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Ef.ect of.Welding Parameters on Dilution and Weld Bead Geometry in Cladding

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Journal of.Materials Science & Technology 2007年第6期23卷 817-822页

作者： M.Nouri A.Abdollah-zadeh f.Malek Department of.Materials Engineering Tarbiat Modares UniversityP.O.Box 14115-143TehranIran

The ef.ect of.pulsed gas metal arc welding （GMAW） variables on the dilution and weld bead geometry in cladding X65 pipeline steel with 316L stainless steel was studied. Using a f.ll f.ctorial method, a series of.experiments were carried out to know the ef.ect of.wire f.ed rate, welding speed, distance between gas nozzle and plate, and the vertical angle of.welding on dilution and weld bead geometry. The f.ndings indicate that the dilution of.weld metal and its dimension i.e. width, height and depth increase with the f.ed rate, but the contact angle of.the bead decreases f.rst and then increases. Meantime, welding speed has an opposite ef.ect except f.r dilution. There is an interaction ef.ect between welding parameters at the contact angle. The results also show f.rehand welding or decreasing electrode extension decrease the angle of.contact. f.nally, a mathematical model is contrived to highlight the relationship between welding variables with dilution and weld bead geometry.

关键词： Pulsed gas metal arc welding (GMAW) Cladding Weld Bead Dilution f.ll f.ctorial design

Toward the Design of.Multi Asymmetric Surf.ce Dielectric Barrier Discharge (ASDBD) Actuators

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Plasma Science and Technology 2015年第1期17卷 56-63页

作者： Massiel zadeh V.ROHANI f.CAUNEAU f.f.BRY L.f.LCHERI Centre f.r Processes Renewable Energies and Energy Systems-PERSEE- MINES ParisTech

This paper investigates the electrical and mechanical behaviors of.a single-ASDBD actuator and a two-ASDBD one supplied in sinusoidal mode（1-10 kHz）.The main objective of.our research is to determine the optimum f.equency values f.r the f.nction of.these actuators with a given power *** this purpose,we determine the electrical power density input to the actuators versus f.equency through two methods：i） a semi-theoretical method,based on an impedance calculation,and ii） an experimental method,based on direct electrical *** methods show that the addition of.a second ASDBD changes the resonance f.equency value of.the actuator by moving it towards low *** characterizing the aerodynamic mobile layer structure induced by the single-ASDBD actuator,we analyze experimentally the mechanical response of.a two-ASDBD actuator as a f.nction of.the inter-ASDBD *** experiments demonstrate that the induced electric wind velocity and the electro-mechanical yield of.a twoASDBD actuator reach a maximum value f.r an optimum inter-ASDBD distance,which is a usef.l value f.r the design of.highly ef.icient multi-ASDBD actuators.

关键词： ASDBD actuator resonance f.equency electro-mechanical yield

A magnetic adsorbent based on salicylic acid-immobilized magnetite nano-particles f.r pre-concentration of.Cd(II) ions

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f.ontiers of.Chemical Science and Engineering 2021年第2期15卷 450-459页

作者： Hossein Abdolmohammad-zadeh Arezu Salimi Analytical Spectroscopy Research Lab Department of ChemistryFaculty of SciencesAzarbaijan Shahid Madani UniversityTabriz ***Iran

In this research,an eco-f.iendly magnetic adsorbent based on f._(3)O_(4)/salicylic acid nanocomposite was f.bricated using a f.cile one-pot co-precipitation *** crystalline and morphological characterization of.the prepared nanocomposite was perf.rmed by f.eld emission scanning electron microscopy,X-ray dif.raction,and f.urier transf.rm inf.ared *** nanocomposite was employed as a magnetic solid-phase extraction agent f.r separation of.Cd(II)ions f.om synthetic *** experimental f.ctors af.ecting the extraction ef.iciency were investigated and *** elution with acetic acid(pH 3.5),the pre-concentrated analyte was quantif.ed by f.ame atomic absorption *** optimal conditions,a linear calibration graph was achieved in the concentration range of.0.2–30 ng·mL^(−1) with a determination coef.icient(R^(2))of.*** detection limit,the enhancement f.ctor,inter-and intra-day relative standard deviations(f.r six consecutive extractions at the concentration level of.10 ng·mL^(−1))were 0.04 ng·mL^(−1),100,2.38%and 1.52%,*** evaluate the accuracy of.the method,a certif.ed ref.rence material(NIST SRM 1643e)was analyzed,and there was a good agreement between the certif.ed and the measured *** was successf.lly utilized to determine cadmium in industrial wastewater samples and the attained relative recovery values were between 96.8%and 103.2%.

关键词： cadmium magnetic solid-phase extraction f._(3)O_(4)nanoparticles f._(3)O_(4)/salicylic acid nanocomposite f.ame atomic absorption spectrometry

An ef.icient aerodynamic shape optimization of.blended wing body UAV using multi-f.delity models

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Chinese Journal of.Aeronautics 2018年第6期31卷 1165-1180页

作者： Parviz MOHAMMAD zadeh Mohsen SAYADI f.culty of.New Sciences and Technologies University of Tehran

This paper presents a novel optimization technique f.r an ef.icient multi-f.delity model building approach to reduce computational costs f.r handling aerodynamic shape optimization based on high-f.delity simulation models. The wing aerodynamic shape optimization problem is solved by dividing optimization into three steps—modeling 3D（high-f.delity） and 2D（lowf.delity） models, building global meta-models f.om prominent instead of.all variables, and determining robust optimizing shape associated with tuning local meta-models. The adaptive robust design optimization aims to modif. the shape optimization process. The suf.icient inf.lling strategy—known as adaptive unif.rm inf.lling strategy—determines search space dimensions based on the last optimization results or initial point. f.llowing this, 3D model simulations are used to tune local meta-models. f.nally, the global optimization gradient-based method—Adaptive f.lter Sequential Quadratic Programing（Af.QP） is utilized to search the neighborhood f.r a probable optimum point. The ef.ectiveness of.the proposed method is investigated by applying it, along with conventional optimization approach-based meta-models, to a Blended Wing Body（BWB） Unmanned Aerial Vehicle（UAV）. The drag coef.icient is def.ned as the objective f.nction, which is subjected to minimum lif. coef.icient bounds and stability constraints. The simulation results indicate improvement in meta-model accuracy and reduction in computational time of.the method introduced in this paper.

关键词： Adaptive f.lter sequential quadratic programing(Af.QP) Adaptive robust meta-model Aerodynamic shape optimization Blended wing body(BWB) Move limit strategy Unmanned aerial vehicle(UAV)

Teaching the User By Learning f.om the User:Personalizing Movement Control in Physical Human-robot Interaction

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IEEE/CAA Journal of.Automatica Sinica 2017年第4期4卷 704-713页

作者： Ali Saf.vi Mehrdad H.zadeh Department of.Electrical and Computer Engineering Kettering UniversityFlintMI 48504USA

This paper proposes a novel approach f.r physical human-robot interactions(pHRI), where a robot provides guidance f.rces to a user based on the user perf.rmance. This f.amework tunes the f.rces in regards to behavior of.each user in coping with dif.erent tasks, where lower perf.rmance results in higher intervention f.om the robot. This personalized physical human-robot interaction(p2HRI) method incorporates adaptive modeling of.the interaction between the human and the robot as well as learning f.om demonstration(Lf.) techniques to adapt to the users' perf.rmance. This approach is based on model predictive control where the system optimizes the rendered f.rces by predicting the perf.rmance of.the user. Moreover, continuous learning of.the user behavior is added so that the models and personalized considerations are updated based on the change of.user perf.rmance over time. Applying this f.amework to a f.eld such as haptic guidance f.r skill improvement, allows a more personalized learning experience where the interaction between the robot as the intelligent tutor and the student as the user,is better adjusted based on the skill level of.the individual and their gradual improvement. The results suggest that the precision of.the model of.the interaction is improved using this proposed method,and the addition of.the considered personalized f.ctors to a more adaptive strategy f.r rendering of.guidance f.rces.

关键词： Haptic guidance learning f.om demonstration(Lf.) personalized physical human-robot interaction(p2HRI) user perf.rmance

ECG beat classif.cation using particle swarm optimization and support vector machine

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f.ontiers of.Computer Science 2014年第2期8卷 217-231页

作者： Ali KHAZAEE A. E. zadeh Department of.Electrical Engineering Bojnourd Branch Islamic Azad University Bojnourd *** Iran f.culty of.Electrical and Computer Engineering B abol University of Technology Bobo*** Iran

In this paper, we propose a novel ECG arrhythmia classif.cation method using power spectral-based f.atures and support vector machine （SVM） classif.er. The method extracts electrocardiogram＇s spectral and three timing inter- val f.atures. Non-parametric power spectral density （PSD） estimation methods are used to extract spectral f.atures. The proposed approach optimizes the relevant parameters of.SVM classif.er through an intelligent algorithm using parti- cle swarm optimization （PSO）. These parameters are： Gaus- sian radial basis f.nction （GRBf. kernel parameter o- and C penalty parameter of.SVM classif.er. ECG records f.om the MIT-BIH arrhythmia database are selected as test data. It is observed that the proposed power spectral-based hybrid par- ticle swarm optimization-support vector machine （SVMPSO） classif.cation method of.ers signif.cantly improved perf.r- mance over the SVM which has constant and manually ex- tracted parameter.

关键词： ECG arrhythmia classif.cation SVM PSO op-timization PSD

Ef.ect of.Delay Time on Microstructural Evolution during Warm Rolling of.Ti-Nb-If.Steel

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Journal of.Materials Science & Technology 2004年第1期20卷 86-88页

作者： A. Najaf.-zadeh R.Ebrahimi Department of.Materials Engineering Isfahan University of Technology Isfahan 84154 IranDepartment of Materials Engineering Isfahan University of Technology Isfahan 84154 Iran

The ef.ect of.delay time with constant f.rst f.nishing pass temperature (800℃) has been investigated by means of.multi-pass torsion tests on Ti-Nb-If.steel. All the tests have been carried out at a strain rate of.2 s-1 with 11 passes and 0.3 strain each pass. During the f.nal pass, dynamic recrystallization occurs to a degree that depends on the delay time. In short interpass time (1 s) and at these temperatures (T≤800℃) there is not enough time to start static recrystallization, theref.re, accumulation of.strain occurs and af.er some passes, strain reaches a critical strain f.r starting dynamic recrystallization. In this study, the changes of.mean f.ow stress during each pass and also the microstructural observation conf.rms that dynamic recrystallization occurs af.er some passes in f.rrite phase of.this steel. The stress-strain curves with constant temperature obtained by using a kinetic model and compensation of.the increasing mean f.ow stress with decreasing temperature. Thus, this result also conf.rms that dynamic recrystallization occurs in warm rolling of.this If.steel.

关键词： Warm rolling Perrite rolling Thermomechanical processing If.steels

Thermomechanical Behavior of.Ti-6Al-4V Alloy

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Journal of.Materials Science & Technology 2003年第3期19卷 217-220页

作者： K.f.rmanesh A.Najaf.-zadeh Dept.of.Materials Engineering Isfahan University of TechnologyIsfahan 85154IranDept.of Materials EngineeringIsfahan University of TechnologyIsfahan 85154Iran

Ti-6AI-4V, among the Ti alloys, is the most widely used. In the present work, the behavior of.Ti-6AI-4V alloy has been investigated by the uniaxial hot isothermal compression tests and a series of.dilatometric experiments were also carried out to determine the transf.rmation temperatures at dif.erent cooling rates. Specimens f.r hot compression tests were homogenized at 1050℃ f.r 10 min and then quickly cooled to dif.erent straining temperatures f.om 1050 to 850℃. Cooling rates were chosen f.st enough to prevent high temperature transf.rmation during cooling. Compression tests were conducted at temperatures f.om 1050 to 850℃ in steps of.50℃ at constant true strain rates of.10-3 or 10-2 s-1. The apparent activation energy f.r compression in two-phase region was calculated 420 kJ·mol-1. Partial globularization of.a phase was observed in the specimen def.rmed at low strain rates and at temperatures near the transf.rmation zone and annealed af.er def.rmation.

关键词： Titanium alloy Hot pressing Ti-6A1-4V Dilatometry

Ef.ect of.Strain Rate on the f.rrite Grain Ref.nement in a Low Carbon Nb-Ti Microalloyed Steel during Low Temperature Def.rmation

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Journal of.Materials Science & Technology 2005年第6期21卷 851-855页

作者： B.Eghbali A.Abdollah-zadeh Department of.Materials Engineering Tarbiat Modarres University P.O. Box 14115-143 Tehran Iran

Grain ref.nement is one of.the ef.ective methods to develop new generation low carbon microalloyed steels possessing excellent combination of.mechanical properties. The microstructural evolution and f.rrite grain ref.nement at the def.rmation temperature of.865℃, above Ar3, with dif.erent strain rates were investigated using single pass isothermal hot compression experiments f.r a low carbon Nb-Ti microalloyed steel. The physical processes that occurred during def.rmation were discussed by observing the optical microstructure and analyzing the true stress-true strain responses. At strain rates of.0.001 and 0.01s^-1, there is no evidence of.work hardening behavior during hot def.rmation and strain-induced transf.rmation （SIT） leads to dynamic f.ow sof.ening in f.ow curves. Optical microscopy observation shows that ultraf.ne and equiaxed f.rrite with grain sizes of.2μm can be obtained by applying def.rmation with strain rate of.0.1 s^-1 due to SIT just af.er def.rmation. f.rthermore, increasing the strain rate f.om 0.001 to 0.1 s^-1 reduces both the grain size of.the equiaxed f.rrite and the amount of.def.rmed f.rrite.

关键词： Low carbon microalloyed steel Hot compression Grain ref.nement Strain induced transf.rmation