Strain Analysis and Microstructural Investigation of the Jabal Tays Ophiolite Complex,Eastern Arabian Shield,Saudi Arabia     

Kassem  O. M. K.  Ibrahim  El Kh. H.  Lashin  A.  Almutari  M. 《Geotectonics》2019,53(6):752-764

Geotectonics - The present study deals with the Jabal Tays ophiolite area, which was affected by Al Amar-Idsas fault. It is one of the most important tectonic features in the Eastern Arabian...  相似文献   

Mineral processing characteristics of natural zeolites from the Aritayn Formation of northeast Jordan     

K. M. Ibrahim  S. D. J. Inglethorpe 《Mineralium Deposita》1996,31(6):589-596

The inferior grade of natural zeolite ores in comparison to their synthetic counterparts has been identified as a possible factor responsible for the relatively small market share of the former. This paper describes the results of laboratory-scale mineral processing trials carried out on relatively low-grade natural zeolite ores from the Aritayn Formation of northeast Jordan to improve their purity through removal of unwanted gangue constituents. Appropriate sample preparation and mineral processing methods were selected which utilised contrasts in texture, particle-size, hardness, specific gravity and magnetic susceptibility between gangue and target constituents to achieve beneficiation. Sample preparation by autogenous comminution was able to selectively liberate zeolite minerals from the surface of pyroclasts and therefore was an effective method of pre-concentration. Subsequently, using widely-available magnetic and gravity separation equipment, a high-grade concentrate containing 89% zeolite was produced at a recovery of 37% from a lapilli tuff of 47% head grade.  相似文献   

Evaluation of Jordanian faujasite tuff by comparison with other natural and synthetic zeolites   总被引：1，自引：0，他引：1  

Khalil M. Ibrahim 《Environmental Geology》2001,40(4-5):440-445

 The evaluation of the Jordanian faujasite tuff in wastewater treatment is investigated by comparison with synthetic faujasite (13X) and clinoptilolite-rich tuff. The material used (JORD-FAUJ) is concentrated by mineral processing techniques. It has a faujasite content of 57% and phillipsite content of 35%. Thorough characterization of the JORD-FAUJ revealed the high suitability of the product for use in column operation. It either compares closely or gives better thermal stability, attrition resistance, acid resistance, cation exchange capacity (CEC) and water absorption capacity, when compared with products already recommended in column operation. The study has also revealed that the JORD-FAUJ competes efficiently in ammonium removal with the synthetic faujasite 13X and clinoptilolite-rich tuff and gives similar performance. JORD-FAUJ gave a very high performance in removing Pb, Cr, Cu, Zn, and Ni from wastewater, equivalent to 83–100% of that of faujasite 13X and much higher than the clinoptilolite-rich tuff. Received: 13 April 2000 · Accepted: 1 August 2000  相似文献   

On a self-consistent representation of earth models,with an application to the computing of internal flattening     

Carlo Denis  Aysel Ibrahim 《Journal of Geodesy》1981,55(3):179-195

Most realistic Earth models published as yet have been given in tabulated form, with the noticeable exception of three simple parametric Earth models derived by Dziewonski et al. (1975). Simple interpolation in these tables may lead to inconsistencies, when we consider certain effects which depend crucially on detailed density structure. We establish algorithmic formulae, which may be used to compute all the mechanical properties of a model in an entirely consistent way, once the density as well asP— andS— wave velocities are known. We then use this formulation to integrate Clairaut’s equation in a very efficient way, and thus obtain the hydrostatic flattening to the first order in smallness at any point inside the model. For most geodynamic purposes, we may suffice with this approximation. Finally, we show the results of some calculations of hydrostatic flattening to the first and second order, using an iterative technique of solving the integral figure equations, for an Earth model consistent with all geophysical data available at present. We find that the hydrostatic flattening at the surface should be about 1/298.8, instead of 1/296.961 as quoted by Nakiboglu (1979) for essentially the same model. Moreover, from our results, we estimate the actual flattening of the coremantle boundary to be about 1/390.3.  相似文献   

Crowdsourced approaches for stage measurements at ungauged locations using smartphones     

Yusuf Sermet  Paul Villanueva  Muhammed Ali Sit  Ibrahim Demir 《水文科学杂志》2020,65(5):813-822

ABSTRACT

The growing availability of smart devices with advanced sensors has increased the opportunities for citizen science applications for environmental monitoring. Accurate and widespread monitoring of river stage is vital for modeling water resources. Reliable data points are required for model calibration and validation in forecast studies. While current embedded monitoring systems provide accurate measurements, the cost to replicate these systems on a large domain is prohibitively expensive, limiting the quantity of data available. This project describes a new method to accurately measure river levels using smartphone sensors. Pictures of the same point on the river’s surface are taken to perform calculations based on the GPS location and spatial orientation of the smartphone. The proposed implementation is significantly more accessible than existing water measuring systems while offering similar accuracy. A case study is performed to evaluate the accuracy and sensitivity of the measurements to changes in distance.  相似文献   

Evidences for a low-velocity core-mantle transition zone     

Abou-Bakr K. Ibrahim 《Physics of the Earth and Planetary Interiors》1973,7(2):199-202

Using the spectral ratios $\text{P}\text{PcP}\text{,}\text{ScS}{}_{\mathrm{n+1}}\text{ScS}{}_{\mathrm{n}}\text{,}\text{sScS}{}_{\mathrm{n+1}}\text{sScS}{}_{\mathrm{n}}\text{and}\text{SKS}\text{ScS}$, models for the core-mantle boundary are found. The models have close similarity with each other, implying an irregular surface with lateral variation in the core-mantle properties. The models are characterized by two to four low-velocity, high-density layers imbedded between the mantle and the core half space. The velocities of the imbedded layers decrease towards the core boundary with a lower bound of 9.3 km/sec for the compressional wave and 3.5 km/sec for the shear wave. The models fitted to the empirical data support the hypothesis of a finite rigid outer core with a higher bound for the shear velocity of 1.4 km/sec. Based on this finite rigidity in the outer core and a layered core-mantle transition zone, the value of Q for the whole mantle is 2,000. For the outer core Q ranges from 100–1,000 , which may indicate that it is chemically zoned.  相似文献   

Mapping Buried Bedrock Topography with Gravity   总被引：3，自引：0，他引：3  

Abdelwahid Ibrahim  William J. Hinze 《Ground water》1972,10(3):18-23

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A reassessment of the human dimension of desertification     

Fouad Ibrahim 《GeoJournal》1993,31(1):5-10

So far, the human dimension of desertification has been confined to some peripheral aspects of desertification. Man is either set at the beginning of the process as a triggerer or at the end as a victim. This paper tries to show the high degree of involvement of human communities in the process of desertification itself and that they undergo degradation just like the vegetation associations and the wildlife communities. A new, more human-orientated definition of desertification is discussed here.  相似文献   

Finite element versus simplified methods in the seismic analysis of underground structures     

Alberto Gmez-mass  Ibrahim Attalla 《地震工程与结构动力学》1984,12(3):347-367

Seismic analysis of buried tunnels is considered herein. A comparison of results is carried out between a detailed finite element analysis and several simplified models for hand calculation. The finite element analysis is conducted by superimposing the free field motions and the interaction motions. The latter are calculated in a plane strain geometry taking into account the influence of adjacent structures with an approximation for 3-D effects and for soil non-linearities. Simplified models give, in general, conservative results, although better approximations are obtained by modelling the tunnel bends, where stress concentration occurs.  相似文献   

Reply to Whitney and Regnier’s comments regarding “Monazite Ages and the Evolution of the Menderes Massif, western Turkey” (Int J Earth Sci 94:204–217)     

E.J. Catlos  Ibrahim Çemen 《International Journal of Earth Sciences》2006,95(2):352-354

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