A Unified Computational Method for Simulating Dynamic Behavior of Planing Vessels     

Mohammad Saeed SEIF  Ebrahim JAHANBAKHSH  Roozbeh PANAHI  Mohammad Hossein KARIMI 《中国海洋工程》2009,23(3):517-528

High speed planing hulls have complex hydrodynamic behaviors. The trim angle and drafts are very sensitive to speed and location of the center of gravity. Therefore, motion simulation for such vessels needs a strong coupling between rigid body motions and hydrodynamic analysis. In addition, free surface should be predicted with good accuracy for each time step. In this paper, velocity and pressure fields are coupled by use of the fractional step method. On the basis of integration of the two-phase viscous f...  相似文献   

Analytical model of strange star in low-mass X-ray binary KS 1731-260     

Sk. Monowar Hossein  Nur Farhad  Sajahan Molla  Mehedi Kalam 《Astrophysics and Space Science》2016,361(10):333

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Hydrological drought in the west of Iran and possible association with large‐scale atmospheric circulation patterns          下载免费PDF全文

P. Hosseinzadeh Talaee  Hossein Tabari  S. Sobhan Ardakani 《水文研究》2014,28(3):764-773

Drought is a slow‐onset, creeping natural hazard which is an inevitable part of normal climate fluctuation especially in arid and semiarid regions, and its variability can be explained in terms of large‐scale atmospheric circulation patterns. Standardized streamflow index (SSFI) was utilized to characterize hydrological drought in the west of Iran for the hydrological years of 1969–1970 to 2008–2009. The linkage of atmospheric circulation patterns (ENSO, NAO) to hydrological drought was also used to reveal relations of climate variability affecting hydrological drought. River discharges exhibited negative anomalies during the warm phase of ENSO (El Niño) which caused the extreme and severe droughts in the study area, being strongest during the hydrological years of 2007–2008 and 2008–2009. The analysis also indicated the teleconnection impact of ENSO on the hydrological drought severity in the first half of the hydrological year especially between November and March. Moreover, the concurrent and lag correlations revealed a weak relationship between the SSFI drought severity and the NAO index. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Probabilistic analysis of an 80,000 m2 landslide in Shiraz,Iran     

Shafiee  Amir Hossein  Falamaki  Amin  Shafiee  Ali  Arjmand  Farzad 《Landslides》2022,19(3):659-671

Landslides - Each year, so many devastating landslides occur all around the world causing a lot of life and economical losses. Many of these landslides take place in large populated cities where...  相似文献   

Rock Type Identification Using Analysis of the Acoustic Signal Frequency Contents Propagated While Drilling Operation     

Khoshouei  Mehrbod  Bagherpour  Raheb  Jalalian  Mohammad Hossein 《Geotechnical and Geological Engineering》2022,40(3):1237-1250

Geotechnical and Geological Engineering - One of the most important parameters specially in mining and oil drilling fields is the type of rocks. It is important to determine that rock structure is...  相似文献   

First Record of Sexual Dimorphism in Toxasterid Echinoid Heteraster from the Early Cretaceous Deposits of the Kopet-Dagh Basin,NE Iran     

Hossein KAMYABI SHADAN  Morteza TAHERPOUR KHALIL-ABAD 《《地质学报》英文版》2023,97(5):1318-1334

Spatangoid echinoids belonging to Heteraster found in the Lower Cretaceous limestones and calcareous deposits of the Tirgan and Sarcheshmeh formations(Barremian–Aptian) in the Bahman jan-Bala stratigraphic section on the northern flank of the Borouj syncline, situated in the eastern Kopet-Dagh Basin, northeastern Iran are assessed as a sexually dimorphic species. Sexual dimorphism is a common feature in echinoids and, in this study of Heteraster renngarteni Poretzkaja, 1961, sexual dimorphism ha...  相似文献   

Performance evaluation of the M8 algorithm to predict M7+ earthquakes in Turkey     

Masoud Mojarab  Hossein Memarian  Mehdi Zare 《Arabian Journal of Geosciences》2015,8(8):5921-5934

The M8 algorithm is one of the most reliable intermediate-term middle-range earthquake prediction algorithms. The present study evaluates the ability of the M8 algorithm and its modified versions for predicting major events (M7+) in Turkey. Thirty different algorithms were developed by changing the radius of circle of investigation (CI) and the lower magnitude cutoff of the M8 algorithm. These modified algorithms were executed all over the territory of Turkey, and the results were evaluated using the error diagram. Each modified algorithm was executed for consecutive half-year intervals over a specified period of time. Subsequently, the seismic catalog was updated, and failures-to-predict ratio and the fraction of alarm were considered. Results showed that the location of areas of alarm change gradually over consecutive intervals, and no sudden changes can be observed. In addition, the annual changes of areas of alarm are not random and follow a pattern. This study also showed that the modified algorithm having a three to six annual average of events and a 393-km CI radius is an efficient algorithm for predicting the future seismic events in Turkey. This algorithm predicted six out of six target events, retrospectively, with a confidence level of 96.4 %. According to the obtained results, it will be possible to rely on this modified algorithm to predict near future earthquakes of Turkey. Furthermore, this study proves that it is possible to alter the M8 algorithm for being used in regional studies.  相似文献   

A comparison between karst development in two main zones of Iran: case study—Keyno anticline (Zagros Range) and Shotori anticline (Central Iran)     

Manouchehr Chitsazan  Hossein Karimi Vardanjani  Haji Karimi  Abbas Charchi 《Arabian Journal of Geosciences》2015,8(12):10833-10844

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Facies Analysis and Sequence Stratigraphy of Silurian Carbonate Ramps in the Turan (Kopeh-Dagh) and Central Iran Plates with Emphasis on Gondwana Tectonic Event     

Zohreh NOWROUZI  Asadollah MAHBOUBI  Reza MOUSSAVI-HARAMI  Mohammad Hossein MAHMUDY GHARAIE  Farzin GHAEMI 《《地质学报》英文版》2015,89(4):1276-1295

Two sections from the Silurian deposits in the Central Iran Micro and Turan Plates were measured and sampled. These deposits are mostly composed of submarine volcanic rocks, skeletal and non-skeletal limestone, shale and sandstone that were deposited in low to high energy conditions (from tidal flat to deep open marine). According to gradual deepening trend, wide lateral distribution of facies as well as absence of resedimentation deposits, a depositional model of a homoclinal ramp was proposed for these deposits. Field observations and facies distribution indicate that, two depositional sequences were recognized in both sections. These sections show similarities in facies and depositional sequence during the Early Silurian in the area. Although there are some opinions and evidences that demonstrated Paleo-Tethys rifting phase started at the Late Ordovician-Early Silurian, similarities suggest that the Turan and Iran Plates were not completely detached tectonic block during this time, and that their depositional conditions were affected by global sea level changes and tectonic events.  相似文献   

Comparison of linear and nonlinear forms of isotherm models for Zn(II) and Cu(II) sorption on a kaolinite     

Shahram?Shahmohammadi-KalalaghEmail author  Hossein?Babazadeh  Amirhossein?Nazemi 《Arabian Journal of Geosciences》2015,8(1):397-402

The most appropriate method in designing the adsorption systems and assessing the performance of the adsorption systems is to have an idea on adsorption isotherms. Comparison analysis of linear least square method and nonlinear method for estimating the isotherm parameters was made using the experimental equilibrium data of Zn(II) and Cu(II) onto kaolinite. Equilibrium data were fitted to Freundlich, Langmuir, and Redlich–Peterson isotherm equations. In order to confirm the best-fit isotherms for the adsorption system, the data set using the chi-square (χ ²), combined with the values of the determined coefficient (r ²) was analyzed. Nonlinear method was found to be a more appropriate method for estimating the isotherm parameters. The best fitting isotherm was the Langmuir and Redlich–Peterson isotherm. The Redlich–Peterson is a special case of Langmuir when the Redlich–Peterson isotherm constant g was unity. The sorption capacity of kaolinite to uptake metal ions in the increasing order was given by Cu (4.2721 mg/g)?<?Zn (4.6710 mg/g).  相似文献