Effect of microstructure and microchemistry on improvement of hydration and slag attack resistance of ilmenite-doped refractory limestone     

Abdel Monem Soltan  Mohamed Serry 《Mineralogy and Petrology》2015,109(1):35-44

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Surface evidences supporting a probable new concept for the river systems evolution in Egypt: a remote sensing overview     

Abotalib Z. Abotalib  Ramadan S. A. Mohamed 《Environmental Earth Sciences》2013,69(5):1621-1635

Compilation between the previous studies about the river systems evolution and integrating them with the remotely sensed data-based landscape analysis provide a new vision to the river systems evolution in Egypt during the Cenozoic Era. Relics of geomorphologic features left in the old basins related to these rivers suggest the existence of a natural dam between Nag Hammadi City and Wadi El-Assuiti. This barrier was separating two river systems during Late Miocene time: (1) the Qena River System and (2) the newly suggested North Egypt River System. The North Egypt River is supposed to be started by the Wadi El-Assuiti drainage basin, which flowed first in a westward direction, from its source in the Eastern Limestone Plateau to continue in a northward direction across the Nile Canyon (along the course of the Nile) to join the drainage system of Wadi Tarfa and Wadi Sannur and to end, finally, in the depression of Wadi El-Natrun to constitute the Wadi El-Natrun Miocene Delta. The present interpretation on the existence of a North Egypt River System, with the presence of an old natural dam to the south of Nag Hammadi City, necessitates a revision of the concepts used for groundwater exploration in Upper Egypt.  相似文献   

Impacts of future climate on the hydrology of a northern headwaters basin and its implications for a downstream deltaic ecosystem     

Prabin Rokaya  Daniel L. Peters  Mohamed Elshamy  Sujata Budhathoki  Karl-Erich Lindenschmidt 《水文研究》2020,34(7):1630-1646

Anthropogenic and climatic-induced changes to flow regimes pose significant risks to river systems. Northern rivers and their deltas are particularly vulnerable due to the disproportionate warming of the Northern Hemisphere compared with the Southern Hemisphere. Of special interest is the Peace–Athabasca Delta (PAD) in western Canada, a productive deltaic lake and wetland ecosystem, which has been recognized as a Ramsar site. Both climate- and regulation-induced changes to the hydrological regime of the Peace River have raised concerns over the delta's ecological health. With the damming of the headwaters, the role of downstream unregulated tributaries has become more important in maintaining, to a certain degree, a natural flow regime, particularly during open-water conditions. However, their flow contributions to the mainstem river under future climatic conditions remain largely uncertain. In this study, we first evaluated the ability of a land-surface hydrological model to simulate hydro-ecological relevant indicators, highlighting the model's strengths and weaknesses. Then, we investigated the streamflow conditions in the Smoky River, the largest unregulated tributary of the Peace River, in the 2071–2100 versus the 1981–2010 periods. Our modelling results revealed significant changes in the hydrological regime of the Smoky River, such as increased discharge in winter (+190%) and spring (+130%) but reduced summer flows (−33%) in the 2071–2100 period compared with the baseline period, which will have implications for the sustainability of the downstream PAD. In particular, the projected reductions in 30-day and 90-day maximum flows in the Smoky River will affect open-water flooding, which is important in maintaining lake levels and connectivity to perimeter delta wetlands in the Peace sector of the PAD. The evaluation of breakup and freeze-up flows for the 2071–2100 period showed mixed implications for the ice-jam flooding, which is essential for recharging high-elevation deltaic basins. Thus, despite projected increase in annual and spring runoff in the 2071–2100 period from the Smoky sub-basin, the sustainability of the PAD still remains uncertain.  相似文献   

Voronoi Meshing to Accurately Capture Geological Structure in Subsurface Simulations     

LaForce  Tara  Ebeida  Mohamed  Jordan  Spencer  Miller  Terry A.  Stauffer  Philip H.  Park  Heeho  Leone  Rosie  Hammond  Glenn 《Mathematical Geosciences》2023,55(2):129-161

Mathematical Geosciences - Mesh generation lies at the interface of geological modeling and reservoir simulation. Highly skewed or very small grid cells may be necessary to accurately capture the...  相似文献   

Insights on the small tsunami from January 28, 2020, Caribbean Sea MW7.7 earthquake by numerical simulation and spectral analysis     

Xu  Zhiguo  Sun  Lining  Rahman  Mohd Nashriq Abd  Liang  Shanshan  Shi  Jianyu  Li  Hongwei 《Natural Hazards》2022,111(3):2703-2719

A major left-lateral strike-slip Mw7.7 earthquake occurred in the vicinity of the Caribbean Sea on January 28, 2020. As a result, a small-scale tsunami was generated. The properties of the seismogenic source were described using observational data gathered for the earthquake and tsunami, as well as information on the regional tectonic setting. The tsunami was simulated with the COMCOT model and Okada’s dislocation model from finite fault solutions for M_W7.7 Caribbean Sea earthquakes published by the United States Geological Survey. The simulation results were compared to tide gauge records to validate whether the seafloor’s vertical displacement generated by the strike-slip fault caused a small-scale tsunami. We conducted a spectral analysis of the tsunami to better understand the characteristics of tsunami records. The tsunami simulation results showed that the co-seismic vertical displacement caused by a strike-slip M_W7.7 earthquake could have contributed to the small-scale tsunami, but the anomalously large high-frequency tsunami waves recorded by the George Town tide gauge 11 min after the earthquake were unrelated to the earthquake-generated tsunami. According to the spectrum analysis, the predominant period of noticeable high-frequency tsunami waves recorded by the George Town tide gauge occurred only two minutes after the earthquake. This indicates that the source of the small-scale tsunami was close to the George Town station and the possible tsunami source was 150 km away from George Town station. These facts suggest that a submarine landslide was caused by the strike-slip earthquake. The comprehensive analysis showed that the small-scale tsunami was not caused solely by co-seismic seafloor deformation from the strike-slip event but that an earthquake-triggered submarine landslide was the primary cause. Therefore, the combined impact of two sources led to the small-scale tsunami.

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Ecohydrology and flood risk management under climate vulnerability in relation to the sustainable development goals (SDGs): a case study in Nagaa Mobarak Village,Egypt     

Aly  Marwa M.  Refay  Neveen H.  Elattar  Hoda  Morsy  Karim M.  Bandala  Erick R.  Zein  Samir A.  Mostafa  Mohamed K. 《Natural Hazards》2022,111(2):1107-1119

Natural Hazards - This article aims to provide a thorough assessment of water quality and quantity incorporating the estimation of future patterns as a result of climate change from economic,...  相似文献   

Mapping Structurally Controlled Alterations Sparked by Hydrothermal Activity in the Fatira–Abu Zawal Area, Eastern Desert, Egypt     

Mohamed BADAWI  Mahmoud ABDELATIF  Ali SHEBL  Farid MAKROUM  Ahmed SHALABY  Norbert NEMETH 《《地质学报》英文版》2023,97(2):662-680

The Eastern Desert of Egypt suffered a protracted period of deformation triggered by cratonization of the new juvenile crust known as the Arabian Nubian Shield (ANS), which has been proposed for potential gold discoveries associated with the corresponding tectonic event. The Fatira area, on the border of Egypt''s Northern and Central Eastern Deserts, is covered with metavolcanic rocks twisted by a dextral relocation of the Fatira Shear Zone (FSZ) relative to the Barud magmatic body. The recent study evaluated many deformed post-orogenic granitic intrusions and felsite dikes associated with promising mineralization localities, notably orogenic gold deposits. The combination of various field observations and remote sensing data, followed by the analysis of aeromagnetic enhanced maps, allowed the differentiation of distinct lithologies, structural features, and hydrothermal alterations in the study area. Additionally, the integrated results obtained from the different interpretation techniques are utilized to identify and confirm the previously supposed mineralized localities in the Fatira and Abu Zawal areas and predict other matched localities. The final ASTER, Sentinel 2 hydrothermal alteration, and orientation entropy heat maps demonstrate the association between these mineralized regions and major structures related to the FSZ late stage of deformation rather than other structures studied throughout the area of interest.  相似文献   

Three-dimensional finite element analysis of spatially variable PVD improved ground     

Mohammad Wasiul Bari  Mohamed A. Shahin 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2015,9(1):37-48

A stochastic approach that investigates the effects of soil spatial variability on stabilisation of soft clay via prefabricated vertical drains (PVDs) is presented and discussed. The approach integrates the local average subdivision of random field theory with the Monte Carlo finite element (FE) technique. A special feature of the current study is the investigation of impact of spatial variability of soil permeability and volume compressibility in the smear zone as compared to that of the undisturbed zone, in conjunction with uncoupled three-dimensional FE analysis. A sensitivity analysis is also performed to identify the random variable that has the major contribution to the uncertainty of the degree of consolidation achieved via PVDs. The results of this study indicate that the spatial variability of soil properties has a significant impact on soil consolidation by PVDs; however, the spatial variability of soil properties in the smear zone has a dominating impact on soil consolidation by PVDs over that of the undisturbed zone. It is also found that soil volume compressibility has insignificant contribution to the degree of consolidation estimated by uncoupled stochastic analysis.  相似文献   

Morphotectonic and Morphodynamic investigations revealed by isobase surfaces analysis and derived differential mapping using GIS,Teboursouk area,northern Tunisia     

Tarek Slama  Benoit Deffontaines  Mohamed Moncef Turki 《Earth Science Informatics》2015,8(4):759-773

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Diachronic evolution of wetlands in a desert arid climate of the basin of Ouargla (southeastern Algeria) between 1987 and 2009 by remote sensing     

Fethi Medjani  Oualid Hamdaoui  Mohamed Djidel  Danielle Ducrot 《Arabian Journal of Geosciences》2015,8(12):10181-10192

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