Contribution of the Root to Slope Stability     

Abdolhossein Khalilnejad  Faisal Hj. Ali  Normaniza Osman 《Geotechnical and Geological Engineering》2012,30(2):277-288

Land sliding is a geotechnical event that includes a wide range of ground movements such as rockfalls, deep failure of slopes and shallow debris flows, and it can cause various problems in varied civil fields such as roads and dams. Since most conventional methods are neither inexpensive nor applicable everywhere, attention has nowadays been drawn to soil bioengineering using vegetation as the environment-friendly method for slope stabilization. Soil bioengineering or using vegetation in civil engineering design is mostly applicable to shallow slope stabilization projects characterized by unstable slopes with surface movement. Vegetation has both a silent effect on soil improvement to predict the landslide and a mechanical role to increase shear and pulling-out stress on the soil. During the last decade, many researches have been carried out to clarify the effect of vegetation on slope stability, but many questions still remain to be answered.  相似文献   

The Sha’it–Nugrus shear zone separating Central and South Eastern Deserts,Egypt: A post-arc collision low-angle normal ductile shear zone     

A. Fowler  A.F. Osman 《Journal of African Earth Sciences》2009,53(1-2):16-32

The northerly dipping Sha’it–Nugrus shear zone (SNSZ) is the boundary separating the Central Eastern Desert from the South Eastern Desert of Egypt. The hangingwall of this shear zone is composed of low-grade metavolcanics and ophiolitic nappes of the Central Eastern Desert, while the footwall consists of South Eastern Desert high-grade metapsammitic gneisses (Migif-Hafafit gneissic complex). The SNSZ is about 700 m thick and represents the shear foliated lower parts of the hangingwall and upper parts of the footwall. A significant part of the SNSZ has been truncated by a later normal fault along Wadi Sha’it, however the SNSZ is well-preserved along Wadi Nugrus. Features of the SNSZ include shear-related schistosity (termed Ss), mylonite zones, sheared syn-kinematic granitoid intrusions, diverse metasomatism and metamorphic effects (higher T overprinting of hangingwall lithologies and retrogression of footwall lithologies). Shear-sense indicators clearly show top-to-N or NW displacement sense. SNSZ structures overprint arc collision related nappe structures (～680 Ma) and are therefore post-arc collision. SNSZ syn-kinematic intrusives have been dated at ～600 Ma. The SNSZ is deformed (regionally and locally folded and thrust dissected) during later NE–SW compressive tectonism. The SNSZ had an originally approximately E–W strike, low-angle N-dip and a normal shear sense, making this an example of a low-angle normal ductile shear (LANF) or detachment fault. The steep NE dip of Ss foliations and low-pitching slip lineations along Wadi Nugrus are due to NW–SE folding of the SNSZ, and do not indicate a sinistral strike-slip shear zone. The normal shear sense activity is responsible for juxtaposing the low-grade Central Eastern Desert lithologies against South Eastern Desert gneisses. A displacement of 15–30 km is estimated on the SNSZ, which is comparable to LANF displacements in the Basin and Range province of the western USA. Frictional resistance along this shear was probably reduced by high magmatic fluid pressure and hydrothermal fluid pressure. The vastness and diversity of the hydrothermal activity along this shear zone is a characteristic of other LANFs in the Eastern Desert, e.g. at Gabal El-Sibai, and may be Gabal Meatiq. The SNSZ formed during the Neoproterozoic extensional tectonic phase of Eastern Desert that began ～600 Ma, and followed arc collision and NW-ward ejection of nappes.  相似文献   

Purification of diatomite powder by acid leaching for use in fabrication of porous ceramics   总被引：1，自引：0，他引：1  

Osman an  Remzi Gren  Cem zgür 《International Journal of Mineral Processing》2009,93(1):6-10

This study presents an investigation of the purification of a raw diatomite by acid leaching conducted in hot solution (75 °C and 5 M HCl) for long periods up to 240 h, evaluates the use of these purified powders in the fabrication of porous materials, and examines their porosities. The treatment for 1 h increased the specific surface area of diatomite from 189 m²/g to 222 m²/g, but the SiO₂ content of 78.66% was still low. Material leached for a relatively short time shows an amorphous phase with quartz and plagioclase phases and the plagioclase is removable at longer leaching times during which no disruptive effect on the fine microscopic pores of the particles was observed. Thus, the diatomite based powders have potential use in the fabrication of porous coating as a membrane-separating layer: sintering at a relatively high temperature (1300 °C) still showed a significantly high apparent porosity of 48%.  相似文献   

Earth Science Education in Sudan     

Osman M. Abdullatif  Abdalla G. Farwa 《Journal of African Earth Sciences》1999,28(4):825-835

This paper describes Earth Science Education in Sudan, with particular emphasis on the University of Khartoum. The first geological department in Sudan was founded in 1958 in the University of Khartoum. In the 1980s, six more geological departments have been added in the newer universities. The types of courses offered include Diploma, B.Sc. (General), B.Sc. (Honours), M.Sc. and Ph.D. The Geology programmes are strongly supported by field work training and mapping. Final-year students follow specialised training in one of the following topics: hydrogeology, geophysics, economic geology, sedimentology and engineering geology. A graduation report, written in the final year, represents 30–40% of the total marks. The final assessment and grading are decided with the help of internal and external examiners.Entry into the Geology programmes is based on merit and performance. The number of students who graduate with Honours and become geologists is between 20% to 40% of the initial intake at the beginning of the second year. Employment opportunities are limited and are found mainly in the Government's geological offices, the universities and research centres, and private companies. The Department of Geology at the University of Khartoum has long-standing internal and external links with outside partners. This has been manifested in the training of staff members, the donation of teaching materials and laboratory facilities. The chief problems currently facing Earth Science Education in Sudan are underfunding, poor equipment, laboratory facilities and logistics. Other problems include a shortage of staff, absence of research, lack of supervision and emigration of staff members.Urgent measures are needed to assess and evaluate the status of Earth Science Education in terms of objectives, needs and difficulties encountered. Earth Science Education is expected to contribute significantly to the exploitation of mineral resources and socio-economic development in the Sudan.  相似文献   

Rate of seawater intrusion estimated by geophysical methods in an arid area: Al Khabourah, Oman     

Osman A. E. Abdalla  Mubarik Ali  Khalifa Al-Higgi  Hilal Al-Zidi  Issa El-Hussain  Said Al-Hinai 《Hydrogeology Journal》2010,18(6):1437-1445

Seawater intrusion and its spreading rate are the challenging problems in over-pumped coastal aquifers of arid zones like the Batinah region of Oman. The study delineates the saline plume, identifies saline/freshwater zones, and estimates the migration rate of the plume in the Al Khabourah area of the Batinah coast. Time domain electromagnetic surveys, aided by vertical electrical sounding surveys, and seismic refraction methods have defined the locus of the saline/freshwater interface in the area. The current (2007) interface position, when compared with that determined during 2002, indicates a prominent recession in the saline plume and suggests an average annual recession rate of 120 m. This recession may be attributed mainly to the recharging dam of Wadi Al Hawasinah, constructed in 1995, and the enforcement of new water resources legislation. This study reveals the shielding role of the recharging dam to counter advancing saline intrusion.  相似文献   

Cyanide from gold mining and its effect on groundwater in arid areas,Yanqul mine of Oman   总被引：2，自引：1，他引：1  

Osman A. E. Abdalla  F. O. Suliman  H. Al-Ajmi  T. Al-Hosni  H. Rollinson 《Environmental Earth Sciences》2010,60(4):885-892

The use of cyanide (CN), which is characterized by volatility, toxicity and high odor, in gold mining is scarcely addressed in the literature and remain controversial. Environmentalists oppose CN usage as it potentially poses serious environmental threats, whereas economic and mining geologists are in favor of its usage for its extracting capacity and economic feasibility. The present study investigates the possible dispersion of CN into groundwater resources caused by a gold mine (ca. 15 years old) located in the arid area of Yanqul, North Oman. The gold is hosted in gossan deposits associated with ophiolitic rocks and sulfide deposits. Sodium cyanide is mixed with 0.5 m³ of water and then added to a tonne of crushed ore rock to extract 6 g of gold mineral. The final residues are dumped in engineered, lined and uncovered tailing dams. Subsequent to rainfall water draining the mine plateau flows along the wadies and percolates into the shallow Quaternary alluvium aquifer. Hence, groundwater samples were collected from 16 piezometers adjacent to and around the mine. The samples were analyzed for CN using the revised phenolphthalin method and they all show CN concentration below the detection limit (5 ppb). The samples were also analyzed for heavy metals to investigate the potential of CN complexation. Most of heavy metals indicated very trace concentration. The absence of CN in groundwater is attributed to volatilization of CN (converted to HCN), lined dam structure, high evapotranspiration rate and deeper water table. This finding is consistent with the historical CN analysis in the groundwater and solid wastes. It can be pointed out that within few years of operation well engineered tailing dams can provide safe structure preventing CN-groundwater pollution in arid areas. Potential threats to the air and soil are not addressed in this article.  相似文献   

Application of Wavelet Transform to Magnetic Data Due to Ruins of the Hittite,Civilization in Turkey     

A.?Muhittin AlboraEmail author  Z.?Mümtaz Hisarli  Osman N.?Ucan 《Pure and Applied Geophysics》2004,161(4):907-930

— In the recent years, geophysical methods have been applied successfully in archaeological studies. In this article we have studied the application of wavelet transform to magnetic data in order to estimate boundaries of various synthetic examples and real data. Enhanced Horizontal Derivative (EHD) method is also applied as an alternative method for boundary estimation. The performance of wavelet transform and the EHD method are evaluated using magnetic data of the Sarissa-Kusakli archaeological site. All boundary results are mutually compared. Based on these comparisons, we conclude that the wavelet transform provides reasonable results.This work was supported by the TUBITAK under Project YDABCAG-100Y021.Received: 23 October 2001  相似文献   

Forward Modeling with Forced Neural Networks for Gravity Anomaly Prof?le     

Onur Osman  A. Muhittin Albora  Osman Nuri Ucan 《Mathematical Geology》2007,39(6):593-605

In this paper, we introduce a new method called Forced Neural Network (FNN) to find the parameters of the object in geophysical section respect to gravity anomaly assuming the prismatic model. The aim of the geological modeling is to find the shape and location of underground structure, which cause the anomalies, in 2D cross section. At the first stage, we use one neuron to model the system and apply back propagation algorithm to find out the density difference. At the second level, quantization is applied to the density differences and mean square error of the system is computed. This process goes on until the mean square error of the system is small enough. First, we use FNN to two synthetic data, and then the Sivas–Gürün basin map in Turkey is chosen as a real data application. Anomaly values of the cross section, which is taken from the gravity anomaly map of Sivas–Gürün basin, are very close to those obtained from the proposed method.  相似文献   

Sudan and the Nile Basin   总被引：1，自引：0，他引：1  

Osman El-Tom Hamad  Atta El-Battahani 《Aquatic Sciences - Research Across Boundaries》2005,67(1):28-41

  相似文献   

Lithostratigraphy and tectonic evolution of the Meatiq infrastructure,central eastern desert,Egypt     

Mohamed E. Habib  A.A. Ahmed  Osman M. El-Nady 《Precambrian Research》1982,16(4):A21

  相似文献