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Radiation-cured epoxy and acrylate-based materials are used in a number of applications where curing under ionizing radiations is preferred to the classical thermal curing process. Because mechanical properties are often the key features in these applications much less attention has been paid to their electrical properties. We report on the dielectric properties of two classes of radiation-cured materials...
In this paper, a new theory allowed calculating the pyroelectric coefficient “p” using the diffusion of a thermal wave within materials having a pyroelectric effect. The demonstration is performed on materials composed by various percentages of a cycloaliphatic epoxy (CE) resin and of a flexibilizing comonomer (1,6-hexanediol diglycidyl ether — HDGE). By using an electric field measurement technique...
The increase of current transformer (CT) failure rate in PLN P3B Jawa and Bali within the last five years has put CT as a critical asset. In order to prevent existing CTs from the similar failure, the assessment method needs to be evaluated. For this purpose, further investigation was conducted on three sister units of two failed CTs by performing measurements and tear down. The investigations reveal...
The emergence of UHV AC/DC transmission systems and the installation of UHV equipment in heavily-polluted and high-altitude environments places challenges on the improvement of insulation systems. Part of the challenge can be met by the introduction of new dielectrics that offer superior properties. In particular the development of polymer-based systems that incorporate nano-sized fillers may allow...
Since insulation plays a significant role in ensuring the reliability of an polymeric underground cable, many researchers across the globe are very much interested to investigate the mechanisms responsible for insulation degradation when it is subjected to high electrical stresses. One of the ways to monitor the processes leading to breakdown is by observing a phenomenon known as electroluminescence...
A new strategy for preparation of nano-sized barium titanate (BaTiO3) particles was applied by using: layered (tetramethyl)ammonium titanate, barium acetate and tetramethylammonium hydroxide. An addition of barium salt to aqueous layered titanate colloids leads to a precipitation phenomenon by which barium titanate precursor was obtained. The mechanism of this reaction is based on ions exchange which...
The geometry optimization, elastic constant, electronic band structure, density of state (DOS) and optical properties of perovskite SnZrO3 (SZ) are investigated from first principles calculation using the Density Functional Theory (DFT) within Local Density Approximation (LDA). All the calculations are performed using the Cambridge Serial Total Energy Package (CASTEP) computer code. The independent...
The space-domain volume integral equation (VIE) method is presented for the analysis of three-dimension (3-D) scattering from dielectric frequency selective structures (DFSS). The method solves directly for the electric field in order to easily enable periodic boundary conditions in the spatial domain. The computation of the spatial domain periodic Green's function (PGF) is accelerated by the modified...
Radiation in the material medium from the transverse slot cut in the screen of the coaxial line has been studied by the magnetomotive forces method theoretically. Internal and external conductivities of the arc and circumferential slots, radiating into the space filled by an imperfect dielectric with tg δ ≤ 1, have been investigated. The radiation and reflection coefficients of the transverse slot...
This study focuses on the seals of validation, sealing written documents, used in the Western Middle Ages, especially wax seals. We use THz spectroscopy and imaging for non-destructive evaluation of natural materials within those seals. Using a time domain THz spectroscopy and imaging system, THz transmission images are generated in the 0.1–3 THz range and demonstrate that the spectral properties...
It was investigated the influence of local heterogeneities in the dielectric sample in the form of cylindrical holes of different depths on the parameters of the response signal using a multisensor control system based on the phenomenon mechanoelectrical transformations. The high efficiency of multisensor system to reliably register the local volume defects of small size was shown.
The effect of gamma-ray irradiation on relative permittivity, ac conductivity and dielectric loss tangent of epoxy resin and polyethylene has been investigated. Laminated samples were irradiated by 60Co gamma source at room temperature in air with a dose rate of 10 kGy/h and the total dose were 100 kGy and 1000 kGy. The dielectric properties were measured by using a Precision LCR Meter (Agilent E4980A)...
The radiation of a radially oriented dipole in the presence of a semi-infinite isorefractive cone of circular cross-section is calculated analytically via the two-interval Sturm-Liouville formulation, which was previously used by the authors to treat the electrostatic problem of the dielectric cone. This method presents an alternative to the Kontorovich-Lebedev transform method, which was used by...
An H-shaped cross slotted aperture-coupled microstrip patch antenna with double-sided notches is presented. By proper choice of the notch dimensions, aperture size and foam material height, a wide band and high gain operation could be realized. The impedance bandwidth (based on a −10 dB return loss) of the designed antenna reaches about 12.5%. The maximum gain of the antenna is 9.35dBi, and the whole...
This paper focused on epoxy-based nanodielectric composites with 5, 10, 15 and 20 wt.% of silica constituents prepared using simple mechanical mixing technique along with required curing cycles. The experimentally clarified dielectric constant (ϕ′) and dissipation factor (tanδ) are influenced by addition of nanosilica is discussed on the basis of the three core interface model proposed for interaction...
Nowadays electric utilities are facing major problems due to the ageing and deterioration of high voltage (HV) power equipments in their operating service period. There are several solid materials are used in high voltage power system equipments for insulation purpose. The insulators used in HV power equipment always have a small amount of impurity inside it. The impurity is mainly in the form of...
Propagation of surface plasmons at metal surfaces is receiving much interest nowadays because of its broad range of potential applications, like subwavelength photonics or biosensing. Although plasmonic devices achieve unique properties, surface plasmons suffer from high attenuation because of the absorption losses in the metal. This limitation can be overcome by providing the material adjacent to...
Thin layers of material are commonly occurring structures in many modern integrated photonics devices. As the overall geometric complexity of these integrated structures increases, it is convenient to employ flexible full-wave numerical electromagnetic simulators for their design. In this paper we discuss and present a technique for embedding thin layer material responses into one such numerical technique,...
Two different types of instrumentation have been utilized to characterize thin film samples. New techniques have been developed so that the dielectric permittivity values can be determined accurately at microwave as well as at millimeter wave and terahertz frequencies. A specially designed slotted cavity for X-band microwave measurement has been employed with a vector network analyzer to overcome...
Optimizing the performance of optical fibres or photonic devices often boils down to the identification of a proper dielectric material, or to a systematic modification of an existing basic material. With modern ab initio simulation methods based on density functional theory, it is possible to model dielectric properties from the bottom-up. Starting with the atomic and electronic structure of the...
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