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Acta Metallurgica Sinica(English Letters) 2014年第6期27卷 1018-1030页

作者： r. Sridhar K. Devendranath ramkumar N. Arivazhagan School of Mechanical & Building Sciences VIT University Saraswathy Velu College of Engineering

The dissimilar combinations of Inconel 625 and duplex stainless steel SAF 2205 obtained from manual GTA welding process employing Er2209 and ErNi CrMo-3 filler metals have been investigated. Formation of secondary phases at the HAZ of Inconel 625 and grain coarsening at the HAZ of SAF 2205 were witnessed while using these filler wires. The average hardness of Er2209 weldments was found to be greater than ErNi CrMo-3 weld. Tensile fracture was observed at the weld zones for both the fillers. Impact test trials showed brittle mode of fracture on employing Er2209 filler and mixed（ductile–brittle） mode of fracture while using ErNi CrMo-3 filler. Further optical microscopy and SEM/EDS analysis were carried out across the weldments to investigate the structure–property relationships.

关键词： Inconel 625 Duplex stainless steel SAF 2205 Dissimilar metal welding Microstructure Mechanical characterization

rapid Identification of rice Samples Using an Electronic Nose

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Journal of Bionic Engineering 2009年第3期6卷 290-297页

作者： John Westbrook W.C.Hoffmann r.E.Lacey USDA-ArS College Station Department of Biological and Agricultural Engineering Texas A&M UniversityCollege Station

Four rice samples of long grain type were tested using an electronic nose (Cyranose-320).Samples of 5 g of each variety of rice were placed individually in vials and were analyzed with the electronic nose unit consisting of 32 polymer *** Cyranose-320 was able to differentiate between varieties of *** chemical composition of the rice odors for differentiating rice samples needs to be *** optimum parameter settings should be considered during the Cyranose-320 training process especially for multiple samples,which are helpful for obtaining an accurate training model to improve identification ***,it is necessary to investigate the E-nose sensor selection for obtaining better classification accuracy.A re- duced number of sensors could potentially shorten the data processing time,and could be used to establish an application pro- cedure and reduce the cost for a specific electronic *** research is needed for developing analytical procedures that adapt the Cyranose-320 as a tool for testing rice quality.

关键词： rice grain identification electronic nose data analysis pattern recognition

Analytical solution of multiple moving cracks in functionally graded piezoelectric strip

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Applied Mathematics and Mechanics(English Edition) 2015年第6期36卷 777-792页

作者： r.BAGHErI M.AYAToLLAHI S.M.MoUSAVI Faculty of Engineering University of Zanjan Department of Civil and Structural Engineering Aalto University

The dynamic behaviors of several moving cracks in a functionally graded piezoelectric （FGP） strip subjected to anti-plane mechanical loading and in-plane elec- trical loading are investigated. For the first time, the distributed dislocation technique is used to construct the integral equations for FGP materials, in which the unknown variables are the dislocation densities. With the dislocation densities, the field intensity factors are determined. Moreover, the effects of the speed of the crack propagation on the field intensity factors are studied. Several examples are solved, and the numerical results for the stress intensity factor and the electric displacement intensity factor are presented graphically finally.

关键词： functionally graded piezoelectric dislocation density moving crack strip

Performance analysis of new word weighting procedures for opinion mining

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Frontiers of Information Technology & Electronic Engineering 2016年第11期17卷 1186-1198页

作者： G.r.BrINDHA P.SWAMINATHAN B.SANTHI School of Computing SASTRA University

The proliferation of forums and blogs leads to challenges and opportunities for processing large amounts of information. The information shared on various topics often contains opinionated words which are qualitative in nature. These qualitative words need statistical computations to convert them into useful quantitative data. This data should be processed properly since it expresses opinions. Each of these opinion bearing words differs based on the significant meaning it conveys. To process the linguistic meaning of words into data and to enhance opinion mining analysis, we propose a novel weighting scheme, referred to as inferred word weighting(IWW). IWW is computed based on the significance of the word in the document(SWD) and the significance of the word in the expression(SWE) to enhance their performance. The proposed weighting methods give an analytic view and provide appropriate weights to the words compared to existing methods. In addition to the new weighting methods, another type of checking is done on the performance of text classification by including stop-words. Generally, stop-words are removed in text processing. When this new concept of including stop-words is applied to the proposed and existing weighting methods, two facts are observed:(1) Classification performance is enhanced;(2) The outcome difference between inclusion and exclusion of stop-words is smaller in the proposed methods, and larger in existing methods. The inferences provided by these observations are discussed. Experimental results of the benchmark data sets show the potential enhancement in terms of classification accuracy.

关键词： Inferred word weight opinion mining Supervised classification Support vector machine(SVM) Machine learning

Piezoelectric Thin Film:Fabrication,Properties and Applications

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Piezoelectric Thin Film:Fabrication,Properties and Applicati...

Nonlinear vibration analysis of fractional viscoelastic Euler–Bernoulli nanobeams based on the surface stress theory

第二届全国压电和声波理论及器件技术研讨会

作者： Long Wu~* (Department of Electronic Engineering,Far East University,Taiwan,r.o.C.)

In this paper,the fabrication processes,properties and applications of three types piezoelectric thin film:AlN,Zno and PZT are *** different fabrication method and substrate,the piezoelectric thin film had different *** and Zno are polar materials with hexagonal wurtzite crystal *** films of these compounds can possess a strong oriented polycrystalline fibered structure,and the key problem is to control the film texture,together with physical properties,on various electroded *** is perovskite-type ferroelectric materials,it also polar(and piezoelectric),but in these materials the polarization can be switched and reversed by an applied electric field,and it require higher growth temperatures(500-700℃) to stabilize the desired ferroelectric phase. AlN and Zno posses material properties that make them suitable for current front-end filters for global positioning system(GPS) receivers and rF components in current personal communications systems (PCS) ***,the low electromechanical coupling in AlN and Zno leads to low-bandwidth filters(o meet the requirements for broad-band access and large data *** is apparent that materials with higher coupling coefficient are required beyond AlN unless some other means of bandwidth enhancement are used,such as integral inductors to pull the resonators to higher effective *** bandwidth is well short of the requirement for full bandwidth filters in the PCS(3.2%) and ISM(3.5%) bands,and suggest that Zno might be an ideal piezoelectric for use in these wider bandwidth ***,other factors must be considered such as intrinsic Q at high frequencies and potential fabrication *** materials in the PZT series can have high electromechanical coupling coefficients but their draw back is the high acoustic losses at microwave frequencies.

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Acta Mechanica Solida Sinica 2017年第4期30卷 416-424页

作者： M.Faraji oskouie r.Ansari F.Sadeghi Department of Mechanical Engineering University of Guilan

The nonlinear vibrations of viscoelastic Euler-Bernoulli nanobeams are studied using the fractional calculus and the Gurtin-Murdoch theory. Employing Hamilton＇s principle, the governing equation considering surface effects is derived. The fractional integro-partial differential governing equation is first converted into a fractional-ordinary differential equation in the time domain using the Galerkin scheme. Thereafter, the set of nonlinear fractional time-dependent equations expressed in a state-space form is solved using the predictorcorrector method. Finally, the effects of initial displacement, fractional derivative order, viscoelasticity coefficient, surface parameters and thickness-to-length ratio on the nonlinear time response of simply-supported and clamped-free silicon viscoelastic nanobeams are investigated.

关键词： Fractional calculus Viscoelastic nanobeam Nonlinear vibrations

Practical optimization of deployable and scissor-like structures using a fast GA method

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Frontiers of Structural and Civil Engineering 2019年第3期13卷 557-568页

作者： M.SALAr M.r.GHASEMI B.DIZANGIAN Department of Civil Engineering University of Sistan and BaluchestanZahedanIran Department of Civil Engineering Velayat UniversityIranshahrIran

This paper addresses practical sizing optimization of deployable and scissor-like structures from a new point of *** structures have been recently highly regarded for beauty,lightweight,determine behavior,proper performance against lateral loads and the ability of been compactly *** this time,there is a few studies done considering practical optimization of these *** considered here includes wind and gravity *** foldable scissor-like structures,connections have a complex *** this reason,in this study,the authors used the ABAQUS commercial package as an analyzer in the optimization *** made the obtained optimal solutions highly reliable from the point of view of applicability and construction ***,to do optimization task,a fast genetic algorithm method,which has been recently introduced by authors,was *** results show that despite less weight for aluminum models than steel models,aluminum deployable structures are not affordable because they need more material than steel structures and cause more environmental damage.

关键词： optimization scissor-like structures deployable structures genetic algorithm ABAQUS

orientation effect on ground motion measurement for Mexican subduction earthquakes

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Earthquake Engineering and Engineering Vibration 2009年第1期8卷 1-16页

作者： H.P. Hong A. Pozos-Estrada r. Gomez Department of Civil and Environmental Engineering University of Western Ontario Canada N6A 5B9 Institute of Engineering National Autonomous University of Mexico Mexico D.F.

The existence of the principal directions of the ground motion based on Arias intensity is well-known. These principal directions do not necessarily coincide with the orientations of recording sensors or with the orientations along which the ground motion parameters such as the peak ground acceleration and the pseudo-spectral acceleration （PSA） are maximum. This is evidenced by the fact that the maximum PSA at different natural vibration periods for horizontal excitations do not correspond to the same orientation. A recent analysis carried out for California earthquake records suggests that an orientation-dependent ground motion measurement for horizontal excitations can be developed. The main objective of this study is to investigate and provide seismic ground motion measurements in the horizontal plane, including bidirectional horizontal ground motions, for Mexican interplate and inslab earthquake records. Extensive statistical analyses of PSA are conducted for the assessment. The analysis results suggest that similar to the case of California records, the average behavior of the ratio of the PSA to the maximum resulting PSA can be approximated by a quarter of an ellipse in one quadrant; and that the ratio can be considered to be independent of the value of the maximum resulting PSA, earthquake magnitude, earthquake distance and the focal depth. Sets of response ratios and attenuation relationships that can be used to represent a bidirectional horizontal ground motion measurement for Mexican interplate and inslab earthquakes were also developed.

关键词： orthogonal horizontal excitations bidirectional ground motion measure attenuation relationship pseudospectral acceleration (PSA) response ratio Mexican earthquake

Swelling-induced finite bending of functionally graded pH-responsive hydrogels:a semi-analytical method

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Applied Mathematics and Mechanics(English Edition) 2019年第5期40卷 679-694页

作者： M.SHoJAEIFArD M.r.BAYAT M.BAGHANI School of Mechanical Engineering College of Engineering University of Tehran

recently, pH-sensitive hydrogels have been utilized in the diverse applications including sensors, switches, and actuators. In order to have continuous stress and deformation ?elds, a new semi-analytical approach is developed to predict the swelling induced?nite bending for a functionally graded(FG) layer composed of a pH-sensitive hydrogel,in which the cross-link density is continuously distributed along the thickness direction under the plane strain condition. Without considering the intermediary virtual reference,the initial state is mapped into the deformed con?guration in a circular shape by utilizing a total deformation gradient tensor stemming from the inhomogeneous swelling of an FG layer in response to the variation of the pH value of the solvent. To enlighten the capability of the presented analytical method, the ?nite element method(FEM) is used to verify the accuracy of the analytical results in some case studies. The perfect agreement con-?rms the accuracy of the presented method. Due to the applicability of FG pH-sensitive hydrogels, some design factors such as the semi-angle, the bending curvature, the aspect ratio, and the distributions of deformation and stress ?elds are studied. Furthermore, the tangential free-stress axes are illustrated in deformed con?guration.

关键词： pH-sensitive hydrogel functionally graded(FG)layer finite bending semianalytical solution finite element method(FEM)

Damage detection on framed structures: modal curvature evaluation using Stockwell Transform under seismic excitation

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Earthquake Engineering and Engineering Vibration 2015年第2期14卷 265-274页

作者： r.Ditommaso F.C.Ponzo G.Auletta Department of Structures Geotechnics Engineering Geology University of Basilicata School of Engineering University of Basilicata

The key parameters for damage detection and localization are eigenfrequencies, related equivalent viscous damping factors and mode shapes. The classical approach is based on the evaluation of these structural parameters before and after a seismic event, but by using a modern approach based on time-frequency transformations it is possible to quantify these parameters throughout the ground shaking phase. In particular with the use of the S-Transform, it is possible to follow the temporal evolution of the structural dynamics parameters before, during and after an earthquake. In this paper, a methodology for damage localization on framed structures subjected to strong motion earthquakes is proposed based on monitoring the modal curvature variation in the natural frequency of a structure. Two examples of application are described to illustrate the technique: Computer simulation of the nonlinear response of a model, and several laboratory(shaking table) tests performed at the University of Basilicata(Italy). Damage detected using the proposed approach and damage revealed via visual inspections in the tests are compared.

关键词： damage detection S-transform band-variable fi lter