Measurement of electrical conductivity of 0.001 mol NaCl solution under high pressures

1997 ◽  
Vol 42 (18) ◽  
pp. 1563-1566 ◽  
Author(s):  
Zheng Haifei ◽  
Xie Hongsen ◽  
Xu Yousheng ◽  
Song Maoshuang ◽  
Guo Jie ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
High Pressures ◽  
Nacl Solution

scholarly journals Elastic wave velocity and electrical conductivity in a brine-saturated rock and microstructure of pores

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Tohru Watanabe ◽  
Miho Makimura ◽  
Yohei Kaiwa ◽  
Guillaume Desbois ◽  
Kenta Yoshida ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Elastic Wave ◽  
Wave Velocity ◽  
High Pressures ◽  
Seismic Velocity ◽  
Volume Fraction ◽  
Elastic Wave Velocity ◽  
Fluid Volume ◽  
Sem Observation ◽  
Wide Aperture

AbstractElastic wave velocity and electrical conductivity in a brine-saturated granitic rock were measured under confining pressures of up to 150 MPa and microstructure of pores was examined with SEM on ion-milled surfaces to understand the pores that govern electrical conduction at high pressures. The closure of cracks under pressure causes the increase in velocity and decrease in conductivity. Conductivity decreases steeply below 10 MPa and then gradually at higher pressures. Though cracks are mostly closed at the confining pressure of 150 MPa, brine must be still interconnected to show observed conductivity. SEM observation shows that some cracks have remarkable variation in aperture. The aperture varies from ~ 100 nm to ~ 3 μm along a crack. FIB–SEM observation suggests that wide aperture parts are interconnected in a crack. Both wide and narrow aperture parts work parallel as conduction paths at low pressures. At high pressures, narrow aperture parts are closed but wide aperture parts are still open to maintain conduction paths. The closure of narrow aperture parts leads to a steep decrease in conductivity, since narrow aperture parts dominate cracks. There should be cracks in various sizes in the crust: from grain boundaries to large faults. A crack must have a variation in aperture, and wide aperture parts must govern the conduction paths at depths. A simple tube model was employed to estimate the fluid volume fraction. The fluid volume fraction of 10−4–10−3 is estimated for the conductivity of 10−2 S/m. Conduction paths composed of wide aperture parts are consistent with observed moderate fluctuations (< 10%) in seismic velocity in the crust.

Dehydration and decomposition of pyrophyllite at high pressures: electrical conductivity and X-ray diffraction studies to 5 GPa

1997 ◽  
Vol 34 (6) ◽  
pp. 875-882 ◽  
Author(s):  
Tara L. Hicks ◽  
Richard A. Secco
Keyword(s):  
Electrical Conductivity ◽  
South African ◽  
Pressure Dependence ◽  
High Pressures ◽  
Ionic Conduction ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Dependence Of Conductivity

The dehydration and decomposition of South African pyrophyllite were studied in the pressure range 2.5–5.0 GPa and in the temperature (T) range 295–1473 K using both in situ electrical conductivity measurements and X-ray diffraction studies on the recovered samples. Activation energies for conduction (Qc) vary in the range 0.02–0.07 eV for T ≤ 500 K where the dominant conduction mode is electronic, and Qc is in the range 1.10–1.28 eV for T ≥ 500 K where ionic conduction dominates. Abrupt changes in the isobaric temperature dependence of conductivity mark the onset of dehydration and subsequent decomposition into kyanite plus quartz–coesite. At 2.5 GPa, South African pyrophyllite forms the dehydroxylate phase at 760 K with a pressure dependence of ~30 K/GPa and complete decomposition follows at 1080 K with a pressure dependence of ~41 K/GPa. The resulting pressure–temperature phase diagram is in very good agreement with many previous studies at 1 atm (101.325 kPa).

Micromachined Electrical Conductivity Probe for RF Ablation of Tumors

2005 ◽  
Author(s):  
Ming Yi ◽  
Hrishikesh V. Panchawagh ◽  
Roop L. Mahajan ◽  
Zhengjun Liu ◽  
S. Nahum Goldberg
Keyword(s):  
Electrical Conductivity ◽  
Saline Water ◽  
Effective Area ◽  
Substrate Material ◽  
Rf Ablation ◽  
Nacl Solution ◽  
In Vivo Tests ◽  
Probe Calibration ◽  
The One

RF ablation is an important technique in cancer treatment. It has been proposed that the effective area treated via RF ablation can be increased by increasing the local electrical conductivity. This is achieved by injection of NaCl solution into the tissue. For an accurate and effective RF ablation treatment using this new method, it is necessary to measure the local electrical conductivity, which varies spatially due to diffusion of sodium chloride. In this paper, we propose a micro probe to measure the local tissue electrical conductivity. The probe consists of two in-plane miniature electrodes separated by a small gap. When the electrodes are in contact with the tissue, the electrical resistance across them can be used to calculate the electrical conductivity. The probe is fabricated by standard photolithography techniques. The substrate material is polyimide and the electrodes are made of gold. A four-electrode probe is used to calibrate the new electrical conductivity micro probe using different concentrations of saline water. The resistance measurements are carried out using an impedance analyzer on different frequencies. The frequency of choice for RF ablation of tumors is 500k Hz and is the one selected for calibration and testing. The micro-probe calibration is then verified by measuring electrical conductivity of a phantom and comparing it with the result measured by the four-electrode probe. Finally, some in vivo tests are performed and the results are compared with literate data.

scholarly journals The effect of steam quality on the electrical behavior of steam‐flooded sands: A laboratory study

Geophysics ◽  
1995 ◽  
Vol 60 (4) ◽  
pp. 998-1006 ◽  
Author(s):  
David B. Butler ◽  
Rosemary J. Knight
Keyword(s):  
Electrical Conductivity ◽  
Laboratory Study ◽  
Steam Injection ◽  
Electrical Behavior ◽  
Nacl Solution ◽  
Laboratory Measurements ◽  
Steam Quality ◽  
High Quality ◽  
Local Conductivity ◽  
Over Time

Laboratory measurements of the effects of steam injection on the electrical conductivity of sands can aid in the interpretation of electrical surveys used to monitor subsurface steam‐injection projects. The effect of variations in injected steam quality was measured in the experiments presented here. The injection of low‐quality steam, boiled from a 0.01 mol/L NaCl solution, into clean sand saturated with 0.01 mol/L NaCl, resulted in a net decrease in conductivity and a constant equilibrium conductivity in the steam zone. The injection of high‐quality steam, using the same saturating and injection salinities, caused the conductivity to first drop to a minimum and then to increase to an equilibrium value similar to that seen in the low‐quality injection. The local conductivity minimum deepened with time and traveled with the steam front. The appearance of the conductivity minimum at the steam front can be attributed to the formation of a dilution bank, which temporarily decreases the local salinity. The extent of the dilution increases with time, resulting in the decrease of the conductivity over time. The conductivity then increases as injected salt moves through the sand. The steam quality controls the appearance of this minimum because it determines the relative speeds of the steam front and the steam liquid: a minimum will not occur if the steam front moves more slowly than the steam liquid.

scholarly journals THE ELECTRICAL CONDUCTIVITY OF PURE PROTOPLASM

1925 ◽  
Vol 7 (3) ◽  
pp. 327-330 ◽  
Author(s):  
S. C. Brooks
Keyword(s):  
Electrical Conductivity ◽  
Sea Water ◽  
Slime Mold ◽  
Nacl Solution ◽  
Surrounding Fluid

The electrical conductivity of the plasmodium of the slime-mold Brefeldia maxima (Fr.) Rost., which constitutes practically pure protoplasm, was found to be approximately equivalent under normal conditions to that of a 0.00145 N NaCl solution, and about 2.8 times that of the liquid in contact with which it developed. When bathed in 1 per cent sea water, the conductivity was much increased, becoming greater than that of the surrounding fluid. These preliminary tests are in agreement with the supposition that the protoplasm is permeable to and in equilibrium with its environment in so far as electrolytes are concerned.

Electrical conductivity and amorphization of Sc2(WO4)3 at high pressures and temperatures

2002 ◽  
Vol 63 (3) ◽  
pp. 425-431 ◽  
Author(s):  
R.A. Secco ◽  
H. Liu ◽  
N. Imanaka ◽  
G. Adachi ◽  
M.D. Rutter
Keyword(s):  
Electrical Conductivity ◽  
High Pressures ◽  
High Pressures And Temperatures
Sign in / Sign up

Export Citation Format

Share Document