A FORTRAN-77 computer program for three-dimensional inversion of magnetic anomalies resulting from multiple prismatic bodies

1993 ◽  
Vol 19 (6) ◽  
pp. 781-801 ◽  
Author(s):  
D. Bhaskara Rao ◽  
N. Ramesh Babu
Keyword(s):  
Computer Program ◽  
Three Dimensional ◽  
Magnetic Anomalies ◽  
Prismatic Bodies ◽  
Fortran 77

A rapid method for three‐dimensional modeling of magnetic anomalies

Geophysics ◽  
1991 ◽  
Vol 56 (11) ◽  
pp. 1729-1737 ◽  
Author(s):  
D. Bhaskara Rao ◽  
N. Ramesh Babu
Keyword(s):  
Computing Time ◽  
Optimization Technique ◽  
Three Dimensional ◽  
Magnetic Anomalies ◽  
Total Field ◽  
Arbitrary Polarization ◽  
Three Dimensional Modeling ◽  
Prismatic Bodies ◽  
Forward Calculation ◽  
Approximate Equations

A computer program has been developed for three‐dimensional analysis of total field magnetic anomalies due to arbitrary polarization suitable for present‐day personal computers. A vertical sided prism with arbitrary polarization is used as a basic model. A nonlinear optimization technique based on Marquardt’s algorithm is used to estimate all parameters of the model. A combination of prisms is used to analyze more complex magnetic fields. Analytical methods are used to estimate the derivatives required in the simultaneous solutions of the normal equations. Methods have been developed to minimize the computing time in forward calculation as well as in inversion. Approximate equations have been derived for rapid calculation of magnetic anomalies and partial derivatives of anomalies of prismatic bodies, which are valid beyond short distances from the sources. The algorithm has been developed in such a way that the use of the exact and approximate equations may be efficiently monitored as a trade‐off between accuracy and speed. The method is applied to analyze a synthetic anomaly contour map and the total field aeromagnetic anomalies in the offshore region of Mahanadi basin, Orissa, India.

Analysis of magnetic field components anomalies due to homogeneous polyhedrons

2021 ◽  
Vol 39 (1) ◽  
Author(s):  
Eduardo Menezes de Souza Amarante ◽  
Edson Emanoel Starteri Sampaio
Keyword(s):  
Inverse Modeling ◽  
Three Dimensional ◽  
Magnetic Anomalies ◽  
Irregular Shapes ◽  
Local Coordinates ◽  
Prismatic Bodies ◽  
Para Determinar ◽  
Definition Of ◽  
Analytical Expressions ◽  
Polyhedral Bodies

ABSTRACT. A procedure for determining semi-analytical expressions for the magnetic fields caused by homogeneous polyhedral bodies based on Green's theorem has been developed. It constitutes a modification of previous developments for the gravity field of three-dimensional bodies and employs the discretization of the faces of the polyhedron by triangles and the definition of local coordinates for each triangle. A maximum misfit of less than 1.0\% between the values computed with these analytical expressions and those obtained with closed expressions for prismatic bodies, applied to a homogeneous cube, demonstrates the effectiveness of the procedure. Examples of magnetic maps due to octahedral bodies with different forms and orientations show that it is possible to obtain a qualitative distinction among their anomalies. Therefore, the present analysis constitutes a basis for future inverse modeling of convex polyhedrons and will be useful in geophysical exploration.Keywords: magnetic anomalies, polyhedral bodies, irregular shapes. Análise das componentes do campo magnético produzido por um poliedro homogêneoRESUMO. Foi desenvolvido um procedimento para determinar expressões analíticas para os campos magnéticos causados por corpos poliédricos homogêneos com base no teorema de Green. Constitui uma modificação dos desenvolvimentos anteriores para o campo gravitacional de corpos tridimensionais e emprega a discretização das faces do poliedro por triângulos e a definição das coordenadas locais para cada triângulo. Um erro máximo inferior a 1,0% entre os valores calculados com essas expressões analíticas e os obtidos com expressões fechadas para corpos prismáticos, aplicados a um cubo homogêneo, demonstra a eficácia do procedimento. Exemplos de mapas magnéticos devido a corpos octaédricos com diferentes formas e orientações mostram que é possível obter uma distinção qualitativa entre suas anomalias. Portanto, a presente análise constitui uma base para futura modelagem inversa de poliedros convexos e será útil na exploração geofísica.Palavras-chaves: anomalias magnéticas, corpos poliédricos, formas irregulares.

Three-dimensional computer program on horse digestive track

2002 ◽  
Vol 22 (5) ◽  
pp. 202-202
Author(s):  
Nasser Alidadi ◽  
Mohammad R. Mokhber Dezfouli ◽  
Mohammad Gholi Nadalian ◽  
Ali Rezakhani ◽  
Iradj Nouroozian
Keyword(s):  
Computer Program ◽  
Three Dimensional

The Analysis and Design of a Fire Engine Safety Cab Using Finite Element Methods

1977 ◽  
Vol 191 (1) ◽  
pp. 187-193 ◽  
Author(s):  
J. C. Miles ◽  
G. A. Wardill
Keyword(s):  
Finite Element ◽  
Computer Program ◽  
Three Dimensional ◽  
Analysis And Design ◽  
Vehicle Structure ◽  
Collapse Analysis ◽  
Incremental Formulation ◽  
Analysis Computer ◽  
Fire Engine ◽  
Analysis Computer Program

A three dimensional structural collapse analysis computer program is described, and illustrated by reference to a safety vehicle structure analysed and designed using the program. The particular problems of large displacements and material non-linearity are accounted for, and a method of estimating the permanent set which results after impact is described. Based on an incremental formulation of the conventional finite-element method, the computer program is capable of tracing the complete load deflection characteristics of a structure up to and beyond the point of collapse.

A Three-Dimensional Finite Difference Solution for the Thermal Stresses in Railcar Wheels

1969 ◽  
Vol 91 (3) ◽  
pp. 891-896 ◽  
Author(s):  
G. E. Novak ◽  
B. J. Eck
Keyword(s):  
Computer Program ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Transient Temperature ◽  
Shear Stresses ◽  
Radial Temperature ◽  
Closed Form Solutions ◽  
Brake Application ◽  
History Of ◽  
Thin Disks

A numerical solution is presented for both the transient temperature and three-dimensional stress distribution in a railcar wheel resulting from a simulated emergency brake application. A computer program has been written for generating thermoelastic solutions applicable to wheels of arbitrary contour with temperature variations in both axial and radial directions. The results include the effect of shear stresses caused by the axial-radial temperature gradients and the high degree of boundary irregularity associated with this type of problem. The program has been validated by computing thermoelastic solutions for thin disks and long cylinders; the computed values being in good agreement with the closed form solutions. Currently, the computer program is being extended to general stress solutions corresponding to the transient temperature distributions obtained by simulated drag brake applications. When this work is completed, it will be possible to synthesize the thermal history of a railcar wheel and investigate the effects of wheel geometry in relation to thermal fatigue.

ProgramCRYC3Dfor geometric computing in crystallography

2008 ◽  
Vol 41 (2) ◽  
pp. 479-480 ◽  
Author(s):  
Ludmila Urzhumtseva ◽  
Alexandre Urzhumtsev
Keyword(s):  
Computer Program ◽  
Three Dimensional ◽  
Teaching Tool ◽  
Online Help ◽  
Principal Mode ◽  
Geometric Characteristics ◽  
Simple Program ◽  
Or Groups ◽  
Geometric Objects ◽  
Everyday Work

The computer programCRYC3Dworks with three-dimensional crystallographic geometric objects or groups of them and calculates their basic geometric characteristics by a simple click in the menu. In particular, this includes vector operations in both direct and reciprocal spaces and cell transformations. Collecting basic crystallographic operations in a single and simple program helps crystallographers to avoid looking for `fast-and-dirty' scripts or using large and unwieldy packages and may be useful in everyday work. When running the program in its principal mode, macro-operations are accompanied by a list of elementary geometric operations. This feature, together with the presence of a single-command mode and online help, may be useful also as a teaching tool.

TABLES, a program to display space-group symmetry information in three dimensions

1987 ◽  
Vol 20 (6) ◽  
pp. 532-535 ◽  
Author(s):  
C. Abad-Zapatero ◽  
T. J. O'Donnell
Keyword(s):  
Computer Graphics ◽  
Computer Program ◽  
Three Dimensional ◽  
Spatial Location ◽  
Three Dimensions ◽  
Group Symmetry ◽  
Space Group ◽  
Interactive Display ◽  
Symmetry Operators ◽  
Group Information

TABLES is a computer program developed to display the crystal symmetry and the spatial location of the different symmetry operators for a given space group using interactive computer graphics. It allows the three-dimensional interactive display of the space-group information contained in International Tables for Crystallography [(1983), Vol. A. Dordrecht: Reidel]. Such a program is useful as a teaching aid in crystallography and is valuable for exploring molecular packing arrangements.

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