Relations between horizontal and vertical gradients of potential fields

Geophysics ◽  
1989 ◽  
Vol 54 (5) ◽  
pp. 662-663 ◽  
Author(s):  
Laust B. Pedersen
Keyword(s):  
Magnetic Fields ◽  
Potential Field ◽  
The Other ◽  
Potential Fields ◽  
Derived Relations ◽  
Alternative Derivation ◽  
Wavenumber Domain ◽  
Vertical Gradients

Nabighian (1984) and Nelson (1986) have both derived relations between horizontal and vertical gradients of magnetic fields (or any other potential field), whereby a knowledge of one enables one to calculate the other. As pointed out by Nelson, Nabighian’s derivation is quite lengthy. In the following, I offer an alternative derivation in the wavenumber domain, which is even shorter than that given by Nelson.

Potential‐field continuation between irregular surfaces—Remarks on the method by Xia et al.

Geophysics ◽  
1998 ◽  
Vol 63 (1) ◽  
pp. 104-108 ◽  
Author(s):  
Bruno Meurers ◽  
Roland Pail
Keyword(s):  
Magnetic Fields ◽  
Potential Field ◽  
Field Data ◽  
Potential Field Data ◽  
Irregular Surfaces ◽  
Equivalent Source ◽  
Wavenumber Domain ◽  
Excellent Method ◽  
Reducing Potential ◽  
Field Continuation

Xia et al. (1993) offer an excellent method for potential‐field continuation between irregular surfaces by applying the equivalent source technique. This method has proven to be the fastest and most stable procedure for solving the problem of reducing potential‐field data to a constant datum (e.g., Pail, 1995) as long as no sources exist between observation surface and the equivalent stratum. The authors suggest using special equations for the continuation of magnetic fields. Theoretically this is correct, but neither necessary nor well suited, because of the characteristics of the operator for magnetic fields applied in the wavenumber domain.

scholarly journals General Environment Description Language

2021 ◽  
Vol 11 (2) ◽  
pp. 740
Author(s):  
Krzysztof Zatwarnicki ◽  
Waldemar Pokuta ◽  
Anna Bryniarska ◽  
Anna Zatwarnicka ◽  
Andrzej Metelski ◽  
...  
Keyword(s):  
Intelligent Systems ◽  
General Purpose ◽  
The Other ◽  
Potential Fields ◽  
General Intelligence ◽  
Language Usage ◽  
Description Language ◽  
It Systems ◽  
New Research ◽  
Future Work

Artificial intelligence has been developed since the beginning of IT systems. Today there are many AI techniques that are successfully applied. Most of the AI field is, however, concerned with the so-called “narrow AI” demonstrating intelligence only in specialized areas. There is a need to work on general AI solutions that would constitute a framework enabling the integration of already developed narrow solutions and contribute to solving general problems. In this work, we present a new language that potentially can become a base for building intelligent systems of general purpose in the future. This language is called the General Environment Description Language (GEDL). We present the motivation for our research based on the other works in the field. Furthermore, there is an overall description of the idea and basic definitions of elements of the language. We also present an example of the GEDL language usage in the JSON notation. The example shows how to store the knowledge and define the problem to be solved, and the solution to the problem itself. In the end, we present potential fields of application and future work. This article is an introduction to new research in the field of Artificial General Intelligence.

The midpoint method: Magnetic interpretation of dikes and faults

Geophysics ◽  
1985 ◽  
Vol 50 (5) ◽  
pp. 834-839 ◽  
Author(s):  
I. V. Radhakrishna Murthy
Keyword(s):  
Characteristic Point ◽  
The Other ◽  
Magnetic Interpretation ◽  
Midpoint Method ◽  
Vertical Gradients

A method of magnetic interpretation of arbitrarily magnetized dikes and faults is developed, based on the properties of a new characteristic point called the “midpoint.” Anomaly profiles at two levels are considered, the maximum and minimum anomalies on them are located, and their midpoints are plotted. The rate of shift of the midpoint with elevation is a measure of the direction of magnetization. The distances between the points of maximum and minimum anomalies and the ratio of horizontal to vertical gradients in the case of faults are used to calculate the other parameters. I also suggest application of the method to anomalies of sheet‐like bodies.

scholarly journals Virtual Electric Dipole Field Applied to Autonomous Formation Flight Control of Unmanned Aerial Vehicles

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4540
Author(s):  
Leszek Ambroziak ◽  
Maciej Ciężkowski
Keyword(s):  
Control System ◽  
Unmanned Aerial Vehicles ◽  
Flight Control ◽  
Electric Dipole ◽  
Potential Field ◽  
Control Algorithm ◽  
Formation Flight ◽  
Potential Fields ◽  
Dipole Potential ◽  
Aerial Vehicles

The following paper presents a method for the use of a virtual electric dipole potential field to control a leader-follower formation of autonomous Unmanned Aerial Vehicles (UAVs). The proposed control algorithm uses a virtual electric dipole potential field to determine the desired heading for a UAV follower. This method’s greatest advantage is the ability to rapidly change the potential field function depending on the position of the independent leader. Another advantage is that it ensures formation flight safety regardless of the positions of the initial leader or follower. Moreover, it is also possible to generate additional potential fields which guarantee obstacle and vehicle collision avoidance. The considered control system can easily be adapted to vehicles with different dynamics without the need to retune heading control channel gains and parameters. The paper closely describes and presents in detail the synthesis of the control algorithm based on vector fields obtained using scalar virtual electric dipole potential fields. The proposed control system was tested and its operation was verified through simulations. Generated potential fields as well as leader-follower flight parameters have been presented and thoroughly discussed within the paper. The obtained research results validate the effectiveness of this formation flight control method as well as prove that the described algorithm improves flight formation organization and helps ensure collision-free conditions.

Resistive transition broadening in two-phase polycrystalline YBaCuO

1993 ◽  
Vol 8 (5) ◽  
pp. 957-961 ◽  
Author(s):  
J.C. Abele ◽  
R.L. Bristol ◽  
T.C. Nguyen ◽  
M.W. Ohmer ◽  
L.S. Wood
Keyword(s):  
Magnetic Fields ◽  
Computer Models ◽  
Structured Data ◽  
The Other ◽  
Critical Ratio ◽  
Resistive Transition ◽  
Two Phase ◽  
Two Phases

A model proposed by Tinkham1to explain the resistance versus temperature broadening found in highTcsuperconductors in applied magnetic fields is extended to “foot and knee”-structured data taken on polycrystalline YBa2Cu3O6+δ. The proposed extension involves a series combination of two types of superconductors. For this series combination to result, a critical ratio of the two types of superconductors must be met—a result common to both percolation and randomized cellular autonoma theory. This critical ratio is investigated via statistical computer models of a polycrystalline superconductor having two phases of crystallites—one with substantially lowerJcthan the other.

scholarly journals Liberalism, Governmentality and Counter-Conduct; An Introduction to Foucauldian Analytics of Liberal Civil Society Notions

2015 ◽  
pp. 8-35 ◽  
Author(s):  
Miikka Pyykkönen
Keyword(s):  
Civil Society ◽  
Collective Action ◽  
Potential Field ◽  
Political Action ◽  
The Other ◽  
Coercive Power ◽  
Historical Reality ◽  
Other Hand ◽  
The One

This article gives an analysis of Foucault’s studies of civil society and the various liberalist critiques of government. It follows from Foucault’s genealogical approach that “civil society” does not in itself possess any form of transcendental existence; its historical reality must be seen as the result of the productive nature of the power-knowledge-matrices. Foucault emphasizes that modern governmentality—and more specifically the procedures he names “the conduct of conduct”—is not exercised through coercive power and domination, but is dependent on the freedom and activeness of individuals and groups of society. Civil society is thus analyzed as fundamentally ambivalent: on the one hand civil society is a field where different kinds of technologies of governance meet the lives and wills of groups and individuals, but on the other hand it is a potential field of what Foucault called ‘counter-conduct’ – for both collective action and individual political action.

Effect of Centrifugal Force Effect on Magneto-Rheological Fluid Clutches

2002 ◽  
Author(s):  
Vijay A. Neelakantan ◽  
Gregory N. Washington
Keyword(s):  
Magnetic Fields ◽  
Design Methodology ◽  
Volume Fraction ◽  
The Other ◽  
Particle Orientation ◽  
Centrifugal Forces ◽  
Mr Fluid ◽  
Set Up ◽  
Magneto Rheological ◽  
Very High

The property of magnetorheological fluids to change their yield stress depending on applied magnetic fields can be employed to develop many controllable devices one of them being MR fluid based clutches. One major problem however with MR fluid based clutches is that at high rotational speeds, the iron/ferrous particles in the MR fluid centrifuge due to very high centrifugal forces. Thus the particles move outward as the speed increases thereby making the fluid non-homogeneous. Many times however the initial analysis assumes fluid homogeneity, which is really not the case. In this paper this problem is addressed by assuming various volume fraction profiles describing the fluid particle orientation. Two cases, one with a linear profile and the other with an exponential profile are discussed. Expressions for the torque transmitted are derived at for both disc shaped and cylindrical shaped clutches. In addition, the use of a MR sponge based clutch that may indeed reduce the effect of centrifugal forces significantly is described. The design methodology and configuration for the sponge clutch are also discussed. An experimental set up used to test the clutch is also described.

Statistics on Jupiter's Current Sheet with Juno Data: Geometry, Magnetic Fields and Energetic Particles

2021 ◽  
Author(s):  
Zhi-Yang Liu ◽  
Qiu-Gang Zong ◽  
Michel Blanc
Keyword(s):  
Magnetic Fields ◽  
Current Sheet ◽  
Power Law ◽  
Heavy Ions ◽  
Particle Interaction ◽  
The Other ◽  
Gaussian Functions ◽  
Fixed Energy ◽  
Thin Current Sheet ◽  
A Current

<p>Jupiter's magnetosphere contains a current sheet of huge size near its equator. The current sheet not only mediates the global mass and energy cycles of Jupiter's magnetosphere, but also provides an occurring place for many localized dynamic processes, such as reconnection and wave-particle interaction. To correctly evaluate its role in these processes, a statistical description of the current sheet is required. To this end, here we conduct statistics on Jupiter's current sheet, with four-year Juno data recorded in the 20-100 Jupiter radii, post-midnight magnetosphere. The results suggest a thin current sheet whose thickness is comparable with the gyro-radius of dominant ions. Magnetic fields in the current sheet decrease in power-law with increasing radial distances. At fixed energy, the flux of electrons and protons increases with decreasing radial distances. On the other hand, at fixed radial distances, the flux decreases in power-law with increasing energy. The flux also varies with the distances to the current sheet center. The corresponding relationship can be well described by Gaussian functions peaking at the current sheet center. In addition, the statistics show the flux of oxygen- and sulfur-group ions is comparable with the flux of protons at the same energy and radial distances, indicating the non-negligible effects of heavy ions on current sheet dynamics. From these results, a statistical model of Jupiter's current sheet is constructed, which provides us with a start point of understanding the dynamics of the whole Jupiter's magnetosphere.</p>

scholarly journals Vertical Velocities Associated With Plage Region Magnetic Fields

1971 ◽  
Vol 43 ◽  
pp. 293-297 ◽  
Author(s):  
R. G. Giovanelli ◽  
J. V. Ramsay
Keyword(s):  
Magnetic Fields ◽  
The Other ◽  
Line Centre ◽  
Filter Bandwidth ◽  
Blue Wing ◽  
Wide Range ◽  
Plage Region

The Culgoora magnetograph (Ramsay et al., 1970) produces simultaneous filtergrams in opposite circular polarizations at a wavelength selected by a filter bandwidth 0.005 nm (Ramsay et al., 1970). In the blue wing of the 610.27 nm line of CaI, regions of magnetic fields in strong or weak plages are very obvious in one or other polarization, depending on polarity, even before subtraction; in one polarization they are bright, but almost invisible in the other. They are more difficult to discern at equal intervals from the line centre in the other wing (Figure 1). When subtractions are carried out to yield magnetograms of the same sense, the two magnetograms from opposite wings give results which appear to be much the same. An example is shown in Figure 2. Similar results are obtained over a wide range of positions in the wings of the 610.27 nm line.

scholarly journals A study of the localization of flares in selected active regions

1968 ◽  
Vol 35 ◽  
pp. 318-325 ◽  
Author(s):  
M. J. Martres ◽  
R. Michard ◽  
I. Soru-Iscovici ◽  
T. Tsap
Keyword(s):  
Magnetic Fields ◽  
Magnetic Structure ◽  
Active Regions ◽  
The Other ◽  
Cooperative Study ◽  
Solar Active Regions

From the material gathered during the ‘Cooperative Study of Solar Active Regions’, we studied the flare locations in AR magnetic structure, and flare relations to changes in the magnetic fields and spot configurations. Besides a confirmation of previous results, we find that flares are often associated with two features of the spot configuration evolving in opposite senses, one growing, the other declining.

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