Hematite grains: Size and coercive force from AF demagnetization at high temperatures     

Mohamad Mansour Bina  Michel Prévot 《Physics of the Earth and Planetary Interiors》1977,13(4):272-275

The coercivity spectrum of low-field high-temperature partial thermoremanent magnetization (PTRM) of a synthetic hematite powder, extremely high at room temperature, decreases very slowly with increasing temperature up to 500°C then decreases rapidly, especially above 600°C. From the AF demagnetization curves at 600 and 650°C it is calculated, following the Néel's theory of single-domain particles that the grains carrying the PTRM have a mean coercive force of 23 ± 5 kOe and a mean grain size of 0.40 ± 0.15 μm, which is not significantly different from the mean grain size of 0.48 ± 0.03 μm from electron micrograph observations.  相似文献   

In Situ Soil Remediation Using Vapor Extraction Wells, Development and Testing of a Three-Dimensional Finite-Difference Model     

Mansour Sepehr  Zohrab A. Samani 《Ground water》1993,31(3):425-436

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Extraction of TCE-Contaminated Ground Water by Subsurface Drains and a Pumping Well     

David Meiri  Mansour Ghiasi  Ronald J. Patterson  Narayan Ramanujam  Mary P. Tyson 《Ground water》1990,28(1):17-24

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Estimation of ship motions using closed-form expressions   总被引：1，自引：0，他引：1  

Jrgen Juncher Jensen  Alaa E. Mansour  Anders Smrup Olsen 《Ocean Engineering》2004,31(1):61-85

A semi-analytical approach is used to derive frequency response functions for the wave-induced motions for monohull ships. The results are given as closed-form expressions and the required input information for the procedure is restricted to the main dimensions: length, breadth, draught, block coefficient and water plane area together with speed and heading. The formulas make it simple to obtain quick estimates of the wave-induced motions and accelerations in the conceptual design phase and to perform a sensitivity study of the variation with main dimensions and operational profile.  相似文献   

The diffraction of linear waves by a uniform vertical cylinder with cosine-type radial perturbations     

Alaa M. Mansour  A. Neil Williams  K. H. Wang 《Ocean Engineering》2002,29(3):239-259

The interaction of linear waves with a uniform, bottom-mounted, surface-piercing cylinder whose diameter exhibits a cosine-type variation is investigated. Two solution methods are presented. One method is based on a perturbation theory, using a perturbation parameter defined in terms of the surface geometry of the cylinder. The analysis includes terms up to the first-order in this parameter, where the zeroth-order solution corresponds to a circular cylinder. The velocity potentials at the zeroth and first orders are expressed as eigenfunction expansions involving unknown coefficients that are subsequently determined through the cylinder boundary conditions. The second method is based on Green's theorem and gives rise to an integral equation for the fluid velocity potential on the cylinder surface. A comparison between the results of these two methods has proved that they are in good agreement for small values of the perturbation parameter. Numerical results are presented that illustrate the influence of the magnitude and frequency of these perturbations on the resulting hydrodynamic force and the wave runup on the cylinder.  相似文献   

High-resolution coastal hazard assessment along the French Riviera from co-seismic tsunamis generated in the Ligurian fault system     

Nemati  Fatemeh  Grilli  Stephan T.  Ioualalen  Mansour  Boschetti  Laurie  Larroque  Christophe  Trevisan  Jenny 《Natural Hazards》2019,96(2):553-586

Natural Hazards - The French Riviera is a densely populated and touristic coast. It is also one of the most seismically active areas of the Western Mediterranean. This is evidenced by the Mw...  相似文献   

Interpretation of spontaneous potential anomalies from some simple geometrically shaped bodies using neural network inversion     

Mansour A. Al-Garni 《Acta Geophysica》2010,58(1):143-162

A new approach is proposed in order to interpret spontaneous potential (self-potential) anomalies related to simple geometric-shaped models such as sphere, horizontal cylinder, and vertical cylinder. This approach is mainly based on using neural network inversion of SP anomalies, particularly modular algorithm, for estimating the parameters of different simple geometrical bodies. However, Hilbert transforms are involved to determine the origin location in order to reduce the parameters which minimize the ambiguity in the inverted models. The inversion has been tested first on synthetic data from different models, using only one well-trained network. The results of inversion show that the parameter values derived by the inversion are identical to the true values of parameters. Noise analysis has been also examined, where the results of the inversion produce acceptable results up to 10% of white Gaussian noise. The validity of the neural network inversion is demonstrated through published real field SP taken from southern Bavarian Woods, Germany. A comparable and acceptable agreement is shown between the results of inversion derived by the neural network and those from the real field data.  相似文献   

Diffracted ScS and the Shear Velocity at the Core Boundary     

Bruce A. Bolt  Mansour Niazi  M. R. Somerville 《Geophysical Journal International》1970,19(3):299-305

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Lithostratigraphy of Sheikh Shadli metavolcanics and the older metasediments in Um Samiuki district,eastern desert,Egypt     

N.M. Shukri  M.S. Mansour 《Precambrian Research》1978,6(1):A36-A37

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Characteristics of the internal and external sources of the Mediterranean synoptic cyclones for the period 1956–2013     

Mansour?AlmazrouiEmail author  Adel?M.?Awad  M.?Nazrul Islam 《Theoretical and Applied Climatology》2018,133(3-4):811-827

This paper investigates the main sources and features of the Mediterranean synoptic cyclones affecting the basin, using the cyclone tracks. The cyclones’ tracks are identified using sea level pressure (SLP) from the NCEP/NCAR reanalysis data for the period 1956–2013. The identified cyclones are classified into two categories: basin affected and basin non-affected. Most of the basin-affected (non-affected) cyclones are internal (external), i.e., generated inside (outside) the Mediterranean basin. This study reveals four (five) main sources of internal (external) cyclones. These four (five) main sources generated about 63.76% (57.25%) of the internal (external) cyclones. Seasonal analysis shows that most of the basin-affected internal (external) cyclones were generated in the winter (spring) season. The lowest number of cyclones were found in the summer. Moreover, the synoptic study of the atmospheric systems accompanied the highest- and lowest-generated years demonstrates that the deepening of the north Europe cyclones and the relative positions of Azores- and Siberian-high systems represent the important factors that influence the number of internal cyclones. Essential factors influencing the external cyclones are the strength of the maximum upper wind, Azores high, Siberian high, and orientations of their ridges.  相似文献