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几何形状对气垫升力的影响研究

哈尔滨工程大学学报（英文版） 2024年第1期23卷 74-84页

作者： Hamed Petoft vahid fakhari Abbas Rahi Faculty of Mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

One of the crucial and challenging issues for researchers is presenting an appropriate approach to evaluate the aerodynamic characteristics of air cushion vehicles(ACVs)in terms of system design *** of these issues includes introducing a suitable approach to analyze the effect of geometric shapes on the aerodynamic characteristics of *** main novelty of this paper lies in presenting an innovative method to study the geometric shape effect on air cushion lift force,which has not been investigated thus ***,this paper introduces a new approximate mathematical formula for calculating the air cushion lift force in terms of parameters,including the air gap,lateral gaps,air inlet velocity,and scaling factor for the first ***,we calculate the aerodynamic lift force applied to nine different shapes of the air cushions used in the ACVs in the present paper through the ANSYS Fluent *** geometrical shapes studied in this paper are rectangular,square,equilateral triangle,circular,elliptic shapes,and four other combined shapes,including circle-rectangle,circle-square,hexagonal,and fillet *** showed that the cushion with a circular pattern produces the highest lift force among other geometric shapes with the same *** increase in the cushion lift force can be attributed to the fillet with a square shape and its increasing radius compared with the square shape.

关键词： Lift force Air cushion vehicle Geometric shape Simulation Gap Inlet velocity Scaling factor

Unwanted disorders and xenogeneic graft-versus-host disease in experimental immunodeficient mice:How to evaluate and how to report

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Animal Models and Experimental Medicine 2025年第1期8卷 20-29页

作者： Seyed Mostafa Monzavi Samad Muhammadnejad vahid Mansouri Hami Ashraf Naser Ahmadbeigi Gene Therapy Research Center Digestive Diseases Research InstituteTehran University of Medical SciencesTehranIran INSERM U981 Institut Gustave RoussyVillejuifFrance Chronic Respiratory Diseases Research Center National Research Institute of Tuberculosis and Lung Diseases(NRITLD)Shahid Beheshti University of Medical SciencesTehranIran

Human-derived tumor models are essential for preclinical development of new anti-cancer drug *** animal models bearing tumors of human origin,such as patient-derived or cell line-derived xenograft tumors,is dependent on immuno-deficient ***-bearing immunodeficient mice are susceptible to develop-ing unwanted disorders primarily irrelevant to the tumor nature;and if get involved with such disorders,reliability of the study results will be undermined,inevitably con-founding the research in ***,a rigorous health surveillance and clinical monitoring system,along with the establishment of a strictly controlled barrier facility to maintain a pathogen-free state,are *** if all pathogen control and biosafety measures are followed,there are various noninfectious disorders capable of causing tissue and multiorgan damage in immunodeficient ***,the re-searchers should be aware of sentinel signs to carefully monitor and impartially report *** review discusses clinical signs of common unwanted disorders in experi-mental immunodeficient mice,and how to examine and report them.

关键词： animal models graft-versus-host disease health surveillance preclinical drug evaluation xenograft model antitumor assays

Finite element analysis of controlled low strength materials

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Frontiers of Structural and Civil Engineering 2019年第5期13卷 1243-1250页

作者： vahid ALIZADEH Gildart Haase School of Computer Sciences & Engineering Fairleigh Dickinson UniversityTeaneckNJ 07666USA

Controlled low strength materials (CLSM) are flowable and self-compacting construction materials that have been used in a wide variety of applications. This paper describes the numerical modeling of CLSM fills with finite element method under compression loading and the bond performance of CLSM and steel rebar under pullout loading. The study was conducted using a plastic-damage model which captures the material behavior using both classical theory of elasto-plasticity and continuum damage mechanics. The capability of the finite element approach for the analysis of CLSM fills was assessed by a comparison with the experimental results from a laboratory compression test on CLSM cylinders and pullout tests. The analysis show's that the behavior of a CLSM fill w'hile subject to a failure compression load or pullout tension load can be simulated in a reasonably accurate manner.

关键词： CLSM finite element method compressive strength pullout numerical modeling plastic damage model

Experimental and modeling study of the kinetics of methane hydrate formation and dissociation

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Chinese Journal of Chemical Engineering 2021年第1期34卷 365-374页

作者： Vafa Feyzi vahid Mohebbi Ahvaz Petroleum Faculty Petroleum University of Technology(PUT)AhvazIran

In this work,several experiments were conducted at isobaric and isothermal condition in a CSTR reactor to study the kinetics of methane hydrate formation and *** were performed at five temperatures and three pressure levels(corresponding to equilibrium pressure).Methane hydrate formation and dissociation rates were modeled using mass transfer limited kinetic models and mass transfer coefficients for both formation and dissociation were *** of results,shows that mass transfer coefficients for methane hydrate dissociation are one order greater than formation *** transfer coefficients were correlated by polynomials as relations of pressure and *** results and the method can be applied for prediction of methane production from naturally occurring methane hydrate deposits.

关键词： Methane hydrate Kinetics Formation Dissociation Mass transfer

Dynamic analysis of the composite laminated repaired perforated plates by using multi-patch IGA method

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Chinese Journal of Aeronautics 2021年第1期34卷 266-280页

作者： Jamshid FAZILATI vahid KHALAFI Aeronautical Science and Technology Department Aerospace Research InstituteTehran 14657-74111Iran Aerospace Engineering Department Shahid Sattari Aeronautical University of Science and TechnologyTehranIran

The bonded repair techniques seem to be the most frequent procedures in the aviation *** achieved composite repaired perforated thin-walled plate is a complex geometry with high numerical analysis *** NURBS-based Isogeometric Analysis(IGA)proposes a sensible and affordable tool to carry out such geometry *** this context,a well-known technique is to divide the original geometry assembly into number of simple neighbors connected *** the present study the free vibration analysis of the perforated plates repaired on one side with an external bonded composite laminated patch is investigated.A multi-patch geometry modeling approach is implemented in line with the first order shear deformation theory of *** order to hold the geometry integrity and uniformity,all the degrees of freedom between adjacent geometry patches are completely tied through implementing a Nitsche *** show the effectiveness and accuracy of the developed formulation,some representative results are extracted and compared with those from *** effects of geometrical as well as material parameters including boundary condition,cutout shape,and repair layup on the dynamic response of the repaired perforated plates are then investigated.

关键词： Composite laminate Perforated plate Bonded repair Isogeometric analysis(IGA) Multi-patch model

Ocean Chemistry Revealed by Mineralogical and Geochemical Evidence at the Permian——Triassic Mass Extinction,Offshore the Persian Gulf,Iran

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Acta Geologica Sinica(English Edition) 2016年第5期90卷 1852-1864页

作者： vahid TAVAKOLI School of Geology College of ScienceUniversity of Tehran

The Upper Permian Dalan Formation and the Lower Triassic Kangan Formation in the Persian Gulf area are mainly composed of shallow marine facies limestone and *** subsurface-cored intervals were investigated in order to understand the original mineralogy and paleoceanic *** decreasing trend of Sr concentration in these deposits shows that aragonite was precipitated during the Late Permian and then gradually changed to calcite toward the Permian-Triassic boundary（PTB）.The dissolution rate of aragonite decreased from 60 m below the PTB toward the boundary,with the only exception at 10 m below the Permian-Triassic Boundary（PTB） due to the Permian-Triassic unconformity in this *** increasing trend of Mg/Ca ratio in a global scale at the end-Permian time shows that the interpreted variation of mineralogy does not result from the change of this *** increasing p（CO2） and decreasing pH are considered to be the main controlling *** increase of Ca2＋ at the end-Permian time due to the input of meteoric waters is too little to fully compensate this effect.A local maximum of the Si content just at the PTB confirms the input of runoff waters.

关键词： Permian Triassic carbonate mineralogy elemental composition Iran Persian Gulf

Effects of foundation rocking and uplifting on displacement amplification factor

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Earthquake Engineering and Engineering Vibration 2018年第3期17卷 511-525页

作者： Mohammad Khanmohammadi vahid Mohsenzadeh School of Civil Engineering University of Tehran Department of Civil Engineering Mc Master University

Prediction of displacement demand to assess seismic performance of structures is a necessary step where nonlinear static procedures are *** such predictions have been well established in literature for fixed-base structures,fewer bodies of researches have been carried out on the effect of rocking and uplifting of shallow foundations supported by soil,on such *** paper aimed to investigate the effect of soil structure interaction on displacement amplification factor C1 using the beam on nonlinear Winkler foundation concept.A practical range of natural period,force reduction factors,and wide range of anticipated behavior from rocking,uplifting and hinging are considered and using thousands nonlinear time history analysis,displacement amplification factors are *** results indicate that the suggested equations in current rehabilitation documents underestimate displacement demands in the presence of foundation rocking and ***,using regression analyses,new equations are proposed to estimate mean values of C1.

关键词： soil-structure interaction rocking and uplifting foundations displacement amplification factor

Dielectric microspheres enhance microscopy resolution mainly due to increasing the effective numerical aperture

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Light(Science & Applications) 2023年第1期12卷 17-19页

作者： Arash Darafsheh vahid Abbasian Department of Radiation Oncology Washington University School of Medicine in St.LouisSt.LouisMO 63110USA

Microsphere-assisted microscopy utilizing a microsphere in immediate proximity of the specimen boosts the imaging resolution mainly as a result of an increase in the effective numerical aperture of the system.

关键词： resolution numerical utilizing

Mechanical Properties and Microstructure Evolution of AA1100 Aluminum Sheet Processed by Accumulative Press Bonding Process

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Acta Metallurgica Sinica(English Letters) 2016年第8期29卷 735-741页

作者： Amir Mostafapor vahid Mohammadinia Department of Mechanical Engineering University of Tabriz Department of Mechanical Engineering University of Maragheh

Accumulative press bonding（APB） is a novel variant of severe plastic deformation processes,which is devised to produce materials with ultra-fine *** the present work,the mechanical properties and microstructural evolution of AA1100 alloy,which is produced by APB technique,were *** study of the microstructure of AA1100 alloy was performed by optical *** results revealed that the grain size of the samples decreased to 950 nm after six passes of APB *** yield strength of AA1100 alloy after six passes of the process increased up to 264 MPa,which is three times higher than that of the as-cast material（89 MPa）.After six passes,microhardness values of AA1100 alloy increased from 38 to 61 ***,the results showed that the behavior of variations in mechanical properties is in accordance with the microstructural changes and it can be justified by using the Hall-Patch ***,the rise in the yield strength can be attributed to the reduction in the grain size leading to the strain hardening.

关键词： Severe plastic deformation Accumulative press bonding Mechanical properties Metallurgical properties AA1100 alloy