INDUCED POLARIZATION IN ELECTROLYTE SATURATED EARTH PLUGS

Geophysics ◽  
1961 ◽  
Vol 26 (2) ◽  
pp. 205-210 ◽  
Author(s):  
J. H. Henkel ◽  
T. C. Collins
Keyword(s):  
Time Dependence ◽  
Electric Dipole ◽  
Concentration Polarization ◽  
Solution Concentration ◽  
Induced Polarization ◽  
Relaxation Theory ◽  
Clay Particles ◽  
Formation Resistivity ◽  
Current Flows ◽  
Dipole Polarization

This paper describes the results of some studies of the dependence of induced polarization and of the formation resistivity factor upon solution concentration in saturated porous plugs. Two theories based upon two different simple models are developed. The first treats induced polarization as an electric dipole polarization occurring at the surface of clay particles. It is a relaxation theory that does not lead to results agreeable with experiments. The second theory treats induced polarization as a concentration polarization which is induced at solution‐clay surfaces when current flows across the surfaces. The second theory is more successful than the first in two ways: (1) it leads to a time dependence more consistent with the experimental decays; (2) it leads to equations involving the resistivity of the saturating solution [Formula: see text] which are also more consistent with experiments.

On modeling a well casing for resistivity and induced polarization

Geophysics ◽  
1984 ◽  
Vol 49 (11) ◽  
pp. 2061-2063 ◽  
Author(s):  
James R. Wait
Keyword(s):  
Electrical Properties ◽  
Electric Dipole ◽  
Free Space ◽  
Eddy Currents ◽  
Interfacial Polarization ◽  
Induced Polarization ◽  
Mutual Impedance ◽  
The Earth ◽  
Horizontal Electric Dipole ◽  
Displacement Currents

In a previous communication I proposed an analytical model to simulate the electromagnetic (EM) and induced polarization (IP) response of a metal well casing (Wait, 1983). To facilitate the analysis, the earth was idealized as a homogeneous conducting half‐space of electrical properties (σ, ε, μ). The well casing was represented as a filamental vertical conductor of semiinfinite length that was characterized by a series axial impedance to account for eddy currents and interfacial polarization. A further basic simplification was to neglect displacement currents in the air; this was justified when all significant distances were small compared with the free‐space wavelength. Initially, the source was taken to be a horizontal electric dipole or current element I ds on the air‐earth interface. By integration of the results, the mutual impedance between two grounded circuits could be ascertained. In the absence of the vertical conductor (i.e., the well casing) the results reduced to those given by Sunde (1968) and Ward (1967).

Effect of Operating Parameters on the DMFC Performance

2004 ◽  
Vol 2 (2) ◽  
pp. 81-85 ◽  
Author(s):  
Guo-Bin Jung ◽  
Ay Su ◽  
Cheng-Hsin Tu ◽  
Fang-Bor Weng
Keyword(s):  
Concentration Polarization ◽  
Solution Concentration ◽  
Open Circuit ◽  
Methanol Solution ◽  
Operating Conditions ◽  
Cell Performance ◽  
Membrane Electrode ◽  
Membrane Thickness ◽  
Methanol Crossover ◽  
Cell Temperature

Methanol crossover largely affects the efficiency of power generation in the direct methanol fuel cell. As the methanol crosses over through the membrane, the methanol oxidizes at the cathode, resulting in low fuel utilization and in a serious overpotential loss. In this study, the commercial membrane electrode assemblies (MEAs) are investigated with different operating conditions such as membrane thickness, cell temperature, and methanol solution concentration. The effects of these parameters on methanol crossover and power density are studied. With the same membrane, increasing the cell temperature promotes the cell performance as expected, and the lower methanol concentration causes the concentration polarization effects, thus resulting in lower cell performance. Although higher methanol solution concentration can overcome the concentration polarization, a serious methanol crossover decreases the cell performance at high cell temperature. In this study, the open circuit voltage (OCV) is inversely proportional to methanol solution concentration, and is proportional to membrane thickness and cell temperature. Although increasing membrane thickness lowers the degree of methanol crossover, on the other hand, the ohmic resistance increases simultaneously. Therefore, the cell performance using Nafion 117 as membrane is lower than that of Nafion 112. In addition, the performance of the MEA made in our laboratory is higher than the commercial product, indicating the capability of manufacturing MEA is acceptable.

scholarly journals Abnormal Influence of Ions on Shock-Induced Polarization in Binary Electrolytes

2008 ◽  
Vol 45 (1) ◽  
pp. 63-70
Author(s):  
B. Martuzans ◽  
Yu. Skryl
Keyword(s):  
Mole Fraction ◽  
Induced Polarization ◽  
Small Concentration ◽  
High Conductivity ◽  
Polarization Current ◽  
Direct Contribution ◽  
Indirect Influence ◽  
Dissolved Ions ◽  
Dipole Polarization

Abnormal Influence of Ions on Shock-Induced Polarization in Binary ElectrolytesThe study is aimed at modeling the shock-induced polarization of liquid superdiluted binary (KF) electrolytes at low (<10-4mole fraction) concentration of K+and F-ions (i.e. not making direct contribution to the polarization current). It is supposed that at such a small concentration of electrolyte only the dipole polarization of water occurs, while the indirect influence of ions is expressed in its reduced conductivity in the compressed region at increasing concentration of the dissolved ions. In the authors' opinion, this influence is connected with suppression of the transition of water into high-conductivity phase by the ions of electrolyte.

scholarly journals Rare earth conversion coatings grown on AA6061 aluminum alloys. Corrosion studies.

2017 ◽  
Vol 58 (4) ◽  
Author(s):  
Miguel Antonio Domínguez-Crespo ◽  
Silvia Beatriz Brachetti-Sibaja ◽  
Aidé Minerva Torres-Huerta ◽  
Wencel De La Cruz-Hernández
Keyword(s):  
Rare Earth ◽  
Immersion Time ◽  
Concentration Polarization ◽  
Protective Coatings ◽  
Bath Temperature ◽  
Solution Concentration ◽  
Cathodic Process ◽  
Spontaneous Deposition ◽  
Corrosion Studies ◽  
Tafel Slopes

The present work is aimed to investigate the corrosion resistance of rare earth (RE) protective coatings deposited by spontaneous deposition on AA6061 aluminum alloy substrates. Coatings were deposited from water-based Ce(NO<sub>3</sub>)<sub>3</sub> and La(NO<sub>3</sub>)<sub>3</sub> solutions by varying parameters such as rare earth solution concentration, bath temperature and immersion time. The values of the Tafel slopes indicate that the cathodic process is favored by concentration polarization rather than activation polarization.

Investigation of the power generation performance of a stack by reverse electrodialysis and its influencing factors

2021 ◽  
pp. 1-9
Author(s):  
Mei Li ◽  
Yiwei Wang ◽  
Jiabin Guo ◽  
Xiaoliang Li ◽  
Pengcheng Guo
Keyword(s):  
Power Generation ◽  
Flow Rate ◽  
Power Output ◽  
Concentration Polarization ◽  
Solution Concentration ◽  
Generation Process ◽  
Cell Pair ◽  
Ohmic Resistance ◽  
Pair Number ◽  
Membrane Type

Abstract This paper presents an experimental study on the performance of a RED stack for SELEMION, ASTOM and FUJI membranes with the cell pair number from 3 to 15 and flow rate from 5 to 60 L/h over a wide solution concentration range from 1 to 120 g/L. DC and AC measurements are employed to identify quantatively the contribution of ohmic and non-ohmic resistances to the stack resistance and then, the power output is predicted theoretically. The results show that the ohmic resistance dominates in the stack resistance and accounts for about 90%. The factors such as the membrane type, cell pair, solution concentration and flow rate have a considerable impact on power generation process of RED. Especially, simultaneous increasing the HC and LC solution concentrations is more conducive to suppressing the concentration polarization when compared with increasing LC solution concentration alone. Although the concentration polarization maintains declining with the increase in flow rate, the flow rate should not be too large in order to harvest the highest power output by reason of serious tangential flow at higher flow rates. The optimal performance of RED stack is obtained when SELEMION membranes are used with cell pairs of 5, HC-LC solution concentration of 120-4 g/L and feed flow rate of 20 L/h.

Synthesis and EMW absorbing properties of nano SiC modified PDC–SiOC

2016 ◽  
Vol 4 (25) ◽  
pp. 5962-5969 ◽  
Author(s):  
Wenyan Duan ◽  
Xiaowei Yin ◽  
Fang Ye ◽  
Quan Li ◽  
Meikang Han ◽  
...  
Keyword(s):  
Phase Composition ◽  
Electric Dipole ◽  
Silicon Oxycarbide ◽  
Strong Absorption ◽  
Interfacial Scattering ◽  
Dipole Polarization

Nano SiC modified silicon oxycarbide (n-SiC/SiOC) ceramics had special microstructure and phase composition that can lead to electric dipole polarization and interfacial scattering which eventually resulted in the strong absorption capability of n-SiC/SiOC.

THE EFFECT OF SONDE POSITION IN THE HOLE ON RESPONSES OF RESISTIVITY LOGGING TOOLS

Geophysics ◽  
1977 ◽  
Vol 42 (3) ◽  
pp. 642-654 ◽  
Author(s):  
S. C. Gianzero ◽  
R. Rau
Keyword(s):  
Current Distribution ◽  
Field Experiments ◽  
Low Frequency ◽  
The Other ◽  
Test Tank ◽  
Other Hand ◽  
Formation Resistivity ◽  
Current Flows ◽  
Resistivity Logging

Theoretical relations exist in the literature for calculating the responses of electrode‐type resistivity logging tools when they are centered in the wellbore and the formations are thick and homogeneous (Fok, 1933; Stefanesco et al., 1929–32). These analyses are usually restricted to devices using dc or low‐frequency surveying currents, and they generally make use of the approximation of point electrodes. An analysis has also been made comparing the responses of such tools in anisotropic and isotropic formations (Kunz and Moran, 1958). In this paper, relations are derived for calculating the responses of electrode‐type logging tools when the sonde is not centered in the wellbore. Although similar relations could be applied to tilted sondes, the discussion in this paper is mainly restricted to the simple eccentered case in which the axis of the sonde is parallel to the axis of the hole. As will be shown, eccentering has a comparatively small effect on the responses of a normal device. On the other hand, certain types of focused‐log devices, in which a large proportion of the focusing current flows parallel to the hole, may exhibit an appreciable eccentering effect; this is particularly true when the contrast between formation resistivity and hole‐fluid resistivity is large. Spherically‐Focused‐Log (SFL*) resistivity devices (Schuster et al., 1971) have this type of current distribution, and, depending on electrode spacings, they may be appreciably influenced by eccentering. The applications shown in this paper will largely be done from SFL computations and measurements. The theoretical relations have been used in the development of a spherically focused tool less affected by eccentering. Tool responses predicted on the basis of the theoretical relations were found to be consistent with the results of test‐tank measurements made for one of the devices studied. Some field experiments have been made with centered and eccentered spherically focused tools, and more are to be done.

scholarly journals Undulating dark matter

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Joe Davighi ◽  
Matthew McCullough ◽  
Joseph Tooby-Smith
Keyword(s):  
Dark Matter ◽  
Dipole Moment ◽  
Time Dependence ◽  
Electric Dipole Moment ◽  
Electron Scattering ◽  
Electric Dipole ◽  
Dark Sector ◽  
Scattering Rate ◽  
Discovery Potential ◽  
Visible Sector

Abstract We suggest that an interplay between microscopic and macroscopic physics can give rise to dark matter (DM) whose interactions with the visible sector fundamentally undulate in time, independent of celestial dynamics. A concrete example is provided by fermionic DM with an electric dipole moment (EDM) sourced by an oscillating axion-like field, resulting in undulations in the scattering rate. The discovery potential of light DM searches can be enhanced by additionally searching for undulating scattering rates, especially in detection regions where background rates are large and difficult to estimate, such as for DM masses in the vicinity of 1 MeV where DM-electron scattering dominantly populates the single electron bin. An undulating signal could also reveal precious dark sector information after discovery. In this regard we emphasise that, if the recent XENON1T excess of events is due to light DM scattering exothermically off electrons, future analyses of the time-dependence of events could offer clues as to the microscopic origins of the putative signal.

scholarly journals The results of using method of the VES-IP at studying sand-gravel mixtures on the territory of Mosalsky district of Kaluga region

2016 ◽  
pp. 52-58
Author(s):  
V. A. Kulikov ◽  
S. A. Anoshina ◽  
A. V. Solovieva
Keyword(s):  
Traditional Method ◽  
Thick Layer ◽  
Induced Polarization ◽  
Clay Particles ◽  
Equivalent Models ◽  
New Methods ◽  
Electrical Sounding ◽  
Kaluga Region ◽  
Sand And Gravel ◽  
Selection Of

Vertical electrical sounding is a traditional method of exploration of sand-gravel mix deposits. At present geophysicists are challenged not only to discover of the as-dug gravel, but also to determine its basic properties, allocate within the deposits plots with high percentage of gravel or determine the content of clay particles in the sands. To meet these challenges it is necessary to use new methods, in particular, the method of induced polarization. The paper presents the results of DC/IP surveys executed in the territory of Mosalsky district of Kaluga region in 2015. The work was carried out as already known, developed fields of sand-gravel mix deposits, as well as new search areas, which have not yet conducted drilling works. As shown by the results all the deposits of sand-gravels are characterized by high values of induced polarization. The complex selection of the curves of apparent resistivity and apparent polarizability substantially narrows the boundaries of equivalent models in the interpretation of data in complex geological situations where sand and gravel deposits slightly different from the surrounding rocks or covered with a thick layer of conductive loam.

The Temporal Dipole Moment Of Solute Molecules Undergoing Charge Transfer

2004 ◽  
Vol 59 (7-8) ◽  
pp. 476-480 ◽  
Author(s):  
V. I. Tomin ◽  
A. Krzysztofowicz
Keyword(s):  
Correlation Function ◽  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Time Dependence ◽  
Electric Dipole ◽  
Polar Solvent ◽  
Dipole Moments ◽  
Experimental Methods ◽  
Geometrical Transformation

Important information about a geometrical transformation of solute molecules undergoing charge transfer in the excited state could be obtained from the knowledge of its dipole moment change in time, while experimental methods allow to obtain only stationary values of dipole moments for both the local excited and the charge transfer states. On the basis of the theory of solvatochromism the relation for a time dependence of dipole moment on the correlation function for instant spectra kinetics has been deduced. Time dependence of the electric dipole moment of dimethylaminobenzonithryle in a polar solvent is presented. The initial and the final values of the dipole moments are close to those obtained by means of stationary spectroscopy methods.

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