Fourier analysis of the light changes of four Algol-type eclipsing variables     

Hamid M. K. Al-Naimiy  Assem O. Al-Sikab 《Astrophysics and Space Science》1984,103(1):115-124

The aim of the present paper is to present the analysis of the light curves of four totally-eclipsing systems (BM Ori, VW Cyg, TW Dra, and RW Mon), using the automated Fourier techniques in the frequency-domain, developed recently by Kopal and his school at Manchester University.New Physical and geometrical elements for the above systems are derived.  相似文献   

The Iraqi National Astronomical Observatory     

Hamid M. K. Al-Naimiy 《Astrophysics and Space Science》1986,118(1-2):51-56

Iraq is currently experiencing a praid cultural, scientific, and technical renaissance, and astronomy is a natural focus for the country's pride in the past achievements of the civilization which have flourished in Iraq. The current plans of the Space and Astronomy Research Center (SARC) include building a major observatory to work in the optical, IR and radio region of the spectrum.The core of the optical facility will be a 3.5 m optical telescope, together with 1.25 m telescope designed for efficient performance in the IR. These telescopes will be equipped with instruments for photographic, photometric and spectroscopic observations. A 30 m dish is also being built for millimeter/radio observations.SARC has selected an excellent observing site in the northern mountains of Iraq which has good seeing and clear dark skies. The sites selection was made with the collaboration of several leading astronomers and observatories from various countries.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984  相似文献   

A Geometric Computational Model for Calculation of Longwall Face Effect on Gate Roadways     

Hamid Mohammadi  Mohammad Ali Ebrahimi Farsangi  Hossein Jalalifar  Ali Reza Ahmadi 《Rock Mechanics and Rock Engineering》2016,49(1):303-314

In this paper a geometric computational model (GCM) has been developed for calculating the effect of longwall face on the extension of excavation-damaged zone (EDZ) above the gate roadways (main and tail gates), considering the advance longwall mining method. In this model, the stability of gate roadways are investigated based on loading effects due to EDZ and caving zone (CZ) above the longwall face, which can extend the EDZ size. The structure of GCM depends on four important factors: (1) geomechanical properties of hanging wall, (2) dip and thickness of coal seam, (3) CZ characteristics, and (4) pillar width. The investigations demonstrated that the extension of EDZ is a function of pillar width. Considering the effect of pillar width, new mathematical relationships were presented to calculate the face influence coefficient and characteristics of extended EDZ. Furthermore, taking GCM into account, a computational algorithm for stability analysis of gate roadways was suggested. Validation was carried out through instrumentation and monitoring results of a longwall face at Parvade-2 coal mine in Tabas, Iran, demonstrating good agreement between the new model and measured results. Finally, a sensitivity analysis was carried out on the effect of pillar width, bearing capacity of support system and coal seam dip.  相似文献   

Incorporation of chitosan and glass substrate for improvement in adsorption,separation, and stability of TiO<Subscript>2</Subscript> photodegradation     

M. N. I. Amir  N. M. Julkapli  S. B. Abd Hamid 《International Journal of Environmental Science and Technology》2016,13(3):865-874

It is demonstrated that single titanium dioxide (TiO₂) has high potential for photodegradation of pollutants. However, it is still far from becoming an effective photocatalyst system, due to issues of adsorption process, separation, as well as dissolution. Therefore, this study highlights the high adsorption capacity, simplified separation, and the promising stability of TiO_2(SY) (synthesized via sol–gel method) photocatalyst, fabricated using chitosan–TiO_2(SY) and supported by glass substrate (Cs–TiO_2(SY)/glass substrate) photocatalysts. Chitosan (Cs), with abundant –R–NH and NH₂ groups, promotes the adsorption sites of methyl orange (MO) and OH groups for major attachment to TiO_2(SY). Meanwhile, the glass substrate increases stability and assists separation of the photocatalysts. Initially, nano-TiO_2(SY) has been characterized using high-resolution transmission electron microscope. Cs–TiO_2(SY)/glass substrate was fabricated via dip-coating. The distribution and interface between the photocatalytic components were characterized by Fourier transform infrared absorption spectroscopy, UV–Vis diffuse reflectance spectroscopy, field emission scanning electron microscopy, and energy-dispersive spectrometer. UV–Vis analysis of the multilayer photocatalyst (2, 4, 6, and 8 layers) was further carried out by the adsorption–photodegradation, with MO as model of pollutant. Seventy percent of the total removal of MO via optimized eight layers of photocatalyst was achieved within 1 h of UV irradiation. The adsorption photocatalyst achieved 50 % with no exposure to UV light for 15 min of irradiation. It is concluded that suitable photocatalytic conditions and sample parameters possessing the multilayer photocatalyst of Cs–TiO_2(SY) are beneficial toward the adsorption–photodegradation process in wastewater treatment.  相似文献   

Flood susceptibility mapping using frequency ratio and weights-of-evidence models in the Golastan Province,Iran     

Omid Rahmati  Hamid Reza Pourghasemi  Hossein Zeinivand 《国际地球制图》2016,31(1):42-70

Flood is one of the most devastating natural disasters with socio-economic and environmental consequences. Thus, comprehensive flood management is essential to reduce the flood effects on human lives and livelihoods. The main goal of this study was to investigate the application of the frequency ratio (FR) and weights-of-evidence (WofE) models for flood susceptibility mapping in the Golestan Province, Iran. At first, a flood inventory map was prepared using Iranian Water Resources Department and extensive field surveys. In total, 144 flood locations were identified in the study area. Of these, 101 (70%) floods were randomly selected as training data and the remaining 43 (30%) cases were used for the validation purposes. In the next step, flood conditioning factors such as lithology, land-use, distance from rivers, soil texture, slope angle, slope aspect, plan curvature, topographic wetness index (TWI) and altitude were prepared from the spatial database. Subsequently, the receiver operating characteristic (ROC) curves were drawn for produced flood susceptibility maps and the area under the curves (AUCs) was computed. The final results indicated that the FR (AUC = 76.47%) and WofE (AUC = 74.74%) models have almost similar and reasonable results. Therefore, these flood susceptibility maps can be useful for researchers and planner in flood mitigation strategies.  相似文献   

A Comparison Study of ORASIS and VCA for Mineralogical Unmixing of Hyperspectral Data     

Tohid Nouri  Majid M. Oskouei  Hamid Zekri 《Journal of the Indian Society of Remote Sensing》2016,44(5):723-733

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Improving the Accuracy of Land Cover Classification Using Fusion of Polarimetric SAR and Hyperspectral Images     

Mahin Shokrollahi  Hamid Ebadi 《Journal of the Indian Society of Remote Sensing》2016,44(6):1017-1024

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An active time-optimal control for space debris deorbiting via geomagnetic field     

M. A. Amiri Atashgah  Hamid Gazerpour  Abolfazl Lavaei  Yaser Zarei 《Celestial Mechanics and Dynamical Astronomy》2017,128(2-3):343-360

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Probabilistic analyses of soil consolidation by prefabricated vertical drains for single‐drain and multi‐drain systems          下载免费PDF全文

Mohammad Wasiul Bari  Mohamed A. Shahin  Abdul‐Hamid Soubra 《国际地质力学数值与分析法杂志》2016,40(17):2398-2420

Natural soils are one of the most inherently variables in the ground. Although the significance of inherent soil variability in relation to reliable predictions of consolidation rates of soil deposits has long been realized, there have been few studies that addressed the issue of soil variability for the problem of ground improvement by prefabricated vertical drains. Despite showing valuable insights into the impact of soil spatial variability on soil consolidation by prefabricated vertical drains, available stochastic works on this subject are based on a single‐drain (or unit cell) analyses. However, how the idealized unit cell solution can be a supplement to the complex multi‐drain systems for spatially variable soils has never been addressed in the literature. In this study, a rigorous stochastic finite elements modeling approach that allows the true nature of soil spatial variability to be considered in a reliable and quantifiable manner, both for the single‐drain and multi‐drain systems, is presented. The feasibility of performing an analysis based on the unit cell concept as compared with the multi‐drain analysis is assessed in a probabilistic context. It is shown that with proper input statistics representative of a particular domain of interest, both the single‐drain and multi‐drain analyses yield almost identical results. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Correction to: Geochemical Prospectivity Mapping Through a Feature Extraction–Selection Classification Scheme     

Zekri  Hamid  Cohen  David R.  Mokhtari  Ahmad Reza  Esmaeili  Abbas 《Natural Resources Research》2019,28(3):867-868

Natural Resources Research - The original version of this article unfortunately contained a mistake in the second part of Table&nbsp;3. The data in last four rows of Table&nbsp;3, i.e.,...  相似文献