A fully nonlinear development of the thermal self-focusing instability of high power radio waves in the ionosphere in the region near the critical surface is the subject of the present study. In the simulation model studied, a high-powered radio wave in the frequency range 510 MHz, with a 1% amplitude modulation, is launched vertically. In the high latitude geometry this represents a direction ...

We study the evolution of supernova core from the beginning of gravitational collapse of a 15M⊙ star up to 1 second after core bounce. We present results of spherically symmetric simulations of core-collapse supernovae by solving general relativistic ν-radiation-hydrodynamics in the implicit time-differencing. We aim to explore the evolution of shock wave in a long term and investigate the form...

This paper describes the instrumentation for broadband frequency domain thermoreflectance (BB-FDTR), a novel, continuous wave laser technique for measuring the thermal conductivity accumulation function. The thermal conductivity accumulation function describes cumulative contributions to the bulk thermal conductivity of a material from energy carriers with different mean free paths. It can be u...

Rapid surface heating will induce waves in an elastic material. Closed form solutions for the resulting longitudinal and transverse thermal stresses are derived using Laplace Transforms. The model is one-dimensional, consisting of a half-space subjected to a step change in the surface heating. The transverse stress at the wave peak is found to exceed the surface stress for short times, while fo...

In recent years, ultrasonic methods have been developed that can measure the mechanical stiffness of composites. The Lamb wave velocity is directly related to the material parameters, so an effective method exists to ascertain the stiffness of composites by measuring the velocity of these waves. In this study, a Lamb wave measurement system was used to measure the bending and out-of-plane stiff...