Textural Quantification and Classification of Drill Cores for Geometallurgy: Moving Toward 3D with X-ray Microcomputed Tomography (µCT)     

Guntoro  Pratama Istiadi  Ghorbani  Yousef  Butcher  Alan R.  Kuva  Jukka  Rosenkranz  Jan 《Natural Resources Research》2020,29(6):3547-3565

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Numerical experiments on dynamo action in sheared and rotating turbulence     

T. A. Yousef  T. Heinemann  F. Rincon  A. A. Schekochihin  N. Kleeorin  I. Rogachevskii  S. C. Cowley  J. C. McWilliams 《Astronomische Nachrichten》2008,329(7):737-749

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A ground motion prediction equation for JMA instrumental seismic intensity for shallow crustal earthquakes in active tectonic regimes     

Kenneth W. Campbell  Yousef Bozorgnia 《地震工程与结构动力学》2011,40(4):413-427

The JMA (Japan Meteorological Agency) seismic intensity scale has been used in Japan as a measure of earthquake ground shaking effects since 1949. It has traditionally been assessed after an earthquake based on the judgment of JMA officials. In 1996 the scale was revised as an instrumental seismic intensity measure (I_JMA) that could be used to rapidly assess the expected damage after an earthquake without having to conduct a survey. Since its revision, Japanese researchers have developed several ground motion prediction equations (GMPEs) for I_JMA using Japanese ground motion data. In this paper, we develop a new empirical GMPE for I_JMA based on the strong motion database and functional forms used to develop similar GMPEs for peak response parameters as part of the PEER (Pacific Earthquake Engineering Research Center) Next Generation Attenuation (NGA) project. We consider this relationship to be valid for shallow crustal earthquakes in active tectonic regimes for moment magnitudes ( M ) ranging from 5.0 up to 7.5–8.5 (depending on fault mechanism) and rupture distances ranging from 0 to 200 km. A comparison of this GMPE with relationships developed by Japanese researchers for crustal and shallow subduction earthquakes shows relatively good agreement among all of the relationships at M 7.0 but relatively poor agreement at small magnitudes. Our GMPE predicts the highest intensities at small magnitudes, which together with research on other ground motion parameters, indicates that it provides conservative or upwardly biased estimates of I_JMA for M <5.5. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Fuzzy analytical hierarchy process and GIS for predictive Cu porphyry potential mapping: a case study in Ahar–Arasbaran Zone (NW, Iran)     

Kaveh Pazand  Ardeshir Hezarkhani  Yousef Ghanbari 《Arabian Journal of Geosciences》2014,7(1):241-251

Selection of potential areas for mineral exploration is a complex process and needs many diverse criteria. Combining analytic hierarchy process (AHP) modeling with geographic information system (GIS) provides an effective means for studies of mineral potential mapping evaluation. Fuzzy AHP is an extension of conventional AHP and by using fuzzy theory is obtained the advantage rather AHP method. In this paper to provide, potential mapping for Cu porphyry mineralization used fuzzy AHP and GIS in the Ahar–Arasbaran areas, several criteria, such as geology, geochemical and geophysical data, alteration, and faults were used. Each criterion was evaluated with the aid of fuzzy AHP and mapped by GIS. The method allowed a mixture of quantitative and qualitative information with group decision. The results and its validation demonstrate the acceptable outcomes for copper porphyry exploration.  相似文献   

On a Bernoulli's integral pertaining to gas flow in close binary systems     

Yousef Sobouti 《Astrophysics and Space Science》1971,12(2):408-410

A Bernoulli's integral supplemented with the equation of continuity provides a solution for the motion of gas surrounding a binary system.There exist two velocity modes whose streamlines are confined within appropriate equipotential surfaces.  相似文献   

Conditionally-periodic solutions of the Hamiltonian systems with multiple resonance     

M. K. M. Ahmed  M. H. A. Yousef 《Earth, Moon, and Planets》1988,43(3):289-298

A method is developed to construct conditionally periodic solutions of Hamiltonian systems in the case of deep resonance and in the presence of more than one resonant vector (multiple resonance). The method depends on modification of a standard perturbation method. It is applicable to systems with more than one degree of freedom.  相似文献   

Parameter estimation of copula functions using an optimization-based method     

Amin?AbdiEmail author  Yousef?Hassanzadeh  Siamak?Talatahari  Ahmad?Fakheri-Fard  Rasoul?Mirabbasi 《Theoretical and Applied Climatology》2017,129(1-2):21-32

Application of the copulas can be useful for the accurate multivariate frequency analysis of hydrological phenomena. There are many copula functions and some methods were proposed for estimating the copula parameters. Since the copula functions are mathematically complicated, estimating of the copula parameter is an effortful work. In the present study, an optimization-based method (OBM) is proposed to obtain the parameters of copulas. The usefulness of the proposed method is illustrated on drought events. For this purpose, three commonly used copulas of Archimedean family, namely, Clayton, Frank, and Gumbel copulas are used to construct the joint probability distribution of drought characteristics of 60 gauging sites located in East-Azarbaijan province, Iran. The performance of OBM was compared with two conventional methods, namely, method of moments and inference function for margins. The results illustrate the supremacy of the OBM to estimate the copula parameters compared to the other considered methods.  相似文献   

Effect of coriolis force on acceleration covariance in MHD turbulent flow of a dusty incompressible fluid     

N. Kishore  Yousef Torabi Golsefid 《Astrophysics and Space Science》1988,150(1):89-101

In the present problem, acceleration covariance in MHD turbulent flow of dusty fluid with Coriolis force have been obtained.The obtained result shows that the defining scalars (r,t), (r, t), (r, t) of the acceleration covariance in the presence of Coriolis force depends on the defining scalars of tensorsQ _ij, H_ij, _i,j,S _ik,jandT _ij,kalready defined in the text.  相似文献   

Type IIIb radio bursts: 80 MHz source position and theoretical model     

Tatsuo Takakura  Shahinaz Yousef 《Solar physics》1975,40(2):421-438

We present Culgoora spectrograph and radioheliograph observations as well as a model of type IIIb bursts; the latter are defined as chains of striae of slow or no frequency drift, the chain as a whole drifting like a normal type III burst.The 80 MHz source positions are studied for a group of IIIb bursts, a IIIb precursor and harmonic pairs of 1:2 frequency ratio. It is found that the IIIb position may vary in a IIIb group. No significant difference was found between the source positions of a IIIb precursor and the following III burst. For one event we found that the fundamental IIIb burst showed a high degree of circular polarization (46%), while its second harmonic, a normal type III burst, was unpolarized.We suggest that the main cause for the striae in type IIIb bursts is the existence of filamentary, density irregularities along the path of the electron stream. The denser filaments initially reduce the value of the density gradient along the electrons' path and thereby enhance their emissions over a small range of plasma frequencies. If the radio emission from the filaments dominates the emission from the ambient rarified plasma, striae appear in the spectrum and a type IIIb burst results. This condition is more easily satisfied at the fundamental frequency and for electron streams of relatively high density.Radiophysics Publication RPP 1758, October, 1974, (2nd version).On leave from the Dept. of Astronomy, University of Tokyo, Tokyo, Japan.On leave from the Dept. of Astronomy, Cairo University, Cairo, Egypt.  相似文献   

Distance scaling of vertical and horizontal response spectra of the Loma Prieta earthquake     

Yousef Bozorgnia  Mansour Niazi 《地震工程与结构动力学》1993,22(8):695-707

Attenuations of the vertical and horizontal response spectra of the 17 October 1989 Loma Prieta, California, earthquake are developed through analyses of the ground motion at 53 sites within a 100 km radius of the source. The analyses are performed on the spectral ordinates for 16 incremental periods ranging from 0.05 to 2.0 sec. The response spectra are modelled empirically for two different site conditions characterized by rock and stiff-soil geologies. Data analysis is performed by the application of a non-linear multivariate regression procedure allowing for distance and site factor as independent variables. Variation of the vertical-to-horizontal (V/H) spectral ratios with wave frequency and distance shows the same behaviour as observed previously in the widely separated geographic regions of northeastern Taiwan and east-central Iran. The predicted ratios at sites underlain by stiff soil are generally higher than the commonly used value of 2/3 at high frequencies ( > 5 Hz) in the near-source region (R < 30 km), but reduce to 1/2 or less at longer periods and farther distances. This behaviour is also observed at rock sites; however, it is somewhat less pronounced. With a faster attenuation of spectral ordinates at higher frequencies, the shape of the response spectrum is found to change with distance. As expected, the spectral attenuation with distance is generally higher for the vertical spectrum than for the horizontal spectrum. The difference is particularly significant at the higher-frequency end of spectrum. Site amplification factors for stiff soil with respect to rock geology varies between 1.17 and 1.72 for horizontal spectrum and 1.01 and 1.81 for vertical spectrum. Spectral amplifications at four sites underlain by soft soil and artificial fill, are also evaluated. This is done by a comparison of the observed spectra with those predicted for rock geology at corresponding distances. As expected, the resulting amplification factors at soft-soil sites show significant increase relative to those at sites underlain by rock.  相似文献