Magnetic and Dielectric Properties of Barium Magnesium Hexaferrite Epoxy Resin Composite Film

2016 ◽  
Vol 1141 ◽  
pp. 54-56
Author(s):  
Chetna Chauhan ◽  
Reshma Nandotaria ◽  
Rajshree Jotania
Keyword(s):  
Room Temperature ◽  
Epoxy Composite ◽  
Resin Composite ◽  
Synthesis Method ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
Muffle Furnace ◽  
Epoxy Resin Composite ◽  
Suitable Amount ◽  
Solvent Free Synthesis

The W type barium magnesium hexaferrite powder with chemical composition BaMg2Fe16O27with CTAB surfactant was synthesized using solvent free synthesis method. The precursor was calcinated at 950 °C for 6 h in a muffle furnace and then slowly cooled to room temperature in order to obtain barium magnesium hexaferrite powder. The flexible epoxy thick film of Ba-Mg hexaferrite/epoxy composite was fabricated using suitable amount of hardener and curing agent. The field-dependent magnetic properties of the hexaferrite sample were investigated at room temperature using a vibrating sample magnetometer (VSM) with a maximum applied field of 15 kOe. The dielectric measurements were taken at room temperature within the frequency range to 100 Hz to 2 MHz.

Influence of Gamma Radiation on the Radiofrequency Dielectric Properties of Nigerian Crude Oil

2009 ◽  
Vol 62-64 ◽  
pp. 445-450
Author(s):  
O.D. Osahon ◽  
O.D. Nworgu
Keyword(s):  
Relaxation Time ◽  
Gamma Radiation ◽  
Crude Oil ◽  
Relative Permittivity ◽  
Room Temperature ◽  
Irradiation Time ◽  
Central Research ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
Dielectric Data

This paper examines the relative permittivity of irradiated and non-irradiated crude oil samples in the frequency range 0.1 – 100.0MHz and room temperature regulated at 25 ± 1oC. Samples of crude oil of mean specific gravity 0.780 ± 0.015 were irradiated for periods of two, four, six, eight and ten months respectively using a gamma radiation source (Cobalt 60) at a dose rate of 0.65mSv per hour. Dielectric measurements were made by using a Boonton RX meter type 250A admittance bridge manufactured by central research Laboratories, Inc, Red, Wing, Minnesota. Analysis of the resulting dielectric data revealed that both the irradiated and non-irradiated samples exhibited dielectric dispersion over the frequency range investigated. However, the relative permittivity values of the irradiated samples were found to be higher than those of the non-irradiated sample. This difference is understandable as it can be attributed to the ionization of atoms and weakening of molecular bonds in the irradiated samples. The increase in relative permittivity for the irradiated samples was observed to be time dependent as the longer the time of irradiation of sample the higher the value of its relative permittivity. Also, in this study, it was observed that the non-irradiated crude oil sample has longer relaxation time than the irradiated ones. The relaxation time decreases gradually with increasing irradiation time. This has physical significance on the basis of the molecular theory of matter and the fact that relaxation time is inversely proportional to relaxation frequency. These results are comparable with the work of other researchers for which similar trends have been observed.

Study of the Impact Viscosity of the Epoxy Composite Modified Technical Carbon

2020 ◽  
Vol 992 ◽  
pp. 285-289
Author(s):  
S.V. Vasiliev ◽  
Y.Y. Fedorov ◽  
A.V. Savvina
Keyword(s):  
Impact Strength ◽  
Carbon Black ◽  
Epoxy Resin ◽  
Epoxy Composite ◽  
Resin Composite ◽  
Filler Concentration ◽  
Technical Carbon ◽  
Epoxy Resin Composite ◽  
The Impact ◽  
Impact Viscosity

This article discusses effect of filler concentration on impact strength of an epoxy resin composite. The optimal ratio of resin and hardener is defined. Research of the effect of the concentration of the filler - carbon black P505 on the impact strength of a composite material based on epoxy resin ED-20 is made. According to the results of the study, it is shown that with an increase of concentration of the filler from P505 carbon black, the toughness decreases. Fractographic studies of the fracture surfaces of composites were also carried out, which indicate that the introduction of a filler leads to a decrease in the surface energy of destruction. Thus, studies of epoxy composite modified with technical carbon grade P505 showed a decrease in impact strength up to 4 times, depending on the increase in the mass fraction of the filler.

Characterization and dielectric properties of sodium fluoride doped talc

Clay Minerals ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 551-558
Author(s):  
S. Gümüştas ◽  
K. Köseoğlu ◽  
E. E. Yalçinkaya ◽  
M. Balcan
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Firing Temperature ◽  
Room Temperature ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
Detailed Characterization ◽  
Circuit Element

AbstractThe purpose of this paper is to determine the effect of NaF and firing temperature on the dielectric properties (dielectric constant and dielectric loss) of talc, which is used in the electrical and electronic industries as a circuit element. A detailed characterization of the samples was made by XRD, FTIR, SEM and TG-DTG methods. Dielectric measurements were performed in the frequency range from 1 MHz to 80 MHz at room temperature. The dielectric constant value increased with an increase in firing temperature due to the removal of polarizable compounds from the talc structure. The higher dielectric constant values were obtained by addition of NaF. The dielectric loss of NaF doped talc decreased with the increase of firing temperature and increased with the increase of the amount of NaF.

Experimental investigation and multi-objective optimization of multiple mechanical characteristics for chemically treated kenaf fibre reinforced epoxy composite using grey fuzzy logic

2021 ◽  
pp. 146442072110429
Author(s):  
Swati Gangwar ◽  
Neelesh Kumar Dubey ◽  
Vimal Kumar Pathak
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Epoxy Composite ◽  
Resin Composite ◽  
Fuzzy Optimization ◽  
Optimization Approach ◽  
Kenaf Fibre ◽  
Epoxy Resin Composite ◽  
Chemically Treated ◽  
Input Variables

In the present work, chemically treated kenaf fibre (10, 20 and 30 wt. %) reinforced epoxy resin composite formulations were fabricated using hand lay-up technique. The prepared composites were mechanically characterized using Taguchi L27 experimental design to examine the influence of varying kenaf fibre wt. %, NaOH concentration % for chemical treatment, and fibre immersion duration. The grey-fuzzy optimization approach was utilized for optimizing prepared formulations mechanical properties such as tensile strength, impact strength and flexural strength. Further, analysis of variance (ANOVA) tests and response graphs were utilized for delivering model significance and determining the percentage contribution of input variables. The NaOH concentration % was found to be most significant parameter followed by kenaf wt. % in providing best mechanical properties of chemically treated kenaf fibre reinforced epoxy composites.

Ferroelectric Ceramics Related to BaTiO3 for Z5U Multilayer Capacitors

2005 ◽  
Vol 492-493 ◽  
pp. 109-114 ◽  
Author(s):  
Laldja Taïbi-Benziada
Keyword(s):  
Room Temperature ◽  
Ferroelectric Ceramics ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
X Ray ◽  
Solid State Route ◽  
Displacive Phase Transition ◽  
Multilayer Capacitors ◽  
Diffraction Patterns ◽  
Conventional Solid State Route

Several pellets of general formula Ba1-xMx(Ti1-xLix)O3-3xF3x were prepared from BaTiO3, MF2 ( M = Ca, Sr, Ba or Pb ) and LiF powders then sintered by the conventional solid state route at 900 or 1000°C for 1, 2 or 4 hours. X-Ray powder diffraction patterns were collected at room temperature and SEM observations were carried out. Dielectric measurements were performed between 150 and 450K in the frequency range 50Hz - 40MHz. All the ceramics exhibit a very broad ferroelectric displacive phase transition in the temperature range 255K ≤ TC ≤ 328K.The ε' r - T curves and the values of tanδ are compatible with the Z5U class of capacitors. Furthermore, a Debye dielectric relaxation occurs in these oxifluorids in the frequency range 4MHz ≤fr ≤ 38.5MHz.

scholarly journals Photothermal, Photoelectric, and Photothermoelectric Effects in Bi-Sb Thin Films in the Terahertz Frequency Range at Room Temperature

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 76
Author(s):  
Mikhail K. Khodzitsky ◽  
Petr S. Demchenko ◽  
Dmitry V. Zykov ◽  
Anton D. Zaitsev ◽  
Elena S. Makarova ◽  
...  
Keyword(s):  
Thin Films ◽  
Terahertz Radiation ◽  
Room Temperature ◽  
Voltage Drop ◽  
Radiation Detection ◽  
Radiation Detectors ◽  
Thz Radiation ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range

The terahertz frequency range is promising for solving various practically important problems. However, for the terahertz technology development, there is still a problem with the lack of affordable and effective terahertz devices. One of the main tasks is to search for new materials with high sensitivity to terahertz radiation at room temperature. Bi1−xSbx thin films with various Sb concentrations seem to be suitable for such conditions. In this paper, the terahertz radiation influence onto the properties of thermoelectric Bi1−xSbx 200 nm films was investigated for the first time. The films were obtained by means of thermal evaporation in vacuum. They were affected by terahertz radiation at the frequency of 0.14 terahertz (THz) in the presence of thermal gradient, electric field or without these influences. The temporal dependencies of photoconductivity, temperature difference and voltage drop were measured. The obtained data demonstrate the possibility for practical use of Bi1−xSbx thin films for THz radiation detection. The results of our work promote the usage of these thermoelectric materials, as well as THz radiation detectors based on them, in various areas of modern THz photonics.

scholarly journals Dielectric Spectroscopy Analysis of Liquid Crystals Recovered from End-of-Life Liquid Crystal Displays

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2873
Author(s):  
Ana Barrera ◽  
Corinne Binet ◽  
Frédéric Dubois ◽  
Pierre-Alexandre Hébert ◽  
Philippe Supiot ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
End Of Life ◽  
Room Temperature ◽  
Liquid Crystal Displays ◽  
Dielectric Anisotropy ◽  
Frequency Range ◽  
Spectroscopy Analysis ◽  
Diamond Nanoparticles ◽  
Nematic Phases ◽  
Universal Law

In the present work, the dielectric properties of recycled liquid crystals (LCs) (non-purified, purified, and doped with diamond nanoparticles at 0.05, 0.1, and 0.2 wt%) were investigated. The studied LC mixtures were obtained from industrial recycling of end-of-life LC displays presenting mainly nematic phases. Dielectric measurements were carried out at room temperature on a frequency range from 0.1 to 106 Hz using an impedance analyzer. The amplitude of the oscillating voltage was fixed at 1 V using cells with homogeneous and homeotropic alignments. Results show that the dielectric anisotropy of all purified samples presents positive values and decreases after the addition of diamond nanoparticles to the LC mixtures. DC conductivity values were obtained by applying the universal law of dielectric response proposed by Jonscher. In addition, conductivity of the doped LC mixtures is lower than that of the undoped and non-purified LC.

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