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61.
Mohamed Adel Sharaf 《Astrophysics and Space Science》1984,104(2):267-284
In this paper of the series, elliptic expansions in terms of the sectorial variables
j
(i)
introduced recently in Paper IV (Sharaf, 1982) to regularize highly oscillating perturbations force of some orbital systems will be established analytically and computationally for the fifth and sixth categories. For each of the elliptic expansions belonging to a category, literal analytical expressions for the coefficients of its trigonometric series representation are established. Moreover, some recurrence formulae satisfied by these coefficients are also established to facilitate their computations; numerical results are included to provide test examples for constructing computational algorithms. 相似文献
62.
63.
Soil erosion prediction based on land cover dynamics at the Semenyih watershed in Malaysia using LTM and USLE models 总被引:1,自引:0,他引:1
This study attempts to identify and forecast future land cover (LC) by using the Land Transformation Model (LTM), which considers pixel changes in the past and makes predictions using influential spatial features. LTM applies the Artificial Neural Networks algorithm) in conducting the analysis. In line with these objectives, two satellite images (Spot 5 acquired in 2004 and 2010) were classified using the Maximum Likelihood method for the change detection analysis. Consequently, LC maps from 2004 to 2010 with six classes (forest, agriculture, oil palm cultivations, open area, urban, and water bodies) were generated from the test area. A prediction was made on the actual soil erosion and the soil erosion rate using the Universal Soil Loss Equation (USLE) combined with remote sensing and GIS in the Semenyih watershed for 2004 and 2010 and projected to 2016. Actual and potential soil erosion maps from 2004 to 2010 and projected to 2016 were eventually generated. The results of the LC change detections indicated that three major changes were predicted from 2004 to 2016 (a period of 12 years): (1) forest cover and open area significantly decreased at rates of almost 30 and 8 km2, respectively; (2) cultivated land and oil palm have shown an increment in sizes at rates of 25.02 and 5.77 km2, respectively; and, (3) settlement and Urbanization has intensified also by almost 5 km2. Soil erosion risk analysis results also showed that the Semenyih basin exhibited an average annual soil erosion between 143.35 ton ha?1 year?1 in 2004 and 151 in 2010, followed by the expected 162.24 ton ha?1 year?1. These results indicated that Semenyih is prone to water erosion by 2016. The wide range of erosion classes were estimated at a very low level (0–1 t/ha/year) and mainly located on steep lands and forest areas. This study has shown that using both LTM and USLE in combination with remote sensing and GIS is a suitable method for forecasting LC and accurately measuring the amount of soil losses in the future. 相似文献
64.
The groundwater of the Korba plain represents major water resources in Tunisia. The Plio‐Quaternary unconfined aquifer of the Cap‐Bon (north‐east Tunisia) is subject to the intensive agricultural activities and high groundwater pumping rates due to the increasing of the groundwater extraction. The degradation of the groundwater quality is characterized by the salinization phenomena. Groundwater were sampled and analysed for physic‐chemical parameters: Ca2+, Mg2+, Na+, K+, Cl‐, SO42‐, HCO3‐, NO3‐, pH, electrical conductivity (EC), and the temperature (T°). The hydrochemical analysis is coupled with the calculation of the saturation indexes (SI gypsum, SI halite, SI calcite and SI dolomite), ionic derivation and with the ion correlations compared to chloride concentrations: Na+/ Cl‐, Ca2+/ Cl‐ and Mg2+/ Cl‐ ratios. Seawater fractions in the groundwater were calculated using the chloride concentration. Those processes can be used as indicators of seawater intrusion progression. EC methods were also conducted to obtain new informations on the spatial scales and dynamics of the fresh water–seawater interface of coastal groundwater exchange. The mixing zone between freshwater and saltwater was clearly observed from the EC profile in the investigated area where a strong increase in EC with depth was observed, corresponding to the freshwater and saltwater interface. Results of hydrochemical study revealed the presence of direct cation exchange linked to seawater intrusion and dissolution processes associated with cations exchange. These results, together with EC investigation, indicated that the groundwater is affected by seawater intrusion and is still major actor as a source of salinization of the groundwater in Korba coastal plain. Further isotopic and hydrological investigations will be necessary to identify and more understood the underlying mechanisms. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
65.
Local groundwater governance in Yemen: building on traditions and enabling communities to craft new rules 总被引:1,自引:1,他引:0
Taha Taher Bryan Bruns Omar Bamaga Adel Al-Weshali Frank van Steenbergen 《Hydrogeology Journal》2012,20(6):1177-1188
Local groundwater management in Yemen and the means by which stakeholders can work together to improve water governance are discussed. In the last few decades the discourse on groundwater management in Yemen has increasingly been cast in terms of crisis, triggered by rapidly declining water tables around cities and in the main agricultural areas. However, in some places in Yemen, communities have responded by implementing local rules that have reduced conflict and provided more reliable and equitable access to water. This trend towards development of local groundwater governance is described, and could make a major contribution in realizing the goals of national water-sector policies and strategies. Twenty-four cases have been identified from different parts of the country and five cases are presented in detail. The article discusses how the process of local management could be nurtured and how it could contribute to rebalancing water use in several parts of Yemen. 相似文献
66.
We expand the principal part of the planetary disturbing function, by Smart's method, using Taylor's theorem. In our expansion we neglect terms of degree higher than the fourth in the eccentricities and tangents of the inclinations.Now at the JPL Pasadena, California. 相似文献
67.
The response surface methodology involving the five‐level central composite design (CCD) was employed to model and optimize the Cr(VI) immobilization process in a Cr‐spiked soil using starch‐stabilized zerovalent iron nanoparticles (ZVIn). ZVIn were synthesized via a borohydride reduction method and characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). All Cr(VI) immobilization experiments were conducted in a batch system. The variables for the CCD optimization were the ZVIn dosage (% w/w), reaction time (min), and initial Cr(VI) concentration in soil (mg/kg). The predicted response values by the second‐order polynomial model were found to be in good agreement with experimental values (R2 = 0.968 and adj‐R2 = 0.940). The optimization result showed that the Cr(VI) immobilization efficiency presented the maximal result (90.63%) at the following optimal conditions: ZVIn dosage of 1.5% w/w, reaction time of 60 min, and an initial Cr(VI) concentration of 400 mg/kg. 相似文献
68.
Petrophysical characteristics of the late Miocene Wakar Formation of Port Fouad Marine Field have been evaluated through the analysis of well-logging records of nine exploratory and development wells, distributed in the northeastern offshore area of the Nile Delta. These records have been analyzed through utilizing the ELAN Plus petrophysics software in order to identify the lithological constituents and fluid saturation parameters. The gas potentialities of the studied formation have been evaluated through number of isoparameteric maps. The litho-saturation analysis indicates that the Wakar Formation in the studied wells is mainly gas-bearing with some water-bearing sand levels. The analytical formation evaluation reveals that the lithological facies consists mainly of sandstone, shale, and siltstone. The disseminated shale is mainly of dispersed type and some of laminated habitat. It also points to the dominance of the intergranular porosity. The isoparametric maps of the petrophysical parameters show that the level S1 of Wakar Formation is the main reservoir. 相似文献
69.
Adel Javdani Naeini A. J. Choobbasti M. Saadati 《Arabian Journal of Geosciences》2013,6(11):4487-4497
The significance of liquefaction-related damage to pile foundations has been clearly demonstrated by the major earthquakes occurring during past years. The current project investigates the seismic behaviour of a single pile in the three-layered soil of the Babol City centre site (located in Babol City, Mazandaran Province, Iran). The site soil consists of sandy and clayey soils modelled based on the data collected from drilled boreholes. Numerical analysis was performed using Flac2D finite difference program. Three different natural ground motion records are considered, and the influence of each earthquake on the bending moment and lateral displacement of the simulated pile is investigated. In addition, the effect of vertical surcharge on the settlement of the pile during the earthquakes is investigated. Results illustrate that the maximum bending moment has occurred on the interface of liquefiable and non-liquefiable soil layers. 相似文献
70.
Adel Zein Bishta 《Arabian Journal of Geosciences》2013,6(9):3513-3526
Wadi Baba–Wadi Shalal area locates in the westcentral part of Sinai, Egypt. It is covered by a Precambrian basement rocks comprise the northern part of the Precambrian Arabo-Nubian crystalline massive. The lithologic and structural setting of the investigated area was interpreted from the digital Landsat-7 Enhanced Thematic Mapper Plus (ETM+) data. The structural lineament analyses for the lithologic units and their relationships to the high-radioactivity zones (HRZ) and the characterizations of HRZ of the study area are the main tasks of this article. Extraction algorithm was applied using Geomatica PCI package under the user defined parameters. The extracted structural lineaments have been evaluated and chicked using the visual interpretation and published works. The short-wave infrared spectral ETM+ band-7 was selected as an optimum data for automatic lineaments extraction since it scored the highest lineament frequency (1856) compared to the other visible and near infrared bands. The aeroradiometric color raster total count equivalent thorium (eTh) and equivalent uranium (eU) maps were used to delineate the highest radioactivity zones of the study area. A selective image processing technique (SIPT) is a new approach in Geomatica (9.1), which gives rise to valuable results in this work. The SIPT was carried out for the subset of the ETM+ data of the highest radioactivity zones. The spatial distribution of the structural lineament pattern maps for some low-radioactivity zones (LRZ) and for the highest radioactivity zones of the study area are prepared with their frequency rose diagrams. The NE–SW trend is the predominant structural lineaments trend in the investigated area. The NE–SW to the ENE–WSW directions are the predominant structural lineament trends in both the LRZ and the HRZ. These high-radioactivity zones of the investigated area are characterized by high lineaments density and lineaments-intersection density, restricted to Um Bogma Formation and younger granitic rocks and are not controlled by structural lineament trends. 相似文献