Statistical Design of Experiment (DoE) Research Papers (original) (raw)

Visando instigar e motivar alunos de cursos de engenharia, este estudo busca, através da aplicação do método Aprendizado Baseado em Problemas, propiciar situações desafiadoras e criativas para resolução de problemas. A atividade didática proposta aos estudantes utiliza Projeto de Experimentos (DoE) para avaliar o movimento de esferas de diferentes materiais e dimensões através de fluidos com densidades distintas. Os resultados mostraram correlações significativas entre os fatores e a variável resposta, reforçando a possibilidade de aplicação do DoE como uma ferramenta para a busca de soluções de engenharia e favorecimento do aprendizado.

- by and +2
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- Sustainable Development, Triple Bottom Line, Statistical Design of Experiment (DoE), Sustentabilidade

Context: Jordan is looking for a cheap and locally affordable source for its cosmetics, fuel and medical applications. Jojoba offers one solution to such problems. It is considered as a good medicinal plant that can be used for several applications. Aims: To evaluate the effect of parameters as mixing speed, temperature, feedstock grain size, mixture ratio and mixing time on the jojoba yield. Methods: The mathematical model combining the effect of all the above variables was then used to find the optimum combination for maximum yield. Response Surface Methodology (RSM) technique was used for modeling and optimization. Based on the Pareto chart of parameters effect, the seed size was the most significant followed with temperature effect. Results: It was found that the optimum values obtained for best yield were seed size of about 0.48 mm, the temperature of about 65°C and mixing time of 2.8 hours maximum yield of about 56% wt can be obtained. Conclusions: A mathematical model was suc...

- by Luigi Vitiello
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- Mathematics, Wind Energy, Applied Statistics, Finite element method

Product weight is a crucial aspect in the Fish Industry. In this regard, the cans whose net weight is below LSL (Lower Specification Level) may increase customer complaints and financial sanctions. On the other hand, net weights above USL (Upper Specification Limit) represent significant economic burdens for the companies associated with this sector. Therefore, this paper focuses on the application of statistical experimental design and response surface methodologies to reduce the variability in net weight of canned tuna. First, the effects of two factors: Tomato Sauce Temperature (65°C-70°C, 70°C-75°C and 75°C-80°C), Conveyor Belt Speed (135 rpm, 140 rpm, and 145 rpm) and their interactions, were assessed via applying the 3 k factorial design. Then, a response surface analysis was performed to define the optimal conditions for the canning process. Finally, a bivariate regression analysis was carried out to develop a predictive model for average standard deviation of net weight per unit. In this case, the results demonstrated that both interaction and factors were found to be statistically significant (P-value < 0.05). Additionally, it is shown that the regression model is capable of predicting the response variable with high accuracy (Q 2 = 89.89%).

In simulation-based realization of complex systems, we are forced to address the issue of computational complexity. One critical issue that must be addressed is the approximation of reality using surrogate models to replace expensive simulation models of engineering problems. In this paper, we critically review over two hundred papers. We find that a framework for selecting appropriate surrogate modeling methods for a given function with specific requirements is lacking. To address this gap, we hypothesize that a trade-off among three main drivers, namely, size (how much information is necessary to compute the surrogate model), accuracy (how accurate the surrogate model must be) and computational time (how much time is required for surrogate modeling process) is needed. In the context of the hypotheses, we review the state-of-the-art surrogate modeling literature to answer the following three questions: 1. What are the main classes of the design of experiment (DOE) methods, surrogate modeling methods and model-fitting methods based on the requirements of size, computational time, and accuracy? 2. Which surrogate modeling method is suitable based on the critical characteristics of the requirements of size, computational time and accuracy? 3. Which DOE is suitable based on the critical characteristics of the requirements of size, computational time and accuracy?
Based on these three characteristics, six different categories for the surrogate models are framed through a critical evaluation of the literature. These categories provide a framework for selecting an efficient surrogate modeling process to assist those who wish to select more appropriate surrogate modeling techniques for a given function. It is also summarized in Table 4 and Figure 3 and 5). Artificial neural networks, response surface models, and kriging are more appropriate for large problems, less computation time and high accuracy, respectively. Also, Latin Hypercube, fractional factorial designs, and D-Optimal designs are appropriate experimental designs. Our proposed framework is a qualitative evaluation and a mental model that is based on quantitative results and findings of authors in the published literature. The value of such a framework is in providing practical guidance for researchers and practitioners in the industry to choose the most appropriate surrogate model based on incomplete information about the engineering design problem. Our contribution is to use three drivers, namely, computational time, accuracy, and problem size instead of using one single measure that authors generally used in the published literature.

- by Reza Alizadeh and +1
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- Machine Learning, Engineering Design, Support Vector Machines, Statistical Design of Experiment (DoE)

This guide book is especially designed for beginners in SPSS ans have some background knowledge of Statistical techniques. For ease of students and users different renowned books which are easily available and taught in universities are used for the solution examples by using SPSS. This guide covers most of topics of Statistics till Bachelor 's level and for further guidance and understanding, our You Tube channel may be referred.

Douglas Montgomery - JMP complementary

- by John Wang
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- Statistical Design of Experiment (DoE)

An experimental design consists of a careful description of how a particular hypothesis can be experimentally tested. This requires: (a) an explicit specification of the treatment factors to be tested; (b) the specific range of values over which these treatment factors will be tested; (c) the manner in which observations will be generated, recorded, and reported; and (d) the criteria that will be used to evaluate the degree to which the observations appear to support the hypothesis or to be inconsistent with the hypothesis. Some basic concepts of design of experiment Treatments are the different procedures we want to compare. These could be different kinds or amounts of fertilizer in agronomy, different long distance rate structures in marketing, or different temperatures in a reactor vessel in chemical engineering. Experimental units are the things to which we apply the treatments. These could be plots of land receiving fertilizer, groups of customers receiving different rate structures, or batches of feedstock processing at different temperatures. Responses are outcomes that we observe after applying a treatment to an experimental unit. That is, the response is what we measure to judge what happened in the experiment; we often have more than one response. Responses for the above examples might be nitrogen content or biomass of corn plants, profit by customer group, or yield and quality of the product per ton of raw material. Randomization is the use of a known, understood probabilistic mechanism for the assignment of treatments to units. Other aspects of an experiment can also be randomized: for example, the order in which units are evaluated for their responses.

- by Abdullah Al Zabir
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- Statistical Design of Experiment (DoE)

Aquafil S.p.A. has been one of the leading players in the production of Nylon 6. Over 60% of its total production is composed by the so called solution dyed industrial yarns. The fibers are colored through a mass pigmentation process by the addition of Color Master batch during the melt spinning. From the industrial point of view, the most important problem
for the Color Master batch production is to maximize the tinting strength of the color pigment. This have to be achieved by optimizing the fillers dispersion into the polymer bulk without using the dispersing additives, that can show detrimental effect during melt spinning. The dispersion degree of the pigments is the key point of the master batch production process and
it depends on the physical properties of pigment particles, on the process parameters involved during extrusion and on the pigment concentration in color master batch. During IPSP2014, the Aquafil team of students and researchers worked on the realization of two models, one empirical and one theoretical, that could reproduce and predict the tinting strength of the Color Master batches, starting from the production process parameters. At the end of the week, the two developed models were able to qualitatively reproduce the experimental results measured on a set of Monoconcentrated Color Master batches, which were realized for this purpose by Aquafil during the event. Moreover, both models suggest that a critical production parameter for the realization of masterbatches with optimized tinting strength is the temperature profile of the extruder barrels.

- by D M S Sultan and +1
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- Statistical Design of Experiment (DoE)

You yourself, or what is the same, your experience is such ``coin'' that, while you aren't questioned, it rotates all the time in ``free flight''. And only when you answer the question the ``coin'' falls on one of the sides: ``Yes'' or... more

Design of Experiments (DOE) is statistical tool deployed in various types of system, process and product design, development and optimization. It is multipurpose tool that can be used in various situations such as design for comparisons, variable screening, transfer function identification, optimization and robust design. This paper explores historical aspects of DOE and provides state of the art of its application, guides researchers how to conceptualize, plan and conduct experiments, and how to analyze and interpret data including examples. In addition, this paper reveals that in past 20 years application of DOE have been growing rapidly in manufacturing as well as non-manufacturing industries. It was most popular tool in scientific areas of medicine, engineering, biochemistry, physics, computer science and counts about 50% of its applications compared to all other scientific areas.

Onion is densely produced crop in India. The harvesting of onion crop is laborious work and requires huge amount of manpower and time. As a part of harvesting of onion, root and shoot has to be trimmed manually, this is a labour oriented process. One of the main reasons of low productivity is low level of mechanization and less technology utilizatio n. Machine for cutting root and shoot is not available in India and imported machines are expensive and an Indian farmer cannot afford such high price. Farmers incur financial loss because of non-availability of manpower. The purpose of the work is to " des ign and develop a prototype of onion root and shoot cutting machine " that can cut the root and shoot of onion once fed into the machine. This mechanization will also reduce unit cost of production through higher productivity. The major objective of this work is to reduce total expenses and dependency on labours and to increase the net revenue at an affordable price.

- by W.N.N Wan Omar and +1
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- Applied Statistics, Statistical Design of Experiment (DoE), Optimization, RSM

The objective of this research is to study the influence of Process parameters and electrode shape configuration on the Machining characteristics of die sinking EDM. The present work aims to study the effect of different electrode shapes (Circular, rectangular and triangular) With constant cross sectional area of 280 mm2 on material removal rate (MRR), surface roughness (SR) and Electrode wear rate (EWR) for AISI P20 tool steel workpiece material and pure copper As electrode material. The optimization of the parameters of the EDM machining will be carried out by using the taguchi's method for design of experiments (DOE). The objective of the analysis is to identify the Optimum electrode shapes in terms of higher MRR, minimum EWR and excellent surface finish. The different parameters considered while carrying out the experiments on the Die-Sinking EDM will be the current applied, pulse on time and pulse off time required etc.

Electric discharge machining (EDM) is one of the widely used non-traditional machining processes especially used for producing intricate or complex geometry on difficult-to-machine materials. The surface integrity is one of the important performance attributes of EDM process. With upcoming worldwide applications of Titanium grade-2, machining has become an important issue which needs to be investigated in details. Based on the design of experiment (DOE), a well-designed experiment was conducted with L18 Orthogonal Array (OA). The present study investigates the effect of process parameters such as Peak Current (Ip), Pulse on Time (Ton), Duty Cycle (%) and Voltage Gap (volt) on performance characteristics such as surface roughness (SR). In this research work, Regression analysis was used to find out the optimal level of the parameters

- by M. Mustafaiz Ahmad and +1
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- Mechanical Engineering, Statistical Design of Experiment (DoE), ANOVA, Regression Analysis

A design of experiment (DOE) is used in many industrial sectors in the development and optimization of manufacturing processes. DOE is a more effective way to determine the impact of two or more factors on a response. In this paper, a Two-Level Fractional Factorial design was employed to develop the important factors that significantly affect new promising OT Rubber recycling machine using a DOEs analysis. Central composite design (CCD) and response surface methodology (RSM) were used to optimize the isolating screen size. The CCD considered five factors with two-level full factorial design. CCD experiments using RSM was proved to be an optimal tool for optimization.

Friction Stir Welding (FSW) was carried out on commercially available Aluminum Alloy 6063T-6 and AA 6061 plates, with dimensions of 150×75×6 mm. in my project we have selected dissimilar materials, especially on aluminum alloy 6061 and 6063-T6, Design of experiment (DOE) was applied to determine the most important factors which influence Ultimate Tensile Strength (UTS) of AA 6063 T-6 and AA 6061 joints produced by Friction Stir Welding (FSW). Effect of two factors which include tool rotational speed, welding speed. By Taguchi method using L9 orthogonal array, the optimum of process parameters was determined. GRA analysis was carried out to determine the percentage contribution of each factor on Tensile Strength. Particular emphasis has been given to the Effect of welding speed and tool rotation speed on welded work piece and study on mechanical properties.

One of the most important weld quality characteristics related to the strength of the weld is the hardness of melted zone (HMZ) that is affected by different input parameters in the submerged arc welding process. In recent years, expensive nanomaterials have been effectively used in improving the quality of products in various fields. Keeping this in mind, it was therefore, decided to use a cost-effective approach to extract expensive and poisonous vanadium, from the hazardous wastewater collected from the Bistoon thermal power plant in Kermanshah province in Iran, and then introduce it into the weld pool via the cheap boehmite nanoparticles to investigate its impact on the HMZ. A five-level five-factor rotatable central composite design was then employed for collecting data in modeling of the HMZ as a function of arc voltage (V), welding current (I), stick-out (N), welding speed (S), and thickness of boehmite nanoparticles surface adsorbed with vanadium (F) coated on low-carbon steel plates (St37) prior to actual welding. The results showed that the addition of boehmite nanoparticles surface adsorbed with vanadium increased the HMZ by 13 % approximately.

- by Pooria Naderian
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- Microstructure, Synthesis of nanoparticles, Design of Experiments, Nanomaterials

Physicochemical properties Design of experiment CO 2 solubility To study CO 2 capture potential, three types of transition-temperature mixtures (TTMs) were prepared by mixing ethyltriphenylphosphonium bromide (MTPPB) as a hydrogen bond acceptor (HBA) and n-methyl diethanolamine (MDEA) as a hydrogen bond donor (HBD) in different molar ratios (1:7, 1:10 and 1:16). Fourier transform infrared spectroscopy (FT-IR) results showed that TTMs have almost similar spectra to their HBD (MDEA) with different levels of transmittance and exhibit similar behavior. From the experimental results, it was found that the thermal stability, viscosity and surface tension of TTMs decreased as the concentration of MDEA in the mixture increased. According to response surface methodology (RSM) models and analysis of variance (ANOVA), temperature and molar ratio had a great effect on the viscosity and surface tension of TTMs. Finally, it was found that CO 2 solubility in TTMs (at 303.15 K at pressure up to 1.35 MPa) was enhanced as the MDEA quantity increased in the mixture up to 1:10 mol ratio. However, by increasing MDEA concentration to 16:1 mol ratio, there was a decreasing trend in the CO 2 solubility data. Also, all TTMs, particularly TTM containing 10:1 mol MDEA (MTPPB-MDEA 1:10) exhibited an equilibrium loading capacity approaching 1 mol CO 2 per mole solvent at high pressure, revealing their high potential for CO 2 capture. A comparison showed that the CO 2 solubility in the studied solvents was higher than that of existing deep eutectic solvents (DESs) and other TTMs as well as several ionic liquids (ILs) to date. To the best of our knowledge, this is the first study to report the CO 2 solubility in phosphonium-base TTMs containing MDEA.

This paper studies the effect of process parameters like melt temperature, mold temperature,packing
pressure, sprue diameter and gate diameter on product quality responses like fill time of cavity and
volumetric shrinkage of electrical switch board.In the first part an experimental methodology was
developed using DOE (Design of experiment)technique. Taguchi method was used to design an orthogonal
array of five factors having three levels. Second part is developing FEM simulation using MFA software
provided by Autodesk Company. Main results are based on S/N ratio and ANOVA analysis. It is found that
most critical parameter in this study is sprue diameter and less effective parameter is packing pressure.
Model equations are also developed in this study.

Quality is one of the most crucial elements for manufactured products. Good product quality will increase customer loyalty and hence, higher profit for the company. SR company is a Small Medium Enterprises (SMEs) that produces bread products. Among various kinds of bread products, brioche is the main product with an average production of approximately 1000 pcs per day. In addition, brioche bread also has numerous defective products with an average of 3%-5% per 1000 pcs. However, brioche is a product baked at high temperatures, and hence, the timing of the production staff is crucial to prevent defectiveness. In this work, we use the Taguchi method to obtain factors that produce defective products and mainly the optimal factors combination. The Taguchi method uses the experimental design approach. Therefore, we chose some production factors for the experimental design, namely: baking time (factor A), baking temperature (factor B), water volume (factor C), and yeast amount (factor D). According to the results, the baking time produces the defective products significantly with a 74.4% contribution. Furthermore, we found that the optimal production factors combination is 14 minutes of baking time, 220 Celcius of baking temperature, 20 litres of water, and 7 ounces of yeast. Moreover, based on data processing using the statistical approach, the suggested design of factors combination can reduce the defective products up to 2.68% per day.

In this study, three mixtures of methylyltriphenylphosphonium bromide (MTPPB) as hydrogen bond acceptor (HBA) and N-methyl diethanolamine (MDEA) as hydrogen bond donor (HBD) component was used to prepare transition temperature mixtures (TTMs) into different mole ratios of 1:7, 1:10 and 1:16 HBA/HBD. Two important physicochemical properties of TTMs such as density and refractive index were investigated at the atmospheric pressure and temperature ranges of (293.15-353.15) K and (293.15-343.15) K, respectively. The experimental density data were used to derive the molar volume, molecular volume, lattice energy and isobaric thermal expansion coefficients. With the help of experimental refractive index data, the electronic polarization, molar refraction, and free volume were calculated at the whole temperatures. Several empirical equations were used to correlate refractive indices such as an empirical equation and one-parameter equations (Dale-Gladstone, Eykman, Lorentz-Lorenz, Newton, Arago-Biot, and Oster). Finally, the response surface methodology (RSM) was applied to evaluate the effects of two main factors such as temperature and mole ratio on the density and refractive index of TTMs. The results revealed that the molar ratio has almost a higher effect on the studied properties than temperature.

- by Hosein Ghaedi and +1
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- Statistical Design of Experiment (DoE), Refractive Index, CO2 capture, Deep Eutectic Solvents

This paper describes the numerical optimization of an axial fan focused on the blade and guide vane (GV). For numerical analysis, three-dimensional (3D) steady-state Reynolds-averaged Navier-Stokes (RANS) equations with the shear stress transport (SST) turbulence model are discretized by the finite volume method (FVM). The objective function is enhancement of aerodynamic performance with specified total pressure. To select the design variables which have main effect to the objective function, 2k factorial design is employed as a method for design of experiment (DOE). In addition, response surface method (RSM) based on the central composite design applied to carry out the single-objective optimization. Effects on the components such as bell mouth and hub cap are considered with previous analysis. The internal flow characteristics between base and optimized model are analyzed and discussed.

this book contains basic concepts of experimental design and analyses of different designs in SAS. it starts with comparative experiment and extends the concept to the classical one way ANOVA's such as CRR, RCBD,LATIN SQUARE (The replicated and un-replicated), the lattice and alpha lattice design and incomplete block design; the two way ANOVA's that done in factorial experiment (the replicated and un replicated).
the analyses in these design are demonstrated using SAS.

- by dejene demisie
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- Statistical Design of Experiment (DoE)

Blends consisting of commercial poly(lactic acid) (PLA), poly(lactic acid) oligomer (OLA8) as plasticizer and a
sulfonic salt of a phthalic ester and poly(D-lactic acid) as nucleating agents were prepared by melt extrusion, following a
Mixture Design approach, in order to systematically study mechanical and thermal properties as a function of composition.
The full investigation was carried out by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis
(DMTA) and tensile tests. The crystallization half-time was also studied at 105 °C as a function of the blends composition.
A range of compositions in which the plasticizer and the nucleation agent minimized the crystallization half-time in a synergistic
way was clearly identified thanks to the application of the Mixture Design approach. The results allowed also the
identification of a composition range to maximize the crystallinity developed during the rapid cooling below glass transition
temperature in injection moulding, thus allowing an easier processing of PLA based materials. Moreover the mechanical
properties were discussed by correlating them to the chemical structural features and thermal behaviour of blends.

- by SMK Fehri
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- Statistical Design of Experiment (DoE)

Notre intérêt s’est porté sur le plafond de verre en milieu organisationnel et les
variables permettant de le franchir, parmi lesquelles les compétences politiques (Watkins &
Smith, 2014). L’objectif de cette étude est d’évaluer si l’estime de soi médiatise l’effet des
compétences politiques, ainsi que celui de leurs quatre dimensions, sur le statut au travail.
Pour ce faire, 201 participants ont répondu à un questionnaire en ligne comprenant les items
des compétences politiques conceptualisées en milieu organisationnel français (Borteyrou,
Dagot & Rudelle Astié, 2018), l’échelle d’estime de soi de Rosenberg (Delbrouck, Venra,
Goulet & Ladouceur, 2011) ainsi que cinq questions portant sur leur statut au travail
(Djudevic & al, 2017).
Les résultats ont montré un effet médiateur significatif de l’estime de soi entre les
compétences politiques et le statut au travail. Parmi les quatre dimensions, l’estime de soi
médiatise de manière significative trois d’entre elles (accès à la connaissance formelle,
influence interpersonnelle, propension à la formation), mais ne médiatise pas le lien entre
l’habileté à créer des relations stratégiques et le statut au travail. Cette étude ouvre la porte à
l’exploration d’autres variables explicatives du statut au travail dans une optique
d’appréhension du plafond de verre.

- by MIMRAN RACHEL
- •
- Management, Psychology, Statistics, Feminism

A pressure vessel designed to work under a high internal pressure condition, so selecting material and the vessel's design are the most crucial parts. This paper compares the conventional (solid) pressure vessel made of a steel s515-gr70 and composite material pressure vessel made of epoxy carbon. The static deformation and von-mises stress for a pressure vessel were calculated and compared with composite and multi-layered composite material. The main objective of this paper is to compare the conventional (solid) pressure vessel with composite material pressure vessel and multi-layered composite pressure vessel and find out the best suitable material and design for the pressure vessel. To reduce the stress on the object, we are designing the multilayer vessel and calculating the deformation and stress-induced in the vessel. All these values compare with all other material combinations and conclude which composite is the most suitable and efficient pressure vessel.

- by ANANTHARAMA BAIPADITHAYA and +1
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- Discourse Analysis, Solid State Physics, Design, Medical Device Design

An axial flow fan, which is applied for ventilation in underground spaces such as tunnels, features a medium-large size, and most of the blades go through the casting process in consideration of mass production and cost. In the casting process, post-work related to roughness treatment is essential, and this is a final operation to determine the thickness profile of an airfoil which is designed from the empirical equation. In this study, the effect of the thickness profile of an airfoil on the performance and aerodynamic characteristics of the axial fan was examined through numerical analysis with the commercial code, ANSYS CFX. In order to conduct the sensitivity analysis on the effect of the maximum thickness position for each span on the performance at the design flow rate, the design of experiments (DOE) method was applied with a full factorial design as an additional attempt. The energy loss near the shroud span was confirmed with a quantified value for the tip leakage flow (TLF) rate through the tip clearance, and the trajectory of the TLF was observed on the two-dimensional (2D) coordinates system. The trajectory of the TLF matched well with the tendency of the calculated angle and correlated with the intensity of the turbulence kinetic energy (TKE) distribution. However, a correlation between the TLF rate and TKE could not be established. Meanwhile, the Q-criterion method was applied to specifically initiate the distribution of flow separation and inlet recirculation. The location accompanying the energy loss was mutually confirmed with the axial coordinates. Additionally, the nonuniform blade loading distribution, which was more severe as the maximum thickness position moved toward the leading edge (LE), could be improved significantly as the thickness near the trailing edge (TE) became thinner. The validation for the numerical analysis results was performed through a model-sized experimental test.

- by Miguel Angel Ortiz Barrios and +1
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- Statistical Design of Experiment (DoE), Optimization, Fishing industry, Response Surface Methodology (RSM)

This study proposed an incorporated simulation–Taguchi model to optimize a petrol station sales rate. In addition, it provided a regression model to forecast the sales rate. Initially, Witness 2014 simulation software© was used to simulate the operating system of a petrol station. Next, the obtained simulation results were used as the input for Taguchi method to optimize the process. Taguchi L4 standard orthogonal array was taken to optimize the petrol station parameters including the number of pumps, number of cashiers and customers’ interarrival times (IATs) to obtain a better sales rate. Three noise factors such as petrol station location, different cashiers and different dispensers considered as potential factors affecting the response. Based on Taguchi methodology, number of pumps and IAT were identified as highly contributing factors on the sales rate. The remaining factor (number of cashier) similarly influences the response, but the effect is not very significant. Therefore, the importance sequence of the sales rate parameter is IATs > number of pumps > number of cashiers. The regression equation was formulated to maximize the sales rate (Liter) and then verified by the confirmation runs.

A pressure vessel is designed to work under a high internal pressure condition, so the selection of material and the design of the vessel are the most important part. In this paper, we are comparing the solid pressure vessel made of a steel s515-gr70 and composite material pressure vessel made of epoxy s-glass, epoxy e-glass and epoxy carbon. The static deformation, von-mises stress and strain energy for a pressure vessel calculated with multilayered composite material. The main objective of the work is to compare the solid pressure vessel with composite material pressure vessel and multi-layered composite pressure and find out the best suitable material and design for the pressure vessel. To reduces the stress on the object here we are designing one more model i.e., multilayer vessel and calculating the deformation and stress and strain energy values from all these values and all other material combinations we conclude which composite is the most suitable and efficient pressure vessel.

The article analyses the influence of the design parameters of the structure of the heat sink with round pins on the junction temperature of the LED system. The study uses design of experiment (DOE) and thermal simulations to determine the factors that have the greatest impact to improve the cooling capacity and finding the optimal heat sink design. The results of thermal design and simulation of the LED system have been validated experimentally using a thermocouple and they show that the error between the experimentally measured and simulated temperature value of optimized heat sink structure is below 6%.

Glass woven fabric is produced by interlacing fine fibres of glass (commonly known as fibreglass). A single-strand of these fibres has greater specific tensile strength than that of a steel wire of the same diameter. Due to its lightweight and strong tensile properties, glass woven fabric offers numerous benefits in many industries. Since it is impractical to use conventional methods for cutting the glass woven fabric, a CO2 laser seems to be an appropriate tool for such application. In the present study, an investigation is carried out to characterise the effects of laser cutting parameters, namely, laser power, cutting speed, compressed air pressure and stand-off distance, on the kerf width of the cut. Taguchi design of experiment is employed to account for the interaction between various process parameters, and their significance is further evaluated using ANOVA technique. This study indicates that laser power has dominant effect on the kerf width.

- by KHASHAYAR DANESH NAROOEI
- •
- Laser, Machining, Statistical Design of Experiment (DoE), ANOVA

This paper presents statistical analyses of effects and efficacies of NPK fertilizer levels on yield of four differentspecies of yam in three different locations of kwara state Nigeria. Four quantitative and equally spaced levels0kg/ha, 22.5kg/ha, 45kg/ha and 76kg/ha respectively, of the fertilizer type were considered in the experiment.Factorial design model was used in collecting data sets on yield variables of the plant, using fixed effects, in anexperiment conducted by the Kwara Agricultural Development Project (KWADP) Ilorin, in the year 2012. Thefour varieties of yam examined included white yam, water yam, aerial yam and bitter yam respectively.Observations were taken from Ekan-Meje, Omu-Aran and Omupo locations of the state on a number of responsevariables namely, number of yam plants, number of yam tubers and weight (kg) of yam tubers. Beforeconducting ANOVA, the data sets were inspected for homogeneity of error variances using Fligner-Killeen testin the R statistical packag...

Aspergillus terreus, a fungus commonly used in pharmaceutical industry to produce lovastatin and other secondary metabolites, has been reported to have beneficial biological properties. In this study the exopolysaccharides (AT-EPS) produced by A. terreus were evaluated as potential modulators of certain functions of macrophages. The production parameters for EPS obtained from the liquid culture broth of the studied fungus were optimized using response surface methodology (RSM) and indicated good correlation between the experimental and predicted values. The optimum conditions for AT-EPS extraction included fermentation at 28 °C, pH 8.79, under 98 rpm of agitation, using 2.39% glucose (carbon source) and 0.957% ammonium nitrate (nitrogen source). Under these optimized conditions, AT-EPS production was 1.34 g/L medium. The chemical analyses showed that AT-EPS was composed by mannose (Man; 40.5 mol%), galactose (Gal; 35.2 mol%), and glucose (Glc; 24.3 mol%), and the spectroscopic (FTIR; NMR) and methylation analyses indicated the presence of galactomannans, β-1,3-glucans, and glycogen-like glucans. AT-EPS was tested on murine macrophages to verify its immunoactivity and the treated cells were able to produce nitric oxide, superoxide anion, TNF-α and interleukin 6 similarly to the positive control cells. Furthermore, the macrophages treated with AT-EPS showed activated-like morphological alterations.

- by Robson Tramontina and +1
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- Biochemistry, Carbohydrate Chemistry, Fungi, Statistical Design of Experiment (DoE)

The document shows the ideas to overcome the deep ignorance on the CI (Confidence Intervals) and on DOE (Design Of Experiments); the first part poses the problem that was originated in the RG (Research Gate): it analyses few of the answers, found in the forum, AND some wrong ideas one can find in Wikipedia; connection with the Test of Hypotheses is given; some figures are provided that make “intuitive” the concept of the Confidence Interval with the Theory (Classical Statistics). The second part considers some cases one can find in a very WWU (World Wide Used) Book: we show that high scores on documents do not prove the Quality of those documents. This paper is especially written to settle the matter for the researchers who use CI and DOE: Researchers must be alert in order to do a good job….Many others cases should be shown: the paper should be 10 times longer; to make the paper shorter … I had to cancel pages providing the ideas on the “Scientificness”, forgotten by many people and other providing ideas misleading the readers taken from Wikipedia.

A stability-indicating reverse phase high-performance liquid chromatography method was developed and validated for simultaneous quantification of apremilast (APL) and betamethasone dipropionate (BD) in bulk as well as drug loaded microsponges. Various mobile phase systems were screened to check the system suitability followed by force degradation analysis to determine APL and BD stability under varying stress conditions. A central composite design model was used to optimize the column temperature and flow rate using Design Expert ® (9.0.1). One factor at a time approach with five independent factors were used to validate the robustness of the method. Finally, APL and BD were precisely and accurately quantified from drug loaded microsponges using the validated method. A favorable separation of APL and BD was obtained on a Phenomenex ® Luna C18 column using a mixture of 50 mM phosphate buffer containing 0.1% triethylamine (pH 6.1) and acetonitrile (60:40%v/v) as mobile phase. Both the drugs were found to be stable when exposed to stressors such as heat-, light-, alkali-, acid-and peroxide-induced degradation. The calibration curves were found to be linear with appreciable limit of detection and limit of quantification. Recovery and percentage relative standard deviation of peak areas for APL and BD were found to be < 2.0% and 99-100% in bulk drug solution and <2.0% and 99-103% in microsponge formulation, respectively. Statistical analysis using analysis of variance indicated that the model was significant (P < 0.001). Hence, the developed method can be effectively used to quantify APL and BD, both in bulk as well as microsponge formulations.

This is the second part of a series of reports dealing with the optimal significance level and optimal sample size in statistical hypothesis testing. In this opportunity, the following tests of variances are discussed: Chi2-test for a single sample and F-test for two samples (also including ANOVA). The analysis presented is similar to the one previously used for the tests of means. First, the resolution of the test is defined, in this case by means of an equivalent Cohen distance for the variance. A default value is determined considering the minimum degrees of freedom required for each test. Using this default value, an optimal significance level is obtained for each sample size by minimizing the total test error, which is then used for determining the Dvalue (decision value) of the test. The relationship between sample size and test error is then used to optimize the sample size by minimizing the cost of testing, based on the particular cost ratio (erroneous conclusion vs. single observation) of the test. Due to the analytical complexity of the functions involved, only empirical approximations are obtained. These functions are implemented in R language, and then they are used for solving different illustrative problems.

- by Daniela Castro
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- Statistical Design of Experiment (DoE)

Taguchi methodology was implemented to optimize and evaluate the effect of process parameters such as the applied pressure and time of holding on the tribological properties of ultra-high molecular weight polyethylene (UHMWPE) nanocomposite reinforced with different loadings of silicon carbide (SiC) nanoparticles. An L 9 orthogonal array was used to design experimental matrix in terms of pressure, holding time, and the loading of SiC. UHMWPE/SiC nanocomposites were synthesized via ultrasonication and hot pressing. Pin on disk wear tests were carried out on the composites to evaluate the tribological properties such as specific wear rate and coefficient of friction. Friction and wear response were analyzed using analysis of variance and regression models. The effect of each parameter and optimal process parameters that result in minimum friction and specific wear rate were determined. The confirmation tests carried out verified the validity of the developed experimental design model.

- by Dahiru Lawal
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- Polymer Engineering, Polymer Chemistry, Polymer science, Polymers