BASIC THEORY OF INDUCTION LOGGING AND APPLICATION TO STUDY OF TWO‐COIL SONDES

Geophysics ◽  
1962 ◽  
Vol 27 (6) ◽  
pp. 829-858 ◽  
Author(s):  
J. H. Moran ◽  
K. S. Kunz
Keyword(s):  
Current Density ◽  
Building Block ◽  
Skin Effect ◽  
Geometrical Factor ◽  
Rapid Evaluation ◽  
Basic Building Block ◽  
Nonhomogeneous Media ◽  
Induction Logging ◽  
Complete Study ◽  
Negligible Contribution

The basic idea of induction logging is reviewed and the use of the geometrical factor is explained. The rigorous theory based on Maxwell’s equations, is then formulated for the simple two‐coil sonde, which is the basic building block for multicoil sondes. For a homogeneous conducting medium this theory leads to simple solutions for the fields and current density. These simple solutions are exploited in detail to build up a firm understanding of the skin effect phenomenon. The theory is then applied to nonhomogeneous media and numerical results obtained through the use of the IBM 704 are presented. On the basis of this complete study some simple approximate results are presented which allow a rapid evaluation of skin effect in induction logging. The nonhomogeneous media considered in detail are two semi‐infinite beds, thin beds bounded by adjacent formations, and an infinite bed with a borehole or invasion. It is shown that the borehole gives a negligible contribution to the skin effect.

scholarly journals The Future of the Basic Building Block of Telecommunications Network

2020 ◽  
Author(s):  
Ibraheem Kateeb ◽  
Larry Burton ◽  
Naser El-Bathy ◽  
Michael Peluso
Keyword(s):  
Building Block ◽  
Basic Building Block ◽  
The Future ◽  
Telecommunications Network

Implementation of types of VCO

2021 ◽  
Vol 9 (8) ◽  
pp. 2972-2678
Author(s):  
Akshata O. Kattimani
Keyword(s):  
Frequency Shift ◽  
Building Block ◽  
Relaxation Oscillator ◽  
Phase Locked Loop ◽  
Frequency Synthesizers ◽  
Ring Oscillator ◽  
Electronic Systems ◽  
Basic Building Block ◽  
Colpitts Oscillator ◽  
Shift Keying

Abstract: A Voltage Controlled Divider (VCO) is a basic building block in most of the electronic systems. Phase-locked loop (PLL), tone synthesizers, Frequency Shift Keying (FSK), frequency synthesizers, etc make use of VCO’s to generate an oscillating frequency that can be decided with the help of components. Voltage Controlled Divider can be implemented for analog applications. The project proposes three types of VCO using Electric tool and LT Spice XVII tool. The three VCO’s that are implemented are CMOS Ring Oscillator, Colpitts Oscillator and Relaxation Oscillator. These circuits generate two oscillating frequencies that is decided by the circult components. Keywords: Voltage Controlled Divider (VCO), CMOS Ring Oscillator, Colpitts Oscillator, Relaxation Oscillator, oscillating frequency.

Measurement: The Basic Building Block of Research

2020 ◽  
pp. 13-37
Author(s):  
David Weisburd ◽  
Chester Britt ◽  
David B. Wilson ◽  
Alese Wooditch
Keyword(s):  
Building Block ◽  
Basic Building Block

Optical Communication with Invisible Photons

2020 ◽  
pp. 217-226
Author(s):  
M. Suhail Zubairy
Keyword(s):  
Optical Communication ◽  
Building Block ◽  
Communication Protocol ◽  
Zehnder Interferometer ◽  
Transmission Channel ◽  
Basic Building Block ◽  
Obvious Feature ◽  
Interaction Free Measurement ◽  
Mach Zehnder Interferometer

It has always been a self-evident and obvious feature of any kind of communication that there should be an exchange of objects like photons or electrons between the sender and the receiver to convey any information. In this chapter a protocol is presented in which information is transmitted between a sender and receiver with no particles in the transmission channel. The basic building block of this counterfactual communication protocol, the Mach–Zehnder interferometer, is discussed. The concept of interaction-free measurement is also introduced.

Sparse Associative Memory

2019 ◽  
Vol 31 (5) ◽  
pp. 998-1014 ◽  
Author(s):  
Heiko Hoffmann
Keyword(s):  
Associative Memory ◽  
Building Block ◽  
Basic Building Block ◽  
Small Probability ◽  
Hopfield Networks ◽  
New Model ◽  
Brain Functions ◽  
Memory Efficiency ◽  
Low Efficiency

It is still unknown how associative biological memories operate. Hopfield networks are popular models of associative memory, but they suffer from spurious memories and low efficiency. Here, we present a new model of an associative memory that overcomes these deficiencies. We call this model sparse associative memory (SAM) because it is based on sparse projections from neural patterns to pattern-specific neurons. These sparse projections have been shown to be sufficient to uniquely encode a neural pattern. Based on this principle, we investigate theoretically and in simulation our SAM model, which turns out to have high memory efficiency and a vanishingly small probability of spurious memories. This model may serve as a basic building block of brain functions involving associative memory.

Enhanced method for pulse skin effect calculation of cylindrical conductors

2020 ◽  
Vol 39 (3) ◽  
pp. 623-635
Author(s):  
Nebojsa B. Raicevic ◽  
Slavoljub R. Aleksic ◽  
Ilona Iatcheva ◽  
Marinko Barukcic
Keyword(s):  
Electromagnetic Field ◽  
Density Distribution ◽  
Cross Section ◽  
Current Density ◽  
Skin Effect ◽  
Current Density Distribution ◽  
Accurate Solution ◽  
Lightning Strike ◽  
Content Type ◽  
Cylindrical Conductors

Purpose This paper aims to present a new approach to the numerical solution of skin effect integral equations in cylindrical conductors. An approximate, but very simple and accurate method for calculating the current density distribution, skin-effect resistance and inductance, in pulse regime of cylindrical conductor, having a circular or rectangular cross-section, is considered. The differential evolution method is applied for minimization of error functional. Because of its application in the practice, the lightning impulse is observed. Direct and inverse fast Fourier transform is applied. Design/methodology/approach This method contributes to increasing of correctness and much faster convergence. As the electromagnetic field components depend on the current density derivation, the proposed method gives a very accurate solution not only for current density distribution and resistance but also for field components and for internal inductance coefficients. Distribution of current and electromagnetic field in bus-bars can be successfully determined if the proximity effect is included together with the skin effect in calculations. Findings The study shows the strong influence of direct lightning strikes on the distribution of electrical current in cables used in lightning protection systems. The current impulse causes an increase in the current density at all points of the cross-section of the conductor, and in particular the skin effect on the external periphery. Based on the data calculated by using the proposed method, it is possible to calculate the minimum dimensions of the conductors to prevent system failures. Research limitations/implications There are a number of approximations of lightning strike impulse in the literature. This is a limiting factor that affects the reliability and agreement between measured data with calculated values. Originality/value In contrast with other methods, the current density function is approximated by finite functional series, which automatically satisfy wave equation and existing boundary conditions. It is necessary to minimize the functional. This approach leads to a very accurate solution, even in the case when only two terms in current approximation are adopted.

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