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Nano TiO_2 as a heterogeneous catalyst in an efficient one-pot three-component mannich synthesis of β-aminocarbonyls

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Chinese Chemical Letters 2011年第10期22卷 1203-1206页

作者： m.Z.Kassaee Reza mohammadi Hassan masrouri Farnaz movahedi Department of Chemistry Tarbiat Modares UniversityP.O.Box 14155-4838TehranIran

TiO_2 nanoparticles（TiO_2 NPs） worked as an efficient heterogeneous catalyst in a one-pot,three-component,and solvent free mannich reaction;producing variousβ-aminocarbonyls in good yields,and with good *** catalyst was easily separated from the reaction mixture and was recycled four times with no significant loss of its catalytic activity.

关键词： TiO_2 nanoparticles Heterogeneous catalyst mannich reaction β-Aminocarbonyls Solvent-free

Design aspect of a novel L-shaped pulsed column for liquid–liquid extraction applications: Energy consumption and the characteristics velocity concept

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Chinese Journal of Chemical Engineering 2018年第4期26卷 723-730页

作者： Pouria Amani Elham mohammadi Sahar Akhgar School of Chemical Engineering College of Engineering University of Tehran Chemical Engineering Department Tarbiat Modares University

This article deals with the evaluation of the consumption of energy for a steady state solvent extraction in a novel L-shaped pulsed sieve-plate column, which is highly required for design and optimization of the periodic flow processes for industrial applications. In this regard, a comprehensive evaluation on the energy consumption in case of a pulsed flow for three different chemical systems is conducted and besides the influence of pulsation intensity, the effect of geometrical parameters including the plate spacing and the plate free area is investigated as well. moreover, the concept of characteristic velocity models at flooding points is evaluated with respect to the variation of pressure drop along the column at different operational conditions.

关键词： Solvent extraction Pulsed plate column Pressure drop Energy consumption Pulsed flow Characteristic velocity

A fast and accurate dynamic relaxation scheme

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Frontiers of Structural and Civil Engineering 2019年第1期13卷 176-189页

作者： mohammad REZAIEE-PAJAND mohammad mohammadi-KHATAmI Department of Civil Engineering Ferdowsi University of MashhadMashhadIran

Dynamic relaxation method (DRm)is one of the suitable numerical procedures for nonlinear structural *** the fictitious inertia and damping forces to the static equation,and turning it to the dynamic system,are the basis of this *** selection of the DRm artificial factors leads to the better convergence rate and efficient *** study aims to increase the numerical stability,and to decrease the analysis *** fulfil this objective,the reduction rate of analysis error for consecutive iterations is *** on this formulation,a new time step is found for the viscous dynamic *** combining this novel relationship with the other DRm factors,various geometrical nonlinear structures,such as trusses,frames,and shells,are *** obtained results verify the efficiency of authors'scheme.

关键词： viscous dynamic relaxation time step displacement error geometric nonlinear analysis

maximum entropy based finite element analysis of porous media

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 364-379页

作者： Emad NOROUZI Hesam mOSLEmZADEH Soheil mohammadi High Performance Computing Laboratory School of Civil EngineeringFaculty of EngineeringUniversity of TehranTehranIran

The maximum entropy theory has been used in a wide variety of physical, mathematical and engineering applications in the past few years. However, its application in numerical methods, especially in developing new shape functions, has attracted much interest in recent years. These shape functions possess the potential for performing better than the conventional basis functions in problems with randomly generated coarse meshes. In this paper, the maximum entropy theory is adopted to spatially discretize the defonnation variable of the governing coupled equations of porous media. This is in line with the well-known fact that higher-order shape functions can provide more stable solutions in porous problems. Some of the benchmark problems in deformable porous media are solved with the developed approach and the results are compared with available references.

关键词： maximum entropy FEm fully coupled multi-phase system porous media

Reliability assessment of networks-on-chip based on analytical models

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第12期10卷 1801-1814页

作者： mojtaba VALINATAJ Siamak mohammadi Saeed SAFARI School of Electrical and Computer Engineering College of Engineering University of Tehran

As technology scales down, the reliability issues are becoming more crucial, especially for networks-on-chip (NoCs) that provide the communication requirements of multi-processor systems-on-chip. Reliability evaluation based on analytical models is a precise method for dependability analysis before and after designing the fault-tolerant systems. In this paper, we accurately formulate the inherent reliability and vulnerability of some popular NoC architectures against permanent faults, also depending on the employed routing algorithm and traffic model. Based on this analysis, effects of failures in the links, switches and network interfaces on the packet delivery of NoCs are determined. Besides, some extensions to evaluate a fault-tolerant method and some routing algorithms are described. The analyses are validated through appropriate simulations. The results thus obtained are exactly the same as or very close to the analytical ones.

关键词： Networks-on-chip (NoCs) Traffic model Routing algorithm Reliability assessment Permanent fault

Annual growth of Fagus orientalis is limited by spring drought conditions in Iran’s Golestan Province

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Journal of Forestry Research 2024年第1期35卷 128-142页

作者： Khalil Ghorbani Jahangir mohammadi Laleh Rezaei Ghaleh Department of Water Engineering Faculty of Water and Soil EngineeringGorgan University of Agricultural Sciences and Natural ResourcesGorganIran Department of Forestry Gorgan University of Agricultural Sciences and Natural ResourcesGorganIran Department of Water Engineering Faculty of AgricultureUrmia UniversityUrmiaIran

Due to the lack of a uniform and accurate defi-nition of‘drought’,several indicators have been introduced based on different variables and methods,and the efficiency of each of these is determined according to their relationship with *** relationship between two drought indices,SPI(standardized precipitation index)and SPEI(standard-ized precipitation-evapotranspiration index)in different sea-sons was investigated using annual rings of 15 tree samples to determine the effect of drought on the growth of oriental beech(Fagus orientalis Lipsky)in the Hyrcanian forests of northern *** different evapotranspiration calcula-tion methods were evaluated on SPEI efficiency based on Hargreaves-Samani,Thornthwaite,and Penman-monteith methods using the step-by-step m5 decision tree regression *** results show that SPEI based on the Penman-monteith in a three-month time scale(spring)had similar temporal changes and a better relationship with annual tree rings(R^(2)=0.81)at a 0.05 significant *** change and a decreasing trend in the time series of annual tree rings are similar to the variation in the SPEI based on the Penman-monteith *** affecting evapotranspiration,temperature,wind speed,and sunshine hours(used in the Penman-monteith method),increased but precipitation *** non-linear modeling methods,SPEI based on Penman-monteith best illustrated climate changes affecting tree growth.

关键词： Climate change Drought index Hyrcanian forests SPEI'Annual growth rings Fagus orientalis

The Effect of Variable Stator on Performance of a Highly Loaded Tandem Axial Flow Compressor Stage

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Journal of Thermal Science 2016年第3期25卷 223-230页

作者： Hamzeh Eshraghi masoud Boroomand Abolghasem m.Tousi mohammad Toude Fallah Ali mohammadi Department of Aerospace Engineering and Centre of excellence on computational aerospace engineering Amirkabir University of Technology Nanotechnology Research and Application Center Sabanci University

Increasing the aerodynamic load on compressor blades helps to obtain a higher pressure ratio in lower rotational speeds. Considering the high aerodynamic load effects and structural concerns in the design process, it is possible to obtain higher pressure ratios compared to conventional compressors. However, it must be noted that imposing higher aerodynamic loads results in higher loss coemcients and deteriorates the overall performance. To avoid the loss increase, the boundary layer quality must be studied carefully over the blade suction surface. Employment of advanced shaped airfoils （like CDAs）, slotted blades or other boundary layer control methods has helped the de- signers to use higher aerodynamic loads on compressor blades. Tandem cascade is a passive boundary layer control method, which is based on using the flow momentum to control the boundary layer on the suction surface and also to avoid the probable separation caused by higher aerodynamic loads. In fact, the front pressure side flow momentum helps to compensate the positive pressure gradient over the aft blade＇s suction side. Also, in compari- son to the single blade stators, tandem variable stators have more degrees of freedom, and this issue increases the possibility of finding enhanced conditions in the compressor off-design performance. In the current study, a 3D design procedure for an axial flow tandem compressor stage has been applied to design a highly loaded stage. Following, this design is numerically investigated using a CFD code and the stage characteristic map is reported. Also, the effect of various stator stagger angles on the compressor performance and especially on the compressor surge margin has been discussed. To validate the CFD method, another known compressor stage is presented and its performance is numerically investigated and the results are compared with available experimental results.

关键词： Compressor Stage Highly Loaded Performance Characteristic Tandem Variable Stator

The Release Behavior,Biocompatibility and Physical Properties of Aid-loaded Strontium Doped Calcium Phosphate Cement

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Journal of Bionic Engineering 2020年第6期17卷 1209-1223页

作者： maryam mohammadi Sayed mahmood Rabiee Saeed Hesaraki Department of materials Engineering Babol Noshirvani University of TechmologyBabol 71167-47148Iran Nanotechnologv and Advanced materials Materials and Energy Research CenterKaraj ***AlborzIran

The effect of concurrent attendance of two inhibitors of bone degradation,namely Alendronate(Aid)sodium trihydrate and Strontium(Sr),on Calcium Phosphate Cement(CPC)characteristics was *** this aim,5 wt%Strontium and 21 mm Alendronate sodium trihydrate were used in calcium phosphate cement and setting time,ion and drug release were ***264.7 and G cell were cultured on cement samples and Tartrate-Resistant Acid Phosphatase(TRAP),Alkaline phosphatase(ALP)activity and mTT assay were *** results of structural analysis indicated that 21 mm Aid did not let the cement ***,colloidal silica was added to the cement formula and successfully decreased the setting *** vitro tests showed Sr-loaded sample had a greater inhibitory effect on biocompatibility of G cells than Aid-loaded and Sr-Ald-loaded *** addition,the findings about osteoblast mTT and ALP activity indicated that Sr was more effective in osteogenic activity of G *** simultaneous presence of Aid and Sr in Calcium Phosphate Cement(CPC)was not as effective in its biocompatibility as the presence of Sr alone.

关键词： calcium phosphate cements drug release alendronate sodium trihydrate strontium RAW264.7 cell G cell

Two-Dimensional Legendre Wavelets for Solving Time-Fractional Telegraph Equation

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Advances in Applied mathematics and mechanics 2014年第2期6卷 247-260页

作者： m.H.Heydari m.R.Hooshmandasl F.mohammadi Faculty of mathematics Yazd UniversityYazdIran Department of mathematics Faculty of SeiencesHormozgan UniversityBandarabbasIran

In this paper,we develop an accurate and efficient Legendre wavelets method for numerical solution of the well known time-fractional telegraph *** the proposed method we have employed both of the operational matrices of fractional integration and differentiation to get numerical solution of the time-telegraph *** power of this manageable method is *** the use of Legendre wavelet is found to be accurate,simple and fast.

关键词： Telegraph equation Legendre wavelets fractional calculus Caputo derivative.