THREE‐LAYER RESISTIVITY CURVES FOR THE ELTRAN ELECTRODE CONFIGURATION

Geophysics ◽  
1940 ◽  
Vol 5 (1) ◽  
pp. 43-46 ◽  
Author(s):  
S. S. West
Keyword(s):  
Apparent Resistivity ◽  
Electrode Configuration ◽  
Published Data ◽  
Electrode Separation ◽  
Configuration Data

A method is described by which standard curves of apparent resistivity vs. electrode separation can be calculated for certain electrode configurations from the published data for the Wenner configuration. Data are given for plotting curves representing 15 sets of values of the three layer parameters in the case of the Eltran configuration.

POTENTIAL AND APPARENT RESISTIVITY OVER DIPPING BEDS

Geophysics ◽  
1956 ◽  
Vol 21 (3) ◽  
pp. 780-793 ◽  
Author(s):  
Jerome Chastenet De Gery ◽  
Geza Kunetz
Keyword(s):  
Point Source ◽  
Current Density ◽  
Potential Field ◽  
Apparent Resistivity ◽  
Exact Expression ◽  
Electrode Configuration ◽  
Vertical Profiles ◽  
The Earth ◽  
Electrode Separation

The potential field due to a point source of current, located on the surface of the earth near a dipping bed, is given in an exact expression and modified expressions are developed for computations. These expressions lead to graphs of the potential field and to apparent resistivity vertical profiles which are presented. The Schlumberger electrode configuration is used. This configuration consists of two current electrodes and two potential electrodes, the latter placed close enough together that the current density between them can be considered to be uniform. With this configuration oriented perpendicular to the strike of the dipping bed, the apparent resistivity is paradoxical in that it approaches either zero or infinity as the electrode separation increases without limit.

A TRI‐POTENTIAL METHOD OF RESISTIVITY PROSPECTING

Geophysics ◽  
1956 ◽  
Vol 21 (2) ◽  
pp. 455-469 ◽  
Author(s):  
E. W. Carpenter ◽  
G. M. Habberjam
Keyword(s):  
Apparent Resistivity ◽  
Potential Method ◽  
Electrode Configuration ◽  
Practical Application ◽  
Resistivity Method

This paper describes a method whereby three resistances are measured for a four electrode configuration, and relations between these three resistances and their corresponding apparent resistivities are derived. The practical application of the resistance relation as a means of detecting observational and instrumental errors is indicated. The concept of apparent resistivity is examined and by means of examples it is shown that the apparent resistivity can take negative values. Finally, the possibility of using the triple resistivity method as a means of distinguishing between the effects of lateral and vertical resistivity changes on depth probes is discussed.

THEORETICAL HORIZONTAL RESISTIVITY PROFILES OVER HEMISPHERICAL SINKS

Geophysics ◽  
1961 ◽  
Vol 26 (3) ◽  
pp. 342-354 ◽  
Author(s):  
Kenneth L. Cook ◽  
Russel L. Gray
Keyword(s):  
Digital Computer ◽  
Apparent Resistivity ◽  
Reflection Factor ◽  
General Utility ◽  
Qualitative Interpretation ◽  
Electrode Separation

An album of 40 sets (about 200 different curves) of theoretical horizontal resistivity profiles over and near outcropping hemispherical sinks shows the effects of sink diameter, reflection factor k, and distance of the traverse from the center of the sink upon the magnitude and shape of the apparent resistivity curves. Curves for sink diameters of 16a, 8a, 6a, 4a, 2a, a, and 0.5a, and reflection factors k of ±0.8, ±0.6, ±0.4, and ±0.2 are included. The values of apparent resistivity for both the Lee and Wenner configurations were computed using a digital computer. In general, the larger the sink, the larger the magnitude of the apparent resistivity anomaly up to a sink diameter of about 8a, for which the apparent resistivity over the central part of the sink is essentially equal to the resistivity of the sink, irrespective of the reflection factor. For sink diameters equal to the electrode separation a, large apparent resistivity anomalies result from “pseudo‐focusing” effects. The major peaks of the apparent resistivity curves, which lie outside the edges of the sink for negative reflection factors and inside for positive reflection factors, can be used to detect the edges of the sinks. The album of curves provides a general utility for the qualitative interpretation of apparent resistivity anomalies over features other than hemispherical sinks, such as faults (for large sinks), dikes, grabens, and similar features.

MAPPING GILSONITE VEINS WITH THE ELECTRICAL RESISTIVITY METHOD

Geophysics ◽  
1967 ◽  
Vol 32 (2) ◽  
pp. 302-310 ◽  
Author(s):  
Walter W. Hays ◽  
Otto W. Nuttli ◽  
Leroy Scharon
Keyword(s):  
Electrical Resistivity ◽  
Theoretical Model ◽  
Apparent Resistivity ◽  
Electrical Current ◽  
Electrode Configuration ◽  
Electrode Spacing ◽  
Uinta Basin ◽  
Resistivity Method ◽  
Electrical Resistivity Method

Gish‐Rooney type electrical resistivity equipment was employed to map the location and structural attitude of gilsonite veins in the Uinta Basin, southeast of Vernal, Utah. Horizontal profiles at right angles to the strike of the dike‐like gilsonite veins were made using the Wenner electrode configuration. Very sharp anomalies with a peak apparent resistivity value of the order of 20,000–25,000 ohm‐cm were observed. The peak values were measured over the center of the vein, but smaller auxiliary highs were also observed, symmetrically spaced on each side of the vein. The position of the auxiliary high varied as a function of the electrode spacing and was found to occur when the current stake was located in the gilsonite. The observed field profiles were compared with various theoretical profiles computed from theoretical apparent resistivity expressions derived through the use of images. The best correlation was obtained when the theoretical model was assumed to have an infinite resistivity relative to that of the surrounding material. This correlation supports the conclusion that the gilsonite veins, because of their extremely large resistivity and their vertical attitude, act as a vertical insulating sheet to the flow of electrical current in the ground.

A SET OF CURVES TO ASSIST IN THE INTERPRETATION OF THE THREE LAYER RESISTIVITY PROBLEM

Geophysics ◽  
1937 ◽  
Vol 2 (4) ◽  
pp. 329-341 ◽  
Author(s):  
W. W. Wetzel ◽  
Howard V. McMurry
Keyword(s):  
Layer Thickness ◽  
Field Data ◽  
Apparent Resistivity ◽  
Electrode Configuration ◽  
Wide Range

A set of apparent resistivity curves for the Wenner electrode configuration is given. This set covers a wide range of variations of layer thickness and resistivity for the three‐layer earth. A method for interpretation of field data is outlined.

A RESISTOLOG SURVEY OF THE LOMA ALTO‐SEVEN SISTERS AREA OF McMULLEN AND DUVAL COUNTIES, TEXAS

Geophysics ◽  
1946 ◽  
Vol 11 (4) ◽  
pp. 491-504
Author(s):  
Thomas S. West ◽  
Clarence C. Beacham
Keyword(s):  
Cross Section ◽  
Field Data ◽  
Apparent Resistivity ◽  
Oil And Gas ◽  
Direct Detection ◽  
Gas Saturation ◽  
Subsurface Geology ◽  
Electrode Separation

Additional Resistolog field data are shown. This survey is in the Loma Alto‐Seven Sisters area of McMullen and Duval Counties, Texas. The subsurface geology of this area is also shown along with an electric log cross section to which Resistologs have been added. Four of the apparent resistivity curves employed for calculating Resistologs are included for demonstrating the relatively great extent to which apparent resistivity may be influenced by shallow inhomogeneities along a traverse of electrodes which are moved for securing a variation in electrode separation. Several cases of direct detection of oil and gas saturation and successful structural correlations are presented.

scholarly journals Wenner Soundings for Apparent Resistivity Measurements at Small Depths Using a Set of Unequal Bare Electrodes: Selected Case Studies

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 695 ◽  
Author(s):  
Eduardo Faleiro ◽  
Gabriel Asensio ◽  
Gregorio Denche ◽  
Daniel Garcia ◽  
Jorge Moreno
Keyword(s):  
Case Studies ◽  
Apparent Resistivity ◽  
Resistivity Measurements ◽  
Electrode Separation

The possibility of using a set of unequal electrodes, within limits, in a Wenner arrangement for the measurement of apparent resistivity at small depths is explored in this paper. A procedure in which only a simple preliminary calibration is necessary to obtain the best measurements of the apparent resistivity is proposed. On the basis of some case studies, a comparison with the usual procedures to obtain the apparent resistivity from resistance measurements is carried out. The results showed that when an unequal set of electrodes was used, the procedure proposed here was the only one that guaranteed the best apparent resistivity values for any value of electrode separation in the Wenner arrangement, especially for those associated with small depths.

Influence of nascent polypeptide positive charges on translation dynamics

2020 ◽  
Vol 477 (15) ◽  
pp. 2921-2934
Author(s):  
Rodrigo D. Requião ◽  
Géssica C. Barros ◽  
Tatiana Domitrovic ◽  
Fernando L. Palhano
Keyword(s):  
Mrna Decay ◽  
Translation Termination ◽  
Published Data ◽  
Translation Efficiency ◽  
Amino Acid Residues ◽  
High Concentration ◽  
Strong Argument ◽  
Translation Arrest ◽  
Exit Tunnel ◽  
Positively Charged

Protein segments with a high concentration of positively charged amino acid residues are often used in reporter constructs designed to activate ribosomal mRNA/protein decay pathways, such as those involving nonstop mRNA decay (NSD), no-go mRNA decay (NGD) and the ribosome quality control (RQC) complex. It has been proposed that the electrostatic interaction of the positively charged nascent peptide with the negatively charged ribosomal exit tunnel leads to translation arrest. When stalled long enough, the translation process is terminated with the degradation of the transcript and an incomplete protein. Although early experiments made a strong argument for this mechanism, other features associated with positively charged reporters, such as codon bias and mRNA and protein structure, have emerged as potent inducers of ribosome stalling. We carefully reviewed the published data on the protein and mRNA expression of artificial constructs with diverse compositions as assessed in different organisms. We concluded that, although polybasic sequences generally lead to lower translation efficiency, it appears that an aggravating factor, such as a nonoptimal codon composition, is necessary to cause translation termination events.

Metallic prions

2004 ◽  
Vol 71 ◽  
pp. 193-202 ◽  
Author(s):  
David R Brown
Keyword(s):  
Prion Protein ◽  
Binding Capacity ◽  
Normal Function ◽  
Transmissible Spongiform Encephalopathies ◽  
Published Data ◽  
Normal Brain ◽  
Copper Binding ◽  
Loss Of Function ◽  
Spongiform Encephalopathies ◽  
The Brain

Prion diseases, also referred to as transmissible spongiform encephalopathies, are characterized by the deposition of an abnormal isoform of the prion protein in the brain. However, this aggregated, fibrillar, amyloid protein, termed PrPSc, is an altered conformer of a normal brain glycoprotein, PrPc. Understanding the nature of the normal cellular isoform of the prion protein is considered essential to understanding the conversion process that generates PrPSc. To this end much work has focused on elucidation of the normal function and activity of PrPc. Substantial evidence supports the notion that PrPc is a copper-binding protein. In conversion to the abnormal isoform, this Cu-binding activity is lost. Instead, there are some suggestions that the protein might bind other metals such as Mn or Zn. PrPc functions currently under investigation include the possibility that the protein is involved in signal transduction, cell adhesion, Cu transport and resistance to oxidative stress. Of these possibilities, only a role in Cu transport and its action as an antioxidant take into consideration PrPc's Cu-binding capacity. There are also more published data supporting these two functions. There is strong evidence that during the course of prion disease, there is a loss of function of the prion protein. This manifests as a change in metal balance in the brain and other organs and substantial oxidative damage throughout the brain. Thus prions and metals have become tightly linked in the quest to understand the nature of transmissible spongiform encephalopathies.

Accuracy of Four Language Analysis Procedures Performed Automatically

2001 ◽  
Vol 10 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Steven H. Long ◽  
Ron W. Channell
Keyword(s):  
Automatic Identification ◽  
Published Data ◽  
Typically Developing ◽  
Language Impaired ◽  
Productivity Data ◽  
Language Analysis ◽  
Word Classes ◽  
Human Coder ◽  
Impaired Children ◽  
Metalinguistic Skills

Most software for language analysis has relied on an interaction between the metalinguistic skills of a human coder and the calculating ability of the machine to produce reliable results. However, probabilistic parsing algorithms are now capable of highly accurate and completely automatic identification of grammatical word classes. The program Computerized Profiling combines a probabilistic parser with modules customized to produce four clinical grammatical analyses: MLU, LARSP, IPSyn, and DSS. The accuracy of these analyses was assessed on 69 language samples from typically developing, speech-impaired, and language-impaired children, 2 years 6 months to 7 years 10 months. Values obtained with human coding and by the software alone were compared. Results for all four analyses produced automatically were comparable to published data on the manual interrater reliability of these procedures. Clinical decisions based on cutoff scores and productivity data were little affected by the use of automatic rather than human-generated analyses. These findings bode well for future clinical and research use of automatic language analysis software.

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