ANALYTIC MODELS FOR THE INTERPRETATION OF ELECTRICAL SURVEYS USING BURIED CURRENT ELECTRODES

Geophysics ◽  
1973 ◽  
Vol 38 (3) ◽  
pp. 513-529 ◽  
Author(s):  
Donald D. Snyder ◽  
Richard M. Merkel
Keyword(s):  
Apparent Resistivity ◽  
Three Dimensional ◽  
Drill Hole ◽  
Surface Electrode ◽  
Sphere Model ◽  
Current Electrode ◽  
Anomaly Pattern ◽  
Lateral Offset ◽  
Analytic Models ◽  
A Current

The IP response and the apparent resistivity resulting from a buried current pole in the presence of a stratigraphic target and a three‐dimensional target have been studied. The targets were modeled using a layered model to simulate the stratigraphic target and a buried sphere model to simulate the three‐dimensional target. The results show that there is a substantial increase in the response of the target measured at the surface for current electrode depths of greater than half the depth to the top of the target. A larger anomalous response is of particular importance when dealing with deeply buried targets from which little or no response is measured using conventional surface electrode methods. Furthermore, the results indicate that a survey around a drill hole containing a current electrode can be used to outline mineralization in the immediate vicinity of the drill hole. Some empirical observations resulting from our study are presented which relate the lateral offset of the target from the drill hole and its depth to characteristics of the anomaly pattern as measured on the surface.

THREE‐DIMENSIONAL RESISTIVITY AND INDUCED‐POLARIZATION MODELING USING BURIED ELECTRODES

Geophysics ◽  
1977 ◽  
Vol 42 (5) ◽  
pp. 1006-1019 ◽  
Author(s):  
Jeffrey J. Daniels
Keyword(s):  
Electrical Properties ◽  
Apparent Resistivity ◽  
Three Dimensional ◽  
Equipotential Surface ◽  
Induced Polarization ◽  
The Body ◽  
Surface Electrode ◽  
Surface Integral ◽  
Drill Holes ◽  
Resistivity Modeling

The three‐dimensional induced‐polarization and resistivity‐modeling problem for buried source and receiver electrodes is solved by using a modified form of Barnett’s surface‐integral technique originally developed for surface‐electrode configurations. Six different buried electrode configurations are considered in this study: three types of hole‐to‐hole configurations, hole‐to‐surface and surface‐to‐hole configurations, and the single hole (bipole‐bipole) configuration. Results show there is no “best” method for all situations encountered in the field. The choice of method depends upon depth of the body, spacing of drill holes, and electrical properties of the body. In hole‐to‐hole measurements, the geometric factor (necessary for the computation of the apparent resistivity) becomes infinitely large or infinitely small whenever the receiving bipole is placed at a depth so that it lies on a zero equipotential surface. This leads to the formation of apparent resistivity anomalies that are extremely sensitive to the presence of the body but that are also complicated and not easily correlated with the position of the body. It is shown that diagnostic and easily interpretable anomalies are obtained by selecting the proper source‐receiver configurations.

A mise‐à‐la‐masse study of the Cavendish Geophysical Test Site

Geophysics ◽  
1983 ◽  
Vol 48 (9) ◽  
pp. 1252-1257 ◽  
Author(s):  
L. Mansinha ◽  
C. J. Mwenifumbo
Keyword(s):  
Potential Field ◽  
Test Site ◽  
Drill Hole ◽  
Mineral Deposit ◽  
Current Electrode ◽  
Underground Openings ◽  
Mineralized Zone ◽  
Electrical Prospecting ◽  
Drill Holes ◽  
A Current

The mise‐à‐la‐masse method of electrical prospecting is used when a conductive, mineralized zone has already been located. A current electrode is placed directly in the mineralized zone, and the resulting potential field is mapped on the surface or in the subsurface via drill holes or underground openings. The potential field reflects the shape, size, and orientation of the mineral deposit. A field study of this method was carried out at the Cavendish Geophysical Test Site in Ontario, Canada. Two vein‐type mineralized bodies, zone A and zone B, are known to exist at the site. Drill holes were used to implant a current electrode in each of the veins and surface potentials were measured. The extension of the two zones in the strike direction was established with the resulting mise‐à‐la‐masse potential profiles. However, no electrical continuity between zones A and B could be discerned, indicating that the veins are not connected at depth. The dip of zone A appears to be toward the west, contrary to that inferred from the drill hole logs. The measured potentials are influenced by the mutual proximity of the far current and potential electrodes as well as by the location of the electrodes with reference to the local geologic structure.

On sensitivity of surface‐to‐borehole resistivity measurements to the attitude and the depth to center of a three‐dimensional spheroid

Geophysics ◽  
1985 ◽  
Vol 50 (7) ◽  
pp. 1173-1178 ◽  
Author(s):  
F. W. Yang ◽  
S. H. Ward
Keyword(s):  
Apparent Resistivity ◽  
Current Source ◽  
Three Dimensional ◽  
The Body ◽  
Simple Method ◽  
Pilot Studies ◽  
Resistivity Measurements ◽  
Oblate Body ◽  
A Current

Borehole‐to‐surface and surface‐to‐borehole resistivity measurements are versatile but not totally tested methods for detecting anomalies in the vicinity of a borehole. The former method has been discussed by several authors (Alfano, 1962; Merkel, 1971; Merkel and Alexander, 1971; Barnett, 1972; Snyder and Merkel, 1973; Snyder, 1976; Daniels, 1977, 1978, and 1983), but the latter has not received much attention. Morrison (1971) and Daniels (1977) are among the few who have addressed the problem. Each method has its own advantages. Surface‐to‐borehole resistivity measurements are made by placing a current source on the surface and measuring the apparent resistivity in a borehole in which the measuring electrodes are closer to the body than in the borehole‐to‐surface case. Pilot studies presented here suggest that the surface‐to‐borehole method can provide indicators of the attitude and the depth to the center of a body. This paper illustrates a simple method for qualitatively determining the attitude and the depth to the center of a body for a thin three‐dimensional (3-D) conductive oblate body with the surface‐to‐borehole technique. Attitude conveys the orientation of the body— horizontal, vertical dipping toward a borehole, or dipping away from a borehole.

scholarly journals Torso geometry reconstruction and body surface electrode localization using three-dimensional photography

2018 ◽  
Vol 51 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Erick A. Perez-Alday ◽  
Jason A. Thomas ◽  
Muammar Kabir ◽  
Golriz Sedaghat ◽  
Nichole Rogovoy ◽  
...  
Keyword(s):  
Body Surface ◽  
Three Dimensional ◽  
Surface Electrode ◽  
Geometry Reconstruction ◽  
Electrode Localization

scholarly journals Fluoride removal using electrocoagulation technique

2021 ◽  
Vol 877 (1) ◽  
pp. 012047
Author(s):  
Hind M. Ewadh ◽  
Mustafa J. Al Imari ◽  
Sabrean F. Jawad ◽  
Hayfaa A. Mubarak
Keyword(s):  
Severe Disease ◽  
Electrical Current ◽  
Electrode Spacing ◽  
Polluted Water ◽  
Fluoride Removal ◽  
Acidic Environment ◽  
Current Electrode ◽  
The Past ◽  
The Impact ◽  
A Current

Abstract A modest quantity of fluoride can increase the mineralization of teeth and reduce their cavities. But the presomerence of fluoride in excess in water can lead to severe disease infertility. In the past few decades, scientists have thus been preoccupied with developing ways to reduce sewage fluoride concentrations and reduce their effects on human health. The present study is aimed at using the technology of electrocoagulation to remove fluoride from polluted water. Tests have been done to examine the elimination of fluoride with a rectangular electrocoagulation cell and examine the impact of the experimental aspects on fluoride extraction, specifically electrical current, electrode spacing, and pH. The authors found that 93% of the fluoride has been extracted using 5mm spaced electrodes with a current density of 2 mA/cm2 and a level of pH of 7 from the polluted water after 20 min of processing. Experimental factors considerably impact the efficacy of fluoride removal. In the acidic environment, greater effectiveness of fluoride removal is being attained. The elimination effectiveness depends directly on the electric current, whereas the distance between poles is adversely linked to fluoride elimination.

A current assessment of photosystem II structure

1996 ◽  
Vol 16 (2) ◽  
pp. 159-187 ◽  
Author(s):  
William V. Nicholson ◽  
Robert C. Ford ◽  
Andreas Holzenburg
Keyword(s):  
Photosystem Ii ◽  
Structural Information ◽  
Three Dimensional ◽  
Structural Data ◽  
X Ray Diffraction ◽  
Membrane Protein Complex ◽  
Fast Absorption ◽  
Current Assessment ◽  
Electron Microscopical ◽  
A Current

This review covers the recent progress in the elucidation of the structure of photosystem II (PSII). Because much of the structural information for this membrane protein complex has been revealed by electron microscopy (EM), the review will also consider the specific technical and interpretation problems that arise with EM where they are of particular relevance to the structural data. Most recent reviews of photosystem II structure have concentrated on molecular studies of the PSII genes and on the likely roles of the subunits that they encode or they were mainly concerned with the biophysical data and fast absorption spectroscopy largely relating to electron transfer in various purified PSII preparations. In this review, we will focus on the approaches to the three-dimensional architecture of the complex and the lipid bilayer in which it is located (the thylakoid membrane) with special emphasis placed upon electron microscopical studies of PSII-containing thylakoid membranes. There are a few reports of 3D crystals of PSII and of associated X-ray diffraction measurements and although little structural information has so far been obtained from such studies (because of the lack of 3D crystals of sufficient quality), the prospects for such studies are also assessed.

Three-Dimensional Compensation for Minimizing Heating of the Ion in Surface-Electrode Trap

2020 ◽  
Vol 37 (5) ◽  
pp. 053701 ◽  
Author(s):  
Ji Li ◽  
Liang Chen ◽  
Yi-He Chen ◽  
Zhi-Chao Liu ◽  
Hang Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Surface Electrode

The application of the mise-a-la-masse electrical technique in Greenstone belt gold exploration

1989 ◽  
Vol 20 (2) ◽  
pp. 113
Author(s):  
L.G.B.T. Polomé
Keyword(s):  
Greenstone Belt ◽  
Electrical Potential ◽  
Gold Deposits ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Current Electrode ◽  
Barberton Greenstone Belt ◽  
A Current ◽  
Ore Zones ◽  
Gold Bearing

Most of the gold deposits in the Barberton Greenstone belt of South Africa are relatively small and in structurally complex geological areas.The mise-a-la-masse electrical technique, where a current electrode is earthed in a mineralised zone, was used on one of our exploration projects consisting of a sulphides/gold-bearing carbonaceous banded iron formation within a succession of mafic, ultramafic and sedimentary rocks. The technique was successful in delineating individual mineralised units within a broad lithological sequence. During the survey, electrical potential measurements were recorded on surface, in underground drives and in twenty five boreholes. Measurements were also repeated by earthing the mineralised zone in a number of boreholes. Major discontinuities were recognised within the ore zones and used to interpret geological structures. These were then used to define specific units for ore reserve calculations and the application of selected mining techniques.

scholarly journals Topology of Chromosomes 18 and X in Human Blastomeres from 3- to 4-Day-old Embryos

2005 ◽  
Vol 53 (3) ◽  
pp. 273-276 ◽  
Author(s):  
Jan Diblík ◽  
Milan Macek ◽  
Maria-Cristina Magli ◽  
Roman Krejčí ◽  
Luca Gianaroli
Keyword(s):  
Three Dimensional ◽  
Dimensional Sphere ◽  
Chromosome X ◽  
Sphere Model ◽  
Chromosome 18 ◽  
Vitro Fertilization ◽  
Signal Distribution ◽  
Human In Vitro Fertilization

The positions of chromosomes 18 and X fluorescence in situ hybridization signals were analyzed in blastomeres generated from human in vitro fertilization 3- to 4-day-old embryos after preimplantation screening of aneuploidy of chromosomes 13, 16, 18, 21, 22, X, and Y. Fluorescent signal localization compared with a three-dimensional sphere model of random signal distribution revealed significant differences, providing evidence of peripheral localization of chromosome 18 in aneuploid ( p=0.0013) and aneuploid/euploid blastomeres ( p=0.0011). No differences were found in localization of chromosome 18 in euploid and in chromosome X in euploid and aneuploid blastomeres.

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