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Electromagnetic wave absorption performance of Fe_(3)O_(4)/activated carbon-natural resin nanocomposite

新型炭材料（中英文） 2024年第6期39卷 1157-1177页

作者： mahsa mahmoodi Bagher Aslibeiki Reza Peymanfar Hamid Naghshara Rajesh Kumar Rajagopal Yue Zhao Davide Peddis Tapati Sarkar Faculty of Physics University of Tabriz51666-16471TabrizIran Division of Solid State Physics Department of Materials Science and EngineeringUppsala UniversitySE-75103Sweden Department of Chemical Engineering Energy Institute of Higher Education39177-67746SavehIran Iranian Society of Philosophers Department of Science13187-76511TehranIran Peykareh Enterprise Development CO. 15149-45511TehranIran College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China Dipartimento di Chimica e Chimica Industriale&INSTM nbM2-LabUniversitàdegli Studi di GenovaVia Dodecaneso 31I-16146GenoaItaly Institute of Structure of Matter National Research CouncilnM2-LabVia Salaria km 29.300Monterotondo Scalo 00015RomaItaly

There has recently been a fundamental need to develop high efficiency microwave absorbers to reduce electro-magnet-ic *** is often very difficult to obtain superior absorption with only one material,so we have explored composites using fillers of activated carbon derived from biological material(oleaster seeds)and resin(apricot tree gum)with Fe_(3)O_(4) in a paraffin wax matrix to improve the dielectric properties and achieve a high specific surface area.A 1 mm thick layer of a Fe_(3)O_(4)+resin(FEOR),with the magnetic nanoparticles anchored to the gum,resulted in a reflection loss of−71.09 *** compared this with the results for composites using a filler of Fe_(3)O_(4)+activated carbon,and one with a three-component filler of Fe_(3)O_(4)+activated carbon+resin which had a very porous structure that had a direct effect on the surface ***,the FEOR sample had near-ideal im-pedance matching,close to 1,which resulted in high absorption *** addition,the presence of defects improves mi-crowave attenuation by dipole polarization and charge carrier *** work suggests the use of new types of biomaterials to in-crease microwave absorption.

关键词： Activated carbon Oleaster seeds Gum Magnetite Microwave absorption

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Fe3O4/活性炭-天然树脂纳米复合材料的电磁波吸收性能（英文）

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新型炭材料(中英文) 2024年第6期 1157-1177页

作者： mahsa mahmoodi Bagher Aslibeiki Reza Peymanfar Hamid Naghshara Rajesh Kumar Rajagopal Yue Zhao Davide Peddis Tapati Sarkar Faculty of Physics University of Tabriz Division of Solid State Physics Department of Materials Science and EngineeringUppsala University Department of Chemical Engineering Energy Institute of Higher Education Iranian Society of Philosophers Department of Science Peykareh Enterprise Development CO. College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Dipartimento di Chimica e Chimica Industriale&INSTM nbM2-LabUniversitàdegli Studi di GenovaVia Dodecaneso 31 Institute of Structure of Matter National Research CouncilnM2-LabVia Salaria km 29300Monterotondo Scalo 00015

近期，迫切需要开发高效的微波吸收材料以降低电磁污染。单一材料通常难以实现优异的吸附性能，本研究探索了由生物材料（沙枣籽）和树脂（杏树胶）衍生的活性炭与Fe3O4的复合材料，以提高复合材料的介电性能并实现高比表面积。1 mm厚的... 详细信息

近期，迫切需要开发高效的微波吸收材料以降低电磁污染。单一材料通常难以实现优异的吸附性能，本研究探索了由生物材料（沙枣籽）和树脂（杏树胶）衍生的活性炭与Fe3O4的复合材料，以提高复合材料的介电性能并实现高比表面积。1 mm厚的Fe3O4/树脂（FEOR）纳米复合材料中，磁性纳米粒Fe3O4子锚定在杏树胶上，注入石蜡后，实现了-71.09 dB的反射损失。将其与由Fe3O4/沙枣籽衍生活性炭组成的纳米复合材料以及具有多孔结构的三组分Fe3O4/活性炭/树脂样品的结果进行对比，发现FEOR的多孔结构对表面极化有直接影响。然而，FEOR样品具有接近理想的阻抗匹配（接近1），这导致了高电磁波吸收性能。此外，材料中的缺陷在通过偶极子极化和电荷载流子捕获而改善了微波衰减。

关键词：活性炭沙枣籽杏树胶磁铁电磁波吸收

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Optimal motion cueing algorithm for accelerating phase of manned spacecraft in human centrifuge

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Chinese Journal of Aeronautics 2020年第7期33卷 1991-2001页

作者： Ali mahmoodi Isooda KAZEMI Department of Aerospace Engineering Science and Research BranchIslamic Azad UniversityTehran ***Iran

This paper presents a novel optimal Motion Cueing Algorithm(MCA)to control the rotations of a Human Centrifuge(HC)and achieve the best simulation of a Space Craft(SC)*** of the specific forces sensed by astronauts of the SC and the HC have been derived and linearized.A Linear Quadratic Regulator(LQR)controller is implemented for the problem which tends to minimize the error between the two sensed specific forces as well as control input in a cost *** results in control inputs of the HC to generate its sensed specific force as close as possible to the one in the *** algorithm is implemented for both linearized and nonlinear portions of a US space shuttle mission trajectory as a verification using *** longitudinal direction,the proposed MCA,works well when the acceleration is less than 2 g in which the tracking error does not exceed 12%.In lateral direction the tracking is much better even in nonlinear region since the error remains less than 7%for tilting up to 50°.Finally,the effect of weight matrixes in the LQR cost function on overall weight and power of the HC motion system is discussed.

关键词： Accelerating phase Human centrifuge Manned spacecraft Optimal motion cueing Specific force

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Kerosene-alumina nanofluid flow and heat transfer for cooling application

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Journal of Central South University 2016年第4期23卷 983-990页

作者： M.mahmoodi Sh.Kandelousi Department of Aerospace Engineering Malek-Ashtar University of Technology Department of Mechanical Engineering Babol University of Technology

Kerosene-alumina nanofluid flow and heat transfer in the presence of magnetic field are studied. The basic partial differential equations are reduced to ordinary differential equations which are solved semi analytically using differential transformation method. Velocity and temperature profiles as well as the skin friction coefficient and the Nusselt number are determined analytically. The influence of pertinent parameters such as magnetic parameter, nanofluid volume fraction, viscosity parameter and Eckert number on the flow and heat transfer characteristics is discussed. Results indicate that skin friction coefficient decreases with increase of magnetic parameter, nanofluid volume fraction and viscosity parameter. Nusselt number increases with increase of magnetic parameter and nanofluid volume fraction while it decreases with increase of Eckert number and viscosity parameter.

关键词： magnetic field nanofluid heat transfer differential transformation method

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HEAT-RESISTANT PYRIDINE-BASED POLY(ETHER-ESTER)S: SYNTHESIS, CHARACTERIZATION AND PROPERTIES

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Chinese Journal of Polymer Science 2013年第1期31卷 171-178页

作者： Shahram Mehdipour-Ataei Ali mahmoodi Department of Chemistry Islamic Azad University

A pyridine-based diacid was synthesized via nucleophilic substitution reaction of 4-hydroxy benzoic acid with 2,6- dichloropyridine in the presence of potassium carbonate. The diacid was characterized using FT-IR and 1H-NMR spectroscopic methods and also with elemental analysis. Polycondensation reaction of the diacid with different diols including 1,4-dihydroxy benzene, 1,5-dihydroxy naphthalene, bis-phenol A and bis-phenol-P resulted in preparation of pyridine-based poly（ether-ester）s. The polymers were characterized and their physical and thermal properties including inherent viscosity, molecular weight, solubility, thermal stability, thermal behavior and crystallinity were studied. They revealed high heat-resistance and improved solubility in polar solvents. Structure-property relations for the prepared polyester were also studied.

关键词： Polyester Polymer synthesis and characterization Thermal properties Structure-property relations.

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An optimal energy management development for various configuration of plug-in and hybrid electric vehicle

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Journal of Central South University 2015年第5期22卷 1737-1747页

作者： Morteza Montazeri-Gh Mehdi mahmoodi-K Systems Simulation and Control Laboratory School of Mechanical EngineeringIran University of Science and Technology Tehran P.O.Box 16846-13114 Iran

Due to soaring fuel prices and environmental concerns, hybrid electric vehicle(HEV) technology attracts more attentions in last decade. Energy management system, configuration of HEV and traffic conditions are the main factors which affect HEV's fuel consumption, emission and performance. Therefore, optimal management of the energy components is a key element for the success of a HEV. An optimal energy management system is developed for HEV based on genetic algorithm. Then, different powertrain system component combinations effects are investigated in various driving cycles. HEV simulation results are compared for default rule-based, fuzzy and GA-fuzzy controllers by using ADVISOR. The results indicate the effectiveness of proposed optimal controller over real world driving cycles. Also, an optimal powertrain configuration to improve fuel consumption and emission efficiency is proposed for each driving condition. Finally, the effects of batteries in initial state of charge and hybridization factor are investigated on HEV performance to evaluate fuel consumption and emissions. Fuel consumption average reduction of about 14% is obtained for optimal configuration data in contrast to default configuration. Also results indicate that proposed controller has reduced emission of about 10% in various traffic conditions.

关键词： plug-in and hybrid electric vehicle energy management configuration genetic fuzzy controller fuel consumption emission

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Nonlinear integral resonant controller for vibration reduction in nonlinear systems

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Acta Mechanica Sinica 2016年第5期32卷 925-934页

作者： Ehsan Omidi S.Nima mahmoodi Nonlinear Intelligent Structures Laboratory Department of Mechanical Engineering The University of Alabama

A new nonlinear integral resonant controller（NIRC） is introduced in this paper to suppress vibration in nonlinear oscillatory smart structures. The NIRC consists of a first-order resonant integrator that provides additional damping in a closed-loop system response to reduce highamplitude nonlinear vibration around the fundamental resonance frequency. The method of multiple scales is used to obtain an approximate solution for the closed-loop *** closed-loop system stability is investigated using the resulting modulation equation. Finally, the effects of different control system parameters are illustrated and an approximate solution response is verified via numerical simulation *** advantages and disadvantages of the proposed controller are presented and extensively discussed in the results. The controlled system via the NIRC shows no high-amplitude peaks in the neighboring frequencies of the resonant mode,unlike conventional second-order compensation *** makes the NIRC controlled system robust to excitation frequency variations.

关键词： Active vibration control Cantilever Highamplitude oscillation Method of multiple scales Nonlinear vibration Piezoelectric actuator Smart structure

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Design of an optimal active stabilizer mechanism for enhancing vehicle rolling resistance

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Journal of Central South University 2016年第5期23卷 1142-1151页

作者： Yaghoub Pourasad Mehdi mahmoodi-k Majid Oveisi Faculty of Electrical Engineering Urmia university of Technology Young Researches and Elite Club Tabriz BranchIslamic Azad University Department of Marine Engineering Chabahar Maritime University

Improving rollover and stability of the vehicles is the indispensable part of automotive research to prevent vehicle rollover and *** main objective of this work is to develop active control mechanism based on fuzzy logic controller(FLC) and linear quadratic regulator(LQR) for improving vehicle path following,roll and handling performances simultaneously.3-DOF vehicle model including yaw rate,lateral velocity(lateral dynamic) and roll angle(roll dynamic) were *** controller produces optimal moment to increase stability and roll margin of vehicle by receiving the steering angle as an input and vehicle variables as a feedback *** effectiveness of proposed controller and vehicle model were evaluated during fishhook and single lane-change *** results demonstrate that in both cases(FLC and LQR controllers) by reducing roll angle,lateral acceleration and side slip angles remain under 0.6g and 4° during maneuver,which ensures vehicle stability and handling ***,the sensitivity and robustness analysis of developed controller for varying longitudinal speeds were investigated.

关键词： vehicle dynamics rollover handling FLC LQR

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Experimental investigation of flow and distortion mitigation by mechanical vortex generators in a coupled serpentine inlet-turbofan engine system

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Chinese Journal of Aeronautics 2020年第5期33卷 1375-1391页

作者： Iman MAGHSOUDI Mohammad Ali VAZIRY Mostafa mahmoodi Department of Aerospace Malek-Ashtar University of TechnologyTehran 158751774Iran Department of Aerospace Malek-Ashtar University of TechnologyIsfahanShahinshahr 115/83145Iran

The performance of compact,aggressive ducts in advanced propulsion systems is limited by the internal flow separation coupled with the formation of secondary counter-rotating vortices that give rise to intensive flow distortions at the duct *** experimental investigation was conducted to study the flow field and passive suppression of flow separation and Aerodynamic Interface Plane (AIP) distortion in a serpentine air inlet *** were performed by a turbofan engine at several Engine Operating Points (EOPs) from 56%(idle) to 100%(max).A large total pressure deficit region arose at the upper part of the AIP,which was associated with the upper surface flow *** the new mechanical S-type vortex generators in two longitudinal positions (VGl and VG2),separation and loss were diminished at the upper part of the duct and *** VG2 arrangement attained the maximum reductions in distortion coefficients which were 73.72%,60.7% and 37.8% in DC(90°),DC(60°) and△P_C/P metrics,*** the next step of the study,some unsteady aspects of the flow field were analyzed inside the *** separation onset and reattachment points were determined by the standard deviation of static pressure on the upper *** AIP spectral distribution showed that the boundary of low pressure and high pressure recovery regions was dominated by the maximum ***,the PSD diagram of several probes at AIP revealed the vortex shedding frequency and its higher harmonics at separation *** energy content of distinct unsteady spectral features in the bare configuration was significantly reduced using VGs,which showed the improvement of flow at the duct exit.

关键词： Distortion coefficient Power spectral density Serpentine inlet Total pressure Vortex generators

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Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 407-424页

作者： M.SAFI M.VAKILIFARD M.J.mahmoodi Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of Mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COMSOL *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

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