Magnetic anomalies of two‐dimensional bodies in a magnetic half‐space

Geophysics ◽  
1982 ◽  
Vol 47 (8) ◽  
pp. 1229-1234 ◽  
Author(s):  
Edson E. S. Sampaio
Keyword(s):  
Fourier Series ◽  
Country Rock ◽  
Magnetic Anomalies ◽  
The Body ◽  
The Self ◽  
Two Dimensional ◽  
Body Dimensions ◽  
Bipolar Coordinates ◽  
Susceptibility Contrast ◽  
Fourier Series Analysis

The presence of magnetization in country rock modifies the anomaly caused by magnetic bodies. Such a modification is distinct from the self‐demagnetization effect of the body, and the concept of susceptibility contrast is not adequate to explain it. We can achieve an exact understanding of the problem by solving the potential function in three media: air, magnetic country rock, and magnetized body. This paper sets up the solution of this problem when the magnetized body is a circular cylinder with an infinitely long horizontal axis, for both a horizontal and a vertical inducing ambient field. It expresses the solution of Laplace’s equation in bipolar coordinates for the potentials in the form of Fourier series. Analysis of the vertical, horizontal, and total magnetic anomalies shows that neglect of country rock magnetization reduces the apparent causative body dimensions.

A comparative study of the relation figures of magnetic anomalies due to two‐dimensional dike and vertical step models

Geophysics ◽  
1982 ◽  
Vol 47 (6) ◽  
pp. 926-931 ◽  
Author(s):  
H. V. Ram Babu ◽  
A. S. Subrahmanyam ◽  
D. Atchuta Rao
Keyword(s):  
Comparative Study ◽  
Major Axis ◽  
Magnetic Anomalies ◽  
The Body ◽  
Two Dimensional ◽  
Depth Ratio ◽  
Characteristic Points ◽  
Vertical Step ◽  
Bottom To Top ◽  
Body Parameters

Magnetic anomalies in vertical and horizontal components, when plotted one against the other in polar form, result in a curve called the relation figure (Werner, 1953). In this paper, a comparative study of the relation figures of magnetic anomalies due to two‐dimensional (2-D) dike and vertical step models is made. The relation figures for these two models are found to be ellipses with different properties. The tangent at the origin to the ellipse is parallel to the major axis of the ellipse for the dike model, whereas it is perpendicular to the major axis for the vertical step. This property may be used to distinguish whether the source is a dike or a vertical step. For both of the models, the angle made by the axis of symmetry of the ellipse with the coordinate axis is equal to θ, the combined magnetic angle. The ratio between the lengths of the major and minor axes of the ellipse is directly related to the width‐to‐depth ratio of the dike or the bottom‐to‐top depth ratio of the vertical step. A few characteristic points defined on the ellipse are used to evaluate the body parameters. The major portion of the ellipse is obtained in the close vicinity of the source. Because of symmetry, the ellipse may be extrapolated easily outside the data length, and hence the effect of noise caused by adjacent objects is kept at a minimum.

scholarly journals Two Dimensional Modeling of Basaltic Rocks Intrusion Based on The Local Magnetic Anomalies Data in Jatilawang District Banyumas Regency

2020 ◽  
Vol 10 (2) ◽  
pp. 171
Author(s):  
Sehah Sehah ◽  
Sukmaji Anom Raharjo ◽  
Urip Nurwijayanto Prabowo
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Anomalies ◽  
Basaltic Rock ◽  
Research Area ◽  
Magnetic Data ◽  
Two Dimensional ◽  
Basaltic Rocks ◽  
Dimensional Modeling ◽  
Susceptibility Contrast ◽  
Lateral Length

Two dimensional modeling to basaltic rocks intrusion in Pekuncen and Karanglewas Villages Jatilawang District, Banyumas Regency, Central Java based on the local magnetic anomalies data has been carried out in March – June 2020. The amount of magnetic data obtained from the acquisition in the field was 239 data stretching in position of 109.107222° – 109.134944°E and 7.561361° – 7.577306°S, with the local magnetic anomalies values ranging of -2,961.11 – 1,516.31 nT. To model anomalous sources in the subsurface in two dimensions, then the local magnetic anomalies data is transformed into pseudogravity anomalies data, so that anomalous value can be obtained as -27.815 – 41.087 mGal. Based on the pseudogravity anomalous map, the basaltic rock intrusion is interpreted to be located in the eastern part of the research area, so modeling of anomalous sources is conducted in this area. The results of 2D-modeling to local magnetic anomalies data indicate the presence of anomalous object interpreted as basaltic rock intrusion with magnetic susceptibility contrast value of 0.0223 cgs, located at depth of 52.61 – 505.97 m and a lateral length of 1777.94 m. This rock intrudes sediment rock from the Halang Formation and is connected to other basaltic rock near the surface with magnetic susceptibility contrast value of 0.0165 cgs, located at depth of 1.94 – 80.90 m and lateral length of 751.83 m. The results of lithological interpretation are in accordance with the geological information of the research area.

Individualizing women’s suit patterns using body measurements from two-dimensional images

2016 ◽  
Vol 87 (6) ◽  
pp. 669-681 ◽  
Author(s):  
Bingfei Gu ◽  
Guolian Liu ◽  
Bugao Xu
Keyword(s):  
Prediction Models ◽  
The Body ◽  
Body Measurements ◽  
Two Dimensional ◽  
Subjective Test ◽  
Visual Evaluation ◽  
Body Dimensions ◽  
Clothing Fit ◽  
Body Shapes ◽  
2D Images

The goal of this study was to develop an approach that could automatically generate the customized patterns for women’s suits based on the body measurements taken from two-dimensional (2D) frontal and side images of a subject. The 26 important pattern dimensions relevant to certain body dimensions were first chosen, and the mapping relationships between the body and pattern dimensions were then established for pattern alterations. For the body dimensions (e.g. girths) that could not be directly measured in the 2D images, prediction models were created based on the available width and depth measurements. The body measurements from the 2D images (auto-measurements) of 295 subjects were compared with the corresponding manual measurements, which showed a good correlation between the auto and manual measurements. The try-on test of five suits made with the altered patterns demonstrated the good fitting effects of the customized suits at important characteristic landmarks of five participating subjects through a visual evaluation. The subjective test also showed a satisfactory result of clothing fit under five different postures. Since this pattern-making method is originated from the relationship between the features of a human body and the elements of a pattern prototype, the generated patterns are individualized by unique body shapes to attain a good fit. This method can also accelerate the pattern-making process, reducing human efforts, costs, and production time.

END CORRECTIONS IN MAGNETIC PROFILE INTERPRETATION

Geophysics ◽  
1973 ◽  
Vol 38 (3) ◽  
pp. 507-512 ◽  
Author(s):  
R. T. Shuey ◽  
A. S. Pasquale
Keyword(s):  
Magnetic Anomalies ◽  
The Body ◽  
Two Dimensional ◽  
Total Field ◽  
Magnetic Profile ◽  
Arbitrary Magnetization ◽  
End Corrections

Simple expressions are presented for the vertical and total field magnetic anomalies due to a polygonal body of finite strike length and arbitrary magnetization. These formulas incorporate end corrections into the well‐known Talwani‐Heirtzler (1964) formulas for two‐dimensional polygonal bodies and reduce to the latter for large strike length. Because of their simplicity, the formulas with end corrections lend themselves to rapid use in digital interpretation. Analysis of the formulas shows that interpretation with end corrections gives a body which is deeper and has a larger magnetization and different shape than the body inferred without end corrections.

A simple method for the analysis of magnetic anomalies over dike‐like bodies

Geophysics ◽  
1986 ◽  
Vol 51 (5) ◽  
pp. 1119-1126 ◽  
Author(s):  
H. V. Ram Babu ◽  
V. Vijayakumar ◽  
D. Atchuta Rao
Keyword(s):  
Maximum Amplitude ◽  
Magnetic Anomalies ◽  
The Body ◽  
Total Amplitude ◽  
Magnetization Direction ◽  
Simple Method ◽  
Aeromagnetic Anomalies ◽  
Susceptibility Contrast ◽  
Minimum Amplitude ◽  
The Relationship

Magnetic anomalies may be simply analyzed using a dike model. In this model, the depth to the source is approximately 1.25 S, where S is the straight‐slope distance measured on the steepest flank. The dip of the body may be evaluated from θ, the combined magnetic angle found from the ratio of the maximum amplitude to the minimum amplitude. In the presence of remanence, the body dip δ may be found from θ only when the direction of resultant magnetization is either known or assumed, and magnetization direction may be found only if the dip is known. The minimum susceptibility contrast k of the source may be calculated from the total amplitude A and intensity T of the inducing field using the relationship k = 0.3 A/T. A large number of aeromagnetic anomalies have been interpreted using this method. A few such anomalies are presented here to illustrate the applicability of the method.

A LEAST‐SQUARES METHOD OF INTERPRETING MAGNETIC ANOMALIES CAUSED BY TWO‐DIMENSIONAL STRUCTURES

Geophysics ◽  
1969 ◽  
Vol 34 (1) ◽  
pp. 65-74 ◽  
Author(s):  
William W. Johnson
Keyword(s):  
Least Squares ◽  
Least Squares Method ◽  
Nonlinear Least Squares ◽  
Magnetic Anomalies ◽  
Descent Method ◽  
The Body ◽  
Steepest Descent Method ◽  
Two Dimensional ◽  
Gauss Method ◽  
Least Squares Estimates

The equations relating the magnetic anomalies to the shape and susceptibility of a body are nonlinear with respect to the coordinates describing the shape. Therefore, iterative procedures must be used to obtain least‐squares estimates of the body coordinates. One method in general use for obtaining nonlinear least‐squares estimates is the Gauss method. This method often fails when the initial values for the structures and susceptibilities do not adequately account for the magnetic anomalies. Another method known as the steepest descent method generally converges to a solution; however, a large number of iterations are required. A method suggested by Marquardt (1963) incorporates the best features of the previous methods. In this paper the Marquardt method is applied to the interpretation of magnetic anomalies. For this purpose the two‐dimensional formulas derived by Talwani and Heirtzler (1964) are used to relate the geometry of a body to the resulting magnetic anomalies. The procedure efficiently controls the amount of change made to an interpreted structure at each iteration, assuring rapid convergence to a solution which satisfies the observed data better in the least‐squares sense than does the initial solution. The method is applied to representative problems.

‘A pinch of unseen, unguarded dust’: The World and Self in Thomas Hardy's Poems

2018 ◽  
Vol 8 (1) ◽  
pp. 49-66
Author(s):  
Monika Szuba
Keyword(s):  
The Body ◽  
The Self ◽  
Phenomenological Philosophy ◽  
The Earth ◽  
The World ◽  
The Universe ◽  
Recurrent Theme ◽  
Body Subject

The essay discusses selected poems from Thomas Hardy's vast body of poetry, focusing on representations of the self and the world. Employing Maurice Merleau-Ponty's concepts such as the body-subject, wild being, flesh, and reversibility, the essay offers an analysis of Hardy's poems in the light of phenomenological philosophy. It argues that far from demonstrating ‘cosmic indifference’, Hardy's poetry offers a sympathetic vision of interrelations governing the universe. The attunement with voices of the Earth foregrounded in the poems enables the self's entanglement in the flesh of the world, a chiasmatic intertwining of beings inserted between the leaves of the world. The relation of the self with the world is established through the act of perception, mainly visual and aural, when the body becomes intertwined with the world, thus resulting in a powerful welding. Such moments of vision are brief and elusive, which enhances a sense of transitoriness, and, yet, they are also timeless as the self becomes immersed in the experience. As time is a recurrent theme in Hardy's poetry, this essay discusses it in the context of dwelling, the provisionality of which is demonstrated in the prevalent sense of temporality, marked by seasons and birdsong, which underline the rhythms of the world.

Epilogue

2017 ◽  
Author(s):  
Joshua S. Walden
Keyword(s):  
The Body ◽  
The Self ◽  
The Individual ◽  
Relationship Of ◽  
The Relationship

The book’s epilogue explores the place of musical portraiture in the context of posthumous depictions of the deceased, and in relation to the so-called posthuman condition, which describes contemporary changes in the relationship of the individual with such aspects of life as technology and the body. It first examines Alfred Hitchcock’s Vertigo to view how Bernard Herrmann’s score relates to issues of portraiture and the depiction of the identity of the deceased. It then considers the work of cyborg composer-artist Neil Harbisson, who has aimed, through the use of new capabilities of hybridity between the body and technology, to convey something akin to visual likeness in his series of Sound Portraits. The epilogue shows how an examination of contemporary views of posthumous and posthuman identities helps to illuminate the ways music represents the self throughout the genre of musical portraiture.

scholarly journals Circular quiver gauge theories, isomonodromic deformations and $$W_N$$ fermions on the torus

2021 ◽  
Vol 111 (3) ◽  
Author(s):  
Giulio Bonelli ◽  
Fabrizio Del Monte ◽  
Pavlo Gavrylenko ◽  
Alessandro Tanzini
Keyword(s):  
Integrable System ◽  
Gauge Theories ◽  
The Self ◽  
Free Fermion ◽  
Two Dimensional ◽  
Isomonodromic Deformation ◽  
Specific Time ◽  
Dimensional Torus ◽  
Isomonodromic Deformations ◽  
Deformation Problem

AbstractWe study the relation between class $$\mathcal {S}$$ S theories on punctured tori and isomonodromic deformations of flat SL(N) connections on the two-dimensional torus with punctures. Turning on the self-dual $$\Omega $$ Ω -background corresponds to a deautonomization of the Seiberg–Witten integrable system which implies a specific time dependence in its Hamiltonians. We show that the corresponding $$\tau $$ τ -function is proportional to the dual gauge theory partition function, the proportionality factor being a nontrivial function of the solution of the deautonomized Seiberg–Witten integrable system. This is obtained by mapping the isomonodromic deformation problem to $$W_N$$ W N free fermion correlators on the torus.

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