scholarly journals GEOMAGNETIC INDUCTION RESPONSES OF ANISOTROPIC CONDUCTING MANTLE

2014 ◽  
Vol 55 (10) ◽  
Keyword(s):  
Geomagnetic Induction ◽  
Anisotropic Conducting

Inversion of the geomagnetic induction problem

1970 ◽  
Vol 315 (1521) ◽  
pp. 185-194 ◽  
Keyword(s):  
Frequency Spectrum ◽  
Real Data ◽  
Real Analytic Function ◽  
Numerical Application ◽  
Geomagnetic Induction ◽  
Induction Equation ◽  
Real Analytic ◽  
Principle Of Causality ◽  
Magnetic Potentials ◽  
Magnetic Induction Equation

An algorithm has been found for inverting the problem of geomagnetic induction in a con­centrically stratified Earth. It determines the (radial) conductivity distribution from the frequency spectrum of the ratio of internal to external magnetic potentials of any surface harmonic mode. The derivation combines the magnetic induction equation with the principle of causality in the form of an integral constraint on the frequency spectrum. This algorithm generates a single solution for the conductivity. This solution is here proved unique if the conductivity is a bounded, real analytic function with no zeros. Suggestions are made regarding the numerical application of the algorithm to real data.

scholarly journals Earth conductivity structures and their effects on geomagnetic induction in pipelines

2007 ◽  
Vol 25 (1) ◽  
pp. 207-218 ◽  
Author(s):  
P. A. Fernberg ◽  
C. Samson ◽  
D. H. Boteler ◽  
L. Trichtchenko ◽  
P. Larocca
Keyword(s):  
Geoelectric Field ◽  
Geomagnetically Induced Currents ◽  
Geomagnetic Induction ◽  
Natural Gas Pipeline ◽  
Geological Conditions ◽  
Line Theory ◽  
Spatially Variant ◽  
Tectonic Terranes ◽  
The Impact ◽  
Earth Conductivity

Abstract. Anomalous, large pipe-to-soil potentials (PSP) have been observed along a natural gas pipeline in eastern Ontario, Canada, where there is a major geological contact between the highly resistive rocks of the Precambrian Shield to the west and the more conductive Paleozoic sediments to the east. This study tested the hypothesis that large variations of PSP are related to lateral changes of Earth conductivity under the pipeline. Concurrent and co-located PSP and magnetotelluric (MT) geophysical data were acquired in the study area. Results from the MT survey were used to model PSP variations based on distributed-source transmission line theory, using a spatially-variant surface geoelectric field. Different models were built to investigate the impact of different subsurface features. Good agreement between modelled and observed PSP was reached when impedance peaks related to major changes of subsurface geological conditions were included. The large PSP could therefore be attributed to the presence of resistive intrusive bodies in the upper crust and/or boundaries between tectonic terranes. This study demonstrated that combined PSP-MT investigations are a useful tool in the identification of potential hazards caused by geomagnetically induced currents in pipelines.

Geomagnetic induction anomalies along the hyderabad—kalingapatnam profile

1974 ◽  
Vol 24 (4) ◽  
pp. 343-350 ◽  
Author(s):  
B.J. Srivastava ◽  
D.S. Bhaskara Rao ◽  
S.N. Prasad
Keyword(s):  
Geomagnetic Induction

Understanding Anisotropic Conducting Adhesive Behaviour

1995 ◽  
Vol 12 (2) ◽  
pp. 55-59 ◽  
Author(s):  
J.M. Goward ◽  
D.C. Whalley ◽  
D.J. Williams
Keyword(s):  
Anisotropic Conducting

Electrical conductivity of carbon nanotube/polypropylene composites prepared through microlayer extrusion technology

2017 ◽  
Vol 37 (8) ◽  
pp. 795-804 ◽  
Author(s):  
Changjin Li ◽  
Zhiwei Jiao ◽  
Liangzhao Xiong ◽  
Weimin Yang
Keyword(s):  
Electrical Conductivity ◽  
Polymer Matrix ◽  
Rotation Speed ◽  
Mapping Method ◽  
Degree Of Crystallinity ◽  
Polypropylene Composites ◽  
Multilayered Composites ◽  
Promising Application ◽  
Anisotropic Conducting ◽  
Extrusion Technology

Abstract The morphological distribution of carbon nanotubes (CNTs) in polymer matrix has a crucial impact on the performance of CNT-filled polymer composites. A novel microlayer extrusion technology used in the dispersion and orientation of CNTs was proposed, and polypropylene (PP)/multiwalled CNT (MWCNT) composites with different numbers of layers were prepared with it. The MWCNT dispersion was investigated by scanning electron microscopy and Raman mapping method, and the MWCNT orientation was quantified by Raman spectroscopy. The influences of the dispersion and orientation of MWCNTs on the electrical conductivity and crystallization behavior of the composites were investigated. The results showed that the anisotropic conducting properties of the multilayered composites varied distinguishably with the increase of layer numbers and rotation speed. Furthermore, the degree of crystallinity of PP increased when the layer number increased from 1 to 729. All of these results suggest that with the increase of the layer numbers and the rotation speed, the dispersion and orientation of MWCNTs in PP matrix improve greatly. Overall, we provide an efficient and practical approach to control the dispersion and orientation of CNT in polymer matrix, which has a promising application prospect in the field of plastic processing.

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