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Reliability analysis of extended generalized inverted exponential distribution with applications

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Journal of Systems Engineering and Electronics 2016年第2期27卷 484-492页

作者： Arwa m.Alshangiti m.Kayid m.Almulhim Department of Statistics and Operations Research College of Science King Saud University

A general version of the inverted exponential distribution is introduced, studied and analyzed. This generalization depends on the method of marshall-Olkin to extend a family of distributions. Some statistical and reliability properties of this family are studied. In addition, numerical estimation of the maximum likelihood estimate（mLE） parameters are discussed in details. As an application, some real data sets are analyzed and it is observed that the presented family provides a better fit than some other known distributions.

关键词： inverted exponential distribution reliability properties statistical properties maximum likelihood estimates applications

Head-on collision between single-and multi-soliton heavy ion acoustic waves in multi-ion plasmas

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Plasma Science and Technology 2019年第9期21卷 58-72页

作者： m S ALAm m R TALUKDER Department of mathematics Chittagong University of Engineering and Technology Chittagong-4349 Bangladesh Plasma Science and Technology Lab Department of Electrical and Electronic Engineering University of Rajshahi Rajshahi-6205 Bangladesh

Head-on collisions among the single-and multi-soliton’s heavy ion acoustic waves(HIAWs) of multi-ion plasma are studied. The plasma consists of adiabatic positively charged inertial heavy ions, Boltzmann energy distributed light ions and kappa energy distributed electrons. The extended poincaré-Lighthill-Kuo(e PLK) method is applied for the derivation of two-sided Korteweg–de Vries(KdV) equations(KdVEs). The KdV single-soliton solutions(KdVSSs) are determined using the hyperbolic secant method and the KdV multi-soliton solutions(KdVmSs)are obtained using the Hirota method. The effects of superthermality of electrons, temperature ratios of electron to light ion and heavy ion to electron, and the density ratio of electron to heavy ion on phase shifts are investigated for the head-on collisions between two-soliton HIAWs. The effects of plasma parameters on angular frequency, phase speed, production of multi-soliton structures, and the head-on collisions among single-, double-, triple-, quadruple-, and quintuplesolitons are also studied.

关键词： HIAWs multi-soliton kappa-distribution ePLK method Hirotta's method multi-ion

Nonlinear buckling and postbuckling behavior of cylindrical shear deformable nanoshells subjected to radial compression including surface free energy effects

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Acta mechanica Solida Sinica 2017年第2期30卷 209-222页

作者： S.Sahmani m.m.Aghdam m.Bahrami Department of mechanical Engineering Amirkabir University of Technology P.O. Box 15875-4413 Tehran Iran

The objective of the present investigation is to predict the nonlinear buckling and postbuckling characteristics of cylindrical shear deformable nanoshells with and without initial imperfection under hydrostatic pressure load in the presence of surface free energy *** this end, Gurtin-murdoch elasticity theory is implemented into the irst-order shear deformation shell theory to develop a size-dependent shell model which has an excellent capability to take surface free energy effects into account. A linear variation through the shell thickness is assumed for the normal stress component of the bulk to satisfy the equilibrium conditions on the surfaces of nanoshell. On the basis of variational approach and using von Karman-Donnell-type of kinematic nonlinearity, the non-classical governing differential equations are derived. Then a boundary layer theory of shell buckling is employed incorporating the effects of surface free energy in conjunction with nonlinear prebuckling deformations, large delections in the postbuckling domain and initial geometric imperfection. Finally, an eficient solution methodology based on a two-stepped singular perturbation technique is put into use in order to obtain the critical buckling loads and postbuckling equilibrium paths corresponding to various geometric parameters. It is demonstrated that the surface free energy effects cause increases in both the critical buckling pressure and critical end-shortening of a nanoshell made of silicon.

关键词： Nanoscale structures Size effect Nonlinear buckling Surface free energy Boundary layer theory

Diagnostic Study of an Fe-Ni Alloy Plasma Generated by the Fundamental (1064 nm) and Second (532 nm) Harmonics of an Nd: YAG Laser

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Plasma Science and Technology 2013年第5期15卷 397-402页

作者： m.HANIF m.SALIK m. A. BAIG mCS National University of Sciences & Technology (NUST) School of Science Beijing Jiaotong University National Center for Physics Quaid-i-Azam University Campus

We studied the spatial evolution of the Fe-Ni plasma generated by the fundamental （1064 nm） and second （532 nm） harmonics of a Q-switched Nd： YAG laser. The experimentally observed line profiles of the neutral iron （Fe I） have been used to extract the plasma temperature （T e ） using the Boltzmann plot method, whereas the electron number density （N e ） has been deter- mined from the Stark broadening. In addition, we studied the spatial behavior of T e and N e with the variation of laser energy for iron plasma by placing the target material （iron-nickel alloy） in air at atmospheric pressure for both modes of the Nd： YAG laser.

关键词： iron plasma laser ablation electron temperature electron number density

Stochastic seismic response of multi-layered soil with random layer heights

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Earthquake Engineering and Engineering Vibration 2010年第2期9卷 213-221页

作者： m.Badaoui m.K.Berrah A.mébarki Université Paris-Est Laboratoire Modélisation et Simulation Multi Echelle Ecole Nationale Polytechnique

This paper deals with the effect of layer height randomness on the seismic response of a layered soil. These parameters are assumed to be lognormal random variables. The analysis is carried out via monte Carlo simulations coupled with the stiffness matrix method. A parametric study is conducted to derive the stochastic behavior of the peak ground acceleration and its response spectrum,the transfer function and the amplification factors. The input soil characteristics correspond to a site in mexico City and the input seismic accelerations correspond to the Loma Prieta earthquake. It is found that the layer height heterogeneity causes a widening of the frequency content and a slight increase in the fundamental frequency of the soil profile,indicating that the resonance phenomenon is a concern for a large number of structures. Variation of the layer height randomness acts as a variation of the incident angle,i.e.,a decrease of the amplitude and a shift of the resonant frequencies.

关键词： random layer heights layered soil seismic acceleration lognormal distribution amplification factors mexico City

Health monitoring of time-varying stochastic structures by latent components and fuzzy expert system

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Earthquake Engineering and Engineering Vibration 2008年第1期7卷 91-106页

作者： m. m. Ettefagh m. H. Sadeghi Vibration and modal Analysis Laboratory Department of Mechanical Engineering University of Tabriz Tabriz 51666 Iran

In this paper, a novel parametric model-based decomposition method is proposed for structural health monitoring of time-varying structures. For this purpose, the advanced Functional-Series Time-dependent Auto Regressive moving Average （FS-TARmA） technique is used to estimate the parameters and innovation variance used in the parametric signal decomposition scheme. Additionally, a unique feature extraction and reduction method based on the decomposed signals, known as Latent Components （LCs）, is proposed. To evaluate the efficiency of the proposed method, numerical simulation and an experimental study in the laboratory were conducted on a time-varying structure, where various types of damage were introduced. The Fuzzy Expert System （FES） was used as a classification toot to demonstrate that the proposed method successfully identifies different structural conditions when compared with other methods based on non-reduced and ordinary feature extraction.

关键词： parametric modeling signal decomposition feature extraction/reduction fuzzy classification

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)

A computational study of a capsule lateral migration in microchannel flow

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Acta mechanica Sinica 2013年第4期29卷 513-525页

作者： m.Navidbakhsh m.Rezazadeh Department of mechanical Engineering Iran University of Science and Technology

A numerical method is used to model a capsule migration in a microchannel with small Reynolds number Re = 0.01. The capsule is modeled as a liquid drop sur- rounded by a neo-Hookean elastic membrane. The numer- ical model combines immersed boundary with lattice Boltz- mann method （IB-LBm）. The LBm is used to simulate fixed Cartesian grid while the IBm is utilized to implement the fluid-structure interaction by a set of Lagrangian moving grids for the membrane. The effect of shear elasticity and bending stiffness are both considered. The results show the significance of elastic modulus and initial lateral position on deformation and morphological properties of a circular cap- sule. The wall effect becomes stronger as the capsule ini- tial position gets closer to the channel wall. As the elastic modulus of membrane increases, the capsule undergoes less pronounced deformation and velocity in direction x is de- creased, thus, the capsule motion is slower than the back- ground flow. The best agreement between the present model and experiments for migration velocity takes place for the capsule with normal to moderate membrane elastic modulus. The results are in good agreement with experiment study of Coupier et al. and previous numerical studies. Therefore, the IB-LBm can be employed to make prediction in vitro and in vivo studies of capsule deformation.

关键词： Capsule. Lateral migration. Lattice Boltzmann.Immersed boundary ~ Deformation ~ Initial position

Leaching of complex sulphide concentrate in acidic cupric chloride solutions

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中国有色金属学会会刊：英文版 2007年第2期17卷 423-428页

作者： m.TCHOUmOU m.ROYNETTE Faculty of Science Marien Ngouabi University Laboratory of Applied Electrochemistry EHICS Louis Pasteur University

The chemical analysis of a complex sulphide concentrate by emission spectrometry and X-ray diffraction shows that it contains essentially copper, lead, zinc and iron in the form of chalcopyrite, sphalerite and galena. A small amount of pyrite is also present in the ore but does not be detected with X-ray diffraction. The cupric chloride leaching of the sulphide concentrate at various durations and solid/liquid ratios at 100 ℃ shows that the rate of dissolution of the ore is the fastest in the first several hours, and after 12 h it does not evolve significantly. If oxygen is excluded from the aqueous cupric chloride solution during the leaching experiment at 100 ℃, the pyrite in the ore will not be leached. The determination of principal dissolved metals in the leaching liquor by flame atomic absorption spectrometry, and the chemical analysis of solid residues by emission spectrometry and X-ray diffraction allow to conclude that the rate of dissolution of the minerals contained in the complex sulphide concentrate are in the order of galena >sphalerite>chalcopyrite.

关键词：酸性氯化铜溶液复合硫化物精矿浸出溶出速度