Electromagnetic Radiation Shielding Research Articles

Application of Innovative Electromagnetic Screens for Reconstruction and Restoration of Buildings

Protective properties of composite electromagnetic screens on the base of conventional commercial paints were studied. The shielding fillers included metal-containing products from industrial wastewater treatment. Such compositions with a thickness of 100 to 150μm, were found to allow reaching high-frequency electromagnetic radiation shielding coefficients up to 3.0-3.5. Reflection coefficients of electromagnetic waves reach up to 0.3, which meets contemporary technical requirements.

Frequency and bandwidth modulation of a wide band-stop metamaterial for EMI shielding applications

In this paper, a µ-near-zero wide band-stop metamaterial (MM) shield is conducted for electromagnetic interference (EMI) shielding purposes in the C- and X-band. The proposed design intends to employ a shared MM structure to serve two distinct microwave bands with extended shielding bandwidth. The proposed structure consists of metal strip coupled four identical quartiles based unique mirror symmetric resonator and designed on a low-loss Rogers 5880 substrate within a compact physical dimension of 7.5 mm × 7.5 mm × 1.575 mm. The speciality of the proposed MM is its wide band-stop functionality with maximum shielding bandwidth and effectiveness of 4.33 GHz and 66.6 dB, respectively. Moreover, four shorting metal strips among adjacent quartiles can control the shielding spectrum from C-band to X-band with an outstanding band-stop enhancement capability of 170.63 %, which significantly outperforms the existing MMs. Therefore, the proposed MM structure can be utilized for two distinct wide frequency spectrums shielding by introducing simple shorting metallic strips. The electromagnetic radiation shielding phenomena are also explained using surface current and electric and magnetic field distribution. The proposed MM prototypes are fabricated and experimentally verified with numerical results. The promising shielding performance of the developed MM demonstrates the potentiality for shielding undesired electromagnetic radiation.

Synthesis and characterization of Ag-doped cerium oxide nanoparticles for electromagnetic radiation shielding.

In the current study, CeO2: Ag (0 and 11 mol) nanoparticles (NPs) were synthesized by solution combustion method using Aloevera extract as reducing agent. As-obtained NPs were characterized by standard techniques. Bragg's reflections confirm the formation of a single-phase cubic structure of CeO2:Ag NPs. Crystalline size is calculated using both the W-H plot and Scherrer's equation. Crystallite size found to decrease with increase in the dopant concentration. EDAX pattern confirmed the presence of Ce, O and Ag. Direct energy band calculated using Wood and Tauc's was found to be in the range of 2.9-2.2 eV for 0 and 11 mol, respectively. Fourier transformation infrared spectroscopy (FTIR) analysis confirmed the presence of the functional groups. Total shielding efficiency (SET) will give the best representation of EMI shielding properties. SET values calculated for a wide range of wavelengths are found to be as follows: near infrared (1.65 × 102 dB), mid infrared (9.78 × 101 dB) and far infrared (6.32 × 101 dB), followed by microwave region (MW) (6.46 × 101 dB), ultra-high frequency (UHF) (7.31 × 101 dB), very high frequency (VHF) (8.27 × 101 dB), high frequency (HF) (9.26 × 101 dB), medium frequency (MF) (1.02 × 102 dB), low frequency (LW) (1.12 × 102 dB), very low frequency (VLF) (1.22 × 102 dB), ultra-low frequency (ULF) (1.42 × 102 dB) and extremely low frequency (ELF) (1.52 × 102 dB). SET values of CeO2:Ag NPs are compared with other traditional materials and nanocomposites and found to be potential use in EMI shielding applications.

Hybrid knitted fabric for electromagnetic radiation shielding: thermo-physical properties

Textile materials for protection against electromagnetic radiation are used now not only for special purposes but in everyday clothing too. In this regard, the thermo-physical properties of such materials are very important. In this study, the hybrid knitted fabrics with electromagnetic shielding properties manufactured on 8E flat-bed machine from 0.12 mm stainless steel wire and 30 × 2 tex cotton yarn have been tested. Fabric samples differ by variant of stainless steel wire incorporation (separately or along with cotton yarn) and their positioning in the structures (loop and/or tuck). Hybrid fabric formed by the alternation of two courses of rib 1 × 1 from cotton yarn and two courses from steel wire has higher porosity and therefore higher relative water vapor permeability and lower thermal conductivity compared with fabric formed from cotton yarn and a steel wire simultaneously. The research results showed that the introduction of stainless steel wire along with cotton yarn into the knitted structure leads to changes in stitch density and therefore in the area of porosity compared with cotton fabric. The thermal conductivity coefficient and evaporative resistance of these fabrics are similar to cotton 1 + 1 rib fabric. Thus, the studied hybrid knitted fabrics with shielding properties against electromagnetic radiation can be recommended for clothing manufacturing. The half-Milano rib fabric knitted from cotton yarn and a steel wire with the greatest electromagnetic interference shielding effectiveness has a good level of comfort similar to cotton fabric.

Synthesis and characterization of calcium-iron-chromium nanocomposites for electromagnetic radiation shielding application.

Over a century, shielding harmful electromagnetic radiations (EMR) and finding a suitable material, which can replace lead has become the major interest of researchers in this field. Herein, calcium-iron-chromium oxide nanocomposites with the different atomic ratios are synthesized using the solution combustion method. The as-obtained nanoparticles (NPs) are subjected to several structural and surface characteristics such as powder X-ray diffraction, scanning electron microscopy, elemental diffraction X-ray analysis, Fourier Transform Infrared Spectroscopy and UV-visible spectroscopy analysis were performed to confirm the successful synthesis. Furthermore, the EMR shielding of as-procured NPs is investigated and observed that the obtained NPs show good shielding properties.

Synthesis and characterisation of Zn-doped cerium oxide nanoparticles for electromagnetic radiation shielding.

CeO2-NPs (nanoparticles) exhibit a variety of properties, which have prompted researchers to explore various applications, such as gas sensing, biomedical, Electromagnetic Interference (EMI) shielding, etc. Zn-doped CeO2-NPs with concentrations ranging from 7 to 11mol were synthesised using Aloe vera extract as a reducing agent by the solution combustion method. As obtained, NPs were characterised by standard techniques. Braggs reflections confirm the formation of a single-phase cubic structure of CeO2Zn NPs. Crystalline size is calculated using both the W-H plot and the Scherrer equation, which were found to be 12 and 9nm, respectively. The Energy-dispersive X-ray analysis (EDAX) pattern confirmed the presence of Ce, O and Zn. The direct energy band values are found to be decreasing from 3 to 2.87eV with an increase in the doping concentration of Zn from 7 to 11mol. Total shielding efficiency (SET) will give the best representation of shielding properties. The SEt values of CeO2Zn NPs are compared to those of other conventional materials and NP materials, finding significant applications in EMI shielding.

Advances in magnetic nano-wave absorbing materials

Magnetic materials are materials with specific magnetic properties, produced mainly by chemical methods such as co-saturation and high temperature pyrolysis, and with controllable product morphology and size. Magnetic particles have a high surface activity and a tendency to agglomerate, which can not only improve their dispersion and biocompatibility, but also achieve specific functions through surface modification in the actual research process. The research and application of wave-absorbing materials will have a major impact on the development of civilian electromagnetic radiation shields. Absorbents with good wave-absorbing properties are at the core of wave absorbing materials, and to meet the requirements of their thin, light, wide and strong properties, absorber research has also advanced towards high efficiency, composites, compatibility and intelligence. By summarising and analysing existing research, this paper provides a comprehensive overview of the research achievements and applications of magnetic wave absorbing materials in the medical and military fields to further explore the application potential, current challenges and future developments of such materials in various fields.

High-Performance Transparent Ultrabroadband Electromagnetic Radiation Shielding from Microwave toward Terahertz.

In the era of fifth-generation networks and Internet-of-Things, the use of multiband electromagnetic radiation shielding is highly desirable for next-generation electronic devices. Herein, we report a systematic exploration of optoelectronic behaviors of ultrathin-silver-based shielding prototype (USP) film structures at the nanometer scale, unlocking the transparent ultrabroadband electromagnetic interference (EMI) shielding from microwave to terahertz frequencies. A theoretical model is proposed to optimize USP structures to achieve increased transparency, whereby optical antireflection resonances are introduced in dielectrics in conjunction with remarkable EMI shielding capability. USP can realize a state-of-the-art effective electromagnetic radiation shielding bandwidth with measured frequencies from 8 GHz up to 2 THz. Experimental results show that a basic USP (dAg = 10 nm) offers an average shielding efficiency of ∼27.5 dB from the X- to Ka-bands (8-40 GHz) and maintains a stable shielding performance of ∼22.6 dB across a broad range of 0.5-2 THz, with a measured optical transmittance of ∼95.2%. This extraordinary performance of ultrathin-silver-based film structures provides a new ultrabroadband EMI shielding paradigm for potential applications in next-generation electronics.

Graphene Nanocomposites for Electromagnetic Interference Shielding—Trends and Advancements

Electromagnetic interference is considered a serious threat to electrical devices, the environment, and human beings. In this regard, various shielding materials have been developed and investigated. Graphene is a two-dimensional, one-atom-thick nanocarbon nanomaterial. It possesses several remarkable structural and physical features, including transparency, electron conductivity, heat stability, mechanical properties, etc. Consequently, it has been used as an effective reinforcement to enhance electrical conductivity, dielectric properties, permittivity, and electromagnetic interference shielding characteristics. This is an overview of the utilization and efficacy of state-of-the-art graphene-derived nanocomposites for radiation shielding. The polymeric matrices discussed here include conducting polymers, thermoplastic polymers, as well as thermosets, for which the physical and electromagnetic interference shielding characteristics depend upon polymer/graphene interactions and interface formation. Improved graphene dispersion has been observed due to electrostatic, van der Waals, π-π stacking, or covalent interactions in the matrix nanofiller. Accordingly, low percolation thresholds and excellent electrical conductivity have been achieved with nanocomposites, offering enhanced shielding performance. Graphene has been filled in matrices like polyaniline, polythiophene, poly(methyl methacrylate), polyethylene, epoxy, and other polymers for the formation of radiation shielding nanocomposites. This process has been shown to improve the electromagnetic radiation shielding effectiveness. The future of graphene-based nanocomposites in this field relies on the design and facile processing of novel nanocomposites, as well as overcoming the remaining challenges in this field.

Analysis of Vibration, Deflection Angle and Surface Roughness in Water-Jet Cutting of AZ91D Magnesium Alloy and Simulation of Selected Surface Roughness Parameters Using ANN.

The use of magnesium alloys in various industries and commerce is increasing due to their properties such as high strength and casting properties, high vibration damping capability, good shielding of electromagnetic radiation and high machinability. Conventional machining methods can, however, pose a risk of ignition. AWJM is a safe alternative to conventional machining, but the deflection and vibration of the water jet can affect surface quality. Therefore, the aim of this study was to investigate the effects of selected AWJM parameters on the surface quality and vibration of machined magnesium alloys. Jet deflection angle, surface roughness parameters and vibration during AWJM were investigated. The findings showed that higher skewness occurred at a lower abrasive flow rate, while higher average values of the Sku roughness parameter were obtained at ma = 8 g/s in the range of 60-140 mm/min. It was also observed that higher vibration values occurred at ma = 8 g/s. The input parameters for creating an artificial neural network (ANN) model used in this study were the cutting speed vf and the mass flow rate ma. The results of this study provided valuable insights into ways of ensuring a safe and efficient machining environment for magnesium alloys. The use of ANN modeling for predicting the vibration and surface roughness of AZ91D magnesium alloy after water-jet cutting could be an effective tool for optimizing AWJM parameters.

Effect of SiC particle size on the strength and stiffness of porous Si3N4–SiC composites fabricated via a low-temperature sintering process

Porous Si3N4–SiC composites are potentially very attractive in various applications such as chemical-gas industries, nuclear power plants, automobile industries, and as heat-absorbing materials for solar thermal power plants and electromagnetic radiation shielding materials for commercial and military applications. The fabrication of these advanced composites generally requires expensive raw materials and very high temperatures necessitating advanced sintering techniques, thereby making these materials very expensive. Within the scope of this work, a novel technique for fabricating these porous composites at a low temperature of 1200 °C using phosphoric acid both as a binder and pore former has been proposed. Two different Si3N4–SiC composites with different SiC particle sizes and varying SiC content, with overall porosities in the range of 33–43 vol%, have been fabricated. A detailed study of the influence of the composites’ composition on their microstructure and mechanical properties has been carried out. The results show that both the SiC particle size and its content strongly influence the strength, stiffness, and elastic anisotropy of the fabricated composites. The most optimum composition resulting in the best combination of stiffness and strength in the porous composites has been identified. This yields a longitudinal elastic constant of 50 GPa, a flexural strength of ∼80 MPa, and compressive strength of ∼200 MPa. These values fare well in comparison to porous Si3N4–SiC composites reported in the literature, albeit fabricated at much higher temperatures in comparison to this work. The strength and stiffness of the porous composite with composition Si3N4-20 vol% fine SiC are considerably higher than monolithic porous Si3N4.

Electromagnetic Radiation Knowledge, Risk Awareness, and Shielding Practices of South Korean Occupational Therapists During Videofluoroscopic Swallowing Study: A Survey study

The videofluoroscopic swallowing study (VFSS) based on electromagnetic radiation is an instrumental test for diagnosing and rehabilitating dysphagia that is performed by many occupational therapists (OTs) in South Korea. This study aimed to investigate current electromagnetic radiation knowledge, risk awareness, and shielding practices of OTs performing VFSS and to identify educational experience on radiation protection. An online survey was conducted from April 2019 to June 2022, and a total of 69 responses were used for analysis. The mean correct score of ‘Radiation Knowledge’ was 3.24 ± 1.98 (out of 10). Mean scores of ‘Risk Awareness’ and ‘Shielding Practice’ were 2.18 ± 0.53 and 3.02 ± 0.74 (out of 5), respectively. Multiple regression analyses revealed that radiation knowledge (β = 0.292, p = 0.012) and risk awareness (β = 0.495, p 0.001) were significant factors associated with shielding practices. Ninety-five percent of respondents had no radiation-related educational experience, and 83% reported that the reason for not participating was due to a lack of educational opportunities.

Disposal of used nanosorbents obtained during wastewater purification from Ni2+ ions in powder paint materials

The prospects of increasing the level of environmental safety of industrial enterprises as a result of the implementation of the latest sorption technologies for wastewater treatment are considered. An analysis of the effectiveness of the existing methods of sorption water purification, which contain compounds of heavy metals, was carried out. Highly effective magnetic sorbents were obtained by electroerosion dispersion, which contains polyvalent iron oxides.
 The effect of the method of introducing the sorbent into wastewater on the degree of its purification was investigated. The most effective results in water purification were achieved with the use of freshly obtained powder of electroerosion dispersion of iron in water in the form of a suspension, which allows to achieve a high degree of water purification from zinc ions - more than 99%. Such water meets the standards for washing parts in galvanic production with regard to the content of nickel ions. The expediency of recycling spent nano-sorbents in the composition of powder paint and varnish materials is shown. When a coating chemically stable in water treatment waste, which has ferromagnetic properties, is included in the composition, in quantity15% by weight high corrosion resistance of the coating is ensured and shielding of electromagnetic radiation increases approximately 3 times compared to the standard sample. The use of research results at enterprises will prevent environmental pollution with toxic substances, change outdated production technologies, ensure efficient and rational use of water, raw materials and energy in the industrial production system.

Emergence of MXene and MXene-Polymer Hybrid Membranes as Future- Environmental Remediation Strategies.

The continuous deterioration of the environment due to extensive industrialization and urbanization has raised the requirement to devise high-performance environmental remediation technologies. Membrane technologies, primarily based on conventional polymers, are the most commercialized air, water, solid, and radiation-based environmental remediation strategies. Low stability at high temperatures, swelling in organic contaminants, and poor selectivity are the fundamental issues associated with polymeric membranes restricting their scalable viability. Polymer-metal-carbides and nitrides (MXenes) hybrid membranes possess remarkable physicochemical attributes, including strong mechanical endurance, high mechanical flexibility, superior adsorptive behavior, and selective permeability, due to multi-interactions between polymers and MXene's surface functionalities. This review articulates the state-of-the-art MXene-polymer hybrid membranes, emphasizing its fabrication routes, enhanced physicochemical properties, and improved adsorptive behavior. It comprehensively summarizes the utilization of MXene-polymer hybrid membranes for environmental remediation applications, including water purification, desalination, ion-separation, gas separation and detection, containment adsorption, and electromagnetic and nuclear radiation shielding. Furthermore, the review highlights the associated bottlenecks of MXene-Polymer hybrid-membranes and its possible alternate solutions to meet industrial requirements. Discussed are opportunities and prospects related to MXene-polymer membrane to devise intelligent and next-generation environmental remediation strategies with the integration of modern age technologies of internet-of-things, artificial intelligence, machine-learning, 5G-communication and cloud-computing are elucidated.

Wide-Band Electromagnetic Radiation Shielding Construction Based on Pseudooval Scattering Elements for Information Protection Against Leakage Via Electromagnetic Channel

The paper considers the results of a study of the influence of the relative position of moisture-containing pseudooval scattering elements with linear dimensions of 10…20, 2…4, 1…4 and 1…2 mm on the electromagnetic radiation reflection coefficients values of the electromagnetic radiation shielding structures, including these elements, and the effective scattering surface of the ground objects, on the surface of which the indicated structures are fixed or applied. Placement of three- or two-layer structures formed on the basis of pseudooval elements with linear dimensions of 2...4, 1...4, 1...2 mm, between two monolayers made on the basis of elements with dimensions of 10...20 mm, leads to the decrease up to –17,6 dB of the electromagnetic radiation reflection coefficients values in the frequency range of 2–12 GHz of the electromagnetic radiation shielding structures, including these elements. The values of the effective scattering surface of ground objects, on the surface of which the indicated electromagnetic radiation shielding structures are located, vary within 0,08...11,80 m 2 , which is the reason of a significant difficulty in intercepting information about the location and characteristics of ground objects by means of technical intelligence in the frequency range of their operation.

Production of barite-doped yarns and testing their usability for ionizing and electromagnetic radiation shielding

Barite-doped and polypropylene-based masterbatches were produced at different ratios, and 1 × 1 Rib type weaving process was carried out by obtaining filament yarns. While the morphological and structural properties of the obtained textile products were investigated with XRD, FTIR and SEM, thermal stabilities were investigated with TGA. Then, the shielding abilities of the products against ionizing and electromagnetic radiation were analyzed. The shielding properties against ionizing radiation were studied with mass attenuation coefficient, half value layer, effective atomic number and radiation protection efficiency parameters at nine different energies in the energy range of 17.75 to 81.0 keV. The shielding properties against electromagnetic radiation were studied in the range of 15 to 40 GHz. To test the usability of the products, antibacterial activity tests, breaking strength and elongation tests and surface resistivity tests were carried out. It has been observed that all products are suitable in terms of usability and also, ionizing and electromagnetic radiation shielding properties increase with increasing barite content, and the product containing 10% barite is a good shielding material for radiation compared to others. The data of the present survey can be quite helpful for possible applications such as aerospace, medicine, science, nuclear industry.

Shielding of Electromagnetic Radiation by an Artificial Magnetic Conductor Based on an Isotropic Composite Material Consisting of Capacitive Gratings

Shielding of Electromagnetic Radiation by an Artificial Magnetic Conductor Based on an Isotropic Composite Material Consisting of Capacitive Gratings

An Innovative Approach to Electromagnetic Radiation Shielding by Graphene: An Experimental Study

The need to use electromagnetic radiation in clinical practices indicates the defense from the electromagnetic radiation itself which have a destructive impact on the human tissue and brain. Therefore, the wearable aprons as electromagnetic shields are the protective gears required to enhance their blend and structure to attain effective shielding. The aprons that are made of textile materials are widely considering protecting from electromagnetic radiation. In this context, conventional textile-materials are not appropriate, but their adaptations, which are in the form of composites, are utilized. The contemporary literature contributed by the recent past research works has several methods of making textile electromagnetic radiation shield. Recent innovations of conductive polymer application in electromagnetic radiation shielding were considered. The treating of textile materials by conductive polymer displayed higher electrical property in the form of electromagnetic radiation shield. Protective mechanisms such as aprons of electromagnetic radiation shielding are essential for enhancing their blend and structure to attain effective radiation shielding. The carbon nanotube is deliberated as a productive polymer result for the electromagnetic radiation shielding. The review experiment aimed to discuss the possibility of using a graphene coat on the polymer composite of carbon nanotube and to improve the practical solution for shielding the protective aprons. The confines of a polymer composite of carbon nanotube attenuation stages are deliberated in this article. Keywords: Carbon Nanotube, Electromagnetic Radiation, Graphene.

Polypyrrole-Coated Melamine Sponge as a Precursor for Conducting Macroporous Nitrogen-Containing Carbons

Macroporous open-cell melamine sponges were coated with a conducting polymer, polypyrrole, during in-situ oxidative polymerization of pyrrole. Two samples, differing in polypyrrole content, 8.2 and 27.4 wt%, were prepared. They were exposed to various temperatures up to 700 °C in an inert atmosphere. The macroporous structure and mechanical integrity were preserved after this process. This converted both the polypyrrole coating and the melamine sponge to macroporous nitrogen-containing carbons. The changes in molecular structure in the course of carbonization were followed by elemental analysis and FTIR and Raman spectra. The specific surface area of polypyrrole-coated sponge increased from ca. 90 to ca. 300 m2 g−1 along with accompanying increase in the porosity. The conductivity of the sponges was recorded as a function of compression in a newly developed apparatus. The sponge containing 27.4 wt% pyrrole had conductivity of the order of 10−2 S·cm−1 at 0.1 MPa pressure, which was reduced by four orders of magnitude when exposed to 400–500 °C and nearly recovered after the temperature reached 700 °C. The sponges were tested in electromagnetic radiation shielding and displayed both radiation absorption and, to a lower extent, radiation reflection proportional mainly to the samples’ conductivity.

EVALUATION OF ELECTROMAGNETIC RADIATION SHIELDING CHARACTERISTICS OF FACING BUILDING VATERIALS

The article presents the results of theoretical studies of the protective properties of composite facing materials based on a dielectric matrix with an electrically conductive non-magnetic filler in a wide frequency range of incident electromagnetic radiation. Expressions are got for the values of the transmission, reflection and absorption, and the electromagnetic radiation shielding efficiency calculated on their basis. The dependences of the permittivity and electrical conductivity of the composite on the volume fraction of the electrically conductive additive required for calculations were got based on the hypothesis of similarity, considering the nonzero conductivity of the dielectric matrix. Satisfactory agreement between the calculation results and the measured shielding characteristics of specimens of metal silicate materials based on calcium hydro silicates and copper powder was established. The results presented show the adequacy of the proposed calculation method and indicate that it can be used for preliminary estimates of the shielding characteristics when designing electromagnetic radiation shields based on composite facing materials.