We consider the nonlinear beam equation utt + a(x)ut − f(ux)x + uxxxx = 0 in a bounded interval (0, 1) ⊂ R. The equation has an indefinite damping term, i.e., with a damping function a = a(x) possibly changing sign. For this non-dissipative situation we prove the exponential stability of the corresponding linearized system provided ā = ∫ 1 0 a(x)dx > 0 and ‖ a− ā ‖L2≤ τ , for τ small enough. We...

The present work investigates turbulent velocity and temperature fields subject to strong wall injection in a channel using a Direct Numerical Simulation technique. A simplified model problem of the internal flows inside the hybrid rocket motors where a regression process at the wall is idealized by the wall blowing has been considered to gain a better understanding of how the turbulent structu...

Second-order shear deformation theory (SSDT) is employed to analyze vibration of temperature-dependent solar functionally graded plates (SFGP’s). Power law material properties and linear steady-state thermal loads are assumed to be graded along the thickness. Two different types of SFGP’s such as ZrO2/Ti-6Al-4V and Si3N4/SUS304 are considered. Uniform, linear, nonlinear, heat-flux and sinusoida...

during storage, serum separation is a major defect that affects the market share of doogh. therefore, in the present study the effects of high shear stirring and homogenization, as major operation units, on the stability was investigated. to do so, dooghs were stirred at various speeds and time scales (9000 rpm and 11000 rpm for 30 s and 2 min), homogenized at different pressures (0, 20, 50, 80...

Abstract Democracy is one of the most contested words in English language. In Africa, these complexities are compounded by question whether democracy a colonial imposition. Cheeseman and Sishuwa provide historiography debates around democracy, track how narratives have developed over time, argue that there widespread public support for form what they call “consensual democracy.” This not to say...

Turbulence generated by breaking internal waves is an important source of mixing in the ocean interior, and is often interpreted in terms of the stability of the vertical shear. However, observations and numerical studies suggest that vertical internal wave strain may also play a key role in stratified flow stability. Here we model the effects of wave strain by imposing a spatiallyand temporall...