High performance fibers production process using Taguchi experimental design

In this research, results of an experimental interaction effect of operating parameters on tensile strength carbon fibers from a commercial PAN-based precursor are investigated. Ten parameters at two and four levels (L₃₂=2¹×4⁹) were investigated: stabilization temperature at first stage (STFIS), stabilization duration time at first stage (SDTFIS), stabilization temperature at second stage (STSS), stabilization duration time at second stage (SDTSS), stabilization temperature at third stage (STTS), stabilization duration time at third stage (SDTTS), stabilization temperature at fourth stage (STFOS), stabilization duration time at fourth stage (SDTFOS), carbonization temperature (CT), and carbonization duration time (CDT). In this study, Taguchi method was used initially to plan a minimum number of experiments. Statistical analysis, analysis of variance (ANOVA), was also employed to determine the relationship between experimental conditions and yield levels. ANOVA was applied to calculate sum of square, variance, ratio of factor variance to error variance and contribution percentage of each factor on response. The results show that increasing all of parameters improves tensile strength performance. The optimum levels of influential factors, determined for tensile strength are STFIS 200 °C, SDTFIS 120 min, STSS 225 °C, SDTSS 120 min, STTS 240 °C, SDTTS 120 min, STFOS 260 °C, SDTFOS 60 min, CT 1400 °C and CDT 10 min. The results showed that CT and ODTFIS are the most and the less effective factors on response, respectively.     

Optimization of the needle punching process for the nonwoven fabrics with multiple quality characteristics by grey-based taguchi method

This study is intended for finding out the optimal processing parameters for needle punching nonwoven fabrics in order to work out its maximal strength. Taguchi method together with grey relational analysis is employed to resolve the problem as regards multiple-quality optimization, and further discover the optimal combination of processing parameters for needle punching nonwoven fabrics. Firstly, orthogonal array L₁₈(2¹×3⁷) is used to deal with the processing parameters that may exert influence over the manufacturing of needle punching nonwoven fabrics. Then grey relational analysis is applied to resolve the deficiency of Taguchi method that focus on single quality characteristic. Next, the response table of grey relational analysis is used to obtain the optimal combination of processing parameters for multiple quality characteristics. In the current experiment quality characteristic refers to the tensile strength and tear strength of the nonwoven fabrics. Additionally, signal-to-noise ratio (SN ratio) calculation and analysis of variance (ANOVA) can be adopted to explore the experimental results. Through ANOVA, the significant factors that exert comparatively significant influence over the quality characteristic of the needle punching nonwoven fabrics, that is, the control factors are determined so that the quality characteristic of the needle punching nonwoven fabrics can be effectively controlled. Finally, confirmation experiment is conducted within 95 % confidence interval to verify the experimental reliability and reproducibility.     

Analysis and construction of a quality prediction system for needle-punched non-woven fabrics

In this study, polyester and polypropylene staple fibers were selected as the raw material, and then processed through roller-carder, cross-lapper and needle-punching machine to produce needle-punched non-woven fabrics. First, the experiment was planned using the Taguchi method to select processing parameters that affect the quality of the needle-punched non-woven fabric to act as the control factors for this experiment. The quality characteristics were the longitudinal and transverse tensile strength of the non-woven fabric as well as longitudinal and transverse tear strength. The L₁₈ (2¹×3⁷) orthogonal array was selected for the experiment as it offered an improvement on the traditional method that wastes a lot of time, effort and cost. By using the analysis of variance (ANOVA) technique at the same time, the effect of significant factors on the production process of needle-punched non-woven fabrics could be determined. Finally, the processing parameters were set as the input parameters of a back-propagation neural network (BPNN). The BPNN consists of an input layer, a hidden layer and an output layer where the longitudinal/transverse tensile and tear strength of the non-woven fabric were set as the output parameters. This was used to construct a quality prediction system for needle-punched non-woven fabrics. The experimental results indicated that the prediction system implemented in this study provided accurate predictions.     

Optimization of multiple quality characteristics for polyether ether ketone injection molding process

This study examines multiple quality optimization of the injection molding for Polyether Ether Ketone (PEEK). It also looks into the dimensional deviation and strength of screws that are reduced and improved for the molding quality, respectively. This study applies the Taguchi method to cut down on the number of experiments and combines grey relational analysis to determine the optimal processing parameters for multiple quality characteristics. The quality characteristics of this experiment are the screws’ outer diameter, tensile strength and twisting strength. First, one should determine the processing parameters that may affect the injection molding with the L₁₈(2¹×3⁷) orthogonal, including mold temperature, pre-plasticity amount, injection pressure, injection speed, screw speed, packing pressure, packing time and cooling time. Then, the grey relational analysis, whose response table and response graph indicate the optimum processing parameters for multiple quality characteristics, is applied to resolve this drawback. The Taguchi method only takes a single quality characteristic into consideration. Finally, a processing parameter prediction system is established by using the back-propagation neural network. The percentage errors all fall within 2%, between the predicted values and the target values. This reveals that the prediction system established in this study produces excellent results.     

Investigation and modeling of air permeability of Cotton/Polyester blended double layer interlock knitted fabrics

The aim of this study was to analyze and model the effect of knitting parameters on the air permeability of Cotton/Polyester double layer interlock knitted fabrics. Fabric samples of areal densities ranging from 315–488 g/m² were knitted using yarns of three different cotton/polyester blends, each of two different linear densities by systematically varying knitting loop lengths for achieving different cover factors. It was found that by changing the polyester content in the inner and outer fabric layer from 52 to 65 % in the double layer knitted fabric did not have statistically significant effect on the fabric air permeability. Air permeability sharply increased with increase in knitting loop length owing to decrease in fabric areal density. Decrease in yarn linear density (tex) resulted in increase in air permeability due to decrease in areal density as well as the fabric thickness. It was concluded that response surface regression modeling could adequately model the effect of knitting parameters on the double layer knitted fabric air permeability. The model was validated by unseen data set and it was found that the actual and predicted values were in good agreement with each other with less than 10 % absolute error. Sensitivity analysis was also performed to find out the relative contribution of each input parameter on the air permeability of the double layer interlock knitted fabrics.     

Effect of Extrusion Conditions and the Optimization of Phenolic Compound Content and Antioxidant Activity of Wheat Bran Using Response Surface Methodology

The extrusion process (EP) consists of heat and mechanical treatments under different conditions of moisture, shear, and pressure and rapidly causes structural alterations and changes in the functional properties of the extruded material. The aim of this study was to evaluate the effect of extrusion conditions and optimize the wheat bran extrusion conditions to achieve the greatest content of phenolic compounds and antioxidant activity using response surface methodology. The EP factors evaluated were feed moisture (FM) (25–33.54%) and final extrusion temperature (T) (140–180 °C). The properties evaluated in the extruded material were bound total phenol content (BTPC), total phenolic compounds and antioxidant activity (AOX). Analysis of variance (ANOVA) and response surface methodology were used in the evaluation. The determination coefficients, (FM)² and (T)², very significantly affected the BTPC and bound 2,2-diphenyl-1-picrylhydrazyl content (BDPPHC). The optimization was performed by overlaying two contour plots to predict the best combination regions. The optimized extrusion conditions were the following: FM?=?30% and T?=?140 °C, which provided BTPC?=?3547.01 μgGAE/g (predicted: 3589.3 μgGAE/g) and BDPPHC?=?9.5 μmolTE/g (predicted: 10.4 μmolTE/g); and FM?=?30% and T?=?180 °C, which provided BTPC?=?3342.3 μgGAE/g (predicted: 3727.7 μgGAE/g) and BDPPHC?=?9.5 μmolTE/g (predicted: 9.3 μmolTE/g). The EP increased the phenolic compounds and AOX, and enhancement of these properties in wheat bran products could make them functional foods.     

Combining Taguchi Method with fuzzy inference on process optimization for fiber manufacturing

Lack of natural textile resources, the present textile industry in Taiwan usually uses pre-oriented yarn (POY), kind of artificial fibers, to make yarns. The POY is wound from continuous spinning of esterification and superposition of plastic pure terephthalic acid (PTA) and ethylene glycol (EG). According to yarn assessment indicators, yarn breakage of POY is crucial. And the broken filament and toughness are the most two important indicators causing yarn breakage during quality measurement. This study applies Taguchi Method to jointly consolidate broken filament degradation rate and toughness elongation percentage to establish a proper orthogonal array. The experimental control factors includes knotting device type, winding tension (CN), oil rate (%), and knotting pressure (kg/cm²), and a L ₁₈(2¹×3⁷) orthogonal array is established. The key parameter design of control factors can be found by Taguchi experiment. The fuzzy inference is combined with Taguchi multiple quality characteristics to construct the process parameter module to effectively increase product yield.     

A combined Taguchi and response surface approach to improve electret charge in corona-charged fibrous electrets

In this work, an attempt was made to model, analyze, and optimize corona charging process for production of fibrous electrets using a combined Taguchi and response surface approach. The key process variables determining the magnitude and duration of electret charge were screened out using Taguchi approach and optimized using response surface approach. The simultaneous optimization of magnitude as well as duration of electret charge led to an initial surface potential of 1.6 kV and half-decay time of 11.18 min.     

The evaluation of evenness of nonwovens using image analysis method

Authors studied on the applicability of image analysis technique using a scanner with a CCD (charged coupled deviced) to the evaluation of evenness of nonwovens because it has distinctive features to considerably save time and labor in the analysis compared with other classical methods. As specimens for the experiment, two different types that are unpatterned and patterned ones were prepared. For the unpatterned specimen, webs were chermically bonded, while for the patterned specimen, webs being thermally calendered with engraved roller. Several webs having various areal densities were prepared and bonded. Coefficient of variation (CV%) was used as a parameter to evaluate the evenness. Scanning conditions could be suitably set up through comparing the total variance to the between-group variance and to the within-group variance, respectively, on the images scanned at the different conditions. The 2D convolution method with smoothing filter kernel was introduced to further filter the noises on the scanned images. After the filtering process, the increase of web areal densities gave an uniform decrease of the CV%. This showed that the scanned image analysis with proper filtering process could be successfully applicable to the evaluation of evenness in nonwovens.     

Implementation of Taguchi methodology in optimization of developed jigs and fixtures for production of paddy weeder

Chhattisgarh is one of the major rice growing states of India, and paddy is the main crop, cultivated in about 76 % of area under agriculture. Mechanical weed control helps reduce the drudgery involved in manual hoeing. Manufacturing process of paddy weeder involves several operations that are to be performed sequentially, repeatedly, effectively, and hence, emphasis is to perform all the operations more efficiently as well. Jigs were designed with the help of software Solid Works and were then developed at the Faculty of Agricultural Engineering, Raipur. The saving in cost of weeding was 60 %, and saving in time was 65 % compared to manual weeding. The improved jigs facilitated the production in 60 % of time taken by traditional jigs. Taguchi method was used to solve the problems related to improving the yield and productivity. Taguchi’s design of experiments (DOE) helped pin-point the source of yield and increase the yielding efficiency. The DOE based on L8-orthogonal array of Taguchi methodology were implemented. The paper outlines Taguchi methodology to optimize the control factors having high and low settings in the production of paddy weeder. The analysis of the results showed that the optimal combination for minimum time consumption in production process is maximum number of bending with minimum welding operation and minimum number of drilling operations. The optimized process by implementation of Taguchi methodology showed a reduction of 30 % in average production time.     

Effect of fiber and fabric constructional parameters on dynamic behavior of compression athletic wear

Compression athletic wear (CAW) is used in number of active sports like jumping, running and power lifting etc. to enhance the performance of an athlete. Compression efficiency is mainly determined by interface pressure exerted by it but pressure reduces with time due to prolonged stretching and deformation of fabric. In this study, compression behaviour was evaluated by measuring the interface pressure drop and recovery characteristics of CAW. Interface pressure over a long duration of time was measured using a dynamic leg segment prototype. Recovery characteristic was evaluated by measuring the residual shrinkage at different time interval using cyclic fatigue test. The effect of filament cross sectional shape, Lycra® linear density and fabric tightness on compression properties was found to be statistically significant by ANOVA. Fabric with high tightness factor, coarse Lycra® and profiled polyester was observed to have better recovery and compression efficiency as compared to other fabrics under study.     

不同橡胶林对土壤容重及田间持水量的影响研究

为了研究同一区域内不同橡胶林对土壤容重及田间持水量的影响程度,以云南河口抗逆高产、胶木兼优和RRIM600作为研究对象,对土壤容重及田间持水量进行3年调查,结果表明：(1)橡胶林土壤容重为1.09～1.37 g/cm3,相同深度土壤容重相差较小,但随着土壤深度增加,土壤容重逐渐升高,表层土0～20 cm土壤容重显著低于20～40 cm土层;(2)胶木兼优、抗逆高产和RRIM600田间持水量平均值分别为36.92%、35.19%和34.90%,表现为胶木兼优＞抗逆高产＞ RRIM600,但三者田间持水量均随土壤深度增加逐渐降低,0～20 cm土层高于20～40 cm土层;(3)同一橡胶林下不同深度土壤之间,其土壤容重、田间持水量均存在非显著正相关,而相同深度土壤容重与田间持水量之间存在极显著负相关。     

Manufacturing technique and acoustic evaluation of sandwich laminates reinforced high-resilience inter/intra-ply hybrid composites

This study focused on the fabrication and acoustic property evaluation of sandwich cover-ply-reinforced highresilience thermal-bonding nonwoven hybrid composites. P-phenyleneterephthalamides and bicomponent high-resilience bonding polyester intra-ply hybrid nonwoven fabrics were compounded with glass plain fabric to produce the high strength sandwich structural cover ply by means of needle punching and thermal bonding to reinforce the whole composites and dissipate energy when being impacted. Then, the acoustic absorption properties of the homogenous intra-ply hybrid meshwork layer were investigated before and after being reinforced with the aforementioned cover ply. The influencing factors, including areal density, fiber blending ratio, needle punching depth, and air cavity thickness between back plate of the impedance tube and composites, were comparatively investigated. Results revealed that hybrid composites exhibited exceedingly high acoustic absorption properties. Acoustic absorption coefficients were promoted with increases in areal densities and fiber blending ratio of 3D crimped hollow polyester, particularly at low-mid frequency range. In addition, needle punching depths and back air cavity thicknesses considerably affected the average absorption coefficients. The meshwork center layer reinforced with sandwich structural cover-ply perform high resilience properties.     

Optimal design of nonwoven air filter media: Effect of fibre shape

In this work, a series of needle-punched nonwoven filter media was prepared by using polyester fibres of three different cross-sections (circular, trilobal, and deep-groove) in accordance with a three-component augmented simplex lattice design. The experimental data of filtration efficiency and pressure drop were analyzed by means of response surface methodology. Statistical model equations were developed for filtration efficiency and pressure drop by using Design-Expert^® software. The filtration efficiency and pressure drop were expressed as linear functions of proportion of fibres of different shapes. Statistical checks (ANOVA, R ² and p-value) indicated that these models were adequate for representing the experimental data. By means of contour plots, the effect of filter constituents on filtration performance was analysed. The filter media consisting of deep-grooved fibres exhibited highest filtration efficiency but at the cost of highest pressure drop. On the other hand, the filter media consisting of circular fibres displayed lowest pressure drop but at the cost of lowest filtration efficiency. As a compromise for simultaneously achieving maximum filtration efficiency of 61.52 % and minimum pressure drop of 13.6 Pa, the optimum mixture was predicted to consist of 53.7 % deep grooved fibres and 46.3 % circular fibres. The predicted response was found in close agreement with the experimental data. This demonstrates the effectiveness of the approach reported here for achieving good predictions, while minimizing number of experiments.     

Stab-resistant property of the fabrics woven with the aramid/cotton core-spun yarns

Aramid fibers are mainly used for industrial applications and human body protection against ballistic threats. But they are used mostly in forms of composites. And fabrics woven with a high yarn count offer a moderate protection performance against the knife stabbing due to the low shear strength. This research is focused on investigating the effect of the aramid core-spun yarns on the stab resistance of the woven fabrics. With the aramid core-spun yarns with core to sheath weight ratio of 1 to 2.5 the armor specimens having different fabric densities were prepared and the knife edge impact test was conducted. On the impact energy of the knife at the level 1 according to the NIJ standard, the drop tower test results demonstrated that fabric density of the armor specimens affected the stab resistance significantly. The penetration depth of the impactor through the armor specimens was associated with the thickness and mass of the armor sample in different ways. Being the stab resistance introduced by considering the penetration depth of the impactor via thickness and weight per surface area, the effects of the fabric conditions on the anti-stabbing property could be systematically analyzed and turned out that there was an optimal level of the fabric density, showing the most effective stab resistance.     

黄淮区不同播种方式对玉米出苗质量和土壤环境的影响

在黄淮平原小麦玉米两熟区,通过不同还田条件、播深和镇压3因素裂区试验,研究免耕条件下玉米出苗的土壤环境及出苗质量。结果表明,秸秆还田与不还田显著影响玉米出苗质量,表现为黄化、弱苗率差异显著;秸秆还田下播深对出苗质量有显著影响,镇压对出苗质量影响不显著。3因素交互效应对土壤环境影响程度依次是水分>硬度>温度。     

Root characteristics of temperate pasture in New South Wales after grazing at three stocking rates for 30 years

The distribution of length, diameter, surface area and volume of roots was measured in northern New South Wales, Australia, under temperate pasture that had been previously grazed at low and high stocking rates for 30 years; these root characteristics were compared with those of roots under ungrazed pasture. The ungrazed pasture was dominated by Phalaris (Phalaris Aquatica), whereas annual grasses and dicotyledons were a large component of the pasture at low and high stocking rates. A fine-meshed (0.250 mm) sieve was used for separating the roots from the soil, and the root characteristics were measured using image analysis techniques. With this sieve size, root length densities were many times higher than published data for astures where a larger mesh sieve had been used for sample preparation. The lengths of root per unit of soil volume (root length densities) were high for all stocking rates and averaged 91 cm cm^?3 near the soil surface (0 – 5 cm) declining to 4.0 cm cm^?3 at the deepest depth measured (65–75 cm). There was a greater proportion of roots near the soil surface at the higher stocking rates. A greater proportion of fine roots occurred at the higher stocking rates, which was probably due to the differences in botanical composition. Reciprocal, power and logarithmic functions best described the distribution of root length density, root surface area density and root volume density, root surface area density and root volume desnity with depth.     

花后高温胁迫对小麦灌浆特性及产量的影响

为了解小麦灌浆特性对花后高温胁迫的响应,选用西农979、洛旱2号、西农2208、新麦11、郑麦366和兰考矮早8等6个品种,于2016-2018年以自然条件为对照(CK),分析了花后高温胁迫(搭棚增温)后小麦灌浆进程、千粒重和产量的变化。结果表明,小麦粒重主要由灌浆持续时间和灌浆速率决定,不同小麦品种对花后高温胁迫的响应模式不同。西农979、洛旱2号在高温胁迫下,灌浆快增期的平均灌浆速率有所提高,但灌浆持续时间显著降低,导致粒重显著下降,且两年度的千粒重热感指数和产量热感指数均大于1,属于不抗高温型品种;新麦11、郑麦366和兰考矮早8经高温胁迫后,灌浆持续时间变化幅度不大,平均灌浆速率分别降低了0.05、0.09和0.06g·d^-1,千粒重分别降低了2.00、1.45和1.56g,但高温胁迫下粒重与CK无显著差异,且郑麦366和兰考矮早8的千粒重热感指数和产量热感指数在两个年度均小于0.9,属于抗高温型品种。     

Yield and yield components of saffron under different cropping systems

This study was conducted to evaluate yield and yield components of saffron (Crocus sativus L.) in response to (i) production system (PS) (irrigated vs. non-irrigated); (ii) corm size (CS) (medium −2.25 to 3 cm diameter vs. small corms <2.25 cm diameter); (iii) planting depth (PD) (10 cm vs. 20 cm); and iv) planting density (PDEN) (51 corms m⁻² vs. 69 corms m⁻²).This fully replicated multifactorial design was started in August 2000, and carried through November 2003, when the fourth saffron harvest took place. The total and average fresh weight of stigmas, and the number of flowers were measured at each harvest.Results indicate that three of the four factors tested (PS, CS and PD) had a significant effect on the quantitative yield during the two most productive flowering years (2001 and 2002) and on the total flowering. Irrigated cultivation, medium size corms and 10 cm planting depth had the greatest effect in increasing the quantitative production of saffron.Yield was also affected by planting density in contrasting ways. Whereas at high PDEN yield increased per unit of surface, at low PDEN, yield increased with respect to the initial number of corms planted.The fresh weight of stigmas per flower yield component, an important aspect that determines the quality of the spice, was enhanced when corms were planted at 20 cm depth and when irrigation was applied to the crop.     

Optimization of melt-spinning parameters of poly(ethylene terephthalate) partially oriented multi-filament yarn in an industrial scale: Central composite design approach

In this study, central composite design (CCD) based on response surface methodology (RSM) was employed to optimize parameters of melt-spinning process of poly(ethylene terephthalate) partially oriented multifilament yarn (POMFY). On the basis of a four-variable CCD, RSM was used to determine the effects of spinning temperature, spinning pressure, take-up velocity and quenching air velocity on the levels of the elongation of POMFY as the response. The POMFY samples were also characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. By applying a quadratic regression analysis, an equation indicating the effect of each variables on the response was developed. The predicted values of the parameters showed excellent agreement with the experimental values (R ²=0.9565, Adjusted-R ²=0.916). Moreover, the results confirmed that the CCD mathematical model was a suitable method to optimize the melt-spinning parameters of POMFY in an industrial scale.