Analytical solution to the perturbedJ 2 motion of Artificial Satellite in terms of Euler parameters     

Mervat El-Sayed Awad 《Earth, Moon, and Planets》1995,69(1):1-12

In this paper an analytical solution for the differential equations governing the motion of Artificial Satellite under the oblateness of the earth will be developed. We start with the differential equations in terms of Euler parameters. To compact algebra, we introduce the Cayley-Klein type complex variables. Comparison between numerical and analytical final states withJ ₂ will be given for a test case.  相似文献   

Reply to burns' comments on “The search for standardized methods in analysis of environmental samples for hydrocarbons”     

H. Awad 《Marine Chemistry》1983,13(1):77-79

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Efficient algorithms for the earth's gravitational potential and its partial derivatives for satellite prediction     

Mohamed Adel Sharaf  Mervat El-Sayed Awad  Mona A. Banaja 《Earth, Moon, and Planets》1989,47(2):171-192

In this paper, economical recursion formulae for the Earth's gravitational potential and its partial derivatives with respect to the Cartesian coordinates, and time will be established for any number and any type of the harmonic coefficients. General computational algorithms for their implementations on digital computers are also given.Now at the Department of Astronomy, King Abdul-Aziz Univ., Jeddah, Saudi Arabia.Now at the Department of Mathematics, Girls College of Education, Jeddah, Saudi Arabia.  相似文献   

Seismicity and water level variations in the Lake Aswan area in Egypt 1982–1997     

Awad Hassoup 《Journal of Seismology》2002,6(4):459-467

The data described here are obtained from the continuous record of earthquakeactivity and lake water-level variation in the Lake Aswan area in Egypt between 1982 and 1997. The seismicity is monitored by a local telemetered seismograph network. The hypocentral parameters of earthquakes have been determined using Hypo71. The earthquake foci are distributed in two seismic zones, shallow and deep in the crust. Shallow events have focal depths of less than 10 km. Deep events extend from 10 to 30 km. The temporal sequence of seismicity iscorrelated with both the water-level variation and the average daily change of the water level in the lake Aswan. The temporal variation of the seismicityindicates that there are only six sequences of increased seismic activity during 1982–1997. The correlation between the seismic activity and the daily variation of the lake water level is poorly observed except with the June 1987 events swarm, which was accompanied by the presence of an anomaly in rate of water level decreasing. It is concluded that the increase in seismic activity in the Aswan reservoir is demonstrating an example of rapid reservoir-triggered seismicity. The deeper seismic sequence in this area, which was associated with the November 14, 1981 mainshock (M_D = 5.7), and the earlier seismicity (1981–82), has been correlated with a deeper high velocity anomaly (Awad and Mizoue, 1995-b).  相似文献   

Magnetic interpretation of long horizontal cylinders using correlation factors between successive least-squares residual anomaly profiles     

El-Sayed M. Abdelrahman 《Pure and Applied Geophysics》1990,132(3):521-532

Procedures are formulated using the correlation factors between successive least-squares residual magnetic anomaly profiles due to long horizontal cylinders for interpreting the three principal anomalies (vertical, horizontal, and total). It is demonstrated that correlation values can be used to determine the depth to the center of the buried structure and the index parameter. Procedures are also formulated to estimate the amplitude coefficient. Two worked examples using theoretical data show the effectiveness of the present method.  相似文献   

Book reviews     

El-Sayed  El-Bushra  J. A. Hellen  Hong-key Yoon  A. Wallner  C. A. Halstead  Gisela Prasad  Ernst H. Doerpinghaus/Altea  Ulrik Lohm  Ernst H. Doerpringhaus  Helmut Vidal  John M. Reynolds  Matthias Kuhle 《GeoJournal》1989,18(4):461-466

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The status of geography in Saudi universities with special reference to King Saud University     

El-Sayed El-Bushra Ph. D.  A. Hassan Ph. D. 《GeoJournal》1986,13(2):153-156

Although there are several departments and subdepartments of geography in Saudi universities and other institutions, these departments have so far failed to produce professionals who are capable of filling the posts offered by the employers in both the public and private sectors. This paper suggests that since the demand for geography graduates with general training is rather low at presents, it is time for geography departments to turn to professionalism in the field so that geography graduates can compete favourably for the available posts. This calls for a new look into the geography curriculum, particularly at university level with a view of improving the skills and aptitude of geographers to assume a more positive role in the process of development. The paper also calls for the regional specialisation of geography departments in Saudi Arabia as a step forward towards solving the existing job problem for geography graduates, as well aas underlining the involvement and commitment of geographers to issues of development at the local, regional and national scales.  相似文献   

Geological and hydrological investigation of a water collection system in arid Jordanian lands     

S. A. Taqieddin  A. S. Al-Homoud  A. Awad  S. Ayyash 《Environmental Geology》1995,26(4):252-261

With the increase in population of developing and under developed countries, and with the availability of water resources strained and in many areas deficient, it is quite evident that water conservation and distribution programs need to be adopted on a scale far greater than any yet in use. This requires a more detailed evaluation and development of any water resource. In this study, the geology and geomorphology of the Safawi area northeast of Jordan and the climatic conditions were evaluated as an aid in determining the potential for the collection of surface water. The runoff coefficient, flood frequency, and runoff volumes from some selected valleys were determined through the use of the Soil Conservation Service (SCS) method and other known techniques. The results of this study indicated that the collection of surface water in this arid region is feasible. Estimates were made for the runoff coefficient and annual runoff volumes through the application of the accepted hydraulic engineering methods.  相似文献   

A Preliminary Survey of the Nitrogen and Carbon Isotope Characteristics of Fish from the Lagoons of Egypt’s Nile Delta     

Autumn Oczkowski  Scott Nixon  Steve Granger  Abdel-Fattah M. El-Sayed  Mark Altabet  Richard McKinney 《Estuaries and Coasts》2008,31(6):1130-1142

The present study reports nitrogen and carbon stable isotope data (δ¹⁵N and δ¹³C) from four large (63–400 km²), shallow (∼1 m) coastal lagoons on Egypt’s Nile Delta. While the lagoons all receive sewage and agricultural drainage, the magnitude of loading varies. In this preliminary survey, we document wide variability in the δ¹⁵N and δ¹³C isotope values of major fish groups among these lagoons. There were no consistent or significant differences among the major groups of fish, including carp, catfish, mullet, and tilapia. There was a strong positive correlation (R ² = 0.84) between the average δ¹⁵N values of fish muscle and estimated water residence time among the lagoons. This preliminary evidence suggests that nitrogen cycle transformations may be more important than primary N source differences in determining N isotopic ratios of organisms in the lagoons. The δ¹³C results point to the probable importance of autochthonous particulate organic matter rather than terrestrial detritus or marine plankton in the diets of resident fish populations in the lagoons.  相似文献   

Spatial-based hydro-morphometric watershed modeling for the assessment of flooding potentialities     

Hossam H. Elewa  El-Sayed M. Ramadan  Ahmed M. Nosair 《Environmental Earth Sciences》2016,75(10):927

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