Electroless plating process for the manufacture of radiation protection suits for pregnant woman: Effect of bending on its electromagnetic shielding performance

2022 ◽  
pp. 152808372110682
Author(s):  
Chengmei Gui ◽  
Di Sun ◽  
Wenya Liu ◽  
Haodong Ma ◽  
Zhenming Chen ◽  
...  
Keyword(s):  
Pregnant Woman ◽  
Radiation Protection ◽  
Noble Metals ◽  
Low Cost ◽  
Fiber Surface ◽  
Electroless Nickel ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Blend Fiber ◽  
Negative Effect

Multi-ion fabrics (especially silver ion fabrics) have special advantages as electromagnetic radiation, but the use of noble metals enhances its cost. Electroless nickel plating (EP-Ni) has great potential application in fabricating low-cost metallized material. Here, EP-Ni on pure cotton surface to fabricate radiation protection suits for pregnant woman was established to replace traditional protection suits with silver film. The active groups on the cotton/polyester blend fiber surface could absorb tin and palladium ions, acting as catalytic centers, which can catalyze the reduction of Ni2+ in the plating solution. Ni particle with (111) crystal plane preferential oriented crystal structure deposited on cotton surface with a coarse microstructure. The Ni deposited amount is about 19%. The fabricated material exhibited a shielding effectiveness of 29.5 dB. Studies also shown that bending has no negative effect on crystallinity and electrical property. But more bending times could lead to crack, which would decline electromagnetic shielding performance by 24%.

Fashion clothing with electromagnetic radiation protection: aesthetic properties and performance

2020 ◽  
Vol 90 (21-22) ◽  
pp. 2504-2521
Author(s):  
Veronika Tunakova ◽  
Maros Tunak ◽  
Pavla Tesinova ◽  
Marie Seidlova ◽  
Jiri Prochazka
Keyword(s):  
Electromagnetic Radiation ◽  
Radiation Protection ◽  
Electromagnetic Shielding ◽  
Woven Fabric ◽  
Digital Printing ◽  
Color Fastness ◽  
Shielding Effectiveness ◽  
Metal Fiber ◽  
Electrically Conductive ◽  
Negative Effect

At present, much attention is focused on developing clothing fabrics with advanced functionality without compromising their visual, mechanical, or comfort properties. A fabric’s ability to prevent the penetration of electromagnetic radiation is an interesting added feature. In the published literature, there are many references describing the development and investigation of electromagnetic shielding textile structures using different electrically conductive additives. However, little attention has been given to the aesthetic and comfort properties of these special fabrics. Moreover, the availability of everyday fashion containing electromagnetic radiation protection is very limited. For this study, woven fabric made from a mixture of traditional fibers and extremely thin discrete stainless steel fibers developed in the authors’ previous research was used as a substrate. The fabric was digitally printed to provide an interesting design effect suitable for use in clothing and for making clothes for everyday wear. The main objective of this work is to determine whether digital printing is a suitable tool for changing the color and pattern of this metal fiber-containing fabric. The individual goals are (a) to examine the fabric’s color fastness to washing and (b) to investigate whether the surface modification of the fabric adversely affects its functionality. Results show that it is possible to change the color and pattern of metal fiber-containing fabric by digital printing easily, whereas the associated decrease of porosity causes an increase of this special fabric functionality. The electromagnetic shielding effectiveness of the fabric after printing is around 33 dB for frequency 1.5 GHz. However, washing has a negative effect, causing both the electromagnetic shielding ability decrease (to 27 dB for frequency 1.5 GHz after 20 washing and drying cycles) and color fading (the color fastness grade is around 1–2 after 20 washing and drying cycles). Furthermore, the basic transport properties of printed electrically conductive fabric are compared with those of fabric made from traditional material and positive results are found. The incidence of pilling after washing is also evaluated, whereas the first pills are observed after the eighth washing and drying cycle. Finally, clothing prototypes that could be prepared from printed fabric are presented.

Comparison of Electroless Nickel-Plated Wood-Based EMI Composite with Two Methods of Pd Activation

2011 ◽  
Vol 183-185 ◽  
pp. 1563-1567 ◽  
Author(s):  
Hai Bing Liu ◽  
Li Juan Wang
Keyword(s):  
Electroless Nickel ◽  
Xrd Analysis ◽  
Electromagnetic Shielding ◽  
Surface Resistivity ◽  
The Other ◽  
Shielding Effectiveness ◽  
P Content ◽  
Electroless Ni ◽  
Electromagnetic Shielding Effectiveness

In this paper we prepared electroless Ni-plated wood veneers using two Pa activation methods. One is the traditional Pa colloid activation and the other uses Pa2+ions. SEM-EDS results indicated that the coatings were continuous, uniform and compact with a P content of lower than 4 wt.%. XRD analysis showed that the coatings were crystalline, which was related to the low P content. The plated wood veneers exhibit good electro-conductivity with surface resistivity of lower than 0.3 Ω cm-2and higher electromagnetic shielding effectiveness of over 60 dB in frequencies from 10 MHz to 1.5 GHz.

scholarly journals FABRICS FOR BUILDTECH ELECTROMAGNETIC SHIELDS BASED ON MAGNETRON SPUTTERING DEPOSITION

2019 ◽  
Vol 2019 ◽  
pp. 63-67
Author(s):  
Lilioara SURDU ◽  
Cristian STANCU ◽  
Emilia VISILEANU ◽  
Ion Răzvan RĂDULESCU ◽  
Mihai BADIC ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Fiber Surface ◽  
Woven Fabrics ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Sem Images ◽  
Sputtering Deposition ◽  
Linear Resistance ◽  
Coated Fabrics ◽  
Conductive Properties

Electromagnetic radiation may cause interference for the proper functioning of electronic equipment and risks for human’s health. Protection against the hazards of EM radiation on various frequencies may be achieved by flexible textile fabrics with electrical conductive properties. A novel technology for imparting conductive properties to fabrics is utilizing magnetron sputtering of metallic thin films. This research focuses on plasma coated fabrics with three types of metallic layers: Nick el, Chrome and Titanium. PES woven fabrics of 88 g/m2 were coated by plasma magnetron sputtering with these three types of metals. Coating was performed on both sides of the fabric with a thickness of 400 nm. SEM images provedmetal deposition on the fiber surface, while atomic absorption tests showed the content of deposited metal. Linear resistance of coated fabrics was measured with Ohmmeter for a preliminary check of electric conductivity of the achieved fabrics. Electromagnetic shielding effectiveness tests showed a slight increase of EMSE above the noise level in the frequency range of 100-1000 MHz, of 2- 3 dB. The research studies will continue to improve shielding effectiveness of plasma coated fabrics for electromagnetic shielding

Improving the electromagnetic shielding of nickel/polyaniline coated polytrimethylene-terephthalate knitted fabric by optimizing the electroless plating conditions

2016 ◽  
Vol 87 (8) ◽  
pp. 902-912 ◽  
Author(s):  
Hu Jiyong ◽  
Li Guohao ◽  
Shi Junhui ◽  
Yang Xudong ◽  
Ding Xin
Keyword(s):  
Electroless Plating ◽  
Electromagnetic Interference ◽  
Electronic Devices ◽  
Electroless Nickel ◽  
Electromagnetic Shielding ◽  
Health Issues ◽  
Shielding Effectiveness ◽  
Frequency Range ◽  
Electromagnetic Shielding Effectiveness

To solve electromagnetic interference of electronic devices and health issues by the expansion of the electronic industry and the extensive use of electronic equipment, flexible and stretchable conductive elastic textiles are beneficial. This study prepared conductive Ni/polyaniline (PANi)/polytrimethylene-terephthalate (PTT) composite fabric by in situ chemical polymerization and electroless nickel plating. Their direct current electrical resistance and the shielding efficiency energy were tested. Furthermore, the effect of electroless plating conditions was investigated on surface resistivity and electromagnetic shielding effectiveness (EMSE) of the composite fabric, and the correlation between electrical resistivity and EMSE was explored. The results show that the shielding efficiency energy of Ni/PANi/PTT composite fabric optimized can reach more than 40 dB and at a given frequency it has an inverse parabolic relation with the electroless plating conditions. In addition, when the electroless plating conditions is the determinant, the SE has little change in the electromagnetic wave frequency, especially in the frequency range of 600 MHz or more. It is concluded that the EMSE of the Ni/PANi/PTT conductive fabrics could be tailored by modifying the chemical reagent contents in the electroless plating solution.

Can Virtual Replace In-person Coaching? Experimental Evidence on Teacher Professional Development and Student Learning in South Africa

2021 ◽  
Author(s):  
Jacobus Cilliers ◽  
Brahm Fleisch ◽  
Janeli Kotzé ◽  
Nompumelelo Mohohlwane ◽  
Stephen Taylor ◽  
...  
Keyword(s):  
Professional Development ◽  
South Africa ◽  
Language Proficiency ◽  
Oral Language ◽  
Low Cost ◽  
Reading Proficiency ◽  
Home Language ◽  
Oral Language Proficiency ◽  
Virtual Coaching ◽  
Negative Effect

Virtual communication holds the promise of enabling low-cost professional development at scale, but the benefits of in-person interaction might be difficult to replicate. We report on an experiment in South Africa comparing on-site with virtual coaching of public primary school teachers. After three years, on-site coaching improved students' English oral language and reading proficiency (0.31 and 0.13 SD, respectively). Virtual coaching had a smaller impact on English oral language proficiency (0.12 SD), no impact on English reading proficiency, and an unintended negative effect on home language literacy. Classroom observations show that on-site coaching improved teaching practices, and virtual coaching led to larger crowding-out of home language teaching time. Implementation and survey data suggest technology itself was not a barrier to implementation, but rather that in-person contact enabled more accountability and support.

scholarly journals Optically transparent and very thin structure against electromagnetic pulse (EMP) using metal mesh and saltwater for shielding windows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Duy Tung Phan ◽  
Chang Won Jung
Keyword(s):  
Electromagnetic Pulse ◽  
Low Cost ◽  
High Energy ◽  
Metal Plate ◽  
Optical Transparency ◽  
Shielding Effectiveness ◽  
Concrete Wall ◽  
Metal Mesh ◽  
Wide Range ◽  
Optically Transparent

AbstractAn electromagnetic pulse (EMP) with high energy can damage electronic equipment instantly within a wide range of thousands of kilometers. Generally, a metal plate placed inside a thick concrete wall is used against an EMP, but it is not suitable for an EMP shielding window, which requires not only strong shielding effectiveness (SE) but also optical transparency (OT). In this paper, we propose a very thin and optically transparent structure with excellent SE for EMP shielding window application. The proposed structure consists of a saltwater layer held between two glass substrates and two metal mesh layers on the outside of the glass, with a total thickness of less than 1.5 cm. The SE and OT of the structure are above 80 dB and 45%, respectively, which not only meet the requirement of EMP shielding for military purposes but also retain the procedure of good observation. Moreover, the OT of the structure can be significantly improved using only one metal mesh film (MMF) layer, while the SE is still maintained high to satisfy the required SE for home applicants. With the major advantages of low cost, optical transparency, strong SE, and flexible performance, the proposed structure can be considered a good solution for transparent EMP shielding windows.

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