A catalogue of spectral classification and photometric data of B-type stars     

M. A. Hamdy  M. S. Abo Elazm  S. M. Saad 《Astrophysics and Space Science》1993,203(1):53-107

The present work represents a catalogue of spectral classification and photometric data of 2047 B type stars using the Q method.  相似文献   

Spectral reclassification of some Be stars using ΔQ method     

M. A. Hamdy  M. S. Abo Elazm  S. M. Saad 《Astrophysics and Space Science》1991,186(1):161-164

The present work shows how the new defined value Q can play a role in spectral reclassification of Be stars.  相似文献   

<Emphasis Type="Italic">Integrated Remote Sensing and</Emphasis> Structural Analysis Studies of Tayyib Al-Ism Area,Northwestern Arabian Shield,Saudi Arabia     

Osama M. K. Kassem  Habes A. Ghrefat  Haider Zaman  Awni T. Batayneh  Saad Almogren  Yousef Nazzal  Eslam Elawadi 《Journal of the Indian Society of Remote Sensing》2016,44(1):91-99

Geological and structural mappings of Tayyib Al-Ism area were carried out using the rocks finite strain data, the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) data and the field based observations. To analyze the finite strain in the studied rocks, the R_f /? and Fry methods are applied to feldspar porphyroclasts and mafic grains from nine metavolcano-sedimentary samples (Hegaf Formation), four diorite-gabbros suite samples (Sawawin Complex), two meta-granite samples (Ifal suite) and five Zuhd alkali granite samples. The obtained data indicate traces of high to moderate level of deformation in the meta-granite and metavolcano-sedimentary rocks. The axial ratios along the XZ section range from 1.70 to 4.80 for the R_f/? method and from 1.50 to 4.50 for the Fry method. A sub-vertical trend of short axes in association with sub-horizontal foliation is also observed. These informations allow us to conclude that a finite strain in the deformed granitic rocks is of the same order of magnitude as in the metavolcano-sedimentary rocks. The contacts between the metavolcano-sedimentary and granitic rocks in Tayyib al Ism area were formed during the granitic intrusions along some of the faults under brittle to semi-ductile deformation conditions. These faults have significantly influenced the geometry and style of rifting in the Red Sea during the Neogene. The finite strain was accumulated in the area during the process of deformation, which superimpose the already existed nappe structure. It indicates that the nappe contacts formed during the accumulation of finite strain. In addition to finite strain analysis, band ratio images (3/1, 5/3, 7/5) and Principal Component Analysis (PCA) technique have been used, which proved effective in mapping geological and structural features of various rock bodies exposed in the study area.  相似文献   

An integrated geophysical study for inferring the subsurface setting of water-bearing aquifers: case study at Wadi al-Dawasir area,Saudi Arabia     

Abdulsalam Al Asmari  Saad Mogren  Aref Lashin  Mohamed Hussein  Fouzan Al Fouzan 《Environmental Earth Sciences》2016,75(12):1028

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Potential of support vector regression for solar radiation prediction in Nigeria     

Lanre Olatomiwa  Saad Mekhilef  Shahaboddin Shamshirband  Dalibor Petkovic 《Natural Hazards》2015,77(2):1055-1068

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Erratum to: Rift to post-rift evolution of a ‘‘passive’’ continental margin: the Ponta Grossa Arch, SE Brazil     

A. O. B. Franco-Magalhaes  P. C. Hackspacher  U. A. Glasmacher  A. R. Saad 《International Journal of Earth Sciences》2010,99(7):1615-1617

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Microstructural weathering of sedimentary rocks by freeze–thaw cycles: Experimental study of state and transfer parameters     

Alice Saad  Sylvine GuédonFrançois Martineau 《Comptes Rendus Geoscience》2010,342(3):197-203

The frost sensitivity of a rock is resulting from the combined action of processes linked to porous network characteristics (state parameters) and to the way water flows into this porous network (transfer parameters), our study was thus about the influence of these parameters on frost weathering of rocks. Sedimentary rocks often found on buildings (limestone and sandstone) and consequently submitted to temperature variations have been selected. State and transfer parameters have been measured for sample characterization and the follow-up of weathering during freeze–thaw cycles. The coupled influence of a state parameter (dynamic modulus of elasticity) and a transfer parameter (water permeability), i.e. between rock skeletal strength and voids connection, has thus been discussed.  相似文献   

RETRACTED ARTICLE: Depositional environments and porosity distribution in regressive limestone reservoirs of the Mishrif Formation,Southern Iraq     

Moutaz Al-Dabbas  Jassim Al-Jassim  Saad Al-Jumaily 《Arabian Journal of Geosciences》2010,3(1):67-78

Eight subsurface sections and a large number of thin sections of the Mishrif Limestone were studied to unravel the depositional facies and environments. The allochems in the Mishrif Formation are dominated by bioclasts, whereas peloids, ooids, and intraclasts are less abundant. The sedimentary microfacies of the Mishrif Formation includes mudstone, wackestone, packstone, grainstone, floatstone, and rudstone, which have been deposited in basinal, outer shelf, slop followed by shoal reef and lagoonal environments. The formation displays various extents of dolomitization and is cemented by calcite and dolomite. The formation has gradational contact with the underlying Rumaila Formation but is unconformably overlain by the Khasib Formation. The unconformity is recognized because the skeletal grains are dominated by Chaophyta (algae), which denotes the change of environment from fully marine to lacustrine environment. Thus, the vertical bioclast analysis indicates that the Mishrif Formation is characterized by two regressive cycles, which control the distribution of reservoir quality as well as the patterns of calcite and dolomite cement distribution. Mishrif Formation gradationally overlies Rumaila Formation. This was indicated by the presence of the green parts of Chaophyta (algae) as main skeletal grains at the uppermost part of well Zb-47, which refer to lacustrine or fresh water environment. Petrographical study shows that the fossils, peloids, oolitis, and intraclasts represent the main allochem. Calcite and dolomite (as diagenetic products) are the predominant mineral components of Mishrif Formation. Fossils were studied as an environmental age and facial boundaries indicators, which are located in a chart using personal computer programs depending on their distributions on the first appearance of species. Fifteen principal sedimentary microfacies have been identified in the Mishrif Formation, which includes lime mudstone, mudstone–wackestone, wackestone, wackestone–packstone, packstone, packstone–grainstone, grainstone–floatstone, packstone–floatstone, packstone–rudstone, and wackestone–floatstone. Markov chain analysis has been used to study the transitional pattern of different microfacies types vertically in each well and laterally in all wells as a composite section. The vertical analysis indicates that the Mishrif Formation characterized by two regressive cycles, the main one started with basinal or outer shelf environment, slop environment followed by shoal or reefal environment, and ended with a lagoonal environment. The lateral analysis shows the same regressive cycle, and by using the lithofacies association concepts, we built the depositional model of the Mishrif Formation environment.  相似文献   

Spectrum Disentangling and Orbital Solution for κ Dra     

S. M. Saad  J. Kubát  P. Hadrava  P. Harmanec  P. Koubský  P. Škoda  M. Šlechta  D. Korčáková  S. Yang 《Astrophysics and Space Science》2005,296(1-4):173-177

Based on a new set of electronic spectra in a relatively wide spectral range (3500–8300 Å) and using the methods of spectrum disentangling (code KOREL) and solution of RV curves (code FOTEL), we determined new orbital elements of the binary star κ Dra. The solution of the radial velocity curves for Balmer and some other strong metallic lines suggested a circular orbit and led to the following orbital elements: period P = 61.555 ± 0.029 days, epoch of periastron passage T _periast = 49980.22 ± 0.59, RV semi-amplitude K ₁ = 6.81 ± 0.24 km s^?1, and a mass function of f(m) = 0.002 M _⊙. Lines of the secondary were not detected. In addition, moving absorption bumps in the violet peaks of Hα and Hβ lines were found to be phase-locked with the orbital period. Their presence suggests some kind of interaction between the binary components.  相似文献   

Effects of stepwise variation of single-scattering albedo on reflectivity and transmissivity of a linear-anisotropically scattering slab     

S. A. El Wakil  M. S. Abdel Krim  E. A. Saad 《Astrophysics and Space Science》1987,135(2):219-228

Unsteady free-convection flows near an infinite vertical plate in a rotating medium in the presence of a constant transverse magnetic field are investigated under an arbitrary time-dependent heating of the plate. By using the Laplace transform technique, the Green's function of the problem is determined and exact solutions are obtained for special cases of the time-dependent heating effect. The thermal influence on skin friction at the plate and the displacement thickness of the boundary layer are determined, and the structure of the thermal wave trains is discussed.Formerly Kulshrestha.  相似文献