scholarly journals Absorption of Electromagnetic Waves by Fe\(_3\)O\(_4\)/Paraffin Composite Materials

2019 ◽  
Vol 29 (1) ◽  
pp. 63
Author(s):  
Hong Thi Minh Nguyen ◽  
Duy Van Nguyen ◽  
Co Dang Nguyen ◽  
Tu Dinh Bui ◽  
Thang Duc Pham
Keyword(s):  
Composite Materials ◽  
Electromagnetic Waves ◽  
Weight Ratio ◽  
Absorption Capacity ◽  
Sample Thickness ◽  
Simulation Calculation ◽  
Absorbing Materials ◽  
Large Dielectric Loss ◽  
Electromagnetic Pollution ◽  
Harmful Effects

Electromagnetic pollution in general and the harmful effects of microwave radiation in particular on environment is currently in the urgent stage. To eliminate the effect of electromagnetic energy the most common methods relies on the use of absorbing materials with large absorption capacities in wide frequency band. In this paper, we investigate the capability of absorption of electromagnetic waves of Fe3O4 nanoparticles in paraffin basis. The Fe3O4/paraffin composite materials were prepared with a weight ratio of 35%/65%. The dielectric constant (εr) and the magnetic permeability (μr) in the frequency (f) range from 8 to 18 GHz were measured for various sample thicknesses. The results indicated a large dielectric loss and strong thickness dependence of absorption capacity. The maximum absorption coefficient (RL) is of order -13.6 dB, corresponding to the achieved absorbance of 96,9% for the 2.6 mm of sample thickness. The experimental results are consisted with our simulation calculation.

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.

scholarly journals Microwave-Boosted One-Step Synthesis of Nanocrystal N-Doped 2D Carbon/Ni Composite with High Electromagnetic Absorption Performance

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1718
Author(s):  
Pan Luo ◽  
Song Lyu ◽  
Bowen Zhang ◽  
Hui Wang ◽  
Yanping Zhou ◽  
...  
Keyword(s):  
Absorption Capacity ◽  
Sample Thickness ◽  
Relaxation Processes ◽  
Mixed Solution ◽  
Absorption Bandwidth ◽  
Electromagnetic Absorption ◽  
One Step ◽  
Absorption Performance ◽  
Electromagnetic Pollution ◽  
High Absorption

As the problems of electromagnetic pollution and interference are becoming increasingly serious, the development of electromagnetic absorption materials with a high absorption capacity and broad absorption bandwidth are stringently needed. In this work, an N-doped 2D carbon/Ni complex is synthesized through direct microwave irradiation on a mixed solution of nickel nitrate, urea, and agarose under N2. The electromagnetic absorption performance can be tuned by controlling the Ni content. Specifically, minimum reflection loss values (RLmin) of −65.5 dB at 15.8 GHz with an effective absorption bandwidth (EAB) of 4.2 GHz at a sample thickness of 1.47 mm, and −55.4 dB at 11.8 GHz with an EAB of 3 GHz at a sample thickness of 1.92 mm can be obtained. The outstanding performance of electromagnetic absorption is attributed to the multiple polarization relaxation processes and the synergistic effect between 2D carbon sheets and Ni particles.

Composite Materials Based on Silicone Rubber Used to Mitigation Electromagnetic Pollution

2015 ◽  
Vol 1114 ◽  
pp. 76-80
Author(s):  
Elena Valentina Stoian ◽  
Vasile Bratu ◽  
Florina Violeta Anghelina ◽  
Ileana Nicoleta Popescu
Keyword(s):  
Composite Materials ◽  
Silicone Rubber ◽  
Electromagnetic Waves ◽  
Polymer Matrix Composites ◽  
Raw Materials ◽  
Digital Processing ◽  
Thin Layers ◽  
Matrix Composites ◽  
High Attenuation ◽  
Electromagnetic Pollution

Rapid developments in telecommunications and digital processing of information are facing the problem of electromagnetic wave pollution and interference. The aim of this article is the characterization at microwave frequencies of composite materials based on silicone rubber. These materials contain 80% siloxane rubber and only 20% powdery feeling like nanocarbon and pyrite cinder. To achieve these objectives were reviewed and selected raw materials and characteristics were determined in a structural material, the electromagnetic attenuation as well as electrically, by making measurements of electrical conductivity of thin layers of polymer matrix composites produced by the doctor blade technique. Starting from sample siloxane rubber, i.e. without additives or filler reinforcement in compression analysis we find that reinforcing agents leads to increased values of the modulus of elasticity in especially for pyrite ashes. For materials analyzed in this paper, measurements were made in the frequency range between (1-18) GHz and have found high attenuation over 45 dB in the case of composite materials with pyrite ash filler. So we can say that this materials can used for shielding against electromagnetic waves in order to protect the human factor. The novelty of the paper consists in the compositions of the specimens and their mechanical and electromagnetic characteristics.

scholarly journals Superparamagnetic ZnFe2O4 Nanoparticles-Reduced Graphene Oxide-Polyurethane Resin Based Nanocomposites for Electromagnetic Interference Shielding Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1112
Author(s):  
Raghvendra Singh Yadav ◽  
Anju ◽  
Thaiskang Jamatia ◽  
Ivo Kuřitka ◽  
Jarmila Vilčáková ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Electromagnetic Waves ◽  
Spinel Ferrite ◽  
Ferrite Nanoparticles ◽  
Resin Matrix ◽  
Polyurethane Resin ◽  
Reduced Graphene ◽  
Znfe2o4 Nanoparticles ◽  
Electromagnetic Pollution

Superparamagnetic ZnFe2O4 spinel ferrite nanoparticles were prepared by the sonochemical synthesis method at different ultra-sonication times of 25 min (ZS25), 50 min (ZS50), and 100 min (ZS100). The structural properties of ZnFe2O4 spinel ferrite nanoparticles were controlled via sonochemical synthesis time. The average crystallite size increases from 3.0 nm to 4.0 nm with a rise of sonication time from 25 min to 100 min. The change of physical properties of ZnFe2O4 nanoparticles with the increase of sonication time was observed. The prepared ZnFe2O4 nanoparticles show superparamagnetic behavior. The prepared ZnFe2O4 nanoparticles (ZS25, ZS50, and ZS100) and reduced graphene oxide (RGO) were embedded in a polyurethane resin (PUR) matrix as a shield against electromagnetic pollution. The ultra-sonication method has been used for the preparation of nanocomposites. The total shielding effectiveness (SET) value for the prepared nanocomposites was studied at a thickness of 1 mm in the range of 8.2–12.4 GHz. The high attenuation constant (α) value of the prepared ZS100-RGO-PUR nanocomposite as compared with other samples recommended high absorption of electromagnetic waves. The existence of electric-magnetic nanofillers in the resin matrix delivered the inclusive acts of magnetic loss, dielectric loss, appropriate attenuation constant, and effective impedance matching. The synergistic effect of ZnFe2O4 and RGO in the PUR matrix led to high interfacial polarization and, consequently, significant absorption of the electromagnetic waves. The outcomes and methods also assure an inventive and competent approach to develop lightweight and flexible polyurethane resin matrix-based nanocomposites, consisting of superparamagnetic zinc ferrite nanoparticles and reduced graphene oxide as a shield against electromagnetic pollution.

The Elastic Characterization of Composite Based on Ultrasonic Waves

2021 ◽  
Author(s):  
Y. H. Park ◽  
J. Dana
Keyword(s):  
Composite Materials ◽  
Fatigue Failure ◽  
Elastic Constants ◽  
Material Properties ◽  
Weight Ratio ◽  
Transversely Isotropic ◽  
Ultrasonic Waves ◽  
Material Strength ◽  
Isotropic Composite

Abstract Anisotropic composite materials have been extensively utilized in mechanical, automotive, aerospace and other engineering areas due to high strength-to-weight ratio, superb corrosion resistance, and exceptional thermal performance. As the use of composite materials increases, determination of material properties, mechanical analysis and failure of the structure become important for the design of composite structure. In particular, the fatigue failure is important to ensure that structures can survive in harsh environmental conditions. Despite technical advances, fatigue failure and the monitoring and prediction of component life remain major problems. In general, cyclic loadings cause the accumulation of micro-damage in the structure and material properties degrade as the number of loading cycles increases. Repeated subfailure loading cycles cause eventual fatigue failure as the material strength and stiffness fall below the applied stress level. Hence, the stiffness degradation measurement can be a good indication for damage evaluation. The elastic characterization of composite material using mechanical testing, however, is complex, destructive, and not all the elastic constants can be determined. In this work, an in-situ method to non-destructively determine the elastic constants will be studied based on the time of flight measurement of ultrasonic waves. This method will be validated on an isotropic metal sheet and a transversely isotropic composite plate.

scholarly journals A study into the scale effect on the strength properties of polymer composite materials

2019 ◽  
Vol 5 (2) ◽  
pp. 103-108
Author(s):  
Valentina V. Kiryushina ◽  
Yuliya Yu. Kovaleva ◽  
Petr A. Stepanov ◽  
Pavel V. Kovalenko
Keyword(s):  
Composite Materials ◽  
Polymer Composite ◽  
Scale Effect ◽  
Mechanical Characteristics ◽  
Full Scale ◽  
Sample Thickness ◽  
Polymer Composite Materials ◽  
Test Machine ◽  
Test Results ◽  
Laboratory Sample

Polymer composite materials (PCM) are used extensively and are viewed as candidates for application in various industries, including nuclear power. Despite a variety of methods and procedures employed to investigate the mechanical characteristics of PCMs, the use of the laboratory sample mechanical test results to design and model large-sized structures is not always fully correct and reasonable. In particular, one of the problems is concerned with taking into account the scale parameter effects on the PCM strength and elastic characteristics immediately in the product. The purpose of the study is to investigate the scale effects on the mechanical characteristics of glass reinforced plastics using phenolformaldehyde and silicon-organic binders and a fabric quartz filler. Samples of four different standard sizes under GOST 25604-82 and GOST 4648-2014 were tested for three-point bending using an LFM-100 test machine to estimate the scale effect. The thicknesses of the model samples were chosen with regard for the wall thicknesses of full-scale products under development or manufactured commercially and the test machine features, and varied in the limits of 1.6 to 7.5 mm. The tests showed that strength decreased as the sample thickness was increased to 3 mm and more both at room and elevated (200 to 500 °C) temperatures, which can be described by an exponential function based on the Weibull statistical model. The values of the Weibull modulus that characterizes the extent of the scale effect on the strength of the tested materials were 4.6 to 6.7. The average bend strength in the sample thickness range of 3 mm and less does not vary notably or tends to increase slightly as the thickness is increased. This fact makes it possible to conclude that estimation of allowable stresses in a thin-wall product requires the use of test results for samples with a thickness that is equal to the product wall thickness since standard samples may yield overestimated allowable stress values and lead, accordingly, to incorrect calculations of the strength factor. The results obtained shall be taken into account when defining the allowable levels of operation for full-scale products and structures of polymer composites based on the laboratory sample strength data as well as when estimating their robustness as a characteristic of the product’s fail-safe operation.

Investigation of Mechanical Properties of Silk and Epoxy Composite Materials

2021 ◽  
Vol 889 ◽  
pp. 27-31
Author(s):  
Norie A. Akeel ◽  
Vinod Kumar ◽  
Omar S. Zaroog
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Composite Materials ◽  
Epoxy Composite ◽  
Mechanical Test ◽  
Weight Ratio ◽  
Industrial Applications ◽  
Sem Analysis ◽  
Equivalent Strength ◽  
Test Impact

This research Investigates the new composite materials are fabricated of two or more materials raised. The fibers material from the sources of natural recycled materials provides certain benefits above synthetic strengthening material given that very less cost, equivalent strength, less density, and the slightest discarded difficulties. In the current experiments, silk and fiber-reinforced epoxy composite material is fabricated and the mechanical properties for the composite materials are assessed. New composite materials samples with the dissimilar fiber weight ratio were made utilizing the compression Molding processes with the pressure of 150 pa at a temperature of 80 °C. All samples were exposed to the mechanical test like a tensile test, impact loading, flexural hardness, and microscopy. The performing results are the maximum stress is 33.4MPa, elastic modulus for the new composite material is 1380 MPa, and hardness value is 20.64 Hv for the material resistance to scratch, SEM analysis of the microstructure of new composite materials with different angles of layers that are more strength use in industrial applications.

Investigation of the Mechanical Behavior of Natural Vegetable Fibers Used in Composite Materials for Structural Strengthening

2021 ◽  
Vol 888 ◽  
pp. 15-21
Author(s):  
Ivelina Ivanova ◽  
Jules Assih ◽  
Dimitar Dontchev
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Fiber Composite ◽  
Low Cost ◽  
Weight Ratio ◽  
Synthetic Fiber ◽  
Engineering Structures ◽  
Hemp Fiber ◽  
Plant Fibers ◽  
Hemp Fibers

This research aims at studying the mechanical properties of industrial hemp fibers and promoting their use as a reinforcing composite material for strengthening of civil engineering structures. Natural hemp fibers are of great interest due to the following advantages they have: low cost, high strength-to-weight ratio, low density and non-corrosive properties. The use of plant fiber composite materials has increased significantly in recent years because of the negative reduction impact on the environment. For example, the tendency to use renewable resources and their possibility for recycling. They cause fewer health and environmental problems than synthetic fibers. Natural fibers, in addition to environmental aspects, have advantages such as low densities, i.e. have low weight, interesting mechanical properties comparable to those of synthetic fiber materials, and last but not least, low cost. Composites based on natural plant fibers can be used to reinforce or repair reinforced concrete structures, as shown by research on flax fiber composites. These concretes specimens strengthened with biocomposite materials have very good resistance to bending and significantly increase the rigidity of the structure. The results show that the hemp fiber reinforcement has significant effects on the strengthening and increase in flexural strength from 8% to 35 %.

Tribological behaviour of fibre-reinforced thermoset polymer composites: A review

2020 ◽  
Vol 234 (11) ◽  
pp. 1439-1449
Author(s):  
Santosh Kumar ◽  
KK Singh
Keyword(s):  
Composite Materials ◽  
Polymer Composites ◽  
Matrix Material ◽  
Research Work ◽  
Weight Ratio ◽  
Tribological Behaviour ◽  
Glass Fibres ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Thermoset Polymer

Application of fibre-reinforced polymer composites has increased over the last two decades as compared to conventional materials. This improvement in the application of fibre-reinforced polymer composites is attributed to their unique material properties, such as high strength and stiffness-to-weight ratio, specific modulus and internal vibration damping. However, in most of the industrial applications, composite materials encounter tribological complications. Economic indicators and market dynamics suggested that the market for composite materials is booming and the dominant materials are carbon fibres, glass fibres and thermoset polymer (polyester resin) in resin segments. That is why tribological characteristics are crucial in designing carbon and glass-based fibre-reinforced polymer components. Owing to this importance, the study of tribological behaviour of fibre-reinforced polymer composite materials has expanded significantly. The present study has made an attempt to review the fundamental tribological applications and critical aspects of fibre-reinforced polymers, based on research work, which has been carried out over the past couple of decades. This work has primarily focused on the fibre-reinforced polymer composites, based on carbon and glass fibres with thermosets as the matrix material for probing into tribological behaviours. In the process, the focus has largely been on the most commonly occurring erosive and abrasive mode of wear process.

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