Half-fractional Factorial Design Research Articles

Determination of Atropine by HPLC in Plant of Datura by Liquid-Liquid Extraction and Magnet Solid-Phase Extraction.

Atropine is a tropane alkaloid found in abundance in Datura plant. We used two liquid-liquid extraction methods and magnet solid-phase extraction to compare the amount of atropine in these two types of plants (Datura innoxia and Datura stramonium). The surface magnetic nanoparticle Fe3O4 correction with an amine and dextrin, and finally, magnetic solid-phase extraction Fe3O4@SiO2-NH2-dextrin (MNPs-dextrin), was prepared. We determined the effect of significant parameters in the removal step and optimization of atropine measurements with half-fractional factorial design (25-1) and response surface methodology via central composite design. The optimum conditions are for desorption solvent = 0.5mL methanol and desorption time of 5min. We obtained an extraction recovery of 87.63% with a relative standard deviation of 4.73% via six frequented measurements on a 1μgL-1 atropine standard solution based on the optimum condition. Preconcentration factors for MNPs are 81, limit of detection = 0.76μgL-1 and limit of quantitation = 2.5μgL-1.

A statistical analysis of the effect of confining pressure on deformation characteristics of HMA mixtures in the modified wheel track testing

Permanent deformation in the form of rutting is a critical mode of failure observed in flexible pavements. While several research have been conducted to develop multiple tests for the characterisation of permanent deformation, little information is obtainable from the existing literature on how the factors or the interaction of the factors from these tests affect the permanent deformation behaviour in a simulative test, such as the wheel tracker. This research focuses on statistical analysis and ruggedness testing of the factors affecting the permanent deformation behaviour of asphalt mixes tested in the Modified Wheel Tracker (MWT). The analysis involved five factors in total, each at two levels. These factors are binder type, voids in total mix (VTM %), nominal maximum aggregate size, temperature, and confining pressure. The study utilised half-fractional factorial design in accordance with ASTM E1169-20. Significant parameters were determined through statistical analysis and regression models were proposed. The contour plots provided various combinations of the most significant factors for the corresponding responses. Based on the statistical analysis of the experiments conducted without any confinement, temperature, amongst all other factors, was found to impose the greatest effect on the permanent deformation behaviour based on vertical and horizontal FN Indices. Experiments with controlled confinement show that “confining pressure” is the most significant factor for the rutting parameters. The sensitivity analysis points out that to maintain the vertical deformation at 2000 cycles to be in the range ± 25% from the model, the confining pressure and temperature should be controlled within the range ± 25% and ± 5%. The use of the MWT shows that long-term rutting development can well be predicted from rutting at 2000 cycles using linear and exponential models.

Fractional factorial design to study admixtures used for 3D concrete printing applications

• The methodology reduces the material required to assess the importance of admixtures. • The same conclusions were drawn following a full and a fractional factorial plan. • Half of the experiments could be avoided, reducing the amount of resources needed. Mortar mix design for 3D printing applications is growing at a fast pace. The array of available materials proposed for such an application creates a lot of opportunities for mix designs. However, it makes the selection between the available options an onerous task to fulfill. The objective of this study is to reduce the material required to assess the importance of admixtures on fresh properties of cement-based mixes. Among the competing objectives required in a mix design for 3D printing applications, the dynamic yield stress and the flow are investigated. The dynamic yield stress of the cement-paste mixtures is measured by a rotary rheometer and the ASTM C1437 flow test is used to measure the spread of the mortar mixes. The spread is correlated with the pumpability of the mixes, whereas the dynamic yield stress indicates the extrudability and the structure deformation of the mixes. The cement used is blended with silica fume. Fine local sand is selected and the admixtures used are a superplasticizer based on synthetic organic polymers, a biopolymer polysaccharide viscosity modifying agent, a nanoclay made of magnesium silicate, crystalline calcium silicate hydrates, and an accelerator with a water-reducing effect. Design of experiments methods are employed. To evaluate the influence of each admixture, the main effects and interactions are measured and the probability plots are graphically illustrating the results. First, an analysis is made on a two-level full factorial design with four factors. The results of the analysis are then compared with a half-fractional factorial design of a resolution IV. A fractional factorial design accurately discriminates the factors and reduce the number of experiments in mortar mix designs for 3D concrete printing applications.

Central fixation element type and length affect glenoid baseplate micromotion in reverse shoulder arthroplasty.

Reverse shoulder arthroplasty (RSA) is commonly used to treat patients with rotator cuff tear arthropathy. Loosening of the glenoid component remains one of the principal modes of failure and represents a significant complication that requires revision surgery. This study assessed the effects of various factors on glenoid baseplate micromotion for primary fixation of RSA. A half-fractional factorial design of experiment was used to assess 4 factors: central element type (central peg or screw), central cortical engagement according to length (13.5 or 23.5 mm), anterior-posterior peripheral screw type (nonlocking or locking), and cancellous bone surrogate density (160 or 400 kg/m3, 10 or 25 PCF). Glenoid baseplates were implanted into high- or low-density Sawbones rigid polyurethane foam blocks and cyclically loaded at 60° for 1000 cycles (500-N compressive force range) using a custom-designed loading apparatus. Micromotion at the 4 peripheral screw positions was recorded using linear variable differential transformers. Central peg fixation generated 358% greater micromotion at all peripheral screw positions compared with central screw fixation (P<.001). Baseplates with short central elements that lacked cortical bone engagement generated 328% greater micromotion than those with long central elements (P=.001). No significant effects were observed when varying anterior-posterior peripheral screw type or bone surrogate density. There were significant interactions between central element type and length (P<.001). A central screw and a long central element that engaged cortical bone reduced RSA baseplate micromotion. These findings serve to inform surgical decision making regarding baseplate fixation elements to minimize the risk of glenoid loosening and, thus, the need for revision surgery.

Increase in Fermentable Sugars of Olive Tree Pruning Biomass for Bioethanol Production: Application of an Experimental Design for Optimization of Alkaline Pretreatment

Olive Tree Pruning (OTP) biomass can be considered a suitable source of fermentable sugars for the production of second-generation bioethanol. The present study proposes a remarkable alternative for the valorization of olive tree pruning residues. OTP biomass was processed using a sequential calcium hydroxide pretreatment/enzymatic hydrolysis. A 24–1 half fractional factorial design was adopted for the screening of process variables and a central composite design was used for the optimization stage. Temperature and lime loading resulted statistically significant. The following optimal conditions were obtained: 0.01 g of Ca(OH)2/g of dry material, 20 g of H2O/g of dry material at 160 °C for 2 h. The mathematical model that governs this alkaline pretreatment was obtained with a 76% adjusted determination coefficient, which means that it is a good representation of the process. Under optimal operating conditions, 13% of the cellulose and 88% of the hemicellulose was solubilized. Moreover, the fermentable sugar content increased 1800% compared with the initial conditions, obtaining 240 g of glucose per kg of OTP residue. The fermentable sugars obtained after the calcium hydroxide pretreatment and enzymatic hydrolysis of OTP biomass yielded 2.8 g of ethanol/100 g of raw material.

Evaluation of optimal conditions for anionic surfactant removal in wastewater

This study was conducted to find the optimal conditions for removing anionic surfactants in wastewater using the coagulant-flocculant method. Optimal conditions must be found to minimize the amount of metal materials that can cause secondary contamination and to improve performance. Five parameters were selected to investigate their influence on surfactant removal. The ranges of the independent variables were 0.5–5% for coagulant concentration, 0.1–1% for flocculant concentration, and 20–650 mg/L for surfactant concentration; the coagulant type was FeCl3·6H2O or Ca(OH)2; and the pH ranged from 2 to 10. The experimental results were analyzed with Minitab 19.1 to find the optimal conditions to maximize the removal rate of surfactant. In this study, a total of 20 experiments were carried out using a half fractional factorial design (FFD) including two center points with a resolution of 5 and a pseudo-center point. The results demonstrated that coagulant concentration, flocculant concentration, and pH were significant independent variables with respect to surfactant removal. The fitted regression equation confirmed that the surfactant removal rate was maximized when the coagulant concentration was 5%, the flocculant concentration was 0.1%, and the pH was 10.

Statistical analysis of one-pot lipase-catalyzed esterification of ϵ-caprolactone with methyl- -glucopyranoside and its extension

Abstract One-pot synthesis of oligomeric sugar ester was carried out by lipase-catalyzed esterification of e-caprolactone (ECL) with methyl- d -glucopyranoside (MGP) followed by the chain extension of ECL monomer/oligomer. Two-level half fractional factorial design was employed to analyse the effects of selected operating variables namely lipase loading (1.2–2.8% w/v), initial ECL (3.8–11.5% w/v), initial MGP (0.04–0.14% w/v), temperature (40–60 °C) and agitation (90–180 rpm) as a function of maximum dry weight (% w/v) of MGP-6-O-oligo-ECL. It was found that individual variables viz. lipase loading, initial ECL and temperature affect the maximum product formation. The interaction effects between variables indicated the presence of relationship among them. Spectroscopic authentication showed the presence of covalent bond between the hydroxyl group of MGP with carboxylic acid end group of ECL monomer/oligomer. Thermal analysis indicated three degradation stages of functionalized oligomer. The molecular weight analysis of the functionalized oligomer was observed at 1,655 g mol−1 with narrow PDI value of 1.36. Conversion of initial ECL was 90% compared to 14% of initial MGP.

Determination of selected antiretroviral drugs in wastewater, surface water and aquatic plants using hollow fibre liquid phase microextraction and liquid chromatography - tandem mass spectrometry

This work describes a simple and sensitive method for the simultaneous isolation, enrichment, identification and quantitation of selected antiretroviral drugs; emtricitabine, tenofovir disoproxil and efavirenz in aqueous samples and plants. The analytical method was based on microwave extraction and hollow fibre liquid phase microextraction technique coupled with ultra-high pressure liquid chromatography-high resolution mass spectrometry. A multivariate approach via a half-fractional factorial design was used focusing on six factors; donor phase pH, acceptor phase HCl concentration, extraction time, stirring rate, supported liquid membrane carrier composition and salt content. The optimal enrichment factors for emtricitabine, tenofovir disoproxil and efavirenz from aqueous phase were 78, 111 and 24, respectively. The analytical method yielded recoveries in the range of 86 to 111%, and quantitation limits for emtricitabine, tenofovir disoproxil and efavirenz in wastewater were 0.033, 0.10 and 0.53 μg L−1, respectively. The drugs were detected in most samples with concentrations up to 37.6 μg L−1 recorded for efavirenz in wastewater effluent. Roots of the water hyacinth plant had higher concentrations of the investigated drugs ranging from 7.4 to 29.6 μg kg−1. Overall, hollow fibre liquid phase microextraction proved to be an ideal tool for isolating and pre-concentrating the selected antiretroviral drugs from environmental samples.

Optimization Of Nickel Deposition On Boron Carbide Particles Using Design Of Experiments

Abstract Amount of nickel deposition on Boron Carbide particles used as reinforcements in Aluminium metal matrix composites plays a vital role on wettability and bonding properties. In this work an attempt is made to investigate the influence of different bathing conditions of nickel deposition using electroless process onto boron carbide particles with average particle size as 44 µm. Sensitization bath is controlled by SnCl2, Activation bath is controlled by PbCl2, Coating bath is controlled by NiSO4.6H2O and the pH value of the solution. Two levels for the four factors are considered for the study, using half fractional factorial design 24-1 with two replicate 8runs are conducted. Nickel deposition on the boron carbide particles is observed by SEM images of the powder samples and the weight percentage of the Nickel deposited is observed by EDS smart quant results. Experimental results were analysed to study the influencing factors on the process by Analysis of Variance using design expert software. From ANOVA it is observed that most influencing factors on the process are amount of NiSO4.6H2O, PdCl2 and interaction of SnCl2 and NiSO4.6H2O respectively. From the regression model confirmation test has conducted and verified for maximum nickel deposition on Boron Carbide particles.

Application of experimental design for the development of soft-capsules through a prilling, inverse gelation process

The aim of this research was to develop a robust process capable of producing soft-capsules with hydrophilic core for topical administration by means of an inverse gelation. While this method is extensively studied to prepare particles with oily content, its knowledge space in the case of the proposed application is limited. Therefore, a half-fractional factorial design with 5 factors at two levels with resolution V was employed, to meet the scientific requirements in accordance with the Quality by Design approach. Kojic acid, an unstable skin whitening agent, was selected as the active ingredient for its easy detectability. Soft-capsules where produced through a vibrating nozzle device, dripping a thickened calcium chloride solution into an alginate bath. The experimental design applied revealed the effect of several Critical Process Parameters such as the solution's composition, frequency and flow-rate onto Critical Quality Attributes of the produced soft-capsules as for example drug content, encapsulation efficiency, size, shape and mechanical strength. The overall knowledge gained through the DoE exercise showed that the inverse gelation process was capable of producing soft-capsules with the desired attributes, resistant enough to allow handling during storage, but also easily ruptured when applied onto the skin, without leaving residues.

Factors contributing to glenoid baseplate micromotion in reverse shoulder arthroplasty: a biomechanical study

Reverse shoulder arthroplasty (RSA) is typically performed in patients with cuff tear arthropathy. A common type of RSA baseplate has a central peg and 4 peripheral screws inserting into the glenoid surface. Baseplate failure is a significant postoperative complication that reduces prosthetic longevity and usually requires revision surgery. This study evaluated the contribution of mechanical factors on initial baseplate fixation. This study simulated glenoid baseplate loading in a RSA. A half-fractional factorial design was used to test 5 factors: bone density (160 or 400 kg/m3), screw length (18 or 36 mm), number of screws (2 or 4), screw angle (neutral or diverging), and central peg length (13.5 or 23.5 mm). Trials were cyclically loaded at a 60° angle with 500 N for 1000 cycles. Micromotion at 4 peripheral screw positions was analyzed using a multifactorial analysis of variance (P < .05). We found an increase in micromotion with 3 scenarios: (1) lower bone density at all screw positions; (2) shorter central peg length at the inferior, superior and anterior screws; and (3) shorter screw length at the inferior and anterior screws. There were interactions between bone density and screw length at the inferior and anterior screws and between bone density and central peg length at the inferior, superior, and anterior screws. Greater bone density, a longer central peg, and longer screws provide improved initial glenoid fixation in an RSA, whereas the number of screws, and the angle of screw insertion do not. These findings may help minimize baseplate failure and revision operations.

Non-Precious Group Metal Electrocatalysis of Sulfite Electro-Oxidation Reaction for Gold Electrowinning Processes

The electro-oxidation of sulfite and its radicals has a wide range of applications from gold electrowinning to wastewater treatment, hydrogen production and in the food industry (1-4). While efforts have been made to study the electro-oxidation of sulfite ions on noble metals (e.g. Au) as well as carbon surfaces, metal oxides in general have not been thoroughly investigated for this electrochemical reaction (1, 5). During gold recovery from thiosulfate solutions, Au+ ions are reduced to Au from the thiosulphate gold complex on the cathode while oxygen evolution occurs on the anode via the following reactions (6): Au(S2O3)2 3- + e- = Au + 2S2O3 -2, E0= 0.15 V (1) 4OH- = 2H2O + O2 + 4e-, E0= 0.4 V (2) To drive the cathodic reaction, high current densities are used, which result in high anodic potentials on the stainless-steel anodes. Such high anodic potentials may cause transpassive corrosion of the anode as well as significant, and undesirable, changes in solution chemistry (7). This study systematically investigated the effect of operating factors on the corrosion behavior of stainless steel anodes in thiosulfate solutions during gold electrowinning. Further, novel non-precious group materials such as manganese oxides and perovskites were used as electrocatalysts for sulfite electro-oxidation to ultimately enhance the activity and long-term durability of the anodes in the gold electrowinning process (8). A 2n half-fraction factorial design study was performed to find the effect of five important parameters involved in the gold electrowinning process (i.e. thiosulfate concentration, sulfite concentration, sulfate concentration, temperature and applied anodic current density), on the anodic potential of the stainless steel anode. As shown in the Fig. 1A, increasing the sulfite concentration and temperature of the gold electrowinning solution lead to a low anodic potential of 550 mV which is about 250 mV lower than the transpassive corrosion potential for the 316 stainless steel anodes. To further reduce the anodic potential and employ the high sulfite concentration (i.e. 3000-32000 ppm) in the gold electrowinning solution, non-precious metal oxides were tested to facilitate the electrowinning process by catalyzing the following sulfite electro-oxidation reaction instead of the oxygen evolution reaction (eq. 2): SO3 2- + 2OH- = SO4 2- + H2O + 2e-, E0= -0.93 V (3) Fig. 1B shows that a combination of manganese oxide and perovskite electrocatalysts provides promising electrocatalytic activity and durability for sulfite electro-oxidation (i.e. up to 500 mV lower onset-potential over 7 hours of testing at 3.5 mAcm-2) compared to the Ni, commercial Ag/AgO, Pt, carbon, commercial Pb-2 wt% Ag and stainless steel electrodes tested here. Fig. 1 A) Surface plot produced from the 2n half-fraction factorial design study on the effect of five electrowinning parameters on the performance of 316 stainless steel gold electrowinning anode. B) A comparison between the electrocatalytic activity of various electrocatalyst materials for sulfite electro-oxidation in a solution of 100 ppm NaCl + 3000 ppm Na2SO4 + 32000 ppm Na2SO3 at 3.5 mA cm-2 and 45 °C. All MnO2-based catalysts are under the license with Catalyst Square Materials Ltd (8).

Magnetic core micelles as a nanosorbent for the efficient removal and recovery of three organophosphorus pesticides from fruit juice and environmental water samples.

Sodium dodecyl sulfate coated amino-functionalized magnetic iron oxide nanoparticles were used as an efficient adsorbent for rapid removal and preconcentration of three important organophosphorus pesticides, chlorpyrifos, diazinon and phosalone, by ultrasound-assisted dispersive magnetic solid-phase microextraction. Fabrication of amino-functionalized magnetic nanoparticles was certified by characteristic analyses, including Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. Affecting parameters on the removal efficiency were investigated and optimized through half-fractional factorial design and Doehlert design, respectively. The analysis of analytes was performed by high-performance liquid chromatography with ultraviolet detection. Under the optimum conditions, extraction recoveries for 20ng/mL of organophosphorus pesticides were in the range of 84-97% with preconcentration factors in the range of 134-155. Replicating the experiment in above condition for five times gave the relative standard deviations <6%. The calibration curves showed high linearity in the range of 0.2-700ng/mL and the limits of detection were in the range of 0.08-0.13ng/mL. The proposed method was successfully applied for both removal and trace determination of these three organophosphorus pesticides in environmental water and fruit juice samples.

THE USE OF FACTORIAL DESIGN FOR ANALYSIS OF MERCURY REMOVAL EFFICIENCY USING PALM OIL FUEL ASH

A two-level half fractional factorial design was employed to evaluate the factors that have the greatest effect on the mercury removal efficiency. Several factors can influence the mercury removal using palm oil fuel ash (POFA). The aim of this study was to examine the main and interaction effects on mercury removal efficiency using POFA. The parameters which affect the mercury removal are pH (2 – 6), contact time (1 hr – 4 hr), initial concentration of the Hg2+ solution (1 mg/L – 5 mg/L), adsorbent dosages (0.10 g – 0.25 g) and agitation speed (100 rpm – 200 rpm) were investigated. Half factorial design using Response Surface Methodology (RSM) was used to determine the significant contribution of the above factors towards mercury removal efficiency. From the statistical analysis, the main factor of contact time and the interaction between adsorbent dosage and initial concentration of the Hg2+ resulted in the strongest effect on mercury removal. However, the interaction between agitation speed and pH was the least influencing factors. Based on the predicted and the experimental results presented, the experimental values were in good agreement with the predicted values proposed by the model with an error less than 10 % and proved to be an adequate model. The result indicated that fractional factorial design (FFD) was useful to improve the mercury removal efficiency by considering all the interactions of variables involved. In summary, this demonstrated that POFA could be potential as low-cost adsorbent for the removal of mercury.

Development of a low-serum medium for the production of monoclonal antibody against congenital adrenal hyperplasia by hybridoma culture

ABSTRACTStatistically designed experiments were used in developing a low-serum medium for the production of a diagnostic monoclonal antibody against congenital adrenal hyperplasia using hybridoma 192. A two-level half-fractional factorial design was used for screening six components (Minimum Essential Medium Eagle amino acids, 2-mercaptoethanol, ethanolamine, ferric citrate, zinc sulfate, and sodium selenite). The experimental design was then augmented to central composite design. The basal Dulbecco’s modified Eagle’s medium (DMEM; containing 4 mM L-glutamine, 1% antibiotic–antimycotic agent) supplemented with 0.4% by volume fetal bovine serum (FBS), 311.8 mM ferric citrate, 17.3 nM sodium selenite, and 4.5 mM zinc sulfate (LSD) was found to support the growth of the hybridoma. Specific cell growth rate in the LSD (0.033 ± 0.001/h) was slightly lower than in the control medium (i.e., basal DMEM supplemented with 2% FBS; 0.0045 ± 0.003/h). Nevertheless, the specific MAb production rate for LSD was higher (0.057 ± 0.015 pg/cell · h versus 0.004 ± 0.002 pg/cell · h in LSD and control, respectively). The antibody produced in the LSD showed high specificity and no cross-reactivity with the other structural resemblance’s steroid hormones, revealing no structural changes owing to the new medium formulation developed. The new medium formulation effectively reduced the medium cost by up to 64.6%.

Toward Active and Durable ORR/Oer Bifunctional Non-PGM Electrocatalysts: Surfactant-Assisted Electrodeposition of Mn Oxides

Development of novel bifunctional electrocatalysts with high electrocatalytic activity and durability for both oxygen reduction and evolution reactions (ORR and OER) is of outmost importance to grasp the full potential of the regenerative H2-O2 fuel cells and rechargeable metal-air batteries (e.g., Zn-air, Al-air, Mg-air, Li-air) as reliable and efficient energy conversion/storage systems. Manganese oxides have been on the spotlight as an attractive catalyst material due to cost competitiveness, environmental friendliness, natural abundance as well as excellent reactivity for ORR and to some extent for OER (1, 2). The physicochemical and electrochemical properties of MnOx are highly dependent on its morphology and crystallographic nature (3). The aim of this work is to provide a systematic study on finding an active nanostructured manganese oxide for both ORR and OER via anodic electrodeposition method. A comprehensive study has been performed to investigate the main and interaction effects of key electrodeposition factors that significantly influence the electrosynthesis of manganese oxides, i.e. Mn2+ concentration (C), applied anodic potential (E), temperature (T), surfactant type and concentration (S), on the bifunctional activity of MnOx using a two-level half-fraction factorial design. Sodium dodecyl sulfate (SDS) as anioinc, hexadecyl-trimethyl-ammonium bromide (CTAB) as cataionic and Triton X-100 as non-ionic surfactants were used in this study to electro-synthesize the nanostructured MnOx. Surface characterization methods including XPS and SEM have been employed to analyze morphology and Mn valance of the synthesized electrocatalysts. Fig. 1 shows the surface plots of three different responses studied here for the electrodeposited manganese oxides in presence of Triton X-100, correlating them to the most important factors and two-factor interactions based on the Pareto plots of estimates. In this case, high surfactant concentration together with low applied anodic potential is believed to bring the best ORR/OER bifunctional performances for the electrodeposited Mn oxides (Fig. 1A and 1B). Mn concentration was found to be an insignificant player. Temperature, on the other hand, is believed to have different effect depending on its value with high temperatures providing low ORR/OER potential window while low temperatures lead to high ORR/OER mass activities (Fig. 1). Triton X-100 samples provide best performing nano-sized structures with promising ORR and OER performances comparing to both noble metals and other non-precious metals, i.e. between 50 to 150 mV lower ORR overpotential (at -2 mA cm-2) comparing to CoMn2O4 and Core-Corona Structured Bifunctional Catalyst (CCBC) and min. 100 mV lower OER overpotential (at 2 mA cm-2) comparing to Ir, Ru and IrO2 (1, 2). Galvanostatic polarizations at 5 mA cm-2 showed low OER potentials of 490 mV (at t=2 hrs), about 40 mV lower than commercial MnOx, and degradation rate of 43 mV h-1, about 10 mV h-1 lower than its commercial counterpart. The surface modifications of MnOx via surfactant-assisted electrodeposition can help destabilizing the HOO(ads) and HO(ads) intermediates, breaking away from the linear scaling relationship between their binding energies as a major contributor to the ORR and OER overpotentials, enhancing the ORR and OER electrocatalytic activity of electrodeposited manganese oxides. The formation of hydrogen-bonded complexes, i.e. HO(ads)…H-OH, with specially configured water molecules called “activated water” (4), can further enhance the ORR activity of the catalysts, depending on the surface coverage of OH(ads) which is needed to provide sites for formation of HO(ads)…H-OH complexes.

Surfactant-Assisted Electrodeposition of Mn Oxides As Promising ORR/Oer Bifunctional Non-PGM Electrocatalysts: Factorial Design Study of the Electrodeposition Parameters

Development of novel bifunctional electrocatalysts with high electrocatalytic activity and durability for both oxygen reduction and evolution reactions (ORR and OER) is of outmost importance to grasp the full potential of the regenerative H2-O2 fuel cells and metal-air batteries (e.g., Zn-air, Al-air, Mg-air, Li-air) as beneficial energy conversion and storage devices. Manganese oxides have been on the spotlight as an attractive catalyst material due to cost-competitiveness, environmentally friendliness, natural abundance as well as excellent reactivity for ORR and to some extent for OER (1, 2). The physicochemical and electrochemical properties of MnOx are highly dependent on its morphology and crystallographic nature (3). The aim of this work is to provide a systematic study on finding an active nanostructured manganese oxide for both ORR and OER via anodic electrodeposition method. A comprehensive study have been performed to investigate the main and interaction effects of key electrodeposition factors that significantly influence the electrosynthesis of manganese oxides, i.e. Mn2+ concentration (C), applied anodic potential (E), temperature (T), surfactant type and concentration (S), on the bifunctional activity of MnOx using a two-level half-fraction factorial design. Sodium dodecyl sulfate (SDS) as anioinc, hexadecyl-trimethyl-ammonium bromide (CTAB) as cataionic and Triton X-100 as non-ionic surfactants were used in this study to electro-synthesize the nanostructured MnOx. Surface characterization methods including XPS and SEM has been employed to analyze morphology and Mn valance of the synthesized electrocatalysts. Fig. 1 shows the surface plots of three different responses studied here for the electrodeposited manganese oxides in presence of Triton X-100, correlating them to the most important factors and two-factor interactions based on the Pareto plots of estimates. The highest ORR mass activity can be achieved at high surfactant concentration and low temperature (Fig. 1-A). Moreover, low applied anodic potential was found to further improve the ORR mass activity of the electrodeposited samples. The same trend was observed for highest OER mass activity as it appeared at low applied anodic potential, high surfactant concentration and low temperature (Fig. 1-B). The lowest ORR/OER potential window of below 600 mV can be obtained at high surfactant concentration, low applied anodic potential but high temperature (Fig. 1-C). The temperature seems to be a defining factor for the bifunctional characteristics of electrodeposited manganese oxides with high temperatures providing low ORR/OER potential window while low temperatures lead to high ORR/OER electrocatalytic activities.

A Quality by Experimental Design Approach to Assess the Effect of Formulation and Process Variables on the Extrusion and Spheronization of Drug-Loaded Pellets Containing Polyplasdone® XL-10.

Successful pellet production has been reported in literature with cross-linked poly(vinylpyrrolidone), Polyplasdone® XL-10 and INF-10. In the present study, a quality by experimental design approach was used to assess several formulation and process parameter effects on the characteristics of Polyplasdone® XL-10 pellets, including pellet size, shape, yield, usable yield, friability, and number of fines. The hypothesis is that design of experiments and appropriate data analysis allow optimization of the Polyplasdone product. High drug loading was achieved using caffeine, a moderately soluble drug to allow in vitro release studies. A five-factor, two-level, half-fractional factorial design (Resolution V) with center point batches allowed mathematical modeling of the influence of the factors and their two-factor interactions on five of the responses. The five factors were Polyplasdone® level in the powder blend, volume of water in the wet massing step, wet mixing time, spheronizer speed, and spheronization time. Each factor and/or its two-factor interaction with another factor influenced pellet characteristics. The behavior of these materials under various processing conditions and component levels during extrusion-spheronization have been assessed, discussed, and explained based on the results. Numerical optimization with a desirability of 0.974 was possible because curvature and lack of fit were not significant with any of the model equations. The values predicted by the optimization described well the observed responses. The hypothesis was thus supported.

Effect of network infrastructure factors on information system risk judgments

Little is known about how perceived network topology factors, which are common components of information system risk metrics, impact human judgments of risk. Using a half-fractional factorial design, this study experimentally manipulated five perceivable network topology factors (network partitioning, network diversity, wireless status, network footprint and connectivity) to assess the relationship between these factors and network risk judgments. The consistency of network risk ratings and rankings were evaluated for each of the 16 network topologies across a sample of 55 network security professionals who reviewed these topologies. Three robust significant main effects (network partitioning, wireless status, and connectivity) and one significant interaction (network partitioning X wireless status) were found. While some topologies were consistently rated and ranked as significantly more risky than others, there was some variability in ratings at each main effect level as well as the spread of the mean ratings between the two main effect levels (e.g., wireless and wired). We discuss the implications of our findings with respect to network risk metric rigor.

Spray-dried amikacin sulphate powder for inhalation in cystic fibrosis patients: The role of ethanol in particle formation

A Central Composite Design (CCD) was applied in order to identify positive combinations of the production parameters of amikacin sulphate spray-dried powders for inhalation, with the intent to expand the experimental space defined in a previous half-fractional factorial design. Three factors, namely drying temperature, feed rate and ethanol proportion, have been selected out of the initial five. In addition, the levels of these factors were increased from two to three and their effect on amikacin respirability was evaluated. In particular, focus was given on the role of ethanol presence on the formation of the microparticles for inhalation.The overall outcome of the CCD was that amikacin respirability was not substantially improved, as the optimum region coincided with areas already explored with the fractional factorial design. However, expanding the design space towards smaller ethanol levels, including its complete absence, revealed the crucial role of this solvent on the morphology of the produced particles. Peclet number and drug solubility in the spraying solution helped to understand the formation mechanism of these amikacin sulphate spray-dried particles.