Analytical Algorithms for the Blend Ratios by Fibre-bundle Tensile Curves Part Ⅱ: Calculations of the Modulus Method and the Percentage Method

The principles for the modulus method and the percentage method are established and discussed in the part following Part Ⅰ of the series papers, in which we proposed the various algorithms of the strength method and the work method. The samples of Wool/PET blended fibre bundles, the method of fibre-bundle tensile tests and the typical specific stress-extension curves from the fibre bundles with different blend ratios are the same as in Part Ⅰ. It can be found that the theoretical results estimated by the modulus and percentage methods accord with the experimental values highly though the calculations of the two methods are slightly more complex than those of the strength and work methods. Especially, using the modulus method can not only avoid the influence of the error caused by the determination of the tensile curve of no fibre breaking in stretching, Y(e), but also need not to know the tensile curves of mono-component fibre bundles in certain calculation. The latter advantage of the modulus method exists in the percentage method too, but it should adopt the improved calculation of ones.

Analytical Algorithms for the Blend Ratios by Fibre-bundle Tensile Curves Part I: Typical Tensile Curve and the Strength and Work Methods

The blend ratio and tensile properties are vital important characteristics of blended fibre bundles. Fibre-bundle tensile behaviour has been measured by means of the Sirolan-Tensor in order to derive a typical specific stress — extension curve. According to the typical tensile curve, the relationships between the blend ratio and the tensile parameters are discussed and established. Two new algorithms, so-called the strength method and the work method, have been developed for the blend-ratio estimation of blended fibre bundles. The relevant blend-ratios and calculations of the two methods are defined in detail. Also, the characteristics have been explained for every calculation and compared to each others. The experimental results show that the blend ratios estimated from the theoretical methods are high coincidence with the measured results. Meanwhile, the specific stress — extension curve of blended fibre bundles depends directly on the blend ratios of the fibre bundles.

New Contour Detection Model Working on Gray-Scale Image of Blended Yarn Cross-Section

The traditional Contour Tracing algorithm works on the binary image. It is developed that a new model called Facula Diffusion which can work directly on gray-scaled images according to the principle of human vision. The diffusion operation is controlled by four factors including approximation, closing, length-limiting, and hit-rate. Based on this model, three shape indices, i. e., dimension index, abnormity index, and fluctuation index, were put forward to describe the shape of objects. The rule of shape indices selection was discussed subsequently. Finally, the fibers in polyester/cotton blended yam are classified and the blending ratio is determined.

Blending Ratio Analysis of Akund / Cotton Blended Yarn Based on Micro Projection

A microscope method was developed for testing the blending ratio of akund/cotton blended yarns. Fiber characteristics such as diameter, longitudinal feature, and hollow structure were observed to identify akund and cotton. Therefore, the measurement of the blending ratio for akund/cotton blended yarns based on each fiber's amount, moisture regain, and metric count was available. The results show that using specimen's longitudinal section is more effective during the fiber counting than specimen's transverse section benefiting from the separation of the fibers.

Analytical Algorithms for the Blend Ratios by Fibre-bundle Tensile Curves Part Ⅲ: The Definition Method and the Relationships between the Blend Ratio and Tensile Parameters Calculated from Different Ways

The algorithms of the strength, work, modulus and percentage methods have been introduced and discussed in Part Ⅰ and Part Ⅱ of the series papers. As the following, the percentage-function calculation and the frequency-function calculation of the definition method are defined and developed in detail. Meanwhile, the procedures to find the tensile parameters are analysed experimentally and involve “ED” being the average values of the corresponding tensile parameters of each bundle tensile curve measured; “EC” being the tensile parameters obtained from the averaged experimental tensile curve; and “TC” being the parameters of the theoretical tensile curve according to the corresponding nominal blend ratio. The theoretical and experimental results indicate that the blend ratio estimated by the definition method from wool/polyester blended fibre bundles has a high correlation with the actual blend ratio though the variables to be known in this method are the most of all the methods and there exist the difficulty to solve fibre bundle tensile behaviour without fibre broken in accuracy and that there are high correlations between the EC and TC data and the tensile parameters should be calculated using the EC method rather than the ED method with the exception of the bundle initial modulus. The relationships between blend ratios and the tensile properties of blended fibre bundles can be used to select the optimum blend ratio of blended tops or yarns.

Investigation of the Effects of a Large Percentage of Dried Sludge on the Operation of a Coal-Fired Boiler

A 600 MW coal-fired boiler with a four-corner tangential combustion mode is considered here to study the combustion features and pollutant emissions at different loads for large-percentages of blending dried sludges.The influence of the over-fired air(OFA)coefficient is examined and the impact of the blending ratio on the boiler operation is explored.The results show that for low blending ratios,a slight increase in the blending ratio can improve the combustion of bituminite,whereas a further increase leads to the deterioration of the combustion of blended fuels and thus reduces the boiler efficiency.Enhancing the supporting capability of the secondary air effectively reduces the slagging degree in the bottom ash hopper and improves the burnout rate of coals.For a large-percentage blending case at full load,it is found that the OFA coefficient must be reduced appropriately,otherwise,a secondary high-temperature combustion zone can be generated in the vicinity of the furnace arches,causing high temperature slagging and superheater tube bursting.Considering the influences of combustion and pollutant emissions,the recommended OFA coefficient is 0.2.Blending dried sludge under low loads increases the flue gas temperature at the furnace exit.While reducing the flue gas temperature in the main combustion region,which is beneficial to the safe operation of the denitrification system.Increasing the blending ratio and reducing load lead to an increase in NOx concentration at the furnace exit Sludges with low nitrogen content are suggested for the practical operation of boilers.

Effects of Blending Ratio on Combustion and NO Emission Characteristics during Co-Firing of Semi-Char and Lignite in a 350 kW Pulverized Coal-Fired Furnace

The influence of the blending ratio of pyrolyzed semi-char(SC)on the ignition,NO emission and burnout characteristics of lignite co-fired with SC was investigated in a 350 kW fuel-rich/lean combustion furnace.The flame temperature and concentrations of gaseous species including O_(2),CO,and NO,were measured in detail.The results indicated that the ignition characteristics of the blended fuel worsened with increasing SC blending ratio,such as an elongated ignition standoff distance.The addition of SC to lignite delayed the appearance of a stable flame boundary,and the stable combustion zone moved down,but the final combustion stability was gradually strengthened in the later combustion stage.NO emission concentration at the primary combustion zone(PCZ)outlet was the lowest at 472.6 mg/m^(3)@6%O_(2)when the SC blending ratio was 25%.The combustion zone and reducing zone areas in PCZ were defined to evaluate the NO reduction characteristics,and quantitative analysis using a multiple linear regression model showed that heterogeneous reduction was more important than homogeneous reduction in lowering NO emissions.The Raman spectrum of the char sample indicated that the addition of lignite promoted the formation of small aromatic rings in the early ignition stage,corresponding to a higher char reactivity.The burnout ratio of pure lignite was maximal and was decreased by increasing the SC blending ratio.Synthetically,considering the ignition standoff distance,NO emission,and burnout ratio,the optimum SC blending ratio was estimated to be 25%.

Experimental Investigation for Co-Combustion Characteristics of Semi-Coke and Bituminous Coal in a 3 MWth Tangential Combustion Facility

An experimental investigation was conducted in a 3 MW pilot-scale tangential combustion facility to explore the co-combustion characteristics of bituminous coal mixed with semi-coke.The thermal gravimetric analyzer(TGA)was used to obtained fuel thermal analysis.The results presented effects of semi-coke blending ratio(BR)on average furnace temperature,ignition temperature,NO emission and combustion efficiency.The excess air coefficient in main combustion sections and outlet were fixed at 0.85 and 1.2 while BR increased from 0%to 50 wt.%.The temperature profiles of combustion decreases along the height of furnace while average furnace temperature fluctuates slightly with an increasing BR.The concentration of NO has an increasing tendency with the increasing of BR.The ignition temperature obtained from TGA measurement agreed well with experiment result.In addition,combustion efficiency was not sensitive to BR and decreased slightly with the increasing BR.

Effects of pyrolyzed semi-char blend ratio on coal combustion and pollution emission in a 0.35 MW pulverized coal-fired furnace

The effects of blend ratio on combustion and pollution emission characteristics for co-combustion of Shenmu pyrolyzed semi-char (SC), i.e., residuals of the coal pyrolysis chemical processing, and Shenhua bituminous coal (SB) were investigated in a 0.35 MW pilot-scale pulverized coal-fired furnace. The gas temperature and concentrations of gaseous species (O2, CO, CO_(2), NO_(x) and HCN) were measured in the primary combustion zone at different blend ratios. It is found that the standoff distance of ignition changes monotonically from 132 to 384 mm with the increase in pyrolyzed semi-char blend ratio. The effects on the combustion characteristics may be neglected when the blend ratio is less than 30%. Above the 30% blend ratio, the increase in blend ratio postpones ignition in the primary stage and lowers the burnout rate. With the blend ratio increasing, NO_(x) emission at the furnace exit is smallest for the 30% blend ratio and highest for the 100% SC. The NO_(x) concentration was 425 mg/m^(3) at 6% O_(2) and char burnout was 76.23% for the 45% blend ratio. The above results indicate that the change of standoff distance and NO_(x) emission were not obvious when the blend ratio of semi-char is less than 45%, and carbon burnout changed a little at all blend ratios. The goal of this study is to achieve blending combustion with a large proportion of semi-char without great changes in combustion characteristics. So, an SC blend ratio of no more than 45% can be suitable for the burning of semi-char.

Optimization of substrate ratio for beer production from finger millet and barley

Seventeen designed experiments were conducted in three steps(malting,brewing and fermentation)to produce beer from barley,finger millet and the combination of both.Effects of independent variables with three levels for each i.e.blend ratios of grains(100:0,50:50,0:100),kilning temperature(50℃,70℃,90℃)and malted grain to water ratios(1:3,1:5,1:7)were investigated on product quality.The results of the study indicated that all the independent parameters i.e.blend ratio,kilning temperature and slurry ratio affected the responses(pH,colour,bitterness and alcohol content)significantly.Optimum values of parameters,from the simultaneous optimization done using Design Expert 8.0.6.1 software,for beer production,were found to be 68:32 blend ratio,50℃ kilning temperature and 1:7 slurry ratio.The model F-value was found to be highly significant at 1% level of significance for all the responses.All the responses could be predicted by fitting the second order mathematical model and adequacy checked by R^(2).

Mathematical models for some problems in textile engineering and its corresponding discussions

Textile industry is very important to the development of Chinese industry and econ-omy.Image processing techniques are beneficial to improve the quality of cotton goods.Suitable blending ratio of yarn is good for it.It is significant to measure the blending ratio of yarn in the practice of textile engineering.Combined with results done by other scholars,this paper uses the concepts of acreage index,abnormity index and fluctuation index.Based on these morphologic indices,it is convenient to construct corresponding eigenvector and to discuss useful mathematical method for the cluster analysis during the measurement of the blending ratio.This paper also sets up some kinds of nonlin-ear optimization model for the problem.Using classical integer programming algorithm,support vector machine algorithm and genetic algorithm to the problem,we get fine results for cluster analysis.Finally,we give out another problem of image processing and have some discussions about it.