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Journal of Mountain Science 2011年第2期8卷 124-130页

作者： Morteza AHMADI majid ESLAMI Department of Mining Engineering Tarbiat Modares University Ghaem Consulting Engineers

The stability of slopes is always of great concern in the field of rock engineering. The geometry and orientation of pre-existing discontinuities show a larger impact on the behavior of slopes that is often used to describe the measurement of the steepness, incline, gradient, or grade of a straight line. One of the structurally controlled modes of failure in jointed rock slopes is plane failure. There are numerous analytical methods for the rock slope stability including limit equilibrium, stress analysis and stereographic methods. The limiting equilibrium methods for slopes under various conditions against plane failure have been previously proposed by several investigators. However, these methods do not involve water pressure on sliding surfaces assessments due to water velocity and have not yet been validated by case study results. This paper has tried to explore the effects of forces due to water pressure on discontinuity surfaces in plane failure through applying the improved equations. It has studied the effect of water flow velocity on sliding surfaces in safety factor, as well. New equations for considering water velocity (fluid dynamics) are presented. To check the validity of the suggested equations, safety factor for a case study has been determined. Results show that velocity of water flow had significant effect on the amount of safety factor. Also, the suggested equations have higher validity rate compared to the current equations.

关键词： Plane Failure Limit Equilibrium Safety Factor Water Velocity

Development of a handheld diffuse optical breast cancer assessment probe

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Journal of Innovative Optical Health Sciences 2016年第2期9卷 31-40页

作者： majid Shokoufi Farid Golnaraghi School of Mechatronic Systems Engineering Simon Fraser University 250-13450102 Avenue SurreyCanadaBC V3T 0A3

Diffuse Optical Spectroscopy(DOS)is a promising non-invasive and non-ionizing technique for breast anomaly *** this study,we have developed a new handheld DOS probe to measure optical properties of breast *** the proposed probe,the breast tissue is illuminated with four near infrared(NIR)wavelengths light emitting diodes(LED),which are encapsulated in a package(eLEDs),and two PIN photodiodes measure the intensity of the scattered photons at two di®erent *** proposed technique of using eLEDs is introduced,in order to have a multi-wavelength pointed-beam illumination source instead of using the laser-coupledflberoptic technique,which increases the complexity,size,and cost of the *** the fact that the proposed technique miniaturizes the probe and reduces the complexity of the DOS,the study proves that it is accurate and reliable in measuring optical properties of the *** measurements are performed at the rate of 10 Hz which is suitable for dynamic measurement of biological activity,*** multi-spectral evaluation algorithm is used to reconstruct four main absorber concentrations in the breast including oxy-hemoglobin(cHb),deoxy-hemoglobin(cHbO_(2)),water(cH2O),fat(cFat),and average scattering coeficient of the medium,as well as concentration changes in Hb(cHb)and HbO_(2)(cHbO_(2)).Although the probe is designed for breast cancer diagnosis,it can be used in a wide range of applications for both static and dynamic measurements such as functional brain imaging.A series of phantoms,comprised of Delrinr,Intralipidr,PierceTM and Black ink,are used to verify performance of the *** probe will be tested on human subjects,in-vivo,in the next phase.

关键词： Breast cancer diffuse optical spectroscopy intrinsic optical contrast hemoglobin concentration optical breast phantom

Homogeneity analysis of streamflow records in arid and semi-arid regions of northwestern Iran

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Journal of Arid Land 2018年第4期10卷 493-506页

作者： majid KAZEMZADEH Arash MALEKIAN University of Tehran Karaj 31587-77871Iran

Homogeneity analysis of the streamflow time series is essential to hydrological modeling, water resources management and climate change studies. In this study, five absolute homogeneity tests and one clustering approach were used to determine the homogeneity status of the streamflow time series （over the period 1960-2010） in 14 hydrometric stations of three important basins （i.e., Aras River Basin, Urmia Lake Basin and Sefid-Roud Basin） in northwestern Iran. Results of the Buishand range test, yon Neumann ratio test, cumulative deviation test, standard normal homogeneity test and Pettitt test for monthly streamflow time series detected that about 42.26%, 38.09%, 33.33%, 39.28% and 68.45% of the streamflow time series were inhomogeneous at the 0.01 significance level, respectively. Streamflow time series of the stations located in the eastern parts of the study area or within the Urmia Lake Basin were mostly homogeneous. In contrast, streamflow time series in the stations of the Aras River Basin and Sefied-Roud Basin showed inhomogeneity at annual scales. Based on the overall classification for the monthly and annual streamflow series, we determined that about 45.60%, 11.53% and 42.85% of the time series were categorized into the ＇useful＇, ＇doubtful＇ and ＇suspect＇ classes according to the five absolute homogeneity tests. We also found the homogeneity patterns of the streamflow time series by using the clustering approach. The results suggested the effectiveness of the clustering approach for homogeneity analysis of the streamflow time series in addition to the absolute homogeneity tests. Moreover, results of the absolute homogeneity tests and clustering approach indicated obvious decreasing change points of the streamflow time series in the 1990s over the three basins, which were mostly related to the hydrological droughts.

关键词： streamflow time series homogeneity test clustering analysis inhomogeneity Urmia Lake northwestern Iran

Isomorphisms of Finite Semi-Cayley Graphs

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Acta Mathematica Sinica,English Series 2015年第4期31卷 715-730页

作者： majid AREZOOMAND Bijan TAERI Department of Mathematical Sciences Isfahan University of Technology

Let G be a finite group. A Cayley graph over G is a simple graph whose automorphism group has a regular subgroup isomorphic to G. A Cayley graph is called a CI-graph （Cayley iso- morphism） if its isomorphic images are induced by automorphisms of G. A well-known result of Babai states that a Cayley graph F of G is a CI-graph if and only if all regular subgroups of Aut（F） isomorphic to G are conjugate in Aut（F）. A semi-Cayley graph （also called bi-Cayley graph by some authors） over G is a simple graph whose automorphism group has a semiregular subgroup isomorphic to G with two orbits （of equal size）. In this paper, we introduce the concept of SCI-graph （semi-Cayley isomorphism） and prove a Babai type theorem for semi-Cayley graphs. We prove that every semi-Cayley graph of a finite group G is an SCI-graph if and only if G is cyclic of order 3. Also, we study the isomorphism problem of a special class of semi-Cayley graphs.

关键词： Semi-Cayley graph Cayley graph CI-graph semiregular subgroup

Evaluating estimated sediment delivery by Revised Universal Soil Loss Equation(RUSLE)and Sediment Delivery Distributed(SEDD)in the Talar Watershed,Iran

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Frontiers of Earth Science 2020年第1期14卷 50-62页

作者： Mohammad Saeid MIRAKHORLO majid RAHIMZADEGAN Department of Water Resources Faculty of Civil EngineeringK.N.Toosi University of TechnologyTehranIran

The performance of the Revised Universal Soil Loss Equation(RUSLE)as the most widely used soil erosion model is a challenging ***,the objective of this study is investigating the estimated sediment delivery by the RUSLE method and Sediment Delivery Distributed(SEDD)*** this end,the Talar watershed in Iran was selected as the study ***,700 paired sediment-discharge measurements at Valikbon and Shirgah-Talar hydrometric stations between the years 1991 and 2011 were collected and used in sediment rating *** procedures were investigated to produce the required RUSLE *** estimated soil erosion by RUSLE was evaluated using sediment rating curve data by two methods including least squares and quantile *** average annual suspended sediment load was calculated for each sub-watershed of the study area using the SEDD ***,a sediment rating curve was estimated by least squares and quantile regression methods using paired discharge-sediment *** average annual suspended sediment load values were calculated for two hydrometric stations and were further evaluated by the SEDD *** results indicated that the first considered procedure,which utilized 15-min rainfall measurements for the rainfall factor(R),and the classification method of SENTINEL-2 MSI image for the cover management factor(C),offered the best results in producing RUSLE ***,the results revealed the advantages of utilizing satellite images in producing cover management layer,which is required in the RUSLE method.

关键词： Revised Universal Soil Loss Equation(RUSLE) sediment rating curve quantile regression Geographic Information System(GIS)

Perturbation,symmetry analysis,Bäcklund and reciprocal transformation for the extended Boussinesq equation in fluid mechanics

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Communications in Theoretical Physics 2021年第4期73卷 21-28页

作者： Gangwei Wang Abdul-majid Wazwaz School of Mathematics and Statistics Hebei University of Economics and BusinessShijiazhuang050061China Department of Mathematics Saint Xavier UniversityChicagoIL 60655United States of America

In this work,we study a generalized double dispersion Boussinesq equation that plays a significant role in fluid mechanics,scientific fields,and ocean *** equation will be reduced to the Korteweg-de Vries equation via using the perturbation *** derive the corresponding vectors,symmetry reduction and explicit solutions for this *** readily obtain Bäcklund transformation associated with truncated Painlevé*** also examine the related conservation laws of this equation via using the multiplier ***,we investigate the reciprocal Bäcklund transformations of the derived conservation laws for the first time.

关键词： Boussinesq equation perturbation and symmetry analysis Bäcklund transformation conservation laws

Evaluation of Ordinary Least Square(OLS) and Geographically Weighted Regression(GWR) for Water Quality Monitoring:A Case Study for the Estimation of Salinity

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Journal of Ocean University of China 2018年第2期17卷 305-310页

作者： NAZEER majid BILAL Muhammad Earth & Atmospheric Remote Sensing Laboratory (EARL) Department of Meteorology COMSATS Institute of Information Technology School of Marine Sciences Nanjing University of Information Science and Technology Department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic University

Landsat-5 Thematic Mapper(TM) dataset have been used to estimate salinity in the coastal area of Hong Kong. Four adjacent Landsat TM images were used in this study, which was atmospherically corrected using the Second Simulation of the Satellite Signal in the Solar Spectrum(6S) radiative transfer code. The atmospherically corrected images were further used to develop models for salinity using Ordinary Least Square(OLS) regression and Geographically Weighted Regression(GWR) based on in situ data of October 2009. Results show that the coefficient of determination(R^2) of 0.42 between the OLS estimated and in situ measured salinity is much lower than that of the GWR model, which is two times higher(R^2 = 0.86). It indicates that the GWR model has more ability than the OLS regression model to predict salinity and show its spatial heterogeneity better. It was observed that the salinity was high in Deep Bay(north-western part of Hong Kong) which might be due to the industrial waste disposal, whereas the salinity was estimated to be constant(32 practical salinity units) towards the open sea.

关键词： Landsat Thematic Mapper water quality salinity remote sensing coastal water

Synthesis of nanocrystalline γ-Al_2O_3 by sol-gel and precipitation methods for methanol dehydration to dimethyl ether

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Journal of Natural Gas Chemistry 2011年第2期20卷 128-134页

作者： Zahra Hosseini majid Taghizadeh Fereydoon Yaripour Chemical Engineering Department Babol University of Technology Catalyst Research Group Petrochemical Research and Technology Company NPC

The capability of sol-gel and conventional precipitation techniques for the synthesis of nanocrystalline γ-alumina was investigated. These catalysts were used for vapor-phase dehydration of methanol to dimethyl ether in a fixed-bed reactor under the same operating conditions （T = 300 ？C, P = 1 bar, LHSV = 2.8, 11.7, 26.1 h？1） and characterized by means of N2 adsorption-desorption, NH3-TPD, XRD, TGA and SEM techniques. According to the experimental results, the catalysts prepared using sol-gel method in non-aqueous medium showed better performance compared with those prepared by other methods.

关键词： γ-Al2O3 sol-gel precipitation methanol dehydration dimethyl ether

CFD-DEM simulation of the hole cleaning process in a deviated well drilling： The effects of particle shape

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Particuology 2016年第2期14卷 72-82页

作者： Siamak Akhshik Mehdi Behzad majid Rajabi Department of Mechanical Engineering Sharif University of Technology Azadi Avenue Tehran Iran School of Mechanical Engineering lran University of Science and Technology Narmak Tehran Iran

We investigate the effect of particle shape on the transportation mechanism in well-drilling using a three-dimensional model that couples computational fluid dynamics （CFD） with the discrete element method （DEM）. This numerical method allows us to incorporate the fluid-particle interactions （drag force, contact force, Saffman lift force, Magnus lift force, buoyancy force） using momentum exchange and the non-Newtonian behavior of the fluid. The interactions of particle-particle, particle-wall, and particle-drill pipe are taken into account with the Hertz-Mindlin model. We compare the transport of spheres with non-spherical particles （non-smooth sphere, disc, and cubic） constructed via the multi- sphere method for a range of fluid inlet velocities and drill pipe inclination angles. The simulations are carried out for laboratory-scale drilling configurations. Our results demonstrate good agreement with published experimental data. We evaluate the fluid-particle flow patterns, the particle velocities, and the particle concentration profiles. The results reveal that particle sphericity plays a major role in the fluid-solid interaction. The traditional assumption of an ideal spherical particle may cause inaccurate results.

关键词： CFD-DEM method Deviated well drilling Particles transport Two-way coupling scheme Particle-fluid Interaction

Spin and pseudospin symmetric Dirac particles in the field of Tietz-Hua potential including Coulomb tensor interaction

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Chinese Physics B 2013年第9期22卷 233-244页

作者： Sameer M. Ikhdair majid Hamzavi Department of Physics Faculty of ScienceAn-Najah National UniversityNew CampusJunaidNablusWest BankPalestine Department of Electrical and Electronic Engineering Near East University Department of Science and Engineering Abhar BranchIslamic Azad University

Approximate analytical solutions of the Dirac equation for Tietz-Hua （TH） potential including Coulomb-like tensor （CLT） potential with arbitrary spin-orbit quantum number K are obtained within the Pekeris approximation scheme to deal with the spin-orbit coupling terms K（K± 1）r^-2. Under the exact spin and pseudospin symmetric limitation, bound state energy eigenvalues and associated unnormalized two-component wave functions of the Dirac particle in the field of both attractive and repulsive TH potential with tensor potential are found using the parametric Nikiforov-Uvarov （NU） method. The cases of the Morse oscillator with tensor potential, the generalized Morse oscillator with tensor potential, and the non-relativistic limits have been investigated.

关键词： Dirac equation Tietz-Hua (TH) potential Coulomb-like tensor (CLT) potential generalizedMorse potential