiency. To tackle the challenges upon the precipitation optimization methods as three-level full factorial designs, and central composite design as well, Box-Behnken design was implemented to optimize different reaction parameters for phosphorus removal and recovery during struvite precipitation in the current study. Moreover, the reaction orders and the rate equation were all determined to reveal the reaction kinetics parameters of struvite precipitation. The results showed that the optimal operating parameters of pH, Mg/P ratio and N/P ratio were 9.82, 1.45, and 4.00, respectively, by which more than 95% of phosphorus removal efficiency could be achieved. In addition, it was found that pH and pH/(N/P) had the most influence on phosphorus removal efficiency among different individual factors and interactive items, respectively. The partial orders of PO4 -P, Mg2+ , and in kinetic rate equation were determined as 1.586, 0.930, and 1.236 while the rate constant k was 0.0167±0.0014mM-2.752 per minute by differential method. PRACTITIONER POINTS: Different reaction parameters were optimized by Box-Behnken design. pH and pH/(N/P) had the most influence on phosphorus removal efficiency among different individual factors and interactive items. The reaction orders and the rate equation were all determined to reveal the reaction kinetics parameters.

A full 34 factorial experimental design for the low energy building’s external wall

The low energy building concept is based on improving the building envelope to reduce heating and cooling loads. Improvements in building envelopes depend not only on climatic conditions but also on insulation. In this study, the thermal performance of external walls was studied by using a three-level full factorial statistical experimental design. An opaque wall in low energy buildings was chosen in order to study the effect of selected factors of city (A), orientation (B), insulation location (C), and month of the year (D) on heat loss or gain. A software was used to calculate the ANOVA table. As a result, all three factors of months of the year, city and orientation of the building fa?ade were found to be significant factor effects for heat transfer. Two-factor interactions of AB, AD, BD, and CD were found to be significant. Therefore, the effects of season, location and orientation were successfully shown to be effective parameters.

Low Velocity Impact Performance and Puncture Resistance of Nonwoven Geotextiles with the Change of Process Parameters

In the present work, an attempt has been made to study the effect of structural changes on the sustainable properties of needle punch nonwoven geotextile. There are two important process parameters, which influence the structure significantly. The parameters are punch density and depth of penetration of the needle. This research work is designed by considering the two parameters. Whereas, three-levels of each parameter taken and nine samples prepared by using two-factor three-level full factorial design. The structural analysis was carried out by an image analysis technique. All measured physical and mechanical properties of nonwovens have a strong correlation with the structural parameter. The significant effect noticed on fabric thickness, tensile strength, pore diameter, puncture resistance and impact resistance with the varying considered parameters; punch density and needle depth penetration.

Electro-Discharge Machining Performance of Nimonic 80A: An Experimental Observation

The present work reports electro-discharge machining (EDM) performance of superalloy Nimonic 80A. Experiments are conducted using a two-factor three-level full factorial design of experiment in consideration with two important electrical parameters: peak discharge current and pulse-on duration. Machining performance is evaluated in purview of material removal efficiency, rate of electrode wear, and surface integrity of the EDMed part product. Apart from morphological study, surface topographic measures including surface roughness, impact of surface cracking, white layer thickness, material migration, phase alteration, and micro-indentation hardness are studied in detail. Results of qualitative analysis on crater morphology are correlated with roughness value of the machined specimen. Effects of peak current and pulse-on time on influencing EDM performance indicators are also reported. An optimal parametric combination is determined for superior process performance. In doing so, utility theory is utilized to aggregate multi-performance characteristics to compute a unique index (called overall utility degree). The parametric combination which corresponds to maximum overall utility is assumed to be the best. It is determined that maximum material removal efficiency, minimal tool wear rate, and superior surface finish can be achieved at parameters setting: Ip = 35 A and Ton = 1000 µm. The said optimal setting corresponds to overall utility value of 6.53. Confirmatory test result yields: MRR = 9.05 × 10−3 g/s, TWR = 1.2 × 10−5 g/s, and Ra = 14.1 µm at optimal setting.

Statistical optimization of the photo-Fenton operational parameters with in situ ferrioxalate induction in the treatment of textile effluent

In this work, the photo-Fenton process with ferrioxalate induction has been applied to perform the degradation of the organic matter from a textile effluent based on a full factorial design in order to work at its optimized condition along with obtaining a low toxicity. Experimental tests based on a three-level full factorial design (FF 33) were performed, properly varying initial pH, Fe3+ ion concentration and H2O2 concentration and using COD and color removal as response variables. Additionally, 240-min UV irradiation and 150-rpm shaking speed were set at all runs. The FF 33 experimental data were statistically represented by a quadratic polynomial function validated by the ANOVA test, suggesting the individual and combinate effects of fundamental parameters on removals. In this context, an improvement on COD removal and discoloration up to 93 and 99%, respectively, was found. The best condition of 8000 mg L−1 H2O2, 170 mg L−1 Fe3+ and initial pH 2.8 was applied to assess the toxicity effect. An extending on experiment time of about 120 min was suggested by Artemia salina-based bioassays to get a lower toxicity in environmental safety context. Finally, the photo-Fenton process with ferrioxalate induction was verified to favor and improve the pollutant degradation with higher COD removals, faster reaction kinetics and a greater availability of iron ions in comparison with the conventional photo-Fenton reaction. Besides, treated effluent with evident reduction in toxicity could be disposed without affecting the water body quality.

Selective photocatalytic oxidation of cyclohexanol to cyclohexanone: A spectroscopic and kinetic study

In this work, spectroscopic and kinetic studies were performed on photocatalytic oxidation of cyclohexanol to cyclohexanone. The photocatalytic experiments were performed according to a three-level full factorial design and the rate of cyclohexanone production was determined by HPLC analysis. In situ ATR-FTIR analysis of the photocatalytic reaction revealed that cyclohexanol can be selectively converted to cyclohexanone, without the formation of significant amounts of carbonates and carboxylates. A reaction mechanism based on different steps from charge separation to cyclohexanone molecule formation is proposed. The results were utilized to determine the kinetic parameters (with the help of genetic algorithm) and validate the model. The developed kinetic model illustrates that the rate of cyclohexanone production increases as a power function with respect to the light intensity and decreases as an exponential function with respect to time. An excellent selectivity of cyclohexanone was confirmed by spectroscopic and chromatographic studies. This study demonstrates that photocatalysis can be a promising technology for formation of cyclohexanone from cyclohexanol.