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Hydrodynamic and heat transfer properties of magnetic fluid in porous medium considering nanoparticle shapes and magnetic field-dependent viscosity

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Chinese Journal of Chemical Engineering 2020年第2期28卷 329-339页

作者： mohsen izadi Masoud Javanahram Seyed mohsen Hashem Zadeh Dengwei Jing Mechanical Engineering Department Lorestan UniversityKhorramabadIran Mechanical Engineering Department Islamic Azad UniversityBushehrIran Department of Mechanical Engineering Shahid Chamran University of AhvazIran School of Energy and Power Engineering State Key Lab of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

The purpose of this paper is to study the characteristics of the combined convection heat transfer and a micropolar nanofluid flow passing through an impermeable stretching sheet in a porous *** nanofluid flow field is affected by a magnetic field perpendicular to the *** dynamic viscosity of the micropolar nanofluid changes under the influence of the magnetic *** continuity,linear momentum,angular momentum,and energy equations are first simplified using the order of magnitude technique that,along with the applied boundary conditions and the definition of the appropriate parameters,are transferred to the similarity space using the similarity *** the resulting equations are solved using the Runge–Kutta *** distinction of the macroscale and microscale flow fields and temperature fields resulting from different nanoparticle shapes was *** the Hartmann number,the vortex viscosity parameter,the magnetic parameter,the nanoparticle volume fraction,and the permeability parameter of the porous media increased the surface friction on the *** the vortex viscosity parameter,the magnetic parameter,and the volume fraction of the nanoparticles increases the Nusselt number.

关键词： MHD-combined convection Porous media Magnetic micropolar nanofluid

Natural Convection Heat Transfer in a Porous Cavity with Sinusoidal Temperature Distribution Using Cu/Water Nanofluid: Double MRT Lattice Boltzmann Method

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Communications in Computational Physics 2021年第1期29卷 292-318页

作者： Hasan Sajjadi Amin Amiri Delouei Rasul Mohebbi mohsen izadi Sauro Succi Department of Mechanical Engineering Faculty of EngineeringUniversity of BojnordBojnordIran School of Engineering Damghan UniversityDamghanIran Mechanical Engineering Department Faculty of EngineeringLorestan UniversityKhorramabadIran Center for Life Nanoscience Italian Institute of TechnologyViale Regina Margherita 29500161RomaItaly Physics Department Harvard University29 Oxford StreetCambridgeMA 02138USA

In this study,natural convection flow in a porous cavity with sinusoidal temperature distribution has been analyzed by a new double multi relaxation time(MRT)Lattice Boltzmann method(LBM).We consider a copper/water nanofluid filling a porous *** simulating the temperature and flow fields,D2Q5 and D2Q9 lattices are utilized respectively,and the effects of different Darcy numbers(Da)(0.001-0.1)and various Rayleigh numbers(Ra)(10^(3)-10^(5))for porosity(ε)between 0.4 and 0.9 have been *** deviation(θ)changed from 0 toπand the volume fraction of nanoparticles(∅)varied from 0 to 6%.The present results show a good agreement with the previous works,thus confirming the reliability the new numerical method proposed in this *** is indicated that the heat transfer rate increases at increasing Darcy number,porosity,Rayleigh number,the volume fraction of nanoparticles and phase ***,the most sensitive parameter is the Rayleigh *** maximum Nusselt deviation is 10%,32%and 33%for Ra=10^(3),10^(4) and 10^(5),respectively,withε=0.4 toε=*** can be concluded that the effect of Darcy number on the heat transfer rate increases at increasing Rayleigh number,yielding a maximum enhancement of the average Nusselt number around 12%and 61%for Ra=10^(3) and Ra=10^(5),respectively.

关键词： Porous media double multi relaxation time-lattice Boltzmann method nanofluid natural convection sinusoidal temperature distribution

Enhancement of simultaneous nitrogen and phosphorus removal using intermittent aeration mechanism

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Journal of Environmental Sciences 2021年第11期33卷 1-14页

作者： Parnian izadi Parin izadi Ahmed Eldyasti Civil engineering York university4700 Keele StTorontoONCanada

Biological nutrient removal grows into complicated scenario due to the microbial consortium shift and kinetic competition between phosphorus(P)-accumulating and nitrogen(N)-removing *** this study,three sequential batch reactors with constant operational conditions except aeration patterns at 6 h cycle periods were *** aeration was applied to develop a robust nutrient removal system aimed to achieve high energy saving and removal *** results showed higher correspondence of Puptake,polymeric substance synthesis and glycogen degradation in intermittent-aeration with longer interval periods compared to *** the intermittentaeration duration from 25 to 50 min,resulted in higher process performance where the system exhibited approximately 30%higher nutrient *** study indicated that nutrient removal strongly depends on reaction phase configuration representing the importance of aeration *** microbial community examined the variation in abundance of bacterial groups in suspended sludge,where the 50 min intermittent aeration,favored the growth of P-accumulating organisms and nitrogen removalmicrobial groups,indicating the complications related to nutrient removal *** intermittently aerated process with high capability of simple implementation to conventional systems by elemental retrofitting,is applicable for upgrading wastewater treatment *** aeration as a major operational cost,this process is a promising approach to potentially remove nutrients in high competence,in distinction to optimizing cost-efficacy of the system.

关键词： EBPR Nutrient removal Intermittent aeration Dissolved oxygen PAO Polyhydroxyalkanoate

Finite element model updating for structural damage detection using transmissibility data

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 87-101页

作者： Ahmad izadi Akbar Esfandiari Department of Maritime Engineering Amirkabir University of TechnologyTehran 15875-4413Iran

This paper presents a new finite element model updating method for estimating structural parameters and detecting structural damage location and severity based on the structural responses(output-only data).The method uses the sensitivity relation of transmissibility data through a least-squares algorithm and appropriate normalization of the extracted *** proposed transmissibility-based sensitivity equation produces a more significant number of equations than the sensitivity equations based on the frequency response function(FRF),which can estimate the structural parameters with higher *** abilities of the proposed method are assessed by using numerical data of a two-story two-bay frame model and a plate structure *** evaluating different damage cases,the number,location,and stiffness reduction of the damaged elements and the severity of the simulated damage have been accurately *** reliability and stability of the presented method against measurement and modeling errors are examined using error-contaminated *** parameter estimation results prove the method’s capabilities as an accurate model updating algorithm.

关键词： damage detection model updating output-only transmissibility sensitivity equation

Improvement of mechanical behavior of buried pipelines subjected to strike-slip faulting using textured pipeline

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Frontiers of Structural and Civil Engineering 2019年第5期13卷 1105-1119页

作者： Mahdi izadi Khosrow BARGI School of Civil Engineering College of EngineeringUniversity of TehranTehranIran

The present study investigates the mechanical behavior of a new generation of buried pipelines, dubbed the textured pipeline, which is subjected to strike-slip faulting. In conventional cylindrical pipelines, the axial and bending stresses brought about in their walls as a result of fault movement, lead to local buckling, which is construed as one of the major reasons contributing to pipeline failure. The present study has assessed 3-D numerical models of two kinds of buried textured pipelines, with 6 and 12 peripheral triangular facets, subjected to a strike-slip faulting normal to the axis of the pipelines, with and without internal pressure, with the two kinds of X65 and X80 steel, and with different diameter-to-thickness ratios. The results indicate that, because of specific geometry of this pipeline shell which is characterized by having lower axial stiffness and higher bending stiffness, compared to conventional cylindrical pipeline, they are considerably resistant to local (buckling. The results of this study can be conceived of as a first step toward comprehensive seismic studies on this generation of pipelines which aim at replacing the conventional cylindrical pipelines with textured ones in areas subjected to fault movement.

关键词： buried pipeline textured pipeline local buckling

Combined load bearing capacity of rigid piles embedded in a crossanisotropic clay deposit using 3D finite element lower bound

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第3期15卷 717-737页

作者： Ardavan izadi Reza Jamshidi Chenari Department of Civil Engineering Faculty of EngineeringUniversity of GuilanRashtGuilanIran

In this study,an iterative-based three-dimensional finite element lower bound in association with the second-order cone programming method is adopted to evaluate the limit load of a single pile embedded in cross-anisotropic soils under general loading *** lower bound solutions of the pile embedded in an anisotropic soil deposit can be found by formulating the element equilibrium,equilibrium of shear and normal stresses along discontinuities,boundary conditions,yield function,and optimizing the objective function through the second-order cone programming method in conjunction with an iterative-based update procedure.A general loading condition is considered to profile the expansion of the safe load in the vertical-horizontal-moment(V-H-M)*** results of this study are compared and validated against three different cases including an isotropic lateral loading,anisotropic end bearing capacity,and a pile embedded in an isotropic soil deposit under general loading condition.A parametric study is conducted to evaluate the impact of different influencing *** was found that the effect of anisotropy on the variation of lateral limit load of a single pile is more pronounced than the corresponding vertical and bending moment limit loads,whereas the interface properties have more significant effects on the vertical and bending moment limit loads in comparison to the lateral limit load.

关键词： Rigid pile Cross-anisotropy Clay Combined loading Three-dimensional finite element lower bound

Applying Sliding Mode Control to Suppress Double Frequency Voltage Ripples in Single-phase Quasi-Z-source Inverters

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CSEE Journal of Power and Energy Systems 2023年第2期9卷 671-681页

作者： Jaber Merrikhi Ahangarkolaei Mahdi izadi Tohid Nouri Department of Electrical Engineering Sari BranchIslamic Azad UniversitySariIran Department of Electrical Engineering Shahriar BranchIslamic Azad UniversityShahriarIran

The inherent double-line frequency ripple(DFR)of the single-phase quasi-Z-Source inverter(qZSI)strongly affects performance and design of the whole system,which requires hardware improvement methods such as additional semiconductor components or increasing the volume of capacitors and *** a result,hardware solutions increase the price,and the volume and also reduces reliability of the *** this paper,as a non-hardware solution,a sliding mode control(SMC)method is presented to control the voltage of the qZSI *** suppress the DFR,a second-order harmonic is injected into the capacitor reference *** and experimental results show that the introduced controller will have satisfactory results in reducing the DFR without any hardware changes in the qZSI,such as increasing the volume of the capacitor and inductor,adding a semiconductor,or increasing the frequency.A simulation model and experimental prototype are provided to demonstrate the validation of the effectiveness of the proposed controller.

关键词： Double-frequency ripple quasi-Z-source inverter sliding mode control

Edge-Dependent Electronic and Magnetic Characteristics of Freestanding β_(12)-Borophene Nanoribbons

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Nano-Micro Letters 2018年第1期10卷 124-136页

作者： Sahar izadi Vishkayi Meysam Bagheri Tagani Department of Physics Computational Nanophysics Laboratory (CNL) University of Guilan

This work presents an investigation of nanoribbons cut from β_(12)-borophene sheets by applying the density functional theory. In particular, the electronic and magnetic properties of borophene nanoribbons(BNR) are studied. It is found that all the ribbons considered in this work behave as metals, which is in good agreement with the recent experimental results. β_(12)-BNR has significant diversity due to the existence of five boron atoms in a unit cell of the sheet. The magnetic properties of the ribbons are strongly dependent on the cutting direction and edge profile. It is interesting that a ribbon with a specific width can behave as a normal or a ferromagnetic metal with magnetization at just one edge or two edges. Spin anisotropy is observed in some ribbons, and the magnetic moment is not found to be the same in both edges in an antiferromagnetic configuration. This effect stems from the edge asymmetry of the ribbons and results in the breaking of spin degeneracy in the band structure. Our findings show that β_(12) BNRs are potential candidates for next-generation spintronic devices.

关键词： Borophene nanoribbons Electronic and magnetic properties Density functional theory

Analyzing uncertainties involved in estimating collapse risk with and without considering uncertainty probability distribution parameters

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Earthquake Engineering and Engineering Vibration 2022年第1期21卷 101-116页

作者： Mohammad Amin Bayari Naser Shabakhty Esmaeel izadi Zaman Abadi Department of Civil Engineering Najafabad BranchIslamic Azad UniversityNajafabad ***Iran School of Civil Engineering Iran University of Science and TechnologyTehran 16844Iran

In the present study,modified Ibarra,Medina and Krawinkler moment-rotation parameters are used for modeling the uncertainties in concrete moment frame *** of model parameters in a component and between two structural components were considered to analyze these *** the first step,the structural collapse responses were obtained by producing 281 samples for the uncertainties using the Latin hypercube sampling(LHS)method,considering the probability distribution of the uncertainties and performing incremental dynamic *** the second step,281 new samples were produced for the uncertainties by the central composite design(CCD)method without considering the probability distribution of the uncertainties and calculating the structural collapse ***,using the response surface method(RSM)and artificial neural network(ANN)for the two simulation modes,structural collapse responses were *** results indicated that the collapse responses at levels of 0 to 100%obtained from the two simulations have a high correlation coefficient of 98%.This suggests that random variables can be simulated without considering the probability distribution of uncertainties,by performing uncertainty analysis to determine structural collapse responses.

关键词： uncertainty analysis collapse response artificial neural network response surface method