E-Textiles have gained enormous attention due to their specific characteristics in various non-conventional applications such as electromagnetic shielding materials. With the advent of various high frequency-driven devices, the need to restrict the non-ionizing radiations from their undesired effects became imperative. Due to the ease of production, better electrical conductivity and durability, the conductive hybrid cover yarns with continuous metallic filaments have earned its place as the most convenient form of yarns to develop E-textiles. However, controlling the amount of conducting material in yarns poses a challenge as the increase in size of the metallic filaments are associated with reduced electromagnetic shielding effectiveness due to increased stiffness of yarns, which resists in proper interlacement and hence causes openness in fabrics. The proposed design of conductive hybrid cover yarns is proven to have better tensile properties and modulus, therefore this design is more suitable to produced fabrics with higher cover factors. The amount of conducting material in the proposed design increased significantly without changing the size of the continuous filaments. Moreover, 99.9% shielding effectiveness is achieved with this increased metal content in fabrics in S-band and partly C-band microwave frequencies.
material where negative permittivity and negative permeability are tailored to have negative refractive index property in some certain frequencies. The negative refractive index property usually occurs where the permittivity and permeability are found to be negative. D. R. Smith and his colleagues constructed such composite material by utilizing repeated metallic wires and split-ring resonators to have negative permittivity and permeability. They claimed that negative permittivity can be achieved by repeated metallic wire inclusion and negative permeability can be obtained by numerous magnetic structures like π-shape, S-shape, Z-shape and other interesting shapes [3][4][5][6]. It is well known that metamaterials are formed by small unit cells that are arranged in a periodic form and the characteristics of each individual unit cell are very important for the overall material's performance. However, recently, in some specific applications like, antenna design or filter design, utilization of single metamaterial unit cell is one of the promising approaches instead of bulk metamaterial or array of unit cells [7][8][9]. Besides this, it is being applied in specific absorption rate (SAR) reduction in human head, cloaking an object electromagnetically, designing polarizer or absorber and many other interesting applications [10][11][12]. According to the applications, different types of alphabetic metamaterial unit cells with NRI property were proposed in the literature but not all of these designs show negative refractive index property in the C-and X-band ranges with wide bandwidth. For example, Chang-Chun et al. [3] demonstrated a π-shaped negative refractive index metamaterial but it works in the X-band only. Hayet Benosman et al. [4], presented an 'S' shaped NRI metamaterial that operates in the K u -band only. Abdullah Dhouibi et al. proposed a 'Z' shaped metamaterial for C-band only in [5] but it was not showing NRI property.Abstract A new wideband negative refractive index (NRI) metamaterial for dual-band operation is introduced in this study. Initially, a bare-H-shaped resonator was designed over the FR-4 substrate material. The refractive index curve for the unit cell, displays more than 3-GHz negative real peak from C-band to some portion of X-band. The proposed design also displays NRI property in the same frequency bands with wider bandwidth, when the Rogers RT 3010 substrate material was employed instead of FR-4 substrate material.
This paper presents the rate of optical absorption in the visible wavelength region for low concentration of ethanol in water. Ethanol absorption rate was measured in neutral, acidic and alkaline medium of potassium permanganate (KMnO4) dye. The absorption rate was measured for 0.01% to 1% ethanol. This non-contact optical system employs tungsten halogen light source and spectrometer from Ocean Optics. This method demonstrates a sensitivity of more than 0.01%; fast detection speed of 27s; and has potential for in situ measurement.
This paper mainly discusses on the effectiveness of multiple plain-woven fabric towards electromagnetic shielding (EMS). The measurement includes the effect of fabric distance from the transmitter antennas in the shielded enclosure test. The conductive fabric consists of copper cover hybrid yarns produced using hollow spindle spinning machine. The electromagnetic shielding test was performed according to IEEE-299 specification at 2000MHz. The range was selected to reflect mobile phones, wireless fidelity, Bluetooth and GPS transmission range frequencies. Four samples of conductive fabrics were used in the work, as 0°/0°, 90°/90°, 0°/90° and 90°/0, respectively. The fabric sample with 0°/90° alignment was found to give the best electromagnetic shielding at -65.79dBM. The initial results also show that the hybrid conductive fabrics have large potential to be utilized for shielding electromagnetic radiation (EMR).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.