Distribution of nickel in a polluted mangrove habitat of the Indus Delta     

Saifullah SM  Khan SH  Ismail S 《Marine pollution bulletin》2002,44(6):570-576

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Least-squares optimum-order regional geothermal gradient determination from deep borehole temperature data with application to the Western Desert of Egypt     

E. M. Abdelrahman  H. M. El-Araby  B. El-Hakim  A. I. Bayoumi  A. M. Ismail 《Studia Geophysica et Geodaetica》1993,37(3):302-314

Summary This paper discusses an approach to determining the least-squares optimum order of a polynomial fit to temperature-gradient data. The optimum is reached when two successive least-squares regional maps are sufficiently similar. This similarity is measured by the correlation factor between the polynomials.The approach was applied to the available deep bore-hole temperature data in the central part of the Northern Western Desert of Egypt. The fitting polynomial was found to be of the second degree. Assuming the thermal conductivity to be uniformly 2·2 Wm^–1K^–1 for the stratigraphic section in the Western Desert, the heat-flow density ranges between 35 and 70 mW/m².Presented at the International Meeting on Terrestrial Heat Flow and the Structure of Lithosphere, Bechyn Castle, Czech Republic, September 2 – 7, 1991.  相似文献   

WATER QUALITY STUDIES IN MALAYSIAN DISUSED MAN MADE LAKES FOR SUITABILITY OF AN AQUACULTURE PROJECT     

Azma Hanim Ismail  Mashhor Mansor  Wan Maznah W O 《湿地科学》2005,3(4)

1INTRODUCTIONWater is an essential component of an eco-sys-tem.It sustains life on the earth.A community de-pends on water for its domestic,agricultural and in-dustrials needs.According to Ackefors,et al.(1994),the term water quality'in the context ofaqua…  相似文献   

In-situ investigation on real-time suspended sediment measurement techniques: Turbidimetry,acoustic attenuation,laser diffraction (LISST) and vibrating tube densimetry     

David Felix  Ismail Albayrak  Robert Michael Boes 《国际泥沙研究》2018,33(1):3-17

Real-time measurements of Suspended Sediment mass Concentration(SSC) and Particle Size Distribution(PSD) are of prime importance for the investigation and management of fine-sediment related processes in surface water systems and hydraulic schemes. In a field study at the waterway of the hydropower plant(HPP) Fieschertal in the Swiss Alps, the real-time measurement performance of the following techniques and instruments were assessed based on measurements in the sediment seasons of the years 2013 and 2014:(1) turbidimetry,(2) single-frequency acoustic attenuation using a standard acoustic discharge measurement(ADM) installation,(3) laser diffraction(Laser In-Situ Scattering and Transmissometry, LISST), and(4) vibrating tube densimetry using a Coriolis Flow and Density Meter(CFDM).Reference SSCs were obtained from gravimetric analysis of 219 automatically pumped water samples.LISST additionally supplied PSD every minute. The median particle diameter, d_(50), was usually 15μm and increased occasionally to 100μm. The turbidimeter and the ADM underestimated the SSC when the transported particles were coarser than usual. Such temporary biases resulted from the poor correlation between d_(50) and SSC at this study site. The SSCs from CFDM and LISST were not or less biased by PSD variations. Mainly due to angular and flaky particle shapes, SSC from LISST needed a correction by 79% on average. With the usually prevailing silt particles, an optical path length of 5 mm and no dilution, the SSC measurement range of LISST was limited to about 1.5 g/l. The CFDM allowed measuring higher SSC than the other investigated instruments(e.g. up to 13.5 g/l). With a periodic offset correction, its relative SSC measurement uncertainty was 20% for SSC≥ 1.5 g/I. To reliably measure a wide range of SSC with temporarily variable PSD, a combination of instruments is recommended: e.g. a standard LISST, a CFDM,and an automatic water sampler for gravimetric reference measurements.  相似文献   

Multi scenario seismic hazard assessment for Egypt     

Shaimaa Ismail Mostafa  Abd el-aziz Khairy Abd el-aal  Mohamed Ahmed El-Eraki 《Journal of Seismology》2018,22(3):669-696

Egypt is located in the northeastern corner of Africa within a sensitive seismotectonic location. Earthquakes are concentrated along the active tectonic boundaries of African, Eurasian, and Arabian plates. The study area is characterized by northward increasing sediment thickness leading to more damage to structures in the north due to multiple reflections of seismic waves. Unfortunately, man-made constructions in Egypt were not designed to resist earthquake ground motions. So, it is important to evaluate the seismic hazard to reduce social and economic losses and preserve lives. The probabilistic seismic hazard assessment is used to evaluate the hazard using alternative seismotectonic models within a logic tree framework. Alternate seismotectonic models, magnitude-frequency relations, and various indigenous attenuation relationships were amended within a logic tree formulation to compute and develop the regional exposure on a set of hazard maps. Hazard contour maps are constructed for peak ground acceleration as well as 0.1-, 0.2-, 0.5-, 1-, and 2-s spectral periods for 100 and 475 years return periods for ground motion on rock. The results illustrate that Egypt is characterized by very low to high seismic activity grading from the west to the eastern part of the country. The uniform hazard spectra are estimated at some important cities distributed allover Egypt. The deaggregation of seismic hazard is estimated at some cities to identify the scenario events that contribute to a selected seismic hazard level. The results of this study can be used in seismic microzonation, risk mitigation, and earthquake engineering purposes.  相似文献