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Cube-octameric silsesquioxane (POSS)-capped magnetic iron oxide nanoparticles for the efficient removal of methylene blue

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Frontiers of Chemical Science and Engineering 2019年第3期13卷 563-573页

作者： ali Akbari Nasser Arsalani Bagher eftekhari-Sis Mojtaba Amini Gholamreza Gohari Esmaiel Jabbari Department of Chemistry Faculty of ScienceUniversity of MaraghehMaraghehIran Research Laboratory of Polymer Department of Organic and BiochemistryFaculty of ChemistryUniversity of TabrizTabrizIran Department of Horticulture Faculty of AgricultureUniversity of MaraghehMaraghehIran Department of Chemical Engineering University of South CarolinaColumbiaSC 29208USA

Octavinyl polyhedral oligomeric silsesquioxane (POSS) was polymerized on the surface of Fe3O4 nanoparticles (NPs) and then the NPs were functionalized with carboxylic acid groups using thiol-ene click reactions with thioglycolic *** as-prepared Fe3O4@POSS-COOH magnetic hybrid NPs had mesoporous structures with an average particle diameter of 15 nm and a relatively high specific surface area of 447 m^2· g^-*** results showed that 4 mg of Fe3O4@POSS-COOH NPs efficiently adsorbed and removed methylene blue from water at 5 *** is due to the presence of both carboxylic acid and pendant vinyl groups on the Fe3O4@POSS-COOH *** NPs could be easily withdrawn from water within a few seconds under moderate magnetic field and showed high stability in acid and alkaline aqueous mediums.

关键词： nanomagnetic POSS surface polymerization thiol-ene reaction adsorbent water treatment

Mechanism Based Pharmacokinetic Pharmacodynamic Modeling of Vildagliptin as an Add-on to Metformin for Subjects with Type 2 Diabetes

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Computer Modeling in Engineering & Sciences 2018年第2期114卷 153-171页

作者： Marziyeh eftekhari Omid Vahidi School of Chemical Petroleum and Gas EngineeringIran University of Science and TechnologyNarmakTehranIran

Various drugs are used to maintain normoglycemia in subjects with type 2 diabetes *** combination of the drugs from different classes in one single tablet may enhance the effectiveness of the anti-diabetic *** investigate the impact of combining drugs on the glucose regulation of subjects with type 2 diabetes,we propose a pharmacokinetic/pharmacodynamics(PK/PD)mathematical modeling approach for a combination of metformin and vildagliptin *** the proposed modeling approach,two separate PK models representing oral administration of metformin and vildagliptin for diabetic subjects are interconnected to a PD model comprising a detailed compartmental physiological model representing the regulatory effect of insulin,incretins and glucagon hormones on glucose concentration in a human *** impact of doses of individual drugs and their combination on the blood glucose concentration of a group of type 2 diabetic subjects is *** is indicated that while administration of individual drugs reduces the blood glucose levels,since they have separate mechanisms of action,combining them synergizes lowering the blood glucose levels.

关键词： Pharmacokinetics pharmacodynamics mathematical modeling anti-diabetic drugs metformin vildagliptin

Prediction of mode I fracture toughness of rock using linear multiple regression and gene expression programming

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第5期14卷 1421-1432页

作者： Bijan Afrasiabian Mosleh eftekhari Department of Mining Engineering Science and Research BranchIslamic Azad UniversityTehranIran Department of Mining Engineering Faculty of EngineeringTarbiat Modares UniversityTehranIran

Prediction of mode I fracture toughness(KIC) of rock is of significant importance in rock engineering analyses. In this study, linear multiple regression(LMR) and gene expression programming(GEP)methods were used to provide a reliable relationship to determine mode I fracture toughness of rock. The presented model was developed based on 60 datasets taken from the previous literature. To predict fracture parameters, three mechanical parameters of rock mass including uniaxial compressive strength(UCS), Brazilian tensile strength(BTS), and elastic modulus(E) have been selected as the input parameters. A cluster of data was collected and divided into two random groups of training and testing ***, different statistical linear and artificial intelligence based nonlinear analyses were conducted on the training data to provide a reliable prediction model of KIC. These two predictive methods were then evaluated based on the testing data. To evaluate the efficiency of the proposed models for predicting the mode I fracture toughness of rock, various statistical indices including coefficient of determination(R2),root mean square error(RMSE), and mean absolute error(MAE) were utilized herein. In the case of testing datasets, the values of R2, RMSE, and MAE for the GEP model were 0.87, 0.188, and 0.156,respectively, while they were 0.74, 0.473, and 0.223, respectively, for the LMR model. The results indicated that the selected GEP model delivered superior performance with a higher R2value and lower errors.

关键词： Mode I fracture Toughness Critical stress intensity factor Linear multiple regression(LMR) Gene expression programming(GEP)

Quantum Correlations in Ising-XYZ Diamond Chain Structure under an External Magnetic Field

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Chinese Physics Letters 2015年第10期32卷 9-13页

作者： Faizi E. eftekhari H. Department of Physics Azerbaijan Shahid Madani University

We consider an entangled Ising-XY Z diamond chain structure. Quantum correlations for this model are inves- tigated by using quantum discord and trace distance discord. Quantum correlations are obtained for different values of the anisotropy parameter, magnetic field and temperature. By comparison between quantum correlations, we show that the trace distance discord is always larger than quantum discord. Finally, some novel effects such as increasing the quantum correlations with temperature and constructive role of anisotropy parameter, which may play to the quantum correlations, are observed.

关键词： TDD Quantum Correlations in Ising-XYZ Diamond Chain Structure under an External Magnetic Field

Application assessment of GRACE and CHIRPS data in the Google Earth Engine to investigate their relation with groundwater resource changes (Northwestern region of Iran)

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Journal of Groundwater Science and Engineering 2021年第2期9卷 102-113页

作者： Afraz Mehdi eftekhari Mobin Akbari Mohammad ali Haji Elyasi Noghani Zahra Forests Range and Watershed Management OrganizationTehranIran Young Researchers and Elite Club Mashhad BranchIslamic Azad UniversityMashhadIran Department of Civil Engineering University of BirjandBirjandIran K.N.Toosi University of Technology TehranIran Master Research Institute of Forest and Rangeland TehranIran

In recent years,drought has become a global issue,especially in arid and semi-arid *** is without doubt that the identification and monitoring of the drought phenomenon can help to reduce the damages that would *** addition,rain is one of the factors which directly affect the water levels of underground water *** research applied a linear gradient regression method developed on the basis of GRACE,CHIRPS,and data from monitoring wells to investigate the groundwater storage *** data have been analyzed on the Google Earth Engine *** order to conduct temporal and spatial analyses,the water levels of the aquifer were generated from the monitoring wells and zoned into five ***,the amount of water storage and rain from the year 2003 to 2017 in the West Azerbaijan Province were investigated using the GRACE satellite and the CHIRPS data,*** results obtained from the GRACE satellite data show that the average water level in the underground reservoirs in Iran had started to decrease since 2008 and reached its peak in 2016 with an average decrease of 16 cm in that *** average annual decline of groundwater level in the studied time period was 5 cm.A chart developed from the CHIRPS annual rainfall data indicates that the biggest decline in rainfall occurred in 2008,and the declining trend has remained *** analyses were made on GRACE with CHIRPS results and monitoring wells data separately,from which the correlation coefficients are between 86% and 97%,showing generally high ***,the results obtained from the zoning of the aquifer showed that in the period of 2004 to 2016,due to the decrease in rainfall and the excessive withdrawal of groundwater,the water levels also decreased.

关键词： GRACE Groundwater storage CHIRPS Middle East region

Magnetic field effects on the nonlinear vibration of a rotor

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Applied Mathematics and Mechanics(English Edition) 2020年第2期41卷 289-312页

作者： M.eftekhari A.DASHTI-RAHMATABADI A.MAZIDI Department of Mechanical Engineering Yazd UniversityYazd 89195-741Iran

The nonlinear vibration of a rotor operated in a magnetic field with geometric and inertia nonlinearity is investigated. An asymmetric magnetic flux density is generated,resulting in the production of a load on the rotor since the air-gap distribution between the rotor and the stator is not uniform. This electromagnetic load is a nonlinear function of the distance between the geometric centers of the rotor and the stator. The nonlinear equation of motion is obtained by the inclusion of the nonlinearity in the inertia, the curvature, and the electromagnetic load. After discretization of the governing partial differential equations by the Galerkin method, the multiple-scale perturbation method is used to derive the approximate solutions to the equations. In the numerical results, the effects of the electromagnetic parameter load, the damping coefficient, the amplitude of the initial displacement, the mass moment of inertia, and the rotation speed on the linear and nonlinear backward and forward frequencies are investigated. The results show that the magnetic field has significant effects on the nonlinear frequency of oscillation.

关键词： nonlinear vibration in-extensional rotor nonlinear curvature gyroscopic effect magnetic field

Mixed finite element and differential quadrature method for free and forced vibration and buckling analysis of rectangular plates

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Applied Mathematics and Mechanics(English Edition) 2012年第1期33卷 81-98页

作者： S. A. eftekhari A. A. JAFARI Department of Mechanical Engineering K. N. Toosi University of Technology

This paper presents a combined application of the finite element method （FEM） and the differential quadrature method （DQM） to vibration and buckling problems of rectangular plates. The proposed scheme combines the geometry flexibility of the FEM and the high accuracy and efficiency of the DQM. The accuracy of the present method is demonstrated by comparing the obtained results with those available in the literature. It is shown that highly accurate results can be obtained by using a small number of finite elements and DQM sample points. The proposed method is suitable for the problems considered due to its simplicity and potential for further development.

关键词： finite element method (FEM) differential quadrature method (DQM) rectangular plate free and forced vibration buckling analysis

Texture evolution and mechanical anisotropy of an ultrafine/nano-grained pure copper tube processed via hydrostatic tube cyclic expansion extrusion

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International Journal of Minerals,Metallurgy and Materials 2022年第12期29卷 2241-2251页

作者： Seyed Moien Faregh Ghader Faraji Mahmoud Mosavi Mashhadi Mohammad eftekhari School of Mechanical Engineering College of EngineeringUniversity of TehranTehran 11155-4563Iran

Texture evolution and mechanical anisotropic behavior of an ultrafine-grained(UFG)pure copper tube processed by recently introduced method of hydrostatic tube cyclic expansion extrusion(HTCEE)was *** the UFG tube,different deformation behavior and a significant anisotropy in tensile properties were recorded along the longitudinal and peripheral *** HTCEE process increased the yield strength and the ultimate strength in the axial direction by 3.6 and 1.67 times,***,this process increased the yield strength and the ultimate strength in the peripheral direction by 1.15 and 1.12 times,*** ratio of ultimate tensile strength in the peripheral direction to that in the axial direction,as a criterion for mechanical anisotropy,are 1.7 and 1.16 for the as-annealed coarse-grained and the HTCEE processed UFG tube,*** results are indicative of a reducing effect of the HTCEE process on the mechanical ***,after HTCEE process,a low loss of ductility was observed in both directions,which is another advantage of HTCEE *** measurements revealed a slight increment of hardness values in the peripheral direction,which is in agreement with the trend of tensile *** analysis was conducted in order to determine the oriental distribution of the *** obtained{111}pole figures demonstrate the texture evolution and reaffirm the anisotropy observed in mechanical *** electron microscopy micrographs showed that different modes of fracture occurred after tensile testing in the two orthogonal directions.

关键词： severe plastic deformation ultrafine grained hydrostatic tube cyclic expansion extrusion anisotropy texture

Leishmaniosis phytotherapy: Review of plants used in Iranian traditional medicine on leishmaniasis

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Asian Pacific Journal of Tropical Biomedicine 2015年第9期5卷 673-679页

作者： Mahmoud Bahmani Kourosh Saki Behrouz Ezatpour Somayeh Shahsavari Zohreh eftekhari Mahyar Jelodari Mahmoud Rafieian Kopaei reza Sepahvand Food and Beverages Safety Research Center Urmia University of Medical Sciences Shahid Beheshti University of Medical Sciences Razi Herbal Medicines Research Center Lorestan University of Medical Sciences Young Researchers and Elite Club Khorramabad Branch Islamic Azad University Research and Production Complex Pasture Institute of Iran Faculty of Veterinary Medicine Urmia University Medical Plants Research Center Shahrekord University of Medical Sciences

Many native plants in traditional medicine have been used for the treatment of cutaneous leishmaniasis and the recent clinical trials have proven the efficacy of some of them. Researches conducted on these plants have shown that garlic, shallots, wormwood, yarrow, walnuts, thyme, henna plant, mimosa, aloe, wood betony, medlar, periwinkle, yeah, savory, black beans, etc. are ef ective on cutaneous leishmania. Synthetic agents in Iranian market have some disadvantages such as high cost and side ef ects and are painful in injections. Given the ef ectiveness of these plants, they can be a source of natural and safe compounds for the treatment of Leishmania. Therefore, more clinical researches should be done to determine the ef ectiveness and safety of these medicinal plants, their active ingredients and their possible toxic substances which can lead to the production of ef ective and safe drugs for leishmaniasis. It also might be an ef ective way to prepare herbal ointment on wound healing.

关键词： Leishmania Leishmaniasis Native medicinal plants Iran