Use Of Fractional Factorial Design Research Articles

The use of fractional factorial design to analyze the effect of sulfuric acid concentration and temperature on furfural yield

The use of fractional factorial design to analyze the effect of sulfuric acid concentration and temperature on furfural yield

Determination of Effective Parameters of Gas Injection in Naturally Fractured Reservoirs by Combination of Reservoir Simulation and Design of Experiment Techniques

Screening analysis is a useful guideline which helps us with proper field selection for different enhanced oil recovery processes. In this work, reservoir simulation is combined with experimental design to estimate main effects and possible interactions of reservoir rock and fluid properties on performance of different gas injection processes in naturally fractured reservoirs (NFRs). Studied parameters include reservoir thickness (h), oil viscosity μo), pore size distribution (λ), horizontal permeability (Kh), storage capacity (ω), reservoir dip, critical water saturation (Swc) and threshold capillary pressure (pct). The recovery factors of different simulation designs are analyzed by use of fractional factorial design (FFD) approach. Finally, the statistical significance of results are evaluated by hypothesis testing and ANOVA, and presented by Pareto and tornado plots. Main effect analysis showed that effective parameters are ordered with respect to their importance as follows: For Methane and nitrogen injection: Kh, dip, Swc, ω, h, μo and λ; threshold capillary pressure showed a minor effect on recovery factor. For Carbon dioxide injection: μo, dip, Swc, ω, h and Kh; Pore size distribution (λ) and threshold pressure were not shown to be statistically significant in this process. Likeness of main effects and parameter interactions for methane and nitrogen injection prove the similarity of dominant mechanisms and characteristics of these processes compared to CO2 injection which seems almost different.

The Use of Fractional Factorial Design for Atrium Fires Prediction

In order to mitigate the excessive computational cost of atrium fire simulations, a novel methodology based on the use of the Fractional Factorial Design technique to obtain an experimental validated tool, in the form of a surface response model, capable to predict fire induced conditions is proposed. This methodology is supported by results from a Design of Experiments benchmark, which consists of a set of FDS simulations in the present work. Specifically, a $$2^{6-2}_{IV}$$ approach has been considered and applied to a 20 m cubic atrium. Thus, six factors have been considered, namely the fire Heat Release Rate (HRR) and location, the exhaust flow rate, the exhaust location and activation time, and the inlet vents area. Furthermore, the smoke temperature at the roof and 15 m high and the smoke layer height have been considered the variables of interest. Subsequently, a multiple linear regression analysis has been performed to predict and compare the steady and non-steady temperature profiles and the smoke layer drop with six novel full-scale atrium fire tests, and also with specific adjusted FDS models. In addition, this methodology has been extended successfully to predict the non-steady behaviour of the fire tests. At the steady state, the HRR and the exhaust flow rate have been found to be the most relevant factors. The results obtained with the proposed methodology show a good fit both with the fire tests and with the adjusted FDS models, with discrepancies mostly below 14%. For non-steady conditions, a time analysis of the influence of the six factors has been carried out. Again, remarkable good agreement with the time-dependent experimental results is achieved, with average discrepancies below 12%, being the larger differences found in the prediction of local effects, such as the smoke ceiling jet, for high HRR or when the make-up air influence is significant. The results turn this methodology into a powerful and useful tool for fire safety designs.

Blocked semifoldovers of two-level orthogonal designs

Follow-up experimentation is often necessary to the successful use of fractional factorial designs. When some effects are believed to be significant but cannot be estimated using an initial design, adding another fraction is often recommended. As the initial design and its foldover (or semifoldover) are usually conducted at different stages, it may be desirable to include a block factor. In this article, we study the blocking effect of such a factor on foldover and semifoldover designs. We consider two general cases for the initial designs, which can be either unblocked or blocked designs. In both cases, we explore the relationships between semifoldover of a design and its corresponding foldover design. More specifically, we obtain some theoretical results on when a semifoldover design can estimate the same two-factor interactions or main effects as the corresponding foldover. These results can be important for those who want to take advantage of the run size savings of a semifoldover without sacrificing the ability to estimate important effects.

Use of fractional factorial design to study the compatibility of viral ribonucleoprotein gene segments of human H7N9 virus and circulating human influenza subtypes.

Avian H7N9 influenza viruses may pose a further threat to humans by reassortment with human viruses, which could lead to generation of novel reassortants with enhanced polymerase activity. We previously established a novel statistical approach to study the polymerase activity of reassorted vRNPs (Influenza Other Respir Viruses. 2013;7:969-78). Here, we report the use of this method to study recombinant vRNPs with subunits derived from human H1N1, H3N2, and H7N9 viruses. Our results demonstrate that some reassortant vRNPs with subunits derived from the H7N9 and other human viruses can have much higher polymerase activities than the wild-type levels.

Use of fractional factorial design for flash gap with wall lands in closed die forging

In order to improve the severe service conditions and balance the needs between the better cavity filling and longer die life of traditional closed die forgings, a new flash land named by resistance wall, which integrated the advantages of closed and open die, was introduced into knuckle hot extrusion dies. The fractional factorial design, , was employed to evaluate main effects of the structural parameters on the cavity filling, the maximum forming load and wear depth in bar fillet area, which was simulated by finite element method. Effects of six experimental factors: wall height, clearance, inclination, root fillet, flash thickness and bridge width were studied and optimised. Based on the results, a sort table about main effects was obtained and validated by production trials.

Quality assessment of total parenteral nutrition admixtures by the use of fractional factorial design

Parenteral nutrition as a specific as pect of providing nutritients still remains a permanent topic of both theoretical and experimental research. Total parenteral nutrition (TPN) admixtures have complex con tents making difficult to maintain their stability. The most critical parameter is the diameter of a lipid droplet, i.e. droplet size distribution. It is recommended that droplet size should not be more than 5 microm and that the presence of greater droplets should not exceede the value of 0.05%. Lipid droplets size is affected particularly by electrolyte addition, especially polyvalent cations. There is a danger of the added electrolytes interaction with lipid droplets which leads to their aggregation and negative effects upon the admixtures stability. The aim of this study was to as sess the effect of added electrolyte and lipid phase quan tity on the admixture stability. Electrolytes were added to the studied admixture of a defined basic formulation contents in accordance with recommenda tions from the literature. Droplets size measurements were performed using the method of laser diffraction with a laser particles analyzer. Effects of independent variables were calculated and evaluated using commercial software. Na(+), K(+), Ca(2+) and Mg(2+) concentrations, as well as the quantity of fat phase were chosen as studied fac tors, i.e. independed variables. The system response, or dependent variable was the median of droplets size. Each of the factors was varied at two levels, higher (+1) and lower (-1), according to the 2(5-2) fractional factorial design. The study suggested the presence of relative uni formity of the results of all the measurements regardless of the quantity of added electrolytes and lipid phase. It was shown that undoubtedly there is the influence of 2 valent cations (calcium and magnesium) upon lipid drop lets size, which is in a direct correlation with theoretical assumption. Within a 72-hour testing period there was no significant increase in droplet size, i.e. the studied admixtures remained stable considering droplet size median as the criterion of stability.

Use of Fractional Factorial Designs in Antiviral Drug Studies

Experimental design and analysis is an effective and commonly used tool in scientific investigations and industrial applications. Many successful applications have been reported in engineering domains, such as chemical engineering, electrical engineering, and mechanical engineering. However, few cases have been reported in biological research, particularly in virology study. Antiviral drug combinations are increasingly used to reduce possible drug‐resistant viral mutant and reduce cytotoxicity. Drug combinations have often been reported to have higher efficacy and lower individual drug dosage. However, the combined antiviral drug effect is generally hard to assess. One important reason is due to the complex interactions between biological systems and drug molecules. We report a study using fractional factorial designs to investigate a biological system with Herpes simplex virus type 1 and five antiviral drugs. The experiment uses a novel composite design that consists of a 16‐run fractional factorial design and an 18‐run orthogonal array. The results indicate that two chemical drugs, Ribavirin and Acyclovir, are more effective than three Interferon drugs. Furthermore, significant interactions exist within the Interferon drug group and within the Ribavirin‐Acyclovir chemical drug group, but the interactions between the Interferon group and the chemical group are not significant. These observations have major implications in the understanding of antiviral drug mechanism towards better design of combinatorial antiviral drug therapy. Copyright © 2012 John Wiley & Sons, Ltd.

Monitoring risk response actions for effective project risk management

AbstractComplex projects typically involve high‐consequence, project‐specific risks that require detailed analysis and for which risk response actions (RRAs) need to be developed and implemented. The risk picture is dynamic. The sources and consequences of risks evolve and change over the project lifecycle; thus, it is necessary to constantly monitor risk. RRAs that do not keep pace with the changing project situation are a major cause of risk management failures. This paper extends traditional cost risk analysis from a purely macroscopic perspective by evaluating and tracking project‐specific risks and RRAs at the microscopic level. The key elements of the method are (i) develop risk scenarios, (ii) model them using generalized decision trees, and (iii) quantify the risks using Monte Carlo simulation. For each risk the probability and cost values are conditional on the specific RRA and the preceding outcomes. The use of fractional factorial design provides a subset of all possible RRA combinations for efficiently determining the preferred total project RRA solution. Risk curves are generated to provide the necessary information to analyze, track, and manage the performance of the selected RRAs over time. Project managers and team leaders can use this information to dynamically manage the RRAs to keep pace with the changing project situation, thereby increasing the probability of project success in a cost‐effective manner. The approach is detailed using a realistic but simplified case of a project examined first with one and then expanded to three technical risks. © 2009 Wiley Periodicals, Inc. Syst Eng 13

Optimal Foldovers and Semifolding for Minimum Aberration Even Fractional Factorial Designs

Sequential experimentation is one key to the successful use of fractional factorial designs. When one fractional factorial experiment with many factors produces results that, while useful, are not quite conclusive, adding another fraction is often recommended. This article addresses adding another fraction to a resolution IV design containing near the maximal number of factors. We extend the existing literature on foldover designs by presenting general results for identifying the best foldover for resolution IV designs for k factors in n = 2k runs and minimum aberration projections of these designs. We also consider semifolding because follow-up designs with n/2 runs exist that permit estimation of just as many effects of interest as are provided by a regular foldover. The ideas are illustrated for a 15-factor ceramic fiber composite experiment.

Screening Experiments and the Use of Fractional Factorial Designs in Behavioral Intervention Research

Health behavior intervention studies have focused primarily on comparing new programs and existing programs via randomized controlled trials. However, numbers of possible components (factors) are increasing dramatically as a result of developments in science and technology (e.g., Web-based surveys). These changes dictate the need for alternative methods that can screen and quickly identify a large set of potentially important treatment components. We have developed and implemented a multiphase experimentation strategy for accomplishing this goal. We describe the screening phase of this strategy and the use of fractional factorial designs (FFDs) in studying several components economically. We then use 2 ongoing behavioral intervention projects to illustrate the usefulness of FFDs. FFDs should be supplemented with follow-up experiments in the refining phase so any critical assumptions about interactions can be verified.

Rational development of serum-free medium for Chinese hamster ovary cells

Recombinant Chinese hamster ovary (CHO) cells which produce macrophage colony-stimulating factor (M-CSF) were used as a model to systematically develop the serum-free medium. Pre-weaning strategy combined with experimental design was adopted to develop the serum-free medium for CHO cells in this study. First, CHO cells were adapted to grow in a commercial serum-free medium. Then, these weaned cells were adopted to develop our own serum-free medium using experimental design. Insulin and SerEx had significantly stimulatory influence on M-CSF production ( P < 0.05) among the seven screened supplements by use of fractional factorial design. Response surface methodology was consequently applied to find optimal concentrations of insulin and SerEx for M-CSF production. By virtue of the pre-weaning strategy and experimental designs, the development of serum-free medium could be simplified and accelerated.

Use of fractional factorial design for optimization of digestion procedures followed by multi-element determination of essential and non-essential elements in nuts using ICP-OES technique

Two digestion procedures have been tested on nut samples for application in the determination of essential (Cr, Cu, Fe, Mg, Mn, Zn) and non-essential (Al, Ba, Cd, Pb) elements by inductively coupled plasma-optical emission spectrometry (ICP-OES). These included wet digestions with HNO 3/H 2SO 4 and HNO 3/H 2SO 4/H 2O 2. The later one is recommended for better analytes recoveries (relative error < 11%). Two calibrations (aqueous standard and standard addition) procedures were studied and proved that standard addition was preferable for all analytes. Experimental designs for seven factors (HNO 3, H 2SO 4 and H 2O 2 volumes, digestion time, pre-digestion time, temperature of the hot plate and sample weight) were used for optimization of sample digestion procedures. For this purpose Plackett–Burman fractional factorial design, which involve eight experiments was adopted. The factors HNO 3 and H 2O 2 volume, and the digestion time were found to be the most important parameters. The instrumental conditions were also optimized (using peanut matrix rather than aqueous standard solutions) considering radio-frequency (rf) incident power, nebulizer argon gas flow rate and sample uptake flow rate. The analytical performance, such as limits of detection (LOD < 0.74 μg g −1), precision of the overall procedures (relative standard deviation between 2.0 and 8.2%) and accuracy (relative errors between 0.4 and 11%) were assessed statistically to evaluate the developed analytical procedures. The good agreement between measured and certified values for all analytes (relative error <11%) with respect to IAEA-331 (spinach leaves) and IAEA-359 (cabbage) indicates that the developed analytical method is well suited for further studies on the fate of major elements in nuts and possibly similar matrices.

Influence of structural variability upon sound perception: Usefulness of fractional factorial designs

The present paper introduces an efficient and time-saving approach for the evaluation of the consequences of structural uncertainties on sound perception. Its aim is to validate the use of fractional factorial designs for perceptual assessment of a model system. A test bench was used, which allowed to accurately control the variability of several structural design parameters. Sounds emitted by the bench were recorded with a dummy head and submitted to listeners during two experiments, in which they had to evaluate the dissimilarity of each sound to a reference, representing the nominal state of the device. In the first experiment, six factors, assumed to be independent, were used to define a fractional factorial design. As an analysis of variance showed that two interactions between factors should have been taken into account, a second experimental design was developed to quantify these interactions. These two experiments allowed to define an accurate model of sound perception, describing the effect of each factor on the perceived dissimilarity. Thus, it was possible to relate the variability of the structure to the perception of the sound emitted with few experimental effort.

Use of fractional factorial design for selection of nutrients for culturing Paecilomyces variotii in eucalyptus hemicellulosic hydrolysate

A eucalyptus hemicellulose fraction was hydrolysed by treating eucalyptus wood chips with sulfuric acid. The hydrolysate was used as the substrate to grow Paecilomyces variotii IOC-3764 cultured for 72 or 96 hours. The influence of the inhibitors, nutrients and fermentation time was verified by a 28-4 and, subsequently, a 25-1 fractional factorial design. The effects of the inhibitors (acetic acid and furfural), nutrients (rice bran, urea, potassium nitrate, ammonium sulfate, magnesium sulfate and sodium phosphate) and fermentation time were investigated. The highest yield (10.59 g/L of biomass) was obtained when the microorganisms were cultivated for 72 hours in a medium composed of 30 g/L rice bran, 9.4 g/L ammonium sulfate (2 g/L nitrogen) and 2 g/L sodium phosphate.

Use of Fractional Factorial Design in the Development of a Method to Measure the Delamination of Unsaturated Polyester Resin Laminates

The development of a method for the measurement of delamination in unsaturated polyester resin laminates is described. A laminate is wedge-opened in a tensile testing machine, and the load at break is taken as a measurement for delamination. The results are compared with the delamination measured by the degree of fibre pull-out on the surface of laminates opened by hand. By testing a large sample series with both methods it could be shown by statistical analysis that wedge-opening in a tensile testing machine is more sensitive towards differences in laminate properties, and therefore gives more reliable results.

Use of Fractional Factorial Design in the Development of a Method to Measure the Delamination of Unsaturated Polyester Resin Laminates

The development of a method for the measurement of delamination in unsaturated polyester resin laminates is described. A laminate is wedge-opened in a tensile testing machine, and the load at break is taken as a measurement for delamination. The results are compared with the delamination measured by the degree of fibre pull-out on the surface of laminates opened by hand. By testing a large sample series with both methods it could be shown by statistical analysis that wedge-opening in a tensile testing machine is more sensitive towards differences in laminate properties, and therefore gives more reliable results.

An explanation and critique of taguchi's contributions to quality engineering

AbstractRecently there has been much interest and some controversy concerning the statistical methods employed by Professor Genichi Taguchi of Japan for improving the quality of products and processes. These methods include the use of fractional factorial designs and other orthogonal arrays, parameter design to minimize sensitivity to environmental factors, parameter design for minimizing transmitted variation, signal‐to‐noise ratios, loss functions, accumulation analysis, minute analysis and the analysis of life test data. This paper explains some of Taguchi's contributions to quality engineering and also provides a critical evaluation of his statistical methods. Our conclusion is that although on the one hand, Professor Taguchi's quality engineering ideas are of great importance and should become part of the working knowledge of every engineer, on the other hand, many of the techniques of statistical design and analysis he employs to put these ideas into practice are often inefficient and unnecessarily complicated and should be replaced or appropriately modified. In this short article only an overview is attempted, but references are appended where these matters are discussed in greater detail.