نتایج جستجو برای: waves

تعداد نتایج: 113311  

Journal: :جغرافیا و مخاطرات محیطی 0
فیروز مجرد جعفر معصوم پور طیبه رستمی

introduction temperature effects on human activities and natural processes are undeniable. temperature increase, in particular, in the form of heat waves affects all facets of life including architecture, welfare, transport, agriculture and industry. when the intensity and frequency of the waves are high, they can produce major problems. in recent years, the number and intensity of these heat w...

1996
Alexander Figotin

We consider classical acoustic waves in a medium described by a position dependent mass density %(x). We assume that %(x) is a random perturbation of a periodic function % 0 (x) and that the periodic acoustic operator A 0 = ?r 1 % 0 (x) r has a gap in the spectrum. We prove the existence of localized waves, i.e., nite energy solutions of the acoustic equations with the property that almost all ...

R.R Gupta, R.R. Gupta

The present paper concerns with the effect of initial stress on the propagation of plane waves in a rotating transversely isotropic medium in the context of thermoelasticity theory of GN theory of type-II and III. After solving the governing equations, three waves propagating in the medium are obtained. The fastest among them is a quasi-longitudinal wave. The slowest of them is a thermal wave. ...

In this paper, the localized TM surface waves of a nonlinear self-focusingleft-handed slab sandwiched between a uniform medium and a one-dimensionalphotonic crystal (1D PC) is analytically investigated. Our method is based on the firstintegral of the nonlinear Maxwell's equations. For the TM surface waves, the presenceof two electric field components makes the analysis difficult. Therefore, we ...

R Kumar, S Ahuja, S.K Garg

The reflection and transmission of thermoelastic plane waves at an imperfect boundary of two dissimilar fibre-reinforced transversely isotropic thermoelastic solid half-spaces under hydrostatic initial stress has been investigated. The appropriate boundary conditions are applied at the interface to obtain the reflection and transmission coefficients of various reflected and transmitted waves wi...

ژورنال: مهندسی دریا 2015

The principle included in construction of submerged breakwater is to protect beach from morphological changes and the sediment transport against incoming waves. In the present study, boundary element method (BEM) is employed for solving the scattering problem of incident wave passing the vertical and inclined submerged breakwaters with rigid boundaries. The boundary element integral equation wi...

, ,

Survey of advection of cold waves in Iran is the main aim of this study. In this regard, 45 synoptic stations were employed and studied. In order to investigate the thermal advection of cold waves, 1000, 850, 700 and 500 hp levels were reviewed and analyzed. Results indicated that cold waves in Iran most affected thermal advection caused by Tibet- Siberia, Siberias integrated Turkmenistan high-...

محسن‌زاده, مجید, یوسفی, ابراهیم,

Gravitational waves are the last unconfirmed prediction of the general relativity. These waves are tiny fluctuations in world frame that dessipate energy throghout space. The gravitatinal waves spectra of fluctuations can be originated from the non-linear effects during different cosmic evolution periods, especially from initially non-linear and excited vacuum state in the very early universe. ...

میلانی‌مقدم, حسین, نصیریان, شهروز,

 In this letter, titanium dioxide nanoparticles (TiO2) were synthesized via a sol-gel method and combining titanium tetrachloride (TiCl4) and ethanol. The activation energy was investigated on the phase transformation from anatase to rutile in the presence and absence of ultrasound waves. The anatase nanocrystallites were only crystallized up to the calcination of 500 º C. By increasing the cal...

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