scholarly journals A 2D Magneto-Acousto-Electrical Tomography Method to Detect Conductivity Variation Using Multifocus Image Method

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2373 ◽  
Author(s):  
Ming Dai ◽  
Xin Chen ◽  
Tong Sun ◽  
Lingyao Yu ◽  
Mian Chen ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Chirp Pulse ◽  
Image Method ◽  
Electrical Tomography ◽  
Conductivity Distribution ◽  
Conductivity Variation ◽  
Shaped Hole ◽  
Imaging Resolution ◽  
Single Focus ◽  
Pulse Stimulation

As magneto-acoustic-electrical tomography (MAET) combines the merits of high contrast and high imaging resolution, and is extremely useful for electrical conductivity measurement, so it is expected to be a promising medical imaging modalities for diagnosis of early-stage cancer. Based on the Verasonics system and the MC600 displacement platform, we designed and implemented a MAET system with a chirp pulse stimulation (MAET-CPS) method and a focal probe was utilized for stepscan focus excitation to enhance the imaging resolution. The relevant experiments were conducted to explore the influence of excitation positions of the single-focus point, and the effect of the excitation position on the amplitudes of the conductivity variation was clearly demonstrated. In order to take advantage of the merits of multifocus imaging, we firstly proposed a single focus MAET system with a chirp pulse stimulation (sfMAET-CPS) method and a multifocus MAET system with a chirp pulse stimulation (mfMAET-CPS) method for high-resolution conductivity imaging, and a homogenous gelatin phantom with a cuboid-shaped hole was used to investigate the accuracy of mfMAET-CPS. Comparative experiments were carried out on the same uniform phantom by the sfMAET-CPS and the mfMAET-CPS, respectively. The results showed that: (1) the electrical conductivity distributions of the homogenous phantom with a cuboid-shaped hole were detected by the sfMAET-CPS but were easily affected by the focal point, which demonstrated that the sfMAET-CPS had a low imaging resolution. (2) Compared with the sfMAET-CPS, the imaging effect of the mfMAET-CPS was much better than that of the sfMAET-CPS. (3) A linear interpolation algorithm was used to process the 2D conductivity distribution; it increased the smoothness of the conductivity distribution and improved the imaging effect. The stepscan focus excitation and the linearly frequency-modulated theory provide an alternative scheme for the clinical application of MAET.

Investigation of dryland salinity using the electrical image method

Soil Research ◽  
1999 ◽  
Vol 37 (4) ◽  
pp. 623 ◽  
Author(s):  
R. I. Acworth
Keyword(s):  
Electrical Conductivity ◽  
Salt Content ◽  
Image Method ◽  
Dryland Salinity ◽  
Conductivity Variation ◽  
South Wales ◽  
Electrical Imaging ◽  
Profile Line ◽  
Conductivity Anomalies ◽  
A Site

Electrical imaging is a 2-dimensional investigation method that can be used to rapidly determine subsurface conductivity variation. In dryland salinity studies, electrical imaging is used to define the vertical extent of high electrical conductivity zones first identified using electromagnetic (EM) profiling equipment. Field techniques are described using 25 or 50 electrodes, connected to a resistance meter by a multi-core cable, to obtain images at a variety of electrode separations. The model of electrical conductivity variation obtained by an inversion of the field data is shown to agree very well with the results of detailed field investigations, including data from soil sampling, 1 : 5 extract analysis, and borehole electrical conductivity logging. Results are described from the Liverpool Plains at Yarramanbah Creek and Round Island, where a thick sequence of smectite clay overlies sands and gravels. The image clearly identifies zones of high salt content in the clay which have been sampled and logged using borehole measurements of electrical conductivity. Results are also described from a dryland salinity area in the upper part of Dicks Creek catchment on the Southern Tablelands of New South Wales. These data show the extent of clay overlying bedrock and correlate very well with the results of 1 : 5 extract analysis from shallow piezometers along the profile line. Electrical imaging is an appropriate follow-up method for the investigation of electrical conductivity anomalies first identified by EM profiling and is advisable before drilling at a site to optimise the location of piezometers.

Equivalent images derived from very-low-frequency (VLF) profile data

Geophysics ◽  
2005 ◽  
Vol 70 (3) ◽  
pp. G43-G50 ◽  
Author(s):  
Laust B. Pedersen ◽  
Michael Becken
Keyword(s):  
Electrical Conductivity ◽  
Low Frequency ◽  
Rate Of Change ◽  
Single Frequency ◽  
Depth Information ◽  
Profile Data ◽  
Conductivity Distribution ◽  
Very Low Frequency ◽  
Current Distributions ◽  
Clay Lenses

We describe the implementation of a new fast imaging technique for filtering very-low-frequency (VLF) data measured on profiles into corresponding equivalent current systems in the earth. Single-frequency VLF data using magnetic measurements alone are often used to delineate lateral changes in electrical conductivity, e.g., fracture zones in crystalline terrains or changes in lithology in the sedimentary cover. Here, an attempt is made to add depth information to the conductivity distribution by realizing that the single-frequency VLF profile data contain information about (1) the background medium through their decay away from the conductors, (2) the position, and (3) the depth of the dominating conductors through the relative contribution of in-phase and quadrature components to the VLF anomaly in addition to the rate of change of the anomaly close to the conductors. Synthetic data from a model containing a shallow and a deeper conductor are filtered to show that the estimated current distributions coincide well with the horizontal position of the conductors, but even they provide some smeared images of the depth distribution of the conductors. A comparison with models obtained from regularized inversion of the same data shows good correspondence. The VLF field data from an area with clay lenses overlying wet sand and crystalline basement are filtered into current distributions that grossly mimic the electrical conductivity distribution of the clay lenses as obtained from radiomagnetotelluric measurements along the same profile.

A "SELF-CONSISTENT SOLUTION" METHOD FOR DETERMINING THE ELECTRICAL CONDUCTIVITY IN THE SUBSURFACE REGIONS OF THE EARTH

1964 ◽  
Vol 1 (3) ◽  
pp. 206-210
Author(s):  
Tomiya Watanabe
Keyword(s):  
Electrical Conductivity ◽  
Boundary Conditions ◽  
Solution Method ◽  
Magnetic Method ◽  
Entire Surface ◽  
Conductivity Distribution ◽  
The Earth ◽  
Self Consistent ◽  
Consistent Solution ◽  
The Magnetic Field

The assumptions on which the so-called magneto-telluric method to determine the subsurface conductivity of the earth is based are examined and it is shown how the method can be revised to get rid of those assumptions which are not necessarily legitimate. The principle of this revised or generalized magneto-telluric method is that the magnetic and telluric field components which observation can provide over the entire surface of the earth are more than sufficient viewed as boundary conditions to determine the electromagnetic field inside the earth with a prescribed conductivity distribution and, therefore, the extra boundary conditions can be consistent with each other only by the correctly prescribed (or chosen) distribution of electrical conductivity. The purely magnetic method to determine the conductivity, which relies on the assumption that the magnetic field in space above the surface of the earth, is a potential field, is also revised to free it of the assumption which, does not hold true unconditionally.

scholarly journals Electrical Conductivity Distribution in Detonating Benzotrifuroxane

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Nataliya Satonkina ◽  
Alexander Ershov ◽  
Alexey Kashkarov ◽  
Anatoly Mikhaylov ◽  
Eduard Pruuel ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Conductivity Distribution

scholarly journals Electrospray characteristics of aqueous KCl solutions with various electrical conductivities

2018 ◽  
Author(s):  
Sahand Faraji ◽  
Behnam Sadri ◽  
Babak Vajdi Hokmabad ◽  
Esmaeil Esmaeilzadeh ◽  
Navid Jadidoleslam
Keyword(s):  
Electrical Conductivity ◽  
Experimental Study ◽  
Stainless Steel ◽  
High Voltage ◽  
Room Temperature ◽  
High Voltage Electrode ◽  
Flow Rates ◽  
Conductivity Variation ◽  
Electrical Conductivities ◽  
Stainless Steel Ring

In the present experimental study, the effects of electrical conductivity on electrospraying procedure are investigated.A metallic nozzle with 600 m ID as high voltage electrode and a stainless steel ring as a groundelectrode were employed. Experiments were carried out in still room temperature. Four different aqueous KClsolutions were sprayed in various high voltages and flow rates. Results confirm that spraying modes changeswith conductivity variation. For forming a cone shape, emerging from the nozzle, required applied electric fielddecreases with conductivity increasing. Results also revealed that conductivity of dispersed solution acts a mainrole on forming and elongation of the cones in electrospraying procedure. The size and velocity of emanateddroplets are also investigated in order to gaining some insight to the electrospraying phenomenon.

Continuous Electrical Conductivity Variation in M3(Hexaiminotriphenylene)2 (M = Co, Ni, Cu) MOF Alloys

2020 ◽  
Vol 142 (28) ◽  
pp. 12367-12373 ◽  
Author(s):  
Tianyang Chen ◽  
Jin-Hu Dou ◽  
Luming Yang ◽  
Chenyue Sun ◽  
Nicole J. Libretto ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Conductivity Variation

scholarly journals Research on Factors Affecting the Imaging Resolution of Magneto–Acousto–Electrical Tomography

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 203457-203467
Author(s):  
Ming Dai ◽  
Jinfeng Xu ◽  
Tong Sun ◽  
Chrisopher Qian ◽  
Mian Chen ◽  
...  
Keyword(s):  
Electrical Tomography ◽  
Factors Affecting ◽  
Imaging Resolution
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