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Effect of Bainite Morphology on Mechanical Properties of the Mixed Bainite-martensite Microstructure in D6AC Steel

Journal of Materials Science & Technology 2012年第4期28卷 336-342页

作者： Khodamorad abbaszadeh Hassan Saghafian Shahram Kheirandish School of Metallurgy and Materials Engineering Iran University of Science and Technology Tehran *** Iran

The effect of bainite morphology on mechanical properties of the mixed bainite-martensite microstructure in D6AC low alloy ultra-high strength steel has been studied in the present work. For this purpose, samples austenitized at 910℃ for 40 min were quenched in three different ways. Some of the samples were directly oil-quenched, some others were quenched in salt bath at 330 ℃ and the remaining samples were quenched in salt bath at 425 ℃ for various holding times. All samples were tempered at 200 ℃ for 2 h. Microstructures were examined by optical microscopy （OM） and scanning electron microscopy （SEM）. Fracture surfaces also were studied by SEM. Results showed that the mixed microstructure containing martensite and 28 vol.% of the lower bainite exhibited higher yield and tensile strengths than the fully martensitic microstructure. This could be mainly attributed to the partitioning of the prior austenite grains by the lower bainite and enhancing the strength of lower bainite in the mixed microstructure by plastic constraint. Charpy V-notch （CVN） impact energy and ductility were improved by increasing the volume fraction of the lower bainite. This is not the case about the mixed microstructure containing the upper bainite and martensite. As a result, the tensile and CVN impact properties of mixed upper bainite-martensite microstructure are lower than those of the fully martensitic microstructure. Finally, fractography studies showed cleavage fracture at the surface of CVN impact specimens with martensitic and upper bainitic microstructures confirming the tendency to brittle behavior.

关键词： Upper bainite Lower bainite Microstructure D6AC Mechanical properties

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A Design Concept and Kinematic Model for a Soft Aquatic Robot with Complex Bio-mimicking Motion

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Journal of Bionic Engineering 2022年第1期19卷 16-28页

作者： shok.ofeh abbaszadeh Roberto Leidhold Stefan Hoerner Institute of Electrical Power Systems Department of Electrical Engineering and Information TechnologyOtto-Von-Guericke University of MagdeburgUniversitätsplatz 239106MagdeburgGermany Institute of Fluid Dynamics and Thermodynamics Department of Process and Systems EngineeringOtto-Von-Guericke University of MagdeburgUniversitätsplatz 239106MagdeburgGermany

Fish mortality assessments for turbine passages are currently performed by live-animal testing with up to a hundred thousand fish per year in Germany.A propelled sensor device could act as a fish *** this context,the study presented here investigates the state of the art via a thorough literature review on propulsion systems for aquatic *** evaluation of propulsion performance,weight,size and complexity of the motion achievable allows for the selection of an optimal concept for such a fish mimicking device carrying the *** the second step,the design of a bioinspired soft robotic fish driven by an unconventional drive system is *** is based on piezoceramic actuators,which allow for motion with five degrees of freedom(DOF)and the creation of complex bio-mimicking body motions.A kinematic model for the motion’s characteristics is developed,to achieve accurate position feedback with the use of strain *** measurements validate the complex deformation of the body and deliver the basis for the calibration of the kinematic ***,it can be shown,that the calibrated model presented allows the tracking of the deformation of the entire body with an accuracy of 0.1 mm.

关键词： Unconventional drive system Biologically inspired robots Biomimetics Flexible robots

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Second-Order Finite Difference/Spectral Element Formulation for Solving the Fractional Advection-Diffusion Equation

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Communications on Applied Mathematics and Computation 2020年第4期2卷 653-669页

作者： Mostafa abbaszadeh Hanieh Amjadian Department of Applied Mathematics Faculty of Mathematics and Computer SciencesAmirkabir University of TechnologyNo.424Hafez Ave.Tehran 15914Iran

The main aim of this paper is to analyze the numerical method based upon the spectral element technique for the numerical solution of the fractional advection-diffusion *** time variable has been discretized by a second-order finite difference *** stability and the convergence of the semi-discrete formula have been ***,the spatial variable of the main PDEs is approximated by the spectral element *** convergence order of the fully discrete scheme is *** basis functions of the spectral element method are based upon a class of Legendre *** numerical experiments confirm the theoretical results.

关键词： Spectral method Finite diference method Fractional advection-difusion equation Galerkin weak form Unconditional stability

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CFD-DEM modelling of mixing and segregation of binary mixtures of ellipsoidal particles in liquid fluidizations

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Journal of Hydrodynamics 2019年第6期31卷 1190-1203页

作者： Esmaeil abbaszadeh Molaei Aibing Yu Zongyan Zhou Laboratory for Simulation and Modelling of Particulate Systems Department of Chemical EngineeringMonash UniversityClaytonVic 3800Australia

Solid-liquid fluidized beds of binary mixtures are widely used in many *** segregation may occur as particles can differ in size,density,or *** studies have been conducted in the past to understand the effects of particlesize and density on the mixing and segregation,but the effect of particle shape has not been well ***,in the present work,CFD-DEM approach is employed to perform a numerical analysis of the effect of particle shape on the particle mixing and segregation phenomenon in liquid fluidization *** particle shapes from oblate to prolate are produced by varying aspect ratio of ellipsoids from 0.25 to 3,and eight binary mixtures of spheres and ellipsoids are *** results show that when oblate or prolate particles are added to spheres,the segregation takes *** segregation degree increases with particle aspect ratio diverging from 1.0 and also liquid superficial *** relationship of mixing index with aspect ratio under different liquid velocities is established,and a detailed explanation is *** is revealed that increasing the projected area and hence the drag force results in the separation of ellipsoidal particles from spheres.

关键词： Mixing segregation binary mixture ellipsoids liquid fluidization CFD-DEM

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An ensemble method for data stream classification in the presence of concept drift

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Frontiers of Information Technology & Electronic Engineering 2015年第12期16卷 1059-1068页

作者： Omid abbaszadeh Ali AMIRI Ali Reza KHANTEYMOORI Department of Computer Engineering University of Zanjan

One recent area of interest in computer science is data stream management and processing. By ‘data stream', we refer to continuous and rapidly generated packages of data. Specific features of data streams are immense volume, high production rate, limited data processing time, and data concept drift; these features differentiate the data stream from standard types of data. An issue for the data stream is classification of input data. A novel ensemble classifier is proposed in this paper. The classifier uses base classifiers of two weighting functions under different data input conditions. In addition, a new method is used to determine drift, which emphasizes the precision of the algorithm. Another characteristic of the proposed method is removal of different numbers of the base classifiers based on their quality. Implementation of a weighting mechanism to the base classifiers at the decision-making stage is another advantage of the algorithm. This facilitates adaptability when drifts take place, which leads to classifiers with higher efficiency. Furthermore, the proposed method is tested on a set of standard data and the results confirm higher accuracy compared to available ensemble classifiers and single classifiers. In addition, in some cases the proposed classifier is faster and needs less storage space.

关键词： Data stream Classificaion Ensemble classifiers Concept drift

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A Nonlinear Optimal Control Approach for Bacterial Infections Under Antibiotics Resistance

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Journal of Systems Science & Complexity 2024年第6期37卷 2293-2317页

作者： RIGATOS Gerasimos abbaszadeh Masoud SIANO Pierluigi AL-NUMAY Mohammed ZOUARI Farouk Unit of Industrial Automation Industrial Systems Institute26504Rion PatrasGreece Dept.of ECS Engineering Rensselaer Polytechnic Institute12065TroyNYUSA Dept.of Management and Innovation Systems University of Salerno84084FiscianoItaly Dept.of Electrical Eng. King Saud UniversityRiyadh 11421Saudi Arabia Laboratoire d'Automatique ENIT Tunisie1002 Tunis

The overuse and misuse of antibiotics has become a major problem for public *** become resistant to antibiotics and because of this the anticipated therapeutic effect is never ***-hospital infections are often aggravated and large amounts of money are spent for treating complications in the patients'*** this paper a nonlinear optimal(H-infinity)control method is developed for the dynamic model of bacterial infections exhibiting resistance to ***,differential flatness properties are proven for the associated state-space ***,the state-space description undergoes approximate linearization with the use of first-order Taylor series expansion and through the computation of the associated Jacobian *** linearization process takes place at each sampling instance around a time-varying operating point which is defined by the present value of the system's state vector and by the last sampled value of the control inputs *** the approximately linearized model of the system a stabilizing H-infinity feedback controller is *** compute the controller's gains an algebraic Riccati equation has to be repetitively solved at each time-step of the control *** global stability properties of the control scheme are proven through Lyapunov *** proposed method achieves stabilization and remedy for the bacterial infection under moderate use of antibiotics.

关键词： Bacterial infection differential flatness properties global stability Jacobian matrices nonlinear H-infinity control resistance to antibiotics Riccati equation Taylor series expansion

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Accurate 3D Thermal Network Development for Direct-drive Outer-rotor Hybrid-PM Flux-switching Generator

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Chinese Journal of Electrical Engineering 2024年第2期10卷 80-92页

作者： Ali Zarghani Mohammad Farahzadi Aghil Ghaheri Karim abbaszadeh Faculty of Electrical Engineering Shahid Beheshti UniversityTehran ***Iran Faculty of Electrical Engineering University of Science and CultureTehran ***Iran Department of Electrical Engineering K.N.Toosi University of TechnologyTehran ***Iran

Heat and thermal problems are major obstacles to achieving high power density in compact permanent magnet(PM)***,a comprehensive,accurate,and rapid temperature rise estimation method is required for novel electric machines to ensure safe and reliable operations.A unique three-dimensional(3D)lumped parameter thermal network(LPTN)is presented for accurate thermal modeling of a newly developed outer-rotor hybrid-PM flux switching generator(OR-HPMFSG)for direct-drive ***,the losses of the OR-HPMFSG are calculated using 3D finite element analysis(FEA).Subsequently,all machine components considering the thermal contact resistance,anisotropic thermal conductivity of materials,and various heat flow paths are comprehensively modeled based on the thermal *** the proposed 3-D LPTN,internal nodes are considered to predict the average temperature as well as the hot spots of all active and passive *** measurements are performed on a prototype OR-HPMFSG to validate the efficiency of the 3-D LPTN.A comparison of the results at various operating points between the developed 3-D LPTN,experimental test,and FEA indicates that the 3-D LPTN quickly approximates the hotspot and mean temperature of all components under both transient and steady states with high accuracy.

关键词： Direct-drive wind turbine hybrid-PM flux switching generator lumped parameter thermal network temperature estimation 3D thermal modeling

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Nonlinear robust H-infinity filtering for a class of uncertain systems via convex optimization

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控制理论与应用（英文版） 2012年第2期10卷 152-158页

作者： Masoud abbaszadeh Horacio J. MARQUEZ United Technologies Research Center East HartfordCT 06108U.S.A. Department of Electrical and Computer Engineering University of AlbertaEdmontonAlbertaCanada T6G 2V4

A new approach for robust H-infinity filtering for a class of Lipschitz nonlinear systems with time-varying uncertainties both in the linear and nonlinear parts of the system is proposed in an LMI framework. The admissible Lipschitz constant of the system and the disturbance attenuation level are maximized simultaneously through convex multi-objective optimization. The resulting H-infinity filter guarantees asymptotic stability of the estimation error dynamics with exponential convergence and is robust against nonlinear additive uncertainty and time-varying parametric uncertainties. Explicit bounds on the nonlinear uncertainty are derived based on norm-wise and element-wise robustness analysis.

关键词： Nonlinear uncertain systems Robust observers Nonlinear H-infinity filtering Convex optimization

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Microplastics in the atmosphere of Ahvaz City, Iran

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Journal of Environmental Sciences 2023年第4期126卷 95-102页

作者： Sajjad Abbasi Neamatollah Jaafarzadeh Amir Zahedi Maryam Ravanbakhsh Somayeh abbaszadeh Andrew Turner Department of Earth Sciences College of ScienceShiraz UniversityShiraz 71454Iran Department of Radiochemistry and Environmental Chemistry Faculty of ChemistryMaria Curie-Skłodowska UniversityLublin 20-031Poland Environmental Technologies Research Center Ahvaz Jundishapur University of Medical SciencesAhvazIran Department of Environmental Health Engineering Shoushtar Faculty of Medical SciencesShoushtarIran Student Research Committee Ahvaz Jundishapur University of Medical SciencesAhvazIran School of Geography Earth and Environmental SciencesPlymouth UniversityPL48AAUK

Airborne particulate matter(PM) with an aerodynamic size cutoff of 10 μm(PM_(10)) has been collected using a high volume air sampler at two locations(urban and residential) in the city of Ahvaz, Iran, for sixteen 24-hour periods over four months(late summer to early winter).Microplastics(MPs) in the PM were isolated after sample digestion and were subsequently characterised by established techniques. All MPs sampled(n = 322) were of a fibrous nature,with polyethylene terephthalate, nylon and polypropylene being the dominant polymers and consistent with textiles and fabrics as the principal source. Despite a distinct seasonality(temperature and wind) over the study period, the abundance, size and colour of the fibres exhibited no clear temporal trend, and no clear differences were observed between the two sites. Concentrations of MPs ranged from none detected to about 0.017/m^(3)(median = 0.0065/m^(3)) and are at the low end of ranges reported in the recent literature for various urban and remote locations. While some MPs may have a local origin, the weathering of other MPs and their acquisition of extraneous geosolids and salts suggests that long-range transport is also important. Back-trajectory calculations indicate that regional sources are mainly to the north and west of Ahvaz, but a southerly, maritime source is also possible in late autumn. Although concentrations of MPs in the atmosphere are well below those encountered in indoor air, further studies are required to elucidate their potential ecological impacts.

关键词： Microplastics Atmosphere Transport Fibres Polymers Ahvaz

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Experimental evaluation of blanking and piercing of PVC based composite and hybrid laminates

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Advances in Manufacturing 2016年第3期4卷 248-256页

作者： Vahid Zal Hassan Moslemi Naeini Ahmad Reza Bahramian Behnam abbaszadeh Faculty of Mechanical Engineering Tarbiat ModaresUniversity Tehran Iran Faculty of Chemical Engineering Tarbiat ModaresUniversity Tehran Iran

Blanking is one of the high speed processes to produce fiat products from sheets economically. In order to expand this process to new materials, the blanking of polyvinyl chloride （PVC）/fiberglass thermoplastic com- posite laminates and composite/aluminum hybrid laminates was investigated. The laminates were produced by the film stacking procedure and then blanked by circular die and punches. The blanking process was done in two levels of clearance including 4% and 8% of the laminates thickness, two levels of punch speed including 40 mm/min and 200 mm/min and at two levels of temperature （room tem- perature and 80 ℃） for both composite and hybrid laminates. The effects of the parameters on the maximum blanking force, cutting energy, and quality and precision of sheared edges were studied. Cutting mechanism for blanking in different conditions was explained. It was concluded that at room temperature, blanked composite and hybrid laminates had a high quality of sheared edges but at elevated temperature, although the maximum blanking force was reduced, the quality of sheared edge was reduced significantly.

关键词： Composite laminate Hybrid laminate Blanking Fiberglass Polyvinyl chloride (PVC)

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