scholarly journals Structure and breathability of silk/cashmere interwoven fabrics based on fractal theory

2020 ◽  
Vol 15 ◽  
pp. 155892502097930
Author(s):  
Ying Chen ◽  
Lifan Mei ◽  
Qiuyu Li
Keyword(s):  
Fractal Dimension ◽  
Structural Parameters ◽  
Fractal Theory ◽  
Air Permeability ◽  
Water Soluble ◽  
Weft Yarn ◽  
Warp Yarn ◽  
Moisture Permeability ◽  
And Performance ◽  
The Relationship

The fractal weave has a different appearance from the traditional weaves, and the fabric performances such as air and moisture comfort have not been studied. The relationship between the fabric structure and performance of the fractal weaves is not yet clear. In this paper, the corresponding fractal weaves were generated based on the fractal theory, and the corresponding fabrics were woven using raw silk as the warp yarn and cashmere/water-soluble vinylon as the weft yarn. The structural parameters, air permeability and moisture permeability were tested. The results show that fabric moisture permeability are not closely related with the three weave parameters of fractal dimension, average float length and weave coefficient. Its conduction mechanism is different from air permeability. The average floating length, fractal dimension, and its parameter combinations have a good fitting relationship with air permeability, and the polynomial fitting R2 can reach to 0.99938. The fitting formula 8 has guiding significance for the design of fabrics with certain air permeability requirements.

The influence of high temperature treatment on morphology and performance of superfine glass fiber felts

2020 ◽  
Vol 90 (19-20) ◽  
pp. 2292-2303
Author(s):  
Feiyan Wang ◽  
Jianyong Yu ◽  
Xunmei Liang ◽  
Shide Lu ◽  
Chunfeng Zhao ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Glass Fiber ◽  
Pore Size ◽  
Fractal Dimensions ◽  
Air Permeability ◽  
Temperature Treatment ◽  
Heat Treatments ◽  
High Temperature Treatment ◽  
And Performance ◽  
The Relationship

This article presents an investigation on effects of heat treatments in the range 400–700℃ on morphology, fractal dimension, pore size distribution, and air permeability of superfine glass fiber felts. During the heat treatments, the released residual stress, thermal decomposition, and thermal contraction make fibers bend to different degrees, corresponding with different fractal dimensions. The felt pores are formed by the random interlacing of fibers, varying with the different bending degree of fibers, which results in an influence on the air permeability of the felt. The results show that there was no visible change in the morphology of the heated felt at 400–550℃. However, the treatment at 600℃ could cause the breakage of some fibers, and above 650℃ the damage of felts. The fractal dimension of heated felt decreased at 400 and 450℃, but then increased above 500℃. The lowest fractal dimension was 1.8827 at 450℃, and the highest was 1.9666 at 600℃. Besides, the pores tend to distribute in a smaller size and a narrower scale under high temperatures, resulting in a decrease in the air permeability. However, the air permeability had the same variation trend with fractal dimension at 400 and 450℃, but opposite above 500℃. The relationship among them was verified by comparing the experimental and theoretical results. At 600℃, the mean pore size and the air permeability reduced by 16% and 31%, respectively.

Variation of Poisson’s ratio of fabrics woven with helical composite auxetic weft yarns in relation to fabric structural parameters

2019 ◽  
Vol 50 (2) ◽  
pp. 149-169
Author(s):  
Asal Lolaki ◽  
Mohsen Shanbeh
Keyword(s):  
Poisson’S Ratio ◽  
Structural Parameters ◽  
Processing Technique ◽  
Poisson's Ratio ◽  
Image Processing Technique ◽  
Weft Yarn ◽  
Warp Yarn ◽  
Dimensional Changes ◽  
Weft Direction ◽  
Yarn Count

Auxetic textiles are defined as textiles with negative Poisson’s ratio. These textiles possess unique properties that render them suitable for special applications. This work aims to investigate the effect of fabric structural parameters such as thread densities, weave design and warp yarn count. Thus, 30 fabric samples were woven at 3 weft and 2 warp densities, respectively. Two warp counts and three weave designs of plain, basket 3/3 and weft-backed satin 6 were used. The samples were uniaxially loaded in weft direction and dimensional changes at various strains levels were evaluated. The evaluation was carried out using the image processing technique based on MATLAB software. The weft yarns used were found to exhibit auxetic behavior at the whole spectrum of the strain level used. The least weft yarn Poisson’s ratio was found to be −0.9. It was established that in general the fabric samples exhibit auxetic effect within the stated range of strain. Additionally, it was concluded that while fabric thread densities together with warp count influence the minimum fabric Poisson's ratio, auxetic behavior of the samples is not dependent on weave design alone. Rather, it was illustrated that the combined effect of weave design in association with stated structural parameters on auxetic feature cannot be ignored.

EFFECT OF FRACTAL FRACTURES ON PERMEABILITY IN THREE-DIMENSIONAL DIGITAL ROCKS

Fractals ◽  
2019 ◽  
Vol 27 (01) ◽  
pp. 1940015 ◽  
Author(s):  
WEIFENG LV ◽  
GUOLIANG YAN ◽  
YONGDONG LIU ◽  
XUEFENG LIU ◽  
DONGXING DU ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Fractal Theory ◽  
Fractured Reservoirs ◽  
Three Dimensional ◽  
Absolute Permeability ◽  
Fracture Aperture ◽  
Fracture Networks ◽  
Discrete Fracture Networks ◽  
Discrete Fracture ◽  
The Relationship

The fracture has great impact on the flow behavior in fractured reservoirs. Fracture traces are usually self-similar and scale-independent, which makes the fractal theory become a powerful tool to characterize fracture. To obtain three-dimensional (3D) digital rocks reflecting the properties of fractured reservoirs, we first generate discrete fracture networks by stochastic modeling based on the fractal theory. These fracture networks are then added to the existing digital rocks of rock matrixes. We combine two low-permeable cores as rock matrixes with a group of discrete fracture networks with fractal characteristics. Various types of fractured digital rocks are obtained by adjusting different fracture parameters. Pore network models are extracted from the 3D fractured digital rock. Then the permeability is predicted by Darcy law to investigate the impacts of fracture properties to the absolute permeability. The permeability of fractured rock is subject to exponential increases with fracture aperture. The relationship between the permeability and the fractal dimension of fracture centers is exponential, as well as the relationship between permeability and the fractal dimension of fracture lengths.

scholarly journals Review about the Application of Fractal Theory in the Research of Packaging Materials

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 860
Author(s):  
Qingshan Duan ◽  
Jiejie An ◽  
Hanling Mao ◽  
Dongwu Liang ◽  
Hao Li ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Fractal Analysis ◽  
Fractal Theory ◽  
Inorganic Materials ◽  
Packaging Materials ◽  
Analysis Method ◽  
Characteristic Parameters ◽  
Fractal Characteristic ◽  
Fractal Characteristics ◽  
The Relationship

The work is intended to summarize the recent progress in the work of fractal theory in packaging material to provide important insights into applied research on fractal in packaging materials. The fractal analysis methods employed for inorganic materials such as metal alloys and ceramics, polymers, and their composites are reviewed from the aspects of fractal feature extraction and fractal dimension calculation methods. Through the fractal dimension of packaging materials and the fractal in their preparation process, the relationship between the fractal characteristic parameters and the properties of packaging materials is discussed. The fractal analysis method can qualitatively and quantitatively characterize the fractal characteristics, microstructure, and properties of a large number of various types of packaging materials. The method of using fractal theory to probe the preparation and properties of packaging materials is universal; the relationship between the properties of packaging materials and fractal dimension will be a critical trend of fractal theory in the research on properties of packaging materials.

Study about Characteristics of Cement Paste on Fractal Theory

2013 ◽  
Vol 423-426 ◽  
pp. 1051-1054
Author(s):  
Tian Yang Zhai
Keyword(s):  
Compressive Strength ◽  
Fractal Dimension ◽  
Cement Paste ◽  
Permeability Coefficient ◽  
Fractal Theory ◽  
Fractal Model ◽  
Concrete Compressive Strength ◽  
Internal Pore Structure ◽  
The Relationship ◽  
Internal Pore

A fractal model to simulate cement paste internal pore structure, and on this basis deduce that fractal dimension is D and the corresponding pore is r, the relationship between porosity is P. MIP was measured test. Then calculated the different ages of the fractal dimension of cement and concrete compressive strength, tensile strength and permeability coefficient. The results showed that: compressive strength, permeability and fractal dimension has a good correlation. Whey in cement in the process of hydration of cement products continue to fill the pores, making the compressive strength increased 70%, permeability is declining.

Particles Gradation Optimization of Blasting Rockfill Based on Fractal Theory

2011 ◽  
Vol 366 ◽  
pp. 469-473 ◽  
Author(s):  
Sheng Zhu ◽  
Yan Ming Feng ◽  
Shu Rong Feng ◽  
Wu Yi Chen
Keyword(s):  
Fractal Dimension ◽  
Test Data ◽  
Fractal Theory ◽  
Average Diameter ◽  
Optimization Method ◽  
Dry Density ◽  
Rock Blasting ◽  
Rockfill Dam ◽  
Under Construction ◽  
The Relationship

Based on fractal theory, used the index of rockfill compaction characteristics(granularity fractal dimension) which conforms to Talbot curve distribution, combined with blasting schemes and rolling test data of several domestic rockfill dams, the relationship is established between compacted rockfill’s dry density and rock blasting parameters by rockfill granularity fractal dimension and its average diameter, and that provided the basis for rockfill particle grading optimization method. The method is applied by rockfill of JIANGPINGHE dam under construction, and the results show that this method can well reflect the intrinsic relation between rock blasting and rockfill compaction, which can be applied to particle grading design of rockfill dam.

Pilot Study of PET/Bamboo Charcoal Warp-Knitted Fabric

2012 ◽  
Vol 184-185 ◽  
pp. 1090-1093 ◽  
Author(s):  
Jia Horng Lin ◽  
Ching Wen Lin ◽  
Chin Mei Lin ◽  
Yi Chang Yang ◽  
Ting Ting Li ◽  
...  
Keyword(s):  
Far Infrared ◽  
Air Permeability ◽  
Weft Yarn ◽  
Knitted Fabric ◽  
Bamboo Charcoal ◽  
Health It ◽  
Warp Yarn ◽  
Knitted Fabrics ◽  
Far Infrared Ray ◽  
Warp Knitted Fabric

In recent years, as improvement of human living life, people begin to focus on themselves health. It is certain that bamboo charcoal has many properties, including water purification, deodorization, anion release and far-infrared ray radiation. This study aims to prepare PET/BC warp-knitted fabric composed of polyester yarn (PET) as warp yarn and bamboo charcoal polyamine yarn (BC) as weft yarn using Velcro Crochet Machine. Afterwards, air permeability, elastic resilience and far-infrared ray emissivity of resulting knitted fabric were discussed by changing weft yarn type. Result shows that, for knitted fabrics, weft yarn type cannot affect the elastic resilience; yet PET weft yarn makes air permeability decreasing.

scholarly journals The Evolutionary Characteristics of Reservoir Microstructure under Long-Term Waterflooding Development and Its Fractal Description

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Fengjiao Wang ◽  
Xu Wang ◽  
Yikun Liu ◽  
Qingjun Deng ◽  
Jianjun Xu ◽  
...  
Keyword(s):  
Pore Structure ◽  
Physical Simulation ◽  
Structural Parameters ◽  
Fractal Theory ◽  
Evolution Model ◽  
Structure Evolution ◽  
Before And After ◽  
Water Cut ◽  
The Relationship

Generally, long-term waterflooding development often leads to the change of reservoir pore and clay mineral composition, which results in the change of permeability and wettability. In order to explore the relationship between core micropore structure and water cut, based on physical simulation experiments and fractal theory, we proposed a fractal evolutionary model to describe the evolution characteristics of microstructure of long-term water driving reservoirs. In this paper, core pore structure by SEM was first conducted to analyze the change of core pore structure before and after waterflooding under the conditions of magnification of 200 times, 800 times, and 2000 times, respectively. Then, conventional and constant rate mercury injection tests were combined to perform the comparative analysis of core structural parameters before and after waterflooding. Finally, a micropore-throat structure evolution model of core was established. Research shows that the connectivity of larger pores becomes better after long-term water driving, the degree of heterogeneity weakens, and the micro heterogeneity of small pores becomes stronger and stronger. The throat characteristics change in a complex manner, the radius tends to increase, and the sorting becomes better, while the connectivity of small throat changes complex. In general, the heterogeneity of throat increases with the time of water injection in reservoirs with low porosity and permeability. On the basis of fractal theory and variation characteristics of rock pore structure in water driving reservoirs, we have established a micropore-throat structure evolution model of core pore-throat characteristics. This fractal evolution model quantitatively characterized the complexity and evolution law of pore structure and clarified the relationship between fractal dimension of core pore structure and water cut under different stages of water driving.

The Numerical Simulation and Optimal Design of Nozzle Jet for Gas-Fluid Two Phase Flow

2011 ◽  
Vol 291-294 ◽  
pp. 2403-2406
Author(s):  
Yan Min Li ◽  
Fei Ma
Keyword(s):  
Optimal Design ◽  
Two Phase Flow ◽  
Structural Parameters ◽  
Performance Testing ◽  
Fluid Phase ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Distributions ◽  
And Performance ◽  
The Relationship

Taking a nozzle jet for gas-fluid phase flow as a research object, the influences of the main structural parameters on the vacuum in the internal suction volume are analyzed. Utilizing the software FLUENT to simulate the gas-liquid two-phase flow in nozzle jet with different structural parameters, the pressure distributions are obtained and the relationship between the structural parameters and the vacuum in the suction volume is concerned. The results show that the vacuum in the suction volume of jet reaches the maximum when these structural parameters are some certain values. The research is helpful for the optimal design and performance testing of nozzle jets.

Relationship between Fractal Dimension and Structure of Nonwovens

2013 ◽  
Vol 750-752 ◽  
pp. 1176-1179
Author(s):  
Shu Yang
Keyword(s):  
Fractal Dimension ◽  
Structural Parameters ◽  
Average Density ◽  
Traditional Methods ◽  
Pore Characteristics ◽  
Fractal Approach ◽  
Basic Parameters ◽  
The Relationship

The structures of nonwovens are so nonlinear and out-of-order that traditional methods can hardly measure it. There exist several basic parameters to characterize it, such as thickness, grammage, average density and pore characteristics etc.. It is necessary to find one integrated parameter to characterize nonwovens, and fractal approach seems to be a useful tool. In this paper, the fractal dimension is implemented to describe the structure of nonwovens. And then the relationship between the fractal dimension and several basic structural parameters are built up.

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