نتایج جستجو برای: rayleigh wave group velocity for each source

تعداد نتایج: 10938287  

2014
B. P. Barik

Problems of wave propagation in perfect magnetoelastic conductors have been studied, among others, by Knopoff [1], Dunkin and Eringen [2], Yu and Tang [3], Paria [4]. Kalishki and Rogula [5] have discussed Rayleigh waves in a semi-infinite perfect electrical conductor for a single component magnetic field. The propagation of Rayleigh-type magnetoelastic waves in a semi-infinite perfect electric...

2012

W reflection seismology, surface waves or ground roll, are often considered a form of unwanted sourcegenerated noise. Unlike body waves, surface waves propagate exclusively in the lateral direction and are virtually insensitive to structure deeper than one wavelength. For a nominal frequency of 5 Hz and phase velocity of 500 m/s, this means that a surface wave of the Rayleigh or Love type only ...

2017
Shuzeng Zhang Xiongbing Li Hyunjo Jeong

A theoretical model, along with experimental verification, is developed to describe the generation, propagation and reception of a Rayleigh wave using angle beam wedge transducers. The Rayleigh wave generation process using an angle beam wedge transducer is analyzed, and the actual Rayleigh wave sound source distributions are evaluated numerically. Based on the reciprocity theorem and consideri...

2011
Shamachary Sathish Richard W. Martin Theodore E. Matikas

In a Scanning Acoustic Microscope (SAM) amplitude of focused acoustic beam reflected by a sample is utilized to produce acoustic images and to measure local elastic property for effective nondestructive characterization of materials. The most important acoustic rays involved in both imaging and quantitative measurements in an acoustic lens are shown in Fig.l. The extra contribution to the refle...

2017
Matthew M. Haney Victor C. Tsai

The inversion of Rayleigh-wave dispersion curves is a classic geophysical inverse problem. We have developed a set of MATLAB codes that performs forward modeling and inversion of Rayleigh-wave phase or group velocity measurements. We describe two different methods of inversion: a perturbational method based on finite elements and a nonperturbational method based on the recently developed Dix-ty...

2012
B. SINGH J. SINGH

The governing equations of generalized magneto-thermoelasticity with hydrostatic initial stress are solved for surface wave solutions. The particular solutions in the half-space are applied to the boundary conditions at the free surface of the half-space to obtain the frequency equation of Rayleigh wave. The frequency equation is approximated for small thermal coupling and small reduced frequen...

In this work, the problem of Rayleigh wave propagation is considered in the context of the theory of thermoelastic diffusion. The formulation is applied to a homogeneous isotropic thermoelastic half space with mass diffusion at the stress free, isothermal, isoconcentrated boundary. Using the potential functions and harmonic wave solution, three coupled dilatational waves and a shear wave is obt...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده ادبیات و زبانهای خارجی 1390

abstract the current study set out to address the issue as to whether the implementation of portfolio assessment would give rise to iranian pre-intermediate efl learner autonomy. participants comprised 60 female in pre-intermediate level within the age range of 16-28.they were selected from among 90 language learners based on their scores on language proficiency test -key english test. then, t...

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