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51.
Brahim Abdelkader Ahmed Arab Marwan Sadek Isam Shahrour 《Geotechnical and Geological Engineering》2018,36(4):2077-2085
This paper presents the results of triaxial tests conducted for the investigation of the influence of geotextile on both the stress–strain and volumetric change behavior of reinforced sands. Tests were carried out on loose sand. The experimental program includes drained compression tests on samples reinforced with different values of both geotextile layers (1 ≤ Ng ≤ 3) and confining pressure (\(\upsigma_{\text{c}}^{\prime }\)) varying from 50 to 200 kPa. Tests show that the contribution of geotextile is negligible until an axial strain threshold that range between 2.5% for a confining pressure of 50 kPa to lower than 1% for 100 and 200 kPa confining pressure. At higher values of εa, geotextile induces a quasi-linear increase in the stress deviator (q) and volume contraction in the reinforced sand. Tests show a negligible influence of the number of geotextile layers (Ng) on the contribution of geotextile to both stress–strain and volumetric change, when normalized with Ng. Tests also show that the contribution of geotextile to the stress–strain mobilization augments with the increase in the confining pressure, while its contribution to the volume contraction decreases with the increase in the confining pressure. The reinforced soil becomes contracting in the case of 2 and 3 geotextile layers. 相似文献
52.
Salahuddin Nehal Abdelwahab Mohamed A. Akelah Ahmed Elnagar Marlen 《Natural Hazards》2021,105(2):1375-1394
Natural Hazards - The present investigation has highlighted the utility of floating aquatic Egyptian hyacinth, which is considered as a significant reason for environmental problems in Nile River,... 相似文献
53.
Emad Nagm Sreepat Jain Kamel Mahfouz Ahmed El-Sabbagh Aziz Abu Shama 《Proceedings of the Geologists' Association. Geologists' Association》2021,132(1):70-92
The changes in macrofauna and microfauna, before, during and after the latest Cenomanian global Oceanic Anoxic Event (OAE2), from the Eastern Desert of Egypt are documented, along with an inferred paleoenvironment. The age of the studied OAE2 interval is constrained by the last occurrence of the marker calcareous nannofossils species Axopodorhabdus albianus along with the previously identified positive δ13C excursion from the coeval ammonite Vascoceras cauvini Zone (= Neocardioceras juddii Zone), enabling correlation with the peak ‘b’ of the OAE2. Based on the studied microfaunal assemblages, a warm shallow restricted lagoonal environment with mesotrophic conditions and strong seasonality is inferred. The presence of a rare ammonite (and ostracods) attest to the intermittent introduction of marine waters within this inner ramp setting. In terms of sequence stratigraphy, two 3rd order depositional sequences are recorded. The top surface of the first depositional sequence, at the sequence boundary, SB Ce 5 (the start of the OAE2), is marked by an abrupt faunal change with reduced abundances of the macrofaunal elements. This is in tune with other Egyptian records of relatively smaller loss (10 %) at the Cenomanian-Turonian boundary, as compared to much higher numbers (53–79% of species), globally. This faunal (biotic bottleneck) and lithological change (from siliciclastic-dominated deposits to a largely carbonate-dominated one) at the SB Ce 5 is attributed as a response to the latest Cenomanian drowning (the highest sea-level during the Phanerozoic), that also resulted in the formation of carbonate platform. 相似文献
54.
Ibrahim Elkhedr Mogren Saad Qaysi Saleh Abdelrahman Kamal Ghrefat Habes Zaidi Faisal Hakami Ahmed 《Natural Hazards》2021,108(3):2613-2628
Natural Hazards - The main objective of this study is to detect the subsurface extension of salt diapirs and structural deformations in the city of Jazan and its suburbs using gravity data. Salt... 相似文献
55.
Acta Geochimica - Mineralogical and geochemical characteristics of stream sediments collected from 30 stations in the Dahab-Wadi Kid area (southeastern Sinai, Egypt) are presented. The studied... 相似文献
56.
The garnet muscovite granitic pegmatite of Um Solimate, in southern Egypt, represents a promising asset for strategic and economic metals, especially Bi–Ni–Ag–Nb–Ta as well as U and Th. The ore bodies occur as large masses, pockets and/or veins of very coarse-grained pegmatites, which consist mainly of K-feldspar, quartz and albite with subordinate muscovite, garnet, and biotite. Radiometric data revealed that eU- and eTh-contents of the pegmatites reach up to 39 ppm and 82 ppm, respectively. The studied pegmatites are enriched in primary U and Th minerals (uraninite, coffinite, thorianite and uranothorite) as well as Hf-rich zircon and monazite, which give rise to anomalous radioactive zones. Niobium-tantalium-bearing minerals (i.e. ferrocolumbite, microlite and uranopyrochlore), xenotime, barite, galena, fluorite, and apatite are ubiquitous, and, consequently, the studied pegmatites belong tothe Niobium–Yttrium–Fluorine-type (NYF) family. The noble metal mineralization includes argentite (Ag2S), native Ni and Bi as well as bismite and bismoclite. In addition, beryl and tourmaline are observed in pegmatites near the contact with metasediments and ultramafic bodies. The observed compositional variations of Ta/(Ta+Nb) and Mn/(Mn+Fe) ratios in columbite (0.08–0.45 and 0.11–0.57, respectively) and Hf contents in zircon (3.54–6.46 wt%) may reflectan extreme degree of magmatic fractionation leading to formation of the pegmatite orebody. 相似文献
57.
Sidali Kourdali Nabila Bounakous Abdellah Meknachi Bilal Zenati Ahmed Inal 《Ocean Science Journal》2020,55(4):521-536
Ocean Science Journal - Biological monitoring has become one of the most widely used approaches in aquatic monitoring. As a result, the effect of the xenobiotics entrained by the organic and... 相似文献
58.
Ali Moamen Abdelhady A. Abdelmaksoud Ahmed Darwish M. Essa M. A. 《Natural Resources Research》2020,29(2):1259-1281
Natural Resources Research - The Albian/Cenomanian reservoir is one of the two main reservoirs composing the petroleum system in the Komombo Basin. However, these reservoirs have not previously... 相似文献
59.
Ali Moamen Abdelmaksoud Ahmed Essa M. A. Abdelhady A. Darwish M. 《Natural Resources Research》2020,29(4):2575-2597
Natural Resources Research - Two main reservoirs are producing in Komombo Basin: the first one belongs to the C Member of the Six Hills Formation, and the second belongs to the Albian/Cenomanian... 相似文献
60.
Alameer Zakaria Elaziz Mohamed Abd Ewees Ahmed A. Ye Haiwang Jianhua Zhang 《Natural Resources Research》2019,28(4):1385-1401
Natural Resources Research - An accurate forecasting model for the price volatility of minerals plays a vital role in future investments and decisions for mining projects and related companies. In... 相似文献