scholarly journals THEELECTROMAGNETICSHIELDINGBEHAVIOROFLAYERED KNITTED FABRIC STRUCTURES

2019 ◽  
Vol 2019 ◽  
pp. 32-35
Author(s):  
Özlem KAYACAN ◽  
Neza BAKIR ◽  
Barkın TRAŞ
Keyword(s):  
Electromagnetic Waves ◽  
Childhood Leukemia ◽  
Industrial Applications ◽  
Electromagnetic Shielding ◽  
Human Beings ◽  
Shielding Effectiveness ◽  
Technical Textiles ◽  
Fabric Structures ◽  
Electromagnetic Pollution ◽  
Risk Of Cancer

The increase in daily usage of electrical and electronic tools simplify the lives of human beings, on the other hand, they also create an enormous electromagnetic pollution. In industrial applications, electromagnetic shielding materials are used to prevent these electromagnetic signals. The studies on human health against the electromagnetic pollution was determined that the widely usage of these electronic devices increases the risk of cancer. Especially in low frequency fields, the most consistent evidence is obtained in childhood leukemia [1]. In order to reduce the damage of these electromagnetic waves, researches have been still made on the electromagnetic shielding effectiveness. Electrically conductive technical textiles are also investigated for this aim. Different textile structures such as knitted, woven, composite or coated textiles etc and also different conductive yarns are produced to prevent these harmful waves [2-5].In this study, it is aimed to investigate the electromagnetic shielding performances of conductive knitted fabrics. In order to search the efficiency of these fabrics, single jersey and interlock knitted structures are produced. By using these fabrics, two different types of double-layered fabric structures are formed and the shielding effectiveness of these structures are investigated experimentally [6}.

scholarly journals Facile Synthesis of Sandwich-Like rGO/CuS/Polypyrrole Nanoarchitectures for Efficient Electromagnetic Absorption

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 446
Author(s):  
Bing Zhang ◽  
Shaofeng Lin ◽  
Jingjing Zhang ◽  
Xiaopeng Li ◽  
Xiaodong Sun
Keyword(s):  
Electromagnetic Waves ◽  
Experimental Result ◽  
Effective Bandwidth ◽  
Human Beings ◽  
Step Method ◽  
Electromagnetic Absorption ◽  
Reduced Graphene ◽  
Electromagnetic Pollution ◽  
Harmful Effects ◽  
Minimum Reflection Loss

Currently, electromagnetic pollution management has gained much attention due to the various harmful effects on wildlife and human beings. Electromagnetic absorbers can convert energy from electromagnetic waves into thermal energy. Previous reports have demonstrated that reduced graphene oxide (rGO) makes progress in the electromagnetic absorption (EA) field. But the high value of permittivity of rGO always mismatches the impedance which results in more electromagnetic wave reflection on the surface. In this work, sandwich-like rGO/CuS/polypyrrole (PPy) nanoarchitectures have been synthesized by a facile two-step method. The experimental result has shown that a paraffin composite containing 10 wt.% of rGO/CuS/PPy could achieve an enhanced EA performance both in bandwidth and intensity. The minimum reflection loss (RL) value of −49.11 dB can be reached. Furthermore, the effective bandwidth can cover 4.88 GHz. The result shows that the as-prepared rGO/CuS/PPy nanoarchitectures will be a promising EA material.

Electromagnetic Shielding Effectiveness of Physical Property PET/Stainless Steel Composite Fabrics

2014 ◽  
Vol 910 ◽  
pp. 210-213 ◽  
Author(s):  
Jia Horng Lin ◽  
Ting An Lin ◽  
An Pang Chen ◽  
Ching Wen Lou
Keyword(s):  
Electromagnetic Waves ◽  
Physical Property ◽  
Electrical Equipment ◽  
Air Permeability ◽  
Woven Fabrics ◽  
Electromagnetic Shielding ◽  
Woven Fabric ◽  
Shielding Effectiveness ◽  
Composite Yarn ◽  
Electromagnetic Shielding Effectiveness

The electronic appliance is capable of emitting electromagnetic waves that will cause the damage of electrical equipment and influence peoples health. In this study, stain steel filament (SS filament) and 75D PET filament were used to manufacture SS/PET composite yarn The SS/PET composite yarn were made by the wrapping machine, which the core yarn is stain steel filament, wrapped yarn is 75D PET filament and the wrapping layers is varied as one and two. After that, the composite yarn is fabricated by the automatic sampling loom into composite woven fabrics. The composite SS/PET woven fabrics were under the tests of electromagnetic shielding effectiveness (EMSE) and air permeability. The test results revealed that the EMSE of the one-layer composite woven fabric is 9.5 dB at 900 MHz, but the EMSE decreases as test frequency increases. When laminating layer added to three layers, the EMSE raise up to 12.6 dB. The EMSE of composite woven fabric reached at 29.9 when the laminated angle is 45°. And the air permeability decreases as the laminate layer increases, which the thickness of sample affect air to pass through the sample.

Electromagnetic shielding effectiveness and functions of stainless steel/bamboo charcoal conductive fabrics

2013 ◽  
Vol 44 (3) ◽  
pp. 477-494 ◽  
Author(s):  
Po-Wen Hwang ◽  
An-Pang Chen ◽  
Ching-Wen Lou ◽  
Jia-Horng Lin
Keyword(s):  
Stainless Steel ◽  
Electromagnetic Waves ◽  
Experimental Testing ◽  
Cellular Phone ◽  
Far Infrared ◽  
Electromagnetic Shielding ◽  
Bamboo Charcoal ◽  
Shielding Effectiveness ◽  
Plied Yarn ◽  
Electromagnetic Shielding Effectiveness

Following technological advancements, there is a growing population of cellular phone and computer users. However, these electronic instruments cause electromagnetic waves, negatively influencing users’ health or precision instruments’ malfunction. Therefore, shielding electromagnetic wave becomes an important matter. In this study, stainless steel wires and bamboo charcoal roving are made into conductive yarn with 6 turns/cm by ring spinning machine. On a 14-gauge automatic horizontal knitting machine, the resulting yarn is then knitted into stainless steel/bamboo charcoal conductive fabrics and then evaluated for the electrical property and functions. According to experimental testing, electromagnetic shielding effectiveness (EMSE) of the fabrics increases with an increase in stainless steel content and number of lamination layers. In particular, when laminated at an angle of 0°/45°/90°/−45°/0°/45°, the fabrics have an EMSE of above 30 dB at an incident frequency between 2010 and 2445 MHz. The far infrared emissivity increases with bamboo charcoal content, reaching the maximum of 0.9 ɛ, when the fabric was made by one-cycle polyethylene terephthalate (PET)/stainless steel/bamboo charcoal plied yarn in the first feeder and four-cycle PET/bamboo charcoal plied yarn in the second feeder.

The Influence of Fabric Structures of the Woven Fabrics on Electromagnetic Shielding Effectiveness

2011 ◽  
Vol 239-242 ◽  
pp. 1994-1997 ◽  
Author(s):  
Ching Wen Lou ◽  
Yi Chang Yang ◽  
Chin Mei Lin ◽  
Ching Wen Lin ◽  
Lin Chao Chen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Electromagnetic Interference ◽  
Woven Fabrics ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Frequency Range ◽  
Fabric Structures ◽  
Electromagnetic Shielding Effectiveness

Stainless steel (SS) blended yarns with electromagnetic interference (EMI) were made into woven fabrics, after which the fabrics were evaluated with electromagnetic shielding effectiveness (EMSE). Parameters of laminated angle and the lamination number layers affected the fabrics’ EMSE differently. In addition, density of unidirectional SS yarns affected EMSE in frequency range of 200 to 500 MHz , so as the density of cross SS yarns on a frequency over 1000 MHz.

scholarly journals Electromagnetic Interference Shielding of Metal Coated Ultrathin Nonwoven Fabrics and Their Factorial Design

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 484
Author(s):  
Sundaramoorthy Palanisamy ◽  
Veronika Tunakova ◽  
Shi Hu ◽  
Tao Yang ◽  
Dana Kremenakova ◽  
...  
Keyword(s):  
Design Of Experiment ◽  
Electromagnetic Interference ◽  
Nonwoven Fabric ◽  
Electromagnetic Shielding ◽  
Material Structure ◽  
Main Role ◽  
Geometrical Shape ◽  
Human Beings ◽  
Shielding Effectiveness ◽  
Screening Design

Electromagnetic (EM) radiation is everywhere in this world and galaxy in different forms and levels. In some cases, human beings need to protect themselves from electromagnetic radiations and the same thing is also recommended for electronic devices as well. Lots of studies are there on the shielding of electromagnetic radiation interference using metals, polymers, and minerals. For protecting the human being, textile structures are playing the main role. In the textile material structure itself many types are there; each one is having its unique geometrical shape and design. In this work, the copper/nickel-coated ultrathin nonwoven fabric is prepared like a strip. The 3, 6, and 9 mm thick strips are prepared and laid at different gaps, angles, and layered to study the effect of factors on EM shielding effectiveness as per ASTM D4935-10 standard. The design of experiment has been done to analyze the three factors and three levels of the strip properties having an influence on electromagnetic shielding results. From the findings of the design of experiment (DoE) screening design, the factors are the thickness of the strips, the gap between the strips, and the strips laid angle having a statistically significant effect on electromagnetic shielding effectiveness.

Preparation and properties of graphene aerogel/cotton composite flexible fabric with electromagnetic interference (EMI) shielding function

2021 ◽  
pp. 152808372198927
Author(s):  
Peng Wang ◽  
Shuqiang Liu ◽  
Man Zhang ◽  
Gaihong Wu ◽  
Kaiwen Wang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Waterborne Polyurethane ◽  
Development Trend ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Graphene Aerogel ◽  
Emi Shielding Effectiveness ◽  
Aerogel Composite ◽  
Electromagnetic Pollution

In order to alleviate the problems caused by electromagnetic pollution and simultaneously adapt to the future development trend of flexible wearable electronic equipment, it is high time to focus on the research of light weight, flexible and efficient electromagnetic interference (EMI) shielding material. A graphene aerogel composite EMI shielding composite fabric was prepared by combining graphene aerogel with fabric through the connection of waterborne polyurethane. The influence of aerogel amount on the EMI shielding function of fabric was discussed, and the waterborne polyurethane dosage on fabric mechanics and fabric style was also investigated. The result shows the composite fabric EMI shielding effectiveness reached 28 dB when the graphene aerogel amount was 25 mL (only 0.066 mL/cm2), which has satisfied the civilian requirements (20 dB). A good adhesion fastness between graphene and cotton fabric was obtained and the mechanical strength was also improved when the content of waterborne polyurethane was 20 mL. Graphene aerogel electromagnetic shielding composite fabric with good electromagnetic shielding performance and less consumption of nano carbon materials will have a good industrial application prospect.

A model for predicting electromagnetic shielding effectiveness of conductive fiber plain fabric

2020 ◽  
pp. 152808372092935
Author(s):  
Jianjun Yin ◽  
Wensuo Ma ◽  
Zhaohua Huang ◽  
Kui Liu ◽  
Zhuang Leng
Keyword(s):  
Electromagnetic Waves ◽  
Weighted Average ◽  
Transverse Magnetic ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Conductive Fiber ◽  
Transmission Coefficients ◽  
Plain Fabric ◽  
Fabric Surface ◽  
Electromagnetic Shielding Effectiveness

Conductive fiber plain fabric can be used for manufacturing electromagnetic protective products, due to the capacity of electromagnetic shielding effectiveness and deformability. A model was established to predict the shielding effectiveness of conductive fiber plain fabric. The curved surface of fabric can be decomposed into countless ideal planes. The vertical incidence of electromagnetic waves on plain fabric surface can be regarded as the oblique incidence on the ideal plane. The transmission coefficients of transverse electric and transverse magnetic polarized waves were different in each point of fabric surface through the surface equation. The weight factor was supposed as the value of small area at each incident point, and the weighted average of transmission coefficients was deduced. The results showed that, the values of shielding effectiveness increased with the decrease of the pitch of conductive fiber plain fabric and increased with the increase of frequency in the range of 0.1–2 GHz. The trends of theoretical prediction values were consistent with the simulation and experimental values, which proved the rationality of the model.

The effects of fabric lamination angle and ply number on electromagnetic shielding effectiveness of weft knitted fabric-reinforced polypropylene composites

2014 ◽  
Vol 21 (1) ◽  
pp. 129-135 ◽  
Author(s):  
Devrim Soyaslan ◽  
Özer Göktepe ◽  
Selçuk Çömlekçi
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Copper Wire ◽  
Industrial Applications ◽  
Electromagnetic Shielding ◽  
Knitted Fabric ◽  
Shielding Effectiveness ◽  
Polypropylene Composites ◽  
Weft Knitted Fabric ◽  
Electromagnetic Shielding Effectiveness

AbstractIn this study, it was aimed to investigate the effects of fabric lamination angle and fabric ply number on electromagnetic shielding effectiveness (EMSE) of weft knitted fabric-reinforced polypropylene composites. Knitted fabric-reinforced composites are composed of aramid yarn, polypropylene yarn, and copper wire. Polypropylene is the matrix phase and the aramid yarn and copper wires are the reinforcement phase of the composite materials. It was achieved to form 1.5 to 3 mm thickness composites. The composites have nearly 20–50 dB electromagnetic shielding values. To form the knitted fabrics, 7G semiautomatic flat knitting machine was used. The composites were formed by a laboratory-type hot press. EMSE of composites were tested by using ASTM D 4935 coaxial test fixture in 27–3000 MHz frequency band. Lamination angle and ply number parameters were examined related to EMSE of structures. For this study, three different structures were knitted and named as plain knit, 1×1 rib knit, and half cardigan knit. To determine the effect of lamination angle of composites on electromagnetic shielding performance, the composites were produced in two different lamination angles as 0°/90°/0°/90° and 0°/45°/0°/45°. To determine the effect of fabric ply number of composites on electromagnetic shielding performance, the composites were produced in two and four plies. It was observed that the fabric ply number and lamination angle does not affect the EMSE of composite materials very much. It was determined that weft knitted reinforced composite structures have appropriate and high EMSE values for electromagnetic applications. This knitted fabric-reinforced polypropylene composites are flexible and suitable for other industrial applications as civil engineering, aerospace, etc.

scholarly journals Conducting Polymeric Composites Based on Intrinsically Conducting Polymers as Electromagnetic Interference Shielding/Microwave Absorbing Materials—A Review

2021 ◽  
Vol 5 (7) ◽  
pp. 173
Author(s):  
Bluma Guenther Soares ◽  
Guilherme M. O. Barra ◽  
Tamara Indrusiak
Keyword(s):  
Conducting Polymers ◽  
Electromagnetic Interference ◽  
Electromagnetic Shielding ◽  
Human Beings ◽  
Shielding Effectiveness ◽  
Electromagnetic Interference Shielding ◽  
Preparation Methods ◽  
Microwave Absorbing Materials ◽  
Microwave Absorbing ◽  
Intrinsically Conducting Polymers

The development of sophisticated telecommunication equipment and other electro-electronic devices resulted in a kind of electromagnetic pollution that affects the performance of other equipment as well as the health of human beings. Intrinsically conducting polymers (ICP), mainly polyaniline and polypyrrole, have been considered as promising candidates for applications in efficient electromagnetic interference shielding (EMI) due to their ease of preparation, light weight, good conductivity and corrosion resistance. One of the important advantages of these materials is the capability to interact with the EM radiation through both absorption and reflection mechanisms thus enlarging the field of application. In this context, this review article describes a recent overview of the existing methods to produce intrinsically conducting polymers and their blends for electromagnetic shielding application. Additionally, it highlights the relationship between preparation methods reported in the literature with the structure and properties, such as electrical conductivity, electromagnetic shielding effectiveness (EMI SE), complex permittivity and permeability of these materials. Furthermore, a brief theory related to the electromagnetic mechanism and techniques for measuring the microwave absorbing properties are also discussed.

Investigation of the Electromagnetic Shielding Effectiveness of Carded and Needle Bonded Nonwoven Fabrics Produced at Different Ratios with Conductive Steel Fibers

2015 ◽  
Vol 10 (1) ◽  
pp. 155892501501000
Author(s):  
Mustafa Sabri Özen
Keyword(s):  
Stainless Steel ◽  
Electromagnetic Waves ◽  
Nonwoven Fabric ◽  
Electromagnetic Shielding ◽  
Steel Fibers ◽  
Shielding Effectiveness ◽  
Nonwoven Fabrics ◽  
Needle Punching ◽  
Stainless Steel Fiber ◽  
Electromagnetic Shielding Effectiveness

The number of electrical and electronic devices in our daily life has increased. The devices produce electromagnetic waves which harm human and environments. In recent years, there has been an increasing interest in the reduction and control of electromagnetic waves. The paper focuses on shielding of electromagnetic waves of nonwoven fabrics produced with needle punching technology from conductive stainless steel fibers. The needle punched nonwoven fabrics were produced with carding and needle punching technology by blending stainless steel fibers and normal staple polyester fibers at different ratios for electromagnetic shielding applications. The electromagnetic shielding effectiveness of the nonwoven fabrics with conductive stainless steel fibers was tested. After blending of stainless steel fibers and normal polyester fibers, the webs were formed by a wool-type carding machine and the after web folding operation, the webs were bonded by needle punching at constant working parameters. During production, the needle punch densities per cm2 and needle penetration depth per mm were kept constant. Bulky needle punched nonwoven fabrics with low needling density were produced. The main objective of our research was to develop the nonwoven fabric for shielding against electromagnetic waves. In addition, the effect of the stainless steel fiber ratio used in the needle punched nonwoven fabrics on electromagnetic shielding effectiveness was investigated. After production, the thicknesses of the needle punched nonwoven fabrics were tested. The electromagnetic shielding effectiveness, reflection and absorption values of the needle punched nonwoven fabric samples were measured at the frequency range of 15-3000MHz and presented in table and graphics. As the ratio of stainless steel fibers used in the nonwoven fabric increased, Electromagnetic shielding effectiveness values (EMSE) were increased in a linear manner and obtained results were discussed. It was found that the electromagnetic waves were shielded about 90% at high frequencies, 85% at medium frequencies, and 80% at low frequencies by needle punched nonwoven fabric with 5% conductive stainless steel fiber. The EMSE values such as 20dB, 25dB and 45dB were obtained at low frequency ranges (0–300MHz and 25dB, medium frequency ranges, 300-1200MHz and 45dB, and high frequency ranges, 1200-3000MHz) with the needle punched nonwoven fabric containing 25% conductive stainless steel fiber.

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