On the combination of the magnetotelluric and the geomagnetic depthsounding method for resolving an electrical conductivity increase at 400 km depth

1993 ◽  
Vol 20 (24) ◽  
pp. 2937-2940 ◽  
Author(s):  
Karsten Bahr ◽  
Nils Olsen ◽  
Thomas J. Shankland
2018 ◽  
Vol 69 (1) ◽  
pp. 155-159 ◽  
Author(s):  
Eugenia Eftimie Totu ◽  
Elena Voicila ◽  
Vlad Pistritu ◽  
Gheorghe Nechifor ◽  
Corina Marilena Cristache

In this paper, it is studied the influence of TiO2 nanoparticles content (0.2-5% wt:wt) on the electrical conductivities and the dielectric constants of poly (methyl methacrylate) (PMMA) nanocomposites used for 3D printing in dentistry. The nanocomposites films, which have been obtained applying the casting method followed by UV exposure, were mounted in a four electrodes cell for the electrochemical a.c. impedance analysis. The experimental data showed that both the dielectric constant and the electrical conductivity increase with increasing amounts of nano-TiO2 in nanocomposites. However, the change in the electrical conductivity is not significant for less 1% nano-titania added.


2019 ◽  
Vol 61 (10) ◽  
pp. 1743
Author(s):  
А.У. Шелег ◽  
В.Г. Гуртовой

The effect of various doses of electron irradiation on the dielectric constant and electrical conductivity of triple nonlinear AgGaSe2 crystals at different measuring field frequencies in the temperature range of 100-300 K has been investigated. It has been found that single-crystal irradiation leads to a dielectric constant decrease and an electrical conductivity significant increase. It is shown that the dielectric constant and electrical conductivity increase with an temperature increase. It has been established that AgGaSe2 crystals are characterized by the presence of several conductivity types. A significant frequency dispersion of the dielectric properties of the investigated crystals was found.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Kemal Yaman ◽  
Özer Taga

Thermal and electrical conductivity of unsaturated polyester resin with copper filler composite material are investigated both theoretically and experimentally. In the experiments, polyester matrix is combined with dendrite-shape copper to determine the effects of both filler size and content on thermal and electrical conductivity, respectively. It is observed that the increase in the concentration causes the thermal and electrical conductivity of composite mixture to grow up. It has also been observed that the both thermal and electrical conductivity increase with increasing filler particle size.


2010 ◽  
Vol 1267 ◽  
Author(s):  
John Chacha ◽  
S. Budak ◽  
Cydale Smith ◽  
Marcus Pugh ◽  
Kudus Ogbara ◽  
...  

AbstractThe performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2σT/K, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature and K is the thermal conductivity. ZT can be increased by increasing S, increasing σ, or decreasing K. We have prepared 100 alternating multi-nano layer of SiO2/SiO2+Cu superlattice films using the ion beam assisted deposition (IBAD). The 5 MeV Si ions bombardments have been performed at the different fluences using the AAMU Pelletron ion beam accelerator to make quantum clusters in the multi-layer superlattice thin films to decrease the cross plane thermal conductivity increase the cross plane Seebeck coefficient and cross plane electrical conductivity. To characterize the thermoelectric thin films before and after Si ion bombardments we have measured the cross-plane Seebeck coefficient, the cross-plane electrical conductivity, and the cross-plane thermal conductivity for different fluences.


2011 ◽  
Vol 687 ◽  
pp. 194-198 ◽  
Author(s):  
Chun Lin Fu ◽  
Huan Liao ◽  
Wei Cai ◽  
Chao Yang Zhang

Magnesium silicide (Mg2Si) has been identified a promising advanced thermoelectric material in temperature range from 300 to 700K. In order to understand thermoelectric properties of Co-doped magnesium silicide, the band structure and electronic density of states have been calculated using a first-principle pseudopotential method. It is shown that the band gap gradually decreases, at the same time degeneracy of the band and the density of states at the fermi level increase as the content of cobalt increases. It was properly predicted that the Seebeck coefficient and electrical conductivity increase, and thermal conductivity decreases as the content of cobalt increases.


1981 ◽  
Vol 7 ◽  
Author(s):  
J.S. Abel ◽  
H. Mazurek ◽  
D.R. Day ◽  
E.W. Maby ◽  
S.D. Senturia ◽  
...  

ABSTRACTIon-implantation can increase the electrical conductivity of the polymer poly (p-phenylene sulfide) (PPS) by ~ 14 orders of magnitude. This conductivity increase, which is stable under ambient conditions, is studied as a function of temperature, ion energy, fluence and species, using a novel technique, based on microelectronics processing, capable of accurately measuring conductivities as low as 10−10 (Ω-cm)−1. Mechanisms for the enhanced conductivity of PPS are discussed in relation to our measurements.


2017 ◽  
Vol 6 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Majeed Ali Habeeb ◽  
Leal Abdullah Hamza

The films prepared by casting method with different percentages of nano yttrium oxide (0, 3, 6, 9 and 12) wt%, where optical microscope images show the yttrium nanoparticles form a continuous network inside the polymers when the proportion of (12 wt%). FTIR spectra shows shift in peak position as well as change in shape and intensity, comparing with pure (PVA-PVP) films, this indicates decoupling between the corresponding vibrations of two polymers and yttrium nanoparticles, and we noted that there is a decrease in transmittance at increasing the proportion of yttrium oxide nanoparticles. Scanning electron microscopy shows the surface morphology of the (PVA-PVP-Y2O3) films many aggregates or chunks randomly distributed on the top surface, homogeneous and coherent. The absorbance increases with increase the weight percentages of nano yttrium oxide. The absorption coefficient, extinction coefficient, refractive index, real and imaginary parts of dielectric constants and optical conductivity are increasing with increase the weight percentages of yttrium oxide. The energy band gap decreases with increasing the weight percentages of yttrium oxide. The D.C electrical conductivity increase by increasing yttrium oxide concentrations and temperature. The activation energy decreases by increasing yttrium oxide concentrations. The resistance of the sensor decreased as humidity increased.


Sign in / Sign up

Export Citation Format

Share Document