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Other Leak Detection Technologies
Published in Justin Starr, Water and Wastewater Pipeline Assessment Technologies, 2021
Radar reflections or backscatters are often impacted significantly by the dielectric constant of the material encountered. Dielectric constants are a measurement of how a material responds to an electric field. This property, which is also known as permittivity, describes the degree of polarization a material undergoes when it is exposed to electromagnetic waves. Materials with high permittivities or large dielectric constants are polarized much more than materials with lower dielectric constants. This principle is used regularly by electrical and electronics engineers, as selecting materials with high dielectric constants in electronic component design can be a key method of increasing capacitance.
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Published in Heinz P. Bloch, Kenneth E. Bannister, Practical Lubrication for Industrial Facilities, 2020
Heinz P. Bloch, Kenneth E. Bannister
A dielectric is an electric insulating material, one that opposes a flow of current through it. There are two properties that contribute to this characteristic. One is resistivity, the specific resistance that a dielectric offers under moderate conditions of voltage. The other is dielectric strength, the ability to prevent arcing between two electrodes at high electric potentials. Though the two properties are not directly related, it so happens that commercial insulating materials of high dielectric strength also possess adequate resistivity. In the insulation of high-voltage electrical conductors, therefore, it is ordinarily dielectric strength that is of the greater concern.
Electrical Field in Materials
Published in Ahmad Shahid Khan, Saurabh Kumar Mukerji, Electromagnetic Fields, 2020
Ahmad Shahid Khan, Saurabh Kumar Mukerji
Dielectrics can be solids, liquids, or gases. Solid dielectrics are the most commonly used and many solids are very good insulators as well. Solid dielectrics include porcelain, glass, and most of the plastics. The air, nitrogen, and sulfur hexafluoride are the most commonly used gaseous dielectrics. A high vacuum with unity relative dielectric constant is a nearly lossless dielectric.
Ground penetrating radar (GPR) applications in concrete pavements
Published in International Journal of Pavement Engineering, 2022
Alireza Joshaghani, Mehran Shokrabadi
From an electrical viewpoint, materials can be classified as either conductor or dielectric. Conductor materials such as copper or aluminum transmit electric current. However, most pavements are composed of dielectric materials that do not conduct electric current but can sustain an electric field. It is extremely desirable to establish conclusions about the conditions of pavements in an analytical manner. The theory of radar wave propagation in solid objects can be simplified for practical structural testing purposes. Comprehensive attention has been given to the understanding of dielectric properties of concrete pavements to develop interpretation features. The electrical properties that govern the propagation of electromagnetic waves in materials are electrical conductivity and dielectric values. Solid information about the dielectric properties of concrete over a wideband of frequencies is required. Dielectric materials refer to non-conducting or semiconducting materials that can store potential energy. Pavement materials are often considered as dielectric materials. Signal velocity is taken to be inversely proportional to the square root of the relative permittivity (ϵr), which ranges from 1.0 (air) to 81 (water). A dielectric constant value shows both electric and magnetic properties, which describe the permittivity and the permeability of materials, respectively (Avelar Lezama 2007). Since the magnetic permeability of materials is not substantial, the magnetic property is not that important.
Natural fibre filament for Fused Deposition Modelling (FDM): a review
Published in International Journal of Sustainable Engineering, 2021
H. J. Aida, R. Nadlene, M.T. Mastura, L. Yusriah, D. Sivakumar, R. A. Ilyas
Produce composites by combining polymer and natural fibre as filler, can produce the insulator materials, such as wire and cable wrapper. In Narayan Nayak (Narayan Nayak, Dr. Reddappa H. N, Ganesh R Kalagi, & Vijendra Bhat, 2017) paper has extract about electrical properties of natural fibre reinforced polymer. Dielectric strength is one of the important parameter in electrical which measure the withstand of voltage without breakdown. Along with the mechanical, physical and thermal properties, electrical properties also play an important role in producing composites. Mechanical is about the durability in term of tensile, bending, fatigue, and impact. Physical are about the durability of composites in moisture, flow, and density, while thermal properties are about how high the composite can withstand in certain temperature without degrade. In this paper also stated that 1.8–2.6 is the constant for dielectric constant that non-polar polymer lies and might be greater than that one for another polymer. Lesser the value of dielectric constant, the more efficient it might be (Narayan Nayak et al. 2017). But due to some of disadvantages of natural fibre especially the hydrophilic properties, it might increase the value of dielectric and lower the efficiency itself. In way to prevent this issue, the chemical treatment is done towards the natural fibre as to decrease the moisture absorption. By doing the alkaline treatment, not just can increase the efficiency in electrical insulator properties, but also in term of mechanical and physical properties (Narayan Nayak et al. 2017).
Determination of ionic strength due to magnesium sulfate heptahydrate in water by means of its permittivity in the microwave range
Published in Journal of Microwave Power and Electromagnetic Energy, 2020
Edel Serafín Hernández Gómez, José-Luis Olvera-Cervantes, Benito Corona Vásquez, Alonso Corona Chávez, Laura Sol Perez Flores, Tejinder Kaur Kataria
The dielectric constant is defined as the measure of the ability of a material to store electromagnetic energy. The dielectric loss factor is characterized by the amount of electromagnetic energy converted into heat in a material (Coronel et al. 2008). The loss factor due to dipolar rotation () and the loss factor due to ionic conduction () are the two mechanisms that contribute to the dielectric permittivity in the microwave frequencies (Pradhan et al. 2008). The loss factor and are related as follows: where