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Progressive failure analysis of notched com..site plate by utilizing m..ro m..hanics approach

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Frontiers of Structural and Civil Engineering 2021年第3期15卷 623-642页

作者： Seyed m...GHOREISHI m..di FAKOOR Ahm.. azizi Faculty of New Sciences and Technologies University of TehranTehran***Iran Departm..t of m..hanical Engineering Science and Research BranchIslamic Azad UniversityTehran***Iran

In this study,gradual and sudden reduction m..hods were com..ned to sim..ate a progressive failure in notched com..site plates using a m..ro m..hanics *** the presented m..hod,a progressive failure is sim..ated based on a linear softening law prior to a catastrophic failure,and thereafter,sudden reduction m..hods are em..oyed for m..eling a progressive *** com..nation m..hod significantly reduces the com..tational cost and is also capable of sim..taneously predicting the first and last ply failures(LPFs)in com..site *** proposed m..hod is intended to predict the first ply failure(FPF),LPF,and dom..ant failure m..es of carbon/epoxy and glass/epoxy notched com..site *** addition,the effects of m..hanical properties and different stacking sequences on the propagation of dam..e in notched com..site plates were *** results of the presented m..hod were com..red with experim..tal data previously reported in the *** com..ring the num..ical and experim..tal data,it is revealed that the proposed m..hod can accurately sim..ate the failure propagation in notched com..site plates at a low com..tational cost.

关键词： progressive failure notched com..site plate Hashin failure criterion m..ro m..hanics approach finite elem..t m..hod

Size-dependent m..al interactions of a piezoelectrically lam..ated m..roarch resonator with 3:1 internal resonance

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Applied m..hem..ics and m..hanics(English Edition) 2020年第10期41卷 1517-1538页

作者： A.NIKPOURIAN m...GHAZAVI S.azizi m..hanical Engineering Departm..t Tarbiat Modares UniversityTehran 14115-111Iran m..hanical Engineering Departm..t Urmia University of TechnologyUrmia 57166-93187Iran

The nonlinear interactions of a m..roarch resonator with 3:1 internal resonance are *** m..roarch is subjected to a com..nation of direct current(DC)and alternating current(AC)electric *** piezoelectric layers are thoroughly bonded on the top and bottom..urfaces of the *** piezoelectric actuation is not only used to m..ulate the stiffness and resonance frequency of the resonator but also to provide the suitable linear frequency ratio for the activation of the internal *** size effect is incorporated by using the so-called m..ified strain gradient *** system..s highly nonlinear due to the co-existence of the initial curvature,the m..-plane stretching resulting from..lam..d anchors,and the electrostatic *** eigenvalue problem..s solved to conduct a frequency analysis and identify the possible regions for activating the internal *** effects of the piezoelectric actuation,the electric excitation,and the sm..l-scale effect are investigated on the internal *** nonlinear phenom..a such as Hopf bifurcation and hysteresis are identified in the m..roarch *** is shown that by applying appropriate piezoelectric actuation,one is able to activate m..roarch internal resonance regardless of the initial rise level of the *** is also disclosed that am..g all the param..ers,AC electric voltage has the greatest effect on the energy exchange between the interacting *** results can be used to design resonators and internal resonance based m..ro-electro-m..hanical system..Em..energy harvesters.

关键词： m..roarch resonator internal resonance m..tiple tim..scales m..hod m..ro-electro-m..hanical system..Em.. piezoelectric actuation electrostatic excitation

Effect of TiO2 loading on the m..phology and CO2/CH4 separation perform..ce of PEBAX-based m..branes

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Frontiers of Chem..al Science and Engineering 2019年第3期13卷 517-530页

作者： Navid azizi m..gan Isanejad Toraj m..am..di Reza m..Behbahani Research and Technology Center of m..brane Processes Chemical Engineering DepartmentIran University o f Science and Technology (IUST)NarmakTehranIran Gas Engineering Departm..t Petroleum University of TechnologyAhwazIran

m..branes have attracted m..h attention as econom..al m..hods for industrial chem..al processes. The effects of the titanium..ioxide nanoparticle load on the m..phology and CO2/CH4 separation perform..ce of poly (ether-block-am..e)(PEBAX-1657) m..ed m..rix m..branes (m..s) were investigated from..ressures of 3-12 bar and tem..ratures of 30℃-60℃. The PEBAX m..branes were characterized by scanning electron m..roscopy, Fourier transform..nfrared spectroscopy, X-ray diffraction, therm.. gravim..ric analysis, atom.. force m..roscopy and tensile strength analysis. The incorporation of TiO2 nanoparticles into the polym..ic m..s im..oved the CO2/CH4 gas separation perform..ce (both the perm..bility and selectivity) of the m..branes. The CO2 perm..bility and ideal CO2/CH4 selectivity values of the nanocom..site m..brane loaded with 8 wt-% TiO2 were 172.32 Barrer and 24.79, respectively whereas those of the neat m..brane were 129.87 Barrer and 21.39, respectively.

关键词： m..ed m..rix m..brane TiO2 nanoparticles PEBAX-1657 C02/CH4 separation

Effect of B vitam.. supplem..tation on plasm..hom..ysteine levels in celiac disease

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World Journal of Gastroenterology 2009年第8期15卷 955-960页

作者： m..am..d Hadithi Chris JJ m..der Frank Stam..oshan azizi J Bart A Crusius Am..o Salvador Pea Coen DA Stehouwer Yvo m..m..ders Departm..t of Gastroenterology VUmc University Medical Center Amsterdam PO Box 7057 Amsterdam 1007 MB The Netherlands Departm..t of Internal m..icine VUmc University Medical Center Amsterdam PO Box 7057 Amsterdam 1007 MB The Netherlands Laboratory of Im..nogenetics Department of Pathology VUmc University Medical Center Amsterdam PO Box 7057 Amsterdam 1007 MB The Netherlands Departm..t of Internal m..icine Academic Hospital Maastricht P. Debyelaan 25 6229 HX Maastricht The Netherlands

AIm..To investigate the effect of vitam.. supplem..ts on hom..ysteine levels in patients with celiac disease. m..HODS: Vitam.. B6, folate, vitam.. B12, and fasting plasm..hom..ysteine levels were m..sured in 51 consecutive adults with celiac disease [m..ian (range) age 56 (18-63) years; 40% m.., 26 (51%) had villous atrophy, and 25 (49%) used B-vitam.. supplem..ts] and 50 healthy control individuals m..ched for age and sex. Finally, the C677T polym..phism..f 5,10-m..hylene tetrahydrofolate reductase (m..FR) was evaluated in 46 patients with celiac disease and all control individuals. RESULTS: Patients with celiac disease and using vitam.. supplem..ts had higher serum..itam.. B6 (P = 0.003),folate (P m.. B12 (P = 0.012) levels than patients who did not or healthy controls (P = 0.035, P m.. B6, folate, and vitam.. B12, respectively). Lower plasm..hom..ysteine levels were found in patients using vitam.. supplem..ts than in patients who did not (P = 0.001) or healthy controls (P = 0.003). However, vitam.. B6 and folate, not vitam.. B12, were significantly and independently associated with hom..ysteine levels. Twenty-four (48%) of 50 controls and 23 (50%) of 46 patients with celiac disease carried the m..FR therm..abile variant T-allele (P = 0.89). CONCLUSION: Hom..ysteine levels are dependent on m..sh classification and the regular use of B-vitam.. supplem..ts is effective in reduction of hom..ysteine levels in patients with celiac disease and should be considered in disease m..agem..t.

关键词： Celiac disease Hom..ysteine Vitam.. supplem..ts

CFD m..eling of a spouted bed with a porous draft tube

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Particuology 2010年第5期8卷 415-424页

作者： Salar azizi Seyyed Hossein Hosseini m..oraveji Goodarz Ahm..i Chem..al Engineering Departm..t Faculty of EngineeringArak University Departm..t of Chem..al Engineering Faculty of EngineeringIlam University Departm..t of m..hanical and Aeronautical Engineering Clarkson University

Spouted bed with a porous draft tube is used for drying of grains and chem..al products and therm.. disinfestations process. This work provides a com..tational fluid dynam..s （CFD） sim..ation of binary m..tures of glass particles in a spouted bed with a porous draft tube. The sim..ation used the m..ti-fluid Eulerian-Eulerian approach based on kinetic theory of granular flows, incorporating a kinetic-frictional constitutive m..el for dense assem..ies of particulate solids and Gidaspow＇s drag m..el for the interaction between gas and particles. Influences of solids m..s fraction and inlet gas flow rate on pressure distribution, gas and particle velocities were studied. The m..eling results were com..red with the exper- im..tal work of Ishikura, Nagashim.. and Ide （2003） for the flow condition along the axis of the spouted bed. Good agreem..t between the m..eling results and experim..tal data was observed.

关键词： Spouted bedPorous dra tubeHydrodynam..sKinetictheoryCFD

An efficient correlation for calculating com..essibility factor of natural gases

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Journal of Natural Gas Chem..try 2010年第6期19卷 642-645页

作者： Navid azizi Dr.R.Behbahani Dr.m...Isazadeh Gas Engineering Departm..t Petroleum University of Technology

Com..essibility factor （z-factor） values of natural gases are necessary in m..t petroleum..ngineering *** arises when there are few available experim..tal data for the required com..sition,pressure and tem..rature *** of the m..t com..n m..hods of calculating z-factor values is em..rical ***,a new correlation based on the fam..s Standing-Katz （S-K） Chart is presented to predict z-factor *** advantage of this correlation is that it is explicit in z and thus does not require an iterative solution as is required by other ***,the com..rison between new one and other correlations is carried out and the results indicate the superiority of the new correlation over the other correlations used to calculate z-factor.

关键词： natural gas com..essibility factor explicit correlation

Num..ical evaluation of turbulence m..els for dense to dilute gas-solid flows in vertical conveyor

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Particuology 2012年第5期10卷 553-561页

作者： Salar azizi Dariush m..la Goodarz Ahm..i Chem..al Engineering Departm..t School of Chemical and Petroleum EngineeringShiraz UniversityShiraz 71345-1789Iran Departm..t of m..hanical and Aeronautical Engineering Clarkson UniversityPotsdamNY 13699-5725USA

A two-fluid m..el （TFm..ofm..tiphase flows based on the kinetic theory and sm..l frictional lim.. boundary condition of granular flow was used to study the behavior of dense to dilute gas-solid flows in vertical pneum..ic conveyor. An axisym..tric 2-dim..sional, vertical pipe with 5.6 m..ength and 0.01 m..nternal diam..er was chosen as the com..tation dom..n, sam..to that used for experim..tation in the literature. The chosen particles are spherical, of diam..er 1.91 m..and density 2500 kg/m.. Turbulence interaction between the gas and particle phases was investigated by Sim..in＇s and Ahm..i＇s m..els and their num..ical results were validated for dilute to dense conveying of particles. Flow regim.. transition and pressure drop were predicted. Voidage and velocity profiles of each phase were calculated in radial direction at different lengths of the conveying pipe. It was found that the voidage has a m..im.., and gas and solid velocities have m..im.. values along the center line of the conveying pipe and pressure drop has a m..im.. value in transition from..ense slugging to dilute stable flow regim.. Slug length and pressure fluctuation reduction were predicted with increasing gas velocity, too. It is shown that solid phase tur- bulence plays a significant role in num..ical prediction of hydrodynam..s of conveyor and the capability of particles turbulence m..els deDends on tuning param..ers of sliD-wall boundarv condition.

关键词： Vertical gas-solid flowTFm..netic theoryTurbulenceNum..ical m..eling

SIm..ATION OF VISCOELASTIC FLUID FLOWS IN EXPANSION GEOm..RY USING FINITE VOLUm..APPROACH

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Chinese Journal of Polym.. Science 2013年第12期31卷 1599-1612页

作者： m..teza azizi Ahm.. Ram..ani S.A Habib Etem..i m..hsan Shirzaei S Departm..t of Chem..al and Petroleum..ngineering Sharif University of Technology

The sim..ation results on viscoelastic fluid flows in sudden expansion geom..ry with different expansion ratios are presented. Oldroyd-B, linear Phan-Thien-Tanner （L-PTT） and Finitely Extensible Nonlinear Elastic （FENE-P） based constitutive equations were applied in two-dim..sional Cartesian coordinates. The governing equations in transient and fully developed regions were solved using open source software called OpenFOAm..The flow patterns, including velocity profiles, shear stresses and first norm.. stress differences in som..horizontal and vertical sections are illustrated. In addition, effects of the fluid type, flow dynam..s and expansion ratio on the flow and vortex patterns in transient and fully developed regions are presented and discussed. The presented results show that existences of vortices cause the inverse velocity and negative stresses in expansion regions of the channel which increase with increm..t of expansion ratio and Weissenberg num..r （We）. Furtherm..e, som..dead spaces can be observed at channel expansion regions close to the wall which are also increased. The results also show that at low We num..rs all fluids show close behavior while at high We num..rs the FENE-P fluid behavior shows high divergence from..hat of the two other fluids.

关键词： Expansion flow Sim..ation Finite Volume OpenFOAm Viscoelastic Fluids.

Determ..ing effective criteria for the selection of m.. industry locations in m..andaran Province: Application of AHP

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Forestry Studies in China 2013年第3期15卷 222-230页

作者： m..0} m..Am..ANZADEH Faculty of Natural Resources University of Tehran

Selecting the optim.. location with attention to conditions and restrictions is one of the m..t im..rtantfactors in establishing a m..ufacturing plant. Identification of effective criteria is an im..rtant stage in the selection for the location of industrial units. In this study, an analytic hierarchy process （AHP） was applied to select the m..t effective criteria for the location of m.. （m..ium..ensity fiberboard） industry in m..andaran Province, Iran. A consideration in ttaining this goal is that m..andaran is favored over other provinces because of its resources of raw lignocellulosic m.. erial required for wood and paper industries. The results indicate that the criterion of ＂m..erials and products＂ and the ub-criterion of ＂reliability of supply of raw m..erial＂ are the m..t im..rtant factors.

关键词： criterion AHP m.. industry selection of location m..andaran Province