The Formation of New Critical System by Electric Breakdown in Percolation System

1990 ◽  
Vol 195 ◽  
Author(s):  
V.A. Garanov ◽  
A.A. Kalachev ◽  
A.M. Karimov ◽  
A.N. Lagar´kov ◽  
S.M. Matitsin ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Dielectric Constant ◽  
Composite Materials ◽  
Dielectric Properties ◽  
Density Current ◽  
Critical Percolation ◽  
Frequency Range ◽  
Critical System ◽  
Current Action ◽  
Binary Composite

ABSTRACTA new way of obtaining binary composite materials having some properties of the critical percolation system is presented..These materials can be obtained by high-density current action on an initially well conducting mixture.This action destroys part of contacts between adjacent conducting granules bringing the system to the quasi-critical state.It is shown that quasi-critical s stems may have high values of dielectric constant ε′ ∼ 102-106 101 in the frequency range 0<f<1010Hz.Formation and dielectric properties of the systems are studied both by computer simulation and experi mentally.

Dielectric Studies of Admicelled Natural Rubber with Poly(3-Trimethoxysilylpropyl Methacrylate)

2013 ◽  
Vol 844 ◽  
pp. 373-376
Author(s):  
Suparat Nooma ◽  
Rathanawan Magaraphan
Keyword(s):  
Dielectric Constant ◽  
Composite Materials ◽  
Dielectric Properties ◽  
Chemical Modification ◽  
Natural Rubber ◽  
Microwave Frequency ◽  
Dielectric Studies ◽  
Frequency Range ◽  
Admicellar Polymerization ◽  
Methoxy Groups

In this work, 3-trimethoxysilylpropyl methacrylate (MPS) was used as a substrate for coating on natural rubber (NR) particles by admicellar polymerization. The incorporation of MPS monomer, consisting of silicon element and 3 reactive methoxy groups (R-Si(OCH3)), is expected to increase dielectric properties of NR. Under the admicellar polymerization, the R-Si(OCH3) groups can be hydrolyzed and condensed into polysiloxane existed on NR particles. This method aims to prepare composite materials from NR and MPS with various amounts of MPS. The effects of microwave frequency and chemical modification by admicellar polymerization were studied. The dielectric properties of admicelled natural rubber (adNR) with PMPS were investigated at 20 °C in a frequency range extended from MHz to GHz. The results showed that the dielectric constant of adNR increased with PMPS contents. To study the effect of crosslinking on the dielectric properties of adNR, the dielectric spectroscopy measurements were performed on prevulcanized and non-prevulcanized adNR. The investigation showed that the dielectric constant of non-prevulcanized adNR was less than prevulcanized adNR.

Effect of moisture content on dielectric properties of banana leaves and peels in frequency range of 1–20 GHz

Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Soumya Sundar Pattanayak ◽  
Soumen Biswas
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Measurement Data ◽  
Banana Peel ◽  
Frequency Range ◽  
Proposed Model ◽  
Banana Leaves ◽  
Banana Leaf

Abstract The quality of agricultural products can be remotely sensed and enhanced by determining the dielectric properties. This paper studies the dielectric properties of banana leaf and banana peel over the frequency range 1–20 GHz using the open-ended coaxial probe (OCP) method. A new curve fitting model is proposed to characterize the dielectric properties of banana leaf and banana peel. The different moisture content (MC) levels are considered for both banana leaf and banana peel samples and, their dielectric properties are characterized. Further, the banana leaf and banana peel’s measurement data are compared with the data obtained using the proposed model. In addition, Root Mean Square Error (RMSE) and R-squared (R 2) are calculated to validate the performance of the proposed model. In case of banana leaf at 68.26% MC, the dielectric constant achieves the value of R 2 and RMSE of 0.98 and 0.0648, respectively. Similarly, dielectric loss achieves the value of R 2 and RMSE of 0.88 and 0.0795, respectively. Further, for banana peel at 80.89% MC, the dielectric constant achieves the value of R 2 and RMSE of 0.99 and 0.2989, respectively. Similarly, dielectric loss achieves the value of R 2 and RMSE of 0.96 and 0.6132, respectively.

Effect of Sintering Temperature on Dielectric Properties of CaCu3Ti4O12 Ceramics Prepared by Mechanochemical Process

2014 ◽  
Vol 974 ◽  
pp. 157-161
Author(s):  
Masturah Mohamed ◽  
Mahesh Talari ◽  
Mohd Salleh Mohd Deni ◽  
Azlan Zakaria
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Sintering Temperature ◽  
Processing Conditions ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
Grain Sizes ◽  
Barrier Capacitance ◽  
Different Temperatures ◽  
Increasing Temperature

CaCu3Ti4O12(CCTO) is well known to have colossal dielectric constant in the range of 105.It is widely accepted that this phenomenon may be attributed to internal layer barrier capacitance (IBLC) model. The dielectric properties of CCTO were reported to be strongly dependent on the processing conditions and grain size. In this work, CCTO samples with different grain sizes were produced by varying sintering temperature in order to investigate IBLC effect on dielectric properties of CCTO. The samples were sintered at four different temperatures, (T=1100°C, 1050°C, 1000°C and 950°C). Dielectric measurements were carried out for the samples in the frequency range of 102– 106Hz using impedance spectrometer. Electron micrographs showed that increasing temperature promoted the grain growth of CCTO while sintering. The internal crystalline defects are seen to play major role by increasing the grain conductivity in dipole formation and increased the dielectric constant of the samples.

Effect of Fungicide Treatment on Dielectric Properties of a Vegetable Seed

2015 ◽  
Vol 5 (2) ◽  
Author(s):  
Vishal Singh Chandel ◽  
Atiq UR Rahmanm ◽  
J. P. Shukla ◽  
Rajiv Manohar ◽  
Mohd. Shafi Khan
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Considerable Change ◽  
Frequency Range ◽  
Dielectric Parameters ◽  
Hewlett Packard ◽  
Fungicide Treatment ◽  
Vegetable Seed

Effect of fungicides' (thiram, captan, carbendazim, bagalol) treatment on dielectric constant and dielectric loss of a vegetable seed, namely the brinjal at given moisture content and bulk density was examined using Hewlett-Packard (HP-4194A) impedance/gain phase analyzer over the frequency range of 0.01 to 10 MHz and temperature range of 30-450C. Julabo (temperature controller, F-25, Germany) was used for keeping the temperature of seeds constant. Study showed that fungicide treatment cast considerable change in dielectric parameters namely the dielectric constant and dielectric loss.

Dielectric Properties of MgAl2O4 Transparent Nano-Ceramic

2008 ◽  
Vol 368-372 ◽  
pp. 412-413 ◽  
Author(s):  
Jie Zhang ◽  
Deng Xue Wu ◽  
Xiang Hui Chang ◽  
Tie Cheng Lu ◽  
Yi Hang Jiang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Low Dielectric Constant ◽  
Frequency Range ◽  
Low Dielectric

Dielectric constant and dielectric dissipation of MgAl2O4 transparent nano-ceramics were measured at different frequencies. The results indicated that the transparent nano-ceramic has a very low dielectric constant and low dielectric dissipation in frequency range of 1K~9MHz, but the dissipation of is independent of frequency. The dielectric constant of the transparent nano-ceramic does not vary signifycantly with temperature.

scholarly journals Study of Dielectric Properties of Fenugreek Seeds (Trigonella Foenum Graecum)

2014 ◽  
Vol 66 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Mohd. Shafi Khan ◽  
Vishal Singh Chandel ◽  
Rajiv Manohar ◽  
Jagdeesh Prasad Shukla
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Ac Conductivity ◽  
Frequency Range ◽  
Fenugreek Seeds ◽  
Temperature Controller ◽  
Trigonella Foenum Graecum ◽  
Fenugreek Seed

Abstract The present paper studied the dielectric constant, dielectric loss, and ac conductivity of fenugreek seed, a medicinal seed (Trigonella foenum graecum), within the frequency range of 10 kHz and 10 MHz and the temperature range of 30°C and 50°C. Impedance gain/phase analyser (HP 4194 A) was used to measure the dielectric constant and the dielectric loss and Julabo (temperature controller, F-25, Germany) was used for keeping the temperature of fenugreek seeds constant. It was found that the dielectric constant and the dielectric loss decrease with the increase in the frequency while the same increase with the increase in temperature and moisture content. The ac conductivity increased with the increase in frequency, moisture and temperature.

scholarly journals Dielectric and Conductivity Properties of Some Wood Composites

2016 ◽  
Vol 8 ◽  
pp. 51-60
Author(s):  
K.Ch. Varada Rajulu ◽  
B.N. Mohanty
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Low Temperature ◽  
Temperature Region ◽  
Loss Factor ◽  
Wood Composites ◽  
Frequency Range ◽  
Increasing Temperature ◽  
Coaxial Probe

This study presents the dielectric and conductivity properties as function of temperature and frequency of wood based composites. These properties were measured by an open-ended coaxial probe at frequency range between 100 kHz to 100MHz, temperature from 30OC to 200OC which is fully computer interfaced. It has been observed that dielectric constant (ε') and dielectric loss factor (ε") increase with increasing temperature and decrease with increasing frequency. At low temperature region, the conductivity depends significantly on the frequency. However, with the increase in temperature dielectric relaxation takes place and the dependency of the conductivity on frequency get reduced. The patterns of variation were established for the studied specimens and discrepancies were discussed. The study of dielectric properties will help in improving the drying, heating and gluing processes of wood and wood based products.

Simulation and experimentation of wide frequency electromagnetic shielding coating used for carbon fiber composite materials of track vehicles

2019 ◽  
Vol 33 (01n03) ◽  
pp. 1940020 ◽  
Author(s):  
Ming Gong ◽  
Shou-Guang Sun ◽  
Lin Sun ◽  
Ai-Qin Tian ◽  
Qiang Li
Keyword(s):  
Computer Simulation ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Fiber Composite ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Frequency Range ◽  
Simulation Technology ◽  
Carbon Fiber Composite ◽  
Fiber Composite Materials

Computer Simulation Technology EM and Computer Simulation Technology Microwave Studio electromagnetic simulation software were used to simulate the carbon fiber composite materials with a new type of wide frequency electromagnetic shielding coating. DC magnetic field, low-frequency electromagnetic fields, and mid-high frequency electromagnetic shielding effectiveness analysis model were established in order to study the influence of permeability, conductivity, coating thickness and other parameters in the typical frequency range research on the shielding effectiveness. The results show that the composite coating material with reasonable design can effectively enhance the electromagnetic shielding performance of carbon fiber composite materials in the DC [Formula: see text]18 GHz frequency range.

Bulk and In-Circuit Dielectric Characterization of LTCC Tape Systems Through Millimeter Wave Frequency Range

2011 ◽  
Vol 2011 (1) ◽  
pp. 000740-000746 ◽  
Author(s):  
Bradley Thrasher ◽  
Deepukumar Nair ◽  
James Parisi ◽  
Glenn Oliver ◽  
Michael A. Smith
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Millimeter Wave ◽  
Design Stage ◽  
Frequency Range ◽  
Dielectric Thickness ◽  
Dielectric Characterization ◽  
Wide Range ◽  
Comprehensive Characterization

Low Temperature Co-fired Ceramic (LTCC) material systems offer a highly versatile microwave and millimeter wave packaging platform. Extremely low microwave loss, excellent control of dielectric constant, uniform dielectric thickness, non-existent water absorption leading to very high hermeticity, ability to support multilayer structure leading to 3-dimensional packaging, ability to embed passive functions within the tape layers, availability of a wide range of metallizations, etc. are some of the key advantages of LTCC for microwave packaging. One of the important parameters which needs to be determined at the very early stages of circuit designs are the dielectric properties - dielectric constant and loss tangent, both of which are functions of frequency. These properties need to be known accurately over the entire frequency range of operation for the circuit. For LTCC based designs, the use of dielectric constant of bulk material can lead to deviations between the performance expected at the design stage and for the fabricated circuit. Such deviations are a significant concern for broadband circuits as well as for circuits with sharp resonant behavior such as filters. One of the significant sources of deviation between bulk LTCC and “in-circuit” dielectric constant is the nature of the thick film metallizations used in LTCC technology. Work described here is a comprehensive characterization of three DuPont™ GreenTape™ LTCC systems 951, 943, and 9K7 - in the frequency range 10 to 70 GHz. Both bulk and “in-circuit” dielectric properties with silver and gold metallizations are studied to quantify the deviations in dielectric properties. A Fabry-Perot open resonator technique is used for the bulk characterization while printed ring resonators are used for the in-circuit characterization. This comprehensive characterization will provide key design data for LTCC designers in the 10 – 70 GHz frequency range.

scholarly journals Study of structural and dielectric properties of Nickel-doped BaTiO3 material

2019 ◽  
Vol 8 (3) ◽  
pp. 228-233
Author(s):  
Hafes Ed-Dnoub ◽  
Ouafae El Ghadraoui ◽  
Mohammed Zouhairi ◽  
Ahmed Harrach ◽  
Tajeddine Lamcharfi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Electron Microscope ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Scanning Electron Microscope ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray ◽  
Perovskite Type ◽  
Scanning Electron

In this work, the effect of nickel (Ni) insertion on the structural and dielectric properties of BaTiO3 material was investigated. A series of powders of composition Ba1-xNixTiO3 (x = 0, 0.05, 0.1, 0.15 and 0.20) were synthesized by solid method. The analysis by X-Ray Diffraction (XRD) shows that the obtained compounds crystallize in a phase of perovskite type. All the peaks are indexed in a phase of quadratic symmetry. Characterization by the Scanning Electron Microscope (SEM) indicates a heterogeneous microstructure of the grains. The study by spectroscopy of impedance in the frequency range [500Hz-1MHz] highlighted the effect of the nickel insertion on the transition temperature and the dielectric constant value.

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