Taguchi Experimental Design Method Research Articles

Preparation and Characterization of Pour‐Casting Red Phosphorus Smoke Agents with HTPB as Binder

AbstractThe main aim of this study is to develop the vacuum pour‐casting process of the red phosphorus smoke agents. The typical composition of MK 58 marine location marker prepared by tamp‐casting process is red phosphorus (RP)/magnesium (Mg)/manganese dioxide (MnO2)/zinc oxide (ZnO)/epoxy resin (ER), which was selected as the original formula. Epoxy resin (ER) was replaced by hydroxyl terminated polybutadiene (HTPB) as the binder. First of all, simultaneous differential scanning calorimetry‐thermogravimetric analysis (STA DSC‐TGA) and vacuum stability tester (VST) were used to analyze the thermochemical characteristics, stability and chemical compatibility of the formula. Afterwards, Taguchi's experimental design method was used to design nine experimental conditions by way of orthogonal array with four control factors and three levels, and the scaled‐down smoke pellets were prepared using the vacuum pour‐casting method. The combustion phenomenon of these smoke pellets was recorded by the visual‐image capture system, and the flame temperature was measured by the temperature measurement system. The burning rate was chosen as the quality characteristic to analyze the optimal parameter combination of minimum burning rate. In addition, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM‐EDS), tensile testing machine (TTM) and hardness tester (HT) were employed to observe the uniformity of the composition distribution in the pellet and to measure the mechanical strength and hardness of the pellets. Smoke density test chamber (SDTC) was used to measure the specific optical density of smoke generated by RP smoke agent. Finally, the operating conditions of the optimal parameter combination determined by Taguchi method were used to prepare the full‐size smoke candle, and its burning performance was verified and the feasibility of the vacuum pour‐casting technology was evaluated. The experimental results indicated that the optimal combination of parameters was the RP mixture/HTPB mass ratio of 84 : 16, the NCO/OH ratio of IPDI to HTPB (R value) of 1.6, the additional DOA of 4.5 wt % and the curing temperature of 50 °C. The prepared scaled‐down smoke pellets had good stability, chemical compatibility, hardness, mechanical properties and burning smoke density. In addition, the burning time and performance of the full‐size smoke candles prepared by vacuum pour‐casting technology also met the requirements.

Alkali activated cement mixture at ambient curing: Strength, workability, and setting time

AbstractThe success of ordinary Portland cement (OPC) comes at a risk to the environment because of the large carbon dioxide emissions associated with cement manufacturing. This has led the scientific community to look for alternative cementitious materials with lower environmental impact. Alkali activated cement (AAC) is an excellent alternative to this end. In this study, the effect of binder content, alkaline solid to binder ratio (AS/B), sodium silicate to sodium hydroxide solids ratio (SS/SH), and total water content to total solid binder ratio (TW/TB) on the strength, setting time and flowability of ambient cured AAC mixtures are studied using Taguchi method of experimental design. Binder content was varied from 550 to 750 kg/m3, AS/B ratio from 0.14 to 0.22, SS/SH ratio from 1.5 to 2.5, and TW/TB ratio from 0.29 to 0.39. The study results showed that within the investigated range, an increase in binder content has a minor effect on strength but resulted in a considerable increase in setting time and flowability. An increase in the AS/B ratio resulted in increased flowability and setting time and a decrease in strength. Moreover, the study also investigated the relationship between compressive strength and flexural strength.

Selective detection of VOCs using microfluidic gas sensor with embedded cylindrical microfeatures coated with graphene oxide

Volatile organic compounds (VOCs) are major environmental pollutants. Exposure to VOCs has been associated with adverse health outcomes. The monitoring of hazardous VOCs is a vital step towards identifying their presence and preventing the risk of acute or chronic exposure and polluting the environment. One of the challenges associated with monitoring VOCs is selectivity of the sensor. Microfluidic gas sensors offer selective and sensitive detection capabilities that have been recently applied for detection of VOCs. In this study, we achieve improved selectivity for detection of a range of VOCs by adding micro- and nanofeatures to the microchannel of microfluidic gas sensors. First, microfeatures are embedded into the microchannel and their geometries are optimized using Taguchi design of experiment method. In the next step the microfeatures embedded microchannel is coated with graphene oxide, to increase the surface to volume ratio by introducing nanofeatures to the surfaces. The nano- and microfeatures are characterized by SEM, XPS, and water contact angle measurement. Finally, the changes in the sensor response are compared to plain microfluidic gas sensor, the results show an average of 64.4% and 120.9% improvement in the selectivity of the sensor with microfeatures and both nano- and microfeatures, respectively

Parameter Optimization of Laser Direct-Write Patterning on Indium Tin Oxide/Polycarbonate Thin Films Using Multi-Performance Characteristics Analysis

Indium tin oxide (ITO) thin films on polycarbonate (PC) substrates were patterned using the laser direct-write (LDW) technique to form an isolation line. The effect of the LDW parameters (power, pulse repetition rate, and defocusing distance) on the isolation line width, depth and roughness of the PC within the line was investigated. Additionally, the Taguchi method of experimental design was applied to determine the optimal parameters of LDW. Results showed that increasing the power led to an increase in the isolation line width and decrease in the surface roughness of the PC within the line. The increase in the pulse repetition rate and defocusing distance caused a decrease in the isolation line width. The optimal parameters were found to be A2B3C3, consisting of power of 5 W, pulse repetition rate of 100 kHz, and defocusing distance of +3 mm. Under these parameters, we obtained an isolation line width of 48.4 μm, and a surface roughness of Ra 38 nm of the PC within the isolation line. We confirmed that the ITO films separated by the isolation lines attained electrical isolation.

Optimal Selection of Backside Roughing Parameters of High-Value Components Using Abrasive Jet Processing

This paper mainly presents a set of new Sapphire Backside Roughing technology. Presently, the associated Sapphire Backside Roughing technology is still concentrated on chemical etching, as its yield rate and efficiency are often limited by lattice structures, and the derived chemical waste fluid after etching is most likely to cause ecological contamination. In this research, refined abrasive jet processing technology is adopted, and in the meantime, the Taguchi experiment design method is taken for detailed experimental planning. Through processing parameter conditions and abrasive selection and development, proper surface roughing and processing uniformity are obtained so as to improve the various weak points of the abovementioned traditional etching effectively. It is discovered that abrasive blasting processing technology is, respectively, combined with wax-coated #1000 SiC particles and wax-coated #800 Zirconium particles to process the sapphire substrate with initial surface roughness 0.8–0.9 μmRa from the experiment. A 1.1–1.2 μmRa surface roughness effect can be achieved about two minutes later. The experimental results show that the actual degree of sapphire substrate surface roughing obtained in the AJM process depends on the gas pressure, impact angle, wax-coated abrasives, and additives. The new Sapphire Backside Roughing technology has high flexibility, which not only meets the requirements for sapphire surface roughing specification but can also effectively reduce the sapphire substrate roughing time and related cost.

Identification and evaluation of cracks in electrostatically actuated resonant gas sensors using Harris Hawk / Nelder Mead and perturbation methods

In this paper we study the static deflection, natural frequency, primary resonance of an electrostatically actuated cracked gas sensor. Besides, a novel hybrid metaheuristic algorithm is proposed to detect the location and depth of possible crack on the microcantilever systems. The gas sensor configuration consists of a microcantilever with a rigid plate attached to its end. The nonlinear effects of the electrostatic force and fringing field are taken into account in the mathematical model. The crack is represented by a rotational spring. In the first part, the effect of crack on the static and dynamic pull-in instability are studied. The equations of motion are solved by the application of the perturbation methods. Next, an inverse problem is formulated to predict the location and depth of the crack in the gas sensor. For that purpose, the weighted squared difference of the analytical and predicted frequency response is considered as the objective function. The location and depth of the crack in the microsystem are determined using the hybrid Harris Hawk and Nelder Mead optimization algorithms. The accuracy and efficiency of the proposed algorithm are compared with the HHO, DA, GOA, and WOA algorithms. Taguchi design of experiments method is used in order to tune the parameters of optimization algorithms systematically. It is shown that the proposed algorithm can predict the exact location and depth of the open-edge crack on an electrostatically actuated microbeam with proof mass.

3D simulation and parametric optimization of a solar air heater with a novel staggered cuboid baffles

Thermal performance enhancement of solar air heaters is critical for efficient utilization of energy. In the present work, a numerical study and parametric optimization of turbulent convective heat transfer in a solar air heater duct with novel staggered cuboid baffles placed on the absorber plate are investigated. The heat transfer and pressure loss characteristics are analyzed, and an optimization procedure based on the Taguchi experimental design method is used to obtain the baffle's optimum geometry and arrangement. The numerical results reveal that the proposed optimum design performs better than the existing ones. It is also indicated that the relative baffle height (c/H) and relative baffle pitch (s/H) are the most influential parameters on the efficiency and thermo-hydraulic performance factor. Also, the thermo-hydraulic performance factor of the optimum baffled solar air heater is 3.43, 2.80 and 2.38 at Reynolds numbers 5080, 7620 and 10160, respectively. Depending on the Reynolds number, the thermo-hydraulic performance factor of the proposed baffled is up to 17.5% better compared with the performance of the best design reported in the literature.

Electrically conductive silicon oxycarbide thin films prepared from preceramic polymers

AbstractThis work focuses on silicon oxycarbide thin film preparation and characterization. The Taguchi method of experimental design was used to optimize the process of film deposition. The prepared ceramic thin films with a thickness of c. 500 nm were characterized concerning their morphology, composition, and electrical properties. The molecular structure of the preceramic polymers used for the preparation of the ceramic thin films as well as the thermomechanical properties of the resulting SiOC significantly influenced the quality of the ceramic films. Thus, an increase in the content of carbon was found beneficial for the preparation of crack‐free thin films. The obtained ceramic films exhibited increased electrical conductivity as compared to monolithic SiOC of similar chemical composition. This was shown to correlate with the unique hierarchical microstructure of the SiOC films, which contain large oxygen‐depleted particles, mainly consisting of highly graphitized carbon and SiC, homogeneously dispersed in an oxygen‐containing amorphous matrix. The matrix was shown to also contain free carbon and to contribute to charge carrier transport between the highly conductive large particles. The ceramic thin films possess electrical conductivities in the range from 5.4 to 8.8 S/cm and may be suitable for implementation in miniaturized piezoresistive strain gauges.

Evaluating the Welding Pulses of Various Tool Profiles in Single-Pass Friction Stir Welding of 6082-T6 Aluminium Alloy

Aluminium alloy 6082-T6 plays a vital role in the fabrication of lightweight structures, especially for the manufacturing of artillery, defense vehicles, and aircraft. Aluminium alloy 6082-T6 is a well-known structural alloy having a high strength-to-weight ratio and favorable corrosion resistance properties in extreme environments. In this study, three friction stir welding (FSW) process parameters (spindle speed, weld speed, and shoulder penetration), two geometrical tool parameters to precisely describe the pin profile, and the shoulder profile were considered at five levels. Optimization was conducted using the Taguchi experimental design method, and FSW experiments were conducted in a conventional milling machine. The parameters were optimized to maximize the tensile strength for various plate thicknesses. The number of tool pin polygon edges determines the corresponding welding pulses. The results show that 105-110 pulses/s is an optimal value to achieve a high-quality, defect-free weld. Key words: Friction stir welding, Aluminium alloy, Welding pulses, Taguchi, Microstructure

Prediction of Surface Roughness after Turning of Duplex Stainless Steel (DSS)

Feed Forward Back Propagation artificial neural network (ANN) model utilizing the MATLAB Neural Network Toolbox is designed for the prediction of surface roughness of Duplex Stainless Steel during orthogonal turning with uncoated carbide insert tool. Turning experiments were performed at various process conditions (feed rate, cutting speed, and cutting depth). Utilizing the Taguchi experimental design method, an optimum ANN architecture with the Levenberg-Marquardt training algorithm was obtained. Parametric research was performed with the optimized ANN architecture to report the impact of every turning parameter on the roughness of the surface. The results suggested that machining at a cutting speed of 355 rpm with a feed rate of 0.07 mm/rev and a depth of cut 0.4 mm was found to achieve lower surface roughness with, an increase in the cutting speed and feed rate with the increases of the surface roughness. In addition, an increase in the depth of cut was found to reduces the surface roughness. The outcome of this study showed that ANN is a versatile tool for prediction of surface roughness and may be easily extended with greater confidence to various metal cutting processes.

Application of bio-cementation to enhance shear strength parameters of soil-steel interface

In this study, the microbially induced calcite precipitation process is introduced to a sandy soil-steel interface. A series of modified direct shear tests designed based on the Taguchi design of experiments method are conducted to examine the bio-cemented soil-steel interface strength parameters. The primary test results are analyzed using the ANOM and ANOVA approaches, and the predictions of the Taguchi method are compared with the test results. The effects of the initial soil moisture content, density ratio of urea/CaCl2, and rate of injection of the cementation solution on the response of the bio-cemented sand-steel interface are scrutinized. Both the ANOM and ANOVA show that the density of the cementation solution is the most influential parameter, while the initial soil moisture content is the least influential factor in the bio-cementation process of the sand-steel interface. The test results show that introducing bio-cementation process to the soil-steel interface is an effective approach in enhancing the interface properties, increasing the sand-steel interface shear strength 3 to 7 times, depending on the normal stress used in the tests. The results also show that the initial moisture content that yields the highest gain in the interface shear strength due to bio-cementation is near the optimum moisture content of the soil obtained from the modified compaction test.

Investigation of the Effective Parameters on the Preparation of Ammonium Perchlorate Particles Using a Cooling Crystallization Process

AbstractAmmonium perchlorate is one of the most important and applicable oxidizers used in solid propellants. Also, the morphology of ammonium perchlorate particles is an effective parameter in the production of propellants. In the current research, the preparation of ammonium perchlorate using the cooling crystallization method was studied. Four parameters including the rate of cooling, mixing patterns, agitator speed, and surfactant were considered in cooling crystallization of ammonium perchlorate. Nine tests were carried out based on the Taguchi experimental design method. The morphology of the obtained crystals was analyzed by optical microscope and MIP 4 student software. The size distribution of the particles was modeled using the Rosin‐Rammler method. Obtained results illustrated that the surfactant had the most effect with the value of 70.7 % and the agitator speed, flow pattern, and cooling rate had fewer effects on the morphology with the values of 25.8 %, 2.9 %, and 0.2 %, respectively. The optimal amount of sphericity obtained by the Taguchi method was 0.77 which was verified by the experimental result of 0.76. The roundness and aspect ratio values for the optimal crystal were 0.79 and 1.40 respectively. Applying the Rosin‐Rammler model showed that the homogeneity factor of size distribution was 2.22 for the optimal crystals.

Setting Time and Strength Monitoring of Alkali-Activated Cement Mixtures by Ultrasonic Testing

Alkali-activated cement (AAC) is a promising binder that replaces ordinary Portland cement (OPC). In this study, the development of setting time and strength of AAC mixes were studied using ultrasonic testing method. The test results were compared with traditional Vicat setting time and compressive and flexural strengths. The findings showed that setting times and strengths have a strong correlation with ultrasonic velocity curve. The initial setting time corresponds well with the ultrasonic velocity curve’s dormant period, and the final setting time with the time it takes to reach the velocity curve’s maximum acceleration. Both setting times also showed a correlation with the value of the maximum acceleration. An exponential relation was found between the ultrasonic velocity and the compressive and flexural strengths. The effect of binder content, alkaline solid to binder ratio (AS/B), sodium silicate to sodium hydroxide solids ratio (SS/SH), and total water to total solid binder ratio (TW/TS) on the strength and setting time are also studied using Taguchi method of experimental design. AS/B ratio showed a significant influence on the setting time of AAC while TW/TS ratio showed only a minor effect. The ultrasonic velocities were able to capture the effect of the different parameters similar to the compressive strength. The velocity decreased mainly with the increase of TW/TS ratio and binder content, while AS/B and SS/SH ratios showed a lower influence.

Optimization and Experimental Validation of Automotive Bulbs

In a vehicle, bulbs called the P-group are responsible for warning other drivers or pedestrians and they are known as signal bulbs. Signal bulbs have been used to emit warning and hazard signs in parts such as brake lights, direction indicator, hazard lights (night vision) as well as tail bulbs and car park alarms. There has been limited researches on the photometric characteristics of these lamps, but a review of these studies revealed that no detailed research has yet been done on optimizing these characteristics, and there is a scientific gap. In this study, factors affecting the service life and luminous flux were evaluated by using Taguchi design of experiments method. The results showed that the two factors of weight percent composition of bubble filling neutral gases and the volumetric efficiency of gases injected into the bubble had the most influence on the target parameters. Experimental results showed that the optimum composition of neutral gases injected into the bulb bubble can extend the bulb service life to approximately 341 h, which is three times the service life of a bulb with the inappropriate composition of fill gases. Then the optimum state of the service life and the luminous flux were determined to meet the reference standards. Although the service life and luminous flux parameters were able to reach 341 h and 513 lumens in the maximized state, however, in the optimum state with satisfying reference standards, the service life and luminous flux were 330 h and 463 lumens, respectively. Then, the bulb bubble filling with inert neutral gases and its effect on the bulb service life was investigated. The results showed that if the volumetric efficiency of gas injection increased from the normal 75%–100%, the service life of the test lamps would be improved by about 10%.

Hybrid artificial electric field algorithm for assembly line balancing problem with equipment model selection possibility

Existence of different models of equipment of the tasks of an assembly line has two major direct effects on the task operational times, and the equipment purchasing cost. This issue is reflected for the first time in this study in a straight assembly line balancing problem with single model product. The problem is formulated first as a non-linear model and then is linearized. Because of the NP-hard nature of the problem some meta-heuristic algorithms are proposed to solve it efficiently. For this aim a complete encoding–decoding​ scheme and the artificial electric field algorithm as a most recent algorithm of the literature and also the simulated annealing algorithm are considered. In order to fit to the problem of this study, some modified and hybrid versions of these algorithms are proposed and are tuned by the Taguchi experimental design method. A very deep computational experiments using 24 modified test problems of the literature show the superiority of the artificial electric field algorithm when is hybridized by the simulated annealing algorithm and a local search phase.

Optimization of Photogrammetric Flights with UAVs for the Metric Virtualization of Archaeological Sites. Application to Juliobriga (Cantabria, Spain)

Three-dimensional models are required to virtualize heritage sites. In recent years, different techniques that ease their generation have been consolidated, such as photogrammetry with Unmanned Aerial Vehicles (UAVs). Nonmetric cameras allow relatively inexpensive data collections. Traditional aerial photogrammetry has established methodologies, but there are not commonly used recommendations for the selection of parameters when working with UAV platforms. This research applies the Taguchi Design of Experiments Method, with four parameters (height of flight, forward and lateral overlaps, and inclination angle of the sensor) and three levels (L9 matrix and nine flights), to determine the set that offers the best metric goodness and, therefore, the most faithful model. The Roman civitas of Juliobriga (Cantabria, North of Spain) was selected for this experiment. The optimal flight results of the average signal-to-noise ratio analysis were height of 15 m, forward and lateral overlaps of 80%, and inclination of 0° (nadiral). This research also highlights the noticeable contribution of the inclination in the accuracy of the model with respect to the others, which is 16.4 times higher than that of the less relevant one (height of flight). This leads to propose avoiding inclination angle as a variable, and the sole development of nadiral flights to obtain accurate models.

A combination of DOE – multi-criteria decision making analysis applied to additive assessment in porous asphalt mixture

ABSTRACT Porous asphalt (PA) mixture is setting off an attractive alternative to be used as surface layer in pavements due to the many profits this mixture provides in terms of noise, safety and environmental aspects. Nonetheless, its use is quite limited due to its low durability in comparison to dense graded asphalt mixtures, reason for which the incorporation of different additives is recommended. In this study, the impact of different types of binders and additives in porous asphalt mixtures are experimentally assessed. A total of 54 experimental designs were defined through the Taguchi design of experiments method. Total air voids, interconnected air voids, particle loss in dry and wet conditions and binder drain down were the responses obtained from the experimental tests. Since more than one response was obtained, three Multi-Criteria Decision-Making (MCDM) methods were performed to turn the multiple response optimisation problem into single-objective optimisation problem. Based on the experimental results and statistical analysis, polymer modified binders improve the ravelling resistance without affecting the functional performance of the mixture and without presenting the risk of binder drain down.

A novel activated carbon from human hair waste: Synthesis, characterization and utilization thereof as an efficient, reusable Ni (II) adsorbent

In this study, the novel hair based activated carbon (HAC) was synthesized from human scalp hair using calcium chloride as an activating agent and characterized using FTIR, Raman, CHNS, BET, SEM, and XRD analysis methods. The Ni (II) adsorption investigations were performed in batch mode experiments by determination of its initial and momentary concentrations in the solution. The effect of pH, adsorbent dose, Ni (II) initial concentration, and adsorption time on HAC adsorptivity, were evaluated using Taguchi experimental design method. Kinetics, isotherms, and regeneration studies were also performed. The optimum values of the four parameters, mentioned above, were found as 5, 1 ​g/L, 27.70 ​mg/L, and 60 ​min, respectively. The Ni (II) adsorption kinetic and isotherm were best described by pseudo-second order and BET models, respectively. After five adsorption-desorption cycles, a very small decrease (6.85%) in adsorbent capacity was observed. According to the BET isotherm model, the maximum multilayer adsorptivity was 63.44 ​mg/g. Due to the simple preparation, ease to scale-up, high adsorptivity, as well as regeneration results, the obtained bio-based activated carbon can be introduced as a strong, stable, and reusable adsorbent of Ni (II).

Cryoprotectant toxicity and hypothermic sensitivity among Anopheles larvae

Laboratory rearing of mosquitoes is commonly practiced by researchers studying mosquito-borne infectious diseases and vector control methods. In the absence of cryopreservation methods to stabilize unique or genetically modified strains, mosquito lines must be continuously maintained, a laborious process that risks selection effects, contamination, and genetic drift. Towards the development of a cryopreservation protocol, several commonly used cryoprotectants were systematically characterized here both individually and as cocktails. Among first instar, feeding-stage An. gambiae and An. stephensi larvae, cryoprotectant toxicity followed the order of dimethyl sulfoxide > ethylene glycol > methanol. The resulting LD50 values were used as the basis for the development of cryoprotectant cocktail solutions, where formulation optimization was streamlined using Taguchi methods of experimental design. Sensitivity to hypothermia was further evaluated to determine the feasibility of cryoprotectant loading at reduced temperatures and slow cooling approaches to cryopreservation. The information described here contributes to the knowledge base necessary to inform the development of a cryopreservation protocol for Anopheles larvae.

Prediction of Surface Roughness of Mild Steel Alloy in CNC Milling Process Using ANN and GA Technique

In this paper, Analysis Of Variance (ANOVA), Artificial Neural Network (ANN), and Genetic Algorithm (GA) have been studied to predict the effect of milling parameters on the Surface Roughness (Ra) during machining of mild steel alloy. The milling experiments carried out based on the Taguchi design of experiments method using (L16) orthogonal array with 3 factors and 4 levels. The influence of three independent variables such as spindle speed (910, 930, 960, and 1000 rpm), feed rate (93, 95, 98, and 102 mm/min), and Tool Diameter (8, 10, 12, and 14 mm) on the Surface Roughness (Ra) were tested and analyzed with (ANOVA) to predict the response which indicates that spindle speed was the most significant factor effecting on Surface Roughness (Ra). Artificial Neural Network (ANN) and numerical methods are used widely for modeling and predict the performance of manufacturing technologies. Neural Network technique with 2 hidden layers, 10 neurons size, 1000 epochs, and Trainlm transfer function is used to predict the result. The Genetic Algorithm (GA) has been utilized to find optimal cutting conditions during a milling process. From the results, the optimal value of spindle speed is (930 rpm), feed-rate is (95 mm/min) and tool diameter is (8 mm). This network structure is capable of predicting the Surface Roughness (Ra) well to optimize the milling parameters. Artificial Neural Network (ANN) predicted results indicate good agreement between the experimental and the predicted values.