Methodology of factorial design deriving guidelines for simulation of growth curve and production of sugars by Spirulina (Arthrospira) maxima

It is practical, economic and sometimes essential to derive rules or conclusions by performing lesser runs of experiments. In this part, a methodology based on 2 f factorial design was brought up to derive guidelines to simulate growth curve and production of sugars by Spirulina (Arthrospira) maxima . The growth curve or accumulation process of sugars was idealized by sets of straight lines limited by phase transfers of growth or accumulation of sugars. Normal analyses of the critical values of the transfers were used to derive their linear relationships with the initial conditions of the experimental factors. These linear functions were called guidelines and were used to simulate the growth curve or accumulation of sugars. Generalization of the guideline technique was determined by the kinetic limitation of nutrient nitrogen or sulfur that was dependent upon their stoichiometric deficiency directly derived from their initial values in the medium. This method uses the initial conditions of culture and does not need measurements of concentrations of nitrate, sulfate and pigments during cultivation. It is a practical and useful alternative way to trace and predict approximately the growth curve and production of sugars by S. maxima .

Modeling of biodiesel production: Performance comparison of Box–Behnken, face central composite and full factorial design

The performances of the response surface methodology(RSM)in connection with the Box–Behnken,face central composite or full factorial design(BBD,FCCD or FFD,respectively)were compared for the use in modeling of the NaOH-catalyzed sunflower oil ethanolysis.The influence of temperature,catalyst loading,and ethanol-to-oil molar ratio(EOMR)on fatty acid ethyl esters(FAEE)content was evaluated.All three multivariate strategies were efficient in the statistical modeling and optimization of the influential process variables but BBD and FCCD realization involved less number of experiments,generating smaller costs,requiring less work and consuming shorter time than the corresponding FFD.All three designs resulted in the same optimal catalyst loading(1.25%of oil)and EOMR(12:1).The reduced two-factorinteraction(2 FI)models based on the BBD and FCCD defined a range of optimal reaction temperature(25℃–75℃)and 25℃,respectively while the same model based on the 33 FFD appointed 75℃.The predicted FAEE content of about 97%–98.0%was close to the experimentally obtained FAEE content of about 97.0%–97.6%under the optimal reaction conditions.Therefore,the simpler BBD or FCCD might successfully be applied for statistical modeling of biodiesel production processes instead of the more extensive,more laborious and more expensive FFD.

Factorial Experimental Design to Study the Effects of Layers and Fiber Content on Concrete Flexural Behavior

Experimentation has come a long in helping researchers achieve breakthroughs in their different scientific areas and engineering happens to be one of those areas with the most impact from experimental advancement. The need for valid experimental results free from biases and confounding conclusions has prompted the development of new experimental techniques that takes consideration of all applicable factor and combinations in providing answers on a research topic, and the Factorial Experimental design credited to Sir Ronald Fisher is one technique yielding highly valid results. This paper uses the factorial design of experiments to research the flexural impact of polyvinyl acetate fiber and layered concrete in construction. The experiment considered two levels of fiber contents and two levels of layers, and prepared samples with all combinations of the variable factors. The samples were tested after 7 days from casting for flexural strength and an advance statistical analysis was performed on the flexural responses of the samples using R-program. The results from the analyses revealed the significance of the variables to the flexural strength of the samples, as well as their interactions. The experiment concluded that based on the number of layers and fiber content used for the experiment, casting concrete in layers does have a significant negative effect on the flexural strength of concrete, and the failure pattern of concrete members under flexural load in evidently influenced by the material composition of the concrete, and that it can be evidently influenced by casting the concrete in layers.

Construction of Split-Plot Designs with General Minimum Lower Order Confounding

Fractional factorial split-plot design has been widely used in many fields due to its advantage of saving experimental cost. The general minimum lower order confounding criterion is usually used as one of the attractive design criterion for selecting fractional factorial split-plot design. In this paper, we are interested in the theoretical construction methods of the optimal fractional factorial split-plot designs under the general minimum lower order confounding criterion. We present the theoretical construction methods of optimal fractional factorial split-plot designs under general minimum lower order confounding criterion under several conditions.

Modeling Experimental Design for Photo-Fenton Degradation of Methomyl

Modeling experimental design was used to study the main effects and the interaction effects between operational parameters in the photocatalytic degradation of pesticide methomyl. The important parameters which affect the removal efficiency of methomyl such as concentration of Fe(NO3)3, concentration of H2O2, initial concentration of the pesticide and pH. The parameters were coded as x1, x2, x3 and x4, consecutively, and were investigated at two levels (–1 and +1). The effects of individual variables and their interaction effects for dependent variables, namely, photocatalytic degradation efficiency (%) were determined. From the statistical analysis, the most effective parameters in the photocatalytic degradation efficiency were initial concentrations of the methomyl and Fe(NO3)3. The interaction between initial concentration of the pesticide and Fe(NO3)3 was the most influencing interaction. The optimum conditions that were obtained for the photocatalytic degradation of methomyl were: minimum quantity of contaminant: 6 × 10–5 mol.L–1, maximum quantity of Fe(NO3)3: 5 × 10–4 mol.L-1, initial pH of the solution: 3 and maximum quantity H2O2: 10–2 mol.L–1.

Design and Robust Performance Evaluation of a Fractional Order PID Controller Applied to a DC Motor

This paper proposes a methodology for the quantitative robustness evaluation of PID controllers employed in a DC motor. The robustness analysis is performed employing a 2~3 factorial experimental design for a fractional order proportional integral and derivative controller(FOPID), integer order proportional integral and derivative controller(IOPID)and the Skogestad internal model control controller(SIMC). The factors assumed in experiment are the presence of random noise,external disturbances in the system input and variable load. As output variables, the experimental design employs the system step response and the controller action. Practical implementation of FOPID and IOPID controllers uses the MATLAB stateflow toolbox and a NI data acquisition system. Results of the robustness analysis show that the FOPID controller has a better performance and robust stability against the experiment factors.

From Factory Floor to Design Headquarters

AN iPhone made by a Chinese OEM (original equipment manufacturer) sells for US$499 in the US market, while the commissioned Chinese manufacturer of the phone gets a recompense of only US $4.

Kinetics of phenol and m-cresol biodegradation by an indigenous mixed microbial culture isolated from a sewage treatment plant

An acclimatized mixed microbial culture,predominantly Pseudomonas sp.,was enriched from a sewage treatment plant,and its potential to simultaneously degrade mixtures of phenol and m-cresol was investigated during its growth in batch shake flasks.A 22 full factorial design with the two substrates at two different levels and different initial concentration ranges(low and high),was employed to carry out the biodegradation experiments.The substrates phenol and m-cresol were completely utilized within 21 h when present at low concentrations of 100 mg/L for each,and at high concentration of 600 mg/L for each,a maximum time of 187 h was observed for their removal.The biodegradation results also showed that the presence of phenol in low concentration range(100–300 mg/L) did not inhibit m-cresol biodegradation.Whereas the presence of m-cresol inhibited phenol biodegradation by the culture.Moreover, irrespective of the concentrations used,phenol was degraded preferentially and earlier than m-cresol.A sum kinetics model was used to describe the variation in the substrate specific degradation rates,which gave a high coeffcient of determination value(R2>0.98)at the low concentration range of the substrates.From the estimated interaction parameter values obtained from this model,the inhibitory effect of phenol on m-cresol degradation by the culture was found to be more pronounced compared to that of m-cresol on phenol.This study showed a good potential of the indigenous mixed culture in degrading mixed substrate of phenolics.

A new rotation method for constructing orthogonal Latin hypercube designs

Latin hypercube designs(LHDs)are very popular in designing computer experiments.In addition,orthogonality is a desirable property for LHDs,as it allows the estimates of the main effects in linear models to be uncorrelated with each other,and is a stepping stone to the space-filling property for fitting Gaussian process models.Among the available methods for constructing orthogonal Latin hypercube designs(OLHDs),the rotation method is particularly attractive due to its theoretical elegance as well as its contribution to spacefilling properties in low-dimensional projections.This paper proposes a new rotation method for constructing OLHDs and nearly OLHDs with flexible run sizes that cannot be obtained by existing methods.Furthermore,the resulting OLHDs are improved in terms of the maximin distance criterion and the alias matrices and a new kind of orthogonal designs are constructed.Theoretical properties as well as construction algorithms are provided.

Theory of optimal blocking for fractional factorial split-plot designs

The issue of optimal blocking for fractional factorial split-plot (FFSP) designs is considered under the two criteria of minimum aberration and maximum estimation capacity. The criteria of minimum secondary aberration (MSA) and maximum secondary estimation capacity (MSEC) are developed for discriminating among rival nonisomorphic blcoked FFSP designs. A general rule for identifying MSA or MSEC blocked FFSP designs through their blocked consulting designs is established.

Monitoring Flue-Cured Tobacco Leaf Chlorophyll Content under Different Light Qualities by Hyperspectral Reflectance

Rapid assessment of foliar chlorophyll content in tobacco is critical for assessment of growth and precise management to improve quality and yield while minimizing adverse environmental impact. Our objective is to develop a precise agricultural practice predicting tobacco-leaf chlorophyll-a content. Reflectance experiments have been conducted on flue-cured tobacco over 3 consecutive years under different light quality. Leaf hyperspectral reflectance and chlorophyll-a content data have been collected at 15-day intervals from 30 days after transplant until harvesting. We identified the central band that is sensitive to tobacco-leaf chlorophyll-a content and the optimum wavelength combinations for establishing new spectral indices (simple ratio index, RVI;normalized difference vegetation index, NDVI;and simple difference vegetation index, DVI). We then established linear and BackPropagation (BP) neural network models to estimate chlorophyll-a content. The central bands for leaf chlorophyll-a content are concentrated in the visible range (410 - 680 nm) in combination with the shortwave infrared range (1900 - 2400 nm). The optimum spectral range for the spectral band combinations RVI, NDVI, and DVI are 440 and 470 nm, 440 and 470 nm, and 440 and 460 nm, respectively. The linear RVI, NDVI, and DVI models, SMLR model and the BP neural network model have respective R2 values of 0.76, 0.77, 0.69, 0.78 and 0.86, and root mean square error values of 0.63, 1.60, 1.59, 2.04 and 0.05 mg chlorophyll-a/g (fresh weight), respectively. Our results identified chlorophyll-a sensitive spectral regions and new indices facilitate a rapid, non-destructive field estimation of leaf chlorophyll-a content for tobacco.

In silico cell factory design driven by comprehensive genome‑scale metabolic models:development and challenges

Genome-scale metabolic models(GEMs)have been widely used to design cell factories in silico.However,initial flux balance analysis only considers stoichiometry and reaction direction constraints,so it cannot accurately describe the distribution of metabolic flux under the control of various regulatory mechanisms.In the recent years,by introducing enzymology,thermodynamics,and other multiomics-based constraints into GEMs,the metabolic state of cells under different conditions was more accurately simulated and a series of algorithms have been presented for microbial phenotypic analysis.Herein,the development of multiconstrained GEMs was reviewed by taking the constraints of enzyme kinetics,thermodynamics,and transcriptional regulatory mechanisms as examples.This review focused on introducing and summarizing GEMs application tools and cases in cell factory design.The challenges and prospects of GEMs development were also discussed.

Optimized polymer flooding projects via combination of experimental design and reservoir simulation

The conventional approach for an EOR process is to compare the reservoir properties with those of successful worldwide projects.However,some proper cases may be neglected due to the lack of reliable data.A combination of experimental design and reservoir simulation is an alternative approach.In this work,the fractional factorial design suggests some numerical experiments which their results are analyzed by statistical inference.After determination of the main effects and interactions,the most important parameters of polymer flooding are studied by ANOVA method and Pareto and Tornado charts.Analysis of main effects shows that the oil viscosity,connate water saturation and the horizontal permeability are the 3 deciding factors in oil production.The proposed methodology can help to select the good candidate reservoirs for polymer flooding.

Selecting baseline designs using a minimum aberration criterion when some two-factor interactions are important

This article considers the problem of selecting two-level designs under the baseline parameterisation when some two-factor interactions are important.We propose a minimum aberration criterion,which minimises the bias caused by the non-negligible effects.Using this criterion,a class of optimal designs can be further distinguished from one another,and we present an algorithm to find the minimum aberration designs among the D-optimal designs.Sixteen-run and twenty-run designs are summarised for practical use.

Funnel testing in webpage optimisation:representation,design and analysis

When optimizingwebpages in order to achieve the best conversion rate,the traditional approach is to isolate and analyze themseparately through a sequence of experiments.In thispaper,wepropose a new framework to study a systemofwebpages simultaneously through the use of directed graph,fractional factorial design and simple optimization algorithm.The illustrative example shows that such complicated web systems can be easily studied and optimized by using the proposed methodology.

Experimental investigation and prediction of tribological behavior of unidirectional short castor oil fiber reinforced epoxy composites

The present study aims at introducing a newly developed natural fiber called castor oil fiber,termed ricinus communis,as a possible reinforcement in tribo-composites.Unidirectional short castor oil fiber reinforced epoxy resin composites of different fiber lengths with 40%volume fraction were fabricated using hand layup technique.Dry sliding wear tests were performed on a pin-on-disc tribometer based on full factorial design of experiments(DoE)at four fiber lengths(5,10,15,and 20 mm),three normal loads(15,30,and 45 N),and three sliding distances(1,000,2,000,and 3,000 m).The effect of individual parameters on the amount of wear,interfacial temperature,and coefficient of friction was studied using analysis of variance(ANOVA).The composite with 5 mm fiber length provided the best tribological properties than 10,15,and 20 mm fiber length composites.The worn surfaces were analyzed under scanning electron microscope.Also,the tribological behavior of the composites was predicted using regression,artificial neural network(ANN)-single hidden layer,and ANN-multi hidden layer models.The confirmatory test results show the reliability of predicted models.ANN with multi hidden layers are found to predict the tribological performance accurately and then followed by ANN with single hidden layer and regression model.

Investigation of influential factors on the tensile strength of cold recycled mixture with bitumen emulsion due to moisture conditioning

The present study attempts to investigate the effect of moisture conditioning on the indirect tensile strength(ITS) of cold recycled mixture with bitumen emulsion.Firstly,samples were prepared using a Superpave gyratory compactor.They were hence conditioned using moisture induced sensitivity tester(MIST) device.Factorial design was carried out considering four factors each at two different levels.These factors were specimen thickness,air voids content,pressure and number of cycles.In the MIST device,samples are cyclically subjected to water pressure through the sample pores.The MIST conditioned samples were tested for indirect tensile strength.The analysis of two-level full-factorial designed experiments revealed that all four factors have a negative effect on tensile strength of cold recycled mixture with bitumen emulsion.Specimen thickness was the most significant factor affecting the tensile strength followed by air voids content.In twofactor interaction,specimen thickness-number of cycles,air voids content-pressure,and pressure-number of cycles were significant.The most significant three-factor interaction was specimen thickness-pressure-number of cycles.The results from the study suggest that in measuring tensile strength,the appropriate specimen thickness and air voids content should be selected to quantify the representative tensile strength for in-situ conditions.

Removal of antibiotics in a parallel-plate thin-film-photocatalytic reactor: Process modeling and evolution of transformation by-products and toxicity

Photocatalytic degradation of sulfamethoxazole(SMX) antibiotic has been studied under recycling batch and homogeneous flow conditions in a thin-film coated immobilized system namely parallel-plate(PPL) reactor. Experimentally designed, statistically evaluated with a factorial design(FD) approach with intent to provide a mathematical model takes into account the parameters influencing process performance. Initial antibiotic concentration, UV energy level, irradiated surface area, water matrix(ultrapure and secondary treated wastewater) and time, were defined as model parameters. A full of 2~5 experimental design was consisted of 32 random experiments. PPL reactor test experiments were carried out in order to set boundary levels for hydraulic, volumetric and defined defined process parameters. TTIP based thin-film with polyethylene glycol + TiO_2 additives were fabricated according to pre-described methodology. Antibiotic degradation was monitored by High Performance Liquid Chromatography analysis while the degradation products were specified by LC–TOF-MS analysis. Acute toxicity of untreated and treated SMX solutions was tested by standard Daphnia magna method. Based on the obtained mathematical model, the response of the immobilized PC system is described with a polynomial equation. The statistically significant positive effects are initial SMX concentration,process time and the combined effect of both, while combined effect of water matrix and irradiated surface area displays an adverse effect on the rate of antibiotic degradation by photocatalytic oxidation. Process efficiency and the validity of the acquired mathematical model was also verified for levofloxacin and cefaclor antibiotics. Immobilized PC degradation in PPL reactor configuration was found capable of providing reduced effluent toxicity by simultaneous degradation of SMX parent compound and TBPs.

The correlation between friction coefficient and areal topography parameters for AISI 304 steel sliding against AISI 52100 steel

Dry wear experiments provide an insight detail on how severely contacting surfaces change under unlubricated sliding condition. The theory of dry sliding wear is used for understanding mixed-lubrication regime in which asperity interactions play a significant role in controlling of the friction coefficient(f). The purpose of this work is to study the tribological behavior of AISI 304 steel in contact with AISI 52100 steel during wear. Both materials are used in rolling element bearings commanly. Experiments are carried out using a pin-on-disc tribometer under dry friction condition. The areal(three dimensional, 3D) topography parameters are measured using a 3D white light interferometer(WLI) with a 10× objective. After wear tests, wear mechanisms are analyzed utilizing scanning electron microscope(SEM). Factorial design with custom response surface design(C-RSD) is used to study the mutual effect of load and speed on response variables such as f and topography parameters. It is observed that the root mean square roughness(S_(q)) decreases with an increase in sliding time. Within the range of sliding time, S_(q) decreases with an increase in the normal load. Within the range of sliding speed and normal load, it is found that S_(q), mean summit curvature(S_(sc)), and root mean square slope(S_(dq)) are positively correlated with f. Whereas, negative correlation is found between f and correlation length(Sal), mean summit radius(R), and core roughness depth(S_(k)).

Enzyme hydrolyzed bael fruit liquefaction and its kinetic study

The study aims to explore the mechanism and optimize the process of enzyme hydrolyzed bael fruit(Aegle marmelos)liquefaction using two different enzymes:pectinase and macerozyme r-10(enzyme mixture).A full factorial design was applied for the factors with 0.05–1.5%(w/w)enzyme concentration(EC),30–60℃ temperature,and incubation time of 30–240 min for pectinase and 60–360 min for macerozyme.Quadratic polynomial models were developed,showing R^(2)≥0.94.Multi-objective numeric optimization was followed to maximize the increase in yield,total reducing sugar(TRS),clarity,and minimizing EC,temperature and time.Enzyme-treated juice extracts were acceptable on the sensory scale with overall acceptability>5.Maximum pomace reduction of 58.8%and 78.9%along with rise in mono and disaccharides were observed after treating with pectinase(t=240 min)and macerozyme(t=360 min),respectively at identical 0.775%EC and 45℃ temperature.With the pectinase enzyme,an optimumΔyield of 32.4%was obtained at 0.82%EC,43℃ temperature in 169.4 min.Subsequently,with the macerozyme,an optimumΔyield of 39.6%was attained at 0.96%EC,45.6°C temperature in 245.9 min.Substrate degradation in bael fruit by enzymatic hydrolysis with pectinase(EC=0.01–1.50%,time=2.5–240 min)and macerozyme(EC:0.01–1.50%,time:5–360 min)was studied at their respective optimum temperatures.The modified Michaelis-Menten showed a good fit(R 2>0.98)with the non-linear curve fitting method.Macerozyme treatment showed slower enzyme activity with higher substrate degradation but lower nutrient content compared to the pectinase treatment.