Measurement of Stratified Distributions of Dielectric Properties and Dependent Physical Parameters

1997 ◽  
Vol 500 ◽  
Author(s):  
A. V. Mamishev ◽  
Y. Du ◽  
B. C. Lesieutre ◽  
M. Zahn
Keyword(s):  
Dielectric Properties ◽  
Electric Potential ◽  
Dielectric Materials ◽  
Transformer Oil ◽  
Physical Parameters ◽  
Moisture Concentration ◽  
Multi Wavelength ◽  
Spatially Periodic ◽  
Calibration Techniques ◽  
And Diffusion

ABSTRACTRecent advances in ω-k (frequency-wavenumber) interdigital dielectrometry are described. Using this technology, information about the microstructure of dielectric materials is obtained by applying to the sensor-dielectric interface a spatially periodic electric potential swept in frequency from 0.005 Hz to 10,000 Hz. The penetration depth of the electric field is proportional to the spatial wavelength of the electric potential. Application of multi-wavelength electrode arrangements allows measurement of stratified distributions of complex dielectric permittivity. Calibration techniques serve to relate the distributed dielectric properties of materials to other physical variables, such as density, porosity, cracking, lamination, and diffusion of contaminants into the material. The specific problem treated in this paper is in the measurement of moisture concentration distribution in transformer pressboard during the diffusion of water molecules from ambient transformer oil. The output of interdigital sensors is strongly influenced by the microgranularity of the material's surface. Although this dependence complicates interpretation of the measurements in some applications, the variation of the output may also be used to characterize the shape of the surface on the microscale.

scholarly journals Finite Element Analysis of the Microwave Ablation Method for Enhanced Lung Cancer Treatment

Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3500
Author(s):  
Marija Radmilović-Radjenović ◽  
Martin Sabo ◽  
Marta Prnova ◽  
Lukaš Šoltes ◽  
Branislav Radjenović
Keyword(s):  
Dielectric Properties ◽  
Cancer Cells ◽  
Microwave Ablation ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Surrounding Tissue ◽  
Physical Parameters ◽  
Medical Procedure ◽  
Ablation Zone ◽  
Specific Absorption

Knowledge of the frequency dependence of the dielectric properties of the lung tissues and temperature profiles are essential characteristics associated with the effective performance of microwave ablation. In microwave ablation, the electromagnetic wave propagates into the biological tissue, resulting in energy absorption and providing the destruction of cancer cells without damaging the healthy tissue. As a consequence of the respiratory movement of the lungs, however, the accurate prediction of the microwave ablation zone has become an exceptionally demanding task. For that purpose, numerical modeling remains a primordial tool for carrying out a parametric study, evaluating the importance of the inherent phenomena, and leading to better optimization of the medical procedure. This paper reports on simulation studies on the effect of the breathing process on power dissipation, temperature distribution, the fraction of damage, and the specific absorption rate during microwave ablation. The simulation results obtained from the relative permittivity and conductivity for inflated and deflated lungs are compared with those obtained regardless of respiration. It is shown that differences in the dielectric properties of inflated and deflated lungs significantly affect the time evolution of the temperature and its maximum value, the time, the fraction of damage, and the specific absorption rate. The fraction of damage determined from the degree of tissue injury reveals that the microwave ablation zone is significantly larger under dynamic physical parameters. At the end of expiration, the ablation lesion area is more concentrated around the tip and slot of the antenna, and the backward heating effect is smaller. The diffuse increase in temperature should reach a certain level to destroy cancer cells without damaging the surrounding tissue. The obtained results can be used as a guideline for determining the optimal conditions to improve the overall success of microwave ablation.

Dielectric properties of Shell oil transformer oil with impurities of carbon nanotubes and fullerene C60

2021 ◽  
Vol 24 (04) ◽  
pp. 413-418
Author(s):  
O.V. Kovalchuk ◽  
◽  
I.P. Studenyak ◽  
T.M. Kovalchuk ◽  
E.A. Ayryan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Dielectric Properties ◽  
Fullerene C60 ◽  
Transformer Oil ◽  
C60 Fullerene ◽  
Cooling Efficiency ◽  
Fullerene Concentration ◽  
Multiwall Nanotubes

At the temperature 293 K, the influence of two types of nanoimpurities (carbon multiwall nanotubes and C60 fullerene) both separately and together on the dielectric properties of Shell oil transformer oil has been studied. It has been shown that these impurities do not significantly effect on the value of the dielectric permittivity of Shell oil, but more significantly increase its conductivity. It has been found that in the presence of nanotubes inside Shell oil, the dependence of its electrical conductivity on the fullerene concentration is nonmonotonic. The samples with the fullerene concentration 100 ppm have the highest conductivity. At the fullerene concentration 300 ppm, the conductivity of Shell oil with the impurities of carbon nanotube and C60 fullerene becomes almost equal to the electrical conductivity of Shell oil only with the impurities of carbon nanotubes. It has been suggested that C60 fullerene can be used to reduce the electrical conductivity of Shell oil with magnetic nanoparticles required to increase the cooling efficiency of transformers under the action of their own magnetic field.

scholarly journals Double-layer core/shell-structured nanoparticles in polyarylene ether nitrile-based nanocomposites as flexible dielectric materials

RSC Advances ◽  
2017 ◽  
Vol 7 (47) ◽  
pp. 29306-29311 ◽  
Author(s):  
Yong You ◽  
Weihua Han ◽  
Ling Tu ◽  
Yajie Wang ◽  
Renbo Wei ◽  
...  
Keyword(s):  
Energy Storage ◽  
Dielectric Properties ◽  
Double Layer ◽  
Dielectric Materials ◽  
Core Shell ◽  
Energy Storage Density ◽  
Storage Density ◽  
Polyarylene Ether Nitrile

The surface of BaTiO3 was modified with CPEN and NH2-CuPc, and the obtained CPEN-f-BT@CuPc reinforced the performance of PEN. The fabricated PEN-based nanocomposite shows stable dielectric properties and energy storage density from RT to 160 °C.

Laser-induced deposition of copper from deep eutectic solvents: optimization of chemical and physical parameters

2021 ◽  
Author(s):  
Andrey Shishov ◽  
Dmitry Gordeychuk ◽  
Lev Logunov ◽  
Elena Danilova ◽  
Aleksandra Levshakova ◽  
...  
Keyword(s):  
Deep Eutectic Solvents ◽  
Dielectric Materials ◽  
Physical Parameters ◽  
Physical Methods

Fabrication of the conductive copper structures on the surface of various dielectric materials is quite important for many fields of science. There are a lot of chemical and physical methods...

scholarly journals Utilization of Second Order Slip, Activation Energy and Viscous Dissipation Consequences in Thermally Developed Flow of Third Grade Nanofluid with Gyrotactic Microorganisms

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 309 ◽  
Author(s):  
Zahra Abdelmalek ◽  
Sami Ullah Khan ◽  
Hassan Waqas ◽  
Hossam A. Nabwey ◽  
Iskander Tlili
Keyword(s):  
Activation Energy ◽  
Viscous Dissipation ◽  
Microbial Fuel Cells ◽  
Liquid Metals ◽  
Second Order ◽  
Transformer Oil ◽  
Third Grade ◽  
Physical Parameters ◽  
Gyrotactic Microorganisms ◽  
Motion Features

In recent decades, an interest has been developed towards the thermal consequences of nanofluid because of utilization of nano-materials to improve the thermal conductivity of traditional liquid and subsequently enhance the heat transportation phenomenon. Following this primarily concept, this current work investigates the thermal developed flow of third-grade nanofluid configured by a stretched surface with additional features of activation energy, viscous dissipation and second-order slip. Buongiorno’s nanofluid model is used to explore the thermophoresis and Brownian motion features based on symmetry fundamentals. It is further assumed that the nanoparticles contain gyrotactic microorganisms, which are associated with the most fascination bioconvection phenomenon. The flow problem owing to the partial differential equations is renovated into dimensional form, which is numerically simulated with the help of bvp4c, by using MATLAB software. The aspects of various physical parameters associated to the current analysis are graphically examined against nanoparticles’ velocity, temperature, concentration and gyrotactic microorganisms’ density distributions. Further, the objective of local Nusselt number, local Sherwood number and motile density number are achieved numerically with variation of various parameters. The results presented here may find valuable engineering applications, like cooling liquid metals, solar systems, power production, solar energy, thermal extrusion systems cooling of machine equipment, transformer oil and microelectronics. Further, flow of nanoparticles containing gyrotactic microorganisms has interesting applications in microbial fuel cells, microfluidic devices, bio-technology and enzyme biosensors.

Millimeter-wave dielectric properties of single-crystal ferroelectric and dielectric materials

2011 ◽  
Vol 58 (1) ◽  
pp. 18-29 ◽  
Author(s):  
John S Mccloy ◽  
Konstantin A Korolev ◽  
Zijing Li ◽  
Mohammed N Afsar ◽  
Shanmugavelayutham K Sundaram
Keyword(s):  
Dielectric Properties ◽  
Single Crystal ◽  
Millimeter Wave ◽  
Dielectric Materials

B-O Bond Character and Microwave Dielectric Properties of (1-x)CaTiO3-xCa(Zn1/3Nb2/3)O3 Perovskite Ceramics

2009 ◽  
Vol 421-422 ◽  
pp. 69-72
Author(s):  
Jie Shen ◽  
Wen Chen ◽  
Jing Zhou ◽  
Jie Zhu ◽  
Qiong Lei
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Dielectric Materials ◽  
Solid State Reaction Method ◽  
Dielectric Constants ◽  
Identical Result ◽  
Microwave Dielectric ◽  
Calculation Results ◽  
The Relationship

The relationship between the character of the B-site cation–oxygen bond and the microwave dielectric properties in perovskites dielectric materials was studied in this paper. The atomic net charge of CaTiO3 (CT) and Ca(Zn1/3Nb2/3)O3 (CZN) was calculated respectively. The calculating result implies that the covalency of B-O bonds in CZN is stronger than that in CT. This predicted that the dielectric constant and loss of the ceramics will decrease after CZN incorporated in CT. To confirme the prediction, (1-x)CT-xCZN microwave dielectric ceramics were prepared by solid state reaction method with ZnNb2O6 as precursor. The structure analysis in terms of tolerance factor gives an identical result as calculation. The microwave dielectric properties, such as dielectric constants, Q×f values and τf were studied as a function of composition. With x increasing from 0.2 to 0.8, the dielectric constant linearly decreases from 109 to 49.37, the Q×f value increases from 8,340 to 13,200 GHz, and τf decreases from 321 to -18 ppm/°C. The properties trends are consistent with the previous calculation results, and confirm the relationship between the character of B-O bond and dielectric properties.

The role of interfacial zone in dielectric properties of transformer oil-based nanofluids

2016 ◽  
Vol 23 (6) ◽  
pp. 3364-3372 ◽  
Author(s):  
Diaa-Eldin A. Mansour ◽  
Ahmed M. Elsaeed ◽  
Mohamed A. Izzularab
Keyword(s):  
Dielectric Properties ◽  
Transformer Oil ◽  
Interfacial Zone
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