Leaching of Lisan Marl and its consequences on the engineering behavior of dikes,studied by finite elements modeling     

Ziad Mahmoud Mansour  Mohd Raihan Taha  Zamri Chik  Anuar Kasa 《Environmental Earth Sciences》2009,59(4):891-900

Leaching of Lisan Marl, Dead Sea, Jordan increased the soil compressibility and cohesion intercept. Back analysis using the Plaxis finite element code was successfully implemented. The Finite element modeling of dike construction showed a significant increase of total settlement and negligible effect on the strength as calculated by the φ/c reduction method. The height of dikes to be constructed on Lisan Marl as foundation material, should be optimized to account for the effect of soluble salts leaching. For this to take place, an accurate calculation of settlement is crucial.  相似文献   

Saturation states of carbonate minerals in a freshwater-seawater mixing zone of small tropical island’s aquifer     

Ahmad Zaharin Aris  Sarva Mangala Praveena  Mohd Harun Abdullah 《中国地球化学学报》2010,29(3):278-286

Groundwater is a crucial resource on the Manukan Island as it is the only source of freshwater available on the island. The aquifer has deteriorated to a high degree, during the last decade. Nine domestic wells were sam-pled from March 2006 to January 2007 to probe the hydrochemical components that influence the water quality. Geochemical data on dissolved major constituents in groundwater samples from the Manukan Island revealed the main processes responsible for their geochemical evolution. The results using statistical analyses, graphical method and numerical model output (PHREEQC) showed that the groundwater was chemically highly enriched in Na and Cl, indicative of seawater intrusion into the aquifer as also supported from the Na-Cl signature on the Piper diagram. From the PHREEQC simulation model, calcite, dolomite and aragonite solubility showed positive values of the saturation indices (SI), indicating supersaturation which led to mineral precipitation condition of water by these min-erals.  相似文献   

The stellar halo of the Galaxy     

Amina Helmi 《Astronomy and Astrophysics Review》2008,15(3):145-188

Stellar halos may hold some of the best preserved fossils of the formation history of galaxies. They are a natural product of the merging processes that probably take place during the assembly of a galaxy, and hence may well be the most ubiquitous component of galaxies, independently of their Hubble type. This review focuses on our current understanding of the spatial structure, the kinematics and chemistry of halo stars in the Milky Way. In recent years, we have experienced a change in paradigm thanks to the discovery of large amounts of substructure, especially in the outer halo. I discuss the implications of the currently available observational constraints and fold them into several possible formation scenarios. Unraveling the formation of the Galactic halo will be possible in the near future through a combination of large wide field photometric and spectroscopic surveys, and especially in the era of Gaia.  相似文献   

Bianchi type-V perfect fluid space-time models in general relativity     

C. P. Singh  Shri Ram  Mohd. Zeyauddin 《Astrophysics and Space Science》2008,315(1-4):181-189

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Is the sky falling? Searching for stellar streams in the local Milky Way disc in the CORAVEL and RAVE surveys     

G. M. Seabroke  G. Gilmore  A. Siebert  O. Bienaymé  J. Binney  J. Bland-Hawthorn  R. Campbell  K. C. Freeman  B. Gibson  E. K. Grebel  A. Helmi  U. Munari  J. F. Navarro  Q. A. Parker  A. Siviero  M. Steinmetz  F. G. Watson  R. F. G. Wyse  T. Zwitter  J. Peñarrubia  M. C. Smith  M. Williams 《Monthly notices of the Royal Astronomical Society》2008,384(1):11-32

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Watershed prioritization using morphometric and land use/land cover parameters: A remote sensing and GIS based approach   总被引：4，自引：0，他引：4  

Akram Javed  Mohd Yousuf Khanday  Subah Rais 《Journal of the Geological Society of India》2011,78(1):63-75

Jaggar watershed is a constituent of the Gambhir river basin, in eastern Rajasthan and covers an area of 352.82 km², representing arid climate. The drainage network is dendritic to sub-dendritic pattern however parallel to sub-parallel has also developed locally. The Jaggar watershed has been divided into fourteen sub-watersheds, designated as SW1 to SW14, for prioritization purpose. The prioritization of the sub-watersheds has been done on the basis of morphometric analysis and land use/land cover categories. Various morphometric parameters (linear and shape) have been determined for each sub-watershed and assigned rank on the basis of value/relationship with erodibility so as to arrive at a compound value for final ranking of the sub-watersheds. Land use/land cover mapping has been carried out using IRS LISS III data of 1998. Based on morphometric and land use/land cover analysis and their ranks, the subwatersheds have been classified into four categories as very high, high, medium and low in terms of priority for conservation and management of natural resources. The prioritization results based on morphometry reveal that only SW7 and SW10 fall under very high priority, whereas SW6, SW11 and SW13 fall under very high priority on the basis of land use/land cover analysis. However on the integration of morphometry and land use/land cover only SW14 show common priority whereas rest have little or no correlation.  相似文献   

Aquifer hydraulic conductivity estimation from surface geoelectrical measurements for Krauthausen test site, Germany   总被引：2，自引：0，他引：2  

Sri Niwas  B. Tezkan  Mohd Israil 《Hydrogeology Journal》2011,19(2):307-315

The physical explanation is presented for two types of theoretical equations which encompass a direct and an inverse relationship between the hydraulic conductivity and electrical resistivity of an aquifer. Using the theory of direct current (DC) resistivity prospecting, it is shown that a direct relation exists if the bulk of the current flow is in the vertical direction, whereas the inverse relation exists if the current is in the horizontal direction. Consequently, the relation in question is direct in the case of a relatively conducting basement and inverse in the case of a comparatively resistive basement. Then, the aquifer hydraulic conductivity for the hydrogeologically well-studied area of Krauthausen in Germany is estimated by two different techniques using surface geoelectrical data. The estimated values are compared with those conventionally determined by a pump test experiment and it can be concluded that the estimation is better whenever geoelectrical data are used.  相似文献   

Compression of remote sensing data using second-generation wavelets: a review     

Ladan Ebadi  Helmi Z. M. Shafri 《Environmental Earth Sciences》2014,71(3):1379-1387

Wavelet-based methods have been widely used for compression of remotely sensed images and data. Recently, second generation of wavelets which is based on a method called lifting has proven to be more effective than traditional wavelets as it provides lossless compression, lowers the memory usage, and is computationally faster. This study explores the literature related to applying second-generation wavelets for the compression of remote sensing data. Nevertheless, in order to compare the results of two wavelet types, some applications of traditional wavelets are also presented.  相似文献   

Composition of selected heavy metals in road dust from Kuala Lumpur city centre   总被引：1，自引：1，他引：0  

Nur Mun’im Mohd Han  Mohd Talib Latif  Murnira Othman  Doreena Dominick  Noorlin Mohamad  Hafizan Juahir  Norhayati Mohd Tahir 《Environmental Earth Sciences》2014,72(3):849-859

This study was carried out in order to determine the concentration of heavy metals, e.g., lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), nickel (Ni) and chromium (Cr) in road dust in Kuala Lumpur’s city centre. Samples were collected from four sampling locations, each of which had four sampling points and three replications. Heavy metals from different fractions of particles separated by different diameter sizes: d < 63 μm (Fraction A), 63 < d < 125 μm (Fraction B) and 125 < d < 250 μm (Fraction C) were analyzed using inductively coupled plasma mass spectrometry. The results from this study showed that concentration of heavy metals was dominated by the smallest particle size: <63 μm and that Fe was the most abundant heavy metal overall, followed by Cu > Mn > Zn > Pb > Ni > Cr > Cd. The fact that Cd had the highest enrichment factor value (EF) for all particle sizes indicates that anthropogenic activities contributed to the presence of this metal. There was also a higher EF value for heavy metals in small particle (Fraction A), compared to Fraction B and C, which suggests that fine particles were being produced through anthropogenic activities. Cluster analysis and principal component analysis demonstrated the likelihood of the heavy metals detected in the road dust, originating from road traffic and industrial activities.  相似文献   

Particle tracking analysis of river–aquifer interaction via bank infiltration techniques     

Mohd Khairul Nizar Shamsuddin  Saim Suratman  Mohamad Pauzi Zakaria  Ahmad Zaharin Aris  Wan Nor Azmin Sulaiman 《Environmental Earth Sciences》2014,72(8):3129-3142

Induced bank infiltration (BI) is commonly implemented in other countries, but remains new and unexplored in Malaysia. Increasing river pollution could affect drinking water resources. Given the threat of pollution to raw water sources, applying induced BI to sustain water management is essential. This paper presents a case study of the BI method, which evaluates the effects of groundwater pumping and BI operation on the installation of wells as well as determines the effect of pumping rate on flow paths, travel time, the size of the pumping and capture zone delineation, and groundwater mixing in a pumping well in Jenderam Hilir, Malaysia. The proposed method performs infiltration safely and achieves the ideal pumping rate. Numerical modeling packages, MODFLOW and MODPATH (particle tracking) were used. Results indicate that the migration of river water into the aquifer is generally slow and depends on the pumping rate and distance from well to the river. Most water arrives at the well by the end of a pumping period of 1–5 days at 3,072 m³/day for test wells DW1 and DW2, and during simultaneous pumping for DW2 and PW1 for a well located 36 and 18 m, respectively, from the river. During the 9.7-day pumping period, 33 % of the water pumped from the DW1 well was river water, and 38 % from DW2 throughout 4.6 days was river water. The models provide necessary information for water operators in the design and construction of pumping and sampling schedules of BI practices.  相似文献