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.

Gravity interpretation using the Mellin transform

Geophysics ◽  
1986 ◽  
Vol 51 (1) ◽  
pp. 114-122 ◽  
Author(s):  
N. L. Mohan ◽  
L. Anandababu ◽  
S. V. Seshagiri Rao
Keyword(s):  
Circular Cylinder ◽  
Gravity Anomaly ◽  
Mellin Transform ◽  
The Body ◽  
Two Dimensional ◽  
Gravity Effect ◽  
Horizontal Derivative ◽  
Gravity Interpretation ◽  
Body Parameters ◽  
Horizontal Circular Cylinder

The Mellin transform of the gravity effect of a buried sphere and two‐dimensional horizontal circular cylinder, and the first horizontal derivative of the gravity effect of a two‐dimensional thin fault layer are derived. The transformed functions are bounded by two asymptotes. They are analyzed and procedures are formulated excluding the asymptotic regions for the extraction of the body parameters. The application of the Mellin transform is tested on simulated models as well as on two field examples: (1) the Humble Dome gravity anomaly near Houston, USA; and (2) the Louga gravity anomaly, USA.

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 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.

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.

The use of Body Surface Index as a Better Clinical Health indicators Compare to Body Mass Index and Body Surface Area for Clinical Application

2018 ◽  
pp. 131-136
Author(s):  
Shirazu I. ◽  
Theophilus. A. Sackey ◽  
Elvis K. Tiburu ◽  
Mensah Y. B. ◽  
Forson A.
Keyword(s):  
Surface Area ◽  
Body Surface Area ◽  
Clinical Application ◽  
Body Surface ◽  
Body Height ◽  
Health Indicators ◽  
The Body ◽  
Body Parameters ◽  
The Relationship ◽  
Individual Body

The relationship between body height and body weight has been described by using various terms. Notable among them is the body mass index, body surface area, body shape index and body surface index. In clinical setting the first descriptive parameter is the BMI scale, which provides information about whether an individual body weight is proportionate to the body height. Since the development of BMI, two other body parameters have been developed in an attempt to determine the relationship between body height and weight. These are the body surface area (BSA) and body surface index (BSI). Generally, these body parameters are described as clinical health indicators that described how healthy an individual body response to the other internal organs. The aim of the study is to discuss the use of BSI as a better clinical health indicator for preclinical assessment of body-organ/tissue relationship. Hence organ health condition as against other body composition. In addition the study is `also to determine the best body parameter the best predict other parameters for clinical application. The model parameters are presented as; modeled height and weight; modelled BSI and BSA, BSI and BMI and modeled BSA and BMI. The models are presented as clinical application software for comfortable working process and designed as GUI and CAD for use in clinical application.

Representation of a Human Body: A Comparison Study between Balinese and Javanese Traditional House

Humaniora ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 83-90
Author(s):  
Anak Agung Ayu Wulandari ◽  
Ade Ariyani Sari Fajarwati
Keyword(s):  
Comparative Study ◽  
Human Body ◽  
Qualitative Method ◽  
Descriptive Analysis ◽  
The Body ◽  
Comparison Study ◽  
Architectural Drawing ◽  
Study Approach ◽  
The Comparative Study ◽  
Head Area

The research would look further at the representation of the human body in both Balinese and Javanese traditional houses and compared the function and meaning of each part. To achieve the research aim, which was to evaluate and compare the representation of the human body in Javanese and Balinese traditional houses, a qualitative method through literature and descriptive analysis study was conducted. A comparative study approach would be used with an in-depth comparative study. It would revealed not only the similarities but also the differences between both subjects. The research shows that both traditional houses represent the human body in their way. From the architectural drawing top to bottom, both houses show the same structure that is identical to the human body; head at the top, followed by the body, and feet at the bottom. However, the comparative study shows that each area represents a different meaning. The circulation of the house is also different, while the Balinese house is started with feet and continued to body and head area. Simultaneously, the Javanese house is started with the head, then continued to body, and feet area.

scholarly journals Spinning rough disc moving in a rarefied medium

2010 ◽  
Vol 466 (2119) ◽  
pp. 2033-2055 ◽  
Author(s):  
Alexander Plakhov ◽  
Tatiana Tchemisova ◽  
Paulo Gouveia
Keyword(s):  
The Body ◽  
Two Dimensional ◽  
Zero Temperature ◽  
Optimal Mass Transport ◽  
Dense Gases ◽  
Magnus Effect ◽  
Inverse Effect ◽  
Transversal Force ◽  
The Moment ◽  
Complementary Mechanism

We study the Magnus effect: deflection of the trajectory of a spinning body moving in a gas. It is well known that in rarefied gases, the inverse Magnus effect takes place, which means that the transversal component of the force acting on the body has opposite signs in sparse and relatively dense gases. The existing works derive the inverse effect from non-elastic interaction of gas particles with the body. We propose another (complementary) mechanism of creating the transversal force owing to multiple collisions of particles in cavities of the body surface. We limit ourselves to the two-dimensional case of a rough disc moving through a zero-temperature medium on the plane, where reflections of the particles from the body are elastic and mutual interaction of the particles is neglected. We represent the force acting on the disc and the moment of this force as functionals depending on ‘shape of the roughness’, and determine the set of all admissible forces. The disc trajectory is determined for several simple cases. The study is made by means of billiard theory, Monge–Kantorovich optimal mass transport and by numerical methods.

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