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761.
We constructed an analytical theory of satellite motion up to the third order relative to the oblateness parameter of the Earth (J 2). Equations of secular variations was developed for the first three orbital elements (a, e, i) of an artificial satellite. The secular variations are solved in a closed form. 相似文献
762.
Geotectonics - Poly-deformed late-Proterozoic metamorphic domains covering Um Ashira area at the western segment of Wadi Allaqi shear zone, South Eastern Desert of Egypt, show evidences of inverted... 相似文献
763.
Abdlrahem Maged A. El Naggar M. Hesham 《Geotechnical and Geological Engineering》2021,39(5):3669-3688
Geotechnical and Geological Engineering - Hollow bar micropiles (HBMP) have been popular for some time due to their fast installation and efficient load transfer mechanism. In the construction of... 相似文献
764.
The demand on green and clean energy is increasing all over the world. This urge us to try to reduce the obstacles in this field. One of the main obstacles is the high cost of offshore foundation system of wind turbines. A novel offshore hybrid foundation system is proposed for large offshore wind turbines to try to reduce the construction cost. This new system consists of circular precast concrete plate connected on site (i.e. offshore) to a steel monopole that is smaller than the usual pile size used. Parametric study for different foundations systems including monopiles had been done. The displacements at different locations of the foundation and the rotation at the pile head were analyzed and evaluated using a 3D nonlinear finite element model under field-like loading conditions considering different foundation configurations. This work paves the way for the development of design guidelines for this novel foundation system in offshore wind turbine applications. 相似文献
765.
Pouclet André El Hadi Hassan Álvaro J. Javier Bardintzeff Jacques-Marie Benharref Mohammed Fekkak Abdelilah 《International Journal of Earth Sciences》2018,107(6):2101-2123
International Journal of Earth Sciences - Volcanic activities related to the opening of a Cambrian rift in Morocco were widespread from the Fortunian to the Cambrian Epoch 3. Numerous data are... 相似文献
766.
Paola Manzotti Daniela Rubatto Michele Zucali Afifé El Korh Bénédicte Cenki-Tok Michel Ballèvre Martin Engi 《Swiss Journal of Geoscience》2018,111(1-2):79-97
In the Dent Blanche Tectonic System, the Mont Morion biotite-bearing granite is a km-scale intrusion preserved in a low-strain volume. Zircon saturation thermometry suggests that it crystallised from a melt that reached about 800 °C. U–Pb zircon and allanite geochronology indicates crystallization of the magma in the Permian (290 ± 3 Ma; 280 ± 8 Ma, respectively). Migmatitic biotite-gneiss and amphibolite are found as xenoliths within the Mont Morion granite and constitute its country-rocks. In two samples of migmatitic biotite-gneiss zircon has metamorphic overgrowths that yield U–Pb ages of 285 ± 3 Ma and 281 ± 4 Ma, and are thus contemporaneous with the intrusion of the granite. The Mont Morion granite with its country-rocks of migmatitic biotite-bearing gneiss and amphibolite was thus emplaced at middle crustal levels while amphibolite facies metamorphism affected its country rocks. The magmatic and metamorphic record in the Mont Morion area reflects the high-temperature regime and lithospheric thinning of the Adriatic continental margin during Permian. 相似文献
767.
Meriem Snineh Nour-Eddine Laftouhi Khalid Mehdi Abdenbi El Mandour Abdessamad Hejjaj Laila Mandi 《Environmental Earth Sciences》2018,77(3):102
The Bleida fractured aquifer is not well studied in terms of water resources as previous geophysical investigations in this area were undertaken for mining purposes. This study utilized magnetic resonance sounding surveys in order to define the distribution of water resources in the region of Bleida and to locate areas favorable for the drilling and construction of productive hydraulic boreholes. For this purpose, eight magnetic resonance sounding surveys were conducted in two sites at the intersection of faults in basement rocks. The results of these surveys indicated that there were two distinct levels of saturation in fractured rock that decreased with depth. 相似文献
768.
Mohd S. Abu Jabal Ismail Abustan Mohd Remy Rozaimy Hussam El Najar 《Environmental Earth Sciences》2018,77(4):155
The environmental isotopes such as deuterium and oxygen-18 and the deuterium excess values have been used to assess groundwater recharge sources and their dynamics in Khan Younis City in the Gaza Strip in Palestine. Three isotopic lines for the relationship between δ2H and δ18O were used in the assessment. These lines are the global meteoric water line, the local meteoric water line and the groundwater evaporation line. The δ2H, δ18O and D-excess values indicate that deuterium and oxygen-18 isotopes originated in the groundwater from groundwater mixing with rainfall and other water sources; the groundwater in the area recharged from rainfall from a distant source that came from the Mediterranean Sea and from other sources such as wastewater, irrigation return flow and saline water. 相似文献
769.
Comparative approach of three popular intrinsic vulnerability methods: case of the Beni Amir groundwater (Morocco) 总被引:1,自引:0,他引:1
Najat Knouz Abdelghani Boudhar El Mostafa Bachaoui Charkaoui Saadi 《Arabian Journal of Geosciences》2018,11(11):281
The study of the intrinsic vulnerability of groundwater resources to pollution is an effective tool to control their quality degradation and contribute to their protection. It is used to delimit the vulnerable zones which do not withstand a large flow of pollutants introduced from the soil surface. Three methods of assessing the intrinsic vulnerability of groundwater: DRASTIC (Depth to water table, Recharge, Aquifer, Soil type, Topography, Impact of zone vadose, Hydraulic conductivity), DRSTI, and GOD (Groundwater occurrence, Overall aquifer class and Depth of water table) coupled with a geographic information system (GIS) are applied to the groundwater of Beni Amir, and they are compared in order to adopt the method which better characterizes the vulnerability of the aquifer to pollution. The validation of this application was made by measurements of the nitrate levels in the aquifer. Because the pollution of groundwater, in this plain, is a direct consequence of agricultural activities characterized by an intensive fertilizer application. The results clearly show that the rate of the coincidence, between the measured nitrate concentrations and the different classes of vulnerability of three methods, is 81.81, 54.54, 72.72, and 27.27%, respectively, for methods DRASTIC (classification of Engel et al. (Int Assoc Hydrol Sci Publi 235:521–526, 1996)), DRASTIC (classifications of Aller et al. (1987)), DRSTI, and GOD. Of this rate of coincidences, the DRASTIC method, with the classification of Engel et al. (Int Assoc Hydrol Sci Publi 235:521–526, 1996), allows a finer assessment and turns out the most representative of the study area. 相似文献
770.
El Osta Maged 《Arabian Journal of Geosciences》2018,11(20):642
The Paris–Abu Bayan area located along the Darb El Arbaein road is involved in the New Valley Project in the Egyptian Western Desert (EWD) as part of ongoing efforts since the 1960s. In this dryland area, groundwater stored in the Nubian Sandstone Aquifer System (NSAS) serves as the only water resource for a number of different uses. A major concern is the significant groundwater withdrawals from 74 pumped wells since the beginning of agricultural activities in 2000. The recent rapid expansion of agricultural activity and the lack of sufficient groundwater recharge as a result of unplanned groundwater development have led to severe stress on the aquifer. Field measurements have shown a rapid decline in groundwater levels, creating a crisis situation for this sole source of water in the area. In this study, mathematical modeling of the groundwater system (single aquifer layer) of the Paris–Abu Bayan reclaimed area was implemented using MODFLOW to devise a new strategy for the sustainable use of groundwater, by applying a number of scenarios in a finite-difference program. The conceptual model and calibration were developed by generating and studying the hydrogeological records, NSA parameters, production wells, and water level measurements for 2005 and 2012. Three management scenarios were applied on the calibrated model to display the present and future stresses on this aquifer over a 30-year period (2012–2042). The results clearly show a high decline in the heads of the NSA, by about 13.8 m, due to the continuous withdrawal of water (first scenario: present conditions, 102,473 m3/day). In the second scenario, the water level is expected to decrease significantly, by about 16 m, in most of the reclamation area by increasing the pumping rates by about 25% (over-pumping) to meet the continuous need for more cultivation land in the area. To reduce the large decline in water levels, the third plan tests the aquifer after reducing the water withdrawal by approximately 25%, applying modern irrigation systems, and suggesting two new reclaimed areas in the northeastern and northwestern parts (areas 1 and 2), with 20 new wells, at 500 m3/day/well. The results in this case show that groundwater levels are slightly decreased, by about 9.5 m, while many wells (especially the new wells in the northern part) show a slight decrease in groundwater levels (0.8 m). The results comparison shows that the groundwater level in the modeled area is lowered by 0.3 m/year with an increase in the number of wells to 94 and increased cultivation area by about 18% (third scenario), versus 0.45 m/year and 0.60 m/year recorded for the first and second scenarios, respectively. Therefore, based on the results, the third scenario is recommended as a new strategy for improving groundwater resource sustainability in the region. 相似文献