Erratum to “The Berit transect of the Tauride thrust belt, S Turkey: Late Cretaceous–Early Cenozoic accretionary/collisional processes related to closure of the Southern Neotethys” [Journal of Asian Earth Sciences 27 (2006) 108–145]     

Alastair H.F. Robertson  Timur Ustamer  Osman Parlak  Ulvi Can Ünlügen  Kemal Tal&#x;  Nurdan &#x;nan 《Journal of Asian Earth Sciences》2007,29(5-6):978-980

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Expansion of the first order planetary disturbing function by Smart's method     

Osman M. Kamel  Adel S. Soliman 《Earth, Moon, and Planets》1990,48(2):165-170

In this part we expand the indirect part of the planetary perturbing function by Smart's method, via Taylor's theorem. We neglect, in our expansion, terms of degree higher than the fourth with regard to the eccentricities and tangents of the inclinations.  相似文献   

Stellar Population Analysis of Galaxies based on Genetic Algorithms     

Abdel-Fattah Attia  H. A. Ismail  I. M. Selim  A. M. Osman  I. A. Isaa  M. A. Marie  A. A. Shaker 《中国天文和天体物理学报》2005,5(4):347-355

We present a new method for determining the age and relative contribution of different stellar populations in galaxies based on the genetic algorithm. We apply this method to the barred spiral galaxy NGC 3384, using CCD images in U, B, V, R and I bands. This analysis indicates that the galaxy NGC 3384 is mainly inhabited by old stellar population (age >109yr). Some problems were encountered when numerical simulations are used for determining the contribution of different stellar populations in the integrated color of a galaxy. The results show that the proposed genetic algorithm can search efficiently through the very large space of the possible ages.  相似文献   

Response of a tunnel deeply embedded in a viscoelastic medium     

Thomas J. Birchall  Ashraf S. Osman 《国际地质力学数值与分析法杂志》2012,36(15):1717-1740

This paper presents a three‐dimensional energy‐based solution for the time‐dependent response of a deeply embedded and unsupported semi‐infinite tunnel of circular cross‐section. The tunnel is taken to be excavated quasi‐instantaneously from an infinite rock body that initially exhibits an isotropic stress state and that is made up of a homogeneous, isotropic and viscoelastic material. The viscoelastic behaviour is modelled by means of Burger's model, and the rock is taken to behave volumetrically linear elastic and to exhibit exclusively deviatoric creep. This viscoelastic problem is transformed into the Laplace domain, where it represents a quasi‐elastic problem. The displacement fields in the new solution are taken to be the products of independent functions that vary in the radial and longitudinal directions. The differential equations governing the displacements of the system and appropriate boundary conditions are obtained using the principle of minimum potential energy. The solutions for these governing equations in the Laplace domain are then obtained analytically and numerically using a one‐dimensional finite difference technique. The results are then transformed back into the time domain using an efficient numerical scheme. The accuracy of the new solution is comparable with that of a finite element analysis but requires much less computation effort. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Flood risk assessment for urban water system in a changing climate using artificial neural network   总被引：1，自引：0，他引：1  

M. Abdellatif  W. Atherton  R. Alkhaddar  Y. Osman 《Natural Hazards》2015,79(2):1059-1077

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The relationship between lithological and geomechanical properties of tight carbonate rocks from Upper Jubaila and Arab-D Member outcrop analog,Central Saudi Arabia     

Ammar Abdlmutalib  Osman Abdullatif  Gabor Korvin  Abdulazeez Abdulraheem 《Arabian Journal of Geosciences》2015,8(12):11031-11048

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Fourier analysis of the light curves of eclipsing variables,XVI     

Osman Demircan 《Astrophysics and Space Science》1978,56(2):453-472

The practical procedures for the solutions of the elements of any eclipsing system in the frequency-domain have been described in a previous paper of this series (Kopal and Demircan, 1978, Paper XIV). The fundamental quantities from which we depart in quest of our solution are twog-functions defining by the momentsA _2m (see Equations (2.13)–(2.16) in Paper XIV, or Equations (3.2)–(3.6) in Paper XV: Demircan, 1978b). If we establish the observational values for these functions, they constitute two independent relations between the unknown parametersa andc _o, and can be numerically solved for them with the aid of the general expressions for the respective moments. However, the determinacy of these parameters depends on not only the accuracy of observations but also the employedg-functions. For better understanding of the geometrical determinacy of the eclipse parametersa andc _o, different combinations of the momentsA _2m have been worked out asg-functions. For the index 2m, the values between 0 and 6 were applied. It has been noted that the behaviour of these functions vary but very little with applied different combinations of the moments. A choice of the most convenient moments to obtain a good determinacy for the eclipse elements were discussed. In this connection, (i) them-dependence of the moments, and the errors in their observational values have been considered, (ii) different practical procedures for the solution of eclipse elements were introduced, and (iii) different type of moments were tested.  相似文献   

A second-order Uranus-Neptune theory by Hori's method     

Osman M. Kamel 《Earth, Moon, and Planets》1988,40(2):119-147

We shall establish a second order - with respect to a small parameter which is of the order of planetary masses - Uranus-Neptune canonical planetary theory. The construction will be through the Hori-Lie perturbation theory. We perform the elliptic expansions by hand, taking into account powers 0, 1, 2 of the eccentricity-inclination. Only the principal part of the planetary Hamiltonian will be taken into consideration. Our theory will be expressed in terms of the canonical variables of Henri Poincaré, referring the planetary coordinates to the Jacobi-Radau system of origin. Only U- N critical terms will be assumed as the periodic terms.  相似文献   

A second order Jupiter-Saturn planetary theory     

Osman M. Kamel  Abdel Aziz Bakry 《Earth, Moon, and Planets》1982,27(4):417-430

We present a second order secular Jupiter-Saturn planetary theory through Poincaré canonical variables, von Zeipel's method and Jacobi-Radau referential. We neglect in our expansions terms of power higher than the fourth with respect to eccentricities and sines of inclinations. We assume that the disturbing function is composed of secular and critical terms only. We shall deriveF _2si and writeF _2s in terms of Poincaré canonical variables in Part II of this problem.  相似文献   

Detailed isophotometry of some galaxies,I     

A. I. Gamal el Din  I. A. Issa  A. M. I. Osman  F. Y. Kamal 《Astrophysics and Space Science》1992,190(1):67-88

Results from a detailed isophotometric survey of NGC 5595, NGC 5597, NGC 5605, and NGC 7769 are given. It includes isophotic maps, luminosity profiles and ellipticity curves as well. Scanning of these galaxies was done in theB andV colours.  相似文献