Study on Relationship between Carbon Black and Dielectric Properties of Tire Rubber in UHF Band

2014 ◽  
Vol 536-537 ◽  
pp. 1456-1459 ◽  
Author(s):  
Ting Qiang Song ◽  
Yan Zhou ◽  
Lian Xiang Ma

In UHF band, the effects of carbon black component on the dielectric properties of rubber composites are studied through experiments. The results show that the content of the carbon black have great effects on the dielectric properties of the composite rubber. The higher content of the carbon black in the rubber composite, the larger the permittivity and dielectric loss tangent. At the same time, the operating frequencies also have great influence on the dielectric properties of the rubber composite. In the UHF band, the permittivity and the dielectric loss tangent of the rubber composites decrease with frequency increasing.

2012 ◽  
Vol 02 (03) ◽  
pp. 1230010 ◽  
Author(s):  
L. B. KONG ◽  
L. LIU ◽  
J. W. ZHAI ◽  
Z. W. LI ◽  
Z. H. YANG

Dielectric properties of ferrite ceramics have been less reported than their magnetic properties. Our recent study indicated that ferrite ceramics with very low dielectric loss tangent can be developed by using appropriate sintering aids, together with the optimization of other sintering parameters such as sintering temperature and time duration. Among various candidates of sintering aids, Bi 2 O 3 is the most promising one. It is important to find that the optimized concentration of sintering aid for full densification is not sufficient to achieve lowest dielectric loss tangent. This short review was aimed to summarize the understanding in microstructural evolution, grain growth, densification and dielectric properties of ferrite ceramics as a function of sintering aid concentration and sintering parameters, which could be used as a guidance to develop ferrite ceramics with low dielectric loss tangents for various applications.


1958 ◽  
Vol 36 (12) ◽  
pp. 1672-1677
Author(s):  
A. G. Mungall

Measurement at millimeter wavelengths of the dielectric properties of low loss materials by a free space technique is described. The dielectric constant is determined from the Brewster angle, and the dielectric loss tangent from the attenuation coefficient measured at the Brewster angle of incidence. Results are given for bakelite at wavelengths between 5 and 10 mm. Details of the instrument, which was specifically designed for these measurements, are also given.


2019 ◽  
Vol 60 (12) ◽  
pp. 87-90
Author(s):  
Ignat S. Dolgin ◽  
◽  
Pyotr P. Purygin ◽  
Yury P. Zarubin ◽  
◽  
...  

Three new copolymers based on fluorine-containing derivatives of styrene and α-methylstyrene were obtained. According to the results of the previous stages of the study, copolymers based on styrene derivatives have improved dielectric properties compared to polystyrene and a copolymer of styrene and α-methyl styrene. The dielectric constant ε and dielectric loss tangent tanδ were measured for the initial and synthesized samples of styrene – α-methyl styrene copolymer at Samara Electromechanical Plant OJ-SC (Samara city, Russia). All measurements of dielectric characteristics were carried out at an alternating current frequency of 10 GHz on a pressed copolymer tablet with a diameter of 10 and a thickness of 3 mm. During the experiment, a measuring stand was used, consisting of a high-frequency signal generator G4-83, an electronically counting frequency meter Ch3-54 with a frequency converter YaZCh-43, a measuring amplifier U2-4; low-frequency signal generator G3-109; measuring unit FKDG 418151.002. The results obtained indicate high values of the dielectric constant. For samples of copolymers of α-methylstyrene – 4-fluoro-α-methylstyrene and styrene – 4-fluoro-α-methylstyrene, values of 4.63 and 4.21, respectively, were obtained. These dielectric permittivity values are superior not only to samples previously obtained during the experiment, but also to some other compounds that are widely used in industry. In particular, the dielectric constant of lavsan, which is used in the manufacture of capacitors, is 3.1-3.3. The improved dielectric constant values are probably related to the high-quality composition of the copolymer. Samples of the copolymer containing 4-fluoro-α-methylstyrene are significantly superior to the copolymer with 2,3,4,5,6-pentafluorostyrene for this characteristic. The values of the dielectric loss tangent are in the range from 8.74∙10−4 to 37.4∙10−4. Given the dielectric characteristics of the synthesized copolymers, we can conclude that there are good prospects for the use of fluorine-containing styrene copolymers. The obtained values of permittivity and dielectric loss tangent indicate a good possible competitiveness of new materials based on new copolymers. In the future, it is planned to study a number of other physicochemical properties of these materials in order to obtain the most complete spectrum of their characteristics.


2018 ◽  
Vol 28 (2) ◽  
pp. 169
Author(s):  
Abbas K. Saadon

The paper presents the production of porcelain for the ceramic by inexpensive natural raw materi-als, the principal raw materials of porcelain composition was selected consisting of 50% kaolin, 25% feldspar, 25% silica, the sample synthesized were characterize by X-ray diffraction (XRD) technique, than study the effect additives at different concentration form titanium oxide (𝑇𝑖𝑂2 )at (2, 5, 10, 15, 20) wt% on some physical and dielectric properties of porcelain. The samples are prepared by the conventional manufacturing method. The physical and dielectric properties of porcelain show that change considerably with the sub-stituent sample. It was found that the increase of the titanium oxide (𝑇𝑖𝑂2 ) additives of all our sample produce increasing in dielectric constant and bulk density, while decreasing with open porosity and dielectric loss tangent.


2020 ◽  
pp. 62-67
Author(s):  
V.M. Generalov ◽  
A.S. Safatov ◽  
M.V. Kruchinina ◽  
A.A. Gromov ◽  
G.A. Buryak ◽  
...  

The dielectric properties of the erythrocyte were studied. Experimental methods and results of measuring the dielectric properties of individual human erythrocyte are presented. The method is theoretically justified. It is established that values of the complex permittivity of the erythrocyte, capacitance, tangent of dielectric losses remains almost constant despite significant changes in conductivity, the content of NaCl of the cell suspension. These values reflect the stability of the studied parameters of erythrocytes under conditions of changes within a wide range of the environment in which the cells are located. Complex cell permittivity and cell dielectric loss tangent are promising parameters for objective diagnostics of human diseases. The introduction of measurements of cell permittivity and cell dielectric loss tangent into medical practice will probably allow us to characterize the process of individual cell self-regulation in more detail.


2011 ◽  
Vol 25 (31) ◽  
pp. 2391-2398 ◽  
Author(s):  
MUANGJAI UNRUAN ◽  
TEERAWAT MONNOR ◽  
RATTIKORN YIMNIRUN ◽  
ORAWAN KHAMMAN ◽  
WANWILAI VITTAYAKORN ◽  
...  

Effects of compressive stress on the dielectric properties of complex perovskite PZBT-PMNT ceramic were investigated. The dielectric properties measured under stress-free condition showed a composite nature with two distinct temperatures of dielectric maximum associated with PZBT and PMNT end members. The dielectric properties under the compressive stress were observed at stress levels up to 230 MPa using a home-built compressometer. The results clearly showed that the compression load significantly reduced both the dielectric constant and the dielectric loss tangent in every measuring frequency. The change of the dielectric constant with stress was attributed to competing influences of the intrinsic contribution of non-polar matrix and the extrinsic contributions of re-polarization and growth of micro-polar regions, while the clamping of the domain walls contributed to the stress-dependent changes of the dielectric loss tangent. Finally, a large drop of the dielectric constant after a stress cycle was likely caused by the stress induced decrease in switchable part of spontaneous polarization.


2008 ◽  
Vol 368-372 ◽  
pp. 940-942
Author(s):  
Hai Yang Zhao ◽  
Wei Min Wang

A series of samples of hexagonal boron nitride-aluminum nitride (10-90, 15-85, 20-80, 25-75, 30-70wt.%) ceramic composites were prepared by spark plasma sintering in a nitrogen atmosphere at 1650 °C-1800 °C for 5min. Different amounts of CaF2 were added as sintering aids. The effects of CaF2 and sintering temperature on densification and dielectric properties were discussed. The addition of CaF2 enhances relative dielectric constant and loss tangent of the samples. The increase in sintering temperature promotes the densification and decreases the dielectric loss tangent. When being sintered at 1700 °C, the relative density, dielectric constant and dielectric loss tangent of the sample with 15wt.%BN are 98.04%, 7.15 and 6.31×10-4 respectively.


2013 ◽  
Vol 753-755 ◽  
pp. 2379-2382
Author(s):  
Shi Meng Xu ◽  
Run Bo Ma ◽  
Jian Hua Du ◽  
Jun Hong Liu ◽  
Qi Jin

Filled the N330 carbon black, silica T80 carbon black and Al powder and Fe2O3 magnetic nanoparticles, the rubber composites on multi-component electromagnetic fillers were prepared according to orthogonal experiment analysis, and the preliminary experiment conclusions of the filler prescription designs were given; Based on the experiment design, the mechanical properties and thermal conductivity of the rubber composite were tested, and the testing results were analyzed by using variance analysis. Thus, the paper shows that the effects of N330 on rubber mechanical properties are significant, and the effects of Al powder on the rubber thermal conductivity are significant. Moreover, it is highly emphasized in this paper that the orthogonal experiment design must be carefully explored before the tests are executed.


2021 ◽  
Vol 14 (2) ◽  
pp. 132-141
Author(s):  
M. N. Lyutikova ◽  
S. M. Korobeynikov ◽  
A. A. Konovalov

Power transformers are key equipment in power generation, transmission, and distribution systems. The reliability of power transformers is based on the performance of the insulation system, which includes solid cellulose insulation and a liquid dielectric. Modern power engineering requires liquid insulation to have excellent insulating properties, high fire resistance, and biodegradability. Mineral oil that has been in use for over 100 years does not meet certain requirements. Therefore, various methods of enhancing the insulating properties of the oil are currently being considered, including mixing it with other liquid dielectrics, which have excellent properties. Synthetic and natural esters are considered as alternative fluids.This article discusses the possibility of enhancing the insulating characteristics of mineral oil with a high content of aromatic hydrocarbons (for example, T-750 oil) by mixing it with synthetic ester Midel 7131. Assessment is given of insulating parameters of the resulting mixtures with an ester fraction in mineral oil from 0% to fifty%. The main characteristics of the mixtures are described, such as density, kinematic viscosity, flash point, dielectric loss tangent, relative dielectric permittivity, breakdown voltage, and moisture content. It is shown that with an increase in the proportion of ester, some parameters of the obtained insulating liquid improve (flash point, dielectric constant, breakdown voltage), while values of other parameters (density, kinematic viscosity, dielectric loss tangent) with an ester content of more than 10% in the mixture do not meet the requirements for mineral oils.


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